bluuebunny/crossref_metadata_2025 huggingface dataset:
Diabetes, the ice free corridor, and the Paleoindian settlement of North America
Authors: Wendorf Michael
Published: February 2006

Since the 1940s, many Amerindian populations, including some with mixed Amerindian ancestry, have experienced an epidemic of obesity and adult‐onset diabetes (NIDDM). Obesity and NIDDM were apparently rare among Amerindian populations prior to that time. Though the evidence is equivocal, obesity and NIDDM seem to be rare today among Athapaskan Amerindians of the North American Arctic, sub‐Arctic, and Southwest.

It is hypothesized that the Amerindian genotype(s) susceptible to obesity and NIDDM arose from selection favoring “thrifty” genes during the peopling of North America south of the continental glaciers. “Thrifty” genes (Neel: Am. J. Hum. Genet. 14:353–362, 1962) allowed a more efficient food metabolism as hunter‐gatherers from an unusually harsh mid‐latitude tundra environment (the “ice free” corridor) adapted to more typical mid‐latitude environments to the south. The early Paleoindian settlement pattern from Wyoming to Arizona and Texas indicates a relatively brief period of reliance on unpredictable big game resources in lower elevations and smaller game and gathered resources in higher elevations. This unusual “specialist” settlement pattern may have resulted from the early Paleoindian's unfamiliarity with gathered foods and small game in lower elevations.

Athapaskan populations evidently moved south from Beringia sometime after the Paleoindian migration when the “ice free” corridor had widened and contained environments and resources more typical of subarctic latitudes. Thus, Athapaskan hunter‐gatherers could gradually adapt to the resources of lower latitudes such that “thrifty” genes would not have been as advantageous.

The interaction of recently introduced “western” diets and “thrifty” genes have evidently led to today's epidemic of obesity and NIDDM among Amerindians of Paleoindian ancestry.
Appearance of a labial notch in maxillary incisors: A population survey
Authors: Brin Ilana , Ben‐Bassat Yocheved
Published: February 2006

A labiogingival notch appearing on the enamel of maxillary central incisors seems to be a potential factor for compromised gingival and dental health. The objective of the survey was to describe the phenomenon and its prevalence in a random Israeli population. One thousand eight hundred eighty children with fully erupted permanent incisors were clinically examined. The appearance of the labiogingival notch on the enamel surface of the maxillary central incisors was determined. Two depth categories of the phenomenon were distinguished by probing. The possible differences in the prevalence of the labial notch appearance, between the sexes as well as between the right and left sides, were statistically evaluated. The prevalence of the labial notch on at least one incisor in the population examined was 6.5% (5.1% unilaterally and 1.4% bilaterally). No significant difference between the sexes regarding the appearance of this phenomenon was found. The shallow notch was similarly distributed between the right and left sides in both sexes. However, the deeper malformations appeared significantly more on the left side in boys (P < 0.05) and in girls (P < 0.01). The gingivae tended to follow the enamel contour; however, only in few cases was gingival inflammation or incipient caries diagnosed. It was concluded that the labio‐gingival notch is not a rare phenomenon, and it should be given special attention to prevent possible damage to the dental and gingival tissues.
Genetic structure of three Naikpod subpopulations of Andhra Pradesh, India
Authors: Muralidhar B. , Goud J. D. , Murty J. S.
Published: February 2006

The genetic structure of three subpopulations of the Naikpod tribe of Andhra Pradesh, India, was examined by studying three blood group, six red cell enzyme, and five protein systems and phenylthiocarbamide taste sensitivity. The gene frequency data of 15 loci are compared among the subpopulations as well as with those reported for other population groups from India. The analysis of gene diversity revealed that the gene differentiation among the subpopulations relative to total population is only 0.02, indicating that the genetic differentiation between subpopulations is very small compared with that within them. This is corroborated by the small genetic distances found among them. The effect of differentiation of microgeographical and breeding isolation on gene diversity and genetic differentiation among the three subpopulations is apparently low.
Variation in pelvic size between males and females
Authors: Tague Robert G.
Published: February 2006

Selection intensity and phenotypic variability are inversely related. It has been hypothesized that, owing to opposing selection pressures on pelvic morphology in females between efficiency in locomotion and obstetric adequacy, female pelvic morphology is less variable than that in males. The hypothesis was supported based on data derived from observational methods of sexing pelves (Meindl et al., 1985). The hypothesis was tested in the present study based on a metrical analysis of the true pelvis. The results show that there are no sexual differences in pelvic variability. Consequently, while males and females are equally variable in the dimensions of the true pelvis, the visual cues that osteologists use to sex pelves are more variable in males.
Live primates and dental replication: New problems and new techniques
Authors: Teaford Mark F. , Oyen Ordean J.
Published: February 2006

Dental microwear analyses are beginning to provide new insights into the intricacies of jaw movement and tooth use in modern and extinct mammals. However, these analyses are also raising new questions that are best answered through studies of live animals with known diets. The process of taking dental impressions from live animals is a difficult one that presents problems different from those encountered in working with museum material. This report presents a review of some of those problems together with solutions that have been developed in the course of laboratory work with nonhuman primates. It also summarizes recent developments in dental casting.
Fluorochrome labelling in roman period skeletons from dakhleh oasis, Egypt
Authors: Cook Megan , Molto El , Anderson C.
Published: February 2006

A histological aging study of femoral midshafts in a late Roman period sample from the Dakhleh Oasis, Egypt, showed discrete fluorochrome labelling. The fluorochome is yellow‐green in colour and fluoresces at a wavelength of 525 nm. The labelling occurs at the mineralization fronts and is so distinct that several histomorphometric measurements were made. The percent labelled surface values ranged from 6.03% to 59.34%, and the mean distance between labels ranged from 13.57 to 20.63 μm. Teeth from several individuals were also labelled within the enamel matrix. Comparisons were made between the patterns of fluorescent labelling from this population and from patients treated with interval and continuous dosages of tetracycline. The results collectively indicate that the fluorochrome is most likely tetracycline that made its way into the bone (in vivo) via stored grain contaminated by Streptomycetes. The labelling was differential, much like that of the patient on interval doses of tetracycline, so it is argued that the tetracycline was ingested occasionally, probably on a seasonal basis. The lack of bone infection in the adults (n = 29) suggests that the tetracycline may have provided some antibiotic protection in this population.
Time of fusion of the human sternebrae with one another in northwest India
Authors: Jit Indar , Kaur Harbir
Published: February 2006

The time of fusion of the sternebrae with one another was studied in sterna obtained from cadavers of 806 male and 212 female adults and 66 male and 29 female children, on whom medicolegal postmortem examinations had been conducted by the senior author. Sterna of 31 neonates were also studied. The bones were X‐rayed in an anteroposterior view and later macerated, cleaned, and dried. The sternebrae fused with one another from below upwards. In both sexes, the third and fourth sternebrae showed partial or commencement of fusion in a majority of specimens in the 0–5 years age group. Although the earliest complete fusion was seen in the 6–10 years age group, 100% specimens exhibited complete fusion in the 15–17 years age group. The earliest complete fusion between second and third sternebrae was observed in the 11–14 years age group in both sexes; it was seen in 100% of specimens in males over 25 years and in females over 30 years. The first and second segments showed earliest complete fusion in a boy of 16 years and in a girl of 18 years; 100% of specimens showed complete fusion in the males over 60 years and in the females over 30 years. A mesosternum showing complete fusion of all the sternebrae must be from a subject over 16 years of age if male and over 18 years if female. These observations are at variance with those of workers in Western countries. There has been no other report from India on this subject.
Spatial patterns of human gene frequencies in Europe
Authors: Sokal Robert R. , Harding Rosalind M. , Oden Neal L.
Published: February 2006

The aims of this study of spatial patterns of human gene frequencies in Europe are twofold. One is to present new methodology developed for the analysis of such data. The other is to report on the diversity of spatial patterns observed in Europe and their interpretation as evidence of population processes. Spatial variation in 59 allele and haplotype frequencies (26 genetic systems) for polymorphisms in blood antigens, enzymes, and proteins is analyzed for an aggregate of 3,384 localities, using homogeneity tests, one‐dimensional and directional spatial correlograms, and SYMAP interpolated surfaces. The data matrices are reduced to reveal the principal patterns by clustering techniques.

The findings of this study can be summarized as follows: 1) There is significant heterogeneity in allele frequencies among the localities for all but one genetic system. 2) There are significant spatial patterns for most allele frequencies. 3) There is a substantial minority of clinal patterns in these populations. Clinal trends are found more frequently in HLA alleles than for other variables. North‐south and northwest‐southwest gradients predominate. 4) There is a strong decline in overall genetic similarity with geographic distance for most variables. 5) There are few, if any, appreciable correlations in pairs of allele frequencies over the continent, and there is little interesting correlation structure in the resulting correlation matrix. 6) Few spatial correlograms are markedly similar to each other, yet they form well‐defined clusters. Spatial variation patterns, therefore, differ among allele frequencies.

Patterns of human gene frequencies in modern Europe are diverse and complex. No single model suffices for interpretation of the observed genetic structure. Some clinal patterns reported here support the Neolithic demicexpansion hypothesis, others suggest latitudinal selection. Most of the clinal patterns are in HLA alleles, but there is also evidence from ABO for east‐west migration diffusion. The majority of patterns are patchy, consistent with hypotheses of isolation by distance or of settlement of genetically differing, subsequently expanding ethnic groups. While undoubtedly there has been an ongoing stochastic process of differentiation consistent with the isolationby‐distance model, this has not obscured the directional patterns caused by migration (demic diffusion), and has perhaps only reinforced the contribution from settlement of ethnic units to patterns of genetic variation. However, the impact of the latter is most difficult to discern and requires further methodological developments.
Maxillary canine microwear in Dryopithecus from Spain
Authors: Puech Pierre‐Francois , Cianfarani Francois , Ribot I Trafi Francesc
Published: February 2006

The three functional domains of the upper canines of Dryopithecus from Spain are analysed through microscopic examination. Evidence is presented that shows a food choice in concordance with open woodland habitat.
Cranial injuries as evidence of violence in prehistoric southern California
Authors: Walker Phillip L.
Published: February 2006

Crania from the Channel Island area of southern California were examined for evidence of traumatic injuries. Well‐healed depressed fractures in the outer table of the cranial vault are common in skeletal remains from the northern Channel Islands (18.56% n = 598) but rare in those from the mainland coast (7.5% n = 146). This prevalence of traumatic injuries among the islanders may be a result of intense competition over resources in a geographically circumscribed environment. The frequency of cranial injuries increases significantly between the early and late prehistoric periods on the Channel Islands. This temporal variation appears to reflect changes in patterns of violence associated with population growth and environmental instability.
Food transport through the anterior oral cavity in macaques
Authors: German R. Z. , Saxe S. A. , Crompton A. W. , Hiiemae K. M.
Published: February 2006

Intraoral transport, the movement of food or liquid through the oral cavity and oropharynx, is a major component of feeding behavior. Stage I transport, transport through the oral cavity prior to mastication, has been described for several mammals (Franks et al.: Arch. Oral Biol. 30:539, 1985; Hiiemae and Crompton: Hildebrand et al. (eds.): Functional Vertebrate Morphology, Cambridge, MA, Belknap Press, 1985). Previous work (Franks et al.: Am. J. Phys. Anthropol. 65:275, 1984) indicated that this was not a significant behavior in macaques in a laboratory setting, because food was ingested directly to the region of the cheek teeth. Although relatively infrequent in a captive situation, stage I transport does occur in long‐tailed macaques through a mechanism similar to other mammals, but also subject to unique aspects of primate anatomy. Transport takes several cycles during which the food moves back and forth in an anterior/posterior direction, due to tongue movements. Because anthropoid primates lack the pronounced rugae that in other mammals prevent the anterior displacement of a bolus, stage I transport uses the rounded arch of the upper, anterior dentition to hold the food during the forward movement of the tongue. During the final cycle of transport, a pronounced twisting of the tongue, along a midline anteroposterior axis helps funnel the food item toward the postcanine teeth for subsequent mastication. This twisting, which was described in humans by Abd‐El‐Malek (J. Anat. 100:215, 1955) but not within the context of jaw movement, occurs prior to the closing phase of the jaw cycle.
Sacral curvature and supine posture
Authors: Abitbol M. Maurice
Published: February 2006

Sacral curvature (SC), represented by the angle between the first and the last sacral vertebrae, is a feature that differentiates the human pelvis from that of other animals. The sacral curvature was measured and studied in 14 cebids, 31 cercopithecids, 17 hylobatids, 85 pongids, 23 normal human children, 15 children with orthopedic handicaps, 49 normal adult human males, and 64 normal adult human females. Sacral curvature was minimal to nil in monkeys (mean 11.5 ± 6 SD degrees), and moderate in apes (hylobatids, mean 16 ± 10 SD degrees; pongids, mean 27.2 ± 16 SD degrees). In human newborns SC is minimal, increasing progressively until adolescence, reaching a mean of 64.7 ± 29 SD degrees in adult humans. This study investigates the different factors contributing to the formation of the sacral curvature. These factors include 1) the effect of erect posture, which tilts the upper part of the sacrum dorsally and the lower part of the sacrum ventrally, and 2) the influence of supine posture, which affects the development of the lower part of the sacrum. In addition to supine posture the levator ani, which is well developed in Homo sapiens, also affects the lower part of the sacrum and coccyx and influences its ventral orientation. Variation in SC can result from differences in onset and frequency of supine posture. This is the first time that supine posture has been shown to play a role in shaping the human pelvis, although it is as characteristic of H. sapiens as is erect posture.
Olduvai hominid 7 trapezial metacarpal 1 articular morphology: Contrasts with recent humans
Authors: Trinkaus Erik
Published: February 2006

A consideration of the metacarpal 1 articulation of the Olduvai Hominid 7 trapezium shows that, although it is generally similar to those of recent humans, it is considerably flatter radioulnarly and dorsopalmarly than those of modern humans and similar in its degree of dorsopalmar flattening to those of Upper Pleistocene late archaic humans. Even though this flattening may have slightly limited flexion‐extension at the pollical carpometacarpal joint, it is most likely related to the apparently elevated levels of axial joint reaction force through the thumbs of archaic members of the genus Homo. It also documents the continuation of human carpometacarpal articular evolution through the Pleistocene.
In vivo and in vitro turnover in dental microwear
Authors: Teaford Mark F. , Oyen Ordean J.
Published: February 2006

Given the potential usefulness of dental microwear analyses in interpretations of archaeological and paleontological material, it is surprising how little we know about changes in individual microwear features through time. The purpose of this study was to document the turnover in primate dental microwear through in vivo dental studies of monkeys raised on different diets, and through in vitro studies of the abrasive effects of monkey chow biscuits on isolated monkey teeth. As in previous studies, epoxy replicas were prepared from dental impressions and examined under a scanning electron microscope.

Results indicate that, under certain conditions, the turnover in primate dental microwear can be on the order of days, hours, or even minutes. Individual microscopic wear features can be obliterated within 24 hours on the molars of laboratory monkeys, and monkey chow biscuits can easily scratch the enamel of isolated monkey teeth. Monkeys raised on a hard diet showed more rapid turnover in dental microwear than monkeys raised on a soft diet. However, paired‐sample tests revealed that, for all animals, the molar shearing facets were being abraded at a significantly slower rate than molar crushing/grinding facets.

In light of these results, investigators should make every effort to use large samples in interspecific comparisons of dental microwear involving species with variable diets. Another implication of these results is that changes in dental microwear might be useful indicators of changes in oral behavior over relatively short periods of time.
Inbreeding effects on fetal growth in Beirut, Lebanon
Authors: Khlat Myriam
Published: February 2006

Effects of consanguineous marriages on offspring's gestational age and anthropometrics at birth were investigated in Beirut through a hospital‐based survey of 1,252 newborns. Twenty‐five percent of all newborns were inbred, and the mean inbreeding coefficient was 1.25%. Neither prematurity rate nor weight, length, head circumference, and chest circumference (considered individually, or as a whole) showed a significant pattern by type of parental consanguinity. Failure to demonstrate significant inbreeding effects is reported in several other studies and generally interpreted as the long‐term result of continued inbreeding practices.
Meaning of biodistance statistics: A test case using adult monozygotic twins
Authors: Jamison Paul L. , Meier Robert J. , Thompson‐Jacob Dona
Published: February 2006

Anthropometry, historically one of the primary research techniques in physical anthropology, has been widely utilized in biodistance studies. The complex genetic and environmental interaction that governs the expression of anthropometric dimensions, together with concerns over measurement error, have sometimes clouded the interpretation of biodistances based upon anthropometry. In this study, 51 pairs of adult monozygotic twins were analysed using discriminant analysis and Mahalanobis' generalized distance. Both male and female twins, grouped by first‐ versus second‐born, displayed very small, statistically insignificant distances between groups. When literature estimates of intra‐observer measurement errors were used as a frame of reference, the average absolute differences between the twin pairs were approximately twice the size of the measurement error estimates. The results of this study suggest that, first, the environmental effect upon the genetically influenced traits measured by anthropometry is not large enough to bring about significant multivariate differences between identical twin pairs; and, second, biodistance studies based upon anthropometry can be reliable so long as measurement error is minimized.
Skeletal biological distance studies in American Physical Anthropology: Recent trends
Authors: Buikstra Jane E. , Frankenberg Susan R. , Konigsberg Lyle W.
Published: February 2006

Biological distance analysis, the dominant type of skeletal biological research during the 19th century, has become less visible in recent years. Although the proportion of American Journal of Physical Anthropology articles and published abstracts focusing on biodistance has remained fairly constant over the three decades between 1955 and 1985, the proportion of biodistance contributions relative to other skeletal biology studies has decreased. Emphasis in skeletal biology has shifted from the analysis of biological variation to investigations of health and diet, and within biodistance studies methodological issues have assumed prominence over purely analytical approaches. This paper investigates trends in biological distance analysis through a survey of articles and meetings abstracts published in the American Journal of Physical Anthropology from 1955 to 1985. The survey provides the historical context for five symposium papers on skeletal biological distance presented at the 1986 meeting of the American Association of Physical Anthropologists.
Population structure and skeletal variation in the Late Woodland of west‐central Illinois
Authors: Conner Michael D.
Published: February 2006

This paper analyzes nonmetric trait variation in 11 late Late Woodland (ca. AD 700–1000) and one Mississippian (AD 1000–1300) skeletal samples from west‐central Illinois from a population‐structure perspective. Most of the sites are of the Bluff phase of Late Woodland in the lower Illinois River valley; others are from a nearby, contemporary archaeological phase. Late Woodland as a whole era (ca. AD 250–1000) was a period of marked population growth and expansion into new regional environments, trends that accompanied horticultural intensification in the area. Overall variation between sites was low, but males, females, and the total sample exhibitied a significant geographic component to variation due to interregional morphological differences. The Bluff sites tended to group together relative to the non‐Bluff sites. However, there was no significant geographic component to variation among the Bluff sites. The results are only partially consistent with archaeological data suggesting population growth and expansion through fissioning. Previous studies have demonstrated significant heterogeneity for nonmetric trait frequencies among Middle Woodland (ca. 100 BC to AD 250) sites, suggesting a Middle to Late Woodland change in population structure that lowered levels of morphological variation. This supports a model of increased intra‐ and interregional interaction from Middle to Late Woodland times developed from ceramic data by Braun and by Braun and Plog.
Mylohyoid and jugular foramen bridging in pre‐columbian chileans
Authors: Sawyer Danny R. , Gianfortune Vincent , Kiely Michael L. , Allison Marvin J.
Published: February 2006

The occurrence of mylohyoid groove bridging and jugular foramen bridging was determined in a population of adult Pre‐Columbian Chileans. Two hundred forty‐one crania (110 males, 131 females) were examined for jugular foramen bridging and 464 mandibles (252 males and 212 females) were observed for mylohyoid groove bridging. The overall incidence of jugular foramen bridging was 14.94%, with females showing a higher occurrence (18.32%) than males (10.91%); however, no statistical significance was found between the sexes. The right side showed a greater incidence than the left, but again no statistical difference was noted and the occurrence of this trait was found to be associated between the sides. This frequency of jugular foramen bridging is higher than that found in other studies and approaches that reported in North American Eskimo populations. In the case of mylohyoid groove bridging, the incidence was 4.09% with no difference found between the sexes. This frequency of occurrence is less than the values reported previously for the other American populations of Mongoloid ancestry including the Pre‐Columbian Peruvian population. The importance of nonmetric skeletal traits for defining population groups and their usefulness as anthropological tools is discussed. It is concluded that hard tissue variations such as bony bridging may be reliable markers to aid in discretely identifying population groups, but their importance can be significantly enhanced by coupling as many traits as possible in future studies.
Relationships of epidermal ridge patterns with body measurements and their possible evolutionary significance
Authors: Loesch Danuta Z. , Lafranchi Maureen
Published: February 2006

It is commonly believed that in humans epidermal ridge patterns are in regression relative to nonhuman primates, and they play no role in adaptive processes. In contrast with this we have found relationships between anthropometric and dermatoglyphic measurements in a sample of 61 normal males. Anthropometric variables included limb, trunk, head, and face measures. Dermatoglyphic variables included finger ridge counts and pattern intensities and ridge breadth in the palmar interdigital area II. The strongest relationship is between the type and size of pattern on the thumb and the breadth of ridges, and wrist width, which accounts for nearly 30% of the total variance in these traits. These findings identify previously unknown sources of variation in dermatoglyphic patterns and indicate that the dermatoglyphic–anthropometric relationships might have resulted from selection pressures in evolution of modern man.
Sources of variation in interbirth intervals among captive bonnet macaques (Macaca radiata)
Authors: Silk Joan B.
Published: February 2006

Female fitness is a function of variation in the length of females' reproductive careers, the viability of their offspring, and the frequency with which they give birth. Infant loss shortens interbirth intervals in most primate species, but we know considerably less about other factors that contribute to variation in the length of interbirth intervals within groups. In one large captive group of bonnet macaques, maternal parity, age, experience, family size, and recent reproductive history are all associated with variation in the length of intervals that follow the birth of surviving infants. Primiparous females have the longest interbirth intervals, while multiparous females who have produced surviving infants in the past and have raised their last infant successfully have the shortest interbirth intervals. Infant sex and maternal rank have no direct effect upon the length of interbirth intervals. One of the underlying causes of variation in the length of interbirth intervals after surviving births seems to be variation in the timing of conceptions among females. Females who conceive early in the mating season tend to have shorter interbirth intervals than other females. However, females who are multiparous, experienced, and have recently raised infants have late conceptions and short interbirth intervals.
Concepts of occlusion: Australian evidence
Authors: Brown T. , Townsend G. C. , Richards L. C. , Burgess V. B.
Published: February 2006

Longitudinal studies of aboriginal children over a 20‐year period have drawn attention to the wide variation in morphological features of the dentition and the way in which occlusal relationships develop. This paper summarizes some important determinants of optimal occlusal development, namely, tooth size relationships within and between dentitions, the patterns of alveolar growth, and tooth migrations during the transition from primary to permanent teeth and the nature of growth changes in the dental arches. Dental occlusion constantly changes throughout life in response to changing functional requirements. Observations limited to cross‐sectional material provide an incomplete, and sometimes misleading, concept of dental occlusion and masticatory function.
Expression of the entoconulid (sixth cusp) on mandibular molar teeth of an Australian aboriginal population
Authors: Townsend Grant , Yamada Hiroyuki , Smith Patricia
Published: February 2006

The expression and genetic basis of the entoconulid (sixth cusp) on mandibular molars were examined in a geographically isolated group of aboriginals from Yuendumu in the Northern Territory of Australia. Four grades of trait expression, ranging from trace to small, medium, and large cusps, were defined on dental casts of 399 subjects. Frequencies of occurrence were among the highest reported in human populations. Approximately 80% of dm2s showed the trait, whereas frequencies in the permanent dentition ranged from around 50% on M2 to 70% on M1 and 80% on M3. The degree of expression increased distally along the molar series, with only 3% of dm2s showing large cusps compared with 25% of M3s. Fluctuating asymmetry was highest for M2 and lowest for dm2. No strong evidence for sexual dimorphism in occurrence or degree of expression was found.

Based on a quasi‐continuous threshold model, a genetic contribution to entoconulid variability was observed that was strongest for M1. Significant associations were noted between entoconulid expression on mandibular molars and metaconule expression on maxillary molars, indicating that similar developmental mechanisms may influence these traits. The entoconulid and the metaconule both provide additional bulk on the distal occlusal surface of molar teeth, an area subjected to early wear during mastication in aboriginals.
Polynesian face and dentition: Functional perspective
Authors: Kean M. R. , Houghton P.
Published: February 2006

Widely dispersed throughout the Pacific, Polynesians are a biologically distinctive people in form and size of both body and head. Largebodied and well‐muscled, their body phenotype is suited to life in a thermolabile oceanic environment. Their craniofacial skeleton is large and robust, with mandibular size and from (the “rocker” mandible) being especially characteristic. In this paper the Polynesian variants of body form, and of facial size (including dentition) and form, are interpreted from a functional perspective.
Tooth wear and temporomandibular joint change in Australian Aboriginal populations
Authors: Richards L. C.
Published: February 2006

The masticatory system consists of teeth, temporomandibular joints, and the supporting craniofacial skeleton. The form and function of each of these components of the system can be understood only within the overall context of the system.

In a series of studies, the complex relationships between tooth wear and temporomandibular joint morphology and pathology were considered in samples consisting of a total of 58 male and 54 female crania from two Australian Aboriginal populations. The extent and buccolingual direction of tooth wear were assessed using established techniques. Both metric and nonmetric description of temporomandibular joint morphology and pathology were developed.

Significant differences in patterns of tooth wear and in the frequencies of various temporomandibular joint changes were evident between sexes and between populations. Furthermore, significant correlations between a number of tooth and joint variables were also evident. In addition, there was clear evidence of relationships between both tooth wear and temporomandibular joint changes and craniofacial morphology.

The results of this study provide additional evidence of the complex relationships between the form and function of the masticatory system.
Patterns of enamel hypoplasia in two medieval populations from Nubia's Batn el Hajar
Authors: van Gerven Dennis P. , Beck Rosemary , Hummert James R.
Published: February 2006

Analysis of enamel hypoplasia frequencies for two medieval populations representing the earliest and latest Christian periods of ancient Nubia reveals important diachronic shifts in childhood stress. The mean frequency for hypoplastic bands among the early Christians is 4.2, while the late Christian sample has a mean frequency of 3.7. In addition, the earlier Christians show a prolongation of hypoplastic occurrences through childhood corresponding to a prolonged period of intensified childhood mortality. The modal time interval between hypoplastic occurrences is also shorter for the early Christian children.

A comparison of hypoplasia frequencies by sex also reveals a pattern of considerable interest. Females show both lower frequencies of hypoplasias as well as a delay in onset.

The diachronic differences are consistent with other indications from paleopathology and paleodemography that childhood stress decreased in later Christian times. The sex differences suggest that during the infancy and early childhood females were more resilient than their male counterparts.
The effects of population structure on the spread of the HIV infection
Authors: Sattenspiel Lisa , Koopman James , Simon Carl , Jacquez John A.
Published: February 2006

A model for the spread of human immunodeficiency virus (HIV) in a population of male homosexuals is presented. The population is divided into five groups on the basis of degree of sexual activity. Within each group, the individuals are classified as (1) susceptible; (2) infective; or (3) removed because of a lack of sexual activity associated with advanced acquired immunodeficiency disease (AIDS). The infective individuals are further subdivided into four stages of infection. Analyses of the model address two questions with regard to the spread of HIV: (1) What is the effect of level of sexual activity on an individual's risk for infection, and (2) What is the effect that assumptions about mixing between groups have on both individual risk and transmission throughout a population? Results from analyses using a number of different parameter estimates show that increased levels of sexual activity increase the likelihood that an individual will become infected. In addition, the initial spread of the disease is markedly affected by variation in the amount of contact among individuals from different subpopulations. The steady‐state incidence of the disease is not markedly affected by variation in the contact patterns, but the size of the steady‐state population and therefore the proportion of infected individuals in the population does vary significantly with changes in the degree of mixing among subpopulations. These results show clearly the sensitivity of model outcomes to variation in the patterns of contact among individuals and the need for better data on such interactions to aid in understanding and predicting the spread of HIV.
Rheumatoid arthritis “in the buff”: Erosive arthritis in defleshed bones
Authors: Rothschild Bruce M. , Woods Robert J. , Ortel Wade
Published: February 2006

Examination of isolated bones from patients with unequivocal rheumatoid arthritis provides only a glimpse of the disease but has been the only “gold standard” for recognition of osseous lesions as compatible with the diagnosis of rheumatoid arthritis. Documentation of skeletal pathologic changes in confidently diagnosed individuals has been a major missing link in the transition from clinical to skeletal analysis. Availability of appropriate skeletal material from two patients with long‐standing, well‐documented rheumatoid arthritis provided the opportunity for acquiring such information. The osseous appearance, skeletal distribution, and distinguishing features of rheumatoid arthritis “in the buff” were delineated in two contemporary patients and in a skeletal population of 2,906 individuals. The preconceived notion of anticipated severity of disease has hereby been tested and found wanting. Severe lesions are not recognizable or distinguishable from artifact in relatively fragile rheumatoid arthritis‐affected bones, whether freshly prepared or remotely sampled. Characterization of the nature and epidemiology of osseous alterations in two contemporary skeletal populations permitted the development of a standard for recognition of the disease in skeletal populations.
Continuing periosteal apposition I: Documentation, hypotheses, and interpretation
Authors: Lazenby Richard A.
Published: February 2006

Continuing periosteal apposition (CPA) of small amounts of new lamellar bone, leading to absolutely larger size, has been identified in a number of adult cranial and postcranial bones. This paper reviews 42 studies published since 1964 that have found both significant and nonsignificant age‐related change in various skeletal size dimensions, e.g., length, diameter, width, and area. Also considered are four hypotheses that have, or may be, postulated for the occurrence of CPA. To date, however, these hypotheses (cohort effect, mechanical compensation, bone repair and/or mechanical response potential, and heterochrony) have not been rigorously tested, hence remain speculative. An important interpretive problem that befalls the investigation of CPA is its small effect size (i.e., the magnitude of change between observations), since most studies have restricted sample sizes. This problem is illustrated by power analysis of three reviewed studies that reported nonsignificant age‐related change. The analysis indicates that these studies had very little likelihood of finding a statistically significant result, i.e., a low probability of rejecting the null hypothesis stipulating no size change with age. This finding has implications for interpreting CPA and for distinguishing between the statistical and biological significance of this phenomenon.
Continuing periosteal apposition II: The significance of peak bone mass, strain equilibrium, and age‐related activity differentials for mechanical compensation in human tubular bones
Authors: Lazenby Richard A.
Published: February 2006

It is generally presumed that compensation for the reduction of bone strength by progressive endosteal bone loss in adults is provided by continuing periosteal apposition (CPA) of new lamellar bone. However, the appropriate magnitude of compensatory bone growth, and the parameters that operate to determine that magnitude, are unknown. This paper examines the mechanical compensation hypothesis in a series of right‐circular tubular bone analogues. Under this hypothesis, the stated objective of CPA is maintenance of the cross‐sectional geometric properties of the element. These include the second and polar moments of area, as well as the cortical area of the section (I, J, and CA, respectively). This study assumes that, as resorption and apposition proceed, geometric change is isometric (shape preserving).

The analysis suggests that for a given rate of endosteal bone loss (the stimulus), the magnitude of periosteal growth (the response) required to maintain geometric strength is determined by the maximum ratio (CT0) of the radial distances from the section centroid to the endosteal and periosteal surfaces (i.e., cortical thickness prior to the onset of progressive endosteal bone loss, or peak bone mass). The analysis also indicates that, for any given individual, the amount of compensatory periosteal gain required may be very small. This is particularly true for individuals having a large CT0 and for whom the magnitude of dynamic loading imparted to the skeleton declines with advancing age. This finding is illustrated in a model that relates concepts of bone surface remodeling equilibria and age‐related activity differentials.
Comparison of muscle weight and force ratios in new and old world monkeys
Authors: Bouvier Marianne , Tsang Stephen M.
Published: February 2006

Thin mandibles and small incisors found in New World monkeys as compared with Old World monkeys suggest that there may be differences in craniofacial loading patterns between these two groups, particularly in levels of mandibular corpus twisting (Hylander, 1975, 1979a; Eaglen, 1984; Bouvier, 1986a,b). This study examined the hypothesis that changes in the relative force contributions of the masticatory muscles were responsible for lowering torsion on the mandibular corpus in New World monkeys. Muscle weight and physiological cross‐sections were compared using data from the literature (Schumacher, 1960; Turnbull, 1970; Cachel, 1979) as well as new data on adult male Cebus apella and Macaca mulatta. Both age and sex had an effect on muscle ratios. Mixed samples such as those used by Schumacher and Turnbull probably are not appropriate for drawing conclusions concerning species or group differences in muscle ratios. In addition, biomechanical conclusions based on muscle weight ratios alone to estimate muscle force may be misleading because fiber length inversely affects the amount of force a muscle can exert. A comparison of ratios based on physiological cross‐section as an estimator of muscle force in New and Old World monkeys does not support the hypothesis that alterations in force contribution by individual masticatory muscles are responsible for minimizing mandibular corpus twisting in New World monkeys. Therefore, if twisting has been minimized in New World monkeys as suggested by their thin corpora, other changes in the craniofacial musculoskeletal complex, such as different muscle recruitment or pinnation patterns, may be responsible.
Cladistics and the hominid fossil record
Authors: Trinkaus Erik
Published: February 2006

Cladistic methodology has become common in phylogenetic analyses of the hominid fossil record. Even though it has correctly placed emphasis on morphology for the primary determination of affinities between groups and on explicit statements regarding traits and methods employed in making phylogenetic assessments, cladistics nonetheless has limitations when applied to the hominid fossil record. These include (1) the uncritical assumption of parsimony, (2) uncertainties in the identification of homoplasies, (3) difficulties in the appropriate delimitation of samples for analysis, (4) failure to account for normal patterns of variation, (5) methodological problems with the appropriate identification of morphological traits involving issues of biological relevance, intercorrelation, primary versus secondary characters, and the use of continuous variables, (6) issues of polarity identification, and (7) problems in hypothesis testing. While cladistics has focused attention on alternative phylogenetic reconstructions in hominid paleontology and on explicit statements regarding their morphological and methodological underpinnings, its biological limitations are too abundant for it to be more than a heuristic device for the preliminary ordering of complex human paleontological and neontological data.
Metatarsophalangeal joints of Australopithecus afarensis
Authors: Latimer Bruce , Lovejoy C. Owen
Published: February 2006

Metatarsophalangeal joints from African pongids, modern humans, and Australopithecus afarensis are compared to investigate the anatomical and mechanical changes that accompanied the transition to terrestrial bipedality. Features analyzed include the shape and orientation of the metatarsal heads, excursion of the metatarsophalangeal joints, and orientation of the basal articular surface of the proximal phalanges. These features unequivocally segregate quadrupedal pongids and bipedal hominids and demonstrate a clear adaptation to terrestrial bipedality in the Hadar pedal skeleton.
Three‐dimensional computed tomography of the mummy Wenuhotep
Authors: Pickering Robert B. , Conces Dewey J. , Braunstein Ethan M. , Yurco Frank
Published: February 2006

Computed tomography allows cross‐sectional imaging of anthropological as well as clinical subjects. Recently, technical innovations have made three‐dimensional reconstruction of these images feasible. We performed two‐dimensional and three‐dimensional computed tomography of a Late Period Egyptian mummy to reexamine findings seen on previous radiographic studies and to evaluate the usefulness of these techniques in paleopathology.

Two‐dimensional images provided excellent anatomic detail. There was graphic depiction of the mummification process that corroborated information previously obtained from Egyptological studies. Three‐dimensional reconstruction provided images of facial features as if the mummy had been unwrapped.

Three‐dimensional computed tomography is a useful method of nondestructively evaluating paleopathological remains, and it may yield information not obtainable by any other means.
Caries experience in Mediaeval Scots
Authors: Kerr N. W. , Bruce M. F. , Cross J. F.
Published: February 2006

Dental caries prevalence, distribution, and site of attack was investigated in a Scottish Mediaeval population. The findings supported previous reports, which suggested that caries prevalence in Scotland was lower than in contemporaneous English populations. Attrition of the occlusal surface of the teeth with accompanying alteration of the anatomy of the interproximal space is suggested as the principal reason for the differences in the pattern of distribution of caries between this and modern populations.
Atresia of the external acoustic meatus in prehistoric populations
Authors: Hodges Denise C. , Harker Lee A. , Schermer Shirley J.
Published: February 2006

A case of atresia of the external acoustic meatus is presented from a prehistoric Late Woodland site in Iowa. The affected individual was a female aged 30 to 40 years. The left temporal bone displayed a thin bony plate occluding the external acoustic canal. No evidence of middle ear or inner ear malformation was observed on the axial tomographs, although the external canal was shortened. The individual is diagnosed as having a mild case of congenital atresia. The report extends the geographical and temporal distributions of this archaeologically rare condition.
Paleoepidemiology of a Central California prehistoric population from CA‐ALA‐329: II. Degenerative disease
Authors: Jurmain Robert
Published: February 2006

Degenerative lesions are scored and frequencies of involvement are computed for a skeletal collection from Ca‐Ala‐329, a prehistoric site on the southeastern side of San Francisco Bay, dating from 500 A.D. up to European contact. A large earthmound site, excavations conducted there by San Jose State University retrieved close to 300 burials. For this epidemiological analysis, reasonably complete and aged skeletons representing 77 adult females and 90 adult males are available. Degenerative changes are scored macroscopically in an ordinal fashion for the large fibro‐cartilagenous joints between adjacent vertebral bodies (vertebral osteophytosis) as well as the small apophyseal articulations of the spine. In addition, in the peripheral skeleton degenerative changes are scored in the temporo‐mandibular, shoulder, elbow, hip, and knee joints as well as the small articulations of the hands and feet. The most common degenerative changes in the spine are seen between the vertebral bodies of the lower lumbar region. In the peripheral skeleton the highest involvement of degenerative disease is seen in the hands and feet. Compared to other relevant osteological samples, this group of hunting‐gathering California Indians shows more degenerative changes than settled agriculturists (from Pecos Pueblo, New Mexico) but substantially less frequent involvement than in arctic hunters (Alaskan Eskimos).