172 research outputs found
Pion-Muon Asymmetry Revisited
Long ago an unexpected and unexplainable phenomena was observed. The
distribution of muons from positive pion decay at rest was anisotropic with an
excess in the backward direction relative to the direction of the proton beam
from which the pions were created. Although this effect was observed by several
different groups with pions produced by different means, the result was not
accepted by the physics community, because it is in direct conflict with a
large set of other experiments indicating that the pion is a pseudoscalar
particle. It is possible to satisfy both sets of experiments if helicity-zero
vector particles exist and the pion is such a particle. Helicity-zero vector
particles have direction but no net spin. For the neutral pion to be a vector
particle requires an additional modification to conventional theory as
discussed herein. An experiment is proposed which can prove that the asymmetry
in the distribution of muons from pion decay is a genuine physical effect
because the asymmetry can be modified in a controllable manner. A positive
result will also prove that the pion is NOT a pseudoscalar particle.Comment: 9 pages, 3 figure
The Organization of Agricultural Research in Western Developed Countries
This paper reviews agricultural research structural and organization changes in western developed countries, examines new financing prospects for agricultural research, and provides some tentative conclusions about which organizations are best positioned to provide services for the 21st century. Giventhat these countries faces many similar economic, political, scientific, andagroclimatic factors and fiscal issues, we canexpect a similar set of similar new developments thathave potentially important and widespread long-run implications. After three common developments are outlined, principles ofimpure public good financing are applied leading to the following agricultural science policy recommendations (i) new political jurisdictions should be formed to finance research, e.g., new alliances across countries and subregions within large countries, (ii) intellecmal property rights should be strengthened to increase the total amount and share oftotal (public and private) agricultural research that is privately financed and conducted, i.e., the private sector should find it profitable to undertake a large share ofapplied research but not be expected to finance public sector agriculmral research, (iii) the public sector should redirect its research efforts increasingly to areas that are socially worthwhile but not privately undertaken, e.g.,in the basic and pretechnology areas, on envkonmental, resources, food safety and human nutrition, and policy. Finally, large countries that have developed asystem ofshared public and private financmg and performance and decentralized public support ofagricultural research seem best position for meeting the needs ofthe 21st centur
Economic Issues in Tariffication: An Overview
Tariffication is an effort to convert all existing agricultural nontariff barriers (NTBs) to trade into bound tariffs and to reduce these tariffs over time. The main economic issues that arise with tariffication stem from the nonequivalence of tariffs in NTBs in a number of scenarios. This paper analyzes nonequivalence arising from the existence of imperfect competition in importing countries, price instability in importing and exporting countries, and inefficient allocation of quantitative restrictions. It is shown that in all these cases the definition of an appropriate equivalent tariff to be used in tariffication is not straightforward, and that in general this equivalent tariff cannot be computed on the basis of only observed price differences between countries
Charged Majoron Emission in Neutrinoless Double Beta Decay
We examine in detail the predictions of the charged majoron model, introduced
recently by Burgess and Cline, for 0+ --> 0+ double beta decay transitions. The
relevant nuclear matrix elements are evaluated, within the quasiparticle random
phase approximation, for 76Ge, 82Se, 100Mo, 128Te and 150Nd nuclei. The
calculated transition rates turn out to be much smaller than the experimental
upper limits on possible majoron emission, except in a small region of the
model's parameter space.Comment: 9 pages, 1 encapsulated postscript figure, uses epsf.tex; reference
[15] has been correcte
Attentive Learning of Sequential Handwriting Movements: A Neural Network Model
Defense Advanced research Projects Agency and the Office of Naval Research (N00014-95-1-0409, N00014-92-J-1309); National Science Foundation (IRI-97-20333); National Institutes of Health (I-R29-DC02952-01)
The aggregate economic benefits of the national cultivar trials for maize in South Africa with specific reference to the Highveld region
The South African maize sector has been revolutionised from a system of
production with low use of modern technologies to a leading maize producer in
the African continent. That transformation is in part attributable to South Africa’s
investment in the national maize cultivar trials, which have facilitated the adoption
and use of maize cultivars that are highly adapted to commercial farmer localities,
causing considerable gains in yields. The economic value of the public investment
in the trials remains unknown. This study uses experimental yields spanning 1977
- 2012 to attribute the influence of the national maize cultivar trials to maize yield
improvement on farmer localities in the Highveld region of South Africa. Using
attribution methods, the study estimates that 24.3 kg per hectare of extra maize
yields accrued to commercial maize producers because of the national maize trials.
The economic value of these investments was found to be R1.4billion (in 2012
currency values). The study estimates that South Africa received R37 of benefit for
every rand invested by the Agricultural Research Council (ARC) in the trials.http://www.tandfonline.com/loi/ragr202016-09-30hb201
Multiperspective analysis of erosion tolerance
Erosion tolerance is the most multidisciplinary field of soil erosion research. Scientists have shown lack in ability to adequately analyze the huge list of variables that influence soil loss tolerance definitions. For these the perspectives of erosion made by farmers, environmentalists, society and politicians have to be considered simultaneously. Partial and biased definitions of erosion tolerance may explain not only the polemic nature of the currently suggested values but also, in part, the nonadoption of the desired levels of erosion control. To move towards a solution, considerable changes would have to occur on how this topic is investigated, especially among scientists, who would have to change methods and strategies and extend the perspective of research out of the boundaries of the physical processes and the frontiers of the academy. A more effective integration and communication with the society and farmers, to learn about their perspective of erosion and a multidisciplinary approach, integrating soil, social, economic and environmental sciences are essential for improved erosion tolerance definitions. In the opinion of the authors, soil erosion research is not moving in this direction and a better understanding of erosion tolerance is not to be expected in the near future
Inclusive D* Production in Two-Photon Collisions at LEP
Inclusive D^{*+-} production in two-photon collisions is studied with the L3
detector at LEP, using 683 pb^{-1} of data collected at centre-of-mass energies
from 183 to 208 GeV. Differential cross sections are determined as functions of
the transverse momentum and pseudorapidity of the D^{*+-} mesons in the
kinematic region 1 GeV < P_T < 12 GeV and |eta| < 1.4. The cross sections
sigma(e^+e^- -> e^+e^-D^{*+-}X) in this kinematical region is measured and the
sigma(e^+e^- -> e^+e^- cc{bar}X) cross section is derived. The measurements are
compared with next-to-leading order perturbative QCD calculations
Considerations for determining research priorities: learning cycles and impact pathways
Agricultural researchers identify and apply new science, novel approaches and innovations that could generate research breakthroughs and improve impacts to support the development of the agricultural sector. During the past few decades, there has been an expansion of the research agenda along the entire research-fordevelopment continuum, with farm- and policy-level implications. The goals and objectives of research have broadened from primarily food production to include sustainable resource management, equity, gender, health, and environmental concern
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