87 resultados para agility, power law, motion analysis, radius of curvature
Resumo:
There is a growing incentive for sociologists to demonstrate the use value of their research. Research ‘impact’ is a driver of research funding and a measure of academic standing. Academic debate on this issue has intensified since Burawoy’s (2004) call for a ‘public’ sociology. However the academy is no longer the sole or primary producer of knowledge and empirical sociologists need to contend with the ‘huge swathes’ of social data that now exist (Savage and Burrows, 2007). This article furthers these debates by considering power struggles between competing forms of knowledge. Using a case study, it specifically considers the power struggle between normative and empirical knowledge, and how providers of knowledge assert legitimacy for their truth claims. The article concludes that the idea of ‘impact’ and ‘use-value’ are extremely complex and depends in the policy context on knowledge power struggles, and on how policy makers want to view the world. © The Author(s) 2012
Resumo:
An approach for evaluation of binding selectivity was suggested and exemplified using glycine/NMDA and AMPA receptors. For analyzing the pairwise selectivity, we propose to use the difference between biological activities (expressed as -log Ki) of ligands with respect to different receptor subtypes as a dependent variable for building comparative molecular field analysis (CoMFA) models. The resulting fields (which will be referred to as the "selectivity fields") indicate the ways of increasing selectivity of binding, inhibition, etc. As an example, CoMFA of a set of pyrazolo[1,5-c]quinazolines and triazolo[1,5-c]quinazolines was used for considering the binding selectivity with respect to glycine/NMDA and AMPA receptors. In addition, the mapping of these fields onto the molecular models of the corresponding receptors makes it possible to reveal the reasons for experimentally observed selectivity as well as to suggest additional ways of increasing selectivity.
Resumo:
This article concerns the legal issues that surround the prohibition of doping in sport. The current policy on the use of performance enhancing drugs (PEDs) in sport is underpinned by both a paternalistic desire to protect athletes’ health and the long-term integrity or ‘spirit’ of sport. The policy is put into administrative effect globally by the World Anti-Doping Agency (WADA), which provides the regulatory and legal framework through which the vast majority of international sports federations harmonise their anti-doping programmes. On outlining briefly both the broad administrative structures of international sport’s various anti-doping mechanisms, and specific legal issues that arise in disciplinary hearings involving athletes accused of doping, this article questions the sustainability of the current ‘zero tolerance’ approach, arguing, by way of analogy to the wider societal debate on the criminalisation of drugs, and as informed by Sunstein and Thaler’s theory of libertarian paternalism, that current policy on anti-doping has failed. Moreover, rather than the extant moral and punitive panic regarding doping in sport, this article, drawing respectively on Seddon’s and Simon’s work on the history of drugs and crime control mentality, contends that, as an alternative, harm reductionist measures should be promoted, including consideration of the medically supervised use of certain PEDs.
Resumo:
The electronic stopping power of H and He moving through gold is obtained to high accuracy using time-evolving density-functional theory, thereby bringing usual first principles accuracies into this kind of strongly coupled, continuum nonadiabatic processes in condensed matter. The two key unexplained features of what observed experimentally have been reproduced and understood: (i)The nonlinear behavior of stopping power versus velocity is a gradual crossover as excitations tail into the d-electron spectrum; and (ii)the low-velocity H/He anomaly (the relative stopping powers are contrary to established theory) is explained by the substantial involvement of the d electrons in the screening of the projectile even at the lowest velocities where the energy loss is generated by s-like electron-hole pair formation only. © 2012 American Physical Society.
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Motion of single micrometer-sized magnetic particles on patterned magnetic surfaces is controlled by a rotating magnetic field (see Figure and cover). Patterns of thin-film magnetic elements are tailored to form transport lines. Individual particles are separated by adding junctions to the transport lines. The method can improve existing applications in biotechnology and generate new ones in life sciences.
Resumo:
Linear acceleration emission occurs when a charged particle is accelerated parallel to its velocity. We evaluate the spectral and angular distribution of this radiation for several special cases, including constant acceleration (hyperbolic motion) of finite duration. Based on these results, we find the following general properties of the emission from an electron in a linear accelerator that can be characterized by an electric field E acting over a distance L: (1) the spectrum extends to a cutoff frequency (h) over bar omega(c)/mc(2) approximate to L(E/E(Schw))(2)/(lambda) over bar (C), where E(Schw) = 1.3 x 10(18) V m(-1) is the Schwinger critical field and (lambda) over bar (C) = (h) over bar /mc = 3.86 x 10(-13) m is the Compton wavelength of the electron, (2) the total energy emitted by a particle traversing the accelerator is 4/3 alpha(f)(h) over bar omega(c) in accordance with the standard Larmor formula where alpha(f) is the fine-structure constant, and (3) the low frequency spectrum is flat for hyperbolic trajectories, but in general depends on the details of the accelerator. We also show that linear acceleration emission complements curvature radiation in the strongly magnetized pair formation regions in pulsar magnetospheres. It dominates when the length L of the accelerator is less than the formation length rho/gamma of curvature photons, where rho is the radius of curvature of the magnetic field lines and gamma the Lorentz factor of the emitting particle. In standard static models of pair creating regions linear acceleration emission is negligible, but it is important in more realistic dynamical models in which the accelerating field fluctuates on a short length scale.
E-motion: tutors’ experiences of the transition to e-portfolio use in pre-service teacher education.
Resumo:
We develop a theory for the food intake of a predator that can switch between multiple prey species. The theory addresses empirical observations of prey switching and is based on the behavioural assumption that a predator tends to continue feeding on prey that are similar to the prey it has consumed last, in terms of, e.g., their morphology, defences, location, habitat choice, or behaviour. From a predator's dietary history and the assumed similarity relationship among prey species, we derive a general closed-form multi-species functional response for describing predators switching between multiple prey species. Our theory includes the Holling type II functional response as a special case and makes consistent predictions when populations of equivalent prey are aggregated or split. An analysis of the derived functional response enables us to highlight the following five main findings. (1) Prey switching leads to an approximate power-law relationship between ratios of prey abundance and prey intake, consistent with experimental data. (2) In agreement with empirical observations, the theory predicts an upper limit of 2 for the exponent of such power laws. (3) Our theory predicts deviations from power-law switching at very low and very high prey-abundance ratios. (4) The theory can predict the diet composition of a predator feeding on multiple prey species from diet observations for predators feeding only on pairs of prey species. (5) Predators foraging on more prey species will show less pronounced prey switching than predators foraging on fewer prey species, thus providing a natural explanation for the known difficulties of observing prey switching in the field. (C) 2013 Elsevier Ltd. All rights reserved.
Resumo:
The European Union has set a target of 20% for the share of renewable energy sources in gross final energy consumption in 2020. These renewable energy targets are priority objectives for the Europe 2020 strategy for inclusive growth. In line with the European Union renewable energy policies, the Northern Ireland Executive has a target to deliver 40% renewable electricity by 2020. Currently, Northern Ireland imports 98% of the energy it uses in the form of fossil fuels. Locally produced energy and electricity is needed to ensure sustainable development. The aim of this research is to develop part of a strategy for the mechanical power take-off system for a flap type wave energy converter. Aquamarine Power Ltd’s Oyster flap was the device used for simulation and testing purposes. In this paper the state-of-the-art of wave energy converters is reviewed and a 40th scale test model was developed and built.
Resumo:
EU non-discrimination law has seen a proliferation of discrimination grounds from 2000. Dis-crimination on grounds of gender (in the field of equal pay) and on grounds of nationality (generally within the scope of application of EU law) were the only prohibited forms of discrimination in EU law, until the Treaty of Amsterdam empowered the Community to legislate in order to combat discrimination on grounds of sex, racial or ethnic origin, religion or belief, disability, age or sexual orientation (Article 13 EC). Proliferation of non-discrimination grounds is also characteristic for international and national non-discrimination law. As such, proliferation of grounds results in an increase in potential cases of “multiple discrimination” and the danger of diluting the demands of equality law by ever more multiplication of grounds. The hierarchy of equality, which has been so widely criticised in EU law, is a signifier of the latter danger.
This chapter proposes to structure the confusing field of non-discrimination grounds by organising them around nodes of discrimination fields. It will first reflect different ways of establishing hierarchies between grounds. This will be followed by a recount of different (narrow and wide) reading of grounds. A comprehensive reading of the grounds gender, ‘race’ and disability as establishing overlapping fields of discrimination grounds will be mapped out, with some examples for practical uses.