489 research outputs found

    Genomic and toxigenic heterogeneity of bacillus cereus sensu lato Isolated from ready-to-eat foods and powdered milk in day care centers in Colombia

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    Bacillus cereus sensu lato (s.l.) is a group of bacteria commonly found in diverse environments, including foods, with potential to cause emesis and diarrhea. In Colombia, it is one of the main foodborne pathogens. The aim of this study was to determine the genomic and toxigenic heterogeneity of B. cereus s.l. isolated from ready-to-eat foods and powdered milk collected in day care centers of Medellin, Colombia. Of 112 B. cereus s.l. isolates obtained, 94% were beta-hemolytic. Toxigenic heterogeneity was established by the presence of nheABC, hblCDAB, cytK2, entFM, and cesB toxigenic genes. The nheABC operon and entFM gene were most frequently detected in the isolates, whereas the cesB gene was not found. According to the toxin genes content, nine toxigenic profiles were identified. A 44% of isolates had profiles with all genes for nonhemolytic enterotoxin, hemolysin BL, and enterotoxin FM production (profiles II and IV). Pulsed-field gel electrophoresis analysis indicated a high genomic heterogeneity among the B. cereus s.l., with 68 isolates grouping into 16 clusters and 33 placed separately in the dendrogram. This study provides useful information on the safety of ready-to-eat foods and powdered milk in day care centers where children, a susceptible population, are exposed and it should incentive for more studies to understand the distribution of different toxin-encoding genes among B. cereus s.l. isolates, enabling detailed risk assessment

    Kinetic Modeling of the UV/H2O2 Process: Determining the Effective Hydroxyl Radical Concentration

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    A kinetic model for pollutant degradation by the UV/H2O2 system was developed. The model includes the background matrix effect, the reaction intermediate action, and the pH change during time. It was validated for water containing phenol and three different ways of calculating HO° level time-evolution were assumed (non-pseudo-steady, pseudo-steady and simplified pseudo-steady state; denoted as kinetic models A, B and C, respectively). It was found that the kind of assumption considered was not significant for phenol degradation. On the other hand, taking into account the high levels of HO2° formed in the reaction solution compared to HO° concentration (~10–7 M >>>> ~10–14 M), HO2° action in transforming phenol was considered. For this purpose, phenol-HO2° reaction rate constant was calculated and estimated to be 1.6x103 M-1 s-1, resulting in the range of data reported from literature. It was observed that, although including HO2° action allowed slightly improving the kinetic model degree of fit, HO° developed the major role in phenol conversion, due to their high oxidation potential. In this sense, an effective level of HO° can be determined in order to be maintained throughout the UV/H2O2 system reaction time for achieving an efficient pollutant degradation

    Geostatistical modelling of a coal seam for resource risk assessment

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    The evaluation of a coal seam for profitable extraction requires the estimation of its thickness and quality characteristics together with the spatial variability of these variables. In many cases the only data available for the estimation are from a limited number of exploration and feasibility drill holes. Spatial variability can be quantified by geostatistical modelling, which provides the basis for estimation (kriging). In cases where the spatial variability of the seam thickness and quality characteristics has a significant impact on how the coal is extracted and stored, geostatistical simulation may be preferable to geostatistical kriging methods. The aim of this paper is to present an improved approach to resource risk assessment by propagating the uncertainty in semi-variogram model parameters into the spatial variability of coal variables. We show that a more realistic assessment of risk is obtained when the uncertainty of semi-variogram model parameters is taken into account. The methodology is illustrated with a coal seam from North-western Spain. © 2012 Elsevier B.V.E. Pardo-Igúzquiza, P.A. Dowd, J.M. Baltuille, M. Chica-Olm

    Correction of Errors During The Manufacture by Computer Numerical Control (CNC) of Blades for an Axial Hydrokinetic Turbine

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    The design and manufacture of new systems for providing electric power to non-interconnected areas is one of the challenges for engineering. There are several alternatives, including water or wind-power generation systems, where hydrokinetic turbines are highlighted. This work establishes the methodology, identification and correction of errors generated during the manufacture by machining, using CAD/CAPP/CAM techniques, for an axial hydrokinetic turbine. During the manufacturing process, the generation of an error on the edges of the blades was identified, which was attributed to problems in the design of the model since the degrees of freedom of the manufacturing system used were not considered. For the manufacture of complex surfaces in the design of models, the most extreme points of the surfaces in contact must match the tangent edges to ensure that the tools of machining can reach them with the trajectories generated from the CAM

    Sensitive spectrophotometric determination of hydrogen peroxide in aqueous samples from advanced oxidation processes: Evaluation of possible interferences

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    Hydrogen peroxide (H2O2) determination in real watersamples was carried out in a simple and sensitiveway. The resulting optimal operating conditions froma 23 full factorial experimental design were 450 nm, 50mm and 6x10-3 M for the absorption wavelength, thequartz cell path length and the final concentration ofthe ammonium monovanadate solution, respectively;allowing the quantification of H2O2 up to 2.94x10-3mM. The proposed analytical method was validatedand the effect of the background matrix was investigated,obtaining a selective method. Additionally, thedeveloped analytical method was applied for studyingthe evolution of H2O2 in the decontamination of watercontaining 6.73x10-5 mM of anthracene and 1.19x10-5mM of benzo[a]pyrene using the UV/H2O2 system. Itwas found that the optimal H2O2 level enabling about45% of mineralisation and a removal of the targetpolycyclic aromatic hydrocarbons higher than 99%was 2.94x10-1 mM, remaining approximately 1.47x10-1 mM of H2O2 after 90 min of treatment

    DIALOGIC LITERARY GATHERINGS IN PRIMARY EDUCATION. A CASE STUDY

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    In most current schools, an educational system focused on the vertical transmission of knowledge as a teaching model where teachers occupy the dominant position in the teacherstudent relationship predominates. In particular, reading is traditionally considered as a skill to develop from an individual, mechanical and ritualistic approach. From this perspective, the educational institution has serious problems to carry out its mission that is to educate its students to become critical, responsible and educated future citizens of democratic societies. Due to the desire of knowing about educational proposals with a dialogical learning approach that helps to achieve such objectives, this research studies the Dialogic Literary Gatherings (DLG) that take place in a Primary Education classroom of a public school in Málaga, where reading itself is an activity that contributes to this objective. The methodology used has been the case study, using participant observation and semi-structured interviews as the main information gathering techniques. The results from a qualitative analysis show how and why DLG are carried out in a specific classroom and what the experience, impressions and opinions of students and teachers involved in them are. This allows us to get a better understanding of this practice within a real educational context

    Las Tertulias Literarias Dialógicas en Educación Primaria. Un estudio de caso.

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    En la mayoría de las escuelas actuales predomina un sistema educativo centrado en la transmisión vertical de saberes como modelo de enseñanza donde el profesorado ocupa la posición de dominancia en la relación docente-discente. En especial, la lectura es tradicionalmente considerada como una habilidad a desarrollar desde un planteamiento individual, mecánico y ritualista. Desde esta óptica, la institución educativa presenta serias dificultades en su misión por hacer del alumnado futuros ciudadanos/as críticos, responsables y preparados/as para convivir en sociedades democráticas. Partiendo del interés por conocer propuestas educativas basadas en un aprendizaje dialógico que ayuden a alcanzar tales objetivos, la presente investigación se ha orientado al estudio de las Tertulias Literarias Dialógicas (TLD) dentro de un aula de Educación Primaria de una escuela pública de Málaga como actuación desde la cual la propia lectura contribuye a dicho fin. La metodología empleada ha sido el estudio de caso, utilizando como principales técnicas de recogida de información la observación participante y las entrevistas semiestructuradas. Desde el análisis cualitativo de los datos, los resultados ilustran cómo y por qué las TLD se llevan a cabo en dicha aula y cuál es la experiencia, impresiones y opiniones de los niños, niñas y el docente participante en ellas, lo que permite alcanzar una mayor comprensión de esta práctica dentro de un contexto educativo real

    Availability and quality of publicly available health workforce data sources in Australia: a scoping review protocol.

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    IntroductionThe health workforce is an integral component of the healthcare system. Comprehensive, high-quality data on the health workforce are essential to identifying gaps in health service provision, as well as informing future health workforce and health services planning, and health policy. While many data sources are used in Australia for these purposes, the quality of the data sources with respect to relevance, accessibility and accuracy is not clear.Methods and analysisThis scoping review aims to identify and appraise publicly available data sources describing the Australian health workforce. The review will include any data source (eg, registry, administrative database and survey) or document reporting a data source (eg, journal article, report) on the Australian health workforce, which is publicly available and describes the characteristics of the workforce. The search will be conducted in 10 bibliographic databases and the grey literature using an iterative process. Screening of titles and abstracts will be undertaken by two investigators, independently, using Covidence software. Any disagreement between investigators will be resolved by a third investigator. Documents/data sources identified as potentially eligible will be retrieved in full text and reviewed following the same process. Data will be extracted using a customised data extraction tool. A customised appraisal tool will be used to assess the relevance, accessibility and accuracy of included data sources.Ethics and disseminationThe scoping review is a secondary analysis of existing, publicly available data sources and does not require ethics approval. The findings of this scoping review will further our understanding of the quality and availability of data sources used for health workforce and health services planning in Australia. The results will be submitted for publication in peer-reviewed journals and presented at conferences targeted at health workforce and public health topics

    Propuesta de alternativas para la gestión del suelo de equipamientos educativos, en la localidad de Bosa, Distrito Capital

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    Propuesta de alternativas que gestionen la consecución del suelo para proyectos urbanísticos y arquitectónicos del nuevo equipamiento educativo en la localidad de Bosa del Distrito Capital.La construcción de nuevos colegios públicos en Bogotá ha sido una preocupación de todas las administraciones. El aumento de la población impone retos como la reducción del déficit de cupos en algunas zonas y acercar las instituciones para evitar la deserción. Todo bajo una nueva necesidad: estandarizar la jornada única. Pasar más tiempo en la escuela trae significativos beneficios de orden social: disminuye el embarazo adolescente y permite que los niños permanezcan más tiempo en un espacio sano y seguro que los protege de riesgos como la criminalidad, el consumo de sustancias psicoactivas y la deserción escolar. También, padres y madres pueden obtener y conservar trabajos estables, con la tranquilidad de que sus hijos se encuentran seguros; esto contribuye a un mejoramiento en el ingreso y la calidad de vida de las familias. Según la última entrega del estudio “Bogotá cómo vamos”, la deserción escolar en la ciudad alcanza el 3 %. Y una de las razones por las que los menores dejan sus estudios es porque la institución queda lejos de su casa

    Seroprevalence of Neospora caninum infection in cattle from Pereira, Colombia

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    There are over 25.6 million cattle heads in Colombia being the fourth-highest herd in Latin America. This study aimed to describe the seroprevalence of Neospora caninum in cattle from 25 rural farms at Pereira municipality, Risaralda Department, which has a total bovine population of 43,508 animals. A cross-sectional observational study was performed in beef and dairy herds during 2017–2018. A total of 325 animals in 25 herds, with 13 animals per herd, were sampled. A commercial competitive ELISA (cELISA) kit was used to detect N. caninum antibodies. Associated risk factors were analyzed in two different levels: individual animals and herds. For all the independent variables, chi-square (χ2) and Fisher tests were used to assess associations and significance. The overall estimated seropositivity was 20.6% (95%CI 16.2%–25.0%). The seroprevalence by herds was 92.0% ranging from 0.0% to 46.2%. Noteworthy, beef herds had significantly (p = 0.0107) higher seropositivity (50% of them above 35% of seropositivity) compared with those for milk purposes (4.8%) (OR = 20.0; 95%CI 1.2–331.0). Other risk factors were not significantly (p ≥ 0.05) associated with N. caninum seropositivity. Bovine neosporosis may be associated with abortions in both beef and dairy Colombian farms. More studies about the epidemiology, associated factors and consequences, as well as on tools for better diagnosis of bovine abortion, including histopathology and other ancillary tests, should be performed.Fil: Idarraga Bedoya, Samuel E.. Fundación Universitaria Autónoma de las Américas. Facultad de Medicina Veterinaria y Zootecnia; ColombiaFil: Álvarez Chica, Jaime. Fundación Universitaria Autónoma de las Américas. Facultad de Medicina Veterinaria y Zootecnia; ColombiaFil: Bonilla Aldana, D. Katterine. Universidad Tecnológica de Pereira; Colombia. Fundación Universitaria Autónoma de las Américas; ColombiaFil: Moore, Dadin Prando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Rodríguez Morales, Alfonso J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentina. Universidad Tecnológica de Pereira; Colombia. Fundación Universitaria Autónoma de las Américas; Colombi
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