527 research outputs found

    Over-utilization of Advanced Imaging in the Hospital Setting: An Educational Approach to Reduce Unnecessary Inpatient Studies

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    By several measures, health care spending continues to rise, forcing businesses and families to cut back on operations and household expenses. In 2008, health care spending in the United States reached 2.4trilliondollars,andisprojectedtoreach2.4 trillion dollars, and is projected to reach 3.1 trillion in 2012.During the past decades, there has been a steady increase in the utilization of expensive inpatient imaging studies, with an overall increase in health care costs. In particular, advanced imaging includes CT, MRI and Nuclear Medicine, used for the diagnosis and management of hospitalized patients. The reasons for unnecessary imaging examinations include indirect financial benefit to physicians, medico-legal considerations, lack of accepted guidelines or failure to follow established ones. In the United States alone, it is estimated that CT testing accounts for around 6,000 additional cancers per year, with about half of those proving fatal. Each radiologic study using gadolinium presented a 2.4% risk of developing nephrogenic systemic fibrosis, with significant morbidity and mortality. We have shown that education of the ordering physicians is a feasible and cost effective means to decrease the over-otilization of advanced imaging in the inpatient setting

    Optical properties of cirrus derived from airborne measurements during FIRE IFO 2

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    The Radiation Measurement System (RAMS) on board the NASA ER-2 was used to acquire several optical parameters of interest during the FIRE Cirrus IFO 2. In this abstract we present results from the 26 Nov. IFO when the ER-2 flew over the Coffeyville airport hub site. We show retrieved optical thickness and cloud temperature, along with optical thickness obtained from RAMS instruments on the NCAR Sabreliner and at the surface site B. Independent retrieval of optical thickness, from the ER-2 and at the surface, are in agreement during the overpasses. Cirrus optical depths, derived from each platform, ranged between 1 and 2

    Quantifying the Impacts of Subpixel Reflectance Variability on Cloud Optical Thickness and Effective Radius Retrievals Based On HighResolution ASTER Observations

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    TOOLS SHAREAbstractRecently, Zhang et al. (2016) presented a mathematical framework based on a secondorder Taylor series expansion in order to quantify the planeparallel homogeneous bias (PPHB) in cloud optical thickness () and effective droplet radius (r(sub eff)) retrieved from the bispectral solar reflective method. This study provides observational validation of the aforementioned framework, using highresolution reflectance observations from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) over 48 marine boundary layer cloud scenes. ASTER reflectances at a horizontal resolution of 30 m are aggregated up to a scale of 1,920 m, providing retrievals of and r(sub eff) at different spatial resolutions. A comparison between the PPHB derived from these retrievals and the predicted PPHB from the mathematical framework reveals a good agreement with correlation coefficients of r > 0.97 (for ) and r > 0.79 (for r(sub eff)). To test the feasibility of PPHB predictions for present and future satellite missions, a scale analysis with varying horizontal resolutions of the subpixel and pixellevel observations is performed, followed by tests of corrections with only limited observational highresolution data. It is shown that for reasonably thick clouds with a mean subpixel larger than 5, correlations between observed and predicted PPHB remain high, even if the number of available subpixels decreases or just a single band provides the information about subpixel reflectance variability. Only for thin clouds the predicted r(sub eff) become less reliable, which can be attributed primarily to an increased retrieval uncertainty for r(sub eff)

    Accurate satellite-derived estimates of the tropospheric ozone impact on the global radiation budget

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    Estimates of the radiative forcing due to anthropogenically-produced tropospheric O3 are derived primarily from models. Here, we use tropospheric ozone and cloud data from several instruments in the A-train constellation of satellites as well as information from the GEOS-5 Data Assimilation System to accurately estimate the radiative effect of tropospheric O3 for January and July 2005. Since we cannot distinguish between natural and anthropogenic sources with the satellite data, our derived radiative effect reflects the unadjusted (instantaneous) effect of the total tropospheric O3 rather than the anthropogenic component. We improve upon previous estimates of tropospheric ozone mixing ratios from a residual approach using the NASA Earth Observing System (EOS) Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) by incorporating cloud pressure information from OMI. We focus specifically on the magnitude and spatial structure of the cloud effect on both the short- and long-wave radiative budget. The estimates presented here can be used to evaluate the various aspects of model-generated radiative forcing. For example, our derived cloud impact is to reduce the radiative effect of tropospheric ozone by ~16%. This is centered within the published range of model-produced cloud effect on unadjusted ozone radiative forcing

    A revision of the American spiders of the family Microstigmatidae (Araneae, Mygalomorphae). American Museum novitates ; no. 2707

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    20 p. : ill. ; 26 cm.Includes bibliographical references (p. 20)."The tribal grouping Microstigmateae Roewer is removed from the Dipluridae and elevated to familial rank. The subfamily Pseudonemesiinae Caporiacco is transferred from the Ctenizidae to the Microstigmatidae. The family is suggested to be the sister group of the Mecicobothriidae plus Hexalethidae and Dipluridae. The male of the Venezuelan species Pseudonemesia parva Caporiacco is descibed for the first time, and a new species, P. kochalkai, is described from Colombia. A genus (Ministigmata) described for a new species (M. minuta) from Brazil is hypothesized to be more closely related to the South African genus Microstigmata than to Pseudonemesia"--P. [1]

    Detection of Multi-Layer and Vertically-Extended Clouds Using A-Train Sensors

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    The detection of mUltiple cloud layers using satellite observations is important for retrieval algorithms as well as climate applications. In this paper, we describe a relatively simple algorithm to detect multiple cloud layers and distinguish them from vertically-extended clouds. The algorithm can be applied to coincident passive sensors that derive both cloud-top pressure from the thermal infrared observations and an estimate of solar photon pathlength from UV, visible, or near-IR measurements. Here, we use data from the A-train afternoon constellation of satellites: cloud-top pressure, cloud optical thickness, the multi-layer flag from the Aqua MODerate-resolution Imaging Spectroradiometer (MODIS) and the optical centroid cloud pressure from the Aura Ozone Monitoring Instrument (OMI). For the first time, we use data from the CloudSat radar to evaluate the results of a multi-layer cloud detection scheme. The cloud classification algorithms applied with different passive sensor configurations compare well with each other as well as with data from CloudSat. We compute monthly mean fractions of pixels containing multi-layer and vertically-extended clouds for January and July 2007 at the OMI spatial resolution (l2kmx24km at nadir) and at the 5kmx5km MODIS resolution used for infrared cloud retrievals. There are seasonal variations in the spatial distribution of the different cloud types. The fraction of cloudy pixels containing distinct multi-layer cloud is a strong function of the pixel size. Globally averaged, these fractions are approximately 20% and 10% for OMI and MODIS, respectively. These fractions may be significantly higher or lower depending upon location. There is a much smaller resolution dependence for fractions of pixels containing vertically-extended clouds (approx.20% for OMI and slightly less for MODIS globally), suggesting larger spatial scales for these clouds. We also find higher fractions of vertically-extended clouds over land as compared with ocean, particularly in the tropics and summer hemisphere

    Reconciling Simulated and Observed Views of Clouds: MODIS, ISCCP, and the Limits or Instrument Simulators

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    The properties of clouds that may be observed by satellite instruments, such as optical depth and cloud top pressure, are only loosely related to the way clouds m-e represented in models of the atmosphere. One way to bridge this gap is through "instrument simulators," diagnostic tools that map the model representation to synthetic observations so that differences between simulator output and observations can be interpreted unambiguously as model error. But simulators may themselves be restricted by limited information available from the host model or by internal assumptions. This paper considers the extent to which instrument simulators are able to capture essential differences between MODIS and ISCCP, two similar but independent estimates of cloud properties. The authors review the measurements and algorithms underlying these two cloud climatologies, introduce a MODIS simulator, and detail data sets developed for comparison with global models using ISCCP and MODIS simulators, In nature MODIS observes less mid-level doudines!> than ISCCP, consistent with the different methods used to determine cloud top pressure; aspects of this difference are reproduced by the simulators running in a climate modeL But stark differences between MODIS and ISCCP observations of total cloudiness and the distribution of cloud optical thickness can be traced to different approaches to marginal pixels, which MODIS excludes and ISCCP treats as homogeneous. These pixels, which likely contain broken clouds, cover about 15 k of the planet and contain almost all of the optically thinnest clouds observed by either instrument. Instrument simulators can not reproduce these differences because the host model does not consider unresolved spatial scales and so can not produce broken pixels. Nonetheless, MODIS and ISCCP observation are consistent for all but the optically-thinnest clouds, and models can be robustly evaluated using instrument simulators by excluding ambiguous observations
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