bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding the Importance of Microphysics and Macrophysics for Warm Rain in Marine Low Clouds. Part II: Heuristic Models of Rain Formation
Authors: Wood Robert , Kubar Terence L. , Hartmann Dennis L. 
Published: May 2009

Abstract
Two simple heuristic model formulations for warm rain formation are introduced and their behavior explored. The first, which is primarily aimed at representing warm rain formation in shallow convective clouds, is a continuous collection model that uses an assumed cloud droplet size distribution consistent with observations as the source of embryonic drizzle drops that are then allowed to fall through a fixed cloud, accreting cloud droplets. The second, which is applicable to steady-state precipitation formation in stratocumulus, is a simple two-moment bulk autoconversion and accretion model in which cloud liquid water is removed by drizzle formation and replenished on a externally specified time scale that reflects the efficacy of turbulent overturning that characterizes stratocumulus.
The models’ behavior is shown to be broadly consistent with observations from the A-Train constellation of satellites, allowing the authors to explore reasons for changing model sensitivity to microphysical and macrophysical cloud properties. The models are consistent with one another, and with the observations, in that they demonstrate that the sensitivity of rain rate to cloud droplet concentration Nd (which here represents microphysical influence) is greatest for weakly precipitating clouds (i.e., for low cloud liquid water path and/or high Nd). For the steady-state model, microphysical sensitivity is shown to strongly decrease with the ratio of replenishment to drizzle time scales. Thus, rain from strongly drizzling and/or weakly replenished clouds shows low sensitivity to microphysics. This is essentially because most precipitation in these clouds is forming via accretion rather than autoconversion. For the continuous-collection model, as cloud liquid water content increases, the precipitation rate becomes more strongly controlled by the availability of cloud liquid water than by the initial embryo size or by the cloud droplet size. The models help to explain why warm rain in marine stratocumulus clouds is sensitive to Nd but why precipitation from thicker cumulus clouds appears to be less so.
Aerosol-Induced Large-Scale Variability in Precipitation over the Tropical Atlantic
Authors: Huang Jingfeng , Zhang Chidong , Prospero Joseph M. 
Published: May 2009

Abstract
Multiyear satellite observations are used to document a relationship between the large-scale variability in precipitation over the tropical Atlantic and aerosol traced to African sources. During boreal winter and spring there is a significant reduction in precipitation south of the Atlantic marine intertropical convergence zone (ITCZ) during months when aerosol concentrations are anomalously high over a large domain of the tropical Atlantic Ocean. This reduction cannot be linearly attributed to known climate factors such as El Niño–Southern Oscillation, the North Atlantic Oscillation, and zonal and meridional modes of tropical Atlantic sea surface temperature or to meteorological factors such as water vapor. The fractional variance in precipitation related to aerosol is about 12% of the total interannual variance, which is of the same order of magnitude as that related to each of the known climate and weather factors. A backward trajectory analysis confirms the African origin of aerosols that directly affect the changes in precipitation. The reduction in mean precipitation mainly comes from decreases in moderate rain rates (10–20 mm day−1), while light rain (&lt;10 mm day−1) can fluctuate in the opposite direction. The results cannot be readily explained in terms of wet deposition or uncertainties in satellite retrievals, and suggest that the observations demonstrate clearly identifiable effects of African aerosol on large-scale variability in precipitation in the tropical Atlantic region.
SnowSTAR2002 Transect Reconstruction Using a Multilayered Energy and Mass Balance Snow Model
Authors: Shi Xiaogang , Sturm Matthew , Liston Glen E. , Jordan Rachel E. , Lettenmaier Dennis P. 
Published: May 2009

Abstract
The lateral and vertical variability of snow stratigraphy was investigated through the comparison of the measured profiles of snow density, temperature, and grain size obtained during the Snow Science Traverse—Alaska Region (SnowSTAR2002) 1200-km transect from Nome to Barrow with model reconstructions from the Snow Thermal Model (SNTHERM), a multilayered energy and mass balance snow model. Model profiles were simulated at the SnowSTAR2002 observation sites using the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) as meteorological forcing. ERA-40 precipitation was rescaled so that the total snow water equivalent (SWE) on the SnowSTAR2002 observation dates equaled the observed values. The mean absolute error (MAE) of measured and simulated snow properties shows that SNTHERM was able to produce good simulations for snowpack temperature but larger errors for grain size and density. A spatial similarity analysis using semivariograms of measured profiles shows that there is diverse lateral and vertical variability for snow properties along the SnowSTAR2002 transect resulting from differences in initial snow deposition, influenced by wind, vegetation, topography, and postdepositional mechanical and thermal metamorphism. The correlation length in snow density (42 km) is quite low, whereas it is slightly longer for snow grain size (125 km) and longer still for snow temperature (130 km). An important practical question that the observed and reconstructed profiles allow to be addressed is the implications of model errors in the observed snow properties for simulated microwave emissions signatures. The Microwave Emission Model for Layered Snowpacks (MEMLS) was used to simulate 19- and 37-GHz brightness temperatures. Comparison of SNTHERM–MEMLS and SnowSTAR2002–MEMLS brightness temperatures showed a very good match occurs at 19 GHz [a root-mean-square error (RMSE) of 1.5 K (8.7 K) for vertical (horizontal) polarization] and somewhat larger [5.9 K (6.2 K) for vertical (horizontal) polarization] at 37 GHz. These results imply that the simulation of snow microphysical profiles is a viable strategy for passive microwave satellite–based retrievals of SWE.
On the Existence of Water Turbulence Induced by Nonbreaking Surface Waves
Authors: Babanin Alexander V. , Haus Brian K. 
Published: May 2009

Abstract
This paper is dedicated to wave-induced turbulence unrelated to wave breaking. The existence of such turbulence has been foreshadowed in a number of experimental, theoretical, and numerical studies. The current study presents direct measurements of this turbulence. The laboratory experiment was conducted by means of particle image velocimetry, which allowed estimates of wavenumber velocity spectra beneath monochromatic nonbreaking unforced waves. Observed spectra intermittently exhibited the Kolmogorov interval associated with the presence of isotropic turbulence. The magnitudes of the energy dissipation rates due to this turbulence in the particular case of 1.5-Hz deep-water waves were quantified as a function of the surface wave amplitude. The presence of such turbulence, previously not accounted for, can affect the physics of the wave energy dissipation, the subsurface boundary layer, and the ocean mixing in a significant way.
The CALIPSO Automated Aerosol Classification and Lidar Ratio Selection Algorithm
Authors: Omar Ali H. , Winker David M. , Vaughan Mark A. , Hu Yongxiang , Trepte Charles R. , Ferrare Richard A. , Lee Kam-Pui , Hostetler Chris A. , Kittaka Chieko , Rogers Raymond R. , Kuehn Ralph E. , Liu Zhaoyan 
Published: May 2009

Abstract
Descriptions are provided of the aerosol classification algorithms and the extinction-to-backscatter ratio (lidar ratio) selection schemes for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) aerosol products. One year of CALIPSO level 2 version 2 data are analyzed to assess the veracity of the CALIPSO aerosol-type identification algorithm and generate vertically resolved distributions of aerosol types and their respective optical characteristics. To assess the robustness of the algorithm, the interannual variability is analyzed by using a fixed season (June–August) and aerosol type (polluted dust) over two consecutive years (2006 and 2007). The CALIPSO models define six aerosol types: clean continental, clean marine, dust, polluted continental, polluted dust, and smoke, with 532-nm (1064 nm) extinction-to-backscatter ratios Sa of 35 (30), 20 (45), 40 (55), 70 (30), 65 (30), and 70 (40) sr, respectively. This paper presents the global distributions of the CALIPSO aerosol types, the complementary distributions of integrated attenuated backscatter, and the volume depolarization ratio for each type. The aerosol-type distributions are further partitioned according to surface type (land/ocean) and detection resolution (5, 20, and 80 km) for optical and spatial context, because the optically thick layers are found most often at the smallest spatial resolution. Except for clean marine and polluted continental, all the aerosol types are found preferentially at the 80-km resolution. Nearly 80% of the smoke cases and 60% of the polluted dust cases are found over water, whereas dust and polluted continental cases are found over both land and water at comparable frequencies. Because the CALIPSO observables do not sufficiently constrain the determination of the aerosol, the surface type is used to augment the selection criteria. Distributions of the total attenuated color ratios show that the use of surface type in the typing algorithm does not result in abrupt and artificial changes in aerosol type or extinction.
Temporal Changes in Wind as Objects for Evaluating Mesoscale Numerical Weather Prediction
Authors: Rife Daran L. , Davis Christopher A. , Knievel Jason C. 
Published: May 2009

AbstractThe study describes a method of evaluating numerical weather prediction models by comparing the characteristics of temporal changes in simulated and observed 10-m (AGL) winds. The method is demonstrated on a 1-yr collection of 1-day simulations by the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) over southern New Mexico. Temporal objects, or wind events, are defined at the observation locations and at each grid point in the model domain as vector wind changes over 2 h. Changes above the uppermost quartile of the distributions in the observations and simulations are empirically classified as significant; their attributes are analyzed and interpreted.It is demonstrated that the model can discriminate between large and modest wind changes on a pointwise basis, suggesting that many forecast events have an observational counterpart. Spatial clusters of significant wind events are highly continuous in space and time. Such continuity suggests that displaying maps of surface wind changes with high temporal resolution can alert forecasters to the occurrence of important phenomena. Documented systematic errors in the amplitude, direction, and timing of wind events will allow forecasters to mentally adjust for biases in features forecast by the model.
Characteristics of Reprocessed Hydrometeorological Automated Data System (HADS) Hourly Precipitation Data
Authors: Kim Dongsoo , Nelson Brian , Seo Dong-Jun 
Published: May 2009

Abstract
The Hydrometeorological Automated Data System (HADS) is a real-time data acquisition, processing, and distribution system operated by the Office of Hydrologic Development (OHD) of NOAA’s National Weather Service (NWS). The initial reprocessing of HADS data from its original format since its inception in July 1996 has been completed at NOAA’s National Climatic Data Center (NCDC). The quality of the reprocessed HADS hourly precipitation data from rain gauges is assessed by two objective metrics: the average fraction of missing values and the percentage of top-of-the-hour observations for a 3-yr period (2003–05). Pairwise comparisons between the reprocessed product and the real-time product are made using representative samples (about 13%) from the 48 contiguous United States. The monthly average of missing values varies from 0.5% to 2% in the reprocessed product and from 1.7% to 10.1% in the real-time product. Except for January 2003, the reprocessed product consistently reduced missing values, by as much as 9.4% in October 2004. The availability of top-of-the-hour observations is about 85% in the reprocessed product, while the real-time product has top-of-the-hour observations only about 50% of the time. This paper discusses real-time product quality issues, additional quality assurance algorithms used in the reprocessing environment, and the design of system-wide performance comparisons. Thus, the benefits to users of reprocessing the HADS data are the correction of 4-h observation time errors during 1 July–11 August 2005 and the demonstration of diurnals pattern of precipitation frequencies in regional domains. A Web-based interactive quality assessment tool for reprocessed HADS hourly precipitation data and access to the data are also presented.
Symptoms and problems in a nationally representative sample of advanced cancer patients
Authors: Johnsen AT , Petersen MA , Pedersen L , Groenvold M 
Published: May 2009

Little is known about the need for palliative care among advanced cancer patients who are not in specialist palliative care. The purpose was to identify prevalence and predictors of symptoms and problems in a nationally representative sample of Danish advanced cancer patients. Patients with cancer stage 3 or 4 from 54 hospital departments ( n = 1630) received the EORTC QLQ-C30 questionnaire. Mean scores were calculated according to the scoring manual and in addition a ‘symptom/problem’ and a ‘severe symptom/problem’ was defined and calculated. Multiple logistic regression was used to identify predictors. In total, 977 (60%) patients participated. The most frequent symptoms/problems were fatigue (57%; severe 22%) followed by reduced role function, insomnia and pain. Age, cancer stage, primary tumour, type of department, marital status and whether the patient had recently been hospitalized or not were associated with several symptoms and problems. This is probably the first nationally representative study of its kind. It shows that advanced cancer patients in Denmark have symptoms and problems that deserve attention and that some patient groups are especially at risk.
Swimming pool attendance and risk of asthma and allergic symptoms in children
Authors: Font-Ribera L. , Kogevinas M. , Zock J-P. , Nieuwenhuijsen M. J. , Heederik D. , Villanueva C. M. 
Published: May 2009

Increased asthma risk has been associated with pool attendance in children but evidence is inconsistent and inconclusive. A survey was conducted of 3,223 9–12-yr-old children in Sabadell (Spain) to evaluate association between swimming pool attendance and prevalence of asthma and allergic conditions and symptoms.Parents completed a questionnaire on lifetime frequency of pool attendance and symptoms in the last 12 months (wheezing, asthma medication, rhinitis and allergic rhinitis), ever having asthma and eczema, and potential confounders. Indicators of indoor and outdoor swimming pool attendance early in life, cumulatively and currently were calculated.Swimming pool attendance before the age of 2 yrs was associated with slightly lower prevalence of current asthma (OR 0.79, 95% CI 0.43–1.46), rhinitis (OR 0.86, 95% CI 0.68–1.08) and allergic rhinitis symptoms (OR 0.72, 95% CI 0.54–0.96) compared to those who started attending swimming pools after 4 yrs of age. An increased prevalence of eczema was associated with duration of lifetime pool attendance (OR 1.71, 95%CI 1.38–2.12 for >5 yrsversus0 yrs).Swimming pool attendance in Spanish children was associated with slightly less upper and lower respiratory tract symptoms and with more eczema. Longitudinal studies are required to confirm these findings and avoid potential reverse causation.
Pneumonia risk in COPD patients receiving inhaled corticosteroids alone or in combination: TORCH study results
Authors: Crim C. , Calverley P. M. A. , Anderson J. A. , Celli B. , Ferguson G. T. , Jenkins C. , Jones P. W. , Willits L. R. , Yates J. C. , Vestbo J. 
Published: May 2009

Inhaled corticosteroids (ICS) are important in reducing exacerbation frequency associated with chronic obstructive pulmonary disease (COPD). However, little is known about the risk of associated infections.In apost hocanalysis of the TOwards a Revolution in COPD Health (TORCH) study, we analysed and identified potential risk factors for adverse event reports of pneumonia in this randomised, double-blind trial comparing twice-daily inhaled salmeterol (SAL) 50 μg, fluticasone propionate (FP) 500 μg, and the combination (SFC) with placebo in 6,184 patients with moderate-to-severe COPD over 3 yrs.Despite a higher withdrawal rate in the placebo arm, after adjusting for time on treatment, a greater rate of pneumonia was reported in the FP and SFC treatment arms (84 and 88 per 1,000 treatment-yrs, respectively) compared with SAL and placebo (52 and 52 per 1,000 treatment-yrs, respectively). Risk factors for pneumonia were age ≥55 yrs, forced expiratory volume in 1 s <50% predicted, COPD exacerbations in the year prior to the study, worse Medical Research Council dyspnoea scores and body mass index <25 kg·m−2. No increase in pneumonia deaths with SFC was observed; this could not be concluded for FP.Despite the benefits of ICS-containing regimens in COPD management, healthcare providers should remain vigilant regarding the possible development of pneumonia as a complication in COPD patients receiving such therapies.
Role of the tachykinin NK1 receptor in a murine model of cigarette smoke-induced pulmonary inflammation
Authors: De Swert Katelijne O , Bracke Ken R , Demoor Tine , Brusselle Guy G , Joos Guy F 
Published: May 2009

AbstractBackgroundThe tachykinins, substance P and neurokinin A, present in sensory nerves and inflammatory cells such as macrophages and dendritic cells, are considered as pro-inflammatory agents. Inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and increased tachykinin levels are recovered from the airways of COPD patients. The aim of our study was to clarify the involvement of the tachykinin NK1receptor, the preferential receptor for substance P, in cigarette smoke (CS)-induced pulmonary inflammation and emphysema in a mouse model of COPD.MethodsTachykinin NK1receptor knockout (NK1-R-/-) mice and their wild type controls (all in a mixed 129/sv-C57BL/6 background) were subjected to sub acute (4 weeks) or chronic (24 weeks) exposure to air or CS. 24 hours after the last exposure, pulmonary inflammation and development of emphysema were evaluated.ResultsSub acute and chronic exposure to CS resulted in a substantial accumulation of inflammatory cells in the airways of both WT and NK1-R-/-mice. However, the CS-induced increase in macrophages and dendritic cells was significantly impaired in NK1-R-/-mice, compared to WT controls, and correlated with an attenuated release of MIP-3α/CCL20 and TGF-β1. Chronic exposure to CS resulted in development of pulmonary emphysema in WT mice. NK1-R-/-mice showed already enlarged airspaces upon air-exposure. Upon CS-exposure, the NK1-R-/-mice did not develop additional destruction of the lung parenchyma. Moreover, an impaired production of MMP-12 by alveolar macrophages upon CS-exposure was observed in these KO mice. In a pharmacological validation experiment using the NK1receptor antagonist RP 67580, we confirmed the protective effect of absence of the NK1receptor on CS-induced pulmonary inflammation.ConclusionThese data suggest that the tachykinin NK1receptor is involved in the accumulation of macrophages and dendritic cells in the airways upon CS-exposure and in the development of smoking-induced emphysema. As both inflammation of the airways and parenchymal destruction are important characteristics of COPD, these findings may have implications in the future treatment of this devastating disease.
siRNA-based targeting of antiapoptotic genes can reverse chemoresistance in P-glycoprotein expressing chondrosarcoma cells
Authors: Kim Dae Won , Kim Kyung-Ok , Shin Mike J , Ha Jung Hee , Seo Sung Wook , Yang Jay , Lee Francis Y 
Published: May 2009

AbstractBackgroundHigh expression of P-glycoprotein is one of the well-known mechanisms of chemoresistance in chondrosarcomas. However, the role of antiapoptotic proteins, a common mechanism responsible for chemoresistance in other tumors, has not been well studied in chondrosarcomas. We examined the importance of P-glycoprotein and antiapoptotic proteins in the chemoresistance to doxorubicin of two Grade II chondrosarcoma cell lines, JJ012 and SW1353.ResultsWe confirmed that both chondrosarcoma cell types expressed P-glycoprotein and antiapoptotic proteins (Bcl-2, Bcl-xL and XIAP). siRNA knockdown as well as pharmacologic inhibitors of cell survival proteins (Bcl-2, Bcl-xL and XIAP) enhanced apoptosis of chemoresistant chondrosarcoma cells by up to 5.5 fold at 0.1 μmol and 5.5 fold at 1 μmol doxorubicin. These chemosensitizing effects were comparable to those of P-glycoprotein inhibition by siRNA or pharmacologic inhibitor.ConclusionThese findings suggest that antiapoptotic proteins play a significant role in the chemoresistance of chondrosarcoma cells independent of P-glycoprotein. Based on the results, a new siRNA-based therapeutic strategy targeting antiapoptotic genes can be designed to overcome the chemoresistance of chondrosarcomas which is often conferred by P-glycoprotein.
Two-stimuli manipulation of a biological motor
Authors: Ristic Zorica , Vitali Marco , Duci Alessandro , Goetze Christian , Kemnitz Klaus , Zuschratter Werner , Lill Holger , Bald Dirk 
Published: May 2009

AbstractF1-ATPase is an enzyme acting as a rotary nano-motor. During catalysis subunits of this enzyme complex rotate relative to other parts of the enzyme. Here we demonstrate that the combination of two input stimuli causes stop of motor rotation. Application of either individual stimulus did not significantly influence motor motion. These findings may contribute to the development of logic gates using single biological motor molecules.