bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlled Exposure of Healthy Young Volunteers to Ozone Causes Cardiovascular Effects
Authors: Devlin Robert B. , Duncan Kelly E. , Jardim Melanie , Schmitt Michael T. , Rappold Ana G. , Diaz-Sanchez David 
Published: June 2012

Background—
Recent epidemiology studies have reported associations between short-term ozone exposure and mortality. Such studies have previously reported associations between airborne particulate matter pollution and mortality, and support for a causal relationship has come from controlled-exposure studies that describe pathophysiological mechanisms by which particulate matter could induce acute mortality. In contrast, for ozone, almost no controlled-human-exposure studies have tested whether ozone exposure can modulate the cardiovascular system.

Methods and Results—
Twenty-three young healthy individuals were exposed in a randomized crossover fashion to clean air and to 0.3-ppm ozone for 2 hours while intermittently exercising. Blood was obtained immediately before exposure, immediately afterward, and the next morning. Continuous Holter monitoring began immediately before exposure and continued for 24 hours. Lung function was performed immediately before and immediately after exposure, and bronchoalveolar lavage was performed 24 hours after exposure. Immediately after ozone exposure, we observed a 98.9% increase in interleukin-8, a 21.4% decrease in plasminogen activator inhibitor-1, a 51.3% decrease in the high-frequency component of heart rate variability, and a 1.2% increase in QT duration. Changes in interleukin-1B and plasminogen activator inhibitor-1 were apparent 24 hours after exposure. In agreement with previous studies, we also observed ozone-induced drops in lung function and an increase in pulmonary inflammation.

Conclusions—
This controlled-human-exposure study shows that ozone can cause an increase in vascular markers of inflammation and changes in markers of fibrinolysis and markers that affect autonomic control of heart rate and repolarization. We believe that these findings provide biological plausibility for the epidemiology studies that associate ozone exposure with mortality.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT01492517.
Cavitation After Acute Symptomatic Lacunar Stroke Depends on Time, Location, and MRI Sequence
Authors: Moreau Francois , Patel Shiel , Lauzon M. Louis , McCreary Cheryl R. , Goyal Mayank , Frayne Richard , Demchuk Andrew M. , Coutts Shelagh B. , Smith Eric E. 
Published: June 2012

Background and Purpose—
Definitions for chronic lacunar infarcts vary. Recent retrospective studies suggest that many acute lacunar strokes do not develop a cavitated appearance. We determined the characteristics of acute lacunar infarcts on follow-up MRI in consecutive patients participating in prospective research studies.

Methods—
Patients with acute lacunar infarction on diffusion-weighted imaging were selected from 3 prospective cohort studies of minor stroke imaged within <24 hours of onset. Follow-up MRI was performed at 30 days (Vascular Imaging of Acute Stroke for Identifying Predictors of Clinical Outcome and Recurrent Ischemic Events [VISION] study, n=21) or 90 days (VISION-2 and CT and MRI in the Triage of TIA and Minor Cerebrovascular Events to Identify High Risk Patients [CATCH] studies, n=34). Evidence of cavitation on MRI was rated separately on fluid-attenuated inversion recovery, T1, and T2 sequences by 2 independent study physicians; discrepant readings were resolved by consensus.

Results—

Probable or definite cavitation on any sequence was more common at 90 days compared with 30 days (
P
≤0.001 for all sequences). At 90 days, evidence of cavitation was seen on at least 1 sequence in 33 of 34 patients (97%). The T1-weighted sequence was most sensitive to the presence of cavitation (94% at 90 days). By contrast, the fluid-attenuated inversion recovery sequence frequently failed to show evidence of cavitation in the brain stem or thalamus (only 10 of 18 [56%] showed cavitation).

Conclusions—
MRI scanning at 90 days with T1-weighted imaging reveals evidence of cavitation in nearly all cases of acute lacunar infarction. By contrast, reliance on fluid-attenuated inversion recovery alone will miss many cavitated lesions in the thalamus and brain stem. These factors should be taken into account in the development of standardized criteria for lacunar infarction on MRI.
Using Random Effects to Build Impact Models When the Available Historical Record Is Short
Authors: Aires Filipe 
Published: June 2012

AbstractThe analysis of the affect of weather and climate on human activities requires the construction of impact models that are able to describe the complex links between weather and socioeconomic data. In practice, one of the biggest challenges is the lack of data, because it is generally difficult to obtain time series that are long enough. As a consequence, derived impact models predict well the historical record but are unable to perform well on real forecasts. To avoid this data-limitation problem, it is possible to train the impact model over a large spatial domain by “pooling” data from multiple locations. This general impact model needs to be spatially corrected to take local conditions into account, however. This is particularly true, for example, in agriculture: it is not efficient to pool all of the spatial data into a single very general impact model, but it is also not efficient to develop one impact model for each spatial location. To solve these aggregation problems, mixed-effects (ME) models have been developed. They are based on the idea that each datum belongs to a particular group, and the ME model takes into account the particularities of each group. In this paper, ME models and, in particular, random-effects (RE) models are tested and are compared with more-traditional methods using a real-world application: the sales of salt for winter road deicing by public service vehicles. It is shown that the performance of RE models is higher than that of more-traditional regression models. The development of impact models should strongly benefit from the use of RE and ME models.
Trends in Wind Speed at Wind Turbine Height of 80 m over the Contiguous United States Using the North American Regional Reanalysis (NARR)
Authors: Holt Eric , Wang Jun 
Published: June 2012

AbstractThe trends in wind speed at a typical wind turbine hub height (80 m) are analyzed using the North American Regional Reanalysis (NARR) dataset for 1979–2009. A method, assuming the wind profile in the lower boundary layer as power-law functions of altitude, is developed to invert the power exponent (in the power-law equation) from the NARR data and to compute the following variables at 80 m that are needed for the estimation and interpretation of the trend in wind speed: air density, zonal wind u, meridional wind υ, and wind speed. Statistically significant and positive annual trends are found to be predominant over the contiguous United States, with spring and winter being the two largest contributing seasons. Positive trends in surface wind speed are generally smaller than those at 80 m, with less spatial coverage, reflecting stronger increases in wind speed at altitudes above the 80-m level. Large and positive trends in winds over the southeastern region and high-mountain region are primarily due to the increasing trend in southerly wind, while the trends over the northern states (near the Canadian border) are primarily due to the increasing trend in westerly wind. Trends in the 90th percentile of the annual wind speed, a better indicator for the trend in wind power recourses, are 40%–50% larger than but geographically similar to the trends in the annual mean wind speed. The probable climatic drivers for change in wind speed and direction are discussed, and further studies are needed to evaluate the fidelity of wind speed and direction in the NARR.
Determining the Flight Icing Threat to Aircraft with Single-Layer Cloud Parameters Derived from Operational Satellite Data
Authors: Smith William L. , Minnis Patrick , Fleeger Cecilia , Spangenberg Douglas , Palikonda Rabindra , Nguyen Louis 
Published: June 2012

AbstractAn algorithm is developed to determine the flight icing threat to aircraft utilizing quantitative information on clouds derived from meteorological satellite data as input. Algorithm inputs include the satellite-derived cloud-top temperature, thermodynamic phase, water path, and effective droplet size. The icing-top and -base altitude boundaries are estimated from the satellite-derived cloud-top and -base altitudes using the freezing level obtained from numerical weather analyses or a lapse-rate approach. The product is available at the nominal resolution of the satellite pixel. Aircraft pilot reports (PIREPs) over the United States and southern Canada provide direct observations of icing and are used extensively in the algorithm development and validation on the basis of correlations with Geostationary Operational Environmental Satellite imager data. Verification studies using PIREPs, Tropospheric Airborne Meteorological Data Reporting, and NASA Icing Remote Sensing System data indicate that the satellite algorithm performs reasonably well, particularly during the daytime. The algorithm is currently being run routinely using data taken from a variety of satellites across the globe and is providing useful information on icing conditions at high spatial and temporal resolutions that are unavailable from any other source.
Application of Lidar Data to Assist Airmass Discrimination at the Whistler Mountaintop Observatory
Authors: Gallagher John P. , McKendry Ian G. , Cottle Paul W. , Macdonald Anne Marie , Leaitch W. Richard , Strawbridge Kevin 
Published: June 2012

AbstractA ground-based lidar system that has been deployed in Whistler, British Columbia, Canada, since the spring of 2010 provides a means of evaluating vertical aerosol structure in a mountainous environment. This information is used to help to determine when an air chemistry observatory atop Whistler Mountain (2182 m MSL) is within the free troposphere or is influenced by the valley-based planetary boundary layer (PBL). Three case studies are presented in which 1-day time series images of backscatter data from the lidar are analyzed along with concurrent meteorological and air-chemistry datasets from the mountaintop site. The cases were selected to illustrate different scenarios of diurnal PBL evolution that are expected to be common during their respective seasons. The lidar images corroborate assumptions about PBL influence as derived from analysis of diurnal trends in water vapor, condensation nuclei, and ozone. Use of all of these datasets together bolsters efforts to determine which atmospheric layer the site best represents, which is important when evaluating the provenance of air samples.
Vertical Velocity and Microphysical Distributions Related to Rapid Intensification in a Simulation of Hurricane Dennis (2005)
Authors: McFarquhar Greg M. , Jewett Brian F. , Gilmore Matthew S. , Nesbitt Stephen W. , Hsieh Tsung-Lin 
Published: June 2012

Abstract
A 1-km Weather Research and Forecasting model simulation of Hurricane Dennis was used to identify precursors in vertical velocity and latent heating distributions to rapid intensification (RI). Although the observed structure qualitatively replicated data obtained during P-3 and Earth Resources-2 (ER-2) flights, the simulated reflectivity was overestimated. During the 6 h preceding RI, defined as 0000 UTC 8 July 2005 close to the time of simulated maximum central pressure deepening, the asymmetric convection transformed into an eyewall with the maximum 10-m wind speed increasing by 16 m s−1.
Contour by frequency altitude diagrams showed unique changes in the breadth of simulated vertical velocity (w) distributions before and after RI. Outliers of w distributions at 14 km preceded RI onset, whereas the increase in w outliers at 6 km lagged it. Prior to RI there was an increase in the upward flux of hydrometeors between 10 and 15 km, with increased contributions from w &gt; 6 m s−1. Increases in lower-level updraft airmass fluxes did not lead RI, but the 14-km positive w outliers were better indicators of RI onset than positive w averages. The area of convective bursts did not strongly increase before RI, but it continually increased after RI. Latent heating was dominated by contributions from w &lt; 2 m s−1, meaning increases in positive w outliers before RI did not cause the increase in latent heating seen during RI. The location of convective bursts and outliers of positive and negative w distributions contracted toward the eye as the simulated Dennis intensified.
Effect of Aerosol on Cloud–Environment Interactions in Trade Cumulus
Authors: Lee Seoung-Soo , Feingold Graham , Chuang Patrick Y. 
Published: June 2012

Abstract
This study examines the role of aerosol in mediating interactions between a warm trade cumulus cloud system and the environment that spawns it. Numerical simulations of the observed and well-studied Rain in Cumulus over the Ocean (RICO) field experiment are performed. The results draw on simulations of 34-h duration so as to avoid conclusions based on transients. Simulations show that, on average, aerosol-perturbed clouds are initially deeper and more vigorous but that after about 14 h there is a reversal in this trend, and unperturbed clouds deepen relative to the perturbed clouds. Differences in cloud depth are about 100 m, and differences in vertical velocity variance are about 30%. After about 20 h, most cloud fields are statistically similar with the exception of rain rate and optical depth, which are lower and higher, respectively, in the high-aerosol conditions. By sampling the model output at various points in the cloud system evolution, the mechanisms responsible for the initial differences and then convergence of most of the cloud field properties are addressed. Sensitivity tests indicate that responses are driven primarily by temperature profiles, rather than by humidity profiles, and that the general trend to homogenization of the bulk cloud field properties is robust for different forcings. Finally, the paper shows that even transient aerosol perturbations may endure beyond the duration of the perturbation itself, provided they persist long enough. Short-duration aerosol perturbations are unlikely to have much influence on the system.
Greenland Freshwater Runoff. Part II: Distribution and Trends, 1960–2010
Authors: Mernild Sebastian H. , Liston Glen E. 
Published: June 2012

Abstract
Runoff magnitudes, the spatial patterns from individual Greenland catchments, and their changes through time (1960–2010) were simulated in an effort to understand runoff variations to adjacent seas and to illustrate the capability of SnowModel (a snow and ice evolution model) and HydroFlow (a runoff routing model) to link variations in terrestrial runoff with ocean processes and other components of Earth’s climate system. Significant increases in air temperature, net precipitation, and local surface runoff lead to enhanced and statistically significant Greenland ice sheet (GrIS) surface mass balance (SMB) loss. Total Greenland runoff to the surrounding oceans increased 30%, averaging 481 ± 85 km3 yr−1. Averaged over the period, 69% of the runoff to the surrounding seas originated from the GrIS and 31% came from outside the GrIS from rain and melting glaciers and ice caps. The runoff increase from the GrIS was due to an 87% increase in melt extent, 18% from increases in melt duration, and a 5% decrease in melt rates (87% + 18% − 5% = 100%). In contrast, the runoff increase from the land area surrounding the GrIS was due to a 0% change in melt extent, a 108% increase in melt duration, and an 8% decrease in melt rate. In general, years with positive Atlantic multidecadal oscillation (AMO) index equaled years with relatively high Greenland runoff volume and vice versa. Regionally, runoff was greater from western than eastern Greenland. Since 1960, the data showed pronounced runoff increases in west Greenland, with the greatest increase occurring in the southwest and the lowest increase in the northwest.
Investigating Global Tropical Cyclone Activity with a Hierarchy of AGCMs: The Role of Model Resolution
Authors: Strachan Jane , Vidale Pier Luigi , Hodges Kevin , Roberts Malcolm , Demory Marie-Estelle 
Published: June 2012

Abstract
The ability to run general circulation models (GCMs) at ever-higher horizontal resolutions has meant that tropical cyclone simulations are increasingly credible. A hierarchy of atmosphere-only GCMs, based on the Hadley Centre Global Environmental Model version 1 (HadGEM1) with horizontal resolution increasing from approximately 270 to 60 km at 50°N, is used to systematically investigate the impact of spatial resolution on the simulation of global tropical cyclone activity, independent of model formulation. Tropical cyclones are extracted from ensemble simulations and reanalyses of comparable resolutions using a feature-tracking algorithm. Resolution is critical for simulating storm intensity and convergence to observed storm intensities is not achieved with the model hierarchy. Resolution is less critical for simulating the annual number of tropical cyclones and their geographical distribution, which are well captured at resolutions of 135 km or higher, particularly for Northern Hemisphere basins. Simulating the interannual variability of storm occurrence requires resolutions of 100 km or higher; however, the level of skill is basin dependent. Higher resolution GCMs are increasingly able to capture the interannual variability of the large-scale environmental conditions that contribute to tropical cyclogenesis. Different environmental factors contribute to the interannual variability of tropical cyclones in the different basins: in the North Atlantic basin the vertical wind shear, potential intensity, and low-level absolute vorticity are dominant, whereas in the North Pacific basins midlevel relative humidity and low-level absolute vorticity are dominant. Model resolution is crucial for a realistic simulation of tropical cyclone behavior, and high-resolution GCMs are found to be valuable tools for investigating the global location and frequency of tropical cyclones.
Regional Perspective on Mechanisms for Tropical Precipitation Frequency and Intensity under Global Warming
Authors: Chen Chao-An , Chou Chia , Chen Cheng-Ta 
Published: June 2012

Abstract
From a global point of view, a shift toward more intense precipitation is often found in observations and global warming simulations. However, similar to changes in mean precipitation, these changes associated with precipitation characters, such as intensity and frequency, should vary with space. Based on the classification of the subregions for the tropics in Chou et al., changes in precipitation frequency and intensity and their association with changes in mean precipitation are analyzed on a regional basis in 10 coupled global climate models. Furthermore, mechanisms for these changes are also examined, via the thermodynamic and dynamic contributions.
In general, the increase (decrease) of mean precipitation is mainly attributed to increases (decreases) in the frequency and intensity of almost all strengths of precipitation: that is, light to heavy precipitation. The thermodynamic contribution, which is associated with increased water vapor, is positive to both precipitation frequency and intensity, particularly for precipitation extremes, and varies little with space. On the other hand, the dynamic contribution, which is related to changes in the tropical circulation, is the main process for inducing the spatial variation of changes in precipitation frequency and intensity. Among mechanisms that induce the dynamic contribution, the rich-get-richer mechanism (the dynamic part), ocean feedback, and warm horizontal advection increase precipitation frequency and intensity, while the upped-ante mechanism, the deepening of convection, longwave radiation cooling, and cold horizontal advection tend to reduce precipitation frequency and intensity.
Coherent Synoptic Disturbances in the Australian Monsoon
Authors: Berry Gareth J. , Reeder Michael J. , Jakob Christian 
Published: June 2012

Abstract
Coherent synoptic-scale weather systems within the Australian monsoon are identified and tracked in the isentropic potential vorticity (PV) field from the ECMWF Interim Reanalysis (ERA-Interim) dataset during the Southern Hemisphere summer. The resulting dataset is then used to compile statistics and synoptic composites of Australian monsoon disturbances. On average, a synoptic system is found in the region every 2.5 days. However, the time interval between consecutive events is highly variable, meaning that the synoptic activity in the Australian monsoon is not well represented by commonly employed spectral techniques. The analysis reveals that most synoptic systems originate within the Australian monsoon, but at the 315-K level (approximately 700 hPa) a significant proportion of systems are first detected near the east coast of the continent where extratropical Rossby waves are observed to frequently break.
The average Australian monsoon weather system propagates from east to west at approximately 6 m s−1 and has a characteristic length scale of 2000 km. Synoptic composite structures show some resemblance to African easterly waves; they move along a midtropospheric (approximately 700 hPa) easterly wind maximum and have peak meridional winds at this level. Composite rainfall shows that rainfall is significantly enhanced ahead (west) of the synoptic PV maximum and suppressed behind. It is estimated that in some parts of northwestern Australia 40%–50% of the summertime rainfall occurs with a tracked monsoon disturbance in the vicinity.
Changes in eating attitudes, eating disorders and body weight in Chinese medical university students
Authors: Liao Yanhui , Liu Tieqiao , Cheng Yao , Wang Jichuan , Deng Yunlong , Hao Wei , Chen Xiaogang , Xu Yahui , Wang Xiuyan , Tang Jinsong 
Published: June 2012

Background: Eating disorders is a particular problem for university students. However, little is known about this problem among medical students who often have high stress. Aims: The aims of this study were to describe the changes in eating attitudes and eating disorders from 2006 to 2008 in a medical student sample, and to compare the gender differences of eating attitudes and body mass index (BMI, kg/m2) with this sample. Methods: This study was conducted in Changsha city, Mainland China. Self-reported questionnaires, including the Eating Attitudes Test (EAT) and Eating Disorders Assessment Questionnaire (CETCA), were employed to examine the changes in eating attitudes and eating disorders from 2006 to 2008 in a medical student sample (N = 500). Results: Self-reported findings suggest that tentative eating disorders prevalence was 0.90% (anorexia nervosa (AN): 0; bulimia nervosa (BN): 4 females) in 2006 and 1.44% (AN: 1 male; BN: 1 male and 3 females) in 2008 of the full sample. The present data showed that 2.26% (2 males and 9 females) in 2006 and 2.47% (4 males and 6 females) in 2008 of all students obtained scores greater than 20 on the EAT-26 indicative of distorted eating attitudes and behaviour. Male students kept lower distorted eating attitudes and behaviours than female students, while female students kept a lower BMI than male students in both 2006 and 2008. However, there were no statistically significant changes in eating attitudes, distorted eating attitudes and CETCA in either male or female students from 2006 to 2008. Conclusions: The results of this study suggest that there were no statistically significant changes from 2006 to 2008 in eating attitudes, distorted eating attitudes and CETCA. However, females showed significantly higher eating disorders and distorted eating attitudes compared to males in both 2006 and 2008. This study is furthering our understanding of eating disorders in a Chinese cultural context.