Showing papers by "University of Costa Rica published in 2008"

Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation

Abstract: We present a new map depicting the first global biogeographic regionalization of Earth's freshwater systems. This map of freshwater ecoregions is based on the distributions and compositions of freshwater fish species and incorporates major ecological and evolutionary patterns. Covering virtually all freshwater habitats on Earth, this ecoregion map, together with associated species data, is a useful tool for underpinning global and regional conservation planning efforts (particularly to identify outstanding and imperiled freshwater systems); for serving as a logical framework for large-scale conservation strategies; and for providing a global-scale knowledge base for increasing freshwater biogeographic literacy. Preliminary data for fish species compiled by ecoregion reveal some previously unrecognized areas of high biodiversity, highlighting the benefit of looking at the world's freshwaters through a new framework.

One-third of reef-building corals face elevated extinction risk from climate change and local impacts

Abstract: The conservation status of 845 zooxanthellate reef-building coral species was assessed by using International Union for Conservation of Nature Red List Criteria. Of the 704 species that could be assigned conservation status, 32.8% are in categories with elevated risk of extinction. Declines in abundance are associated with bleaching and diseases driven by elevated sea surface temperatures, with extinction risk further exacerbated by local-scale anthropogenic disturbances. The proportion of corals threatened with extinction has increased dramatically in recent decades and exceeds that of most terrestrial groups. The Caribbean has the largest proportion of corals in high extinction risk categories, whereas the Coral Triangle (western Pacific) has the highest proportion of species in all categories of elevated extinction risk. Our results emphasize the widespread plight of coral reefs and the urgent need to enact conservation measures.

Genetic consequences of habitat fragmentation in plant populations: susceptible signals in plant traits and methodological approaches

Abstract: Conservation of genetic diversity, one of the three main forms of biodiversity, is a fundamental concern in conservation biology as it provides the raw material for evolutionary change and thus the potential to adapt to changing environments. By means of meta-analyses, we tested the generality of the hypotheses that habitat fragmentation affects genetic diversity of plant populations and that certain life history and ecological traits of plants can determine differential susceptibility to genetic erosion in fragmented habitats. Additionally, we assessed whether certain methodological approaches used by authors influence the ability to detect fragmentation effects on plant genetic diversity. We found overall large and negative effects of fragmentation on genetic diversity and outcrossing rates but no effects on inbreeding coefficients. Significant increases in inbreeding coefficient in fragmented habitats were only observed in studies analyzing progenies. The mating system and the rarity status of plants explained the highest proportion of variation in the effect sizes among species. The age of the fragment was also decisive in explaining variability among effect sizes: the larger the number of generations elapsed in fragmentation conditions, the larger the negative magnitude of effect sizes on heterozygosity. Our results also suggest that fragmentation is shifting mating patterns towards increased selfing. We conclude that current conservation efforts in fragmented habitats should be focused on common or recently rare species and mainly outcrossing species and outline important issues that need to be addressed in future research on this area.

Geographic Patterns of Genome Admixture in Latin American Mestizos

Abstract: The large and diverse population of Latin America is potentially a powerful resource for elucidating the genetic basis of complex traits through admixture mapping. However, no genome-wide characterization of admixture across Latin America has yet been attempted. Here, we report an analysis of admixture in thirteen Mestizo populations (i.e. in regions of mainly European and Native settlement) from seven countries in Latin America based on data for 678 autosomal and 29 X-chromosome microsatellites. We found extensive variation in Native American and European ancestry (and generally low levels of African ancestry) among populations and individuals, and evidence that admixture across Latin America has often involved predominantly European men and both Native and African women. An admixture analysis allowing for Native American population subdivision revealed a differentiation of the Native American ancestry amongst Mestizos. This observation is consistent with the genetic structure of pre-Columbian populations and with admixture having involved Natives from the area where the Mestizo examined are located. Our findings agree with available information on the demographic history of Latin America and have a number of implications for the design of association studies in population from the region.

Snake Venomics of the Lancehead Pitviper Bothrops asper: Geographic, Individual, and Ontogenetic Variations

Abstract: We report the comparative proteomic characterization of the venoms of adult and newborn specimens of the lancehead pitviper Bothrops asper from two geographically isolated populations from the Caribbean and the Pacific versants of Costa Rica. The crude venoms were fractionated by reverse-phase HPLC, followed by analysis of each chromatographic fraction by SDS-PAGE, N-terminal sequencing, MALDI-TOF mass fingerprinting, and collision-induced dissociation tandem mass spectrometry of tryptic peptides. The two B. asper populations, separated since the late Miocene or early Pliocene (8−5 mya) by the Guanacaste Mountain Range, Central Mountain Range, and Talamanca Mountain Range, contain both identical and different (iso)enzymes from the PLA2, serine proteinase, and SVMP families. Using a similarity coefficient, we estimate that the similarity of venom proteins between the two B. asper populations may be around 52%. Compositional differences between venoms among different geographic regions may be due to evoluti...

Differential effect of environment enrichment and social isolation on depressive-like behavior, spontaneous activity and serotonin and norepinephrine concentration in prefrontal cortex and ventral striatum

Abstract: In order to determine the effect of postnatal environments on some behavioral and neurochemical depressive-like parameters, male Sprague-Dawley rats were reared from weaning in either social isolation, standard laboratory conditions, or environmental enrichment. Open-field activity was assessed at postnatal days 37, 65, 93 and 107 and 1 h before the last open-field test, a forced-swimming test was carried out. After behavioral tests, the monoamines concentrations were analyzed in prefrontal cortex and ventral striatum. Relative to control and isolation rearing, the environmental enrichment reduced open-field activity, led to antidepressive-like effects and increased serotonin concentrations in the prefrontal cortex. Social isolation, on the other hand, did not affect open-field activity, but increased depressive-like behavior and reduced the amount of norepinephrine in the ventral striatum. Those neurochemical changes induced by rearing conditions correlated with the behavioral performance in the forced-swimming test. Also, immobility behavior could be predicted by locomotor activity even from the first week of housing. Overall, specific variations in physical and social environment during early rearing lead to some behavioral and neurochemical alterations which might be relevant for understanding the role that neurodevelopmental and experiential factors could have in human depression.

Cellular pathology induced by snake venom phospholipase A2 myotoxins and neurotoxins: common aspects of their mechanisms of action

Abstract: A large variety of snake toxins evolved from PLA2 digestive enzymes through a process of ‘accelerated evolution’. These toxins have different tissue targets, membrane receptors and mechanisms of alteration of the cell plasma membrane. Two of the most commonly induced effects by venom PLA2s are neurotoxicity and myotoxicity. Here, we will discuss how these snake toxins achieve a similar cellular lesion, which is evolutionarily highly conserved, despite the differences listed above. They cause an initial plasma membrane perturbation which promotes a large increase of the cytosolic Ca2+ concentration leading to cell degeneration, following modes that we discuss in detail for muscle cells and for the neuromuscular junction. The different systemic pathophysiological consequences caused by these toxins are not due to different mechanisms of cell toxicity, but to the intrinsic anatomical and physiological properties of the targeted tissues and cells.

The Intra-Americas Sea Low-level Jet

Abstract: A relevant climate feature of the Intra-Americas Sea (IAS) is the low-level jet (IALLJ) dominating the IAS circulation, both in summer and winter; and yet it is practically unknown with regard to its nature, structure, interactions with mid-latitude and tropical phenomena, and its role in regional weather and climate. This paper updates IALLJ current knowledge and its contribution to IAS circulation-precipitation patterns and presents recent findings about the IALLJ based on first in situ observations during Phase 3 of the Experimento Climatico en las Albercas de Agua Calida (ECAC), an international field campaign to study IALLJ dynamics during July 2001. Nonhydrostatic fifth-generation Pennsylvania State University National Center for Atmospheric Research Mesoscale Model (MM5) simulations were compared with observations and reanalysis. Large-scale circulation patterns of the IALLJ northern hemisphere summer and winter components suggest that trades, and so the IALLJ, are responding to land-ocean thermal contrasts during the summer season of each continent. The IALLJ is a natural component of the American monsoons as a result of the continent's approximate north-south land distribution. During warm (cold) El Nino-Southern Oscillation phases, winds associated with the IALLJ core (IALLJC) are stronger (weaker) than normal, so precipitation anomalies are positive (negative) in the western Caribbean near Central America and negative (positive) in the central IAS. During the ECAC Phase 3, strong surface winds associated with the IALLJ induced upwelling, cooling down the sea surface temperature by 1-2 degrees C. The atmospheric mixed layer height reached 1 km near the surface wind maximum below the IALLJC. Observations indicate that primary water vapor advection takes place in a shallow layer between the IALLJC and the ocean surface. Latent heat flux peaked below the IALLJC. Neither the reanalysis nor MM5 captured the observed thermodynamic and kinematic IALLJ structure. So far, IALLJ knowledge is based on either dynamically initialized data or simulations of global (regional) models, which implies that a more systematic and scientific approach is needed to improve it. The Intra-Americas Study of Climate Processes is a great regional opportunity to address trough field work, modeling, and process studies, many of the IALLJ unknown features.

Light-Front Dynamics and AdS/QCD Correspondence: Gravitational Form Factors of Composite Hadrons

Abstract: Light-front holography is a remarkable feature of the AdS/CFT correspondence between gravity in AdS space and conformal field theories in physical space-time; it allows string modes $\ensuremath{\Phi}(z)$ in the anti-de Sitter (AdS) fifth dimension to be precisely mapped to the light-front wave functions of hadrons in physical space-time in terms of a specific light-front impact variable $\ensuremath{\zeta}$ which measures the separation of the quark and gluonic constituents within the hadron. This mapping was originally obtained by matching the exact expression for electromagnetic current matrix elements in AdS space with the corresponding exact expression for the current matrix element using light-front theory in physical space-time. In this paper we show that one obtains the identical holographic mapping using matrix elements of the energy-momentum tensor. To prove this, we show that there exists a correspondence between the matrix elements of the energy-momentum tensor of the fundamental hadronic constituents in QCD with the transition amplitudes describing the interaction of string modes in AdS space with an external graviton field which propagates in the AdS interior. The agreement of the results for electromagnetic and gravitational hadronic transition amplitudes provides an important consistency test and verification of holographic mapping from AdS to physical observables defined on the light front.

Snake Venomics and Antivenomics of the Arboreal Neotropical Pitvipers Bothriechis lateralis and Bothriechis schlegelii

Abstract: We report the comparative proteomic characterization of the venoms of two related neotropical arboreal pitvipers from Costa Rica of the genus Bothriechis, B. lateralis (side-striped palm pit viper) and B. schlegelii (eyelash pit viper). The crude venoms were fractionated by reverse-phase HPLC, followed by analysis of each chromatographic fraction by SDS-PAGE, N-terminal sequencing, MALDI-TOF mass fingerprinting, and collision-induced dissociation tandem mass spectrometry of tryptic peptides. The venom proteomes of B. lateralis and B. schlegelii comprise similar number of distinct proteins belonging, respectively, to 8 and 7 protein families. The two Bothriechis venoms contain bradykinin-potentiating peptides (BPPs), and proteins from the phospholipase A 2 (PLA 2), serine proteinase, l-amino acid oxidase (LAO), cysteine-rich secretory protein (CRISP), and Zn (2+)-dependent metalloproteinase (SVMP) families, albeit each species exhibit different relative abundances. Each venom also contains unique components, for example, snake venom vascular endothelial growth factor (svVEGF) and C-type lectin-like molecules in B. lateralis, and Kazal-type serine proteinase inhibitor-like proteins in B. schlegelii. Using a similarity coefficient, we estimate that the similarity of the venom proteins between the two Bothriechis taxa may be <10%, indicating a high divergence in their venom compositions, in spite of the fact that both species have evolved to adapt to arboreal habits. The major toxin families of B. lateralis and B. schlegelii are SVMP (55% of the total venom proteins) and PLA 2 (44%), respectively. Their different venom toxin compositions provide clues for rationalizing the distinct signs of envenomation caused by B. schlegelii and B. lateralis. An antivenomic study of the immunoreactivity of the Instituto Clodomiro Picado (ICP) polyvalent antivenom toward Bothriechis venoms revealed that l-amino acid oxidase and SVMPs represent the major antigenic protein species in both venoms. Our results provide a ground for rationalizing the reported protection of the ICP polyvalent antivenom against the hemorrhagic, coagulant, defibrinating, caseinolytic and fibrin(ogen)olytic activities of Bothriechis ( schlegelii, lateralis) venoms. However, these analyses also evidenced the limited recognition capability of the polyvalent antivenom toward a number of Bothriechis venom components, predominantly BPPs, svVEGF, Kazal-type inhibitors, some PLA 2 proteins, some serine proteinases, and CRISP molecules.

The annual cycle in a tropical wet forest hummingbird community

Abstract: Summary In the Caribbean lowlands of Costa Rica, rainfall is moderately seasonal, although even in the driest month over 100 mm of rain usually fall. Flowering of hummingbird food plants shows a peak in the dry season (February-April) and another in the early wet season (July-September), with a severe flower shortage at the end of the rains (November-December). The dry season peak involves largely canopy epiphytes, the wet season peak large herbs of light gaps and edges and forest understory plants. This study examines the responses of the associated community of 22 species of hummingbirds (of which 13 breed, and 12 are common for at least parts of most years) to these spatial and temporal patterns of resource availability. Nearly all common breeding species show a peak of reproductive activity in the dry season, coinciding with the first flowering peak, followed by a discrete moulting season that coincides with the wet season peak of flowering. Of the three species with extended breeding seasons, the two species of hermit, Phaethornis, show moult-breeding overlap to varying degrees on an individual basis. In a number of species moult and breeding appear antagonistic. The annual peak of body weight and fat deposits in all species occur during the second flowering peak, approximately corresponding to the moult. The annual minima of body weight and fat occur in the lean season and the breeding season respectively. The lack of concordance of these two possibly reflects the use of muscle protein as a nutrient source during the lean season. Several species show pronounced habitat shifts through the year, with the sexes sometimes occupying different microhabitats, especially during the dry season. At least five species show pronounced seasonal migrations, largely or entirely leaving La Selva for part of the year. Overall hummingbird numbers are greatest early in the rainy season, lowest in the lean season, with the non-hermits (Trochilinae) showing a more pronounced annual cycle of numbers than the hermits (Phaethorninae). Comparisons with other tropical lowland hummingbird-flower communities are made with respect to the roles of flowers as proximate and ultimate factors regulating the annual cycles and affecting the population biology of the birds.

Cannabinoid receptor 1 gene (CNR1) and susceptibility to a quantitative phenotype for hebephrenic schizophrenia

Abstract: Functional alterations of components of the endogenous cannabinoid system, in particular of the cannabinoid receptor 1 protein (CB1), are hypothetical contributors to many of the symptoms seen in schizophrenia. Variants within the cannabinoid receptor 1 gene (CNR1) have been shown to be directly associated with the hebephrenic form of schizophrenia in a Japanese population. This finding, however, has yet to be replicated. In the present study we sought to study the same (AAT)n-repeat microsatellite of the CNR1 gene which showed association to hebephrenic schizophrenia in Japan, and to investigate whether this microsatellite showed association to a hebephrenic type of schizophrenia in a family-based association study in a population of the Central Valley of Costa Rica. The Lifetime Dimensions of Psychosis Scale and a best estimate consensus process were utilized to identify subjects with schizophrenia who had an elevated lifetime dimensional score for negative and disorganized symptoms, which we used as a proxy for “hebephrenia.” Using the Family Based Association Test we found association of these hebephrenic subjects and the (AAT)n-repeat marker of the CNR1 (multi-allelic P = 0.0368). Our hypothesis that an association with the (AAT)n-repeat marker of CNR1 would not be found with the more general type of schizophrenia was also confirmed. Schizophrenic subjects with prominent lifetime scores for disorganization and negative symptoms (dimension for hebephrenia) are associated with the CNR1 gene and present a type of symptomatology that resembles chronic cannabinoid-induced psychosis. The current finding points to the possibility of different genetic and pathophysiologic mechanisms underlying different types of schizophrenia. © 2008 Wiley-Liss, Inc.

Comparison of Two PCR-Based Human Papillomavirus Genotyping Methods

Abstract: We compared two consensus primer PCR human papillomavirus (HPV) genotyping methods for the detection of individual HPV genotypes and carcinogenic HPV genotypes as a group, using a stratified sample of enrollment cervical specimens from sexually active women participating in the NCI/Costa Rica HPV16/18 Vaccine Efficacy Trial. For the SPF10 method, DNA was extracted from 0.1% of the cervical specimen by using a MagNA Pure LC instrument, a 65-bp region of the HPV L1 gene was targeted for PCR amplification by using SPF10 primers, and 25 genotypes were detected by reverse-line blot hybridization of the amplicons. For the Linear Array (LA) method, DNA was extracted from 0.5% of the cervical specimen by using an MDx robot, a 450-bp region of the HPV L1 gene was targeted for PCR amplification by using PGMY09/11 L1 primers, and 37 genotypes were detected by reverse-line blot hybridization of the amplicons. Specimens (n = 1,427) for testing by the LA method were randomly selected from strata defined on the basis of enrollment test results from the SPF10 method, cytology, and Hybrid Capture 2. LA results were extrapolated to the trial cohort (n = 5,659). The LA and SPF10 methods detected 21 genotypes in common; HPV16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, -68, and -73 were considered the carcinogenic HPV genotypes. There was no difference in the overall results for grouped detection of carcinogenic HPV by the SPF10 and LA methods (35.3% versus 35.9%, respectively; P = 0.5), with a 91.8% overall agreement and a kappa value of 0.82. In comparisons of individual HPV genotypes, the LA method detected significantly more HPV16, HPV18, HPV39, HPV58, HPV59, HPV66, and HPV68/73 and less HPV31 and HPV52 than the SPF10 method; inclusion of genotype-specific testing for HPV16 and HPV18 for those specimens testing positive for HPV by the SPF10 method but for which no individual HPV genotype was detected abrogated any differences between the LA and SPF10 methods. The LA method detected more carcinogenic-HPV-genotype infections per specimen than the SPF10 method (P

Snake Venomics of Central American Pitvipers: Clues for Rationalizing the Distinct Envenomation Profiles of Atropoides nummifer and Atropoides picadoi

Abstract: We report the proteomic characterization of the Central American pitvipers Atropoides nummifer and Atropoides picadoi The crude venoms were fractionated by reverse-phase high-performance liquid chromatography (HPLC), followed by analysis of each chromatographic fraction by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), N-terminal sequencing, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass fingerprinting, and collision-induced dissociation-tandem mass spectrometry (CID-MS/MS) of tryptic peptides Each venom contained a number of bradykinin-potentiating peptides and around 25-27 proteins of molecular masses in the range of 7-112 kDa, belonging to only nine different toxin families (disintegrin, DC fragment, snake venom vascular endothelial growth factor, phospholipases A2, serine protease, cysteine-rich secretory proteins, C-type lectins, L-amino acid oxidase, and Zn2+-dependent metalloproteases), albeit distinctly distributed among the two Atropoides species In addition, A nummifer expresses low amounts of a three-finger toxin not detected in the venom of A picadoi The major toxins of A nummifer belong to the PLA2 (relative abundance, 365%) and the serine proteinase (22%) families, whereas the most abundant A picadoi toxins are Zn2+-dependent metalloproteinases (664%) We estimate that the similarity of venom proteins between the two Atropoides taxa may be around 14-16% The high degree of differentiation in the venom proteome among congeneric taxa emphasizes unique aspects of venom composition of related species of Atropoides snakes and points to a strong role for adaptive diversification via natural selection as a cause of this distinctiveness On the other hand, their distinct venom toxin compositions provide clues for rationalizing the low hemorrhagic, coagulant, and defibrinating activities and the high myotoxic and proteolytic effects evoked by A nummifer snakebite in comparison to other crotaline snake venoms and the high hemorrhagic activity of A picadoi

Growth hormone deficiency in children.

Abstract: The foundation for the diagnosis of growth hormone (GH) deficiency in childhood must be auxology, that is, the comparison of the child's growth pattern to that of established norms for gender and ethnicity. It is only in those growing considerably more slowly than average that testing for GHD makes sense. Assessment of laboratory tests, whether static, for example, the measurement of growth factors or their binding proteins, or dynamic, for example, secretagogue-stimulated GH secretion is confirmatory. One must be cognizant of the assay used to determine GH, for there may be a 3-fold difference in the concentration of GH among commercially-available assays. Controversy still exists concerning the measurement of spontaneous GH release and whether sex-steroid priming is appropriate in prepubertal children. Imaging analysis may prove helpful in some children with congenital GHD or to detect a space-occupying lesion in the area of the hypothalamus and pituitary. The final diagnosis is based on multiple parameters and occasionally on a therapeutic trial of GH therapy to determine if there is a significant acceleration of growth velocity.

Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes.

Abstract: Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

Seasonal profiles of Aedes aegypti (Diptera: Culicidae) larval habitats in an urban area of Costa Rica with a history of mosquito control

Abstract: Dengue is the most important arboviral disease worldwide and the principal vector-borne disease in Costa Rica. Control of Aedes aegypti populations through source reduction is still considered the most effective way of prevention and control, although it has proven ineffective or unsustainable in many areas with a history of mosquito control. In this study, seasonal profiles and productivity of Aedes aegypti were analyzed in the city of Puntarenas, Costa Rica, where vector control has been practiced for more than ten years. Households contained more than 80% of larval habitats identified, although presence of habitats was more likely in other locations like lots and streets. In the wet season, habitats in the “other” category, like appliances, small manholes, and miscellaneous containers, were the most frequent habitats observed as well as the most common and productive habitats for Ae. aegypti. In the dry season, domestic animal drinking containers were very common, although concrete washtubs contained 79% of Ae. aegypti pupae collected. Individually, non-disposable habitats were as likely or more likely to contain mosquito larvae, and large containers were more likely to harbor mosquito larvae than the small ones only in the dry season. Considering various variables in the logistic regressions, predictors for Ae. aegypti in a habitat were habitat type (p<0.001), setting (p=0.043), and disposability (p=0.022) in the wet season and habitat capacity in the dry season (p=0.025). Overall, traditional Ae. aegypti larval indices and pupal indices in Puntarenas were high enough to allow viral transmission during the wet season. In spite of continued vector control, it has not been possible to reduce vector densities below threshold levels in Puntarenas, and the habitat profiles show that non-household locations, as well as non-disposable containers, should be targeted in addition to the standard control activities.

A conceptual model for temporal data warehouses and its transformation to the ER and the object-relational models

Abstract: The MultiDim model is a conceptual multidimensional model for data warehouse and OLAP applications. These applications require the presence of a time dimension to track changes in measure values. However, the time dimension cannot be used to represent changes in other dimensions. In this paper we introduce a temporal extension of the MultiDim model. This extension is based on research realized in temporal databases. We allow different temporality types: valid time, transaction time, and lifespan, which are obtained from source systems, and loading time, which is generated in the data warehouse. Our model provides temporal support for levels, attributes, hierarchies, and measures. For hierarchies we discuss different cases depending on whether the changes in levels or in the relationships between them must be kept. For measures, we give different scenarios that show the usefulness of the different temporality types. Further, since measures can be aggregated before being inserted into data warehouses, we discuss the issues related to different time granularities between source systems and data warehouses. We finish the paper presenting a transformation of the MultiDim model into the entity-relationship and the object-relational models.

Factors associated with hypertension prevalence, unawareness and treatment among Costa Rican elderly.

Abstract: Reliable information on the prevalence of hypertension is crucial in the development of health policies for prevention, control, and early diagnosis of this condition. This study describes the prevalence of hypertension among Costa Rican elderly, and identifies co-factors associated with its prevalence, unawareness and treatment. The prevalence of hypertension is estimated for the Costa Rican elderly. Measurement error is assessed, and factors associated with high blood pressure are explored. Data for this study came from a nationally representative sample of about 2,800 individuals from CRELES (Costa Rica: Longevity and Healthy Aging Study). Two blood pressure measures were collected using digital monitors. Self reports of previous diagnosis, and medications taken were also recorded as part of the study. No evidence of information bias was found among interviewers, or over time. Hypertension prevalence in elderly Costa Ricans was found to be 65% (Males = 60%, Females = 69%). Twenty-five percent of the studied population did not report previous diagnoses of hypertension, but according to our measurement they had high blood pressure. The proportion of unaware men is higher than the proportion of unaware women (32% vs. 20%). The main factors associated with hypertension are: age, being overweight or obese, and family history of hypertension. For men, current smokers are 3 times more likely to be unaware of their condition than non smokers. Both men and women are less likely to be unaware of their condition if they have a family history of hypertension. Those women who are obese, diabetic, have suffered heart disease or stroke, or have been home visited by community health workers are less likely to be unaware of their hypertension. The odds of being treated are higher in educated individuals, those with a family history of hypertension, elderly with diabetes or those who have had heart disease. Sex differences in terms of hypertension prevalence, unawareness, and treatment in elderly people have been found. Despite national programs for hypertension detection and education, unawareness of hypertension remains high, particularly among elderly men. Modifiable factors identified to be associated with prevalence such as obesity and alcohol intake could be used in educational programs aimed at the detection and treatment of those individuals who have the condition.

Characterization of true-branching cyanobacteria from geothermal sites and hot springs of Costa Rica.

Abstract: Costa Rica is at the centre of the Mesoamerican biodiversity hotspot. Little is known about cyanobacteria from this region so far. Here, four isolates of the order Stigonematales (section V) were characterized in a polyphasic approach. All strains were isolated from geothermal sites and hot springs of Costa Rica. However, one of them, identified as Westiellopsis sp. Ar73, did not grow at more than 40 degrees C. Based on its identical 16S rRNA to several previously isolated Westiellopsis sp. and Fischerella muscicola strains, a ubiquitous distribution throughout tropical and subtropical regions can be implied. In contrast, the isolates MV9, MV11 and RV14 grew well up to 50-55 degrees C. Based on morphologic, ultrastructural, molecular and physiologic data, MV9, MV11 and RV14 were identified to belong to the genus Fischerella. Two distinct intergenic transcribed spacer (ITS) types, with or without tRNA genes, were detected for all Stigonematales analysed here, indicating ITS polymorphism as a characteristic feature of heterocystous cyanobacteria. In phylogenetic trees, these Fischerella spp. formed a new and distinct clade within the wider lineage of thermophilic Fischerella (Mastigocladus cf. laminosus), which might represent a geographic lineage. Thus, geographic isolation may be an underestimated aspect of microbial evolution. The strains presented here are suitable as new models to study this group of cyanobacteria.

Historia de la investigación marina de la Isla del Coco, Costa Rica

Abstract: History of marine research at Cocos Island, Costa Rica. The marine organisms and environments of Isla del Coco (Cocos Island), Pacific Costa Rica, were described by explorers in the late 17th to 19th centuries. Scientific studies of the island initiated in late 19th century, during the Albatross Expeditions. The first expedition by Costa Rican scientists was in 1898. Between the 1920’s and 1940’s, many expeditions visited the island and many papers were published, including descriptions of new species and reports on species ocurrence. There were other minor expeditions until the 1970’s when there was a renewed interest on the island. Since then many scientists have collected in the island, and papers are still being published. Starting in the late 1980´s and especially in the last several years, scientists from the Centro de Investigacion en Ciencias del Mar y Limnologia (CIMAR; Marine Sciences and Limnology Research Center) of the Universidad de Costa Rica started visiting the island. Around 1100 species of marine organisms have been reported from Isla del Coco. Of a bibliographic database of 300 scientific publications on marine organisms, ecosystems, behavior and processes, around 70% of the papers are on taxonomy, mainly on mollusks, crustaceans and fishes. New collections are being done, and new groups of organisms, ecosystems and events not studied before are being investigated. This synopsis on the history of marine research points to gaps in our knowledge of the marine organisms, environments and processes at Isla del Coco. Rev. Biol. Trop. 56 (Suppl. 2): 1-18. Epub 2008 August 29.