In the article entitled "Analysis of the effect of acceleration in the Sunday models", the authors focused their attention on the dynamic models due to the possibilities offered by them to make precise analyzes on the evolution of a dependent variable due to the influences that the independent variables have on them. Analyzing the nature of these influences, we found that there is the prospect of accelerated evolution of these variables. At the macroeconomic level, in order to realize the forecasts of certain economic phenomena that influence the evolutions of the different states, we can use for a performance analysis the model of the accelerator without cycle, which due to its properties can give a realistic perspective on the tendency of the system evolution. Starting from the use of the term cyclicality, which characterizes the evolution of the various economic phenomena in one way or another depending on the various elements that determine this evolution, the authors will use it in this sense, in analyzing the accelerator of the dynamic models. Following this construction, the harmonized cycle accelerator model will take into account the fact that there must be such a correlation of the acceleration application in one direction or another. For example, if we take into account the problem of diminishing consumption in the national economy, we consider that a measure of negative acceleration must be taken in order to reduce it. At the same time, an increase in investments is needed, which implies the use of a harmonized cycle accelerator model, given that the measure aims at both an increase and a decrease, which is constantly harmonized. In the economy, we encounter cases in which the evolutions have a very high intensity in a relatively short period of time, thus accelerating, resulting in obtaining revenues well above the equilibrium aimed at maintaining macrostability, cases in which we will approach the accelerator model with explosive cycle. Considering the explosion, the accelerator is the one that leads to a special jump, evolving in its direction in both the positive and negative directions. The article also addresses other important issues such as the significance of these models, which in the authors' opinion should be considered as dynamic systems and which used in forecast models can manifest their influence in the right sense.

This research aims to measure the financial performance of companies in the water and sewerage sector by creating a sustainable econometric model for making long-term strategic decisions for managers and stakeholders. The research methodology consisted of the use and statistical processing of the data included in the summary financial statements of 40 regional operators in the field from 2014 to 2020. Multiple linear regression has been created with which stakeholders and water and sewerage specialists can shape changes in value-added variation, the average cost per employee, labor productivity, and energy expenditure on the net profit of water operators and sewerage. The results indicated that the independent variables used, such as value-added, labor productivity, or intangible assets have a direct influence on increasing the net profit of water and sewerage companies. Other independent variables such as the average cost per employee or the expenditure on electricity and water negatively influence the increase in the net profit of companies in the water and sewerage sector. The conclusions indicated that the average net profit is influenced by independent variables and the model created, and it can be successfully applied to other international companies in the field.