bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Density Lipoproteins Prevent the Oxidized Low-Density Lipoprotein–Induced Endothelial Growth Factor Receptor Activation and Subsequent Matrix Metalloproteinase-2 Upregulation
Authors: Robbesyn Fanny , Augé Nathalie , Vindis Cécile , Cantero Anne-Valérie , Barbaras Ronald , Negre-Salvayre Anne , Salvayre Robert 
Published: April 2005

Objectives—The atherogenic oxidized low-density lipoprotein (oxLDL) induces the formation of carbonyl-protein adducts and activates the endothelial growth factor receptor (EGFR) signaling pathway, which is now regarded as a central element for signal transduction. We aimed to investigate whether and by which mechanism the anti-atherogenic high-density lipoprotein (HDL) prevents these effects of oxLDL.Methods and Results—In vascular cultured cells, HDL and apolipoprotein A-I inhibit oxLDL-induced EGFR activation and subsequent signaling by acting through 2 separate mechanisms. First, HDL, like the aldehyde scavenger dinitrophenyl hydrazine, prevented the formation of oxLDL-induced carbonyl–protein adducts and 4-hydroxynonenal (HNE)–EGFR adducts. Secondly, HDL enhanced the cellular antioxidant defenses by preventing (through a scavenger receptor class B-1 (SR-BI)–dependent mechanism) the increase of intracellular reactive oxygen species (ROS) and subsequent EGFR activation triggered by oxLDL or H2O2. A pharmacological approach suggests that this protective effect of HDL is independent of cellular glutathione level and glutathione peroxidase activity, but it requires catalase activity. Finally, we report that oxLDL upregulates both membrane type 1 (MT1)-matrix metalloproteinase-1 (MT1-MMP) and MMP-2 through an EGFR-dependent mechanism and that HDL inhibits these events.Conclusions—HDLs block in vitro oxLDL-induced EGFR signaling and subsequent MMP-2 activation by inhibiting carbonyl adducts formation and cellular oxidative stress. These effects of HDL may participate to reduce cell activation, excessive remodeling, and alteration of the vascular wall.
Trends and Variability in U.S. Corn Yields Over the Twentieth Century
Authors: Kucharik Christopher J. , Ramankutty Navin 
Published: April 2005

AbstractThe United States is currently responsible for 40%–45% of the world’s corn supply and 70% of total global exports [the U.S. Department of Agriculture–National Agricultural Statistics Service (USDA–NASS)]. Therefore, analyses of the spatial and temporal patterns of historical U.S. corn yields might provide insight into future crop-production potential and food security. In this study, county-level maize yield data from 1910 to 2001 were used to characterize the spatial heterogeneity of yield growth rates and interannual yield variability across the U.S. Corn Belt.Widespread decadal-scale changes in corn yield variability and yield growth rates have occurred since the 1930s across the Corn Belt, but the response has varied substantially with geographic location. Northern portions of the Great Plains have experienced consistently high interannual corn yield variability, averaging 30%–40% relative to the mean. Increasing usage of irrigation in Nebraska, Kansas, and Texas, since the 1950s, has helped boost yields by 75%–90% over rain-fed corn, creating a yield gap of 2–4 T ha−1 between irrigated and nonirrigated corn that could potentially be exploited in other regions. Furthermore, irrigation has reduced interannual variability by a factor of 3 in these same regions. A small region from eastern Iowa into northern Illinois and southern Wisconsin has experienced minimal interannual yield variability, averaging only 6%–10% relative to mean yields.This paper shows that the choice of time period used for statistical analysis impacted conclusions drawn about twentieth-century trends in corn yield variability. Widespread increases in yield variability were apparent from 1950 onward, but were not significant over the entire 1930–2001 period. There is also evidence that yield variability decreased from the early 1990s to 2001. Corn yield growth rates peaked at an annual-average rate of 3%–5% in the 1960s (124.5 kg ha−1 yr−1), but have steadily declined to a relative rate of 0.78% yr−1 (49.2 kg ha−1 yr−1) during the 1990s. A general inverse relationship between increasing corn yield and decreasing yield growth rates was noted after county-level yields reached 4 T ha−1, suggesting that widespread, significant increases in corn yield are not likely to take place in the future, particularly on irrigated land, without a second agricultural revolution.
Some Characteristics of Model-Predicted Precipitation during the Summer Monsoon over India
Authors: Basu B. K. 
Published: April 2005

AbstractFor the summer monsoon seasons of 1995, 1996, and 1997 the day-1 to day-4 forecasts of precipitation from both the National Centre for Medium Range Weather Forecasting (NCMRWF) and the European Centre for Medium-Range Forecasts (ECMWF) models reproduce the main features of the observed precipitation pattern when averaged over the whole season. On average, less than 30% of all rain gauge stations in India report rain on a given day during the monsoon season. The number of observed rainy days increases to 41% after spatial averaging over ECMWF model grid boxes and to 50% after spatial averaging over NCMRWF model grid boxes. The NCMRWF model forecasts have 10%–15% more rainy days, mostly in the light or moderate precipitation categories, when compared with the spatial average of observed values. Seasonal accumulated values of all of India’s average precipitation show a slight increase with the forecast lead time for the NCMRWF model and a small decrease for the ECMWF model. The weekly accumulated values of forecast precipitation from both models, averaged over the whole of India, are in good phase relationship (∼0.9 in most cases) with the observed value for forecasts with a lead time up to day 4. Values of statistical parameters, based on the frequency of occurrence in various classes, indicate that the NCMRWF model has some skill in predicting precipitation over India during the summer monsoon. The NCMRWF model forecasts have higher trend correlation with the observed precipitation over India than do the ECMWF model forecasts. The mean error in precipitation is, however, much less in the ECMWF model forecasts, and the spatial distribution of seasonal average medium-range forecasts of ECMWF is closer to that observed along the west coast mountain ridgeline.
Radar Refractivity Retrieval: Validation and Application to Short-Term Forecasting
Authors: Weckwerth Tammy M. , Pettet Crystalyne R. , Fabry Frédéric , Park Shin Ju , LeMone Margaret A. , Wilson James W. 
Published: April 2005

AbstractThis study will validate the S-band dual-polarization Doppler radar (S-Pol) radar refractivity retrieval using measurements from the International H2O Project conducted in the southern Great Plains in May–June 2002. The range of refractivity measurements during this project extended out to 40–60 km from the radar. Comparisons between the radar refractivity field and fixed and mobile mesonet refractivity values within the S-Pol refractivity domain show a strong correlation. Comparisons between the radar refractivity field and low-flying aircraft also show high correlations. Thus, the radar refractivity retrieval provides a good representation of low-level atmospheric refractivity. Numerous instruments that profile the temperature and moisture are also compared with the refractivity field. Radiosonde measurements, Atmospheric Emitted Radiance Interferometers, and a vertical-pointing Raman lidar show good agreement, especially at low levels. Under most daytime summertime conditions, radar refractivity measurements are representative of an ∼250-m-deep layer. Analyses are also performed on the utility of refractivity for short-term forecasting applications. It is found that the refractivity field may detect low-level boundaries prior to the more traditional radar reflectivity and Doppler velocity fields showing their existence. Data from two days on which convection initiated within S-Pol refractivity range suggest that the refractivity field may exhibit some potential utility in forecasting convection initiation. This study suggests that unprecedented advances in mapping near-surface water vapor and subsequent improvements in predicting convective storms could result from implementing the radar refractivity retrieval on the national network of operational radars.
Simultaneous Observations of Cirrus Clouds with a Millimeter-Wave Radar and the MU Radar
Authors: Wada Eiko , Hashiguchi Hiroyuki , Yamamoto Masayuki K. , Teshiba Michihiro , Fukao Shoichiro 
Published: April 2005

AbstractObservations of frontal cirrus clouds were conducted with the scanning millimeter-wave radar at the Shigaraki Middle and Upper Atmosphere (MU) Radar Observatory in Shiga, Japan, during 30 September–13 October 2000. The three-dimensional background winds were also observed with the very high frequency (VHF) band MU radar. Comparing the observational results of the two radars, it was found that the cirrus clouds appeared coincident with the layers of the strong vertical shear of the horizontal winds, and they developed and became thicker under the condition of the strong vertical shear of the horizontal wind and updraft. The result of the radiosonde observation indicated that Kelvin–Helmholtz instability (KHI) occurred at 8–9-km altitudes because of the strong vertical shear of the horizontal wind. The warm and moist air existed above the 8.5-km altitude, and the cold and dry air existed below the 8.5-km altitude. As a result of the airmass mixing of air above and below the 8.5-km altitudes, the cirrus clouds were formed. The updraft, which existed at 8.5–12-km altitude, caused the development of the cirrus clouds with the thickness of &gt;2 km. By using the scanning millimeter-wave radar, the three-dimensional structure of cell echoes formed by KHI for the first time were successfully observed.
The Unusual Midwinter Warming in the Southern Hemisphere Stratosphere 2002: A Comparison to Northern Hemisphere Phenomena
Authors: Krüger Kirstin , Naujokat Barbara , Labitzke Karin 
Published: April 2005

Abstract
A strong midwinter warming occurred in the Southern Hemisphere (SH) stratosphere in September 2002. Based on experiences from the Northern Hemisphere (NH), this event can be defined as a major warming with a breakdown of the polar vortex in midwinter, which has never been detected so far in the SH since observations began at the earliest in the 1940s. Minor midwinter warmings occasionally occurred in the SH, but a strong interannual variability, as is present in winter and spring in the NH, has been explicitly associated with the spring reversals.
A detailed analysis of this winter reveals the dominant role of eastward-traveling waves and their interaction with quasi-stationary planetary waves forced in the troposphere. Such wave forcing, finally leading to the sudden breakdown of the vortex, is a familiar feature of the northern winter stratosphere. Therefore, the unusual development of this Antarctic winter is described in the context of more than 50 Arctic winters, concentrating on winters with similar wave perturbations. The relevance of preconditioning of major warmings by traveling and quasi-stationary planetary waves is discussed for both hemispheres.
Evidence against an Antarctic Stratospheric Vortex Split during the Periods of Pre-IGY Temperature Measurements
Authors: Naujokat Barbara , Roscoe Howard K. 
Published: April 2005

Abstract
Historic upper-air observations from Antarctica are inspected to investigate the uniqueness of the vortex split in the Antarctic spring of 2002. No comprehensive meteorological observations are available prior to the International Geophysical Year (IGY) 1957/58, but stratospheric temperature observations from single stations provide evidence of varying strengths against the possibility of a split vortex in 1940 and in the early and middle 1950s.
The Splitting of the Stratospheric Polar Vortex in the Southern Hemisphere, September 2002: Dynamical Evolution
Authors: Charlton Andrew J. , O’Neill Alan , Lahoz William A. , Berrisford Paul 
Published: April 2005

Abstract
The polar vortex of the Southern Hemisphere (SH) split dramatically during September 2002. The large-scale dynamical effects were manifest throughout the stratosphere and upper troposphere, corresponding to two distinct cyclonic centers in the upper troposphere–stratosphere system. High-resolution (T511) ECMWF analyses, supplemented by analyses from the Met Office, are used to present a detailed dynamical analysis of the event. First, the anomalous evolution of the SH polar vortex is placed in the context of the evolution that is usually witnessed during spring. Then high-resolution fields of potential vorticity (PV) from ECMWF are used to reveal several dynamical features of the split. Vortex fragments are rapidly sheared out into sheets of high (modulus) PV, which subsequently roll up into distinct synoptic-scale vortices. It is proposed that the stratospheric circulation becomes hydrodynamically unstable through a significant depth of the troposphere–stratosphere system as the polar vortex elongates.
Stratosphere–Troposphere Coupling in the Southern Hemisphere
Authors: Thompson David W. J. , Baldwin Mark P. , Solomon Susan 
Published: April 2005

AbstractThis study examines the temporal evolution of the tropospheric circulation following large-amplitude variations in the strength of the Southern Hemisphere (SH) stratospheric polar vortex in data from 1979 to 2001 and following the SH sudden stratospheric warming of 2002. In both cases, anomalies in the strength of the SH stratospheric polar vortex precede similarly signed anomalies in the tropospheric circulation that persist for more than 2 months. The SH tropospheric circulation anomalies reflect a bias in the polarity of the SH annular mode (SAM), a large-scale pattern of climate variability characterized by fluctuations in the strength of the SH circumpolar flow. Consistent with the climate impacts of the SAM, variations in the stratospheric polar vortex are also followed by coherent changes in surface temperatures throughout much of Antarctica. The results add to a growing body of evidence that suggests that stratospheric variability plays an important role in driving climate variability at Earth’s surface on a range of time scales.
ECMWF Analyses and Forecasts of Stratospheric Winter Polar Vortex Breakup: September 2002 in the Southern Hemisphere and Related Events
Authors: Simmons Adrian , Hortal Mariano , Kelly Graeme , McNally Anthony , Untch Agathe , Uppala Sakari 
Published: April 2005

Abstract
Breakup of the polar stratospheric vortex in the Northern Hemisphere is an event that is known to be predictable for up to a week or so ahead. This is illustrated using data from the 45-yr ECMWF Re-Analysis (ERA-40) for the sudden warmings of January 1958 and February 1979 and operational ECMWF data for February 2003. It is then shown that a similar level of skill was achieved in operational forecasts for the split of the southern stratospheric vortex in late September 2002. The highly unusual flow conditions nevertheless exposed a computational instability of the forecast model. Analyses and forecasts from reruns using improved versions of the forecasting system are presented. Isentropic maps of potential vorticity and specific humidity provide striking pictures of the advective processes at work. Forecasts as well as analyses are shown to be in good agreement with radiosonde measurements of the temperature changes associated with vortex movement, distortion, and breakup during August and September. Forecasts from 17 September onward capture the remarkable temperature rise of about 60°C recorded at 20 hPa by the Halley radiosonde station as the vortex split. Objective forecast verification and data denial experiments are used to characterize the performance of the observing and data assimilation systems and to infer overall forecast, analysis, and observation accuracy. The observations and analyses from 1957 onward in the ERA-40 archive confirm the extreme nature of the 2002 event. Secondary vortex development by barotropic instability is also discussed; in analyses for early October 2002, the process is active in the breakup of the weaker of the two vortices formed by the late-September split.
The Unusual Southern Hemisphere Stratosphere Winter of 2002
Authors: Newman Paul A. , Nash Eric R. 
Published: April 2005

Abstract
The Southern Hemisphere (SH) stratospheric winter of 2002 was the most unusual winter yet observed in the SH climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen–Palm flux vectors and autoregression time series. Strong levels of planetary waves were observed in the midlatitude lower troposphere. The combinations of strong tropospheric waves with a low index of refraction at the tropopause resulted in the large stratospheric wave forcing. The wave events tended to occur irregularly over the course of the winter, and the cumulative effect of these waves was to precondition the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major stratospheric warming in the SH and split the Antarctic ozone hole. The combined effect of all of the 2002 winter wave events resulted in the smallest ozone hole observed since 1988. The sequence of stratospheric wave events was also found to be strongly associated with unusually strong levels of wave 1 in the SH tropospheric subtropics.
Vertical Structure of the Anomalous 2002 Antarctic Ozone Hole
Authors: Kondragunta S. , Flynn L. E. , Neuendorffer A. , Miller A. J. , Long C. , Nagatani R. , Zhou S. , Beck T. , Beach E. , McPeters R. , Stolarski R. , Bhartia P. K. , DeLand M. T. , Huang L.-K. 
Published: April 2005

Abstract
Ozone estimates from observations by the NOAA-16 Solar Backscattered Ultraviolet (SBUV/2) instrument and Television Infrared Observation Satellite (TIROS-N) Operational Vertical Sounder (TOVS) are used to describe the vertical structure of ozone in the anomalous 2002 polar vortex. The SBUV/2 total ozone maps show that the ozone hole was pushed off the Pole and split into two halves due to a split in the midstratospheric polar vortex in late September. The vortex split and the associated transport of high ozone from midlatitudes to the polar region reduced the ozone hole area from 18 × 106 km2 on 20 September to 3 × 106 km2 on 27 September 2002. A 23-yr time series of SBUV/2 daily zonal mean total ozone amounts between 70° and 80°S shows record high values [385 Dobson units (DU)] during the late-September 2002 warming event. The transport and descent of high ozone from low latitudes to high latitudes between 60 and 15 mb contributed to the unusual increase in total column ozone and a small ozone hole estimated using the standard criterion (area with total ozone &lt; 220 DU). In contrast, TOVS observations show an ozone-depleted region between 0 and 24 km, indicating that ozone destruction was present in the elongated but unsplit vortex in the lower stratosphere. During the warming event, the low-ozone regions in the middle and upper stratosphere were not vertically aligned with the low-ozone regions in the upper troposphere and lower stratosphere. This offset in the vertical distribution of ozone resulted in higher total column ozone masking the ozone depletion in the lower stratosphere and resulting in a smaller ozone hole size estimate from satellite total ozone data.
GOME Observations of Stratospheric Trace Gas Distributions during the Splitting Vortex Event in the Antarctic Winter of 2002. Part I: Measurements
Authors: Richter Andreas , Wittrock Folkard , Weber Mark , Beirle Steffen , Kühl Sven , Platt Ulrich , Wagner Thomas , Wilms-Grabe Walburga , Burrows John P. 
Published: April 2005

Abstract
Measurements from the Global Ozone Monitoring Experiment (GOME) are used to study the chemical evolution of the stratosphere during the unusual 2002 winter in the Southern Hemisphere. The results show that chlorine activation as indicated by OClO columns was similar to previous years in the vortex until the major warming on 26 September 2002 after which it decreased rapidly. Similarly, NO2 columns were only slightly larger than in previous years before the warming, indicating strong denoxification and probably also denitrification. After the warming, very large NO2 columns were observed for a few days, which then decreased again as the vortex reestablished itself until the final warming. Ozone columns were much larger than in any previous year from September onward, mainly as a result of the unusual dynamical situation. Analysis of the global long-term time series of GOME measurements since 1996 provides a unique opportunity to set the austral winter 2002 into perspective. The GOME data reveal the large difference in variability of chlorine activation between the two hemispheres, whereas denoxification shows surprisingly little variation from year to year in both hemispheres. However, NO2 depletion in the Southern Hemisphere is usually sustained for about one month longer in the Antarctic stratosphere as a result of the stable vortex. Compared to the observations in the Northern Hemisphere, the austral winter 2002 was still stable and cold and had a high potential for chemical ozone destruction.
Model Simulations of the Impact of the 2002 Antarctic Ozone Hole on the Midlatitudes
Authors: Marchand M. , Bekki S. , Pazmino A. , Lefèvre F. , Godin-Beekmann S. , Hauchecorne A. 
Published: April 2005

Abstract
The 2002 Antarctic winter was characterized by unusually strong wave activity. The frequency and intensity of the anomalies increased in August and early September with a series of minor stratospheric warmings and culminated in a major stratospheric warming in late September. A three-dimensional high-resolution chemical transport model is used to estimate the effect of the exceptional 2002 Antarctic winter on chemical ozone loss in the midlatitudes and in polar regions. An ozone budget analysis is performed using a range of geographical and chemical ozone tracers. To highlight the unusual behavior of the 2002 winter, the same analysis is performed for the more typical 2001 winter. The ability of the model to reproduce the evolution of polar and midlatitude ozone during these two contrasted winters is first evaluated against ozonesonde measurements at middle and high latitudes. The evolution of the model-calculated 2002 ozone loss within the deep vortex core is found to be somewhat similar to that seen in the 2001 simulation until November, which is consistent with a lower-stratospheric vortex core remaining more or less isolated even during the major warming. However, the simulations suggest that the wave activity anomalies in 2002 enhanced mixing well before the major warming within the usually weakly mixed vortex edge region and, to a lesser extent, within the surrounding extravortex region. As a result of the increased permeability of the vortex edge, the export of chemically activated vortex air is more efficient during the winter in 2002 than in 2001. This has a very noticeable impact on the model-calculated midlatitude ozone loss, with destruction rates being about 2 times higher during August and September in 2002 compared to 2001. If the meteorological conditions of 2002 were to become more prevalent in the future, Antarctic polar ozone depletion would certainly be reduced, especially in the vortex edge region. However, it is also likely that polar chemical activation would affect midlatitude ozone earlier in the winter.