31,916 research outputs found
ESTIMATES OF POTENTIAL RETURNS FROM ADDED RESEARCH BUDGET FOR THE LAND GRANT UNIVERSITIES
This paper briefly reviews approaches that have been used to assess returns to U.S. agricultural research and explains the usefulness of benefit cost analysis in such evaluations. Benefit-cost analysis is applied to the Land Grant Universities federal budget requests for additional funds for corn and soybean research in the North Central region. Finally, the problems involved in applying a similar analysis to livestock and rural development research are discussedResearch and Development/Tech Change/Emerging Technologies,
AGRICULTURAL DEVELOPMENT PLANNING FOR AN AMERICAN INDIAN RESERVATION: THE CASE OF THE SISSETON-WAHPETON SIOUX TRIBE
Agricultural and Food Policy,
Magnetic Monopoles and Free Fractionally Charged States at Accelerators and in Cosmic Rays
Unified theories of strong, weak and electromagnetic interactions which have
electric charge quantization predict the existence of topologically stable
magnetic monopoles. Intermediate scale monopoles are comparable with detection
energies of cosmic ray monopoles at IceCube and other cosmic ray experiments.
Magnetic monopoles in some models can be significantly lighter and carry two,
three or possibly even higher quanta of the Dirac magnetic charge. They could
be light enough for their effects to be detected at the LHC either directly or
indirectly. An example based on a D-brane inspired (trinification) model with the monopole carrying three quanta of Dirac
magnetic charge is presented. These theories also predict the existence of
color singlet states with fractional electric charge which may be accessible at
the LHC.Comment: 18 pages, 2 figures, minor revisions, references adde
Castleman disease and lymphocytic interstitial pneumonia: a complex diagnostic and management challenge
No abstract available
Investigation of the large scale coherent structure in a jet and its relevance to jet noise
A study was conducted to determine the causes of aircraft noise in large jet aircraft. It was determined that jet noise varies strongly with velocity and that significant pure tones are generated by rotor-stator interaction in the jet engines. An objective method for deducing the large eddy structure in a large jet is described. The provisions of lighthill's theory are analyzed and applied to investigating the nature of jet noise. There is considerable evidence that a large scale coherent structure exists in a jet and that this structure can play a major role in sound radiation. Mathematical models are developed to define the parameters of orthogonal decomposition, finite extent velocity field, homogeneous fields, and periodic velocity fields
Effects of atomic short-range order on the properties of perovskite alloys in their morphotropic phase boundary
The effects of atomic short-range order on the properties of
Pb(Zr_{1-x}Ti_x)O_3 alloy in its morphotropic phase boundary (MPB) are
predicted by combining first-principles-based methods and annealing techniques.
Clustering is found to lead to a compositional expansion of this boundary,
while the association of unlike atoms yields a contraction of this region.
Atomic short-range order can thus drastically affect properties of perovskite
alloys in their MPB, by inducing phase transitions. Microscopic mechanisms
responsible for these effects are revealed and discussed.Comment: 4 pages, with 2 postscript figures embedded. Uses REVTEX4 and
graphicx macro
Food Quality in Producer-Grazer Models: A Generalized Analysis
Stoichiometric constraints play a role in the dynamics of natural
populations, but are not explicitly considered in most mathematical models.
Recent theoretical works suggest that these constraints can have a significant
impact and should not be neglected. However, it is not yet resolved how
stoichiometry should be integrated in population dynamical models, as different
modeling approaches are found to yield qualitatively different results. Here we
investigate a unifying framework that reveals the differences and commonalities
between previously proposed models for producer-grazer systems. Our analysis
reveals that stoichiometric constraints affect the dynamics mainly by
increasing the intraspecific competition between producers and by introducing a
variable biomass conversion efficiency. The intraspecific competition has a
strongly stabilizing effect on the system, whereas the variable conversion
efficiency resulting from a variable food quality is the main determinant for
the nature of the instability once destabilization occurs. Only if the food
quality is high an oscillatory instability, as in the classical paradox of
enrichment, can occur. While the generalized model reveals that the generic
insights remain valid in a large class of models, we show that other details
such as the specific sequence of bifurcations encountered in enrichment
scenarios can depend sensitively on assumptions made in modeling stoichiometric
constraints.Comment: Online appendixes include
A Simulation of Demand-Driven Dataflow: Translation from Lucid into MDC Language
Message Driven Computation (MDC) is a model of computation with which they have been experimenting at the Illinois Institute of Technology. The authors aim to prove the viability of MDC in practice for the expression of parallel algorithms and the implementation of functional and dataflow programming languages. In the paper they discuss their implementation of the Lucid programming language in MDC. The discussion presents a subset of Lucid which illustrates the principles of Lucid, Message Driven Computing, and the translation into and the interpretation of dataflow graphs
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