1,714 research outputs found

    Surface properties of nuclear pairing with the Gogny force in a simplified model

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    Surface properties of neutron-neutron (T=1) pairing in semi-infinite nuclear matter in a hard wall potential are investigated in BCS approximation using the Gogny force. Surface enhancement of the gap function, pairing tensor and correlation energy density is put into evidence.Comment: 16 pages; 4 figures ; submitted to Phys. Lett.

    Semi-Classical Description of the Average Pairing Properties in Nuclei

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    We present a new semi-classical theory for describing pairing in finite Fermi systems. It is based in taking the ‚ĄŹ‚Üí0\hbar \to 0, i.e. Thomas-Fermi, limit of the gap equation written in the basis of the mean field (weak coupling). In addition to the position dependence of the Fermi momentum, the size dependence of the matrix elements of the pairing force is also taken into account in this theory. An example typical for the nuclear situation shows the improvement of this new approach over the standard Local Density Approximation. We also show that if in this approach some shell fluctuations are introduced in the level density, the arch structure displayed by the quantal gaps along isotopic chains is almost recovered. We also point out that in heavy drip line nuclei pairing is strongly reduced

    La main-d’oeuvre hautement qualifiée au Canada

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    Cet article présente une analyse descriptive de certaines caractéristiques de la main-d'oeuvre hautement qualifiée au Canada. Une comparaison est également établie entre les diverses provinces canadiennes et plus particulièrement entre le Québec et l’Ontario.In 1973, Statistics Canada in cooperation with the Ministry for Science and Technology surveyed 138,000 persons who reported possessing a university degree in the 1971 Census. This Post-Censal Survey is completed and its data has been used for the computation of matrices which provide significant information on the Highly Qualified Manpower (HQM) supply in Canada. The author analyses the various educational and employment characteristics, and compares the HQM of the provinces, particularly that of Québec and Ontario. The article points out the difficulties met by theresearcher who embarks on the study of education-employment complex and the way it works. Difficulties met in manpower forecasting are also emphasized.Summary of results. The derived ratio HQM/population per province of residence places Ontario first among the provinces, Alberta second, British Columbia third, Manitoba fourth, Nova-Scotia fifth, Québec sixth, etc. It means that these provinces have a larger ratio of HQM per population and the benefit of a relatively more valuable economic resource.Education is the major activity field of university graduates (33.5%). This occupational sector being saturated, graduates will face more difficulties in finding jobs. While agriculture provides only 1% of HQM occupations, and mining and industry, 10.9%, the services, excluding teaching, represent 42.5% of occupations. There are no major differences in these proportions among the provinces, though variations exist in certain industries. It is worth noting that the percentage of graduates at the three levels of public administration is about 10%, which is representative of the welfare state in which we live. About 12% of graduates mention "no occupation" as their job of longest duration in the twelve months preceding the Survey.Five to ten years after graduation, the occupational mobility is far-reaching. It is evident that different trainings give access to a plurality of occupations, and that a certain occupation may be fulfilled by individuals coming from a variety of trainings. This underlines the existence of complementarity and substitution in any human capital. Moreover, the occupational mobility suggests that mathematicians, economists, geographers, historians, etc. describe an individual who acquired certain skills in disciplines which could be considered as specific professions, but these skills are transferable from function to function in a large number of occupations. This contributes to the complexity in the education-employment links and to the difficulties in manpower forecasting.The article does not give any recommendation, but underlines the situation of the Québec HMQ and the need to diversify it

    Public Deliberation and Epistemic Parity in Direct Democracies

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    In a context of public-policy making, I propose to consider a fundamental norm of epistemic parity as contributing to the justification, the acceptability and the legitimacy of decisions taken through deliberative processes. I also suggest that models of semi-direct democracy, whose constitutional foundations include the possibility of deliberations among all citizens sanctioned by popular votes, promote epistemic parity

    La formation et l'emploi des dipl√īmes en beaux-arts, en humanit√©s et en sciences sociales au Canada

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    Higher education in Canada has experienced a large expansion in the last decade. The student population grew by 15 percent per year, which raised the proportion of the 18-24 year old age group participating in post-secondary education from 10.2 percent in 1960-1961 tol 7.4 percent for men and from 3.3 percent to 9.8 percent for women. During the same period, the support allocated to this sector of education increased by 20 percent per year. In Quebec, for example, while the P.N.B. increased by 8.6 per year and the number of students grew by 13 percent, the operating costs of higher education grew by 23.5 percent per year.1 The cost of this education and the difficult economic situation lead us to review the question of development and role. In this article, we shall limit ourselves to degrees in fine arts, humanities, and social sciences in Canada, having dealt elsewhere with the other major categories of highly qualified manpower (MHQ)2. The post-census inquiry data on MHQ prepared in 1973 by Statistics Canada for the Ministry of State for science and technology serves as the basis for our study.L'enseignement sup√©rieur au Canada a connu une expansion consid√©rable durant la derni√®re d√©cennie. La population √©tudiante croissa de 15% par an, ce qui porta la proportion du groupe d'√Ęge 18-24 ans au post-secondaire de 10.2% en 1960-61 √† 17.4% pour les hommes et de 3.3% √† 9.8% pour les femmes. Parall√®lement, les sommes affect√©es √† ce niveau d'en- seignement augment√®rent de 20% par an. Au Qu√©bec, par exemple, tandis que le P.N.B. augmentait de 8.6% par an et que les effectifs √©tudiants progressaient de 13%, les d√©penses de fonctionnement de l'enseignement sup√©rieur ont cr√Ľ de 23.5% par an. Le co√Ľt de cet enseignement et une situation √©conomique difficile nous am√®nent √† revoir la question de la formation et l'emploi. Dans cet article nous allons nous limiter aux dipl√īm√©s en beaux-arts, en humanit√©s et en sciences sociales au Canada, ayant trait√© ailleurs des autres grands groupes de la main-d'oeuvre hautement qualifi√©e (MHQ). Les donn√©es de l'enqu√™te post-censitaire sur la MHQ men√©e par Statistique Canada en 1973 pour le minist√®re d'Etat aux sciences et √† la technologie servent de base √† notre travail

    Surface behaviour of the pairing gap in a slab of nuclear matter

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    The surface behaviour of the pairing gap previously studied for semi-infinite nuclear matter is analyzed in the slab geometry. The gap-shape function is calculated in two cases: (a) pairing with the Gogny force in a hard-wall potential and (b) pairing with the separable Paris interaction in a Saxon-Woods mean-field potential. It is shown that the surface features are preserved in the case of slab geometry, being almost independent of the width of the slab. It is also demonstrated that the surface enhancement is strengthened as the absolute value of chemical potential ‚ą£őľ‚ą£|\mu| decreases which simulates the approach to the nucleon drip line.Comment: 12 pages, 2 figure
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