167 research outputs found

    Laboratory activity to effectively teach introductory geomicrobiology concepts to non-geology majors

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    We have designed a three-week experiment that can complement any microbiology course, to teach main geomicrobiology concepts for non-geology majors. One of the most difficult concepts for non-geology majors to comprehend is how bacteria serve as a platform for different mineralization reactions. In our three-week laboratory practice, students learn the main principles and conditions required for an induced bacterial mineralization. Upon completion of the laboratory experience, students will: 1) learn how microbial-induced mineralization (such as calcium carbonate formation) is affected by differential media and growth conditions; 2) understand how bacterial physiology affects any induced in situ or in vitro mineralization; 3) comprehend how growing conditions and bacterial physiologies interrelate, resulting in differential crystal formation. The teaching-learning process was assessed using a pre-/posttest with an increase from 26% to 76% in the number of positive answers from the students. We also measured the students' proficiency while conducting specific technical tasks, revealing no major difficulties while conducting the experiments. A final questionnaire was provided with satisfactory evaluations from the students regarding the organization and content of the practices. 84-86% of the students agreed that the exercises improved their knowledge in geomicrobiology and would like to attend similar laboratories in the future. Such response is the best indicator that the laboratory practice can be implemented in any undergraduate/graduate microbiology course to effectively teach basic geomicrobiology concepts to non-geology majors

    Puerto Rico School Administrators’ Authentic Leadership and Turnover Intent Moderated by Supervisor Support

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    The turnover rates of Puerto Rican high school teachers continue to increase and have an adverse effect not only on the quality of education but also on the budget of Puerto Rico’s Department of Education (PRDE). By examining the factors of perceived supervisor support and authentic leadership influencing teachers’ turnover intentions, steps can be taken to reduce the turnover rates. The purpose of this study was to examine the relationship between school administrators’ authenticity and the turnover intentions of a sample of high school teachers employed by the PRDE. The framework was based on social exchange theory, authentic leadership theory, and the concept of turnover. The Authentic Leadership Questionnaire, the Turnover Intention Scale, the Perceived Supervisor Support Scale, and a demographic information sheet were used to collect data from the 294 high school teachers employed by the PRDE at the time of the study. By using moderated multiple regression, perceived supervisor support, years of teaching experience, and gender were used as factors to analyze the relationship between school administrators perceived authentic leadership and teachers’ turnover intentions. The results showed a significant relationship between school administrators’ authenticity and teachers’ turnover intentions. Perceived supervisor support, years of teaching experience, and gender also significantly moderated the relationship between school administrators’ authenticity and teachers’ turnover intentions. The results may be used by the PRDE and any organizational scenario with similar conditions and culture to make decisions and implement policies and strategies to decrease teachers’ turnover rates leading to positive social change

    Building Safe Community Spaces for Immigrant Families, one Library at a Time

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    In today’s political climate, supporting the needs of young children from Latinx immigrant families has become increasingly difficult at the community, institutional, state, and federal levels. This essay is about a group of Latinx families who participated in an innovative early literacy program at a county public library branch in the migration setting of the U.S. Southeast known as the New Latino Diaspora (Hamann, Wortham, Murillo, 2015). We describe the program and its role in building a safe and welcoming environment for Latinx students and their families. We include the voices of the librarian and parents who had never before participated in a family literacy series for Spanish-speaking immigrants. We conclude with a discussion about factors that foster an inclusive community space for educational experiences

    Laboratory activity to effectively teach introductory geomicrobiology concepts to non-geology majors

    Get PDF
    We have designed a three-week experiment that can complement any microbiology course, to teach main geomicrobiology concepts for non-geology majors. One of the most difficult concepts for non-geology majors to comprehend is how bacteria serve as a platform for different mineralization reactions. In our three-week laboratory practice, students learn the main principles and conditions required for an induced bacterial mineralization. Upon completion of the laboratory experience, students will: 1) learn how microbial-induced mineralization (such as calcium carbonate formation) is affected by differential media and growth conditions; 2) understand how bacterial physiology affects any induced in situ or in vitro mineralization; 3) comprehend how growing conditions and bacterial physiologies interrelate, resulting in differential crystal formation. The teaching-learning process was assessed using a pre-/posttest with an increase from 26% to 76% in the number of positive answers from the students. We also measured the students' proficiency while conducting specific technical tasks, revealing no major difficulties while conducting the experiments. A final questionnaire was provided with satisfactory evaluations from the students regarding the organization and content of the practices. 84-86% of the students agreed that the exercises improved their knowledge in geomicrobiology and would like to attend similar laboratories in the future. Such response is the best indicator that the laboratory practice can be implemented in any undergraduate/graduate microbiology course to effectively teach basic geomicrobiology concepts to non-geology majors

    El problema semántico de la verosimilitud

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    Preliminary report on the July 10–11, 2015 explosive eruption at Volcán de Colima: Pyroclastic density currents with exceptional runouts and volume

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    http://dx.doi.org/10.1016/j.jvolgeores.2015.11.022Reporte preliminar acerca de una de las últimas etapas eruptivas de Volcán de Colima, análisis realizado a partir de técnicas de percepción remotaOn July 10–11, 2015 an eruption occurred at Colima volcano produced 10.5 km long pyroclastic density currents (PDCs) along the Montegrande, and 6.5 km long along the San Antonio ravines. The summit dome was destroyed and a new crater excavated and breached to the south. This new breach connects to a narrow channel that descends along Colima's southern flank and was used by a subsequent lava flow. The Montegrande PDCs represent the longest and hottest flow of this type recorded during the past 30 years but are still smaller in comparison to the 15-km long PDCs produced during the 1913 Plinian eruption. Data obtained from field reconnaissance, lahar monitoring stations, and satellite imagery suggest that at least six PDCs occurred. The two largest PDCs (H/L 0.2) were able to surmount topographic barriers or bends. Based on field reconnaissance and digital elevation models extracted from SPOT satellite imageries we estimate a minimum volume for the valley-pond and distal fan deposits of 4.5 × 106 m3. After one week, the deposits were still hot with burning trees on the surface and millimeter-sized holes from which fumes were emanating. The juvenile components of the deposits consist of gray dense blocks and vesicular dark-gray blocks and bombs with bread-crust textures and cooling joints. The mineral association of these rocks consists of plagioclase + clinopyroxene + orthopyroxene + FeTi-oxides ± olivine and resorbed hornblende in a dark glassy matrix that corresponds to an andesitic composition.CONACY

    Optimization of molecular detection of GD2 synthase mRNA in retinoblastoma

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    Extraocular dissemination is the main cause of death in patients with retinoblastoma in developing countries and there are few molecular markers that could be used for evaluation of minimal disseminated disease. The expression of the ganglioside GD2 is present in retinoblastoma cells metastatic to the bone marrow and the enzyme GD2 synthase activity is detected in neuroblastoma, which shares many phenotypic features with retinoblastoma. Our purpose was to optimize the detection of GD2 synthase expression by reverse transcription-polymerase chain reaction (RT-PCR) followed by nested-PCR in human retinoblastoma cell lines and patient samples. The optimization strategy was carried out by using the retinoblastoma cell lines Y79 and WERI-Rb1 and specific primers designed for the human sequence of the GD2 synthase mRNA. We detected GD2 synthase expression with at least 200 pg and 40 pg of total RNA extracted from cultured retinoblastoma cells, using a first round of RT-PCR amplification and a second round of nested-PCR, respectively. We have also confirmed the detection of GD2 synthase by RT-PCR and immunohistochemical expression of the ganglioside in human retinoblastoma tumors xenotransplanted in nude mice. In a study from tumor bank specimens from 8 retinoblastoma patients, we were able to demonstrate the presence of GD2 synthase mRNA in blood and cerebrospinal fluid samples in cases of extraocular dissemination of the tumor. The sequence was not detected in samples from children with low-risk disease or healthy adult volunteers. The detection of GD2 synthase mRNA through an optimized nested RT-PCR assay may be a promising tool for the assessment of minimal disseminated disease in enucleated patients.Fil: Laurent, Viviana Eunice. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrĂ­a "Juan P. Garrahan". Servicio de Hemato-OncologĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂ­a. Laboratorio de OncologĂ­a Molecular; ArgentinaFil: Otero, Laura L.. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂ­a. Laboratorio de OncologĂ­a Molecular; ArgentinaFil: Vazquez, Valeria. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂ­a. Laboratorio de OncologĂ­a Molecular; ArgentinaFil: Camarero, Sandra. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrĂ­a "Juan P. Garrahan"; ArgentinaFil: Gabri, Mariano Rolando. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂ­a. Laboratorio de OncologĂ­a Molecular; ArgentinaFil: Labrada, Maria. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrĂ­a "Juan P. Garrahan"; ArgentinaFil: Garcia de Davila, Maria Teresa. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrĂ­a "Juan P. Garrahan"; ArgentinaFil: Chantada, Guillermo Luis. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrĂ­a "Juan P. Garrahan". Servicio de Hemato-OncologĂ­a; ArgentinaFil: Alonso, Daniel Fernando. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂ­a. Laboratorio de OncologĂ­a Molecular; Argentin

    Integration of an [FeFe]-hydrogenase into the anaerobic metabolism of <i>Escherichia coli</i>

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    AbstractBiohydrogen is a potentially useful product of microbial energy metabolism. One approach to engineering biohydrogen production in bacteria is the production of non-native hydrogenase activity in a host cell, for example Escherichia coli. In some microbes, hydrogenase enzymes are linked directly to central metabolism via diaphorase enzymes that utilise NAD+/NADH cofactors. In this work, it was hypothesised that heterologous production of an NAD+/NADH-linked hydrogenase could connect hydrogen production in an E. coli host directly to its central metabolism. To test this, a synthetic operon was designed and characterised encoding an apparently NADH-dependent, hydrogen-evolving [FeFe]-hydrogenase from Caldanaerobacter subterranus. The synthetic operon was stably integrated into the E. coli chromosome and shown to produce an active hydrogenase, however no H2 production was observed. Subsequently, it was found that heterologous co-production of a pyruvate::ferredoxin oxidoreductase and ferredoxin from Thermotoga maritima was found to be essential to drive H2 production by this system. This work provides genetic evidence that the Ca.subterranus [FeFe]-hydrogenase could be operating in vivo as an electron-confurcating enzyme
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