Radiative corrections to neutrino deep inelastic scattering revisited

International Nuclear Information System (INIS)

Arbuzov, Andrej B.; Bardin, Dmitry Yu.; Kalinovskaya, Lidia V.

2005-01-01

Radiative corrections to neutrino deep inelastic scattering are revisited. One-loop electroweak corrections are re-calculated within the automatic SANC system. Terms with mass singularities are treated including higher order leading logarithmic corrections. Scheme dependence of corrections due to weak interactions is investigated. The results are implemented into the data analysis of the NOMAD experiment. The present theoretical accuracy in description of the process is discussed

One loop electro-weak radiative corrections in the standard model

International Nuclear Information System (INIS)

Kalyniak, P.; Sundaresan, M.K.

1987-01-01

This paper reports on the effect of radiative corrections in the standard model. A sensitive test of the three gauge boson vertices is expected to come from the work in LEPII in which the reaction e + e - → W + W - can occur. Two calculations of radiative corrections to the reaction e + e - → W + W - exist at present. The results of the calculations although very similar disagree with one another as to the actual magnitude of the correction. Some of the reasons for the disagreement are understood. However, due to the reasons mentioned below, another look must be taken at these lengthy calculations to resolve the differences between the two previous calculations. This is what is being done in the present work. There are a number of reasons why we must take another look at the calculation of the radiative corrections. The previous calculations were carried out before the UA1, UA2 data on W and Z bosons were obtained. Experimental groups require a computer program which can readily calculate the radiative corrections ab initio for various experimental conditions. The normalization of sin 2 θ w in the previous calculations was done in a way which is not convenient for use in the experimental work. It would be desirable to have the analytical expressions for the corrections available so that the renormalization scheme dependence of the corrections could be studied

Electroweak radiative corrections to parity-violating electroexcitation of the Δ

International Nuclear Information System (INIS)

Zhu Shilin; Sacco, G.; Maekawa, C.M.; Holstein, B. R.; Ramsey-Musolf, M.J.

2002-01-01

We analyze the degree to which parity-violating (PV) electroexcitation of the Δ(1232) resonance may be used to extract the weak neutral axial vector transition form factors. We find that the axial vector electroweak radiative corrections are large and theoretically uncertain, thereby modifying the nominal interpretation of the PV asymmetry in terms of the weak neutral form factors. We also show that, in contrast with the situation for elastic electron scattering, the axial N→Δ PV asymmetry does not vanish at the photon point as a consequence of a new term entering the radiative corrections. We argue that an experimental determination of these radiative corrections would be of interest for hadron structure theory, possibly shedding light on the violation of Hara's theorem in weak, radiative hyperon decays

Radiation Emitting Product Corrective Actions and Recalls

Data.gov (United States)

U.S. Department of Health & Human Services — This database provides descriptions of radiation-emitting products that have been recalled under an approved corrective action plan to remove defective and...

QED radiative corrections to the pionium life time

International Nuclear Information System (INIS)

Kuraev, Eh.A.

1997-01-01

The lowest order QED radiative corrections to the cross section of the recharged process of transition of two neutral ones and to the pionium lifetime are calculated in frame of scalar QED. It is argued that the ultraviolet cut-off of the loop momentum is to be chosen of order of ρ-meson mass. This fact permits to perform the calculation in frames of Effective Chiral Lagrangian theory with vector-meson dominance. The Coulomb factor corresponding to interaction in the initial state, shown, is to be removed to avoid the double counting. Resulting value of the radiative correction to the pionium lifetime is 0.25%

Generalized radiative corrections for hadronic targets

International Nuclear Information System (INIS)

Calan, C. de; Navelet, H.; Picard, J.

1990-02-01

Besides the radiative corrections theory at the order α 2 for reactions involving an arbitrary number of particles, this report gives the complete formula for the correction factor δ in dσ = dσ Born (1 + δ). The only approximation made here - unavoidable in this formulation - is to assume that the Born amplitude can be factorized. This calculation is valid for spin zero bosons. In the 1/2 fermion case, an extra contribution appears which has been analytically computed using a minor approximation. Special care has been devoted to the 1/v divergence of the amplitude near thresholds [fr

Nearly degenerate neutrinos, supersymmetry and radiative corrections

International Nuclear Information System (INIS)

Casas, J.A.; Espinosa, J.R.; Ibarra, A.; Navarro, I.

2000-01-01

If neutrinos are to play a relevant cosmological role, they must be essentially degenerate with a mass matrix of the bimaximal mixing type. We study this scenario in the MSSM framework, finding that if neutrino masses are produced by a see-saw mechanism, the radiative corrections give rise to mass splittings and mixing angles that can accommodate the atmospheric and the (large angle MSW) solar neutrino oscillations. This provides a natural origin for the Δm 2 sol 2 atm hierarchy. On the other hand, the vacuum oscillation solution to the solar neutrino problem is always excluded. We discuss also in the SUSY scenario other possible effects of radiative corrections involving the new neutrino Yukawa couplings, including implications for triviality limits on the Majorana mass, the infrared fixed point value of the top Yukawa coupling, and gauge coupling and bottom-tau unification

Radiative corrections to fermion matter and nontopological solitons

International Nuclear Information System (INIS)

Perry, R.J.

1984-01-01

This thesis addresses the effects of one loop radiative corrections to fermion matter and nontopological solitons. The effective action formalism is employed to explore the effects of these corrections on the ground state energy and scalar field expectation value of a system containing valence fermions, which are introduced using a chemical potential. This formalism is discussed extensively, and detailed calculations are presented for the Friedberg-Lee model. The techniques illustrated can be used in any renormalizable field theory and can be extended to include higher order quantum corrections

Single-loop renormalizations and properties of radiative corrections in the Fried-Yennie gauge

International Nuclear Information System (INIS)

Karshenboim, S.G.; Shelyuto, V.A.; Eides, M.I.

1988-01-01

Single-loop radiative corrections are studied in the Fried-Yennie gauge. It is shown that in this gauge the usual subtraction procedure on the mass shell does not require introduction of an infrared photon mass. The behavior of the diagrams containing radiative corrections near the mass shell is investigated, and it is shown that in the Fried-Yennie gauge this behavior is softer than in any other gauge and softer than the behavior of the corresponding graphs without radiative corrections

Radiative corrections to Higgs production from Z decay

International Nuclear Information System (INIS)

Kniehl, B.A.

1992-02-01

Full one-loop radiative corrections to the Bjorken process, Z → H fanti f, are calculated within the standard model. These corrections are used to refine the lower bound on the Higgs-boson mass coming from direct experimental searches at LEP 1 and SLC. It is demonstrated that loop effects can be reduced to a minimal level when the Born result is parametrized in terms of the Fermi constant. (orig.)

QED radiative corrections to impact factors

International Nuclear Information System (INIS)

Kuraev, E.A.; Lipatov, L.N.; Shishkina, T.V.

2001-01-01

We consider radiative corrections to the electron and photon impact factors. The generalized eikonal representation for the e + e - scattering amplitude at high energies and fixed momentum transfers is violated by nonplanar diagrams. An additional contribution to the two-loop approximation appears from the Bethe-Heitler mechanism of fermion pair production with the identity of the fermions in the final state taken into account. The violation of the generalized eikonal representation is also related to the charge parity conservation in QED. A one-loop correction to the photon impact factor for small virtualities of the exchanged photon is obtained using the known results for the cross section of the e + e - production during photon-nuclei interactions

QED radiative corrections in exclusive ρ0 leptoproduction

International Nuclear Information System (INIS)

Kurek, K.

1996-09-01

A semi-analytical approach to the model independent calculation of radiative corrections for exclusive ρ 0 meson leptoproduction (i.e. electron and muon scattering experiments) is presented. The corrections to ρ 0 production at large Q 2 as well as to ρ 0 photoproduction are studied in detail. The numerical results are calculated for two different experimental analyses: NMC (muoproduction at large Q 2 ) and ZEUS at HERA (quasi-real photoproduction). It is shown that the corrections are 2-5% for NMC and below 2% for the ZEUS measurement. The application of the presented approach to other vector meson production is straightforward. (orig.)

Radiation protection: A correction

International Nuclear Information System (INIS)

1972-01-01

An error in translation inadvertently distorted the sense of a paragraph in the article entitled 'Ecological Aspects of Radiation Protection', by Dr. P. Recht, which appeared in the Bulletin, Volume 14, No. 2 earlier this year. In the English text the error appears on Page 28, second paragraph, which reads, as published: 'An instance familiar to radiation protection specialists, which has since come to be regarded as a classic illustration of this approach, is the accidental release at the Windscale nuclear centre in the north of England.' In the French original of this text no reference was made, or intended, to the accidental release which took place in 1957; the reference was to the study of the critical population group exposed to routine releases from the centre, as the footnote made clear. A more correct translation of the relevant sentence reads: 'A classic example of this approach, well-known to radiation protection specialists, is that of releases from the Windscale nuclear centre, in the north of England.' A second error appeared in the footnote already referred to. In all languages, the critical population group studied in respect of the Windscale releases is named as that of Cornwall; the reference should be, of course, to that part of the population of Wales who eat laver bread. (author)

Dislocations and radiation damage in {alpha}-uranium; Dislocations et effets des radiations dans l'uranium {alpha}

Energy Technology Data Exchange (ETDEWEB)

Leteurtre, J [Commissariat a l' Energie Atomique, 92 - Fontenay-Aux-Roses (France). Centre d' Etudes Nucleaires

1968-07-01

Dislocations in {alpha}-uranium were studied by electron microscopy. Electropolishing of thin foils was performed at low temperature (-110 deg. C) to prevent oxidation. Burgers vectors of twins dislocations are defined. Interactions between slip and twinning are studied from both experimental and theoretical point of view. Samples irradiated at several burn-up were examined. In order to explain our micrographic results, and also all information gathered in literature about radiation damage in {alpha}-uranium, a coherent model is propound for the fission particles effects. We analyse the influences of parameters: temperature, dislocation density, impurity content. The number of point defects created by one initial fission is determined for pure and annealed metal. The importance of the self-anneal which occurs immediately in each displacement spike, and the anneal due to a new fission on the damage resulting from a previous fission, are estimated. The focussing distance in [100] direction is found to be about 1000 Angstrom, at 4 deg. K. (author) [French] Ce travail est une etude par microscopie electronique des dislocations induites dans l'uranium {alpha}, soit par deformation plastique, soit par irradiation. Une methode de preparation des lames minces a basse temperature (-110 deg. C) a ete mise au point. Les vecteurs de Burgers des diverses dislocations de macles de ce metal ont ete definis. Les interactions glissements- maclages sont etudiees experimentalement et theoriquement. Des echantillons irradies a divers taux de combustion ont ete examines. Pour expliquer nos resultats micrographiques, et aussi l'ensemble des informations recueillies dans la litterature concernant l'endommagement par irradiation de l'uranium-{alpha}, nous proposons un modele coherent de l'effet des fragments de fission dans ce metal. L'influence des parametres: temperature, densite de dislocations, impuretes est analysee. Le nombre de defauts ponctuels crees par une fission dans du metal

Radiative corrections to the masses of supersymmetric Higgs bosons

International Nuclear Information System (INIS)

Ellis, J.; Zwirner, F.

1991-01-01

The lightest neutral Higgs boson in the minimal supersymmetric extension of the standard model has a tree-level mass less than that of the Z 0 . We calculate radiative corrections to its mass and to that of the heavier CP-even neutral Higgs boson. We find large corrections that increase with the top quark and squark masses, and vary with the ratio of vacuum expectation values v 2 /v 1 . These radiative corrections can be as large as O(100) GeV, and have the effect of (i) invalidating lower bounds on v 2 /v 1 inferred from unsuccessful Higgs searches at LEP I, (ii) in many cases, increasing the mass of the lighter CP-even Higgs boson beyond m z , (iii) often, increasing the mass of the heavier CP-even Higgs boson beyond the LEP reach, into a range more accessible to the LHC or SSC. (orig.)

Calculation and measurement of radiation corrections for plasmon resonances in nanoparticles

Science.gov (United States)

Hung, L.; Lee, S. Y.; McGovern, O.; Rabin, O.; Mayergoyz, I.

2013-08-01

The problem of plasmon resonances in metallic nanoparticles can be formulated as an eigenvalue problem under the condition that the wavelengths of the incident radiation are much larger than the particle dimensions. As the nanoparticle size increases, the quasistatic condition is no longer valid. For this reason, the accuracy of the electrostatic approximation may be compromised and appropriate radiation corrections for the calculation of resonance permittivities and resonance wavelengths are needed. In this paper, we present the radiation corrections in the framework of the eigenvalue method for plasmon mode analysis and demonstrate that the computational results accurately match analytical solutions (for nanospheres) and experimental data (for nanorings and nanocubes). We also demonstrate that the optical spectra of silver nanocube suspensions can be fully assigned to dipole-type resonance modes when radiation corrections are introduced. Finally, our method is used to predict the resonance wavelengths for face-to-face silver nanocube dimers on glass substrates. These results may be useful for the indirect measurements of the gaps in the dimers from extinction cross-section observations.

Quantum Corrected Non-Thermal Radiation Spectrum from the Tunnelling Mechanism

Directory of Open Access Journals (Sweden)

Subenoy Chakraborty

2015-06-01

Full Text Available The tunnelling mechanism is today considered a popular and widely used method in describing Hawking radiation. However, in relation to black hole (BH emission, this mechanism is mostly used to obtain the Hawking temperature by comparing the probability of emission of an outgoing particle with the Boltzmann factor. On the other hand, Banerjee and Majhi reformulated the tunnelling framework deriving a black body spectrum through the density matrix for the outgoing modes for both the Bose-Einstein distribution and the Fermi-Dirac distribution. In contrast, Parikh and Wilczek introduced a correction term performing an exact calculation of the action for a tunnelling spherically symmetric particle and, as a result, the probability of emission of an outgoing particle corresponds to a non-strictly thermal radiation spectrum. Recently, one of us (C. Corda introduced a BH effective state and was able to obtain a non-strictly black body spectrum from the tunnelling mechanism corresponding to the probability of emission of an outgoing particle found by Parikh and Wilczek. The present work introduces the quantum corrected effective temperature and the corresponding quantum corrected effective metric is written using Hawking’s periodicity arguments. Thus, we obtain further corrections to the non-strictly thermal BH radiation spectrum as the final distributions take into account both the BH dynamical geometry during the emission of the particle and the quantum corrections to the semiclassical Hawking temperature.

Dématérialisation des corrections. : Quels changements dans la conception d'une épreuve d'évaluation ?

OpenAIRE

Capelle , Camille

2011-01-01

International audience; Notre contribution concerne l'intégration de technologies de dématérialisation de copies d'examen dans les pratiques de correction à l'Université. Ces technologies consistent à numériser les copies après une épreuve pour permettre une correction instrumentée sur une plateforme web dédiée. Doctorante CIFRE au sein de la société NEOPTEC, conceptrice du dispositif de dématérialisation des copies, l'approche par l'observation participante me permet de collecter, au moyen d...

Standard model treatment of the radiative corrections to the neutron β-decay

International Nuclear Information System (INIS)

Bunatyan, G.G.

2003-01-01

Starting with the basic Lagrangian of the Standard Model, the radiative corrections to the neutron β-decay are acquired. The electroweak interactions are consistently taken into consideration amenably to the Weinberg-Salam theory. The effect of the strong quark-quark interactions on the neutron β-decay is parametrized by introducing the nucleon electromagnetic form factors and the weak nucleon transition current specified by the form factors g V , g A , ... The radiative corrections to the total decay probability W and to the asymmetry coefficient of the momentum distribution A are obtained to constitute δW ∼ 8.7 %, δA ∼ -2 %. The contribution to the radiative corrections due to allowance for the nucleon form factors and the nucleon excited states amounts up to a few per cent of the whole value of the radiative corrections. The ambiguity in description of the nucleon compositeness is surely what causes the uncertainties ∼ 0.1 % in evaluation of the neutron β-decay characteristics. For now, this puts bounds to the precision attainable in obtaining the element V ud of the CKM matrix and the g V , g A , ... values from experimental data processing

Dosimetry techniques of thermal neutrons and {gamma} radiation in reactor cores; Techniques de dosimetrie des neutrons thermiques et du rayonnement {gamma} dans les piles

Energy Technology Data Exchange (ETDEWEB)

Sutton, J; Draganic, I; Hering, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

Chemical studies under radiation done in the reactor cores require to be followed by dosimetry. When the irradiations are done in the reflector, one can limit to the measure of the {gamma} and the neutron radiation. For the dosimetry of the {gamma} radiation, a dosimeter of ferrous sulfate is convenient until doses of about 10{sup 6} rep. The use of aired oxalic acid solutions permits to reach 10{sup 7} rep. The dosimetry of thermal neutrons has been made with solutions of cobalt sulphate or paper filter impregnated with this salt. The total chemical effect of the {gamma} and of the slow neutrons radiation is obtained with solutions of ferrous sulfate added with lithium sulphate. (M.B.) [French] Les etudes de chimie sous radiation faites dans les piles exigent d'etre suivies par dosimetrie. Lorsque les irradiations sont effectues dans le reflecteur, on peut se limiter a doser le rayonnement {gamma} et les neutrons. Pour la dosimetrie du rayonnement {gamma}, un dosimetre a sulfate ferreux convient jusqu'a des doses d'environ 10{sup 6} rep. L'emploi de solutions aerees d'acide oxalique permet d'atteindre 10{sup 7} rep. La dosimetrie des neutrons thermiques a ete faite avec des solutions de sulfate de cotalt ou du papier filtre impregne de ce sel. L'effet chimique total du rayonnement {gamma} et des neutrons lents est obtenu avec des solutions de sulfate ferreux additionne de sulfate de lithium. (M.B.)

Dislocations and radiation damage in {alpha}-uranium; Dislocations et effets des radiations dans l'uranium {alpha}

Energy Technology Data Exchange (ETDEWEB)

Leteurtre, J. [Commissariat a l' Energie Atomique, 92 - Fontenay-Aux-Roses (France). Centre d' Etudes Nucleaires

1968-07-01

Dislocations in {alpha}-uranium were studied by electron microscopy. Electropolishing of thin foils was performed at low temperature (-110 deg. C) to prevent oxidation. Burgers vectors of twins dislocations are defined. Interactions between slip and twinning are studied from both experimental and theoretical point of view. Samples irradiated at several burn-up were examined. In order to explain our micrographic results, and also all information gathered in literature about radiation damage in {alpha}-uranium, a coherent model is propound for the fission particles effects. We analyse the influences of parameters: temperature, dislocation density, impurity content. The number of point defects created by one initial fission is determined for pure and annealed metal. The importance of the self-anneal which occurs immediately in each displacement spike, and the anneal due to a new fission on the damage resulting from a previous fission, are estimated. The focussing distance in [100] direction is found to be about 1000 Angstrom, at 4 deg. K. (author) [French] Ce travail est une etude par microscopie electronique des dislocations induites dans l'uranium {alpha}, soit par deformation plastique, soit par irradiation. Une methode de preparation des lames minces a basse temperature (-110 deg. C) a ete mise au point. Les vecteurs de Burgers des diverses dislocations de macles de ce metal ont ete definis. Les interactions glissements- maclages sont etudiees experimentalement et theoriquement. Des echantillons irradies a divers taux de combustion ont ete examines. Pour expliquer nos resultats micrographiques, et aussi l'ensemble des informations recueillies dans la litterature concernant l'endommagement par irradiation de l'uranium-{alpha}, nous proposons un modele coherent de l'effet des fragments de fission dans ce metal. L'influence des parametres: temperature, densite de dislocations, impuretes est analysee. Le nombre de defauts ponctuels crees

Proton radius, Darwin-Foldy term and radiative corrections

International Nuclear Information System (INIS)

Jentschura, U.D.

2011-01-01

We discuss the role of the so-called Darwin-Foldy term in the evaluation of the proton and deuteron charge radii from atomic hydrogen spectroscopy and nuclear scattering data. The question of whether this term should be included or excluded from the nuclear radius has been controversially discussed in the literature. We attempt to clarify which literature values correspond to which conventions. A detailed discussion of the conventions appears useful because a recent experiment [R. Pohl et al., Nature 466, 213 (2010)] has indicated that there is a discrepancy between the proton charge radii inferred from ordinary ('electronic') atomic hydrogen and muonic hydrogen. We also investigate the role of quantum electrodynamic radiative corrections in the determination of nuclear radii from scattering data, and propose a definition of the nuclear self energy which is compatible with the subtraction of the radiative corrections in scattering experiments. (author)

Radiative corrections to Expt. 416. Backward πN charge exchange. Internal report No. 131

International Nuclear Information System (INIS)

Chen, G.T.Y.

The importance of radiative corrections in elastic hadronic reactions has been reported recently. This report describes the computational techniques and results of applying the radiative corrections to a backward charge-exchange scattering experiment. The particular reaction considered is π - p → π 0 + n + γ Evaluation of the Schwinger term, evaluation of the numerical integration term, evaluation of the region in which the photon is detected and a check of the unitarity condition are considered. Appendixes contain listings of computer codes written to calculate radiative corrections. (19 figures, 2 tables) (U.S.)

Complete analytic results for radiative-recoil corrections to ground-state muonium hyperfine splitting

International Nuclear Information System (INIS)

Karshenboim, S.G.; Shelyuto, V.A.; Eides, M.E.

1988-01-01

Analytic expressions are obtained for radiative corrections to the hyperfine splitting related to the muon line. The corresponding contribution amounts to (Z 2 a) (Za) (m/M) (9/2 ζ(3) - 3π 2 ln 2 + 39/8) in units of the Fermi hyperfine splitting energy. A complete analytic result for all radiative-recoil corrections is also presented

Radiative corrections in K→3π decays

International Nuclear Information System (INIS)

Bissegger, M.; Fuhrer, A.; Gasser, J.; Kubis, B.; Rusetsky, A.

2009-01-01

We investigate radiative corrections to K→3π decays. In particular, we extend the non-relativistic framework developed recently to include real and virtual photons and show that, in a well-defined power counting scheme, the results reproduce corrections obtained in the relativistic calculation. Real photons are included exactly, beyond the soft-photon approximation, and we compare the result with the latter. The singularities generated by pionium near threshold are investigated, and a region is identified where standard perturbation theory in the fine structure constant α may be applied. We expect that the formulae provided allow one to extract S-wave ππ scattering lengths from the cusp effect in these decays with high precision

Radiative corrections to the background of μ → e γ decay

International Nuclear Information System (INIS)

Arbuzov, A.B.; Kuraev, Eh.A.; Magar, E.; Shajkhatdenov, B.G.; Krehl, O.

1998-01-01

Radiative muon decay in the kinematics similar to the neutrinoless decay μ → e γ is considered. Radiative corrections due to one-loop virtual photons and emission of additional soft or hard photons are taken into account. Analytical expressions and numerical estimations are presented

One-loop renormalization and the properties of radiative corrections in the Fried-Yennie gauge

International Nuclear Information System (INIS)

Karshenbojm, S.G.; Shelyuto, V.A.; Ehjdes, M.I.

1988-01-01

One-loop radiative corrections in the Fried-Yennie gauge are investigated. It is shown that the usual on-mass-shell subtraction may be performed in this gauge without use of the infrared photon mass. The behaviour of the diagrams with corrections near the mass-shell is explored, this behaviour turns out to be in the Freid-Yennie gauge milder than in any other gauge and milder than the behaviour of the corresponding graphs without radiative corrections

Higher curvature self-interaction corrections to Hawking radiation

Science.gov (United States)

Fairoos, C.; Sarkar, Sudipta; Yogendran, K. P.

2017-07-01

The purely thermal nature of Hawking radiation from evaporating black holes leads to the information loss paradox. A possible route to its resolution could be if (enough) correlations are shown to be present in the radiation emitted from evaporating black holes. A reanalysis of Hawking's derivation including the effects of self-interactions in general relativity shows that the emitted radiation does deviate from pure thermality; however no correlations exist between successively emitted Hawking quanta. We extend the calculations to Einstein-Gauss-Bonnet gravity and investigate if higher curvature corrections to the action lead to some new correlations in the Hawking spectra. The effective trajectory of a massless shell is determined by solving the constraint equations and the semiclassical tunneling probability is calculated. As in the case of general relativity, the radiation is no longer thermal and there is no correlation between successive emissions. The absence of any extra correlations in the emitted radiations even in Gauss-Bonnet gravity suggests that the resolution of the paradox is beyond the scope of semiclassical gravity.

A practical introduction to electroweak radiative corrections

International Nuclear Information System (INIS)

Drees, M.

1991-05-01

This is a brief introduction into electroweak radiative corrections within the Standard Model, with the emphasis on performing actual calculations. To this end, a complete set of expressions is given that allows the computation of the ρ parameter, the W mass, and Z→fanti f decays for massless fermions, where the anti Manti S scheme has been used. I conclude with an assessment of what we have learned so far from electroweak precision experiments, and a brief outlook. (orig.)

Radiative corrections to two photon physics

International Nuclear Information System (INIS)

Neervan, W.L. van; Vermaseren, J.A.M.

1983-06-01

The authors develop a method to calculate radiative corrections to two photon reactions of the type e + e - →e + e - X where X is an arbitrary final state. To illustrate this they take the example where X stands for a point-like pseudoscalar. It will be shown that the method is an improvement on the standard way in adding real and virtual photon contributions to the (differential) cross-sections. This makes it possible to compute differential and total cross-sections to a very high precision and with a minimum of computer time which is not possible by using more conventional methods. (Auth.)

The construction of standardised equipment expressly adapted to the different methods of radiation control; Realisation de materiel standardise specialement adapte aux divers modes de controle des radiations

Energy Technology Data Exchange (ETDEWEB)

Savouyaud, J; Menoux, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

The authors show what general characteristics must have equipment designed for radiation control. This equipment must make possible the measurement of doses corresponding to 1/10 of the maximum permissible limit. It should be designed for a specific purpose, and finally it should be independent as far as possible. The authors review the different types of control which it is necessary to effect. (author) [French] Les auteurs indiquent quelles doivent etre les caracteristiques generales du materiel de controle des radiations. Ce materiel doit permettre l'appreciation de mesures correspondant au 1/10{sup e} des limites maximales admissibles. Il devrait etre concu pour une fonction determinee, enfin, il doit etre dans la mesure du possible, autonome. Les auteurs passent en revue les differents types de controle qu'il est necessaire de couvrir. (auteur)

Radiative corrections in bumblebee electrodynamics

Directory of Open Access Journals (Sweden)

R.V. Maluf

2015-10-01

Full Text Available We investigate some quantum features of the bumblebee electrodynamics in flat spacetimes. The bumblebee field is a vector field that leads to a spontaneous Lorentz symmetry breaking. For a smooth quadratic potential, the massless excitation (Nambu–Goldstone boson can be identified as the photon, transversal to the vacuum expectation value of the bumblebee field. Besides, there is a massive excitation associated with the longitudinal mode and whose presence leads to instability in the spectrum of the theory. By using the principal-value prescription, we show that no one-loop radiative corrections to the mass term is generated. Moreover, the bumblebee self-energy is not transverse, showing that the propagation of the longitudinal mode cannot be excluded from the effective theory.

Radiative corrections for semileptonic decays of hyperons: the 'model independent' part

International Nuclear Information System (INIS)

Toth, K.; Szegoe, K.; Margaritis, T.

1984-04-01

The 'model independent' part of the order α radiative correction due to virtual photon exchanges and inner bremsstrahlung is studied for semileptonic decays of hyperons. Numerical results of high accuracy are given for the relative correction to the branching ratio, the electron energy spectrum and the (Esub(e),Esub(f)) Dalitz distribution in the case of four different decays. (author)

Radiative corrections in K{yields}3{pi} decays

Energy Technology Data Exchange (ETDEWEB)

Bissegger, M. [Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland); Fuhrer, A. [Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland); Physics Department, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0319 (United States); Gasser, J. [Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland); Kubis, B. [Helmholtz-Institut fuer Strahlen-und Kernphysik, Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Rusetsky, A. [Helmholtz-Institut fuer Strahlen-und Kernphysik, Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany)

2009-01-01

We investigate radiative corrections to K{yields}3{pi} decays. In particular, we extend the non-relativistic framework developed recently to include real and virtual photons and show that, in a well-defined power counting scheme, the results reproduce corrections obtained in the relativistic calculation. Real photons are included exactly, beyond the soft-photon approximation, and we compare the result with the latter. The singularities generated by pionium near threshold are investigated, and a region is identified where standard perturbation theory in the fine structure constant {alpha} may be applied. We expect that the formulae provided allow one to extract S-wave {pi}{pi} scattering lengths from the cusp effect in these decays with high precision.

Order-α radiative corrections for semileptonic decays of polarized baryons

International Nuclear Information System (INIS)

Glueck, F.; Toth, K.

1992-01-01

Model independent radiative corrections are calculated for the Σ - → neν-bar, Λ → neν-bar and n → peν-bar decays with polarized initial baryons. The method of polarization asymmetry calculations is outlined, and the most important formulae are presented. Numerical results for the corrections to two- and one-dimensional asymmetry distributions and totally integrated asymmetries are tabulated for the electron, neutrino, hadron, α and β asymmetries. (author) 73 refs.; 5 tabs

Bias correction of surface downwelling longwave and shortwave radiation for the EWEMBI dataset

Science.gov (United States)

Lange, Stefan

2018-05-01

Many meteorological forcing datasets include bias-corrected surface downwelling longwave and shortwave radiation (rlds and rsds). Methods used for such bias corrections range from multi-year monthly mean value scaling to quantile mapping at the daily timescale. An additional downscaling is necessary if the data to be corrected have a higher spatial resolution than the observational data used to determine the biases. This was the case when EartH2Observe (E2OBS; Calton et al., 2016) rlds and rsds were bias-corrected using more coarsely resolved Surface Radiation Budget (SRB; Stackhouse Jr. et al., 2011) data for the production of the meteorological forcing dataset EWEMBI (Lange, 2016). This article systematically compares various parametric quantile mapping methods designed specifically for this purpose, including those used for the production of EWEMBI rlds and rsds. The methods vary in the timescale at which they operate, in their way of accounting for physical upper radiation limits, and in their approach to bridging the spatial resolution gap between E2OBS and SRB. It is shown how temporal and spatial variability deflation related to bilinear interpolation and other deterministic downscaling approaches can be overcome by downscaling the target statistics of quantile mapping from the SRB to the E2OBS grid such that the sub-SRB-grid-scale spatial variability present in the original E2OBS data is retained. Cross validations at the daily and monthly timescales reveal that it is worthwhile to take empirical estimates of physical upper limits into account when adjusting either radiation component and that, overall, bias correction at the daily timescale is more effective than bias correction at the monthly timescale if sampling errors are taken into account.

Bias correction of surface downwelling longwave and shortwave radiation for the EWEMBI dataset

Directory of Open Access Journals (Sweden)

S. Lange

2018-05-01

Full Text Available Many meteorological forcing datasets include bias-corrected surface downwelling longwave and shortwave radiation (rlds and rsds. Methods used for such bias corrections range from multi-year monthly mean value scaling to quantile mapping at the daily timescale. An additional downscaling is necessary if the data to be corrected have a higher spatial resolution than the observational data used to determine the biases. This was the case when EartH2Observe (E2OBS; Calton et al., 2016 rlds and rsds were bias-corrected using more coarsely resolved Surface Radiation Budget (SRB; Stackhouse Jr. et al., 2011 data for the production of the meteorological forcing dataset EWEMBI (Lange, 2016. This article systematically compares various parametric quantile mapping methods designed specifically for this purpose, including those used for the production of EWEMBI rlds and rsds. The methods vary in the timescale at which they operate, in their way of accounting for physical upper radiation limits, and in their approach to bridging the spatial resolution gap between E2OBS and SRB. It is shown how temporal and spatial variability deflation related to bilinear interpolation and other deterministic downscaling approaches can be overcome by downscaling the target statistics of quantile mapping from the SRB to the E2OBS grid such that the sub-SRB-grid-scale spatial variability present in the original E2OBS data is retained. Cross validations at the daily and monthly timescales reveal that it is worthwhile to take empirical estimates of physical upper limits into account when adjusting either radiation component and that, overall, bias correction at the daily timescale is more effective than bias correction at the monthly timescale if sampling errors are taken into account.

Radiative corrections for the direct detection of neutralino dark matter and its relic density

Energy Technology Data Exchange (ETDEWEB)

Steppeler, Patrick Norbert

2016-07-01

In this thesis we calculate supersymmetric one-loop corrections of the strong interaction to elastic neutralino-nucleon scattering. The calculation is described in detail and performed in full generality within the Minimal Supersymmetric Standard Model (MSSM). In order to benefit from the well-established tensor reduction method, we have to stabilise the latter for vanishing Gram determinants. Afterwards the radiative corrections are matched onto an effective field theory based on the scalar operator anti χχ anti qq and the axial-vector operator anti χγ{sub 5}γ{sub μ}χ anti qγ{sub 5}γ{sup μ}q. This matching procedure is performed at the high scale μ{sub high}∝1000 GeV, whereas the associated nuclear matrix elements are defined at the low scale μ{sub low}∝5 GeV. To link both scales, the running of the effective operators and their corresponding Wilson coefficients is taken into account via renormalisation group equations. The lightest neutralino can be considered as a canonical example for a weakly interacting, massive particle which could constitute dark matter. To verify the existence of such particles, so-called direct detection experiments are conducted currently. These are based on the interaction between dark matter and nucleons. The leading contributions to the spin-independent and spin-dependent neutralino-nucleon cross sections are governed by the effective operators mentioned above, respectively. The calculation of the associated radiative corrections corresponds to a reduction of the theoretical uncertainty and permits to identify neutralino properties more reliably in case of positive findings and to set more robust exclusion bounds in case of negative findings. Furthermore, we calculate radiative corrections to annihilation and coannihilation processes of gauginos into quarks, where we focus again on supersymmetric one-loop corrections of the strong interaction. These processes contribute dominantly to the (co)annihilation cross section

Study of cerenkov radiation. Production of {gamma} rays by electron accelerators; Etude du rayonnement de freinage. Production de rayons {gamma} par des accelerateurs d'electrons

Energy Technology Data Exchange (ETDEWEB)

Bernard, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

This study is a critical comparison of the theories of Bremsstrahlung. Experimental results obtained by the production of {gamma} radiation with electron accelerators are compared to the theoretical results in order to estimate the extent to which the various theories are valid. (author) [French] Cette etude est une synthese des theories du rayonnement de freinage. Des resultats experimentaux, obtenus par la production de rayonnements {gamma} avec des accelerateurs d'electrons, sont compares aux resultats theoriques afin d'evaluer les domaines de validite des diverses theories. (auteur)

Correction of trace element levels in breast cancer during radiation treatment

International Nuclear Information System (INIS)

Shkala, L.V.

1997-01-01

New method for microelement metabolism correction in patients with comedocarcinoma exposed to radiotherapy was developed and applied. Telegammatherapy was performed 5 time a week at a single dose of 2 Gy, cumulative dose of 40-45 Gy. The method consists in using Trilon B (heavy metal complexone) for correction of microelement metabolism and cupping the syndrome of radiation reactions in combination with dimexide possessing radioprotective properties

Radiation corrections to quantum processes in an intense electromagnetic field

International Nuclear Information System (INIS)

Narozhny, N.B.

1979-01-01

A derivation of an asymptotic expression for the mass correction of order α to the electron propagator in an intense electromagnetic field is presented. It is used for the calculation of radiation corrections to the electron and photon elastic scattering amplitudes in the α 3 approximation. All proper diagrams contributing to the amplitudes and containing the above-mentioned correction to the propagator were considered, but not those which include vertex corrections. It is shown that the expansion parameter of the perturbation theory of quantum electrodynamics in intense fields grows not more slowly than αchi/sup 1/3/ at least for the electron amplitude, where chi = [(eF/sub μν/p/sub ν/) 2 ] 12 /m 3 , p is a momentum of the electron, and F is the electromagnetic field tensor

Contrôle des circuits auxiliaires des P.F.W. (arret machine 2004/2006)

CERN Document Server

Ottaviani, J

2005-01-01

Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d’aimant et constituées d’un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et “pick-up” brasés sur les enroulements principaux). Pendant la variation du champ magnétique de l’aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Chaque année, pendant l’arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre “pick-up” et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, ...

Non perturbative method for radiative corrections applied to lepton-proton scattering

International Nuclear Information System (INIS)

Chahine, C.

1979-01-01

We present a new, non perturbative method to effect radiative corrections in lepton (electron or muon)-nucleon scattering, useful for existing or planned experiments. This method relies on a spectral function derived in a previous paper, which takes into account both real soft photons and virtual ones and hence is free from infrared divergence. Hard effects are computed perturbatively and then included in the form of 'hard factors' in the non peturbative soft formulas. Practical computations are effected using the Gauss-Jacobi integration method which reduce the relevant integrals to a rapidly converging sequence. For the simple problem of the radiative quasi-elastic peak, we get an exponentiated form conjectured by Schwinger and found by Yennie, Frautschi and Suura. We compare also our results with the peaking approximation, which we derive independantly, and with the exact one-photon emission formula of Mo and Tsai. Applications of our method to the continuous spectrum include the radiative tail of the Δ 33 resonance in e + p scattering and radiative corrections to the Feynman scale invariant F 2 structure function for the kinematics of two recent high energy muon experiments

Uses of radioactive isotopes and radiation sources in biological studies in U. A. R; Utilisation des radioisotopes et des sources de rayonnement dans les etudes biologiques en RAU

Energy Technology Data Exchange (ETDEWEB)

Hashish, S. E. [Radiobiology Department, U. A. R. Atomic Energy Establishment, Cairo, United Arab Republic (Egypt)

1970-01-15

An attempt is made to give examples rather than a review of the uses of radioactive isotopes and radiation sources in biological studies in U.A.R. Studies along these lines started early in 1955 and are still progressing. The prospects of future developments and improvements are unlimited. The studies are classified according to the radio technique adopted. The techniques so far used in U.A.R. include all the techniques known elsewhere. Some detailed modifications and combinations of more than one technique have been successfully introduced. Both in basic and applied biological studies, one or more of the following techniques have been applied, namely tracer technique, isotopic dilution analysis, autoradiography, radiochromatography and electrophoresis, double or multi-bioassays, radioactivation analysis, neutron absorption analysis, and use of different radiation source for somatic and/or genetic effect studies. Mass spectrometry for stable isotopic studies in the field of biology has been recently used. Studies undertaken in the applied fields of biology e. g, in medicine (diagnosis and therapy) and agriculture (soil, plant and animal) have proved extremely valuable from the practical and developmental points of view. (author) [French] Le mémoire a pour objet d'illustrer plutôt que d'exposer systématiquement les utilisations des radioisotopes et des sources de rayonnement dans des études biologiques en République Arabe Unie. Ces études, entreprises au début de 1955, se poursuivent. Les possibilités de développement et de perfectionnement sont illimitées. Les études sont classées d'après la radiotechnique adoptée. Les techniques régulièrement utilisées jusqu' à présent en République Arabe Unie couvrent toute la gamme des techniques connues ailleurs. On a réussi à apporter des modifications de détail et à combiner plusieurs techniques. Dans les études de biologie tant fondamentale qu' appliquée, une ou plusieurs des techniques suivantes

Contrôle des Circuits Auxiliaires des PFW (arrêt machines 2002/2003)

CERN Document Server

Ottaviani, J

2003-01-01

Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d aimant et constituées d un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et pick-up brasés sur les enroulements). Pendant la variation du champ magnétique de l aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux courants de Foucault dans la chambre à vide. Chaque année, pendant l arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre pick-up et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, boucles ouvertes ou en court-circuit, déf...

Radiative corrections to chargino production in electron-positron collisions with polarized beams

International Nuclear Information System (INIS)

Diaz, Marco A.; King, Stephen F.; Ross, Douglas A.

2001-01-01

We study radiative corrections to chargino production at linear colliders with polarized electron beams. We calculate the one-loop corrected cross sections for polarized electon beams due to three families of quarks and squarks, working in the {ovr MS} scheme, extending our previous calculation of the unpolarized cross section with one-loop corrections due to the third family of quarks and squarks. In some cases we find rather large corrections to the tree-level cross sections. For example, for the case of right-handed polarized electrons and large tanβ the corrections can be of order 30%, allowing sensitivity to the squark mass parameters

La mesure de pluie par radar : du calibrage par des pluviomètres vers l'interprétation physique des images

OpenAIRE

ANDRIEU, H

2002-01-01

Cet article retrace l'évolution des méthodes de traitement des images radar pour la mesure des précipitations. Les études ont tout donné la priorité au calibrage des images radar par des données pluviométriques de façon à bénéficier des avantages supposés de chaque capteur : représentativité ponctuelle du pluviomètre, continuité spatiale de l'image radar. Bien que positifs, les résultats obtenus ont mis en évidence la nécessité d'une détection et d'une correction des principales sources d'err...

Effets des electrons secondaires sur l'ADN

Science.gov (United States)

Boudaiffa, Badia

Les interactions des electrons de basse energie (EBE) representent un element important en sciences des radiations, particulierement, les sequences se produisant immediatement apres l'interaction de la radiation ionisante avec le milieu biologique. Il est bien connu que lorsque ces radiations deposent leur energie dans la cellule, elles produisent un grand nombre d'electrons secondaires (4 x 104/MeV), qui sont crees le long de la trace avec des energies cinetiques initiales bien inferieures a 20 eV. Cependant, il n'y a jamais eu de mesures directes demontrant l'interaction de ces electrons de tres basse energie avec l'ADN, du principalement aux difficultes experimentales imposees par la complexite du milieu biologique. Dans notre laboratoire, les dernieres annees ont ete consacrees a l'etude des phenomenes fondamentaux induits par impact des EBE sur differentes molecules simples (e.g., N2, CO, O2, H2O, NO, C2H 4, C6H6, C2H12) et quelques molecules complexes dans leur phase solide. D'autres travaux effectues recemment sur des bases de l'ADN et des oligonucleotides ont montre que les EBE produisent des bris moleculaires sur les biomolecules. Ces travaux nous ont permis d'elaborer des techniques pour mettre en evidence et comprendre les interactions fondamentales des EBE avec des molecules d'interet biologique, afin d'atteindre notre objectif majeur d'etudier l'effet direct de ces particules sur la molecule d'ADN. Les techniques de sciences des surfaces developpees et utilisees dans les etudes precitees peuvent etre etendues et combinees avec des methodes classiques de biologie pour etudier les dommages de l'ADN induits par l'impact des EBE. Nos experiences ont montre l'efficacite des electrons de 3--20 eV a induire des coupures simple et double brins dans l'ADN. Pour des energies inferieures a 15 eV, ces coupures sont induites par la localisation temporaire d'un electron sur une unite moleculaire de l'ADN, ce qui engendre la formation d'un ion negatif transitoire

QED radiative correction for the single-W production using a parton shower method

International Nuclear Information System (INIS)

Kurihara, Y.; Fujimoto, J.; Ishikawa, T.; Shimizu, Y.; Kato, K.; Tobimatsu, K.; Munehisa, T.

2001-01-01

A parton shower method for the photonic radiative correction is applied to single W-boson production processes. The energy scale for the evolution of the parton shower is determined so that the correct soft-photon emission is reproduced. Photon spectra radiated from the partons are compared with those from the exact matrix elements, and show a good agreement. Possible errors due to an inappropriate energy-scale selection or due to the ambiguity of the energy-scale determination are also discussed, particularly for the measurements on triple gauge couplings. (orig.)

Radiative corrections to e+e- → W+W- in the Weinberg model

NARCIS (Netherlands)

Veltman, M.J.G.; Lemoine, M.

1980-01-01

The one-loop radiation corrections to the process e+e- ->W+W- are calculated in the Weinberg model. The corrections are computed in a c.m. energy range of 180-1000 GeV. The dependence on the Higgs mass is studied in detail; it is found that variations in the Higgs mass from 10-1000 GeV give rise

Radiative corrections to the lattice gluon action for HISQ improved staggered quarks and the effect of such corrections on the static potential

International Nuclear Information System (INIS)

Hart, A.; Horgan, R.R.

2008-12-01

We perform a perturbative calculation of the influence of dynamical HISQ fermions on the perturbative improvement of the gluonic action in the same way as we have previously done for asqtad fermions. We nd the fermionic contributions to the radiative corrections in the Luescher-Weisz gauge action to be somewhat larger for HISQ fermions than for asqtad. Using one-loop perturbation theory as a test, we estimate that omission of the fermion-induced radiative corrections in dynamical asqtad simulations will give a measurable effect. The one-loop result gives a systematic shift of about -0:6% in r 1 on the coarsest asqtad improved staggered ensembles. This is the correct sign and magnitude to explain the scaling violations seen in Φ B on dynamical lattice ensembles. (orig.)

Effective radiation attenuation calibration for breast density: compression thickness influences and correction

Directory of Open Access Journals (Sweden)

Thomas Jerry A

2010-11-01

Full Text Available Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibration approach based on effective radiation attenuation coefficient measurements was used in the analysis. Water and oil were used to construct phantoms to replicate the deformable properties of the breast. Phantoms consisting of measured proportions of water and oil were used to estimate calibration errors without correction, evaluate the thickness correction, and investigate the reproducibility of the various calibration representations under compression thickness variations. Results The average thickness uncertainty due to compression paddle warp was characterized to within 0.5 mm. The relative calibration error was reduced to 7% from 48-68% with the correction. The normalized effective radiation attenuation coefficient (planar representation was reproducible under intra-sample compression thickness variations compared with calibrated volume measures. Conclusion Incorporating this thickness correction into the rigid breast tissue equivalent calibration method should improve the calibration accuracy of mammograms for risk assessments using the reproducible planar calibration measure.

Contrôle des Circuits Auxiliaires des P.F.W. (arrêt machine 2003/2004)

CERN Document Server

Ottaviani, J

2004-01-01

Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d'aimant et constituées d'un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et des circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et "pick-up" brasés sur les enroulements principaux). Pendant la variation du champ magnétique del'aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Chaque année, pendant l'arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures de résistances des boucles de tours, résistances entre "pick-up" et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, boucles ouvertes ...

Consideration of the problems of the separate measurement of {beta}, {gamma} and X radiation; Considerations sur les problemes de la dosimetrie individuelle des radiations {beta}, {gamma}, X

Energy Technology Data Exchange (ETDEWEB)

Joffre, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

After outlining the present state of knowledge concerning the determination of doses absorbed by external irradiation for various types of radiation, the author gives figures for the comparative sensitivity of common detectors. He then defines the criteria which have to be considered for the choice of the sensitive medium and of the nature and the thickness of the detector walls. Considered very generally, the detection assembly intended for measuring the dose absorbed at a given point in the organism must be designed with a view to giving the same overall interactions with the radiation considered as those occurring in the organism. (author) [French] Apres avoir precise l'etat de nos connaissances generales actuelles concernant la determination des doses absorbees par irradiation externe pour les divers rayonnements, l'auteur indique la sensibilite comparee des detecteurs usuels. Il definit ensuite les criteres qui doivent etre pris en consideration pour le choix du milieu sensible, de la nature et de l'epaisseur de la paroi des detecteurs. D'une maniere tres generale, l'ensemble de detection destine a mesurer une dose absorbee en un point donne de l'organisme doit etre concu en vue de presenter les memes interactions globales avec le rayonnement etudie que celles mises en jeu dans l'organisme. (auteur)

QED corrections to Planck's radiation law and photon thermodynamics

International Nuclear Information System (INIS)

Partovi, M.H.

1994-01-01

Leading corrections to Planck's radiation formula and other photon thermodynamic functions arising from the pair-mediated photon-photon interaction are calculated. This interaction is found to be attractive and to cause a small increase in occupation number for all modes and a corresponding correction to the equation of state. The results are valid for the range of temperatures well below T e =5.9 GK, the temperature equivalent to the electron mass, a range for which the photon gas is essentially free of pair-produced electrons and positrons. An interesting effect of these corrections is the behavior of the photon gas as an elastic medium and its ability to propagate density perturbations. It is found that the cosmic photon gas subsequent to electron-positron annihilation would have manifested these elastic properties were it not for the presence of the free electrons and their dominance of the photon thermodynamics

Radiative corrections to the beam spin asymmetry in photon electroproduction e polarized p {yields} ep{gamma}

Energy Technology Data Exchange (ETDEWEB)

Fonvieille, H.; Bensafa, I. [LPC-Clermont-Fd, Universite Blaise Pascal, F-63170 Aubiere Cedex (France)

2006-11-15

We have measured at MAMI the beam single spin asymmetry (SSA) in exclusive photon electroproduction (e polarized p {yields} ep{gamma}) with a longitudinally polarized beam, in the region of the {delta}(1232) resonance. In this document the value of the radiative correction to this asymmetry is obtained for our kinematics. Although the correction is expected to be very small and negligible, its value is needed as a confirmation and for the purpose of systematic error estimate. The parameter of kinematics are given as follows: four-momentum transfer of the virtual photon, Q{sup 2} = 0.35 GeV{sup 2}; total energy in the ({gamma}p) center of mass, W=1.190 GeV; polarization of the virtual photon, {epsilon}=0.48; azimuthal angle (lepton-hadron planes), {phi} = 220 angle; polar angle of Compton scattering in center of mass, {theta}{sub {gamma}}{sub {gamma}} in [0 angle, 40 angle]; incoming electron beam energy, E{sub e} = 0.88 GeV; scattered electron energy, E{sub 0}' = 0.40 GeV; polar angle of scattered electron {theta}{sub e} = 59.9 angle. The radiative correction is calculated by the radcorr code written by M. Vanderhaeghen, in a version adapted to beam spin asymmetries.In practice, the conclusions are twofold: - the asymmetry that was measured in the VCS channel does not need to be corrected for radiative effects, given the large statistical error bar attached to the experimental values (an asymmetry of 1-10 % with a statistical error bar of 3-4 %); - a systematic error {delta}SSA{sub syst} on the asymmetry will be considered, related to uncertainties in the calculation of the radiative correction (at least two of them have been mentioned here: the cross section model and the soft photon limit). To estimate this error a 100 % variation of the radiative correction was assumed. For the radiative correction itself the maximal value found was taken. Therefore one can take: {delta}SSA{sub syst} = {+-}2.7 x 10{sup -3}.

Radiative corrections to the beam spin asymmetry in photon electroproduction e polarized p → epγ

International Nuclear Information System (INIS)

Fonvieille, H.; Bensafa, I.

2006-11-01

We have measured at MAMI the beam single spin asymmetry (SSA) in exclusive photon electroproduction (e polarized p → epγ) with a longitudinally polarized beam, in the region of the Δ(1232) resonance. In this document the value of the radiative correction to this asymmetry is obtained for our kinematics. Although the correction is expected to be very small and negligible, its value is needed as a confirmation and for the purpose of systematic error estimate. The parameter of kinematics are given as follows: four-momentum transfer of the virtual photon, Q 2 = 0.35 GeV 2 ; total energy in the (γp) center of mass, W=1.190 GeV; polarization of the virtual photon, ε=0.48; azimuthal angle (lepton-hadron planes), φ = 220 angle; polar angle of Compton scattering in center of mass, θ γγ in [0 angle, 40 angle]; incoming electron beam energy, E e = 0.88 GeV; scattered electron energy, E 0 ' = 0.40 GeV; polar angle of scattered electron θ e = 59.9 angle. The radiative correction is calculated by the radcorr code written by M. Vanderhaeghen, in a version adapted to beam spin asymmetries.In practice, the conclusions are twofold: - the asymmetry that was measured in the VCS channel does not need to be corrected for radiative effects, given the large statistical error bar attached to the experimental values (an asymmetry of 1-10 % with a statistical error bar of 3-4 %); - a systematic error ΔSSA syst on the asymmetry will be considered, related to uncertainties in the calculation of the radiative correction (at least two of them have been mentioned here: the cross section model and the soft photon limit). To estimate this error a 100 % variation of the radiative correction was assumed. For the radiative correction itself the maximal value found was taken. Therefore one can take: ΔSSA syst = ±2.7 x 10 -3

Radiative corrections in K→πl+l- decays

International Nuclear Information System (INIS)

Kubis, Bastian; Schmidt, Rebekka

2010-01-01

We calculate radiative corrections to the flavor-changing neutral current process K→πl + l - , both for charged and neutral kaon decays. While the soft-photon approximation is shown to work well for the muon channels, we discuss the necessity of further phase space cuts with electrons in the final state. It is also shown how to transfer our results to other decays such as η→γl + l - or ω→π 0 l + l - . (orig.)

Study of {gamma} radiation from uranium rods during deactivation; Etude du rayonnement {gamma} des barres d'uranium en court de desactivation

Energy Technology Data Exchange (ETDEWEB)

Balestic, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

The classical formulae giving the {gamma} activities of the fission products contained in a uranium rod after unloading from the pile are reviewed without being proved. The knowledge of these activities makes it possible, by means of the method proposed here, to determine the intensities of ionisation at a point outside the rod, and thus to establish {gamma} radiation diagrams. The different parameters introduced in the calculation are geometric (dimensions of the bars and coordinates of the point considered), energetic (power at which the bar has been irradiated) and temporal (duration of the irradiation and deactivation). A numerical example follows the demonstration of the general formulae, {gamma} flux measurements carried out in the deactivation well of P2 (Saclay pile) define the accuracy of the method. In conclusion, it is suggested that radiation diagrams be used in (planning the use of) industrial irradiators for radiochemical polymerisation or the preservation of food products. (author) [French] On rappelle sans demonstration les formules classiques donnant les activites {gamma} des produits de fission contenus dans une barre d'uranium apres defournement. La connaissance de ces activites permet par la methode proposee de passer aux intensites d'ionisation en un point exterieur a la barre et d'etablir ainsi des diagrammes de rayonnement {gamma}. Les differents parametres introduits dans le calcul sont d'ordre geometrique (dimensions des barres et coordonnees du point considere), d'ordre energetique (puissance a laquelle la barre a ete irradiee) et fonction du temps (duree d'irradiation et de desactivation). Un exemple numerique fait suite a la demonstration des formules generales. Des mesures de flux {gamma} effectuees au puits de desactivation de P2 (pile de Saclay) fixent le degre d'approximation de la methode. En conclusion, on suggere l'utilisation des diagrammes de rayonnement dans l'etablissement de projets d'irradiateurs industriels pour les

Economic outlook for radiometric selection of ores; Possibilites ouvertes en matiere economique par selection radiometrique des minerais

Energy Technology Data Exchange (ETDEWEB)

Formery, P; Ziegler, V [Commissariat a l' Energie Atomique, Usine du Bouchet, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

The value of an ore can be increased by cutting off it's poor fractions. This selection may be realized at two stages: - part of the ore in situ is unable to cover it's extraction and treatment costs, this defines the 'underground cut-off grade'; - another portion of already extracted ore is unable to cover it's transport and treatment costs; this defines the 'surface cut off grade'. These selections are easily feasible owing to the property of uranium ores of emitting gamma radiations. A diagram makes possible a fast forecast on the effect of this selection upon the weight and metal yields. An attempt is made as well in order to provide the expected effect of the composition of underground cut off and surface cut off. This cut off however, being realized through an appreciation of the radiations, involves an alteration of the weight and metal yields which calls for a correction. A survey of the economic interest of the cut-off is done and an example of valorisation in a given deposit of a section at the limit of operability is proposed. (author) [French] On peut augmenter la valeur d'un minerai en retranchant des fractions pauvres de minerai. Cette selection peut etre realisee a deux stades: - eviter l'abattage d'un minerai incapable de supporter les frais d'extraction et de traitement. On definit ainsi une teneur de 'coupure fond'; - eviter de traiter chimiquement des fractions de minerai deja extraites mais dont la teneur ne justifie pas le transport et le traitement. On definit ainsi une teneur de coupure jour. La propriete des minerais d'uranium d'emettre des rayonnements gamma dont la densite est liee a la teneur permet de realiser tres aisement cette selection. On propose un diagramme permettant de prevoir rapidement l'incidence de cette selection sur les rendements poids et metal. On a tente de prevoir l'effet d'une composition des coupures fond et jour. Toutefois, la coupure etant realisee par une appreciation des rayonnements, il s'introduit une certaine

Analytic calculation of radiative-recoil corrections to muonium hyperfine splitting: Electron-line contribution

International Nuclear Information System (INIS)

Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1991-01-01

The detailed account of analytic calculation of radiative-recoil correction to muonium hyperfine splitting, induced by electron-line radiative insertions, is presented. The consideration is performed in the framework of the effective two-particle formalism. A good deal of attention is paid to the problem of the divergence cancellation and the selection of graphs, relevant to radiative-recoil corrections. The analysis is greatly facilitated by use of the Fried-Yennie gauge for radiative photons. The obtained set of graphs turns out to be gauge-invariant and actual calculations are performed in the Feynman gauge. The main technical tricks, with the help of which we have effectively utilized the existence in the problem of the small parameter-mass ratio and managed to perform all calculations in the analytic form are described. The main intermediate results, as well as the final answer, δE rr = (α(Ζα)/π 2 )(m/M)E F (6ζ(3) + 3π 2 In 2 + π 2 /2 + 17/8), are also presented

Are radiative corrections to the Mikheyev-Smirnov-Wolfenstein formula affected by finite temperature and density?

International Nuclear Information System (INIS)

Horvat, R.

1993-01-01

One-loop photonic corrections to the electron-neutrino (ν e ) charged-current medium induced self-energy are examined using finite temperature field theory. It is shown that irrespective of computing radiative corrections at finite temperature and density, there are no O(α) corrections to the charged-current contribution of the ν e 's dispersion relation

Minimal and non-minimal standard models: Universality of radiative corrections

International Nuclear Information System (INIS)

Passarino, G.

1991-01-01

The possibility of describing electroweak processes by means of models with a non-minimal Higgs sector is analyzed. The renormalization procedure which leads to a set of fitting equations for the bare parameters of the lagrangian is first reviewed for the minimal standard model. A solution of the fitting equations is obtained, which correctly includes large higher-order corrections. Predictions for physical observables, notably the W boson mass and the Z O partial widths, are discussed in detail. Finally the extension to non-minimal models is described under the assumption that new physics will appear only inside the vector boson self-energies and the concept of universality of radiative corrections is introduced, showing that to a large extent they are insensitive to the details of the enlarged Higgs sector. Consequences for the bounds on the top quark mass are also discussed. (orig.)

Radiative corrections to the hadronic cross-section measurement at DA{phi}NE

Energy Technology Data Exchange (ETDEWEB)

Khoze, V.A. [Durham Univ. of Durham, Durham (United Kingdom). Dept. of Physics; Konchatnij, M.I.; Merenkov, NP.; Shekhovzova, O.N. [National Science Centre Kharkov Institute of Physics and Technology, Karkhov (Ukraine); Pancheri, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Trentadue, L. [Parma Univ., Parma (Italy). Dipt. di Fisica

2000-07-01

The hadronic invariant mass distribution for the process of electron--positron annihilation into a pair of charged pions accompanied by a photon radiated from the initial state has been studied for the region of DA{phi}NE energies. The Born cross-section and the electromagnetic radiative corrections to it are calculated for realistic conditions of the KLOE detector. The dependence on the physical parameters which define the event selection is obtained.

Radiative corrections to top and bottom production at collider energies

International Nuclear Information System (INIS)

Dawson, S.

1988-10-01

We discuss the results of a full calculation of the QCD O(α 8 /sup s/) radiative corrections to the differential cross section for the production of a heavy quark pair. Numerical results are presented for bottom and top production in p/bar p/ collisions at /square root/s = 1.8 TeV. 2 refs., 2 figs

Electroweak vacuum stability and finite quadratic radiative corrections

Energy Technology Data Exchange (ETDEWEB)

Masina, Isabella [Ferrara Univ. (Italy). Dipt. di Fisica e Scienze della Terra; INFN, Sezione di Ferrara (Italy); Southern Denmark Univ., Odense (Denmark). CP3-Origins; Southern Denmark Univ., Odense (Denmark). DIAS; Nardini, Germano [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Quiros, Mariano [Institucio Catalana de Recerca i Estudis Avancats (ICREA), Barcelona (Spain); IFAE-IAB, Barcelona (Spain)

2015-07-15

If the Standard Model (SM) is an effective theory, as currently believed, it is valid up to some energy scale Λ to which the Higgs vacuum expectation value is sensitive throughout radiative quadratic terms. The latter ones destabilize the electroweak vacuum and generate the SM hierarchy problem. For a given perturbative Ultraviolet (UV) completion, the SM cutoff can be computed in terms of fundamental parameters. If the UV mass spectrum involves several scales the cutoff is not unique and each SM sector has its own UV cutoff Λ{sub i}. We have performed this calculation assuming the Minimal Supersymmetric Standard Model (MSSM) is the SM UV completion. As a result, from the SM point of view, the quadratic corrections to the Higgs mass are equivalent to finite threshold contributions. For the measured values of the top quark and Higgs masses, and depending on the values of the different cutoffs Λ{sub i}, these contributions can cancel even at renormalization scales as low as multi-TeV, unlike the case of a single cutoff where the cancellation only occurs at Planckian energies, a result originally obtained by Veltman. From the MSSM point of view, the requirement of stability of the electroweak minimum under radiative corrections is incorporated into the matching conditions and provides an extra constraint on the Focus Point solution to the little hierarchy problem in the MSSM. These matching conditions can be employed for precise calculations of the Higgs sector in scenarios with heavy supersymmetric fields.

Correcting surface solar radiation of two data assimilation systems against FLUXNET observations in North America

Science.gov (United States)

Zhao, Lei; Lee, Xuhui; Liu, Shoudong

2013-09-01

Solar radiation at the Earth's surface is an important driver of meteorological and ecological processes. The objective of this study is to evaluate the accuracy of the reanalysis solar radiation produced by NARR (North American Regional Reanalysis) and MERRA (Modern-Era Retrospective Analysis for Research and Applications) against the FLUXNET measurements in North America. We found that both assimilation systems systematically overestimated the surface solar radiation flux on the monthly and annual scale, with an average bias error of +37.2 Wm-2 for NARR and of +20.2 Wm-2 for MERRA. The bias errors were larger under cloudy skies than under clear skies. A postreanalysis algorithm consisting of empirical relationships between model bias, a clearness index, and site elevation was proposed to correct the model errors. Results show that the algorithm can remove the systematic bias errors for both FLUXNET calibration sites (sites used to establish the algorithm) and independent validation sites. After correction, the average annual mean bias errors were reduced to +1.3 Wm-2 for NARR and +2.7 Wm-2 for MERRA. Applying the correction algorithm to the global domain of MERRA brought the global mean surface incoming shortwave radiation down by 17.3 W m-2 to 175.5 W m-2. Under the constraint of the energy balance, other radiation and energy balance terms at the Earth's surface, estimated from independent global data products, also support the need for a downward adjustment of the MERRA surface solar radiation.

prise en charge tardive des sequelles de fractures du plancher

African Journals Online (AJOL)

19 déc. 2007 ... d'abord adaptées, libération du foyer de fracture de la péri orbite et des ailerons musculaires, réduction des frag- ments osseux déplacés et contention par ostéosynthèse au fil d'acier ou par plaques vissées (7, 8,9), comblement des défects osseux par greffes osseuses ou implants, et correction des lésions ...

Improvement in remote sensing of low vegetation cover in arid regions by correcting vegetation indices for soil ''noise''; Etude des propriétés spectrales des sols arides appliquée à l'amélioration des indices de végétation obtenus par télédétection

Energy Technology Data Exchange (ETDEWEB)

Escadafal, R. [Institut Francais de Recherche Scientifique pour le Developpement en Cooperation, Bondy (France); Huete, A.

1991-05-23

The variations of near-infrared red reflectance ratios of ten aridic soil samples were correlated with a ''redness index'' computed from red and green spectral bands. These variations have been shown to limit the performances of vegetation indices (NDVI and SAVI) in discriminating low vegetation covers. The redness index is used to adjust for this ''soil noise''. Dala simulated for vegetation densities of 5 to 15% cover showed that the sensitivity of the corrected vegetation indices was significantly improved. Specifically, the ''noise-corrected'' SAVI was able to assess vegetation amounts with an error four times smaller than the uncorrected NDVI. These promising results should lead to a significant improvement in assessing biomass in arid lands from remotely sensed data. (author) [French] Les variations du rapport de la réflectance dans les bandes rouge et infrarouge sont mises en relation avec un (( indice de coloration )) pouf une série de dix sols arides. Ces variations gZnent fortement la détection des faibles taux de couvert végétal avec les indices de végétation (NDVI et SAVI) calculés à partir de ces deux bandes. Il est proposé d’utiliser l’indice de coloration comme facteur de correction de ce (( bruit )) dû au sol. Une simulation de la reflectance des sols avec une couverture végétale variant de O à 15 % en évidence un doublement de la sensibilité des indices de végétation ainsi corrigés. En particulier, le SAVI corrigé permet d’estimer le taux de végétation avec une erreur quatre fois inférieure à celle du NDVI non corrigé. Ces premiers résultats devraient conduire à une amélioration sensible de la mesure de la biomasse végétale des régions arides par télédétection. (author)

Evaluation of heterogeneity corrections in stereotactic body radiation therapy for the lung

International Nuclear Information System (INIS)

Matsuo, Yukinori; Narita, Yuichiro; Nakata, Manabu

2008-01-01

The purpose was to evaluate impact of heterogeneity corrections on dose distributions for stereotactic body radiation therapy (SBRT) for the lung. This study was conducted with the treatment plans of 28 cases in which we performed SBRT for solitary lung tumors with 48 Gy in 12-Gy fractions at the isocenter. The treatment plans were recalculated under three conditions of heterogeneity correction as follows: pencil beam convolution with Batho power law correction (PBC-BPL), pencil beam convolution with no correction (PBC-NC), and anisotropic analytical algorithm with heterogeneity correction (AAA). Dose-volumetric data were compared among the three conditions. Heterogeneity corrections had a significant impact on all dose-volumetric parameters. Means of isocenter dose were 48.0 Gy, 44.6 Gy, and 48.4 Gy in PBC-BPL, PBC-NC, and AAA, respectively. PTV D95 were 45.2 Gy, 41.1 Gy, and 42.1 Gy, and V20 of the lung were 4.1%, 3.7%, and 3.9%, respectively. Significant differences in dose distribution were observed among heterogeneity corrections. Attention needs to be paid to the differences. (author)

Elaboration de nouvelles approches micromecaniques pour l'optimisation des performances mecaniques des materiaux heterogenes

Science.gov (United States)

Aboutajeddine, Ahmed

Les modeles micromecaniques de transition d'echelles qui permettent de determiner les proprietes effectives des materiaux heterogenes a partir de la microstructure sont consideres dans ce travail. L'objectif est la prise en compte de la presence d'une interphase entre la matrice et le renforcement dans les modeles micromecaniques classiques, de meme que la reconsideration des approximations de base de ces modeles, afin de traiter les materiaux multiphasiques. Un nouveau modele micromecanique est alors propose pour tenir compte de la presence d'une interphase elastique mince lors de la determination des proprietes effectives. Ce modele a ete construit grace a l'apport de l'equation integrale, des operateurs interfaciaux de Hill et de la methode de Mori-Tanaka. Les expressions obtenues pour les modules globaux et les champs dans l'enrobage sont de nature analytique. L'approximation de base de ce modele est amelioree par la suite dans un nouveau modele qui s'interesse aux inclusions enrobees avec un enrobage mince ou epais. La resolution utilisee s'appuie sur une double homogeneisation realisee au niveau de l'inclusion enrobee et du materiau. Cette nouvelle demarche, permettra d'apprehender completement les implications des approximations de la modelisation. Les resultats obtenus sont exploites par la suite dans la solution de l'assemblage de Hashin. Ainsi, plusieurs modeles micromecaniques classiques d'origines differentes se voient unifier et rattacher, dans ce travail, a la representation geometrique de Hashin. En plus de pouvoir apprecier completement la pertinence de l'approximation de chaque modele dans cette vision unique, l'extension correcte de ces modeles aux materiaux multiphasiques est rendue possible. Plusieurs modeles analytiques et explicites sont alors proposee suivant des solutions de differents ordres de l'assemblage de Hashin. L'un des modeles explicite apparait comme une correction directe du modele de Mori-Tanaka, dans les cas ou celui ci echoue a

Stray light correction on array spectroradiometers for optical radiation risk assessment in the workplace

International Nuclear Information System (INIS)

Barlier-Salsi, A

2014-01-01

The European directive 2006/25/EC requires the employer to assess and, if necessary, measure the levels of exposure to optical radiation in the workplace. Array spectroradiometers can measure optical radiation from various types of sources; however poor stray light rejection affects their accuracy. A stray light correction matrix, using a tunable laser, was developed at the National Institute of Standards and Technology (NIST). As tunable lasers are very expensive, the purpose of this study was to implement this method using only nine low power lasers; other elements of the correction matrix being completed by interpolation and extrapolation. The correction efficiency was evaluated by comparing CCD spectroradiometers with and without correction and a scanning double monochromator device as reference. Similar to findings recorded by NIST, these experiments show that it is possible to reduce the spectral stray light by one or two orders of magnitude. In terms of workplace risk assessment, this spectral stray light correction method helps determine exposure levels, with an acceptable degree of uncertainty, for the majority of workplace situations. The level of uncertainty depends upon the model of spectroradiometers used; the best results are obtained with CCD detectors having an enhanced spectral sensitivity in the UV range. Thus corrected spectroradiometers require a validation against a scanning double monochromator spectroradiometer before using them for risk assessment in the workplace. (paper)

Stray light correction on array spectroradiometers for optical radiation risk assessment in the workplace.

Science.gov (United States)

Barlier-Salsi, A

2014-12-01

The European directive 2006/25/EC requires the employer to assess and, if necessary, measure the levels of exposure to optical radiation in the workplace. Array spectroradiometers can measure optical radiation from various types of sources; however poor stray light rejection affects their accuracy. A stray light correction matrix, using a tunable laser, was developed at the National Institute of Standards and Technology (NIST). As tunable lasers are very expensive, the purpose of this study was to implement this method using only nine low power lasers; other elements of the correction matrix being completed by interpolation and extrapolation. The correction efficiency was evaluated by comparing CCD spectroradiometers with and without correction and a scanning double monochromator device as reference. Similar to findings recorded by NIST, these experiments show that it is possible to reduce the spectral stray light by one or two orders of magnitude. In terms of workplace risk assessment, this spectral stray light correction method helps determine exposure levels, with an acceptable degree of uncertainty, for the majority of workplace situations. The level of uncertainty depends upon the model of spectroradiometers used; the best results are obtained with CCD detectors having an enhanced spectral sensitivity in the UV range. Thus corrected spectroradiometers require a validation against a scanning double monochromator spectroradiometer before using them for risk assessment in the workplace.

Radiative corrections in 5D and 6D expanding in winding modes

International Nuclear Information System (INIS)

Rold, Leandro da

2004-01-01

We compute radiative corrections in five- and six-dimensional field theories, using winding modes in mixed momentum-coordinate space. This method provides a simple way of finding UV divergencies, finite corrections and localized terms when the space is compactified on orbifolds. As an application we compute the finite piece of scalar masses, the logarithmic contributions to the couplings and the effect of localized parallel and perpendicular kinetic terms. We apply it to get a two loop effective potential that can stabilize large extra dimensions

Economic outlook for radiometric selection of ores; Possibilites ouvertes en matiere economique par selection radiometrique des minerais

Energy Technology Data Exchange (ETDEWEB)

Formery, P.; Ziegler, V. [Commissariat a l' Energie Atomique, Usine du Bouchet, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

The value of an ore can be increased by cutting off it's poor fractions. This selection may be realized at two stages: - part of the ore in situ is unable to cover it's extraction and treatment costs, this defines the 'underground cut-off grade'; - another portion of already extracted ore is unable to cover it's transport and treatment costs; this defines the 'surface cut off grade'. These selections are easily feasible owing to the property of uranium ores of emitting gamma radiations. A diagram makes possible a fast forecast on the effect of this selection upon the weight and metal yields. An attempt is made as well in order to provide the expected effect of the composition of underground cut off and surface cut off. This cut off however, being realized through an appreciation of the radiations, involves an alteration of the weight and metal yields which calls for a correction. A survey of the economic interest of the cut-off is done and an example of valorisation in a given deposit of a section at the limit of operability is proposed. (author) [French] On peut augmenter la valeur d'un minerai en retranchant des fractions pauvres de minerai. Cette selection peut etre realisee a deux stades: - eviter l'abattage d'un minerai incapable de supporter les frais d'extraction et de traitement. On definit ainsi une teneur de 'coupure fond'; - eviter de traiter chimiquement des fractions de minerai deja extraites mais dont la teneur ne justifie pas le transport et le traitement. On definit ainsi une teneur de coupure jour. La propriete des minerais d'uranium d'emettre des rayonnements gamma dont la densite est liee a la teneur permet de realiser tres aisement cette selection. On propose un diagramme permettant de prevoir rapidement l'incidence de cette selection sur les rendements poids et metal. On a tente de prevoir l'effet d'une composition des coupures fond et jour. Toutefois, la

Higgs mass dependence of electroweak radiative corrections and the triviality bound

NARCIS (Netherlands)

Cortese, S.; Pallante, E.; Petronzio, R.

1993-01-01

We discuss how the existence of a triviality bound for the Higgs sector of the standard model does influence the dependence of radiative corrections upon the Higgs mass. The lowering of the Landau pole with increasing Higgs mass implies that the sensitivity to Higgs mass values beyond ≈ 500 GeV is

Ventilation of radioactive enclosures; Ventilation des enceintes radioactives

Energy Technology Data Exchange (ETDEWEB)

Caminade, F; Laurent, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

Mechanical, physical and chemical manipulations on radioactive products must be carried out in properly ventilated enclosed places. The air extracted can only be discharged into the atmosphere after a correct filtration. The power of the ventilation systems is a function of the dimensions and purpose of the enclosure? The choice of types of filter is determined by the physical state and chemical nature of the radioactive materials to be manipulated. This study deals with the individual equipment of small installations: glove boxes, manipulation boxes with outside control and, if necessary, production chambers (maximum useful volume: 5 m{sup 3}). The performances of three types of 'ventilators', and the modifications provided by the addition of filters, are measured and compared. (author) [French] Les manipulations oceaniques, physiques et chimiques sur des produits radioactifs doivent s'effectuer dans des enceintes convenablement ventilees. L'air extrait ne peut etre rejete dans l'atmosphere qu'apres une filtration correcte. La puissance des installations de ventilation est fonction des dimensions de l'enceinte et de son utilisation. Le choix des types de filtres est determine par l'etat physique et la nature ehimique des corps radioactifs manipules. Notre etude porte sur l'equipement individuel d'installations de petites dimensions: boites a gants, boites a pinces et, a la rigueur, enceintes de production (volume maximum utilisable 5 m{sup 3}). Nous mesurons et comparons les performances de trois types de 'ventilateurs' et les modifications apportees par l'adjonction de filtres. (auteur)

Does Correct Answer Distribution Influence Student Choices When Writing Multiple Choice Examinations?

Directory of Open Access Journals (Sweden)

Jacqueline A. Carnegie

2017-03-01

��évaluation sommative se déroule souvent par le biais d’examens comportant des questions à choix multiples afin de pouvoir donner rapidement les résultats aux étudiants. Plusieurs versions de ces examens sont souvent préparées et les questions sont brouillées par ordinateur pour dissuader la tricherie. Lors de la préparation de plusieurs versions d’un examen à choix multiples, l’un des paramètres importants à prendre en considération est que chaque version doit être semblable aux autres pour évaluer équitablement les connaissances des étudiants. Ce projet a pour but d’examiner l’influence possible de l’organisation des réponses correctes sur le choix des réponses des étudiants lors de la préparation de plusieurs versions d’un examen à choix multiples. La question spécifique qui a été posée était de savoir si l’existence d’une série de quatre ou cinq questions à choix multiples consécutives pour lesquelles la même lettre représentait la bonne réponse pouvait avoir une influence préjudiciable sur l’aptitude des étudiants à continuer à choisir la bonne réponse alors qu’ils progressent d’une question à l’autre dans la même série. Les résultats des étudiants qui passent de tels examens ont été comparés aux résultats obtenus quand les étudiants passent des examens dont les questions sont les mêmes mais qui ne comportent pas de telles séries. Ces résultats ont été enrichis par les réponses à une enquête auprès des étudiants pour laquelle les étudiants ont été auto-évalués concernant la question de savoir s’ils avaient remarqué la répartition des réponses correctes parmi les choix multiples quand ils passaient des examens sommatifs, à la fois au départ, quand ils choisissaient leurs réponses, et ensuite quand ils transféraient les lettres correspondant à leurs réponses sur la feuille Scanton pour la correction. Malgré le fait que plus de la moitié des répondants aient indiqué qu’ils ne font

Electroweak radiative corrections to e+e-→WW→4 fermions in double-pole approximation -- the RACOONWW approach

International Nuclear Information System (INIS)

Denner, A.; Dittmaier, S.; Roth, M.; Wackeroth, D.

2000-01-01

We calculate the complete O(α) electroweak radiative corrections to e + e - →WW→4f in the electroweak Standard Model in the double-pole approximation. We give analytical results for the non-factorizable virtual corrections and express the factorizable virtual corrections in terms of the known corrections to on-shell W-pair production and W decay. The calculation of the bremsstrahlung corrections, i.e., the processes e + e - →4fγ in lowest order, is based on the full matrix elements. The matching of soft and collinear singularities between virtual and real corrections is done alternatively in two different ways, namely by using a subtraction method and by applying phase-space slicing. The O(α) corrections as well as higher-order initial-state photon radiation are implemented in the Monte Carlo generator RACOONWW. Numerical results of this program are presented for the W-pair-production cross section, angular and W-invariant-mass distributions at LEP2. We also discuss the intrinsic theoretical uncertainty of our approach

Star formation through thermal instability of radiative plasma with finite electron inertia and finite Larmor radius corrections

Energy Technology Data Exchange (ETDEWEB)

Kaothekar, Sachin, E-mail: sackaothekar@gmail.com [Department of Physics, Mahakal Institute of Technology, Ujjain-456664, Madhya Pradesh (India)

2016-08-15

I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR) corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM). A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.

Star formation through thermal instability of radiative plasma with finite electron inertia and finite Larmor radius corrections

Directory of Open Access Journals (Sweden)

Sachin Kaothekar

2016-08-01

Full Text Available I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM. A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.

Radiative corrections to the Higgs couplings in the triplet model

International Nuclear Information System (INIS)

KIKUCHI, M.

2014-01-01

The feature of extended Higgs models can appear in the pattern of deviations from the Standard Model (SM) predictions in coupling constants of the SM-like Higgs boson (h). We can thus discriminate extended Higgs models by precisely measuring the pattern of deviations in the coupling constants of h, even when extra bosons are not found directly. In order to compare the theoretical predictions to the future precision data at the ILC, we must evaluate the theoretical predictions with radiative corrections in various extended Higgs models. In this paper, we give our comprehensive study for radiative corrections to various Higgs boson couplings of h in the minimal Higgs triplet model (HTM). First, we define renormalization conditions in the model, and we calculate the Higgs coupling; gγγ, hWW, hZZ and hhh at the one loop level. We then evaluate deviations in coupling constants of the SM-like Higgs boson from the predictions in the SM. We find that one-loop contributions to these couplings are substantial as compared to their expected measurement accuracies at the ILC. Therefore the HTM has a possibility to be distinguished from the other models by comparing the pattern of deviations in the Higgs boson couplings.

One-loop radiative correction to the triple Higgs coupling in the Higgs singlet model

Directory of Open Access Journals (Sweden)

Shi-Ping He

2017-01-01

Full Text Available Though the 125 GeV Higgs boson is consistent with the standard model (SM prediction until now, the triple Higgs coupling can deviate from the SM value in the physics beyond the SM (BSM. In this paper, the radiative correction to the triple Higgs coupling is calculated in the minimal extension of the SM by adding a real gauge singlet scalar. In this model there are two scalars h and H and both of them are mixing states of the doublet and singlet. Provided that the mixing angle is set to be zero, namely the SM limit, h is the pure left-over of the doublet and its behavior is the same as that of the SM at the tree level. However the loop corrections can alter h-related couplings. In this SM limit case, the effect of the singlet H may show up in the h-related couplings, especially the triple h coupling. Our numerical results show that the deviation is sizable. For λΦS=1 (see text for the parameter definition, the deviation δhhh(1 can be 40%. For λΦS=1.5, the δhhh(1 can reach 140%. The sizable radiative correction is mainly caused by three reasons: the magnitude of the coupling λΦS, light mass of the additional scalar and the threshold enhancement. The radiative corrections for the hVV, hff couplings are from the counter-terms, which are the universal correction in this model and always at O(1%. The hZZ coupling, which can be precisely measured, may be a complementarity to the triple h coupling to search for the BSM. In the optimal case, the triple h coupling is very sensitive to the BSM physics, and this model can be tested at future high luminosity hadron colliders and electron–positron colliders.

Six-dimensional correction of intra-fractional prostate motion with CyberKnife stereotactic body radiation therapy

Directory of Open Access Journals (Sweden)

Sean eCollins

2011-12-01

Full Text Available AbstractLarge fraction radiation therapy offers a shorter course of treatment and radiobiological advantages for prostate cancer treatment. The CyberKnife is an attractive technology for delivering large fraction doses based on the ability to deliver highly conformal radiation therapy to moving targets. In addition to intra-fractional translational motion (left-right, superior-inferior and anterior-posterior, prostate rotation (pitch, roll and yaw can increase geographical miss risk. We describe our experience with six-dimensional (6D intrafraction prostate motion correction using CyberKnife stereotactic body radiation therapy (SBRT. Eighty-eight patients were treated by SBRT alone or with supplemental external radiation therapy. Trans-perineal placement of four gold fiducials within the prostate accommodated X-ray guided prostate localization and beam adjustment. Fiducial separation and non-overlapping positioning permitted the orthogonal imaging required for 6D tracking. Fiducial placement accuracy was assessed using the CyberKnife fiducial extraction algorithm. Acute toxicities were assessed using Common Toxicity Criteria (CTC v3. There were no Grade 3, or higher, complications and acute morbidity was minimal. Ninety-eight percent of patients completed treatment employing 6D prostate motion tracking with intrafractional beam correction. Suboptimal fiducial placement limited treatment to 3D tracking in 2 patients. Our experience may guide others in performing 6D correction of prostate motion with CyberKnife SBRT.

Patients radiation protection in medical imaging. Conference proceedings; Radioprotection des patients en imagerie medicale. Recueil des presentations

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-12-15

This document brings together the available presentations given at the conference organised by the French society of radiation protection about patients radiation protection in medical imaging. Twelve presentations (slides) are compiled in this document and deal with: 1 - Medical exposure of the French population: methodology and results (Bernard Aubert, IRSN); 2 - What indicators for the medical exposure? (Cecile Etard, IRSN); 3 - Guidebook of correct usage of medical imaging examination (Philippe Grenier, Pitie-Salpetriere hospital); 4 - Radiation protection optimization in pediatric imaging (Hubert Ducou-Le-Pointe, Aurelien Bouette (Armand-Trousseau children hospital); 5 - Children's exposure to image scanners: epidemiological survey (Marie-Odile Bernier, IRSN); 6 - Management of patient's irradiation: from image quality to good practice (Thierry Solaire, General Electric); 7 - Dose optimization in radiology (Cecile Salvat (Lariboisiere hospital); 8 - Cancer detection in the breast cancer planned screening program - 2004-2009 era (Agnes Rogel, InVS); 9 - Mammographic exposures - radiobiological effects - radio-induced DNA damages (Catherine Colin, Lyon Sud hospital); 10 - Breast cancer screening program - importance of non-irradiating techniques (Anne Tardivon, Institut Curie); 11 - Radiation protection justification for the medical imaging of patients over the age of 50 (Michel Bourguignon, ASN); 12 - Search for a molecular imprint for the discrimination between radio-induced and sporadic tumors (Sylvie Chevillard, CEA)

On the radiative corrections to the neutrino deep inelastic scattering

International Nuclear Information System (INIS)

Bardin, D.Yu.; Dokuchaeva, V.A.

1986-01-01

A unique set of formulae is presented for the radiative corrections to the double differential cross section of deep inelastic neutrino scattering in channels of charged and neutral currents within a simple quark parton model in a renormalization scheme on mass-shell. It is shown that these cross sections when being integrated up to the one-dimensional distribution or up to the total cross section reproduce many results existing in the literature

Study of radiative corrections with application to the electron-neutrino scattering

International Nuclear Information System (INIS)

Oliveira, L.C.S. de.

1977-01-01

The radiative correction method is studied which appears in Quantum Field Theory, for some weak interaction processes. e.g., Beta decay and muon decay. Such a method is then applied to calculate transition probability for the electron-neutrino scattering using the U-A theory as a base. The calculations of infrared and ultraviolet divergences are also discussed. (L.C.) [pt

Vacuum decay in theories with symmetry breaking by radiative corrections

International Nuclear Information System (INIS)

Weinberg, E.J.

1993-01-01

The standard bounce formalism for calculating the decay rate of a metastable vacuum cannot be applied to theories in which the symmetry breaking is due to radiative corrections, because in such theories the tree-level action has no bounce solutions. In this paper I derive a modified formalism to deal with such cases. As in the usual case, the bubble nucleation rate may be written in the form Ae -B . To leading approximation, B is the bounce action obtained by replacing the tree-level potential by the leading one-loop approximation to the effective potential, in agreement with the generally adopted ad hoc remedy. The next correction to B (which is proportional to an inverse power of a small coupling) is given in terms of the next-to-leading term in the effective potential and the leading correction to the two-derivative term in the effective action. The corrections beyond these (which may be included in the prefactor) do not have simple expressions in terms of the effective potential and the other functions in the effective action. In particular, the scalar-loop terms which give an imaginary part to the effective potential do not explicitly appear; the corresponding effects are included in a functional determinant which gives a manifestly real result for the nucleation rate

Radiative corrections of O(α) to B{sup -} → V{sup 0}l{sup -} anti ν{sub l} decays

Energy Technology Data Exchange (ETDEWEB)

Tostado, S.L. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Departamento de Fisica, Mexico, D.F. (Mexico); Castro, G.L. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Departamento de Fisica, Mexico, D.F. (Mexico); CSIC- Universitat de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain)

2016-09-15

The O(α) electromagnetic radiative corrections to the B{sup -} → V{sup 0}l{sup -} anti ν{sub l} (V is a vector meson and l a charged lepton) decay rates are evaluated using the cutoff method to regularize virtual corrections and incorporating intermediate resonance states in the real-photon amplitude to extend the region of validity of the soft-photon approximation. The electromagnetic and weak form factors of hadrons are assumed to vary smoothly over the energies of virtual and real photons under consideration. The cutoff dependence of radiative corrections upon the scale Λ that separates the long- and short-distance regimes is found to be mild and is considered as an uncertainty of the calculation. Owing to partial cancellations of electromagnetic corrections evaluated over the three- and four-body regions of phase space, the photon-inclusive corrected rates are found to be dominated by the short-distance contribution. These corrections will be relevant for a precise determination of the b quark mixing angles by testing isospin symmetry when measurements of semileptonic rates of charged and neutral B mesons at the few percent level become available. For completeness, we also provide numerical values of radiative corrections in the three-body region of the Dalitz plot distributions of these decays. (orig.)

Radiative corrections to e+e- reactions to all orders in α using the renormalization group

International Nuclear Information System (INIS)

Tsai, Y.S.

1983-01-01

Renormalization group technique is used to improve the accuracy of the lowest order radiative corrections in QED. The exponentiation of infrared terms comes automatically. It also leads to exponentiation of the vertex functions. It predicts the existence of conversion of photons into pairs and the result agrees with the Kroll-Wada relation. Kinoshita-Lee-Nauenberg cancellation of mass singularities occurs to all order in α in leading log approximation in the final state if we sum over all the final states. Higher order corrections to the order α 3 asymmetry is shown to be small. The results are used to derive useful formulas for the radiative corrections to processes such as e + e - → μ + μ - , e + e - → μ + μ - γ, e + e - → hadron continuum, e + e - → very narrow resonance such as phi, and e + e - → not very narrow resonance such as Z 0

Radiative corrections to the Coulomb law and model of dense quantum plasmas: Dispersion of longitudinal waves in magnetized quantum plasmas

Science.gov (United States)

Andreev, Pavel A.

2018-04-01

Two kinds of quantum electrodynamic radiative corrections to electromagnetic interactions and their influence on the properties of highly dense quantum plasmas are considered. Linear radiative correction to the Coulomb interaction is considered. Its contribution in the spectrum of the Langmuir waves is presented. The second kind of radiative corrections are related to the nonlinearity of the Maxwell equations for the strong electromagnetic field. Their contribution in the spectrum of transverse waves of magnetized plasmas is briefly discussed. At the consideration of the Langmuir wave spectrum, we included the effect of different distributions of the spin-up and spin-down electrons revealing in the Fermi pressure shift.

The new radiation protection ordinance from the viewpoint of the researcher in nuclear medicine; Die neue Strahlenschutzverordnung aus der Sicht des in der Forschung taetigen Nuklearmediziners

Energy Technology Data Exchange (ETDEWEB)

Reiners, Chr.; Lassmann, M. [Klinik und Poliklinik fuer Nuklearmedizin der Univ. Wuerzburg (Germany)

2002-05-01

After the new radiation protection ordinance has come into effect with July 20th, 2001 the approval process for application of radiation substances or ionizing radiation in medical research changed considerably with respect to the responsibility of the Federal Office for Radiation Protection as the approval authority, the participation of an approved ethic committee, the inclusion of an expert for medical physics for planning and execution of the study as well as stricter regulations for cover clause. On the contrary, existing regulations have been facilitated since the effective dose limit for volunteers has been increased from 10 to 20 mSv and a central procedure for approval of multicenter studies has been introduced. Moreover, the application of radioactive substances or ionizing radiation for research in people without or with restricted legal capacity is no more totally prohibited. At present, changes of the radiation protection ordinance and the atomic law cover clause ordinance with respect to medical research are in discussion. (orig.) [German] Nach In-Kraft-Treten der neuen Strahlenschutzverordnung vom 20.07.2001 ergeben sich wesentliche Aenderungen des Genehmigungsverfahrens fuer die Anwendung radioaktiver Stoffe oder ionisierender Strahlung in der medizinischen Forschung bezueglich der Zustaendligkeit des Bundesamts fuer Strahlenschutz als Genehmigungsbehoerde, der Einschaltung einer akkreditierten Ethikkommission, der Hinzuziehung eines Medizinphysik-Experten bei der Studien-Planung und -Anwendung sowie verschaerfter Regelungen zur Deckungsvorsorge. Eine gewisse Erleichterung bisher bestehender Regelungen ist in der Erhoehung des Grenzwerts der effektiven Dosis fuer Probanden von 10 auf 20 mSv sowie dem zentralen Genehmigungsverfahren fuer Multizenter-Studien zu sehen. Ausserdem ist eine Anwendung radioaktiver Stoffe oder ionisierender Strahlung in der Forschung an geschaeftsunfaehigen und beschraenkt geschaeftsfaehigen Probanden nicht mehr voellig

Radiative corrections in SU2 x U1 LEP/SLC

International Nuclear Information System (INIS)

Lynn, B.W.; Peskin, M.E.; Stuart, R.G.

1985-06-01

We show the sensitivity of various experimental measurements to one-loop radiative corrections in SU 2 x U 1 . Models considered are the standard GSW model as well as extensions of it which include extra quarks and leptons, SUSY and certain technicolor models. The observation of longitudinal polarization is a great help in seeing these effects in asymmetries in e + e - → μ + μ - , tau + tau - on Z 0 resonance. 25 refs., 22 figs., 10 tabs

Surface terms and radiative corrections to the VVA triangle diagram

International Nuclear Information System (INIS)

Chowdhury, A.M.; McKeon, G.

1986-01-01

The two-loop radiative corrections to the divergence of the axial-vector current are analyzed in the context of spinor electrodynamics. It is found that the arbitrariness that occurs in the relevant Feynman diagrams due to the appearance of surface terms associated with linearly divergent integrals is sufficient to ensure that at two-loop order the Ward identity can be satisfied, irrespective of how the divergences that occur are parametrized. This indicates that the Adler-Bardeen theorem is satisfied

Pratiques tutorales correctives via Internet : le cas du français en première ligne Corrective feedback via Internet by tutor trainees: a case study

Directory of Open Access Journals (Sweden)

Katerina Zourou

2007-06-01

Full Text Available Dans le cadre d’un projet de télécollaboration, des étudiants en master professionnel FLE ont encadré à distance des apprenants de français espagnols. Cet encadrement a consisté à concevoir des tâches, à accompagner la réalisation de ces tâches à travers des plateformes de formation en ligne et plus largement à communiquer (de manière asynchrone avec les étudiants distants. Les tâches demandant le plus souvent une production ouverte, tantôt écrite, tantôt orale, l’un des problèmes auxquels ont été confrontés les futurs enseignants de FLE est celui de la correction des énoncés produits : c’est à cette dimension évaluative de la communication médiatisée, qui constitue une forme d’aide (humaine à l’apprentissage, que s’intéresse cet article. La question sous-jacente est celle de la spécificité d’une relation à la fois instrumentée, en mode asynchrone et entièrement à distance quant à ce problème de l’évaluation des productions langagières.Within a telecollaborative project, master’s students in teaching French as a foreign language tutored Spanish learners of French at a distance. This tutoring experience consisted in designing tasks, in supporting Spanish students while they were fulfilling these tasks, and more generally in communicating (asynchronously with these distance students. As most tasks asked for an open written or oral output, tutors had to give feedback and to correct Spanish students. This paper focuses on these corrective feedbacks, which represent a specific form of learning support. The main issue deals with the specificities of corrective feedback when performed in the context of a pedagogic relationship which is carried out fully at a distance and asynchronously with the use of technological tools.

Evaluation of systematic uncertainties caused by radiative corrections in experiments on deep inelastic νsub(l)N-scattering

International Nuclear Information System (INIS)

Bardin, D.Yu.

1979-01-01

Basing on the simple quark-parton model of strong interaction and on the Weinberg-Salam theory compact formulae are derived for the radiative correction to the charged current induced deep inelastic scattering of neutrinos on nucleons. The radiative correction is found to be around 20-30%, i.e., the value typical for deep inelastic lN-scattering. The results obtained are rather different from the presently available estimations of the effect under consideration

The assessment of four different correction models applied to the diffuse radiation measured with a shadow ring using global and normal beam radiation measurements for Beer Sheva, Israel

Energy Technology Data Exchange (ETDEWEB)

Kudish, Avraham I.; Evseev, Efim G. [Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, E D Bergmann Campus, Beer Sheva 84105 (Israel)

2008-02-15

The measurement of the diffuse radiation incident on a horizontal surface, a priori a straightforward task, is fraught with difficulties. It is possible to measure the diffuse radiation by three different techniques: two of which measure it directly and the third indirectly. The most accurate is the indirect one, which is based upon the concurrent measurements of the horizontal global and the normal incidence beam radiation. The disadvantage of this being the relatively expensive tracking system required for measuring the latter. The diffuse radiation can be measured directly with a pyranometer outfitted with either an occulting disk or shadow ring, which prevent the beam radiation from impinging on the pyranometer sensor. The occulting disk can provide accurate measurements of the diffuse radiation but it requires a relatively expensive sun tracking system in the east-west axis. The shadow ring is a stationary device with regard to the east-west axis and blocks the beam radiation component by creating a permanent shadow on the pyranometer sensor. The major disadvantage of the shadow ring is that it also blocks that portion of the diffuse radiation obscured by the shadow ring. This introduces a measurement error that must be corrected to account for that portion of the sky obscured by the shadow band. In addition to this geometric correction factor there is a need to correct for anisotropic sky conditions. Four correction models have been applied to the data for Beer Sheva, Israel and the results have been evaluated both graphically and statistically. An attempt has been made to score the relative performance of the models under different sky conditions. (author)

Prior image constrained scatter correction in cone-beam computed tomography image-guided radiation therapy.

Science.gov (United States)

Brunner, Stephen; Nett, Brian E; Tolakanahalli, Ranjini; Chen, Guang-Hong

2011-02-21

X-ray scatter is a significant problem in cone-beam computed tomography when thicker objects and larger cone angles are used, as scattered radiation can lead to reduced contrast and CT number inaccuracy. Advances have been made in x-ray computed tomography (CT) by incorporating a high quality prior image into the image reconstruction process. In this paper, we extend this idea to correct scatter-induced shading artifacts in cone-beam CT image-guided radiation therapy. Specifically, this paper presents a new scatter correction algorithm which uses a prior image with low scatter artifacts to reduce shading artifacts in cone-beam CT images acquired under conditions of high scatter. The proposed correction algorithm begins with an empirical hypothesis that the target image can be written as a weighted summation of a series of basis images that are generated by raising the raw cone-beam projection data to different powers, and then, reconstructing using the standard filtered backprojection algorithm. The weight for each basis image is calculated by minimizing the difference between the target image and the prior image. The performance of the scatter correction algorithm is qualitatively and quantitatively evaluated through phantom studies using a Varian 2100 EX System with an on-board imager. Results show that the proposed scatter correction algorithm using a prior image with low scatter artifacts can substantially mitigate scatter-induced shading artifacts in both full-fan and half-fan modes.

On the correctness of the thermoluminescent high-temperature ratio (HTR) method for estimating ionization density effects in mixed radiation fields

International Nuclear Information System (INIS)

Bilski, Pawel

2010-01-01

The high-temperature ratio (HTR) method which exploits changes in the LiF:Mg,Ti glow-curve due to high-LET radiation, has been used for several years to estimate LET in an unknown radiation field. As TL efficiency is known to decrease after doses of densely ionizing radiation, a LET estimate is used to correct the TLD-measured values of dose. The HTR method is purely empirical and its general correctness is questionable. The validity of the HTR method was investigated by theoretical simulation of various mixed radiation fields. The LET eff values estimated with the HTR method for mixed radiation fields were found in general to be incorrect, in some cases underestimating the true values of dose-averaged LET by an order of magnitude. The method produced correct estimates of average LET only in cases of almost mono-energetic fields (i.e. in non-mixed radiation conditions). The value of LET eff found by the HTR method may therefore be treated as a qualitative indicator of increased LET, but not as a quantitative estimator of average LET. However, HTR-based correction of the TLD-measured dose value (HTR-B method) was found to be quite reliable. In all cases studied, application of this technique improved the result. Most of the measured doses fell within 10% of the true values. A further empirical improvement to the method is proposed. One may therefore recommend the HTR-B method to correct for decreased TL efficiency in mixed high-LET fields.

Radiation therapy in old patients. Side effects and results of radiation therapy in old patients; Strahlentherapie des alten Patienten. Vertraeglichkeit und Ergebnisse der Strahlentherapie aelterer Personen

Energy Technology Data Exchange (ETDEWEB)

Geinitz, H.; Zimmermann, F.B.; Molls, M. [Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany)

1999-03-01

Background: Despite a growing number of elderly patients receiving radiation therapy little is known about side effects and outcome of irradiation in this section of the population. Methods: In a review article epidemiologic data, aspects of radiation-biology as well as side effects and outcome of radiation therapy of elderly patients are discussed. Results: Cancer incidence rises with age and is exceeding 3.5% for males older than 85 years. With a life expectancy of more than 4 years, curative therapy is indicated even at this age. Furthermore, several retrospective studies indicate that local control and disease-Specific survival after radiation therapy of elderly patients is comparable with that of younger persons. The exception contains elderly patients with grade-III to IV gliomas or with rectal carcinoma who show a reduced survival which is perhaps caused by less aggressive combined treatment (tumor resection). Although some biological and molecular data indicate a rise in radiation sensitivity with growing age like the reduction of the capacity of some DNA-repair enzymes, there is no convincing evidence in animal studies or in retrospective clinical studies that radiation therapy is generally less well tolerated by older individuals. Some age-depending differences in organ toxicities are described in 3 large studies, which evaluate the data of patients who were enrolled in different EORTC-trials: Older patients suffer more of functional mucositis in case of radiation therapy to the head and neck, they have an increased weight loss and a higher frequency of late esophageal damage when irradiated in the thorax, and they show a higher prevalence of sexual dysfunction when treated with radiation therapy to the pelvis. On the other hand younger patients suffer more from acute toxicity like skin damage, nausea, and deterioration of the performance status during pelvic radiotherapy. When discussing the dose intensity of radiation therapy concomitant disease which

A radiative corrections scheme for generation of the lepton masses

International Nuclear Information System (INIS)

Pisano, F.; Pleitez, V.; Tonasse, M.D.

1994-01-01

We consider in the context of 331 model of the electroweak interactions the generation of the lepton masses by introducing a single neutral right-handed singlet in a radiatively corrections scheme. By adding a lepton-baryon number violating term in the Higgs potential, we show that one can have the right mass spectrum for the leptons without introducing a sextet of Higgs fields which is present in the original model. (author) of Higgs fields which is present in the original model. (author)

Effects of Radiation on Germ Cells of Insects: Dominant Lethals, Gamete Inactivation and Gonial-Cell Killing; Effets des rayonnements sur les cellules germinales des insectes: letalite dominante, inactivation des gametes et destruction des cellules des gonades; Vozdejstvie radiatsii na polovye kletki nasekomykh: dominantnye letali, inaktivatsiya gamet i umershchvlenie polovykh kletok; Efectos de las radiaciones sobre las celulas germinales de los insectos: elementos letales dominantes, inactivacion de los gametos y exterminacion de las celulas gonadicas

Energy Technology Data Exchange (ETDEWEB)

Von Borstel, R. C. [Biology Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

1963-09-15

Radiations and chemical mutagens kill cells in numerous ways: by one of several kinds of induced dominant lethality, by a direct inactivation of function as with sperm, and by genetically undefinable types of death which may or may not be related to dominant lethality per se. Also, chemical mutagens appear to exert a curious enhancement of the fertilizing capacity of sperm. The different stages of oflgenesis and spermatogenesis respond with unequal sensitivity to radiation, and individual cells pass through stages conferring as much as a 50-fold difference in sensitivity. Where species of Diptera, Hymenoptera and Coleoptera can be compared, a striking similarity of response to radiation can be observed, both to stage sensitivity and degree of response with dose. The silkworm, Bombyx mori (Lepidoptera), seems to be similar in most respects to representatives of the other orders in response of germ cells to radiation, but differs sharply in types of dominant lethality induced. Species having atypical genetic mechanisms (e.g.,the lecanoid system of Planococcus citri (Hemipt. : Coccidae) are special cases, and their responses to radiation are considerably modified from those of other species. For insect population control by the irradiation-of-male method, dominant lethality is as advantageous in species where matings are multiple as in species where mating occurs once. Sperm inactivation and gonial killing can be regarded as instances of true sterility and are maximally effective only in species where mating occurs once. For most efficient control, doses should be chosen which would induce maximum dominant lethality, minimum sperm inactivation and complete killing of gonial cells. These parameters are simple to determine by gamete viability measurements, irradiated and unirradiated population competition experiments and histological examination of gonia. (author) [French] Les rayonnements et les agents chimiques de mutation detruisent les cellules de nombreuses facons

La correction et la révision de l’écrit en français langue seconde: médiation humaine, médiation informatique Correcting and editing texts written by FSL students: human mediation vs. computer-assisted mediation

Directory of Open Access Journals (Sweden)

Chantal Dion

2003-06-01

Full Text Available L’apprentissage de la correction / révision de l’écrit par les apprenants de français langue seconde peut-elle tirer profit des correcteurs orthographiques et grammaticaux des traitements de texte ou des correcticiels spécialisés ? La nature de la médiation informatique permet-elle aux apprenants de corriger de façon efficace leurs textes et comment se compare-t-elle avec la correction humaine ? Qu’est-ce qui différencie ces deux médiations ? Des textes rédigés par des anglophones ont été soumis aux deux types de corrections, humaine et informatique, soit deux enseignantes ayant vingt ans d’expérience et la correction informatique effectuée par le correcteur orthographique et grammatical de Word et les deux correcticiels canadiens, Le correcteur 101 et Antidote. Les résultats montrent que la nature de ces médiations n’est pas comparable et que la médiation informatique, pour être efficace, nécessite la participation active, intelligente et instruite de l’utilisateur et que les correcticiels ne peuvent pas corriger efficacement des textes d’étudiants de niveau intermédiaire.Can spellcheckers or grammar correctors, be they part of a word processor or stand-alone programs, help FSL students become more adept at correcting or editing the written texts they produce? Does computer-assisted mediation enable learners to correct their work efficiently and how does it compare with human mediation? What differentiates them? Texts written by anglophone students were corrected using both methods, i.e., on the one hand, by two teachers with 20 years experience and, on the other hand, using the specialized tools available with MSWord as well as two Canadian text correction programs, Le Correcteur 101 and Antidote. It turns out that the two methods are of very different natures ; computer-based correction can only give some positive results if the users have received appropriate training enabling them to actively and

Radiative corrections to the charged pion-pair production process {pi}{sup -}{gamma} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -} at low energies

Energy Technology Data Exchange (ETDEWEB)

Kaiser, N.; Petschauer, S. [Technische Universitaet Muenchen, Physik-Department T39, Garching (Germany)

2013-12-15

We calculate the one-photon loop radiative corrections to the charged pion-pair production process {pi}{sup -}{gamma} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -}. In the low-energy region this reaction is governed by the chiral pion-pion interaction. The pertinent set of 42 irreducible photon-loop diagrams is calculated by using the package FeynCalc. Electromagnetic counterterms with two independent low-energy constants k{sub 1} and k{sub 2} are included in order to remove the ultraviolet divergences generated by the photon loops. Infrared finiteness of the virtual radiative corrections is achieved by including soft photon radiation below an energy cut-off {Lambda}. The purely electromagnetic interaction of the charged pions mediated by one-photon exchange is also taken into account. The radiative corrections to the total cross section (in the isospin limit) vary between +10% close to threshold and about -1% at a center-of-mass energy of 7m{sub {pi}}. The largest contribution comes from the simple one-photon exchange. Radiative corrections to the {pi}{sup +}{pi}{sup -} and {pi}{sup -}{pi}{sup -} mass spectra are studied as well. The Coulomb singularity of the final-state interaction produces a kink in the dipion mass spectra. The virtual radiative corrections to elastic {pi}{sup -}{pi}{sup -} scattering are derived additionally. (orig.)

On the radiative corrections α2lnα to the positronium decay rate

International Nuclear Information System (INIS)

Khriplovich, I.B.; Elkhovskij, A.S.

1990-01-01

The radiative corrections ∼α 2 ln α to the positronium decay rate are calculated in the Breit approximation which is shown to be quite adequate for the problem. For orthopositronium the result coincides with the previous one, for parapositronium it differs from the old results. 9 refs

Isospin breaking and radiative corrections in K{sub l4} decays; Brisure d'isospin et corrections radiatives au processus K{sub l4}

Energy Technology Data Exchange (ETDEWEB)

Cuplov, V

2004-04-15

This thesis is dedicated to the impact of electromagnetic corrections on the decays of K{sub l4}. 2 types of electromagnetic contributions have to be considered: first the exchange of virtual photons and secondly the non-perturbative part of meson-photon interactions. We have also considered the effects of isospin breaking. We have shown that the isospin breaking and the electromagnetic corrections affect K{sub l4} decays in the neutral and mixed channels (respectively by 8% and -2%), while the charged channel is unaffected. It also appears that the tree approximation for the computation of the decay rates, is not accurate enough to explain experimental data. In the second part of this work, we give the analytical expressions of the F and G form factors associated with the amplitude of the K{sub l4} process in the charged mode. Infra-red divergencies counterbalance each other in the decay rates calculation when we consider the process K{sub l4{gamma}} where 1 photon is emitted with an energy below the sensitivity of the detector. We have found that the calculation in one loop order represents 75% of the measured value. The impact of radiative corrections is about 0.9% while the isospin breaking effect is about 1.6 per cent.

Implications of QCD radiative corrections on high-pT Higgs searches

International Nuclear Information System (INIS)

Banfi, Andrea; Cancino, Julián

2012-01-01

We discuss the effect of next-to-leading order (NLO) QCD corrections to the Higgsstrahlung process, where the Higgs boson decays to bottom quarks, using a partonic-level fully differential code. First we evaluate the impact of initial- and final-state gluon radiation on the reconstruction of a mass peak with the fat-jet analysis in the boosted regime at the LHC with √(s)=14 TeV as proposed in Butterworth et al. (2008). We then consider the current CMS search strategy for this channel and compare it to the fat-jet procedure at the LHC with √(s)=8 TeV. Both studies show that final-state QCD radiation has a sizeable effect and should be taken properly into account.

Contrôle des circuits auxiliaires des P.F.W. (arret machine 2004/2006, après rénovation de 25 aimants)

CERN Document Server

Ottaviani, J

2006-01-01

Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d'aimant et constituées d'un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et ?pick-up? brasés sur les enroulements principaux). Pendant la variation du champ magnétique de l'aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Chaque année, pendant l'arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre ?pick-up? et isolation des circuits) afin de faire un suivi. Des mesures ont été faites au début du grand arrêt en décembre 2004 afin de définir quels aimants seraient à rénover (l'état des PFW e...

O(α2L2) radiative corrections to deep inelastic ep scattering for different kinematical variables

International Nuclear Information System (INIS)

Bluemlein, J.

1994-03-01

The QED radiative corrections are calculated in the leading log approximation up to O(α 2 ) for different definitions of the kinematical variables using jet measurement, the 'mixed' variables, the double angle method, and a measurement based on θ e and y JB . Higher order contributions due to exponentiation of soft radiation are included. (orig.)

Determination of correction coefficients for quantitative analysis by mass spectrometry. Application to uranium impurities analysis; Recherche des coefficients de correction permettant l'analyse quantitative par spectrometrie de masse. Application a l'analyse d'impuretes dans l'uranium

Energy Technology Data Exchange (ETDEWEB)

Billon, J P [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

1970-07-01

Some of basic principles in spark source mass spectrometry are recalled. It is shown how this method can lead to quantitative analysis when attention is paid to some theoretical aspects. A time constant relation being assumed between the analysed solid sample and the ionic beam it gives we determined experimental relative sensitivity factors for impurities in uranium matrix. Results being in fairly good agreement with: an unelaborate theory on ionization yield in spark-source use of theoretically obtained relative sensitivity factors in uranium matrix has been developed. (author) [French] Apres avoir rappele quelques principes fondamentaux regissant la spectrometrie de masse a etincelles, nous avons montre que moyennant un certain nombre de precautions, il etait possible d'utiliser cette methode en analyse quantitative. Ayant admis qu'il existait une relation constante dans le temps entre l'echantillon solide analyse et le faisceau ionique qui en est issu, nous avons d'abord entrepris de determiner des coefficients de correction experimentaux pour des matrices d'uranium. Les premiers resultats pratiques semblant en accord avec une theorie simple relative au rendement d'ionisation dans la source a etincelles, nous avons etudie la possibilite d'appliquer directement les coefficients theoriques ainsi definis, l'application etant toujours faite sur des matrices d'uranium. (auteur)

Radiative corrections for associated ZH production at future e+e- colliders

International Nuclear Information System (INIS)

Kniehl, B.A.

1991-11-01

The ZHfanti f four-point function is calculated in the one-loop approximation of the Standard Model and full analytic results are presented. The loop contributions due to both light and new heavy fermions are inspected in detail. The dominant mechanisms of Higgs-boson production from fermions are compared. The effect of radiative corrections on the cross section of fanti f→ZH including bremsstrahlung is studied. The spectrum of hard bremsstrahlung is integrated analytically. The implications for Higgs-boson searches at future e + e - colliders in the energy range 200 GeV≤√s≤1.5 TeV, which includes both LEP 2 and the Next Linear Collider, are analyzed. At √s=500 GeV, for instance, weak corrections in the modified on-mass-shell scheme vary between -2% and +7%, depending on the actual values of the Higgs-boson and top-quark masses. Electromagnetic corrections strongly reduce the cross section close to the ZH-production threshold, while they may considerably enhance it far above threshold. (orig.)

Synchronous atmospheric radiation correction of GF-2 satellite multispectral image

Science.gov (United States)

Bian, Fuqiang; Fan, Dongdong; Zhang, Yan; Wang, Dandan

2018-02-01

GF-2 remote sensing products have been widely used in many fields for its high-quality information, which provides technical support for the the macroeconomic decisions. Atmospheric correction is the necessary part in the data preprocessing of the quantitative high resolution remote sensing, which can eliminate the signal interference in the radiation path caused by atmospheric scattering and absorption, and reducting apparent reflectance into real reflectance of the surface targets. Aiming at the problem that current research lack of atmospheric date which are synchronization and region matching of the surface observation image, this research utilize the MODIS Level 1B synchronous data to simulate synchronized atmospheric condition, and write programs to implementation process of aerosol retrieval and atmospheric correction, then generate a lookup table of the remote sensing image based on the radioactive transfer model of 6S (second simulation of a satellite signal in the solar spectrum) to correct the atmospheric effect of multispectral image from GF-2 satellite PMS-1 payload. According to the correction results, this paper analyzes the pixel histogram of the reflectance spectrum of the 4 spectral bands of PMS-1, and evaluates the correction results of different spectral bands. Then conducted a comparison experiment on the same GF-2 image based on the QUAC. According to the different targets respectively statistics the average value of NDVI, implement a comparative study of NDVI from two different results. The degree of influence was discussed by whether to adopt synchronous atmospheric date. The study shows that the result of the synchronous atmospheric parameters have significantly improved the quantitative application of the GF-2 remote sensing data.

Neutron Dosimetry and Irradiation of Solids; Dosimetrie des neutrons et irradiation des solides

Energy Technology Data Exchange (ETDEWEB)

Perriot, G; Schmitt, A P [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

1962-07-01

Results of work at C.E.A. from 1958 to 1960 are reviewed. The possibilities offered by classical dosimetry methods are discussed. The tests which led to the utilization, for fast neutron dosimetry, of resistivity variations induced in solid W by such neutrons are described. Experimental W irradiation results led to a definition of neutron efficiency which describes the relations between neutron energy and their effects on materials. Possibilities offered by detectors which make use of radiation damage and are sensitive to neutrons at keV energies were explored. In other work, the principal French reactors were classified according to their ability to produce damage in materials such as W. (authors) [French] Dans ce rapport on a presente les resultats essentiels de travaux qui ont ete effectues de 1958 a 1980 par des chercheurs du CEA issus de differents services. En meme temps qu'une revue des possibilites offertes a l'epoque par les methodes classiques de dosimetrie (utilisation des detecteurs par activation), on a decrit les essais qui devaient permettre d'utiliser, a la dosimetrie les neutrons rapides, les variations de resistivite qu'ils creent dans un corps solide (tungstene). L'irradiation du tungstene a montre l'importance qu'il y avait a definir 'l'efficacite' des neutrons, c'est-a-dire leur aptitude plus ou moins grande, selon leur energie, a creer des defauts dans les materiaux. L'efficacite d'un emplacement d'irradiation se trouvant liee au spectre neutronique, on a vu les difficultes qu'il y avait a utiliser les detecteurs par activation des qu'on n'avait plus affaire a un spectre en 1/E ou de fission et on a pu entrevoir les possibilites offertes par les detecteurs utilisant la creation des defauts qui repondent a tous les neutrons d'energies, superieures a quelques keV. Enfin, on a classe les principaux types de Piles Francaises selon leur aptitude a creer plus ou moins rapidement des dommages dans des materiaux comme le tungstene. (auteur)

Nonuniformity correction of infrared cameras by reading radiance temperatures with a spatially nonhomogeneous radiation source

International Nuclear Information System (INIS)

Gutschwager, Berndt; Hollandt, Jörg

2017-01-01

We present a novel method of nonuniformity correction (NUC) of infrared cameras and focal plane arrays (FPA) in a wide optical spectral range by reading radiance temperatures and by applying a radiation source with an unknown and spatially nonhomogeneous radiance temperature distribution. The benefit of this novel method is that it works with the display and the calculation of radiance temperatures, it can be applied to radiation sources of arbitrary spatial radiance temperature distribution, and it only requires sufficient temporal stability of this distribution during the measurement process. In contrast to this method, an initially presented method described the calculation of NUC correction with the reading of monitored radiance values. Both methods are based on the recording of several (at least three) images of a radiation source and a purposeful row- and line-shift of these sequent images in relation to the first primary image. The mathematical procedure is explained in detail. Its numerical verification with a source of a predefined nonhomogeneous radiance temperature distribution and a thermal imager of a predefined nonuniform FPA responsivity is presented. (paper)

Detection of high energy gamma radiations with liquid rare gases as scintillators; Detection des rayonnements Gamma de grande energie avec les gaz rares liquides comme scintillateurs

Energy Technology Data Exchange (ETDEWEB)

Ho, Phan Xuan

1965-11-25

This research thesis reports the study of a sensor based on a liquid scintillator for the detection of high energy (10 to 30 MeV) gamma radiations. The scintillator is a liquefied argon or xenon rare gas. The author first studies the process of energy transfer from the particle to the sensing medium. He addresses the different involved elements and phenomena: electromagnetic radiations (Compton Effect, photoelectric effect, pair production, and total gamma absorption), charged particles (braking radiation, collisions) and application to gamma spectrometry. He describes and discusses the scintillation mechanisms (scintillation of organic and inorganic materials), the general characteristics of scintillators (impurities, converters), and then reports the practical realisation of the sensor. Results are presented and discussed [French] Dans ce travail, nous nous proposons d'etudier une technique. Il s'agit d'un detecteur a scintillateur liquide pour la detection des rayonnements gamma energiques (10 a 30 MeV). Le scintillateur utilise est un gaz rare liquefie argon ou xenon. Nous examinerons d'abord les processus de transfert de l'energie de la particule au milieu detecteur puis les mecanismes de scintillation en general pour pouvoir exploiter au mieux les phenomenes favorables. Nous presenterons ensuite la realisation pratique du detecteur. Ses qualites (et defauts) trouveront leur place dans la fin de ce memoire. Bien qu'a l'heure actuelle, par la methode de Kyropoulos, on puisse faire pousser des gros cristaux d'iodure de sodium, l'utilisation des 'gaz rares' liquefies comme scintillateurs est, grace a la brievete de la scintillation, tres utile lorsqu'on recherche un fort taux de comptage (jusqu'a 10 impulsions par seconde) ou lorsqu'on veut resoudre certains problemes de coincidence. Les cristaux NaI(Tl) de grandes dimensions sont d'un montage facile mais leur manipulation requiert beaucoup de precautions du fait qu'ils supportent tres mal les chocs thermiques

Radiation Disinfestation of Grain and Seeds; Radiodesinsection des Cereales et des Semences; Obezzarazhivanie zerna i semyan s pomoshch'yu oblucheniya; Desinfestacion de Granos y Semillas por Irradiacion

Energy Technology Data Exchange (ETDEWEB)

Golumbic, C.; Davis, D. F. [Market Quality Research Division, Agricultural Research Service, United States Department of Agriculture, Hyattsville, MD (United States)

1966-11-15

Current interest in radiation treatment of grain and seeds mainly revolves about its efficacy for control of insect infestations in these products. The recent literature on this subject is reviewed and gaps still existing in the fundamental and practical knowledge of radiation disinfestation.are pointed out. Research programmes in the United States Department of Agriculture that are under way, or planned for the immediate future, are discussed in detail. Current studies are being directed toward establishing minimum effective doses for sexual sterilization and mortality, influence of environmental factors on dose requirements, and potential for the development of biological resistance. In May 1966 the scope of the work expanded as a new grain products irradiator became operative and applied studies were initiated. An integral part of this, research is a study of the effect of irradiation on the quality of food and feed grains and on cereal products, at the doses for both insect control and fungal disinfection. This paper examines critically the results of research in this area and estimates future research, needs. (author) [French] A'.l'heure actuelle, l'interet que suscite le traitement par les rayonnements des cereales et des semences est du avant tout a son efficacite pour la desinsection. Les auteurs analysent les recentes publications dans ce domaine et. signalent les lacunes, qui subsistent encore dans les connaissances fondamentales ou pratiques relatives a la radiodesinsection, ' Ils examinent en detail les programmes de recherches du Departement de l'agriculture des Etats-Unis qui sont actuellement mis.en oeuvre ou projetes pour l'avenir immediat. Les etudes actuelles concernent la determination de la dose minimale necessaire pour la sterilisation sexuelle et de la dose mortelle, l'influence des facteurs ambiants sur les doses requises, et les possibilites de developpement de la resistance biologique. En mai 1966, les travaux se sont elargis a la suite de

De la conception à la sûreté des barrages de correction torrentielle From design to safety and reliability assessment of torrent control dams

Directory of Open Access Journals (Sweden)

Jean-Marc Tacnet et Didier Richard

2010-09-01

Full Text Available Dans les bassins versants de montagne, les phénomènes torrentiels, de par leur caractère brutal et très rapide, présentent des risques importants pour les biens, les personnes et l'environnement. Afin de réduire ces risques, des mesures structurelles ont été mises en place, comme la construction de barrages de correction torrentielle. Mais comment caractériser l'état et l'efficacité de ces ouvrages ? Assurent-ils un niveau de sécurité suffisant ? Les auteurs s'intéressent ici aux principes de conception et à l'analyse des pathologies et défaillances de ce type d'ouvrages.To reduce risk level in mountain rivers floods prone areas, structural defence works are still mandatory. The global efficiency of those protection strategies depends on both functional and structural approaches. This article first presents main types and functions of torrent control dams. Afterwards, it describes the design and building requirements with references to the main failure situations that could be encountered. This technical background is finally identified as a basis for danger and risk analysis that are going to become mandatory for some categories of torrent control dams.

The health physics of installations for decladding irradiated fuels or for handling radio-elements at Marcoule; La radioprotection des installations de degainage des combustibles irradies et des radio-elements a Marcoule

Energy Technology Data Exchange (ETDEWEB)

Chassany, J; Guillermin, P; Mallet, P [Commissariat a l' Energie Atomique, Centre de Production de Plutonium de Marcoule, 30 - Chusclan (France)

1966-07-01

Radiation protection practices for handling reactor fuel elements are described. Elements of considerable specific radioactivity are handled under water. A study was made of water filtration and of ventilation in the building. The installations are divided up into zones depending on the radioactive risks, and the radiation level atmospheric contamination are the object of a systematic control at various points. A description is given of all aspects of health physics which have been encountered during six years: storage, transfer of radioactive material; decladding, rolling, waste disposal, specialized operations, installations in operation and at rest, and transport. In spite of the gradual increase in the activity of these installations, the total doses received by the personnel have hardly altered and the number of cases of physical contamination has diminished. (authors) [French] Dans ces installations, se manipulent sous l'eau des elements a radioactivite specifique considerable. La filtration de l'eau, la ventilation ont ete particulierement etudiees. L'ensemble a ete divise en lieux classes en fonction des risques radioactifs et des appareils controlent en permanence l'irradiation et la contamination atmospherique en certains points. Tous les aspects de la radioprotection resultant de six annees d'experience relatifs: au stockage, au deconteneurage, au degainage, au laminage, a l'evacuation des residus, aux travaux particuliers, installations en marche et a l'arret, et aux transports sont successivement decrits. Malgre l'accroissement progressif de l'activite de cet ensemble, les doses integrees par le personnel n'ont pratiquement pas augmente et le nombre des cas de contamination corporelle a diminue. (auteurs)

Technique and radiation dose of conventional X-rays and computed tomography of the sacroiliac joint; Technik und Strahlendosis konventioneller Roentgenaufnahmen und Computertomographie des Sakroiliakalgelenks

Energy Technology Data Exchange (ETDEWEB)

Jurik, A.G. [Department of Radiology R, Aarhus Kommunehospital (Denmark)

2004-03-01

Anterior-posterior (a.p.) or posterior-anterior X-rays of the sacroiliac joint, sometimes supplemented by a transverse view, have been the method of choice for diagnosis of patients suspected of having sacroiliitis. The sensitivity and specificity of conventional X-rays are relatively low, which can delay the diagnosis of sacroiliitis. Computed tomography (CT) is superior to conventional X-rays for diagnosis of sacroiliitis, but does emit a relatively higher dose of radiation. For this reason, particularly for females, CT should be optimized by employing semi-coronal planes, which require a lower radiation dose than axial planes. CT in a semi-coronal plane causes minimal radiation to the ovaries, and the effective radiation dose for women might even be lower than with conventional AP X-rays. Therefore, for suspected sacroiliitis in young women, CT in the semi-coronal plane is the preferred imaging method with respect to diagnostics and radiation protection when magnetic resonance imaging (MRI) is not available. Male gonads can be protected from radiation doses in conventional X-rays, and CT as the primary imaging method can only be justified in these cases because of its better diagnostic capabilities. Due to the lack of inherent risk factors, MRI is superior to CT for diagnostics since it provides images of inflammatory signs in addition to joint destruction. Thus, when available, MRI should be given preference for diagnosis of sacroiliitis. (orig.) [German] Roentgenaufnahmen des Sakroiliakalgelenks im anterior-posterioren bzw. posterior-anterioren Strahlengang, gelegentlich ergaenzt durch die Schraegaufnahme, sind seit vielen Jahren die Methode der Wahl fuer die Diagnostik bei Patienten mit Verdacht auf Sakroiliitis. Die Sensitivitaet und Spezifitaet des konventionellen Roentgens sind relativ niedrig, was die Diagnose der Sakroiliitis verzoegern koennte. Die Computertomographie (CT) ist dem konventionellen Roentgen fuer die Diagnostik der Sakroiliitis ueberlegen

Futur d'une infrastructure de correction automatisée : CodeGradX

OpenAIRE

Queinnec , Christian; Pons , Olivier

2016-01-01

Cet article évoque quelques expériences et nouvelles idées au-tour d'une infrastructure de correction automatisée de programmes. CodeGradX est une infrastructure de correction automatisée de programmes. Elle est en service depuis 2008 (initialement sous le nom de FW4EX) et a depuis corrigé plus de 150 000 soumissions d'étudiants à des exercices principalement en Scheme, utilitaires d'Unix, JavaScript mais aussi en C, Octave, O'Caml, Python sans oublier les compétitions annuelles des Journées ...

Nuclear safety and radiation protection report of the Saint-Laurent-des-Eaux nuclear facilities - 2011

International Nuclear Information System (INIS)

2012-01-01

This safety report was established under the article 21 of the French law no. 2006-686 of June 13, 2006 relative to nuclear safety and information transparency. It presents, first, the facilities of the Saint-Laurent-des-Eaux nuclear power plant (Saint-Laurent-Nouan (FR)): 2 partially dismantled graphite-gas reactors and a graphite sleeves storage silo (INB 46 and 74), and 2 PWR reactors in operation (INB 100). Then, the nuclear safety and radiation protection measures taken regarding the facilities are reviewed: nuclear safety definition, radiation protection of intervening parties, safety and radiation protection improvement paths, crisis management, external and internal controls, technical situation of facilities, administrative procedures in progress. The incidents and accidents which occurred in 2011, are reported as well as the radioactive and non-radioactive (chemical, thermal) effluents discharge in the environment. Finally, The radioactive materials and wastes generated by the facilities are presented and sorted by type of waste, quantities and type of conditioning. Other environmental impacts (noise, microbial proliferation in cooling towers) are presented with their mitigation measures. Actions in favour of transparency and public information are presented as well. The document concludes with a glossary and a list of recommendations from the Committees for health, safety and working conditions. (J.S.)

Nuclear safety and radiation protection report of the Saint-Laurent-des-Eaux nuclear facilities - 2010

International Nuclear Information System (INIS)

2011-06-01

This safety report was established under the article 21 of the French law no. 2006-686 of June 13, 2006 relative to nuclear safety and information transparency. It presents, first, the facilities of the Saint-Laurent-des-Eaux nuclear power plant (Saint-Laurent-Nouan (FR)): 2 partially dismantled graphite-gas reactors and a graphite sleeves storage silo (INB 46 and 74), and 2 PWR reactors in operation (INB 100). Then, the nuclear safety and radiation protection measures taken regarding the facilities are reviewed: nuclear safety definition, radiation protection of intervening parties, safety and radiation protection improvement paths, crisis management, external and internal controls, technical situation of facilities, administrative procedures in progress. The incidents and accidents which occurred in 2010, are reported as well as the radioactive and non-radioactive (chemical, thermal) effluents discharge in the environment. Finally, The radioactive materials and wastes generated by the facilities are presented and sorted by type of waste, quantities and type of conditioning. Other environmental impacts (noise, microbial proliferation in cooling towers) are presented with their mitigation measures. Actions in favour of transparency and public information are presented as well. The document concludes with a glossary and a list of recommendations from the Committees for health, safety and working conditions. (J.S.)

Left-right gauge symmetry breaking by radiative corrections in supergravity

International Nuclear Information System (INIS)

Moxhay, P.; Yamamoto, K.

1984-01-01

A supersymmetric SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) gauge theory coupled to N = 1 supergravity is investigated. The scale of left-right gauge symmetry breaking is determined as Msub(R) proportional Msub(P) esup(-1/α) by radiative corrections through the logarithmic evolution of soft supersymmetry breakings. SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) may be embedded in SO(10) grand unification. Cosmological implications intrinsic to the present model are also discussed, which may give a constraint Msub(R) approx.= 10 9-12 GeV. (orig.)

Recent Developments in the Theory of Mechanisms in Radiation Chemical Processes; Developpements recents dans la theorie des mecanismes des reactions radiochimiques; Poslednie dostizheniya v teorii mekhanizmov radiatsionno-khimicheski kh protsessov; Adelantos recientes en la interpretacion teorica del mecanismo de los procesos radioquimicos

Energy Technology Data Exchange (ETDEWEB)

Roberts, R. [U.K.A.E.A., Wantage Research Laboratory, Berks (United Kingdom)

1963-11-15

Recent developments in the mechanisms of radiation-initiated chemical reactions are reviewed. The role of ion molecule processes is reviewed, with particular reference to the radiation chemistry of methane. In this system, the existence of reactions of excited molecules, in addition to ionic processes is deduced. It is shown that, in the radiolysis of methane, unsaturated hydrocarbons play a considerable part in the mechanism of reaction. Developments in ionic polymerization and also polymerization under heterogenous conditions are reviewed. The importance of reactant purity, and also cleanliness of reaction vessels is discussed. The effect of an applied external potential in solid state polymerization is briefly reviewed. The importance of free-radical processes to radiation chemists is considered in the light of the Dow process for the production of ethyl bromide. (author) [French] L'auteur examine les resultats recents obtenus dans l'etude des mecanismes des reactions chimiques radio-induites. Il etudie l'importance des reactions ion-molecule, en considerant tout particulierement la radio-chimie due methane. Il en deduit qu'il existe dans ce systeme, outre les phenomenes ioniques, des reactions de molecules excitees. il montre que les hydrocarbures non satures jouent un role considerable dans la radiolyse du methane. Il passe en revue les resultats obtenus dans la polymerisation ionique ainsi que dans la polymerisation dans des conditions heterogenes. Il insiste sur l'importance de la purete des reactifs ainsi que sur la proprete des recipients. En meme temps, il examine brievement l'effet d'un potentiel exterieur sur la polymerisation a l'etat solide. Il signale l'importance radiochimique des reactions fondees sur des radicaux liebre, libres sous l'angle du procede Dow pour la production de bromure d'ethyle. (author) [Spanish] El autor examina los recientes progresos realizados en el estudio de los mecanismos de las reacciones quimicas radioinducidas. Sedala la

Supersymmetric electroweak radiative corrections to e+e-→W+W-. III

International Nuclear Information System (INIS)

Alam, S.

1994-01-01

This is the third of a series of three papers in which we give a complete analysis of one loop quantum corrections to the W pair production in the context of supersymmetric electroweak theory. We adopt the on-shell-mass subtraction scheme of Sakakibara. In this paper we concentrate mainly on the one loop corrections to the differential cross section arising from the box diagrams. Details of the relevant analytic results are given. We also present our results for the total radiative corrections and wherever possible compare the QFD part of our calculation with previous work. We find a change of approximately 3%--4% in the differential cross section if the Higgs boson mass is varied from 10 GeV to 500 GeV. The differential cross section varies approximately 8% if the top mass is varied between 40 GeV and 150 GeV. Our results for the dependence of the differential cross section on the Higgs boson and top quark are in agreement with Bohm et al. In the context of the SM we find moderate corrections at CERN LEP II energies. We find the percentage (with respect to the tree-level) virtual loop corrections arising from the box diagrams (considered in this paper) due to the addition of SUSY particles varies approximately from 0.18% to -5.67%. As a comparison the percentage virtual corrections due to the box diagrams in the SM varies typically from 0.89% to 8.3%. The SM total percentage virtual loop corrections varies typically from 17.4% to 19%. The above comparison is made at the same center-of-mass energy (200 GeV). The first percentage in this comparison is for center-of-mass angles of 10 degree, the second being at 90 degree. Adding all the corrections up we find that the addition of the supersymmetric particles tends to increase the percentage one loop corrections on the order of 6%--8% provided the photino is kept light. With an accurate measurement at LEP II, one can in principle detect such a deviation away from the standard model

Radiative corrections in K{yields}{pi}l{sup +}l{sup -} decays

Energy Technology Data Exchange (ETDEWEB)

Kubis, Bastian; Schmidt, Rebekka [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany)

2010-11-15

We calculate radiative corrections to the flavor-changing neutral current process K{yields}{pi}l {sup +}l{sup -}, both for charged and neutral kaon decays. While the soft-photon approximation is shown to work well for the muon channels, we discuss the necessity of further phase space cuts with electrons in the final state. It is also shown how to transfer our results to other decays such as {eta}{yields}{gamma}l{sup +} l{sup -} or {omega}{yields}{pi}{sup 0}l{sup +}l{sup -}. (orig.)

Evaluation d’une grille de supervision des laboratoires des leishmanioses cutanées au Maroc

Science.gov (United States)

El Mansouri, Bouchra; Amarir, Fatima; Hajli, Yamina; Fellah, Hajiba; Sebti, Faiza; Delouane, Bouchra; Sadak, Abderrahim; Adlaoui, El Bachir; Rhajaoui, Mohammed

2017-01-01

Introduction Afin d’évaluer une grille de contrôle standardisée de laboratoire de diagnostic des leishmanioses, comme nouveau outil de supervision. Méthodes Un essai pilote a été pratiqué sur sept laboratoires provinciaux, appartenant à quatre provinces au Maroc, en suivant l’évolution de leurs performances tous les deux ans, entre l’année 2006 et 2014. Cette étude détaille la situation des laboratoires provinciaux avant et après la mise en œuvre de la grille de supervision. Au total vingt et une grille sont analysées. Résultats En 2006, les résultats ont montré clairement une insuffisance des performances des laboratoires: besoin en formation (41.6%), personnel pratiquant le prélèvement cutané (25%), pénurie en matériels et réactifs (65%), gestions documentaire et local non conformes (85%). Différentes actions correctives ont été menées par le Laboratoire National de Référence des Leishmanioses (LNRL) durant la période d’étude. En 2014, le LNRL a enregistré une nette amélioration des performances des laboratoires. Les besoins en matière de formation, qualité du prélèvement, dotation en matériels et réactifs ont été comblés et une coordination efficace s’est établie entre le LNRL et les laboratoires provinciaux. Conclusion Ceci montre l'efficacité de la grille comme outil de supervision de grande qualité, et comme pierre angulaire de tout progrès qui doit être obtenu dans les programmes de lutte contre les leishmanioses. PMID:29187922

Efficiency and attenuation correction factors determination in gamma spectrometric assay of bulk samples using self radiation

International Nuclear Information System (INIS)

Haddad, Kh.

2009-02-01

Gamma spectrometry forms the most important and capable tool for measuring radioactive materials. Determination of the efficiency and attenuation correction factors is the most tedious problem in the gamma spectrometric assay of bulk samples. A new experimental and easy method for these correction factors determination using self radiation was proposed in this work. An experimental study of the correlation between self attenuation correction factor and sample thickness and its practical application was also introduced. The work was performed on NORM and uranyl nitrate bulk sample. The results of proposed methods agreed with those of traditional ones.(author)

Radiative corrections to e+e- → W+W- in the Weinberg model

International Nuclear Information System (INIS)

Lemoine, M.E.

1979-01-01

The author summarizes the Weinberg model and then gives the lowest order cross section for e + e - → W + W - . The various radiative corrections are then dealt with and the method used to compute them outlined. Bremsstrahlung and infrared divergences are discussed together with the renormalization procedure. The Ward identities are then summarized. The leading terms of the amplitude in the limit of large Higgs mass are discussed and the results presented. (Auth.)

Absolute measurement of {beta} emitters with a 4 {pi} counter; Mesure absolue des emetteurs {beta} au compteur 4 {pi}

Energy Technology Data Exchange (ETDEWEB)

Le Gallic, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-06-15

The object of this work is to investigate the conditions under which the activity of {beta}-emitting radionuclides may be measured with a maximum of precision, and as a result to study the relevant corrections. The various problems relating to activity measurements with a 4 {pi} counter have been examined successively: - comparison of 4 {pi}, GM and proportional counters; - study of the preparation of sources; - corrections on the counting of sources; - self-absorption; - correction for absorption. The precision obtained on these measurements varies from 1.2 to 3 per cent, with the result that the 4 {pi} counter can be considered a very satisfactory calibration instrument. (author) [French] Le but de ce travail est de rechercher les conditions permettant d'obtenir avec le maximum de precision, la mesure de l'activite des radionuclides se desintegrant par emission et par consequent d'etudier les corrections qui s'y rapportent. Nous avons examine successivement les differents problemes se rapportant aux mesures d'activite au compteur 4 {pi}: - Comparaison des compteurs 4 {pi}, GM et proportionnel; - etude de la preparation des sources; - corrections sur la numeration des sources; - auto-absorption; - correction d'absorption. La precision obtenue dans ces mesures, variant de 1,2 a 3 pour cent, on peut donc considerer le compteur 4 {pi} comme un instrument d'etalonnage tres satisfaisant. (auteur)

Absolute measurement of {beta} emitters with a 4 {pi} counter; Mesure absolue des emetteurs {beta} au compteur 4 {pi}

Energy Technology Data Exchange (ETDEWEB)

Le Gallic, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-06-15

The object of this work is to investigate the conditions under which the activity of {beta}-emitting radionuclides may be measured with a maximum of precision, and as a result to study the relevant corrections. The various problems relating to activity measurements with a 4 {pi} counter have been examined successively: - comparison of 4 {pi}, GM and proportional counters; - study of the preparation of sources; - corrections on the counting of sources; - self-absorption; - correction for absorption. The precision obtained on these measurements varies from 1.2 to 3 per cent, with the result that the 4 {pi} counter can be considered a very satisfactory calibration instrument. (author) [French] Le but de ce travail est de rechercher les conditions permettant d'obtenir avec le maximum de precision, la mesure de l'activite des radionuclides se desintegrant par emission et par consequent d'etudier les corrections qui s'y rapportent. Nous avons examine successivement les differents problemes se rapportant aux mesures d'activite au compteur 4 {pi}: - Comparaison des compteurs 4 {pi}, GM et proportionnel; - etude de la preparation des sources; - corrections sur la numeration des sources; - auto-absorption; - correction d'absorption. La precision obtenue dans ces mesures, variant de 1,2 a 3 pour cent, on peut donc considerer le compteur 4 {pi} comme un instrument d'etalonnage tres satisfaisant. (auteur)

[Radiometers performance attenuation and data correction in long-term observation of total radiation and photosynthetically active radiation in typical forest ecosystems in China].

Science.gov (United States)

Zhu, Zhi-Lin; Sun, Xiao-Min; Yu, Gui-Rui; Wen, Xue-Fa; Zhang, Yi-Ping; Han, Shi-Jie; Yan, Jun-Hua; Wang, Hui-Min

2011-11-01

Based on the total radiation and photosynthetically active radiation (PAR) observations with net radiometer (CNR1) and quantum sensor (Li-190SB) in 4 ChinaFLUX forest sites (Changbaishan, Qianyanzhou, Dinghushan, and Xishuangbanna) in 2003-2008, this paper analyzed the uncertainties and the radiometers performance changes in long-term and continuous field observation. The results showed that the 98% accuracy of the total radiation measured with CNR1 (Q(cNR1)) could satisfy the technical criterion for the sites except Xishuangbanna where the Q(CNR1) was averagely about 7% lower than Q(CM11), the radiation measured with high accuracy pyranometer CM11. For most sites, though the temperature had definite effects on the performance of CNR1, the effects were still within the allowable range of the accuracy of the instrument. Besides temperature, the seasonal fog often occurred in tropical rain forests in Xishuangbanna also had effects on the performance of CNR1. Based on the long-term variations of PAR, especially its ratio to total radiation in the 4 sites, it was found that quantum sensor (Li-190SB) had obvious performance attenuation, with the mean annual attenuation rate being about 4%. To correct the observation error caused by Li-190SB, an attempt was made to give a post-correction of the PAR observations, which could basically eliminate the quantum sensor's performance attenuation due to long-term field measurement.

Calculation of higher order radiation corrections to beta decay of hyperons in the Glashow-Weinberg-Salam theory

International Nuclear Information System (INIS)

Margaritisz, Tanaszisz

1984-01-01

The Glashow-Weinberg-Salam theory of unified electromagnetic and weak interactions, believed to be the correct quantum theory of these interactions, possesses the great advantage of being renormable. Thus the perturbation theory is applicable to calculate the radiative corrections of the tree-graph results. The present paper describes the detailed calculation of one-loop corrections to beta decay of hyperons. After defining the theory and fixing the gauge and renormalization conventions, the equations of weak and electromagnetic one-loop corrections are derived. Numerical evaluation of the equations was helped by algebraic and integrator computer codes. The results are directly comparable to experimental data. (D.Gy.)

Higher-order radiative corrections for b b ¯→H-W+

Science.gov (United States)

Kidonakis, Nikolaos

2018-02-01

I present higher-order radiative corrections from collinear and soft-gluon emission for the associated production of a charged Higgs boson with a W boson. The calculation uses expressions from resummation at next-to-leading-logarithm accuracy. From the resummed cross section I derive analytical formulas at approximate next-to-next-to-leading order and next-to-next-to-next-to-leading order. Total cross sections are presented for the process b b ¯→H-W+ at various LHC energies. The transverse momentum and rapidity distributions of the charged Higgs boson are also calculated.

On the radiative corrections of deep inelastic scattering of muon neutrino on nucleon

International Nuclear Information System (INIS)

So Sang Guk

1986-01-01

The radiative corrections of deep inelastic scattering process VΜP→ ΜN are considered. Matrix element which takes Feynman one photon exchange diagrams into account at high transfer momentum are used. Based on calculation of the matrix element one can obtain matrix element for given process. It is shown that the effective cross section which takes one photon exchange into account is obtained. (author)

Current algebra formulation of radiative corrections in gauge theories and the universality of the weak interactions

Energy Technology Data Exchange (ETDEWEB)

Sirlin, A.

1978-07-01

A current algebra formulation of the radiative corrections in gauge theories, with special applications to the analysis of the universality of the weak interactions, is developed in the framework of quantum chromodynamics. For definiteness, we work in the SU(2) x U(1) model with four quark flavors, but the methods are quite general and can be applied to other theories. The explicit cancellation of ultraviolet divergences for arbitrary semileptonic processes is achieved relying solely on the Ward identities and general considerations, both in the W and Higgs sectors. The finite parts of order G/sub F/..cap alpha.. are then evaluated in the case of the superallowed Fermi transitions, including small effects proportional to g/sup -2//sub S/(kappa/sup 2/), which are induced by the strong interactions in the asymptotic domain. We consider here both the simplest version of the Weinberg--Salam model in which the Higgs scalars transform as a single isospinsor, as well as the case of general symmetry breaking. Except for the small effects proportional to g/sup -2//sub S/(kappa/sup 2/), the results are identical to the answers previously found on the basis of heuristic arguments. The phenomenological verification of Cabibbo universality on the basis of these corrections and the superallowed Fermi transitions has been discussed before and found to be in very good agreement with present experimental evidence. The analogous calculation for the transition rate of pion ..beta.. decay is given. Theoretical alternatives to quantum chromdynamics as a framework for the evaluate ion of the radiative corrections are briefly discussed. The appendixes contain a generalization of an important result in the theory of radiative corrections, an analysis of the hadronic contributions to the W and phi propagators, mathematical methods for evaluating the g/sup -2//sub S/(kappa/sup 2/) corrections, and discussions of quark mass renormalization and the absence of operator &apos

Poster - 17: Characterization and correction of radiation induced background in scanning water tanks

Energy Technology Data Exchange (ETDEWEB)

Ali, Elsayed [The Ottawa Hospital Cancer Centre (Canada)

2016-08-15

Purpose: To characterize and correct for radiation-induced background (RIB) observed in the signals from a class of scanning water tanks. Methods: A method was developed to isolate the RIB through detector measurements in the background-free linac console area. Variation of the RIB against a large number of parameters was characterized, and its impact on basic clinical data for photon and electron beams was quantified. Different methods to minimize and/or correct for the RIB were proposed and evaluated. Results: The RIB is due to the presence of the electrometer and connection box in a low background radiation field (by design). The absolute RIB current with a biased detector is up to 2 pA, independent of the detector size, which is 0.6% and 1.5% of the central axis reference signal for a standard and a mini scanning chamber, respectively. The RIB monotonically increases with field size, is three times smaller for detectors that do not require a bias (e.g., diodes), is up to 80% larger for positive (versus negative) polarity, decreases with increasing photon energy, exhibits a single curve versus dose rate at the electrometer location, and is negligible for electron beams. Data after the proposed field-size correction method agree with point measurements from an independent system to within a few tenth of a percent for output factor, head scatter, depth dose at depth, and out-of-field profile dose. Manufacturer recommendations for electrometer placement are insufficient and sometimes incorrect. Conclusions: RIB in scanning water tanks can have a non-negligible effect on dosimetric data.

Comportement des fondations et des ancrages de structures marines sous l'effet de sollicitations cycliques Behavior of Foundations and Anchors for Marine Structures under the Effect of Cyclic Stresses

Directory of Open Access Journals (Sweden)

Le Tirant P.

2006-11-01

Full Text Available L'exploration et l'exploitation des hydrocarbures en haute mer conduisent à la mise en place d'ouvrages fixes ou flottants de dimensions de plus en plus colos sales, par des profondeurs d'eau sans cesse croissantes, atteignant actuellement 200 à 300 mètres en production, un millier de mètres en exploration. Les fondations des ouvrages pétroliers de production comprennent essentiel-lement- les pieux ou groupes de pieux, battus ou forés; - les fondations superficielles à embase poids. Le comportement des fondations ou ancrages de structures sous l'action des sollicitations cycliques est étudié, en fonction de la nature des terrains, à partir - de mesures et d'observations sur des structures réelles; d'expérimentations sur des modèles en semi-grandeur ou de simulations sur modèles réduits. Les exemples donnés situent la diversité des problèmes rencontrés pour l'instal-lation des ouvrages en haute mer et! l'ampleur des travaux nécessaires pour décrire plus correctement les phénomènes d'intéraction sols-structures mannes sous l'effet des chargements cycliques et transitoires et, par suite, mieux optimiser le dimensionnement des fondations et des ancrages. Exploration and production of hydrocarbons in the high seas lead ta the installation of fixed or floating structures having more and more colossal sizes at constantly increasing water depths which now attain 200 ta 300 meters for production and 1000 meters for exploration. The foundations of ail production structures mainly consist of - pilings or groups of pilings, either driven or drilled; superficial gravity foundations the behovior of foundations or anchors for such structures under the effect of cyclic stresses is examined as a function of the nature of formations, on the basis of - measurements and observations on actual structures, experiments with semi-full-sized models or by simulations with scale models. The examples given illustrate the diversity of the problems

Resonance absorption of nuclear gamma radiation; Absorption par resonance des rayons gamma; Rezonansnaya absorbtsiya i rasseyanie yadernogo gamma-izlucheniya; Absorcion por resonancia de las radiaciones gamma en los nucleos

Energy Technology Data Exchange (ETDEWEB)

Hanna, S S; Perlow, G J [Argonne National Laboratory, Argonne, IL (United States)

1962-01-15

Recoilless emission and absorption of nuclear radiation, as demonstrated by Moessbauer, provides a simple means of studying the interaction of nuclei with electromagnetic radiation and, of greater importance, provides an extremely sensitive tool for the investigation of a large number of physical problems. A very favourable situation arises with the Fe{sup 57} nucleus where resonance absorption may be used as a very sensitive detector of the frequency change of electromagnetic radiation. Resonance absorption in Fe57 has been studied in detail. The strength of the absorption, the line shape, and line shift have all been observed as a function of temperature. The polarization of the radiation has been examined by means of experiments with magnetized sources and absorbers. The hyperfine spectrum of the resonance radiation has been analysed with and without polarization. These studies have led to an interpretation of the hyperfine structure in terms of the properties of the nuclear states and the hyperfine interaction in iron. The effect of an external magnetic field on the hyperfine structure has also been investigated. The resonance absorption in Fe{sup 57} has been used to study the connexion between the time development of the decay of a nuclear state and the spectrum of the observed radiation. Detailed observations are made of the time spectrum of filtered resonance radiation for a variety of conditions. (author) [French] L'emission et l'absorption de rayonnements nucleaires sans recul, phenomenes mis en evidence par Mossbauer, offrent un moyen simple d'etudier l'interaction des noyaux et des rayonnements electromagnetiques et, ce qui est plus important encore, fournissent un instrument extremement sensible pour l'etude d'un grand nombre de problemes de physique. Une situation tres favorable se presente dans le cas du noyau de {sup 57}Fe, ou l'on peut utiliser l'absorption par resonance comme un detecteur tres sensible des changements de frequence des rayonnements

The fortran programme for the calculation of the absorption and double scattering corrections in cross-section measurements with fast neutrons using the monte Carlo method (1963); Programme fortran pour le calcul des corrections d'absorption et de double diffusion dans les mesures de sections efficaces pour les neutrons rapides par la methode de monte-carlo (1963)

Energy Technology Data Exchange (ETDEWEB)

Fernandez, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

A calculation for double scattering and absorption corrections in fast neutron scattering experiments using Monte-Carlo method is given. Application to cylindrical target is presented in FORTRAN symbolic language. (author) [French] Un calcul des corrections de double diffusion et d'absorption dans les experiences de diffusion de neutrons rapides par la methode de Monte-Carlo est presente. L'application au cas d'une cible cylindrique est traitee en langage symbolique FORTRAN. (auteur)

Radiative corrections in supersymmetry and application to relic density calculation beyond leading order

International Nuclear Information System (INIS)

Chalons, G.

2010-07-01

This thesis focuses on the evaluation of supersymmetric radiative corrections for processes involved in the calculation of the relic density of dark matter, in the MSSM (Minimal Supersymmetric Standard Model) and the standard cosmological scenario, as well as the impact of the choice renormalisation scheme in the neutralino/chargino sector based on the measure of three physical masses. This study has been carried out with the help of an automatic program dedicated the the computation of physical observables at one-loop in the MSSM, called SloopS. For the relic density calculation we investigated scenarios where the most studied dark matter candidate, the neutralino, annihilates into gauge boson pair. We covered cases where its mass was of the order of hundreds of GeV to 2 TeV. The full set of electroweak and strong corrections has been taken into account, involved in sub-leading channels with quarks. In the case of very heavy neutralinos, two important effects were outlined: the Sommerfeld enhancement due to massive gauge bosons and maybe even more important some corrections of Sudakov type. (authors)

Efficacité des néonicotinoïdes et des pyréthrinoïdes utilisés contre le ...

African Journals Online (AJOL)

Efficacité des néonicotinoïdes et des pyréthrinoïdes utilisés contre le foreur des tiges du cacaoyer ( Eulophonotus myrmeleon Felder : Lepidoptera, Cossidae). Implications dans la stratégie de protection de la cacaoculture en Côte d'Ivoire.

OGM Diffusion des OGM et impact pour les agriculteurs : quels sont les liens ?

Directory of Open Access Journals (Sweden)

Lemarie Stéphane

2001-05-01

Full Text Available Les OGM actuellement sur le marché présentent des innovations sur des fonctions de protection des plantes. Selon les problèmes de protection des plantes, les gains des agriculteurs liés à l’adoption des OGM sont très variables. Cette hétérogénéité pose d’importants problèmes méthodologiques pour pouvoir estimer correctement la distribution des gains pour l’ensemble des agriculteurs. Une synthèse de plusieurs études américaines est réalisée ici et met bien en évidence la diversité des méthodes utilisées, chacune d’elles présentant ses avantages et ses limites. Globalement, si la diffusion des OGM est un fait indéniable, les études ne permettent pas de tirer des conclusions aussi nettes quant à l’impact des OGM pour tous les agriculteurs qui adoptent ces produits, et cela en particulier pour le soja. Cette absence de conclusion s’explique en grande partie par la difficulté à mesurer certains facteurs qui influencent le comportement d’adoption, comme par exemple la simplification de la conduite des cultures. En contrepartie, il faut noter que les études présentées ici ne prennent pas en compte un certain nombre d’effets indirects qui peuvent faire diminuer les gains des agriculteurs.

Monte Carlo study of MOSFET dosimeter dose correction factors considering energy spectrum of radiation field in a steam generator channel head

Energy Technology Data Exchange (ETDEWEB)

Cho, Sung Koo; Choi, Sang Hyoun; Kim, Chan Hyeong [Hanyang Univ., Seoul (Korea, Republic of)

2006-12-15

In Korea, a real-time effective dose measurement system is in development. The system uses 32 high-sensitivity MOSFET dosimeters to measure radiation doses at various organ locations in an anthropomorphic physical phantom. The MOSFET dosimeters are, however, mainly made of silicon and shows some degree of energy and angular dependence especially for low energy photons. This study determines the correction factors to correct for these dependences of the MOSFET dosimeters for accurate measurement of radiation doses at organ locations in the phantom. For this, first, the dose correction factors of MOSFET dosimeters were determined for the energy spectrum in the steam generator channel of the Kori Nuclear Power Plant Unit no.1 by Monte Carlo simulations. Then, the results were compared with the dose correction factors from 0.662 MeV and 1.25 MeV mono-energetic photons. The difference of the dose correction factors were found very negligible ({<=}1.5%), which in general shows that the dose corrections factors determined from 0.662 MeV and 1.25 MeV can be in a steam general channel head of a nuclear power plant. The measured effective dose was generally found to decrease by {approx}7% when we apply the dose correction factors.

Measurement and analysis of high energy radiation through activation detectors. Application in dosimetry; Sur la mesure et l'analyse des rayonnements de haute energie par detecteurs a activation. Application a la dosimetrie

Energy Technology Data Exchange (ETDEWEB)

Sklavenitis, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-10-15

This work is concerned with the possibility of measurement and analysis of radiation fluences within objects of small volume submitted to a high energy proton beam. The first part, consecrated to the establishment of a method of analysis, comprises a detailed study of the radiation nature and energy spectra as well as of the various dosimetry methods. In order to select a group of detectors, high energy nuclear reactions were systematically studied and for some of them cross sections were measured or calculated: for example the cross section of the reaction {sup 11}B (p,n) {sup 11}C between 150 and 3000 MeV and of the reaction {sup 34}S (p,2pn) {sup 32}P between 50 and 3000 MeV. The second part is relative to the application of the fore-mentioned analysis to radiation within a tissue equivalent phantom irradiated by 3 GeV protons. This analysis is sufficiently detailed to allow the reconstitution of the absorbed doses, the dose equivalent and, contingent on a better knowledge of the dose due to heavy particles, the quality factors. It allowed also to follow the evolution of the various dosimetric data as a function of the depth inside the phantom and to verify calculations already done by other researchers. The comparison of the measured doses and the corresponding detector activities revealed the possibility that some detectors could give directly the absorbed dose, or even the dose equivalent, by a simple activity measurement. (author) [French] Le travail porte sur la possibilite de mesure et d'analyse, a l'aide de detecteurs a activation, des fluences de rayonnements a l'interieur d'un objet de petit volume soumis a un faisceau de protons de tres haute energie. La premiere partie, consacree a la mise au point de la methode d'analyse des fluences, comporte une etude detaillee de la nature des rayonnements et de leurs spectres energetiques ainsi que des differentes methodes de dosimetrie. Pour arriver au choix d'un groupe de detecteurs, une etude systematique des

Santé des adolescents et des jeunes au Burkina Faso : état des ...

African Journals Online (AJOL)

Il s'est agi d'une étude évaluative ayant utilisé une revue documentaire associée à une interview des acteurs clés et un atelier de validation et d'identification des interventions pertinentes pour un plan stratégique national. La situation de la santé des adolescents et des jeunes est caractérisée par des grossesses précoces ...

Modelling solar radiation interception in row plantation. 3. Application to a traditional vineyard; Modélisation de l’interception des rayonnements solaires dans une culture en rangs. 3. Application à une vigne traditionnelle

Energy Technology Data Exchange (ETDEWEB)

Sinoquet, H. [Institut National de la Recherche Agronomique, Pointe a Pitre (France); Valancogne, C.; Lescure, A.; Bonhomme, R.

1992-07-01

A previously described model of solar radiation interception was applied to a spatially discontinuous canopy: that of a traditional vineyard in which the classical terms of the radiative balance and the spatial distribution of the radiation transmitted to the soil were measured. Comparison of measured and simulated data gave satisfactory agreement for reflected radiation (fig 4), but major discrepancies appeared for mean transmitted radiation (fig 5). The use of small stationary sensors for measuring the transmitted radiation explains the latter observation, since most of the time they measured radiation received on the ground in the sunflecks or in the shaded area rather than mean radiation. This was verified by comparing the measured and simulated spatial distribution of transmitted radiation (figs 7, 8). Finally, the influence of the woody parts which were not taken into consideration in the model was clearly identified : it significantly reduced the transmission of incident radiation (fig 9), and to a greater degrees the closer the sensor was to the vegetation row. (author) [French] Un modèle d’interception du rayonnement solaire décrit précédemment est appliqué à un couvert spatialement discontinu : une vigne traditionnelle sur laquelle ont été mesurés les termes classiques du bilan radiatif et la distribution spatiale du rayonnement transmis au sol. La comparaison des mesures au modèle révèle un ajustement satisfaisant pour le rayonnement réfléchi (fig 4), mais assez médiocre pour le rayonnement transmis moyen (fig 5). Ceci est expliqué par l’utilisation de capteurs ponctuels qui, en raison de leur taille, mesurent plus souvent le rayonnement reçu au sol dans les taches de soleil ou les zones d’ombre qu’un rayonnement moyen. Ceci est vérifié en comparant les distributions mesurées et calculées du rayonnement transmis au sol (figs 7 et 8). Enfin, l’influence des parties ligneuses, non prise en compte dans le modèle, est

La fabrique des sciences des institutions aux pratiques

CERN Document Server

Benninghoff, Martin; Crettaz von Roten, Fabienne; Merz, Martina

2006-01-01

Aujourd'hui, les façons de produire, d'organiser, d'évaluer et d'utiliser les savoirs sont en profond débat. De plus en plus, l'Etat, la société civile et l'économie tentent d'influencer les activités des universités et des laboratoires de recherche. Ces développements mettent à l'épreuve tout à la fois les fondements des systèmes d'enseignement supérieur et de recherche, l'autonomie des institutions scientifiques, la définition des frontières des savoirs et l'acceptation des sciences. Dans des contextes suisses et européens, cet ouvrage s'intéresse aux manières dont les sciences et les technologies sont fabriquées, en analysant leurs institutions et les pratiques. A partir d'une approche relationnelle, les sciences et les technologies sont conçues comme des phénomènes profondément sociaux, culturels et politiques. Une telle démarche déstabilise les visions parfois idéalisées et stéréotypées de la construction des savoirs. Des études de cas détaillées décrivent des phénomè...

Fast shading correction for cone beam CT in radiation therapy via sparse sampling on planning CT.

Science.gov (United States)

Shi, Linxi; Tsui, Tiffany; Wei, Jikun; Zhu, Lei

2017-05-01

The image quality of cone beam computed tomography (CBCT) is limited by severe shading artifacts, hindering its quantitative applications in radiation therapy. In this work, we propose an image-domain shading correction method using planning CT (pCT) as prior information which is highly adaptive to clinical environment. We propose to perform shading correction via sparse sampling on pCT. The method starts with a coarse mapping between the first-pass CBCT images obtained from the Varian TrueBeam system and the pCT. The scatter correction method embedded in the Varian commercial software removes some image errors but the CBCT images still contain severe shading artifacts. The difference images between the mapped pCT and the CBCT are considered as shading errors, but only sparse shading samples are selected for correction using empirical constraints to avoid carrying over false information from pCT. A Fourier-Transform-based technique, referred to as local filtration, is proposed to efficiently process the sparse data for effective shading correction. The performance of the proposed method is evaluated on one anthropomorphic pelvis phantom and 17 patients, who were scheduled for radiation therapy. (The codes of the proposed method and sample data can be downloaded from https://sites.google.com/view/linxicbct) RESULTS: The proposed shading correction substantially improves the CBCT image quality on both the phantom and the patients to a level close to that of the pCT images. On the phantom, the spatial nonuniformity (SNU) difference between CBCT and pCT is reduced from 74 to 1 HU. The root of mean square difference of SNU between CBCT and pCT is reduced from 83 to 10 HU on the pelvis patients, and from 101 to 12 HU on the thorax patients. The robustness of the proposed shading correction is fully investigated with simulated registration errors between CBCT and pCT on the phantom and mis-registration on patients. The sparse sampling scheme of our method successfully

Evaluation of Setup Error Correction for Patients Using On Board Imager in Image Guided Radiation Therapy

International Nuclear Information System (INIS)

Kang, Soo Man

2008-01-01

To reduce side effects in image guided radiation therapy (IGRT) and to improve the quality of life of patients, also to meet accurate SETUP condition for patients, the various SETUP correction conditions were compared and evaluated by using on board imager (OBI) during the SETUP. Each 30 cases of the head, the neck, the chest, the belly, and the pelvis in 150 cases of IGRT patients was corrected after confirmation by using OBI at every 2-3 day. Also, the difference of the SETUP through the skin-marker and the anatomic SETUP through the OBI was evaluated. General SETUP errors (Transverse, Coronal, Sagittal) through the OBI at original SETUP position were Head and Neck: 1.3 mm, Brain: 2 mm, Chest: 3 mm, Abdoman: 3.7 mm, Pelvis: 4 mm. The patients with more that 3 mm in the error range were observed in the correction devices and the patient motions by confirming in treatment room. Moreover, in the case of female patients, the result came from the position of hairs during the Head and Neck, Brain tumor. Therefore, after another SETUP in each cases of over 3 mm in the error range, the treatment was carried out. Mean error values of each parts estimated after the correction were 1 mm for the head, 1.2 mm for the neck, 2.5 mm for the chest, 2.5 mm for the belly, and 2.6 mm for the pelvis. The result showed the correction of SETUP for each treatment through OBI is extremely difficult because of the importance of SETUP in radiation treatment. However, by establishing the average standard of the patients from this research result, the better patient satisfaction and treatment results could be obtained.

Evaluation of Setup Error Correction for Patients Using On Board Imager in Image Guided Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Kang, Soo Man [Dept. of Radiation Oncology, Kosin University Gospel Hospital, Busan (Korea, Republic of)

2008-09-15

To reduce side effects in image guided radiation therapy (IGRT) and to improve the quality of life of patients, also to meet accurate SETUP condition for patients, the various SETUP correction conditions were compared and evaluated by using on board imager (OBI) during the SETUP. Each 30 cases of the head, the neck, the chest, the belly, and the pelvis in 150 cases of IGRT patients was corrected after confirmation by using OBI at every 2-3 day. Also, the difference of the SETUP through the skin-marker and the anatomic SETUP through the OBI was evaluated. General SETUP errors (Transverse, Coronal, Sagittal) through the OBI at original SETUP position were Head and Neck: 1.3 mm, Brain: 2 mm, Chest: 3 mm, Abdoman: 3.7 mm, Pelvis: 4 mm. The patients with more that 3 mm in the error range were observed in the correction devices and the patient motions by confirming in treatment room. Moreover, in the case of female patients, the result came from the position of hairs during the Head and Neck, Brain tumor. Therefore, after another SETUP in each cases of over 3 mm in the error range, the treatment was carried out. Mean error values of each parts estimated after the correction were 1 mm for the head, 1.2 mm for the neck, 2.5 mm for the chest, 2.5 mm for the belly, and 2.6 mm for the pelvis. The result showed the correction of SETUP for each treatment through OBI is extremely difficult because of the importance of SETUP in radiation treatment. However, by establishing the average standard of the patients from this research result, the better patient satisfaction and treatment results could be obtained.

Political correctness: mental disorder, childish fad or advance of human civilization?

OpenAIRE

Geser, Hans

2008-01-01

Der vorliegende Beitrag befasst sich mit dem Begriff der "Political Correctness"(PC). Nach einem kurzen Überblick über den Entstehungshintergrund und die unterschiedliche Auslegungen in verschiedenen Ländern geht der Autor auf die moralische Dimension ein. Der nächste Abschnitt befasst sich mit der normativen Kraft von Sprache und dem Rückfall in binäre Gut-Schlecht-Kategorien. Im Anschluss daran wird die kulturelle Dimension des Begriffs und die Gefahr des paternalistischen kulturellen Relat...

Radiative Corrections to e+e-→ Zh at Future Higgs Factory in the Minimal Dilaton Model

International Nuclear Information System (INIS)

Heng Zhao-Xia; Li Dong-Wei; Zhou Hai-Jing

2015-01-01

The minimal dilaton model (MDM) extends the Standard Model by one singlet scalar called dilaton and one top quark partner called t'. In this work we investigate the t'-induced radiative correction to the Higgs-strahlung production process e + e − → Zh at future Higgs factory. We first present the analytical calculations in detail and show how to handle the ultraviolet divergence. Then we calculate the correction numerically by considering the constraints from precision electroweak data. We find that, for sinθ L = 0.2 and m t' = 1200 GeV, the correction is 0.26% and 2.1% for √s e + e - - 240 GeV, 1 TeV respectively, and a larger value can be achieved as sin θ L increases. (physics of elementary particles and fields)

Measurement and analysis of high energy radiation through activation detectors. Application in dosimetry; Sur la mesure et l'analyse des rayonnements de haute energie par detecteurs a activation. Application a la dosimetrie

Energy Technology Data Exchange (ETDEWEB)

Sklavenitis, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-10-15

This work is concerned with the possibility of measurement and analysis of radiation fluences within objects of small volume submitted to a high energy proton beam. The first part, consecrated to the establishment of a method of analysis, comprises a detailed study of the radiation nature and energy spectra as well as of the various dosimetry methods. In order to select a group of detectors, high energy nuclear reactions were systematically studied and for some of them cross sections were measured or calculated: for example the cross section of the reaction {sup 11}B (p,n) {sup 11}C between 150 and 3000 MeV and of the reaction {sup 34}S (p,2pn) {sup 32}P between 50 and 3000 MeV. The second part is relative to the application of the fore-mentioned analysis to radiation within a tissue equivalent phantom irradiated by 3 GeV protons. This analysis is sufficiently detailed to allow the reconstitution of the absorbed doses, the dose equivalent and, contingent on a better knowledge of the dose due to heavy particles, the quality factors. It allowed also to follow the evolution of the various dosimetric data as a function of the depth inside the phantom and to verify calculations already done by other researchers. The comparison of the measured doses and the corresponding detector activities revealed the possibility that some detectors could give directly the absorbed dose, or even the dose equivalent, by a simple activity measurement. (author) [French] Le travail porte sur la possibilite de mesure et d'analyse, a l'aide de detecteurs a activation, des fluences de rayonnements a l'interieur d'un objet de petit volume soumis a un faisceau de protons de tres haute energie. La premiere partie, consacree a la mise au point de la methode d'analyse des fluences, comporte une etude detaillee de la nature des rayonnements et de leurs spectres energetiques ainsi que des differentes methodes de dosimetrie. Pour arriver au choix d'un groupe de

Effects of radiation; Effets des radiations

Energy Technology Data Exchange (ETDEWEB)

Masse, R [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

2006-07-01

The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

Effects of radiation; Effets des radiations

Energy Technology Data Exchange (ETDEWEB)

Masse, R. [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

2006-07-01

The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

Tombes et cimetières éthiopiens : des rois, des saints, des anonymes1

OpenAIRE

Derat, Marie-Laure

2009-01-01

L’histoire des tombes et cimetières éthiopiens, dans la longue durée, en est encore à ses balbutiements. Si les tombes des saints et des rois nous sont un peu mieux connus grâce à des textes témoignant à la fois des enjeux entourant les sépultures de ces personnages hors du commun et des soins apportés à leur inhumation, en revanche, les cimetières ordinaires échappent encore largement à l’enquête, en grande partie parce que le commun des mortels est inhumé dans l’anonymat et dans un grand dé...

Évaluation des pratiques agricoles des légumes feuilles : le cas des ...

African Journals Online (AJOL)

Face à ce constat, le défi de la recherche serait la détermination du niveau actuel de contamination des légumes feuilles et des eaux du barrage et celui de l'État serait l'initiation de programmes de sensibilisation des producteurs par rapport à une gestion plus rigoureuse des pesticides. Mots-clés : pratiques paysannes, ...

Mini-Proceedings, 18th Meeting of the Working Group on Radiative Corrections and MC Generators for Low Energies

CERN Document Server

Masjuan, P; Venanzoni, G

2016-01-01

The mini-proceedings of the 18$^{\\mathrm{th}}$ Meeting of the "Working Group on Radiative Corrections and MonteCarlo Generators for Low Energies" held in Frascati, 19$^{\\mathrm{th}}$ - 20$^{\\mathrm{st}}$ May, are presented. These meetings, started in 2006, have as aim to bring together experimentalists and theoreticians working in the fields of meson transition form factors, hadronic contributions to the anomalous magnetic moment of the leptons, and the effective fine structure constant. The development of MonteCarlo generators and Radiative Corrections for precision $e^+e^-$ and $\\tau$-lepton physics are also covered, with emphasis on meson production. At this workshop, a documentary entitled {\\it Bruno Touschek with AdA in Orsay} commemorating the first observation of electron-positron collisions in a laboratory was also presented. With this edition, the working group reaches 10 years of continuous activities.

Displacements and intensities of the components of hydrogenic lines of the helium atom in the presence of exterior uniform electrical and magnetic fields; Deplacements et intensites des composantes des raies hydrogenoides de l'atome d'helium en presence de champs exterieurs electrique et magnetique uniformes

Energy Technology Data Exchange (ETDEWEB)

Deutsch, C; Herman, L; Nguyen, H [Laboratoire de Recherches Physiques, 75 - Paris (France); Drawin, H W [Commissariat a l' Energie Atomique, Association Euratom-CEA, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1967-07-01

The Waller-Foster method for hydrogenic lines of neutral helium is extended in order to take into account an external magnetic field (vector K) having an arbitrary angle with an external constant electric field (vector F). The diagonal correction has been evaluated numerically taking into account recent experimental data. A Fortran IV program written for the CDC 3600 computer allows to calculate the displacements and the intensities for any hydrogenic transition. Special attention is given to the {l_brace}2-4{r_brace} transitions in neutral helium. (authors) [French] La methode de perturbation de Waller et Foster est generalisee afin de tenir compte d'un champ magnetique exterieur (vecteurK) faisant un angle quelconque avec un champ electrique exterieur (vecteurF). La correction diagonale des matrices de perturbation est evaluee numeriquement a l'aide des donnees atomiques les plus recentes. Un programme ecrit pour l'ordinateur CDC 3600 permet le calcul des deplacements et des intensites pour des transitions hydrogenoides quelconques. Les transitions [2-4]d'helium neutre ont ete etudiees plus particulierement. (auteurs)

La convergence des rôles respectifs des relationnistes et des journalistes influence-t-elle la perception qu'ils ont les uns des autres?

DEFF Research Database (Denmark)

Valentini, Chiara

2017-01-01

la convergence des rôles respectifs des praticiens des relations publiques et des journalistes a un effet favorable sur la perception qu’ils ont les uns des autres. L’effet est plus marqué chez les praticiens des relations publiques, car leur vision de la profession en journalisme correspond à celle...

Mécanique des sols et des roches

CERN Document Server

Vullier, Laurent; Zhao, Jian

2016-01-01

La mécanique des sols et la mécanique des roches sont des disciplines généralement traitées séparément dans la littérature. Pour la première fois, un traité réunit ces deux spécialités, en intégrant également les connaissances en lien avec les écoulements souterrains et les transferts thermiques. A la fois théorique et pratique, cet ouvrage propose tout d'abord une description détaillée de la nature et de la composition des sols et des roches, puis s'attache à la modélisation de problèmes aux conditions limites et présente les essais permettant de caractériser les sols et les roches, tant d'un point de vue mécanique qu'hydraulique et thermique. La problématique des sols non saturés et des écoulements multiphasiques est également abordée. Une attention particulière est portée aux lois de comportement mécanique et à la détermination de leurs paramètres par des essais in situ et en laboratoire, et l'ouvrage offre également une présentation détaillée des systèmes de classi...

The Use of Ionizing Radiation in the Vulcanization of Silicon Rubber; Utilisation des radiations ionisantes pour la vulcanisation du caoutchouc au silicone; Ispol'zovanie ioniziruyushchikh izluchenij dlya vulkanizatsii silikonovogo kauchuka; Empleo de las radiaciones ionizantes en la vulcanizacion del caucho de siliconas

Energy Technology Data Exchange (ETDEWEB)

Kuzminsky, A S; Nikitina, T S; Oksentevich, L A [Rubber Research Institute, Moscow, Union of Soviet Socialist Republics (Russian Federation)

1960-07-15

Main purpose of the work - a detailed study of the properties of materials obtained by irradiating mixtures of polydimethylsiloxan e rubber and various fillers (special silicic acid, titanium dioxide, flue dust, chimney soot and lamp black). The irradiation was done with a powerful X-ray unit and a Co{sup 60} gamma-ray source of 20,000 gr. radium equivalent. The relative speed of formation of the space lattice of the vulcanized material was evaluated (by the size of the equilibrium constant and the maximum degree of swelling in benzene). Changes in tensile strength and specific elongation during the irradiation process were studied. The optimum vulcanization regime was chosen and the basic physico-mechanical characteristics of the vulcanized materials were defined. Changes in the properties of the irradiated vulcanized material during hot aging at temperatures of 150{sup o}, 200{sup o} and 250{sup o} were studied. Irradiation in vulcanization removes the necessity for carrying out the process at high temperatures and for keeping the product under controlled temperature conditions for long periods after vulcanization. This new method of vulcanizing allows the use of carbon black as a filler. The use of ionizing radiation makes it possible to simplify the technique of vulcanizing silicon rubber and to improve the properties of the vulcanized material. (author) [French] L'etude porte avant tout sur les proprietes des matieres qu'on obtient apres avoir expose a des radiations du caoutchouc au polydimethyl-siloxane melange a des produits d'addition differents (acide silicique special, bioxyde de titane, noir de fumee en poudre impalpable obtenu au four et a la lampe). L'exposition aux radiations s'effectuait dans une installation puissante de rayons X et avec une source de rayonnement gamma en {sup 60}Co avec une activite de 20 000 g. eq. ra. Les auteurs ont evalue la vitesse relative de formation du reseau spatial des vulcanisants (selon la grandeur du module d

A correction to the width of heavy Higgs bosons: An addendum to radiative decay of heavy Higgs bosons

International Nuclear Information System (INIS)

Dicus, D.A.; Willenbrock, S.D.; Imbo, T.D.; Keung, W.Y.; Rizzo, T.G.

1986-04-01

We determine the width for radiative decay of heavy Higgs bosons H → W + W - γ for hard photons as a function of the Higgs boson mass and the photon-energy cutoff, and correct the result of a previous calculation

Évaluation des pratiques agricoles des légumes feuilles : le cas des ...

African Journals Online (AJOL)

SARAH

30 sept. 2017 ... ... de Biochimie et Immunologie Appliquée, Centre de Recherche en Sciences Biologiques, Alimentaires et .... l'intoxication des agriculteurs et des consommateurs, ... source d'alimentation en eau et au pouvoir d'achat des.

Embedded Detection and Correction of SEU Bursts in SRAM Memories Used as Radiation Detectors

CERN Document Server

Secondo, R.; Danzeca, S.; Losito, R.; Peronnard, P.; Masi, A.; Brugger, M.; Dusseau, L.

2016-01-01

SRAM memories are widely used as particle fluence detectors in high radiation environments, such as in the Radiation Monitoring System (RadMon) currently in operation in the CERN accelerator complex. Multiple Cell Upsets (MCUs), arising from micro-latchup events, are characterized by a large number of SEUs, ultimately affecting the measurement of particle fluxes and resulting in corrupted data and accuracy losses. A study of the generation of this type of SEU bursts was performed on an 8 Mbit 90-nm SRAM memory. Experimental tests were carried out with a focused beam of protons on target as well as in a mixed field environment dominated by high energy hadrons. A solution approach using an on-line detection and correction algorithm embedded on an FPGA was investigated and evaluated for use on a RadMon device.

A la poursuite des ondes gravitationnelles dernières nouvelles de l'Univers

CERN Document Server

Binétruy, Pierre

2016-01-01

Nous sommes habitués à observer la lumière des étoiles pour comprendre l’Univers. Ce n’est pourtant pas la radiation la plus présente dans l’Univers mais c’est celle que nous avons d’abord identifiée car nos yeux sont des « détecteurs de lumière ». Or l’Univers est mu par la gravité, non par la lumière. C’est donc la radiation associée, appelée onde gravitationnelle, qui est de première importance pour comprendre le fonctionnement de l’Univers. La détection des ondes gravitationnelles annoncée le 11 février 2016, par le détecteur américain Ligo, a fait l'effet d'une bombe dans les médias. Ce livre, rédigé par un acteur important de cette physique de pointe, nous décrit cet étrange univers gravitationnel qui s'ouvre à nous.

Some Results of the Research Work on the Biological Effect of Neutrons and Protons; Quelques Resultats des Etudes sur les Effets Biologiques des Neutrons et des Protons; Nekotorye itogi izucheniya biologicheskogo dejstviya nejtronov i protonov; Algunos Resultados del Estudio de los Efectos Biologicos de los Neutrones y Protones

Energy Technology Data Exchange (ETDEWEB)

Moskalev, Ju. I. [Institut Biofiziki AMN SSSR, SSSR (Russian Federation)

1964-03-15

The author correlates and analyses the experimental data obtained over the past two or three years regarding the biological effects of neutrons and high-energy protons, and shows that it is a matter of prime concern for present-day radiobiology to investigate the relative biological effectiveness of the various types of radiation under various irradiation conditions and the reasons for the qualitative differences in their effect on the animal organism. Attention is drawn to the need for more research into the combined effect of various types of radiation and other agents. Specific examples are cited to demonstrate the main progress achieved in studying the prophylaxis of radiation injury induced by neutrons or high-energy protons and to show the contribution such research can make towards understanding the specific way in which various types of radiation act. (author) [French] L'auteur generalise les resultats des recherches experimentales qui ont ete faites au cours des deux ou trois dernieres annees sur les effets biologiques des neutrons et protons de haute energie. Il montre qu'une des taches importantes de la radiobiologie moderne est d'etudier a la fois l'efficacite biologique relative des divers types de rayonnements dans des conditions d'irradiation differentes et les differences qualitatives que presente leur action sur l'organisme vivant. Le memoire souligne qu'il est indispensable de developper les recherches sur l'effet combine des divers facteurs: rayonnements et autres. En partant d'exemples concrets, l'auteur expose les principaux resultats des recherches-sur la prophylaxie des radiolesions provoquees par les neutrons et les protons de haute energie; il montre egalement a quel point ces travaux sont necessaires pour mieux comprendre le caractere specifique de l'e ffet des divers types de rayonnements. (author) [Spanish] En esta memoria se generalizan los resultados de los estudios experimentales efectuados en los ultimos dos o tres anos en materia de

Modelisation des effets physico-techniques pour la conception des ...

African Journals Online (AJOL)

automatisation dans les installations industrielles a besoin d'une régulation automatique des commandes des processus technologiques pour lesquelles certaines contraintes sont à relever compte tenu des exigences des innovations scientifiques de ...

Study of the dispersion phenomena connected with the absorption by recoilless nuclear resonance fluorescence; Etude des phenomenes de dispersion lies a l'absorption resonnante sans recul des noyaux atomiques

Energy Technology Data Exchange (ETDEWEB)

Imbert, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-12-01

In nuclear resonance fluorescence as in the optical field abnormal dispersion curves are related to the absorption lines. It is possible, by using quadrupolar or magnetic splitting of the line in the case of recoilless resonance fluorescence (Moessbauer effect) to obtain differential dispersion effects between the two orthogonal linear or the two inverse circular components of the incident gamma radiation. These effects induce bi-refraction phenomena or Faraday rotation on the gamma beam, which have been studied on Fe-57 enriched absorbers. (author) [French] Comme dans le domaine optique, aux raies d'absorption de fluorescence resonnante des noyaux atomiques sont associees des courbes de dispersion anormale. Les decompositions des raies d'absorption de fluorescence resonnante sans recul (raies Moessbauer) par couplage quadrupolaire ou effet Zeeman permettent d'obtenir des effets dispersifs differentiels entre composantes lineaires orthogonales ou circulaires inverses du rayonnement gamma incident. Ces effets se traduisent par des phenomenes de birefringence ou de rotation Faraday, qui ont pu etre etudies sur des milieux enrichis en fer-57. (auteur)

Vecteurs Singuliers des Theories des Champs Conformes Minimales

Science.gov (United States)

Benoit, Louis

En 1984 Belavin, Polyakov et Zamolodchikov revolutionnent la theorie des champs en explicitant une nouvelle gamme de theories, les theories quantiques des champs bidimensionnelles invariantes sous les transformations conformes. L'algebre des transformations conformes de l'espace-temps presente une caracteristique remarquable: en deux dimensions elle possede un nombre infini de generateurs. Cette propriete impose de telles conditions aux fonctions de correlations qu'il est possible de les evaluer sans aucune approximation. Les champs des theories conformes appartiennent a des representations de plus haut poids de l'algebre de Virasoro, une extension centrale de l'algebre conforme du plan. Ces representations sont etiquetees par h, le poids conforme de leur vecteur de plus haut poids, et par la charge centrale c, le facteur de l'extension centrale, commune a toutes les representations d'une meme theorie. Les theories conformes minimales sont constituees d'un nombre fini de representations. Parmi celles-ci se trouvent des theories unitaires dont les representation forment la serie discrete de l'algebre de Virasoro; leur poids h a la forme h_{p,q}(m)=[ (p(m+1) -qm)^2-1] (4m(m+1)), ou p,q et m sont des entiers positifs et p+q= 2. Ces representations possedent un sous-espace invariant engendre par deux sous-representations avec h_1=h_{p,q} + pq et h_2=h_{p,q} + (m-p)(m+1-q) dont chacun des vecteurs de plus haut poids portent le nom de vecteur singulier et sont notes respectivement |Psi _{p,q}> et |Psi_{m-p,m+1-q}>. . Les theories super-conformes sont une version super-symetrique des theories conformes. Leurs champs appartiennent a des representation de plus haut poids de l'algebre de Neveu-Schwarz, une des deux extensions super -symetriques de l'algebre de Virasoro. Les theories super -conformes minimales possedent la meme structure que les theories conformes minimales. Les representations sont elements de la serie h_{p,q}= [ (p(m+2)-qm)^2-4] /(8m(m+2)) ou p,q et m sont

QED radiative corrections and their impact on H → ττ searches at the LHC

Energy Technology Data Exchange (ETDEWEB)

Krasny, Mieczyslaw Witold [Universite Pierre et Marie Curie-Paris 6, Universite Paris Diderot-Paris 7, CNRS-IN2P3, Laboratoire de Physique Nucleaire et des Hautes Energies, Paris (France); Jadach, Stanislaw [Polish Academy of Sciences, Institute of Nuclear Physics, Krakow (Poland); Placzek, Wieslaw [Jagiellonian University, Marian Smoluchowski Institute of Physics, Krakow (Poland)

2016-04-15

In this paper we show that the excess of the ττ events with respect to the Standard Model background predictions, observed by the ATLAS and CMS collaborations and interpreted as the evidence of the Higgs-boson decay into a pair of τ-leptons, may be accounted for by properly taking into account QED radiative corrections in the modelling of the Z/γ* → ττ background. (orig.)

Contribution to the G⁰ violation of parity experience: calculation and simulation of radiative corrections and the background noise study; Contribution a l'experience G0 de violation de la parite : calcul et simulation des corrections radiatives et etude du bruit de fond

Energy Technology Data Exchange (ETDEWEB)

Guler, Hayg [Univ. of Paris, Orsay (France)

2003-12-17

In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrpounded by a sea of gluons and quark-antiquark pairs. Only the only lightest quarks (u, d and s) contribute significantly to the nucleon properties. In Go we using the property of weak interaction to violate parity symmetry, in order to determine separately the contributions of the three types of quarks to nucleon form factors. The experiment, which takes place at Thomas Jefferson laboratory (USA), aims at measuring parity violation asymmetry in electron-proton scattering. By doing several measurements at different momentum squared of the exchanged photons and for different kinematics (forward angle when the proton is detected and backward angle it will be the electron) will permit to determine separately strange quarks electric and magnetic contributions to nucleon form factors. To extract an asymmetry with small errors, it is necessary to correct all the beam parameters, and to have high enough counting rates in detectors. A special electronics was developed to treat information coming from 16 scintillator pairs for each of the 8 sectors of the Go spectrometer. A complete calculation of radiative corrections has been clone and Monte Carlo simulations with the GEANT program has permitted to determine the shape of the experimental spectra including inelastic background. This work will allow to do a comparison between experimental data and theoretical calculations based on the Standard Model.

Contribution to the G{sup 0} experiment about parity violation: calculation and simulation of radiative corrections, study of the background noise; Contribution a l'experience G{sup 0} de violation de la parite: calcul et simulation des corrections radiatives et etude de bruit de fond

Energy Technology Data Exchange (ETDEWEB)

Guler, H

2003-12-01

In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrounded by a sea of gluons and quark-antiquark pairs. Only the only lightest quarks (u, d and s) contribute significantly to the nucleon properties. In G{sup 0} we use the property of weak interaction to violate parity symmetry, in order to determine separately the contributions of the three types of quarks to nucleon form factors. The experiment, which takes place at Thomas Jefferson laboratory (USA), aims at measuring parity violation asymmetry in electron-proton scattering. By doing several measurements at different momentum squared of the exchanged photons and for different kinematics (forward angle when the proton is detected and backward angle it will be the electron) will permit to determine separately strange quarks electric and magnetic contributions to nucleon form factors. To extract an asymmetry with small errors, it is necessary to correct all the beam parameters, and to have high enough counting rates in detectors. A special electronics was developed to treat information coming from 16 scintillator pairs for each of the 8 sectors of the G{sup 0} spectrometer. A complete calculation of radiative corrections has been done and Monte Carlo simulations with the GEANT program has permitted to determine the shape of the experimental spectra including inelastic background. This work will allow to do a comparison between experimental data and theoretical calculations based on the Standard Model. (author)

Extinction correction and synchrotron radiation

International Nuclear Information System (INIS)

Suortti, P.

1983-01-01

The primary extinction factor ysub(p) is defined as the ratio of the integrated reflection from a coherently diffracting domain to the integrated kinematical reflection from the same domain. When ysub(p) is larger than 0.5 it may be approximated by ysub(p)= exp[-(αdelta) 2 ], where α is about 0.5 and delta the average size of the coherent domain when measured in units of the extinction length Λ, delta = D/Λ. Transfer equations are applied to symmetrical Laue diffraction, and the reflectivity per unit length, sigma(epsilon) is solved from the measured reflecting ratio as a function of the rocking angle epsilon = theta -thetasub(B). Measurements with conventional x-ray sources are made on single crystal slabs of Be and Si using AgKβ, MoKα 1 and CuKα radiation. The primary extinction factor ysub(p)(epsilon) is solved from a point-by-point comparison of two measurements where the extinction length Λ is changed by varying the polarization and/or wavelength of the x-ray beam. The results show that primary and secondary extinction are strongly correlated, and that the customary assumption of independent size and orientation distributions of crystal mosaics is unjustified. The structure factors for Be and Si show close agreement with other recent measurements and calculations. The limitations of the method are discussed in length, particularly the effects of beam divergences and incoherence of the rays in the crystal. It is concluded that under typical experimental conditions the requirements of the theory are met. Practical limitations arising from the use of characteristic wavelengths and unpolarized radiation prohibit the use of the full potential of the method. The properties of a synchrotron radiation source are compared with a conventional x-ray source, and it is demonstrated that the experimental limitations can be removed by the use of synchrotron radiation. A diffraction experiment with synchrotron radiation is outlined, as well as generalization of the

Process-independent radiative-correction formula for single-tag and double-tag measurements of γγ reactions

International Nuclear Information System (INIS)

Ong, S.; Kessler, P.

1988-01-01

A simple and process-independent formula is given for radiative corrections in single-tag and double-tag measurements of γγ reactions. Its conditions of validity are that (i) in the γγ process itself all particles produced are detected and (ii) final-state particles, including the tagged electron(s), are measured with a good resolution in energy and momentum

Utilisation sans risque des eaux usées, des excréta et des eaux ...

International Development Research Centre (IDRC) Digital Library (Canada)

Les responsables de ce projet piloteront l'application et l'adaptation des principes directeurs relatifs à l'utilisation sans risque des eaux usées, des excreta et des eaux grises en agriculture et en aquaculture (Guidelines for the Safe Use of Wastewater, Excreta and Greywater in Agriculture and Aquaculture), que ...

The application of {beta}-ray excitation fluorescence to the measurement of the thickness of deposits and to analysis; Applications de la fluorescence excitee au moyen des rayons {beta} a la mesure des epaisseurs des depots et a l'analyse

Energy Technology Data Exchange (ETDEWEB)

Martinelli, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Seibel, G [Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)

1961-07-01

Principles of the method are first outlined and the instrumentation used is described. The different types of radiation detectors are subject of a detailed study. As a source of {beta}-radiation {sup 90}(Sr + Y) was used as well as {sup 147}Pm. Great care was taken to eliminate back-diffused electrons by deflection by a strong permanent magnet. The method was applied to the measurement of the thickness of deposits of Cr, Zn, Sn, Cd and Cu on iron as well as Zn, Cr, Ag and Au on copper and the results obtained are discussed. An attempt was made, to use {beta}-X-ray fluorescence for the analysis of minerals, iron ore and glass and for routine control of Si-Mn, Si-Ca, Fe-Mn and Fe-W. Finally the method of {beta}-X-ray fluorescence is compared with normal-X-ray fluorescence and possibilities of further development are cited. (author) [French] Les principes de la methode et l'instrumentation utilisee sont presentes. On decrit en particulier les detecteurs de rayonnement utilises. Comme source de rayonnement on utilise {sup 90}(Sr + Y) et {sup 147}Pm. Pour eliminer les electrons retrodiffuses on utilise un aimant permanent place sur le trajet du faisceau. La methode est appliquee a la mesure des epaisseurs des depots metalliques tels que le Cr, Zn, Sn, Cd et Cu sur fer et le Zn, Cr, Ag et Au sur cuivre. D'autre part, la fluorescence {beta}-X etait utilisee pour l'analyse des minerais et des verres et pour le controle des alliages Fe-Mn, Fe-W, Si-Mn, Si-Ca. Enfin, on passe a une comparaison entre la fluorescence {beta}-X et la fluorescence X normale et on discute les possibilites d'un developpement futur. (auteur)

ANALYSE DES PERCEPTIONS LOCALES ET DES FACTEURS ...

African Journals Online (AJOL)

AISA

1Faculté des Sciences Agronomiques (FSA), Université d'Abomey-Calavi (UAC), 01 BP 526 Cotonou Bénin. Email : cgbemavo@yahoo.fr. 2Institut National des Recherches Agricoles du Bénin, Centre de Recherches Agricoles d'Agonkanmey (CRA-A),. Laboratoire des Sciences du Sol, Eau et Environnement (LSSEE).

Les traductions néerlandaises des romans francophones camerounais

African Journals Online (AJOL)

28 mars 2016 ... deuxième s'intitule Der alte Mann und die Medaille. Le paratexte des textes publiés par la collection de Derde Spreker est avant tout didactique et en souligne la valeur documentaire: il importe que le lecteur place correctement le roman dans le contexte sociopolitique d'origine. Ainsi le titre original.

variabilite des productions et des revenus des exploitations

African Journals Online (AJOL)

3Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UMR Innovation,. Montpellier, France. Doubangolo COULIBALY, Email kone_b@yahoo.fr. RESUME. La durabilité des systèmes de production à base de coton dans un contexte de variabilité des prix aux producteurs et de ...

Le statut vitaminique des individus et des populations…

Directory of Open Access Journals (Sweden)

Icart Jean-Claude

2000-05-01

Full Text Available Comme le souligne un récent rapport du Haut comité de santé publique, le statut vitaminique des individus et des populations demeure une question d’actualité. Si les études ne révèlent plus de signes évocateurs de carence, au plus des problèmes de déficiences pour certains groupes à risque, des interrogations, demeurent malgré le contexte d’abondance, concernant la couverture des besoins, laquelle pourrait s’avérer inférieure aux valeurs considérées comme satisfaisantes.

Application des TIC à l'atténuation des effets des catastrophes dans ...

International Development Research Centre (IDRC) Digital Library (Canada)

L'Amérique centrale est souvent aux prises avec des inondations et des ... (SIG) et de traitement des images, afin de cartographier les dangers et de modéliser les ... de l'Institut d'étude du développement international de l'Université McGill.

Beta-Excited Sources of Electromagnetic Radiation; Sources de rayonnements electromagnetiques excites par des particules beta; Vozbuzhdennye beta-chastitsami istochniki ehlektromagnitnogo izlucheniya; Fuentes de radiacion electromagnetica excitadas por particulas beta

Energy Technology Data Exchange (ETDEWEB)

Cameron, J F; Rhodes, J R [Physics Group, Isotope Research Division, (AERE), Wantage Research Laboratory, Wantage, Berks (United Kingdom)

1962-01-15

Beta-excited sources of electromagnetic radiation covering the energy region 1-200 keV and suitable for industrial use are described. H{sup 3}, Pm{sup 147}, Kr{sup 85}, Tl{sup 204} and (Sr+Y){sup 90} were chosen as sources of beta particles by the criteria of long half-life, low price, ready availability and high specific activity. The {beta}-excited sources have been designed on the basis of a compromise between practical source construction and the best theoretical efficiency in a given energy region. In their paper, the authors calculate the number of photons produced per beta particle and consider how the results must be corrected for self-absorption of the X-rays. In the calculations account is taken of both bremsstrahlung and characteristic {alpha}-radiation; optimum characteristic X-ray yield is achieved for targets with an atomic number between 40 and 60. ''Sandwich'' targets of 1-2 beta half-value thicknesses are found to give maximum photon-yields in the desired energy region. Al, Ag and Au are suitable from the manufacturing point of view as source coverings. They were also found to give satisfactory bremsstrahlung and X-ray yields and distribution for various energy regions in the range 1-200 keV when correctly combined with the above-mentioned D-emitters. Some energy spectra are given and absorption curves in Al and Fe are shown for the best source-target combinations. The difference between sources constructed of {beta}-emitters sandwiched between target foils and intimate source-target mixtures was found to be small. Tables are given as a guide to the best source to be used for a particular absorber thickness range. (author) [French] Les auteurs decrivent des sources de rayonnements electromagnetiques excites par des particules beta, couvrant une gamme d'energies allant de 1 a 200 keV et convenant aux usages industriels. Comme sources de particules beta on a choisi le tritium, le {sup 147}Pm, le {sup 85}Kr, le {sup 204}Tl et le {sup 90}(Sr+Y), en

Corrections to primordial nucleosynthesis

International Nuclear Information System (INIS)

Dicus, D.A.; Kolb, E.W.; Gleeson, A.M.; Sudarshan, E.C.G.; Teplitz, V.L.; Turner, M.S.

1982-01-01

The changes in primordial nucleosynthesis resulting from small corrections to rates for weak processes that connect neutrons and protons are discussed. The weak rates are corrected by improved treatment of Coulomb and radiative corrections, and by inclusion of plasma effects. The calculations lead to a systematic decrease in the predicted 4 He abundance of about ΔY = 0.0025. The relative changes in other primoridal abundances are also 1 to 2%

La gestion des résultats des entreprises innovantes

OpenAIRE

Dumas, Guillaume

2014-01-01

Cette thèse s’intéresse à la gestion des résultats dans le cadre des entreprises innovantes. Elle est constituée de trois articles. Dans le premier, il s’agit d’examiner si les résultats des entreprises innovantes sont gérés et si le stade de développement des innovations influence cette gestion des résultats. Il apparaît que les résultats des entreprises innovantes sont gérés à la hausse. Cette gestion ne semble intervenir qu’au cours de l’activité d’innovation (c’est-à-dire lorsque les entr...

Etude des erreurs d'estimation des populations par la méthode des captures successives (DeLURY, 2 captures et des captures-recaptures (PETERSEN

Directory of Open Access Journals (Sweden)

LAURENT M.

1978-01-01

Full Text Available L'estimation des populations naturelles par capture-recapture et par captures successives est souvent entachée d'erreur car, dans de nombreux cas, l'hypothèse fondamentale d'égalité des probabilités de captures pour tous les individus dans le temps et dans l'espace n'est pas respectée. Dans le cas des populations de poissons envisagés ici, les captures ont lieu par la pêche électrique. On a pu chiffrer l'ordre de grandeur des erreurs systématiques faites sur l'estimation des peuplements, en fonction des conditions particulières, biotiques et abiotiques, des différents milieux inventoriés.

La circulation des déchets au sein de l’Union européenne. Etude des rapports entre le régime mis en place par le Titre II du Règlement n°1013/2006 et la circulation des marchandises.

OpenAIRE

Krack, Noémie

2017-01-01

La gestion des déchets n’a pas toujours été une priorité pour nos sociétés, et ce même si les Romains et les Grecs faisaient figure de précurseurs. Les découvertes scientifiques relatives aux épidémies de grandes ampleurs, telle la peste noire, démontrèrent l’importance d’un traitement correct des déchets. En effet, leur abandon et leur accumulation sont responsables de la prolifération de germes et microbes pathogènes. Or il faut savoir qu’à l’époque les cités occidentales étaient malsaines ...

Method for determining correction factors induced by irradiation of ionization chamber cables in large radiation field

International Nuclear Information System (INIS)

Rodrigues, L.L.C.

1988-01-01

A simple method was developed to be suggested to hospital physicists in order to be followed during large radiation field dosimetry, to evaluate the effects of cables, connectors and extension cables irradiation and to determine correction factors for each system or geometry. All quality control tests were performed according to the International Electrotechnical Commission for three clinical dosimeters. Photon and electron irradiation effects for cables, connectors and extention cables were investigated under different experimental conditions by means of measurements of chamber sensitivity to a standard radiation source of 90 Sr. The radiation induced leakage current was also measured for cables, connectors and extension cables irradiated by photons and electrons. All measurements were performed at standard dosimetry conditions. Finally, measurements were performed in large fields. Cable factors and leakage factors were determined by the relation between chamber responses for irradiated and unirradiated cables. (author) [pt

Injectabilite des coulis de ciment dans des milieux fissures

Science.gov (United States)

Mnif, Thameur

Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.

La gouvernance des risques naturels et la problematique des ...

African Journals Online (AJOL)

Depuis quelques années, la gouvernance des risques naturels dus aux inondations remet en cause les processus de mise en oeuvre des politiques urbaines et la qualité de la structure des aménagements dans les grandes villes du Golfe de Guinée. La perception de la gouvernance et l'application des politiques de ...

Atmospheric scattering corrections to solar radiometry

International Nuclear Information System (INIS)

Box, M.A.; Deepak, A.

1979-01-01

Whenever a solar radiometer is used to measure direct solar radiation, some diffuse sky radiation invariably enters the detector's field of view along with the direct beam. Therefore, the atmospheric optical depth obtained by the use of Bouguer's transmission law (also called Beer-Lambert's law), that is valid only for direct radiation, needs to be corrected by taking account of the scattered radiation. In this paper we shall discuss the correction factors needed to account for the diffuse (i.e., singly and multiply scattered) radiation and the algorithms developed for retrieving aerosol size distribution from such measurements. For a radiometer with a small field of view (half-cone angle 0 ) and relatively clear skies (optical depths <0.4), it is shown that the total diffuse contributions represents approximately l% of the total intensity. It is assumed here that the main contributions to the diffuse radiation within the detector's view cone are due to single scattering by molecules and aerosols and multiple scattering by molecules alone, aerosol multiple scattering contributions being treated as negligibly small. The theory and the numerical results discussed in this paper will be helpful not only in making corrections to the measured optical depth data but also in designing improved solar radiometers

Estimation de la survie des alevins de carpe (C. carpio au cours de leur premier mois d'existence

Directory of Open Access Journals (Sweden)

MOREAU J.

1979-10-01

Full Text Available Des observations réalisées sur deux stations piscicoles de Madagascar, dans des étangs ne recevant ni engrais ni nourriture, révèlent qu'au cours de leur premier mois les alevins de carpe (C. carpio subissent des mortalités voi-sines de 50 %. Ces dernières sont encore plus élevées en début et en fin de saison de reproduction. Au début, les fortes mortalités sont dues à la température trop basse et aux disponibilités alimentaires insuffisantes ; en fin de saison de reproduction, la température trop élevée et la mauvaise qualité des œufs sont sans doute en cause. Une fumure adéquate des étangs de grossissement des alevins et une alimentation correcte des géniteurs permettront peut-être de diminuer ces mortalités.

Semi-analytic approach to higher-order corrections in simple muonic bound systems: vacuum polarization, self-energy and radiative-recoil

International Nuclear Information System (INIS)

Jentschura, U.D.; Wundt, B.J.

2011-01-01

The current discrepancy of theory and experiment observed recently in muonic hydrogen necessitates a reinvestigation of all corrections to contribute to the Lamb shift in muonic hydrogen (μH), muonic deuterium (μD), the muonic 3 He ion (denoted here as μ 3 He + ), as well as in the muonic 4 He ion (μ 4 He + ). Here, we choose a semi-analytic approach and evaluate a number of higher-order corrections to vacuum polarization (VP) semi-analytically, while remaining integrals over the spectral density of VP are performed numerically. We obtain semi-analytic results for the second-order correction, and for the relativistic correction to VP. The self-energy correction to VP is calculated, including the perturbations of the Bethe logarithms by vacuum polarization. Sub-leading logarithmic terms in the radiative-recoil correction to the 2S-2P Lamb shift of order α(Zα) 5 μ 3 ln(Zα)/(m μ m N ) where α is the fine structure constant, are also obtained. All calculations are nonperturbative in the mass ratio of orbiting particle and nucleus. (authors)

The application of pulsed concentrated solar radiation with the purpose of immune system correction of rheumatic arthritis patients

International Nuclear Information System (INIS)

Shonazarov, N.P.

1996-01-01

The investigation results of dosed pulsed concentrated solar radiation(PCSR) influence to rheumatic arthritis patients are given. It was obtained that PCSR especially in the complex with balneological physiotherapy factors corrects regulator functions of cell link and decreases the density of humoral link of immune system. (author). 2 refs., 2 tabs

The Role of Free-Radicals in the Radiation Vulcanizing of Elastomers; Role des radicaux libres dans la vulcanisation radiochimique des elastomeres; O roli svobodnykh radikalov v protsesse radiatsionnoj vulkanizatsii ehlastomerov; Papel de los radicales libres en la radiovulcanizacion de los elastomeros

Energy Technology Data Exchange (ETDEWEB)

Kuz' minskij, A. S.; Fedoseeva, T. E.; Chertkova, V. F.

1963-11-15

The ability of certain polymers to form cross-links under the action of ionizing radiation has recently been applied in the industrial vulcanization of rubber products. The formation mechanism of a three-dimensional network under the action of radiation is receiving considerable attention from research workers. So far, however, the initial and intermediate stages of the irradiation reactions, leading to the linking of the molecular chains and connected with the formation and destruction of free-radicals, ion radicals and excited molecules, have not been sufficiently investigated. The study of the structure and properties of such fragments has become possible only with the development and wide-spread use of the electron-paramagnetic resonance (EPR) technique, through which information about the structure and properties of paramagnetic particles can be directly obtained. By investigating the recombination process of free-radicals in linear polymers we can get directly at the mechanism of radiation vulcanization. There has recently been a tendency to use ionizing radiation for the de-vulcanization of sulphur vulcanized rubbers, since the combination of sulphur and carbon cross-links gives maximum Improvement in the physico-mechanical properties of products; hence, in this connection is there the interest in studying the kinetic properties of free-radicals'in polymers with a developed space structure. The recombination processes of the free-radicals produced by gamma irradiation are examined in detail in relation to the structural properties of polymer, i.e. to the orientation and internal mobility of molecular chains. In highly elastic polymers of the rubber type, characterized by high internal mobility of the chains and low intermolecular bond energy, the actual recombinations of free-radicals at temperatures above Tg occur at very high speed. The concentration of radicals in rubber samples, irradiated in liquid nitrogen, diminishes on warming up to +20{sup o}C by 1

EFFET DES TRAITEMENTS THERMIQUES SUR LA REACTION ENTRE DES COUCHES MINCES DE TITANE ET DES SUBSTRATS EN ACIER

Directory of Open Access Journals (Sweden)

D Slimani

2015-06-01

Full Text Available Des couches minces du titane pur ont été déposées avec la méthode de pulvérisation cathodique sur des substrats en acier, type FF80 K-1 contenants ~1% mass. en carbone. La réaction entre les deux parties du système substrat-couche mince est activée avec des traitements thermiques sous vide dans l’intervalle de températures de 400 à900°Cpendant 30 minutes. Les Spectres de diffraction de rayons x confirment l’inter- diffusion des éléments  chimiques du système résultants la formation et la croissance des nouvelles phases en particulier le carbure binaire TiC ayant des caractéristiques thermomécaniques importantes. L’analyse morphologique des échantillons traités  avec le microscope électronique à balayage (MEB montre l’augmentation du flux de diffusion atomique avec la température de recuit, notamment la diffusion du manganèse et du fer vers la surface libre des échantillons aux températures élevées provoquant la dégradation des propriétés mécaniques des revêtements contrairement au premiers stades d’interaction où on a obtenu des bonnes valeurs de la microdureté.

Intégration des véhicules intelligents dans un contexte multimodal

OpenAIRE

Gilliéron, Pierre-Yves; Milot, Alexandre Manuel

2016-01-01

L’automatisation des véhicules (privés ou publics) est aujourd'hui devenue un enjeu majeur pour faire face aux besoins de mobilité de demain. L'automatisation ne cesse de croître et d'apporter davantage de confort aux utilisateurs (régulation de vitesse, correction de trajectoire). "L'assistance à la conduite” rime de plus en plus avec “conduite automatisée”, qui permet entre autres, d’assurer un certain niveau de sécurité tout en fluidifiant le trafic grâce à l’anticipation des phases d’accé...

Liver late effects of ionizing radiation; Effets tardifs des radiations sur le foie

Energy Technology Data Exchange (ETDEWEB)

Mornex, F.; Ramuz, O. [Centre Hospitalier Universitaire Lyon-Sud, 69 - Pierre-Benite (France); Gerard, F. [Laboratoire Marcel-Merieux, 69 - Lyon (France); Van Houtte, P. [Institut Bordet, Brussels (Belgium)

1997-12-01

Until recently, the liver was classified as a radioresistant organ, although it is in fact highly radiosensitive. The realization that the whole liver could be treated safety only with low doses of radiation led to the conclusion that radiation therapy had an extremely limited role in the treatment of intrahepatic malignancies. A resurgence of interest has been observed with the advent of conformal radiotherapy and the introduction of bone marrow transplantation with total body irradiation. The radiation-induced liver disease, often called radiation hepatitis, is a syndrome characterized by the development of anicteric ascites, approximately 2 weeks to 4 months after hepatic irradiation. Immediate tolerance is generally surprisingly good, and the subacute radiation injury is followed by a complete asymptomatic healing, although the late lesions may be associated with signs of chronic radiation hepatitis. Radiation hepatitis must be distinguished from chemo-radiation-induced-hepatitis occurring in patients undergoing bone marrow transplantation and total body irradiation. Both syndromes demonstrate the same pathological lesion: veno-occlusive disease. The main treatment for radiation hepatitis is diuretics, although soma advocate steroids for severe cases. (authors)

A proposal for PET/MRI attenuation correction with μ-values measured using a fixed-position radiation source and MRI segmentation

Energy Technology Data Exchange (ETDEWEB)

Kawaguchi, Hiroshi, E-mail: kwgc@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Hirano, Yoshiyuki, E-mail: yhirano@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yoshida, Eiji, E-mail: rush@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kershaw, Jeff, E-mail: len@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shiraishi, Takahiro, E-mail: tshira@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Suga, Mikio, E-mail: mikio.suga@faculty.chiba-u.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Engineering of Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Ikoma, Yoko, E-mail: ikoma@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Obata, Takayuki, E-mail: t_obata@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ito, Hiroshi, E-mail: hito@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yamaya, Taiga, E-mail: taiga@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2014-01-11

Several MRI-based attenuation correction methods have been reported for PET/MRI; these methods are expected to make efficient use of high-quality anatomical MRIs and reduce the radiation dose for PET/MRI scanning. The accuracy of the attenuation map (μ-map) from an MRI depends on the accuracy of tissue segmentation and the attenuation coefficients to be assigned (μ-values). In this study, we proposed an MRI-based μ-value estimation method with a non-rotational radiation source to construct a suitable μ-map for PET/MRI. The proposed method uses an accurately segmented tissue map, the partial path length of each tissue, and detected intensities of attenuated radiation from a fixed-position (rather than a rotating) radiation source to obtain the μ-map. We estimated the partial path length from a virtual blank scan of fixed-point radiation with the same scanner geometry using the known tissue map from MRI. The μ-values of every tissue were estimated by inverting a linear relationship involving the partial path lengths and measured radioactivity intensity. Validation of the proposed method was performed by calculating a fixed- point data set based upon real a real transmission scan. The root-mean-square error between the μ-values derived from a conventional transmission scan and those obtained with our proposed method were 2.4±1.4%, 17.4±9.1% and 6.6±4.3% for brain, bone and soft tissue other than brain, respectively. Although the error estimates for bone and soft tissue are not insignificant, the method we propose is able to estimate the brain μ-value accurately and it is this factor that most strongly affects the quantitative value of PET images because of the large volumetric ratio of the brain. -- Highlights: • An MRI-derived µ-map for the attenuation correction of PET images is proposed. • Method relies on segmentation of MRI and a fixed-point source transmission scan. • Tissue segmentation reduces the number of unknown µ-values. • Method

A proposal for PET/MRI attenuation correction with μ-values measured using a fixed-position radiation source and MRI segmentation

International Nuclear Information System (INIS)

Kawaguchi, Hiroshi; Hirano, Yoshiyuki; Yoshida, Eiji; Kershaw, Jeff; Shiraishi, Takahiro; Suga, Mikio; Ikoma, Yoko; Obata, Takayuki; Ito, Hiroshi; Yamaya, Taiga

2014-01-01

Several MRI-based attenuation correction methods have been reported for PET/MRI; these methods are expected to make efficient use of high-quality anatomical MRIs and reduce the radiation dose for PET/MRI scanning. The accuracy of the attenuation map (μ-map) from an MRI depends on the accuracy of tissue segmentation and the attenuation coefficients to be assigned (μ-values). In this study, we proposed an MRI-based μ-value estimation method with a non-rotational radiation source to construct a suitable μ-map for PET/MRI. The proposed method uses an accurately segmented tissue map, the partial path length of each tissue, and detected intensities of attenuated radiation from a fixed-position (rather than a rotating) radiation source to obtain the μ-map. We estimated the partial path length from a virtual blank scan of fixed-point radiation with the same scanner geometry using the known tissue map from MRI. The μ-values of every tissue were estimated by inverting a linear relationship involving the partial path lengths and measured radioactivity intensity. Validation of the proposed method was performed by calculating a fixed- point data set based upon real a real transmission scan. The root-mean-square error between the μ-values derived from a conventional transmission scan and those obtained with our proposed method were 2.4±1.4%, 17.4±9.1% and 6.6±4.3% for brain, bone and soft tissue other than brain, respectively. Although the error estimates for bone and soft tissue are not insignificant, the method we propose is able to estimate the brain μ-value accurately and it is this factor that most strongly affects the quantitative value of PET images because of the large volumetric ratio of the brain. -- Highlights: • An MRI-derived µ-map for the attenuation correction of PET images is proposed. • Method relies on segmentation of MRI and a fixed-point source transmission scan. • Tissue segmentation reduces the number of unknown µ-values. • Method

Promouvoir l'entrepreneuriat inclusif des jeunes et des femmes ...

International Development Research Centre (IDRC) Digital Library (Canada)

Le projet vise à analyser la contribution réelle et potentielle de l'entrepreneuriat inclusif au bien-être des jeunes et des femmes en Côte d'Ivoire, au Burkina Faso et au Kenya. Après un état des lieux de la pratique de l'entrepreneuriat inclusif dans chacun des pays ciblés, l'équipe de recherche étudiera son incidence sur ...

Radiative corrections to W+jet production at hadron colliders with a leptonic decay of the W boson

Energy Technology Data Exchange (ETDEWEB)

Kasprzik, Tobias

2009-08-31

The production of W bosons and additional jets at hadron colliders is a topic of great phenomenological interest, because such processes have large cross sections and, owing to the clear decay signature of the W boson, can for instance be used to monitor and calibrate the collider's luminosity, as well as for a precise determination of the W-boson mass and width. Thus, a profound theoretical understanding of this process class is mandatory. In order to improve the accuracy of the theoretical predictions, this thesis is devoted to the calculation of the electroweak radiative corrections to the production of one W boson with one associated jet at the LHC and the Tevatron within the Standard Model. Since these corrections are at first evaluated on the parton level in a perturbative approach, we work in the parton model, where the hadronic cross section is obtained by folding the partonic contributions with the parton distribution functions that contain the non-perturbative information of the proton structure and have to be determined by experiment. We provide results for a stable W boson that is produced on its mass shell as well as for an intermediate (off-shell) W boson decaying into a charged lepton and a neutrino. For a consistent calculation of the next-to-leading order corrections, we have to take into account the virtual one-loop contributions, as well as the real bremsstrahlung corrections caused by radiation of one additional photon. Within both contributions, mass singularities appear that have to be treated with care within the numerical evaluation. In the calculation with a stable W boson in the final state, we use the method of phase-space slicing in order to exclude such singularities from the numerical phase-space integration and calculate them analytically in the problematic phase-space regions. For the off-shell calculation, however, we use the more sophisticated dipole subtraction technique to subtract the infrared-singular structures on the

Radiative corrections to W+jet production at hadron colliders with a leptonic decay of the W boson

International Nuclear Information System (INIS)

Kasprzik, Tobias

2009-01-01

The production of W bosons and additional jets at hadron colliders is a topic of great phenomenological interest, because such processes have large cross sections and, owing to the clear decay signature of the W boson, can for instance be used to monitor and calibrate the collider's luminosity, as well as for a precise determination of the W-boson mass and width. Thus, a profound theoretical understanding of this process class is mandatory. In order to improve the accuracy of the theoretical predictions, this thesis is devoted to the calculation of the electroweak radiative corrections to the production of one W boson with one associated jet at the LHC and the Tevatron within the Standard Model. Since these corrections are at first evaluated on the parton level in a perturbative approach, we work in the parton model, where the hadronic cross section is obtained by folding the partonic contributions with the parton distribution functions that contain the non-perturbative information of the proton structure and have to be determined by experiment. We provide results for a stable W boson that is produced on its mass shell as well as for an intermediate (off-shell) W boson decaying into a charged lepton and a neutrino. For a consistent calculation of the next-to-leading order corrections, we have to take into account the virtual one-loop contributions, as well as the real bremsstrahlung corrections caused by radiation of one additional photon. Within both contributions, mass singularities appear that have to be treated with care within the numerical evaluation. In the calculation with a stable W boson in the final state, we use the method of phase-space slicing in order to exclude such singularities from the numerical phase-space integration and calculate them analytically in the problematic phase-space regions. For the off-shell calculation, however, we use the more sophisticated dipole subtraction technique to subtract the infrared-singular structures on the

Processing of data issued from a {gamma} spectrometer; Traitement des informations issues d'un spectrometre {gamma}

Energy Technology Data Exchange (ETDEWEB)

Boulanger, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1966-03-01

The purpose of the following report is the study of computation method applied to analysis by gamma spectrometry. We first study quantitative analysis by the least-squares method, improved by a gain-shift correction. Then the single full-energy peaks and the resolution of complex peaks are dealt with. In both cases, the calculation principle, then the systematic tests achieved in order to-prove their validity and determine their application ranges are described and finally some experimental results appropriate to illustrate their possibilities are presented. (author) [French] Le present rapport a pour objet l'etude de methodes de calcul applicables a l'analyse par spectrometrie gamma. On etudie d'abord l'analyse quantitative par la methode des moindres carres, completee par une correction de derive du gain. Puis on examine les pics d'absorption totale simples et la resolution des pics complexes. Dans les deux cas, on expose le principe des calculs et les essais systematiques effectues pour eprouver leur validite et definir leurs domaines d'application, ainsi que quelques resultats experimentaux propres a illustrer leurs possibilites.

Research on 3-D terrain correction methods of airborne gamma-ray spectrometry survey

International Nuclear Information System (INIS)

Liu Yanyang; Liu Qingcheng; Zhang Zhiyong

2008-01-01

The general method of height correction is not effectual in complex terrain during the process of explaining airborne gamma-ray spectrometry data, and the 2-D terrain correction method researched in recent years is just available for correction of section measured. A new method of 3-D sector terrain correction is studied. The ground radiator is divided into many small sector radiators by the method, then the irradiation rate is calculated in certain survey distance, and the total value of all small radiate sources is regarded as the irradiation rate of the ground radiator at certain point of aero- survey, and the correction coefficients of every point are calculated which then applied to correct to airborne gamma-ray spectrometry data. The method can achieve the forward calculation, inversion calculation and terrain correction for airborne gamma-ray spectrometry survey in complex topography by dividing the ground radiator into many small sectors. Other factors are considered such as the un- saturated degree of measure scope, uneven-radiator content on ground, and so on. The results of for- ward model and an example analysis show that the 3-D terrain correction method is proper and effectual. (authors)

Fried-Yennie gauge recalculation of the electron line induced radiative-recoil corrections to muonium hyperfine splitting

International Nuclear Information System (INIS)

Brook, V.Yu.; Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1989-01-01

A new analytic calculation of radiative-recoil corrections to muonium ground-state hyperfine splitting induced by electron line insertions is performed. The starting point of this calculation is presented by the Fried-Yennie gauge expression for the electron line factor. The final result confirms the one obtained previously from the apparently different expression in the Feynman gauge and removes the slight discrepancy which existed in the literature between the calculations in different gauges. (orig.)

Prise en charge des urgences au service d'accueil des urgences ...

African Journals Online (AJOL)

Introduction: La prise en charge des patients dans les services d'accueil des urgences est une des meilleures vitrines d'un système de santé. En Afrique subsaharienne, la gestion des urgences se heurte à des difficultés humaines et matérielles. Le but de ce travail était d'évaluer les difficultés de prise en charge au Service ...

Evaluation of a method for correction of scatter radiation in thorax cone beam CT

International Nuclear Information System (INIS)

Rinkel, J.; Dinten, J.M.; Esteve, F.

2004-01-01

Purpose: Cone beam CT (CBCT) enables three-dimensional imaging with isotropic resolution. X-ray scatter estimation is a big challenge for quantitative CBCT imaging of thorax: scatter level is significantly higher on cone beam systems compared to collimated fan beam systems. The effects of this scattered radiation are cupping artefacts, streaks, and quantification inaccuracies. The beam stops conventional scatter estimation approach can be used for CBCT but leads to a significant increase in terms of dose and acquisition time. At CEA-LETI has been developed an original scatter management process without supplementary acquisition. Methods and Materials: This Analytical Plus Indexing-based method (API) of scatter correction in CBCT is based on scatter calibration through offline acquisitions with beam stops on lucite plates, combined to an analytical transformation issued from physical equations. This approach has been applied with success in bone densitometry and mammography. To evaluate this method in CBCT, acquisitions from a thorax phantom with and without beam stops have been performed. To compare different scatter correction approaches, Feldkamp algorithm has been applied on rough data corrected from scatter by API and by beam stops approaches. Results: The API method provides results in good agreement with the beam stops array approach, suppressing cupping artefact. Otherwise influence of the scatter correction method on the noise in the reconstructed images has been evaluated. Conclusion: The results indicate that the API method is effective for quantitative CBCT imaging of thorax. Compared to a beam stops array method it needs a lower x-ray dose and shortens acquisition time. (authors)

Zur Struktur des deutschen Satzes. Systematische Betrachtung der einzelnen Satzpositionen unter didaktischen Gesichtspunkten

Directory of Open Access Journals (Sweden)

Dieter Schmid

2017-04-01

Full Text Available Die Struktur, d.h. die Syntax des deutschen Satzes ist möglicherweise das komplexeste Thema der deutschen Grammatik. Es scheint, dass die meisten Fehler in diesem Bereich gemacht werden, und selbst Muttersprachler und Muttersprachlerinnen sind oft unsicher bzgl. der richtigen Wortstellung, insbesondere im Mittelfeld des Satzes. Dieser Aufsatz versucht, Deutschlehrern und -lehrerinnen eine Hilfestellung zu geben, indem er − aufbauend auf das topologische oder Stellungsfeldermodell von Erich Drach (vgl. Musan 2009: 10 − die wichtigsten Stellungsregeln für die verschiedenen Satzelemente angibt. Dies geschieht dadurch, dass alle möglichen „Positionen“ des deutschen Satzes systematisch untersucht werden, eine nach der anderen. The structure, i.e., the syntax of the German sentence is perhaps the most complex topic of German grammar. It seems that most mistakes are made in this area, and even native speakers are often not sure about the correct word order, especially in the middle-field of the sentence. This paper tries to help German teachers by giving them − based on the topological field model of Erich Drach − the most important rules about the correct positioning of the different elements of the sentence. It does so by examining systematically all the possible “positions” of the German sentence, one after the other.

Semi-analytic approach to higher-order corrections in simple muonic bound systems: vacuum polarization, self-energy and radiative-recoil

Energy Technology Data Exchange (ETDEWEB)

Jentschura, U.D. [Department of Physics, Missouri University of Science and Technology, Rolla MO65409 (United States); Institut fur Theoretische Physik, Universitat Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); Wundt, B.J. [Department of Physics, Missouri University of Science and Technology, Rolla MO65409 (United States)

2011-12-15

The current discrepancy of theory and experiment observed recently in muonic hydrogen necessitates a reinvestigation of all corrections to contribute to the Lamb shift in muonic hydrogen ({mu}H), muonic deuterium ({mu}D), the muonic {sup 3}He ion (denoted here as {mu}{sup 3}He{sup +}), as well as in the muonic {sup 4}He ion ({mu}{sup 4}He{sup +}). Here, we choose a semi-analytic approach and evaluate a number of higher-order corrections to vacuum polarization (VP) semi-analytically, while remaining integrals over the spectral density of VP are performed numerically. We obtain semi-analytic results for the second-order correction, and for the relativistic correction to VP. The self-energy correction to VP is calculated, including the perturbations of the Bethe logarithms by vacuum polarization. Sub-leading logarithmic terms in the radiative-recoil correction to the 2S-2P Lamb shift of order {alpha}(Z{alpha}){sup 5{mu}3}ln(Z{alpha})/(m{sub {mu}mN}) where {alpha} is the fine structure constant, are also obtained. All calculations are nonperturbative in the mass ratio of orbiting particle and nucleus. (authors)

Connaissances, attitudes et pratiques des prestataires de santé des ...

African Journals Online (AJOL)

... des prestataires interrogés avaient respectivement une bonne connaissance des facteurs de risque et des moyens de dépistage. Les signes évocateurs et les examens complémentaires nécessaires au diagnostic du cancer du sein étaient connus par 15,3 % des prestataires. La définition du cancer du sein et les moyens ...

Foundations of radiation physics and radiation protection. 5. ed.; Grundlagen der Strahlungsphysik und des Strahlenschutzes

Energy Technology Data Exchange (ETDEWEB)

Krieger, Hanno

2017-07-01

The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

Radiative corrections to the triple Higgs coupling in the inert Higgs doublet model

International Nuclear Information System (INIS)

Arhrib, Abdesslam; Benbrik, Rachid; Falaki, Jaouad El; Jueid, Adil

2015-01-01

We investigate the implication of the recent discovery of a Higgs-like particle in the first phase of the LHC Run 1 on the Inert Higgs Doublet Model (IHDM). The determination of the Higgs couplings to SM particles and its intrinsic properties will get improved during the new LHC Run 2 starting this year. The new LHC Run 2 would also shade some light on the triple Higgs coupling. Such measurement is very important in order to establish the details of the electroweak symmetry breaking mechanism. Given the importance of the Higgs couplings both at the LHC and e + e − Linear Collider machines, accurate theoretical predictions are required. We study the radiative corrections to the triple Higgs coupling hhh and to hZZ, hWW couplings in the context of the IHDM. By combining several theoretical and experimental constraints on parameter space, we show that extra particles might modify the triple Higgs coupling near threshold regions. Finally, we discuss the effect of these corrections on the double Higgs production signal at the e + e − LC and show that they can be rather important.

Problems associated with the effects of low doses of ionising radiations

International Nuclear Information System (INIS)

Anon.

1996-01-01

This book is the English version of the report number 34 of the Academie des Sciences, published in October 1995, and entitled 'Problemes lies aux effets des faibles doses des radiations ionisantes'. This report had been endorsed by CODER (Comite des Etudes et Rapports) on February 7, 1995. In dealing with problems associated with ionising radiation, a wide range of important aspects must be taken into account and many different international bodies are concerned with them. It was therefore though useful to make the report available in English. Several additions have been made to the original edition: it has been complemented with three appendices on the cellular, molecular and genetic effects of exposure to low doses of ionising radiations ; it was though useful to give, in addition to the references of the chapters and appendices, a summary of the main relevant work published by French research teams over the past few years; an addendum quotes some of the important contributions made over the past year; a symposium devoted to the effects of low doses of ionising radiations, and to repair enzyme systems will be organized by the Academy at the end of 1997. This will provide the opportunity to re-explore the situation in the light of the data accumulated at that time. This field is evolving rapidly and a periodic evaluation of the new data is mandatory. (authors)

Usages des TIC et socialisation professionnelle des enseignants-chercheurs

OpenAIRE

Lavielle-Gutnik, Nathalie; Massou, Luc

2013-01-01

En prenant appui sur une nouvelle analyse des données recueillies dans l’enquête Tec-Meus (2008-2011, MSH Lorraine) sur la place accordée par des enseignants-chercheurs en sciences humaines et sociales aux technologies de l’information et de la communication (TIC) dans leur activité d’enseignement, nous souhaitons nous focaliser dans cet article sur la compréhension des processus de socialisation professionnelle en jeu dans leur usage déclaré des TIC. Par socialisation professionnelle, nous e...

Evaluer des études de gestion des entreprises : combiner des éléments principales avec des éléments pratiques

NARCIS (Netherlands)

Pennink, B.J.W.

2002-01-01

Evaluer la recherche de gestion demande une combinaison des critères classiques et des critères pratiques. Par cette combinaison il est possible de trouver une réponse cerrecte concernant la validité et l'effet de la recherche. Dans cet article nous allons décrire comment une combinaison des

Aspects des Onychomycoses chez des patients camerounais de ...

African Journals Online (AJOL)

... biologiques et évolutifs des onychomycoses chez des patients camerounais. Méthode : Il s'agit d'une étude rétrospective et descriptive menée de mars 2011 à mars 2014 dans l'unité de dermatologie de l'hôpital général de Douala (HGD), incluant des patients chez lesquels le diagnostic d'onychomycose avait été posé.

Correction of the Radiation Protection Ordinance

International Nuclear Information System (INIS)

1977-01-01

The tables IV (free limits, derived limiting values of annual activity supply for inhalation and ingestion and derived limiting values of activity concentrations in the air) and some spelling, unit and term mistakes are corrected. (HP) [de

Radiation Resistance of Enzymes in Foods Irradiated Against Microbial Damage; Radioresistance des Enzymes dans les Denrees Alimentaires Irradiees pour les Proteger Contre les Alterations Dues a des Bacteries; Radiatsionnaya ustojchivost' ehnzimov v pishchevykh produktakh,obluchennykh protiv vrednogo vozdejstviya mikrobov; Radiorresistencia de las Enzimas en los Alimentos Irradiados

Energy Technology Data Exchange (ETDEWEB)

Vas, K. [Joint FAO/IAEA Division of Atomic Energy in Agriculture, International Atomic Energy Agency, Vienna (Austria)

1966-11-15

Most enzymes which play a role in the storage, processing and preservation of food are rather resistant to ionizing radiations. Generally speaking, their in situ radio-resistance is about an order of magnitude higher than that of the microorganisms causing spoilage or public health hazards. Thus, radiation doses adequate to microbiological stabilization, and at present considered just feasible economically, are insufficient to prevent enzymatic deterioration. Many attempts have already been made to inactivate enzymes in food by radiation but, judging by the relative failure of most of these efforts, much more background information seems to be necessary to deal with the problem on a more rational basis. To date, work in radiation enzymology has, to a large extent, been carried out in systems of medical interest, generally giving results not readily transposable to food systems. In the past (a) the mechanism of inactivation, as well as the roles of (b) enzyme concentration, (c) water activity of the medium, (d) oxygen concentration, (e) pH and (f) temperature, have been studied most intensively. This is reviewed in the paper. Since, in the majority of the reported experiments, the degree of purity of the enzyme has not been stated (or known, for that matter to the authors themselves), and since, on the other hand, radio-modifying substances are known to exert a decisive influence on the radiation inactivation of enzymes, it is felt that much more work is still needed on radio-protectors and radiation sensitizers in combination with highly-purified enzymes. The usual great radio-sensitivity of high-purity enzymes and the contrasting extreme resistance of enzymes in the tissues and in their unpurified extracts certainly indicate the need for finding the reasons for this difference in order to facilitate possibly a rational approach of controlling enzyme activity in food irradiation. In this way, perhaps some novel ''combination method'' can eventually be developed in

Architecture, des normes et des systèmes d'information libres, phase ...

International Development Research Centre (IDRC) Digital Library (Canada)

Architecture, des normes et des systèmes d'information libres, phase II (OASIS II) - Renforcement des capacités dans l'ensemble de l'Afrique. Sur presque tout le continent africain, la prestation des services de santé est limitée en raison des maigres ressources disponibles et de la charge de morbidité de plus en plus ...

Method of evaluation of radiant heat transfers for geometries having cast shadows; Methode d`evaluation des echanges radiatifs pour des geometries comportant des ombres portees

Energy Technology Data Exchange (ETDEWEB)

Lair, P; Millan, P [ONERA-CERT/DERMES, 31 - Toulouse (France); Dumoulin, J [INSA-UPS, LETHEM, 31 - Toulouse (France)

1997-12-31

Experimental studies on aero-thermal characterization of various flows are carried out by the CERT/DERMES centre of the French national office of aerospace studies and research (ONERA). The measurement is based on the infrared thermography method which requires a correction of surface fluxes. This correction is necessarily based on a radiative statement of the cell where the flow takes place. A numerical method of form factors calculation in complex geometrical configuration has been developed. This method is applicable to surfaces (flat or not) and takes into account the shadow phenomena as they can exist inside an experimental test path. Two methods of radiative statements have been developed and compared. The influence of form factors calculation on the radiative statement is also analyzed and the problem of the sensitivity of the methods with respect to possible measurement errors is evoked. (J.S.) 8 refs.

Method of evaluation of radiant heat transfers for geometries having cast shadows; Methode d`evaluation des echanges radiatifs pour des geometries comportant des ombres portees

Energy Technology Data Exchange (ETDEWEB)

Lair, P.; Millan, P. [ONERA-CERT/DERMES, 31 - Toulouse (France); Dumoulin, J. [INSA-UPS, LETHEM, 31 - Toulouse (France)

1996-12-31

Experimental studies on aero-thermal characterization of various flows are carried out by the CERT/DERMES centre of the French national office of aerospace studies and research (ONERA). The measurement is based on the infrared thermography method which requires a correction of surface fluxes. This correction is necessarily based on a radiative statement of the cell where the flow takes place. A numerical method of form factors calculation in complex geometrical configuration has been developed. This method is applicable to surfaces (flat or not) and takes into account the shadow phenomena as they can exist inside an experimental test path. Two methods of radiative statements have been developed and compared. The influence of form factors calculation on the radiative statement is also analyzed and the problem of the sensitivity of the methods with respect to possible measurement errors is evoked. (J.S.) 8 refs.

L'exode des cerveaux et le renforcement des capacités en Afrique ...

International Development Research Centre (IDRC) Digital Library (Canada)

1 févr. 2011 ... Ce phénomène ébranle les assises économiques et politiques de bien des pays africains. ... le défi consiste à recruter ces cerveaux. ... des missions africaines, des organisations non gouvernementales et des groupes de la diaspora réunis pour parler de l'exode des cerveaux en Afrique et des stratégies à ...

Fluid Sampling under Adverse Conditions Echantillonnage des fluides en conditions difficiles

Directory of Open Access Journals (Sweden)

Williams J. M.

2006-12-01

Full Text Available Valid samples are essential to the proper description of reservoir fluids; if the samples are not representative, all measurements on them will be invalid. This paper discusses the principal challenges facing fluid sampling including gas condensate reservoirs, compositional gradients, water content of hydrocarbon fluids, asphaltene deposition, wax formation, oil base mud contamination, and reactive components. It also reports the major technological advances recently made in this field. It reviews developments in sampling techniques such as MDT-type tools, new DST sampling tools, coiled tubing sampling, and isokinetic techniques, and it highlights common limitations. The value of making proper use of existing technology is emphasized, both with traditional techniques and new developments, with reference to correct well conditioning, interpretation of field data, and especially to optimum handling of samples. The paper emphasizes the need for better exchange of sampling knowledge between organizations, and highlights the lack of up-to-date industry standards with respect to fluid sampling. A solution is proposed in the form of a joint industry project to identify and document best practices. Des échantillons valables sont essentiels pour bien caractériser les fluides de gisements. Si les échantillons ne sont pas représentatifs, toutes les mesures ultérieures seront entachées d'erreurs. Cet article discute les principaux défis en matière d'échantillonnage, en particulier les réservoirs de gaz à condensats, les gradients compositionnels, la teneur en eau des fluides hydrocarbonés, les dépôts d'asphaltènes, les dépôts de paraffines, la contamination par les boues à base d'huile, et les constituants réactifs. Il relate également les principaux progrès technologiques récemment réalisés dans ce domaine et passe en revue les développements des techniques d'échantillonnage telles que les outils de type MDT, les nouveaux outils d

Influence de l'occupation des terres sur la dynamique des ...

African Journals Online (AJOL)

L'objectif de la présente étude est d'évaluer l'impact de mise en culture, des pâturages, des jachères et l'influence des villages sur la dynamique des communautés végétales de la commune de ..... mais il n'y a que peu de recrutement. Au-delà de cinq ans, taille et phytovolume diminuent, témoignant du vieillissement de la ...

Studying radiative B decays with the Atlas detector; Etude des desintegrations radiatives des mesons B dans le detecteur ATLAS

Energy Technology Data Exchange (ETDEWEB)

Viret, S

2004-09-01

This thesis is dedicated to the study of radiative B decays with the ATLAS detector at the LHC (large hadron collider). Radiative decays belong to the rare decays family. Rare decays transitions involve flavor changing neutral currents (for example b {yields} s{gamma}), which are forbidden at the lowest order in the Standard Model. Therefore these processes occur only at the next order, thus involving penguin or box diagrams, which are very sensitive to 'new physics' contributions. The main goal of our study is to show that it would be possible to develop an online selection strategy for radiative B decays with the ATLAS detector. To this end, we have studied the treatment of low energy photons by the ATLAS electromagnetic calorimeter (ECal). Our analysis shows that ATLAS ECal will be efficient with these particles. This property is extensively used in the next section, where a selection strategy for radiative B decays is proposed. Indeed, we look for a low energy region of interest in the ECal as soon as the level 1 of the trigger. Then, photon identification cuts are performed in this region at level 2. However, a large part of the proposed selection scheme is also based on the inner detector, particularly at level 2. The final results show that large amounts of signal events could be collected in only one year by ATLAS. A preliminary significance (S/{radical}B) estimation is also presented. Encouraging results concerning the observability of exclusive radiative B decays are obtained. (author)

Studying radiative B decays with the Atlas detector; Etude des desintegrations radiatives des mesons B dans le detecteur ATLAS

Energy Technology Data Exchange (ETDEWEB)

Viret, S

2004-09-01

This thesis is dedicated to the study of radiative B decays with the ATLAS detector at the LHC (large hadron collider). Radiative decays belong to the rare decays family. Rare decays transitions involve flavor changing neutral currents (for example b {yields} s{gamma}), which are forbidden at the lowest order in the Standard Model. Therefore these processes occur only at the next order, thus involving penguin or box diagrams, which are very sensitive to 'new physics' contributions. The main goal of our study is to show that it would be possible to develop an online selection strategy for radiative B decays with the ATLAS detector. To this end, we have studied the treatment of low energy photons by the ATLAS electromagnetic calorimeter (ECal). Our analysis shows that ATLAS ECal will be efficient with these particles. This property is extensively used in the next section, where a selection strategy for radiative B decays is proposed. Indeed, we look for a low energy region of interest in the ECal as soon as the level 1 of the trigger. Then, photon identification cuts are performed in this region at level 2. However, a large part of the proposed selection scheme is also based on the inner detector, particularly at level 2. The final results show that large amounts of signal events could be collected in only one year by ATLAS. A preliminary significance (S/{radical}B) estimation is also presented. Encouraging results concerning the observability of exclusive radiative B decays are obtained. (author)

GENOMIQUE ET LIPIDES Génomique et métabolisme des lipides des plantes

Directory of Open Access Journals (Sweden)

Delseny Michel

2002-03-01

Full Text Available Il existe dans les bases de données publiques une énorme quantité de séquences d’ADN dérivées de plantes, et notamment la séquence complète du génome d’Arabidopsis thaliana, une plante modèle pour les oléagineux, proche parente du colza. Ces données constituent une ressource importante non seulement pour la compréhension de métabolisme lipidique et de sa régulation, mais aussi pour la sélection et le développement de variétés nouvelles d’oléagineux produisant davantage d’huiles ou des huiles de composition nouvelle. Cette abondance de séquences peut être exploitée, en utilisant les recherches d’homologies, pour identifier les gènes, pour obtenir des informations sur leur fonction, comme pour repérer des gènes candidats codant des fonctions nouvelles. L’analyse de ces bases de données a révélé que la majeure partie des gènes codant des enzymes impliquées dans le métabolisme lipidique appartient à des petites familles multigéniques, reflétant la diversification des fonctions des isoformes. Une analyse du catalogue des ADNc séquencés en aveugle reflète les niveaux d’expression des différents gènes et fournit un aperçu des régulations des flux au travers des voies métaboliques conduisant à la biosynthèse des lipides de réserve. La disponibilité de mutants et de lignées transgéniques d’Arabidopsis et le développement de puces à ADN qui permettent l’analyse simultanée de plusieurs milliers de gènes conduiront à une meilleure compréhension des facteurs qui régulent le métabolisme des huiles dans les graines. Une telle connaissance facilitera la manipulation de la composition des huiles et des quantités produites dans les graines.

Use of glasses as industrial dosimeters; Utilisation des verres comme dosimetres industriels

Energy Technology Data Exchange (ETDEWEB)

Balestic, F. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Le Clerc, P.; Bonnaud, M. [Centre de Recherches des Glaceries de Saint-Gobain (France)

1959-07-01

Glasses have the property of colouring under the action of ionizing radiations. We endeavoured to specify the conditions under which the intensity of coloration can be used as a measure of the quantity of radiation to which the glass has been submitted. In the case of a glass loaded with cobalt, a study of the optical density at different wavelengths enabled us to find the factors governing the formation of coloured centres and their conservation in the glass. We give a set of calibrating curves for different values of these parameters (irradiation rate, irradiation temperature; fading time and fading temperature), enabling determination of radiation doses in the range from 10 000 to 1 000 000 rep from measured optical density. (author) [French] Les verres ont la propriete de se colorer sous l'action des rayonnements ionisants. Nous avons cherche a preciser les conditions dans lesquelles l'intensite de la coloration peut servir de mesure de la quantite du rayonnement auquel le verre a ete soumis. Dans le cas d'un verre charge au cobalt, l'etude de la densite optique a differentes longueurs d'onde a mis en evidence divers facteurs dont depend la formation des centres colores et leur conservation dans le verre. En prenant comme parametres ces divers facteurs (temperature d'irradiation, intensite d'irradiation, temperature de conservation et duree de conservation) nous avons etabli des courus d'etalonnage permettant la determination de doses entre 10 000 et 1 000 000 rep d'apres la densite optique observee. (auteur)

Use of glasses as industrial dosimeters; Utilisation des verres comme dosimetres industriels

Energy Technology Data Exchange (ETDEWEB)

Balestic, F [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Le Clerc, P; Bonnaud, M [Centre de Recherches des Glaceries de Saint-Gobain (France)

1959-07-01

Glasses have the property of colouring under the action of ionizing radiations. We endeavoured to specify the conditions under which the intensity of coloration can be used as a measure of the quantity of radiation to which the glass has been submitted. In the case of a glass loaded with cobalt, a study of the optical density at different wavelengths enabled us to find the factors governing the formation of coloured centres and their conservation in the glass. We give a set of calibrating curves for different values of these parameters (irradiation rate, irradiation temperature; fading time and fading temperature), enabling determination of radiation doses in the range from 10 000 to 1 000 000 rep from measured optical density. (author) [French] Les verres ont la propriete de se colorer sous l'action des rayonnements ionisants. Nous avons cherche a preciser les conditions dans lesquelles l'intensite de la coloration peut servir de mesure de la quantite du rayonnement auquel le verre a ete soumis. Dans le cas d'un verre charge au cobalt, l'etude de la densite optique a differentes longueurs d'onde a mis en evidence divers facteurs dont depend la formation des centres colores et leur conservation dans le verre. En prenant comme parametres ces divers facteurs (temperature d'irradiation, intensite d'irradiation, temperature de conservation et duree de conservation) nous avons etabli des courus d'etalonnage permettant la determination de doses entre 10 000 et 1 000 000 rep d'apres la densite optique observee. (auteur)

Des dispositions responsables à prendre pour la protection des ...

African Journals Online (AJOL)

En considérant l'effet néfaste des maladies, des parasites, du changement climatique et d'autres facteurs environnementaux (les OGM par exemple) sur la survie des abeilles, la baisse de leurs populations dans certaines parties du monde ne saurait être attribuée aux seules pesticides. En plus, l'impact de ces derniers sur ...

Gestion des risques

CERN Document Server

Louisot, Jean-Paul

2009-01-01

Depuis le début du lie siècle, la gestion des risques connaît une véritable révolution culturelle. Jusqu'alors fonction technique, centrée autour de l'achat de couverture d'assurances, elle est devenue une discipline managériale et transversale : une valise d'instruments que chaque manager doit connaître et appliquer quels que soient son domaine de compétence et ses missions au sein de l'organisation. En effet, la gestion des risques est une culture qui doit être assimilée par chacun des acteurs. C'est précisément l'ambition des 101 questions rassemblées dans cet ouvrage : apporter à chaque manager d'entreprise, de collectivité, d'établissement de santé..., des réponses claires au " pourquoi " et au " comment " : Comment identifier les risques ? Comment analyser les risques ? Quels sont les objectifs de la gestion des risques ? Une carte des risques pour quoi faire ? Pourquoi faut-il financer les risques ? Les entreprises ont-elles des responsabilités pénales ? En quoi consiste la gestion...

Comportement des polluants des eaux pluviales urbaines en ...

African Journals Online (AJOL)

développement et la croissance des organismes vivant dans l'eau et particulièrement les micro- organismes. Le suivi des températures enregistrées oscille entre 9 et 16°C dans les trois sites d'observation durant la période ... de la lumière du soleil. Le site C est bien aéré et .... Effets de différents modes de gestion des eaux ...

Atmospheric correction of satellite data

Science.gov (United States)

Shmirko, Konstantin; Bobrikov, Alexey; Pavlov, Andrey

2015-11-01

Atmosphere responses for more than 90% of all radiation measured by satellite. Due to this, atmospheric correction plays an important role in separating water leaving radiance from the signal, evaluating concentration of various water pigments (chlorophyll-A, DOM, CDOM, etc). The elimination of atmospheric intrinsic radiance from remote sensing signal referred to as atmospheric correction.

Relativistic duality, and relativistic and radiative corrections for heavy-quark systems

International Nuclear Information System (INIS)

Durand, B.; Durand, L.

1982-01-01

We give a JWKB proof of a relativistic duality relation which relates an appropriate energy average of the physical cross section for e + e - →qq-bar bound states→hadrons to the same energy average of the perturbative cross section for e + e - →qq-bar. We show that the duality relation can be used effectively to estimate relativistic and radiative corrections for bound-quark systems to order α/sub s//sup ts2/. We also present a formula which relates the square of the ''large'' 3 S 1 Salpeter-Bethe-Schwinger wave function for zero space-time separation of the quarks to the square of the nonrelativistic Schroedinger wave function at the origin for an effective potential which reproduces the relativistic spectrum. This formula allows one to use the nonrelativistic wave functions obtained in potential models fitted to the psi and UPSILON spectra to calculate relativistic leptonic widths for qq-bar states via a relativistic version of the van Royen--Weisskopf formula

Caractérisation des plantes médicinales à flavonoïdes des marchés ...

African Journals Online (AJOL)

Les espèces guinéo-congolaises sont les plus abondantes et le mode de dissémination majoritaire des diaspores est la zoochorie. Les plantes à flavonoïdes les plus utilisées sont : Combretum micranthum, Aloe vera, Ageratum conyzoïdes et Cylicodiscus gabonensis. Elles rentrent dans le traitement de 73 maladies parmi ...

Boltzmann factor and Hawking radiation

International Nuclear Information System (INIS)

Ryskin, Gregory

2014-01-01

Hawking radiation has thermal spectrum corresponding to the temperature T H =(8πM) −1 , where M is the mass (energy) of the black hole. Corrections to the Hawking radiation spectrum were discovered by Kraus and Wilczek (1995) and Parikh and Wilczek (2000). Here I show that these corrections follow directly from the basic principles of thermodynamics and statistical mechanics. In essence, it is the Boltzmann factor that ought to be corrected; corrections to the Hawking (or any other) radiation spectrum then follow necessarily

Reactor Radiation Loops as Large Gamma Sources; Boucles d'irradiation des reacteurs nucleaires utilisees comme sources gamma intenses; Radiatsionnye kontury yadernykh reaktorov kak moshchnye gamma-istochniki; Empleo de circuitos de irradiacion de los reactores como fuentes gamma de gran intensidad

Energy Technology Data Exchange (ETDEWEB)

Ryabukhina, Yu. S.

1963-11-15

Since 1957, study and research on the' production of radiation loops has been going on in the Soviet Union. Methods for calculating such systems were worked out and the possibilities of various gamma carriers examined. Indium alloy loops, liquid at room temperature, were first selected for practical experiment. The behaviour of two eutectic indium alloys was studied in relation to certain constructional materials and at the beginning of 1960 the first test indium-gallium loop was operated. Further work led to the installation of a model indium-gallium loop in the IRT reactor of the Georgian SSR Academy of Sciences with an irradiation source activity of 100 g Ra equivalent and a test In-Ga-Sn loop in a channel of the IRT reactor at the Institute of Atomic Energy, USSR Academy of Sciences. Finally in 1962, a pilot In-Ga-Sn loop for semi-industrial radiation processes was put into service in the IRT reactor of the Latvian SSR Academy of Sciences; its maximum irradiation source activity was 30 000 g Ra equivalent. The paper has the following sections: (1) ''Radiation loop calculation'', summarizing the work done on the computation techniques involved. (2) ''A model In-Ga radiation loop for the IRT-2000 reactor in Tbilisi'', describing the loop in operation. (3) ''An In-Ga-Sn radiation loop for the Latvian SSR Academy of Sciences IRT Reactor'', describing the loop in operation. (4) ''Possibilities of further radiation loop development'', describing experiments and systems and giving calculations on the basis of which it is considered possible to build hard manganese and mobile liquid indium-alloy loops. (author) [French] Depuis 1957, on execute en Union sovietique des travaux en vue d'etudier et de construire des boucles d'irradiation. On a elabore des methodes permettant de les calculer et d'examiner les possibilites offertes par differents emetteurs gamma. Le choix a porte tout d'abord sur les boucles utilisant des alliages liquides d'indium a la temperature ambiante

New approach to high energy SU/sub 2L/ /times/ U1 radiative corrections

International Nuclear Information System (INIS)

Ward, B.F.L.

1988-07-01

We present a new approach to SU/sub 2L/ /times/ U 1 radiative corrections at high energies. Our approach is based on the infrared summation methods of Yennie, Frautschi and Suura, taken together with the Weinberg-'t Hooft renormalization group equation. Specific processes which have been realized via explicit Monte Carlo algorithms are e + e/sup /minus// → f/bar f/' + n(γ), f = μ, /tau/, d, s, u, c, b or t and e + e/sup /minus// → e + e/sup /minus// + n(γ), where n(γ), denotes multiple photo emission on an event-by-event basis. Exemplary Monte Carlo data are presented. 16 refs., 4 figs

On radiative corrections to supersymmetric Higgs boson masses and their implications for LEP searches

International Nuclear Information System (INIS)

Ellis, J.; Zwirner, F.

1991-01-01

We present calculations of the one-loop radiative corrections to the mass of the neutral CP-odd Higgs boson (A) in the minimal supersymmetric extension of the standard model, as well as to the neutral CP-even Higgs (h, H) masses and mixing angles. We use these results to recalculate the cross-sections for Higgs production at LEP in the h + (Z * + fanti f), h (H)Z 0 and h (H) A final states. We delineate the domains of parameter space accessible at LEP at the Z 0 peak and at LEP II with a center-of-mass energy of 180, 190 or 200 GeV. (orig.)

Cosmogenic nuclide shielding corrections determined via MCNPX radiation transport and spallation cross sections

Science.gov (United States)

Argento, D.; Reedy, R. C.; Stone, J. O.

2011-12-01

Cosmogenic Nuclides (CNs) are a critical new tool for geomorphology, allowing researchers to date Earth surface events and measure process rates [1]. Prior to CNs, many of these events and processes had no absolute method for measurement and relied entirely on relative methods. Reliable absolute measurement methods impact research constraining ice age extents and provide important climatic data via well constrained erosion rates, etc. [2]. Continuing to improve CN methods is critical for these sciences. Significant progress has been made in the last two decades in refining the method and reducing analytic uncertainties [1,3]. CRONUS-Earth, a collaboration of cosmogenic nuclide researchers, has been developing calibration data and scaling methods to provide a self-consistent platform for use in interpreting nuclide concentration values into geologic data. However, several aspects of the radiation cascade have been exceedingly difficult to measure empirically with either accuracy or spatial extent. One such aspect is the angular distribution of secondary cosmic rays that are energetic enough to produce cosmogenic nuclides via spallation. Researchers studying the angular distribution of such cosmic rays have usually described the distribution as (cos(Θ))^m. Currently, the standard corrections, assume an m of 2.3, which is based on very sparse data sets with very limited spatial and altitude variation [1,4,5]. Researchers using CNs must know the production rate at the sample location, and then make corrections for the portion of the sky that is blocked by nearby topography. If the shielding correction model currently used is too simplistic, this introduces error into the final results. In this study, a Monte Carlo method radiation transport code, MCNPX is used to model the Galactic Cosmic Ray (GCR) radiation impinging on the upper atmosphere and tracks the resulting secondary particles through a model of the Earth's atmosphere. Angle and energy distributions are

Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

Science.gov (United States)

Amrani, Salah

La fabrication de l'aluminium est realisee dans une cellule d'electrolyse, et cette operation utilise des anodes en carbone. L'evaluation de la qualite de ces anodes reste indispensable avant leur utilisation. La presence des fissures dans les anodes provoque une perturbation du procede l'electrolyse et une diminution de sa performance. Ce projet a ete entrepris pour determiner l'impact des differents parametres de procedes de fabrication des anodes sur la fissuration des anodes denses. Ces parametres incluent ceux de la fabrication des anodes crues, des proprietes des matieres premieres et de la cuisson. Une recherche bibliographique a ete effectuee sur tous les aspects de la fissuration des anodes en carbone pour compiler les travaux anterieurs. Une methodologie detaillee a ete mise au point pour faciliter le deroulement des travaux et atteindre les objectifs vises. La majorite de ce document est reservee pour la discussion des resultats obtenus au laboratoire de l'UQAC et au niveau industriel. Concernant les etudes realisees a l'UQAC, une partie des travaux experimentaux est reservee a la recherche des differents mecanismes de fissuration dans les anodes denses utilisees dans l'industrie d'aluminium. L'approche etait d'abord basee sur la caracterisation qualitative du mecanisme de la fissuration en surface et en profondeur. Puis, une caracterisation quantitative a ete realisee pour la determination de la distribution de la largeur de la fissure sur toute sa longueur, ainsi que le pourcentage de sa surface par rapport a la surface totale de l'echantillon. Cette etude a ete realisee par le biais de la technique d'analyse d'image utilisee pour caracteriser la fissuration d'un echantillon d'anode cuite. L'analyse surfacique et en profondeur de cet echantillon a permis de voir clairement la formation des fissures sur une grande partie de la surface analysee. L'autre partie des travaux est basee sur la caracterisation des defauts dans des echantillons d'anodes crues

La cire cuticulaire des grains de raisin et des feuilles de la vigne

Directory of Open Access Journals (Sweden)

F. RADLER

1968-06-01

Full Text Available Je voudrais parler ici des recherches que j'ai effectuées dans le cadre d'un programme de recherches de l'Organisation australienne de recherches (C.S.I.R.O.. Ce sont des recherches sur la structure, la composition chimique et le rôle de la cire cuticulaire des grains de raisins et des feuilles. Ces recherches ont été effectuées principalement lors de l'étude des problèmes relatifs au séchage des raisins pour la production des raisins. Cependant, l'importance de la cire cuticulaire ne se limite pas seulement au séchage des raisins, car elle concerne aussi l'œnologie et les problèmes de la conservation des raisins de table. Je pense donc que mon exposé peut présenter pour vous un certain intérêt.

Proton ejection project for Saturne; Projet d'ejection des protons de saturne

Energy Technology Data Exchange (ETDEWEB)

Bronca, G; Gendreau, G

1959-07-01

The reasons for choosing the ejection system are given. The characteristics required for the ejected beam are followed by a description of the ejection process, in chronological order from the viewpoint of the protons: movement of the particles, taking into account the various elements which make up the system (internal magnet, external magnet, quadrupoles, ejection correction coils, thin and thick cables,...) and specification of these elements. Then follows an estimation of the delay in manufacture and the cost of the project. Finally, the characteristics of the magnets and quadrupoles are listed in an appendix. (author) [French] On donne d'abord les raisons du choix du systeme d'ejection, puis le principe. Apres les caracteristiques requises pour le faisceau ejecte, on decrit le processus d'ejection selon l'ordre chronologique vu par les protons: mouvement des particules compte tenu des divers elements composant le systeme (aimant interne, aimant externe, quadrupoles, enroulements correcteurs ejection, cibles mince et epaisse,. ..) et cahier de charge de ces elements. On estime, ensuite les delais de realisation et le cout du projet. Enfin, un resume des caracteristiques des aimants et quadrupoles est donne en appendice. (auteur)

Full O(α) electroweak radiative corrections to e+e- → t anti t γ with GRACE-Loop

International Nuclear Information System (INIS)

Khiem, P.H.; Fujimoto, J.; Ishikawa, T.; Kaneko, T.; Kurihara, Y.; Shimizu, Y.; Kato, K.; Ueda, T.; Vermaseren, J.A.M.; Yasui, Y.

2013-01-01

We present the full O(α) electroweak radiative corrections to the process e + e - → t anti t γ at the International Linear Collider (ILC). The computation is performed with the help of the GRACE-Loop system. We present the total cross-section and the top quark forward-backward asymmetry (A FB ) as a function of the center-of-mass energy and compare them with the process e + e - → t anti t γ. We find that the value of A FB in t anti t γ production is larger than A FB in t anti t production. It is an important result for the measurement of the top quark forward-backward asymmetry at the ILC. Applying a structure function method, we also subtract the QED correction to gain the genuine weak correction in both the α scheme and the G μ scheme (δ W G μ ). We obtain numerical values for δ W G μ which are changing from 2 % to -24 % when we vary the center-of-mass energy from 360 GeV to 1 TeV. (orig.)

Electroweak radiative corrections in the SU(2) x U(1) standard model

International Nuclear Information System (INIS)

Hollik, W.

1986-01-01

This paper contains a discussion of the 1-loop renormalization of the standard model and applications of the radiative corrections to fermion processes. Thereby we restrict the discussion to leptonic processes since these allow the cleanest access to the more subtle parts of the theory avoiding theoretical uncertainties as far as possible. Actual measurements of the W +- ,Z masses and of sin 2 θ W already indicate the presence of higher order effects in electroweak processes between fermions. More accurate measurements in the near future colliders LEP and SLC will allow to test the standard model beyond the tree level. At the 1-loop level a big amount of work has already been done with a satisfactory agreement between the individual calculations for the standard processes: μ decays, ν-scattering, and e + e → μ + μ - . 38 refs

statut de la matiere organique des cambisols et des lixisols sous

African Journals Online (AJOL)

Administrateur

L'étude vise à évaluer la matière organique des Cambisols et des Lixisols sous formations naturelles de longue durée en zone climatique nord-soudanienne et à établir, les relations entre ... sont supérieures à celles des sols des zones sahélienne et sud-soudanienne. ... globale a eu une corrélation positive avec le pH.

Fiabilité des structures mécaniques adaptatives: effet de la panne des actionneurs ou des capteurs sur la stabilité

Science.gov (United States)

Fall, H.; Charon, W.; Kouta, R.

2002-12-01

Ces dernières décennies, des activités significatives dans le monde étaient dirigées autour du contrôle actif. Le but de ces recherches était essentiellement d'améliorer les performances, la fiabilité et la sécurité des systèmes. Notamment dans le cas des structures soumises à des vibrations aléatoires. D'importants travaux ont été consacré à l'utilisation des “matériaux intelligents” comme capteurs et actionneurs. Cette article propose l'analyse de la fiabilité des systèmes mécaniques en étudiant les pannes des actionneurs ou des capteurs. L'effet de ces pannes sur la stabilité et la performance du système y est démontré. Les méthodologies de conception y sont rappelées. Des exemples numériques sont fournis à travers le contrôle d'un panneau sous chargement dynamique pour illustrer la méthode proposée.

Évaluation des émissions de gaz à effet de serre des filières de traitement et de valorisation des boues issues du traitement des eaux usées

OpenAIRE

Reverdy, A.L.; Pradel, M.

2011-01-01

/ Ce rapport présente l'inventaire des différentes consommations énergétiques, en consommables et des GES pour chaque poste de traitement et de valorisation des boues issues du traitement des eaux usées.

The radiation age of meteorites; L'age des meteorites; Opredelenie vozrasta meteoritov s pomoshch'yu radiatsii; Edad de los meteoritos

Energy Technology Data Exchange (ETDEWEB)

Goebel, K; Schmidlin, P [European Organisation for Nuclear Research, Geneva (Switzerland)

1962-01-15

Radioisotopes produced by cosmic radiation in meteorites while travelling through space can be used to trace the history of these meteorites. The radioisotopes and the accumulated daughter-elements in the meteorite must be determined in order to evaluate how long the meteorite was exposed to cosmic radiation. (It must be assumed for this calculation that the flux of the cosmic radiation is constant with time.) Most often gaseous isotopes have been used for these measurements as they can be easily separated from the meteoric substance. In the reported work tritium and argon have been mainly used. From the ratio H{sup 3}/He{sup 3}, radiation ages from a few millions to several hundred millions of years have been found. The recent measurements made at the European Organisation for Nuclear Research (CERN) agree in principle with results from other sources. The probable errors from diffusion-losses of gas and the influence of shielding in the pre-atmospheric meteorite are discussed in the paper. By taking into consideration the measured cross-section for tritium production in the elements which form the meteorite, the values of the cosmic-ray flux in outer space can be determined. (author) [French] Les radioisotopes produits par les rayonnements cosmiques dans les meteorites circulant dans l'espace peuvent servir a reconstituer l'histoire de ces corps. Il faut mesurer les radioisotopes et les produits de filiation accumules dans la meteorite pour evaluer le temps pendant lequel la meteorite a ete exposee aux rayonnements cosmiques. (On considere alors que le flux des rayonnements cosmiques ne varie pas dans le temps.) Pour ces mesures, on se fonde le plus souvent sur les isotopes gazeux parce qu'il est facile de les separer de la substance meteorique. Dans les recherches qui font l'objet du present memoire, il s'agissait surtout du tritium et de l'argon. En partant du rapport {sup 3}H/{sup 3}He, on a pu evaluer des ages allant de quelques millions a plusieurs centaines

Renforcement de l'autonomie des collectivités au moyen des ...

International Development Research Centre (IDRC) Digital Library (Canada)

Cette subvention permettra au ministère des Communications et des Technologies de l'information de l'Égypte ainsi qu'au fonds spécial réservé aux TI de consolider le modèle actuel des clubs de TI en Égypte, par l'entremise de services d'assistance sur demande, d'activités de formation à l'intention du personnel des ...

L' approche des options stratégiques des acteurs dans i' etude des relations tu travail

OpenAIRE

López Pino, Carmen Marina

2011-01-01

Faire une analyse de la proposition analytique développée par le MIT (Masachussetts Institute of Tecnology) inspirée du concept des options stratégiques pour I' objet de cet article. En premier lieu, les sujets traités seront la problematique des relations du travail et les découvertes fondamentales des différentes recherches de I' equipe du MIT. Après, I' étude fait une courte présentatión sur I' approche des systémes de Dunlop dont I' èquipe cherche améliorer. Ensuite, sont présentés...

Radiation analysis devices, radiation analysis methods, and articles of manufacture

Science.gov (United States)

Roybal, Lyle Gene

2010-06-08

Radiation analysis devices include circuitry configured to determine respective radiation count data for a plurality of sections of an area of interest and combine the radiation count data of individual of sections to determine whether a selected radioactive material is present in the area of interest. An amount of the radiation count data for an individual section is insufficient to determine whether the selected radioactive material is present in the individual section. An article of manufacture includes media comprising programming configured to cause processing circuitry to perform processing comprising determining one or more correction factors based on a calibration of a radiation analysis device, measuring radiation received by the radiation analysis device using the one or more correction factors, and presenting information relating to an amount of radiation measured by the radiation analysis device having one of a plurality of specified radiation energy levels of a range of interest.

Radiative corrections to neutralino annihilation. Recent developments

International Nuclear Information System (INIS)

Herrmann, Bjoern

2010-11-01

Evaluating the relic density of dark matter is an interesting possibility to constrain the parameter space of new physics models. However, this calculation is affected by several sources of uncertainty. On the particle physics side, considerable progress has been made in the recent years concerning the calculation of the annihilation cross-section of dark matter, which is needed in this context. In particular, within the Minimal Supersymmetric Standard Model, the theoretical uncertainty has been reduced through the calculation of loop corrections. The present contribution gives an overview over the achievements that have been made in QCD corrections to neutralino pair annihilation. The numerical impact is illustrated for a few examples. (orig.)

Developpement des betons semi autoplacants a rheologie adaptee pour des infrastructures

Science.gov (United States)

Sotomayor Cruz, Cristian Daniel

Au cours des dernières décennies, les infrastructures canadiennes et québécoises comportent plusieurs structures en béton armé présentant des problèmes de durabilité dus aux conditions climatiques sévères, à la mauvaise conception des structures, à la qualité des matériaux, aux types des bétons choisis, aux systèmes de construction ou à l'existence d'événements incontrôlables. En ce qui concerne le choix du béton pour la construction des infrastructures, une vaste gamme de béton divisée en deux principaux types peut être utilisée: le béton conventionnel vibré (BCV) et le béton autoplaçant (BAP). Dans le cas d'un BCV, la consolidation inadéquate par vibration a été un problème récurrent, occasionnant des dommages structuraux. Ceci a conduit à une réduction de la durabilité et à une augmentation du coût d'entretien et de réparation des infrastructures. Rien que l'utilisation d'un BAP a des avantages tels que l'élimination de la vibration, la réduction des coûts de main d'oeuvre et l'amélioration de la qualité des structures, néanmoins, le coût initial d'un BAP par rapport à un BCV ne permet pas encore de généraliser son utilisation dans l'industrie de la construction. Ce mémoire présente la conception d'une nouvelle gamme de béton semi-autoplaçant pour la construction des infrastructures (BSAP-I) exigeant une vibration minimale. Il s'agit de trouver un équilibre optimal entre la rhéologie et le coût initial du nouveau béton pour conférer une bonne performance structurale et économique aux structures. Le programme expérimental établi a premièrement permis d'évaluer la faisabilité d'utilisation des BSAP-I pour la mise en place des piliers d'une infrastructure de pont à Sherbrooke. En plus, l'utilisation d'un plan d'expériences a permis l'évaluation de trois paramètres de formulation sur les propriétés des mélanges de BSAP-I à l'état frais et durci. Finalement, l'évaluation de la performance des

Early Post-Irradiation Changes in the Metabolism of Biogenic Amines; Les Changements Precoces du Metabolisme des Amines Biogenes apres Irradiation

Energy Technology Data Exchange (ETDEWEB)

Deanovic, Z [Institut Rudjer Boskovic, Zagreb, Yugoslavia (Croatia)

1971-03-15

There is accumulating evidence for the radiation-induced release of biogenic amines from their body stores. Having in mind the high patho-physiological activity of these ''local'' hormones and ''neuro-hormones'', it is reasonable to assume that they play an important role in the pathogenesis of the acute radiation syndrome. Under these pathological conditions the possible synergic and antagonistic effects of biogenic amines due to their complex interactions must be taken into consideration. The extent and dose-dependence of post-irradiation changes in the metabolism of histamine, serotonin, catecholamines and acetylcholine will be examined regarding particularly the search for biochemical indicators of radiation injury. The determination of bio-amines and their metabolites in urine seems to be a suitable method for following up those metabolic changes which could be of a biodosimetrical and/or prognostical value. Data published on this subject, obtained in experimental animals as well as in man, have been reviewed and the applicability of these tests is discussed. (author) [French] Des preuves se sont accumulees, qui demontrent que les amines biogenes sont liberees de leurs depots sous l'effet des rayonnements ionisants. Etant donne la grande activite pathophysiologique de ces hormones 'locales' et 'neurohormones', il est raisonnable de considerer que ces substances biogenes jouent un role important dans la pathogenese du syndrome aigu d'irradiation. Dans ces conditions pathologiques il faut tenir compte des effets synergiques et antagonistes des bio-amines, lies a des interactions compliquees. Les changements metaboliques en fonction de la dose recue font l'objet d'un examen qui englobe les alterations quantitatives de .'histamine, de la serotonine, des catecholamines et de l'acetylcholine et dont l'objectif est la recherche sur des indicateurs biochimiques de la lesion provoquee par l'irradiation. L'analyse des bio-amines et de leurs metabolites dans les urines

Libération des acides gras par autolyse enzymatique des triglycérides des graines oléoprotéagineuses

Directory of Open Access Journals (Sweden)

Alibert Gilbert

2001-01-01

Full Text Available Les acides gras produits par hydrolyse chimique des lipides des plantes sont des matériaux de base pour l’industrie des biocarburants, des lubrifiants, des plastiques, des détergents et également des adjuvants de préparations commerciales d’herbicides. Cependant les procédés actuels de production des acides gras sont hautement polluants et coûteux en énergie. Dans ce travail nous développons un nouveau procédé de production des acides gras mettant en œuvre des plantes génétiquement modifiées. Nous avons introduit dans le tabac, retenu comme plante modèle, une construction génétique comprenant un gène de lipase (de la levure Geotrichum candidum sous le contrôle d’un promoteur graine spécifique (promoteur AtEm1 d’Arabidopsis thaliana. Ce promoteur devrait permettre l’expression du gène de lipase au niveau de l’axe embryonnaire tandis que les lipides s’accumulent dans les corps lipidiques des cotylédons. Dans ces conditions, les lipides de la graine devraient être séparés de la lipase par une compartimentation tissulaire et ne pas interférer. Après broyage des graines on peut penser que la mise en contact des lipides et de la lipase conduira à la libération d’acides gras. Plusieurs transformants ont été produits par transfert de gène à l’aide d’Agrobacterium tumefaciens, quelques-uns d’entre eux exprimant, comme attendu, la lipase dans leurs graines. Trois clones (2, 19 et 43 présentent une activité lipase significative et ont été retenus pour des études complémentaires. Cependant l’activité enzymatique observée est faible et certains clones présentent un défaut de compartimentation entre l’enzyme et les lipides se traduisant par la production d’acides gras dans la graine intacte. Lorsque les graines du clone 43 sont broyées dans un tampon, des acides gras sont produits dans le milieu réactionnel, validant le procédé imaginé. De nouvelles constructions réalisées, soit

Investigation of radiative corrections in the scattering at 180 deg. of 240 MeV positrons on atomic electrons

International Nuclear Information System (INIS)

Poux, J.P.

1972-06-01

In this research thesis, after a recall of processes of elastic scattering of positrons on electrons (kinematics and cross section), and of involved radiative corrections, the author describes the experimental installation (positron beam, ionization chamber, targets, spectrometer, electronic logics associated with the counter telescope) which has been used to measure the differential cross section of recoil electrons, and the methods which have been used. In a third part, the author reports the calculation of corrections and the obtained spectra. In the next part, the author reports the interpretation of results and their comparison with the experiment performed by Browman, Grossetete and Yount. The author shows that both experiments are complementary to each other, and are in agreement with the calculation performed by Yennie, Hearn and Kuo

Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning

Directory of Open Access Journals (Sweden)

Indra J Das

2016-01-01

Full Text Available Modern treatment planning systems provide accurate dosimetry in heterogeneous media (such as a patient' body with the help of tissue characterization based on computed tomography (CT number. However, CT number depends on the type of scanner, tube voltage, field of view (FOV, reconstruction algorithm including artifact reduction and processing filters. The impact of these parameters on CT to electron density (ED conversion had been subject of investigation for treatment planning in various clinical situations. This is usually performed with a tissue characterization phantom with various density plugs acquired with different tube voltages (kilovoltage peak, FOV reconstruction and different scanners to generate CT number to ED tables. This article provides an overview of inhomogeneity correction in the context of CT scanning and a new evaluation tool, difference volume dose-volume histogram (DVH, dV-DVH. It has been concluded that scanner and CT parameters are important for tissue characterizations, but changes in ED are minimal and only pronounced for higher density materials. For lungs, changes in CT number are minimal among scanners and CT parameters. Dosimetric differences for lung and prostate cases are usually insignificant (<2% in three-dimensional conformal radiation therapy and < 5% for intensity-modulated radiation therapy (IMRT with CT parameters. It could be concluded that CT number variability is dependent on acquisition parameters, but its dosimetric impact is pronounced only in high-density media and possibly in IMRT. In view of such small dosimetric changes in low-density medium, the acquisition of additional CT data for financially difficult clinics and countries may not be warranted.

Paternité des articles et intérêts concurrents : une analyse des recommandations aux auteurs des journaux traitant de pratique pharmaceutique

Science.gov (United States)

Courbon, Ève; Tanguay, Cynthia; Lebel, Denis; Bussières, Jean-François

2014-01-01

RÉSUMÉ Contexte : La présence d’auteurs honorifiques et fantômes ainsi que les intérêts concurrents représentent des difficultés bien documentées, liées à la publication d’articles scientifiques. Il existe des lignes directrices encadrant la rédaction et la publication de manuscrits scientifiques, notamment celles de l’International Committee of Medical Journal Editors (ICMJE). Objectifs : L’objectif principal de cette étude descriptive et transversale visait à recenser les instructions portant sur la paternité des articles et les intérêts concurrents provenant des recommandations aux auteurs des journaux traitant de pratique pharmaceutique. L’objectif secondaire visait à déterminer des mesures correctrices pour une paternité des articles plus transparente. Méthode : La recherche a débuté par l’identification des journaux traitant de pratique pharmaceutique. La consultation des instructions aux auteurs des journaux a permis ensuite de recenser les recommandations destinées à éviter les problèmes de paternité des articles et d’intérêts concurrents. Finalement, les membres de l’équipe de recherche se sont consultés afin de définir des mesures correctrices possibles à l’intention des chercheurs. Résultats : Des 232 journaux traitant de pharmacie, 33 ont été définis comme traitant de pratique pharmaceutique. Un total de 24 (73 %) journaux mentionnaient suivre la politique de l’ICMJE, 14 (42 %) demandaient aux auteurs de remplir un formulaire de déclaration d’intérêts concurrents au moment de la soumission de l’article, 17 (52 %) présentaient une définition de la qualité d’auteur et 5 (15 %) demandaient de détailler les contributions de chaque auteur. Une grille de 40 critères a été élaborée pour définir l’attribution du statut d’auteur. Conclusion : Moins de la moitié des journaux demandait aux auteurs de transmettre un formulaire de déclaration des intérêts concurrents au moment de la

Contribution des radios communautaires a l'education des ...

African Journals Online (AJOL)

Contribution des radios communautaires a l'education des populations rurales pour un developpement durable au Benin: etude de cas. ... Journal de la Recherche Scientifique de l'Université de Lomé. Journal Home · ABOUT THIS JOURNAL ...

Rôle des germes parasites des bactéries pathogènes dans l'autoépuration des eaux

Directory of Open Access Journals (Sweden)

GUELIN A.

1969-04-01

Full Text Available Existence dans les eaux polluées de germes parasites qui s'attaquent aux bactéries pathogènes. Le pouvoir bactéricide des eaux polluées dû, en grande partie à la présence dans ces eaux de différents représentants des germes parasites. Possibilité d'application pratique des germes parasites pour l'assainissement des eaux polluées.

Heavy water reactors physics; Physique des reacteurs a eau lourde

Energy Technology Data Exchange (ETDEWEB)

Girard, Y; Lourme, P; Naudet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

particulieres aux reseaux comportant le refroidissement par gaz mesures de distributions fines de densite (indices de spectre, etc mesures sur des reseaux ou des echantillons comportant de l'uranium a des enrichissements differents ou du plutonium. Dans la deuxieme partie on passe en revue les etudes de caractere theorique. L'ensemble des resultats a permis d'asseoir des methodes de calcul qui ont accru notablement la comprehension des phenomenes neutroniques dans les reseaux, et d'etablir un formulaire rendant compte des experiences sur reseaux neufs et capable de predire correctement l'evolution des proprietes neutroniques du combustible avec l'irradiation. Quelques etudes particulieres aux reacteurs de puissance sont mentionnees. (auteurs)

Radiation monitoring device

International Nuclear Information System (INIS)

Sato, Toshifumi.

1993-01-01

The device of the present invention concerns a reactor start-up region monitor of a nuclear power plant. In an existent start-up region monitor, bias voltage is limited, if the reactor moves to a power region, in order to prevent degradation of radiation detectors. Accordingly, since the power is lower than an actual reactor power, the reactor power can not be monitored. The device of the present invention comprises a memory means for previously storing a Plateau's characteristic of the radiation detectors and a correction processing means for obtaining a correction coefficient in accordance with the Plateau's characteristic to correct and calculate the reactor power when the bias voltage is limited. With such a constitution, when the reactor power exceeds a predetermined value and the bias voltage is limited, the correction coefficient can be obtained by the memory means and the correction processing means. Corrected reactor power can also be obtained from the start-up region monitor by the correction coefficient. As a result, monitoring of the reactor power can be continued while preventing degradation of the radiation detector even if the bias voltage is limited. (I.S.)

Effets des extraits vegetaux sur la dynamique de populations des ...

African Journals Online (AJOL)

La présente étude se propose de trouver une alternative de l'utilisation des pesticides chimiques en testant l'effet insecticide des extraits aqueux des feuilles de Hyptis suaveolens, graines de Ricinus communis et de Azadirachta indica contre les ravageurs du niébé en conditions de champ en utilisant le cyperméthrine ...

Special concretes for protection in piles (1963); Les betons speciaux dans la protection des piles (1963)

Energy Technology Data Exchange (ETDEWEB)

Condat, M.J.; Lafore, P.; Rastoin, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1963-07-01

The report reviews the main concretes used for the protection of reactors. First are examined the general factors affecting the selection of concretes for protection; some of the general aspects of radiation attenuation (fast and thermal neutrons, {gamma}) are then recalled. After an enumeration of the qualities and defects of conventional concretes, desirable or possible improvements are proposed: introduction of heavy elements for increasing the efficiency with respect to fast neutrons and {gamma}; increase in the hydrogen content (as H{sub 2}O), addition of absorbent products (B, Li, rare earths) for thermal neutron capture. A list is given of the principal products used for this purpose. Finally there is a rapid review of the preparation, the stability with time, and the resistance to radiation and to heat. Appendices and tables give details and numerical values. Appendix 1 deals with the question of water in concretes. Appendix 2 gives a classification of concretes based mainly on their density. At the end, ten tables give the compositions and values of the physical and mechanical characteristics of sixteen particularly typical concretes. (authors) [French] Le rapport passe en revue les principaux betons utilisables pour la protection des reacteurs. On examine d'abord les facteurs generaux influencant la selection des betons de protection; on rappelle ensuite brievement les aspects generaux de l'attenuation des rayonnements (neutrons rapides, neutrons thermiques, {gamma}). Apres avoir rappele les qualites et les defauts des betons classiques, on fait ressortir les perfectionnements souhaitables ou necessaires: introduction d'elements lourds pour ameliorer l'efficacite contre les neutrons rapides et les {gamma}; augmentation de la teneur en H (en H{sub 2}O); addition de corps absorbants (B, Li, terres rares) pour capturer les neutrons thermiques. On enumere les principaux corps utilises a cet effet. On termine par un tres rapide apercu sur

Special concretes for protection in piles (1963); Les betons speciaux dans la protection des piles (1963)

Energy Technology Data Exchange (ETDEWEB)

Condat, M J; Lafore, P; Rastoin, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1963-07-01

The report reviews the main concretes used for the protection of reactors. First are examined the general factors affecting the selection of concretes for protection; some of the general aspects of radiation attenuation (fast and thermal neutrons, {gamma}) are then recalled. After an enumeration of the qualities and defects of conventional concretes, desirable or possible improvements are proposed: introduction of heavy elements for increasing the efficiency with respect to fast neutrons and {gamma}; increase in the hydrogen content (as H{sub 2}O), addition of absorbent products (B, Li, rare earths) for thermal neutron capture. A list is given of the principal products used for this purpose. Finally there is a rapid review of the preparation, the stability with time, and the resistance to radiation and to heat. Appendices and tables give details and numerical values. Appendix 1 deals with the question of water in concretes. Appendix 2 gives a classification of concretes based mainly on their density. At the end, ten tables give the compositions and values of the physical and mechanical characteristics of sixteen particularly typical concretes. (authors) [French] Le rapport passe en revue les principaux betons utilisables pour la protection des reacteurs. On examine d'abord les facteurs generaux influencant la selection des betons de protection; on rappelle ensuite brievement les aspects generaux de l'attenuation des rayonnements (neutrons rapides, neutrons thermiques, {gamma}). Apres avoir rappele les qualites et les defauts des betons classiques, on fait ressortir les perfectionnements souhaitables ou necessaires: introduction d'elements lourds pour ameliorer l'efficacite contre les neutrons rapides et les {gamma}; augmentation de la teneur en H (en H{sub 2}O); addition de corps absorbants (B, Li, terres rares) pour capturer les neutrons thermiques. On enumere les principaux corps utilises a cet effet. On termine par un tres rapide apercu sur la mise en oeuvre, la

La participation des femmes à la vie politique se traduit par des ...

International Development Research Centre (IDRC) Digital Library (Canada)

La participation des femmes à la vie politique se traduit par des économies locales plus vigoureuses. 08 juin 2016. Image. Des femmes assistent à une réunion d'un groupe d'entraide près d'. Edgard Rodriguez - IDRC. Des femmes assistent à une réunion d'un groupe d'entraide près d'Hyderabad, en Inde. Keenara ...

Incidence des prix et des taxes sur la consommation de produits du ...

International Development Research Centre (IDRC) Digital Library (Canada)

Incidence des prix et des taxes sur la consommation de produits du tabac en Argentine, en Bolivie et au Chili. Partout en Amérique du Sud, les adultes et les enfants font une grande consommation de tabac. Un nouveau projet de recherche se penchera sur les avantages et les limites des stratégies de fixation des prix et de ...

Study and industrial applications of the external slowing-down {beta}{sup -} radiation of the yttrium - 90; Etude et applications industrielles du rayonnement de freinage externe des {beta}{sup -} de l'yttrium - 90

Energy Technology Data Exchange (ETDEWEB)

Leveque, P; Martinelli, P; Chauvin, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

Inelastic scattering of the {beta}{sup -} particles on the nucleus gives place to the emission of a X-ray Bremsstrahlung radiation. In view of possible industrial applications, we studied the slowing-down radiation of {sup 90}(Sr + Y) sources in various materials. This pure {beta}{sup -} emitter of long period is in the fission products of uranium. Among of the industrial applications, these sources of weak X-rays energy can be used for the radiography of thin pieces, for measuring the thickness, or for the analysis by fluorescence. (M.B.) [French] La diffusion inelastique des particules {beta}{sup -} sur les noyaux donne lieu a l'emission d'un rayonnement X de freinage. En vue de possibles applications industrielles, nous avons etudie le rayonnement de freinage des sources {sup 90}(Sr + Y) dans divers materiaux. Cet emetteur {beta}{sup -} pur a longue periode se trouve dans les produits de fission de l'uranium. Parmi les applications industrielles a l'etude, ces sources de rayons X de faible energie peuvent etre utilisees pour la radiographie de pieces minces, la mesure d'epaisseurs, ou encore pour l'analyse par fluorescence. (M.B.)

Roles et taches des accompagnateurs des patients hospitalises ...

African Journals Online (AJOL)

Roles et taches des accompagnateurs des patients hospitalises dans le service de pneumo-phtysiologie au Centre Hospitalier Universitaire Yalgado Ouedraogo de ... Logistical support represented by material support, drug supply, cleaning of premises, and littering occupied respectively 100%, 91%, 42% and 73%.

Utilisation des mousses et des pâtes syntactiques pour combler les lacunes des poteries archéologiques

Directory of Open Access Journals (Sweden)

Viviane Bechoux

2008-10-01

Full Text Available Filling potteries missing parts with plaster raises now complex problems during the de-restoration treatments. Ceramics restorers have recurrently questions on the use of plaster in the field of archaeological ceramics restoration. Some researches point to the choice of other filling materials. At the present time other methods can be devised by proposing plaster replacement by a lightened composite material: syntactic foams and pastes.Le comblement des lacunes des poteries à partir du plâtre pose actuellement des problèmes complexes lors des traitements de dérestauration. Les restaurateurs de céramiques s'interrogent de manière récurrente sur l'utilisation du plâtre dans le domaine de la restauration des céramiques archéologiques. Des recherches s'orientent vers le choix d'autres matériaux d'obturation. Actuellement, d'autres méthodes peuvent être mises en place en proposant le remplacement du plâtre par un matériau composite allégé, les mousses et les pâtes syntactiques.

Développer le leadership dans des villes de l'Amérique latine et des ...

International Development Research Centre (IDRC) Digital Library (Canada)

Développer le leadership dans des villes de l'Amérique latine et des Caraïbes dans le contexte des changements climatiques. En raison des changements climatiques, de la croissance démographique et de l'urbanisation rapide non planifiée, les villes des pays en développement sont à la fois le principal déclencheur des ...

La Question de L'impunité des Auteurs de Violations des Droits de L'homme

Directory of Open Access Journals (Sweden)

Maria dos Remédios Fontes Silva

2010-10-01

Full Text Available Ce travail pretend faire reflechir à propos de la question de l'impunite des autorites de L'Etat face aux violations des droits de l'homme. On abordera cet egard: a le role de I'amnistie ble complicite des autoritesadministratives c la lenteur des procedures judicieuse.     L'analyse de cette question montre qui L'impunite des responsables des violations des droits de l'homme fait peser une menace sur I'ensemble du systeme de protection universelle des droits de l'homme.          On peut on conduire qu 'aucune societe que aspire à la democratie et ala justice ne peut se construire sur I'amoralite des crimes impunis et I'amnesie officielle.

Correction of spectral and temporal phases for ultra-intense lasers; Correction des phases spectrale et temporelle pour les lasers ultra-intenses

Energy Technology Data Exchange (ETDEWEB)

Salmon, E

2000-12-15

The discovery of new regimes of interaction between laser and matter requires to produce laser pulses presenting higher luminous flux density. The only solutions that allow us to reach important power (about ten peta-watts) imply the correction of non-linear effects before compressing the laser pulse so that we do not transfer the phase modulation to the amplitude modulation. The aim of this work is the correction of the spectral phase through the modulation of the temporal phase. The first chapter is dedicated to the review of the physical phenomena involved in the interaction of ultra-intense laser pulse with matter. The peta-watt laser operating on the LIL (integrated laser line), the prototype line of the Megajoule Laser, is described in the second chapter. The third chapter presents the method used and optimized for getting an absolute measurement of the spectral phase in our experimental configuration. The fourth chapter details the analogy existing between the spatial domain and the temporal domain particularly between diffraction and dispersion. This analogy has allowed us to benefit from the knowledge cumulated in the spatial domain, particularly the treatment of the aberrations and their impact on the focal spot and to use it in the temporal domain. The principle of the phase correction is exposed in the fifth chapter. We have formalized the correspondence of the phase modulation between temporal domain and the spectral domain for strongly stretched pulses. In this way a modulation of the temporal phase is turned into a modulation of the spectral phase. All the measurements concerning phases and modulation spectral phase correction are presented in the sixth chapter. In the last chapter we propose an extension of the temporal phase correction by correcting non-linear effects directly in the temporal phase. This correction will improve the performances of the peta-watt laser. Numerical simulations show that the temporal phase correction can lead to a

The Effect of Gamma Radiation on the Fertility and Longevity Of Dolichoderus Quadripunctatus (Hymenoptera: Formicoidea Dolichoderidae); Effets des Radiations Gamma sur la Fertilite et la Longevite des Colonies de Dolichoderus Quadripunctatus (Hymenoptere: Formicoidea Dolichoderidae)

Energy Technology Data Exchange (ETDEWEB)

Torossian, C. [Faculte des Sciences, Universite de Toulouse (France); Causse, R. [INRA, Station de Zoologie, Centre de Recherches Agronomiques du Sud-Est, Montfavet (France)

1968-06-15

la fertilite, d'irradiations gamma a des valeurs comprises entre 12 500 et 150 000 rad; les resultats obtenus sont donnes dans le memoire. Dans le cas des colonies exclusivement composees d'ouvrieres la courbe de mortalite est lineaire pour des valeurs comprises entre 150 000 et 50 000 rad. La DL 50 est atteinte en 4 jours pour la dose de 150 000 rad, et 16 jours pour la dose de 50 000 rad. Aux valeurs les plus faibles(12 500 rad) la DL 50 s'obtient apres 18 jours. Pour les colonies temoins la DL50 s'obtient en 30 jours environ. La fecondite, qui est habituellement reguliere et constante dans les colonies d'ouvrieres, est exprimee par le rapport QR = quotient reproducteur (nombre d'oeufs/nombre d'ouvrieres au debut de l'experience). Le QR des colonies temoins (n' ayant subi aucune irradiation) a pour valeur 1,60 environ. Le QR des colonies traitees varie entre 0 et 0,06. Ces valeurs extremement faibles montrent que les colonies traitees sont devenues pratiquement steriles. Cette sterilite est definitive, car jusqu'a l'extinction de la colonie, aucune ponte n' a pu etre observee dans les colonies irradiees. Dans les colonies avec reine, seules les reines subissent une irradiation gamma, aux valeurs de 50 000, 100 000 et 150 000 rad. Les resultats obtenus concernant la longevite montrent dans tous les cas une resistance considerablement plus elevee des femelles que pour les ouvrieres placees dans les memes conditions. Pour ce qui est de la fecondite, on observe chez les reines irradiees un ralentissement considerable et quasi immediat de leur ponte. Ce ralentissement est suivi dans les colonies par une reprise de la ponte des ouvrieres: la reine ne peut plus exercer l'inhibition de leur ponte. Par la suite, la fecondite des reines irradiees diminue et devient nulle 3 partir du 18{sup e} jour. Il n'y a plus de reprise de la ponte des reines par la suite. (author)

QCD-resummation and non-minimal flavour-violation for supersymmetric particle production at hadron colliders; Resommation des corrections radiatives QCD et violation de la saveur non-minimale pour la production de particules supersymetriques aupres des collisionneurs hadroniques

Energy Technology Data Exchange (ETDEWEB)

Fuks, B

2007-06-15

Cross sections for supersymmetric particles production at hadron colliders have been extensively studied in the past at leading order and also at next-to-leading order of perturbative QCD. The radiative corrections include large logarithms which have to be re-summed to all orders in the strong coupling constant in order to get reliable perturbative results. In this work, we perform a first and extensive study of the resummation effects for supersymmetric particle pair production at hadron colliders. We focus on Drell-Yan like slepton-pair and slepton-sneutrino associated production in minimal supergravity and gauge-mediated supersymmetry-breaking scenarios, and present accurate transverse-momentum and invariant-mass distributions, as well as total cross sections. In non-minimal supersymmetric models, novel effects of flavour violation may occur. In this case, the flavour structure in the squark sector cannot be directly deduced from the trilinear Yukawa couplings of the fermion and Higgs supermultiplets. We perform a precise numerical analysis of the experimentally allowed parameter space in the case of minimal supergravity scenarios with non-minimal flavour violation, looking for regions allowed by low-energy, electroweak precision, and cosmological data. Leading order cross sections for the production of squarks and gauginos at hadron colliders are implemented in a flexible computer program, allowing us to study in detail the dependence of these cross sections on flavour violation. (author)

Regulations concerning radiation protection and survey; Donnees de la surveillance et regles qui en resultent en matiere de protection contre les rayonnements

Energy Technology Data Exchange (ETDEWEB)

Duhamel,; Lavie,; Fitoussi, [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

will only be considered with regard to recuperation of uranium after simple machining. (author) [French] 1. L'utilisation croissante de l'energie nucleaire sous toutes ses formes a des fins pacifiques pose des problemes de securite vis-a-vis des travailleurs, des populations et des sites en general. Une etude comparee des risques d'irradiation auxquels le personnel du Commissariat a l'Energie atomique (CEA) a ete expose au cours de l'annee 1957 et des resultats du controle des radiations par les moyens de detection collectifs ou individuels montre que les installations du CEA ont une influence negligeable sur la sante, en raison de la surveillance exercee. 2. Cependant, quelques incidents de contamination et d'irradiation - sommairement indiques ainsi que la maniere dont ils ont ete regles - rendent necessaire l'elaboration d'une reglementation precise definissant les responsabilites respectives, au sein d'un etablissement nucleaire, des services utilisateurs et du Service charge de la Protection contre les Radiations, en matiere de prevention de la contamination. 3. Un ensemble coherent de regles pratiques de prevention et de protection relatives a la detention, la manipulation, le transport et le stockage de sources radioactives scellees ou non scellees, est presente. A cette fin, a partir des recommandations de la Commission Internationale de Protection Radiologique et compte tenu: - de leur nocivite radioactive; de leur activite specifique par unite de masse et du risque de contamination; les radioelements ont ete classes suivant le danger qu'ils presentent par rapport au plutonium. 4. Le Service charge de la Protection contre les Radiations intervient comme conseiller des la conception des laboratoires specialises et veille ensuite a ce que les prescriptions reglementaires de securite soient observees. 5. Des donnees elaborees, indispensables a la protection contre les rayonnements, sont mises a la disposition des utilisateurs en particulier: - table des radio

Membrane fluidization by alcohols inhibits DesK-DesR signalling in Bacillus subtilis.

Science.gov (United States)

Vaňousová, Kateřina; Beranová, Jana; Fišer, Radovan; Jemioła-Rzemińska, Malgorzata; Matyska Lišková, Petra; Cybulski, Larisa; Strzałka, Kazimierz; Konopásek, Ivo

2018-03-01

After cold shock, the Bacillus subtilis desaturase Des introduces double bonds into the fatty acids of existing membrane phospholipids. The synthesis of Des is regulated exclusively by the two-component system DesK/DesR; DesK serves as a sensor of the state of the membrane and triggers Des synthesis after a decrease in membrane fluidity. The aim of our work is to investigate the biophysical changes in the membrane that are able to affect the DesK signalling state. Using linear alcohols (ethanol, propanol, butanol, hexanol, octanol) and benzyl alcohol, we were able to suppress Des synthesis after a temperature downshift. The changes in the biophysical properties of the membrane caused by alcohol addition were followed using membrane fluorescent probes and differential scanning calorimetry. We found that the membrane fluidization induced by alcohols was reflected in an increased hydration at the lipid-water interface. This is associated with a decrease in DesK activity. The addition of alcohol mimics a temperature increase, which can be measured isothermically by fluorescence anisotropy. The effect of alcohols on the membrane periphery is in line with the concept of the mechanism by which two hydrophilic motifs located at opposite ends of the transmembrane region of DesK, which work as a molecular caliper, sense temperature-dependent variations in membrane properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Photonique des Morphos

CERN Document Server

Berthier, Serge

2010-01-01

La photonique est déjà présente dans notre vie quotidienne, et on attend maintenant que la manipulation des photons permette aussi le traitement logique des informations. Cependant, l’élément de base qui permet cette manipulation de la lumière, le cristal photonique, est d’une réalisation complexe et mal contrôlée. Dans la course à la maîtrise de la lumière, les structures photoniques naturelles ont beaucoup à nous apprendre. C’est ce que nous montre Serge Berthier qui étudie dans ce livre la structure des écailles des Morphos. Tenant compte de l’essor récent des approches biomimétiques, il présente de manière détaillée plus de dix-huit techniques expérimentales utilisées pour ses analyses, ainsi que les diverses approches théoriques développées pour la modélisation de structures multi-échelles complexes. Première étude quasi-exhaustive des structures fines d’un genre et des propriétés optiques ainsi que colorimétriques générées, ce livre fournit aux entomologiste...

Screening phytochimique et identification spectroscopique des ...

African Journals Online (AJOL)

Origin

plante, effectuée pour la première fois, a révélé la présence des alcaloïdes, des flavonoïdes, des tanins catéchiques, des terpènes, des coumarines et des composés cyanogénétiques. Quant aux saponines et les quinones libres, ils sont présents chez les fleurs et absents chez les feuilles. La caractérisation des molécules.

Etude du processus de changement vecu par des familles ayant decide d'adopter volontairement des comportements d'attenuation des changements climatiques

Science.gov (United States)

Leger, Michel T.

Les activites humaines energivores telles l'utilisation intensive de l'automobile, la surconsommation de biens et l'usage excessif d'electricite contribuent aux changements climatiques et autres problemes environnementaux. Bien que plusieurs recherches rapportent que l'etre humain est de plus en plus conscient de ses impacts sur le climat de la planete, ces memes recherches indiquent qu'en general, les gens continuent a se comporter de facon non ecologique. Que ce soit a l'ecole ou dans la communaute, plusieurs chercheurs en education relative a l'environnement estiment qu'une personne bien intentionnee est capable d'adopter des comportements plus respectueux de l'environnement. Le but de cette these etait de comprendre le processus d'integration de comportements d'attenuation des changements climatiques dans des familles. A cette fin, nous nous sommes fixe deux objectifs : 1) decrire les competences et les procedes qui favorisent l'adoption de comportements d'attenuation des changements climatiques dans des familles et 2) decrire les facteurs et les dynamiques familiales qui facilitent et limitent l'adoption de comportements d'attenuation des changements climatiques dans des familles. Des familles ont ete invitees a essayer des comportements personnels et collectifs d'attenuation des changements climatiques de sorte a integrer des modes de vie plus ecologiques. Sur une periode de huit mois, nous avons suivi leur experience de changement afin de mieux comprendre comment se produit le processus de changement dans des familles qui decident volontairement d'adopter des comportements d'attenuation des changements climatiques. Apres leur avoir fourni quelques connaissances de base sur les changements climatiques, nous avons observe le vecu de changement des familles durant huit mois d'essais a l'aide de journaux reflexifs, d'entretiens d'explicitation et du journal du chercheur. La these comporte trois articles scientifiques. Dans le premier article, nous presentons une

Phase analysis and focusing of synchrotron radiation

CERN Document Server

Chubar, O; Snigirev, A

1999-01-01

High accuracy calculations of synchrotron radiation (SR) emitted by a relativistic electron show that the phase of the frequency domain electric field of SR differs from the phase of radiation of a virtual point source. These differences may result in the reduction of focusing efficiency of diffraction-limited SR, if the focusing is performed by conventional optical components optimised for point sources. We show that by applying a phase correction locally, one may transform the phase of SR electric field at a desired polarisation to that of a point source. Such corrections are computed for undulator radiation (planar and helical) and bending magnet radiation (central part and edges). The focusing of the corrected SR wavefront can result in the increase of peak intensity in the focused spot up to several times compared to the focusing without correction. For non-diffraction-limited radiation, the effect of the phase corrections is reduced. Due to this reason, the use of the proposed phase corrections in exist...

Study of thick, nuclear-compensated silicon detectors; Etude des detecteurs epais au silicium compense nucleairement

Energy Technology Data Exchange (ETDEWEB)

Le Coroller, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-09-01

A study is made here, from the point of view of the realization and the performance, of thick nuclear-compensated silicon detectors. After recalling the need for compensation and reviewing the existing methods, the author describes in detail the controlled realization of thick detectors by nuclear compensation from the theoretical and experimental points of view. The practical precautions which should be observed are given: control of the homogeneity of the starting material, control of the evolution of the compensation, elimination of parasitic processes. The performances of the detectors obtained are then studied: electrical characteristics (current, life-time) on the one hand, detection and spectrometry of penetrating radiations on the other hand. The results show, that the compensated diodes having an effective thickness of two millimeters operate satisfactorily as detectors for applied voltages of about 500 volts. The resolutions observed are then about 2 per cent for mono-energetic electrons and about 4 per cent for the gamma; they can be improved by the use of a pre-amplifier of very low background noise. (author) [French] Les detecteurs epais au silicium compense nucleairement sont etudies ici du double point de vue realisation et performances. Apres un rappel sur la necessite de la compensation et les procedes existants, la realisation controlee des detecteurs epais par compensation nucleaire est decrite en detail sous l'aspect theorique et l'aspect experimental. On met en evidence les precautions a prendre dans la pratique: controle de l'homogeneite du materiau de base, controle de l'evolution de la compensation, elimination des processus parasites. On etudie ensuite les performances de detecteurs obtenus : caracteristiques electriques (courant, duree de vie) d'une part, d'autre part detection et spectrometrie des rayonnements penetrants. Les resultats montrent que les diodes compensees ayant une epaisseur utile de deux

Study of thick, nuclear-compensated silicon detectors; Etude des detecteurs epais au silicium compense nucleairement

Energy Technology Data Exchange (ETDEWEB)

Le Coroller, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-09-01

A study is made here, from the point of view of the realization and the performance, of thick nuclear-compensated silicon detectors. After recalling the need for compensation and reviewing the existing methods, the author describes in detail the controlled realization of thick detectors by nuclear compensation from the theoretical and experimental points of view. The practical precautions which should be observed are given: control of the homogeneity of the starting material, control of the evolution of the compensation, elimination of parasitic processes. The performances of the detectors obtained are then studied: electrical characteristics (current, life-time) on the one hand, detection and spectrometry of penetrating radiations on the other hand. The results show, that the compensated diodes having an effective thickness of two millimeters operate satisfactorily as detectors for applied voltages of about 500 volts. The resolutions observed are then about 2 per cent for mono-energetic electrons and about 4 per cent for the gamma; they can be improved by the use of a pre-amplifier of very low background noise. (author) [French] Les detecteurs epais au silicium compense nucleairement sont etudies ici du double point de vue realisation et performances. Apres un rappel sur la necessite de la compensation et les procedes existants, la realisation controlee des detecteurs epais par compensation nucleaire est decrite en detail sous l'aspect theorique et l'aspect experimental. On met en evidence les precautions a prendre dans la pratique: controle de l'homogeneite du materiau de base, controle de l'evolution de la compensation, elimination des processus parasites. On etudie ensuite les performances de detecteurs obtenus : caracteristiques electriques (courant, duree de vie) d'une part, d'autre part detection et spectrometrie des rayonnements penetrants. Les resultats montrent que les diodes compensees ayant une epaisseur utile de deux millimetres fonctionnent

L'accumulation des métaux lourds au niveau des cultures : Cas des ...

African Journals Online (AJOL)

Le Bassin de Sebou présente une importance socio-économique pour le Maroc. En effet, il est sujet de diverses utilisations ; eau potable, eau d'irrigation et eau industrielle. Toutefois, ce bassin subit des pressions multiples, notamment par la pollution métallique. Considérant le risque de bioaccumulation des métaux par ...

Contribution to the study of the action of electromagnetic fields on the angular correlations of nuclear radiation (1960); Contribution a l'etude de l'action des champs electromagnetiques sur les correlations angulaires des rayonnements nucleaires (1960)

Energy Technology Data Exchange (ETDEWEB)

Lehmann, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-01-15

This work deals with the study of interaction of E.M. fields with nuclear moments of nuclei emitting gamma rays. We describe first experiments on delayed angular correlation showing the role played by statistic quadrupole interaction. We have measured the magnetic moment of the second excited state of {sup 19}F using an external magnetic field. In the case of {sup 19}O, experiments of angular distributions and angular correlations of gamma -rays taking into account the possibility of perturbations, allow us to determine the spin and parities of the three first levels. (author) [French] Le present travail concerne l'etude de l'interaction des champs electromagnetiques et des moments nucleaires de noyaux emettant des rayonnements gamma. Nous decrivons des experiences de correlation angulaire differee dont l'interpretation met en coincidence le role joue par les interactions quadrupolaires statiques. Nous avons mesure le moment magnetique de {sup 19}F dans un etat excite en utilisant un champ magnetique exterieur a la source radioactive. Enfin, dans le cas de {sup 19}O, nous montrons l'utilite d'un examen des possibilites de perturbations dans l'interpretation des resultats fournis par des correlations ou des distributions angulaires. (auteur)

Etude microdosimetrique de l'influence des materiaux sur l'efficacite biologique d'une source d'iode-125

Science.gov (United States)

Taschereau, Richard

Cette these concerne les implants permanents pour la prostate. Les isotopes employes, le 103Pd et l'125I, semblent produire les memes resultats cliniques: le premier a cause d'une radiation plus efficace et le second a cause de sa demi-vie plus longue. La recherche utilise le cadre theorique de la microdosimetrie et des simulations Monte Carlo. Elle propose d'employer le spectre d'ejection dans le calcul de l'efficacite; ce changement fait passer l'efficacite relative du 103Pd de 10% a 5%. Elle montre ensuite qu'il est possible d'ameliorer l'efficacite de la radiation de 125I par l'exploitation des rayons X caracteristiques de la capsule. Une source amelioree faite de molybdene et d'yttrium est donnee en exemple. Elle procure une radiation de 5--7% plus efficace, ce qui surclasse les deux sources existantes. Les applications ne se limitent pas au traitement de la prostate; le traitement du melanome oculaire et la curietherapie endovasculaire pourraient en beneficier.

Contribution des TICs à l'abandon des mutilations génitales ...

International Development Research Centre (IDRC) Digital Library (Canada)

Contribution des TIC à l'abandon des MGF en Afrique de l'Ouest francophone : rôle des jeunes citoyennes; rapport technique no. 5 (rapport technique final), 18 octobre 2008 - 31 mars 2009. Download PDF. Related content. New website will help record vital life events to improve access to services for all. A new website ...

utilisation des donnees pour l'evaluation de l'heterogeneite des sols

African Journals Online (AJOL)

AISA

étude a permis de caractériser l'hétérogénéité des sols ferrallitiques, à travers sa couleur. Mots-clés : Couleur ... ainsi qu'à l'application des recommandations des doses de fertilisant. ..... de « système sol » en zone de contact forêt- savane du ...

Intégration des données de l'atlas des marais atlantiques alimentés en eau de mer dans un système d'information à référence spatiale

OpenAIRE

Loubersac, Lionel; Manaud, Francois; Loarer, Ronan; Kerdreux, Michel; Durand, Christophe

1998-01-01

Ce papier décrit une méthodologie d’intégration des données analogiques d’un Atlas des marais salés atlantiques dans un SIG. On développe les différentes étapes de la méthode après avoir décrit les données originales sources sous forme de cartographie analogique thématique et de textes associés. Ces étapes incluent la digitalisation, les corrections géométriques, la définition d’une typologie et d’attributs, la mise en place de liens entre les graphiques, textes et images, le croisement de co...

Neutron borehole logging correction technique

International Nuclear Information System (INIS)

Goldman, L.H.

1978-01-01

In accordance with an illustrative embodiment of the present invention, a method and apparatus is disclosed for logging earth formations traversed by a borehole in which an earth formation is irradiated with neutrons and gamma radiation produced thereby in the formation and in the borehole is detected. A sleeve or shield for capturing neutrons from the borehole and producing gamma radiation characteristic of that capture is provided to give an indication of the contribution of borehole capture events to the total detected gamma radiation. It is then possible to correct from those borehole effects the total detected gamma radiation and any earth formation parameters determined therefrom

Les lexiques des jeunes dans les discours écrits des blogs : pour une approche descriptive

Directory of Open Access Journals (Sweden)

Lorenz Paulina

2014-07-01

Full Text Available S’il ne faut pas confondre ce qui est appelé communément « langage SMS » et « langage des jeunes », nous avancerons toutefois que les pratiques langagières écrites des jeunes sur les supports modernes de communication, et notamment dans les blogs, présentent des particularités encore peu étudiées. Les traits observables les plus saillants sont ceux de la morphologie graphique, mais il n’en reste pas moins que certains jeunes utilisent des lexiques particuliers dans les blogs qui méritent une attention particulière. Nous nous proposons donc d’étudier les différents lexiques utilisés par des jeunes de 12 à 22 ans dans les blogs de la plateforme skyrock.com aux niveaux de sa diversité, de ses usages sémantiques variable d’un scripteur à l’autre pour un même mot, et de ses particularités morphosyntaxiques. En effet, nous observerons des lexiques divers allant des lexiques perçus comme relevant des cités à des lexiques perçus comme étant « branchés-jeunes », ou encore à des lexiques propres aux supports modernes de communication. Ainsi, nous analyserons des lexiques variés dans leurs usages écrits tels que bolos, bédave, gérer, ouf, tigen, ou encore des lexiques empruntés tels que mouv, full, etc., ainsi que des emplois particuliers de séquences autonomes comme lol. Quelques questions périphériques complèteront notre analyse telle que celles qui concerne l’influence des usages lexicaux entre pairs et le savoir partagé, la distinction de différentes communautés en fonction des lexiques utilisés, ou encore la variabilité des représentations graphiques d’un même mot.

Méthode d'estimation des tassements des sols fins sous les remblais d'infrastructures ferroviaires pour lignes à grande vitesse

Science.gov (United States)

Said Alami, Soukaina; Reiffsteck, Philippe; Cuira, Fahd

2018-02-01

Le besoin de maîtriser les déformations des sols sous les remblais destinés à recevoir les structures de lignes à grande vitesse, en fait un enjeu important pour ces projets. Toutefois, de nombreuses difficultés ont été soulevées liées principalement au grand nombre d'incertitudes qui entourent le phénomène. En effet, la caractérisation géologique et géotechnique dépend de sondages et d'essais où le risque de remaniement est important et dont l'interprétation est, souvent, délicate. Cet article présente une procédure de calcul qui permettrait en pratique d'évaluer le tassement sous remblai avec une bonne précision et qui a été validée sur un certain nombre d'ouvrages. Pour cela, des corrections sont introduites aux méthodes usuelles de calcul permettant d'approcher les valeurs mesurées sur chantier.

Etat des lieux des soins de premier recours des malades mentaux à Antananarivo : étude rétrospective

Science.gov (United States)

Bakohariliva, Hasina Andrianarivony; Rafehivola, Imisanavalona Hanitrinihaja; Raobelle, Evah Norotiana; Raharivelo, Adeline; Rajaonarison, Bertille Hortense

2018-01-01

Résumé Religion et guérisseurs traditionnels occupent encore une place prépondérante dans la prise en charge des maladies mentales à Madagascar. Ainsi, nous nous sommes fixés comme objectif d'établir un état des lieux sur les soins de premier recours des malades mentaux. Nous avons mené une étude rétrospective descriptive s'étalant sur une période de 16 mois allant de janvier 2014 en avril 2015 au sein du service de psychiatrie du CHU de Befelatanana à Antananarivo. La prévalence des psychoses était de 25%. Le genre féminin (53%), l'ethnie merina (77%), les étudiants (45%), le niveau d'étude secondaire (40%), les célibataires (72%), la religion protestante (45%), ainsi que le niveau socio-économique moyen (57,5%) étaient prédominants. Dans les paramètres cliniques, le mode de début brutal (52%), le premier recours à la religion (40%), la présence d'antécédents des cas similaire (90%), étaient majoritaires. La schizophrénie était la pathologie la plus rencontrée dans la moitié des cas. Le délai d'amélioration en cas de traitement religieux et traditionnels était dans la moitié des cas de plus de 10 jours d'hospitalisation. Les patients ayant reçu une prise en charge psychiatrique en premier recours, étaient améliorés dans 75 % cas en moins de 10jours. Le retard du recours aux soins psychiatriques est une réalité à Madagascar qui aggrave le pronostic des psychoses. PMID:29632623

Accès à l'eau : des solutions techniques et sociales aident des ...

International Development Research Centre (IDRC) Digital Library (Canada)

Grâce à la modélisation par ordinateur faisant appel à des techniques de pointe et à la consultation des collectivités, l'organisme bolivien Agua Sustentable a trouvé des solutions politiques à des conflits qui auraient pu s'avérer désastreux au sujet de l'accès à l'eau. Cet organisme de recherche subventionné par le CRDI a ...

Le Débat des semences

International Development Research Centre (IDRC) Digital Library (Canada)

Solutions pour les lois nationales régissant le contrôle des ressources génétiques et des ...... des pouvoirs) qui reconnaissent, dans une certaine mesure, les droits de gestion collectifs des ...... documentés, les performances physiques, etc.

About the problem of the delays between particles belonging to the cosmic radiation; Sur le probleme des retards entre des particules appartenant au rayonnement cosmique

Energy Technology Data Exchange (ETDEWEB)

Rogozinski, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1953-07-01

After having examined briefly the problem of the delays who can appear between particles of high energy, issued of a same mother particle, we studied in a more details the case of the loaded particles, loosing their energy by ionization. The delay that settles between two particles of mass M belonging to this last species is defined by the difference between the times that they take to do the same distance. In the vacuum, the delays can reach any values. But, when the particles diffuse themselves in a middle absorbing, the delays stretch toward a definite limit whatever the initial energies of the particles is. One demonstrates that the maximum delay is given by ({delta}t){sub max} {approx_equal} 0,6 E{sub 0} / cK{sub min}, where E{sub 0} = Mc{sup 2} represents the energy to the rest of the particle and K{sub min} the minimum loss of energy by cm of course in the given middle. For example, in the case of the protons crossing different absorbing surroundings, the values of ({delta}t){sub max} for air (Tpn), water, the Al and the Pb are respectively equal to 8,3.10{sup -6}, 9,7.10{sup -9}, 45.10{sup -9} and 1,6 10{sup -9} dry. The corresponding values of ({delta}t){sub max} for the electrons, are the order of 10{sup -9} dry for air and the order of 10{sup -12} dry for the condensed surroundings. It results that, if the particles belonging has a sheaf demonstrated between them of the superior delays to those that are indicate, the fact would constitute a sufficient proof of the existence of heavy particles to the breast of the sheaf. Otherwise, the relation that joins ({delta}t){sub max} to the mass M could act as basis to a method of mass spectrography of the big energy particles. (author) [French] Apres avoir examine succintement le probleme des retards qui peuvent apparaitre entre des particules de grande energie, issues d'une meme particule mere, on etudie d'une facon plus detaillee le cas des particules chargees, ne perdant leur energie que par ionisation. Le

Calculation of radiative corrections to virtual compton scattering - absolute measurement of the energy of Jefferson Lab. electron beam (hall A) by a magnetic method: arc project

International Nuclear Information System (INIS)

Marchand, D.

1998-11-01

This thesis presents the radiative corrections to the virtual compton scattering and the magnetic method adopted in the Hall A at Jefferson Laboratory, to measure the electrons beam energy with an accuracy of 10 4 . The virtual compton scattering experiments allow the access to the generalised polarizabilities of the protons. The extraction of these polarizabilities is obtained by the experimental and theoretical cross sections comparison. That's why the systematic errors and the radiative effects of the experiments have to be controlled very seriously. In this scope, a whole calculation of the internal radiative corrections has been realised in the framework of the quantum electrodynamic. The method of the dimensional regularisation has been used to the treatment of the ultraviolet and infra-red divergences. The absolute measure method of the energy, takes into account the magnetic deviation, made up of eight identical dipoles. The energy is determined from the deviation angle calculation of the beam and the measure of the magnetic field integral along the deviation

Efficacité relative des grilles de correction d'un test de jugement situationnel pour la sélection du personnel de centres d'appels

OpenAIRE

Poirier, Sabrina

2016-01-01

Dans le domaine des centres d’appels, l’affectation d’agents au service à la clientèle efficaces et satisfaits représente une activité cruciale pour toute direction dédiée aux ressources humaines de ces unités d’affaires. Or, pour parvenir à prendre de bonnes décisions d’embauche et de rejet, des instruments de mesure et d’évaluation des compétences sont souvent mis à contribution. À cet effet, les tests de jugement situationnel (TJS) sont de plus en plus utilisés pour la sélection du personn...

Electroweak radiative corrections to Higgs production via vector boson fusion using soft-collinear effective theory

International Nuclear Information System (INIS)

Fuhrer, Andreas; Manohar, Aneesh V.; Waalewijn, Wouter J.

2011-01-01

Soft-collinear effective theory (SCET) is applied to compute electroweak radiative corrections to Higgs production via gauge boson fusion, qq→qqH. There are several novel features which make this process an interesting application of SCET: The amplitude is proportional to the Higgs vacuum expectation value, and so is not a gauge singlet amplitude. Standard resummation methods require a gauge singlet operator and do not apply here. The SCET analysis requires operators with both collinear and soft external fields, with the Higgs vacuum expectation value being described by an external soft φ field. There is a scalar soft-collinear transition operator in the SCET Lagrangian which contributes to the scattering amplitude, and is derived here.

Performances de ponte et qualité des oeufs des poules pondeuses ...

African Journals Online (AJOL)

Les performances de ponte et la qualité des oeufs de 216 poules pondeuses ISA Brown âgées de 21 semaines ont été déterminées en les alimentant avec des rations contenant des feuilles séchées de manioc (Manihot esculenta, Crantz). Pendant douze semaines, trois groupes de 72 poules chacun (réparties en trois ...

Freins et leviers à la diversification des cultures : étude au niveau des exploitations agricoles et des filières

Directory of Open Access Journals (Sweden)

Meynard Jean-Marc

2013-07-01

Full Text Available La diversification des cultures est souvent présentée comme un levier d’action pour accroître la durabilité des systèmes de production agricoles. Bien raisonnée, elle favorise en effet une réduction de l’usage d’intrants extérieurs à l’exploitation – pesticides, engrais, eau – et des nuisances environnementales associées à leur utilisation excessive. À l’inverse, la simplification des systèmes de culture engagée depuis plus de 40 ans s’est accompagnée d’un recours croissant aux intrants. Cependant, malgré son intérêt pour les systèmes de production en termes de durabilité écologique mais aussi économique (répartition des risques, et son inscription dans divers plans et dispositifs incitatifs, la diversification des cultures progresse peu. Les ministères en charge de l’agriculture et de l’environnement ont donc commandé à l’INRA une étude visant à identifier les freins à la diversification des cultures en France et les leviers mobilisables, par les pouvoirs publics notamment, pour la favoriser. L’hypothèse de travail est que ces freins relèvent du fonctionnement global du système agro-industriel, et de la capacité de développement de filières valorisant les cultures de diversification. L’étude a examiné un certain nombre de cas représentatifs de la diversité des filières et notamment de leurs modes d’organisation, qui déterminent la coordination et l’engagement des acteurs économiques impliqués dans le développement d’une culture de diversification.

Atmospheric correction of APEX hyperspectral data

Directory of Open Access Journals (Sweden)

Sterckx Sindy

2016-03-01

Full Text Available Atmospheric correction plays a crucial role among the processing steps applied to remotely sensed hyperspectral data. Atmospheric correction comprises a group of procedures needed to remove atmospheric effects from observed spectra, i.e. the transformation from at-sensor radiances to at-surface radiances or reflectances. In this paper we present the different steps in the atmospheric correction process for APEX hyperspectral data as applied by the Central Data Processing Center (CDPC at the Flemish Institute for Technological Research (VITO, Mol, Belgium. The MODerate resolution atmospheric TRANsmission program (MODTRAN is used to determine the source of radiation and for applying the actual atmospheric correction. As part of the overall correction process, supporting algorithms are provided in order to derive MODTRAN configuration parameters and to account for specific effects, e.g. correction for adjacency effects, haze and shadow correction, and topographic BRDF correction. The methods and theory underlying these corrections and an example of an application are presented.

Impact écotoxicologique de mélanges de pesticides sur des fonctions microbiennes des sols : apport d’une prise en compte écologique dans l’évaluation des risques

OpenAIRE

Devers-Lamrani, Marion; Rouard, Nadine; Cheviron, Nathalie; Grondin, Virginie; Martin-Laurent, Fabrice

2015-01-01

L’utilisation de pesticides permet d’assurer la qualité de la production végétale mais elle contribue à la contamination des sols et des eaux et produit des effets sur des organismes noncibles. L’évaluation des risques requièrent actuellement une meilleure prise en compte des effets des pesticides sur le fonctionnement des écosystèmes. Or, les démarches et indicateurs classiques manquent de représentativité écologique. La fonction microbienne de biodégradation des pesticides est essentielle c...

Mesure de la masse volumique des particules des eaux résiduaires urbaines : protocole et évaluation des incertitudes

OpenAIRE

RUBAN, Gwenaël; LABORATOIRE CENTRAL DES PONTS ET CHAUSSEES - LCPC

2004-01-01

La connaissance de la masse volumique des particules des eaux résiduaires urbaines est intéressante notamment pour l'étude de leur traitement par décantation ainsi que des relations entre concentrations en matières en suspension et paramètres optiques (turbidimétrie).Une étude des différentes méthodes de mesure de la masse volumique appliquées aux eaux résiduaires a été effectuée par G. Chebbo (1992). Il en a conclu que le pycnomètre à gaz type Beckman est le seul appareil donnant satisfactio...

Problèmes entomologiques en replantation des palmeraies et des cocoteraies

Directory of Open Access Journals (Sweden)

Mariau Dominique

2000-03-01

Full Text Available C’est aux alentours de la vingt-cinquième année que l’on envisage de replanter une palmeraie. C’est en effet vers cet âge que commencent à se poser des problèmes de récolte en raison de la taille des palmiers. En un quart de siècle, l’amélioration génétique aura suffisamment fait de progrès pour escompter un gain de production de l’ordre de 20%. Enfin, dans certaines situations, plusieurs maladies ont pu affecter les vieilles palmeraies. Avec de 15 à 25% d’arbres manquants, principalement lorsque ceux-ci se présentent sous la forme de taches, une diminution de la production se fait nettement sentir. Cela peut, par exemple, être le cas avec les maladies de la fusariose en Afrique de l’Ouest, lorsque la palmeraie n’a pas été plantée avec du matériel végétal tolérant, ou du ganoderma en Malaisie. Le renouvellement des cocoteraies se fait avec un espace de temps beaucoup plus long. En effet, la récolte des noix peut se faire au sol et la hauteur des cocotiers n’est donc pas un facteur limitant. Par ailleurs, la majorité des cocoteraies étant sous la forme de petites plantations villageoises, les agriculteurs rechignent toujours à abattre leurs cocotiers, même si des semences potentiellement plus productives leurs sont proposées. Ce sont les raisons pour lesquelles les cocoteraies de 50 ans et plus représentent la règle. L’abattage d’une plantation de palmiers à huile ou de cocotiers constitue naturellement un changement brutal de l’environnement, ce qui a des conséquences importantes notamment sur l’entomofaune, parmi laquelle des ravageurs majeurs ainsi que leurs ennemis naturels.

Radiative corrections due to a heavy Higgs-particle

International Nuclear Information System (INIS)

Van der Bij, J.J.

1984-01-01

The leading two-loop corrections to the rho parameter and to the vectorboson masses was calculated in the limit of large Higgs-mass. The corrections appear to be too small to be measured, of the order of a few tenths of a percent. For rho perturbation theory breaks down for a Higgs-mass of 11 TeV and larger, for the vectorboson mass this happens for a Higgs-mass of a 4 TeV or larger. There is no direct correspondence between these results and the poles at n=3 in the gauged non-linear σ-model

Innovation pour la santé des mères et des enfants d'Afrique

International Development Research Centre (IDRC) Digital Library (Canada)

Corey Piccioni

... détermineront les interventions devant absolument faire partie de la formation des travailleurs de santé communautaire. Cela pourrait comprendre des régimes de vitamines prénatals et des billets de transport à des établissements de santé pour le dépistage de troubles d'hypertension ou d'infection au VIH, entre autres.

Isolement et identification des levures.

Directory of Open Access Journals (Sweden)

S. DOMERCQ

1967-06-01

Full Text Available La fermentation du moût de raisin est assurée par les levures qui se trouvent sur la pellicule du raisin, sur les rafles, et aussi, par celles qui envahissent le matériel de vendange et de vinification dès que la récolte est commencée. L'apparition deLa fermentation du moût de raisin est assurée par les levures qui se trouvent sur la pellicule du raisin, sur les rafles, et aussi, par celles qui envahissent le matériel de vendange et de vinification dès que la récolte est commencée. L'apparition des signes de la fermentation est spontanée. La fermentation est rapide dans la majorité des cas, si elle devient trop violente et que la température s'élève dangeureusement, il faut la « canaliser », la calmer. Des accidents peuvent se produire; des arrêts de fermentation laissant des sucres non fermentés pouvant être attaqués par d'autres microorganismes, des développements de levures formant des substances nuisibles à la qualité; par la suite, il s'agit d'obtenir la stabilité du vin, en particulier, éviter les refermentations des vins doux. L'étude de ces problèmes nécessite une étude préliminaire, celle des levures responsables de la fermentation alcoolique du jus de raisin, qui ne peut être faite que sur des cultures pures, isolées au préalable à l'aide de prélèvements soigneusement réalisés.s signes de la fermentation est spontanée. La fermentation est rapide dans la majorité des cas, si elle devient trop violente et que la température s'élève dangeureusement, il faut la « canaliser », la calmer. Des accidents peuvent se produire; des arrêts de fermentation laissant des sucres non fermentés pouvant être attaqués par d'autres microorganismes, des développements de levures formant des substances nuisibles à la qualité; par la suite, il s'agit d'obtenir la stabilité du vin, en particulier, éviter les refermentations des vins doux. L'étude de ces problèmes nécessite une étude pr

Innovation pour la santé des mères et des enfants d'Afrique | CRDI ...

International Development Research Centre (IDRC) Digital Library (Canada)

L'initiative Innovation pour la santé des mères et des enfants d'Afrique (ISMEA) cherche à améliorer la santé des mères, des nouveau-nés et des enfants en ... Cette initiative de 36 millions de dollars sur sept ans – financée conjointement par les Instituts de recherche en santé du Canada, Affaires mondiales Canada et le ...

Addendum to ''Radiative corrections to the Dalitz plot of semileptonic decays of neutral baryons with light or charm quarks''

International Nuclear Information System (INIS)

Martinez, A.; Tun, D.M.; Garcia, A.; Sanchez-Colon, G.

1994-01-01

We show that the radiative corrections containing terms up to order αq/πM 1 for unpolarized semileptonic decays of baryons with positron emission can be obtained by simply reversing the sign of the axial-vector form factors in the corresponding final expressions of such decays with electron emission. This rule is valid regardless of the final kinematical variables chosen and of the particular Lorentz frame in which the final results are required

Effect of Inhomogeneity correction for lung volume model in TPS

International Nuclear Information System (INIS)

Chung, Se Young; Lee, Sang Rok; Kim, Young Bum; Kwon, Young Ho

2004-01-01

The phantom that includes high density materials such as steel was custom-made to fix lung and bone in order to evaluation inhomogeneity correction at the time of conducting radiation therapy to treat lung cancer. Using this, values resulting from the inhomogeneous correction algorithm are compared on the 2 and 3 dimensional radiation therapy planning systems. Moreover, change in dose calculation was evaluated according to inhomogeneous by comparing with the actual measurement. As for the image acquisition, inhomogeneous correction phantom(Pig's vertebra, steel(8.21 g/cm 3 ), cork(0.23 g/cm 3 )) that was custom-made and the CT(Volume zoom, Siemens, Germany) were used. As for the radiation therapy planning system, Marks Plan(2D) and XiO(CMS, USA, 3D) were used. To compare with the measurement value, linear accelerator(CL/1800, Varian, USA) and ion chamber were used. Image, obtained from the CT was used to obtain point dose and dose distribution from the region of interest (ROI) while on the radiation therapy planning device. After measurement was conducted under the same conditions, value on the treatment planning device and measured value were subjected to comparison and analysis. And difference between the resulting for the evaluation on the use (or non-use) of inhomogeneity correction algorithm, and diverse inhomogeneity correction algorithm that is included in the radiation therapy planning device was compared as well. As result of comparing the results of measurement value on the region of interest within the inhomogeneity correction phantom and the value that resulted from the homogeneous and inhomogeneous correction, gained from the therapy planning device, margin of error of the measurement value and inhomogeneous correction value at the location 1 of the lung showed 0.8% on 2D and 0.5% on 3D. Margin of error of the measurement value and inhomogeneous correction value at the location 1 of the steel showed 12% on 2D and 5% on 3D, however, it is possible to

Analyse des caractéristiques structurelles et des performances ...

African Journals Online (AJOL)

SARAH

28 févr. 2014 ... performances technico-économiques de la riziculture irriguée en Côte d' .... en nous basant sur les prix des intrants et des produits en vigueur au cours ..... la recherche et de la vulgarisation et le transfert de technologies ; (2) ...

Enquête de satisfaction des restaurants

CERN Multimedia

Staff Association

2016-01-01

Comité de surveillance des restaurants L’Association du personnel est représentée dans plusieurs comités dont le Comité de surveillance des restaurants (CSR) qui a pour mandat : de donner son avis sur toute question relative à la politique générale de l’Organisation en matière de restauration sur le site, y compris en ce qui concerne les termes et l’attribution des contrats d’exploitation des restaurants ; de définir dans le cadre des contrats d’exploitation des restaurants, les prestations correspondant aux besoins et, dans la mesure du possible, aux désirs du personnel ; de surveiller les prestations des restaurants, y compris en ce qui concerne la qualité et la préparation des produits ; de négocier avec les concessionnaires des restaurants au sujet des tarifs et de surveill...

Contraintes d'adoption des technologies de gestion de la fertilite des ...

African Journals Online (AJOL)

La baisse de fertilité des sols, l'une des principales contraintes du secteur agricole au Togo, sévit encore plus dans la riziculture irriguée où les terres sont exploitées chaque année sans jachère. Face à cette situation, diverses solutions comme les technologies de gestion de la fertilité des sols ont été proposées.

contraintes d'adoption des technologies de gestion de la fertilite des ...

African Journals Online (AJOL)

La baisse de fertilité des sols, l'une des principales contraintes du secteur agricole au Togo, sévit encore plus dans la riziculture irriguée où les terres sont exploitées chaque année sans jachère. Face à cette situation, diverses solutions comme les technologies de gestion de la fertilité des sols ont été proposées.

Droit des organisations internationales

CERN Document Server

Sorel, Jean-Marc; Ndior, Valère

2013-01-01

Cet ouvrage collectif offre aux enseignants et chercheurs en droit international, aux praticiens et aux étudiants, une analyse actualisée du droit des organisations internationales. Il dresse en cinq parties un tableau, illustré par des exemples variés, des problématiques que soulève le phénomène polymorphe d institutionnalisation de la société internationale. La première partie est consacrée au phénomène des « organisations internationales », sous l angle à la fois de l institutionnalisation progressive des relations internationales et de la difficulté à cerner une catégorie unifiée. La deuxième partie rend compte de la création, de la disparition et des mutations des organisations internationales, ici envisagées comme systèmes institutionnels et ordres juridiques dérivés. La troisième partie analyse l autonomie que l acquisition de la personnalité juridique et de privilèges et immunités, un organe administratif intégré, un personnel ou un budget propres confèrent aux organi...

De la problématique des articles synopsis dans la compilation des ...

African Journals Online (AJOL)

Autrement dit, au Gabon l'attention doit porter sur l'utilisation des articles synopsis dans la compilation des dictionnaires, en vue de refléter dans ses ouvrages la diversité linguistique et culturelle de ce pays. Ceci est d'autant plus vrai que l'utilisation des articles synopsis ne dépend aucunement de la typologie du ...

L’impact des biocarburants sur l’effet de serre

Directory of Open Access Journals (Sweden)

Poitrat Etienne

2002-09-01

Full Text Available Selon les statistiques de l’Observatoire de l’Énergie [1], la France a consommé 267 Mtep (tonnes équivalent pétrole d’énergie primaire en 2001, ou 269 Mtep avec correction climatique. Cette consommation comprend 145,6 Mtep sous forme d’énergie fossile (tableau 1. Les émissions corrigées du seul CO2 correspondant à l’énergie primaire consommée ont été entre août 2001 et juillet 2002, de 109 Mt de carbone par an [2]. Les énergies renouvelables (EnR totales utilisées en France sont d’environ 28 Mtep/an, dont 16,1 tep sont produits par les grands barrages hydro-électriques. Les autres EnR sont les bioénergies (11,9 Mtep/an et les énergies restantes, sont la géothermie, le solaire, l’éolien et la petite hydraulique [3]. En Europe, la France occupe la 5e place avec 11,5 % d’énergie renouvelable consommée après la Suède (26,7 %, l’Autriche (23,3 %, la Finlande (20,9 % et le Portugal (16,9 % [4]. D’autre part, la réserve mondiale prouvée des énergies fossiles représente au rythme actuel de consommation, qui est de 77 % de l’énergie totale consommée (tableau 2, environ 45 ans pour le pétrole, 60 ans pour le gaz et 220 à 250 ans pour le charbon. Afin de réduire les émissions de carbone fossile issues de la combustion des 77 % des énergies fossiles utilisées, il est nécessaire de réduire les consommations d’énergie par des économies et l’amélioration des rendements, de développer les énergies renouvelables et les technologies de séquestration du carbone. En France, les transports dépendent à plus de 95 % des hydrocarbures, non renouvelables, dont l’utilisation a une part déterminante (24 % dans l’émission des gaz à effet de serre. Le transport routier représente 81 % de la consommation énergétique du secteur. L’effet de serre se manifeste par un réchauffement de la température de l’air (+ 0,5 °C/100 ans et des océans (+ 0,3 °C/30 ans, avec une augmentation de la

Evaluation des pratiques de gestion des adventices en riziculture

African Journals Online (AJOL)

Les résultats ont montré que les méthodes de gestion de l'enherbement ont .... Le contrôle des adventices en riziculture irriguée a principalement .... mesurer la hauteur des plantes et la longueur ..... Performance agronomique du Sys- tème de ...

The determination of beam quality correction factors: Monte Carlo simulations and measurements.

Science.gov (United States)

González-Castaño, D M; Hartmann, G H; Sánchez-Doblado, F; Gómez, F; Kapsch, R-P; Pena, J; Capote, R

2009-08-07

Modern dosimetry protocols are based on the use of ionization chambers provided with a calibration factor in terms of absorbed dose to water. The basic formula to determine the absorbed dose at a user's beam contains the well-known beam quality correction factor that is required whenever the quality of radiation used at calibration differs from that of the user's radiation. The dosimetry protocols describe the whole ionization chamber calibration procedure and include tabulated beam quality correction factors which refer to 60Co gamma radiation used as calibration quality. They have been calculated for a series of ionization chambers and radiation qualities based on formulae, which are also described in the protocols. In the case of high-energy photon beams, the relative standard uncertainty of the beam quality correction factor is estimated to amount to 1%. In the present work, two alternative methods to determine beam quality correction factors are prescribed-Monte Carlo simulation using the EGSnrc system and an experimental method based on a comparison with a reference chamber. Both Monte Carlo calculations and ratio measurements were carried out for nine chambers at several radiation beams. Four chamber types are not included in the current dosimetry protocols. Beam quality corrections for the reference chamber at two beam qualities were also measured using a calorimeter at a PTB Primary Standards Dosimetry Laboratory. Good agreement between the Monte Carlo calculated (1% uncertainty) and measured (0.5% uncertainty) beam quality correction factors was obtained. Based on these results we propose that beam quality correction factors can be generated both by measurements and by the Monte Carlo simulations with an uncertainty at least comparable to that given in current dosimetry protocols.

SU-F-J-219: Predicting Ventilation Change Due to Radiation Therapy: Dependency On Pre-RT Ventilation and Effort Correction

Energy Technology Data Exchange (ETDEWEB)

Patton, T; Du, K; Bayouth, J [University of Wisconsin, Madison, WI (United States); Christensen, G; Reinhardt, J [University of Iowa, Iowa City, IA (United States)

2016-06-15

Purpose: Ventilation change caused by radiation therapy (RT) can be predicted using four-dimensional computed tomography (4DCT) and image registration. This study tested the dependency of predicted post-RT ventilation on effort correction and pre-RT lung function. Methods: Pre-RT and 3 month post-RT 4DCT images were obtained for 13 patients. The 4DCT images were used to create ventilation maps using a deformable image registration based Jacobian expansion calculation. The post-RT ventilation maps were predicted in four different ways using the dose delivered, pre-RT ventilation, and effort correction. The pre-RT ventilation and effort correction were toggled to determine dependency. The four different predicted ventilation maps were compared to the post-RT ventilation map calculated from image registration to establish the best prediction method. Gamma pass rates were used to compare the different maps with the criteria of 2mm distance-to-agreement and 6% ventilation difference. Paired t-tests of gamma pass rates were used to determine significant differences between the maps. Additional gamma pass rates were calculated using only voxels receiving over 20 Gy. Results: The predicted post-RT ventilation maps were in agreement with the actual post-RT maps in the following percentage of voxels averaged over all subjects: 71% with pre-RT ventilation and effort correction, 69% with no pre-RT ventilation and effort correction, 60% with pre-RT ventilation and no effort correction, and 58% with no pre-RT ventilation and no effort correction. When analyzing only voxels receiving over 20 Gy, the gamma pass rates were respectively 74%, 69%, 65%, and 55%. The prediction including both pre- RT ventilation and effort correction was the only prediction with significant improvement over using no prediction (p<0.02). Conclusion: Post-RT ventilation is best predicted using both pre-RT ventilation and effort correction. This is the only prediction that provided a significant

Electroweak corrections to H->ZZ/WW->4 leptons

International Nuclear Information System (INIS)

Bredenstein, A.; Denner, A.; Dittmaier, S.; Weber, M.M.

2006-01-01

We provide predictions for the decays H->ZZ->4-bar and H->WW->4-bar including the complete electroweak O(α) corrections and improvements by higher-order final-state radiation and two-loop corrections proportional to G μ 2 M H 4 . The gauge-boson resonances are described in the complex-mass scheme. We find corrections at the level of 1-8% for the partial widths

Technical Developments in the USAEC Process Radiation Development Program; Etudes technologiques dans le cadre du programme de mise au point d'applications industrielles des rayonnements de la CEA-EU; Issledovaniya v oblasti promyshlennogo primeneniya izluchenij, vkhodyashchie v programmu komissii po atomnoj ehnergii USAEC; Progresos tecnicos en el programa de la USAEC para el fomento de la irradiacion industrial

Energy Technology Data Exchange (ETDEWEB)

Machurek, J. E.; Stein, M. H. [Division of Isotopes Development, USAEC, Washington, DC (United States)

1963-11-15

A broad range of researches have been undertaken in the USAEC 'Process radiation development program'. The primary objective of these studies is to foster development of technology leading to the productive industrial use of ionizing radiation. Results of fourteen of these investigations are reported.some in outline in this paper and some in detail in these Proceedings. The subjects included are researches on: (1) Preparation of wood-plastic combinations using gamma radiation to induce polymerization. (2) Use of fission-product beta radiation for the hydrogenation of coal and coal products to produce liquid hydrocarbon fuels. (3) Production of semi-conductor devices with the formation of predetermined spacial distribution impurity patterns via neutron transmutation doping. (4) Radiation-induced polymerization of ethylene and copolymers. (5) Basic studies in radiation-induced reaction mechanisms and kinetics. (6) Radiation chemistry involved in the fluorination of various aromatic compounds. (7) Use of polyfunctional monomers for enhanced radiation cross-linking of polyethylene, polypropylene, polyisobutylene and cellulose acetate. (8) Effect of swelling, strain and temperature on the physical and chemical properties of radiation produced polymers. (9) Radiation-induced changes in polymers leading to graft copolymerization as influenced by structural factors. (10) The utilization of nuclear radiation for the modification of textile materials. (11) Radiation-induced reactions utilizing krypton-85. (12) The preparation of a ''Radiation Handbook''. (13) Use of the organometallic bond in high level gamma radiation dosimetry. (14) The development of a solar cell dosimeter. (author) [French] Des recherches tres diverses ont ete entreprises dans le cadre du programme de mise au point d'applications industrielles des rayonnements execute par la CEA-EU. Ce programme a pour but essentiel de favoriser le developpement de la technologie en vue d'un emploi industriel productif

Performances des équipements utilisés en liaison froide en liaison froide en restauration hospitalière - Suivi des températures des entrées froides

OpenAIRE

Rosset , Philippe; Morelli , Elisabeth; Noël , Véronique; Poumeyrol , Gérard

2007-01-01

La restauration hospitalière présente un système de distribution des repas qui lui est spécifique : assemblage des denrées préparées et constitution des plateaux-repas dans un local dédié (dit d'allotissement) ; transport des plateaux-repas vers les unités de soins dans des enceintes mobiles permettant le maintien au froid des denrées consommées froides et la remise en température des aliments à consommer chauds. La présente étude concerne le suivi des températures de hors-d'œuvre dans trois ...

Count rate balance method of measuring sediment transport of sand beds by radioactive tracers; Methode du bilan des taux de comptage d'indicateurs radioactifs pour la determination du debit de charriage des lits sableux

Energy Technology Data Exchange (ETDEWEB)

Sauzay, G [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

1967-11-01

Radioactive tracers are applied to the direct measurement of the sediment transport rate of sand beds. The theoretical measurement formula is derived: the variation of the count rate balance is inverse of that of the transport thickness. Simultaneously the representativeness of the tracer is critically studied. The minimum quantity of tracer which has to be injected in order to obtain a correct statistical definition of count rate given by a low number of grains 'seen' by the detector is then studied. A field experiment was made and has let to study the technological conditions for applying this method: only the treatment of results is new, the experiment itself is carried out with conventional techniques applied with great care. (author) [French] Les indicateurs radioactifs sont appliques a la mesure directe du debit de charriage des lits sableux. On etablit la formule theorique de mesure: le bilan des taux de comptage varie en sens inverse de l'epaisseur de charriage. Parallelement on fait une etude critique de la representativite de l'indicateur, puis on determine la quantite minimale de traceur qu'il faut immerger pour que les taux de comptage fournis pour un faible nombre de grains 'vus' par le detecteur aient une definition statistique correcte. Une experience de terrain a permis d'etudier les conditions technologiques de cette methode: seul le depouillement des resultats est nouveau. L'experimentation in-situ se fait suivant les procedes classiques avec un tres grand soin. (auteur)

Reconnaissance de caractères : évaluation des performances

OpenAIRE

Belaïd , Abdel; Cecotti , Hubert

2006-01-01

National audience; La numérisation de documents est une étape importante dans la mise en place d'un système de gestion électronique de documents (GED). Le choix de la solution de numérisation doit prendre en compte toutes les étapes de traitement des documents depuis l'acquisition, la conversion du contenu (texte et structure) jusqu'à la correction et la mise en exploitation du document final. Le but de cette numérisation est une utilisation du contenu converti, par exemple pour effectuer une...

Vers une meilleure comprehension des savoirs disciplinaires et curriculaires des enseignants ou Ie paradigme retrouve

Directory of Open Access Journals (Sweden)

Stephane Martineau

1999-01-01

Full Text Available eet article se veut essentieUement un travail de synthese sous la forme d 'une breve revue de litterature au sujet des savoirs disciplinaires et curriculaires en enseignement. Plus specifiquement, il vise a determiner queUes sont les principales conclusions qui se degagent de la lecture des recherches empiriques sur les savoirs disciplinaires et curriculaires des enseignants des ordres d'enseignement primaire et secondaire. Il propose donc une classification des differentes dimensions constitutives du rapport entre les savoirs disciplinaires et curriculaires et la pratique enseignante. Les resultats mis au jour permettent d 'une part, d'identifier les facteurs qui entrainent des differences dans les connaissances disciplinaires et curriculaires des enseignants et d'autre part, de mieux saisir comment ces connaissances de l'enseignant peuvent influencer en retour sa pratique.

Contrôle hormonal des caractéristiques des fibres musculaires après la naissance

OpenAIRE

Cassar-Malek, Isabelle; Listrat, Anne; Picard, Brigitte

1998-01-01

Après la naissance, la croissance et les propriétés contractiles et métaboliques des fibres musculaires sont soumises à une régulation endocrinienne complexe. A l’exception des glucocorticoïdes, la plupart des hormones présente une action anabolique sur le tissu musculaire. Leur influence sur les caractéristiques des fibres est cependant très différente. Ainsi, les hormones somatotropes affectent peu la composition en fibres des muscles. La GH, comme l’IGF-1, régulerait cependant l’expression...

Modélisation des propriétés diélectriques des nanocomposites ...

African Journals Online (AJOL)

Dans ce travail, nous nous intéressons aux propriétés diélectriques dans le domaine des micro-ondes (2.45, 9.50 et 35 GHz) des composites constitués des inclusions de noir de carbone dans une matrice résine époxyde. Nous avons utilisé deux types de carbone : le monarch 700 et le sterling, dont les diamètres des ...

Civili, langue des Baloango

DEFF Research Database (Denmark)

Mavoungou, Paul Achille; Ndinga-Koumba-Binza, Hugues Steve

, Congo, Angola, etc.) issus de la décolonisation. Il présente de façon succincte quelques phénomènes historiques, phonologiques, morphosyntaxiques, homonymiques et analogiques de la langue. Des faits sémantiques des emprunts linguistiques y sont également décrits dans le cadre des changements...

Evaluation of bias-correction methods for ensemble streamflow volume forecasts

Directory of Open Access Journals (Sweden)

T. Hashino

2007-01-01

Full Text Available Ensemble prediction systems are used operationally to make probabilistic streamflow forecasts for seasonal time scales. However, hydrological models used for ensemble streamflow prediction often have simulation biases that degrade forecast quality and limit the operational usefulness of the forecasts. This study evaluates three bias-correction methods for ensemble streamflow volume forecasts. All three adjust the ensemble traces using a transformation derived with simulated and observed flows from a historical simulation. The quality of probabilistic forecasts issued when using the three bias-correction methods is evaluated using a distributions-oriented verification approach. Comparisons are made of retrospective forecasts of monthly flow volumes for a north-central United States basin (Des Moines River, Iowa, issued sequentially for each month over a 48-year record. The results show that all three bias-correction methods significantly improve forecast quality by eliminating unconditional biases and enhancing the potential skill. Still, subtle differences in the attributes of the bias-corrected forecasts have important implications for their use in operational decision-making. Diagnostic verification distinguishes these attributes in a context meaningful for decision-making, providing criteria to choose among bias-correction methods with comparable skill.

Comment constituer et traiter des corpus issus des médias sociaux à l’aide des CAQDAS? NVivo : un instrument pour l’analyse des discours numériques

Directory of Open Access Journals (Sweden)

Ferrari Giovannipaolo

2015-01-01

Full Text Available Avec l’apparition des médias sociaux, le chercheur en Sciences Humaines et Sociales a vu s’ouvrir des possibilités de création de corpus à partir des données disponibles en ligne. Le risque dans ces modalités de création de corpus est de créer de grandes bases de données difficilement gérables avec les outils traditionnels et surtout dans le cadre d’une recherche qualitative. Pour cette raison, il semble important de mobiliser des outils numériques pour l’aide à la recherche. Ces logiciels sont appelés CAQDAS. Cette contribution montre comment les utiliser pour une enquête de terrain en ligne ou numérique afin d’organiser et d’analyser un corpus. Ce corpus est constitué en vue d’une analyse des discours produits dans le contexte professionnel de la radio utilisant les nouveaux médias.

Ethnobotanique des plantes médicinales anti hémorroïdaires des ...

African Journals Online (AJOL)

SARAH

2015-12-31

Dec 31, 2015 ... but est de valoriser la médecine à base des plantes dans le traitement des pathologies ... médicinales anti hémorroïdaires et le coût réduit des recettes serait pour les populations démunies, ...... l'Afrique, Unesco/Aetfat/Unso.

Theory of the diffusion coefficient of neutrons in a lattice containing cavities; Theorie du coefficient de diffusion des neutrons dans un reseau comportant des cavites

Energy Technology Data Exchange (ETDEWEB)

Benoist, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-01-15

In an previous publication, a simple and general formulation of the diffusion coefficient, which defines the mode of weighting of the mean free paths of the various media, in introducing the collision probabilities in each medium, was established. This expression is demonstrated again here through a more direct method, and the velocity is introduced; new terms are emphasised, the existence of which implies that the representation of the diffusion area as the mean square of the straight line distance from source to absorption is not correct in a lattice. However these terms are of small enough an order of magnitude to he treated as a correction. The general expression also shows the existence, for the radial coefficient, of the series of angular correlation terms, which is seen to converge very slowly for large channels. The term by term computation which was initiated in the first work was then interrupted and a global formulation, which emphasize a resemblance with the problem of the thermal utilisation factor, was adopted. An integral method, analogous to that use for the computation of this factor, gives the possibility to establish new and simple practical formulae, which require the use of a few basic functions only. These formulae are very accurate, as seen from the results of a variational method which was studied as a reference. Various correction effects are reviewed. Expressions which allow the exact treatment of fuel rod clusters are presented. The theory is confronted with various experimental results, and a new method of measuring the radial coefficient is proposed. (author) [French] Dans une publication anterieure, on a etablie une formulation simple et generale du coefficient de diffusion, qui definit le mode de ponderation des libres parcours des differents milieux constituants en faisant apparaitre les probabilites de collision dans chaque milieu. On redemontre ici cette expression d'une maniere plus directe, tout en introduisant la variable

Contribution to the study of the action of electromagnetic fields on the angular correlations of nuclear radiation (1960); Contribution a l'etude de l'action des champs electromagnetiques sur les correlations angulaires des rayonnements nucleaires (1960)

Energy Technology Data Exchange (ETDEWEB)

Lehmann, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-01-15

This work deals with the study of interaction of E.M. fields with nuclear moments of nuclei emitting gamma rays. We describe first experiments on delayed angular correlation showing the role played by statistic quadrupole interaction. We have measured the magnetic moment of the second excited state of {sup 19}F using an external magnetic field. In the case of {sup 19}O, experiments of angular distributions and angular correlations of gamma -rays taking into account the possibility of perturbations, allow us to determine the spin and parities of the three first levels. (author) [French] Le present travail concerne l'etude de l'interaction des champs electromagnetiques et des moments nucleaires de noyaux emettant des rayonnements gamma. Nous decrivons des experiences de correlation angulaire differee dont l'interpretation met en coincidence le role joue par les interactions quadrupolaires statiques. Nous avons mesure le moment magnetique de {sup 19}F dans un etat excite en utilisant un champ magnetique exterieur a la source radioactive. Enfin, dans le cas de {sup 19}O, nous montrons l'utilite d'un examen des possibilites de perturbations dans l'interpretation des resultats fournis par des correlations ou des distributions angulaires. (auteur)

Table des illustrations

OpenAIRE

2016-01-01

Tableaux Dates d’inauguration des grands hôtels japonais entre 1860 et 1945… 19 Histoire, tourisme et hôtellerie en Corée depuis les années 1870… 59-60 Dates d’inauguration des grands hôtels chinois depuis 1863… 84 Les hôtels de luxe et leurs capacités d’hébergement en Corée en 2000… 103 Les flux de personnes suscités par les hôtels « super luxe » de Séoul en 2000… 105 L’activité des grands hôtels à Séoul en 1999 (en wons)… 106 Propriété et gestion des grands hôtels à Séoul en 1999…. 110 La c...

La recherche en action : des solutions locales, des effets durables ...

International Development Research Centre (IDRC) Digital Library (Canada)

15 déc. 2010 ... Le Centre de recherches pour le développement international (CRDI) appuie la production et l'application de connaissances qui améliorent de façon notable la situation des habitants des pays en développement.

Accuracy and Radiation Dose of CT-Based Attenuation Correction for Small Animal PET: A Monte Carlo Simulation Study

International Nuclear Information System (INIS)

Yang, Ching-Ching; Chan, Kai-Chieh

2013-06-01

-Small animal PET allows qualitative assessment and quantitative measurement of biochemical processes in vivo, but the accuracy and reproducibility of imaging results can be affected by several parameters. The first aim of this study was to investigate the performance of different CT-based attenuation correction strategies and assess the resulting impact on PET images. The absorbed dose in different tissues caused by scanning procedures was also discussed to minimize biologic damage generated by radiation exposure due to PET/CT scanning. A small animal PET/CT system was modeled based on Monte Carlo simulation to generate imaging results and dose distribution. Three energy mapping methods, including the bilinear scaling method, the dual-energy method and the hybrid method which combines the kVp conversion and the dual-energy method, were investigated comparatively through assessing the accuracy of estimating linear attenuation coefficient at 511 keV and the bias introduced into PET quantification results due to CT-based attenuation correction. Our results showed that the hybrid method outperformed the bilinear scaling method, while the dual-energy method achieved the highest accuracy among the three energy mapping methods. Overall, the accuracy of PET quantification results have similar trend as that for the estimation of linear attenuation coefficients, whereas the differences between the three methods are more obvious in the estimation of linear attenuation coefficients than in the PET quantification results. With regards to radiation exposure from CT, the absorbed dose ranged between 7.29-45.58 mGy for 50-kVp scan and between 6.61-39.28 mGy for 80-kVp scan. For 18 F radioactivity concentration of 1.86x10 5 Bq/ml, the PET absorbed dose was around 24 cGy for tumor with a target-to-background ratio of 8. The radiation levels for CT scans are not lethal to the animal, but concurrent use of PET in longitudinal study can increase the risk of biological effects. The

La revolution des savants

CERN Document Server

Chavanne, A

1989-01-01

Premiere cassette : - 1666 : impact de la creation de l'Academie des Sciences par Colbert, trente ans apres le proces de Galile, et au moment des disparitions de Pascal, Descartes et Fermat. Elle dirigee par le hollandais Huyggens jusqu'a sa fuite de France au moment de la revocation de l'Edit de Nantes. - 1750 : l'Encyclopedie (ou "Dictionnaire raisonne des Sciences, des Arts et des Metiers") de Diderot et d'Alembert, soutenus par Malherbes, Buffon, Condorcet et Rousseau. - 1789 : Revolution francaise. - 8 aout 1793 : l'Assemblee, par une declaration de Marat, dissout l'Academie des Sciences. Celle-ci continue cependant ses travaux pour les poids et mesures jusqu'en 1795. - la Terreur : la condamnation a mort, pas au nom d'une "Revolution qui n'a pas besoin de savants" mais pour d'autres raisons, de trois grands hommes de science : Lavoisier, Bailly et Condorcet. - 1793-1794 : Au printemps 93, le Comite de Salut Publique s'inquiete du demi-million de soldats etrangers de toutes les pays frontaliers qui essai...

Diversification des moyens de subsistance des petits producteurs de ...

International Development Research Centre (IDRC) Digital Library (Canada)

L'économie du Malawi repose essentiellement sur la culture du tabac, qui représente plus de 70 % des revenus d'exportation. Pour 60 % des 100 000 membres de la National Smallholder Farmers' Association of Malawi (NASFAM), le tabac est la seule et unique source de revenus. Les cultivateurs de tabac, au Malawi ...

À l’aube des dieux

Directory of Open Access Journals (Sweden)

Pascal Semonsut

2011-03-01

Full Text Available De l’avis même des préhistoriens, la Préhistoire assiste à la naissance du sentiment religieux. Cette religion des origines, quelle image en ont les Français ? Telle est la question que cet article aborde à partir de l’étude des manuels scolaires et des œuvres de fiction (littérature, cinéma et bande dessinée de la seconde moitié du XXe siècle. Si l’enseignement et la fiction n’accordent pas la même place à ce thème, en revanche tous deux font des préhistoriques des polythéistes adorant le soleil, construisant des mégalithes et prenant le plus grand soin de leurs morts. Ce mélange d’obscurantisme et de vraie spiritualité n’a qu’un but : montrer que notre espèce ne pouvait être que victorieuse dans ce combat qu’est l’humanisation.

La maison des mathématiques

CERN Document Server

Villani, Cédric; Moncorgé, Vincent

2014-01-01

Comment travaillent les mathématiciens ? C'est peut-être en se promenant dans les couloirs de la première des " maisons des mathématiques " de France, l'institut Henri Poincaré, que l'on trouvera quelques réponses. Le mathématicien Cédric Villani et le physicien Jean-Philippe Uzan nous invitent à découvrir cette discipline et ses acteurs. Au fil des pages on suit, à travers de superbes images signées du photographe Vincent Moncorgé, la façon dont se fabrique cette science qui reste souvent mystérieuse. Toutes les dimensions, scientifique, esthétique et poétique, des mathématiques sont convoquées grâce à des regards croisés : la diversité des inspirations des chercheurs, la source de leur créativité, l'imaginaire littéraire et artistique des mathématiques, la drôle de tribu des mathématiciens. Un voyage au cœur de cette " auberge espagnole " des mathématiques, campus " à la française " accueillant des centaines de chercheurs du monde entier, devenu un lieu d'émulation et d'éc...

Application of the correction factor for radiation qualityKq in dosimetry with pencil-type ionization chambers using a Tandem system

International Nuclear Information System (INIS)

Fontes, Ladyjane Pereira; Potiens, Maria da Penha Albuquerque

2017-01-01

The pencil-type ionization chamber widely used in computed tomography (CT) dosimetry, is a measuring instrument that has a cylindrical shape and provides uniform response independent of the angle of incidence of ionizing radiation. Calibration and measurements performed with the pencil-type ionization chamber are done in terms of Kerma product in air-length (P k,l ) and values are given in Gy.cm. To obtain the values of (P k,l ) during clinical measurements, the readings performed with the ionization chamber are multiplied by the calibration coefficient (N k,l ) and the correction factor C for quality (K q ) which are given in Calibration certificates of the chambers. The application of the correction factor for radiation quality K q is done as a function of the effective energy of the beam that is determined by the Half Value layer (HVL) calculation. In order to estimate the HVL values in this work, a Tandem system made up of cylindrical aluminum and PMMA absorber layers was used as a low cost and easy to apply method. From the Tandem curve, it was possible to construct the calibration curve and obtain the appropriate K q to the beam of the computed tomography equipment studied. (author)

Protection of G2 and G3 against CO{sub 2}; La protection contre le CO{sub 2} des ensembles G.2 et G.3

Energy Technology Data Exchange (ETDEWEB)

Chassany, J Ph; Rodier, J [Commissariat a l' Energie Atomique, Service de Protection contre les Radiations, Marcoule (France). Centre d' Etudes Nucleaires

1961-07-01

The presence of 60.000 m{sup 3} of CO{sub 2} at 15 kg/cm{sup 2} pressure has made necessary to set up a detection and protection system on a scale equal to that used for ionising radiations. Instruments to check CO and CO{sub 2} in the atmosphere carry out measurements continuously, alarm systems give warning if the CO{sub 2} content increases, and the working areas may be surveyed by a whole series of portable instruments. The order for evacuation is given by sirens, and respiratory units are placed at strategic points along the exit paths. (author) [French] La presence de 60000 m{sup 3} de CO{sub 2} a 15 kg/cm{sup 2} de pression a exige la mise en place d'un dispositif de detection et de protection aussi important que celui realise pour les radiations ionisantes. Des appareils de controle d'ambiance pour le CO et le CO{sub 2} effectuent des mesures en permanence, des appareils d'alarme donnent l'alerte en cas d'augmentation de la teneur en CO{sub 2} et tout une serie d'appareils portatifs permettant la surveillance des chantiers. L'evacuation est demandee par sirene et des appareils respiratoires autonomes jalonnent les trajets vers les sorties. (auteur)

Comparison of two heterogeneity correction algorithms in pituitary gland treatments with intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Albino, Lucas D.; Santos, Gabriela R.; Ribeiro, Victor A.B.; Rodrigues, Laura N.; Weltman, Eduardo; Braga, Henrique F.

2013-01-01

The dose accuracy calculated by a treatment planning system is directly related to the chosen algorithm. Nowadays, several calculation doses algorithms are commercially available and they differ in calculation time and accuracy, especially when individual tissue densities are taken into account. The aim of this study was to compare two different calculation algorithms from iPlan®, BrainLAB, in the treatment of pituitary gland tumor with intensity-modulated radiation therapy (IMRT). These tumors are located in a region with variable electronic density tissues. The deviations from the plan with no heterogeneity correction were evaluated. To initial validation of the data inserted into the planning system, an IMRT plan was simulated in a anthropomorphic phantom and the dose distribution was measured with a radiochromic film. The gamma analysis was performed in the film, comparing it with dose distributions calculated with X-ray Voxel Monte Carlo (XVMC) algorithm and pencil beam convolution (PBC). Next, 33 patients plans, initially calculated by PBC algorithm, were recalculated with XVMC algorithm. The treatment volumes and organs-at-risk dose-volume histograms were compared. No relevant differences were found in dose-volume histograms between XVMC and PBC. However, differences were obtained when comparing each plan with the plan without heterogeneity correction. (author)

Importance des indices dans la récupération de l’information en mémoire: cas des élèves de 4ème année primaire, suivant le sexe et la classe d’âge

Directory of Open Access Journals (Sweden)

Florence Gheloube Épouse Ndong Obiang

2017-06-01

Full Text Available La présente étude montre l’importance des indices dans la récupération de l’information en mémoire à court terme (MCT, car la mémoire des apprenants est constamment sollicitée lors des apprentissages. La tâche de rappel indicé a été administrée à 111 élèves de 4ème année des écoles primaires de Libreville. Le traitement de données a été effectué à l’aide du logiciel Statistica. L’analyse de variance indique que, quels que soient le sexe et l’âge il n’y a pas de différence. Mais, Alloway (2006 souligne que la MCT verbale évolue avec l’âge. L’analyse de corrélation révèle qu’il y a une corrélation fortement négative lorsqu’on compare les scores obtenus au rappel indicé correct (RICO, à ceux du rappel indicé incorrect (RINONCO et au nombre d’essais (RIESSAIS. Il est donc essentiel que les enseignants et les élèves aient connaissance et appliquent ces données pour permettre d’améliorer les pratiques des enseignants et les performances des élèves.

Comparison of the standards of air kerma of the OMH and the BIPM for 60Co gamma radiation

International Nuclear Information System (INIS)

Allisy-Roberts, P.J.; Kessler, C.; Burns, D.T.; Roger, P.; Machula, G.; Csete, I.; Rabus, H.

2006-09-01

A direct comparison between the standards for air kerma of the Orszagos Meresugyi Hivatal (OMH) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in the 60 Co radiation beams of the BIPM. The result, expressed as a ratio of the OMH and the BIPM standards for air kerma, indicates a relative difference of 10.9 x 10 -3 with a combined standard uncertainty of 2.2 x 10 -3 . This new result agrees at the level of 0.4 x 10 -3 with the earlier direct comparisons performed in 1986 and 1994, as modified in 2001 by the application of wall and axial non-uniformity correction factors, calculated for the OMH standards using the Monte Carlo method. (authors)

Modernisation des marchés agroalimentaires - inclusion des petits ...

International Development Research Centre (IDRC) Digital Library (Canada)

Les marchés agroalimentaires connaissent de rapides changements dans les pays en développement et les pays en transition. Sous l'influence de la libéralisation du commerce et des nouvelles technologies de transformation des aliments et de commerce de détail, les marchés agroalimentaires évoluent vers une plus ...

Culture du bambou : diversification des moyens de subsistance des ...

International Development Research Centre (IDRC) Digital Library (Canada)

Culture du bambou : diversification des moyens de subsistance des petits producteurs de tabac du sud de la province de Nyanza, au Kenya - phase II. Au cours de la première phase du projet (projet no 103765), les chercheurs ont effectué une analyse de marché pour le bambou et les produits du bambou, comparé les ...

Structurations formelle et conceptuelle des articles de dictionnaires : le premier modèle de codification des articles dans l’histoire des dictionnaires Larousse

Directory of Open Access Journals (Sweden)

Corbin Pierre

2014-07-01

Nous nous proposons d’examiner, dans l’histoire des dictionnaires généraux monolingues Larousse des origines à nos jours, une sélection de jalons de l’articulation entre structure conceptuelle et structure formelle des articles. Au regard de l’ampleur des données à couvrir, il ne pourra bien entendu s’agir que d’un survol, mais celui-ci permettra (1 de présenter le premier des trois modèles majeurs de codification des articles dans l’histoire des dictionnaires Larousse, celui qui trouve son origine dans le Nouveau dictionnaire de la langue française de 1856 ou ses éditions révisées, (2 de prendre en compte les dictionnaires proposés par cet éditeur en un siècle et demi qui ont repris le modèle de 1856 ou sa forme révisée, et (3 de présenter contrastivement au premier les deux autres modèles majeurs, qui trouvent leur ancrage chronologique respectivement dans le Grand dictionnaire universel du XIXe siècle de 1866-1876 et le Dictionnaire du français contemporain de 1966.

Physical matrix correction for RFA of mass and special glasses

International Nuclear Information System (INIS)

Medicus, G.; Ritter, R.

1984-01-01

A theoretical matrix correction model with relatively complex mass absorption coefficients is reported, which takes into account the adsorption of the stimulating radiation and the radiation in the specimen to be measured, as well as the geometry of the spectrometer. With the realized concept of an effective primary wave length, good correction results were obtained over large regions of concentrations and elements. The computer program renders possible besides of the usual reference measurement at uniform reference wave length - the reference of several elements in the specimen to one special element of the reference specimen. The correction method was tested with 42 test glasses, which were previously analyzed. (author)

Etude par imagerie radar des pollutions pétrolières

Directory of Open Access Journals (Sweden)

G. Rees

2004-06-01

Full Text Available En Russie, chaque année, les déversements de pétrole représentent un cinquième de la production totale. Les plus importants se produisent dans le domaine périglaciaire où le milieu naturel est d’une extrême fragilité. Les pipelines sont soumis à de rudes conditions notamment à la corrosion et aux processus cryogéniques. Le risque de rupture augmente en conséquence. La surveillance des déversements d’hydrocarbures, contrainte par l’immensité et la fréquente inaccessibilité du réseau de pipelines, peut être réalisée par le recours à la télédétection. L’objectif de ce travail est de fournir, à travers l’exemple de la catastrophe d’Usinsk (Rép. de Komi survenue en 1994, des outils d’analyse des images radar. Outre leur capacité à s’affranchir du couvert nuageux, les capteurs radar apportent des informations complémentaires à celles fournies par des capteurs optiques. L’exploitation thématique de ces images est rendue difficile par un certain nombre de facteurs perturbateurs tels que les caractéristiques propres du capteur, la direction de visée, la topographie et le phénomène de chatoiement (speckle. Le travail présenté montre le rôle prépondérant joué par ces corrections qui permettent de disposer de données quantitatives comparables d’une date à une autre. La méthode mise au point ici pour le suivi temporel de l’épanchement de pétrole d’Usinsk à partir de trois images radar, est discutée notamment dans ses limites et son aspect opérationnel possible.

Concentration control in an isotope separation plant; Regulation des concentrations dans une usine de separation isotopique

Energy Technology Data Exchange (ETDEWEB)

Jacques, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

Concentration control is examined for the case of a gaseous diffusion plant for uranium isotope separation. The effects of various typical perturbations are described and adequate systems of corrective actions are determined according to selected criteria. (author) [French] On considere une installation de separation des isotopes de l'uranium par diffusion gazeuse. On etudie les effets sur les concentrations isotopiques de diverses perturbations type donnees a l'avance et on determine le systeme d'actions correctives qui permet de reduire ces effets d'apres un critere d'efficacite donne. (auteur)

The refractive-index correction in powder diffraction

International Nuclear Information System (INIS)

Hart, M.; Parrish, W.; Bellotto, M.; Lim, G.S.

1988-01-01

Throughout the history of powder diffraction practice there has been uncertainty about whether or not a refractive-index correction should be made to Bragg's law. High-precision Bragg-angle measurements have been performed with synchrotron radiation on SRM-640 silicon powders at glancing angles; it is found that little or no correction is necessary for the usual 2θ angle range. (orig.)

New approach to SU2LxU1 radiative corrections in e+e- annihilation processes near the Z0 resonance

International Nuclear Information System (INIS)

Jadach, S.; Ward, B.F.L.

1988-08-01

We show explicitly how to proceed in the Monte Carlo simulation of SU 2L xU 1 radiative corrections in order to include multiple soft photon emission on an event by event basis. The method is based on the rigorous theory of summing infrared contributions to the respective cross section by Yennie, Frautschi and Suura. Our method is illustrated on the example of initial state bremsstrahlung. (author). 10 refs, 2 figs

Analysis of the Failures and Corrective Actions for the LHC Cryogenics Radiation Tolerant Electronics and its Field Instruments

CERN Document Server

Balle, Ch; Vauthier, N

2014-01-01

The LHC cryogenic system radiation tolerant electronics and their associated field instruments have been in nominal conditions since before the commissioning of the first LHC beams in September 2008. This system is made of about 15’000 field instruments (thermometers, pressure sensors, liquid helium level gauges, electrical heaters and position switches), 7’500 electronic cards and 853 electronic crates. Since mid-2008 a software tool has been deployed, this allows an operator to report a problem and then lists the corrective actions. The tool is a great help in detecting recurrent problems that may be tackled by a hardware or software consolidation. The corrective actions range from simple resets, exchange of defective equipment, repair of electrical connectors, etc. However a recurrent problem that heals by itself is present on some channels. This type of fault is extremely difficult to diagnose and it appears as a temporary opening of an electrical circuit; its duration can range from a few minutes to ...

Etat des lieux de la gestion des insecticides au Togo, Afrique de l ...

African Journals Online (AJOL)

Pour parvenir à une gestion optimale des maladies à transmission vectorielle ou tout au moins la nuisance culicidienne, une surveillance permanente des facteurs de risque devient nécessaire. Le principal facteur de risque est le vecteur qui transmet la maladie, et le contrôle du vecteur passe par des stratégies de lutte qui ...

Des Connaissances Aux Politiques

International Development Research Centre (IDRC) Digital Library (Canada)

Les synergies ont été mises en commun au fur et à mesure des progrès de la recherche. .... Recherche normative (sur le rôle et la performance des institutions .... Système national d'information sur la gestion environnementale connecté à 19 ...... Un fort contrôle centralisé sur l'élaboration des politiques nationales peut ...

Disinfestation of Dried Figs by Gamma Radiation; Desinsectation des figues seches par les rayons gamma; Dezinfestatsiya sushenogo inzhira s pomoshch'yu gamma-izlucheniya'; Desinfestacion de higos secos mediante rayos gamma

Energy Technology Data Exchange (ETDEWEB)

Papadopoulou, C. P. [Department of Biology, Democritus Nuclear Research Centre, Aghia Paraskevi, Attica (Greece)

1963-09-15

Research has been carried on for many years on the disinfestation of stored agricultural products. Recently gamma radiation has been successfully applied in such investigations. Dried figs are among the main export products of Greece. Serious damage is caused by insect attack each year. The research work aimed at: (1) Determining the doses of radiation required to destroy certain species of insects attacking dried figs at their various stages of development, or to destroy their eggs and thus prevent reproduction; and (2) Determining the physical and chemical changes of the texture of dried figs caused by radiation. Studies have been made on the following species: Plodia interpunctella, Ephestia cautella, Carpophilus hemipterous, Oryzaephilus surinamensis and Lasioderma serricorne. The optimum doses required are discussed. At these doses, irradiation damage does not become apparent in the texture of the figs. (author) [French] Des recherches sur la desinsectation des produits agricoles en magasin sont en cours depuis de nombreuses annees. On a recemment utilise avec succes les rayons gamma dans ces etudes. Les insectes font chaque annee de grands ravages dans les figues seches, qui sont l'un des principaux produits d'exportation de la Grece. L'objet des recherches etait le suivant: 1. Determiner les doses de rayonnements necessaires pour detruire certaines especes d'insectes qui, a differents stades de leur developpement, attaquent les figues, ou detruire leurs oeufs et les empecher ainsi de se reproduire; 2. Determiner les modifications physiques et chimiques que les rayonnements produisent dans la texture de la figue seche. Les travaux ont porte sur les especes suivantes: Plodia interpunctella, Ephestia cautella, Carpophilus hemipterous, Oryzaephilus surinamensis et Lasioderma serricorne. Le memoire etudie les dises optimum d'irradiation, qui ne provoquent aucun dommage visible dans la texture de la figue. (author) [Spanish] Des hace muchos anos se estan

Rôle et limites des tiers-lieux dans la fabrique des villes contemporaines

OpenAIRE

Besson, Raphaël

2017-01-01

La notion de tiers-lieux se développe de manière essentiellement empirique. Elle recouvre des réalités multiples, comme des projets de coworking spaces, de living labs et de fab labs. Certains tiers-lieux s’intéressent tout particulièrement à la ville et aux nouvelles conditions de la fabrique urbaine. En s’appuyant sur des méthodes d’innovation ouverte et le potentiel des outils numériques, ces tiers-lieux défendent l’idée d’un urbanisme qui ne soit plus le patrimoine exclusif d’experts, mai...

L'incidence du prix et des stratégies d'emballage des produits du ...

International Development Research Centre (IDRC) Digital Library (Canada)

Des données internationales, en provenance surtout des pays à revenu élevé, ... pour s'attaquer aux stratégies de marketing ciblant des groupes vulnérables dans ... Les conclusions d'un programme financé par le CRDI au premier plan de la ...

Etat des lieux de la reproduction sexuée des ignames africaines ...

African Journals Online (AJOL)

Les ignames sont d'importantes plantes alimentaires à multiplication végétative dont l'amélioration et la création variétale dépendent, comme chez les végétaux, de la maîtrise de la biologie de la reproduction sexuée. L'état des lieux des cultivars florifères des ignames africaines Dioscorea cayenensis – D. rotundata a été ...

La réforme des politiques sociales : Évolution des perspectives du ...

International Development Research Centre (IDRC) Digital Library (Canada)

Le XXe siècle est une époque remarquable sur le plan des progrès matériels et des transformations d'ordre social et politique. Partout dans le monde, les conditions de vie de la population ont profondément changé à bien des égards: le taux de mortalité infantile et l'analphabétisme chez les adultes ont diminué de façon ...

Un modèle cognitif computationnel de représentation de la connaissance au sein des environnements virtuels d’apprentissage

Directory of Open Access Journals (Sweden)

Mehdi Najjar

2005-01-01

Full Text Available Dans le cadre de la représentation des connaissances au sein des environnements virtuels d’apprentissage (EVA et du fait de la nature relationnelle et structurée de ces connaissances, leur exploitation nécessite de faire appel à des processus d’analyse capables de traiter et de manipuler un grand volume de données structurées. Dans ce sens, un modèle de représentation trouve sa pleine utilité pour la recherche et le traitement automatique d’information guidant le raisonnement, le diagnostic et la prédiction d’un système tuteur dont la tâche est de fournir des suggestions, des exemples et des explications bien adaptés à chaque apprenant. Nous présentons dans cet article un modèle pour représenter la connaissance du domaine et celle des usagers utilisant des EVA. Le modèle s’inspire des recherches en intelligence artificielle sur la modélisation computationnelle et des théories de la psychologie cognitive qui expliquent l’activité cognitive humaine en termes de sous-systèmes de la mémoire et de leurs processus. Ces sous-systèmes (implémentés dans un EVA, parce qu’ils sont similaires à ceux utilisés par l’apprenant, facilitent, d’une part, l’identification de la connaissance acquise correcte ou erronée, et suggèrent, d’autre part, la planification d’une séquence d’activités pédagogiques pour améliorer de manière significative le niveau cognitif de cet apprenant.

Recueillir des données probantes à l'échelle des collectivités pour ...

International Development Research Centre (IDRC) Digital Library (Canada)

Ce projet contribue à la collecte, à l'échelle des collectivités, de données probantes sur les souvenirs des victimes de violations des droits de la personne. Il vise aussi à trouver des stratégies de reconstruction post-atrocités dans un cadre local sûr. Enfin, l'équipe a créé un site Web et produit plusieurs publications.

Innova on pour la santé des mères et des enfants d'Afrique

International Development Research Centre (IDRC) Digital Library (Canada)

19 janv. 2018 ... Les conclusions révèlent des similitudes parmi les cas de divers contextes na onaux, fournissant une riche base de preuves afin d'inspirer des ini a ves visant à améliorer l'équité en ma ère de santé. OUVRIR LE PDF | COMMANDER LE LIVRE. Innova on pour la santé des mères et des enfants d'Afrique.

Administration et gestion des contrats XL

CERN Document Server

Senouf, J

2000-01-01

Les grands contrats de travaux génèrent un grand nombre de commandes (OSVC) passées par un grand nombre de responsables techniques. Ils sont généralement basés sur des bordereaux de prix associés à un éventail de conditions économiques adaptées aux besoins complexes et variés des multiples utilisateurs du CERN nécessitant des calculs sophistiqués. L'administration des commandes, le suivi des travaux et de la facturation doivent répondre aux besoins de tous les acteurs. Les responsables techniques doivent jouir de la plus large indépendance administrative dans le respect des règlements CERN et des conditions contractuelles. Le contrôle des métrés et décomptes doit être rigoureux et d'une traçabilité complète. L'utilisation des bases de données Oracle a déjà permis l'intégration des données administratives et techniques. Le Web nous invite à une communication totale et transparente entre les utilisateurs, les services techniques et les contractants. De nouveaux types de contrat so...

Approche historique des classifications en psychiatrie

OpenAIRE

Garrabé , J.

2011-01-01

Resume Des le milieu du xixe siecle s?est posee la question des criteres de classification des maladies. Pour les maladies mentales, diverses classifications ont alors ete proposees par des auteurs francais (Morel) et allemands (Kahlbaum, Kraepelin). A partir de la fin du xixe siecle, le Bureau International de Statistique (Paris) a publie a une Classification Internationale des Maladies, a revision decennale (J. Bertillon). Cette tache a ete poursuivie dans l?entre-deux-guerres pa...

Étude sur la nutrition menée dans des écoles de la Grenade - des ...

International Development Research Centre (IDRC) Digital Library (Canada)

Étude sur la nutrition menée dans des écoles de la Grenade - des données probantes pour éclairer les politiques. Prévention des maladies non transmissibles. (PMNT). PROFIL DE PROJET. Le programme Prévention des maladies non transmissi- bles (PMNT) soutient la production de nouvelles connais- sances en vue ...

Les effets des interfaces sur les proprietes magnetiques et de transport des multicouches nickel/iron et cobalt/silver

Science.gov (United States)

Veres, Teodor

Cette these est consacree a l'etude de l'evolution structurale des proprietes magnetiques et de transport des multicouches Ni/Fe et nanostructures a base de Co et de l'Ag. Dans une premiere partie, essentiellement bibliographique, nous introduisons quelques concepts de base relies aux proprietes magnetiques et de transport des multicouches metalliques. Ensuite, nous presentons une breve description des methodes d'analyse des resultats. La deuxieme partie est consacree a l'etude des proprietes magnetiques et de transport des multicouches ferromagnetiques/ferromagnetiques Ni/Fe. Nous montrerons qu'une interpretation coherente de ces proprietes necessite la prise en consideration des effets des interfaces. Nous nous attacherons a mettre en evidence, a evaluer et a etudier les effets de ces interfaces ainsi que leur evolution, et ce, suite a des traitements thermiques tel que le depot a temperature elevee et l'irradiation ionique. Les analyses correlees de la structure et de la magnetoresistance nous permettront d'emettre des conclusions sur l'influence des couches tampons entre l'interface et le substrat ainsi qu'entre les couches elles-memes sur le comportement magnetique des couches F/F. La troisieme partie est consacree aux systemes a Magneto-Resistance Geante (MRG) a base de Co et Ag. Nous allons etudier l'evolution de la microstructure suite a l'irradiation avec des ions Si+ ayant une energie de 1 MeV, ainsi que les effets de ces changements sur le comportement magnetique. Cette partie debutera par l'analyse des proprietes d'une multicouche hybride, intermediaire entre les multicouches et les materiaux granulaires. Nous analyserons a l'aide des mesures de diffraction, de relaxation superparamagnetique et de magnetoresistance, les evolutions structurales produites par l'irradiation ionique. Nous etablirons des modeles qui nous aideront a interpreter les resultats pour une serie des multicouches qui couvrent un large eventail de differents comportements magnetiques

Les caractéristiques des stomates des feuilles de Ficus benjamina L ...

African Journals Online (AJOL)

SARAH

25 mars 2014 ... gaz d'échappement des véhicules et des cheminés des usines (Barima et al., 2014). En outre, ces .... inférieures de celle-ci ont été nettoyées à l'eau distillée. Une partie de chaque face inférieure de la feuille a ..... réaction de la plante à empêcher l'absorption de polluants tout en optimisant l'absorption de ...

Postoperative MRI of the ankle; Postoperative Magnetresonanztomographie des Sprunggelenks

Energy Technology Data Exchange (ETDEWEB)

Sharabianlou Korth, M.; Fritz, L.B. [Rheinlandaerzte, Willich (Germany)

2017-11-15

Postoperative imaging of the ankle can be challenging, even for the experienced radiologist. Pathological and postoperative changes to the primarily complex anatomy of the ankle with its great variety of bone structures, tendons, ligaments, and soft tissue in a very limited space may cause great difficulty in differentiating underlying pathology from expected postoperative changes and artifacts, especially in magnetic resonance imaging (MRI). Selecting the appropriate radiological modality is key to making the correct diagnosis. Therefore, knowledge of the initial and current symptoms is just as important as familiarity with the most frequently performed operations in the ankle. This article aims to give its reader a summary of the most important and frequently performed operation techniques of the ankle and discusses the expected appearance and possible complications in postoperative imaging. (orig.) [German] Die postoperative radiologische Bildgebung des Sprunggelenks kann auch fuer den erfahrenen Radiologen eine besondere Herausforderung darstellen. Die komplex aufgebaute Anatomie des Sprunggelenks, mit seinen multiplen Gelenkflaechen, Sehnen, Baendern und neurovaskulaeren Strukturen auf engstem Raum, kann durch Operationen signifikant veraendert und insbesondere in der Magnetresonanztomographie (MRT) verfaelscht dargestellt werden. Fuer eine fundierte Befundung und Beurteilung der Operationsergebnisse ist die Kenntnis der praeoperativen Diagnose, Zeitpunkt und Technik der durchgefuehrten Operation(en) sowie der aktuellen klinischen Symptomatik von grosser Bedeutung. Dieser Artikel konzentriert sich auf zu erwartende radiologische Veraenderungen und gibt Tipps zur Befundung der postoperativen MRT des Sprunggelenks bei einer Auswahl relevanter operativer Eingriffe. Zudem wird auf moegliche postoperative Komplikationen und ihre radiologische Darstellung hingewiesen. (orig.)

Inventaire des cavités souterraines abandonnées et cartographie des dangers qui leur sont liés

Directory of Open Access Journals (Sweden)

Claire ARNAL

1994-12-01

Full Text Available Un inventaire national des cavités souterraines abandonnées, des accidents de sol qui leur sont imputables et de leurs conséquences dommageables a été réalisé à l’échelle de 1/1 000 000 en 1993 et 1994 par le BRGM pour le ministère de l’Environnement (Direction de la Prévention des Pollutions et des Risques. Il a conduit à élaborer des documents cartographiques de synthèse et à définir des niveaux de dangers dont la localisation permettra de lancer des études plus détaillées en vue d’assurer la sécurité des personnes et des biens

Radiative nonrecoil nuclear finite size corrections of order $\\alpha(Z \\alpha)^5$ to the Lamb shift in light muonic atoms

OpenAIRE

Faustov, R. N.; Martynenko, A. P.; Martynenko, F. A.; Sorokin, V. V.

2017-01-01

On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα)5 to the Lamb shift in muonic hydrogen and helium. To construct the interaction potential of particles, which gives the necessary contributions to the energy spectrum, we use the method of projection operators to states with a definite spin. Separate analytic expressions for the contributions of the muon self-energy, the muon vertex operator and the amplitude...

Evaluation des pratiques de gestion des adventices en riziculture ...

African Journals Online (AJOL)

Le riz est l'aliment principal pour la quasi-totalité des populations vivant en Côte d'Ivoire. Cependant, les adventices sont considérées comme la contrainte biologique la plus importante faisant obstacle à la production rizicole. L'objectif de cette étude menée en 2015 était d'évaluer différentes techniques de gestion des ...

Cartographie des zones d'intervention des partenaires techniques et ...

African Journals Online (AJOL)

cartographier les zones d'intervention des partenaires techniques et financiers au Bénin. L'approche méthodologique utilisée a consisté à la recherche documentaire, à la collecte de données auprès des partenaires techniques et financiers et à l'analyse de ces données. Les résultats ont permis de constater que cent dix ...

Radiative corrections to double-Dalitz decays revisited

Science.gov (United States)

Kampf, Karol; Novotný, Jiři; Sanchez-Puertas, Pablo

2018-03-01

In this study, we revisit and complete the full next-to-leading order corrections to pseudoscalar double-Dalitz decays within the soft-photon approximation. Comparing to the previous study, we find small differences, which are nevertheless relevant for extracting information about the pseudoscalar transition form factors. Concerning the latter, these processes could offer the opportunity to test them—for the first time—in their double-virtual regime.

Biometrische Untersuchungen des Stylopodiums, Zygopodiums und Metapodiums pleistozäner Ursiden im Hinblick auf die Evolution des Höhlenbären und die Klassifizierung des Fundmaterials Einhornhöhle / Harz

OpenAIRE

Athen, Kerstin Anja

2007-01-01

In der vorliegenden Dissertation "Biometrische Untersuchungen des Stylopodiums, Zygopodiums und Metapodiums pleistozäner Ursiden im Hinblick auf die Evolution des Höhlenbären und die Klassifizierung des Fundmaterials Einhornhöhle / Harz" wurden Daten des oberpliozänen Ursus etruscus, des pleistozänen Ursus deningeri sowie des Ursus spelaeus ausgewertet. Zur Datenerhebung wurden 249 Messgrößen an den Skelettelementen Humerus, Ulna, Radius, Metacarpalia I-V, Femur, Tibia, Fibula und Metatarsali...

GESTION DES RISQUES ET DES INCERTITUDES L'EMERGENCE D'UN CONTRÔLE DE GESTION " PAR EXCEPTION "

OpenAIRE

Wegmann , Grégory

2003-01-01

International audience; Le thème de la gestion des risques a été peu abordé en contrôle de gestion et le fonctionnement des outils traditionnels comme les budgets postulent une maîtrise des risques et des incertitudes. L'émergence de nouvelles approches en contrôle de gestion montre une évolution sur ce point.

Classical Electron Model with QED Corrections

OpenAIRE

Lenk, Ron

2010-01-01

In this article we build a metric for a classical general relativistic electron model with QED corrections. We calculate the stress-energy tensor for the radiative corrections to the Coulomb potential in both the near-field and far-field approximations. We solve the three field equations in both cases by using a perturbative expansion to first order in alpha (the fine-structure constant) while insisting that the usual (+, +, -, -) structure of the stress-energy tensor is maintained. The resul...

Analyse des systèmes de gestion des déchets par l’étude du mécanisme de répartition des déchets

OpenAIRE

Bergeron, Francis

2015-01-01

Le renforcement de l’usage concurrentiel des déchets nous amène à étudier les processus d’approvisionnement des filières de valorisation et d’élimination sous l’angle de la circulation des flux de déchets au sein d’un système de gestion des déchets. L’objectif du présent article de recherche est de concevoir un cadre théorique autour du concept de mécanisme de répartition des déchets qui désigne le processus de distribution des flux de déchets entre les filières d’élimination et de valorisati...

Radiation-Induced Polymerization of Aldehydes and Ketones; Polymerisation radiochimique des aldehydes et des cetones; Radiatsionnaya polimerizatsiya al'degidov i ketonov; Polimerizacion radioinducida de aldehidos y cetonas

Energy Technology Data Exchange (ETDEWEB)

Hayashi, K.; Yamaoka, H.; Fujiwara, K.; Sakamoto, M.; Mori, S.; Natori, T.; Yoshida, H.; Okamura, S. [Japanese Association for Radiation Research on Polymers, Neyagawa Osaka (Japan); Kyoto University, Kyoto (Japan)

1963-11-15

Several kinds of aldehydes and ketones are polymerized by irradiation. Formaldehyde can be polymerized into high molecular weight polyoxymethylene by radiation-induced polymerization in the liquid phase at low temperatures. The polymerization mechanism is considered to be a cationic chain reaction both in the case of bulk and of solution in methylenechloride and toluene, but to be anionic in ethylether. Acetaldehyde and propionaldehyde are recognized as being hardly polymerized in the pure liquid phase, but easily polymerized in the presence of {gamma}-alumina. In the solid state polymerization, crystalline polymers are obtained as the stable- for- heat-treatment form under suitableconditions. Glyoxal can be polymerized into a three-dimensional network polymer. With formaldehyde it can be copolymerized into some cross-linked polyoxymethylene. Acetones such as chloroor bromoacetone and methylethylketone or diacetyl can be polymerized in the solid state into polymers which are unstable. Ketene can be polymerized into a polyester-type polymer with liquid phase polymerization; polyketone is obtained additionally when polymerization is carried out in the solid state. The copolymer with formaldehyde is slightly more stable. Dimethylketene can be easily polymerized both in the liquid and solid states into polyacetal. All these polymerizations are special examples of radiation-induced reactions and the reaction kinetics are interesting. Some details of this are discussed here. (author) [French] Plusieurs sortes d'aldehydes et de cetones se polymerisent sous l'effet des rayons gamma. L'aldehyde formique peut se transformer en polyoxymethylene de poids moleculaire eleve par polymerisation radiochimique en phase liquide a basses temperatures. On pense que la polymerisation est une reaction cationique en chaine lorsqu'il s'agit de masses ou de solutions dans du chlorure de methylene et du toluene, mais une reaction anionique en chaule dans une solution d'ether ethylique. L

Correction factors for clinical dosemeters used in large field dosimetry

International Nuclear Information System (INIS)

Campos, L.L.; Caldas, L.

1989-08-01

The determination of the absorbed dose in high-energy photon and electron beams by the user is carried out as a two-step procedure. First the ionization chamber is calibrated at a reference quality by the user at a standard laboratory, and then the chamber is used to determine the absorbed dose with the user's beam. A number of conversion and correction factors have to be applied. Different sets of factors are needed depending on the physical quantity the calibration refers to, the calibration geometry and the chamber design. Another correction factor to be introduced for the absorbed dose determination in large fields refers to radiation effects on the stem, cable and sometimes connectors. A simple method was developed to be suggested to hospital physicists to be followed during large radiation field dosimetry, in order to evaluate the radiation effects of cables and connectors and to determine correction factors for each system or geometry. (author) [pt

About particular use of ionizing radiations; Des usages particuliers des rayonnements ionisants

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-02-01

Different uses of ionizing radiations are reviewed: tracers techniques, nuclear gauges, dating by carbon 14, silica doping, use of gamma irradiation for the density measurement in civil engineering, use of a electron capture detector to study by gas chromatography chlorinated contaminants in environment, neutron activation as environmental gauge, analysis of lead in paint and pollutants in ground and dusts, help for work of art valuation by x spectrometry. (N.C.)

Analysis of solids by spark-source mass spectrometry; Analyse des solides au spectrometre de masse a etincelles

Energy Technology Data Exchange (ETDEWEB)

Stefani, R; Desjardins, M; Brun, J C; Cornu, A; Bourguillot, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1965-07-01

Spark source mass spectrometer MS7 has been designed to determine traces of impurities in solids without standards. An atlas of 12 000 lines, assembled in the Grenoble laboratory, allows a quick investigation of mass spectra, notwithstanding their complexity due to multiply charged and polyatomic darkening. Photometric measurements increase accuracy calibration curve is known for each photo-plate. Further, reproducibility is better, if random fluctuations of matrix line darkening are corrected. So far, in a concentration range of 0,01 to 1 000 ppm (atomic), reproducibility is approximately 20 per cent, but absolute value of results depends on 'sensitivity coefficients'. (authors) [French] Le spectrometre de masse a etincelles, de type MS7, est destine a l'analyse chimique de traces dans les solides, sans echantillons etalons. L'emploi de catalogues de 12 000 raies, elabores au laboratoire, permet un depouillement rapide des spectres, malgre leur complexite due aux ionisations multiples et aux associations d'atomes. Le niveau d'apparition d'une impurete donne une estimation de sa teneur, mais la valeur du renseignement depend de la preparation des electrodes et de la connaissance plus ou moins approfondie des processus d'ionisation dans l'etincelle et de noircissement des emulsions photographiques. Les mesures photometriques augmentent la precision des resultats, si l'on determine systematiquement la courbe de noircissement de chaque plaque. De meme la reproductibilite est amelioree si l'on tient compte des fluctuations statistiques du noircissement de l'emulsion par les ions de la matrice. Actuellement, les concentrations mesurees dans le domaine de 0,01 a 1000 ppm atomiques sont reproductibles a 20 pour cent pres, mais leur valeur absolue n'est assuree qu'a un coefficient 3 pres. Des etudes sont en cours pour calibrer l'appareil en valeur absolue, par une determination des coefficients de sensibilite a partir d'echantillons etalons. (auteurs)

Questions de mathématiques élémentaires à l'usage des candidats aux écoles du Gouvernement, des aspirants au baccalauréat ès sciences et des élèves des établissements d'enseignement secondaire

CERN Document Server

Vuibert, Henry

1879-01-01

Questions de mathématiques élémentaires à l'usage des candidats aux écoles du Gouvernement, des aspirants au baccalauréat ès sciences et des élèves des établissements d'enseignement secondaire

Contribution à l’identification des déterminants fondamentaux en évaluation des banques

Directory of Open Access Journals (Sweden)

Badr Habba

2016-03-01

Full Text Available Ce papier étudie l’influence des facteurs fondamentaux sur l’évaluation des banques. Dans un premier temps, nous avons sélectionné, sur la base d’une revue de la littérature, les caractéristiques fondamentales susceptibles d’influencer l’évaluation des banques. Ensuite, nous avons estimé un modèle économétrique mettant en relation la valeur des banques et six variables explicatives à l’aide de l’économétrie des données de panel. L’échantillon est constitué d’un panel de 82 banques cotées entre 2005 et 2013. Les résultats obtenus montrent qu’il existe une influence très significative de la qualité du portefeuille bancaire de crédits, du niveau de capitalisation, du niveau de diversification du portefeuille d’activités, de l’efficience et de la taille de la banque sur l’évaluation des firmes bancaires.

Modification of non metallic materials under the influence of the radiation and thermal retrogradation of these modifications; Modification de materiaux non metalliques sous l'influence des rayonnements et retrogradation thermique de ces modifications

Energy Technology Data Exchange (ETDEWEB)

Mayer, G; Perio, P; Gigon, J; Tournarie, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

The action of the radiation on solids constitute an extremely vast domain of study, which the CEA hardly begins. There is not a very long time, indeed, that we have relatively intense fluxes (6.10{sup 12} thermal neutrons by cm{sup 2}.s{sup -} {sup 1} in the center of the reactor core of Saclay). Materials submitted to radiations, were followed by the evolution of a certain number of physical properties. The study of thermal retrogradation, at moderate temperature, of the modifications provoked by the irradiation were also followed. We will limit, in this report, to expose our experiences on graphite and lithium fluoride. (M.B.) [French] L'action des rayonnements sur les solides constitue un domaine extremement vaste dont l'etude, au Commissariat a l'Energie Atomique, commence a peine. Il n'y a pas tres longtemps, en effet, que nous disposons de flux relativement intenses (6.10{sup 12} neutrons thermiques par cm{sup 2}.s{sup -1} au centre de la pile de Saclay). Dans les materiaux soumis au rayonnement nous suivons l'evolution d'un certain nombre de proprietes physiques et nous etudions la retrogradation thermique, a temperature moderee, des modifications provoquees par l'irradiation. Nous nous bornerons ici a exposer nos experiences sur le graphite et le fluorure de lithium. (M.B.)

Measurement units of physical values; Unites de mesure des grandeurs physiques

Energy Technology Data Exchange (ETDEWEB)

Debraine, P [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

1955-07-01

The aim of this paper is twofold: 1) to give an analysis of the formation conditions of the various systems of units, 2) to show how the practical problems involving changes of units can be solved. This analysis leads to the conception of 'types' of systems, which is very useful to clarity the question of rationalized and non rationalized systems. The second point which consists essentially in: 1) finding the relationship between the measures of a given quantity in different systems, 2) deriving practical formulas, 3) deriving formulas in various 'types' of systems, is made easier by use of sets of: * definition formulas, * transformation formulas, * units of the various practical systems with useful numerical information covering the following fields: ** geometry, ** kinematics, ** mechanics, ** electricity and magnetism, ** thermodynamics, ** radiation, ** photometry, These sets being printed on coloured paper can be easily found. A number of numerical examples (21) show in a detailed way how to solve the various problems likely to occur. A chapter is particularly devoted to the Giorgi MKS system. (author) [French] Le but de cet expose est double: 1) donner une analyse des conditions de formation des differents systemes d'unites, 2) montrer comment peuvent se resoudre les problemes pratiques de changement d'unites. Cette analyse amene a 1a conception de ''types'' de systemes, conception tres utile pour eclairer la question des systemes rationalises et non rationalises. La seconde partie du programme qui consiste essentiellement: 1) a determiner les relations entre les mesures d'une meme grandeur dans differents systemes, 2) a etablir des formules pratiques, 3) a etablir les formules valables dans un ''type'' de systeme donne est facilitee par l'utilisation de listes classees de 1) formules de definition, 2) equations de transformation, 3) unites des differents systemes accompagnees de relations numeriques utiles, couvrant les domaines suivants: 1) geometrie, 5

Impacts des caractéristiques physico-chimiques des eaux sur la ...

African Journals Online (AJOL)

Impacts des caractéristiques physico-chimiques des eaux sur la distribution du ... chimiques qui sont à l'origine d'une dégradation croissante de la qualité d'eau. ... Les valeurs d'indice de diversité de Shannon Weaver traduisent une grande ...

ETUDE EXPLORATOIRE DES ACIDES GRAS POLYINSATURÉS DES AIGUILLES DE PIN

OpenAIRE

KADARI, Abdelhamid

2012-01-01

Depuis les temps les plus anciens, l’utilisation des plantes dans le domaine de la santé est toujours d’actualité (1), dans la mesure où elle représente une alternative sérieuse ou tout au moins un complément appréciable à la pharmacie classique issue de la chimie moderne. En effet, plus de 25 % des médicaments prescrits dans le monde entier dérivent directement ou indirectement des plantes (2). Cependant, en tant que sources de médicaments, les plantes restent encore sous plusieurs études, s...

Analyse des mécanismes de transmission des infections sexuellement transmissibles

OpenAIRE

Abraham, Shahnaz

2008-01-01

Ce travail comprend une étude de l'épidémiologie des infections sexuellement transmissibles (IST) et du VIH à Genève et en Suisse. Nous constatons une recrudescence des IST pendant la période analysée 1999-2004, supersosable à la situation observée dans les autres métropoles européennes, tandis que l'incidence du VIH est restée stable. Nous analysons les facteurs importants pour la transmission des IST-VIH et soulignons l'importance de poursuivre les campagnes de prévention, visant non seulem...

Épuration des eaux usées des villes pour soutenir l'agriculture ...

International Development Research Centre (IDRC) Digital Library (Canada)

2 févr. 2011 ... Les eaux usées : manne liquide ? ... Les racines de la plante emprisonnent les matières solides en ... le compostage des déchets ménagers ou l'arrosage des pépinières. ... à la gestion locale de la demande », dans Épuration des eaux usées et l'agriculture urbaine, Editions Enda, Dakar, août 2002. Mbodj ...

Améliorer les conditions de vie des jeunes et des femmes en ...

International Development Research Centre (IDRC) Digital Library (Canada)

Améliorer les conditions de vie des jeunes et des femmes en développant la petite entreprise : mesure de l'impact. Durant les années 2000, la croissance économique et l'augmentation des investissements sociaux ont réduit la pauvreté et offert aux populations de l'Amérique latine de multiples débouchés sur le marché du ...

Gamma camera correction system and method for using the same

International Nuclear Information System (INIS)

Inbar, D.; Gafni, G.; Grimberg, E.; Bialick, K.; Koren, J.

1986-01-01

A gamma camera is described which consists of: (a) a detector head that includes photodetectors for producing output signals in response to radiation stimuli which are emitted by a radiation field and which interact with the detector head and produce an event; (b) signal processing circuitry responsive to the output signals of the photodetectors for producing a sum signal that is a measure of the total energy of the event; (c) an energy discriminator having a relatively wide window for comparison with the sum signal; (d) the signal processing circuitry including coordinate computation circuitry for operating on the output signals, and calculating an X,Y coordinate of an event when the sum signal lies within the window of the energy discriminator; (e) an energy correction table containing spatially dependent energy windows for producing a validation signal if the total energy of an event lies within the window associated with the X,Y coordinates of the event; (f) the signal processing circuitry including a dislocation correction table containing spatially dependent correction factors for converting the X,Y coordinates of an event to relocated coordinates in accordance with correction factors determined by the X,Y coordinates; (g) a digital memory for storing a map of the radiation field; and (h) means for recording an event at its relocated coordinates in the memory if the energy correction table produces a validation signal

Application de la méthode des éléments finis hiérarchiquesà l’analyse thermo- élastique d’unpanneau solaire d’un satellite

OpenAIRE

hamzA-CHERIF, Sidi Mohammed

2013-01-01

Dans l'ère actuelle, Les satellites sont devenus des outils incontournables dans le développement économique (télécommunications, positionnement, prévision météorologique), militaire (renseignement) et scientifique (observation astronomique, microgravité, observation de la Terre, océanographie, altimétrie). Les satellites en orbite sont soumis à des conditions de fonctionnement très sévères, en plus des effets de l’oxygène atomique, le rayonnement ultraviolet, la radiation é...

Theory of the diffusion coefficient of neutrons in a lattice containing cavities; Theorie du coefficient de diffusion des neutrons dans un reseau comportant des cavites

Energy Technology Data Exchange (ETDEWEB)

Benoist, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-01-15

In an previous publication, a simple and general formulation of the diffusion coefficient, which defines the mode of weighting of the mean free paths of the various media, in introducing the collision probabilities in each medium, was established. This expression is demonstrated again here through a more direct method, and the velocity is introduced; new terms are emphasised, the existence of which implies that the representation of the diffusion area as the mean square of the straight line distance from source to absorption is not correct in a lattice. However these terms are of small enough an order of magnitude to he treated as a correction. The general expression also shows the existence, for the radial coefficient, of the series of angular correlation terms, which is seen to converge very slowly for large channels. The term by term computation which was initiated in the first work was then interrupted and a global formulation, which emphasize a resemblance with the problem of the thermal utilisation factor, was adopted. An integral method, analogous to that use for the computation of this factor, gives the possibility to establish new and simple practical formulae, which require the use of a few basic functions only. These formulae are very accurate, as seen from the results of a variational method which was studied as a reference. Various correction effects are reviewed. Expressions which allow the exact treatment of fuel rod clusters are presented. The theory is confronted with various experimental results, and a new method of measuring the radial coefficient is proposed. (author) [French] Dans une publication anterieure, on a etablie une formulation simple et generale du coefficient de diffusion, qui definit le mode de ponderation des libres parcours des differents milieux constituants en faisant apparaitre les probabilites de collision dans chaque milieu. On redemontre ici cette expression d'une maniere plus directe, tout en introduisant la variable

Harmonische Reduktion des linken Ventrikels

OpenAIRE

Atila, M. (Mehmet)

2005-01-01

In der vorliegenden Arbeit wurde die harmonische Reduktion des linken Ventrikels am Modell des ausgewachsenen Hausschweins, unter Verwendung von Saugkappen variabler Größe untersucht. In 10 Schweinen mit Herzen normaler Größe und Funktion wurde eine Saugkappe, in Größe und Form an das abzufaltende Wandsegment angepasst, auf die epikardiale Oberfläche des schlagenden Herzens gesetzt. Wir führten Messungen der linksventrik. und der pulmonalart. Drücke, des ventrikulären Durchmessers und der Her...

Étude des impacts écologiques du dynamisme spatio-temporel des ...