Lithium abundance evolution in open clusters: Hyades, NGC752, and M67

Mixing mechanisms bring the Li from the base of the convective zone to deeper and warmer layers where it is destroyed. These mechanisms are investigated by comparing observations of Li abundances in stellar atmospheres to models of stellar evolution. Observations in open cluster are especially suitable for this comparison, since their age and metallicity are homogeneous among their members and better determined than in field stars. In this work, we compare the evolution of Li abundances in three different clusters: the Hyades, NGC752, and M67. Our models are calculated with microscopic diffusion and transport of chemicals by meridional circulation, and calibrated on the Sun. These comparisons allow us to follow the evolution of Li abundance as a function of stellar mass in each cluster and as a function of the age by comparing this evolution in each cluster. We evaluate the efficiency of the mixing mechanisms used in the models, and we try to identify the lacking mechanisms to reproduce the observed evolution of Li abundance.Comment: 6 pages, 4 figures, conference publication of "New advances in stellar physics: from microscopic to macroscopic processes

Studies of dielectric breakdown under pulsed power conditions

In an effort to develop transmission lines with higher energy storage capabilities for compact pulsed power applications, the electrical breakdown strength (BDS) of ceramic dielectrics, particularly titanium oxide and ceramic/epoxy composite materials, are being characterized and studied. Results of research to-date show that the dense titania ceramics with nanocrystalline grain size (~200 nm) exhibit significantly higher electrical BDS as compared to ceramics made using coarse grain (micron grain size) materials when tested under DC conditions. We have performed pulsed testing under similar electric field stresses and found comparable behavior. Furthering the research has led to find the electrical BDS of materials such as ceramic/epoxy composites. These materials seem to be more flexible, robust, and might have increased electrical BDS as compared to dense titania ceramics. The powders are available with nominal particle sizes of 50 nm to 400 nm. The crystalline ceramic powders have uniform spherical morphology, precise stoichiomtery, Ba to Ti ratio, and high ceramic purity. The effects of rise time and fall time of high voltage pulsed power on the breakdown of the ceramic/epoxy composite material will also be the focus of interest. The purpose of this study was to describe test results, review the statistics that are used to analyze the data, and relate the understanding to what has been accumulated in the literature to-date in the context of dielectric breakdown and electrical BDS in such types of materials

The effects and recommendations for gender interaction in physical education

The purpose of this project was to review effects of gender interaction in physical education that might contribute to student\u27s participation levels in different learning environments. The review of literature was used to examine the effects of physical education and it was found that most studies suggested a single gendered environment resulted in more class participation

Analysis of intermittency in submillimeter radio and hard x-ray data during the impulsive phase of a solar flare

We present an analysis of intermittent processes occurring during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and has so far only been analyzed for hard X-ray data. Since in a typical flare the same accelerated electron population is believed to produce both hard X-rays and gyrosynchrotron radiation, we compare the two time profiles by searching for intermittency signatures. For this, we define a cross-wavelet power spectrum, which is used to obtain the local intermittency measure, or LIMLIM. When greater than three, the square LIMLIM coefficients indicate a local intermittent process. The LIM2LIM2 coefficient distribution in time and scale helps to identify avalanche or cascade energy release processes. We find two different and well-separated intermittent behaviors in the submillimeter data: for scales greater than 20 s, a broad distribution during the rising and maximum phases of the emission seems to favor a cascade process; for scales below 1 s, short pulses centered on the peak time are representative of avalanches. When applying the same analysis to hard X-rays, we find that only the scales above 10 s produce a distribution related to a cascade energy fragmentation. Our results suggest that different acceleration mechanisms are responsible for tens of keV and MeV energy ranges of electrons

Economic Determinants of Driver's Behavior in Minas Gerais

The aim of the paper is to evaluate the behavior of drivers when they face a safe-traffic environment. Some studies suggest that the laws that demand auto makers to produce safer vehicles also stimulate their drivers to drive carelessly, since the cost of driving carefully decreases. Likewise, a safer traffic environment or less dangerous surroundings can stimulate drivers to drive more aggressively and less carefully. This study tries to test whether the undesirable behavior described by Peltzman (1975) is observed on the highways and roads of the State of Minas Gerais, Brazil. Estimates based on data found in the Brazilian Federal Road Police's accident report databank confirm drivers'' lack of attention in safer environments. The results suggest that careless behavior in traffic increases when safer conditions prevail.

Labor Law—Back Pay Computed According to Woolworth Formula Approved by Supreme Court

N. L. R. B. v. Seven-Up Bottling Co., 73 S. Ct. 287 (1953)