New age-metallicity diagnostic diagram for the Washington photometric system

The age calibration of the Washington deltaT1 index is mainly used to estimate ages of star clusters older than 1 Gyr, no age-metallicity degeneracy effect is considered. We have profusely exploited synthetic T1 versus C-T1 colour magnitude diagrams aiming at exploring the intrinsic behaviour of the deltaT1 index. The analysis shows that deltaT1 varies with age and metal content as well. In general, the dependence on age weakens for ages greater than ~ 6 Gyr, and results even less sensitive to age as the metallicity decreases. For ages younger than ~ 5 Gyr deltaT1 shows a strong correlation with both age and metallicity. The deltaC index -defined as deltaT1 for the C passband- is also a combined measurement of age and metallicity. We introduce a new age-metallicity diagnostic diagram, deltaT1 versus deltaC - deltaT1, which has shown the ability of unambiguously providing age and metallicity estimates, simultaneously. The new procedure allows to derive ages from 1 up to 13 Gyr and metallicities [Fe/H] from -2.0 up to +0.5 dex, and is independent of the cluster reddening and distance modulus. It does solve the constraints found in the deltaT1 index and surpasses the performance of the standard giant branch metallicity method. All these features make the diagnostic diagram a powerful tool for estimating accurate ages as well as metallicities.Comment: 14 pages, 7 figures, accepted for publication in MNRA

Nondiagonal CPmCP_m Coset Models and their Poincar\'E Polynomials

$N=2$ coset models of the type $SU(m+1)/SU(m)\times U(1)$ with nondiagonal modular invariants for both $SU(m+1)$ and $SU(m)$ are considered. Poincar\'e polynomials of the corresponding chiral rings of these algebras are constructed. They are used to compute the number of chiral generations of the associated string compactifications. Moddings by discrete symmetries are also discussed.Comment: 22 pages, (RevTex), preprint GTCRG-92-1 and CNEA-CAB-039/92. % Minor changes in the result

Estudio palinológico de las especies europeas del género Launeae Cass. (Compositae, Lactuceae)

Se estudian los carac.:teres palinológicos cualita ivos y cuantitativos , a M.O. y M.E. B., así como la estructura de la exina a M. E.B., de las seis especies europeas del género Launaea Cass . : L. a rbo r escens , L. cer vicor nis , L . fragi lis , L. lani f er a , L. nudicaulis y L. pumi la. Todas ellas presentan un tipo polínico común tricolpor orado, equi nolof'ado, con dos zonas polares y quince lagunas , subobl ato , y exina no caveadaQuali tati ve and quantitative palynol ogical characters were studied by L.M. and S. E.M., and exine structure by S . E. r~ . , in t he six european species of Launaea Cass . : L. ar bores cens , L. cervicornis , L. f ragilis , L . l anifer a , L. nudicaulis and L. pumila . A s i ngl e pollen type is common to all the species : tricolpor orate , echinol ophate , wi th fifteen l acunae a nd bolo polar are as , suboblate , wi th caveae absent

Missionary Scientists. Jesuit Science in Spanish South America, 1570-1810

Indexación: ScieloLa Compañía de Jesús, en los últimos diez años, se ha convertido en un verdadero laboratorio historiográfico en el cual proyectar perspectivas de análisis para el estudio de las misiones. Nuevas interpretaciones sobre el actuar de los misioneros y el examen de las redes políticas detrás de la Orden, hasta el cruce entre el plano local y el plano global configurado por las directrices romanas y las políticas imperiales, son algunas de las dimensiones analíticas que enriquecen la trayectoria histórica de esta orden que tuvo una presencia misionera en casi todos los rincones del mundo en época moderna

Structure of penetrable-rod fluids: Exact properties and comparison between Monte Carlo simulations and two analytic theories

Bounded potentials are good models to represent the effective two-body interaction in some colloidal systems, such as dilute solutions of polymer chains in good solvents. The simplest bounded potential is that of penetrable spheres, which takes a positive finite value if the two spheres are overlapped, being 0 otherwise. Even in the one-dimensional case, the penetrable-rod model is far from trivial, since interactions are not restricted to nearest neighbors and so its exact solution is not known. In this paper we first derive the exact correlation functions of penetrable-rod fluids to second order in density at any temperature, as well as in the high-temperature and zero-temperature limits at any density. Next, two simple analytic theories are constructed: a high-temperature approximation based on the exact asymptotic behavior in the limit $T\to\infty$ and a low-temperature approximation inspired by the exact result in the opposite limit $T\to 0$. Finally, we perform Monte Carlo simulations for a wide range of temperatures and densities to assess the validity of both theories. It is found that they complement each other quite well, exhibiting a good agreement with the simulation data within their respective domains of applicability and becoming practically equivalent on the borderline of those domains. A perspective on the extension of both approaches to the more realistic three-dimensional case is provided.Comment: 19 pages, 11 figures, 4 tables: v2: minor changes; published final versio

Milenarismo, espiritualismo y reforma eclesiástica en la Baja Edad Media

Tendo em vista as diversas doutrinas de corte milenarista, desde Joaquim de Fiore, até Jan Hus, tenta-se demonstrar que a sempre reivindicada reforma da igreja depende de uma determinada maneira de entender a vida espiritual.Considering several millennial doctrines, from Joachim of Fiore until Jan Hus, we seek to demonstrate that the reform of the Church depends on a particular understanding of spiritual life