Estimating spillovers using imprecisely measured networks

In many experimental contexts, whether and how network interactions impact the outcome of interest for both treated and untreated individuals are key concerns. Networks data is often assumed to perfectly represent these possible interactions. This paper considers the problem of estimating treatment effects when measured connections are, instead, a noisy representation of the true spillover pathways. We show that existing methods, using the potential outcomes framework, yield biased estimators in the presence of this mismeasurement. We develop a new method, using a class of mixture models, that can account for missing connections and discuss its estimation via the Expectation-Maximization algorithm. We check our method's performance by simulating experiments on real network data from 43 villages in India. Finally, we use data from a previously published study to show that estimates using our method are more robust to the choice of network measure

Objectively measured physical capability levels and mortality: systematic review and meta-analysis

Objective: To do a quantitative systematic review, including published and unpublished data, examining the associations between individual objective measures of physical capability (grip strength, walking speed, chair rising, and standing balance times) and mortality in community dwelling populations. Design: Systematic review and meta-analysis. Data sources: Relevant studies published by May 2009 identified through literature searches using Embase (from 1980) and Medline (from 1950) and manual searching of reference lists; unpublished results were obtained from study investigators. Study selection: Eligible observational studies were those done in community dwelling people of any age that examined the association of at least one of the specified measures of physical capability (grip strength, walking speed, chair rises, or standing balance) with mortality. Data synthesis: Effect estimates obtained were pooled by using random effects meta-analysis models with heterogeneity between studies investigated. Results: Although heterogeneity was detected, consistent evidence was found of associations between all four measures of physical capability and mortality; those people who performed less well in these tests were found to be at higher risk of all cause mortality. For example, the summary hazard ratio for mortality comparing the weakest with the strongest quarter of grip strength (14 studies, 53 476 participants) was 1.67 (95% confidence interval 1.45 to 1.93) after adjustment for age, sex, and body size (I2=84.0%, 95% confidence interval 74% to 90%; P from Q statistic <0.001). The summary hazard ratio for mortality comparing the slowest with the fastest quarter of walking speed (five studies, 14 692 participants) was 2.87 (2.22 to 3.72) (I2=25.2%, 0% to 70%; P=0.25) after similar adjustments. Whereas studies of the associations of walking speed, chair rising, and standing balance with mortality have only been done in older populations (average age over 70 years), the association of grip strength with mortality was also found in younger populations (five studies had an average age under 60 years). Conclusions: Objective measures of physical capability are predictors of all cause mortality in older community dwelling populations. Such measures may therefore provide useful tools for identifying older people at higher risk of death. With Contributions from Dr P.A. Bath, University of Sheffiel

Modalités de socialisation et représentations didactiques de maîtres de l’enseignement professionnel au Québec

Cet article présente le cadre d'analyse et la méthodologie d'une recherche qu'allie une approche didactique à une perspective sociologique retenus pour étudier les représentations des enseignants qui oeuvrent auprès d'élèves postulant un diplôme d'études professionnelles (DEP) en secrétariat ou en usinage. Il traite ensuite des caractéristiques socioprofessionnelles des enseignants et de leurs modalités de socialisation en scrutant la représentation des types de savoir qu'ils relient au métier enseigné et au monde du travail, et leur représentation de leurs élèves et de leur rôle vis-à-vis d'eux. Ces représentations valorisent le savoir-être centré sur les capacités de participation au milieu de travail. L'étude des représentations didactiques met en évidence la cohabitation des orientations humaniste et cognitiviste chez les maîtres de l'enseignement professionnel. Les observations sociologiques et didactiques révèlent une même préoccupation des enseignants devant les changements du milieu de travail et le développement des aptitudes de leurs élèves à participer et à s'adapter à ces changements.This article presents the analytic frame and the methodology related to a didactic approach within a sociological perspective which was used to analyze teachers' reprensentations. These teachers work with students enrolled in a diploma program of professional studies (DEP) in machinery or in secretarial services. The authors describe the socio-professional characteristics of these teachers and their methods for developing socialization processes. These processes are examined from information about teachers' representations of the types of knowledge related to content area taught and to the workplace, as well as teachers' perception of their students and of their own role towards students. The analysis shows that teachers promote social skills, specifically those related to developing capacities to participate more fully in the workplace. The study of didactic representations shows the presence of both humanistic and cognitive objectives. Observations from both sociological and didactic perspectives show that teachers are preoccupied with the need to develop students' participatory skills as well as their abilities to adapt to a changing workplace environment.Este artfculo présenta el marco de anâlisis y la metodologia de un enfoque didàctico aliado a una perspectiva sociolôgica para analizar las representaciones de maestros que trabajan con alumnos inscritos en un diploma de estudios profesionales en secretariado o en fabricacion industrial. A continuaciôn se discuten las caracteristicas socioprofesionales de los maestros y sus modalidades de socialization, a través del estudio de la representation de tipos de conocimientos que ellos relacionan con la profesion docente y con el medio de trabajo, asi como del estudio de sus representaciones de sus propios alumnos y de sus relaciones con ellos. Estas representaciones valorizan el saber-ser centrado en la capacidad de participacion en el medio de trabajo. El estudio de las representaciones didàcticas pone en evidencia la cohabitacion de las orientaciones humanista y cognoscitiva en los maestros de ensenanza profesional. Las observaciones sociologicas y didàcticas revelan una misma preocupaciôn de los maestros frente a los cambios en el medio de trabajo y al desarrollo de aptitudes de sus alumnos para participar y adaptarse a estos cambios.Dieser Artikel stellt den Rahmen und die Methodik einer soziologisch orientierten didaktischen Erforschung der Auffassungen von Lehrern dar, die mit Schiilern arbeiten, die ein Fachschuldiplom (DEP) als Sekretârln oder als Maschinistln anstreben. Er behandelt anschlietèend das sozialberufliche Profil der Lehrer und deren Sozialisierungs- modalitàten, wobei untersucht wird, wie die Typen der Kenntnisse betrachtet werden, die sie mit dem gelehrten Beruf und mit der Arbeit verbinden, und wie sie die Schiller und deren Rolle ihnen gegeniiber sehen. Dièse Auffassungen valorisieren die personengebunde Gewandtheit, vor allem aber die Fàhigkeit, am Arbeitsmilieu teilzuhaben. Die Analyse der didaktischen Auffassungen bringt dieTatsache in den Vordergrund, daf? die humanistische und die kognitivistische Richtungen bei den Fachschullehrern gleichermafSen vertreten sind. Bei der soziologischen und didaktischen Untersuchung kommt zum Vorschein, daf? sich die Lehrer sehr mit dem Umstand befassen, daf? das Arbeitsmilieu sich veràndert und ihre Schiller neue Fàhigkeiten entwickeln miissen, um mit diesen Verànderungen fertigzuwerden

Developing a model for e-prints and open access journal content in UK further and higher education

A study carried out for the UK Joint Information Systems Committee examined models for the provision of access to material in institutional and subject-based archives and in open access journals. Their relative merits were considered, addressing not only technical concerns but also how e-print provision (by authors) can be achieved – an essential factor for an effective e-print delivery service (for users). A "harvesting" model is recommended, where the metadata of articles deposited in distributed archives are harvested, stored and enhanced by a national service. This model has major advantages over the alternatives of a national centralized service or a completely decentralized one. Options for the implementation of a service based on the harvesting model are presented

Space Resource Technologies

This is a very general presentation being given to students about Swamp Works and what kind of work we do here. It contains images of our labs, an overview of the four labs' areas of focus, and several sample projects that revolve around developing ISRU (in-situ resource utilization) capabilities - living off the land in space - such as mining robots and sampling devices

PELICAN - Pricing Experiment Library Information Co-operative Network: final report

In recognition of the complexity of the research field, the Pelican project aims to address strategic, methodological and practical issues. The Pelican project aims to assess current practices in electronic delivery of text to students and establish existing usage patterns. It will identify models most likely to be acceptable to students, HEIs, publishers, authors and the CLA. It will act as a facilitator to provide a communication network for the development of a suitable pricing mechanism and recognise the diverse interest of all stakeholders involved in the HE/FE community. On project completion, Pelican will recommend areas for further work. The project is under the direction of Loughborough University who will work closely with its partners, Stirling University and an Independent Consultant. Pelican was developed in response to JISC Circular 5/99. It covers elements of §46 (extending the range and effectiveness of JISC projects, which are developing into services), §47 (more general proposals for extending the usefulness of JISC services in ways not specifically covered) and §71 (digital library service development). Pelican will assist the learning activities of HEIs in a number of ways: through the leadership of Loughborough, it will build on the experience and confidence building of the JISC/PA Working Parties to help develop mutually acceptable ways of charging for distributing digitised materials to students; through the participation of Stirling, which plays a leading role in HERON, close co-operation with HERON will be maintained; through an active evaluation and dissemination programme, HEIs will gain a better understanding of the issues involved, and will thus be able to plan their own provision with more confidence. The combination of these factors will lead to an environment whereby electronic texts may be delivered to students in HEIs in an efficient and acceptable manner, whilst at the same time ensuring an adequate return to the rights’ owners

Digitised content in the UK research library and archives sector

A study of the current provision of digitised collections for researchers in the UK higher education sector was carried out through desk research, a Webbased questionnaire of research libraries and interviews. The study identified a great deal of digitised material in the sector and there has been considerable expenditure of UK public funds in the creation of digital material in the last ten years. However, funding of digitisation been piecemeal and uncoordinated. It is clear that there is a need for coordination, but no agreement on how it should be implemented. Any future national approach would have to be a co-ordinated and distributed, rather than centralised, one

Digitised content in the UK research library and archives sector

In August 2004, the JISC and CURL Digital Content Creation & Curation Task Force issued an invitation to tender for a study of the current provision of digitised collections for researchers in the UK higher education sector. The objectives of this study were to: 1) Produce a high level survey of digitised material, both already available and in the process of being created, held in UK research collections across all disciplines 2) Survey demand for digitised material and identify gaps in existing provision 3) Develop a mechanism for identifying future digitisation priorities 4) Review funding structures and opportunities and assess possible ways of funding priority areas 5) Recommend standards and formats for future digitisation projects 6) Provide an outline action plan for a national digitisation strategy for the UK research community. JISC and CURL commissioned a team of researchers from the Department of Information Science at Loughborough University to carry out this survey. The study was carried out between 1 November 2004 and 7 March 2005

Comparison of the EPIC Physical Activity Questionnaire with combined heart rate and movement sensing in a nationally representative sample of older British adults

Peer reviewedPublisher PD

Verbal memory and search speed in early midlife are associated with mortality over 25 years’ follow-up, independently of health status and early life factors: a British birth cohort study

Background: Cognitive capabilities in childhood and in late life are inversely associated with mortality rates. However it is unclear if adult cognition, at a time still relatively free from comorbidity, is associated with subsequent mortality, and if this explains the associations of early life factors on adult mortality. Methods: We used data from the MRC National Survey of Health and Development, a birth cohort study prospectively assessing 5362 participants born in 1946. The present analysis includes participants followed-up from age 43 and undergoing cognitive assessment (verbal memory and search speed). Mortality outcomes were notified through linkage with a national register. Cox regression was used to estimate mortality hazards in relation to cognitive performance at age 43, adjusting for early life factors, socio-economic position and health status. Results: Data were available on 3192 individuals. Univariable analyses indicated that adult verbal memory and search speed, parental factors, childhood cognition and educational attainment were associated with mortality. However, multivariable models showed the mortality associations with earlier life factors were explained by adult cognitive capability. A standard deviation increase in verbal memory and search speed scores was associated with lower mortality rates (HR=0.86, 95%CI 0.77-0.97, p=0.02; HR=0.88, 95%CI 0.78-1.00, p=0.05, respectively), after adjustment for adult health. Conclusions: Cognitive capability in early midlife was inversely associated with mortality rates over 25 years and accounted for the associations of family background, childhood cognitive ability and educational attainment with mortality. These findings, in a nationally representative cohort with long-term follow-up, suggest that building cognitive reserve may improve later life health and survival chances