Smartphone addiction and life satisfaction: mediating effect of negative emotions / Adicción a teléfonos inteligentes y satisfacción con la vida: efecto mediador de las emociones negativas

Background: Smartphone users have increased worldwide, due to their multifunctionality and accessibility. Objective: To determine the mediating effect of negative emotions between life satisfaction and smartphone addiction in college students. Method: A structural equation explanatory model was proposed in which each negative emotion (depression, anxiety, and stress) has a mediating role between life satisfaction and cell phone addiction. To this end, 1109 university students from Metropolitan Lima were selected and administered the DASS 21, SABAS, SWLS. Result: A partial effect of each mediating model was found, in addition to Satisfaction with life achieved a direct effect on cell phone addiction; at the same time the mediating variables achieved a significant direct effect on addictive behavior. Conclusion: Negative emotions have a mediating role in explaining smartphone addiction.

Introducción: Los usuarios de teléfonos inteligentes se han incrementado a nivel mundial, debido a su multifuncionalidad y accesibilidad. Objetivo: Determinar el efecto mediador de las emociones negativas entre la satisfacción con la vida y la adicción a los teléfonos inteligentes en universitarios. Método: Se planteó un modelo explicativo de ecuaciones estructurales en el cual cada emoción negativa (depresión, ansiedad y estrés) tienen un rol mediador entre la satisfacción con la vida y la adicción a los celulares. Con tal fin, se seleccionaron 1109 universitarios de Lima Metropolitana a los cuales se les aplicaron el DASS 21, SABAS, SWLS. Resultados: Se encontró un efecto parcial de cada modelo mediador, además la Satisfacción con la vida logró un efecto directo sobre la adicción a los teléfonos celulares; al mismo tiempo las variables mediadoras consiguieron un efecto directo significativo sobre la conducta adictiva. Conclusión: las emociones negativas tienen un rol mediador en la explicación de la adicción a los teléfonos inteligentes.

Analyzing the characteristics and influencing factors of high frequency hearing loss among noise-exposed workers in an urban rail transit enterprise / 中国职业医学

{L-End}Objective To analyze the characteristics of hearing loss and the influencing factors of high-frequency hearing loss (HFHL) among noise-exposed workers in an urban rail transit enterprise over five consecutive years. {L-End}Methods A total of 1 268 noise-exposed workers, who exposed to the average noise intensity of <85.0 dB(A), in an urban rail transit enterprise was selected as the research subjects using a judgment sampling method. The pure-tone audiometry results from 2019 to 2023 were collected to analyze the result of hearing loss. The influencing factors of HFHL (average hearing threshold ≥40.0 dB at high frequencies in both ears) were analyzed using the generalized estimating equations (GEE). {L-End}Results The detection rates of threshold elevations at frequencies of 0.5-6.0 kHz increased with increasing frequency from 2019 to 2023 (all P<0.01), with the highest detection rate at 6.0 kHz. The detection rate of speech frequency hearing loss (hearing threshold weighted value≥26.0 dB in the better ear) was 0.1%, 0.0%, 0.4%, 0.2%, and 0.2%, respectively. The detection rate of HFHL from 2019 to 2023 was 2.4%, 2.8%, 2.8%, 2.1%, and 2.8%, respectively. The GEE analysis results showed that the risk of HFHL of the workers in 2022 and 2023 was lower than that in 2019 (all P<0.01), with the odds ratios and 95% confidence intervals ［OR (95%CI)］ of 0.57 (0.41-0.81) and 0.65 (0.48-0.87), respectively. The risk of HFHL was higher among vehicle maintenance worker than train drivers (P<0.05), with OR (95%CI) of 2.37 (1.18-4.77). The risk of HFHL increased with age and length of service among the workers (all P<0.05), with the OR (95%CI) of 2.05 (1.22-3.46) and 1.69 (1.12-2.54), respectively. No interaction was found between type of job and age, type of job and length of service, or age and length of service in the risk of HFHL among the research subjects(all P<0.05). {L-End}Conclusion Noise exposure below the national occupational exposure limits can lead to hearing loss in noise-exposed workers of urban rail transit enterprises, possibly affecting the hearing threshold at 6.0 kHz first. The influencing factors for HFHL in workers of rail transit are age, length of service, and type of job. There is a dose-effect relationship with age and length of service.

Codependencia laboral: análisis factorial confirmatorio

El objetivo de esta investigación es validar un instrumento para medir la codependencia laboral. El método implementado fue un enfoque cuantitativo, de diseño no experimental transeccional, utilizando un análisis factorial confirmatorio basado en ecuaciones estructurales. Los resultados mostraron que el modelo presentó un ajuste adecuado NC =1.86; ρ=0.000; NFI=.979; IFI=.990; CFI=.990; MFI=.925 Y RMSEA=.68. Se concluye que los factores relacionados con la falta de confianza y los comportamientos abusivos son los elementos que describen la codependencia en el ámbito laboral.

The objective of this research is to validate an instrument to measure labor co-dependency, using a quantitative approach of non-experimental trans-sectional design, via a Confirmatory Factor Analysis based on structural equations. Results showed that the model presented an adequate adjustment NC = 1.86; p = 0.000; NFI = .979; IFI = .990; CFI = .990; MFI = .925, and RMSEA = .68. It is concluded that the factors related to lack of trust and abusive behaviors are the elements that describe co-dependency in the workplace.

A Study On Linear Equations, Solutions Of Linear Equations

This Paper is the study of a system of linear equations in n unknowns and finding solution by various methods, Gauss elimination method, Gauss Jordan method, Gauss Seidel method. A System of Linear Equations is two or more linear equations together. The solution to a system of linear equations is the point at which the lines representing the linear equations intersect. When there is no solution then the system of linear equations is referred as "inconsistent”. If there is one or infinitely many solutions then the system of linear equations is referred as “consistent". Many problems in Engineering and applied sciences require the solution of System of equations. The system of linear equations used to solve age problems, to calculate speed, distance and time of a moving object. It is also used to calculate money and percentage problems,Work, time and wages problems. Problems on force and pressure can also be solved.

Exploratory multigroup structural equation modeling approach to analyzing H. pylori infection, serological pepsinogen levels, and life style factors in an elderly population in Costa Rica / Enfoque exploratorio del modelo de ecuaciones estructurales multigrupo para el análisis de la infección con H. pylori, niveles de pepsinógenos séricos y factores asociados a estilo de vida en una población de adultos mayores en Costa Rica

Abstract The aim of this work is to describe and analyze the association of PGI/PGII ratio (indicator of gastric atrophy) with H. pylori-CagA and life style factors such as caloric intake, obesity, and harmful habits amongst H. pylori-positive elderly people infected in Costa Rica using an exploratory multigroup structural equations model (SEM). Using a sample of 1748 H. pylori-positive elderly people from CRELES first wave study, a SEM was employed analyze if the relationships between PGI/PGII ratio with levels of H. pylori-CagA, caloric intake, obesity, and harmful habits, differs by sex, age and risk areas subgroups. The proposed SEMs exhibited a good fit in males (RMSEA = 0.039), females (RMSEA = 0.000), low-risk area (RMSEA = 0.038), middle-risk area (RMSEA = 0.042), individuals under 80 years (RMSEA = 0.038) and individuals aged 80 and over (RMSEA = 0.042), while an acceptable fit was observed for the high-risk area (RMSEA = 0.061). Fitted SEMs showed that CagA predicted PG-ratio as expected, with effects increasing with the risk area, but similar between sex and age groups. All indicators measuring obesity (BMI, arms, and waist) showed significant standardized coefficients, with similar effects between sex, age and risk area groups. No other significant effects or differences between groups were identified. We propose a good-fitted SEM model for the possible relationships between CagA and PG ratio and the geographical risk area level for elderly people. No differences were observed on measured parameters between male and female population, or between under 80 years and older individuals.

Resumen El objetivo de este trabajo es describir y analizar la asociación entre PGI/PGII (indicador de atrofia gástrica con H. pylori-CagA y factores asociados a estilo de vida como ingesta calórica, obesidad y hábitos nocivos entre adultos mayores positivos por H. pylori en Costa Rica utilizando modelos de ecuaciones estructurales multigrupo (SEM). Con una muestra de 1748 adultos mayores del estudio CRELES, se utilizó un SEM para analizar las relaciones entre PGI/PGII, CagA, ingesta calórica, obesidad y hábitos nocivos difieren por sexo, edad y áreas de riesgo. Los SEMs propuestos exhibieron un buen ajuste en hombres (RMSEA = 0.039), mujeres (RMSEA = 0.000), área de bajo riesgo (RMSEA = 0.038), áreas de riesgo medio (RMSEA = 0.042), individuos menores de 80 años (RMSEA = 0.038) e individuos de 80 años o más (RMSEA = 0.042), mientras que hubo un ajuste aceptable en áreas de alto riesgo (RMSEA = 0.061). Los SEMs ajustados mostraron que CagA predice la relación PGI/II en la dirección esperada con efectos proporcionales al área de riesgo, pero no por sexo y edad. Todos los indicadores medibles de obesidad (IMC, brazos y cintura) mostraron coeficientes estandarizados significativos con efectos similares entre los grupos por sexo, edad y área de riesgo. No se encontraron otros efectos o diferencias significativas. Proponemos un modelo SEM bien ajustado para las posibles relaciones entre CagA y PGI/II y el nivel de riesgo del área geográfica en adultos mayores. No se encontraron diferencias en las variables analizadas entre hombres y mujeres ni entre los grupos de edad.

Validez de la Estructura Interna del Utrecht Work Engagement Scale (UWES) en trabajadores peruanos / Internal structure validity of Utrecht Work Engagement Scale (UWES) in Peruvian workers

Resumen El Utrecht Work Engagement Scale (UWES), medida de engagement laboral, ha tenido controversias respecto a la interpretación de su dimensionalidad, es decir, si sus puntajes pueden ser unidimensionales, multidimensionales o de dos niveles (unidimensional y multidimensional). El presente estudio tuvo por objetivo examinar la estructura interna (dimensionalidad, invarianza de medición y confiabilidad) del UWES (dos versiones: larga y breve) en una muestra de 636 trabajadores peruanos. Se aplicó el modelamiento de ecuaciones estructurales para la evaluación de tres modelos de dimensionalidad: un solo factor (unidimensionalidad), tres factores relacionados (multidimensionalidad) y bifactor (dos niveles de interpretación: factor general y factores específicos). Los resultados indican que, luego de aplicar el modelamiento bifactor, la varianza común obtenida de un factor general es más fuerte que la interpretación de tres dimensiones. Este resultado se repitió en ambas versiones del UWES (larga y breve). La invarianza de medición fue satisfactoria en el nivel configuracional, métrica y escalar (en ambas versiones). Con respecto a la consistencia interna, se obtuvieron coeficientes satisfactorios (mayores a .70). Se concluye que el modelo de tres dimensiones del UWES para obtener los puntajes debe ser reemplazado por un modelo unidimensional, representado con un puntaje total. Se discuten las implicaciones teóricas y prácticas.

Abstract The Utrecht Work Engagement Scale (UWES), a measure of work engagement, has had controversies regarding the interpretation of its dimensionality, that is, whether its scores can be one-dimensional, multidimensional or two-level (one-dimensional and multidimensional). The dimensionality of the UWES has been questioned mainly due to the high covariation between its components, an aspect consistently verified in the observed scores and latent variables (De Bruin y Henn 2013), even by the same authors (Schaufeli et al., 2006). This has two implications, one operational and one conceptual. In the operational context, the calculation of scores is also influenced by the statistical differentiation of the factors found in the factor analyzes. This means that if one or more factors are retained and justified, this also determines the same number of observed scores that can be calculated and interpreted. On the other hand, the conceptual implication is that the comprehensive framework of a three-dimensional psychological phenomenon differs from the one-dimensional. For example, the differentiation between dimensions generates the possibility of different trends between dimensions (e. g., one of three is high and the other low) and in this case, the concept of engagement becomes very generic and ambiguous to name and understand the different possibilities. Specific combination of its dimensions or jeopardizes its content validity, implying the need for other more specific concepts, which although related to engagement, can be independent. The objective of the present study was to examine the internal structure (dimensionality, measurement invariance and reliability) of the UWES (two versions: long and short) in a sample of 636 Peruvian workers. Structural equation modeling was applied to evaluate three dimensionality models: a single factor (one-dimensionality), three related factors (multidimensionality) and bifactor (two levels of interpretation: general factor and specific factors). The results indicate that, after applying bifactor modeling, the common variance obtained from a general factor is stronger than the three-dimensional interpretation. This result was repeated in both versions of the UWES (long and short). The measurement invariance was satisfactory at the configurational, metric and scalar levels (in both versions). Regarding internal consistency, satisfactory coefficients (greater than .70) were obtained. Three issues emerge from this study that modify the original theoretical interpretation of the UWES (which consists of using three related factors). The first is the existence of a general factor underlying the items, and which is statistically substantial as a source of variance of the items, independent of specific factors. In this general factor, the items generally contribute to their variance, except for two items whose discriminative capacity is moderately low (11 and 13, both of the specific factor Absorption). The main element of this general factor is the Dedication factor, whose items completely represented this general factor. Second, the differentiation of two specific factors corresponding to Vigor and Absorption does not appear to be psychometrically sufficient to describe nested constructs within the engagement construct, and therefore its independent interpretation of the general factor could be questioned. However, a contrary argument is that both factors show different amount of specific variance, although low compared to the general factor; for example, Absorption shows more divergent validity compared to Vigor, while the latter contains more common variance (general factor). Third, Dedication was completely absorbed by the general factor, and is only relevant insofar as its items are completely related to the general factor. Therefore, this component lost statistical autonomy and, consequently, very poor conceptual differentiation. It is concluded that the UWES - three-dimensional model to obtain the scores must be replaced by a one-dimensional model, represented with a total score. Implications are future research are discussed.

Local Atmospheric Electric Circuit Model Using Electrostatic Pickups on a 375kV Transmission Line

Abstract: The global atmospheric electric circuit is based on a model of electrical connection between the earth and the ionosphere (waveguide), capable of representing the flow of electric current in this waveguide. In the proposed model, a storm acts as a generator, allowing the ionosphere to maintain its highest electrical potential (approximately 300kV) in relation to Earth. When a storm forms, the bottom of the cloud becomes negatively charged. This study is focused on modeling this specific part of the global atmospheric electric circuit, which is renamed local atmospheric electric circuit. In the methodology, we use an RLC circuit to calculate the effects of electrified clouds in a 375kV transmission line considering an electrical coupling between them (an RLC circuit is an electrical circuit consisting of a resistor (R), an inductor (L), and to capacitor (C). The mathematical formulation was developed using transmission line theory considering a connection with the top of the storm cloud. Then, a model simulation using GNU Octave was performed, and the results demonstrated how this coupling affects voltage drop and phase shift in a 375kV transmission line. Thus, a local atmospheric electric circuit model, considering the particularities of the environment immersed in a real transmission line model, configures an important model in the perspective of project management of electric energy transmission networks.

Estudio morfométrico y ecuaciones de predicción del peso corporal en llamas (Lama glama) Ch'aku y Q'ara / Morphometric study and body weight prediction equations in llamas (Lama glama) Ch'aku and Q'ara

RESUMEN: En el estudio se utilizó una población de 180 llamas de ambos sexos (machos y hembras) clasificados por edades (dientes de leche; dos dientes y cuatro dientes). Se registraron datos del peso corporal y las siguientes medidas morfométricas: En la cabeza: Longitud de la cabeza (LC); ancho de cabeza (ACa) y longitud de oreja (LO). En el cuello: Longitud del cuello (LCU); Perímetro de cuello anterior (PCuA) y perímetro de cuello posterior (PCuP). En el tronco y extremidades: Altura a la cruz (AC); altura de la grupa (AGRU), diámetro dorso esternal (DDE), perímetro torácico (PT), longitud del cuerpo (LOCU), longitud de la cruz a la grupa (LCG), longitud de grupa (LGRU), perímetro de caña anterior (PCA); perímetro de caña posterior (PCP). Los datos fueron procesados utilizando el software estadístico R. Concluyendo que los rasgos de conformación en llamas (Lama glama) Ch'aku y Q'ara están influenciados por la edad, sexo y raza. Los modelos de regresión simple y múltiple para la predicción del peso corporal fueron significativos.

SUMMARY: The study used a population of 180 llamas of both sexes (males and females) classified by age (milk teeth; two teeth and four teeth). Body weight data and the following morphometric measurements were recorded: Head: Head length (CL); head width (ACa) and ear length (LO). On the neck: Neck length (LCU); anterior neck circumference (PCuA) and posterior neck circumference (PCuP). On the trunk and limbs: Height at withers (AC); height at rump (AGRU), sternal dorsal diameter (DDE), thoracic perimeter (PT), body length (LOCU), length from withers to rump (LCG), rump length (LGRU), anterior canine perimeter (PCA); posterior canine perimeter (PCP). The data were processed using R statistical software. It was concluded that conformation traits in Ch'aku and Q'ara llamas (Lama glama) are influenced by age, sex and breed. Simple and multiple regression models for body weight prediction were significant.

Predictive equations for ventilatory muscle strength in the Brazilian population: a systematic review / Equações preditivas da força muscular ventilatória na população brasileira: uma revisão sistemática / Ecuaciones predictivas de la fuerza muscular respiratoria en la población brasileña: una revisión sistemática

ABSTRACT Maximal inspiratory and expiratory pressures (MIP and MEP) assess the strength index of the respiratory muscles. These measures are relevant to assess respiratory muscle strength and for clinical monitoring. This study evaluates papers that suggest predictive equations of MIP and MEP for the Brazilian population. We included studies that established prediction equations for MIP and MEP for the healthy Brazilian population, aged from 4 to 90 years old, both men and women and that had the maximum respiratory pressures measured in a sitting position. A search was carried out in March 2020 on MEDLINE, LILACS, Cochrane, SciELO, CINAHL, Web of Science, and SCOPUS databases, without date or language filters. The descriptors used were "muscle strength," "equations," "predictive respiratory muscles" and their respective synonyms. Out of the 3,920 studies found in databases, 963 were duplicates, 2,779 were excluded, 178 had their full texts analyzed, and only 9 met the inclusion criteria. The predictive equations of ventilatory muscle strength analyzed in this review used age, weight, and stature as variables. However, the studies showed methodological weaknesses, such as lack of cross-validation of the equation, exclusion of outliers, and lack of familiarization of MIP and MEP.

RESUMO As pressões respiratórias máximas (PImáx e PEmáx) avaliam o índice de força dos músculos respiratórios. Essas medidas são relevantes para a avaliação da força muscular respiratória e para o monitoramento clínico. O objetivo deste estudo foi avaliar os artigos que sugerem equações preditivas de PImáx e PEmáx para a população brasileira. Foram incluídos estudos que estabeleceram equações de predição para PImáx e PEmáx da população brasileira saudável, com idades entre 4 e 90 anos e de ambos os sexos, que mediam as pressões respiratórias máximas na posição sentada. Uma pesquisa foi realizada, em março de 2020, nas bases de dados MEDLINE, LILACS, Cochrane, SciELO, CINAHL, Web of Science e SCOPUS, sem filtros de tempo ou idioma. Os descritores utilizados foram "força muscular", "equações" e "músculos respiratórios preditivos", com seus respectivos sinônimos. Dos 3.920 estudos encontrados nas bases de dados, 963 eram duplicados e 2.779 foram excluídos, 178 tiveram seus textos analisados integralmente e apenas 9 atendiam aos critérios de inclusão. As variáveis utilizadas nas equações preditivas de força muscular ventilatória analisadas nesta revisão foram: idade, peso e estatura. No entanto, os estudos mostraram fragilidades metodológicas, como falta de validação cruzada da equação, exclusão de outliers e familiarização do PImáx e PEmáx.

RESUMEN Las presiones inspiratoria y espiratoria máximas (PImáx y PEmáx) evalúan el índice de fuerza muscular respiratoria. Estas medidas son importantes en la evaluación de la fuerza muscular respiratoria y el seguimiento clínico. El objetivo de este estudio fue evaluar los artículos proponen ecuaciones predictivas para PImáx y PEmáx a la población brasileña. Se incluyeron estudios que establecieron ecuaciones predictivas para PImáx y PEmáx a la población brasileña sana de ambos sexos, de entre 4 y 90 años de edad, y que miden las presiones respiratorias máximas en posición sentada. Se realizó, en marzo de 2020, una búsqueda en las bases de datos MEDLINE, LILACS, Cochrane, SciELO, CINAHL, Web of Science y SCOPUS, sin año de publicación específico ni idioma. Los descriptores utilizados fueron "fuerza muscular", "ecuaciones" y "músculos respiratorios predictivos" y sus respectivos sinónimos. De los 3.920 estudios encontrados, 963 eran duplicados y se excluyeron 2.779, así se analizaron 178 textos en su totalidad y solo 9 cumplieron con los criterios de inclusión. Las variables edad, peso y talla fueron las que habían sido utilizadas en las ecuaciones predictivas de fuerza muscular respiratoria analizadas por esta revisión. Sin embargo, los estudios apuntaron limitaciones metodológicas, como falta de validación cruzada de la ecuación, exclusión de outliers y familiaridad de la PImáx y PEmáx.

Correlación entre las ecuaciones para la estimación del filtrado glomerular (MDRD, CKD-EPI,) y la depuración de creatinina en orina de 24 horas en pacientes oncológicos / Correlation between the equations for the estimation of the filtering glomerular (MDRD, CKD-EPI,) and creatinine clearance in 24-hour urine in cancer patients

Demostrar la correlación entre las ecuaciones MDRD, CKD-EPI con la depuración de creatinina de 24 horas en pacientes oncológicos. Estudio transversal realizado en el Instituto Oncológico Nacional Dr Juan Tanca Marengo durante el periodo de tiempo comprendido entre el mes de agosto 2019 a agosto de 2020. Al evaluar las distintas variable MDRD obtuvo un valor promedio de 44,81 ml/min/m2 con un intervalo de 41,07 ­ 48,55 ml/min/m2 , la variable CKD-EPI el valor promedio fue 43,59 + 18,09 ml/min/m2 con un intervalo de 40,01 ­ 47,18 ml/min/m2 , para el estándar de referencia depuración de creatinina de 24 horas el promedio fue de 54ml/min/m2 Al evaluar la relación entre los dos estimadores de TFG se encontró que ambos presentan una fiabilidad regular presentando una correlación intraclase de 0,43 (p<0,05) entre los estimadores CKD-EPI y MDRD en relación con la TFG de creatinina de 24horas. Cuando se evaluó pacientes con tumores sólidos y hematológicos, se encontró una mayor correlación intraclase con la escala MDRD-4 0,60 (0,25 ­ 0,82) < 0,05 en tumores hematológicos en comparación con CKD-EPI. En la población general, CKD-EPI es la fórmula recomendada, y se está recomendado con mayor frecuencia en pacientes oncológicos. Nuestro estudio demostró que la ecuación MDRD es la fórmula que mejor se correlaciona con la depuración de creatinina de 24 horas, siendo mejor en el grupo de tumores hematológicos, pero no existe diferencia estadísticamente significativa entre las dos ecuaciones.

To demonstrate the correlation between the MDRD, CKD-EPI equations with the 24-hour creatinine clearance in cancer patients. Cross-sectional study carried out at the National Oncological Institute Dr Juan Tanca Marengo during the period of time between the month of August 2019 to August 2020. When evaluating the different MDRD variables, an average value of 44.81 ml / min / m2 was obtained with an interval of 41.07 ­ 48.55 ml / min / m2, the CKD-EPI variable the average value was 43.59 + 18 , 09 ml / min / m2 with an interval of 40.01 ­ 47.18 ml / min / m2, for the reference standard creatinine clearance of 24 hours the average was 54 ml / min / m2 When evaluating the relationship between the two estimators of GFR, it was found that both present a regular reliability, presenting an intraclass correlation of 0.43 (p <0.05) between the CKD-EPI and MDRD estimators in relation to the 24-hour creatinine GFR. When patients with solid and hematological tumors were evaluated, a higher intraclass correlation was found with the MDRD-4 scale 0.60 (0.25 ­ 0.82) <0.05 in hematological tumors compared to CKD-EPI. In the general population, CKD-EPI is the recommended formulation, and it is more frequently recommended in cancer patients. Our study showed that the MDRD equation is the formula that best correlates with 24-hour creatinine clearance, being better in the group of hematological tumors, but there is no statistically significant difference between the two equations.

¿Qué predice la realización de dietas? Dietas, grasa corporal e insatisfacción corporal en un modelo de ecuaciones estructurales / What does dieting predict? Diets, body fat and body dissatisfaction in a structural equations

Resumen Introducción: Actualmente existe una tendencia a la realización de dietas no saludables, siendo particularmente vulnerable el estudiantado universitario debido a la asunción de responsabilidades en la adquisición de hábitos alimentarios. Objetivos: El propósito de esta investigación ha sido verificar el ajuste de un modelo teórico, con ecuaciones estructurales, para la explicación del número de dietas a través del porcentaje de grasa y la insatisfacción corporal. Las participantes han sido 244 universitarias mexicanas, con una edad media de 19.98 años (DE=1.24). Los instrumentos utilizados han sido el porcentaje de grasa, el número de dietas para perder peso realizadas durante los dos últimos años y el Cuestionario IMAGEN para evaluar los distintos componentes de la insatisfacción corporal. Resultados: Se ha obtenido un ajuste satisfactorio siendo significativas la mayoría de las relaciones hipotetizadas. Se destaca que solo el planteamiento de cambio y el componente comportamental tiene un efecto directo en el número de dietas. También se resalta la capacidad mediadora de los factores de insatisfacción corporal entre las variables porcentaje de grasa y número de dietas. Conclusiones: Teniendo en cuenta el efecto total (efectos directos e indirectos), el componente comportamental, seguido por los componentes malestar emocional, perceptivo y planteamiento de cambio de la insatisfacción corporal, son las variables con mayor poder explicativo sobre el número de dietas. El porcentaje de grasa no muestra efecto directo sobre el número de dietas.

Abstract Introduction: Currently there is a trend towards unhealthy diets with university students being particularly vulnerable due to the assumption of responsibility for the acquisition of eating habits. Objective: The purpose of this research has been to fit the theorical model for the explication of the number of diets through percentage of body fat and body dissatisfaction through structural equations. The participants have been 244 Mexican college women, whose average age was 19.88 years (DE=1.24). The used tools have been the percentage body fat, the number of diets to lose weight for the last two years and the IMAGE Questionnaire to measure the different components of body dissatisfaction. Results: A satisfactory fit has been obtained, with most of the hypothesized relationships being significant. It is highlighted that only the change approach and the behavioral component have a direct effect on the number of diets. The mediating capacity of the body dissatisfaction factors between the variable's percentage of body fat and number of diets is also highlighted. Conclusions: Considering the total effect (direct and indirect effects), the behavioral component, followed by the emotional discomfort, perceptual discomfort and the change approach components of body dissatisfaction are the variables with the greatest explanatory power on the number of diets. The percentage of body fat shows no direct effect on the number of diets.

Modelos matemáticos aplicados a la Epidemiología / Mathematical models applied to Epidemiology / Modelos matemáticos aplicados à Epidemiologia

RESUMEN Un modelo matemático es una descripción matemática (a menudo por medio de una función o una ecuación) de un fenómeno del mundo real, como el tamaño de una población, la expectativa de vida de una persona al nacer o la propagación de una epidemia. Para ver la importancia de estos en las Ciencias de la Salud, específicamente en la especialidad de Higiene y Epidemiología mostramos dos de ellos para predecir el comportamiento de epidemias. El primero lo exponemos mediante una ecuación diferencial de 1er orden y el segundo mediante un sistema de ecuaciones diferenciales.

ABSTRACT A mathematical model is a mathematical description (often by means of a function or an equation) of a real-world phenomenon, such as the size of a population, the life expectancy of a person at birth, or the spread of an epidemic. To see the importance of these in Health Sciences, specifically in the specialty of Hygiene and Epidemiology, we show two of them to predict the behavior of epidemics. We expose the first through a 1st order differential equation and the second through a system of differential equations.

RESUMO Um modelo matemático é uma descrição matemática (frequentemente por meio de uma função ouequação) de um fenômeno do mundo real, como o tamanho de uma população, a expectativa de vida de uma pessoaao nascer ou a propagação de uma epidemia. Para perceber a importância destesnas Ciências da Saúde, especificamente na especialidade Higiene e Epidemiologia, mostramos dois deles para prever o comportamento de epidemias. Expomos o primeiro por meio de uma equação diferencial de 1ª ordem e o segundo por meio de um sistema de equaçõ es diferenciais.

Gee-logit model corrected biplots with harvest effects on coffee beans grading

In a granulometric analysis of coffee beans with different categories of defects, the data can be organized in contingency tables, and when considering the discrimination by harvest, they may have a structure that suggest a more complex model, by means of the counting of defective coffee beans compared to different crops interacting with the classification of defects and percentages of sieve grains, which characterizes a block design with multivariate responses. However, due to the techniques based on the analysis of variance, considering the uniform correlation structure for all plots, it becomes feasible to propose a model that allows contemplating different structures between the plots, associating the effects of the crops to the defects in the granulometric procedure applied to the coffee beans. Thus, the hypothesis of incorporating the effects of crops associated with defects arises using the biplot multivariate technique. This work aims to propose the use of corrected biplots by predictions obtained trhough the fit to the Generalized Linear Model in the coffee grain size classification, broken down by components of the effect of the harvests. In conclusion, the use of GEE models with the corrected biplot technique by the predictions is feasible for application to be applied to the granulometric analysis of defective coffee beans, presenting discrimination regarding the effects of harvests.

Allometric equations to estimate the leaf area of Psychotria colorata (Willd. Ex Schult.) Müll.Arg.

Estimating leaf area using non-destructive methods from regression equations has become a more efficient, quick, and accurate way. Thus, this study aimed to propose an equation that significantly estimates the leaf area of Psychotria colorata (Rubiaceae) through linear leaf dimensions. For this purpose, 200 leaves of different shapes were collected, and length (L), width (W), product of length by width (L.W), and real leaf area (LA) of each leaf blade were determined. Then, equations were adjusted for predicting leaf area using simple linear, linear (0.0), quadratic, cubic, power, and exponential regression models. The proposed equation was selected according to the coefficient of determination (R²), Willmott's agreement index (d), Akaike's information criterion (AIC), mean absolute error (MAE), mean squared error (RMSE) and BIAS index. It was noted that the equations adjusted using L.W met the best criteria for estimating leaf area, but the equation LA = 0.59 * L.W from linear regression without intercept was the most suitable. This equation predicts that 59% of leaf area is explained by L.W. Concluding, the leaf area of P. colorata can be estimated using an allometric equation that uses linear leaf blade dimensions.

Comparisons between intake values observed and predicted by nutritional systems for confined nellore cattle

This study compared the dry matter intake (DMI) of Nellore heifers and bulls in the feedlot, predicted by the BR-Corte (2010 and 2016) and NRC (2000) nutritional systems. Hence, two experiments were conducted in a completely randomized design. The first one used 47 Nellore bulls, not castrated, with an average initial weight of 413 kg, and 19 months of age. The second experiment used 24 Nellore heifers with an average initial weight of 300 kg and 23 months of age. The accuracy and approximation of the DMI estimates by the nutritional systems were adjusted with the simple linear regression model and the root mean square error of prediction (RMSEP). The DMI was 8.06 kg day-1 for Nellore heifers and 11.54 kg day-1 for bulls, which are higher than the values ​​ predicted by the nutritional systems. The NRC (2000) and BR-Corte (2010 and 2016) underestimated DMI in 20.84, 20.09, and 19.35% for heifers and 28.07, 16.20, and 11.78% for bulls, respectively. It was concluded that the BR-Corte 2010 and 2016 were the most suitable models to estimate the DMI of Nellore heifers and bulls for higher precision and accuracy.

Peripheral blood indicators in medical radiation workers in Yangpu District of Shanghai， 2017-2019 / 上海预防医学

Objective:To explore the impact of occupational ionizing radiation exposure on blood indicators including white blood cell（ WBC）， red blood cell （RBC）， hemoglobin （Hb）， platelet （PLT） were analyzed. Methods:A total of 237 medical radiation workers in Yangpu district， Shanghai were recruited and divided into observation group and control group， according to individual average dose of external exposure. The annual effective dose in observation group was 0.357 7-4.704 3 mSv， and the median dose was 0.536 8 mSv （0.441 2-0.893 8）. The annual effective dose in control group was 0.031 2-0.350 8 mSv， and the median dose was 0.199 2 mSv （0.143 8-0.252 8）. Routine blood tests were conducted twice in the occupational health examinations from 2017 to 2019 and the results were collected. Chi-square test， Mann-Whitney U test， and generalized estimating equations （GEE） model were used for statistical analysis. Results:Compared to the first examination， the risk of having abnormal Hb increased （OR=1.029， 95%CI： 1.006-1.053）. After adjusting the factors of age， gender， seniority and exposure time， the risk of Hb abnormality in the observation group was lower than that in the control group （OR=0.422， 95%CI：0.198-0.898）. There was no significant difference between the observation and control groups in the risk of abnormal WBC， RBC， and PLT. Conclusion:Exposure to occupational ionizing radiation may increase the risk of abnormal Hb， while there is no significant change in WBC， RBC and PLT. Radiation workers should have full protection at work and be under appropriate occupational health management.

Análisis Psicométrico de la Escala Orientación hacia la Dominancia Social (SDO) Mediante un Modelo de Ecuaciones Estructurales Exploratorias (ESEM) / Psychometric Analysis of the Social Dominance Orientation (SDO) Scale Through a Model of Exploratory Structural Equations (ESEM)

Resumen El objetivo de la presente investigación es analizar las propiedades psicométricas de la Escala Orientación hacia la Dominancia Social (SDO), en una muestra no universitaria de la ciudad de Arica, Chile, implementando técnicas psicométricas de acuerdo con el estado del arte disciplinar. El muestreo fue no probabilístico, por conveniencia y disponibilidad de 812 participantes, entre edades de 18 a 89 años. Se realizaron estimaciones de fiabilidad, análisis factoriales confirmatorios y modelos de ecuaciones estructurales exploratorios, contrastando diferentes modelos. Los resultados proporcionaron evidencia de validez basada en la estructura interna de la prueba, presentando buen ajuste de la estructura de la SDO (RMSEA=.076; CFI=.963; TLI=.956), y adecuados niveles estimados de fiabilidad (Oposición a la Igualdad: α=.85, ω=.84; Dominancia Grupal: α =.67, ω =.66). Finalmente, se concluye que las puntuaciones de la escala SDO poseen evidencia suficiente para sustentar su uso e interpretación, en población no universitaria equivalente a la del presente estudio.

Abstract The objective of this research is to analyze the psychometric properties of the Social Dominance Orientation (SDO) Scale in a non-university sample of the city of Arica, Chile, implementing psychometric techniques according to the state of disciplinary art. The sampling was non-probabilistic due to the convenience and availability of 812 participants in a range of ages from 18 to 89 years. To contrast different models were performed reliability estimates, confirmatory factorial analyses, and exploratory structural equation models. The results provided evidence of validity based on the internal structure of the test, presenting good adjustment of the SDO structure (RMSEA=.076; CFI=.963; TLI=.956), and estimated adequate levels of reliability (Opposition to the Equality: α=.85, ω=.84, Group dominance: α =.67, ω =.66). Finally, the research concluded that the scores of the SDO scale have sufficient evidence to support its use and interpretation, in a non-university population equivalent to that of the present study.

Concordance of estimated glomerular filtration rate according to the formulas used in Colombia for patients with chronic kidney disease not on dialysis / Concordancia de la filtración glomerular estimada según las fórmulas utilizadas en Colombia en pacientes con enfermedad renal crónica no en diálisis

Abstract Introduction: the Colombian guidelines for chronic kidney disease (CKD) recommend estimating glomerular filtration (GF) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. No studies have been performed in the Colombian population to compare the accuracy of this equation to that of others used in clinical practice. Design and methods: we evaluated the GF estimation performance of the Modification of Diet in Renal Disease (MDRD-4), Cockroft-Gault (CG) and body surface area adjusted Cockroft-Gault (CG-BSA) equations against the CKD-EPI equation in 757 adult patients. Performance was evaluated using bias, precision and accuracy measurements. Results: the mean GF by CKD-EPI was 37.32±12.71 mL/min/1.73m2; by MDRD-4 it was 39.8±13.2 mL/min/1.73m2, by CG it was 35±12.6 mL/min and by CG-BSA it was 34.52±11.34 mL/ min/1.73m2. All the equations had bias with respect to GF by CKD-EPI. The most accurate equation was GF estimated by MDRD-4 (MeGF) with 97.1 and 99.74% of measurements within 15 and 30%, respectively; and the least accurate was GF estimated by CG (CGeGF) with 59.7 and 81.77% of the measurements within 15 and 30%, respectively. The concordance correlation coefficient between GF by CKD-EPI and MDRD-4 was 0.97, with CG and CG-BSA at 0.78 and 0.85, respectively Conclusions: the most accurate alternative equation for estimating glomerular filtration in this Colombian population is MDRD-4, which has a high concordance with the CKD-EPI equation. Estimation of GF with the CG equation is not recommended.

Resumen Introducción: las guías colombianas de enfermedad renal crónica (ERC) recomiendan estimar la filtración glomerular (FG) con la fórmula de epidemiología de la enfermedad renal crónica (CKD-EPI). No se han realizado estudios que comparen en la población colombiana la exactitud de esta fórmula con otras utilizadas en la práctica clínica. Diseño y métodos: en 757 pacientes adultos evaluamos el desempeño para estimar la FG por las fórmulas de la modificación de la dieta en la enfermedad renal (MDRD-4), Cockroft-Gault (CG) y Cockroft-Gault corregida para la superficie corporal (CG-SC) comparada con la fórmula de CKD-EPI. El desempeño se evaluó con mediciones del sesgo, precisión y exactitud. Resultados: la media de la FG por CKD-EPI fue 37.32±12.71 mL/min/1.73m2, por MDRD-4 de 39.8±13.2 mL/min/1.73m2, por CG fue 35±12.6 mL/min y por CG-SC de 34.52±11.34 mL/ min/1.73m2. Todas las fórmulas tuvieron un sesgo con relación a la FG por CKD-EPI. La fórmula más exacta fue la FG estimada por MDRD-4 (FGeM) con una proporción de mediciones dentro del 15 y 30% en 97.1 y 99.74% de las mediciones respectivamente, y la menos exacta fue la FG estimada por CG (FGeCG) con 59.7 y 81.77% de las mediciones dentro del 15 y 30% respectivamente. El coeficiente de correlación de concordancia entre la FG por CKD-EPI y MDRD-4 fue de 0.97, con CG y CG-SC de 0.78 y 0.85, respectivamente. Conclusiones: la fórmula alterna más exacta para estimar la filtración glomerular en esta población colombiana es la MDRD-4 que tiene una alta concordancia con la fórmula de CKD-EPI. Se sugiere no utilizar la estimación de la FG con la fórmula de CG.

Consumption of dry matter observed and predicted by the nutritional systems in senepol bulls kept in confinement / Consumo de matéria seca observado e previsto pelos sistemas nutricionais em touros senepol mantidos em confinamento

The objective was to compare the dry matter consumption (CMS) observed, through the use of the GrowSafe® electronic system, with that predicted by the BR-Corte (2010 and 2016) and NRC (2000) nutritional systems in confined Senepol bulls. To this end, 24 Senepol Bulls were used in a completely randomized design, uncastrated with an average initial weight of 368 kg and 16 months of age. The evaluation of the accuracy and approximation of the CMS estimates by the nutritional systems was adjusted by the simple linear regression model and the decomposition of the mean square of the prediction error (QMEP). The mean CMS observed was 10.33 kg.day-1, higher than the values predicted by the nutritional systems, in which the values predicted by the NRC (2000) and BR-Corte 2010 and 2016 underestimated the CMS by 29.62, 6.19 and 2.03%, respectively. The verification of QMEP and its decomposition made it possible to infer the proximity of the values predicted by the BR-Corte 2010 and 2016 models and the values observed, which presented a better adjustment in relation to the NRC. Surprisingly the values predicted by the NRC, created from a database with Bos taurus animals, showed greater distance from the values predicted and observed, and it was expected greater accuracy of the NRC models for this category and animal breed. It is concluded that the BR-Corte 2016 was the most appropriate model to estimate the CMS of confined Senepol bulls.

Objetivou-se comparar o consumo de matéria seca (CMS) observado, por meio do uso do sistema eletrônico GrowSafe®, com o predito pelos sistemas nutricionais BR-Corte (2010 e 2016) e NRC (2000) em touros da raça Senepol em confinamento. Para isso, foram utilizados 24 Touros da raça Senepol em delineamento inteiramente casualizado, não castrados com peso inicial médio 368 kg e 16 meses de idade. A avaliação da exatidão e aproximação das estimativas do CMS pelos sistemas nutricionais foi ajustada pelo modelo de regressão linear simples e decomposição do quadrado médio do erro de predição (QMEP). O CMS médio observado foi de 10,33 kg.dia-1, valor superior aos valores preditos pelos sistemas nutricionais, no qual os valores preditos pelo NRC (2000) e BR-Corte 2010 e 2016 subestimaram o CMS em 29,62, 6,19 e 2,03%, respectivamente. A verificação do QMEP e sua decomposição possibilitou inferir sobre a proximidade dos valores preditos pelos modelos BR-Corte 2010 e 2016 e os valores observados, os quais apresentaram melhor ajuste em relação ao NRC. Surpreendentemente os valores preditos pelo NRC, criado a partir de banco de dados com animais Bos taurus, apresentou maior distanciamento dos valores preditos e observados, sendo que era esperada maior precisão dos modelos NRC para esta categoria e raça animal. Conclui-se que o BR-Corte 2016 foi o modelo mais adequado para estimar o CMS de touros da raça Senepol em confinamento.

Seria o ciúme mediador entre as experiências na família de origem e a violência física na conjugalidade? / Is jealousy a mediator between experiences in the family of origin and physical violence in conjugality? / Serián los celos mediadores entre las vivencias en la familia de origen y la violencia física en la conjugalidad?

A violência conjugal é um fenômeno multideterminado, o qual sofre impacto de experiências precoces e atuais. O objetivo deste estudo foi testar um modelo teórico no qual o ciúme é mediador entre as experiências na família de origem e a violência física conjugal. Trata-se de um estudo com delineamento quantitativo, transversal e explicativo. Contou com uma amostra de 600 pessoas, de 18 a 65 anos, residentes em 13 estados brasileiros. Os instrumentos foram questionário sociodemográfico, FBQ, CTS2 e ICR, em uma coleta por formulário eletrônico na internet. Modelagem de equações estruturais foi utilizada para testar a validade empírica do modelo teórico. Os resultados indicaram que o ciúme media parcialmente as experiências na família de origem e a ocorrência da violência conjugal. Os dados apontam para a necessidade de atenção ao ciúme nos relacionamentos amorosos, como forma de atuar na prevenção às situações de violência conjugal. (AU)

Conjugal violence is a multidetermined phenomenon, which is impacted by early and present experiences. The objective of this study was to test a theoretical model in which jealousy mediates between experiences in the family of origin and physical domestic violence. This was a quantitative, transversal, and explanatory study, which counted on a sample of 600 people, aged from 18 to 65 years, from 13 Brazilian states. The instruments included a sociodemographic questionnaire, the FBQ, the CTS2, and the RJI, all collected electronically. Structural equation modeling was used to test the empirical validity of the theoretical model. The results indicated that jealousy partially mediates the experiences in the family of origin and the occurrence of conjugal violence. The data point to the need for attention to jealousy in love relationships, as a way of acting in the prevention of situations of conjugal violence. (AU)

La violencia conyugal es un fenómeno multideterminado, el cual sufre impacto de experiencias tempranas y actuales. El objetivo de este estudio fue testar un modelo teórico en el cual los celos son mediadores entre las vivencias en la familia de origen y la violencia física conyugal. Se trata de un estudio con delineamiento cuantitativo, transversal y explicativo. Se contó con una muestra de 600 personas, de 18 a 65 años, residentes en 13 estados brasileños. Los instrumentos fueron el cuestionario sociodemográfico, FBQ, CTS2 e ICR, recogidos por medio de formulario electrónico en internet. El modelo de ecuaciones estructurales fue utilizado para testar la validez empírica del modelo teórico. Los resultados indicaron que los celos midieron parcialmente las vivencias en la familia de origen y la ocurrencia de la violencia conyugal. Los datos señalan la necesidad de atención de los celos en las relaciones amorosas, como forma de actuar en la prevención de las situaciones de violencia conyugal. (AU)