University of Costa Rica

About: University of Costa Rica is a education organization based out in San José, Costa Rica. It is known for research contribution in the topics: Population & Venom. The organization has 9817 authors who have published 16781 publications receiving 238208 citations. The organization is also known as: UCR & Universidad de Costa Rica.

Decreased Consumption of Dried Mature Beans Is Positively Associated with Urbanization and Nonfatal Acute Myocardial Infarction

Abstract: Legumes may protect against myocardial infarction (MI). The objective of this study was to determine whether consumption of dried mature beans (referred to as beans), the main legume in Latin America, is associated with MI. The cases (n = 2119) were survivors of a first acute MI and were matched by age, sex, and area of residence to randomly selected population controls (n = 2119) in Costa Rica. Dietary intake was assessed with a validated FFQ. Of the population, 69% consumed > or = 1 serving of beans/d (1 serving = one-third cup of cooked beans, approximately 86 g). Consumption of > or = 1 serving/d was significantly higher (P 1 serving/d). In summary, we found that consumption of 1 serving of beans/d is associated with a 38% lower risk of MI. No additional protection was observed at intakes > 1 serving/d. These findings are timely given the trend toward increased obesity, cardiovascular disease, and a reduction in the intake of beans in Latin American countries.

Spatial Correlation in Multilevel Crash Frequency Models: Effects of Different Neighboring Structures

Abstract: Recent research has shown the importance of spatial correlation in road crash models. Because many different spatial correlation structures are possible, however, this study tested several segment neighboring structures to establish the most promising one to model crash frequency in road networks. A multilevel approach was also used to account for the spatial correlation between road segments of different functional types, which are usually analyzed separately. The study employed a full Bayes hierarchical approach with conditional autoregressive effects for the spatial correlation terms. Analyses of crash, traffic, and roadway inventory data from rural engineering districts in Pennsylvania and Washington affirmed the importance of spatial correlation in road crash models. Pure distance-based neighboring models (i.e., exponential decay) performed poorly compared with adjacency-based or distance order models. The results also suggest that spatial correlation is more important in distances of 1 mi or less. T...

The Extraordinary Ability of Guanidinate Derivatives to Stabilize Higher Oxidation Numbers in Dimetal Units by Modification of Redox Potentials: Structures of Mo25+ and Mo26+ Compounds

Abstract: Full characterization of the first homologous series of dimolybdenum paddlewheel compounds having electronic configurations of the types σ2π4δx, x = 2, 1, 0, and Mo−Mo bond orders of 4, 3.5, and 3, respectively, has been accomplished with the guanidinate-type ligand hpp (hpp = the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine). Essentially quantitative oxidation of Mo2(hpp)4, 1, by CH2Cl2 gives Mo2(hpp)4Cl, 2. The halide in 2 can be replaced by reaction with TlBF4 to produce Mo2(hpp)4(BF4), 3. Further oxidation of 2 by AgBF4 produces Mo2(hpp)4ClBF4, 4. The change from bond order 4 (in 1) to 3.5 in Mo2(hpp)4Cl is accompanied by an increase in the Mo−Mo bond length of 0.061 to 2.1280(4) A. A further increase of 0.044 A in the Mo−Mo distance to 2.172(1) A is observed as the bond order decreases to 3 in 4. At the same time, the Mo−N distances decrease smoothly as the oxidation state of the Mo atoms increases. Electrochemical studies have shown two chemically reversible processes at very negative...