40,664 research outputs found

    TGF beta type II receptor signaling controls Schwann cell death and proliferation in developing nerves

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    During development, Schwann cell numbers are precisely adjusted to match the number of axons. It is essentially unknown which growth factors or receptors carry out this important control in vivo. Here, we tested whether the type II transforming growth factor (TGF)beta receptor has a role in this process. We generated a conditional knock-out mouse in which the type II TGF beta receptor is specifically ablated only in Schwann cells. Inactivation of the receptor, evident at least from embryonic day 18, resulted in suppressed Schwann cell death in normally developing and injured nerves. Notably, the mutants also showed a strong reduction in Schwann cell proliferation. Consequently, Schwann cell numbers in wild-type and mutant nerves remained similar. Lack of TGF beta signaling did not appear to affect other processes in which TGF beta had been implicated previously, including myelination and response of adult nerves to injury. This is the first in vivo evidence for a growth factor receptor involved in promoting Schwann cell division during development and the first genetic evidence for a receptor that controls normal developmental Schwann cell death

    Spatial integration of optic flow information in direction of heading judgments

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    While we know that humans are extremely sensitive to optic flow information about direction of heading, we do not know how they integrate information across the visual field. We adapted the standard cue perturbation paradigm to investigate how young adult observers integrate optic flow information from different regions of the visual field to judge direction of heading. First, subjects judged direction of heading when viewing a three-dimensional field of random dots simulating linear translation through the world. We independently perturbed the flow in one visual field quadrant to indicate a different direction of heading relative to the other three quadrants. We then used subjects' judgments of direction of heading to estimate the relative influence of flow information in each quadrant on perception. Human subjects behaved similarly to the ideal observer in terms of integrating motion information across the visual field with one exception: Subjects overweighted information in the upper half of the visual field. The upper-field bias was robust under several different stimulus conditions, suggesting that it may represent a physiological adaptation to the uneven distribution of task-relevant motion information in our visual world

    FACSGen 2.0 animation software: Generating 3D FACS-valid facial expressions for emotion research

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    In this article, we present FACSGen 2.0, new animation software for creating static and dynamic three-dimensional facial expressions on the basis of the Facial Action Coding System (FACS). FACSGen permits total control over the action units (AUs), which can be animated at all levels of intensity and applied alone or in combination to an infinite number of faces. In two studies, we tested the validity of the software for the AU appearance defined in the FACS manual and the conveyed emotionality of FACSGen expressions. In Experiment 1, four FACS-certified coders evaluated the complete set of 35 single AUs and 54 AU combinations for AU presence or absence, appearance quality, intensity, and asymmetry. In Experiment 2, lay participants performed a recognition task on emotional expressions created with FACSGen software and rated the similarity of expressions displayed by human and FACSGen faces. Results showed good to excellent classification levels for all AUs by the four FACS coders, suggesting that the AUs are valid exemplars of FACS specifications. Lay participants' recognition rates for nine emotions were high, and comparisons of human and FACSGen expressions were very similar. The findings demonstrate the effectiveness of the software in producing reliable and emotionally valid expressions, and suggest its application in numerous scientific areas, including perception, emotion, and clinical and neuroscience research

    Coalition Resilient Outcomes in Max k-Cut Games

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    We investigate strong Nash equilibria in the \emph{max kk-cut game}, where we are given an undirected edge-weighted graph together with a set {1,,k}\{1,\ldots, k\} of kk colors. Nodes represent players and edges capture their mutual interests. The strategy set of each player vv consists of the kk colors. When players select a color they induce a kk-coloring or simply a coloring. Given a coloring, the \emph{utility} (or \emph{payoff}) of a player uu is the sum of the weights of the edges {u,v}\{u,v\} incident to uu, such that the color chosen by uu is different from the one chosen by vv. Such games form some of the basic payoff structures in game theory, model lots of real-world scenarios with selfish agents and extend or are related to several fundamental classes of games. Very little is known about the existence of strong equilibria in max kk-cut games. In this paper we make some steps forward in the comprehension of it. We first show that improving deviations performed by minimal coalitions can cycle, and thus answering negatively the open problem proposed in \cite{DBLP:conf/tamc/GourvesM10}. Next, we turn our attention to unweighted graphs. We first show that any optimal coloring is a 5-SE in this case. Then, we introduce xx-local strong equilibria, namely colorings that are resilient to deviations by coalitions such that the maximum distance between every pair of nodes in the coalition is at most xx. We prove that 11-local strong equilibria always exist. Finally, we show the existence of strong Nash equilibria in several interesting specific scenarios.Comment: A preliminary version of this paper will appear in the proceedings of the 45th International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM'19

    The blood-to-plasma ratio and predicted GABA<inf>A</inf>-binding affinity of designer benzodiazepines

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    Purpose: The number of benzodiazepines appearing as new psychoactive substances (NPS) is continually increasing. Information about the pharmacological parameters of these compounds is required to fully understand their potential effects and harms. One parameter that has yet to be described is the blood-to-plasma ratio. Knowledge of the pharmacodynamics of designer benzodiazepines is also important, and the use of quantitative structure–activity relationship (QSAR) modelling provides a fast and inexpensive method of predicting binding affinity to the GABAA receptor. Methods: In this work, the blood-to-plasma ratios for six designer benzodiazepines (deschloroetizolam, diclazepam, etizolam, meclonazepam, phenazepam, and pyrazolam) were determined. A previously developed QSAR model was used to predict the binding affinity of nine designer benzodiazepines that have recently appeared. Results: Blood-to-plasma values ranged from 0.57 for phenazepam to 1.18 to pyrazolam. Four designer benzodiazepines appearing since 2017 (fluclotizolam, difludiazepam, flualprazolam, and clobromazolam) had predicted binding affinities to the GABAA receptor that were greater than previously predicted binding affinities for other designer benzodiazepines. Conclusions: This work highlights the diverse nature of the designer benzodiazepines and adds to our understanding of their pharmacology. The greater predicted binding affinities are a potential indication of the increasing potency of designer benzodiazepines appearing on the illicit drugs market

    Self Esteem between Assam Police Trainees and Sports persons - A Comparative Study

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    The aim of the study was to compare self esteem between Assam Police trainees and sports persons. The researchers selected total 50 (fifty) subject’s i.e. N1=25 Assam Police (AP) trainees from 2nd AP Battalion Camp, Makum, Tinsukia, Assam, India and N2=25 sports person from Dibrugarh University Post Graduate team participated different Inter-college level Tournament and between the 19-22 years age. The purposive sampling technique was used to select the subjects. To collect the data, the Rosenberg Self-Esteem Scale was used. To determine the differences between the groups the Independent t-test was applied and the level of significance was kept at 0.05confidence. The result showed that statistically there was significant difference between the groups (t0.05 (48) = 3.55 &gt; 1.677)

    Ab initio calculations of structural and electronic properties of CdTe clusters

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    We present results of a study of small stoichiometric CdnTenCd_{n}Te_{n} (1n61{\leq}n{\leq}6) clusters and few medium sized non-stoichiometric CdmTenCd_{m}Te_{n} [(m,n=13,16,19m,n= 13, 16, 19); (mnm{\neq}n)] clusters using the Density Functional formalism and projector augmented wave method within the generalized gradient approximation. Structural properties {\it viz.} geometry, bond length, symmetry and electronic properties like HOMO-LUMO gap, binding energy, ionization potential and nature of bonding {\it etc.} have been analyzed. Medium sized non-stoichiometric clusters were considered as fragments of the bulk with T{d_{d}} symmetry. It was observed that upon relaxation, the symmetry changes for the Cd rich clusters whereas the Te rich clusters retain their symmetry. The Cd rich clusters develop a HOMO-LUMO gap due to relaxation whereas there is no change in the HOMO-LUMO gap of the Te rich clusters. Thus, the symmetry of a cluster seems to be an important factor in determining the HOMO-LUMO gap.Comment: 8 pages 16 figure
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