4,993 research outputs found

    School reform, school size, and student achievement

    Get PDF
    An estimation of the effect of school size on student achievement, with the results suggesting that market-based school reform could enhance student performance if the reform reduced school size.Education

    Hepatoma cell density promotes claudin-1 and scavenger receptor BI expression and hepatitis C virus internalization.

    Get PDF
    Hepatitis C virus (HCV) entry occurs via a pH- and clathrin-dependent endocytic pathway and requires a number of cellular factors, including CD81, the tight-junction proteins claudin 1 (CLDN1) and occludin, and scavenger receptor class B member I (SR-BI). HCV tropism is restricted to the liver, where hepatocytes are tightly packed. Here, we demonstrate that SR-BI and CLDN1 expression is modulated in confluent human hepatoma cells, with both receptors being enriched at cell-cell junctions. Cellular contact increased HCV pseudoparticle (HCVpp) and HCV particle (HCVcc) infection and accelerated the internalization of cell-bound HCVcc, suggesting that the cell contact modulation of receptor levels may facilitate the assembly of receptor complexes required for virus internalization. CLDN1 overexpression in subconfluent cells was unable to recapitulate this effect, whereas increased SR-BI expression enhanced HCVpp entry and HCVcc internalization, demonstrating a rate-limiting role for SR-BI in HCV internalization

    Hybrid copula mixed models for combining case-control and cohort studies in meta-analysis of diagnostic tests

    Get PDF
    Copula mixed models for trivariate (or bivariate) meta-analysis of diagnostic test accuracy studies accounting (or not) for disease prevalence have been proposed in the biostatistics literature to synthesize information. However, many systematic reviews often include case-control and cohort studies, so one can either focus on the bivariate meta-analysis of the case-control studies or the trivariate meta-analysis of the cohort studies, as only the latter contains information on disease prevalence. In order to remedy this situation of wasting data we propose a hybrid copula mixed model via a combination of the bivariate and trivariate copula mixed model for the data from the case-control studies and cohort studies, respectively. Hence, this hybrid model can account for study design and also due to its generality can deal with dependence in the joint tails. We apply the proposed hybrid copula mixed model to a review of the performance of contemporary diagnostic imaging modalities for detecting metastases in patients with melanoma

    Intermediate Tail Dependence: A Review and Some New Results

    Full text link
    The concept of intermediate tail dependence is useful if one wants to quantify the degree of positive dependence in the tails when there is no strong evidence of presence of the usual tail dependence. We first review existing studies on intermediate tail dependence, and then we report new results to supplement the review. Intermediate tail dependence for elliptical, extreme value and Archimedean copulas are reviewed and further studied, respectively. For Archimedean copulas, we not only consider the frailty model but also the recently studied scale mixture model; for the latter, conditions leading to upper intermediate tail dependence are presented, and it provides a useful way to simulate copulas with desirable intermediate tail dependence structures.Comment: 25 pages, 1 figur

    Factor copula models for item response data

    Get PDF
    Factor or conditional independence models based on copulas are proposed for multivariate discrete data such as item responses. The factor copula models have interpretations of latent maxima/minima (in comparison with latent means) and can lead to more probability in the joint upper or lower tail compared with factor models based on the discretized multivariate normal distribution (or multidimensional normal ogive model). Details on maximum likelihood estimation of parameters for the factor copula model are given, as well as analysis of the behavior of the log-likelihood. Our general methodology is illustrated with several item response data sets, and it is shown that there is a substantial improvement on existing models both conceptually and in fit to data

    Development of a Polythene Recycling Machine from Locally Sourced Materials

    Get PDF
    Non-biodegradable polythene and nylon wastes constitute a nuisance in all the urban areas in Nigeria. The paper presents the design and manufacture of a waste-recycling machine to convert these waste materials to reusable materials. The machine uses designed to use fixed and rotary blades for slitting the loaded wastes. The rotary blades are rotated by a single phase, high speed electric motor and the friction generated provides the heat required to soften the waste charges. The recycling machine produces an average of 35kg of small flakes of recycled waste per hour at a machine speed of 2880 rpm. Keywords: Polythene, Nylon, Biodegradable, Waste Recycling, Electric Moto

    Developing the public health function of locum pharmacists under the auspices of the new pharmacy contract

    Get PDF
    Focal Point - There are reduced opportunities for locum pharmacists to access training and education that meets their needs and enables them to play a full role under the new pharmacy contract - Eighty-six per cent of locums consider themselves to be more health professional than business person, compared to just 48% of pharmacy owners - Forty per cent of locums believe that a lack of access to training is a major barrier to the development of their public health function - While locum pharmacists are arguably more likely to embrace 'professionalising', patient-care-based roles, they are also the group least likely to be able to access the necessary training to fulfill such roles Introduction It has been suggested that locum pharmacists do not want the business-based responsibilities (e.g. staff management, meeting targets, etc) that come with pharmacy management.1 Research also suggests that locums derive great satisfaction from the health-professional aspects of the pharmacists’ role (e.g. patient contact, the provision of advice, etc).1 However, upon the introduction of the new pharmacy contract (April 2005), concerns were expressed that it was becoming increasingly difficult for locum pharmacists to access training and education that would meet their needs and enable them to play a full role under the new framework.2,3 Method After piloting, in August 2006 a self-completion postal questionnaire was sent to a random sample of practising community pharmacists, stratified for country and sex, within Great Britain (n = 1998), with a follow-up to non-responders 4 weeks later. Data were analysed using SPSS (v12.0). A final response rate of 51% (n = 1023/1998) was achieved. Respondents were asked ‘indicate how you view yourself as a pharmacist’ – in terms of their relative focus on the health-professional and business aspects of their role. Respondents were also asked ‘do you consider a lack of training opportunities to be a barrier to the development of the public health role of community pharmacists?’. Results Locums were significantly more likely than owners or employees to consider each factor a major barrier. Discussion Four in 10 locums consider a lack of training opportunities to constitute a major barrier to the development of their public health function. Pharmacy may not be able to provide the services required of it by the policy agenda if pharmacists are unable to be involved in extended role activities through a lack of training opportunities. Therefore, the paradox that needs to be addressed is that while locum pharmacists are arguably more likely to embrace ‘professionalising’, patient-care-based roles, they are also the group least likely to be able to access training to fulfil such roles. The training needs of this large subset of the pharmacist population need to be assessed and met if the whole community pharmacy workforce is going to maximise its contribution to public health under the new contractual framework. References 1 Shann P, Hassell K. An exploration of the diversity and complexity of the pharmacy locum workforce. London: Royal Pharmaceutical Society of Great Britain; 2004. 2 Almond M. Locums – key players in workforce – cast adrift as contract launched. Pharm J 2005;274:420. 3 Bishop DH. A lack of appreciation of what really happens. Pharm J 2005;274:451

    Community pharmacy in a commissioning-led NHS:can pharmacy compete effectively?

    Get PDF
    Introduction – The commissioning of services has been a core responsibility of English Primary Care Trusts (PCTs) since 2002. Primary care organisations (PCOs) in Scotland, Wales and Northern Ireland have also increased their commissioning activities but with, arguably, less fervour than their English counterparts. The commissioning function of English PCTs has been reinforced by the introduction of new contractual frameworks across primary care – for medical services, dentistry and pharmacy. The new pharmaceutical services contract for England and Wales introduced an “enhanced” category of services, the provision of which is dependent on the commissioning decisions of local PCTs. As the NHS, most pertinently in England, continues its transformation from a provider to a commissioner of healthcare, the ability of pharmacy to compete effectively for funding is likely to become increasingly important. Method - After piloting, in August 2006 a self-completion postal questionnaire was sent to a random sample of practising community pharmacists, stratified for country and sex, within Great Britain (n=1998), with a follow-up to non-responders 4 weeks later. Data were analysed using SPSS (v12.0). A final response rate of 51% (n=1023/1998) was achieved. Within the section of the questionnaire relating to service provision, respondents were asked “do you believe that pharmacy will be able to compete effectively with other healthcare providers for access to additional funding to develop services that address a public health need identified by your local Primary Care Organisation (PCO), e.g. PCT/LHB etc.?”. Answers were recorded on a three-point scale; pharmacy “will”, “may”, or “will not” be able to compete effectively for funding. Results - The attitudes of pharmacists showed variation depending on the type of pharmacy they worked in (supermarket, multiple (outlets (n)=200), large chain (200>n>20), small chain (20=n>5), or independent (n=5)) (?2 test with p=0.001). Over a third of survey pharmacists working in small chains and independents (37% (n=21/57) and 33% (n=113/341) respectively) believed that pharmacy would not be able to compete effectively for funding compared to 23% (n=15/65) for supermarket pharmacists, 22% (n=21/97) for pharmacists employed by large chains and just 18% (n=62/353) for pharmacists employed most regularly in multiples. Furthermore, attitudes also varied between the countries of residence of respondents (?2 test with p<0.05). 27% (n=242/893) of pharmacists resident in England and Wales believed that pharmacy would not be able to compete compared to 16% (n=18/116) of pharmacists resident in Scotland. Conclusions – It would appear that community pharmacists believe that the larger pharmacy chains and supermarkets will occupy an advantageous position in terms of attracting finance to develop services. This could have notable implications for service provision across the sector. If corporate pharmacy chains were to monopolise commissioning monies then the proportion of funding available to independents will be diminished; arguably further hastening their demise, as well as stifling the professional development of pharmacists employed within the independent sector. These findings, when combined with the variation observed between UK pharmacists operating under different contractual frameworks, may be a reflection of the divergent policy in the different administrations with developments in England, including the new pharmacy contract, reflecting a market-based approach with Scotland taking a near opposite stance with service integration and a commitment to new public health. However, it should be acknowledged that the questionnaire did not allow for detection of ambiguities in, or misunderstandings of, the survey question and this should be considered as a limitation of the research
    corecore