MEXICAN-U.S. FRESH TOMATO TRADE: AN ANALYSIS OF VOLUME, PRICES AND TRANSACTION COSTS

Tomato trade between the U.S. and Mexico has grown significantly during the past decade. Although the tariff reductions accorded under NAFTA may explain part of his increase, there are other supply and demand factors that affect trade flows. This study develops a U.S.-Mexico tomato trade model, with special focus on the interdependence between trading costs and the volume of Mexican imports. As expected, the exchange rate is a significant determinant of trading costs, but the level of tariffs was insignificant in both the trading and tomato supply equations. The shipping point price level and volume of imports also appear to affect these costs. For the import supply and demand models, there appears to be a significant share of imports that rely on previous levels of imports, rather than the expected economic factors (prices, income, and producer price index). We conclude that the structure and performance of the tomato trading market is changing, and may be more influential than tariff reductions in explaining increased trade flows.Crop Production/Industries, International Relations/Trade,

Scalar Field Dark Matter: non-spherical collapse and late time behavior

We show the evolution of non-spherically symmetric balls of a self-gravitating scalar field in the Newtonian regime or equivalently an ideal self-gravitating condensed Bose gas. In order to do so, we use a finite differencing approximation of the Shcr\"odinger-Poisson (SP) system of equations with axial symmetry in cylindrical coordinates. Our results indicate: 1) that spherically symmetric ground state equilibrium configurations are stable against non-spherical perturbations and 2) that such configurations of the SP system are late-time attractors for non-spherically symmetric initial profiles of the scalar field, which is a generalization of such behavior for spherically symmetric initial profiles. Our system and the boundary conditions used, work as a model of scalar field dark matter collapse after the turnaround point. In such case, we have found that the scalar field overdensities tolerate non-spherical contributions to the profile of the initial fluctuation.Comment: 8 revtex pages, 10 eps figures. Accepted for publication in PR

Diffuse neutrino supernova background as a cosmological test

The future detection and measurement of the diffuse neutrino supernova background will shed light on the rate of supernovae events in the Universe, the star formation rate and the neutrino spectrum from each supernova. Little has been said about what those measurements will tell us about the expansion history of the universe. The purpose of this article is to show that the detection of the diffuse supernova neutrino background will be a complementary tool for the study and possible discrimination of cosmological models. In particular, we study three different cosmological models: the $\Lambda$ Cold Dark Matter model, the Logotropic universe and a bulk viscous matter-dominated universe. By fitting the free parameters of each model with the supernova Ia probe, we found that the predicted number of events computed with the best fit parameters for the $\Lambda$-Cold dark matter model and with the Logotropic model are the same, while a bulk viscous matter-dominated cosmological model predicts $\sim 3$ times more events. We show that the current limit set by Super-Kamiokande on the diffuse supernova neutrino background flux gives complementary constraints on the free parameters of a bulk viscous matter-dominated universe. Furthermore, this limit implies, within a $\Lambda$ Cold Dark Matter model, that the universe should be expanding with $H_0 > 21.5 ~\rm{Km/sec/Mpc}$ independently of the content of dark matter $\Omega_m$.Comment: 19 pages, 8 figure

Access to diagnosis and treatment of Chagas disease/infection in endemic and non-endemic countries in the XXI century.

In this article, Médicos Sin Fronteras (MSF) Spain faces the challenge of selecting, piecing together, and conveying in the clearest possible way, the main lessons learnt over the course of the last seven years in the world of medical care for Chagas disease. More than two thousand children under the age of 14 have been treated; the majority of whom come from rural Latin American areas with difficult access. It is based on these lessons learnt, through mistakes and successes, that MSF advocates that medical care for patients with Chagas disease be a reality, in a manner which is inclusive (not exclusive), integrated (with medical, psychological, social, and educational components), and in which the patient is actively followed. This must be a multi-disease approach with permanent quality controls in place based on primary health care (PHC). Rapid diagnostic tests and new medications should be available, as well as therapeutic plans and patient management (including side effects) with standardised flows for medical care for patients within PHC in relation to secondary and tertiary level, inclusive of epidemiological surveillance systems

Can we make a Finsler metric complete by a trivial projective change?

A trivial projective change of a Finsler metric $F$ is the Finsler metric $F + df$. I explain when it is possible to make a given Finsler metric both forward and backward complete by a trivial projective change. The problem actually came from lorentz geometry and mathematical relativity: it was observed that it is possible to understand the light-line geodesics of a (normalized, standard) stationary 4-dimensional space-time as geodesics of a certain Finsler Randers metric on a 3-dimensional manifold. The trivial projective change of the Finsler metric corresponds to the choice of another 3-dimensional slice, and the existence of a trivial projective change that is forward and backward complete is equivalent to the global hyperbolicity of the space-time.Comment: 11 pages, one figure, submitted to the proceedings of VI International Meeting on Lorentzian Geometry (Granada

J D Bernal: philosophy, politics and the science of science

This paper is an examination of the philosophical and political legacy of John Desmond Bernal. It addresses the evidence of an emerging consensus on Bernal based on the recent biography of Bernal by Andrew Brown and the reviews it has received. It takes issue with this view of Bernal, which tends to be admiring of his scientific contribution, bemused by his sexuality, condescending to his philosophy and hostile to his politics. This article is a critical defence of his philosophical and political position

J D Bernal: philosophy, politics and the science of science

This paper is an examination of the philosophical and political legacy of John Desmond Bernal. It addresses the evidence of an emerging consensus on Bernal based on the recent biography of Bernal by Andrew Brown and the reviews it has received. It takes issue with this view of Bernal, which tends to be admiring of his scientific contribution, bemused by his sexuality, condescending to his philosophy and hostile to his politics. This article is a critical defence of his philosophical and political position

TRADABILITY AND MARKET EQUILIBRIUM FOR U.S.-MEXICO FRESH TOMATOES

Tomato trade between the U.S. and Mexico has grown significantly during the past decade. This increased trade, together with major structural changes in US produce marketing channels, has increased the complexity of conducting analysis of market integration and equilibrium. This study implements an Extended Parity Bounds Model (EPBM), following the work of Barrett and Li, to examine fresh tomato trade relationships between major shipping points and terminal markets for Mexican imported and Florida and California tomatoes. Findings suggest that, although markets seem relatively integrated and efficient, there exist some potential for claims of inefficient or overly competitive behavior. As is expected, the more complex the marketing channels between producer and wholesaler (distance or international boundaries), the more likely that markets operate suboptimally.International Relations/Trade,

PRICE RELATIONSHIPS AMONG NORTH AMERICAN FRESH TOMATO MARKETS: A COMPARISON BETWEEN MEXICAN AND U.S. MARKETS

Tomato trade between the U.S. and Mexican has grown significantly during the past decade, and market structure suggests increased market integration. This study examines fresh tomato price relationships between two major North American shipping points (Sinaloa, and Florida) and several major terminal markets in the U.S. and Mexico to infer whether business strategies vary by supply region or the geography of consumer markets. The results show some evidence of inefficient pricing behavior among some markets, and suggest that Mexican shipping point prices are less integrated with Mexico's own terminal markets than the closest U.S. market, Los Angeles. Moreover, perfectly competitive price behavior is less likely in a terminal market (Chicago) where Sinaloa and Florida compete during winter months. These results are the basis of discussion on the role of strategic behavior and trade policy influence in these markets.International Relations/Trade,