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100 result(s) for "Freese, K"
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A Constraint on Primordial B-modes from the First Flight of the Spider Balloon-borne Telescope
We present the first linear polarization measurements from the 2015 long-duration balloon flight of Spider, which is an experiment that is designed to map the polarization of the cosmic microwave background (CMB) on degree angular scales. The results from these measurements include maps and angular power spectra from observations of 4.8% of the sky at 95 and 150 GHz, along with the results of internal consistency tests on these data. While the polarized CMB anisotropy from primordial density perturbations is the dominant signal in this region of sky, Galactic dust emission is also detected with high significance. Galactic synchrotron emission is found to be negligible in the Spider bands. We employ two independent foreground-removal techniques to explore the sensitivity of the cosmological result to the assumptions made by each. The primary method uses a dust template derived from Planck data to subtract the Galactic dust signal. A second approach, which constitutes a joint analysis of Spider and Planck data in the harmonic domain, assumes a modified-blackbody model for the spectral energy distribution of the dust with no constraint on its spatial morphology. Using a likelihood that jointly samples the template amplitude and r parameter space, we derive 95% upper limits on the primordial tensor-to-scalar ratio from Feldman–Cousins and Bayesian constructions, finding r < 0.11 and r < 0.19, respectively. Roughly half the uncertainty in r derives from noise associated with the template subtraction. New data at 280 GHz from Spider’s second flight will complement the Planck polarization maps, providing powerful measurements of the polarized Galactic dust emission.
Analysis of Polarized Dust Emission Using Data from the First Flight of SPIDER
Using data from the first flight of Spider and from the Planck High Frequency Instrument, we probe the properties of polarized emission from interstellar dust in the Spider observing region. Component-separation algorithms operating in both the spatial and harmonic domains are applied to probe their consistency and to quantify modeling errors associated with their assumptions. Analyses of diffuse Galactic dust emission spanning the full Spider region demonstrate (i) a spectral energy distribution that is broadly consistent with a modified-blackbody (MBB) model with a spectral index of β d = 1.45 ± 0.05 (1.47 ± 0.06) for E (B)-mode polarization, slightly lower than that reported by Planck for the full sky; (ii) an angular power spectrum broadly consistent with a power law; and (iii) no significant detection of line-of-sight polarization decorrelation. Tests of several modeling uncertainties find only a modest impact (∼10% in σ r ) on Spider’s sensitivity to the cosmological tensor-to-scalar ratio. The size of the Spider region further allows for a statistically meaningful analysis of the variation in foreground properties within it. Assuming a fixed dust temperature T d = 19.6 K, an analysis of two independent subregions of that field results in inferred values of β d = 1.52 ± 0.06 and β d = 1.09 ± 0.09, which are inconsistent at the 3.9σ level. Furthermore, a joint analysis of Spider and Planck 217 and 353 GHz data within one subregion is inconsistent with a simple MBB at more than 3σ, assuming a common morphology of polarized dust emission over the full range of frequencies. This evidence of variation may inform the component-separation approaches of future cosmic microwave background polarization experiments.
280 GHz Focal Plane Unit Design and Characterization for the Spider-2 Suborbital Polarimeter
We describe the construction and characterization of the 280 GHz bolometric focal plane units (FPUs) to be deployed on the second flight of the balloon-borne Spider instrument. These FPUs are vital to Spider ’s primary science goal of detecting or placing an upper limit on the amplitude of the primordial gravitational wave signature in the cosmic microwave background (CMB) by constraining the B -mode contamination in the CMB from Galactic dust emission. Each 280 GHz focal plane contains a 16 × 16 grid of corrugated silicon feedhorns coupled to an array of aluminum–manganese transition-edge sensor (TES) bolometers fabricated on 150 mm diameter substrates. In total, the three 280 GHz FPUs contain 1530 polarization-sensitive bolometers (765 spatial pixels) optimized for the low loading environment in flight and read out by time-division SQUID multiplexing. In this paper, we describe the mechanical, thermal, and magnetic shielding architecture of the focal planes and present cryogenic measurements which characterize yield and the uniformity of several bolometer parameters. The assembled FPUs have high yields, with one array as high as 95% including defects from wiring and readout. We demonstrate high uniformity in device parameters, finding the median saturation power for each TES array to be ∼ 3 pW at 300 mK with a less than 6% variation across each array at 1 σ . These focal planes will be deployed alongside the 95 and 150 GHz telescopes in the Spider -2 instrument, slated to fly from McMurdo Station in Antarctica in December 2018.
Acute Liver Failure Secondary to Niacin Toxicity
A 17-year-old male was transferred to the pediatric intensive care unit for evaluation of acute liver failure. He was recently released from an alcohol treatment center with acute onset of chest pain. Cardiac workup was negative but he was found to have abnormal coagulation studies and elevated liver transaminases. Other evaluations included a normal toxicology screen and negative acetaminophen level. Autoimmune and infectious workups were normal providing no identifiable cause of his acute liver failure. He initially denied any ingestions or illicit drug use but on further query he admitted taking niacin in an attempt to obscure the results of an upcoming drug test. Niacin has been touted on the Internet as an aid to help pass urine drug tests though there is no evidence to support this practice. Niacin toxicity has been associated with serious multisystem organ failure and fulminant hepatic failure requiring liver transplantation. Pediatric providers should be aware of the risks associated with niacin toxicity and other experimental medical therapies that may be described on the Internet or other nonreputable sources.
Clinical Characteristics of Eosinophilic Esophagitis in Children
Objectives: The role of eosinophilic esophagitis (EE) in aerodigestive tract disorders in children is underestimated and overlooked, primarily because of a lack of understanding of this disorder by otolaryngologists. We sought to better characterize the clinical presentation of EE in order to increase awareness among otolaryngologists. Methods: We retrospectively reviewed 71 children with biopsy-proven EE to determine the most common symptoms and laboratory findings that should increase the clinical suspicion of EE. Results: Dysphagia, food impaction, and emesis were the most common symptoms in children with EE. Asthma was the most common airway diagnosis. Rhinosinusitis was the most common otolaryngological diagnosis. Food allergy was present in 60% of the children tested. Eighty-three percent of the children with elevated immunoglobulin E levels had thick linear streaking or patchy white exudate of the esophagus seen on esophagoscopy. Other major medical comorbidities existed in more than half of the children with EE, of which psychiatric disorders and other disorders of the aerodigestive tract were the most common. Conclusions: Eosinophilic esophagitis may contribute to treatment failure in patients with common and complicated aerodigestive tract disorders. To encourage clinicians to avoid overlooking the diagnosis, we present an evaluative algorithm to increase the suspicion of this entity.
SPIDER: CMB Polarimetry from the Edge of Space
Spider is a balloon-borne instrument designed to map the polarization of the millimeter-wave sky at large angular scales. Spider targets the B -mode signature of primordial gravitational waves in the cosmic microwave background (CMB), with a focus on mapping a large sky area with high fidelity at multiple frequencies. Spider ’s first long-duration balloon (LDB) flight in January 2015 deployed a total of 2400 antenna-coupled transition-edge sensors (TESs) at 90 GHz and 150 GHz. In this work we review the design and in-flight performance of the Spider instrument, with a particular focus on the measured performance of the detectors and instrument in a space-like loading and radiation environment. Spider ’s second flight in December 2018 will incorporate payload upgrades and new receivers to map the sky at 285 GHz, providing valuable information for cleaning polarized dust emission from CMB maps.
A population-based study of the frequency of corticosteroid resistance and dependence in pediatric patients with Crohn's disease and ulcerative colitis
BackgroundThe goal of this study was to examine the 1-year outcome after the first course of systemic corticosteroids in an inception cohort of pediatric patients with inflammatory bowel disease.MethodsAll Olmsted County (Minnesota) residents diagnosed with Crohn's disease (n = 50) or ulcerative colitis (n = 36) before 19 years of age from 1940 to 2001 were identified. Outcomes at 30 days and 1 year after the initial course of corticosteroids were recorded.ResultsTwenty-six patients with Crohn's disease (65%) and 14 with ulcerative colitis (44%) were treated with corticosteroids before age 19. Thirty-day outcomes for corticosteroid-treated Crohn's disease were complete remission in 16 (62%), partial remission in 7 (27%), and no response in 3 (12%), with 2 of these patients requiring surgery. Thirty-day outcomes for treated ulcerative colitis were complete remission in 7 (50%), partial remission in 4 (29%), and no response in 3 (21%). One-year outcomes for Crohn's disease were prolonged response in 11 (42%) and corticosteroid dependence in 8 (31%), whereas 7 (27%) were postsurgical. One-year outcomes for ulcerative colitis were prolonged response in 8 (57%) and corticosteroid dependence in 2 (14%), whereas 4 (29%) were postsurgical.ConclusionsMost pediatric patients with inflammatory bowel disease initially responded to corticosteroids. However, after 1 year, 58% of pediatric patients with Crohn's disease and 43% of pediatric patients with ulcerative colitis either were steroid dependent or required surgery. This finding emphasizes the need for early steroid-sparing medications in pediatric inflammatory bowel disease.
A Simulation-based Method for Correcting Mode Coupling in CMB Angular Power Spectra
Modern cosmic microwave background (CMB) analysis pipelines regularly employ complex time-domain filters, beam models, masking, and other techniques during the production of sky maps and their corresponding angular power spectra. However, these processes can generate couplings between multipoles from the same spectrum and from different spectra, in addition to the typical power attenuation. Within the context of pseudo-C ℓ based, MASTER-style analyses, the net effect of the time-domain filtering is commonly approximated by a multiplicative transfer function, F ℓ , that can fail to capture mode mixing and is dependent on the spectrum of the signal. To address these shortcomings, we have developed a simulation-based spectral correction approach that constructs a two-dimensional transfer matrix, Jℓℓ′ , which contains information about mode mixing in addition to mode attenuation. We demonstrate the application of this approach on data from the first flight of the Spider balloon-borne CMB experiment.
In-Flight Gain Monitoring of SPIDER’s Transition-Edge Sensor Arrays
Experiments deploying large arrays of transition-edge sensors (TESs) often require a robust method to monitor gain variations with minimal loss of observing time. We propose a sensitive and non-intrusive method for monitoring variations in TES responsivity using small square waves applied to the TES bias. We construct an estimator for a TES’s small-signal power response from its electrical response that is exact in the limit of strong electrothermal feedback. We discuss the application and validation of this method using flight data from SPIDER, a balloon-borne telescope that observes the polarization of the cosmic microwave background with more than 2000 TESs. This method may prove useful for future balloon- and space-based instruments, where observing time and ground control bandwidth are limited.
Replication of Epstein–Barr Virus within the Epithelial Cells of Oral Hairy Leukoplakia, an AIDS-Associated Lesion
We conducted a study to identify the viruses in tissue specimens of oral \"hairy\" leukoplakia, a lesion that is found in immunosuppressed male homosexuals and that is associated with the subsequent development of the acquired immunodeficiency syndrome. When stained for papillomavirus core antigen, 49 of 67 biopsy specimens (73 per cent) yielded positive results in epithelial-cell nuclei. Electron microscopy showed papillomavirus-like particles in all of 25 specimens, and the herpes-type virus described in a previous report was seen in 23 of the 25 specimens. Three specimens had both types of particle in the same individual epithelial cells. Immunofluorescence for herpes simplex virus, Varicella Zoster virus, and cytomegalovirus gave negative results in all cases, but 19 of 20 specimens showed intense nuclear staining in epithelial cells for the viral capsid antigen of Epstein-Barr virus (EBV). DNA hybridization using EBV probes in Southern blots demonstrated EBV DNA in all of 13 specimens and found 200 or more viral DNA molecules per cellular genome in 11 of the 13. The whole EBV genome was also demonstrated in the specimens and found to be in linear virion form. We conclude that EBV replicates within the epithelial cells In hairy leukoplakia. (N Engl J Med 1985; 313:1564–71.) VIRAL leukoplakia of the tongue in immunosuppressed male homosexuals (oral \"hairy\" leukoplakia) is a newly described lesion that is associated with the subsequent development of the features of the acquired immunodeficiency syndrome (AIDS), most often with Pneumocystis carinii pneumonia. The clinical appearance is of a slightly raised, poorly demarcated lesion with a corrugated or \"hairy\" surface. The lesions range from a few millimeters to 3.5 by 2 cm in size, they do not rub off, and they usually produce no symptoms. Initial studies suggested that the lesions contained papillomavirus as well as a virus of the herpes group. 1 In this . . .