scholarly journals Inferring temporal dynamics from cross-sectional data using Langevin dynamics

2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Pritha Dutta ◽  
Rick Quax ◽  
Loes Crielaard ◽  
Luca Badiali ◽  
Peter M. A. Sloot
Keyword(s):  
Computational Models ◽  
Predictive Power ◽  
Temporal Dynamics ◽  
Expert Knowledge ◽  
Local Equilibrium ◽  
Langevin Dynamics ◽  
Population Based ◽  
Temporal Information ◽  
Cross Sectional ◽  
Data Points

Cross-sectional studies are widely prevalent since they are more feasible to conduct compared with longitudinal studies. However, cross-sectional data lack the temporal information required to study the evolution of the underlying dynamics. This temporal information is essential to develop predictive computational models, which is the first step towards causal modelling. We propose a method for inferring computational models from cross-sectional data using Langevin dynamics. This method can be applied to any system where the data-points are influenced by equal forces and are in (local) equilibrium. The inferred model will be valid for the time span during which this set of forces remains unchanged. The result is a set of stochastic differential equations that capture the temporal dynamics, by assuming that groups of data-points are subject to the same free energy landscape and amount of noise. This is a ‘baseline’ method that initiates the development of computational models and can be iteratively enhanced through the inclusion of domain expert knowledge as demonstrated in our results. Our method shows significant predictive power when compared against two population-based longitudinal datasets. The proposed method can facilitate the use of cross-sectional datasets to obtain an initial estimate of the underlying dynamics of the respective systems.

Minerals Intake Distributions in a Large Sample of Iranian at-Risk Population Using the National Cancer Institute Method: Do They Meet Their Requirements?

2015 ◽  
Vol 85 (3-4) ◽  
pp. 129-144 ◽  
Author(s):  
Zahra Heidari ◽  
Awat Feizi ◽  
Leila Azadbakht ◽  
Nizal Sarrafzadegan
Keyword(s):  
At Risk ◽  
National Cancer Institute ◽  
Population Based ◽  
Cross Sectional Study ◽  
Normal Function ◽  
Dietary Intakes ◽  
Middle Aged ◽  
Cross Sectional ◽  
Nutritional Interventions ◽  
High Prevalence

Abstract. Background: Minerals are required for the body’s normal function. Aim: The current study assessed the intake distribution of minerals and estimated the prevalence of inadequacy and excess among a representative sample of healthy middle aged and elderly Iranian people. Methods: In this cross-sectional study, the second follow up to the Isfahan Cohort Study (ICS), 1922 generally healthy people aged 40 and older were investigated. Dietary intakes were collected using 24 hour recalls and two or more consecutive food records. Distribution of minerals intake was estimated using traditional (averaging dietary intake days) and National Cancer Institute (NCI) methods, and the results obtained from the two methods, were compared. The prevalence of minerals intake inadequacy or excess was estimated using the estimated average requirement (EAR) cut-point method, the probability approach and the tolerable upper intake levels (UL). Results: There were remarkable differences between values obtained using traditional and NCI methods, particularly in the lower and upper percentiles of the estimated intake distributions. A high prevalence of inadequacy of magnesium (50 - 100 %), calcium (21 - 93 %) and zinc (30 - 55 % for males > 50 years) was observed. Significant gender differences were found regarding inadequate intakes of calcium (21 - 76 % for males vs. 45 - 93 % for females), magnesium (92 % vs. 100 %), iron (0 vs. 15 % for age group 40 - 50 years) and zinc (29 - 55 % vs. 0 %) (all; p < 0.05). Conclusion: Severely imbalanced intakes of magnesium, calcium and zinc were observed among the middle-aged and elderly Iranian population. Nutritional interventions and population-based education to improve healthy diets among the studied population at risk are needed.

The German Version of the Satisfaction With Life Scale (SWLS)

2011 ◽  
Vol 27 (2) ◽  
pp. 127-132 ◽  
Author(s):  
Heide Glaesmer ◽  
Gesine Grande ◽  
Elmar Braehler ◽  
Marcus Roth
Keyword(s):  
Convergent Validity ◽  
Satisfaction With Life ◽  
Age Groups ◽  
Population Based ◽  
Factorial Invariance ◽  
Satisfaction With Life Scale ◽  
Small Samples ◽  
Cross Sectional ◽  
Confirmatory Factor Analyses ◽  
Life Scale

The Satisfaction with Life Scale (SWLS) is the most commonly used measure for life satisfaction. Although there are numerous studies confirming factorial validity, most studies on dimensionality are based on small samples. A controversial debate continues on the factorial invariance across different subgroups. The present study aimed to test psychometric properties, factorial structure, factorial invariance across age and gender, and to deliver population-based norms for the German general population from a large cross-sectional sample of 2519 subjects. Confirmatory factor analyses supported that the scale is one-factorial, even though indications of inhomogeneity of the scale have been detected. Both findings show invariance across the seven age groups and both genders. As indicators of the convergent validity, a positive correlation with social support and negative correlation with depressiveness was shown. Population-based norms are provided to support the application in the context of individual diagnostics.

Association between reproductive factors and postmenopausal osteoporosis

2011 ◽  
Vol 20 (03) ◽  
pp. 248-251
Author(s):  
H. R. Meybodi ◽  
N. Khalili ◽  
P. Khashayar ◽  
R. Heshmat ◽  
A. Hossein-nezhad ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Reproductive Factors ◽  
Population Based ◽  
Age At Menarche ◽  
Mineral Density ◽  
Cross Sectional ◽  
Number Of Children ◽  
Menstrual History ◽  
Duration Of Breastfeeding

SummaryThe present cross-sectional research was designed to study possible correlations between clinical reproductive factors and bone mineral density (BMD) values.Using the data gathered by the population-based Iranian Multicenter Osteoporosis Study (IMOS), we investigated the correlation found between reproductive factors and osteoporosis. Subjects were recruited from five major cities of Iran. Bone mineral density was measured using Dual-Energy X-ray Absorptiometry and the results were analyzed against the age at menarche and at menopause, number of pregnancies, children and abortions, and the history (and duration) of breastfeeding.Data was available for 2528 women. Gravidity and number of children were reversely correlated with BMD. Younger age at menarche was associated with higher BMD values, whereas there was no significant correlation between age at menopause and menstrual history and BMD.Our study suggests that clinical reproductive factors, particularly number of children and breastfeeding, could be incorporated as predictors of BMD levels in women. Given the controversial results obtained in different studies, longitudinal studies should be carried out to enlighten the importance of these factors and the rationale of their use to predict BMD values in different settings.

Sign in / Sign up

Export Citation Format

Share Document