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It is examined whether the number ($J$) of (joint) publications of a "main scientist" with her/his coauthors ranked according to rank ($r$) importance, i.e. $ J \propto 1/r $, as found by Ausloos [1] still holds for subfields, i.e. when the "main scientist" has worked on different, sometimes overlapping, subfields. Two cases are studied. It is shown that the law holds for large subfields. As shown, in an Appendix, is also useful to combine small topics into large ones for better statistics. It is observed that the sub-cores are much smaller than the overall coauthor core measure. Nevertheless, the smallness of the core and sub-cores may imply further considerations for the evaluation of team research purposes and activities., Comment: 12 figures (can be combined); 37 references; 4 Tables; prepared for and submitted to Scientometrics

Después de la crisis de la deuda de 1982, México empezó a instrumentar el programa que, al parecer, era el más liberal y abierto al exterior de su historia. La tendencia a la liberalización continuó a lo largo de la dé­cada de los ochenta y terminó recien­temente en el Tratado de Libre Co­mercio (TLC) con Canadá y Estados Unidos. En este artículo se analizan los vínculos entre las reformas de política impuestas por este programa y el desempeño económico del país durante 1985-1995. Las diversas me­didas y políticas adoptadas durante ese periodo han sido a menudo con­tradictorias e inconsistentes, y pare­cen haber desempeñado un papel principal como causantes de los actua­les problemas económicos que en­frenta México. El documento sos­tiene que así como la liberalización es importante para el crecimiento económico, lo es también para co­locar en su sitio un conjunto de políticas coherentes que puedan promover el crecimiento y evitar que el país pague una gran parte de las consecuencias negativas del proceso de ajuste.

The resistive transition R(T) between the Kosterlitz-Thouless temperature and the Ginzburg-Landau temperature was studied in spray-dried bulk Bi2Sr2CaCu2O8 + d superconductors for a magnetic-field range between 0 and 0.3 T. The samples were prepared by the spray-drying technique with Bi2 + xSr2 - x - yCa2 + yCu2O8 + d for x = y = 0.05 or 0.1 as a starting composition here. The data analysis was performed assuming various resistive laws previously proposed. When numerically analyzed in terms of a two-dimensional Kosterlitz-Thouless theory the results lead to remarkable quantitative agreement. This implies that the R(T) behavior can be described within a picture of a highly two-dimensional behavior of macroscopic fluctuations of vortex-antivortex depairing type. The role of defects or inhomogeneities in the resistive behavior is outlined. © 1995., SCOPUS: ar.j, info:eu-repo/semantics/published

info:eu-repo/semantics/published

info:eu-repo/semantics/published

The resistive transition R(T) between the Kosterlitz-Thouless temperature and the Ginzburg-Landau temperature was studied in spray-dried bulk Bi2Sr2CaCu2O8 + d superconductors for a magnetic-field range between 0 and 0.3 T. The samples were prepared by the spray-drying technique with Bi2 + xSr2 - x - yCa2 + yCu2O8 + d for x = y = 0.05 or 0.1 as a starting composition here. The data analysis was performed assuming various resistive laws previously proposed. When numerically analyzed in terms of a two-dimensional Kosterlitz-Thouless theory the results lead to remarkable quantitative agreement. This implies that the R(T) behavior can be described within a picture of a highly two-dimensional behavior of macroscopic fluctuations of vortex-antivortex depairing type. The role of defects or inhomogeneities in the resistive behavior is outlined. © 1995., SCOPUS: ar.j, info:eu-repo/semantics/published

The resistive behavior of single phase bulk Bi2Sr2CaCu2O8+δ superconductors has been studied in a magnetic field in the region between the percolation and superconductivity transitions. The samples used have been prepared by the spray drying technique with Bi2+xSr2-x-yCa2+yCu2O8+ δ for x = y = 0.05 or 0.1 as starting composition. The data analysis when performed in terms of two-dimensional Kosterlitz-Thouless theory leads to remarkable quantitative agreement, confirming the picture of highly two-dimensional behavior of macroscopic fluctuations (of vortex-antivortex depairing type) as discussed and found by Livanov et al. for similar thin films. © 1994., SCOPUS: ar.j, info:eu-repo/semantics/published

Thermoelectric power and thermal conductivity of YBa2(Cu1-xFex)3O7- δ polycrystals for 0

Int. Conf. M2S-HTSC IV Grenoble, 5-9/7/1994, info:eu-repo/semantics/published

Int. Conf. M2S-HTSC IV Grenoble, 5-9/7/1994, info:eu-repo/semantics/published

The behavior of the thermal conductivity κ of twinned YBa2Cu3O7-x and tweeded YBa2(Cu0.95Fe0.05)3O7-x polycrystals in a magnetic field up to 5 T is presented. Data as a function of field are shown to depart from the usual linear behavior of thermal magnetoresistivity (TMR) κ-1(B) for conventional superconductors. A set of stretched exponential laws, of the form κ-1(B) - κ-1 (O) = CBexp (-pNq) been found to describe our data with q decreasing with temperature from 1 to 1 2and from 1 2 to 1 4 for pure and iron-doped samples, respectively, in contrast to the unique interpolation formula (q = 1 4) for TMR proposed recently by Richardson et al. [1] to fit their data on twinned and untwinned single crystals. Such a complex behavior of TMR in the high fiels region is supposed to originate from extended defect mediated intrinsic proximity effect in both samples. The proposed interpretation is based on incorporating two types of phonon scatterers, free (unpinned) and pinned (by the defect cores) vortices, into a conventional picture of phonon-vortex scattering mechanism. © 1993., SCOPUS: ar.j, info:eu-repo/semantics/published

En un artículo reciente, Robert Baldwin (1992: 828), un teórico reconocido, se preguntó si los puntos de vista tradicionales para explicar el comercio inter­nacional son todavía válidos. Después de revisar los recientes desarrollos en la teoría del comercio, el autor concluye que lo que él llama "la nueva teoría del comercio” "será integrada en este mareo (tradicional) en lugar de reemplazarlo". De cualquier forma, Paul Krugman (I99ib:82), quien, en general, es conside­rado líder de la "nueva teoría del comercio", con base en un análisis de la Historia económica de Estados Unidos, concluye que "no es verdad que nuestra eco­nomía esté a hora bien descrita por el modelo convencional de beneficios constantes.