The Australia SKA Pathfinder (ASKAP) is a new telescope under development as a world-class high-dynamic-range wide-field-of-view survey instrument. It will utilize focal plane phased array feeds on ...the 36 12-m antennas that will compose the array. The large amounts of data present a huge computing challenge, and ASKAP will store data products in an archive after near real-time pipeline processing. This powerful instrument will be deployed at a new radio-quiet observatory, the Murchison Radio-astronomy Observatory in the midwest region of Western Australia, to enable sensitive surveys of the entire sky to address some of the big questions in contemporary physics. As a pathfinder for the SKA, ASKAP will demonstrate field of view enhancement and computing/processing technology as well as the operation of a large-scale radio array in a remote and radio-quiet region of Australia.
ABSTRACT Current generation low-frequency interferometers constructed with the objective of detecting the high-redshift 21 cm background aim to generate power spectra of the brightness temperature ...contrast of neutral hydrogen in primordial intergalactic medium. Two-dimensional (2D) power spectra (power in Fourier modes parallel and perpendicular to the line of sight) that formed from interferometric visibilities have been shown to delineate a boundary between spectrally smooth foregrounds (known as the wedge) and spectrally structured 21 cm background emission (the EoR window). However, polarized foregrounds are known to possess spectral structure due to Faraday rotation, which can leak into the EoR window. In this work we create and analyze 2D power spectra from the PAPER-32 imaging array in Stokes I, Q, U, and V. These allow us to observe and diagnose systematic effects in our calibration at high signal-to-noise within the Fourier space most relevant to EoR experiments. We observe well-defined windows in the Stokes visibilities, with Stokes Q, U, and V power spectra sharing a similar wedge shape to that seen in Stokes I. With modest polarization calibration, we see no evidence that polarization calibration errors move power outside the wedge in any Stokes visibility to the noise levels attained. Deeper integrations will be required to confirm that this behavior persists to the depth required for EoR detection.
We report the detection of an ultra-bright fast radio burst (FRB) from a modest, 3.4-day pilot survey with the Australian Square Kilometre Array Pathfinder. The survey was conducted in a wide-field ...fly's-eye configuration using the phased-array-feed technology deployed on the array to instantaneously observe an effective area of 160 deg2, and achieve an exposure totaling 13200 deg2 hr . We constrain the position of FRB 170107 to a region in size (90% containment) and its fluence to be 58 6 Jy ms. The spectrum of the burst shows a sharp cutoff above 1400 MHz, which could be due to either scintillation or an intrinsic feature of the burst. This confirms the existence of an ultra-bright ( Jy ms) population of FRBs.
A 5-week-old male infant presented with severe bacterial infections and poor wound healing, suggesting a neutrophil defect. Neutrophils from this patient exhibited decreased chemotaxis, polarization, ...azurophilic granule secretion, and superoxide anion (O2
-) production but had normal expression and up-regulation of CD11b. Rac2, which constitutes >96% of the Rac in neutrophils, is a member of the Rho family of GTPases that regulates the actin cytoskeleton and O2
-production. Western blot analysis of lysates from patient neutrophils demonstrated decreased levels of Rac2 protein. Addition of recombinant Rac to extracts of the patient neutrophils reconstituted O2
-production in an in vitro assay system. Molecular analysis identified a point mutation in one allele of the Rac2 gene resulting in the substitution of Asp57 by an Asn (Rac2D57N). Asp57 is invariant in all defined GTP-binding proteins. Rac2D57Nbinds GDP but not GTP and inhibits oxidase activation and O2
-production in vitro. These data represent the description of an inhibitory mutation in a member of the Rho family of GTPases associated with a human immunodeficiency syndrome.
The Allen Telescope Array (ATA) is a cm-wave interferometer in California, comprising 42 antenna elements with 6-m diameter dishes. We characterize the antenna optical accuracy using two-antenna ...interferometry and radio holography. The distortion of each telescope relative to the average is small, with RMS differences of 1% of beam peak value. Holography provides images of dish illumination, characterizing as-built mirror surfaces. Maximal distortions across ~ 2 meter lengths appear to result from mounting stresses or solar radiation. Experimental RMS errors are 0.7 mm at night and 3 mm under worst-case solar illumination. For frequencies 4, 10, and 15 GHz, the nighttime values indicate sensitivity losses of 1, 10 and 20%, respectively. ATA's wide-bandwidth receiver permits observations over a continuous range 0.5-11.2 GHz. We probe the antenna optical gain and beam pattern stability as a function of focus position and observation frequency, concluding that ATA can produce high fidelity images over a decade of simultaneous observation frequencies. We quantify solar heating effects on antenna sensitivity and pointing accuracy. We find that during the day, observations >;5 GHz will suffer some sensitivity loss and it may be necessary to make antenna pointing corrections on a 1-2 hourly basis.
Background and Aims Unsedated transnasal endoscopy (TNE) is safer and less costly than sedated EGD. The aim of this study was to evaluate the performance of TNE with biopsies in monitoring the ...esophageal mucosa of pediatric patients with eosinophilic esophagitis. Methods Patients between 8 and 17 years of age with eosinophilic esophagitis and their parents were enrolled. Unsedated TNE was performed. A 2.8-mm (1.2-mm channel) or a 4-mm flexible bronchoscope (2-mm channel) was used, and esophageal biopsy specimens were obtained. Biopsy specimen analysis, duration, adverse events, and billing charges of TNE were assessed. Immediately after TNE and a minimum of 2 weeks later, a modified Group Health Association of America 9 survey and a preference questionnaire were completed, respectively. Results Twenty-one of 22 enrolled patients underwent TNE. TNE was performed with no serious adverse events. Histopathological analysis revealed 0 eosinophils per high-power field (n = 12), fewer than 15 eosinophils per high-power field (n = 4), and more than 15 eosinophils per high-power field (n = 5). The total epithelial surface area of mucosal biopsy samples from either TNE Forceps (1.2 mm or 2 mm biopsy channel forceps) compared with those obtained during the subject’s previous EGD by using standard endoscopic forceps was not statistically different ( P = .308 1.2 mm/ P = .492 2 mm). All parents and 76.2% of subjects would undergo the TNE again. TNE was preferred over EGD by 85.7% of parents and 52.4% of subjects. The modified Group Health Association of America 9 survey revealed a high degree of satisfaction (average, 43.19 ± 2.6; maximum score, 45). Charges associated with TNE were 60.1% lower than for previous EGDs. Conclusions Unsedated TNE is an effective, lower-cost procedure for monitoring the esophageal mucosa of children with eosinophilic esophagitis.
Objective To evaluate children with Crohn's disease for inverse relationships between systemic inflammatory cytokines and sex hormone regulation in the context of anti-tumor necrosis factor α (TNF-α) ...therapy. Study design An observational study design was used to assess sex hormone and gonadotropin levels at the time of initiation of anti-TNF-α therapy and 10 weeks and 12 months later in 72 adolescents (Tanner stage 2-5) with Crohn's disease. Mixed-model linear regression was used to evaluate relationships between hormone levels, systemic inflammation, and dual-energy x-ray absorptiometry whole-body fat mass Z scores over the study interval. Results Sex hormone Z scores increased significantly during the 10-week induction interval: testosterone Z scores in male patients increased from a median of −0.36 to 0.40 ( P < .05) and estradiol Z scores in females increased from −0.35 to −0.02 ( P < .01). In mixed model regression, the pediatric Crohn's disease activity index score, cytokine levels, and measures of inflammation were significantly and negatively associated with sex hormone Z scores and with luteinizing hormone and follicle-stimulating hormone levels, adjusted for sex and Tanner stage. Sex hormone and gonadotropin levels were not associated with body mass index or fat mass Z-scores. Conclusions Crohn's disease is associated with delayed maturation, and initiation of anti-TNF-α therapy was associated with significant and rapid increases in sex hormone and gonadotropin levels, in association with improvements in disease activity and measures of inflammation. These data are consistent with preclinical studies of the effects of inflammation on sex hormone regulation.
As current- and next-generation astronomical instruments come online, they will generate an unprecedented deluge of data. Analyzing these data in real time presents unique conceptual and ...computational challenges, and their long-term storage and archiving is scientifically essential for generating reliable, reproducible results. We present here the real-time processing (RTP) system for the Hydrogen Epoch of Reionization Array (HERA), a radio interferometer endeavoring to provide the first detection of the highly redshifted 21 cm signal from Cosmic Dawn and the Epoch of Reionization by an interferometer. The RTP system consists of analysis routines run on raw data shortly after they are acquired, such as calibration and detection of radio-frequency interference (RFI) events. RTP works closely with the Librarian, the HERA data storage and transfer manager which automatically ingests data and transfers copies to other clusters for post-processing analysis. Both the RTP system and the Librarian are public and open source software, which allows for them to be modified for use in other scientific collaborations. When fully constructed, HERA is projected to generate over 50 terabytes (TB) of data each night, and the RTP system enables the successful scientific analysis of these data.
Abstract Background Nutritional deficits in early life have been associated with a higher prevalence of the metabolic syndrome (MetS) in adulthood. Early childhood diarrhea contributes to ...undernutrition and may potentially increase the risk for adult noncommunicable diseases. Our objective was to examine associations between early childhood diarrhea burden and later development of MetS. Methods We studied individuals who participated in the Institute of Nutrition of Central America and Panama Nutritional Supplementation Longitudinal Study (1969–1977) and were followed up in 2002–2004. We used logistic regression to determine associations of diarrhea burden at ages 0 to 6, 6 to 12, and 12 to 24 months with odds of MetS and elevations in its components as adults. Results Among 389 adults age 25 to 42 years at follow-up, the prevalence of MetS was 29%. Adjusting for several confounders including adult body mass index (BMI), each absolute 1% increase in diarrhea burden at age 0 to 6 months (but not at other time periods) was associated with increased odds of MetS (odds ratio OR, 1.03; 95% confidence interval CI, 1.01–1.06). This was attributable primarily to associations with elevated blood pressure (OR, 1.03; 95% CI, 1.00–1.06) and waist circumference (OR, 1.03; 95% CI, 1.00–1.06). Conclusions Childhood diarrhea burden at 0 to 6 months is associated with MetS in adulthood after controlling for childhood growth parameters and adult BMI.
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