1,681 research outputs found

    Perceptual “Read-Out” of Conjoined Direction and Disparity Maps in Extrastriate Area MT

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    Cortical neurons are frequently tuned to several stimulus dimensions, and many cortical areas contain intercalated maps of multiple variables. Relatively little is known about how information is “read out” of these multidimensional maps. For example, how does an organism extract information relevant to the task at hand from neurons that are also tuned to other, irrelevant stimulus dimensions? We addressed this question by employing microstimulation techniques to examine the contribution of disparity-tuned neurons in the middle temporal (MT) visual area to performance on a direction discrimination task. Most MT neurons are tuned to both binocular disparity and the direction of stimulus motion, and MT contains topographic maps of both parameters. We assessed the effect of microstimulation on direction judgments after first characterizing the disparity tuning of each stimulation site. Although the disparity of the stimulus was irrelevant to the required task, we found that microstimulation effects were strongly modulated by the disparity tuning of the stimulated neurons. For two of three monkeys, microstimulation of nondisparity-selective sites produced large biases in direction judgments, whereas stimulation of disparity-selective sites had little or no effect. The binocular disparity was optimized for each stimulation site, and our result could not be explained by variations in direction tuning, response strength, or any other tuning property that we examined. When microstimulation of a disparity-tuned site did affect direction judgments, the effects tended to be stronger at the preferred disparity of a stimulation site than at the nonpreferred disparity, indicating that monkeys can selectively monitor direction columns that are best tuned to an appropriate conjunction of parameters. We conclude that the contribution of neurons to behavior can depend strongly upon tuning to stimulus dimensions that appear to be irrelevant to the current task, and we suggest that these findings are best explained in terms of the strategy used by animals to perform the task

    Systemic Racism in Police Killings: New Evidence From the Mapping Police Violence Database, 2013–2021

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    This research note provides new evidence consistent with systemic anti-Black racism in police killings across the United States. Data come from the Mapping Police Violence Database (2013–2021). I calculate race-specific odds and probabilities that victims of police killings exhibited mental illness, were armed with a weapon, or attempted to flee the scene at the time of their killing. Multilevel, multivariable logistic regression techniques are applied to further account for the victim's age, gender, year of killing, and geographical clustering. I find that White victims are underrepresented, and Black victims overrepresented in the database. Relative to White victims, Black victims also have 60% lower odds of exhibiting signs of mental illness, 23% lower odds of being armed, and 28% higher odds of fleeing. Hispanic victims exhibit 45% lower odds of being armed relative to their White peers but are otherwise comparable. These patterns persist regardless of the victim's age, gender, year of killing, or geographical location (state, zip code, and neighborhood type). Thus, the threshold for being perceived as dangerous, and thereby falling victim to lethal police force, appears to be higher for White civilians relative to their Black or Hispanic peers. Current findings provide empirical support for political initiatives to curb lethal police force, as such efforts could help to reduce racial disparities in deaths by police nationwide

    Separable time-causal and time-recursive spatio-temporal receptive fields

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    We present an improved model and theory for time-causal and time-recursive spatio-temporal receptive fields, obtained by a combination of Gaussian receptive fields over the spatial domain and first-order integrators or equivalently truncated exponential filters coupled in cascade over the temporal domain. Compared to previous spatio-temporal scale-space formulations in terms of non-enhancement of local extrema or scale invariance, these receptive fields are based on different scale-space axiomatics over time by ensuring non-creation of new local extrema or zero-crossings with increasing temporal scale. Specifically, extensions are presented about parameterizing the intermediate temporal scale levels, analysing the resulting temporal dynamics and transferring the theory to a discrete implementation in terms of recursive filters over time.Comment: 12 pages, 2 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:1404.203

    The transcriptional response of soil bacteria to long-term warming and short-term seasonal fluctuations in a terrestrial forest

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chowdhury, P. R., Golas, S. M., Alteio, L., Stevens, J. T. E., Billings, A. F., Blanchard, J. L., Melillo, J. M., & DeAngelis, K. M. The transcriptional response of soil bacteria to long-term warming and short-term seasonal fluctuations in a terrestrial forest. Frontiers in Microbiology, 12, (2021): 666558, https://doi.org/10.3389/fmicb.2021.666558.Terrestrial ecosystems are an important carbon store, and this carbon is vulnerable to microbial degradation with climate warming. After 30 years of experimental warming, carbon stocks in a temperate mixed deciduous forest were observed to be reduced by 30% in the heated plots relative to the controls. In addition, soil respiration was seasonal, as was the warming treatment effect. We therefore hypothesized that long-term warming will have higher expressions of genes related to carbohydrate and lipid metabolism due to increased utilization of recalcitrant carbon pools compared to controls. Because of the seasonal effect of soil respiration and the warming treatment, we further hypothesized that these patterns will be seasonal. We used RNA sequencing to show how the microbial community responds to long-term warming (~30 years) in Harvard Forest, MA. Total RNA was extracted from mineral and organic soil types from two treatment plots (+5°C heated and ambient control), at two time points (June and October) and sequenced using Illumina NextSeq technology. Treatment had a larger effect size on KEGG annotated transcripts than on CAZymes, while soil types more strongly affected CAZymes than KEGG annotated transcripts, though effect sizes overall were small. Although, warming showed a small effect on overall CAZymes expression, several carbohydrate-associated enzymes showed increased expression in heated soils (~68% of all differentially expressed transcripts). Further, exploratory analysis using an unconstrained method showed increased abundances of enzymes related to polysaccharide and lipid metabolism and decomposition in heated soils. Compared to long-term warming, we detected a relatively small effect of seasonal variation on community gene expression. Together, these results indicate that the higher carbohydrate degrading potential of bacteria in heated plots can possibly accelerate a self-reinforcing carbon cycle-temperature feedback in a warming climate.Funding for this study was provided by the Department of Energy Terrestrial Ecosystem Sciences program under contract number DE-SC0010740. Sites for sample collection were maintained with funding in part from the National Science Foundation (NSF) Long-Term Ecological Research (DEB 1237491) and the NSF Long-Term Research in Environmental Biology (DEB 1456528) programs

    Disclosing conflicts of interest in German publications concerning health services research

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    <p>Abstract</p> <p>Background</p> <p>The influence of the pharmaceutical industry and other stakeholders on medical science has been increasingly criticised. When dealing with conflicts of interest in scientific publications it is important to ensure the best possible transparency. The objective of this work is to examine the disclosure practice of financial and non-financial conflicts of interest in German language publications concerning health services research for the first time.</p> <p>Methods</p> <p>We performed a systematic literature search in the PubMed data base using the MeSH term "health services research". The review was conducted on July 10, 2006, setting the limits "dates: published in the last 2 years" and "languages: German" (only articles with abstracts). 124 articles in 31 magazines were found. In the magazines the instructions for authors were examined as to whether a statement on conflicts of interest is expected – and if, in which form. Regarding the articles in the journals which require a statement, we examined whether the statement is explicitly published. The results are descriptively represented.</p> <p>Results</p> <p>13 magazines (42%) do not require any statement on conflicts of interest, whereas 18 journals (58%) expect a statement. Two of these 18 magazines refer explicitly to the uniform requirements of the <it>International Committee of the Medical Journal Editors </it>(ICMJE); the remaining 16 magazines give differently accentuated instructions on how to disclose conflicts of interest, whereby the focus is primarily on financial issues. A statement on conflicts of interest is explicitly published in 11 of the 71 articles (15%) which are found in the magazines that require a statement with the submission of a manuscript. Related to the total number of included articles, this means that the reader explicitly receives information on potential conflicts of interest in 9% of the cases (11 of 124 articles). Statements of others that are involved in the publication process (reviewers, editors) are not available in any of the articles examined.</p> <p>Conclusion</p> <p>A better sensitization for possible conflicts of interest in German publications concerning health services research is necessary. We suggest tightening the criteria for disclosure in the instructions for authors in the scientific journals. Among other things the equivalent consideration of financial and non-financial conflicts of interest as well as the obligatory publication of the statements should be part of good practice.</p

    Historical Neighborhood Redlining

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    The source data used to construct this contextual file for the National Longitudinal Study of Adolescent to Adult Health (Add Health) come from Mapping Inequality: Redlining in New Deal America, compiled by Robert K. Nelson and the Digital Scholarship Lab at the University of Richmond. This file augments the current Add Health contextual data collection by providing information about whether a respondent’s place of residence falls inside or within varying proximities to historically redlined neighborhood boundaries at the time of their Wave I, III, IV, and V survey interviews. This contextual database allows researchers to identify potential long-term consequences of redlining for contemporary inequities in neighborhood environments, and individual health and socioeconomic attainment over the life course. Before analyzing these data, however, we urge users to review the following background section and cited references

    Properties of 12^{12}C in the {\it ab initio} nuclear shell-model

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    We obtain properties of 12^{12}C in the {\it ab initio} no-core nuclear shell-model. The effective Hamiltonians are derived microscopically from the realistic CD-Bonn and the Argonne V8' nucleon-nucleon (NN) potentials as a function of the finite harmonic oscillator basis space. Binding energies, excitation spectra and electromagnetic properties are presented for model spaces up to 5ℏΩ5\hbar\Omega. The favorable comparison with available data is a consequence of the underlying NN interaction rather than a phenomenological fit.Comment: 9 pages, 2 figure
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