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Measurements of net primary productivity (NPP) and litter decomposition from tropical peatlands are severely lacking, limiting our ability to parameterise and validate models of tropical peatland development and thereby make robust predictions of how these systems will respond to future environmental and climatic change. Here, we present total NPP (i.e., above- and below-ground) and decomposition data from two floristically and structurally distinct forested peatland sites within the Pastaza Marañón Foreland Basin, northern Peru, the largest tropical peatland area in Amazonia: (1) a palm (largely Mauritia flexuosa) dominated swamp forest and (2) a hardwood dominated swamp forest (known as 'pole forest', due to the abundance of thin-stemmed trees). Total NPP in the palm forest and hardwood-dominated forest (9.83 ± 1.43 and 7.34 ± 0.84 Mg C ha-1 year-1, respectively) was low compared with values reported for terra firme forest in the region (14.21-15.01 Mg C ha-1 year-1) and for tropical peatlands elsewhere (11.06 and 13.20 Mg C ha-1 year-1). Despite the similar total NPP of the two forest types, there were considerable differences in the distribution of NPP. Fine root NPP was seven times higher in the palm forest (4.56 ± 1.05 Mg C ha-1 year-1) than in the hardwood forest (0.61 ± 0.22 Mg C ha-1 year-1). Above-ground palm NPP, a frequently overlooked component, made large contributions to total NPP in the palm-dominated forest, accounting for 41% (14% in the hardwood-dominated forest). Conversely, Mauritia flexuosa litter decomposition rates were the same in both plots: highest for leaf material, followed by root and then stem material (21%, 77% and 86% of mass remaining after 1 year respectively for both plots). Our results suggest potential differences in these two peatland types' responses to climate and other environmental changes and will assist in future modelling studies of these systems.

Mediciones de la productividad primaria neta (PPN) y la descomposición de materia orgánica de las turberas tropicales son escasas, lo que limita nuestra capacidad para parametrizar y validar modelos de desarrollo de las turberas tropicales y, en consecuencia, realizar predicciones sólidas sobre la respuesta de estos sistemas ante futuros cambios ambientales y climáticos. En este estudio, presentamos datos de PPN total (es decir, biomasa aérea y subterránea) y descomposición de la materia orgánica colectada en dos turberas boscosas con características florísticas y estructurales contrastantes dentro de la cuenca Pastaza Marañón al norte del Perú, el área de turberas tropicales más grande de la Amazonia: (1) un bosque pantanoso dominado por palmeras (principalmente Mauritia flexuosa) y (2) un bosque pantanosos dominado por árboles leñosos de tallo delgado (conocido como 'varillal hidromórfico'). La PPN total en el bosque de palmeras y el varillal hidromórfico (9,83 ± 1,43 y 7,34 ± 0,84 Mg C ha­1 año­1 respectivamente) fue baja en comparación con los valores reportados para los bosques de tierra firme en la región (14,21­15,01 Mg C ha­1 año­1) y para turberas tropicales en otros lugares (11,06 y 13,20 Mg C ha­1 año­1). A pesar de que la PPN total fue similar en ambos tipos de bosque, hubo diferencias considerables en la distribución de la PPN. La PPN de las raíces finas fue siete veces mayor en el bosque de palmeras (4,56 ± 1,05 Mg C ha­1 año­1) que en el varillal hidromórfico (0,61 ± 0,22 Mg C ha­1 año­1). La PPN de la biomasa aérea de las palmeras, un componente ignorado frecuentemente, contribuyó en gran medida a la PPN total del bosque de palmeras, representando el 41% (14% en el varillal hidromórfico). Por el contrario, la tasa de descomposición de materia orgánica de Mauritia flexuosa fue la misma en ambos sitios: la más alta corresponde a la hojarasca, seguida por las raíces y luego el tallo (21%, 77% y 86% de la masa restante después de un año, respectivamente para ambos sitios). Nuestros resultados sugieren diferencias potenciales en la respuesta de estos dos tipos de turberas al clima y otros cambios ambientales, y ayudarán en futuros estudios de modelamiento de estos sistemas.

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The estimation of human ankle's mechanical impedance is an important tool for modeling human balance. This work presents the implementation of a parameter-estimation approach based on a state-augmented extended Kalman filter (AEKF) to infer the ankle's mechanical impedance during quiet standing. However, the AEKF filter is sensitive to the initialization of the noise covariance matrices. In order to avoid a time-consuming trial-and-error method and to obtain a better estimation performance, a genetic algorithm (GA) is proposed to best tune the measurement noise (Rk) and process noise covariances (Q) of the extended Kalman filter (EKF). Results using simulated data show the efficacy of the proposed algorithm for parameter-estimation of a third-order biomechanical model. Experimental validation of these results is also presented. They suggest that age is an influencing factor in the human balance.

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The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.

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Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza-Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land-use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon-dense (domed pole forest) areas. New carbon-based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.

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Objectives of this study were: (a) to compare live weight (LW) and zoometric measures (ZM) of local goats in two locations, (b) to fit the best regression equation for goat LW prediction using ZM. LW, body length (BL), trunk length (TL), withers height (WH), hearth girth (HG), rump width (RW), rump length (RL), head length (HL), head width (HW), and ear length (EL) were measured in 318 Local does in Amatepec and Tejupilco, State of Mexico. Statistical methods included student's "t" tests for comparison of means, and correlation, principal components (PC), and multiple linear regression analyses. To evaluate the goodness of fit for LW prediction models the R(2) value was used as a criterion. Differences (P ≤ 0.05) were found between does of Amatepec and Tejupilco in LW, BL, TL, HG, RL, HL, HW, and EL. In Amatepec, LW was correlated with HG, BL, and HW (P ≤ 0.01), whereas in Tejupilco LW was correlated with HG, BL, TL, and HW (P ≤ 0.01). From the Amatepec measures 5 PC were extracted, and which in a multiple regression analysis explained 83.3 % of the total variance, whereas from Tejupilco 4 PC were extracted, and which in a multiple regression analysis explained 82.4 % of the total variance. The best regression model to predict doe LW in Amatepec included TL, HG, RW, and HW, whereas for Tejupilco the best model included BL, HG, HW, and EL. It is concluded that: (1) Amatepec does surpass those of Tejupilco in LW and most ZM, (2) there are reliable ZM for predicting LW of local does in both locations, HG, and HW being common measures for both populations.

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Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

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The morphological stability/morphological reshaping of noble metal nanoparticles are studied experimentally in order to unravel the chemical mechanisms lying beneath. Gold and silver nanoparticles (AuNPs and AgNPs, respectively) formed in chloroformic environment are used, as model synthetic systems, to study phenomena of morphological change. The morphological evolution of NPs that follows their formation, is characterized by spectroscopy (UV-Visible, Raman and FTIR) and TEM (Transmission Electron Microscopy). The change of NP morphology involves the increase of the average NP size and the broadening of size distribution, in a close resemblance with the effect characteristically obtained from the Ostwald ripening. The effect of the poor solvating properties of chloroform in stabilizing small charged species (H+, Ag+, Au+) as well as the principle of electroneutrality of matter are analyzed in order to formulate a feasible reaction scheme consisting of a three-step processes: the generation of soluble intermediary species by corrosion of nanoparticles, the diffusion of intermediary species from one nanoparticle to another, and the re-deposition process involving the reduction of intermediary species. This basic reaction scheme is used as hypothesis to plan and perform experiments, which reveal that molecular oxygen dissolved in the dispersive medium can drive NP corrosion, however, protic species are also required as co-reactant. The polarity of the hydrogen bond and the ligand properties of the anions produced by deprotonation are feature of the protic species that enable/disable the corrosion and, in turn, the NP morphological evolution.

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A two-phase anaerobic digestion process of synthetic domestic wastewater was studied at ambient temperature in mild to cold climates. The hydrolytic stage was carried out in a continuous stirred tank reactor with an effective volume of 1.2 L. The hydrolytic reactor operated at hydraulic retention times (HRTs) in the range of 1.3 to 2.7 h, which allowed for optimum HRT to be obtained in order to achieve a maximum amount of soluble COD. For the methanogenic stage, an up-flow anaerobic filter with a volume of 1.35 L and corrugated plastic rings as biomass immobilization support were used. During the investigation, the ambient temperature ranged between 21 degrees C and 24 degrees C. Synthetic domestic wastewater with a COD of 700 mg/L was used as substrate. The study was performed at total organic loading rates (OLR(T)) of 2.0-4.3 g COD/L. d, with a global HRT (including both hydrolytic and methanogenic stages) of 2.8-5.8 hours. A maximum percentage of organic matter removed of 88% was achieved at a global HRT of 5.8 hours. Under these operating conditions, the production of biogas was 97% higher than that obtained in the one-phase anaerobic digestion process. Additionally, the kinetics involved in the hydrolytic stage was determined using the Contois kinetic model, which adequately predicted the experimental results.

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La magnitud, velocidad y eficacia antihipertensiva de la nifedipina de liberación programada en microgránulos (NLPM) fue evaluada en pacientes con hipertensión moderada a severa. Un total de ciento treinta y cinco pacientes fueron evaluados durante seis semanas en un estudio prospectivo, abierto, comparativo y cruzado. 25.9% (n = 35) fueron pacientes controles normales, del resto eran pacientes hipertensos, 40% (n = 54 pacientes) recibieron 30 mgrs (8am ó 8pm) de NLPM y 20.7% (n = 28 pacientes) recibieron 60 mgrs (8am ó 8pm) de NLPM, el 13.3% de los pacientes admitidos (n = 18) fueron considerados como fracasos de la medicación. Ambas dosis a los distintos horarios de la toma disminuyeron significativamente las presiones arteriales (p < 0.05). En los pacientes que lograron el punto deseado con 30 mgrs, éste se logró desde la 3ra. semana de administrado el medicamento manteniéndose en los niveles tensionales buscados hasta el final del estudio, siendo la magnitud más elevada de reducción de: 8am PAS 15.5 mmHg (12.2%), PAD 12 mmHg (12.6%), PAM 12.2 mmHg (10.9%) y 8pm de: PAS 14.1 mmHg (9.7%), PAD 9.5 mmHg (10.6%) y PAM 11.2 mmHg (10.05%), en cambio en aquellos que lograron el punto deseado con la administración de 60 mgrs, se observaron reducciones desde la 3ra. semana obteniéndose el efecto máximo a la 6ta.semana siendo la magnitud más elevada de reducción de: 8am PAS 26.3 mmHg (16.34%), PAD 18.5 mmHg (17.69%) y PAM 20.9 mmHg (17.0%) y 8pm PAS 22.5 mmHg (15.15%), PAD 18 mmHg (18.1%) y PAM 21.8 mmHg (18.5%). La magnitud de la respuesta antihipertensiva de la NLPM fue numéricamente mayor con 60 mgrs que con 30 mgrs, pero la velocidad de respuesta fue mayor con 30 mgrs probablemente debido a que las cifras tensionales al inicio del estudio eran mayores en el grupo que requirió 60 mgrs, (p < 0.05) llegándose al final del estudio (6ta. semana) a cifras tensionales normales y similares en ambos grupos (p > 0.05). La FC en el grupo de 30 mgrs (8am y 8pm) mostró una disminución significativa luego del tratamiento (p < 0.05), en cambio en el grupo de 60 mgrs éstas se mantuvieron inalteradas (p > 0.05). En conclusión NLPM demostró ser eficaz para el manejo de los pacientes con hipertensión leve a moderada, obteniéndose con la dosis de 60 mgrs mayor magnitud en el efecto hipotensor que con la dosis de 30 mgrs, exhibiendo esta última mayor velocidad de respuesta antihipertensiva.

The magnitude, velocity and antihypertensive effectiveness of the nifedipine liberation programmed in microgranules (NLPM) was evaluated in patients with moderate to severe hypertension. A total of one hundred and thirty five patients were evaluated during six weeks in a prospective, open, comparative and crossed study. Of that group, 25.9% (n = 35) were normal patients, the remainder of them were hypertensive patients, 40% (n = 54 patients) received 30 mgrs (8am or 8pm) of NLPM and 20.7% (n = 28 patients) received 60 mgrs (8am or 8pm) of NLPM, 13.3% of the admitted patients (n = 18) were considered as failures of the medication. Both doses at different schedules of the taking diminished the arterial pressures significantly (p <0.05). There were patients that reached the end point a 30 mgrs dose, this achievement was obtained from the 3rd week of medication keeping on these pressure levels until the end of the study, being the highest magnitude of reduction were: 8am PAS 15.5 mmHg (12.2%), PAD 12 mmHg (12.6%), PAM 12.2 mmHg (10.9%) and 8pm of: PAS 14.1 mmHg (9.7%), PAD 9.5 mmHg (10.6%) and PAM 11.2 mmHg (10.05%), on the other hand, in those who achieved the end point with the administration of 60 mgrs, reductions were observed from the 3rd week obtaining the maximum effect at the 6th week being the highest magnitude of reduction of: 8am PAS 26.3 mmHg (16.34%), PAD 18.5 mmHg (17.69%) and PAM 20.9 mmHg (17.0%) and 8pm PAS 22.5 mmHg (15.15%), PAD 18 mmHg (18.1%) and PAM 21.8 mmHg (18.5%). The magnitude of the antihypertensive response of the NLPM was numerically bigger with 60 mgrs than with 30 mgrs, but the response velocity was bigger with 30 mgrs maybe because the blood pressure at the beginning of the study were bigger in that group that required 60 mgrs, (p <0.05) arriving at the end of the study (6th week) to normal pressure figure, similar in both groups (p> 0.05). The heart rate in the group of 30 mgrs (8am and 8pm) showed a significant decrease after the treatment (p <0.05), on the other hand in the group of 60 mgrs these stayed unaffected (p> 0.05). In conclusion NLPM demonstrated to be effective for the managing of patients with light to moderate hypertension, obtaining a bigger magnitude in the blood pressure effect with a dose of 60 mgrs than with a dose 30 mgrs, however, with this last dose, the antihypertensive response was more fast.

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The arrival of the new millennium move us to make a series of reflections about the status of Science and Technology in Venezuela and consequently, in Latin America. It seems that we have not understood yet, that having strong Science and Technology put us in a more advantageous position to cope with the problems related to our underdevelopment. Decisive and expeditious actions are required in Venezuela and Latin America to reduce the scientific and technological gap between developed and underdeveloped countries. These actions can be portrayed in two possible scenarios. The first one, dealing with scientific funding of basic and applied research focused on areas of critical need. Central, regional and local governments must share responsibilities for scientific development and hence, to provide appropriate funding for scientific research. The financing of personnel and the acquisition of equipment and materials for qualified scientists and research centers should be guaranteed. The second scenario deals with universities and superior education institutions which should match their curricula to contemporaneous knowledge, and to assume their role as science promoters through a creditable scientific leadership. Also, they must provide affordable opportunities for teachers and scientists to catch up with the continuing and progressive advance of science, through the establishment of inter-institutional agreements in Venezuela and abroad which would allow Venezuelan scientists to participate in joint research ventures, and therefore, to be in touch with knowledge and technologies not available in our countries.

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El presente trabajo tiene por objeto determinar si existe alguna relación entre el nivel socio-económico (NSE) de pacientes y la colonización del estómago por el Campylobacter pilórico (CP). Estudiamos diversos aspectos de esta bacteria en dos grupos de pacientes de NSE diferente, nos pareció de inicio apreciar una aparente diferencia en relación a la colonización del estómago por esta bacteria. Hemos evaluado 256 pacientes examinados mediante esofagogastroduodenoscopía (Panendocopio Olympus GIF-K2) por presentar síntomas del tracto gastrointestinal superior. De ellos, 143 pertenecen al Hospital Arzobispo Loayza (38 varones y 105 mujeres) y 122 a la práctica privada de 3 de los autores (77 varones y 45 mujeres), con edades comprendidos entre 16 y 75 años (media de 45.5 años). En cada caso se tomó biopsias del antro gástrico (curvatura mayor y menor) las que fueron coloreadas con hematoxilina-eosina y con plata. Tomando en cuenta recomendaciones para clasificar el NSE de acuerdo a la procedencia los pacientes fueron considerados habitantes de: distritos nucleares, distitos intermedios y distritos periféricos. Los cálculos estadísticas han revelado que aunque de acuerdo a la procedencia, los grupos de pacientes del Hospital Arzobispo Loayza y de la práctica privada tuvieron un NSE significativamente diferente, la frecuencia de infección por CP en ellos no mostró diferencia estadísticamente significativa. Lo cual parecería indicar pues, que el distrito del cual procede un paciente con trastornos del tracto gastrointestinal no es factor determinante de infección por CP (AU)

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El presente trabajo tiene por objeto determinar si existe alguna relación entre el nivel socio-económico (NSE) de pacientes y la colonización del estómago por el Campylobacter pilórico (CP). Estudiamos diversos aspectos de esta bacteria en dos grupos de pacientes de NSE diferente, nos pareció de inicio apreciar una aparente diferencia en relación a la colonización del estómago por esta bacteria. Hemos evaluado 256 pacientes examinados mediante esofagogastroduodenoscopía (Panendocopio Olympus GIF-K2) por presentar síntomas del tracto gastrointestinal superior. De ellos, 143 pertenecen al Hospital Arzobispo Loayza (38 varones y 105 mujeres) y 122 a la práctica privada de 3 de los autores (77 varones y 45 mujeres), con edades comprendidos entre 16 y 75 años (media de 45.5 años). En cada caso se tomó biopsias del antro gástrico (curvatura mayor y menor) las que fueron coloreadas con hematoxilina-eosina y con plata. Tomando en cuenta recomendaciones para clasificar el NSE de acuerdo a la procedencia los pacientes fueron considerados habitantes de: distritos nucleares, distitos intermedios y distritos periféricos. Los cálculos estadísticas han revelado que aunque de acuerdo a la procedencia, los grupos de pacientes del Hospital Arzobispo Loayza y de la práctica privada tuvieron un NSE significativamente diferente, la frecuencia de infección por CP en ellos no mostró diferencia estadísticamente significativa. Lo cual parecería indicar pues, que el distrito del cual procede un paciente con trastornos del tracto gastrointestinal no es factor determinante de infección por CP

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Diversos trabajos demuestram un elevado porcentaje de hallazgo del campylobacter pilórico en casos de gastritis crónica y úlcera péptica. Presentamos nuestra experiencia en 672 pacientes evaluados mediante esofagogastroduodenoscopía, por presentar síntomas del tracto gastrointestinal superior. Se utilizó el Panendoscopio Olympus GIF-k2 tomándose dos biopsias del antro gástrico. Los especimenes fueron sometidos a coloración con hematoxilinaeosina y con plata, métodos que nos han dado los mejores resultados diagnósticos. El diagnóstico de úlcera gástrica o duodenal se hizo sobre la base del hallazgo endoscópico y para el diagnóstico de gastritis crônica se consideró el criterio histológico. La gastritis se ha dividido en activa e inactica. Se ha cuantificado el daño mucinoso y el grado colonización bacteriana. Hemos encontrado a la bacteria en el 91.8% de pacientes con gastritis crónica activa, 72.7% con úlcera gástrica y 84.2% con úlcera duodenal. Nuestros resultados sosn concordantes con los de otros autores. Concluimos que el campylobacter pilórico no es un germen oportunista en el estómago, pues produce cuadro inflamatorio y daño celular mucinoso. Su presencia puede jugar algún rol en la etiopatogenia de la úlcera péptica y gastritis

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After the initial report of Marshall and Warren, several publications have also demonstrated the presence of pyloric campylobacter in an elevated percentage of cases of chronic gastritis and peptic ulcer. We present our experience studying 672 patients examined by esophagogastroduodenoscopy after referral to clinical because of upper gastrointestinal symptoms. We used an Olympus GIF-K2 panendoscope taking two biopsies from the gastric antrum. Specimens were stained with hematoxilin-eosin and silver. In our experience these methods have given us the best results in detecting this bacteria. Diagnosis of gastric and duodenal ulcer was made by endoscopic criteria and chronic gastritis diagnosed by histology. Chronic gastritis was categorized into active and inactive based in the invasion of polymorphonuclear into mucosa. We have also quantitated damage of the mucin producing cells as well as the degree of bacterial colonization. We have found pyloric campylobacter in 91.8% of patients suffering from chronic active gastritis, 72.7% of patients with diagnosis of gastric ulcer and 84.2% of cases of duodenal ulcer. Our results agree with the ones reported by other authors. We conclude that pyloric campylobacter is not an opportunist microorganism within the stomach because it produces inflammatory changes as well as damage of the mucin producing cells. Its presence may play some role in the etiology of gastritis and peptic ulcer disease.

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Se presentan 59 ninos con polipos de recto y colon. La manifestacion clinica principal fue hematoquezia. La gran mayoria de los ninos tuvieron un polipo. La localizacion mas frecuente de estos fue en los primeros 10 cm del rectosigmoides. El tacto rectal diagnostico una proporcion de 0.69%. En 56 pacientes, el polipo fue de tipo inflamatorio o juvenil desde el punto de vista histologico. Solo en dos ninos la reseccion de los polipos fue necesaria a trabes de colonoscopia

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