1,067 research outputs found

    The reactor antineutrino anomaly and low energy threshold neutrino experiments

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    Short distance reactor antineutrino experiments measure an antineutrino spectrum a few percent lower than expected from theoretical predictions. In this work we study the potential of low energy threshold reactor experiments in the context of a light sterile neutrino signal. We discuss the perspectives of the recently detected coherent elastic neutrino-nucleus scattering in future reactor antineutrino experiments. We find that the expectations to improve the current constraints on the mixing with sterile neutrinos are promising. We also analyse the measurements of antineutrino scattering off electrons from short distance reactor experiments. In this case, the statistics is not competitive with inverse beta decay experiments, although future experiments might play a role when compare it with the Gallium anomaly.Comment: 9 pages, 6 figures, 1 table, matches published versio

    A game of russian roulette for a generalist dinoflagellate parasitoid: Host susceptibility is the key to success

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    © 2016 Alacid, Park, Turon, Petrou and Garcés. Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity. Parvilucifera sinerae is a generalist parasitoid able to infect a wide range of dinoflagellates, including toxic-bloom-forming species. A density-dependent chemical cue has been identified as the trigger for the activation of the infective stage. Together these traits make Parvilucifera-dinoflagellate hosts a good model to investigate the degree of specificity of a generalist parasitoid, and the potential effects that it could have at the community level. Here, we present for the first time, the strategy by which a generalist dinoflagellate parasitoid seeks out its host and determine whether it exhibits host preferences, highlighting key factors in determining infection. Our results demonstrate that in its infective stage, P. sinerae is able to sense potential hosts, but does not actively select among them. Instead, the parasitoids contact the host at random, governed by the encounter probability rate and once encountered, the chance to penetrate inside the host cell and develop the infection strongly depends on the degree of host susceptibility. As such, their strategy for persistence is more of a game of Russian roulette, where the chance of survival is dependent on the susceptibility of the host. Our study identifies P. sinerae as a potential key player in community ecology, where in mixed dinoflagellate communities consisting of hosts that are highly susceptible to infection, parasitoid preferences may mediate coexistence between host species, reducing the dominance of the superior competitor. Alternatively, it may increase competition, leading to species exclusion. If, however, highly susceptible hosts are absent from the community, the parasitoid population could suffer a dilution effect maintaining a lower parasitoid density. Therefore, both host community structure and host susceptibility will determine infectivity in the field

    Optical sorting and detection of sub-micron objects in a motional standing wave

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    An extended interference pattern close to surface may result in both a transmissive or evanescent surface fields for large area manipulation of trapped particles. The affinity of differing particle sizes to a moving standing wave light pattern allows us to hold and deliver them in a bi-directional manner and importantly demonstrate experimentally particle sorting in the sub-micron region. This is performed without the need of fluid flow (static sorting). Theoretical calculations experimentally confirm that certain sizes of colloidal particles thermally hop more easily between neighboring traps. A new generic method is also presented for particle position detection in an extended periodic light pattern and applied to characterization of optical traps and particle behaviorComment: 5 pages, 6 figures, Optical Trapping pape

    Exceptional crocodylomorph biodiversity of “La Cantalera” site (Lower barremian; lower cretaceous) in Teruel, Spain

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    The palaeontological site of La Cantalera in Teruel, Spain (Blesa Formation, Lower Cretaceous) can be characterized as the site with the greatest biodiversity of vertebrates (32 taxa) from the lower Barremian of the Iberian Peninsula. Remains of amphibians, lizards, turtles, crocodiles, pterosaurs, dinosaurs and mammals have been recovered. The most common taxa are crocodylomorphs, and their most abundant remains are small isolated teeth. Six morphotypes have been identified, which may correspond to at least four different sympatric crocodylomorph taxa. This site presents a similar assemblage to other European Lower Cretaceous sites, with morphotypes that may correspond to the families Goniopholididae, Bernissartiidae, Atoposauridae and multiple ziphodont crocodylomorphs. The crocodylomorph assemblage of La Cantalera is characterized by the absence of large individuals and presents a wide variety of dental morphologies adapted to diets ranging from generalist to highly specialized. This rich biodiversity could be due to concentration of vertebrates into restricted flooded areas during dry seasons within a marsh ecosystem. Furthermore, La Cantalera could also be close to a nesting area, which would explain the abundance of small-sized individuals and the presence of fossil crocodiloid eggshells
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