291 research outputs found

    Spatial Coherency in Colourisation

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    Automatic colourisation is the function of inferring colour information from a grey-scale prior and then combining the colour with the grey-scale to form a colourised version of the image. We identify Spatial Coherence as a particular weakness in methods that use Convolutional Neural Networks for colourisation. Generated colours do not adhere to semantic edges and are not consistent within boundaries where we would expect uniform colour. Spatial Coherence, while often evident to the human eye, does not yet have an objective metric. We show, by segmentation of the combined ab channels of the CIEL*a*b* colour space, that a segmentation based on CNN colourisation is poor. We argue the need for the development of metrics to evaluate a colourisation’s performance on Spatial Coherence

    A Statistical Analysis of Surface Roughness Influences on Tornadogenesis and Tornado Decay within the Southeastern United States

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    As tornadic activity increases in the Southeastern United States (Agee et al. 2016), it becomes imperative to investigate tornadic activity in this region. Given that patterns of land cover greatly differ between the Southeast and the traditional Tornado Alley and that surface roughness has been well documented to affect the structure and behavior of tornadoes (Bode et al. 1975; Dessens 1972; Kuai et al. 2008; Matsui and Tamura 2009; Natarajan and Hangan 2009, 2012; Neakrase and Greeley 2010; Wang et al. 2017; Zhang and Sarkar 2008), investigating the relationship between surface roughness and tornadic activity in the Southern U.S. would be a worthwhile enterprise. A hotspot analysis of tornadogenesis and tornado decay points, was performed within four states within the region with high tornadic activity (Alabama, Georgia, Mississippi, and Tennessee). Additionally, statistical comparisons of the frequency of tornadogenesis and decay within each of the categories of land cover as defined by the National Land Cover Database (NLCD) were made in each of the four states of study. Finally, the average surface roughness length in the immediate areas surrounding the tornadogenesis and decay points were statistically compared to the surface roughness lengths in the surrounding environments. Results indicated that tornadoes were more likely to form and dissipate in developed areas and at sites in which the average surface roughness greatly differed from the average surface roughness in the immediate environment. While some studies (Cusack 2014) have indicated the potential that urban environments are more likely to produce tornadogenesis, it is impossible to come to a firm conclusion of causation given the possibility of damage indicator reporting bias when it comes to tornado tracks and spatial correlation bias when it comes to land cover analysis.No embargoAcademic Major: Atmospheric Science

    Virology under the microscope-A call for rational discourse

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    Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns - conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we - a broad group of working virologists - seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology

    Factor Xa cleaves SARS-CoV-2 spike protein to block viral entry and infection

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    Serine proteases (SP), including furin, trypsin, and TMPRSS2 cleave the SARS-CoV-2 spike (S) protein, enabling the virus to enter cells. Here, we show that factor (F) Xa, an SP involved in blood coagulation, is upregulated in COVID-19 patients. In contrast to other SPs, FXa exerts antiviral activity. Mechanistically, FXa cleaves S protein, preventing its binding to ACE2, and thus blocking viral entry and infection. However, FXa is less effective against variants carrying the D614G mutation common in all pandemic variants. The anticoagulant rivaroxaban, a direct FXa inhibitor, inhibits FXa-mediated S protein cleavage and facilitates viral entry, whereas the indirect FXa inhibitor fondaparinux does not. In the lethal SARS-CoV-2 K18-hACE2 model, FXa prolongs survival yet its combination with rivaroxaban but not fondaparinux abrogates that protection. These results identify both a previously unknown function for FXa and an associated antiviral host defense mechanism against SARS-CoV-2 and suggest caution in considering direct FXa inhibitors for preventing or treating thrombotic complications in COVID-19 patients

    SARS-CoV-2 productively infects primary human immune system cells in vitro and in COVID-19 patients

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    The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with a hyperinflammatory state and lymphocytopenia, a hallmark that appears as both signature and prognosis of disease severity outcome. Although cytokine storm and a sustained inflammatory state are commonly associated with immune cell depletion, it is still unclear whether direct SARS-CoV-2 infection of immune cells could also play a role in this scenario by harboring viral replication. We found that monocytes, as well as both B and T lymphocytes, were susceptible to SARS-CoV-2 infection in vitro, accumulating double-stranded RNA consistent with viral RNA replication and ultimately leading to expressive T cell apoptosis. In addition, flow cytometry and immunofluorescence analysis revealed that SARS-CoV-2 was frequently detected in monocytes and B lymphocytes from coronavirus disease 2019 (COVID-19) patients. The rates of SARS-CoV-2-infected monocytes in peripheral blood mononuclear cells from COVID-19 patients increased over time from symptom onset, with SARS-CoV-2-positive monocytes, B cells, and CD4+ T lymphocytes also detected in postmortem lung tissue. These results indicated that SARS-CoV-2 infection of blood-circulating leukocytes in COVID-19 patients might have important implications for disease pathogenesis and progression, immune dysfunction, and virus spread within the host

    The Bright Side to Cuing Consumerism: Consumer Cues Make Individuals With Low Childhood Socioeconomic Status More Prosocial

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    Counter to extant research that finds consumer cues make people more proself, we present four experiments that demonstrate that consumer cues can actually increase prosociality--at least amongst people who grew up with significant economic constraints (i.e., people with low childhood socioeconomic status)

    Sensitivity of predicted bioaerosol exposure from open windrow composting facilities to ADMS dispersion model parameters

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    Bioaerosols are released in elevated quantities from composting facilities and are associated with negative health effects, although dose-response relationships are not well understood, and require improved exposure classification. Dispersion modelling has great potential to improve exposure classification, but has not yet been extensively used or validated in this context. We present a sensitivity analysis of the ADMS dispersion model specific to input parameter ranges relevant to bioaerosol emissions from open windrow composting. This analysis provides an aid for model calibration by prioritising parameter adjustment and targeting independent parameter estimation. Results showed that predicted exposure was most sensitive to the wet and dry deposition modules and the majority of parameters relating to emission source characteristics, including pollutant emission velocity, source geometry and source height. This research improves understanding of the accuracy of model input data required to provide more reliable exposure predictions

    Proposal for a low cost close air support aircraft for the year 2000: The Raptor

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    The Raptor is a proposed low cost Close Air Support (CAS) aircraft for the U.S. Military. The Raptor incorporates a 'cranked arrow' wing planform, and uses canards instead of a traditional horizontal tail. The Raptor is designed to be capable of responsive delivery of effective ordnance in close proximity to friendly ground forces during the day, night, and 'under the weather' conditions. Details are presented of the Raptor's mission, configuration, performance, stability and control, ground support, manufacturing, and overall cost to permit engineering evaluation of the proposed design. A description of the design process and analysis methods used is also provided
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