5,214 research outputs found

    False discovery rate regression: an application to neural synchrony detection in primary visual cortex

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    Many approaches for multiple testing begin with the assumption that all tests in a given study should be combined into a global false-discovery-rate analysis. But this may be inappropriate for many of today's large-scale screening problems, where auxiliary information about each test is often available, and where a combined analysis can lead to poorly calibrated error rates within different subsets of the experiment. To address this issue, we introduce an approach called false-discovery-rate regression that directly uses this auxiliary information to inform the outcome of each test. The method can be motivated by a two-groups model in which covariates are allowed to influence the local false discovery rate, or equivalently, the posterior probability that a given observation is a signal. This poses many subtle issues at the interface between inference and computation, and we investigate several variations of the overall approach. Simulation evidence suggests that: (1) when covariate effects are present, FDR regression improves power for a fixed false-discovery rate; and (2) when covariate effects are absent, the method is robust, in the sense that it does not lead to inflated error rates. We apply the method to neural recordings from primary visual cortex. The goal is to detect pairs of neurons that exhibit fine-time-scale interactions, in the sense that they fire together more often than expected due to chance. Our method detects roughly 50% more synchronous pairs versus a standard FDR-controlling analysis. The companion R package FDRreg implements all methods described in the paper

    Lost Gems: Identifying Rare and Unusual Monographs in a University\u27s Circulating Collection

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    Identifying and evaluating the oldest published content held by the library using a set of transfer criteria provided a means to systematically evaluate and, if necessary, move rare or unusual content into a more secure location. The process enabled us to correct cataloging errors, identify and address items with condition issues, be familiar with the library\u27s unique holdings and finally, to identify and add content distinctly associated with EMU\u27s history to the University Archives and Special Collections

    Contributor to the November Issue/Notes

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    Notes by Charles G. Hasson, Robert J. Mahoney, Robert E. Sullivan, John Kelly, John D. O\u27Neill, John M. Anderton, Charles R. Gerard, R. A. Macdonell, William B. Ball, Robert E. Sullivan, and Leonard D. Bodkin

    Determination of the Corrosive Conditions Present within Aircraft Lap-Splice Joints

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    The complexity of airframe structure lends itself to damage resulting from crevice corrosion. Fuselage lap-splice joints are a particularly important structural detail in this regard because of the difficulty associated with detection and measurement of corrosion in these occluded regions. The objective of this work is to develop a laboratory corrosion test protocol to identify the chemistry to which lap joints are exposed and to develop a model of the corrosion within the joints. A protocol for collecting and identifying the chemistry of airframe crevice corrosion has been developed. Capillary electrophoresis (CE) is used to identify the ionic species contained in corrosion product samples removed from fuselage lap splice joints. CE analysis has been performed on over sixty corrosion product samples removed from both civilian and military aircraft. Over twenty different ions have been detected. Measurements of pH of wetted corroded surfaces indicated an alkaline occluded solution. After determining the species present and their relative concentrations, the resultant solution was reproduced in bulk and electrochemical tests were performed to determine the corrosion rate. Electrochemical analyses of the behavior of AA2024-T3 in these solutions gave corrosion rates of up to 250 microns per year (10 mpy). Additional tests have determined the relative importance of each of the detected ions in model solutions used for future predictive tests. The statistically significant ions have been used to create a second generation solution. Laboratory studies have also included exposure tests involving artificial lap joints exposed to various simulated bulk and crevice environments. The extent and morphology of the attack in artificial lap joints has been compared to studies of corroded samples from actual aircraft. Other effects, such as temperature and potential, as well as the impact of the environment on fatigue crack growth have also been studied

    Contributor to the November Issue/Notes

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    Notes by Charles G. Hasson, Robert J. Mahoney, Robert E. Sullivan, John Kelly, John D. O\u27Neill, John M. Anderton, Charles R. Gerard, R. A. Macdonell, William B. Ball, Robert E. Sullivan, and Leonard D. Bodkin

    Exploring Russian Cyberspace: Digitally-Mediated Collective Action and the Networked Public Sphere

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    This paper summarizes the major findings of a three-year research project to investigate the Internet's impact on Russian politics, media and society. We employed multiple methods to study online activity: the mapping and study of the structure, communities and content of the blogosphere; an analogous mapping and study of Twitter; content analysis of different media sources using automated and human-based evaluation approaches; and a survey of bloggers; augmented by infrastructure mapping, interviews and background research. We find the emergence of a vibrant and diverse networked public sphere that constitutes an independent alternative to the more tightly controlled offline media and political space, as well as the growing use of digital platforms in social mobilization and civic action. Despite various indirect efforts to shape cyberspace into an environment that is friendlier towards the government, we find that the Russian Internet remains generally open and free, although the current degree of Internet freedom is in no way a prediction of the future of this contested space

    Introduction of an applicant Job-Related Task Assessment (JTA) and the effects on the health and fitness of police recruits

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    In 2020, a police department in the south-eastern USA introduced a Job-Related Task Assessment (JTA). The JTA included running, climbing, crawling, balance, direction changes, stair climbing, dragging, pushing, and simulated controlling of a struggling subject and needed to be completed by applicants in 6 : 57 min:s. It is not known whether introducing the JTA in the hiring process affected the health and fitness of hired recruits. OBJECTIVE: To compare the health and fitness of recruits hired prior to, and following, the JTA introduction. METHODS: Analysis was conducted on recruit data split into academy training year: 2016 (n = 91), 2017 (n = 129), 2018 (n = 167), 2019 (n = 242), and 2020 (n = 37). The 2020 group was hired after the JTA introduction and included one academy class. The following were recorded for all recruits: age, height, body mass, and body mass index; systolic and diastolic blood pressure (BP); sit-and-reach; grip strength; push-ups; sit-ups; 2.4-km run; and a physical ability test (PAT). A univariate ANOVA, with sex and age as covariates and Bonferroni post hoc, determined between-year differences. RESULTS: The recruits from 2020 were significantly lighter than 2018 recruits (p <  0.031), had higher systolic and diastolic BP than recruits from 2016–2018 (p≤0.006), completed the 2.4-km run faster than recruits from all years (p <  0.001), and completed the PAT faster than the 2016 and 2019 (p = 0.006–0.007) recruits. CONCLUSION: The JTA introduction led to the selection of recruits with lower body mass, and better aerobic (2.4-km run) and job-specific fitness (PAT). However, 2020 recruits also had higher BP which should be monitored

    Integrated Ground Operations Demonstration Units Testing Plans and Status

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    Cryogenic propellant loading operations with their associated flight and ground systems are some of the most complex, critical activities in launch operations. Consequently, these systems and operations account for a sizeable portion of the life cycle costs of any launch program. NASA operations for handling cryogens in ground support equipment have not changed substantially in 50 years, despite advances in cryogenics, system health management and command and control technologies. This project was developed to mature, integrate and demonstrate advancement in the current state of the art in these areas using two distinct integrated ground operations demonstration units (GODU): GODU Integrated Refrigeration and Storage (IRAS) and GODU Autonomous Contro
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