855 research outputs found

    Radiative corrections to muon decay in leading and next to leading approximation for electron spectrum

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    We have noted that the electron spectrum of muon decay in the leading logarithmic approximation calculated in two lowest orders of the perturbation theory in the paper of Berman (1958), can be reproduced by the parton language. This fact permits one to generalize the result to all orders of the perturbation theory using the structure function method.Comment: 4 pages, 1 figur

    Radiative proton-antiproton annihilation to a lepton pair

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    The annihilation of proton and antiproton to electron-positron pair, including radiative corrections due to the emission of virtual and real photons is considered. The results are generalized to leading and next-to leading approximations. The relevant distributions are derived and numerical applications are given in the kinematical range accessible to the PANDA experiment at the FAIR facility.Comment: 2 figure

    Development, evaluation and validation of a new instrument for measurement quality of life in the parents of children with chronic disease

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    <p>Abstract</p> <p>Background</p> <p>Childhood chronic disease may affect patients' and their family's functioning. Particularly parents, who play an important role in cooperation between patient and health care professionals, report impaired health - related quality of life (HRQOL). The aim of this study was development, evaluation and validation of a new instrument: Quality of Life in a Child's Chronic Disease Questionnaire (QLCCDQ). The questionnaire is addressed to parents of children with a chronic disease.</p> <p>Methods</p> <p>Study design included semi structured interview and qualitative study, which allowed to identify most troublesome problems. Following the results the questionnaire was developed, which consists of 15 questions and covers domains - emotions, patients -perceived symptoms, roles limitations. An observational study involving parents of asthma and diabetes children was conducted to assess the psychometric characteristics of the measure. Psychometric testing was based on the reliability of defined subscales, construct validity, reproducibility assessment, as well as comparison between stable/unstable disease stages and parents of healthy children.</p> <p>Results</p> <p>Most troublesome concerns for parents of child with chronic disease included emotional distress and feeling depressed due to child's disease, avoiding social interactions due to child's disease or symptoms. 98 parents of children with asthma or insulin - depended diabetes participated in the psychometric testing of QLCCDQ. Internal consistency reliability for the defined subscales ranged between 0.77 and 0.93. Reproducibility based on the weighted kappa coefficients showed expected level of agreement and was almost perfect in case of 8 questions, substantial for 5 questions and moderate for 2 questions. QLCCDQ demonstrated very good construct validity - all subscales showed statistically significant correlations ranging from 0.4 to 0.9. QLCCDQ scores differed significantly by clinical status - parents of children qualified as stable presented higher scores in most subscales in comparison to parents of children with unstable disease.</p> <p>Conclusions</p> <p>The QLCCDQ shows good internal consistency, test-retest reliability, and construct validity. The questionnaire may be useful in helping to understand the impact of chronic child's disease on parental perception of health outcomes.</p

    Improved Phase Space Treatment of Massive Multi-Particle Final States

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    In this paper the revised Kajantie-Byckling approach and improved phase space sampling techniques for the massive multi-particle final states are presented. The application of the developed procedures to the processes representative for LHC physics indicates the possibility of a substantial simplification of multi-particle phase space sampling while retaining a respectable weight variance reduction and unweighing efficiencies in the event generation process.Comment: Minor stilistic changes, submitted to EPJ

    Synthesis and Properties of High Tilted Antiferroelectric Esters with Partially Fluorinated Alkoxyalkoxy Terminal Chains

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    Novel chiral esters with partially fluorinated alkoxyalkoxy terminal chains are described. Their phase transition temperatures, enthalpies, and electrooptical properties are reported. A helical pitch in pure compounds and their mixtures based on selective reflection of light is also characterized

    Near threshold radiative 3π\pi production in e+e−e^+e^- annihilation

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    We consider the π+π−π0Îł\pi^+\pi^-\pi_0\gamma final state in electron-positron annihilation at cms energies not far from the threshold. Both initial and final state radiations of the hard photon is considered but without interference between them. The amplitude for the final state radiation is obtained by using the effective Wess-Zumino-Witten Lagrangian for pion-photon interactions valid for low energies. In real experiments energies are never such small that ρ\rho and ω\omega mesons would have negligible effect. So a phenomenological Breit-Wigner factor is introduced in the final state radiation amplitude to account for the vector mesons influence. Using radiative 3π\pi production amplitudes, a Monte Carlo event generator was developed which could be useful in experimental studies.Comment: 15 pages, Latex, 6 figures. Misprints corrected. Version to be published in JHE

    The effect of light intensity on the production of oat (Avena sativa L.) doubled haploids through oat × maize crosses

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    Oat haploid embryos were obtained by wide crossing with maize. The effect of light intensity during the growing period of donor plants (450 and 800 ”mol m−2 s−1) and in vitro cultures (20, 40, 70 and 110 ”mol m−2 s−1) was examined for the induction and development of oat DH lines. Oat florets (26008) from 32 genotypes were pollinated with maize and treated with 2,4-dichlorophenoxyacetic acid. All the tested genotypes formed more haploid embryos when donor plants were grown in a greenhouse (9.4%) compared to a growth chamber (6.1%). The light intensity of 110 ”mol m−2 s−1 during in vitro culture resulted in the highest percentage of embryo germination (38.9%), conversion into plants (36.4%) and DH line production (9.2%) when compared with lower light intensities (20, 40 and 70 ”mol m−2 s−1). The results show that the growth conditions of the donor plant and light intensity during in vitro culture can affect the development of haploid embryos. This fact may have an impact on oat breeding programs using oat × maize crosses

    Crustal influx, indentation, ductile thinning and gravity redistribution in a continental wedge: Building a Moldanubian mantled gneiss dome with underthrust Saxothuringian material (European Variscan belt)

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    27 p.International audience[1] The contribution of lateral forces, vertical load, gravity redistribution and erosion to the origin of mantled gneiss domes in internal zones of orogens remains debated. In the Orlica-Snieznik dome (Moldanubian zone, European Variscan belt), the polyphase tectono-metamorphic history is initially characterized by the development of subhorizontal fabrics associated with medium- to high-grade metamorphic conditions in different levels of the crust. It reflects the eastward influx of a Saxothuringian-type passive margin sequence below a TeplĂĄ-Barrandian upper plate. The ongoing influx of continental crust creates a thick felsic orogenic root with HP rocks and migmatitic orthogneiss. The orogenic wedge is subsequently indented by the eastern Brunia microcontinent producing a multiscale folding of the orogenic infrastructure. The resulting kilometre-scale folding is associated with the variable burial of the middle crust in synforms and the exhumation of the lower crust in antiforms. These localized vertical exchanges of material and heat are coeval with a larger crustal-scale folding of the whole infrastructure generating a general uplift of the dome. It is exemplified by increasing metamorphic conditions and younging of 40Ar/39Ar cooling ages toward the extruded migmatitic subdomes cored by HP rocks. The vertical growth of the dome induces exhumation by pure shear-dominated ductile thinning laterally evolving to non-coaxial detachment faulting, while erosion feeds the surrounding sedimentary basins. Modeling of the Bouguer anomaly grid is compatible with crustal-scale mass transfers between a dense superstructure and a lighter infrastructure. The model implies that the Moldanubian Orlica-Snieznik mantled gneiss dome derives from polyphase recycling of Saxothuringian material

    Event Generators for Bhabha Scattering

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    The results obtained by the "Event Generators for Bhabha Scattering" working group during the CERN Workshop "Physics at LEP2" (1994/1995) are presented.Comment: 70 pages, PostScript file. To appear in the Report of the Workshop on Physics at LEP2, G. Altarelli T. Sjostrand and F. Zwirner ed

    Radiative Correction to the Transferred Polarization in Elastic Electron-Proton Scattering

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    Model independent radiative correction to the recoil proton polarization for the elastic electron-proton scattering is calculated within method of electron structure functions. The explicit expressions for the recoil proton polarization are represented as a contraction of the electron structure and the hard part of the polarization dependent contribution into cross-section. The calculation of the hard part with first order radiative correction is performed. The obtained representation includes the leading radiative corrections in all orders of perturbation theory and the main part of the second order next-to-leading ones. Numerical calculations illustrate our analytical results.Comment: 14 pages, 4 figure
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