Binary Decay of Light Nuclear Systems

A review of the characteristic features found in fully energy-damped, binarydecay yields from light heavy-ion reactions with $20\leq A_{target} + A_{projectile}\leq 80$ is presented. The different aspects of these yields that have been used to support models of compound-nucleus (CN) fission and deep-inelastic dinucleus orbiting are highlighted. Cross section calculations based on the statistical phase space at different stages of the reaction are presented and compared to the experimental results. Although the statistical models are found to reproduce most of the observed experimental behaviors, an additional reaction component corresponding to a heavy-ion resonance or orbiting mechanism is also evident in certain systems. The system dependence of this second component is discussed. The extent to which the binary yields in very light systems $(A_{CN} \leq 32)$ can be viewed as resulting from a fusion-fission mechanism is explored. A number of unresolved questions, such as whether the different observed behaviors reflect characteristically different reaction times, are discussed.Comment: 79 pages REVTeX file, 39 ps Figures included - to be publihed in Physics Report

Rastreabilidade em cadeias agroindustriais: conceitos e aplicações.

bitstream/CNPDIA-2009-09/11845/1/CiT33_2006.pd

Lipid-modulated assembly of magnetized iron-filled carbon nanotubes in millimeter-scale structures

Biomolecule-functionalized carbon nanotubes (CNTs) combine the molecular recognition properties of biomaterials with the electrical properties of nanoscale solid state transducers. Application of this hybrid material in bioelectronic devices requires the development of methods for the reproducible self-assembly of CNTs into higher-order structures in an aqueous environment. To this end, we have studied pattern formation of lipid-coated Fe-filled CNTs, with lengths in the 1–5 µm range, by controlled evaporation of aqueous CNT-lipid suspensions. Novel diffusion limited aggregation structures composed of end-to-end oriented nanotubes were observed by optical and atomic force microscopy. Significantly, the lateral dimension of assemblies of magnetized Fe-filled CNTs was in the millimeter range. Control experiments in the absence of lipids and without magnetization indicated that the formation of these long linear nanotube patterns is driven by a subtle interplay between radial flow forces in the evaporating droplet, lipid-modulated van der Waals forces, and magnetic dipole–dipole interactions. Keywords

Semente genética de soja - origem e procedimentos técnicos de produção - série sementes.

Primeira fase de seleção. Segunda fase de seleção.bitstream/CNPSO-2009-09/28932/1/circtec66.pd

Origin of the bilateral structure of the supernova remnant G296.5+10

In this work, we have modelled the supernova remnant (SNR) G296.5+10, by means of 3D magnetohydrodynamics (MHD) simulations. This remnant belongs to the bilateral SNR group and has an additional striking feature: the rotation measure (RM) in its eastern and western parts are very different. In order to explain both the morphology observed in radio-continuum and the RM, we consider that the remnant expands into a medium shaped by the superposition of the magnetic field of the progenitor star with a constant Galactic magnetic field. We have also carried out a polarization study from our MHD results, obtaining synthetic maps of the linearly polarized intensity and the Stokes parameters. This study reveals that both the radio morphology and the reported RM for G296.5+10 can be explained if the quasi-parallel acceleration mechanism is taking place in the shock front of this remnant.Fil: Moranchel-Basurto, A.. Universidad Nacional Autónoma de México; MéxicoFil: Velazquez, P.. Universidad Nacional Autónoma de México; MéxicoFil: Giacani, Elsa Beatriz. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo; Argentina. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Toledo Roy, J. C.. Universidad Nacional Autónoma de México; MéxicoFil: Schneiter, E.. Universidad Nacional Autónoma de México; MéxicoFil: De Colle, F.. Universidad Nacional Autónoma de México; MéxicoFil: Esquivel, A.. Universidad Nacional Autónoma de México; Méxic

A questão da assimetria da informação e da incerteza da qualidade na indústria de alimentos: soluções possíveis.

Ocorrências de contaminações alimentares associadas ao ambiente comercial competitivo resultaram, na última década, em maior atenção à qualidade e segurança do alimento, tanto em ambito mundial como no mercado nacional. A predominância de atributos de experiência e de crença nos produtos alimentares acentuam os problemas de assimetria da informação entre os agentes de uma transação e permitem, por exemplo, que produtos com qualidades distintas sejam comercializados a preços semelhantes e dificultam a percepção do mercado sobre diferenças efetivas na qualidade dos produtos. Por meio de revisão bibliográfica, e de dados secundários, este trabalho apresenta os principais mecanismos que têm sido utilizados para minimizar esses problemas, tais como: a intervenção do Estado; a utilização da marca como sinalizador de diferenciação; a prática de rastreabilidade do produto e do sistema de produção e a adoção da certificação da qualidade e da segurança do produto. De forma geral observa-se que tais práticas têm induzido à adoção de formas de organização mistas, por meio da coordenação vertical e horizontal, nas cadeias de produção de alimentos