Continuous-flow laboratory simulation of stream water quality changes downstream of an untreated wastewater discharge.

In regions of the world with poor provision of wastewater treatment, raw sewage is often discharged directly into surface waters. This paper describes an experimental evaluation of the fate of two organic chemicals under these conditions using an artificial channel cascade fed with a mix of settled sewage and river water at its upstream end and operated under continuous steady-state conditions. The experiments underpin an environmental risk assessment methodology based on the idea of an “impact zone” (IZ) – the zone downstream of wastewater emission in which water quality is severely impaired by high concentrations of unionised ammonia, nitrite and biochemical oxygen demand (BOD). Radiolabelled dodecane-6-benzene sulphonate (DOBS) and aniline hydrochloride were used as the model chemical and reference compound respectively. Rapid changes in 14C counts were observed with flow-time for both these materials. These changes were most likely to be due to complete mineralisation. A dissipation half-life of approximately 7.1 h was observed for the 14C label with DOBS. The end of the IZ was defined as the point at which the concentration of both unionised ammonia and nitrite fell below their respective predicted no-effect concentrations for salmonids. At these points in the cascade, approximately 83 and 90% of the initial concentration of 14C had been removed from the water column, respectively. A simple model of mineral nitrogen transformations based on Michaelis–Menten kinetics was fitted to observed concentrations of NH4, NO2 and NO3. The cascade is intended to provide a confirmatory methodology for assessing the ecological risks of chemicals under direct discharge co

Likelihood-ratio ranking of gravitational-wave candidates in a non-Gaussian background

We describe a general approach to detection of transient gravitational-wave signals in the presence of non-Gaussian background noise. We prove that under quite general conditions, the ratio of the likelihood of observed data to contain a signal to the likelihood of it being a noise fluctuation provides optimal ranking for the candidate events found in an experiment. The likelihood-ratio ranking allows us to combine different kinds of data into a single analysis. We apply the general framework to the problem of unifying the results of independent experiments and the problem of accounting for non-Gaussian artifacts in the searches for gravitational waves from compact binary coalescence in LIGO data. We show analytically and confirm through simulations that in both cases the likelihood ratio statistic results in an improved analysis.Comment: 10 pages, 6 figure

Modelling packed bed structures

Agglomeration is where particles join together during isolation to form clusters, known as agglomerates. These agglomerates then cause issues for further processing, due to varying sizes, strengths and potentially containing impurities, which often results in the material having to be reprocessed or discarded

Progress and promise in understanding the genetic basis of common diseases

Susceptibility to common human diseases is influenced by both genetic and environmental factors. The explosive growth of genetic data, and the knowledge that it is generating, are transforming our biological understanding of these diseases. In this review, we describe the technological and analytical advances that have enabled genome-wide association studies to be successful in identifying a large number of genetic variants robustly associated with common disease. We examine the biological insights that these genetic associations are beginning to produce, from functional mechanisms involving individual genes to biological pathways linking associated genes, and the identification of functional annotations, some of which are cell-type-specific, enriched in disease associations. Although most efforts have focused on identifying and interpreting genetic variants that are irrefutably associated with disease, it is increasingly clear that—even at large sample sizes—these represent only the tip of the iceberg of genetic signal, motivating polygenic analyses that consider the effects of genetic variants throughout the genome, including modest effects that are not individually statistically significant. As data from an increasingly large number of diseases and traits are analysed, pleiotropic effects (defined as genetic loci affecting multiple phenotypes) can help integrate our biological understanding. Looking forward, the next generation of population-scale data resources, linking genomic information with health outcomes, will lead to another step-change in our ability to understand, and treat, common diseases

Is a specialist breathlessness service more effective and cost-effective for patients with advanced cancer and their carers than standard care? Findings of a mixed-method randomised controlled trial.

BACKGROUND: Breathlessness is common in advanced cancer. The Breathlessness Intervention Service (BIS) is a multi-disciplinary complex intervention theoretically underpinned by a palliative care approach, utilising evidence-based non-pharmacological and pharmacological interventions to support patients with advanced disease. We sought to establish whether BIS was more effective, and cost-effective, for patients with advanced cancer and their carers than standard care. METHODS: A single-centre Phase III fast-track single-blind mixed-method randomised controlled trial (RCT) of BIS versus standard care was conducted. Participants were randomised to one of two groups (randomly permuted blocks). A total of 67 patients referred to BIS were randomised (intervention arm n = 35; control arm n = 32 received BIS after a two-week wait); 54 completed to the key outcome measurement. The primary outcome measure was a 0 to 10 numerical rating scale for patient distress due to breathlessness at two-weeks. Secondary outcomes were evaluated using the Chronic Respiratory Questionnaire, Hospital Anxiety and Depression Scale, Client Services Receipt Inventory, EQ-5D and topic-guided interviews. RESULTS: BIS reduced patient distress due to breathlessness (primary outcome: -1.29; 95% CI -2.57 to -0.005; P = 0.049) significantly more than the control group; 94% of respondents reported a positive impact (51/53). BIS reduced fear and worry, and increased confidence in managing breathlessness. Patients and carers consistently identified specific and repeatable aspects of the BIS model and interventions that helped. How interventions were delivered was important. BIS legitimised breathlessness and increased knowledge whilst making patients and carers feel 'not alone'. BIS had a 66% likelihood of better outcomes in terms of reduced distress due to breathlessness at lower health/social care costs than standard care (81% with informal care costs included). CONCLUSIONS: BIS appears to be more effective and cost-effective in advanced cancer than standard care. TRIAL REGISTRATION: RCT registration at ClinicalTrials.gov NCT00678405 (May 2008) and Current Controlled Trials ISRCTN04119516 (December 2008).The study was supported by the following funders: NIHR Research for Patient Benefit (for Phase III RCT funding); Macmillan Cancer Support (MF’s post-doctoral fellowship); The Gatsby Foundation for the initial funding of BIS; and AT Prevost was supported by the National Institute for Health Research (NIHR) Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London. The study sponsor was CUHNFT.This is the final published version. It first appeared at http://www.biomedcentral.com/1741-7015/12/194

Properties of packed bed structures formed during filtration : a two and three-dimensional model

Agglomeration is an issue that causes many problems during secondary processing for pharmaceutical companies, causing material to need further processing, and costing additional time and resources to ensure a satisfactory outcome. A potential source of agglomeration arises from the particle contacts established during filtration that lead to robust agglomerates forming during drying, so that a necessary first step towards understanding agglomeration is to study the packing properties of filtration beds. Here we present two and three-dimensional models simulating the formation of packed bed structures during filtration. The models use circular and spherical particles of different sizes, mimicking the bimodal particle size distributions sometimes encountered in industrial practice. The statistics of packing and void formation, along with the distribution of inter-particle contacts and percolation structures, are presented and discussed in the context of filtration, drying and agglomeration. The model paves the way for predictive capabilities that can lead to the rational design of processes to minimise the impact of agglomeration

A Cosmological No-Hair Theorem

A generalisation of Price's theorem is given for application to Inflationary Cosmologies. Namely, we show that on a Schwarzschild--de Sitter background there are no static solutions to the wave or gravitational perturbation equations for modes with angular momentum greater than their intrinsic spin.Comment: 9 pages, NCL94 -TP4, (Revtex

A systematic review of repetitive task training with modelling of resource use, costs and effectiveness

OBJECTIVES: To determine whether repetitive functional task practice (RFTP) after stroke improves limb-specific or global function or activities of daily living and whether treatment effects are dependent on the amount of practice, or the type or timing of the intervention. Also to provide estimates of the cost-effectiveness of RFTP. DATA SOURCES: The main electronic databases were searched from inception to week 4, September 2006. Searches were also carried out on non-English-language databases and for unpublished trials up to May 2006. REVIEW METHODS: Standard quantitative methods were used to conduct the systematic review. The measures of efficacy of RFTP from the data synthesis were used to inform an economic model. The model used a pre-existing data set and tested the potential impact of RFTP on cost. An incremental cost per quality-adjusted life-year (QALY) gained for RFTP was estimated from the model. Sensitivity analyses around the assumptions made for the model were used to test the robustness of the estimates. RESULTS: Thirty-one trials with 34 intervention-control pairs and 1078 participants were included. Overall, it was found that some forms of RFTP resulted in improvement in global function, and in both arm and lower limb function. Overall standardised mean difference in data suitable for pooling was 0.38 [95% confidence interval (CI) 0.09 to 0.68] for global motor function, 0.24 (95% CI 0.06 to 0.42) for arm function and 0.28 (95% CI 0.05 to 0.51) for functional ambulation. Results suggest that training may be sufficient to have an impact on activities of daily living. Retention effects of training persist for up to 6 months, but whether they persist beyond this is unclear. There was little or no evidence that treatment effects overall were modified by time since stroke or dosage of task practice, but results for upper limb function were modified by type of intervention. The economic modelling suggested that RFTP was cost-effective. Given a threshold for cost-effectiveness of 20,000 pounds per QALY gained, RFTP is cost-effective so long as the net cost per patient is less than 1963 pounds. This result showed some sensitivity to the assumptions made for the model. The cost-effectiveness of RFTP tends to stem from the relatively modest cost associated with this intervention. CONCLUSIONS: The evidence suggests that some form of RFTP can be effective in improving lower limb function at any time after stroke, but that the duration of intervention effect is unclear. There is as yet insufficient good-quality evidence to make any firm recommendations for upper limb interventions. If task-specific training is used, adverse effects should be monitored. While the effectiveness of RFTP is relatively modest, this sort of intervention appears to be cost-effective. Owing to the large number of ongoing trials, this review should be updated within 2 years and any future review should include a comparison against alternative treatments. Further research should evaluate RFTP upper limb interventions and in particular constraint-induced movement therapy, address practical ways of delivering RFTP interventions, be directed towards the evaluation of suitable methods to maintain functional gain, and be powered to detect whether RFTP interventions are cost-effective