1,327 research outputs found
The potential for using acoustic tracking to monitor the movement of the West Coast rock lobster Jasus lalandii
Although acoustic tracking has been used to study the movement of several species of clawed and spiny lobsters, only recent technological advances have provided sufficiently small transmitters to examine the utility of using acoustic tracking as a means to analyse the movement of relatively small spiny lobsters, such as Jasus lalandii. The effect of the transmitter on the mobility of J. lalandii was tested in aquarium experiments and was shown to have no influence on movement in three separate experiments. Thereafter, adult male rock lobsters (86–98mm carapace length) were tracked in field trials for up to 32 days at Betty's Bay (n = 4) and Hermanus (n = 5) off the Western Cape, South Africa. Tracking J. lalandii in the field using acoustic tags was successful, even in areas with dense kelp beds and rocky outcrops. The signal from the transmitters was readily detectable from the surface and subsequent use of underwater tracking equipment enabled visual confirmation of the position of the rock lobsters. Lobsters moved significantly longer distances (>45m day−1) in the first two days following tagging than during any subsequent time period (<10m day−1). This suggests that transmitter attachment and/or handling altered the movement pattern for the first 72 hours after tagging. During the period of observation, J. lalandii displayed classical nomadic behaviour
Recommended from our members
Vitamin D intake and risk of CVD and all-cause mortality: evidence from the Caerphilly Prospective Cohort Study
OBJECTIVE:
Prospective data on the associations between vitamin D intake and risk of CVD and all-cause mortality are limited and inconclusive. The aim of the present study was to investigate the associations between vitamin D intake and CVD risk and all-cause mortality in the Caerphilly Prospective Cohort Study.
DESIGN:
The associations of vitamin D intake with CVD risk markers were examined cross-sectionally at baseline and longitudinally at 5-year, 10-year and >20-year follow-ups. In addition, the predictive value of vitamin D intake for CVD events and all-cause mortality after >20 years of follow-up was examined. Logistic regression and general linear regression were used for data analysis.
SETTING:
Participants in the UK.
SUBJECTS:
Men (n 452) who were free from CVD and type 2 diabetes at recruitment.
RESULTS:
Higher vitamin D intake was associated with increased HDL cholesterol (P=0·003) and pulse pressure (P=0·04) and decreased total cholesterol:HDL cholesterol (P=0·008) cross-sectionally at baseline, but the associations were lost during follow-up. Furthermore, higher vitamin D intake was associated with decreased concentration of plasma TAG at baseline (P=0·01) and at the 5-year (P=0·01), but not the 10-year examination. After >20 years of follow-up, vitamin D was not associated with stroke (n 72), myocardial infarctions (n 142), heart failure (n 43) or all-cause mortality (n 281), but was positively associated with increased diastolic blood pressure (P=0·03).
CONCLUSIONS:
The study supports associations of higher vitamin D intake with lower fasting plasma TAG and higher diastolic blood pressure
Performance characteristics of ELISA to detect bovine viral diarrhea virus (BVDV) antibodies using colostrum
Colostrum contains substantially higher concentrations of immunoglobulins (Igs) when compared with serum or milk, which may improve the diagnostic sensitivity of an antibody ELISA when using colostrum. In this study, BVD was used as a model to identify the performance characteristics of colostrum and to assess the potential for increased ELISA sensitivity when compared with serum. Blood and colostrum samples were collected from cows within two dairy cattle herds: a previously infected and BVD-vaccinated Holstein-Friesian (positive herd) herd, and a bulk-tank milk antibody negative (negative herd) Jersey herd. All samples were tested using a commercial BVDV antibody ELISA. Median sample-to-positive (S/P) colostrum ratios were significantly higher than their respective serum counterparts, and positive herd S/P ratios were significantly higher than the respective negative herd values (P < 0.001). Using the manufacturer’s recommended serum dilution (1:5) and colostrum dilution (undiluted), and a cut-off threshold S/P ratio of 0.2, diagnostic sensitivity (DSe) and diagnostic specificity (DSp) for colostrum were 100% and 70%, respectively. These values increased to 100% DSe and 100% DSp with an increase in cut-off threshold S/P to 0.5. At a sample dilution of 1:100, the DSe of colostrum was 90% and significantly higher compared with serum (DSe 17%). Colostrum has the potential to improve identification of previously infected animals, either individually, or when using pooled samples.Caitlin J. Jenvey, Andrew M. Weir, Michael P. Reichel, Peter D. Cockcrof
Population weighted raster maps can communicate findings of social audits: examples from three continents
<p>Abstract</p> <p>Background</p> <p>Maps can portray trends, patterns, and spatial differences that might be overlooked in tabular data and are now widely used in health research. Little has been reported about the process of using maps to communicate epidemiological findings.</p> <p>Method</p> <p>Population weighted raster maps show colour changes over the study area. Similar to the rasters of barometric pressure in a weather map, data are the health occurrence – a peak on the map represents a higher value of the indicator in question. The population relevance of each sentinel site, as determined in the stratified last stage random sample, combines with geography (inverse-distance weighting) to provide a population-weighted extension of each colour. This transforms the map to show population space rather than simply geographic space.</p> <p>Results</p> <p>Maps allowed discussion of strategies to reduce violence against women in a context of political <it>sensitivity</it> about quoting summary indicator figures. <it>Time-series maps</it> showed planners how experiences of health services had deteriorated despite a reform programme; where in a country HIV risk behaviours were improving; and how knowledge of an economic development programme quickly fell off across a region. <it>Change maps</it> highlighted where indicators were improving and where they were deteriorating. Maps of <it>potential impact of interventions</it>, based on multivariate modelling, displayed how partial and full implementation of programmes could improve outcomes across a country. <it>Scale</it> depends on context. To support local planning, district maps or local government authority maps of health indicators were more useful than national maps; but multinational maps of outcomes were more useful for regional institutions. Mapping was useful to illustrate in which districts enrolment in religious schools – a <it>rare occurrence</it> - was more prevalent.</p> <p>Conclusions</p> <p>Population weighted raster maps can present social audit findings in an accessible and compelling way, increasing the use of evidence by planners with limited numeracy skills or little time to look at evidence. Maps complement epidemiological analysis, but they are not a substitute. Much less do they substitute for rigorous epidemiological designs, like randomised controlled trials.</p
Covalent grafting of molecular catalysts on C₄NₓH_{y} as robust, efficient and well-defined photocatalysts for solar fuel synthesis
The covalent attachment of molecules to 2D materials is an emerging area as strong covalent chemistry offers new hybrid properties and greater mechanical stability compared with nanoparticles. A nickel bis-aminothiophenol catalyst was grafted onto a range of 2D carbon nitrides C₄NₓH_{y} to form noble metal-free photocatalysts for H2 production. The hybrids produce H_{2} beyond 8 days with turnover numbers reaching 1360 based on nickel, a more than 3 fold higher durability than reported molecular catalyst-carbon nitride mixtures, and under longer wavelengths (>475 nm). Time-resolved spectroscopy reveals sub-microsecond electron transfer to the grafted catalyst, six orders of magnitude faster compared with similar reports of non-grafted catalysts. The photoelectrons on the catalyst have a ca. 1000 times longer half-time (7 ms) compared with bare carbon nitride (10 μs). The grafting strategy operates across a range of molecular catalyst-carbon nitride combinations, thus paving the way for robust efficient photocatalysts based on low-cost tunable components
Use of social audits to examine unofficial payments in government health services: experience in South Asia, Africa, and Europe
<p>Abstract</p> <p>Background</p> <p>Unofficial payments in health services around the world are widespread and as varied as the health systems in which they occur. We reviewed the main lessons from social audits of petty corruption in health services in South Asia (Bangladesh, Pakistan), Africa (Uganda and South Africa) and Europe (Baltic States).</p> <p>Methods</p> <p>The social audits varied in purpose and scope. All covered representative sample communities and involved household interviews, focus group discussions, institutional reviews of health facilities, interviews with service providers and discussions with health authorities. Most audits questioned households about views on health services, perceived corruption in the services, and use of government and other health services. Questions to service users asked about making official and unofficial payments, amounts paid, service delivery indicators, and satisfaction with the service.</p> <p>Results</p> <p>Contextual differences between the countries affected the forms of petty corruption and factors related to it. Most households in all countries held negative views about government health services and many perceived these services as corrupt. There was little evidence that better off service users were more likely to make an unofficial payment, or that making such a payment was associated with better or quicker service; those who paid unofficially to health care workers were not more satisfied with the service. In South Asia, where we conducted repeated social audits, only a minority of households chose to use government health services and their use declined over time in favour of other providers. Focus groups indicated that reasons for avoiding government health services included the need to pay for supposedly free services and the non-availability of medicines in facilities, often perceived as due to diversion of the supplied medicines.</p> <p>Conclusions</p> <p>Unofficial expenses for medical care represent a disproportionate cost for vulnerable families; the very people who need to make use of supposedly free government services, and are a barrier to the use of these services. Patient dissatisfaction due to petty corruption may contribute to abandonment of government health services. The social audits informed plans for tackling corruption in health services.</p
Impact of a hospital improvement initiative in Bangladesh on patient experiences and satisfaction with services: two cross-sectional studies
<p>Abstract</p> <p>Background</p> <p>The Bangladesh government implemented a pilot Hospital Improvement Initiative (HII) in five hospitals in Sylhet division between 1998 and 2003. This included management and behaviour change training for staff, waste disposal and procurement, and referral arrangements. Two linked cross-sectional surveys in 2000 and 2003 assessed the impact of the HII, assessing both patients' experience and satisfaction and public views and use of the hospitals.</p> <p>Methods</p> <p>In each survey we asked 300 consecutive outpatients and a stratified random sample of 300 inpatients in the five hospitals about waiting and consultation time, use of an agent for admission, and satisfaction with privacy, cleanliness, and staff behaviour. The field teams observed cleanliness and privacy arrangements, and visited a sample of households in communities near the hospitals to ask about their opinions and use of the hospital services. Analysis examined changes over time in patients' experience and views. Multivariate analysis took account of other variables potentially associated with the outcomes. Survey managers discussed the survey findings with gender stratified focus groups in each sample community.</p> <p>Results</p> <p>Compared with 2000, an outpatient in three of the hospitals in 2003 was more likely to be seen within 10 minutes and for at least five minutes by the doctor, but outpatients were less likely to report receiving all the prescribed medicines from the hospital. In 2003, inpatients were more likely to have secured admission without using an agent. Although patients’ satisfaction with several aspects of care improved, most changes were not statistically significant. Households in 2003 were significantly more likely to rate the hospitals as good than in 2000. Use of the hospitals did not change, except that more households used the medical college hospital for inpatient care in 2003. Focus groups confirmed criticisms of services and suggested improvements.</p> <p>Conclusion</p> <p>Improvements in some aspects of patients' experience may have been due to the programme, but the decreased availability of medicines in government facilities across the country over the period also occurred in these hospitals. Monitoring patients’ experience and satisfaction as well as public views and use of hospital services is feasible and useful for assessing service interventions.</p
Bis(μ-2-tert-butylphenylimido-1:2κ2 N:N)chlorido-2κCl-(diethyl ether-1κO)(2η5-pentamethylcyclopentadienyl)lithiumtantalum(V)
In the title compound, [LiTa(C10H15)(C10H13N)2Cl(C4H10O)], the TaV atom is coordinated by a η5-pentamethylcyclopentadienyl (Cp*) ligand, a chloride ion and two N-bonded 2-tert-butylphenylimide dianions. With respect to the two N atoms, the chloride ion and the centroid of the Cp* ring, the tantalum coordination geometry is approximately tetrahedral. The lithium cation is bonded to both the 2-tert-butylphenylimide dianions and also a diethyl ether molecule, in an approximate trigonal planar arrangement. The Ta⋯Li separation is 2.681 (15) Å. In the crystal, a weak C—H⋯Cl interaction links the molecules. When compared to the 2,6-diisopropylphenylimide analogue (‘the Wigley derivative’) of the title compound, the two structures are conformationally matched with an overall r.m.s. difference of 0.461Å
- …