BIFURCATIONS IN A FREQUENCY-WEIGHTED KURAMOTO OSCILLATORS NETWORK

2012 ◽  
Vol 22 (09) ◽  
pp. 1250230 ◽  
Author(s):  
HANQING WANG ◽  
XIANG LI
Keyword(s):  
Hopf Bifurcation ◽  
Human Population ◽  
Activity Patterns ◽  
Dimensional System ◽  
Human Beings ◽  
Saddle Node Bifurcation ◽  
Kuramoto Oscillators ◽  
Oscillator Network ◽  
The Rich ◽  
Low Dimensional

This paper focuses on the origin of rich dynamics in a frequency-weighted Kuramoto-oscillator network, which embeds the periodical activity patterns of human beings to understand the collective behaviorial dynamics in human population. We present analytical results of the dynamics of the model by reducing the N-dimensional system to solvable low-dimensional equations. The bifurcation analysis reveals that there exist supercritical Hopf bifurcation and infinite-period saddle-node bifurcation, which explain the rich dynamics including the incoherent, oscillatory, and synchronous states observed in this model.

Hopf Bifurcation Analysis and Stability for a Ratio-Dependent Predator–Prey Diffusive System with Time Delay

2020 ◽  
Vol 30 (03) ◽  
pp. 2050037
Author(s):  
Longyue Li ◽  
Yingying Mei ◽  
Jianzhi Cao
Keyword(s):  
Hopf Bifurcation ◽  
Time Delay ◽  
Periodic Solutions ◽  
Positive Equilibrium ◽  
Dimensional System ◽  
Normal Form Theory ◽  
Center Manifold Reduction ◽  
Predator Prey ◽  
Ratio Dependent ◽  
Low Dimensional

In this paper, we are focused on a new ratio-dependent predator–prey system that introduced the diffusive and time delay effect simultaneously. By analyzing the characteristic equations and the distribution of eigenvalues, we examine the stability and boundary of positive equilibrium states, and the existence of spatially homogeneous and spatially inhomogeneous bifurcating periodic solutions, respectively. Further, we prove that when [Formula: see text], the system has Hopf bifurcation at the positive equilibrium state. By using the center manifold reduction, we simplify the system so that we can convert an infinite-dimensional system into a low-dimensional finite-dimensional system. By using the normal form theory, we obtain explicit expressions for the direction, stability and period of Hopf bifurcation periodic solutions. Finally, we have illustrated the main results in this thesis by numerical examples, our work may provide some useful measures to save time or cost and to control the ecosystem.

Impact of Environmental Degradation on Human Health

2016 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
_______ Archana ◽  
Charu Datta ◽  
Pratibha Tiwari
Keyword(s):  
Environmental Degradation ◽  
Human Population ◽  
Environmental Problems ◽  
Population Increase ◽  
Human Beings ◽  
The People ◽  
Wide Range ◽  
Different Types ◽  
Economic Institute ◽  
Day By Day

Degradation of environment is one of the most serious challenges before the mankind in today’s world. Mankind has been facing a wide range of problem arising out of the degradation of environment. Not only the areas under human inhabitation, but the areas of the planet without human population have also been suffering from these problems. As the population increase day by day, the amenities are not improved simultaneously. With the advancement of science and technologies the needs of human beings has been changing rapidly. As a result different types of environmental problems have been rising. Environmental degradation is a wide- reaching problem and it is likely to influence the health of human population is great. It may be defined the deterioration of the environment through depletion of resources such as air, water, and soil. The destruction of ecosystem and extinction of wildlife. Environmental degradation has occurred due to the recent activities in the field of socio-economic, institute and technology. Poverty still remains a problem as the root of several environmental problems to create awareness among the people about the ill effect of environmental pollution. In the whole research it is clear that all factors of environmental degradation may be reduced through- Framing the new laws on environmental degradation, Environment friend policy, Controlling all the ways and means of noise, air, soil and water pollution, Through growing more and more trees and by adapting the proper sanitation policy.  

A Final Muse

2018 ◽  
Author(s):  
David Wendell Moller
Keyword(s):  
Human Beings ◽  
The Poor ◽  
The Rich

Why are kings without pity for their subjects? Because they count on never being common human beings. Why are the rich so hard toward the poor? It is because they have no fear of being poor. . . .—Jean-Jacques Rousseau, Émile; or, On Education1In Shakespeare’s ...

Improved interactive color visualization approach for hyperspectral images

2021 ◽  
pp. 147387162110481
Author(s):  
Haijun Yu ◽  
Shengyang Li
Keyword(s):  
Real Time ◽  
Hyperspectral Images ◽  
High Dimensional ◽  
Interactive Control ◽  
Output Image ◽  
Dr Method ◽  
The Rich ◽  
Low Dimensional ◽  
Color Visualization ◽  
Fusion Coefficient

Hyperspectral images (HSIs) have become increasingly prominent as they can maintain the subtle spectral differences of the imaged objects. Designing approaches and tools for analyzing HSIs presents a unique set of challenges due to their high-dimensional characteristics. An improved color visualization approach is proposed in this article to achieve communication between users and HSIs in the field of remote sensing. Under the real-time interactive control and color visualization, this approach can help users intuitively obtain the rich information hidden in original HSIs. Using the dimensionality reduction (DR) method based on band selection, high-dimensional HSIs are reduced to low-dimensional images. Through drop-down boxes, users can freely specify images that participate in the combination of RGB channels of the output image. Users can then interactively and independently set the fusion coefficient of each image within an interface based on concentric circles. At the same time, the output image will be calculated and visualized in real time, and the information it reflects will also be different. In this approach, channel combination and fusion coefficient setting are two independent processes, which allows users to interact more flexibly according to their needs. Furthermore, this approach is also applicable for interactive visualization of other types of multi-layer data.

scholarly journals Comparative Genomics ofH. pyloriand Non-PyloriHelicobacterSpecies to Identify New Regions Associated with Its Pathogenicity and Adaptability

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
De-Min Cao ◽  
Qun-Feng Lu ◽  
Song-Bo Li ◽  
Ju-Ping Wang ◽  
Yu-Li Chen ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Functional Annotation ◽  
Human Population ◽  
Large Scale ◽  
Bacterial Species ◽  
Human Beings ◽  
Gram Negative ◽  
Protein Protein Interaction ◽  
H Pylori ◽  
Cooperation Relationship

The genusHelicobacteris a group of Gram-negative, helical-shaped pathogens consisting of at least 36 bacterial species.Helicobacter pylori(H. pylori), infecting more than 50% of the human population, is considered as the major cause of gastritis, peptic ulcer, and gastric cancer. However, the genetic underpinnings ofH. pylorithat are responsible for its large scale epidemic and gastrointestinal environment adaption within human beings remain unclear. Core-pan genome analysis was performed among 75 representativeH. pyloriand 24 non-pylori Helicobactergenomes. There were 1173 conserved protein families ofH. pyloriand 673 of all 99Helicobactergenus strains. We found 79 genome unique regions, a total of 202,359bp, shared by at least 80% of theH. pyloribut lacked in non-pylori Helicobacterspecies. The operons, genes, and sRNAs within theH. pyloriunique regions were considered as potential ones associated with its pathogenicity and adaptability, and the relativity among them has been partially confirmed by functional annotation analysis. However, functions of at least 54 genes and 10 sRNAs were still unclear. Our analysis of protein-protein interaction showed that 30 genes within them may have the cooperation relationship.

scholarly journals Evidence accumulation and change rate inference in dynamic environments

2016 ◽  
Author(s):  
Adrian E Radillo ◽  
Alan Veliz-Cuba ◽  
Kresimir Josic ◽  
Zachary Kilpatrick
Keyword(s):  
Rate Of Change ◽  
Ideal Observer ◽  
Moment Closure ◽  
Dimensional System ◽  
Change Rate ◽  
Observer Model ◽  
Low Dimensional ◽  
State Of The Environment ◽  
Rate Correlation ◽  
Moment Closure Approximation

In a constantly changing world, animals must account for environmental volatility when making decisions. To appropriately discount older, irrelevant information, they need to learn the rate at which the environment changes. We develop an ideal observer model capable of inferring the present state of the environment along with its rate of change. Key to this computation is updating the posterior probability of all possible changepoint counts. This computation can be challenging, as the number of possibilities grows rapidly with time. However, we show how the computations can be simplified in the continuum limit by a moment closure approximation. The resulting low-dimensional system can be used to infer the environmental state and change rate with accuracy comparable to the ideal observer. The approximate computations can be performed by a neural network model via a rate-correlation based plasticity rule. We thus show how optimal observers accumulates evidence in changing environments, and map this computation to reduced models which perform inference using plausible neural mechanisms.

Non-Standard Reduction of Noisy Structural Systems: Shallow Arches

2000 ◽  
Author(s):  
Lalit Vedula ◽  
N. Sri Namachchivaya
Keyword(s):  
Markov Process ◽  
Random Perturbation ◽  
Exit Time ◽  
Stochastic Averaging ◽  
Dimensional System ◽  
Shallow Arches ◽  
Higher Dimensional ◽  
Mean Exit Time ◽  
Stationary Probability Density Function ◽  
Low Dimensional

Abstract The dynamics of a shallow arch subjected to small random external and parametric excitation is invegistated in this work. We develop rigorous methods to replace, in some limiting regime, the original higher dimensional system of equations by a simpler, constructive and rational approximation – a low-dimensional model of the dynamical system. To this end, we study the equations as a random perturbation of a two-dimensional Hamiltonian system. We achieve the model-reduction through stochastic averaging and the reduced Markov process takes its values on a graph with certain glueing conditions at the vertex of the graph. Examination of the reduced Markov process on the graph yields many important results such as mean exit time, stationary probability density function.

Lessons from Covid 19 experience for African governments: towards environmental sustainability

2020 ◽  
Vol 3 (3) ◽  
pp. 126-132
Author(s):  
Peter Bisong Bisong
Keyword(s):  
Global Warming ◽  
Environmental Sustainability ◽  
Human Population ◽  
Environmental Crisis ◽  
Human Beings ◽  
Life Changes ◽  
Philosophical Methods ◽  
Long Time

Covid 19 is an unfortunate situation that nevertheless could be said to have produced environmentally beneficial results. It has forced Africans and humanity in general to change attitudes and lifestyles that were hitherto inimical to the environment to ones that could restore the environment. For the sake of survival, consumerism which is one of the greatest hallmarks of Africans and a source of depletion of earth resources has given way to frugality; transportation activities that is one of the greatest sources of global warming have significantly reduced and most importantly human population which has terrifically posed as a threat to the survival of the environment is being forcefully checked. These and many other life changes in human beings, though accidental, are healing the environment, and the paper argues that if they are sustained, the environment will totally be restored to sound health. Most of these changes will naturally be sustained even after the Covid 19 pandemic, for as Aristotle acknowledged, actions perpetrated for a long time become habituated. However, I believe that if conscious efforts are also made to sustain these changed attitudes, then the environmental crisis currently enveloping the globe will be halted. The paper using philosophical methods of criticality and argumentation concludes that Covid 19 though tragic for humans, nevertheless has lessons that could be useful for the present drive to sustain the environment and by that prevent future pandemic that could be environmentally related. The paper argues vehemently that African governments must steer their developmental agenda towards environmental sustenance in line with Covid 19 seeming directives to humanity.

scholarly journals Observable for a Large System of Globally Coupled Excitable Units

2019 ◽  
Vol 24 (2) ◽  
pp. 37 ◽  
Author(s):  
Santiago Boari ◽  
Gonzalo Uribarri ◽  
Ana Amador ◽  
Gabriel Mindlin
Keyword(s):  
Order Parameter ◽  
Field Potential ◽  
Dimensional System ◽  
System Of Equations ◽  
In Vivo Electrophysiology ◽  
Excitable Systems ◽  
Global Variable ◽  
Good Proxy ◽  
Low Dimensional

The study of large arrays of coupled excitable systems has largely benefited from a technique proposed by Ott and Antonsen, which results in a low dimensional system of equations for the system’s order parameter. In this work, we show how to explicitly introduce a variable describing the global synaptic activation of the network into these family of models. This global variable is built by adding realistic synaptic time traces. We propose that this variable can, under certain conditions, be a good proxy for the local field potential of the network. We report experimental, in vivo, electrophysiology data supporting this claim.

Fear Induced Stabilization in an Intraguild Predation Model

2020 ◽  
Vol 30 (04) ◽  
pp. 2050053
Author(s):  
Mainul Hossain ◽  
Nikhil Pal ◽  
Sudip Samanta ◽  
Joydev Chattopadhyay
Keyword(s):  
Growth Rate ◽  
Hopf Bifurcation ◽  
Intraguild Predation ◽  
Equilibrium Points ◽  
Stable Limit ◽  
Interior Equilibrium ◽  
The Rich ◽  
The Stability ◽  
The Cost ◽  
The Impact

In the present paper, we investigate the impact of fear in an intraguild predation model. We consider that the growth rate of intraguild prey (IG prey) is reduced due to the cost of fear of intraguild predator (IG predator), and the growth rate of basal prey is suppressed due to the cost of fear of both the IG prey and the IG predator. The basic mathematical results such as positively invariant space, boundedness of the solutions, persistence of the system have been investigated. We further analyze the existence and local stability of the biologically feasible equilibrium points, and also study the Hopf-bifurcation analysis of the system with respect to the fear parameter. The direction of Hopf-bifurcation and the stability properties of the periodic solutions have also been investigated. We observe that in the absence of fear, omnivory produces chaos in a three-species food chain system. However, fear can stabilize the chaos thus obtained. We also observe that the system shows bistability behavior between IG prey free equilibrium and IG predator free equilibrium, and bistability between IG prey free equilibrium and interior equilibrium. Furthermore, we observe that for a suitable set of parameter values, the system may exhibit multiple stable limit cycles. We perform extensive numerical simulations to explore the rich dynamics of a simple intraguild predation model with fear effect.

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