191 research outputs found

    Formación inicial de profesores de educación media de ciencia mediante la teoría de enseñanza y aprendizaje basada en modelos mentales

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    Este estudio describe cómo se aplica la Teoría de los Modelos Mentales en la formación inicial del profesor de Ciencias de enseñanza media en la Facultad de Educación de la Universidad de Concepción. Esta nueva modalidad de formación, se introdujo a partir del año 2004, en las asignaturas de Didáctica III y IV y en el desarrollo de la tesis de pregrado. Los sesenta estudiantes participantes de la experiencia generaron más de treinta planificaciones de unidades sobre diferentes temas científicos, en las que se utiliza la Teoría de los Modelos Mentales, y que han aplicado a alumnos de enseñanza media. Los dos estudios pilotos que midieron la efectividad de estas planificaciones, indican que el uso de esta perspectiva genera auspiciosos resultados en el aprendizaje de los estudiantes de enseñanza media y en la organización del quehacer en el aula del futuro docente

    Granitoides paleozoicos de la Sierra de Narváez, Sistema de Famatina, Argentina: Hibridización de magmas en un margen continental activo

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    The granitoids from the Sierra de Narváez were investigated for their geochemical and petrographical characteristics. They are composed of calc-alkaline granites, granodiorites and tonalites, similar to the other paleozoic granitoids of the Famatina System. These rocks are intrusive in the Las Planchadas (volcanic rocks) and Suri (sedimentary rocks) Formations, which are probably cogenetic with the granitoids within the same magmatic cycle.The study of the granitoids reveals the close relationship between their composition and the abundance of the enclosed magmatic inclusions. The latter represent rocks and granodioritic tonalitic and diorite composition, and have a great number of mineralogical characteristic that suggest the presence of two magmas, mafic and felsic for the origin of such enclaves.The close chemical relationship existing between the inclusions and their host rocks shows that the mafic and felsic components are compositionally modified and that the granitoids are more or less hybridized.Trace elements discrimination diagrams have been used as a tools for fingerprinting the tectonic setting of the Sierra de Narváez granitoids. The geochemistry as well as the geologic relations of the granitoids with the roughly coeval ordovician vulcanism indicate a volcanic arc environment.Las rocas que afloran en el extremo septentrional de la Sierra de Narváez están representadas por una asociación de monzogranitos, granodioritas y tonalitas que definen una serie calcoalcalina, de características similares a las de otros intrusivos del Paleozoico del Sistema de Famatina. Estos granitoides se hallan intruyendo las Formaciones Las Planchadas y Suri, representadas por vulcanitas y metasedimentitas, respectivamente, y corresponderían a un mismo evento magmático del Paleozoico Inferior.Los granitoides estudiados presentan abundantes inclusiones ígneas de composición granodiorítica o tonalítica y diorítica. La estrecha relación que existe en el quimismo de estas rocas, junto a las evidencias petrográficas y geológicas, nos hace pensar que la presencia de estos enclaves se debería a un proceso de interacción de magmas, félsico y máfico, los que habrían sufrido considerables modificaciones composicionales con la hibridación de los granitoides.La utilización de los elementos trazas en diagramas discriminatorios, juntamente con las relaciones geológicas establecidas y las características petrográficas y químicas, nos permite inferir que los granitoides de la Sierra de Narváez corresponderían a un ambiente tectónico de arco volcánico, íntimamente relacionado con el evento efusivo ordovícico

    Serological diagnosis of brucellosis in goats: comparison of techniques

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    Goat production is an important item in the agricultural system of Argentina and brucellosis caused by Brucella melitensis is considered the main cause reproductive problems in this species. Although definitive diagnosis for this disease is made by isolation of the etiologic agent, but in practice the health status of a herd was evaluated by serological techniques indirect testing. To evaluate and compare the performance of different serological tests for diagnosis of brucellosis in goats, serum samples were analyzed. The following tests were performed: buffered plate antigen (BPA), rose bengal (RB RB 3% and 8%), fluorescence polarization (FPA) and the test tube and 2-mercaptoethanol (SAT/2ME). The validity of each test was determined in a relative manner by combination of indirect ELISA (IELISA) and complement fixation (CF). BPA was the most sensitive test, followed by SAT/2ME, 3% RB, FPA and, finally, RB 8%. FPA test, when used in series with BPA, significantly improved overall specificity. Based on these results it was proposed for brucellosis diagnosis in goats, BPA as a screening test, FPA as complementary test, and FC and IELISA as confirmatory tests. SAT/2ME is recommended only when it is not possible to perform other tests, due to the toxic effects of SAT/2ME reagents.Fil: Cisterna, C. Comisión de Investigaciones Científicas (CIC). Buenos Aires, ArgentinaFil: Conde, S. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología. Buenos Aires, ArgentinaFil: Hollender, D. CONICET. ArgentinaFil: Martino, P.E. Comisión de Investigaciones Científicas (CIC). Buenos Aires, ArgentinaFil: Samartino L. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología. Buenos Aires, ArgentinaLa producción caprina representa un rubro importante dentro del sistema agropecuario de la República Argentina y la brucelosis causada por Brucella melitensis es considerada el motivo principal de los problemas reproductivos en esta especie. El diagnóstico de certeza se realiza aislando el agente etiológico, aunque en la práctica se evalúa el estado sanitario de un hato mediante pruebas serológicas. El objetivo de este trabajo fue evaluar y comparar el desempeño de las distintas pruebas serológicas tamíz y complementarias para el diagnóstico de la brucelosis caprina. Para ello, se analizaron muestras de suero de animales sin vacunación, realizando antígeno buferado en placa (BPA), rosa de bengala (RB 3 % y RB 8 %), polarización fluorescente (FPA) y pruebas de tubo y 2 mercaptoetanol (SAT/2ME). La validez de cada prueba se determinó por combinación de ELISA Indirecto (IELISA) y Fijación de Complemento (FC). BPA resultó ser más sensible, seguido de SAT/2ME, RB 3%, FPA y por último RB 8%. Al realizar FPA en serie con BPA mejoró significativamente la especificidad global. Se propone BPA como prueba tamíz, FPA como complementaria y FC e IELISA como confirmatorias. Se recomienda SAT/2ME sólo en los casos en que no sea posible la realización de las otras pruebas debido a los efectos tóxicos de los reactivos empleados para su realización

    Connexins and Pannexins in Bone and Skeletal Muscle

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    PURPOSE OF REVIEW: To discuss current knowledge on the role of connexins and pannexins in the musculoskeletal system. RECENT FINDINGS: Connexins and pannexins are crucial for the development and maintenance of both bone and skeletal muscle. In bone, the presence of connexin and more recently of pannexin channels in osteoblasts, osteoclasts, and osteocytes has been described and shown to be essential for normal skeletal development and bone adaptation. In skeletal muscles, connexins and pannexins play important roles during development and regeneration through coordinated regulation of metabolic functions via cell-to-cell communication. Further, under pathological conditions, altered expression of these proteins can promote muscle atrophy and degeneration by stimulating inflammasome activity. In this review, we highlight the important roles of connexins and pannexins in the development, maintenance, and regeneration of musculoskeletal tissues, with emphasis on the mechanisms by which these molecules mediate chemical (e.g., ATP and prostaglandin E2) and physical (e.g., mechanical stimulation) stimuli that target the musculoskeletal system and their involvement in the pathophysiological changes in both genetic and acquired diseases

    Short communication: Massive mortality in rabbits by maduramicin poisoning

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    [EN] A spontaneous outbreak of maduramicin intoxication in domestic rabbits (Oryctolagus cuniculus) is reported. It is believed that maduramicin incorporated as a coccidiostat into poultry pellet fed to rabbits was the cause, as up to 2.01 ppm was found in the samples and cardiopulmonary clinical signs in most of the rabbits was the common pattern. Findings here were consistent with the classic indications observed in ionophore toxicosis in different species, but little is known about the toxicity of maduramicin in rabbits.This study was partially supported by grants from CIC (Provincial Scientific Research Council), and SENASA (Argentina).Martino, P.; Parrado, E.; Sanguinetti, R.; Espinoza, C.; Debenedetti, R.; Di Benedetto, N.; Cisterna, C.... (2009). Short communication: Massive mortality in rabbits by maduramicin poisoning. World Rabbit Science. 17(1):45-48. https://doi.org/10.4995/wrs.2009.670454817

    Workplace interventions for cardiovascular diseases: protocol of a systematic review and meta-analysis

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    INTRODUCTION: Cardiovascular diseases (CVDs) are the number one cause of death globally, impacting on public and private sectors. Current traditional interventions to prevent CVDs are mainly provided in healthcare centres and even when they are effective, they are not enough to reduce the rising prevalence; therefore, additional strategies are needed. Evidence suggests that health interventions in the workplace supply numerous benefits improving cardiovascular risk factor profiles in individuals. Hence, the aim of this systematic review and meta-analysis is to collate the evidence from randomised controlled trials, cluster randomised trials and quasi-experimental studies of workplace interventions to determine their effectiveness in terms of improving cardiovascular risk factors and preventing CVDs. METHODS AND ANALYSIS: EMBASE, PsycINFO, PubMed, the Cochrane Central Register of Controlled Trials, LILACS, Scopus, Web of Science, WHO International Clinical Trials Registry Platform, ClinicalTrials.gov and ProQuest Dissertations & Theses Global will be searched to include articles on workplace interventions in adults for CVDs events, cardiometabolic risk factors or behavioural risk factors. The study selection, data extraction, risk of bias and the assessment of the quality of the body of evidence will be conducted by two reviewers working in parallel and disagreements will be resolved by consensus or consultations with a third reviewer. Data synthesis will be done by meta-analysis using random-effects models when possible, otherwise the vote counting method will be applied. Statistical heterogeneity will be assessed by a χ(2) test and I(2) statistics. The quality of the body of evidence for each outcome will be assessed by applying the Grading of Recommendations, Assessment, Development and Evaluation approach. ETHICS AND DISSEMINATION: Ethical approval is not required for this systematic review protocol. The results of the systematic review will be published in a peer-reviewed journal and will be publicly available. PROSPERO REGISTRATION NUMBER: CRD42021276161

    Phylodynamics of vampire bat-transmitted rabies in Argentina

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    Common vampire bat populations distributed from Mexico to Argentina are important rabies reservoir hosts in Latin America. The aim of this work was to analyse the population structure of the rabies virus (RABV) variants associated with vampire bats in the Americas and to study their phylodynamic pattern within Argentina. The phylogenetic analysis based on all available vampire bat-related N gene sequences showed both a geographical and a temporal structure. The two largest groups of RABV variants from Argentina were isolated from northwestern Argentina and from the central western zone of northeastern Argentina, corresponding to livestock areas with different climatic, topographic and biogeographical conditions, which determined their dissemination and evolutionary patterns. In addition, multiple introductions of the infection into Argentina, possibly from Brazil, were detected. The phylodynamic analysis suggests that RABV transmission dynamics is characterized by initial epizootic waves followed by local enzootic cycles with variable persistence. Anthropogenic interventions in the ecosystem should be assessed taking into account not only the environmental impact but also the potential risk of disease spreading through dissemination of current RABV lineages or the emergence of novel ones associated with vampire bats.Fil: Torres, Carolina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lema, C.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud; ArgentinaFil: Gury Dohmen, F.. Instituto de Zoonosis “Dr. Luis Pasteur”; ArgentinaFil: Beltran, F.. Instituto de Zoonosis “Dr. Luis Pasteur”; ArgentinaFil: Novaro, L.. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Russo, S.. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Freire, M. C.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud; ArgentinaFil: Velasco Villa, A.. Centers for Disease Control and Prevention; Estados UnidosFil: Mbayed, Viviana Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cisterna , D. M.. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; Argentin

    Diagnóstico serológico de brucelosis en caprinos: comparación de técnicas = Serological diagnosis of brucellosis in goats: comparison of techniques

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    La producción caprina representa un rubro importante dentro del sistema agropecuario de la República Argentina y la brucelosis causada por Brucella melitensis es considerada el motivo principal de los problemas reproductivos en esta especie. El diagnóstico de certeza se realiza aislando el agente etiológico, aunque en la práctica se evalúa el estado sanitario de un hato mediante pruebas serológicas. El objetivo de este trabajo fue evaluar y comparar el desempeño de las distintas pruebas serológicas tamíz y complementarias para el diagnóstico de la brucelosis caprina. Para ello, se analizaron muestras de suero de animales sin vacunación, realizando antígeno buferado en placa (BPA), rosa de bengala (RB 3 % y RB 8 %), polarización fluorescente (FPA) y pruebas de tubo y 2 mercaptoetanol (SAT/2ME). La validez de cada prueba se determinó por combinación de ELISA Indirecto (IELISA) y Fijación de Complemento (FC). BPA resultó ser más sensible, seguido de SAT/2ME, RB 3%, FPA y por último RB 8%. Al realizar FPA en serie con BPA mejoró significativamente la especificidad global. Se propone BPA como prueba tamíz, FPA como complementaria y FC e IELISA como confirmatorias. Se recomienda SAT/2ME sólo en los casos en que no sea posible la realización de las otras pruebas debido a los efectos tóxicos de los reactivos empleados para su realización.Goat production is an important item in the agricultural system of Argentina and brucellosis caused by Brucella melitensis is considered the main cause reproductive problems in this species. Although definitive diagnosis for this disease is made by isolation of the etiologic agent, but in practice the health status of a herd was evaluated by serological techniques indirect testing. To evaluate and compare the performance of different serological tests for diagnosis of brucellosis in goats, serum samples were analyzed. The following tests were performed: buffered plate antigen (BPA), rose bengal (RB RB 3% and 8%), fluorescence polarization (FPA) and the test tube and 2-mercaptoethanol (SAT/2ME). The validity of each test was determined in a relative manner by combination of indirect ELISA (IELISA) and complement fixation (CF). BPA was the most sensitive test, followed by SAT/2ME, 3% RB, FPA and, finally, RB 8%. FPA test, when used in series with BPA, significantly improved overall specificity. Based on these results it was proposed for brucellosis diagnosis in goats, BPA as a screening test, FPA as complementary test, and FC and IELISA as confirmatory tests. SAT/2ME is recommended only when it is not possible to perform other tests, due to the toxic effects of SAT/2ME reagents.Instituto de PatobiologíaFil: Cisterna, C. Comisión de Investigaciones Científicas, Buenos Aires; ArgentinaFil: Conde, S. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiologia; ArgentinaFil: Hollender, Daina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martino, Pablo Eduardo. Universidad Nacional de La Plata. Facultad de Veterinaria. Departamento de Patología y Microbiología; ArgentinaFil: Samartino, Luis Ernesto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiologia; Argentin

    Streptococcus pneumoniae Coinfection Is Correlated with the Severity of H1N1 Pandemic Influenza

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    Initial reports in May 2009 of the novel influenza strain H1N1pdm estimated a case fatality rate (CFR) of 0.6%, similar to that of seasonal influenza. In July 2009, however, Argentina reported 3056 cases with 137 deaths, representing a CFR of 4.5%. Potential explanations for increased CFR included virus reassortment or genetic drift, or infection of a more vulnerable population. Virus genomic sequencing of 26 Argentinian samples representing both severe and mild disease indicated no evidence of reassortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence. Furthermore, no evidence was found for increased frequency of risk factors for H1N1pdm disease.We examined nasopharyngeal swab samples (NPS) from 199 cases of H1N1pdm infection from Argentina with MassTag PCR, testing for 33 additional microbial agents. The study population consisted of 199 H1N1pdm-infected subjects sampled between 23 June and 4 July 2009. Thirty-nine had severe disease defined as death (n = 20) or hospitalization (n = 19); 160 had mild disease. At least one additional agent of potential pathogenic importance was identified in 152 samples (76%), including Streptococcus pneumoniae (n = 62); Haemophilus influenzae (n = 104); human respiratory syncytial virus A (n = 11) and B (n = 1); human rhinovirus A (n = 1) and B (n = 4); human coronaviruses 229E (n = 1) and OC43 (n = 2); Klebsiella pneumoniae (n = 2); Acinetobacter baumannii (n = 2); Serratia marcescens (n = 1); and Staphylococcus aureus (n = 35) and methicillin-resistant S. aureus (MRSA, n = 6). The presence of S. pneumoniae was strongly correlated with severe disease. S. pneumoniae was present in 56.4% of severe cases versus 25% of mild cases; more than one-third of H1N1pdm NPS with S. pneumoniae were from subjects with severe disease (22 of 62 S. pneumoniae-positive NPS, p = 0.0004). In subjects 6 to 55 years of age, the adjusted odds ratio (OR) of severe disease in the presence of S. pneumoniae was 125.5 (95% confidence interval [CI], 16.95, 928.72; p<0.0001).The association of S. pneumoniae with morbidity and mortality is established in the current and previous influenza pandemics. However, this study is the first to demonstrate the prognostic significance of non-invasive antemortem diagnosis of S. pneumoniae infection and may provide insights into clinical management
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