217 research outputs found

    Optimal regimes with limited resources

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    Policy-makers are often faced with the task of distributing a limited supply of resources. To support decision-making in these settings, statisticians are confronted with two challenges: estimands are defined by allocation strategies that are functions of features of all individuals in a cluster; and relatedly the observed data are neither independent nor identically distributed when individuals compete for resources. Existing statistical approaches are inadequate because they ignore at least one of these core features. As a solution, we develop theory for a general policy class of dynamic regimes for clustered data, covering existing results in classical and interference settings as special cases. We cover policy-relevant estimands and articulate realistic conditions compatible with resource-limited observed data. We derive identification and inference results for settings with a finite number of individuals in a cluster, where the observed dataset is viewed as a single draw from a super-population of clusters. We also consider asymptotic estimands when the number of individuals in a cluster is allowed to grow; under explicit conditions, we recover previous results, thereby clarifying when the use of existing methods is permitted. Our general results lay the foundation for future research on dynamic regimes for clustered data, including the longitudinal cluster setting

    Rock and stiff-Soil site amplification: Dependency on VS30 and Kappa (Îș0)

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    A ground‐motion prediction equation (GMPE) specific to rock and stiff‐soil sites is derived using seismic motion recorded on high VS30 sites in Japan. This GMPE applies to events with 4.5≀Mw≀6.9 and VS30 ranging from 500 to 1500  m/s (stiff‐soil to rock sites). The empirical site coefficients obtained and the comparison with the simulated site functions show that seismic motion on rock and stiff‐soil sites does not depend only on VS30, but also on the high‐frequency attenuation site properties (Îș0). The effects of the site‐specific Îș0 on site amplification are analyzed using stochastic simulations, with the need to take into account both of these parameters for rock‐site adjustments. Adding the site‐specific Îș0 into the GMPEs thus appears to be essential in future work. The rock‐site stochastic ground‐motion simulations show that the site‐specific Îș0 controls the frequency corresponding to the maximum response spectral acceleration (famp1). This observation is used to link the peak of the response spectral shape to Îș0 in this specific Japanese dataset and then to add the effects of high‐frequency attenuation into the previous GMPE from the peak ground acceleration and up to periods of 0.2 s. The inclusion of Îș0 allows the observed bias to be corrected for the intraevent residuals and thus reduces sigma. However, this Îș0 determination is limited to a minimum number of rock‐site records with Mw≄4.5 and to distances of less than 50 km

    Prise en charge et coûts de la bronchopneumopathie chronique obstructive en France en 2011

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    RĂ©sumĂ©IntroductionCette Ă©tude vise Ă  estimer une prĂ©valence de la bronchopneumopathie chronique obstructive (BPCO) traitĂ©e et les coĂ»ts associĂ©s par degrĂ© de sĂ©vĂ©ritĂ©.MĂ©thodeElle a Ă©tĂ© conduite sur les donnĂ©es 2011 de l’échantillon gĂ©nĂ©raliste de bĂ©nĂ©ficiaires (EGB). Cet Ă©chantillon reprĂ©sente 1/97e des bĂ©nĂ©ficiaires des principaux rĂ©gimes d’assurance maladie obligatoire. Les cas et leur sĂ©vĂ©ritĂ© ont Ă©tĂ© identifiĂ©s Ă  partir d’algorithmes originaux. Les coĂ»ts ont Ă©tĂ© Ă©tablis dans une perspective collective.RĂ©sultatsLe taux de prĂ©valence minimale de la BPCO traitĂ©e a Ă©tĂ© estimĂ© Ă  3,8 % dans la population ĂągĂ©e de 40ans et plus, et 1,9 % tous Ăąges confondus. La population (58,2 % d’hommes) avait 68,8±12,7ans d’ñge moyen. Au total, 6,2 % des patients ont eu des consommations de soins Ă©vocatrices d’un stade trĂšs sĂ©vĂšre, 8,1 %, 13,8 % et 71,9 % d’un stade sĂ©vĂšre, modĂ©rĂ© ou peu sĂ©vĂšre. Sur une annĂ©e, 28,8 % ont consultĂ© un pneumologue, 5,0 % ont Ă©tĂ© hospitalisĂ©s (≄24h) pour BPCO et 6,7 % sont dĂ©cĂ©dĂ©s. En moyenne, les patients ont eu 1,7±1,5 exacerbations/an et seulement 61,4 % ont reçu un traitement mĂ©dicamenteux spĂ©cifique. La consommation annuelle moyenne de soins d’un patient a Ă©tĂ© estimĂ©e Ă  9382€ dont 5516€ attribuable Ă  la BPCO.ConclusionCette Ă©tude utilisant des bases de donnĂ©es mĂ©dico-administratives confirme l’importance du fardeau Ă©pidĂ©miologique et Ă©conomique de la BPCO en France.SummaryObjectivesTo estimate the prevalence of treated chronic obstructive pulmonary disease (COPD) and its associated costs by stage of severity.MethodsThe study was conducted on the 2011 data of the french general beneficiary sample database (EGB). EGB is a 1/97th sample of the whole population of the beneficiaries of the main compulsory national health insurances. COPD cases and the level of severity of the disease have been identified using new algorithms established from the available parameters in EGB. Costs were estimated using a collective perspective.ResultsThe minimal prevalence of treated COPD was estimated at 3.8% in patients of 40 years and older and 1.9% regardless of the age of individuals. This population was predominantly male (58.2%) with a mean age of 68.8 years (±12.7). A total of 6.2% of patients had a health-care utilization suggestive of a very severe stage of COPD and 8.1%, 13.8% and 71.9% suggestive of severe, moderate and mild stages respectively. Over one year, 28.8% of patients visited a specialist respiratory physician, 5.0% were hospitalized (≄24h) for COPD and 6.7% died. Patients experienced an average of 1.7 (±1.5) exacerbations per year and only 61.4% received specific pharmacological treatment for COPD during the year. The average yearly health-care cost of a patient with COPD was estimated at €9382, with €5342 directly related to COPD.ConclusionThis study based on medico-administrative databases confirms the high epidemiological and economic burden of COPD in France

    Interference estimated time of arrival on a 6-DOF cable-driven haptic foot platform

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    A Cable-Driven Locomotion Interface employs two independent cable-driven haptic foot platforms constrained in six degrees of freedom (6-DOF). Its control system and its geometry are designed for performing a wide range of trajectories that could generate cable interferences. This paper presents and analyzes computational methods for determining which cable can be released from an active actuation state while allowing control in a minimal tension state, thereby ensuring that both platforms stay in a controllable workspace. One challaging task is to develop light and fast computational algorithms for hard real time processes included in haptic display applications. Seeing that releasing a cable from an active actuation state might generate discontinuities in tension values in the other cables, this paper proposes collision prediction schemes named Interference Estimated Time of Arrival in order to reduce or completely eliminate such discontinuities

    Together, yet still not equal? Sex integration in equestrian sport

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    Sex segregation is a core organising principle of most modern sports and is a key element in the marginalisation and subordination of girls and women in sport and beyond. In this article I explore the only Olympic-level sport which is not organised around sex segregation – equestrian sport – in order to consider the implications of sex integration for female participants. I draw on a study conducted on elite riders that found that although sex integration in equestrian sport does not lead to female participants being excluded from high-level competition, men continue to perform disproportionately well. This suggests that although sex integration may be an important step towards breaking down gender hierarchies in sport, without accompanying wider changes in gender norms and expectations, sex integration alone will not be enough to achieve greater gender equality in equestrian sport

    Elucidating the Influence of the Activation Energy on Reaction Rates by Simulations Based on a Simple Particle Model

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    An application for visualizing the dynamic properties of an equimolar binary mixture of isotropic reactive particles is presented. By introducing a user selectable choice for the activation energy, the application is useful to demonstrate qualitatively that the reaction rate depends on the above choice and on temperature. The application is based on a 2D realistic dynamic model where atoms move because of their thermal energies and the trajectories are determined by solving numerically Newton’s laws according to a Molecular Dynamics (MD) scheme. Collisions are monitored as time progresses, and every time the collision energy is larger than the selected activation energy, a reactive event occurs. By examining the time evolution of the configurations, it is possible to observe that the number of reactive collisions is always smaller than the total number of collisions. However, the number of reactive events increases on raising the temperature and/or by decreasing the activation energy. The above observations, as well as more quantitative analyses of the simulation data, are useful in elucidating the connections existing among particle kinetic energy, temperature, and activation energy of the reaction. The application can be used at different levels of detail and in different instruction levels. Qualitative visual observations of the progress of the reaction are suitable at all levels of instruction. Systematic investigations on the effect of changes of temperature and activation energy, suitable for senior high school and college courses and useful to gain insight into kinetic models and Arrhenius’ law, are also reported

    Selection of suitable reference genes for quantitative real-time polymerase chain reaction in human meningiomas and arachnoidea

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    <p>Abstract</p> <p>Findings</p> <p>At first 32 housekeeping genes were analyzed in six randomly chosen meningiomas, brain and dura mater using geNorm, NormFinder, Bestkeeper-1 software and the comparative ΔCt method. Reference genes were ranked according to an integration tool for analyzing reference genes expression based on those four algorithms. Eight highest ranked reference genes (CASC3, EIF2B1, IPO8, MRPL19, PGK1, POP4, PPIA, and RPL37A) plus GAPDH and ACTB were then analyzed in 35 meningiomas, arachnoidea, dura mater and normal brain. NormFinder and Bestkeeper-1 identified RPL37A as the most stable expressed gene in meningiomas and their normal control tissue. NormFinder also determined the best combination of genes: RPL37A and EIF2B1. Commonly used reference genes GAPDH and ACTB were considered least stable genes. The critical influence of reference genes on qPCR data analysis is shown for VEGFA transcription patterns.</p> <p>Background</p> <p>In meningiomas quantitative real-time reverse transcription-polymerase chain reaction (qPCR) is most frequently used for accurate determination of gene expression using various reference genes. Although meningiomas are a heterogeneous group of tissue, no data have been reported to validate reference genes for meningiomas and their control tissues.</p> <p>Conclusions</p> <p>RPL37A is the optimal single reference gene for normalization of gene expression in meningiomas and their control tissues, although the use of the combination of RPL37A and EIF2B1 would provide more stable results.</p

    Understanding Action and Adventure Sports Participation-An Ecological Dynamics Perspective.

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    Previous research has considered action and adventure sports using a variety of associated terms and definitions which has led to confusing discourse and contradictory research findings. Traditional narratives have typically considered participation exclusively as the pastime of young people with abnormal characteristics or personalities having unhealthy and pathological tendencies to take risks because of the need for thrill, excitement or an adrenaline 'rush'. Conversely, recent research has linked even the most extreme forms of action and adventure sports to positive physical and psychological health and well-being outcomes. Here, we argue that traditional frameworks have led to definitions, which, as currently used by researchers, ignore key elements constituting the essential merit of these sports. In this paper, we suggest that this lack of conceptual clarity in understanding cognitions, perception and action in action and adventure sports requires a comprehensive explanatory framework, ecological dynamics which considers person-environment interactions from a multidisciplinary perspective. Action and adventure sports can be fundamentally conceptualized as activities which flourish through creative exploration of novel movement experiences, continuously expanding and evolving beyond predetermined environmental, physical, psychological or sociocultural boundaries. The outcome is the emergence of a rich variety of participation styles and philosophical differences within and across activities. The purpose of this paper is twofold: (a) to point out some limitations of existing research on action and adventure sports; (b) based on key ideas from emerging research and an ecological dynamics approach, to propose a holistic multidisciplinary model for defining and understanding action and adventure sports that may better guide future research and practical implications
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