Federal University of São Carlos

About: Federal University of São Carlos is a education organization based out in São Carlos, Brazil. It is known for research contribution in the topics: Population & Microstructure. The organization has 16471 authors who have published 34057 publications receiving 456654 citations. The organization is also known as: UFSCar & Federal University of São Carlos.

Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil.

Abstract: The evolutionary events during the Ediacaran–Cambrian transition (~541 Myr ago) are unparalleled in Earth history. The fossil record suggests that most extant animal phyla appeared in a geologically brief interval, with the oldest unequivocal bilaterian body fossils found in the Early Cambrian. Molecular clocks and biomarkers provide independent estimates for the timing of animal origins, and both suggest a cryptic Neoproterozoic history for Metazoa that extends considerably beyond the Cambrian fossil record. We report an assemblage of ichnofossils from Ediacaran–Cambrian siltstones in Brazil, alongside U–Pb radioisotopic dates that constrain the age of the oldest specimens to 555–542 Myr. X-ray microtomography reveals three-dimensionally preserved traces ranging from 50 to 600 μm in diameter, indicative of small-bodied, meiofaunal tracemakers. Burrow morphologies suggest they were created by a nematoid-like organism that used undulating locomotion to move through the sediment. This assemblage demonstrates animal–sediment interactions in the latest Ediacaran period, and provides the oldest known fossil evidence for meiofaunal bilaterians. Our discovery highlights meiofaunal ichnofossils as a hitherto unexplored window for tracking animal evolution in deep time, and reveals that both meiofaunal and macrofaunal bilaterians began to explore infaunal niches during the late Ediacaran. Trace fossils from the Ediacaran–Cambrian transition of Brazil are interpreted as the remains of burrows made by a nematoid-like organism moving through sediment: these organisms are interpreted as the oldest known fossil meiofaunal bilaterians.

Gestão de tecnologia em universidades: uma análise do patenteamento e dos fatores de dificuldade e de apoio à transferência de tecnologia no Estado de São Paulo

Abstract: A gestao da tecnologia nas universidades publicas brasileiras tem ganhado crescente importância para o sistema de inovacao brasileiro. A Lei de Inovacao de 2004 forneceu diretrizes legais especificas acerca da propriedade intelectual, cooperacao tecnica e transferencia tecnologica favorecendo a intensificacao desses processos. O objetivo deste trabalho foi apreender as politicas institucionais e os desafios para a transferencia de tecnologia em universidades publicas do Estado de Sao Paulo, a saber: USP, Unesp, Unicamp, Unifesp e UFSCar, buscando identificar fatores de dificuldade e de apoio em processos de transferencia de tecnologia observados pelos agentes das universidades e empresas parceiras. A pesquisa, de tipo qualitativa, utilizou-se da estrategia de estudo multicaso e por meio da realizacao de entrevistas a respeito de contratos de transferencia de tecnologia foi realizada analise comparativa das universidades. Verificou-se um crescimento do patenteamento e da atividade de comercializacao de tecnologia em todos os casos, porem ainda recentes.

The Heisenberg XXZ Hamiltonian with Dzyaloshinsky-Moriya interactions

Abstract: The quantum Heisenberg chain with Dzyaloshinsky-Moriya interactions is solved by relating it to theXXZ Hamiltonian with a certain type of boundary conditions. Several properties of the ground state are derived which agree with the intuition derived from related soluble classical models. Implications to the model of known results from the theory of conformal invariance, as well as generalizations to higher spin, are briefly discussed.

Effect of the ceramic grain size and concentration on the dynamical mechanical and dielectric behavior of poly(vinilidene fluoride) Pb(Zr0.53Ti0.47)O3 composites

Abstract: In this work, poly(vinilidene fluoride)/Pb(Zr0.53Ti0.47)O3([PVDF]1−x /[PZT] x ) composites of volumetric fractions x and (0–3) type connectivity were prepared in the form of thin films. PZT powder of crystallite size of 0.84, 1.68, and 2.35 μm in different amounts of PZT (10, 20, 30, and 40%) was mixed with the polymeric matrix. The crystalline phase of the polymeric matrix was the nonpolar α-phase and the polar β-phase. Dielectric and dynamic mechanical (DMA) measurements were performed to these composites in order to evaluate the influence of particle size and the amount of PZT filler with respect to the PVDF matrix. The inclusion of ceramic particles in the PVDF polymer matrix increases the complex dielectric constant and dynamical mechanical response of the composites. A similar behavior is observed for the α- or β-phase of the polymeric matrix indicating that the PVDF polymer matrix is not particularly relevant for the composite behavior. On the other hand, ceramic size and especially content play the major role in the increase of the dielectric response and the room temperature storage modulus. In particular, the storage modulus increases with increasing PZT concentration, but this increase is more pronounced, in terms of maximum value, for the sample with 2.35 μm particle size; DMA reveals two main relaxations in the analyzed samples. A low-temperature process maximum at ca. −40°C, usually labeled by β or α a associated to the T g of the polymer and the α-relaxation at temperatures above 30°C. The β-relaxation is also observed in the dielectric measurements. The models used to asses the dielectric behavior of the samples with increasing PZT concentration indicate that the particle–matrix interaction plays a relevant role, as well as the particle asymmetry and relative orientation, being the Yamada model the most appropriate to describe the composite behavior.

Oriented attachment mechanism in anisotropic nanocrystals: a "polymerization" approach.

Abstract: The kinetic model of stepwise polymerization is revisited, with some adaptations for its application to the kinetics of oriented attachment of nanoparticles in colloidal suspensions, which results in the formation of anisotropic particles. A comparison with experimental data reported in the literature shows good agreement with the model and supports comparisons with other systems.