Statistical methods for identification of golden ratio.

Several biological systems such as the biomechanics of human heart, locomotion, and phyllotaxis of plants present a harmonic behavior because their fractal structure are associated to the golden ratio. The golden ratio (Φ = 1.618033988749…), also known as Phi, golden mean, golden section or divine proportion, is an irrational constant found in various forms in nature and recently has been used in many health areas. However, there is no literature on a specific statistical test to identify the golden ratio structures. To validate the results from each survey, it is necessary that statistical techniques be correctly selected and implemented, and the absence of a test to identify the golden ratio may undermines the scientific papers which have this goal. Since the golden number is a ratio, some tests have been wrongly applied in its identification. The objective of this paper is to present and to evaluate methods for identification of golden ratio. Four tests were evaluated: t-Student with ratio statistic (TR), with delta statistic (TΔ), with difference statistic (TED), and Wilcoxon test with statistic difference (WD). Data simulating different samples sizes (n = 2-200) and variability scenarios were used. The tests were assessed regarding type I error rate and power. For TΔ, type I error rate increased along with sample size and variability, achieving 50% in the scenario of relative standard deviation of 12.5% and 20.0% for line segments of lengths a and b, and sample size equal 200. This test also showed lower power when compared to the others in all scenarios. Similarly, for TR, the type I error rate was sensitive to the increasing in sample size, varying from 5 to 60%. On the other hand, WD and TED were associated to low type I error rates (around 5%) and high power (6.1% for sample size equal 2-100% for sample size equal 200). The TΔ and TR were inadequate to identify the golden ratio, since they did not controlled the type I error rate and/or presented low power, leading to possible erroneous conclusions. Therefore WD and TED, both with statistical of difference, appeared as the most appropriate methods to test golden ratio structures.

Characteristics and outcomes of patients with COVID-19 admitted to the ICU in a university hospital in São Paulo, Brazil - study protocol

OBJECTIVES: We designed a cohort study to describe characteristics and outcomes of patients with coronavirus disease (COVID-19) admitted to the intensive care unit (ICU) in the largest public hospital in Sao Paulo, Brazil, as Latin America becomes the epicenter of the pandemic. METHODS: This is the protocol for a study being conducted at an academic hospital in Brazil with 300 adult ICU beds dedicated to COVID-19 patients. We will include adult patients admitted to the ICU with suspected or confirmed COVID-19 during the study period. The main outcome is ICU survival at 28 days. Data will be collected prospectively and retrospectively by trained investigators from the hospital's electronic medical records, using an electronic data capture tool. We will collect data on demographics, comorbidities, severity of disease, and laboratorial test results at admission. Information on the need for advanced life support and ventilator parameters will be collected during ICU stay. Patients will be followed up for 28 days in the ICU and 60 days in the hospital. We will plot Kaplan-Meier curves to estimate ICU and hospital survival and perform survival analysis using the Cox proportional hazards model to identify the main risk factors for mortality. ClinicalTrials.gov: NCT04378582. RESULTS: We expect to include a large sample of patients with COVID-19 admitted to the ICU and to be able to provide data on admission characteristics, use of advanced life support, ICU survival at 28 days, and hospital survival at 60 days. CONCLUSIONS: This study will provide epidemiological data about critically ill patients with COVID-19 in Brazil, which could inform health policy and resource allocation in low- and middle-income countries.

Validade de medidas autorreferidas de massa e estatura e seu impacto na estimativa do estado nutricional pelo índice de massa corporal / Validity of self-reported measures of weight and height and its impact on nutritional status prediction by body mass index

Introdução: medidas autorreferidas de massa e estatura têm sido utilizadas para avaliação do estado nutricional em estudos epidemiológicos. Objetivo: verificar a validade da massa e da estatura autorreferidas, bem como do índice de massa corporal (IMC) obtido com estes valores. Método: participaram 395 homens e 549 mulheres . Os dados foram coletados entre estudantes da Universidade Santa Cecília - Santos. Todos os sujeitos referiam a sua massa e estatura, para a realização das medidas em seguida.Utilizou-se o teste t de Student para amostras dependentes para comparação das médias, a correlação linear de Pearson (r) e Coeficiente de Correlação Intraclasse (R) entre as duas formas de obtenção dos resultados. Resultados: os homens autorreferiram de forma válida tanto sua massa (p=0,125; r=0,963; R=0,912) quanto sua estatura (p=0,058; r=0,974; R=0,921), validando a avaliação do estado nutricional. Já as mulheres tenderam a subestimar sua massa corporal (p=0,000; r=0,882; R=0,888) e superestimar sua estatura (p=0,000; r=0,854; R=0,814), causando subestimativa no valor de IMC. Conclusão: para o grupo estudado não seria válido utilizar as medidas autorreferidas de massa e estatura das mulheres para estimativa do seu estado nutricional pelo índice de massa corporal.

Validade de medidas autorreferidas de massa e estatura e seu impacto na estimativa do estado nutricional pelo índice de massa corporal / Validity of self-reported measures of weight and height and its impact on nutritional status prediction by body mass index

Introdução: medidas autorreferidas de massa e estatura têm sido utilizadas para avaliação do estado nutricional em estudos epidemiológicos. Objetivo: verificar a validade da massa e da estatura autorreferidas, bem como do índice de massa corporal (IMC) obtido com estes valores. Método: participaram 395 homens e 549 mulheres . Os dados foram coletados entre estudantes da Universidade Santa Cecília - Santos. Todos os sujeitos referiam a sua massa e estatura, para a realização das medidas em seguida.Utilizou-se o teste t de Student para amostras dependentes para comparação das médias, a correlação linear de Pearson (r) e Coeficiente de Correlação Intraclasse (R) entre as duas formas de obtenção dos resultados. Resultados: os homens autorreferiram de forma válida tanto sua massa (p=0,125; r=0,963; R=0,912) quanto sua estatura (p=0,058; r=0,974; R=0,921), validando a avaliação do estado nutricional. Já as mulheres tenderam a subestimar sua massa corporal (p=0,000; r=0,882; R=0,888) e superestimar sua estatura (p=0,000; r=0,854; R=0,814), causando subestimativa no valor de IMC. Conclusão: para o grupo estudado não seria válido utilizar as medidas autorreferidas de massa e estatura das mulheres para estimativa do seu estado nutricional pelo índice de massa corporal.(AU)

INTRODUCTION: the nursing staff must inform parents with children suffering from congenital heart defects regarding their needs related to this situation. The most common needs are the seven, as follows: Information related to cardiopathy, promotion of physical activities, adequate diet, care with buccal health, prevention of infectious endocarditis, care during cyanosis crisis and drug administration. OBJECTIVE: to characterize how much information these parents have regarding this disorder. METHOD: systematic mapping on the literature in MEDLINE, Cochrane, CINAHL, LILACS and SciELO databases, from 1997 to 2007, obtaining 17 papers. RESULTS: the following needs, cyanosis crisis, promotion of physical activities and drug administration, were not adequately studied. The majority amongst the 17 papers was concentrated on the remaining four needs. Beside this, parent's knowledge is not satisfactory and is fragmented. It happens either in developed countries as well as in the underdeveloped ones. In general, care is performed by nurses, dental physicians and physicians. Training programs for parents are scarce and only one is described as successful. Changes are mandatory in terms of reorganization of services involving training and support for parents. Besides, validation of programs and protocols of care to promote training and development is required. These programs must be flexible to allow adaptation to clinical situation and to social, cultural and economic determinant factors acting on the family.(AU)