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,

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,

Maximal information component analysis: a novel non-linear network analysis method.

BackgroundNetwork construction and analysis algorithms provide scientists with the ability to sift through high-throughput biological outputs, such as transcription microarrays, for small groups of genes (modules) that are relevant for further research. Most of these algorithms ignore the important role of non-linear interactions in the data, and the ability for genes to operate in multiple functional groups at once, despite clear evidence for both of these phenomena in observed biological systems.ResultsWe have created a novel co-expression network analysis algorithm that incorporates both of these principles by combining the information-theoretic association measure of the maximal information coefficient (MIC) with an Interaction Component Model. We evaluate the performance of this approach on two datasets collected from a large panel of mice, one from macrophages and the other from liver by comparing the two measures based on a measure of module entropy, Gene Ontology (GO) enrichment, and scale-free topology (SFT) fit. Our algorithm outperforms a widely used co-expression analysis method, weighted gene co-expression network analysis (WGCNA), in the macrophage data, while returning comparable results in the liver dataset when using these criteria. We demonstrate that the macrophage data has more non-linear interactions than the liver dataset, which may explain the increased performance of our method, termed Maximal Information Component Analysis (MICA) in that case.ConclusionsIn making our network algorithm more accurately reflect known biological principles, we are able to generate modules with improved relevance, particularly in networks with confounding factors such as gene by environment interactions

Social practices in the public space. Uses beyond social norms and the design of space.

En este artículo pretendemos describir las prácticas sociales y urbanas de las personas en un espacio público, concretamente en la ciudad de Barcelona. Las personas, cuando usan el espacio público lo transforman en lugar, es decir, generan ciertas relaciones y vínculos entre ellas y el espacio urbano, de tal forma que éste se modifica paulatinamente. Para la descripción de esas prácticas sociales y urbanas utilizamos una metodología cualitativa, específicamente una etnografía. Se identificaron y se eligieron tres tipos básicos de prácticas asociadas al espacio urbano: un tipo de esas prácticas se relaciona con el concepto de trabajo, otro con la idea de transitar (movimiento) y el último tipo con la práctica turística. Dichas prácticas sociales y urbanas evidenciaron el uso que llega a hacerse de los espacios públicos, uso que, la mayoría de las veces, es distinto al concebido en su diseño, bien por cuestiones estéticas o debido a las normas de uso. Las prácticas sociales descritas se relacionan con procesos psicosociales tales como: la identidad, la cohesión social, las normas sociales y la movilidad. Así mismo, dichas prácticas tienen la peculiaridad de sobrepasar los lineamientos de las normas sociales y urbanas y las finalidades de las estructuras existentes en el espacio

Quantum effective force in an expanding infinite square-well potential and Bohmian perspective

The Schr\"{o}dinger equation is solved for the case of a particle confined to a small region of a box with infinite walls. If walls of the well are moved, then, due to an effective quantum nonlocal interaction with the boundary, even though the particle is nowhere near the walls, it will be affected. It is shown that this force apart from a minus sign is equal to the expectation value of the gradient of the quantum potential for vanishing at the walls boundary condition. Variation of this force with time is studied. A selection of Bohmian trajectories of the confined particle is also computed.Comment: 7 figures, Accepted by Physica Script

PRICE RELATIONSHIPS FOR MEXICAN FRESH TOMATOES IN U.S. AND MEXICAN TERMINAL MARKETS

Tomato trade between the U.S. and Mexico has grown significantly during the past decade, with significant implications for markets in both countries. This work examines how terminal market prices for Mexican fresh tomatoes are being affected by price dynamics in distant, integrated markets by analyzing reaction patterns to various innovation shocks. We conclude that a high interdependence in the price formation process between Mexican markets and Los Angeles, as well as among Mexican markets, exists.Crop Production/Industries, Demand and Price Analysis,

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,

New Measurements of Venus Winds with Ground-Based Doppler Velocimetry at CFHT

operations with observations from the ground using various techniques and spectral domains (Lellouch and Witasse, 2008). We present an analysis of Venus Doppler winds at cloud tops based on observations made at the Canada France Hawaii 3.6-m telescope (CFHT) with the ESPaDOnS visible spectrograph. These observations consisted of high-resolution spectra of Fraunhofer lines in the visible range (0.37-1.05 μm) to measure the winds at cloud tops using the Doppler shift of solar radiation scattered by cloud top particles in the observer's direction (Widemann et al., 2007, 2008). The observations were made during 19-20 February 2011 and were coordinated with Visual Monitoring Camera (VMC) observations by Venus Express. The complete optical spectrum was collected over 40 spectral orders at each point with 2-5 seconds exposures, at a resolution of about 80000. The observations included various points of the dayside hemisphere at a phase angle of 67°, between +10° and -60° latitude, in steps of 10° , and from +70° to -12° longitude relative to sub-Earth meridian in steps of 12°. The Doppler shift measured in scattered solar light on Venus dayside results from two instantaneous motions: (1) a motion between the Sun and Venus upper cloud particles; (2) a motion between the observer and Venus clouds. The measured Doppler shift, which results from these two terms combined, varies with the planetocentric longitude and latitude and is minimum at meridian ΦN = ΦSun - ΦEarth where the two components subtract to each other for a pure zonal regime. Due to the need for maintaining a stable velocity reference during the course of acquisition using high resolution spectroscopy, we measure relative Doppler shifts to ΦN. The main purpose of our work is to provide variable wind measurements with respect to the background atmosphere, complementary to simultaneous measurements made with the VMC camera onboard the Venus Express. We will present first results from this work, comparing with previous results by the CFHT/ESPaDOnS and VLT-UVES spectrographs (Machado et al., 2012), with Galileo fly-by measurements and with VEx nominal mission observations (Peralta et al., 2007, Luz et al., 2011). Acknowledgements: The authors acknowledge support from FCT through projects PTDC/CTE-AST/110702/2009 and PEst-OE/FIS/UI2751/2011. PM and TW also acknowledge support from the Observatoire de Paris. Lellouch, E., and Witasse, O., A coordinated campaign of Venus ground-based observations and Venus Express measurements, Planetary and Space Science 56 (2008) 1317-1319. Luz, D., et al., Venus's polar vortex reveals precessing circulation, Science 332 (2011) 577-580. Machado, P., Luz, D. Widemann, T., Lellouch, E., Witasse, O, Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry, Icarus, submitted. Peralta J., R. Hueso, A. Sánchez-Lavega, A reanalysis of Venus winds at two cloud levels from Galileo SSI images, Icarus 190 (2007) 469-477. Widemann, T., Lellouch, E., Donati, J.-F., 2008, Venus Doppler winds at Cloud Tops Observed with ESPaDOnS at CFHT, Planetary and Space Science, 56, 1320-1334

An Empirical Analysis of Market Integration and Efficiency for U.S. Fresh Tomato Markets

Fresh tomato trade between the United States and Mexico grew significantly during the 1990s. Moreover, major structural changes in U.S. produce marketing channels increase the complexity of conducting analyses to delineate the impact of liberalized trade. Following the work of Barrett, Li, and Bailey, this study implements a mixed distribution to examine spatial-price relationships between major shipping points and terminal markets for Mexican imported, and Florida and California tomatoes. Although markets are often efficiently integrated, results suggest strategic pricing and product shipments may exist and vary among terminal markets in Los Angeles, Boston, and Chicago.market integration, North American tomato trade, spatial analysis, tomato markets, Industrial Organization,