7,366 research outputs found

    A qualitative exploration of whether lesbian and bisexual women are 'protected' from sociocultural pressure to be thin

    Get PDF
    Heterosexual women in Western cultures are known to experience body image concerns, dieting and disordered eating as a result of intense social pressures to be thin. However, it is theorised that lesbian and bisexual women belong to a subculture that is ‘protective’ of such demands. Fifteen non-heterosexual women were interviewed about their experiences of social pressure. Thematic analysis of their accounts suggests that such theorising may be inaccurate, because these lesbian and bisexual women did not feel ‘protected’ from social pressures and experienced body dissatisfaction. While they might attempt to resist thin idealisation, resistance is not centred around their sexuality

    (1,0) superconformal theories in six dimensions and Killing spinor equations

    Full text link
    We solve the Killing spinor equations of 6-dimensional (1,0) superconformal theories in all cases. In particular, we derive the conditions on the fields imposed by the Killing spinor equations and demonstrate that these depend on the isotropy group of the Killing spinors. We focus on the models proposed by Samtleben et al in \cite{ssw} and find that there are solutions preserving 1,2, 4 and 8 supersymmetries. We also explore the solutions which preserve 4 supersymmetries and find that many models admit string and 3-brane solitons as expected from the M-brane intersection rules. The string solitons are smooth regulated by the moduli of instanton configurations.Comment: 26 page

    Benthic Carbon fixation and cycling in diffuse hydrothermal and background sediments in the Bransfield Strait, Antarctica

    Get PDF
    Sedimented hydrothermal vents are likely to be widespread compared to hard substrate hot vents. They host chemosynthetic microbial communities which fix inorganic carbon (C) at the seafloor, as well as a wide range of macroinfauna, including vent-obligate and background non-vent taxa. There are no previous direct observations of carbon cycling at a sedimented hydrothermal vent. We conducted 13C isotope tracing experiments at three sedimented sites in the Bransfield Strait, Antarctica, which showed different degrees of hydrothermalism. Two experimental treatments were applied, with 13C added as either algal detritus (photosynthetic C), or as bicarbonate (substrate for benthic C fixation). Algal 13C was taken up by both bacteria and metazoan macrofaunal, but its dominant fate was respiration, as observed at deeper and more food-limited sites elsewhere. Rates of 13C uptake and respiration suggested that the diffuse hydrothermal site was not the hot spot of benthic C cycling that we hypothesised it would be. Fixation of inorganic C into bacterial biomass was observed at all sites, and was measurable at two out of three sites. At all sites, newly fixed C was transferred to metazoan macrofauna. Fixation rates were relatively low compared with similar experiments elsewhere; thus, C fixed at the seafloor was a minor C source for the benthic ecosystem. However, as the greatest amount of benthic C fixation occurred at the “Off Vent” (non-hydrothermal) site (0.077±0.034 mg C m−2 fixed during 60 h), we suggest that benthic fixation of inorganic C is more widespread than previously thought, and warrants further study

    Genetic Algorithm with Optimal Recombination for the Asymmetric Travelling Salesman Problem

    Full text link
    We propose a new genetic algorithm with optimal recombination for the asymmetric instances of travelling salesman problem. The algorithm incorporates several new features that contribute to its effectiveness: (i) Optimal recombination problem is solved within crossover operator. (ii) A new mutation operator performs a random jump within 3-opt or 4-opt neighborhood. (iii) Greedy constructive heuristic of W.Zhang and 3-opt local search heuristic are used to generate the initial population. A computational experiment on TSPLIB instances shows that the proposed algorithm yields competitive results to other well-known memetic algorithms for asymmetric travelling salesman problem.Comment: Proc. of The 11th International Conference on Large-Scale Scientific Computations (LSSC-17), June 5 - 9, 2017, Sozopol, Bulgari

    Direct high-precision measurement of the magnetic moment of the proton

    Full text link
    The spin-magnetic moment of the proton ÎŒp\mu_p is a fundamental property of this particle. So far ÎŒp\mu_p has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in units of the nuclear magneton ÎŒp=2.792847350(9)ÎŒN\mu_p=2.792847350(9)\mu_N. This measurement outperforms previous Penning trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty year old indirect measurement, in which significant theoretical bound state corrections were required to obtain ÎŒp\mu_p, by a factor of 3. By application of this method to the antiproton magnetic moment ÎŒpˉ\mu_{\bar{p}} the fractional precision of the recently reported value can be improved by a factor of at least 1000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.Comment: published in Natur

    Hormonal contraceptive use and smoking as risk factors for high-grade cervical intraepithelial neoplasia in unvaccinated women aged 30–44 years: A case-control study in New South Wales, Australia

    Get PDF
    Background Human papillomavirus (HPV) vaccines protect against HPV types 16/18, but do not eliminate the need to detect pre-cancerous lesions. Australian women vaccinated as teenage girls are now entering their mid-thirties. Since other oncogenic HPV types have been shown to be more prevalent in women ≄30 years old, understanding high grade cervical lesions in older women is still important. Hormonal contraceptives (HC) and smoking are recognised cofactors for the development of pre-malignant lesions. Methods 886 cases with cervical intraepithelial neoplasia (CIN) 2/3 and 3636 controls with normal cytology were recruited from the Pap Test Register of NSW, Australia. All women were aged 30–44 years. Conditional logistic regression was used to quantify the relationship of HC and smoking to CIN 2/3 adjusted for various factors. Results Current-users of HC were at higher risk for CIN 2/3 than never-users [odds ratio (OR) = 1.50, 95%CI = 1.03–2.17] and risk increased with increasing duration of use [ORs:1.13 (0.73–1.75), 1.51 (1.00–2.72), 1.82 (1.22–2.72) for <10, 10–14, ≄15 years of use; p-trend = 0.04]. Ex-users had risks similar to never-users (OR 1.08, 95%CI = 0.75–1.57) regardless of duration of use. Current smoking was significantly associated with CIN 2/3 (OR = 1.43, 95%CI = 1.14–1.80) and risk increased with increasing number of cigarettes/day (p-trend = 0.02). Among ex-smokers, the risk of CIN 2/3 decreased with increasing time since quitting (p-trend = 0.04). Conclusions In this benchmark study, current, long term users of HC and current smokers of ≄5 cigarettes/day were each at increased risk of developing CIN 2/3. Findings support smoking cessation in relation to decreasing the risk of pre-cancerous lesions and reinforce the continuing need for cervical screening for cancer prevention in vaccinated and unvaccinated populations

    Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes

    Get PDF
    Background The cardiovascular effect of liraglutide, a glucagon-like peptide 1 analogue, when added to standard care in patients with type 2 diabetes, remains unknown. Methods In this double-blind trial, we randomly assigned patients with type 2 diabetes and high cardiovascular risk to receive liraglutide or placebo. The primary composite outcome in the time-to-event analysis was the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The primary hypothesis was that liraglutide would be noninferior to placebo with regard to the primary outcome, with a margin of 1.30 for the upper boundary of the 95% confidence interval of the hazard ratio. No adjustments for multiplicity were performed for the prespecified exploratory outcomes. Results A total of 9340 patients underwent randomization. The median follow-up was 3.8 years. The primary outcome occurred in significantly fewer patients in the liraglutide group (608 of 4668 patients [13.0%]) than in the placebo group (694 of 4672 [14.9%]) (hazard ratio, 0.87; 95% confidence interval [CI], 0.78 to 0.97; P<0.001 for noninferiority; P=0.01 for superiority). Fewer patients died from cardiovascular causes in the liraglutide group (219 patients [4.7%]) than in the placebo group (278 [6.0%]) (hazard ratio, 0.78; 95% CI, 0.66 to 0.93; P=0.007). The rate of death from any cause was lower in the liraglutide group (381 patients [8.2%]) than in the placebo group (447 [9.6%]) (hazard ratio, 0.85; 95% CI, 0.74 to 0.97; P=0.02). The rates of nonfatal myocardial infarction, nonfatal stroke, and hospitalization for heart failure were nonsignificantly lower in the liraglutide group than in the placebo group. The most common adverse events leading to the discontinuation of liraglutide were gastrointestinal events. The incidence of pancreatitis was nonsignificantly lower in the liraglutide group than in the placebo group. Conclusions In the time-to-event analysis, the rate of the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke among patients with type 2 diabetes mellitus was lower with liraglutide than with placebo. (Funded by Novo Nordisk and the National Institutes of Health; LEADER ClinicalTrials.gov number, NCT01179048 .)

    Experimental observation of nonlinear Thomson scattering

    Get PDF
    A century ago, J. J. Thomson showed that the scattering of low-intensity light by electrons was a linear process (i.e., the scattered light frequency was identical to that of the incident light) and that light's magnetic field played no role. Today, with the recent invention of ultra-high-peak-power lasers it is now possible to create a sufficient photon density to study Thomson scattering in the relativistic regime. With increasing light intensity, electrons quiver during the scattering process with increasing velocity, approaching the speed of light when the laser intensity approaches 10^18 W/cm^2. In this limit, the effect of light's magnetic field on electron motion should become comparable to that of its electric field, and the electron mass should increase because of the relativistic correction. Consequently, electrons in such high fields are predicted to quiver nonlinearly, moving in figure-eight patterns, rather than in straight lines, and thus to radiate photons at harmonics of the frequency of the incident laser light, with each harmonic having its own unique angular distribution. In this letter, we report the first ever direct experimental confirmation of these predictions, a topic that has previously been referred to as nonlinear Thomson scattering. Extension of these results to coherent relativistic harmonic generation may eventually lead to novel table-top x-ray sources.Comment: including 4 figure

    Optical mesoscopy, machine learning and computational microscopy enable high information content diagnostic imaging of blood films

    Get PDF
    Automated image-based assessment of blood films has tremendous potential to support clinical haematology within overstretched healthcare systems. To achieve this, efficient and reliable digital capture of the rich diagnostic information contained within a blood film is a critical first step. However, this is often challenging, and in many cases entirely unfeasible, with the microscopes typically used in haematology due to the fundamental trade-off between magnification and spatial resolution. To address this, we investigated three state-of-the-art approaches to microscopic imaging of blood films which leverage recent advances in optical and computational imaging and analysis to increase the information capture capacity of the optical microscope: optical mesoscopy, which uses a giant microscope objective (Mesolens) to enable high resolution imaging at low magnification; Fourier ptychographic microscopy, a computational imaging method which relies on oblique illumination with a series of LEDs to capture high resolution information; and deep neural networks which can be trained to increase the quality of low magnification, low resolution images. We compare and contrast the performance of these techniques for blood film imaging for the exemplar case of Giemsa-stained peripheral blood smears. Using computational image analysis and shape-based object classification we demonstrate their use for automated analysis of red blood cell morphology and visualization and detection of small blood borne parasites such as the malarial parasite Plasmodium falciparum. Our results demonstrate that these new methods greatly increase the information capturing capacity of the light microscope with transformative potential for haematology and more generally across digital pathology. This article is protected by copyright. All rights reserved
    • 

    corecore