Spin(7) compactifications and 1/4-BPS vacua in heterotic supergravity.

We continue the investigation into non-maximally symmetric compactifications of the heterotic string. In particular, we consider compactifications where the internal space is allowed to depend on two or more external directions. For preservation of supersymmetry, this implies that the internal space must in general be that of a Spin(7) manifold, which leads to a 1/4-BPS four-dimensional supersymmetric perturbative vacuum breaking all but one supercharge. We find that these solutions allow for internal geometries previously excluded by the domain-wall-type solutions, and hence the resulting four-dimensional superpotential is more generic. In particular, we find an interesting resemblance to the superpotentials that appear in non-geometric flux compactifications of type II string theory. If the vacua are to be used for phenomenological applications, they must be lifted to maximal symmetry by some non-perturbative or higher-order effect.NCS201

A prospective study of asthma incidence and its predictors: the RHINE study.

To access publisher full text version of this article. Please click on the hyperlink in Additional LinkThe objective of this longitudinal study was to estimate the incidence rate of asthma, and to compare the incidence between subjects with or without baseline reporting of certain respiratory symptoms. A follow-up of the random population samples in the European Respiratory Health Survey (ECRHS) in Sweden, Norway, Denmark, Iceland and Estonia was conducted in 1999-2001, in a population aged 30-54 yrs at follow-up (n=14,731). Asthma was defined as reporting either asthma or physician-diagnosed asthma, and a reported year when asthma symptoms were first noticed. Incidence rates, incidence rate ratios and hazard ratios were calculated with 95% confidence intervals. The incidence rate of asthma was 2.2 cases per 1,000 person-yrs. The incidence was higher among females (2.9 cases.1,000 person-yrs(-1)) than among males (1.5 cases.1,000 person-yrs(-1)). When subjects with baseline reporting of wheezing were excluded, the incidence rate decreased to 1.7 cases.1,000 person-yrs(-1), with a further decrease to 1.5 cases.1,000 person-yrs(-1) after exclusion of subjects with wheezing, nocturnal dyspnoea, chest tightness and cough. There was a strong association between onset of asthma and wheezing at baseline. In this prospective, population-based study, the incidence rate of asthma in the whole population sample ranged 1.5-2.2.1,000 person-yrs(-1), with a higher incidence range among females. The incidence was dependent on the extent to which subjects with respiratory symptoms were excluded from follow-up. Hence, for comparability between studies, the exclusion criteria in the follow-up population must be stated

Socioeconomic Differences in Exposure to Tobacco Smoke Pollution (TSP) in Bangladeshi Households with Children: Findings from the International Tobacco Control (ITC) Bangladesh Survey

This study assessed the pattern of exposure to tobacco smoke pollution (TSP; also known as, secondhand smoke) in Bangladeshi households with children and examined the variations in household smoking restrictions and perception of risk for children’s exposure to TSP by socioeconomic status. We interviewed 1,947 respondents from Bangladeshi households with children from the first wave (2009) of the International Tobacco Control (ITC) Bangladesh Survey. 43.5% of the respondents had complete smoking restrictions at home and 39.7% were very or extremely concerned about TSP risk to children’s health. Participants with lower level of education were significantly less likely to be concerned about the risk of TSP exposure to children’s health and less likely to adopt complete smoking restrictions at home. Logistic regression revealed that the predictors of concern for TSP exposure risk were educational attainment of 1 to 8 years (OR = 1.94) or 9 years or more (OR = 4.07) and being a smoker (OR = 0.24). The predictors of having complete household smoking restrictions were: urban residence (OR = 1.64), attaining education of 9 years or more (OR = 1.94), being a smoker (OR = 0.40) and being concerned about TSP exposure risk to children (OR = 3.25). The findings show that a high proportion of adults with children at home smoke tobacco at home and their perceptions of risk about TSP exposure to children’s health were low. These behaviours were more prevalent among rural smokers who were illiterate. There is a need for targeted intervention, customized for low educated public, on TSP risk to children’s health and tobacco control policy with specific focus on smoke-free home

Describing the status of reproductive ageing simply and precisely: A reproductive ageing score based on three questions and validated with hormone levels

Equation 6. Quadratic logistic function approximating the function mu(B)(with age in years). Equation 1. Proportion of women who have regular menstruation for each number of reported menstruations in the last year(with period = number of periods per year, x = number of women answering "Yes" to the question: "Do you have regular periods?", y = number of women answering "No, they have been irregular for a few months" and z = number of women answering "No, my periods have stopped", e.g. x(11) = number of women reporting regular menstruation among those who report 11 menstruations in the last 12 months). Equation 5. Biquadratic exponential function mu(A)depending of the number of periods. Equation 3. Age modification by smoking and oophorectomy. Equation 2. Proportion of women whose menstruations have already stopped, for each reported year of age(with age = age in years, x = number of women answering "Yes" to the question: "Do you have regular periods?", y = number of women answering "No, they have been irregular for a few months", z = number of women answering "No, my periods have stopped", e.g. x(40) = number of women reporting regular menstruations among those who are 40 years old). Equation 7. Final formula to calculate the reproductive ageing score (RAS)(with period being the number of periods per year and age as the age in years, modified according to smoking status and oophorectomy). Objective Most women live to experience menopause and will spend 4-8 years transitioning from fertile age to full menstrual stop. Biologically, reproductive ageing is a continuous process, but by convention, it is defined categorically as pre-, peri- and postmenopause;categories that are sometimes supported by measurements of sex hormones in blood samples. We aimed to develop and validate a new tool, a reproductive ageing score (RAS), that could give a simple and yet precise description of the status of reproductive ageing, without hormone measurements, to be used by health professionals and researchers. Methods Questionnaire data on age, menstrual regularity and menstrual frequency was provided by the large multicentre population-based RHINE cohort. A continuous reproductive ageing score was developed from these variables, using techniques of fuzzy mathematics, to generate a decimal number ranging from 0.00 (nonmenopausal) to 1.00 (postmenopausal). The RAS was then validated with sex hormone measurements (follicle stimulating hormone and 17 beta-estradiol) and interview-data provided by the large population-based ECRHS cohort, using receiver-operating characteristics (ROC). Results The RAS, developed from questionnaire data of the RHINE cohort, defined with high precision and accuracy the menopausal status as confirmed by interview and hormone data in the ECRHS cohort. The area under the ROC curve was 0.91 (95% Confidence interval (CI): 0.90-0.93) to distinguish nonmenopausal women from peri- and postmenopausal women, and 0.85 (95% CI: 0.83-0.88) to distinguish postmenopausal women from nonmenopausal and perimenopausal women. Conclusions: The RAS provides a useful and valid tool for describing the status of reproductive ageing accurately, on a continuous scale from 0.00 to 1.00, based on simple questions and without requiring blood sampling. The score allows for a more precise differentiation than the conventional categorisation in pre-, peri- and postmenopause. This is useful for epidemiological research and clinical trials. Equation 4. The reproductive ageing score as an aggregation function of mu(A)and mu(B)

Randomized Clinical Trial of Laparoscopic Versus Open Repair of the Perforated Peptic Ulcer: The LAMA Trial

Background: Laparoscopic surgery has become popular during the last decade, mainly because it is associated with fewer postoperative complications than the conventional open appr

The environmental impact of fertilizer embodied in a wheat-to-bread supply chain

Food production and consumption cause approximately one-third of total greenhouse gas emissions, and therefore delivering food security challenges not only the capacity of our agricultural system, but also its environmental sustainability. Knowing where and at what level environmental impacts occur within particular food supply chains is necessary if farmers, agri-food industries and consumers are to share responsibility to mitigate these impacts. Here we present an analysis of a complete supply chain for a staple of the global diet, a loaf of bread. We obtained primary data for all the processes involved in the farming, production and transport systems that lead to the manufacture of a particular brand of 800 g loaf. The data were analysed using an advanced life cycle assessment (LCA) tool, yielding metrics of environmental impact, including greenhouse gas emissions. We show that more than half of the environmental impact of producing the loaf of bread arises directly from wheat cultivation, with the use of ammonium nitrate fertilizer alone accounting for around 40%. These findings reveal the dependency of bread production on the unsustainable use of fertilizer and illustrate the detail needed if the actors in the supply chain are to assume shared responsibility for achieving sustainable food production