Production and transfer of energy and information in Hamiltonian systems

We present novel results that relate energy and information transfer with sensitivity to initial conditions in chaotic multi-dimensional Hamiltonian systems. We show the relation among Kolmogorov-Sinai entropy, Lyapunov exponents, and upper bounds for the Mutual Information Rate calculated in the Hamiltonian phase space and on bi-dimensional subspaces. Our main result is that the net amount of transfer from kinetic to potential energy per unit of time is a power-law of the upper bound for the Mutual Information Rate between kinetic and potential energies, and also a power-law of the Kolmogorov-Sinai entropy. Therefore, transfer of energy is related with both transfer and production of information. However, the power-law nature of this relation means that a small increment of energy transferred leads to a relatively much larger increase of the information exchanged. Then, we propose an ?experimental? implementation of a 1-dimensional communication channel based on a Hamiltonian system, and calculate the actual rate with which information is exchanged between the first and last particle of the channel. Finally, a relation between our results and important quantities of thermodynamics is presented

Nonlinear model standardization for the analysis and design of nonlinear systems with multiple equilibria

In engineering practice, a nonlinear system stable about several equilibria is often studied by linearizing the system over a small range of operation around each of these equilibria, and allowing the study of the system using linear system methods. Theoretically, for operations beyond a small range but still within the stable regime of an equilibrium, the system behaves nonlinearly, and can be described and investigated using the Volterra series approach. However, there is still no available approach that can systematically transform the model of a nonlinear system into a form that can be studied over the whole stable regime about an equilibrium so as to facilitate the system study using the Volterra series approach. This transformation is, in the present study, referred to as nonlinear model standardization, which is the extension of the well-known concept of linearization to the nonlinear case. In this paper, a novel approach to nonlinear model standardization is proposed for nonlinear systems that can be described by a Nonlinear AutoRegressive model with eXogeneous input (NARX) or a nonlinear differential equation (NDE) model. The proposed approach is then used in three case studies covering the applications in nonlinear system analysis, nonlinear system design, and nonlinearity compensation, respectively, demonstrating the significance of the proposed nonlinear model standardization in a wide range of engineering practices

Determinants of masticatory performance in dentate adults

Masticatory performance results fi om a complex interplay of direct and indirect effects, yet most studies employ univariate models. This study tested a multivariate model of masticatory performance for dentate subjects. Explanatory variables included number of functional tooth units, bite force, sex, age, masseter cross-sectional area, presence of temporomandibular disorders. and presence of diabetes mellitus. The population-based sample consisted of 631 dentate subjects aged 37-80 years. Convariance structure analysis showed that 68%, of the variability in masticatory performance could be explained by the combined effects of the explanatory variables. Age and sex did not show a strong effect on masticatory performance, either directly or indirectly through masseter cross-sectional area, temporomandibular disorders. and bite force. Number of functional tooth units and bite force were confirmed as the key determinants of masticatory performance, which suggests that their maintenance may be of major importance for promoting healthful functional status. (C) 2001 Elsevier Science Ltd. All rights reserved.46764164

Dietary intake in edentulous subjects with good and poor quality complete dentures

Statement of problem. previous studies in complete denture wearers evaluated the relationship betweene diet and measures of chewing, yet only isolated nutrient intake was considered. This limited information makes the assessment of overall diet quality, and the planning of interventions difficult. Purpose. This study investigated the relationship of complete denture quality to masticatory perfor mance, perceived ability to chew, and diet quality as measured by the Healthy Hating Index (HEI), an overall diet quality index. Material and methods. The study population comprised 54 complete denture wearers. Data were obtained from clinical examinations, masticatory performance measurements, and 2 non-consecutive 24-hour dietary recalls, (Masticatory performance data were not collected for 9 subjects because of time constraints, patient fatigue, or patient refusal. Statistical analysis showed no significant effect of their absence on the reported findings.) Based on a composite rating scale, subjects were divided into 3 denture quality groups described as good, medium, and poor. The outcome variables were the HEI and its components, plus selected nutrient and non-nutrient intake. Explanatory variables were quality of complete dentures, masticatory performance, and reported chewing ability. Data were analyzed with Kruskal-Wallis tests, Mann-Whitney U-tests, and Fisher exact tests. Because a large number of dietary components were examined, results were considered significant at alpha = .01. Results. Masticatory performance and perceived ability to chew were unrelated to diet quality. The good quality denture group had significantly better masticatory performance than the medium and poor quality groups, but the median HEI scores and dietary intakes were not significantly different among these 3 groups. Milk, vegetable, fruit, and grain intake scores were mainly responsible for the low overall HEI scores. Conclusion. In the population evaluated, complete denture quality, food comminution capacity, and perceived chewing ability were not related to diet quality. The majority of subjects had deficient diets regardless of the technical quality of their dentures.87549049

Evidence of Sex-specific Differences in Masticatory Jaw Movement Patterns

The complexity of human oral functional movements has not been studied in detail quantitatively, and only recently have studies begun to evaluate whether such movements contain sex-specific characteristics. Therefore, the purposes of this study were: (1) to quantify in detail the jaw movements and associated masticatory electromyographic activity occurring during gum chewing, and (2) to explore these data for evidence of sex specificity. Fourteen male and 17 female subjects participated in the study. Approximately 11 right- and 11 left-sided chewing cycles and associated masticatory electromyographic activity were sampled from each subject. The samples were quantified into 165 variables per chewing cycle, averaged to create a single multivariate vector for each subject, and then analyzed by a step-wise discriminant analysis. With a combination of 6 variables, a jackknifed cross-validation test found the probability of correct classification to be 93.5%. These findings support the hypothesis that masticatory jaw movements contain sex-specific features.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66870/2/10.1177_00220345970760031301.pd