5,631 research outputs found

    Bistable Gestalts reduce activity in the whole of V1, not just the retinotopically predicted parts

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    Activity in the primary visual cortex reduces when certain stimuli can be perceptually organized as a unified Gestalt. This reduction could offer important insights into the nature of feedback computations within the human visual system; however, the properties of this response reduction have not yet been investigated in detail. Here we replicate this reduced V1 response, but find that the modulation in V1 (and V2) to the perceived organization of the input is not specific to the retinotopic location at which the sensory input from that stimulus is represented. Instead, we find a response modulation that is equally evident across the primary visual cortex. Thus in contradiction to some models of hierarchical predictive coding, the perception of an organized Gestalt causes a broad feedback effect that does not act specifically on the part of the retinotopic map representing the sensory input

    The brand-personality of three categories of drinks in Australia

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    This study focuses on the 42 traits of brand personality (Aaker 1997) of nine drink brands spanning across three drink segments - fizzy drink, mineral water and energy drink, and measure the congruity of the brands' personalities (five dimension) to the consumer (drinker) of those brands. Based on the results, excitement is the point-of-parity for fizzy drink and energy drink while sincerity is the point-of-parity for mineral water. Other four brand personalities can become the point-of-difference for each brand in each drink category. Using these results, a better understanding of brand personalities of each brand in customer minds can be used to improve marketing communication more effectively and give the right message to the right target market. Future research should be done on such fields and sectors as restaurants, food, other fast moving consumer goods and the like and include a wider sample audience, spanning across different geographical borders. Implication for conceptual, methodological and managerial also discussed in this study

    Sex-specific developmental plasticity in response to yolk corticosterone in an oviparous lizard

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    Corticosterone exposure during prenatal development as a result of maternal upregulation of circulating hormone levels has been shown to have effects on offspring development in mammals. Corticosterone has also been documented in egg yolk in oviparous vertebrates, but the extent to which this influences phenotypic development is less studied. We show that maternal corticosterone is transferred to egg yolk in an oviparous lizard (the mallee dragon, Ctenophorus fordi Storr), with significant variation among clutches in hormone levels. Experimental elevation of yolk corticosterone did not affect hatching success, incubation period or offspring sex ratio. However, corticosterone did have a sex-specific effect on skeletal growth during embryonic development. Male embryos exposed to relatively high levels of corticosterone were smaller on average than control males at hatching whereas females from hormone-treated eggs were larger on average than control females. The data thus suggest that males are not just more sensitive to the detrimental effects of corticosterone but rather that the sexes may have opposite responses to corticosterone during development. Positive selection on body size at hatching for both sexes in this species further suggests that increased corticosterone in egg yolk may have sex-specific fitness consequences, with potential implications for sex allocation and the evolution of hormone-mediated maternal effects.<br /

    Is neuroimaging measuring information in the brain?

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    Psychology moved beyond the stimulus response mapping of behaviorism by adopting an information processing framework. This shift from behavioral to cognitive science was partly inspired by work demonstrating that the concept of information could be defined and quantified (Shannon, 1948). This transition developed further from cognitive science into cognitive neuroscience, in an attempt to measure information in the brain. In the cognitive neurosciences, however, the term information is often used without a clear definition. This paper will argue that, if the formulation proposed by Shannon is applied to modern neuroimaging, then numerous results would be interpreted differently. More specifically, we argue that much modern cognitive neuroscience implicitly focuses on the question of how we can interpret the activations we record in the brain (experimenter-as-receiver), rather than on the core question of how the rest of the brain can interpret those activations (cortex-as-receiver). A clearer focus on whether activations recorded via neuroimaging can actually act as information in the brain would not only change how findings are interpreted but should also change the direction of empirical research in cognitive neuroscience.This work was supported by postdoctoral fellowships to LdW and VE from the Research Foundation Flanders (FWO) and long-term structural funding from the Flemish Government (METH/08/02 and METH/14/02) awarded to JW.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.3758/s13423-016-1002-

    The effective conductivity of arrays of squares: large random unit cells and extreme contrast ratios

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    An integral equation based scheme is presented for the fast and accurate computation of effective conductivities of two-component checkerboard-like composites with complicated unit cells at very high contrast ratios. The scheme extends recent work on multi-component checkerboards at medium contrast ratios. General improvement include the simplification of a long-range preconditioner, the use of a banded solver, and a more efficient placement of quadrature points. This, together with a reduction in the number of unknowns, allows for a substantial increase in achievable accuracy as well as in tractable system size. Results, accurate to at least nine digits, are obtained for random checkerboards with over a million squares in the unit cell at contrast ratio 10^6. Furthermore, the scheme is flexible enough to handle complex valued conductivities and, using a homotopy method, purely negative contrast ratios. Examples of the accurate computation of resonant spectra are given.Comment: 28 pages, 11 figures, submitted to J. Comput. Phy

    Differences in Climbing Ability of Cimex lectularius and Cimex hemipterus (Hemiptera: Cimicidae)

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    The climbing abilities of two bed bug species, Cimex lectularius L. and Cimex hemipterus (F.), were determined by evaluating their escape rates from smooth surface pitfall traps using four commercial bed bug monitors (Verifi Bed Bug Detector, ClimbUp Insect Interceptor, BlackOut Bed Bug Detector, and SenSci Volcano Bed Bug Detector). All detectors were used in the absence of lures or attractants. Unlike C. lectularius, adult C. hemipterus were able to escape from all traps. On the other hand, no or a low number nymphs of both species escaped, depending on the evaluated traps. Examination of the vertical friction force of adults of both species revealed a higher vertical friction force in C. hemipterus than in C. lectularius. Scanning electron microscope micrograph observation on the tibial pad of adult bed bugs of C. hemipterus showed the presence of a greater number of tenent hairs on the tibial pad than on that of adult C. lectularius. No tibial pad was found on the fourth and fifth instars of both species. Near the base of the hollow tenent hairs is a glandular epithelium that is better developed in adult C. hemipterus than in adult C. lectularius. This study highlights significant morphological differences between C. lectularius and C. hemipterus, which may have implications in the monitoring and management of bed bug infestations

    Location Estimation Methods for Open, Privacy Preserving Mobile Positioning

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    The future is mobile and location aware. More and more of our gadgets are portable and have an online presence. For our location-aware mobile future to be safe, we need to demand that our privacy and anonymity be protected. Currently, each and every location aware-system or feature requires us to give new people, corporations and entities access to one of our most intimate attributes, our location. The main solutions to ameliorate this have been by cloaking or hiding users from service providers or by moving trust to other "more trustable" parties. We want to minimize the need for trust. Your location is your own, and you should not have to pay with your privacy to determine it. Our focus lies on location estimation services - services that calculate your location based on measurements done on your network equipment - as they are the main drive behind the location-aware future. You can freely choose, discriminate against, and cloak yourself from services asking for your location, whereas removing the ability to determine your own location effectively impedes location awareness. We are interested in producing a freely available, open source, privacy preserving, community sourced, and safe location estimation service that minimizes the need for trust. In this thesis we focus on three things: Designing such a system, testing different ways of estimating locations, and determining the best way of estimating locations for the designed system

    Constraining General Two Higgs Doublet Models by the Evolution of Yukawa Couplings

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    We study how general two Higgs doublet models can be constrained by considering their properties under renormalization group evolution of the Yukawa couplings. We take into account both the appearance of a Landau pole as well as off-diagonal Yukawa couplings leading to flavour changing neutral currents in violation with experimental constraints at the electroweak scale. We find that the latter condition can be used to limit the amount of Z2 symmetry breaking allowed in a given model.Comment: 28 pages, 10 figures, added discussion of evolution from high to low scales, to be published in JHE
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