Chaos in one-dimensional lattices under intense laser fields

A model is investigated where a monochromatic, spatially homogeneous laser field interacts with an electron in a one-dimensional periodic lattice. The classical Hamiltonian is presented and the technique of stroboscopic maps is used to study the dynamical behavior of the model. The electron motion is found to be completely regular only for small field amplitudes, developing a larger chaotic region as the amplitude increases. The quantum counterpart of the classical Hamiltonian is derived. Exact numerical diagonalizations show the existence of universal, random-matrix fluctuations in the electronic energy bands dressed by the laser field. A detailed analysis of the classical phase space is compatible with the statistical spectral analysis of the quantum model. The application of this model to describe transport and optical absorption in semiconductor superlattices submitted to intense infrared laser radiation is proposed.Comment: 9 pages, RevTex 3.0, EPSF (6 figures), to appear in Europhys. J.

The multifrequency behaviour of the recurrent nova RS Ophiuchi

This review concentrates on the multifrequency behaviour of RS Ophiuchi and in particular during its latest outburst. Confirmation of the 1945 outburst, bipolar outflows and its possible fate as a Type Ia Supernova are discussed.Comment: 5 pages, 5 figures, in The Golden Age of Cataclysmic Variables and Related Objects, F. Giovannelli & L. Sabau-Graziati (eds.), Mem. SAIt. 83 N.2 (in press

Rationale, Design and Methods of Set the Rules : A Tailored Peer-to-Peer Health Information Intervention

Ensuring equitable access to health information is one strategy to promote health equity for underserved communities, especially for low-income African Americans (AAs). Childcare centers are one viable site to deliver health information to address this disparity. This paper describes the methods used in a community-based participatory research project with a childcare facility that aimed to reduce environmental tobacco smoke (ETS) exposure among low-income AA children. Through collaboration and multiple data collection methods, partners identified communication strategies to overcome informational barriers. These initial findings indicated a peer-to-peer health information intervention, entitled “Set the Rules”, as the best strategy to increase awareness. The goal of the intervention was to build knowledge in reducing the harms of ETS exposure. Twelve community members were trained as parent leaders for the “Set the Rules” workshops and conducted workshops with parents. Even though there were barriers interfacing with all centers, parents that attended the workshop (n = 32) found the peer-to-peer intervention novel and quite helpful and will share the information learned with others. This intervention suggests that a childcare setting is a relevant space to increase access to health information to optimize child health outcomes. More research is necessary to determine if this intervention has salience in other childcare settings and across racial/ethnic groups

Resin-supported iridium complex for low-temperature vanillin hydrogenation using formic acid in water

Biorefinery seeks to utilize biomass waste streams as a source of chemical precursors with which to feed the chemical industry. This goal seeks to replace petroleum as the main feedstock,} however this task requires the development of efficient catalysts capable of transforming substances derived from biomass into useful chemical products. In this study{,} we demonstrate that a highly-active iridium complex can be solid-supported and used as a low-temperature catalyst for both the decomposition of formic acid (FA) to produce hydrogen{,} and as a hydrogenation catalyst to produce vanillyl alcohol (VA) and 2-methoxy-4-methylphenol (MMP) from vanillin (V); a lignin-derived feedstock. These hydrogenation products are promising precursors for epoxy resins and thus demonstrate an approach for their production without the need for petroleum. In contrast to other catalysts that require temperatures exceeding 100 °C{,} here we accomplish this at a temperature of <50 °C in water under autogenous pressure. This approach provides an avenue towards biorefinery with lower energy demands{, which is central to the decentralization and broad implementation. We found that the high activity of the iridium complex transfers to the solid-support and is capable of accelerating the rate determining step; the decomposition of FA into hydrogen and carbon dioxide. The yield of both VA and MMP can be independently tuned depending on the temperature. The simplicity of this approach expands the utility of molecular metal complexes and provides new catalyst opportunities in biorefinery

In Vitro Effects of PTH (1-84) on Human Skeletal Muscle-Derived Satellite Cells

Parathyroid hormone (PTH) is a hormone secreted by the parathyroid glands. Despite its well-known characterized anabolic and catabolic actions on the skeleton, the in vitro effects of PTH on skeletal muscle cells are limited and generally performed on animal models. The aim of this study was to evaluate the effects of a short impulse of PTH (1-84) on the proliferation and the differentiation of skeletal muscle satellite cells isolated from human biopsies. The cells were exposed for 30 min to different concentrations of PTH (1-84), from 10−6 mol/L to 10−12 mol/L. ELISA was used to assay cAMP and the myosin heavy-chain (MHC) protein. The proliferation was assayed by BrdU and the differentiation by RealTime-qPCR. A statistical analysis was performed by ANOVA followed by Bonferroni’s test. No significant variations in cAMP and the proliferation were detected in the isolated cells treated with PTH. On the other hand, 10−7 mol/L PTH on differentiated myotubes has shown significant increases in cAMP (p ≤ 0.05), in the expression of myogenic differentiation genes (p ≤ 0.001), and in the MHC protein (p ≤ 0.01) vs. untreated controls. This work demonstrates for the first time the in vitro effects of PTH (1-84) on human skeletal muscle cells and it opens new fields of investigation in muscle pathophysiology

Concettualizzazione e contestualizzazione dei beni culturali archeologici

This report describes the observations made while developing a new methodology for historic surveys used for the re-contextualisation of archaeological finds. This particular methodology avails itself of both traditional historic surveys as well as the representation of knowledge through ontology. The methodology described here was developed in reference to specific cases of re-contextualisation of archaeological artefacts from Pompeii which are now in the National Archaeological Museum in Naples

Playing at Sevens: The Impulse Load and Movement Demands of Men’s Collegiate Rugby

Rugby sevens is a widely practiced sport that combines high-speed anaerobic activity with positional specific play and many body impacts. Despite its popularity and its intense physical demands on the body, many of these demands have not been fully explored. An investigation into the specifics of these physical demands can aid coaches and athletes in training and preparation for future matches. The purpose of this study was to quantify the Impulse Load and movement dynamics placed on American rugby players during competition. With this data, position specific information was compared to determine differences in physical demands. Fourteen male collegiate rugby sevens players were assigned a microsenor device and bioharness prior to testing. Time motion analysis data was collected using these microsenor devices. Acceleration data was used to calculate Impulse Load and GPS data was used to quantify total distance and distance in six speed zones. The devices were placed on each player, securely fastened around the chest, and worn for the duration of the warm-up and two competitive matches, for a period of 1 hour and 47 minutes. Players were monitored using 5Hz global positioning systems (GPS) and 100Hz triaxial accelerometers. Players were further analyzed and divided by playing position (forwards and backs). The contrasts in physical demands based on position can provide feedback to coaches on position-specific training.Faculty Advisor: Brandi Eveland-Sayer

Organizational learning and emotion: constructing collective meaning in support of strategic themes

Missing in the organizational learning literature is an integrative framework that reflects the emotional as well as the cognitive dynamics involved. Here, we take a step in this direction by focusing in depth over time (five years) on a selected organization which manufactures electronic equipment for the office industry. Drawing on personal construct theory, we define organizational learning as the collective re-construal of meaning in the direction of strategically significant themes. We suggest that emotions arise as members reflect on progress or lack of progress in achieving organizational learning. Our evidence suggests that invalidation – where organizational learning fails to correspond with expectations – gives rise to anxiety and frustration, while validation – where organizational learning is aligned with or exceeds expectations – evokes comfort or excitement. Our work aims to capture the key emotions involved as organizational learning proceeds