The influence of signal crayfish on fine sediment dynamics and macroinvertebrate communities in lowland rivers

The spread of non-native species is a global threat and the rate at which biological invasions occur is likely to increase in the future. This thesis examines the implications of the invasive signal crayfish, Pacifastacus leniusculus (Dana), for instream communities and abiotic processes within lowland rivers in England. The potential effects on lotic macroinvertebrate communities and fine sediment dynamics are investigated at a range of spatial and temporal scales, from the examination of national long-term datasets through to short-term detailed mesocosm experiments. Interrogation of macroinvertebrate community data from three English regions was undertaken to understand the temporal and spatial extent of signal crayfish effects. Invasive crayfish had significant long-term and persistent effects on resident macroinvertebrate communities regardless of the lithology or other environmental characteristics of the region. The resultant modifications to community composition had repercussions for several widely employed freshwater biomonitoring tools which employ faunal abundance in their derivation. A reach-scale field study was undertaken at two sites, one invaded by crayfish and one which did not support populations of crayfish (control), to assess the potential contribution of signal crayfish for fine sediment dynamics (ingress, fluxes and ultimately the overall implications for sediment budgets). Reach-scale field experiments examining the effect of crayfish invasion on resident macroinvertebrate communities over a 126-day period indicated that once crayfish populations are well-established their effects are persistent. However, separating the effects of crayfish from wider macroinvertebrate community dynamics and life-history characteristics of the invader and resident taxa means that attributing the effects is far from clear. The thesis presents the results of a series of novel mesocosm experiments which examined the dynamic and two-way interactions of predator-prey relationships and potential zoogeomorphological effects of signal crayfish and the freshwater shrimp, Gammarus pulex. Signal crayfish had a significant effect on the mass of fine sediment infiltrating into the gravel matrix associated with foraging and predatory activity; however this was strongly controlled by prey availability. Finally, through the development of conceptual models, the thesis illustrates the need for greater integration of ecological and geomorphological theories, at relevant environmental scales (temporal and spatial) to achieve truly interdisciplinary research

Respiratory Therapy Modalities in the Treatment of Acute Respiratory Failure

Rapid advances have been made in the field of respiratory therapy in the past several years, resulting in an increasing sophistication and range of application. Properly applied, these modalities have led to significantly increased survival in patients with acute respiratory failure and a decreased morbidity among individuals with chronic pulmonary insufficiency. It is the purpose of this article to put into perspective respiratory therapy techniques and their application in the treatment of acute respiratory failure. To this end, we may divide respiratory therapy into five categories: 1) oxygen delivery, 2) airway hygiene, 3) expansion therapy (lung inflation), 4) artificial airways, and 5) mechanical ventilation

Recent Advances in the Management of Chronic Airway Obstruction

Recent advances in our understanding of the natural history of chronic airway obstruction have identified aspects of this process that may enhance the morbidity and mortality of patients with a progressive increase in airway resistance. These advances have helped us to be more specific in the investigation and quantitation of the disease in the pulmonary function laboratory and to be more precise in our therapeutic management. Experience has taught us that the most useful measurement with which to characterize the degree of disease and its rate of progression is the forced expired volume in one second (FEV1). The comprehensive studies of Dr. Charles Fletcher in London have demonstrated that the single most important therapeutic factor is avoidance of all airway irritants. The application of aggressive bronchial hygiene in patients with obstructive airways disease may produce an initial improvement in the FEV1 but will not in itself alter the rate of decline in pulmonary function. As the degree of airway obstruction increases, a number of interrelated physiologic abnormalities develop including hypoxemia, hypercarbia, polycythemia, cor pulmonale, and eventually, acute or chronic respiratory failure. These abnormalities account for most of the morbidity in this condition and the majority of patients who develop them have a high degree of airway obstruction. It is not unusual, however, to see patients with a moderate degree of airway obstruction who also manifest these problems. The purpose of this paper is: (1) to review the relationship between a progressive increase in airway obstruction and the associated physiologic abnormalities, and (2) to discuss the therapeutic interventions that show promise of reducing the morbidity from these accelerated physiologic abnormalities

Improvements in prevalence trend fitting and incidence estimation in EPP 2013

OBJECTIVE: Describe modifications to the latest version of the Joint United Nations Programme on AIDS (UNAIDS) Estimation and Projection Package component of Spectrum (EPP 2013) to improve prevalence fitting and incidence trend estimation in national epidemics and global estimates of HIV burden. METHODS: Key changes made under the guidance of the UNAIDS Reference Group on Estimates, Modelling and Projections include: availability of a range of incidence calculation models and guidance for selecting a model; a shift to reporting the Bayesian median instead of the maximum likelihood estimate; procedures for comparison and validation against reported HIV and AIDS data; incorporation of national surveys as an integral part of the fitting and calibration procedure, allowing survey trends to inform the fit; improved antenatal clinic calibration procedures in countries without surveys; adjustment of national antiretroviral therapy reports used in the fitting to include only those aged 15–49 years; better estimates of mortality among people who inject drugs; and enhancements to speed fitting. RESULTS: The revised models in EPP 2013 allow closer fits to observed prevalence trend data and reflect improving understanding of HIV epidemics and associated data. CONCLUSION: Spectrum and EPP continue to adapt to make better use of the existing data sources, incorporate new sources of information in their fitting and validation procedures, and correct for quantifiable biases in inputs as they are identified and understood. These adaptations provide countries with better calibrated estimates of incidence and prevalence, which increase epidemic understanding and provide a solid base for program and policy planning

National evaluation of the neighbourhood nurseries: integrated report

Report description: The NNI was launched in 2001 to provide high quality childcare in the most disadvantaged neighbourhoods of England, to help parents into employment, reduce child poverty and boost children’s development. By 2005 45,000 new childcare places had been created in approximately 1,400 neighbourhood nurseries. This report brings together the findings of the four individual strands of the National Evaluation of Neighbourhood Nurseries Initiative as shown above and makes a number of recommendations. The report shows the rationale for the government’s strategy in targeting disadvantaged neighbourhoods and in focusing on high quality childcare to provide the link between raising parental employment and income and improving children’s life chances

Widening access to medical education for under-represented socioeconomic groups: population based cross sectional analysis of UK data, 2002-6

Objective To determine whether new programmes developed to widen access to medicine in the United Kingdom have produced more diverse student populations

A Systematic Review of Dental Disease in Patients Undergoing Cancer Therapy

Introduction: The purpose of this systematic review was to evaluate the literature and update our current understanding of the impact of present cancer therapies on the dental apparatus (teeth and periodontium) since the 1989 NIH Development Consensus Conference on the Oral Compli­cations of Cancer Therapies. Review Method: A systematic literature search was con­ducted with assistance from a research librarian in the databases MEDLINE/PubMed and EMBASE for articles published between 1 January 1990 and 31 December 2008. Each study was independently assessed by two reviewers. Taking into account predetermined quality measures, a weighted prevalence was calculated for the prevalence of dental caries, severe gingival disease, and dental infection. Data on DMFT/dmft, DMFS/dmfs, plaque, and gingival indexes were also gathered. The level of evidence, recommendation, and guideline (if possible) were given for published preventive and management strategies. Results: Sixty-four published papers between 1990 and 2008 were reviewed. The weighted overall prevalence of dental caries was 28.1%. The overall DMFT for patients who were post-antineoplastic therapy was 9.19 (SD, 7.98; n=457). The overall plaque index for patients who were post­antineoplastic therapy was 1.38 (SD, 0.25; n=189). The GI for patients who were post-chemotherapy was 1.02 (SD, 0.15; n=162). The weighted prevalence of dental infections/ abscess during chemotherapy was reported in three studies and was 5.8%. Conclusions: Patients who were post-radiotherapy had the highest DMFT. The use of fluoride products and chlorhex­idine rinses are beneficial in patients who are post-radiotherapy. There continues to be lack of clinical studies on the extent and severity of dental disease that are associated with infectious complications during cancer therapy

Discharge and suspended sediment time series as controls on fine sediment ingress into gravel river beds

Fine sediment availability and channel hydraulics are two of the primary controls on the ingress of fine sediment into gravel river beds. A novel dataset consisting of fine sediment ingress measurements coupled with high-resolution turbidity and discharge time series, was analysed to investigate relations between ingress, discharge and turbidity. Discharge and turbidity demonstrated a weak association with each other, and their relations with fine sediment ingress were relatively weak. An alternative, but widely applied ‘redundancy’ approach was investigated that focused on key metrics, or facets, of the discharge and turbidity time series and their association with fine sediment ingress. Principal component analysis was used to distil the most important facets driving variation in the discharge and turbidity datasets and these were then used as independent variables in regression models with sediment ingress as the dependent variable. These models accounted for a larger amount of the statistical variation in sediment ingress over time than discharge and turbidity time series. Facets of the turbidity time series were found to be the most effective explanatory variables. The results suggest that this approach could be valuable and justify its application and testing across a range of river types in different hydrological and sedimentary settings. Application of this method could improve our generic understanding of what controls ingress at larger spatial and temporal scales and therefore complements process-based approaches, which is vital for the development of fine sediment management strategies