527 research outputs found
COBRA: a new European research project for organic plant breeding
Development of organic plant breeding and seed production will have a valuable impact on organic plant production. Breeding of plant material adapted for organic agriculture is crucial in order to cope with stresses such as climate change, weeds and seed borne diseases. Conventional varieties may not meet the specific needs of organic agriculture. The use of plant material adapted to conditions of organic agriculture will have a positive effect on the productivity and sustainability of organic crop production
Vortex reflection at boundaries of Josephson-junction arrays
We study the propagation properties of a single vortex in square
Josephson-junction arrays (JJA) with free boundaries and subject to an applied
dc current. We model the dynamics of the JJA by the resistively and
capacitively shunted junction (RCSJ) equations. For zero Stewart-McCumber
parameter we find that the vortex always escapes from the array when
it gets to the boundary. For and for low currents we find
that the vortex escapes, while for larger currents the vortex is reflected as
an antivortex at one edge and the antivortex as a vortex at the other, leading
to a stationary oscillatory state and to a non-zero time-averaged voltage. The
escape and the reflection of a vortex at the array edges are qualitatively
explained in terms of a coarse-grained model of a vortex interacting
logarithmically with its image. We also discuss the case when the free
boundaries are at degrees with respect to the direction of the vortex
motion. Finally, we discuss the effect of self-induced magnetic fields by
taking into account the full-range inductance matrix of the array, and find
qualitatively equivalent results.Comment: 14 pages RevTex, 9 Postscript figure
A theoretical framework and research agenda for studying team attributions in sport
The attributions made for group outcomes have attracted a great deal of interest in recent years. In this article we bring together much of the current research on attribution theory in sport and outline a new conceptual framework and research agenda for investigating the attributions of team members. The proposed framework draws on multiple conceptual approaches including models of attribution, group dynamics and stress responses to provide a detailed hypothetical description of athletes' physiological, cognitive and affective responses to group competition. In describing this model we outline important antecedents of team attributions before hypothesising how attributions can impact hormonal and cardiovascular responses of athletes, together with cognitive (goals, choices, expectations), affective (self-esteem, emotions), and behavioural (approach-avoidance actions) responses of groups and group members. We conclude by outlining important methodological considerations and implications for structured context specific attribution-based interventions
Nanocrystal and surface alloy properties of bimetallic Gold-Platinum nanoparticles
We report on the correlation between the nanocrystal and surface alloy properties with the bimetallic composition of gold-platinum(AuPt) nanoparticles. The fundamental understanding of whether the AuPt nanocrystal core is alloyed or phase-segregated and how the surface binding properties are correlated with the nanoscale bimetallic properties is important not only for the exploitation of catalytic activity of the nanoscale bimetallic catalysts, but also to the general exploration of the surface or interfacial reactivities of bimetallic or multimetallic nanoparticles. The AuPt nanoparticles are shown to exhibit not only single-phase alloy character in the nanocrystal, but also bimetallic alloy property on the surface. The nanocrystal and surface alloy properties are directly correlated with the bimetallic composition. The FTIR probing of CO adsorption on the bimetallic nanoparticles supported on silica reveals that the surface binding sites are dependent on the bimetallic composition. The analysis of this dependence further led to the conclusion that the relative Au-atop and Pt-atop sites for the linear CO adsorption on the nanoparticle surface are not only correlated with the bimetallic composition, but also with the electronic effect as a result of the d-band shift of Pt in the bimetallic nanocrystals, which is the first demonstration of the nanoscale core-surface property correlation for the bimetallic nanoparticles over a wide range of bimetallic composition
A Conformally Invariant Holographic Two-Point Function on the Berger Sphere
We apply our previous work on Green's functions for the four-dimensional
quaternionic Taub-NUT manifold to obtain a scalar two-point function on the
homogeneously squashed three-sphere (otherwise known as the Berger sphere),
which lies at its conformal infinity. Using basic notions from conformal
geometry and the theory of boundary value problems, in particular the
Dirichlet-to-Robin operator, we establish that our two-point correlation
function is conformally invariant and corresponds to a boundary operator of
conformal dimension one. It is plausible that the methods we use could have
more general applications in an AdS/CFT context.Comment: 1+49 pages, no figures. v2: Several typos correcte
Cost-effectiveness of Evolocumab therapy for reducing cardiovascular events in patients with atherosclerotic cardiovascular disease
Importance: The proprotein convertase subtilisin/kexin type 9 inhibitor evolocumab has been demonstrated to reduce the composite of myocardial infarction, stroke, or cardiovascular death in patients with established atherosclerotic cardiovascular disease. To our knowledge, long-term cost-effectiveness of this therapy has not been evaluated using clinical trial efficacy data. Objective: To evaluate the cost-effectiveness of evolocumab in patients with atherosclerotic cardiovascular disease when added to standard background therapy. Design, Setting, and Participants: A Markov cohort state-transition model was used, integrating US population-specific demographics, risk factors, background therapy, and event rates along with trial-based event risk reduction. Costs, including price of drug, utilities, and transitional probabilities, were included from published sources. Exposures: Addition of evolocumab to standard background therapy including statins. Main Outcomes and Measures: Cardiovascular events including myocardial infarction, ischemic stroke and cardiovascular death, quality-adjusted life-year (QALY), incremental cost-effectiveness ratio (ICER), and net value-based price. Results: In the base case, using US clinical practice patients with atherosclerotic cardiovascular disease with low-density lipoprotein cholesterol levels of at least 70 mg/dL (to convert to millimoles per liter, multiply by 0.0259) and an annual events rate of 6.4 per 100 patient-years, evolocumab was associated with increased cost and improved QALY: incremental cost, 268 637 per QALY gained (10 311 based on mean rebate of 29% for branded pharmaceuticals). Sensitivity and scenario analyses demonstrated ICERs ranging from 488 642 per QALY, with ICER of 270 192 with discounted price of 483 800 if no cardiovascular mortality reduction emerges. Evolocumab treatment exceeded 9669 (10 311 in patients with low-density lipoprotein cholesterol levels of at least 80 mg/dL. Conclusions and Relevance: At its current list price of 150 000 per QALY, the annual net price would need to be substantially lower (6780 for trial participants), or a higher-risk population would need to be treated
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