Trajectories, predictors, and adolescent health outcomes of childhood weight gain : a growth mixture model

textObesity, as defined as BMI at or above the 95th percentile on the Centers for Disease Control and Prevention’s growth charts, has increased almost 3-fold among children in the United States since 1980. Overweight in adolescence has been associated with increased fat retention and high blood pressure in adulthood, among other symptoms of metabolic syndrome. However, normative patterns of weight change in childhood have not been developed. Groups of children may follow different trajectory patterns of BMI change over time. If common trajectory patterns could be identified, and their risk factors and outcomes understood, more nuanced intervention with families and children at risk for obesity could be developed. This study used a national dataset of 1,364 children whose weight and length was measured 12 times from birth through 15 ½ years. Testing both latent class growth analysis and growth mixture modeling identified four distinct subgroups, or classes, of BMI growth trajectory from 24 months – 8th grade. These classes were compared on numerous demographic, biological, and psychosocial risk factors identified in previous research as related to obesity. Classes were differentiated primarily on the child’s BMI at 15 months, the mother’s BMI at 15 months, birth weight for age, and percent increase in birth weight. Being male, Black, and lower SES were also related to membership in the higher-BMI trajectory classes. Of the psychosocial factors, maternal sensitivity, maternal depression, and attachment classification were also related to BMI class. Membership in these trajectories strongly predicted weight-related and blood-pressure outcomes at 15 ½ years over and above individual risk factors, demonstrating that patterns of change themselves are highly influential. The best-fitting models of weight-related outcomes at 15 ½ years included change trajectory in combination with biological, psychosocial, and SES risk factors from 0-24 months, with R² ranging from .31 = .50. Characteristics predicting adolescent overweight can be identified in the first years of life and should trigger the development and implementation of early intervention protocols in obstetrics and pediatrics.Human Development and Family Science

Toward a developmental origin of the predictors of health : how representations of childhood are associated with well-being in adulthood

textIn this study I explored whether the way adults think about their early childhood is related to their perception of control, coping strategies, and health outcomes. The participants (N=78) in this study were administered the Adult Attachment Interview (AAI) between 1 and 18 years ago, when they were new parents. The current online survey assessed perceived control (a composite of the Perceived Health Competency Scale and a general life control item), coping strategies (generated from a factor analysis of the Brief C.O.P.E. measure), anxiety (GAD-7), overweight (a composite of waist-to-hip ratio by body mass index), lifetime number of mental health diagnoses, and lifetime number of physical health diagnoses. As expected, non-problem-focused coping strategies and low perceived control were significantly associated with overweight and poor mental and physical health outcomes. This study added a developmental component to explain the roots of these maladaptive strategies: Dismissing speech on the AAI, characterized by idealizing childhood, minimizing childhood needs and/or distress, and emphasizing the normalcy and independence of one's upbringing strongly negatively predicted current perceived control and approach coping, relative to Secure speech. In fact, Dismissing speakers endorsed using fewer coping strategies over all. Given the pervasive influence of perceived control and active coping on myriad aging and health outcomes, the origins of these strengths is of particular interest. Dismissing speakers, although they endorse experiencing less anxiety, are clearly faring the worst. Attachment theory as a framework for explaining lifespan agency, anxiety, health behaviors, and outcomes is discussed.Human Development and Family Science

Supports for degenerate stochastic differential equations with jumps and applications

In the paper, we are concerned with degenerate stochastic differential equa- tions with jumps. Firstly, we establish two support theorems for the solutions of the degenerate stochastic equations, under different (sufficient) conditions. Secondly, we ap- ply one of our support theorems to a class of degenerate stochastic evolution equations (i.e., infinite-dimensional stochastic differential equations) with jumps to get a charac- terisation of path-independence for the densities of their Girsanov transformations

Global existence of solutions for the relativistic Boltzmann equation with arbitrarily large initial data on a Bianchi type I space-time

We prove, for the relativistic Boltzmann equation on a Bianchi type I space-time, a global existence and uniqueness theorem, for arbitrarily large initial data.Comment: 17 page

Constructing Sublinear Expectations on Path Space

We provide a general construction of time-consistent sublinear expectations on the space of continuous paths. It yields the existence of the conditional G-expectation of a Borel-measurable (rather than quasi-continuous) random variable, a generalization of the random G-expectation, and an optional sampling theorem that holds without exceptional set. Our results also shed light on the inherent limitations to constructing sublinear expectations through aggregation.Comment: 28 pages; forthcoming in 'Stochastic Processes and their Applications

The Bismut-Elworthy-Li type formulae for stochastic differential equations with jumps

Consider jump-type stochastic differential equations with the drift, diffusion and jump terms. Logarithmic derivatives of densities for the solution process are studied, and the Bismut-Elworthy-Li type formulae can be obtained under the uniformly elliptic condition on the coefficients of the diffusion and jump terms. Our approach is based upon the Kolmogorov backward equation by making full use of the Markovian property of the process.Comment: 29 pages, to appear in Journal of Theoretical Probabilit

Balance, growth and diversity of financial markets

A financial market comprising of a certain number of distinct companies is considered, and the following statement is proved: either a specific agent will surely beat the whole market unconditionally in the long run, or (and this "or" is not exclusive) all the capital of the market will accumulate in one company. Thus, absence of any "free unbounded lunches relative to the total capital" opportunities lead to the most dramatic failure of diversity in the market: one company takes over all other until the end of time. In order to prove this, we introduce the notion of perfectly balanced markets, which is an equilibrium state in which the relative capitalization of each company is a martingale under the physical probability. Then, the weaker notion of balanced markets is discussed where the martingale property of the relative capitalizations holds only approximately, we show how these concepts relate to growth-optimality and efficiency of the market, as well as how we can infer a shadow interest rate that is implied in the economy in the absence of a bank.Comment: 25 page

Design engineers and technical professionals at work: Observing information usage in the workplace

This exploratory study examines how design engineers and technical professionals (hereafter referred to as engineers) in innovative high-tech firms in the United States and India use information in their daily work activities including research, development, and management. The researchers used naturalistic observation to conduct a series of daylong workplace observations with 103 engineers engaged in product design and testing in four U.S.- and two India-based firms. A key finding is that engineers spend about one fourth of their day engaged in some type of information event, which was somewhat lower than the percentage identified in previous research. The explanation may be rooted in the significant change in the information environment and corporate expectations in the last 15 years, which is the time of the original study. Searching technology has improved, making searching less time consuming, and engineers are choosing the Internet as a primary source even though information may not be as focused, as timely, or as authoritative. The study extends our understanding of the engineering workplace, and the information environment in the workplace, and provides information useful for improving methods for accessing and using information, which could ultimately lead to better job performance, facilitate innovation, and encourage economic growth

Global Solution to the Relativistic Enskog Equation With Near-Vacuum Data

We give two hypotheses of the relativistic collision kernal and show the existence and uniqueness of the global mild solution to the relativistic Enskog equation with the initial data near the vacuum for a hard sphere gas.Comment: 6 page