5,177 research outputs found

    Lifetimes of antiferromagnetic magnons in two and three dimensions: experiment, theory, and numerics

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    A high-resolution neutron spectroscopic technique is used to measure momentum-resolved magnon lifetimes in the prototypical two- and three-dimensional antiferromagnets Rb2MnF4 and MnF2, over the full Brillouin zone and a wide range of temperatures. We rederived theories of the lifetime resulting from magnon-magnon scattering, thereby broadening their applicability beyond asymptotically small regions of wavevector and temperature. Corresponding computations, combined with a small contribution reflecting collisions with domain boundaries, yield excellent quantitative agreement with the data.Comment: 5 pages, 4 figure

    Discovery of mating in the major African livestock pathogen Trypanosoma congolense

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    The protozoan parasite, Trypanosoma congolense, is one of the most economically important pathogens of livestock in Africa and, through its impact on cattle health and productivity, has a significant effect on human health and well being. Despite the importance of this parasite our knowledge of some of the fundamental biological processes is limited. For example, it is unknown whether mating takes place. In this paper we have taken a population genetics based approach to address this question. The availability of genome sequence of the parasite allowed us to identify polymorphic microsatellite markers, which were used to genotype T. congolense isolates from livestock in a discrete geographical area of The Gambia. The data showed a high level of diversity with a large number of distinct genotypes, but a deficit in heterozygotes. Further analysis identified cryptic genetic subdivision into four sub-populations. In one of these, parasite genotypic diversity could only be explained by the occurrence of frequent mating in T. congolense. These data are completely inconsistent with previous suggestions that the parasite expands asexually in the absence of mating. The discovery of mating in this species of trypanosome has significant consequences for the spread of critical traits, such as drug resistance, as well as for fundamental aspects of the biology and epidemiology of this neglected but economically important pathogen

    Consistent Reduction in Periprocedural Myocardial Infarction With Cangrelor as Assessed by Multiple Definitions

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    BACKGROUND: Cangrelor is an intravenous P2Y12 inhibitor approved to reduce periprocedural ischemic events in patients undergoing percutaneous coronary intervention not pretreated with a P2Y12 inhibitor. METHODS: A total of 11 145 patients were randomized to cangrelor or clopidogrel in the CHAMPION PHOENIX trial (Cangrelor versus Standard Therapy to Achieve Optimal Management of Platelet Inhibition). We explored the effects of cangrelor on myocardial infarction (MI) using different definitions and performed sensitivity analyses on the primary end point of the trial. RESULTS: A total of 462 patients (4.2%) undergoing percutaneous coronary intervention had an MI as defined by the second universal definition. The majority of these MIs (n=433, 93.7%) were type 4a. Treatment with cangrelor reduced the incidence of MI at 48 hours (3.8% versus 4.7%; odds ratio [OR], 0.80; 95% confidence interval [CI], 0.67-0.97; P=0.02). When the Society of Coronary Angiography and Intervention definition of periprocedural MI was applied to potential ischemic events, there were fewer total MIs (n=134); however, the effects of cangrelor on MI remained significant (OR, 0.65; 95% CI, 0.46-0.92; P=0.01). Similar effects were seen in the evaluation of the effects of cangrelor on MIs with peak creatinine kinase-MB ≥10 times the upper limit of normal (OR, 0.64; 95% CI, 0.45-0.91) and those with peak creatinine kinase-MB ≥10 times the upper limit of normal, ischemic symptoms, or ECG changes (OR, 0.63; 95% CI, 0.48-0.84). MIs defined by any of these definitions were associated with increased risk of death at 30 days. Treatment with cangrelor reduced the composite end point of death, MI (Society of Coronary Angiography and Intervention definition), ischemia-driven revascularization, or Academic Research Consortium definite stent thrombosis (1.4% versus 2.1%; OR, 0.69; 95% CI, 0.51-0.92). CONCLUSIONS: MI in patients undergoing percutaneous coronary intervention, regardless of definition, remains associated with increased risk of death in the current era. Cangrelor compared with clopidogrel significantly reduces MI regardless of the definition. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT01156571

    Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

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    Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship

    Efficacy and safety of cangrelor in patients with peripheral artery disease undergoing percutaneous coronary intervention – Insights from the CHAMPION program

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    Abstract Background Peripheral artery disease (PAD) is associated with an increased risk of ischemic events following percutaneous coronary intervention (PCI). More aggressive antiplatelet therapy may mitigate this risk. The present study evaluates the efficacy of cangrelor in patients with PAD undergoing PCI. Methods and results This is a pooled analysis from the CHAMPION PCI, CHAMPION PLATFORM, AND CHAMPION PHOENIX trials, evaluating cangrelor versus either clopidogrel or placebo in PCI patients. The occurrence of the primary endpoint of death, myocardial infarction, or ischemia-driven revascularization (IDR) was assessed in patients with and without PAD. GUSTO severe bleeding at 48 h was also evaluated. There were 1720 (7%) patients with PAD and 22,802 (93%) without PAD. After adjustment for differences in baseline variables, PAD patients, compared with those without PAD, experienced increased odds of the primary endpoint (OR [95% CI] = 1.27 [0.91, 1.77], P = 0.16) and GUSTO severe bleeding (OR [95% CI] = 3.24 [1.28, 8.21], P = 0.01). In PAD patients, the primary endpoint was 4.7% with cangrelor vs. 7.2% with clopidogrel (OR [95% CI] = 0.64 [0.42,0.96]); in patients without PAD the primary endpoint was 3.5% with cangrelor vs. 4.2% with clopidogrel (OR [95% CI] = 0.83 [0.72,0.95]), P-interaction 0.23. Among patients with or without PAD, there was no significant difference in the rate of GUSTO severe bleeding with cangrelor compared with control, P-interaction 0.86. Conclusions In a pooled analysis of the CHAMPION studies, PAD was associated with increased rates of ischemic and bleeding complications. Cangrelor reduced the odds of ischemic events, without increasing GUSTO severe bleeding. Clinical trial registration clinicaltrials.gov identifiers: CHAMPION PCI ( NCT00305162 ), CHAMPION PLATFORM ( NCT00385138 ), CHAMPION PHOENIX ( NCT01156571

    A DIGE study on the effects of salbutamol on the rat muscle proteome - an exemplar of best practice for data sharing in proteomics

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    BACKGROUND: Proteomic techniques allow researchers to perform detailed analyses of cellular states and many studies are published each year, which highlight large numbers of proteins quantified in different samples. However, currently few data sets make it into public databases with sufficient metadata to allow other groups to verify findings, perform data mining or integrate different data sets. The Proteomics Standards Initiative has released a series of "Minimum Information About a Proteomics Experiment" guideline documents (MIAPE modules) and accompanying data exchange formats. This article focuses on proteomic studies based on gel electrophoresis and demonstrates how the corresponding MIAPE modules can be fulfilled and data deposited in public databases, using a new experimental data set as an example. FINDINGS: We have performed a study of the effects of an anabolic agent (salbutamol) at two different time points on the protein complement of rat skeletal muscle cells, quantified by difference gel electrophoresis. In the DIGE study, a total of 31 non-redundant proteins were identified as being potentially modulated at 24 h post treatment and 110 non redundant proteins at 96 h post-treatment. Several categories of function have been highlighted as strongly enriched, providing candidate proteins for further study. We also use the study as an example of best practice for data deposition. CONCLUSIONS: We have deposited all data sets from this study in public databases for further analysis by the community. We also describe more generally how gel-based protein identification data sets can now be deposited in the PRoteomics IDEntifications database (PRIDE), using a new software tool, the PRIDESpotMapper, which we developed to work in conjunction with the PRIDE Converter application. We also demonstrate how the ProteoRed MIAPE generator tool can be used to create and share a complete and compliant set of MIAPE reports for this experiment and others

    Digital Platforms in the Global South: Foundations and Research Agenda

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    Digital platforms have become integral to many of the everyday activities that people across the globe encounter in areas like transportation, commerce and social interactions. Research on the topic has largely concentrated on the general functioning of these platforms in terms of platform governance, business strategies and consumer behaviour. Despite their significant presence in the global South, the developmental implications of digital platforms remain largely understudied. In part, this is because digital platforms are a challenging research object due to their lack of conceptual definition, their spread across different regions and industries, and their intertwined nature with institutions, actors and digital technologies. The aim of this paper is therefore twofold: to provide a conceptual definition of digital platforms, and to identify research strands in international development contexts. To do so, we draw from digital platforms literature, differentiate between transaction and innovation platforms and expose their main characteristics. We the present four strands in the form of research questions, illustrated with concrete examples, that can assist to pursue relevant studies on digital platforms and international development in the future
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