1,274 research outputs found
Impacts of a South African coastal golf estate on shrubland bird communities
Golf courses and estates are one form of development threatening coastal vegetation in South Africa's Cape Floristic Region. They occupy substantial tracts of land, fragmenting indigenous vegetation. This study investigates the effects on bird community structure and function of replacing natural Strandveld vegetation with a 170-ha golf estate in which 46 ha of Strandveld vegetation was retained in conditions ranging from pristine to moderately degraded. Bird assemblages of the remaining Strandveld patches in the golf estate were compared with those of an adjacent Strandveld conservation area. Field work was conducted during the birds' breeding season, in October and November 2005. The golf estate was more species rich overall, but many species were uncommon, several were present only as a consequence of the creation of new habitats, and species were not evenly distributed across the remaining Strandveld fragments. Bird diversity and abundance were significantly higher in the adjacent conservation area. It is estimated that more than 8500 individual birds were displaced by construction of the golf estate and four Strandveld species were not represented at all within the estate. Within the estate, species richness rose with increasing Strandveld patch size and the minimum area of continuous pristine vegetation required to maintain the natural species assemblage was estimated at 51 ha. The golf estate was characterized by a high proportion of generalist and granivorous species, but at the cost of reduced numbers of frugivores and nectarivores. Energy flow through the bird communities in the two areas was thus markedly different, and pollination and fruit dispersal potential within the golf estate were reduced substantially. Golf courses and golf estates inevitably will not substitute for the natural habitats they have replaced, but careful design with input from ecological theory can reduce the adverse effects of fragmentation
Pulmonary artery pressure and activities in chronic heart failure
AbstractLong-term continuous pulmonary artery pressure monitoring was used to investigate pressure changes during different types of exercise and normal daily activities in patients with chronic heart failure. Nine men (mean age 55 years) with treated chronic heart failure underwent continuous pulmonary artery pressure measurement with use of a micromanometer-tipped catheter with in vivo calibration and frequency-modulated recording.The mean (± SD) maximal systolic pulmonary artery pressure (in mm Hg) was 59.4 ± 26.1 on treadmill exercise, 54.9 ± 30.6 on bicycle exercise, 52.5 ± 26.1 walking up and down state and 43.5 ± 23.9 walking on a flat surface. The mean maximal diastolic pressure (in mm Hg) was 27.8 ± 14.6 on treadmill exercise, 25.5 ± 14.9 on bicycle exercise, 24.9 ± 14.8 walking up and down stairs and 20.4 ± 12.5 walking on a flat surface. The increase in pulmonary artery pressure did not correlate with the severity of the limiting symptoms except during walking on a flat surface.All patients had marked postural changes in pressure, with the systolic pressure difference from lying to standing ranging from 8 to 25 mm Hg and the diastolic pressure difference ranging from 3 to 13 mm Hg. Eating meals caused an increase in pressure in three patients, but less than that when lying flat. There was an increase in pressure during urination in four patients equal to that when walking on a flat surface. None of these activities was associated with symptoms.Neither symptoms nor pulmonary artery pressure during maximal exercise is the same as during daily activities. This may restrict the value of maximal exercise tests in assessing patients with chronic heart failure
Effect of a triplex-binding ligand on triple helix formation at a site within a natural DNA fragment
ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats
Cardiomyopathies are a heterogeneous group of myocardial disorders of mostly unknown etiology, and they occur commonly in cats. In some cats, they are well-tolerated and are associated with normal life expectancy, but in other cats they can result in congestive heart failure, arterial thromboembolism or sudden death. Cardiomyopathy classification in cats can be challenging, and in this consensus statement we outline a classification system based on cardiac structure and function (phenotype). We also introduce a staging system for cardiomyopathy that includes subdivision of cats with subclinical cardiomyopathy into those at low risk of life-threatening complications and those at higher risk. Based on the available literature, we offer recommendations for the approach to diagnosis and staging of cardiomyopathies, as well as for management at each stage
An introduction to data reduction: space-group determination, scaling and intensity statistics
A summary of how to run the data-reduction programs in the CCP4 suite
Climate change, climatic variation and extreme biological responses
Extreme climatic events could be major drivers of biodiversity change, but it is unclear whether extreme biological changes are (i) individualistic (species- or group-specific), (ii) commonly associated with unusual climatic events and/or (iii) important determinants of long-term population trends. Using population time series for 238 widespread species (207 Lepidoptera and 31 birds) in England since 1968, we found that population 'crashes' (outliers in terms of species' year-to-year population changes) were 46% more frequent than population 'explosions'. (i) Every year, at least three species experienced extreme changes in population size, and in 41 of the 44 years considered, some species experienced population crashes while others simultaneously experienced population explosions. This suggests that, even within the same broad taxonomic groups, species are exhibiting individualistic dynamics, most probably driven by their responses to different, short-term events associated with climatic variability. (ii) Six out of 44 years showed a significant excess of species experiencing extreme population changes (5 years for Lepidoptera, 1 for birds). These 'consensus years' were associated with climatically extreme years, consistent with a link between extreme population responses and climatic variability, although not all climatically extreme years generated excess numbers of extreme population responses. (iii) Links between extreme population changes and long-term population trends were absent in Lepidoptera and modest (but significant) in birds. We conclude that extreme biological responses are individualistic, in the sense that the extreme population changes of most species are taking place in different years, and that long-term trends of widespread species have not, to date, been dominated by these extreme changes.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'
A comparison of hirudin with heparin in the prevention of restenosis after coronary angioplasty
__Background:__ The likelihood of restenosis is a major limitation of coronary angioplasty. We studied whether hirudin, a highly selective inhibitor of thrombin with irreversible effects, would prevent restenosis after angioplasty. We compared two regimens of recombinant hirudin with heparin.
__Methods:__ We randomly assigned 1141 patients with unstable angina who were scheduled for angioplasty to receive one of three treatments: (1) a bolus dose of 10,000 IU of heparin followed by an intravenous infusion of heparin for 24 hours and subcutaneous placebo twice daily for three days (382 patients), (2) a bolus dose of 40 mg of hirudin followed by an intravenous infusion of hirudin for 24 hours and subcutaneous placebo twice daily for three days (381 patients), or (3) the same hirudin regimen except that 40 mg of hirudin was given subcutaneously instead of placebo twice daily for three days (378 patients). The primary end point was event-free survival at seven months. Other end points were early cardiac events (within 96 hours), bleeding and other complications of the study treatment, and angiographic measurements of coronary diameter at six months of follow-up.
__Results:__ At seven months, event-free survival was 67.3 percent in the group receiving heparin, 63.5 percent in the group receiving intravenous hirudin, and 68.0 percent in the group receiving both intravenous and subcutaneous hirudin (P=0.61). However, the administration of hirudin was associated with a significant reduction in early cardiac events, which occurred in 11.0, 7.9, and 5.6 percent of patients in the respective groups (combined relative risk with hirudin, 0.61; 95 percent confidence interval, 0.41 to 0.90; P=0.023). The mean minimal luminal diameters in the respective groups on follow-up angiography at six months were 1.54, 1.47, and 1.56 mm.
__Conclusions:__ Although significantly fewer early cardiac events occurred with hirudin than with heparin, hirudin had no apparent benefit with longer-term follow-up
Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter
Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the “Intersexual Competition Hypothesis” for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in that they have a wider habitat and trophic niche during the Antarctic Winter (in comparison to Summer). We also detected individual specialization in feeding/trophic levels for each gender, with certain males feeding mainly on fish and certain females mainly on crustaceans, which may be driven the prevailing environmental conditions that lead individuals to search for alternative prey, and cause sexual diet segregation. Our results provide further information to help improve understanding about sexual segregation and individual specialization of marine organisms, while contributing valuable information on the winter diet for Antarctic monitoring programs and for modelling Antarctic marine food webs
Differential disgust responding in people with cancer and implications for psychological wellbeing
Objectives: Evidence suggests that disgust responses, known to negatively affect psychological wellbeing, may differ in people with cancer. We performed the first quantitative investigation of three discrete types of disgust trait - disgust propensity, sensitivity, and self-directed disgust - in people diagnosed with a broad range of cancers (versus cancer-free controls), and explored their associations with psychological wellbeing. Design: In a cross-sectional survey design, 107 participants with heterogeneous cancer diagnoses, recruited from cancer charities and support groups, were matched with cancer-free controls by age and gender. Outcome measures: Measures of the three disgust traits were taken alongside measures of anxiety and depression. Results: Disgust sensitivity and physical self-disgust were significantly higher in the cancer than control sample, while disgust propensity and behavioural self-disgust were lower. The disgust traits had a different pattern of associations to psychological wellbeing across the two groups, with disgust sensitivity predicting depressive symptoms to a significantly greater extent in the cancer than control group. Conclusions: People with cancer differ from matched controls in their disgust responses and these responses have significant predictive relationships with aspects of their psychological wellbeing. The results suggest that emotion-based interventions may be useful for improving psychological wellbeing in people with cancer
- …