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Extensive and dense macroalgal fields can compromise the ecosystem function of habitat mosaics on reefs owing to their limiting effect on patch connectivity. Macroalgae can maintain and increase their dominance with effective self-reinforcing feedback mechanisms. For example, macroalgae can form dense beds, supressing coral settlement and grazing by herbivores. This compromised ecosystem function can lead to major socioeconomic and ecological changes. Dense macroalgal beds were shaded with submerged shade sails of two sizes and changes to the underlying benthos and feeding rates of herbivorous fishes were recorded. The shade sails reduced the algae's ability to photosynthesize by 29%. After 6 weeks, macroalgal cover was reduced by 24% under small sails and by 51% under large sails. Small shade sails reduced turf algal growth by 23%, while large sails reduced growth by 82%. Three months after removal of the shade sails, algal beds had almost completely regrown. During this regrowth period, herbivore bites taken from the experiment's substrates were recorded, with grazing impact reducing significantly with time. This study is the first to achieve macroalgal reduction via the alteration of the light regime. While macroalgae regrew in this relatively short-term experiment, shading may be a viable reef management approach that aims to maximize habitat mosaics on coral reefs, particularly if used in combination with other intervention methods.

SummaryThere is an assumption that tropical sea urchins are macroalgal grazers with the ability to control macroalgal expansion on degraded coral reefs. We surveyed abundances ofEchinothrix calamaris, an urchin species common in the western Indian Ocean on 21 reefs of the inner Seychelles and predicted their density using habitat predictors in a modelling approach. Urchin densities were greatest on patch reef habitat types and declined with increasing macroalgal cover. Next, we experimentally investigated the macroalgae-urchin relationship by penning two sea urchin densities on macroalgal fields. Over six weeks, the highest density treatment (4.44 urchins m−2) cleared 13% of macroalgal cover. This moderate impact leads us to conclude that controlling macroalgal expansion is not likely to be one of the main functions ofE. calamarisin the inner Seychelles given the current densities we found in our surveys (mean: 0.02 urchins m−2, maximum: 0.16 urchins m−2).

This study was conducted to assess the adherence and impact of National institute for Health and Clinical excellence (NICE) guidelines on Computer tomography (CT) imaging of head injuries in the emergency department of Wexham Park Hospital in December 2003 and 2008. A data collection sheet was used to collect information on the CT imaging of head injury patients presenting to Wexham Park Hospital Emergency department in December 2003 and then again in December 2008. 37 patients were included in the audit in 2003 and 47 in 2008. As a consequence of the results in 2003 a change was implemented this consisted of distributing copies of the head injury guidelines and locating them in the areas receiving major trauma in the Emergency department. There was also education given to new doctors starting work in the Emergency department about the head injury guidelines. The data collected in 2008 assessed the impact of this change. In 2003, 30% and in 2008, 17% of head injury patients received the appropriate CT imaging according to criteria 1 of the guidelines. 26% of patients in 2003 with head injuries fulfilled one or more of Criteria 1 of the guideline but did not receive CT imaging. In 2008 this had reduced to only 4% of patients requiring a head CT according to criteria, but not receiving one. This indicates a dramatic improvement following the interventions in the emergency department. This indicates that very simple interventions have increased the adherence to national head injuries imaging guidelines. This intervention is simple, cheap, is time effective to set up, and is easily reproducible in other hospitals and with other sets of guidelines within the emergency department.

Chronic obstructive pulmonary disease (COPD) is the most common chronic respiratory condition in adults and is characterized by progressive airflow limitation that is not fully reversible. The main etiological agents linked with COPD are cigarette smoking and biomass exposure but respiratory infection is believed to play a major role in the pathogenesis of both stable COPD and in acute exacerbations. Acute exacerbations are associated with more rapid decline in lung function and impaired quality of life and are the major causes of morbidity and mortality in COPD. Preventing exacerbations is a major therapeutic goal but currently available treatments for exacerbations are not very effective. Historically, bacteria were considered the main infective cause of exacerbations but with the development of new diagnostic techniques, respiratory viruses are also frequently detected in COPD exacerbations. This article aims to provide a state-of-the art review of current knowledge regarding the role of infection in COPD, highlight the areas of ongoing debate and controversy, and outline emerging technologies and therapies that will influence future diagnostic and therapeutic pathways in COPD.