59,398 research outputs found
Promoting Public Health In The Context Of The “Obesity Epidemic”: False Starts And Promising New Directions
In the battle to combat obesity rates in the United States, several misconceptions have dominated policy initiatives. We address those misconceptions, including the notion that restrictive diets lead to long-term weight loss, that stigmatizing obesity is an effective strategy for promoting weight reduction, and that weight and physical health should be considered synonymous with one another. In offering correctives to each of these points, we draw on psychological science to suggest new policies that could be enacted at both the local and national levels. Instead of policies that rely solely on individual willpower, which is susceptible to failure, we recommend those that make use of environmental changes to reduce the amount of willpower necessary to achieve healthy behavior. Ultimately, the most effective policies will promote health rather than any arbitrary level of weight
Polyharmonic and Related Kernels on Manifolds: Interpolation and Approximation
This article is devoted to developing a theory for effective kernel
interpolation and approximation in a general setting. For a wide class of
compact, connected Riemannian manifolds, including the important
cases of spheres and SO(3), we establish, using techniques involving
differential geometry and Lie groups, that the kernels obtained as fundamental
solutions of certain partial differential operators generate Lagrange functions
that are uniformly bounded and decay away from their center at an algebraic
rate, and in certain cases, an exponential rate. An immediate corollary is that
the corresponding Lebesgue constants for interpolation as well as for
minimization are uniformly bounded with a constant whose only dependence on the
set of data sites is reflected in the mesh ratio, which measures the uniformity
of the data. The kernels considered here include the restricted surface splines
on spheres, as well as surface splines for SO(3), both of which have elementary
closed-form representations that are computationally implementable. In addition
to obtaining bounded Lebesgue constants in this setting, we also establish a
"zeros lemma" for domains on compact Riemannian manifolds -- one that holds in
as much generality as the corresponding Euclidean zeros lemma (on Lipschitz
domains satisfying interior cone conditions) with constants that clearly
demonstrate the influence of the geometry of the boundary (via cone parameters)
as well as that of the Riemannian metric.Comment: Final manuscript. Contains a new zeros lemma for regions on compact
Riemannian manifolds with Lipschitz boundaries -- constants are in terms of
parameters from a cone condition. 2 figures. 41 page
Price Effects from an Anticipated Meatpacking Plant Opening and Unexpected Plant Closing
Livestock producers primarily, but policy makers also, have an interest in market effects from meatpacking plant closings and openings. This article presents results from a study to determine price impacts from an anticipated hog slaughtering plant opening and an unexpected fed cattle slaughtering plant closing. The estimated price effects for each plant event were modeled with price difference and partial adjustment models. The plant opening resulted in higher absolute and relative hog prices in the Provincial market where the plant was located. However, adverse price impacts from the fed cattle plant closing were less evident.buyer competition, fed cattle, hogs, livestock prices, market dynamics, meatpacking, Demand and Price Analysis,
A review and meta analysis of health state utility values in breast cancer
Background and purpose:
Health-related quality of life is an important issue in the treatment of breast cancer, and health-state utilities are essential for cost-utility analysis. This paper identifies and summarises published utilities for common health-related quality of life outcomes for breast cancer, considers the impact of variation in study designs used, and pools utilities for some breast cancer health states.
Data sources and study selection:
13 databases were searched using key words relating to breast cancer and utility measurement. Articles were included if specified empirical methods for deriving utility values were used and details of the method, including number of respondents, were given. Articles were excluded if values were based on expert opinion or were not unique.
Data extraction and synthesis:
The authors identified 49 articles which met their inclusion criteria, providing 476 unique utilities for breast cancer health states. Where possible, mean utility estimates were pooled using ordinary least squares with utilities clustered within study group and weighted by both number of respondents and inverse of the variance of each utility. Regressions included controls for disease state, utility assessment method and other features of study design.
Results:
Utility values found in the review are summarised for six categories: 1) screening related states, 2) preventative states, 3) adverse events in breast cancer and its treatment, 4) non-specific breast cancer, 5) metastatic breast cancer states and 6) early breast cancer states. Pooled utility values for the latter two categories are estimated, showing base state utility values of between 0.668 and 0.782 for early breast cancer and 0.721 and 0.806 metastatic breast cancer depending upon which model is used. Utilities were found to vary significantly by valuation method, and who conducted the valuation.
Conclusions:
A large number of utility values for breast cancer are available in the literature; the states that these refer to are often complex, making pooling of values problematic
Torsion pendulum measurements on viscoelastic materials during vacuum exposure
A torsional pendulum apparatus designed for testing in situ in vacuum, the dynamic mechanical properties of materials is described. The application of this apparatus to an experimental program to measure the effects of vacuum on the mechanical properties of two ablator materials (a foamed material and a filled elastomer) and a solid rocket propellant (a filled elastomer) is presented. Results from the program are discussed as to the effects of vacuum on the mechanical properties of these three materials. In addition, time-temperature-superposition, as a technique for accelerating vacuum induced changes in mechanical properties, is discussed with reference to the three materials tested in the subject program
Arecibo Observatory support of the US international cometary Explorer mission encounter at comet Giacobini-Zinner
The Arecibo Observatory in Puerto Rico participated in the support of the U.S. International Cometary Explorer (ICE) mission when the ICE spacecraft passed through the tail of comet Giacobini-Zinner on September 11, 1985. The Arecibo Observatory is a research facility of the National Astronomy and Ionosphere Center (NAIC) operated by Cornell University under contract to the National Science Foundation (NSF). Coverage of the encounter involved the use of the observatory's 305-m (1000-ft) radio reflector antenna and RF and data system equipment fabricated or modified specifically for support of the ICE mission. The successful implementation, testing, and operation of this temporary receive, record, and data relay capability resulted from a cooperative effort by personnel at the Arecibo Observatory, the Goddard Space Flight Center, and the Jet Propulsion Laboratory
CAPTIVE SUPPLY TRENDS AND IMPACTS SINCE THE ADVENT OF MANDATORY PRICE REPORTING
Captive supplies have been a contentious issue in the livestock industry for fifteen years and the subject of both theoretical and empirical research. In 2001, mandatory price reporting was implemented. One objective by its proponents was to increase the amount of information available on captive supplies. This paper examines data now available as a result of mandatory price reporting to determine what additional information is available compared to previously. Second, several models were specified and estimated to determine the impacts captive supplies had on fed cattle prices in the two years following implementation of mandatory price reporting. Models showed mixed results. There was a consistent negative effect on cash market prices from formula priced trades; generally a positive impact from negotiated trades and packer owned trades on cash market prices; and mixed but often a positive impact from forward contract trades on cash market prices.Livestock Production/Industries, Marketing,
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