Four Dimensional Orbit Spaces of Compact Coregular Linear Groups

All four dimensional orbit spaces of compact coregular linear groups have been determined. The results are obtained through the integration of a universal differential equation, that only requires as input the number of elements of an integrity basis of the ideal of polynomial invariants of the linear group. Our results are relevant and lead to universality properties in the physics of spontaneous symmetry breaking at the classical level.Comment: 23 pages, plain LaTeX, a review that has not distributed regularl

The meat market in Brazil: an econometric approach.

We describe the relative participation of the meat market (beef, pork and chicken) in Brazil in the total agribusiness and in total country?s exports. An analysis of the world meat market is carried out from the point of view of the values of consumption, production, exports and imports. A multi-criteria DEA (Data Envelopment Analysis) approach is then used to generate world market classifications. Particularly, the Brazilian insertion in the world market is viewed from these perspectives. A partial equilibrium model for the meat market is fit to Brazilian data by three stages least squares. The model is consistent with the data and is used for simulation purposes. In this context we investigate the joint and the separate effects of changes in corn price and in the exchange rate on the market endogenous variables, ceteris paribus

Sonho, desafio e tecnologia: 35 anos de contribuições da Embrapa Suínos e Aves.

bitstream/item/105259/1/publicacao-1z33f2s.pdfProjeto: 11.11.11.111

Geometric invariant theory approach to the determination of ground states of D-wave condensates in isotropic space

A complete and rigorous determination of the possible ground states for D-wave pairing Bose condensates is presented, using a geometrical invariant theory approach to the problem. The order parameter is argued to be a vector, transforming according to a ten dimensional real representation of the group $G=${\bf O}$_3\otimes${\bf U}$_1\times$. We determine the equalities and inequalities defining the orbit space of this linear group and its symmetry strata, which are in a one-to-one correspondence with the possible distinct phases of the system. We find 15 allowed phases (besides the unbroken one), with different symmetries, that we thoroughly determine. The group-subgroup relations between bordering phases are pointed out. The perturbative sixth degree corrections to the minimum of a fourth degree polynomial $G$-invariant free energy, calculated by Mermin, are also determined.Comment: 27 revtex pages, 2 figures, use of texdraw; minor changes in the bibliography and in Table II

Variations in Biodistribution and Acute Response of Differently Shaped Titania Nanoparticles in Healthy Rodents

Biodistribution; Nanotoxicity; Physico-chemical propertiesBiodistribución; Nanotoxicidad; Propiedades fisicoquímicasBiodistribució; Nanotoxicitat; Propietats fisicoquímiquesTitanium dioxide nanoparticles (TiO2 NPs) are one of the main sources of the nanoparticulate matter exposure to humans. Although several studies have demonstrated their potential toxic effects, the real nature of the correlation between NP properties and their interaction with biological targets is still far from being fully elucidated. Here, engineered TiO2 NPs with various geometries (bipyramids, plates, and rods) have been prepared, characterized and intravenously administered in healthy mice. Parameters such as biodistribution, accumulation, and toxicity have been assessed in the lungs and liver. Our data show that the organ accumulation of TiO2 NPs, measured by ICP-MS, is quite low, and this is only partially and transiently affected by the NP geometries. The long-lasting permanence is exclusively restricted to the lungs. Here, bipyramids and plates show a higher accumulation, and interestingly, rod-shaped NPs are the most toxic, leading to histopathological pulmonary alterations. In addition, they are also able to induce a transient increase in serum markers related to hepatocellular injury. These results indicate that rods, more than bipyramidal and spherical geometries, lead to a stronger and more severe biological effect. Overall, small physico-chemical differences can dramatically modify both accumulation and safety.This research was funded by National Key Research and Development Program of China (No. 2017FYA0205301), Projects of International Cooperation and Exchanges NSFC (No. 82020108017), National Natural Science Foundation of China (No. 82272821); MCIN/AEI (PID2019-111218RB-I00 and RYC-2017-23457) and Centro Singular De Investigación de Galicia Accreditation 2019−2022, and ED431G 2019/03. Moreover, parts of this work were funded by the Cluster of Excellence ‘Advanced Imaging of Matter’ of the Deutsche Forschungsgemeinschaft (DFG)-EXC 2056-project ID 390715994; by Deutscher Akademischer Austauschdienst (DAAD); and by an Alexander von Humboldt fellowship. G.S. is supported by the Italian Association for Cancer Research (AIRC), grants 22820 and 22737. NGB and VP receive financial support from the Spanish Ministerio de Ciencia, Innovación y Universidades (MCIU) (RTI2018-099965-B-I00, AEI/FEDER, UE) proyectos de I + D + i de programación conjunta internacional MCIN/AEI (CONCORD, PCI2019-103436), co-funded by the European Union. P.B. is supported by the CONCORD project (EuroNanoMed III)