Review of the use of system dynamics (SD) in scrutinizing local energy transitions.

Local energy transition processes are complex socio-technical transitions requiring careful study. The use of System Dynamics (SD) in modelling and analyzing local energy transitions is especially suitable given the characteristics of SD. Our aim is to systematically categorize the different ways SD is used and useful to scrutinize local energy transitions, and to see if we can discern any common themes that can be useful to researchers looking to scrutinize local energy transitions, using SD. The study is exploratory in nature, with peer-reviewed journal and conference articles analyzed using content analysis. The six categories on which the articles are analyzed are: the sector the article studies; the transition that is studied in the article; the modelling depth in the article; the objective of the article; the justification for using SD provided in the article and the levels of interaction with 'local'. Our findings show most of the local energy transitions have been studied using simulatable Stock and Flow Diagrams in SD methodology. The important sectors in the energy field are represented in terms of SD modelling of local energy transitions, including electricity, transport, district heating etc. Most of the local energy transitions scrutinized by SD in the articles have descriptive objectives, with some prescriptive, and just one evaluative objective. In terms of justification for using SD provided by the articles analyzed in this study, we found four major themes along which the justifications that were provided. They are dynamics, feedbacks, delays and complexity, systematic thinking, bridging disciplines and actor interactions and behaviour. The 'dynamics, feedbacks, delays and complexity' theme is the most cited justification for the use of SD in scrutinizing local energy transitions, followed by systematic thinking.

Multi-model comparison of the economic and energy implications for China and India in an international climate regime.

This paper presents a modeling comparison on how stabilization of global climate change at about 2 °C above the pre-industrial level could affect economic and energy systems development in China and India. Seven General Equilibrium (CGE) and energy system models on either the global or national scale are soft-linked and harmonized with respect to population and economic assumptions. We simulate a climate regime, based on long-term convergence of per capita carbon dioxide (CO2) emissions, starting from the emission pledges presented in the Copenhagen Accord to the United Nations Framework Convention on Climate Change and allowing full emissions trading between countries. Under the climate regime, Indian emission allowances are allowed to grow more than the Chinese allowances, due to the per capita convergence rule and the higher population growth in India. Economic and energy implications not only differ among the two countries, but also across model types. Decreased energy intensity is the most important abatement approach in the CGE models, while decreased carbon intensity is most important in the energy system models. The reduction in carbon intensity is mostly achieved through deployment of carbon capture and storage, renewable energy sources and nuclear energy. The economic impacts are generally higher in China than in India, due to higher 2010-2050 cumulative abatement in China and the fact that India can offset more of its abatement cost though international emission trading.

Comparison of Polar® RS800CX heart rate monitor and electrocardiogram for measuring inter-beat intervals in healthy dogs.

UNLABELLED: The aim of the present study was to assess the criterion validity, relative reliability and level of agreement of Polar® RS800CX heart rate monitor measuring inter-beat intervals (IBIs), compared to simultaneously recorded electrocardiogram (ECG) in dogs. METHODS: Five continuous minutes of simultaneously recorded IBIs from Polar® RS800CX and Cardiostore ECG in 11 adult healthy dogs maintaining standing position were analyzed. Polar® data was statistically compared to ECG data to assess for systematic differences between the methods. Three different methods for handling missing IBI data were used. Criterion validities were calculated by intraclass correlation coefficients (ICCs) and corresponding 95% confidence intervals (CIs). Relative reliabilities and levels of agreement were calculated by ICCs and the Bland and Altman analysis for repeated measurements per subject. RESULTS: Correlation coefficients between IBI data from ECG and Polar® RS800CX varied between 0.73 and 0.84 depending on how missing values were handled. Polar® was over- and underestimating IBI data compared to ECG. The mean difference in log transformed (base10) IBI data was 0.8%, and 93.2% of the values were within the limits of agreement. Internally excluding three subjects presenting IBI series containing more than 5% erroneous IBIs resulted in ICCs between 0.97 and 0.99. Bland and Altman analysis (n=8) showed mean difference was 1.8ms, and 98.5% of the IBI values were plotted inside limits of agreement. CONCLUSION: This study showed that Polar® systematically biased recorded IBI series and that it was fundamental to detect measurement errors. For Polar® RS800CX heart rate monitor to be used interchangeably to ECG, by showing excellent criterion validity and reliable IBI measures in group and individual samples, only less than 5% of artifacts could be accepted.

Validity and reliability of Polar® RS800CX heart rate monitor, measuring heart rate in dogs during standing position and at trot on a treadmill.

UNLABELLED: The aim of the present study was to assess criterion validity, and relative and absolute reliability of Polar® RS800CX heart rate monitor, compared to simultaneously recorded electrocardiogram (ECG) data, in measuring heart rate of dogs during standing position and at trot on a treadmill. METHODS: Heart beats from Polar® RS800CX and Cardiostore ECG were recorded simultaneously during seven continuous minutes in standing position and at trot, in 10 adult healthy dogs. Polar® data was statistically compared to ECG data for a variety of mean beats per minute (BPM), standard deviation and confidence interval. Criterion validity was calculated by Pearson product moment correlation method and intraclass correlation coefficient (ICC2.1). Relative and absolute reliability were calculated by ICC2.1, the Bland and Altman analysis and standard error of measurement (SEM and SEM%). RESULTS: The correlation, criterion validity, between Polar® and ECG data in standing position was r=0.99 (p<0.0005) and at trot r=0.97 (p<0.0005). Polar® data was not significantly different from ECG data. Mean difference between ECG and uncorrected Polar® data was -0.6 BPM in standing position and -0.6 BPM at trot. Polar® was over- and underestimating ECG data. SEM and SEM% in standing were ±2.6 BPM and 3.0%, at trot ±3.8 BPM and 3.1%, indicating that measurement errors were low. CONCLUSION: This study showed that the criterion validity and the instrument reliability were excellent in Polar® RS800CX heart rate measuring system. The equipment seemed to be valid and reliable in measuring BPM in the dogs studied during submaximal cardiovascular conditions such as in standing position and at trot on a treadmill.

Efficacy of enalapril for prevention of congestive heart failure in dogs with myxomatous valve disease and asymptomatic mitral regurgitation.

We evaluated the long-term effect of early angiotensin-converting enzyme (ACE) inhibition (enalapril maleate) as monotherapy to postpone or prevent congestive heart failure (CHF) in asymptomatic dogs with mitral regurgitation (MR) attributable to myxomatous valvular disease (MVD) in a prospective, randomized, double-blinded, placebo-controlled multicenter trial involving 14 centers in Scandinavia. Two hundred twenty-nine Cavalier King Charles (CKC) Spaniels with MR attributable to MVD but no signs of CHF were randomly allocated to treatment with enalapril 0.25-0.5 mg daily (n = 116) or to placebo groups (n = 113). Each dog was evaluated by physical examination, electrocardiography, and thoracic radiography at entry and every 12 months (+/-30 days). The number of dogs developing heart failure was similar in the treatment and placebo groups (n = 50 [43%] and n = 48 [42%], respectively; P = .99). The estimated means, adjusted for censored observations, for the period from initiation of therapy to heart failure were 1,150 +/- 50 days for dogs in the treatment group and 1,130 +/- 50 days for dogs in the placebo group (P = .85). When absence or presence of cardiomegaly at the entrance of the trial was considered, there were still no differences between the treatment and placebo groups (P = .98 and .51, respectively). Multivariate analysis showed that enalapril had no significant effect on the time from initiation of therapy to heart failure (P = .86). Long-term treatment with enalapril in asymptomatic dogs with MVD and MR did not delay the onset of heart failure regardless of whether or not cardiomegaly was present at initiation of the study.