1,915 research outputs found

    Transport and convergence of the North Atlantic drift current computed from the average January pressure distribution

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    According to Montgomery (1936, 1938), one of the important effects of the wind blowing over the sea surface is its production of positive and negative convergence in the drift current, which is essentially limited to a surface homogeneous layer usually less than 50 meters thick. This convergence results from the net transport of the drift current at right angles to the wind, the magnitude of the transport being such that the deflecting force acting on it exactly compensates the wind stress. Of course, this involves the assumption that the drift current has come to equilibrium with the wind. To avoid boundary conditions, this theory should be applied only to the open ocean, away from coast lines and in deep water...

    Biodiversity's big wet secret: the global distribution of marine biological records reveals chronic under-exploration of the deep pelagic ocean

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    Background: Understanding the distribution of marine biodiversity is a crucial first step towards the effective and sustainable management of marine ecosystems. Recent efforts to collate location records from marine surveys enable us to assemble a global picture of recorded marine biodiversity. They also effectively highlight gaps in our knowledge of particular marine regions. In particular, the deep pelagic ocean - the largest biome on Earth - is chronically under-represented in global databases of marine biodiversity. Methodology/Principal Findings: We use data from the Ocean Biogeographic Information System to plot the position in the water column of ca 7 million records of marine species occurrences. Records from relatively shallow waters dominate this global picture of recorded marine biodiversity. In addition, standardising the number of records from regions of the ocean differing in depth reveals that regardless of ocean depth, most records come either from surface waters or the sea bed. Midwater biodiversity is drastically under-represented. Conclusions/Significance: The deep pelagic ocean is the largest habitat by volume on Earth, yet it remains biodiversity's big wet secret, as it is hugely under-represented in global databases of marine biological records. Given both its value in the provision of a range of ecosystem services, and its vulnerability to threats including overfishing and climate change, there is a pressing need to increase our knowledge of Earth's largest ecosystem

    Efficacy and Safety of Umeclidinium Added to Fluticasone Propionate/Salmeterol in Patients with COPD : Results of Two Randomized, Double-Blind Studies

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    Combinations of drugs with distinct and complementary mechanisms of action may offer improved efficacy in the treatment of chronic obstructive pulmonary disease (COPD). In two 12-week, double-blind, parallel-group studies, patients with COPD were randomized 1:1:1 to once-daily umeclidinium (UMEC; 62.5 Ī¼g and 125 Ī¼g) or placebo (PBO), added to twice-daily fluticasone propionate/salmeterol (FP/SAL; 250/50 Ī¼g). In both studies, the primary efficacy measure was trough forced expiratory volume in 1 second (FEV) at Day 85. Secondary endpoints were weighted-mean (WM) FEV over 0-6 hours post-dose (Day 84) and rescue albuterol use. Health-related quality of life outcomes (St. George's Respiratory Questionnaire [SGRQ] and COPD assessment test [CAT]) were also examined. Safety was assessed throughout. Both UMEC+FP/SAL doses provided statistically significant improvements in trough FEV (Day 85: 0.127-0.148 L) versus PBO+FP/SAL. Similarly, both UMEC+FP/SAL doses provided statistically-significant improvements in 0-6 hours post-dose WM FEV versus PBO+FP/SAL (Day 84: 0.144-0.165 L). Rescue use over Weeks 1-12 decreased with UMEC+FP/SAL in both studies versus PBO+FP/SAL (Study 1, 0.3 puffs/day [both doses]; Study 2, 0.5 puffs/day [UMEC 125+FP/SAL]). Decreases from baseline in CAT score were generally larger for both doses of UMEC+FP/SAL versus PBO+FP/SAL (except for Day 84 Study 2). In Study 1, no differences in SGRQ score were observed between UMEC+FP/SAL and PBO+FP/SAL; however, in Study 2, statistically significant improvements were observed with UMEC 62.5+FP/SAL (Day 28) and UMEC 125+FP/SAL (Days 28 and 84) versus PBO+FP/SAL. The incidence of on-treatment adverse events across all treatment groups was 37-41% in Study 1 and 36-38% in Study 2. Overall, these data indicate that the combination of UMEC+FP/SAL can provide additional benefits over FP/SAL alone in patients with COPD

    Correspondence

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    Environmental Estrogens Induce Mast Cell Degranulation and Enhance IgE-Mediated Release of Allergic Mediators

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    BACKGROUND: Prevalence and morbidity of allergic diseases have increased over the last decades. Based on the recently recognized differences in asthma prevalence between the sexes, we have examined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic pollutants have estrogen-like activities and are termed environmental estrogens. These pollutants tend to degrade slowly in the environment and to bioaccumulate and bioconcentrate in the food chain; they also have long biological half-lives. OBJECTIVES: Our goal in this study was to identify possible pathogenic roles for environmental estrogens in the development of allergic diseases. METHODS: We screened a number of environmental estrogens for their ability to modulate the release of allergic mediators from mast cells. We incubated a human mast cell line and primary mast cell cultures derived from bone marrow of wild type and estrogen receptor Ī± (ER-Ī± )ā€“deficient mice with environmental estrogens with and without estradiol or IgE and allergens. We assessed degranulation of mast cells by quantifying the release of Ī² -hexosaminidase. RESULTS: All of the environmental estrogens tested caused rapid, dose-related release of Ī² -hexosaminidase from mast cells and enhanced IgE-mediated release. The combination of physiologic concentrations of 17Ī² -estradiol and several concentrations of environmental estrogens had additive effects on mast cell degranulation. Comparison of bone marrow mast cells from ER-Ī± ā€“sufficient and ER-Ī± ā€“deficient mice indicated that much of the effect of environmental estrogens was mediated by ER-Ī± . CONCLUSIONS: Our findings suggest that estrogenic environmental pollutants might promote allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and exposure to allergens

    Metrics for Assessing Earthquake-Hazard Map Performance

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    Abstract Recent large earthquakes that caused great damage in areas predicted to be relatively safe, illustrate the importance of criteria that assess how well earthquake hazard maps used to develop codes for earthquake-resistant construction are actually performing. At present, there is no agreed-upon way of assessing how well a map performed and thus determining whether one map performed better than another. The fractional site exceedance metric implicit in current maps, that during the chosen time interval the predicted ground motion will be exceeded only at a specific fraction of the sites, is useful but permits maps to be nominally successful even if they significantly underpredict or overpredict shaking, or permits them to be nominally unsuccessful but do well in terms of predicting shaking. We explore some possible metrics that better measure the effects of overprediction and underprediction and can be weighted to reflect the two differently and to reflect differences in populations and property at risk. Although no single metric alone fully characterizes map behavior, using several metrics can provide useful insight for comparing and improving hazard maps. For example, both probabilistic and deterministic hazard maps for Italy dramatically overpredict the recorded shaking in a 2200-yr-long historical intensity catalog, illustrating problems in the data (most likely), models, or both

    Cutaneous stimulation of the digits and lips evokes responses with different adaptation patterns in primary somatosensory cortex

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    Neuromagnetic evoked fields were recorded to compare the adaptation of the primary somatosensory cortex (SI) response to tactile stimuli delivered to the glabrous skin at the fingertips of the first three digits (condition 1) and between midline upper and lower lips (condition 2). The stimulation paradigm allowed to characterize the response adaptation in the presence of functional integration of tactile stimuli from adjacent skin areas in each condition. At each stimulation site, cutaneous stimuli (50 ms duration) were delivered in three runs, using trains of 6 pulses with regular stimulus onset asynchrony (SOA). The pulses were separated by SOAs of 500 ms, 250 ms or 125 ms in each run, respectively, while the inter-train interval was fixed (5 s) across runs. The evoked activity in SI (contralateral to the stimulated hand, and bilaterally for lips stimulation) was characterized from the best-fit dipoles of the response component peaking around 70 ms for the hand stimulation, and 8 ms earlier (on average) for the lips stimulation. The SOA-dependent long-term adaptation effects were assessed from the change in the amplitude of the responses to the first stimulus in each train. The short-term adaptation was characterized by the lifetime of an exponentially saturating model function fitted to the set of suppression ratios of the second relative to the first SI response in each train. Our results indicate: 1) the presence of a rate-dependent long-term adaptation effect induced only by the tactile stimulation of the digits; and 2) shorter recovery lifetimes for the digits compared with the lips stimulation

    Phase-III, Randomized Controlled Trial of the Behavioral Intervention for Increasing Physical Activity in Multiple Sclerosis: Project BIPAMS

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    Background We propose a phase-III, randomized controlled trial (RCT) that examines the effectiveness of a behavioral intervention based on social cognitive theory (SCT) and delivered through the Internet using e-learning approaches for increasing physical activity and secondary outcomes (e.g., symptoms) in a large sample of people with multiple sclerosis (MS) residing throughout the United States. Methods/design The proposed phase-III trial will use a parallel group, RCT design that examines the effect of a 6-month behavioral intervention for increasing physical activity and secondarily improving mobility, cognition, symptoms, and quality of life (QOL) in persons with MS. The primary outcome is accelerometer-measured moderate-to-vigorous physical activity (MVPA). The secondary outcomes include self-report measures of physical activity, walking impairment, cognition, fatigue, depression, anxiety, pain, sleep quality, and QOL. The tertiary outcomes are mediator variables based on SCT. Participants (Nā€Æ=ā€Æ280) will be randomized into behavioral intervention (nā€Æ=ā€Æ140) or attention and social contact control (nā€Æ=ā€Æ140) conditions using computerized random numbers with concealed allocation. The conditions will be administered over 6-months by persons who are uninvolved in screening, recruitment, random assignment, and outcome assessment. There will be a 6-month follow-up without intervention access/content. We will collect primary, secondary, and tertiary outcome data every 6ā€Æmonths over the 12-month period. Data analysis will involve intent-to-treat principles and latent growth modeling (LGM). Discussion The proposed research will provide evidence for the effectiveness of a novel, widely scalable approach for increasing lifestyle physical activity and improving secondary outcomes and QOL in persons with MS

    Influence of Nanoparticle Size and Shape on Oligomer Formation of an Amyloidogenic Peptide

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    Understanding the influence of macromolecular crowding and nanoparticles on the formation of in-register Ī²\beta-sheets, the primary structural component of amyloid fibrils, is a first step towards describing \emph{in vivo} protein aggregation and interactions between synthetic materials and proteins. Using all atom molecular simulations in implicit solvent we illustrate the effects of nanoparticle size, shape, and volume fraction on oligomer formation of an amyloidogenic peptide from the transthyretin protein. Surprisingly, we find that inert spherical crowding particles destabilize in-register Ī²\beta-sheets formed by dimers while stabilizing Ī²\beta-sheets comprised of trimers and tetramers. As the radius of the nanoparticle increases crowding effects decrease, implying smaller crowding particles have the largest influence on the earliest amyloid species. We explain these results using a theory based on the depletion effect. Finally, we show that spherocylindrical crowders destabilize the ordered Ī²\beta-sheet dimer to a greater extent than spherical crowders, which underscores the influence of nanoparticle shape on protein aggregation
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