92 research outputs found

    Effects of schistosomes on host anti-viral immune response and the acquisition, virulence, and prevention of viral infections: A systematic review.

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    Although a growing number of studies suggest interactions between Schistosoma parasites and viral infections, the effects of schistosome infections on the host response to viruses have not been evaluated comprehensively. In this systematic review, we investigated how schistosomes impact incidence, virulence, and prevention of viral infections in humans and animals. We also evaluated immune effects of schistosomes in those coinfected with viruses. We screened 4,730 studies and included 103. Schistosomes may increase susceptibility to some viruses, including HIV and Kaposi's sarcoma-associated herpesvirus, and virulence of hepatitis B and C viruses. In contrast, schistosome infection may be protective in chronic HIV, Human T-cell Lymphotropic Virus-Type 1, and respiratory viruses, though further research is needed. Schistosome infections were consistently reported to impair immune responses to hepatitis B and possibly measles vaccines. Understanding the interplay between schistosomes and viruses has ramifications for anti-viral vaccination strategies and global control of viral infections

    The Buffer Gas Beam: An Intense, Cold, and Slow Source for Atoms and Molecules

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    Beams of atoms and molecules are stalwart tools for spectroscopy and studies of collisional processes. The supersonic expansion technique can create cold beams of many species of atoms and molecules. However, the resulting beam is typically moving at a speed of 300-600 m/s in the lab frame, and for a large class of species has insufficient flux (i.e. brightness) for important applications. In contrast, buffer gas beams can be a superior method in many cases, producing cold and relatively slow molecules in the lab frame with high brightness and great versatility. There are basic differences between supersonic and buffer gas cooled beams regarding particular technological advantages and constraints. At present, it is clear that not all of the possible variations on the buffer gas method have been studied. In this review, we will present a survey of the current state of the art in buffer gas beams, and explore some of the possible future directions that these new methods might take

    Why Every Economist Should Learn Some Auction Theory

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    The Impact of Brand Quality on Shareholder Wealth

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    This study examines the impact of brand quality on three components of shareholder wealth: stock returns, systematic risk, and idiosyncratic risk. The study finds that brand quality enhances shareholder wealth insofar as unanticipated changes in brand quality are positively associated with stock returns and negatively related to changes in idiosyncratic risk. However, unanticipated changes in brand quality can also erode shareholder wealth because they have a positive association with changes in systematic risk. The study introduces a contingency theory view to the marketing-finance interface by analyzing the moderating role of two factors that are widely followed by investors. The results show an unanticipated increase (decrease) in current-period earnings enhances (depletes) the positive impact of unanticipated changes in brand quality on stock returns and mitigates (enhances) their deleterious effects on changes in systematic risk. Similarly, brand quality is more valuable for firms facing increasing competition (i.e., unanticipated decreases in industry concentration). The results are robust to endogeneity concerns and across alternative models. The authors conclude by discussing the nuanced implications of their findings for shareholder wealth, reporting brand quality to investors, and its use in employee evaluation

    Multimarket Oligopoly.

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    Actions a firm takes in one market may affect its profitability in other markets, beyond any joint economies or diseconomies in production. The reason is that an action in one market, by changing marginal costs in a second market, may change competitors' strategies in that second market. We show how to calculate the strategic consequences in market 2, of a change in conditions in market 1 or of a firm's action in market 1. Qualitatively, the same results hold for both simultaneous markets and sequential markets: whether a more aggressive (i.e., lower price or higher quantity) strategy in the first market provides strategic costs or benefits depends on (a) whether competitors' products are strategic substitutes or strategic complements. The latter distinction is determined by whether more aggressive play by one firm in a market raises or lowers competing firms' marginal profitabilities in that market. We discuss applications to how firms select "portfolios" of businesses in which to compete, to rational retaliation as a barrier to entry, to international trade, and to the learning curve. Both strategic substitutes competition and strategic complements competition are compatible with either quantity competition or price competition. For example, strategic complements competition arises from price competition with linear demand and from quantity competition with constant elasticity demand. The distinction between strategic substitutes and strategic complements is also important in other areas of industrial organization. For example, we show that with strategic complements competition firms will strategically underinvest in fixed costs. This contrasts with earlier studies which, focusing on the total profits of potential entrants rather than the marginal profits of established competitors, invariably emphasized the use of excess capacity
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