Monitoreo de Condición en Motores de Combustión Interna Monocilíndricos con Base en Adquisición y Procesamiento de Señales Experimentales

In recent years, condition monitoring based on signal analysis has become a valuable tool for the diagnosis of internal combustion engines. In this paper the experimental design for the ICE monitoring condition, based on signal analysis, is presented. The experimental configuration was development for the analysis of signals from ICE in order to monitor their condition. The conduced case study consists on the monitoring condition of a single-cylinder engine, operating under regular conditions and different speeds. The instrumentation, the adquisition systems as well as the signals analysis are also presented. The adquired signals were: engine block vibration, in-cylinder pressure and crankshaft speed. The mentioned signals were analyzed and processed by FFT and Rigid Regression. It was possible to obtain the frequency spectrum of the vibration signal and reconstruct the in-cylinder pressure of the single-cylinder engine. The presented configuration can be taken as a basis for the evaluation of others engines and for improving the schemes of monitoring condition.Keywords: Internal combustion engines, condition monitoring, signal acquisition, signal processing

Bird community effects on avian malaria infections

In community assembly processes, interspecific interactions play an important role in shaping community diversity, especially at the local scale. Changes in species richness or abundance can modify local infectious disease dynamics, either reducing or increasing the risk of transmission within the community. This study evaluates the effects of bird community on avian haemosporidians infections in a Neotropical region. Bird samples were collected from areas surrounding three dams, and molecular analysis were performed to identify blood-parasitic haemosporidia infecting the birds. Generalized linear models were used to analyze the relationships between the bird community and the prevalence, number of infections, and richness of avian haemosporidian lineages. Non-significant effects of bird community dominance and richness on the prevalence of avian parasites and the number of infections of Haemoproteus were found. However, there was evidence of an amplification effect. Host dominance was associated with the total number of infections, the number Plasmodium infections and the expected richness of Plasmodium lineages, while the expected richness of Haemoproteus lineages was associated with the richness of bird species. These findings highlight the role of host community dominance and richness in the dynamics of parasite infections, potentially influenced by the availability of competent hosts. This study contributes significantly to our understanding of blood parasite diversity in tropical birds within a relatively understudied region of South America.This research was funded by Empresas Públicas de Medellín (EPM) and the Universidad de Antioquia through the cooperation Grant CT-2017–001714. JMP was financed by the grant PID2020-118205GB-I00 from MCIN/ AEI/10.13039/501100011033 of the Spanish Ministry of Science and Innovation

Combustion pressure estimation method of a spark ignited combustion engine based on vibration signal processing

An estimation method of the combustion chamber pressure, in an internal combustion engine, based on the processing of the vibration (acceleration) signal of the cylinder head, at constant speed and no load conditions is presented in this paper. The model is created based on the comparison of the vibration and pressure signals around the peaks of highest vibration, after a preprocessing and filtering of the signal using the most similar frequency bands between the sources. A polynomial regression is used between the selected data points to generate the resulting model relating pressure and vibration (and average rotational speed per cycle, calculated based on the vibration peaks). The model is tested with measurements from two spark ignited engine test benches: a single cylinder engine and a four-cylinder engine. The resulting model has very low computational cost and can provide a very accurate estimation of general shape and magnitude of the pressure trace, but does not reflect strongly cycle by cycle variations. Testing the Normalized Root Mean Square Error (NRMSE), where the best value is 100 % the single cylinder engine scores were 63.52 % and 20.02 % for the points before and after the vibration peak. For the four-cylinder engine those values were: 82.47 % and 28.27 % respectively

Resistencia a fármacos en pacientes en tratamiento antirretroviral, Cali, Colombia, 2008-2010

Introduction: Little has been published in Colombia on HIV drug resistance in patients taking antiretroviral treatment (ART). Currently, the Colombian guidelines do not recommend the use of genotypic antiretroviral resistance tests (GART) for treatment-naive patients or for those experiencing a first therapeutic failure.Objective: To determine the frequency of relevant resistance mutations and the degree of susceptibility/resistance of HIV to antiretroviral drugs (ARVs) in ART-experienced patients.Materials and methods: A non-random sample of 170 ART-experienced HIV patients with virologic failure and who underwent GART was recruited. A study of HIV drug resistance was carried out in two groups of patients: one group that underwent early GART and the other group that received late GART testing.Results: The most frequent type of resistance affected the non-nucleoside class (76%). The late-GART group had higher risk of nucleoside analog and protease inhibitor drug resistance, a higher number of  resistance mutations and more complex mutational profiles than the early-GART group. A high cross resistance level (30%) was found in the nucleoside analog class. The least affected medications were tenofovir and darunavir.Conclusions: Our results suggest that performing GART late is associated with levels of ARV resistance that could restrict the use of an important number of essential ARV in subsequent regimens. There is a need to revise the current recommendations to include GART prior to start of treatment and after the first virologic failure. doi: http://dx.doi.org/10.7705/biomedica.v33i4.1462Introducción. En Colombia se ha publicado poco sobre farmacorresistencia del VIH en pacientes que toman tratamiento antirretroviral (TAR). Las guías de VIH de Colombia de 2006 no recomiendan el uso de los estudios genotípicos de resistencia (EGR) en pacientes nunca expuestos a medicamentos antirretrovirales ni después del primer fracaso terapéutico. Objetivo. Determinar la frecuencia de mutaciones de resistencia y el grado de susceptibilidad/resistencia del VIH a los antirretrovirales en pacientes expuestos a TAR. Materiales y métodos. Se reclutó una muestra no probabilística de 170 pacientes con infección por VIH que tomaban TAR, experimentaban fracaso virológico y que tenían EGR. Se estudió la farmacorresistencia del VIH en dos grupos: EGR temprano vs. EGR tardío.Resultados. El tipo de resistencia más frecuente en pacientes que toman TAR afectó a los inhibidores no nucleosídicos (76%). El grupo tardío tuvo mayor riesgo de resistencia a inhibidores nucleosídicos y a los inhibidores de proteasa, mayor número de mutaciones de resistencia y mayor complejidad de las resistencias que el grupo temprano. También se encontró un alto grado (30%) de resistencia cruzada a los inhibidores nucleosídicos en el grupo tardío. Los medicamentos menos afectados fueron tenofovir y darunavir. Conclusiones. Los resultados de este estudio sugieren que realizar EGR tardíos se asocia a altos niveles de resistencia, lo cual puede restringir el uso de un gran número de ARVs esenciales en regímenes subsiguientes. Es necesario revisar las actuales recomendaciones sobre el uso de EGR en las guías Colombianas de manejo de VIH.   doi: http://dx.doi.org/10.7705/biomedica.v33i4.146

Importancia de las neoplasias en los animales domésticos. Neoplasias diagnosticadas en los centros de epizootiología y diagnóstico veterinario de Guantánamo y Granma, Cuba

Neoplasias affect all animal species and their frequency in veterinary medicine diagnosis has increased in the last few years. They are the cause of huge economic losses and a disagreeable social impact in pets. Data for this research paper were taken from the records of the Centers for Epizootiology Studies and Veterinary Diagnosis in Granma and Guantanamo provinces, Cuba. Canine and bovine animals are the most affected species. Skin carcinoma and Sticker's carcinoma in dogs, and lymphoid neopla- sias and third eyelid carcinoma in bovines are the diseases showing a higher incidence. On the other hand, there is an increasing tendency towards malignant neoplasias in contrast to benign neoplasias.Las neoplasias afectan a todas las especies de animales y en los últimos años han incrementado su frecuencia de presentación en el diagnóstico veterinario. Causan cuantiosas pérdidas económicas y un efecto social desagradable en animales afectivos. La información para este trabajo se obtuvo en los libros de registro de los Centros de Epizootiología y Diagnóstico de las provincias Granma y Guantánamo, Cuba. Las especies más afectadas son la canina y la bovina, con una mayor incidencia de carcinoma de piel y carcinoma de Sticker en la primera y las neoplasias linfoides y carcinoma del tercer párpado en la segunda. Se observa tendencia al incremento del diagnóstico de las neoplasias malignas y estas aparecen más frecuentemente que las benignas

Estimación de la curva de presión en la cámara de combustión de MCI monocilíndricos a partir del análisis de vibraciones

En este artículo se diseña e implementa un sistema para la estimación de la curva de presión en la cámara de combustión en un MCI mediante el análisis de las vibraciones mecánicas provenientes del bloque del motor. Para la generación de la base de datos, se capturaron tres tipos de señales: Vibración en el bloque, velocidad de rotación del cigüeñal y presión en la cámara de combustión (como referencia). Se evaluó el motor trabajando con gasolina a diferentes regímenes de velocidad (1100, 1500, 2000 y 2500 rpm) en condiciones normales. Las señales de vibración fueron caracterizadas mediante el uso de transformadas rápidas de Fourier (FFT) y transformadas en tiempo corto de Fourier (STFT). Para estimar la curva de presión, se hizo uso de regresión rígida con Kernel utilizando una función gaussiana. Se valida la estimación de la curva de presión comparándola con la curva obtenida por medio del sensor de presión. Se utilizó una validación cruzada para medir la precisión del sistema. Los resultados demostraron que la estimación de la curva de presión en la cámara de combustión es apropiada, cuando el MCI trabaja a diferentes velocidades en condiciones normales de operación.Eje: Eficiencia energética.Facultad de Ingenierí

Estimación de la curva de presión en la cámara de combustión de MCI monocilíndricos a partir del análisis de vibraciones

En este artículo se diseña e implementa un sistema para la estimación de la curva de presión en la cámara de combustión en un MCI mediante el análisis de las vibraciones mecánicas provenientes del bloque del motor. Para la generación de la base de datos, se capturaron tres tipos de señales: Vibración en el bloque, velocidad de rotación del cigüeñal y presión en la cámara de combustión (como referencia). Se evaluó el motor trabajando con gasolina a diferentes regímenes de velocidad (1100, 1500, 2000 y 2500 rpm) en condiciones normales. Las señales de vibración fueron caracterizadas mediante el uso de transformadas rápidas de Fourier (FFT) y transformadas en tiempo corto de Fourier (STFT). Para estimar la curva de presión, se hizo uso de regresión rígida con Kernel utilizando una función gaussiana. Se valida la estimación de la curva de presión comparándola con la curva obtenida por medio del sensor de presión. Se utilizó una validación cruzada para medir la precisión del sistema. Los resultados demostraron que la estimación de la curva de presión en la cámara de combustión es apropiada, cuando el MCI trabaja a diferentes velocidades en condiciones normales de operación.Eje: Eficiencia energética.Facultad de Ingenierí

Estimación de la curva de presión en la cámara de combustión de MCI monocilíndricos a partir del análisis de vibraciones

En este artículo se diseña e implementa un sistema para la estimación de la curva de presión en la cámara de combustión en un MCI mediante el análisis de las vibraciones mecánicas provenientes del bloque del motor. Para la generación de la base de datos, se capturaron tres tipos de señales: Vibración en el bloque, velocidad de rotación del cigüeñal y presión en la cámara de combustión (como referencia). Se evaluó el motor trabajando con gasolina a diferentes regímenes de velocidad (1100, 1500, 2000 y 2500 rpm) en condiciones normales. Las señales de vibración fueron caracterizadas mediante el uso de transformadas rápidas de Fourier (FFT) y transformadas en tiempo corto de Fourier (STFT). Para estimar la curva de presión, se hizo uso de regresión rígida con Kernel utilizando una función gaussiana. Se valida la estimación de la curva de presión comparándola con la curva obtenida por medio del sensor de presión. Se utilizó una validación cruzada para medir la precisión del sistema. Los resultados demostraron que la estimación de la curva de presión en la cámara de combustión es apropiada, cuando el MCI trabaja a diferentes velocidades en condiciones normales de operación.Eje: Eficiencia energética.Facultad de Ingenierí

Correlates of tobacco cessation counseling among Hispanic physicians in the US: a cross-sectional survey study.

BACKGROUND: Physician advice is an important motivator for attempting to stop smoking. However, physicians\u27 lack of intervention with smokers has only modestly improved in the last decade. Although the literature includes extensive research in the area of the smoking intervention practices of clinicians, few studies have focused on Hispanic physicians. The purpose of this study was to explore the correlates of tobacco cessation counseling practices among Hispanic physicians in the US. METHODS: Data were collected through a validated survey instrument among a cross-sectional sample of self-reported Hispanic physicians practicing in New Mexico, and who were members of the New Mexico Hispanic Medical Society in the year 2001. Domains of interest included counseling practices, self-efficacy, attitudes/responsibility, and knowledge/skills. Returned surveys were analyzed to obtain frequencies and descriptive statistics for each survey item. Other analyses included: bivariate Pearson\u27s correlation, factorial ANOVAs, and multiple linear regressions. RESULTS: Respondents (n = 45) reported a low level of compliance with tobacco control guidelines and recommendations. Results indicate that physicians\u27 familiarity with standard cessation protocols has a significant effect on their tobacco-related practices (r = .35, variance shared = 12%). Self-efficacy and gender were both significantly correlated to tobacco related practices (r = .42, variance shared = 17%). A significant correlation was also found between self-efficacy and knowledge/skills (r = .60, variance shared = 36%). Attitudes/responsibility was not significantly correlated with any of the other measures. CONCLUSION: More resources should be dedicated to training Hispanic physicians in tobacco intervention. Training may facilitate practice by increasing knowledge, developing skills and, ultimately, enhancing feelings of self-efficacy

Complement component C4 structural variation and quantitative traits contribute to sex-biased vulnerability in systemic sclerosis

Altres ajuts: Fondo Europeo de Desarrollo Regional (FEDER), "A way of making Europe".Copy number (CN) polymorphisms of complement C4 play distinct roles in many conditions, including immune-mediated diseases. We investigated the association of C4 CN with systemic sclerosis (SSc) risk. Imputed total C4, C4A, C4B, and HERV-K CN were analyzed in 26,633 individuals and validated in an independent cohort. Our results showed that higher C4 CN confers protection to SSc, and deviations from CN parity of C4A and C4B augmented risk. The protection contributed per copy of C4A and C4B differed by sex. Stronger protection was afforded by C4A in men and by C4B in women. C4 CN correlated well with its gene expression and serum protein levels, and less C4 was detected for both in SSc patients. Conditioned analysis suggests that C4 genetics strongly contributes to the SSc association within the major histocompatibility complex locus and highlights classical alleles and amino acid variants of HLA-DRB1 and HLA-DPB1 as C4-independent signals