Nonparametric item response models: a comparison on recovering true scores / Modelos de resposta ao item não-paramétricos: comparando a recuperação de escores verdadeiros / Modelos de respuesta al item no-paramétricos: comparando la recuperación de puntuaciones verdaderas

Nonparametric procedures are used to add flexibility to models. Three nonparametric item response models have been proposed, but not directly compared: the Kernel smoothing (KS-IRT); the Davidian-Curve (DC-IRT); and the Bayesian semiparametric Rasch model (SP-Rasch). The main aim of the present study is to compare the performance of these procedures in recovering simulated true scores, using sum scores as benchmarks. The secondary aim is to compare their performances in terms of practical equivalence with real data. Overall, the results show that, apart from the DC-IRT, which is the model that performs the worse, all the other models give results quite similar to those when sum scores are used. These results are followed by a discussion with practical implications and recommendations for future studies.(AU)

Procedimentos não paramétricos são usados para adicionar flexibilidade aos modelos. Três modelos não paramétricos de resposta ao item foram propostos, mas não comparados diretamente: o Kernel smoothing (KS-IRT); a Curva Davidiana (DC-IRT); e o modelo semiparamétrico Rasch Bayesiano (SP-Rasch). O objetivo principal do presente estudo é comparar o desempenho desses procedimentos na recuperação de escores verdadeiros simulados, utilizando escores de soma como benchmarks. O objetivo secundário é comparar seus desempenhos em termos de equivalência prática com dados reais. De forma geral, os resultados mostram que, além do DC-IRT, que é o modelo que apresenta o pior desempenho, todos os outros modelos apresentam resultados bastante semelhantes aos de quando se usam somatórios. Esses resultados são seguidos de uma discussão com implicações práticas e recomendações para estudos futuros.(AU)

Se utilizan procedimientos no paramétricos para agregar flexibilidad a los modelos. Se propusieron tres modelos de respuesta al ítem no paramétricos, pero no se compararon directamente: Kernel smoothing (KS-IRT); la curva davidiana (DC-IRT); y el modelo bayesiano de Rasch semiparamétrico (SP-Rasch). El objetivo principal del presente estudio es comparar el desempeño de estos procedimientos en la recuperación de puntajes verdaderos simulados, utilizando puntajes de suma como puntos de referencia. El objetivo secundario es comparar su desempeño en términos de equivalencia práctica con datos reales. En general, los resultados muestran que, a excepción de DC-IRT, que es el modelo con peor desempeño, todos los otros modelos presentan resultados bastante similares a los obtenidos cuando se utilizan sumatorios. Estos resultados son seguidos por una discusión con implicaciones prácticas y recomendaciones para estudios futuros.(AU)

Correlación entre glucemia basal y alanina aminotransferasas en pacientes con y sin diabetes de un policlínico de Lima, Perú

Introducción: la alanina aminotransferasa es un nexo importante en el metabolismo de aminoácidos y carbohidratos, asimismo es un marcador de inflamación hepática. Estudios previos mostraron la relación entre la diabetes mellitus y esta enzima bajo diferentes contextos clínicos. Objetivo: evaluar la correlación entre glucosa basal y alanina aminotransferasa tanto en pacientes con diabetes mellitus tipo 2 como sin ella. Metodología: estudio observacional, analítico y transversal realizado desde enero de 2021 a junio de 2022 con una población de 566 pacientes dividida en grupos con diabetes mellitus tipo 2 (n 224) y sin diabetes mellitus tipo 2 (n 342). Fueron incluidos los pacientes de edad igual o mayor a 18 años con y sin diabetes mellitus tipo 2. Se excluyó a pacientes con patologías múltiples y/o con diagnóstico de diabetes inferior a 6 meses. Se realizó el análisis inferencial con la prueba de correlación de Spearman y la prueba de normalidad de Kolmogorov-Smirnov. Los datos fueron procesados con el software SPSS statistics 25™. Resultados: la correlación entre glucosa y alanina aminotransferasa en sujetos sin diabetes fue 0,212 (p=0,003) y la correlación entre glucosa y alanina aminotransferasa en aquellos con diabetes fue -0,434 (p=0,015). Conclusiones: la alanina aminotransferasa se relaciona con mayor intensidad en pacientes con diabetes mellitus tipo 2 que en aquellos sin diabetes. La correlación moderada y negativa en sujetos con diabetes mellitus tipo 2 indicaría alteraciones en la interacción entre la alanina aminotransferasa y la glucosa en los que la hiperglucemia sostenida tendría un papel relevante, probablemente por un incremento en la actividad de transaminación.

Introduction: Alanine aminotransferase is an important nexus in the metabolism of amino acids and carbohydrates, and is also a marker of liver inflammation. Previous studies showed the relationship between diabetes mellitus and this enzyme under different clinical contexts. Objective: To evaluate the correlation between basal glucose and alanine aminotransferase both in patients with and without type 2 diabetes mellitus. Methodology: Observational, analytical, and cross-sectional study conducted from January 2021 to June 2022 with a population of 566 patients divided into groups with type 2 diabetes mellitus (n 224) and without it (n 342). Patients aged 18 years or older with and without type 2 diabetes mellitus were included. Patients with multiple pathologies and/or diagnosed with diabetes less than 6 months were excluded. Inferential analysis was performed with Spearman's correlation test and the Kolmogorov-Smirnov normality test. The data was processed with the SPSS statistics 25™ software. Results: The correlation between glucose and alanine aminotransferase in subjects without diabetes was 0.212 (p=0.003) and the correlation between glucose and alanine aminotransferase in those with diabetes was -0.434 (p=0.015). Conclusions: Alanine aminotransferase is associated with greater intensity in patients with type 2 diabetes mellitus than in those without diabetes. The moderate and negative correlation in subjects with type 2 diabetes mellitus would indicate alterations in the interaction between alanine aminotransferase and glucose in which sustained hyperglycemia would play a relevant role, probably due to an increase in transamination activity.

Selection and application of statistical methods in medical research / 上海预防医学

Statistics plays an important role in medical research， and the selection of appropriate statistical methods is crucial for drawing reliable and valuable conclusions. This paper provides a brief introduction to commonly used statistical analysis methods for medical data， covering descriptive analysis， parametric test， nonparametric test， correlation analysis， regression analysis， and analysis of survival data. It focuses on discussing the assumptions of multiple linear regression， logistic regression and Cox proportional risk regression， as well as how to choose the appropriate statistical methods for analyzing and interpreting medical data based on different research objectives and data types.

Necessity and methodological progress on the establishment of continuous reference intervals for pediatric age-dependent indicators / 中华检验医学杂志

Accurate and applicable reference intervals can provide important information for disease diagnosis, efficacy evaluation, and health monitoring. Age-dependent trends exist for many clinical laboratory indicators, and the interpretation of such indicators should consider the effect of age carefully. However, age-specific reference intervals have certain limitations in clinical application. Continuous reference intervals can not only help accurate interpretation of laboratory test results, but also provide a baseline value for dynamic monitoring of their changing trends. Based on the researches on pediatric reference intervals from our team, this paper introduces different algorithms for establishing continuous reference intervals, and their applicable conditions and implementation steps. The aim of this paper is to provide methodological guidance for the establishment of continuous reference intervals, so as to improve the quality of laboratory reports and the accuracy of clinical diagnosis in China.

Correlation analysis between post-stroke depression and serum bilirubin and high-sensitivity C-reactive protein / 中国基层医药

Objective:To analyze the influential factors of post-stroke depression and investigate the effects of changes in serum bilirubin and high-sensitivity C-reactive protein on post-stroke depression.Methods:A total of 199 patients with stroke admitted to Qinghai Provincial People's Hospital from December 2019 to December 2020 were included in this study. These patients were divided into the Xining urban group (2 000-3 000 meters above sea level; n = 165) and the Xining prefecture and county group (over 3 000 meters above sea level; n = 34) according to their long-term residence. They were also divided into the post-stroke depression group ( n = 56, including 45 patients in the Xining urban group and 11 patients in the Xining prefecture and county group) and non-post-stroke depression group ( n = 143, including 120 patients in the Xining urban group and 23 patients in the Xining prefecture and county group). Related scales were used to evaluate neurologic deficits and the degree of depression in the two groups. Serum levels of total bilirubin, direct bilirubin, and high-sensitivity C-reactive protein were measured in each group. Neurologic deficits and the degree of depression were correlated with serum levels of total bilirubin, direct bilirubin, and high-sensitivity C-reactive protein. Results:Serum levels of total bilirubin, direct bilirubin, and high-sensitivity C-reactive protein in the post-stroke depression group were (19.95 ± 7.22) mmol/L, (3.98 ± 1.49) mmol/L, and (1.40 ± 2.29) mg/L, respectively, which were significantly higher than (16.20 ± 7.61) mmol/L, (3.19 ± 1.62) mmol/L, and (0.63 ± 1.33) mg/L in the non-post-stroke depression group ( t = 3.17, 3.18, 2.35, all P < 0.05). There was a significant difference in serum level of high-sensitivity C-reactive protein between stroke patients with mild and moderate depression and stroke patients with severe depression ( t = 2.48, P < 0.05). Conclusion:Serum levels of bilirubin and high-sensitivity C-reactive protein play an important role in the pathogenesis of post-stroke depression and there is a significant correlation between the two.

Correlación del recuento de eosinófilos con las proteínas totales y la fosfatasa alcalina en pacientes asintomáticos con niveles normales y elevados de aspartato aminotransferasa de un policlínico de Villa El Salvador en Lima-Perú

Objetivo: Evaluar la correlación del recuento diferencial de eosinófilos con niveles de proteínas totales y fosfatasa alcalina en pacientes con valores normales y elevados de aspartato aminotransferasa pertenecientes a un policlínico de Villa El Salvador en Lima, Perú. Materiales y métodos: Estudio observacional, analítico y correlacional realizado en pacientes de ambos sexos con edades iguales o mayores a 18 años, aparentemente sanos, con niveles normales y elevados de la enzima aspartato aminotransferasa. 279 pacientes cumplieron con los criterios de elegibilidad. Se utilizó la prueba de correlación de Spearman para determinar grado de correlación entre recuento de eosinófilos con fosfatasa alcalina y proteínas totales en pacientes con niveles normales y elevados de aspartato aminotransferasa. Resultados: No hubo correlación entre las variables estudiadas en el grupo con valores de aminotransferasas normales. Sin embargo, en el grupo que presentó valores de aspartato aminotransferasa elevados se encontró una correlación moderada y negativa entre el recuento de eosinófilos con las proteínas totales (Rho = -465) y correlación baja y positiva con la fosfatasa alcalina (Rho = 296). Conclusiones: En presencia de valores de aminotransferasas superiores al rango normal, los eosinófilos se correlacionan con las proteínas totales y la fosfatasa alcalina. Son necesarios estudios con mayor número de pacientes y complejidad metodológica para determinar si la interacción entre eosinófilos con la albúmina y la fosfatasa ocurre frecuentemente en condiciones de aminotransferasas elevadas, y considerar posibles implicaciones en la fisiopatología de las enfermedades crónicas asociadas a esta enzima, así como posibles repercusiones clínicas y terapéuticas.

Objective: To evaluate the correlation between eosinophil differential count and total protein and alkaline phosphatase levels in patients with normal and high levels of aspartate aminotransferase from a polyclinic in the district of Villa El Salvador in Lima, Peru. Materials and methods: An observational, analytical and correlational study conducted with apparently healthy male and female patients aged 18 years or older, showing normal and high levels of enzyme aspartate aminotransferase. The study included 279 patients who met the eligibility criteria. Spearman's correlation coefficient was used to determine the correlation between eosinophil count and alkaline phosphatase and total protein in patients with normal and high levels of aspartate aminotransferase. Results: No correlation was found between the variables studied in the group with normal levels of aminotransferases. However, in the group with high levels of aspartate aminotransferase, a moderate and negative correlation was found between eosinophil count and total protein (Rho = -465) and a low and positive correlation between eosinophil count and alkaline phosphatase (Rho = 296). Conclusions: In the presence of aminotransferase levels above the normal range, eosinophils correlate with total protein and alkaline phosphatase. Further studies with a larger number of patients and greater methodological complexity are necessary to determine if the interaction between eosinophils and albumin and phosphatase is frequently seen with high levels of aminotransferases. Moreover, they are necessary to consider possible implications in the pathophysiology of chronic diseases associated with this enzyme, as well as possible clinical and therapeutic implications.

El método de consulta a expertos en tres niveles de validación / Method for expert consultation at three levels of validation

Introducción: En muchas investigaciones científicas de las Ciencias Sociales, es usual la aplicación del método de consulta a expertos con el fin de validar escalas, enfoques, proyecciones, políticas y otros temas para la adopción de decisiones fundamentadas, aunque se constata su empleo parcial, indiscriminado e incorrecto. Objetivo: Fundamentar la necesidad de aplicar el método de consulta a expertos en tres niveles para determinar: la competencia de los expertos; la fiabilidad del instrumento empleado y el consenso entre los expertos sobre el tema abordado. Material y Métodos: Se realizó una sistematización de documentos relacionados con el empleo del método de consulta de expertos en la investigación científica, tesis de doctorado y maestría, artículos, monografías y otras publicaciones. Se aplicaron pruebas estadísticas no paramétricas. Resultados: Se constata que la aplicación del método de consulta a expertos siguiendo los procedimientos adecuados, permite elevar el rigor metodológico y su contribución en la investigación científica. Conclusiones: El método de consulta a expertos constituye una herramienta eficaz en la investigación científica siempre que se aplique con el rigor requerido(AU)

Introduction: The method for expert consultation is commonly applied to scientific research conducted in the Social Sciences to validate scales, approaches, planning, politics, and other matters in decision making; however, its incorrect, indiscriminate, and partial use is confirmed. Objective: To validate the need to apply the method for expert consultation at three levels in order to determine: the competence of experts; the reliability of the instrument used; and the consensus among experts on the topic approached. Material and Methods: Systematization of documents related to the use of the method for expert consultation in scientific research, master´s and doctoral theses, articles, monographs, and other publications. Non-parametric statistical tests were applied. Results: It is confirmed that the application of the method for expert consultation following the appropriate procedures allows for an increase in the methodological rigor and a contribution to scientific research. Conclusions: The method for expert consultation is an effective tool in scientific research provided that it is rigorously applied(AU)

Theoretical and Practical Foundations of Mokken Scale Analysis in Psychology / Fundamentos Teóricos e Práticos da Análise de Escala de Mokken em Psicologia / Fundamentos Teóricos y Prácticos del Análisis de la Escala de Mokken en Psicología

Abstract Item Response Theory represents one of the major advances in the field of developing valid and reliable measures in psychology. Among the main models used in this perspective are the Rasch model and the logistic models. These parametric models, however, are not suitable for all applications in psychology, since a substantial number of databases in psychology do not satisfy the assumptions of these models: unidimensionality; latent monotonicity; local independence; and, for some models, non-intersecting functions. Given this framework, the objective of this study was to present the theoretical and practical foundations of Mokken Scale Analysis (MSA). We present some historical issues involving the development of MSA, in addition to the main characteristics and assumptions of the two models used in this perspective. After exemplifying a MSA application, limitations and final considerations are presented, supporting the decision-making process for researchers who come to use MSA.

Resumo A Teoria de Resposta ao Item representa um dos principais avanços para a construção de medidas válidas e confiáveis em psicologia. Entre os principais modelos utilizados nessa perspectiva estão o modelo de Rasch e os modelos logísticos. Esses modelos paramétricos, no entanto, não podem ser utilizados em todas as aplicações em psicologia, uma vez que um número substancial dos bancos de dados em psicologia não satisfaz os pressupostos desses modelos: unidimensionalidade; monotonicidade latente; independência local; e, para alguns modelos, não-interseção de funções. Dessa forma, o objetivo deste estudo foi apresentar os fundamentos teóricos e práticos da Análise de Escala de Mokken (AEM). São apresentadas questões históricas envolvendo o desenvolvimento da AEM, além das principais características e pressupostos dos dois modelos usados nessa perspectiva. Após exemplificação de uma AEM, limitações e considerações finais são apresentadas, apoiando o processo de tomada decisão para pesquisadores que venham a usar a AEM.

Resumen La Teoría de Respuesta al Ítem representa uno de los mayores avances en el campo del desarrollo de medidas válidas en psicología. Entre los principales modelos utilizados en esta perspectiva se encuentran los modelos logísticos. Estos modelos no son adecuados para todas las aplicaciones en psicología, ya que algunas bases de datos en psicología no satisfacen las suposiciones de estos modelos: unidimensionalidad; monotonicidad latente; e independencia local; y, para algunos modelos, funciones que no se interceptan. Teniendo en cuenta este marco, el objetivo de este estudio fue presentar los fundamentos teóricos y prácticos del Análisis de la Escala de Mokken (AEM). Presentamos algunas cuestiones históricas relacionadas con el desarrollo de AEM, además de las principales características y suposiciones de los dos modelos utilizados en esta perspectiva. Después de ejemplificar un AEM, se presentan las limitaciones y consideraciones finales, apoyando o procesando la tomada de decisión para investigadores que van a usar el AEM.

How to use χ2 test correctly——the likelihood ratio test and the six nonparametric tests of the survival data and the implementation of the SAS software / 四川精神卫生

The purpose of this article was to introduce the likelihood ratio test， six nonparametric tests， and the SAS implementation of the survival data. Based on the assumption that the survival data had the exponential distribution， the likelihood ratio test method was derived， the main difference between six nonparametric test methods was that they had different weight functions. Under the conditions of non-stratification and stratification， the seven survival data hypothesis testing methods mentioned above could be used， and their common point was that their test statistics all followed the χ2 distribution. Through two examples and by means of the SAS software， the article realized the various hypothesis tests for two or more groups of survival data， outputed and explained SAS calculation results， and made statistical and professional conclusions.

Círculos de Reflexión y lógica P2P: Una alternativa didáctica a la Colonización del MOOC / P2P Reflection and Logic Circles: A Didactic Alternative to MOOC Colonization

Resumen En la era digital, es importante transitar hacia una Educación Popular Transmedia. El concepto es una articulación entre la tradición histórica latinoamericana iniciada por Paulo Freire y el reconocimiento de la categoría Transmedia de Scolari (2018) como la más adecuada para definir el conjunto de saberes implicados en la vivencia activa en comunidades híbridas virtuales/análogas. En este orden, la estrategia implementa da desde el modo de enseñanza online y la constitución de comunidad del Instituto de Pensamiento y Cultura en América Latina (Ipecal) se constituye en una apuesta esencial y de sentido.

Abstract In the digital age, it is important to move towards a Transmedia People's Education. The concept is an articulation between the Latin American historical tradition, initia ted by Paulo Freire, and the recognition of the Transmedia category by Scolari (2018) as the most suitable one to define the set of knowledge involved in the active expe rience in virtual/analog hybrid communities. In this order, the strategy implemented from the online teaching mode and the community constitution of the Institute of Thought and Culture in Latin America (Ipecal) is an essential and meaningful com mitment.

Relación entre índice de masa corporal y trastorno por déficit de atención con hiperactividad en niños / Relationship between body mass index and attention deficit disorder with hyperactivity in children

Introducción: El índice de masa corporal es un indicador de la densidad corporal. El trastorno por déficit de atención con hiperactividad es un síndrome que presenta tres síntomas: inatención, hiperactividad e impulsividad. Objetivo: Analizar la relación entre el índice de masa corporal y el trastorno por déficit de atención con hiperactividad en niños. Métodos: Investigación observacional, transversal, analítica bivariada y ambispectiva, desarrollada en 111 niñas y 125 niños, de 10 a 12 años de edad estudiantes de la Unidad Educativa Hispano América de la ciudad de Ambato, Ecuador, en el período septiembre 2017- febrero 2018. Los datos del índice de masa corporal y el trastorno por déficit de atención se procesaron en Microsoft Excel, el software Minitab® 18.1 para el cálculo de los coeficientes de correlación de Pearson y Spearman, y prueba de Grubbs para comprobar normalidad y análisis de valores atípicos. Resultados: La media del índice de masa corporal fue de 20,15 en niños y 20,63 en niñas, lo que se consideró normal. El trastorno por déficit de atención: 93,7 por ciento de niñas y 90,4 por ciento de niños, también fue normal. En estos últimos, existió una ligera predisposición por este trastorno. La correlación entre ambas variables fue ligeramente positiva: niñas 0,02 y niños 0,457. Conclusiones: El índice de masa corporal y el trastorno por déficit de atención con hiperactividad tienen parámetros normales en niñas y niños y existe entre ambos una correlación positiva débil. Es necesario establecer estrategias educativas para la disminución de la obesidad y malnutrición infantil(AU)

Introduction: The body mass index is an indicator of body density, determined by the relationship between body weight and height. Attention deficit hyperactivity disorder is a syndrome with three symptoms: inattention, hyperactivity and impulsivity. Objective: To analyze the relationship between the body mass index and the attention deficit hyperactivity disorder in students. Methods: Observational, cross-sectional, bivariate and ambispective analytical research, carried out in a population of 111 girls and 125 boys, from 10 to 12 years of the Hispanic American Education Unit of the city of Ambato, Ecuador, in the period September 2017 - February 2018. Processing data in Microsoft Excel for body mass index and for the attention deficit hyperactivity disorder, and with Minitab® 18.1 software for the calculation of coefficients of Pearson and Spearman correlation, as well as the normality tests and analysis of outliers with the Grubbs test. Results: The average for body mass index was 20.15 in boys and 20.63 in girls, considered normal. Normal results were obtained in the attention deficit hyperactivity disorder in 93.7 percent of girls and 90.4 percent of boys, there being a slight predisposition for this disorder. The correlation between both variables was slightly positive: girls 0.202 and boys 0.457. Conclusions: Both, body mass index and the attention deficit hyperactivity disorder have normal parameters in girls and boys, with a weak positive correlation between them. It was proposed to establish educational strategies for the reduction of obesity and child malnutrition(AU)

Validation of a new method for estimating low platelet counts: G&S method / Validação de um novo método para estimação de contagens plaquetárias baixas: método G&S

ABSTRACT Introduction: Automated hematology analyzers are able to produce low platelet counts with great precision and accuracy. However, these analyzers may produce erroneous counts due to the presence of interferences. Therefore, additional methodologies are required to confirm platelet counts, such as blood smear and a direct count, using the Neubauer chamber. Objective: To validate the reliability estimate produced by the G&S method. Material and method: One hundred and fifty platelet counts were analyzed in the hematology and emergency laboratories of the Hospital Nacional Docente Madre-Niño San Bartolomé, in Lima, Peru, by four methodologies: one optical platelet count (PLTO), one indirect blood smear count (Indirect), and two direct counts (Direct and G&S). Descriptive and inferential statistics were used to compare the groups. Results: A significant difference was observed in the distribution of the four methodologies and, after applying the post-hoc analysis, a similarity between the PLTO and G&S methods was found. Also, the Direct, G&S and Indirect methods showed a positive correlation with the PLTO method. The Bland-Altman test demonstrated that the G&S method presented a high agreement with the PLTO method. Conclusion: The G&S method is inexpensive, easy to perform, and has demonstrated statistical reliability concerning the automated methodology, and is useful for confirming low platelet counts after a suspected error by the automated equipment or when this device is not available for use.

RESUMEN Introducción: Los analizadores automáticos hematológicos son capaces de realizar bajos recuentos de plaquetas con precisión y exactitud. Sin embargo, eses analizadores pueden producir recuentos erróneos debido a la presencia de interferencias. Así, métodos adicionales son necesarios para confirmar los recuentos de plaquetas, como el frotis de sangre y un recuento directo en cámara de Neubauer. Objetivo: Validar la confiabilidad de la estimación del método G&S. Material y método: Se analizaron ciento cincuenta recuentos de plaquetas en los laboratorios de hematología y emergencias del Hospital Nacional Docente Madre-Niño San Bartolomé, en Lima, Perú, por cuatro métodos: un recuento óptico de plaquetas (PLTO), un recuento indirecto por frotis de sangre (Indirecto) y dos recuentos directos (Directo y G&S). Se utilizaron estadísticas descriptivas e inferenciales para comparar los grupos. Resultados: Se observó diferencia significativa en la distribución de los cuatro métodos y, luego de la aplicación del análisis post-hoc, se encontró similitud entre los métodos PLTO y G&S. Además, los métodos Directo, G&S e Indirecto mostraron correlación positiva con el método PLTO. La prueba de Bland-Altman demostró que el método G&S presentó alta concordancia con el método PLTO. Conclusión: El método G&S es económico, fácil de llevar a cabo y demostró confiabilidad estadística en relación con el método automatizado, siendo útil para confirmar bajos recuentos de plaquetas después de una sospecha de error por el equipo automático o cuando el laboratorio no cuente con éste.

RESUMO Introdução: Os analisadores automatizados hematológicos são capazes de realizar baixas contagens de plaquetas com precisão e exatidão. No entanto, esses analisadores podem produzir contagens erradas devido à presença de interferências. Dessa forma, métodos adicionais são necessários para confirmar as contagens de plaquetas, como esfregaço de sangue e uma contagem direta, utilizando a câmara de Neubauer. Objetivo: Validar a confiabilidade gerada pela estimativa do método G&S. Material e método: Cento e cinquenta contagens de plaquetas foram analisadas nos laboratórios de hematologia e emergência do Hospital Nacional Docente Madre-Niño San Bartolomé em Lima, Peru, por quatro metodologias: uma contagem óptica de plaquetas (PLTO), uma contagem indireta por esfregaço de sangue (Indireto) e duas contagens diretas (Direto e G&S). Estatísticas descritivas e inferenciais foram utilizadas para comparar os grupos. Resultados: Observou-se diferença significativa na distribuição das quatro metodologias e, após a aplicação da análise post-hoc, obteve-se semelhança entre os métodos PLTO e G&S. Além disso, os métodos Direto, G&S e Indireto mostraram correlação positiva com o método PLTO. O teste de Bland-Altman demonstrou que o método G&S apresentou alta concordância com o método PLTO. Conclusão: O método G&S é barato, fácil de executar e demonstrou confiabilidade estatística em relação à metodologia automatizada, sendo útil para confirmar baixas contagens de plaquetas após uma suspeita de erro pelo equipamento automatizado ou quando não se tem esse aparelho disponível para uso.

La relación de la edad con los componentes espectrales de las realizaciones sin ruido de señales fotopletismográficas: resultados de un enfoque de identificación no lineal / Relationship of Age with Spectral Components of Noise-Free Realizations of Photoplethysmographic Signals: Outcomes of a Nonlinear Identification Approach

Background: Age-related changes in the vascular network have been widely documented, however, nonlinear identification has been poorly applied to the analysis of cardiovascular signals. Objective: To determine the impact of age on spectral components of Noise-free realizations (NFR) obtained from photoplethysmographic signals, summarized in the Kernel Complexity Regressive Index (KCRIndex). Methods: With 190 apparently healthy participants (9 to 89 years) from Orense, Spain, Photoplethysmographic signals were recorded during 5 minutes in supine position using Nellcor-395 pulse oximeter; signals were digitized at 1000 Hz, and furtherly submitted to nonlinear identification via a kernel nonlinear autoregressive estimator. KCRIndex is defined as the average of at least three negative slope values at the NFR log-log spectrum in the 9 to 25 Hz frequency region. Results: KCRIndex decreased with age in a linear fashion and did not differ between genders. The regression line obtained was KCRIndex=-0.025*age+6.868 (r=-0.751). Conclusions: KCRIndex, is strongly correlated with age, thus opening up new possibilities for cardiovascular exploration at primary health care settings and even on open field conditions(AU)

Antecedentes: los cambios relacionados con la edad en la red vascular se han documentado ampliamente, sin embargo, la identificación no lineal solo se ha aplicado de manera esporádica al análisis de las señales cardiovasculares. Objetivo: determinar los cambios con la edad en los componentes espectrales de las realizaciones sin ruido (NFR) obtenidas a partir de señales fotopletismográficas, resumidas en el índice regresivo de la complejidad por núcleos (KCRIndex). Métodos: Con 190 participantes aparentemente sanos (de 9 a 89 años) residentes en Orense, España, se registraron señales fotopletismográficas durante 5 minutos en posición supina usando un oxímetro de pulso Nellcor-395; las señales se digitalizaron a 1000 Hz, y se sometieron a identificación no lineal a través de un estimador autorregresivo no lineal por núcleos. El KCRIndex se define como el promedio de al menos tres valores de pendiente negativos en el espectro log-log de NFR en la región de frecuencia de 9 a 25 Hz. Resultados: KCRIndex disminuyó con la edad de forma lineal y no difirió entre géneros. La línea de regresión obtenida fue KCRIndex = -0.025 * edad + 6.868 (r = -0.751). Conclusiones: Este índice propuesto está fuertemente correlacionado con la edad, lo que abre nuevas posibilidades para la exploración cardiovascular en entornos de atención primaria de salud e incluso en condiciones de campo(AU)

Selection of appropriate statistical methods for data analysis

In biostatistics, for each of the specific situation, statistical methods are available for analysis and interpretation of the data. To select the appropriate statistical method, one need to know the assumption and conditions of the statistical methods, so that proper statistical method can be selected for data analysis. Two main statistical methods are used in data analysis: descriptive statistics, which summarizes data using indexes such as mean and median and another is inferential statistics, which draw conclusions from data using statistical tests such as student's t-test. Selection of appropriate statistical method depends on the following three things: Aim and objective of the study, Type and distribution of the data used, and Nature of the observations (paired/unpaired). All type of statistical methods that are used to compare the means are called parametric while statistical methods used to compare other than means (ex-median/mean ranks/proportions) are called nonparametric methods. In the present article, we have discussed the parametric and non-parametric methods, their assumptions, and how to select appropriate statistical methods for analysis and interpretation of the biomedical data.

Prueba de interacción en el análisis molecular de varianza / Test of interaction in the analysis of molecular variance

La diversidad genómica, expresada en las diferencias entre haplotipos moleculares de un conjunto de individuos, puede dividirse en componentes de variabilidad entre y dentro de algún factor de clasificación de los individuos. Para tal partición de varianzas, se usa análisis molecular de la varianza (AMOVA), el cual se construye a partir de las distancias multivariadas entre pares de haplotipos. El AMOVA clásico permite evaluar la significancia estadística de dos o más factores jerárquicos y consecuentemente no existe prueba de interacción entre factores. Sin embargo, existen situaciones donde los factores que clasifican a los individuos están cruzados y no anidados, es decir todos los niveles de un factor se encuentran representados en cada nivel del otro factor. Este trabajo propone una prueba estadística para evaluar la interacción entre factores cruzados en un AMOVA No-Jerárquico. La hipótesis nula de interacción establece que las diferencias moleculares entre individuos de distintos niveles de un factor son las mismas para todos los niveles del otro factor que los clasifica. La propuesta de análisis de interacción de factores a partir de distancias en un AMOVA No-Jerárquico comprende: cálculo de la matriz de distancia y partición de la misma en bloques, posterior cálculo de residuos y análisis de varianza no-paramétrico sobre los residuos. Su implementación es ilustrada en escenarios simulados y real. Los resultados sugieren que la prueba de interacción propuesta para el AMOVA No- Jerárquico presenta alta potencia.

The genomic diversity, expressed in the differences between molecular haplotypes of a group of individuals, can be divided into components of variability between and within some factor of classification of the individuals. For such variance partitioning, molecular analysis of variance (AMOVA) is used, which is constructed from the multivariate distances between pairs of haplotypes. The classical AMOVA allows the evaluation of the statistical significance of two or more hierarchical factors and consequently there is no interaction test between factors. However, there are situations where the factors that classify individuals are crossed rather than nested, that is, all the levels of a factor are represented in each level of the other one. This paper proposes a statistical test to evaluate the interaction between crossed factors in a Non-Hierarchical AMOVA. The null hypothesis of interaction establishes that the molecular differences between individuals of different levels of a factor are the same for all the levels of the other factor that classifies them. The proposed analysis of interaction in a Non- Hierarchical AMOVA includes: calculation of the distance matrix and partition of it into blocks, subsequent calculation of residuals and analysis of non-parametric variance on the residuals. Its implementation is illustrated in simulated and real scenarios. The results suggest that the proposed interaction test for the Non-Hierarchical AMOVA presents high power.

Identification of dysphonia related to parkinson’s disease using parametric and non parametric models / 国际药学研究杂志

Classification of Parametric and Non Parametric models is done by using the collected dataset of Parkinson's disease. Testing is done on Parkinson’s data set with two respective models to determine which model provides the higher classification accuracy. Logistic Regression technique is used to classify the Parkinson's data using non parametric modeling and K-Nearest Neighbors and Random Forest Algorithm is used to classify the training and test data of Parkinson’s disease for parametric model. Based on the data classification,, we obtain the result using parametric and non parametric models. Finally, Comparison is made on of both Parametric and Non Parametric model to evaluate the performance of the Parkinson's dataset.

Estudio Clínico y Epidemiológico de Cáncer de Próstata en el Hospital de Especialidades José Carrasco Arteaga de Cuenca - Ecuador, 2010 - 2015 / Analytical Research: Clinical and Epidemiological Study of Prostate Cancer at the José Carrasco Arteaga Specialty Hospital in Cuenca - Ecuador, 2010 - 2015

INTRODUCCIÓN: El cáncer de próstata es el quinto tipo de neoplasia más frecuente a nivel mundial y el segundo en varones. En Cuenca, según el sexto informe de epidemiologia del cáncer es la segunda causa de muerte en hombres. MÉTODOS: Estudio descriptivo observacional, la muestra se seleccionó por conveniencia, 315 pacientes con biopsia positiva. Las variables establecidas fueron: signos y síntomas, tipo histológico, valor de antígeno prostático específico, factores de riesgo, escala de Gleason, grado de diferenciación y estadio clínico. Se obtuvo media, mediana y se realizó el cruce de variables utilizando coeficiente de Pearson y Spearman; fueron analizados en base al software STATA versión 12. RESULTADOS: Los síntomas más frecuentes fueron polaquiuria (56.2 %) y disuria (36.8 %). 312 presentaron histopatología de adenocarcinoma de próstata. El PSA total al diagnóstico tuvo una mediana de 14.4 ng/ml y media de 34 ng/ml. La media de edad fue 69 años. 141 pacientes presentaron hipertensión arterial. El grado de diferenciación en su mayoría fueron moderadamente diferenciados (43.6 %). El 67 % de pacientes se encontraron en estadio I y II de Gleason. Se evidencia un valor de Rho de 0.44 entre etapa clínica y Gleason, de 0.36 entre PSA y etapa clínica. CONCLUSIONES: Se encontró una asociación positiva moderada entre etapa clínica y Gleason. No existe un valor mínimo de PSA total que nos confirme la ausencia de riesgo para cáncer de próstata. Se invita a llevar a cabo estudios prospectivos en busca de relación entre cáncer de próstata y factores de riesgo.

BACKGROUND: Prostate cancer is the fifth most common neoplasms worldwide and the second in man. In Cuenca, according to the sixth epidemiology of cancer, it is the second cause of death in males. METHODS: Observational descriptive study the sample was for convenience, made up with 315 patients with positive biopsy. The established variables were: Signs and symptoms, histopathological type, total prostate specific antigen (PSA) measure, risk factors, Gleason score, differentiation grade and clinical staging. The media and median were obtained as the crossing of variables using Pearson and Spearman correlation coefficient. The software used was STATA 12 version. RESULTS: The most common symptoms were urinary frequency (56.2 %) and dysuria (36.8 %). 312 patients presented adenocarcinoma as histopathology type. The total PSA had a median of 4.4 ng/ml and a media of 34 ng/ml. The media of age was 69 years old. 141 patients presented hypertension. About the Gleason Grading system most of people were moderately differentiated (43.6 %). 67 % of cases were diagnosed during stages I and II. The Rho correlation coefficient was 0.44 between clinical stage and Gleason score; it was of 0.36 between PSA and clinical stage. CONCLUSIONS: It was found a moderately positive association between clinical stage and Gleason score. There is no minimal measure of total PSA that could assure us there is no risk of prostate cancer. More prospective studies are needed in order to find the relation between prostate cancer and risk factors.

The Average Annual Percent Change Analyzes of Preventive Dental Care in the Slovak Republic, 2014-2016

Objective: To analyse of the average annual percent change (AAPC) of registered dental patients, patients with preventive dental care and patients requiring dental treatment in the period of 2014-2016 in the Slovak Republic. Material and Methods: Data from registered dental patients (n=14,736,888), patients with preventive dental care (n=8,212,441) and patients requiring dental treatment (n=5,262,323) in the period of 2014-2016 were obtained from the Statistical Office of the Slovak Republic; 28,211,652 dental patients were analysed. The Theil-Sen estimator of trend line based on median and its significance was tested by nonparametric Wilcoxon test using statistical software R package. Results: The significant decrease (-4.11%) of the AAPC rates of registered dental patient (p<0.05) during the entire period (2014-2016) can be observed in age subcategory 15-18 years, while in age subcategory 19+ years the nonsignificant increase (1.08%) of the AAPC rate of registered dental patients in the same period was achieved. In the period of 2014-2016, the highest AAPC rate of patients with preventive dental care with the significant decrease was found in age subcategory 6-14 years (-17.19%; p<0.001). The AAPC rate of patients requiring dental treatment proved the significant negative values in age subcategory 0-5 years (-7.26%; p<0.01), in age subcategory 6-14 years (-9.33%; p<0.001), in age subcategory 15-18 years (-8.81%; p<0.01). Conclusion: The highest decrease AAPC rate of registered dental patients was observed in age subcategory 15-18 years. The statistical significant decrease AAPC rate of patients with preventive dental care was found in children ≤ 18 years. In patients requiring dental treatment (≤ 18 y.) was observed decrease AAPC rate.

Trends in statistical methods in articles published in Archives of Plastic Surgery between 2012 and 2017

This review article presents an assessment of trends in statistical methods and an evaluation of their appropriateness in articles published in the Archives of Plastic Surgery (APS) from 2012 to 2017. We reviewed 388 original articles published in APS between 2012 and 2017. We categorized the articles that used statistical methods according to the type of statistical method, the number of statistical methods, and the type of statistical software used. We checked whether there were errors in the description of statistical methods and results. A total of 230 articles (59.3%) published in APS between 2012 and 2017 used one or more statistical method. Within these articles, there were 261 applications of statistical methods with continuous or ordinal outcomes, and 139 applications of statistical methods with categorical outcome. The Pearson chi-square test (17.4%) and the Mann-Whitney U test (14.4%) were the most frequently used methods. Errors in describing statistical methods and results were found in 133 of the 230 articles (57.8%). Inadequate description of P-values was the most common error (39.1%). Among the 230 articles that used statistical methods, 71.7% provided details about the statistical software programs used for the analyses. SPSS was predominantly used in the articles that presented statistical analyses. We found that the use of statistical methods in APS has increased over the last 6 years. It seems that researchers have been paying more attention to the proper use of statistics in recent years. It is expected that these positive trends will continue in APS.

Avaliação da geração de resíduos sólidos urbanos no estado de Goiás, Brasil: análise estatística de dados / Municipal solid waste generation assessment in the state of Goiás, Brazil: statistical data analysis

RESUMO A definição do sistema de gestão de resíduos sólidos urbanos (RSU) mais adequado para um município passa, obrigatoriamente, pelo quantitativo de RSU gerados. O estado de Goiás enfrentava esse problema, pois alguns de seus municípios possuíam a informação do quantitativo de RSU produzidos, mas o estado não tinha um valor da geração total. Diante dessa questão, foi encaminhado um questionário aos municípios goianos em que se buscou obter informações acerca dos resíduos sólidos, dentre as quais a geração de RSU. O objetivo deste estudo foi realizar uma análise estatística dos quantitativos de RSU que os municípios goianos, via questionário, disseram gerar e compará-los com quantitativos obtidos em estudos realizados em municípios do estado. Os resultados da produção fornecida pelos municípios apontaram que quanto menores os municípios, maior a geração per capita de RSU, o que vai de encontro às pesquisas científicas, que mostram que quanto maior a população, maior a produção por pessoa. Para municípios de até 50 mil habitantes, há diferenças significativas entre a geração dos questionários e a geração teórica; já para municípios com mais de 50 mil habitantes, os valores não são significativamente diferentes. Os dados dos questionários relevaram, ainda, que não há correspondência entre a geração per capita de RSU e o número de habitantes, outro dado contrário ao que define a teoria. De qualquer modo, foi possível mensurar os quantitativos de RSU gerados pelos municípios goianos, o que auxiliará na decisão sobre as tecnologias mais adequadas para gerir os RSU de Goiás.

ABSTRACT The most suitable definition of a city's municipal solid waste (MSW) management system is mandatorily related to the amount of MSW generated. The state of Goiás faced such problem, since some of its municipalities had their MSW production data, but the state did not have an overall generation number. Considering this scenario, a questionnaire was sent to the municipalities of Goiás requesting information on their solid waste, among which was the MSW generation. The aim of this study was to conduct a statistical analysis of the MSW amount the state's municipalities have affirmed to generate, according to the questionnaires, and compare it with the quantitative data obtained in studies carried out in municipalities of the state. The results of the production provided by the municipalities have shown that the smaller the cities, the higher the generation of MSW per capita, a finding that goes against scientific research, which has proven that the larger the population, the higher the production per person. For municipalities with up to 50 thousand inhabitants, there are significant differences between the numbers presented in the questionnaires and those in the theoretical generation. On the other hand, municipalities with more than 50 thousand inhabitants don't have numbers so significantly different. The questionnaire data also revealed that there's no correspondence between the MSW generated per capita and the number of inhabitants, information contrary to what the theory states. However, it was still possible to measure the amount of MSW generated by Goiás cities, something that should be of great value to help decide the best technologies to the state's MSW management.