bluuebunny/crossref_metadata_2025_split huggingface dataset:
ETA-receptor blockade impairs vasoconstriction after hemorrhage in xenon-anesthetized dogs treated with an AT1-receptor antagonistThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.
Authors: Höhne Claudia , Francis Roland C.E. , Pickerodt Philipp , Klein Adrian , Kaisers Udo , Boemke Willehad 
Published: May 2008

The effects of endothelin receptor subtype A (ETA) blockade on hemodynamics and hormonal adaptation during hemorrhage were studied in xenon/remifentanil-anesthetized dogs (n = 6) pretreated with an angiotensin II type 1 (AT1)-receptor blocker. Controls: after a baseline awake period, anesthesia was induced in the dogs with propofol and maintained with xenon/remifentanil (baseline anesthesia). Sixty minutes later, 20 mL·kg–1 of blood was withdrawn within 5 min and the dogs observed for another hour (hemorrhage). AT1 group followed the same protocol as controls except the AT1-receptor blocker losartan (i.v. 100 μg·kg–1·min–1) was started at the beginning of the experiment. AT1+ETA group was the same as AT1 group but with the addition of the ETA-receptor blocker atrasentan (i.v. 1 mg·kg–1, then 0.01 mg·kg–1·min–1). In controls, mean arterial pressure (MAP) remained unchanged during baseline anesthesia, whereas systemic vascular resistance (SVR) increased from 3282 ± 281 to 7321 ± 803 dyn·s·cm–5, heart rate (HR) decreased from 86 ± 4 to 40 ± 3 beats·min–1, and cardiac output (CO) decreased from 2.3 ± 0.2 to 0.9 ± 0.1 L·min–1 (p < 0.05), with no further changes after hemorrhage. In AT1-inhibited dogs, MAP (71 ± 6 mm Hg) and SVR (5939 ± 611 dyn·s·cm–5) were lower during baseline anesthesia and after hemorrhage, but greater than those in AT1+ETA (66 ± 7 mm Hg, 5034 ± 658 dyn·s·cm–5) (p < 0.05). HR and CO were not different between groups. Plasma concentration of vasopressin was highest with AT1+ETA inhibition after hemorrhage. Combined AT1+ETA-receptor blockade impaired vasoconstriction more than did AT1-receptor blockade alone, both during baseline xenon anesthesia and after hemorrhage. Even a large increase in vasoconstrictor hormones could not prevent the decrease in blood pressure and the smaller increase in SVR. Thus, endothelin is an important vasoconstrictor during hemorrhage, and both endothelin and angiotensin II are essential hormones for cardiovascular stabilization after hemorrhage.
Genesis of Tropical Storm Eugene (2005) from Merging Vortices Associated with ITCZ Breakdowns. Part I: Observational and Modeling Analyses
Authors: Kieu Chanh Q. , Zhang Da-Lin 
Published: May 2008

Abstract
Although tropical cyclogenesis occurs over all tropical warm ocean basins, the eastern Pacific appears to have the highest frequency of tropical cyclogenesis events per unit area. In this study, tropical cyclogenesis from merging mesoscale convective vortices (MCVs) associated with breakdowns of the intertropical convergence zone (ITCZ) is examined. This is achieved through a case study of the processes leading to the genesis of Tropical Storm Eugene (2005) over the eastern Pacific using the National Centers for Environmental Prediction reanalysis, satellite data, and 4-day multinested cloud-resolving simulations with the Weather Research and Forecast (WRF) model at the finest grid size of 1.33 km.
Observational analyses reveal the initiations of two MCVs on the eastern ends of the ITCZ breakdowns that occurred more than 2 days and 1000 km apart. The WRF model reproduces their different movements, intensity and size changes, and vortex–vortex interaction at nearly the right timing and location at 39 h into the integration as well as the subsequent track and intensity of the merger in association with the poleward rollup of the ITCZ. Model results show that the two MCVs are merged in a coalescence and capture mode due to their different larger-scale steering flows and sizes. As the two MCVs are being merged, the low- to midlevel potential vorticity and tangential flows increase substantially; the latter occurs more rapidly in the lower troposphere, helping initiate the wind-induced surface heat exchange process leading to the genesis of Eugene with a diameter of 400 km. Subsequently, the merger moves poleward with characters of both MCVs. The simulated tropical storm exhibits many features that are similar to a hurricane, including the warm-cored “eye” and the rotating “eyewall.” It is also shown that vertical shear associated with a midlevel easterly jet leads to the downshear tilt and the wavenumber-1 rainfall structures during the genesis stage, and the upshear generation of moist downdrafts in the vicinity of the eyewall in the minimum equivalent potential temperature layer. Based on the above results, it is concluded that the ITCZ provides a favorable environment with dynamical instability, high humidity, and background vorticity, but it is the merger of the two MCVs that is critical for the genesis of Eugene. The storm decays as it moves northwestward into an environment with increasing vertical shear, dry intrusion, and colder sea surface temperatures. The results appear to have important implications for the high frequency of development of tropical cyclones in the eastern Pacific.
Attribution of Declining Western U.S. Snowpack to Human Effects
Authors: Pierce David W. , Barnett Tim P. , Hidalgo Hugo G. , Das Tapash , Bonfils Céline , Santer Benjamin D. , Bala Govindasamy , Dettinger Michael D. , Cayan Daniel R. , Mirin Art , Wood Andrew W. , Nozawa Toru 
Published: May 2008

Abstract
Observations show snowpack has declined across much of the western United States over the period 1950–99. This reduction has important social and economic implications, as water retained in the snowpack from winter storms forms an important part of the hydrological cycle and water supply in the region. A formal model-based detection and attribution (D–A) study of these reductions is performed. The detection variable is the ratio of 1 April snow water equivalent (SWE) to water-year-to-date precipitation (P), chosen to reduce the effect of P variability on the results. Estimates of natural internal climate variability are obtained from 1600 years of two control simulations performed with fully coupled ocean–atmosphere climate models. Estimates of the SWE/P response to anthropogenic greenhouse gases, ozone, and some aerosols are taken from multiple-member ensembles of perturbation experiments run with two models. The D–A shows the observations and anthropogenically forced models have greater SWE/P reductions than can be explained by natural internal climate variability alone. Model-estimated effects of changes in solar and volcanic forcing likewise do not explain the SWE/P reductions. The mean model estimate is that about half of the SWE/P reductions observed in the west from 1950 to 1999 are the result of climate changes forced by anthropogenic greenhouse gases, ozone, and aerosols.
Pacific Decadal Oscillation and Sea Level Variability in the Bohai, Yellow, and East China Seas
Authors: Han Guoqi , Huang Weigen 
Published: May 2008

Abstract
Sea level variability off East China has been investigated based primarily on 10 years of Ocean Topography Experiment (TOPEX)/Poseidon altimetry data. The altimetric annual harmonic has a magnitude of 10 to 30 cm in amplitude and is highest in summer, agreeing well with independent tide-gauge data. After the inverse barometer effect is removed, the annual sea level cycle can be approximately accounted for by the steric height variation. Significant interannual sea level change was also observed from altimetry and tide-gauge data, with a range of ∼10 cm. The interannual and longer-term sea level variability in the altimetric data are negatively correlated (significant at the 95% confidence level) with the Pacific decadal oscillation (PDO), attributed in part to steric height change. The altimetric sea level rise rate is 0.64 cm yr−1 for the period from 1992 to 2002, consistent with the tide-gauge rate of 0.6 cm yr−1. These values are much larger than the rate of 0.24 cm yr−1 observed at the same tide gauges but for the period from 1980 to 2002, implying the sensitivity to the length of data as a result of the decadal variability. The potential role of the PDO in the interannual and longer-term sea level variability is discussed in terms of regional manifestations such as the ocean temperature and salinity and the Kuroshio transport.
A Three-Dimensional Variational Data Assimilation Scheme for the Regional Ocean Modeling System
Authors: Li Zhijin , Chao Yi , McWilliams James C. , Ide Kayo 
Published: May 2008

Abstract
A three-dimensional variational data assimilation (3DVAR) scheme has been developed within the framework of the Regional Ocean Modeling System (ROMS). This ROMS3DVAR enables the capability of predicting meso- to small-scale variations with temporal scales from hours to days in coastal oceans. To cope with particular difficulties that result from complex coastlines and bottom topography, unbalanced flows, and sparse observations, ROMS3DVAR includes novel strategies. These strategies include the implementation of three-dimensional anisotropic and inhomogeneous error correlations based on a Kronecker product, application of particular weak dynamic constraints, and implementation of efficient and reliable algorithms for minimizing the cost function. The formulation of ROMS3DVAR is presented here, and its implementation off the West Coast is currently under way.
Simulation of Synoptic- and Subsynoptic-Scale Phenomena Associated with the East Asian Summer Monsoon Using a High-Resolution GCM
Authors: Lau Ngar-Cheung , Ploshay Jeffrey J. 
Published: May 2008

Abstract
A 20-yr simulation using a global atmospheric general circulation model with a resolution of 0.5° latitude × 0.625° longitude is compared with observational findings. The primary goal of this survey is to assess the model performance in reproducing various summertime phenomena related to the continental-scale Asian monsoon in general, and the regional-scale East Asian monsoon in particular. In both model and observed atmospheres, the seasonal march of the precipitation centers associated with the Asian summer monsoon is characterized by onsets occurring earliest over the southeastern Bay of Bengal, followed by rapid northeastward advances over Indochina, the South China Sea–Philippine Sea and the western Pacific, northward evolution in the East Asian sector, as well as northwestward development over the Bay of Bengal, the Indian subcontinent, and the Arabian Sea. This onset sequence is accompanied by southwesterly low-level flows over the rainy regions, as well as northwestward migration of the 200-mb Tibetan anticyclone. Analysis of the heat sources and sinks in various regions illustrates the prominent role of condensational heating in the local energy budget during the mature phases of monsoon development. In accord with observations, the simulated monsoon rains in the East Asian sector are organized about zonally elongated “mei-yu–baiu” (plum rain) systems. These precipitation features advance to higher latitudes during the June–July period, in conjunction with displacements of the axis of the low-level anticyclone over the subtropical western Pacific. A detailed case study is performed on a prominent rainy episode in the simulation. The model is capable of reproducing the observed intense gradients in temperature, humidity, and moist static stability in the vicinity of the mei-yu–baiu front, as well as the spatial relationships between the rainband and the three-dimensional flow field. The axis of the mei-yu–baiu rainband in this event is aligned with the trajectory of a succession of mesoscale cyclonic vortices, which originate from southwestern China and travel northeastward over the Yangtze River basin.
Obstacles to High-Dimensional Particle Filtering
Authors: Snyder Chris , Bengtsson Thomas , Bickel Peter , Anderson Jeff 
Published: May 2008

Abstract
Particle filters are ensemble-based assimilation schemes that, unlike the ensemble Kalman filter, employ a fully nonlinear and non-Gaussian analysis step to compute the probability distribution function (pdf) of a system’s state conditioned on a set of observations. Evidence is provided that the ensemble size required for a successful particle filter scales exponentially with the problem size. For the simple example in which each component of the state vector is independent, Gaussian, and of unit variance and the observations are of each state component separately with independent, Gaussian errors, simulations indicate that the required ensemble size scales exponentially with the state dimension. In this example, the particle filter requires at least 1011 members when applied to a 200-dimensional state. Asymptotic results, following the work of Bengtsson, Bickel, and collaborators, are provided for two cases: one in which each prior state component is independent and identically distributed, and one in which both the prior pdf and the observation errors are Gaussian. The asymptotic theory reveals that, in both cases, the required ensemble size scales exponentially with the variance of the observation log likelihood rather than with the state dimension per se.
A Study in Weather Model Output Postprocessing: Using the Boosting Method for Thunderstorm Detection
Authors: Perler Donat , Marchand Oliver 
Published: May 2008

Abstract
In this work, a new approach to weather model output postprocessing is presented. The adaptive boosting algorithm is used to train a set of simple base classifiers with historical data from weather model output, surface synoptic observation (SYNOP) messages, and lightning data. The resulting overall method then can be used to classify weather model output to identify potential thunderstorms. The method generates a certainty measure between −1 and 1, describing how likely a thunderstorm is to occur. Using a threshold, the measure can be converted to a binary decision. When compared to a linear discriminant and a method currently employed in an expert system from the German Weather Service, boosting achieves the best validation scores. A substantial improvement of the probability of detection of up to 72% and a decrease of the false alarm rate down to 34% can be achieved for the identification of thunderstorms in model analysis. Independent of the verification results, the method has several useful properties: good cross-validation results, short learning time (≤10 min sequential run time for the experiments on a standard PC), comprehensible inner values of the underlying statistical analysis, and the simplicity of adding predictors to a running system. This paper concludes with a set of possible other applications and extensions to the presented example of thunderstorm detection.
Sμ mutation patterns suggest different progression pathways in follicular lymphoma: early direct or late from FL progenitor cells
Authors: Ruminy Philippe , Jardin Fabrice , Picquenot Jean-Michel , Parmentier Françoise , Contentin Nathalie , Buchonnet Gérard , Tison Sandrine , Rainville Vinciane , Tilly Hervé , Bastard Christian 
Published: May 2008

Abstract
Follicular lymphoma (FL) is a B-cell malignancy characterized by the t(14;18) translocation. Although sensitive to treatment, the disease remains incurable and the reason why tumor cells invariably evade treatment, leading to clinical relapse, is still unknown. Here, we tracked the clonal history of tumor cells by studying mutations introduced by activation-induced cytidine deaminase on the switch μ region of the der(14)t(14;18) during the early phase of the class-switch recombination (CSR) process. We observed frequent intraclonal variations, suggesting that CSR often remains active after the acquisition of the fully transformed phenotype. However, mutations only rarely accumulated over time, but instead showed complex evolutionary scenarios and 2 different progression pathways. The first pathway was a direct and rapid evolution from the dominant clone. The second was indirect, arising from earlier subclones usually after years of remission. A better understanding of these mechanisms might influence the future choice of treatment strategies.
CC chemokine receptor 5 gene promoter activation by the cyclic AMP response element binding transcription factor
Authors: Kuipers Hedwich F. , Biesta Paula J. , Montagne Lisette J. , van Haastert Elise S. , van der Valk Paul , van den Elsen Peter J. 
Published: May 2008

AbstractThe chemokine receptor CCR5 is implicated in the pathogenesis of various inflammatory diseases, such as multiple sclerosis (MS), atherosclerosis, transplant rejection, and autoimmunity. In previous studies, we have shown that MS lesions are characterized by enhanced expression of transcription factors associated with stress responses, ie, IRF-1, NF-κB, and CREB-1, which modulate expression of both classes of major histocompatibility complex (MHC) molecules. The expression of MHC-I and MHC-II molecules greatly overlaps with the expression of CCR5 in MS lesions. Therefore, we investigated whether these factors are also involved in the transcriptional regulation of CCR5. Using in vitro assays, we determined that neither IRF-1 nor NF-κB is involved in the activation of the CCR5 promoter. This is corroborated by the finding that these factors are not involved in the induction of endogenous CCR5 transcription in various cell types. In contrast, we show that CCR5 expression is regulated by the cAMP/CREB pathway and that interference in this pathway affects endogenous CCR5 transcription. From this, we conclude that the cAMP/CREB pathway is involved in the regulation of CCR5 transcription and that, given the ubiquitous nature of CREB-1 protein expression, additional regulatory mechanisms must contribute to cell type-specific expression of CCR5.
Genetic hitchhiking in a subdivided population of Mytilus edulis
Authors: Faure Matthieu F , David Patrice , Bonhomme François , Bierne Nicolas 
Published: May 2008

Abstract

Background
Few models of genetic hitchhiking in subdivided populations have been developed and the rarity of empirical examples is even more striking. We here provide evidences of genetic hitchhiking in a subdivided population of the marine mussel Mytilus edulis. In the Bay of Biscay (France), a patch of M. edulis populations happens to be separated from its North Sea conspecifics by a wide region occupied only by the sister species M. galloprovincialis. Although genetic differentiation between the two M. edulis regions is largely non-significant at ten marker loci (average FST~0.007), a strong genetic differentiation is observed at a single locus (FST = 0.25). We validated the outlier status of this locus, and analysed DNA sequence polymorphism in order to identify the nature of the selection responsible for the unusual differentiation.

Results
We first showed that introgression of M. galloprovincialis alleles was very weak in both populations and did not significantly affect their differentiation. Secondly, we observed the genetic signature of a selective sweep within both M. edulis populations in the form of a star-shaped clade of alleles. This clade was nearly fixed in the North Sea and was segregating at a moderate frequency in the Bay of Biscay, explaining their genetic differentiation. Incomplete fixation reveals that selection was not direct on the locus but that the studied sequence recombined with a positively selected allele at a linked locus while it was on its way to fixation. Finally, using a deterministic model we showed that the wave of advance of a favourable allele at a linked locus, when crossing a strong enough barrier to gene flow, generates a step in neutral allele frequencies comparable to the step observed between the two M. edulis populations at the outlier locus. In our case, the position of the barrier is now materialised by a large patch of heterospecific M. galloprovincialis populations.

Conclusion
High FST outlier loci are usually interpreted as being the consequence of ongoing divergent local adaptation. Combining models and data we show that among-population differentiation can also dramatically increase following a selective sweep in a structured population. Our study illustrates how a striking geographical pattern of neutral diversity can emerge from past indirect hitchhiking selection in a structured population.

Note
Nucleotide sequences reported in this paper are available in the GenBank™ database under the accession numbers EU684165 – EU684228.
An assessment of population structure in eight breeds of cattle using a whole genome SNP panel
Authors: McKay Stephanie D , Schnabel Robert D , Murdoch Brenda M , Matukumalli Lakshmi K , Aerts Jan , Coppieters Wouter , Crews Denny , Neto Emmanuel Dias , Gill Clare A , Gao Chuan , Mannen Hideyuki , Wang Zhiquan , Van Tassell Curt P , Williams John L , Taylor Jeremy F , Moore Stephen S 
Published: May 2008

Abstract

Background
Analyses of population structure and breed diversity have provided insight into the origin and evolution of cattle. Previously, these studies have used a low density of microsatellite markers, however, with the large number of single nucleotide polymorphism markers that are now available, it is possible to perform genome wide population genetic analyses in cattle. In this study, we used a high-density panel of SNP markers to examine population structure and diversity among eight cattle breeds sampled from Bos indicus and Bos taurus.

Results
Two thousand six hundred and forty one single nucleotide polymorphisms (SNPs) spanning all of the bovine autosomal genome were genotyped in Angus, Brahman, Charolais, Dutch Black and White Dairy, Holstein, Japanese Black, Limousin and Nelore cattle. Population structure was examined using the linkage model in the program STRUCTURE and Fst estimates were used to construct a neighbor-joining tree to represent the phylogenetic relationship among these breeds.

Conclusion
The whole-genome SNP panel identified several levels of population substructure in the set of examined cattle breeds. The greatest level of genetic differentiation was detected between the Bos taurus and Bos indicus breeds. When the Bos indicus breeds were excluded from the analysis, genetic differences among beef versus dairy and European versus Asian breeds were detected among the Bos taurus breeds. Exploration of the number of SNP loci required to differentiate between breeds showed that for 100 SNP loci, individuals could only be correctly clustered into breeds 50% of the time, thus a large number of SNP markers are required to replace the 30 microsatellite markers that are currently commonly used in genetic diversity studies.