Distinguishing the Brazilian mangrove species Avicennia germinans and A. schaueriana (Acanthaceae) by elliptic Fourier analysis of leaf shape

Mangrove forests have declined worldwide and understanding the key drivers of regeneration at different perturbation levels can help manage and preserve these critical ecosystems. For example, the Ramsar site # 1602, located at the Tampamachoco lagoon, Veracruz, México, consists of a dense forest of medium-sized trees composed of three mangrove species. Due to several human activities, including the construction of a power plant around the 1990s, an area of approximately 2.3 km2 has suffered differential levels of perturbation: complete mortality, partial tree loss (divided into two sections: main and isolated patch), and apparently undisturbed sites. The number and size of trees, from seedlings to adults, were measured using transects and quadrats. With a matrix of the abundance of trees by size categories and species, an ordination (nMDS) showed three distinct groups corresponding to the degree of perturbation. Projection matrices based on the size structure of Avicennia germinans showed transition probabilities that varied according to perturbation levels. Lambda showed growing populations except on the zone that showed partial tree loss; a relatively high abundance of seedlings is not enough to ensure stable mangrove dynamics or start regeneration; and the survival of young trees and adult trees showed high sensitivity.

Download Full-text

Foot asymmetry in healthy adults: Elliptic fourier analysis of standardized footprints

Journal of Orthopaedic Research® ◽

10.1002/jor.1100160619 ◽

1998 ◽

Vol 16 (6) ◽

pp. 758-765 ◽

Cited By ~ 16

Author(s):

Chiarella Sforza ◽

Giovanni Michielon ◽

Nicola Fragnito ◽

Virgilio F. Ferrario

Keyword(s):

Fourier Analysis ◽

Healthy Adults ◽

Elliptic Fourier Analysis ◽

Foot Asymmetry

Download Full-text

Description and Quantification of Sexual Dimorphism of Pubic Body Shape in Hispanic Populations Using Elliptic Fourier Analysis

Forensic Anthropology ◽

10.5744/fa.2020.0017 ◽

2021 ◽

Author(s):

Erica Cantor ◽

Krista Latham ◽

Stephen Nawrocki

Keyword(s):

Fourier Analysis ◽

North American ◽

Principal Component ◽

Pubic Bone ◽

Biological Traits ◽

Sex Estimation ◽

Age At Death ◽

Elliptic Fourier Analysis ◽

Hispanic Populations ◽

Effective Principal

Sex estimation is important in the creation of a biological profile for unidentified human remains, as positive identification cannot occur until the decedent’s biological traits have been determined and the range of possible matches has been narrowed. The pubic bone is cited as one of the best indicators of sex due to the constraints of childbirth. Current methods that use the pubic bone for sex estimation, however, rely on poorly defined and subjective observations that are susceptible to inter-and intraobserver error. Additionally, many of the methods currently in use are based on North American populations and thus may not necessarily model the variation seen in other populations around the globe. The aim of this study is to gain a better understanding of variation in pubic bone shape in Hispanic populations by separating the influences of sex, ancestry, and age at death. A total of 164 pubic bones from North American Hispanic and Chilean individuals were compared to 287 pubic bones from individuals of Euro-American ancestry from North American collections, using Elliptic Fourier analysis (EFA) of photographs, principal component analysis, and ANCOVA. EFA generated five effective principal components that collectively describe approximately 95% of the variation in the shape of the pubic body. Sex, age at death, and ancestry were all found to significantly influence shape but explained only 25% of the overall variation. The remaining 75% is likely influenced by variables that cannot be controlled for in anthropological analysis, underscoring how little variance in skeletal morphology is actually explainable.

Download Full-text

Describing shell shapes of Venerid bivalves using elliptic fourier analysis

International Journal of Biosciences (IJB) ◽

10.12692/ijb/12.1.82-89 ◽

2018 ◽

Vol 12 (1) ◽

pp. 82-89

Keyword(s):

Fourier Analysis ◽

Elliptic Fourier Analysis

Download Full-text

Shape difference of mud clasts depending on depositional facies: application of newly modified elliptic Fourier analysis to hybrid event beds

Journal of Sedimentary Research ◽

10.2110/jsr.2020.67 ◽

2020 ◽

Vol 90 (10) ◽

pp. 1410-1435

Author(s):

Sojiro Fukuda ◽

Hajime Naruse

Keyword(s):

Fourier Analysis ◽

Shape Analysis ◽

Transport Processes ◽

Transport Systems ◽

Shape Parameters ◽

Elliptic Fourier Analysis ◽

Depositional Facies ◽

Size And Shape ◽

Muddy Sediments ◽

Hybrid Event

ABSTRACT Hybrid event beds are the deposits from sediment gravity flows that change their rheological behavior through their passage, entraining muddy sediments and damping turbulence. Muddy facies of hybrid event beds are often associated with abundant mud clasts which show a wide variety of size and shape. The variation of clast occurrence in hybrid event beds is expected to preserve the information of entrainment and transport processes of muddy sediments in submarine density currents. However, previous analyses of hybrid event beds have focused on describing the overall clast occurrence rather than the statistical size and shape analyses because traditional shape parameters are incapable of characterizing the complex shape of mud clasts. Here, a new quantitative grain-shape analysis of mud clasts is conducted and allows visualization of the spatial variation of clast size and shape, which suggests the wide variety of origin and transport systems of entrained mud clasts. This new method revises the traditional elliptic Fourier analysis, substituting Fourier power spectra (FPS) for traditional elliptic Fourier descriptors to overcome the mirror-wise shape problem. Further, principal-component analysis is shown to capture significant shape attributes more effectively than traditional shape parameters. The proposed method is applied to mud clasts in sediment-gravity-flow deposits in the lower Pleistocene Otadai Formation, central Japan. Results imply that there are distinctive shape and size differences of mud clasts that are strongly associated with depositional facies rather than the distance from the source. The clasts have a higher angularity than other facies in the debrite intervals in hybrid event beds. It is also shown that clasts in sandy, structureless facies have different characteristics in shapes based on elongation and convexity compared to laminated facies. Comparison between different shape-analysis methods demonstrates that none of the traditional methods are able to visualize these trends as effectively as the method presented herein. These results highlight the importance of the quantitative shape analysis of sediment grains and the effectiveness of FPS-based elliptic Fourier analysis.

Download Full-text