716 research outputs found
Leibniz algebroid associated with a Nambu-Poisson structure
The notion of Leibniz algebroid is introduced, and it is shown that each
Nambu-Poisson manifold has associated a canonical Leibniz algebroid. This fact
permits to define the modular class of a Nambu-Poisson manifold as an
appropiate cohomology class, extending the well-known modular class of Poisson
manifolds
Monetary policy and inflation persistence in the Eurozone
The primary goal of the European Central Bankâs (ECB) monetary policy is to achieve price stability. Whereas during the 1980s and 1990s there was a rapid and strong convergence in terms of price differential among the Euro countries, particularly in those countries with higher inflation rates in the past, single monetary policy has proved to be quite inefficient in continuing this trend and has not achieved further reductions in inflation rate differentials within the euro zone. Since the ECB sets the official interest rate according to the average inflation of the euro area, the persistence of such price differentials within the area would mean that the âone size interest rate policyâ would not fit all. This paper studies empirically the inflation rate differentials and their persistence in some currency unions with the aim to draw some conclusions for the working of the ECB monetary policy. KEYWORDS: monetary policy; inflation persistence; currency unions
The marine Neogene of Eastern Venezuela : a preliminary report
Proceedings of tile 1" R.C.A.N.S. Congress, Lisboa, October 1992The studied marine Neogene-Quaternary of NE Venezuela outcrop in the localities of the Araya peninsula and in the Cubagua and
Margarita islands discordant upon a basementof metamorphic rocks and pre-rniocenic sediments. These neogene-quaternary sections belong principally to the Cubagua Formation, which is composed of a lower clayish interval (Cerro Verde Member) and an upper one of calcareous nature (Cerro Negro Member), and to La Tejita and Tortuga formations.
The age of this sedimentary interval, based upon analysis of planktonic foraminifera, ranges from the lower part of Late Miocene
to Holocene. According to the calcareous nannoflora, in the Cubagua Formation a floral assemblage was identified which goes from the Zone NN10 until the limit of NN16-NN17 zones.
The fauna of benthic foraminifera allowed one to establish that the paleoenvironmental evolution of the Cubagua Formation varied
from bathial to neritic depths during the Early Pliocene.
After a period of elevation an erosion during the greater part of the Pleistocene, water invading the eroded surface depositing upon it the calcareous sequence of the Tortuga Formation
Kirillov structures and reduction of Hamiltonian systems by scaling and standard symmetries
In this paper, we discuss the reduction of symplectic Hamiltonian systems by
scaling and standard symmetries which commute. We prove that such a reduction
process produces a so-called Kirillov Hamiltonian system. Moreover, we show
that if we reduce first by the scaling symmetries and then by the standard ones
or in the opposite order, we obtain equivalent Kirillov Hamiltonian systems. In
the particular case when the configuration space of the symplectic Hamiltonian
system is a Lie group G, which coincides with the symmetry group, the reduced
structure is an interesting Kirillov version of the Lie-Poisson structure on
the dual space of the Lie algebra of G. We also discuss a reconstruction
process for symplectic Hamiltonian systems which admit a scaling symmetry. All
the previous results are illustrated in detail with some interesting examples
Contribution of microscopy for understanding the mechanism of action against trypanosomatids
Transmission electron microscopy (TEM) has proved to be a useful tool to study the ultrastructural alterations and the target organelles of new antitrypanosomatid drugs. Thus, it has been observed that sesquiterpene lactones induce diverse ultrastructural alterations in both T. cruzi and Leishmania spp., such as cytoplasmic vacuolization, appearance of multilamellar structures, condensation of nuclear DNA, and, in some cases, an important accumulation of lipid vacuoles. This accumulation could be related to apoptotic events. Some of the sesquiterpene lactones (e.g., psilostachyin) have also been demonstrated to cause an intense mitochondrial swelling accompanied by a visible kinetoplast deformation as well as the appearance of multivesicular bodies. This mitochondrial swelling could be related to the generation of oxidative stress and associated to alterations in the ergosterol metabolism. The appearance of multilamellar structures and multiple kinetoplasts and flagella induced by the sesquiterpene lactone psilostachyin C indicates that this compound would act at the parasite cell cycle level, in an intermediate stage between kinetoplast segregation and nuclear division. In turn, the diterpene lactone icetexane has proved to induce the external membrane budding on T. cruzi together with an apparent disorganization of the pericellar cytoskeleton. Thus, ultrastructural TEM studies allow elucidating the possible mechanisms and the subsequent identification of molecular targets for the action of natural compounds on trypanosomatids.Fil: Lozano, Esteban SebastiĂĄn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de Medicina y BiologĂa Experimental de Cuyo; ArgentinaFil: Spina Zapata, Renata MarĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Barrera, Patricia Andrea. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Tonn, Carlos Eugenio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Sosa Escudero, Miguel Angel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; Argentin
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