201 research outputs found
ARIS-Campaign: intercomparison of three ground based 22 GHz radiometers for middle atmospheric water vapor at the Zugspitze in winter 2009
This paper presents the Alpine Radiometer Intercomparison at the Schneefernerhaus (ARIS), which took place in winter 2009 at the high altitude station at the Zugspitze, Germany (47.42° N, 10.98° E, 2650 m). This campaign was the first direct intercomparison between three new ground based 22 GHz water vapor radiometers for middle atmospheric profiling with the following instruments participating: MIRA 5 (Karlsruhe Institute of Technology), cWASPAM3 (Max Planck Institute for Solar System Research, Katlenburg-Lindau) and MIAWARA-C (Institute of Applied Physics, University of Bern). Even though the three radiometers all measure middle atmospheric water vapor using the same rotational transition line and similar fundamental set-ups, there are major differences between the front ends, the back ends, the calibration concepts and the profile retrieval. The spectrum comparison shows that all three radiometers measure spectra without severe baseline artifacts and that the measurements are in good general agreement. The measurement noise shows good agreement to the values theoretically expected from the radiometer noise formula. At the same time the comparison of the noise levels shows that there is room for instrumental and calibration improvement, emphasizing the importance of low elevation angles for the observation, a low receiver noise temperature and an efficient calibration scheme. <br><br> The comparisons of the retrieved profiles show that the agreement between the profiles of MIAWARA-C and cWASPAM3 with the ones of MLS is better than 0.3 ppmv (6%) at all altitudes. MIRA 5 has a dry bias of approximately 0.5 ppm (8%) below 0.1 hPa with respect to all other instruments. The profiles of cWASPAM3 and MIAWARA-C could not be directly compared because the vertical region of overlap was too small. The comparison of the time series at different altitude levels show a similar evolution of the H<sub>2</sub>O volume mixing ratio (VMR) for the ground based instruments as well as the space borne sensor MLS
Relative immunocompetence of the newborn harbour seal, phoca vitulina
The immune system of many mammalian species is not fully developed at birth, with newborns obtaining temporary immunological protection from maternal antibodies. Little is known of the immune system of the harbour seal, and developmental aspects of its immune system have not been systematically studied. We collected blood and milk samples from nine free-ranging mother-pup pairs throughout the lactation period on Sable Island, Canada, in an effort to characterise developmental aspects of the immune system of this newborn pinniped. Pup lymphocytes responded stronger to the mitogens concanavalin A, phytohaemagglutinin, and pokeweed mitogen tha
Comparison of DVB-T Passive Radar Simulated and Measured Bistatic RCS Values for a Pilatus PC-12 Aircraft
Passive radar is a technology that has huge potential for airspace monitoring, taking advantage of existing transmissions. However, to predict whether particular targets can be measured in a particular scenario, it is necessary to be able to model the received signal. In this paper, we present the results of a campaign in which a Pilatus PC-12 single-engine aircraft was measured with a passive radar system relying on DVB-T transmission from a single transmitter. We then present our work to simulate the bistatic RCS of the aircraft along its flight track, using both the method of moments and the shooting and bouncing ray solvers, assess the uncertainty in the simulations, and compare against the measurements. We find that our simulated RCS values are useful in predicting whether or not detection occurs. However, we see poor agreement between simulated and measured RCS values where measurements are available, which we attribute primarily to the difficulties in extracting RCS measurements from the data and to unmodeled transmission and received path effects
Measuring prevalence and incidence of chronic conditions in claims and electronic health record databases
Jeremy A Rassen,1 Dorothee B Bartels,2 Sebastian Schneeweiss,1,3,4 Amanda R Patrick,1 William Murk1,5 1Aetion, Inc, New York, NY, USA; 2BI X GmbH, Ingelheim, Germany; 3Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women’s Hospital, Boston, MA, USA; 4Harvard Medical School, Boston, MA, USA; 5Jacobs School of Medicine, University at Buffalo, Buffalo, NY, USA Background: Health care databases are natural sources for estimating prevalence and incidence of chronic conditions, but substantial variation in estimates limits their interpretability and utility. We evaluated the effects of design choices when estimating prevalence and incidence in claims and electronic health record databases. Methods: Prevalence and incidence for five chronic diseases at increasing levels of expected frequencies, from cystic fibrosis to COPD, were estimated in the Clinical Practice Research Datalink (CPRD) and MarketScan databases from 2011 to 2014. Estimates were compared using different definitions of lookback time and contributed person-time. Results: Variation in lookback time substantially affected estimates. In 2014, for CPRD, use of an all-time vs a 1-year lookback window resulted in 4.3–8.3 times higher prevalence (depending on disease), reducing incidence by 1.9–3.3 times. All-time lookback resulted in strong temporal trends. COPD prevalence between 2011 and 2014 in MarketScan increased by 25% with an all-time lookback but stayed relatively constant with a 1-year lookback. Varying observability did not substantially affect estimates. Conclusion: This framework draws attention to the underrecognized potential for widely varying incidence and prevalence estimates, with implications for care planning and drug development. Though prevalence and incidence are seemingly straightforward concepts, careful consideration of methodology is required to obtain meaningful estimates from health care databases. Keywords: epidemiology, epidemiologic methods, epidemiological monitoring, sentinel surveillance, pharmacoepidemiology, cross-sectional studies, secondary databases, prevalence, prevalence studies, incidenc
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Wedge test data for three new explosives: LAX112, 2,4-DNI, and TNAZ
High pressure Pop-plots and inert Hugoniot curves have been measured for three new explosives: LAX112 (3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide), 2,4-DNI (2,4-dinitroimidazole), and TNAZ (1,3,3-trinitroazetidine). LAX112 and 2,4-DNI are of interest because of their insensitivity, while TNAZ is useful for its performance and castability. The shock sensitivity of LAX112 and 2,4-DNI fall between that of pressed TNT and PBX9502, LAX112 being the less sensitive. The shock sensitivity of TNAZ falls between that of pressed PETN and PBX9501. The Pop-plot and Hugoniot data for TNAZ matches well with the lower pressure gas-gun data of Sheffield, Gustavsen, and Alcon. The inert Hugoniots for all three materials are comparable to those of other explosives
Experimental validation of geosmin uptake in rainbow trout, Oncorhynchus mykiss (Waldbaum) suggests biotransformation
The bioconcentration of waterborne geosmin in rainbow trout, Oncorhynchus mykiss (Waldbaum) was assessed. Fifty rainbow trout with a mean (SD) weight of 226.6 (29.0) g and lipid content of 6.2 (0.6) % (w/w) were exposed to geosmin in static water for 0, 2, 4, 6, 8, 12, 24, 36, 48 and 120 hr, with one tank containing five fish for eac h exposure period. Geosmin concentrations were measured in fish tissue and water samples collected over time. With time the geosmin concentration in the fish increased and decreased in the water. However, the total absolute amount of geosmin in the system declined over time which could be explained by induction of biotransformation. This is in accordance with the decreasing lipid normalized geosmin levels in the liver compared with the liver-free carcass. Geosmin distribution within rainbow trout clearly is not exclusively governed by the lipid content of tissues. In vivo geosmin bioconcentration in rainbow trout is slower and the body burden reached is lower than the generally accepted theoretical model predicts
FcRn-mediated antibody transport across epithelial cells revealed by electron tomography
The neonatal Fc receptor (FcRn) transports maternal IgG across epithelial barriers, thereby providing the fetus or newborn with humoral immunity before its immune system is fully functional. In newborn rats, FcRn transfers IgG from milk to blood by apical-to-basolateral transcytosis across intestinal epithelial cells. The pH difference between the apical (pH 6.0–6.5) and basolateral (pH 7.4) sides of intestinal epithelial cells facilitates the efficient
unidirectional transport of IgG, because FcRn binds IgG at
pH 6.0–6.5 but not at pH 7 or more. As milk passes through
the neonatal intestine, maternal IgG is removed by FcRn-expressing cells in the proximal small intestine (duodenum and jejunum); remaining proteins are absorbed and degraded by FcRn-negative cells in the distal small intestine (ileum). Here we use electron tomography to make jejunal transcytosis visible directly in space and time, developing new labelling and detection methods to map individual nanogold-labelled Fc within transport
vesicles and simultaneously to characterize these vesicles by immunolabelling. Combining electron tomography with a nonperturbing endocytic label allowed us to conclusively identify receptor-bound ligands, resolve interconnecting vesicles, determine whether a vesicle was microtubule-associated, and accurately trace FcRn-mediated transport of IgG. Our results present a complex picture in which Fc moves through networks of entangled tubular and irregular vesicles, only some of which are microtubule-associated, as it migrates to the basolateral surface. New features
of transcytosis are elucidated, including transport involving multivesicular body inner vesicles/tubules and exocytosis through clathrin-coated pits. Markers for early, late and recycling endosomes each labelled vesicles in different and overlapping morphological classes, revealing spatial complexity in endo-lysosomal trafficking
Wideband 67-116 GHz cryogenic receiver development for ALMA Band 2
The Atacama Large Millimeter/sub-millimeter Array (ALMA) is already
revolutionising our understanding of the Universe. However, ALMA is not yet
equipped with all of its originally planned receiver bands, which will allow it
to observe over the full range of frequencies from 35-950 GHz accessible
through the Earth's atmosphere. In particular Band 2 (67-90 GHz) has not yet
been approved for construction. Recent technological developments in cryogenic
monolithic microwave integrated circuit (MMIC) high electron mobility
transistor (HEMT) amplifier and orthomode transducer (OMT) design provide an
opportunity to extend the originally planned on-sky bandwidth, combining ALMA
Bands 2 and 3 into one receiver cartridge covering 67-116 GHz.
The IF band definition for the ALMA project took place two decades ago, when
8 GHz of on-sky bandwidth per polarisation channel was an ambitious goal. The
new receiver design we present here allows the opportunity to expand ALMA's
wideband capabilities, anticipating future upgrades across the entire
observatory. Expanding ALMA's instantaneous bandwidth is a high priority, and
provides a number of observational advantages, including lower noise in
continuum observations, the ability to probe larger portions of an astronomical
spectrum for, e.g., widely spaced molecular transitions, and the ability to
scan efficiently in frequency space to perform surveys where the redshift or
chemical complexity of the object is not known a priori. Wider IF bandwidth
also reduces uncertainties in calibration and continuum subtraction that might
otherwise compromise science objectives.
Here we provide an overview of the component development and overall design
for this wideband 67-116 GHz cryogenic receiver cartridge, designed to operate
from the Band 2 receiver cartridge slot in the current ALMA front end receiver
cryostat.Comment: 8 pages, proceedings from the 8th ESA Workshop on Millimetre-Wave
Technology and Applications
(https://atpi.eventsair.com/QuickEventWebsitePortal/millimetre-wave/mm-wave
Rapid assessment of regional SARS-CoV-2 community transmission through a convenience sample of healthcare workers, the Netherlands, March 2020
To rapidly assess possible community transmission in Noord-Brabant, the Netherlands, healthcare workers (HCW) with mild respiratory complaints and without epidemiological link (contact with confirmed case or visited areas with active
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