Resistencia indígena y la evolución de fronteras en Rio Chinchipe, alto Marañon

ResumenEstudio histórico regional, en el cual se analiza la particularidad del pasado económico y político de la cuenca del río Chinchipe, demostrando que esta región ha sido, a lo largo de su historia, un objeto de contención política. La belicosa resistencia de la sociedad jíbara impuso condiciones particulares a las relaciones sociales de producción en esta zona de colonización agrícolaAbstractAnalysis of the economy and political history of Río Chinchipe Valley, and the reasons why this has been an area of political dispute. The Jíbaros`s bellicose resistence created especial conditions for the social relationship of production in this frontier area.

Los indígenas y la conservación de la Biodiversidad: 500 años de Resistencia

IntroducciónEn la actualidad, los indígenas costarricenses representan un 1% del total de la población de nuestro país. Sin embargo, este pequeño, pero importante sector de nuestra nación, ha podido conservar para sí, para los costarricenses y la humanidad, una parte importante del territorio deonde se resguarda nuestro patrimonio natural. Cerca del 85% de los indígenas vivien a ambos lados de la cordillera de Talamanca, asiento histórico de las dos etnias numéricamente más importantes de los indígenas costarricenses contemporáneos: los bribris y los cabécares. Aproximadamente el 75% del territorio es bosque natural y un 15% se encuentra en el presente literalmente alterado...

Conquista, colonización y resistencia indígena en Costa Rica

Introducciónla llegada de los europeos al continente americano causó gran impacto en las poblaciones indígenas, baste señañar el solo efecto que produjeron las enfermedades de origen europeo, desconocidas para los autóctonos americanos. entre los continentes de Europa, Asia y África, ya se había producido una "uniformidad microbiana", (debido a la existencia de contactos directos e indirectos), lo que llevó a que los habitantes de estos continentes desarrollaran inmunidad para resistir las enfermedades del Viejo Mundo. Por el contrario, América había quedado aislada desde las últimas oleadas migratorias de Asia a América, alrededor de 12.000 o más años atrás y en consecuencia al momento del descubrimiento las poblaciones americanas carecían de inmunidad biológica para enfrentar las enfermedades procedentes de Europa

CONSTRUCCIÓN SOCIAL DE LOS ESPACIOS DE PELIGROSIDAD E INSEGURIDAD EN EL SIGLO XXI. ESTUDIOS DE CASOS EN LA CIUDAD E RESISTENCIA. REPÚBLICA ARGENTINA

La problemática de la inseguridad delictiva, ha pasado a convertirse en una de las principales cuestiones no resueltas y en una prioridad para los gobiernos de América Latina, en los albores del siglo XXI. Con el propósito de exponer los mecanismos de identificación y configuración de los espacios estigmatizados en relación a la inseguridad y al riesgo delictivo, en barrios de la ciudad de Resistencia, capital de la provincia del Chaco, Argentina; la presente investigación propone indagar los procesos de conformación de espacios percibidos como inseguros, y estigmatizados socialmente por diferentes agentes sociales. La metodología empleada, de tipo inductiva y caracterizada por el predominio de técnicas cualitativas, supuso la realización de entrevistas en profundidad a funcionarios vinculados con la seguridad en la ciudad, encuestas de percepción espacial diferencial a ciudadanos y consulta documental en archivos de los principales medios periodísticos locales. Los aportes más relevantes de la investigación refieren a la identificación de espacios estigmatizados en relación a la inseguridad delictiva urbana e invitan a reflexionar sobre los modos de deconstrucción de tales estigmas.

Resistencia natural a estreptomicina e eficiência de estirpes de Rhizobium nativas nos cerrados associadas à Stylosanthes.

1983

Del infierno patriarcal a la resistencia activa: mi testimonio

Testimonio

La educación desde los pueblos indígenas de Bolivia. Análisis del proyecto de Nueva Ley de Educación “Avelino Siñani y Elizardo Pérez”, como resistencia frente a la educación para la globalización neoliberal

En este ensayo nos interesa abordar las implicaciones del cambio político y social que se vive en América Latina, particularmente enfocado en Bolivia y sobre la educación y su relación con el desarrollo, a partir del estudio del proyecto de Nueva Ley de Educación “Avelino Siñani-Elizardo Pérez”, presentado para su tramitación al Congreso Nacional por iniciativa del Gobierno de la República y del movimiento indígena-popular. Mediante la metodología del análisis de coyuntura y del análisis estructural temático del discurso, se busca mostrar de qué manera esta reforma construye formas de resistencia cultural y alternativas educativas ante la llamada educación para la globalización neoliberal, propia de un modelo de desarrollo económico impuesto a Bolivia hace más de 20 años.AbstractThis essay aims to find out on the implications of political and social changes currently in process in Latin America focusing in Bolivia’s education and development in the New Act in Education, Avelino Siñani-Elizardo Pérez. The bill of law was submitted to the National Congress by the Government of Bolivia and the Indigenous Popular Movement. Based on current situation analysis and in topic-structure discourse analysis as a methodological approach, it discourse analysis as a methodological approach, it endeavours to show how this reform may build cultural and alternative education as ways of resistance to the socalled education for the neliberal globalization. The latter is featured in the economic development model, imposed to Bolivia 20 years ago.

Numerical prediction of the lateral displacement capacity of flexural reinforced concrete shear walls

Previous earthquakes showed that shear wall damage could lead to catastrophic failures of the reinforced concrete building. The lateral load capacity of shear walls needs to be estimated to minimize associated losses during catastrophic events; hence it is necessary to develop and validate reliable and stable numerical methods able to converge to reasonable estimations with minimum computational effort. The beam-column 1-D line element with fiber-type cross-section model is a practical option that yields results in agreement with experimental data. However, shortcomings of using this model to predict the local damage response may come from the fact that the model requires fine calibration of material properties to overcome regularization and size effects. To reduce the mesh-dependency of the numerical model, a regularization method based on the concept of post-yield energy is applied in this work to both the concrete and the steel material constitutive laws to predict the nonlinear cyclic response and failure mechanism of concrete shear walls. Different categories of wall specimens known to produce a different response under in plane cyclic loading for their varied geometric and detailing characteristics are considered in this study, namely: 1) scaled wall specimens designed according to the European seismic design code and 2) unique full-scale wall specimens detailed according to the U.S. design code to develop a ductile behavior under cyclic loading. To test the boundaries of application of the proposed method, two full-scale walls with a mixed shear-flexure response and different values of applied axial load are also considered. The results of this study show that the use of regularized constitutive models considerably enhances the response predictions capabilities of the model with regards to global force-drift response and failure mode. The simulations presented in this thesis demonstrate the proposed model to be a valuable tool for researchers and engineers.

Influence Of Fluorescent Dye On Physical-mechanical Properties Of Luting Cements For Confocal Microscopy Analysis.

To evaluate the influence of a fluorescent dye (rhodamine B) on the physical and mechanical properties of three different luting cements: a conventional adhesive luting cement (RelyX ARC, 3M/ESPE), a self-adhesive luting cement (RelyX U-200, 3M/ESPE), and a self-etching and self-adhesive luting cement (SeT PP, SDI). The cements were mixed with 0.03 wt% rhodamine B, formed into bar-shaped specimens (n = 10), and light cured using an LED curing unit (Radii, SDI) with a radiant exposure of 32 J/cm(2) . The Knoop hardness (KHN), flexural strength (FS), and Young's modulus (YM) analyses were evaluated after storage for 24 h. Outcomes were subjected to two-way ANOVA and Tukey's test (P = 0.05) for multiple comparisons. No significant differences in FS or YM were observed among the tested groups (P ≥ 0.05); the addition of rhodamine B increased the hardness of the luting cements tested. The addition of a fluorescent agent at 0.03 wt% concentration does not negatively affect the physical-mechanical properties of the luting cement polymerization behavior.

Durabilidade de compósito biomassa vegetal-cimento modificado por polímero

The durability of the cellulose-cement composites is a decisive factor to introduce such material in the market. Polymers have been used in concrete and mortar production to increase its durability. The goal of this work was the physical and mechanical characterization of cellulose-cement composites modified by a polymer and the subsequent durability evaluation. The work also evaluated the dispersion of acrylic polymer in composites made of Pinus caribaea residues. The physical properties observed were water absorption by immersion and bulk density. Rupture modulus and toughness were determined by flexural test. The specimens were obtained from pads, produced by pressing and wet curing. Samples were subjected to accelerated aging tests by repeated wetting and drying cycles and hot-water bath and natural aging. The scanning electron microscopy (SEM) allowed verifying the fiber and composite characteristics along the time. For the composite range analyzed, it was observed the polymer improved the mechanical properties of composites besides a significant decreasing in water absorption. The use of polymer improved the performance of vegetable fiber-cement composites when compared to the conventional mortar, due to water absorption decreasing.

Influence of different catilever extensions and glass or polyamaramid reinforcement fibers on fracture strength of implant-supported temporary

In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey's test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.

Comparison of physical and mechanical properties of microwave-polymerized acrylic resin after disinfection in sodium hypochlorite solutions

This study evaluated the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin after immersion in sodium hypochlorite (NaOCl), simulating 20 min of disinfection daily during 180 days. Forty disk-shaped (15 x 4 mm) and 40 rectangular (65 x 10 x 3 mm) specimens were prepared with a microwave-polymerized acrylic resin (Onda-Cryl). Specimens were immersed in either 0.5% NaOCl, 1% NaOCl, Clorox/Calgon and distilled water (control). Color measurements were determined by a portable colorimeter. Three parallel lines, separated by 1.0 mm, were registered on each specimen before and after immersion procedures to analyze the surface roughness. The flexural strength was measured using a 3-point bending test in a universal testing machine with a 50 kgf load cell and a crosshead speed of 1 mm/min. Data were analyzed statistically by ANOVA and Tukey's test (?=0.05). There was no statistically significant differences (p>0.05) among the solutions for color, surface roughness and flexural strength. It may be concluded that immersion in NaOCl solutions simulating short-term daily use during 180 days did not influence the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin.

Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

Mechanical properties and porosity of dental glass-ceramics hot-pressed at different temperatures

The objective of this work was to evaluate biaxial-flexural-strength (σf), Vickers hardness (HV), fracture toughness (K Ic), Young's modulus (E), Poisson's ratio (ν) and porosity (P) of two commercial glass-ceramics, Empress (E1) and Empress 2 (E2), as a function of the hot-pressing temperature. Ten disks were hot-pressed at 1065, 1070, 1075 and 1080 °C for E1; and at 910, 915, 920 and 925 °C for E2. The porosity was measured by an image analyzer software and s f was determined using the piston-on-three-balls method. K Ic and HV were determined by an indentation method. Elastic constants were determined by the pulse-echo method. For E1 samples treated at different temperatures, there were no statistical differences among the values of all evaluated properties. For E2 samples treated at different temperatures, there were no statistical differences among the values of σf, E, and ν, however HV and K Ic were significantly higher for 910 and 915 °C, respectively. Regarding P, the mean value obtained for E2 for 925 °C was significantly higher compared to other temperatures.