11,258 research outputs found

    Master\u27s Project - Wildlife Habitat Linkages Surrounding the Lake George and Southern Lake Champlain Region

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    Conservation priorities – when developed systematically and objectively – can maximize land protection efforts in heterogeneous landscapes susceptible to parcelization and development. One such region surrounds Lake George and Southern Lake Champlain, nested between the Green and Adirondack Mountains. This mosaic of conserved and private parcels sits upon an array of forest, agriculture, wetland, and development valuable to both humans and resident wildlife species. This landscape’s inherent connectedness provides many benefits to wildlife, including species richness, enhanced persistence, and increased genetic interchange. However, it is difficult to make definitive statements about potential wildlife movement through such complex matrices. Therefore, wildlife modeling approaches have evolved to paint a clearer picture of landscape connectivity. Sam Talbot, ecological planning graduate student at the University of Vermont, worked with the Lake Champlain Land Trust and Lake George Land Conservancy to incorporate landscape connectivity and wildlife corridors into their strategic conservation planning efforts. This project, including a least-cost corridor analysis of the region to highlight large swaths of contiguous habitat, provides the information critical to such conservation efforts. Using the ArcGIS program CorridorDesigner to conduct the analysis, with custom model parameters, identifies three discrete latitudinal corridors between large established wildland blocks. These outputs were then evaluated and compared based on several landscape factors. Ultimately, this study will inform conservation and management decisions, as well as enhance dialogue among local conservation organizations

    Chemical accuracy from quantum Monte Carlo for the Benzene Dimer

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    We report an accurate study of interactions between Benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory (DFT) using different van der Waals (vdW) functionals. In our QMC calculations, we use accurate correlated trial wave functions including three-body Jastrow factors, and backflow transformations. We consider two benzene molecules in the parallel displaced (PD) geometry, and find that by highly optimizing the wave function and introducing more dynamical correlation into the wave function, we compute the weak chemical binding energy between aromatic rings accurately. We find optimal VMC and DMC binding energies of -2.3(4) and -2.7(3) kcal/mol, respectively. The best estimate of the CCSD(T)/CBS limit is -2.65(2) kcal/mol [E. Miliordos et al, J. Phys. Chem. A 118, 7568 (2014)]. Our results indicate that QMC methods give chemical accuracy for weakly bound van der Waals molecular interactions, comparable to results from the best quantum chemistry methods.Comment: Accepted for publication in the Journal of Chemical Physics, Vol. 143, Issue 11, 201

    Low-pressure phase diagram of crystalline benzene from quantum Monte Carlo

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    We study the low-pressure (0 to 10 GPa) phase diagram of crystalline benzene using quantum Monte Carlo (QMC) and density functional theory (DFT) methods. We consider the PbcaPbca, P43212P4_32_12, and P21/cP2_1/c structures as the best candidates for phase I and phase II. We perform diffusion quantum Monte Carlo (DMC) calculations to obtain accurate static phase diagrams as benchmarks for modern van der Waals density functionals. We use density functional perturbation theory to compute phonon contribution in the free-energy calculations. Our DFT enthalpy-pressure phase diagram indicates that the PbcaPbca and P21/cP2_1/c structures are the most stable phases within the studied pressure range. The DMC Gibbs free-energy calculations predict that the room temperature PbcaPbca to P21/cP2_1/c phase transition occurs at 2.1(1) GPa. This prediction is consistent with available experimental results at room temperature. Our DMC calculations show an estimate of 50.6±\pm0.5 kJ/mol for crystalline benzene lattice energy

    Agricultural Information Needs and Food Access in the Stann Creek District of Belize

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    The purpose of this study was to describe agricultural information sources available to farmers and to describe food access and availability for the people of Dangriga, Stann Creek, Belize. This study used descriptive survey research methods with convenience sampling of the general public (n=22) and of farmers (n = 38) in the summer of 2017. Farmers use a variety of agricultural information sources with the extension service cited most often, followed by friends and fellow farmers. Weather, lack of information, pests, and inadequate access to capital were of primary concern for farmers. Face-to-face meetings were used most often by extension officers for disseminating agricultural information. Smallholder farmers and the general public have very similar levels of food access and availability. No significant difference was foundbetween the smallholder farmers and the general public on food insecurity with both groups reporting mild to severe food insecurity. Recommendations focused on practical operational strategies for the local Department of Agriculture, as well as the Belize Ministry of Agriculture to eradicate hungerand increase overall food access and availability throughout Belize

    Drop spreading and drifting on a spatially heterogeneous film: capturing variability with asymptotics and emulation

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    A liquid drop spreading over a thin heterogeneous precursor film (such as an inhaled droplet on the mucus-lined wall of a lung airway) will experience perturbations in shape and location as its advancing contact line encounters regions of low or high film viscosity. Prior work on spatially one-dimensional spreading over a precursor film having a random viscosity field [Xu & Jensen 2016, Proc. Roy. Soc. A 472, 20160270] has demonstrated how viscosity fluctuations are swept into a narrow region behind the contact line, where they can impact drop dynamics. Here we investigate two-dimensional drops, seeking to understand the relationship between the statistical properties of the precursor film and those of the spreading drop. Assuming the precursor film is much thinner than the drop and viscosity fluctuations are weak, we use asymptotic methods to derive explicit predictions for the mean and variance of drop area and the drop's lateral drift. For larger film variability, we use Gaussian process emulation to estimate the variance of outcomes from a restricted set of simulations. Stochastic drift of the droplet is predicted to be greatest when the initial drop diameter is comparable to the correlation length of viscosity fluctuations.Comment: 23 pages, 5 figure

    Estimation of geopotential from satellite-to-satellite range rate data: Numerical results

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    A technique for high-resolution geopotential field estimation by recovering the harmonic coefficients from satellite-to-satellite range rate data is presented and tested against both a controlled analytical simulation of a one-day satellite mission (maximum degree and order 8) and then against a Cowell method simulation of a 32-day mission (maximum degree and order 180). Innovations include: (1) a new frequency-domain observation equation based on kinetic energy perturbations which avoids much of the complication of the usual Keplerian element perturbation approaches; (2) a new method for computing the normalized inclination functions which unlike previous methods is both efficient and numerically stable even for large harmonic degrees and orders; (3) the application of a mass storage FFT to the entire mission range rate history; (4) the exploitation of newly discovered symmetries in the block diagonal observation matrix which reduce each block to the product of (a) a real diagonal matrix factor, (b) a real trapezoidal factor with half the number of rows as before, and (c) a complex diagonal factor; (5) a block-by-block least-squares solution of the observation equation by means of a custom-designed Givens orthogonal rotation method which is both numerically stable and tailored to the trapezoidal matrix structure for fast execution

    Letter from Sam E. Smith to Pauline Smith; November 2, 1935

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    From the Ellard-Murphree-Pilgreen-Smith Family Papers Collectionhttps://athenacommons.muw.edu/smithpapers/1036/thumbnail.jp

    A History and Explanation of Montana Disciplinary Practices

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    A History and Explanation of Montana Disciplinary Practice
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