157 research outputs found

    Elk summer-autumn habitat selection in the Clearwater Basin of north-central Idaho

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    Since the 1960\u27s, Rocky Mountain elk (Cervus elaphus nelsoni) populations have declined steadily in the Clearwater Basin in north-central Idaho. The Clearwater Basin Collaborative (CBC) was formed with the goal of restoring healthy elk populations to the Clearwater Basin. They initiated this study by collaring 53 cow elk from four distinct areas. I analyzed elk detection and GIS-based habitat data from June 15-September 15 2014 to address one of the CBC\u27s objectives: identifying elk habitat use responses on summer-autumn range. Ground-truth surveys are necessary to verify satellite-derived data are analogous to actual vegetation components. I used a proportion analysis to compare satellite derived cover type and forest cover to the true on-the-ground cover type and forest cover classification. All habitats had over 85% accuracy in the cover type validation analysis and 84% in the percent forest cover validation analysis. To assess the summer-autumn habitat selection of elk I used a new modeling approach with a use-availability design, the Synoptic model, to assess the importance of topography (valley and midslope), forage emergence and senescence (NDVI and NDVI*forest), the type of habitat (shrub, forested, or herbaceous), and forest cover (high and low) to elk habitat selection. The relative variable importance of habitat variables in descending order was: forest, valley, shrub, lowcover, NDVI and NDVI*forest, midslope, and highcover. I used a MANOVA to test for overall differences in mean habitat selection coefficients among populations. MANOVA results showed there was no significant difference in habitat selection among populations. Then, I examined how distribution patterns related to habitat variables by calculating a habitat suitability index (HSI) for each of the four populations. Overall, elk showed a positive relationship with shrub and forest, and a negative relationship with valleys and high cover in the four populations. The results of this study indicated that elk select for a juxtaposition of both forage and cover, and used high to moderate elevations during the summer. The CBC has attributed declines in the Clearwater Basin elk populations to the loss of early-seral shrub habitat and subsequent limiting effects of summer-autumn nutrition. Based on this analysis, elk populations would be enhanced by converting areas of contiguous forest cover to a diversity of seral communities, particularly early-seral shrubs with adjacent forest stands. These results will help us recognize resources important for elk conservation or habitat improvement, and inform ongoing research in identifying elk nutritional status and population responses on summer-autumn range --Leaf iv

    Dictionary Learning-based Inpainting on Triangular Meshes

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    The problem of inpainting consists of filling missing or damaged regions in images and videos in such a way that the filling pattern does not produce artifacts that deviate from the original data. In addition to restoring the missing data, the inpainting technique can also be used to remove undesired objects. In this work, we address the problem of inpainting on surfaces through a new method based on dictionary learning and sparse coding. Our method learns the dictionary through the subdivision of the mesh into patches and rebuilds the mesh via a method of reconstruction inspired by the Non-local Means method on the computed sparse codes. One of the advantages of our method is that it is capable of filling the missing regions and simultaneously removes noise and enhances important features of the mesh. Moreover, the inpainting result is globally coherent as the representation based on the dictionaries captures all the geometric information in the transformed domain. We present two variations of the method: a direct one, in which the model is reconstructed and restored directly from the representation in the transformed domain and a second one, adaptive, in which the missing regions are recreated iteratively through the successive propagation of the sparse code computed in the hole boundaries, which guides the local reconstructions. The second method produces better results for large regions because the sparse codes of the patches are adapted according to the sparse codes of the boundary patches. Finally, we present and analyze experimental results that demonstrate the performance of our method compared to the literature

    Entornos virtuales de aprendizaje y expresión escrita: un estudio preliminar

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    Virtual learning environments (VLE) structure written learning through routes provided by virtual guides or teachers, this being a strict measure for interoperability with study participants. However, little is known about its interactive functionality among the participants who communicate on the platforms that configure these environments, for which, we investigated the effects that the VAS produced in the written expression of 30 subjects of secondary education in the capital of Peru. We design a research with a quantitative approach of a pre-experimental type, in which we use qualification sheets of the written production. The results report that the subjects participating in the experiment developed the capacity for written expression. This effect was developed in the largest number of subjects, who demonstrated improvements in the dimension of text adaptation and continuous evaluation of writing. The events witnessed allow us to argue that virtual learning environments grant freedom for creativity in writing, which has regulated in students the ability to write through social interactions exercised on the platforms in which they participated.Los entornos virtuales de aprendizaje (EVA) estructuran el aprendizaje escrito mediante rutas brindadas por los guías o docentes virtuales, siendo esta una medida estricta para la interoperabilidad con los participantes del estudio. Sin embargo, poco se conoce sobre su funcionalidad interactiva entre los participantes que se comunican en las plataformas que configuran estos entornos, por lo cual, indagamos los efectos que produjeron los EVA en la expresión escrita de 30 sujetos de educación secundaria de la capital del Perú. Diseñamos una investigación con enfoque cuantitativo de tipo pre experimental, en la cual, utilizamos fichas de calificación de la producción escrita. Los resultados reportan que los sujetos participantes en el experimento desarrollaron la capacidad de expresión escrita. Este efecto fue desarrollado en la mayor cantidad de sujetos quienes demostraron mejorías en la dimensión adecuación del texto y evaluación continua de la escritura. Los eventos presenciados permiten aducir que los entornos virtuales de aprendizaje otorgan libertad para la creatividad en la escritura, lo cual ha regulado en los estudiantes la capacidad para escribir mediante interacciones sociales ejercidas en las plataformas en que participaron

    Identification of a Likely Radio Counterpart of the Rapid Burster

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    We have identified a likely radio counterpart to the low-mass X-ray binary MXB 1730-335 (the Rapid Burster). The counterpart has shown 8.4 GHz radio on/off behavior correlated with the X-ray on/off behavior as observed by the RXTE/ASM during six VLA observations. The probability of an unrelated, randomly varying background source duplicating this behavior is 1-3% depending on the correlation time scale. The location of the radio source is RA 17h 33m 24.61s; Dec -33d 23' 19.8" (J2000), +/- 0.1". We do not detect 8.4 GHz radio emission coincident with type II (accretion-driven) X-ray bursts. The ratio of radio to X-ray emission during such bursts is constrained to be below the ratio observed during X-ray persistent emission at the 2.9-sigma level. Synchrotron bubble models of the radio emission can provide a reasonable fit to the full data set, collected over several outbursts, assuming that the radio evolution is the same from outburst to outburst, but given the physical constraints the emission is more likely to be due to ~hour-long radio flares such as have been observed from the X-ray binary GRS 1915+105.Comment: 28 pages, 4 figures; accepted for publication in ApJ (no changes

    Multifrequency spectra of solar brightness temperature derived from eclipse observations

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    Changes in solar radio-brightness temperature were derived at 2.8,19.3 and 22.2 GHz from the observations of radio flux during the total eclipse of 1980 February 16. High-resolution MEM spectra of the brightness temperature fluctuations at the three frequencies showed periodicities ranging from 3.5 min to 128 min. Between 3.5 min and 14.6 min there are several periodicities of comparable significance common to the three operating frequencies. If the corresponding variations in brightness temperature are assumed to result from spatial variations in the solar radio emission, the observed periodicities imply scale sizes in the range 76000 km to 320000 km

    Multi-Frequency observations of radio sun during total solar eclipse of February 16, 1980

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    Measurements of radio flux of the Sun duirng the total solar eclipse on February 16, 1980 were made from the Japal-Rangapur Observatory near Hyderabad, at radio frequencies of 2.8, 10, 19 and 22.2 GHz. Observations for both ingress and egress are available. Residual fluxesat totality for 2.8, 10 and 19 GHz were 23, 3.5 and 3 per cent respectively. The minimum fluxes were observed from 2 to 7 minutes prior to the mid-eclipse

    PfMFR3: A multidrug-resistant modulator in Plasmodium falciparum

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    In malaria, chemical genetics is a powerful method for assigning function to uncharacterized genes. MMV085203 and GNF-Pf-3600 are two structurally related napthoquinone phenotypic screening hits that kill both blood- and sexual-stag

    Determinants at the N- and C-termini of G¿ 12 required for activation of Rho-mediated signaling

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    Abstract Background Heterotrimeric guanine nucleotide binding proteins of the G12/13 subfamily, which includes the α-subunits Gα12 and Gα13, stimulate the monomeric G protein RhoA through interaction with a distinct subset of Rho-specific guanine nucleotide exchange factors (RhoGEFs). The structural features that mediate interaction between Gα13 and RhoGEFs have been examined in crystallographic studies of the purified complex, whereas a Gα12:RhoGEF complex has not been reported. Several signaling responses and effector interactions appear unique to Gα12 or Gα13, despite their similarity in amino acid sequence. Methods To comprehensively examine Gα12 for regions involved in RhoGEF interaction, we screened a panel of Gα12 cassette substitution mutants for binding to leukemia-associated RhoGEF (LARG) and for activation of serum response element mediated transcription. Results We identified several cassette substitutions that disrupt Gα12 binding to LARG and the related p115RhoGEF. These Gα12 mutants also were impaired in activating serum response element mediated signaling, a Rho-dependent response. Most of these mutants matched corresponding regions of Gα13 reported to contact p115RhoGEF, but unexpectedly, several RhoGEF-uncoupling mutations were found within the N- and C-terminal regions of Gα12. Trypsin protection assays revealed several mutants in these regions as retaining conformational activation. In addition, charge substitutions near the Gα12 N-terminus selectively disrupted binding to LARG but not p115RhoGEF. Conclusions Several structural aspects of the Gα12:RhoGEF interface differ from the reported Gα13:RhoGEF complex, particularly determinants within the C-terminal α5 helix and structurally uncharacterized N-terminus of Gα12. Furthermore, key residues at the Gα12 N-terminus may confer selectivity for LARG as a downstream effector
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