Bimetallic Pt-Ag and Pd-Ag Nanoparticles

We report studies of bimetallic nanoparticles with 15%-16% atomic crystal parameters size mismatch. The degree of alloying was probed in a 2-nm Pt core (smallest attainable core size) of Pt-Ag nanoparticles (completely immiscible in bulk) and 20-nm-diameter Pd-Ag nanowires (completely miscible in bulk). Particles were synthesized radiolytically, and depending on the initial parameters, they assume spherical or cylindrical (nanowire) morphologies. In all cases, the metals are seen to follow their bulk alloying characteristics. Pt and Ag segregate in both spherical and wire forms, which indicates that strain due to crystallographic mismatch overcomes the excess surface free energy in the small particles. The Pd-Ag nanowires alloy similar to previously reported spherical Pd-Ag particles of similar diameter and composition

Neurophysiological Measures and Alcohol Use Disorder (AUD): Hypothesizing Links between Clinical Severity Index and Molecular Neurobiological Patterns

In 1987, Cloninger proposed a clinical description and classification of different personality traits genetically defined and independent from each other. Moreover, he elaborated a specific test the TCI to investigate these traits/states. The study of craving in Alcohol Use Disorder (AUD) assumed a greater significance, since ever more data seems to suggest a direct correlation between high levels of craving and a higher risk of relapse in alcoholics. Thus, our study aim is to explore the possible correlations among TCI linked molecular neurobiological pattern (s), craving and alcohol addiction severity measures in a sample of Italian alcoholics

Dissipative dynamics of a qubit coupled to a nonlinear oscillator

We consider the dissipative dynamics of a qubit coupled to a nonlinear oscillator (NO) embedded in an Ohmic environment. By treating the nonlinearity up to first order and applying Van Vleck perturbation theory up to second order in the qubit-NO coupling, we derive an analytical expression for the eigenstates and eigenfunctions of the coupled qubit-NO system beyond the rotating wave approximation. In the regime of weak coupling to the thermal bath, analytical expressions for the time evolution of the qubit's populations are derived: they describe a multiplicity of damped oscillations superposed to a complex relaxation part toward thermal equilibrium. The long time dynamics is characterized by a single relaxation rate, which is maximal when the qubit is tuned to one of the resonances with the nonlinear oscillator.Comment: 24 pages, 7 figures, 1 table; in the text between Eq. (8) and (9) there were misprints in the published version until 3rd Dec 2009: in the second order correction for the nonlinear oscillator and in the corresponding relative error. The correct expressions are given here. The results of the paper are not changed, as we consider the nonlinearity up to first order perturbation theor

Aproximações entre a Psicologia de Vygotsky e a Filosofia para Crianças de Lipman: questões sobre aprendizagem e desenvolvimento

O presente artigo aborda algumas discussões sobre a aprendizagemcomo necessidade humanizadora criada com motivos e interesses do indivíduo,contribuindo para o seu desenvolvimento, tendo como referência a psicologiahistórico-cultural de Vygotsky e o pensamento de Lipman sobre aaprendizagem escolar. Ressaltamos que a relação do sujeito cognoscente como objeto de conhecimento ocorre por meio de interação que é mediada pordois elementos básicos: os instrumentos e os signos, ocorrendonecessariamente, por meio do processo de internalização

The dissipative quantum Duffing oscillator: a comparison of Floquet-based approaches

We study the dissipative quantum Duffing oscillator in the deep quantum regime with two different approaches: The first is based on the exact Floquet states of the linear oscillator and the nonlinearity is treated perturbatively. It well describes the nonlinear oscillator dynamics away from resonance. The second, in contrast, is applicable at and in the vicinity of a N-photon resonance and it exploits quasi-degenerate perturbation theory for the nonlinear oscillator in Floquet space. It is perturbative both in driving and nonlinearity. A combination of both approaches yields the possibility to cover the whole range of driving frequencies. As an example we discuss the dissipative dynamics of the Duffing oscillator near and at the one-photon resonance.Comment: 38 pages, 4 figure

Sensory-motor habit: preparing for intelligence and its implications for education

O presente artigo tem por objetivo destacar as principais ideias piagetianas a respeito do período sensório-motor e sua importância na elaboração e adaptação das funções e estruturas preliminares para o desenvolvimento da inteligência bem como suas implicações para a educação. A metodologia adotada pautou-se em um levantamento bibliográfico com autores que tratam dos tópicos mencionados acima e na interpretação das obras de Piaget sobre a construção do conhecimento no período sensório-motor compreendido entre o nascimento da criança até os 2 anos de vida. O hábito vai se constituir em inteligência quando se coordenar em meios e fins, visto que uma coisa é repetir indefinidamente uma manobra que teve êxito, e outra coisa é tentar apanhar um objeto numa nova situação. Por isso, a vida é construtora de formas, e o hábito é uma delas. A relação fundamental que envolve o desenvolvimento e a aprendizagem não é a relação de associação e, sim é de assimilação. Isto requer três aspectos a serem conhecidos pelo educador infantil: o conhecimento do sujeito epistemológico, das matérias a serem ensinadas e o processo de interação entre as crianças e as educadoras.Palavras-chave: hábito sensório-motor, conhecimento, educação. The main Piagetian ideas on the sensory-motor period and its importance in the elaboration and adaptation of the function and preliminary structures for the development of intelligence and its implications for education are provided. Methodology is foregrounded on a bibliographical survey on the topics mentioned above and on the interpretation of Piaget´s works on knowledge construction during the sensory-motor period, ranging from the child´s birth up to 2 years. Habit becomes intelligence when it coordinates itself into strategies and aims. The indefinite repetition of a successful action is different from when one tries to grab an object in a new situation. Life is a builder of forms and the habit is one of them. The basic relationship that comprises development and learning is not one of association but of assimilation. Therefore, three aspects should be known by children´s educators, namely, the knowledge of the epistemological subject, the subject-matter that should be taught, and the interaction process between children and educators.Key words: sensory-motor habit, knowledge, education

Atypical, non-standard functions of the microtubule associated Tau protein.

Since the discovery of the microtubule-associated protein Tau (MAPT) over 40 years ago, most studies have focused on Tau's role in microtubule stability and regulation, as well as on the neuropathological consequences of Tau hyperphosphorylation and aggregation in Alzheimer's disease (AD) brains. In recent years, however, research efforts identified new interaction partners and different sub-cellular localizations for Tau suggesting additional roles beyond its standard function as microtubule regulating protein. Moreover, despite the increasing research focus on AD over the last decades, Tau was only recently considered as a promising therapeutic target for the treatment and prevention of AD as well as for neurological pathologies beyond AD e.g. epilepsy, excitotoxicity, and environmental stress. This review will focus on atypical, non-standard roles of Tau on neuronal function and dysfunction in AD and other neurological pathologies providing novel insights about neuroplastic and neuropathological implications of Tau in both the central and the peripheral nervous system

Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes

We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress