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Weiss E 《American journal of physical anthropology》2003,121(4):293-302
This study used an aggregate measure of robusticity (based on humeral areal and inertial cross-sectional components) to test the hypothesis that rowing on oceans led to more robust humeri than did rowing on rivers or not rowing at all. Results confirmed the hypothesis that male ocean-rowers had more robust humeri than did male river-rowers or nonrowers. However, although the females from the ocean-rowing populations did not row, they averaged more robust humeri than did females from the non-ocean-rowing populations. Males averaged greater robusticity than did females. The robusticity of ocean-rowing populations, therefore, does not seem to be due solely to bone remodeling resulting from strenuous rowing. Humeral robusticity is difficult to attribute to specific activities because, in humans, upper limbs are utilized for many activities. Some populations may have more robust humeri because certain environments require greater overall activity levels in order to survive. 相似文献
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V.S. Sparacello O.M. Pearson A. Coppa D. Marchi 《American journal of physical anthropology》2011,144(1):119-130
Cross‐sectional geometrical (CSG) properties of an Iron Age Samnite group from the Alfedena necropolis (Abruzzo, Italy, 2600–2400 B.P.) are compared with a Ligurian Neolithic sample (6000–5500 B.P.). In the period under examination, Samnites were organized in a tribal confederation led by patrilinear aristocracies, indicating incipient social stratification. In comparison, Neolithic society lacked clear signs of social hierarchy. The subsistence of both groups was mainly based on pastoralism and agriculture, but changes in habitual behavior are expected due to the socio‐economic transformations that characterized the Iron Age. The Samnites' warlike ideology suggests that unimanual weapon‐use and training would have become frequent for males. The intensification of agriculture and the adoption of transhumant pastoralism, performed by a smaller subset of the population, likely led to a lower average level of logistic mobility. The strongly genderized ideology of the period suggests a strict sexual division of labor, with women primarily performing sedentary tasks. CSG properties based on periosteal contours were calculated for humeri, femora, and tibiae (N = 61). Results corroborated the expectations: Alfedena males show substantial humeral bilateral asymmetry, indicating prevalent use of one arm, likely due to weapon training. In both sexes lower limb results indicate reduced mobility with respect to the Neolithic group. Sexual dimorphism is significant in both humeral asymmetry and lower limb indicators of mobility. Although both groups could be broadly defined as agropastoral based on archeological and historical evidence, CSG analysis confirmed important differences in habitual behavior. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
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Erin L. R. Simons Tobin L. Hieronymus Patrick M. O'Connor 《Journal of morphology》2011,272(8):958-971
Avian wing elements have been shown to experience both dorsoventral bending and torsional loads during flapping flight. However, not all birds use continuous flapping as a primary flight strategy. The pelecaniforms exhibit extraordinary diversity in flight mode, utilizing flapping, flap‐gliding, and soaring. Here we (1) characterize the cross‐sectional geometry of the three main wing bone (humerus, ulna, carpometacarpus), (2) use elements of beam theory to estimate resistance to loading, and (3) examine patterns of variation in hypothesized loading resistance relative to flight and diving mode in 16 species of pelecaniform birds. Patterns emerge that are common to all species, as well as some characteristics that are flight‐ and diving‐mode specific. In all birds examined, the distal most wing segment (carpometacarpus) is the most elliptical (relatively high Imax/Imin) at mid‐shaft, suggesting a shape optimized to resist bending loads in a dorsoventral direction. As primary flight feathers attach at an oblique angle relative to the long axis of the carpometacarpus, they are likely responsible for inducing bending of this element during flight. Moreover, among flight modes examined the flapping group (cormorants) exhibits more elliptical humeri and carpometacarpi than other flight modes, perhaps pertaining to the higher frequency of bending loads in these elements. The soaring birds (pelicans and gannets) exhibit wing elements with near‐circular cross‐sections and higher polar moments of area than in the flap and flap‐gliding birds, suggesting shapes optimized to offer increased resistance to torsional loads. This analysis of cross‐sectional geometry has enhanced our interpretation of how the wing elements are being loaded and ultimately how they are being used during normal activities. J. Morphol., 2011. © 2011 Wiley‐Liss,Inc. 相似文献
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The effects of behavioral modification on the skeletal morphology of the laboratory mouse (Mus musculus) are investigated. Climibing, with increrased prehensile use of the foot, is found to bring about significant changes in metatarsal and long bone morphology. Differences in metatarsal robusticity related to weight-bearing differences associated with different locomotor patterns are reported for a natural history setting for Peromyscus. 相似文献
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Long bone loading histories are commonly evaluated using a beam model by calculating cross-sectional second moments of areas (SMAs). Without in vivo strain data, SMA analyses commonly make two explicit or implicit assumptions. First, while it has long been known that axial compression superimposed on bending shifts neutral axes away from cross-sectional area centroids, most analyses assume that cross-sectional properties calculated through the area centroid approximate cross-sectional strength. Second, the orientation of maximum bending rigidity is often assumed to reflect the orientation of peak or habitual bending forces the bone experiences. These assumptions are tested in sheep in which rosette strain gauges mounted at three locations around the tibia and metatarsal midshafts measured in vivo strains during treadmill running at 1.5 m/sec. Calculated normal strain distributions confirm that the neutral axis of bending does not run through the midshaft centroid. In these animals, orientations of the principal centroidal axes around which maximum SMAs (Imax) are calculated are not in the same planes in which the bones experienced bending. Cross-sectional properties calculated using centroidal axes have substantial differences in magnitude (up to 55%) but high correlations in pattern compared to cross-sectional properties calculated around experimentally determined neutral axes. Thus interindividual comparisons of cross-sectional properties calculated from centroidal axes may be useful in terms of pattern, but are subject to high errors in terms of absolute values. In addition, cross-sectional properties do not necessarily provide reliable data on the orientations of loads to which bones are subjected. 相似文献
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Most mammals have deformable bodies, making it difficult to measure the size of living or freshly killed ones accurately. Because small rodents are common prey of many snakes, and because nearly all snakes swallow their prey whole, we explored four methods for determining the ingestible size (the smallest cross‐sectional area that the largest part of the rodent can be made into without breaking bones or dislocating joints) of 100 intact rodents, including 50 Musmusculus and 50 Rattus norvegicus. Cross‐sectional areas derived from maximal height and width of specimens at rest or the same specimens wrapped snout to pelvic girdle are roughly 1.5× higher than areas calculated either by the height and width of the same specimens rolled into cylinders or by volumetric displacement. Rolling rodents into cylinders reduces cross‐sectional area by straightening the vertebral column, lengthening the abdominal cavity, elevating the sternum, compressing the thoracic cavity, and protracting the shoulder joint, that is, changes similar to those seen in rodents eaten by snakes. Reduced major axis regression of the smallest attainable cross‐sectional area, y, on mass, x, shows that y (in log mm2) approximates 1.53x (in log grams)0.69 for rats and 1.63x0.64 for mice. Our results suggest that visual cues provided by live rodents might lead most predators, like snakes, to overestimate ingestible size and hence rarely attack prey too large to ingest. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc. 相似文献
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The purpose of this article is to investigate temporal shifts in skeletal robusticity to infer behavioral changes in two populations (Neolithic, NEOL and Medieval, MED) settled in the same geographic area but involved in different subsistence economies (pastoralism and coastal resources exploitation). This comparison allows us to test the hypothesis that occupational stress and mobility in the same environment produce predictable changes in the robusticity of both upper and lower limbs. Results show a lower degree of humeral robusticity and a similar degree of humeral asymmetry in the two sexes in the MED population. These results are consistent with the relatively less stressful subsistence economy documented in the MED population relative to that of the NEOL. Lower limb results suggest that femoral robusticity does not correlate directly with the level of logistical mobility, but is instead due to the summation of several diverse factors that place biomechanical loads on the hindlimb, particularly unevenness of the terrain. However, female femoral gracility seems to indicate that below a certain \"threshold\" of mobility, i.e., movement over the natural terrain, terrain conformation is no longer the main contributing factor to femoral robusticity. The femoral shape index I(x)/I(y) declines through time, particularly in males. This agrees with the expected mobility of the samples based on archaeological and historical data, providing further evidence on the reliability of this index in inferring terrestrial mobility. 相似文献
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Elizabeth Weiss 《American journal of physical anthropology》2009,140(1):19-24
This study uses two prehistoric Amerindian populations of hunter‐gatherer subsistence patterns to determine whether levels of sexual dimorphism in humeral bilateral cross‐sectional asymmetry are related to sex‐specific differences in activities among these populations. Results confirmed that males of the California Amerind population who engaged in the more unimanual activities of spear hunting and warfare were more asymmetrical than were their female counterparts who engaged in the more bimanual activities of grinding acorns. California Amerind males were also more asymmetrical than British Columbian Amerind males who rowed (using both arms) extensively. Sex differences within British Columbian Amerinds were not statistically significant, nor were female differences between populations. In general, levels of humeral asymmetry appear to be more dependent on sex and population‐specific behaviors rather than broad subsistence patterns. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc. 相似文献
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Nikita E Siew YY Stock J Mattingly D Lahr MM 《American journal of physical anthropology》2011,146(3):423-434
The Garamantian civilization flourished in modern Fezzan, Libya, between 900 BC and 500 AD, during which the aridification of the Sahara was well established. Study of the archaeological remains suggests a population successful at coping with a harsh environment of high and fluctuating temperatures and reduced water and food resources. This study explores the activity patterns of the Garamantes by means of cross-sectional geometric properties. Long bone diaphyseal shape and rigidity are compared between the Garamantes and populations from Egypt and Sudan, namely from the sites of Kerma, el-Badari, and Jebel Moya, to determine whether the Garamantian daily activities were more strenuous than those of other North African populations. Moreover, sexual dimorphism and bilateral asymmetry are assessed at an intra- and inter-population level. The inter-population comparisons showed the Garamantes not to be more robust than the comparative populations, suggesting that the daily Garamantian activities necessary for survival in the Sahara Desert did not generally impose greater loads than those of other North African populations. Sexual dimorphism and bilateral asymmetry in almost all geometric properties of the long limbs were comparatively low among the Garamantes. Only the lower limbs were significantly stronger among males than females, possibly due to higher levels of mobility associated with herding. The lack of systematic bilateral asymmetry in cross-sectional geometric properties may relate to the involvement of the population in bilaterally intensive activities or the lack of regular repetition of unilateral activities. 相似文献
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Ian J. Wallace Kevin M. Middleton Svetlana Lublinsky Scott A. Kelly Stefan Judex Theodore Garland Jr. Brigitte Demes 《American journal of physical anthropology》2010,143(1):21-30
Limb bone diaphyseal structure is frequently used to infer hominin activity levels from skeletal remains, an approach based on the well‐documented ability of bone to adjust to its loading environment during life. However, diaphyseal structure is also determined in part by genetic factors. This study investigates the possibility that genetic variation underlying diaphyseal structure is influenced by the activity levels of ancestral populations and might also have functional significance in an evolutionary context. We adopted an experimental evolution approach and tested for differences in femoral diaphyseal structure in 1‐week‐old mice from a line that had been artificially selected (45 generations) for high voluntary wheel running and non‐selected controls. As adults, selected mice are significantly more active on wheels and in home cages, and have thicker diaphyses. Structural differences at 1 week can be assumed to primarily reflect the effects of selective breeding rather than direct mechanical stimuli, given that the onset of locomotion in mice is shortly after Day 7. We hypothesized that if genetically determined diaphyseal structure reflects the activity patterns of members of a lineage, then selected animals will have relatively larger diaphyseal dimensions at 1 week compared to controls. The results provide strong support for this hypothesis and suggest that limb bone cross sections may not always only reflect the activity levels of particular fossil individuals, but also convey an evolutionary signal providing information about hominin activity in the past. Am J Phys Anthropol 143:21–30, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
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Objective: To determine, using computer tomography (CT), whether the retention of a small number of teeth in the older adult used to support overdentures could affect the cross‐sectional area (CSA) and X‐ray density of two jaw closing muscles. Design: Cross‐sectional study of a group of older patients subdivided into dentate, edentulous and those wearing overdentures supported by two to five teeth. Subjects: The sample consisted of 24 subjects aged 55–68 years. Outcome measures: CSA and X‐ray density of two jaw closing muscles, masseter and medial pterygoid were measured and evaluated using CT. Results: There were no significant differences between left and right jaw muscles, but the CSA of the masseter muscles were significantly larger than the medial pterygoid muscles. The CSA of the masseter and medial pterygoid muscles was significantly smaller in edentulous subjects compared with dentate subjects but no significant difference was observed between subjects wearing overdentures and those with a natural dentition. No significant differences were observed with the X‐ray density between different muscles or dental states. Conclusion: The retention of a small number of teeth in the older adult used to support overdentures appears to sustain the CSA of two jaw closing muscles and therefore could enhance these patients’ masticatory ability compared with those who were edentulous. 相似文献
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Objective: Various factors may be associated with edentulism in elderly people. Association of total tooth loss with smoking, alcohol intake and nutrition in non‐institutionalised elderly Japanese was assessed utilising national database. Materials and methods: Records of independent surveys, the Survey of Dental Diseases (SDD) and the National Nutrition Survey (NNS) in 1999 were electronically linked using the household identification number. Results: Among the records of 6903 subjects in the SDD and 12 763 subjects in the NNS, 6805 records were successfully linked. Overall, prevalence of total tooth loss in adults was very similar in males and females at approximately 7.0%, and the smoking rate was 47.6% and 9.9% respectively. Total tooth loss was a rare phenomenon (<2%) in age groups of <60 years. According to the multiple logistic regression analysis involving 2200 subjects aged 60 years or older, significant variables were age, current smokers and vitamin C intake in males, and age and current smokers in females. The variable for current drinkers was significant in females but the odds ratio was <1.0. No significant relationship was detected with respect to former smokers and drinkers, body mass index, vitamin E intake and blood glucose level. Conclusions: Current smoking was associated with total tooth loss, although smoking rate was low in females. Gender difference in the association was suggestive with respect to drinking alcohol and vitamin C intake. 相似文献