bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exponential Smallness of Inertia–Gravity Wave Generation at Small Rossby Number
Authors: Vanneste J. 
Published: May 2008

AbstractThis paper discusses some of the mechanisms whereby fast inertia–gravity waves can be generated spontaneously by slow, balanced atmospheric and oceanic flows. In the small Rossby number regime relevant to midlatitude dynamics, high-accuracy balanced models, which filter out inertia–gravity waves completely, can in principle describe the evolution of suitably initialized flows up to terms that are exponentially small in the Rossby number ɛ, that is, of the form exp(−α/ɛ) for some α &gt; 0. This suggests that the mechanisms of inertia–gravity wave generation, which are not captured by these balanced models, are also exponentially weak. This has been confirmed by explicit analytical results obtained for a few highly simplified models. These results are reviewed, and some of the exponential-asymptotic techniques that have been used in their derivation are presented. Two types of mechanisms are examined: spontaneous-generation mechanisms, which generate exponentially small waves from perfectly balanced initial conditions, and unbalanced instability mechanisms, which amplify unbalanced initial perturbations of steady flows. The relevance of the results to realistic flows is discussed.
Factors Affecting ENSO’s Period
Authors: MacMynowski Douglas G. , Tziperman Eli 
Published: May 2008

Abstract
Accurately capturing the observed mean period of ENSO in general circulation models (GCMs) is often challenging, and it is therefore useful to understand which parameters and processes affect this period. A computationally efficient simulation-based approach is used to extract both the dominant eigenvalues and corresponding eigenvectors of the linearized model from the Zebiak–Cane intermediate-complexity model of ENSO without having to directly construct the linearization. The sensitivity of the period to a variety of parameters is examined, including atmosphere–ocean coupling, atmospheric heating parameterization, thermocline depth zonal profile, western boundary reflection coefficient, atmospheric and ocean wave speeds or Rossby radii of deformation, ocean decay time, and the strength of the annual cycle. In addition to the sensitivity information, the spatial structures of the main fields (SST, thermocline thickness, and more) that are involved in period changes are obtained to aid in the physical interpretation of the sensitivities.
There are three main time lags that together compose one-half of a model ENSO period: the Rossby-plus-Kelvin wave propagation time for a wind-caused central Pacific disturbance to propagate to the western ocean and back, SST dynamics that determine the lag between eastern ocean thermocline anomalies and eastern ocean SST anomalies, and the “accumulation” lag of integrating a sufficient delayed wave signal arriving from the western ocean to cancel the eastern ocean anomalies. For any of the parameter changes considered, the eigenvector changes show that the largest contributor to the period change is from changes to the last of these three mechanisms. Physical mechanisms that affect this accumulation delay are discussed, and the case is made that any significant change to ENSO’s period is in turn likely to involve changes to this delay.
Rossby Wave Ray Tracing in a Barotropic Divergent Atmosphere
Authors: Lu Chungu , Boyd John P. 
Published: May 2008

Abstract
The effects of divergence on low-frequency Rossby wave propagation are examined by using the two-dimensional Wentzel–Kramers–Brillouin (WKB) method and ray tracing in the framework of a linear barotropic dynamic system. The WKB analysis shows that the divergent wind decreases Rossby wave frequency (for wave propagation northward in the Northern Hemisphere). Ray tracing shows that the divergent wind increases the zonal group velocity and thus accelerates the zonal propagation of Rossby waves. It also appears that divergence tends to feed energy into relatively high wavenumber waves, so that these waves can propagate farther downstream. The present theory also provides an estimate of a phase angle between the vorticity and divergence centers. In a fully developed Rossby wave, vorticity and divergence display a π/2 phase difference, which is consistent with the observed upper-level structure of a mature extratropical cyclone. It is shown that these theoretical results compare well with observations.
Finescale Structure and Dynamics of an Atmospheric Temperature Interface
Authors: Hohreiter Vincent 
Published: May 2008

Abstract
Near-ground observations of an atmospheric temperature interface in the stable nocturnal boundary layer are reported. The thermal effect of the interface passage was a 5-K decrease in temperature during a 5-min period in which changes in wind speed and wind direction were also observed. The interface is of unknown origin and horizontal and vertical scale. A 32-Hz time series of temperature measured with a sonic anemometer–thermometer at 1.5 m above ground level revealed a sharp, nonintermittent decrease in temperature (∼1 K s−1) nested within a more gradual, intermittent decrease (∼1 K min−1). A first attempt to extricate this subtle feature with regard to the relevant physics of generalized density currents is presented. It is shown that a very similar feature has been observed in the literature, but not interpreted for its physical significance. The contribution of this paper is its unique interpretation of the high-resolution temperature time series as it corresponds to the finescale physical character of an interface of density or temperature, and the motion of such an interface along the ground. Parameters of interest, including a spatial temperature gradient normal to the interface (∼1 K m−1), an interfacial thickness (2.8 m), and a thermal boundary layer for the interface (288 m), are calculated. Additionally, theoretical and empirical arguments are presented for a viscous suppression of turbulent mixing in the immediate vicinity of an interface of density or temperature.
Evaluating the Consistency between Statistically Downscaled and Global Dynamical Model Climate Change Projections
Authors: Timbal B. , Hope P. , Charles S. 
Published: May 2008

Abstract
The consistency between rainfall projections obtained from direct climate model output and statistical downscaling is evaluated. Results are averaged across an area large enough to overcome the difference in spatial scale between these two types of projections and thus make the comparison meaningful. Undertaking the comparison using a suite of state-of-the-art coupled climate models for two forcing scenarios presents a unique opportunity to test whether statistical linkages established between large-scale predictors and local rainfall under current climate remain valid in future climatic conditions. The study focuses on the southwest corner of Western Australia, a region that has experienced recent winter rainfall declines and for which climate models project, with great consistency, further winter rainfall reductions due to global warming. Results show that as a first approximation the magnitude of the modeled rainfall decline in this region is linearly related to the model global warming (a reduction of about 9% per degree), thus linking future rainfall declines to future emission paths. Two statistical downscaling techniques are used to investigate the influence of the choice of technique on projection consistency. In addition, one of the techniques was assessed using different large-scale forcings, to investigate the impact of large-scale predictor selection. Downscaled and direct model projections are consistent across the large number of models and two scenarios considered; that is, there is no tendency for either to be biased; and only a small hint that large rainfall declines are reduced in downscaled projections. Among the two techniques, a nonhomogeneous hidden Markov model provides greater consistency with climate models than an analog approach. Differences were due to the choice of the optimal combination of predictors. Thus statistically downscaled projections require careful choice of large-scale predictors in order to be consistent with physically based rainfall projections. In particular it was noted that a relative humidity moisture predictor, rather than specific humidity, was needed for downscaled projections to be consistent with direct model output projections.
The Impact of the Time Step on the Intensity of ITCZ in an Aquaplanet GCM
Authors: Mishra Saroj K. , Srinivasan J. , Nanjundiah Ravi S. 
Published: May 2008

Abstract
Several numerical experiments have been conducted using the NCAR Community Atmosphere Model, version 3 (CAM3) to examine the impact of the time step on rainfall in the intertropical convergence zone (ITCZ) in an aquaplanet. When the model time step was increased from 5 to 60 min the rainfall in the ITCZ decreased substantially. The impact of the time step on the ITCZ rainfall was assessed for a fixed spatial resolution (T63 with L26) for the semi-Lagrangian dynamical core (SLD). The increase in ITCZ rainfall at higher temporal resolution was primarily a result of the increase in large-scale precipitation. This increase in rainfall was caused by the positive feedback between surface evaporation, latent heating, and surface wind speed. Similar results were obtained when the semi-Lagrangian dynamical core was replaced by the Eulerian dynamical core. When the surface evaporation was specified, changes in rainfall were largely insensitive to temporal resolution. The impact of temporal resolution on rainfall was more sensitive to the latitudinal gradient of SST than to the magnitude of SST.
Interleukin-3 promotes expansion of hemopoietic-derived CD45+ angiogenic cells and their arterial commitment via STAT5 activation
Authors: Zeoli Annarita , Dentelli Patrizia , Rosso Arturo , Togliatto Gabriele , Trombetta Antonella , Damiano Laura , di Celle Paola Francia , Pegoraro Luigi , Altruda Fiorella , Brizzi Maria Felice 
Published: May 2008

AbstractInterleukin-3 (IL-3) released by infiltrating inflammatory cells in different pathologic settings contributes to organ and tumor angiogenesis. Here we demonstrate that IL-3 expands a subset of CD45+ circulating angiogenic cells clonally derived from the hemopoietic progenitors. Moreover, CD45+ cells exposed to IL-3 acquire arterial specification and contribute to the formation of vessels in vivo. Depletion of signal transducer and activator of transcription 5 (STAT5) provides evidence that IL-3–mediated cell expansion and arterial morphogenesis rely on STAT5 activation. In addition, by means of Tie2-transgenic mice, we demonstrate that STAT5 also regulates IL-3–induced expansion and arterial specification of bonemarrow–derived CD45+ cells. Thus, our data provide the first evidence that, in inflammatory microenvironments containing IL-3, angiogenic cells derived from hemopoietic precursors can act as adult vasculogenic cells. Moreover, the characterization of the signaling pathway regulating these events provides the rationale for therapeutically targeting STAT5 in these pathologic settings.
Rituximab efficacy and safety in adult splenectomy candidates with chronic immune thrombocytopenic purpura: results of a prospective multicenter phase 2 study
Authors: Godeau Bertrand , Porcher Raphael , Fain Olivier , Lefrère François , Fenaux Pierre , Cheze Stéphane , Vekhoff Anne , Chauveheid Marie-Paule , Stirnemann Jerôme , Galicier Lionel , Bourgeois Emmanuelle , Haiat Stéphanie , Varet Bruno , Leporrier Michel , Papo Thomas , Khellaf Mehdi , Michel Marc , Bierling Philippe 
Published: May 2008

Abstract
Whether rituximab could effectively and safely avoid splenectomy for adults with chronic immune thrombocytopenic purpura (ITP) remains unresolved. A multicenter, prospective, open-label, single-arm, phase 2 trial was conducted to assess rituximab safety and efficacy in adult splenectomy candidates with chronic ITP. Sixty patients with chronic (≥ 6 months) ITP and platelet counts less than 30 × 109/L received a weekly intravenous infusion of rituximab (375 mg/m2) for 4 weeks. All other ITP treatments were stopped. A good response was defined as a platelet count 50 × 109/L or more, with at least a doubling of the initial value at 1 and 2 years after the first rituximab infusion. Patients who required another treatment during follow up were considered nonresponders. Sixteen patients experienced transient side effects that necessitated treatment discontinuation for only 1. Good 1-year responses were obtained in 40% of the patients (24/60 [95% confidence interval: 28%-52%]). At 2 years, 33.3% (20/60 patients) had good responses and 6.7% (4/60) had sustained platelet counts of 30 × 109/L or more without treatment. Thirty-six (60%) patients failed to respond; 25 underwent splenectomy. Based on these results, rituximab was an apparently safe and effective splenectomy-avoiding option in some adults with chronic ITP. This trial is registered at http://clinicaltrials.gov as NCT00225875.
CPSP-tools – Exact and complete algorithms for high-throughput 3D lattice protein studies
Authors: Mann Martin , Will Sebastian , Backofen Rolf 
Published: May 2008

Abstract

Background
The principles of protein folding and evolution pose problems of very high inherent complexity. Often these problems are tackled using simplified protein models, e.g. lattice proteins. The CPSP-tools package provides programs to solve exactly and completely the problems typical of studies using 3D lattice protein models. Among the tasks addressed are the prediction of (all) globally optimal and/or suboptimal structures as well as sequence design and neutral network exploration.

Results
In contrast to stochastic approaches, which are not capable of answering many fundamental questions, our methods are based on fast, non-heuristic techniques. The resulting tools are designed for high-throughput studies of 3D-lattice proteins utilising the Hydrophobic-Polar (HP) model. The source bundle is freely available [1].

Conclusion
The CPSP-tools package is the first set of exact and complete methods for extensive, high-throughput studies of non-restricted 3D-lattice protein models. In particular, our package deals with cubic and face centered cubic (FCC) lattices.
Birth season and environmental influences on blood leucocyte and lymphocyte subpopulations in rural Gambian infants
Authors: Collinson Andrew C , Ngom Pa Tamba , Moore Sophie E , Morgan Gareth , Prentice Andrew M 
Published: May 2008

Abstract

Background
In rural Gambia, birth season predicts infection-related adult mortality, providing evidence that seasonal factors in early life may programme immune development. This study tested whether lymphocyte subpopulations assessed by automated full blood count and flow cytometry in cord blood and at 8, 16 and 52 weeks in rural Gambian infants (N = 138) are affected by birth season (DRY = Jan-Jun, harvest season, few infections; WET = Jul-Dec, hungry season, many infections), birth size or micronutrient status.

Results
Geometric mean cord and postnatal counts were higher in births occurring in the WET season with both season of birth and season of sampling effects. Absolute CD3+, CD8+, and CD56+ counts, were higher in WET season births, but absolute CD4+ counts were unaffected and percentage CD4+ counts were therefore lower. CD19+ counts showed no association with birth season but were associated with concurrent plasma zinc status. There were no other associations between subpopulation counts and micronutrient or anthropometric status.

Conclusion
These results demonstrate a seasonal influence on cell counts with a disproportionate effect on CD8+ and CD56+ relative to CD4+ cells. This seasonal difference was seen in cord blood (indicating an effect in utero) and subsequent samples, and is not explained by nutritional status. These findings are consistent with the hypothesis than an early environmental exposure can programme human immune development.
New evidence of a mitochondrial genetic background paradox: Impact of the J haplogroup on the A3243G mutation
Authors: Pierron Denis , Rocher Christophe , Amati-Bonneau Patricia , Reynier Pascal , Martin-Négrier Marie-Laure , Allouche Stéphane , Batandier Cécile , de Camaret Benedicte Mousson , Godinot Catherine , Rotig Agnes , Feldmann Delphine , Bellanne-Chantelot Christine , Arveiler Benoit , Pennarun Erwann , Rossignol Rodrigue , Crouzet Marc , Murail Pascal , Thoraval Didier , Letellier Thierry 
Published: May 2008

Abstract

Background
The A3243G mutation in the tRNALeu gene (UUR), is one of the most common pathogenic mitochondrial DNA (mtDNA) mutations in France, and is associated with highly variable and heterogeneous disease phenotypes. To define the relationships between the A3243G mutation and mtDNA backgrounds, we determined the haplogroup affiliation of 142 unrelated French patients – diagnosed as carriers of the A3243G mutation – by control-region sequencing and RFLP survey of their mtDNAs.

Results
The analysis revealed 111 different haplotypes encompassing all European haplogroups, indicating that the 3243 site might be a mutational hot spot. However, contrary to previous findings, we observed a statistically significant underepresentation of the A3243G mutation on haplogroup J in patients (p = 0.01, OR = 0.26, C.I. 95%: 0.08–0.83), suggesting that might be due to a strong negative selection at the embryo or germ line stages.

Conclusion
Thus, our study supports the existence of mutational hotspot on mtDNA and a "haplogroup J paradox," a haplogroup that may increase the expression of mtDNA pathogenic mutations, but also be beneficial in certain environmental contexts.
Anti-cyclic citrullinated peptide antibodies in primary Sjögren syndrome may be associated with non-erosive synovitis
Authors: Atzeni Fabiola , Sarzi-Puttini Piercarlo , Lama Nicola , Bonacci Eleonora , Bobbio-Pallavicini Francesca , Montecucco Carlomaurizio , Caporali Roberto 
Published: May 2008

Abstract
Introduction
The purpose of this study was to investigate the prevalence of cyclic citrullinated peptide antibodies (anti-CCP) in patients with primary Sjögren syndrome (pSS) and its correlation with clinical and laboratory data.

Methods
We analysed the clinical and serological data of 155 consecutive patients with pSS. Among these, 14 were excluded due to fulfillment of American College of Rheumatology criteria for rheumatoid arthritis (RA). So, 141 patients (27 males and 114 females; mean age 48 years, range 39 to 60) were clinically assessed for the presence of synovitis (objective swelling of one or more joints) and extra-glandular involvement. The anti-CCP antibodies were tested using a commercially available second-generation enzyme-linked immunosorbent assay. IgM rheumatoid factor (RF) was determined by nephelometry.

Results
Fourteen patients (9.9%) had moderate to high levels of anti-CCP, and 94 (66.7%) were positive for RF. Eighty-one (57.4%) showed extra-glandular involvement, and 44 (31.2%) had synovitis without any radiographic sign of erosion. There was a close correlation between the presence of anti-CCP and synovitis (P < 0.001) but no association between anti-CCP and extra-glandular involvement (P = 0.77). Multivariate analysis confirmed the association between anti-CCP and an increased prevalence of synovitis (prevalence odds ratio for positive versus negative anti-CCP status 7.611, 95% confidence interval 1.475 to 74.870; P = 0.010).

Conclusion
Only a minority of patients with pSS are anti-CCP-positive, which seems to be closely associated with the prevalence of synovitis. Anti-CCP positivity in patients with pSS therefore may be a predictor of future progress to RA or an expression of the inflammatory process of synovial tissue.
A phase 1 trial of nebulised heparin in acute lung injury
Authors: Dixon Barry , Santamaria John D , Campbell Duncan J 
Published: May 2008

Abstract
Introduction
Animal studies of acute lung injury (ALI) suggest nebulised heparin may limit damage from fibrin deposition in the alveolar space and microcirculation. No human studies have been undertaken to date. We assessed the feasibility, safety and potential anticoagulant effects of administration of nebulised heparin to patients with ALI.

Methods
An open label phase 1 trial of four escalating doses of nebulised heparin was performed. A total of 16 ventilated patients with ALI were studied. The first group was administered a total of 50,000 U/day, the second group 100,000 U/day, the third group 200,000 U/day and the fourth group 400,000 U/day. Assessments of lung function included the PaO2/FiO2 ratio, lung compliance and the alveolar dead space fraction. Monitoring of anticoagulation included the activated partial thromboplastin time (APTT) and the thrombin clotting time. Bronchoalveolar lavage fluid was collected and the prothrombin fragment and tissue plasminogen activator levels were assessed. Analysis of variance was used to compare the effects of dose.

Results
No serious adverse events occurred for any dose. The changes over time for the PaO2/FiO2 ratio, lung compliance and the alveolar dead space fraction levels were similar for all doses. A trend to increased APTT and thrombin clotting time levels was present with higher doses (P = 0.09 and P = 0.1, respectively). For the highest dose, the APTT reached 64 seconds; following cessation of nebulised heparin, the APTT fell to 39 seconds (P = 0.06). In bronchoalveolar lavage samples a trend to reduced prothrombin fragment levels was present with higher doses (P = 0.1), while tissue plasminogen activator levels were similar for all doses.

Conclusion
Administration of nebulised heparin to mechanically ventilated patients with ALI is feasible. Nebulised heparin was not associated with any serious adverse events, and at higher doses it increased APTT levels. Larger trials are required to further investigate the safety and efficacy of nebulised heparin. In these trials due consideration must be given to systemic anticoagulant effects.

Trial registration
Australian Clinical trials registry ACTRN12606000388516.