Search results for "EQUATION"
showing 10 items of 4219 documents
Are the Motives for Food Choices Different in Orthorexia Nervosa and Healthy Orthorexia?
2019
Recent research points to the bidimensional nature of orthorexia, with one dimension related to interest in healthy eating (healthy orthorexia) and another dimension related to a pathological preoccupation with eating healthily (orthorexia nervosa). Research was needed to provide further support for this differentiation. We examined the food-choice motives related to both aspects of orthorexia. Participants were 460 students from a Spanish university who completed the Teruel Orthorexia Scale and the Food Choice Questionnaire. By means of structural equation modeling, we analyzed the relationship between orthorexia, food-choice motives, gender, body mass index, and age. The motives predictin…
Predicting limiting 'free sugar' consumption using an integrated model of health behavior.
2019
Excess intake of 'free sugars' is a key predictor of chronic disease, obesity, and dental ill health. Given the importance of determining modifiable predictors of free sugar-related dietary behaviors, we applied the integrated behavior change model to predict free sugar limiting behaviors. The model includes constructs representing 'reasoned' or deliberative processes that lead to action (e.g., social cognition constructs, intentions), and constructs representing 'non-conscious' or implicit processes (e.g., implicit attitudes, behavioral automaticity) as predictors of behavior. Undergraduate students (N = 205) completed measures of autonomous and controlled motivation, the theory of planned…
Increasing Neural Stem Cell Division Asymmetry and Quiescence Are Predicted to Contribute to the Age-Related Decline in Neurogenesis.
2018
Summary: Adult murine neural stem cells (NSCs) generate neurons in drastically declining numbers with age. How cellular dynamics sustain neurogenesis and how alterations with age may result in this decline are unresolved issues. We therefore clonally traced NSC lineages using confetti reporters in young and middle-aged adult mice. To understand the underlying mechanisms, we derived mathematical models that explain observed clonal cell type abundances. The best models consistently show self-renewal of transit-amplifying progenitors and rapid neuroblast cell cycle exit. In middle-aged mice, we identified an increased probability of asymmetric stem cell divisions at the expense of symmetric di…
Remarks on GRN-type systems
2020
Systems of ordinary differential equations that appear in gene regulatory networks theory are considered. We are focused on asymptotical behavior of solutions. There are stable critical points as well as attractive periodic solutions in two-dimensional and three-dimensional systems. Instead of considering multiple parameters (10 in a two-dimensional system) we focus on typical behaviors of nullclines. Conclusions about possible attractors are made.
Psychometric properties of the Satisfaction with Job Life Scale in Portuguese workers: A systematic study based on the IRT and CFA modeling
2020
Job satisfaction is related to better physical and mental health, as well as to factors specifically related to work. In this context, the measurement of work satisfaction is important for organizations that profess an interest in engaged and satisfied workers. Therefore, this study aims to examine the psychometric properties of the Satisfaction with Job Life Scale (SWJLS) in Portuguese workers by combining the procedures of the Classical Test Theory (CTT) and the Item Response Theory (IRT). Specifically, internal structure of the scale was studied, its reliability (consistency), correlations with other measures of wellbeing (life satisfaction, loneliness, emotional wellbeing at work, and j…
Discovering Differential Equations from Earth Observation Data
2020
Modeling and understanding the Earth system is a constant and challenging scientific endeavour. When a clear mechanistic model is unavailable, complex or uncertain, learning from data can be an alternative. While machine learning has provided excellent methods for detection and retrieval, understanding the governing equations of the system from observational data seems an elusive problem. In this paper we introduce sparse regression to uncover a set of governing equations in the form of a system of ordinary differential equations (ODEs). The presented method is used to explicitly describe variable relations by identifying the most expressive and simplest ODEs explaining data to model releva…
Dynamical Features of the MAP Kinase Cascade
2017
The MAP kinase cascade is an important signal transduction system in molecular biology for which a lot of mathematical modelling has been done. This paper surveys what has been proved mathematically about the qualitative properties of solutions of the ordinary differential equations arising as models for this biological system. It focuses, in particular, on the issues of multistability and the existence of sustained oscillations. It also gives a concise introduction to the mathematical techniques used in this context, bifurcation theory and geometric singular perturbation theory, as they relate to these specific examples. In addition further directions are presented in which the application…
Effectiveness of the physical activity intervention program in the PREDIMED-Plus study: a randomized controlled trial
2018
[Background] The development and implementation of effective physical activity (PA) intervention programs is challenging, particularly in older adults. After the first year of the intervention program used in the ongoing PREvención con DIeta MEDiterránea (PREDIMED)-Plus trial, we assessed the initial effectiveness of the PA component.
Adolescent sugar-sweetened beverage consumption: An extended Health Action Process Approach.
2019
Abstract Objective Consumption of excess added sugar in the form of sugar-sweetened beverages (SSBs) contributes to a wide range of health concerns in adolescents. Identification of modifiable determinants of SSB consumption based on behavioral theory may inform development of interventions aimed at reducing SSB consumption. The aim of the current study was to test the efficacy of an extended version of the Health Action Process Approach to predict adolescent SSB consumption. Methods Using a prospective design, adolescent students (N = 450) self-reported their outcome expectancies, perceived behavioral control, intentions, habit, action, maintenance, and recovery self-efficacy, action and c…
Yogurt consumption and abdominal obesity reversion in the PREDIMED study.
2016
Yogurt consumption and abdominal obesity reversion in the PREDIMED study. BACKGROUND AND AIMS: Evidence on the association yogurt consumption and obesity is not conclusive. The aim of this study was to prospectively evaluate the association between yogurt consumption, reversion of abdominal obesity status and waist circumference change in elderly. METHODS AND RESULTS: 4545 individuals at high cardiovascular risk were prospectively followed. Total, whole-fat and low-fat yogurt consumption were assessed using food frequency questionnaires. Generalized estimating equations were used to analyze the association between yogurt consumption and waist circumference change (measured at baseline and y…