Modern Statistical Tendencies used in Investigations in the Medical Sciences / endencias estadísticas modernas utilizadas en investigaciones en las ciencias médicas

Introduction: The name Statistics was probably used in Egypt in 1549. The term Statistics, which was connected to the development of sovereign states, was coined in Germany in 1749 and used to designate the systematic collection of demographic and economic data by states. Objective: To present the most relevant and current statistical techniques in clinical medicine and epidemiology, as well as to show examples of the use of these techniques. Material and Methods: Review of the literature on the subject; presentation of some examples developed in class by professors of the subject Research Methodology and Statistics in Medical Sciences. Development: From the very beginnig, Statistics was used to characterize data based on their properties, as well as to develop information summary measures. In the modern era, procedures and techniques were designated to facilitate valid inferences to the universe from the sampling theory, whose foundation is the probability theory. Conclusions: There is a need for the application of modern techniques and especially the multivariate ones used to explain biological phenomena, which cannot be explained by one or two variables. This makes possible that our universities, scientific research centers, and companies conduct studies using statistical techniques that involve many variables, which are supposed to be related to the variable under study(AU)

Introducción: El nombre de Estadística probablemente se usó en Egipto en 1549. El término Estadística se acuñó en Alemania en 1749, conectado con el desarrollo de estados soberanos y designando la recopilación sistemática de datos demográficos y económicos por estados. Objetivo: Presentar las técnicas estadísticas más relevantes en el campo de la clínica médica y la epidemiología actualmente y mostrar ejemplos del uso de dichas técnicas. Material y métodos: Revisión de la literatura sobre el tema, algunos ejemplos desarrollados en clases por profesores de la asignatura Metodología de la investigación y Estadística en carreras de Ciencias Médicas. Desarrollo: En sus inicios la Estadística caracterizaba los datos basados en sus propiedades, desarrollaron medidas de resumen de información. En la era moderna se diseñaron procedimientos y técnicas para realizar inferencias válidas al universo a partir de la teoría del muestreo, cuyo fundamento es la teoría de probabilidades. Conclusiones: Necesidad de la aplicación de las técnicas modernas y especialmente las multivariadas para explicar los fenómenos biológicos, que no pueden ser explicados por una o dos variables, esto hace que nuestras universidades, centros de investigaciones científicas y empresas realicen sus estudios, utilizando técnicas estadísticas que envuelvan muchas variables que se suponen se relacionen con la variable objeto de estudio(AU)

Dependencia funcional y su relación con la mortalidad general en adultos mayores. México: 2001-2015 / Functional dependence and its relationship to general mortality in older adults. Mexico: 2001-2015

Resumen Objetivo: El objetivo de este artículo es estimar las probabilidades de transición entre los diversos grados de dependencia funcional, así como la capacidad predictiva de dicha dependencia para la mortalidad general de hombres y mujeres de 65 años y más residentes en México. Métodos: Mediante probabilidades se calculan transiciones entre diversos grados de dependencia funcional y, con modelos de riesgos proporcionales de Cox, se estiman los riesgos relativos de mortalidad. Resultados: Los resultados indican que las mujeres tienen mayores probabilidades de transitar de dependencia funcional ligera a moderada o severa que los hombres. Así mismo, las mujeres y los hombres con dependencia funcional severa, evaluada en la línea basal, tienen mayores riesgos relativos de mortalidad que los riesgos de mortalidad de los individuos sin dependencia funcional. Conclusión: Existen diferencias en las probabilidades de transición a la dependencia funcional, destacando que las mujeres muestran mayores probabilidades de transitar a mayores grados de restricciones físicas que los hombres. En este sentido, tener limitaciones físicas en el desarrollo de actividades básicas de la vida diaria incrementa los riesgos de mortalidad entre personas adultas mayores mexicanas.

Abstract Objective: The objective of this article is to estimate the probabilities of transition between different degrees of functional dependence, as well as the predictive capacity of this dependence for general mortality of women and men living in Mexico aged 65 and over. Methods: By means of probabilities, transitions between different degrees of functional dependence are calculated and, with proportional Cox risks models, the relative risks of mortality are estimated. Results: The results indicate that women are more likely to move from mild functional dependence to moderate or severe functional dependence than men. Likewise, women and men with severe functional dependence, assessed at the baseline, have higher relative risks of mortality than the mortality risks of individuals without functional dependence. Conclusion: There are differences in the probabilities of transition to functional dependence, noting that women are more likely to move to higher degrees of physical restraint than men. In this sense, having physical limitations in the development of basic activities of daily living increases mortality risks among Mexican elderly.

Estudo de rajadas de ventos e direções predominantes em Lavras, Minas Gerais, por meio da distribuição gama / Study of wind gust and its predominant directions in Lavras, Minas Gerais, Brazil, through gamma distribution

O presente trabalho foi conduzido com o objetivo de estudar as probabilidades de ocorrência de ventos extremos e suas direções predominantes para a região de Lavras, MG. Foram usados os dados registrados pelo anemógrafo universal da Estação Climatológica Principal de Lavras, situada no campus da Universidade Federal de Lavras. Com os dados disponíveis (139 meses), no período de janeiro de 1988 a maio de 2004, verificou-se o ajuste à distribuição Gama pelo teste de χ² a 5 por cento de probabilidade. Foram estimadas probabilidades de ocorrência de velocidades máximas diárias de vento iguais ou superiores a 10, 20, 30, 40, 50, 60, 70, 80, 90 e 100 km h-1, para cada mês. Verificou-se que os meses de setembro a fevereiro apresentaram ventos fortes, com probabilidades de ocorrência superiores as dos outros meses. Para ventos bastante fortes acima de 100 km h-1, as probabilidades de ocorrência são mínimas para todos os meses do ano. Quanto à direção para as rajadas de ventos, observou-se predominância das direções leste e oeste em relação às demais.

The present work was carried out in order to study the ccurrence probabilities o of extreme winds and their predominant directions in the region of Lavras, Minas Gerais state, Brazil. The data were collected from graphic registrations of the universal anemograph of the Principal Climatological Station of Lavras, located in the campus of the Federal University of Lavras. With the available data (139 months), in the period of January/1988 to May/2004, the adjustment by Gamma distribution was verified for this data series applying the χ² test to the 5 percent probability. Estimates of the occurrence probabilities of wind gust equal or above 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 km h-1 were determined for each month. It was verified that the months of September to February presented strong winds with probabilities higher than the other months. For very strong winds, above 100 km h-1, the occurrence probabilities were minimum for all months of the year. It was observed that the predominant wind gust direction were east and west in relation to the others.

Una conjetura metodológica acerca de la comprensión y la ejecución para un plan de Salud Pública / A methodologic conjecture about the understanding and the execution for a public health plan

Se plantea aquí una posición en la cual la Salud Pública es tomada como objeto de estudio, se recorre el problema natural de la gnoseología, cómo sufre con la ponderación de la corrupción como un elemento deletéreo, necesita de un marco jurídico efectivo que la sostenga, y tenga un objetivo inmerso en la teoría de Rawls y comprendido por el niño de 0 a 5 años con su madre.

Its considers here a position in which, the Public Health, as study object, crosses the natual problem of the gnoseology, it suffers with the ponderation of the corruption like a harmful element, it needs an effective legal frame that maintains it, as well as an objective immersed in Rawls’ theory, and understood by any child of 0 to 5 years with his mother.

Avaliação de métodos de estimação intervalar para funções lineares binomiais via bootstrap infinito / Evaluation of intervalar estimation methods for binomial linear functions through infinity bootstrap

Objetivou-se, neste trabalho, avaliar intervalos de confiança de diferentes funções lineares compostas por proporções binomiais construídas com base no método de Wald e Wald ajustado utilizando a técnica de bootstrap infinito. Considerados diversos tamanhos amostrais (n is), parâmetros (p) e número de coeficientes das funções lineares. Concluiu-se, por meio das probabilidades de cobertura dos intervalos de confiança das populações binomiais, cujas proporções foram baixas (p=0,2) e considerando diferentes tamanhos de amostras, que a generalização bootstrap do método de Wald ajustado foi eficiente para funções lineares cujos coeficientes indicaram a comparação de uma proporção versus as demais.

This work aimed to evaluate confidence intervals of different linear functions of binomial proportions base on Wald and Wald's adjusted method using the infinity bootstrap technique. Several sample sizes (n i), binomial parameters (p) and number of coefficients of the linear functions were considered. One concluded through the probabilities of binomial population confidence covered intervals that the bootstrap generalization of adjusted Wald's method was efficient for linear functions whose coefficients indicated a comparison of versus the others proportion (p=0.2) considering different sample sizes.

Development of Conformal Radiotherapy with Respiratory Gate Device / 대한방사선종양학회지

PURPOSE: 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. MATERIALS AND METHODS: The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were performed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. RESULTS: The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probability. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values (4-5% increased) for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased (60-70% increased) for upon extending PTV margins by 2.0 cm. CONCLUSION: Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.

Estatísticas dos resultados das análises de laboratório de solo / Statistical analysis of a soil testing laboratory results

O presente trabalho teve como objetivos estudar as estatísticas dos valores analíticos das análises de solo realizadas no Laboratório de Análise de Solos da Universidade Federal de Santa Maria (LAS/UFSM) durante o período de 1988 à 1993 e obter valores como limites críticos que possibilitem um controle de qualidade na emissão dos laudos das análises de solo. Foram utilizadas as 21380 amostras de solos, provenientes de 162 municípios do Rio Grande do Sul. As análises estatísticas/oram realizadas para os 29 municípios que enviaram mais de 150 amostras de solo. Uma evolução distinta dos valores do teor de argila, pH em água, índice SMP, fósforo, potássio, teor de matéria orgânica, alumínio trocável e cálcio + magnésio trocável foi obtida nos diferentes municípios em função do tempo. As estatísticas obtidas, para estas variáveis, podem ser usadas para caracterizar a fertilidade dos solos destes municípios. Os resultados são dispersos e, em geral, não seguem uma distribuição de probabilidades conhecida. Os limites críticos (inferior e superior) obtidos podem ser usados como parâmetros para o controle de qualidade nos laudos de análise de solo.

The objectives of this research were to study the behaviour and evolution of soil testing results from 1988 to 1993 time period and to define the range for critical values to include in algorithms which may be used for soil testing reports. Results of 21380 soil samples analysis from Federal University of Santa Maria soil testing laboratory were used from 1988 to 1993 time period. The samples carne from 162 counties of Rio Grande do Sul state including 29 counties with more then 150 soil samples. The results for clay content, water pH, SMP Índex, P, K, organic matter and exchangeable Al and Ca+Mg for each county are dispersed and show unknown distribution probabilities. Higher and lower critical values were obteined to analyze quality control for routine soil testing labs.