178,238 research outputs found
Multiple homoclinic solutions for a class of autonomous singular systems in R2.
No full textWe look for homoclinic solutions for a class of second order autonomous Hamiltonian systems in R-2 with a potential V having a strict global maximum at the origin and a finite set S subset of R-2 of singularities, namely V(x) --> -infinity as dist(x,S) --> 0. We prove that if V satisfies a suitable geometrical property then for any k epsilon N the system admits a homoclinic orbit turning k times around a singularity xi epsilon S
Ruta 100 : testimonios / R. Flores Nolasco.
No full textReporte de Investigación para Lic. en Comunicación Social, Universidad Autónoma Metropolitana Xochimilc
Los otomíes. Análisis de un grupo marginal.. Anales del Instituto Nacional de Antropología e Historia. Num. 44 Tomo XV (1962) Sexta Época (1939-1966)
No full textComas, J. Manual de Antropología Física. México, 1957.Galenson, W. y Leibenstein, H. Criterios de Inversión, Productividad y Desarrollo Económico. Desarrollo Económico. Vol. 1, No. 2. Buenos Aires, 1955.Gonçalves de Souza, J. Aspects of Land Tenure Problems in Latin America. Rural Sociology. Vol. XXV, No. 1. Chicago, 1960.Lacoste, I. Los Países Subdesarrollados. Buenos Aires, 1960.Lajugie, J. Los Sistemas Económicos. Buenos Aires, 1960.Masseyeff, R. El Hambre. Buenos Aires, 1960.Mendizabal, M. O. de. Los problemas indígenas y su más urgente tratamiento. Obras Completas. T. V. México, 1946.Murdock, G. P. Social Structure. Nueva York, 1960.Nolasco Armas, M. El Hombre y el Maguey: Los Otomíes. Agro en México. Vol. l, No. 5. México, 1962.Nolasco Armas, M. Los Otomíes. Informe mecanoscrito entregado al Patrimonio Indígena del Valle del Mezquital. México, 1962.Olmedo, M. Sociedades Preclasistas. Las Fuerzas Productivas y las Relaciones de Producción en las Sociedades Precapitalistas. T. II. México, 1960.Oficina Internacional del Trabajo. Los Agricultores sin Tierra en América Latina. Ginebra, 1957.Patrimonio Indígena del Valle del Mezquital. Proyecto de Programa del Patrimonio Indígena del Valle del Mezquital. Edic. Mimeográfica, Itzmiquilpan, Hgo. México, 1954.Sand, R. LA Economía Humana. Buenos Aires, 1961.Sauvy, A. La Población. Buenos Aires, 1960.Svennilson, l. El Concepto del Crecimiento Económico. Revista de Estudios Agrarios. Año 1, No. 3. México, 1961.Unión Panamericana. Guía de Campo del Investigador Social. Manuales Técnicos, No. III. Washington, D.C, 1956.Unión Panamericana. Guía de Campo del Investigador Social. Manuales Técnicos, No. IV. Washington, D.C, 1957.Unión Panamericana. Guía de Campo del Investigador Social. Manuales Técnicos, No. V. Washington, D.C, 1960.Vivó, J. A. Razas y Lenguas Indígenas de México, 1941.Vivó, J. A. Aspectos Económicos y Fundamentales del Problema Indígena. América Indígena. Vol. III, No. 1. México, 1943.Vivó, J. A. Geografía de México. México, 1953.Whetten, N. L. México Rural. Problemas Agrícolas e Industriales de México. Vol. V, No. 2. México, 195
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Biophysical modelling of larval dispersal and population connectivity of a stalked barnacle: implications for fishery governance
No full textNolasco, R., Dubert, J., Acuña, J.L., Aguión, A., Cruz, T., Fernandes, J.N., Geiger, K.J., Jacinto, D., Macho, G., Mateus, D., Rivera, A., Román, S., Thiébaut, E., Vazquez, E., Queiroga, H
A variational approach to the Brown-Ravenhall operator for the relativistic one- electron atoms
No full textWe study the Brown–Ravenhall operator (the projection of the Dirac operator perturbed by a potential V ∈ L^3_w ) using the Foldy–Wouthuysen (unitary) transformation and its realization as an elliptic problem in the 4-dim half space R^4_+ with Neumann boundary condition. Using this approach we give a characterization of its eigenvalues and eigenfunctions alternative to the classical Rayleigh quotients
Ground state for the relativistic one electron atom in a self-generated electromagnetic field
No full textWe study the Dirac-Maxwell system coupled with an external potential of Coulomb type. We prove the existence of a ``ground state" solution using the Foldy-Wouthuysen (unitary) transformation of the Dirac operator and its realization as an elliptic problem in the 4-dim half space R^4_+ with a Neumann boundary condition
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Multiplicity of homoclinics for a class of time recurrent second order Hamiltonian systems.
No full textWe prove the existence of infinitely many homoclinic solutions for a class of second order Hamiltonian systems in R-N of the form q = q - W'(t,q), where we assume the existence of a sequence (t(n)) subset of R such that t(n) --> +/-infinity and W'(t + t(n),x) --> W'(t,x) as n --> +/-infinity for any (t,x) is an element of R x R-N. Moreover, under a suitable non degeneracy condition, we prove that this class of systems admits multibump solutions
Ground states for pseudo-relativistic equations with combined power and Hartree-type nonlinearities
No full textWe study the existence of ground state solutions for a class of
non-linear pseudo-relativistic Schr ̈odinger equations with combined focusing-
defocusing nonlinearity of power and Hartree-type. Such equations are characterized by a nonlocal pseudo-differential operator closely related to the square-root of the Laplacian. We apply variational methods to a related elliptic boundary problem on R^{N+1} with a suitable nonlinear Neumann boundary +
conditions
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