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Background In Mexico, there is an ancestral custom about the knowledge of the medicinal use of plants. Bixa orellana L. is a plant species that represents one of the main crops used in traditional medicine in southeastern Mexico. Background studies on its biological properties have been conducted on accessions harvested in Conkal, Yucatan, Mexico. Objectives In this work, the idea was to perform a phytochemical analysis of methanolic extracts of B. orellana. Materials and Methods Phytochemical screening was performed on methanolic extracts of leaves and seeds from two accessions of B. orellana, as well as on their antioxidant and antiproliferative activities. Results The phytochemical screening of the methanolic extracts of the leaves revealed the presence of tannins, terpenes, and saponins. A higher total content of phenols and flavonoids in leaves was also found compared to seeds, which coincides with a higher antioxidant activity in leaves compared to seeds. Regarding antiproliferative activity, the seeds and leaves of accession 3 showed the best results. Conclusion Accession 3 has better bioactive properties and can be a candidate in the search for antiproliferative and antioxidant compounds; this is the first study that associates this plant with this activity and demonstrates the chemical differences that exist between the accessions of B. orellana.

Hypertension is a widespread condition that affects millions of people around the world and has a major impact in public health. The classic renin–angiotensin system is a complex system comprised of multiple peptides and pathways that have been the driver of drug development over the years to control hypertension. However, there are still patients whose hypertension is very difficult to control with current drugs and strategies, thus motivating further research in this field. In the past two decades, important discoveries have expanded our knowledge of this system and new pathways are emerging that are helping us understand the complex interaction taking place not only in the periphery, but also in the central nervous system where the renin–angiotensin system is also very active. A new arm, called the ACE2/Ang-(1-7)/Mas receptor axis, was shown to exert antihypertensive properties and serve as a counterbalance to the classic ACE/angiotensin II/AT1 receptor axis, in this way modulating or even counteracting the negative effects of angiotensin II in blood pressure regulation and water retention. Modulation of this new axis through ACE2 activation, ADAM17 regulation or AT1 receptor internalization are some of the novel avenues and challenges that have the potential to become a target for new drug research and development for the treatment of hypertension.

In the Mexican Transportation Institute, multiproduct truck traffic assignment models have been developed over the past 15 years to assess improvements to the infrastructure and the transborder transport services between Mexico and the United States. A basic input of those models is the multiproduct (by product type) origin–destination (O-D) matrix. A better prediction of flows from the assignment models is obtained if the O-D matrix input contains the flows from the origin states in Mexico, toward the border crossings, and from these to the destination states in the United States for the Mexican exports and vice versa for the Mexican imports. To obtain this matrix, the information of transborder crossings of the U.S. Bureau of Transportation Statistics (BTS) is combined with O-D information that has been gathered in Mexico for more than 15 years from field stations installed in different places of the Federal Road Network. A two-step procedure is used to combine the two previous sources (a) to escalate the Mexican flows so that what arrives at each border site (Mexican information) equals what leaves that border site toward each state of the United States (BTS Database 11) and (b) to use a gravitational procedure to distribute what arrives at the border sites for a certain product type (Mexican information) in what arrives at each state of the United States of that product type (BTS Database 9). A similar methodology has been applied for the imports from the United States.

A description is given of the efforts of the Mexican Transportation Institute (IMT) to develop a geographic information system (GIS)-based data management system for accidents on federal roads in the various states of Mexico with the purpose of achieving efficiency, reliability, and automation for handling and processing of such data. A description is also given of the use of the developed system for generating some relevant results. Some conclusions are derived. Although the former is shown only for the case of the state of Oaxaca, the procedure presented has been completed for the other states of Mexico. For development of this work, the Arc View GIS was selected after evaluating its characteristics of capacity versus price, because the resulting system will be delivered to each of the Centers of the Ministry of Communications and Transports in the states of Mexico. The system is developed by integrating into Arc View a series of data for the state considered, including cartographic representation, classification and naming of roads, traffic volume and composition, and information on accidents. The information referred to in the work corresponds to 1997.

In the past few years, tools have been developed based on different communication means with the purpose of achieving a safer, more efficient, and environment-friendly operation of vehicular flows in the transport systems. Some of the early means generally involved a very strong human participation. In the course of time and with the rapid progress made in electronics, telecommunications, and computer systems, such processes have become automated until generating a series of technologies that currently are incorporated into the single generic term of intelligent transportation systems (ITS). This research has multiple purposes. First, some characteristics of road freight transport in Mexico are presented. Then, with such characteristics under consideration, the ITS technologies with the largest potential for application to that transportation type are described. A vision of future implementation is shown. Finally, some conclusions are presented.

Two years ago, the Mexican Transportation Institute began to develop a computer-based management system of the information collected by various organizations about accidents occurring on the Federal Road Network. This system combines the information gathered by these organizations with the purpose of completing and validating the data so that tools can be developed for processing and analyzing the validated data and the processed data and developed tools can be made available to users. It was decided to support the development of such efforts on computer databases already being generated, on database processing and management software, on geographic information systems, and on remote data-exchange systems (e.g., the Internet). The progress made so far in the development of the computer system is reviewed. The system has been named the “Relational Accident Database Management System for Mexican Federal Roads” (SAIACF, in Spanish). The information sources beneficial to this project are identified and analyzed. The ideal scheme conceived for the integration of the various information sources is presented, and the SAIACF system is outlined. Some of the results obtained after its application to the information corresponding to 1997 are shown. Also, the element that was generated to make the information and the tools available to users is described, and conclusions are drawn.

Truck and rail freight transportation are considered as a first stage in an effort to analyze, by means of network assignment models, freight transportation operations between Mexico and the United States. A set of background information is first presented (i.e., the evolution of trade between Mexico and the United States, participation of rail and truck in this commercial exchange, and modal share between these two modes in such a trade). The assignment model that was developed to predict the freight flows in the truck and rail intermodal network for different product categories (multiproduct) is then described. Finally, values that characterize the operation of the land modes for freight transportation between Mexico and the United States are quantified. Results and analyses that were derived from the model include quantification of ton-kilometers and transportation costs for each product type, as well as assessment of the minimum-cost freight modal share between truck and rail. Some of the analyses presented are by product category (disaggregated), whereas others correspond to the aggregated demand. Most of the analyses reported herein correspond to 1996. The growth trends of the freight volumes between the two countries, together with the optimal share results obtained, are indicative of a conspicuous growth potential for the demand of rail transportation in this type of commercial exchange.

The current modal share between highway and railroad in freight land transportation in Mexico is presented. Based on available origin and destination (O-D) data, the most important origin and destination points of freight transportation by both modes are identified. Information is also provided on the multicommodity flows taking place in Mexico. The O-D information and network assignment analyses are used to establish the major Mexican land transport corridors and their characteristics. The possible extension of these corridors to the U.S. road and railroad corridors that are more important for the binational trade is indicated. Data about the recent evolution of this trade are presented. Only freight transportation is discussed.

Several statistics concerning the occurrence of accidents on the most important fraction of the Mexican highway system (basic network) are given. The involvement of cargo trucks in these accidents is discussed. The factors that contribute most to the occurrence of accidents are identified. Among these factors, those related to the speed of the vehicles that make up the traffic flows stand out. An economic analysis to determine the optimum speed limits and highway design speeds is provided. This analysis is based on depicting, for a given road section, the trend of vehicle operating costs (VOCs), accident costs, and the sum of both with respect to speed. The trend of accident costs is determined from assessment of the average cost per accident in the basic network and prediction of the variation of accident rate with respect to mean flow speed. The VOC trend is obtained by using the World Bank VOC model, calibrated for Mexican conditions. Some recommendations for improving existing speed laws and the enforcement of the regulating system are presented. Other actions for generating a national road safety program are mentioned.

A field study begun in Mexico in 1991 is described. This study has become an annual task without a deadline. The fieldwork seeks knowledge about truck traffic on Mexican roads, type of vehicles used, vehicle size and weight, tonnage transported, routes followed, type of freight moved in each case, origin and destination of movements, the packaging system for the transported freight, and whether the movement is related to domestic or to international trade. From these data, which are the core of the information gathered, other data can be obtained, such as each vehicle’s degree of compliance with current size and weight regulations, the economic value of the freight transported, age of the fleet examined, empty vehicles detected, occupancy rate of each truck (cargo tonnage/maximum payload), and fuel type used. This study is described, and some examples of the information it provides based on the collected data are provided. Also, some of the most important applications for the acquired information are enumerated.

The results of a research project undertaken by the Mexican Transport Institute and the Freight Transportation and Distribution Systems Department of the Autonomous University of Querétaro for generating design recommendations in adding lanes for trucks on Mexican two-lane, two-way roads are presented. Implementation of additional lanes traditionally has been considered among the most efficient low-cost improvements on specific grades (longer than 800 m and steeper than 3 percent). This paper discusses the problem of improving traffic operations on composite grades (a series of consecutive grades with different gradients) that are located in rolling or mountainous terrain by implementing added lanes in both directions. This can be done in a series of appropriate subsegments. Basically, these subsegments are in places that lack the necessary passing sight distance. The longest traffic platoons usually occur in these places.

As in most developing countries, the resources available in Mexico for improving the infrastructure of the transportation system and its services are frequently insufficient. This situation has led the Mexican Transport Institute (MTI) to develop strategies for optimizing the allocation of resources among the various necessities of the system. The use of the economic value of the freight flows for identifying and planning improvement projects to be undertaken for a specified time period on basic surface transportation networks (roads and railways) is proposed. This parameter can also be used for assessing the relative importance of the components of such networks. The methodology suggested for assessing the economic value of the freight flows is presented. The basis of the use of the criterion proposed including its greater convenience than other commonly used criteria (of the benefit/cost type) is described. Based on the suggested criterion, several considerations are raised for the Mexican road and railroad networks. The belief of some policy makers that freight is of paramount importance for planning improvements to the transportation systems is applied and facilitated by the applications described.

A methodology for determining the tariffs that should be charged for different types of vehicles driven on new toll roads in Mexico is presented. The methodology is based on two criteria: maximize the income of the toll collector (whether this collector is a government agency or a private concessionaire) and minimize national transport costs. The first criterion requires the development of binary logit models for predicting the traffic demand fraction choosing the toll alternative. The second criterion requires the minimization of road users' transport cost, which is composed of vehicle operating costs plus the tariff charged. This tariff should include road deterioration costs, construction and financial costs, the administrative costs of operating the toll road, taxes, and other expenditures. Principles for computing reference tariffs are recommended along with ways to use these tariffs to analyze the economic feasibility of toll highways.

Background It is believed to be the standard of care to obtain a blood culture in a child who is hospitalized for pneumonia. In recent years, many studies have questioned the utility of this practice in the presence of age appropriate immunization. We conducted this study to determine the current prevalence of bacteremia in children with uncomplicated pneumonia and the utility of obtaining blood cultures in these children. Objective To evaluate the risk of bacteremia in hospitalized young children with pneumonia. Methods This was a retrospective review from July 2003 until July 2008. The setting was the pediatric emergency department of an urban teaching hospital. The study population included children under 36 months of age who had been fully immunized and who had been hospitalized with radiographic evidence of uncomplicated pneumonia. Excluded were children who were currently using antibiotics or who had used antibiotics within the previous 48 hours, as well as children with immunodeficiency status such as sickle cell anemia, immunoglobulin deficiency, or children on steroid therapy. The radiologist's interpretation of each chest radiograph was reviewed and recorded. The variables studied were age (in months), gender, race, birth history, pneumococcal vaccination status, appearance on arrival, temperature on arrival, respiratory rate, oxygen saturation, white blood cell (WBC) count, neutrophil count, band count, and urine culture. The chi-square test and logistic regression were used to analyze the data. Results A blood culture was obtained in 535 children hospitalized with radiographic pneumonia. Bacteremia was present in 12 children (2.2%). All organisms isolated from the blood cultures were considered contaminants. Conclusion Children hospitalized with uncomplicated pneumonia have a low rate of positive blood cultures. None of the variables studied predicted bacteremia. The absence of true-positive cultures among the organisms isolated suggests little value in obtaining blood cultures in children hospitalized due to uncomplicated pneumonia.