Refining the Quadratic Crown Height Method of age estimation: do elk teeth wear quadratically with age?

Teeth are the basis for the best methods for estimating the age-at-death of archaeological and paleontological faunal remains, because they change by eruption and wear throughout an individual's life and because they preserve well. However, age-at-death can be difficult to estimate when teeth are isolated or when no known-age reference sample is available. For these reasons, researchers developed the Quadratic Crown Height Method (QCHM), a set of quadratic formulae that can be used to predict age-at-death from tooth crown height, when unworn crown height and the ages when the tooth erupts and when its crown height should reach zero can be estimated. Previous tests of the QCHM suggest that modified equations could improve the method. Here, we use crown height measurements on a sample of 226 known-age Rocky Mountain elk (Cervus elaphus) to perform such modifications. We adjust the age at which each tooth type's crown height reaches zero from the species' potential ecological longevity or average maximum life span to an age that we empirically estimate for each tooth type. We also empirically assess whether for different elk teeth the exponent in the QCHM formula is actually equal to 2; it is for M1, but for P4 it is about 1, indicating a roughly linear relationship. The exponents for M2 and M3 are intermediate, being closer to 1.5. Because different teeth wear at different rates and wear completely away at different ages, we recommend that researchers use the modified equations provided here to estimate age-at-death for samples of Cervus elaphus.     

Force-Based Beam Finite Element (FE) for the Pushover Analysis of Masonry Buildings

A simplified approach for analyzing the nonlinear response of masonry buildings, based on the equivalent frame modeling procedure and on the nonlinear equivalent static analyses, is presented. A nonlinear beam finite element (FE) is formulated in the framework of a force-based approach, where the stress fields are expanded along the beam local axis, and introduced in a global displacement-based FE code. In order to model the nonlinear constitutive response of the masonry material, the lumped hinge approach is adopted and both flexural and shear plastic hinges are located at the two end nodes of the beam. A classical elastic-plastic constitutive relationship describes the nonlinear response of the hinges, the evolution of the plastic variables being governed by the Kuhn-Tucker and consistency conditions. An efficient element state determination procedure is implemented, which condenses the local deformation residual into the global residual vector, thus avoiding the need to perform the inner loops for computing the element nonlinear response. The comparison with some relevant experimental and real full-scale masonry walls is presented, obtaining a very good agreement with the available results, both in terms of global pushover curves and damage distributions.     

Mortality curves for horses from the Middle Palaeolithic site of Bau de l'Aubesier (Vaucluse, France): methodological, palaeo-ethnological, and palaeo-ecological approaches

A new methodology for estimating the age of death of horse, based on the degree of hypsondonty, has been established using the dental material of Equus mosbachensis, Equus cf. taubachensis, and Equus sp., which were hunted from the Mousterian levels of the Bau de l'Aubesier at Monieux (Vaucluse, France). Our model is based on a regression analysis of curvilinear type, and allows the precise determination of age classes intervals and the distribution of estimated ages, by systematically taking into account the standard deviation. These estimates were tested from all the paired teeth of horses belonging to the same individuals, from the sites of Bau de l'Aubesier and of Jaurens at Nespouls (Corrèze, France).The age structures of the horses of Bau de l'Aubesier were compared in the different levels of the sequence with their frequencies, survival rates, and mortality rates corresponding to as many curves as often used in population ecology and demographics. The different age classes of a present-day natural African population (Equus burchelli boehmi), the individuals having died accidentally in the National Park of Akagera (Rwanda) following a bush fire, provide an interesting comparative catastrophic model with regard to the population dynamics, and permit us to evaluate the impact of Neandertals on the Equidae fossils of Bau de l'Aubesier. Our assemblage clearly indicates in the lower layers, a systematic selection of adult horses, as opposed to the upper sequence where juveniles and adults dominate. Ecological factors, such as seasonal migratory phenomena and herd gathering, which characterise many large size species are also tackled and could explain the high proportion of adults in French Middle Palaeolithic sites where horses were preferentially hunted.     

Culling profiles: the indeterminacy of archaeozoological data to survivorship curve modelling of sheep and goat herd maintenance strategies

The comparison of survivorship curves derived from seven different models aiming to reconstruct ancient sheep and goat herd maintenance strategies (e.g. optimization of wool, meat, and milk production) shows that many of these models cannot be distinguished statistically. This observation renders the current theoretical framework for reconstructing ancient herd maintenance strategies problematic, due to the possible indeterminacy of model data analysis. In order to assign empirically observed age-at-death data to a model of herd maintenance strategy, it is suggested that a direct fit of observed data to survivorship curves be forgone in favor of a binning procedure highlighting the differences between fewer and more distinguishable models. The incorporation of high-resolution sexing and taxonomic determination to coarse-grained age-at-death models may go a long way towards solving the current problem of indeterminacy.     

Comparing expeditious procedures for the seismic vulnerability assessment on the European territorial context: reliability,feasibility, cost,and time consumption

ABSTRACT

The definition of strategies for the preservation and protection of cultural heritage is a topical issue, especially in view of the increasing relevance of the theme of seismic risk mitigation and reduction.

The prediction of the impact an earthquake could have on existing buildings requires the knowledge of their dynamic behaviour. The procedure to be adopted for this purpose is quite complex and onerous in terms of costs, time, and implementation, especially when the study concerns territorial areas rather than single buildings. The definition of methodologies aimed at respecting the principles of economic sustainability and preserving human life and architectural heritage is of paramount importance to assess seismic vulnerability using available resources. Rapid methods for the seismic vulnerability assessment, aimed at defining buildings vulnerability and intervention priority lists, must be implemented to guarantee the preservation of historical centers.

This article describes the application to some case studies of different methods aimed at creating fragility curves for the vulnerability assessment on the European territorial context. The comparison between a deterministic approach and a new probabilistic one is performed for all case studies, to define the most suitable methodology in terms of reliability and savings in cost and time.     

Statistical tool for dating and interpreting archaeological contexts using pottery

Analyzing chronological patterns is one of the major issues in archaeology. How can the date of a specific context be estimated? Is it possible to identify residual and intrusive material in it at the same time? Numerous statistical methodological approaches have been developed and implemented to estimate dates but have less often addressed the issue of socio-economic area or the functional interpretation of contexts. This article deals with the construction and analysis of two different probability estimate density curves of context dates using pottery. By contrasting the two curves we can define the boundaries of the socio-economic area and make a chrono-functional interpretation of a context. This statistical tool allows the archaeologist to visualize and analyze chronological patterns easily. The method is applied to the analysis of contexts in the town of Tours in particular and more generally in the centre-west of France, based on collected pottery finds.     

The analysis of innovation processes

Methods are described for modelling both the speeds and the driving forces of innovation processes, namely Critical Path Schedules and Cash Flow Curves respectively. The differences between innovations in modern industrial conditions and simpler societies are discussed, and the models applied to early innovations, but the data are too fragmentary to make quantitative models, although they can be used qualitatively to show general trends. In early societies the speeds were very slow but benefit/cost ratios very high, whereas the reverse tends to be true on average for modern innovations. Long delay times are often found in early innovation processes and these are determined by a wide variety of cultural factors. Seldom has the progress of the technology itself been on the “Critical Path” of innovation processes. The “Critical Path” and “Cash Flow” methods can also be used to study other, non-innovative, complex processes.     

受控冷冻灭虫法的风险控制

受控冷冻灭虫的关键在受控,受控指标包括冷冻温度、降温速度与冷冻时间,受控的目的是要达到彻底灭虫。冷冻温度与降温速度直接影响到被冷冻物品的形体安全,保障物品安全为前提的受控冷冻灭虫需要管控风险。基于文献分析、相关问题的调研与理论研究发现,温度不够低、降温速度不够快以及灭虫时间过短都会造成灭虫不彻底的风险。极端低温与快速降温带来物品的损伤与被冷冻物品的材料性质相关,将在极端低温与热冲击力下必然会损坏的材料排除在冷冻灭虫的许可范围之外,科学地选择冷冻温度与加强冷冻灭虫过程管控,可使受控冷冻灭虫化险为夷,即以保证藏品安全为前提的彻底灭虫。