Differences between NISP and MNE in cutmark analysis of highly fragmented faunal assemblages

Documentation of cutmarks is standard protocol in contemporary zooarchaeology. However, there is currently no consensus about how to best quantify them. This study examines differences in cutmark patterning using two approaches: 1) by means of an experiment, comparing a control cutmark pattern to ten simulated highly fragmented sets of front and rear limbs using %NISPcut as the quantitative unit, and 2) by quantifying an archaeological faunal assemblage using both the number of identifiable specimens (NISP) and the comprehensive minimum number of elements (cMNE). Results reveal significant differences in cutmark patterning between the control set and the simulated fragmented sets. Additionally, the ordinal-scale frequencies of cutmark anatomical portions (proximal, shaft, distal) are inconsistent and fluctuate across the simulated sets. Results of the zooarchaeological analysis show that differences between the two quantification methods are significant. In general, this study suggests that on heavily fragmented assemblages, interpretations of butchering behavior based on cutmark patterning are influenced by the chosen unit of quantification. Overall, using NISP as the quantitative unit provides inconsistent results, whereas, by alleviating the effects of high fragmentation, cMNE is more reliable.     

How should permeability be measured in fine‐grained lithologies? Evidence from the chalk

Two chalk data sets from the Central North Sea (UK/Norway and Denmark) with a similar lithological classification and porosity values (5–20%) have a difference in permeability of up to three orders of magnitude. The method of measuring permeability was different for the two data sets: samples from UK/Norway were measured by transient pulse decay (TPD), while the Danish samples were measured by routine core analysis. Petrological and petrophysical characterization of samples from the two data sets have revealed that all samples display a similar range of rock properties; the differences are not due to regional facies variations. It is likely that the low permeability values reported by TPD have more validity than routine core analyses in measuring lower porosity and permeability chalk (5–20% porosity, <0.01 mD). The fact that large sections of North Sea chalk potentially have much lower permeability than previously reported has widespread implications for petroleum migration and entrapment, and overpressure generation.     

South American camelid bone structural density: what are we measuring? Comments on data sets,values, their interpretation and application

Bone mineral data are used in archaeology to evaluate density mediated attrition or differential preservation of archaeofaunas. For South American camelids, there are different data sets of bone mineral content. To evaluate their utility, these data sets were applied to the analysis of density mediated destruction of five archaeofaunal assemblages from Formative Period archaeological sites in the southern Calchaquíes valleys (Catamarca, Argentina) in order to evaluate interpretations achieved as an ‘end user’. Both inter- and intra-bone element density related survivorship analyses are made, concluding that for fine grain studies more complete data sets and specific analysis are required.     

Calibration and Test of a Discrete Choice Model with Endogenous Choice Sets

Conventional discrete choice models assume implicitly that the choice set is independent of the decisionmaker's preferences conditional on the explanatory variables of the models. This assumption is implausible in many choice situations where the decisionmaker selects his or her choice set. This paper estimates and tests a discrete choice model with endogenous choice sets based on Horowitz' theoretical work. To calibrate the model, a new probability simulator is introduced and a sequential estimation procedure is developed. The model and calibration methods are tested in an empirical application as well as Monte Carlo simulations. The empirical results are used to test the theory of endogenous choice sets and to examine the differences between the new model and a conventional choice model in parameter estimates and predicted choice probabilities. The empirical results strongly suggest that ignoring the endogeneity of choice sets in choice modeling can have serious consequences in applications.     

“Seek and you Shall Find.” How the Analysis of Gendered Patterns in Archaeology can Create False Binaries: a Case Study from Durankulak

The gender structures of the communities of the Late Neolithic and Copper Age in South East Europe have been firmly placed in a binary system by past archaeological analysis. The analysis of cemetery remains has indicated that binaries are expressed through differences in body position and the types of artefacts placed in the grave. However, re-evaluation of evidence from Durankulak cemetery on the Bulgarian Black Sea coast demonstrates that such interpretations may result from the imposition of a modern Western understanding of gender as binary based on sex; these assumptions can lead to the exclusion of data which points to more complex and varied gender relationships. This paper briefly discusses the problems in starting archaeological analyses from an assumed binary in both sex and gender. It is argued that any approach that starts with this binary is likely to be misleading, and that large-scale data sets, such as cemeteries, should be investigated using multivariate statistical techniques to uncover a variety of horizontal and vertical social categories and roles, of which gender may be a part. It demonstrates that in the case of Durankulak, while there are gender differences, there was a great deal of more complexity than a simple male/female division. Some artefacts are exclusively associated with male burials, while female graves have less variety in their assemblages.     

Legacy databases and GIS: a discussion of the issues illustrated by a case study of archaeological site data from southeast Alberta,Canada

Many institutions and agencies are currently faced with the issue of geographic information systems‐enabling legacy databases. The problems can be acute for data sets that have been compiled through many years, using different standards and levels of recording. To explore these issues further, we report on a data quality assessment undertaken in 2002 for a subset of the archaeological site database of the province of Alberta, Canada. Our work shows that positional ambiguities in the data set can be highlighted and corrected by relatively straightforward procedures. This case study also provides an indication of the amount of work effort that will be involved in validating or ‘cleaning up’ data sets so model results and analyses undertaken with them are more reliable.     

Bone density studies in zooarchaeology

Accurate bone density data are essential for assessing the influence of destructive processes in archaeological faunal assemblages. Unfortunately, the diversity of methods employed by different researchers to derive density values has resulted in recent confusion. Two recent publications in this journal [J Archaeol Sci 29 (2002) 883; J Archaeol Sci 29 (2002) 979] exemplify this state of misunderstanding. Both studies argued that the role of bone density in shaping archaeological faunal assemblages has been largely overrated, but both based their conclusions on density values that were inaccurately derived. The former employed a method of calculating bone density that has been largely discredited over the past decade [J Archaeol Sci 29 (2002) 883]. Within a larger discussion of zooarchaeological methodology, the latter provided an assessment of the current state of bone density research that inappropriately characterized the discrepancies between available sets of density data as a reflection of the differences between two technologies—photon densitometry and computed tomography [J Archaeol Sci 29 (2002) 979]. The actual dichotomy exists—irrespective of the technology employed—between studies that account for variation in the shape of bone cross-sections and those that do not. The different sets of density data currently available to zooarchaeologists vary tremendously in their accuracy. We review and evaluate the different techniques employed in the research of bone density patterns of mammalian fauna. Computed tomography produces the most accurate density data. For elements without medullary cavities, photon densitometry may provide density values of similar accuracy but only if a method of cross-sectional shape-adjustment is applied.     

The fractal geometry of ancient Maya settlement

Ancient Maya settlement patterns exhibit fractal geometry both within communities and across regions. Fractals are self-similar sets of fractional dimension. In this paper, we show how Maya settlement patterns are logically and statistically self-similar. We demonstrate how to measure the fractal dimensions (or Hausdorff–Besicovitch dimensions) of several data sets. We describe nonlinear dynamical processes, such as chaotic and self-organized critical systems, that generate fractal patterns. As an illustration, we show that the fractal dimensions calculated for some Maya settlement patterns are similar to those produced by warfare, supporting recent claims that warfare is a significant factor in Maya settlement patterning.     

Bias in Fish Bone Recovery from Differential Collection Techniques and Its Impact on Cultural Interpretation in California

ABSTRACT

While studies on recovery bias are numerous in the literature, the current research focuses on defining best practices in field collection techniques to provide a more accurate representative of site constituents, particularly fish remains. Methods to determine best practices included use of 1/4-inch, 1/8-inch, and 1/16-inch mesh to process excavated material from 10 × 10?cm and 40 × 40 cm-sized bulk column samples and from a 1 × 1 m test unit. Fish remains were compared to determine density and diversity differences between the samples and how these different data sets may impact cultural interpretations. This research shows that while collection of larger column samples processed using a smaller mesh size provides a more robust data set, the taxonomic richness present in a 1 × 1 m test unit provides complimentary data that are critical to understanding subsistence trends as a whole.     

Applying Measures of Spatial Autocorrelation: Computation and Simulation

Knowing about the challenges and opportunities of spatial autocorrelation is one thing, but applying the measures to one's own data is another matter entirely. While manual computation of the measures for toy data sets is possible, applying them to small data sets required the use of computers and thus software. This article will shed some light on how the measures were and are implemented in software and on implementation issues that are still not fully resolved.     

Peripheral Visions? A Cross-cultural Study of Rural Youths' Views on Migration

This study sets out to investigate anticipatory views concerning out-migration amongst rural youth. Utilising three age-group samples from rural Norway, Scotland and Sweden, young people were classified as prospective 'stayers', 'leavers' or 'returners'. Both qualitative and quantitative data show that 'stayers' see themselves as most contented with rurality. 'Leavers' are most negative to rural living. 'Returners', though also critical about rural living, are highly positive towards social relations in their communities. Furthermore, national and gender differences are evident. These varying adolescent constructions of rurality are discussed in relation to possible national policies.     

A CONDITIONALLY PARAMETRIC PROBIT MODEL OF MICRODATA LAND USE IN CHICAGO

Spatial data sets pose challenges for discrete choice models because the data are unlikely to be independently and identically distributed. A conditionally parametric spatial probit model is amenable to very large data sets while imposing far less structure on the data than conventional parametric models. We illustrate the approach using data on 474,170 individual lots in the City of Chicago. The results suggest that simple functional forms are not appropriate for explaining the spatial variation in residential land use across the entire city.     

Controlling the False Discovery Rate: A New Application to Account for Multiple and Dependent Tests in Local Statistics of Spatial Association

Assessing the significance of multiple and dependent comparisons is an important, and often ignored, issue that becomes more critical as the size of data sets increases. If not accounted for, false-positive differences are very likely to be identified. The need to address this issue has led to the development of a myriad of procedures to account for multiple testing. The simplest and most widely used technique is the Bonferroni method, which controls the probability that a true null hypothesis is incorrectly rejected. However, it is a very conservative procedure. As a result, the larger the data set the greater the chances that truly significant differences will be missed. In 1995, a new criterion, the false discovery rate (FDR), was proposed to control the proportion of false declarations of significance among those individual deviations from null hypotheses considered to be significant. It is more powerful than all previously proposed methods. Multiple and dependent comparisons are also fundamental in spatial analysis. As the number of locations increases, assessing the significance of local statistics of spatial association becomes a complex matter. In this article we use empirical and simulated data to evaluate the use of the FDR approach in appraising the occurrence of clusters detected by local indicators of spatial association. Results show a significant gain in identification of meaningful clusters when controlling the FDR, in comparison to more conservative approaches. When no control is adopted, false clusters are likely to be identified. If a conservative approach is used, clusters are only partially identified and true clusters are largely missed. In contrast, when the FDR approach is adopted, clusters are fully identified. Incorporating a correction for spatial dependence to conservative methods improves the results, but not enough to match those obtained by the FDR approach.     

Geostatistical Prediction and Simulation of Point Values from Areal Data

The spatial prediction and simulation of point values from areal data are addressed within the general geostatistical framework of change of support (the term support referring to the domain informed by each measurement or unknown value). It is shown that the geostatistical framework (i) can explicitly and consistently account for the support differences between the available areal data and the sought-after point predictions, (ii) yields coherent (mass-preserving or pycnophylactic) predictions, and (iii) provides a measure of reliability (standard error) associated with each prediction. In the case of stochastic simulation, alternative point-support simulated realizations of a spatial attribute reproduce (i) a point-support histogram (Gaussian in this work), (ii) a point-support semivariogram model (possibly including anisotropic nested structures), and (iii) when upscaled, the available areal data. Such point-support-simulated realizations can be used in a Monte Carlo framework to assess the uncertainty in spatially distributed model outputs operating at a fine spatial resolution because of uncertain input parameters inferred from coarser spatial resolution data. Alternatively, such simulated realizations can be used in a model-based hypothesis-testing context to approximate the sampling distribution of, say, the correlation coefficient between two spatial data sets, when one is available at a point support and the other at an areal support. A case study using synthetic data illustrates the application of the proposed methodology in a remote sensing context, whereby areal data are available on a regular pixel support. It is demonstrated that point-support (sub-pixel scale) predictions and simulated realizations can be readily obtained, and that such predictions and realizations are consistent with the available information at the coarser (pixel-level) spatial resolution.     

An Interdisciplinary Human-Environmental Examination of Effects Consistent with the Anthropocene in the Lower Illinois River Valley

Using archaeological and ecological data of animal communities, and fish communities in particular, we test for evidence consistent with the Anthropocene in the lower Illinois River valley across millennia. Environmental impacts by preindustrialized peoples may be minor compared to current alterations; however, this hypothesis is untested and should be assessed. Using the relative abundance of fish taxa, we tested for differences among archaeological and modern time periods, taking advantage of published zooarchaeological data sets and newly analyzed data. Collections from all archaeological time periods differed significantly from modern collections, but the relative abundance of fishes did not differ significantly among archaeological time periods. Sociopolitical context, material culture, plant-based subsistence patterns, and the use of animal classes shifted temporally, but these differences did not extend to the relative abundance of fish families. Our results suggest that dominating human influences on fish communities did not occur prior to the Late Woodland period in the lower Illinois River.     

Applying bootstrapped Correspondence Analysis to archaeological data

This paper examines the usefulness of bootstrapping in Correspondence Analysis when applied to archaeological data. By simulating and displaying possible variation within the data sets, bootstrapping provides us with a means to assess the stability of our CA maps and influences the interpretations we can place upon them. Five real data sets are examined and the results discussed. The paper concludes that bootstrapping is a useful and powerful way of examining the results of CA and should be employed on a regular basis.     

A REVIEW OF SUPERVISED AND UNSUPERVISED PATTERN RECOGNITION IN ARCHAEOMETRY*

Principal component, cluster and discriminant analysis are multivariate statistical methods that are widely used in archaeometry. They are examples of what are known in some literatures as unsupervised and supervised learning methods. Over the past 20 years or so, a wide variety of other learning methods have been developed that take advantage of modern computing power and, in some cases, have been designed to handle data sets more complex than those often used in archaeometric data analysis. To date, these methods have had little impact on archaeometry. This paper reviews, in a largely non‐technical manner, the ideas behind these newer methods; illustrates their use on a variety of data sets; and attempts to assess their potential for future archaeometric use.     

Lost in the Mail: the Inherent Errors of Mapping Australia Post Postcodes to ABS Derived Postal Areas

It is now common practice, by users of geographic information, to link data held at the postcode level to that obtained from the national census. This paper examines the relationship between Australia Post (AP) postcodes and Australian Bureau of Statistics (ABS) derived postal areas — which are an approximation of the former based on aggregated census collection districts (CDs). A group of adjacent ABS postal areas in northwest Melbourne was compared with the true AP postcode areas they purported to represent and the discrepancies were investigated. Firstly, shape mismatches were studied and their potential impacts upon resource allocation decisions were assessed. Next, comparisons of areas were undertaken. It was found that, in established inner city urban areas, the two sets of boundaries were highly correlated. However, outer suburban neighborhoods were identified as being particularly prone to major areal discrepancies. The implications of mismatches between these two key boundary data sources may be severe, given that management decisions and the allocation of public and private resources are often based on spatial statistical analyses which use these data sets. The authors acknowledge ABS efforts in providing information at the levels of aggregation that society demands. The introduction of ABS postal areas data has undoubtedly facilitated the use of demographic data in many sectors; it has, however, also caused some problems, for instance, when users assume that ABS postal areas are identical to AP postcodes. These issues could easily be avoided with the inclusion of more comprehensive metadata documentation accompanying ABS data. Research is continuing to develop a method by which agencies may derive common boundaries for their administrative units, yet still meet their own individual data and sampling requirements.     

Analysis of polychrome Iron Age glass vessels from Mediterranean I,II and III groups by LA-ICP-MS

In this work the analytical results obtained by ICP-MS with laser ablation solid sampling and SEM-EDS for some polychrome glass vessels from the Iron Age are presented and discussed. The samples, coming from Etruscan sites near Adria (Northern Italy), belong to the so-called Mediterranean Groups I, II and III and are dated from the 5th, 3rd and 2nd century B.C., respectively. To date, analytical data for only two sets of vessels of the Iron Age have been discussed in the literature. In spite of the low number of available samples, this is the first time that vessels of all three periods are analytically compared. Elemental concentration data show that the samples can be classified as low-magnesia-low potash (LMLK) soda-lime-silica glasses, with low phosphorus and titanium contents, in agreement with data for similar samples of the same age. Bivariate and multivariate analyses of the contents of many elements characterizing the siliceous sands showed three distinct sets corresponding to the three periods. Since the sets indicate different provenances of the sands it seems rational to assume that different glassmaking locations were involved. Chromophores and opacifiers of the blue bodies and the yellow, white and turquoise decorations of the vessels were analytically identified, while the nature of the corresponding ores was hypothesized.