680 research outputs found

    Assessment measures for specific language impairment in Brazil: A systematic review

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    Specific Language Impairment (SLI) is defined as an unexpected failure in linguistic abilities during a child\u27s early years of development. Children with SLI do not present significant impairment in nonverbal intellectual outcomes and do not lack normal environmental exposure to language. Brazilian and worldwide researchers have sought to understand the cultural implications of SLI in the Brazilian Portuguese language. Standardized and validated measures must be used in empirical studies. The present study systematically reviewed the instruments used to assess linguistic abilities in quantitative SLI research in Brazil. Three databases were chosen: Medline, SciELO, and Google Scholar. From a total of 828 articles retrieved, only 10 met the inclusion criteria. Seven standardized assessment measures were identified. However, only two of these reported psychometric properties using adequate normative data. No normalized instrument measured the entire spectrum of linguistic abilities. We discuss the results from the perspective of SLI theories and evidence in Brazil and worldwide

    On Aharonov-Casher bound states

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    In this work bound states for the Aharonov-Casher problem are considered. According to Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the E\boldsymbol{\nabla}\cdot\mathbf{E} term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem.Comment: 11 pages, matches published versio

    Effects of clays on spin-spin relaxation: a route for non-invasive total clay content quantification

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    Clay minerals are important components of sandstone rocks, due to their significant role on petrophysical properties like porosity and permeability. These minerals have a particular impact on Nuclear Magnetic Resonance measurements since the iron contained on clays generates internal gradients which directly affect the transverse relaxation. Here, we apply a methodology recently developed to a set of 20 sandstones, with varying clay content and mineralogy, in order to estimate the total clay content by using the effect of internal gradients on transverse relaxation. Based on these measurements, we propose a geochemical rock typing from quantities determined by our measurements, namely the total clay content and porosity

    Compostos fenólicos e enzimas oxidativos da graviola (Annona muricata) durante a maturação.

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    O presente trabalho teve por objetivo avaliar as variações nos teores de compostos fenólicos e na atividade de enzimas oxidativas durante a maturação da graviola
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