The survival function NPMLE for combined right-censored and length-biased right-censored failure time data: properties and applications.

Many cohort studies in survival analysis have imbedded in them subcohorts consisting of incident cases and prevalent cases. Instead of analysing the data from the incident and prevalent cohorts alone, there are surely advantages to combining the data from these two subcohorts. In this paper, we discuss a survival function nonparametric maximum likelihood estimator (NPMLE) using both length-biased right-censored prevalent cohort data and right-censored incident cohort data.

First Nations and Inuit mental health and the Non-Insured Health Benefits program: Urgent priorities for evaluation.

The mental health needs and disparities facing First Nations and Inuit in Canada far exceed those of the general population and yet accessing culturally safe care remains a serious challenge. One means for accessing mental health care is through the Non-Insured Health Benefits (NIHB) mental health counselling program run by Indigenous Services Canada. However, evaluations of the efficacy of the NIHB's mental health counselling program remain entirely absent in the academic literature and this is startling given that this program receives significant federal funding to care for a population that experiences extreme marginalization.

Survival Modelling For Data From Combined Cohorts: Opening the Door to Meta Survival Analyses and Survival Analysis using Electronic Health Records.

Non-parametric estimation of the survival function using observed failure time data depends on the underlying data generating mechanism, including the ways in which the data may be censored and/or truncated. For data arising from a single source or collected from a single cohort, a wide range of estimators have been proposed and compared in the literature. Often, however, it may be possible, and indeed advantageous, to combine and then analyze survival data that have been collected under different study designs.

A nonparametric test for equality of survival medians using right-censored prevalent cohort survival data.

The median is a robust summary commonly used for comparison between populations. The existing literature falls short in testing for equality of survival medians when the collected data do not form representative samples from their respective target populations and are subject to right censoring. Such data commonly occur in prevalent cohort studies with follow-up.

Stacked survival models for residual lifetime data.

When modelling the survival distribution of a disease for which the symptomatic progression of the associated condition is insidious, it is not always clear how to measure the failure/censoring times from some true date of disease onset. In a prevalent cohort study with follow-up, one approach for removing any potential influence from the uncertainty in the measurement of the true onset dates is through the utilization of only the residual lifetimes. As the residual lifetimes are measured from a well-defined screening date (prevalence day) to failure/censoring, these observed time durations are essentially error free.

Correction: The Good Food for Learning Universal Curriculum-Integrated Healthy School Lunch Intervention: Protocol for a Two-Year Matched Control Pre-Post and Case Study.

[This corrects the article DOI: 10.2196/30899.].

The Good Food for Learning Universal Curriculum-Integrated Healthy School Lunch Intervention: Protocol for a Two-Year Matched Control Pre-Post and Case Study.

Background: Good nutrition affects children's health, well-being, and learning, and schools offer an important setting to promote healthy behaviors that can last a lifetime. Once children reach school age, they spend more of their waking hours in school than in any other environment. Children's eating habits may be easier to influence than those of adults.

A risk set adjustment for proportional hazards modeling of combined cohort data.

Sporting careers observed over a preset time interval can be partitioned into two distinct subsamples. These samples consist of individuals whose careers had already commenced at the start of the time interval (prevalent subsample) and individuals whose careers began during the time interval (incident subsample) as well the respective individual-level covariate data such as salary, height, weight, performance statistics, draft position, etc. Under the assumption of a proportional hazards model, we propose a partial likelihood estimator to model the effect of covariates on survival via an adjusted risk set sampling procedure for when the incident cohort data is used in conjunction with the prevalent cohort data.

Parametric models for combined failure time data from an incident cohort study and a prevalent cohort study with follow-up.

A classical problem in survival analysis is to estimate the failure time distribution from right-censored observations obtained from an incident cohort study. Frequently, however, failure time data comprise two independent samples, one from an incident cohort study and the other from a prevalent cohort study with follow-up, which is known to produce length-biased observed failure times. There are drawbacks to each of these two types of study when viewed separately.

Is testosterone linked to human aggression? A meta-analytic examination of the relationship between baseline, dynamic, and manipulated testosterone on human aggression.

Testosterone is often considered a critical regulator of aggressive behaviour. There is castration/replacement evidence that testosterone indeed drives aggression in some species, but causal evidence in humans is generally lacking and/or-for the few studies that have pharmacologically manipulated testosterone concentrations-inconsistent. More often researchers have examined differences in baseline testosterone concentrations between groups known to differ in aggressiveness (e.

Parametric modelling of prevalent cohort data with uncertainty in the measurement of the initial onset date.

In prevalent cohort studies with follow-up, if disease duration is the focus, the date of onset must be obtained retrospectively. For some diseases, such as Alzheimer's disease, the very notion of a date of onset is unclear, and it can be assumed that the reported date of onset acts only as a proxy for the unknown true date of onset. When adjusting for onset dates reported with error, the features of left-truncation and potential right-censoring of the failure times must be modeled appropriately.

Exploring Women's Preferences for the Mode of Delivery in Twin Gestations: Results of the Twin Birth Study.

Objective: The Twin Birth Study, an international, multi-center randomized controlled trial was conducted to compare the risks of planned cesarean with planned vaginal delivery for twin pregnancies. The aim of this component of the trial was to understand participants' perspectives of study participation and preferences for the mode of delivery.

Methods: A mixed-methods questionnaire was distributed to study participants 3 months after giving birth.

It's the talk: a study of involvement initiatives in secure mental health settings.

Background: A study of involvement initiatives within secure mental health services across one UK region, where these have been organized to reflect alliances between staff and service users. There is little previous relevant international research, but constraints upon effective involvement have been noted.

Objective: To explore and evaluate involvement initiatives in secure mental health settings.

Synthesis of TiO(2) nanoframe and the prototype of a nanoframe solar cell.

Nanoframes containing 20 nm diameter TiO(2) nanowire arrays were synthesized with polymer templates via cathodic sol-gel deposition followed by 450 degrees C sintering. Raman spectra indicated that they are composed of pure anatase TiO(2). The nanowire array inside the nanoframe was confirmed to be single crystalline by high resolution TEM.

Ultra-high-yield growth of vertical single-walled carbon nanotubes: Hidden roles of hydrogen and oxygen.

An oxygen-assisted hydrocarbon chemical vapor deposition method is developed to afford large-scale, highly reproducible, ultra-high-yield growth of vertical single-walled carbon nanotubes (V-SWNTs). It is revealed that reactive hydrogen species, inevitable in hydrocarbon-based growth, are damaging to the formation of sp(2)-like SWNTs in a diameter-dependent manner. The addition of oxygen scavenges H species and provides a powerful control over the C/H ratio to favor SWNT growth.

Suxamethonium-induced muscle pains are not related to cholinesterase activity.

We have investigated the possibility of using the pre-operative measurement of cholinesterase activity to predict the postoperative development of myalgia following the administration of suxamethonium. Seventy-seven patients presenting for elective extraction of wisdom teeth were entered in the study. All patients received a standard anaesthetic regimen, including suxamethonium to facilitate tracheal intubation, and standardised postoperative analgesia.

Subnanogram quantitation of chlorpheniramine in plasma by a new radioimmunoassay and comparison with a liquid chromatographic method.

A new radioimmunoassay (RIA) procedure for the quantitation of chlorpheniramine in plasma is described. The assay allows the determination of chlorpheniramine levels up to 96 h after oral administration of a single 4-mg tablet to healthy volunteers. This procedure was sensitive to a 156-pg/mL plasma concentration when a 100-microL plasma sample was used.