scholarly journals A Stochastic Cobweb Dynamical Model

2008 ◽  
Vol 2008 ◽  
pp. 1-18 ◽  
Author(s):  
Serena Brianzoni ◽  
Cristiana Mammana ◽  
Elisabetta Michetti ◽  
Francesco Zirilli
Keyword(s):  
Dynamical System ◽  
Markov Chain ◽  
Random Variable ◽  
Asymptotically Stable ◽  
Stochastic Dynamical System ◽  
Cobweb Model ◽  
Linear Demand ◽  
Discrete Values ◽  
Analytical Tools

We consider the dynamics of a stochastic cobweb model with linear demand and a backward-bending supply curve. In our model, forward-looking expectations and backward-looking ones are assumed, in fact we assume that the representative agent chooses the backward predictor with probability , and the forward predictor with probability , so that the expected price at time is a random variable and consequently the dynamics describing the price evolution in time is governed by a stochastic dynamical system. The dynamical system becomes a Markov process when the memory rate vanishes. In particular, we study the Markov chain in the cases of discrete and continuous time. Using a mixture of analytical tools and numerical methods, we show that, when prices take discrete values, the corresponding Markov chain is asymptotically stable. In the case with continuous prices and nonnecessarily zero memory rate, numerical evidence of bounded price oscillations is shown. The role of the memory rate is studied through numerical experiments, this study confirms the stabilizing effects of the presence of resistant memory.

scholarly journals Fixed points and stability of A class of Stochastic dynamical system driven by Brownian motion

2021 ◽  
Vol 2087 (1) ◽  
pp. 012052
Author(s):  
Chun-Sheng Wang ◽  
Hong Ding ◽  
Ouyang Tong
Keyword(s):  
Dynamical System ◽  
Brownian Motion ◽  
Necessary Conditions ◽  
Real Life ◽  
Zero Solution ◽  
Fixed Point Method ◽  
Asymptotically Stable ◽  
Mean Square ◽  
Stochastic Dynamical System ◽  
Stability In Mean Square

Abstract In real life, many models and systems are affected by random phenomena. For this reason, experts and scholars propose to describe these stochastic processes with Brownian motion respectively. In this paper we consider a kind of stochastic Vollterra dynamical systems of nonconvolution type and give some new conditions to ensure that the zero solution is asymptotically stable in mean square by means of fixed point method. The theorems of asymptotically stability in mean square with a necessary conditions are proved. Some results of related papers are improved.

scholarly journals Using Social Media in Tourist Sentiment Analysis: A Case Study of Andalusia during the Covid-19 Pandemic

2021 ◽  
Vol 13 (7) ◽  
pp. 3836
Author(s):  
David Flores-Ruiz ◽  
Adolfo Elizondo-Salto ◽  
María de la O. Barroso-González
Keyword(s):  
Social Media ◽  
Sentiment Analysis ◽  
Cost Savings ◽  
Mass Scale ◽  
Tourism Sector ◽  
The Social ◽  
Analytical Tools ◽  
Media Data

This paper explores the role of social media in tourist sentiment analysis. To do this, it describes previous studies that have carried out tourist sentiment analysis using social media data, before analyzing changes in tourists’ sentiments and behaviors during the COVID-19 pandemic. In the case study, which focuses on Andalusia, the changes experienced by the tourism sector in the southern Spanish region as a result of the COVID-19 pandemic are assessed using the Andalusian Tourism Situation Survey (ECTA). This information is then compared with data obtained from a sentiment analysis based on the social network Twitter. On the basis of this comparative analysis, the paper concludes that it is possible to identify and classify tourists’ perceptions using sentiment analysis on a mass scale with the help of statistical software (RStudio and Knime). The sentiment analysis using Twitter data correlates with and is supplemented by information from the ECTA survey, with both analyses showing that tourists placed greater value on safety and preferred to travel individually to nearby, less crowded destinations since the pandemic began. Of the two analytical tools, sentiment analysis can be carried out on social media on a continuous basis and offers cost savings.

scholarly journals Elucidating the Complex Interactions between Stress and Epileptogenic Pathways

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Aaron R. Friedman ◽  
Luisa P. Cacheaux ◽  
Sebastian Ivens ◽  
Daniela Kaufer
Keyword(s):  
Experimental Data ◽  
Blood Brain Barrier ◽  
Inflammatory Cytokine ◽  
Stress Hormones ◽  
Brain Barrier ◽  
Barrier Dysfunction ◽  
Complex Interactions ◽  
Narrow Focus ◽  
Analytical Tools

Clinical and experimental data suggest that stress contributes to the pathology of epilepsy. We review mechanisms by which stress, primarily via stress hormones, may exacerbate epilepsy, focusing on the intersection between stress-induced pathways and the progression of pathological events that occur before, during, and after the onset of epileptogenesis. In addition to this temporal nuance, we discuss other complexities in stress-epilepsy interactions, including the role of blood-brain barrier dysfunction, neuron-glia interactions, and inflammatory/cytokine pathways that may be protective or damaging depending on context. We advocate the use of global analytical tools, such as microarray, in support of a shift away from a narrow focus on seizures and towards profiling the complex, early process of epileptogenesis, in which multiple pathways may interact to dictate the ultimate onset of chronic, recurring seizures.

New Directions in the Study of Institutional Logics: From Tools to Phenomena

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Michael Lounsbury ◽  
Christopher W.J. Steele ◽  
Milo Shaoqing Wang ◽  
Madeline Toubiana
Keyword(s):  
Recent Work ◽  
Online Publication ◽  
Institutional Logics ◽  
Annual Review ◽  
Publication Date ◽  
Complex Dynamic ◽  
New Directions ◽  
Analytical Tools ◽  
Dynamic Phenomena

In this article, we take stock of the institutional logics perspective and highlight opportunities for new scholarship. While we celebrate the growth and generativity of the literature on institutional logics, we also note that there has been a troubling tendency in recent work to use logics as analytical tools, feeding disquiet about reification and reductionism. Seeding a broader scholarly agenda that addresses such weaknesses in the literature, we highlight nascent efforts that aim to more systematically understand institutional logics as complex, dynamic phenomena in their own right. In doing so, we argue for more research that probes how logics cohere and endure by unpacking the role of values, the centrality of practice, and the governance dynamics of institutional logics and their orders. Furthermore, we encourage bridging the study of institutional logics with various literatures, including ethnomethodology, phenomenology, professions, elites, world society, and the old institutionalism, to enhance progress in these directions. Expected final online publication date for the Annual Review of Sociology, Volume 47 is July 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A comparative Study in the Role of Private Sector in Relationships Analysis between Economic Sustainability and COVID-19: Evidence from Iraq and Russia

2021 ◽  
Vol 39 (11) ◽  
Author(s):  
Ali Hazim Altameemi ◽  
Hakeem Hammood Flayyih
Keyword(s):  
Private Sector ◽  
Vaccination Campaign ◽  
Medium Size ◽  
Financial Leverage ◽  
Recovery Strategies ◽  
Production And Distribution ◽  
Twin Crisis ◽  
Analytical Tools ◽  
Global Health Problem

The study is designed to investigate the effect of the twin crisis on the private sector and national outlook of the oil dependent nations of Iraq and Russia. It is specifically aimed to evaluate and compare the recovery strategies put in place to survive the small and medium size enterprise. It is also of specific concern to estimate the end to pressure on this sector resulting from the global health problem. Descriptive and comparative research methods forms the central analytical tools employed to synthesis the research dilemma. A year sample t-test is used to compare the level of pressure on the private sector, recovery strategies, it results, performance of other sectors and macroeconomic performance proxies. As members of Organization of Petroleum Export Countries, Iraq and Russia private sector under performed in 2020. The t-statistic results confirm no significant mean difference in the effect of the 2020 twin crisis on private sector of both nations. However, the findings noted COVID-19 rules abiding (high stringency index) and financial leverage aim to support the agro-sector as the Iraqi economy resilient strategies. Russia though with increase financial leverage, focuses on vaccine production and distribution. It is for this reason that the t-statistic noted a significant different in recovery/infected between both nations. Russia should endeavor to improve its stringency index while furthering its vaccination efforts. Iraq needs to engage more vaccination campaign while keeping an eye on it agro sector.

Energy and Climate Planning: The Role of Analytical Tools and Soft Measures

2017 ◽  
pp. 13-47
Author(s):  
Carmelina Cosmi ◽  
Monica Salvia ◽  
Filomena Pietrapertosa ◽  
Senatro Di Leo
Keyword(s):  
Analytical Tools

scholarly journals Melatonin in yeast and fermented beverages: analytical tools for detection, physiological role and biosynthesis

2020 ◽  
Vol 3 (2) ◽  
pp. 144-160 ◽  
Author(s):  
Sara Muñiz-Calvo ◽  
Ricardo Bisquert ◽  
José M. Guillamón
Keyword(s):  
Biosynthetic Pathway ◽  
Physiological Role ◽  
Aromatic Amino Acids ◽  
Bioactive Molecules ◽  
Research Topics ◽  
Fermented Beverages ◽  
Potential Benefits ◽  
Analytical Tools ◽  
Melatonin Production

The recently established relation between the metabolism of aromatic amino acids of yeast and the production of different bioactive molecules during fermentation opens up new and interesting research topics. Among these molecules, melatonin has drawn researchers’ attention in the last decade given its potential benefits for human health. This review summarizes melatonin production in fermented beverages, and conventional and current methods for detecting melatonin in yeast-derived samples. In addition, the role of melatonin in yeast is discussed and the biosynthetic pathway of melatonin is presented in Saccharomyces cerevisiae.

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