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La Jolla, Costa Rica

The National University of Costa Rica is a public university in the Republic of Costa Rica, in Central America. The main campus is located in the city of Heredia. It is one of five public universities in the country and the second most prestigious. According to the most recent studies based on the international standards used to evaluate universities, The National University of Costa Rica ranks 85th in Latin America and 1576th in the world. Over 12,000 students study at its main campus. In addition to undergraduate programs, it offers 16 Masters of Art degrees and is strong in ecology, sociology and education related coursework. Wikipedia.

Fernandez-Gaxiola A.C.,National University of Costa Rica
Cochrane database of systematic reviews (Online)

Daily iron supplementation has been traditionally a standard practice for preventing and treating anaemia but its long term use has been limited as it has been associated with adverse side effects such as nausea, constipation and teeth staining. Intermittent iron supplementation has been suggested as an effective and safer alternative to daily iron supplementation for preventing and reducing anaemia at population level, especially in areas where this condition is highly prevalent. To assess the effects of intermittent oral iron supplementation, alone or in combination with other nutrients, on anaemia and its associated impairments in menstruating women, compared with no intervention, a placebo or daily supplementation. We searched the following databases in May 2011: CENTRAL (The Cochrane Library 2011, Issue 2), MEDLINE (1948 to May Week 3, 2011), EMBASE (1980 to 2011 Week 20), CINAHL (1937 to current), POPLINE (all available years), Science Citation Index (1970 to 27 May 2011), BIOSIS Previews (1969 to current), and CPCI-S (1990 to 27 May 2011). On 7 July 2011 we searched all available years in the following databases: SCIELO, LILACS, IBECS and IMBIOMED, the Networked Digital Library of Theses and Dissertations, metaRegister and the WHO International Clinical Trials Registry Platform (ICTRP). We also contacted relevant organisations (on 11 October 2011) to identify ongoing and unpublished studies. Randomised and quasi-randomised trials with either individual or cluster randomisation. Participants were menstruating women, that is women beyond menarche and prior to menopause who were not pregnant or lactating and did not have a known condition that impeded the presence of menstrual periods. The intervention was the use of iron supplements intermittently (one, two or three times a week on non-consecutive days) compared with no intervention, a placebo, or the use of same supplements on a daily basis. Two review authors independently assessed the eligibility of studies against the inclusion criteria, extracted data from included studies, checked data entry for accuracy and assessed the risk of bias of the included studies. We included 21 trials involving 10,258 women. Although the quality across trials was variable, the results consistently show that in comparison with no intervention or a placebo, intermittent iron supplementation (alone or with any other vitamins and minerals) reduces the risk of having anaemia (RR 0.73; 95% CI 0.56 to 0.95, 10 trials) and improves the concentration of haemoglobin (MD 4.58 g/L; 95% CI 2.56 to 6.59, 13 trials) and ferritin (MD 8.32 μg/L; 95% CI 4.97 to 11.66, six trials). However, in comparison with daily supplementation, women receiving supplements intermittently presented anaemia more frequently (RR 1.26; 95% CI 1.04 to 1.51, six trials), despite achieving similar haemoglobin concentrations on average (MD -0.15 g/L; 95% CI -2.20 to 1.91, eight trials).Information on disease outcomes, adherence, side effects, economic productivity and work performance is scarce and the evidence about the effects of intermittent supplementation on them is unclear.Overall, whether the supplements were given once or twice weekly, for less or more than three months, contained less or more than 60 mg of elemental iron per week, or to populations with different degrees of anaemia at baseline did not seem to affect the findings. Furthermore, the response did not differ in areas where malaria is frequent, although very few trials were conducted in these settings. Intermittent iron supplementation in menstruating women is a feasible intervention in settings where daily supplementation is likely to be unsuccessful or not possible. In comparison with daily supplementation, the provision of iron supplements intermittently is less effective in preventing or controlling anaemia. More information is needed on morbidity (including malaria outcomes), side effects, work performance, economic productivity, depression and adherence to the intervention. Source

A characteristic mechanism of gene expression regulation during seed germination is the selective translation of mRNAs. Previous findings indicate that the two cap-binding complexes eIF4F (with eIF4E and eIF4G subunits) and eIF(iso)4F [with eIF(iso)4E and eIF(iso)4G subunits] are differentially expressed during maize seed germination. In addition, several studies in vitro have suggested that these factors may participate in selective mRNA translation. The translational activities of eIF4E and eIF(iso)4E were tested in vitro using transcripts from two different sets: dry (0h) and 24-h-imbibed maize embryonic axes. In vitro translation of these mRNA pools in the presence of the recombinant eIF4E or eIF(iso)4E, and the native cap-binding complexes from dry- or 24-h-imbibed axes, produced different profiles of proteins which were visualized by two-dimensional protein gels and autoradiography. The data indicated that eIF(iso)4E was particularly required for translation of the stored mRNAs from dry seeds, and that eIF4E was unable to fully replace the eIF(iso)4E activity. In addition, the dry seed mRNA pool was translated by the cap-binding complex isolated from dry seeds better than by the complex isolated from 24-h-imbibed seeds, whereas the translational efficiency of the mRNA pool from 24-h-imbibed seeds was similar between the cap-binding complexes from these two stages. Interestingly, eIF(iso)4E was more abundant than eIF4E in dry seeds, while both cap-binding proteins were present at similar levels in 24-h-imbibed seeds. These results suggest that the ratio of eIF(iso)4E to eIF4E in the corresponding eIF4F complex is critical for the mechanisms of translational control during maize germination. © 2011 Cambridge University Press. Source

Male reproductive performance in penaeoid aquaculture is a major issue. This review evaluates the current knowledge on male reproduction of open thelyca penaeoid shrimps. This group of shrimp belongs to the genus Penaeus, sub-genus Litopenaeus, and presents a unique reproductive model, characterized by complex spermatophores and thelyca without seminal receptacles; however, sperm seem to reach maturation and capacitation on the open thelyca. Males of this group adapt differently to captivity, being P. (Litopenaeus) vannamei the best adapted species. Nevertheless, three problematic conditions develop in confined environments in one or more species: male reproductive tract degenerative syndrome (MRTDS), male reproductive system melanization (MRSM), and spermatophore deterioration (SD). © 2009 Elsevier B.V. All rights reserved. Source

Basualdo M.,National University of Costa Rica
Computers and Chemical Engineering

In this work, an ontology-based framework for process supervision in chemical plants is presented. A conceptualization of equipment, control systems and hazards has been developed. This conceptual model includes the semantic of each modeled term in order to obtain a heavyweight ontology. The ontology has been formalized using Description Logic (DL) (Krötzsch et al., 2012). A knowledge-driven approach has been adopted in order to demonstrate how DL reasoning could be used to support process supervision, detecting and diagnosing faults, without the help of external agents. In the proposed approach, a DL reasoner adds implicit facts to the ontology through forward chaining reasoning, from the current measurements to the characterization of hazards. Additionally, the system is able to check knowledge consistency and formally explain the obtained results. The system functionality has been illustrated in the Tennessee Eastman process.benchmark. © 2013 Elsevier Ltd. Source

Correa-Rotter R.,Instituto Nacional Of Ciencias Medicas Y Nutricion Salvador Zubiran | Wesseling C.,National University of Costa Rica | Johnson R.J.,University of Colorado at Denver
American Journal of Kidney Diseases

An epidemic of chronic kidney disease of unknown origin has emerged in the last decade in Central America and has been named Mesoamerican nephropathy. This form of chronic kidney disease is present primarily in young male agricultural workers from communities along the Pacific coast, especially workers in the sugarcane fields. In general, these men have a history of manual labor under very hot conditions in agricultural fields. Clinically, they usually present with normal or mildly elevated systemic blood pressure, asymptomatic yet progressive reduction in estimated glomerular filtration rate, low-grade non-nephrotic proteinuria, and often hyperuricemia and or hypokalemia. Diabetes is absent in this population. Kidney biopsies that have been performed show a chronic tubulointerstitial disease with associated secondary glomerulosclerosis and some signs of glomerular ischemia. The cause of the disease is unknown; this article discusses and analyzes some of the etiologic possibilities currently under consideration. It is relevant to highlight that recurrent dehydration is suggested in multiple studies, a condition that possibly could be exacerbated in some cases by other conditions, including the use of nonsteroidal anti-inflammatory agents. At present, Mesoamerican nephropathy is a medical enigma yet to be solved. © 2014 by the National Kidney Foundation, Inc. Source

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