923 resultados para Agrarian colonization
Resumo:
El objetivo de este trabajo es mostrar las posibilidades que ofrece la documentación conservada en el Archivo Histórico del Agua para aproximarse a la cuestión de la creciente implicación del Estado mexicano en el proceso de modernización agraria, a través de la política de fomento a la irrigación, durante la primera parte del siglo XX. Para alcanzar esta meta partimos de la caracterización del modelo agroexportador implementado en México entre 1877 y 1930. Después sintetizamos la evolución del sector agropecuario en el estado de Sinaloa durante ese mismo periodo. Seguidamente, se enfatizan las expectativas iniciales que tuvo la oligarquía sobre la gran irrigación en Sinaloa a partir del estudio, fundamentalmente macroeconómico, de las tres empresas que suscribieron un contrato de subvención con el gobierno federal a fines del Porfiriato. Y, por último, a partir del seguimiento de estos mismos casos, se hacen claros los motivos que nos permiten entender la progresiva pérdida de legitimidad, tras el período revolucionario de 1910, de ese modelo modernizador del agro "desde arriba" con apoyo público hasta su quiebra final.
Resumo:
A pesar de los excelentes avances historiográficos sobre la expansión agrícola santafesina decimonónica, faltan aún datos clave sobre este fenómeno, entre ellos, el comportamiento de los precios de la tierra por lo menos en el mediano y largo plazo. El artículo buscará analizar la emergencia y la evolución del mercado inmobiliario rural en la provincia y, a la vez, presentar series de precios de la tierra entre 1860 y 1895, realizadas a partir de información provista por protocolos notariales. Buscamos así que dicha evidencia no sólo pueda ser de utilidad para investigaciones paralelas, sino que también aporte nuevas hipótesis al conocimiento sobre la formación de los mercados inmobiliarios en la región pampeana
Resumo:
El objetivo de este trabajo es mostrar las posibilidades que ofrece la documentación conservada en el Archivo Histórico del Agua para aproximarse a la cuestión de la creciente implicación del Estado mexicano en el proceso de modernización agraria, a través de la política de fomento a la irrigación, durante la primera parte del siglo XX. Para alcanzar esta meta partimos de la caracterización del modelo agroexportador implementado en México entre 1877 y 1930. Después sintetizamos la evolución del sector agropecuario en el estado de Sinaloa durante ese mismo periodo. Seguidamente, se enfatizan las expectativas iniciales que tuvo la oligarquía sobre la gran irrigación en Sinaloa a partir del estudio, fundamentalmente macroeconómico, de las tres empresas que suscribieron un contrato de subvención con el gobierno federal a fines del Porfiriato. Y, por último, a partir del seguimiento de estos mismos casos, se hacen claros los motivos que nos permiten entender la progresiva pérdida de legitimidad, tras el período revolucionario de 1910, de ese modelo modernizador del agro "desde arriba" con apoyo público hasta su quiebra final.
Resumo:
A pesar de los excelentes avances historiográficos sobre la expansión agrícola santafesina decimonónica, faltan aún datos clave sobre este fenómeno, entre ellos, el comportamiento de los precios de la tierra por lo menos en el mediano y largo plazo. El artículo buscará analizar la emergencia y la evolución del mercado inmobiliario rural en la provincia y, a la vez, presentar series de precios de la tierra entre 1860 y 1895, realizadas a partir de información provista por protocolos notariales. Buscamos así que dicha evidencia no sólo pueda ser de utilidad para investigaciones paralelas, sino que también aporte nuevas hipótesis al conocimiento sobre la formación de los mercados inmobiliarios en la región pampeana
Resumo:
A pesar de los excelentes avances historiográficos sobre la expansión agrícola santafesina decimonónica, faltan aún datos clave sobre este fenómeno, entre ellos, el comportamiento de los precios de la tierra por lo menos en el mediano y largo plazo. El artículo buscará analizar la emergencia y la evolución del mercado inmobiliario rural en la provincia y, a la vez, presentar series de precios de la tierra entre 1860 y 1895, realizadas a partir de información provista por protocolos notariales. Buscamos así que dicha evidencia no sólo pueda ser de utilidad para investigaciones paralelas, sino que también aporte nuevas hipótesis al conocimiento sobre la formación de los mercados inmobiliarios en la región pampeana
Resumo:
El objetivo de este trabajo es mostrar las posibilidades que ofrece la documentación conservada en el Archivo Histórico del Agua para aproximarse a la cuestión de la creciente implicación del Estado mexicano en el proceso de modernización agraria, a través de la política de fomento a la irrigación, durante la primera parte del siglo XX. Para alcanzar esta meta partimos de la caracterización del modelo agroexportador implementado en México entre 1877 y 1930. Después sintetizamos la evolución del sector agropecuario en el estado de Sinaloa durante ese mismo periodo. Seguidamente, se enfatizan las expectativas iniciales que tuvo la oligarquía sobre la gran irrigación en Sinaloa a partir del estudio, fundamentalmente macroeconómico, de las tres empresas que suscribieron un contrato de subvención con el gobierno federal a fines del Porfiriato. Y, por último, a partir del seguimiento de estos mismos casos, se hacen claros los motivos que nos permiten entender la progresiva pérdida de legitimidad, tras el período revolucionario de 1910, de ese modelo modernizador del agro "desde arriba" con apoyo público hasta su quiebra final.
Resumo:
Internal colonization in Switzerland is often seen in connection with the battle for cultivation in the Second World War, but the history of internal colonization in Switzerland is more complex. The food crisis in the First World War formed the horizon of experience for various actors from industry, consumer protection, the urban population and agriculture to start considering practical strategies for managing agricultural production. In this way, traditional spaces, such as rural and urban areas and economic roles, such as food producer, consumer and trader, overlapped and were newly conceived to some extent: people started thinking about utopias and how a modern society could be designed to be harmonious and resistant to crisis. The aim of this article is to trace some of the key points in this process for the interwar years in neutral Switzerland. In the process, the focus must be on the context of people’s mentalities in the past, although the relationships between the actors of internal colonization and the state also need to be considered. Internal colonization in Switzerland in the twentieth century can be understood as an open process. In principle, the project was driven by private actors, but in times of crisis, the project was claimed by the state as a possible tool for social and economic intervention. In addition, as a result of the planned dissolution of urban and rural spaces, it will be shown that modern societies in the interwar period were on an existential search to overcome the problems of the modern age. Internal colonization can therefore be seen as an attempt to find a third way between a world characterized by an agrarian society and a modern industrial nation.
Resumo:
Numerous challenges remain in the successful clinical translation of cell-based therapies for musculoskeletal tissue repair, including the identification of an appropriate cell source and a viable cell delivery system. The aim of this study was to investigate the attachment, colonization, and osteogenic differentiation of two stem cell types, human mesenchymal stem cells (hMSCs) and human amniotic fluid stem (hAFS) cells, on electrospun nanofiber meshes. We demonstrate that nanofiber meshes are able to support these cell functions robustly, with both cell types demonstrating strong osteogenic potential. Differences in the kinetics of osteogenic differentiation were observed between hMSCs and hAFS cells, with the hAFS cells displaying a delayed alkaline phosphatase peak, but elevated mineral deposition, compared to hMSCs. We also compared the cell behavior on nanofiber meshes to that on tissue culture plastic, and observed that there is delayed initial attachment and proliferation on meshes, but enhanced mineralization at a later time point. Finally, cell-seeded nanofiber meshes were found to be effective in colonizing three-dimensional scaffolds in an in vitro system. This study provides support for the use of the nanofiber mesh as a model surface for cell culture in vitro, and a cell delivery vehicle for the repair of bone defects in vivo.
Resumo:
Objective: To assess the efficacy of maternal betamethasone for improving preterm lung function, in the presence of inflammation induced by amniotic fluid ureaplasma colonization. ----- ----- Study design: Ewes bearing single fetuses were randomized to receive an intra-amniotic injection of Ureaplasma parvum (serovar 6; 2×107 colony forming units) or vehicle at 86±2 days of pregnancy (mean±SD: term is 150d), followed by maternal intramuscular betamethasone (0.5mg/kg) or saline, either 2 or 7 days before delivery of lambs at 123±1d. ----- ----- Results: Amniotic fluid IL-8 was elevated by ureaplasmas (p=0.049) but unaffected by betamethasone. Lung inflammation induced by ureaplasmas was not affected by betamethasone. Lung compliance was increased by ureaplasma colonization (p=0.009) and betamethasone (p=0.042), and effects were additive. Lung surfactant was increased by ureaplasma colonization (p<0.001) and betamethasone 7 days (p=0.001), but not 2 days, before delivery. ----- ----- Conclusion: Inflammation improves preterm lung function due to increases in surfactant. Antenatal corticosteroids further augment lung function, through an apparently independent mechanism.
Resumo:
Increased or fluctuating resources may facilitate opportunities for invasive exotic plants to dominate. This hypothesis does not, however, explain how invasive species succeed in regions characterized by low resource conditions or how these species persist in the lulls between high resource periods. We compare the growth of three co-occurring C4 perennial bunchgrasses under low resource conditions: an exotic grass, Eragrostis curvula (African lovegrass) and two native grasses, Themeda triandra and Eragrostis sororia. We grew each species over 12 weeks under low nutrients and three low water regimes differentiated by timing: continuous, pulsed, and mixed treatments (switched from continuous to pulsed and back to continuous). Over time, we measured germination rates, time to germination (first and second generations), height, root biomass, vegetative biomass, and reproductive biomass. Contrary to our expectations that the pulsed watering regime would favor the invader, water-supply treatments had little significant effect on plant growth. We did find inherent advantages in a suite of early colonization traits that likely favor African lovegrass over the natives including faster germination speed, earlier flowering times, faster growth rates and from 2 weeks onward it was taller. African lovegrass also showed similar growth allocation strategies to the native grasses in terms of biomass levels belowground, but produced more vegetative biomass than kangaroo grass. Overall our results suggest that even under low resource conditions invasive plant species like African lovegrass can grow similarly to native grasses, and for some key colonization traits, like germination rate, perform better than natives.
Resumo:
Background/Aims: The aim of this study was to investigate the colonization of mutans streptococci (MS) and lactobacilli (LB) in predentate children from the neonatal period to 7 months. Methods: A total of 957 mother-and-child pairs were recruited from birth and followed up at 7 months. The 283 children who did not have erupted teeth at the second visit were included in the study. Oral mucosal swabs were taken, and the presence of MS and LB was determined using a commercial microbiological culture kit. Results: At mean ages of 34 days and 7 months, 9 and 11% of the infants, respectively, showed the presence of MS. In contrast, LB presence increased from 24 to 47% (p < 0.0001). MS presence in the neonatal period was associated with maternal MS counts of >105 CFU/ml (p = 0.05), while LB presence was associated with natural birth (p = 0.03) and maternal LB presence (p = 0.02). At 7 months, MS presence was associated with maternal MS counts (p = 0.02) and LB counts of >105 CFU/ml (p = 0.007). Additional predictors of MS presence at 7 months were a child’s MS counts of >105 CFU/ml at the neonatal visit (p = 0.019) and nighttime bottle feeding (p = 0.024). LB presence at 7 months was associated with maternal LB (p < 0.001) and MS presence (p = 0.02). Conclusions: MS and LB can be detected by culture in the oral cavity as early as 34 days after birth. Their infection rates increase to 11 and 47%, respectively, by the time the children reach the end of the predentate stage of oral development.
Resumo:
The obligate endosymbiont Wolbachia pipientis is found in a wide range of invertebrates where they are best known for manipulating host reproduction. Recent studies have shown that Wolbachia also can modulate the lifespan of host insects and interfere with the development of human pathogens in mosquito vectors. Despite considerable study, very little is known about the molecular interactions between Wolbachia and its hosts that might mediate these effects. Using microarrays, we show that the microRNA (miRNA) profile of the mosquito, Aedes aegypti, is significantly altered by the wMelPop-CLA strain of W. pipientis. We found that a host miRNA (aae-miR-2940) is induced after Wolbachia infection in both mosquitoes and cell lines. One target of aae-miR-2940 is the Ae. aegypti metalloprotease gene. Interestingly, expression of the target gene was induced after Wolbachia infection, ectopic expression of the miRNA independent of Wolbachia, or transfection of an artificial mimic of the miRNA into mosquito cells. We also confirmed the interaction of aae-miR-2940 with the target sequences using GFP as a reporter gene. Silencing of the metalloprotease gene in both Wolbachia-infected cells and adult mosquitoes led to a significant reduction in Wolbachia density, as did inhibition of the miRNA in cells. These results indicate that manipulation of the mosquito metalloprotease gene via aae-miR-2940 is crucial for efficient maintenance of the endosymbiont. This report shows how Wolbachia alters the host miRNA profile and provides insight into the mechanisms of host manipulation used by this widespread endosymbiont.
Resumo:
Ureaplasma species are the microorganisms most frequently associated with adverse pregnancy outcomes. The multiple banded antigen (MBA), a surface-exposed lipoprotein, is a key virulence factor of ureaplasmas. The MBA demonstrates size variation, which we have shown previously to be correlated with the severity of chorioamnion inflammation. We aimed to investigate U. parvum serovar 3 pathogenesis in vivo, using a sheep model, by investigating: MBA variation after long term (chronic) and short term (acute) durations of in utero ureaplasma infections, and the severity of chorioamnionitis and inflammation in other fetal tissues. Inocula of 2x107 colony-forming-units (CFU) of U. parvum serovar 3 (Up) or media controls (C) were injected intra-amniotically into pregnant ewes at one of three time points: day 55 (69d Up, n=8; C69, n=4); day 117 (7d Up, n=8; C7, n=2); and day 121 (3d Up, n=8; C3, n=2) of gestation (term=145-150d). At day 124, preterm fetuses were delivered surgically. Samples of chorioamnion, fetal lung, and umbilical cord were: (i) snap frozen for subsequent ureaplasma culture, and (ii) fixed, embedded, sectioned and stained by haematoxylin and eosin stain for histological analysis. Selected fetal lung clinical ureaplasma isolates were cloned and filtered to obtain cultures from a single CFU. Passage 1 and clone 2 ureaplasma cultures were tested by western blot to demonstrate MBA variation. In acute durations of ureaplasma infection no MBA variants (3d Up) or very few MBA variants (7d Up) were present when compared to the original inoculum. However, numerous MBA size variants were generated in vivo (alike within contiguous tissues, amniotic fluid and fetal lung, but different variants were present within chorioamnion), during chronic, 69d exposure to ureaplasma infection. For the first time we have shown that the degree of ureaplasma MBA variation in vivo increased with the duration of gestation.