708 research outputs found

    Viral pathogens and acute lung injury: investigations inspired by the SARS epidemic and the 2009 H1N1 influenza pandemic.

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    Acute viral pneumonia is an important cause of acute lung injury (ALI), although not enough is known about the exact incidence of viral infection in ALI. Polymerase chain reaction-based assays, direct fluorescent antigen (DFA) assays, and viral cultures can detect viruses in samples from the human respiratory tract, but the presence of the virus does not prove it to be a pathogen, nor does it give information regarding the interaction of viruses with the host immune response and bacterial flora of the respiratory tract. The severe acute respiratory syndrome (SARS) epidemic and the 2009 H1N1 influenza pandemic provided a better understanding of how viral pathogens mediate lung injury. Although the viruses initially infect the respiratory epithelium, the relative role of epithelial damage and endothelial dysfunction has not been well defined. The inflammatory host immune response to H1N1 infection is a major contributor to lung injury. The SARS coronavirus causes lung injury and inflammation in part through actions on the nonclassical renin angiotensin pathway. The lessons learned from the pandemic outbreaks of SARS coronavirus and H1N1 capture key principles of virally mediated ALI. There are pathogen-specific pathways underlying virally mediated ALI that converge onto a common end pathway resulting in diffuse alveolar damage. In terms of therapy, lung protective ventilation is the cornerstone of supportive care. There is little evidence that corticosteroids are beneficial, and they might be harmful. Future therapeutic strategies may be targeted to specific pathogens, the pathogenetic pathways in the host immune response, or enhancing repair and regeneration of tissue damage

    Teacher Response to Student Misbehavior: Assessing Potential Biases in the Classroom

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    Honors (Bachelor's)Biopsychology, Cognition, and Neuroscience (BCN)University of Michiganhttps://deepblue.lib.umich.edu/bitstream/2027.42/147364/1/mhendr.pd

    Electronic and Optical Properties of Vacancy Defects in Transition Metal Dichalcogenides

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    A detailed first-principle study has been performed to evaluate the electronic and optical properties of single-layer (SL) transition metal dichalcogenides (TMDCs) (MX2{}_2; M= transition metal such as Mo, W and X= S, Se, Te), in the presence of vacancy defects (VDs). Defects usually play an important role in tailoring electronic, optical, and magnetic properties of semiconductors. We consider three types of VDs in SL TMDCs i) XX-vacancy, X2X_{2}-vacancy, and iii) MM-vacancy. We show that VDs lead to localized defect states (LDS) in the band structure, which in turn give rise to sharp transitions in in-plane and out-of-plane optical susceptibilities, χ\chi_{\parallel} and χ\chi_{\perp}. The effects of spin orbit coupling (SOC) are also considered. We find that SOC splitting in LDS is directly related to the atomic number of the transition metal atoms. Apart from electronic and optical properties we also find magnetic signatures (local magnetic moment of μB\sim\mu_{B}) in MoSe2_{2} in the presence of Mo vacancy, which breaks the time reversal symmetry and therefore lifts the Kramers degeneracy. We show that a simple qualitative tight binding model (TBM), involving only the hopping between atoms surrounding the vacancy with an on-site SOC term, is sufficient to capture the essential features of LDS. In addition, the existence of the LDS can be understood from the solution of the 2D Dirac Hamiltonian by employing infinite mass boundary conditions. In order to provide a clear description of the optical absorption spectra, we use group theory to derive the optical selection rules between LDS for both χ\chi_{\parallel} and χ\chi_{\perp}.Comment: 14 pages, 11 figure

    Digital Transformation as a Coping Strategy To Deal With The Fallout From The Pandemic In The Caribbean

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    Caribbean economies have been disrupted by the pandemic and the fallout from the war in Ukraine. Therefore, in the short to medium-term, there is need for policies to deal with post-pandemic recovery, including strengthened health and safety protocols, social protection measures and managed economic reopening to stimulate growth and employment

    The Ideological Divide: Conflict and the Supreme Court\u27s Certiorari Decision

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    This Article bridges a gap in existing literature by evaluating, from an empirical perspective, the impact of conflict among the lower courts on the Supreme Court’s decision to grant or deny a petition for a writ of certiorari. Specifically, this Article looks at the political ideology of the lower courts involved in a split of authority on federal law and compares those positions to the political ideology of the Supreme Court itself. This Article concludes that the ideological content of lower court opinions in a conflict case impacts the Supreme Court’s certiorari decisions in a statistically significant way, and thus sheds new light on the role lower court conflict plays in whether the Supreme Court’s exercise of its discretion to grant cert

    A Cross-National Examination of Expected Correlation of Computer Ethical Perceptions and User Computer Attitudes

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    This study examined computer ethical perceptions and computer use attitudes among three differing groups consisting of nationalities from the United States, Singapore and Hong Kong. The purpose of the study was to determine if computer attitudes have a moderating effect on the perceptions of computer ethical use across multiple cultural backgrounds. Evidence supporting this claim would add additional insight into previously discovered differences. This study found limited support for the suggested hypotheses, but confirmed fundamental cultural differences. Future research should examine other variables to determine if significant effects can be determined from unexamined variable

    Review of selected areas of research on the Caribbean subregion in the 2000s: identifying the main gaps

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    Includes bibliographyThis study has been prepared to assist the French Development Agency (AFD), as part of the implementation of its Framework for Action Regional Caribbean, to identify the main development issues of the Caribbean region and areas of future research. The study focuses on the state of the research in the Caribbean region and proposes areas for future collaboration between the Economic Commission for Latin America and the Caribbean (ECLAC) and the AFD. The areas of enquiry cover economic, social and cultural, environmental and international relations, with an emphasis on public policy. The study also presents the key institutions driving the research and the main outcomes of the publications. It also identifies, subject by subject, the main research gaps which emerge despite the considerable body of research done in the region. Caribbean countries have many similarities such as their relatively small size and high vulnerability to external shocks and environmental disasters, however, beneath these similarities can be found different approaches to growth and development. In terms of coverage, this study focuses principally on the Caribbean Community (CARICOM) member States as well as the CARICOM countries plus the Dominican Republic (CARIFORUM), the associate CARICOM member States, the Caribbean observer members and countries of the French Caribbean territories

    Phage-Like Streptococcus pyogenes Chromosomal Islands (SpyCI) and Mutator Phenotypes: Control by Growth State and Rescue by a SpyCI-Encoded Promoter

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    We recently showed that a prophage-like Streptococcus pyogenes chromosomal island (SpyCI) controls DNA mismatch repair and other repair functions in M1 genome strain SF370 by dynamic excision and reintegration into the 5′ end of mutL in response to growth, causing the cell to alternate between a wild type and mutator phenotype. Nine of the 16 completed S. pyogenes genomes contain related SpyCI integrated into the identical attachment site in mutL, and in this study we examined a number of these strains to determine whether they also had a mutator phenotype as in SF370. With the exception of M5 genome strain Manfredo, all demonstrated a mutator phenotype as compared to SpyCI-free strain NZ131. The integrase gene (int) in the SpyCIM5 contains a deletion that rendered it inactive, and this deletion predicts that Manfredo would have a pronounced mutator phenotype. Remarkably, this was found not to be the case, but rather a cryptic promoter within the int ORF was identified that ensured constitutive expression of mutL and the downstream genes encoded on the same mRNA, providing a striking example of rescue of gene function following decay of a mobile genetic element. The frequent occurrence of SpyCI in the group A streptococci may facilitate bacterial survival by conferring an inducible mutator phenotype that promotes adaptation in the face of environmental challenges or host immunity
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