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1.
Rev Bras Epidemiol ; 22Suppl 1(Suppl 1): e190002, 2019.
Artigo em Inglês, Português | MEDLINE | ID: mdl-31576978

RESUMO

INTRODUCTION: Respondent-Driven Sampling (RDS) has been used in surveys with key populations at risk of HIV infection, such as female sex workers (FSW). This article describes the application of the RDS method among FSW in 12 Brazilian cities, during a survey carried out in 2016. METHODOLOGY: A biological and behavioral surveillance study carried out in 12 Brazilian cities, with a minimum sample of 350 FSW in each city. Tests were performed for HIV, syphilis, and hepatitis B and C infections. A social-behavioral questionnaire was also applied. RESULTS: The sample was comprised of 4,328 FSW. For data analysis, the sample was weighted according to each participant's network size (due consideration to the implications of RDS complex design and to the effects of homophilia are recommended). DISCUSSION: Although RDS methods for obtaining a statistical sample are based on strong statistical assumptions, allowing for an estimation of statistical parameters, with each new application the method has been rethought. In the analysis of whole-sample data, estimators were robust and compatible with those found in 2009. However, there were significant variations according to each city. CONCLUSION: The achieved sample size was of great relevance for assessing progress and identifying problems regarding the prevention and treatment of Sexually Transmitted Infections. New RDS studies with more time and operational resources should be envisaged. This could further network development.


Assuntos
Infecções por HIV/epidemiologia , Inquéritos Epidemiológicos/métodos , Hepatite C/epidemiologia , Vigilância da População/métodos , Profissionais do Sexo/estatística & dados numéricos , Sífilis/epidemiologia , Brasil/epidemiologia , Cidades , Feminino , Humanos , Fatores de Risco , Tamanho da Amostra , Amostragem , Inquéritos e Questionários
2.
Medicine (Baltimore) ; 98(43): e17630, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31651877

RESUMO

BACKGROUND: The randomized controlled trial (RCT) is the gold-standard research design in biomedicine. However, practical concerns often limit the sample size, n, the number of patients in a RCT. We aim to show that the power of a RCT can be increased by increasing p, the number of baseline covariates (sex, age, socio-demographic, genomic, and clinical profiles et al, of the patients) collected in the RCT (referred to as the 'dimension'). METHODS: The conventional test for treatment effects is based on testing the 'crude null' that the outcomes of the subjects are of no difference between the two arms of a RCT. We propose a 'high-dimensional test' which is based on testing the 'sharp null' that the experimental intervention has no treatment effect whatsoever, for patients of any covariate profile. RESULTS: Using computer simulations, we show that the high-dimensional test can become very powerful in detecting treatment effects for very large p, but not so for small or moderate p. Using a real dataset, we demonstrate that the P value of the high-dimensional test decreases as the number of baseline covariates increases, though it is still not significant. CONCLUSION: In this big-data era, pushing p of a RCT to the millions, billions, or even trillions may someday become feasible. And the high-dimensional test proposed in this study can become very powerful in detecting treatment effects.


Assuntos
Big Data , Avaliação de Resultados (Cuidados de Saúde)/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Simulação por Computador , Interpretação Estatística de Dados , Humanos , Tamanho da Amostra
3.
Can Assoc Radiol J ; 70(4): 344-353, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31522841

RESUMO

PURPOSE: The required training sample size for a particular machine learning (ML) model applied to medical imaging data is often unknown. The purpose of this study was to provide a descriptive review of current sample-size determination methodologies in ML applied to medical imaging and to propose recommendations for future work in the field. METHODS: We conducted a systematic literature search of articles using Medline and Embase with keywords including "machine learning," "image," and "sample size." The search included articles published between 1946 and 2018. Data regarding the ML task, sample size, and train-test pipeline were collected. RESULTS: A total of 167 articles were identified, of which 22 were included for qualitative analysis. There were only 4 studies that discussed sample-size determination methodologies, and 18 that tested the effect of sample size on model performance as part of an exploratory analysis. The observed methods could be categorized as pre hoc model-based approaches, which relied on features of the algorithm, or post hoc curve-fitting approaches requiring empirical testing to model and extrapolate algorithm performance as a function of sample size. Between studies, we observed great variability in performance testing procedures used for curve-fitting, model assessment methods, and reporting of confidence in sample sizes. CONCLUSIONS: Our study highlights the scarcity of research in training set size determination methodologies applied to ML in medical imaging, emphasizes the need to standardize current reporting practices, and guides future work in development and streamlining of pre hoc and post hoc sample size approaches.


Assuntos
Pesquisa Biomédica , Diagnóstico por Imagem/estatística & dados numéricos , Aprendizado de Máquina , Humanos , Tamanho da Amostra
4.
BMC Bioinformatics ; 20(1): 437, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438848

RESUMO

BACKGROUND: Batch effects were not accounted for in most of the studies of computational drug repositioning based on gene expression signatures. It is unknown how batch effect removal methods impact the results of signature-based drug repositioning. Herein, we conducted differential analyses on the Connectivity Map (CMAP) database using several batch effect correction methods to evaluate the influence of batch effect correction methods on computational drug repositioning using microarray data and compare several batch effect correction methods. RESULTS: Differences in average signature size were observed with different methods applied. The gene signatures identified by the Latent Effect Adjustment after Primary Projection (LEAPP) method and the methods fitted with Linear Models for Microarray Data (limma) software demonstrated little agreement. The external validity of the gene signatures was evaluated by connectivity mapping between the CMAP database and the Library of Integrated Network-based Cellular Signatures (LINCS) database. The results of connectivity mapping indicate that the genes identified were not reliable for drugs with total sample size (drug + control samples) smaller than 40, irrespective of the batch effect correction method applied. With total sample size larger than 40, the methods correcting for batch effects produced significantly better results than the method with no batch effect correction. In a simulation study, the power was generally low for simulated data with sample size smaller than 40. We observed best performance when using the limma method correcting for two principal components. CONCLUSION: Batch effect correction methods strongly impact differential gene expression analysis when the sample size is large enough to contain sufficient information and thus the downstream drug repositioning. We recommend including two or three principal components as covariates in fitting models with limma when sample size is sufficient (larger than 40 drug and controls combined).


Assuntos
Biologia Computacional/métodos , Preparações Farmacêuticas/metabolismo , Transcriptoma , Simulação por Computador , Bases de Dados Factuais , Reposicionamento de Medicamentos , Humanos , Análise de Componente Principal , Tamanho da Amostra
5.
Prensa méd. argent ; 105(6): 361-369, Jul 2019. graf, tab
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-1023787

RESUMO

Influenza is a respiratory disease ocasionated by influenza virus A and B. Is a disease with high morbi-mortality world-wide. Influenza produces an acute febrile respiratory illness with cough, headache and myalgias for 3-4 days, with simptoms that may persist for as long as 2 weeks. There are three types of influenza virsuses: A, B and C, of whom the type a has a higher ability to originate pandemias and is subclassified according to their surface antigens: hemaglutinine (H) and neuraminidase (N). Of the capacity of mutation that has the influenza virus and the consequent expression of different proteins, can modify its virulence. The transmission route is through direct contact with secretetory repirations. The transmission route is through direct contact with secretetory repirations. The incubation period is scant, between 12-72 hs. The aim of this study was to compare the clinical characteristics demographicals and evolutive of pediatric patients hospitalized because by Influenze A: subtypes H1N1 (pdm2009) and H3N2. An observative study was performed, retrospective, using data of hospitalizations of children during the years 2016 and 2017 with influenza A confirmed by laboratory. The study also, aimed to evaluate if the viral subtype constitutes a factor of risk, independent for complicated hospitalization (admission to intensive care and/or development of complications) in hospitalized children. The results obtained in the study are detailed in the paper. In conclusion, both viral subtypes affected mainly to children with risk factors. The viral subtype H1N1 was related with higher severety in hospitalized children. is of most importance to perform preventive works, specially in vulnerable groups, offering a good cover of immunizations. The clinical parameters arae commented (AU)


Assuntos
Humanos , Criança , Comorbidade/tendências , Fatores Epidemiológicos , Análise Estatística , Estudos Retrospectivos , Estudos de Coortes , Tamanho da Amostra , Seleção de Pacientes , Vírus da Influenza A Subtipo H1N1/patogenicidade , Vírus da Influenza A Subtipo H3N2/patogenicidade , Influenza Aviária/complicações , Fatores de Risco
6.
BMC Evol Biol ; 19(1): 117, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182024

RESUMO

BACKGROUND: The branchiostegal series consists of an alignment of bony elements in the posterior portion of the skull of osteichthyan vertebrates. We trace the evolution of the number of elements in a comprehensive survey that includes 440 extant and 66 extinct species. Using a newly updated actinopterygian tree in combination with phylogenetic comparative analyses, we test whether osteichthyan branchiostegals follow an evolutionary trend under 'Williston's law', which postulates that osteichthyan lineages experienced a reduction of bony elements over time. RESULTS: We detected no overall macroevolutionary trend in branchiostegal numbers, providing no support for 'Williston's law'. This result is robust to the subsampling of palaeontological data, but the estimation of the model parameters is much more ambiguous. CONCLUSIONS: We find substantial evidence for a macroevolutionary dynamic favouring an 'early burst' of trait evolution over alternative models. Our study highlights the challenges of accurately reconstructing macroevolutionary dynamics even with large amounts of data about extant and extinct taxa.


Assuntos
Evolução Biológica , Extinção Biológica , Fósseis , Vertebrados/anatomia & histologia , Animais , Biodiversidade , Modelos Teóricos , Filogenia , Tamanho da Amostra , Crânio/anatomia & histologia , Fatores de Tempo
7.
Ecol Appl ; 29(6): e01947, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31183944

RESUMO

Telemetry is a key, widely used tool to understand marine megafauna distribution, habitat use, behavior, and physiology; however, a critical question remains: "How many animals should be tracked to acquire meaningful data sets?" This question has wide-ranging implications including considerations of statistical power, animal ethics, logistics, and cost. While power analyses can inform sample sizes needed for statistical significance, they require some initial data inputs that are often unavailable. To inform the planning of telemetry and biologging studies of marine megafauna where few or no data are available or where resources are limited, we reviewed the types of information that have been obtained in previously published studies using different sample sizes. We considered sample sizes from one to >100 individuals and synthesized empirical findings, detailing the information that can be gathered with increasing sample sizes. We complement this review with simulations, using real data, to show the impact of sample size when trying to address various research questions in movement ecology of marine megafauna. We also highlight the value of collaborative, synthetic studies to enhance sample sizes and broaden the range, scale, and scope of questions that can be answered.


Assuntos
Ecologia , Ecossistema , Animais , Tamanho da Amostra , Telemetria
8.
BMC Bioinformatics ; 20(Suppl 11): 275, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31167661

RESUMO

BACKGROUND: The advent of single cell RNA sequencing (scRNA-seq) enabled researchers to study transcriptomic activity within individual cells and identify inherent cell types in the sample. Although numerous computational tools have been developed to analyze single cell transcriptomes, there are no published studies and analytical packages available to guide experimental design and to devise suitable analysis procedure for cell type identification. RESULTS: We have developed an empirical methodology to address this important gap in single cell experimental design and analysis into an easy-to-use tool called SCEED (Single Cell Empirical Experimental Design and analysis). With SCEED, user can choose a variety of combinations of tools for analysis, conduct performance analysis of analytical procedures and choose the best procedure, and estimate sample size (number of cells to be profiled) required for a given analytical procedure at varying levels of cell type rarity and other experimental parameters. Using SCEED, we examined 3 single cell algorithms using 48 simulated single cell datasets that were generated for varying number of cell types and their proportions, number of genes expressed per cell, number of marker genes and their fold change, and number of single cells successfully profiled in the experiment. CONCLUSIONS: Based on our study, we found that when marker genes are expressed at fold change of 4 or more, either Seurat or SIMLR algorithm can be used to analyze single cell dataset for any number of single cells isolated (minimum 1000 single cells were tested). However, when marker genes are expected to be only up to fold change of 2, choice of the single cell algorithm is dependent on the number of single cells isolated and rarity of cell types to be identified. In conclusion, our work allows the assessment of various single cell methods and also aids in the design of single cell experiments.


Assuntos
Biologia Computacional/métodos , Projetos de Pesquisa , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Algoritmos , Simulação por Computador , Bases de Dados Genéticas , Perfilação da Expressão Gênica/métodos , Humanos , Tamanho da Amostra
10.
J Dairy Sci ; 102(8): 6987-6999, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31229283

RESUMO

Accurate and precise determinations of fiber digestibility are essential for proper diet formulation for dairy cows. Our objectives were 3-fold: (1) regress in vitro neutral detergent fiber digestibility (NDFD) values from 48 triticale forages determined at multiple endpoints ranging from 12 to 240 h with Ankom DaisyII Incubator system (Ankom Technology Corp., Macedon, NY) methods using 0.25- or 0.50-g sample sizes on concentrations of fiber-related analytes or growth stage; (2) directly compare NDFD values determined with 0.25- or 0.50-g sample sizes by Ankom methods after 12-, 24-, 30-, 48-, 144-, or 240-h incubations; and (3) compare NDFD values determined by Ankom methods after 30 and 48 h of incubation with those determined by traditional sealed-tube procedures obtained from a commercial laboratory. Generally, plant growth stage, which was quantified with a linear model suitable for serving as an independent regression variable, proved to be a better predictor variable for NDFD than neutral detergent fiber or acid detergent lignin. For direct comparisons of 0.25- and 0.50-g sample sizes using Ankom methods, the regression relationship for a 30-h incubation was explained by a linear model [Y = 1.206x - 1.1; coefficient of determination (R2) = 0.933], in which the slope differed from unity, but the intercept did not differ from 0. After a 48-h incubation, a linear model (Y = 1.014x + 7.1; R2 = 0.964) indicated that the slope did not differ from unity, but the intercept was >0. A linear regression (Y = 1.040x - 1.8; R2 = 0.861) of the 30-h incubation results obtained by Ankom methods using the 0.25-g sample size on those from the commercial laboratory indicated the slope and intercept did not differ from unity or 0, respectively. A similar relationship was obtained from the 48-h incubation (Y = 1.021x - 3.4; R2 = 0.866). Relationships were poorer when the 0.50-g sample size was used by Ankom methods, particularly for the 30-h incubation, where the slope (0.824) was less than unity. Generally, NDFD values were greater for the 0.25-g sample size by Ankom methods, especially with 24-, 30-, and 48-h incubation times, and agreement with traditional sealed-tube methods was improved with the smaller sample size. Synchronization of results between Ankom and traditional methods needs to be further verified across a wider range of forages and harvest/preservation methods before definitive recommendations can be made.


Assuntos
Ração Animal/análise , Bovinos/fisiologia , Fibras na Dieta/metabolismo , Triticale , Animais , Reatores Biológicos/veterinária , Indústria de Laticínios , Dieta/veterinária , Digestão , Feminino , Lignina/metabolismo , Folhas de Planta , Tamanho da Amostra
11.
Undersea Hyperb Med ; 46(1): 45-53, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31154684

RESUMO

Background: Perianal fistulizing Crohn's disease (pCD) has a significant impact on patients' health and quality of life. Current treatment options have a relatively low success rate and a high recurrence risk. Positive effects of hyperbaric oxygen (HBO2) therapy have been indicated in animal studies as well as in small case series. Methods/Design: This is a non-randomized, controlled pilot study. A total of 20 patients with pCD who have been refractory to standard therapy for at least six months will be included. Patients with a seton and stable treatment regimen will be included. Patients with anal strictures, rectovaginal fistulas, stoma or deep ulceration of the rectum will be excluded. Patients who are eligible but refuse HBO2 will be asked to serve as controls. Patients in the HBO2 group will be treated with 40 sessions of HBO2 therapy at 243-253 kPa, with the seton being removed after 30 sessions. Co-primary endpoints are changes in the perianal disease activity index and MRI-scores. Secondary outcomes are fistula drainage assessment, laboratory findings and patient-reported outcomes. Assessment will be done at baseline, 16 weeks, 34 weeks and 60 weeks after finishing HBO2. Discussion: The aim of this study is to investigate the feasibility and therapeutic effect of HBO2 on pCD. The one-year follow-up should provide information on the effect durability. A comparison between patients treated with HBO2 and patients who continue to receive standard care will be made. The risk of bias will be limited by using clearly defined inclusion and exclusion criteria, baseline characteristics and consecutive recruitment of patients through an outpatient fistula clinic. Trial registration: The HOT-TOPIC trial has been approved by the local Medical Ethical Committee of the Academic Medical Centre in Amsterdam, the Netherlands. The trial has been registered at the Netherlands Trial Register (www.trialregister.nl), registration number: NTR 6676. Protocol version: August 2017, version 3.0.


Assuntos
Ensaios Clínicos Controlados como Assunto , Doença de Crohn/complicações , Oxigenação Hiperbárica , Fístula Retal/terapia , Estudos de Viabilidade , Seguimentos , Humanos , Projetos Piloto , Estudos Prospectivos , Fístula Retal/etiologia , Tamanho da Amostra , Fatores de Tempo
13.
Genet Sel Evol ; 51(1): 24, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31146682

RESUMO

BACKGROUND: In settings with social interactions, the phenotype of an individual is affected by the direct genetic effect (DGE) of the individual itself and by indirect genetic effects (IGE) of its group mates. In the presence of IGE, heritable variance and response to selection depend on size of the interaction group (group size), which can be modelled via a 'dilution' parameter (d) that measures the magnitude of IGE as a function of group size. However, little is known about the estimability of d and the precision of its estimate. Our aim was to investigate how precisely d can be estimated and what determines this precision. METHODS: We simulated data with different group sizes and estimated d using a mixed model that included IGE and d. Schemes included various average group sizes (4, 6, and 8), variation in group size (coefficient of variation (CV) ranging from 0.125 to 1.010), and three values of d (0, 0.5, and 1). A design in which individuals were randomly allocated to groups was used for all schemes and a design with two families per group was used for some schemes. Parameters were estimated using restricted maximum likelihood (REML). Bias and precision of estimates were used to assess their statistical quality. RESULTS: The dilution parameter of IGE can be estimated for simulated data with variation in group size. For all schemes, the length of confidence intervals ranged from 0.114 to 0.927 for d, from 0.149 to 0.198 for variance of DGE, from 0.011 to 0.086 for variance of IGE, and from 0.310 to 0.557 for genetic correlation between DGE and IGE. To estimate d, schemes with groups composed of two families performed slightly better than schemes with randomly composed groups. CONCLUSIONS: Dilution of IGE was estimable, and in general its estimation was more precise when CV of group size was larger. All estimated parameters were unbiased. Estimation of dilution of IGE allows the contribution of direct and indirect variance components to heritable variance to be quantified in relation to group size and, thus, it could improve prediction of the expected response to selection in environments with group sizes that differ from the average size.


Assuntos
Variação Genética , Gado/genética , Modelos Genéticos , Animais , Feminino , Masculino , Fenótipo , Tamanho da Amostra , Seleção Genética , Comportamento Social
14.
Acta colomb. psicol ; 22(1): 202-215, ene.-jun. 2019. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-989081

RESUMO

Resumen En el presente trabajo se evaluó el efecto de distintos tipos de entrenamiento sobre (a) la ejecución en pruebas de aprendizaje y transferencia, y (b) la elaboración de descripciones poscontacto en una tarea de discriminación condicional de segundo orden. Con este fin, se asignaron 16 participantes a cuatro grupos; la fase de entrenamiento para los grupos 1 y 3 consistió en la observación de una tarea de discriminación condicional de segundo orden en la que las respuestas de igualación fueron resaltadas con un marco rojo y se indicó, para cada ensayo, si eran acertadas o erróneas (entrenamiento observacional), mientras que para los participantes de los grupos 2 y 4 la tarea consistió en emitir una respuesta explícita de igualación ensayo por ensayo (entrenamiento instrumental). Adicionalmente, se le pidió a los participantes de los grupos 3 y 4 que realizaran una descripción de las contingencias enfrentadas cada doce ensayos, y al finalizar la tarea completa se le pidió a todos los participantes que elaboraran una descripción similar. Como resultado, los participantes de los grupos que estuvieron bajo entrenamiento observacional presentaron el mayor porcentaje de aciertos en las pruebas de aprendizaje y transferencia, además de que elaboraron descripciones poscontacto más específicas y pertinentes que los individuos de los grupos restantes. Estos resultados sugieren que el aprendizaje mediante la observación puede darse incluso si el observador no es expuesto directamente a la ejecución de la respuesta de otro individuo, es decir, aun cuando las respuestas reforzadas se presenten solo de manera gráfica.


Resumo Neste trabalho, foi avaliado o efeito de diferentes tipos de treinamento sobre a execução em testes de aprendizagem e transferência e a elaboração de descrições pós-contato numa tarefa de discriminação condicional de segunda ordem. Com esse objetivo, foram designados 16 participantes a quatro grupos. A fase de treinamento para os participantes dos grupos 1 e 3 consistiu na observação de uma tarefa de discriminação condicional de segunda ordem na qual as respostas de igualação foram ressaltadas com um sinal vermelho e foi indicado, para cada ensaio, se eram acertadas ou errôneas (treinamento observacional). Nessa mesma fase, para os participantes dos grupos 2 e 4, a tarefa consistiu em emitir uma resposta explícita de igualação ensaio por ensaio (treinamento instrumental). Além disso, foi pedido aos participantes dos grupos 3 e 4 que realizassem uma descrição das contingências enfrentadas a cada doze ensaios. Ao finalizar a tarefa, foi solicitado a todos os participantes que elaborassem uma descrição semelhante. Como resultado, os participantes dos grupos que estiveram sob o treinamento observacional apresentaram maior porcentagem de acertos nos testes de aprendizagem e transferência, e elaboraram descrições pós-contato mais específicas e pertinentes do que os indivíduos dos demais grupos. Esses resultados sugerem que a aprendizagem mediante a observação pode acontecer inclusive se o observador não for exposto diretamente à execução da resposta de outro indivíduo, isto é, ainda quando as respostas reforçadas forem apresentadas somente de maneira gráfica.


Abstract The effects of different types of training over a) performance on learning and transfer tasks, and b) generation of post-contact descriptions in a second order matching-to-sample task were assessed. 16 participants were randomly assigned to one of four experimental groups. During the training phase, the requirement for participants in groups 1 and 3 consisted of the observation of a conditional discrimination task in which matching responses were highlighted with a red frame and indicated, for each trial, whether they were right or wrong (observational training). During this same phase, the task for participants in groups 2 and 4 was to produce, trial by trial, an explicit matching response (instrumental training). Additionally, participants in groups 3 and 4 were required to write a description of the contingencies every twelve trials. After the task, all participants were requested to develop a similar description. Participants of groups that were under observational training had the highest percentage of correct answers on learning and transfer tests. Similarly, they produced more specific rules than individuals from other groups. These results suggest that learning by observation can occur even if the viewer is not directly exposed to responses of another individual, that is, even when reinforced responses are simply presented graphically.


Assuntos
Humanos , Masculino , Feminino , Testes Psicológicos , Tamanho da Amostra , Capacitação
15.
Acta colomb. psicol ; 22(1): 248-260, ene.-jun. 2019. tab
Artigo em Espanhol | LILACS | ID: biblio-989083

RESUMO

Resumen En los últimos años se han desarrollado medidas breves de los cinco factores de personalidad, sin embargo, la ganancia práctica de tiempo provista por las formas breves puede implicar propiedades psicométricas más débiles de los instrumentos. En la construcción de escalas breves, para mantener propiedades psicométricas adecuadas se debe emplear criterios teóricos y empíricos en la selección de los ítems y minimizar los sesgos de respuesta, como el de la aquiescencia (AC), que hace referencia a la tendencia de las personas a estar de acuerdo con afirmaciones positivas independientemente del contenido de la afirmación. Teniendo esto en cuenta, el objetivo principal del presente estudio fue desarrollar un instrumento breve (30 ítems), de dominio público, para medir los cinco factores de personalidad en población latina, controlando el sesgo de respuesta AC. La muestra estuvo compuesta por 910 participantes, 543 de sexo femenino (59.6 %) y 367 de sexo masculino (40.3 %), con edades comprendidas entre los 15 y los 80 años (M = 29.52; DT = 12.25), pertenecientes a la ciudad de Córdoba, Argentina. Para el proceso de validación se propuso realizar un estudio de convergencia con las cinco escalas del NEO-FFI, un análisis de diferencia de grupos según el sexo y la edad de los participantes, y un estudio de validez predictiva respecto a algunas actividades recreacionales (uso de drogas, irresponsabilidad, amistad, erudición/creatividad y comunicación). Los resultados indican que el IPIP-R-30 presenta una estructura factorial de cinco factores, índices de confiabilidad adecuados tanto de consistencia interna como de estabilidad temporal, evidencia de validez convergente con las escalas del NEO-FFI, evidencia de diferencia de grupos según sexo y edad, y validez predictiva de la frecuencia de diferentes categorías de actividades específicas. De esta manera, se puede concluir que el IPIP-R-30 constituye una herramienta válida de evaluación de los rasgos de personalidad en nuestro medio, con puntuaciones libres del sesgo de AC.


Resumo Nos últimos anos, têm sido desenvolvidas medidas breves dos cinco fatores de personalidade; contudo, o ganho prático de tempo previsto pelas formas breves pode implicar propriedades psicométricas mais fracas dos instrumentos. Na construção de escalas breves, para manter propriedades psicométricas adequadas, devem ser empregados critérios teóricos e empíricos na seleção dos itens, e devem ser minimizados os vieses de resposta, como o da aquiescência (AC). Esse conceito faz referência à tendência das pessoas que estão de acordo com afirmações positivas, independentemente do conteúdo da afirmação. Nesse sentido, o objetivo principal deste estudo foi desenvolver um instrumento breve (30 itens), de domínio público, para medir os cinco fatores de personalidade em população latina, controlando o viés de resposta AC. A amostra esteve composta por 910 participantes, 543 de sexo feminino (59.6 %) e 367 de sexo masculino (40.3 %), entre 15 e 80 anos de idade (M = 29.52; DP = 12.25), pertencentes à cidade de Córdoba, Argentina. Para o processo de validação, foi proposto realizar um estudo de convergência com as cinco escalas do NEO-FFI, uma análise de diferença de grupos segundo o sexo e idade dos participantes, e um estudo de validade preditiva a respeito de atividades recreativas (uso de drogas, irresponsabilidade, amizade, erudição/ criatividade e comunicação). Os resultados indicam que o IPIP-R-30 apresenta uma estrutura fatorial de cinco fatores, índices de confiabilidade adequados tanto de consistência interna quanto de estabilidade temporal, evidência de validade convergente com as escalas do NEO-FFI, evidência de diferença de grupos segundo sexo e idade, e validade preditiva da frequência de diferentes categorias de atividades específicas. Dessa maneira, pode-se concluir que o IPIP-R-30 constitui uma ferramenta válida de avaliação dos traços de personalidade em nosso meio, com pontuações livros do viés de AC.


Abstract In recent years, brief measures of the five personality factors have been developed; however, the practical gain of time provided by the brief versions may imply weaker psychometric properties of the instruments. To maintain adequate psychometric properties in the construction of brief scales, theoretical and empirical criteria should be used in the selection of items, and response biases such as acquiescence (AC) should be minimized. The term AC refers to people's tendency to agree with positive statements, regardless of their content. The main purpose of the present study is to develop a brief public domain instrument (30 items) to measure the five personality factors in the Latin American population, controlling the AC response bias. The sample consisted of 910 participants, 543 women (59.6 %) and 367 men (40.3 %), age range 15-80 years (M = 29.52; DT = 12.25) from the city of Córdoba, Argentina. For the validation process, a convergence study with the five NEO-FFI scales, an analysis of group differences according to the participants' sex and age, and a predictive validity study regarding recreational activities (drug use, irresponsibility, friendship, erudition/creativity, and communication) were performed. The results indicate that the IPIP-R-30 presents a five-factor factorial structure, adequate reliability indices of both internal consistency and temporal stability, evidence of convergent validity with the NEO-FFI scales, evidence of group differences as regards sex and age, and frequency predictive validity of different categories of specific activities. Thus, it can be concluded that the IPP-R-30 is a valid tool for assessing personality factors in our environment, with scores free of AC bias.


Assuntos
Humanos , Masculino , Feminino , Personalidade , Testes Psicológicos , Tamanho da Amostra
16.
Anticancer Res ; 39(6): 2711-2714, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31177105

RESUMO

Perioperative oral/dental care has been introduced to cancer surgery patients as perioperative management using a multimodal approach. Several approaches were tested for managing perioperative oral/dental health care in this population. However, while the clinical impact of perioperative oral/dental care on patients with various types of malignancies has been evaluated, most previous studies have used and evaluated data obtained from relatively small sample sizes of fewer than 200 patients from individual institutions. Therefore, the recommendation of perioperative oral/dental care is controversial. Recent studies have shown that perioperative oral/dental care affects the cancer surgery outcomes. In addition, perioperative oral/dental care by dentistry professionals and the number of oral/dental care sessions have been shown to be important for this beneficial effect, even when patients were temporarily intubated. Further studies are, therefore, necessary to establish the optimal perioperative dental/oral care regiment and verify the beneficial effect of perioperative oral/dental care on cancer surgery outcomes. This review summarizes the background, current status, and future perspectives of perioperative oral/dental care for cancer surgery.


Assuntos
Assistência Odontológica/métodos , Neoplasias/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Feminino , Humanos , Masculino , Assistência Perioperatória , Tamanho da Amostra , Resultado do Tratamento
18.
BMC Bioinformatics ; 20(1): 266, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31138108

RESUMO

BACKGROUND: There are over 25 tools dedicated for the detection of Copy Number Variants (CNVs) using Whole Exome Sequencing (WES) data based on read depth analysis. The tools reported consist of several steps, including: (i) calculation of read depth for each sequencing target, (ii) normalization, (iii) segmentation and (iv) actual CNV calling. The essential aspect of the entire process is the normalization stage, in which systematic errors and biases are removed and the reference sample set is used to increase the signal-to-noise ratio. Although some CNV calling tools use dedicated algorithms to obtain the optimal reference sample set, most of the advanced CNV callers do not include this feature. To our knowledge, this work is the first attempt to assess the impact of reference sample set selection on CNV detection performance. METHODS: We used WES data from the 1000 Genomes project to evaluate the impact of various methods of reference sample set selection on CNV calling performance of three chosen state-of-the-art tools: CODEX, CNVkit and exomeCopy. Two naive solutions (all samples as reference set and random selection) as well as two clustering methods (k-means and k nearest neighbours (kNN) with a variable number of clusters or group sizes) have been evaluated to discover the best performing sample selection method. RESULTS AND CONCLUSIONS: The performed experiments have shown that the appropriate selection of the reference sample set may greatly improve the CNV detection rate. In particular, we found that smart reduction of reference sample size may significantly increase the algorithms' precision while having negligible negative effect on sensitivity. We observed that a complete CNV calling process with the k-means algorithm as the selection method has significantly better time complexity than kNN-based solution.


Assuntos
Algoritmos , Variações do Número de Cópias de DNA/genética , Benchmarking , Bases de Dados Genéticas , Feminino , Humanos , Masculino , Padrões de Referência , Tamanho da Amostra
19.
J Appl Meas ; 20(2): 154-166, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31120433

RESUMO

This simulation study explores the effects of missing data mechanisms, proportions of missing data, sample size, and test length on the biases and standard errors of item parameters using the Rasch measurement model. When responses were missing completely at random (MCAR) or missing at random (MAR), item parameters were unbiased. When responses were missing not at random (MNAR), item parameters were severely biased, especially when the proportion of missing responses was high. Standard errors were primarily affected by sample size, with larger samples associated with smaller standard errors. Standard errors were inflated in MCAR and MAR conditions, while MNAR standard errors were similar to what they would have been, had the data been complete. This paper supports the conclusion that the Rasch model can handle varying amounts of missing data, provided that the missing responses are not MNAR.


Assuntos
Interpretação Estatística de Dados , Modelos Estatísticos , Viés , Psicometria , Tamanho da Amostra
20.
BMC Res Notes ; 12(1): 240, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036060

RESUMO

OBJECTIVES: Loneliness is individual's subjective sense of lacking familial or social contact to the degree that they wanted. It is responsible for reduced quality of life. The aim of this study was to determine loneliness and its association with year of study among University of Gondar students, 2018/19. Cross-sectional study design was used on 404 Medical and Health Sciences students selected by systematic random sampling. UCLA-R loneliness score was used. A person with a mean value of 42 and above was considered as lonely. After data were collected by self-administered questionnaire, Epi-Data was used for data entry and exported to SPSS version 20.1 for analysis. Variables with p-value of 0.05 and lower were treated as significant factors in multivariable logistic regression. RESULTS: Prevalence of loneliness was 49.5% (95% CI 44.6-54.4%). Year of study was significantly associated with loneliness [AOR = 2.47, 95% CI (1.65-3.70)]. First-year students were having 2.47 odds of loneliness as compared to second year and above students. Loneliness prevalence was higher in the current study. This must get the attention of higher education institutions, the government and all concerned stakeholders in the education sector to design strategy on preventing and treating loneliness.


Assuntos
Solidão/psicologia , Qualidade de Vida/psicologia , Estudantes de Medicina/psicologia , Adolescente , Estudos Transversais , Etiópia , Feminino , Humanos , Modelos Logísticos , Masculino , Tamanho da Amostra , Inquéritos e Questionários , Fatores de Tempo , Universidades , Adulto Jovem
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