136 research outputs found

    A New Coupling Potential for the Scattering of Deformed Light Heavy-Ions

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    This letter introduces a new coupling potential to explain the experimental data over wide energy ranges for a number of systems. Within the coupled-channels formalism, this letter first shows the limitations of the standard coupled-channels theory in the case where one of the nuclei in the reaction is strongly deformed and then, demonstrates that a global solution to the problems of light heavy-ion reactions such as 12^{12}C+12^{12}C, 16^{16}O+28^{28}Si and 12^{12}C+24^{24}Mg can be found using a new second-derivative coupling potential in the coupled-channels formalism. This new approach consistently improves the agreement with the experimental data for the elastic and inelastic scattering data as well as for their excitation functions using constant or slightly energy-dependent parameters.Comment: 4 Pages, 5 Figures, submitted to the Phys. Lett.

    ¿Algo de la esencia del ser resuena como (objeto) voz en el pasador?

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    Lo que aquí se propone el autor será un armado, un recorrido, una puesta en relación del marco teórico del Dispositivo del Pase, con lo que le debemos a la experiencia psicoanalítica y el material testimonial de Pasadores, nominados con el título de Analistas de Escuela y Carteles, con el objetivo de establecer una correlación posible entre este dispositivo y el proceso analítico, destacando en ese cruce la importancia de la voz como objeto a. En el Dispositivo del Pase se trataría de cernir un saber correlativo a un cambio de posición del candidato en relación al saber, cierta certeza del encuentro con ese saber, junto a la caída del sujeto supuesto al saber, lo que determina el ingreso a la operación del Pase.Eje temático: PsicoanálisisFacultad de Psicologí

    Processamento de Titanato de Cobre e Cálcio (CCTO) Pelo Método dos Precursores Poliméricos para Aplicação em Dispositivos Fotoluminescentes.

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    Cerâmicas a base de CaCu₃Ti₄O₁₂ (CCTO) têm despertado grande interesse científico e tecnológico após a descoberta da sua elevada constante dielétrica. Uma outra propriedade dos titanatos e sua característica óptica que tem despertando grande interesse entre os pesquisadores. Neste projeto de pesquisa, obteve-se pós cerâmicos CCTO pelo método dos precursores poliméricos (Pechini) com propriedade fotoluminescente em função do grau de ordem e desordem dos pós-processados. Os pós-obtidos após processamento foram caracterizados por: termogravimetria, para verificar as faixas de temperatura em que o material processado tem perda de massa; difração de raios-X, para determinar a estrutura cristalográfica e estimar os tipos de defeitos desenvolvidos; espectroscopia no infravermelho com transformada de Fourier, para analisar os diferentes modos de vibração apresentados pelo material; espectroscopia Raman, para caracterizar e identificar as unidades estruturais do material e fotoluminescência para constatar a validade do método na obtenção de compostos que possam ser utilizados como dispositivos luminescentes

    ¿Algo de la esencia del ser resuena como (objeto) voz en el pasador?

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    Lo que aquí se propone el autor será un armado, un recorrido, una puesta en relación del marco teórico del Dispositivo del Pase, con lo que le debemos a la experiencia psicoanalítica y el material testimonial de Pasadores, nominados con el título de Analistas de Escuela y Carteles, con el objetivo de establecer una correlación posible entre este dispositivo y el proceso analítico, destacando en ese cruce la importancia de la voz como objeto a. En el Dispositivo del Pase se trataría de cernir un saber correlativo a un cambio de posición del candidato en relación al saber, cierta certeza del encuentro con ese saber, junto a la caída del sujeto supuesto al saber, lo que determina el ingreso a la operación del Pase.Eje temático: PsicoanálisisFacultad de Psicologí

    A Systematic Investigation of Light Heavy-Ion Reactions

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    We introduce a novel coupling potential for the scattering of deformed light heavy-ion reactions. This new approach is based on replacing the usual first-derivative coupling potential by a new, second derivative coupling potential in the coupled-channels formalism. The new approach has been successfully applied to the study of the 12^{12}C+12^{12}C, 12^{12}C+24^{24}Mg, 16^{16}O+28^{28}Si and 16^{16}O+24^{24}Mg systems and made major improvements over all the previous coupled-channels calculations for these systems. This paper also shows the limitations of the standard coupled-channels theory and presents a global solution to the problems faced in the previous theoretical accounts of these reactions.Comment: 7 pages with 4 figure

    New Results in the Analysis of the 16^{16}O+28^{28}Si Elastic Scattering by Modifying the Optical Potential

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    The elastic scattering of the 16^{16}O+28^{28}Si system has been analyzed with a modified potential within the framework of the optical model over a wide energy range in the laboratory system from 29.0 to 142.5 MeV. This system has been extensively studied over the years and a number of serious problems has remained unsolved: The explanation of the anomalous large angle scattering data; the out-of-phase problem between theoretical predictions and experimental data; the reproduction of the oscillatory structure near the Coulomb barrier; the consistent description of angular distributions together with the excitation functions data are just some of these problems. We propose the use of a modified potential method to explain these problems over this wide energy range. This new method consistently improves the agreement with the experimental data and achieves a major improvement on all the previous Optical model calculations for this system.Comment: 19 pages with 8 figure

    Dynein Function and Protein Clearance Changes in Tumor Cells Induced by a Kunitz-Type Molecule, Amblyomin-X

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    Amblyomin-X is a Kunitz-type recombinant protein identified from the transcriptome of the salivary glands of the tick Amblyomma cajennense and has anti-coagulant and antitumoral activity. the supposed primary target of this molecule is the proteasome system. Herein, we elucidated intracellular events that are triggered by Amblyomin-X treatment in an attempt to provide new insight into how this serine protease inhibitor, acting on the proteasome, could be comparable with known proteasome inhibitors. the collective results showed aggresome formation after proteasome inhibition that appeared to occur via the non-exclusive ubiquitin pathway. Additionally, Amblyomin-X increased the expression of various chains of the molecular motor dynein in tumor cells, modulated specific ubiquitin linkage signaling and inhibited autophagy activation by modulating mTOR, LC3 and AMBRA1 with probable dynein involvement. Interestingly, one possible role for dynein in the mechanism of action of Amblyomin-X was in the apoptotic response and its crosstalk with autophagy, which involved the factor Bim; however, we observed no changes in the apoptotic response related to dynein in the experiments performed. the characteristics shared among Amblyomin-X and known proteasome inhibitors included NF-kappa B blockage and nascent polypeptide-dependent aggresome formation. Therefore, our study describes a Kunitz-type protein that acts on the proteasome to trigger distinct intracellular events compared to classic known proteasome inhibitors that are small-cell-permeable molecules. in investigating the experiments and literature on Amblyomin-X and the known proteasome inhibitors, we also found differences in the structures of the molecules, intracellular events, dynein involvement and tumor cell type effects. These findings also reveal a possible new target for Amblyomin-X, i.e., dynein, and may serve as a tool for investigating tumor cell death associated with proteasome inhibition.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Butantan Inst, Biochem & Biophys Lab, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biochem, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biochem, São Paulo, BrazilFAPESP: 2011/05969-4FAPESP: CAT/CEPID 1998/14307-9FAPESP: CETICs 2013/07467-1Web of Scienc

    Morphological Evidence for an Oral Venom System in Caecilian Amphibians

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    Amphibians are known for their skin rich in glands containing toxins employed in passive chemical defense against predators, different from, for example, snakes that have active chemical defense, injecting their venom into the prey. Caecilians (Amphibia, Gymnophiona) are snake-shaped animals with fossorial habits, considered one of the least known vertebrate groups. We show here that amphibian caecilians, including species from the basal groups, besides having cutaneous poisonous glands as other amphibians do, possess specific glands at the base of the teeth that produce enzymes commonly found in venoms. Our analysis of the origin of these glands shows that they originate from the same tissue that gives rise to teeth, similar to the venom glands in reptiles. We speculate that caecilians might have independently developed mechanisms of production and injection of toxins early in their evolutionary history

    Melting of crystalline solids

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    It is suggested that at the melting temperature the thermal phonon vibration is in self-resonance with the lattice vibration of the surface atomic/molecular layer. This self resonance occurs at a well defined temperature and triggers the detachment of the atomic/molecular sheet or platelets from the surface of the crystal. Thermodynamic data of five substances is used to test this hypothesis. The calculated average phonon vibrational wavelengths are equal with or harmonics of the d-spacing of the atomic/molecular sheets. The proposed model is able to explain all of the features of melting.Comment: supercooling and ultra-fast speed of the phase transition is added as requirements for the explanation of meltin
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