1,768 research outputs found

    Efficient and weak efficient points in vector optimization with generalized cone convexity

    Get PDF
    AbstractIn this paper, we present necessary and sufficient conditions of efficiency and weak efficiency under generalized cone-convexity and cone-subconvexity. The results are stated in partially ordered real linear spaces from a separation theorem between convex cones which need not be solid

    Organization of production and the distribution of labor income in Spain

    Get PDF
    This paper examines evidences of market labor income inequality in Spain, as if they were the outcome of the market equilibrium from occupational choices of individuals with different general skills. We find that the parameters of the distribution of skills, production technology, and internal organization of firms that match the observed organization of production (number of persons occupied as employees, entrepreneurs-managers and solo self-employed, distribution of firm sizes) in Spain, also explain reasonably well the distribution of market labor income, within groups and for all occupied individuals together. The proposed model can be of use in evaluating the potential consequences for labor income inequality of changes in the organization of production

    Firm size and productivity from occupational choices

    Get PDF
    We model the distributions of firm sizes and of firms’ total factor productivity (TFP) as outcomes of a market equilibrium from the occupational decisions of individuals with different entrepreneurial skills, of working as employees, employers, or solo entrepreneurs. The model explains empirical regularities such as (i) the positive cross-section correlation between average size of firms and average labor productivity of countries, (ii) the positive association between size and TFP of firms in an economy, and (iii) the power law distribution of firm sizes. Two parameters of the model, one that measures the organizational size diseconomies and other related to the dispersion of the distribution of entrepreneurial skills in the population, appear as main determinants of the differences in firm sizes and in productivity, across economies and among firms within an economy. The results of the paper should be of interest for the design and evaluation of firm-size-dependent policies

    Generalized Ardehali-Bell inequalities for graph states

    Full text link
    We derive Bell inequalities for graph states by generalizing the approach proposed by Ardehali [Phys. Rev. A 46, 5375 (1992)] for Greenberger-Horne-Zeilinger (GHZ) states. Using this method, we demonstrate that Bell inequalities with nonstabilizer observables are often superior to the optimal GHZ-Mermin-type (or stabilizer-type) Bell inequalities.Comment: 6 pages, 3 figure

    Nonlocality without inequalities has not been proved for maximally entangled states

    Get PDF
    Two approaches to extend Hardy's proof of nonlocality without inequalities to maximally entangled states of bipartite two-level systems are shown to fail. On one hand, it is shown that Wu and co-workers' proof [Phys. Rev. A 53, R1927 (1996)] uses an effective state which is not maximally entangled. On the other hand, it is demonstrated that Hardy's proof cannot be generalized by the replacement of one of the four von Neumann measurements involved in the original proof by a generalized measurement to unambiguously discriminate between non-orthogonal states.Comment: 7 pages, 2 figures. To appear in Phys. Rev.

    P82 238. ¿Es segura la reintervención dejando los injertos arteriales permeables sin clampar?

    Get PDF
    ObjetivoEl objetivo de no dañar la arteria mamaria evitando su disección y clampaje supone un reto para la protección miocárdica debido al lavado de la cardioplejía.Presentamos nuestra experiencia en reintervenciones sin disecar ni clampar los injertos arteriales.Material y métodosDesde septiembre de 2000 hasta febrero de 2010 se realizaron 29 reintervenciones en 28 pacientes, (89,7% varones), edad media 73,17±7,38años. Las causas de reoperación fueron: progresión de valvulopatía 17 pacientes (58,6%), endocarditis 10 (34,4%), disfunción protésica no estructural 2 (6,9%). La mediana del EuroS-CORE logístico fue 14,84 (4-77,25). La cirugía fue urgente en 7 pacientes. Se realizó sustitución valvular aórtica aislada en 18 y se asoció revascularización en 4, sustitución/plastia mitral en 4, sustitución de aorta en 2; sustitución mitral aislada en 1.La protección miocárdica se realizó con cardioplejía hemática con esmolol, K+ y Mg+, administrándola siempre que no dificultaba el trabajo quirúrgico (intervalos nunca > 20min). Temperatura sistémica media 32,26±3,23 °C.ResultadosLa mediana del tiempo de circulación extracorpórea (CEC) fue 153 (91-494) y de clampaje 103 (71-430)min. Presentaron infarto postoperatorio 1 paciente (3,4%) y síndrome de bajo gasto postoperatorio 2 pacientes (6,5%). La mediana de troponina I postoperatoria fue 7,03ng/ml (1,84-109,5). La mortalidad hospitalaria fue 3 pacientes (10,3%) (cirugía urgente por endocarditis). Las causas de mortalidad fueron: daño neurológico irreversible (1 paciente), sepsis y bajo gasto (2 pacientes). La mediana de estancia hospitalaria fue 7 (1-33) días.ConclusiónEn nuestra experiencia, sin clampar los injertos arteriales y con la estrategia descrita, la protección miocárdica parece adecuada y la mortalidad hospitalaria aceptable

    Bell's inequality for n spin-s particles

    Get PDF
    The Mermin-Klyshko inequality for n spin-1/2 particles and two dichotomic observables is generalized to n spin-s particles and two maximal observables. It is shown that some multiparty multilevel Greenberger-Horne-Zeilinger states [A. Cabello, Phys. Rev. A 63, 022104 (2001)] maximally violate this inequality for any s. For a fixed n, the magnitude of the violation is constant for any s, which provides a simple demonstration and generalizes the conclusion reached by Gisin and Peres for two spin-s particles in the singlet state [Phys. Lett. A 162, 15 (1992)]. For a fixed s, the violation grows exponentially with n, which provides a generalization to any s of Mermin's conclusion for n spin-1/2 particles [Phys. Rev. Lett. 65, 1838 (1990)].Comment: REVTeX4, 4 page

    Prácticas de física : laboratorio II

    Get PDF
    1 archivo PDF (86 páginas)Manual de laboratorio de prácticas de física

    Reactividad árido-álcali en áridos empleados para hormigón

    Get PDF
    The aim of this work is to contribute to the knowledge of the interactions between aggregates and the components of the interstitial phase of concrete and to determine whether those aggregates that are subsequently used in the manufacture of concrete are reagents and are therefore likely to undergo a progressive deterioration of their initial properties. An initial petrographic study of each aggregate is performed in order to be able to determine its subsequent behaviour and reactivity under the influence of various factors. The potential reactivity of different silicaceous aggregates (slates, gneiss, hornfels, granites, quartzite and serpentine) is then determined by a chemical method for evaluating the potential reactivity of aggregates and an accelerated method in mortar specimens, and finally the surface reactivity is investigated. The results of these studies suggest that some aggregates are able to react with the components of the interstitial phase of concrete. The existence of this kind of interaction is confirmed by the results of the surface investigations before and after the basic reaction.Este trabajo pretende contribuir al conocimiento de las reacciones de interacción entre los áridos y los componentes de la fase intersticial del hormigón y determinar si estos áridos, empleados posteriormente en la fabricación del hormigón, son reactivos y por tanto susceptibles de provocar una disminución progresiva de sus propiedades iniciales. Para la caracterización de cada árido se ha realizado un estudio petrográfico, fundamental a la hora de determinar su posterior comportamiento en términos de reactividad frente a diversos factores. Seguidamente, se ha analizado la reactividad potencial de diferentes áridos silicatados (pizarras, gneis, corneanas, granitos, cuarcita y serpentina) mediante los dos métodos normalizados existentes: el método químico para la determinación de la reactividad potencial de áridos y el método acelerado en probetas de mortero; y para contrastar ambos hemos seguido el método de la reactividad superficial. Los resultados determinan que algunos áridos son susceptibles de reaccionar con los componentes de la fase intersticial de hormigón. La observación de su textura antes y después del ataque denota la existencia de esta interacción

    Population structure of eleven Spanish ovine breeds and detection of selective sweeps with BayeScan and hapFLK

    Get PDF
    The goals of the current work were to analyse the population structure of 11 Spanish ovine breeds and to detect genomic regions that may have been targeted by selection. A total of 141 individuals were genotyped with the Infinium 50 K Ovine SNP BeadChip (Illumina). We combined this dataset with Spanish ovine data previously reported by the International Sheep Genomics Consortium (N = 229). Multidimensional scaling and Admixture analyses revealed that Canaria de Pelo and, to a lesser extent, Roja Mallorquina, Latxa and Churra are clearly differentiated populations, while the remaining seven breeds (Ojalada, Castellana, Gallega, Xisqueta, Ripollesa, Rasa Aragonesa and Segureña) share a similar genetic background. Performance of a genome scan with BayeScan and hapFLK allowed us identifying three genomic regions that are consistently detected with both methods i.e. Oar3 (150–154 Mb), Oar6 (4–49 Mb) and Oar13 (68–74 Mb). Neighbor-joining trees based on polymorphisms mapping to these three selective sweeps did not show a clustering of breeds according to their predominant productive specialization (except the local tree based on Oar13 SNPs). Such cryptic signatures of selection have been also found in the bovine genome, posing a considerable challenge to understand the biological consequences of artificial selection.Publishe
    • …
    corecore