Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

Copyright © 2009 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/6/2759/2009/bg-6-2759-2009.html © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License.The net primary productivity (NPP) of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1) How do Amazonian forests allocate productivity among its above- and below-ground components? (2) How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3MgC ha−1 yr−1 (mean±standard error), at a white sand plot, and 17.0±1.4MgC ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9MgC ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content

Características clínicas de pacientes internados en el Hospital de Apoyo de Iquitos "César Garayar García" durante la epidemia de dengue, enero-febrero de 2011

We conducted a clinical description of confirmed dengue cases admitted to the Hospital “ César Garayar García” in Iquitos from January 25 to February 5, 2011. According to current WHO classification, major warning signs leading to hospitalization were: abdominal pain (28/28) and persistent vomiting (15/28), the causes of severity were: hypotension (9 / 13), severe bleeding (6 / 13) and plasma extravasation with respiratory distress (4 / 13). The median patient age was 22 years, however, 8 / 13 patients classified as severe dengue were under 16 years. In conclusion, unlike previous epidemics, we found a high involvement of young people and severity in the clinical presentation predominating a high frequency of shock (hypotension) and vascular leakage, which could be related to the circulation of an emerging variant DENV-2 which is more virulent.Se realizó una descripción clínica de pacientes con dengue confirmado internados en el Hospital de Apoyo de Iquitos “César Garayar García” desde el 25 de enero al 05 de febrero de 2011. Según la actual clasificación de la OMS, los principales signos de alarma que motivaron hospitalización fueron: dolor abdominal (28/28) y vómitos persistentes (15/28); las causas de gravedad fueron: hipotensión (9/13), sangrado grave (6/13) y extravasación de plasma con dificultad respiratoria (4/13). La mediana de edad de los pacientes fue 22 años, sin embargo, 8/13 pacientes clasificados como dengue grave fueron menores de 16 años. En conclusión, se evidencia una mayor afectación de la población joven y gravedad en la presentación clínica a diferencia de epidemias anteriores, predominando el shock (hipotensión) por extravasación vascular, lo cual podría estar relacionado con la circulación de una variante emergente del DENV-2 con mayor virulencia