RESUMEN

Introduction: The litterfall production, foliar nutrient dynamics and decomposition are essential to maintain nutrient cycling, soil fertility, and carbon regulation in terrestrial ecosystems. With several studies addressing the variation of these processes, their dynamics in tropical dry forests (TDFs) remain unclear, due to its complex interaction of biotic and abiotic factors. Objective: To evaluate litterfall, nutrient potential return and use efficiency, and decomposition variation in a TDF successional gradient in Tolima, Colombia. Methods: We quantified litterfall from November 2017 to October 2019 in 12 plots distributed in four successional stages: initial, early, intermediate, and late forests. We identified key tree species in foliar litter production and characterized the foliar decomposition of these species. At the community level, we quantified the C, N and P potential return, the N and P use efficiency, and the C:N and N:P ratio. Subsequently, we analyze relationships between vegetation characteristics and some soil chemical properties with these ecological processes. Results: We found that total litterfall in late forests (8.46 Mg ha-1 y-1) was double that found in initial forests (4.45 Mg ha-1 y-1). Decomposition was higher in initial (k = 1.28) compared to intermediate (k = 0.97) and late forests (k = 0.87). The nutrient potential return didn't change along succession, but it did show differences between study sites. The structural development and species richness favored litterfall, while soil chemical conditions influenced nutrient returns and decomposition. Conclusions: TDFs could recover key ecosystem function related to litterfall and nutrient dynamics after disturbances cessation; however, the soil quality is fundamental in return and release of nutrients.

Introducción: La producción de hojarasca, la dinámica de nutrientes foliares y la descomposición son esenciales para mantener el ciclo de nutrientes, la fertilidad del suelo y la regulación del carbono en ecosistemas terrestres. Con diversos estudios que abordan estos procesos, su variación en los bosques secos tropicales (BSTs) permanece incierta, por su compleja interacción de factores bióticos y abióticos. Objetivo: Evaluar la caída de hojarasca, el retorno potencial de nutrientes y eficiencia de uso, y la variación en descomposición en un gradiente sucesional de un BST en Tolima, Colombia. Métodos: Cuantificamos la caída de hojarasca entre noviembre 2017 y octubre 2019 en 12 parcelas distribuidas en cuatro estados sucesionales: bosque inicial, temprano, intermedio y tardío. Identificamos las especies arbóreas clave en la producción de hojarasca y caracterizamos la descomposición foliar de estas especies. A nivel comunitario, cuantificamos el retorno potencial de C, N y P, la eficiencia de uso de N y P y la relación C:N y N:P. Posteriormente, analizamos las relaciones entre las características de la vegetación y algunas propiedades químicas del suelo con estos procesos ecológicos. Resultados: Encontramos que la caída total de hojarasca en los bosques tardíos (8.46 Mg ha-1 año-1) fue el doble de la hallada en bosques iniciales (4.45 Mg ha-1 año-1). La descomposición fue mayor en bosques iniciales (k = 1.28) en comparación con bosques intermedios (k = 0.97) y tardíos (k = 0.87). El retorno potencial de nutrientes no cambió con el avance de la sucesión vegetal, pero exhibió diferencias entre los sitios de estudio. El desarrollo estructural y la riqueza de especies favorecieron la caída de hojarasca, mientras que las condiciones químicas del suelo influyeron en el retorno de nutrientes y descomposición. Conclusiones: Los BSTs tienen la capacidad de recuperar la función ecosistémica de aporte de hojarasca fina, retorno y liberación de nutrientes después del cese de alteraciones antrópicas; sin embargo, la calidad del suelo es fundamental en el retorno y liberación de nutrientes.

Asunto(s)

RESUMEN

The authors experimentally demonstrated that an aqueous fraction of Drymonia serrulata (Jacq.) Mart. has peripheral, but not central, analgesic activity, and that it also has a dose-dependent anti-inflammatory activity at 24 and 96 hours. The experimental results indicate that the etnomedical use of this plant by the Guaymi Indians may have some scientific validity

Asunto(s)

RESUMEN

The authors experimentally demonstrated that an aqueous fraction of Drymonia serrulata (Jacq.) Mart. has peripheral, but not central, analgesic activity, and that it also has a dose-dependent anti-inflammatory activity at 24 and 96 hours. The experimental results indicate that the etnomedical use of this plant by the Guaymi Indians may have some scientific validity

Asunto(s)

RESUMEN

Efforts are being made to extend the practice of Community Oriented Primary Care by reorienting existing health services or restructuring medical education curricula. Nevertheless, changes in education must be simultaneous to changes in health services so that health professionals trained in COPC will find areas to practice COPC. The experience described in this article presents an effort in these two directions. A teaching program was introduced in a traditional medical school curriculum and was extended to six health services by training the directors of the health service as teaching instructors of COPC or closely coordinating actions with the director of the health service. The results of the program show fulfillment of learning objectives and student satisfaction with the program. Evaluations of the development of COPC in the health services involved show modifications in health programs to meet community needs and stronger community leadership and organization.

PIP: Community Oriented Primary Care (COPC) emphasizes the individual and family and special needs population within a community setting in conformity with the Alma Ata Declaration of Health for All. The experiences of implementing COPC within the curriculum in a traditional medical school in Bogota, Colombia, are related. Training was also conducted in 3 urban and 3 rural locations, which were government health providers of primary care, influenced by a university close by, and had a committed, general practitioner available. Evaluations of students' perceptions of the course and the development of COPC were performed. The traditional medical school was the Jesuit-run Javeriana University, which was founded in 1942; the Department of Preventive Medicine and Social Medicine was restructured after 1984 due to evaluations which showed limited learning and negative attitudes. During the planning phase, the COPC theoretical model was defined, general learning objectives were identified, and teaching strategies selected. The COPC model was chosen because it integrated clinical with community practice and epidemiology with health services administration. Community participation was viewed as a mean to empower people through validating people's knowledge, broadening access to information and establishing cooperative relationships between health professionals and the people. The 10-week training program engaged 8 groups of 35 students during the initial 2 years of operation. Each group under the supervision of a tutor carried out a different phase of COPC. Care was both preventive and curative; programs were developed to modify risk factors for diarrheal disease, malnutrition, and respiratory disease. Participatory research is being conducted in 6 communities. The results of the students' evaluations show satisfaction with the program and learning objectives. Attitudes among students were changed, but whether these changes will continue into professional practice is unknown. The impact on health services showed that health programs were changed to reflect community needs; stronger community leadership and organization evolved. Problems were identified as lack of understanding of COPC applications, staff turnover, motivation, scarce resources, and people's attitudes of fatalism and paternalistic services.

Asunto(s)

RESUMEN

The authors report the results of pharmacologic evaluation of two medicinal plants: Cajanus cajan (L.) Millsp and Cassia fistula, which are used in Panamanian folk medicine for the treatment of diabetes. It was found that the aqueous fraction of the leaves and stems of C. cajan did not produce any hypo blood sugar effect in normoglycemic mice; instead, it produced a hyperglycemia with doses of 500 mg/kg and 1000 mg/kg (p less than 0.001). Only with a dose of 300 mg/kg a short lived decrease in the glycemia was seen at one hour. On the contrary, the folk use of the leaves of C. fistula for diabetes seems to have some correlation with the popular frek use. The aqueous fraction produced a significant decrease in the glycemia (p less than 0.001) at 4 and 24 hours with doses of 300 and 500 mg/kg, and at one and four hours after the dose of 1000 mg/kg (p less than 0.001). In the glucose tolerance test, the aqueous fraction of C. cajan produced a significant and short lasting decrease (p less than 0.05) with the dose of 300 mg/kg, while the dose of 500 mg/kg did at 0.25, 0.5 and 1 hour (p less than 0.01). The 1000 mg/kg dose produced a significant increase in glucose tolerance at 1 and 2 hours (p less than 0.05). The aqueous fraction of C. fistula produced a significant decrease (p less than 0.05) with the dose of 500 mg/kg at 0.25 and 0.5 hours. The 1000 mg/kg dose produced a significant increase (p less than 0.001) at 0.25 and 2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)