21,597 research outputs found

    Determining the Impact of Food Price and Income Changes on Obesity

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    Despite the significant rise in obesity in the U.S., economic research on obesity is still in its infancy. This paper employs a microeconomic approach to investigate the effects of price and income changes on weight in an effort to determine how a high-calorie food tax, a low-calorie food subsidy, and/or an income changes affect body weight. Although raising the price of high-calorie food typically will likely lead to decreased demand for such goods; it is not clear that such an outcome will actually reduce weight. The model developed in this paper identifies conditions under which price and income changes are mostly likely to actually result in a weight loss. The model is easily implemented using data on own-and cross-price elasticities that are often readily available from extant literature. This is important because survey data that contain both economic information, such as food prices, and weight are extremely rare. Information on relationship between price and weight is critical in developing appropriate public policy and in determining when and where fat taxes, thin subsidies or income re-distribution will achieve the desired objective of reducing obesity.Health Economics and Policy,

    Differences in Dolphin Mortality Rates in Night and Day Sets for the U.S. Eastern Tropical Pacific Tuna Purse Seine Fishery

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    Because dolphins sometimes travel with yellowfin tuna, Thunnus albacares, in the eastern tropical Pacific (ETP), purse seiners use the dolphins to locate and capture tuna schools. During the process of setting the purse seine nets, dolphins often become entangled and drown before they can be released. Data for the U.S. purse seine fleet in the ETP during 1979-88 show that dolphin mortality rates in sets made during the night are higher than mortality rates in sets made during the day. Even with efforts to reduce nightset mortality rates through the use of high intensity floodlights, night set mortality rates remain higher. The data are also used to simulate a regulation on the fishery aimed at eliminating night sets and show that dolphin mortality rates would decrease

    The Relative Importance of Preferences for Country-of-Origin in China, France, Niger and the United States

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    Country-of-origin (COO) is an increasingly politicized credence attribute in the globalizing food system. While international policy development in this area is geographically far-reaching, the benefits of country-of-origin labels (COOL) to producers and consumers from countries in different locations and levels of economic development are not clear. Previous work investigates the importance of COO to consumers, but is typically limited in scope to consumers in one nation. In addition, little is known about the importance of COO information relative to other credence attributes, especially in non-meat food products. This study measures the benefits of COOL to an internationally diverse set of consumers (in developed and developing countries) and estimates their priority rank in policy development. The paper draws upon research in the management literature suggesting consumer information needs are not based on quality alone, but also relate to affective (emotional) and normative (social acceptance) needs. A conjoint experiment is conducted in China, France, Niger and the United States to elicit consumer preferences for COO information, organic production, and genetic modification. The results indicate COO information is not as important as genetically modified content information (France, the United States, and Niger) or organic production information (China). Findings reveal individuals with quality and food safety information needs place higher importance on genetically modified and organic food information than COO information.country-of-origin, genetic modification, organic, conjoint, onion, information, food policy, International Relations/Trade, Q13, Q18, Q17,

    A Multidimensional Homo Economicus: Cultural Dimensions of Economic Preferences in Four Countries

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    Previous work in experimental economics reveals specific differences in economic behavior, especially reciprocity and free-riding behavior, across cultures. We expand the possible pallet of cross-cultural behavioral differences that may exist. We hypothesize that different kinds of strategic interaction and individual decision-making behaviors differ across locations. The variety of experiments we use allow us to report multidimensional rather than just single dimensional differences in behavior across locations. In order to build a broad Homo Economicus we conducted economic experiments in four dissimilar locations: Hangzhou, China; Niamey, Niger; Grenoble, France; Manhattan, Kansas; and West Lafayette, Indiana. Each subject completed an ultimatum bargaining game experiment, Voluntary Contribution Mechanism experiment, time preference experiment, and risk preference experiment. Results indicate economic behavior is not independent of location. Location differences are greatest for strategic interaction behavior and less prevalent for individual decision-making behavior.Time preference, risk preference, voluntary contribution mechanism, Ultimatum bargaining game, cultural, China, France, Niger, Kansas, Indiana, US, Institutional and Behavioral Economics,

    Observation of Single Transits in Supercooled Monatomic Liquids

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    A transit is the motion of a system from one many-particle potential energy valley to another. We report the observation of transits in molecular dynamics (MD) calculations of supercooled liquid argon and sodium. Each transit is a correlated simultaneous shift in the equilibrium positions of a small local group of particles, as revealed in the fluctuating graphs of the particle coordinates versus time. This is the first reported direct observation of transit motion in a monatomic liquid in thermal equilibrium. We found transits involving 2 to 11 particles, having mean shift in equilibrium position on the order of 0.4 R_1 in argon and 0.25 R_1 in sodium, where R_1 is the nearest neighbor distance. The time it takes for a transit to occur is approximately one mean vibrational period, confirming that transits are fast.Comment: 19 pages, 8 figure

    Gravitational macrosegregation in binary Pb-Sn alloy ingots

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    A space shuttle experiment employing the General Purpose (Rocket) Furnace (GPF) in its isothermal mode of operation is manifested on MSL-3, circa 1989. The central aim of this experiment is to investigate the effect of reduced gravity levels on the segregation behavior in a slowly, and isothermally, cooled sample of a binary Pb-15 wt% Sn alloy. This experiment should be able to simulate, in a small laboratory sample, some aspects of the segragation phenomena occurring in large industrial ingots. Ground-based experiments conducted in the single-cavity simulator of the GPF, in support of the microgravity experiment are described in detail. The results of the MSFC experiments are compared with other related experiments conducted at Case Western Reserve University (CWRS), wherein the isothermal constraints were relaxed. The isothermally processed samples indicate a small and gradual increase in fraction eutectic, and a corresponding increase in tin content, from the bottom to the top of the ingot. The radial variations are minimal near the ingot bottom, but there are large radial variations in the top half. In the CWRU experiments, more severe segregations, including segregation defects known as freckles. Follow up experiments employing the GPF without the isothermal constraints, or other suitably modified space shuttle hardware are suggested

    Weed Control Research in South Dakota

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    Clean seed, proper seedbed preparation, good crop rotations, and sounds soil management practices are the most reliable procedures for the control of weeds. They will eliminate many annual weeds and prevent infestation by most perennial weeds. Chemicals have proved to be valuable supplements to these practices. However, too many people rely on 2,4-D and, at least partially, neglect the standard practices. Consequently, weeds resistant to 2,4-D are allowed to spread. Once weeds become established, special practices are needed to eliminate them. These practices include the use of special cultivation, competitive crops, and chemicals in addition to the old reliable methods already mentioned. One application of any one of the practices seldom eliminates all perennial weeds. Even though top growth is eliminated, new weeds come from the seeds in the soil. Some of these seeds remain viable for as long as 20 years and many years of diligent work are required to eliminate them. The major portion of this circular is devoted to a discussion of research results obtained in South Dakota and neighboring states. The discussion of special cultural and chemical practices in concerned primarily with the control and elimination of weed infestations. It does not dwell on practices needed to prevent reinfestation of areas on which weeds have been eliminated

    Control and Elimination of Thistles

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    Canada thistle (Ci.rsium arvense L.) and perennial sowthistle (Sonchus arvensis L. or S. ulignosus Bieb.) are deep-rooted perennials that spread by underground parts and by seed. All species emerge later in the spring and are less difficult to control or eliminate than leafy spurge, hoary cress, or Russian knapweed. They emerge about the same time as field bindweed. Prevention of seed production is more important for thistles than for most perennial weeds. Wind currents carry the seeds great distances. Thistles reduce crop yields. The amount of reduction depends on how thick they are. Two plants of Canada thistle per square yard reduced wheat yields 18%, and 19 plants per square yard decreased yields 36%. A heavy infestation of sow thistle caused a 69% reduction of oat yields. To control or eliminate these thistles, use intensive cultivation, soil sterilant chemicals, certain competitive crops, selective herbicides, or several combinations of cultivation, crops, and chemicals

    Weed Control in Field Crops

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    Clean, seed, proper seedbed preparation, good rotations, and sound soil management practices are prime requisites for controlling weeds in crops. They will eliminate many annual weeds and prevent infestation by most perennial weeds. Chemicals are valuable supplements to these practices. However, if we rely on 2,4-D or other chemicals, we at least partially neglect the standard practices. Consequently, weeds resistant to chemicals are allowed to spread. Once weeds become established, special practices are needed to eliminate them. These practices include the use of special cultivation, competitive crops, and chemicals in addition to the old reliable practices already mentioned. One application of any one method seldom eliminates all perennial weeds. Even though they are eliminated, new weeds come from seeds in the soil. Some of these seeds remain viable for as long as 20 years and many years of diligent work are required to eradicate them. Numerous tillage and chemical methods that will control weeds in crops are available. In fact, it is possible to eliminate some of the most persistent perennial noxious weeds while growing crops if the proper combination of crops, cultivation, and chemicals is used. For detailed information on the control or elimination of any of South Dakota\u27s noxious weeds, refer to the circular that discusses the specific weed. If chemicals are to be used in the weed program, it is important to remember that chemicals cause more damage to crops when applied at certain stages than at others. This is particularly true when rates of application required to control perennial weeds are used. If the most tolerant stage of the crop does not occur when the weeds are in the most susceptible stage of growth, there are two choices-risk injuring the crop to get good weed control or get poor weed control with less chance of injuring the crop. Good weed control usually pays off in the long run. The maximum rate of chemical application that can be used on crops without much risk of reducing the yield is discussed on the following pages. Many annual weeds are killed with lower rates; consequently, the rate of application will frequently be lower than the maximums mentioned. On the other hand, many perennials will require higher rates than the safe rates mentioned. As a result one may have to use a more tolerant crop or risk injuring the crop if he wishes to eliminate the weed

    Floral and Genetic Divergence Across Environmental Gradients is Moderated by Inter-Population Gene Flow in \u3ci\u3ePlatanthera dilatata\u3c/i\u3e (Orchidaceae)

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    Understanding how natural selection acts on intraspecific variation to bring about phenotypic divergence is critical to understanding processes of evolutionary diversification. The orchid family is well known for pollinator-mediated selection of floral phenotypes operating among species and along environmental or geographic gradients. Its effectiveness at small spatial scales is less understood, making the geographic scale at which intraspecific floral variation is examined important to evaluating causes of phenotypic divergence. In this study, we quantified phenotypic variation in the orchid Platanthera dilatata across 26 populations in coastal Southeast Alaska and compared this to edaphic and genetic variation at microsatellite loci. We sought to determine (1) if flower morphological variation is structured at smaller geographic scales, (2) the extent of genetic divergence in relation to phenotypic divergence, (3) the scale at which inter-population gene flow occurs, and (4) the relative importance of geographic distance and abiotic factors on population genetic structure. Two morphological groups were found to separate based on lip and spur length and are restricted to different habitats. Small-flowered forms occur in muskeg bogs, whereas large-flowered forms occur in fens and meadows, and rarely in sub-alpine habitat. Genetic analyses were concordant with the morphological clusters, except for four small-flowered populations that were genetically indistinguishable from large-flowered populations and considered to be introgressed. In fact, most populations exhibited some admixture, indicating incomplete reproductive isolation between the flower forms. Pollinators may partition phenotypes but also facilitate gene flow because short-tongued Noctuidae moths pollinate both phenotypes, but longer-tongued hawkmoths were only observed pollinating the large-flowered phenotype, which may strengthen phenotypic divergence. Nevertheless, pollinator movement between habitats could have lasting effects on neutral genetic variation. At this small spatial scale, population genetic structure is only associated with environmental distance, likely due to extensive seed and pollinator movement. While this study corroborates previous findings of cryptic genetic lineages and phenotypic divergence in P. dilatata, the small scale of examination provided greater understanding of the factors that may underlie divergence
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