7,022 research outputs found

    The sexually antagonistic genes of Drosophila melanogaster

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    When selective pressures differ between males and females, the genes experiencing these conflicting evolutionary forces are said to be sexually antagonistic. Although the phenotypic effect of these genes has been documented in both wild and laboratory populations, their identity, number, and location remains unknown. Here, by combining data on sex-specific fitness and genome-wide transcript abundance in a quantitative genetic framework, we identified a group of candidate genes experiencing sexually antagonistic selection in the adult, which correspond to 8% of Drosophila melanogaster genes. As predicted, the X chromosome is enriched for these genes, but surprisingly they represent only a small proportion of the total number of sex-biased transcripts, indicating that the latter is a poor predictor of sexual antagonism. Furthermore, the majority of genes whose expression profiles showed a significant relationship with either male or female adult fitness are also sexually antagonistic. These results provide a first insight into the genetic basis of intralocus sexual conflict and indicate that genetic variation for fitness is dominated and maintained by sexual antagonism, potentially neutralizing any indirect genetic benefits of sexual selection

    Trust and the Decision to Outsource: Affective Responses and Cognitive Processes

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    Many of the various forms of cooperative strategy that firms are pursuing in today's economy entail the placing of important business functions in the hands of a partner. This paper examines the role of trust in the decision by a producer to place the marketing function in the hands of another entity, namely a cooperative. Although others have studied the effect of what may be termed general trust on inter-organizational relationships, few have examined the antecedents of that trust. We propose a model in which affective responses and cognitive processes are precursors to a sense of general trust, which, in turn, influences the outsourcing decision. These affective responses and cognitive processes have both direct and indirect (mediated) effects on the decision to place an important function in the hands of another entity. Perceptions of partner expertise in the business function at hand and the perceived need for the focal firm to maintain control over that function are also considered in the model. The model is tested in a somewhat novel context: the decision of cotton producers to outsource the marketing of their cotton fiber. Using survey data gathered from the actual decision-maker, and structural equations modeling, we find that the inclusion of affective responses and cognitive processes in our model produces a richer explanation of the outsourcing decision. The differences between the effects of affective responses and cognitive processes have potentially important implications for managers engaged in cooperative strategies and for the scholars who study them.Agribusiness,

    Analysis of routine communication in the air traffic control system

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    The present project has three related goals. The first is to describe the organization of routine controller-pilot communication. This includes identifying the basic units of communication and how they are organized into discourse, how controllers and pilots use language to achieve their goals, and what topics they discuss. The second goal is to identify the type and frequency of problems that interrupt routine information transfer and prompt pilots and controllers to focus on the communication itself. The authors analyze the costs of these problems in terms of communication efficiency, and the techniques used to resolve these problems. Third, the authors hope to identify factors associated with communication problems, such as deviations from conventional air traffic control procedures

    A catalog of radio observations of Jupiter 1961-1964

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    Catalog of radio observations of Jupiter 1961 to 196

    The evolution of sex differences in disease

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    It is now becoming widely recognized that there are important sex differences in disease. These include rates of disease incidence, symptoms and age of onset. These differences between the sexes can be seen as a subset of the more general phenomenon of sexual dimorphism of quantitative phenotypes. From a genetic point of view, this is paradoxical, since the vast majority of genetic material is shared between the sexes. How can males and females differ in so many ways and yet have a common genetic code? Traditionally, the modifying action of hormones has been offered as a solution to this paradox, but experiments disentangling the effects of hormones and sex-chromosomes have shown that this cannot be the sole explanation. In this review, I outline current ideas about the evolutionary origins of sex differences in phenotypes, with a particular focus on how sex differences in disease can arise. I also discuss how sex differences in themselves can generate new risk factors for disease, in effect becoming a new environmental factor, as well as briefly reviewing more general evidence for sexually antagonistic selection and genetic variation within humans. Taking an evolutionary view on sex differences in disease provides an opportunity for greater understanding of mechanisms of disease and as such provides a clear motivation for clinicians to explore how therapies may be tailored to the individual in a sex-dependent way

    Road Oil and Powdered Asphalt

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    A Recount by Species of the Trees of Mount Pleasant, Iowa

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    During the winter of 1924-25, a count by species of the trees within the city limits of Mt. Pleasant was made by the students of the Biology Department of Iowa Wesleyan College. A recount of the trees in this area was made by the students during the winters of 1945-46-47. All trees over four inches in diameter at breast height were counted

    Association of Chorioamnionitis with Aberrant Neonatal Gut Colonization and Adverse Clinical Outcomes.

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    ObjectiveChorioamnionitis (inflammation of the placenta and fetal membranes) and abnormal gastrointestinal colonization have been associated with an increased risk of sepsis and death in preterm infants, but whether chorioamnionitis causes abnormal pioneering gastrointestinal colonization in infants is not known. We determined the relationship between chorioamnionitis, altered infant fecal microbiome indicating abnormal gastrointestinal colonization, and adverse outcomes.Study designPreterm infants ≤ 28 weeks at birth were enrolled from 3 level III NICUs in Cincinnati, Ohio and Birmingham, Alabama. Sequencing for 16S microbial gene was performed on stool samples in the first 3 weeks of life. Chorioamnionitis was diagnosed by placental histology. Late onset sepsis and death outcomes were analyzed in relation to fecal microbiota and chorioamnionitis with or without funisitis (inflammation of the umbilical cord).ResultsOf the 106 enrolled infants, 48 infants had no chorioamnionitis, 32 infants had chorioamnionitis but no funisitis (AC), and 26 infants had chorioamnionitis with funisitis (ACF). The fecal samples from ACF infants collected by day of life 7 had higher relative abundance of family Mycoplasmataceae (phylum Tenericutes), genus Prevotella (phylum Bacteroidetes) and genus Sneathia (phylum Fusobacteria). Further, AC and ACF infants had higher incidence of late-onset sepsis/death as a combined outcome. Presence of specific clades in fecal samples, specifically, order Fusobacteria, genus Sneathia or family Mycoplasmataceae, were significantly associated with higher risk of sepsis or death.ConclusionThe results support the hypothesis that specific alterations in the pioneering infant gastrointestinal microbiota induced by chorioamnionitis predispose to neonatal sepsis or death

    B790: Effects of the Symbex System on Yield, Quality, and Tuber Size Distribution of Katahdin Potatoes Maine -- 1979-81

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    This paper reports on three years of research conducted at Aroostook Farm; Presque Isle, Maine, to determine the effectiveness of Symbex System products for improving the yield and quality of Katahdin potatoes. These products included the following: Symbex, a bacterial soil inoculant; Symbooster, a non-inoculated soil additive containing nutrients for microbial development; Symcoat, a bacterial seedpiece treatment; and Symspray, a foliar applied plant food supplement.https://digitalcommons.library.umaine.edu/aes_bulletin/1125/thumbnail.jp

    Probiotics in the intensive care unit: why controversies and confusion abound

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    Probiotics are living microorganisms that, when administered in adequate amounts, confer health benefits on the host. Because probiotics are not marketed as pharmaceuticals, they are commercially available without rigorous scientific documentation of their efficacy for many health-related claims. Results from existing clinical trials are both confusing and controversial. The evidence base is relatively limited, includes studies with varied designs, assesses multiple probiotic preparations across discrepant disease states, and provides conflicting results. Recent advances in the delineation of probiotics' mechanisms of action offer the opportunity to construct a more logical framework within which future trials are designed
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