Direct observation of melting in a 2-D superconducting vortex lattice

Topological defects such as dislocations and disclinations are predicted to determine the twodimensional (2-D) melting transition. In 2-D superconducting vortex lattices, macroscopic measurements evidence melting close to the transition to the normal state. However, the direct observation at the scale of individual vortices of the melting sequence has never been performed. Here we provide step by step imaging through scanning tunneling spectroscopy of a 2-D system of vortices up to the melting transition in a focused-ion-beam nanodeposited W-based superconducting thin film. We show directly the transition into an isotropic liquid below the superconducting critical temperature. Before that, we find a hexatic phase, characterized by the appearance of free dislocations, and a smectic-like phase, possibly originated through partial disclination unbinding. These results represent a significant step in the understanding of melting of 2-D systems, with impact across several research fields, such as liquid crystal molecules, or lipids in membranes.Comment: Submitted to Nature Physic

Universality of Probability Distributions Among Two-Dimensional Turbulent Flows

We study statistical properties of two-dimensional turbulent flows. Three systems are considered: the Navier-Stokes equation, surface quasi-geostrophic flow, and a model equation for thermal convection in the Earth's mantle. Direct numerical simulations are used to determine 1-point fluctuation properties. Comparative study shows universality of probability density functions (PDFs) across different types of flow. Especially for the derivatives of the ``advected'' quantity, the shapes of the PDFs are the same for the three flows, once normalized by the average size of fluctuations. Theoretical models for the shape of PDFs are briefly discussed.Comment: 5 pages, 7 figure

Caracterização de amido de pinhão modificado com soluções de ácido clorídrico 0,1 e 0,2M em presença de etanol e metanol.

O amido de pinhão possui propriedades interessantes, porém pouco foi estudado até o momento. Proveniente do Sul do Brasil, a semente da Araucária angustifolia serve de alimento para diversas culturas da região. Os amidos nativos de diversas fontes botânicas possuem características de interesse industrial, porém algumas só são adquiridas ou melhoradas mediante a aplicação de agentes que modifiquem as estruturas originais dos grânulos, como ácidos e oxidantes. O presente trabalho teve como objetivo estudar propriedades do amido de pinhão nativo e este modificado, utilizando ácido clorídrico 0,1M e 0,2M, em meio etanólico e metanólico. Pelas curvas DSC foi possível determinar as temperaturas ?onset?, de pico e de conclusão do processo de gelatinização das amostras, além de se determinar a entalpia envolvida no processo. Pelas imagens NC-AFM pode-se medir o tamanho dos grânulos dos amidos e a rugosidade dos mesmos antes e após as modificações. Por meio da técnica TG-DTG, foi possível observar um perfil de perda de massa semelhante para todas as amostras, com 3 etapas definidas, sendo a 1ª referente à desidratação da amostra e a 2ª e 3ª referente à decomposição da matéria orgânica à cinzas. Através da análise de propriedade de pasta (RVA) se observou o perfil reológico das amostras, podendo determinar temperatura de pico, viscosidade final e retrogradação.CBRATEC

Análise térmica de diferentes amostras de amido de pinhão (Araucaria angustifolia) de diferentes regiões do sul do Brasil.

As sementes da Araucaria angustifolia, no Brasil conhecidas como ?pinhão? e são uma boa uma fonte de carboidratos complexos (100 gramas de semente contêm 36% de amido). Nesse estudo três amostras de pinhão, obtidas de diferentes regiões foram estudadas. As técnicas termoanalíticas DSC (em diferentes concentrações de água) e MEV foram usadas para caracterizar as amostras.Edição dos Anais do 7º Simpósio de Análise Térmica, 2015, Bauru

Neutrino nucleus cross sections

We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a $\Delta$- dominance model taking into account the renormalization of $\Delta$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.Comment: 9 pages, 6 figures, Presented at 4th DAE-BRNS Workshop on Hadron Physics, AMU, Aligarh, India, 18-23 Feb 200

Network e-Volution

Modern society is a network society permeated by information technology (IT). As a result of innovations in IT, enormous amounts of information can be communicated to a larger number of recipients faster than ever before. The evolution of networks is heavily influenced by the extensive use of IT, which has enabled co-evolving advanced quantitative and qualitative forms of networking. Although several networks have been formed with the aim to reduce or deal with uncertainty through faster and broader access to information, it is in fact IT that has created new kinds of uncertainty. For instance, although digital information integration in supply chains has made production planning more robust, it has at the same time intensified mutual dependencies, thereby actually increasing the level of uncertainty. The aim of this working paper is to investigate the aspects of evolving networks and uncertainty in networks at the cutting edges of different types of networks and from the perspective of different layers defining these networks