755 research outputs found

    Genetic Factors Associated with Exercise Performance in Atmospheric Hypoxia

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    Background and Objective ‘Natural selection’ has been shown to have enriched the genomes of high-altitude native populations with genetic variants of advantage in this hostile hypoxic environment. In lowlanders who ascend to altitude, genetic factors may also contribute to the substantial interindividual variation in exercise performance noted at altitude. We performed a systematic literature review to identify genetic variants of possible influence on human hypoxic exercise performance, commenting on the strength of any identified associations. Criteria for considering studies for this review All studies of the association of genetic factors with human hypoxic exercise performance, whether at sea level using ‘nitrogen dilution of oxygen’ (normobaric hypoxia), or at altitude or in low-pressure chambers (field or chamber hypobaric hypoxia, respectively) were sought for review. Search strategy for identification of studies Two electronic databases were searched (Ovid MEDLINE, Embase) up to 31 January 2014. We also searched the reference lists of relevant articles for eligible studies. All studies published in English were included, as were studies in any language for which the abstract was available in English. Data collection and analysis Studies were selected and data extracted independently by two reviewers. Differences regarding study inclusion were resolved through discussion. The quality of each study was assessed using a scoring system based on published guidelines for conducting and reporting genetic association studies. Results A total of 11 studies met all inclusion criteria and were included in the review. Subject numbers ranged from 20 to 1,931 and consisted of healthy individuals in all cases. The maximum altitude of exposure ranged from 2,690 to 8,848 m. The exercise performance phenotypes assessed were mountaineering performance (n = 5), running performance (n = 2), and maximum oxygen consumption (V ˙ V˙ O2max) (n = 4). In total, 13 genetic polymorphisms were studied, four of which were associated with hypoxic exercise performance. The adenosine monophosphate deaminase (AMPD1) C34T (rs17602729), beta2-adrenergic receptor (ADRB2) Gly16Arg single nucleotide polymorphism (SNP) (rs1042713), and androgen receptor CAG repeat polymorphisms were associated with altitude performance in one study, and the angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) (rs4646994) polymorphism was associated with performance in three studies. The median score achieved in the study quality analysis was 6 out of 10 for case–control studies, 8 out of 10 for cohort studies with a discrete outcome, 6 out of 9 for cohort studies with a continuous outcome, and 4.5 out of 8 for genetic admixture studies. Conclusion The small number of articles identified in the current review and the limited number of polymorphisms studied in total highlights that the influence of genetic factors on exercise performance in hypoxia has not been studied in depth, which precludes firm conclusions being drawn. Support for the association between the ACE-I allele and improved high-altitude performance was the strongest, with three studies identifying a relationship. Analysis of study quality highlights the need for future studies in this field to improve the conduct and reporting of genetic association studies

    Is metal theft committed by organized crime groups, and why does it matter?

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    Using the example of metal theft in the United Kingdom, this study used mixed methods to evaluate the accuracy of police estimates of the involvement of organised crime groups (OCGs) in crime. Police estimate that 20-30% of metal theft is committed by OCGs, but this study found that only 0.5% of metal thieves had previous convictions for offences related to OCGs, that only 1.3% were linked to OCGs by intelligence information, that metal thieves typically offended close to their homes and that almost no metal thefts involved sophisticated offence methods. It appears that police may over-estimate the involvement of OCGs in some types of crime. The reasons for and consequences of this over-estimation are discussed

    Options for early breast cancer follow-up in primary and secondary care : a systematic review

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    Background Both incidence of breast cancer and survival have increased in recent years and there is a need to review follow up strategies. This study aims to assess the evidence for benefits of follow-up in different settings for women who have had treatment for early breast cancer. Method A systematic review to identify key criteria for follow up and then address research questions. Key criteria were: 1) Risk of second breast cancer over time - incidence compared to general population. 2) Incidence and method of detection of local recurrence and second ipsi and contra-lateral breast cancer. 3) Level 1–4 evidence of the benefits of hospital or alternative setting follow-up for survival and well-being. Data sources to identify criteria were MEDLINE, EMBASE, AMED, CINAHL, PSYCHINFO, ZETOC, Health Management Information Consortium, Science Direct. For the systematic review to address research questions searches were performed using MEDLINE (2011). Studies included were population studies using cancer registry data for incidence of new cancers, cohort studies with long term follow up for recurrence and detection of new primaries and RCTs not restricted to special populations for trials of alternative follow up and lifestyle interventions. Results Women who have had breast cancer have an increased risk of a second primary breast cancer for at least 20 years compared to the general population. Mammographically detected local recurrences or those detected by women themselves gave better survival than those detected by clinical examination. Follow up in alternative settings to the specialist clinic is acceptable to women but trials are underpowered for survival. Conclusions Long term support, surveillance mammography and fast access to medical treatment at point of need may be better than hospital based surveillance limited to five years but further large, randomised controlled trials are needed

    Undergraduate mental health issues: the challenge of the second year of study

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    Background: Student mental health is a global issue. Macaskill (2012) reported that the second year was associated with the most significant increases in psychiatric symptoms in UK students. Qualitative data were collected to explore this further. Method: Twenty-three second year undergraduate students were interviewed using a narrative interviewing method to explore their experience of their second year of study. They also completed the GHQ-28. Students were grouped according to their psychiatric caseness scores, giving two groups, a well group with scores ≀ 5 and a clinical case group with scores ≄6 and their interview data were compared. Results: Using thematic analysis, various themes and subthemes were identified. While both groups identified the same issues namely, the first year concerns impacting on the second year, course issues, careers and future employability and student debt, the groups reported very different coping styles. Conclusion: There were shared anxieties across both groups. The majority related to institutional practices and the unintended impact they may be having on student mental health. While specialist interventions would help the clinical caseness group, arguably the anxiety levels of both groups would benefit equally from relatively easy to implement, inexpensive institutional changes and/or additions to current practices in universities

    Feasibility study of a Behavioural Intervention for Opioid Reduction (BIOR) for patients with chronic non-cancer pain in primary care: a protocol

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    Introduction Around 30%–50% of adults suffer moderate to severe chronic pain not caused by cancer. Significant numbers are treated with opioids which over time may cease to be effective and produce side effects (eg, nausea, drowsiness and constipation). Stopping taking opioids abruptly can cause unpleasant withdrawal effects. Tapering in small steps is recommended, though some patients might struggle and need support, particularly if they have limited access to pain management alternatives. Awareness of the potential risks as well as benefits of tapering should be explored with patients. Methods and analysis A randomised controlled pilot feasibility study to investigate the effectiveness and feasibility of reducing high doses of opioids through a tapering protocol, education and support in primary care. Working with NHS Knowsley Place, we will identify patients taking 50mg or above morphine equivalent dose of opioids per day to be randomly allocated to either the tapering group or tapering with support group. At an initial joint appointment with a pain consultant and General Practitioner (GP) GP tapering will be discussed and negotiated. Both groups will have their opioid reduced by 10% per week. The taper with support group will have access to additional support, including motivational counselling, realistic goal setting and a toolkit of resources to promote self-management. Some patients will successfully reduce their dose each week. For others, this may be more difficult, and the tapering reduction will be adjusted to 10% per fortnight. We assess opioid use, pain and quality of life in both groups at the start and end of the study to determine which intervention works best to support people with chronic pain who wish to stop taking opioids. Ethics and dissemination The Behavioural Intervention for Opioid Reduction feasibility study has been granted full approval by Liverpool Central Research Ethics Committee on 7 April 2022 (22/NW/0047). The current protocol version is V.1.1, date 6 July 2022. Results will be published in peer-reviewed journals and disseminated to patient stakeholders in a lay summary report available on the project website and in participating GP surgeries

    Lambda and Antilambda polarization from deep inelastic muon scattering

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    We report results of the first measurements of Lambda and Antilambda polarization produced in deep inelastic polarized muon scattering on the nucleon. The results are consistent with an expected trend towards positive polarization with increasing x_F. The polarizations of Lambda and Antilambda appear to have opposite signs. A large negative polarization for Lambda at low positive x_F is observed and is not explained by existing models.A possible interpretation is presented.Comment: 9 pages, 2 figure

    A faster way to the CSIDH

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    Recently Castryck, Lange, Martindale, Panny, and Renes published CSIDH, a new key exchange scheme using supersingular elliptic curve isogenies. Due to its small key sizes, and the possibility of a non-interactive and a static-static key exchange, CSIDH seems very interesting for practical applications. However, the performance is rather slow. Therefore, we employ some techniques to speed up the algorithms, mainly by restructuring the elliptic curve point multiplications and by using twisted Edwards curves in the isogeny image curve computations, yielding a speed-up factor of 1.33 in comparison to the implementation of Castryck et al. Furthermore, we suggest techniques for constant-time implementations

    Evolutionary and pulsational properties of white dwarf stars

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    Abridged. White dwarf stars are the final evolutionary stage of the vast majority of stars, including our Sun. The study of white dwarfs has potential applications to different fields of astrophysics. In particular, they can be used as independent reliable cosmic clocks, and can also provide valuable information about the fundamental parameters of a wide variety of stellar populations, like our Galaxy and open and globular clusters. In addition, the high densities and temperatures characterizing white dwarfs allow to use these stars as cosmic laboratories for studying physical processes under extreme conditions that cannot be achieved in terrestrial laboratories. They can be used to constrain fundamental properties of elementary particles such as axions and neutrinos, and to study problems related to the variation of fundamental constants. In this work, we review the essentials of the physics of white dwarf stars. Special emphasis is placed on the physical processes that lead to the formation of white dwarfs as well as on the different energy sources and processes responsible for chemical abundance changes that occur along their evolution. Moreover, in the course of their lives, white dwarfs cross different pulsational instability strips. The existence of these instability strips provides astronomers with an unique opportunity to peer into their internal structure that would otherwise remain hidden from observers. We will show that this allows to measure with unprecedented precision the stellar masses and to infer their envelope thicknesses, to probe the core chemical stratification, and to detect rotation rates and magnetic fields. Consequently, in this work, we also review the pulsational properties of white dwarfs and the most recent applications of white dwarf asteroseismology.Comment: 85 pages, 28 figures. To be published in The Astronomy and Astrophysics Revie

    The cost effectiveness of REACH-HF and home-based cardiac rehabilitation compared with the usual medical care for heart failure with reduced ejection fraction:a decision model-based analysis

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    This is the final version. Available from Sage Publications via the DOI in this record.Background The REACH-HF (Rehabilitation EnAblement in CHronic Heart Failure) trial found that the REACH-HF home-based cardiac rehabilitation intervention resulted in a clinically meaningful improvement in disease-specific health-related quality of life in patients with reduced ejection fraction heart failure (HFrEF). The aims of this study were to assess the long-term cost-effectiveness of the addition of REACH-HF intervention or home-based cardiac rehabilitation to usual care compared with usual care alone in patients with HFrEF. Design and methods A Markov model was developed using a patient lifetime horizon and integrating evidence from the REACH-HF trial, a systematic review/meta-analysis of randomised trials, estimates of mortality and hospital admission and UK costs at 2015/2016 prices. Taking a UK National Health and Personal Social Services perspective we report the incremental cost per quality-adjusted life-year (QALY) gained, assessing uncertainty using probabilistic and deterministic sensitivity analyses. Results In base case analysis, the REACH-HF intervention was associated with per patient mean QALY gain of 0.23 and an increased mean cost of ÂŁ400 compared with usual care, resulting in a cost per QALY gained of ÂŁ1720. Probabilistic sensitivity analysis indicated a 78% probability that REACH-HF is cost effective versus usual care at a threshold of ÂŁ20,000 per QALY gained. Results were similar for home-based cardiac rehabilitation versus usual care. Sensitivity analyses indicate the findings to be robust to changes in model assumptions and parameters. Conclusions Our cost-utility analyses indicate that the addition of the REACH-HF intervention and home-based cardiac rehabilitation programmes are likely to be cost-effective treatment options versus usual care alone in patients with HFrEF.National Institute for Health Research (NIHR

    Interaction Between Convection and Pulsation

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    This article reviews our current understanding of modelling convection dynamics in stars. Several semi-analytical time-dependent convection models have been proposed for pulsating one-dimensional stellar structures with different formulations for how the convective turbulent velocity field couples with the global stellar oscillations. In this review we put emphasis on two, widely used, time-dependent convection formulations for estimating pulsation properties in one-dimensional stellar models. Applications to pulsating stars are presented with results for oscillation properties, such as the effects of convection dynamics on the oscillation frequencies, or the stability of pulsation modes, in classical pulsators and in stars supporting solar-type oscillations.Comment: Invited review article for Living Reviews in Solar Physics. 88 pages, 14 figure
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