Leaf Shape Diversity: From Genetic Modules to Computational Models

2021 ◽  
Vol 72 (1) ◽  
pp. 325-356
Author(s):  
Neha Bhatia ◽  
Adam Runions ◽  
Miltos Tsiantis
Keyword(s):  
Computational Models ◽  
Leaf Shape ◽  
Three Dimensional ◽  
Carnivorous Plants ◽  
Cellular Growth ◽  
Plant Leaves ◽  
Local Growth ◽  
Relative Growth ◽  
Combined Use ◽  
Key Aspects

Plant leaves display considerable variation in shape. Here, we introduce key aspects of leaf development, focusing on the morphogenetic basis of leaf shape diversity. We discuss the importance of the genetic control of the amount, duration, and direction of cellular growth for the emergence of leaf form. We highlight how the combined use of live imaging and computational frameworks can help conceptualize how regulated cellular growth is translated into different leaf shapes. In particular, we focus on the morphogenetic differences between simple and complex leaves and how carnivorous plants form three-dimensional insect traps. We discuss how evolution has shaped leaf diversity in the case of complex leaves, by tinkering with organ-wide growth and local growth repression, and in carnivorous plants, by modifying the relative growth of the lower and upper sides of the leaf primordium to create insect-digesting traps.

An efficient approach to converting three-dimensional image data into highly accurate computational models

2008 ◽  
Vol 366 (1878) ◽  
pp. 3155-3173 ◽  
Author(s):  
P.G Young ◽  
T.B.H Beresford-West ◽  
S.R.L Coward ◽  
B Notarberardino ◽  
B Walker ◽  
...  
Keyword(s):  
Mesh Generation ◽  
Computational Models ◽  
Three Dimensional ◽  
Image Data ◽  
Model Material ◽  
Imaging Data ◽  
Material Inhomogeneity ◽  
Dimensional Image ◽  
Wide Range ◽  
Impact Modelling

Image-based meshing is opening up exciting new possibilities for the application of computational continuum mechanics methods (finite-element and computational fluid dynamics) to a wide range of biomechanical and biomedical problems that were previously intractable owing to the difficulty in obtaining suitably realistic models. Innovative surface and volume mesh generation techniques have recently been developed, which convert three-dimensional imaging data, as obtained from magnetic resonance imaging, computed tomography, micro-CT and ultrasound, for example, directly into meshes suitable for use in physics-based simulations. These techniques have several key advantages, including the ability to robustly generate meshes for topologies of arbitrary complexity (such as bioscaffolds or composite micro-architectures) and with any number of constituent materials (multi-part modelling), providing meshes in which the geometric accuracy of mesh domains is only dependent on the image accuracy (image-based accuracy) and the ability for certain problems to model material inhomogeneity by assigning the properties based on image signal strength. Commonly used mesh generation techniques will be compared with the proposed enhanced volumetric marching cubes (EVoMaCs) approach and some issues specific to simulations based on three-dimensional image data will be discussed. A number of case studies will be presented to illustrate how these techniques can be used effectively across a wide range of problems from characterization of micro-scaffolds through to head impact modelling.

scholarly journals Towards More Realistic Leaf Shapes in Functional-Structural Plant Models

Symmetry ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 278 ◽  
Author(s):  
Dominik Schmidt ◽  
Katrin Kahlen
Keyword(s):  
Fluctuating Asymmetry ◽  
Leaf Shape ◽  
Three Dimensional ◽  
Directional Asymmetry ◽  
The Novel ◽  
Shape Model ◽  
Plant Model ◽  
Virtual Plant ◽  
Perfect Symmetry

Fluctuating asymmetry in plant leaves is a widely used measure in geometric morphometrics for assessing random deviations from perfect symmetry. In this study, we considered the concept of fluctuating asymmetry to improve the prototype leaf shape of the functional-structural plant model L-Cucumber. The overall objective was to provide a realistic geometric representation of the leaves for the light sensitive plant reactions in the virtual plant model. Based on three-dimensional data from several hundred in situ digitized cucumber leaves comparisons of model leaves and measurements were conducted. Robust Bayesian comparison of groups was used to assess statistical differences between leaf halves while respecting fluctuating asymmetries. Results indicated almost no directional asymmetry in leaves comparing different distances from the prototype while detecting systematic deviations shared by both halves. This information was successfully included in an improved leaf prototype and implemented in the virtual plant model L-Cucumber. Comparative virtual plant simulations revealed a slight improvement in plant internode development against experimental data using the novel leaf shape. Further studies can now focus on analyses of stress on the 3D-deformation of the leaf and the development of a dynamic leaf shape model.

Effects of Ride Motion on the Speed and Accuracy of In-Vehicle Pointing Tasks

2005 ◽  
Vol 49 (12) ◽  
pp. 1119-1123
Author(s):  
Kevin A. Rider ◽  
Bernard J. Martin
Keyword(s):  
Principal Direction ◽  
Three Dimensional ◽  
Movement Speed ◽  
Moving Vehicle ◽  
Combined Use ◽  
Principal Axes ◽  
Vehicle Acceleration ◽  
The Relationship ◽  
Speed And Accuracy

Terrain-induced vibration of a moving vehicle adversely affects the ability to quickly and accurately perform in-vehicle pointing tasks by altering the planned fingertip trajectory. The relationship between movement speed and accuracy is a result of the combined use of visual and somatosensory feedbacks which are used to discern movement deviations and make necessary compensatory movements. Participants (N=20) performed three-dimensional rapid pointing tasks under stationary and ride motion conditions to three touchpanel displays. Ride motion contributed to increased reaction and movement times and increased endpoint variability. Trajectory deviations were correlated to the principal direction of vehicle acceleration. Reaches orthogonal to the dominant vehicle acceleration exhibited larger endpoint variability, and reaches to the elevated touchpanel resulted in the largest variability across all motion conditions. Principal axes of endpoint ellipses were along the on-axis and off-axis directions of fingertip movement.

scholarly journals Positional variation rather than salt stress dominates changes in three-dimensional leaf shape patterns in cucumber canopies

2019 ◽  
Author(s):  
Dominik Schmidt ◽  
Katrin Kahlen
Keyword(s):  
Salt Stress ◽  
Stress Responses ◽  
Leaf Shape ◽  
Three Dimensional ◽  
Size Variation ◽  
Canopy Architecture ◽  
Shape Variation ◽  
Stress Study ◽  
Salinity Levels ◽  
Adaptation Processes

Abstract Leaf shape plays a key role in the interaction of a plant with its environment, best-known in the plant’s light harvest. Effects of the environment on the interplay of canopy architecture and physiological functioning can be estimated using functional-structural plant models (FSPMs). In order to reduce the complexity of canopy simulations, leaf shape models used in FSPMs are often simple prototypes scaled to match current leaf area. L-Cucumber is such an FSPM, whose leaf prototype mimics average real leaf shape of unstressed cucumber plants well. However, adaptation processes or stress responses may lead to non-proportional changes in leaf geometries, which, for example, could affect length to width ratios or curvatures. The current leaf shape model in L-Cucumber is static and hence does not incorporate changes in leaf shape within or between plants. Thus, the aim of this study was to estimate leaf shape variation and exemplarily study its effects on FSPM simulations. Three-dimensional leaf coordinate data from a salt stress study were analysed with a robust Bayesian mixed-effects model for estimating leaf shape depending on rank, size and salinity. Results showed that positional and size variation rather than salinity levels dominated 3D leaf shape patterns of cucumber. Considering variable leaf shapes in relation to this main sources of variation in L-Cucumber simulations, only minor effects compared to a realistic, yet static average shape were found. However, with similar computational demands variation in shapes other studies highly sensitive to shape dynamics, for example, pesticide spraying might be affected more strongly.

scholarly journals Experience of employment of computational models for water quality modelling

2019 ◽  
Vol 97 ◽  
pp. 05030 ◽  
Author(s):  
Anatoly Krutov ◽  
Dilshod Bazarov ◽  
Begzod Norkulov ◽  
Bakhtiyar Obidov ◽  
Bobur Nazarov
Keyword(s):  
Computational Models ◽  
Numerical Models ◽  
Qualitative Difference ◽  
Three Dimensional ◽  
Sufficient Conditions ◽  
Aral Sea ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model ◽  
Wind Currents

The purpose of the article is to develop the required and sufficient conditions under which numerical methods can be used for engineering calculations and for scientific research of hydrodynamic processes in solving practical problems related to predicting the spread of pollutants in water bodies and streams. The conducted studies consisted in comparing the results of laboratory experiments and mathematical modelling, in particular the distribution of heat in a stream with different temperature in water layers was studied. To check the adequacy of the proposed numerical models, calculations were performed and comparisons were made with the results of experimental data. The obtained results allowed to determine the boundaries of the qualitative difference in the flow behaviour for different numbers of Froude and Reynolds. The accuracy of the method was also studied. A number of additional requirements for numerical models were proposed in addition to approcsimation and stability, such as requirements of conservativeness (divergence), existence of trivial solutions on grids, possibility to calculate highly unsteady, quasi-stable, pulsating and stationary flows, requirement of invariance of linearized equations, as well as the requirement of a one-dimensional scheme to be a consequence of a two-dimensional scheme. Distribution of velocities of wind currents using a three-dimensional and two-dimensional model was studied for a real object. A shallow-water bay of the Aral Sea was chosen as the object for the research. Comparison of the calculation results for both models showed that the flow velocity fields, as well as the distribution of pollutants in shallow waters, can be performed using a two-dimensional model.

Fo and Ni Relations in Olivine Differentiate between Crystallization and Diffusion Trends

2020 ◽  
Author(s):  
Boris Gordeychik ◽  
Tatiana Churikova ◽  
Thomas Shea ◽  
Andreas Kronz ◽  
Alexander Simakin ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Computational Models ◽  
Three Dimensional ◽  
Crystal Shape ◽  
Diffusion Anisotropy ◽  
Progressive Loss ◽  
Theoretical And Computational Models ◽  
Diffusion Controlled ◽  
Mafic Magmas ◽  
And Diffusion

Abstract Nickel is a strongly compatible element in olivine, and thus fractional crystallization of olivine typically results in a concave-up trend on a Fo–Ni diagram. ‘Ni-enriched’ olivine compositions are considered those that fall above such a crystallization trend. To explain Ni-enriched olivine crystals, we develop a set of theoretical and computational models to describe how primitive olivine phenocrysts from a parent (high-Mg, high-Ni) basalt re-equilibrate with an evolved (low-Mg, low-Ni) melt through diffusion. These models describe the progressive loss of Fo and Ni in olivine cores during protracted diffusion for various crystal shapes and different relative diffusivities for Ni and Fe–Mg. In the case when the diffusivity of Ni is lower than that for Fe–Mg interdiffusion, then olivine phenocrysts affected by protracted diffusion form a concave-down trend that contrasts with the concave-up crystallization trend. Models for different simple geometries show that the concavity of the diffusion trend does not depend on the size of the crystals and only weakly depends on their shape. We also find that the effect of diffusion anisotropy on trend concavity is of the same magnitude as the effect of crystal shape. Thus, both diffusion anisotropy and crystal shape do not significantly change the concave-down diffusion trend. Three-dimensional numerical diffusion models using a range of more complex, realistic olivine morphologies with anisotropy corroborate this conclusion. Thus, the curvature of the concave-down diffusion trend is mainly determined by the ratio of Ni and Fe–Mg diffusion coefficients. The initial and final points of the diffusion trend are in turn determined by the compositional contrast between mafic and more evolved melts that have mixed to cause disequilibrium between olivine cores and surrounding melt. We present several examples of measurements on olivine from arc basalts from Kamchatka, and published olivine datasets from mafic magmas from non-subduction settings (lamproites and kimberlites) that are consistent with diffusion-controlled Fo–Ni behaviour. In each case the ratio of Ni and Fe–Mg diffusion coefficients is indicated to be <1. These examples show that crystallization and diffusion can be distinguished by concave-up and concave-down trends in Fo–Ni diagrams.

Computational Models for Sandwich Panels and Shells

1996 ◽  
Vol 49 (3) ◽  
pp. 155-199 ◽  
Author(s):  
Ahmed K. Noor ◽  
W. Scott Burton ◽  
Charles W. Bert
Keyword(s):  
Computational Models ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Local Buckling ◽  
Sandwich Panels ◽  
Free Vibrations ◽  
Sandwich Plates ◽  
Material Parameters ◽  
Sandwich Plates And Shells ◽  
Plates And Shells

The focus of this review is on the hierarchy of computational models for sandwich plates and shells, predictor-corrector procedures, and the sensitivity of the sandwich response to variations in the different geometric and material parameters. The literature reviewed is devoted to the following application areas: heat transfer problems; thermal and mechanical stresses (including boundary layer and edge stresses); free vibrations and damping; transient dynamic response; bifurcation buckling, local buckling, face-sheet wrinkling and core crimping; large deflection and postbuckling problems; effects of discontinuities (eg, cutouts and stiffeners), and geometric changes (eg, tapered thickness); damage and failure of sandwich structures; experimental studies; optimization and design studies. Over 800 relevant references are cited in this review, and another 559 references are included in a supplemental bibliography for completeness. Extensive numerical results are presented for thermally stressed sandwich panels with composite face sheets showing the effects of variation in their geometric and material parameters on the accuracy of the free vibration response, and the sensitivity coefficients predicted by eight different modeling approaches (based on two-dimensional theories). The standard of comparison is taken to be the analytic three-dimensional thermoelasticity solutions. Some future directions for research on the modeling of sandwich plates and shells are outlined.

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