700 research outputs found
Passivity-Based Output-Feedback Control of Turbulent Channel Flow
This paper describes a robust linear time-invariant output-feedback control strategy to reduce turbulent fluctuations, and therefore skin-friction drag, in wall-bounded turbulent fluid flows, that nonetheless gives performance guarantees in the nonlinear turbulent regime. The novel strategy is effective in reducing the supply of available energy to feed the turbulent fluctuations, expressed as reducing a bound on the supply rate to a quadratic storage function. The nonlinearity present in the equations that govern the dynamics of the flow is known to be passive and can be considered as a feedback forcing to the linearised dynamics (a Lurâe decomposition). Therefore, one is only required to control the linear dynamics in order to make the system close to passive. The ten most energy-producing spatial modes of a turbulent channel flow were identified. Passivity-based controllers were then generated to control these modes. The controllers require measurements of streamwise and spanwise wall-shear stress, and they actuate via wall transpiration. Nonlinear direct numerical simulations demonstrated that these controllers were capable of significantly reducing the turbulent energy and skin-friction drag of the flow
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Languages and Learning at Key Stage 2: A Longitudinal Study Final Report
In 2006, The Open University, the University of Southampton and Canterbury Christ Church University were commissioned by the then Department for Education and Skills (DfES), now Department for Children, Schools and Families (DCSF) to conduct a three-year longitudinal study of languages learning at Key Stage 2 (KS2). The qualitative study was designed to explore provision, practice and developments over three school years between 2006/07 and 2008/09 in a sample of primary schools and explore childrenâs achievement in oracy and literacy, as well as the possible broader cross-curricular impact of languages learning
Asymptotic behaviour of multiple scattering on infinite number of parallel demi-planes
The exact solution for the scattering of electromagnetic waves on an infinite
number of parallel demi-planes has been obtained by J.F. Carlson and A.E. Heins
in 1947 using the Wiener-Hopf method. We analyze their solution in the
semiclassical limit of small wavelength and find the asymptotic behaviour of
the reflection and transmission coefficients. The results are compared with the
ones obtained within the Kirchhoff approximation
Antiquities trafficking in conflict countries: A crime-mapping approach
Studies on antiquities trafficking have often been overshadowed by research looking at the trafficking of human beings, drugs, and weapons, a fact partly motivated by the arguably higher relevance and greater security implications involved in these other forms of illicit trade. However, the past decade of conflicts in the Middle East has revived an interest in the study of antiquities trafficking networks. 1 The association between the growing size of the illicit antiquities market and conflicts in the region did not go unnoticed by crime scientists and criminologists looking deeper at the relation between the trafficking of antiquities and transnational organized crime
Genetic selection for reduced health treatment costs in Holstein cows: implications from a long-term study
The objective of this study was to estimate genetic parameters of health treatment cost of Holstein cows from producer-recorded health treatments in 8 herds over an 8-yr period of time. Genetic parameters of health treatment cost were estimated in first (n = 2,214), second (n = 1,487) and third (n = 800) parities of US Holstein cows. The health treatments were uniformly defined and consistently recorded by 8 high-performance dairy herds in Minnesota from 2008 to 2015. A fixed treatment cost was assigned to 14 types of health treatments, and the cost included the mean veterinary expense obtained from the veterinary clinics that serviced the 8 herds, pharmaceuticals, and labor cost. The labor cost was $18/h, and the time incurred for each type of health treatment was determined from interviews with the herd owners. The 14 types of health treatment costs were partitioned into 5 categories: mastitis (including mastitis diagnostic test), reproduction (cystic ovary, retained placenta, and metritis), lameness (hoof treatments), metabolic (milk fever, displaced abomasum, ketosis, and digestive), and miscellaneous (respiratory, injury, and other). Health treatment cost for each cow was summed by category within lactation and also across categories within lactation. The estimates of heritability for health treatment cost were 0.13, 0.04, 0.10, 0.12, and 0.04 for the mastitis, reproduction, lameness, metabolic, and miscellaneous categories, respectively, in first parity. Genetic correlations between categories of health treatment cost in first parity were greatest for mastitis and reproduction (r = 0.85); however, phenotypic correlations between all categories were small (r < 0.16). Total health treatment cost had a large genetic correlation with somatic cell score (0.93) and 305-d milk production (0.44) in first parity; however, the genetic correlation (â0.60) between total health treatment cost and udder depth in first parity indicated a genetic relationship exists between shallow udders and less total health treatment cost. Total health treatment cost across categories had a heritability estimate of 0.25 in first parity, 0.16 in second parity, and 0.17 in third parity. Consequently, genetic selection for reduced health treatment cost should be possible by using producer-recorded health treatment records supplemented with treatment costs
Az orvosnĆi hivatĂĄs magatartĂĄstudomĂĄnyi vizsgĂĄlata = Behavioural sciences perspective of the medical profession by female physicians
Jelen tanulmĂĄnyunk folytatni kĂvĂĄnja azt a 16 Ă©vvel ezelĆtt kĂ©szĂŒlt munkĂĄt, amely a magyarÂorszĂĄgi orvosok/orvosnĆk egĂ©szsĂ©gi ĂĄllapotĂĄt, Ă©letminĆsĂ©gĂ©t tĂĄrta fel. A kiugrĂłan rossz mortalitĂĄsi Ă©s morbiditĂĄsi mutatĂłk hĂĄtterĂ©ben akkor az egyenlĆtlen terhelĂ©s, a mozgĂĄsszegĂ©ny Ă©letmĂłd Ă©s a kedvezĆtlen Ă©letkörĂŒlmĂ©nyek szerepeltek magyarĂĄzĂł vĂĄltozĂłkĂ©nt. 2001 tavaszĂĄn 72 orvosnĆvel kĂ©szĂtettĂŒnk Ă©letĂșt-interjĂșt, Ă©s vettĂŒnk fel az egĂ©szsĂ©gi ĂĄllapotukra vonatkozĂł kĂ©rdĆĂvet. VizsgĂĄlatunk legfĆbb cĂ©lja az volt, hogy feltĂ©rkĂ©pezzĂŒk az orvosnĆk hivatĂĄsbeli Ă©s csalĂĄdi terheinek alakulĂĄsĂĄt, megvizsgĂĄljuk az egĂ©szsĂ©gĂŒgyi problĂ©mĂĄkat, a szerepkonfliktusokat, illetve ezek megoldĂĄsi kĂsĂ©rleteit. KutatĂĄsunk az Ă©letĂșt szĂĄmos fontos elemĂ©t igyekezett megvizsgĂĄlni: a pĂĄlyavĂĄlasztĂĄs, szakvĂĄlasztĂĄs kĂ©rdĂ©sĂ©tĆl a munkahelyeken ĂĄt a csalĂĄd Ă©s az anyasĂĄg kĂ©rdĂ©sĂ©ig. MunkĂĄnk ugyanakkor elĆtanulmĂĄnynak tekinthetĆ, amely kĂ©sĆbbi egĂ©szsĂ©gi ĂĄllapottal Ă©s szerepkonfliktussal kapcsolatos orszĂĄgos vizsgĂĄlat alapjĂĄul szolgĂĄlhat
Transport by molecular motors in the presence of static defects
The transport by molecular motors along cytoskeletal filaments is studied
theoretically in the presence of static defects. The movements of single motors
are described as biased random walks along the filament as well as binding to
and unbinding from the filament. Three basic types of defects are
distinguished, which differ from normal filament sites only in one of the
motors' transition probabilities. Both stepping defects with a reduced
probability for forward steps and unbinding defects with an increased
probability for motor unbinding strongly reduce the velocities and the run
lengths of the motors with increasing defect density. For transport by single
motors, binding defects with a reduced probability for motor binding have a
relatively small effect on the transport properties. For cargo transport by
motors teams, binding defects also change the effective unbinding rate of the
cargo particles and are expected to have a stronger effect.Comment: 20 pages, latex, 7 figures, 1 tabl
Between learning and schooling: the politics of human rights monitoring at the Universal Periodic Review
This paper explores the politics of monitoring at the Universal Periodic Review (UPR), a new United Nations human rights monitoring mechanism which aims to promote a universal approach and equal treatment when reviewing each countryâs human rights situation. To what extent are these laudable aims realised, and realisable, given entrenched representations of the West and the Rest as well as geopolitical and economic inequalities both historically and in the present? Based on ethnographic fieldwork at the UN in 2010â11, the final year of the UPRâs first cycle, we explore how these aims were both pursued and subverted, paying attention to two distinct ways of talking about the UPR: first, as a learning culture in which UN member states âshare best practiceâ and engage in constructive criticism; and second, as an exam which UN member states face as students with vastly differing attitudes and competences. Accounts and experiences of diplomats from states that are not placed in the âgood studentsâ category offer valuable insights into the inherent contradictions of de-historicised and de-contextualised approaches to human rights
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