Abstract A continuous increase in levels of atmospheric pollution and emission restrictions has forced scientists and engineers to adopt new strategies to improve and develop internal combustion engines. One strategy is based on the development of new simulation methodologies using computational fluid dynamic (CFD) techniques, proposed in the present article. In this study,the dynamic loop methodology with ANSYS Fluent code is proposed to perform the numerical simulation ofa four-stroke spark ignition engine. The complexity of the real case was first simplified with three-dimensional CAD geometry, which was then discretized in ANSYS Meshing, whereby a hybrid mesh was created using prismatic and tetrahedral elements. Simulations for in-cylinder analyses were performed in cold flow and employing common flow parameters, such as swirl and tumble. The mesh quality results were classified as good or excellent, being higher than 0.79 for orthogonal quality criteria and lower than 0.36 for skewness criteria. Turbulent effects were introduced concerning the opening and closing of the valves. It was found that the turbulence increases during the intake stroke up to 90°, and during the power stroke, wherein the of the piston bowl, had a great contributionthat can be seen from the swirl and tumble profile for the engine cycle. In the case of the turbulence intensity, a sharp increase was registered during the admission step up to 90°, at which point the turbulence intensity was 4.0. It canbe concluded that this is an innovative approach, capable of simulating the engine motion profile in cold flow.

RESUMEN Objetivos. Evaluar las comorbilidades asociadas a la mortalidad en pacientes adultos hospitalizados por COVID-19 de diferentes grupos de edad en hospitales de Lima y Callao. Materiales y métodos. En este estudio de cohorte retrospectiva analizamos datos de pacientes adultos hospitalizados por COVID-19, notificados al Sistema Nacional de Vigilancia Epidemiológica del Ministerio de Salud de Perú de marzo a octubre del 2020. Se estimaron riesgos relativos con intervalos de confianza al 95% mediante modelos de regresión de Poisson con varianza robusta para evaluar las comorbilidades asociadas a la mortalidad por grupos de edad: jóvenes (18-29 años), adultos (30-59 años) y mayores (≥60 años). Resultados. Se incluyeron 2366 jóvenes, 23781 adultos y 25356 adultos mayores en el análisis. Los adultos mayores presentaron la mortalidad más alta (63,7%) en comparación con adultos (27,1%) y jóvenes (8,5%). Independientemente del grupo de edad, la presencia de enfermedad neurológica, enfermedad renal, enfermedad hepática y cáncer se asoció a un mayor riesgo de mortalidad. Adicionalmente, la enfermedad cardiovascular fue también un factor de riesgo en los jóvenes; la obesidad, la diabetes, la enfermedad cardiovascular, la enfermedad pulmonar crónica y la inmunodeficiencia en los adultos; y la obesidad y la enfermedad pulmonar crónica en los mayores. Conclusiones: Independientemente de los grupos de edad, los individuos con enfermedad neurológica crónica, enfermedad renal, enfermedad hepática y cáncer tendrían un alto riesgo de morir por la COVID-19.

ABSTRACT Objectives. To evaluate comorbidities associated with mortality in adult patients hospitalized due to COVID-19 in hospitals in Lima and Callao. Materials and methods. In this retrospective cohort study, we analyzed data from adult patients hospitalized due to COVID-19 reported to the National Epidemiological Surveillance System of the Peruvian Ministry of Health from March to October 2020. We estimated relative risks with 95% confidence intervals using Poisson regression models with robust variance to assess comorbidities associated with mortality by age group: young adults (18-29 years), adults (30-59 years) and older adults (≥60 years). Results. We included 2366 young adults, 23,781 adults and 25,356 older adults. Older adults had the highest mortality (63.7%) compared to adults (27.1%) and young adults (8.5%). Regardless of age group, the presence of neurological disease, renal disease, liver disease, and cancer was associated with an increased risk of mortality. Additionally, cardiovascular disease was also a risk factor in young adults; obesity, diabetes, cardiovascular disease, chronic lung disease, and immunodeficiency in adults; and obesity and chronic lung disease in the elderly. Conclusions. Regardless of age groups, individuals with chronic neurologic disease, renal disease, liver disease, and cancer were at high risk of death from COVID-19.

ABSTRACT Objectives. To evaluate comorbidities associated with mortality in adult patients hospitalized due to COVID-19 in hospitals in Lima and Callao. Materials and methods. In this retrospective cohort study, we analyzed data from adult patients hospitalized due to COVID-19 reported to the National Epidemiological Surveillance System of the Peruvian Ministry of Health from March to October 2020. We estimated relative risks with 95% confidence intervals using Poisson regression models with robust variance to assess comorbidities associated with mortality by age group: young adults (18-29 years), adults (30-59 years) and older adults (≥60 years). Results. We included 2366 young adults, 23,781 adults and 25,356 older adults. Older adults had the highest mortality (63.7%) compared to adults (27.1%) and young adults (8.5%). Regardless of age group, the presence of neurological disease, renal disease, liver disease, and cancer was associated with an increased risk of mortality. Additionally, cardiovascular disease was also a risk factor in young adults; obesity, diabetes, cardiovascular disease, chronic lung disease, and immunodeficiency in adults; and obesity and chronic lung disease in the elderly. Conclusions. Regardless of age groups, individuals with chronic neurologic disease, renal disease, liver disease, and cancer were at high risk of death from COVID-19.

RESUMEN Objetivos. Evaluar las comorbilidades asociadas a la mortalidad en pacientes adultos hospitalizados por COVID-19 de diferentes grupos de edad en hospitales de Lima y Callao. Materiales y métodos. En este estudio de cohorte retrospectiva analizamos datos de pacientes adultos hospitalizados por COVID-19, notificados al Sistema Nacional de Vigilancia Epidemiológica del Ministerio de Salud de Perú de marzo a octubre del 2020. Se estimaron riesgos relativos con intervalos de confianza al 95% mediante modelos de regresión de Poisson con varianza robusta para evaluar las comorbilidades asociadas a la mortalidad por grupos de edad: jóvenes (18-29 años), adultos (30-59 años) y mayores (≥60 años). Resultados. Se incluyeron 2366 jóvenes, 23781 adultos y 25356 adultos mayores en el análisis. Los adultos mayores presentaron la mortalidad más alta (63,7%) en comparación con adultos (27,1%) y jóvenes (8,5%). Independientemente del grupo de edad, la presencia de enfermedad neurológica, enfermedad renal, enfermedad hepática y cáncer se asoció a un mayor riesgo de mortalidad. Adicionalmente, la enfermedad cardiovascular fue también un factor de riesgo en los jóvenes; la obesidad, la diabetes, la enfermedad cardiovascular, la enfermedad pulmonar crónica y la inmunodeficiencia en los adultos; y la obesidad y la enfermedad pulmonar crónica en los mayores. Conclusiones: Independientemente de los grupos de edad, los individuos con enfermedad neurológica crónica, enfermedad renal, enfermedad hepática y cáncer tendrían un alto riesgo de morir por la COVID-19.

ABSTRACT Introduction. The entry of American/Asian DENV-2 lineage II in the Loreto region of the Peruvian Amazon coincided with a sudden increase in dengue cases requiring hospitalization. However, official statistics reported few severe cases. It is postulated that there was an underreporting of severe cases in the official reports of the Ministry of Health. Objectives. To determine the frequency of patients with signs of severity among patients hospitalized for probable dengue fever during the 2011 outbreak at the Iquitos Hospital, Peru. Methods. A longitudinal study was carried out applying a daily checklist on the presence of signs of severity during hospital stay to a group of patients hospitalized in the dengue unit of the Iquitos hospital. Results. Of 178 patients evaluated, 66 (37%, CI: 29.9-44.6%) presented some sign of severity, mostly due to shock (75,7%). This result contrasts with the number of patients with severe dengue reported by the Ministry of Health during 2011 in the Loreto region. Conclusion. Approximately one third of the patients who were hospitalized with a diagnosis of dengue during the outbreak of American/Asian DENV-2 lineage II developed signs of severity during their hospitalization.

RESUMEN Introducción. El ingreso del linaje II del DENV-2 americano/asiático en la región Loreto de la Amazonia Peruana, coincidió con un incremento súbito de los casos de dengue con necesidad de hospitalización. Sin embargo, las estadísticas oficiales reportaron pocos casos graves. Se postula, que existió una subnotificación de los casos graves en los reportes oficiales del Ministerio de Salud. Objetivos. Conocer la frecuencia de pacientes con signos de gravedad entre los pacientes hospitalizados por dengue probable durante el brote del 2011 en el Hospital Iquitos, Perú. Métodos. Se realizó un estudio longitudinal, aplicando una lista de chequeo diaria, sobre la presencia de signos de gravedad durante la estancia hospitalaria, a un grupo de pacientes hospitalizados en la unidad de dengue del Hospital Iquitos. Resultados. De 178 pacientes evaluados 66 (37%, IC: 29,9 - 44,6%) presentaron algún signo de gravedad, la mayor parte por shock (75,7%). Este resultado contrasta con el número de pacientes con dengue grave reportado por el Ministerio de Salud durante el año 2011 en la región Loreto. Conclusión. Aproximadamente un tercio de los pacientes que fueron hospitalizados con el diagnostico de dengue, durante el brote por el linaje II del DENV-2 americano/asiático, desarrollaron signos de gravedad durante su hospitalización.