Neighborhood and community interactions determine the spatial pattern of tropical tree seedling survival

Factors affecting survival and recruitment of 3531 individually mapped seedlings of Myristicaceae were examined over three years in a highly diverse neotropical rain forest, at spatial scales of 1–9 m and 25 ha. We found convincing evidence of a community compensatory trend (CCT) in seedling survival (i.e., more abundant species had higher seedling mortality at the 25-ha scale), which suggests that density-dependent mortality may contribute to the spatial dynamics of seedling recruitment. Unlike previous studies, we demonstrate that the CCT was not caused by differences in microhabitat preferences or life history strategy among the study species. In local neighborhood analyses, the spatial autocorrelation of seedling survival was important at small spatial scales (1–5 m) but decayed rapidly with increasing distance. Relative seedling height had the greatest effect on seedling survival. Conspecific seedling density had a more negative effect on survival than heterospecific seedling density and was stronger and extended farther in rare species than in common species. Taken together, the CCT and neighborhood analyses suggest that seedling mortality is coupled more strongly to the landscape-scale abundance of conspecific large trees in common species and the local density of conspecific seedlings in rare species. We conclude that negative density dependence could promote species coexistence in this rain forest community but that the scale dependence of interactions differs between rare and common species

La enfermedad como metáfora del antipositivismo en La ciudad de los tísicos (1911) de Abraham Valdelomar

Estudia La ciudad de los tísicos (1911) de Abraham Valdelomar bajo un marco de intercomprensión de la filosofía positivista, donde se vislumbran nuevas vías de estudio sobre la nouvelle valdelomariana y su relación con la política higienista estatal o las estrategias que utilizan los sujetos marginados (enfermos) para tratar de resistir o subvertir al discurso oficial del progreso que es propugnado por los ciudadanos

Incidencia, tratamiento y seguimiento para paraganglioma del cuerpo carotideo enel Hospital Nacional Carlos Alberto Seguín Escobedo 2012-2020

El paraganglioma del cuerpo carotideo, es una tumoración benigna, bastante rara, cuya incidencia es mayor en zonas de altura de más de 2000msnm, tal como la ciudad de Arequipa. El tratamiento de elección es la exceresis subadventicial del mismo mediante cirugía, la cual es de extrema dificultad por la ubicación, su intimo contacto con la arteria carótida y la cantidad de elementos vasculonerviosos que se encuentran en su cercanía y el gran riesgo de sangrado, habitualmente la tumoración es resecada sin mayores complicaciones. El objetivo principal de esta investigación es determinar la incidencia, el tratamiento y seguimiento del paraganglioma del cuerpo carotideo en el Hospital Nacional Carlos Alberto Seguin Escobedo en la ciudad de Arequipa desde el año 2012 hasta al año 2020.Proyecto de Investigació

ADHERENCIA A AGENTES ANTIHIPERTENSIVOS EN PACIENTES HEMODIALIZADOS: FRECUENCIA Y FACTORES RELACIONADOS EN DOS HOSPITALES. AREQUIPA 2015

INSUFICIENCIA RENAL CRÓNICA PROBLEMA EN SALUD ETIOLOGÍA EPIDEMIOLOGÍA FISIOPATOLOGÍA ETAPAS DE LA INSUFICIENCIA RENAL CUADRO CLÍNICO CAUSAS DE MORTALIDAD COMPLICACIONES Y CONSECUENCIAS DE LA ENFERMEDAD RENAL CRÓNICA TRATAMIENTO AGENTES ANTIHIPERTENSIVOS OTRO FÁRMACOS REDUCCIÓN DE LA INGESTA PROTEICA Y OTRAS MEDIDAS DIETÉTICAS DIÁLISIS TRASPLANTE RENAL HIPERTENSIÓN ARTERIAL E INSUFICIENCIA RENAL CRÓNICA EFECTO DEL TRATAMIENTO DE LA HIPERTENSIÓN ARTERIAL SOBRE LA FUNCIÓN RENAL EFECTOS CRÓNICOS EFECTOS AGUDO

Palms, peccaries and perturbations: widespread effects of small-scale disturbance in tropical forests

<p>Abstract</p> <p>Background</p> <p>Disturbance is an important process structuring ecosystems worldwide and has long been thought to be a significant driver of diversity and dynamics. In forests, most studies of disturbance have focused on large-scale disturbance such as hurricanes or tree-falls. However, smaller sub-canopy disturbances could also have significant impacts on community structure. One such sub-canopy disturbance in tropical forests is abscising leaves of large arborescent palm (Arececeae) trees. These leaves can weigh up to 15 kg and cause physical damage and mortality to juvenile plants. Previous studies examining this question suffered from the use of static data at small spatial scales. Here we use data from a large permanent forest plot combined with dynamic data on the survival and growth of > 66,000 individuals over a seven-year period to address whether falling palm fronds do impact neighboring seedling and sapling communities, or whether there is an interaction between the palms and peccaries rooting for fallen palm fruit in the same area as falling leaves. We tested the wider generalisation of these hypotheses by comparing seedling and sapling survival under fruiting and non-fruiting trees in another family, the Myristicaceae.</p> <p>Results</p> <p>We found a spatially-restricted but significant effect of large arborescent fruiting palms on the spatial structure, population dynamics and species diversity of neighbouring sapling and seedling communities. However, these effects were not found around slightly smaller non-fruiting palm trees, suggesting it is seed predators such as peccaries rather than falling leaves that impact on the communities around palm trees. Conversely, this hypothesis was not supported in data from other edible species, such as those in the family Myristicaceae.</p> <p>Conclusions</p> <p>Given the abundance of arborescent palm trees in Amazonian forests, it is reasonable to conclude that their presence does have a significant, if spatially-restricted, impact on juvenile plants, most likely on the survival and growth of seedlings and saplings damaged by foraging peccaries. Given the abundance of fruit produced by each palm, the widespread effects of these small-scale disturbances appear, over long time-scales, to cause directional changes in community structure at larger scales.</p

Spatially-Explicit Testing of a General Aboveground Carbon Density Estimation Model in aWestern Amazonian Forest Using Airborne LiDAR

Mapping aboveground carbon density in tropical forests can support CO2 emissionmonitoring and provide benefits for national resource management. Although LiDAR technology has been shown to be useful for assessing carbon density patterns, the accuracy and generality of calibrations of LiDAR-based aboveground carbon density (ACD) predictions with those obtained from field inventory techniques should be intensified in order to advance tropical forest carbon mapping. Here we present results from the application of a general ACD estimation model applied with small-footprint LiDAR data and field-based estimates of a 50-ha forest plot in Ecuador?s Yasuní National Park. Subplots used for calibration and validation of the general LiDAR equation were selected based on analysis of topographic position and spatial distribution of aboveground carbon stocks. The results showed that stratification of plot locations based on topography can improve the calibration and application of ACD estimation using airborne LiDAR (R2 = 0.94, RMSE = 5.81 Mg?C? ha?1, BIAS = 0.59). These results strongly suggest that a general LiDAR-based approach can be used for mapping aboveground carbon stocks in western lowland Amazonian forests

Seasonality of reproduction in an ever-wet lowland tropical forest in Amazonian Ecuador

We thank Pablo Alvia, Alvaro Pérez, Zornitza Aguilar, Paola Barriga, Matt Priest, Caroline Whitefoord, and Gorky Villa for assistance in collecting data or identifying species; Elina Gomez for entry of trap data; Hugo Navarrete, Katya Romoleroux and the QCA herbarium staff, and David Lasso and the ECY staff for help with logistics and needed permitting; Rick Condit, Elizabeth Losos, Robin Foster, and Henrik Balslev for initial encouragement to work within the Yasuní Forest Dynamics Plot; Hugo Romero for initially summarizing the YFDP and SSP weather data sets; Pablo Jarrin for setting up the TEAM weather station, and David Lasso and Carlos Padilla for maintaining that equipment and making the data available; and the Ecuadorian Ministerio del Ambiente for permission to work in Yasuní National Park [No 014-2019-IC-PNY-DPAO/AVS, No 012-2018-IC-PNY593-DPAO/AVS, No 008-2017-IC-PNY-DPAO/AVS, No 012-2016-IC-FAU-FLO-DPAO-PNY, No 594-014-2015-FLO-MAE-DPAO-PNY, and earlier permits]. The Forest Dynamics Plot of Yasuní National Park has been made possible through the generous support of the Pontifical Catholic University of Ecuador (PUCE) funds of donaciones del impuesto a la renta, the Government of Ecuador, the US National Science Foundation, the Andrew W. Mellon Foundation, the Smithsonian Tropical Research Institute, and the University of Aarhus of Denmark. The phenology project began while NCG was at the Natural History Museum, London, with funding (2000–2004) from the Department of Botany (NHM), the Andrew W. Mellon Foundation, British Airways, and the Natural Environment Research Council (GR9/04037). It continued with NCG at Southern Illinois University Carbondale (2005–2023). We thank the Center for Tropical Forest Science for transitional funding (2006–2008, 2017–2018) and the National Science Foundation LTREB program for long-term funding (2006–2020; DEB-0614525, DEB-1122634, DEB-1754632, DEB-1754668).Peer reviewedPublisher PD

Estudio experimental in situ para impermeabilizar en base a cal-arena-arcilla y mejorar la eficiencia de conducción del canal gochirca - tayabamba

La presente tesis tuvo como objetivo principal realizar un estudio experimental in situ para impermeabilizar en base a cal-arena-arcilla y mejorar la eficiencia de conducción del canal Gochirca-Tayabamba. El desarrollo del proyecto se realizó en tres etapas, la primera, consistió en calcular el caudal del canal mediante medición directa (método del cubo) siendo este de 4.61 L/s, hallar la pérdida de caudal del canal por infiltración siendo este de 1.41 L/s (30.56 % de caudal total), calcular la eficiencia de conducción hidráulica obteniendo un resultado de 69.41 % y determinar las diferentes proporciones del mortero hecho a base de arcilla, arena y cal, las cuales tuvieron las siguientes proporciones respectivamente: Muestra 1 (70%, 20%, 10%), muestra 2 (60%, 30%, 10%), muestra 3 (50%, 25%, 25%). En la segunda etapa para determinar las propiedades mecánicas de la arcilla y arena se realizó los ensayos en laboratorio obteniendo su clasificación respectivamente según SUCS arcilla de baja plasticidad (CL) y arena pobremente graduada (SP), y según la clasificación AASHTO material arcilloso A4 y material granular del grupo A-1-b; y por último se realizó el ensayo de infiltración cuyo proceso inició con la excavación in situ de 03 calicatas con una profundidad y diámetro de 0.30 m cada una, luego se revistió con el mortero en estudio con un espesor de 0.03 m, se agregó agua para observar y anotar 2 veces al día su descenso, el periodo de evaluación duró 8 semanas (56 días) y al final se analizó los resultados del ensayo y se determinó cual es la dosificación más eficiente contra la infiltración, siendo esta la muestra N°1 con una dosificación: 7:2:1. La tercera y última etapa, consistió en realizar el ensayo de infiltración en un tramo de canal de 2.8 m revestido con la mejor dosificación de mortero, primero se midió el caudal inicial (4.07 L/s) y final (3.93 L/s) del tramo sin revestimiento, luego se procedió a medir el caudal inicial (4.05 L/s) y final (4.04 L/s) del tramo revestido para determinar el nivel de infiltración del caudal, siendo este de 0.01 L/s; y finalmente se comparó con los resultados obtenidos de las mediciones hechas en el canal sin revestir, hallando así una eficiencia de 99.8 %. Se concluyó que se puede aumentar la eficiencia de conducción del agua de un canal impermeabilizándolo con el mortero con proporciones: 70 % arcilla, 20 % arena y 10 % cal, debido a que, la arcilla es un material con bajo nivel de permeabilidad, la arena ayuda para mejorar la consistencia y trabajabilidad, y la cal es un ligante natural siendo capaz de unir diferentes materiales y mejorando la adherencia de éstos.The main objective of this thesis was to carry out an experimental in situ study to waterproof the Gochirca-Tayabamba canal based on lime-sand clay and improve its conduction efficiency. The development of the project was carried out in three stages, the first, consisted in calculating the flow of the channel by means of direct measurement (bucket method) being this one of 4.61 L/s, to find the loss of flow of the channel by infiltration being this one of 1.41 L/s (30.56 % of total flow), to calculate the efficiency of hydraulic conduction obtaining a result of 69.41 % and to determine the different proportions of the mortar made with clay, sand and lime, which had the following proportions respectively: Sample 1 (70%, 20%, 10%), sample 2 (60%, 30%, 10%), sample 3 (50%, 25%, 25%). In the second stage to determine the mechanical properties of the clay and sand, laboratory tests were carried out, obtaining their classification respectively according to SUCS low plasticity clay (CL) and poorly graded sand (SP), and according to the AASHTO classification, clay material A4 and granular material of group A-1-b; and finally, the infiltration test was carried out, the process of which began with the excavation in situ of 03 calicatas with a depth and diameter of 0.30 m each, then coated with the mortar under study with a thickness of 0.03 m, water was added to observe and note twice a day its decline, the evaluation period lasted 8 weeks (56 days) and at the end the results of the test were analyzed and it was determined which is the most efficient dosage against infiltration, being this sample No. 1 with a dosage: 7:2:1. The third and last stage consisted of performing the infiltration test in a 2.8 m section of channel lined with the best mortar dosage, first the initial flow (4.07 L/s) and final flow (3.93 L/s) of the section without lining was measured, then proceeded to measure the initial flow (4.05 L/s) and final (4.04 L/s) of the lined section to determine the level of infiltration of the flow, being this of 0.01 L/s; and finally it was compared with the results obtained from the measurements made in the unlined channel, thus finding an efficiency of 99.8 %. It was concluded that it is possible to increase the water conduction efficiency of a waterproofing channel by using mortar with proportions: 70% clay, 20% sand and 10% lime, due to the fact that clay is a material with a low level of permeability, sand helps to improve consistency and workability, and lime is a natural binder being able to join different materials and improving their adherence.Tesi