Studies on polyunsaturated fatty acid nutrition in the larvae of a marine fish - the herring, Clupea harengus L.

Despite increasing interest in the culture of cold-water marine fish, a satisfactory inert feed for the larvae of these species has not been developed. As a consequence, the majority of information on the nutritional requirements of the larval stages has been inferred from studies on juvenile or adult fish or derived from manipulations of the nutrient contents of live feeds. Although the latter technique has highlighted the importance of long-chain (n-3) polyunsaturated fatty acids (PUFAs), it is insufficiently precise to define the requirements for individual fatty acids. In this study, the (n-3) PUFA nutrition of the larvae of the herring, Clupea harengus L. was studied. Firstly, the ability of the larvae to elongate and desaturate the fatty acids contained in two strains of brine shrimp, Artemia, was considered. Secondly, the feasibility of rearing herring larvae on an inert, microencapsulated diet was considered. Although it was concluded that long-term rearing trials using this method were not viable at the time, larvae weaned onto the inert feed, from live feed, achieved positive growth. Finally, a novel method for incorporating radiolabelled fatty acids, as metabolic tracers, into herring larvae was developed. The viability of using this system for studying the ability of larvae to elongate and desaturate the fatty acids 18:3(n-3) and 20:5(n-3) was demonstrated. The results from all the trials indicated that a high rate of elongation and desaturation of 18:3(n-3) does not occur in herring larvae. Although some ability to elongate 20:5(n-3) to 22:5(n-3) was demonstrated, significant desaturation of this fatty acid to 22:6(n-3) did not occur. It is suggested that the rate of bioconversion of 20:5(n-3) to 22:6(n-3) is too low to be of nutritional significance

Modelling the impacts of climate change on thermal habitat suitability for shallow-water marine fish at a global scale

Funding: EL received no specific funding for this work. C.J.F. received no specific funding for this work. M.T.B was supported by Natural Environment Research Council grant NE/J024082/1 (https://nerc.ukri.org).Understanding and predicting the response of marine communities to climate change at large spatial scales, and distilling this information for policymakers, are prerequisites for ecosystem-based management. Changes in thermal habitat suitability across species’ distributions are especially concerning because of their implications for abundance, affecting species’ conservation, trophic interactions and fisheries. However, most predictive studies of the effects of climate change have tended to be sub-global in scale and focused on shifts in species’ range edges or commercially exploited species. Here, we develop a widely applicable methodology based on climate response curves to predict global-scale changes in thermal habitat suitability. We apply the approach across the distributions of 2,293 shallow-water fish species under Representative Concentration Pathways 4.5 and 8.5 by 2050–2100. We find a clear pattern of predicted declines in thermal habitat suitability in the tropics versus general increases at higher latitudes. The Indo-Pacific, the Caribbean and western Africa emerge as the areas of most concern, where high species richness and the strongest declines in thermal habitat suitability coincide. This reflects a pattern of consistently narrow thermal ranges, with most species in these regions already exposed to temperatures above inferred thermal optima. In contrast, in temperate regions, such as northern Europe, where most species live below thermal optima and thermal ranges are wider, positive changes in thermal habitat suitability suggest that these areas are likely to emerge as the greatest beneficiaries of climate change, despite strong predicted temperature increases.Publisher PDFPeer reviewe

Effects of temperature and salinity on four species of northeastern Atlantic scyphistomae (Cnidaria Scyphozoa)

This work was funded by the MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland), and we gratefully acknowledge that support. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. C.L.W. is also grateful to the US/UK Fulbright Commission and the University of St Andrews for their financial support.Laboratory incubation experiments were conducted to examine the effects of different temperatures (4, 9, 14, 19, 23°C) and salinities (21, 27, 34) on survival and asexual reproduction of scyphistomae of Cyanea capillata, C. lamarckii, Chrysaora hysoscella, and Aurelia aurita in order to better understand how climate variability may affect the timing and magnitude of jellyfish blooms. Significant mortality was observed only for C. capillata and Ch. hysoscella at the highest and lowest temperatures, respectively, but temperature and salinity significantly affected the asexual reproductive output for all species. As temperature increased, production rates of podocysts increased and, if produced, progeny scyphistomae by side budding also increased. However, strobilation rates, and therefore the mean number of ephyrae produced, decreased when scyphistomae were exposed to elevated temperatures. These results provide a mechanistic explanation for why ephyrae of these species tend to be produced during colder periods of the year whilst summer and early autumn are probably important periods for increasing the numbers of scyphistomae in natural populations.PostprintPeer reviewe

Prevalence of HIV in workforces in southern Africa, 2000 - 2001

Objectives. Most data on HIV prevalence in low-risk populations in sub-Saharan Africa are drawn from sentinel surveys of pregnant women attending antenatal clinics and are not representative of formal sector workforces. We surveyed workforces in southern Africa to determine HIV prevalence among formally employed, largely male populations. Methods. Voluntary, anonymous, unlinked seroprevalence surveys of 34 workforces with 44 000 employees were carried out in South Africa, Botswana, and Zambia in 2000 - 2001. Results were stratified to obtain estimates of prevalence by industrial sector, location, age, sex, and job level. Results. Average HIV prevalence for the entire sample was 16.6% (95% CI: 16.3 - 17.0%). Country-wide prevalence was 14.5% (14.1 - 14.9%) in South Africa, 17.9% (17.1 - 18.7%) in Zambia, and 24.6% (23.6 - -25.7%) in Botswana. Among industrial sectors, mining (18.0%, 17.6 - 18.5%) and metal processing (17.3%, 15.9 - 18.7%) had the highest infection rates. Males, who comprised 85% of participants of known sex, were more likely (16.3%, 15.3 - 17.4%) to be infected than were females (10.7%, 8.7 - 12.7%). Contract (23%, 21.9 - 24.1%), unskilled (18.3%, 17.5 - 19.1%), and semi-skilled workers (18.7%, 18.1 - 19.4%) were much more likely to be infected than were skilled workers (10.5%, 9.5 - 11.4%) and managers (4.5%, 3.4 - 5.6%). Participation in the surveys averaged 63% of eligible employees. Conclusions. HIV prevalence among formally employed workers in southern Africa shows different patterns than among antenatal clinic attendees. Anonymous workplace surveys generate prevalence estimates for demographic groups that are not represented in antenatal surveys and can strengthen support for prevention and treatment interventions. S Afr Med J 2004; 94: 125-130

Twittering on about mental health: is it worth the effort?

The medical community disseminates information increasingly using social media. Randomised controlled trials are being conducted in this area to evaluate effectiveness of social media with mixed results so far, but more trials are likely to be published in the coming years. One recent twitter randomised control trial using Cochrane Schizophrenia Group reviews suggests that tweets increase the hits to the target web page by about threefold and time spent on the web page is also increased threefold when referrals come in via twitter. These are early findings and need further replication. Twitter appeals to professionals, entertainers and politicians among others as a means of networking with peers and connecting with the wider public. Twitter, in particular, seems to be well placed for use by the medical community and is effective in promoting messages, updating information, interacting with each other locally and internationally and more so during conferences. Twitter is also increasingly used to disseminate evidence in addition to traditional media such as academic peer-reviewed journals. Caution is required using twitter as inadvertent tweets can lead to censure. Overall, the use of twitter responsibly by the medical community will increase visibility of research findings and ensure up to date evidence is readily accessible. This should open the door for further trials of different social media platforms to evaluate their effectiveness in disseminating accurate high-quality information instantaneously to a global audience

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter

Evidence gathering in support of sustainable Scottish inshore fisheries: work package (4) final report: a pilot study to define the footprint and activities of Scottish inshore fisheries by identifying target fisheries, habitats and associated fish stocks

[Extract from Executive Summary] This work was conducted under Work package 4 of the European Fisheries Funded program “Evidence Gathering in Support of Sustainable Scottish Inshore Fisheries”. The overall aim of the program was to work in partnership with Marine Scotland Fisheries Policy and with the Scottish Inshore Fisheries Groups to help develop inshore fisheries management. Specifically the program aims were to establish the location of fishing activities within inshore areas; to identify catch composition and associated fishery impacts; to define the environmental footprint and availability of stocks; to develop economic value within local fisheries and; to establish an information resource base to assist the development of inshore fisheries management provisions.Publisher PD

Cost-effectiveness analyses for mirtazapine and sertraline in dementia: randomised controlled trial

BACKGROUND Depression is a common and costly comorbidity in dementia. There are very few data on the cost-effectiveness of antidepressants for depression in dementia and their effects on carer outcomes. AIMS To evaluate the cost-effectiveness of sertraline and mirtazapine compared with placebo for depression in dementia. METHOD A pragmatic, multicentre, randomised placebo-controlled trial with a parallel cost-effectiveness analysis (trial registration: ISRCTN88882979 and EudraCT 2006-000105-38). The primary cost-effectiveness analysis compared differences in treatment costs for patients receiving sertraline, mirtazapine or placebo with differences in effectiveness measured by the primary outcome, total Cornell Scale for Depression in Dementia (CSDD) score, over two time periods: 0-13 weeks and 0-39 weeks. The secondary evaluation was a cost-utility analysis using quality-adjusted life years (QALYs) computed from the Euro-Qual (EQ-5D) and societal weights over those same periods. RESULTS There were 339 participants randomised and 326 with costs data (111 placebo, 107 sertraline, 108 mirtazapine). For the primary outcome, decrease in depression, mirtazapine and sertraline were not cost-effective compared with placebo. However, examining secondary outcomes, the time spent by unpaid carers caring for participants in the mirtazapine group was almost half that for patients receiving placebo (6.74 v. 12.27 hours per week) or sertraline (6.74 v. 12.32 hours per week). Informal care costs over 39 weeks were £1510 and £1522 less for the mirtazapine group compared with placebo and sertraline respectively. CONCLUSIONS In terms of reducing depression, mirtazapine and sertraline were not cost-effective for treating depression in dementia. However, mirtazapine does appear likely to have been cost-effective if costing includes the impact on unpaid carers and with quality of life included in the outcome. Unpaid (family) carer costs were lower with mirtazapine than sertraline or placebo. This may have been mediated via the putative ability of mirtazapine to ameliorate sleep disturbances and anxiety. Given the priority and the potential value of supporting family carers of people with dementia, further research is warranted to investigate the potential of mirtazapine to help with behavioural and psychological symptoms in dementia and in supporting carers