8,358 research outputs found

    Assault on the Liberty

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    Assault on the Liberty

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    Comparison of Methods for Detecting Voles under Apple Trees

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    We conducted a study in 2 heavily infested orchards in the mid-Hudson Valley of New York to evaluate methods for detecting the presence of meadow voles (MV, Microtus pennsylvanicus) and pine voles (PV, M. pinetorum) under apple trees. We quantified several possible signs indicating the presence of voles in each of the 4 quadrants under the canopy of each tree, and then set and monitored traps until capture success in the orchard declined to zero. There was no evidence that the 4 quadrants differed with respect to any of the variables examined. The apple slice index (ASI) was the best indicator for both species. Detection improved significantly (P \u3c 0.05) when the ASI was used in conjunction with the number of runways (MV) or tunnels (PV) under the tree, although neither of the latter 2 signs was by itself a reliable indicator. The ASI and search for runways and tunnels should be conducted in at least 2 quadrants under each tree. The significance of these findings for managing voles in apple orchards is discussed

    High efficiency GaAs-Ge tandem solar cells grown by MOCVD

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    High conversion efficiency and low weight are obviously desirable for solar cells intended for space applications. One promising structure is GaAs on Ge. The advantages of using Ge wafers as substrates include the following: they offer high efficiency by forming a two-junction tandem cell; low weight combined with superior strength allows usage of thin (3 mil) wafers; and they are a good substrate for GaAs, being lattice matched, thermal expansion matched, and available as large-area wafers

    Coronavirus Health Inequities in the United States Highlight Need for Continued Community Development Efforts

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    The coronavirus (SARS-CoV-2) pandemic of 2020 has shown a spotlight on inequity in the USA. Although these inequities have long existed, the coronavirus and its disparate impact on health in different communities have raised the visibility of these deeply ingrained inequities to a level that has created a new awareness across the US population and an opportunity to use this heightened awareness of the existing conditions for change. ‘Community and social development’ efforts in the post-pandemic USA can be informed by a health justice framework, across economic, societal and cultural, environmental and social dimensions. Dimensions which have all been implicated in the coronavirus response and complement other social and community development models. Although health disparities and inequities did not begin with coronavirus and will not end in the post-pandemic USA, social and community development efforts which value health justice and concentrate on social determinants of health can provide needed policies and programmes for a more equitable US health system

    Predicted Colors and Flux Densities of Protostars in the Herschel PACS and SPIRE Filters

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    Upcoming surveys with the Herschel Space Observatory will yield far-IR photometry of large samples of young stellar objects, which will require careful interpretation. We investigate the color and luminosity diagnostics based on Herschel broad-band filters to identify and discern the properties of low-mass protostars. We compute a grid of 2,016 protostars in various physical congurations, present the expected flux densities and flux density ratios for this grid of protostars, and compare Herschel observations of three protostars to the model results. These provide useful constraints on the range of colors and fluxes of protostar in the Herschel filters. We find that Herschel data alone is likely a useful diagnostic of the envelope properties of young starsComment: Part of HOPS KP papers to the Herschel special A&A issu

    Analysis of cell division patterns in the Arabidopsis shoot apical meristem

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    The stereotypic pattern of cell shapes in the Arabidopsis shoot apical meristem (SAM) suggests that strict rules govern the placement of new walls during cell division. When a cell in the SAM divides, a new wall is built that connects existing walls and divides the cytoplasm of the daughter cells. Because features that are determined by the placement of new walls such as cell size, shape, and number of neighbors are highly regular, rules must exist for maintaining such order. Here we present a quantitative model of these rules that incorporates different observed features of cell division. Each feature is incorporated into a “potential function” that contributes a single term to a total analog of potential energy. New cell walls are predicted to occur at locations where the potential function is minimized. Quantitative terms that represent the well-known historical rules of plant cell division, such as those given by Hofmeister, Errera, and Sachs are developed and evaluated against observed cell divisions in the epidermal layer (L1) of Arabidopsis thaliana SAM. The method is general enough to allow additional terms for nongeometric properties such as internal concentration gradients and mechanical tensile forces

    On the nature of the deeply embedded protostar OMC-2 FIR 4

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    We use mid-infrared to submillimeter data from the Spitzer, Herschel, and APEX telescopes to study the bright sub-mm source OMC-2 FIR 4. We find a point source at 8, 24, and 70 μ\mum, and a compact, but extended source at 160, 350, and 870 μ\mum. The peak of the emission from 8 to 70 μ\mum, attributed to the protostar associated with FIR 4, is displaced relative to the peak of the extended emission; the latter represents the large molecular core the protostar is embedded within. We determine that the protostar has a bolometric luminosity of 37 Lsun, although including more extended emission surrounding the point source raises this value to 86 Lsun. Radiative transfer models of the protostellar system fit the observed SED well and yield a total luminosity of most likely less than 100 Lsun. Our models suggest that the bolometric luminosity of the protostar could be just 12-14 Lsun, while the luminosity of the colder (~ 20 K) extended core could be around 100 Lsun, with a mass of about 27 Msun. Our derived luminosities for the protostar OMC-2 FIR 4 are in direct contradiction with previous claims of a total luminosity of 1000 Lsun (Crimier et al 2009). Furthermore, we find evidence from far-infrared molecular spectra (Kama et al. 2013, Manoj et al. 2013) and 3.6 cm emission (Reipurth et al 1999) that FIR 4 drives an outflow. The final stellar mass the protostar will ultimately achieve is uncertain due to its association with the large reservoir of mass found in the cold core.Comment: Accpeted by ApJ, 17 pages, 11 figure
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