scholarly journals Spatio-temporal integration in plant tropisms

2019 ◽  
Vol 16 (154) ◽  
pp. 20190038 ◽  
Author(s):  
Yasmine Meroz ◽  
Renaud Bastien ◽  
L. Mahadevan
Keyword(s):  
Response Function ◽  
Shoot Growth ◽  
Analytic Solution ◽  
Temporal Integration ◽  
Time Varying ◽  
Local Response ◽  
History Of ◽  
Non Local ◽  
Spatio Temporal ◽  
Plant Shoots

Tropisms, growth-driven responses to environmental stimuli, cause plant organs to respond in space and time and reorient themselves. Classical experiments from nearly a century ago reveal that plant shoots respond to the integrated history of light and gravity stimuli rather than just responding instantaneously. We introduce a temporally non-local response function for the dynamics of shoot growth formulated as an integro-differential equation whose solution allows us to qualitatively reproduce experimental observations associated with intermittent and unsteady stimuli. Furthermore, an analytic solution for the case of a pulse stimulus expresses the response function as a function of experimentally tractable variables, which we calculate for the case of the phototropic response of Arabidopsis hypocotyls. All together, our model enables us to predict tropic responses to time-varying stimuli, manifested in temporal integration phenomena, and sets the stage for the incorporation of additional effects such as multiple stimuli, gravitational sagging, etc.

scholarly journals Spatiotemporal Integration in Plant Tropisms

2018 ◽  
Author(s):  
Yasmine Meroz ◽  
Renaud Bastien ◽  
L Mahadevan
Keyword(s):  
Response Function ◽  
Shoot Growth ◽  
Analytic Solution ◽  
Light Stimulus ◽  
Temporal Integration ◽  
Local Response ◽  
History Of ◽  
Non Local ◽  
Plant Shoots ◽  
Spatiotemporal Integration

Tropisms, growth-driven responses to environmental stimuli, cause plant organs to respond in space and time and reorient themselves. Classical experiments from nearly a century ago reveal that plant shoots respond to the integrated history of light and gravity stimuli rather than just responding instantaneously. We introduce a temporally non-local response function for the dynamics of shoot growth formulated as an integro-differential equation whose solution allows us to qualitatively reproduce experimental observations associated with intermittent and unsteady stimuli. Furthermore, an analytic solution for the case of a pulse light stimulus expresses the response function as function of experimentally tractable variables for the phototropic response of Arabidopsis hypocotyls. All together, our model enables us to predict tropic responses to time-varying stimuli, manifested in temporal integration phenomena, and sets the stage for the incorporation of additional effects such as multiple stimuli, gravitational sagging etc.

scholarly journals Closing the Frontier, Opening Doors

2021 ◽  
Vol 46 (1) ◽  
pp. 38-58
Author(s):  
Tuomas Tammisto
Keyword(s):  
Papua New Guinea ◽  
Oil Palm ◽  
New Guinea ◽  
Resource Extraction ◽  
Local Response ◽  
Community Members ◽  
Spatial Strategy ◽  
Temporal Process ◽  
History Of ◽  
Spatio Temporal

In this article I examine a recent communal cocoa planting project in a Wide Bay Mengen community in East Pomio, Papua New Guinea in relation to histories of resource extraction. I discuss how the community members modeled the current planting of cocoa in accordance with earlier forms of agriculture, namely copra production and swidden horticulture. The cocoa planting project is linked to a longer history of labour and resource extraction in Pomio. I analyze the cycles of labour recruitment, logging, and oil palm expansion through the framework of the frontier, by which I mean a spatio-temporal process through which certain areas are portrayed as having abundant resources, which are made available for extraction. The cocoa planting project was a local response to these conditions and intended to be a source of income based on inalienated labour and local landholding and a spatial strategy of establishing points of access to other places, called 'doors' by the community members. My aim in this article is twofold. First, I argue that the frontier understood as a spatio-temporal process helps us to conceptualize cycles of resource extraction. Second, I show how people living in areas understood as frontiers form their own analyses and responses to the conditions under which their land, labour, and resources are made available to others. Keywords: cocoa, commodification, frontier, infrastructure, natural resources, oil palm, Papua New Guinea, place, territorialization

Palestine-Israel and the Neoliberal Ideal

2017 ◽  
Vol 34 (4) ◽  
pp. 1-27
Author(s):  
Luke Mathew Peterson
Keyword(s):  
World War I ◽  
Political Conflict ◽  
Territorial Dispute ◽  
Early Twenty ◽  
Economic Forces ◽  
Local Actors ◽  
History Of ◽  
Non Local ◽  
Clash Of Cultures ◽  
Social Upheaval

The following study envisions the modern history of the Palestinian- Israeli conflict through the application of previously underutilized theoretical frames. Beginning with the unprecedented political and social upheaval wrought upon the Middle East after the end of World War I, the article unfolds in three distinct sections. The first section provides an historical introduction to the global, transnational forces that guided the developing infrastructure of political conflict within the region. The second section articulates the ideological parameters of the international political and economic forces (“neoliberalism”) that connect the past and present of political conflict in the region as well as the local (state and non-state) and non-local actors involved in its contemporary manifestation. The third and final section reconceptualizes the Palestinian-Israeli conflict not exclusively as a territorial dispute or as a nebulous clash of cultures, but rather as a deliberate, operational casualty enduring in the service of an aggressive, transnational, and indeed historical force whose trajectory spans the length of the twentieth and early twenty-first centuries: neoliberalism. In each sphere in which the neoliberal ideal has been applied – one, an historical fait accompli, another, a contemporary situation en cours – an important, connective element persists: the distinctly non-local origin of both the historical forces and the contemporary economic manifestations under examination.

scholarly journals A New Approach for Approximate Solution of ADE: Physical-Based Modeling of Carriers in Doping Region

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 458
Author(s):  
Leobardo Hernandez-Gonzalez ◽  
Jazmin Ramirez-Hernandez ◽  
Oswaldo Ulises Juarez-Sandoval ◽  
Miguel Angel Olivares-Robles ◽  
Ramon Blanco Sanchez ◽  
...  
Keyword(s):  
Differential Equation ◽  
Approximate Solution ◽  
Analytic Solution ◽  
Order Differential Equation ◽  
Electric Circuit ◽  
New Approach ◽  
In Doping ◽  
Electric Behavior ◽  
Spatio Temporal ◽  
Physical Phenomena

The electric behavior in semiconductor devices is the result of the electric carriers’ injection and evacuation in the low doping region, N-. The carrier’s dynamic is determined by the ambipolar diffusion equation (ADE), which involves the main physical phenomena in the low doping region. The ADE does not have a direct analytic solution since it is a spatio-temporal second-order differential equation. The numerical solution is the most used, but is inadequate to be integrated into commercial electric circuit simulators. In this paper, an empiric approximation is proposed as the solution of the ADE. The proposed solution was validated using the final equations that were implemented in a simulator; the results were compared with the experimental results in each phase, obtaining a similarity in the current waveforms. Finally, an advantage of the proposed methodology is that the final expressions obtained can be easily implemented in commercial simulators.

scholarly journals Complex partial synchronization patterns in networks of delay-coupled neurons

2019 ◽  
Vol 377 (2153) ◽  
pp. 20180128 ◽  
Author(s):  
D. Nikitin ◽  
I. Omelchenko ◽  
A. Zakharova ◽  
M. Avetyan ◽  
A. L. Fradkov ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Temporal Dynamics ◽  
Delay Systems ◽  
Theme Issue ◽  
Partial Synchronization ◽  
Multiplex Network ◽  
Control Scheme ◽  
Non Local ◽  
Spatio Temporal ◽  
Fast Oscillations

We study the spatio-temporal dynamics of a multiplex network of delay-coupled FitzHugh–Nagumo oscillators with non-local and fractal connectivities. Apart from chimera states, a new regime of coexistence of slow and fast oscillations is found. An analytical explanation for the emergence of such coexisting partial synchronization patterns is given. Furthermore, we propose a control scheme for the number of fast and slow neurons in each layer. This article is part of the theme issue ‘Nonlinear dynamics of delay systems’.

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