2,748 research outputs found

    The geometry of human nutrition

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    Food, “Culture,” and Sociality in Drosophila

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    International audiencewith naïve " observers " with two fresh, flavored media (without quinine). In the critical test phase, demonstrators and observers were exposed separately to the two flavored media. Social transmission occurred if the oviposition choices of observers mirrored that of demonstrators. Using this methodology, Battesti et al. (2012) first showed that observer flies relied heavily on social information and acquired oviposition preferences from demonstrators , even if they had the opportunity to sample the two equally suitable media during the transmission phase, thus confirming previous observations in this species (Sarin and Dukas, 2009). The authors next investigated the mechanisms of social transmission and showed that social learning did not occur when observers were exposed to social cues only (freshly laid eggs and aggregation phero-mone) on one of the two media. Social transmission, however, always occurred when observers interacted directly with demonstrators, even if the media were unflavored. Although the precise mechanism of social learning remains an open A commentary on Spread of social information and dynamics of social transmission within Drosophila groups by Battesti Communication with and learning from others are key features of social life. We humans rely extensively on the advice of others before making important decisions. Social insects too, such as bees and ants, use social information to learn about foraging opportunities and engage in collective tasks (Dussutour and Simpson, 2009; Seeley et al., 2012). Growing interest into the learning abilities of small-brained animals has revealed that social learning in insects is more diverse and more common than previously thought (Leadbeater and Chittka, 2007), thus offering new opportunities for comparative analyses of the role of cognition in the regulation of social behavior across a rich spectrum of social forms. Recently, the fruit fly Drosophila melanogaster (Figure 1A) has emerged as a key species for studying social learning in simple insect groups (Mery et al., 2009; Sarin and Dukas, 2009). Flies aggregate on food resources, where they feed, reproduce, lay eggs, and glean information from each other. Writing in a recent issue of Current Biology, Battesti et al. (2012) present evidence that Drosophila females not only use social information to select oviposition sub-strates, but also that these socially acquired preferences can propagate and stabilize within groups, a phenomenon resembling cultural transmission of knowledge in vertebrates (Laland, 2008). The authors used a three-step experimental paradigm (Figure 1B). A group of flies was first trained to associate an aversive gustatory cue (quinine) with an artificial flavor (banana or strawberry) characterizing one of two standard ovipo-sition media (agar and sugar). These conditioned " demonstrators " were then caged question, presumably, it can be explained by relatively simple associative learning processes occurring during physical contacts between observer and demonstrator flies through the perception of the olfactory cues (banana or strawberry flavors) carried by the demonstrators. Such mechanism, for instance, underpins social transmission of food preferences in rats (Galef et al., 1985). In a third set of experiments, Battesti et al. (2012) have gone a step further into the understanding of how flies balance their use of social and personal information. By exposing observers to the two flavored media at the different phases of the experimental paradigm they demonstrated that the socially acquired preference vanished if observers were allowed to acquire personal information after the transmission phase. Considering the short lifespan of Drosophila (Lee et al., 2008), rapidly adopting the behavior of the majority may provide naïve flies with cues to choices that are locally adaptive and prevent costly trial and error. However, if information about resources is abundant and not costly t

    Direct and trans-generational effects of male and female gut microbiota in Drosophila melanogaster

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    Funding This study was supported by the National Council for Scientific and Technological Development (CNPq). Acknowledgement We acknowledge Stuart Wigby, Adam Wong and Phil Taylor for discussion and support during the experiment.Peer reviewedPublisher PD

    Long-term effects of allergen sensitization and exposure in adult asthma: a prospective study.

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    BACKGROUND: : We investigated the effects of sensitization and exposure to common domestic allergens on longitudinal changes in lung function and bronchial hyperresponsiveness. METHODS: : Subjects attended 2 visits that were 4 years apart. Skin prick testing was performed and household dust samples were collected for quantification of mite, dog, and cat allergens at baseline. Measurements of lung function, exhaled nitric oxide, and bronchial hyperresponsiveness were completed at both visits. RESULTS: : Dust samples were collected in 165 of the 200 subjects completing both visits. Mean length of follow-up was 47 months. Bronchial hyperresponsiveness, measured at both visits in 86 subjects, deteriorated in those exposed to high mite allergen levels compared with those not exposed [mean (95% CI) doubling dose change PD20 = -0.44 (-1.07 to 0.19) vs 0.82 (0.27 to 1.36)], but improved in those exposed to high dog allergen levels compared with those not exposed [1.10 (0.33 to 1.86) vs 0.10 (-0.39 to 0.58)]. The associations were significant in the multivariate models. Cat allergen exposure was not associated with any changes in lung function, exhaled nitric oxide, or bronchial hyperresponsiveness. CONCLUSIONS: : In a 4-year prospective cohort of persons with asthma, exposure to high levels of dust mite allergens at baseline was associated with a subsequent increase in bronchial hyperresponsiveness

    The Source of Alabama’s Abundance of Arbitration Cases: Alabama’s Bizarre Law of Damages for Mental Anguish

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    This Article gives an overview of arbitration litigation in Alabama, including the evolution of mental anguish jurisprudence in contract cases, especially with regard to the automobile and home industries; a proposal to bring Alabama law in line with controlling authorities through substantive and procedural reforms; and an appendix listing a decade of arbitration cases decided by Alabama appellate courts
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