Cross-sectional Geometric Properties Research Articles

Mechanical stress in the urbanized Roman Phoenician coast

ObjectiveSkeletal populations from Byblos, Beirut, and Tyre were studied to assess mechanical stress along the Roman Phoenician coast. MaterialsThe sample included 153 adult skeletons. MethodsSkeletal remains were macroscopically assessed for osteoarthritis, intervertebral disc disease (IDD), and Schmorl’s nodes. ResultsThe Byblos population experienced higher levels of mechanical stress than the Beirut and Tyre ones. Sex-based differences were also found in all skeletal assemblages with males likely engaging in physically more demanding tasks. ConclusionsThe variation in mechanical stress, and associated physically demanding tasks, between these populations can be attributed to their differing political and economic status during the Roman period; textual sources highlight the economic and political dominance of Beirut and Tyre, emanating from their status as coloniae. SignificanceThis study represents one of the first attempts to investigate mechanical stress in coastal Phoenicia during the Roman period. It provides valuable insights into the biocultural structure of understudied communities at the periphery of the Roman world, and can serve as a basis for further future research into the occupational patterns of Phoenician communities. LimitationsThe contextual information for these skeletal populations is very limited and does not allow secure conclusions regarding their representativeness. The sample sizes are also rather small, especially when divided per sex and age. Suggestions for Further ResearchFurther investigation employing complementary methods such as cross-sectional geometric properties and entheseal changes is needed to reconstruct the occupational patterns of these communities, taking into account cultural, environmental, and temporal factors.

Analytical model for axially compressed circular concrete-filled double skin steel tubes (CFDSTs): Insights from concrete non-uniformly confined states

Concrete-filled double skin steel tube (CFDST) is becoming a competitive structural concept in deep-sea and deep-ground engineering structures. However, the passive non-uniform confinement of the sandwiched concrete needs to be further clarified and quantitatively described to achieve better design efficiency of CFDSTs in sophisticated application scenarios. This investigation suggests a development approach for the analytical model of the axially compressed circular CFDSTs considering the non-uniform confinement effect. The strength and deformation characteristics of the concrete subjected to constant lateral stresses have been first systematically analyzed through the extensively collected experimental database, and the corresponding constitutive models have been formulated accordingly. The stress distributions of the sandwiched concrete and the influence of the cross-sectional geometric properties have been discussed, and then the calculation method for the non-uniform confining factor has been developed. An efficient analytical model has been established on the basis of an incremental-iterative procedure, with the steel tube-concrete interaction and bonding behavior appropriately considered. The proposed analytical model has been verified through the widely collected experimental data of axially compressed CFDSTs, and the results show that it could effectively simulate the full-range axial load–strain curves and improve the prediction accuracy of ultimate loads by about 5% to 16% compared with the existing design formulas.

Hierarchical multi-scale analysis of the effect of varying fiber bundle geometric properties on the mechanical properties of 3D braided composites

A hierarchical multi-scale numerical model is developed to predict the effect of cross-sectional geometric properties on the mechanical response of three-dimensional (3D) braided composites. In this model, the effective properties are transferred from the fiber bundle scale to the mesoscale, and the finite element and analytical methods are used to predict the macroscopic mechanical properties. Damage evolution was evaluated, based on a continuous damage mechanics approach. A user-defined material subroutine (UMAT), in a nonlinear finite element analysis, has been developed to implement the proposed model and further determine the response and subsequent damage evolution in 3D braided composites subjected to quasi-static tension. The elastic properties of the composites are predicted using a hybrid multi-scale model. The agreement between the numerical simulations and the experimental results is good. It has been shown that the cross-sectional geometry of the fiber bundle properties has a significant influence on the tensile behavior of the composite, which is captured by the proposed multi-scale damage model. This research offers a theoretical analysis for selecting the optimized fiber bundle geometry for using in FE predictions of 3D braided composites.

Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours.

Primate fingers are typically in direct contact with the environment during both locomotion and manipulation, and aspects of external phalangeal morphology are known to reflect differences in hand use. Since bone is a living tissue that can adapt in response to loading through life, the internal bone architecture of the manual phalanges should also reflect differences in manual behaviours. Here, we use the R package Morphomap to analyse high-resolution microCT scans of hominid proximal phalanges of digits 2-5 to determine whether cortical bone structure reflects variation in manual behaviours between bipedal (Homo), knuckle-walking (Gorilla, Pan) and suspensory (Pongo) taxa. We test the hypothesis that relative cortical bone distribution patterns and cross-sectional geometric properties will differ both among extant great apes and across the four digits due to locomotor and postural differences. Results indicate that cortical bone structure reflects the varied hand postures employed by each taxon. The phalangeal cortices of Pongo are significantly thinner and have weaker cross-sectional properties relative to the African apes, yet thick cortical bone under their flexor sheath ridges corresponds with predicted loading during flexed finger grips. Knuckle-walking African apes have even thicker cortical bone under the flexor sheath ridges, as well as in the region proximal to the trochlea, but Pan also has thicker diaphyseal cortices than Gorilla. Humans display a distinct pattern of distodorsal thickening, as well as relatively thin cortices, which may reflect the lack of phalangeal curvature combined with frequent use of flexed fingered hand grips during manipulation. Within each taxon, digits 2-5 have a similar cortical distribution in Pongo, Gorilla and, unexpectedly, Homo, which suggest similar loading of all fingers during habitual locomotion or hand use. In Pan, however, cortical thickness differs between the fingers, potentially reflecting differential loading during knuckle-walking. Inter- and intra-generic variation in phalangeal cortical bone structure reflects differences in manual behaviours, offering a comparative framework for reconstructing hand use in fossil hominins.

Cross-sectional properties of rib geometry from an adult population.

Introduction: Human body models (HBMs) play a key role in improving modern vehicle safety systems to protect broad populations. However, their geometry is commonly derived from single individuals chosen to meet global anthropometric targets, thus their internal anatomy may not fully represent the HBM's target demographic. Past studies show sixth rib cross-sectional geometry differences between HBM ribs and population-derived ribs, and corrections to HBM ribs based on these data have improved HBM's abilities to predict rib fracture locations. Methods: We measure and report average and standard deviations (SDs) in rib cross-sectional geometric properties derived from live subject CT scans of 240 adults aged 18-90. Male and female results are given as functions of rib number and rib lengthwise position for ribs 2 through 11. Population means/SDs are reported for measures of rib total area, rib cortical bone area, and rib endosteal area, as well as inertial moment properties of these rib sections. These population corridors are compared between males and females, and against the baseline rib geometries defined in six current HBMs. Results: Total cross-sectional area results found average males ribs to be larger than those of females by between approximately 1-2 SDs depending on rib number and position, and larger in cortical bone cross-sectional area by between 0-1 SDs. Inertial moment ratios showed female ribs being between approximately 0-1 SDs more elongated than male ribs, dependent again on rib number and position. Rib cross-sectional areas from 5 of the 6 HBMs were found to be overly large along substantial portions of most ribs when compared to average population corridors. Similarly, rib aspect ratios in HBMs deviated from average population data by up to 3 SDs in regions towards sternal rib ends. Discussion: Overall, while most HBMs capture overall trends such as reductions in cross-section along shaft lengths, many also exhibit local variation that deviates from population trends. This study's results provide the first reference values for assessing the cross-sectional geometry of human ribs across a wide range of rib levels. Results also further provide clear guidelines to improve rib geometry definitions present in current HBMs in order to better represent their target demographic.

Adapting in the Arctic II: Upper limb diaphyseal robusticity and habitual activity in Late Holocene hunter-gatherers from Alaska.

This study compares humeral diaphyseal robusticity and asymmetry between Late Holocene hunter-gatherers from Alaska with the goal of reconstructing habitual activity in relation to culture and environment. Ancestral remains from four geographic regions of Alaska were divided into five site groups defined by subsistence strategies and technology: Aleutian Islands, Coastal Bay, Far North Coastal, Inland/Riverine, and Tikeraq. Mid-distal humeral diaphyseal robusticity was quantified using cross-sectional geometric properties standardized by estimated body mass and bone length. Humeral strength and bilateral asymmetry were greatest in Aleutian Island males, moderate in Far North Coastal and Tikeraq males, and reduced in Inland/Riverine males. Left-biased directional asymmetry and reduced humeral strength were found in Coastal Bay males. Aleutian Island males had relatively mediolaterally strengthened humeri compared with other groups. Aleutian Island females had elevated humeral strength, while humeral asymmetry among females was moderate and did not vary between groups. Humeri were relatively round among Aleutian Island and Tikeraq females and anteroposteriorly (A-P) strengthened among Coastal Bay, Far North Coastal, and Inland/Riverine females. These results suggest elevated humeral strength and asymmetry in males that engaged in rowing and unimanual projectile hunting, while reduced humeral strength and asymmetry may reflect bow-and-arrow or ensnarement technologies. Left-biased humeral asymmetry may be associated with net-fishing. Humeral strength and asymmetry are consistent with select instances of unimanual projectile hunting in females, while differences in humeral A-P/mediolateral strength may reflect variation in butchery and processing of prey versus rowing and throwing behaviors.

Paving new ways in forensic contexts with virtual osteology applications: csg-toolkit – a 3D osteology package for cross-sectional geometry analysis

This work presents the newly updated csg-toolkit package for GNU Octave, a user-friendly virtual osteology software that can compute and visualize the diaphyseal cross-sectional geometric (CSG) properties of the long bones of the lower and upper limbs. The CSG properties of the diaphysis have been extensively used for mechanical loading studies and have recently shown promising results in research topics of forensic anthropology, such as skeletal activity markers, sex estimation, and osteometric sorting. The csg-toolkit optimizes the computation of the CSG properties by integrating existing 3D technologies and novel computational geometry methods in osteology, so that they can be embedded in forensic applications. This new version supports a number of additional options regarding the computation and visualization of those properties, such as placement customization for the cross-sections, automatic registration and identification of the specific bone model and its alignment points, and visual inspection of the cross-sections upon generation. Additional improvements have been made that minimize the effort and time needed for analyzing a long bone. The csg-toolkit is a reliable alternative to the traditional Latex Cast Method. Overall, the csg-toolkit provides a simple, flexible, and computationally accurate method for 3D virtual long bone analysis and its free and open-source implementation can facilitate the utilization of cross-sectional geometry in forensic contexts.

Lower limb bone structure of Middle Pleistocene hominins from the Caune de l’Arago (Tautavel, France): Evolutionary and functional comparison with the penecontemporaneous hominins of Sima de los Huesos (Atapuerca, Spain)

The Caune de l’Arago (Arago) and Sima de los Huesos (Sima) human bones from the European Middle Pleistocene are penecontemporaneous, although the Sima hominins are closely related to Neandertal, and Arago hominins present more archaic features. In previous and in press studies, the cross-sectional geometric properties (CSG) of lower limb bones of Arago and Sima have been studied separately without comparative analyses. Here, in order to bridge this gap, we use the same criteria for both samples to highlight evolutionary affinities and to compare their level and pattern of mobility. This study focuses on the femur, fibula and tibia from Arago and Sima with references to fossils from the sites of Trinil, Zhoukoudian and Lazaret, and ancient and recent Homo sapiens (including athletes and non-athletes). We analyze the cross-sectional areas, biomechanical bone “shape” indices (Ix/Iy, Imax/Imin) and pattern of cortical bone distribution. All lower limb bones from Arago have noticeably high to very high relative cortical areas and low to very low medullary areas. The overall femoral pattern in Arago, like Sima, is similar to that of Middle Pleistocene hominins (e.g., low femoral shape indices, Ix/Iy) and Neandertals (e.g., large cross-sectional size). However, the femoral midshaft in Sima presents prominent posteromedial cortical thickening, as a result of a spiral cortical reinforcement along the medial side of the diaphysis. This characteristic is specific to Neandertal and some Middle Pleistocene hominins. In contrast, the midshaft femoral pattern in Arago is close to that of some Homo erectus. We also note that the femoral cross-sectional size and relative cortical area in Arago differ drastically to the small size and low relative cortical area of Lazaret and Trinil hominins. The very high shape index at midshaft (i.e., high Imax/Imin) of the Arago tibia is observed in ancient H. sapiens and runners; the tibial posterior “pilaster” is found in Neandertals and ancient H. sapiens; and the flat or convex tibial faces are similar to Neandertals. Furthermore, the Arago fibulas show marked fibular posterolateral cortical reinforcement with low anteroposterior strengthening. These leg features (tibia, fibula) are also found in some Sima hominins (but not in all individuals). Consequently, this study confirms the presence of archaic features in Arago and the close evolutionary relationship between Sima and Neandertal. This proposition is mainly based on the femoral midshaft pattern influenced by the pelvofemoral complex, considered to be substantially genetically controlled. The leg functional analysis highlights a high level of mobility and travelling in uneven terrains or in mountainous areas in Arago, consistent with known environments and hunting practices. Previously, an analogous hypothesis was proposed put forward for Sima hominins.

Appositional long bone growth: Implications for measuring cross‐sectional geometry

AbstractObjectivesAs growth at the periosteal and endosteal surfaces varies with age, cross‐sectional geometric (CSG) properties derived from periosteal (“solid”) contours may not produce comparable results to those from endosteal and periosteal contours (“true”), contrary to findings from adults. Error in CSG properties derived from the “solid” sections is compared with “true” sections in a sample of archeologically derived skeletons with estimated dental ages ranging from 1.5 months to 23.5 years.Materials and MethodsCross sections were extracted from 3D surface models, and endosteal contours were located from biplanar radiographs for 56 femora and 59 humeri. Polar second moment of area (J), cross‐sectional shape (Imax/Imin), and polar section modulus (Zp) were calculated from solid and true sections. Relationships between solid and true properties were examined with least squares regression. Multiple regression examined the effect of age and % cortical area on solid section CSG error.ResultsWhile correlations were high (R2 = 0.72–0.99, all p < 0.001), the results indicate that solid CSG properties are not within an acceptable error range (%SEE of ≤8.0, and %PE of ≤5.0) of true CSG. Error was most affected by %CA, while estimated age was not correlated with %CA, %PE, or percent difference of true‐solid CSG.DiscussionPeriosteal contours alone should not be used to calculate CSG properties from individuals during the period of growth and development. Variation in bone growth and/or adaptive responses independent of age may account for the inconsistent age effects.

Reliability-Based Assessment of Galloping Instability of Thin-Walled Steel Beams

Abstract Galloping instability relating to cross-wind vibrations can be found in flexible and lightly damped structures. In the present paper, the reliability of a thin-walled steel beam in maintaining its galloping stability was examined using a probabilistic approach. The analysis considered random variation in the cross-sectional geometrical properties of the beam, the material elastic modulus, the structural damping and the wind speed. A large number of Monte Carlo simulations were performed with normal and Gumbel distributions applied to the random variables to determine the probability distribution function of the safety margin. The limit state is considered violated when the wind speed exceeds the onset wind velocity of galloping, resulting in the aerodynamic damping being greater than the structural damping. It was shown by a conventional codified safety factor method that the beam was robust enough for galloping stability. By contrast, the probability-based assessment revealed that the beam failed to achieve the target reliability index in case the coefficient of variation of wind speed was greater than 5%. The analysis results suggested that the code-satisfied slenderness of the beam should be reduced by a factor of 1.5-1.7 under the action of wind speed with a coefficient of variation in the range 30-40%.

Dynamic analysis of RC beams externally bonded with FRP plates using state space method

The state space method is used to investigate the in-plane linear dynamic behavior of reinforced concrete (RC) beams externally bonded with fiber-reinforced polymer (FRP) plates. The state space formulae are properly set up by selecting the appropriate generalized displacements and their conjugated forces as state variables. By adopting the numerically stable method to solve the homogeneous state equations with respect to the mode function vectors, the frequencies and corresponding modal shapes for the free vibration of the FRP-strengthened RC beams under generalized boundary conditions are subsequently obtained. The orthogonality of the vibration modes is established based on the concept of symplectic inner product. By utilizing the modal superposition method, the analytical solutions of the inhomogeneous governing equations for forced vibration and the dynamic responses of the FRP-strengthened RC beams subjected to a uniformly distributed step load, concentrated triangular impulse load at the mid-span, moving concentrated load, and vertical seismic load are obtained. Finally, several numerical examples are presented to validate the results against those obtained by the general-purpose finite element software ABAQUS. Good agreement between the results is observed. Moreover, parametric studies are conducted to investigate the effects of the cross-sectional geometric and material properties of the FRP plate and adhesive layer on the peak interfacial shear stress at the plate end when the strengthened beam is subjected to a uniformly distributed step load or a moving concentrated load.

Evolution and biomechanical variation in mammalian ungual phalanges with respect to locomotion

Past studies of the morphology of the claw-bearing phalanges among mammalian taxa has revealed a correspondence of ungual phalanx shape and the broad form of locomotor behavior carried out by those taxa. Further research has provided evidence for convergence in the morphology of ungual phalanges among distantly related taxa that engage in similar locomotion. This evolutionary parallelism is proposed to have been motivated by conserved, shared morphogenic pathways. Such evidence would argue that, despite phylogenetic divergence, we would expect to observe: 1) similar biomechanical properties in ungual cross-sectional geometry among unrelated taxa performing similar forms of locomotion; and 2) phylogenetic modeling of the evolution of ungual phalanx morphology should demonstrate evidence for selection and convergence. In this study, we test these hypotheses using linear dimensions and cross-sectional geometric properties (CGSP) obtained from 42 mammalian taxa. This sample represents a breadth of taxa that have previously been classified into five broad locomotor guilds (arboreal, cursorial, fossorial, generalist, scansorial). CSGP (Ix, Iy, J) were obtained using a Stratec pQCT scanner, and linear dimensions of the phalangeal length, mid-length mediolateral width and dorsopalmar height, and extensor and flexor lever arm lengths were taken using digital Mitutoyo sliding calipers. MANOVAs of linear and CSGP traits demonstrate significant differences in locomotor groups (Pillai's Trace = 0.7206; p=0.0007). Discriminant function analysis shows this is motivated by J and the proportion of mediolateral width to dorsopalmar height of the phalangeal mid-length. We then subjected these properties to phylogenetic models assessing evolutionary models of Brownian motion (using R packages ‘bayou’ and ‘OUwie’). Results present little evidence for shared selective regime changes among taxa. One notable model results indicates selective shifts that occurred among taxa that evolved from an ancestral state of mediolaterally narrow phalanges to broader phalanges (as would be associated with fossorial behaviors). Thus, while convergences in shape and CSGP that relate to locomotor behavior are observed among taxa, phylogenetic comparative methods support selection as occurring only in species that evolved from a narrow to broader ungual phalanx morphology. Further analyses using OU models were used to assess phylogenetic models of convergence.

Estimation of body mass in white-tailed deer (Odocoileus virginianus) using cross-sectional geometry of the metapodial

Zooarchaeologists have developed and used several techniques for estimating the body mass of individual prey animals. Many of these are based on skeletal variables such as minimum number of individuals, weight of remains, or linear dimensions of long bone articular ends. All of these techniques fail to account for individual variability in body mass across the lifespan driven by the primary productivity of the landscape, sex, ontogeny, and season of individual death. Because skeletons are weight-bearing, they constantly remodel in response to changes in body mass, making long bone cross-sectional properties an ideal metric for predicting body mass. Cross-sectional geometric properties of distal limb bones and body mass of white-tailed deer (Odocoileus virginianus) were measured in a sample of 64 recently harvested individuals. Best-fit regressions between cross-sectional skeletal dimensions and dressed body weight produce higher R-squared values and lower standard errors of the estimate than regressions between dressed body weight and linear dimensions of long bone articular ends. Cross-sectional geometry can provide new useful line of evidence for estimating body mass of prey animals, when available.

Small body size phenotypes among Middle and Later Stone Age Southern Africans

Modern humans originated between 300 and 200 ka in structured populations throughout Africa, characterized by regional interaction and diversity. Acknowledgment of this complex Pleistocene population structure raises new questions about the emergence of phenotypic diversity. Holocene Southern African Later Stone Age (LSA) skeletons and descendant Khoe-San peoples have small adult body sizes that may reflect long-term adaptation to the Cape environment. Pleistocene Southern African adult body sizes are not well characterized, but some postcranial elements are available. The most numerous Pleistocene postcranial skeletal remains come from Klasies River Mouth on the Southern Cape coast of South Africa. We compare the morphology of these skeletal elements with globally sampled Holocene groups encompassing diverse adult body sizes and shapes (n = 287) to investigate whether there is evidence for phenotypic patterning. The adult Klasies River Mouth bones include most of a lumbar vertebra, and portions of a left clavicle, left proximal radius, right proximal ulna, and left first metatarsal. Linear dimensions, shape characteristics, and cross-sectional geometric properties of the Klasies River Mouth elements were compared using univariate and multivariate methods. Between-group principal component analyses group Klasies River Mouth elements, except the proximal ulna, with LSA Southern Africans. The similarity is driven by size. Klasies River Mouth metatarsal cross-sectional geometric properties indicate similar torsional and compressive strength to those from LSA Southern Africans. Phenotypic expressions of small-bodied adult morphology in Marine Isotope Stages 5 and 1 suggest this phenotype may represent local convergent adaptation to life in the Cape.

Numerical investigation of FRP-confined short square RC columns

Finite element (FE) simulation of confined RC columns is a complex task, as it involves the precise representation of a concrete material model that could express the volumetric change of concrete under a triaxial state of stress. The problem of confining RC columns using fiber-reinforced polymer (FRP) is more complex. This is due to the passive nature of FRP containment. Recently, the concrete damage plasticity (CDP) model available in an FE software product (ABAQUS) has been widely used to represent RC columns subjected to axial loading. The present paper aims to calibrate the concrete dilatancy angle and viscoplastic regularization parameters in the CDP model for the applications of square RC columns confined with FRP sheets. Ten experimental FRP-confined RC column specimens are incorporated in the calibration. In addition, a parametric study is investigated, including 96 cases, to obtain the influence of various design variables on the ratio between the confined to unconfined concrete compressive strength (fcc/fc). Four design variables are considered (i.e., the corner radius, concrete compressive strength, FRP reinforcement ratio, and cross-sectional size of columns). The study also focuses on assessing the reliability of four design codes: ACI-440, ECP-208, CSA-S806 and FIB-Bulletin-14. The numerical results show that a viscoplastic regularization with a fixed value equal to 0.0005 could provide accurate behavior. Nevertheless, the dilation angle cannot be considered a fixed value and should be related to the confinement degree coefficient Cd, which depends on the cross-sectional geometrical and FRP properties. Among the four considered design codes, ACI-440 and ECP-208 provide more accurate behavior than CSA-S806 and FIB-Bulletin-14.

The impact of activity on pelvic age‐at‐death estimation

AbstractThis study assesses whether greater levels of physical activity result in increased rates of degenerative change in the pubic symphysis and the iliac auricular surface. The sample comprises 131 skeletons from the Athens Collection. Skeletal age‐at‐death was estimated from the pubic symphysis and the iliac auricular surface. Skeletal activity was assessed using femoral cross‐sectional geometric (CSG) properties and fibrocartilaginous entheses. The association between skeletal age stages, CSG properties and entheseal changes (EC) was tested using Spearman correlation followed with partial Spearman correlation controlling for the effect of documented age‐at‐death and estimated body mass, as well as generalised linear models. Moreover, Kruskal–Wallis tests were used to compare the EC and CSG values among individuals who were underaged, correctly aged and overaged using the pubic symphysis and the iliac auricular surface. Our results show a negative correlation of skeletal age stages with particular CSG properties, implying a decrease in skeletal rigidity as age increases, and a positive correlation with EC scores, suggesting that older individuals exhibit more pronounced EC. Controlling for documented age‐at‐death and body mass produced low correlation coefficients and very few statistically significant results. The difference in EC and CSG values among underaged, correctly aged and overaged individuals was significant only for ECs in individuals over 50 years old. The present study highlights that the effect of activity on pelvic age markers is not pronounced, because a limited association between activity and skeletal degeneration in the pubic symphysis and iliac auricular surface was found. Considering the difficulty in identifying past occupations skeletally, our study supports that this often missing parameter in past osteobiographies does not affect skeletal age estimation. Moreover, our results suggest that taking into account the EC scores when evaluating skeletal age can provide further insights in age‐at‐death estimation in older individuals.

Advancements in sex estimation using the diaphyseal cross-sectional geometric properties of the lower and upper limbs.

This paper introduces an automated method for estimating sex from the lower and upper limbs based on diaphyseal CSG properties. The proposed method was developed and evaluated using 389 femurs, 412 tibias, and 404 humeri of adult individuals from a modern Greek reference sample, the Athens Collection. The skeletal properties, which were extracted with the CSG-Toolkit, were analyzed with step-wise DFA (evaluated with LOOCV) and subsequently with RBF kernel SVM supervised learning. SVM cross-validation was based on a 20-fold stratified random sample splitting as well as a chronological split based on year of birth to further assess the effect of secular change in sex estimation capacity. Maximum cross-validated classification accuracy from step-wise DFA reached 94.8% for the femur, 94.7% for the tibia, and 97.3% for the humerus, whereas SVM cross-validated results were similar although slightly lower, mainly due to the more strict cross-validation scheme. Our results suggest that the proposed sex estimation method is reasonably robust to secular change, since there was limited loss in classification accuracy between different chronological groups, despite the presence of secular change in stature of the Greek population during the examined period. The proposed method has been implemented as a function for the GNU Octave environment, named estimate_sex, which comprises a self-intuitive graphical user interface for facilitating sex estimation and is freely available under a suitable license.

Dorso-palmar elongation of the diaphysis of the third metacarpal bone in prehistoric Jomon people.

This study investigated cross-sectional morphological differences in the diaphysis of the third metacarpal bone (MC3) between prehistoric Jomon hunter-gatherers and modern Japanese people. Overall, 179 skeletal remains of 119 individuals (73 men and 46 women) from the Middle-to-Final Jomon period (3500 BC-500 BC) and 60 modern Japanese people (35 men and 25 women) were included in the analysis. Analyses were performed at the mid-shaft of the MC3 using linear measurement, elliptic Fourier analysis, and cross-sectional geometric properties. The standardized polar section modulus (ZpSTD) indicated sexual differences in both populations. The right MC3 was generally stronger than the left side. There was no populational difference in the ZpSTD in both sexes. In both men and women, the cross-sectional shape of the MC3 was relatively larger in the dorso-palmar direction than in the radioulnar direction in the Jomon population compared to the modern Japanese population. Sexual differences in cross-sectional shape were recognized only in the Jomon population, with the dorso-palmar elongation being greater in Jomon men than in women (particularly when comparing the left MC3). There was a significant side difference in the diaphyseal shape among Jomon women, with the right MC3 being relatively larger in the dorso-palmar direction. These findings were consistent, although skeletal remains of the Jomon population were excavated from different regions. Differences in the diaphyseal cross-sectional shape between populations suggest differences in habitual loading on MC3 associated with differences in subsistence behavior. Furthermore, differences in diaphyseal shape and strength between Jomon men and women suggest sexual division of labor, with men performing bimanual tasks and women performing unimanual tasks.

Advances in Osteometric Sorting: Utilizing Diaphyseal CSG Properties for Lower Limb Skeletal Pair-Matching.

Pair-matching of bilateral elements is a major component of resolving commingled remains both in forensic and bioarchaeological contexts. This study presents a new method of osteometric pair-matching of the lower limbs which relies on 3D digital models of the femur and tibia bones. The proposed method, which is accompanied by a freely available open-source implementation, automatically computes a number of osteometric variables including cross-sectional geometric properties from an assemblage of left and right bone antimeres and calculates probabilistically the appropriate matching pairs as well as single elements, whose bones antimere is not present in the given assemblage. The method has been extensively tested on a skeletal sample comprising 396 femurs and 422 tibias from the Athens collection. Our results in testing commingled assemblages with no disparity show that the method's sensitivity is 1 for sorting femurs and 0.997 for sorting tibias, whereas in assemblages with moderate disparity the sensitivity is 0.999 and 0.992 respectively. Our results further indicate that sensitivity is unaffected by the size of the commingled assemblage although the percentage of identified true matching pairs drops as the number of commingled elements increases. This means that all identified antimeres matched to an individual are still very accurately sorted despite not every individual being identified in very large assemblages. The proposed method can facilitate the sorting process of commingled remains both accurately and efficiently, while leaving a very small percentage of unsorted elements that may require further techniques for further individualization.

An examination of the cross-sectional geometrical properties of the long bone diaphyses of Holocene foragers from Roonka, South Australia.

This study examines long bone diaphyseal rigidity and shape of hunter-gatherers at Roonka to make inferences about subsistence strategies and mobility of inhabitants of semi-arid southeastern Australia. Roonka is a cemetery site adjacent to the Lower Murray River, which contains over 200 individuals buried throughout the Holocene. Archaeological evidence indicates that populations living near this river corridor employed mobile, risk averse foraging strategies. This prediction of lifestyle was tested by comparing the cross-sectional geometric properties of the humerus, radius, ulna, femur, tibia, and fibula of individuals from Roonka to samples of varying subsistence strategies. Bilateral asymmetry of the upper limb bones was also examined. Roonka males and females have moderately high lower limb diaphyseal rigidity and shape. In the upper limb, females have low rigidity and bilateral asymmetry while males have moderately high rigidity and bilateral asymmetry. This pattern is similar to other foraging groups from Australia and southern Africa that have behaviorally adapted to arid and semi-arid environments. Lower limb results suggest that populations in the Lower Murray River Valley had relatively elevated foraging mobility. Upper limb rigidity and bilateral asymmetry indicate a sexual division of labor at Roonka. Females resemble other samples that had mixed subsistence strategies that involved hunting, gathering, and processing tasks. Males display a pattern similar to groups that preferentially hunted large game, but that supplemented this source with smaller game and riverine resources.