scholarly journals Biological Invasion and Coexistence in Intraguild Predation

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Wenting Wang ◽  
Xiaoli Feng ◽  
Xiuping Chen
Keyword(s):  
Biological Invasion ◽  
Exotic Species ◽  
Intraguild Predation ◽  
Diffusion Reaction ◽  
Key Factors ◽  
First Case ◽  
Spatial Dimensions ◽  
The Common ◽  
Reaction Equations ◽  
High Asymmetry

Invasion of an exotic species initiated by its local introduction is considered subject to intraguild predation (IGP). Mathematically, the system dynamics is described by three nonlinear diffusion-reaction equations in two spatial dimensions. The key factors that determine successful invasion are investigated by means of extensive numerical simulations. The results reveal high asymmetry. An exotic species can invade successfully if it acted as the top predator and engaged in IGP, and the IGP interactions of the postinvasion web will be kept. While the exotic species were introduced as the intraguild prey (IGprey), they invade and spread through patchy invasion which corresponds to the invasion at the edge of extinction. Increase of the IGprey's dispersal rate and decrease of the IGpredator's may make the IGprey invade. But the interactions of the postinvasion web will change from IGP to competition, which is absolutely different from the first case. Finally, the common existence of IGP was explored once again from the perspective of biological invasion.

Solitary and Travelling Wave Solutions of Certain Nonlinear Diffusion-Reaction Equations

2020 ◽  
Author(s):  
Miftachul Hadi
Keyword(s):  
Nonlinear Diffusion ◽  
Travelling Wave ◽  
Diffusion Reaction ◽  
Travelling Wave Solutions ◽  
Wave Solutions ◽  
Reaction Equations

We review the work of Ranjit Kumar, R S Kaushal, Awadhesh Prasad. The work is still in progress.

scholarly journals On a Robust and Efficient Numerical Scheme for the Simulation of Stationary 3-Component Systems with Non-Negative Species-Concentration with an Application to the Cu Deposition from a Cu-(β-alanine)-Electrolyte

Algorithms ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 113
Author(s):  
Stephan Daniel Schwoebel ◽  
Thomas Mehner ◽  
Thomas Lampke
Keyword(s):  
Augmented Lagrangian ◽  
Computation Time ◽  
Species Distributions ◽  
Chemical Processes ◽  
Diffusion Reaction ◽  
Augmented Lagrangian Methods ◽  
Major Question ◽  
Component Systems ◽  
Reaction Models ◽  
Reaction Equations

Three-component systems of diffusion–reaction equations play a central role in the modelling and simulation of chemical processes in engineering, electro-chemistry, physical chemistry, biology, population dynamics, etc. A major question in the simulation of three-component systems is how to guarantee non-negative species distributions in the model and how to calculate them effectively. Current numerical methods to enforce non-negative species distributions tend to be cost-intensive in terms of computation time and they are not robust for big rate constants of the considered reaction. In this article, a method, as a combination of homotopy methods, modern augmented Lagrangian methods, and adaptive FEMs is outlined to obtain a robust and efficient method to simulate diffusion–reaction models with non-negative concentrations. Although in this paper the convergence analysis is not described rigorously, multiple numerical examples as well as an application to elctro-deposition from an aqueous Cu2+-(β-alanine) electrolyte are presented.

scholarly journals B.05 Hemi-laryngopharyngeal spasm (HELPS) syndrome: The discovery, cure, and characterization of a new neurological condition

2017 ◽  
Vol 44 (S2) ◽  
pp. S11-S11
Author(s):  
C Honey ◽  
M Morrison
Keyword(s):  
Surgical Care ◽  
Review Of The Literature ◽  
The Past ◽  
First Case ◽  
Patient Reported ◽  
Operative Outcome ◽  
Small Cohort ◽  
The Common ◽  
Similar Motor

Background: We published the world’s first case of hemi-laryngpharyngeal spasm (HELPS) syndrome cured by microvascular decompression (MVD) of the Xth cranial nerve in 2016. We now present a small cohort of patients (n=3) successfully treated with surgery in order to better delineate the common characteristics of this syndrome, diagnostic tests of choice, nuances of their surgical care and outcomes of their treatment. Methods: The history and physical examination of three patients with HELPS syndrome are presented. Pre-operative laryngoscopy, neuroimaging, response to botox and intra-operative videos are detailed. Post-operative outcome and complications are presented. Results: Each patient reported similar motor (choking) and sensory (coughing) features in their history. Episodic choking relentlessly progressed over the years until it occurred while sleeping and with frightening severity prompting tracheostomy in one patient and intubation in another. A “tickling” sensation deep in the throat triggered episodic coughing that worsened over the years until it occurred while sleeping and with frightening severity (syncope and incontinence). Conclusions: A review of the literature suggests that patients with similar symptoms, often called episodic laryngospasm in the past, have been treated with psychotherapy or antacids. With the recognition that a clearly defined subset of these patients have HELPS syndrome, we can offer them the potential of a neurosurgical cure.

scholarly journals Estimating the extent of glioblastoma invasion

2021 ◽  
Vol 82 (1-2) ◽  
Author(s):  
Christian Engwer ◽  
Michael Wenske
Keyword(s):  
Analytic Solution ◽  
Glioma Cells ◽  
Diffusion Reaction ◽  
Kpp Equation ◽  
Advection Diffusion ◽  
Clinical Interest ◽  
Inhomogeneous Diffusion ◽  
Reaction Equations ◽  
Advection Diffusion Reaction Equations ◽  
Tumor Extent

AbstractGlioblastoma Multiforme is a malignant brain tumor with poor prognosis. There have been numerous attempts to model the invasion of tumorous glioma cells via partial differential equations in the form of advection–diffusion–reaction equations. The patient-wise parametrization of these models, and their validation via experimental data has been found to be difficult, as time sequence measurements are mostly missing. Also the clinical interest lies in the actual (invisible) tumor extent for a particular MRI/DTI scan and not in a predictive estimate. Therefore we propose a stationalized approach to estimate the extent of glioblastoma (GBM) invasion at the time of a given MRI/DTI scan. The underlying dynamics can be derived from an instationary GBM model, falling into the wide class of advection-diffusion-reaction equations. The stationalization is introduced via an analytic solution of the Fisher-KPP equation, the simplest model in the considered model class. We investigate the applicability in 1D and 2D, in the presence of inhomogeneous diffusion coefficients and on a real 3D DTI-dataset.

scholarly journals Numerical Simulation of the Coagulation Dynamics of Blood

2008 ◽  
Vol 9 (2) ◽  
pp. 83-104 ◽  
Author(s):  
T. Bodnár ◽  
A. Sequeira
Keyword(s):  
Blood Coagulation ◽  
Computational Study ◽  
Time Integration ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Clot Formation ◽  
Diffusion Reaction ◽  
Numerical Code ◽  
Injured Region ◽  
Reaction Equations

The process of platelet activation and blood coagulation is quite complex and not yet completely understood. Recently, a phenomenological meaningful model of blood coagulation and clot formation in flowing blood that extends existing models to integrate biochemical, physiological and rheological factors, has been developed. The aim of this paper is to present results from a computational study of a simplified version of this coupled fluid-biochemistry model. A generalized Newtonian model with shear-thinning viscosity has been adopted to describe the flow of blood. To simulate the biochemical changes and transport of various enzymes, proteins and platelets involved in the coagulation process, a set of coupled advection–diffusion–reaction equations is used. Three-dimensional numerical simulations are carried out for the whole model in a straight vessel with circular cross-section, using a finite volume semi-discretization in space, on structured grids, and a multistage scheme for time integration. Clot formation and growth are investigated in the vicinity of an injured region of the vessel wall. These are preliminary results aimed at showing the validation of the model and of the numerical code.

Tied to the Common Core

2016 ◽  
Vol 52 (5) ◽  
pp. 793-840 ◽  
Author(s):  
Yi-Hwa Liou
Keyword(s):  
Common Core ◽  
Educational Leaders ◽  
State Standards ◽  
Leadership Team ◽  
Social Aspect ◽  
Key Factors ◽  
Core State ◽  
Social Network Modeling ◽  
Perception Gap ◽  
The Common

Purpose: Researchers and scholars have called for greater attention to collaboration among and between educational leaders in districtwide reform. This work underlines the important social aspect of such collaboration and further investigates the type of professional interaction among/between district and school leaders particularly around the Common Core State Standards (CCSS) and characterizes such interaction by key factors. Research Method: The work takes place in one school district of more than 30 schools serving students from traditionally marginalized backgrounds. Descriptive statistics, multilevel social network modeling, and network sociograms are used to understand the characteristics of professional interactions around CCSS implementation among district and site leaders. Findings: The findings indicate similarities and differences in characteristics of leaders who likely seek CCSS advice and leaders who likely provide that CCSS advice. Leader self-efficacy in implementing the CCSS positively explains the likelihood of both seeking and providing advice behaviors, and yet other factors (organizational learning, leadership, job satisfaction, and CCSS beliefs) each makes different contributions to the likelihood of seeking and/or providing the CCSS advice. Conclusion and Implications: This work suggests a discrepancy of leaders’ perceptions between advice seekers and providers, signaling a need for closing the perception gap between advice seekers and providers such that the leadership team could better craft coherent norms of collaboration in instructional improvement. Understanding the “why” of CCSS advice ties may help guide leaders toward the “how” to align professional and social aspects of change.

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