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Sampled-Point Network for Classification of Deformed Building Element Point Clouds | Ensemble of shape functions for 3D object classification | Consequences of infertility in developing countries: results of a questionnaire and interview survey in the South of Vietnam | eng_Latn | 10,500 |
3D object classification with point convolution network | 3D ShapeNets: A deep representation for volumetric shapes | Restoring highly corrupted images by impulse noise using radial basis functions interpolation | eng_Latn | 10,501 |
Directional histogram model for three-dimensional shape similarity | A Survey of Shape Analysis Techniques | On the Theory and Practice of Privacy-Preserving Bayesian Data Analysis | eng_Latn | 10,502 |
Joining Extractions of Regular Expressions | TextRunner: Open Information Extraction on the Web | A survey of content based 3D shape retrieval methods | eng_Latn | 10,503 |
Bloom filter based routing for content-based publish/subscribe | Space/time trade-offs in hash coding with allowable errors | Three dimensional surface analyses of pubic symphyseal faces of contemporary Japanese reconstructed with 3D digitized scanner | eng_Latn | 10,504 |
Graph-Based Deformable 3D Object Matching | Shape matching and object recognition using low distortion correspondences | COSMOS - A Representation Scheme for 3D Free-Form Objects | eng_Latn | 10,505 |
Geometric features for voxel-based surface recognition | 3 D Shape Descriptor Based on 3 D Fourier Transform | Graphine: Programming Graph-Parallel Computation of Large Natural Graphs for Multicore Clusters | eng_Latn | 10,506 |
3D graphics on the web: A survey | A survey on Mesh Segmentation Techniques | A high-efficiency bidirectional buck-boost DC-DC converter | eng_Latn | 10,507 |
3D Shape Segmentation with Projective Convolutional Networks | Analysis and synthesis of 3D shape families via deep-learned generative models of surfaces | An Efficient Parallel Data Clustering Algorithm Using Isoperimetric Number of Trees | eng_Latn | 10,508 |
3D bioprinting directly onto moving human anatomy | 3D bioprinting of tissues and organs | Performance based analysis between k-Means and Fuzzy C-Means clustering algorithms for connection oriented telecommunication data | eng_Latn | 10,509 |
what is tesseract | Tesseract is an optical character recognition engine for various operating systems.[2] It is free software, released under the Apache License, Version 2.0,[1][3][4] and development has been sponsored by Google since 2006.[5] In 2006 Tesseract was considered one of the most accurate open-source OCR engines then available.[4][6] | What are Tessellations. The word 'tessera' in latin means a small stone cube. The term has become more specialised and is often used to refer to pictures or tiles, mostly in the form of animals and other life forms, which cover the surface of a plane in a symmetrical way without overlapping or leaving gaps. | eng_Latn | 10,510 |
A topological framework for advancing front triangulation | We study advancing front methods for surface reconstruction. We propose a topological framework based on handlebody theory to implement such methods in a simple and robust way. As an example of the application of this framework we show an implementation of the Ball-Pivoting algorithm. | This is one of several articles that aims to ::: disseminate the research results in developing advanced doctoral ::: paper entitled: Model of System for Technological Surveillance ::: for multiple application to measure the technological gap in ::: Colombian companies. ::: This paper is related to the design of Technological ::: Surveillance, following the Rational Unified Process for software ::: development, commonly known as RUP® [1], UML® [2] and ::: implemented with the programming language C# [3], database ::: engine SQL Server, set to an architectural model of three (3) ::: layers (3-Tier). This document takes into account especially ::: related to requirements, architecture and modeling and ::: subsequent articles are related to testing, evaluation and results of ::: the prototype was implemented and results in the field of ::: technologically surveillance exercises, all in accordance with the ::: objectives of the Doctoral Paper. | eng_Latn | 10,511 |
Please forgive me if this is 'off topic,' the actual page is void of any useful guidelines. I'm new to Blender and started trying to make a model that is more complex than a simple object. Take any normal model, for example a car. Is it normal to make a car in one file that consists of a bunch of different non-connected meshes? Most tutorials I have found make one giant connected object that is (in some way) connected to every part of the whole model. My mind wants to separate the parts, like the wheels wouldn't be 'connected' to the body. I feel like this would make texturing and UV mapping easier, but nobody seems to do this. Texturing different parts of a single giant mesh is challenging for me and I wanted to know if it is bad practice to create lots of 'pieces' to a single model. | Is there any benefit of creating model in one piece or I can create separate pieces and just overlap them to create a visually joint part. For example, the below image were made from two parts 1. Blade 2. Spinner Is there any benefit to model them (e.g. extrude from the spinner) or it is actually ok to have them separated since visually I can achieve the same effect (See picture 2) | Which is correct? Everyone were convinced that he would go to the game. Everyone was convinced that he would go to the game. I think it's "was", because "everyone" is singular, but I just wanted to check. | eng_Latn | 10,512 |
What are good practices for meshes? Do i need force myself to create 3-4-sided polygons like on 1st picture or i can make faces like on 2nd pic? Does it depend on future use of the model (CNC, animation etc). | When should N-Gons be used, and when shouldn't they? Support for N-Gons (polygons consisting of more than 4 vertices) has been in Blender for a while now, but many of us still may not know when to use them, and how to do so effectively. In what situations do N-Gons really come in handy? When should they be just plain left out? Do they have any place in finished models? | Where can the viewport clipping parameters be changed? Zooming in to inspect texture details in 3D view clips some closer faces like shown in the image. It's not the camera view so changing camera settings doesn't help. Where can the distance to the clipping plane be adjusted? | eng_Latn | 10,513 |
So I'm trying to create the face of a character model by starting around the eyes and mouth but when I try and join the edges to connect it creates this weird crease. I want to smooth it out but I can't seem to get rid of it. What I'm doing is pressing F with the selected vertices to create a new face to connect and this happens. Any help to getting rid of it is appreciated, thanks! | I am relatively new to Blender so please excuse me if this is rather amateur! The bottom of my torus has poor surface quality, I have scaled the vertices down for a smaller (variable) tubular radius all the way around the torus and at the bottom the surface quality is awful, with inaccurate shading. Any ideas as to what is wrong and/or how I could fix this? Thanks, itsanate | I dont need this vertices and/or edge. What is the best way to get rid of them? | eng_Latn | 10,514 |
How can you curve the faces of a hexagon? I'm quite a noob at Blender (this is for 2.8 by the way), and I was hoping somebody could help me figure this out. I've been trying to make a 3D hexagon with the side faces curved inwards to sort of look like a six sided star, but I can't quite figure out how to do it. I've tried to delete the top and bottom faces, loop cut the side faces, add an empty plane axes, and then add a simple deform modifier to the side faces with the empty as the origin, but that didn't quite work out properly. The idea was that it would curve all faces in equally and then I could add the top and bottom faces back. Here's kind of the shape I want. It's not quite symmetric since I'm not very good at drawing things, but I'd like for the actual result to be symmetric. Thanks for any help! | How can I make a plane's edges taper inwards? How can I deform one edge or multiple edges of a plane or cube so they are tapered in and rounded equally? | Is it possible to plot a graph of any shape? In school, I have learnt to plot simple graphs such as $y=x^2$ followed by $y=x^3$. A grade or two later, I learnt to plot other interesting graphs such as $y=1/x$, $y=\ln x$, $y=e^x$. I have also recently learnt about trigonometric graphs and circle equations. In the internet, I have seen users posting graphs of different shapes like a heart-shaped graph and a Batman logo-shaped graph. I am sure there are numerous more graphs that I have yet to see. Seeing that the graphs can be shaped into shapes like the Batman logo and a heart brings me to my question: Is it possible to plot a graph of any shape regardless of its complexity? Perhaps, shaped into an outline of a person or a landmark? Why or why not? | eng_Latn | 10,515 |
What do i do when i have two o more meshes and i want to join them | What are the benefits of modeling in one piece, or as separate parts? | How do I join two separate objects so I can edit them as one mesh? | eng_Latn | 10,516 |
shape definition | A shape is the form of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material composition. Psychologists have theorized that humans mentally break down images into simple geometric shapes called geons. | Synonyms: form, figure, shape, contour, profile. These nouns refer to the external outline of a thing. Form is the outline and structure of a thing as opposed to its substance: the pointed form of a pyramid; a brooch in the form of a lovers' knot.. a. The shape and structure of an object: the form of a snowflake. b. The body or outward appearance of a person or an animal; figure: In the fog we could see two forms standing on the bridge. c. A model of the human figure or part of it used for displaying clothes. | eng_Latn | 10,517 |
To find the volume of one of these solids, multiply the area of its circular base by its height | LIFEPAC 7th Grade Math Unit 10 Worktext - HomeSchool-Shelf.com Math 710. Surface Area and Volume. Introduction |3. 1. Solids. 5. Classifying and ... Find the surface area and volume of solid figures using their nets. ... learn how to classify and identify these solids, as well as represent them two- ... cylindera three-dimensional figure with two parallel, congruent, circular bases and a. | Individual Authors - JStor Shape and Shapelessness: The Symbolic Function of Setting in the Fiction. Elizabeth Bowen. ...... Virginia Woolf, and many other figures in the international literary scene. This is a ...... "The Comic Male: Satire in Ellen Glasgow's Queenborough Trilogy." Souther ..... "El Pueblo Espanol: 'The Capital of the World."' Studies in... | eng_Latn | 10,518 |
a digital image of the city : 3 - d isovists and a tribute to kevin lynch . | exploring isovist fields : space and shape in architectural and urban morphology . | Principles of interleukin (IL)-6-type cytokine signalling and its regulation. | eng_Latn | 10,519 |
minimum elastic bounding box algorithm for dimension detection of 3d objects : a case of airline baggage measurement . | detection of regular objects in baggages using multiple x - ray views . | Estimations of worldwide prevalence of chronic hepatitis B virus infection: a systematic review of data published between 1965 and 2013 | eng_Latn | 10,520 |
I am trying to implement a convex decomposition and I need to find the convex vertex on a mesh. Is there a algorithm that I can use to find the convex vertex on a mesh. | I'd like to be able to decompose a concave mesh into a set of convex meshes for 2 reasons: Transparent rendering Physics shapes Is there an algorithm that takes a set of triangles (concave) as input and outputs a number of sets of triangles (convex)? I'd like it to not fill in the holes between parts of the original mesh. I've already come across a small idea: find all the concave edges, and split the meshes along the edge loops. Am I on the right track? How could I implement this? | TeX support works fine in question and answer bodies, and comments can be rendered manually by tapping and selecting Render MathJax. See related question . However, the titles are not rendered which makes the browsing experience less than perfect. See screenshot below. Are there any plans to implement MathJax support in titles? (I'm running Stack Exhange iOS App Version 1.0.0 on an iPhone 4S with iOS 7.1.1) EDIT: I was just informed about asking for the same functionality for the Android app. I guess I shouldn't hope too much then... | eng_Latn | 10,521 |
what is mesh | Mesh (scale) Mesh is a measurement of particle size often used in determining the particle-size distribution of a granular material. For example, a sample from a truckload of peanuts may be placed atop a mesh with 5 mm openings. When the mesh is shaken, small broken pieces and dust pass through the mesh while whole peanuts are retained on the mesh. A commercial peanut buyer might use a test like this to determine if a batch of peanuts has too many broken pieces. | Grid or Mesh is defined as smaller shapes formed after discretisation of geometric domain. Mesh or Grid can be in 3- dimension and 2-dimension. Meshing has applications in fields of Geography, designing, CFD (Computational Fluid Dynamics). and many more places. The 2-dimensional meshing includes simple polygon, polygon with holes, multiple domain and curved domain. | eng_Latn | 10,522 |
what is mesh? | mesh - the number of openings per linear inch of a screen; measures size of particles; a 100 mesh screen; 100 mesh powdered cellulose linear measure, linear unit - a unit of measurement of length in, inch - a unit of length equal to one twelfth of a foot | A mesh is a barrier made of connected strands of metal, fiber, or other flexible/ductile materials. A mesh is similar to a web or a net in that it has many attached or woven strands. 1 1 Types of mesh. 2 Uses of mesh. | eng_Latn | 10,523 |
what is mesh topology | Mesh network or mesh topology definition is a topology of network which its nodes transmit data for the network. Each node cooperates in the relaying of data or information in the network. The routing technique or the flooding technique is the design of how the mesh topology works in a network. | A mesh network is a network built from devices that all work together to distribute all the data. They can be wired and use an algorithm like shortest-path bridging to efficiently route data through the whole network using cables and routers on certain nodes (a node is an address on a network), but they really shine when they are wireless. | eng_Latn | 10,524 |
definition of mesh | Wiktionary(0.00 / 0 votes)Rate this definition: 1 mesh(Noun) A structure made of connected strands of metal, fiber, or other flexible/ductile material, with evenly spaced openings between them. 2 mesh(Noun) The opening or space enclosed by the threads of a net between knot and knot, or the threads enclosing such a space. | Grid or Mesh is defined as smaller shapes formed after discretisation of geometric domain. Mesh or Grid can be in 3- dimension and 2-dimension. Meshing has applications in fields of Geography, designing, CFD (Computational Fluid Dynamics). and many more places. The 2-dimensional meshing includes simple polygon, polygon with holes, multiple domain and curved domain. | eng_Latn | 10,525 |
Is it possible to vary material colour depending upon thickness of the underlying mesh? | Distance from the surface as an input node for use with volumetric materials | Removing unwanted appearance of underlying mesh | eng_Latn | 10,526 |
Shading / smoothing - how does it work with edges, faces, vertices? | What is vertex and edge shading? | Cannot translate vertice/edge will duplicate | eng_Latn | 10,527 |
Cutting a mesh with another mesh | Making holes in a mesh | How to merge all scene geometry into a single mesh? | eng_Latn | 10,528 |
what is the 3d shell | In 3D computer graphics, 3D modeling is the process of developing a mathematical representation of any surface of an object in three dimensions via specialized software. The product is called a 3D model. Someone who works with 3D models may be referred to as a 3D artist. It can be displayed as a two-dimensional image through a process called 3D rendering or used in a computer simulation of physical phenomena. The model can also be physically created using 3D printing devices. Models may be creat | In 3D computer graphics, 3D modeling (or three-dimensional modeling) is the process of developing a mathematical representation of any three-dimensional surface of an object (either inanimate or living) via specialized software. The product is called a 3D model. | eng_Latn | 10,529 |
what is a primitive solid | A primitive solid is a âbuilding block' that you can use to work with in 3D. Rather than extruding or revolving an object, AutoCAD has some basic 3D shape commands at your disposal. From these basic primitives, you can start building your 3D models. In many cases, you get the same result from drawing circles and rectangles and then extruding them, but doing it one command is generally faster. Using these with Boolean operations can be a very effective way of drawing in 3D. | 1 A flexible rodlike structure that forms the main support of the body in the lowest chordates; a primitive spine. A similar structure found in the embryos of vertebrates from which the spine develops. | eng_Latn | 10,530 |
Measurability of partial derivatives | On the Differentiability of Functions of Several Variables | Temporal order deterioration and circadian disruption with age 1. Central and peripheral mechanisms | eng_Latn | 10,531 |
A method of enhancing the lower frequency components of the brainstem auditory evoked potential (BAEP) and consequently reducing the number of sweeps required for a suitable signal-to-noise-ratio is presented. The algorithm, methods, and experimental results are discussed. The results suggest that some single-sweep signal components have polarities that are opposite to the ensemble average polarity. > | The Emergence of Electrophysiology as an Aid to Neurology. Electrophysiologic Equipment and Electrical Safety. Electroencephalography General Principles and Clinical Applications. Neonatal and Pediatric Electroencephalography. Ambulatory EEG Monitoring. Longterm Scalp or Intracranial EEG. Brain Mapping. Depth Electrography and Electrocorticography. Clinical Electromyography. Nerve Conduction Studies. Electrophysiologic Study of Disorders. Late Responses and the 'Silent Period'. The Blink Reflex as a Clinical Test. Electrophysiologic Evaluation of Tremor and Central Disorder of Movement. Testing of Autonomic Function. Electroretinography. Visual Evoked Potentials. Visual Evoke Potentials in Children. Brainstem Auditory Evoked Potentials in Neurology : Methodology, Inteerpretation and Clinical Application. Brainstem Auditory Evoked Potentials in Pediatrics. Somatosensory Evoked Potentials. Motor Evoked Potentials. Event-Related (Endogenous) Potentials. Intraoperative Monitoring By Evoked Potential Techniques. Electronystagmography. The Polysomnographic Evaluation of Sleep Disorders in Humans. Electrophysiologic Evaluaton of Brain Death : A Critical Appraisal | 1. After traumatic spinal cord injury (SCI), histological and neurological consequences are developing for several days and even weeks. However, little is known about the dynamics of changes in spinal axonal conductivity. The aim of this study was to record and compare repeated spinal cord evoked potentials (SCEP) after SCI in the rat during a 4 weeks’ interval. These recordings were used: (i) for studying the dynamics of functional changes in spinal axons after SCI, and (ii) to define the value of SCEP as an independent outcome parameter in SCI studies. | eng_Latn | 10,532 |
Understanding how communication sounds are encoded in the central auditory system is critical to deciphering the neural bases of acoustic communication. Songbirds use learned or unlearned vocalizations in a variety of social interactions. They have telencephalic auditory areas specialized for processing natural sounds and considered as playing a critical role in the discrimination of behaviorally relevant vocal sounds. The zebra finch, a highly social songbird species, forms lifelong pair bonds. Only male zebra finches sing. However, both sexes produce the distance call when placed in visual isolation. This call is sexually dimorphic, is learned only in males and provides support for individual recognition in both sexes. Here, we assessed whether auditory processing of distance calls differs between paired males and females by recording spiking activity in a secondary auditory area, the caudolateral mesopallium (CLM), while presenting the distance calls of a variety of individuals, including the bird itself, the mate, familiar and unfamiliar males and females. In males, the CLM is potentially involved in auditory feedback processing important for vocal learning. Based on both the analyses of spike rates and temporal aspects of discharges, our results clearly indicate that call-evoked responses of CLM neurons are sexually dimorphic, being stronger, lasting longer, and conveying more information about calls in males than in females. In addition, how auditory responses vary among call types differ between sexes. In females, response strength differs between familiar male and female calls. In males, temporal features of responses reveal a sensitivity to the bird's own call. These findings provide evidence that sexual dimorphism occurs in higher-order processing areas within the auditory system. They suggest a sexual dimorphism in the function of the CLM, contributing to transmit information about the self-generated calls in males and to storage of information about the bird's auditory experience in females. | Estradiol acts as a neuromodulator in brain regions important for cognition and sensory processing. Estradiol also shapes brain sex differences but rarely have these concepts been considered simultaneously. In male and female songbirds, estradiol rapidly increases within the auditory forebrain during song exposure and enhances local auditory processing. We tested whether G-protein-coupled estrogen receptor 1 (GPER1), a membrane-bound estrogen receptor, is necessary and sufficient for neuroestrogen regulation of forebrain auditory processing in male and female zebra finches (Taeniopygia guttata). At baseline, we observed that females had elevated single-neuron responses to songs vs males. In males, narrow-spiking (NS) neurons were more responsive to conspecific songs than broad-spiking (BS) neurons, yet cell types were similarly auditory responsive in females. Following acute inactivation of GPER1, auditory responsiveness and coding were suppressed in male NS yet unchanged in female NS and in BS of both sexes. By contrast, GPER1 activation did not mimic previously established estradiol actions in either sex. Lastly, the expression of GPER1 and its coexpression with an inhibitory neuron marker were similarly abundant in males and females, confirming anatomical similarity in the auditory forebrain. In this study, we found: (1) a role for GPER1 in regulating sensory processing and (2) a sex difference in auditory processing of complex vocalizations in a cell type-specific manner. These results reveal sex specificity of a rapid estrogen signaling mechanism in which neuromodulation accounts and/or compensates for brain sex differences, dependent on cell type, in brain regions that are anatomically similar in both sexes. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,533 |
Neuronal activity evoked by chronically implanted intracortical microelectrodes | Auditory Brainstem Prosthesis: Biocompatability of Stimulation | Lack of Marburg Virus Transmission From Experimentally Infected to Susceptible In-Contact Egyptian Fruit Bats. | eng_Latn | 10,534 |
Achromatic color matching as a function of apparent target orientation, target and background luminance, and lightness or brightness instructions | Simultaneous contrast and gamut relativity in achromatic color perception | Attention Network Test reveals alerting network dysfunction in multiple sclerosis | eng_Latn | 10,535 |
The Sterile insect Technique (SiT) has been used successfully to control or eradicate fruit flies. The commonly observed inferiority of mass-reared males, compared with wild males, when they are paired with wild females, is apparently due to their inadequate courtship. Anastrepha ludens males produce two types of wing vibration during courtship and mating, the "calling sound" and the "premating or precopulatory sound". There were clear differences in the calling songs between successful and unsuccessful courtships in sterile (irradiated) and fertile Mexican flies. Among sterile flies, successful males produce longer buzzes, shorter interpulses and a higher power spectrum in the signal. Fertile flies showed the same trend. For mating songs a significant dif- ference occurred in two parameters: power spectrum between sterile and fertile flies with respect to the type of song, and the signal duration and intensity were greater in non-irradiated flies. Calling songs of wild flies compared with laboratory grown flies from Mexico had shorter interpulses, longer pulses, and a greater power spectrum. However, in the case of premating songs, the only difference was in the intensity, which was sig- nificantly greater in wild males. An unexpected result was not observing pulses during pheromone deposition in wild males from Costa Rica. Comparing the premating songs of wild flies from Costa Rica and Mexico, no significant differences were observed in the duration, and the intensity of the signal was slightly greater in flies from Mexico. Rev. Biol. Trop. 57 (Suppl. 1): 257-265. Epub 2009 November 30. | The evolutionary effects of crowding on male courtship behavior were studied using wild and mass-reared medflies. Mass-reared strains had been raised under highly crowded conditions in mass-rearing facilities for approximately 75, 180, and 238 generations. Pre-mounting courtship was facultatively shortened in both wild and mass-reared males under conditions of greater crowding. The courtship behavior of males of mass-reared strains was also shorter than that of wild males under similar conditions of crowding. Shorter courtships are probably advantageous for males in crowded conditions because they reduce the likelihood of the courtship being interrupted by other flies. Several types of data indicated that males rather than females were responsible for shortened courtships. We conclude that heritable variation in male courtship behavior has persisted in a wild population despite its overall relatively low genetic variability, and that genetic changes in mass-reared strains have altered the range of faculta... | Immediate memory for visually presented verbal material is disrupted by concurrent speech, even when the speech is unattended and in a foreign language. Unattended noise does not produce a reliable decrement. These results have been interpreted in terms of a phonological short-term store that excludes non-speechlike sounds. The characteristics of this exclusion process were explored by studying the effects of music on the serial recall of sequences of nine digits presented visually. Experiment 1 compared the effects of unattended vocal or instrumental music with quiet and showed that both types of music disrupted STM performance, with vocal music being more disruptive than instrumental music. Experiment 2 attempted to replicate this result using more highly trained subjects. Vocal music caused significantly more disruption than instrumental music, which was not significantly worse than the silent control condition. Experiment 3 compared instrumental music with unattended speech and with noise modulated in... | eng_Latn | 10,536 |
By the use of two-color threshold technique, the critical duration was measured at 10 retinal-illuminance levels of the adapting field. The critical duration does not always decrease monotonically with increase of the adapting retinal illuminance; it sometimes decreases at first and then increases again before it finally decreases. All these results can be explained very clearly by the hypothesis that the critical duration is determined by the state of adaptation of the cone system concerned. If it is well adapted, the critical duration is short, in general. The experimentally obtained critical-duration-vs-adapting-illuminance curve is composed of component tc–E curves of the underlying cone systems, the π1, π2, π4, and π5 mechanisms. The differences among these mechanisms, as to their critical-duration characteristics; were found; the first two, or blue systems, had long critical durations and less decrease with adaptation but the last two had short critical durations and considerable decrease with adaptation. | Visual masking typically occurs when mask and target are separated in time by less than 100 ms, and the form of this interaction might be expected to depend on the latency of the target and mask signals. We track psychophysically the time course of signals from the two colour-opponent channels by using forward and backward masking, in which mask and target each stimulate only one colour channel. Stimuli resemble those used in the Cambridge Colour Test,1 in that spatial luminance noise is used to ensure that neither edge artifacts nor luminance differences can be used as a cue to discrimination of the stimulus against the field. Additionally, we introduce temporal luminance noise in order to ensure that our very brief chromatic modulations are not detected via the magnocellular pathway. Our data suggest that there is no large latency difference between the two chromatic channels of the early visual system, and that previous evidence for such a difference may instead reflect a difference between chromatic and achromatic pathways. © 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S165–S169, 2001 | To investigate whether there is a circadian regulation of insulin secretion, rats were adapted to a feeding regimen of six meals equally distributed over 24 h. Under these conditions basal glucose and insulin levels increased during the light phase and decreased during the dark phase. Maximal blood glucose responses were fairly similar during the six different meals, but glucose increments were clearly delayed during the last two meals consumed during the light period. Insulin increments were highest during the dark phase and clearly diminished during the second half of the light phase. This situation was reversed when the scheduled meals were replaced by i.v. glucose infusions, i.e., no significant differences were detected between insulin responses, whereas glucose increments were reduced during the dark period. These results show that there is a circadian regulation of basal blood glucose and feeding-induced insulin responses, which is independent of the temporal distribution of feeding activity. | eng_Latn | 10,537 |
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper. | Although aggression is a common symptom of psychiatric disorders the drugs available to treat it are non-specific and can have unwanted side effects. In this study we have used a behavioural platform in a phenotypic screen to identify drugs that can reduce zebrafish aggression without affecting locomotion. In a three tier screen of ninety-four drugs we discovered that caffeine and sildenafil can selectively reduce aggression. Caffeine also decreased attention and increased impulsivity in the 5-choice serial reaction time task whereas sildenafil showed the opposite effect. Imaging studies revealed that both caffeine and sildenafil are active in the zebrafish brain, with prominent activation of the thalamus and cerebellum evident. They also interact with 5-HT neurotransmitter signalling. In summary, we have demonstrated that juvenile zebrafish are a suitable model to screen for novel drugs to reduce aggression, with the potential to uncover the neural circuits and signalling pathways that mediate such behavioural effects. | Summary. The paper reflects on the author’s experience and discusses how statistical theory, sound judgment and knowledge of the context can work together to best advantage when tackling the wide range of statistical problems that can arise in practice. The phrase ‘pragmatic statistical inference’ is introduced. | eng_Latn | 10,538 |
In the framework of a high-frequency transmission-line theory for nonuniform lines (TLST), new reflection and transmission coefficients are derived using generalized definitions of equivalent quantities from the classical transmission-line theory. This leads to local and frequency-dependent reflection and transmission coefficients expressed in terms of matrizant elements. These quantities are needed to describe networks of nonuniform radiating transmission lines. A comparison between the currents calculated in the approach of TLST and those calculated with the aid of the new transmission and reflection coefficients shows an excellent agreement. | As a common secondary disease, edema after traumatic brain injury (TBI) can increase brain volume, resulting in elevated intracranial pressure (ICP), brain shift, and cerebral hernia, and can eventually lead to death. The real-time continuous monitoring of edema may significantly reduce mortality and disability. In this paper, a dual-parameter synchronous monitoring system of edema based on the reflection and transmission characteristics of the two-port test network was established; 15 rabbits were chosen to perform 24-h reflection phase shift (RPS) and transmission phase shift (TPS) simultaneously monitoring the experiments of brain edema. With the development of brain edema, the variation law of the RPS and TPS was investigated. Combined with the power amplitude spectrum and the principle of the two-port test network, the influence of frequency on the detection sensitivity of RPS and TPS was analyzed in detail, and the optimal detection frequency point was found. After that, the classification of three different degrees of edema is performed by the BP algorithm. In the animal experiment, the RPS showed a continuous increasing trend within time, and it presented the variation of (9.35910° ± 1.65702°), (12.60117° ± 2.30218°), and (16.33423° ± 2.11118°) after 6, 12, and 24 h, respectively. Meanwhile, the TPS showed a continuous downward trend with the variation of (-12.62555° ± 0.99441°), (-19.23976° ± 1.27488°), and (-27.26285° ± 2.62291°) after 6, 12, and 24 h, respectively. The RPS was negatively correlated with the TPS. The RPS and the TPS together as a recognition feature can achieve 100% accurate classification of three different brain edema severities. Based on these results, it can be concluded that the system established in this paper can monitor gradual increases in brain edema severity. Furthermore, neither the RPS nor the TPS can be set as the recognition feature alone to achieve the completely accurate classification, which shows the necessity of presenting two parameters in the monitoring process. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,539 |
Spinal cord monitoring during surgery using evoked spinal potentials (ESP) is now popular. In cats, ESPs due to both sciatic nerve (SN-ESP) and spinal cord stimulation (SC-AESP and SC-DESP) were recorded from the epidural space. Both SN-ESP and SC-AESP were compared by parameter studies. Stimulus frequencies up to 100 Hz did not significantly alter the SC-AESP, whereas the later components of the SN-ESP decreased greatly in amplitude. The SN-ESP was more sensitive to asphyxia than the SC-AESP. Augmentation of the ESP occurred approximately 5 minutes after the asphyxia was introduced, which was interpreted as an impending sign of anoxia of the spinal cord. The SN-ESP had more potentials arising from synaptic and postsynaptic activities, while the SC-AESP was mainly derived from the spinal tracts. To monitor the function of the spinal cord, both methods should be used. | 1. After traumatic spinal cord injury (SCI), histological and neurological consequences are developing for several days and even weeks. However, little is known about the dynamics of changes in spinal axonal conductivity. The aim of this study was to record and compare repeated spinal cord evoked potentials (SCEP) after SCI in the rat during a 4 weeks’ interval. These recordings were used: (i) for studying the dynamics of functional changes in spinal axons after SCI, and (ii) to define the value of SCEP as an independent outcome parameter in SCI studies. | We investigate the polyhedral structure of the Periodic Event Scheduling Problem (PESP), which is commonly used in periodic railway timetable optimization. This is the first investigation of Chvatal closures and of the Chvatal rank of PESP instances. ::: In most detail, we first provide a PESP instance on only two events, whose Chvatal rank is very large. Second, we identify an instance for which we prove that it is feasible over the first Chvatal closure, and also feasible for another prominent class of known valid inequalities, which we reveal to live in much larger Chvatal closures. In contrast, this instance turns out to be infeasible already over the second Chvatal closure. We obtain the latter result by introducing new valid inequalities for the PESP, the multi-circuit cuts. In the past, for other classes of valid inequalities for the PESP, it had been observed that these do not have any effect in practical computations. In contrast, the new multi-circuit cuts that we are introducing here indeed show some effect in the computations that we perform on several real-world instances - a positive effect, in most of the cases. | eng_Latn | 10,540 |
Continuous electroencephalogram (EEG) sleep studies were obtained on healthy full-term and preterm infants at matched conceptional ages. Studies were recorded under environmentally controlled conditions. Eighteen healthy preterm infants were matched to 18 full-term infants based on conceptional age, sex, race and socioeconomic class. The initial 3 hours of a 12-hour recording were simultaneously recorded on paper and computer. The visually scored data based on the paper recordings for sleep architecture and continuity measures were studied. Differences in each sleep organization for the preterm infants included the following: a longer ultradian sleep cycle (70 minutes vs. 53 minutes, p = 0.02) was noted. More abundant tracé alternant (34% vs. 28%, p = 0.02) and less abundant low-voltage irregular active sleep (13% vs. 17%, p = 0.05) were noted. Although no differences were observed for sleep latency and efficiency, the preterm infants had fewer numbers and shorter durations of arousals, fewer body movements and rapid eye movement (REM) (p < 0.01), particularly during quiet sleep. The extrauterine experience or the earlier birth of the preterm infant may influence specific sleep architecture and continuity measures when compared with the sleep of full-term infants who experienced a complete intrauterine gestation. | We tested the hypothesis that the sensory-motor characteristics of aerodigestive reflexes are dependent on stimulus type and volumes, sleep or awake states, and maturation. Thirteen neonates were studied at 33.6 ± 0.5 wk (time 1) and 37.3 ± 0.5 wk (time 2) postmenstrual age using multimodal provocative esophageal manometry concurrent with video polysomnography. Effects of graded volumes (399 infusions at time 1, 430 infusions at time 2) of midesophageal stimulation with air, water, and apple juice on the sensory thresholds and recruitment frequency of upper esophageal sphincter (UES), esophageal body, and lower esophageal sphincter (LES) reflexes were investigated during sleep and awake states. Sensory thresholds for aerodigestive reflexes between maturational stages were similar. Increased frequency recruitment of UES contractile reflex, LES relaxation reflex, and peristaltic reflexes were noted at time 2 (all, P < 0.05). Graded stimulus-response relationships were evident at time 1 and time 2 during awake and sleep states (P < 0.05). Secondary peristalsis vs. esophago-deglutition response proportions during sleep at time 1 vs. time 2 (P = 0.001) and awake vs. sleep at time 2 (P = 0.02) were distinct. We concluded that sensory-motor effects of esophageal mechanosensitivity, osmosensitivity, and chemosensitivity are advanced in sleep with maturation. Sleep further modulates the frequency recruitment and the type of aerodigestive reflexes. | We identify a stability/instability trichotomy for a class of non-negative continuous-time Lur’e systems. Asymptotic as well as input-to-state stability concepts (ISS) are considered. The presented trichotomy rests on Perron-Frobenius theory, absolute stability theory and recent ISS results for Lur’e systems. | eng_Latn | 10,541 |
Averaged responses of the occipital lobes to flashes imposed along the midline of the upper part of the retina are larger and of shorter latency than responses to flashes imposed on the lower retina. Since reaction times also are shorter when the upper retina is stimulated, this study provides further evidence for the generalization that reaction time varies inversely with amplitude and directly with latency of the evoked response. | Electroretinograms (ERGs) were elicited by hemicircular (half-disc) stimuli to the upper, lower, temporal and nasal maculas of 26 normal subjects, and the amplitudes and implicit times of the ERGs from opposing macular regions were compared. The amplitudes of a-wave, b-wave and oscillatory potentials (OPs) were significantly larger in the upper macular region than in the lower macular region (P less than 0.05). The amplitudes of a- and b-waves did not differ significantly between temporal and nasal macular regions, but OPs showed enormous asymmetry, with significantly larger amplitudes in the temporal retina than in the nasal retina (P less than 0.001). The implicit times of a-waves, b-waves and OPs did not differ significantly between upper and lower retina, or between temporal and nasal retina. These findings aided analysis of the ERG of a patient with a retinal defect. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,542 |
Specifically, a concentration-response function based on Schwartz et al. | The concentration-response function is based on work by Schwartz and colleagues. | The concentration-response function is not related to Schwartz's work. | eng_Latn | 10,543 |
Predicting speech intelligibility based on a correlation metric in the envelope power spectrum domain | Refinement and validation of the binaural short time objective intelligibility measure for spatially diverse conditions | 5-HT3 receptor ligands lack modulatory influence on acetycholine release in rat entorhinal cortex | eng_Latn | 10,544 |
Modulation of the N400 potential during auditory phonological/semantic interaction. | The Effect of Signal‐to‐Noise Ratio on Linguistic Processing in a Semantic Judgment Task: An Aging Study | Porin channels in intact cells of Escherichia coli are not affected by Donnan potentials across the outer membrane. | eng_Latn | 10,545 |
Additive conjoint measurement and the resistance toward falsifiability in psychology | The Rasch model and conjoint measurement theory from the perspective of psychometrics | Finitely additive invariant measures. I | eng_Latn | 10,546 |
A local-ether model of wave propagation complying with the Sagnac correction in the global positioning system | A local-ether wave equation and the Galilean-invariant electromagnetic force law | Self-insight into emotional and cognitive abilities is not related to higher adjustment | eng_Latn | 10,547 |
Differences in the neural basis of automatic auditory and visual time perception: ERP evidence from an across-modal delayed response oddball task | Cerebral Evoked Potentials in Patients at an Early Stage of Schizophrenia | Venous thromboembolism rates in patients with lower limb immobilization after Achilles tendon injury are unchanged after the introduction of prophylactic aspirin: audit | eng_Latn | 10,548 |
Activation of Human Auditory Cortex in Retrieval Experiments: An fMRI Study | A Comparison of Visual and Auditory Motion Processing in Human Cerebral Cortex | Exogenous growth factors do not affect the development of individually cultured murine embryos | kor_Hang | 10,549 |
The MIME effect: absence of normal modes corresponding to vibronic spacings | Emergence of collective intonation in the musical performance of crowds | Daily behavioral manipulation increases the total immunoreactive serum neurophysin concentrations irrespective of the duration of water deprivation in rats | eng_Latn | 10,550 |
Magnetic and electrical stimulation of the auditory cortex for intractable tinnitus | Tinnitus Suppression by Cochlear Implants | 5-HT3 receptor ligands lack modulatory influence on acetycholine release in rat entorhinal cortex | eng_Latn | 10,551 |
On the Theory of Fractional Order Differential Games of Pursuit | Differential Games of Pursung in the Systems with Distributed Parameters and Geometrical Restrictions | Brain Injury Does Not Alter the Intrinsic Differentiation Potential of Adult Neuroblasts | eng_Latn | 10,552 |
Optical Storage and Retrieval: Memory, Neural Networks, and Fractals | Correlometry of random optical fields | An utter refutation of the ‘Fundamental Theorem of the HapMap’ | kor_Hang | 10,553 |
High-Speed Frequency Modulation of a 460-GHz Gyrotron for Enhancement of 700-MHz DNP-NMR Spectroscopy | Simulation Investigations and Optimization of a Millimeter-Wave Gyrotron for Its Tunability Using Magnetic and Thermal Tuning Schemes | Kynurenic acid blocks nicotinic synaptic transmission to hippocampal interneurons in young rats. | eng_Latn | 10,554 |
Early cortical processing of linguistic pitch patterns as revealed by the mismatch negativity | Hemispheric asymmetries in phonological processing of tones versus segmental units | Absolute stability of global pattern formation and parallel memory storage by competitive neural networks | eng_Latn | 10,555 |
Objectives : The purpose of this study was to determine the time course of low-frequency ( Methods : Neuromagnetic measurements were done with a 37-channel first-order gradiometer system. The stimulus was a 1 kHz toneburst of 10 s duration presented at fixed 20 s intervals. The averaged data (high-pass filtered, 0.03 Hz cut-off) were analyzed using the model of an equivalent current dipole with time-invariant location and orientation (fixed dipole). Results : In the grand average of the subjects with the best signal-to-noise ratio, the SF exhibited adaptation with a time constant of 3.6 s. After stimulus offset, the amplitude of the dipole moment dropped to a lower level within 300 ms and decayed exponentially to the baseline thereafter (time constant 2.7 s). Conclusions : A two-component model is proposed: One component roughly follows the envelope of the stimulus, the other behaves like a leaky integrator. A better understanding of near-DC fields appears to be crucial for the understanding of the relationship between magnetoencephalography and other functional imaging techniques like functional magnetic resonance imaging and positron emission tomography. | To seek for correlates of an interaction between auditory and somatosensory processing, the brain's magnetic field in response to simultaneously presented auditory (A) and tactile (T) stimuli was compared with the sum of the respective unimodal responses (A+T). The stimuli were binaural 1047-Hz tone bursts of 60 dB sensation level and tactile pressure pulses to the right thumb. The mean interval between two stimuli of the same modality was 1.95 s. The magnetic field was recorded using a 306-channel whole-scalp neuromagnetometer. A clear audiotactile interaction was revealed in the hemisphere contralateral to the side of tactile stimulation in six of eight subjects, whereas in the ipsilateral hemisphere an interaction was noticed in only three subjects. The time courses of these audiotactile interaction fields typically showed major deflections of opposite polarities around 140 and 220 ms. The first deflection appeared to arise in the region of the secondary somatosensory cortex (SII). The polarity of this interaction was consistent with the view that the auditory stimulus resulted in a partial inhibition in SII. In two subjects, strong indications of auditory contributions to the interaction were available, although in different hemispheres. The relatively high interindividual variability of the observed interaction, which represents potential neural substrates for multisensory integration, could indicate that the way subjects perceive the simultaneous presentation of auditory and tactile stimuli differs. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,556 |
The responses to electrical stimulation of a number of alcyonarian, zoanthid and madreporarian corals are described. All groups studied except gorgonids show extensive coordination over the colony. In Sarcophyton (Alcyonacea) the response is typically local at first but eventually a wave of polyp retraction can be made to spread over the colony. The astraeid corals and the alcyonarian Tubipora have over the whole colony a through-conducting system which has refractory and neuromuscular properties similar to those found in the mesenteries of actinians. In the zoanthid Palythoa successive shocks produce excitation which spreads progressively farther across the colony at each shock for as many as fifty shocks at two-second intervals. The perforate corals , Acropora, Goniopora and Porites respond to a single shock by a co-ordinated retraction of many polyps. Except in Acropora , it is characteristic of the perforate corals studied that stimulation at one point never spreads over the whole colony no matter how many stimuli are applied. The responses of the individual polyps of many corals, including Fungia , are described, and in all there is a similarity to the column, disk and tentacle responses already known in actinians, e.g. Calliactis . The concept of interneural facilitation has been analyzed by use of a working model which shows that the simple theory is inadequate as an explanation of transmission between polyps of certain species because the predicted transmission distances are either too variable or too small compared with the actual distances observed at the first electrical stimulus of the animal. The properties of the co-ordinating systems between the polyps of the various groups of corals have been considered as variations on a common theme, conduction between units which form a network. The various stages from poor co-ordination, through progressive spread at each successive stimulus, to a through-conducting condition have been interpreted as a reflexion of increasing probability of transmission from one all-or-nothing unit of the pathway to the next unit in a population of a large number of units, only a proportion of which may be active at any one time. The units may be interpreted as neurones, as is probable in parts of a single polyp, or as small regions such as polyps within which there is normally through-conduction at the first stimulus. | 1. Luminescence in Ptychodera and Balanoglossus is normally neurally mediated. ::: ::: 2. The main luminescence appears to be intracellular; in addition a luminous slime is secreted. ::: ::: 3. The response of individual photocytes is all-or-none, but requires neuroeffector facilitation which grades intensity by recruitment (in contrast to crustacean muscle). ::: ::: 4. Repetitive discharge, both to mechanical and single electrical stimuli, is considered to be a prime factor together with interneural and neuro-effector facilitation, in determining spread of excitation in the general plexus. ::: ::: 5. Four types of spread of luminescence occur, differing in conduction velocity polarization of spread, area of spread, necessary conditions for elicitation and adequate stimulus. At least three different neural pathways are involved. ::: ::: 6. Prolonged autoexcitatory displays produce luminous waves arising repetitively from the same locus and from multiple loci; the general plexus is implicated. ::: ::: 7. There is a diurnal rhythm of responsiveness to stimuli. This is attributed to the photocyte rather than to the nervous system. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,557 |
Transient (click)-evoked oto-acoustic emissions (TEOAEs) and distortion product oto-acoustic emissions (DPOAEs) were recorded in a feasibility study in 7 healthy mixed-breed dogs using the ILO 92 OAE analyser (Otodynamics, Hartfield, UK). Five dogs were found to have normal hearing in both ears and 2 dogs in the left ear only following otoscopy, tympanometry and auditory brainstem response audiometry. Twelve sets of TEOAEs (click-evoked) to 80 dB peSPL click stimulus and 9 sets of DPOAEs (2F1-F2) to 8 different stimulus levels of the primary tones (L1/L2) were collected at 11 test frequencies (F2) in these normal-hearing dogs. TEOAEs were successfully recorded in 11 of the 12 ears using the default user setting and in all 12 ears using the quickscreen program. DPOAEs were successfully recorded in all 9 ears tested. While the TEOAEs parameters matched those for humans, the average signal-to-noise ratio of DPOAEs was considerably higher in the dogs. Stimulus levels at 55/55, 55/45 and 55/35 dB SPL were demonstrated to produce DPOAEs that seem to reflect the active dynamic status of the outer hair cell system. Postmortem DPOAEs at these stimulus levels and TEOAEs at 80 Db peSPL could not be elicited 5 min following euthanasia of dogs. However, DPOAEs could still be recorded albeit with reduced amplitude at stimulus levels where L1 > 55 dB SPL. The results suggest that TEOAEs and DPOAEs in dogs have the potential to provide valuable insights into their mechanisms of generation, and the specific role and behaviour of outer hair cells of the cochlea in certain pathological conditions, particularly in drug-induced ototoxicity, in humans. | The oto-acoustic emissions generated in response to two-tone stimulation have been studied in the ear canal sound pressure of three species of rodent: rat (Rattus norvegicus), guinea pig (Cavia porcellus) and Mongolian gerbil (Meriones unguiculatus). The level of acoustic intermodulation distortion evoked by equal-level stimuli at different frequencies can be related to the threshold frequency response curves obtained by other workers for these species using evoked electrical responses or behavioural techniques. Gerbils produce higher levels of distortion below 9 kHz than the rat or guinea pig. This may be due to the greater efficiency of the middle ear at low frequencies. Growth of 2f1−f2 with equal-level, widely-spaced stimuli ( f 2 f 1 = 1.3 ) can be divided into two regions. The low intensity part of the curve grows with a slope of 1 and saturates above 60 dB SPL. With higher level stimuli, there is rapid growth with a slope of, or approaching 3. Differences in growth rate may distinguish a low-level, saturating response which owes its response characteristics to the activity of hair cells from a high-level response attributable to passive mechanical properties of the cochlea. A broad, low-frequency spread of distortion components is seen as the stimulus frequencies converge. Sharp interruptions in the growth curves of these components may be due to interaction between out-of-phase components of ‘low’ and ‘high’ level distortion. The distortion in the gerbil can be distinguished from that of the other two species in a number of details. Structural specialisation of the gerbil cochlea may contribute to these distinctive features. | Distortion-product otoacoustic emissions (DPOAEs) arise in the cochlea in response to two tones with frequencies f1 and f2 and mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Wave interference between these components limits the accuracy of DPOAEs when evaluating the function of the cochlea with conventional continuous stimulus tones. Here, DPOAE components are separated in the time domain from DPOAE signals elicited with short stimulus pulses. The extracted nonlinear-distortion components are used to derive estimated distortion-product thresholds (EDPTs) from semi-logarithmic input-output (I/O) functions for 20 normal-hearing and 21 hearing-impaired subjects. I/O functions were measured with frequency-specific stimulus levels at eight frequencies f2 = 1,…, 8 kHz (f2/f1 = 1.2). For comparison, DPOAEs were also elicited with continuous primary tones. Both acquisition paradigms yielded EDPTs, which significantly correlated with behavioral thresholds (p < 0.001) and enabled derivation of estimated hearing thresholds (EHTs) from EDPTs using a linear regression relationship. DPOAE-component separation in the time domain significantly reduced the standard deviation of EHTs compared to that derived from continuous DPOAEs (p < 0.01). In conclusion, using frequency-specific stimulus levels and DPOAE-component separation increases the reliability of DPOAE I/O functions for assessing cochlear function and estimating behavioral thresholds. | eng_Latn | 10,558 |
The field of functional neuroimaging (FNI) methodology has developed into a mature but evolving area of knowledge and its applications have been extensive. A general problem in the analysis of FNI data is finding a signal embedded in noise. This is sometimes called signal detection. Signal detection theory focuses in general on issues relating to the optimization of conditions for separating the signal from noise. When methods from probability theory and mathematical statistics are directly applied in this procedure it is also called statistical inference. In this paper we briefly discuss some aspects of signal detection theory relevant to FNI and, in addition, some common approaches to statistical inference used in FNI. Low–pass filtering in relation to functional–anatomical variability and some effects of filtering on signal detection of interest to FNI are discussed. Also, some general aspects of hypothesis testing and statistical inference are discussed. This includes the need for characterizing the signal in data when the null hypothesis is rejected, the problem of multiple comparisons that is central to FNI data analysis, omnibus tests and some issues related to statistical power in the context of FNI. In turn, random field, scale space, non–parametric and Monte Carlo approaches are reviewed, representing the most common approaches to statistical inference used in FNI. Complementary to these issues an overview and discussion of non–inferential descriptive methods, common statistical models and the problem of model selection is given in a companion paper. In general, model selection is an important prelude to subsequent statistical inference. The emphasis in both papers is on the assumptions and inherent limitations of the methods presented. Most of the methods described here generally serve their purposes well when the inherent assumptions and limitations are taken into account. Significant differences in results between different methods are most apparent in extreme parameter ranges, for example at low effective degrees of freedom or at small spatial autocorrelation. In such situations or in situations when assumptions and approximations are seriously violated it is of central importance to choose the most suitable method in order to obtain valid results. | Audiovisual (AV) speech integration is often studied using the McGurk effect, where the combination of specific incongruent auditory and visual speech cues produces the perception of a third illusory speech percept. Recently, several studies have implicated the posterior superior temporal sulcus (pSTS) in the McGurk effect; however, the exact roles of the pSTS and other brain areas in “correcting” differing AV sensory inputs remain unclear. Using functional magnetic resonance imaging (fMRI) in ten participants, we aimed to isolate brain areas specifically involved in processing congruent AV speech and the McGurk effect. Speech stimuli were composed of sounds and/or videos of consonant-vowel tokens resulting in four stimulus classes: congruent AV speech (AVCong), incongruent AV speech resulting in the McGurk effect (AVMcGurk), acoustic-only speech (AO), and visual-only speech (VO). In group- and single-subject-analyses, left pSTS exhibited significantly greater fMRI signal for congruent AV speech (i.e., AVCong trials) than for both AO and VO trials. Right superior temporal gyrus, medial prefrontal cortex, and cerebellum were also identified. For McGurk speech (i.e., AVMcGurk trials), two clusters in the left posterior superior temporal gyrus (pSTG), just posterior to Heschl’s gyrus or on its border, exhibited greater fMRI signal than both AO and VO trials. We propose that while some brain areas, such as left pSTS, may be more critical for the integration of AV speech, other areas, such as left pSTG, may generate the “corrected” or merged percept arising from conflicting auditory and visual cues (i.e., as in the McGurk effect). These findings are consistent with the concept that posterior superior temporal areas represent part of a “dorsal auditory stream”, which is involved in multisensory integration, sensorimotor control, and optimal state estimation (Rauschecker and Scott, 2009). | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,559 |
Let $G$ be a finitely generated group acting properly by isometries and with a strongly contracting element on a geodesic metric space. Let $N$ be an infinite normal subgroup of $G$, and let $\delta_N$ and $\delta_G$ be the growth rates of $N$ and $G$ with respect to the pseudo-metric induced by the action. We prove that if $G$ has purely exponential growth with respect to the pseudo-metric then $\delta_N/\delta_G>1/2$. Our result applies to suitable actions of hyperbolic groups, right-angled Artin groups and other CAT(0) groups, mapping class groups, snowflake groups, small cancellation groups, etc. This extends Grigorchuk's original result on free groups with respect to a word metrics and a recent result of Jaerisch, Matsuzaki, and Yabuki on groups acting on hyperbolic spaces to a much wider class of groups acting on spaces that are not necessarily hyperbolic. | We prove a general version of the amenability conjecture in the unified setting of a Gromov hyperbolic group G acting properly cocompactly either on its Cayley graph, or on a CAT(-1)-space. Namely, for any subgroup H of G, we show that H is co-amenable in G if and only if their exponential growth rates (with respect to the prescribed action) coincide. For this, we prove a quantified, representation-theoretical version of Stadlbauer's amenability criterion for group extensions of a topologically transitive subshift of finite type, in terms of the spectral radii of the classical Ruelle transfer operator and its corresponding extension. As a consequence, we are able to show that, in our enlarged context, there is a gap between the exponential growth rate of a group with Kazhdan's property (T) and the ones of its infinite index subgroups. This also generalizes a well-known theorem of Corlette for lattices of the quaternionic hyperbolic space or the Cayley hyperbolic plane. | The effect of spatial separation on the ability of listeners to report keywords from two simultaneous talkers was examined. The talkers were presented with equal intensity at a clearly audible level, and were designed to have little spectral overlap in order to reduce energetic interference. The two talkers were presented in a virtual auditory environment with various angular separations around references of -45o, 0o, or 45o azimuth. In Experiment 1, the virtual space was created using head-related transfer functions (HRTFs) which contained natural energy variations as a function of location. In Experiment 2, these energy variations were removed and the virtual space was created using only interaural time differences (ITDs). Overall, performance did not vary dramatically but depended on spatial separation, reference direction, and type of simulation. Around the 0o reference azimuth, performance in the HRTF condition tended to first increase and then decrease with increasing separation. This effect was greatly reduced in the ITD condition and thus appears to be related primarily to energy variations at the two ears. For sources around the ± 45o reference azimuths, there was an advantage to separating the two sources in both HRTF and ITD conditions, suggesting that perceived spatial separation is advantageous in a divided attention task, at least for lateral sources. | eng_Latn | 10,560 |
This study investigated the effects of acoustic noise on the auditory nerve compound action potentials in response to electric pulse trains. Subjects were adult guinea pigs, implanted with a minimally invasive electrode to preserve acoustic sensitivity. Electrically evoked compound action potentials (ECAP) were recorded from the auditory nerve trunk in response to electric pulse trains both during and after the presentation of acoustic white noise. Simultaneously presented acoustic noise produced a decrease in ECAP amplitude. The effect of the acoustic masker on the electric probe was greatest at the onset of the acoustic stimulus and it was followed by a partial recovery of the ECAP amplitude. Following cessation of the acoustic noise, ECAP amplitude recovered over a period of approximately 100–200 ms. The effects of the acoustic noise were more prominent at lower electric pulse rates (interpulse intervals of 3 ms and higher). At higher pulse rates, the ECAP adaptation to the electric pulse train alone was larger and the acoustic noise, when presented, produced little additional effect. The observed effects of noise on ECAP were the greatest at high electric stimulus levels and, for a particular electric stimulus level, at high acoustic noise levels. | In order to investigate the temporal mechanisms of the auditory system, psychophysical forward masking experiments were conducted in cochlear implant users who had preserved acoustic hearing in the ipsilateral ear. This unique electric-acoustic stimulation (EAS) population allowed the measurement of threshold recovery functions for acoustic or electric probes in the presence of electric or acoustic maskers, respectively. In the electric masking experiment, the forward masked threshold elevation of acoustic probes was measured as a function of the time interval after the offset of the electric masker, i.e. the masker-to-probe interval (MPI). In the acoustic masking experiment, the forward masked threshold elevation of electric probe stimuli was investigated under the influence of a preceding acoustic masker. Since electric pulse trains directly stimulate the auditory nerve, this novel experimental setup allowed the acoustic adaptation properties (attributed to the physiology of the hair cells) to be differentiated from the subsequent processing by more central mechanisms along the auditory pathway. For instance, forward electric masking patterns should result more from the auditory-nerve response to electrical stimulation, while forward acoustic masking patterns should primarily be the result of the recovery from adaptation at the hair-cell neuron interface. Electric masking showed prolonged threshold elevation of acoustic probes, which depended significantly on the masker-to-probe interval. Additionally, threshold elevation was significantly dependent on the similarity between acoustic stimulus frequency and electric place frequency, the electric-acoustic frequency difference (EAFD). Acoustic masking showed a reduced, but statistically significant effect of electric threshold elevation, which did not significantly depend on MPI. Lastly, acoustic masking showed longer decay times than electric masking and a reduced dependency on EAFD. In conclusion, the forward masking patterns observed for combined electric-acoustic stimulation provide further insights into the temporal mechanisms of the auditory system. For instance, the asymmetry in the amount of threshold elevation, the dependency on EAFD and the time constants for the recovery functions of acoustic and electric masking all indicate that there must be several processes with different latencies (e.g. neural adaptation, depression of spontaneous activity, efferent systems) that are involved in forward masking recovery functions. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 10,561 |
Although it is widely held that colour and form are processed separately in early visual cortex, there is growing evidence that primary visual cortex (V1) may show some joint selectivity for orientation and colour. Colour is supplied to V1 via two very different pathways: the parvocellular pathway (which also supports detailed form processing) carries L–M (“red–green”) chromatic information, while a koniocellular pathway carries S-cone (“lilac–yellow”) information. Therefore on entering V1, S-cone information is segregated from the pathways carrying form information, while L–M information is not. Whether signals from neuronal populations in human V1 reflect combined orientation and S-cone information has not been systematically addressed. We used fMRI in combination with a multivariate data analysis technique to investigate whether BOLD signals recorded from V1 contain information that could directly discriminate between orientations based on different types of chromatic information. We found selectivity in V1 for L–M and luminance-defined orientation signals, and most interestingly, also for S-cone defined orientation. We also found similarly successful orientation discrimination for both colour dimensions in V2 and V3. These results imply that a proportion of cells throughout human visual cortex show joint sensitivity to both colour and orientation. We discuss also the potential role of feedback to V1 from higher visual areas. | When spatial attention is directed toward a particular stimulus, increased activity is commonly observed in corresponding locations of the visual cortex. Does this attentional increase in activity indicate improved processing of all features contained within the attended stimulus, or might spatial attention selectively enhance the features relevant to the observer9s task? We used fMRI decoding methods to measure the strength of orientation-selective activity patterns in the human visual cortex while subjects performed either an orientation or contrast discrimination task, involving one of two laterally presented gratings. Greater overall BOLD activation with spatial attention was observed in visual cortical areas V1–V4 for both tasks. However, multivariate pattern analysis revealed that orientation-selective responses were enhanced by attention only when orientation was the task-relevant feature and not when the contrast of the grating had to be attended. In a second experiment, observers discriminated the orientation or color of a specific lateral grating. Here, orientation-selective responses were enhanced in both tasks, but color-selective responses were enhanced only when color was task relevant. In both experiments, task-specific enhancement of feature-selective activity was not confined to the attended stimulus location but instead spread to other locations in the visual field, suggesting the concurrent involvement of a global feature-based attentional mechanism. These results suggest that attention can be remarkably selective in its ability to enhance particular task-relevant features and further reveal that increases in overall BOLD amplitude are not necessarily accompanied by improved processing of stimulus information. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,562 |
In our empirical data comprising of single-unit and LFP recordings in macaque area V1 and source reconstructed human MEG localized to visual cortex we have observed a robust increase in gamma oscillation frequency with increasing luminance contrast. In addition, at high grating contrasts, a robust decay in gamma power was observed in the LFP [1] but not the MEG. These phenomena are key to understanding the functional role of network frequencies and for investigating the stability of gamma oscillations at both local and macroscopic levels. However, even at the most basic level of spatially- undifferentiated neuronal models, it is not fully understood how excitatory (E) and inhibitory (I) neurons interact to generate the observed network gamma oscillations in the macaque single-unit and LFP data. For example we could obtain the frequency shift and power decay in a network where the rhythm is produced by excitatory neurons that fired more frequently than inhibitory neurons, and in another more neurophysiologically plausible network composed of excitatory neurons showing sparse firing [2,3] and inhibitory neurons showing faster firing [4]. Moreover, it is unknown how increasing excitatory afferent drive (of which luminance contrast is a proxy) modulates the interactions between E and I populations (as well as interactions within each population) to account for changes in frequency and power. We aimed to replicate the empirical data from macaque visual cortex and to further investigate the stability of the observed gamma oscillation. Here, we present an undifferentiated V1 network PING model, with realistic neuronal features as determined and validated from the analysis of a large number of V1 neurons obtained in 3 rhesus monkeys. The model when perturbed by increasing afferent input, exhibits the core characteristics of the empirical data, that is, (1) a monotonic increase in LFP frequency, (2) a non-monotonic LFP power modulation with decay at high inputs, (3) a largely non-saturating increase in average unit firing rate. In addition, the model exhibits realistic single unit behavior across a range of inputs. In terms of the frequency shift, we have observed remarkable scaling behaviour: while the frequency of oscillations changes dramatically with input, the absolute average phase at which inhibitory and excitatory neurons fire in each oscillation cycle and the average relative phase to each other remain constant. This scaling may on one hand underlie the stability of the gamma oscillation locally and on other hand facilitate communication through coherence in the gamma range [5] across varying stimulus conditions, by preserving the timing and relative ordering of population firing irrespective of the oscillation frequency [6]. Our results suggest that the observed power decline results from a primary (functional) decoupling among inhibitory neurons. Further analysis highlighted that the functional decoupling is related to the balance of inhibition/excitation. In further steps, we intend to test these predictions in the empirical data, and then proceed to a differentiated V1 columnar model to investigate the divergences between human MEG and macaque LFP/spiking responses. | Fine-scale temporal organization of cortical activity in the gamma range (∼25–80Hz) may play a significant role in information processing, for example by neural grouping (‘binding’) and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency codes or slower oscillation phase codes, may resolve conflicting experimental observations on gamma phase coding. Our modeling results offer clear testable experimental predictions. We conclude that input-dependency of gamma frequencies could be essential rather than detrimental for meaningful gamma-mediated temporal organization of cortical activity. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,563 |
A body orientation with the dorsal side up is usually maintained by lampreys during locomotion. Of crucial importance for this is the vestibular-driven control system. A visual input can affect the body orientation: illumination of one eye during swimming evokes roll tilt towards the source of light. The aim of the present study was to investigate the interaction of visual and vestibular inputs in reticulospinal (RS) neurons of the brainstem. The RS system is the main descending system transmitting information from the brainstem to the spinal cord. The response of neurons in the middle rhombencephalic reticular nucleus to a unilateral nonpatterned optic input was investigated, as well as the influence of this input on the response of RS neurons to vestibular stimulation (roll tilt). Experiments were carried out on a brainstem preparation with intact labyrinths and, in some cases, intact eyes. Illumination of one eye or electrical stimulation of the optic nerve (10 Hz) resulted in an activation of RS neurons preferentially on the ipsilateral side of the brainstem. The same result was obtained after ablation of the optic tectum, demonstrating that there are asymmetrical visual projections to the lower brainstem which do not involve the tectum. Stimulation of the optic nerve strongly affected the vestibular response in RS neurons. As a rule RS neurons are silent at the normal (dorsal-side-up) orientation of the brainstem and become active with contralateral roll tilt. During continuous optic nerve stimulation, however, the RS neurons on the side of stimulation fire during normal orientation of the brainstem, and the response to contralateral roll tilt increases considerably in many neurons. The effects of the optic input in contralateral RS neurons were less consistent. Any asymmetry in the signals transmitted to the spinal cord by the two (left and right) sub-populations of RS neurons can be expected to evoke a correcting motor response aimed at turning the body around its longitudinal axis to a position at which the symmetry between left and right RS neurons is restored. Normally, the symmetry will occur when the dorsal side is upwards, but with a unilateral visual input it will occur instead at some degree of ipsilateral roll. | 1. Application of D-glutamate to the isolated spinal cord of the lamprey produces phasic activity in ventral roots, which is similar to that of the muscles of the intact swimming animal (5,18). Therefore, the isolated spinal cord may be used as a convenient model for the investigation of the generation of locomotor rhythms in a vertebrate. 2. Almost all slow muscle fibers exhibited excitatory junctional potentials (EJPs) during swimming activity. The number of EJPs per cycle increased with the intensity of ventral root (VR) bursting. Few twitch fibers were active, and these fired action potentials only during high intensities of VR bursts. 3. As was found by Russell and Wallen (25), myotomal motoneurons had oscillating membrane potentials during fictive swimming which, on the average, reached a peak depolarization in the middle of the VR burst (phi = 0.21 +/- 0.05; phi = 0 is defined as the onset of the VR burst, and the duration of the cycle is set equal to 1). Membrane potential oscillations in fin motoneurons were antiphasic to those of nearby myotomal motoneurons (peak depolarization phi = 0.68 +/- 0.05). 4. Lateral interneurons had oscillating membrane potentials in synchrony with those of myotomal motoneurons (peak depolarization phi = 0.21 +/- 0.10). Interneurons with axons projecting contralaterally and caudally (CC interneurons) had oscillating membrane potentials that peaked significantly earlier in the cycle (peak depolarization phi = 0.06 +/- 0.12). 5. Edge cells were only weakly modulated during fictive swimming. Their peak depolarizations occurred near the end of the VR burst (phi = 0.33 +/- 0.10). Most giant interneurons were not phasically modulated during fictive swimming. 6. Repetitive intracellular stimulation of Muller cells during fictive swimming generally evoked an increased burst intensity in ipsilateral VRs and a decreased burst intensity in contralateral VRs. The cells M3, B1, and B2 also produced increases or decreases in the frequency of VR bursts. Repetitive intracellular stimulation of sensory dorsal cells could also change the intensities and timing of VR bursts. 7. This study is an initial survey of lamprey spinal interneurons that participate in swimming activity. Lateral interneurons and CC interneurons are active during fictive swimming and probably help coordinate the undulations of the body, but their roles in pattern generation are not known. The central pattern generator is subject to modification by descending and sensory inputs. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,564 |
With the advent of sophisticated acquisition and analysis techniques, decoding the contents of someone's experience has become a reality. We propose a straightforward linear Gaussian approach, where decoding relies on the inversion of properly regularized encoding models, which can still be solved analytically. In order to test our approach we acquired functional magnetic resonance imaging data under a rapid event-related design in which subjects were presented with handwritten characters. Our approach is shown to yield state-of-the-art reconstructions of perceived characters as estimated from BOLD responses. This even holds for previously unseen characters. We propose that this framework serves as a baseline with which to compare more sophisticated models for which analytical inversion is infeasible. | ▪ It has long been assumed that sensory neurons are adapted, through both evolutionary and developmental processes, to the statistical properties of the signals to which they are exposed. Attneave (1954), Barlow (1961) proposed that information theory could provide a link between environmental statistics and neural responses through the concept of coding efficiency. Recent developments in statistical modeling, along with powerful computational tools, have enabled researchers to study more sophisticated statistical models for visual images, to validate these models empirically against large sets of data, and to begin experimentally testing the efficient coding hypothesis for both individual neurons and populations of neurons. | This paper has been withdrawn by the author due to a crucial mistakes. | eng_Latn | 10,565 |
In this paper, an improved and much stronger RNH-QL method based on RBF network and heuristic Q-learning was put forward for route searching in a larger state space. Firstly, it solves the problem of inefficiency of reinforcement learning if a given problem’s state space is increased and there is a lack of prior information on the environment. Secondly, RBF network as weight updating rule, reward shaping can give an additional feedback to the agent in some intermediate states, which will help to guide the agent towards the goal state in a more controlled fashion. Meanwhile, with the process of Q-learning, it is accessible to the underlying dynamic knowledge, instead of the need of background knowledge of an upper level RBF network. Thirdly, it improves the learning efficiency by incorporating the greedy exploitation strategy to train the neural network, which has been testified by the experimental results. | Walter J. Freeman was a giant of the field of neuroscience whose visionary work contributed various experimental and theoretical breakthroughs to brain research in the past 60 years. He has pioneered a number of Electroencephalogram and Electrocorticogram tools and approaches that shaped the field, while “Freeman Neurodynamics” is a theoretical concept that is widely known, used, and respected among neuroscientists all over the world. His recent death is a profound loss to neuroscience and biomedical engineering. Many of his revolutionary ideas on brain dynamics have been ahead of their time by decades. We summarize his following groundbreaking achievements: (1) Mass Action in the Nervous System, from microscopic (single cell) recordings, through mesoscopic populations, to large-scale collective brain patterns underlying cognition; (2) Freeman–Kachalsky model of multi-scale, modular brain dynamics; (3) cinematic theory of cognitive dynamics; (4) phase transitions in cortical dynamics modeled with random graphs and quantum field theory; (5) philosophical aspects of intentionality, consciousness, and the unity of brain–mind–body. His work has been admired by many of his neuroscientist colleagues and followers. At the same time, his multidisciplinary approach combining advanced concepts of control theory and the mathematics of nonlinear systems and chaos, poses significant challenges to those who wish to thoroughly understand his message. The goal of this commemorative paper is to review key aspects of Freeman’s neurodynamics and to provide some handles to gain better understanding about Freeman’s extraordinary intellectual achievement. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,566 |
The ability to discriminate between two brief sounds having identical frequency components, but differing in the intensity of one or more of the components, is studied. The stimulus manipulations include randomizing the overall intensity of the sounds, varying the number and spacing of the components, and varying the interval of time between the sounds. The results from the experiment in which interstimulus interval is manipulated clearly support a profile analysis mechanism that computes two rough spectral analyses, stores a classification of these spectra in memory, and compares the two stores. This profile mechanism involves a simultaneous comparison of different components of the complex, some remote from the signal frequency, rather than a successive comparison of the difference in intensity at the signal frequency. The simultaneous comparison process is more sensitive when the profile is composed of many components spaced over a wide frequency range. | Processing mechanisms used for detection of tones in noise can be revealed by using reproducible noise maskers and analyzing the pattern of results across masker waveforms. This study reports detection of a 500-Hz tone in broadband reproducible noise by rabbits using a set of masker waveforms for which human results are available. An appetitive-reinforcement, operant-conditioning procedure with bias control was used. Both fixed-level and roving-level noises were used to explore the utility of energy-related cues for detection. An energy-based detection model was able to partially explain the fixed-level results across reproducible noise waveforms for both rabbit and human. A multiple-channel energy model was able to explain fixed-level results, as well as the robust performance observed with roving-level noises. Further analysis using the energy model indicated a difference between species: human detection was influenced most by the noise spectrum surrounding the tone frequency, whereas rabbit detection was influenced most by the noise spectrum at frequencies above that of the tone. In addition, a temporal envelope-based model predicted detection by humans as well as the single-channel energy model did, but the envelope-based model failed to predict detection by rabbits. This result indicates that the contributions of energy and temporal cues to auditory processing differ across species. Overall, these findings suggest that caution must be used when evaluating neural encoding mechanisms in one species on the basis of behavioral results in another. | A key competitive precondition for any organization involved in any of today's multinational businesses is speed and pace in implementing strategies. Although one's organization may offer superior products or services today, it may quickly lag behind its competitors if it is not adept at implementing critical decisions. | eng_Latn | 10,567 |
Ample data indicate that the gustatory cortex (GC) subserves the processing, encoding, and storage of taste information. To further elucidate the neural processes involved, we recorded multi-unit activity in the GC of the freely behaving rat as it became familiar with a novel tastant. Exposure to the tastant was performed over three 40- to 50-min sessions, 24 h apart. In each session, the tastant was presented repeatedly, 1 s at a time, with 10- to 12-s inter-trial intervals. The neural response to the tastant typically lasted 7 s. Our results show that the average neuronal response to the tastant increased as this tastant became familiar, but this increase was detected only during the last 5 s of the response. The increased response was not generalized to another tastant. Furthermore, our analysis suggests that specific neuronal populations subserve the processing of familiarity of specific tastants. The signature of familiarity was not detected in the course of the familiarization session, but only on t... | Frequency receptive fields (RFs) were determined before and after pairing iontophorectic administration of acetylcholine (ACh) with a repeated single-frequency stimulus in the auditory cortex of barbiturate-anesthesized cats. In 58% of the cells, the paired ACh + tone treatment produced subsequent alterations of frequency RFs. In half of these cases, the RF modifications were highly specific to the frequency that had been paired with ACh. Atropine antagoized the frequency-effects of ACh, suggesting that they were mediated via muscarinic cholinergic receptors. | Highly familiar letter sequences (English words) in noncued portions of a tachistoscopic display were shown to substantially reduce accuracy of partial report. These findings suggest that in addition to facilitating character scanning, familiarity may operate in automatically directing attentional resources to a particular spatial region of a display. Such attentional capture may be disruptive if the material to be reported is presented at another location. Language: en | eng_Latn | 10,568 |
There is strong evidence for dissociable "what" and "where" pathways in the auditory system, but considerable debate remains regarding the functional role of these pathways. The sensory-motor account of spatial processing posits that the dorsal brain regions (e.g., inferior parietal lobule, IPL) mediate sensory-motor integration required during "where" responding. An alternative account suggests that the IPL plays an important role in monitoring sound location. To test these two models, we used a mixed-block and event-related functional magnetic resonance imaging (fMRI) design in which participants responded to occasional repetitions in either sound location ("where" task) or semantic category ("what" task). The fMRI data were analyzed with the general linear model using separate regressors for representing sustained and transient activity in both listening conditions. This analysis revealed more sustained activity in right dorsal brain regions, including the IPL and superior frontal sulcus, during the location than during the category task, after accounting for transient activity related to target detection and the motor response. Conversely, we found greater sustained activity in the left superior temporal gyrus and left inferior frontal gyrus during the category task compared to the location task. Transient target-related activity in both tasks was associated with enhanced signal in the left pre- and postcentral gyrus, prefrontal cortex and bilateral IPL. These results suggest dual roles for the right IPL in auditory working memory--one involved in monitoring and updating sound location independent of motor responding, and another that underlies the integration of sensory and motor functions. | The neuronal response patterns that are required for an adequate behavioural reaction to subjectively relevant changes in the environment are commonly studied by means of oddball paradigms, in which occasional ‘target’ stimuli have to be detected in a train of frequent ‘non-target’ stimuli. The detection of such task-relevant stimuli is accompanied by a parietocentral positive component of the event-related potential, the P300. We performed EEG recordings of visual and auditory event-related potentials and functional magnetic resonance imaging (fMRI) when healthy subjects performed an oddball task. Significant increases in fMRI signal for target versus non-target conditions were observed in the supramarginal gyrus, frontal operculum and insular cortex bilaterally, and in further circumscribed parietal and frontal regions. These effects were consistent over various stimulation and response modalities and can be regarded as specific for target detection in both the auditory and the visual modality. These results therefore contribute to the understanding of the target detection network in human cerebral cortex and impose constraints on attempts at localizing the neuronal P300 generator. This is of importance both from a neurobiological perspective and because of the widespread application of the physiological correlates of target detection in clinical P300 studies. | Blunt trauma abdomen rarely leads to gastrointestinal injury in children and isolated gastric rupture is even rarer presentation. We are reporting a case of isolated gastric rupture after fall from height in a three year old male child. | eng_Latn | 10,569 |
The brain encodes information by neural spiking activities, which can be described by time series data as spike counts. Latent Variable Models (LVMs) are widely used to study the unknown factors (i.e. the latent states) that are dependent in a network structure to modulate neural spiking activities. Yet, challenges in performing experiments to record on neuronal level commonly results in relatively short and noisy spike count data, which is insufficient to derive latent network structure by existing LVMs. Specifically, it is difficult to set the number of latent states. A small number of latent states may not be able to model the complexities of underlying systems, while a large number of latent states can lead to overfitting. Therefore, based on a specific LVMs called Linear Dynamical System (LDS), we propose a Reduced-Rank Linear Dynamical System (RRLDS) to estimate latent states and retrieve an optimal latent network structure from short, noisy spike count data. This framework estimates the model using Laplace approximation. To further handle count-valued data, we introduce the dispersion-adaptive distribution to accommodate over-/ equal-/ and under-dispersion nature of such data. Results on both simulated and experimental data demonstrate our model can robustly learn latent space from short-length, noisy, count-valued data and significantly improve the prediction performance over the state-of-the-art methods. | At present, the prime methodology for studying neuronal circuit-connectivity, physiology and pathology under in vitro or in vivo conditions is by using substrate-integrated microelectrode arrays. Although this methodology permits simultaneous, cell-non-invasive, long-term recordings of extracellular field potentials generated by action potentials, it is 'blind' to subthreshold synaptic potentials generated by single cells. On the other hand, intracellular recordings of the full electrophysiological repertoire (subthreshold synaptic potentials, membrane oscillations and action potentials) are, at present, obtained only by sharp or patch microelectrodes. These, however, are limited to single cells at a time and for short durations. Recently a number of laboratories began to merge the advantages of extracellular microelectrode arrays and intracellular microelectrodes. This Review describes the novel approaches, identifying their strengths and limitations from the point of view of the end users--with the intention to help steer the bioengineering efforts towards the needs of brain-circuit research. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,570 |
This study examined the speech perception performance of 71 postlingually deafened adults implanted with the CLARION® Multi-Strategy™ Cochlear Implant. After 3 months of implant use, one third of the patients (n = 23) preferred to use the Simultaneous Analog Stimulation (SAS) strategy, and two thirds of them (n = 48) chose to use the Continuous Interleaved Sampler (CIS) strategy. The mean CID sentence scores were similar for the SAS and CIS user groups at the 3-month postoperative interval. In contrast, the mean CNC word score of the SAS users was significantly higher than the mean score of the CIS users after 3 months of implant experience. Patients who preferred to use SAS demonstrated significantly shorter duration of deafness at time of implantation than did the CIS users, whereas the CIS users demonstrated significantly higher preoperative sentence recognition scores than the SAS users. The results suggested that access to a preferred processing strategy improved the overall group performance of post... | Patterns of threshold distributions for single-cycle sinusoidal electrical stimulation and single pulse electrical stimulation were compared in primary auditory cortex of the adult cat. Furthermore, the effects of auditory deprivation on these distributions were evaluated and compared across three groups of adult cats. Threshold distributions for single and multiple unit responses from the middle cortical layers were obtained on the ectosylvian gyrus in an acutely implanted animal; 2 wk after deafening and implantation (short-term group); and neonatally deafened animals implanted following 2–5 yr of deafness (long-term group). For all three cases, we observed similar patterns of circumscribed regions of low response thresholds in the region of primary auditory cortex (AI). A dorsal and a ventral region of low response thresholds were found separated by a narrow, anterior-posterior strip of elevated thresholds. The ventral low-threshold regions in the short-term group were cochleotopically arranged. By contrast, the dorsal region in the short-term animals and both low-threshold regions in long-term deafened animals maintained only weak cochleotopicity. Analysis of the spatial extent of the low-threshold regions revealed that the activated area for sinusoidal stimulation was smaller and more circumscribed than for pulsatile stimulation for both dorsal and ventral AI. The width of the high-threshold ridge that separated the dorsal and ventral low-threshold regions was greater for sinusoidal stimulation. Sinusoidal and pulsatile threshold behavior differed significantly for electrode configurations with low and high minimum thresholds. Differences in threshold behavior and cortical response distributions between the sinusoidal and pulsatile stimulation suggest that stimulus shape plays a significant role in the activation of cortical activity. Differences in the activation pattern for short-term and long-term deafness reflect deafness-induced reorganizational changes based on factors such as differences in excitatory and inhibitory balance that are affected by the stimulation parameters. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,571 |
Twelve Ss made magnitude estimations of the loudness of each one of a sequence of pure tones according to the rule R(N) = R(N - 1) · [S(N)/S(N - 1)], where R(N) is the response on Trial N, R(N - 1) is the response on Trial N - 1, and S(N)/S(N - 1) is the judged ratio of the “loudness” of the pure tone presented on Trial N to that of the pure tone presented on Trial N - 1. It was found that these magnitude estimations were assimilated toward the immediately preceding stimuli as far as five trials back in the sequence of stimuli. In addition, ratio judgments were consistently asymmetric and the data displayed a form of “time order error.” In all cases, there are similar effects displayed in category judgment data. These and other data imply that at least some kinds of magnitude estimations may involve a judgment of the “difference” or “distance” between pairs of stimuli as a first step in the production of the response required by the judgment situation. | Three models of sequential effects in psychophysica l tasks are defined and experimental results described. These appear most consistent with a model in which the momentary value of the criterion is modified by memory traces, an independent trace being retained for each relevant past event. On this basis, a theory of criterion setting is developed: A long-term process determines an initial value for the criterion, and two short-term processes adjust the criterion (a) to match current changes in the expected probabilities of signals and (b) to maximize the information transmitted by the subject's responses. The theory is applied to results in the literature. Although signal detection theory (SDT; Green & Swets, 1966), which is now widely applied, includes the hypothesis of a decision criterion and puts forward normative prescriptions for its value, the problem of how a subject maintains his criterion at the appropriate value and adjusts that value to take account of relevant intercurrent events has largely been ignored. It is regrettable that criterion setting should generally be treated as a given but unexamined fact, because its proper understanding may clarify important psychological aspects of decision in all areas and may help to explain some still unresolved problems such as the causation of sequential effects. The object of the present article is to present a theory of criterion setting developed by the first author. As this theory arose from a consideration of some features of sequential dependencies, we begin with a brief discussion of the latter. It is a familiar but still unexplained observation that the outcomes of successive psychophysical decisions are related (Verplanck, | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,572 |
Effect of Fractal Tones on the Improvement of Tinnitus Handicap Inventory Functional Scores among Chronic Tinnitus Patients: An Open-label Pilot Study | Strategies for the Selection of Music in the Short-term Management of Mild Tinnitus | Floating frogs sound larger: environmental constraints on signal production drives call frequency changes | eng_Latn | 10,573 |
Auditory trace fear conditioning requires perirhinal cortex | Graded persistent activity in entorhinal cortex neurons | Exogenous growth factors do not affect the development of individually cultured murine embryos | eng_Latn | 10,574 |
Theta EEG dynamics of the error-related negativity | Electrophysiological correlates of feedback processing in subarachnoid hemorrhage patients. | Every Graph With A Positive Cheeger Constant Contains A Tree With A Positive Cheeger Constant | eng_Latn | 10,575 |
Optimized inter-stimulus interval (ISI) and content design for evoking better visual evoked potential (VEP) in brain-computer interface applications | EFFECT OF DIFFERENT INTER-STIMULUS INTERVALS (ISI) ON CORTICAL AUDITORY EVOKED POTENTIAL IN NORMAL HEARING ADULTS: A PRELIMINARY FINDING | Oral spray wintertime vitamin D3 supplementation has no impact on inflammation in Gaelic footballers | eng_Latn | 10,576 |
Visual Cortical Evoked Potentials in Alcoholics and Normals Maintained on Lithium Carbonate: Augmentation and Reduction Phenomena | Loudness Dependence of Auditory Evoked Potentials as Indicator of Central Serotonergic Neurotransmission: Simultaneous Electrophysiological Recordings and In Vivo Microdialysis in the Rat Primary Auditory Cortex | Porin channels in intact cells of Escherichia coli are not affected by Donnan potentials across the outer membrane. | eng_Latn | 10,577 |
Robust stabilization control of bifurcations in Hodgkin-Huxley model with aid of unscented Kalman filter | Robust closed-loop control of spike-and-wave discharges in a thalamocortical computational model of absence epilepsy | Ca2+ Extrusion by NCX Is Compromised in Olfactory Sensory Neurons of OMP−/− Mice | eng_Latn | 10,578 |
Stimulus-related changes in cerebral blood oxygenation were measured using high-resolution functional magnetic resonance imaging sequentially covering visual occipital areas in contiguous sections. During dynamic imaging, healthy subjects silently viewed pseudowords, single false fonts, or length-matched strings of the same false fonts. The paradigm consisted of a sixfold alternation of an activation and a control task. With pseudowords as activation vs single false fonts as control, responses were seen mainly in medial occipital cortex. These responses disappeared when pseudowords were alternated with false font strings as the control and reappeared when false font strings instead of pseudowords served as activation and were alternated with single false fonts. The string-length contrast alone, therefore, is sufficient to account for the activation pattern observed in medial visual cortex when word-like stimuli are contrasted with single characters. | Although investigations into the functional and anatomical organization of language within the human brain began centuries ago, it is recent advanced imaging techniques including functional magnetic resonance imaging and diffusion tensor imaging that have helped propel our understanding forward at an unprecedented rate. Important cortical brain regions and white matter tracts in language processing subsystems including semantic, phonological, and orthographic functions have been identified. An understanding of functional and dysfunctional language anatomy is critical for practicing radiologists. This knowledge can be applied to routine neuroimaging examinations as well as to more advanced examinations such as presurgical brain mapping. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,579 |
Neocortical layer 5 intrinsically bursting (IB) pyramidal neurons were simulated using compartment model methods. Morphological data as well as target neurophysiological responses were taken from a series of published studies on the same set of rat visual cortex pyramidal neurons (Mason, A. and Larkman, A. J., 1990. J. Neurosci. 9,1440-1447; Larkman, A. J. 1991. J. Comp. Neurol. 306, 307-319). A dendritic distribution of ion channels was found that reproduced the range of in vitro responses of layer 5 IB pyramidal neurons, including the transition from repetitive bursting to the burst/tonic spiking mode seen in these neurons as input magnitude increases. In light of available data, the simulation results suggest that in these neurons bursts are driven by an inward flow of current during a high threshold Ca2+ spike extending throughout both the basal and apical dendritic branches. | The Electroencephalogram (EEG) is an important clinical and research tool in neurophysiology. With the advent of recording techniques, new evidence is emerging on the neuronal populations and wiring in the neocortex. A main challenge is to relate the EEG generation mechanisms to the underlying circuitry of the neocortex. In this paper, we look at the principal intrinsic properties of neocortical cells in layer 5 and their network behavior in simplified simulation models to explain the emergence of several important EEG phenomena such as the alpha rhythms, slow-wave sleep oscillations, and a form of cortical seizure. The models also predict the ability of layer 5 cells to produce a resonance-like neuronal recruitment known as the augmenting response. While previous models point to deeper brain structures, such as the thalamus, as the origin of many EEG rhythms (spindles), the current model suggests that the cortical circuitry itself has intrinsic oscillatory dynamics which could account for a wide variety of EEG phenomena. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 10,580 |
In this paper, we integrate impulsive control and adaptive control methods, based on the stability theory of impulsive differential equations, generalized projective synchronization between the general complex dynamical networks with time delay is investigated. A nonlinear controller, updating laws and a linear impulsive controller are proposed. An adaptive-impulsive generalized projective synchronization criterion of network with time delay is established. Moreover, the complex network with time delay consisting of energy resource system is used as a numerical example. Generalized projective synchronization between two energy resource complex networks with time delay is achieved. This study will be instructive for the demand-supply of energy resource in some regions of China. | The ultimate state of projective synchronization is hardly predictable. A control algorithm is thus proposed to manipulate the synchronization in arbitrary dimension. The control law derived from the Lyapunov stability theory with the aid of slack variables is effective to any initial conditions. The method allows us to amplify and reduce the synchronized dynamics in any desired scale with tiny control inputs. Applications are illustrated for seven- and ten-dimensional chaotic systems. | Several sufficient conditions which guarantee stability of linear time-delay systems are derived. Each of these results is expressed by a succinct scalar inequality and corresponds to a certain extent to the tradeoff between simplicity and sharpness. | eng_Latn | 10,581 |
The auditory brainstem response (ABR) is a series of volume conducted potentials that can be recorded from the scalp within 10 ms following auditory stimulation. Differences between ABRs evoked with binaural stimulation and those constructed by summing equivalent numbers of monaural stimulation to each ear indicate the presence of binaural interaction for some ABR potentials but not for others. In the present study, ABR binaural interactions were studied in both cats and kittens. Binaural interactions were not seen for waves 1-3 but were present at the latencies of waves 4, 5 and, in most cases, 6. The sound intensities used were selected to insure that acoustic cross-over, i.e. sound presented monaurally to one ear stimulating the other, did not influence binaural interaction effects. Experiments with cats that had been monaurally deafened confirmed that the effects observed were not due to acoustic cross-over. Systematic manipulation of stimulus rate and intensity produced marked changes in the level of binaural interaction. Increases in stimulation rate from 10 to 100 clicks/s reduced binaural interaction for wave 4 and reversed the direction of binaural interaction for wave 5. Wave 6 was not generally present at rates above 10 clicks/s. Reduction of stimulus intensity reduced binaural interaction for wave 4. Binaural interaction effects were at adult levels in kittens of 20 days for waves 4 and 5. Wave 6 was not present until 30 days of age. These data suggest a possible model of the physiological processes producing binaural interaction which is based on occlusion as seen in other areas of the nervous system. In such a model, convergent input becomes more important in driving the generators of some ABR potentials when the system is stressed (as, for example, by increased stimulus rate), than it is when the system is not stressed. | The auditory brainstem response (ABR) is a sound-evoked noninvasively measured electrical potential representing the sum of neuronal activity in the auditory brainstem and midbrain. ABR peak amplitudes and latencies are widely used in human and animal auditory research and for clinical screening. The binaural interaction component (BIC) of the ABR stands for the difference between the sum of the monaural ABRs and the ABR obtained with binaural stimulation. The BIC comprises a series of distinct waves, the largest of which (DN1) has been used for evaluating binaural hearing in both normal hearing and hearing-impaired listeners. Based on data from animal and human studies, the authors discuss the possible anatomical and physiological bases of the BIC (DN1 in particular). The effects of electrode placement and stimulus characteristics on the binaurally evoked ABR are evaluated. The authors review how interaural time and intensity differences affect the BIC and, analyzing these dependencies, draw conclusion about the mechanism underlying the generation of the BIC. Finally, the utility of the BIC for clinical diagnoses are summarized. | There have been many “end of affair” comments on the Anglo-American special relationship (AASR) in the post-Cold War era. Notwithstanding this, the AASR has managed to persist without losing its vitality up to the present. This article seeks to explain the persistence of the AASR from the perspective of collective identity. It argues that a strong Anglo-American collective identity has been an indispensable positive contributor to the persistence of the AASR after the end of the Cold War. The strong Anglo-American collective identity facilitates Anglo-American common threat perceptions, solidifies embedded trust between the UK and the USA, and prescribes norms of appropriate behaviour for these two countries. | eng_Latn | 10,582 |
This paper discusses synaptic inhibition of one pacemaker neuron by another, using data from living synapses. Spike discharges were assimilated to point processes. Inhibitory rate scale and behavior form. (i) Forms (p:q locked and others) with similar prevalent spectral components assembled monotonically with p:q. Between different lockings, intermittent, messy and other intermittent forms staggered characteristically; hoppings were interspersed. (ii) Locked, intermittent and messy forms occupied about 1/3 each of the rate scale. Individually, the 1:1, 2:1 and 1:2 locked domains were the widest, and seemed continuous; individual intermittent and messy domains were very narrow. Step-like inhibitory transients induced abrupt postsynaptic changes opposing them, which over- or under-shot and slowly returned in either orderly or complicated (chaotic?) ways to steady states. Input-output relations around inhibitory trains resembled those of first-order lead-lag systems distorted by asymmetric sensitivity to change and saturation. Postsynaptic natural discharges separated into "slow" less variable, and "fast" more variable categories with somewhat different inhibited behaviors. Formal modeling is introduced by summarizing comparable models, the data-assumption discrepancies, and reasonable conjectures as to eventual models. | It has been known for 30 years that the output of a repetitively firing neuron or pacemaker can be synchronized (locked) to regularly spaced inhibitory or excitatory postsynaptic input potentials. Conditions for stable locking have been determined mathematically, demonstrated in computer simulation, and locking has been observed in vivo. We have developed a neural spike generator circuit model which exhibits stable locking to externally derived simulated inhibitory or excitatory post-synaptic inputs. Conditions for stable 1 : 1 lock, in which pacemaker output frequency matches that of the periodic input, are derived. These take the form of expressions for stable delay and convergence factor which incorporate known or measurable parameters of the circuit model. The expressions have been evaluated and shown to compare satisfactorily with experimental observations of locking by our circuit model. | Distillation at an infinite reflux ratio in combination with an infinite number of trays has been investigated. | eng_Latn | 10,583 |
Objectives:Current cochlear implant (CI) devices are limited in providing voice pitch information that is critical for listeners' recognition of prosodic contrasts of speech (e.g., intonation and lexical tones). As a result, mastery of the production and perception of such speech contrasts can be ve | Four-band and single-band noise-excited vocoders were used in acoustic simulations to investigate spectral and temporal cues to melodic pitch in the output of a cochlear implant speech processor. Noise carriers were modulated by amplitude envelopes extracted by half-wave rectification and low-pass filtering at 32 or 400 Hz. The four-band, but not the single-band processors, may preserve spectral correlates of fundamental frequency (F0). Envelope smoothing at 400 Hz preserves temporal correlates of F0, which are eliminated with 32-Hz smoothing. Inputs to the processors were sawtooth frequency glides, in which spectral variation is completely determined by F0, or synthetic diphthongal vowel glides, whose spectral shape is dominated by varying formant resonances. Normal listeners labeled the direction of pitch movement of the processed stimuli. For processed sawtooth waves, purely temporal cues led to decreasing performance with increasing F0. With purely spectral cues, performance was above chance despite the limited spectral resolution of the processors. For processed diphthongs, performance with purely spectral cues was at chance, showing that spectral envelope changes due to formant movement obscured spectral cues to F0. Performance with temporal cues was poorer for diphthongs than for sawtooths, with very limited discrimination at higher F0. These data suggest that, for speech signals through a typical cochlear implant processor, spectral cues to pitch are likely to have limited utility, while temporal envelope cues may be useful only at low F0. | It has long been known that several popular default and conditional logics exactly describe infinitesimal probability constructs which betoken virtual certainty regarding the truth of one sentence if some other sentence is true. That the rules for default inference also describe a scheme of approximate inference for all positive-valued conditional probabilities has also long been known. More recently, a class of standard probability measures has been found whose expression of more likely than not is exactly described by default rules. This class can be extended by straightforward algebra so that the range of confidence levels expressed by standard probability distributions which are exactly described by the rules is as complete as for the approximate methods. | eng_Latn | 10,584 |
The clinical diagnosis can detect the presence of brain disease once significant neuronal disruption has occurred. Early clinical detection of neuropsychological disorder lacks the unification standards. The aim of this study was to describe the neural mechanism of audiovisual interaction in healthy subjects by combining behavior-based methods (neuropsychological testing) and event-related potentials (ERP), and to provide a neural mechanism for early clinical detection. We designed the stimulus onset asynchrony (SOA) between sound and visual (−400 ms, −150 ms, 0 ms, 150 ms, 400 ms, visual only and sound only, each with equal probability, randomly in each trial), so that the subject could not find the cognitive rules connecting the two stimuli. The behavioral results showed that the responses to temporal congruency audiovisual (AV) stimuli were faster than those to unimodal visual(V) stimuli. The ERPs results showed audiovisual interaction elicited by irrelevant auditory(A) stimuli in a visual attention task. This interaction occurred at late stage around 220∼240ms and 340∼380ms. | The aim of this study was (1) to provide behavioral evidence for multimodal feature integration in an object recognition task in humans and (2) to characterize the processing stages and the neural structures where multisensory interactions take place. Event-related potentials (ERPs) were recorded from 30 scalp electrodes while subjects performed a forcedchoice reaction-time categorization task: At each trial, the subjects had to indicate which of two objects was presented by pressing one of two keys. The two objects were defined by auditory features alone, visual features alone, or the combination of auditory and visual features. Subjects were more accurate and rapid at identifying multimodal than unimodal objects. Spatiotemporal analysis of ERPs and scalp current densities revealed several auditory-visual interaction components temporally, spatially, and functionally distinct before 200 msec poststimulus. The effects observed were (1) in visual areas, new neural activities (as early as 40 msec poststimulus) and modu lation (amplitude decrease) of the N185 wave to unimodal visual stimulus, (2) in the auditory cortex, modulation (amplitude increase) of subcomponents of the unimodal auditory N1 wave around 90 to 110 msec, and (3) new neural activity over the right fronto-temporal area (140 to 165 msec).Furthermore, when the subjects were separated into two groups according to their dominant modality to perform the task in unimodal conditions (shortest reaction time criteria), the integration effects were found to be similar for the two groups over the nonspecific fronto-temporal areas, but they clearly differed in the sensory-specific cortices, affecting predominantly the sensory areas of the nondominant modality. Taken together, the results indicate that multisensory integration is mediated by flexible, highly adaptive physiological processes that can take place very early in the sensory processing chain and operate in both sensory-specific and nonspecific cortical structures in different ways. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 10,585 |
Due Due to extensive use of Carbon Fiber Reinforcement Polymer (CFRP) composite in various application such as aerospace, defence, automobile, sports etc. there is a challenge before the industry to deliver the best quality product. To improve the quality of the product there is a need for analysis to ensure the safety and dimensional stability during its application. The experimental approach can be used to ensure quality of product which requires huge amount of time and cost. To avoid this, as an alternative options analytical and numerical approach can be used for conducting analysis. In this paper, static structural analysis of the layered un-symmetric composite laminate under normal loads has been performed. Stresses and strains in every layer of the laminate has been calculated using analytical and Finite Element Analysis (FEA) models. For obtaining analytical results a MATLAB program is developed for ease of calculation of stresses and strains for any number of layers in the laminate. The MATLAB program is based on Classical Lamination Theory (CLT). FEA is performed using ANSYS APDL. The results obtained from FEA and analytical are compared and both the results are found in good agreement. The maximum difference is 0.37% at 45o layer in maximum shear stress in xy-plane. | The combination of materials to form a new material system with enhanced material properties is a well documented historical fact. For example, the ancient Jewish workers during their tenure under the Pharaohs used chopped straws in bricks as a means of enhancing their structural integrity. The Japanese Samurai warriors were known to use laminated metals in the forging of their swords to obtain desirable material properties. Even certain artisans from the Mediterranean and Far East used a form of composite technology in molding art works which were fabricated by layering cut paper in various sizes for producing desired shapes and contours. | In mammals, acoustic communication plays an important role during social behaviors. Despite their ethological relevance, the mechanisms by which the auditory cortex represents different communication call properties remain elusive. Recent studies have pointed out that communication-sound encoding could be based on discharge patterns of neuronal populations. Following this idea, we investigated whether the activity of local neuronal networks, such as those occurring within individual cortical columns, is sufficient for distinguishing between sounds that differed in their spectro-temporal properties. To accomplish this aim, we analyzed simple pure-tone and complex communication call elicited multi-unit activity (MUA) as well as local field potentials (LFP), and current source density (CSD) waveforms at the single-layer and columnar level from the primary auditory cortex of anesthetized Mongolian gerbils. Multi-dimensional scaling analysis was used to evaluate the degree of “call-specificity” in the evoked activity. The results showed that whole laminar profiles segregated 1.8-2.6 times better across calls than single-layer activity. Also, laminar LFP and CSD profiles segregated better than MUA profiles. Significant differences between CSD profiles evoked by different sounds were more pronounced at mid and late latencies in the granular and infragranular layers and these differences were based on the absence and/or presence of current sinks and on sink timing. The stimulus-specific activity patterns observed within cortical columns suggests that the joint activity of local cortical populations (as local as single columns) could indeed be important for encoding sounds that differ in their acoustic attributes. | eng_Latn | 10,586 |
A Tychonoff space X is called an SV-space if for every prime ideal P of the ring C(X) of continuous real-valued functions on X, the ordered integral domain C (X) P is a valuation ring (i.e., of any two nonzero elements of C (X) P , one divides the other). It is shown that X is an SV-space iff υX is an SV-space iff βX is an SV-space. If every point of X has a neighborhood that is an F-space, then X is an SV-space. An example is supplied of an infinite compact SV-space such that any point with an F-space neighborhood is isolated. It is shown that the class of SV-spaces includes those Tychonoff spaces that are finite unions of C∗-embedded SV-spaces. Some open problems are posed. | Real closed rings arise in semi-algebraic geometry and topology as well as in the investigation of partially ordered rings. It is shown that localizations of real closed rings with respect to Gabriel filters, or more generally: multiplicative filters, are again real closed. Thus, real closedness is preserved under a large number of important ring theoretic constructions. For a few particularly simple cases the multiplicative filters are classified and the localizations are determined. | The effect of spatial separation on the ability of listeners to report keywords from two simultaneous talkers was examined. The talkers were presented with equal intensity at a clearly audible level, and were designed to have little spectral overlap in order to reduce energetic interference. The two talkers were presented in a virtual auditory environment with various angular separations around references of -45o, 0o, or 45o azimuth. In Experiment 1, the virtual space was created using head-related transfer functions (HRTFs) which contained natural energy variations as a function of location. In Experiment 2, these energy variations were removed and the virtual space was created using only interaural time differences (ITDs). Overall, performance did not vary dramatically but depended on spatial separation, reference direction, and type of simulation. Around the 0o reference azimuth, performance in the HRTF condition tended to first increase and then decrease with increasing separation. This effect was greatly reduced in the ITD condition and thus appears to be related primarily to energy variations at the two ears. For sources around the ± 45o reference azimuths, there was an advantage to separating the two sources in both HRTF and ITD conditions, suggesting that perceived spatial separation is advantageous in a divided attention task, at least for lateral sources. | eng_Latn | 10,587 |
Functional Magnetic Resonance Imaging (fMRI) is one of the most widely used tools to study the neural underpinnings of human cognition. Standard analysis of fMRI data relies on a General Linear Model (GLM) approach to separate stimulus induced signals from noise. Crucially, this approach relies on a number of assumptions about the data which, for inferences to be valid, must be met. The current paper reviews the GLM approach to analysis of fMRI time-series, focusing in particular on the degree to which such data abides by the assumptions of the GLM framework, and on the methods that have been developed to correct for any violation of those assumptions. Rather than biasing estimates of effect size, the major consequence of non-conformity to the assumptions is to introduce bias into estimates of the variance, thus affecting test statistics, power and false positive rates. Furthermore, this bias can have pervasive effects on both individual subject and group-level statistics, potentially yielding qualitatively different results across replications, especially after the thresholding procedures commonly used for inference-making. | Functional imaging gives us increasingly detailed information about the location of brain activity. To use this information, we need a clear conception of the meaning of location data. Here, we review methods for reporting location in functional imaging and discuss the problems that arise from the great variability in brain anatomy between individuals. These problems cause uncertainty in localization, which limits the effective resolution of functional imaging, especially for brain areas involved in higher cognitive function. | By using a superluminescent diode as the light source and a depolariser inside the fibre coil, a constant scale factor is achieved without using polarisation control elements. For long-term behaviour an RMS-bias drift of 10 degrees/h is obtained. | eng_Latn | 10,588 |
Previously published reports have sought to elucidate the development of visual recognition memory in the human infant by investigating the modulation of infant ERPs by a familiar and novel face (e.g., de Haan and Nelson, 1997 , de Haan and Nelson, 1999 . Variability in infants’ brain responses elicited under the same mnemonic condition, however, has not been previously examined. The present report undertook two separate analyses in order to examine two kinds of variability: variability in the brain’s response to a stimulus over time as a function of stimulus repetition, and variability in the brain’s response between subjects as a function of the total number of trials completed in an ERP session. There were three major findings: (a) the mid-latency negative component (Nc) and long-latency slow wave (SW) were found to dissociate cognitive processes associated with familiarity from processes associated with stimulus repetition, (b) individual differences in the number of trials an infant completes in an ERP session were observed to be associated with differences in the amplitude and latency of the Nc, and (c) individual differences in the number of trials an infant completes appear to reflect differences in the extent to which the familiar and novel faces are encoded. The implications of these results are discussed with respect to models of habituation and preferential looking, infant ERP methodology, and developmental processes. | The ability to recall contextual details associated with an event begins to develop in the first year of life, yet adult levels of recall are not reached until early adolescence. Dual-process models of memory suggest that the distinct retrieval process that supports the recall of such contextual information is recollection. In the present investigation, we used both behavioral and electrophysiological measures to assess the development of memory for contextual details, as indexed by memory for temporal order, in early childhood. Results revealed age-related improvements in memory for temporal order despite similar levels of memory for the individual items themselves. Furthermore, this pattern of recall was associated with specific components in the electrophysiological response. Consistent with electrophysiological research in adults, distributed, positive-going activity late in the waveform was associated with increases in recall of contextual details and the development of recollective processes. | Every function of n inputs can be efficiently computed by a complete network of n processors in such a way that: If no faults occur, no set of size t n /2 of players gets any additional information (other than the function value), Even if Byzantine faults are allowed, no set of size t n /3 can either disrupt the computation or get additional information. Furthermore, the above bounds on t are tight! | eng_Latn | 10,589 |
Currently there is no effective or standardized population survey technique for estimating abundance of band-tailed pigeons (Columbafasciata). I evaluated a point count technique for estimating relative abundance of band-tailed pigeons. I counted band-tailed pigeons detected by coo call at random point locations in the central Coast Range of Oregon between mid-May and mid-August 1996-98. Counts began 10 minutes before local sunrise and lasted 1 hour. Also, I recorded band-tailed pigeon coo calls to determine coo call characteristics and audibility. Band-tailed pigeons cooed 1-50 times during point counts. Coos lasted about 8-9 seconds, had a maximum intensity frequency range of 200-500 Hz, and could be detected from >1,000 m away. The intervals of 16 June-24 July and 25 July-16 August provided uniform periods of detection probability; however, a multiplicative factor of 0.49 must be added to second period counts for unbiased comparisons between periods. The probability of detecting a band-tailed pigeon during point counts <60 minutes depended on survey length, and increased about 1.5% per minute. During point counts, new detections in 6 10-minute intervals ranged from 11-25%. Point counts of cooing band-tailed pigeons offer an effective means of estimating abundance. Point counts should: be 800 m apart, begin 10 minutes before official local sunrise, last 1-hour in duration, and in the Coast Range of Oregon, be conducted during 16 June-24 July, or if necessary 25 July-16 August. The technique should be applicable anywhere in the breeding range of the band-tailed pigeon; however, the uniform period of peak calling activity may need verification. | Geophagy is widespread and well documented for mammals, but avian geophagy has only recently become the subject of serious scientific investigation. I analyzed data from 606 mornings of observations at a large avian geophagy site or “clay lick” in the southwestern Amazon Basin to examine the effects of weather on bird lick use. Birds used the clay lick on 94% of the mornings without precipitation or fog. Parrots dominated the site in both numbers of species (17) and individuals (>99%). Weather conditions were significantly correlated with total lick use: there was greater use on sunny mornings and less on rainy mornings. Fog and overnight rain were correlated with low lick use. Sun, rain, fog, and overnight rain were recorded on 47, 25, 20, and 8% of the mornings, respectively. I estimated that inclement weather caused an annual 29% reduction in geophagy for all bird species combined. When early morning rain prevented species from using the lick, they did not return later in the day nor did they ... | Summary Perception routinely integrates inputs from different senses. Stimulus temporal proximity critically determines whether or not these inputs are bound together. Despite the temporal window of integration being a widely accepted notion, its neurophysiological substrate remains unclear. Many types of common audio-visual interactions occur within a time window of ∼100 ms [1–5]. For example, in the sound-induced double-flash illusion, when two beeps are presented within ∼100 ms together with one flash, a second illusory flash is often perceived [2]. Due to their intrinsic rhythmic nature, brain oscillations are one candidate mechanism for gating the temporal window of integration. Interestingly, occipital alpha band oscillations cycle on average every ∼100 ms, with peak frequencies ranging between 8 and 14 Hz (i.e., 120–60 ms cycle). Moreover, presenting a brief tone can phase-reset such oscillations in visual cortex [6, 7]. Based on these observations, we hypothesized that the duration of each alpha cycle might provide the temporal unit to bind audio-visual events. Here, we first recorded EEG while participants performed the sound-induced double-flash illusion task [4] and found positive correlation between individual alpha frequency (IAF) peak and the size of the temporal window of the illusion. Participants then performed the same task while receiving occipital transcranial alternating current stimulation (tACS), to modulate oscillatory activity [8] either at their IAF or at off-peak alpha frequencies (IAF±2 Hz). Compared to IAF tACS, IAF−2 Hz and IAF+2 Hz tACS, respectively, enlarged and shrunk the temporal window of illusion, suggesting that alpha oscillations might represent the temporal unit of visual processing that cyclically gates perception and the neurophysiological substrate promoting audio-visual interactions. | eng_Latn | 10,590 |
Background: While consciousness and top-down attention seem to be inextricably connected, recent evidence has suggested that these processes can be present in the absence of the other. Recent studies show that observers can pay attention to an invisible stimulus (unconscious), and that a stimulus can be clearly seen in the absence of attention. We used a novel psychophysics task to explore the neural correlates of top-down attention and consciousness. Method: The task is meant to confirm that these two processes are independent from one another. EEG were recorded during the task from 45 subjects in occipital, Parietal and frontal lobes. Target-locked ERPs for masked and unmasked condition were constructed. Time features corresponding to P100, ,200 and P300 components (i.e. correlate candidates of consciousness and attention) were extracted for all eight channels separately. Results: The results indicate that some of the mentioned components are increased when attention or consciousness occurs. By comparing difference waves in each condition separably, we found that increase in positivity in P100 window is the only ERP correlate of consciousness and decrease in negativity in N100,200 window and increase in positivity in P300 window are ERP correlates of attention in O1, O2, PO7 and PO8 which are relevant channels. Conclusions: Our task could separate attention and consciousness successfully through their neural correlates. Our results introduce new ERP correlates of attention and consciousness. The results also suggest that these ERP components are meaningful features for the distinction between these two concepts. To our knowledge, this is the first time that these correlates of consciousness and specially attention are introduced in separable method. | It is not clear whether attention is necessary or not for consciousness. We studied the relationship between attention and consciousness by tracking their electrophysiological correlates. The participants attended to visual targets, ignored nontargets in the prespecified visual field and ignored all stimuli in the opposite field. Visual consciousness was varied by masking. Our results showed that the earliest electrophysiological correlate of consciousness emerged independent of the manipulations of spatial and nonspatial attention. Conversely, the electrophysiological correlate of attention, selection negativity, was elicited regardless of the presence or absence of consciousness. Only the correlates of later, higher-level conscious processes strongly depended on attention. Thus, the electrophysiological brain responses reflecting visual consciousness and attention are initially independent of each other. | this failure of Europanization in these countries is correlated with the preferences of the ruling elites in these countries. | eng_Latn | 10,591 |
We present a unified statistical theory for assessing the significance of apparent signal observed in noisy difference images. The results are usable in a wide range of applications, including fMRI, but are discussed with particular reference to PET images which represent changes in cerebral blood flow elicited by a specific cognitive or sensorimotor task. Our main result is an estimate of the P-value for local maxima of Gaussian, t, chi(2) and F fields over search regions of any shape or size in any number of dimensions. This unifies the P-values for large search areas in 2-D (Friston et al. [1991]: J Cereb Blood Flow Metab 11:690-699) large search regions in 3-D (Worsley et al. [1992]: J Cereb Blood Flow Metab 12:900-918) and the usual uncorrected P-value at a single pixel or voxel. (C) 1996 Wiley-Liss, Inc. | A method for detecting significant and regionally specific correlations between sensory input and the brain's physiological response, as measured with functional magnetic resonance imaging (MRI), is presented in this paper. The method involves testing for correlations between sensory input and the hemodynamic response after convolving the sensory input with an estimate of the hernodynamic response function. This estimate is obtained without reference to any assumed input. To lend the approach statistical validity, it is brought into the framework of statistical parametric mapping by using a measure of cross-correlations between sensory input and hemodynamic response that is valid in the presence of intrinsic autocorrelations. These autocorrelations are necessarily present, due to the hemodynamic response function or temporal point spread function. | not available DOI: http://dx.doi.org/10.3329/pulse.v5i2.20263 Pulse Vol.5 July 2011 p.31-40 | eng_Latn | 10,592 |
Developmental Language Impairment (DLI) is a neurodevelopmental disorder affecting 12% to 14% of the school-age children in the United States. While substantial studies have shown a wide range of linguistic and non-linguistic difficulty in individuals with DLI, very little is known about the neuroanatomical mechanisms underlying this disorder. In the current study, we examined the subcortical components of the corticostriatal system in young adults with DLI, including the caudate nucleus, the putamen, the nucleus accumbens, the globus pallidus, and the thalamus. Additionally, the four cerebral lobes and the hippocampus were also comprised for an exploratory analysis. We used conventional magnetic resonance imaging (MRI) to measure regional brain volumes, as well as diffusion tensor imaging (DTI) to assess water diffusion anisotropy as quantified by fractional anisotropy (FA). Two groups of participants, one with DLI (n=12) and the other without (n=12), were recruited from a prior behavioral study, and all were matched on age, gender, and handedness. Volumetric analyses revealed region-specific abnormalities in individuals with DLI, showing pathological enlargement bilaterally in the putamen and the nucleus accumbens, and unilaterally in the right globus pallidus after the intracranial volumes were controlled. Regarding the DTI findings, the DLI group showed decreased FA values in the globus pallidus and the thalamus but these significant differences disappeared after controlling for the whole-brain FA value, indicating that microstructural abnormality is diffuse and affects other regions of the brain. Taken together, these results suggest region-specific corticostriatal abnormalities in DLI at the macrostructural level, but corticostriatal abnormalities at the microstructural level may be a part of a diffuse pattern of brain development. Future work is suggested to investigate the relationship between corticostriatal connectivity and individual differences in language development. | Specific language impairment (SLI) is a developmental disorder linked to deficient auditory processing. In this magnetoencephalography (MEG) study we investigated a specific prolonged auditory response (N250m) that has been reported predominantly in children and is associated with level of language skills. We recorded auditory responses evoked by sine-wave tones presented alternately to the right and left ear of 9–10-year-old children with SLI (n = 10) and children with typical language development (n = 10). Source analysis was used to isolate the N250m response in the left and right hemisphere. In children with language impairment left-hemisphere N250m responses were enhanced compared to those of controls, while no group difference was found in the right hemisphere. Consequently, language impaired children lacked the typical right-ward asymmetry that was found in control children. Furthermore, left but not right hemisphere N250m responses correlated positively with performance on a phonological processing task in the SLI group exclusively, possibly signifying a compensatory mechanism for delayed maturation of language processing. These results suggest that enhanced left-hemisphere auditory activation reflects a core neurophysiological manifestation of developmental language disorders, and emphasize the relevance of this developmentally specific activation pattern for competent language development. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 10,593 |
Somatosensory, brainstem auditory evoked and peripheral sensory-motor responses were recorded in rats anaesthetized with either pentobarbital or a ketamine-xylazine combination. This was carried out in order to assess which of these agents degraded responses to a lesser extent and thus would be more suitable for monitoring experimental effects. Neither of the anaesthetic agents affected peripheral sensory or motor conduction, nor were there any interpeak latency changes of the early components of the brainstem auditory response. However, pentobarbital anaesthesia resulted in an increase in latency of the initial positive component of the somatosensory cortical evoked potential and attenuation of the following negative component. During the recovery stages of ketamine-xylazine anaesthesia the longer latency evoked potential components were observed to emerge. | In mammals, acoustic communication plays an important role during social behaviors. Despite their ethological relevance, the mechanisms by which the auditory cortex represents different communication call properties remain elusive. Recent studies have pointed out that communication-sound encoding could be based on discharge patterns of neuronal populations. Following this idea, we investigated whether the activity of local neuronal networks, such as those occurring within individual cortical columns, is sufficient for distinguishing between sounds that differed in their spectro-temporal properties. To accomplish this aim, we analyzed simple pure-tone and complex communication call elicited multi-unit activity (MUA) as well as local field potentials (LFP), and current source density (CSD) waveforms at the single-layer and columnar level from the primary auditory cortex of anesthetized Mongolian gerbils. Multi-dimensional scaling analysis was used to evaluate the degree of “call-specificity” in the evoked activity. The results showed that whole laminar profiles segregated 1.8-2.6 times better across calls than single-layer activity. Also, laminar LFP and CSD profiles segregated better than MUA profiles. Significant differences between CSD profiles evoked by different sounds were more pronounced at mid and late latencies in the granular and infragranular layers and these differences were based on the absence and/or presence of current sinks and on sink timing. The stimulus-specific activity patterns observed within cortical columns suggests that the joint activity of local cortical populations (as local as single columns) could indeed be important for encoding sounds that differ in their acoustic attributes. | Corruption, which is a persistent feature in human societies throughout time and space, affects not only the administration of the state but also every societal organ including the church. The ‘virus of corruption’ has penetrated into functioning systems of the various stakeholders both locally and globally. Various approaches have been used in trying to curb corruption at different levels from a secular perspective, but with little progress as the vice eminently still exists in the society. To the contrary and from a theological perspective, the long-lasting solutions in curbing corruption are realised through engaging the main root cause of the problem, which in this case is the heart of man. Theologically, ken ō sis as a theoretical framework and solution goes beyond the gist of secular approaches as it addresses issues of the hearts of men which in turn produces reformed systems. In this article, I look into ken ō sis of the Synod operational system in relation to imitating the incarnate work of Christ. The article assesses the Synod anti-corruption initiatives from a ken ō sis perspective and then identifies and proposes the effective steps to improve and strengthen the Synod’s kenotic actions in Public Square. The CCAP Livingstonia Synod assessment process is geared to show how far kenotic the church must go in emulating and confronting systems as a way of fulfilling the demands of incarnation and works of Christ. This highlights the critical areas that add value in the Synod’s public engagement in anti-corruption. Intradisciplinary and/or interdisciplinary implications: This is an interdisciplinary article that focuses on systematic, church history, public theology and social development. The article assesses the public role of the church in anti-corruption and provides a paradigm shift in the fight against corruption from secular to theological based approaches. | eng_Latn | 10,594 |
Size constancy is the result of cognitive scaling operations that enable us to perceive an object as having the same size when presented at different viewing distances. In this article, we review the literature on size and distance perception to form an overarching synthesis of how the brain might combine retinal images and distance cues of retinal and extra-retinal origin to produce a perceptual visual experience of a world where objects have a constant size. A convergence of evidence from visual psychophysics, neurophysiology, neuropsychology, electrophysiology and neuroimaging highlight the primary visual cortex (V1) as an important node in mediating size-distance scaling. It is now evident that this brain area is involved in the integration of multiple signals for the purposes of size perception and does much more than fulfil the role of an entry position in a series of hierarchical cortical events. We also discuss how information from other sensory modalities can also contribute to size-distance scaling and shape our perceptual visual experience. | Specific abnormalities of vision in schizophrenia have been observed to affect high-level and some low-level integration mechanisms, suggesting that people with schizophrenia may experience anomalies across different stages in the visual system affecting either early or late processing or both. Here, we review the research into visual illusion perception in schizophrenia and the issues which previous research has faced. One general finding that emerged from the literature is that those with schizophrenia are mostly immune to the effects of high-level illusory displays, but this effect is not consistent across all low-level illusions. The present review suggests that this resistance is due to the weakening of top–down perceptual mechanisms and may be relevant to the understanding of symptoms of visual distortion rather than hallucinations as previously thought. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,595 |
Standard inference in neuroimaging consists in describing brain activations elicited and modulated by different kinds of stimuli. Recently however, paradigms have been studied in which the converse operation is performed, thus inferring behavioral or mental states associated with activation images. Here, we use the well-known retinotopy of the visual cortex to infer the visual content of real scenes from the activation patterns that they elicit. We present an explicit decoding technique, based on the current knowledge of the retinotopic structure of the visual areas. Our algorithm can predict the stimulus identity with significant accuracy. | Functional magnetic resonance imaging (fMRI) was used to estimate the average receptive field sizes of neurons in each of several striate and extrastriate visual areas of the human cerebral cortex. The boundaries of the visual areas were determined by retinotopic mapping procedures and were visualized on flattened representations of the occipital cortex. Estimates of receptive field size were derived from the temporal duration of the functional activation at each cortical location as a visual stimulus passed through the receptive fields represented at that location. Receptive fields are smallest in the primary visual cortex (V1). They are larger in V2, larger again in V3/VP and largest of all in areas V3A and V4. In all these areas, receptive fields increase in size with increasing stimulus eccentricity. The results are qualitatively in line with those obtained by others in macaque monkeys using neurophysiological methods. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,596 |
In this paper, we introduce a new model called Latent Mixture of Discriminative Experts which can automatically learn the temporal relationship between different modalities. Since, we train separate experts for each modality, LMDE is capable of improving the prediction performance even with limited amount of data. For model interpretation, we present a sparse feature ranking algorithm that exploits L1 regularization. An empirical evaluation is provided on the task of listener backchannel prediction (i.e., head nod). We introduce a new error evaluation metric called User-adaptive Prediction Accuracy that takes into account the difference in people's backchannel responses. Our results confirm the importance of combining five types of multimodal features: lexical, syntactic structure, part-of-speech, visual and prosody. Latent Mixture of Discriminative Experts model outperforms previous approaches. | If a dialog system can respond to a user as naturally as a human, the interaction will be smoother. In this research, we aim to develop a dialog system by emulating the human behavior in a chat-like dialog. In this paper, we developed a dialog system which could generate chat-like responses and their timing using a decision tree. The system could perform "collaborative completion," "aizuchi" (back-channel) and so on. The decision tree utilized the pitch and the power contours of user's utterance, recognition hypotheses, and response preparation status of the response generator, at every time segment as features to generate response timing. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 10,597 |
This paper reports on the performance of the Neuromorphic IRFPA, the first IRFPA designed and fabricated to conduct temporal and spatial processing on the focal plane. The Neuromorphic IRFPA's unique on-chip processing capability can perform retina-like functions such as lateral inhibition and contrast enhancement, spatial and temporal filtering, image compression and edge enhancement, and logarithmic response. Previously, all evaluations of the Neuromorphic IRFPA camera have been performed on the analog video output. In the work leading up to this paper, the Neuromorphic was integrated to a digital recorder to collect quantitative laboratory and field data. This paper describes the operation and characterization of specific on-chip processes such as spatial and temporal kernel size control. The use of Neuromorphic on-chip processing in future IRFPAs is analyzed as applied to improving SNR via adaptive nonuniformity, charge handling, and dynamic range problems. | The harmonic input method of nonlinear system identification is modified to allow the Volterra series approach to be used for psychophysical investigation of various aspects of human pattern vision in the spatial frequency domain. While it is well known that only one modulation transfer function provides a complete characterization of a linear system, a number of multidimensional transfer functions are needed to identify a nonlinear system. We have shown, that so far as the contrast sensitivity to sine-wave gratings may be used for an empirical estimate of the first-order modulation transfer function of the human visual system, the contrast sensitivity to difference harmonics may be used as an empirical estimate of the second-order modulation transfer function. A difference harmonic arises from a mixture of two sine-wave gratings resulting from the nonlinearity of the visual system. Difference harmonic, experienced as some periodic beatlike structure, may still be observed if frequencies of the component gratings are higher than the maximum visual acuity. The visibility of the low-frequency beatlike pattern produced by pairs of sine-wave gratings, which themselves are of spatial frequencies too high to be resolved, could be accounted for either by a difference frequency distortion product ( Burton, 1973 ) or by a special beat detector ( Derrington & Badcock, 1985 ). We found that increasing the contrast of one component grating may be compensated for by reducing the contrast of the other component grating, the beatlike pattern being at threshold. This is exactly what would be expected if the beatlike pattern is detected because of the difference harmonics produced by nonlinearity of the visual system. We have determined contrast thresholds for the difference harmonics which occur between two unresolved different spatial frequencies. The contrast sensitivity function for difference harmonics was found to have a marked similarity both in the shape and position of peak sensitivity to the contrast sensitivity function for single sine-wave gratings. Another important characteristic of the contrast sensitivity function for difference harmonics is that it depends only on the frequency difference, Δf = f 1 − f 2 , rather than on the value of either f 1 or f 2 . All this indicates that a difference harmonic arises from local nonlinearities in the visual system. More specifically, the visual system may be represented as a cascade system, composed of a linear system with transfer function O(f) followed by a nonlinear element, r(·) , without spatial spread in cascade with another linear system with transfer function P(f) . The n th order transfer function of this cascade system, H n (f 1 ,...,f n ) can be expressed in the following way: H n (f 1 ,...,f n ) = a n O(f 1 )P(f 1 + ... + f n ) where a n is the n th coefficient in the Taylor series expansion for the nonlinear function r (·). It follows from this that the measurement of the first- and second-order transfer functions is sufficient to determine O(f) and P(f) . We have derived the estimates of c O(f) and P(f) from contrast sensitivity functions for single sine-wave gratings and difference harmonics by the least squares method. | Adverse, unfavourable life conditions, particularly during early life stages and infancy, can lead to epigenetic regulation of genes involved in stress-response, behavioral disinhibition, and cognitive-emotional systems. Over time, the ultimate final outcome can be expressed through behaviors bedeviled by problems with impulse control, such as eating disorders, alcoholism, and indiscriminate social behavior. While many reward gene polymorphisms are involved in impulsive behaviors, a polymorphism by itself may not translate to the development of a particular behavioral disorder unless it is impacted by epigenetic effects. Brain-derived neurotrophic factor (BDNF) affects the development and integrity of the noradrenergic, dopaminergic, serotonergic, glutamatergic, and cholinergic neurotransmitter systems, and plasma levels of the neurotrophin are associated with both cognitive and aggressive impulsiveness. Epigenetic mechanisms associated with a multitude of environmental factors, including premature birth, low birth weight, prenatal tobacco exposure, non-intact family, young maternal age at birth of the target child, paternal history of antisocial behavior, and maternal depression, alter the developmental trajectories for several neuropsychiatric disorders. These mechanisms affect brain development and integrity at several levels that determine structure and function in resolving the final behavioral expressions. | eng_Latn | 10,598 |
The spatial selectivity of the electroretinogram in response to pattern onset-offset stimuli was studied in man at several levels of adaptation ranging from scotopic to photopic levels. Under conditions of rod function the peak of the spatial selectivity based on amplitude measurements of the pattern-onset response occurs at a low spatial frequency. With increasing light adaptation a gradual shift of the selectivity to higher spatial frequencies occurs. This change in the character of the response can be explained by the assumption that antagonistic center-surround retinal receptive fields contribute to the response, which are larger under scotopic than under photopic levels of stimulation. | The pattern properties of the visually evoked potential and the electroretinogram have been investigated for phase alternated patterns of checks presented to the near periphery of the retina. When the eye was light-adapted, coarse patterns became relatively more effective for eliciting the evoked potential as the stimulus was moved away from the fovea. Fine patterns were most effective in the center of the field. The electroretinogram responded best to coarse spatial frequencies at all retinal locations. At a lower level of light adaptation the sensitivity of the evoked potential shifted to coarse spatial frequencies in the center of the field, but did not change appreciably in the periphery. The results may reflect some of the dynamic properties of visual fields. | This paper presents two novel generic adaptive batching schemes for replicated servers. Both schemes are oblivious to the underlying communication protocols. Our novel schemes adapt their batching levels automatically and immediately according to the current communication load. This is done without any explicit monitoring or calibration of the system. Additionally, the paper includes a detailed performance evaluation. | eng_Latn | 10,599 |
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