2,883 research outputs found
Physical Baryon Resonance Spectroscopy from Lattice QCD
We complement recent advances in the calculation of the masses of excited
baryons in quenched lattice QCD with finite-range regulated chiral effective
field theory enabling contact with the physical quark mass region. We examine
the P-wave contributions to the low-lying nucleon and delta resonances.Comment: Contributed paper at FB17, the 17th International Conference on
Few-Body Problems in Physics, Durham, NC, June 5-10, 2003. 3 pages, 6 figure
Validating Forward Modeling and Inversions of Helioseismic Holography Measurements
Here we use synthetic data to explore the performance of forward models and
inverse methods for helioseismic holography. Specifically, this work presents
the first comprehensive test of inverse modeling for flows using
lateral-vantage (deep-focus) holography. We derive sensitivity functions in the
Born approximation. We then use these sensitivity functions in a series of
forward models and inversions of flows from a publicly available
magnetohydrodynamic quiet-Sun simulation. The forward travel times computed
using the kernels generally compare favorably with measurements obtained by
applying holography, in a lateral-vantage configuration, on a 15-hour time
series of artificial Dopplergrams extracted from the simulation. Inversions for
the horizontal flow components are able to reproduce the flows in the upper 3Mm
of the domain, but are compromised by noise at greater depths.Comment: accepted for publication by the Astrophysical
Riding against the wind: a review of competition cycling aerodynamics
Aerodynamics has such a profound impact on cycling performance at the elite level that it has infiltrated almost every aspect of the sport from riding position and styles, equipment design and selection, race tactics and training regimes, governing rules and regulations to even the design of new velodromes. This paper presents a review of the aspects of aerodynamics that are critical to understanding flows around cyclists under racing conditions, and the methods used to evaluate and improve aerodynamic performance at the elite level. The fundamental flow physics of bluff body aerodynamics and the mechanisms by which the aerodynamic forces are imparted on cyclists are described. Both experimental and numerical techniques used to investigate cycling aerodynamic performance and the constraints on implementing aerodynamic saving measures at the elite level are also discussed. The review reveals that the nature of cycling flow fields are complex and multi-faceted as a result of the highly three-dimensional and variable geometry of the human form, the unsteady racing environment flow field, and the non-linear interactions that are inherent to all cycling flows. Current findings in this field have and will continue to evolve the sport of elite cycling while also posing a multitude of potentially fruitful areas of research for further gains in cycling performance
LaF3 insulators for MIS structures
Thin films of Laf3 deposited on Si or GaAs substrates have been observed to form blocking contacts with very high capacitances. This results in comparativelyâhysteresisâfree and sharpCâV (capacitanceâvoltage) characteristics for MIS structures. Such structures have been used to study the interface states of GaAs with increased resolution and to construct improved photocapacitive infrared detectors
Vegetation and Arthropod Responses to Brush Reduction by Grubbing and Stacking
Grubbing is a mechanical brush-reduction technique that allows targeting of mesquite (Prosopis glandulosa) and huisache (Vachellia farnesiana) and can be used to open lanes for hunting northern bobwhites (Colinus virginianus). Follow-up treatments of stacking allow the piling up of downed brush. We initiated this study on the Santa Gertrudis Division of the King Ranch, Inc., Texas, to determine effects of grubbing and stacking on vegetation and arthropod communities important to bobwhite. We hypothesized that grubbing and stacking would be able to selectively remove mesquite and huisache while leaving mixed brush species largely intact. We hypothesized that soil disturbance treatments would lead to improved brooding, feeding, and nesting habitat for bobwhite through an increase in herbaceous food plants, arthropods, and nesting cover. We sampled vegetation prior to treatment during July 2012 and posttreatment during November 2012, March 2013, and July 2013. We sampled arthropods before treatment in July 2012 and monthly posttreatment until July 2013, a year marked by extreme drought in South Texas. We detected a positive response of bobwhite food grasses and/or sedges 1 year after initial treatments but detected no treatment effect on bobwhite food forbs. We detected no effects of treatments on nesting cover. Grubbing and stacking did not affect total Insecta abundance; however, Insecta biomass and Arachnida abundance and biomass responded both positively and negatively to treatments. To better understand the effects of grubbing and stacking, replication of this study during years of average and above average precipitation should be conducted
The New Political Economy of EU State Aid Policy
Despite its importance and singularity, the EUâs state aid policy has attracted less scholarly attention than other elements of EU competition policy. Introducing the themes addressed by the special issue, this article briefly reviews the development of EU policy and highlights why the control of state aid matters. The Commissionâs response to the current economic crisis notably in banking and the car industry is a key concern, but the interests of the special issue go far beyond. They include: the role of the European Commission in the development of EU policy, the politics of state aid, and a clash between models of capitalism. The special issue also examines the impact of EU policy. It investigates how EU state aid decisions affect not only industrial policy at the national level (and therefore at the EU level), but the welfare state and territorial relations within federal member states, the external implications of EU action and the strategies pursued by the Commission to limit any potential disadvantage to European firms, and the conflict between the EUâs expanding legal order and national
Questioning policy, youth participation and lifestyle sports
Young people have been identified as a key target group for whom participation in sport and physical activity could have important benefits to health and wellbeing and consequently have been the focus of several government policies to increase participation in the UK. Lifestyle sports represent one such strategy for encouraging and sustaining new engagements in sport and physical activity in youth groups, however, there is at present a lack of understanding of the use of these activities within policy contexts. This paper presents findings from a government initiative which sought to increase participation in sport for young people through provision of facilities for mountain biking in a forest in south-east England. Findings from qualitative research with 40 young people who participated in mountain biking at the case study location highlight the importance of non-traditional sports as a means to experience the natural environments through forms of consumption which are healthy, active and appeal to their identities. In addition, however, the paper raises questions over the accessibility of schemes for some individuals and social groups, and the ability to incorporate sports which are inherently participant-led into state-managed schemes. Lifestyle sports such as mountain biking involve distinct forms of participation which present a challenge for policy-makers who seek to create and maintain sustainable communities of youth participants
Zirconium trisulfide as a promising cathode material for Li primary thermal batteries
In this work ZrS3 has been synthesized by solid state reaction in a sealed quartz tube and investigated as a candidate cathode material in Li thermal batteries. The structure of ZrS3 before and after cell testing has been studied using powder X-ray diffraction. A new spinel related material, LiZr2S4, has been identified as the product of the electrochemical process, which can be indexed to a = 10.452(8) Ă
cubic unit cell. The electrochemical properties of the batteries were investigated at 500 °C against Li13Si4 by galvanostatic discharge and galvanostatic intermittent titration technique (GITT). In a thermal Li cell at 500 °C a single voltage plateau of 1.70 V at a current density of 11 mA/cm2 was achieved with capacity of 357 mA h g-1. Therefore ZrS3 material has some promise as a cathode for Li thermal batteries.Publisher PDFPeer reviewe
Climatic and environmental changes across the Early Eocene Climatic Optimum at mid-Waipara River, Canterbury Basin, New Zealand
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