Universality of One-Dimensional Heat Conductivity

We show analytically that the heat conductivity of oscillator chains diverges with system size N as N^{1/3}, which is the same as for one-dimensional fluids. For long cylinders, we use the hydrodynamic equations for a crystal in one dimension. This is appropriate for stiff systems such as nanotubes, where the eventual crossover to a fluid only sets in at unrealistically large N. Despite the extra equation compared to a fluid, the scaling of the heat conductivity is unchanged. For strictly one-dimensional chains, we show that the dynamic equations are those of a fluid at all length scales even if the static order extends to very large N. The discrepancy between our results and numerical simulations on Fermi-Pasta-Ulam chains is discussed.Comment: 7 pages, 2 figure

Captura incidental de tartarugas-marinhas em currais-de-pesca no litoral do Piauí, Brasil.

CBO2010

The GNAQ in the haystack: intramedullary meningeal melanocytoma of intermediate grade at T9-10 in a 58-year-old woman

Meningeal melanocytomas are rare tumors. They are derived from leptomeningeal melanocytes and predominantly occur along the spine and the posterior fossa. Here, the authors report a case of intramedullary melanocytoma of intermediate grade in a 58-year-old female patient who was initially misdiagnosed with malignant melanoma until mutational analyses of a panel of genes associated with melanotic tumors led to reclassification

Restructured products from tilapia industry by products: the effects of tapioca starch and washing cycles.

The tilapia fileting industry generates large amounts of nutritionally significant waste material, and the recovery of this material is important. The manufacture of restructured products from mechanically recovered fish meat (MRFM) obtained from tilapia fileting allows the use of proteins of high biological value that would otherwise be discharged into the environment. The objective of this study was to evaluate the effect of washing cycles (either one cycle or five cycles) and of the addition of tapioca starch (20% vs. a no-starch control) on the characteristics of surimi obtained from MRFM produced by the tilapia industry and destined for use in restructured products. To evaluate the quality attributes of the product, the structure of a surimi protein matrix and its relationship to selected physicochemical parameters and morphological characteristics was assessed. Both the number of washing cycles and the starch addition were found to influence the moisture, protein and lipid content of the MRFM surimi. Higher whiteness was found after five washing cycles. Because the tapioca starch acted as a stabilizer, the fat globules were more stable and well distributed, and an emulsion with better properties resulted. A homogeneous network of fat globules linked to the protein matrix by a layer of tapioca starch was formed. Another advantage of this approach is that tapioca starch is gluten free. This property is important for specific groups in the population, e.g., celiac-intolerant consumers.Autoria na publicação: FABÍOLA HELENA FOGAÇA

Is the internet the right medium for a 'don't quit campaign'?

This paper examines the effectiveness of promoting post-16 education and training via Internet. It examines the differences between those who intend to continue the post-16 schooling and those who do not. The implication of the findings challenges the effectiveness of a 'don't quit campaign' which was to offer support and guidance on the choice of post 16 options. This study found that the campaign has done very little for those who decided not to continue post-16 education. Consequently, disadvantaged young people need constant support and resources to eliminate the disparities between different groups

"The dearest of our possessions": applying Floridi's information privacy concept in models of information behavior and information literacy

This conceptual paper argues for the value of an approach to privacy in the digital information environment informed by Luciano Floridi's philosophy of information and information ethics. This approach involves achieving informational privacy, through the features of anonymity and obscurity, through an optimal balance of ontological frictions. This approach may be used to modify models for information behavior and for information literacy, giving them a fuller and more effective coverage of privacy issues in the infosphere. For information behavior, the Information Seeking and Communication Model, and the Information Grounds conception, are most appropriate for this purpose. For information literacy, the metaliteracy model, using a modification a privacy literacy framework, is most suitable

Experimental Observation of Strong Exciton Effects in Graphene Nanoribbons

Graphene nanoribbons (GNRs) with atomically precise width and edge structures are a promising class of nanomaterials for optoelectronics, thanks to their semiconducting nature and high mobility of charge carriers. Understanding the fundamental static optical properties and ultrafast dynamics of charge carrier generation in GNRs is essential for optoelectronic applications. Combining THz spectroscopy and theoretical calculations, we report a strong exciton effect with binding energy up to 700 meV in liquid-phase-dispersed GNRs with a width of 1.7 nm and an optical bandgap of 1.6 eV, illustrating the intrinsically strong Coulomb interactions between photogenerated electrons and holes. By tracking the exciton dynamics, we reveal an ultrafast formation of excitons in GNRs with a long lifetime over 100 ps. Our results not only reveal fundamental aspects of excitons in GNRs (gigantic binding energy and ultrafast exciton formation etc.), but also highlight promising properties of GNRs for optoelectronic devices.Comment: 26 pages, 4 figures, 5 pages Supplementary Informatio