scholarly journals Serial disparity in the carnivoran backbone unveils a complex adaptive role in metameric evolution

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Borja Figueirido ◽  
Alberto Martín-Serra ◽  
Alejandro Pérez-Ramos ◽  
David Velasco ◽  
Francisco J. Pastor ◽  
...  
Keyword(s):  
Evolutionary Constraint ◽  
Phenotypic Evolution ◽  
Quantitative Studies ◽  
Thoracolumbar Region ◽  
Complex Adaptive ◽  
Dimensional Shape ◽  
A Chain ◽  
Low Dimensional ◽  
Adaptive Role ◽  
Shape Changes

AbstractOrganisms comprise multiple interacting parts, but few quantitative studies have analysed multi-element systems, limiting understanding of phenotypic evolution. We investigate how disparity of vertebral morphology varies along the axial column of mammalian carnivores — a chain of 27 subunits — and the extent to which morphological variation have been structured by evolutionary constraints and locomotory adaptation. We find that lumbars and posterior thoracics exhibit high individual disparity but low serial differentiation. They are pervasively recruited into locomotory functions and exhibit relaxed evolutionary constraint. More anterior vertebrae also show signals of locomotory adaptation, but nevertheless have low individual disparity and constrained patterns of evolution, characterised by low-dimensional shape changes. Our findings demonstrate the importance of the thoracolumbar region as an innovation enabling evolutionary versatility of mammalian locomotion. Moreover, they underscore the complexity of phenotypic macroevolution of multi-element systems and that the strength of ecomorphological signal does not have a predictable influence on macroevolutionary outcomes.

Reconfigurable Acoustic Arrays With Deployable Structure Based on a Hoberman–Miura System Synthesis

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Ningxiner Zhao ◽  
Ryan L. Harne
Keyword(s):  
Acoustic Waves ◽  
Shape Change ◽  
Near Field ◽  
Ring Structure ◽  
Wave Focusing ◽  
System Synthesis ◽  
Reconfigurable Mechanisms ◽  
Acoustic Arrays ◽  
Dimensional Shape ◽  
Low Dimensional

Abstract Curved surfaces are often used to radiate and focus acoustic waves. Yet, when tessellated into reconfigurable surfaces for sake of deployability needs, origami-inspired acoustic arrays may be challenging to hold into curved shape and may not retain flat foldability. On the other hand, deployable mechanisms such as the Hoberman ring are as low-dimensional as many origami tessellations and may maintain curved shape with ease due to ideal rigid bar compositions. This research explores an interface between a Hoberman ring and Miura-ori tessellation that maintain kinematic and geometric compatibility for sake of maintaining curved shapes for sound focusing. The Miura-ori facets are considered to vibrate like baffled pistons and generate acoustic waves that radiate from the ring structure. An analytical model is built to reveal the near field acoustic behavior of acoustic arrays resulting from a Hoberman–Miura system synthesis. Acoustic wave focusing capability is scrutinized and validated through proof-of-principle experiments. Studies reveal wave focusing phenomena distinct to this manifestation of the acoustic array and uncover design and operational influences on wave focusing effectiveness. The results encourage exploration of new interfaces between reconfigurable mechanisms and origami devices where low-dimensional shape change is desired.

scholarly journals Adaptive Shape Kernel-Based Mean Shift Tracker in Robot Vision System

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Chunmei Liu ◽  
Yirui Wang ◽  
Shangce Gao
Keyword(s):  
Manifold Learning ◽  
Vision System ◽  
Mean Shift ◽  
Robot Vision ◽  
Shape Space ◽  
Training Data ◽  
Learning Technique ◽  
Adaptive Kernel ◽  
Dimensional Shape ◽  
Low Dimensional

This paper proposes an adaptive shape kernel-based mean shift tracker using a single static camera for the robot vision system. The question that we address in this paper is how to construct such a kernel shape that is adaptive to the object shape. We perform nonlinear manifold learning technique to obtain the low-dimensional shape space which is trained by training data with the same view as the tracking video. The proposed kernel searches the shape in the low-dimensional shape space obtained by nonlinear manifold learning technique and constructs the adaptive kernel shape in the high-dimensional shape space. It can improve mean shift tracker performance to track object position and object contour and avoid the background clutter. In the experimental part, we take the walking human as example to validate that our method is accurate and robust to track human position and describe human contour.

Regularity of sound change through lexical diffusion: A study of s > h > in Gondi dialects

1998 ◽  
Vol 10 (2) ◽  
pp. 193-220 ◽  
Author(s):  
Bh. Krishnamurti
Keyword(s):  
Diffusion Model ◽  
Central India ◽  
Sound Change ◽  
The West ◽  
Quantitative Studies ◽  
Normal Expectation ◽  
Lexical Diffusion ◽  
A Chain ◽  
Theoretical Proposal ◽  
Dravidian Language

ABSTRACTGondi is a Dravidian language spoken by 2.2 million speakers (Census of India 1981) in the mountains and forests of four adjacent states in central India. Gondi is a chain of several dialects, some of which, at distant points, are perhaps not mutually intelligible. A major dialect division is provided by a two-step sound change: s- > h- in the west, north, and northwest and h- > - in the south and southeast. The present article studies this two-step sound change, which is still in progress, and establishes two facts. First, contrary to the normal expectation that this sound change would be phonetically gradual and lexically abrupt (Neogram-marian type), there is evidence that it has been lexically gradual and perhaps also phonetically gradual (lexical diffusion). Second, phonetic gradualness and regularity in implementation of sound change are properties not incompatible with the mechanism of lexical diffusion. Labov's observation that s > h > has not been reported as a lexically diffused change in many quantitative studies of Portuguese and Spanish (1981) finds a clear exception in Gondi. Under the lexical diffusion model, the regularity of a sound change is defined as the final outcome in a three-stage change of the relevant lexicon: unchanged (u), variant (u ˜ c), and changed (c). If the entire eligible lexicon passed from u to c through u ˜ c, the change would become regular. If all u ˜ c became c and for some reason no item under u became u ˜ c, the sound change would die prematurely, since the variant stage which provided the rule for the innovation would be absent. Since a regular sound change can result from either the Neogrammarian model or the lexical diffusion model, Labov's (1994:542–543) theoretical proposal of complementarity between the kinds of changes resulting from the two mechanisms calls for more studies of sound change in progress to decide the issue.

scholarly journals An effective model for quantification of cell 3Dshape in early embryogenesis

2021 ◽  
Author(s):  
Zelin Li ◽  
Jianfeng Cao ◽  
Zhongying Zhao ◽  
Hong Yan
Keyword(s):  
Cell Fate ◽  
Cell Shape ◽  
Developmental Process ◽  
Morphological Changes ◽  
Shape Space ◽  
Effective Model ◽  
Cell Stage ◽  
Cell Shapes ◽  
Dimensional Shape ◽  
Low Dimensional

Abstract Background: The developmental process is featured by fabulous morphogenesis in multicellular organisms. Describing morphological changes quantitatively concretes the way to investigating both intra and inter cell regulations on cell fate. While Caenorhabditis elegans has been used as a model for cell and development studies for a long time, the exploration of how cell shape is precisely controlled keeps obscured by the lack of methods to model morphological features. Currently, in order to characterize the features of cell shape involved in cell migration and differentiation, there is an increasing demand in analyzing cell shape systematically, especially when many works have contributed to cell reconstruction. Results: In this work, Spherical harmonics and Principal component analysis integrated Cell Shape quantification Models (SPCSMs) is proposed to represent cell shapes in a low-dimensional shape space. SPCSMs incorporates a complete pipeline to quantify cell shapes and analyze their morphological phenotypes in three dimensional (3D) reconstructions. Based on the framework, we extract biological patterns in the lineage of C. elegans embryo before 350-cell stage, during which all hypodermis cells deformed like a funnel and can be recognized by this shape pattern. Finally, SPCSMs is compared with two cell shape representation methods, which substantiates the effectiveness and robustness of our method. Conclusion: SPCSMs provides a general method to decribe shapes in low-dimensional shape space with compact parameters. It can quantify the shapes of cells from single-cell resolution images obtained over one-minute intervals, making it possible for the recognition of developmental patterns in cell lineages. SPCSMs is expected to be an effective model for biologists to explore the relationships between the shapes of cells and their fates.

scholarly journals Integration drives rapid phenotypic evolution in flatfishes

2021 ◽  
Vol 118 (18) ◽  
pp. e2101330118
Author(s):  
Kory M. Evans ◽  
Olivier Larouche ◽  
Sara-Jane Watson ◽  
Stacy Farina ◽  
María Laura Habegger ◽  
...  
Keyword(s):  
Geometric Morphometrics ◽  
Three Dimensional ◽  
Phenotypic Evolution ◽  
Aquatic Habitats ◽  
Skull Shape ◽  
Selective Pressures ◽  
Rapid Process ◽  
Evolutionary Innovation ◽  
Shape Changes ◽  
Trait Space

Evolutionary innovations are scattered throughout the tree of life, and have allowed the organisms that possess them to occupy novel adaptive zones. While the impacts of these innovations are well documented, much less is known about how these innovations arise in the first place. Patterns of covariation among traits across macroevolutionary time can offer insights into the generation of innovation. However, to date, there is no consensus on the role that trait covariation plays in this process. The evolution of cranial asymmetry in flatfishes (Pleuronectiformes) from within Carangaria was a rapid evolutionary innovation that preceded the colonization of benthic aquatic habitats by this clade, and resulted in one of the most bizarre body plans observed among extant vertebrates. Here, we use three-dimensional geometric morphometrics and a phylogenetic comparative toolkit to reconstruct the evolution of skull shape in carangarians, and quantify patterns of integration and modularity across the skull. We find that the evolution of asymmetry in flatfishes was a rapid process, resulting in the colonization of novel trait space, that was aided by strong integration that coordinated shape changes across the skull. Our findings suggest that integration plays a major role in the evolution of innovation by synchronizing responses to selective pressures across the organism.

scholarly journals Quantum computing thanks to Bianchi groups

2019 ◽  
Vol 198 ◽  
pp. 00012 ◽  
Author(s):  
Michel Planat
Keyword(s):  
Quantum Computing ◽  
Trefoil Knot ◽  
Integer Ring ◽  
Universal Quantum ◽  
A Chain ◽  
Low Dimensional ◽  
Free Subgroups ◽  
Knots And Links ◽  
Good Agreement ◽  
Positive Operator Valued Measure

It has been shown that the concept of a magic state (in universal quantum computing: uqc) and that of a minimal informationally complete positive operator valued measure: MIC-POVMs (in quantum measurements) are in good agreement when such a magic state is selected in the set of non-stabilizer eigenstates of permutation gates with the Pauli group acting on it [1]. Further work observed that most found low-dimensional MICs may be built from subgroups of the modular group PS L(2, Z) [2] and that this can be understood from the picture of the trefoil knot and related 3-manifolds [3]. Here one concentrates on Bianchi groups PS L(2, O10) (with O10 the integer ring over the imaginary quadratic field) whose torsion-free subgroups define the appropriate knots and links leading to MICs and the related uqc. One finds a chain of Bianchi congruence n-cusped links playing a significant role [4].

Quantitative studies in ovule development. III. An estimate of shape changes in Phyllostachys aurea

1987 ◽  
Vol 65 (7) ◽  
pp. 1531-1538 ◽  
Author(s):  
Jack Maze ◽  
Rob Scagel ◽  
L. R. Bohm
Keyword(s):  
Principal Components ◽  
Second Law Of Thermodynamics ◽  
Covariance Matrices ◽  
Second Law ◽  
Ovule Development ◽  
Quantitative Studies ◽  
Development Data ◽  
The Relationship ◽  
Shape Changes ◽  
Shape Component

Multivariate analysis of ovule development data from Phyllostachys aurea determined that there are (i) changes in estimators of organization (eigenvectors of principal components axes, determinants of correlation, and variance–covariance matrices); (ii) differences of a shape component in each axis (angles between principal components axes and a vector of isometry); and (iii) an increase in variation in the parameters calculated. Angles between principal components axes are all significantly different from 0° (zero), when calculated from jackknifed estimates, indicating that each axis represents different shape components. Because these vectors are derived from principal components axes, they are another manifestation of correlation structure, i.e., organization. Thus angular differences between vectors are a function of differences in organization. The relationship between organization and vectors implies that the concept of shape is another way of expressing the organization that is inherent in biological systems. The changing organization, including shape, and increasing variation with development are expressions of the increasing complexity concomitant with development. This increasing complexity would be predicted from the theory of Brooks and Wiley as a manifestation of the second law of thermodynamics as expressed in non-equilibrium systems.

scholarly journals Genetic basis and dual adaptive role of floral pigmentation in sunflowers

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Marco Todesco ◽  
Natalia Bercovich ◽  
Amy Kim ◽  
Ivana Imerovski ◽  
Gregory L Owens ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Myb Transcription Factor ◽  
Strongly Correlated ◽  
Pollinator Attraction ◽  
Floral Diversity ◽  
Complex Adaptive ◽  
Genetic And Environmental Factors ◽  
Floral Displays ◽  
Adaptive Role

Variation in floral displays, both between and within species, has been long known to be shaped by the mutualistic interactions that plants establish with their pollinators. However, increasing evidence suggests that abiotic selection pressures influence floral diversity as well. Here, we analyse the genetic and environmental factors that underlie patterns of floral pigmentation in wild sunflowers. While sunflower inflorescences appear invariably yellow to the human eye, they display extreme diversity for patterns of ultraviolet pigmentation, which are visible to most pollinators. We show that this diversity is largely controlled by cis-regulatory variation affecting a single MYB transcription factor, HaMYB111, through accumulation of ultraviolet (UV)-absorbing flavonol glycosides in ligules (the ‘petals’ of sunflower inflorescences). Different patterns of ultraviolet pigments in flowers are strongly correlated with pollinator preferences. Furthermore, variation for floral ultraviolet patterns is associated with environmental variables, especially relative humidity, across populations of wild sunflowers. Ligules with larger ultraviolet patterns, which are found in drier environments, show increased resistance to desiccation, suggesting a role in reducing water loss. The dual role of floral UV patterns in pollinator attraction and abiotic response reveals the complex adaptive balance underlying the evolution of floral traits.

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