Changes in waist circumference independent of weight: Implications for population level monitoring of obesity

Population monitoring of obesity is most commonly conducted using body mass index (BMI). We test the hypothesis that because of increases in waist circumference (WC) independent of increases in weight, BMI alone detects an increasingly smaller proportion of the population with obesity. Methods: Australian adults with measured height, weight, and WC were selected from three nationally representative cross-sectional surveys (1989, 1999–2000, 2011–12; n = 8313, 5903 & 3904). Participants were defined as having obesity using classifications for an obese BMI (≥ 30 kg·m− 2) and substantially-increased-risk WC (≥ 88 cm [women], ≥ 102 cm [men]). Age-standardised prevalence of obesity according to BMI and/or WC, and the proportion of these detected by BMI and by WC were compared across surveys. Findings: Between 1989 and 2011–12, weight and WC increased by 5.4 kg and 10.7 cm (women), and by 7.0 kg and 7.3 cm (men). For women and men, 63% and 38% of increases in WC were independent of increases in weight. Over this period, the prevalence of obesity according to BMI and/or WC increased by 25.3 percentage-points for women (18.9% to 44.3%) and 21.1 percentage-points for men (17.1% to 38.2%). The proportion of these detected by BMI decreased for women by 20 percentage-points (77% to 57%) with no change for men. The proportion of these detected by WC increased for women and men by 10 percentage-points (87% to 97%) and 6 percentage-points (85% to 91%) respectively. Conclusion: BMI alone is detecting a decreasing proportion of those considered obese by BMI and/or WC. Renewed discussion regarding how we monitor obesity at the population level is required

Stochastic Acceleration in the Western Hotspot of Pictor A

Chandra's high resolution observations of radio galaxies require a revisit of the relevant electron acceleration processes. Although the diffusive shock particle acceleration model may explain spectra of spatially unresolved sources, it encounters difficulties in explaining the structure and spectral properties of recently discovered Chandra X-ray features in several low-power radio sources. We argue that these observations strongly suggest stochastic electron acceleration by magnetized turbulence, and show that the simplest stochastic particle acceleration model with energy independent acceleration and escape timescales can overcome most of these difficulties. We use the bright core of the western hotspot of Pictor A as an example to demonstrate the model characteristics, which may be tested with high energy observations.Comment: 12 pages, 2 figures. Accepted by ApJ Letter

Systematic profiling of Caenorhabditis elegans locomotive behaviors reveals additional components in G-protein Gαq signaling

Genetic screens have been widely applied to uncover genetic mechanisms of movement disorders. However, most screens rely on human observations of qualitative differences. Here we demonstrate the application of an automatic imaging system to conduct a quantitative screen for genes regulating the locomotive behavior in Caenorhabditis elegans. Two hundred twenty-seven neuronal signaling genes with viable homozygous mutants were selected for this study. We tracked and recorded each animal for 4 min and analyzed over 4,400 animals of 239 genotypes to obtain a quantitative, 10-parameter behavioral profile for each genotype. We discovered 87 genes whose inactivation causes movement defects, including 50 genes that had never been associated with locomotive defects. Computational analysis of the high-content behavioral profiles predicted 370 genetic interactions among these genes. Network partition revealed several functional modules regulating locomotive behaviors, including sensory genes that detect environmental conditions, genes that function in multiple types of excitable cells, and genes in the signaling pathway of the G protein Gαq, a protein that is essential for animal life and behavior. We developed quantitative epistasis analysis methods to analyze the locomotive profiles and validated the prediction of the γ isoform of phospholipase C as a component in the Gαq pathway. These results provided a system-level understanding of how neuronal signaling genes coordinate locomotive behaviors. This study also demonstrated the power of quantitative approaches in genetic studies

Bacteria in sputum of stable severe asthma and increased airway wall thickness

<p>Abstract</p> <p>Background</p> <p>Patients with chronic asthma have thicker intrapulmonary airways measured on high resolution computed tomography (HRCT). We determined whether the presence of lower airway bacteria was associated with increased airway wall thickness.</p> <p>Methods</p> <p>In 56 patients with stable severe asthma, sputum specimens obtained either spontaneously or after induction with hypertonic saline were cultured for bacteria and thoracic HRCT scans obtained. Wall thickness (W_T) and area (W_A) expressed as a ratio of airway diameter (D) and total area, respectively, were measured at five levels.</p> <p>Results</p> <p>Positive bacterial cultures were obtained in 29 patients, with <it>H. influenzae, P. aeruginosa </it>and <it>S. aureus </it>being the commonest strains. Logistic regression analysis showed that this was associated with the duration of asthma and the exacerbations during the past year. In airways > 2 mm, there was no significant difference in W_A(67.5 ± 5.4 vs 66.4 ± 5.4) and W_T/D (21.6 ± 2.7 vs 21.3 ± 2.4) between the culture negative versus positive groups. Similarly, in airways (≤ 2 mm), there were no significant differences in these parameters. The ratio of √wall area to P_iwas negatively correlated with FEV₁% predicted (p < 0.05).</p> <p>Conclusions</p> <p>Bacterial colonization of the lower airways is common in patients with chronic severe asthma and is linked to the duration of asthma and having had exacerbations in the past year, but not with an increase in airway wall thickness.</p

Intensified partner notification and repeat testing can improve the effectiveness of screening in reducing Chlamydia trachomatis prevalence: a mathematical modelling study.

BACKGROUND The Australian Chlamydia Control Effectiveness Pilot (ACCEPt) was a cluster randomised controlled trial designed to assess the effectiveness of annual chlamydia testing through general practice in Australia. The trial showed that testing rates increased among sexually active men and women aged 16-29 years, but after 3 years the estimated chlamydia prevalence did not differ between intervention and control communities. We developed a mathematical model to estimate the potential longer-term impact of chlamydia testing on prevalence in the general population. METHODS We developed an individual-based model to simulate the transmission of Chlamydia trachomatis in a heterosexual population, calibrated to ACCEPt data. A proportion of the modelled population were tested for chlamydia and treated annually at coverage achieved in the control and intervention arms of ACCEPt. We estimated the reduction in chlamydia prevalence achieved by increasing retesting and by treating the partners of infected individuals up to 9 years after introduction of the intervention. RESULTS Increasing the testing coverage in the general Australian heterosexual population to the level achieved in the ACCEPt intervention arm resulted in reduction in the population-level prevalence of chlamydia from 4.6% to 2.7% in those aged 16-29 years old after 10 years (a relative reduction of 41%). The prevalence reduces to 2.2% if the proportion retested within 4 months of treatment is doubled from the rate achieved in the ACCEPt intervention arm (a relative reduction of 52%), and to 1.9% if the partner treatment rate is increased from 30%, as assumed in the base case, to 50% (a relative reduction of 59%). CONCLUSION A reduction in C. trachomatis prevalence could be achieved if the level of testing as observed in the ACCEPt intervention arm can be maintained at a population level. More substantial reductions can be achieved with intensified case management comprising retesting of those treated and treatment of partners of infected individuals

The WiggleZ Dark Energy Survey: Star-formation in UV-luminous galaxies from their luminosity functions

We present the ultraviolet (UV) luminosity function of galaxies from the GALEX Medium Imaging Survey with measured spectroscopic redshifts from the first data release of the WiggleZ Dark Energy Survey. This sample selects galaxies with high star formation rates: at 0.6 < z < 0.9 the median star formation rate is at the upper 95th percentile of optically-selected (r<22.5) galaxies and the sample contains about 50 per cent of all NUV < 22.8, 0.6 < z < 0.9 starburst galaxies within the volume sampled. The most luminous galaxies in our sample (-21.0>M_NUV>-22.5) evolve very rapidly with a number density declining as (1+z)^{5\pm 1} from redshift z = 0.9 to z = 0.6. These starburst galaxies (M_NUV<-21 is approximately a star formation rate of 30 \msuny) contribute about 1 per cent of cosmic star formation over the redshift range z=0.6 to z=0.9. The star formation rate density of these very luminous galaxies evolves rapidly, as (1+z)^{4\pm 1}. Such a rapid evolution implies the majority of star formation in these large galaxies must have occurred before z = 0.9. We measure the UV luminosity function in 0.05 redshift intervals spanning 0.1<z<0.9, and provide analytic fits to the results. At all redshifts greater than z=0.55 we find that the bright end of the luminosity function is not well described by a pure Schechter function due to an excess of very luminous (M_NUV<-22) galaxies. These luminosity functions can be used to create a radial selection function for the WiggleZ survey or test models of galaxy formation and evolution. Here we test the AGN feedback model in Scannapieco et al. (2005), and find that this AGN feedback model requires AGN feedback efficiency to vary with one or more of the following: stellar mass, star formation rate and redshift.Comment: 27 pages; 13 pages without appendices. 22 figures; 11 figures in the main tex

Performance of lateral flow device and galactomannan for the detection of Aspergillus species in bronchoalveolar fluid of patients at risk for invasive pulmonary aspergillosis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111755/1/myc12327.pd

On measuring the covariance matrix of the nonlinear power spectrum from simulations

We show how to estimate the covariance of the power spectrum of a statistically homogeneous and isotropic density field from a single periodic simulation, by applying a set of weightings to the density field, and by measuring the scatter in power spectra between different weightings. We recommend a specific set of 52 weightings containing only combinations of fundamental modes, constructed to yield a minimum variance estimate of the covariance of power. Numerical tests reveal that at nonlinear scales the variance of power estimated by the weightings method substantially exceeds that estimated from a simple ensemble method. We argue that the discrepancy is caused by beat-coupling, in which products of closely spaced Fourier modes couple by nonlinear gravitational growth to the beat mode between them. Beat-coupling appears whenever nonlinear power is measured from Fourier modes with a finite spread of wavevector, and is therefore present in the weightings method but not the ensemble method. Beat-coupling inevitably affects real galaxy surveys, whose Fourier modes have finite width. Surprisingly, the beat-coupling contribution dominates the covariance of power at nonlinear scales, so that, counter-intuitively, it is expected that the covariance of nonlinear power in galaxy surveys is dominated not by small scale structure, but rather by beat-coupling to the largest scales of the survey.Comment: 19 pages, 4 figures. To appear in Monthly Notices of the Royal Astronomical Society. Revised to match accepted versio

Autophagy impairment by African swine fever virus

African swine fever is a devastating disease of domestic swine and wild boar caused by a large double-stranded DNA virus that encodes for more than 150 open reading frames. There is no licensed vaccine for the disease and the most promising current candidates are modified live viruses that have been attenuated by deletion of virulence factors. Like many viruses African swine fever virus significantly alters the host cell machinery to benefit its replication and viral genes that modify host pathways represent promising targets for development of gene deleted vaccines. Autophagy is an important cellular pathway that is involved in cellular homeostasis, innate and adaptive immunity and therefore is manipulated by a number of different viruses. Autophagy is regulated by a complex protein cascade and here we show that African swine fever virus can block formation of autophagosomes, a critical functional step of the autophagy pathway through at least two different mechanisms. Interestingly this does not require the A179L gene that has been shown to interact with Beclin-1, an important autophagy regulator

The WiggleZ Dark Energy Survey: improved distance measurements to z = 1 with reconstruction of the baryonic acoustic feature

We present significant improvements in cosmic distance measurements from the WiggleZ Dark Energy Survey, achieved by applying the reconstruction of the baryonic acoustic feature technique. We show using both data and simulations that the reconstruction technique can often be effective despite patchiness of the survey, significant edge effects and shot-noise. We investigate three redshift bins in the redshift range 0.2 < z < 1, and in all three find improvement after reconstruction in the detection of the baryonic acoustic feature and its usage as a standard ruler. We measure model-independent distance measures DV(rsfid/rs) of 1716 ± 83, 2221 ± 101, 2516 ± 86 Mpc (68 per cent CL) at effective redshifts z = 0.44, 0.6, 0.73, respectively, where DV is the volume-averaged distance, and rs is the sound horizon at the end of the baryon drag epoch. These significantly improved 4.8, 4.5 and 3.4 per cent accuracy measurements are equivalent to those expected from surveys with up to 2.5 times the volume of WiggleZ without reconstruction applied. These measurements are fully consistent with cosmologies allowed by the analyses of the Planck Collaboration and the Sloan Digital Sky Survey. We provide the DV(rsfid/rs) posterior probability distributions and their covariances. When combining these measurements with temperature fluctuations measurements of Planck, the polarization of Wilkinson Microwave Anisotropy Probe 9, and the 6dF Galaxy Survey baryonic acoustic feature, we do not detect deviations from a flat Λ cold dark matter (ΛCDM) model. Assuming this model, we constrain the current expansion rate to H₀ = 67.15 ± 0.98 km s⁻¹Mpc⁻¹. Allowing the equation of state of dark energy to vary, we obtain wDE = −1.080 ± 0.135. When assuming a curved ΛCDM model we obtain a curvature value of ΩK = −0.0043 ± 0.0047