Previous studies have found that a tightening of the balance of payments (BP) constraint can explain the slowdown in Mexico's growth after its trade liberalization in the late 1980s. This paper develops a disaggregated model of the BP constraint with two types of exports (manufactured and primary commodities) and two types of imports (intermediate and final goods). Econometric estimates (including tests for structural breaks) show that the BPequilibrium growth rate did not fall, but instead rose in the post-liberalization period, so this model cannot account for the country's growth slowdown. Instead, the analysis points to the need to consider the real exchange rate as well as internal obstacles and policies.

This paper estimates a structural model of the balance of payments, with disaggregated exports (manufactures and other) and imports (final and intermediate), and a reduced form model of the trade balance for the Mexican economy. The analysis identifies structural changes in the composition of Mexico's trade and the parameters that affect it across five subperiods marked by statistical breakpoints. The results indicate that a tightening of the balance-of-payments constraint may account for the post-liberalization slowdown in Mexico's growth only during certain subperiods, and that the impact of real exchange rate changes on the trade balance has diminished, most likely as a result of the increasing integration of export industries into global supply chains. The results also suggest an asymmetry, whereby a country cannot sustain growth above the rate consistent with balance-of-payments equilibrium, as expected, but it can grow persistently below that rate when other constraints are more binding.

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The coral snake Micrurus tener tener (Mtt) from the Elapidae family inhabits the southwestern United States and produces severe cases of envenomations. Although the majority of Mtt venom components are neurotoxins and phospholipase A2s, this study demonstrated, by SDS-PAGE and molecular exclusion chromatography (MEC), that these venoms also contain high-molecular-weight proteins between 50 and 150 kDa that target the hemostatic system. The biological aspects of other Micrurus venoms were also studied, such as the LD50s of Micrurus isozonus (from 0.52 to 0.61 mg/kg). A pool from these venoms presented a LD50 of 0.57 mg/kg, Micrurus f. fulvius (Mff) and Mtt had LD50s of 0.32 and 0.78 mg/kg, respectively. These venoms contained fibrino(geno)lytic activity, they inhibited platelet aggregation, as well as factor Xa and/or plasmin-like activities. M. isozonus venoms from different Venezuelan geographical regions inhibited ADP-induced platelet aggregation (from 50 to 68%). Micrurus tener tener venom from the United States was the most active with a 95.2% inhibitory effect. This venom showed thrombin-like activity on fibrinogen and human plasma. Fractions of Mtt showed fibrino(geno)lytic activity and inhibition on plasmin amidolytic activity. Several fractions degraded the fibrinogen Aα chains, and fractions F2 and F7 completely degraded both fibrinogen Aα and Bβ chains. To our knowledge, this is the first report on thrombin-like and fibrino(geno)lytic activity and plasmin or factor Xa inhibitors described in Micrurus venoms. Further purification and characterization of these Micrurus venom components could be of therapeutic use in the treatment of hemostatic disorders.

The objective was to determine the prevalence of iron, folates and retinol deficiencies in school children and to evaluate the changes after an intervention of nutritional education. The project was developed in 17 schools. The sample included 1,301 children (678 males and 623 females). A subsample of 480 individuals, was randomly selected for drawing blood for biochemical determinations before and after the intervention of nutritional education, which included in each school: written pre and post-intervention tests, 6 workshops, 2 participative talks, 5 game activities, 1 cooking course and 1 recipe contest. Anthropometrical and biochemical determinations included weight, height, body-mass index, nutritional status, hematocrit, serum ferritin, retinol and folate concentrations. There was high prevalence of iron (25%), folates (75%) and vitamin A (43%) deficiencies in school children, with a low consumption of fruit and vegetables, high consumption of soft drinks and snacks and almost no physical activity. The nutritional education intervention produced a significant reduction in iron deficiency prevalence (25 to 14%), and showed no effect on vitamin A and folates deficiencies. There was a slight improvement in nutritional status. This study shows, through biochemical determinations, that nutritional education initiatives and programs have an impact improving nutritional health in school children.