103 research outputs found
Development of new imaging techniques for the study and interpretation of late Rembrandt paintings
Recent macro-XRF scanning of Rembrandt’s Selfportrait from 1669 in the Mauritshuis – as part of the ReVisRembrandt project – has revealed significant new information about the pigments and build-up of the painting. The elemental distribution maps make clear that the umber-rich ground plays a very important role in the final appearance of this painting, information that is highly relevant for the study of this self-portrait, as well as many other late Rembrandt paintings. It was also possible to image the presence of organic lakes (by means of the potassium map) and bone black (by means of the calcium and phosphorus maps) in the upper paint layers. In addition to conventional investigative techniques, such as x-radiography and infrared imaging, it is anticipated macro-XRF scanning will become an important diagnostic tool for conservators and art historians alike
Splines and Wavelets on Geophysically Relevant Manifolds
Analysis on the unit sphere found many applications in
seismology, weather prediction, astrophysics, signal analysis, crystallography,
computer vision, computerized tomography, neuroscience, and statistics.
In the last two decades, the importance of these and other applications
triggered the development of various tools such as splines and wavelet bases
suitable for the unit spheres , and the
rotation group . Present paper is a summary of some of results of the
author and his collaborators on generalized (average) variational splines and
localized frames (wavelets) on compact Riemannian manifolds. The results are
illustrated by applications to Radon-type transforms on and
.Comment: The final publication is available at http://www.springerlink.co
Non-destructive characterisation and classification of ceramic artefacts using pEDXRF and statistical pattern recognition
Background: Portable energy dispersive X-ray fluorescence (pEDXRF) spectrometry analysis was applied for the characterisation of archaeological ceramic findings from three Neolithic sites in Serbia. Two dimension reduction techniques, principal component analysis (PCA) and scattering matrices-based dimension reduction were used to examine the possible classification of those findings, and to extract the most discriminant features. Results: A decision-making procedure is proposed, whose goal is to classify unknown ceramic findings based on their elemental compositions derived by pEDXRF spectrometry. As a major part of decision-making procedure, the possibilities of two dimension reduction methods were tested. Scattering matrices-based dimension reduction was found to be the more efficient method for the purpose. Linear classifiers designed based on the desired output allowed for 7 of 8 unknown samples from the test set to be correctly classified. Conclusions: Based on the results, the conclusion is that despite the constraints typical of the applied analytical technique, the elemental composition can be considered as viable information in provenience studies. With a fully-developed procedure, ceramic artefacts can be classified based on their elemental composition and well-known provenance
Sex Differences in Self-Concept and Symptoms of Depression During the Transition to College
In an investigation of sex differences in adaptation to college, real and ideal self-concept and symptoms of depression were studied longitudinally in a sample of 287 students. Survey data were collected at a summer orientation and one semester into freshman year. No sex differences in self-concept were found before college, but males' real self-concept became more positive over the transition. Females were more depressed than males at both times, although depressive symptom scores increased in both sexes. Real self-concept scores were negatively correlated with depressive symptoms in both sexes at both times, while the discrepancy between real and ideal self-concepts was positively correlated with depressive symptoms among females before college and in both sexes midway through freshman year. A one-year follow-up revealed that females' real self-concept scores increased to match those of males by mid-sophomore year. These sex differences are discussed in relation to psychological development during adolescence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45284/1/10964_2004_Article_411446.pd
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This thesis analyzes the structure of the Medvedev lattice of non-empty Π0 1 classes in 2 ω from the viewpoint of branching and non-branching degrees. This lattice is a countable distributive lattice with least and greatest element, which describes the relative information content of certain subsets of 2 ω. Chapter 1 is an introduction, providing background history, notation, and an overview of necessary concepts. Chapter 2 is essentially my paper “Non-Branching Degrees in the Medvedev Lat-tice of Π0 1 classes.”[1]. The chapter adds an additional theorem which strengthens the theorem on inseparable and not hyperinseparable classes. The chapter is also slightly more verbose. We begin by taking an existing condition, homogeneous, which implies non-branching and define two successively weaker conditions, hyperinseparable and inseparable. We then demonstrate that inseparable is equivalent to non-branching and is invariant under Medvedev equivalence. Finally, we prove separation theorems, namely the existence of an inseparable and not hyperinseparable degree and the existence of a hyperinseparable and not homogeneous degree. Chapter 3 defines a combinatorial method for constructing Π0 1 classes by priority arguments. This section does not contain any difficult proofs but abstracts many of the common elements of such constructions. The definitions and results are used i
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