RESUMO

As the main components of the building envelope, construction materials have a straight relation with air contaminants from anthropogenic origins. Titanium dioxide has been recently applied in construction industry products since its photocatalytic properties can be used for pollutant degradation purposes. This study evaluated the performance of cement-based mortars with the incorporation of TiO2 nanoparticles and mineral admixtures. Six mortar compositions were defined by considering two reference mixes (with and without TiO2 incorporation), two mineral admixtures (bentonite and metakaolin) as partial cement replacement and one waste from ornamental stone processing in two levels of partial substitution of natural sand. Consistency index, density, and entrained air content of mixtures were investigated at fresh state. Compressive strength, water absorption, sorptivity, and micrographs from scanning electron microscopy were used to characterize mortars at hardened state. It was observed that incorporation of TiO2 does not considerably change mortar's properties at fresh and hardened state, despite a denser microstructure and improved interfacial transition zone. In general, the relation between the water-to-cement ratio and porosity on the performances of TiO2-added mortars was shown, which is strongly related to their photocatalytic efficiency. Metakaolin mixtures were more efficient to NO conversion, and high selectivity was observed for the bentonite mortars.

Assuntos

RESUMO

This paper aimed to analyze the reduction in the ballast layer permeability simulated in a laboratory in saturated conditions by the presence of rock dust as a contaminant of three types of rocks explored in different deposits in the northern region of the state of Rio de Janeiro, Brazil, through laboratory testing relating the physical properties of rock particles before and after sodium sulfate attack. Sodium sulfate attack is justified by the proximity of some sections of the planned EF-118 Vitória-Rio railway line to the coast and of the sulfated water table to the ballast bed, which could degrade the material used and compromise the railway track. Granulometry and permeability tests were performed to compare ballast samples with fouling rates of 0, 10, 20, and 40% rock dust by volume. A constant head permeameter was used to analyze hydraulic conductivity and establish correlations between the petrography and mercury intrusion porosimetry of the rocks, namely two types of metagranite (Mg1 and Mg3) and a gneisse (Gn2). Rocks, such as Mg1 and Mg3, with a larger composition of minerals susceptible to weathering according to petrography analyses, tend to be more sensitive to weathering tests. This, in conjunction with the climate in the region studied, with average annual temperature and rainfall of 27 °C and 1200 mm, could compromise track safety and user comfort. Additionally, the Mg1 and Mg3 samples showed greater percentage variation in wear after the Micro-Deval test, which could damage the ballast due to the considerable changeability of the material. The mass loss caused by abrasion due to the passage of rail vehicles was assessed by the Micro-Deval test, with Mg3 (intact rock) declining from 8.50 ± 1.5 to 11.04 ± 0.5% after chemical attack. However, Gn2, which exhibited the greatest mass loss among the samples, showed no significant variation in average wear, and its mineralogical characteristics remained almost unchanged after 60 sodium sulfate cycles. These aspects, combined with its satisfactory hydraulic conductivity rate, indicate that Gn2 is suitable for use as railway ballast in the EF-118 railway line.

RESUMO

In recent years, the demand for clean water has been growing all over the world despite the different threats posed, including increasing pollution, increasing deforestation and climate change. Industrial activity is the second largest consumer of water, so highly industrialized regions are more susceptible to water stress. In this sense, reuse strategies have been progressively discussed and used around the world; however, in Brazil there is still place for many advances, whether due to lack of incentives, cultural issues in society, or poor regulation of the subject. The objective of this work was to carry out a diagnosis of raw water uptake by industries in one Hydrographic Region of the state of Rio de Janeiro and to propose a discussion on the adoption of water reuse practices for non-potable purposes from the use of treated effluents. A survey of the theoretical framework on the subject was carried out, as well as an analysis of sustainability indicators and reports of the companies, including the current licensing processes of large undertakings consuming water resources. With this study, it was possible to obtain the average cost of implementing a water reuse unit for an industry in the state of Rio de Janeiro-Brazil, which, despite still being expensive, has a strong tendency to use due to world water shortages. Finally, it was concluded that the state of Rio de Janeiro has a threat of water scarcity that could be aggravated in the coming years, if measures and investments in supply alternatives are not adopted (water reuse), and improvement in all stages of water management water resources.

Assuntos

RESUMO

Civil construction is one of the most resource-consuming sectors in the world. For this reason, the last years have witnessed the study of reusing industrial residues in building materials. The ornamental stone processing industry has a considerable environmental liability related to residue generation during the cutting stages of granite blocks. The objective of this work is to analyze the viability of incorporating granite residues, up to 100%, to substitute sand in coating mortars for building construction. Mortars without residue, as control, and incorporated with 20, 40, 60, 80, and 100% of granite residue were subjected to consistency tests, incorporated air and water retention together with the rheological characterization using the squeeze-flow and the dropping-ball methods. The results show that mortars with 40% granite residues presented greater plastic deformation, helping their applicability by also presenting improved technological properties in the fresh state.

RESUMO

The 2016 undergraduate medical degree curriculum at the Facultad de Estudios Superiores Iztacala of the Universidad Nacional Autónoma de México (UNAM) is presented. It is the result of a long institutional reflection and academic dialog process of approximately three years, which culminated in its approval by UNAM's Academic Council for the Biology, Chemistry, and Health Sciences areas on January 25, 2016. Its most relevant characteristics are: modular organization, four knowledge areas (biomedical, methodological, socio-psychological, and humanistic and medical practice), and new modules such as Seminar of socio-psycho-biological integration; Genetics and molecular biology; Biochemistry and cellular biology; Pharmacological basis of therapeutics; Infectious diseases, microbiology and parasitology; Medical ethics; Public health; and Evidence-based medicine - clinical epidemiology. To achieve a more flexible curriculum, optional modules were included. To make possible the curricular change, improving the teaching strategies, innovating the learning assessment methods, supporting the training and updating of the teaching staff, and establishing a curriculum development committee for following up and evaluating the program, are necessary. Curricular changes are difficult and complex processes; they suppose challenges and opportunities. It is mandatory to plan them carefully and sensitively to allow a successful transition and avoid conflicts for the students, the teachers and the institution.

Assuntos

RESUMO

OBJECTIVE: to explore the agreement of medical students (MS) with the statement "I liked participating in my peers' assessment" and the explanations why. METHODS: the peer assessment of 411 MS who participated consisted in assessing audiovisual lectures presented by their classmates using rubrics. Then, they classified their grade of agreement with the statement "I liked participating in my peers' assessment" and briefly explained why. An analysis of content was performed, response categories were classified, and a simple count of the number of responses in each category was done. RESULTS: most of the MS (68 %) liked participating in peer assessment completely or partially. The major negative explanations were the concern that affective considerations would influence the grades (18 %), and the perception of unfair assessments (12.2 %). The positive ones were the perception of a more fair assessment (11 %), and the idea that it provides feedback for improvement (9.5 %). CONCLUSIONS: knowing the explanations given by the MS to support their agreement with the pleasure for participating in peer assessment allows a more adequate approach to conflicts.

Assuntos

RESUMO

OBJECTIVE: To measure the acceptance of problem based learning (PBL), to find out if they consider that spending extra-time is worthy, how they perceive their own learning, and how it correlated with other learning parameters. METHODS: After exposure to PBL during one semester, a cross sectional survey based on Likert-type scale was conducted to measure the students' opinion about PBL acceptance and perception of their own learning. The sample was 268 (65%) females and 143 (35%) males from the 3rd semester of the medical school. The Spearman's correlation was used for analysis. RESULTS: PBL was considered to be useful or very useful for their learning to 89% of the students. The PBL used longer time working after the classroom activities. The extra-time spent in the course was considered worthy by 77%. Perception of their own learning correlated with the marks that they obtained (rho=0.202, p<0.0001), and with the acceptance of PBL (rho=0.291, p<0.0001). CONCLUSIONS: Students' acceptance of PBL was corroborated. Perception of a better learning correlated with higher marks and, with better acceptance of PBL and with the perception that the additional time spent was worth while.

Assuntos

Assuntos

Assuntos

Assuntos

RESUMO

OBJECTIVE: Assess the degree to which medical students accept and consider useful the techniques of problem based learning (PBL) and evaluation among peers. Analyze the association between the number of PBL clinical cases reviewed and the students' perception about their own learning in a basic course. METHODS: A questionnaire was administered to 334 students enrolled in the third semester of medical school (Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México). Questions included acceptability of PBL, peer evaluation, and their perception about the usefulness of these techniques after having used them during the school year. We used a Likert scale to measure opinions on the degree of usefulness of the PBL, perception of their own learning, and the acceptance of the notion that evaluation activities evaluation among peers promote justice and favor the student's character formation. We measured the association of these variables with the number of clinical cases studied using Spearman's rank correlation coefficient. RESULTS: Most of the students considered that PBL method is useful (82%) and that evaluation activities among peers promote justice and character formation (70%). Students who reviewed more PBL cases considered the PBL activities more useful (rho = 0.489, p < 0.0001), and perceived that they achieved a better learning experience (rho = 0.200, p < 0.0001). CONCLUSIONS: Results show a fair acceptance by the students of the PBL method and activities of peer evaluation. The number of clinical cases reviewed during the course correlated with considering the PBL to be a useful method and perceiving a better learning experience. Our results support the inclusion of PBL and peer evaluation in the medical school curricula.

Assuntos

RESUMO

Objetivo: Conocer el grado en el que los estudiantes aceptan y consideran útiles las técnicas de aprendizaje basado en problemas (ABP) y de evaluación entre pares. Analizar la asociación entre el número de casos clínicos de ABP revisados en el curso con la percepción de los estudiantes acerca de su aprendizaje, en un módulo de los ciclos básicos de la carrera de médico cirujano. Métodos: Se aplicó un cuestionario en forma anónima y voluntaria a 334 estudiantes de 12 grupos que cursaron un módulo predominantemente teórico del tercer ciclo de la carrera de médico cirujano en la Facultad de Estudios Superiores Iztacala, para evaluar su aceptación y percepción de la utilidad del ABP y de la evaluación entre pares, después de haber usado estas técnicas durante el curso semestral. La opinión sobre el grado de utilidad del ABP, la percepción del propio aprendizaje y el grado de aceptación de la noción de que las actividades de evaluación entre pares son justas y formativas se midieron mediante escalas ordinales tipo Likert; la asociación de estas variables con el número de casos clínicos revisados en el semestre se analizó mediante el coeficiente de correlación por rangos de Spearman. Resultados: La mayoría de los estudiantes consideró que el método de ABP es útil (82%) y que las actividades de evaluación entre pares son justas y formativas (70%). Los estudiantes que revisaron un número mayor de casos de ABP consideraron más útiles las actividades de ABP (rho = 0.489, p < 0.0001) y percibieron que habían tenido un mejor aprendizaje sobre inmunología (rho = 0.200, p < 0.0001). Conclusiones: Los resultados muestran una buena aceptación del método de ABP y de la evaluación entre pares por parte de los estudiantes. El número de casos de ABP revisados durante el semestre correlacionó con que se consideraran útiles las actividades de ABP y con la percepción de un mejor aprendizaje. Los resultados apoyan la aplicación de las técnicas de ABP y evaluación entre pares en cursos futuros.

OBJECTIVE: Assess the degree to which medical students accept and consider useful the techniques of problem based learning (PBL) and evaluation among peers. Analyze the association between the number of PBL clinical cases reviewed and the students' perception about their own learning in a basic course. METHODS: A questionnaire was administered to 334 students enrolled in the third semester of medical school (Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México). Questions included acceptability of PBL, peer evaluation, and their perception about the usefulness of these techniques after having used them during the school year. We used a Likert scale to measure opinions on the degree of usefulness of the PBL, perception of their own learning, and the acceptance of the notion that evaluation activities evaluation among peers promote justice and favor the student's character formation. We measured the association of these variables with the number of clinical cases studied using Spearman's rank correlation coefficient. RESULTS: Most of the students considered that PBL method is useful (82%) and that evaluation activities among peers promote justice and character formation (70%). Students who reviewed more PBL cases considered the PBL activities more useful (rho = 0.489, p < 0.0001), and perceived that they achieved a better learning experience (rho = 0.200, p < 0.0001). CONCLUSIONS: Results show a fair acceptance by the students of the PBL method and activities of peer evaluation. The number of clinical cases reviewed during the course correlated with considering the PBL to be a useful method and perceiving a better learning experience. Our results support the inclusion of PBL and peer evaluation in the medical school curricula.

Assuntos

Assuntos

Assuntos

Assuntos

Assuntos

RESUMO

É relatado o caso clínico de uma criança, previamente hígida, que evoluiu com manifestações neurológicas inespecíficas. O diagnóstico obtido, após investigação intervencionista, foi de neurotuberculose. Instituído tratamento preconizado pela Organização Mundial de Saúde (OMS), com boa resposta clínica. O objetivo é alertar os pediatras para inclusão da neurotuberculose no diagnóstico diferencial de doenças infecciosas e lesões expansivas do sistema nervoso central.

Related a clinical case of a child, previously healthy, who evaluated with unespecific neurological manifestations. The diagnosis obtained, after interventionist investigation, was neurotuberculosis. Instituted treatment extoled by OMS, with good clinical response. The goal is advertise pediatrics to add neurotuberculosis to differential diagnosis of infecctious diseases and expansive lesions of central nervous system.

Assuntos

RESUMO

Con la finalidad de conocer los diagnósticos de egreso y la letalidad que se registra entre los adolescentes atendidos en un servicio de pediatría médica de un hospital de tercer nivel, se revisaron los expedientes clínicos de los ingresos habidos en dos años (del 1o. de enero de 1990 al 31 de diciembre de 1992). Como principales diagnósticos se encontraron: insuficiencia renal crónica, 254 casos (11.97 por ciento); leucemia 61 casos, (2.85 por ciento); asma bronquial, 61 casos (2.85 por ciento); comunicación interventricular, 55 casos (2.52 por ciento). Como primera causa de letalidad se encontró a la leucemia con 30 casos (30.0 por ciento); en el segudo lugar estuvo la insuficiencia renal crónica, 11 casos (8.8 por ciento); el lupus eritematoso sistémico se observó en nueve casos (7.2 por ciento); insuficiencia renal aguda, ocho casos (6.4 por ciento) y traumatismo craneoencefálico seis casos (4.8 por ciento). Se comentan los hallazgos haciendo notar el predominio de los padecimientos crónicos.

Assuntos

RESUMO

Con la finalidad de estandarizar el test serológico y el nivel de corte para descartar a los infectados por T. cruzi en donantes de sangre se realizo el presente taller. entre las conclusiones mas importantes se destacan los siguientes acuerdos: 1) Utilizar el test de HAI en una dilucion 1/8 en todos los bancos de sangre, 2) Realizacion de talleres periodicos de padronizacion serologica, 3) Recomendar a los profesionales de la salud el uso racional de la transfusion sanguinea y 4) Soliciatr al S.N.S. la actualizacion de la resolucion ministerial sobre la reglamentacion del uso del violeta de genciana para prevenir la transmision del T. cruzi por via transfusional.

Assuntos

RESUMO

Se aplicó una encuesta sobre la investigación médica a 310 personas: deseo de dedicarse a ella, dedicación actual o previa a labores de investigación y opinión sobre la necesidad de un curso de investigación en el currículum de la carrera de médico cirujano. Los participantes se dividieron en siete grupos de conformidad con su labor principal: profesores, administrativos, médicos de primer, segundo y tercer nivel de atención, residentes y estudiantes de medicina. La opinión de los participantes fue favorable a la investigación médica: 93,5% de ellos pensaron que les hubiera sido útil recibir un curso de investigación durante sus estudios de pregrado; 94,8% que es necesario un curso de introducción a la investigación científica en el currículum de licenciatura, aunque 23,5% de los administrativos (cifra significativamente diferente de la del resto de los grupos, p < 0,05), opinaron que el curso es innecesario. Por los datos obtenidos, los autores consideran que debe incluirse un curso de introdución a la investigación científica en el plan de estudios de la carrera de médico cirujano

Assuntos