Observations of Bifurcation and Chaos in Plant Physiological Responses to Light

1997 ◽  
Vol 24 (1) ◽  
pp. 91 ◽  
Author(s):  
Sergey Shabala ◽  
Robert Delbourgo ◽  
Ian Newman
Keyword(s):  
Higher Plants ◽  
Physiological Responses ◽  
Period Doubling ◽  
The Other ◽  
Chaotic Oscillations ◽  
Bifurcation And Chaos ◽  
Intact Plants ◽  
Theoretical Predictions ◽  
Successive Period ◽  
Temperature Responses

Although some theoretical predictions have been made, no experimental evidence of chaotic behaviour in plant physiological responses has been reported. Here we present observations of period- doubling and tripling in higher plants. For leaf bioelectric and temperature responses of maize, tomato, and burweed plants to rhythmical light, two different routes to chaos were found experimentally. One was via successive period-doubling and the other via the formation of intermittently chaotic oscillations from a subharmonic synchronisation. Because these effects appeared in intact plants, under conditions close to those found in nature, they may have wide significance, including for plant phylogenesis.

Coexistence of Multiple Attractors and Crisis Route to Chaos in a Novel Chaotic Jerk Circuit

2016 ◽  
Vol 26 (05) ◽  
pp. 1650081 ◽  
Author(s):  
J. Kengne ◽  
Z. T. Njitacke ◽  
A. Nguomkam Negou ◽  
M. Fouodji Tsostop ◽  
H. B. Fotsin
Keyword(s):  
Equilibrium Points ◽  
Three Dimensional ◽  
Period Doubling ◽  
Chaotic Oscillations ◽  
Multiple Attractors ◽  
Coexistence Of Multiple Attractors ◽  
Theoretical Predictions ◽  
Route To Chaos ◽  
Model Equations ◽  
Good Agreement

In this paper, a novel autonomous RC chaotic jerk circuit is introduced and the corresponding dynamics is systematically investigated. The circuit consists of opamps, resistors, capacitors and a pair of semiconductor diodes connected in anti-parallel to synthesize the nonlinear component necessary for chaotic oscillations. The model is described by a continuous time three-dimensional autonomous system with hyperbolic sine nonlinearity, and may be viewed as a linear transformation of model MO15 previously introduced in [Sprott, 2010]. The structure of the equilibrium points and the discrete symmetries of the model equations are discussed. The bifurcation analysis indicates that chaos arises via the usual paths of period-doubling and symmetry restoring crisis. One of the key contributions of this work is the finding of a region in the parameter space in which the proposed (“elegant”) jerk circuit exhibits the unusual and striking feature of multiple attractors (i.e. coexistence of four disconnected periodic and chaotic attractors). Laboratory experimental results are in good agreement with the theoretical predictions.

scholarly journals Determination of the Height of Hard X-Ray Sources in the Solar Atmosphere by Measurement of Photospheric Albedo Photons

1975 ◽  
Vol 68 ◽  
pp. 239-241
Author(s):  
John C. Brown ◽  
H. F. Van Beek
Keyword(s):  
Solar Atmosphere ◽  
The Other ◽  
X Ray ◽  
Theoretical Predictions ◽  
Source Models ◽  
The One

SummaryThe importance and difficulties of determining the height of hard X-ray sources in the solar atmosphere, in order to distinguish source models, have been discussed by Brown and McClymont (1974) and also in this Symposium (Brown, 1975; Datlowe, 1975). Theoretical predictions of this height, h, range between and 105 km above the photosphere for different models (Brown and McClymont, 1974; McClymont and Brown, 1974). Equally diverse values have been inferred from observations of synchronous chromospheric EUV bursts (Kane and Donnelly, 1971) on the one hand and from apparently behind-the-limb events (e.g. Datlowe, 1975) on the other.

Rolling and Recrystallization Textures in High Purity Al Cold Rolled to Very High Rolling Reductions

2005 ◽  
Vol 495-497 ◽  
pp. 603-608 ◽  
Author(s):  
Atsushi Todayama ◽  
Hirosuke Inagaki
Keyword(s):  
Cold Rolling ◽  
High Purity ◽  
Work Hardening ◽  
Dynamic Recovery ◽  
The Other ◽  
Rolling Reduction ◽  
Theoretical Investigations ◽  
Theoretical Predictions ◽  
Cold Rolled ◽  
Very High

On the basis of Taylor-Bishop-Hill’s theory, many previous theoretical investigations have predicted that, at high rolling reductions, most of orientations should rotate along theβfiber from {110}<112> to {123}<634> and finally into the {112}<111> stable end orientations. Although some exceptions exist, experimental observations have shown, on the other hand, that the maximum on the β fiber is located still at about {123}<634> even after 97 % cold rolling. In the present paper, high purity Al containing 50 ppm Cu was cold rolled up to 99.4 % reduction in thickness and examined whether {112}<111> stable end orientation could be achieved experimentally. It was found that, with increasing rolling reduction above 98 %, {110}<112> decreased, while orientations in the range between {123}<634> and {112}<111> increased, suggesting that crystal rotation along the βfiber from {110}<112> toward {123}<634> and {112}<111> in fact took place. At higher rolling reductions, however, further rotation of this peak toward {112}<111> was extremely sluggish, and even at the highest rolling reduction, it could not arrive at {112}<111>. Such discrepancies between theoretical predictions and experimental observations should be ascribed to the development of dislocation substructures, which were formed by concurrent work hardening and dynamic recovery. Since such development of dislocation substructures are not taken into account in Taylor-Bishop-Hill’s theory, it seems that they can not correctly predict the development of rolling textures at very high rolling reductions, i. e. stable end orientations. On annealing specimens rolled above 98 % reduction in thickness, cube textures were very weak, suggesting that cube bands were almost completely rotated into other orientations during cold rolling. {325}<496>, which lay at an intermediate position between {123}<634> and {112}<111> along theβfiber, developed strongly in the recrystallization textures.

ZERO-CROSS INSTANTANEOUS STATE SETTING FOR CONTROL OF A BIFURCATING H-BRIDGE INVERTER

2007 ◽  
Vol 17 (10) ◽  
pp. 3571-3575 ◽  
Author(s):  
SATOSHI AKATSU ◽  
HIROYUKI TORIKAI ◽  
TOSHIMICHI SAITO
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Period Doubling ◽  
Current Mode ◽  
Nonlinear Phenomena ◽  
Unstable Periodic Orbits ◽  
Bifurcation And Chaos ◽  
Zero Crossing ◽  
Modulation Signal ◽  
A Current

This paper studies stabilization of low-period unstable periodic orbits (UPOs) in a simplified model of a current mode H-bridge inverter. The switching of the inverter is controlled by pulse-width modulation signal depending on the sampled inductor current. The inverter can exhibit rich nonlinear phenomena including period doubling bifurcation and chaos. Our control method is realized by instantaneous opening of inductor at a zero-crossing moment of an objective UPO and can stabilize the UPO instantaneously as far as the UPO crosses zero in principle. Typical system operations can be confirmed by numerical experiments.

Photoreceptor coupling in turtle retina

1998 ◽  
Vol 15 (4) ◽  
pp. 755-764 ◽  
Author(s):  
M.L. FIRSOV ◽  
D.G. GREEN
Keyword(s):  
Receptive Field ◽  
Gap Junctions ◽  
Direct Evidence ◽  
Physiological Responses ◽  
The Other ◽  
Morphological Data ◽  
Chelydra Serpentina ◽  
Intracellular Injection ◽  
Coupled Cells ◽  
High Degree

Photoreceptors in the isolated turtle retina of two species of turtle, Chelydra serpentina and Pseudemus scripta elegans, were penetrated with double-barrel electrodes. Physiological responses were recorded through one barrel and Neurobiotin tracer was injected from the other. Intracellular injection of Neurobiotin revealed patterns of tracer-coupled photoreceptors. Both the patterns of tracer coupling and the electrophysiology suggest a high degree of specificity of connections. Rods seem to be coupled only to rods and green and red cones seem to be coupled to cones of the same spectral type. Receptive-field profiles, measured with a thin, sharply focused slit of light, often had well-defined peaks and troughs in sensitivity. We have taken advantage of this observation and used the position of a peak in sensitivity to locate the position on the retina of a coupled cell. In one rod, it was possible to correlate physiological and morphological data and to show that the peaks in the physiological receptive field occurred at positions on the retina where there were dye-coupled cells. This provides direct evidence that gap junctions produce the physiological coupling between rods.

PERIODICALLY FORCED HYDROCARBON OXIDATION REACTION IN A CSTR

1996 ◽  
Vol 06 (12a) ◽  
pp. 2321-2341 ◽  
Author(s):  
H. S. SIDHU ◽  
L. K. FORBES ◽  
B. F. GRAY
Keyword(s):  
Period Doubling ◽  
Operating Conditions ◽  
Hydrocarbon Oxidation ◽  
Periodic Modulation ◽  
Chaotic Oscillations ◽  
Industrial Practice ◽  
Dynamical Characteristics ◽  
Input And Output ◽  
Periodic Behaviour ◽  
Continuously Stirred Tank Reactor

In this paper we examine in detail the effects of forcing the thermokinetic or the chain-thermal model of hydrocarbon oxidation (proposed by B. F. Gray and C. H. Yang) in a Continuously Stirred Tank Reactor (CSTR). Here, the reaction has been subjected to periodic modulation of the input and output flows of chemicals. This investigation has uncovered rich non-linear dynamical characteristics including primary resonances, super and sub-harmonic resonances, quasi-periodic solutions and chaotic oscillations. These regions of chaos are normally interrupted by windows of periodic behaviour. The transitions to chaos were mainly found to be of three types: Feigenbaum period-doubling cascade, Ruelle-Takens-Newhouse approach through quasi-periodicity, and intermittency. The presence of these chaotic solutions was confirmed by computing the Lyapunov exponents. The results presented here are of potential benefit to industrial practice, since they show great increases in product selectivity when appropriate operating conditions are chosen in this forcing strategy.

scholarly journals Control of period-doubling bifurcation and chaos in a discrete nonlinear system by the feedback of states and parameter adjustment

2003 ◽  
Vol 52 (4) ◽  
pp. 790
Author(s):  
Luo Xiao-Shu ◽  
Chen Guan-Rong ◽  
Wang Bing-Hong ◽  
Fang Jin-Qing ◽  
Zou Yan-Li ◽  
...  
Keyword(s):  
Nonlinear System ◽  
Period Doubling ◽  
Period Doubling Bifurcation ◽  
Bifurcation And Chaos ◽  
Parameter Adjustment

Creativity Thinks on the Significances of Geobiology about the Coal Series

2014 ◽  
Vol 1065-1069 ◽  
pp. 114-118
Author(s):  
Shuo Fu Tian ◽  
Chao Jin Lu ◽  
Yuan Wang
Keyword(s):  
Green Algae ◽  
Higher Plants ◽  
The Other ◽  
Coal Bed ◽  
Geologic History ◽  
Blue Green Algae ◽  
Living Things ◽  
Coal Petrology ◽  
The Relationship ◽  
Lower Plants

It is the components, living things evolution processes, development environments, distribution layers and the earliest time for coal series formation that are investigated and studied in detail based on the author’s graduation thesis, the “Geobiology” , the “China coal petrology” and the other’s some references in this paper. And it is considered that mainly two types of the Coal Series might be distinguish in the geologic history in China, respectively consisted of the lower organisms (especially the lower plants, blue-green algae) and higher organisms (especially the higher plants, pteridophyta, gymnosperms, Anthophyta). Meanwhile, the conclusions can be drawn that the development of the organisms is not only controlled by the environments, on the other hand, the environments and their sediments are also affected by the ecologies of the organisms. So the coal bed or coal series can be used as the marks of the environment explanation, perhaps having some Significances of Geobiology. In additional, the relationship with an unconformity or disconformity is discussed here, too.

Inhibition of δ-Aminolevulinic Acid Synthesis by Glyphosate

Weed Science ◽  
1981 ◽  
Vol 29 (5) ◽  
pp. 571-577 ◽  
Author(s):  
Lynn M. Kitchen ◽  
William W. Witt ◽  
Charles E. Rieck
Keyword(s):  
Carbon Dioxide ◽  
Zea Mays ◽  
Aminolevulinic Acid ◽  
Higher Plants ◽  
Acid Synthesis ◽  
The Other ◽  
Porphyrin Ring ◽  
Fresh Weight ◽  
Ring Compounds ◽  
Site Of Action

The effect of glyphosate [N-(phosphonomethyl) glycine] on barley (Hordeum vulgareL.) and corn (Zea maysL.) shoot δ-aminolevulinic acid (ALA) production was examined by monitoring ALA content in the tissue and measuring incorporation of14C precursors into ALA and chlorophylla. Barley shoot ALA content was significantly decreased by 1 mM glyphosate after 9, 11, and 15 h of illumination. ALA production by treated barley shoots was 30 nmoles•g fresh weight-1•h-1at each interval tested, compared with 75 to 120 nmoles•g fresh weight-1•h-1for the control. In corn shoots, ALA content was reduced 32, 45, and 58% by 0.1, 1.0, and 10.0 mM glyphosate, respectively, after 12 h illumination. Incorporation studies with14C-glutamate,14C-α-ketoglutarate, and14C-glycine into ALA showed a 77, 92, and 91% inhibition, respectively, in barley shoots treated with 1 mM glyphosate. Incorporation of14C-ALA into chlorophyllawas not affected by 1 mM glyphosate. Thus, the site of action of glyphosate may involve two enzyme pathways:one controlling the conversion of α-ketoglutarate to ALA, and the other controlling the condensation of glycine with succinyl CoA to form ALA and carbon dioxide. Inhibition of ALA synthesis blocks synthesis of chlorophyll, as well as all other porphyrin ring compounds found in higher plants. Thus, inhibition of ALA synthesis may be an integral component of the herbicidal mode of action of glyphosate.

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