13,569 research outputs found

    The Unusual Variability of the Large Magellanic Cloud Planetary Nebula RPJ 053059-683542

    Full text link
    We present images and light curves of the bipolar Planetary Nebula RPJ 053059-683542 that was discovered in the Reid-Parker AAO/UKST H-alpha survey of the Large Magellanic Cloud (LMC). The emission from this object appears entirely nebular, with the central star apparently obscured by a central band of absorption that bisects the nebula. The light curves, which were derived from images from the SuperMACHO project at CTIO, showed significant, spatially resolved variability over the period 2002 January through 2005 December. Remarkably, the emission from the two bright lobes of the nebula vary either independently, or similarly but with a phase lag of at least one year. The optical spectra show a low level of nebular excitation, and only modest N enrichment. Infrared photometry from the 2MASS and SAGE surveys indicates the presence of a significant quantity of dust. The available data imply that the central star has a close binary companion, and that the system has undergone some kind of outburst event that caused the nebular emission to first brighten and then fade. Further monitoring, high-resolution imaging, and detailed IR polarimetry and spectroscopy would uncover the nature of this nebula and the unseen ionizing source.Comment: Accepted for ApJ Letters; 6 page

    Heat stress incident prevalence and tennis matchplay performance at the Australian Open

    Full text link
    © 2017 Sports Medicine Australia Objectives: To examine the association of wet bulb globe temperature (WBGT) with the occurrence of heat-related incidents and changes in behavioural and matchplay characteristics in men's Grand Slam tennis. Design: On-court calls for trainers, doctors, cooling devices and water, post-match medical consults and matchplay characteristic data were collected from 360 Australian Open matches (first 4 rounds 2014–2016). Methods: Data were referenced against estimated WBGT and categorised into standard zones. Generalised linear models assessed the association of WBGT zone on heat-related medical incidences and matchplay variables. Results: On-court calls for doctor (47% increase per zone, p = 0.001), heat-related events (41%, p = 0.019), cooling devices (53%, p 32 °C and >28 °C, significant increases in heat-related calls (p = 0.019) and calls for cooling devices (p 32 °C) and cooling device callouts (>28 °C). However, few matchplay characteristics were noticeably affected, with only reduced net approaches and increased aces evident in higher estimated WBGT environments

    Bone mineral density, rib pain and other features of the female athlete triad in elite lightweight rowers

    Get PDF
    Objective: To determine bone mineral density (BMD) and the associations among BMD, menstrual history, disordered eating (DE), training history, intentional weight loss (IWL) and rib pain for the first time in female lightweight rowers. Setting: 9 lightweight rowing clubs, UK. Participants: 29 Caucasian female lightweight rowers volunteered. 21 (12 active, 9 retired) completed the study. Inclusion criteria: female lightweight rowers aged over 18 years. Exclusion criteria: participants with a history of bone disease, used medications known to influence BMD or if they were pregnant, lactating or postmenopausal. Main outcome measures: Dual-energy X-ray absorptiometry measured total body (TB) composition and BMD at the spine, femoral neck (FN), radius and TB. DE, oligomenorrhoea/amenorrhoea years; rib pain and training history. Results: DE was reported in six of the rowers. The active with DE started rowing younger (p<0.05) than those without, and their amount of IWL was associated with Eating Attitudes Test-26 score (p<0.05). Some participants reported a history of oligomenorrhoea/amenorrhoea 17 (76%) and/or rib pain 7 (32%) with those with rib pain having lower spine and TB Z-scores (p<0.05) than those without. Those with oligomenorrhoea/amenorrhoea had lower spine Z-scores (p<0.01) than those without. Twelve participants had low BMD; three at spine; one at FN; and eight at radius. Thirteen per cent of mean total training hours (18.6±9.1 h/week) were spent strength training (2.4±2.2 h/week). Conclusions: Upper body exercises incorporating multidimensional high peak bone strain were not reported and may need to be considered in their strength training to improve radial BMD. Results suggest IWL and high level training at a young age increases the likelihood of DE and there may be a lack of quality nutritional support for these athletes. Thus, multidisciplinary sport science support should be offered at a young age and perhaps also to consider changing the weight rules to prevent the development of the Triad

    Antimicrobial use and resistance and the relationship with health and biosecurity status in CIPARS data from Canadian grower-finisher swine herds

    Get PDF
    Antimicrobial resistance (AMR) is a global threat to public and animal health. The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS), created in 2002, is a national program dedicated to the collection, integration, analysis, and communication of trends in antimicrobial use (AMU) and resistance (AMR) in selected bacteria from humans, animals, and animal-derived food sources across Canada. This information supports (i) the creation of evidence‐based policies for AMU in hospitals, communities, and food‐animal production with the aim of prolonging the effectiveness of these drugs and (ii) the identification of appropriate measures to contain the emergence and spread of resistant bacteria among animals, food, and people

    Time evolution and squeezing of the field amplitude in cavity QED

    Full text link
    We present the conditional time evolution of the electromagnetic field produced by a cavity QED system in the strongly coupled regime. We obtain the conditional evolution through a wave-particle correlation function that measures the time evolution of the field after the detection of a photon. A connection exists between this correlation function and the spectrum of squeezing which permits the study of squeezed states in the time domain. We calculate the spectrum of squeezing from the master equation for the reduced density matrix using both the quantum regression theorem and quantum trajectories. Our calculations not only show that spontaneous emission degrades the squeezing signal, but they also point to the dynamical processes that cause this degradation.Comment: 12 pages. Submitted to JOSA

    Pseudomorphic Growth of a Single Element Quasiperiodic Ultrathin Film on a Quasicrystal Substrate

    Get PDF
    An ultrathin film with a periodic interlayer spacing was grown by the deposition of Cu atoms on thefivefold surface of the icosahedral Al70 Pd21 Mn9 quasicrystal. For coverages from 5 to 25 monolayers, a distinctive quasiperiodic low-energy electron diffraction pattern is observed. Scanning tunneling microscopy images show that the in-plane structure comprises rows having separations of S = 4.5 �0.2 �A and L = 7.3 0.3 A, whose ratio equals � =1.618... within experimental error. The sequences of such row separations form segments of terms of the Fibonacci sequence, indicative of the formation of a pseudomorphic Cu film

    Photon pressure induced test mass deformation in gravitational-wave detectors

    Get PDF
    A widely used assumption within the gravitational-wave community has so far been that a test mass acts like a rigid body for frequencies in the detection band, i.e. for frequencies far below the first internal resonance. In this article we demonstrate that localized forces, applied for example by a photon pressure actuator, can result in a non-negligible elastic deformation of the test masses. For a photon pressure actuator setup used in the gravitational wave detector GEO600 we measured that this effect modifies the standard response function by 10% at 1 kHz and about 100% at 2.5 kHz

    Constraints from 26^{26}Al Measurements on the Galaxy's Recent Global Star Formation Rate and Core Collapse Supernovae Rate

    Get PDF
    Gamma-rays from the decay of 26^{26}Al offer a stringent constraint on the Galaxy's global star formation rate over the past million years, supplementing other methods for quantifying the recent Galactic star formation rate, such as equivalent widths of Hα\alpha emission. Advantages and disadvantages of using 26^{26}Al gamma-ray measurements as a tracer of the massive star formation rate are analyzed. Estimates of the Galactic 26^{26}Al mass derived from COMPTEL measurements are coupled with a simple, analytical model of the 26^{26}Al injection rate from massive stars and restrict the Galaxy's recent star formation rate to \hbox{5 ±\pm 4 M\sun yr1^{-1}}. In addition, we show that the derived 26^{26}Al mass implies a present day \hbox{Type II + Ib} supernovae rate of 3.4 ±\pm 2.8 per century, which seems consistent with other independent estimates of the Galactic core collapse supernova rate. If some independent measure of the massive star initial mass function or star formation rate or \hbox{Type II + Ib} supernovae rate were to become available (perhaps through estimates of the Galactic 60^{60}Fe mass), then a convenient way to restrain, or possibly determine, the other parameters is presented.Comment: 11 pages including 1 figure, ApJ in pres
    corecore