scholarly journals On the global dynamics of the anisotropic Manev problem

2004 ◽  
Vol 194 (1-2) ◽  
pp. 75-94 ◽  
Author(s):  
Florin Diacu ◽  
Manuele Santoprete
Keyword(s):  
Global Dynamics ◽  
Anisotropic Manev Problem

COVID-19 Pandemic: Experiences in China and Implications for its Prevention and Treatment Worldwide

2020 ◽  
Vol 20 (6) ◽  
pp. 410-416 ◽  
Author(s):  
Ning-Ning Liu ◽  
Jing-Cong Tan ◽  
Jingquan Li ◽  
Shenghui Li ◽  
Yong Cai ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
International Community ◽  
Disease Spread ◽  
Global Dynamics ◽  
The World ◽  
Prevention And Treatment ◽  
History Of

The outbreak of COVID-19 due to SARS-CoV-2 originally emerged in Wuhan in December 2019. As of March 22, 2020, the disease spread to 186 countries, with at least 305,275 confirmed cases. Although there has been a decline in the spread of the disease in China, the prevalence of COVID-19 around the world remains serious despite containment efforts undertaken by national authorities and the international community. In this article, we systematically review the brief history of COVID-19 and its epidemic and clinical characteristics, highlighting the strategies used to control and prevent the disease in China, which may help other countries respond to the outbreak. This pandemic emphasizes the need to be constantly alert to shifts in both the global dynamics and the contexts of individual countries, making sure that all are aware of which approaches are successful for the prevention, containment and treatment of new diseases, and being flexible enough to adapt the responses accordingly.

The global dynamics of stochastic Holling type II predator-prey models with non constant mortality rate

Filomat ◽  
2017 ◽  
Vol 31 (18) ◽  
pp. 5811-5825
Author(s):  
Xinhong Zhang
Keyword(s):  
Mortality Rate ◽  
Stochastic Model ◽  
Sufficient Conditions ◽  
Positive Periodic Solution ◽  
Global Dynamics ◽  
Type Ii ◽  
Predator Prey ◽  
Persistence In The Mean ◽  
The Mean ◽  
Predator Prey Models

In this paper we study the global dynamics of stochastic predator-prey models with non constant mortality rate and Holling type II response. Concretely, we establish sufficient conditions for the extinction and persistence in the mean of autonomous stochastic model and obtain a critical value between them. Then by constructing appropriate Lyapunov functions, we prove that there is a nontrivial positive periodic solution to the non-autonomous stochastic model. Finally, numerical examples are introduced to illustrate the results developed.

Researching the Localizations of the Global

2018 ◽  
pp. 72-92
Author(s):  
Saskia Sassen
Keyword(s):  
Global Dynamics ◽  
Data Sets ◽  
Global Studies ◽  
Research Techniques ◽  
The Creation

Although the global is often portrayed in opposition to the national, this chapter explores how the global can be structured inside the national in at least three ways that are significant for the field of global studies. They are a) the endogenizing or the localizing of global dynamics in the national milieu; b) the creation of formations that, although global, are articulated with particular actors, cultures, or projects; and c) the denationalizing of what had historically been constructed as national. Global studies research into such subnationally based processes and dynamics of globalization requires methodologies and theorizations that engage not only global scalings but also subnational scalings as components of global processes. It makes possible the use of long-standing research techniques in the study of globalization, and it provides a bridge between globalization and the wealth of national and subnational data sets.

scholarly journals Global dynamics of international migration systems across South–South, North–North, and North–South flows, 1990–2015

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Diego F. Leal ◽  
Nicolas L. Harder
Keyword(s):  
International Migration ◽  
Network Effects ◽  
Global Dynamics ◽  
Core Set ◽  
Migration Dynamics ◽  
Key Drivers ◽  
Migration Flows ◽  
And Migration ◽  
Migration Systems

AbstractEvidence from 184 countries over the span of 25 years is gathered and analyzed to understand North–North, South–South, and North–South international migration flows. Conceptually, the analysis borrows from network theory and Migration Systems Theory (MST) to develop a model to characterize the structure and evolution of international migration flows. Methodologically, the Stochastic Actor-oriented Model of network dynamics is used to jointly model the three types of flows under analysis. Results show that endogenous network effects at the monadic, dyadic, and triadic levels of analysis are relevant to understand the emergence and evolution of migration flows. The findings also show that a core set of non-network covariates, suggested by MST as key drivers of migration flows, does not always explain migration dynamics in the systems under analysis in a consistent fashion; thus, suggesting the existence of important levels of heterogeneity inherent to these three types of flows. Finally, evidence related to the role of political instability and countries’ care deficits is also discussed as part of the analysis. Overall, the results highlight the importance of analyzing flows across the globe beyond typically studied migratory corridors (e.g., North–South flows) or regions (e.g., Europe).

scholarly journals A Comparative Research Between Italian and Turkish Journalists: Professionalism, Autonomy, Clientelism, and Ethic

SAGE Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215824402110101
Author(s):  
Xheni Simaku
Keyword(s):  
Comparative Research ◽  
Global Dynamics ◽  
Global Society ◽  
Media And Politics ◽  
Media System ◽  
National Media ◽  
Media Systems ◽  
Depth Interviews ◽  
Cross National

The global society which we live in nowadays makes us rethink about media system, global dynamics, and the operation of the influences that these dynamics have on national media systems. Starting from the book by Hallin and Mancini’s (2004) Comparing Media Systems: Three Models of Media and Politics, and under the Polarized Pluralist Model they proposed, the aim of this work is to compare Turkish and Italian journalists’ professionalization. This research has been conducted under the concept of professionalization that these authors suggested in their work and, more specifically, under the Polarized Pluralist Model, in which Hallin and Mancini recognize countries like Italy have the main characteristics described by the model; Turkey can also be included. The main goal of this work is to underline not only the similarities but also the differences that are encountered in these two countries in the journalistic professionalization. The methodology used is in-depth interviews with 10 journalists: five Italian and five Turkish journalists chosen from the biggest journals in their respective countries. Main topics taken into consideration were autonomy, clientelism, and professionalization in journalism based on ethics values. Even if the Polarized Pluralist Model seems to fit in both countries from a macro perspective, with the in-depth interviews, it is clearly seen that different cross-national nuances come out.

scholarly journals Redshift-space effects in voids and their impact on cosmological tests. Part I: the void size function

2020 ◽  
Vol 500 (1) ◽  
pp. 911-925
Author(s):  
Carlos M Correa ◽  
Dante J Paz ◽  
Ariel G Sánchez ◽  
Andrés N Ruiz ◽  
Nelson D Padilla ◽  
...  
Keyword(s):  
Theoretical Framework ◽  
Real Space ◽  
Global Dynamics ◽  
Void Size ◽  
Spherical Void ◽  
Cosmological Constraints ◽  
Redshift Surveys ◽  
Size Function ◽  
Expansion Effect ◽  
Space Effects

ABSTRACT Voids are promising cosmological probes. Nevertheless, every cosmological test based on voids must necessarily employ methods to identify them in redshift space. Therefore, redshift-space distortions (RSD) and the Alcock–Paczyński effect (AP) have an impact on the void identification process itself generating distortion patterns in observations. Using a spherical void finder, we developed a statistical and theoretical framework to describe physically the connection between the identification in real and redshift space. We found that redshift-space voids above the shot noise level have a unique real-space counterpart spanning the same region of space, they are systematically bigger and their centres are preferentially shifted along the line of sight. The expansion effect is a by-product of RSD induced by tracer dynamics at scales around the void radius, whereas the off-centring effect constitutes a different class of RSD induced at larger scales by the global dynamics of the whole region containing the void. The volume of voids is also altered by the fiducial cosmology assumed to measure distances, this is the AP change of volume. These three systematics have an impact on cosmological statistics. In this work, we focus on the void size function. We developed a theoretical framework to model these effects and tested it with a numerical simulation, recovering the statistical properties of the abundance of voids in real space. This description depends strongly on cosmology. Hence, we lay the foundations for improvements in current models of the abundance of voids in order to obtain unbiased cosmological constraints from redshift surveys.

scholarly journals Threshold Dynamics in a Model for Zika Virus Disease with Seasonality

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
Mahmoud A. Ibrahim ◽  
Attila Dénes
Keyword(s):  
Zika Virus ◽  
Reproduction Number ◽  
Virus Disease ◽  
Threshold Dynamics ◽  
Global Dynamics ◽  
Threshold Parameter ◽  
Globally Asymptotically Stable ◽  
Linear Integral ◽  
The Impact ◽  
Disease Free

AbstractWe present a compartmental population model for the spread of Zika virus disease including sexual and vectorial transmission as well as asymptomatic carriers. We apply a non-autonomous model with time-dependent mosquito birth, death and biting rates to integrate the impact of the periodicity of weather on the spread of Zika. We define the basic reproduction number $${\mathscr {R}}_{0}$$ R 0 as the spectral radius of a linear integral operator and show that the global dynamics is determined by this threshold parameter: If $${\mathscr {R}}_0 < 1,$$ R 0 < 1 , then the disease-free periodic solution is globally asymptotically stable, while if $${\mathscr {R}}_0 > 1,$$ R 0 > 1 , then the disease persists. We show numerical examples to study what kind of parameter changes might lead to a periodic recurrence of Zika.

scholarly journals Global dynamics of a novel deterministic and stochastic SIR epidemic model with vertical transmission and media coverage

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Xiaodong Wang ◽  
Chunxia Wang ◽  
Kai Wang
Keyword(s):  
Vertical Transmission ◽  
Epidemic Model ◽  
Media Coverage ◽  
Existence And Uniqueness ◽  
Deterministic Model ◽  
Reproduction Number ◽  
Global Dynamics ◽  
Sir Epidemic Model ◽  
Sir Epidemic ◽  
Stochastic Sir

AbstractIn this paper, we study a novel deterministic and stochastic SIR epidemic model with vertical transmission and media coverage. For the deterministic model, we give the basic reproduction number $R_{0}$ R 0 which determines the extinction or prevalence of the disease. In addition, for the stochastic model, we prove existence and uniqueness of the positive solution, and extinction and persistence in mean. Furthermore, we give numerical simulations to verify our results.

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