Age estimation from stages of epiphyseal union in the presacral vertebrae

The presacral vertebrae have various secondary centers of ossification, whose timing of fusion can be used for age estimation of human skeletal remains up to the middle to the latter third decade. However, detailed information about the age at which these secondary centers of ossification fuse has been lacking. In this study, the timing of epiphyseal union in presacral vertebrae was studied in a sample of modern Portuguese skeletons (57 females and 47 males) between the ages of 9 and 30, taken from the Lisbon documented skeletal collection. A detailed photographic record of these epiphyses and the age ranges for the different stages of epiphyseal union are provided. Partial union of epiphyses was observed from 11 to 27 years of age. In general, centers of ossification begin to fuse first in the cervical and lumbar vertebrae, followed by centers of ossification in the thoracic region. The first center of ossification to complete fusion is usually that of the mammillary process in lumbar vertebrae. This is usually followed by that of the transverse process, spinous transverse process, and annular ring, regardless of vertebra type. There were no statistically significant sex differences in timing of fusion, but there was a trend toward early maturation in females for some vertebra or epiphyses. Bilateral epiphyses did not show statistically significant differences in timing of fusion. This study offers information on timing of fusion of diverse epiphyseal locations useful for age estimation of complete or fragmented human skeletal remains. Am J Phys Anthropol, 2011. © 2010 Wiley‐Liss, Inc.     

Age estimation of zebra

A method of zebra age determination, using the decreasing height of Ml in a wear model, was compared with the method of visual assessment of incisor changes as used by Klingel & Klingel (1966). Good agreement between the methods was found.     

Age estimation from stages of union of the vertebral epiphyses of the ribs

This study attempts to fill a persistent gap in the literature by documenting the timing of epiphyseal union at the vertebral end of the ribs in a sample of modern Portuguese skeletons. The skeletal remains of 53 females and 45 males, between the ages of 11 and 30, were taken from the Lisbon documented skeletal collection. Individuals in the sample have been previously described as being representative of a middle‐to‐low socioeconomic segment of the early 20th century Lisbon population. Three anatomical locations were examined for epiphyseal union: the head, the articular tubercle and the nonarticular tubercle. The first epiphysis to show partial union is that of the nonarticular tubercle (females, 11–19 years; males, 11–19 years), followed by the epiphysis of the articular tubercle (females, 11–20 years; males, 16–20 years), and finally by the head epiphysis (females, 15–24 years; males, 16–22 years), which can still show incomplete epiphyseal closure at 25 and 24 years for females and males, respectively. A trend for earlier female maturation was observed, but the statistical tests only confirmed this result for some ribs and age groups. No directional asymmetry was found, but a significant fluctuating asymmetry was observed in all three epiphyses. A preliminary analysis showed that the asymmetric group of individuals in the study sample includes all the rural‐to‐urban migrants, relative to the symmetric group. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.     

Age estimation from the auricular surface of the ilium: a revised method

A revised method for estimating adult age at death using the auricular surface of the ilium has been developed. It is based on the existing auricular surface aging method of Lovejoy et al. ([1985] Am. J. Phys. Anthropol. 68:15-28), but the revised technique is easier to apply, and has low levels of inter- and intraobserver error. The new method records age-related stages for different features of the auricular surface, which are then combined to provide a composite score from which an estimate of age at death is obtained. Blind tests of the method were carried out on a known-age skeletal collection from Christ Church, Spitalfields, London. These tests showed that the dispersion of age at death for a given morphological stage was large, particularly after the first decade of adult life. Statistical analysis showed that the age-related changes in auricular surface are not significantly different for males and females. The scores from the revised method have a slightly higher correlation with age than do the Suchey-Brooks pubic symphysis stages. Considering the higher survival rates of the auricular surface compared with the pubic symphysis, this method promises to be useful for biological anthropology and forensic science.     

The estimation of Wright's fixation index from genotypic frequencies

For populations in which the genotypic frequencies are estimated, it is customary to test the deviation of the estimates from those predicted by the Hardy-Weinberg Law using the x² goodness-of-fit statistic. Maximum likelihood estimation ofWright's F statistic and its variance furnishes a similar test. Following the derivation of the variance of , this note reviews the relation between the two tests. The F statistic possesses the advantages of full sufficiency and an easier formulation of the power function. Its bias is negligible when sample size exceeds 20.     

Age estimation in subadult Egyptian remains

In anthropological analyses of past populations, it is very important to be able to accurately reconstruct the palaeodemographic profile in order to interpret infant mortality as an indicator of the environmental, social and cultural conditions. There are various methods to evaluate the age of immature individuals but some of these methods are strongly influenced by the different rates of skeletal development observed in populations from various geographical areas and/or from various time periods, as well as between the sexes. Clearly, there is a need for adopting a method of estimation of age at death, which will be the one most suitable for analysing the particular skeletal sample.In this study we investigated subadults from the Egyptian osteological collection housed in the Museum of Anthropology and Ethnography of the University of Turin. For each individual, the age at death was estimated based on the degree of eruption and mineralisation of the teeth. Then the estimated age at death was correlated with the measurements of the long bones and ilium.We showed that greater regularity and constancy of rates of skeletal growth could be assessed with measurements, alternative to using maximum length of diaphysis. Moreover, using alternative characters, it was possible to markedly increase the number of individuals whose age at death could be estimated. Our study also showed the need to use a reference sample consistent with the sample being analysed and, which was derived from similar biological-environmental context. Therefore, our proposed method can be used for the estimation of age at death in pre/protohistorical populations from the Mediterranean region.     

Age related patterns of immunoglobulin serum levels in the Quechua Indians of Andean Mountains

Age-dependent changes of IgA, IgG, IgM, and IgD serum levels in a population of Quechua Indians of Peruvian Andes at 4 300 m were investigated. A first increase and a subsequent decrease in IgA and IgM levels were observed with advancing age. IgG and IgD only display an increase during development. More or less pronounced sex-related changes were also found in all Ig classes, the sex dependent pattern of IgA being the more evident one. It has been suggested that sexual, genetic and environmental influences strongly superimpose to high altitude related changes in Ig profile during ageing.     

Palaeopathology of human remains from the Roman Imperial Age

The increasing attention of archaeological and anthropological research towards palaeopathological studies has allowed to focus the examination of many skeletal samples on this aspect and to evaluate the presence of many diseases afflicting ancient populations. This paper describes the most interesting diseases observed in skeletal samples from five necropolises found in urban and suburban areas of Rome during archaeological excavations in the last decades, and dating back to the Imperial Age. The diseases observed were grouped into the following categories: articular diseases, traumas, infections, metabolic or nutritional diseases, congenital diseases and tumors, and some examples are reported for each group. Although extensive epidemiological investigation in ancient skeletal records is impossible, palaeopathology allowed highlighting the spread of numerous illnesses, many of which can be related to the life and health conditions of the Roman population.     

An estimation of the absolute number of axons indicates that human cortical areas are sparsely connected

The tracts between cortical areas are conceived as playing a central role in cortical information processing, but their actual numbers have never been determined in humans. Here, we estimate the absolute number of axons linking cortical areas from a whole-cortex diffusion MRI (dMRI) connectome, calibrated using the histologically measured callosal fiber density. Median connectivity is estimated as approximately 6,200 axons between cortical areas within hemisphere and approximately 1,300 axons interhemispherically, with axons connecting functionally related areas surprisingly sparse. For example, we estimate that <5% of the axons in the trunk of the arcuate and superior longitudinal fasciculi connect Wernicke’s and Broca’s areas. These results suggest that detailed information is transmitted between cortical areas either via linkage of the dense local connections or via rare, extraordinarily privileged long-range connections.

Using data from Human Connectome Project to estimate the absolute number of axons linking cortical areas yields surprisingly sparse connectivity; reconciling large-scale functional synchronization with sparse anatomical connectivity presents a challenge for our present understanding of human brain organization.     

Variance-component estimation from human sibship data

The large-sample relative efficiencies of the analysis-of-variance (ANOVA) estimators of variance components and the intraclass correlation coefficient rho are investigated for the unbalanced single classification in the context of family studies. The efficiency of an analysis based on the method of unweighted group means is also investigated. From a Monte Carlo study which generates the group sizes from typical family-size distributions it is found that the relative efficiency of the ANOVA estimators of the between-group variance component exceeds 95% for values of .2 less than or equal to rho less than or equal to .4, but can fall below 60% for values of rho that are very close to zero. For the estimation of the between-group variance component the method of unweighted means tends to be preferable to the ANOVA method only if rho greater than .5.     

Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida, with comments on clinal variation

Age and growth rates of the bonnethead shark, Sphyrna tiburo, from northwest Florida were estimated from vertebrae collected between October 1992 and October 1995. The von Bertalanffy growth equation was fit to male and female vertebral age data. Initial growth was rapid (≈ 200 mm TL) for both sexes from age 0–1. At age 2 growth slowed for males but continued for females. Similar to many species of sharks, females grew slower than males (K = 0.28 and K = 0.69, respectively) but attained a larger maximum size (L_∞=1226 and L_∞=897). Maximum age was estimated in males and females to be 8+ and 12+ years, respectively. Growth of young-of-year sharks was 21 to 30 mm TL per month determined by three different methods. A comparison of age and growth estimates from populations at more southerly latitudes suggest that clinal variation in total length may be evident among bonnethead sharks in the Gulf of Mexico with females reaching larger sizes in northern areas as compared to south Florida. This revised version was published online in July 2006 with corrections to the Cover Date.     

Age estimation, growth, maturity and distribution of the roundnose grenadier from the Rockall trough

This paper summarizes the history of commercial exploitation of roundnose grenadier Coryphaenoides rupestris in the North Atlantic. Length frequencies of C. rupestris in 1993, from 400 to 1200 m on the slopes of the Rockall trough indicate a reduction since the 1970s in the modal length of fish found at 700–1000 m. Ages ranged from 2 to 50 years for males and 2 to 60 years for females, with most between 10–38 years. Females attained a greater asymptotic pre-anus length ( L _∞=19.5 cm) than males ( L _∞=15.5 cm) and had a greater weight for a given age (male W _∞=761g, female W _∞=1132g). This species may have a protracted spawning period. Using pre-anus lengths, 50% of male fish were mature at 10 cm (ages 8–10) while 50% of female fish were mature at 12 cm (ages 9–11). At the greatest depths sampled the length frequency of fish was bimodal with a hiatus between 9 and 11 cm (ages 8–12). Highest catch rates occurred on the Donegal slope in September at a depth of 800–1000 m.