1,103 research outputs found

    Venous thromboembolism in primary nephrotic syndrome - is the risk high enough to justify prophylactic anticoagulation?

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    Background: The reported incidence of venous thromboembolism (VTE) in patients with nephrotic syndrome (NS) varies widely, as does the approach to prophylactic anticoagulation. We aimed to assess the incidence of VTE in patients with primary NS in order to inform a sample size calculation to determine if a future clinical trial will ever be feasible. Methods: All adults undergoing native renal biopsy for NS between 2008 and 2013 yielding a diagnosis of primary glomerulonephritis were identified. Baseline serum albumin, urine protein:creatinine ratio, estimated glomerular filtration rate, date of biopsy and histological diagnosis were recorded. Episodes of objectively verified VTE were identified using the electronic patient record. Sample size calculations were performed based on 2 independent samples with a dichotomous outcome and to achieve a power of 80% and p < 0.05. Results: Two hundred six patients were included of which 60% were male and mean age at biopsy was 55 years (SD 19). Median follow-up was 2.9 years (interquartile range (IQR) 1.6-4.7). Fourteen (6.8%) patients suffered VTE. Median time to diagnosis of VTE from renal biopsy was 36 days (IQR -22 to 178), with 6 VTEs occurring prior to biopsy and 1 during remission. In a total of 270 patient years of NS, there were 7 VTE that could potentially have been avoided if anticoagulation was given for the duration of NS, that is, 2.6% risk per year of NS; this risk was highest for patients with minimal change nephropathy at 13.3% per year of NS, compared to 0.65% per year of NS for those with idiopathic membranous nephropathy. Assuming a 75% reduction in the incidence of VTE with prophylactic anticoagulation, 972 participants would be required for a future clinical trial to have 80% power. Conclusions: Patients with primary NS are at an increased risk of VTE. The timing of VTE means that only half of episodes would be targeted by prophylactic anticoagulation. Given the low frequency of events, a well-powered clinical trial would be challenging to achieve

    Stable isotope signatures reveal small-scale spatial separation in populations of European sea bass

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    Scientific information about European sea bass (Dicentrarchus labrax) stocks in NE Atlantic is limited and a more accurate definition of the stock boundaries in the area is required to improve assessment and management advice. Here we study the connectivity and movement patterns of European sea bass in Wales (UK) using the stable isotope (δ13C and δ15N) composition of their scales. Analysis of fish scale δ13C and δ15N values in the last growing season was performed on 189 adult sea bass caught at nine coastal feeding grounds. Fish >50 cm total length (TL) caught in estuaries had very low δ13C and this is characteristic of fresh water (organic/soil) input, indicating the primary use of estuaries as feeding areas. A random forest classification model was used to test if there was a difference in δ15N and δ13C values between north, mid and south Wales and whether it was possible to correctly assign the fish to the area where it was caught. This analysis was restricted to fish of a similar size range (40-50 cm TL) caught in open coastal areas (n=156). The random forest classification model showed that about 75% of the fish could be correctly assigned to their collection region based on their isotope composition. The majority of the misclassifications of fish were fish from north Wales classifying to mid Wales and vice versa, while the majority of fish from south Wales were correctly assigned (80%). Our findings suggest that two sub-populations of sea bass in Welsh waters use separate feeding grounds (south vs. mid/north Wales), and may need separate management

    Adult attachment style across individuals and role-relationships: Avoidance is relationship-specific, but anxiety shows greater generalizability

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    A generalisability study examined the hypotheses that avoidant attachment, reflecting the representation of others, should be more relationship-specific (vary across relationships more than across individuals), while attachment anxiety, reflecting self-representation, should be more generalisable across a person’s relationships. College students responded to 6-item questionnaire measures of these variables for 5 relationships (mother, father, best same-gender friend, romantic partner or best opposite-gender friend, other close person), on 3 (N = 120) or 2 (N = 77) occasions separated by a few weeks. Results supported the hypotheses, with the person variance component being larger than the relationship-specific component for anxiety, and the opposite happening for avoidance. Anxiety therefore seems not to be as relationship-specific as previous research suggested. Possible reasons for discrepancies between the current and previous studies are discussed

    Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.

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    The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by the altitude and position of the area relative to the sun

    Modification of threat-processing in non-anxious individuals: a preliminary, behavioral and ERP study

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    Background and objectives: Previous research suggests that attention bias toward threat contributes to the development and maintenance of anxiety. The current study extends this work by mapping the neural correlates of experimentally-induced changes in attention bias. The study examines both behavioral and psychophysiological changes associated with experimentally-induced changes in threat bias. Methods: Thirty-four non-anxious female adults were randomly assigned to one of two conditions: training attention toward threat or placebo control. Attention bias was assessed and trained via a modified dot-probe task. Participants completed pre- and post-training assessments of attention bias and stress reactivity. As well, EEG was collected during pre- and post-test assessment of attention bias using the dot-probe task. Results: Training induced significant changes in attention bias, though findings were complicated by group differences in baseline threat-bias scores. Compared to controls, those in the training group showed greater depression vulnerability to a post-training stressor and increased P2 amplitude, an ERP component associated with attention toward threat, during the dot-probe task. Limitations: Although participants were randomly assigned to groups, there were still group differences in pre-training bias scores. Also, while the use of a stress task before the initial assessment of attention bias was used to control for initial differences in stress vulnerability, this may have altered pre-bias scores since participants completed this task immediately after being stressed. Conclusions: These findings demonstrate training-induced changes in behavior and neural response patterns relevant to work on attention bias modification

    Scientific Highlights of the HETE-2 Mission

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    The HETE-2 mission has been highly productive. It has observed more than 250 GRBs so far. It is currently localizing 25 - 30 GRBs per year, and has localized 43 GRBs to date. Twenty-one of these localizations have led to the detection of X-ray, optical, or radio afterglows, and as of now, 11 of the bursts with afterglows have known redshifts. HETE-2 has confirmed the connection between GRBs and Type Ic supernovae, a singular achievement and certainly one of the scientific highlights of the mission so far. It has provided evidence that the isotropic-equivalent energies and luminosities of GRBs are correlated with redshift, implying that GRBs and their progenitors evolve strongly with redshift. Both of these results have profound implications for the nature of GRB progenitors and for the use of GRBs as a probe of cosmology and the early universe. HETE-2 has placed severe constraints on any X-ray or optical afterglow of a short GRB. It is also solving the mystery of "optically dark' GRBs, and revealing the nature of X-ray flashes.Comment: 10 pages, 9 figures, to appear in proc. "The Restless High-Energy Universe", Royal Tropical Institute, Amsterdam; revised text, added ref

    Decomposition and nutrient release of leguminous plants in coffee agroforestry systems.

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    Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and(lignin+polyphenol)/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD), the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA), there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1). Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants

    Negatively Charged Excitons and Photoluminescence in Asymmetric Quantum Well

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    We study photoluminescence (PL) of charged excitons (XX^-) in narrow asymmetric quantum wells in high magnetic fields B. The binding of all XX^- states strongly depends on the separation δ\delta of electron and hole layers. The most sensitive is the ``bright'' singlet, whose binding energy decreases quickly with increasing δ\delta even at relatively small B. As a result, the value of B at which the singlet--triplet crossing occurs in the XX^- spectrum also depends on δ\delta and decreases from 35 T in a symmetric 10 nm GaAs well to 16 T for δ=0.5\delta=0.5 nm. Since the critical values of δ\delta at which different XX^- states unbind are surprisingly small compared to the well width, the observation of strongly bound XX^- states in an experimental PL spectrum implies virtually no layer displacement in the sample. This casts doubt on the interpretation of PL spectra of heterojunctions in terms of XX^- recombination

    Leptonic and Semileptonic Decays of Charm and Bottom Hadrons

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    We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements VcbV_{cb} and VubV_{ub}. These parameters are connected with the physics of quark flavor and mass, and they have important implications for the breakdown of CP symmetry. To extract precise values of Vcb|V_{cb}| and Vub|V_{ub}| from measurements, however, requires a good understanding of the decay dynamics. Measurements of both charm and bottom decay distributions provide information on the interactions governing these processes. The underlying weak transition in each case is relatively simple, but the strong interactions that bind the quarks into hadrons introduce complications. We also discuss new theoretical approaches, especially heavy-quark effective theory and lattice QCD, which are providing insights and predictions now being tested by experiment. An international effort at many laboratories will rapidly advance knowledge of this physics during the next decade.Comment: This review article will be published in Reviews of Modern Physics in the fall, 1995. This file contains only the abstract and the table of contents. The full 168-page document including 47 figures is available at http://charm.physics.ucsb.edu/papers/slrevtex.p
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