Educación cimarrona

La presente obra consta de tres partes bien definidas: la primera expone el resultado de los talleres y el trabajo de las coordinadoras de los Centros de Educación Cimarrona de los siguientes barrios de Sucumbíos: El Cisne, Amazonas, San Valentín y la parroquia Pacayacu, y recupera historias de viada de hombres y mujeres así como la tradición oral presente en su memoria colectiva y recuperada por el grupo de trabajo. La segunda parte consta de las reflexiones teóricas sobre el cimarronaje y los fundamentos conceptuales que inspiran los Centros de Educación Cimarrona. La tercera y última sección ofrece, en primer lugar, el relato reflexivo de los talleres de grafoplástica identitaria y, luego, una guía para niños investigadores al servicio de la revitalización de la cultura, las identidades y las memorias vivas de los pueblos cimarrone

Pervasive Influence of Hepatitis C Virus on the Phenotype of Antiviral CD8+ T Cells

Recent studies using MHC class I tetramers have shown that CD8(+) T cell responses against different persistent viruses vary considerably in magnitude and phenotype. At one extreme, hepatitis C virus (HCV)-specific CD8(+) T cell responses in blood are generally weak and have a phenotype that is perforin low and CCR7 high (early memory). At the other, specific responses to CMV are strong, perforin high, and CCR7 low (mature or effector memory). To examine the potential mechanisms behind this diversity, we compared CMV-specific responses in HCV-infected and healthy individuals. We find a striking difference in the phenotype of CMV-specific CD8(+) T cells between these groups. In the HCV-infected cohort, CMV-specific CD8(+) T cells lost markers associated with maturity; they had increased expression of CCR7 and reduced expression of Fas and perforin. They nevertheless responded to Ag in vitro in a manner similar to controls, with strong proliferation and appropriate acquisition of effector memory markers. The reduction in mature CD8 T cells in HCV-infected individuals may arise through either impairment or regulation of T cell stimulation, or through the early loss of mature T cells. Whatever the mechanism, HCV has a pervasive influence on the circulating CD8(+) T cell population, a novel feature that may be a hallmark of this infection

The production of cyclopiazonic acid by Penicillium commune and cyclopiazonic acid and aflatoxins by Aspergillus flavus as affected by water activity and temperature on maize grains

The combined effects of water activity (aw) and temperature on mycotoxin production by Penicilium commune (cyclopiazonic acid - CPA) and Aspergillus flavus (CPA and aflatoxins - AF) were studied on maize over a 14-day period using a statistical experimental design. Analysis of variance showed a highly significant interaction (P 0.001) between these factors and mycotoxin production. The minimum aw/temperature for CPA production (2264 ng g-1 P. commune, 709 ng g-1 A. flavus) was 0.90 aw/30 °C while greatest production (7678 ng g-1 P. commune, 1876 ng g-1 A. flavus) was produced at 0.98 aw/20 °C. Least AF (411 ng g-1) was produced at 0.90 aw/20 °C and most (3096 ng g-1) at 0.98 aw/30 °C

Biochemical changes associated with electron beam irradiation of rice and links to kernel discoloration during storage

Background and objectives Rice kernel discoloration during storage results in significant economic losses to rice growers and processors. This study aimed to elucidate the extent of chemical changes and microbial involvement on discoloration of rice kernels during storage. To segregate and/or diminish the effects of microbes, one lot of hybrid long-grain rice (XL753) samples was irradiated with nonthermal electron beam (EB) dose of 14 kGy. The irradiated and nonirradiated control samples of rice at a moisture content (MC) of 21% on a wet basis were stored at three temperatures (20, 30, and 40 degrees C) for 8 weeks. Samples were taken every 2 weeks for microbial and chemical analyses. Findings A negative relationship was noted between discoloration and microbial load. The trend of increasing discoloration and chemical properties such as free sugars, free fatty acid, and free 5-hydroxymethyl-2-furaldehyde (HMF), especially at higher storage temperatures and durations, suggested that biochemical changes were major drivers of the observed rice discoloration. The higher HMF in highly discolored rice (>= 20%) explained nonenzymatic browning in the rice matrix during storage. Conclusions From this study, it was drawn that the rice kernel discoloration was not directly related to the microbial load; the discoloration was seen in EBI rice even with 99% reduction in microbial load. However, it was clarified that the rice discoloration especially in EBI rice samples was related to the observed chemical changes, which were also storage temperature dependent. Significance and novelty Milled rice discoloration during storage of rough rice is insufficiently understood. There is no information correlating changes in chemical attributes and microbial activity to discoloration of contemporary hybrid rice during storage. Therefore, the results of the current study provide important fundamental information and also suggest storage conditions required to arrest discoloration and maintain quality of contemporary milled hybrid rice