Seriation by constrained correspondence analysis: a simulation study

One of the many areas in which Correspondence Analysis (CA) is an effectivemethod, concerns ordination problems. For example, CA is a well-knowntechnique for the seriation of archaeological assemblages. A problem withthe CA seriation solution, however, is that only a relative ordering of theassemblages is obtained. To improve the usual CA solution, a constrained CAapproach that incorporates additional information in the form of equalityand inequality constraints concerning the time points of the assemblages maybe considered. Using such constraints, explicit dates can be assigned to theseriation solution. In this paper, we extend the set of constraints that canbe used in CA by introducing interval constraints. That is, constraints thatput the CA\\ solution within a specific time-frame. Moreover, we study thequality of the constrained CA solution in a simulation study. In particular,by means of the simulation study we are able to assess how well ordinary andconstrained CA can recover the true time order. Furthermore, for theconstrained approach, we see how well the true dates are retrieved. Thesimulation study is set up in such a way that it mimics the data of a seriesof ceramic assemblages consisting of the locally produced tableware fromSagalassos (SW Turkey). We find that the dating of the assemblages on thebasis of constraints appears to work quite well.

Seriation by constrained correspondence analysis: a simulation study

One of the many areas in which Correspondence Analysis (CA) is an effective method, concerns ordination problems. For example, CA is a well-known technique for the seriation of archaeological assemblages. A problem with the CA seriation solution, however, is that only a relative ordering of the assemblages is obtained. To improve the usual CA solution, a constrained CA approach that incorporates additional information in the form of equality and inequality constraints concerning the time points of the assemblages may be considered. Using such constraints, explicit dates can be assigned to the seriation solution. In this paper, we extend the set of constraints that can be used in CA by introducing interval constraints. That is, constraints that put the CA\\ solution within a specific time-frame. Moreover, we study the quality of the constrained CA solution in a simulation study. In particular, by means of the simulation study we are able to assess how well ordinary and constrained CA can recover the true time order. Furthermore, for the constrained approach, we see how well the true dates are retrieved. The simulation study is set up in such a way that it mimics the data of a series of ceramic assemblages consisting of the locally produced tableware from Sagalassos (SW Turkey). We find that the dating of the assemblages on the basis of constraints appears to work quite well

Climate, people, fire and vegetation: new insights into vegetation dynamics in the Eastern Mediterranean since the 1st century AD

Anatolia forms a bridge between Europe, Africa and Asia and is influenced by all three continents in terms of climate, vegetation and human civilisation. Unfortunately, well-dated palynological records focussing on the period from the end of the classical Roman period until subrecent times are rare for Anatolia and completely absent for southwest Turkey, resulting in a lacuna in knowledge concerning the interactions of climatic change, human impact, and environmental change in this important region. Two well-dated palaeoecological records from the Western Taurus Mountains, Turkey, provide a first relatively detailed record of vegetation dynamics from late Roman times until the present in SW Turkey. Combining pollen, non-pollen palynomorphs, charcoal, sedimentological, archaeological data, and newly developed multivariate numerical analyses allows for the disentangling of climatic and anthropogenic influences on vegetation change. Results show changes in both the regional pollen signal as well as local soil sediment characteristics match shifts in regional climatic conditions. Both climatic as well as anthropogenic change had a strong influence on vegetation dynamics and land use. A moist environmental trend during the late-3rd century caused an increase in marshes and wetlands in the moister valley floors, limiting possibilities for intensive crop cultivation at such locations. A mid-7th century shift to pastoralism coincided with a climatic deterioration as well as the start of Arab incursions into the region, the former driving the way in which the vegetation developed afterwards. Resurgence in agriculture was observed in the study during the mid-10th century AD, coinciding with the Medieval Climate Anomaly. An abrupt mid-12th century decrease in agriculture is linked to socio-political change, rather than the onset of the Little Ice Age. Similarly, gradual deforestation occurring from the 16th century onwards has been linked to changes in land use during Ottoman times. The pollen data reveal that a fast rise in <i>Pinus</i> pollen after the end of the Beyşehir Occupation Phase need not always occur. The notion of high <i>Pinus</i> pollen percentages indicating an open landscape incapable of countering the influx of pine pollen is also deemed unrealistic. While multiple fires occurred in the region through time, extended fire periods, as had occurred during the Bronze Age and Beyşehir Occupation Phase, did not occur, and no signs of local fire activity were observed. Fires were never a major influence on vegetation dynamics. While no complete overview of post-BO Phase fire events can be presented, the available data indicates that fires in the vicinity of Gravgaz may have been linked to anthropogenic activity in the wider surroundings of the marsh. Fires in the vicinity of Bereket appeared to be linked to increased abundance of pine forests. There was no link with specifically wet or dry environmental conditions at either site. While this study reveals much new information concerning the impact of climate change and human occupation on the environment, more studies from SW Turkey are required in order to properly quantify the range of the observed phenomena and the magnitude of their impacts

Reconstructing Regional Trajectories: the Provenance and Distribution of Archaic to Hellenistic Ceramics in Central Pisidia (South-west Turkey)

Material Culture Studie

Intestinal parasites from the 2nd-5th century AD latrine in the Roman baths at Sagalassos (Turkey).

The aim of this research was to determine the species of intestinal parasite present in a Roman Imperial period population in Asia Minor, and to use this information to improve our understanding of health in the eastern Mediterranean region in Roman times. We analyzed five samples from the latrines of the Roman bath complex at Sagalassos, Turkey. Fecal biomarker analysis using 5β-stanols has indicated the feces were of human origin. The eggs of roundworm (Ascaris) were identified in all five samples using microscopy, and the cysts of the protozoan Giardia duodenalis (which causes dysentery) were identified multiple times in one sample using ELISA. The positive G. duodenalis result at Sagalassos is particularly important as it represents the earliest reliable evidence for this parasite in the Old World (i.e. outside the Americas). As both these species of parasite are spread through the contamination of food and water by fecal material, their presence implies that Roman sanitation technologies such as latrines and public baths did not break the cycle of reinfection in this population. We then discuss the evidence for roundworm in the writings of the Roman physician Galen, who came from Pergamon, a town in the same region as Sagalassos.This research was supported by the Belgian Programme on Interuniversity Poles of Attraction, the Research Fund of the University of Leuven and the Research Foundation Flanders

Thoughts on the archaeological residue of networks. A view from the East

The Unification of the Mediterranean World (400 BC - 400 AD

Late Achaemenid and Early Hellenistic Pisidian Material Culture from Düzen Tepe (SW Anatolia)

The continued importance of pottery studies for the development of the archaeological discipline can hardly be overstated. In this paper we discuss the pottery found at the settlement at Düzen Tepe (SW Anatolia), following the template of the well-established typological and fabric identification practices developed by the Sagalassos Archaeological Research Project for the Sagalassos Red Slip Ware production from Roman imperial times. A newly devised typology of the late Achaemenid to early Hellenistic (5th to 2nd centuries BCE) material of Düzen Tepe is presented. Comparisons with parallels in pottery material indicate that this material was firmly embedded in a (southwestern) Anatolian framework, generally matching a chronological window from the fourth to third centuries BCE

"Rhosica vasa": the quest continues

status: publishe