2,932 research outputs found

    Redundant Discrete Wavelet Transform Based Super-Resolution Using Sub-Pixel Image Registration

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    The limited resolution of video imagery taken by aircraft, over geographical areas of interest, hinders the accurate extraction of useful information. The frame resolution of the video is determined by the camera that created it. Information exists about the camera which can be used to increase frame resolution beyond the resolution capability of the camera. This is achieved by a process called super-resolution, which uses multiple low-resolution video frames to create one high-resolution image

    The disconnect between animal models of sepsis and human sepsis

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141189/1/jlb0137.pd

    The Excitation of N2_2H+^+ in Interstellar Molecular Clouds. I - Models

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    We present LVG and non-local radiative transfer calculations involving the rotational and hyperfine structure of the spectrum of N2_2H+^+ with collisional rate coefficients recently derived by us. The goal of this study is to check the validity of the assumptions made to treat the hyperfine structure and to study the physical mechanisms leading to the observed hyperfine anomalies. We find that the usual hypothesis of identical excitation temperatures for all hyperfine components of the JJ=1-0 transition is not correct within the range of densities existing in cold dense cores, i.e., a few 104^4 \textless n(H2_2) \textless a few 106^6 cm−3^{-3}. This is due to different radiative trapping effects in the hyperfine components. Moreover, within this range of densities and considering the typical abundance of N2_2H+^+, the total opacity of rotational lines has to be derived taking into account the hyperfine structure. The error made when only considering the rotational energy structure can be as large as 100%. Using non-local models we find that, due to saturation, hyperfine anomalies appear as soon as the total opacity of the JJ=1-0 transition becomes larger than ≃\simeq 20. Radiative scattering in less dense regions enhance these anomalies, and particularly, induce a differential increase of the excitation temperatures of the hyperfine components. This process is more effective for the transitions with the highest opacities for which emerging intensities are also reduced by self-absorption effects. These effects are not as critical as in HCO+^+ or HCN, but should be taken into account when interpreting the spatial extent of the N2_2H+^+ emission in dark clouds.Comment: 13 pages, 12 figure

    Physicochemical Characteristics and Macroinvertebrate Assemblages of Riffles Upstream and Downstream of a Streambank Impacted by Unrestricted Cattle Access

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    Riparian zones are important contributors to stream ecosystem health. Alteration of such areas can change stream structure and function, resulting in modified productivity and hydrologic patterns. We studied two riffle sites on the South Fork of the Spring River in Fulton County, AR upstream and downstream of a streambank ostensibly degraded by unrestricted cattle access. The two sites were measured for differences in physical habitat (including bank width, stream velocity, depth, substrate composition, and embeddedness), chemical characteristics (including dissolved oxygen, pH, conductivity, turbidity and total suspended solids) and biological characteristics (including benthic macroinvertebrate community composition, similarity, and standing crop). Measurements were conducted quarterly for one year. We found embeddedness, total suspended solids and turbidity to be significantly higher downstream of the cattle access area. Community metrics were similar for both sites; however, macroinvertebrate standing crop was lower downstream. These results suggest moderate differences in stream productivity downstream of the cattle access site. Future work will evaluate whether reduced cattle access and streambank stabilization efforts result in improvements in water quality and density of macroinvertebrates

    Behaviors of Adult \u3ci\u3eAgrilus Planipennis\u3c/i\u3e (Coleoptera: Buprestidae)

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    A 2-year study was conducted in Canada (2003) and the United States (2005) to better understand searching and mating behaviors of adult Agrilus planipennis Fairmaire. In both field and laboratory, adults spent more time resting and walking than feeding or flying. The sex ratio in the field was biased towards males, which tended to hover around trees, likely looking for mates. There was more leaf feeding damage within a tree higher in the canopy than in the lower canopy early in the season, but this difference disappeared over time. In choice experiments, males attempted to mate with individuals of both sexes, but they landed more frequently on females than on males. A series of sexual behaviors was observed in the laboratory, including: exposure of the ovipositor/genitalia, sporadic jumping by males, attempted mating, and mating. Sexual behaviors were absent among 1-3 day-old beetles, but were observed regularly in 10-12 day-old beetles. Females were seen exposing their ovipositor, suggestive of pheromone-calling behavior. No courtship was observed prior to mating. Hovering, searching, and landing behaviors suggest that beetles most likely rely on visual cues during mate finding, although host-plant volatiles and/or pheromones might also be involved

    How to find discrete contact symmetries

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    This paper describes a new algorithm for determining all discrete contact symmetries of any differential equation whose Lie contact symmetries are known. The method is constructive and is easy to use. It is based upon the observation that the adjoint action of any contact symmetry is an automorphism of the Lie algebra of generators of Lie contact symmetries. Consequently, all contact symmetries satisfy various compatibility conditions. These conditions enable the discrete symmetries to be found systematically, with little effort

    Binding modes of high stoichiometry guest complexes with a Co8L12 cage uncovered by mass spectrometry

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    We demonstrate how different modes of guest binding with a Co8L12 cubic cage can be determined using ESI-MS. High stoichiometry guest binding was observed, with the guests preferentially binding externally, but internal guest inclusion was also seen at higher guest loading

    A High-Density Linkage Map of the Ancestral Diploid Strawberry, Fragaria iinumae, Constructed with Single Nucleotide Polymorphism Markers from the IStraw90 Array and Genotyping by Sequencing

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    Fragaria iinumae Makino is recognized as an ancestor of the octoploid strawberry species, which includes the cultivated strawberry, Fragaria ×ananassa Duchesne ex Rozier. Here we report the construction of the first high-density linkage map for F. iinumae. The F. iinumae linkage map (Fii map) is based on two high-throughput techniques of single nucleotide polymorphism (SNP) genotyping: the IStraw90 Array (hereafter “Array”), and genotyping by sequencing (GBS). The F2 generation mapping population was derived by selfing F. iinumae hybrid F1D, the product of a cross between two divergent F. iinumae accessions collected from Hokkaido, Japan. The Fii map consists of seven linkage groups (LGs) and has an overall length of 451.7 cM as defined by 496 loci populated by 4173 markers: 3280 from the Array and 893 from GBS. Comparisons with two versions of the Fragaria vesca ssp. vesca L. ‘Hawaii 4’ pseudo-chromosome (PC) assemblies reveal substantial conservation of synteny and colinearity, yet identified differences that point to possible genomic divergences between F. iinumae and F. vesca, and/or to F. vesca genomic assembly errors. The Fii map provides a basis for anchoring a F. iinumae genome assembly as a prerequisite for constructing a second diploid reference genome for Fragaria

    Polarization mode dispersion compensator field trial and field fiber characterization

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    Two high-PMD long distance routes were characterized and used to test an optical polarization mode dispersion compensator (PMDC) under field conditions. For this trial, 110 km routes with mean PMD values of 25 and 26.5 ps were provisioned with commercial WDM transport equipment and tested for several weeks. The route was comprised of three spans of characterized fiber that followed railroad tracks. We show the temporal variation of the output polarization state and the evolution of first- and second-order PMD spectra over 7 days. The deployment of a variable-length PMDC on these links allowed error-free transmission of an OC-192 signal. Splitting the output to receivers with and without PMDC demonstrated specific PMD events that caused errors in the absence of a PMDC. (C) 2002 Optical Society of America
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