Senioritis in repose

Media and other accounts of life after retirement suggest it to be “The Golden Years” of life, when the elderly have true leisure in the classic sense of freedom from responsibilities of work. However, like earlier time-diary studies, data from the 2003-07 Americans Time Use Project (ATUS) indicate that the great majority of seniors’ extra 20+ hours of free time is concentrated on three activities – TV, reading and rest. Only a few more hours are spent on sleep. Despite reports of increased work time among seniors, relatively few of those in Andy’s new age bracket remain in the labor force and they work fewer hours.Time use, elderly, retirement, free time, TV, aging

Sleep as a victim of the “time crunch” – A multinational analysis

As reflected in many popular and academic writings, there is general concern that contemporary life is becoming ruled by a societal “time crunch”, in which work and family pressures make daily life more hectic. One implica-tion of this condition is that sleep time has been reduced in order to accommodate these pressures. While this view seems supported by recent national surveys in which Americans now claim to get less than 7 hours of sleep a night, it is not supported by sleep times reported in 2003-07 ATUS time diaries. If anything, time-diary sleep hours are higher than in previous decades, approaching 60 hours a week in both the US and Canada. Similar levels of sleep hours are found in 18 European counties, with most of those having trend data also showing no decrease in sleep over recent decades, with the exceptions of Germany and Japan. The major predictors of sleep time in US and Canada are work hours and, increasingly, education. The US-Canada finding that women sleep slightly more than men is mainly a reflection of these two predictors. Higher sleep for women is also found in more Northern and Western European countries, but not in more Eastern and Southern Europe; moreover, men in Japan, the country with by far the least sleep report more diary hours of sleep than women.Sleep time, time-diary sleep hours, men, women

Simulation of Alternative Marketing Strategies for U.S. Cotton

Three marketing strategies (selling a put option, cash sale at harvest, and cash sale in June) are simulated based on historical values and ranked based on certainty equivalents for a representative irrigated and dryland cotton farm Scenario analysis is also used to compare varying yield values.Simulation, Marketing, Cotton, Risk, Marketing, Research Methods/ Statistical Methods,

SOCIAL IMPLICATIONS OF THE INTERNET

The Internet is a critically important research site for sociologists testing theories of technology diffusion and media effects, particularly because it is a medium uniquely capable of integrating modes of communication and forms of content. Current research tends to focus on the Internet’s implications in five domains: 1) inequality (the “digital divide”); 2) community and social capital; 3) political participation; 4) organizations and other economic institutions; and 5) cultural participation and cultural diversity. A recurrent theme across domains is that the Internet tends to complement rather than displace existing media and patterns of behavior. Thus in each domain, utopian claims and dystopic warnings based on extrapolations from technical possibilities have given way to more nuanced and circumscribed understandings of how Internet use adapts to existing patterns, permits certain innovations, and reinforces particular kinds of change. Moreover, in each domain the ultimate social implications of this new technology depend on economic, legal, and policy decisions that are shaping the Internet as it becomes institutionalized. Sociologists need to study the Internet more actively and, particularly, to synthesize research findings on individual user behavior with macroscopic analyses of institutional and political-economic factors that constrain that behavior.World Wide Web, communications, media, technology

Extinction hazards in experimental Daphnia magna populations: effects of genotype diversity and environmental variation

Extinction is ubiquitous in natural systems and the ultimate fate of all biological populations. However, the factors that contribute to population extinction are still poorly understood, particularly genetic diversity and composition. A laboratory experiment was conducted to examine the influences of environmental variation and genotype diversity on persistence in experimental Daphnia magna populations. Populations were initiated in two blocks with one, two, three, or six randomly selected and equally represented genotypes, fed and checked for extinction daily, and censused twice weekly over a period of 170 days. Our results show no evidence for an effect of the number of genotypes in a population on extinction hazard. Environmental variation had a strong effect on hazards in both experimental blocks, but the direction of the effect differed between blocks. In the first block, variable environments hastened extinction, while in the second block, hazards were reduced under variable food input. This occurred despite greater fluctuations in population size in variable environments in the second block of our experiment. Our results conflict with previous studies, where environmental variation consistently increased extinction risk. They are also at odds with previous studies in other systems that documented significant effects of genetic diversity on population persistence. We speculate that the lack of sexual reproduction, or the phenotypic similarity among our experimental lines, might underlie the lack of a significant effect of genotype diversity in our study

Planning tree windbreaks in Missouri

"Your need for a windbreak is measured by the benefits you can receive from one. Windbreak research has indicated that up to 40 percent heat energy savings are possible when you use windbreaks. Most of these savings result from reduced wind velocity and, therefore, in reduced air infiltration in homes downwind from the windbreak. (See Figure 1.) The properly placed windbreak also serves as an effective snow barrier and can improve the working conditions in farmstead areas where you perform winter chores. Crops protected from wind use moisture and nutrients more efficiently. Windbreaks reduce burning and wilting of crops often resulting from strong winds, high air temperatures and deficient moisture. However, because of tree root competition, crop yields will be less than normal in a strip about equal to the height of the trees. You can plant grass or legumes in these areas as roadways or turning areas. Crop yields generally decrease at distances about two to 10 times the tree height. In seasons of abundant moisture, cool temperatures and little wind, the windbreak is not likely to increase crop yields."--First page.John P. Slusher (School of Forestry, Fisheries and Wildlife), Jim Robinson (Soil Conservation Service, USDA) Clell Solomon (Missouri Department of Conservation)Revised 5/83/10

Core electrons and specific heat capacity in the fast electron heating of solids

The accuracy with which the Thomas–Fermi (TF) model can provide electronic specific heat capacities for use in calculations relevant to fast electron transport in laser-irradiated solids is examined. It is argued that the TF model, since it neglects the quantum shell structure, is likely to be significantly inaccurate for low- and intermediate-Z materials. This argument is supported by examining the results of calculations using more sophisticated methods that account for degeneracy, the quantum shell structure, and other non-ideal corrections. It is further shown that the specific heat capacity curve generated by this more advanced treatment leads to substantial (factor of two) changes in fast electron transport simulations relative to similar modelling based upon the TF model

The application of microwave heating in bioenergy: A review on the microwave pre-treatment and upgrading technologies for biomass

Bioenergy, derived from biomass and/or biological (or biomass-derived) waste residues, has been acknowledged as a sustainable and clean burning source of renewable energy with the potential to reduce our reliance on fossil fuels (such as oil and natural gas). However, many bioenergy processes require some form of pre-treatment and/or upgrading procedure for biomass to generate a modified residue with more suitable properties and render it more compatible with the specific energy conversion route chosen. Many of these pre-treatments (or upgrading procedures) involve some form of substantive heating of the biomass to achieve this modification. Microwave (MW) heating has attracted much attention in recent years due to the advantages associated with dielectric heating effects. These advantages include rapid and efficient heating in a controlled environment, increasing processing rates and substantially shortening reaction times by up to 80%. However, despite this interest, the growth of industrial MW heating applications for bioenergy production has been hindered by a lack of understanding of the fundamentals of the MW heating mechanism when applied to biomass and waste residues. This article presents a review of the current scientific literature associated with the application of microwave heating for both the pre-treatment and upgrading of various biomass feedstocks across different bioenergy conversion pathways including thermal and biochemical processes. The fundamentals behind microwave heating will be explained, as well as discussion of the imperative areas which require further research and development to bridge the gap between fundamental science in the laboratory and the successful application of this technology at a commercial scale

Quantum and classical surface acoustic wave induced magnetoresistance oscillations in a 2D electron gas

We study theoretically the geometrical and temporal commensurability oscillations induced in the resistivity of 2D electrons in a perpendicular magnetic field by surface acoustic waves (SAWs). We show that there is a positive anisotropic dynamical classical contribution and an isotropic non-equilibrium quantum contribution to the resistivity. We describe how the commensurability oscillations modulate the resonances in the SAW-induced resistivity at multiples of the cyclotron frequency. We study the effects of both short-range and long-range disorder on the resistivity corrections for both the classical and quantum non-equilibrium cases. We predict that the quantum correction will give rise to zero-resistance states with associated geometrical commensurability oscillations at large SAW amplitude for sufficiently large inelastic scattering times. These zero resistance states are qualitatively similar to those observed under microwave illumination, and their nature depends crucially on whether the disorder is short- or long-range. Finally, we discuss the implications of our results for current and future experiments on two dimensional electron gases.Comment: 16 pages, 8 figure