Maximum likelihood estimate

In the last decade, the Fossilized Birth-Death (FBD) process has yielded interesting clues about the evolution of biodiversity through time. To facilitate such studies, we extend our method to compute the probability density of phylogenetic trees of extant and extinct taxa in which the only temporal information is provided by the fossil ages (i.e. without the divergence times) in order to deal with the piecewise constant FBD process, known as the "skyline FBD", which allows rates to change between pre-defined time intervals, as well as modelling extinction events at the bounds of these intervals...

OBJECTIVE: To verify the accuracy of the maximum phonation time of the vowel /a/ (MPT/a/), fricative /s/ (MPT/s/), number counting (MPTC), and number reached in this count (CN) to estimate forced vital capacity (FVC) in patients with post-COVID-19 syndrome. METHOD: Cross-sectional study involving adult patients, who were admitted to the intensive care unit and referred to the Post-COVID-19 Rehabilitation Outpatient Clinic. Voice function was assessed using a Vocal Handicap Index (VHI) self-assessment questionnaire and MPT tests...

Despite the well-established link between physical activity and positive health outcomes, much of the world's population remains inactive. Many people don't invest in health behaviours, such as physical activity, in the present, despite the long-term benefits of this. The aim of this study was to assess the relationship between physical activity levels and risk and time preferences in university students. A maximum likelihood model was used to jointly estimate risk and time preferences (elicited in an incentivised choice experiment), and to examine the relationship between these preferences and self-reported physical activity...

Genome-wide association studies (GWAS) have identified many genetic loci associated with complex traits and diseases in the past 20 years. Multiple heritable covariates may be added into GWAS regression models to estimate direct effects of genetic variants on a focal trait, or to improve the power by accounting for environmental effects and other sources of trait variations. When one or more covariates are causally affected by both genetic variants and hidden confounders, adjusting for them in GWAS will produce biased estimation of SNP effects, known as collider bias...

The complex interactions were performed among non-pharmaceutical interventions, vaccinations, and hosts for all epidemics in mainland China during the spread of COVID-19. Specially, the small-scale epidemic in the city described by SVEIR model was less found in the current studies. The SVEIR model with control was established to analyze the dynamical and epidemiological features of two epidemics in Jinzhou City led by Omicron variants before and after Twenty Measures. In this study, the total population ( N ) of Jinzhou City was divided into five compartments: the susceptible ( S ), the vaccinated ( V ), the exposed ( E ), the infected ( I ), and the recovered ( R )...

Epidemiologic screening programs often make use of tests with small, but non-zero probabilities of misdiagnosis. In this article, we assume the target population is finite with a fixed number of true cases, and that we apply an imperfect test with known sensitivity and specificity to a sample of individuals from the population. In this setting, we propose an enhanced inferential approach for use in conjunction with sampling-based bias-corrected prevalence estimation. While ignoring the finite nature of the population can yield markedly conservative estimates, direct application of a standard finite population correction (FPC) conversely leads to underestimation of variance...

BACKGROUND: Previous studies have reported conflicting factor structures of the Coping Strategies Questionnaire - Sickle Cell Disease (CSQ-SCD). This study examined the psychometric properties of the CSQ-SCD among adults with SCD in the United States. METHODS: This study implemented a cross-sectional study design with web-based self-administered surveys. Individuals with SCD were recruited via an online panel. Psychometric properties, including factorial and construct validity, and internal consistency reliability, of the CSQ-SCD were assessed...

BACKGROUND: Instrumental variable (IV) methods are widely employed to estimate causal effects when concerns regarding unmeasured confounders. Although comparisons among several IV methods for binary outcomes exist, comprehensive evaluations are insufficient. Therefore, in this study, we aimed to conduct a simulation with some settings for a detailed comparison of these methods, focusing on scenarios where IVs are valid and under effect homogeneity with different instrument strengths. METHODS: We compared six IV methods under 32 simulation scenarios: two-stage least squares (2SLS), two-stage predictor substitutions (2SPS), two-stage residual inclusions (2SRI), limited information maximum likelihood (LIML), inverse-variance weighted methods with a linear outcome model (IVWLI ), and inverse-variance weighted methods with a non-linear model (IVWLL )...

Rhipicephalus (Boophilus) microplus causes considerable livestock production losses. Knowledge of the traits that influence tick resistance contributes to the development of breeding strategies designed to improve herd productivity. Within this context, this study evaluated the resistance of Caracu, a tropically adapted cattle breed, to R. microplus. Tick count, hair length, coat thickness, and coat color were evaluated in 202 naturally tick-infested females (cows and heifers) over a period of 18 months...

This study hypothesizes that depression mediates the association between exposure to stigma and medication non-adherence in people living with HIV (PLHIV). We recruited 372 PLHIV from the Stigma, health-related Quality of life, antiretroviral Adherence, and Depression among people living with HIV (SQuAD-HIV) project, a multicenter cross-sectional study conducted between October 2021 and February 2022 among PLHIV attending six ART clinics in two geopolitical regions of northern Nigeria. A structural equation modeling (SEM) framework, utilizing the full information maximum likelihood estimator, was used to elucidate the pathways linking stigma, depression, and ART medication adherence, adjusting for sociodemographic characteristics...

In this study, as part of basic research aimed at enhancing the accuracy of load and resistance coefficients to ensure their suitability for practical design and promoting the application of underutilized reliability-based design in Korea, the author conducts optimal design based on the reliability analysis of a vertical-type breakwater in the seas off of Haeundae, Yeosu, Mokpo, Gunsan, and Incheon-representative ports in Korea. In doing so, the author utilized the double-loop approach, which simultaneously addresses a reliability problem nested within an optimization process, employing the Polak-He optimization algorithm...

Introduction: DNA methylation, specifically the formation of 5-methylcytosine at the C5 position of cytosine, undergoes reproducible changes as organisms age, establishing it as a significant biomarker in aging studies. Epigenetic clocks, which integrate methylation patterns to predict age, often employ linear models based on penalized regression, yet they encounter challenges in handling missing data, count-based bisulfite sequence data, and interpretation. Methods: To address these limitations, we introduce BayesAge, an extension of the scAge methodology originally designed for single-cell DNA methylation analysis...

This paper aims to introduce a novel family of probability distributions by the well-known method of the T-X family of distributions. The proposed family is called a "Novel Generalized Exponent Power X Family" of distributions. A three-parameters special sub-model of the proposed method is derived and named a "Novel Generalized Exponent Power Weibull" distribution (NGEP-Wei for short). For the proposed family, some statistical properties are derived including the hazard rate function, moments, moment generating function, order statistics, residual life, and reverse residual life...

In screening large populations a diagnostic test is frequently used repeatedly. An example is screening for bowel cancer using the fecal occult blood test (FOBT) on several occasions such as at 3 or 6 days. The question that is addressed here is how often should we repeat a diagnostic test when screening for a specific medical condition. Sensitivity is often used as a performance measure of a diagnostic test and is considered here for the individual application of the diagnostic test as well as for the overall screening procedure...

Inferring past demographic history of natural populations from genomic data is of central concern in many studies across research fields. Previously, our group had developed dadi, a widely used demographic history inference method based on the allele frequency spectrum (AFS) and maximum composite likelihood optimization. However, dadi's optimization procedure can be computationally expensive. Here, we present donni (demography optimization via neural network inference), a new inference method based on dadi that is more efficient while maintaining comparable inference accuracy...

BACKGROUND: Causal association between chronic obstructive pulmonary disease (COPD) and heart failure (HF) has been controversial. This study used Mendelian Randomization (MR) analysis to clarify the potential causal connection between these two conditions. OBJECTIVES: The purpose of the study was to investigate the causal relationship between COPD and HF based on the hypothesis that the genetic predisposition to COPD could lead to an increased risk of developing HF METHODS: A two-sample MR analysis of genetic data was performed for COPD and HF...

In this paper, we consider the structural change in a class of discrete valued time series, where the true conditional distribution of the observations is assumed to be unknown. The conditional mean of the process depends on a parameter <mml:math xmlns:mml="https://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>θ</mml:mi><mml:mo>∗</mml:mo></mml:msup></mml:math> which may change over time. We provide sufficient conditions for the consistency and the asymptotic normality of the Poisson quasi-maximum likelihood estimator (QMLE) of the model...

BACKGROUND: There is a high prevalence of mental illness in nursing home residents compared to older adults living in the community. This was highlighted in the most recent comprehensive systematic review on the topic, published in 2010. In the context of a rapidly aging population and increased numbers of older adults requiring residential care, this study aims to provide a contemporary account of the prevalence of mental illness among nursing home residents. METHODS: This protocol was prepared in line with the PRISMA-P 2015 Statement...

In studies with time-to-event outcomes, multiple, inter-correlated, and time-varying covariates are commonly observed. It is of great interest to model their joint effects by allowing a flexible functional form and to delineate their relative contributions to survival risk. A class of semiparametric transformation (ST) models offers flexible specifications of the intensity function and can be a general framework to accommodate nonlinear covariate effects. In this paper, we propose a partial-linear single-index (PLSI) transformation model that reduces the dimensionality of multiple covariates into a single index and provides interpretable estimates of the covariate effects...

Single-index models are becoming increasingly popular in many scientific applications as they offer the advantages of flexibility in regression modeling as well as interpretable covariate effects. In the context of survival analysis, the single-index hazards models are natural extensions of the Cox proportional hazards models. In this paper, we propose a novel estimation procedure for single-index hazard models under a monotone constraint of the index. We apply the profile likelihood method to obtain the semiparametric maximum likelihood estimator, where the novelty of the estimation procedure lies in estimating the unknown monotone link function by embedding the problem in isotonic regression with exponentially distributed random variables...