11,368 research outputs found
U.S. Farm Policy - At a Crossroads? The 2007 Farm Bill and the Doha Round
For only the second time in history a U.S. farm bill and a major trade negotiation are scheduled to conclude at essentially the same time, a little more than a year from now. American agriculture has much at stake in both, not only as to content but also as to how they mesh together. The fundamental purpose of farm legislation is to help producers manage risk, but our track record in doing that efficiently and effectively is at best mixed. Our traditional commodity programs have changed relatively little over the past 75 years, even though U.S. farm operations have changed dramatically. U.S. agriculture in 2005 hardly resembles production agriculture of the 1930s, when these programs began. And there are far more risk management mechanisms available from the private sector today than there were decades ago. Hence, it is time to consider updating our farm safety net, fitting it for 21st century agriculture, while gradually shifting the coverage of risk from the public sector (taxpayers) to the private sector. Our present safety net is complicated, costly to administer, and its benefits tilt heavily toward large producers and toward the producers of only five major commodities (wheat, corn, cotton, rice and soybeans). Those benefits are also rapidly capitalized into land values, often boosting the net worth of absentee landowners while also reducing our international competitiveness and making it extremely difficult for young people to start farming. In addition some aspects of our commodity programs may well be vulnerable to challenge under international rules. This suggests that a considered critique of our domestic policies is in order, and that we should re-design our policies to minimize or eliminate their shortcomings. Alternative risk management concepts, such as whole farm revenue insurance, clearly deserve consideration as this process unfolds. The Doha Round of trade negotiations can and should complement and support whatever domestic policy changes are in order. Domestic demand alone will never again support a vibrant, prosperous American agriculture. Our opportunities for market growth, particularly in commodities, lie outside the borders of the U.S. Those opportunities are primarily in developing countries whose per capita incomes are on the rise. Most of those countries are in Asia, and access to their markets should be our first priority in the Doha Round negotiations. If we succeed in that endeavor, adjustments in our domestic farm programs (many of which will be necessary no matter what happens in the Doha Round) will be much more palatable to U.S. farmers. There is one final piece to this policy puzzle, the opportunity to re-direct Federal financial resources to rural America in a way that can also ameliorate the adjustment in commodity programs that now seems inevitable. That can be done through a variety of programs that are not likely to run afoul of international rules, with benefits that can reach more rural residents than our present programs, and do so in a more equitable way. Included would be environmental programs that are already authorized and regularly oversubscribed; new environmental programs; a variety of energy generation possibilities; opportunities provided by biotechnology; tree planting for carbon fixation; industrial uses of farm products; and both hard and soft infrastructure investments. If we can skillfully couple this third grouping of activities with export market expansion we can have a healthy, viable American agricultural economy while simultaneously eliminating many, if not all, the shortcomings of our present agricultural policies. We will still have a safety net, but one that is re-designed to better serve U.S. farmers. Hopefully these new policies would be transitional in nature. Over time private sector risk management techniques should improve and become available to all farm enterprises in all areas of the country. Once that occurs our already sophisticated U.S. farmers should be able to handle their risk management challenges via private sector mechanisms rather than through taxpayer support.Agricultural and Food Policy,
LIBERALIZED AGRICULTURAL TRADE -- AT THE MULTILATERAL TRADE NEGOTIATIONS, BILATERALLY OR NOT AT ALL!
International Relations/Trade,
Consistency of Bayesian Linear Model Selection With a Growing Number of Parameters
Linear models with a growing number of parameters have been widely used in
modern statistics. One important problem about this kind of model is the
variable selection issue. Bayesian approaches, which provide a stochastic
search of informative variables, have gained popularity. In this paper, we will
study the asymptotic properties related to Bayesian model selection when the
model dimension is growing with the sample size . We consider
and provide sufficient conditions under which: (1) with large probability, the
posterior probability of the true model (from which samples are drawn)
uniformly dominates the posterior probability of any incorrect models; and (2)
with large probability, the posterior probability of the true model converges
to one. Both (1) and (2) guarantee that the true model will be selected under a
Bayesian framework. We also demonstrate several situations when (1) holds but
(2) fails, which illustrates the difference between these two properties.
Simulated examples are provided to illustrate the main results
Analysis of binary spatial data by quasi-likelihood estimating equations
The goal of this paper is to describe the application of quasi-likelihood
estimating equations for spatially correlated binary data. In this paper, a
logistic function is used to model the marginal probability of binary responses
in terms of parameters of interest. With mild assumptions on the correlations,
the Leonov-Shiryaev formula combined with a comparison of characteristic
functions can be used to establish asymptotic normality for linear combinations
of the binary responses. The consistency and asymptotic normality for
quasi-likelihood estimates can then be derived. By modeling spatial correlation
with a variogram, we apply these asymptotic results to test independence of two
spatially correlated binary outcomes and illustrate the concepts with a
well-known example based on data from Lansing Woods. The comparison of
generalized estimating equations and the proposed approach is also discussed.Comment: Published at http://dx.doi.org/10.1214/009053605000000057 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
A Dynamically Adaptive Sparse Grid Method for Quasi-Optimal Interpolation of Multidimensional Analytic Functions
In this work we develop a dynamically adaptive sparse grids (SG) method for
quasi-optimal interpolation of multidimensional analytic functions defined over
a product of one dimensional bounded domains. The goal of such approach is to
construct an interpolant in space that corresponds to the "best -terms"
based on sharp a priori estimate of polynomial coefficients. In the past, SG
methods have been successful in achieving this, with a traditional construction
that relies on the solution to a Knapsack problem: only the most profitable
hierarchical surpluses are added to the SG. However, this approach requires
additional sharp estimates related to the size of the analytic region and the
norm of the interpolation operator, i.e., the Lebesgue constant. Instead, we
present an iterative SG procedure that adaptively refines an estimate of the
region and accounts for the effects of the Lebesgue constant. Our approach does
not require any a priori knowledge of the analyticity or operator norm, is
easily generalized to both affine and non-affine analytic functions, and can be
applied to sparse grids build from one dimensional rules with arbitrary growth
of the number of nodes. In several numerical examples, we utilize our
dynamically adaptive SG to interpolate quantities of interest related to the
solutions of parametrized elliptic and hyperbolic PDEs, and compare the
performance of our quasi-optimal interpolant to several alternative SG schemes
Canonical general relativity: Matter fields in a general linear frame
Building on the results of previous work, we demonstrate how matter fields
are incorporated into the general linear frame approach to general relativity.
When considering the Maxwell one-form field, we find that the system that leads
naturally to canonical vierbein general relativity has the extrinsic curvature
of the Cauchy surface represented by gravitational as well as non-gravitational
degrees of freedom. Nevertheless the metric compatibility conditions are
undisturbed, and this apparent derivative-coupling is seen to be an effect of
working with (possibly orthonormal) linear frames. The formalism is adapted to
consider a Dirac Fermion, where we find that a milder form of this apparent
derivative-coupling appears.Comment: 13 pages; uses AMS-latex style file
Role of the community matron in advance care planning and ‘do not attempt CPR’ decision-making: a qualitative study
The community matron (CM) is often the key worker caring for patients with chronic, life-limiting, long-term conditions, but these patients are not always recognised as palliative cases. This study explored the experiences of CMs with regard to advance care planning (ACP) and ‘do not attempt cardiopulmonary resuscitation’ (DNACPR) decision-making to understand whether or not they felt adequately prepared for this aspect of their role, and why. Qualitative data were generated from six CMs using a broad interpretive phenomenological approach. Face-to-face recorded interviews were analysed using template analysis. The study found that although participants faced complex ethical situations around ACP and DNACPR almost on a daily basis, none had received any formal training despite the emphasis on training in national and local guidelines. Participants often struggled to get their patients accepted on to the Gold Standards Framework. The research found variability and complexity of cases to be the main barriers to clear identification of the palliative phase
EFFECT OF RACCOON (PROCYON LOTOR) REDUCTION ON BLANDING’S TURTLE (EMYDOIDEA BLANDINGII) NEST SUCCESS
The Lake County Forest Preserve District has monitored a state-endangered Blanding’s Turtle (Emydoidea blandingii) population at two adjoining nature preserves along the Illinois–Wisconsin border since 2004. Prior to predator management, 92.3% of documented and unprotected natural Blanding’s Turtle nests (12 of 13) and 88% of monitored artificial nests have been at least partially depredated. The goal of this study was to determine the efficacy of subsidized Raccoon (Procyon lotor) removal efforts in increasing the nest success of Blanding’s Turtles. During April–May 2013 and 2014, we captured and euthanized 78 Raccoons from our 2 km2 study area. We estimated pre-removal abundance estimates using the Leslie depletion method; it appeared that we removed 83–89% of the Raccoons from the study area each year and pre-removal density estimates were 37.5% lower in 2014 than 2013. During the study period, we monitored 22 Blanding’s Turtle in situ unprotected nests. In 2013, one of seven (14%) Blanding’s Turtle nests was partially depredated and no nests were completely depredated, indicative of a successful impact of Raccoon removal on Blanding’s Turtle nest success. However in 2014, nine of 15 (60%) Blanding’s Turtle nests were depredated. Our results provide some evidence that removal of Raccoons may have increased Blanding’s Turtle nest success but other factors, such as a functional response of surviving Raccoons or depredation by other subsidized predators may be contributing to decreased nest success
Carbon isotopes in bulk carbonaceous chondrites
The chemical and physical processes involved in the formation of the solar system are examined. Primitive matter has been found on a microscopic scale in a variety of meteorites: fragments of small solar system bodies that were never part of a large planet. This primitive matter has, in most cases, been identified by the presence of anomalous abundances of some isotopes of the chemical elements. Of particular interest for carbon isotope studies are the primitive meteorites known as carbonaceous chondrites. Using a selective oxidation technique to sort out the carbon contained in different chemical forms (graphite, carbonates, and organic matter), four carbonaceous chondrites are analyzed. The presence of the (13) C-rich component was confirmed and additional carbon components with different, but characteristic, isotopic signatures were resolved
Oxygen isotope fractionation in Apollo 12 rocks and soils
Oxygen isotopic compositions and fractionations between coexisting minerals found in lunar samples from Apollo 11 and Apollo 12 flight
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