Search

The COVID19 pandemic is generating an international effort to know the main dynamic aspects that this new epidemic crisis is causing, which is why a large number of initiatives are emerging around the world in relation to the development of mathematical models. The present work develops a dynamic simulation model based on the Systems Dynamics technique, under a systemic vision approach of the social and health problems it raises. The results have been simulated with respect to the casuistry of the Community of Madrid. The tremendous problem posed by the group of undetected infected, the cause of the spread of the epidemic, as well as the evidence of the technical difficulty posed by the lack of reliability of official data, for this reason, is evident. [ABSTRACT FROM AUTHOR]

Summary: This review summarises recent progress in understanding crassulacean acid metabolism (CAM) systems and the integration of internal and external stimuli to maximise water‐use efficiency. Complex CAM traits have been reduced to their minimum and captured as computational models, which can now be refined using recently available data from transgenic manipulations and large‐scale omics studies. We identify three key areas in which an appropriate choice of modelling tool could help capture relevant comparative molecular data to address the evolutionary drivers and plasticity of CAM. One focus is to identify the environmental and internal signals that drive inverse stomatal opening at night. Secondly, it is important to identify the regulatory processes required to orchestrate the diel pattern of carbon fluxes within mesophyll layers. Finally, the limitations imposed by contrasting succulent systems and associated hydraulic conductance components should be compared in the context of water‐use and evolutionary strategies. While network analysis of transcriptomic data can provide insights via co‐expression modules and hubs, alternative forms of computational modelling should be used iteratively to define the physiological significance of key components and informing targeted functional gene manipulation studies. We conclude that the resultant improvements of bottom‐up, mechanistic modelling systems can enhance progress towards capturing the physiological controls for phylogenetically diverse CAM systems in the face of the recent surge of information in this omics era. Significance Statement: We identify three key areas of crassulacean acid metabolism (CAM) physiology (stomata, mesophyll metabolism and hydraulic processes) which have been captured by current mathematical models and identify the additional molecular resources by which these modelling systems could be refined to enhance progress towards capturing the physiological controls of CAM systems in the face of the recent surge of 'omics' information. [ABSTRACT FROM AUTHOR]

The present study aims to identify and assess the parameters affecting agent behaviors and to simulate their effects on groundwater resources under the existing water regulations and policies. For this purpose, agent-based models are exploited to simulate the different groups of agents including Regional Water Authority, Public Prosecutor's Office, and the stakeholders as well as their interactions. The systems dynamic model is employed to investigate the effects of changes in agent behaviors on groundwater resources. The Any Logic software package is also used as a powerful tool for simulating both models and identifying the relationships between human behavior and water resources. Two efficient and inefficient scenarios are defined for assessing the effects of such parameters as ‘meetings of regional water agencies held with other public organizations”. Results revealed that changes in the behavior and interactions of Regional Water Authority with other public organizations under the first (inefficient) scenario led to increased renewable storage by 11.6 MCM while elimination of this parameter in the second (efficient) scenario led to a decrease of 52.6 MCM in renewable storage. Results of both scenarios showed that proper interactions of the Regional Water Authority with other stakeholders led to the control of illegal water abstractions and the rise of water table in the aquifers from the scenario one 1777.4 m–1778.1 m under the second scenario. [ABSTRACT FROM AUTHOR]

This article provides an estimation of the future demand of construction materials in Colombia and necessary minerals to produce them by using systems dynamic and analysis of materials flows. Through the analysis of materials flows the amount of minerals required for the production of cement and concrete are determined. Required production of cement and concrete is estimated through a model of systems dynamic, which is adjusted with data from DANE construction census. Results indicate that, disregarding the secondary offer of materials, 176.9 million tons of ground aggregates, river sand, gray cement, dead rock, and cooked ceramic would be required. Manufacture of cement and concrete would require 15.4 million tons of lime, 14.9 million tons of gravel, 14.1 million tons of gypsum, and 13.3, 9.7, and 9.3 million tons of clay, iron minerals, and sand, respectively. [ABSTRACT FROM AUTHOR]

The industrial sector is the largest consumer of energy in the world. In this sector, non-energy intensive companies have untapped energy efficiency potential, such as Uninterruptible Power Supply (UPS) manufacturers. Among the companies classified as non-energy-intensive, the International Energy Agency estimates that the untapped potential for energy efficiency is equivalent to the energy consumption of Japan and South Korea per year, together. In the literature, this unexplored potential is termed as a gap in energy management. The approaches found in the literature present a scenario where most companies exclusively use financial indicators to evaluate investment in energy efficiency. However, even if the results of these indicators are financially attractive, the level of adoption of energy efficiency technologies remains low. Studies on this unexplored potential present technological vies and do not contemplate conjuncture risks and uncertainties that may influence in the adoption of a technological solution. This study aims to analyze through practical application the systemic viability of the combined use of regenerative converters and energy storage in a UPS manufacturer, as well as the use of renewable energy sources for self-generation. The variables were identified through an SLR and combined into a closed loop diagram. A conceptual model was structured by representing the dynamic relationships between variables and the behavior of these variables in decisions related to energy efficiency. Systems Dynamic Modeling (SDM) was used to simulate the behavior of systems in different scenarios considering the use of such technologies and possible variations in energy supply and demand. The estimated financial results of each scenario are presented taking into account the assumptions of a computational model. The results of the model suggest that the use of Regenerative Converter Pulse Width Modulation (RC-PWM) is positive in any context, presenting ROI higher than 4 in the Red Rate Flag scenarios. The option for Distributed Microgeneration (DMG) exerts a negative influence on financial attractiveness, especially in the option of trading energy in a free environment. Government incentives and Peak Shaving (PS) have had a low influence on financial attractiveness for over 10 years. The developed model can be used to visualize alternatives and make decisions in similar situations. • A model to visualize the combined use of regenerative converters and energy storage is proposed. • The model developed focuses on productive systems. • The model proposed has proven, to be effective in practice. [ABSTRACT FROM AUTHOR]