Insight into the basis of root growth in Arabidopsis thaliana provided by a simple mathematical model

2006 ◽  
Vol 119 (2) ◽  
pp. 85-93 ◽  
Author(s):  
Akitoshi Iwamoto ◽  
Daisuke Satoh ◽  
Masahiko Furutani ◽  
Shinichiro Maruyama ◽  
Hideaki Ohba ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Simple Mathematical Model ◽  
Insight Into

scholarly journals Mechanosensitive remodeling of the bacterial flagellar motor is independent of direction of rotation

2021 ◽  
Vol 118 (15) ◽  
pp. e2024608118
Author(s):  
Navish Wadhwa ◽  
Yuhai Tu ◽  
Howard C. Berg
Keyword(s):  
Escherichia Coli ◽  
Mathematical Model ◽  
Steady State ◽  
Bacterial Motility ◽  
Flagellar Motor ◽  
Simple Mathematical Model ◽  
Output Torque ◽  
Chemical Stimuli ◽  
Bacterial Flagellar Motor ◽  
Insight Into

Motility is important for the survival and dispersal of many bacteria, and it often plays a role during infections. Regulation of bacterial motility by chemical stimuli is well studied, but recent work has added a new dimension to the problem of motility control. The bidirectional flagellar motor of the bacterium Escherichia coli recruits or releases torque-generating units (stator units) in response to changes in load. Here, we show that this mechanosensitive remodeling of the flagellar motor is independent of direction of rotation. Remodeling rate constants in clockwise rotating motors and in counterclockwise rotating motors, measured previously, fall on the same curve if plotted against torque. Increased torque decreases the off rate of stator units from the motor, thereby increasing the number of active stator units at steady state. A simple mathematical model based on observed dynamics provides quantitative insight into the underlying molecular interactions. The torque-dependent remodeling mechanism represents a robust strategy to quickly regulate output (torque) in response to changes in demand (load).

scholarly journals Global and local contributions to corneal surface curvature: a simple model

2008 ◽  
Vol 67 (1) ◽  
Author(s):  
W. F. Harris
Keyword(s):  
Mathematical Model ◽  
Simple Model ◽  
Tear Film ◽  
Surface Curvature ◽  
Simple Mathematical Model ◽  
Corneal Surface ◽  
Local Effects ◽  
Numerical Example ◽  
Global And Local ◽  
Insight Into

Variations in corneal surface powers reflect variations in the geometry of the cornea.  In particular one can regard corneal surface curvature as a combination of local and global effects.  A simple mathematical model of the cornea is presented which makes use of measurements of the curvature of the anterior and posterior surfaces to decompose the curvature into global and local contributions.  The model gives insight into the source of variations in keratometric measurements, lids and eye turn, perhaps, for global effects and the tear film, perhaps, for local effects.  The model also takes account of the thickness of the cornea.  A numerical example is presented.

scholarly journals Variability of the mechanical properties of bone, and its evolutionary consequences

2006 ◽  
Vol 4 (12) ◽  
pp. 127-135 ◽  
Author(s):  
John D Currey ◽  
Jonathan W Pitchford ◽  
Paul D Baxter
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Mineral Content ◽  
Optimal Allocation ◽  
Compact Bone ◽  
Simple Mathematical Model ◽  
Trade Off ◽  
Evolutionary Consequences ◽  
Insight Into ◽  
Mechanical Phenomena

The relative variabilities (coefficient of variation (CV)) of 10 different mechanical properties of compact bone were determined from 2166 measurements. All measures of variability were made on a minimum of four specimens from any bone. Three pre-yield properties had a CV of about 12%. Six post-yield properties had CVs varying from 24 to 46%. Pre-yield properties increase as a function of mineral content, whereas post-yield properties decrease. These differences give insight into mechanical phenomena occurring at different stages during loading. Furthermore, the fact that some properties are more tightly determined than others has implications for the optimum values set by natural selection. This assertion is made more rigorous using a simple mathematical model for the evolutionarily optimal allocation in a trade-off where one property is imprecisely determined. It is argued that in general the optimum will be biased in favour of the more tightly determined properties than would be the case if all properties had the same CV.

Effect of mobility conditions on the throughput of the Wireless Body Area Network

2020 ◽  
Vol 10 ◽  
Author(s):  
Shilpa Shinde ◽  
Santosh Sonavane
Keyword(s):  
Mathematical Model ◽  
Wireless Body Area Network ◽  
Data Rate ◽  
Hand Movements ◽  
Body Area Network ◽  
Area Network ◽  
Mobility Patterns ◽  
Body Area ◽  
Insight Into ◽  
Leg Movements

Background and objective: In the Wireless Body Area Network (WBAN) sensors are placed on the human body; which has various mobility patterns like seating, walking, standing and running. This mobility typically assisted with hand and leg movements on which most of the sensors are mounted. Previous studies were largely focused on simulations of WBAN mobility without focusing much on hand and leg movements. Thus for realistic studies on performance of the WBAN, it is important to consider hand and leg movements. Thus, an objective of this paper is to investigate an effect of the mobility patterns with hand movements on the throughput of the WBAN. Method: The IEEE 802.15.6 requirements are considered for WBAN design. The WBAN with star topology is used to connect three sensors and a hub. Three types of mobility viz. standing, walking and running with backward and forward hand movements is designed for simulation purpose. The throughput analysis is carried out with the three sets of simulations with standing, walking and running conditions with the speed of 0 m/s, 0.5 m/s and 3 m/s respectively. The data rate was increased from 250 Kb to 10000 Kb with AODV protocol. It is intended to investigate the effect of the hand movements and the mobility conditions on the throughput. Simulation results are analyzed with the aid of descriptive statistics. A comparative analysis between the simulated model and a mathematical model is also introduced to get more insight into the data. Results: Simulation studies showed that as the data rate is increased, throughput is also increased for all mobility conditions however, this increasing trend was discontinuous. In the standing (static) position, the throughput is found to be higher than mobility (dynamic) condition. It is found that, the throughput is better in the running condition than the walking condition. Average values of the throughput in case of the standing condition were more than that of the dynamic conditions. To validate these results, a mathematical model is created. In the mathematical model, a same trend is observed. Conclusion: Overall, it is concluded that the throughput is decreased due to mobility of the WBAN. It is understood that mathematical models have given more insight into the simulation data and confirmed the negative effect of the mobility conditions on throughput. In the future, it is proposed to investigate effect of interference on the designed network and compare the results.

scholarly journals Sound Waves Promote Arabidopsis thaliana Root Growth by Regulating Root Phytohormone Content

2021 ◽  
Vol 22 (11) ◽  
pp. 5739
Author(s):  
Joo Yeol Kim ◽  
Hyo-Jun Lee ◽  
Jin A Kim ◽  
Mi-Jeong Jeong
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Root Growth ◽  
Apical Meristem ◽  
Cell Number ◽  
Root Apical Meristem ◽  
Control Group ◽  
Auxin Signaling ◽  
Ethylene Signaling ◽  
Sound Waves

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.

PLC1 and H2O2 Mediated the Allelopathic Effect of Oridonin on Root Growth in Arabidopsis thaliana

2021 ◽  
Author(s):  
Yue Zhang ◽  
Yanhuang An ◽  
Ning Yang ◽  
Wei Wang ◽  
Ruirui Liu ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Allelopathic Effect
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