498 research outputs found

    A Sphere-Scanning Radiometer for Rapid Directional Measurements of Sky and Ground Radiance: the PARABOLA Field Instrument

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    A unique field instrument, called the PARABOLA, a collapsable support boom, which is self contained and easily transportable to remote sites to enable the acquisition of radiance data for almost the complete (4 pi) sky and ground-looking hemispheres in only 11 seconds was designed. The PARABOLA samples in 15 deg instantaneous field of view sectors in three narrow bandpass spectral channels simultaneously. Field measurement on a variety of earth surface cover types using a truck boom, a specially designed pickup truck mounting system, and a hot air balloon were studied. The PARABOLA instrument has potential for climatological and other studies which require characterization of the distribution of diffuse solar radiation within the sky hemisphere

    The A+B -> 0 annihilation reaction in a quenched random velocity field

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    Using field-theoretic renormalization group methods the long-time behaviour of the A+B -> 0 annihilation reaction with equal initial densities n_A(0) = n_B(0) = n_0 in a quenched random velocity field is studied. At every point (x, y) of a d-dimensional system the velocity v is parallel or antiparallel to the x-axis and depends on the coordinates perpendicular to the flow. Assuming that v(y) have zero mean and short-range correlations in the y-direction we show that the densities decay asymptotically as n(t) ~ A n_0^(1/2) t^(-(d+3)/8) for d<3. The universal amplitude A is calculated at first order in \epsilon = 3-d.Comment: 19 pages, LaTeX using IOP-macros, 5 eps-figures. It is shown that the amplitude of the density is universal, i.e. independent of the reaction rat

    Applied regional monitoring of the vernal advancement and retrogradation (Green wave effect) of natural vegetation in the Great Plains corridor

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    The author has identified the following significant results. LANDSAT 2 has shown that digital data products can be effectively employed on a regional basis to monitor changes in vegetation conditions. The TV16 was successfully applied to an extended test site and the Great Plains Corridor in tests of the ability to assess green forage biomass on rangelands as an index to vegetation condition. A strategy for using TV16 on a regional basis was developed and tested. These studies have shown that: (1) for rangelands with good vegetative cover, such as most of the Great Plains, and which are not heavily infested with brush or undesirable weed species, the LANDSAT digital data can provide a good estimate (within 250 kg/ha) of the quantity of green forage biomass, and (2) at least five levels of pasture and range feed conditions can be adequately mapped for extended regions

    A ‘near‐life experience’: lived experiences of spirituality from the perspective of people who have been subject to inpatient psychiatric care

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    Aims: To describe lived experiences of spirituality from the perspective of people who have been subject to inpatient psychiatric care and to interpret these experiences from an understanding of health as dialectical. Methods: After approval from a regional ethical board,eleven participants were recruited from two organisations for people with mental health problems. Participants were asked to narrate about spiritual experiences and occasions where such experiences had come close. The transcribed interviews were analysed by means of a phenomenological hermeneutical approach. Findings: A structural analysis of the text resulted in three themes; perceiving the presence of something extra mundane, making sense of reality and struggling for acceptance. The comprehensive understanding highlights spiritual experiences as going beyond religion, even though religious experiences appear as part of it. These experiences can indeed be a resource contributing to experiences of hope, connectedness, meaning and coherence in life. However, they can also give rise to doubt, anxiety and feelings of loneliness and hopelessness. Rather than understanding spiritual experiences as being either ‘good’ or ‘bad’, we could approach spirituality as something that is always present in alternate and inter-related forms. Metaphorically, this could be understood as a ‘near-life experience’, summarising participants’experiences related to their struggle with issues related to suffering and health which are simultaneously present. Conclusions: If psychiatric nurses could approach this complexity and, without being judgemental, explore seemingly positive and negative experiences of spirituality as dialectically related to each other, rather than viewing them as either resources or problems, this could contribute to insiderness care and hopefully also support people who struggle with these experiences to seek help when needed

    Pectic Oligosaccharides from Cranberry Prevent Quiescence and Persistence in the Uropathogenic Escherichia coli CFT073

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    Urinary tract infections (UTIs) caused by Escherichia coli create a large burden on healthcare and frequently lead to recurrent infections. Part of the success of E. coli as an uropathogenic bacterium can be attributed to its ability to form quiescent intracellular reservoirs in bladder cells and its persistence after antibiotic treatment. Cranberry juice and related products have been used for the prevention of UTIs with varying degrees of success. In this study, a group of cranberry pectic oligosaccharides (cPOS) were found to both inhibit quiescence and reduce the population of persister cells formed by the uropathogenic strain, CFT073. This is the first report detailing constituents of cranberry with the ability to modulate these important physiological aspects of uropathogenic E. coli. Further studies investigating cranberry should be keen to include oligosaccharides as part of the ‘active’ cocktail of chemical compounds

    Rhizoleucinoside, a Rhamnolipid–Amino Alcohol Hybrid from the Rhizobial Symbiont \u3cem\u3eBradyrhizobium\u3c/em\u3e sp. BTAi1

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    Rhizoleucinoside (1), a unique rhamnolipid–amino alcohol hybrid, was isolated from the rhizobial symbiont bacterium Bradyrhizobium sp. BTAi1. Compound 1 features a rare rhamnolipid core attached to an unprecedented leucinol moiety. Its structure and absolute configuration were determined by spectroscopic analysis, tandem mass spectrometry, chemical degradation, and application of the Marfey’s method. Compound 1 possesses moderate cytotoxicity to BV-2 murine microglia and highly aggressive proliferating immortalized (HAPI) rat microglia cells

    N-Acyl Dehydrotyrosines, Typrosinase Inhibitors from the Marine Bacteriu, Thalasssotalea sp. PP2-459

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    Thalassotalic acids A–C and thalassotalamides A and B are new N-acyl dehydrotyrosine derivatives produced by Thalassotalea sp. PP2-459, a Gram-negative bacterium isolated from a marine bivalve aquaculture facility. The structures were elucidated via a combination of spectroscopic analyses emphasizing two-dimensional NMR and high-resolution mass spectrometric data. Thalassotalic acid A (1) displays in vitro inhibition of the enzyme tyrosinase with an IC50 value (130 ÎŒM) that compares favorably to the commercially used control compounds kojic acid (46 ÎŒM) and arbutin (100 ÎŒM). These are the first natural products reported from a bacterium belonging to the genus Thalassotalea

    Observations of a novel predatory gull behavior on an invasive ascidian: A new consequence of coastal urban sprawl?

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    Coastal urbanization has a dramatic effect on both terrestrial and marine ecosystems, altering resources such as food or space. Many species have shifted their ranges in response to anthropogenic pressures, resulting in novel species interactions. Here, we report an observation of a novel foraging behavior of the European Herring Gull (Larus argentatus): the capture and consumption of the widespread sea squirt Ciona intestinalis from under floating pontoons in a recreational marina in Ireland. Multiple gulls were observed performing a complex, multi‐step manipulation of several C. intestinalis individuals to remove their cellulose‐based tunic, which remained unconsumed. Further avenues of investigation are discussed, and hypotheses concerning possible ecosystem effects of novel ecological interactions occurring in proliferating artificial environments are presented
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