A dynamic neural field model of temporal order judgments

Temporal ordering of events is biased, or influenced, by perceptual organization—figure–ground organization—and by spatial attention. For example, within a region assigned figural status or at an attended location, onset events are processed earlier (Lester, Hecht, & Vecera, 2009; Shore, Spence, & Klein, 2001), and offset events are processed for longer durations (Hecht & Vecera, 2011; Rolke, Ulrich, & Bausenhart, 2006). Here, we present an extension of a dynamic field model of change detection (Johnson, Spencer, Luck, & Schöner, 2009; Johnson, Spencer, & Schöner, 2009) that accounts for both the onset and offset performance for figural and attended regions. The model posits that neural populations processing the figure are more active, resulting in a peak of activation that quickly builds toward a detection threshold when the onset of a target is presented. This same enhanced activation for some neural populations is maintained when a present target is removed, creating delays in the perception of the target’s offset. We discuss the broader implications of this model, including insights regarding how neural activation can be generated in response to the disappearance of information. (PsycINFO Database Record (c) 2015 APA, all rights reserved

Transport, Magnetic and Vibrational Properties of Chemically Exfoliated Few Layer Graphene

We study the vibrational, magnetic and transport properties of Few Layer Graphene (FLG) using Raman and electron spin resonance spectroscopy and microwave conductivity measurements. FLG samples were produced using wet chemical exfoliation with different post-processing, namely ultrasound treatment, shear mixing, and magnetic stirring. Raman spectroscopy shows a low intensity D mode which attests a high sample quality. The G mode is present at $1580$ cm$^{-1}$ as expected for graphene. The 2D mode consists of 2 components with varying intensities among the different samples. This is assigned to the presence of single and few layer graphene in the samples. ESR spectroscopy shows a main line in all types of materials with a width of about $1$ mT and and a $g$-factor in the range of $2.005-2.010$. Paramagnetic defect centers with a uniaxial $g$-factor anisotropy are identified, which shows that these are related to the local sp$^2$ bonds of the material. All kinds of investigated FLGs have a temperature dependent resistance which is compatible with a small gap semiconductor. The difference in resistance is related to the different grain size of the samples

What we observe is biased by what other people tell us: beliefs about the reliability of gaze behavior modulate attentional orienting to gaze cues

For effective social interactions with other people, information about the physical environment must be integrated with information about the interaction partner. In order to achieve this, processing of social information is guided by two components: a bottom-up mechanism reflexively triggered by stimulus-related information in the social scene and a top-down mechanism activated by task-related context information. In the present study, we investigated whether these components interact during attentional orienting to gaze direction. In particular, we examined whether the spatial specificity of gaze cueing is modulated by expectations about the reliability of gaze behavior. Expectations were either induced by instruction or could be derived from experience with displayed gaze behavior. Spatially specific cueing effects were observed with highly predictive gaze cues, but also when participants merely believed that actually non-predictive cues were highly predictive. Conversely, cueing effects for the whole gazed-at hemifield were observed with non-predictive gaze cues, and spatially specific cueing effects were attenuated when actually predictive gaze cues were believed to be non-predictive. This pattern indicates that (i) information about cue predictivity gained from sampling gaze behavior across social episodes can be incorporated in the attentional orienting to social cues, and that (ii) beliefs about gaze behavior modulate attentional orienting to gaze direction even when they contradict information available from social episodes

A Study in Achievement of College Freshmen Using The American Council of Education Cooperative Biology Test

The purpose of this study was to discover significant differences in achievement , if any, of boys and girls from the three classes of high schools in Kansas . This brings one to the statement of the problem which may be stated as follows: A Study in Achievement of College Freshmen using the American Council of Education Cooperative Biology Test . Form P. 11 The problem was to discover: (1) significant differences , if any, between boys who had biology in high school and those who did not ; (2) significant differences, if any, between girls who had biology in high school and those who did not; (3) significant differences , if any, between the above mentioned groups from class A , B , and “C” schools; (4) significant difference, if any, between boys and girls used in this study

Precise determination of graphene functionalization by in situ Raman spectroscopy

The verification of a successful covalent functionalization of graphene and related carbon allotropes can easily be carried out by Raman spectroscopy. Nevertheless, the unequivocal assignment and resolution of individual lattice modes associated with the covalent binding of addends was elusive up to now. Here we present an in situ Raman study of a controlled functionalization of potassium intercalated graphite, revealing several new bands appearing in the D-region of the spectrum. The evolution of these bands with increasing degree of functionalization from low to moderate levels provides a basis for the deconvolution of the different components towards quantifying the extent of functionalization. By complementary DFT calculations we were able to identify the vibrational changes in the close proximity of the addend bearing lattice carbon atoms and to assign them to specific Raman modes. The experimental in situ observation of the developing functionalization along with the reoxidation of the intercalated graphite represents an important step towards an improved understanding of the chemistry of graphene

Geometrical Heavy Lifting: Yang-Mills, Spin, and Torsion in Dynamical Projective Gravitation

Thomas-Whitehead (TW) gravity is a gauge theory of gravitation based on projective geometry. The theory maintains projective symmetry through the TW connection, an affine connection over the volume bundle of the spacetime manifold. TW gravity obtains dynamics through Lovelock expansions in the action while preserving general relativity as a weak field limit. In this paper we clarify the process of lifting tensor and spinor fields from spacetime to the volume bundle and demonstrate that a choice of lifting amounts to a gauge fixing condition. This leads to a natural extension of previous work, where we now realize these prior constructions have been restricted to a particular gauge. In pursuit of generality, we also introduce torsion to the TW connection, leading to new dynamics. In particular, the appearance of torsion induces interaction terms involving gravitational coupling with Yang-Mills fields and Dirac spinors. An explicit realization of this is a geometrically sourced chiral mass term arising from the torsion dynamics

Theta Function Uniformization of Elliptic Curves

The interplay between elliptic curves, modular forms, and Riemann surfaces has beenlong studied, with a history dating back to Jacobi and Weierstrass. In particular, the Uniformization theorem implies all elliptic curves are Riemann surfaces of genus 1. Under this interpretation modular forms appear as line bundles over the moduli space of elliptic curves and as differential forms on the associated Riemann surface.More recently, Shimura, Zagier, and others have made a ‘modular dictionary’, whereintheta functions are modular forms for certain congruence subgroups, while Eisenstein series can be expressed in terms of theta functions. Here we study their work in the case of elliptic curves, resulting in a novel parametrization of elliptic curves by the Jacobi theta constants. This procedure not only classifies elliptic curves up to isomorphism but contains further information about the associated modular invariants

Adolescence

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