Generalized Procrustes Analysis Research Articles

Morphology and growth of the pediatric lumbar vertebrae

BACKGROUND CONTEXTThe majority of existing literature describing pediatric lumbar vertebral morphology are limited to characterization of the vertebral bodies, pedicles, and spinal canal and no study has described the rates of growth for any lumbar vertebral structure. While it is known that growth of the lumbar vertebrae results in changes in vertebral shape, the dimension ratios used to quantify these shape changes do not represent the 3D morphology of the vertebral structures. Additionally, many of the previous evaluations of growth and shape are purely descriptive and do not investigate sexual dimorphism or variations across vertebral levels. PURPOSEThis study aims to establish a database of pediatric lumbar vertebra dimension, growth, and shape data for subjects between and ages of 1 and 19 years. STUDY DESIGNA retrospective study of computed tomography (CT) data. METHODSRetrospective, abdominal, CT scans of 102 skeletally normal pediatric subjects (54 males, 48 females) between the ages of 1 and 19 years were digitally reconstructed and manually segmented. Thirty surface landmark points (LMPs), 30 vertebral measurements, the centroid size, centroid location, and the local orientation were collected for each lumbar vertebra along with the centroid size of the LMPs comprising each subject's full lumbar spine and their intervertebral disc (IVD) heights. Nonparametric statistics were used to compare dimension values across vertebral levels and between sexes. Linear models with age as the independent variable were used to characterize dimension growth for each sex and vertebral level. Age-dependent quadratic equations were fit to LMP distributions resulting from a generalized Procrustes analysis (GPA) of the vertebrae and fixed effects models were used to investigate differences in model coefficients across levels and between sexes. RESULTSIntervertebral level dimension differences were observed across all vertebral structures in both sexes while pedicle widths and IVDs heights were the only measurements found to be sexually dimorphic. Dimension growth rates generally varied across vertebral levels and the growth rates of males were typically larger than those of females. Differences between male and female vertebral shapes were also found for all lumbar vertebral structures. CONCLUSIONSTo the authors’ knowledge, this is the first study to report growth rates for the majority of pediatric lumbar vertebral structures and the first to describe the 3D age-dependent shapes of the pediatric lumbar spine and vertebrae. In addition to providing a quantitative database, the dimension, growth, and shape data reported here would have applications in medical device design, surgical planning, surgical training, and biomechanical modeling.

Qualitative behavioural assessment of pain in castrated lambs

This study investigates for the first time the application of Qualitative Behavioural Assessment (QBA) to the analysis of acute pain expression in castrated lambs. Eighty 2-day-old male lambs were allocated to one of 4 groups (n = 20 per treatment): handled only (control, C), rubber ring castration (RR), short-scrotum castration (SSC) and rubber ring castration combined with Burdizzo (COM). Ethogram-based lamb behaviours and postures were recorded continuously from video for 30 min after application of castration rings or handling, and Kruskal-Wallis and Mann-Whitney tests were used to investigate differences between treatment groups. For QBA assessment a 2-minute video clip was extracted from the 30 min footage for each lamb, starting 15 min after treatment. Ten observers, blind to the castration treatment, provided QBA of the 80 clips, using Free Choice Profiling methodology. Data were analysed using Generalized Procrustes Analysis. Results show that for the 30 min. after castration or handling RR and SSC lambs had a higher frequency of active pain behaviour (RR = 110.5, SSC = 97.0, COM = 25.0, C = 24.0; p < 0.001) and restlessness (RR = 33.0, SSC = 22.0, COM = 10.0, C = 9.5; p < 0.001), than COM and C lambs. QBA identified two main dimensions of lamb expression: ‘calm/comfortable - restless/painful’ (44.8 % of variance), and ‘curious/active - tired/lethargic’ (35.8 %), with both dimensions showing significant effects of treatment (dimension1: F2,78 = 13.12, p = 0.001; dimension2: F2,78 = 24.26, p = 0.001). Post-hoc analysis showed RR lambs were perceived as significantly more restless/painful than COM, C and SSC lambs (T=-6.213, P = 0.001; T=-3.805, P = 0.001; T=-3.458, P = 0.005, respectively), and SSC lambs as more restless/painful than COM lambs (T = -2.8, P = 0.03) but not C lambs. In addition RR, COM, and SSC lambs were perceived as more tired/lethargic than C lambs (T=-7.535, P = 0.001; T=-7.01, P = 0.001; T=-5.904, P = 0.001, respectively). In sum, QBA was able to distinguish between four castration techniques through the characterisation of expressive lamb demeanour, with RR castration identified as the most painful of the tested methods. It also characterised COM lambs as more tired/lethargic than Control lambs, where quantitative behaviour measures discerned no difference between the two groups. QBA thus emerges as a promising indicator for the assessment of pain and welfare in castrated lambs.

Anatomical characterization of the inguinal lymph nodes using microcomputed tomography to inform radical inguinal lymph node dissections in penile cancer.

Radical inguinal lymph node dissections (rILND) for penile cancer risk significant postoperative lymphocele and lymphedema. However, reducing the risk of lymphatic complications is limited by our understanding of lymphatic anatomy. Therefore, this study aims to elucidate the lymphatic anatomy within the current surgical borders of a rILND. To visualize the position of the lymph nodes, tissue packets excised from the inguinal region of five fresh, male cadavers were imaged using microcomputed tomography (µCT). To standardize the position, rotation and size between specimens, each lymph node packet was aligned using a Generalized Procrustes analysis. There was a median of 13.5 lymph nodes (range = 8-18) per packet, with the majority (99%) clustered within a 6 cm radius of the saphenofemoral junction; a region 39%-41% smaller than current surgical borders. No difference existed between the number of nodes between sides, or distribution around the saphenofemoral junction. This study provides the first 3D, in situ, standardized characterization of lymph node anatomy in the inguinal region using µCT. By using knowledge of the normal lymphatic anatomy, this study can help inform the reduction in borders of rILND to limit disruption and ensure a complete lymphadenectomy.

Morphometric variation of the frontal bone in an adult South African cadaveric sample.

Recent developments in geometric morphometrics enabled reassessment of features of the cranium in a more robust, objective and quantitative manner. Previous studies show that morphological variation of not only the cranium as a whole, but also parts thereof are useful in differentiating between sex and population groups. The present study used geometric morphometrics to assess variation of frontal bone morphology and its use in estimation of sex and ancestry. Frontal bones of 777 Black, Coloured and White South African adults were digitized and superimposed through Generalized Procrustes Analysis. Centroid sizes and morphological variation between groups were assessed. Accuracy of distinction between groups was assessed using Discriminant Function Analysis and leave-one-out cross-validation. Male frontal bones were more robust and sloped, compared to more gracile, rounded frontal profiles of females, resulting in classification accuracy of 79.3%. Morphological variation related to ancestry was found in the slope and width of the frontal bones, allowing distinction of the groups with 85.9% accuracy, even when including the heterogeneous Coloured group. When assessed according to sex and ancestry combined, 83.3% accuracy was achieved with the six sex-ancestry groups. These results show that variation in frontal bone morphology is sufficient to allow accurate distinction between these closely related groups, with accuracies compatible or exceeding those obtained when using the entire cranium of the same sample. Future studies may be able to investigate similar use of morphological variation of other cranial bones for estimation of sex and/or ancestry for use when the cranium is damaged or fragmented.

Revisiting Guilt, Shame, and Remorse

We explored the observed similarity/dissimilarity among guilt, shame, and remorse (GSR) by conducting an empirical study in three phases—(i) generation of scenarios, (ii) development of illustrations and determination of item (scenario) equivalence, and (iii) rating of GSR induced by the scenarios. Ten young adults wrote their life experiences of guilt, shame and remorse, respectively, yielding a total of 34 scenarios. The scenarios were presented to 138 participants, and they were instructed to reflect upon the emotion (GSR) that best suited the scenarios. Principal component analysis indicated that the same scenario induced guilt as well as shame or remorse depending on the valence. Scenarios with positive factor load assessed guilt, whereas shame and remorse had negative factor load. Following an iterative process, the scenarios were converted into illustrations where each scenario was depicted in a storyboard comprising a set of three illustrations. Generalized procrustes analysis was performed to assess item equivalence between the narrations and the corresponding storyboards. Fourteen participants first rated the narratives and then the storyboards after a gap of 24 h. The findings suggest no significant difference between the illustrated scenarios and the narrative, thus leading to 13 scenarios. Multidimensional scaling suggests that the perception of shame and remorse overlaps and this is distinct from guilt.

Evaluation of shape and asymmetry in rye leaf

The variability of bilateral structures is associated with the stability of development; the populations attribute which characterizes homeostasis of plant development at the epigenetic level. A violation in the functioning of regulatory proteins creates a deviation from the norm in fluctuating asymmetry, as a measure of ontogenetic noise. To test the variability of the shape and asymmetry of winter rye leaf plates depending on the dose of mineral fertilizer, we used the Generalized Procrustes analysis and the thin splines method. A small dose (N90P90K90) caused the apical growth and the fluctuating asymmetry of the leaf plate, indicating a reduced development stability of the population (p <0.0001), the “side” factor was statistically insignificant. The interaction side × individual was statistically significant at both doses of fertilizer. The bending energy of the thin spline was higher (p = 0.001) in population with an increased dose of fertilizer (N90P90K90) and high directional asymmetry (“side”; p <0.0001). The authors consider that a high dose of fertilizer contributed to the synthesis of cells in the medial part of the leaf blade and caused asymmetry in a mix of fluctuating and directional asymmetry. Thus, an increased dose of mineral fertilizer enhanced the growth of the lateral part of the leaf blade and led to directional asymmetry, which reduced the asymmetric variability and increased the variability of the shape in the leaf blade.

Shape diversity of the fish genus Astyanax Baird &amp; Girard, 1854 (Teleostei, Characidae) in adjacent basins

The Neotropical region is highly diverse in fresh water teleost fishes and extends through vast regions of South America. The genus Astyanax comprises small fish found in the tributaries and ditches of the great Brazilian basins, such as the Parana and Sao Francisco Rivers. This group has been ostensibly studied from a chromosomal and molecular point of view but is still involved in problems of phylogenetic location, justifying its position incertae sedis, while having a wide diversity of forms and habitats. Our study counted on the analysis of body shape variations in seven species of the genus Astyanax and in the bimaculatus, fasciatus, and scabripinnis complexes using geometric morphometrics. We obtained images of individuals from different localities in the Parana and Sao Francisco River basins, delineated two-dimensional anatomical landmarks that we then subjected to the generalized Procrustes analysis, and subsequent ordination by principal component analysis and canonical variate analysis. The results showed variation between two large groups, related mainly to variations in body height, indicating the probable existence of different evolutionarily significant units morphologically shaped by the pressure of the environment with what may be incipient speciation.

The evolution of palate shape in the Lepilemur-Cheirogaleidae clade (Primates: Strepsirrhini).

Phylogenies consistently group the folivorous Lepilemur species with the small-bodied insectivorous-frugivorous cheirogaleids. Juvenile lepilemurs and adult cheirogaleids share allometries in most aspects of skull morphology, except the palate. We investigated potential influences on palate shape in these taxa and several outgroups using geometric morphometrics. Our sample included representatives of four extant strepsirrhine families, Cheirogaleidae (including Lepilemurinae), Lemuridae, Indriidae, and Galagidae, and one subfossil Megaladapis. Our dataset comprised 32 landmarks collected from 397 specimens representing 15 genera and 28 species, and was analyzed using generalized procrustes analyses and between group principal component analysis. We explored the influence of size, phylogeny, diet, and the propagation of loud vocalizations on palate shape. While congeneric species clustered within the morphospace, the phylomorphospace did not mirror molecular phylogenetic hypotheses of higher-order relationships. Four palate forms were distinguished within the Cheirogaleidae. Diet, strongly linked to body size, had the single greatest influence on palate shape. The production of long-distance advertisement calls was most often associated with positive scores on the PC1 axis. Our results suggest that the extensive variation in palate shape among Cheirogaleidae is related to dietary shifts that accompanied changes in body size during the clade's radiation. Molecular phylogenies indicate that cheirogaleid diversification involved repeated dwarfing events, which in turn drove dietary shifts from ancestral folivory-frugivory to frugivory, gummivory, and faunivory in the descendant species. The elongated Lepilemur palate is probably related to accelerated eruption of the cheek teeth to render juveniles competent to shear leaves upon weaning.

A computerized craniofacial reconstruction method for an unidentified skull based on statistical shape models

Craniofacial reconstruction (CFR) has been widely used to produce the facial appearance of an unidentified skull in the realm of forensic science. Many studies have indicated that the computerized CFR approach is fast, flexible, consistent and objective in comparison to the traditional manual CFR approach. This paper presents a computerized CFR system called CFRTools, which features a CFR method based on a statistical shape model (SSM) of living human head models. Given an unidentified skull, a geometrically-similar template skull is chosen as a template, and a non-registration method is used to improve the accuracy of the construction of dense corresponding vertices through the alignment of the template and the unidentified skull. Generalized Procrustes analysis (GPA) and principal component analysis (PCA) are carried out to construct the skull and face SSMs. The sex of the unidentified skull is then predicted based on skull SSM and centroid size, rather than geometric measurements based on anatomical landmarks. Furthermore, a craniofacial morphological relationship which is learnt from the principal component (PC) scores of the skull and face dataset is used to produce a possible reconstructed face. Finally, multiple possible reconstructed faces for the same skull can further be recreated based on adjusting the PC coefficients. The experimental results show that the average rate of sex classification is 97.14% and the reconstructed face of the unidentified skull can be produced. In addition, experts’ understanding and experience can be harnessed in production of face variations for the same skull, which can further be used as a reference for portraiture creation.

Asymmetries of Forelimb Digits of Young Cattle.

Based on the anatomical premise that, in bovines, the medial (inner) hoof is larger than the lateral (outer) one in the forelimb, we hypothesized that this implies a phalangeal form difference. To test this hypothesis, asymmetries of the forelimb acropodia (phalangeal series) were studied on calves belonging to the Brown Pyrenean breed, a meat breed managed under extensive conditions in NE Spain. Dorso-palmar radiographs were obtained for each acropodium in a sample of 17 paired left and right forelimbs. Size and shape were analysed by means of geometric morphometrics on medial and lateral acropodial series (III and IV series respectively) for each left and right limb. Shape coordinates were computed by Generalized Procrustes Analysis. Medial and lateral acropodial series appeared similar in size, but their shape expressed an especially high directional asymmetry, with distal phalanges (pedal bones) being abaxially (outwards) oriented. Such morphological observations may be an important reconsideration of “normal” radiographic acropodial symmetry evaluation. This can be explained not only by an unevenly distributed ground reaction force between acropodial series, but also between right and left limbs, making medial and lateral hoof surfaces differently prone to overloading and, accordingly, to injuries to the limb.

Making Heads or Tails of Combined Landmark Configurations in Geometric Morphometric Data

Researchers using geometric morphometric methods can be confronted with a need to combine separate landmark configurations from the same research subjects as a more holistic description of organismal morphology. Combining configurations might be valid if single configurations represent separate anatomical structures that can change position with respect to each other or have been shown to be phenotypically integrated, and researchers would prefer to recognize these structures as one set, rather than multiple sets. However, generalized Procrustes analysis (GPA) scales separate configurations to unit size, meaning that in combination, some attempt to relativize the size of configurations should be made. A few recent studies have calculated the relative size of separate configurations in different ways but there has been no formal consideration for the implications of a priori judgments for how configuration sizes should be weighted, before the synthesis presented here. We offer a general solution for weighting separate configuration centroid sizes when combining them, which captures the intention of different methods thus far proposed. We also demonstrate that under various conditions, weighting via normalized centroid size is fraught with problems, and should be avoided. By contrast, an unweighted approach that seeks to maintain landmark densities in separate configurations provides reliable results. Nevertheless, researchers should realize that combining configurations creates new configurations with landmark covariances that are arbitrary with respect to any real anatomical features. As such, combining landmark configurations should not be a haphazard enterprise under any circumstances.

Statistical shape analysis of corpus callosum in restless leg syndrome

ABSTRACT Objectives In this study we aimed to investigate corpus callosum shape differences between restless leg syndrome patients and healthy controls, and to determine whether disease severity and duration are indicators for corpus callosum deformation in RLS patients. Methods This study was conducted using the magnetic resonance imaging scans of 33 restless leg syndrome patients and 33 control subjects. Landmarks were marked on the digital images and callosal landmark coordinate data were used to assess shape difference by performing Generalized Procrustes analysis. The shape deformation from controls to the patients was evaluated performing the Thin Plate Spline approach. Results There was a statistically significant shape difference between the groups. Highest deformation was determined at the posterior midbody of the corpus callosum. Growth curve analyses showed that with the increase in disease duration and severity, the CC size decreased. Discussion The present study demonstrated callosal shape differences in restless leg syndrome using a landmark-based geometric morphometric approach, considering the topographic distribution of corpus callosum for the first time.

Comparison of the Flash Profile and the Napping®-UFP Techniques in the sensory characterization of hot-dog

The similarity between the Flash Profile and the Napping®-Ultra Flash Profile (Napping®-UFP) techniques was evaluated using the vector correlation coefficient (Rv). For this purpose, two commercial hot-dog brands from the Lima market and two formulations obtained by Kansei Engineering were sensory characterized. In the Flash Profile, consumers generated and rated their own descriptors, which were processed using the generalized Procrustes analysis. In Napping®-UFP, consumers positioned and described the hot-dog samples on an A3 size sheet. The coordinates (x, y) of each sample and the descriptive terms were processed by multiple factor analysis. The consensus index (Rc = 61.2 %) and the overlap of the confidence ellipses in samples HD2.1 and HD2.2 showed that they did not have a significant sensory difference (p-value < 0.05). Finally, the Rv value (0.93) determined a high similarity between both sensory techniques.

How does co-registration affect geomorphic change estimates in multi-temporal surveys?

ABSTRACT High-Resolution Topography (HRT) data sets are becoming increasingly available, improving our ability and opportunities to monitor geomorphic changes through multi-temporal Digital Terrain Models (DTMs). The use of repeated topographic surveys enables inferring the sediment dynamics of hazardous geomorphic processes such as floods, debris flows, and landslides, and allows us to derive important information on the risks often associated with these processes. The topographic surveying platforms, georeferencing systems, and processing tools have seen important developments in the last two decades, in particular Light Detection And Ranging (LiDAR) technology used in Airborne Laser Scanning (ALS) and Terrestrial Laser Scanning (TLS). Moreover, HRT data, produced through these techniques, changed a lot in terms of point cloud density, accuracy and precision over time. Therefore, old “legacy” data sets and recent surveys can often show comparison problems, especially when multi-temporal data are not homogeneous in terms of quality and uncertainties. In this context, data co-registration should be used to guarantee the coherence among multi-temporal surveys, minimizing, on stable areas, the distance between corresponding points acquired at different epochs. Although several studies highlight that this process is fundamental to properly compare multi-temporal DTMs, it is often not addressed in LiDAR post-processing workflows. In this paper we focus on the alignment of multi-temporal surveys in a topographically complex and rugged environment as the Moscardo debris-flow catchment (Eastern Italian Alps), testing various co-registration methods to align multi-temporal ALS point clouds (i.e. years 2003, 2009 and 2013) and the derived DTMs. In particular, we tested the pairwise registration with manual correspondences, the Iterative Closest Point (ICP) algorithm and a mathematical model that allows aligning simultaneously a generic number of point clouds, the so-called Generalized Procrustes Analysis (GPA), also in its GPA-ICP variant. Then, to correct the possible small inaccuracies generated from the gridding interpolation process, a custom-developed DTM co-registration tool (GRD-CoReg) was used to align gridded data. Both alignment phases (i.e. at point cloud and DTM level) proved to be fundamental and allowed us to obtain proper and reliable DTMs of Difference (DoDs), useful to quantify the debris mobilized and to detect the spatial and temporal patterns of catchment-scale erosion and deposition. The consistency of DoDs data was verified through the comparison between the erosion estimate of DoDs and the volumes of debris-flow events measured by the monitoring station close to the Moscardo torrent catchment outlet. The GPA-ICP algorithm followed by the GRD-CoReg tool proved to be the most effective solution for improving DoDs results with a decrease of systematic trend due to vertical and horizontal uncertainties between surveys, especially at steep slopes. The net volume difference (i.e. the sediment output from the catchment) of the 2003–2013 period changed from 3,237,896 m3 to 135,902 m3 in DoDs obtained from not co-registered and co-registered DTMs. The volume of debris flows measured at the catchment outlet during the same time interval amounts to 169,660 m3. The comparison with debris-flow volume measures at the monitoring station shows, therefore, that the DTMs obtained from the co-registration processes generate more reliable DoDs than those obtained from the raw DTMs (without the alignment).

The brachiopod genus Composita in the Carboniferous successions from Rod El-Hamal area, Wadi Araba, north Eastern Desert, Egypt: A revision based on morphometric analysis

ABSTRACT This study provides quantitative and qualitative analyses for the brachiopod shells of the Genus Composita. For this study, 75 brachiopod specimens were collected from the Late Carboniferous Rod El-Hamal Formation that are exposed at Rod El-Hamal area, Wadi Araba, north Eastern Desert, Egypt. The collected brachiopod specimens belong to six species in genus Composita; Composita subtilita, C. subquadrata, C. ovata, C. ambigua, C. trilobata, and C. trinuclea. In order to distinguish the different species of Composita, morphometric analysis, using ImageJ and MorphoJ software packages, was applied. Morphometric analysis included landmark configurations, generalised procrustes analysis, principle component analysis, and thin-plate spline visualisation plots. In the Composita genus, the quantitative analysis proposed considerable variations along the posterior region.

Applied anatomic and phylogenetic considerations of surgical and regional nerve block landmarks on the skull and mandibles of two hystricomorphs; the crested porcupine (Hystrix cristata) and greater cane rat (Thryonomys swinderianus)

This investigation seeks to discriminate variations in anatomic landmarks of regional nerve block/surgical importance in skulls of two phylogenetically related laboratory species; the Old-world porcupines (H. cristata) and Cane rat (T. swinderianus), and comparedfrontal sinus shape outline architecture in mid-sagittal section for both. Using Generalized Procrustes Analysis, the study utilized thirty-seven and forty-eight skull samples of each respectively. for landmarks assessments in right lateral, ventral and right lateral hemi-mandibular views, and Elliptical Fourier analyses for frontal sinus contours. Extremely significant (P ≤ 0.0001) interspecies landmark size variations were observed with Mahalanobis distance of 1.89, 2.03 and 2.06 for the evaluated positions respectively, mean centroid size ranged from 3200 mm in H. cristata to 1400 in T. swinderianus. Shape regression model suggested similar allometric pattern except in mandibles (λ Wilks 0.96, F 44.55) but (λ Wilks 0.88, F 127.9) between species. EFA descriptors demonstrated. amplitude associated attenuations in harmonic values (factor about 1/8 to 1/22,000) with angular orientation in major axes values reduced by not more than ¼ after size normalization. PC1 & 2 contributed 81.19%, 6.29% but 100% in within and between species analysis. Stepwise harmonic increments outline reconstructions demonstrated disparities up to the 6th harmonics with marginally lower variance value in cane rats (1.37) than in porcupines (1.68). The results conclude that skull shape and size disparities observed suggest despite similar phylogeny both are diverse and does not compare in structural and frontal sinus outline shapes.

Facial Asymmetry Increases as a Function of Age

Humans, like all bilaterian organisms, follow a symmetric body plan during growth and development. Deviations from symmetry during growth arise as a function of developmental instability caused by biological and environmental stressors such as poor diet and illness. Fluctuating asymmetry (FA) refers to random left/right asymmetries and is considered a quantifiable proxy for developmental stress. This study will investigate the patterning of facial asymmetry in a large population to highlight aspects of facial asymmetry within and between age groups. We also quantify FA across the sample to test the hypothesis that facial asymmetry increases as a function of age.To determine whether levels of facial asymmetry vary with age, a cross‐sectional sample of n=900 facial scans representing four age groups (child: 3–10 y/o, adolescent: 11–18 y/o, young adult: 19–27 y/o, and older adult: 28–40 y/o) from the University of Pittsburgh Center for Craniofacial and Dental Genetics 3D Facial Norms study were analyzed. 34 landmarks were captured along facial structures including the eyes, nose, mouth, and chin, superimposed using Generalized Procrustes Analysis (GPA), and analyzed using geometric morphometrics (GM) in MorphoJ. Following GPA, the asymmetric component of facial shape was examined using both Principal Components Analysis (PCA) and Canonical Variate Analysis (CVA) to evaluate patterns of overall facial asymmetry and whether or not different facial asymmetry patterns exist between age groups. Finally, a Procrustes ANOVA was employed to calculate a fluctuating asymmetry (FA) score for each individual and scores were regressed against age to test whether facial asymmetry increases with age.PCA results identified 43 principal components (PCs), of which the first three components accounted for nearly 42% of the overall facial asymmetric shape variation. PC1 confirmed that 19.7% of the asymmetries occurred in eye position, accounting for the largest aspect of facial asymmetry in the combined sample. PC2 and PC3, accounting for 12.8% and 9.4% of the asymmetric shape variation respectively, occurred mostly in the lower face and jaw line. Results from CVA found significant differences (p&lt;0.02) in facial asymmetry between the age groups. CV1, accounting for 84% of the variation between groups identified asymmetries predominantly in the eyes and nose. CV2 (11.7% variation) demonstrated asymmetries of chin and lower face while CV3 (4.3%) indicated variations in asymmetry of the jaw line. Lastly, results from the Procrustes ANOVA confirmed a significant positive relationship between age and fluctuating asymmetry (p=0.0002, r2=0.014).This study identifies key aspects of facial asymmetry that exist between younger and older age groups, particularly increased asymmetries in the lower face of the adult groups compared to the younger age groups. Additionally, fluctuating asymmetry does increase slightly as a function of age, confirming our hypothesis. Future research will focus on specific factors that relate to these facial asymmetries, such as poor diet, using both cross‐sectional and longitudinal populations.Support or Funding InformationR01‐DE016148

A Comparison of Spherical Harmonic and Sliding Semilandmark Analyses as Methods for Three‐Dimensional Shape Evaluation

The ability to quantify morphological variation is integral to biological research. The use of sliding semilandmarks in geometric morphometric (GM) analyses allows for the evaluation of whole bone morphology in three dimensions. A sliding semilandmark analysis, however, is difficult to complete when structures lack obvious homologous features for landmark placement. Spherical harmonics (SPHARM) offers an alternative method for shape analysis in such cases. Here we evaluate the SPHARM method by comparing results to those from a sliding semilandmark analysis of the calcaneus in African apes and modern humans.Modern human (n=20), chimpanzee (n=20), and gorilla (n=20) calcanei were surface scanned. For the GM analysis, 1007 sliding semilandmarks were evenly distributed across the external surface of each calcaneus. Semilandmarks were slid to minimize the bending energy of the thin plate spline interpolation function relative to an updated Procrustes average. Final landmark configurations were then aligned using Generalized Procrustes Analysis. For the SPHARM analysis, surface models were mapped onto the surface of a sphere (parameterization), and then decomposed into a weighted sum of spherical harmonic functions. Because the spherical harmonics provide a standardized basis for quantifying shape, coefficients of the harmonic functions can be used as shape descriptors. Calcaneal shape variation was summarized using a principal components (PC) analysis of the Procrustes coordinates and SPHARM coefficients. Analyses were compared through calculation of the root mean square (RMS) and maximum distance between surface models of the average specimen from each species, as well as surface models of PC warps created two standard deviations from the average along PCs 1–3.Both sliding semilandmark and SPHARM analyses separate species along the first two PCs. For both analyses, African apes and modern humans separate along PC1. Average RMS between species averages was 0.25 mm. Maximum surface distances between average surface models from the two analyses were all less than 0.23 mm. Average RMS between all respective PC warps was 0.82 mm. Maximum surface distances between PC warps were all less than 1 mm. Although there were minor differences between PC plots produced from the two analyses, the same general morphological distinctions between species were identified. The primary differences between SPHARM and sliding semilandmark‐based surface models of PC warps and species averages occur around sharp edges, which are less defined using the SPHARM analysis, although these differences are small. Overall, SPHARM provides the same shape representation as a sliding semilandmark analysis, making it a comparable method for the evaluation of shape in three dimensions.Support or Funding InformationThis project was supported by NSF grant # BCS ‐ 1824630.

Variants in the Hippo Signaling Pathway are Associated with Craniofacial Skeletal Form and BMI

Childhood obesity rates in the United States have demonstrated a marked increase since the late 20th century. Current research has suggested that obesity can cause increases in bone density and an acceleration of skeletal growth. While studies have shown that obesity may be associated with altered craniofacial form, the mechanism and associated factors through which this interaction operates remains poorly understood. This study explores a potential link between obesity and craniofacial skeletal form as a function of the Hippo signaling pathway, an important regulator of organ size, tissue development, and craniofacial development.Lateral cephalograms from a sample of n=64 patients between the ages 7 to 17 were obtained from the Midwestern University Multispecialty Clinic. BMI percentile was computed for all children in the study following CDC guidelines (normal weight n=37, overweight n=9, obese n=18). 45 2D landmarks were registered via Generalized Procrustes Analysis (GPA) in order to facilitate a geometric morphometric (GM) analysis. Healthy Eating Index (HEI) scores obtained from Block Food Frequency Questionnaire (FFQ) surveys were used to control for the effects of diet in all subsequent analyses. Shape residuals were submitted to Principal Components Analysis (PCA) and Canonical Variate Analysis (CVA) to identify which aspects of skeletal form differentiate individual phenotypes based on BMI. Finally, associations between these phenotypes and 23 single nucleotide polymorphisms (SNPs) in seven genes within the Hippo signaling pathway were explored.Principal Components (PCs) accounting for at least 1% of facial shape variation were examined in order to determine components that differentiate between normal and obese groups. Based on this, suggestive/significant differences were found in PC 8 (p=0.056) and PC12 (p=0.012) based on BMI category. PC 8 (accounting for 3.6% of the total shape variation) indicates that chin projection, nose length, and mandibular morphology differentiate between normal and obese children. SNPs in TEAD3 (p=0.04) and FAT4 (p = 0.02) were significantly associated with shape variation along PC8. PC 12 (2.6% of the total shape variation) showed significant variation in chin projection and decreased incisor size in the obese group relative to the normal weight group. Additionally, a SNP within LATS2 (p = 0.04) was significantly correlated with shape variation along PC12. Finally, results from the CVA identified two components with CV2 indicating a significant relationship with LEF1 (p= 0.02). CV2 demonstrates increased facial projection in individuals with obesity.Across all analyses, we found a consistent pattern in mandibular length, facial projection, and incisor size that differentiated between normal and obese individuals. SNPs within key genes in the Hippo signaling pathway were associated with these phenotypes, indicating a potential causative relationship. Future studies will explore this relationship further.

Human calcaneal external shape relative to activity and foraging levels

The role of the calcaneus in weight‐bearing suggests that it may reflect differences in activity and foraging levels among different modern human populations. While lower limb cortical and trabecular bone have been demonstrated to vary with regard to human behavior, human calcaneal variation has not been studied in this context. Here we analyze the entire calcaneal external shape of recent industrialized modern humans (n=60), Native American agriculturalists (n=47), a transitional Native American population that had not fully adopted agriculture (n=10), and Late Stone Age Khoesan hunter‐gatherers (n=13).Calcanei were either surface or micro‐CT scanned and their external shape analyzed using a three‐dimensional geometric morphometric sliding semilandmark analysis. Semilandmarks were allowed to slide relative to an updated Procrustes average to minimize the bending energy of the thin plate spline interpolation function. Final landmark configurations were aligned using a Generalized Procrustes Analysis. Shape variation was summarized using a principal components analysis. Procrustes distances between different human populations were calculated, and resampling statistics run to test for significant differences.All human populations demonstrate statistically different calcaneal morphologies (p&lt;0.005 for all comparisons). Industrialized and non‐industrialized populations separate from each other across the first six principal components (52.34% of variance). Non‐industrialized populations demonstrate a mediolaterally wider and superoinferiorly taller posterior calcaneus and tuber, as well as a larger peroneal trochlea. This greater robusticity is likely adapted for the increased load through the calcaneus associated with a non‐sedentary lifestyle. The industrialized sedentary modern humans, however, possess a relatively larger lateral plantar process, potentially as a compensatory mechanism for bipedal behaviors in a generally less robust and more antero‐posteriorly elongate calcaneus.Support or Funding InformationThis project was supported by NSF grant # BCS ‐ 1824630.