1,609 research outputs found

    Exploiting Structural Complexity for Robust and Rapid Hyperspectral Imaging

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    This paper presents several strategies for spectral de-noising of hyperspectral images and hypercube reconstruction from a limited number of tomographic measurements. In particular we show that the non-noisy spectral data, when stacked across the spectral dimension, exhibits low-rank. On the other hand, under the same representation, the spectral noise exhibits a banded structure. Motivated by this we show that the de-noised spectral data and the unknown spectral noise and the respective bands can be simultaneously estimated through the use of a low-rank and simultaneous sparse minimization operation without prior knowledge of the noisy bands. This result is novel for for hyperspectral imaging applications. In addition, we show that imaging for the Computed Tomography Imaging Systems (CTIS) can be improved under limited angle tomography by using low-rank penalization. For both of these cases we exploit the recent results in the theory of low-rank matrix completion using nuclear norm minimization

    On Overreaching, or Why Rick Perry May Save the Voting Rights Act but Destroy Affirmative Action

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    Abstract The State of Texas is presently staking out two positions that are not typically pursued by a single litigant. On the one hand, Texas is seeking the invalidation of the Voting Rights Act, and, on the other, the State is now defending the validity of the expansive race-based affirmative action policy it uses at its flagship university. This Essay presses the claim that Texas has increased the chance it will lose in both Texas v. Holder and Fisher v. University of Texas because it has opted to stake out markedly extreme positions in each. I argue that Texas would be more likely to succeed had it chosen to temper both its actions and claims in the pending cases. As it stands, Texas's assertive stance in Fisher promises to bolster the aversion many Justices already feel towards affirmative action. With regard to the VRA, however, Texas's uncompromising approach to the regime may prove to be the VRA's best defense. As recent redistricting and voter ID decisions suggest, Texas's stance may be provide what is arguably better evidence for why the statute remains necessary than anything proffered by the VRA's many supporters. Indeed, the State's aggressively hostile stance towards the VRA has the potential to destabilize judicial misgivings about the statute, and, if not fully reverse them, postpone their implementation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98443/1/elj%2E2012%2E1147.pd

    Differential Antigen Presentation Regulates the Changing Patterns of CD8+ T Cell Immunodominance in Primary and Secondary Influenza Virus Infections

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    The specificity of CD8+ T cell responses can vary dramatically between primary and secondary infections. For example, NP366–374/Db- and PA224–233/Db-specific CD8+ T cells respond in approximately equal numbers to a primary influenza virus infection in C57BL/6 mice, whereas NP366–374/Db-specific CD8+ T cells dominate the secondary response. To investigate the mechanisms underlying this changing pattern of immunodominance, we analyzed the role of antigen presentation in regulating the specificity of the T cell response. The data show that both dendritic and nondendritic cells are able to present the NP366–374/Db epitope, whereas only dendritic cells effectively present the PA224–233/Db epitope after influenza virus infection, both in vitro and in vivo. This difference in epitope expression favored the activation and expansion of NP366–374/Db-specific CD8+ memory T cells during secondary infection. The data also show that the immune response to influenza virus infection may involve T cells specific for epitopes, such as PA224–233/Db, that are poorly expressed at the site of infection. In this regard, vaccination with the PA224–233 peptide actually had a detrimental effect on the clearance of a subsequent influenza virus infection. Thus, differential antigen presentation impacts both the specificity of the T cell response and the efficacy of peptide-based vaccination strategies

    Tempo and mode of gene expression evolution in the brain across primates

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    Primate evolution has led to a remarkable diversity of behavioral specializations and pronounced brain size variation among species (Barton, 2012; DeCasien and Higham, 2019; Powell et al., 2017). Gene expression provides a promising opportunity for studying the molecular basis of brain evolution, but it has been explored in very few primate species to date (e.g. Khaitovich et al., 2005; Khrameeva et al., 2020; Ma et al., 2022; Somel et al., 2009). To understand the landscape of gene expression evolution across the primate lineage, we generated and analyzed RNA-seq data from four brain regions in an unprecedented eighteen species. Here, we show a remarkable level of variation in gene expression among hominid species, including humans and chimpanzees, despite their relatively recent divergence time from other primates. We found that individual genes display a wide range of expression dynamics across evolutionary time reflective of the diverse selection pressures acting on genes within primate brain tissue. Using our samples that represent a 190-fold difference in primate brain size, we identified genes with variation in expression most correlated with brain size. Our study extensively broadens the phylogenetic context of what is known about the molecular evolution of the brain across primates and identifies novel candidate genes for the study of genetic regulation of brain evolution

    In-hospital outcomes and 30-day readmission rates among ischemic and hemorrhagic stroke patients with delirium

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    OBJECTIVE: Delirium is associated with poor outcomes among critically ill patients. However, it is not well characterized among patients with ischemic or hemorrhagic stroke (IS and HS). We provide the population-level frequency of in-hospital delirium and assess its association with in-hospital outcomes and with 30-day readmission among IS and HS patients. METHODS: We analyzed Nationwide in-hospital and readmission data for years 2010-2015 and identified stroke patients using ICD-9 codes. Delirium was identified using validated algorithms. Outcomes were in-hospital mortality, length of stay, unfavorable discharge disposition, and 30-day readmission. We used survey design logistic regression methods to provide national estimates of proportions and 95% confidence intervals (CI) for delirium, and odds ratios (OR) for association between delirium and poor outcomes. RESULTS: We identified 3,107,437 stroke discharges of whom 7.45% were coded to have delirium. This proportion significantly increased between 2010 (6.3%) and 2015 (8.7%) (aOR, 95% CI: 1.04, 1.03-1.05). Delirium proportion was higher among HS patients (ICH: 10.0%, SAH: 9.8%) as compared to IS patients (7.0%). Delirious stroke patients had higher in-hospital mortality (12.3% vs. 7.8%), longer in-hospital stay (11.6 days vs. 7.3 days) and a significantly greater adjusted risk of 30-day-readmission (16.7%) as compared to those without delirium (12.2%) (aRR, 95% CI: 1.13, 1.11-1.15). Upon readmission, patients with delirium at initial admission continued to have a longer length of stay (7.7 days vs. 6.6 days) and a higher in-hospital mortality (9.3% vs. 6.4%). CONCLUSION: Delirium identified through claims data in stroke patients is independently associated with poor in-hospital outcomes both at index admission and readmission. Identification and management of delirium among stroke patients provides an opportunity to improve outcomes

    Priority sites for wildfowl conservation in Mexico

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    A set of priority sites for wildfowl conservation in Mexico was determined using contemporary count data (1991–2000) from the U.S. Fish & Wildlife Service mid-winter surveys. We used a complementarity approach implemented through linear integer programming that addresses particular conservation concerns for every species included in the analysis and large fluctuations in numbers through time. A set of 31 priority sites was identified, which held more than 69% of the mid-winter count total in Mexico during all surveyed years. Six sites were in the northern highlands, 12 in the central highlands, six on the Gulf of Mexico coast and seven on the upper Pacific coast. Twenty-two sites from the priority set have previously been identified as qualifying for designation as wetlands of international importance under the Ramsar Convention and 20 sites are classified as Important Areas for Bird Conservation in Mexico. The information presented here provides an accountable, spatially-explicit, numerical basis for ongoing conservation planning efforts in Mexico, which can be used to improve existing wildfowl conservation networks in the country and can also be useful for conservation planning exercises elsewhere

    Identification of intermediates of in vivo trichloroethylene oxidation by the membrane-associated methane monooxygenase

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    The rate and products of trichloroethylene (TCE) oxidation by Methylomicrobium album BG8 expressing membrane-associated methane monooxygenase (pMMO) were determined using 14 C radiotracer techniques. [ 14 C]TCE was degraded at a rate of 1.24 nmol (min mg protein) −1 with the initial production of glyoxylate and then formate. Radiolabeled CO 2 was also found after incubating M. album BG8 for 5 h with [ 14 C]TCE. Experiments with purified pMMO from Methylococcus capsulatus Bath showed that TCE could be mineralized to CO 2 by pMMO. Oxygen uptake studies verified that M. album BG8 could oxidize glyoxylate and that pMMO was responsible for the oxidation based on acetylene inactivation studies. Here we propose a pathway of TCE oxidation by pMMO-expressing cells in which TCE is first converted to TCE-epoxide. The epoxide then spontaneously undergoes HCl elimination to form glyoxylate which can be further oxidized by pMMO to formate and CO 2 .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74667/1/j.1574-6968.2000.tb09090.x.pd

    Racism, anti-racist practice and social work: articulating the teaching and learning experiences of Black social workers

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    In the mid 1990s a Black practice teacher programme was established in Manchester and Merseyside with the primary aim to increase the number of Black practice teachers in social work organisations, and in turn provide a supportive and encouraging learning environment for Black student social workers whilst on placement. In the north‐west of England research has been undertaken, to establish the quality of the practice teaching and student learning taking place with Black practice teachers and students. This paper is an exploration of the ideas generated within the placement process that particularly focused on the discourse of racism and ant‐racist practice. Black students and practice teachers explain their understanding of racism and anti‐racist practice within social work. From the research, the paper will critique some of the ideas concerning anti‐racism. In particular, it will question whether anti‐racist social work practice needs to be re‐evaluated in the light of a context with new migrants, asylum seekers and refugees. It will concluded, by arguing that whilst the terms anti‐racism, Black and Minority Ethnic have resonance as a form of political strategic essentialism, it is important to develop more positive representations in the future
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