An Assessment of the Impact of Resharpening on Paleoindian Projectile Point Blade Shape Using Geometric Morphometric Techniques

2010 ◽  
pp. 255-273 ◽  
Author(s):  
Briggs Buchanan ◽  
Mark Collard
Keyword(s):  
Geometric Morphometric ◽  
Projectile Point ◽  
Blade Shape ◽  
The Impact

Affordable Uncertainty Quantification for Industrial Problems: Application to Aero-Engine Fans

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Tiziano Ghisu ◽  
Shahrokh Shahpar
Keyword(s):  
Uncertainty Quantification ◽  
Uncertainty Distribution ◽  
Blade Shape ◽  
Shape Uncertainty ◽  
Column Pivoting ◽  
The Cost ◽  
Sparse Grid Quadrature ◽  
The Impact ◽  
The Given ◽  
Bypass Ratio

Uncertainty quantification (UQ) is an increasingly important area of research. As components and systems become more efficient and optimized, the impact of uncertain parameters is likely to become critical. It is fundamental to consider the impact of these uncertainties as early as possible during the design process, with the aim of producing more robust designs (less sensitive to the presence of uncertainties). The cost of UQ with high-fidelity simulations becomes therefore of fundamental importance. This work makes use of least-squares approximations in the context of appropriately selected polynomial chaos (PC) bases. An efficient technique based on QR column pivoting has been employed to reduce the number of evaluations required to construct the approximation, demonstrating the superiority of the method with respect to full-tensor quadrature (FTQ) and sparse-grid quadrature (SGQ). Orthonormal polynomials used for the PC expansion are calculated numerically based on the given uncertainty distribution, making the approach optimal for any type of input uncertainty. The approach is used to quantify the variability in the performance of two large bypass-ratio jet engine fans in the presence of shape uncertainty due to possible manufacturing processes. The impacts of shape uncertainty on the two geometries are compared, and sensitivities to the location of the blade shape variability are extracted. The mechanisms at the origin of the change in performance are analyzed in detail, as well as the differences between the two configurations.

scholarly journals Comparative analysis of squamate brains unveils multi-level variation in cerebellar architecture associated with locomotor specialization

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Simone Macrì ◽  
Yoland Savriama ◽  
Imran Khan ◽  
Nicolas Di-Poï
Keyword(s):  
Cortical Neurons ◽  
Strong Predictor ◽  
3D Models ◽  
Volumetric Analysis ◽  
High Definition ◽  
Geometric Morphometric ◽  
Vertebrate Brain ◽  
Multi Level ◽  
Shape Characters ◽  
The Impact

AbstractEcomorphological studies evaluating the impact of environmental and biological factors on the brain have so far focused on morphology or size measurements, and the ecological relevance of potential multi-level variations in brain architecture remains unclear in vertebrates. Here, we exploit the extraordinary ecomorphological diversity of squamates to assess brain phenotypic diversification with respect to locomotor specialization, by integrating single-cell distribution and transcriptomic data along with geometric morphometric, phylogenetic, and volumetric analysis of high-definition 3D models. We reveal significant changes in cerebellar shape and size as well as alternative spatial layouts of cortical neurons and dynamic gene expression that all correlate with locomotor behaviours. These findings show that locomotor mode is a strong predictor of cerebellar structure and pattern, suggesting that major behavioural transitions in squamates are evolutionarily correlated with mosaic brain changes. Furthermore, our study amplifies the concept of ‘cerebrotype’, initially proposed for vertebrate brain proportions, towards additional shape characters.

scholarly journals Loeys-Dietz and Shprintzen-Goldberg syndromes: analysis of TGF-β-opathies with craniofacial manifestations using an innovative multimodality method

2021 ◽  
pp. jmedgenet-2021-107695
Author(s):  
Konstantinia Almpani ◽  
Denise K. Liberton ◽  
Priyam Jani ◽  
Cyrus Keyvanfar ◽  
Rashmi Mishra ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Cranial Base ◽  
Temporomandibular Joint Disorders ◽  
Geometric Morphometric ◽  
Pharyngeal Airway ◽  
Anterior Cranial Base ◽  
Obstructive Sleep ◽  
Functional Features ◽  
Maxilla And Mandible ◽  
The Impact

BackgroundElevated transforming growth factor-beta (TGF-β) signalling has been implicated in the pathogenesis of Loeys-Dietz syndrome (LDS) and Shprintzen-Goldberg syndrome (SGS). In this study, we provide a qualitative and quantitative analysis of the craniofacial and functional features among the LDS subtypes and SGS.MethodsWe explore the variability within and across a cohort of 44 patients through deep clinical phenotyping, three-dimensional (3D) facial photo surface analysis, cephalometric and geometric morphometric analyses of cone-beam CT scans.ResultsThe most common craniofacial features detected in this cohort include mandibular retrognathism (84%), flat midface projection (84%), abnormal eye shape (73%), low-set ears (73%), abnormal nose (66%) and lip shape (64%), hypertelorism (41%) and a relatively high prevalence of nystagmus/strabismus (43%), temporomandibular joint disorders (38%) and obstructive sleep apnoea (23%). 3D cephalometric analysis demonstrated an increased cranial base angle with shortened anterior cranial base and underdevelopment of the maxilla and mandible, with evidence of a reduced pharyngeal airway in 55% of those analysed. Geometric morphometric analysis confirmed that the greatest craniofacial shape variation was among patients with LDS type 2, with distinct clustering of patients with SGS.ConclusionsThis comprehensive phenotypic approach identifies developmental abnormalities that segregate to mutation variants along the TGF-β signalling pathway, with a particularly severe phenotype associated with TGFBR2 and SKI mutations. Multimodality assessment of craniofacial anomalies objectively reveals the impact of mutations of the TGF-β pathway with perturbations associated with the cranium and cranial base with severe downstream effects on the orbit, maxilla and mandible with the resultant clinical phenotypes.

scholarly journals Urbanisation and wing asymmetry in the western honey bee (Apis mellifera, Linnaeus 1758) at multiple scales

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5940 ◽  
Author(s):  
Ryan J. Leonard ◽  
Katie K.Y. Wat ◽  
Clare McArthur ◽  
Dieter F. Hochuli
Keyword(s):  
Apis Mellifera ◽  
Land Cover ◽  
Honey Bee ◽  
Multiple Scales ◽  
Spatial Scales ◽  
Wing Shape ◽  
Phenotypic Traits ◽  
Wing Size ◽  
Geometric Morphometric ◽  
The Impact

Changes in the mean and variance of phenotypic traits like wing and head morphology are frequently used as indicators of environmental stress experienced during development and may serve as a convenient index of urbanization exposure. To test this claim, we collected adult western honey bee (Apis mellifera Linnaeus 1758, Hymenoptera, Apidae) workers from colonies located across an urbanization gradient, and quantified associations between the symmetries of both wing size and wing shape, and several landscape traits associated with urbanization. Landscape traits were assessed at two spatial scales (three km and 500 m) and included vegetation and anthropogenic land cover, total road length, road proximity and, population and dwelling density. We then used geometric morphometric techniques to determine two wing asymmetry scores—centroid size, a measure of wing size asymmetry and Procrustes distance, a measure of wing shape asymmetry. We found colony dependent differences in both wing size and shape asymmetry. Additionally, we found a negative association between wing shape asymmetry and road proximity at the three km buffer, and associations between wing shape asymmetry and road proximity, anthropogenic land cover and vegetation cover at the 500 m buffer. Whilst we were unable to account for additional variables that may influence asymmetry including temperature, pesticide presence, and parasitism our results demonstrate the potential usefulness of wing shape asymmetry for assessing the impact of certain landscape traits associated with urbanization. Furthermore, they highlight important spatial scale considerations that warrant investigation in future phenotypic studies assessing urbanization impact.

scholarly journals Ischiofemoral impingement: the evolutionary cost of pelvic obstetric adaptation

2021 ◽  
Author(s):  
E A Audenaert ◽  
K Duquesne ◽  
J De Roeck ◽  
T Mutsvangwa ◽  
B Borotikar ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Clinical Syndrome ◽  
Monte Carlo Experiment ◽  
Geometric Morphometric ◽  
Hip Morphology ◽  
Statistical Shape ◽  
Ischiofemoral Space ◽  
The Impact ◽  
Gender Specific ◽  
Ischiofemoral Impingement

Abstract The risk for ischiofemoral impingement has been mainly related to a reduced ischiofemoral distance and morphological variance of the femur. From an evolutionary perspective, however, there are strong arguments that the condition may also be related to sexual dimorphism of the pelvis. We, therefore, investigated the impact of gender-specific differences in anatomy of the ischiofemoral space on the ischiofemoral clearance, during static and dynamic conditions. A random sampling Monte-Carlo experiment was performed to investigate ischiofemoral clearance during stance and gait in a large (n = 40 000) virtual study population, while using gender-specific kinematics. Subsequently, a validated gender-specific geometric morphometric analysis of the hip was performed and correlations between overall hip morphology (statistical shape analysis) and standard discrete measures (conventional metric approach) with the ischiofemoral distance were evaluated. The available ischiofemoral space is indeed highly sexually dimorphic and related primarily to differences in the pelvic anatomy. The mean ischiofemoral distance was 22.2 ± 4.3 mm in the females and 29.1 ± 4.1 mm in the males and this difference was statistically significant (P < 0.001). Additionally, the ischiofemoral distance was observed to be a dynamic measure, and smallest during femoral extension, and this in turn explains the clinical sign of pain in extension during long stride walking. In conclusion, the presence of a reduced ischiofemroal distance and related risk to develop a clinical syndrome of ischiofemoral impingement is strongly dominated by evolutionary effects in sexual dimorphism of the pelvis. This should be considered when female patients present with posterior thigh/buttock pain, particularly if worsened by extension. Controlled laboratory study.

scholarly journals Craniofacial Analysis May Indicate Co-Occurrence of Skeletal Malocclusions and Associated Risks in Development of Cleft Lip and Palate

2020 ◽  
Vol 8 (1) ◽  
pp. 2 ◽  
Author(s):  
Denise K. Liberton ◽  
Payal Verma ◽  
Konstantinia Almpani ◽  
Peter W. Fung ◽  
Rashmi Mishra ◽  
...  
Keyword(s):  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Morphological Changes ◽  
Principal Component ◽  
Craniofacial Morphology ◽  
Geometric Morphometric ◽  
Dentofacial Deformities ◽  
Dentofacial Deformity ◽  
Maxilla And Mandible ◽  
The Impact

Non-syndromic orofacial clefts encompass a range of morphological changes affecting the oral cavity and the craniofacial skeleton, of which the genetic and epigenetic etiologic factors remain largely unknown. The objective of this study is to explore the contribution of underlying dentofacial deformities (also known as skeletal malocclusions) in the craniofacial morphology of non-syndromic cleft lip and palate patients (nsCLP). For that purpose, geometric morphometric analysis was performed using full skull cone beam computed tomography (CBCT) images of patients with nsCLP (n = 30), normocephalic controls (n = 60), as well as to sex- and ethnicity- matched patients with an equivalent dentofacial deformity (n = 30). Our outcome measures were shape differences among the groups quantified via principal component analysis and associated principal component loadings, as well as mean shape differences quantified via a Procrustes distance among groups. According to our results, despite the shape differences among all three groups, the nsCLP group shares many morphological similarities in the maxilla and mandible with the dentofacial deformity group. Therefore, the dentoskeletal phenotype in nsCLP could be the result of the cleft and the coexisting dentofacial deformity and not simply the impact of the cleft.

scholarly journals Phylogenetic analysis of stemmed points from Patagonia: Shape change and morphospace evolution

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Marcelo Cardillo ◽  
Judith Charlin
Keyword(s):  
Phylogenetic Analysis ◽  
Shape Change ◽  
Spatial Distance ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Projectile Point ◽  
Projectile Points ◽  
Spatial Coverage ◽  
Shape Characters ◽  
Extreme North

This work is focused in the study of Patagonian lithic projectile points shape variation from a phylogenetic perspective pursuing three main aims: first, generate a model of projectile point shape diversification and morphospace evolution; second, estimate shape variation through time, and finally, assess the robustness of previous results using the same methods but in a larger sample with better spatial coverage. A previous work using geometric morphometric and cladistic methods suggested a pattern of general morphological diversification across Patagonia related, at least in part, to the spatial distance between cases, distinguishing two main clades in northern (43-45° S) and southern (50-52° S) Patagonia. In the present work to study this pattern in a more detailed level, a sample of ca. 1200 projectile points was used to obtain statistically different morphological classes performing unsupervised K-means searching. Shape characters were used to describe the different taxonomic units and to perform the phylogenetic analysis (through the Neighbor Joining and Maximun Parsimony methods) using as an ancestor the earliest point type known to the region (Fishtail point). The new results suggest that projectile points with longer and narrow blades and smaller stems evolved later in Patagonia and occupy a different sector of morphospace that could be related to the emergence of different technical systems, like the bow and arrow. However, these results do not support the previous ones of a projectile point diversification pattern mediated by spatial distance, maybe due to the reduction of contrast between the extreme north and south of Patagonia by the larger spatial coverage used in the present analysis.

scholarly journals Still slow, but even steadier: an update on the evolution of turtle cranial disparity interpolating shapes along branches

2017 ◽  
Vol 4 (11) ◽  
pp. 170899 ◽  
Author(s):  
Christian Foth ◽  
Eduardo Ascarrunz ◽  
Walter G. Joyce
Keyword(s):  
Environmental Changes ◽  
Geometric Morphometric ◽  
Original Dataset ◽  
Branch Lengths ◽  
Apparent Correlation ◽  
Extinction Event ◽  
Extinction Events ◽  
A Minor ◽  
The Impact ◽  
Early Cenozoic

In a previous study, we estimated the cranial disparity of turtles (Testudinata) through time using geometric morphometric data from both terminal taxa and hypothetical ancestors to compensate for temporal gaps in the fossil record. While this method yielded reasonable results for the Mesozoic and the early Cenozoic, we found a large drop in cranial disparity for the Miocene, for which we found no correlation with known environmental changes or extinction events. Instead, we speculated that the Miocene dip was a result of poor sampling of fossils or ancestors in this time bin. To countervail this problem, we here updated our original dataset and interpolated changes of shape along the branch lengths and compared them with the previous data. We furthermore explored the impact of topological and temporal uncertainty, demonstrating that the Miocene dip, indeed, is a sampling artefact. All remaining conclusions of the previous study could be more or less supported, nevertheless, including an apparent correlation with global biogeographic events, a minor correlation between cranial disparity and global temperature, and resilience across the K/T extinction event.

scholarly journals Optimal Design and Acoustic Assessment of Low-Vibration Rotor Blades

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
G. Bernardini ◽  
E. Piccione ◽  
A. Anobile ◽  
J. Serafini ◽  
M. Gennaretti
Keyword(s):  
Operating Conditions ◽  
Rotor Blades ◽  
Design Parameters ◽  
Blade Design ◽  
Genetic Optimization ◽  
Flow Conditions ◽  
Nonlinear Beam ◽  
Blade Shape ◽  
The Impact ◽  
Genetic Optimization Algorithm

An optimal procedure for the design of rotor blade that generates low vibratory hub loads in nonaxial flow conditions is presented and applied to a helicopter rotor in forward flight, a condition where vibrations and noise become severe. Blade shape and structural properties are the design parameters to be identified within a binary genetic optimization algorithm under aeroelastic stability constraint. The process exploits an aeroelastic solver that is based on a nonlinear, beam-like model, suited for the analysis of arbitrary curved-elastic-axis blades, with the introduction of a surrogate wake inflow model for the analysis of sectional aerodynamic loads. Numerical results are presented to demonstrate the capability of the proposed approach to identify low vibratory hub loads rotor blades as well as to assess the robustness of solution at off-design operating conditions. Further, the aeroacoustic assessment of the rotor configurations determined is carried out in order to examine the impact of low-vibration blade design on the emitted noise field.

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