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Orkney was a major cultural center during the Neolithic, 3800 to 2500 BC. Farming flourished, permanent stone settlements and chambered tombs were constructed, and long-range contacts were sustained. From â¼3200 BC, the number, density, and extravagance of settlements increased, and new ceremonial monuments and ceramic styles, possibly originating in Orkney, spread across Britain and Ireland. By â¼2800 BC, this phenomenon was waning, although Neolithic traditions persisted to at least 2500 BC. Unlike elsewhere in Britain, there is little material evidence to suggest a Beaker presence, suggesting that Orkney may have developed along an insular trajectory during the second millennium BC. We tested this by comparing new genomic evidence from 22 Bronze Age and 3 Iron Age burials in northwest Orkney with Neolithic burials from across the archipelago. We identified signals of inward migration on a scale unsuspected from the archaeological record: As elsewhere in Bronze Age Britain, much of the population displayed significant genome-wide ancestry deriving ultimately from the Pontic-Caspian Steppe. However, uniquely in northern and central Europe, most of the male lineages were inherited from the local Neolithic. This suggests that some male descendants of Neolithic Orkney may have remained distinct well into the Bronze Age, although there are signs that this had dwindled by the Iron Age. Furthermore, although the majority of mitochondrial DNA lineages evidently arrived afresh with the Bronze Age, we also find evidence for continuity in the female line of descent from Mesolithic Britain into the Bronze Age and even to the present day.
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ADN Mitocondrial/genética , Migración Humana/historia , Herencia Paterna/genética , Arqueología , ADN Antiguo/análisis , Inglaterra , Europa (Continente) , Femenino , Fósiles , Pool de Genes , Genoma Humano/genética , Genómica , Haplotipos , Historia Antigua , Historia Medieval , Humanos , Irlanda , Masculino , EscociaRESUMEN
The COVID-19 pandemic has passed. It gives us a real-world example of kinetic data analysis practice for our undergraduate physical chemistry laboratory class. It is a great example to connect this seemingly very different problem to the kinetic theories for chemical reactions that the students have learned in the lecture class. At the beginning of the spring 2023 semester, we obtained COVID-19 kinetic data from the "Our World in Data" database, which summarizes the World Health Organization (WHO) data reported from different countries. We analyzed the effective spreading kinetics based on the susceptible-infectious-recovered-vaccinated (SIR-V) model. We then compared the effective rate constants represented by the real-time reproduction numbers ( R t ) underlining the reported data for these countries and discussed the results and the limitations of the model with the students.
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Family's socioeconomic profile collected prenatally is known to predict offspring mortality during early life, but it remains unclear whether it has the potential to predict offspring mortality until later life. In this study, 12,063 individuals belonging to the Northern Finland Birth Cohort 1966 were followed up from mid-pregnancy for 52 years (570,000 person years). Five distinct socioeconomic profiles were identified by latent class analysis based on mother's marital status, education, and occupation; father's occupation; number of family members; location of residence, room count, and utilities; and family's wealth. The classes were highest status families (15.4% of the population), small families (22.1%), larger families (15.4%), average wealth families (23.4%), and rural families (23.3%). Their associations to offspring mortality, via linkage to national offspring death records, were analysed by Cox regression, stratified by sex and age groups (0-19, 20-38 and 40-52 years). In total, mortality was 9.2% among male and 5.0% among female offspring. Risk for midlife mortality was higher among male offspring from larger families (hazard ratio 2.19, 95% confidence interval 1.32-3.63), average wealth families (1.66, 1.02-2.73) and rural families (1.63, 1.00-2.68), relative to offspring from highest status families. It seems that family's socioeconomic profile constructed prenatally has predictive value for midlife mortality among male offspring. Premature mortality of men and women seem to be two distinct phenomena with differing underlying factors as socioeconomic profile was not associated with mortality among female offspring.
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Cohorte de Nacimiento , Familia , Estudios de Cohortes , Escolaridad , Femenino , Finlandia/epidemiología , Humanos , Recién Nacido , Masculino , Embarazo , Factores SocioeconómicosRESUMEN
Ancient biomolecule analyses are proving increasingly useful in the study of evolutionary patterns, including extinct organisms. Proteomic sequencing techniques complement genomic approaches, having the potential to examine lineages further back in time than achievable using ancient DNA, given the less stringent preservation requirements. In this study, we demonstrate the ability to use collagen sequence analyses via proteomics to assist species delimitation as a foundation for informing evolutionary patterns. We uncover biogeographic information of an enigmatic and recently extinct lineage of Nesophontes across their range on the Caribbean islands. First, evolutionary relationships reconstructed from collagen sequences reaffirm the affinity of Nesophontes and Solenodon as sister taxa within Solenodonota. This relationship helps lay the foundation for testing geographical isolation hypotheses across islands within the Greater Antilles, including movement from Cuba toward Hispaniola. Second, our results are consistent with Cuba having just two species of Nesophontes (N. micrus and N. major) that exhibit intrapopulation morphological variation. Finally, analysis of the recently described species from the Cayman Islands (N. hemicingulus) indicates that it is a closer relative to N. major rather than N. micrus as previously speculated. This proteomic sequencing improves our understanding of the origin, evolution, and distribution of this extinct mammal lineage, particularly with respect to the approximate timing of speciation. Such knowledge is vital for this biodiversity hotspot, where the magnitude of recent extinctions may obscure true estimates of species richness in the past.
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Evolución Biológica , Colágeno/química , Musarañas/genética , Animales , Femenino , Masculino , Mandíbula/anatomía & histología , Filogeografía , Análisis de Secuencia de Proteína , Caracteres Sexuales , Musarañas/anatomía & histología , Indias OccidentalesRESUMEN
Proteomic analyses are becoming more widely used in archeology not only due to the greater preservation of proteins in ancient specimens than DNA but also because they can offer different information, particularly relating to compositional preservation and potentially a means to estimate biological and geological age. However, it remains unclear to what extent different burial environments impact these aspects of proteome decay. Teeth have to date been much less studied than bone but are ideal to explore how proteins decay with time due to the negligible turnover that occurs in dentine relative to bone. We investigated the proteome variability and deamidation levels of different sections of molar teeth from archeological bovine mandibles as well as their mandibular bone. We obtained a greater yield of proteins from the crown of the teeth but did not find differences between the different molars analyzed within each mandible. We also obtained the best variety of protein from a well-preserved mandible that was not the youngest one in terms of chronological age, showing the influence of the preservation conditions on the final proteomic outcome. Intriguingly, we also noticed an increase in abundance levels of fetuin-A in biologically younger mandibles as reported previously, but the opposite trend in tooth dentine. Interestingly, we observed higher glutamine deamidation levels in teeth from the geologically oldest mandible despite it being the biologically youngest specimen, showing that the archeological age strongly impacts on the level of deamidations observed, much more so than biological aging. This indicates that the glutamine deamidation ratio of selected peptides may act as a good predictor of the relative geochronological age of archeological specimens.
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Dentina/química , Mandíbula/química , Diente Molar/química , Preservación Biológica/historia , Proteoma/química , Proteómica/métodos , Secuencia de Aminoácidos , Animales , Arqueología , Bovinos , Ontología de Genes , Historia Antigua , Humanos , Espectrometría de Masas/instrumentación , Espectrometría de Masas/métodos , Anotación de Secuencia Molecular , Paleontología , Proteolisis , Proteoma/aislamiento & purificación , Proteómica/instrumentación , Factores de Tiempo , alfa-2-Glicoproteína-HS/historia , alfa-2-Glicoproteína-HS/aislamiento & purificaciónRESUMEN
Fossil body mass estimation is a well established practice within the field of physical anthropology. Previous studies have relied upon traditional allometric approaches, in which the relationship between one/several skeletal dimensions and body mass in a range of modern taxa is used in a predictive capacity. The lack of relatively complete skeletons has thus far limited the potential application of alternative mass estimation techniques, such as volumetric reconstruction, to fossil hominins. Yet across vertebrate paleontology more broadly, novel volumetric approaches are resulting in predicted values for fossil body mass very different to those estimated by traditional allometry. Here we present a new digital reconstruction of Australopithecus afarensis (A.L. 288-1; 'Lucy') and a convex hull-based volumetric estimate of body mass. The technique relies upon identifying a predictable relationship between the 'shrink-wrapped' volume of the skeleton and known body mass in a range of modern taxa, and subsequent application to an articulated model of the fossil taxa of interest. Our calibration dataset comprises whole body computed tomography (CT) scans of 15 species of modern primate. The resulting predictive model is characterized by a high correlation coefficient (r2 = 0.988) and a percentage standard error of 20%, and performs well when applied to modern individuals of known body mass. Application of the convex hull technique to A. afarensis results in a relatively low body mass estimate of 20.4 kg (95% prediction interval 13.5-30.9 kg). A sensitivity analysis on the articulation of the chest region highlights the sensitivity of our approach to the reconstruction of the trunk, and the incomplete nature of the preserved ribcage may explain the low values for predicted body mass here. We suggest that the heaviest of previous estimates would require the thorax to be expanded to an unlikely extent, yet this can only be properly tested when more complete fossils are available.
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Antropometría/métodos , Peso Corporal , Fósiles , Hominidae/fisiología , Animales , Antropología Física , Femenino , Masculino , PaleontologíaRESUMEN
Proteomic methods are acquiring greater importance in archaeology and palaeontology due to the longevity of proteins in skeletal remains. There are also developing interests in forensic applications, offering the potential to shed light on post-mortem intervals and age at death estimation. However, our understanding of intra- and interskeletal proteome variations is currently severely limited. Here, we evaluated the proteomes obtained from five distinct subsamples of different skeletal elements from buried pig carcasses to ascertain the extent of variation within and between individuals. We found that reproducibility of data depends on the skeletal element used for sampling and that intrabone differences exceed those observed between the same skeletal element sampled from different individuals. Interestingly, the abundance of several serum proteins appeared to correlate with biological age with relative concentrations of alpha-1 antitrypsin and chromogranin-A increasing and those of fetuin-A decreasing. We also observed a surprising level of divergence in data from different LC-MS/MS runs on aliquots of similar samples analyzed months apart, adding constraints to the comparison of results of such methods across different studies.
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Huesos/química , Proteoma/análisis , Proteómica/métodos , Animales , Cambios Post Mortem , Reproducibilidad de los Resultados , Esqueleto/química , Porcinos , Espectrometría de Masas en TándemRESUMEN
RATIONALE: Microfaunal skeletal remains can be sensitive indicators of the contemporary ecosystem in which they are sampled and are often recovered in owl pellets in large numbers. Species identification of these remains can be obtained using a range of morphological criteria established for particular skeletal elements, but typically dominated by a reliance on cranial characters. However, this can induce biases under different environmental and taphonomic conditions. The aim of this research was to develop a high-throughput method of objectively identifying rodent remains from archaeological deposits using collagen fingerprinting, most notably the identification of rats from other myomorph rodents as a means to identify disturbances in the archaeofauna through the presence of invasive taxa not contemporary with the archaeological deposits. METHODS: Collagen was extracted from complete microfaunal skeletal remains in such a manner as to leave the bones morphologically intact (i.e., weaker concentration of acid than previously used over shorter length of time). Acid-soluble collagen was then ultrafiltered into ammonium bicarbonate and digested with trypsin prior to dilution in the MALDI matrix and acquisition of peptide mass fingerprints using a matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometer. RESULTS: Collagen fingerprinting was able to distinguish between Rattus, Mus, Apodemus and Micromys at the genus level; at the species level, R. rattus and R. norvegicus could be separated whereas A. flavicollis and A. sylvaticus could not. A total of 12,317 archaeological microvertebrate samples were screened for myomorph signatures but none were found to be invasive rats (Rattus) or mice (Mus). Of the contemporary murine fauna, no harvest mice (Micromys) were identified and only 24 field mouse (Apodemus) discovered. CONCLUSIONS: As a result, no evidence of recent bioturbation could be inferred from the faunal remains of these archaeological deposits. More importantly this work presents a method for high-throughput screening of specific taxa and is the first application of collagen fingerprinting to microfaunal remains of archaeological specimens.
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Milk from domestic cows has been a valuable food source for over 8,000 years, especially in lactose-tolerant human societies that exploit dairy breeds. We studied geographic patterns of variation in genes encoding the six most important milk proteins in 70 native European cattle breeds. We found substantial geographic coincidence between high diversity in cattle milk genes, locations of the European Neolithic cattle farming sites (>5,000 years ago) and present-day lactose tolerance in Europeans. This suggests a gene-culture coevolution between cattle and humans.
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Bovinos/genética , Evolución Molecular , Variación Genética , Lactasa/genética , Proteínas de la Leche/genética , Animales , Europa (Continente) , Femenino , Geografía , Humanos , Lactasa/metabolismo , Intolerancia a la Lactosa , Leche , Proteínas de la Leche/metabolismo , Densidad de PoblaciónRESUMEN
The growth and development of long bones are of considerable interests in the fields of comparative anatomy and palaeoanthropology, as evolutionary changes and adaptations to specific physical activity patterns are expected to be revealed during bone ontogeny. Traditionally, the cross-sectional geometry of long bones has been examined at discrete locations usually placed at set intervals or fixed percentage distances along the midline axis of the bone shaft. More recently, the technique of morphometric mapping has enabled the continuous analysis of shape variation along the shaft. Here we extend this technique to the full sequence of late fetal and postnatal development of the humeral shaft in a modern human population sample, with the aim of establishing the shape changes during growth and their relationship with the development of the arm musculature and activity patterns. A sample of modern human humeri from individuals of age ranging from 24 weeks in utero to 18 years was imaged using microtomography at multiple resolutions and custom Matlab scripts. Standard biomechanical properties, cortical thickness, surface curvature, and pseudo-landmarks were extracted along radial vectors spaced at intervals of 1° at each 0.5% longitudinal increment measured along the shaft axis. Heat maps were also generated for cortical thickness and surface curvature. The results demonstrate that a whole bone approach to analysis of cross-sectional geometry is more desirable where possible, as there is a continuous pattern of variation along the shaft. It is also possible to discriminate very young individuals and adolescents from other groups by relative cortical thickness, and also by periosteal surface curvature.
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Húmero , Adolescente , Humanos , Anatomía Comparada , Ejercicio FísicoRESUMEN
The study of anatomy in England during the 18th and 19th century has become infamous for bodysnatching from graveyards to provide a sufficient supply of cadavers. However, recent discoveries have improved our understanding of how and why anatomy was studied during the enlightenment, and allow us to see the context in which dissection of the human body took place. Excavations of infirmary burial grounds and medical school cemeteries, study of hospital archives, and analysis of the content of surviving anatomical collections in medical museums enables us to re-evaluate the field from a fresh perspective. The pathway from a death in poverty, sale of the corpse to body dealer, dissection by anatomist or medical student, and either the disposal and burial of the remains or preservation of teaching specimens that survive today in medical museums is a complex and fascinating one.
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Anatomía/historia , Anatomía/educación , Cadáver , Disección , Educación Médica/historia , Inglaterra , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , HumanosRESUMEN
The evolutionary relationships of extant great apes and humans have been largely resolved by molecular studies, yet morphology-based phylogenetic analyses continue to provide conflicting results. In order to further investigate this discrepancy we present bootstrap clade support of morphological data based on two quantitative datasets, one dataset consisting of linear measurements of the whole skull from 5 hominoid genera and the second dataset consisting of 3D landmark data from the temporal bone of 5 hominoid genera, including 11 sub-species. Using similar protocols for both datasets, we were able to 1) compare distance-based phylogenetic methods to cladistic parsimony of quantitative data converted into discrete character states, 2) vary outgroup choice to observe its effect on phylogenetic inference, and 3) analyse male and female data separately to observe the effect of sexual dimorphism on phylogenies. Phylogenetic analysis was sensitive to methodological decisions, particularly outgroup selection, where designation of Pongo as an outgroup and removal of Hylobates resulted in greater congruence with the proposed molecular phylogeny. The performance of distance-based methods also justifies their use in phylogenetic analysis of morphological data. It is clear from our analyses that hominoid phylogenetics ought not to be used as an example of conflict between the morphological and molecular, but as an example of how outgroup and methodological choices can affect the outcome of phylogenetic analysis.
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Cefalometría , Hominidae/anatomía & histología , Cráneo/anatomía & histología , Diente/anatomía & histología , Animales , Análisis por Conglomerados , Bases de Datos Factuales , Femenino , Hominidae/fisiología , Humanos , Masculino , Filogenia , Cráneo/fisiología , Diente/fisiologíaRESUMEN
A principle of demographic uniformitarianism underpins all research into prehistoric demography (palaeodemography). This principle-which argues for continuity in the evolved mechanisms underlying modern human demographic processes and their response to environmental stimuli between past and present-provides the cross-disciplinary basis for palaeodemographic reconstruction and analysis. Prompted by the recent growth and interest in the field of prehistoric demography, this paper reviews the principle of demographic uniformitarianism, evaluates how it relates to two key debates in palaeodemographic research and seeks to delimit its range of applicability to past human and hominin populations. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.
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Arqueología , Demografía , Dinámica Poblacional , HumanosRESUMEN
Online reviews are widely used to propagate the reputations of employers. However, existing research suggests that online reviews often suffer from selection bias-people with extreme opinions are more motivated to select into sharing them than people with moderate opinions, resulting in more extreme ratings. We find that providing incentives for reviewing can reduce this selection bias, because incentives can mitigate the motivational deficit of people who hold moderate opinions. Using data from Glassdoor, a leading employer review website, we find that incentivized ratings are less extreme than voluntary (self-selected) ratings. The likely bias in the distribution of voluntary reviews can affect workers' choice of employers. We complement our investigation with a randomized experiment that provides a cleaner test of selection bias. We again find that voluntary reviews of employers lead to more extreme reviews compared to non-voluntary reviews. Moreover, providing relatively high monetary rewards or a pro-social cue as incentives for reviewing also lowers the relative prevalence of extreme reviews. Although voluntary employer reviews often suffer from selection bias, incentives can reduce it and help workers make more informed employment choices. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Motivación , Recompensa , Sesgo , HumanosRESUMEN
Age at death estimation methods, when applied to skeletal remains of adults, have provided inaccurate results. These aging methods often depend on observations of the degenerative changes occurring at specific articulations, however, the effects of the aging process on the human skeleton are only partially known. Therefore a need exists to increase our understanding about the age related metamorphosis process to improve aging methods. The aim of this study is to determine which age-related traits observable on the pelvic bone articulations are correlated and to quantify their shared degenerative variance. Thus it is intended to quantify the degenerative relationship among features within each pelvic joint. Fifteen age related traits were analyzed for the pubic symphysis, eight traits for the auricular surface of the ilium, and six traits for the acetabulum. Age-related traits from the pelvic joints were recorded on adult skeletons from two reference collections the William Bass Donated Skeletal Collection and the Coimbra Collection. A Principal Components Analysis, partial correlation controlling for age, and a Kendall's W coefficient of concordance were calculated to determine the level of dependence among traits. A similar pattern of correlation amongst traits was obtained for both collections. Some of the traits shared a high to moderate correlation. However, some features, such as dense bone at the auricular surface, possessed a high independence from other traits. Results suggest that age estimation methods should take into consideration how age-related traits correlate and their level of dependence, which may possibly assist in the establishment of more effective scoring systems in new and revised age at death estimation methods.
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Determinación de la Edad por el Esqueleto , Huesos Pélvicos , Sínfisis Pubiana , Adulto , Envejecimiento , Antropología Forense , Humanos , Huesos Pélvicos/anatomía & histología , Pelvis , Sínfisis Pubiana/anatomía & histologíaRESUMEN
BACKGROUND: In the absence of effective treatments or vaccines, non-pharmaceutical interventions are the mainstay of control in the COVID-19 pandemic. Refugee populations in displacement camps live under adverse conditions that are likely to favour the spread of disease. To date, only a few cases of COVID-19 have appeared in refugee camps, and whether feasible non-pharmaceutical interventions can prevent the spread of the SARS-CoV-2 virus in such settings remains untested. METHODS: We constructed the first spatially explicit agent-based model of a COVID-19 outbreak in a refugee camp, and applied it to evaluate feasible non-pharmaceutical interventions. We parameterised the model using published data on the transmission rates and progression dynamics of COVID-19, and demographic and spatial data from Europe's largest refugee camp, the Moria displacement camp on Lesbos, Greece. We simulated COVID-19 epidemics with and without four feasible interventions. RESULTS: Spatial subdivision of the camp ('sectoring') was able to 'flatten the curve', reducing peak infection by up to 70% and delaying peak infection by up to several months. The use of face masks coupled with the efficient isolation of infected individuals reduced the overall incidence of infection, and sometimes averted epidemics altogether. These interventions must be implemented quickly in order to be maximally effective. Lockdowns had only small effects on COVID-19 dynamics. CONCLUSIONS: Agent-based models are powerful tools for forecasting the spread of disease in spatially structured and heterogeneous populations. Our findings suggest that feasible interventions can slow the spread of COVID-19 in a refugee camp setting, and provide an evidence base for camp managers planning intervention strategies. Our model can be modified to study other closed populations at risk from COVID-19 or future epidemics.
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COVID-19/prevención & control , Brotes de Enfermedades/prevención & control , Campos de Refugiados , COVID-19/epidemiología , COVID-19/transmisión , Grecia/epidemiología , Humanos , Modelos Teóricos , Factores de Riesgo , SARS-CoV-2RESUMEN
Inferring the locomotor behaviour of the last common ancestor (LCA) of humans and African apes is still a divisive issue. An African great-ape-like ancestor using knuckle-walking is still the most parsimonious hypothesis for the LCA, despite diverse conflicting lines of evidence. Crucial to this hypothesis is the role of the centrale in the hominoid wrist, since the fusion of this bone with the scaphoid is among the clearest morphological synapomorphies of African apes and hominins. However, the exact functional significance of this fusion remains unclear. We address this question by carrying out finite element simulations of the hominoid wrist during knuckle-walking by virtually generating fused and unfused morphologies in a sample of hominoids. Finite element analysis was applied to test the hypothesis that a fused scaphoid-centrale better withstands the loads derived from knuckle-walking. The results show that fused morphologies display lower stress values, hence supporting a biomechanical explanation for the fusion as a functional adaptation for knuckle-walking. This functional interpretation for the fusion contrasts with the current inferred positional behaviour of the earliest hominins, thus suggesting that this morphology was probably retained from an LCA that exhibited knuckle-walking as part of its locomotor repertoire and that was probably later exapted for other functions.
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Evolución Biológica , Articulación Metacarpofalángica/fisiología , Hueso Escafoides/fisiología , Caminata/fisiología , Animales , Hominidae , HumanosRESUMEN
Decomposition of animal bodies in the burial environment plays a key role in the biochemistry of the soil, altering the balance of the local microbial populations present before the introduction of the carcass. Despite the growing number of studies on decomposition and soil bacterial populations, less is known on its effects on fungal communities. Shifts in the fungal populations at different post-mortem intervals (PMIs) could provide insights for PMI estimation and clarify the role that specific fungal taxa have at specific decomposition stages. In this study, we buried pig carcasses over a period of 1- to 6-months, and we sampled the soil in contact with each carcass at different PMIs. We performed metabarcoding analysis of the mycobiome targeting both the internal transcribed spacer (ITS) 1 and 2, to elucidate which one was more suitable for this purpose. Our results showed a decrease in the fungal taxonomic richness associated with increasing PMIs, and the alteration of the soil fungal signature even after 6 months post-burial, showing the inability of soil communities to restore their original composition within this timeframe. The results highlighted taxonomic trends associated with specific PMIs, such as the increase of the Mortierellomycota after 4- and 6-months and of Ascomycota particularly after 2 months, and the decrease of Basidiomycota from the first to the last time point. We have found a limited number of taxa specifically associated with the carrion and not present in the control soil, showing that the major contributors to the recorded changes are originated from the soil and were not introduced by the carrion. As this is the first study conducted on burial graves, it sets the baseline for additional studies to investigate the role of fungal communities on prolonged decomposition periods and to identify fungal biomarkers to improve the accuracy of PMI prediction for forensic applications.
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Archaeological demography investigates the structure and dynamics of past human populations using evidence from traces of human activities and remnants of material culture in the archaeological record. Research in this field is interdisciplinary, incorporating findings from anthropology, paleogenetics, and human ecology but with a remit that extends beyond the primarily biological focus of paleodemography. Important questions addressed by archaeological demography include the establishment of methods for inferring past population structure, the timing of the emergence of modern human demographic systems, the relative importance of attritional and catastrophic patterns of mortality, and the search for adaptive explanations for demographic transitions, colonization events, and population extinctions. Archaeological evidence, including the extent of settlements and site catchment areas as well as measures of the exploitation, consumption, and discard of materials and artifacts, have traditionally been used as proxies for estimating past population size and density. In recent years this evidence has been supplemented by increasingly large data sets compiled from radiocarbon dating programs. These data sets have been used to investigate demographic waves of advance during continental-scale periods of colonization and cultural change and to detect episodes of population decline, extinction, and hiatuses in settlement history. By considering studies of human genetic diversity that indicate temporary but drastic reductions in effective population size, I hypothesize that catastrophic mortality may have had an important role in long-term population processes and may have limited long-term rates of growth, particularly in prehistoric populations.
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Arqueología , Densidad de Población , Demografía , Ecología , Fertilidad , Humanos , Crecimiento Demográfico , Factores de TiempoRESUMEN
The timing of skeletal maturation is one of the common indicators used to estimate age at death of juvenile skeletal remains. Skeletal maturation of the sternum has received less attention than other anatomical locations, and there is a general lack of detailed information about the fusion timing in the dry sternum that can be used for the estimation of age. The objective of this study is to document the age variation in the fusion of the body sternebrae, and both clavicular and intercostal notches. A three stage scale scheme was used (unfused elements, partial, and complete fusion) to quantify fusion of primary and secondary ossification centres in a sample of 68 individuals of both sexes from the identified skeletal collection housed at the National Museum of Natural History and Science in Lisbon, Portugal. Analysis was performed only for the pooled sex sample due to small sample size. Wide age intervals were obtained for fusion stages at all of the sternal centres. Primary ossification centres start to fuse between 1 and 27 years of age, with sternebrae 3 and 4 completing their fusion first. Secondary ossification centres fuse between 5 to 25 years of age. Results reflect considerable variability among individuals in the maturation of the sternum.