Light Element Evolution and Cosmic Ray Energetics

Using cosmic-ray energetics as a discriminator, we investigate evolutionary models of LiBeB. We employ a Monte Carlo code which incorporates the delayed mixing into the ISM both of the synthesized Fe, due to its incorporation into high velocity dust grains, and of the cosmic-ray produced LiBeB, due to the transport of the cosmic rays. We normalize the LiBeB production to the integral energy imparted to cosmic rays per supernova. Models in which the cosmic rays are accelerated mainly out of the average ISM significantly under predict the measured Be abundance of the early Galaxy, the increase in [O/Fe] with decreasing [Fe/H] notwithstanding. We suggest that this increase could be due to the delayed mixing of the Fe. But, if the cosmic-ray metals are accelerated out of supernova ejecta enriched superbubbles, the measured Be abundances are consistent with a cosmic-ray acceleration efficiency that is in very good agreement with the current epoch data. We also find that neither the above cosmic-ray origin models nor a model employing low energy cosmic rays originating from the supernovae of only very massive progenitors can account for the $^6$Li data at values of [Fe/H] below $-$2.Comment: latex 19 pages, 2 tables, 10 eps figures, uses aastex.cls natbib.sty Submitted to the Astrophysical Journa

Time Discounting and Smoking Behavior Under Tax Hikes

By combining our broad panel survey of Japanese adults from 2005 to 2008 and actual cigarette tax data, we investigate how smoking behavior including responses to tax hikes depends on time discounting and its biases, such as hyperbolic discounting and the sign effect. Cigarette consumption displays significantly positive correlations with discount rates and the procrastinating tendency, and negative correlations with the sign effect. Hyperbolic, procrastinating, and naïve respondents decrease their after-tax-hike cigarette consumption more than the others, implying that, irrespective of the preannouncement of a future tax hike, they postpone smoking moderation until the tax hike actually takes place. Finally, the government's revenue from cigarette tax peaks at a JPY 29.92 (around USD 0.28 using the conversion rate [107.16] in February 2008) higher tax per cigarette than the present actual level

Analyzing the Decision to get Flu Shot: An Empirical Study

Influenza vaccination has been shown to be cost effective in reducing morbidity and mortality and in decreasing work absenteeism and use of health-care resources. The purpose of this study was to identify predictors and beliefs regarding people's vaccination decision against the influenza. It was hypothesized that Health Belief Model (HBM) categories, such as severity of illness, vaccine effectiveness and side effects of the vaccine, affect the decision to get flu shot. In addition, we examined psychological effects, such as time preference, subjective probability of flu, and attitude toward risk. A questionnaire surveys was conducted in the USA, in 2004. The questions included HBM categories and the psychological effects. The results indicate that the main predictors of past immunization against influenza are: the estimated effectiveness of the vaccination, periodic blood test, perceived severity of flu illness, side effects of vaccine (negative effect), having health anxieties, and subjective probability of being infected. Based upon these results, it is recommended to enlarging people's knowledge regarding the influenza illness, its potential risks, and the potential benefits of the vaccine

X-Rays from Accelerated Ion Interactions

We have developed in detail the theory of X-ray line and continuum production due to atomic interactions of accelerated ions, incorporating in our calculations information from a broad range of laboratory measurements. We applied our calculations to the Orion region from which nuclear gamma-ray lines were observed with the COMPTEL instrument on CGRO. The accelerated particles which produce this gamma-ray emission via nuclear reactions also produce X-ray lines via atomic interactions. We predict strong line emission in the range from 0.5 to 1 keV, mainly due to de-excitations in fast O ions. While much of the diffuse X-ray emission observed with ROSAT from Orion could be due to accelerated ions, the current X-ray data do not provide unambiguous signatures for such an origin. If future observations with high spectral resolution would confirm the predicted X-rays, the combined analysis of the X-ray and gamma-ray data will set important constraints on the origin of the accelerated particles and their interaction model.Comment: 26 pages, 14 figure

Human melanoma-initiating cells express neural crest nerve growth factor receptor CD271.

The question of whether tumorigenic cancer stem cells exist in human melanomas has arisen in the last few years. Here we show that in melanomas, tumour stem cells (MTSCs, for melanoma tumour stem cells) can be isolated prospectively as a highly enriched CD271(+) MTSC population using a process that maximizes viable cell transplantation. The tumours sampled in this study were taken from a broad spectrum of sites and stages. High-viability cells isolated by fluorescence-activated cell sorting and re-suspended in a matrigel vehicle were implanted into T-, B- and natural-killer-deficient Rag2(-/-)gammac(-/-) mice. The CD271(+) subset of cells was the tumour-initiating population in 90% (nine out of ten) of melanomas tested. Transplantation of isolated CD271(+) melanoma cells into engrafted human skin or bone in Rag2(-/-)gammac(-/-) mice resulted in melanoma; however, melanoma did not develop after transplantation of isolated CD271(-) cells. We also show that in mice, tumours derived from transplanted human CD271(+) melanoma cells were capable of metastatsis in vivo. CD271(+) melanoma cells lacked expression of TYR, MART1 and MAGE in 86%, 69% and 68% of melanoma patients, respectively, which helps to explain why T-cell therapies directed at these antigens usually result in only temporary tumour shrinkage

Smokers, Smoking Deprivation, and Time Discounting

This paper investigates whether smokers exhibit greater time discounting than non-smokers, and how short-term nicotine deprivation affects time discounting. A unique feature of our experiment is that our subjects receive rewards not only of money, but also of actual tobacco. This is done in order to elicit smokers' true preferences. Smokers are more impatient than non-smokers, consistent with previous studies. Additionally, nicotine deprivation makes smokers even more impatient. These results suggest that nicotine concentration has different effects on time preferences in the short and long runs