scholarly journals Hypoxia shapes coral reefs

2018 ◽  
Author(s):  
David Blakeway
Keyword(s):  
Three Dimensional ◽  
Distribution Data ◽  
Scale Invariant ◽  
Ecological Processes ◽  
Network Cell ◽  
Invariant Structure ◽  
Multi Scale ◽  
Geometric Patterns ◽  
Calm Weather ◽  
The Many

The three-dimensional form of a coral reef emerges from thousands of years of ecological interactions between reef-building organisms and their environment. Time integrates those interactions, such that the predominant ecological processes are distilled into reef form, often as striking geometric patterns. Several of these patterns have a fractal appearance, exhibiting nested, scale-invariant structure. Cellular reefs are one fractal reef morphotype, characterised by the presence of subcircular, bowl-shaped, depressions (‘cells’) within the reef network. Cell diameters range from approximately 10 metres to 1 kilometre, the larger cells being compound structures containing multiple smaller cells. The common attribute shared by cellular reefs of all scales is an abundance of staghorn Acropora. Staghorn’s fast growth, fuelled by a correspondingly fast metabolism, allows them to rapidly fill lagoons, but leaves them vulnerable to reduced water flow as their own growth begins to impede lagoonal circulation. This article outlines a conceptual model of multi-scale cellular reef development, based on water quality and coral distribution data from the cellular reefs of Western Australia’s Houtman Abrolhos Islands. The key process in the model is density-stratification of the water column during extended periods of warm, calm, weather. Warm water in the shallows traps stable pools of cooler and denser water at depth. The trapped water is rapidly depleted of oxygen, which causes extensive mortality among staghorn colonies. This initiates a negative feedback process in which ongoing growth of colonies above the stratification boundary further reduces water circulation at depth, such that subsequent stratification events kill increasingly larger areas of the reef, eventually producing massive, stagnant cells in which few corals can survive. Investigating the many other reef patterns may provide similar insights into the predominant natural ecological processes occurring on those reefs.

scholarly journals Hypoxia shapes coral reefs

2018 ◽  
Author(s):  
David Blakeway
Keyword(s):  
Three Dimensional ◽  
Distribution Data ◽  
Scale Invariant ◽  
Ecological Processes ◽  
Network Cell ◽  
Invariant Structure ◽  
Multi Scale ◽  
Geometric Patterns ◽  
Calm Weather ◽  
The Many

The three-dimensional form of a coral reef emerges from thousands of years of ecological interactions between reef-building organisms and their environment. Time integrates those interactions, such that the predominant ecological processes are distilled into reef form, often as striking geometric patterns. Several of these patterns have a fractal appearance, exhibiting nested, scale-invariant structure. Cellular reefs are one fractal reef morphotype, characterised by the presence of subcircular, bowl-shaped, depressions (‘cells’) within the reef network. Cell diameters range from approximately 10 metres to 1 kilometre, the larger cells being compound structures containing multiple smaller cells. The common attribute shared by cellular reefs of all scales is an abundance of staghorn Acropora. Staghorn’s fast growth, fuelled by a correspondingly fast metabolism, allows them to rapidly fill lagoons, but leaves them vulnerable to reduced water flow as their own growth begins to impede lagoonal circulation. This article outlines a conceptual model of multi-scale cellular reef development, based on water quality and coral distribution data from the cellular reefs of Western Australia’s Houtman Abrolhos Islands. The key process in the model is density-stratification of the water column during extended periods of warm, calm, weather. Warm water in the shallows traps stable pools of cooler and denser water at depth. The trapped water is rapidly depleted of oxygen, which causes extensive mortality among staghorn colonies. This initiates a negative feedback process in which ongoing growth of colonies above the stratification boundary further reduces water circulation at depth, such that subsequent stratification events kill increasingly larger areas of the reef, eventually producing massive, stagnant cells in which few corals can survive. Investigating the many other reef patterns may provide similar insights into the predominant natural ecological processes occurring on those reefs.

scholarly journals Performance evaluation of SIFT against common image deformations on iban plaited mat motif images

2021 ◽  
Vol 23 (3) ◽  
pp. 1470
Author(s):  
Silvia Joseph ◽  
Irwandi Hipiny ◽  
Hamimah Ujir ◽  
Sarah Flora Samson Juan ◽  
Jacey-Lynn Minoi
Keyword(s):  
Threshold Value ◽  
Scale Invariant ◽  
Traditional Beliefs ◽  
Geometric Patterns ◽  
Multiple Threshold ◽  
Sift Features ◽  
The Many ◽  
Rotation Set ◽  
Scale Invariant Feature ◽  
Special Meaning

Decorative plaited mat is one of the many examples of rich plait work often seen on Borneo handicraft products. The plaited mats are decorated with simple and complex motif designs; each has its own special meaning and taboos. The motif designs are used as a reflection of environment and the traditional beliefs in the Iban community. In line with efforts from UNESCO’s and Sarawak Government’s, digitization, and the use of IR4.0 technologies to preserve and promote this cultural heritage is encouraged. Towards this end goal, we present a novel image dataset containing 10 Iban plaited mat motif classes. The plaited mat motifs are made of diagonal and symmetrical shapes, as well as geometric and non-geometric patterns. Classification’s accuracy using scale-invariant feature transform (SIFT) features was evaluated against 6 common image deformations: zoom+rotation, viewpoint, image blur, JPEG compression, scale and illumination, across multiple threshold values. Varying degrees of each deformation were applied to a digitally cleaned (and cropped) image of each mat motif class. We used RANSAC to remove outliers from the noisy SIFT matching result. The optimal threshold value is 2.0e-2 with a reported 100.0% matching accuracy for the scale change and zoom+rotation set.

Three-dimensional Reconstruction of Microscopic Image Based on Multi-ST Algorithm

2020 ◽  
Vol 64 (2) ◽  
pp. 20506-1-20506-7
Author(s):  
Min Zhu ◽  
Rongfu Zhang ◽  
Pei Ma ◽  
Xuedian Zhang ◽  
Qi Guo
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Scale Model ◽  
Microscopic Image ◽  
Multi Scale ◽  
Gaussian Pyramid ◽  
Cost Aggregation ◽  
Dimensional Reconstruction ◽  
Image Pairs ◽  
Accurate Matching

Abstract Three-dimensional (3D) reconstruction is extensively used in microscopic applications. Reducing excessive error points and achieving accurate matching of weak texture regions have been the classical challenges for 3D microscopic vision. A Multi-ST algorithm was proposed to improve matching accuracy. The process is performed in two main stages: scaled microscopic images and regularized cost aggregation. First, microscopic image pairs with different scales were extracted according to the Gaussian pyramid criterion. Second, a novel cost aggregation approach based on the regularized multi-scale model was implemented into all scales to obtain the final cost. To evaluate the performances of the proposed Multi-ST algorithm and compare different algorithms, seven groups of images from the Middlebury dataset and four groups of experimental images obtained by a binocular microscopic system were analyzed. Disparity maps and reconstruction maps generated by the proposed approach contained more information and fewer outliers or artifacts. Furthermore, 3D reconstruction of the plug gauges using the Multi-ST algorithm showed that the error was less than 0.025 mm.

scholarly journals Three-Dimensional Thematic Map Imaging of the Yacht Port on the Example of the Polish National Sailing Centre Marina in Gdańsk

2021 ◽  
Vol 11 (15) ◽  
pp. 7016
Author(s):  
Pawel S. Dabrowski ◽  
Cezary Specht ◽  
Mariusz Specht ◽  
Artur Makar
Keyword(s):  
Spatial Data ◽  
Convex Surface ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Future Research ◽  
Two Dimensional ◽  
Thematic Maps ◽  
Research Directions ◽  
Future Research Directions ◽  
The Many

The theory of cartographic projections is a tool which can present the convex surface of the Earth on the plane. Of the many types of maps, thematic maps perform an important function due to the wide possibilities of adapting their content to current needs. The limitation of classic maps is their two-dimensional nature. In the era of rapidly growing methods of mass acquisition of spatial data, the use of flat images is often not enough to reveal the level of complexity of certain objects. In this case, it is necessary to use visualization in three-dimensional space. The motivation to conduct the study was the use of cartographic projections methods, spatial transformations, and the possibilities offered by thematic maps to create thematic three-dimensional map imaging (T3DMI). The authors presented a practical verification of the adopted methodology to create a T3DMI visualization of the marina of the National Sailing Centre of the Gdańsk University of Physical Education and Sport (Poland). The profiled characteristics of the object were used to emphasize the key elements of its function. The results confirmed the increase in the interpretative capabilities of the T3DMI method, relative to classic two-dimensional maps. Additionally, the study suggested future research directions of the presented solution.

scholarly journals Special Issue: Application of Extracellular Matrix in Regenerative Medicine

2021 ◽  
Vol 11 (7) ◽  
pp. 3262
Author(s):  
Neill J. Turner
Keyword(s):  
Extracellular Matrix ◽  
Regenerative Medicine ◽  
Wound Repair ◽  
Three Dimensional ◽  
Dynamic Structure ◽  
Scaffold Material ◽  
Special Issue ◽  
Organ Regeneration ◽  
Scaffold Materials ◽  
The Many

The present Special Issue comprises a collection of articles addressing the many ways in which extracellular matrix (ECM), or its components parts, can be used in regenerative medicine applications. ECM is a dynamic structure, composed of a three-dimensional architecture of fibrous proteins, proteoglycans, and glycosaminoglycans, synthesized by the resident cells. Consequently, ECM can be considered as nature’s ideal biologic scaffold material. The articles in this Special Issue cover a range of topics from the use of ECM components to manufacture scaffold materials, understanding how changes in ECM composition can lead to the development of disease, and how decellularization techniques can be used to develop tissue-derived ECM scaffolds for whole organ regeneration and wound repair. This editorial briefly summarizes the most interesting aspects of these articles.

scholarly journals Data-Informed Decomposition for Localized Uncertainty Quantification of Dynamical Systems

Vibration ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 49-63
Author(s):  
Waad Subber ◽  
Sayan Ghosh ◽  
Piyush Pandita ◽  
Yiming Zhang ◽  
Liping Wang
Keyword(s):  
Dynamical Systems ◽  
Computational Cost ◽  
Three Dimensional ◽  
Region Of Interest ◽  
System Response ◽  
Computational Domain ◽  
User Interest ◽  
Numerical Resolution ◽  
Multi Scale ◽  
Operation Conditions

Industrial dynamical systems often exhibit multi-scale responses due to material heterogeneity and complex operation conditions. The smallest length-scale of the systems dynamics controls the numerical resolution required to resolve the embedded physics. In practice however, high numerical resolution is only required in a confined region of the domain where fast dynamics or localized material variability is exhibited, whereas a coarser discretization can be sufficient in the rest majority of the domain. Partitioning the complex dynamical system into smaller easier-to-solve problems based on the localized dynamics and material variability can reduce the overall computational cost. The region of interest can be specified based on the localized features of the solution, user interest, and correlation length of the material properties. For problems where a region of interest is not evident, Bayesian inference can provide a feasible solution. In this work, we employ a Bayesian framework to update the prior knowledge of the localized region of interest using measurements of the system response. Once, the region of interest is identified, the localized uncertainty is propagate forward through the computational domain. We demonstrate our framework using numerical experiments on a three-dimensional elastodynamic problem.

Molecular Dynamics Simulations of High Energy Cascades in Iron

1994 ◽  
Vol 373 ◽  
Author(s):  
Roger E. Stoller
Keyword(s):  
Molecular Dynamics ◽  
Three Dimensional ◽  
High Energy ◽  
Dynamics Simulation ◽  
Method Of Molecular Dynamics ◽  
Energy Cascades ◽  
Iron Based ◽  
The Many ◽  
Property Changes ◽  
Dynamics Simulations

AbstractA series of high-energy, up to 20 keV, displacement cascades in iron have been investigated for times up to 200 ps at 100 K using the method of molecular dynamics simulation. Thesimulations were carried out using the MOLDY code and a modified version of the many-bodyinteratomic potential developed by Finnis and Sinclair. The paper focuses on those results obtained at the highest energies, 10 and 20 keV. The results indicate that the fraction of the Frenkel pairs surviving in-cascade recombination remains fairly high in iron and that the fraction of the surviving point defects that cluster is lower than in materials such as copper. In particular, vacancy clustering appears to be inhibited in iron. Some of the interstitial clusters were observed to exhibit an unexpectedly complex, three-dimensional morphology. The observations are discussed in terms of their relevance to microstructural evolution and mechanical property changes in irradiated iron-based alloys.

Three-Dimensional Parametric Finite-Volume Homogenization of Periodic Materials with Multi-Scale Structural Applications

2018 ◽  
Vol 10 (04) ◽  
pp. 1850045 ◽  
Author(s):  
Qiang Chen ◽  
Guannan Wang ◽  
Xuefeng Chen
Keyword(s):  
Finite Volume ◽  
Three Dimensional ◽  
Functionally Graded ◽  
Attractive Alternative ◽  
Matrix Assembly ◽  
Functionally Graded Composite ◽  
Multi Scale ◽  
Hexahedral Elements ◽  
Stiffness Matrices ◽  
Structural Applications

In order to satisfy the increasing computational demands of micromechanics, the Finite-Volume Direct Averaging Micromechanics (FVDAM) theory is developed in three-dimensional (3D) domain to simulate the multiphase heterogeneous materials whose microstructures are distributed periodically in the space. Parametric mapping, which endorses arbitrarily shaped and oriented hexahedral elements in the microstructure discretization, is employed in the unit cell solution. Unlike the finite-element (FE) technique, the expressions for local stiffness matrices are derived explicitly, enabling efficient global stiffness matrix assembly using an easily implementable algorithm. To demonstrate the accuracy and efficiency of the proposed theory, the homogenized moduli and localized stress distributions produced by the FE analyses are given for comparisons, where excellent agreement is always obtained for the 3D microstructures with different geometrical and material properties. Finally, a multi-scale stress analysis of functionally graded composite cylinders is conducted. This extension further increases the FVDAM’s range of applicability and opens new opportunities for pursuing other areas, providing an attractive alternative to the FE-based approaches that may be compared.

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