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.

Supersymmetry across the light and heavy-light hadronic spectrum

Abstract: Relativistic light-front bound-state equations for mesons and baryons can be constructed in the chiral limit from the supercharges of a superconformal algebra which connect baryon and meson spectra. Quark masses break the conformal invariance, but the basic underlying supersymmetric mechanism, which transforms meson and baryon wave functions into each other, still holds and gives remarkable connections across the entire spectrum of light and heavy-light hadrons. We also briefly examine the consequences of extending the supersymmetric relations to double-heavy mesons and baryons.

Barriers and facilitating factors for disease self-management: a qualitative analysis of perceptions of patients receiving care for type 2 diabetes and/or hypertension in San José, Costa Rica and Tuxtla Gutiérrez, Mexico

Abstract: The burden of cardiovascular disease is growing in the Mesoamerican region. Patients’ disease self-management is an important contributor to control of cardiovascular disease. Few studies have explored factors that facilitate and inhibit disease self-management in patients with type 2 diabetes and hypertension in urban settings in the region. This article presents patients’ perceptions of barriers and facilitating factors to disease self-management, and offers considerations for health care professionals in how to support them. In 2011, 12 focus groups were conducted with a total of 70 adults with type 2 diabetes and/or hypertension who attended urban public health centers in San Jose, Costa Rica and Tuxtla Gutierrez, Chiapas, Mexico. Focus group discussions were transcribed and coded using a content analysis approach to identify themes. Themes were organized using the trans-theoretical model, and other themes that transcend the individual level were also considered. Patients were at different stages in their readiness-to-change, and barriers and facilitating factors are presented for each stage. Barriers to disease self-management included: not accepting the disease, lack of information about symptoms, vertical communication between providers and patients, difficulty negotiating work and health care commitments, perception of healthy food as expensive or not filling, difficulty adhering to treatment and weight loss plans, additional health complications, and health care becoming monotonous. Factors facilitating disease self-management included: a family member’s positive experience, sense of urgency, accessible health care services and guidance from providers, inclusive communication, and family and community support. Financial difficulty, gender roles, differences by disease type, faith, and implications for families and their support were identified as cross-cutting themes that may add an additional layer of complexity to disease management at any stage. These factors also relate to the broader family and societal context in which patients live. People living with type 2 diabetes and hypertension present different barriers and facilitating factors for disease self-management, in part based on their readiness-to-change and also due to the broader context in which they live. Primary care providers can work with individuals to support self-management taking into consideration these different factors and the unique situation of each patient.

Water relations of tropical dry forest flowers: pathways for water entry and the role of extracellular polysaccharides

Abstract: Many trees in tropical dry forests flower during the dry season when evaporative demand is high and soil water levels are low. In this study the factors influencing the water balance of flowers from three species of dry forest trees were examined. Flowers had greater mucilage contents than leaves, high intrinsic and absolute capacitances, long time constants for water exchange and high transfer resistances. Flower water potentials were higher than in leaves and did not fluctuate over the lifespan of the flower. Flower water content also remained constant even though evaporation rates were high, suggesting that water was being supplied from the stem. In two of the species, the water potential gradient between flowers and leaves was opposite to that necessary for water transport from stem to flowers through the xylem, and it was therefore hypothesized that water may enter the flower through the phloem. Calculations showed that nectar production in these flowers could drive a sink of sufficient magnitude to allow water input via the phloem equal to water lost from the flower to the atmosphere.

Reef coral reproduction in the eastern Pacific: Costa Rica, Panamá, and Galápagos Islands (Ecuador). III. Agariciidae ( Pavona gigantea and Gardineroseris planulata )

Abstract: The reproductive ecology of Pavona gigantea Verrill and Gardineroseris planulata (Dana) was investigated in the equatorial eastern Pacific region from 1985 to 1994. These zooxanthellate scleractinian corals were adversely affected in this region during the 1982–1983 El Nino warming event. Both species were hermaphroditic, with individual colonies showing sequential cosexual development, thus resulting in dominantly outbreeding reproduction. Sexuality was mixed, with high percentages of gonochoric and hermaphroditic colonies in both species. Approximately 1:1 male-to-female gonad ratios were found in gonochoric and hermaphroditic colonies combined. Broadcast spawning was observed in P. gigantea in the Galapagos Islands, and the sudden disappearance of mature gametes and the presence of spent gonads suggest that G. planulata is also a broadcast spawner. Colonies of both species with ≲200 cm2 (10 cm diam) live tissue were nonreproductive. Estimated ages of the youngest reproductive colonies were 11 yr for P. gigantea and 20 yr for G. planulata. The percentage of all colonies of P. gigantea with gonads at nonupwelling sites (Cano Istand, Costa Rica and Uva Island, Panama) ranged from 37 to 47%, respectively; colonies with gonads from upwelling environments (Saboga and Taboga Islands, Panama) ranged from 31 to 39%, respectively, and reproductively active colonies from the thermally variable Galapagos islands comprised 40% of the collections. Compared with P. gigantea, the numbers of sexually active G. planulata colonies were roughly onehalf at nonupwelling Cano Island (20%) and Uva Island (25%) sites, or less (10%) at the upwelling Saboga Island site. Peak reproductive activity in P. gigantea occurred during the rainy season at all study sites. In the nonupwelling Costa Rican (Cano Island) and Panamainan (Uva Island) sites, mean monthly sea-surface temperatures (SSTs) were high (28 to 29°C), but slightly lower than in the dry season (29°C). In the upwelling Gulf of Panama (Saboga and Taboga Islands), reproduction occurred after mean monthly SSTs increased from 24 to 28–29°C. In the Galapagos Islands, reproductive activity peaked during sea warming, when mean monthly SSTs reached 25°C. Sexually active colonies of G. planulata, present only at the main collection sites of Cano and Uva Islands, were also observed during the wet season. The presence of mature or spawned gonalds in both species mostly around new and full lunar phases suggests that spawning is at least weakly synchronized with moon phase. Fecundity estimates disclosed the following nonsignificant differences between sites for P. gigantea, expressed as egg production cm-2 colony surface surface yr-1: Galapagos (10 300 to 30 800), Uva Island (4900 to 9800), Cano Island (1800 to 7400), Saboga Island (600 to 1300) Taboga Island (1200 to 2400). Fecundity estimates for G. planulata were considerably lower: Uva Island (700 to 1400), Cano Island (500 to 1000). The sexual recruitment of P. gigantea into El Nino-Southern Oscillation (ENSO) 1982–1983-disturbed, equatorial eastern Pacific coral communities has been low, with only moderate recovery evident since 1983. G. planulata has revealed no sexual recruitment where seed populations are absent or rare (Cano Island, Galapagos Islands), and only low recruitment (Panama) in areas with colonies that survived the ENSO disturbance.