69 research outputs found
Análisis comparativo de la influencia de la escoria de cobre como sustituto del agregado fino en porcentaje de peso, en la resistencia y consistencia de un concreto f’c=210 kg/cm2 elaborado con cementos tipo ip y tipo v, mediante pruebas de esclerometría y compresión axial de testigos sometidos a curado por inmersión.
Se investigó la influencia de la sustitución del agregado fino por escoria de cobre en
proporciones porcentuales de peso, mediante ensayos de índice de rebote y compresión axial
sobre probetas cilíndricas de concreto curadas por inmersión. Para fabricar las probetas se
empleó piedra chancada de 3/4'’ de la cantera de Huacarpay, arena de la cantera de Cunyac y
cementos tipo IP y tipo V, y se estudió la influencia de la EFC sobre la consistencia de la mezcla
fresca y resistencia a la compresión del concreto endurecido. Tras el procesamiento y análisis
de resultados se pudo apreciar que, a medida que se incrementan los porcentajes de arena
sustituida por escoria de cobre, el asentamiento de la mezcla sigue un patrón de crecimiento
lineal en proporción directa con el porcentaje de escoria. Asimismo, se encontró que con un
porcentaje de sustitución de 35% de agregado fino por escoria de cobre la resistencia a la
compresión se incrementa 65,974 kg/cm
2
en probetas fabricadas con cemento tipo IP; y 88,789
kg/cm
2
en probetas fabricadas con cemento tipo V.
Finalmente, se determinó el valor real de la dispersión del esclerómetro que fue empleado en
los ensayos, que es ±10% cuando se prueban especímenes fabricados con cemento tipo IP, y
±9% para probetas con cemento tipo V. También se encontraron ecuaciones, con su respectiva
dispersión, que permiten calcular el valor de la resistencia del concreto para cualquier
proporción de escoria de cobre dentro del rango experimental (0% a 50%).The influence of substitution of fine aggregate by copper slag in percentage proportions of
weight was investigated through sclerometer test and axial compression tests on cylindrical
concrete specimens cured by immersion. To manufacture the test pieces, Huacarpay quarry 3/4''
crushed stone, Cunyac quarry sand and IP and V types of cement were used, and the influence
of the EFC on the consistency of fresh concrete and compressive strength of hardened concrete
was studied. After processing and analyzing the results, it could be seen that the fresh concrete
slump follows a linear growth pattern in direct proportion to the percentage of slag when the
percentage of replacement of fine aggregate by slag increases. Also, it was found that with a
substitution percentage of 35% of fine aggregate per copper slag, the compressive strength
increases 65,974 kg/cm
2
in specimens made with IP type cement; and 88,789 kg/cm
in test
pieces manufactured with cement type V.
Finally, the real value of the dispersion of the sclerometer that was used in the tests was
determined, which is ± 10% when testing specimens manufactured with IP type cement, and ±
9% for specimens with type V cement. Equations were also found, with their respective
dispersion, that allows calculating the value of the concrete resistance for any proportion of
copper slag within the experimental range (0% to 50%).
2Tesi
Colaboración en entornos telemáticos de aprendizaje a distancia: Un caso de estudio en Matemáticas
En este trabajo se presenta una propuesta de modelo de entorno telemático, en este caso, para el aprendizaje/entrenamiento a distancia en la resolución de ecuaciones lineales. Destinado a profesores y alumnos de Educación Primaria y Secundaria. El entorno funciona apoyado sobre la tecnología que proporciona Internet e intranet, presenta un interfaz de aplicación que se ejecuta desde el Web. En esta aplicación se incluyen algunas técnicas para soportar colaboración asíncrona alumno-profesor y alumno-alumno, basadas en el empleo de bases de datos donde se registran todas las acciones, y aprovechando los recursos de Internet como mecanismos de comunicación asistida por computadoraThis paper presents a model of telematic environment for distance learning/training, to solve linear equations. This system was developed to help teachers in Primary and Secondary Education. The environment operates using the technology that provides Internet and intranet. It presents an application interface that runs on the Web supporting asynchronous collaboration between learners and teachers. This system, based on database technology, takes advantage from the Internet resources and the communication mechanisms that the computer network provides
Serum Selenium and Incident Cardiovascular Disease in the PREvención con DIeta MEDiterránea (PREDIMED) Trial: Nested Case-Control Study
Background: Selenium is an essential trace mineral with potential interest for cardiovascular disease (CVD) prevention owing to its antioxidant properties. Epidemiological data on selenium status and CVD remain inconsistent. The objective of this study was to ascertain whether low serum selenium (SSe) concentrations are related to an increased risk of a first CVD event in a population at high cardiovascular risk. Methods: We undertook a case-control study nested within the PREvencion con DIeta MEDiterranea (PREDIMED) trial. A total of 207 participants diagnosed with CVD (myocardial infarction, stroke, or cardiovascular death) during the follow-up period (2003-2010) were matched by sex, age, and intervention group to 436 controls by incidence density sampling. Median time between serum sample collection and subsequent CVD event occurrence was 0.94 years. SSe levels were determined using inductively coupled plasma mass spectrometry analysis. Covariates were assessed through validated questionnaires, in-person interviews, and medical record reviews. Conditional logistic regression was used to calculate multivariable-adjusted odds ratios (ORs). Results: Among women, the mean SSe concentration was lower in cases than in controls (98.5 mu g/L vs. 103.8 mu g/L; p = 0.016). In controls, SSe levels were directly associated with percentage of total energy intake from proteins and fish intake (p for linear trend < 0.001 and 0.049, respectively), whereas SSe concentrations were inversely associated with age, body mass index, and percentage of total energy intake from carbohydrates (p for linear trend < 0.001, 0.008 and 0.016 respectively). In the total group, we observed an inverse dose-response gradient between SSe levels and risk of CVD in the fully-adjusted model (highest vs. lowest quartile: OR = 0.47, 95% CI: 0.27-0.81; ptrend = 0.003). Conclusions: Among elderly individuals at high cardiovascular risk, high SSe concentrations within population reference values are associated with lower first CVD incidence
Association between serum copper levels and risk of cardiovascular disease: A nested case-control study in the PREDIMED trial
Background and aim: Certain trace elements have been associated with increased cardiovascular risk. The aim of this study was to evaluate the association between serum copper (S-Cu) levels and the risk of a first event of cardiovascular disease (CVD) in a population of older adults with high cardiovascular risk. Methods and results: We conducted a case-control study nested within the PREDIMED trial. During a median follow-up of 4.8 years, a total of 207 incident cases diagnosed with CVD were matched for sex, age, and intervention group with 436 controls. Personal interviews, reviews of medical records, and validated questionnaires were used to assess known CVD risk factors. Biological serum samples were collected annually. Inductively coupled plasma mass spectrometry analysis was used to determine S-Cu levels. Adjusted odds ratios were calculated using multivariate conditional logistic regression models. All participants had S-Cu levels within the reference values, 750 μg/L to 1450 μg/L. Among men, but not among women, the mean S-Cu concentration was higher in cases 1014.1 μg/L than in controls 959.3 μg/L; (p = 0.004). In men, the multivariable-adjusted odds ratio for CVD was 2.36 (95% CI 1.07-5.20 for the comparison of the highest vs. the lowest quartile; p for trend = 0.02), in women, it was 0.43 (95% CI 0.11-1.70; p for trend = 0.165). Conclusion: In older Spanish men with high cardiovascular risk, a significant association was observed between high S-Cu levels, but still within the reference values, and an increased risk of a first event of CVD. Our findings suggest a sex difference in CVD risk and S-Cu levels. To confirm this relationship and to analyze the differences observed between men and women, further studies are needed
Associations Between the Modified Food Standard Agency Nutrient Profiling System Dietary Index and Cardiovascular Risk Factors in an Elderly Population
Background: Helping consumers to improve the nutritional quality of their diet is a key public health action to prevent cardiovascular diseases (CVDs). The modified version of the Food Standard Agency Nutrient Profiling System Dietary Index (FSAm-NPS DI) underpinning the Nutri-Score front-of-pack label has been used in public health strategies to address the deleterious consequences of poor diets. This study aimed to assess the association between the FSAm-NPS DI and some CVD risk factors including body mass index (BMI), waist circumference, plasma glucose levels, triglyceride levels, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, and diastolic and systolic blood pressure. Materials and Methods: Dietary intake was assessed at baseline and after 1 year of follow-up using a 143-item validated semi-quantitative food-frequency questionnaire. Dietary indices based on FSAm-NPS applied at an individual level were computed to characterize the diet quality of 5,921 participants aged 55-75 years with overweight/obesity and metabolic syndrome from the PREDIMED-plus cohort. Associations between the FSAm-NPS DI and CVD risk factors were assessed using linear regression models. Results: Compared to participants with a higher nutritional quality of diet (measured by a lower FSAm-NPS DI at baseline or a decrease in FSAm-NPS DI after 1 year), those participants with a lower nutritional quality of diet (higher FSAm-NPS DI or an increase in score) showed a significant increase in the levels of plasma glucose, triglycerides, diastolic blood pressure, BMI, and waist circumference (beta coefficient [95% confidence interval]; P for trend) (1.67 [0.43, 2.90]; <0.001; 6.27 [2.46, 10.09]; <0.001; 0.56 [0.08, 1.05]; 0.001; 0.51 [0.41, 0.60]; <0.001; 1.19 [0.89, 1.50]; <0.001, respectively). No significant associations in relation to changes in HDL and LDL-cholesterol nor with systolic blood pressure were shown. Conclusion: This prospective cohort study suggests that the consumption of food items with a higher FSAm-NPS DI is associated with increased levels of several major risk factors for CVD including adiposity, fasting plasma glucose, triglycerides, and diastolic blood pressure. However, results must be cautiously interpreted because no significant prospective associations were identified for critical CVD risk factors, such as HDL and LDL-cholesterol, and systolic blood pressure
Associations Between the Modified Food Standard Agency Nutrient Profiling System Dietary Index and Cardiovascular Risk Factors in an Elderly Population
BackgroundHelping consumers to improve the nutritional quality of their diet is a key public health action to prevent cardiovascular diseases (CVDs). The modified version of the Food Standard Agency Nutrient Profiling System Dietary Index (FSAm-NPS DI) underpinning the Nutri-Score front-of-pack label has been used in public health strategies to address the deleterious consequences of poor diets. This study aimed to assess the association between the FSAm-NPS DI and some CVD risk factors including body mass index (BMI), waist circumference, plasma glucose levels, triglyceride levels, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, and diastolic and systolic blood pressure.Materials and MethodsDietary intake was assessed at baseline and after 1 year of follow-up using a 143-item validated semi-quantitative food-frequency questionnaire. Dietary indices based on FSAm-NPS applied at an individual level were computed to characterize the diet quality of 5,921 participants aged 55–75 years with overweight/obesity and metabolic syndrome from the PREDIMED-plus cohort. Associations between the FSAm-NPS DI and CVD risk factors were assessed using linear regression models.ResultsCompared to participants with a higher nutritional quality of diet (measured by a lower FSAm-NPS DI at baseline or a decrease in FSAm-NPS DI after 1 year), those participants with a lower nutritional quality of diet (higher FSAm-NPS DI or an increase in score) showed a significant increase in the levels of plasma glucose, triglycerides, diastolic blood pressure, BMI, and waist circumference (β coefficient [95% confidence interval]; P for trend) (1.67 [0.43, 2.90]; <0.001; 6.27 [2.46, 10.09]; <0.001; 0.56 [0.08, 1.05]; 0.001; 0.51 [0.41, 0.60]; <0.001; 1.19 [0.89, 1.50]; <0.001, respectively). No significant associations in relation to changes in HDL and LDL-cholesterol nor with systolic blood pressure were shown.ConclusionThis prospective cohort study suggests that the consumption of food items with a higher FSAm-NPS DI is associated with increased levels of several major risk factors for CVD including adiposity, fasting plasma glucose, triglycerides, and diastolic blood pressure. However, results must be cautiously interpreted because no significant prospective associations were identified for critical CVD risk factors, such as HDL and LDL-cholesterol, and systolic blood pressure
Healthcare workers hospitalized due to COVID-19 have no higher risk of death than general population. Data from the Spanish SEMI-COVID-19 Registry
Aim To determine whether healthcare workers (HCW) hospitalized in Spain due to COVID-19 have a worse prognosis than non-healthcare workers (NHCW). Methods Observational cohort study based on the SEMI-COVID-19 Registry, a nationwide registry that collects sociodemographic, clinical, laboratory, and treatment data on patients hospitalised with COVID-19 in Spain. Patients aged 20-65 years were selected. A multivariate logistic regression model was performed to identify factors associated with mortality. Results As of 22 May 2020, 4393 patients were included, of whom 419 (9.5%) were HCW. Median (interquartile range) age of HCW was 52 (15) years and 62.4% were women. Prevalence of comorbidities and severe radiological findings upon admission were less frequent in HCW. There were no difference in need of respiratory support and admission to intensive care unit, but occurrence of sepsis and in-hospital mortality was lower in HCW (1.7% vs. 3.9%; p = 0.024 and 0.7% vs. 4.8%; p<0.001 respectively). Age, male sex and comorbidity, were independently associated with higher in-hospital mortality and healthcare working with lower mortality (OR 0.211, 95%CI 0.067-0.667, p = 0.008). 30-days survival was higher in HCW (0.968 vs. 0.851 p<0.001). Conclusions Hospitalized COVID-19 HCW had fewer comorbidities and a better prognosis than NHCW. Our results suggest that professional exposure to COVID-19 in HCW does not carry more clinical severity nor mortality
Cualificación en los Objetivos establecidos en la Agenda 2030 de estudiantes y profesores en el Máster Universitario en Profesor de Educación Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanza de Idiomas (MUPES)
Memoria ID2022-157 Ayudas de la Universidad de Salamanca para la innovación docente, curso 2022-2023
COVID-19 vaccine failure
COVID-19 affects the population unequally with a higher impact on aged and
immunosuppressed people. Hence, we assessed the effect of SARS-CoV-2 vaccination
in immune compromised patients (older adults and oncohematologic patients),
compared with healthy counterparts. While the acquired humoral and cellular memory
did not predict subsequent infection 18 months after full immunization, spectral and
computational cytometry revealed several subsets within the CD8+ T-cells, B-cells, NK
cells, monocytes and CD45RA+
CCR7- Tγδ cells differentially expressed in further
infected and non-infected individuals not just following immunization, but also prior to
that. Of note, up to 7 subsets were found within the CD45RA+
CCR7-
Tγδ population with
some of them being expanded and other decreased in subsequently infected individuals.
Moreover, some of these subsets also predicted COVID-induced hospitalization in
oncohematologic patients. Therefore, we hereby have identified several cellular subsets
that, even before vaccination, strongly related to COVID-19 vulnerability as opposed to
the acquisition of cellular and/or humoral memory following vaccination with SARS-CoV2 mRNA vaccines.This study has been funded through Programa Estratégico Instituto de Biología y
Genética Molecular (IBGM Junta de Castilla y León. Ref. CCVC8485), Junta de Castilla
y León (Proyectos COVID 07.04.467B04.74011.0) and the European Commission –
NextGenerationEU (Regulation EU 2020/2094), through CSIC's Global Health Platform
(PTI Salud Global; SGL21-03-026 and SGL2021-03-038)N
Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality
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