30,519 research outputs found

    Does binding of synesthetic color to the evoking grapheme require attention?

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    The official published version can be accessed from the link below.The neural mechanisms involved in binding features such as shape and color are a matter of some debate. Does accurate binding rely on spatial attention functions of the parietal lobe or can it occur without attentional input? One extraordinary phenomenon that may shed light on this question is that of chromatic-graphemic synesthesia, a rare condition in which letter shapes evoke color perceptions. A popular suggestion is that synesthesia results from cross-activation between different functional regions (e.g., between shape and color areas of the ventral pathway). Under such conditions binding may not require parietal involvement and could occur preattentively. We tested this hypothesis in two synesthetes who perceived grayscale letters and digits in color. We found no evidence for preattentive binding using a visual search paradigm in which the target was a synesthetic inducer. In another experiment involving color judgments, we show that the congruency of target color and the synesthetic color of irrelevant digits modulates performance more when the digits are included within the attended region of space. We propose that the mechanisms giving rise to this type of synesthesia appear to follow at least some principles of normal binding, and even synesthetic binding seems to require attention.This work has been supported by a Veterans Administration Senior Research Career Scientist Award and NINDS grant #MH62331 to LCR and the Elizabeth Roboz Einstein fellowship in Neuroscience and Human Development to NS

    Total plankton respiration in the Chesapeake Bay plume

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    Total plankton respiration (TPR) was measured at 17 stations within the Chesapeake Bay plume off the Virginia coast during March, June, and October 1980. Elevated rates of TPR, as well as higher concentrations of chlorophyll a and phaeopigment a, were found to be associated with the Bay plume during each survey. The TPR rates within the Bay plume were close to those found associated with the Hudson River plume for comparable times of the year. The data examined indicate that the Chesapeake Bay plume stimulates biological activity and is a source of organic loading to the contiguous shelf ecosystem

    Phonon contributions to the entropies of hP24 and fcc Co3V

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    Inelastic neutron-scattering spectra and neutron-diffraction patterns were measured on the alloy Co3V at temperatures from 1073-1513 K, where the hP24 (ordered hexagonal) and fee structures are the equilibrium states of the alloy. Phonon density of states (DOS) curves were calculated from the inelastic-scattering spectra, allowing estimates of the vibrational entropy in the harmonic and quasiharmonic approximations. The vibrational entropy of the hP24-fcc phase transition at 1323 K was found to be 0.07k(B)/atom. The anharmonic contributions to the entropy over a temperature range of 100 K were comparable to the vibrational entropy of this phase transition. The anharmonic softening of the phonon DOS was only slightly larger for the hP24 than the fee phase, however, so the anharmonic effects contribute only slightly to the difference in entropy of the two phases. The simple Gruneisen approximation was inadequate for predicting the thermal softening of the phonon DOS

    Entrepreneurs'' attitude towards the computer and its effect on e-business adoption

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    This paper presents research exploring further the concept that many SMEs do not adopt computer based technologies due to decision maker's negative attitudes towards computers generally. Importantly, by assessing the entrepreneur's belief structure, we provide quantitative evidence how SMEs, particularly micros, are affected. Earlier research that addresses technology acceptance model (TAM) suggests that TAM parameters are particularly influential factors of e-commerce adoption, as perceived by top managers of SMEs. The model we develop is tested using a sample of 655 enterprises. The information was gathered, via a telephone survey of UK SMEs, from decisions makers in the enterprise. Technically, the paper uses k-means cluster analysis to segment respondents using the TAM perceptions, ease of use, usefulness and enjoyment. Based on two determined segments we look at the differential rate of adoption of internet, and the potential adoption of new e-collaborative technologies like video conferencing and electronic whiteboards. The diffusion of internet for low IT utility (LIT) segments was considerably slower than in the high utility segment (HIT). Similarly, the anticipated adoption of e-collaboration technologies was much lower for LIT than HIT. Interestingly, we find that LIT is populated by more micro SMEs than HIT. The results we present are limited however as our sample is considerably underweight in micro SMEs, suggesting that the problem may be much larger in the economy than our model predicts. For policy makers, this research confirms the value of knowledge transfer programs to SMEs in the form of technology support. Our research shows that organisations which have dedicated IT support will tend to be more advanced technologically than those that do not. The implication for entrepreneurs is if they can be persuaded that a technological route is beneficial to them, and that suitable support can be provided via KT, then operational efficiency gains could be made. This paper contributes to knowle

    A small angle neutron scattering and Mössbauer spectrometry study of magnetic structures in nanocrystalline Ni3Fe

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    Results are reported from small angle neutron scattering and Mössbauer spectrometry measurements on nanocrystalline Ni3Fe. The nanocrystalline materials were prepared by mechanical attrition and studied in the as-milled state, after annealing at 265 °C to relieve internal stress, and after annealing 600 °C to prepare a control sample comprising large crystals. The small angle neutron scattering (SANS) measurements were performed for a range of applied magnetic fields. Small differences were found in how the different samples reached magnetic saturation. From the SANS data obtained at magnetic saturation, we found little difference in the nuclear scattering of the as-milled material and the material annealed at 265 °C. Reductions in nuclear scattering and magnetic scattering were observed for the control sample, and this was interpreted as grain growth. The material annealed at 265 °C also showed a reduction in magnetic SANS compared to the as-milled material. This was interpreted as an increase in magnetic moments of atoms at the grain boundaries after a low temperature annealing. Both Mössbauer spectroscopy and small angle neutron scattering showed an increase in the grain boundary magnetic moments after the 265 °C annealing (0.2 and 0.4µB/atom, respectively), even though there was little change in the grain boundary atomic density

    The search for innovators and early adopters of e-collaborative technologies within small and medium sized enterprises in the UK

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    New product diffusion theory predicts that innovators and early adopters are critical to the success of new innovations. The rate at which enterprises adopt e-Science technologies must therefore rely upon reliable market intelligence so that the critical early stages of adoption are successfully navigated by developers and planners. Failure to understand attitudes towards new technologies can lead to even useful technologies being under-adopted. This paper applies a survey based methodology to develop estimates of demand for web based virtual Collaborative technologies. We show that approximately 76% of the 1029 firms that we interviewed are technologically ready to deploy these technologies. We also show that 10% of all firms are ready look at these technologies as solutions to collaborative problem solving

    Passive and active seismic isolation for gravitational radiation detectors and other instruments

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    Some new passive and active methods for reducing the effects of seismic disturbances on suspended masses are described, with special reference to gravitational radiation detectors in which differential horizontal motions of two or more suspended test masses are monitored. In these methods it is important to be able to determine horizontal seismic accelerations independent of tilts of the ground. Measurement of changes in inclination of the suspension wire of a test mass, relative to a direction defined by a reference arm of long period of oscillation, makes it possible to carry this out over the frequency range of interest for earth-based gravitational radiation detectors. The signal obtained can then be used to compensate for the effects of seismic disturbances on the test mass if necessary. Alternatively the signal corresponding to horizontal acceleration can be used to move the point from which the test mass is suspended in such a way as to reduce the effect of the seismic disturbance and also damp pendulum motions of the suspended test mass. Experimental work with an active anti-seismic system of this type is described

    Superflux chlorophyll-a analysis: An assessment of variability in results introduced prior to fluorometric analysis

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    Several experiments were undertaken to identify variability in results that came from procedural differences in the processing of chlorophyll samples prior to fluorometric analysis. T-tests on group means indicated that significant differences (alpha = 0.05) in phaeopigment a concentrations did result in samples not initially screened, but not in the chlorophyll a concentrations. Highly significant differences (alpha = 0.001) in group means were found in samples which were held in acetone after filtering as compared to unfiltered seawater samples held for the same period. No difference in results was found between the 24-hour extraction and samples which were processed immediately

    Scotin, a novel p53-inducible proapoptotic protein located in the ER and the nuclear membrane

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    p53 is a transcription factor that induces growth arrest or apoptosis in response to cellular stress. To identify new p53-inducible proapoptotic genes, we compared, by differential display, the expression of genes in spleen or thymus of normal and p53 nullizygote mice after Îł-irradiation of whole animals. We report the identification and characterization of human and mouse Scotin homologues, a novel gene directly transactivated by p53. The Scotin protein is localized to the ER and the nuclear membrane. Scotin can induce apoptosis in a caspase-dependent manner. Inhibition of endogenous Scotin expression increases resistance to p53-dependent apoptosis induced by DNA damage, suggesting that Scotin plays a role in p53-dependent apoptosis. The discovery of Scotin brings to light a role of the ER in p53-dependent apoptosis
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