1,072 research outputs found

    Racial Threat, Urban Conditions and Police Use of Force: Assessing the Direct and Indirect Linkages Across Multiple Urban Areas

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    Traditionally explanations of police use of force have relied on a racial threat perspective. Tests of this perspective, however, typically offer a single indicator of threat (the relative size of the black population) and fail to adequately take into account the complex relationship between racial threat and police use of force. Drawing on racial threat, social disorganization, and police use of force literature, this study hypothesizes that macro-level patterns in police use of force are embedded in the racial and structural composition of cities and the organizational climate of local politics and police departments. The present study examines these relationships using official police use of force data collected in 73 large U.S. cities. Structural equation analyses suggest that structural indicators associated with racial threat and social disorganization/disadvantage impact police use of force indirectly through the influence of police organizational factors. On the other hand, the political climate and the level of social disorganization in urban areas have a direct bearing on the rates of police use of force. The implications of these findings for research and theory on police use of force are discussed

    Huygens' Principle for the Klein-Gordon equation in the de Sitter spacetime

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    In this article we prove that the Klein-Gordon equation in the de Sitter spacetime obeys the Huygens' principle only if the physical mass mm of the scalar field and the dimension n≥2n\geq 2 of the spatial variable are tied by the equation m2=(n2−1)/4m^2=(n^2-1)/4 . Moreover, we define the incomplete Huygens' principle, which is the Huygens' principle restricted to the vanishing second initial datum, and then reveal that the massless scalar field in the de Sitter spacetime obeys the incomplete Huygens' principle and does not obey the Huygens' principle, for the dimensions n=1,3n=1,3, only. Thus, in the de Sitter spacetime the existence of two different scalar fields (in fact, with m=0 and m2=(n2−1)/4m^2=(n^2-1)/4 ), which obey incomplete Huygens' principle, is equivalent to the condition n=3n=3 (in fact, the spatial dimension of the physical world). For n=3n=3 these two values of the mass are the endpoints of the so-called in quantum field theory the Higuchi bound. The value m2=(n2−1)/4m^2=(n^2-1)/4 of the physical mass allows us also to obtain complete asymptotic expansion of the solution for the large time. Keywords: Huygens' Principle; Klein-Gordon Equation; de Sitter spacetime; Higuchi Boun

    New Insights into Amino Acid Preservation in the Early Oceans Using Modern Analytical Techniques

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    Protein- and non-protein-amino acids likely occupied the oceans at the time of the origin and evolution of life. Primordial soup-, hydrothermal vent-, and meteoritic-processes likely contributed to this early chemical inventory. Prebiotic synthesis and carbonaceous meteorite studies suggest that non-protein amino acids were likely more abundant than their protein-counterparts. Amino acid preservation before abiotic and biotic destruction is key to biomarker availability in paleoenvironments and remains an important uncertainty. To constrain primitive amino acid lifetimes, a 1992 archived seawater/beach sand mixture was spiked with D,L-alanine, D,L-valine (Val), alpha-aminoisobutyric acid (alpha-AIB), D,L-isovaline (Iva), and glycine (Gly). Analysis by high performance liquid chromatography with fluorescence detection (HPLC-FD) showed that only D-Val and non-protein amino acids were abundant after 2250 days. The mixture was re-analyzed in 2012 using HPLC-FD and a triple quadrupole mass spectrometer (QqQ-MS). The analytical results 20 years after the inception of the experiment were strikingly similar to those after 2250 days. To confirm that viable microorganisms were still present, the mixture was re-spiked with Gly in 2012. Aliquots were collected immediately after spiking, and at 5- and 9-month intervals thereafter. Final HPLC-FD/QqQ-MS analyses were performed in 2014. The 2014 analyses revealed that only alpha-AIB, D,L-Iva, and D-Val remained abundant. The disappearance of Gly indicated that microorganisms still lived in the mixture and were capable of consuming protein amino acids. These findings demonstrate that non-protein amino acids are minimally impacted by biological degradation and thus have very long lifetimes under these conditions. Primitive non-protein amino acids from terrestrial synthesis, or meteorite in-fall, likely experienced great-er preservation than protein amino acids in paleo-oceanic environments. Such robust molecules may have reached a steady state concentration dependent on ocean circulation through hydrothermal systems and synthetic input processes. We are presently trying to estimate this concentration

    Plasma anandamide concentrations are lower in children with autism spectrum disorder

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    Background: Autism spectrum disorder (ASD) is a neurodevelopmentaldisorder characterized by restricted, stereotyped behaviors and impairments in social communication. Although the underlying biological mechanisms of ASD remain poorly understood, recent preclinical research has implicated the endogenous cannabinoid (or endocannabinoid), anandamide, as a significant neuromodulator in rodent models of ASD. Despite this promising preclinical evidence, no clinical studies to date have tested whether endocannabinoids are dysregulated in individuals with ASD. Here, we addressed this critical gap in knowledge by optimizing liquid chromatography-tandem mass spectrometry methodology to quantitatively analyze anandamide concentrations in banked blood samples collected from a cohort of children withand without ASD (N= 112). Findings: Anandamide concentrations significantly differentiated ASD cases (N= 59) from controls (N= 53), such that children with lower anandamide concentrations were more likely to have ASD (p= 0.041). In keeping with this notion, anandamide concentrations were also significantly lower in ASD compared to control children (p= 0.034). Conclusions: These findings are the first empirical human data to translate preclinical rodent findings to confirm a link between plasma anandamide concentrations in children with ASD. Although preliminary, these data suggest that impaired anandamide signaling may be involved in the pathophysiology of ASD

    Observational and Modeling Analysis of Land–Atmopshere Coupling over Adjacent Irrigated and Rainfed Cropland during the GRAINEX Field Campaign

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    The Great Plains Irrigation Experiment (GRAINEX) was conducted in the spring and summer of 2018 to investigate Land-Atmosphere (L-A) coupling just prior to and through the growing season across adjacent, but distinctly unique, soil moisture regimes (contrasting irrigated and rainfed fields). GRAINEX was uniquely designed for the development and analysis of an extensive observational dataset for comprehensive process studies of L-A coupling, by focusing on irrigated and rainfed croplands in a ~100 x 100 km domain in southeastern Nebraska. Observation platforms included multiple NCAR EOL Integrated Surface Flux Systems and Integrated Sounding Systems, NCAR CSWR Doppler Radar on Wheels, 1200 radiosonde balloon launches from 5 sites, the NASA GREX airborne L-Band radiometer, and 75 University of Alabama-Huntsville Environmental Monitoring Economic Monitoring Sensor Hubs (EMESH mesonet stations). An integrated observational and modeling approach to advance knowledge of L-A coupling processes and precipitation impacts in regions of heterogeneous soil moisture will be presented. Specifically, through observation of land surface states, surface fluxes, near surface meteorology, and properties of the atmospheric column, an examination of the diurnal planetary boundary layer evolving characteristics will be presented. Results from a hierarchy of modeling platforms (e.g. single column, large-eddy, and mesoscale simulations) will also be presented to complement the observational findings. The modeling effort will generate high spatiotemporal resolution datasets to: 1) generate a multi-physics ensemble to test the robustness and potentially advance physical parameterizations in high resolution weather and climate models, 2) comparison of prescribed forcing from observations and those from offline land surface model simulations and high resolution operational analyses, 3) determine the ability of model simulations to reproduce observed boundary layer evolution, with particular attention to the processes that compose the L-A coupling chain and metrics (e.g. mixing ratio diagrams), and 4) in combination with observations, isolate the impacts of soil moisture heterogeneity on planetary boundary layer characteristics, cloud development, precipitation, mesoscale circulation patters and boundary layer development. Initial results from the observational and modeling analysis will be presented

    Treg depletion potentiates checkpoint inhibition in claudin-low breast cancer

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    Claudin-low breast cancer is an aggressive subtype that confers poor prognosis and is found largely within the clinical triple-negative group of breast cancer patients. Here, we have shown that intrinsic and immune cell gene signatures distinguish the claudin-low subtype clinically as well as in mouse models of other breast cancer subtypes. Despite adaptive immune cell infiltration in claudin-low tumors, treatment with immune checkpoint inhibitory antibodies against cytotoxic T lymphocyte–associated protein 4 (CTLA-4) and programmed death receptor 1 (PD-1) were ineffective in controlling tumor growth. CD4+FoxP3+ Tregs represented a large proportion of the tumor-infiltrating lymphocytes (TILs) in claudin-low tumors, and Tregs isolated from tumor-bearing mice were able to suppress effector T cell responses. Tregs in the tumor microenvironment highly expressed PD-1 and were recruited partly through tumor generation of the chemokine CXCL12. Antitumor efficacy required stringent Treg depletion combined with checkpoint inhibition; delays in tumor growth were not observed using therapies that modestly diminished the number of Tregs in the tumor microenvironment. This study provides evidence that the recruitment of Tregs to the tumor microenvironment inhibits an effective antitumor immune response and highlights early Treg recruitment as a possible mechanism for the lack of response to immune checkpoint blockade antibodies in specific subtypes of cancer that are heavily infiltrated with adaptive immune cells

    Classification and risk stratification of invasive breast carcinomas using a real-time quantitative RT-PCR assay

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    INTRODUCTION: Predicting the clinical course of breast cancer is often difficult because it is a diverse disease comprised of many biological subtypes. Gene expression profiling by microarray analysis has identified breast cancer signatures that are important for prognosis and treatment. In the current article, we use microarray analysis and a real-time quantitative reverse-transcription (qRT)-PCR assay to risk-stratify breast cancers based on biological 'intrinsic' subtypes and proliferation. METHODS: Gene sets were selected from microarray data to assess proliferation and to classify breast cancers into four different molecular subtypes, designated Luminal, Normal-like, HER2+/ER-, and Basal-like. One-hundred and twenty-three breast samples (117 invasive carcinomas, one fibroadenoma and five normal tissues) and three breast cancer cell lines were prospectively analyzed using a microarray (Agilent) and a qRT-PCR assay comprised of 53 genes. Biological subtypes were assigned from the microarray and qRT-PCR data by hierarchical clustering. A proliferation signature was used as a single meta-gene (log(2 )average of 14 genes) to predict outcome within the context of estrogen receptor status and biological 'intrinsic' subtype. RESULTS: We found that the qRT-PCR assay could determine the intrinsic subtype (93% concordance with microarray-based assignments) and that the intrinsic subtypes were predictive of outcome. The proliferation meta-gene provided additional prognostic information for patients with the Luminal subtype (P = 0.0012), and for patients with estrogen receptor-positive tumors (P = 3.4 × 10(-6)). High proliferation in the Luminal subtype conferred a 19-fold relative risk of relapse (confidence interval = 95%) compared with Luminal tumors with low proliferation. CONCLUSION: A real-time qRT-PCR assay can recapitulate microarray classifications of breast cancer and can risk-stratify patients using the intrinsic subtype and proliferation. The proliferation meta-gene offers an objective and quantitative measurement for grade and adds significant prognostic information to the biological subtypes

    Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin.

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    An accurate and precisely annotated genome assembly is a fundamental requirement for functional genomic analysis. Here, the complete DNA sequence and gene annotation of mouse Chromosome 11 was used to test the efficacy of large-scale sequencing for mutation identification. We re-sequenced the 14,000 annotated exons and boundaries from over 900 genes in 41 recessive mutant mouse lines that were isolated in an N-ethyl-N-nitrosourea (ENU) mutation screen targeted to mouse Chromosome 11. Fifty-nine sequence variants were identified in 55 genes from 31 mutant lines. 39% of the lesions lie in coding sequences and create primarily missense mutations. The other 61% lie in noncoding regions, many of them in highly conserved sequences. A lesion in the perinatal lethal line l11Jus13 alters a consensus splice site of nucleoredoxin (Nxn), inserting 10 amino acids into the resulting protein. We conclude that point mutations can be accurately and sensitively recovered by large-scale sequencing, and that conserved noncoding regions should be included for disease mutation identification. Only seven of the candidate genes we report have been previously targeted by mutation in mice or rats, showing that despite ongoing efforts to functionally annotate genes in the mammalian genome, an enormous gap remains between phenotype and function. Our data show that the classical positional mapping approach of disease mutation identification can be extended to large target regions using high-throughput sequencing

    Better Outcomes for Older people with Spinal Trouble (BOOST) Trial: a randomised controlled trial of a combined physical and psychological intervention for older adults with neurogenic claudication, a protocol

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    Introduction Neurogenic claudication due to spinal stenosis is common in older adults. The effectiveness of conservative interventions is not known. The aim of the study is to estimate the clinical and cost-effectiveness of a physiotherapist-delivered, combined physical and psychological intervention. Methods and analysis This is a pragmatic, multicentred, randomised controlled trial. Participants are randomised to a combined physical and psychological intervention (Better Outcomes for Older people with Spinal Trouble (BOOST) programme) or best practice advice (control). Community-dwelling adults, 65 years and over, with neurogenic claudication are identified from community and secondary care services. Recruitment is supplemented using a primary care-based cohort. Participants are registered prospectively and randomised in a 2:1 ratio (intervention:control) using a web-based service to ensure allocation concealment. The target sample size is a minimum of 402. The BOOST programme consists of an individual assessment and twelve 90 min classes, including education and discussion underpinned by cognitive behavioural techniques, exercises and walking circuit. During and after the classes, participants undertake home exercises and there are two support telephone calls to promote adherence with the exercises. Best practice advice is delivered in one to three individual sessions with a physiotherapist. The primary outcome is the Oswestry Disability Index at 12 months. Secondary outcomes include the 6 Minute Walk Test, Short Physical Performance Battery, Fear Avoidance Beliefs Questionnaire and Gait Self-Efficacy Scale. Outcomes are measured at 6 and 12 months by researchers who are masked to treatment allocation. The primary statistical analysis will be by ‘intention to treat’. There is a parallel health economic evaluation and qualitative study

    Genetic regulatory signatures underlying islet gene expression and type 2 diabetes

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    The majority of genetic variants associated with type 2 diabetes (T2D) are located outside of genes in noncoding regions that may regulate gene expression in disease-relevant tissues, like pancreatic islets. Here, we present the largest integrated analysis to date of high-resolution, high-throughput human islet molecular profiling data to characterize the genome (DNA), epigenome (DNA packaging), and transcriptome (gene expression). We find that T2D genetic variants are enriched in regions of the genome where transcription Regulatory Factor X (RFX) is predicted to bind in an islet-specific manner. Genetic variants that increase T2D risk are predicted to disrupt RFX binding, providing a molecular mechanism to explain how the genome can influence the epigenome, modulating gene expression and ultimately T2D risk
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