Habit and Heterogeneity in the Youthful Demand for Alcohol

Observed patterns of youthful drinking indicate substantial persistence. This paper analyzes how much of that persistence reflects the actual development of a habit, and how much is due to unobserved aspects of the individual and the environment. The role of restrictions on alcohol availability, both in the current period and in adolescence, is also explored. We find that much of the observed persistence represents habit formation, and not unobserved characteristics. Consequently, restrictions on availability, particularly at an early age, alter subsequent patterns of alcohol consumption and abuse.

Ablation of Martian glaciers

Glacier like landforms are observed in the fretted terrain of Mars in the latitude belts near + or - 42 deg. It was suggested that sublimation or accumulation-ablation rates could be estimated for these glaciers if their shapes were known. To this end, photoclinometric profiles were obtained of a number of these landforms. On the basis of analyses of these profiles, it was concluded that ice is chiefly ablating from these landforms that either are inactive rock-glaciers or have materials within them that are moving exceedingly slowly at this time. These conclusions are consistent with other geologic information. The analyses were performed using a two-dimensional model of an isothermal glacier

The Escape of Ionizing Photons from the Galaxy

The Magellanic Stream and several high velocity clouds have now been detected in optical line emission. The observed emission measures and kinematics are most plausibly explained by photoionization due to hot, young stars in the Galactic disk. The highly favorable orientation of the Stream allows an unambiguous determination of the fraction of ionizing photons, F_esc, which escape the disk. We have modelled the production and transport of ionizing photons through an opaque interstellar medium. Normalization to the Stream detections requires F_esc = 6%, in reasonable agreement with the flux required to ionize the Reynolds layer. Neither shock heating nor emission within a hot Galactic corona can be important in producing the observed H-alpha emission. If such a large escape fraction is typical of L_* galaxies, star-forming systems dominate the extragalactic ionizing background. Within the context of this model, both the three-dimensional orientation of the Stream and the distances to high-velocity clouds can be determined by sensitive H-alpha observations.Comment: 4 pages; LaTeX2e, emulateapj.sty, apjfonts.sty; 4 encapsulated PS figures. For correct labels, may need to print Fig. 3 separately due to psfig limitation. Astrophysical Journal (Letters), accepte

Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas

Simple, highly fluorinated receptors are shown to function as highly effective transmembrane anion antiporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for bicarbonate

Modular Forms and the Cosmological Constant

The vacuum amplitude of the heterotic string in a flat background vanishes for the first twenty orders of string perturbation theory. The proof relies on the algebraic geometry of modular forms

Local Exchange Services in the Next Century -- What Still Must Be Done to Bring Us to Where We Want to Be?

Our panel is Local Exchange Service in the Next Century--What Still must be Done to Bring Us to Where We Want to Be? We have four excellent panelists to address these questions. I expect the panelists to agree, in part, where we want to be, and they won\u27t spend a whole lot of time about increased service, new technology, lower prices, and all those things. I am sure we\u27ll hear some assurances along those lines, at least from three of the panelists. Most of the time will be spent on what still must be done to get us there. I hope we will have not just what we, the Commission, has to do to get us there, but also perhaps what they may have to do to get us there. Also, perhaps, some references to some new technologies

Evolutionary design and experimental validation of a flexible caudal fin for robotic fish

Designing a robotic fish is a challenging endeavor due to the non-linear dynamics of underwater environments. In this paper, we present an evolutionary computation approach for designing the caudal fin of a carangiform robotic fish. Evolutionary experiments are performed in a simulated environment utilizing a mathematical model to approximate the hydrodynamic motion of a flexible caudal fin. With this model, time-consuming computational fluid dynamic simulations can be avoided while maintaining a physically realistic simulation. Two approaches are employed to maximize a robotic fish’s average velocity. First, a hill-climbing algorithm is applied to find the optimal stiffness for a fixed shape caudal fin. Next, both fin stiffness and shape are simultaneously optimized with a genetic algorithm. Additionally, simulated caudal fins are compared to physically validated fins, which were fabricated with the aid of a 3D printer and tested on a robotic fish prototype. Results show a correlation between evolved results, model predicted behavior, and physical robot performance with some disparity due to the difficulty in accurately approximating real world performance in a simulation environment. Despite the disparity, evolutionary design is shown to be a viable process

Bosonization in Arbitrary Genus

The equivalence is proved between fermionic and scalar field theories on Riemann surfaces of arbitrary topology. The effects of global topology include a modification of the bosonic action

Alcohol

Excess drinking is associated with lost productivity, accidents, disability, early death, crime, neglect of family responsibilities, and personality deterioration. These and related concerns have justified special restrictions on alcoholic-beverage commerce and consumption. The nature and extent of government involvement in this arena vary widely over time and place, and are often controversial. Economists have contributed to the evaluation of alcohol policy through empirical work on the effects of alcohol-control measures on consumption and its consequences. Economics has also provided an accounting framework for defining and comparing costs and benefits of interventions, including excise taxes. Outside of the policy arena, economists have analyzed alcohol consumption in the context of stretching the standard model of consumer choice to include intertemporal effects and social influence. Nonetheless, perhaps the most important contribution by economists has been the repeated demonstration that there is nothing unusual about alcohol in at least one essential respect: consumers drink less ethanol (and have fewer alcohol-related problems) when alcohol-beverage prices are increased. Important econometric challenges remain, including the search for a satisfactory resolution to the conflicting results on the effect of price changes on consumption by consumers who tend to drunk heavily. There are also unresolved puzzles about the relationship between drinking and productivity; even after controlling for a variety of other characteristics, drinkers tend to have higher earnings than abstainers, and women's earnings (but not men's) tend to increase with alcohol consumption.