We present the photometric calibration of the Swift Ultraviolet/Optical Telescope (UVOT) which includes: optimum photometric and background apertures, effective area curves, colour transformations, ...conversion factors for count rates to flux and the photometric zero-points (which are accurate to better than 4 per cent) for each of the seven UVOT broad-band filters. The calibration was performed with observations of standard stars and standard star fields that represent a wide range of spectral star types. The calibration results include the position-dependent uniformity, and instrument response over the 1600–8000 Å operational range. Because the UVOT is a photon-counting instrument, we also discuss the effect of coincidence loss on the calibration results. We provide practical guidelines for using the calibration in UVOT data analysis. The results presented here supersede previous calibration results.
Denosumab (Amgen, Thousand Oaks, California, USA) is a new bone antiresorptive agent used in patients with osteoporosis or metastatic cancer to the bones. As with the bisphosphonates that are used as ...antiresorptive medications, denosumab has been associated with osteonecrosis of the jaws (ONJ).
Over the past two years there has been an increase in the literature describing ONJ in patients receiving agents such as denosumab. Due to promising study results that demonstrate the effectiveness of denosumab in avoiding skeletal complications related to osteoporosis and metastatic bone disease, more patients will receive denosumab in the future. It is reported that this has the potential to become a comparable challenge to bisphosphonate related osteonecrosis of the jaws (BRONJ) for clinicians.
This article describes the management of two patients that developed ONJ while receiving denosumab, reviews the incidence of ONJ associated with denosumab, and contrasts the pharmacokinetics of denosumab and the bisphosphonates.
The importance of avoiding interventional dental treatment until denosumab has been withdrawn for six months cannot be overstated.
The Ultraviolet/Optical Telescope (UVOT) is one of three instruments onboard the Swift observatory. The photometric calibration has been published, and this paper follows up with details on other ...aspects of the calibration including a measurement of the point spread function with an assessment of the orbital variation and the effect on photometry. A correction for large-scale variations in sensitivity over the field of view is described, as well as a model of the coincidence loss which is used to assess the coincidence correction in extended regions. We have provided a correction for the detector distortion and measured the resulting internal astrometric accuracy of the UVOT, also giving the absolute accuracy with respect to the International Celestial Reference System. We have compiled statistics on the background count rates, and discuss the sources of the background, including instrumental scattered light. In each case, we describe any impact on UVOT measurements, whether any correction is applied in the standard pipeline data processing or whether further steps are recommended.
Cerebral white matter hyperintensities (WMH) persist in children and adults living with HIV, despite effective combination antiretroviral therapy (cART). As age and principal routes of transmission ...differ between children (perinatally) and adults (behaviorally), comparing the characteristics and determinants of WMH between these populations may increase our understanding of the pathophysiology of WMH. From separate cohorts of 31 children (NOVICE) and 74 adults (AGEhIV), we cross-sectionally assessed total WMH volume and number of WMH per location (periventricular vs. deep) using fluid-attenuated inversion recovery (FLAIR) MRI images. WMH were either periventricular when within 10mm of the lateral ventricles, or deep otherwise. We assessed patient- or HIV-related determinants of total WMH volume (adjusted for intracranial volume) and location of WMH using logistic regression, while stratifying on children and adults. At enrollment, median age of participants was 13.8 years (IQR 11.4-15.9) for children and 53.4 years (IQR 48.3-60.8) for adults and 27/31 children (87%) and 74/74 adults (100%) had an HIV RNA viral load <200 copies/mL. WMH were present in 16/27 (52%) children and 74/74 adults (100%). The prevalence of deep WMH was not different between groups, (16/16 100% in children vs. 71/74 96% in adults, p = 0,999), yet periventricular WMH were more prevalent in adults (74/74 100%) compared to children (9/16; 56%) (p<0.001). Median WMH volume was higher in adults compared to children (1182 mm3 425-2617 vs. 109 mm3 61.7-625, p<0.001). In children, boys were more likely to have deep WMH compared to girls. In adults, older age was associated with higher total WMH volume, and age, hypertension and lower CD4+ T-lymphocyte nadir with a higher number of periventricular WMH. Our findings suggest that the location of WMH differs between children and adults living with HIV, hinting at a different underlying pathogenesis.
Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of ...energetic electron enhancements in the outer radiation belts. Substorms inject a keV “seed” population into the inner magnetosphere which is subsequently energized through wave‐particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following substorms and quiet intervals. However, there are up to 3 times as many increases in TRBEC following substorm intervals. There is a lag of 1–3 days between the substorm or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following substorms and quiet intervals, the mean change in TRBEC following substorms or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM‐H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels.
Key Points
The radiation belts are inherently lossy
Substorms increase the likelihood of an increase in the radiation belts to 50%
The radiation belts have a memory of magnetospheric activity for up to 6 days
We present the first Swift Ultraviolet/Optical Telescope (UVOT) gamma-ray burst (GRB) afterglow catalog. The catalog contains data from over 64,000 independent UVOT image observations of 229 GRBs ...first detected by Swift, the High Energy Transient Explorer 2 (HETE2), the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Interplanetary Network (IPN). The catalog covers GRBs occurring during the period from 2005 January 17 to 2007 June 16 and includes ~86% of the bursts detected by the Swift Burst Alert Telescope (BAT). The catalog provides detailed burst positional, temporal, and photometric information extracted from each of the UVOT images. Positions for bursts detected at the 3 sigma level are provided with a nominal accuracy, relative to the USNO-B1 catalog, of ~025. Photometry for each burst is given in three UV bands, three optical bands, and a 'white' or open filter. Upper limits for magnitudes are reported for sources detected below 3 sigma . General properties of the burst sample and light curves, including the filter-dependent temporal slopes, are also provided. The majority of the UVOT light curves, for bursts detected at the 3 sigma level, can be fit by a single power-law, with a median temporal slope ( alpha ) of 0.96, beginning several hundred seconds after the burst trigger and ending at ~1 X 105 s. The median UVOT v-band (~5500 A) magnitude at 2000 s for a sample of 'well'-detected bursts is 18.02. The UVOT flux interpolated to 2000 s after the burst, shows relatively strong correlations with both the prompt Swift BAT fluence, and the Swift X-ray flux at 11 hr after the trigger.
A new 1.4 GHz, 19-element, dual-polarization, cryogenic phased-array feed (PAF) radio astronomy receiver has been developed for the Robert C. Byrd Green Bank Telescope (GBT) as part of the Focal ...L-band Array for the GBT (FLAG) project. Commissioning observations of calibrator radio sources show that this receiver has the lowest reported beam-formed system temperature (Tsys) normalized by aperture efficiency ( ) of any phased-array receiver to date. The measured Tsys/ is 25.4 2.5 K near 1350 MHz for the boresight beam, which is comparable to the performance of the current 1.4 GHz cryogenic single-feed receiver on the GBT. The degradation in Tsys/ at ∼4′ (required for Nyquist sampling) and ∼8′ offsets from the boresight is, respectively, ∼1% and ∼20% of the boresight value. The survey speed of the PAF with seven formed beams is larger by a factor between 2.1 and 7 compared to a single-beam system, depending on the observing application. The measured performance, both in frequency and offset from the boresight, qualitatively agrees with predictions from a rigorous electromagnetic model of the PAF. The astronomical utility of the receiver is demonstrated by observations of the pulsar B0329+54 and an extended H ii region, the Rosette Nebula. The enhanced survey speed with the new PAF receiver will enable the GBT to carry out exciting new science, such as more efficient observations of diffuse, extended neutral hydrogen emission from galactic inflows and searches for fast radio bursts.
We assessed intergenerational differences in food, physical activity, and body size perceptions among refugees and migrants from the Horn of Africa living in Victoria, Australia. We used a ...qualitative design and obtained data from 48 participants (18 individual interviews; 3 semistructured focus groups). Three major themes emerged: (a) food and physical activity, (b) preference of body size and social expectations, and (c) perceived consequences of various body sizes. For parents, large body size was perceived to equate with being beautiful and wealthy; slimness was associated with chronic illness and poverty. Parents adopted strategies that promoted weight gain in children. These included tailored food practices and restricting children’s involvement in physical activity. For young people, slimness was the ideal body size endorsed by their peers, and they adopted strategies to resist parental pressure to gain weight. Obesity-prevention programs in this subpopulation need to adopt a multigenerational approach.
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