Anisotropic Variance Functions in Geographically Weighted Regression Models

Most standard methods of statistical analysis used in the social and environmental sciences are built upon the basic assumptions of independence, homogeneity, and isotropy. A notable exception to this rule is the collection of methods used in geographical analysis, which have been designed to take into account serial dependence often observed in spatial data. In addition, recent developments, in particular the method of geographically weighted regression, have provided the tools to model non‐stationary processes, and thus evidence that challenges the assumption of homogeneity. The assumption of isotropy, however, although suspect, has received considerably less attention, and there is thus a need for tools to study anisotropy in a more systematic fashion. In this paper we expand the method of geographically weighted regression in a simple yet effective way to explore the topic of anisotropy in spatial processes. We discuss two different estimation situations and exemplify the proposed technical development by means of a case study. The results suggest that anisotropy issues might be a fairly common occurrence in spatial processes and/or in the statistical modeling of spatial processes.     

Holocene fire history of black colluvial soils revealed by pyrolysis-GC/MS: a case study from Campo Lameiro (NW Spain)

The colluvial soils of Galicia (NW Spain) are records of Holocene environmental change. In spite of the omnipresence of charcoal fragments in these soils, the effect of fires on the development of the Galician landscape and the potential role of past societies are poorly understood.     

THE ACEHÚCHE GOLD TORC: GOLD AND SACRED LAND ON THE SHORES OF THE TAGUS RIVER (CÁCERES,WESTERN SPAIN)

This article describes the important discovery of a Late Bronze Age gold torc that was unearthed in a field of Acehúche (Cáceres, Spain). It was buried underneath some rocks at a site near a river crossing over the Tagus river. In its immediate vicinity, archaeological remains dating from the Copper Age to the Late Bronze Age have been found, which indicates the long use of this crossing. Until recently here, there existed a ferry and a chapel; and the place went by the toponym of the Dehesa de San Cristóbal. Legend too has it that the water from the river had curative properties. All of these components have maintained the sacred nature of the spot, otherwise transformed over the course of time, and reflect an earlier sacred landscape with quite ancient roots.     

Assessing place-based identities in the early Middle Ages: a proposal for post-Roman Iberia

Sociological models of place-based identity can be used to better understand the social dynamics of local communities and how they interact with their surroundings. This paper explores how these theoretical models of belonging to a place, in tandem with communal cognitive maps, can be applied to post-Roman contexts, taking the Iberian Peninsula in the Visigothic period (sixth–eighth centuries) as a preliminary case study. We argue that this approach can give us not only a more complex understanding of community agencies but also allows us to reconsider the social context for past social interactions. Furthermore, it will open a new archaeological perspective for future work on the relations between groups and individuals with their built, social, and natural environments.     

Milling Cereals/Legumes and Stamping Bread in Mauretanian Tamuda (Morocco): An Interdisciplinary Study

African Archaeological Review - Recent archaeological excavations (2016–2019) in the city of Tamuda (northern Morocco) yielded evidence of commercial milling and bread-making facilities dated...     

Representative archaeological finds of <Emphasis Type="Italic">pietra ollare</Emphasis> from Comacchio (Italy): identifying provenance and high-T mineral breakdown reactions hindering lithotype classification

Three different lithotype groups have been recognized in representative fragments of pietra ollare artefacts found in the mediaeval archaeological excavations of Comacchio (Italy). Petrographic, mineralogical and chemical compositions clearly show that Valchiavenna and Valmalenco, in the Central Alps, represent the provenance areas of two of the pietra ollare groups, i.e. grey carbonate talc schist (also known as soapstone) and green chlorite schist, respectively. The third representative pietra ollare group consists of whitish-yellowish rocks inferred to be Alpine talc schists that have suffered some artificial pyrometamorphic transformation hindering their classification in the framework of pietra ollare lithotype categories and source localities reported in literature. A distinguishing feature of these high temperature-fired (HT-fired) talc schist samples is the occurrence of talc and chlorite dehydroxylation and subsolidus reaction products, mainly protoenstatite/enstatite + forsterite, together with relatively low loss on ignition values. These talc schists might have been exposed to temperatures >900 °C (with the resulting talc dehydroxylation producing a void-rich texture), but never reaching 1200 °C, which is the sintering temperature for soapstones. The whitish-yellowish artefacts were definitely not used as containers for cooking food at temperatures below or around 500–600 °C (as instead shown by the preservation of the original physical features of the grey pietra ollare lithotypes), but in some kind of higher-T pyrotechnological processes.     

Applying the technique of image classification to climate science: the case of Andalusia (Spain)

This paper proposes an empirical climate classification method based on the application of multivariate statistics. In this method, the technique of supervised and unsupervised image classification is used to classify the data and define climatic units. envi software is used to perform the image classification, specifically, the Iterative Self‐Organizing Data Analysis Technique algorithm. Supervised classification is also applied based on reference variables, fundamental parameters and a classifier. The obtained results display greater objectivity, reliability, operability, accessibility and reproducibility than previous climate classifications devised for the region of Andalusia (Spain), taking into account that these previous classifications were not based on quantitative criteria.