Symmetric Rotating Wave Approximation for the Generalized Single-Mode Spin-Boson System

The single-mode spin-boson model exhibits behavior not included in the rotating wave approximation (RWA) in the ultra and deep-strong coupling regimes, where counter-rotating contributions become important. We introduce a symmetric rotating wave approximation that treats rotating and counter-rotating terms equally, preserves the invariances of the Hamiltonian with respect to its parameters, and reproduces several qualitative features of the spin-boson spectrum not present in the original rotating wave approximation both off-resonance and at deep strong coupling. The symmetric rotating wave approximation allows for the treatment of certain ultra and deep-strong coupling regimes with similar accuracy and mathematical simplicity as does the RWA in the weak coupling regime. Additionally, we symmetrize the generalized form of the rotating wave approximation to obtain the same qualitative correspondence with the addition of improved quantitative agreement with the exact numerical results. The method is readily extended to higher accuracy if needed. Finally, we introduce the two-photon parity operator for the two-photon Rabi Hamiltonian and obtain its generalized symmetric rotating wave approximation. The existence of this operator reveals a parity symmetry similar to that in the Rabi Hamiltonian as well as another symmetry that is unique to the two-photon case, providing insight into the mathematical structure of the two-photon spectrum, significantly simplifying the numerics, and revealing some interesting dynamical properties.Comment: 11 pages, 5 figure

The Southern African Regional Science Initiative (SAFARI 2000) : wet season campaigns

The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia (Kataba Forest) and Botswana (Pandamatenga, Maun, Okwa River Crossing, Tshane) during February 2000 and concentrated primarily on characterizing the land surface with respect to exchanges of matter and energy with the atmosphere. The second, conducted in February 2001, focused on fluxes of water, gases and energy between the canopy and the atmosphere at Maun, Botswana, and at Skukuza in the Kruger National Park, South Africa. Eddy covariance measurements at Skukuza and Maun were designed to collect a near-continuous record of the seasonality and inter-annual variability in savanna carbon, water and energy exchanges in representative savanna ecosystems. This paper gives brief descriptions of the sites, the measurements made, and the methods used. It highlights some preliminary results, particularly from the first campaign, and outlines the next stages of the SAFARI 2000 projec

High level of co-occurrence of risk factors for non-communicable diseases among Gambian adults: A national population-based health examination survey

Non-communicable diseases (NCDs) are the leading causes of morbidity and mortality globally. Co-occurrence of risk factors predisposes an individual to NCDs; the burden increases cumulatively with the number of risk factors. Our study aimed to examine the co-occurrence of NCD risk factors among adults in The Gambia. This study is based on a random nationally representative sample of 4111 adults aged 25-64 years (78% response rate) with data collected between January and March 2010 in The Gambia using the WHO STEPwise survey methods. We restricted our analysis to non-pregnant participants with valid information on five NCD risk factors: high blood pressure, smoking, obesity, low fruit and vegetable consumption, and physical inactivity (n = 3000 adults with complete data on all risk factors). We conducted age-adjusted and fully-adjusted gender stratified multinomial logistic regression analysis to identify factors associated with the number of NCD risk factors. More than 90% of adults had at least one risk factor. Only 7% (95% CI: 5.2-9.8) had no risk factor; 22% (95% CI: 19.1-24.9) had at least three. Older age and ethnicity were significantly associated with having three or more risk factors (versus none) among men in the fully adjusted model. Lower education, older age, and urban residence were significantly associated with three or more risk factors (versus none) among women. The burden of NCDs is expected to increase in The Gambia if preventive and control measures are not taken. There should be an integrated approach targeting all risk factors, including wider treatment and control of hypertension

The silent epidemic of obesity in The Gambia: evidence from a nationwide, population-based, cross-sectional health examination survey

OBJECTIVES: Non-communicable diseases account for 70% of global deaths; 80% occur in low-income and middle-income countries. The rapid increase of obesity in sub-Saharan Africa is a concern. We assessed generalised and abdominal obesity and their associated risk factors among adults in The Gambia. DESIGN: Nationwide cross-sectional health examination survey using the WHO STEPwise survey methods. SETTING: The Gambia. PARTICIPANTS: This study uses secondary analysis of a 2010 nationally representative random sample of adults aged 25-64 years (78% response rate). The target sample size was 5280, and 4111 responded. Analysis was restricted to non-pregnant participants with valid weight and height measurements (n=3533). PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome variable was generalised obesity, using WHO body mass index (BMI) thresholds. Analyses used non-response weighting and adjusted for the complex survey design. We conducted multinomial logistic regression analysis to identify factors associated with BMI categories. The secondary outcome variable was abdominal obesity, defined as high waist circumference (using the International Diabetes Federation thresholds for Europeans). RESULTS: Two-fifths of adults were overweight/obese, with a higher obesity prevalence in women (17%, 95% CI 14.7 to 19.7; men 8%, 95% CI 6.0 to 11.0). 10% of men and 8% of women were underweight. Urban residence (adjusted relative risk ratio 5.8, 95% CI 2.4 to 14.5), higher education (2.3, 1.2 to 4.5), older age, ethnicity, and low fruit and vegetable intake (2.8, 1.1 to 6.8) were strongly associated with obesity among men. Urban residence (4.7, 2.7 to 8.2), higher education (2.6, 1.1 to 6.4), older age and ethnicity were associated with obesity in women. CONCLUSION: There is a high burden of overweight/obesity in The Gambia. While obesity rates in rural areas were lower than in urban areas, obesity prevalence was higher among rural residents in this study compared with previous findings. Preventive strategies should be directed at raising awareness, discouraging harmful beliefs on weight, and promoting healthy diets and physical activity

Grounding osteopathic research – Introducing grounded theory

Over the last four decades there has been a proliferation of qualitative research into healthcare practice, including manual therapy. Grounded theory is the most widely used qualitative research methodology, and has contributed to the knowledge base of a number of healthcare professions. This Masterclass provides an introduction to grounded theory and uses a recent doctoral study into osteopathic clinical decision-making as an example to illustrate the main processes and procedures when conducting and evaluating grounded theory research. This paper highlights how grounded theory research may be of help in developing a robust and rounded evidence-base in relation to osteopathic practice. Keywords: Grounded theory, Qualitative research, Methodology, Research methods, Qualitative data analysis, Decision-making, Clinical reasoning, Osteopathy, Osteopathic medicin

Ab-Initio Calculation of Molecular Aggregation Effects: a Coumarin-343 Case Study

We present time-dependent density functional theory (TDDFT) calculations for single and dimerized Coumarin-343 molecules in order to investigate the quantum mechanical effects of chromophore aggregation in extended systems designed to function as a new generation of sensors and light-harvesting devices. Using the single-chromophore results, we describe the construction of effective Hamiltonians to predict the excitonic properties of aggregate systems. We compare the electronic coupling properties predicted by such effective Hamiltonians to those obtained from TDDFT calculations of dimers, and to the coupling predicted by the transition density cube (TDC) method. We determine the accuracy of the dipole-dipole approximation and TDC with respect to the separation distance and orientation of the dimers. In particular, we investigate the effects of including Coulomb coupling terms ignored in the typical tight-binding effective Hamiltonian. We also examine effects of orbital relaxation which cannot be captured by either of these models

Genetic variation and host-parasite specificity of Striga resistance and tolerance in rice: the need for predictive breeding

The parasitic weeds Striga asiatica and Striga hermonthica cause devastating yield losses to upland rice in Africa. Little is known about genetic variation in host resistance and tolerance across rice genotypes, in relation to virulence differences across Striga species and ecotypes. Diverse rice genotypes were phenotyped for the above traits in S. asiatica- (Tanzania) and S. hermonthica-infested fields (Kenya and Uganda) and under controlled conditions. New rice genotypes with either ecotype-specific or broad-spectrum resistance were identified. Resistance identified in the field was confirmed under controlled conditions, providing evidence that resistance was largely genetically determined. Striga-resistant genotypes contributed to yield security under Striga-infested conditions, although grain yield was also determined by the genotype-specific yield potential and tolerance. Tolerance, the physiological mechanism mitigating Striga effects on host growth and physiology, was unrelated to resistance, implying that any combination of high, medium or low levels of these traits can be found across rice genotypes. Striga virulence varies across species and ecotypes. The extent of Striga-induced host damage results from the interaction between parasite virulence and genetically determined levels of host-plant resistance and tolerance. These novel findings support the need for predictive breeding strategies based on knowledge of host resistance and parasite virulence

Burden of hypertension in The Gambia: evidence from a national World Health Organization (WHO) STEP survey

Background: Non-communicable diseases are increasing in sub-Saharan Africa and are estimated to account for 32% of adult deaths in The Gambia. Worldwide, prevalence of hypertension is highest in the African region (46%) and a very high proportion is undiagnosed. This study examined diagnosed and undiagnosed hypertension in The Gambian adult population. Methods: Data were collected in 2010 from a nationally representative random sample of 4111 adults aged 25-64 years, using the World Health Organization STEPwise cross-sectional survey methods. Analyses were restricted to non-pregnant participants with three valid blood pressure measurements (n = 3573). We conducted gender-stratified univariate and multivariate regression analyses to identify the strongest sociodemographic, behavioural and biological risk factors associated with hypertension. Results: Almost one-third of adults were hypertensive; a high proportion were undiagnosed, particularly among men (86% of men vs 71% of women with hypertension, P < 0.001). Rural and semi-urban residents and overweight/obese persons had increased odds of hypertension. Compared with urban residents, participants from one of the most rural regions had higher odds of hypertension among both men [adjusted odds ratio (AOR) 3.2; 95% CI: 1.6-6.4] and women (AOR 2.5; 95% CI: 1.3-4.6). Other factors strongly associated with hypertension in multivariate analyses were age, smoking, physical inactivity and ethnicity. Conclusions: Rural and semi-urban residence were strongly associated with hypertension, contrary to what has been found in similar studies in sub-Saharan Africa. Intervention to reduce the burden of hypertension in The Gambia could be further targeted towards rural areas

Decreasing trends in number of depot medroxyprogesterone acetate starters in Norway - a cross-sectional study

This is the peer reviewed version of the following article: Roksvaag, I. & Skjeldestad, F.E. (2018). Decreasing trends in number of depot medroxyprogesterone acetate starters in Norway - a cross-sectional study. Acta Obstetricia et Gynecologica Scandinavica, 97(2), 151-157, which has been published in final form at https://doi.org/10.1111/aogs.13262. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Introduction - In this study, we examined changes in depot medroxyprogesterone acetate (DMPA) prescriptions over a time‐period when new professions started prescribing, and when the method gained some negative media attention. Material and methods - The Norwegian Prescription Database provided data on hormonal contraception from 2006 through 2012. We estimated the annual number of DMPA users by calculating doses sold per day/1000 women and calculated, for each contraceptive method on annual basis, a proportion of defined daily doses of all hormonal contraceptives in five‐year age groups at reproductive age. All analyses were done in SPSS, version 22, with Chi‐square test, t‐test, and survival analysis with p Results - There were minor differences in overall DMPA use during the study years. The take‐out rate was equivalent to 11–12/1000 women aged 15–49 years. DMPA sales amounted to nearly 4% of all daily doses of hormonal contraceptives sold. General practitioners and physicians without a specialty were the major prescribers. The number of starters decreased by nearly 40% during the study years and was consistent across age groups. The average use duration among starters was 17.7 (95% CI 17.5–17.9) months (range 0–90). There were minor changes in the relative proportion of long‐term users beyond 24 months during the study years. Conclusions - DMPA plays a minor role in the overall use of hormonal contraception in Norway, even among teenagers. The number of starters is decreasing, indicating a more restrictive attitude toward first use, especially among general practitioners