Влияние толщины диффузионного слоя на возникновение динамических неустойчивостей в модельном электрокаталитическом процессе

Определено влияние толщины диффузионного слоя Нернста на возникновение неустойчивостей Хопфа, седло–узел и гомоклинной неустойчивости в модельном электрокаталитическом процессе на поверхности сферического электрода при потенциостатических условиях. Показано, что увеличение толщины диффузионного слоя Нернста способстует расширению области потенциалов (в системе могут наблюдаться спонтанные периодические колебания тока), а также области бистабильности системы. Возможная реализация в системе гомоклинной бифуркации может привести и к более сложным динамическим режимам.Визначено вплив товщини дифузійного шару Нернста на виникнення нестійкості Хопфа, сідло–вузол та гомоклінної нестійкості в модельному електрокаталітичному процесі на поверхні сферичного електроду за потенціостатичних умов. Показано, що збільшення товщини дифузійного шару Нернста спричинює розширення області потенціалів (у системі можуть спостерігатися спонтанні періодичні коливання струму), а також області бістабільності системи. Можлива реалізація в системі гомоклінної біфуркації може привести і до більш складних динамічних режимів.The influence of the Nernst diffusion layer thickness on the appearance of the Hopf instability, saddle–node instability, and homoclinic instability in a model electrocatalytic process on a spherical electrode surface under potentiostatic conditions is determined. It is shown that the Nernst diffusion layer thickness increase leads to an increase in the potential range, where spontaneous periodic current oscillations can be observed and also in the system bistability range. A possible realization of the homoclinic bifurcation in the system can initiate more complicated dynamical regimes

The SOS-framework (Systems of Sedentary behaviours): An international transdisciplinary consensus framework for the study of determinants, research priorities and policy on sedentary behaviour across the life course: A DEDIPAC-study

© 2016 The Author(s).Background: Ecological models are currently the most used approaches to classify and conceptualise determinants of sedentary behaviour, but these approaches are limited in their ability to capture the complexity of and interplay between determinants. The aim of the project described here was to develop a transdisciplinary dynamic framework, grounded in a system-based approach, for research on determinants of sedentary behaviour across the life span and intervention and policy planning and evaluation. Methods: A comprehensive concept mapping approach was used to develop the Systems Of Sedentary behaviours (SOS) framework, involving four main phases: (1) preparation, (2) generation of statements, (3) structuring (sorting and ranking), and (4) analysis and interpretation. The first two phases were undertaken between December 2013 and February 2015 by the DEDIPAC KH team (DEterminants of DIet and Physical Activity Knowledge Hub). The last two phases were completed during a two-day consensus meeting in June 2015. Results: During the first phase, 550 factors regarding sedentary behaviour were listed across three age groups (i.e., youths, adults and older adults), which were reduced to a final list of 190 life course factors in phase 2 used during the consensus meeting. In total, 69 international delegates, seven invited experts and one concept mapping consultant attended the consensus meeting. The final framework obtained during that meeting consisted of six clusters of determinants: Physical Health and Wellbeing (71 % consensus), Social and Cultural Context (59 % consensus), Built and Natural Environment (65 % consensus), Psychology and Behaviour (80 % consensus), Politics and Economics (78 % consensus), and Institutional and Home Settings (78 % consensus). Conducting studies on Institutional Settings was ranked as the first research priority. The view that this framework captures a system-based map of determinants of sedentary behaviour was expressed by 89 % of the participants. Conclusion: Through an international transdisciplinary consensus process, the SOS framework was developed for the determinants of sedentary behaviour through the life course. Investigating the influence of Institutional and Home Settings was deemed to be the most important area of research to focus on at present and potentially the most modifiable. The SOS framework can be used as an important tool to prioritise future research and to develop policies to reduce sedentary time

Self-reported and objectively measured exposure to intervention content by intervention group and differences between intervention groups.

<p>GI = general information; SD = standard deviation; N = number of adolescents; k = number of classes;</p>†<p>based on one-way ANOVA;</p>‡<p>based on chi-square tests.</p

Baseline class and adolescent characteristics of adolescents in complete case analyses for the YouRAction, YouRAction+e, GI and total group.

<p>SD = standard deviation; GI = general information;</p><p>* = p<0.05; derived from multinomial regression analyses.</p

Appreciation of YouRAction, YouRAction+e and GI reported by adolescents who at least used the intervention once and differences between intervention groups.

<p>GI = general information; SD = standard deviation; N = number of adolescents; k = number of classes;</p>†<p>5 point scale (1–5);</p>‡<p>based on one-way ANOVA;</p>§<p>based on chi-square tests.</p

Baseline and six month post intervention compliance with the MVPA guideline and unstandardized regression coefficients of the effects of YouRAction vs GI stratified for adolescents with a Western or non-Western ethnic background.

<p>GI = general information; CI = confidence intervals; N = number of adolescents; k = number of classes;</p>†<p>multilevel linear or logistic regression analyses with class and individual as levels, adjusted for level of education;</p><p>* = p<0.05.</p

Flow diagram of the selection and enrolment of the study participants.

<p>Flow diagram of the selection and enrolment of the study participants.</p

The distribution (%) of sitting time across the original response options, for all countries combined.

<p>The distribution (%) of sitting time across the original response options, for all countries combined.</p

Sample characteristics, median sitting time per day, and prevalence of sitting more than 7.5 hours per day, by country and socio-demographic characteristics.

<p>Sample characteristics, median sitting time per day, and prevalence of sitting more than 7.5 hours per day, by country and socio-demographic characteristics.</p

The response rate of the Eurobarometer survey per country.

<p>The response rate of the Eurobarometer survey per country.</p