1,520 research outputs found

    Dynamics of Rye Chromosome 1R Regions with High or Low Crossover Frequency in Homology Search and Synapsis Development

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    In many organisms, homologous pairing and synapsis depend on the meiotic recombination machinery that repairs double-strand DNA breaks (DSBs) produced at the onset of meiosis. The culmination of recombination via crossover gives rise to chiasmata, which locate distally in many plant species such as rye, Secale cereale. Although, synapsis initiates close to the chromosome ends, a direct effect of regions with high crossover frequency on partner identification and synapsis initiation has not been demonstrated. Here, we analyze the dynamics of distal and proximal regions of a rye chromosome introgressed into wheat to define their role on meiotic homology search and synapsis. We have used lines with a pair of two-armed chromosome 1R of rye, or a pair of telocentrics of its long arm (1RL), which were homozygous for the standard 1RL structure, homozygous for an inversion of 1RL that changes chiasma location from distal to proximal, or heterozygous for the inversion. Physical mapping of recombination produced in the ditelocentric heterozygote (1RL/1RLinv) showed that 70% of crossovers in the arm were confined to a terminal segment representing 10% of the 1RL length. The dynamics of the arms 1RL and 1RLinv during zygotene demonstrates that crossover-rich regions are more active in recognizing the homologous partner and developing synapsis than crossover-poor regions. When the crossover-rich regions are positioned in the vicinity of chromosome ends, their association is facilitated by telomere clustering; when they are positioned centrally in one of the two-armed chromosomes and distally in the homolog, their association is probably derived from chromosome elongation. On the other hand, chromosome movements that disassemble the bouquet may facilitate chromosome pairing correction by dissolution of improper chromosome associations. Taken together, these data support that repair of DSBs via crossover is essential in both the search of the homologous partner and consolidation of homologous synapsis

    Bt Crop Effects on Functional Guilds of Non-Target Arthropods: A Meta-Analysis

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    Background: Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt). We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of Bt cotton, maize and potato on the abundance and interactions of arthropod non-target functional guilds. Methodology/Principal Findings: We compared the abundance of predators, parasitoids, omnivores, detritivores and herbivores under scenarios in which neither, only the non-Bt crops, or both Bt and non-Bt crops received insecticide treatments. Predators were less abundant in Bt cotton compared to unsprayed non-Bt controls. As expected, fewer specialist parasitoids of the target pest occurred in Bt maize fields compared to unsprayed non-Bt controls, but no significant reduction was detected for other parasitoids. Numbers of predators and herbivores were higher in Bt crops compared to sprayed non-Bt controls, and type of insecticide influenced the magnitude of the difference. Omnivores and detritivores were more abundant in insecticide-treated controls and for the latter guild this was associated with reductions of their predators in sprayed non-Bt maize. No differences in abundance were found when both Bt and non-Bt crops were sprayed. Predator-to-prey ratios were unchanged by either Bt crops or the use of insecticides; ratios were higher in Bt maize relative to the sprayed non-Bt control

    Effect of medication review and cognitive behaviour treatment by community pharmacists of patients discharged from the hospital on drug related problems and compliance: design of a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Drug related problems (DRPs) are common among elderly patients who are discharged from the hospital and are using several drugs for their chronic diseases. Examples of drug related problems are contra-indications, interactions, adverse drug reactions and inefficacy of treatment. Causes of these problems include prescription errors and non-compliance with treatment. The aim of this study is to examine the effect of <it>medication review </it>and <it>cognitive behaviour therapy </it>of discharged patients by community pharmacists to minimize the occurrence of drug related problems.</p> <p>Methods/Design</p> <p>A randomized controlled trial will be performed. Community pharmacists will be randomized into a control group and an intervention group. 342 Patients, aged over 60 years, discharged from general and academic hospitals, using five or more prescription drugs for their chronic disease will be asked by their pharmacy to participate in the study.</p> <p>Patients randomized to the control group will receive usual care according to the Dutch Pharmacy Standard. The medication of patients randomised to the intervention group will be reviewed by the community pharmacist with use of the national guidelines for the treatment of diseases, when patients are discharged from the hospital. The Pharmaceutical Care network Europe Registration form will be used to record drug related problems. Trained pharmacy technicians will counsel patients at home at baseline and at 1,3,6,9 and 12 months, using Cognitive Behaviour Treatment according to the Theory of Planned Behaviour. The patient's attitude towards medication and patient's adherence will be subject of the cognitive behaviour treatment. The counselling methods that will be used are <it>motivational interviewing </it>and <it>problem solving treatment</it>. Patients adherence towards drug use will be determined with use of the Medication Adherence Report Scale Questionnaire. There will be a follow-up of 12 months.</p> <p>The two primary outcome measures are the difference in occurrence of DRPs between intervention and control group and adherence with drug use. Secondary endpoints are attitude towards drug use, incidence of Re-hospitalisations related to medicines, functional status of the patient, quality of life and the cost-effectiveness of this intervention.</p> <p>Discussion</p> <p>Combining both medication review and Cognitive Behaviour Treatment may decrease DRPs and may result in more compliance with drug use among patients discharged from the hospital and using 5 or more chronic drugs.</p> <p>Trial registration</p> <p>Dutch Trial Register NTR1194</p

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

    A strategy to obtain axenic cultures of Arthrospira spp. cyanobacteria

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    A strategy to obtain axenic cultures of the cyanobacterium Arthrospira sp. (‘platensis’) Lefevre 1963/M-132-1 strain, consisting of a series of physical and chemical procedures, and the application of an optimized pool of antibiotics, is described in this paper. This strategy, which is an inexpensive and fast way to obtain axenic cultures, can be applied to Arthrospira spp. from culture collections or samples from their natural habitats to eliminate a wide spectrum of contaminants. A high alkaline treatment (pH 12, using KOH) of 72 h is a determinant initial procedure applied to eliminate protozoa and Microcystis sp. Bacteria were eliminated by an optimal antibiotic pool treatment, and Chroococcus sp. residuals were discarded by serial dilution. Optimal concentrations of the antibiotics composing the pool were obtained by a 24 factorial central composite rotatable design (CCRD) and Response Surface Methodology (RSM), resulting in: ampicillin 61.6 μg/ml, penicillin 85.8 μg/ml, cefoxitin 76.9 μg/ml, and meropenem 38.9 μg/ml. The results also indicate that cefoxitin was the most effective antibiotic of this pool. After obtaining the axenic culture, identification of Lefevre 1963/M-132-1 strain was performed using amplification and sequencing of the ITS region (including part of 16S rRNA, tRNA Ile, ITS, tRNA Ala and part of 23S rRNA region) and fatty acid composition data. Data base comparison revealed that Lefevre strain is closely related to A. platensis species (99% identity), while fatty acid composition data suggested A. maxima. These seemingly contradictory results are discussed

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Compressed representation of a partially defined integer function over multiple arguments

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    In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one
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