3,639 research outputs found

    The length of the glaciers in the world:a straightforward method for the automated calculation of glacier center lines

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    Glacier length is an important measure of glacier geometry but global glacier inventories are mostly lacking length data. Only recently semi-automated approaches to measure glacier length have been developed and applied regionally. Here we present a first global assessment of glacier length using a fully automated method based on glacier surface slope, distance to the glacier margins and a set of trade-off functions. The method is developed for East Greenland, evaluated for the same area as well as for Alaska, and eventually applied to all ∼200 000 glaciers around the globe. The evaluation highlights accurately calculated glacier length where DEM quality is good (East Greenland) and limited precision on low quality DEMs (parts of Alaska). Measured length of very small glaciers is subject to a certain level of ambiguity. The global calculation shows that only about 1.5% of all glaciers are longer than 10 km with Bering Glacier (Alaska/Canada) being the longest glacier in the world at a length of 196 km. Based on model output we derive global and regional area-length scaling laws. Differences among regional scaling parameters appear to be related to characteristics of topography and glacier mass balance. The present study adds glacier length as a central parameter to global glacier inventories. Global and regional scaling laws might proof beneficial in conceptual glacier models

    Isolated photon and photon+jet production at NNLO QCD accuracy and the ratio R13/8γR_{13/8}^\gamma

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    We discuss different approaches to photon isolation in fixed-order calculations and present a new next-to-next-to-leading order (NNLO) QCD calculation of R13/8γR_{13/8}^\gamma, the ratio of the inclusive isolated photon cross section at 8 TeV and 13 TeV, differential in the photon transverse momentum, which was recently measured by the ATLAS collaboration.Comment: 4 pages, 1 figure. Contribution to the 2019 QCD session of the 54th Rencontres de Morion

    Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks 94101: evidence for aqueous alteration prior to complex mixing

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    Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks (LON) 94101 have been characterized using scanning and transmission electron microscopy and electron microprobe analysis to determine their degrees of aqueous alteration, and the timing of alteration relative to incorporation of clasts into the host. The provenance of the clasts, and the mechanism by which they were incorporated and mixed with their host material are also considered. Results show that at least five distinct types of clasts occur in LON 94101, of which four have been aqueously altered to various degrees and one is largely anhydrous. The fact that they have had different alteration histories implies that the main part of aqueous activity occurred prior to the mixing and assimilation of the clasts with their host. Further, the presence of such a variety of clasts suggests complex mixing in a dynamic environment involving material from various sources. Two of the clasts, one containing approximately 46 vol% carbonate and the other featuring crystals of pyrrhotite up to approximately 1 mm in size, are examples of unusual lithologies and indicate concentration of chemical elements in discrete areas of the parent body(ies), possibly by flow of aqueous solutions

    Sub-Zero Alteration in an Isotopically Heavy Brine Preserved in a Pristine H Chondrite Xenolith

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    Introduction: Brecciated H chondrites host a variety of xenoliths, including unshocked, phyllo- silicate-rich carbonaceous chondrites (CCs). The brecciated H chondrite Zag (H3-6) is one of two chondrites to host macroscopic (1 - 5mm), xenolithic crystals of halite (NaCl) with aqueous fluid inclusions and organics. A ~1cm CC xenolith in Zag (Zag clast) has mineralogy similar to CI chondrites, but it has a unique bulk oxygen isotopic composition among all meteorites ((exp 17)O = 1.49 0.04 , (exp 18)O = 22.38 0.17 ). The Zag clast encloses halite in its matrix, linking the coarse, matrix halite and the xenolith to the same parent object, suggested to be hydrovolcanically active. Its bulk C and N contents are the highest among chondrites and bulk (exp 15)N is similar to CR chondrites and Bells. Insoluble organic material (IOM) in the Zag clast has D and (exp 15)N hotspots, also similar to CR chondrites and Bells (C2-ung.). We provide further isotopic characterization of the Zag clast to constrain the formation temperature and origin of its primary and secondary components

    Clinical and functional characterisation of a novel TNFRSF1A c.605T > A/V173D cleavage site mutation associated with tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), cardiovascular complications and excellent response to etanercept treatment.

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    Objectives: To study the clinical outcome, treatment response, T-cell subsets and functional consequences of a novel tumour necrosis factor (TNF) receptor type 1 (TNFRSF1A) mutation affecting the receptor cleavage site. Methods: Patients with symptoms suggestive of tumour necrosis factor receptor-associated periodic syndrome (TRAPS) and 22 healthy controls (HC) were screened for mutations in the TNFRSF1A gene. Soluble TNFRSF1A and inflammatory cytokines were measured by ELISAs. TNFRSF1A shedding was examined by stimulation of peripheral blood mononuclear cells (PBMCs) with phorbol 12-myristate 13-acetate followed by flow cytometric analysis (FACS). Apoptosis of PBMCs was studied by stimulation with TNFa in the presence of cycloheximide and annexin V staining. T cell phenotypes were monitored by FACS. Results: TNFRSF1A sequencing disclosed a novel V173D/ p.Val202Asp substitution encoded by exon 6 in one family, the c.194–14G.A splice variant in another and the R92Q/p.Arg121Gln substitution in two families. Cardiovascular complications (lethal heart attack and peripheral arterial thrombosis) developed in two V173D patients. Subsequent etanercept treatment of the V173D carriers was highly effective over an 18-month follow-up period. Serum TNFRSF1A levels did not differ between TRAPS patients and HC, while TNFRSF1A cleavage from monocytes was significantly reduced in V173D and R92Q patients. TNFa-induced apoptosis of PBMCs and T-cell senescence were comparable between V173D patients and HC. Conclusions: The TNFRSF1A V173D cleavage site mutation may be associated with an increased risk for cardiovascular complications and shows a strong response to etanercept. T-cell senescence does not seem to have a pathogenetic role in affected patients

    Role-similarity based functional prediction in networked systems: Application to the yeast proteome

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    We propose a general method to predict functions of vertices where: 1. The wiring of the network is somehow related to the vertex functionality. 2. A fraction of the vertices are functionally classified. The method is influenced by role-similarity measures of social network analysis. The two versions of our prediction scheme is tested on model networks were the functions of the vertices are designed to match their network surroundings. We also apply these methods to the proteome of the yeast Saccharomyces cerevisiae and find the results compatible with more specialized methods

    The effect of aqueous alteration and metamorphism in the survival of presolar silicate grains in chondrites

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    Relatively small amounts (typically between 2-200 parts per million) of presolar grains have been preserved in the matrices of chondritic meteorites. The measured abundances of the different types of grains are highly variable from one chondrite to another, but are higher in unequilibrated chondrites that have experienced little or no aqueous alteration and/or metamorphic heating than in processed meteorites. A general overview of the abundances measured in presolar grains (particularly the recently identified presolar silicates) contained in primitive chondrites is presented. Here we will focus on the most primitive chondrite groups, as typically the highest measured abundances of presolar grains occur in primitive chondrites that have experienced little thermal metamorphism. Looking at the most aqueously altered chondrite groups, we find a clear pattern of decreasing abundance of presolar silicate grains with increasing level of aqueous alteration. We conclude that the measured abundances of presolar grains in altered chondrites are strongly biased by their peculiar histories. Scales quantifying the intensity of aqueous alteration and shock metamorphism in chondrites could correlate with the content in presolar silicates. To do this it would be required to infer the degree of destruction or homogenization of presolar grains in the matrices of primitive meteorites. To get an unbiased picture of the relative abundance of presolar grains in the different regions of the protoplanetary disk where first meteorites consolidated, future dedicated studies of primitive meteorites, IDPs, and collected materials from sample-return missions (like e.g. the planned Marco Polo) are urgently required.Comment: 15 pages, 3 figures, published in PASA as part of the Proceedings of the 2008 Torino Conference "The Origin of the Elements Heavier than Iron

    Imaging morphological details and pathological differences of red blood cells using tapping-mode AFM

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    The surface topography of red blood cells (RBCs) was investigated under nearphysiological conditions using atomic force microscopy (AFM). An immobilization protocol was established where RBCs are coupled via molecular bonds of the membrane glycoproteins to wheat germ agglutinin (WGA), which is covalently and flexibly tethered to the support. This results in a tight but noninvasive attachment of the cells. Using tappingmode AFM, which is known as gentle imaging mode and therefore most appropriate for soft biological samples like erythrocytes, it was possible to resolve membrane skeleton structures without major distortions or deformations of the cell surface. Significant differences in the morphology of RBCs from healthy humans and patients with systemic lupus erythematosus (SLE) were observed on topographical images. The surface of RBCs from SLE patients showed characteristic circularshaped holes with approx. 200 nm in diameter under physiological conditions, a possible morphological correlate to previously published changes in the SLE erythrocyte membrane

    The evaluation of liquid disinfectants to reduce Salmonella contamination on animal food manufacturing surfaces

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    Citation: Muckey, M. B., Huss, A. R., & Jones, C. K. (2016). The evaluation of liquid disinfectants to reduce Salmonella contamination on animal food manufacturing surfaces. Journal of Animal Science, 94, 79-79. doi:10.2527/msasas2016-168Recent research had demonstrated that Salmonella and Porcine Epidemic Diarrhea Virus have been isolated from feed, ingredients, and feed manufacturing equipment surfaces. However, there is limited data regarding the sanitation of animal food manufacturing surfaces. The objective of this experiment was to evaluate the effects of liquid chemical treatments to reduce Salmonella contamination of metal surfaces. Metal coupons (103cm2, stainless steel 316; Built-so-Well, Manhattan, KS) were placed in sterile Petri dish, and inoculated with 1 mL of Salmonella Typhimurium Coupons were incubated overnight at 35°C, then subjected to treatments for 15 min: 1) no inoculation or sanitation treatment (positive control), 2) inoculated with no sanitation treatment (negative control), 3) inoculated and treated with a liquid alcohol-based commercial equipment sanitizer (DrySan Duo, Ecolab, St. Paul, MN), and 4) inoculated and treated with a liquid formaldehyde-based commercial product (SalCURB; Kemin Inc., Des Moines, IA). Immediately following treatment, excess material was removed by tapping. The coupon was then swabbed and the swab vortexed in neutralizing broth (EMD Chemicals, Darmstadt, Germany) before dilution. Samples were then serial diluted (10?1 to 10?6) and spread to Trypticase Soy Agar plates. Plates were incubated at 35°C for 24 h, and then enumerated. The quantity of Salmonella colony forming units (CFU) are depicted as CFU/cm2. Data were analyzed using the GLIMMIX procedure of SAS as a completely randomized design with 3 replicates per treatment. As expected, treatment affected (P < 0.0001) residual Salmonella concentration, and there was no growth on the positive control treatment. The liquid formaldehyde-based commercial product was highly effective, resulting in no detectable growth (P < 0.05). Treating metal surfaces with the liquid alcohol-based commercial equipment sanitizer reduced (P < 0.05) Salmonella concentrations by 2 logs compared to the negative control. Liquid sanitizer treatment of metal surfaces led to a reduction in Salmonella, and can be effective steps in bacterial contamination in feed and animal food manufacturing. However, liquid sanitizers have drawbacks because they may be corrosive and most feed manufacturing equipment is not designed as clean-in-place to withstand liquid sanitation. More research is needed to evaluate dry sanitation methods that are able to break biofilms and sanitize animal food manufacturing surfaces
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