1,216 research outputs found

    Before the Pandemic Ends: Making Sure This Never Happens Again

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    Introduction On 30 January 2020, the World Health Organization (WHO) declared a Global Health Emergency of international concern attendant to the emergence and spread of SARS-CoV-2, nearly two months after the first reported emergence of human cases in Wuhan, China. In the subsequent two months, global, national and local health personnel and infrastructures have been overwhelmed, leading to suffering and death for infected people, and the threat of socio-economic instability and potential collapse for humanity as a whole. This shows that our current and traditional mode of coping, anchored in responses after the fact, is not capable of dealing with the crisis of emerging infectious disease. Given all of our technological expertise, why is there an emerging disease crisis, and why are we losing the battle to contain and diminish emerging diseases? Part of the reason is that the prevailing paradigm explaining the biology of pathogen-host associations (coevolution, evolutionary arms races) has assumed that pathogens must evolve new capacities - special mutations – in order to colonize new hosts and produce emergent disease (e.g. Parrish and Kawaoka, 2005). In this erroneous but broadly prevalent view, the evolution of new capacities creates new opportunities for pathogens. Further, given that mutations are both rare and undirected, the highly specialized nature of pathogen-host relationships should produce an evolutionary firewall limiting dissemination; by those definitions, emergences should be rare (for a historical review see Brooks et al., 2019). Pathogens, however, have become far better at finding us than our traditional understanding predicts. We face considerable risk space for pathogens and disease that directly threaten us, our crops and livestock – through expanding interfaces bringing pathogens and hosts into increasing proximity, exacerbated by environmental disruption and urban density, fueled by globalized trade and travel. We need a new paradigm that explains what we are seeing. Additional section headers: The Stockholm Paradigm The DAMA Protocol A Sense of Urgency and Long-Term Commitment Reference

    Spitzer Space Telescope observations of the Carina Nebula: The steady march of feedback-driven star formation

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    We report the first results of imaging the Carina Nebula with Spitzer/IRAC, providing a catalog of point sources and YSOs based on SED fits. We discuss several aspects of the extended emission, including dust pillars that result when a clumpy molecular cloud is shredded by massive star feedback. There are few "extended green objects" (EGOs) normally taken as signposts of outflow activity, and none of the HH jets detected optically are seen as EGOs. A population of "extended red objects" tends to be found around OB stars, some with clear bow-shocks. These are dusty shocks where stellar winds collide with flows off nearby clouds. Finally, the relative distributions of O stars and subclusters of YSOs as compared to dust pillars shows that while some YSOs are located within pillars, many more stars and YSOs reside just outside pillar heads. We suggest that pillars are transient phenomena, part of a continuous outwardly propagating wave of star formation driven by massive star feedback. As pillars are destroyed, they leave newly formed stars in their wake, which are then subsumed into the young OB association. Altogether, the current generation of YSOs shows no strong deviation from a normal IMF. The number of YSOs suggests a roughly constant star-formation rate over the past 3Myr, implying that star formation in pillars constitutes an important mechanism to construct unbound OB associations. Accelerated pillars may give birth to O-type stars that, after several Myr, could appear to have formed in isolation.Comment: 25 pages, 15 figures, MNRAS accepte

    Exercise Training Amount and Intensity Effects on Metabolic Syndrome (From Studies of a Targeted Risk Reduction Intervention through Defined Exercise)

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    Although exercise improves individual risk factors of the metabolic syndrome (MS), there is little research on the effect of exercise on MS as a whole. The objective of this study was to determine how much exercise is recommended to reduce the prevalence of MS. Of 334 subjects randomized, 227 finished and 171 (80 women, 91 men) had complete data for all 5 Adult Treatment Panel III- defined MS risk factors and were included in this analysis. Subjects were randomly assigned to a six-month control or 1 of 3 eight-month exercise training groups: 1) low-amount/moderate-intensity (equivalent to walking ~19 km/week); 2) low-amount/vigorous-intensity (equivalent to jogging ~19 km/week); 3) high-amount/vigorous-intensity (equivalent to jogging ~32 km/week). The low- amount/moderate-intensity exercise prescription improved MS relative to inactive controls (p<0.05). However, the same amount of exercise at a vigorous intensity was not significantly better than inactive controls, suggesting that lower intensity exercise may be more effective in improving MS. The high-amount/vigorous-intensity group improved MS relative to controls (p<0.0001), the low- amount/vigorous-intensity group (p=0.001), and the moderate intensity group (p=0.07), suggesting an exercise dose effect. In conclusion, a modest amount of moderate intensity exercise, in the absence of dietary changes, significantly improved MS and thus supports the recommendation that adults get 30 minutes of moderate intensity exercise every day. A higher amount of vigorous exercise was shown to have greater and more widespread benefits. Finally, there is an indication that moderate intensity may be better than vigorous intensity exercise for improving MS. Originally published American Journal of Cardiology, Vol. 100, No. 12, Dec 200

    Natural HLA Class I Polymorphism Controls the Pathway of Antigen Presentation and Susceptibility to Viral Evasion

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    HLA class I polymorphism creates diversity in epitope specificity and T cell repertoire. We show that HLA polymorphism also controls the choice of Ag presentation pathway. A single amino acid polymorphism that distinguishes HLA-B*4402 (Asp116) from B*4405 (Tyr116) permits B*4405 to constitutively acquire peptides without any detectable incorporation into the transporter associated with Ag presentation (TAP)-associated peptide loading complex even under conditions of extreme peptide starvation. This mode of peptide capture is less susceptible to viral interference than the conventional loading pathway used by HLA-B*4402 that involves assembly of class I molecules within the peptide loading complex. Thus, B*4402 and B*4405 are at opposite extremes of a natural spectrum in HLA class I dependence on the PLC for Ag presentation. These findings unveil a new layer of MHC polymorphism that affects the generic pathway of Ag loading, revealing an unsuspected evolutionary trade-off in selection for optimal HLA class I loading versus effective pathogen evasion
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