Properties of iterative Monte Carlo single histogram reweighting

We present iterative Monte Carlo algorithm for which the temperature variable is attracted by a critical point. The algorithm combines techniques of single histogram reweighting and linear filtering. The 2d Ising model of ferromagnet is studied numerically as an illustration. In that case, the iterations uncovered stationary regime with invariant probability distribution function of temperature which is peaked nearly the pseudocritical temperature of specific heat. The sequence of generated temperatures is analyzed in terms of stochastic autoregressive model. The error of histogram reweighting can be better understood within the suggested model. The presented model yields a simple relation, connecting variance of pseudocritical temperature and parameter of linear filtering.Comment: 3 figure

Experiences of using a wearable camera to record activity, participation and health-related behaviours: Qualitative reflections of using the Sensecam

Objective: Upcoming technology is changing the way that we are able to collect data looking into activity, social participation and health behaviours. Wearable cameras are one form of technology that allows us to automatically record a collection of passive images, building a visual diary of the user’s day. Whilst acknowledging the usefulness of wearable cameras in research, it is also important to understand individuals’ experiences whilst using them. The aim of this study was to explore the acceptance, experience and usability of a wearable camera (Microsoft_ Sensecam) to record the day-to-day activity and social participation of older people. Methods: A total of 18 older adults, who had worn the wearable camera for seven days, took part in semi-structured interviews. Results: Four themes emerged from the findings: ‘Intrusiveness’; ‘Importance of others’; ‘Remembering the wearable camera’; and ‘Ease of use’. Conclusions: Individuals’ expectations and experiences of using the wearable camera differed considerably. Participants believed that the wearable camera would be intrusive, difficult to use and would evoke public reaction; however, these worries were not borne out in experience. Individuals typically forgot about the presence of the wearable camera during use, remembering it only sporadically. One drawback to its use is that some participants were cautious of using the camera when around others, which impacted the amount of time the camera was worn, and, therefore, the nature of the data recorded. Design issues of the Sensecam were also a problem for the older adults in the study and affected their interaction with the technology

The use of a wearable camera to explore daily functioning of older adults living with persistent pain: Methodological reflections and recommendations

Background: Persistent pain is prevalent within the ageing population and impacts daily functioning. Measuring daily functioning using conventional measures is problematic and novel technologies offer an alternative way of observing these behaviours. Methods: This study aimed to consider the use of a wearable camera as a method of exploring a range of day-to-day patterns of functioning of older adults living with persistent pain. This study followed a mixed methods design. A purposive sample of 13 older adults (65±) with persistent pain (pain >3 months) took part in this study. Two younger adults (<65) with persistent pain and two older adults with no pain also participated. Individuals used a wearable camera (Microsoft SenseCam) for seven days Results: The wearable camera recorded the frequency of body position, movement, and activities of daily living. The wearable camera also presented contextual data of location, social interactions, use of assistive devices, and behavioural adaptations and was used to inform other methods of data collection. Conclusions: The wearable camera allowed insight into patterns and experiences of daily functioning that would not have otherwise been captured. However, not all aspects of functioning were recorded using the wearable camera, including the relationship between functioning and persistent pain

Cadre conceptuel pour définir la population statistique de l’économie sociale au Québec

Sous la direction de Marie J. BouchardL’objectif du cadre conceptuel est de fournir des concepts et des définitions pour guider la collecte de données et la production de statistiques cohérentes et comparables sur l’économie sociale québécoise. L’objectif est aussi de contribuer au développement de la recherche analytique sur l’économie sociale en identifiant des indicateurs pertinents pour la décrire quantitativement. Le cadre conceptuel doit être à la fois assez général pour témoigner de l’appartenance de l’économie sociale à un mouvement international, et assez particulier pour bien refléter son originalité québécoise. Dans ce document, nous employons le terme économie sociale dans une définition large et inclusive, couvrant les domaines de l’économie sociale coopérative, mutualiste et sans but lucratif ainsi que l’action communautaire et l’action communautaire autonome, tels que généralement reconnus au Québec. Le point de départ de la conceptualisation d’une définition « statistique » de l’économie sociale est la Définition de l’économie sociale adoptée au Québec en 1996. Cette définition, à l’instar d’autres définitions employées ailleurs dans le monde, montre la primauté de la finalité sociale sur l’activité économique. Ceci se manifeste notamment dans les traits empiriques qui sont caractéristiques des structures et du fonctionnement de l’économie sociale et qui la distinguent du reste de l’économie. Le cadre conceptuel qui en découle établit le type d’entités, les statuts juridiques, les secteurs d’activités exclus et un faisceau de critères de qualification des organisations de l’économie sociale. Il établit aussi une typologie des organisations. Le cadre conceptuel permet également d’évaluer les composantes périphériques du champ et de prévoir sa propre évolution (par ex. pour l’intégration de nouvelles organisations qui seraient reconnues d’économie sociale). Les entités de l’économie sociale sont des entreprises (au sens de Statistique Canada) ayant les statuts juridiques de coopératives, mutuelles, ou d’organismes sans but lucratif (OSBL). Le terme « entreprise » n’étant pas utilisé dans tous les milieux de l’économie sociale, nous employons le terme « organisations d’économie sociale » de manière à toutes les englober. Les secteurs du Système de comptabilité nationale du Canada (SCNC) les plus susceptibles à contenir des organisations d’économie sociale sont le secteur des sociétés non financières, celui des sociétés financières et celui des institutions sans but lucratif au service des ménages. Il est peu probable de trouver des organisations d’économie sociale dans les autres secteurs économiques du SCNC, à savoir le secteur de l’administration publique, celui des ménages, certaines parties du secteur des institutions du secteur public au service des ménages et le secteur des entreprises non constituées en sociétés. Certains secteurs d’activité du Système de classification des industries de l’Amérique du Nord (SCIAN) ne font pas partie de l’économie sociale : les organismes religieux, les regroupements patronaux, les regroupements professionnels, les syndicats et les partis politiques. Des critères permettent de qualifier les organisations qui font partie de l’économie sociale (et leurs filiales respectives) : la gouvernance démocratique; la distribution limitée ou interdite des excédents ; l’autonomie et l’indépendance ; et la production organisée de biens ou de services. Un seul de ces traits ne suffit pas pour caractériser l’économie sociale, et ces traits ne sont pas hiérarchisés entre eux. C’est plutôt un ensemble de traits, ou un « faisceau de critères », qui doit être observé pour qualifier l’économie sociale. L’opérationnalisation de ces critères se fait par tris successifs, du plus simple au plus exigeant sur le plan méthodologique, de manière à filtrer progressivement la population statistique de l’économie sociale. Au Québec, les statuts juridiques de la coopérative et de la mutuelle couvrent l’ensemble des critères du cadre conceptuel et permettent d’emblée de classer ces organisations dans le champ. Les organisations ayant un statut juridique d’organisme sans but lucratif rencontrent le critère de distribution limitée ou interdite des excédents, mais doivent être examinées pour établir (successivement, cette fois) qu’ils correspondent aux critères de : a) production organisée de biens ou de services ; b) autonomie et indépendance et c) gouvernance démocratique. Ainsi, puisque les organismes sans but lucratif peuvent être mis sur pied pour de multiples fins, seuls ceux qui produisent de manière organisée des biens ou des services font partie de l’économie sociale. Étant donné que les OSBL peuvent être contrôlés par des personnes ou des entités qui n’en sont pas les membres, seuls ceux qui sont exempts de contrôle externe font partie de l’économie sociale. Enfin, puisque OSBL n’ont pas d’obligation légale en matière d’inspection, seuls ceux qui peuvent témoigner du fonctionnement de leurs instances de gouvernance démocratique font partie de l’économie sociale. Le cadre conceptuel sert aussi à développer une typologie qui vise à rendre compte de dynamiques économiques différenciées des organisations d’économie sociale. Se basant sur la capacité d’hybridation des ressources qui caractérise l’économie sociale, la typologie établit six grands types d’organisations de l’économie sociale suivant le mode dominant d’allocation des ressources (échange marchand, redistribution ou réciprocité) et leur principale provenance (de source privée ou publique). Cette typologie n’est certes pas suffisante pour classer les entités de la population, mais elle est complémentaire à d’autres classifications existantes1. L’adaptation du cadre conceptuel aux particularités québécoises de l’économie sociale permet de tenir compte des entités qui, aux vues du cadre conceptuel, paraissent être des « exceptions » puisqu’elles ne correspondent pas aux critères du modèle logique, mais appartiennent néanmoins au « mouvement » de l’économie sociale du Québec. Quelques‐uns de ces cas sont analysés en détail et sont intégrés dans le Modèle logique opérationnel de l’économie sociale au Québec en 2011, qui reprend les étapes du cadre général et tient compte des particularités québécoises. Enfin, une analyse du cas des fondations permet de voir les caractéristiques de celles qui seraient le plus susceptibles d’être reconnues comme faisant partie de l’économie sociale si la définition québécoise venait à les inclure. Ce type d’analyse peut être repris pour d’autres organisations ou secteurs d’activités, dans le contexte où le cadre conceptuel viendrait à évoluer.The objective of the conceptual framework is to supply concepts and definitions to guide the data collection and the production of statistics which are coherent and comparable regarding Québec’s social economy. The objective is also to contribute to the development of analytical research on social economy by identifying relevant indicators to quantitatively describe it. The conceptual framework must be quite general to establish the fact that the social economy is part of an international movement and at the same time specific enough to properly reflect its Québec originality. In this document, we will use the term “social economy” in a large and inclusive definition, which will cover the fields of cooperative, mutual and non‐profit social economy, as well as community action and autonomous community action as generally acknowledged in Québec. The starting point of the conceptualization of the “statistical” definition of social economy is the Definition of Social Economy adopted in Québec in 1996. Like other definitions used elsewhere in the world, this definition underlines the primacy of social purpose over economic activity. This is especially shown in the empirical features which are typical of the structures and operation of the social economy and which distinguish it from the rest of the economy. The resulting conceptual framework establishes the type of entities, the legal status, sectors of activity which are excluded and a cluster of qualification criteria of social economy organizations. It also establishes a typology of organizations. The conceptual framework also allows assessing the peripheral components in this field and forecasting its own progress (for example, for the integration of new organizations which would be acknowledged as being part of the social economy). Social economy entities are enterprises (within the meaning given by Statistics Canada) which have legal status as cooperative, mutuals or non‐profit organizations (NPOs). Because the term “enterprise” is not used in all sectors of the social economy, we will use the term “social economy organizations” so as to include all of them. The sectors of the Canadian System of National Accounts (CSNA) which are the most likely to include social economy organizations are those of non‐financial corporations, financial corporations and non‐profit institutions serving households. It is highly improbable that social economy organizations will be found in other CSNA economic sectors, that is, the sectors of government, households, some parts of the government institutions serving households sector and the unincorporated business sector. Some sectors of activity of the North American Industry Classification System (NAICS) are not part of the social economy. These are religious organizations, employers’ associations, professional associations, trade unions and political parties. Some criteria allow qualifying organizations which are part of the social economy (and their respective subsidiaries): democratic governance; restricted or prohibited distribution of surplus; autonomy and independence; and the organized production of goods or services. Only one criterion is insufficient to characterize the social economy and there is no hierarchy of criteria. Instead, it is a series of features or a “cluster of features” which must be noted to qualify the social economy. The operationalization of these criteria is done through successive triage from the simplest to the most demanding from a methodological point of view, so as to progressively filter the statistical population of the social economy. In Québec, the legal status of the cooperative and mutual cover all of the criteria of the conceptual framework and allow classifying these organizations in this field. Organizations that have legal status as non‐profit organizations meet the criterion of limited or prohibited distribution of surplus, but they must be examined to determine (successively this time) if they correspond to the criteria of: a) organized production of goods or services; b) autonomy and independence; and c) democratic governance. Accordingly, because non‐profit organizations may be established for many purposes, only those which produce goods or services in an organized manner are part of the social economy. Considering that non‐profit organizations may be controlled by persons or entities which are not part of their membership, only those organizations which are not externally controlled are part of the social economy. Finally, because non‐profit organizations have no legal requirement regarding inspection, only those which may attest to the operation of their democratic processes of governance are part of the social economy. The conceptual framework is also used to create a typology, the purpose of which is to account for the differentiated economic dynamics of social economy organizations. Based on the capacity for hybridization of the resources which characterizes the social economy, the typology establishes six major types of organizations of the social economy according to the dominant mode of allocation of resources (commercial exchange, redistribution or reciprocity) and their main source (private or public). This typology is certainly insufficient to classify entities within the population but it is a complement to other existing classifications2. Adapting the conceptual framework to the specifics of Québec’s social economy allows taking into consideration entities which seem to be “exceptions” as far as the conceptual framework is concerned, because they do not correspond to the criteria of the logical model but nevertheless belong to the social economy “movement” of Québec. Some of these cases are analyzed in detail and are integrated to the Modèle logique opérationnel de l’économie sociale au Québec en 2011 [Logical Operational Model of the Social Economy in Québec in 2011], which repeats the steps of the general framework and takes the specifics of Québec into consideration. Finally, a case analysis of foundations shows the characteristics of those which would most likely be acknowledged as being part of the social economy if the Québec definition would eventually include them. If the conceptual framework should progress, this type of analysis may be repeated for other organizations or sectors of activity.Le cadre conceptuel pour définir la population statistique de l’économie sociale au Québec résulte d’une étude commandée par l’Institut de la statistique du Québec (ISQ), le ministère de l’Emploi et de la Solidarité sociale (MESS), le ministère de la Santé et des Services sociaux (MSSS) et le Secrétariat à l’action communautaire autonome et aux initiatives sociales (SACAIS). Le mandat a été confié à la Chaire de recherche du Canada en économie sociale de l’UQAM suite à un avis aux chercheurs se clôturant le 26 août 2010

A systematic review and meta-analysis of the reliability and validity of sensorimotor measurement instruments in people with chronic low back pain

Background: Deficits in the sensorimotor system and its peripheral and central processing of the affected body part might be a contributing factor to chronic low back pain (CLBP). Hence, sensorimotor assessment is important. Valid and reliable sensorimotor measurement instruments are needed. Objective: To investigate the reliability and validity of sensorimotor measurement instruments for people with chronic low back pain (CLBP). Design: Systematic review and meta-analysis. Methods: The review was undertaken using the COSMIN guidelines. Databases were searched for studies investigating the clinimetric properties of sensorimotor tests in people with CLBP. The methodological study quality was rated by two independent reviewers using the COSMIN 4-point rating checklist. Results: Ten studies were included covering six sensorimotor measurement instruments with findings for reliability/measurement error, known-groups validity and convergent validity. The methodological quality ranged from poor to good, with only one study rated as good. There was insufficient evidence of enough quality to assess reliability/measurement error or convergent validity. Two-point discrimination, laterality judgement and movement control tests had moderate evidence supporting their ability to distinguish between healthy people and those with CLBP. Conclusions: Two-point discrimination, laterality judgment and movement control tests demonstrate the greatest level of known-groups validity for people with CLBP. However, as the reliability of these measurement tools has yet to be established, this validity data should be interpreted cautiously. Further research is warranted to investigate the clinimetric properties of these sensorimotor techniques.</p

Spin noise and Bell inequalities in a realistic superconductor-quantum dot entangler

Charge and spin current correlations are analyzed in a source of spin-entangled electrons built from a superconductor and two quantum dots in parallel. In addition to the ideal (crossed Andreev) channel, parasitic channels (direct Andreev and cotunneling) and spin flip processes are fully described in a density matrix framework. The way they reduce both the efficiency and the fidelity of the entangler is quantitatively described by analyzing the zero-frequency noise correlations of charge current as well as spin current in the two output branches. Spin current noise is characterized by a spin Fano factor, equal to 0 (total current noise) and -1 (crossed correlations) for an ideal entangler. The violation of the Bell inequalities, as a test of non-locality (entanglement) of split pairs, is formulated in terms of the correlations of electron charge and spin numbers counted in a specific time window $\tau$. The efficiency of the test is analyzed, comparing $\tau$ to the various time scales in the entangler operation.Comment: 8 pages, 5 figures, references added, to appear in Phys. Rev.

NASA Space applications of high-temperature superconductors

The application of superconducting technology in space has been limited by the requirement of cooling to near liquid helium temperatures. The only means of obtaining these temperatures has been with cryogenic fluids which severely limit mission lifetime. The development of materials with superconducting transition temperatures above 77 K has made superconducting technology more attractive and feasible for employment in aerospace systems. Here, potential applications of high temperature superconducting technology in cryocoolers, remote sensing, communications, and power systems are discussed

A comparison between quantum chemistry and quantum Monte Carlo techniques for the adsorption of water on the (001) LiH surface

We present a comprehensive benchmark study of the adsorption energy of a single water molecule on the (001) LiH surface using periodic coupled cluster and quantum Monte Carlo theories. We benchmark and compare different implementations of quantum chemical wave function based theories in order to verify the reliability of the predicted adsorption energies and the employed approximations. Furthermore we compare the predicted adsorption energies to those obtained employing widely-used van der Waals density-functionals. Our findings show that quantum chemical approaches are becoming a robust and reliable tool for condensed phase electronic structure calculations, providing an additional tool that can also help in potentially improving currently available van der Waals density-functionals

Theory of the ac spin-valve effect

The spin-valve complex magnetoimpedance of symmetric ferromagnet/normal metal/ferromagnet junctions is investigated within the drift-diffusion (standard) model of spin injection. The ac magnetoresistance---the real part difference of the impedances of the parallel and antiparallel magnetization configurations---exhibits an overall damped oscillatory behavior, as an interplay of the diffusion and spin relaxation times. In wide junctions the ac magnetoresistance oscillates between positive and negative values, reflecting resonant amplification and depletion of the spin accumulation, while the line shape for thin tunnel junctions is predicted to be purely Lorentzian. The ac spin-valve effect could be a technique to extract spin transport and spin relaxation parameters in the absence of a magnetic field and for a fixed sample size.Comment: 5 pages, 4 figure