Rediscovering a little known fact about the t-test and the F-test: Algebraic, Geometric, Distributional and Graphical Considerations

We discuss the role that the null hypothesis should play in the construction of a test statistic used to make a decision about that hypothesis. To construct the test statistic for a point null hypothesis about a binomial proportion, a common recommendation is to act as if the null hypothesis is true. We argue that, on the surface, the one-sample t-test of a point null hypothesis about a Gaussian population mean does not appear to follow the recommendation. We show how simple algebraic manipulations of the usual t-statistic lead to an equivalent test procedure consistent with the recommendation. We provide geometric intuition regarding this equivalence and we consider extensions to testing nested hypotheses in Gaussian linear models. We discuss an application to graphical residual diagnostics where the form of the test statistic makes a practical difference. By examining the formulation of the test statistic from multiple perspectives in this familiar example, we provide simple, concrete illustrations of some important issues that can guide the formulation of effective solutions to more complex statistical problems.Comment: 22 pages, 5 figure

Security oriented e-infrastructures supporting neurological research and clinical trials

The neurological and wider clinical domains stand to gain greatly from the vision of the grid in providing seamless yet secure access to distributed, heterogeneous computational resources and data sets. Whilst a wealth of clinical data exists within local, regional and national healthcare boundaries, access to and usage of these data sets demands that fine grained security is supported and subsequently enforced. This paper explores the security challenges of the e-health domain, focusing in particular on authorization. The context of these explorations is the MRC funded VOTES (Virtual Organisations for Trials and Epidemiological Studies) and the JISC funded GLASS (Glasgow early adoption of Shibboleth project) which are developing Grid infrastructures for clinical trials with case studies in the brain trauma domain

Grid infrastructures for secure access to and use of bioinformatics data: experiences from the BRIDGES project

The BRIDGES project was funded by the UK Department of Trade and Industry (DTI) to address the needs of cardiovascular research scientists investigating the genetic causes of hypertension as part of the Wellcome Trust funded (£4.34M) cardiovascular functional genomics (CFG) project. Security was at the heart of the BRIDGES project and an advanced data and compute grid infrastructure incorporating latest grid authorisation technologies was developed and delivered to the scientists. We outline these grid infrastructures and describe the perceived security requirements at the project start including data classifications and how these evolved throughout the lifetime of the project. The uptake and adoption of the project results are also presented along with the challenges that must be overcome to support the secure exchange of life science data sets. We also present how we will use the BRIDGES experiences in future projects at the National e-Science Centre

Towards a virtual research environment for paediatric endocrinology across Europe

Paediatric endocrinology is a medical specialty dealing with variations of physical growth and sexual development in childhood. Genetic anomalies that can cause disorders of sexual development in children are rare. Given this, sharing and collaboration on the small number of cases that occur is needed by clinical experts in the field. The EU-funded EuroDSD project (www.eurodsd.eu) is one such collaboration involving clinical centres and clinical and genetic experts across Europe. Through the establishment of a virtual research environment (VRE) supporting sharing of data and a variety of clinical and bioinformatics analysis tools, EuroDSD aims to provide a research infrastructure for research into disorders of sex development. Security, ethics and information governance are at the heart of this infrastructure. This paper describes the infrastructure that is being built and the inherent challenges in security, availability and dependability that must be overcome for the enterprise to succeed

Overcoming Barriers to Aquatic Plant Restoration: Addressing Gaps in Species Identification and Planting Techniques in the Intermountain West

Aquatic ecosystems provide many critical and economically valuable benefits, including drinking water, food, recreational opportunities, and water supply for irrigation and agriculture. However, the health of these systems has been severely impacted by human activities such as pollution, land conversion, and introductions of harmful species. Restoring native aquatic plants can help reverse this damage and reestablish benefits, though it is not a common practice. With an objective to increase capacity for aquatic plant restoration in the Intermountain West, I identified and addressed two major barriers: 1) a lack of confidence in aquatic species identification among wetland professionals, and 2) underdeveloped planting techniques that can be used over large scales and result in successful plant establishment. To address the first barrier, I produced the Floating and Submerged Plants of Utah: Pocket Field Guide. The guide contains identification information, images, and interesting facts about 36 aquatic species, as well as a key to the Pondweed family. To address the second barrier, I conducted two field experiments to identify successful and scalable planting techniques in a river delta in the Intermountain West. In these experiments, I examined the performance of different planting methods (how plants are introduced to a site) and planting designs (how plants are arranged within a site; clumped and dispersed designs) for two types of plant materials (stem fragments and plugs—adult plants in soil). I found that planting methods had a significant effect on plant establishment across the plant material types for one of the native species tested, Ruppia cirrhosa, but not the other two species, Potamogeton nodosus and Stuckenia pectinata. I did not find significant effects of planting design. Based on these findings, I suggest that wetland professionals carefully pair different species with planting methods to balance scalability and plant establishment. I also suggest that logistical considerations (such as site accessibility), rather than potential ecological differences (such as species-specific traits that may affect plant establishment), can guide planting design choices. Addressing these barriers will increase the capacity for aquatic plant restoration in the Intermountain West and subsequently support the health of aquatic ecosystems

Grid infrastructures for the electronics domain: requirements and early prototypes from an EPSRC pilot project

The fundamental challenges facing future electronics design is to address the decreasing – atomistic - scale of transistor devices and to understand and predict the impact and statistical variability these have on design of circuits and systems. The EPSRC pilot project “Meeting the Design Challenges of nanoCMOS Electronics” (nanoCMOS) which began in October 2006 has been funded to explore this space. This paper outlines the key requirements that need to be addressed for Grid technology to support the various research strands in this domain, and shows early prototypes demonstrating how these requirements are being addressed

Severe Open Ankle Sprain

[West J Emerg Med. 2011;12(4):581–582.

The pros and cons of using SDL for creation of distributed services

In a competitive market for the creation of complex distributed services, time to market, development cost, maintenance and flexibility are key issues. Optimizing the development process is very much a matter of optimizing the technologies used during service creation. This paper reports on the experience gained in the Service Creation projects SCREEN and TOSCA on use of the language SDL for efficient service creation