scholarly journals Relationship between the Paradox of Enrichment and the Dynamics of Persistence and Extinction in Prey-Predator Systems

Symmetry ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 532
Author(s):  
Jawdat Alebraheem
Keyword(s):  
Numerical Simulations ◽  
Carrying Capacity ◽  
Analytical Techniques ◽  
Type I ◽  
Type Ii ◽  
New Approach ◽  
Predator Prey ◽  
Paradox Of Enrichment ◽  
The One ◽  
Predator System

The paradox of the enrichment phenomenon, considered one of the main counterintuitive observations in ecology, likely destabilizes predator–prey dynamics by increasing the nutrition of the prey. We use two systems to study the occurrence of the paradox of enrichment: The prey–predator system and the one prey, two predators system, with Holling type I and type II functional and numerical responses. We introduce a new approach that involves the connection between the occurrence of the enrichment paradox and persistence and extinction dynamics. We apply two main analytical techniques to study the persistence and extinction dynamics of two and three trophics, respectively. The linearity and nonlinearity of functional and numerical responses plays important roles in the occurrence of the paradox of enrichment. We derive the persistence and extinction conditions through the carrying capacity parameter, and perform some numerical simulations to demonstrate the effects of the paradox of enrichment when increasing carrying capacity.

scholarly journals Dynamic Behaviors of a Nonautonomous Discrete Predator-Prey System Incorporating a Prey Refuge and Holling Type II Functional Response

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Yumin Wu ◽  
Fengde Chen ◽  
Wanlin Chen ◽  
Yuhua Lin
Keyword(s):  
Global Stability ◽  
Numerical Simulations ◽  
Functional Response ◽  
Sufficient Conditions ◽  
Type Ii ◽  
Prey Refuge ◽  
Predator Species ◽  
Predator Prey ◽  
Prey System ◽  
Type Ii Functional Response

A nonautonomous discrete predator-prey system incorporating a prey refuge and Holling type II functional response is studied in this paper. A set of sufficient conditions which guarantee the persistence and global stability of the system are obtained, respectively. Our results show that if refuge is large enough then predator species will be driven to extinction due to the lack of enough food. Two examples together with their numerical simulations show the feasibility of the main results.

Heterogeneity of human luteinizing hormone. Discrimination between acidic and basic preparations

1989 ◽  
Vol 121 (1) ◽  
pp. 73-82 ◽  
Author(s):  
L. A. van Ginkel ◽  
J. G. Loeber
Keyword(s):  
Type I ◽  
Type Ii ◽  
Active Components ◽  
Charge Heterogeneity ◽  
Sialic Acid Content ◽  
Neuraminidase Treatment ◽  
Strong Shift ◽  
Acidic Component ◽  
The One ◽  
Α Subunits

Abstract. The charge heterogeneity of an LH preparation containing relatively acidic components (LH Type I) was studied. Four biological active components, with pI-values of 5.04, 5.60, 6.06 and 6.57 were detected. A total of four different α-subunits, with pI-values of 4.49, 4.79, 5.16 and 6.02 could be detected after incubation at 37°C. With the exception of the most acidic component all these α-subunits were also present in earlier studied LH Type II preparations. After neuraminidase treatment a strong shift to more basic components was observed, resulting in a population of components similar to the one detected in LH Type II preparations. The β-subunits detected were very different from those observed in Type II preparations. All six components detected had pI-values < 7.5. Upon incubation at 56°C these subunits appeared to be unstable resulting in a shift to more basic pI-values, these pI-values being very similar to those of β-subunits observed before in Type II preparations. After neuraminidase treatment, the pH values of the population of β-subunits became identical to those of the population in LH Type II. From these results it is concluded that the major charge difference between LH Type I and Type II is located in the β-subunits. This difference cannot be explained completely by differences in sialic acid content, but may also be due to heat labile charged groups such as sulphate.

DYNAMIC BEHAVIORS OF A KIND OF PREDATOR–PREY SYSTEM WITH IVLEV'S AND BEDDINGTON–DEANGELIS' FUNCTIONAL RESPONSE AND IMPULSIVE RELEASE

2008 ◽  
Vol 08 (04) ◽  
pp. 667-681
Author(s):  
HONGJIAN GUO ◽  
XINYU SONG ◽  
LANSUN CHEN
Keyword(s):  
Periodic Solution ◽  
Numerical Simulations ◽  
Functional Response ◽  
Period Doubling ◽  
Continuous System ◽  
Impulsive System ◽  
Predator Prey ◽  
Impulsive Release ◽  
Predator System ◽  
Bifurcation Chaos

A kind of one-prey two-predator system with Ivlev's and Beddington–DeAngelis' functional response and impulsive release at fixed moments is presented. It is shown that the system has a prey-free periodic solution. By using the Floquet theory and small amplitude perturbation skills, it is proved that the prey-free periodic solution of the system is locally asymptotically stable when the period of impulsive release is less than a critical value. Furthermore, permanence of the system is investigated and the condition of permanence is obtained. Finally, numerical simulations show that the system has complex properties which include periodic solution, period-doubling bifurcation, chaos, chaotic windows, half-period bifurcation. A brief discussion on our results and their relation between the continuous system and the impulsive system are given. The results obtained in this paper are confirmed by numerical simulations.

scholarly journals Scrounging by foragers can resolve the paradox of enrichment

2016 ◽  
Author(s):  
Wataru Toyokawa
Keyword(s):  
Group Living ◽  
Theoretical Models ◽  
Social Foraging ◽  
Predator Population ◽  
Ecological Communities ◽  
Predator Prey ◽  
Paradox Of Enrichment ◽  
Prey System ◽  
The Stability ◽  
Predator System

AbstractTheoretical models of predator-prey system predict that sufficient enrichment of prey can generate large amplitude limit cycles, paradoxically causing a high risk of extinction (the paradox of enrichment). While real ecological communities contain many gregarious species whose foraging behaviour should be influenced by socially transmitted information, few theoretical studies have examined the possibility that social foraging might be a resolution of the paradox. I considered a predator population in which individuals play the producer-scrounger foraging game both in a one-prey-one-predator system and a two-prey-one-predator system. I analysed the stability of a coexisting equilibrium point in the former one-prey system and that of non-equilibrium dynamics of the latter two-prey system. The result showed that social foraging can stabilise both systems and thereby resolves the paradox of enrichment when scrounging behaviour is prevalent in predators. This suggests a previously neglected mechanism underlying a powerful effect of group-living animals on sustainability of ecological communities.

scholarly journals Photoreactive UV-Crosslinkable Acrylic Pressure-Sensitive Adhesives (PSA) Containing Multifunctional Photoinitiators

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4413
Author(s):  
Marcin Bartkowiak ◽  
Zbigniew Czech ◽  
Hyun-Joong Kim ◽  
Gyu-Seong Shim ◽  
Małgorzata Nowak ◽  
...  
Keyword(s):  
Shear Strength ◽  
Ultraviolet Radiation ◽  
Type I ◽  
Type Ii ◽  
Pressure Sensitive Adhesives ◽  
Crosslinking Process ◽  
Pressure Sensitive ◽  
Peel Adhesion ◽  
The One ◽  
Uv Technology

The use of ultraviolet radiation (UV) technology for the crosslinking of acrylic pressure-sensitive adhesives (PSA) is the one of various crosslinking methods, being the alternative to the conventional crosslinking process of solvent-based acrylic systems. It also requires a photoinitiator to absorb the impinging UV and induce photocrosslinking. As previously mentioned, a photoinitiator is one of the important and necessary components in UV-inducted crosslinking of acrylic pressure-sensitive adhesives. The activity of multifunctional conventional saturated photoinitiators of type I and type II, especially benzophenone-based in the photoreactive UV-crosslinkable acrylic PSA was described. The effect of the multifunctional type-II photoinitiators on the acrylic PSA, such as tack, peel adhesion and shear strength were summarized.

COMPLEXITY OF AN IVLEV'S PREDATOR-PREY MODEL WITH PULSE

2007 ◽  
Vol 10 (02) ◽  
pp. 217-231 ◽  
Author(s):  
GUOPING PANG ◽  
LANSUN CHEN
Keyword(s):  
Numerical Simulations ◽  
Functional Response ◽  
Period Doubling ◽  
Impulsive System ◽  
Bifurcation Diagrams ◽  
Bifurcation And Chaos ◽  
Dynamic Complexity ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Predator System

In this paper, we investigate the extinction, permanence and dynamic complexity of the two-prey, one-predator system with Ivlev's functional response and impulsive perturbation on the predator at fixed moments. Conditions for the extinction and permanence of the system are established via the comparison theorem. Numerical simulations are carried out to explain the conclusions we obtain. Furthermore, the resulting bifurcation diagrams clearly show that the impulsive system takes on many forms of complexity including period-doubling bifurcation, period-halving bifurcation, and chaos.

Correction of the Student T Statistic for Nonindependence of Sample Observations

1992 ◽  
Vol 75 (3) ◽  
pp. 1011-1020 ◽  
Author(s):  
Donald W. Zimmerman ◽  
Richard H. Williams ◽  
Bruno D. Zumbo
Keyword(s):  
Unbiased Estimate ◽  
Random Variables ◽  
Type I ◽  
Type Ii ◽  
Population Variance ◽  
Type I Errors ◽  
Computer Simulation Study ◽  
The One ◽  
Type Ii Errors ◽  
Independent Identically Distributed

A computer-simulation study examined the one-sample Student t test under violation of the assumption of independent sample observations. The probability of Type I errors increased, and the probability of Type II errors decreased, spuriously elevating the entire power function. The magnitude of the change depended on the correlation between pairs of sample values as well as the number of sample values that were pairwise correlated. A modified t statistic, derived from an unbiased estimate of the population variance that assumed only exchangeable random variables instead of independent, identically distributed random variables, effectively corrected for nonindependence for all degrees of correlation and restored the probability of Type I and Type II errors to their usual values.

DUALITY, CONFINEMENT AND SUPERSYMMETRY IN RESTRICTED QUANTUM CHROMODYNAMICS (RCD)

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3592-3604
Author(s):  
J. M. S. RANA
Keyword(s):  
Quantum Chromodynamics ◽  
Meissner Effect ◽  
Quantum Corrections ◽  
Type I ◽  
Type Ii ◽  
Current Correlation ◽  
Vortex Solutions ◽  
The One ◽  
The Masses ◽  
Repulsive Forces

Electromagnetic duality has been utilized to study the isocolor charge-dyon interactions in Restricted Quantum Chromodynamics (RCD),in terms of current-current correlation (in magnetic gauge)using dielectric and permeability parameters of the associated vacuum. In the state of dyonic superconductivity, it has been shown that the dual propagators behave as 1/k4 (for small k2), which in analogy with superconductivity (dual superconductivity) leads to the confinement of colored fluxes associated with dyonic quarks vide generalized Meissner effect. Based on semi-quantitative analysis of vortex solutions of RCD and by calculating the masses for the massive collective modes of the condensed vacuum, the expressions for the London penetration depth, coherence length and the associated flux energy functions for the type I and type II superconducting media have been obtained. It has further been demonstrated that in the type I medium, vortices tend to coalesce and hence are attractive, while the energy function supports repulsive forces between vortices in the type II superconducting medium. The RCD has been supersymmetrized in N =1 limit and the supersymmetric dyonic solutions have been obtained. In the dyonic background gauge one-loop quantum corrections to the dyonic mass have been calculated and it has been shown that the one-loop quantum corrections lead no change in classical mass of the dyon.

scholarly journals A semantic typology of location, existence, possession and copular verbs: areal patterns of polysemy in Mainland East and Southeast Asia

Linguistics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hilary Chappell ◽  
Shanshan Lü
Keyword(s):  
Southeast Asia ◽  
The Other ◽  
Type I ◽  
Type Ii ◽  
Type Iii ◽  
Type Iv ◽  
Diachronic Change ◽  
East And Southeast Asia ◽  
The One ◽  
Semantic Typology

Abstract This study is based on a sample of 116 languages from the Mainland East and Southeast Asian linguistic area. Its first objective is to examine four distinct synchronic patterns of areal polysemy, created by the semantic domains of copular, locative, existential and possessive verbs and the constructions they form. As a consequence, its second objective is to model the diachronic change underlying four language types identified on this basis from the data. We argue that there are three grammaticalization pathways which motivate the four synchronic patterns: Type III languages are distinguished by the grammaticalization chain: (Postural verb) > (Dwell) > Locative > Existential > Possessive, while the other two types, Type II and Type IV, show an opposing pathway: (Grasp) > Possessive > Existential. Type I and Type II languages additionally reveal a recurrent polysemy between Locative and Copular verbs. On this basis, an implicational universal is adduced to the effect that no diachronic adjacency exists between locative and possessive constructions. Crucially, the intervening stage of an existential construction provides the necessary bridging context for possessive reanalysis in this first pathway, while possessive verbs are formally distinct from locatives in the second, bearing no diachronic relationship to them. The findings on the patterns of polysemy sharing reinforce the notion of a clear typological split between Tibeto-Burman languages on the one hand, and Sinitic, Kra–Dai, Hmong–Mien, and Austroasiatic on the other.

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