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Geometric morphometry

Bruna Demari-Silva, Laura Cristina Multini, Lincoln Suesdek, Tatiane M P Oliveira, Maria Anice Mureb Sallum, Mauro Toledo Marrelli
Culex coronator Dyar and Knab and Culex usquatus Dyar belong to the Coronator Group of the subgenus Culex. Culex coronator and Cx. usquatus are widespread and sympatric throughout their distribution range, which includes Brazil. Morphological identification of these species is based primarily on the characteristics of the male genitalia; females are indistinguishable using the qualitative characteristics employed in identification keys. The primary objective of this study was to distinguish females of Cx. coronator from those of Cx...
March 23, 2017: Journal of Medical Entomology
Jie Zhang, Jie Shi, Cynthia Stonnington, Qingyang Li, Boris A Gutman, Kewei Chen, Eric M Reiman, Richard J Caselli, Paul M Thompson, Jieping Ye, Yalin Wang
Mild Cognitive Impairment (MCI) is a transitional stage between normal age-related cognitive decline and Alzheimer's disease (AD). Here we introduce a hyperbolic space sparse coding method to predict impending decline of MCI patients to dementia using surface measures of ventricular enlargement. First, we compute diffeomorphic mappings between ventricular surfaces using a canonical hyperbolic parameter space with consistent boundary conditions and surface tensor-based morphometry is computed to measure local surface deformations...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
Dimitrios P Sokolis, Despoina C Petsepe, Stavroula A Papadodima, Stavros K Kourkoulis
The ureter has been largely overlooked heretofore in the study of the biomechanics of soft biological tissues, although there has been significant motivation to use its biomechanical properties as inputs to mathematical models of ureteral function. Herein, we used histological analysis for quantification of collagen contents and thickness/area of ureteral layers, with concomitant geometrical analysis of zero-stress and no-load states, and inflation/extension testing to biomechanically characterize with the Fung-type model the ureters from cadavers...
January 25, 2017: Journal of Biomechanics
Jennifer A McKenzie, Evan Buettmann, Adam C Abraham, Michael J Gardner, Matthew J Silva, Megan L Killian
Scleraxis (Scx) is a known regulator of tendon development, and recent work has identified the role of Scx in bone modeling. However, the role of Scx in fracture healing has not yet been explored. This study was conducted to identify the role of Scx in cortical bone development and fracture healing. Scx green fluorescent protein-labeled (ScxGFP) reporter and Scx-knockout (Scx-mutant) mice were used to assess bone morphometry and the effects of fracture healing on Scx localization and gene expression, as well as callus healing response...
March 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Javier Irurita Olivares, Inmaculada Alemán Aguilera
In the context of physical and forensic anthropology, when a child's skeleton is damaged or in poor condition, which is common, many of the metric methods for the estimation of skeletal age cannot be used. In these circumstances, those more resistant bones, such as the pars basilaris, will be most useful. The aims of this study were to test existing methods for estimating skeletal age from the metric study of the pars basilaris and to propose new regression formulae. One hundred fourteen individuals aged between 5 months of gestation and 6 years were analyzed; seven measures were taken from each pars basilaris using a digital caliper...
October 27, 2016: International Journal of Legal Medicine
M Dadáková, V Cagáňová, J Dupej, E Hoffmannová, J Borský, J Velemínská
PURPOSE: To evaluate the facial morphology of pre-school patients with various types of orofacial cleft after neonatal cheiloplasty in pre-school aged children; and to compare facial variability and mean shape with age-corresponding healthy controls. MATERIALS AND METHODS: The sample included 40 patients with unilateral cleft lip (CL), 22 patients with unilateral cleft lip and palate (UCLP), and 10 patients with bilateral cleft lip and palate (BCLP). Patients were divided into two age categories, with a mean age of 3 years and 4...
September 2016: Journal of Cranio-maxillo-facial Surgery
Ljiljana Šašić, Jelena Ačanski, Ante Vujić, Gunilla Ståhls, Snežana Radenković, Dubravka Milić, Dragana Obreht Vidaković, Mihajla Đan
The Merodon aureus species group (Diptera: Syrphidae: Eristalinae) comprises a number of different sub-groups and species complexes. In this study we focus on resolving the taxonomic status of the entity previously identified as M. cinereus B, here identified as M. atratus species complex. We used an integrative approach based on morphological descriptions, combined with supporting characters that were obtained from molecular analyses of the mitochondrial cytochrome c oxidase I gene as well as from geometric morphometry of wing and surstylus shapes and environmental niche comparisons...
2016: PloS One
Junbin Huang, He Liu, Defeng Wang, James F Griffith, Lin Shi
OBJECTIVE: The purpose of our study is to give a relatively objective definition of talar dome and its shape approximations to sphere (SPH), cylinder (CLD) and bi-truncated cone (BTC). MATERIALS AND METHODS: The "talar dome" is well-defined with the improved Dijkstra's algorithm, considering the Euclidean distance and surface curvature. The geometric similarity between talar dome and ideal shapes, namely SPH, CLD and BTC, is quantified. 50 unilateral CT datasets from 50 subjects with no pathological morphometry of tali were included in the experiments and statistical analyses were carried out based on the approximation error...
April 2017: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
Beatriz Gamarra, Mónica Nova Delgado, Alejandro Romero, Jordi Galbany, Alejandro Pérez-Pérez
Morphology has been widely used for inferring the phylogenies of numerous taxonomic groups. Recent molecular studies performed on extant non-human primates, however, have cast doubt on the reliability of cranial and postcranial characters for characterizing evolutionary affinities. Because molecular evidence is often not available for fossil specimens, detecting phylogenetic signals in anatomical features is of great relevance. Here we have analyzed molar (M1 and M2) crown shape by means of geometric morphometrics in a large sample of both extant and fossil Miocene catarrhine primates to detect the phylogenetic signal in molar morphometry...
May 2016: Journal of Human Evolution
C A Bulant, P J Blanco, T P Lima, A N Assunção, G Liberato, J R Parga, L F R Ávila, A C Pereira, R A Feijóo, P A Lemos
This work presents a computational framework to perform a systematic and comprehensive assessment of the morphometry of coronary arteries from in vivo medical images. The methodology embraces image segmentation, arterial vessel representation, characterization and comparison, data storage, and finally analysis. Validation is performed using a sample of 48 patients. Data mining of morphometric information of several coronary arteries is presented. Results agree to medical reports in terms of basic geometric and anatomical variables...
May 11, 2016: International Journal for Numerical Methods in Biomedical Engineering
Jaeil Kim, Maria del C Valdés Hernández, Natalie A Royle, Susana Muñoz Maniega, Benjamin S Aribisala, Alan J Gow, Mark E Bastin, Ian J Deary, Joanna M Wardlaw, Jinah Park
BACKGROUND: Structural changes of the brain's third ventricle have been acknowledged as an indicative measure of the brain atrophy progression in neurodegenerative and endocrinal diseases. To investigate the ventricular enlargement in relation to the atrophy of the surrounding structures, shape analysis is a promising approach. However, there are hurdles in modeling the third ventricle shape. First, it has topological variations across individuals due to the inter-thalamic adhesion. In addition, as an interhemispheric structure, it needs to be aligned to the midsagittal plane to assess its asymmetric and regional deformation...
June 2016: Computer Methods and Programs in Biomedicine
Allison P Gremba, Seth M Weinberg, J Douglas Swarts, Margaretha L Casselbrant
OBJECTIVES: Past studies using traditional morphometric approaches have reported a handful of differences in craniofacial dimensions between individuals with and without otitis media (OM). In this study, a geometric morphometry (GM) approach was used to determine if craniofacial shape is different among children with no history of OM and a history of recurrent acute OM (RAOM) at two different ages. METHODS: Nineteen standard landmarks were identified on lateral cephalometric radiographs from 79 children (41 Control, 38 RAOM) at 4 years and 52 children (27 Control, 25 RAOM) at 6 years of age...
May 2016: International Journal of Pediatric Otorhinolaryngology
Alice Ching Ching Lau, Masakazu Asahara, Sung Yong Han, Junpei Kimura
Sexual dimorphism of the craniodental morphology of the Eurasian otter in South Korea was studied with geometric morphometrics. 29 adult skulls (15 males and 14 females) were used. Images of the dorsal and ventral view of the cranium and right lateral view of the mandible were taken and then digitized, and measurements were taken on the right side. Results showed that size difference between males and females was significant. Correlations between the size and shape variations have not been observed in this study...
July 1, 2016: Journal of Veterinary Medical Science
Tsung Fei Khang, Oi Yoon Michelle Soo, Wooi Boon Tan, Lee Hong Susan Lim
Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions. Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia...
2016: PeerJ
Ruoliang Tang, Celal Gungor, Richard F Sesek, Kenneth Bo Foreman, Sean Gallagher, Gerard A Davis
PURPOSE: Variability of the human lower lumbar geometry is related to complications of disc arthroplasty surgery. Accurate morphometric descriptions are essential for the design of artificial intervertebral discs to ensure good prothesis-vertebra contact and better load distribution, and can improve spinal biomechanics. Unfortunately, current knowledge of the lower lumbar geometry is limited either in the representativeness of sample populations or the accuracy and comprehensiveness of measurements...
February 12, 2016: European Spine Journal
Zs Bräger, T Moritz, A C Tsikliras, J Gonzalvo, M Radulović, Á Staszny
Landmark-based geometric morphometric analysis revealed differences in scale shape between European sardine Sardina pilchardus and round sardinella Sardinella aurita as well as among the local populations of each species. Fish scale measurements from four different areas in the central and eastern Mediterranean Sea showed that the mean scale shape of the two species using landmark data could be differentiated with high certainty. Populations of S. aurita from the central and eastern Mediterranean Sea could be separated reliably (P < 0·001) with an average discrimination rate of 91%, whereas the average discrimination of the S...
March 2016: Journal of Fish Biology
Bridget F B Algee-Hewitt, Amber D Wheat
OBJECTIVES: The use of geometric morphometry to study cranial variation has steadily grown in appeal over the past decade in biological anthropology. Publication trends suggest that the most popular methods for three-dimensional data acquisition involve landmark-based coordinate data collection using a digitizer. Newer laser scan approaches are seeing increasing use, owing to the benefits that densely sampled data offer. While both of these methods have their utility, research that investigates their compatibility is lacking...
May 2016: American Journal of Physical Anthropology
Ambrosio Torres, Daniel R Miranda-Esquivel
We evaluated the directional asymmetry between right and left wings and quantified the intraspecific and interspecific variation of the wing shape of 601 specimens of the genus Diachlorus to determine to what extent the geometrical variation discriminates six species distributed in six protected areas of Colombia. Geometric analyses were performed, integrating Procrustes methods, principal component analyses, cluster analyses, linear and quadratic discriminant analyses, and evaluations of shape changes. In Diachlorus, left and right wings did not present significant asymmetry but a geometrical analysis was allowed for species identification and, in some cases, the origin of the specimens using the variation of wing shape; the best-assigned species was Diachlorus leticia Wilkerson & Fairchild, while the worst was Diachlorus jobbinsi Fairchild, which also had the highest intraspecific variation, while Diachlorus fuscistigma Lutz had the lowest variation...
April 2016: Neotropical Entomology
Yong-Jin Liu
The skeleton of a 2D shape is an important geometric structure in pattern analysis and computer vision. In this paper we study the skeleton of a 2D shape in a two-manifold M , based on a geodesic metric. We present a formal definition of the skeleton S(Ω) for a shape Ω in M and show several properties that make S(Ω) distinct from its Euclidean counterpart in R(2). We further prove that for a shape sequence {Ωi} that converge to a shape Ω in M, the mapping Ω→ S̅(Ω) is lower semi-continuous. A direct application of this result is that we can use a set P of sample points to approximate the boundary of a 2D shape Ω, and the Voronoi diagram of P inside Ω ⊂ M gives a good approximation to the skeleton S(Ω) ...
September 2015: IEEE Transactions on Pattern Analysis and Machine Intelligence
Moises Thiago de Souza Freitas, Claudia Maria Ríos-Velasquez, César Raimundo Lima Costa, Carlos Alberto Santiago Figueirêdo, Nádia Consuelo Aragão, Lidiane Gomes da Silva, Marcus Vinicius de Aragão Batista, Teresa Cristina Leal Balbino, Felipe Arley Costa Pessoa, Valdir de Queiroz Balbino
BACKGROUND: In South America, Lutzomyia umbratilis is the main vector of Leishmania guyanensis, one of the species involved in the transmission of American tegumentary leishmaniasis. In Brazil, L. umbratilis has been recorded in the Amazon region, and in the state of Pernambuco, Northeastern region, where an isolated population has been identified. This study assessed the phylogeographic structure and size and shape differences of the wing of three Brazilian populations. METHODS: Samples of L...
2015: Parasites & Vectors
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