Stephan Naji

Testing the Hypothesis of a Worldwide Neolithic Demographic Transition Corroboration from American Cemeteries

The signal of a major demographic change characterized by a relatively abrupt increase in the proportion of immature skeletons has been detected in a paleoanthropological database of 38 MesolithicNeolithic cemeteries from Europe and North Africa. From the Mesolithic to the Neolithic, the proportion of immature skeletons increases by 2030% over a period of 500700 years, indicating a notable increase in the crude birth rate. This shift has been called the Neolithic demographic transition. A similar signal has been detected in an independent set of archaeological data, namely, enclosures. This paper presents results from a sample of 62 cemeteries in North America (7,755 BP350 BP) that point to the same transition over a period of 600800 years.The signal of a major demographic change characterized by a relatively abrupt increase in the proportion of immature skeletons has been detected in a paleoanthropological database of 38 MesolithicNeolithic cemeteries from Europe and North Africa. From the Mesolithic to the Neolithic, the proportion of immature skeletons increases by 2030% over a period of 500700 years, indicating a notable increase in the crude birth rate. This shift has been called the Neolithic demographic transition. A similar signal has been detected in an independent set of archaeological data, namely, enclosures. This paper presents results from a sample of 62 cemeteries in North America (7,755 BP350 BP) that point to the same transition over a period of 600800 years.

The Signal of the Neolithic Demographic Transition in the Levant

In this chapter, we test the prediction of a Neolithic demographic transition in the Levant, with palaeoanthropological data from 31 cemeteries. The demographic profile obtained is the same as the profile obtained for Europe and North Africa and for North America, with a significant increase of the 15P5 values when the new farming economy emerges (dt=0), over a time span of more than 2000 years. However, the tempo of this transition in the epicentre of the transition to farming differs from the tempo in the peripheral areas: in the Levantine cemeteries the increase in immature skeletons is as high as in the rest of Europe but the time span in which it occurs is three times as long. The question of the tempo of the NDT in the Levant is discussed in terms of the impact on change in the fertility of residual forager mobility in the new farming system.

DEMOGRAPHIC AND HEALTH CHANGES DURING THE TRANSITION TO AGRICULTURE IN NORTH AMERICA

What were the consequences of Neolithic demographic transition on population’s health? The paradigmatic question asked by Mark Cohen 30 years ago is revisited: did biological stresses, which are indicators of a population’s well being, increase with the transition to agriculture? Data on four North American skeletal biological markers; dental caries (31 archeological sites), porotic hyperostosis (33 sites), cribra orbitalia (22 sites) and femur length sexual dimorphism (22 sites), used as proxy for stature; are set in the same chronological framework and related to the two-stage Neolithic demographic transition? How did they co-vary? Caries frequency increase one thousand years before the transition to agriculture. This pattern probably indicates the broadening of the diet range during the time before agriculture takes place as well as the addition of sugar in the diet. As soon as the transition to agriculture takes place, and fertility increases, the prevalence of anemia markers increases and stature sexual dimorphism decreases. Overall, the picture confirms the hypothesis of biological stresses, during the transition

Toward the adoption of cementochronology in forensic context

Because acellular dental cementum is considered to be formed continually throughout life and to not undergo remodeling processes, cementochronology is considered to be a method with the potential for directly assessing chronological age. Considering that most previous studies on humans have assumed the superior performance of this method, it is surprising that this technique is not more widely adopted in anthropology. To understand this controversy, we highlight that there is no standardized procedure for sample preparation. The numerous technical approaches that exist impact the reliability of the method, and the recent creation of an international work group (Cementochronology Research Program) demonstrates the need for researchers to share their experience to overcome these obstacles. This paper aims to address this paradox by debating the aspects that contribute to the limited use of this method and by illustrating its potential through an application on forensic cases. A protocol, which was recently certified according to the ISO-9001, was applied to nine anthropological cases from the Forensic Medicine Institute of Lille (northern France) and compared with routine osteological and dental methods. The results show that traditional methods matched the known age due to the wide extent of their range, while the accuracy and precision of cementochronological estimates was also notable. This paper establishes that cementochronology may serve as a particularly important tool for age estimation for forensic anthropologists and should, at least, be used in addition to other methods.

Specific Patterns of Canine Scavenging in Indoor Settings

Postmortem animal mutilations due to domestic dogs in isolated domestic deaths are taphonomic modifications regularly observed by forensic pathologists. They are rarely described in the literature; however, even though they present specific patterns. Through 41 cases, 10 at the forensic institute in Lille (France) and 31 at the New York City Office of Chief Medical Examiner (USA), plus 22 cases from the literature, specific locations and patterns of postmortem scavenging lesions are proposed. These lesions are mainly distributed in three locations: the face, especially the nose and the mouth (73.1%), the neck (43.1%), and the arm (shoulder/upper limb [29.2%], hand [26.8%]). We discuss the time span between death and scavenging, the consequences on identification, and comparison with outdoor settings. Outdoor scavenging lesions are mainly located on the trunk and limbs usually sparing the head, which strongly differs from indoor distribution and imply different animal motivations.

Testing the Hypothesis of a Worldwide Neolithic Demographic Transition

The signal of a major demographic change characterized by a relatively abrupt increase in the proportion of immature skeletons has been detected in a paleoanthropological database of 38 MesolithicNeolithic cemeteries from Europe and North Africa. From the Mesolithic to the Neolithic, the proportion of immature skeletons increases by 2030% over a period of 500700 years, indicating a notable increase in the crude birth rate. This shift has been called the Neolithic demographic transition. A similar signal has been detected in an independent set of archaeological data, namely, enclosures. This paper presents results from a sample of 62 cemeteries in North America (7,755 BP350 BP) that point to the same transition over a period of 600800 years.The signal of a major demographic change characterized by a relatively abrupt increase in the proportion of immature skeletons has been detected in a paleoanthropological database of 38 MesolithicNeolithic cemeteries from Europe and North Africa. From the Mesolithic to the Neolithic, the proportion of immature skeletons increases by 2030% over a period of 500700 years, indicating a notable increase in the crude birth rate. This shift has been called the Neolithic demographic transition. A similar signal has been detected in an independent set of archaeological data, namely, enclosures. This paper presents results from a sample of 62 cemeteries in North America (7,755 BP350 BP) that point to the same transition over a period of 600800 years.

New Insights on the Composition and the Structure of the Acellular Extrinsic Fiber Cementum by Raman Analysis

Acellular extrinsic fiber cementum is a mineralized tissue that covers the cervical half of the tooth root surface. It contains mainly extrinsic or Sharpey’s fibers that run perpendicular to the root surface to anchor the tooth via the periodontal ligament. Acellular cementum is continuously and slowly produced throughout life and exhibits an alternating bright and dark pattern under light microscopy. However, although a better understanding of the structural background of acellular cementum is relevant to many fields, such as cementochronology, periodontology and tissue engineering, acellular cementum remains rarely studied and poorly understood. In this work, we studied the acellular cementum at the incremental line scale of five human mandibular canines using polarized Raman spectroscopy. We provided Raman imaging analysis and polarized acquisitions as a function of the angular orientation of the sample. The results showed that mineral crystals were always parallel to collagen fibrils, and at a larger scale, we proposed an organizational model in which we found radial collagen fibers, “orthogonal” to the cementum surface, and “non-orthogonal” fibers, which consist of branching and bending radial fibers. Concerning the alternating pattern, we observed that the dark lines corresponded to smaller, more mineralized and probably more organized bands, which is consistent with the zoological assumption that incremental lines are produced during a winter rest period of acellular cementum growth.

Age-at-death estimation of pathological individuals: A complementary approach using teeth cementum annulations

Bioarchaeologists rely on accurate estimations of age-at-death. Clearly, some pathological conditions are associated with gross morphological changes in the skeleton that could impact the effectiveness of age-at-death estimation (i.e. methods based on the pelvis, fourth rib, dental attrition, and cranial stenosis). The magnitude of this problem has not been widely studied due to a paucity of pathological skeletons of known age. We assessed age-at death for three individuals affected by bone dysplasias (achondroplasia, residual rickets, osteogenesis imperfecta) using cementum annulations and several osseous age indicators. We predicted osseous indicators that are based on gross morphological changes would yield age estimates discrepant from the cementochronology. Results demonstrated considerable differences in age estimates between morphological and histological techniques suggesting a need for additional research on the effects of pathology on the accuracy of morphological methods. Conversely, we addressed the proposition that cementum annulations will be inappropriate for age estimation in cases of chronic and severe rhino-maxillary infection and periodontitis. We assessed age-at-death for one individual with leprosy and found no indication the disease process affected cementum formation or preservation. The results of this research indicate the potential value of cementochronology in cases where skeletal pathological conditions constrain the usefulness of traditional age estimation approaches.

The impact of periodontal disease on cementochronology age estimation

Estimating an individuals age at death is essential for post-mortem identification, paleopathology and paleodemography. With substantial development over the past 10 years in cementochronology analyses, some concerns have arisen that oral pathological conditions may artificially reduce or increase cementum apposition. The objective of this study was to observed the impact of periodontal disease on acellular cementum and on the reliability of cementochronology to test its accuracy for estimating individual age at death. The study included 41 teeth presenting different degrees of bone destruction, extracted from 18 individuals affected by untreated periodontal disease. The results demonstrated that the degree of alveolysis had only limited effects on the counting of cementum annulations in the middle (rp=0.92, p<0.01 between estimated and civil age) and the cervical (rp=0.85, p<0.01) thirds of the root, whereas in the apical third, the increments were affected considerably. This cementum reactive process compensates for bone destruction and loss of the attachment apparatus. These data suggest that cementum could continue to grow at a slower rate despite bone destruction due to periodontal disease. Cementochronology can thus be applied to teeth with a damaged periodontium by sectioning the middle third of the root.

Tuberculosis and survival in past populations: A paleo-epidemiological appraisal

Historical assessments of the last two centuries consistently placed tuberculosis as the leading cause of mortality. However, for earlier periods, we can only calculate the frequencies of archaeological bone lesions, which tell us little about the real impact of the disease on mortality. These lesions are usually observed in individuals who have developed immune resistance, which is visible as healed osteo-articular lesions. This study aimed to test the differential impacts of tuberculosis, cribra orbitalia and cribra femoris on adult survival and sex-based survival. We analyzed 28 French adult samples from the Antiquity and the Early Middle Ages. The age-at-death of 1480 individuals was estimated using cementochronology. Survival curves and median age-at-death were calculated to test new hypotheses that challenge the parasitic and deficiency theories of bone stress markers. Comparisons between carriers and non-carriers provided new information concerning the plausible causes of bone stress markers related to infections and TB. The most likely hypothesis is skeletal demineralization and osteoclastic resorption, which are usually observed close to tubercular granuloma or distant from active lesions. The bone marrow niche of Mycobacterium tuberculosis within CD271(+) BM-MSCs stem cells is the proposed explanation for the localized cortical resorption that is observed in bone stress markers.