Boletín MOMENTO ECONÓMICO, año 2, núms. 25-26, Septiembre-Octubre 2012.

El regreso del Partido Revolucionario Institucional (PRI) a la Presidencia de la República, sin lugar a dudas, se trata de un cambio político que los expertos en la materia deberán precisar su magnitud e impacto; en cuanto a las expectativas del momento económico, el futuro inmediato y mediato de la economía mexicana, lo cual es materia de este Boletín (a principios de diciembre y antes de ser enviado el presupuesto) todavía es muy pronto para tener una evaluación completa y estricta, ya que se están planteando un conjunto de reformas con el objetivo de “mover al país”. En principio se habla de tres iniciativas (Reformas Educativa, de Telecomunicaciones y a la Ley Nacional de Responsabilidad Hacendaria y Deuda Pública para entidades federativas y municipios). Asimismo, se ha insistido en Reformas a PEMEX para su apertura a la inversión priva- da en refinación, petroquímica y transporte de hidrocarburos, además de la puesta en marcha de la Reforma Laboral, vigente a partir del pasado 1° de diciembre

Las relaciones verticales y el poder de negociación de los agricultores integrados en forma de cooperativa frente a los individuales

Relations among the agricultural sector, the food industry and the retail sector take many forms, making it difficult to draw up a sufficiently exhaustive analytic framework capable of being generalised to all food activities. The nature of these relations depends to a great measure on the bargaining power of each of the agents taking part. Hence, for example, organising farmers into co-operatives or other forms of association raises their bargaining power with the food industry and/or the retail sector. In this way, following a methodology integrating “filière” analysis and the Structure-Conduct-Results model for Industrial Organisation, an empirical study is carried out with the aim of determining if differences exist in the vertical relations and bargaining power of Tenerife potato farmers associated to co-operatives versus independent growers in the area. Research results show that farmers associated to co-operatives and their customers and suppliers enjoy greater stability due to the existence of written contracts, though it is also true that they are dominated by oligopoly figures who supply and distribute the agricultural inputs and outputs, who are knowledgeable about the market and occur at the beginning and the end of the “filière”. Hence horizontal integration becomes a necessary strategy for the survival of the primary sector in Tenerife, with the aim of carrying out vertical integration enabling control of the product production and distribution chain.Agricultural system, Filière, Structure-Conduct-Results, Co-operative membership.

Mejoras en el sistema de control supervisorio de transferencia de custodia de la Refinería de Cartagena

La unidad operativa Departamento de Materias Primas y Productos de la Refinería de Cartagena, es la encargada de realizar las operaciones de entrega de combustible a las terminales de abastecimiento aledañas y a los buquetanques en la plataforma marina de ECOPETROL. Estos combustibles son conducidos a través de tuberías, desde los tanques de almacenamiento de producto terminado de la refinería, hasta la casabomba denominada Planta 21, donde son bombeados a través de líneas independientes hacia los diferentes destinos fuera de la refinería. A la salida de Planta 21 se encuentran unidades de medición fiscal, ubicados dentro del límite de batería de la refinería, que transmiten las señales de proceso; densidad, flujo, presión y temperatura, de los fluidos conducidos en las tuberías de despacho, a computadores de flujo ubicados en la Sala de Control de Recibos y Despachos, los cuales realizan la liquidación del volumen transferido y emiten el tiquete de facturación.Incluye bibliografía, anexo

Psychological model of ART adherence behaviors in persons living with HIV/AIDS in Mexico: a structural equation analysis

OBJECTIVE The objective of this study has been to test the ability of variables of a psychological model to predict antiretroviral therapy medication adherence behavior. METHODS We have conducted a cross-sectional study among 172 persons living with HIV/AIDS (PLWHA), who completed four self-administered assessments: 1) the Psychological Variables and Adherence Behaviors Questionnaire, 2) the Stress-Related Situation Scale to assess the variable of Personality, 3) The Zung Depression Scale, and 4) the Duke-UNC Functional Social Support Questionnaire. Structural equation modeling was used to construct a model to predict medication adherence behaviors. RESULTS Out of all the participants, 141 (82%) have been considered 100% adherent to antiretroviral therapy. Structural equation modeling has confirmed the direct effect that personality (decision-making and tolerance of frustration) has on motives to behave, or act accordingly, which was in turn directly related to medication adherence behaviors. In addition, these behaviors have had a direct and significant effect on viral load, as well as an indirect effect on CD4 cell count. The final model demonstrates the congruence between theory and data (x2/df. = 1.480, goodness of fit index = 0.97, adjusted goodness of fit index = 0.94, comparative fit index = 0.98, root mean square error of approximation = 0.05), accounting for 55.7% of the variance. CONCLUSIONS The results of this study support our theoretical model as a conceptual framework for the prediction of medication adherence behaviors in persons living with HIV/AIDS. Implications for designing, implementing, and evaluating intervention programs based on the model are to be discussed

Abnormal Maternal Body Mass Index and Customized Fetal Weight Charts : Improving the Identification of Small for Gestational Age Fetuses and Newborns

Background: Obesity and thinness are serious diseases, but cases with abnormal maternal weight have not been excluded from the calculations in the construction of customized fetal growth curves (CCs). Method: To determine if the new CCs, built excluding mothers with an abnormal weight, are better than standard CCs at identifying SGA. A total of 16,122 neonates were identified as SGA, LGA, or AGA, using the two models. Logistic regression and analysis of covariance were used to calculate the OR and CI for adverse outcomes by group. Gestational age was considered as a covariable. Results: The SGA rates by the new CCs and by the standard CCs were 11.8% and 9.7%, respectively. The SGA rate only by the new CCs was 18% and the SGA rate only by the standard CCs was 0.01%. Compared to AGA by both models, SGA by the new CCs had increased rates of cesarean section, (OR 1.53 (95% CI 1.19, 1.96)), prematurity (OR 2.84 (95% CI 2.09, 3.85)), NICU admission (OR 5.41 (95% CI 3.47, 8.43), and adverse outcomes (OR 1.76 (95% CI 1.06, 2.60). The strength of these associations decreased with gestational age. Conclusion: The use of the new CCs allowed for a more accurate identification of SGA at risk of adverse perinatal outcomes as compared to the standard CC

Conduits for myocardial revascularization grafts: the importance of morphology and imaging

The therapeutic options for patients with multivessel coronary artery disease, consist of pharmacological treatment, percutaneous coronary intervention and coronary artery bypass graft surgery. The ultimate goal of this surgery is to achieve complete revascularization with conduits that remain permeable for the remainder of the life of the patient. Some of the conduits used in this type of surgery, are the great saphenous vein, the internal thoracic artery, the radial artery and the ulnar artery. For a vascular conduit to be selected as a coronary revascularization graft, it must exhibit the following characteristics: sufficient length, lumen diameter and thickness of the vessel wall. It must also have minimal in situ ischemic consequences and an acceptable permeability over time of the conduit. Recent literatures of these conduits, as well as the importance of morphological and imaging studies are reviewed in this article

The evolution of paleo- and neo-endemic species of Cactaceae in the isolated Valley of Tehuacán-Cuicatlán, Mexico

Background and aims – Endemism may be defined according to the time of origin of taxa. Neo-endemics refer to relatively recent species that have not dispersed outside their ancestral areas. In contrast, paleo-endemics refer to species of ancient origins, which are currently geographically restricted but probably were more widespread in the past. Geographically, endemism areas may also be based on the co-occurrence of more than one species. We aimed to qualitatively identify the neo-endemism and paleo-endemism of endemic Cactaceae of the Tehuacán-Cuicatlán Valley, as well as to quantitatively assess paleo- and neo-endemics areas. Material and methods – Using a dated molecular phylogeny of endemic Cactaceae, we defined paleo- and neo-endemics using an arbitrary boundary of 2.6 million years ago; we also assessed the significance of concentrations of these species using a categorical analysis of paleo- and neo-endemism. Key results – Our results showed that most endemic Cactaceae in the Tehuacán-Cuicatlán Valley arose throughout the Pleistocene, while categorical analysis indicated localised mixed- and super-endemism (including both paleo- and neo-endemics) areas. Conclusion – We suggest that paleo- and neo-endemics, as well as localised mixed-endemism areas, may have originated due to a probable high climatic stability in the Tehuacán-Cuicatlán Valley, which in addition to topographically rugged and ecologically complex zones (e.g. ecotones, isolated habitat patches) may have allowed it to function as a refuge throughout Pleistocene climatic changes, mainly promoting the speciation of neo-endemics, as well as the persistence of relatively few paleo-endemics

Efecto antifúngico de hidrodestilados de Zingiber officinale Roscoe sobre Moniliophthora roreri (Cif&Par)

The frosty pod rot caused by the fungus Moniliophthora roreri (Cif. & Par) is the main disease of cocoa in Latin America, while the measures for their sustainable management are still limited. Based on previous reports the aim of this study, was to optimize the extraction process by the distillation of Zingiber officinale, and evaluating in vitro their antifungal effect on M. roreri, Eight hidrodestilleted were prepared with fresh material (300 and 600 g/L) and sun dried (45 and 90 g/L), with two solvents (Water:Alcohol ratio 10:1 and 10:0) for which the cultivation technique used, was test tubes in liquid medium (water extracted from cocoa) with conidia fungus. It was added each hidrodestillated of Z. officinale in ratio (1 :1 v/v), by which determines its effect on the formation and germination of the fungus conidia in five observation times (0, 24, 48, 72 and 96 hours).The results indicate that all hidrodestillators of the Z. officinale show metabolites with inhibitory effects on the variables evaluated, with thel5 (dried Z. officinale, 45 g/L ratio 10:1 water: alcohol) being the best treatment, due that it reaches from 88% to 100% control over the Conidias formation and germination respectively, with regard to the absolute witness at 72 hours, being also possible to optimize the distillation extraction by using 45 g/L dry material and employ solvent waterzalcohol in a 10:1 relationship.La moniliasis, ocasionada por el hongo Moniliophthora roreri (Cif. &amp, Par), es la principal enfermedad del cacao en Latinoamérica, y las medidas para su manejo sostenible son aún escasas. Con base en reportes previos, el objetivo de este trabajo fue optimizar el proceso de extracción por destilación de Zingiber officinale, evaluando in vitro su efecto antifúngico sobre conidias de M. roreri. Se elaboraron ocho hidrodestilados con material fresco (300 y 600 g/L) y seco al sol (45 y 90 g/L), con dos solventes (agua-alcohol, relación 10:1 y 10:0), y en tubos de ensayo con conidias del hongo, mediante la técnica de cultivo en medio líquido (agua-extracto de cacao), se adicionó cada hidrodestilado de Z. officinale en relación 1:1 v/v, determinando su efecto sobre la formación y germinación de conidias del hongo en cinco momentos de observación (0, 24, 48, 72 y 96 horas). Los resultados muestran que todos los hidrodestilados de Z. officinale presentan metabolitos con efectos de inhibición sobre las variables evaluadas, siendo el tratamiento J5 (Z. officinale seco, 45 g/L, relación 10:1 agua: alcohol) el mejor, pues alcanza el 88% y el 100% de control sobre la formación y germinación de conidias, respectivamente, con respecto al testigo absoluto a las 72 horas, siendo posible optimizar la extracción mediante destilación utilizando 45 g/L de material seco y el uso de solvente agua-alcohol en una relación 10:1

Estimation of the Evapotranspiration and Crop Coefficients of Bell Pepper Using a Removable Weighing Lysimeter: A Case Study in the Southeast of Spain

Water use efficiency is essential in semiarid regions of Spain, and it can be achieved through a precise knowledge of the real crop water requirements (CWR). The Food and Agriculture Organization of the United Nations (FAO) offers standardized crop coefficients to establish the CWR. However, these coefficients can change due to different conditions, such as climatic variations and cultivation practices. In this work, the evapotranspiration (ETClys) and crop coefficients (KClys) of bell pepper were obtained with a compact removable weighing lysimeter between February and August for two crop seasons (2019 and 2020). ETClys was determined from the water balance, and the KClys values were determined as the ratio of the crop evapotranspiration, measured on the removable weighing lysimeter, and the reference evapotranspiration. The KClys average values for the bell pepper in the initial, middle, and final stages were 0.57, 1.06, and 0.80, respectively. KC regression models were obtained as a function of the fraction thermal units, achieving a maximum correlation of 0.67 (R2). In general, the KC values obtained in this research work were lower in the initial and in the final stages and larger in the middle stage in comparison with the FAO-56 values and other research works values in semiarid conditions. The bell pepper yield increased by 7.72% in 2019 and by 3.49% in 2020 compared to the yield reported by the Ministry of the Environment and Rural and Marine Areas of the Spanish Government in 2019 and with a minimum water loss through drainage. The results in this work can help farmers to determine the crop water requirements and to improve the system efficiency in semiarid locations with similar conditions to those in the study

A Compact Weighing Lysimeter to Estimate the Water Infiltration Rate in Agricultural Soils

Infiltration estimation is made by tests such as concentric cylinders, which are prone to errors, such as the lateral movement under the ring. Several possibilities have been developed over the last decades to compensate these errors, which are based on physical, electronic, and mathematical principles. In this research, two approaches are proposed to measure the water infiltration rate in a silty loam soil by means of the mass values of a lysimeter weighing under rainfall conditions and different moisture contents. Based on the fact that with the lysimeter it is possible to determine acting soil flows very precisely, then with the help of mass conservation and assuming a downward vertical movement, 12 rain events were analyzed. In addition, it was possible to monitor the behavior of soil moisture and to establish the content at field capacity from the values of the weighing lysimeter, from which both approach are based. The infiltration rate of these events showed a variable rate at the beginning of the rainfall until reaching a maximum, to descend to a stable or basic rate. This basic infiltration rate was 1.49 ± 0.36 mm/h, and this is because soils with fine textures have reported low infiltration capacity. Four empirical or semi-empirical models of infiltration were calibrated with the values obtained with our approaches, showing a better fit with the Horton’s model