130 research outputs found

    Fluid-membrane tethers: minimal surfaces and elastic boundary layers

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    Thin cylindrical tethers are common lipid bilayer membrane structures, arising in situations ranging from micromanipulation experiments on artificial vesicles to the dynamic structure of the Golgi apparatus. We study the shape and formation of a tether in terms of the classical soap-film problem, which is applied to the case of a membrane disk under tension subject to a point force. A tether forms from the elastic boundary layer near the point of application of the force, for sufficiently large displacement. Analytic results for various aspects of the membrane shape are given.Comment: 12 page

    Western Spruce Budworm and Wildfire: Is There a Connection?

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    In the interior Pacific Northwest, extensive defoliation of mixed conifer forests during outbreaks of western spruce budworm (WSB) may leave the visual impression of a tinderbox with trees primed to burst into flame. But is this the case? We addressed this question with funding from the USDA/U.S. Department of the Interior Joint Fire Science Program (project 09– 1–06–5). Here we summarize our three recent publications exploring the potential relationship between WSB outbreaks and fire. We used a multimethod approach to explore potential disturbance interactions that might cause one disturbance to change the occurrence or severity of the other. We used tree-ring records to see whether WSB and fire are related in time and computer modeling to see how defoliation could affect crown fire behavior

    Haloes gone MAD: The Halo-Finder Comparison Project

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    [abridged] We present a detailed comparison of fundamental dark matter halo properties retrieved by a substantial number of different halo finders. These codes span a wide range of techniques including friends-of-friends (FOF), spherical-overdensity (SO) and phase-space based algorithms. We further introduce a robust (and publicly available) suite of test scenarios that allows halo finder developers to compare the performance of their codes against those presented here. This set includes mock haloes containing various levels and distributions of substructure at a range of resolutions as well as a cosmological simulation of the large-scale structure of the universe. All the halo finding codes tested could successfully recover the spatial location of our mock haloes. They further returned lists of particles (potentially) belonging to the object that led to coinciding values for the maximum of the circular velocity profile and the radius where it is reached. All the finders based in configuration space struggled to recover substructure that was located close to the centre of the host halo and the radial dependence of the mass recovered varies from finder to finder. Those finders based in phase space could resolve central substructure although they found difficulties in accurately recovering its properties. Via a resolution study we found that most of the finders could not reliably recover substructure containing fewer than 30-40 particles. However, also here the phase space finders excelled by resolving substructure down to 10-20 particles. By comparing the halo finders using a high resolution cosmological volume we found that they agree remarkably well on fundamental properties of astrophysical significance (e.g. mass, position, velocity, and peak of the rotation curve).Comment: 27 interesting pages, 20 beautiful figures, and 4 informative tables accepted for publication in MNRAS. The high-resolution version of the paper as well as all the test cases and analysis can be found at the web site http://popia.ft.uam.es/HaloesGoingMA

    Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

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    A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site 1C analysis (U.S. Geological Survey mobile lab) and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern) and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan). Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad™ AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns

    Identification of oncofetal PIWI-interacting RNAs as potential prognostic biomarkers in non-small cell lung cancer

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    Lung cancer is the leading cause of cancer-related deaths worldwide, with non-small cell lung cancer (NSCLC) accounting for the majority of these cases. Despite advancements in targeted therapies, early detection remains a significant challenge, highlighting the need for novel biomarkers. This study investigates the role of PIWI-interacting RNAs (piRNAs) in lung cancer, specifically focusing on their potential as oncofetal biomarkers in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), the two most common histological subtypes of NSCLC. We hypothesize that piRNAs exhibit oncofetal expression patterns and may contribute to lung cancer development. Through bioinformatics analysis, we identified distinct piRNA profiles in non-neoplastic, malignant, and fetal lung tissues. Among these, 37 piRNAs in LUAD and 46 piRNAs in LUSC displayed oncofetal expression, meaning they were present in tumor tissues but absent in adjacent normal lung tissue. These oncofetal piRNAs showed significant prognostic value in both LUAD and LUSC cohorts, with a specific signature of eight oncofetal piRNAs predicting high-risk patients in LUAD. We validated the robustness of this signature in a separate in-house cohort, which underscores its potential as a prognostic biomarker. Our findings suggest that oncofetal piRNAs could offer new diagnostic and therapeutic opportunities, particularly for early detection

    NT-proBNP for Risk Prediction in Heart Failure:Identification of Optimal Cutoffs Across Body Mass Index Categories

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    OBJECTIVES The goal of this study was to assess the predictive power of N-terminal pro–B-type natriuretic peptide (NT-proBNP) and the decision cutoffs in heart failure (HF) across body mass index (BMI) categories. BACKGROUND  Concentrations of NT-proBNP predict outcome in HF. Although the influence of BMI to reduce levels of NT-proBNP is known, the impact of obesity on prognostic value remains uncertain. METHODS Individual data from the BIOS (Biomarkers In Heart Failure Outpatient Study) consortium were analyzed. Patients with stable HF were classified as underweight (BMI = 40 kg/m(2)) obese. The prognostic rote of NT-proBNP was tested for the endpoints of all-cause and cardiac death. RESULTS The study population included 12,763 patients (mean age 66 +/- 12 years; 25% women; mean left ventricular ejection fraction 33% 113%). Most patients were overweight (n = 5,176), followed by normal weight (n = 4,299), mildly obese (n = 2,157), moderately obese (n = 612), severely obese (n = 314), and underweight (n = 205). NT-proBNP inversely correlated with BMI (beta = -0.174 for 1 kg/m(2); P < 0.001). Adding NT-proBNP to clinical models improved risk prediction across BMI categories, with the exception of severely obese patients. The best cutoffs of NT-proBNP for 5-year all-cause death prediction were lower as BMI increased (3,785 ng/L, 2,193 ng/L, 1,554 ng/L, 1,045 ng/L, 755 ng/L, and 879 ng/L, for underweight, normal weight, overweight, and mildly, moderately, and severely obese patients, respectively) and were higher in women than in men. CONCLUSIONS NT-proBNP maintains its independent prognostic value up to 40 kg/m(2) BMI, and tower optimal risk-prediction cutoffs are observed in overweight and obese patients

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Colonial Archives and the Arts of Governance

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    Anthropologists engaged inpost-colonial studies are increasingly adoptingan historical perspective and using archives. Yet their archival activity tends to remain morean extractive than an ethnographic one.Documents are thus still invokedpiecemeal to confirm the colonial invention ofcertain practices or to underscore culturalclaims, silent. Yet such mining of the content of government commissions,reports, and other archival sources rarely paysattention to their peculiar placement and form .Scholars need to move fromarchive-as-source to archive-as-subject. Thisarticle, using document production in the DutchEast Indies as an illustration, argues thatscholars should view archives not as sites ofknowledge retrieval, but of knowledgeproduction, as monuments of states as well assites of state ethnography. This requires asustained engagement with archives as culturalagents of ``fact'' production, of taxonomies inthe making, and of state authority. What constitutes thearchive, what form it takes, and what systemsof classification and epistemology signal atspecific times are (and reflect) critical featuresof colonial politics and state power. The archive was the supreme technology of thelate nineteenth-century imperial state, arepository of codified beliefs that clustered(and bore witness to) connections betweensecrecy, the law, and power.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41825/1/10502_2004_Article_5096461.pd

    Etnografia e aprendizagem na prática: explorando caminhos a partir do futebol no Brasil

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    Resumo O artigo propõe apresentar reflexões e questões construídas na condução de pesquisas a respeito do tema da aprendizagem em contextos de práticas sociais diversificadas. A orientação comum que permitiu o confronto entre os diferentes trabalhos e contextos empíricos foi construída a partir da abordagem da aprendizagem situada de Jean Lave (1991, 2011), em diálogo com autores como Gregory Bateson (1972) e Tim Ingold (2000). Os contextos investigados caracterizam-se pela singularidade em relação a temas próprios da sociedade brasileira, tais como o futebol, as religiões afro-brasileiras, práticas tradicionais indígenas, dentre outras. Em todas as investigações, o eixo condutor foi a prática em suas diversas configurações – o que quase sempre inclui a escola, que é, no entanto, ressituada a partir do ponto de vista da prática focalizada na investigação. Alguns aspectos recorrentes indicaram a possibilidade de se pensar na aprendizagem da cultura como tema de pesquisa que atravessa fronteiras disciplinares e que permite revelar facetas inusitadas de práticas que marcam a paisagem do Brasil contemporâneo. Como recorte, o artigo discute as reflexões de caráter conceitual-metodológico que as investigações permitiram realizar a partir de um duplo movimento: focalizando aspectos relevantes que emergiram nas investigações (sobretudo a partir do caso emblemático do futebol, cuja aprendizagem é amplamente difundida no Brasil); e produzindo reflexões acerca da prática etnográfica, ao recolocar a etnografia como fundamento para a realização de tal empreitada
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