91 research outputs found

    Low cost laboratories using ICT

    Get PDF
    En este trabajo se presentan los resultados de una propuesta educativa orientada a promover el desarrollo de un pensamiento crítico y un mayor interés por las ciencias experimentales. Con este fin desarrollamos propuestas de proyectos educativos susceptibles de ser destinadas a las aulas y laboratorios de las escuelas secundarias y primeros años de la universidad, que resaltan los aspectos metodológicos de las ciencias. Aquí, realizamos una compilación de varios proyectos, que ilustran formas de incorporar las tecnologías de la información y la comunicación (TIC) en diversos experimentos de ciencias, muchos de ellos publicados individualmente anteriormente, y que en conjunto se pueden utilizar para implementar un aula-laboratorio de bajo costo. Con TIC hacemos referencia a la convergencia de computadoras, sistemas audiovisuales, Internet, telefonía, y diversos equipos que se integran con algunos de ellos. Los proyectos intentan integrar áreas como física, matemática, química, informática, arte, etc. y apuntan a que los estudiantes puedan responder a las preguntas: ¿Cómo sabemos esto?, ¿Por qué creemos en aquello? Preguntas que ilustran la naturaleza del pensamiento científico. Nuestra contribución más significativa es haber desarrollado «aulas-laboratorios» de muy bajo costo, usando TIC. Con el advenimiento de programas como «Una Laptop por Niño» que se están implementando en varios países de Latinoamérica, resulta oportuno utilizar este recurso como base para generar laboratorios de bajo costo, que creemos pueden ser una herramienta útil para mejorar el aprendizaje de las ciencias, incentivar vocaciones y contribuir a desarrollar un pensamiento crítico, a la par de desarrollar habilidades con el uso de las TIC que pueden ser de utilidad en diversos ámbitos académicos y laborales.The results of an educational project aimed at promoting the development of critical thinking and promote interest in experimental sciences in High Schools and College students is presented. In this paper, we made a compilation of several activities, which ways of integrating information technology and communication (ICT) in various experiments of science, which together can be used to implement a low cost “classroom-laboratory”. With ICT we refer to the convergence of computers, software, audiovisual systems, Internet, telephone, and other equipment that integrates with some of these devices. To this end, several projects were developed, that can be transferred to high schools and colleges settings, with limited financial resources, as is frequent in Latin America. The projects highlight the methodological aspects of science and seek to integrate areas such as physics, mathematics, chemistry, computer science, art, etc. They aim to answer the questions: how do we know this?, why do we believe in that? These questions illustrate the nature of scientific thought. With the advent of programs such as “One Laptop per Child” that are being implemented in several Latin American countries, it is appropriate to use these resources as a basis to generate low cost laboratories. This contribution may be a useful tool to improve the quality of science learning and to encourage vocations in science and engineering. Furthermore, the development of a critical thinking, along with acquisition of skills in the use of ICT, can be essential in many academic and professional fields

    A Wear Analysis Carried On Connecting Rod Bearings From Internal Combustion Engines

    Get PDF
    In the present work, an analysis was carried out to know the wear modes present in connecting rod bearings from internal combustion engines. These mechanical elements were selected since they are exposed to different engineering failures such as incorrect assembly, severe loads, extreme temperatures, inadequate conditions, and loss of lubricity. In this particular case, the bearings that were selected had a service life of approximately 8 years. Different techniques such as SEM and optical microscopy, EDS analysis, hardness testing, and surface profilometry were used to characterize the unworn and worn bearings. Wear mechanisms such as sliding wear (scoring), fatigue wear with cracks where torn out material was clearly observed, discoloration areas, and two- and three-body abrasion wear (rubbing marks) were identified on the bearing surfaces

    Carbon-encapsulated iron nanoparticles as reusable adsorbents for micropollutants removal from water

    Full text link
    Adsorption represents the most plausible technology for micropollutants removal from water nowadays. Nevertheless, the regeneration of the saturated carbon materials is still an important challenge, being these solids in practice commonly disposed. This work aims at overcoming this issue by using innovative carbonencapsulated iron nanoparticles (CE-nFe). This material was synthesized by a low-cost and green method viz. hydrothermal carbonization (HTC), using olive mill wastewater as carbonaceous source. The solid was fully characterized by different techniques (magnetic properties, elemental analyses, N2-sorption isotherms, pHPZC, ICP, XRD and TEM). It showed a clear core-shell structure of around 40 nm in diameter. The core was mainly formed by zero-valent iron and the shell by graphitized carbon. Accordingly, it showed an essentially mesoporous structure, with a specific surface area of 169 m2 g−1 , and a clear hydrophobic character (pHPZC = 10). Its adsorption performance was investigated using three relevant micropollutants (diclofenac (DCF), sulfamethoxazole (SMX) and metronidazole (MNZ)). A very fast removal of the micropollutants was achieved (30 min at the most, with rate constants in the range of 0.11–0.41 g mg−1 min−1 ). The adsorption isotherms revealed the vertical packing of the adsorbate molecules onto the adsorbent active centers, being the data successfully described by the GAB model. The saturated adsorbents were effectively regenerated by heterogeneous Fenton oxidation, taking advantage of the iron core of CE-nFe and the opened mesoporous carbon shell. The regeneration efficiency increased with increasing the operating temperature (25–75 ◦C) and contact time (1–4 h), as well as the H2O2 dose up to 6 g L-1. The micropollutant nature affected the adsorbent regeneration yield in the order: SMX > DCF > MNZ, consistent with their reactivity towards Fenton oxidationThis research has been supported by the Spanish MINECO through the project CTM-2016-76454-R and by the CM through the project P2018/EMT-4341. M. Munoz and J. Nieto-Sandoval thank the Spanish MINECO for the Ramón y Cajal postdoctoral contract (RYC-2016-20648) and the FPI predoctoral grant (BES-2017-081346), respectivel

    Vacunación y eventos supuestamente atribuibles a vacunación o inmunización en estudiantes universitarios

    Get PDF
    La vacunación es la intervención que mayor impacto ha tenido en la salud después de la potabilización del agua. Las vacunas no están exentas de efectos adversos. Los eventos supuestamente atribuibles a vacunación o inmunización son: todo cuadro clínico que aparece luego de la administración de una vacuna y que eventualmente puede atribuirse a esta. En la Universidad Nacional de San Luis se realizó un Operativo de Vacunación en mayo del 2014. El objetivo fue determinar: vacunas administradas, eventos supuestamente atribuibles a vacunación o inmunización presentados, datos sociodemográficos y conocimiento sobre la notificación de eventos supuestamente atribuibles a vacunación o inmunización. Se realizó una encuesta a 84 personas vacunadas seleccionadas al azar de un total de 285; se incluyeron datos de edad, sexo, vacunas, número, tipo y síntomas de los eventos supuestamente atribuibles a vacunación o inmunización, tratamiento recibido y motivos de la no notificación. Los síntomas se clasificaron como: generales y locales; letales, graves, moderados, leves; y por necesidad de tratamiento o no. Resultados: edad: 18-45 años; sexo: femenino 72, masculino 12; vacunas: antigripal (48%), hepatitis B (24%), triple bacteriana acelular (15%), sarampión rubéola (7%) y doble bacteriana adultos (6%). Eventos supuestamente atribuibles a vacunación o inmunización (39): leves (38) y moderado (1). Síntomas: dolor, hinchazón, induración, malestar general y fiebre. Motivos para no notificar: desconocimiento de la existencia de la notificación (4), dónde y cómo realizar la notificación (7) y pensar que los eventos supuestamente atribuibles a vacunación o inmunización esperables no se deben notificar (28)

    Clinical characteristics of vulnerable populations hospitalized and diagnosed with COVID-19 in Buenos Aires, Argentina

    Get PDF
    There is not in Argentina publications regarding the presentation of patients with COVID-19 requiring hospitalized and emergency care in vulnerable populations (lower incomes and less education tend at greater risk for poor health status and healthcare access), and it has few reports in developing countries. The objective is to determine whether in the care of vulnerable patients, to succeed against COVID-19, multiple public health tools and interventions will be needed to minimize morbidity and mortality. The study is a prospective cohort investigation of patients with lab-confirmed COVID-19, who required to any of the Health Centers response from April 8, 2020, to August 18, 2020. In Buenos Aires Metropolitan Area (AMBA), April 8, 2020 the virus was identified in patients hospitalized in the "Southeast Network" (SN), AMBA. SN covering an area of 661 square kilometers, with 1.8 million inhabitants residing in urban, and rural areas. A total of 14 health centers with different levels of care complexity provide care to patients in the region. The information of each patient with COVID-19 evaluated by SN, was incorporated in an Epidemiological Dashboard. The investigation was designed and reported with consideration of observational studies in epidemiology. We describe the hospitals presentation and care of persons who required SN response and were ultimately diagnosed with COVID-19. From April 8, 2020, to August 18, 2020, were included 1495 patients with lab-confirmed COVID-19 in SN. A total of 58% patients were men, and the mean age (SD) was 48.9 (15.59) years. Eighty one percent patients with pre-existing diseases, most frequent hypertension and diabetes, but hypertension, chronic lung disease, and cardiovascular disease presented higher risk. A total of 13% were hospitalized in Intensive Therapy Unit. The mortality of the cohort was 9.77%. Mortality was higher for patients aged 65 or more (OR 5.09), and for those had some pre-existing disease (OR 2.61). Our observations are consistent with reports demonstrating older persons, and those with comorbidities have the highest risk of mortality related to COVID-19. However, unlike other reports from developed or some developing countries, the mortality in our study is lower. This finding may be related to age of our cohort is younger than other published. Also, the health system was able to respond to the demand.Fil: Yacobitti, A.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Otero, L.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Doldan Arrubarrena, V.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Arano, J.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Lage, S.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Silberman, M.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Zubieta, M.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Erbetta, I.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Danei, P.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; ArgentinaFil: Baeck, G.. Hospital Mi Pueblo; ArgentinaFil: Vallejos, V.. No especifíca;Fil: Cavalli, F.. No especifíca;Fil: Calderón, N.. Gobierno de la Provincia de Buenos Aires. Hospital Zonal General de Agudos Doctor Lucio Melendez.; ArgentinaFil: Di Gregorio, M.. Gobierno de la Provincia de Buenos Aires. Hospital Zonal General de Agudos Doctor Lucio Melendez.; ArgentinaFil: Hernandez, V.. Hospital Dr. Arturo Oñativia - Salta Capital.; ArgentinaFil: Bruno, D.. Hospital Dr. Arturo Oñativia - Salta Capital.; ArgentinaFil: Rodera, B.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Macherett, I.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Parisi, M.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Gallastegui, M.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Paz, A.. Municipalidad de Quilmes (buenos Aires). Hospital Sub Zonal Materno Infantil Doctor Eduardo Oller.; ArgentinaFil: Bernardi, R.. No especifíca;Fil: Azcárate, S.. Gobierno de la Provincia de Buenos Aires. Hospital Provincial Evita Pueblo.; ArgentinaFil: Hraste, A.. Gobierno de la Provincia de Buenos Aires. Hospital Provincial Evita Pueblo.; ArgentinaFil: Caridi, Délida Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; ArgentinaFil: Boechi, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; ArgentinaFil: Salgado, P.. Universidad de Buenos Aires. Rectorado. Instituto de Investigaciones en Salud Pública; ArgentinaFil: Kochen, Sara Silvia. Gobierno de la Provincia de Buenos Aires. Hospital de Alta Complejidad Cuenca Alta Doctor Nestor Carlos Kirchner.; Argentina. Universidad Nacional Arturo Jauretche; Argentina. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    The state of the Martian climate

    Get PDF
    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    Association between Ancestry-Specific 6q25 Variants and Breast Cancer Subtypes in Peruvian Women

    Get PDF
    Background: Breast cancer incidence in the United States is lower in Hispanic/Latina (H/L) compared with African American/ Black or Non-Hispanic White women. An Indigenous American breast cancer-protective germline variant (rs140068132) has been reported near the estrogen receptor 1 gene. This study tests the association of rs140068132 and other polymorphisms in the 6q25 region with subtype-specific breast cancer risk in H/Ls of high Indigenous American ancestry. Methods: Genotypes were obtained for 5,094 Peruvian women with (1,755) and without (3,337) breast cancer. Associations between genotype and overall and subtype-specific risk for the protective variant were tested using logistic regression models and conditional analyses, including other risk-associated polymorphisms in the region. Results: We replicated the reported association between rs140068132 and breast cancer risk overall [odds ratio (OR), 0.53; 95% confidence interval (CI), 0.47-0.59], as well as the lower odds of developing hormone receptor negative (HR-) versus HR+ disease (OR, 0.77; 95% CI, 0.61-0.97). Models, including HER2, showed further heterogeneity with reduced odds for HR+HER2+ (OR, 0.68; 95% CI, 0.51-0.92), HR-HER2+ (OR, 0.63; 95% CI, 0.44-0.90) and HR-HER2- (OR, 0.77; 95% CI, 0.56-1.05) compared with HR+HER2-. Inclusion of other risk-associated variants did not change these observations. Conclusions: The rs140068132 polymorphism is associated with decreased risk of breast cancer in Peruvians and is more protective against HR- and HER2+ diseases independently of other breast cancer-associated variants in the 6q25 region. Impact: These results could inform functional analyses to understand the mechanism by which rs140068132-G reduces risk of breast cancer development in a subtype-specific manner. They also illustrate the importance of including diverse individuals in genetic studies.National Institutes of HealthRevisión por pare

    MINDS. Abundant water and varying C/O across the disk of Sz 98 as seen by JWST/MIRI

    Get PDF
    MIRI/MRS on board the JWST allows us to probe the inner regions of protoplanetary disks. Here we examine the disk around the classical T Tauri star Sz 98, which has an unusually large dust disk in the millimetre with a compact core. We focus on the H2_2O emission through both its ro-vibrational and pure rotational emission. Furthermore, we compare our chemical findings with those obtained for the outer disk from Atacama Large Millimeter/submillimeter Array (ALMA) observations. In order to model the molecular features in the spectrum, the continuum was subtracted and LTE slab models were fitted. The spectrum was divided into different wavelength regions corresponding to H2_2O lines of different excitation conditions, and the slab model fits were performed individually per region. We confidently detect CO, H2_2O, OH, CO2_2, and HCN in the emitting layers. The isotopologue H218^{18}_2O is not detected. Additionally, no other organics, including C2_2H2_2, are detected. This indicates that the C/O ratio could be substantially below unity, in contrast with the outer disk. The H2_2O emission traces a large radial disk surface region, as evidenced by the gradually changing excitation temperatures and emitting radii. The OH and CO2_2 emission are relatively weak. It is likely that H2_2O is not significantly photodissociated; either due to self-shielding against the stellar irradiation, or UV-shielding from small dust particles. The relative emitting strength of the different identified molecular features point towards UV-shielding of H2_2O in the inner disk of Sz 98, with a thin layer of OH on top. The majority of the organic molecules are either hidden below the dust continuum, or not present. In general, the inferred composition points to a sub-solar C/O ratio (<0.5) in the inner disk, in contrast with the larger than unity C/O ratio in the gas in the outer disk found with ALMA.Comment: Submitted to A&A on May 25 2023. 18 pages, 11 figure
    corecore