Page 190 - 00. Complete Version - Progress Report IPEN 2014-2016

190 Nuclear Science and Technology | Progress Report

Fig 29 shows the in hyperspace. How-
Marajoara ceram- ever, canonical dis-
ic from Marajó Is- criminant analysis
land on the Ama- extracts a new set of
zon river delta area, variables that maxi-
highly elaborated by mize the differences
means of a process between two or more
of cultural change groups rather than
that occurred with- maximizing the total
in communities that variance of the data-
inhabited the area set. It is based on the
3500 years ago. Ra- assumption that the
diocarbon dates pooled variance–co-
place the period of variance matrix is an
major growth and accurate representa-
expansion of Marajo- tion of the total vari-
ara culture between ance and covariance.
the 5th and 14th cen- Fig 29. Funerary urn. It is assumed that all
turies. The Marajoara elements in the data
style seems to be related to different regions necessarily belong to one of the known groups.
within the Marajoara domain, as well as to Procrustes analysis with stopping rule is used
different chronological periods. The designs for selection of subsets of variables preserving
have a symbolic significance of a social or reli- multivariate data structure.
gious character with highly complex ceremo-
nial wares in form and decoration. Neutron Activation
Analysis and Electron
In order to test the archaeological hypothesis,
with the elements determined by INAA, spe- Spin Resonance for

cial attention is paid in establishing inter-sam- Fossil Samples Dating
ple similarity by means of advanced statistical
methods. The dataset obtained are studied us- The Electron Spin Resonance (ESR) dating is
ing several multivariate analyses, such as Ma- based on the fact that ionizing radiation can
halanobis distance, cluster analysis, principal create stable free radicals in insulating mate-
components analysis, kernel density, discrimi- rials, like tooth enamel and bones. The concen-
nant analysis, Procrustes analysis, self-organiz- tration of these radicals - determined by ESR -
ing maps, etc. Mahalanobis distance is used to is a function of the dose deposed in the sample
determine outliers in multivariate data. Clus- along the years. The accumulated dose of ra-
ter analysis using the squared-mean Euclide- diation, called Archeologial Dose (AD), is pro-
an distance represented in a dendrogram as duced by the exposition to environmental ra-
an initial step in the identification of groups. diation provided by U, Th, K and cosmic rays. If
In principal components analysis, the trans- the environmental dose rate (Dan) in the site
formation of the dataset is based on eigen- where the fossil sample is found is known, it
vector methods to determine the direction is possible to convert this dose into the age of
and the magnitude of maximum variance the sample by the equation: age=AD/Dan. The

Instituto de Pesquisas Energéticas e Nucleares