2,679 research outputs found
A Study of Iran’s Comparative Advantage in Saffron, the Red Gold
Crop Production/Industries, Environmental Economics and Policy,
An Analysis of Factors Determining Competitiveness: the Case of the Indonesian Palm Oil Industry
IndonesianKajian ini menganalisis faktor-faktor yang mempengaruhi daya saing industri kelapa sawit Indonesia di pasar Internasional. Kerangka kajian ini menggabungkan pendekatan teori perdagangan neo-klasik dan manajemen strategis dalam menganalisis daya saing Internasional pada tingkat industri. Penelitian ini menunjukan bahwa daya saing global industri kelapa sawit di Indonesia dapat dijelaskan oleh produktifitas tenaga kerja, nilai tukar rupiah, dan rasio konsentrasi empat Perusahaan. Campur tangan pemerintah dalam bentuk penentuan harga alokasi dalam negeri juga merupakan faktor yang sangat penting dan berpengaruh negatif pada daya saing global industri kelapa sawit di Indonesia.EnglishThis paper analyses factors that determine the competitiveness of the Indonesian palm oil industry including the effect of government interventions. The conceptual framework used in this study combines neo-classical trade and strategic management approaches for analyzing competitiveness at the industry level. This study shows that the competitiveness of the Indonesian palm oil industry can be explained by its labor productivity, the real exchange rates, and the four-firm concentration ratio. It is shown that government interventions--in the form of domestic allocation prices--have significant and negative effects on the competitiveness of the palm oil industry
Reconciling diverse lacustrine and terrestrial system response to penultimate deglacial warming in southern Europe
Unlike the most recent deglaciation, the regional expression of climate changes during the penultimate deglaciation remains understudied, even though it led into a period of excess warmth with estimates of global average temperature 1–2 °C, and sea level ∼6 m, above pre-industrial values. We present the first complete high-resolution southern European diatom record capturing the penultimate glacial-interglacial transition, from Lake Ioannina (northwest Greece). It forms part of a suite of proxies selected to assess the character and phase relationships of terrestrial and aquatic ecosystem response to rapid climate warming, and to resolve apparent conflicts in proxy evidence for regional paleohydrology. The diatom data suggest a complex penultimate deglaciation driven primarily by multiple oscillations in lake level, and provide firm evidence for the regional influence of abrupt changes in North Atlantic conditions. There is diachroneity in lake and terrestrial ecosystem response to warming at the onset of the last interglacial, with an abrupt increase in lake level occurring ∼2.7 k.y. prior to sustained forest expansion with peak precipitation. We identify the potentially important role of direct input of snow melt and glacial meltwater transfer to the subterranean karst system in response to warming, which would cause rising regional groundwater levels. This explanation, and the greater sensitivity of diatoms to subtle changes in temperature, reconciles the divergent lacustrine and terrestrial proxy evidence and highlights the sensitivity of lakes situated in mountainous karstic environments to past climate warming
On the master equation approach to kinetic theory: linear and nonlinear Fokker--Planck equations
We discuss the relationship between kinetic equations of the Fokker-Planck
type (two linear and one non-linear) and the Kolmogorov (a.k.a. master)
equations of certain N-body diffusion processes, in the context of Kac's
"propagation of chaos" limit. The linear Fokker-Planck equations are
well-known, but here they are derived as a limit N->infty of a simple linear
diffusion equation on (3N-C)-dimensional N-velocity spheres of radius sqrt(N)
(with C=1 or 4 depending on whether the system conserves energy only or energy
and momentum). In this case, a spectral gap separating the zero eigenvalue from
the positive spectrum of the Laplacian remains as N->infty,so that the
exponential approach to equilibrium of the master evolution is passed on to the
limiting Fokker-Planck evolution in R^3. The non-linear Fokker-Planck equation
is known as Landau's equation in the plasma physics literature. Its N-particle
master equation, originally introduced (in the 1950s) by Balescu and Prigogine
(BP), is studied here on the (3N-4)-dimensional N-velocity sphere. It is shown
that the BP master equation represents a superposition of diffusion processes
on certain two-dimensional sub-manifolds of R^{3N} determined by the
conservation laws for two-particle collisions. The initial value problem for
the BP master equation is proved to be well-posed and its solutions are shown
to decay exponentially fast to equilibrium. However, the first non-zero
eigenvalue of the BP operator is shown to vanish in the limit N->infty. This
indicates that the exponentially fast approach to equilibrium may not be passed
from the finite-N master equation on to Landau's nonlinear kinetic equation.Comment: 20 pages; based on talk at the 18th ICTT Conference. Some typos and a
few minor technical fixes. Modified title slightl
Second generation Robo-AO instruments and systems
The prototype Robo-AO system at the Palomar Observatory 1.5-m telescope is
the world's first fully automated laser adaptive optics instrument. Scientific
operations commenced in June 2012 and more than 12,000 observations have since
been performed at the ~0.12" visible-light diffraction limit. Two new infrared
cameras providing high-speed tip-tilt sensing and a 2' field-of-view will be
integrated in 2014. In addition to a Robo-AO clone for the 2-m IGO and the
natural guide star variant KAPAO at the 1-m Table Mountain telescope, a second
generation of facility-class Robo-AO systems are in development for the 2.2-m
University of Hawai'i and 3-m IRTF telescopes which will provide higher Strehl
ratios, sharper imaging, ~0.07", and correction to {\lambda} = 400 nm.Comment: 11 pages, 4 figures, 3 table
Divergences in the Effective Action for Acausal Spacetimes
The 1--loop effective Lagrangian for a massive scalar field on an arbitrary
causality violating spacetime is calculated using the methods of Euclidean
quantum field theory in curved spacetime. Fields of spin 1/2, spin 1 and
twisted field configurations are also considered. In general, we find that the
Lagrangian diverges to minus infinity at each of the nth polarised
hypersurfaces of the spacetime with a structure governed by a DeWitt-Schwinger
type expansion.Comment: 17 pages, Late
Ebola Virus Localization in the Macaque Reproductive Tract during Acute Ebola Virus Disease.
Sexual transmission of Ebola virus (EBOV) has been demonstrated more than a year after recovery from the acute phase of Ebola virus disease (EVD). The mechanisms underlying EBOV persistence and sexual transmission are not currently understood. Using the acute macaque model of EVD, we hypothesized EBOV would infect the reproductive tissues and sought to localize the infection in these tissues using immunohistochemistry and transmission electron microscopy. In four female and eight male macaques that succumbed to EVD between 6 and 9 days after EBOV challenge, we demonstrate widespread EBOV infection of the interstitial tissues and endothelium in the ovary, uterus, testis, seminal vesicle, epididymis, and prostate gland, with minimal associated tissue immune response or organ pathology. Given the widespread involvement of EBOV in the reproductive tracts of both male and female macaques, it is reasonable to surmise that our understanding of the mechanisms underlying sexual transmission of EVD and persistence of EBOV in immune-privileged sites would be facilitated by the development of a nonhuman primate model in which the macaques survived past the acute stage into convalescence
Population III star formation in a Lambda CDM universe, I: The effect of formation redshift and environment on protostellar accretion rate
(abridged) We perform 12 extremely high resolution adaptive mesh refinement
cosmological hydrodynamic simulations of Population III star formation in a
Lambda CDM universe, varying the box size and large-scale structure, to
understand systematic effects in the formation of primordial protostellar
cores. We find results that are qualitatively similar to those observed
previously. We observe that the threshold halo mass for formation of a
Population III protostar does not evolve significantly with time in the
redshift range studied (33 > z > 19) but exhibits substantial scatter due to
different halo assembly histories: Halos which assembled more slowly develop
cooling cores at lower mass than those that assemble more rapidly, in agreement
with Yoshida et al. (2003). We do, however, observe significant evolution in
the accretion rates of Population III protostars with redshift, with objects
that form later having higher maximum accretion rates, with a variation of two
orders of magnitude (10^-4 - 10^-2 Msolar/year). This can be explained by
considering the evolving virial properties of the halos with redshift and the
physics of molecular hydrogen formation at low densities. Our result implies
that the mass distribution of Population III stars inferred from their
accretion rates may be broader than previously thought, and may evolve with
redshift. Finally, we observe that our collapsing protostellar cloud cores do
not fragment, consistent with previous results, which suggests that Population
III stars which form in halos of mass 10^5 - 10^6 Msun always form in
isolation.Comment: Accepted by The Astrophysical Journal. Some minor changes. 65 pages,
3 tables, 21 figures (3 color). To appear in January 1, 2007 issu
Protein C Activity in Dogs: Adaptation of a Commercial Human Colorimetric Assay and Evaluation of Effects of Storage Time and Temperature
Objectives of this study were to adapt a commercial human protein C (PC) colorimetric assay for use in dogs and to investigate effects of various storage conditions. The human assay was modified by using pooled canine plasma for calibration and by increasing the activation time. PC activity was measured in fresh canine plasma and in plasma stored under various conditions. PC activity of some stored samples was significantly different from that of fresh plasma; however, differences were small. No difference was detected in samples stored under similar conditions but analyzed in different laboratories using similar methodology. Results of this study indicate that the human colorimetric assay is suitable for canine samples if pooled canine plasma is used for calibration, that Clinical and Laboratory Standards Institute sample storage guidelines developed for testing in humans are appropriate for dogs, and that comparisons of results from laboratories using similar methodology are legitimate
The Hartree limit of Born's ensemble for the ground state of a bosonic atom or ion
The non-relativistic bosonic ground state is studied for quantum N-body
systems with Coulomb interactions, modeling atoms or ions made of N "bosonic
point electrons" bound to an atomic point nucleus of Z "electron" charges,
treated in Born--Oppenheimer approximation. It is shown that the (negative)
ground state energy E(Z,N) yields the monotonically growing function (E(l N,N)
over N cubed). By adapting an argument of Hogreve, it is shown that its limit
as N to infinity for l > l* is governed by Hartree theory, with the rescaled
bosonic ground state wave function factoring into an infinite product of
identical one-body wave functions determined by the Hartree equation. The proof
resembles the construction of the thermodynamic mean-field limit of the
classical ensembles with thermodynamically unstable interactions, except that
here the ensemble is Born's, with the absolute square of the ground state wave
function as ensemble probability density function, with the Fisher information
functional in the variational principle for Born's ensemble playing the role of
the negative of the Gibbs entropy functional in the free-energy variational
principle for the classical petit-canonical configurational ensemble.Comment: Corrected version. Accepted for publication in Journal of
Mathematical Physic
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