Socially (un)acceptable

Access to social media sites via public libraries is patchy in Scotland, says Christine Rooney-Browne, and it’s time to bring them all into the world of shared communities

Data management in engineering

An introduction to computer based data management is presented with an orientation toward the needs of engineering application. The characteristics and structure of data management systems are discussed. A link to familiar engineering applications of computing is established through a discussion of data structure and data access procedures. An example data management system for a hypothetical engineering application is presented

Blogging: an opportunity for librarians to communicate, participate and collaborate on a global scale

Blogs are an important element of the second generation of the web; or ‘Web 2.0’ as it is commonly referred to. ‘Web 2.0’ refers to the evolution from static "read only" web pages (Web 1.0) to dynamic, interactive pages encouraging users to create, interact and share content across multiple applications (O’Reilly, 2005). Blogging, along with other Web 2.0 technologies such as social networking, wikis, social bookmarking, photo sharing, video sharing, and microblogging, form part of the emergent ‘social media’ family; a collection of online tools that encourage users to communicate, participate, and collaborate on a global scale. Many library and information professionals have embraced blogging as a platform to document their career, enhance their profile, network with other librarians; and share anecdotes about their lives as librarians. The aim of this article is to present a brief overview of the history of blogs and a short review of literature related to blogging, libraries and reference librarians. It will also provide a list of recommended blogs, a discussion of the advantages of reading and writing blogs and some top tips for starting up your own blog

Performance of the resurfaced hip. Part 1: the influence of the prosthesis size and positioning on the remodelling and fracture of the femoral neck

Hip resurfacing is an established treatment for osteoarthritis in young active patients. Failure modes include femoral neck fracture and prosthesis loosening, which may be associated with medium-term bone adaptation, including femoral neck narrowing and densification around the prosthesis stem.Finite element modelling was used to indicate the effects of prosthesis sizing and positioning on the bone remodelling and fracture strength under a range of normal and traumatic loads, with the aim of understanding these failure modes better.The simulations predicted increased superior femoral neck stress shielding in young patients with small prostheses, which required shortening of the femoral neck to give an acceptable implant–bone interface. However, with a larger prosthesis, natural femoral head centre recreation in the implanted state was possible; therefore stress shielding was restricted to the prosthesis interior, and its extent was less sensitive to prosthesis orientation. With valgus orientation, the implanted neck strength was, at worst, within 3 per cent of its intact strength.The study suggests that femoral neck narrowing may be linked to a reduction in the horizontal femoral offset, occurring if the prosthesis is excessively undersized. As such, hip resurfacing should aim to reproduce the natural femoral head centre, and, for valgus prosthesis orientation, to avoid femoral neck fracture

The lone parent pilots after 12 to 24 months: an impact assessment of in-work credit, work search premium, extended schools childcare, quarterly work focused interviews and new deal plus for lone parents

From April 2004, a set of Government policies designed to help lone parents into work have been piloted in various combinations in a number of Jobcentre Plus districts in Great Britain. The five policies are: In Work Credit (IWC), Work Search Premium (WSP), Extended Schools Childcare (ESC) and Childcare Tasters, Quarterly Work Focused Interviews (QWFIs) for lone parents whose youngest child is aged 12 or over in Local Education Authorities (LEAs) in which an ESC pilot is operating (ESQWFI), and New Deal Plus for Lone Parents (ND+fLP), hereafter collectively referred to as 'the lone parent pilots' (LPPs or 'the pilots'). The pilots were rolled out in four Phases, the first three of which are analysed in this report. This report estimates the impact of the LPPs on lone parents who have received Income Support (IS) or Jobseeker's Allowance (JSA) for at least 12 months. It uses a difference-in-differences (DiD) estimator, and makes use of lone parents in districts not operating a pilot as a comparison group. The data covers the first 12 months (Phase 3 districts) to the first 24 months (Phase 1 districts) of the pilots' operation, and so should be seen as giving the early impacts. Impacts were estimated separately for the stock of lone parents who had been on benefit for at least 12 months when the pilots began, and the flow sample of lone parents whose claim of IS/JSA reached 12 months after the pilots began

Mind the gap! A multilevel analysis of factors related to variation in published cost-effectiveness estimates within and between countries

Background. Published cost-effectiveness estimates can vary considerably, both within and between countries. Despite extensive discussion, little is known empirically about factors relating to these variations. Objectives. To use multilevel statistical modeling to integrate cost-effectiveness estimates from published economic evaluations to investigate potential causes of variation. Methods. Cost-effectiveness studies of statins for cardiovascular disease prevention were identified by systematic review. Estimates of incremental costs and effects were extracted from reported base case, sensitivity, and subgroup analyses, with estimates grouped in studies and in countries. Three bivariate models were developed: a cross-classified model to accommodate data from multinational studies, a hierarchical model with multinational data allocated to a single category at country level, and a hierarchical model excluding multinational data. Covariates at different levels were drawn from a long list of factors suggested in the literature. Results. We found 67 studies reporting 2094 cost-effectiveness estimates relating to 23 countries (6 studies reporting for more than 1 country). Data and study-level covariates included patient characteristics, intervention and comparator cost, and some study methods (e.g., discount rates and time horizon). After adjusting for these factors, the proportion of variation attributable to countries was negligible in the cross-classified model but moderate in the hierarchical models (14%−19% of total variance). Country-level variables that improved the fit of the hierarchical models included measures of income and health care finance, health care resources, and population risks. Conclusions. Our analysis suggested that variability in published cost-effectiveness estimates is related more to differences in study methods than to differences in national context. Multinational studies were associated with much lower country-level variation than single-country studies. These findings are for a single clinical question and may be atypical

Mixtures of Shifted Asymmetric Laplace Distributions

A mixture of shifted asymmetric Laplace distributions is introduced and used for clustering and classification. A variant of the EM algorithm is developed for parameter estimation by exploiting the relationship with the general inverse Gaussian distribution. This approach is mathematically elegant and relatively computationally straightforward. Our novel mixture modelling approach is demonstrated on both simulated and real data to illustrate clustering and classification applications. In these analyses, our mixture of shifted asymmetric Laplace distributions performs favourably when compared to the popular Gaussian approach. This work, which marks an important step in the non-Gaussian model-based clustering and classification direction, concludes with discussion as well as suggestions for future work

Unsupervised Learning via Mixtures of Skewed Distributions with Hypercube Contours

Mixture models whose components have skewed hypercube contours are developed via a generalization of the multivariate shifted asymmetric Laplace density. Specifically, we develop mixtures of multiple scaled shifted asymmetric Laplace distributions. The component densities have two unique features: they include a multivariate weight function, and the marginal distributions are also asymmetric Laplace. We use these mixtures of multiple scaled shifted asymmetric Laplace distributions for clustering applications, but they could equally well be used in the supervised or semi-supervised paradigms. The expectation-maximization algorithm is used for parameter estimation and the Bayesian information criterion is used for model selection. Simulated and real data sets are used to illustrate the approach and, in some cases, to visualize the skewed hypercube structure of the components