320 research outputs found
On Semiclassical Limits of String States
We explore the relation between classical and quantum states in both open and
closed (super)strings discussing the relevance of coherent states as a
semiclassical approximation. For the closed string sector a gauge-fixing of the
residual world-sheet rigid translation symmetry of the light-cone gauge is
needed for the construction to be possible. The circular target-space loop
example is worked out explicitly.Comment: 12 page
Home-based versus centre-based cardiac rehabilitation: Abridged Cochrane systematic review and meta-analysis
Objective: To update the Cochrane review comparing the effects of home-based and supervised centre-based cardiac rehabilitation (CR) on mortality and morbidity, quality of life, and modifiable cardiac risk factors in patients with heart disease.
Methods: Systematic review and meta-analysis. The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO and CINAHL were searched up to October 2014, without language restriction. Randomised trials comparing home-based and centre-based CR programmes in adults with myocardial infarction, angina, heart failure or who had undergone coronary revascularisation were included.
Results: 17 studies with 2172 patients were included. No difference was seen between home-based and centre-based CR in terms of: mortality (relative risk (RR) 0.79, 95% CI 0.43 to 1.47); cardiac events; exercise capacity (mean difference (MD) −0.10, −0.29 to 0.08); total cholesterol (MD 0.07 mmol/L, −0.24 to 0.11); low-density lipoprotein cholesterol (MD −0.06 mmol/L, −0.27 to 0.15); triglycerides (MD −0.16 mmol/L, −0.38 to 0.07); systolic blood pressure (MD 0.2 mm Hg, −3.4 to 3.8); smoking (RR 0.98, 0.79 to 1.21); health-related quality of life and healthcare costs. Lower high-density lipoprotein cholesterol (MD −0.07 mmol/L, −0.11 to −0.03, p=0.001) and lower diastolic blood pressure (MD −1.9 mm Hg, −0.8 to −3.0, p=0.009) were observed in centre-based participants. Home-based CR was associated with slightly higher adherence (RR 1.04, 95% CI 1.01 to 1.07).
Conclusions: Home-based and centre-based CR provide similar benefits in terms of clinical and health-related quality of life outcomes at equivalent cost for those with heart failure and following myocardial infarction and revascularisation
The Hidden Curriculum of Veterinary Education: Mediators and Moderators of Its Effects
The “hidden curriculum” has long been supposed to have an effect on students' learning during their clinical education, and in particular in shaping their ideas of what it means to be a professional. Despite this, there has been little evidence linking specific changes in professional attitudes to the individual components of the hidden curriculum. This study aimed to recognize those components that led to a change in students' professional attitudes at a UK veterinary school, as well as to identify the attitudes most affected. Observations were made of 11 student groups across five clinical rotations, followed by semi-structured interviews with 23 students at the end of their rotation experience. Data were combined and analyzed thematically, taking both an inductive and deductive approach. Views about the importance of technical competence and communication skills were promoted as a result of students' interaction with the hidden curriculum, and tensions were revealed in relation to their attitudes toward compassion and empathy, autonomy and responsibility, and lifestyle ethic. The assessment processes of rotations and the clinical service organization served to communicate the messages of the hidden curriculum, bringing about changes in student professional attitudes, while student-selected role models and the student rotation groups moderated the effects of these influences
Carbon myopia: the urgent need for integrated social, economic and environmental action in the livestock sector
Livestock have long been integral to food production systems, often not by choice but by need. While our knowledge of livestock greenhouse gas emissions (GHG) mitigation has evolved, the prevailing focus has been - somewhat myopically on technology applications associated with mitigation.Here, we (1) examine the global distribution of livestock GHG emissions, (2) explore social, economic and environmental co-benefits and trade-offs associated with mitigation interventions, and (3) critique approaches for quantifying GHG emissions.This review uncovered many insights. First, while GHG emissions from ruminant livestock are greatest in low and middle-income countries (LMIC; globally, 66% of emissions are produced by Latin America and the Caribbean, East and southeast Asia, and south Asia), the majority of mitigation strategies are designed for developed countries. This serious concern is heightened by the fact that 80% of growth in global meat production over the next decade will occur in LMIC. Second, few studies concurrently assess social, economic and environmental aspects of mitigation. Of the 54 interventions reviewed, only 16 had triple-bottom line benefit with medium-high mitigation potential. Third, while efforts designed to stimulate adoption of strategies allowing both emissions reduction (ER) and carbon sequestration (CS) would achieve the greatest net emissions mitigation, CS measures have greater potential mitigation and co-benefits.The scientific community must shift attention away from the prevailing myopic lens on carbon, towards more holistic, systems-based, multi-metric approaches that carefully consider the raison d'être for livestock systems. Consequential life-cycle assessments and systems-aligned socio-economic planetary boundaries offer useful starting points that may uncover leverage points and cross-scale emergent properties. Derivation of harmonised, globally-reconciled sustainability metrics requires iterative dialogue between stakeholders at all levels. Greater emphasis on the simultaneous characterisation of multiple sustainability dimensions would help avoid situations where progress made in one area causes maladaptive outcomes in other areas
Parity and diabetes risk among hispanic women from Colombia: cross-sectional evidence
OBJECTIVE: The association between parity and type 2 diabetes has been studied in developed countries and in Singapore and Chinese women but not in Hispanics. Herein we evaluated the association between parity (number of live births) with diabetes in a group of Hispanic postmenopausal women from Colombia. RESEARCH DESIGN AND METHODS: Herein we evaluated the association between parity and diabetes in a population of 1,795 women from Colombia. Women were divided in birth categories (0 [referent], 1 or 2, 3–5, 6 or > births). Medical history of diabetes and anthropometric characteristics were recorded. Logistic regressions were performed in order to find the association between parity and diabetes in bivariable and multivariable models after controlling for age, body mass index (BMI), waist hip ratio (WHR) and diabetes family history, among other variables. RESULTS: In our study, there was an association between parity and diabetes after adjusting for age, BMI and diabetes family history in the multiparous women groups when compared to the women with no births (Referent group) [1–2 births vs. referent OR 5.2 (95 CI 1.2–22.9), 3–5 births vs. referent OR 5.5 (1.3–23.0) and ≥6 births vs. referent OR 7.5 (1.8–31.8), respectively]. The association was maintained in two of the groups in the multivariable analysis [OR 5.0 (1.1–22.9) and 5.3 (1.2–23.5)], for 1 or 2 births and 6 or > births versus 0 births, respectively. Positive diabetes family history and WHR were also associated with an increased risk of diabetes [OR 4.6 (3.0–7.0) and 4.1 (2.0–8.1), respectively]. CONCLUSIONS: In postmenopausal Hispanic women, multiparity, as well as a positive family history of diabetes and a high waist-hip ratio were associated with higher diabetes risk
Extrapulmonary tuberculosis, human immunodeficiency virus, and foreign birth in North Carolina, 1993 – 2006
<p>Abstract</p> <p>Background</p> <p>The proportion of extrapulmonary tuberculosis (EPTB) reported in the United States has been gradually increasing. HIV infection and foreign birth are increasingly associated with tuberculosis and understanding their effect on the clinical presentation of tuberculosis is important.</p> <p>Methods</p> <p>Case-control study of 6,124 persons with tuberculosis reported to the North Carolina Division of Public health from January 1, 1993 to December 31, 2006. Multivariate logistic regression was used to obtain adjusted odds ratios measuring the associations of foreign birth region and US born race/ethnicity, by HIV status, with EPTB.</p> <p>Results</p> <p>Among all patients with tuberculosis, 1,366 (22.3%) had EPTB, 563 (9.2%) were HIV co-infected, and 1,299 (21.2%) were foreign born. Among HIV negative patients, EPTB was associated with being foreign born (adjusted ORs 1.36 to 5.09, depending on region of birth) and with being US born, Black/African American (OR 1.84; 95% CI 1.42, 2.39). Among HIV infected patients, EPTB was associated with being US born, Black/African American (OR 2.60; 95% CI 1.83, 3.71) and with foreign birth in the Americas (OR 5.12; 95% CI 2.84, 9.23).</p> <p>Conclusion</p> <p>Foreign born tuberculosis cases were more likely to have EPTB than US born tuberculosis cases, even in the absence of HIV infection. Increasing proportions of foreign born and HIV-attributable tuberculosis cases in the United States will likely result in a sustained burden of EPTB. Further research is needed to explore why the occurrence and type of EPTB differs by region of birth and whether host genetic and/or bacterial variation can explain these differences in EPTB.</p
Historical trends in survival of hospitalized heart failure patients: 2000 versus 1995
BACKGROUND: Population-based secular trends in survival of patients with congestive heart failure (CHF) are central to public health research on the burden of the syndrome. METHODS: Patients 35–79 years old with a CHF discharge code in 1995 or 2000 were identified in 22 Minneapolis-St. Paul hospitals. A sample of the records was abstracted (50% of 1995 records; 38% of 2000 records). A total of 2,257 patients in 1995 and 1,825 patients in 2000 were determined to have had a CHF-related hospitalization. Each patient was followed for one year to ascertain vital status. RESULTS: The risk profile of the 2000 patient cohort was somewhat worse than that of the 1995 cohort in both sex groups, but the distributions of age and left ventricular ejection fraction were similar. Within one year of admission in 2000, 28% of male patients and 27% of female patients have died, compared to 36% and 27% of their counterparts in 1995, respectively. In various Cox regression models the average year effect (2000 vs. 1995) was around 0.75 for men and 0.95 to 1.00 for women. The use of angiotensin converting-enzyme inhibitors and beta-blockers was associated with substantially lower hazard of death during the subsequent year. CONCLUSION: Survival of men who were hospitalized for CHF has improved during the second half of the 1990s. The trend in women was very weak, compatible with little to no change. Documented benefits of angiotensin converting-enzyme inhibitors and beta-blockers were evident in these observational data in both men and women
Race/Ethnicity and gender differences in health intentions and behaviors regarding exercise and diet for adults with type 2 diabetes: A cross-sectional analysis
<p>Abstract</p> <p>Background</p> <p>Self-management is the cornerstone of diabetes control and prevention of complications; however, it is undetermined whether differences in intention to adopt healthy lifestyles and actual healthy behavior exist across race/ethnic groups. This study evaluated the differences across racial-ethnic groups in self-reported medical advice received and health intentions and behaviors among adults with type 2 diabetes mellitus.</p> <p>Methods</p> <p>A cross-sectional analysis of the 2007 SHIELD US survey ascertained self-reported health intentions and behaviors for regular exercise, diet, and weight management among Non-Hispanic Caucasian (n = 2526), Non-Hispanic African-American (n = 706), and Hispanic (n = 179) respondents with type 2 diabetes.</p> <p>Results</p> <p>A similar proportion of respondents from each race-gender group (43%-56%) reported receiving healthcare advice to increase their exercise (P = 0.32). Significantly more minorities reported an intention to follow the exercise recommendation compared with Non-Hispanic Caucasians (P = 0.03). More Non-Hispanic African-American (29%) and Hispanic (27%) men reported exercising regularly compared with other race-gender groups (P = 0.02). Significantly more Non-Hispanic Caucasian women (74%) and Hispanic women (79%) reported trying to lose weight compared with other groups (P < 0.0001).</p> <p>Conclusions</p> <p>Differences in health intentions and healthy behaviors were noted across race-gender groups. More Non-Hispanic African-American men reported an intention to follow advice on exercising and self-report of exercising regularly was also higher compared with other race-gender groups. More Hispanic men reported high physical activity levels than other groups. Despite an increased willingness to follow healthcare recommendations for diet, >50% of respondents were obese among all race-gender groups.</p
Cluster Lenses
Clusters of galaxies are the most recently assembled, massive, bound
structures in the Universe. As predicted by General Relativity, given their
masses, clusters strongly deform space-time in their vicinity. Clusters act as
some of the most powerful gravitational lenses in the Universe. Light rays
traversing through clusters from distant sources are hence deflected, and the
resulting images of these distant objects therefore appear distorted and
magnified. Lensing by clusters occurs in two regimes, each with unique
observational signatures. The strong lensing regime is characterized by effects
readily seen by eye, namely, the production of giant arcs, multiple-images, and
arclets. The weak lensing regime is characterized by small deformations in the
shapes of background galaxies only detectable statistically. Cluster lenses
have been exploited successfully to address several important current questions
in cosmology: (i) the study of the lens(es) - understanding cluster mass
distributions and issues pertaining to cluster formation and evolution, as well
as constraining the nature of dark matter; (ii) the study of the lensed objects
- probing the properties of the background lensed galaxy population - which is
statistically at higher redshifts and of lower intrinsic luminosity thus
enabling the probing of galaxy formation at the earliest times right up to the
Dark Ages; and (iii) the study of the geometry of the Universe - as the
strength of lensing depends on the ratios of angular diameter distances between
the lens, source and observer, lens deflections are sensitive to the value of
cosmological parameters and offer a powerful geometric tool to probe Dark
Energy. In this review, we present the basics of cluster lensing and provide a
current status report of the field.Comment: About 120 pages - Published in Open Access at:
http://www.springerlink.com/content/j183018170485723/ . arXiv admin note:
text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author
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