2,733 research outputs found

    An influence functional for ultrasoft QCD

    Get PDF
    A real-time path integral for ultrasoft QCD is formulated. It exhibits a Feynman's influence functional. The statistical properties of the theory and the gauge symmetry are explicit. The correspondence is established with the alternative version, where a noise term enters a transport equation.Comment: 6 pages, no figure Strong Electroweak Matter (SEWM 2002), Heidelberg, 2-5 october 200

    Metastable States of Si<sup>-</sup> Observed in a Cryogenic Storage Ring

    No full text
    This thesis deals with the analysis of data from the Si- measurements performed in 2015 at the Cryogenic Storage Ring (CSR) located at the Max Planck Institute for Nuclear Physics. The Si- ion has four metastable fine-structure levels which decay to the ground state with certain radiative lifetimes. So far, none of these lifetimes have been determined experimentally. In the CSR experiments, the ion beam was sampled by two lasers at regular intervals and the photodetachment products were detected. To understand the physical processes behind the observed count rates, a model is constructed. The model equations are then solved to demonstrate that the count rates can be described by a sum of several exponential decay functions corresponding to the different radiative decays. For the analysis, a fit function is first applied to the measured data in order to derive values for the radiative lifetimes. The model itself is then used to try and verify the radiative lifetimes available from two theoretical calculations. It is found that at least one metastable state is very long-lived and at least two have short, but distinct, lifetimes. This contradicts one set of theoretical lifetimes; the results regarding the other ones remain inconclusive

    Evolution of a genus of gall wasp kleptoparasites

    Get PDF
    Kleptoparasites do not directly parasitize their hosts but instead steal food and resources, reducing host fitness. Like direct parasites, kleptoparasites can be highly dependent on their hosts such that their evolutionary histories may be linked. Here, we study the evolution of a kleptoparasitic wasp genus, Synergus (Hymenoptera: Cynipidae: Synergini), in relation to their hosts, oak gall wasps (Hymenoptera: Cynipidae: Cynipini). Ovipositing oak gall wasps induce the formation of galls on oaks (Fagaceae) that provide food and shelter to one or more developing gall wasps. Galls induced by different gall wasp species are diverse in size, shape, color, and location on the host tree, and tend to be specific to just one or a few oak tree species. Synergus, and other kleptoparasites, exploit galls by ovipositing into the developing gall and inducing the development of a secondary gall chamber. Synergus larva feed on the gall tissue, sometimes reducing food available to the oak gall wasp larva to the extent that the host dies. We ask how the ecology of gall wasps has affected the diversification of Synergus. We compare the topologies of Synergus and gall wasp phylogenetic trees and detect a significant signal of cophylogeny that appears limited to only a few interactions. We use traits of oak galls to describe the ecological niche for each Synergus species and reconstruct ecological traits of ancestral nodes. We find that ecological changes have been common across the evolutionary history of Synergus, with many transitions among different gall morphologies, gall site, and tree host

    EU-Turkey Accession Negotiations: Impact assessment of Chapter 10 on information society and media

    Get PDF
    In the past few years, Turkey has launched very important and ambitious reforms in the information society and media sector. Even more substantial changes are expected in 2009, after the new e-communications law has been approved at the end of 2008. Apart from the 49 expected pieces of secondary legislation foreseen to implement the new Law No 5809, Turkey has also planned important steps in the domain of spectrum policy, with licenses for WiMAX soon to be awarded. This report analyses the current state of advancement of Turkey\u2019s regulatory reform in this sector, and formulates suggestions for reform on the basis of a complex and articulated impact assessment exercise. Our final conclusion is that Turkey may profit significantly from a set of targeted reforms, aimed at solving existing problems that have been highlighted, i.a., by the European Commission and also by the recent ECTA Scorecard 2008

    Ultimate field-free molecular alignment by combined adiabatic-impulsive field design

    Full text link
    We show that a laser pulse designed as an adiabatic ramp followed by a kick allows one to reach a perfect postpulse molecular alignment, free of saturation. The mechanism is based on an optimized distribution of the energy between a weakly efficient but non saturating adiabatic ramp and an efficient but saturating impulsive field. Unprecedent degrees of alignment are predicted using state-of-the-art pulse shaping techniques and non-destructive field intensities. The scheme can be extended to reach high degrees of orientation of polar molecules using designed half-cycle pulses.Comment: 5 pages, 4 page

    Genetic heterogeneity of hepatitis E virus in Darfur, Sudan, and neighboring Chad.

    Get PDF
    The within-outbreak diversity of hepatitis E virus (HEV) was studied during the outbreak of hepatitis E that occurred in Sudan in 2004. Specimens were collected from internally displaced persons living in a Sudanese refugee camp and two camps implanted in Chad. A comparison of the sequences in the ORF2 region of 23 Sudanese isolates and five HEV samples from the two Chadian camps displayed a high similarity (>99.7%) to strains belonging to Genotype 1. But four isolates collected in one of the Chadian camps were close to Genotype 2. Circulation of divergent strains argues for possible multiple sources of infection

    Physical Study by Surface Characterizations of Sarin Sensor on the Basis of Chemically Functionalized Silicon Nanoribbon Field Effect Transistor

    Full text link
    Surface characterizations of an organophosphorus (OP) gas detector based on chemically functionalized silicon nanoribbon field-effect transistor (SiNR-FET) were performed by Kelvin Probe Force Microscopy (KPFM) and ToF-SIMS, and correlated with changes in the current-voltage characteristics of the devices. KPFM measurements on FETs allow (i) to investigate the contact potential difference (CPD) distribution of the polarized device as function of the gate voltage and the exposure to OP traces and, (ii) to analyze the CPD hysteresis associated to the presence of mobile ions on the surface. The CPD measured by KPFM on the silicon nanoribbon was corrected due to side capacitance effects in order to determine the real quantitative surface potential. Comparison with macroscopic Kelvin probe (KP) experiments on larger surfaces was carried out. These two approaches were quantitatively consistent. An important increase of the CPD values (between + 399 mV and + 302 mV) was observed after the OP sensor grafting, corresponding to a decrease of the work function, and a weaker variation after exposure to OP (between - 14 mV and - 61 mV) was measured. Molecular imaging by ToF-SIMS revealed OP presence after SiNR-FET exposure. The OP molecules were essentially localized on the Si-NR confirming effectiveness and selectivity of the OP sensor. A prototype was exposed to Sarin vapors and succeeded in the detection of low vapor concentrations (40 ppm).Comment: Paper and supporting information, J. Phys. Chem. C, 201

    Prevalence study of yaws in the Democratic Republic of Congo using the lot quality assurance sampling method.

    Get PDF
    BACKGROUND: Until the 1970s the prevalence of non-venereal trepanomatosis, including yaws, was greatly reduced after worldwide mass treatment. In 2005, cases were again reported in the Democratic Republic of the Congo. We carried out a survey to estimate the village-level prevalence of yaws in the region of Equator in the north of the country in order to define appropriate strategies to effectively treat the affected population. METHODOLOGY/PRINCIPAL FINDINGS: We designed a community-based survey using the Lot Quality Assurance Sampling method to classify the prevalence of active yaws in 14 groups of villages (lots). The classification into high, moderate, or low yaws prevalence corresponded to World Health Organization prevalence thresholds for identifying appropriate operational treatment strategies. Active yaws cases were defined by suggestive clinical signs and positive rapid plasma reagin and Treponema pallidum hemagglutination serological tests. The overall prevalence in the study area was 4.7% (95% confidence interval: 3.4-6.0). Two of 14 lots had high prevalence (>10%), three moderate prevalence (5-10%) and nine low prevalence (<5%.). CONCLUSIONS/SIGNIFICANCE: Although yaws is no longer a World Health Organization priority disease, the presence of yaws in a region where it was supposed to be eradicated demonstrates the importance of continued surveillance and control efforts. Yaws should remain a public health priority in countries where previously it was known to be endemic. The integration of sensitive surveillance systems together with free access to effective treatment is recommended. As a consequence of our study results, more than 16,000 people received free treatment against yaws

    ALICE Muon Trigger Performance

    Get PDF

    Field evaluation of two rapid diagnostic tests for Neisseria meningitidis serogroup A during the 2006 outbreak in Niger.

    Get PDF
    The Pastorex((R)) (BioRad) rapid agglutination test is one of the main rapid diagnostic tests (RDTs) for meningococcal disease currently in use in the "meningitis belt". Earlier evaluations, performed after heating and centrifugation of cerebrospinal fluid (CSF) samples, under good laboratory conditions, showed high sensitivity and specificity. However, during an epidemic, the test may be used without prior sample preparation. Recently a new, easy-to-use dipstick RDT for meningococcal disease detection on CSF was developed by the Centre de Recherche Médicale et Sanitaire in Niger and the Pasteur Institute in France. We estimate diagnostic accuracy in the field during the 2006 outbreak of Neisseria meningitidis serogroup A in Maradi, Niger, for the dipstick RDT and Pastorex((R)) on unprepared CSF, (a) by comparing each test's sensitivity and specificity with previously reported values; and (b) by comparing results for each test on paired samples, using McNemar's test. We also (c) estimate diagnostic accuracy of the dipstick RDT on diluted whole blood. We tested unprepared CSF and diluted whole blood from 126 patients with suspected meningococcal disease presenting at four health posts. (a) Pastorex((R)) sensitivity (69%; 95%CI 57-79) was significantly lower than found previously for prepared CSF samples [87% (81-91); or 88% (85-91)], as was specificity [81% (95%CI 68-91) vs 93% (90-95); or 93% (87-96)]. Sensitivity of the dipstick RDT [89% (95%CI 80-95)] was similar to previously reported values for ideal laboratory conditions [89% (84-93) and 94% (90-96)]. Specificity, at 62% (95%CI 48-75), was significantly lower than found previously [94% (92-96) and 97% (94-99)]. (b) McNemar's test for the dipstick RDT vs Pastorex((R)) was statistically significant (p<0.001). (c) The dipstick RDT did not perform satisfactorily on diluted whole blood (sensitivity 73%; specificity 57%).Sensitivity and specificity of Pastorex((R)) without prior CSF preparation were poorer than previously reported results from prepared samples; therefore we caution against using this test during an epidemic if sample preparation is not possible. For the dipstick RDT, sensitivity was similar to, while specificity was not as high as previously reported during a more stable context. Further studies are needed to evaluate its field performance, especially for different populations and other serogroups
    • …
    corecore