Extraordinary states of highly localised pressure and temperature can be generated upon the collapse of impulsively driven cavities. Direct observation of this phenomenon in solids has proved ...challenging, but recent advances in high-speed synchrotron radiography now permit the study of highly transient, subsurface events in real time. We present a study on the shock-induced collapse of spherical cavities in a solid polymethyl methacrylate medium, driven to shock states between 0.49 and 16.60 GPa. Utilising multi-MHz phase contrast radiography, extended sequences of the collapse process have been captured, revealing new details of interface motion, material failure and jet instability formation. Results reveal a rich array of collapse characteristics dominated by strength effects at low shock pressures and leading to a hydrodynamic response at the highest loading conditions.
Betatron radiation from laser wakefield accelerators is an ultrashort pulsed source of hard, synchrotron-like x-ray radiation. It emanates from a centimetre scale plasma accelerator producing GeV ...level electron beams. In recent years betatron radiation has been developed as a unique source capable of producing high resolution x-ray images in compact geometries. However, until now, the short pulse nature of this radiation has not been exploited. This report details the first experiment to utilize betatron radiation to image a rapidly evolving phenomenon by using it to radiograph a laser driven shock wave in a silicon target. The spatial resolution of the image is comparable to what has been achieved in similar experiments at conventional synchrotron light sources. The intrinsic temporal resolution of betatron radiation is below 100 fs, indicating that significantly faster processes could be probed in future without compromising spatial resolution. Quantitative measurements of the shock velocity and material density were made from the radiographs recorded during shock compression and were consistent with the established shock response of silicon, as determined with traditional velocimetry approaches. This suggests that future compact betatron imaging beamlines could be useful in the imaging and diagnosis of high-energy-density physics experiments.
Results are presented from a set of experiments designed to investigate factors that may influence proxy-based reconstructions of large-scale temperature patterns in past centuries. The factors ...investigated include 1) the method used to assimilate proxy data into a climate reconstruction, 2) the proxy data network used, 3) the target season, and 4) the spatial domain of the reconstruction. Estimates of hemispheric-mean temperature are formed through spatial averaging of reconstructed temperature patterns that are based on either the local calibration of proxy and instrumental data or a more elaborate multivariate climate field reconstruction approach. The experiments compare results based on the global multiproxy dataset used by Mann and coworkers, with results obtained using the extratropical Northern Hemisphere (NH) maximum latewood tree-ring density set used by Briffa and coworkers. Mean temperature reconstructions are compared for the full NH (Tropics and extratropics, land and ocean) and extratropical continents only, with varying target seasons (cold-season half year, warm-season half year, and annual mean). The comparisons demonstrate dependence of reconstructions on seasonal, spatial, and methodological considerations, emphasizing the primary importance of the target region and seasonal window of the reconstruction. The comparisons support the generally robust nature of several previously published estimates of NH mean temperature changes in past centuries and suggest that further improvements in reconstructive skill are most likely to arise from an emphasis on the quality, rather than quantity, of available proxy data.
To limit tail biting incidence, most pig producers in Europe tail dock their piglets. This is despite EU Council Directive 2008/120/EC banning routine tail docking and allowing it only as a last ...resort. The paper aims to understand what it takes to fulfil the intentions of the Directive by examining economic results of four management and housing scenarios, and by discussing their consequences for animal welfare in the light of legal and ethical considerations. The four scenarios compared are: ‘Standard Docked’, a conventional housing scenario with tail docking meeting the recommendations for Danish production (0.7 m2/pig); ‘Standard Undocked’, which is the same as ‘Standard Docked’ but with no tail docking, ‘Efficient Undocked’ and ‘Enhanced Undocked’, which have increased solid floor area (0.9 and 1.0 m2/pig, respectively) provision of loose manipulable materials (100 and 200 g/straw per pig per day) and no tail docking. A decision tree model based on data from Danish and Finnish pig production suggests that Standard Docked provides the highest economic gross margin with the least tail biting. Given our assumptions, Enhanced Undocked is the least economic, although Efficient Undocked is better economically and both result in a lower incidence of tail biting than Standard Undocked but higher than Standard Docked. For a pig, being bitten is worse for welfare (repeated pain, risk of infections) than being docked, but to compare welfare consequences at a farm level means considering the number of affected pigs. Because of the high levels of biting in Standard Undocked, it has on average inferior welfare to Standard Docked, whereas the comparison of Standard Docked and Enhanced (or Efficient) Undocked is more difficult. In Enhanced (or Efficient) Undocked, more pigs than in Standard Docked suffer from being tail bitten, whereas all the pigs avoid the acute pain of docking endured by the pigs in Standard Docked. We illustrate and discuss this ethical balance using numbers derived from the above-mentioned data. We discuss our results in the light of the EU Directive and its adoption and enforcement by Member States. Widespread use of tail docking seems to be accepted, mainly because the alternative steps that producers are required to take before resorting to it are not specified in detail. By tail docking, producers are acting in their own best interests. We suggest that for the practice of tail docking to be terminated in a way that benefits animal welfare, changes in the way pigs are housed and managed may first be required.
Summary
Appaloosa horses are predisposed to equine recurrent uveitis (ERU), an immune‐mediated disease characterized by recurring inflammation of the uveal tract in the eye, which is the leading ...cause of blindness in horses. Nine genetic markers from the ECA1 region responsible for the spotted coat color of Appaloosa horses, and 13 microsatellites spanning the equine major histocompatibility complex (ELA) on ECA20, were evaluated for association with ERU in a group of 53 Appaloosa ERU cases and 43 healthy Appaloosa controls. Three markers were significantly associated (corrected P‐value <0.05): a SNP within intron 11 of the TRPM1 gene on ECA1, an ELA class I microsatellite located near the boundary of the ELA class III and class II regions and an ELA class II microsatellite located in intron 1 of the DRA gene. Association between these three genetic markers and the ERU phenotype was confirmed in a second population of 24 insidious ERU Appaloosa cases and 16 Appaloosa controls. The relative odds of being an ERU case for each allele of these three markers were estimated by fitting a logistic mixed model with each of the associated markers independently and with all three markers simultaneously. The risk model using these markers classified ~80% of ERU cases and 75% of controls in the second population as moderate or high risk, and low risk respectively. Future studies to refine the associations at ECA1 and ELA loci and identify functional variants could uncover alleles conferring susceptibility to ERU in Appaloosa horses.
ABSTRACT High-resolution X-ray spectrometers onboard suborbital sounding rockets can search for dark matter candidates that produce X-ray lines, such as decaying keV-scale sterile neutrinos. Even ...with exposure times and effective areas far smaller than XMM-Newton and Chandra observations, high-resolution, wide field of view observations with sounding rockets have competitive sensitivity to decaying sterile neutrinos. We analyze a subset of the 2011 observation by the X-ray Quantum Calorimeter instrument centered on Galactic coordinates with an effective exposure of 106 s, obtaining a limit on the sterile neutrino mixing angle of at 95% CL for a 7 keV neutrino. Better sensitivity at the level of at 95% CL for a 7 keV neutrino is achievable with future 300-s observations of the galactic center by the Micro-X instrument, providing a definitive test of the sterile neutrino interpretation of the reported 3.56 keV excess from galaxy clusters.
Defaulting from anti-tuberculosis treatment hinders tuberculosis (TB) control.
To identify potential defaulters.
We conducted a cohort study in newly diagnosed Indonesian TB patients. We administered ...a questionnaire, prospectively identified defaulters (discontinued treatment ≥ 2 weeks) and assessed risk factors using Cox's regression.
Of 249 patients, 39 (16%) defaulted, 61% in the first 2 months. Default was associated with liver disease (HR 3.40, 95%CI 1.02-11.78), chest pain (HR 2.25, 95%CI 1.06-4.77), night sweats (HR 1.98, 95%CI 1.03-3.79), characteristics of the head of the household (self-employed, HR 2.47, 95%CI 1.15-5.34; patient's mother, HR 7.72, 95%CI 1.66-35.88), household wealth (HR 4.24, 95%CI 1.12-16.09), walking to clinic (HR 4.53, 95%CI 1.39-14.71), being unaccompanied at diagnosis (HR 30.49, 95%CI 7.55-123.07) or when collecting medication (HR 3.34, 95%CI 1.24-8.98) and low level of satisfaction with the clinic (HR 3.85, 95%CI 1.17-12.62) or doctors (HR 2.45, 95%CI 1.18-5.10). Health insurance (HR 0.24, 95%CI 0.07-0.74) and paying for diagnosis (HR 0.14, 95%CI 0.04-0.48) were protective.
Defaulting is common and occurs early. Interventions that improve clinic services, strengthen patient support and increase insurance coverage may reduce default in Indonesia.
Young children living with infectious tuberculosis (TB) cases are at high risk of infection and disease, and screening is recommended. This is rarely conducted in resource-limited settings. ...Identifying children most at risk of infection may be useful for setting practical screening policies.
Child contacts of smear-positive adult TB patients were invited for Mycobacterium tuberculosis infection and disease screening by symptoms, tuberculin skin test (TST), QuantiFERON-TB Gold In-Tube assay (QFT-GIT) and chest X-ray. Risk factors for infection were collected using a questionnaire and were calculated separately for TST, for QFT-GIT and for both tests combined.
Of 304 screened children 145/302 (48%) were positive using TST, 152/299 (51%) by QFT-GIT and 180/304 (59%) were positive using either or both tests. Positivity for both tests was associated with index case infectivity (acid-fast bacilli AFB 3+ vs. AFB 1+: TST OR 2.93, 95%CI 1.59-5.39; QFT-GIT OR 2.28, 95%CI 1.06-4.90) and exposure (child contact's parent is the index case: TST OR 7.04, 95%CI 2.23-22.28; QFT-GIT OR 4.30, 95%CI 1.48-12.45).
M. tuberculosis infection according to either test was high, supporting screening and preventive treatment. Children of smear-positive TB cases who accompany their parents to the clinic should be prioritised for immediate screening.
PDF
