56 research outputs found

    The effective action of D6-branes in N=1 type IIA orientifolds

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    We use a Kaluza-Klein reduction to compute the low-energy effective action for the massless modes of a spacetime-filling D6-brane wrapped on a special Lagrangian 3-cycle of a type IIA Calabi-Yau orientifold. The modifications to the characteristic data of the N=1 bulk orientifold theory in the presence of a D6-brane are analysed by studying the underlying Type IIA supergravity coupled to the brane worldvolume in the democratic formulation and performing a detailed dualisation procedure. The N=1 chiral coordinates are found to be in agreement with expectations from mirror symmetry. We work out the Kahler potential for the chiral superfields as well as the gauge kinetic functions for the bulk and the brane gauge multiplets including the kinetic mixing between the two. The scalar potential resulting from the dualisation procedure can be formally interpreted in terms of a superpotential. Finally, the gauging of the Peccei-Quinn shift symmetries of the complex structure multiplets reproduces the D-term potential enforcing the calibration condition for special Lagrangian 3-cycles.Comment: 48 pages, v2: typos corrected, references adde

    Comparison of body mass index with waist circumference and skinfold-based percent body fat in firefighters: adiposity classification and associations with cardiovascular disease risk factors

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    PurposeThis study aims to examine whether body mass index (BMI) overestimates the prevalence of overweight or obese firefighters when compared to waist circumference (WC) and skinfold-based percent body fat (PBF) and to investigate differential relationships of the three adiposity measures with other biological cardiovascular disease (CVD) risk factors.MethodsThe adiposity of 355 (347 males and eight females) California firefighters was assessed using three different measures. Other CVD risk factors (high blood pressure, high lipid profiles, high glucose, and low VO2 max) of the firefighters were also clinically assessed.ResultsThe prevalence of total overweight and obesity was significantly (p < 0.01) higher by BMI (80.4 %) than by WC (48.7 %) and by PBF (55.6 %) in male firefighters. In particular, the prevalence of overweight firefighters was much higher (p < 0.01) by BMI (57.3 %) than by WC (24.5 %) and PBF (38.3 %). 60-64 % of male firefighters who were assessed as normal weight by WC and PBF were misclassified as overweight by BMI. When overweight by BMI was defined as 27.5-29.9 kg/m(2) (vs. the standard definition of 25.0-29.9 kg/m(2)), the agreement of the adiposity classification increased between BMI and other two adiposity measures. Obese firefighters had the highest CVD risk profiles across all three adiposity measures. Only when overweight by BMI was defined narrowly, overweight firefighters had substantially higher CVD risk profiles. Obesity and overweight were less prevalent in female and Asian male firefighters.ConclusionsBMI overestimated the prevalence of total overweight and obesity among male firefighters, compared to WC and skinfold-based PBF. Overweight by BMI needs to be more narrowly defined, or the prevalence of BMI-based overweight (27.5-29.9 kg/m(2)) should be reported additionally for prevention of CVD among male firefighters

    Uncoupling between beta-adrenoceptors and adenylate cyclase in dog ischemic myocardium.

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    We evaluated the effects of ischemic injury on the myocardial adenylate cyclase system, 5 h after ligation of the left anterior descending coronary in 5 anesthetized dogs. Crude cardiac membrane preparations were isolated from control and ischemic areas of ventricular myocardium and tested for: 1. L-(125I)iodocyanopindolol binding, in the absence and presence of +/- -isoprenaline and GTP, and 2. adenylate cyclase activity. The density of beta-adrenoceptors increased by 35% in membranes from ischemic areas while the proportion of receptors in a high affinity state for +/- -isoprenaline decreased from 43% to 20%. Adenylate cyclase activities in the basal state and under stimulation with NaF, forskolin, Gpp(NH)p, +/- -isoprenaline and VIP were all markedly and similarly reduced, being only about 30% of comparable activities in membranes from control areas. The +/- -isoprenaline subsensitivity of cardiac adenylate cyclase can, thus, be attributed to a defective enzymatic system and not to a reduction in the number of beta-adrenoceptors implying that the internal components of the system were more sensitive to acute ischemia than the outward oriented hormone receptors. It is tempting to ascribe this uncoupling to a functional depletion in the guanine nucleotide-binding regulatory protein Ns that might reflect a loss of high energy phosphate stores including GTP.In VitroJournal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Taxonomic status of the Australian dingo: The case for Canis dingo Meyer, 1793

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    Copyright © 2019 Magnolia Press. The taxonomic status and systematic nomenclature of the Australian dingo remain contentious, resulting in decades of inconsistent applications in the scientific literature and in policy. Prompted by a recent publication calling for dingoes to be considered taxonomically as domestic dogs (Jackson et al. 2017, Zootaxa 4317, 201-224), we review the issues of the taxonomy applied to canids, and summarise the main differences between dingoes and other canids. We conclude that (1) the Australian dingo is a geographically isolated (allopatric) species from all other Canis, and is genetically, phenotypically, ecologically, and behaviourally distinct; and (2) the dingo appears largely devoid of many of the signs of domestication, including surviving largely as a wild animal in Australia for millennia. The case of defining dingo taxonomy provides a quintessential example of the disagreements between species concepts (e.g., biological, phylogenetic, ecological, morphological). Applying the biological species concept sensu stricto to the dingo as suggested by Jackson et al. (2017) and consistently across the Canidae would lead to an aggregation of all Canis populations, implying for example that dogs and wolves are the same species. Such an aggregation would have substantial implications for taxonomic clarity, biological research, and wildlife conservation. Any changes to the current nomen of the dingo (currently Canis dingo Meyer, 1793), must therefore offer a strong, evidence-based argument in favour of it being recognised as a subspecies of Canis lupus Linnaeus, 1758, or as Canis familiaris Linnaeus, 1758, and a successful application to the International Commission for Zoological Nomenclature - neither of which can be adequately supported. Although there are many species concepts, the sum of the evidence presented in this paper affirms the classification of the dingo as a distinct taxon, namely Canis dingo

    The prediction of visceral fat by DXA in the elderly: a comparison with computed tomography and anthropometry

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    INTRODUCTION: Effective methods for assessing visceral fat are important to investigate the role of visceral fat for the increased health risks in obesity. Techniques for direct measurement of soft tissue composition such as CT or MRI are expensive, time-consuming or require a relatively high radiation dose. Simple anthropometric methods, such as waist-to-hip ratio, waist circumference or sagittal diameter are widely used. However, these methods cannot differentiate between visceral and subcutaneous fat and are less accurate. The aim of the present study is to investigate whether the dual-energy X-ray absorptiometry (DXA) method, possibly combined with anthropometry, offers a good alternative to CT for the prediction of visceral fat in the elderly. METHODS: Subjects were participants in the Health ABC-study, a cohort study of black and white men and women aged 70-79, investigating the effect of weight-related health conditions on disablement. Total body fat and trunk fat were measured by DXA using a Hologic QDR 1500. A 10 mm CT scan at the L4-L5 level was acquired to measure visceral fat and total abdominal fat. Weight, height, sagittal diameter and waist circumference were measured using standard methods. Fat in a manually defined DXA subregion (4 cm slice at the top of iliac crest) at the abdomen was calculated in a sub-group of participants (n=150; 50% male; 45.3% Afro-American/54.7% Caucasian, age 70-79 y). This subregion, the standard trunk region and total fat were used as indicators of visceral fat. RESULTS: Total abdominal fat by DXA (subregion) was strongly correlated with total abdominal fat by CT (r ranging from 0.87 in white men to 0.98 in black women). The DXA subregion underestimated total abdominal fat by 10% compared to the CT slice. The underestimation by DXA was seen especially in people with less abdominal fat. The association of visceral fat by CT with the DXA subregion (r=0.66, 0.78, 0.79 and 0.65 for white and black men and women, respectively) was comparable with the association of the CT measure with the sagittal diameter (r=0.74, 0.70, 0.84 and 0.68). Combining DXA measurements with anthropometry gave only limited improvement for the prediction of visceral fat by CT compared to univariate models (maximal increase of r(2) 4%). CONCLUSION: DXA is a good alternative to CT for predicting total abdominal fat in an elderly population. For the prediction of visceral fat the sagittal diameter, which has a practical advantage compared to DXA, is just as effective
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