1,638 research outputs found

    Factors Associated to Purchase of Quality-Labelled Beef

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    The aim of the present study is to identify the factors associated to purchase of quality-labelled beef. For this purpose a total of 364 surveys were carried out on buyers of beef in three Spanish cities. The sample was divided into three groups of buyers according to the beef purchasing habits with a quality label. A logistic regression analysis was used to estimate the differences between groups. The results show the importance of the production region as a quality aspect. Income level, association of quality-labelled beef with “guarantee and tradition” aspects, purchasing frequency, place of purchase, production systems and lifestyles are all variables that enabled us to establish differences between groups.beef quality, quality label, consumer perception, Demand and Price Analysis,

    Monitoring and evaluating business mentoring: towards a research and evaluation toolkit to measure impact

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    This paper presents a Research and Evaluation Toolkit (RET) which has applicability to mentoring programmes in all sectors and organizational contexts. The RET offers a practical guide for human resource development practitioners engaged in evaluation of learning and development programmes and more specifically, mentoring. The RET was a key outcome of a global 2.5-year impact evaluation project with Youth Business International and Middlesex University Business School, evaluating the impact of volunteer business mentoring on under-served young entrepreneurs and their business ventures. This paper brings to the forefront the importance of integrating a measurement and evaluation strategy from the initial mentoring programme design phase and ongoing management. Despite the growing number of survey reports and studies that highlight the importance of this aspect of mentoring programme design and management, measurement and evaluation continues to be one of the most challenging areas. As such, this paper contributes to our understanding concerning the role and effectiveness of ongoing monitoring and evaluation in relation to demonstrating the impact of human resource development interventions and provides a practical approach for practitioners to develop and enhance their evaluation strategy and methods. Key words: research and evaluation, business mentoring, impac

    Prevention, screening and treatment of colorectal cancer: a global and regional generalized cost effectiveness analysis

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    <p>Abstract</p> <p>Background</p> <p>Regional generalized cost-effectiveness estimates of prevention, screening and treatment interventions for colorectal cancer are presented.</p> <p>Methods</p> <p>Standardised WHO-CHOICE methodology was used. A colorectal cancer model was employed to provide estimates of screening and treatment effectiveness. Intervention effectiveness was determined via a population state-transition model (PopMod) that simulates the evolution of a sub-regional population accounting for births, deaths and disease epidemiology. Economic costs of procedures and treatment were estimated, including programme overhead and training costs.</p> <p>Results</p> <p>In regions characterised by high income, low mortality and high existing treatment coverage, the addition of screening to the current high treatment levels is very cost-effective, although no particular intervention stands out in cost-effectiveness terms relative to the others.</p> <p>In regions characterised by low income, low mortality with existing treatment coverage around 50%, expanding treatment with or without screening is cost-effective or very cost-effective. Abandoning treatment in favour of screening (no treatment scenario) would not be cost effective.</p> <p>In regions characterised by low income, high mortality and low treatment levels, the most cost-effective intervention is expanding treatment.</p> <p>Conclusions</p> <p>From a cost-effectiveness standpoint, screening programmes should be expanded in developed regions and treatment programmes should be established for colorectal cancer in regions with low treatment coverage.</p

    Quantum dissipation due to the interaction with chaotic degrees-of-freedom and the correspondence principle

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    Both in atomic physics and in mesoscopic physics it is sometimes interesting to consider the energy time-dependence of a parametrically-driven chaotic system. We assume an Hamiltonian H(Q,P;x(t)){\cal H}(Q,P;x(t)) where x(t)=Vtx(t)=Vt. The velocity VV is slow in the classical sense but not necessarily in the quantum-mechanical sense. The crossover (in time) from ballistic to diffusive energy-spreading is studied. The associated irreversible growth of the average energy has the meaning of dissipation. It is found that a dimensionless velocity vPRv_{PR} determines the nature of the dynamics, and controls the route towards quantal-classical correspondence (QCC). A perturbative regime and a non-perturbative semiclassical regime are distinguished.Comment: 4 pages, clear presentation of the main poin

    Computational Method for Phase Space Transport with Applications to Lobe Dynamics and Rate of Escape

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    Lobe dynamics and escape from a potential well are general frameworks introduced to study phase space transport in chaotic dynamical systems. While the former approach studies how regions of phase space are transported by reducing the flow to a two-dimensional map, the latter approach studies the phase space structures that lead to critical events by crossing periodic orbit around saddles. Both of these frameworks require computation with curves represented by millions of points-computing intersection points between these curves and area bounded by the segments of these curves-for quantifying the transport and escape rate. We present a theory for computing these intersection points and the area bounded between the segments of these curves based on a classification of the intersection points using equivalence class. We also present an alternate theory for curves with nontransverse intersections and a method to increase the density of points on the curves for locating the intersection points accurately.The numerical implementation of the theory presented herein is available as an open source software called Lober. We used this package to demonstrate the application of the theory to lobe dynamics that arises in fluid mechanics, and rate of escape from a potential well that arises in ship dynamics.Comment: 33 pages, 17 figure

    Spitzer Observations of IC 2118

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    IC 2118, also known as the Witch Head Nebula, is a wispy, roughly cometary, ~5 degree long reflection nebula, and is thought to be a site of triggered star formation. In order to search for new young stellar objects (YSOs), we have observed this region in 7 mid- and far-infrared bands using the Spitzer Space Telescope and in 4 bands in the optical using the U. S. Naval Observatory 40-inch telescope. We find infrared excesses in 4 of the 6 previously-known T Tauri stars in our combined infrared maps, and we find 6 entirely new candidate YSOs, one of which may be an edge-on disk. Most of the YSOs seen in the infrared are Class II objects, and they are all in the "head" of the nebula, within the most massive molecular cloud of the region.Comment: Accepted to Ap

    Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction

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    Severe changes in ocean redox, nutrient cycling, and marine productivity accompanied most Phanerozoic mass extinctions. However, evidence for marine photic zone euxinia (PZE) as a globally important extinction mechanism for the end-Triassic extinction (ETE) is currently lacking. Fossil molecular (biomarker) and nitrogen isotopic records from a sedimentary sequence in western Canada provide the first conclusive evidence of PZE and disrupted biogeochemistry in neritic waters of the Panthalassic Ocean during the end Triassic. Increasing water-column stratification and deoxygenation across the ETE led to PZE in the Early Jurassic, paralleled by a perturbed nitrogen cycle and ecological turnovers among noncalcifying groups, including eukaryotic algae and prokaryotic plankton. If such conditions developed widely in the Panthalassic Ocean, PZE might have been a potent mechanism for the ETE.National Science Foundation (U.S.) (Grant EAR-1147402)Exobiology Program (U.S.) (Grants NNX09AM88G and NNA08CN84A)American Association of Petroleum Geologists (Grant-In-Aid)Mary-Hill and Bevan M. French Fund for Impact Geolog

    Semiclassical analysis of the quantum interference corrections to the conductance of mesoscopic systems

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    The Kubo formula for the conductance of a mesoscopic system is analyzed semiclassically, yielding simple expressions for both weak localization and universal conductance fluctuations. In contrast to earlier work which dealt with times shorter than O(log1)O(\log \hbar^{-1}), here longer times are taken to give the dominant contributions. For such long times, many distinct classical orbits may obey essentially the same initial and final conditions on positions and momenta, and the interference between pairs of such orbits is analyzed. Application to a chain of kk classically ergodic scatterers connected in series gives the following results: 13[1(k+1)2]-{1 \over 3} [ 1 - (k+1)^{-2} ] for the weak localization correction to the zero--temperature dimensionless conductance, and 215[1(k+1)4]{2 \over 15} [ 1 - (k+1)^{-4} ] for the variance of its fluctuations. These results interpolate between the well known ones of random scattering matrices for k=1k=1, and those of the one--dimensional diffusive wire for kk \rightarrow \infty.Comment: 53 pages, using RevTeX, plus 3 postscript figures mailed separately. A short version of this work is available as cond-mat/950207
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