Page 43 - PR 2014 2016 07 Nuclear Science and Technology

Nuclear Science and Technology | Progress Report 185

provides the age. mation of the dataset
is based on eigenvec-
A typical vessel from tor methods to deter-
Amazon is presented mine the direction
in the Fig. 29. and the magnitude
of maximum vari-
Fig 29 shows the ance in hyperspace.
Marajoara ceramic However, canonical
from Marajó Island discriminant anal-
on the Amazon riv- ysis extracts a new
er delta area, high- set of variables that
ly elaborated by maximize the differ-
means of a process ences between two
of cultural change or more groups rather
that occurred with- than maximizing the
in communities total variance of the
that inhabited the dataset. It is based on
area 3500 years ago. Fig 29. Funerary urn. the assumption that
Radiocarbon dates the pooled variance–
place the period of major growth and expan- covariance matrix is an accurate represen-
sion of Marajoara culture between the 5th and tation of the total variance and covariance.
14th centuries. The Marajoara style seems to be It is assumed that all elements in the data
related to different regions within the Mara- necessarily belong to one of the known groups.
joara domain, as well as to different chrono- Procrustes analysis with stopping rule is used
logical periods. The designs have a symbolic for selection of subsets of variables preserving
significance of a social or religious character multivariate data structure.
with highly complex ceremonial wares in form
and decoration. Neutron Activation
Analysis and Electron
In order to test the archaeological hypothesis,
with the elements determined by INAA, special Spin Resonance for

attention is paid in establishing inter-sample Fossil Samples Dating
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 con-
nant analysis, Procrustes analysis, self-organiz- centration of these radicals - determined by
ing maps, etc. Mahalanobis distance is used to ESR - is a function of the dose deposed in the
determine outliers in multivariate data. Cluster sample along the years. The accumulated dose
analysis using the squared-mean Euclidean of radiation, called Archeologial Dose (AD), is
distance represented in a dendrogram as an produced by the exposition to environmental
initial step in the identification of groups. In radiation provided by U, Th, K and cosmic rays.
principal components analysis, the transfor- If the environmental dose rate (Dan) in the site