1,359 research outputs found

    Angular dependences in electroweak semi-inclusive leptoproduction

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    We present the leading order unpolarized and polarized cross sections in electroweak semi-inclusive deep inelastic leptoproduction. The azimuthal dependences in the cross section differential in the transverse momentum of the vector boson arise due to intrinsic transverse momenta of the quarks. However, the presented asymmetries are not suppressed by inverse powers of the hard scale. We discuss the different opportunities to measure specific asymmetries as offered by neutral compared to charged current processes and point out the optimal kinematical regions. The present and (proposed) future HERA collider experiments would be most suitable for measuring some of the asymmetries discussed here, especially in case of Lambda production.Comment: 10 pages, Revtex, 5 Postscript figures, uses aps.sty, epsfig.st

    Spin structure and longitudinal polarization of hyperon in e+e- annihilation at high energies

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    Longitudinal polarizations of different kinds of hyperons produced in e+e- annihilation at LEP I and LEP II energies in different event samples are calculated using two different pictures for the spin structure of hyperon: that drawn from polarized deep inelastic lepton-nucleon scattering data or that using SU(6) symmetric wave functions. The result shows that measurements of such polarizations should provide useful information to the question of which picture is more suitable in describing the spin effects in the fragmentation processes.Comment: 26 pages with 10 figures. Submitted to Phys. Rev.

    Spin alignment of vector meson in e+e- annihilation at Z0 pole

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    We calculate the spin density matrix of the vector meson produced in e+e- annihilation at Z^0 pole. We show that the data imply a significant polarization for the antiquark which is created in the fragmentation process of the polarized initial quark and combines with the fragmenting quark to form the vector meson. The direction of polarization is opposite to that of the fragmenting quark and the magnitude is of the order of 0.5. A qualitative explanation of this result based on the LUND string fragmentation model is given.Comment: 15 pages, 2 fgiures; submitted to Phys. Rev.

    RF Analysis of a Sub-GHz InP-Based 1550 nm Monolithic Mode-Locked Laser Chip

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    We report a monolithic sub-GHz repetition rate mode-locked laser with record low pulse-to-pulse RMS timing jitter of 3.65 ps in the passive mode locking regime. We analyse the optical pulse generation in passive and hybrid mode-locking operating regimes, finding narrower RF tone linewidth in the passive regime, attributed to the improved contact structure of the gain sections. The noise performance is also characterized in passive and hybrid regimes, showing RMS integrated timing jitter of approximately 600 fs. For hybrid modelocking, the repetition rate can be varied over a large range from 880 to 990 MHz. We observe broad pulse widths of few hundred picoseconds attributed to the (long folded) waveguide architecture and on-chip multimode interference mirrors. This device subjects a stand-alone, ultra-compact, mode-locking based clock source to realize frequency synthesizers operating over a frequency range from sub-GHz up to approximately 15 GHz

    ProblĂ©matique D’Evacuation Des DĂ©chets MĂ©nagers Dans La Cite De Bumba: « Cas Du Quartier Nzongo : Du 1er Janvier Au 30 Avril 2019 »

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    face aux impacts nĂ©gatifs des dĂ©chets mĂ©nagers sur la qualitĂ© de l’environnement et sur la santĂ© publique ; la gestion durable des dĂ©chets mĂ©nagers est devenue un sujet d’actualitĂ© et nombreuses Ă©tudes y menĂ©es mettent en Ă©vidence divers risques environnementaux et sanitaires pour les populations le quartier Nzongo, notre milieu d’étude dans la citĂ© de Bumba abandonne ses dĂ©chets mĂ©nagers sur des terrains vagues et dans des trous se trouvant dans les habitations. L’insalubritĂ© constatĂ©e dans ce quartier avec des consĂ©quences nĂ©gatives sur la santĂ© de la population a attirĂ© notre attention afin de traiter de la problĂ©matique d’évacuation des dĂ©chets mĂ©nagers dans la citĂ© de Bumba ; cas du quartier Nzongo

    Les Albinos Face Au Développement Economique Du Territoire De Bumba « Cas De La Cité De Bumba »

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    l’albinisme est une affection autosomique rĂ©cessive due Ă  l’absence de mĂ©lanine dans  la peau, les  cheveux et les jeux. Les gens qui souffrent   de cette affection sont des albinos, souvent victimes des sacrifices humains d’assassinat voire d’enlĂšvement pour des fins magiques.  Etant marginalisĂ©s, leurs capacitĂ©s restent inexploitĂ©es dans le menu du dĂ©veloppement leur identification intĂ©gration  et leur promotion Ă©ducative seraient  des pistes de sortie du comportement  discriminatoire  leur affiché  afin d’atteindre  les  objectifs  du  millĂ©naire  pour le dĂ©veloppement  qui stipule « amĂ©lioration  de la santé  sous toutes ces formes  et  rĂ©duire par  consĂ©quent ; l’extrĂȘme pauvreté »

    Systematic analysis of the polyphenol metabolome using the Phenol-Explorer database

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    SCOPE: The Phenol-Explorer web database details 383 polyphenol metabolites identified in human and animal biofluids from 221 publications. Here we exploit these data to characterize and visualize the polyphenol metabolome, the set of all metabolites derived from phenolic food components. METHODS AND RESULTS: Qualitative and quantitative data on 383 polyphenol metabolites as described in 424 human and animal intervention studies were systematically analyzed. Of these metabolites, 301 were identified without prior enzymatic hydrolysis of biofluids, and included glucuronide and sulfate esters, glycosides, aglycones, and O-methyl ethers. Around one third of these compounds are also known as food constituents and corresponded to polyphenols absorbed without further metabolism. Many ring-cleavage metabolites formed by gut microbiota were noted, mostly derived from hydroxycinnamates, flavanols and flavonols. Median maximum plasma concentrations (Cmax ) of all human metabolites were 0.09 ÎŒM and 0.32 ÎŒM when consumed from foods or dietary supplements respectively. Median time to reach maximum plasma concentration in humans (Tmax ) was 2.18 h. CONCLUSION: These data show the complexity of the polyphenol metabolome and the need to take into account biotransformations to understand in vivo bioactivities and the role of dietary polyphenols in health and disease. This article is protected by copyright. All rights reserved

    Structure and Function of a Mycobacterial NHEJ DNA Repair Polymerase

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    Non homologous end-joining (NHEJ)-mediated repair of DNA double-strand breaks in prokaryotes requires Ku and a specific multidomain DNA ligase (LigD). We present crystal structures of the primase/polymerisation domain (PolDom) of Mycobacterium tuberculosis LigD, alone and complexed with nucleotides. The PolDom structure combines the general fold of the archaeo-eukaryotic primase (AEP) superfamily with additional loops and domains that together form a deep cleft on the surface, likely used for DNA binding. Enzymatic analysis indicates that the PolDom of LigD, even in the absence of accessory domains and Ku proteins, has the potential to recognise DNA end-joining intermediates. Strikingly, one of the main signals for the specific and efficient binding of PolDom to DNA is the presence of a 5'-phosphate group, located at the single/double-stranded junction at both gapped and 3'-protruding DNA molecules. Although structurally unrelated, Pol lambda and Pol mu, the two eukaryotic DNA polymerases involved in NHEJ, are endowed with a similar capacity to bind a 5'-phosphate group. Other properties that are beneficial for NHEJ, such as the ability to generate template distortions and realignments of the primer, displayed by Pol lambda and Pol mu, are shared by the PolDom of bacterial LigD. In addition, PolDom can perform non-mutagenic translesion synthesis on termini containing modified bases. Significantly, ribonucleotide insertion appears to be a recurrent theme associated with NHEJ, maximised in this case by the deployment of a dedicated primase, although its in vivo relevance is unknown

    Phenol-Explorer 2.0: a major update of the Phenol-Explorer database integrating data on polyphenol metabolism and pharmacokinetics in humans and experimental animals

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    Phenol-Explorer, launched in 2009, is the only comprehensive web-based database on the content in foods of polyphenols, a major class of food bioactives that receive considerable attention due to their role in the prevention of diseases. Polyphenols are rarely absorbed and excreted in their ingested forms, but extensively metabolized in the body, and until now, no database has allowed the recall of identities and concentrations of polyphenol metabolites in biofluids after the consumption of polyphenol-rich sources. Knowledge of these metabolites is essential in the planning of experiments whose aim is to elucidate the effects of polyphenols on health. Release 2.0 is the first major update of the database, allowing the rapid retrieval of data on the biotransformations and pharmacokinetics of dietary polyphenols. Data on 375 polyphenol metabolites identified in urine and plasma were collected from 236 peer-reviewed publications on polyphenol metabolism in humans and experimental animals and added to the database by means of an extended relational design. Pharmacokinetic parameters have been collected and can be retrieved in both tabular and graphical form. The web interface has been enhanced and now allows the filtering of information according to various criteria. Phenol-Explorer 2.0, which will be periodically updated, should prove to be an even more useful and capable resource for polyphenol scientists because bioactivities and health effects of polyphenols are dependent on the nature and concentrations of metabolites reaching the target tissues. The Phenol-Explorer database is publicly available and can be found online at http://www.phenol-explorer.eu. Database URL: http://www.phenol-explorer.eu

    Vitamin D Status and Longitudinal Changes in Body Composition in Patients with Chronic Obstructive Pulmonary Disease – A Prospective Observational Study

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    Maria Minter,1,2 Jenny van Odijk,1 Hanna Augustin,1 Felipe VC Machado,3,4 Frits ME Franssen,5,6 Martijn A Spruit,5,6 Lowie EGW Vanfleteren1,5 1Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, 405 30, Sweden; 2Department of Lung Medicine, Angered Hospital, SV Hospital Group, Angered, 424 22, Sweden; 3Rehabilitation Research Center (REVAL), Faculty of Rehabilitation Sciences, Hasselt University, Diepenbeek, Belgium; 4Biomedical Research Institute (BIOMED), Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium; 5Department of Research and Development, Ciro, Horn, the Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands; 6Department of Respiratory Medicine, School of Nutrition and Translational Research in Metabolism (NUTRIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University Medical Centre+, Maastricht, the NetherlandsCorrespondence: Maria Minter, Department of Lung Medicine, Angered Hospital, SV Hospital Group, Angered, 424 22, Sweden, Email [email protected]: Alterations in body weight and composition are common in patients with chronic obstructive pulmonary disease (COPD) and are independent predictors for morbidity and mortality. Low vitamin D status is also more prevalent in patients with COPD compared to controls and has been related to lower lung function, muscle atrophy and impaired musculoskeletal function. This study aimed to evaluate the association between vitamin D levels and status with body composition (BC), as well as with its changes over time.Patients and Methods: Patients with COPD and controls without COPD, participating in the Individualized COPD Evaluation in relation to Ageing (ICE‐Age) study, a prospective observational study, were included. Plasma 25-hydroxyvitamin D (25(OH)D) was measured at baseline and BC was measured by dual‐energy X‐ray absorptiometry scan, at baseline and after two years of follow-up. Multiple linear regression analyses were performed to assess the relationships between 25(OH)D (nmol/l) and longitudinal changes in BMI, fat-free mass index (FFMI), fat mas index (FMI) and bone mineral density (BMD).Results: A total of 192 patients with COPD (57% males, mean ± SD age, 62 ± 7, FEV1, 49 ± 16% predicted) and 199 controls (45% males, mean ± SD age 61 ± 7) were included in this study. Vitamin D levels were significantly lower in patients with COPD (64 ± 26 nmol/L, 95% CI 60– 68 nmol/L versus 75 ± 25 nmol/L, 95% CI 72– 79 nmol/L) compared to controls. Both patients and controls presented a significant decline in FFMI and T-score hip, but vitamin D level or status did not determine differences in BC or changes in BC over time in either COPD or controls.Conclusion: Vitamin D status was not associated with BC or longitudinal changes in BC. However, vitamin D insufficiency and low BMD were more prevalent in patients with COPD compared to controls.Keywords: chronic obstructive pulmonary disease, body composition, vitamin D, longitudinal changes, fat-free mass, bone mineral densit
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