363 research outputs found

    CORMASS: A Compact and Efficient NIR Spectrograph for Studying Low-Mass Objects

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    CorMASS (Cornell Massachusetts Slit Spectrograph) is a compact, low-resolution (R=300), double-pass prism cross-dispersed near-infrared (NIR) spectrograph in operation on the Palomar Observatory 60-inch telescope. Its 2-dimensional spectral format provides simultaneous coverage from lambda ~ 0.75 microns to lambda ~ 2.5 microns (z'JHK bands). A remotely operated cold flip mirror permits its NICMOS3 detector to function as a K_s slit viewer to assist object placement into the 2 arcsec x 15 arcsec slit. CorMASS was primarily designed for the rapid spectral classification of low-mass stellar and sub-stellar objects identified by the Two-Micron All Sky Survey (2MASS). CorMASS' efficiency and resolution also make it a versatile instrument for the spectral observation and classification of many other types of bright objects (K<14) including quasars, novae, and emission line objects.Comment: To be published in Feb 2001 PASP, 19 pages, 12 Figures, High Resolution file can be retrieved from ftp://iras2.tn.cornell.edu/pub/wilson/papers/cormass.ps.g

    Diagnostic methods and treatment outcomes for TB in children under 15 years in Kisii County, 2012-2016

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    Background: Diagnosis of TB in children poses a challenge due to the paucibacillairy nature of TB and difficulties in making a bacteriological confirmation. Globally, the TB burden in children is unknown with WHO estimating that they account for 10‐15% of all cases. In Kenya, children contributed to 8.5% of all notified TB cases in 2016.Objective: To describe the diagnostic methods and treatment outcomes among children aged&lt;15 years in Kisii County, 2012‐2016.Design: A descriptive analysis of children aged &lt;15 years in Kisii County diagnosed and notified of TB to the National TB program.Results: We abstracted 825 records of children:217 in 2012,156 in 2013,164 in 2014,136 in 2015 and 152 in 2016.The median age was 8(IQR 2‐13) years with a male: female of ratio 1:1. The 10‐15 years age‐group accounted for 43% (351) while those aged&lt;1year accounted for 10% (81). HIV testing was done among 806 (98%) with a TB/HIV co‐infection of 31% and 96% ART initiation rate. Bacteriological and clinical diagnosis was done for 129/825 (16%) and 696/825(84 %). Gene Xpert was done for 28/825 (3%) in 2016 and 1/825 in 2012. Overall, for the period 2012‐2015, the treatment success rate (TSR) was 96%Conclusion: There has been a decline in notification rates over time, however, it was not clear whether this was due to absence of disease or improved use of diagnostics which requires further research. Older children accounted for majority of the cases diagnosed for TB. Most of the children in the younger age groups &lt;5 years were initiated on treatment based on clinical diagnosis or a chest X‐ray and hence a need to support health workers and health system in general on acquisition of sputum specimen in this younger age group

    Discovery of a Bright Field Methane (T-type) Brown Dwarf by 2MASS

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    We report the discovery of a bright (J = 13.83±\pm0.03) methane brown dwarf, or T dwarf, by the Two Micron All Sky Survey. This object, 2MASSI J0559191-140448, is the first brown dwarf identified by the newly commissioned CorMASS instrument mounted on the Palomar 60-inch Telescope. Near-infrared spectra from 0.9 - 2.35 \micron show characteristic CH4_4 bands at 1.1, 1.3, 1.6, and 2.2 \micron, which are significantly shallower than those seen in other T dwarfs discovered to date. Coupled with the detection of an FeH band at 0.9896 \micron and two sets of K I doublets at J-band, we propose that 2MASS J0559-14 is a warm T dwarf, close to the transition between L and T spectral classes. The brightness of this object makes it a good candidate for detailed investigation over a broad wavelength regime and at higher resolution.Comment: 21 pages, 3 figures, 2 tables, accepted to AJ for publication August 200

    The ultraluminous GRB 110918A

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    GRB 110918A is the brightest long GRB detected by Konus-WIND during its 19 years of continuous observations and the most luminous GRB ever observed since the beginning of the cosmological era in 1997. We report on the final IPN localization of this event and its detailed multiwavelength study with a number of space-based instruments. The prompt emission is characterized by a typical duration, a moderare EpeakE_{peak} of the time-integrated spectrum, and strong hard-to-soft evolution. The high observed energy fluence yields, at z=0.984, a huge isotropic-equivalent energy release Eiso=(2.1±0.1)×1054E_{iso}=(2.1\pm0.1)\times10^{54} erg. The record-breaking energy flux observed at the peak of the short, bright, hard initial pulse results in an unprecedented isotropic-equivalent luminosity Liso=(4.7±0.2)×1054L_{iso}=(4.7\pm0.2)\times10^{54}erg s1^{-1}. A tail of the soft gamma-ray emission was detected with temporal and spectral behavior typical of that predicted by the synchrotron forward-shock model. Swift/XRT and Swift/UVOT observed the bright afterglow from 1.2 to 48 days after the burst and revealed no evidence of a jet break. The post-break scenario for the afterglow is preferred from our analysis, with a hard underlying electron spectrum and ISM-like circumburst environment implied. We conclude that, among multiple reasons investigated, the tight collimation of the jet must have been a key ingredient to produce this unusually bright burst. The inferred jet opening angle of 1.7-3.4 deg results in reasonable values of the collimation-corrected radiated energy and the peak luminosity, which, however, are still at the top of their distributions for such tightly collimated events. We estimate a detection horizon for a similar ultraluminous GRB of z7.5z\sim7.5 for Konus-WIND, and z12z\sim12 for Swift/BAT, which stresses the importance of GRBs as probes of the early Universe.Comment: 22 pages, 20 figures, accepted for publication in Ap

    Comparison of demographic and clinical characteristics between pulmonary and extra-pulmonary tuberculosis patients in Kiambu County, 2012-2015

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    Background: Tuberculosis (TB) continues to be a public health challenge globally. The most common organ to be involved is the lung although it can affect any organ in the body. The diagnosis of extra-pulmonary TB (EPTB) has faced many challenges mainly due to inadequate expertise to diagnose or lack of equipment for diagnosis.Objective: To compare the demographic and clinical characteristics between pulmonary and extrapulmonary tuberculosis in Kiambu CountyDesign: Retrospective cross-sectional studySetting: Kiambu County, KenyaSubjects: Tuberculosis patients notified in TIBU surveillance systemResults: Of the 15, 833 patients analyzed, 2,704 (17%) had extra-pulmonary tuberculosis. Male to female ratio was 1:1.7 in PTB and 1:1.3 in EPTB patients. There was declining trend of TB cases notified over the years for both PTB and EPTB. Pleural TB accounted for 38% with TB lymphadenitis accounting for 14% of the EPTB subtypes. TB-HIV co-infection was higher among EPTB (36%) compared to PTB (30%). The treatment success rate was 85% and 86% among PTB and EPTB cases respectively. The mortality was 10% among EPTB and 5% in PTB cases. The 5-14 age category were more likely to developing EPTB compared to PTB (AOR 4.67 95% CI (1.5-13.99). Kabete zone was most affected with EPTB (AOR 2.11(1.19-2.74) while a protective factor was observed among the HIV positive clients (AOR 0.58 (0.43 - 0.78)Conclusion: There was a general decline in cases for both EPTB and PTB. However, the age category most affected was 5-14 years. The co-infectivity rate was higher among the EPTB patients compared to the PTB patients. High index of suspicion and appropriate diagnostic tools are needed in evaluation particularly in EPTB which will assist in early management of the patients. ART uptake could play a big role in protecting HIV positive clients from getting EPTB

    New species longevity record for the northern quahog (=hard clam), Mercenaria mercenaria

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    Author Posting. © National Shellfisheries Association, 2011. This article is posted here by permission of National Shellfisheries Association for personal use, not for redistribution. The definitive version was published in Journal of Shellfish Research 30 (2011): 35-38, doi:10.2983/035.030.0106.Twenty-two large shells (>90 mm shell height) from a sample of live collected hard shell clams, Mercenaria mercenaria, from Buzzards Bay, Woods Hole, Cape Cod, MA, were subjected to sclerochronological analysis. Annually resolved growth lines in the hinge region and margin of the shell were identified and counted; the age of the oldest clam shell was determined to be at least 106 y. This age represents a considerable increase in the known maximum life span for M. mercenaria, more than doubling the maximum recorded life span of the species (46 y). More than 85% of the clam shells aged had more than 46 annual increments, the previous known maximum life span for the species. In this article we present growth rate and growth performance indicators (the overall growth performance and phi prime) for this record-breaking population of M. mercenaria. Recently discovered models of aging require accurate age records and growth parameters for bivalve populations if they are to be utilized to their full potential.This work was supported by grants from the American Diabetes Association (to Z. U.), American Federation for Aging Research (to A. C.), the University of Oklahoma College of Medicine Alumni Association (to A. C.), the BBSRC (to C. A. R.),the National Institutes of Health (AT006526 and HL077256 to Z. U.; AG022873 and AG025063 to S. N. A.), and the DFG Cluster of Excellence ‘‘Future Ocean’’ (to E. P.)

    Verticalization of bacterial biofilms

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    Biofilms are communities of bacteria adhered to surfaces. Recently, biofilms of rod-shaped bacteria were observed at single-cell resolution and shown to develop from a disordered, two-dimensional layer of founder cells into a three-dimensional structure with a vertically-aligned core. Here, we elucidate the physical mechanism underpinning this transition using a combination of agent-based and continuum modeling. We find that verticalization proceeds through a series of localized mechanical instabilities on the cellular scale. For short cells, these instabilities are primarily triggered by cell division, whereas long cells are more likely to be peeled off the surface by nearby vertical cells, creating an "inverse domino effect". The interplay between cell growth and cell verticalization gives rise to an exotic mechanical state in which the effective surface pressure becomes constant throughout the growing core of the biofilm surface layer. This dynamical isobaricity determines the expansion speed of a biofilm cluster and thereby governs how cells access the third dimension. In particular, theory predicts that a longer average cell length yields more rapidly expanding, flatter biofilms. We experimentally show that such changes in biofilm development occur by exploiting chemicals that modulate cell length.Comment: Main text 10 pages, 4 figures; Supplementary Information 35 pages, 15 figure

    Route of feeding as a proxy for dysphagia after stroke and the effect of transdermal glyceryl trinitrate: data from the efficacy of nitric oxide in stroke randomised controlled trial

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    Post-stroke dysphagia is common, associated with poor outcome and often requires non-oral feeding/fluids. The relationship between route of feeding and outcome, as well as treatment with glyceryl trinitrate (GTN), was studied prospectively. The Efficacy of Nitric Oxide in Stroke (ENOS) trial assessed transdermal GTN (5 mg versus none for 7 days) in 4011 patients with acute stroke and high blood pressure. Feeding route (oral = normal or soft diet; nonoral = nasogastric tube, percutaneous endoscopic gastrostomy tube, parenteral fluids, no fluids) was assessed at baseline and day 7. The primary outcome was the modified Rankin Scale (mRS) measured at day 90. At baseline, 1331 (33.2%) patients had non-oral feeding, were older, had more severe stroke and more were female, than 2680 (66.8%) patients with oral feeding. By day 7, 756 patients had improved from non-oral to oral feeding, and 119 had deteriorated. Non-oral feeding at baseline was associated with more impairment at day 7 (Scandinavian Stroke Scale 29.0 versus 43.7; 2p < 0.001), and worse mRS (4.0 versus 2.7; 2p < 0.001) and death (23.6 versus 6.8%; 2p = 0.014) at day 90. Although GTN did not modify route of feeding overall, randomisation ≤6 hours of stroke was associated with a move to more oral feeding at day 7 (odds ratio = 0.61, 95% confidence intervals 0.38, 0.98; 2p = 0.040). As a proxy for dysphagia, non-oral feeding is present in 33% of patients with acute stroke and associated with more impairment, dependency and death. GTN moved feeding route towards oral intake if given very early after stroke

    Loss of tolerance precedes triggering and lifelong persistence of pathogenic type I interferon autoantibodies.

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    Autoantibodies neutralizing type I interferons (IFN-Is) can underlie infection severity. Here, we trace the development of these autoantibodies at high-resolution using longitudinal samples from 1,876 well-treated individuals living with HIV over a 35-year period. Similar to general populations, ∼1.9% of individuals acquired anti-IFN-I autoantibodies as they aged (median onset ∼63 years). Once detected, anti-IFN-I autoantibodies persisted lifelong, and titers increased over decades. Individuals developed distinct neutralizing and non-neutralizing autoantibody repertoires at discrete times that selectively targeted combinations of IFNα, IFNβ, and IFNω. Emergence of neutralizing anti-IFNα autoantibodies correlated with reduced baseline IFN-stimulated gene levels and was associated with subsequent susceptibility to severe COVID-19 several years later. Retrospective measurements revealed enrichment of pre-existing autoreactivity against other autoantigens in individuals who later developed anti-IFN-I autoantibodies, and there was evidence for prior viral infections or increased IFN at the time of anti-IFN-I autoantibody triggering. These analyses suggest that age-related loss of self-tolerance prior to IFN-I immune-triggering poses a risk of developing lifelong functional IFN-I deficiency
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