2,923 research outputs found

    A systematic review of changes in womenā€™s physical activity before and during pregnancy and the postnatal period

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    Objectives: To determine the magnitude and type of naturally occuring physical activity changes in women around the time of pregnancy. Background: This systematic review synthesises the results of studies examining naturally occurring physical activity in women before they become pregnant and the magnitude and type of changes during pregnancy and the postnatal period. Methods: Electronic databases were searched for relevant articles and PRISMA guidelines for selection of articles were used. Only studies examining naturally occurring, non-intervention changes in regular activity levels were included. The quality assessment was based on protocols of the Cochrane Database of Systematic Reviews. Of the initial 720 titles, 24 studies met the inclusion criteria and were included in the final review. Results: Compared to pre-pregnancy, the magnitude of physical activity decreased over the course of pregnancy and postnatally and the types of activities tended to be of lesser intensity than pre-pregnancy. The quality of the research was varied; methodological limitations included using subjective methods of assessment of physical activity (9/24), failing to report reliabilities or validity of measures used (8/24), no information on parity (13/24) or level of fitness prior to pregnancy (11/24). Conclusion: The evidence suggests a marked decrease in the amount and type of moderate to strenuous physical activity during the transition to motherhood, which does not always increase again postpartum. Patient education targeting specific physical activities at regular intervals during and after pregnancy to improve long-term maternal health is necessary

    Optimal Distributed Power Generation Under Network-Load Constraints

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    In electrical power networks nowadays more and more customers are becoming power-producers, mainly because of the development of novel components for decentralized power generation (solar panels, small wind turbines and heat pumps). This gives rise to the question how many units of each type (solar panel, small wind turbine or central heating power units) can be inserted into any transmission line in the network, such that under given distributions on the typical production and consumption over time, the maximum loads on the lines and components will not be exceeded. In this paper, we present a linear programming model for maximizing the amount of decentralized power generation while respecting the load limitations of the network. We describe a prototype showing that for an example network the maximization problem can be solved efficiently. We also modeled the case were the power consumption and decentralized power generation are considered as stochastic variables, which is inherently more complex

    Routing for analog chip designs at NXP Semiconductors

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    During the study week 2011 we worked on the question of how to automate certain aspects of the design of analog chips. Here we focused on the task of connecting different blocks with electrical wiring, which is particularly tedious to do by hand. For digital chips there is a wealth of research available for this, as in this situation the amount of blocks makes it hopeless to do the design by hand. Hence, we set our task to finding solutions that are based on the previous research, as well as being tailored to the specific setting given by NXP. This resulted in an heuristic approach, which we presented at the end of the week in the form of a protoype tool. In this report we give a detailed account of the ideas we used, and describe possibilities to extend the approach

    A Class of Simple Distribution-free Rank-based Unit Root Tests (Revision of DP 2010-72)

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    We propose a class of distribution-free rank-based tests for the null hypothesis of a unit root. This class is indexed by the choice of a reference density g, which needs not coincide with the unknown actual innovation density f. The validity of these tests, in terms of exact finite sample size, is guaranteed, irrespective of the actual underlying density, by distribution-freeness. Those tests are locally and asymptotically optimal under a particular asymptotic scheme, for which we provide a complete analysis of asymptotic relative efficiencies. Rather than asymptotic optimality, however, we emphasize finitesample performances. Finite-sample performances of unit root tests, however, depend quite heavily on initial values. We therefore investigate those performances as a function of initial values. It appears that our rank-based tests significantly outperform the traditional Dickey-Fuller tests, as well as the more recent procedures proposed by Elliot, Rothenberg, and Stock (1996), Ng and Perron (2001), and Elliott and MĀØuller (2006), for a broad range of initial values and for heavy-tailed innovation densities. As such, they provide a useful complement to existing techniques.Unit root;Dickey-Fuller test;Local Asymptotic Normality;Rank test

    The asymptotic structure of nearly unstable non-negative integer-valued AR(1) models

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    This paper considers non-negative integer-valued autoregressive processes where the autoregression parameter is close to unity. We consider the asymptotics of this `near unit root' situation. The local asymptotic structure of the likelihood ratios of the model is obtained, showing that the limit experiment is Poissonian. To illustrate the statistical consequences we discuss efficient estimation of the autoregression parameter and efficient testing for a unit root.Comment: Published in at http://dx.doi.org/10.3150/08-BEJ153 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    The changing profile of surrogacy in the UK ā€“ implications for national and international policy and practice

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    Since 2007, the numbers of UK Parental Orders granted following surrogacy have markedly increased. More recently, eligibility criteria have been extended to unmarried heterosexual couples and same-sex couples rather than only married couples. Numbers seeking fertility treatments, including through surrogates, outside their country of residence have also increased. This paper presents the limited data currently available ā€“ from UK General Register Offices, Child and Family Court Advisory and Support Service for England and the UK surrogacy agencies: COTS, Surrogacy UK, British Surrogacy Centre ā€“ to consider potential reasons for the increase and to consider policy and practice implications. It charts the apparent decline in involvement of surrogacy agencies and suggests the potential for exploitation where scrutiny of arrangements and follow up are limited. It recommends improvements to data collection and argues the need for a more integrated approach to review of surrogacy arrangements both nationally and internationally

    UnitingCare West Pathways

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    This evaluation report explores and reports on the effectiveness of the Pathways program, delivered by UnitingCare West (UCW) in Perth, Western Australia. UCW is a strong advocate for people who are most in need, including homeless people with complex needs and those at risk of homelessness..

    "Wenn ich alle Pillen genommen habe, bin ich satt" : MultimorbiditƤt und Multimedikation: Herausforderungen in einer alternden Gesellschaft

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    Mit den Krankheiten hƤuft sich im Alter auch die Zahl der einzunehmenden Medikamente. Das bringt viele Probleme mit sich. Das Institut fĆ¼r Allgemeinmedizin der Goethe-UniversitƤt untersucht in enger Kooperation mit der UniversitƤt Maastricht die Folgen der Multimedikation und entwickelt gemeinsam mit HausƤrzten Strategien, um unerwĆ¼nschte Wirkungen zu vermeiden

    Simulation of emotions of agents in virtual environments using neural networks

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    A distributed architecture for a system simulating the emotional state of an agent acting in a virtual environment is presented. The system is an implementation of an event appraisal model of emotional behaviour and uses neural networks to learn how the emotional state should be influenced by the occurrence of environmental and internal\ud stimuli. A part of the modular system is domain-independent. The system can easily be adapted for handling different events that influence the emotional state. A first\ud prototype and a testbed for this architecture are presented

    The extent, variability, and attitudes towards volunteering among undergraduate nursing students: implications for pedagogy in nurse education

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    In the aftermath of the Francis Report nurses are being called to account for an apparent lack of care and compassion, leading to debate around pedagogy in nurse education. Absent from this debate is a consideration of student volunteering within undergraduate nursing programmes and its potential to promote student nurses self-esteem and to enhance the development of critical thinking skills. The aim of this study was therefore to understand the extent of and attitudes towards volunteering among nursing students. A mixed methods approach using a specifically developed questionnaire, followed by in-depth interviews to ascertain extent, variability, and attitudes towards volunteering revealed low levels of volunteering among nursing students. Limited time, limited access, and lack of academic support were cited as reasons. Nevertheless, students displayed positive attitudes towards volunteering. While volunteering has been shown to impact upon students abilities to think critically, to develop personal values and respond to the needs of others, volunteering within the UK undergraduate nursing programme considered is neither structured nor formalized. Nurse educators should pay attention to the positive benefits of volunteering for nursing students and consider ways in which volunteering might be incorporated into the curriculum
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