A Lotka-Volterra equation with cladocerans in multiple species competition

1998 ◽  
Author(s):  
Susan Gilbreath
2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Chaohong Pan ◽  
Hongyong Wang ◽  
Chunhua Ou

<p style='text-indent:20px;'>Competition stems from the fact that resources are limited. When multiple competitive species are involved with spatial diffusion, the dynamics becomes even complex and challenging. In this paper, we investigate the invasive speed to a diffusive three species competition system of Lotka-Volterra type. We first show that multiple species share a common spreading speed when initial data are compactly supported. By transforming the competitive system into a cooperative system, the determinacy of the invasive speed is studied by the upper-lower solution method. In our work, for linearly predicting the invasive speed, we concentrate on finding upper solutions only, and don't care about the existence of lower solutions. Similarly, for nonlinear selection of the spreading speed, we focus only on the construction of lower solutions with fast decay rate. This greatly develops and simplifies the ideas of past references in this topic.</p>


Author(s):  
Gary Genosko

While Deleuze explored the temporalities of alcoholism in American literature in The Logic of Sense, and Jean Clet Martin, among others, has extended this inquiry by further extracting the alcoholic’s lines of flight from the same literature, this chapter breaks the mould by understanding alcohol, distilled and in its pure form of ethanol, as well as its imbibition, as a question of a component that passes through anthropocentric, and across multiple non-anthropocentric assemblages. The exploitation of ethanol fermentation, for example, exists across species. Indeed, as we entertain more overtly human cultural examples, such as ‘wine’ for cats, a recent Japanese pet trend, the metabolic communion of interspecies companionship requires that the material expressivity of the substance is overcoded because the ‘wine’ is not only non-alcoholic but liquid catnip in a ‘wine’ bottle. Indeed, theorization of the pursuit of shared pleasures – using Guattari’s ethological terms, we might say deterritorializing from deterministic biological factors yet also modifying these in some measure as well (Machinic Unconscious) – and engaging multiple species is this chapter’s goal, achievable by plotting the passages of alcohol and its related components across assemblages and their material and socio-cultural expressive trajectories beyond strictly anthropocentric and Western prerogatives.


Author(s):  
Scott Jukes

Abstract This paper proposes some possibilities for thinking with a landscape as a pedagogical concept, inspired by posthuman theory. The idea of thinking with a landscape is enacted in the Australian Alps (AA), concentrating on the contentious environmental dilemma involving introduced horses and their management in this bio-geographical location. The topic of horses is of pedagogical relevance for place-responsive outdoor environmental educators as both a location-specific problem and an example of a troubling issue. The paper has two objectives for employing posthuman thinking. Firstly, it experiments with the alternative methodological possibilities that posthuman theory affords for outdoor environmental education, including new ways of conducting educational research. Secondly, it explores how thinking with a landscape as a pedagogical concept may help open ways of considering the dilemma that horses pose. The pedagogical concept is enacted through some empirical events which sketch human–horse encounters from the AA. These sketches depict some of the pedagogical conversations and discursive pathways that encounters can provoke. Such encounters and conversations are ways of constructing knowledge of the landscape, covering multiple species, perspectives and discursive opportunities. For these reasons, this paper may be of relevance for outdoor environmental educators, those interested in the AA or posthuman theorists.


2021 ◽  
Vol 58 (1) ◽  
pp. 22-41
Author(s):  
Fabian A. Harang ◽  
Marc Lagunas-Merino ◽  
Salvador Ortiz-Latorre

AbstractWe propose a new multifractional stochastic process which allows for self-exciting behavior, similar to what can be seen for example in earthquakes and other self-organizing phenomena. The process can be seen as an extension of a multifractional Brownian motion, where the Hurst function is dependent on the past of the process. We define this by means of a stochastic Volterra equation, and we prove existence and uniqueness of this equation, as well as giving bounds on the p-order moments, for all $p\geq1$. We show convergence of an Euler–Maruyama scheme for the process, and also give the rate of convergence, which is dependent on the self-exciting dynamics of the process. Moreover, we discuss various applications of this process, and give examples of different functions to model self-exciting behavior.


2021 ◽  
Author(s):  
Cecilia Di Bernardi ◽  
Camilla Wikenros ◽  
Eva Hedmark ◽  
Luigi Boitani ◽  
Paolo Ciucci ◽  
...  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Polina Drozdova ◽  
Alena Kizenko ◽  
Alexandra Saranchina ◽  
Anton Gurkov ◽  
Maria Firulyova ◽  
...  

Abstract Background Vision is a crucial sense for the evolutionary success of many animal groups. Here we explore the diversity of visual pigments (opsins) in the transcriptomes of amphipods (Crustacea: Amphipoda) and conclude that it is restricted to middle (MWS) and long wavelength-sensitive (LWS) opsins in the overwhelming majority of examined species. Results We evidenced (i) parallel loss of MWS opsin expression in multiple species (including two independently evolved lineages from the deep and ancient Lake Baikal) and (ii) LWS opsin amplification (up to five transcripts) in both Baikal lineages. The number of LWS opsins negatively correlated with habitat depth in Baikal amphipods. Some LWS opsins in Baikal amphipods contained MWS-like substitutions, suggesting that they might have undergone spectral tuning. Conclusions This repeating two-step evolutionary scenario suggests common triggers, possibly the lack of light during the periods when Baikal was permanently covered with thick ice and its subsequent melting. Overall, this observation demonstrates the possibility of revealing climate history by following the evolutionary changes in protein families.


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