1,180 research outputs found

    Clearcutting and shearing on a saline soil in East Texas: Impacts on soil physical properties

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    Soil samples, or in-situ measurements, were collected at seven occasions and at six depths to study the Impact of three forest conditions on soil physical properties of a saline soil in E. Texas. Soil bulk density, CW. of silt plus clay at the surface horizons, soil water content, soil water retention, and depth to groundwater Increased following intensive site preparation. Differences in these properties between the commercial clearcuttlng and undisturbed forest were small. The wet soil conditions created in the Intensive preparation site are not likely to be responsible for the failure of artificial pine regeneration. In areas where site preparation may cause standing water on the surface, all plants and stumps should be left intact after marketable timber is removed

    The efficacy and mechanism of peripheral opioids in paediatric inflammatory pain.

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    Background: The management of pain in children is a common but difficult symptom to treat and the use of strong analgesics is often limited, for a variety of reasons, including fear of inducing side effects. Morphine is normally considered to be a centrally acting analgesic but recently, the beneficial effects of peripheral opioids have been demonstrated in adults for a number of painful inflammatory conditions. When administered in this non invasive way, opioids provide analgesia without achieving significant plasma concentrations and therefore it can be assumed that many of the adverse effects associated with oral or systemic opioids are avoided. Methods: A) The first part of the thesis describes the mechanism of action of peripheral opioids through development and particularly their effect during inflammation. This work was conducted using different ages of Sprague Dawley rat pups and skin inflammation was induced using carageenan. B) The second section is a description of a double-blinded, randomised-controlled, placebo-controlled trial with crossover design, to assess the efficacy of peripheral opioids in paediatric inflammatory pain. This was conducted in children with a diagnosis of Epidermolysis Bullosa (EB), as a model for acute and chronic inflammatory pain Results:. The laboratory study demonstrates that mu opioid receptor (MOR) expression is up regulated in neonatal plantar skin and significantly up regulated in neonatal lumbar dorsal root ganglion (DRG) four hours post hind paw inflammation, MOR protein levels in the rat hind paw plantar skin are significantly up regulated post-natally, and MOR protein levels are significantly up regulated in both neonatal and young adult plantar skin four hours post hind paw inflammation. Clinically, pain reduction was most significant with background pain Conclusion: The developmental regulation of peripheral MOR both in naive and inflamed cutaneous tissue may have implications for the use of topically / peripherally applied opioids in infants and children. "I, Gillian Watterson confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis"

    Management and pest management considerations on droughty soils: four year results

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    Four year survival of pines on droughty (Typic Quartzips~mments) soils was best for longleaf pine and Terr-Sorb -treated loblolly pine. Pest considerations include town ants and Nantucket pine tip moths on loblolly pine. Untreated loblolly pine had reduced leader and total height growth anH increased tip moth infestations, compared to Terra-Sorb and clay-slurry treated loblolly pine. Soil texture averaged less than eight percent silt and clay combined in the treatment areas

    A role for water in cell structure

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    Forestry Bulletin No. 25: Silviculture of Southern Bottomland Hardwoods

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    The potential of southern bottomland hardwood types is clear, for they, along with the cypress, occupy about 37 million acres and compromise more than half of the hardwood stumpage in the south.https://scholarworks.sfasu.edu/forestrybulletins/1021/thumbnail.jp

    Mr. and Mrs. G. T. Watterson to The Chairman Board of Trustees Ole Miss, 19 September 1962

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    The Wattersons urge the board to support Governor Barnett.https://egrove.olemiss.edu/west_union_um/1018/thumbnail.jp

    Statistics of selectively neutral genetic variation

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    Random models of evolution are instrumental in extracting rates of microscopic evolutionary mechanisms from empirical observations on genetic variation in genome sequences. In this context it is necessary to know the statistical properties of empirical observables (such as the local homozygosity for instance). Previous work relies on numerical results or assumes Gaussian approximations for the corresponding distributions. In this paper we give an analytical derivation of the statistical properties of the local homozygosity and other empirical observables assuming selective neutrality. We find that such distributions can be very non-Gaussian.Comment: 4 pages, 4 figure

    Reversal Distances for Strings with Few Blocks or Small Alphabets

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    International audienceWe study the String Reversal Distance problem, an extension of the well-known Sorting by Reversals problem. String Reversal Distance takes two strings S and T as input, and asks for a minimum number of reversals to obtain T from S. We consider four variants: String Reversal Distance, String Prefix Reversal Distance (in which any reversal must include the first letter of the string), and the signed variants of these problems, namely Signed String Reversal Distance and Signed String Prefix Reversal Distance. We study algorithmic properties of these four problems, in connection with two parameters of the input strings: the number of blocks they contain (a block being maximal substring such that all letters in the substring are equal), and the alphabet size ÎŁ. For instance, we show that Signed String Reversal Distance and Signed String Prefix Reversal Distance are NP-hard even if the input strings have only one letter

    Differential transactivation of sphingosine-1-phosphate receptors modulates NGF-induced neurite extension

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    The process of neurite extension after activation of the TrkA tyrosine kinase receptor by nerve growth factor (NGF) involves complex signaling pathways. Stimulation of sphingosine kinase 1 (SphK1), the enzyme that phosphorylates sphingosine to form sphingosine-1-phosphate (S1P), is part of the functional TrkA signaling repertoire. In this paper, we report that in PC12 cells and dorsal root ganglion neurons, NGF translocates SphK1 to the plasma membrane and differentially activates the S1P receptors S1P1 and S1P2 in a SphK1-dependent manner, as determined with specific inhibitors and small interfering RNA targeted to SphK1. NGF-induced neurite extension was suppressed by down-regulation of S1P1 expression with antisense RNA. Conversely, when overexpressed in PC12 cells, transactivation of S1P1 by NGF markedly enhanced neurite extension and stimulation of the small GTPase Rac, important for the cytoskeletal changes required for neurite extension. Concomitantly, differentiation down-regulated expression of S1P2 whose activation would stimulate Rho and inhibit neurite extension. Thus, differential transactivation of S1P receptors by NGF regulates antagonistic signaling pathways that modulate neurite extension

    Pattern scaling using ClimGen: monthly-resolution future climate scenarios including changes in the variability of precipitation

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    Development, testing and example applications of the pattern-scaling approach for generating future climate change projections are reported here, with a focus on a particular software application called “ClimGen”. A number of innovations have been implemented, including using exponential and logistic functions of global-mean temperature to represent changes in local precipitation and cloud cover, and interpolation from climate model grids to a finer grid while taking into account land-sea contrasts in the climate change patterns. Of particular significance is a new approach for incorporating changes in the inter-annual variability of monthly precipitation simulated by climate models. This is achieved by diagnosing simulated changes in the shape of the gamma distribution of monthly precipitation totals, applying the pattern-scaling approach to estimate changes in the shape parameter under a future scenario, and then perturbing sequences of observed precipitation anomalies so that their distribution changes according to the projected change in the shape parameter. The approach cannot represent changes to the structure of climate timeseries (e.g. changed autocorrelation or teleconnection patterns) were they to occur, but is shown here to be more successful at representing changes in low precipitation extremes than previous pattern-scaling methods
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