863 research outputs found

    The 27-28 October 1986 FIRE IFO Cirrus Case Study: Cloud Optical Properties Determined by High Spectral Resolution Lidar

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    During the First ISCCP Region Experiment (FIRE) cirrus intensive field observation (IFO) the High Spectral Resolution Lidar was operated from a roof top site on the University of Wisconsin-Madison campus. Because the HSRL technique separately measures the molecular and cloud particle backscatter components of the lidar return, the optical thickness is determined independent of particle backscatter. This is accomplished by comparing the known molecular density distribution to the observed decrease in molecular backscatter signal with altitude. The particle to molecular backscatter ratio yields calibrated measurements of backscatter cross sections that can be plotted ro reveal cloud morphology without distortion due to attenuation. Changes in cloud particle size, shape, and phase affect the backscatter to extinction ratio (backscatter-phase function). The HSRL independently measures cloud particle backscatter phase function. This paper presents a quantitative analysis of the HSRL cirrus cloud data acquired over an approximate 33 hour period of continuous near zenith observations. Correlations between small scale wind structure and cirrus cloud morphology have been observed. These correlations can bias the range averaging inherent in wind profiling lidars of modest vertical resolution, leading to increased measurement errors at cirrus altitudes. Extended periods of low intensity backscatter were noted between more strongly organized cirrus cloud activity. Optical thicknesses ranging from 0.01-1.4, backscatter phase functions between 0.02-0.065 sr (exp -1) and backscatter cross sections spanning 4 orders of magnitude were observed. the altitude relationship between cloud top and bottom boundaries and the cloud optical center altitude was dependent on the type of formation observed Cirrus features were observed with characteristic wind drift estimated horizontal sizes of 5-400 km. The clouds frequently exhibited cellular structure with vertical to horizontal dimension ratios of 1:5-1:1

    Home Manufacture of Drugs: An Online Investigation and a Toxicological Reality Check of Online Discussions on Drug Chemistry

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    Emerging trends in market dynamics and the use of new psychoactive substances are both a public health concern and a complex regulatory issue. One novel area of investigation is the availability of homemade opioids, amphetamines and dissociatives, and the potential fueling of interest in clandestine home manufacture of drugs via the Internet. We illustrate here how online communal folk pharmacology of homemade drugs on drug website forums may actually inform home manufacture practices or contribute to the reduction of harms associated with this practice. Discrepancies between online information around purification and making homemade drugs safer, and the synthesis of the same substances in a proper laboratory environment, exist. Moderation and shutdown of synthesis queries and discussions online are grounded in drug websites adhering to harm-reduction principles by facilitating discussions around purification of homemade drugs only. Drug discussion forums should consider reevaluating their policies on chemistry discussions in aiming to reach people who cannot or will not refrain from cooking their own drugs with credible information that may contribute to reductions in the harms associated with this practice. © 2017 Taylor & Francis Group, LL

    Quantification of serotonin and eight of its metabolites in plasma of healthy volunteers by mass spectrometry.

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    Serotonin is transformed into melatonin under the control of the light/dark cycle, representing a cornerstone of circadian rhythmicity. Serotonin also undergoes extensive metabolism to produce 5-hydroxyindoleacetic acid (5-HIAA), a biomarker for the diagnosis and monitoring of serotonin secreting neuroendocrine tumors (NETs). While serotonin, melatonin and their metabolites are part of an integrated comprehensive system, human observations about their respective plasma concentrations are still limited. We report here for the first time a multiplex UHPLC-MS/MS assay for the quantification of serotonin, 5-HIAA, 5-hydroxytryptophol (5-HTPL), N-acetyl-serotonin (NAS), Mel, 6-OH-Mel, 5-methoxytryptamine (5-MT), 5-methoxytryptophol (5-MTPL), and 5-methoxyindoleacetic acid (5-MIAA) in human plasma. Analytes were extracted by protein precipitation and solid phase extraction. Plasma concentrations for these analytes were determined in 102 healthy volunteers. The LLOQ of the assay ranges from 2.2 nM for serotonin to 1.0 pM for 6-OH-Mel. This sensitivity enables the quantification of circulating serotonin, 5-HIAA, NAS, Mel, and 5-MIAA, even at their lowest diurnal concentrations. This assay will enable specific, precise and accurate measurement of serotonin, Mel and their metabolites to draw a detailed picture of this complex pineal metabolism, allowing a dynamic understanding of these pathways and providing promising biomarkers and a metabolic signature for serotonin-secreting NETs

    Leading-effect vs. Risk-taking in Dynamic Tournaments: Evidence from a Real-life Randomized Experiment

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    Two 'order effects' may emerge in dynamic tournaments with information feedback. First, participants adjust effort across stages, which could advantage the leading participant who faces a larger 'effective prize' after an initial victory (leading-effect). Second, participants lagging behind may increase risk at the final stage as they have 'nothing to lose' (risk-taking). We use a randomized natural experiment in professional two-game soccer tournaments where the treatment (order of a stage-specific advantage) and team characteristics, e.g. ability, are independent. We develop an identification strategy to test for leading-effects controlling for risk-taking. We find no evidence of leading-effects and negligible risk-taking effects

    Post-stroke inhibition of induced NADPH oxidase type 4 prevents oxidative stress and neurodegeneration

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    Ischemic stroke is the second leading cause of death worldwide. Only one moderately effective therapy exists, albeit with contraindications that exclude 90% of the patients. This medical need contrasts with a high failure rate of more than 1,000 pre-clinical drug candidates for stroke therapies. Thus, there is a need for translatable mechanisms of neuroprotection and more rigid thresholds of relevance in pre-clinical stroke models. One such candidate mechanism is oxidative stress. However, antioxidant approaches have failed in clinical trials, and the significant sources of oxidative stress in stroke are unknown. We here identify NADPH oxidase type 4 (NOX4) as a major source of oxidative stress and an effective therapeutic target in acute stroke. Upon ischemia, NOX4 was induced in human and mouse brain. Mice deficient in NOX4 (Nox4(-/-)) of either sex, but not those deficient for NOX1 or NOX2, were largely protected from oxidative stress, blood-brain-barrier leakage, and neuronal apoptosis, after both transient and permanent cerebral ischemia. This effect was independent of age, as elderly mice were equally protected. Restoration of oxidative stress reversed the stroke-protective phenotype in Nox4(-/-) mice. Application of the only validated low-molecular-weight pharmacological NADPH oxidase inhibitor, VAS2870, several hours after ischemia was as protective as deleting NOX4. The extent of neuroprotection was exceptional, resulting in significantly improved long-term neurological functions and reduced mortality. NOX4 therefore represents a major source of oxidative stress and novel class of drug target for stroke therapy

    Sabotage in Contests: A Survey

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    A contest is a situation in which individuals expend irretrievable resources to win valuable prize(s). ‘Sabotage’ is a deliberate and costly act of damaging a rival’s' likelihood of winning the contest. Sabotage can be observed in, e.g., sports, war, promotion tournaments, political or marketing campaigns. In this article, we provide a model and various perspectives on such sabotage activities and review the economics literature analyzing the act of sabotage in contests. We discuss the theories and evidence highlighting the means of sabotage, why sabotage occurs, and the effects of sabotage on individual players and on overall welfare, along with possible mechanisms to reduce sabotage. We note that most sabotage activities are aimed at the ablest player, the possibility of sabotage reduces productive effort exerted by the players, and sabotage may lessen the effectiveness of public policies, such as affirmative action, or information revelation in contests. We discuss various policies that a designer may employ to counteract sabotage activities. We conclude by pointing out some areas of future research

    Fungal model systems and the elucidation of pathogenicity determinants

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    This is the final version of the article. Available from Elsevier via the DOI in this record.Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. These include pathogens of both animals and plants; Ashbya gossypii, Aspergillus fumigatus, Candida albicans, Fusarium oxysporum, Magnaporthe oryzae, Ustilago maydis and Zymoseptoria tritici. We present key insights into the virulence mechanisms deployed by each species and a comparative overview of key insights obtained from genomic analysis. We then consider current trends and future challenges associated with the study of fungal pathogenicity.This review was carried out by members of the EU-Initial Training Network Ariadne (PITN-GA-2009-237936), which provided financial support for C.B., S.D., M.E.G., E.G., E.M., P.V.M., M.M., V.N., M.F.A.N., T.O., M.O.R., K.S. and L.W

    Lack of virological and serological evidence for continued circulation of highly pathogenic avian influenza H5N8 virus in wild birds in the Netherlands, 14 November 2014 to 31 January 2016

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    In 2014, H5N8 clade 2.3.4.4 highly pathogenic avian influenza (HPAI) viruses of the A/Goose/ Guangdong/1/1996 lineage emerged in poultry and wild birds in Asia, Europe and North America. Here, wild birds were extensively investigated in the Netherlands for HPAI H5N8 virus (real-time polymerase chain reaction targeting the matrix and H5 gene) and antibody detection (haemagglutination inhibition and virus neutralisation assays) before, during and after the first virus detection in Europe in late 2014. Between 21 February 2015 and 31 January 2016, 7,337 bird samples were tested for the virus. One HPAI H5N8 virus-infected Eurasian wigeon (Anas penelope) sampled on 25 February 2015 was detected. Serological assays were performed on 1,443 samples, including 149 collected between 2007 and 2013, 945 between 14 November 2014 and 13 May 2015, and 349 between 1 September and 31 December 2015. Antibodies specific for HPAI H5 clade 2.3.4.4 were absent in wild bird sera obtained before 2014 and present in sera collected during and after the HPAI H5N8 emergence in Europe, with antibody incidence declining after the 2014/15 winter. Our results indicate that the HPAI H5N8 virus has not continued to circulate extensively in wild bird populations since the 2014/15 winter and that independent maintenance of the virus in these populations appears unlikely
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