Mutual information rate and bounds for it

The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two data sets (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators

Evaluating the Impact of an Interprofessional Practice Experience Involving Pharmacy and Dental Students on Medication Histories within an Urban Academic Dental Admissions Clinic

Primary Objective: To compare interprofessional (IP) care versus standard care on medication history clarifications in dental patients. Secondary Objectives: To assess the clinical significance of these clarifications with regards to the potential impact on dental treatment plans. To describe the interventions provided by IP care to clarify discrepancies and/or resolve medication-related problems

A cost-effectiveness analysis of a hydration response technology dressing in the treatment of venous leg ulcers in the UK

Introduction: Venous leg ulceration causes significant pain and suffering for patients, additionally it places considerable financial and service burden on the National Health Service (NHS). A large proportion of venous leg ulceration do not heal within the standard time frames of 16 – 24 weeks, resulting in static wounds which commonly have issues with increasing exudate production. Static wounds can have significant negative impact on the patients quality of life, the wound bed and periwound skin, increased risk of infection all of which results in delayed wound healing and increased health service costs. As the NHS continues to face times of austerity, services need to find solutions to be able to reduce cost and release nursing time whilst maintaining standards of care. Cutimed® Sorbion® Sachet S is a treatment option for the management of patients with a venous leg ulceration. The objective of this study was to provide an update of the health economic analysis of Cutimed® Sorbion® Sachet S in comparison to relevant comparators in the UK with current cost data. Methods: Cutimed® Sorbion® Sachet S was compared against Zetuvit Plus, DryMax extra, KerraMax Care and Eclypse from a cost effectiveness perspective. Clinical data were derived from literature and expert opinion. Cost input was utilized based on publicly available data and literature. The average patient in the model is assumed to be 65 years with a diagnosed venous leg ulcer. It is assumed that patients in the different treatment arms have the same background mortality, hence the endpoint mortality is not included in the model. The analysis is based on a deterministic Markov model derived from Harding et al. with weekly cycles. The following assumptions are made: First, all patients start in a static health state with a non-healed but non-progressing venous leg ulcer. It is assumed in the model that patients can transition to a deteriorating health state where a wound is improving or the wound could progress. Additionally, venous leg ulcers could be healed from a progressed wound (i.e. improved wound), they could develop into a severe wound with complications (infections) to be treated in hospitals. The time frame for the analysis was fixed for one year and no re-occurence after healing was assumed to happen. Results: The cost-effectiveness analysis demonstrates health economic dominance of Cutimed® Sorbion® Sachet S being more effective and cost-saving against all analysed comparators. When using literature-based input values the incrementally higher healing rates for Cutimed® Sorbion® Sachet S are 11.04 months (versus Zetuvit Plus), 29.04 months (versus DryMax extra), 1.68 months (versus KerraMax Care) and 11.04 months (versus Eclypse). Cost savings per patient were 37.60£ (versus Zetuvit Plus), 171.68£ (versus DryMax extra), 3.13£ (versus KerraMax Care) and 43.63£ (versus Eclypse). Clinical benefits and cost savings are increasing when real life practice assumptions based on expert opinion are included. Conclusions: Based on the underlying health economic model, Cutimed® Sorbion® Sachet S is more effective and less costly than other comparative products in venous leg ulcers in the UK

Designing and Evaluating an Interprofessional Practice Experience Involving Dental and Pharmacy Students

Purpose: To describe the design and evaluation of an innovative interprofessional practice experience involving pharmacy and dental students. Background: Accreditation standards for pharmacy and dentistry schools mandate that interprofessional education (IPE) is introduced and practiced throughout the curriculum. There is a paucity of data involving interprofessional practice experiences with dental and pharmacy students. Description of Program: Pharmacy and dental student-teams conduct health and medication histories for patients seen at Temple University’s dental admissions clinic. Additionally, these teams collaborate to conduct tobacco cessation counseling for current tobacco users. This interprofessional practice experience was designed to prepare students to build more effective collaborative healthcare teams. In order to evaluate this experience, we measured student perceptions with the SPICE-R Instrument and collected student and faculty feedback regarding achievement of pre-specified learning objectives for the experience. Preliminary Results: The SPICE-R pre- and post-surveys were completed by 108 students (80 dental and 18 pharmacy) as part of the experience. Mean item scores significantly increased, indicating that student perceptions were more favorable after the practice experience. Mean scores on factor subscales significantly increased for all students (Interprofessional Teamwork and Team-Based Practice from 4.35 to 4.63, p\u3c0.001; Roles/Responsibilities for Collaborative Practice from 4.08 to 4.48, p\u3c0.001; Patient Outcomes from Collaborative Practice from 4.3 to 4.57, p\u3c0.001). The item and factor subscale increases were similar when analyzed separately by profession. The majority of dental and pharmacy faculty and students agreed that the learning objectives of this practice experience were achieved. Relevance: Pharmacy and dental students’ perceptions about IPE and collaborative practice were more favorable after completing this interprofessional practice experience which is consistent with previous studies. Recommendations: Evaluation of student perceptions of IPE can be utilized as one strategy to demonstrate learner outcomes within IPE. Faculty feedback can be utilized to evaluate IPE outcomes and improve practice experiences. Learning Objectives Describe approaches for engaging students and faculty in interprofessional practice experiences. Describe assessment strategies and tools that can be used to evaluate interprofessional practice experiences. Design an innovative interprofessional curriculum within a collaborative practice environment with attention to actualizing academic and clinical partnerships

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

Optimality of mutation and selection in germinal centers

The population dynamics theory of B cells in a typical germinal center could play an important role in revealing how affinity maturation is achieved. However, the existing models encountered some conflicts with experiments. To resolve these conflicts, we present a coarse-grained model to calculate the B cell population development in affinity maturation, which allows a comprehensive analysis of its parameter space to look for optimal values of mutation rate, selection strength, and initial antibody-antigen binding level that maximize the affinity improvement. With these optimized parameters, the model is compatible with the experimental observations such as the ~100-fold affinity improvements, the number of mutations, the hypermutation rate, and the "all or none" phenomenon. Moreover, we study the reasons behind the optimal parameters. The optimal mutation rate, in agreement with the hypermutation rate in vivo, results from a tradeoff between accumulating enough beneficial mutations and avoiding too many deleterious or lethal mutations. The optimal selection strength evolves as a balance between the need for affinity improvement and the requirement to pass the population bottleneck. These findings point to the conclusion that germinal centers have been optimized by evolution to generate strong affinity antibodies effectively and rapidly. In addition, we study the enhancement of affinity improvement due to B cell migration between germinal centers. These results could enhance our understandings to the functions of germinal centers.Comment: 5 figures in main text, and 4 figures in Supplementary Informatio

Effect of Biodiversity Changes in Disease Risk: Exploring Disease Emergence in a Plant-Virus System

The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species

Interocular yoking in human saccades examined by mutual information analysis

International audienceABSTRACT : BACKGROUND : Saccadic eye movements align the two eyes precisely to foveate a target. Trial-by-trial variance of eye movement is always observed within an identical experimental condition. This has often been treated as experimental error without addressing its significance. The present study examined statistical linkages between the two eyes' movements, namely interocular yoking, for the variance of eye position and velocity. METHODS : Horizontal saccadic movements were recorded from twelve right-eye-dominant subjects while they decided on saccade direction in Go-Only sessions and on both saccade execution and direction in Go/NoGo sessions. We used infrared corneal reflection to record simultaneously and independently the movement of each eye. Quantitative measures of yoking were provided by mutual information analysis of eye position or velocity, which is sensitive to both linear and non-linear relationships between the eyes' movements. Our mutual information analysis relied on the variance of the eyes movements in each experimental condition. The range of movements for each eye varies for different conditions so yoking was further studied by comparing GO-Only vs. Go/NoGo sessions, leftward vs. rightward saccades. RESULTS : Mutual information analysis showed that velocity yoking preceded positional yoking. Cognitive load increased trial variances of velocity with no increase in velocity yoking, suggesting that cognitive load may alter neural processes in areas to which oculomotor control is not tightly linked. The comparison between experimental conditions showed that interocular linkage in velocity variance of the right eye lagged that of the left eye during saccades. CONCLUSIONS : We conclude quantitative measure of interocular yoking based on trial-to-trial variance within a condition, as well as variance between conditions, provides a powerful tool for studying the binocular movement mechanism