scholarly journals Spatiotemporal Integration in Plant Tropisms

2018 ◽  
Author(s):  
Yasmine Meroz ◽  
Renaud Bastien ◽  
L Mahadevan

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.

2019 ◽  
Vol 16 (154) ◽  
pp. 20190038 ◽  
Author(s):  
Yasmine Meroz ◽  
Renaud Bastien ◽  
L. Mahadevan

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.


2017 ◽  
Vol 34 (4) ◽  
pp. 1-27
Author(s):  
Luke Mathew Peterson

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.


2016 ◽  
Vol 7 (11) ◽  
pp. 6824-6831 ◽  
Author(s):  
Jérémy R. Rouxel ◽  
Vladimir Y. Chernyak ◽  
Shaul Mukamel

A spatially non-local response tensor description of linear chiral signals such as circular dichroism is developed.


Author(s):  
Ory Schnitzer ◽  
Vincenzo Giannini ◽  
Stefan A. Maier ◽  
Richard V. Craster

According to the hydrodynamic Drude model, surface plasmon resonances of metallic nanostructures blueshift owing to the non-local response of the metal’s electron gas. The screening length characterizing the non-local effect is often small relative to the overall dimensions of the metallic structure, which enables us to derive a coarse-grained non-local description using matched asymptotic expansions; a perturbation theory for the blueshifts of arbitrary-shaped nanometallic structures is then developed. The effect of non-locality is not always a perturbation and we present a detailed analysis of the ‘bonding’ modes of a dimer of nearly touching nanowires where the leading-order eigenfrequencies and eigenmode distributions are shown to be a renormalization of those predicted assuming a local metal permittivity.


2014 ◽  
Vol 47 (50) ◽  
pp. 505005
Author(s):  
Tridib Sadhu ◽  
Satya N Majumdar ◽  
David Mukamel
Keyword(s):  

2017 ◽  
Vol 34 (4) ◽  
pp. 1-27
Author(s):  
Luke Mathew Peterson

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.


Author(s):  
Christine Hernández ◽  
Dan M. Healan

This chapter argues that the Late Classic/Epiclassic ceramic style known as Coyotlatelco has roots in the eastern El Bajío of Near West Mexico. Coyotlatelco became a widespread ceramic tradition in Epiclassic Central Mexico. Its chief defining characteristic is its suite of unsupported and tripod-supported vessels decorated with red-painted geometric designs on plain brown or cream slipped pottery. Ceramic data and radiocarbon dating produced from Tulane University’s Ucareo-Zinapecuaro (U-Z) Project (1989-1995) shed additional light on the ongoing debate regarding whether or not the Coyotlatelco style originates with the native population or if it shows evidence of the migration of non-local people into the central highlands of Mexico. The ceramic chronology for the U-Z source area throughout the Late Formative and Classic periods in NE Michoacan begins a discussion about shared decorative modes among red on brown ceramic types that connect Michoacan with societies in both the El Bajio and the Basin of Mexico regions, including Teotihuacan. The conclusions drawn suggest that the Coyotlatelco ceramic style has deep roots in the pottery traditions of the eastern El Bajio and, given the equally long history of various modes of regional and back migration, there seems little need to look beyond Central Mexico for the origins of Coyotlatleco.


2011 ◽  
Vol 51 (11) ◽  
pp. 113010 ◽  
Author(s):  
H.J. Sun ◽  
P.H. Diamond ◽  
Z.B. Shi ◽  
C.Y. Chen ◽  
L.H. Yao ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document