127 research outputs found

    Facial Geometry Identification through Fuzzy Patterns with RGBD Sensor

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    Automatic human facial recognition is an important and complicated task; it is necessary to design algorithms capable of recognizing the constant patterns in the face and to use computing resources efficiently. In this paper we present a novel algorithm to recognize the human face in real time; the systems input is the depth and color data from the Microsoft KinectTM device. The algorithm recognizes patterns/shapes on the point cloud topography. The template of the face is based in facial geometry; the forensic theory classifies the human face with respect to constant patterns: cephalometric points, lines, and areas of the face. The topography, relative position, and symmetry are directly related to the craniometric points. The similarity between a point cloud cluster and a pattern description is measured by a fuzzy pattern theory algorithm. The face identification is composed by two phases: the first phase calculates the face pattern hypothesis of the facial points, configures each point shape, the related location in the areas, and lines of the face. Then, in the second phase, the algorithm performs a search on these face point configurations

    Time-frequency analysis based on minimum-norm spectral estimation to detect induction motor faults

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    Producción CientíficaIn this work, a new time-frequency tool based on minimum-norm spectral estimation is introduced for multiple fault detection in induction motors. Several diagnostic techniques are available to identify certain faults in induction machines; however, they generally give acceptable results only for machines operating under stationary conditions. Induction motors rarely operate under stationary conditions as they are constantly affected by load oscillations, speed waves, unbalanced voltages, and other external conditions. To overcome this issue, different time-frequency analysis techniques have been proposed for fault detection in induction motors under non-stationary regimes. However, most of them have low-resolution, low-accuracy or both. The proposed method employs the minimum-norm spectral estimation to provide high frequency resolution and accuracy in the time-frequency domain. This technique exploits the advantages of non-stationary conditions, where mechanical and electrical stresses in the machine are higher than in stationary conditions, improving the detectability of fault components. Numerical simulation and experimental results are provided to validate the effectiveness of the method in starting current analysis of induction motors.Consejo Nacional de Ciencia y Tecnología (Proyecto 487058)Universidad de Guanajuato (Proyecto 248495/2019

    EEMD-MUSIC-Based Analysis for Natural Frequencies Identification of Structures Using Artificial and Natural Excitations

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    This paper presents a new EEMD-MUSIC- (ensemble empirical mode decomposition-multiple signal classification-) based methodology to identify modal frequencies in structures ranging from free and ambient vibration signals produced by artificial and natural excitations and also considering several factors as nonstationary effects, close modal frequencies, and noisy environments, which are common situations where several techniques reported in literature fail. The EEMD and MUSIC methods are used to decompose the vibration signal into a set of IMFs (intrinsic mode functions) and to identify the natural frequencies of a structure, respectively. The effectiveness of the proposed methodology has been validated and tested with synthetic signals and under real operating conditions. The experiments are focused on extracting the natural frequencies of a truss-type scaled structure and of a bridge used for both highway traffic and pedestrians. Results show the proposed methodology as a suitable solution for natural frequencies identification of structures from free and ambient vibration signals

    Threatened abortion and gestational diabetes cases in Mexican pregnant women does not change with the FTO rs9939609 presence

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    The Obesity-associated fat mass (FTO) gene has been associated to a higher risk of obstetrical complications. The aim of this prospective, cross-sectional and comparative study was to determine if there are clinical or laboratorial differences in pregnant women with the presence/absence of FTO rs9939609 focused on threatened abortion. Pregnant women between 18 to 35 years of age were invited to participate. In all cases, it was obtained the sociodemographic information, anthropometry, clinical laboratories for obstetrical routine check-up, FTO rs9939609 positive expression, and the homeostasis model assessment (HOMA) and the quantitative insulin sensitivity check index (QUICKI) indexes were also calculated. Comparisons of this type of variables between both groups were performed through Student´s T-test. Chi-Square Tests were used to contrast the GDM and threatened miscarriages percentages of cases between both groups. Pearson correlation was performed among the quantitative variables of all the study population. 57 women positive and 52 negative for the FTO rs9939609 presence were included in the study with a Gestational Diabetes Mellitus prevalence of 19.3%. When contrasting the variables by the presence/absence of FTO rs9939609 the p-values were far from being significant. As such, Chi-Square Tests did not show significant statistical difference neither for GDM nor for threatened miscarriage between both groups. Based on these results, the FTO rs9939609 presence did not reflect difference either in GDM or in threatened miscarriage. It was demonstrated in parallel, the utility of the QUICKI index in the metabolic evaluation during pregnancy. In conclusion, in Mexican women, pregnancy evolution and possible appearance of complications is not so determined by the FTO rs9939609 presence but by the overweight with which this physiological state is faced

    Hand Hygiene Teaching Strategies among Nursing Staff: A Systematic Review

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    Background: Patient safety is a priority of any healthcare system, and one of the most effective measures is hand hygiene. For this, it is important that health staff have correct adherence and perform the technique properly. Otherwise, the incidence of nosocomial infections can increase, with consequent complications. The aim here was to analyze hand hygiene training and the effectiveness of different methods and educational strategies among nurses and whether they maintained correct adherence over time. Results: n = 17 clinical trials were included, with a total of 5747 nurses and nursing students. Strategies such as reminder sounds, practical simulations, videos, and audiovisual media improved handwashing compliance. Adherence overtime increased by up to 60%. The greatest effectiveness was related to the use of povidone–iodine, which reduced colony formation compared Hand hygiene teaching strategies among nursing staff: a systematic review to soap. Conclusions: The strategies that go beyond teaching techniques such as lectures may be more effective at increasing hand hygiene compliance. Combined approaches to learning/instruction improve user satisfaction by enabling self-management, flexibility, and repetition

    Influence of dietary fiber upon in vitro microbial cecal fermentation in mexican hairless and mexican cuino pigs

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    The objective of the present study was to evaluate and compare the in vitro cecal fermentation (by the gas production technique), in Mexican hairless pig (MHP) and Mexican cuino pig (MCP), adding cellulose or starch as substrates (0, 100, 200, 300 and 400 mg/g DM). 12 pigs were slaughtered (BW= 104±0.5 kg), six of each genotype were collected from the cecal contents and there was a pool for every two pigs in each genotype, and thereafter, for each substrate (cellulose or starch) in its different concentration, three flasks were incubated with inoculum for each pool and made three series of incubation. The experimental design use the effect of genotype, substrate and concentration of the substrate added on the variables of in vitro fermentation. The averages of the data were compared by Tukey's method. In vitro gas production was higher (P<0.05) (mL/g DM) for MHP (206.8) vs MCP (180.2). The degradation fractional rate rhythm (b, 0.094 and c, -0.0127) and lag time (1.79) of the MHP was higher than MCP (b, 0.074; c -0.102) and lag time (1.26); with the addition of carbohydrates as substrates, in vitro gas production of potato starch was higher (P<0.05) than cellulose (238.3 vs 148.7 mL/g DM); the fractions b, c and lag time, there were differences (P<0.05) between substrates. The increasing addition of cellulose or starch had a lineal effect (P<0.05) with the gas production, level cero mg (133.46) to 400 mg of substrate (263.16 mL/g DM). MHP had a higher cecal fermentation than MCP, being higher the gas production at 9 and 12 h, there was higher gas production (cecal fermentation) when added starch as substrate

    Fault detection in VSD-fed induction motors through Park’s impedance and fuzzy systems

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    Industrial applications that require speed control have been increasing in recent years and the use of variable speed drives (VSD) for feeding induction motors (IM) is more common. Therefore, methodologies for detecting faults on VSD-fed IM are needed with the aim of minimize cost in maintenance and reduce the power consumption. In this work a methodology for fault diagnosis is proposed through spectral patterns obtained from the Park’s impedance. Broken rotor bar, unbalanced mass, and misalignment conditions are investigated and a fuzzy-logic diagnosis system is proposed for asserting the VSD-fed IM condition. Results show high effectiveness in detection of the investigated fault conditions through the proposed methodology, which has been validated with experimental tests.Index terms: fault detection, impedance analysis, induction motors, park transform, variable speed drives

    Cociente plaquetas/bazo para el diagnóstico de várices esofágicas y riesgo de sangrado en pacientes con insuficiencia hepática: Platelet / spleen ratio for the diagnosis of esophageal varices and the risk of bleeding in patients with liver failure

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    Introduction:&nbsp;Upper gastrointestinal bleeding of variceal origin has a high mortality. The platelet count/spleen major diameter ratio may be a useful noninvasive parameter to predict esophageal variceal bleeding in cirrhotic patients.&nbsp;Objective: to determine the sensitivity and specificity of the platelet count/spleen diameter ratio for the diagnosis of esophageal varices with risk of bleeding in patients with hepatic insufficiency.&nbsp;Material and Methods: Process study, performed in a Second Level Medical Facility, in patients with liver failure who underwent ultrasound, blood cytometry, liver function tests and endoscopy. Sensitivity and specificity of the platelet/spleen ratio were assessed in patients with esophageal variceal and bleeding risk.&nbsp;Results: There were 70 patients: 28 women, 42 men; main cause of liver failure in men was ethylism in 31 patients and hepatitis C virus in 20 women.&nbsp;The spleen-platelet ratio has a sensitivity of 90%, specificity 83%, false positives 16%, false negatives 9%, positive predictive value 94%, negative predictive value 75%, prevalence of 74% and diagnostic accuracy of 88% to diagnose esophageal varices with risk of bleeding.&nbsp;Conclusion: Platelet/spleen ratio is a useful, non-invasive study to diagnose esophageal varices with bleeding risk, in hospitals where endoscopy is not available.Introducción. El sangrado de tubo digestivo alto de origen variceal tiene una mortalidad alta. El cociente número de plaquetas/diámetro mayor del bazo puede ser un parámetro no invasivo útil para predecir el sangrado por várices esofágicas en pacientes cirróticos.&nbsp;Objetivo: Determinar la sensibilidad y especificidad del cociente número de plaquetas/diámetro mayor del bazo, para el diagnóstico de várices esofágicas con riesgo de sangrado en pacientes con insuficiencia hepática.&nbsp;Material Y Métodos:&nbsp;Estudio de proceso, realizado en un hospital de segundo nivel de atención médica, en pacientes con insuficiencia hepática a quienes se les realizó ultrasonido, citometría hemática, pruebas de función hepática y endoscopia. Se valoró sensibilidad y especificidad del cociente plaquetas/bazo para el diagnóstico de várices esofágicas con riesgo de sangrado.&nbsp;Resultados:&nbsp;Fueron 70 pacientes: 28 mujeres, 42 hombres; causa principal de insuficiencia hepática en hombres fue etilismo en 31 pacientes, virus de la hepatitis C en 20 mujeres.&nbsp;El cociente bazo-plaquetas tiene una sensibilidad de 90%, especificidad 83%, falsos positivos 16%, falsos negativos 9%, valor predictivo positivo 94%, valor predictivo negativo 75 %, prevalencia del 74% y una certeza diagnóstica del 88% para diagnosticar várices esofágicas con riesgo de sangrado.&nbsp;Conclusión:&nbsp;El cociente plaquetas/bazo es un estudio útil y no invasivo para diagnosticar várices esofágicas con&nbsp;riesgo de sangrado, en hospitales donde no se cuenta con endoscopía

    Day-night variation of acute myocardial infarction in obstructive sleep apnea.

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    OBJECTIVES: This study sought to evaluate the day-night variation of acute myocardial infarction (MI) in patients with obstructive sleep apnea (OSA). BACKGROUND: Obstructive sleep apnea has a high prevalence and is characterized by acute nocturnal hemodynamic and neurohormonal abnormalities that may increase the risk of MI during the night. METHODS: We prospectively studied 92 patients with MI for which the time of onset of chest pain was clearly identified. The presence of OSA was determined by overnight polysomnography. RESULTS: For patients with and without OSA, we compared the frequency of MI during different intervals of the day based on the onset time of chest pain. The groups had similar prevalence of comorbidities. Myocardial infarction occurred between 12 am and 6 am in 32% of OSA patients and 7% of non-OSA patients (p = 0.01). The odds of having OSA in those patients whose MI occurred between 12 am and 6 am was 6-fold higher than in the remaining 18 h of the day (95% confidence interval: 1.3 to 27.3, p = 0.01). Of all patients having an MI between 12 am and 6 am, 91% had OSA. CONCLUSIONS: The diurnal variation in the onset of MI in OSA patients is strikingly different from the diurnal variation in non-OSA patients. Patients with nocturnal onset of MI have a high likelihood of having OSA. These findings suggest that OSA may be a trigger for MI. Patients having nocturnal onset of MI should be evaluated for OSA, and future research should address the effects of OSA therapy for prevention of nocturnal cardiac events
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