63 research outputs found

    Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system

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    Recent work in the literature has shown that the one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., at the Lagrangian libration points of stable equilibrium the planetoid is not exactly at equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical calculation by exploiting the full theory of the quintic equation, i.e., its reduction to Bring-Jerrard form and the resulting expression of roots in terms of generalized hypergeometric functions. By performing the numerical analysis of the exact formulas for the roots, we confirm and slightly improve the theoretical evaluation of quantum corrected coordinates of Lagrangian libration points of stable equilibrium. Second, we prove in detail that also for collinear Lagrangian points the quantum corrections are of the same order of magnitude in the Earth-Moon system. Third, we discuss the prospects to measure, with the help of laser ranging, the above departure from the equilateral triangle picture, which is a challenging task. On the other hand, a modern version of the planetoid is the solar sail, and much progress has been made, in recent years, on the displaced periodic orbits of solar sails at all libration points, both stable and unstable. The present paper investigates therefore, eventually, a restricted three-body problem involving Earth, Moon and a solar sail. By taking into account the one-loop quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist

    Measurement properties of the Minimal Insomnia Symptom Scale (MISS) in an elderly population in Sweden

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    <p>Abstract</p> <p>Background</p> <p>Insomnia is common among elderly people and associated with poor health. The Minimal Insomnia Symptom Scale (MISS) is a three item screening instrument that has been found to be psychometrically sound and capable of identifying insomnia in the general population (20-64 years). However, its measurement properties have not been studied in an elderly population. Our aim was to test the measurement properties of the MISS among people aged 65 + in Sweden, by replicating the original study in an elderly sample.</p> <p>Methods</p> <p>Data from a cross-sectional survey of 548 elderly individuals were analysed in terms of assumptions of summation of items, floor/ceiling effects, reliability and optimal cut-off score by means of ROC-curve analysis and compared with self-reported insomnia criteria.</p> <p>Results</p> <p>Corrected item-total correlations ranged between 0.64-0.70, floor/ceiling effects were 6.6/0.6% and reliability was 0.81. ROC analysis identified the optimal cut-off score as ≥7 (sensitivity, 0.93; specificity, 0.84; positive/negative predictive values, 0.256/0.995). Using this cut-off score, the prevalence of insomnia in the study sample was 21.7% and most frequent among women and the oldest old.</p> <p>Conclusions</p> <p>Data support the measurement properties of the MISS as a possible insomnia screening instrument for elderly persons. This study make evident that the MISS is useful for identifying elderly people with insomnia-like sleep problems. Further studies are needed to assess its usefulness in identifying clinically defined insomnia.</p

    A three-group study, internet-based, face-to-face based and standard- management after acute whiplash associated disorders (WAD) – choosing the most efficient and cost-effective treatment: study protocol of a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>The management of Whiplash Associated Disorders is one of the most complicated challenges with high expenses for the health care system and society. There are still no general guidelines or scientific documentation to unequivocally support any single treatment for acute care following whiplash injury.</p> <p>The main purpose of this study is to try a new behavioural medicine intervention strategy at acute phase aimed to reduce the number of patients who have persistent problems after the whiplash injury. The goal is also to identify which of three different interventions that is most cost-effective for patients with Whiplash Associated Disorders. In this study we are controlling for two factors. First, the effect of behavioural medicine approach is compared with standard care. Second, the manner in which the behavioural medicine treatment is administered, Internet or face-to-face, is evaluated in it's effectiveness and cost-effectiveness.</p> <p>Methods/Design</p> <p>The study is a randomized, prospective, experimental three-group study with analyses of cost-effectiveness up to two-years follow-up. <it>Internet – based programme </it>and <it>face-to-face group treatment programme </it>are compared to <it>standard-treatment </it>only. Patient follow-ups take place three, six, twelve and 24 months, that is, short-term as well as long-term effects are evaluated. Patients will be enrolled via the emergency ward during the first week after the accident.</p> <p>Discussion</p> <p>This new self-help management will concentrate to those psychosocial factors that are shown to be predictive in long-term problems in Whiplash Associated Disorders, i.e. the importance of self-efficacy, fear of movement, and the significance of catastrophizing as a coping strategy for restoring and sustaining activities of daily life. Within the framework of this project, we will develop, broaden and evaluate current physical therapy treatment methods for acute Whiplash Associated Disorders. The project will contribute to the creation of a cost-effective behavioural medicine approach to management of acute Whiplash Associated Disorders. The results of this study will answer an important question; on what extent and how should these patients be treated at acute stage and how much does the best management cost.</p> <p>Trial registration number</p> <p>Current Controlled Trials ISRCTN61531337</p

    Genetic variation and exercise-induced muscle damage: implications for athletic performance, injury and ageing.

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    Prolonged unaccustomed exercise involving muscle lengthening (eccentric) actions can result in ultrastructural muscle disruption, impaired excitation-contraction coupling, inflammation and muscle protein degradation. This process is associated with delayed onset muscle soreness and is referred to as exercise-induced muscle damage. Although a certain amount of muscle damage may be necessary for adaptation to occur, excessive damage or inadequate recovery from exercise-induced muscle damage can increase injury risk, particularly in older individuals, who experience more damage and require longer to recover from muscle damaging exercise than younger adults. Furthermore, it is apparent that inter-individual variation exists in the response to exercise-induced muscle damage, and there is evidence that genetic variability may play a key role. Although this area of research is in its infancy, certain gene variations, or polymorphisms have been associated with exercise-induced muscle damage (i.e. individuals with certain genotypes experience greater muscle damage, and require longer recovery, following strenuous exercise). These polymorphisms include ACTN3 (R577X, rs1815739), TNF (-308 G>A, rs1800629), IL6 (-174 G>C, rs1800795), and IGF2 (ApaI, 17200 G>A, rs680). Knowing how someone is likely to respond to a particular type of exercise could help coaches/practitioners individualise the exercise training of their athletes/patients, thus maximising recovery and adaptation, while reducing overload-associated injury risk. The purpose of this review is to provide a critical analysis of the literature concerning gene polymorphisms associated with exercise-induced muscle damage, both in young and older individuals, and to highlight the potential mechanisms underpinning these associations, thus providing a better understanding of exercise-induced muscle damage

    Temporal trends in fetal mortality at and beyond term and induction of labor in Germany 2005-2012 : data from German routine perinatal monitoring

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    Purpose: While a variety of factors may play a role in fetal and neonatal deaths, postmaturity as a cause of stillbirth remains a topic of debate. It still is unclear, whether induction of labor at a particular gestational age may prevent fetal deaths. Methods: A multidisciplinary working group was granted access to the most recent set of relevant German routine perinatal data, comprising all 5,291,011 hospital births from 2005 to 2012. We analyzed correlations in rates of induction of labor (IOL), perinatal mortality (in particular stillbirths) at different gestational ages, and fetal morbidity. Correlations were tested with Pearson's product-moment analysis (α = 5 %). All computations were performed with SPSS version 22. Results: Induction rates rose significantly from 16.5 to 21.9 % (r = 0.98; p \ 0.001). There were no significant changes in stillbirth rates (0.28-0.35 per 100 births; r = 0.045; p = 0.806). Stillbirth rates 2009-2012 remained stable in all gestational age groups irrespective of induction. Fetal morbidity (one or more ICD-10 codes) rose significantly during 2005–2012. This was true for both children with (from 33 to 37 %, r = 0.784, p \ 0.001) and without (from 25 to 31 %, (r = 0.920, p \ 0.001) IOL. Conclusions: An increase in IOL at term is not associated with a decline in perinatal mortality. Perinatal morbidity increased with and without indiction of labor
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