scholarly journals Interactions Obtained from Basic Mechanistic Principles: Prey Herds and Predators

Mathematics ◽  
2021 ◽  
Vol 9 (20) ◽  
pp. 2555
Author(s):  
Cecilia Berardo ◽  
Iulia Martina Bulai ◽  
Ezio Venturino

We investigate four predator–prey Rosenzweig–MacArthur models in which the prey exhibit herd behaviour and only the individuals on the edge of the herd are subjected to the predators’ attacks. The key concept is the herding index, i.e., the parameter defining the characteristic shape of the herd. We derive the population equations from the individual state transitions using the mechanistic approach and time scale separation method. We consider one predator and one prey species, linear and hyperbolic responses and the occurrence of predators’ intraspecific competition. For all models, we study the equilibria and their stability and we give the bifurcation analysis. We use standard numerical methods and the software Xppaut to obtain the one-parameter and two-parameter bifurcation diagrams.

2020 ◽  
Author(s):  
Andréanne Beardsell ◽  
Dominique Gravel ◽  
Dominique Berteaux ◽  
Gilles Gauthier ◽  
Jeanne Clermont ◽  
...  

AbstractThe functional response is central to our understanding of any predator–prey system as it establishes the link between trophic levels. Most functional responses are evaluated using phenomenological models linking predator acquisition rate and prey density. However, our ability to measure functional responses using such an approach is often limited in natural systems and the use of inaccurate functions can profoundly affect the outcomes of population and community models. Here, we develop a mechanistic model based on extensive data to assess the functional response of a generalist predator, the arctic fox (Vulpes lagopus), to various tundra prey species (lemmings and the nests of geese, passerines and sandpipers). We found that predator acquisition rates derived from the mechanistic model were consistent with field observations. Although sigmoidal functional responses were previously used to model fox-prey population dynamics, none of our simulations resulted in a saturating response in all prey species. Our results highlight the importance of predator searching components in predator-prey interactions, especially predator speed, while predator acquisition rates were not limited by handling processes. By combining theory with field observations, our study provides evidences that predator acquisition rate is not systematically limited at the highest prey densities observed in a natural system. We reinforce the idea that functional response categories, typically types I, II, and III, should be considered as particular cases along a continuum. Specific functions derived with a mechanistic approach for a range of densities observed in natural communities should improve our ability to model and understand predator-prey systems.


Author(s):  
Alexander Khutoretskii ◽  
Vladimir Nefedkin

In this study, we propose to model the operation of a service concession arrangement in the economic area of municipal heat supply utilities. We offer a scheme of interaction between the concedent and concessionaire in this concessionary arrangement. Currently, the existing regulations regarding the temperature of coolant focusses on the daily average outdoor temperature, and the determination of a “normative” demand for heat energy. On any day of the heating period, this demand is a random variable, whose distribution can be described through the distribution of daily average air temperature. In our model, heat energy is paid for at a fixed price, and the concessionaire pays a penalty for each unit of unsatisfied normative demand. The price and penalty values are the concession parameters, and are determined by the concedent. The concedent’s goal is to minimise the thermal energy cost; the concessionaire’s purpose is to maximise profit. The interaction is formalised as a two-move game model. First, the concedent determines the price and the value of the penalty. Then the concessionaire selects the capacity to be created. The concession’s parameters should be set so that the individual rationality and incentive compatibility conditions are met. Our results prove the existence of Stackelberg equilibrium, and we derive the relevant formulas for computing its parameters. In equilibrium, the optimum capacity for the concessionaire provides a sufficient probability of meeting demand. The price of thermal energy is minimal under this condition. We also formulate a one-parameter model (thermal energy price as a parameter), which is based on a typical concession scheme. In the two-parameter model, the equilibrium capacity and price do not exceed the corresponding parameters of the one-parameter model. The main advantage of the two-parameter model is an “embedded” economic mechanism that prevents the concessionaire’s opportunistic behaviour. By contrast, in the one-parameter model there is no such mechanism. The proposed approach can be applied to a concession for the production of any good or service, provided the concerned parties are interested in the availability and reliability of meeting a corresponding need, which may be described as a random variable. However, typical concession schemes do not penalise unsatisfied demand, so the implementation of our two-parametric model is possible only after modification of the pertinent concession legislation.


2001 ◽  
Vol 32 (3) ◽  
pp. 133-141 ◽  
Author(s):  
Gerrit Antonides ◽  
Sophia R. Wunderink

Summary: Different shapes of individual subjective discount functions were compared using real measures of willingness to accept future monetary outcomes in an experiment. The two-parameter hyperbolic discount function described the data better than three alternative one-parameter discount functions. However, the hyperbolic discount functions did not explain the common difference effect better than the classical discount function. Discount functions were also estimated from survey data of Dutch households who reported their willingness to postpone positive and negative amounts. Future positive amounts were discounted more than future negative amounts and smaller amounts were discounted more than larger amounts. Furthermore, younger people discounted more than older people. Finally, discount functions were used in explaining consumers' willingness to pay for an energy-saving durable good. In this case, the two-parameter discount model could not be estimated and the one-parameter models did not differ significantly in explaining the data.


Author(s):  
Andri Setyorini ◽  
Niken Setyaningrum

Background: Elderly is the final stage of the human life cycle, that is part of the inevitable life process and will be experienced by every individual. At this stage the individual undergoes many changes both physically and mentally, especially setbacks in various functions and abilities he once had. Preliminary study in Social House Tresna Wreda Yogyakarta Budhi Luhur Units there are 16 elderly who experience physical immobilization. In the social house has done various activities for the elderly are still active, but the elderly who experienced muscle weakness is not able to follow the exercise, so it needs to do ROM (Range Of Motion) exercise.   Objective: The general purpose of this research is to know the effect of Range Of Motion (ROM) Active Assitif training to increase the range of motion of joints in elderly who experience physical immobility at Social House of Tresna Werdha Yogyakarta unit Budhi Luhur.   Methode: This study was included in the type of pre-experiment, using the One Group Pretest Posttest design in which the range of motion of the joints before (pretest) and posttest (ROM) was performed  ROM. Subjects in this study were all elderly with impaired physical mobility in Social House Tresna Wreda Yogyakarta Unit Budhi Luhur a number of 14 elderly people. Data analysis in this research use paired sample t-test statistic  Result: The result of this research shows that there is influence of ROM (Range of Motion) Active training to increase of range of motion of joints in elderly who experience physical immobility at Social House Tresna Wredha Yogyakarta Unit Budhi Luhur.  Conclusion: There is influence of ROM (Range of Motion) Active training to increase of range of motion of joints in elderly who experience physical immobility at Social House Tresna Wredha Yogyakarta Unit Budhi Luhur.


2020 ◽  
Vol 22 (11) ◽  
pp. 11-15
Author(s):  
Gan N.Yu. ◽  
Ponomareva L.I. ◽  
Obukhova K.A.

Today, worldview, spiritual and moral problems that have always been reflected in education and upbringing come to the fore in society. In this situation, there is a demand for philosophical categories. One of the priority goals of education in modern conditions is the formation of a reasonable, reflexive person who is able to analyze their actions and the actions of other people. Modern science is characterized by an understanding of the absolute value and significance of childhood in the development of the individual, which implies the need for its multilateral study. In the conditions of democratization of all spheres of life, the child ceases to be a passive object of education and training, and becomes an active carrier of their own meanings of being and the subject of world creation. One of the realities of childhood is philosophizing, so it is extremely timely to address the identification of its place and role in the world of childhood. Children's philosophizing is extremely poorly studied, although the need for its analysis is becoming more obvious. Children's philosophizing is one of the forms of philosophical reflection, which has its own qualitative specificity, on the one hand, and commonality with all other forms of philosophizing, on the other. The social relevance of the proposed research lies in the fact that children's philosophizing can be considered as an intellectual indicator of a child's socialization, since the process of reflection involves the adoption and development of culture. Modern society, in contrast to the traditional one, is ready to "accept" a philosophizing child, which means that it is necessary to determine the main characteristics and conditions of children's philosophizing.


2020 ◽  
Vol 10 (3) ◽  
pp. 43-57
Author(s):  
See Seng Tan

Abstract: The longstanding effort to develop a people-based regionalism in Southeast Asia has been shaped by an inherent tension between the liberal inclination to privilege the individual and the community under formation, on the one hand, and the realist insistence on the primacy of the state, on the other. This article explores the conditions and constraints affecting ASEAN’s progress in remaking Southeast Asia into a people-focused and caring community in three areas: disaster management, development, and democratization (understood here as human rights). Arguably, the persistent gap in Southeast Asia between aspiration and expectation is determined less by political ideology than by the pragmatic responses of ASEAN member states to the forces of nationalism and protectionism, as well as their respective sense of local and regional responsibility.Resumen: El esfuerzo histórico para desarrollar un regionalismo basado en las personas del sudeste de Asia ha estado marcado por una tensión fundamental entre la inclinación liberal de privilegiar el individuo y la comunidad y la insistencia realista sobre la primacía del estado. Este artículo explora las condiciones y limitaciones que afectan el progreso de la ASEAN en la reestructuración de Asia sudoriental en una comunidad centrada en el cuidado de las personas en: gestión de desastres, desarrollo y democratización (i.e., derechos humanos). La brecha persistente en el sudeste asiático entre la aspiración y la expectativa está determinada por las respuestas pragmáticas de los miembros de la ASEAN sometidos a las fuerzas del nacionalismo y proteccionismo, así como su respectivo sentido de responsabilidad local y regional.Résumé: L’effort historique pour développer un régionalisme fondé sur les peuples en Asie du Sud-Est a été marqué par une tension fondamentale entre l’inclination libérale qui privilégie, d’une part, l’individu et la communauté et, d’autre part, l’insistance réaliste sur la primauté de l’État. Cet article explore les conditions et les contraintes qui nuisent aux progrès de l’ANASE dans le cadre d’une refonte de l’Asie du Sud-Est en une communauté centrée et attentive aux peuples dans trois domaines : la gestion des désastres, le développement et la démocratisation (en référence aux droits humains). Le fossé persistant en Asie du Sud-Est entre les aspirations et les attentes est vraisemblablement moins déterminé par l’idéologie politique que par les réponses pragmatiques des États membres de l’ANASE soumis aux forces du nationalisme et du protectionnisme ainsi que par leur sens respectif de la responsabilité locale et régionale.


2010 ◽  
Vol 27 (3) ◽  
pp. 1-23 ◽  
Author(s):  
Marie-Luisa Frick

Against the background of the trend of Islamizing human rights on the one hand, as well as increasing skepticism about the compatibility of Islam and human rights on the other, I intend to analyze the potential of Islamic ethics to meet the requirements for vitalizing the idea of human rights. I will argue that the compatibility of Islam and human rights cannot be determined merely on the basis of comparing the specific content of the Islamic moral code(s) with the rights stipulated in the International Bill of Rights, but by scanning (different conceptions of) Islamic ethics for the two indispensable formal prerequisites of any human rights conception: the principle of universalism (i.e., normative equality) and individualism (i.e., the individual enjoyment of rights). In contrast to many contemporary (political) attempts to reconcile Islam and human rights due to urgent (global) societal needs, this contribution is solely committed to philosophical reasoning. Its guiding questions are “What are the conditions for deriving both universalism and individualism from Islamic ethics?” and “What axiological axioms have to be faded out or reorganized hierarchically in return?”


1984 ◽  
Vol 49 (4) ◽  
pp. 805-820
Author(s):  
Ján Klas

The accuracy of the least squares method in the isotope dilution analysis is studied using two models, viz a model of a two-parameter straight line and a model of a one-parameter straight line.The equations for the direct and the inverse isotope dilution methods are transformed into linear coordinates, and the intercept and slope of the two-parameter straight line and the slope of the one-parameter straight line are evaluated and treated.


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