4,863 research outputs found

    Oreoporanthera, a New Zealand "endemic" plant genus discovered in Tasmania

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    Recent collections near Mt Anne in southwestern Tasmania have extended the known range of the previously monotypic New Zealand endemic genus Oreoporanthera to this island. The Tasmanian plants differ from New Zealand's O. a/pina in a number of floral and vegetative characters and are considered to represent a new species 0. peta/ifera. Like O. a/pina, O. peta/ifera is found on calcareous montane outcrops and the two are clearly closely allied

    Metastable Flux Configurations and de Sitter Spaces

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    We derive stability conditions for the critical points of the no-scale scalar potential governing the dynamics of the complex structure moduli and the axio-dilaton in compactifications of type IIB string theory on Calabi-Yau three-folds. We discuss a concrete example of a T^6 orientifold. We then consider the four-dimensional theory obtained from compactifications of type IIB string theory on non-geometric backgrounds which are mirror to rigid Calabi-Yau manifolds and show that the complex structure moduli fields can be stabilized in terms of H_{RR} only, i.e. with no need of orientifold projection. The stabilization of all the fields at weak coupling, including the axio-dilaton, may require to break supersymmetry in the presence of H_{NS} flux or corrections to the scalar potential.Comment: 24 page

    Found: High Surface Brightness Compact Galaxies

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    We are using the 2dF spectrograph to make a survey of all objects (`stars' and `galaxies') in a 12 sq.deg region towards the Fornax cluster. We have discovered a population of compact emission-line galaxies unresolved on photographic sky survey plates and therefore missing in most galaxy surveys based on such material. These galaxies are as luminous as normal field galaxies. Using H-alpha to estimate star formation they contribute at least an additional 5 per cent to the local star formation rate.Comment: To appear in "The Low Surface Brightness Universe", IAU Coll 171, eds. J.I. Davies et al., A.S.P. Conference Series. 3 pages, LaTex, 1 encapsulated ps-figure, requires paspconf.st

    Dosimetry of 3 CBCT devices for oral and maxillofacial radiology: CB Mercuray, NewTom 3G and i-CAT

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    Cone beam computed tomography (CBCT), which provides a lower dose, lower cost alternative to conventional CT, is being used with increasing frequency in the practice of oral and maxillofacial radiology. This study provides comparative measurements of effective dose for three commercially available, large (12'') field-of-view (FOV), CBCT units: CB Mercuray, NewTom 3G and i-CAT. Thermoluminescent dosemeters (TLDs) were placed at 24 sites throughout the layers of the head and neck of a tissue-equivalent human skull RANDO phantom. Depending on availability, the 12'' FOV and smaller FOV scanning modes were used with similar phantom positioning geometry for each CBCT unit. Radiation weighted doses to individual organs were summed using 1990 (E(1990)) and proposed 2005 (E(2005 draft)) ICRP tissue weighting factors to calculate two measures of whole-body effective dose. Dose as a multiple of a representative panoramic radiography dose was also calculated. For repeated runs dosimetry was generally reproducible within 2.5%. Calculated doses in microSv [corrected] (E(1990), E(2005 draft)) were NewTom3G (45, 59), i-CAT (135, 193) and CB Mercuray (477, 558). These are 4 to 42 times greater than comparable panoramic examination doses (6.3 microSv [corrected] 13.3 mSv). Reductions in dose were seen with reduction in field size and mA and kV technique factors. CBCT dose varies substantially depending on the device, FOV and selected technique factors. Effective dose detriment is several to many times higher than conventional panoramic imaging and an order of magnitude or more less than reported doses for conventional CT

    Low dose gamma irradiation does not affect the quality or total ascorbic acid concentration of “sweetheart” passionfruit (passiflora edulis)

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    Passionfruit (Passiflora edulis, Sims, cultivar “Sweetheart”) were subject to gamma irradiation at levels suitable for phytosanitary purposes (0, 150, 400 and 1000 Gy) then stored at 8 °C and assessed for fruit quality and total ascorbic acid concentration after one and fourteen days. Irradiation at any dose (≤1000 Gy) did not affect passionfruit quality (overall fruit quality, colour, firmness, fruit shrivel, stem condition, weight loss, total soluble solids level (TSS), titratable acidity (TA) level, TSS/TA ratio, juice pH and rot development), nor the total ascorbic acid concentration. The length of time in storage affected some fruit quality parameters and total ascorbic acid concentration, with longer storage periods resulting in lower quality fruit and lower total ascorbic acid concentration, irrespective of irradiation. There was no interaction between irradiation treatment and storage time, indicating that irradiation did not influence the effect of storage on passionfruit quality. The results showed that the application of 150, 400 and 1000 Gy gamma irradiation to “Sweetheart” purple passionfruit did not produce any deleterious effects on fruit quality or total ascorbic acid concentration during cold storage, thus supporting the use of low dose irradiation as a phytosanitary treatment against quarantine pests in purple passionfruit. © 2015 MDPI.Open access retrieved from: https://www.mdpi.com/2304-8158/4/3/37

    Spotting the diffusion of New Psychoactive Substances over the Internet

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    Online availability and diffusion of New Psychoactive Substances (NPS) represent an emerging threat to healthcare systems. In this work, we analyse drugs forums, online shops, and Twitter. By mining the data from these sources, it is possible to understand the dynamics of drugs diffusion and their endorsement, as well as timely detecting new substances. We propose a set of visual analytics tools to support analysts in tackling NPS spreading and provide a better insight about drugs market and analysis

    The nitroxide radical TEMPOL prevents obesity, hyperlipidaemia, elevation of inflammatory cytokines, and modulates atherosclerotic plaque composition in apoE<sup>-/-</sup> mice

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    © 2015 Elsevier Ireland Ltd. The nitroxide compound TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl radical) has been shown to prevent obesity-induced changes in adipokines in cell and animal systems. In this study we investigated whether supplementation with TEMPOL inhibits inflammation and atherosclerosis in apoE-/- mice fed a high fat diet (HFD). Methods: ApoE-/- mice were fed for 12 weeks on standard chow diet or a high-fat diet. Half the mice were supplemented with 10mg/g TEMPOL in their food. Plasma samples were analysed for triglycerides, cholesterol, low- and high-density lipoprotein cholesterol, inflammatory cytokines and markers (interleukin-6, IL-6; monocyte-chemotactic protein, MCP-1; myeloperoxidase, MPO; serum amyloid A, SAA; adiponectin; leptin). Plaques in the aortic sinus were analysed for area, and content of collagen, lipid, macrophages and smooth muscle cells. Results: High fat feeding resulted in marked increases in body mass and plasma lipid levels. Dietary TEMPOL decreased both parameters. In the high-fat-fed mice significant elevations in plasma lipid levels and the inflammatory markers IL-6, MCP-1, MPO, SAA were detected, along with an increase in leptin and a decrease in adiponectin. TEMPOL supplementation reversed these effects. When compared to HFD-fed mice, TEMPOL supplementation increased plaque collagen content, decreased lipid content and increased macrophage numbers. Conclusions: These data indicate that in a well-established model of obesity-associated hyperlipidaemia and atherosclerosis, TEMPOL had a significant impact on body mass, atherosclerosis, hyperlipidaemia and inflammation. TEMPOL may therefore be of value in suppressing obesity, metabolic disorders and increasing atherosclerotic plaque stability

    The effects of cannabidiol on impulsivity and memory during abstinence in cigarette dependent smokers

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    This is the final version of the article. Available from Springer Nature via the DOI in this record.The dataset generated during the current study are available from the corresponding author on reasonable request.Acute nicotine abstinence in cigarette smokers results in deficits in performance on specific cognitive processes, including working memory and impulsivity which are important in relapse. Cannabidiol (CBD), the non-intoxicating cannabinoid found in cannabis, has shown pro-cognitive effects and preliminary evidence has indicated it can reduce the number of cigarettes smoked in dependent smokers. However, the effects of CBD on cognition have never been tested during acute nicotine withdrawal. The present study therefore aimed to investigate if CBD can improve memory and reduce impulsivity during acute tobacco abstinence. Thirty, non-treatment seeking, dependent, cigarette smokers attended two laboratory-based sessions after overnight abstinence, in which they received either 800 mg oral CBD or placebo (PBO), in a randomised order. Abstinence was biologically verified. Participants were assessed on go/no-go, delay discounting, prose recall and N-back (0-back, 1-back, 2-back) tasks. The effects of CBD on delay discounting, prose recall and the N-back (correct responses, maintenance or manipulation) were null, confirmed by a Bayesian analysis, which found evidence for the null hypothesis. Contrary to our predictions, CBD increased commission errors on the go/no-go task. In conclusion, a single 800 mg dose of CBD does not improve verbal or spatial working memory, or impulsivity during tobacco abstinence.This research was funded by a PhD Studentship from the Medical Research Council (MRC) to the C.H. and an MRC DPFS award (MR/K015524/1) to HVC and CJAM.TPF is funded by a Senior Academic Fellowship from the Society for the Study of Addiction

    Chiral Polymerization in Open Systems From Chiral-Selective Reaction Rates

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    We investigate the possibility that prebiotic homochirality can be achieved exclusively through chiral-selective reaction rate parameters without any other explicit mechanism for chiral bias. Specifically, we examine an open network of polymerization reactions, where the reaction rates can have chiral-selective values. The reactions are neither autocatalytic nor do they contain explicit enantiomeric cross-inhibition terms. We are thus investigating how rare a set of chiral-selective reaction rates needs to be in order to generate a reasonable amount of chiral bias. We quantify our results adopting a statistical approach: varying both the mean value and the rms dispersion of the relevant reaction rates, we show that moderate to high levels of chiral excess can be achieved with fairly small chiral bias, below 10%. Considering the various unknowns related to prebiotic chemical networks in early Earth and the dependence of reaction rates to environmental properties such as temperature and pressure variations, we argue that homochirality could have been achieved from moderate amounts of chiral selectivity in the reaction rates.Comment: 15 pages, 6 figures, accepted for publication in Origins of Life and Evolution of Biosphere
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