On an example of Nagarajan

K. R. Nagarajan constructed an example of a formal power series ring of dimension two, over a field of characteristic two, with the action of a cyclic group of order two, such that the ring of invariants is not noetherian. We point out how Nagarajan's example readily extends to each positive prime characteristic, and also to a characteristic zero example: There exists a formal power series ring of dimension two, over a field of characteristic zero, with an action of the infinite cyclic group, such that the ring of invariants is not noetherian. Both the positive characteristic and the characteristic zero examples are sharp in multiple ways

Relative efficiency in the branch network of a Greek bank : a quantitative analysis

Measuring and evaluating the efficient use of resources of Bank branches plays a decisive role in a Bank’s strategic planning. Usually, efficiency is measured by using accounting ratios, such as labor productivity, capital productivity, return on assets etc. When these ratios are properly used, they provide significant information regarding the effective operation of the branch, and contribute in carrying out intrabank comparisons and comparisons over a period of time. However, by using such ratios, an important part of the branch operation remains uncovered: the measurement of the effective use of the resources. New mathematical programming models that are related with the degree at which each branch makes use of its resources, are applied to deal with the weaknesses of such ratios. This study discuss the limitations of using accounting ratio analysis for assessing performance and, presents and interprets the results from the application of mathematical programming models in a sample of branches of a Greek Bank.peer-reviewe

On the renormalisation group for the boundary Truncated Conformal Space Approach

In this paper we continue the study of the truncated conformal space approach to perturbed boundary conformal field theories. This approach to perturbation theory suffers from a renormalisation of the coupling constant and a multiplicative renormalisation of the Hamiltonian. We show how these two effects can be predicted by both physical and mathematical arguments and prove that they are correct to leading order for all states in the TCSA system. We check these results using the TCSA applied to the tri-critical Ising model and the Yang-Lee model. We also study the TCSA of an irrelevant (non-renormalisable) perturbation and find that, while the convergence of the coupling constant and energy scales are problematic, the renormalised and rescaled spectrum remain a very good fit to the exact result, and we find a numerical relationship between the IR and UV couplings describing a particular flow. Finally we study the large coupling behaviour of TCSA and show that it accurately encompasses several different fixed points.Comment: 27 pages, 19 figure

Culture Changing: A Development and Empirical Exploration in the Greek Tax Administration

AbstractThe purpose of this study is to empirically explore for developing a cultural change intervention for an Empowered Organization Audit in Greek Tax Administration. By using modern theoretical and empirical approaches we examine the Empowering Organization Audit as directly affected by the prevailing management culture. This paper surveys issues related to Empowerment functions, by the following best practices to develop the full employee potential to their employees. Organizational Culture, Clear Vision, Wording the Values, Teamwork, Role of Management-Leadership, Transition the Power and Responsibility, Sharing information, Continuing Education and Training, Rewards Systems, Setting objectives. The findings of this study offer methods and procedures that can contribute a basis line for developing a culture change intervention for Empowering Organization Audit in the Greek Tax Administration and aims to changing employee's behavior

Investigating Molecule-Semiconductor Interfaces with Nonlinear Spectroscopies

Knowledge of electronic structures and transport mechanisms at molecule-semiconductor interfaces is motivated by their ubiquity in photoelectrochemical cells. In this dissertation, optical spectroscopies are used uncover the influence of electronic coupling, coherent vibrational motion, and molecular geometry, and other factors on dynamics initiated by light absorption at such interfaces. These are explored for a family of ruthenium bipyridyl chromophores bound to titanium dioxide. Transient absorption measurements show molecular singlet state electron injection in 100 fs or less. Resonance Raman intensity analysis suggests the electronic excitations possess very little charge transfer character. The connections drawn in this work between molecular structure and photophysical behavior contribute to the general understanding of photoelectrochemical cells. Knowledge of binding geometry in nanocrystalline films is challenged by heterogeneity of semiconductor surfaces. Polarized resonance Raman spectroscopy is used to characterize the ruthenium chromophore family on single crystal titanium dioxide . Chromophores display a broad distribution of molecular geometries at the interface, with increased variation in binding angle due to the presence of a methylene bridge, as well as additional phosphonate anchors. This result implies multiple binding configurations for chromophores which incorporate multiple phosphonate ligands, and indicates the need for careful consideration when developing surface-assembled chromophore-catalyst cells. Electron transfer transitions occurring on the 100 fs time scale challenge conventional second-order approximations made when modeling these reactions. A fourth-order perturbative model which includes the relationship between coincident electron transfer and nuclear relaxation processes is presented. Insights provided by the model are illustrated for a two-level donor molecule. The presented fourth-order rate formula constitutes a rigorous and intuitive framework for understanding sub-picosecond photoinduced electron transfer dynamics. Charge transfer systems fit by this model include catechol-sensitized titanium dioxide nanoparticles and a closely-related molecular complex. These systems exhibit vibrational coherence coincident with back-electron transfer in the first picosecond after excitation, which suggests that intramolecular nuclear motion strongly influences the electronic transfer process and plays an important role in the dynamics of interfacial systems following light absorption.Doctor of Philosoph

Using digital watermarking to enhance security in wireless medical image transmission

This is the published version of the article. Copyright 2010 Mary Ann Liebert Inc.During the last few years, wireless networks have been increasingly used both inside hospitals and in patients’ homes to transmit medical information. In general, wireless networks suffer from decreased security. However, digital watermarking can be used to secure medical information. In this study, we focused on combining wireless transmission and digital watermarking technologies to better secure the transmission of medical images within and outside the hospital. Methods: We utilized an integrated system comprising the wireless network and the digital watermarking module to conduct a series of tests. Results: The test results were evaluated by medical consultants. They concluded that the images suffered no visible quality degradation and maintained their diagnostic integrity. Discussion: The proposed integrated system presented reasonable stability, and its performance was comparable to that of a fixed network. This system can enhance security during the transmission of medical images through a wireless channel.The General Secretariat for Research and Technology of the Hellenic Ministry of Development and the British Council