Sustainability perspectives: a new methodological approach for quantitative assessment

This paper proposes a new tool to assess sustainability and make the concept of sustainable development operational. It considers its multi-dimensional structure combining the information deriving from a selection of relevant sustainability indicators belonging to economic, social and environmental pillars. The main novelties of this approach are the modelling framework, a recursive-dynamic computable general equilibrium used to calculate the trend of all indicators over time throughout the world, and the aggregation methodology to reconcile them in one aggregate index to measure overall sustainability. The former allows capturing the sector and regional interactions and higher-order effects driven by background assumptions on relevant variables to depict future scenarios. The latter makes it possible to compare sustainability performances, under alternative scenarios, across countries and over time. Main results show that the current sustainability at world level differs from what the traditional measure of well-being, the GDP, depicts, highlighting the trade-offs among different components of sustainability. Moreover, in the next decade a slight decrease in world sustainability may occur, in spite of an expected increase in world domestic product. Finally, dedicated policies increase overall sustainability, showing that social and environmental benefits may be greater than the correlated economic costs

Evaluación de la reproducción inducida de nicuro Pimelodus blochii (Telostei: Pimelodidae) utilizando diferentes inductores hormonales

Objetivo. Evaluar el efecto de dos inductores hormonales en la reproducción inducida de nicuro Pimelodus blochii. Materiales y métodos. Para los procesos experimentales fueron utilizados adultos sexualmente maduros, sometidos a tres tratamientos aplicados vía intramuscular, en dosis única de 0.25 mL/kg Ovaprim® (OVAP) (T1), 0.5 mL/kg de OVAP (T2) y 6.25 mg/kg de Extracto de Hipófisis de Carpa (EHC) (T3), para este último tratamiento la inyección fue dividida en 20 y 80%, con un intervalo de 12 h entre aplicaciones. Previo a la extracción de los gametos, los animales fueron tranquilizados por inmersión en una solución de Metanosulfonato de Tricaina (90 mg/L). El desempeño reproductivo fue evaluado mediante el índice de ovulación (hembras ovuladas/hembras tratadas), fecundidad absoluta (Fa) (ovocitos/hembra), fecundidad relativa (Fr) en función del número de ovocitos desovados por gramo de peso. La fecundación se realizó en seco y seis horas post-fecundación (HPF) se determinó la tasa de fertilidad. Resultados. La ovulación (ºh) para el T1 fue a las 297.1±30.0, T2 294.6±32.9 y T3 247.3±13.1 ºh. En todos los tratamientos se obtuvieron hembras ovuladas, donde los mayores índices de ovulación fueron obtenidos con Ovaprim® (T1 y T2) con 36.4 y 50%, respectivamente. Las tasas de fecundación obtenidas fueron mayores a un 50%, para el tratamiento 1 y 2, con valores de 74.5 y 32.7%, respectivamente. Conclusiones. El uso de inductores hormonales puede ser efectivo para garantizar la reproducción inducida del nicuro, en dosis única de 0.25 y 0.5 mL/kg de Ovaprim®

Bi-conformal vector fields and their applications

We introduce the concept of bi-conformal transformation, as a generalization of conformal ones, by allowing two orthogonal parts of a manifold with metric \G to be scaled by different conformal factors. In particular, we study their infinitesimal version, called bi-conformal vector fields. We show the differential conditions characterizing them in terms of a "square root" of the metric, or equivalently of two complementary orthogonal projectors. Keeping these fixed, the set of bi-conformal vector fields is a Lie algebra which can be finite or infinite dimensional according to the dimensionality of the projectors. We determine (i) when an infinite-dimensional case is feasible and its properties, and (ii) a normal system for the generators in the finite-dimensional case. Its integrability conditions are also analyzed, which in particular provides the maximum number of linearly independent solutions. We identify the corresponding maximal spaces, and show a necessary geometric condition for a metric tensor to be a double-twisted product. More general ``breakable'' spaces are briefly considered. Many known symmetries are included, such as conformal Killing vectors, Kerr-Schild vector fields, kinematic self-similarity, causal symmetries, and rigid motions.Comment: Replaced version with some changes in the terminology and a new theorem. To appear in Classical and Quantum Gravit

Further properties of causal relationship: causal structure stability, new criteria for isocausality and counterexamples

Recently ({\em Class. Quant. Grav.} {\bf 20} 625-664) the concept of {\em causal mapping} between spacetimes --essentially equivalent in this context to the {\em chronological map} one in abstract chronological spaces--, and the related notion of {\em causal structure}, have been introduced as new tools to study causality in Lorentzian geometry. In the present paper, these tools are further developed in several directions such as: (i) causal mappings --and, thus, abstract chronological ones-- do not preserve two levels of the standard hierarchy of causality conditions (however, they preserve the remaining levels as shown in the above reference), (ii) even though global hyperbolicity is a stable property (in the set of all time-oriented Lorentzian metrics on a fixed manifold), the causal structure of a globally hyperbolic spacetime can be unstable against perturbations; in fact, we show that the causal structures of Minkowski and Einstein static spacetimes remain stable, whereas that of de Sitter becomes unstable, (iii) general criteria allow us to discriminate different causal structures in some general spacetimes (e.g. globally hyperbolic, stationary standard); in particular, there are infinitely many different globally hyperbolic causal structures (and thus, different conformal ones) on $\R^2$, (iv) plane waves with the same number of positive eigenvalues in the frequency matrix share the same causal structure and, thus, they have equal causal extensions and causal boundaries.Comment: 33 pages, 9 figures, final version (the paper title has been changed). To appear in Classical and Quantum Gravit

Short communication: Massive mortality in rabbits by maduramicin poisoning

[EN] A spontaneous outbreak of maduramicin intoxication in domestic rabbits (Oryctolagus cuniculus) is reported. It is believed that maduramicin incorporated as a coccidiostat into poultry pellet fed to rabbits was the cause, as up to 2.01 ppm was found in the samples and cardiopulmonary clinical signs in most of the rabbits was the common pattern. Findings here were consistent with the classic indications observed in ionophore toxicosis in different species, but little is known about the toxicity of maduramicin in rabbits.This study was partially supported by grants from CIC (Provincial Scientific Research Council), and SENASA (Argentina).Martino, P.; Parrado, E.; Sanguinetti, R.; Espinoza, C.; Debenedetti, R.; Di Benedetto, N.; Cisterna, C.... (2009). Short communication: Massive mortality in rabbits by maduramicin poisoning. World Rabbit Science. 17(1):45-48. https://doi.org/10.4995/wrs.2009.670454817

Symmetric hyperbolic systems for a large class of fields in arbitrary dimension

Symmetric hyperbolic systems of equations are explicitly constructed for a general class of tensor fields by considering their structure as r-fold forms. The hyperbolizations depend on 2r-1 arbitrary timelike vectors. The importance of the so-called "superenergy" tensors, which provide the necessary symmetric positive matrices, is emphasized and made explicit. Thereby, a unified treatment of many physical systems is achieved, as well as of the sometimes called "higher order" systems. The characteristics of these symmetric hyperbolic systems are always physical, and directly related to the null directions of the superenergy tensor, which are in particular principal null directions of the tensor field solutions. Generic energy estimates and inequalities are presented too.Comment: 24 pages, no figure

The causal ladder and the strength of K-causality. I

A unifying framework for the study of causal relations is presented. The causal relations are regarded as subsets of M x M and the role of the corresponding antisymmetry conditions in the construction of the causal ladder is stressed. The causal hierarchy of spacetime is built from chronology up to K-causality and new characterizations of the distinction and strong causality properties are obtained. The closure of the causal future is not transitive, as a consequence its repeated composition leads to an infinite causal subladder between strong causality and K-causality - the A-causality subladder. A spacetime example is given which proves that K-causality differs from infinite A-causality.Comment: 16 pages, one figure. Old title: ``On the relationship between K-causality and infinite A-causality''. Some typos fixed; small change in the proof of lemma 4.

Conformal geodesics in spherically symmetric vacuum spacetimes with cosmological constant

An analysis of conformal geodesics in the Schwarzschild-de Sitter and Schwarzschild-anti de Sitter families of spacetimes is given. For both families of spacetimes we show that initial data on a spacelike hypersurface can be given such that the congruence of conformal geodesics arising from this data cover the whole maximal extension of canonical conformal representations of the spacetimes without forming caustic points. For the Schwarzschild-de Sitter family, the resulting congruence can be used to obtain global conformal Gaussian systems of coordinates of the conformal representation. In the case of the Schwarzschild-anti de Sitter family, the natural parameter of the curves only covers a restricted time span so that these global conformal Gaussian systems do not exist.Comment: 51 pages, 12 figures. Minor changes. File updated. To appear in CQ