1,446 research outputs found

    Planning for Persistence in Marine Reserves: A Question of Catastrophic importance

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    Large-scale catastrophic events, although rare, lie generally beyond the control of local management and can prevent marine reserves from achieving biodiversity outcomes. We formulate a new conservation planning problem that aims to minimize the probability of missing conservation targets as a result of catastrophic events. To illustrate this approach we formulate and solve the problem of minimizing the impact of large-scale coral bleaching events on a reserve system for the Great Barrier Reef, Australia. We show that by considering the threat of catastrophic events as part of the reserve design problem it is possible to substantially improve the likely persistence of conservation features within reserve networks for a negligible increase in cost. In the case of the Great Barrier Reef, a 2% increase in overall reserve cost was enough to improve the long-run performance of our reserve network by >60%. Our results also demonstrate that simply aiming to protect the reefs at lowest risk of catastrophic bleaching does not necessarily lead to the best conservation outcomes, and enormous gains in overall persistence can be made by removing the requirement to represent all bioregions in the reserve network. We provide an explicit and well-defined method that allows the probability of catastrophic disturbances to be included in the site selection problem without creating additional conservation targets or imposing arbitrary presence/absence thresholds on existing data. This research has implications for reserve design in a changing climate

    Challenges in collecting clinical samples for research from pregnant women of South Asian origin: evidence from a UK study.

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    Objective: To recruit South Asian pregnant women, living in the UK, into a clinicoepidemiological study for the collection of lifestyle survey data and antenatal blood and to retain the women for the later collection of cord blood and meconium samples from their babies for biochemical analysis. Design: A longitudinal study recruiting pregnant women of South Asian and Caucasian origin living in the UK. Setting: Recruitment of the participants, collection of clinical samples and survey data took place at the 2 sites within a single UK Northern Hospital Trust. Participants: Pregnant women of South Asian origin (study group, n=98) and of Caucasian origin (comparison group, n=38) living in Leeds, UK. Results: Among the participants approached, 81% agreed to take part in the study while a ‘direct approach’ method was followed. The retention rate of the participants was a remarkable 93.4%. The main challenges in recruiting the ethnic minority participants were their cultural and religious conservativeness, language barrier, lack of interest and feeling of extra ‘stress’ in taking part in research. The chief investigator developed an innovative participant retention method, associated with the women’s cultural and religious practices. The method proved useful in retaining the participants for about 5 months and in enabling successful collection of clinical samples from the same mother–baby pairs. The collection of clinical samples and lifestyle data exceeded the calculated sample size required to give the study sufficient power. The numbers of samples obtained were: maternal blood (n=171), cord blood (n=38), meconium (n=176), lifestyle questionnaire data (n=136) and postnatal records (n=136). Conclusions: Recruitment and retention of participants, according to the calculated sample size, ensured sufficient power and success for a clinicoepidemiological study. Results suggest that development of trust and confidence between the participant and the researcher is the key to the success of a clinical and epidemiological study involving ethnic minorities

    Predicting breastfeeding in women living in areas of economic hardship : explanatory role of the theory of planned behaviour

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    This study employed the theory of planned behaviour (TPB) and additional variables (descriptive norm, moral norm, self-identity) to investigate the factors underlying breastfeeding intention and subsequent breastfeeding at four time points (during hospital stay, at hospital discharge, 10 days postpartum and 6 weeks postpartum) in a sample of women selected from defined areas of economic hardship (N = 248). A model containing the TPB, additional variables and demographic factors provided a good prediction of both intention (R-2 = 0.72; attitude, perceived behavioural control, moral norm and self-identity significant predictors) and behaviour - breastfeeding at birth (88.6% correctly classified; household deprivation, intention, attitude significant), at discharge from hospital (87.3% correctly classified; intention, attitude significant), 10 days after discharge (83.1% correctly classified; education, intention, attitude, descriptive norm significant) and 6 weeks after discharge (78.0% correctly classified; age, household deprivation, ethnicity, moral norm significant). Implications for interventions are discussed, such as the potential usefulness of targeting descriptive norms, moral norms and perceived behavioural control (PBC) when attempting to increase breastfeeding uptake

    Occurrence and Reproduction of the Alabama Shad, Alosa alabamae Jordan and Evermann, in the Ouachita River System of Arkansas

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    The anadromous Alabama shad, Alosa alabamae, has drastically declined in abundance in recent decades throughout its historic range and has previously been reported in Arkansas from only five localities. Three of those locality records are pre- 1900. Sampling by seine in the Ouachita River drainage system of southern Arkansas in July and August of 1997 and 1998 produced more than 300 juvenile A. alabamae from two localities on the Little Missouri River and four localities on the Ouachita River. One record of an adult Alabama shad, taken on 4 April1997 by an angler below Remmel Dam on the Ouachita River, was also documented. Adults apparently ascended the Ouachita River and spawned successfully in 1997 and 1998 despite the construction of four locks and dams on that river in Louisiana and Arkansas in the 1980s. The Ouachita River drainage and a few streams in east-central Missouri are currently the only known spawning areas for A. alabamae in noncoastal regions of the entire Mississippi River basin. Continued survival of the Alabama shad in Arkansas depends on protecting critical spawning and nursery habitats in the Ouachita River system from deleterious alteration and on preserving that migratory species\u27 access to those habitats

    Bi-log-concave distribution functions

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    Nonparametric statistics for distribution functions F or densities f=F' under qualitative shape constraints provides an interesting alternative to classical parametric or entirely nonparametric approaches. We contribute to this area by considering a new shape constraint: F is said to be bi-log-concave, if both log(F) and log(1 - F) are concave. Many commonly considered distributions are compatible with this constraint. For instance, any c.d.f. F with log-concave density f = F' is bi-log-concave. But in contrast to the latter constraint, bi-log-concavity allows for multimodal densities. We provide various characterizations. It is shown that combining any nonparametric confidence band for F with the new shape-constraint leads to substantial improvements, particularly in the tails. To pinpoint this, we show that these confidence bands imply non-trivial confidence bounds for arbitrary moments and the moment generating function of F

    Understanding the National Student Survey: investigations in languages, linguistics and area studies

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    This report is a summary of interviews and focus groups with around 100 students and 50 members of academic staff in departments of languages, linguistics or area studies at nine universities in the UK. In recent years, concerns have been expressed about the ambiguity of some of the statements which students are asked to respond to in the National Student Survey (NSS). This project set out to get a better understanding of how students and staff understand the questions. The interviews and focus groups were carried out by members of academic staff at the nine institutions who each then wrote an individual report of their findings. This summary is designed to enable wider distribution of these findings without identifying individual staff, institutions `or departments
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