6,437 research outputs found
Growth and Equity Effects of Agricultural Marketing Efficiency Gains in India
Agriculture is the largest source of employment in India, and food accounts for about half of consumer expenditures. Moving agricultural products from the farm to consumers more efficiently could result in large gains to producers, consumers, and India’s overall economy. This analysis uses a computable general equilibrium model with agricultural commodity detail and households disaggregated by rural, urban, and income class to study the potential impacts of reforms that achieve efficiency gains in agricultural marketing and reduce agricultural input subsidies and import tariffs. More efficient agricultural marketing generates economywide gains in output and wages, raises agricultural producer prices, reduces consumer food prices, and increases private consumption, particularly by low-income households. These gains could help to offset some of the medium-term adjustment costs for some commodity markets and households associated with reducing agricultural subsidies and tariffs.India, agriculture, policy reform, marketing efficiency, tariffs, subsidies, households, computable general equilibrium model., Agricultural and Food Policy, Agricultural Finance, Crop Production/Industries, International Relations/Trade, Marketing,
Energy Balance in the Solar Transition Region. IV. Hydrogen and Helium Mass Flows With Diffusion
In this paper we have extended our previous modeling of energy balance in the
chromosphere-corona transition region to cases with particle and mass flows.
The cases considered here are quasi-steady, and satisfy the momentum and energy
balance equations in the transition region. We include in all equations the
flow velocity terms and neglect the partial derivatives with respect to time.
We present a complete and physically consistent formulation and method for
solving the non-LTE and energy balance equations in these situations, including
both particle diffusion and flows of H and He. Our results show quantitatively
how mass flows affect the ionization and radiative losses of H and He, thereby
affecting the structure and extent of the transition region. Also, our
computations show that the H and He line profiles are greatly affected by
flows. We find that line shifts are much less important than the changes in
line intensity and central reversal due to the effects of flows. In this paper
we use fixed conditions at the base of the transition region and in the
chromosphere because our intent is to show the physical effects of flows and
not to match any particular observations. However, we note that the profiles we
compute can explain the range of observed high spectral and spatial resolution
Lyman alpha profiles from the quiet Sun. We suggest that dedicated modeling of
specific sequences of observations based on physically consistent methods like
those presented here will substantially improve our understanding of the energy
balance in the chromosphere and corona.Comment: 50 pages + 20 figures; submitted to ApJ 9/10/01; a version with
higher resolution figures is available at http://cfa-www.harvard.edu/~avrett
Entropic force in black hole binaries and its Newtonian limits
We give an exact solution for the static force between two black holes at the
turning points in their binary motion. The results are derived by Gibbs'
principle and the Bekenstein-Hawking entropy applied to the apparent horizon
surfaces in time-symmetric initial data. New power laws are derived for the
entropy jump in mergers, while Newton's law is shown to derive from a new
adiabatic variational principle for the Hilbert action in the presence of
apparent horizon surfaces. In this approach, entropy is strictly monotonic such
that gravity is attractive for all separations including mergers, and the
Bekenstein entropy bound is satisfied also at arbitrarily large separations,
where gravity reduces to Newton's law. The latter is generalized to point
particles in the Newtonian limit by application of Gibbs' principle to
world-lines crossing light cones.Comment: Accepted for publication in Phys. Rev.
Dual Requirement for Yeast hnRNP Nab2p in mRNA poly(A) Tail Length Control and Nuclear Export
Recent studies of mRNA export factors have provided additional evidence for a mechanistic link between mRNA 3′‐end formation and nuclear export. Here, we identify Nab2p as a nuclear poly(A)‐binding protein required for both poly(A) tail length control and nuclear export of mRNA. Loss of NAB2 expression leads to hyperadenylation and nuclear accumulation of poly(A)+ RNA but, in contrast to mRNA export mutants, these defects can be uncoupled in a nab2 mutant strain. Previous studies have implicated the cytoplasmic poly(A) tail‐binding protein Pab1p in poly(A) tail length control during polyadenylation. Although cells are viable in the absence of NAB2 expression when PAB1 is overexpressed, Pab1p fails to resolve the nab2Δ hyperadenylation defect even when Pab1p is tagged with a nuclear localization sequence and targeted to the nucleus. These results indicate that Nab2p is essential for poly(A) tail length control in vivo, and we demonstrate that Nab2p activates polyadenylation, while inhibiting hyperadenylation, in the absence of Pab1p in vitro. We propose that Nab2p provides an important link between the termination of mRNA polyadenylation and nuclear export
The finite tiling problem is undecidable in the hyperbolic plane
In this paper, we consider the finite tiling problem which was proved
undecidable in the Euclidean plane by Jarkko Kari in 1994. Here, we prove that
the same problem for the hyperbolic plane is also undecidable
Temperature effects on dislocation core energies in silicon and germanium
Temperature effects on the energetics of the 90-degree partial dislocation in
silicon and germanium are investigated, using non-equilibrium methods to
estimate free energies, coupled with Monte Carlo simulations. Atomic
interactions are described by Tersoff and EDIP interatomic potentials. Our
results indicate that the vibrational entropy has the effect of increasing the
difference in free energy between the two possible reconstructions of the
90-degree partial, namely, the single-period and the double-period geometries.
This effect further increases the energetic stability of the double-period
reconstruction at high temperatures. The results also indicate that anharmonic
effects may play an important role in determining the structural properties of
these defects in the high-temperature regime.Comment: 8 pages in two-column physical-review format with six figure
Prospective, randomized, double-blind clinical trial about efficacy of homeopathic treatment in children with obstructive adenoid
AIM: the efficacy and security of homeopathic treatment was investigated on children with obstructive adenoid justifying an operation. STUDY DESIGN: Clinical prospective. MATERIAL AND METHOD: In a prospective, randomized, double-blind clinical trial included 40 children between the ages of 3 to 7 years old, 20 children were treated with homeopathic medication, based in the principle of similarity (Simillimum), and 20 children with placebo. All the children of the homeopathic group/ adenoid, were treated daily with Agraphis nutans 6 CH, Thuya 6 CH and Adenoid 21CH, and the patients of the placebo group received daily placebo medication. The duration of the study of each children was 4 months. The evaluation of the results was clinical, and it was made by questionnaire standard, clinical examination and direct flexible fiberoptic nasopharyngoscopy, in the first and last day of treatment. The criterion of selection was the adenoid that occuped more than 70% of the coanal space. RESULTS: From the group of 20 children treated with homeopathic treatment, 13 did not show any change on the size of adenoid after nasopharyngoscopy, and 7 children had their adenoid decreased; from another group of 20 children that have treated with placebo for 4 months, 11 did not show any change on the size of their adenoid, 4 had their adenoid decreased and 5 had their adenoid increased. The statistical analysis showed a not significant difference (P= 0,069). The clinical evaluation of the patients showed that from the group of 20 patients treated with homeopathy, 17 kept unchanging, with oral breathing and snoring, one patient got better, eliminating the snoring and two were cured, which mean that their oral breathing turned to nasal breathing without snoring. From the group of 20 patients treated with placebo, 17 kept unchanging, one eliminated the snoring and two were cured; and these differences were not statistically significant (P> 0,999). CONCLUSIONS: the homeopathic treatment was not efficient in the patients with obstructive adenoid, remaining it surgical indication in 85% of the children. The homeopathic remedies did not provoke adverse events in the children.OBJETIVO: Avaliar a eficácia e segurança do tratamento homeopático em crianças com adenóide obstrutiva, com indicação cirúrgica. FORMA DE ESTUDO: Clínico prospectivo. Material e método: Estudo prospectivo, duplo-cego, randomizado, em que foram incluídas 40 crianças com idade variando de 3 a 7 anos, 20 crianças foram tratadas com medicação homeopática individualizada (Simillimum), baseada no princípio da similitude e 20 crianças receberam placebo. Todas as crianças do grupo medicação homeopática foram medicadas diariamente com Agraphis nutans 6 CH, Thuya 6 CH e Adenóide 21CH; e as do grupo placebo receberam diariamente medicamentos sem o princípio ativo. A duração do estudo de cada paciente foi de 4 meses. A avaliação dos resultados foi clínica, por meio de questionário padrão, de exame otorrinolaringológico e nasofaringoscopia direta com fibroscópio flexível, no primeiro e no último dia de tratamento. Utilizou-se como critério de inclusão a adenóide que ocupou mais do que 70% da luz coanal. RESULTADOS: Das 20 crianças tratadas com medicamento homeopático, 13 não apresentaram alteração no tamanho da adenóide nos exames nasofaringoscópicos e 7 tiveram diminuição da adenóide; das 20 crianças que receberam placebo por 4 meses, 11 não apresentaram alterações no tamanho da adenóide, 4 tiveram diminuição da adenóide e 5 crianças tiveram aumento. Não houve diferença estatística significante entre os grupos (P= 0,069). Na avaliação clínica da evolução dos pacientes, dos 20 pacientes tratados com medicamento homeopático, 17 se mantiveram inalterados, com respiração oral e ronco, um paciente melhorou, ficando sem ronco e dois foram curados, isto é, a respiração alterou-se de oral para nasal e sem ronco. Dos 20 pacientes tratados com placebo, 17 pacientes se mantiveram inalterados, um paciente melhorou do ronco e dois foram curados, não tendo havido diferença estatística significante entre os grupos (P>0,999). CONCLUSÕES: O tratamento homeopático não foi eficaz nas crianças com adenóide obstrutiva, mantendo-se a indicação cirúrgica em 85% dos pacientes. O medicamento homeopático não provocou eventos adversos nas crianças.Instituto Brasileiro de Estudos Homeopáticos Faculdade de Ciências da Saúde de São PauloUniversidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM)Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL
First Gale Western Butte Capping-Unit Compositions, and Relationships to Earlier Units Along Curiosity's Traverse
The Curiosity rover has been traversing through the clay-bearing unit (Glen Torridon; GT), approaching Greenheugh pediment, a large, fan-shaped surface surrounding the mouth of Gediz Vallis on the lower slope of Mt. Sharp. The pediment unconformably overlies the underlying bedrock, and is hence younger than units of the Mt. Sharp group. Orbital imaging of the pediment has shown it to have a slightly lower albedo and higher thermal inertia than neighboring units, to be relatively retentive of craters (e.g., erosion resistant), and to exhibit curved bedforms suggestive of lithified eolian bedforms. No diagnostic spectral signature has been observed from orbit. Recent rover positions allowed remote imaging of the contact between Greenheugh pediment and the eroded Murray formation strata below it, showing that the pediment capping material is cross-bedded and relatively thin (1-3 m), and suggesting that the pediment may have been much larger at one time. As Curiosity approached the edge of the pediment, the team investigated two buttes named Central and Western. The latter butte contains dark capping material that initially looked similar to the pediment cap, but close inspection revealed important physical differences. Here we report on compositions from ChemCam of two float rocks that appear to have rolled down from the capping unit, and on potential relation-ships to other targets along the traverse of the rover
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