410 research outputs found

    NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign

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    This paper presents three-dimensional prognostic O<sub>3</sub> simulations with parameterized gas-phase photochemistry from the new NOGAPS-ALPHA middle atmosphere forecast model. We compare 5-day NOGAPS-ALPHA hindcasts of stratospheric O<sub>3</sub> with satellite and DC-8 aircraft measurements for two cases during the SOLVE II campaign: (1) the cold, isolated vortex during 11-16 January 2003; and (2) the rapidly developing stratospheric warming of 17-22 January 2003. In the first case we test three different photochemistry parameterizations. NOGAPS-ALPHA O<sub>3</sub> simulations using the NRL-CHEM2D parameterization give the best agreement with SAGE III and POAM III profile measurements. 5-day NOGAPS-ALPHA hindcasts of polar O<sub>3</sub> initialized with the NASA GEOS4 analyses produce better agreement with observations than do the operational ECMWF O<sub>3</sub> forecasts of case 1. For case 2, both NOGAPS-ALPHA and ECMWF 114-h forecasts of the split vortex structure in lower stratospheric O<sub>3</sub> on 21 January 2003 show comparable skill. Updated ECMWF O<sub>3</sub> forecasts of this event at hour 42 display marked improvement from the 114-h forecast; corresponding updated 42-hour NOGAPS-ALPHA prognostic O<sub>3</sub> fields initialized with the GEOS4 analyses do not improve significantly. When NOGAPS-ALPHA prognostic O<sub>3</sub> is initialized with the higher resolution ECMWF O<sub>3</sub> analyses, the NOGAPS-ALPHA 42-hour lower stratospheric O<sub>3</sub> fields closely match the operational 42-hour ECMWF O<sub>3</sub> forecast of the 21 January event. We find that stratospheric O<sub>3</sub> forecasts at high latitudes in winter can depend on both model initial conditions and the treatment of photochemistry over periods of 1-5 days. Overall, these results show that the new O<sub>3</sub> initialization, photochemistry parameterization, and spectral transport in the NOGAPS-ALPHA NWP model can provide reliable short-range stratospheric O<sub>3</sub> forecasts during Arctic winter

    Post-Einsteinian tests of linearized gravitation

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    The general relativistic treatment of gravitation can be extended by preserving the geometrical nature of the theory but modifying the form of the coupling between curvature and stress tensors. The gravitation constant is thus replaced by two running coupling constants which depend on scale and differ in the sectors of traceless and traced tensors. When calculated in the solar system in a linearized approximation, the metric is described by two gravitation potentials. This extends the parametrized post-Newtonian (PPN) phenomenological framework while allowing one to preserve compatibility with gravity tests performed in the solar system. Consequences of this extension are drawn here for phenomena correctly treated in the linear approximation. We obtain a Pioneer-like anomaly for probes with an eccentric motion as well as a range dependence of Eddington parameter Îł\gamma to be seen in light deflection experiments.Comment: 15 pages. Accepted version, to appear in Classical and Quantum Gravit

    Constraints on the Ultra High Energy Photon flux using inclined showers from the Haverah Park array

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    We describe a method to analyse inclined air showers produced by ultra high energy cosmic rays using an analytical description of the muon densities. We report the results obtained using data from inclined events (60^{\circ}<\theta<80^{\circ}) recorded by the Haverah Park shower detector for energies above 10^19 eV. Using mass independent knowledge of the UHECR spectrum obtained from vertical air shower measurements and comparing the expected horizontal shower rate to the reported measurements we show that above 10^19 eV less than 48 % of the primary cosmic rays can be photons at the 95 % confidence level and above 4 X 10^19 eV less than 50 % of the cosmic rays can be photonic at the same confidence level. These limits place important constraints on some models of the origin of ultra high-energy cosmic rays.Comment: 45 pages, 25 figure

    Electron, Muon, and Hadron Lateral Distributions Measured in Air-Showers by the KASCADE Experiment

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    Measurements of electron, muon, and hadron lateral distributions of extensive air showers as recorded by the KASCADE experiment are presented. The data cover the energy range from about 5x10^14 eV up to almost 10^17 eV and extend from the inner core region to distances of 200 m. The electron and muon distributions are corrected for mutual contaminations by taking into account the detector properties in the experiment. All distributions are well described by NKG-functions. The scale radii describing the electron and hadron data best are approx. 30 m and 10 m, respectively. We discuss the correlation between scale radii and `age' parameter as well as their dependence on shower size, zenith angle, and particle energy threshold.Comment: 28 pages, 14 figures, Accepted for publication in Astroparticle Physic

    Gene expression patterns vary in clonal cell cultures from Rett syndrome females with eight different MECP2 mutations

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    BACKGROUND: Females with the neurological disorder Rett syndrome are heterozygous for mutations in X-linked MECP2 that encodes methyl-CpG binding protein 2 (MeCP2) thought to act as a transcriptional repressor. To identify target genes for MeCP2 modulation, we studied global gene expression in single cell-derived wild-type and mutant MECP2 expressing fibroblast clones with four common mutations (R106W, R306C, 705delG, 1155del32) and in lymphoblastoid cell lines (LCLs) that included four mutant MeCP2 (T158M, 803delG, R168X and 1159del28) expressing, and five (1159del28, R106W, R255X, 803delG, 803delG) wild-type MeCP2 expressing lines. METHODS: Clonality and mutation status were verified by androgen receptor methylation assays for X-inactivation and by sequencing MECP2 transcripts. Expression studies were done with oligonucleotide microarrays (Affymetrix U95) and verified with real-time quantitative RT-PCR using Sybr Green. RESULTS: Expression of 49 transcripts was increased, and expression of 21 transcripts was decreased, in at least 3 of 4 mutant/wild-type fibroblast comparisons. Transcript levels of 11 genes, determined by quantitative RT-PCR, were highly correlated with the microarray data. Therefore, multiple additional clones from two Rett individuals were tested by RT-PCR only. Striking expression differences were found in both mutant and wildtype MeCP2 expressing clones. Comparing expression profiles of lymphoblastoid cell lines yielded 16 differentially expressed genes. CONCLUSIONS: MeCP2 deficiency does not lead to global deregulation of gene expression. Either MeCP2's in vivo function does not involve widespread transcriptional repression, or its function is redundant in cell types that also express other methyl-CpG binding proteins. Our data suggest that clonal fibroblast strains may show substantial inter-strain variation, making them a difficult and unstable resource for genome-wide expression profiling studies

    Transnational Investments of the Tunisian Diaspora: Trajectories, Skills Accumulation and Constraints

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    This chapter is based on recent empirical data on Tunisians living in Switzerland. It focuses on their migration pathways and experiences, and it examines their propensity to engage in entrepreneurial and business activities in their home country. Despite the hopes generated by the revolution of 2011, there are many people in Tunisia, especially young males from disadvantaged regions, who have not enjoyed the positive changes in employment opportunities and professional prospects. This has led them to them emigrate to Europe to ensure an income for themselves and their families back in Tunisia. An online survey accompanied by follow-up interviews enabled us to observe the experiences of Tunisian diaspora entrepreneurs and their current and potential future transnational business and investment activities. This chapter shows how the internationalization and accumulation of networks and skills by Tunisians, resulting from the multiple destinations they traversed before arriving to Switzerland, has influenced their professional capacities and their business and entrepreneurial projects in Tunisia. Tunisians feel a strong motivation to contribute to the development process in their home country, and they tend to invest and open businesses in their villages of origin. Several enablers and obstacles that influence their actions are observed. A number of policy recommendations based on the experiences and aspirations of these Tunisians are included in the conclusions

    The Coupled Model Intercomparison Project (CMIP)

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    The Coupled Model Intercomparison Project (CMIP) was established to study and intercompare climate simulations made with coupled ocean-atmosphere-cryosphere-land GCMs. There are two main phases (CMIP1 and CMIP2), which study, respectively, 1) the ability of models to simulate current climate, and 2) model simulations of climate change due to an idealized change in forcing (a 1% per year CO2 increase). Results from a number of CMIP projects were reported at the first CMIP Workshop held in Melbourne, Australia, in October 1998. Some recent advances in global coupled modeling related to CMIP were also reported. Presentations were based on preliminary unpublished results. Key outcomes from the workshop were that 1) many observed aspects of climate variability are simulated in global coupled models including the North Atlantic oscillation and its linkages to North Atlantic SSTs, El Niño-like events, and monsoon interannual variability; 2) the amplitude of both high- and low-frequency global mean surface temperature variability in many global coupled models is less than that observed, with the former due in part to simulated ENSO in the models being generally weaker than observed, and the latter likely to be at least partially due to the uncertainty in the estimates of past radiative forcing; 3) an El Niño-like pattern in the mean SST response with greater surface warming in the eastern equatorial Pacific than the western equatorial Pacific is found by a number of models in global warming climate change experiments, but other models have a more spatially uniform or even a La Niña-like, response; 4) flux adjustment, by definition, improves the simulation of mean present-day climate over oceans, does not guarantee a drift-free climate, but can produce a stable base state in some models to enable very long term (1000 yr and longer) integrations-in these models it does not appear to have a major effect on model processes or model responses to increasing CO2; and 5) recent multicentury integrations show that a stable surface climate can be attained without flux adjustment (though still with some systematic simulation errors)

    No evidence of enhanced oxidant production in blood obtained from patients with obstructive sleep apnea

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    <p>Abstract</p> <p>Background</p> <p>Obstructive sleep apnea syndrome (OSAS) is a recognized risk factor for cardiovascular morbidity and mortality, perhaps due to causative exacerbations of systemic oxidative stress. Putative oxidative stress related to numerous episodes of intermittent hypoxia, may be an oxidants chief driving force in OSAS patients.</p> <p>Methods</p> <p>We assessed the resting and n-formyl-methionyl-leucyl-phenylalanine (fMLP)- induced whole blood chemiluminescence (as a measure of oxidant production by polymorphonuclear leukocytes and monocytes), ferric reducing ability of plasma (FRAP) and H<sub>2</sub>O<sub>2 </sub>generation in the whole blood of 27 untreated OSAS patients, 22 subjects after a night of CPAP therapy and 11 controls without OSAS. All of them were matched to age, BMI (body mass index) and smoking habits. All parameters were measured before and after polysomnography-controlled sleep, individual results were obtained as a mean from duplicated experiments.</p> <p>Results</p> <p>No significant differences were distinguished between evening and morning blood chemiluminescence, H<sub>2</sub>O<sub>2 </sub>activity and FRAP within and between all three study groups.</p> <p>For instance patients with untreated OSAS had similar morning and evening resting whole blood chemiluminescence (2.3 +/- 2.2 vs. 2.4 +/- 2.2 [aU·10<sup>-4 </sup>phagocytes]), total light emission after stimulation with fMLP (1790 +/- 1371 vs. 1939 +/- 1532 [aU·s·10<sup>-4 </sup>phagocytes]), as well as FRAP after 3 min. plasma incubation (602 +/- 202 vs. 671 +/- 221 [uM]). Although, in the subgroup of 11 patients with severe OSAS (apnea/hypopnea index 58 +/- 18/h and oxygen desaturation index 55 +/- 19/h), the morning vs. evening resting chemiluminescence and total light emission after stimulation with fMLP observed a propensity to elevate 2.5 +/- 2.7 vs. 1.9 +/- 1.8 [aU·10<sup>-4 </sup>phagocytes] and 1778 +/- 1442 vs. 1503 +/- 1391 [aU·s·10<sup>-4 </sup>phagocytes], respectively, these did not attain statistical significance (p > 0.05).</p> <p>Conclusion</p> <p>Our investigation exposed no evidence in the overproduction of oxidants via circulating phagocytes, once considered a culprit in the oxidative stress of OSAS patients.</p

    A moral panic? The problematization of forced marriage in British newspapers

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    This paper examines the British media’s construction of forced marriage as an urgent social problem in a context where other forms of violence against women are not similarly problematised. A detailed analysis of four British newspapers over a ten-year period demonstrates that media reporting of forced marriage constitutes a moral panic in that it is constructed as a cultural problem that threatens Britain’s social order rather than as a specific form of violence against women. Thus, the current problematisation of forced marriage restricts discursive spaces for policy debates and hinders attempts to respond to this problem as part of broader efforts to tackle violence against women
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