2,783 research outputs found

    Perspectiva estructuralista de la innovación : evaluación del entrenamiento en Andalucía como minoración del estrés

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    Este informe describe y compara percepciones desenvueltas de profesores' con ansiedad profesional sobre actividades de formacion permanente realizadas en Andalucía. Se contrastaron 20 hipótesis principales, curtidas en 89 subhipótesis. Los profesores no se distinguieron entre sí por variables de hondura contextual o condición demográfica. Se confirmaron las diferencias en el profesorado por algún factor articulador de actividades formativas: motiva participante, saberes adquiridos, contenido de cursos, calidad de acti--ción de vidades formativas y medida de la eficacia de cursos.__________________________________ This report describes and compares perceptions of teachers participating on in-service training activities in Andalucia with regard to professional anxiety. 20 main hypothesis were contrasted involving 89 subhypothesis. The teachers don't distinguish between them for contextual depth variables or demographic condition. The differences found among teachers were through factor which refer to formative activities: participant motivation, acquired knowledges, content of courses, quality of formative activities, and measurement of the efficacy of courses

    Impact of the new solar abundances on the calibration of the PMS binary system RS Cha

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    Context: In a recent work, we tried to obtain a calibration of the two components of the pre-main sequence binary system RS Cha by means of theoretical stellar models. We found that the only way to reproduce the observational parameters of RS Cha with standard stellar models is to decrease the initial abundances of carbon and nitrogen derived from the GN93 solar mixture of heavy elements by a few tenths of dex. Aims: In this work, we aim to reproduce the observational properties of the RS Cha stars with stellar evolution models based on the new AGS05 solar mixture recently derived from a three-dimensional solar model atmosphere. The AGS05 mixture is depleted in carbon, nitrogen and oxygen with respect to the GN93 mixture. Methods: We calculated new stellar models of the RS Cha components using the AGS05 mixture and appropriate opacity tables. We sought models that simultaneously satisfy the observations of the two components (masses, radii, luminosities, effective temperatures and metallicity). Results: We find that it is possible to reproduce the observational data of the RS Cha stars with AGS05 models based on standard input physics. From these models, the initial helium content of the system is Y~0.255 and its age is ~9.13 +- 0.12 Myr.Comment: Research note accepted in A&A, 5 pages, 2 figure

    Isotope analysis reveals foraging area dichotomy for Atlantic leatherback turtles

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    Background: The leatherback turtle (Dermachelys corlacea) has undergone a dramatic decline over the last 25 years, and this is believed to be primarily the results of mortality associated with fisheries bycatch followed by egg and nesting female harvest, Atlantic leatherback turtles undertake long migrations across ocean basins from subtropical and tropical nesting beaches to productive frontal areas; Migration between two nesting seasons can last 2 or 3 years, a time period termed the remigration interval (RI). Recent satellite transmitter data revealed that Atlantic leatherbacks follow two major dispersion patterns after nesting season, through the North Gulf Stream area or more eastward across the North Equatorial Current. However, information on the whole RI is lacking, precluding the accurate identification of feeding areas where conservation measures may need to be applied. Methodology/Principal Findings: Using stable isotopes as dietary tracers we determined the characteristics of feeding grounds of leatherback females nesting in French Guíana. During migration, 3-year RI females diffred from 2-year RI females in their isotope values, implying differences in their choice of feeding habitats (offshore vs. more coastal) and foraging latitude (North Atlantic vs. West African coasts, respectively). Egg-yolk and blood isotope values are correlated in nesting females, indicating that egg analysis is a useful tool for assessing isotope values in these turtles, including adults when not available. Conclusions/Significance: Our results complement previous data on turtle movements during the first year following the nesting season, integrating the diet consumed during the year before nesting. We suggest that the French Guiana leatherback population segregates into two distinct isotopic groupings, and highlight the urgent need to determine the feeding habitats of the turtle in the Atlantic in order to protect this species from incidental take by commercial fisheries. Our results also emphasize the use of eggs, a less-invasive sampling material than blood, to assess isotopic data and feeding habits for adult female leatherbacks

    Pragmatica, qve sv Magestad manda publicar, en orden al precio, y tassa, que han de tener los Granos que se compraren, y vendieren en estos Reynos

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    Caplletra xil. ornada a l'inici del textEscut reial xil. a port.Pragmàtica, 1699-08-17 : "EN la Villa de Madrid à diez y siete dias del més de Agosto de mil y seiscientos y noventa y nueve años"ReclamsSign.: A3Última pàgina : "Don Manuel Negrete y Angulo"Pragmàtica, que sa Majestat ordena publicar, en ordre al preu, i taxa, que han de tenir els Grans que es compressin, i venguessin en aquests Regnes.

    Conductance Distributions in Random Resistor Networks: Self Averaging and Disorder Lengths

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    The self averaging properties of conductance gg are explored in random resistor networks with a broad distribution of bond strengths P(g)\simg^{\mu-1}. Distributions of equivalent conductances are estimated numerically on hierarchical lattices as a function of size LL and distribution tail parameter μ\mu. For networks above the percolation threshold, convergence to a Gaussian basin is always the case, except in the limit μ\mu --> 0. A {\it disorder length} ξD\xi_D is identified beyond which the system is effectively homogeneous. This length diverges as ξDμν\xi_D \sim |\mu|^{-\nu} (ν\nu is the regular percolation correlation length exponent) as μ\mu-->0. This suggest that exactly the same critical behavior can be induced by geometrical disorder and bu strong bond disorder with the bond occupation probability ppμ\mu. Only lattices at the percolation threshold have renormalized probability distribution in a {\it Levy-like} basin. At the threshold the disorder length diverges at a vritical tail strength μc\mu_c as μμcz|\mu-\mu_c|^{-z}, with z=3.2±0.1z=3.2\pm 0.1, a new exponent. Critical path analysis is used in a generalized form to give form to give the macroscopic conductance for lattice above pcp_c.Comment: 16 pages plain TeX file, 6 figures available upon request.IBC-1603-01

    Forma que se ha de guardar en armar cavalleros, y dar los abitos profesiones, y colaziones de las Enmiendas a los Cavalleros de la Orden de Santiago

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    Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Esc. xil. en port.Sign.: []4, B-F

    Modeling the dynamic rupture propagation on heterogeneous faults with rate- and state-dependent friction

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    We investigate the effects of non-uniform distribution of constitutive parameters on the dynamic propagation of an earthquake rupture. We use a 2D finite difference numerical method and we assume that the dynamic rupture propagation is governed by a rate- and state-dependent constitutive law. We first discuss the results of several numerical experiments performed with different values of the constitutive parameters a (to account for the direct effect of friction), b (controlling the friction evolution) and L (the characteristic length-scale parameter) to simulate the dynamic rupture propagation on homogeneous faults. Spontaneous dynamic ruptures can be simulated on velocity weakening (a < b) fault patches: our results point out the dependence of the traction and slip velocity evolution on the adopted constitutive parameters. We therefore model the dynamic rupture propagation on heterogeneous faults. We use in this study the characterization of different frictional regimes proposed by Boatwright and Cocco (1996) based on different values of the constitutive parameters a, b and L. Our numerical simulations show that the heterogeneities of the L parameter affect the dynamic rupture propagation, control the peak slip velocity and weakly modify the dynamic stress drop and the rupture velocity. Moreover, a barrier can be simulated through a large contrast of L parameter. The heterogeneity of a and b parameters affects the dynamic rupture propagation in a more complex way. A velocity strengthening area (a > b) can arrest a dynamic rupture, but can be driven to an instability if suddenly loaded by the dynamic rupture front. Our simulations provide a picture of the complex interactions between fault patches having different frictional properties and illustrate how the traction and slip velocity evolutions are modified during the propagation on heterogeneous faults. These results involve interesting implications for slip duration and fracture energy
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