14 research outputs found

    Comments on "Limits on Dark Matter Using Ancient Mica"

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    To appear in Phys. Rev. Lett. together with the author's Reply.Comment: Compressed PostScript (filename.ps.Z), 3 pages, no figure

    CAST constraints on the axion-electron coupling

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    In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axiorecombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling gae and axion-photon interaction strength ga using the CAST phase-I data (vacuum phase). For ma <~ 10 meV/c2 we find ga gae < 8.1 × 10−23 GeV−1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission

    Breeding biology and conservation of the Marsh Seedeater Sporophila palustris

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    El Capuchino Pecho Blanco Sporophila palustris es uno de los capuchinos menos conocidos y uno de los más amenazados. Sus poblaciones reproductivas son locales, fragmentadas y ocurren en el nordeste de Argentina, sudeste de Brasil y en Uruguay. Presentamos datos reproductivos describiendo nidos y huevos, comportamiento (incluyendo cortejo, nidificación, incubación y cuidado parental), sitios de anidación y datos sobre alimentación. El Capuchino Pecho Blanco nidifica en pastizales altos y húmedos en buen estado de conservación. Estos hábitats en general se han convertido en áreas ganaderas. Las principales amenazas son sobrepastoreo, uso generalizado del fuego, drenaje de humedales, reemplazo total del hábitat por pasturas y forestaciones y captura ilegal. La mayoría de los sitios se localizan en AICAs, pero sólo uno en Brasil y otro en Argentina se encuentran protegidos. Finalmente, proponemos una serie de medidas que contribuyen a la preservación del Capuchino Pecho Blanco y de otras aves amenazadas que conviven con este.The Marsh Seedeater Sporophila palustris is one of the most endangered and least known of the capuchino seedeaters. Breeding populations are patchy, occurring in north-east Argentina,southern Brazil, and Uruguay. We present data on the breeding biology of the species, and describe nests and eggs, behaviour (including courtship, nesting, incubation and parental care), breeding sites and food items. Marsh Seedeaters breed in well-preserved grasslands with wet soils and tall vegetation. In general, these habitats are used for extensive livestock ranching. Main threats are overgrazing, widespread use of fire, conversion of grasslands to pastures of exotic grasses and rice fields, afforestation, and illegal trapping. Most breeding sites are located in Important Bird Areas, but only one in Brazil and one in Argentina are protected. We propose a series of actions to promote the conservation of Marsh Seedeaters and other endangered birds that coexist in grassland habitats.Fil: Vizentin Bugoni, Jefferson. Universidade Estadual de Campinas; Brasil;Fil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentina;Fil: Di Giacomo, Alejandro G.. Asociación Ornitológica del Plata. Aves Argentinas. Departamento de Conservación; Argentina;Fil: Di Giacomo, Adrian Santiago. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología y Comportamiento Animal; Argentina;Fil: Jacobs, Fernando. Universidade Federal de Pelotas. Instituto de Biologia. Departamento de Zoologia e Genética; Brasil;Fil: Afonso Coimbra, Marco A.. Universidade Federal de Pelotas. Instituto de Biologia. Núcleo de Reabilitação da Fauna Silvestre e Centro de Triagem de Animais Silvestres; Brasil;Fil: Dias, Rafael A.. Universidade Católica de Pelotas. Laboratório de Biologia e Ecologia de Cordados. Setor de Ornitologia; Brasil

    Coherent elastic neutrino-nucleus scattering at the European Spallation Source

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    The European Spallation Source (ESS), presently well on its way to completion, will soon provide the most intense neutron beams for multi-disciplinary science. Fortuitously, it will also generate the largest pulsed neutrino flux suitable for the detection of Coherent Elastic Neutrino-Nucleus Scattering (CE nu NS), a process recently measured for the first time at ORNL's Spallation Neutron Source. We describe innovative detector technologies maximally able to profit from the order-of-magnitude increase in neutrino flux provided by the ESS, along with their sensitivity to a rich particle physics phenomenology accessible through high-statistics, precision CE nu NS measurements

    A theoretical framework for understanding the ecology and conservation of bamboo-specialist birds

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    Worldwide, populations of a diverse array of bamboo-specialist birds must respond to the life cycles of typical woody bamboos, which include a long vegetative phase, a short period in sexual reproduction (seeding), and a short period dead. While some bamboo species flower continuously in time, but scattered in space, over different parts of their distribution, others exhibit a single, synchronized mass-seeding event, followed by death over hundreds of square kilometers. Thus, bamboo-specialist birds experience extreme variability in their habitat and food sources, and may pass from a period of overabundant habitat and food resources to a period of extreme resource scarcity. At a community level, bamboo species are out of phase with each other. Masting events of several bamboo species may coincide one cycle, but not the next. The resulting long-term dynamics of bamboo cycles at a community scale will result in a temporal and geographic mosaic of resource availability over very long periods of time, where the initial conditions that any bird experienced may occur only sporadically over centuries and very large regions. We aim to propose a theoretical framework for understanding the population ecology of bamboo-specialist birds and discuss implications for their conservation. Three main diet and life-history strategies of bamboo-specialist birds can be identified based on their natural history. First, insectivorous bamboo specialists that inhabit woody bamboos may be relatively sedentary during the long vegetative growth phase, but they must experience population declines, switch to alternative habitat, or travel widely during bamboo die-off events. They benefit from long-term habitat stability but must face short-term reductions in habitat that do not affect all generations of birds. Second, bamboo seed specialists must rely on an ephemeral source of food available only after large intervals of time at most locations. Since bamboo cycles are typically much longer than the lives of individual birds, there is no chance for seed-specialist birds to learn when and where bamboo seeds will be available in the future. Thus, although bamboo seed availability is ecologically predictable (i. e., seeds are always available after the same length of time at a given place), seed availability is unpredictable to individual birds. During their lifetime, most individual bamboo seed-specialists must face a lack of their preferred food supply, at which time they must wander to survive. And third, mixed strategists usually feed on bamboo shoots, leaves, and insects, but consume bamboo seeds when available. Their life history combines elements of both previous categories: they can benefit from long-term habitat stability like insectivores, and take advantage of masting events like seed specialists. Niche width (degree of specialization) in conjugation with the long-term dynamics of bamboo cycles should determine the degree of nomadism and amplitude of bamboo-specialist population cycles. Nomadism appears to be distributed along a continuum from the temporarily nomad insectivores and mixed strategists to the local and regional nomadic seed specialists. A protected area cannot shelter healthy populations of the most specialized bamboo-seed specialists because they track temporally and spatially unpredictable resources over large temporal and spatial scales. Overall, to effectively protect this ecological system, it is crucial to conserve a network of natural areas capable of providing bamboo in different phases and at different times and places, as well as subsidiary food resources that will allow birds to move away from bamboo patches as they become unsuitable to new, suitable patches. © 2012 Dt. Ornithologen-Gesellschaft e.V.Fil: Areta, Juan Ignacio. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina. Grupo FALCO; ArgentinaFil: Cockle, Kristina Louise. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina. Fundación de Historia Natural Félix de Azara; Argentina. Universidad Maimónides; Argentina. University of British Columbia; Canad

    Mineral detection of neutrinos and dark matter. A whitepaper

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    Minerals are solid state nuclear track detectors — nuclear recoils in a mineral leave latent damage to the crystal structure. Depending on the mineral and its temperature, the damage features are retained in the material from minutes (in low-melting point materials such as salts at a few hundred ) to timescales much larger than the 4.5 Gyr-age of the Solar System (in refractory materials at room temperature). The damage features from the fission fragments left by spontaneous fission of 238U and other heavy unstable isotopes have long been used for fission track dating of geological samples. Laboratory studies have demonstrated the readout of defects caused by nuclear recoils with energies as small as keV. This whitepaper discusses a wide range of possible applications of minerals as detectors for keV nuclear recoils: Using natural minerals, one could use the damage features accumulated over Gyr to measure astrophysical neutrino fluxes (from the Sun, supernovae, or cosmic rays interacting with the atmosphere) as well as search for Dark Matter. Using signals accumulated over months to few-years timescales in laboratory-manufactured minerals, one could measure reactor neutrinos or use them as Dark Matter detectors, potentially with directional sensitivity. Research groups in Europe, Asia, and America have started developing microscopy techniques to read out the damage features in crystals left by keV nuclear recoils. We report on the status and plans of these programs. The research program towards the realization of such detectors is highly interdisciplinary, combining geoscience, material science, applied and fundamental physics with techniques from quantum information and Artificial Intelligence
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