3,454 research outputs found

    Effect of Sleep Deprivation and Sleep Recovery on Heart Rate and Heart Rate Variability in Males Versus Females

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    Introduction Elevated heart rate (HR) and low HR variability (HRV) are indicators of increased sympathetic tone and cardiovascular risk. Here, we assess the effect of one night of sleep deprivation and a subsequent night of recovery sleep on HR and HRV in healthy males versus females. Methods Fifty-nine subjects (29.5±8.5y, n=35 female) completed a 4-day/3-night laboratory study. Subjects had a baseline sleep opportunity (22:00–08:00), followed by 38h of sleep deprivation, and a recovery sleep opportunity (22:00–08:00). EKG was monitored via Holter monitors to measure HR and the pNN50 and rMMSD variables of HRV. Time points used for analyses included 09:00–09:20 during a seated task on each day: baseline (1h after waking), sleep deprivation (25h after waking), and recovery (1h after waking). Results There was no significant interaction of day by sex in HR, pNN50, or rMMSD (p\u3e0.05). There was, however, a significant effect of day (p Conclusion The effect of sleep deprivation on HR and HRV indicates a decrease in sympathetic activity, in-line with previous research reporting inhibition of the brain’s arousal centers as a consequence of increasing time awake. Notably, HR and HRV returned to baseline levels following a night of recovery sleep. Despite higher HR and lower HRV in females versus males at baseline, both sexes showed a similar cardiac autonomic response to sleep deprivatio

    Oral antihypertensive therapy for severe hypertension in pregnancy and postpartum: a systematic review.

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    BACKGROUND: Pregnant and postpartum women with severe hypertension are at increased risk of stroke and require blood pressure (BP) reduction. Parenteral antihypertensives have been most commonly studied, but oral agents would be ideal for use in busy and resource-constrained settings. OBJECTIVES: To review systematically, the effectiveness of oral antihypertensive agents for treatment of severe pregnancy/postpartum hypertension. SEARCH STRATEGY: A systematic search of MEDLINE, EMBASE and the Cochrane Library was performed. SELECTION CRITERIA: Randomised controlled trials in pregnancy and postpartum with at least one arm consisting of a single oral antihypertensive agent to treat systolic BP ≥ 160 mmHg and/or diastolic BP ≥ 110 mmHg. DATA COLLECTION AND ANALYSIS: Cochrane RevMan 5.1 was used to calculate relative risk (RR) and weighted mean difference by random effects. MAIN RESULTS: We identified 15 randomised controlled trials (915 women) in pregnancy and one postpartum trial. Most trials in pregnancy compared oral/sublingual nifedipine capsules (8-10 mg) with another agent, usually parenteral hydralazine or labetalol. Nifedipine achieved treatment success in most women, similar to hydralazine (84% with nifedipine; relative risk [RR] 1.07, 95% confidence interval [95% CI] 0.98-1.17) or labetalol (100% with nifedipine; RR 1.02, 95% CI 0.95-1.09). Less than 2% of women treated with nifedipine experienced hypotension. There were no differences in adverse maternal or fetal outcomes. Target BP was achieved ~ 50% of the time with oral labetalol (100 mg) or methyldopa (250 mg) (47% labetelol versus 56% methyldopa; RR 0.85 95% CI 0.54-1.33). CONCLUSIONS: Oral nifedipine, and possibly labetalol and methyldopa, are suitable options for treatment of severe hypertension in pregnancy/postpartum

    A position statement on screening and management of prediabetes in adults in primary care in Australia.

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    Prediabetes has a high prevalence, with early detection essential to facilitate optimal management to prevent the development of conditions such as type 2 diabetes and cardiovascular disease. Prediabetes can include impaired fasting glucose, impaired glucose tolerance and elevated HbA1c. This position statement outlines the approaches to screening and management of prediabetes in primary care. There is good evidence to implement intensive, structured lifestyle interventions for individuals with impaired glucose tolerance. The evidence for those with impaired fasting glucose or elevated HbA1c is less clear, but individuals should still be provided with generalised healthy lifestyle strategies. A multidisciplinary approach is recommended to implement healthy lifestyle changes through education, nutrition and physical activity. Individuals should aim to lose weight (5-10% of body mass) using realistic and sustainable dietary approaches supported by an accredited practising dietitian, where possible. Physical activity and exercise should be used to facilitate weight maintenance and reduce blood glucose. Moderate-vigorous intensity aerobic exercise and resistance training should be prescribed by an accredited exercise physiologist, where possible. When indicated, pharmacotherapy, metabolic surgery and psychosocial care should be considered, in order to enhance the outcomes associated with lifestyle change. Individuals with prediabetes should generally be evaluated annually for their diabetes status

    Developing "smart" tutorial tools to assist students learn calculus, taking account of their changing preferred approaches to learning

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    We present the result of a small study where we investigate what types of resources current students of Mathematics and Mathematics for Engineering prefer for assisting them with their studies of those topics. We found that modern students seem to have a clear preference for on-line resources over traditional textbooks. However, there is currently a lack of good quality resources of that type which allow students to carry-out conventional mathematics exercises on-line and still get appropriate, meaningful and informative feedback on their answers. We then describe our efforts towards addressing this problem through the development of an “intelligent” tutorial system for Calculus which provides feedback tailored to the student’s responses, noting where and how they have made common errors

    Update on the Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II):Statistical analysis plan

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    <p>Abstract</p> <p>Background</p> <p>Previous studies had suggested that the outcome for patients with spontaneous lobar intracerebral haemorrhage (ICH) and no intraventricular haemorrhage (IVH) might be improved with early evacuation of the haematoma. The Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II) set out to establish whether a policy of earlier surgical evacuation of the haematoma in selected patients with spontaneous lobar ICH would improve outcome compared to a policy of initial conservative treatment. It is an international, multi-centre, prospective randomised parallel group trial of early surgery in patients with spontaneous lobar ICH. Outcome is measured at six months via a postal questionnaire.</p> <p>Results</p> <p>Recruitment to the study began on 27 November 2006 and closed on 15 August 2012 by which time 601 patients had been recruited. The protocol was published in <it>Trials</it> (<url>http://www.trialsjournal.com/content/12/1/124/</url>). This update presents the analysis plan for the study without reference to the unblinded data. The trial data will not be unblinded until after follow-up is completed in early 2013. The main trial results will be presented in spring 2013 with the aim to publish in a peer-reviewed journal at the same time.</p> <p>Conclusion</p> <p>The data from the trial will provide evidence on the benefits and risks of early surgery in patients with lobar ICH.</p> <p>Trial registration</p> <p>ISRCTN: ISRCTN22153967</p

    Quantum phase transition in a single-molecule quantum dot

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    Quantum criticality is the intriguing possibility offered by the laws of quantum mechanics when the wave function of a many-particle physical system is forced to evolve continuously between two distinct, competing ground states. This phenomenon, often related to a zero-temperature magnetic phase transition, can be observed in several strongly correlated materials such as heavy fermion compounds or possibly high-temperature superconductors, and is believed to govern many of their fascinating, yet still unexplained properties. In contrast to these bulk materials with very complex electronic structure, artificial nanoscale devices could offer a new and simpler vista to the comprehension of quantum phase transitions. This long-sought possibility is demonstrated by our work in a fullerene molecular junction, where gate voltage induces a crossing of singlet and triplet spin states at zero magnetic field. Electronic tunneling from metallic contacts into the C60\rm{C_{60}} quantum dot provides here the necessary many-body correlations to observe a true quantum critical behavior.Comment: 8 pages, 5 figure

    Tau accumulation in autosomal dominant Alzheimer’s disease: a longitudinal [18F]flortaucipir study

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    Cortical tau accumulation is a key pathological event that partly defines Alzheimer’s disease (AD) onset and is associated with cognitive decline and future disease progression. However, an improved understanding of the timing and pattern of early tau deposition in AD and how this may be tracked in vivo is needed. Data from 59 participants involved in two longitudinal cohort studies of autosomal dominant AD (ADAD) were used to investigate whether tau PET can detect and track presymptomatic change; seven participants were symptomatic, and 52 were asymptomatic but at a 50% risk of carrying a pathogenic mutation. All had baseline flortaucipir (FTP) PET, MRI and clinical assessments; 26 individuals had more than one FTP PET scan. Standardised uptake value ratios (SUVRs) in prespecified regions of interest (ROIs) were obtained using inferior cerebellar grey matter as the reference region. We compared the changes in FTP SUVRs between presymptomatic carriers, symptomatic carriers and non-carriers, adjusting for age, sex and study site. We also investigated the relationship between regional FTP SUVRs and estimated years to/from symptom onset (EYO). Compared to both non-carriers and presymptomatic carriers, FTP SUVRs were significantly higher in symptomatic carriers in all ROIs tested (p 0.05), although increased FTP signal uptake was seen posteriorly in some individuals around the time of expected symptom onset. When we examined the relationship of FTP SUVR with respect to EYO, the earliest significant regional difference between mutation carriers and non-carriers was detected within the precuneus prior to estimated symptom onset in some cases. This study supports preliminary studies suggesting that presymptomatic tau tracer uptake is rare in ADAD. In cases where early uptake was seen, there was often a predilection for posterior regions (the precuneus and post-cingulate) as opposed to the medial temporal lobe, highlighting the importance of examining in vivo tau uptake beyond the confines of traditional Braak staging

    Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management

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    Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems

    How and When Socially Entrepreneurial Nonprofit Organizations Benefit From Adopting Social Alliance Management Routines to Manage Social Alliances?

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    Social alliance is defined as the collaboration between for-profit and nonprofit organizations. Building on the insights derived from the resource-based theory, we develop a conceptual framework to explain how socially entrepreneurial nonprofit organizations (SENPOs) can improve their social alliance performance by adopting strategic alliance management routines. We test our framework using the data collected from 203 UK-based SENPOs in the context of cause-related marketing campaign-derived social alliances. Our results confirm a positive relationship between social alliance management routines and social alliance performance. We also find that relational mechanisms, such as mutual trust, relational embeddedness, and relational commitment, mediate the relationship between social alliance management routines and social alliance performance. Moreover, our findings suggest that different types of social alliance motivation can influence the impact of social alliance management routines on different types of the relational mechanisms. In general, we demonstrate that SENPOs can benefit from adopting social alliance management routines and, in addition, highlight how and when the social alliance management routines–social alliance performance relationship might be shaped. Our study offers important academic and managerial implications, and points out future research directions

    Combining mouse and keyboard events with higher level desktop actions to detect mild cognitive impairment

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    We present a desktop monitoring application that combines keyboard, mouse, desktop and application-level activities. It has been developed to discover differences in cognitive functioning amongst older computer users indicative of mild cognitive impairment (MCI). Following requirements capture from clinical domain experts, the tool collects all Microsoft Windows events deemed potentially useful for detecting early clinical indicators of dementia, with a view to further analysis to determine the most pertinent. Further requirements capture from potential end-users has resulted in a system that has little impact on users? daily activities and ensures data security from initial recording of events through to data analysis. We describe two experiments: firstly, volunteers were asked to perform a short set of known tasks; the second (ongoing) experiment is a longitudinal study, with the software currently successfully running on participants? computers
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