bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Genome-Wide Association and Mouse Knockout Approaches Identify Platelet Supervillin as an Inhibitor of Thrombus Formation Under Shear Stress
Authors: Edelstein Leonard C. , Luna Elizabeth J. , Gibson Ian B. , Bray Molly , Jin Ying , Kondkar Altaf , Nagalla Srikanth , Hadjout-Rabi Nacima , Smith Tara C. , Covarrubias Daniel , Jones Stephen N. , Ahmad Firdos , Stolla Moritz , Kong Xianguo , Fang Zhiyou , Bergmeier Wolfgang , Shaw Chad , Leal Suzanne M. , Bray Paul F. 
Published: May 2012

Background—
High shear force critically regulates platelet adhesion and thrombus formation during ischemic vascular events. To identify genetic factors that influence platelet thrombus formation under high shear stress, we performed a genome-wide association study and confirmatory experiments in human and animal platelets.

Methods and Results—

Closure times in the shear-dependent platelet function analyzer (PFA)–100 were measured on healthy, nondiabetic European Americans (n=125) and blacks (n=116). A genome-wide association (
P
<5×10
−8
) was identified with 2 single-nucleotide polymorphisms within the
SVIL
gene (chromosome 10p11.23) in African Americans but not European Americans. Microarray analyses of human platelet RNA demonstrated the presence of
SVIL
isoform 1 (supervillin) but not muscle-specific isoforms 2 and 3 (archvillin, SmAV).
SVIL
mRNA levels were associated with
SVIL
genotypes (
P
≤0.02) and were inversely correlated with PFA-100 closure times (
P
<0.04) and platelet volume (
P
<0.02). Leukocyte-depleted platelets contained abundant levels of the ≈205-kDa supervillin polypeptide. To assess functionality, mice lacking platelet supervillin were generated and back-crossed onto a C57BL/6 background. Compared with controls, murine platelets lacking supervillin were larger by flow cytometry and confocal microscopy and exhibited enhanced platelet thrombus formation under high-shear but not low-shear conditions.

Conclusions—

We show for the first time that (1) platelets contain supervillin; (2) platelet thrombus formation in the PFA-100 is associated with human
SVIL
variants and low
SVIL
expression; and (3) murine platelets lacking supervillin exhibit enhanced platelet thrombus formation at high shear stress. These data are consistent with an inhibitory role for supervillin in platelet adhesion and arterial thrombosis.
Carotid Endarterectomy in Asymptomatic Patients With Limited Life Expectancy
Authors: Wallaert Jessica B. , De Martino Randall R. , Finlayson Samuel R.G. , Walsh Daniel B. , Corriere Matthew A. , Stone David H. , Cronenwett Jack L. , Goodney Philip P. 
Published: May 2012

Background and Purpose
Data from randomized trials assert that asymptomatic patients undergoing carotid endarterectomy (CEA) must live 3 to 5 years to realize the benefit of surgery. We examined how commonly CEA is performed among asymptomatic patients with limited life expectancy.

Methods
Within the American College of Surgeons National Quality Improvement Project we identified 8 conditions associated with limited life expectancy based on survival estimates using external sources. We then compared rates of 30-day stroke, death, and myocardial infarction after CEA between asymptomatic patients with and without life-limiting conditions.

Results

Of 12 631 CEAs performed in asymptomatic patients, 2525 (20.0%) were in patients with life-limiting conditions or diagnoses. The most common conditions were severe chronic obstructive pulmonary disease and American Society of Anesthesiologists Class IV designation. Patients with life-limiting conditions had significantly higher rates of perioperative complications, including stroke (1.8% versus 0.9%,
P
<0.001), death (1.4% versus 0.3%,
P
<0.001), and stroke/death (2.9% versus 1.1%,
P
<0.001). Even after adjustment for other comorbidities, patients with life-limiting conditions were nearly 3 times more likely to experience perioperative stroke or death than those without these conditions (OR, 2.8; 95% CI, 2.1–3.8;
P
<0.001).

Conclusion
CEA is performed commonly in asymptomatic patients with life-limiting conditions. Given the high rates of postoperative stroke/death in these patients as well as their limited life expectancy, the net benefit of CEA in this population remains uncertain. Health policy research examining the role of CEA in asymptomatic patients with life-limiting conditions is necessary and may serve as a potential source for significant healthcare savings in the future.
The Course of Unilateral Intracranial Arteriopathy in Young Adults With Arterial Ischemic Stroke
Authors: Bulder Marcel M.M. , Braun Kees P.J. , Leeuwis Jan Willem , Lo Rob T.H. , van Nieuwenhuizen Onno , Kappelle L. Jaap , Klijn Catharina J.M. 
Published: May 2012

Background and Purpose—
Unilateral intracranial focal nonprogressive arteriopathy is often found in children with arterial ischemic stroke. We aimed to investigate the course of unilateral intracranial arteriopathy in young adults.

Methods—
We searched the Utrecht Stroke Database for patients between 16 and 50 years of age diagnosed with anterior circulation arterial ischemic stroke and a nonatherosclerotic, unilateral intracranial large-artery arteriopathy between 1991 and 2005. We assessed clinical features, potential causes, risk factors, extent of infarction and arteriopathy at presentation, long-term angiographic course, and clinical outcome.

Results—
Of 356 patients with anterior circulation arterial ischemic stroke, 17 (5%) had a documented unilateral intracranial arteriopathy, of whom 14 could be included for follow-up investigations (median age, 34 years; range, 27–49 years). Median duration of follow-up was 8.8 years (range, 1.7–12.8 years). In 11 patients, onset of symptoms was not abrupt. The arteriopathy normalized completely in 5 and improved in 3 patients; in none of the patients did the arteriopathy worsen. Two of 14 patients had recurrent symptoms. Ten patients (71%) had a good outcome (modified Rankin Scale score ≤2).

Conclusions—
In young adults, arterial ischemic stroke is rarely caused by a unilateral intracranial arteriopathy. Similar to children, onset of symptoms in young adults is often not abrupt and the arteriopathy may improve over time. Late recurrences were rare. Possibly, a monophasic inflammatory process, as has been suggested for childhood intracranial focal nonprogressive arteriopathies, also occurs in young adults.
The Radiation Budget of the West African Sahel and Its Controls: A Perspective from Observations and Global Climate Models
Authors: Miller Mark A. , Ghate Virendra P. , Zahn Robert K. 
Published: May 2012

Abstract
Continuous measurements of the shortwave (SW), longwave (LW), and net cross-atmosphere radiation flux divergence over the West African Sahel were made during the year 2006 using the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) and the Geostationary Earth Radiation Budget (GERB) satellite. Accompanying AMF measurements enabled calculations of the LW, SW, and net top of the atmosphere (TOA) and surface cloud radiative forcing (CRF), which quantifies the radiative effects of cloud cover on the column boundaries. Calculations of the LW, SW, and net cloud radiative effect (CRE), which is the difference between the TOA and surface radiative flux divergences in all-sky and clear-sky conditions, quantify the radiative effects on the column itself. These measurements were compared to predictions in four global climate models (GCMs) used in the Intergovernmental Panel for Climate Change Fourth Assessment Report (IPCC AR4). All four GCMs produced wet and dry seasons, but reproducing the SW column radiative flux divergence was problematic in the GCMs and SW discrepancies translated into discrepancies in the net radiative flux divergence. Computing cloud-related quantities from the measurements produced yearly averages of the SW TOA CRF, surface CRF, and CRE of ~−19, −83, and 47 W m−2, respectively, and yearly averages of the LW TOA CRF, surface CRF, and CRE of ~39, 37, and 2 W m−2. These quantities were analyzed in two GCMs and compensating errors in the SW and LW clear-sky, cross-atmosphere radiative flux divergence were found to conspire to produce somewhat reasonable predictions of the net clear-sky divergence. Both GCMs underestimated the surface LW and SW CRF and predicted near-zero SW CRE when the measured values were substantially larger (~70 W m−2 maximum).
A Climatology of Subtropical Cyclones in the South Atlantic
Authors: Evans Jenni L. , Braun Aviva 
Published: May 2012

A 50-yr climatology (1957–2007) of subtropical cyclones (STs) in the South Atlantic is developed and analyzed. A subtropical cyclone is a hybrid structure (upper-level cold core and lower-level warm core) with associated surface gale-force winds. The tendency for warm season development of North Atlantic STs has resulted in these systems being confused as tropical cyclones (TCs). In fact, North Atlantic STs are a regular source of the incipient vortices leading to North Atlantic TC genesis. In 2004, Hurricane Catarina developed in the South Atlantic and made landfall in Brazil. A TC system had been previously unobserved in the South Atlantic, so the incidence of Catarina highlighted the lack of an ST climatology for the region to provide a context for the likelihood of future systems. Sixty-three South Atlantic STs are documented over the 50-yr period analyzed in this climatology. In contrast to the North Atlantic, South Atlantic STs occur relatively uniformly throughout the year; however, their preferred location of genesis and mechanisms for this genesis do exhibit some seasonal variability. Rossby wave breaking was identified as the mechanism for the ST vortex initiation for North Atlantic STs. A subset of South Atlantic STs forms via this mechanism, however, an additional mechanism for ST genesis is identified here: lee cyclogenesis downstream of the Andes in the Brazil Current region—an area favorable for convection. This formation mechanism is similar to development of type-2 east coast lows in the Tasman Sea off eastern Australia.
The Influence of Boundary Layer Processes on the Diurnal Variation of the Climatological Near-Surface Wind Speed Probability Distribution over Land*
Authors: He Yanping , McFarlane Norman A. , Monahan Adam H. 
Published: May 2012

Abstract
Knowledge of the diurnally varying land surface wind speed probability distribution is essential for surface flux estimation and wind power management. Global observations indicate that the surface wind speed probability density function (PDF) is characterized by a Weibull-like PDF during the day and a nighttime PDF with considerably greater skewness. Consideration of long-term tower observations at Cabauw, the Netherlands, indicates that this nighttime skewness is a shallow feature connected to the formation of a stably stratified nocturnal boundary layer. The observed diurnally varying vertical structure of the leading three climatological moments of near-surface wind speed (mean, standard deviation, and skewness) and the wind power density at the Cabauw site can be successfully simulated using the single-column version of the Canadian Centre for Climate Modelling and Analysis (CCCma) fourth-generation atmospheric general circulation model (CanAM4) with a new semiempirical diagnostic turbulent kinetic energy (TKE) scheme representing downgradient turbulent transfer processes for cloud-free conditions. This model also includes a simple stochastic representation of intermittent turbulence at the boundary layer inversion. It is found that the mean and the standard deviation of wind speed are most influenced by large-scale “weather” variability, while the shape of the PDF is influenced by the intermittent mixing process. This effect is quantitatively dependent on the asymptotic flux Richardson number, which determines the Prandtl number in stable flows. High vertical resolution near the land surface is also necessary for realistic simulation of the observed fine vertical structure of wind speed distribution.
Atlantic Warm-Pool Variability in the IPCC AR4 CGCM Simulations
Authors: Liu Hailong , Wang Chunzai , Lee Sang-Ki , Enfield David 
Published: May 2012

Abstract
This study investigates Atlantic warm pool (AWP) variability in the twentieth century and preindustrial simulations of coupled GCMs submitted to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). In the twentieth-century simulations, most coupled models show very weak AWP variability, represented by an AWP area index, because of the cold SST bias in the AWP. Among the IPCC models, a higher AWP SST index corresponds to increased net downward shortwave radiation and decreased low-level cloud fraction during the AWP peak season. This suggests that the cold SST bias in the AWP region is at least partly caused by an excessive amount of simulated low-level cloud, which blocks shortwave radiation from reaching the sea surface. AWP natural variability is examined in preindustrial simulations. Spectral analysis reveals that only multidecadal band variability of the AWP is significant in observations. All models successfully capture the multidecadal band, but they show that interannual and/or decadal variability is also significant. On the multidecadal time scale, the global SST difference pattern between large AWP years and small AWP years resembles the geographic pattern of the AMO for most coupled models. Observational analysis indicates that both positive ENSO phase and negative NAO phase in winter correspond to reduced trade winds in the AWP region. The westerly anomalies induced by positive ENSO and negative NAO lead to local heating and warm SST from March to May and February to April, respectively. This behavior as a known feature of anomalous AWP growth is well captured by only five models.
Greenland Freshwater Runoff. Part I: A Runoff Routing Model for Glaciated and Nonglaciated Landscapes (HydroFlow)
Authors: Liston Glen E. , Mernild Sebastian H. 
Published: May 2012

Abstract
A gridded linear-reservoir runoff routing model (HydroFlow) was developed to simulate the linkages between runoff production from land-based snowmelt and icemelt processes and the associated freshwater fluxes to downstream areas and surrounding oceans. HydroFlow was specifically designed to account for glacier, ice sheet, and snow-free and snow-covered land applications. Its performance was verified for a test area in southeast Greenland that contains the Mittivakkat Glacier, the local glacier in Greenland with the longest observed time series of mass-balance and ice-front fluctuations. The time evolution of spatially distributed gridcell runoffs required by HydroFlow were provided by the SnowModel snow-evolution modeling system, driven with observed atmospheric data, for the years 2003 through 2010. The spatial and seasonal variations in HydroFlow hydrographs show substantial correlations when compared with observed discharge coming from the Mittivakkat Glacier area and draining into the adjacent ocean. As part of its discharge simulations, HydroFlow creates a flow network that links the individual grid cells that make up the simulation domain. The collection of networks that drain to the ocean produced a range of runoff values that varied most strongly according to catchment size and percentage and elevational distribution of glacier cover within each individual catchment. For 2003–10, the average annual Mittivakkat Glacier region runoff period was 200 ± 20 days, with a significant increase in annual runoff over the 8-yr study period, both in terms of the number of days (30 days) and in volume (54.9 × 106 m3).
CALIPSO-Derived Three-Dimensional Structure of Aerosol over the Atlantic Basin and Adjacent Continents
Authors: Adams Aaron M. , Prospero Joseph M. , Zhang Chidong 
Published: May 2012

Abstract
Accurate modeling of the impact of aerosols on climate requires a detailed understanding of the vertical distribution of aerosols. The Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) provides continuous high-resolution vertical profiles of aerosol properties on a near-global scale. Here the CALIPSO Vertical Feature Mask is used to document the three-dimensional (3D) frequency-of-occurrence distribution of aerosols over a broad region of the Atlantic Ocean, Africa, Europe, and the Americas. The 3D distributions illustrate the seasonal cycle in the zonal and meridional variability of the vertical profiles of mineral dust, biomass-burning smoke, polluted dust (external mixture of dust and smoke), and polluted continental aerosol, and also of their emissions sources and transport pathways. Four aerosol domains stand out in the product: dust over North Africa and the Middle East and smoke over southern Africa and South America. The transport pathways of African dust and smoke over the Atlantic are evident. The intertropical convergence zone (ITCZ) plays a clear role in limiting the southward transport of North African dust and northward transport of South African smoke. Dust and smoke are mixed in the ITCZ and consequently the highest probability of polluted dust is found there, even though the probabilities of dust and smoke in this region are relatively low. The mixing of dust and pollution has significant implications for cloud microphysical processes over a broad region of the Atlantic.
The Reliability of Antarctic Tropospheric Pressure and Temperature in the Latest Global Reanalyses
Authors: Bracegirdle Thomas J. , Marshall Gareth J. 
Published: May 2012

Abstract
In this study, surface and radiosonde data from staffed Antarctic observation stations are compared to output from five reanalyses [Climate Forecast System Reanalysis (CFSR), 40-yr ECMWF Re-Analysis (ERA-40), ECMWF Interim Re-Analysis (ERA-Interim), Japanese 25-year Reanalysis (JRA-25), and Modern Era Retrospective-Analysis for Research and Applications (MERRA)] over three decades spanning 1979–2008. Bias and year-to-year correlation between the reanalyses and observations are assessed for four variables: mean sea level pressure (MSLP), near-surface air temperature (Ts), 500-hPa geopotential height (H500), and 500-hPa temperature (T500).
It was found that CFSR and MERRA are of a sufficiently high resolution for the height of the orography to be accurately reproduced at coastal observation stations. Progressively larger negative Ts biases at these coastal stations are apparent for reanalyses in order of decreasing resolution. However, orography height bias cannot explain large winter warm biases in CFSR, JRA-25, and MERRA (11.1°, 10.2°, and 7.9°C, respectively) at Amundsen–Scott and Vostok, which have been linked to problems with representing the surface energy balance.
Linear trends in the annual-mean T500 and H500 averaged over Antarctica as a whole were found to be most reliable in CFSR, ERA-Interim, and MERRA, none of which show significant trends over the period 1979–2008. In contrast JRA-25 shows significant negative trends over 1979–2008 and ERA-40 gives significant positive trends during the 1980s (evident in both T500 and H500). Comparison to observations indicates that the positive trend in ERA-40 is spurious. At the smaller spatial scale of individual stations all five reanalyses have some spurious trends. However, ERA-Interim was found to be the most reliable for MSLP and H500 trends at station locations.
An Enhanced Influence of Tropical Indian Ocean on the South Asia High after the Late 1970s
Authors: Qu Xia , Huang Gang 
Published: May 2012

Abstract
The tropical Indian Ocean (TIO)’s influence on the South Asia high (SAH)’s intensity experiences a decadal change in the late 1970s; after (before) the decadal shift, the influence is significant (insignificant). The present study investigates the role of tropospheric temperature in relaying the impact of sea surface temperature (SST) to the SAH and the change in the TIO’s influence. During the two epochs, the local tropospheric temperature responses to the TIO warming are distinct—more significant during the second epoch. It is inferred that this change may be responsible for the strengthening of the TIO’s influence on the SAH. Encouragingly, the ensemble simulations accurately capture the time of the decadal change, indicating that the enhanced influence is attributed to the SST forcing.
There are two possible reasons for the change in the TIO–SAH relationship. The first reason is the change in the locations of the SST anomalies in the TIO. During the second epoch, positive SST anomalies lie in the Indian Ocean warm pool. Through the background vigorous convection and moist adjustment, the SST anomalies affect largely the tropospheric temperature and thus the SAH. The second reason is the decadal change in mean SST and the SST variability. During the recent decades, both the background SST and the variability of the TIO SST increase, which enhance the influence of the SST anomalies on the atmosphere. The influence of the remote oceanic forcing on the enhanced TIO–SAH relationship and its comparison with the contribution of the TIO SST are also discussed.
What Drives the Variability of Evaporative Demand across the Conterminous United States?
Authors: Hobbins Michael , Wood Andrew , Streubel David , Werner Kevin 
Published: May 2012

AbstractTo understand the sources of temporal and spatial variability of atmospheric evaporative demand across the conterminous United States (CONUS), a mean-value, second-moment uncertainty analysis is applied to a spatially distributed dataset of daily synthetic pan evaporation for 1980–2009. This evaporative demand measure is from the “PenPan” model, which is a combination equation calibrated to mimic observations from U.S. class-A evaporation pans and here driven by six North American Land Data Assimilation System variables: temperature, specific humidity, station pressure, wind speed, and downwelling shortwave and longwave radiation. The variability of evaporative demand is decomposed across various time scales into contributions from these drivers. Contrary to popular expectation and much hydrologic practice, temperature is not always the most significant driver of temporal variability in evaporative demand, particularly at subannual time scales. Instead, depending on the season, one of four drivers (temperature, specific humidity, downwelling shortwave radiation, and wind speed) dominates across different regions of CONUS. Temperature generally dominates in the northern continental interior. This analysis assists land surface modelers in balancing parameter parsimony and physical representativeness. Patterns of dominant drivers are shown to cycle seasonally, with clear implications for modeling evaporative demand in operational hydrology or as a metric of climate change and variability. Depending on the region and season, temperature, specific humidity, downwelling shortwave radiation, and wind speed must together be examined, with downwelling longwave radiation as a secondary input. If any variable may be ignored, it is atmospheric pressure. Parameterizations of evaporative demand based solely on temperature should be avoided at all time scales.