Mathematical Models of Nonlinear Effects in Asymmetric Catalysis:  New Insights Based on the Role of Reaction Rate

1997 ◽  
Vol 119 (52) ◽  
pp. 12934-12939 ◽  
Author(s):  
Donna G. Blackmond
Keyword(s):  
Mathematical Models ◽  
Asymmetric Catalysis ◽  
Reaction Rate ◽  
Nonlinear Effects

Pieces of Mind

2018 ◽  
Author(s):  
Carrie Figdor
Keyword(s):  
Mathematical Models ◽  
Moral Status ◽  
Entire Range ◽  
Fruit Flies ◽  
Literal Interpretation ◽  
Psychological Capacities

Many people accept that chimpanzees, dolphins, and some other animals can think and feel. But these cases are just the tip of a growing iceberg. If biologists are right, fruit flies and plants make decisions, worms and honeybees can be trained, bacteria communicate linguistically, and neurons have preferences. Just how far does cognition go? This book is the first to critically consider this question from the perspective of the entire range of new ascriptions of psychological capacities throughout biology. It is also the first to consider the role of mathematical models and other quantitative forms of evidence in prompting and supporting the new ascriptions. It defends a default literal interpretation of psychological terms across biological domains. It also considers the implications of the literal view for efforts to explain the mind’s place in nature and for traditional ways of distinguishing the superior moral status of humans relative to other living beings.

scholarly journals Simple mathematical models for controlling COVID-19 transmission through social distancing and community awareness

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ahmed S. Elgazzar
Keyword(s):  
Mathematical Models ◽  
Virus Transmission ◽  
Small World ◽  
Vaccination Rate ◽  
The Novel ◽  
Social Distancing ◽  
Community Awareness ◽  
Sufficient Degree ◽  
And Control

Abstract The novel COVID-19 pandemic is a current, major global health threat. Up till now, there is no fully approved pharmacological treatment or a vaccine. Also, its origin is still mysterious. In this study, simple mathematical models were employed to examine the dynamics of transmission and control of COVID-19 taking into consideration social distancing and community awareness. Both situations of homogeneous and nonhomogeneous population were considered. Based on the calculations, a sufficient degree of social distancing based on its reproductive ratio is found to be effective in controlling COVID-19, even in the absence of a vaccine. With a vaccine, social distancing minimizes the sufficient vaccination rate to control the disease. Community awareness also has a great impact in eradicating the virus transmission. The model is simulated on small-world networks and the role of social distancing in controlling the infection is explained.

Simulations of electric field at the initiation altitudes of sprites and halos generated by the thundercloud charge structure and lightning channels of causative return strokes

2021 ◽  
Author(s):  
Petr Kaspar ◽  
Ivana Kolmasova ◽  
Ondrej Santolik ◽  
Martin Popek ◽  
Pavel Spurny ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Boundary Conditions ◽  
Free Space ◽  
Nonlinear Effects ◽  
Charge Structure ◽  
Transient Luminous Events ◽  
Lightning Channel ◽  
Free Parameters

<p><span>Sprites and halos are transient luminous events occurring above thunderclouds. They can be observed simultaneously or they can also appear individually. Circumstances leading to initiation of these events are still not completely understood. In order to clarify the role of lightning channels of causative lightning return strokes and the corresponding thundercloud charge structure, we have developed a new model of electric field amplitudes at halo/sprite altitudes. It consists of electrostatic and inductive components of the electromagnetic field generated by the lightning channel in free space at a height of 15 km. Above this altitude we solve Maxwell’s equations self-consistently including the nonlinear effects of heating and ionization/attachment of the electrons. At the same time, we investigate the role of a development of the thundercloud charge structure and related induced charges above the thundercloud. We show how these charges lead to the different distributions of the electric field at the initiation heights of the halos and sprites. We adjust free parameters of the model using observations of halos and sprites at the Nydek TLE observatory and using measurements of luminosity curves of the corresponding return strokes measured by an array of fast photometers. The latter measurements are also used to set the boundary conditions of the model.</span></p>

Nonlinear Effects in Asymmetric Catalysis

1994 ◽  
Vol 116 (21) ◽  
pp. 9430-9439 ◽  
Author(s):  
Denis Guillaneux ◽  
Shu-Hai Zhao ◽  
Odile Samuel ◽  
David Rainford ◽  
Henri B. Kagan
Keyword(s):  
Asymmetric Catalysis ◽  
Nonlinear Effects

scholarly journals The role of mathematical models and scoring systems in detecting dysgerminoma in a young patient

2016 ◽  
Vol 87 (9) ◽  
pp. 675-675
Author(s):  
Nabil Abdalla ◽  
Joanna Winiarek ◽  
Agnieszka Timorek ◽  
Wlodzimierz Sawicki ◽  
Krzysztof Cendrowski
Keyword(s):  
Mathematical Models ◽  
Young Patient ◽  
Scoring Systems

scholarly journals Intracellular coupling modulates biflagellar synchrony

2021 ◽  
Vol 18 (174) ◽  
pp. 20200660
Author(s):  
Hanliang Guo ◽  
Yi Man ◽  
Kirsty Y. Wan ◽  
Eva Kanso
Keyword(s):  
Mathematical Models ◽  
Activity Level ◽  
Live Cells ◽  
Basal Bodies ◽  
Slip Mode ◽  
Biological Parameters ◽  
Hydrodynamic Coupling ◽  
Dimensionless Ratio ◽  
The Individual

Beating flagella exhibit a variety of synchronization modes. This synchrony has long been attributed to hydrodynamic coupling between the flagella. However, recent work with flagellated algae indicates that a mechanism internal to the cell, through the contractile fibres connecting the flagella basal bodies, must be at play to actively modulate flagellar synchrony. Exactly how basal coupling mediates flagellar coordination remains unclear. Here, we examine the role of basal coupling in the synchronization of the model biflagellate Chlamydomonas reinhardtii using a series of mathematical models of decreasing levels of complexity. We report that basal coupling is sufficient to achieve inphase, antiphase and bistable synchrony, even in the absence of hydrodynamic coupling and flagellar compliance. These modes can be reached by modulating the activity level of the individual flagella or the strength of the basal coupling. We observe a slip mode when allowing for differential flagellar activity, just as in experiments with live cells. We introduce a dimensionless ratio of flagellar activity to basal coupling that is predictive of the mode of synchrony. This ratio allows us to query biological parameters which are not yet directly measurable experimentally. Our work shows a concrete route for cells to actively control the synchronization of their flagella.

Mathematical Modeling of Supply Chain Management Systems

2010 ◽  
pp. 344-357
Author(s):  
N. Anbazhagan
Keyword(s):  
Mathematical Modeling ◽  
Supply Chain ◽  
Supply Chain Management ◽  
Mathematical Models ◽  
Stochastic Models ◽  
Management System ◽  
Raw Materials ◽  
Chain Management ◽  
Supply Chain Management System

Supply Chain Management (SCM) is the practice of coordinating the flow of goods, services, information and finances as they move from raw materials to parts supplier to manufacturer to wholesaler to retailer to consumer. Different supply chains have been designed for a variety of firms and this chapter discusses some issues in this regard. This chapter attempts to find why we require different supply chain for different companies. In this chapter we discuss the role of stochastic models in supply chain management system, and also discuss other mathematical models for SCM.

Migration from plastic packages into their contents. I. The role of mathematical models

1995 ◽  
Vol 350 (1694) ◽  
pp. 379-406 ◽  
Keyword(s):  
Mass Transfer ◽  
Mathematical Models ◽  
Diffusion Coefficients ◽  
Unit Area ◽  
Detailed Examination ◽  
Diffusion Equations ◽  
Legal Regulations ◽  
Successful Model ◽  
Plastic Packages

Materials contained in plastic packages can transfer (migrate) into the contents. In some circumstances, such as packages of food, drink or medicine, the consequences of this migration can be unpleasant or even harmful. Many countries, and the European Community, have adopted legal regulations designed to limit the amount of migration. It is shown, partly by discussing one example in some detail, that certain quantitative criteria in such regulations are unsatisfactory. The reasons include ( a ) improper recognition of the importance of package geometry, ( b ) invalid assumptions about a correspondence between concentrations in the contents and mass transfer per unit area of the package-contents interface and ( c ) failure to account, in an adequate manner, for the inevitable variability between nominally identical package systems. The principal theme of the paper is that these faults could have been, and can be, substantially ameliorated by proper use of mathematical models. Common shortcomings in the previous (but very limited) use of mathematics are exposed partly by detailed examination of a recent research paper. The paper discusses the requirements of a successful model and considers the simplest type, namely diffusion equations with diffusion coefficients that are independent of the concentrations of the migrant in either the plastic or the contents. Particular solutions are chosen to illustrate faults in existing legislation and practice, and because they are thought to be good candidates for testing against data. It is argued that future experiments would be more successful and more useful if they were planned and conducted in teams involving mathematicians.

Strange Attractors and Chaos in Nonlinear Mechanics

1983 ◽  
Vol 50 (4b) ◽  
pp. 1021-1032 ◽  
Author(s):  
P. J. Holmes ◽  
F. C. Moon
Keyword(s):  
Mathematical Models ◽  
Initial Conditions ◽  
Piecewise Linear ◽  
Nonlinear Differential Equations ◽  
Homoclinic Orbits ◽  
Strange Attractors ◽  
Electrical Systems ◽  
Nonlinear Mechanical ◽  
Sensitive Dependence

We review several examples of nonlinear mechanical and electrical systems and related mathematical models that display chaotic dynamics or strange attractors. Some simple mathematical models — iterated piecewise linear mappings — are introduced to explain and illustrate the concepts of sensitive dependence on initial conditions and chaos. In particular, we describe the role of homoclinic orbits and the horseshoe map in the generation of chaos, and indicate how the existence of such features can be detected in specific nonlinear differential equations.

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