16,635 research outputs found
The Impact of Public and Private R&D on Farmers' Production Decisions: Econometric Evidence for Midwestern States, 1960-2004
The objective of this paper is to identify the impact of public and private agriculturalresearch on multi-output multi-input profit maximizing decisions of Midwestern farmers. The mainhypothesis is that investments in public and private R&D shift outward the supply curves for cropand livestock outputs and, in some cases, reduce the demand for inputs. The study uses stateaggregate data for eight Midwestern states over 1960-2004. The own-price elasticities of demand forall inputs are shown to be negative, being larger for agricultural chemicals and energy that for farmcapital services, labor and other materials. Additional public agricultural research increases thesupply of crop and livestock outputs but biases revenue shares toward crop output. Additionalprivate R&D as in adoption of GM corn varieties shifts outward the supply curves for crops andlivestock outputs but biases revenue shares towards crop output. In contrast, an increase in theadoption of GM soybean varieties increases livestock output and deceases crop output. Publicagricultural research reduces the demand for capital services and energy and increases the demandfor agricultural chemicals, other materials, and labor. An increase in the availability of GM soybeanvarieties increases the demand for capital services, agricultural chemicals and other materials andhas weak negative effects on the demand for labor and energy. GM corn variety adoption reducesthe demand for energy but other effects are quite small.Profit function; midwest agriculture; public research; technology; GMOs; multiple-inputs multiple output; crops
Laboratory Transferability of Optimally Shaped Laser Pulses for Quantum Control
Optimal control experiments can readily identify effective shaped laser
pulses, or "photonic reagents", that achieve a wide variety of objectives. For
many practical applications, an important criterion is that a particular
photonic reagent prescription still produce a good, if not optimal, target
objective yield when transferred to a different system or laboratory, {even if
the same shaped pulse profile cannot be reproduced exactly. As a specific
example, we assess the potential for transferring optimal photonic reagents for
the objective of optimizing a ratio of photoproduct ions from a family of
halomethanes through three related experiments.} First, applying the same set
of photonic reagents with systematically varying second- and third-order chirp
on both laser systems generated similar shapes of the associated control
landscape (i.e., relation between the objective yield and the variables
describing the photonic reagents). Second, optimal photonic reagents obtained
from the first laser system were found to still produce near optimal yields on
the second laser system. Third, transferring a collection of photonic reagents
optimized on the first laser system to the second laser system reproduced
systematic trends in photoproduct yields upon interaction with the homologous
chemical family. Despite inherent differences between the two systems,
successful and robust transfer of photonic reagents is demonstrated in the
above three circumstances. The ability to transfer photonic reagents from one
laser system to another is analogous to well-established utilitarian operating
procedures with traditional chemical reagents. The practical implications of
the present results for experimental quantum control are discussed
Mixed membership stochastic blockmodels
Observations consisting of measurements on relationships for pairs of objects
arise in many settings, such as protein interaction and gene regulatory
networks, collections of author-recipient email, and social networks. Analyzing
such data with probabilisic models can be delicate because the simple
exchangeability assumptions underlying many boilerplate models no longer hold.
In this paper, we describe a latent variable model of such data called the
mixed membership stochastic blockmodel. This model extends blockmodels for
relational data to ones which capture mixed membership latent relational
structure, thus providing an object-specific low-dimensional representation. We
develop a general variational inference algorithm for fast approximate
posterior inference. We explore applications to social and protein interaction
networks.Comment: 46 pages, 14 figures, 3 table
Controlled switching between paramagnetic and diamagnetic Meissner effect in Pb/Co nanocomposites
A hybrid system which consists of a superconducting (SC) Pb film (100 nm
thickness) containing 1 vol% single domain ferromagnetic (FM) Co
particles of mean-size 4.5 nm reveal unusual magnetic properties: (i) a
controlled switching between the usual diamagnetic and the unusual paramagnetic
Meissner effect in field cooling as well as in zero-field cooling experiments
(ii) amplification of the positive magnetization when the sample enters the SC
state below T. These experimental findings can be explained by the
formation of spontaneous vortices and the possible alignment of these vortices
due to the foregoing alignment of the Co particle FM moments by an external
magnetic field.Comment: 5 pages, 3 figure
Retardation Terms in The One-Gluon Exchange Potential
It is pointed out that the retardation terms given in the original
Fermi-Breit potential vanish in the center of mass frame. The retarded
one-gluon exchange potential is rederived in this paper from the
three-dimensional one-gluon exchange kernel which appears in the exact
three-dimensional relativistic equation for quark-antiquark bound states. The
retardation part of the potential given in the approximation of order
is shown to be different from those derived in the previous literature. This
part is off-shell and does no longer vanish in the center of mass frame
Multiscale Technicolor and the Zbb-bar Vertex
We estimate the correction to the Zbb-bar vertex arising from the exchanges
of the sideways extended technicolor (ETC) boson and the flavor-diagonal ETC
boson in the multiscale walking technicolor model. The obtained result is too
large to explain the present data. However, if we introduce a new self-
interaction for the top quark to induce the top quark condensate serving as the
origin of the large top quark mass, the corrected R_b=Gamma_b/Gamma_h can be
consistent with the recent LEP data. The corresponding correction to
R_c=Gamma_c/Gamma_h is shown to be negligibly small.Comment: 9-page LaTex fil
Bogoliubov Hamiltonian as Derivative of Dirac Hamiltonian via Braid Relation
In this paper we discuss a new type of 4-dimensional representation of the
braid group. The matrices of braid operations are constructed by q-deformation
of Hamiltonians. One is the Dirac Hamiltonian for free electron with mass m,
the other, which we find, is related to the Bogoliubov Hamiltonian for
quasiparticles in He-B with the same free energy and mass being m/2. In the
process, we choose the free q-deformation parameter as a special value in order
to be consistent with the anyon description for fractional quantum Hall effect
with .Comment: 3 pages, 5 figure
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