242 research outputs found
Theory of Systematic Computational Error in Free Energy Differences
Systematic inaccuracy is inherent in any computational estimate of a
non-linear average, due to the availability of only a finite number of data
values, N. Free energy differences (DF) between two states or systems are
critically important examples of such averages in physical, chemical and
biological settings. Previous work has demonstrated, empirically, that the
``finite-sampling error'' can be very large -- many times kT -- in DF estimates
for simple molecular systems. Here, we present a theoretical description of the
inaccuracy, including the exact solution of a sample problem, the precise
asymptotic behavior in terms of 1/N for large N, the identification of
universal law, and numerical illustrations. The theory relies on corrections to
the central and other limit theorems, and thus a role is played by stable
(Levy) probability distributions.Comment: 5 pages, 4 figure
Development of a CsI Calorimeter for the Compton-Pair (ComPair) Balloon-Borne Gamma-Ray Telescope
There is a growing interest in astrophysics to fill in the observational
gamma-ray MeV gap. We, therefore, developed a CsI:Tl calorimeter prototype as a
subsystem to a balloon-based Compton and Pair-production telescope known as
ComPair. ComPair is a technology demonstrator for a gamma-ray telescope in the
MeV range that is comprised of 4 subsystems: the double-sided silicon detector,
virtual Frisch grid CdZnTe, CsI calorimeter, and a plastic-based
anti-coincidence detector. The prototype CsI calorimeter is composed of thirty
CsI logs, each with a geometry of .
The logs are arranged in a hodoscopic fashion with 6 in a row that alternate
directions in each layer. Each log has a resolution of around
full-width-at-half-maximum (FWHM) at with a dynamic energy
range of around . A array of
SensL J-series SiPMs read out each end of the log to estimate the depth of
interaction and energy deposition with signals read out with an IDEAS ROSSPAD.
We also utilize an Arduino to synchronize with the other ComPair subsystems
that comprise the full telescope. This work presents the development and
performance of the calorimeter, its testing in thermal and vacuum conditions,
and results from irradiation by monoenergetic gamma-ray
beams. The CsI calorimeter will fly onboard ComPair as a balloon experiment in
the summer of 2023
Mediation in the Law Curriculum
Cited by Lord Neuberger in ‘Educating Future Mediators’ at the 4th Civil Mediation Council National Conference, May 201
Efficient Dynamic Importance Sampling of Rare Events in One Dimension
Exploiting stochastic path integral theory, we obtain \emph{by simulation}
substantial gains in efficiency for the computation of reaction rates in
one-dimensional, bistable, overdamped stochastic systems. Using a well-defined
measure of efficiency, we compare implementations of ``Dynamic Importance
Sampling'' (DIMS) methods to unbiased simulation. The best DIMS algorithms are
shown to increase efficiency by factors of approximately 20 for a
barrier height and 300 for , compared to unbiased simulation. The
gains result from close emulation of natural (unbiased), instanton-like
crossing events with artificially decreased waiting times between events that
are corrected for in rate calculations. The artificial crossing events are
generated using the closed-form solution to the most probable crossing event
described by the Onsager-Machlup action. While the best biasing methods require
the second derivative of the potential (resulting from the ``Jacobian'' term in
the action, which is discussed at length), algorithms employing solely the
first derivative do nearly as well. We discuss the importance of
one-dimensional models to larger systems, and suggest extensions to
higher-dimensional systems.Comment: version to be published in Phys. Rev.
Studying the association between musculoskeletal disorders, quality of life and mental health. A primary care pilot study in rural Crete, Greece
<p>Abstract</p> <p>Background</p> <p>The burden of musculoskeletal disorders (MSD) on the general health and well-being of the population has been documented in various studies. The objective of this study was to explore the association between MSD and the quality of life and mental health of patients and to discuss issues concerning care seeking patterns in rural Greece.</p> <p>Methods</p> <p>Patients registered at one rural Primary Care Centre (PCC) in Crete were invited to complete the Nordic Musculoskeletal Questionnaire (NMQ) for the analysis of musculoskeletal symptoms, together with validated instruments for measuring health related quality of life (SF-36) and mental distress (GHQ-28).</p> <p>Results</p> <p>The prevalence rate of MSD was found to be 71.2%, with low back and knee pain being the most common symptoms. Most conditions significantly impaired the quality of life, especially the physical dimensions of SF-36. Depression was strongly correlated to most MSD (<it>p </it>< 0.001). Multiple logistic analyses revealed that patients who consulted the PCC due to MSD were likely to have more mental distress or impaired physical functioning compared to those who did not.</p> <p>Conclusion</p> <p>Musculoskeletal disorders were common in patients attending the rural PCC of this study and were associated with a poor quality of life and mental distress that affected their consultation behaviour.</p
In search of the authentic nation: landscape and national identity in Canada and Switzerland
While the study of nationalism and national identity has flourished in the last decade, little attention has been devoted to the conditions under which natural environments acquire significance in definitions of nationhood. This article examines the identity-forming role of landscape depictions in two polyethnic nation-states: Canada and Switzerland. Two types of geographical national identity are identified. The first – what we call the ‘nationalisation of nature’– portrays zarticular landscapes as expressions of national authenticity. The second pattern – what we refer to as the ‘naturalisation of the nation’– rests upon a notion of geographical determinism that depicts specific landscapes as forces capable of determining national identity. The authors offer two reasons why the second pattern came to prevail in the cases under consideration: (1) the affinity between wild landscape and the Romantic ideal of pure, rugged nature, and (2) a divergence between the nationalist ideal of ethnic homogeneity and the polyethnic composition of the two societies under consideration
Rationale, design and conduct of a comprehensive evaluation of a primary care based intervention to improve the quality of life of osteoarthritis patients. The PraxArt-project: a cluster randomized controlled trial [ISRCTN87252339]
BACKGROUND: Osteoarthritis (OA) has a high prevalence in primary care. Conservative, guideline orientated approaches aiming at improving pain treatment and increasing physical activity, have been proven to be effective in several contexts outside the primary care setting, as for instance the Arthritis Self management Programs (ASMPs). But it remains unclear if these comprehensive evidence based approaches can improve patients' quality of life if they are provided in a primary care setting. METHODS/DESIGN: PraxArt is a cluster randomised controlled trial with GPs as the unit of randomisation. The aim of the study is to evaluate the impact of a comprehensive evidence based medical education of GPs on individual care and patients' quality of life. 75 GPs were randomised either to intervention group I or II or to a control group. Each GP will include 15 patients suffering from osteoarthritis according to the criteria of ACR. In intervention group I GPs will receive medical education and patient education leaflets including a physical exercise program. In intervention group II the same is provided, but in addition a practice nurse will be trained to monitor via monthly telephone calls adherence to GPs prescriptions and advices and ask about increasing pain and possible side effects of medication. In the control group no intervention will be applied at all. Main outcome measurement for patients' QoL is the GERMAN-AIMS2-SF questionnaire. In addition data about patients' satisfaction (using a modified EUROPEP-tool), medication, health care utilization, comorbidity, physical activity and depression (using PHQ-9) will be retrieved. Measurements (pre data collection) will take place in months I-III, starting in June 2005. Post data collection will be performed after 6 months. DISCUSSION: Despite the high prevalence and increasing incidence, comprehensive and evidence based treatment approaches for OA in a primary care setting are neither established nor evaluated in Germany. If the evaluation of the presented approach reveals a clear benefit it is planned to provide this GP-centred interventions on a much larger scale
Health service utilization patterns of primary care patients with osteoarthritis
Contains fulltext :
53455.pdf ( ) (Open Access)BACKGROUND: To assess factors associated with visits to GPs, orthopaedists, and non-physician practitioners of complementary medicine (alternative practitioners) by primary care patients with osteoarthritis (OA). METHODS: Cross-sectional survey among 1250 consecutively addressed patients from 75 primary care practices in Germany. All patients suffered from OA of the knee or hip according to ACR criteria. They received questionnaires collecting sociodemographic data, data about health service utilisation, prescriptions, comorbidities. They also included established instruments as the Arthritis Impact Measurement Scale (AIMS2-SF) to assess disease-specific quality of life and the Patient Health Questionnaire (PHQ-9) to assess depression. Hierarchical stepwise multiple linear regression models were used to reveal significant factors influencing health service utilization. RESULTS: 1021 of 1250 (81.6%) questionnaires were returned. Nonrespondents did not differ from participants. Factors associated with health service use (HSU) varied between providers of care. Not being in a partnership, achieving a high score on the PHQ-9, increased pain severity reflected in the "symptom" scale of the AIMS2-SF, and an increased number of drug prescriptions predicted a high frequency of GP visits. The PHQ-9 score was also a predictor for visits to orthopaedists, as were previous GP contacts, a high score in the "symptom" scale as well as a high score in the "lower limb scale" of the AIMS2-SF. Regarding visits to alternative practitioners, a high score in the AIMS -"social" scale was a positive predictor as older people were less likely to visit them. CONCLUSION: Our results emphasize the need for awareness of psychological factors contributing to the use of health care providers. Addressing the revealed factors associated with HSU appropriately may lead to decreased health care utilization. But further research is needed to assess how this can be done successfully
Osteoarthritis and functional disability: results of a cross sectional study among primary care patients in Germany
Contains fulltext :
52359.pdf ( ) (Open Access)BACKGROUND: The aim of the study was to determine factors associated with functional disability in patients with OA. METHODS: 1250 questionnaires were distributed to OA outpatients from 75 general practices; 1021 (81.6%) were returned. Questionnaires included sociodemographic data, the short form of the Arthritis Impact Measurement Scale (AIMS2-SF), and the Patient Health Questionnaire (PHQ-9) to assess concomitant depression. A hierarchical stepwise multiple regression analysis with the AIMS2-SF dimension "lower body" as dependent was performed. RESULTS: Main factors associated with functional disability were depression symptoms, as reflected in a high score of the PHQ-9 (beta = 0.446; p < 0.0009), pain as reflected in the AIMS2-SF symptom scale (beta = 0.412; p = 0.001), and few social contacts (beta = 0.201; p < 0.042). A high body mass index was associated with lower functional ability (beta = 0.332; p = 0.005) whereas a higher educational level (beta = -0.279; p = 0.029) predicted less impairment. Increased age was a weak predictor (beta = 0.178; p = 0.001) of disability. With a p of 0.062 the radiological severity according to the grading of Kellgren and Lawrence slightly surpassed the required significance level for remaining in the final regression model. CONCLUSION: The results emphasize that psychological as well as physical factors need to be addressed similarly to improve functional ability of patients suffering from OA. More research with multifaceted and tailored interventions is needed to determine how these factors can be targeted appropriately
- …