595 research outputs found

    Estimation of badger abundance using faecal DNA typing

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    1.Wildlife management and conservation programmes often require accurate information on population density, but this can be difficult to obtain, particularly when the species in question is nocturnal or cryptic. Badger populations in Britain are of intense management interest because they are a wildlife reservoir host of bovine tuberculosis (TB). Attempts to manage this infection in badgers, whether by population control or vaccination, require reliable methods of estimating population size. In addition, such estimates are also required to support research into badger ecology and TB epidemiology. Currently, the most accurate estimates of local badger population size are obtained from labour-intensive and time-consuming mark–recapture studies. 2. In recent years, DNA has been successfully extracted from the faeces of certain mammals, and used to generate a genetic profile of the defecating individual. Here we report on an application of this technology to estimate badger abundance.3.Faecal samples were collected on 10 consecutive days from every freshly deposited dropping at latrine sites close to occupied setts in three badger social groups. Badger DNA was extracted from 89% of samples, and 20 different individuals were reliably identified. The genotypes derived from the faecal samples were compared with those obtained from blood or samples from badgers live trapped at the same setts.4.The faecal genotypes from badgers with known trap histories revealed that latrines were used equally by males and females, and by badgers ranging in age from cubs(< 1 year old) to 9 years old. Individual badgers used the latrines on between one and six different nights. Rarefaction analysis produced abundance estimates that closely matched those obtained from live trapping. 5.Synthesis and applications. Systematic sampling and genetic typing of fresh faeces from badger latrines can provide data that can be used to estimate abundance accurately.This approach requires considerably less human resources than repeated live trapping and mark–recapture. The technique may be valuable for future badger research and management in relation to bovine TB, where accurate estimates of abundance at a local scale are required

    The diagnostic accuracy of cross-sectional imaging for detecting acute scaphoid fractures in children: a systematic review

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    OBJECTIVE: To determine the diagnostic accuracy of cross-sectional imaging for the diagnosis of acute scaphoid fractures in children. METHODS: A systematic review of Medline, Embase and Cochrane databases between 1980 and July 2017 was independently performed by two observers. Criteria for study inclusion in a meta-analysis and assessment of the quality of such studies using the QADAS tool, were predetermined. RESULTS: No studies were eligible for inclusion in a meta-analysis. Three studies (of low quality when assessed against the STARD guidelines for reporting of studies of diagnostic accuracy) assessed MRI (performed between Days 2 and 10 after acute injury) for the diagnosis of scaphoid fractures in a total of 119 children (age range 6 to 16 years). Study 1 (45 children) reported inter-observer reliability of radiographs and MRI of 0.53 and 0.95 respectively. Study 3 (18 children) reported a negative predictive value of MRI (even as early as Day 2), of 100%. No measure of diagnostic accuracy or observer reliability was reported in Study 2 (56 children). In all 3 studies, MRI identified more scaphoid fractures (and other carpal injuries) than radiographs. Study 3 showed that follow-up MRI between Days 38 and 45 added no new information compared to initial MRI. CONCLUSION: Based on a systematic review of the literature, there is currently no evidence on which to suggest an imaging protocol for suspected scaphoid fracture in children. Until such evidence is available, existing guidelines (which are based on expert opinion from adult studies) should be followed. Advances in Knowledge 1. There is low quality evidence regarding the diagnostic accuracy of cross-sectional imaging for suspected scaphoid fractures in children and no evidence on which to propose an optimal imaging strategy. 2. Until such evidence is available, current guidelines (based predominantly on findings in adults and expert opinion) should be followed

    Vitamin D intake, calcium intake and physical activity among children with wrist and ankle injuries and the association with fracture risk.

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    BACKGROUND:: Several studies have revealed a substantial increase in the incidence of fractures in children in the past few decades. AIM:: To assess the strength of the association between suggested risk factors and fracture prevalence in children. METHOD:: A cross sectional observational study. Children aged 6-15 years and their guardians presenting to the Emergency Department of a single tertiary paediatric hospital were recruited. Self-reported data on vitamin D intake, calcium intake and physical activity were collected. All participants had a radiograph of their injured limb reported by a consultant radiologist, on the basis of which they were classified into fracture or no fracture groups. Statistical analysis included descriptive statistics and binary logistic regression. RESULTS:: Of the 130 patients recruited, 53 (41%) had sustained a fracture. The overwhelming majority of children (98%) did not consume the recommended daily dietary amount of vitamin D (400 IU/day). Low calcium intake and low levels of physical activity were also ascertained. However, there were no significant differences between fracture and no fracture groups for vitamin D intake, calcium intake or physical activity. Both site of injury (wrist) and sex (male) were associated with increased fracture risk ( p = 0.001 and p = 0.05, respectively). Logistic regression showed a statistically significant relationship between calcium intake and fracture risk (every additional unit of calcium consumption (mg/day) decreased the likelihood of fracture by 0.002, 95% confidence interval, 0.001-0.003). CONCLUSIONS:: Low dietary intake of calcium and vitamin D and low levels of physical activity were evident. Fracture risk was significantly associated with reduced calcium intake but showed no association with vitamin D intake or physical activity

    Calcium Intake From Diet and Supplements and the Risk of Coronary Artery Calcification and its Progression Among Older Adults: 10‐Year Follow‐up of the Multi‐Ethnic Study of Atherosclerosis (MESA)

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    BACKGROUND: Recent randomized data suggest that calcium supplements may be associated with increased risk of cardiovascular disease (CVD) events. Using a longitudinal cohort study, we assessed the association between calcium intake, from both foods and supplements, and atherosclerosis, as measured by coronary artery calcification (CAC). METHODS AND RESULTS: We studied 5448 adults free of clinically diagnosed CVD (52% female; aged 45-84 years) from the Multi-Ethnic Study of Atherosclerosis. Baseline total calcium intake was assessed from diet (using a food frequency questionnaire) and calcium supplements (by a medication inventory) and categorized into quintiles. Baseline CAC was measured by computed tomography, and CAC measurements were repeated in 2742 participants ≈10 years later. At baseline, mean calcium intakes across quintiles were 313.3, 540.3, 783.0, 1168.9, and 2157.4 mg/day. Women had higher calcium intakes than men. After adjustment for potential confounders, among 1567 participants without baseline CAC, the relative risk (RR) of developing incident CAC over 10 years, by quintile 1 to 5 of calcium intake, were 1 (reference), 0.95 (0.79-1.14), 1.02 (0.85-1.23), 0.86 (0.69-1.05), and 0.73 (0.57-0.93). After accounting for total calcium intake, calcium supplement use was associated with increased risk for incident CAC (RR=1.22 [1.07-1.39]). No relation was found between baseline calcium intake and 10-year changes in log-transformed CAC among those participants with baseline CAC >0. CONCLUSIONS: High total calcium intake was associated with a decreased risk of incident atherosclerosis over long-term follow-up, particularly if achieved without supplement use. However, calcium supplement use may increase the risk for incident CAC

    Older parents of people who have a learning disability : perceptions of future accomodation needs

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    The aim of this qualitative study was to provide an insight into the perceptions of older parents of learning disabled people on the future accommodation needs of their adult children. Semi-structured interviews were used to seek parental awareness of residential options available, concerns in relation to future accommodation and the preferred accommodation options for their offspring. Four couples who shared the family home with an adult who has a learning disability took part in the study and data was analysed using a step by step form of content analysis as described by Burnard (1991). Emergent themes from transcripts were then organised into main categories The results of this study suggest that older parents are dissatisfied with both statutory and private services, that they have concerns for their non-disabled children and their own ageing. Being a parent to a person who has a learning disability is seen to be a difficult task and yet parents may want to provide support at home for as long a possible. Of the parents who participated in this study, three couples wanted to maintain their adult child at home for as long as possible and the parents who were actively seeking accommodation outside the family home expected to be involved in all aspects of their daughter�s care for the long term future

    A theoretical and empirical investigation of nutritional label use

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    Due in part to increasing diet-related health problems caused, among others, by obesity, nutritional labelling has been considered important, mainly because it can provide consumers with information that can be used to make informed and healthier food choices. Several studies have focused on the empirical perspective of nutritional label use. None of these studies, however, have focused on developing a theoretical economic model that would adequately describe nutritional label use based on a utility theoretic framework. We attempt to fill this void by developing a simple theoretical model of nutritional label use, incorporating the time a consumer spends reading labels as part of the food choice process. The demand equations of the model are then empirically tested. Results suggest the significant role of several variables that flow directly from the model which, to our knowledge, have not been used in any previous empirical work

    Thermal Density Functional Theory in Context

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    This chapter introduces thermal density functional theory, starting from the ground-state theory and assuming a background in quantum mechanics and statistical mechanics. We review the foundations of density functional theory (DFT) by illustrating some of its key reformulations. The basics of DFT for thermal ensembles are explained in this context, as are tools useful for analysis and development of approximations. We close by discussing some key ideas relating thermal DFT and the ground state. This review emphasizes thermal DFT's strengths as a consistent and general framework.Comment: Submitted to Spring Verlag as chapter in "Computational Challenges in Warm Dense Matter", F. Graziani et al. ed

    Comparative study of density functional theories of the exchange-correlation hole and energy in silicon

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    We present a detailed study of the exchange-correlation hole and exchange-correlation energy per particle in the Si crystal as calculated by the Variational Monte Carlo method and predicted by various density functional models. Nonlocal density averaging methods prove to be successful in correcting severe errors in the local density approximation (LDA) at low densities where the density changes dramatically over the correlation length of the LDA hole, but fail to provide systematic improvements at higher densities where the effects of density inhomogeneity are more subtle. Exchange and correlation considered separately show a sensitivity to the nonlocal semiconductor crystal environment, particularly within the Si bond, which is not predicted by the nonlocal approaches based on density averaging. The exchange hole is well described by a bonding orbital picture, while the correlation hole has a significant component due to the polarization of the nearby bonds, which partially screens out the anisotropy in the exchange hole.Comment: 16 pages, 5 figures, RevTeX, added conten
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