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Search Results: 1 - 10 of 10844 matches for " Andreas Georgiou "
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A Global Solution of the Einstein-Maxwell Field Equations for Rotating Charged Matter  [PDF]
Andreas Georgiou
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.329168
Abstract: A stationary axially symmetric exterior electrovacuum solution of the Einstein-Maxwell field equations was obtained. An interior solution for rotating charged dust with vanishing Lorentz force was also obtained. The two spacetimes are separated by a boundary which is a surface layer with surface stress-energy tensor and surface electric 4-current. The layer is the spherical surface bounding the charged matter. It was further shown, that all the exterior physical quantities vanished at the asymptotic spatial infinity where spacetime was shown to be flat. There are two different sets of junction conditions: the electromagnetic junction conditions, which were expressed in the traditional 3-dimensional form of classical electromagnetic theory; and the considerably more complicated gravitational junction conditions. It was shown that both—the electromagnetic and gravitational junction conditions—were satisfied. The mass, charge and angular momentum were determined from the metric. Exact analytical formulae for the dipole moment and gyromagnetic ratio were also derived. The conditions, under which the latter formulae gave Blackett’s empirical result for rotating stars, were investigated.
The Angular Momenta, Dipole Moments and Gyromagnetic Ratios of the Neutron and the Muon  [PDF]
Andreas Georgiou
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.67104
Abstract: The dipole moments, angular momenta and gyromagnetic ratios of the electron and the proton were obtained earlier. In this note, we derive the corresponding expressions for the neutron and the muon. This work relies on the results obtained earlier for the angular momenta and dipole moments of rotating spherical bodies.
Risk-based decision making and risk management of European Union regional programs
Michalopoulos Evangelos,Georgiou Andreas C.,Paparrizos Konstantinos
Yugoslav Journal of Operations Research , 2008, DOI: 10.2298/yjor0801075m
Abstract: This paper presents a generalized method for management decision making incorporating risk assessment techniques. The risk based decision making methodology is applied to European Union expenditure programs used to implement its regional policy, such as the community support framework, community initiatives, special initiatives and other European policies. An example is presented for the development of an audit (inspection) program in the region of West Macedonia, Greece, during the implementation of the 3rd Community Structural Support Framework Operational Program. The generic nature of the method permits its use in the management of similar European regional programs in Greece and other European countries. It is also applicable to many other industries interested in applying risk-based management decisions to physical or process based systems. .
The Angular Momenta Dipole Moments and Gyromagnetic Ratios of the Electron and the Proton  [PDF]
A. Georgiou
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.514125
Abstract:

We had previously obtained analytical formulae for the dipole moments and angular momenta of rotating spherical bodies. The resulting formulae were applied to the Sun, the star 78 Virginis and the Earth. The agreement of the theoretical formulae with the actual real situations is indeed remarkable. In this note we apply the same formulae to the electron and the proton, using the classical values of the radii, so no quantum mechanical treatment is considered.

The Development of the Greek Personality Assessment Inventory  [PDF]
Dimitrios Georgiou Lyrakos
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.28122
Abstract: Presented in the current report are the reliability analysis of the Greek Personality Assessment Inventory (PAI), the differences between the means and the standard deviation (SD) of the Greek and the US sample and the creation of the maximum non-clinical T Scores for each of the scale and subscale produced by the Greek standardization sample. The PAI is considered, in the US and in many European countries, one of the most reliable multidimensional psychometric inventories. The PAI consists of 344 questions that are separated in non-over- lapping scales of clinical, treatment focus, personality and validity context. The present, mixed design study had 1870 participants, males and females between the ages of 20 and 55.The participants were 1120 non-clinical (standardization sample), 450 psychiatric inpatients and 300 psychiatric outpatients, who were gathered from 4 major regions of Greece.
Severe Thyrotoxicosis Does Not Accelerate 1a-Hydroxylation of 25-Hydroxyvitamin D3 in Dogs. Experimental Study  [PDF]
Christos Georgiou Velentzas
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.412093
Abstract:

Two healthy dogs weighing 18 kg and 13 kg each received an intravenous injection of 7 μg/kg 25-hydroxyvitamin D3 (25OHD3). Subsequently, they were blood-sampled in order to determine the plasma levels of 25(OH)D3 over 4-hourly time intervals and for a time period of 24 hours. After a period of 18 days since the last blood sampling, the animals were brought to a hyperthyroid state and the intravenous injection of 7 μg/kg 25OHD3 was repeated. Blood sampling was performed every 4 hours and over a time period of 24 hours in order to determine the levels of 25OHD3. The graphic plotting of plasma levels of 25OHD3 in the euthyroid state did not differ from that in the hyperthyroid state. This finding in dog animal experimentation is indicative that the increased levels of thyroid hormones did not affect the activity of CYP27B1 and CYP24A1 enzymes that are related to the catabolism of 25OHD3 over a minimum of 24 hours period.

Vitamin D receptor gene polymorphisms in multiple sclerosis patients in northwest Greece
Chrissa Sioka, Stylianos Papakonstantinou, Sofia Markoula, Foteini Gkartziou, Athanasia Georgiou, Ioannis Georgiou, Sygliti-Henrietta Pelidou, Athanassios P Kyritsis, Andreas Fotopoulos
Journal of Negative Results in BioMedicine , 2011, DOI: 10.1186/1477-5751-10-3
Abstract: The mean age of patients was 39 ± 10.5 years compared to 38.7 ± 10.7 years of the controls (p = 0.86), the BMI was 24.8 ± 4.2 kg/m2 compared to 25.7 ± 4.8 kg/m2 of the controls (p = 0.23), the BMD in the lumbar spine 0.981 ± 0.15 compared to 1.025 ± 013 of the controls (p = 0.06) and the total hip BMD was 0.875 ± 0.14 compared to 0.969 ± 0.12 of the controls (p < 0.001). There were no differences of the Taq-I (TT, CT, CC) and Bsm-I genotypes (GG, GA, AA) and allelic frequencies between MS and control individuals. Multivariate analysis also failed to show any association of the Taq-I and Bsm-I polymorphisms and MS or sex, BMI, BMD and smoking history.This study suggests that the Taq-I and Bsm-I polymorphisms of the VDR gene are not associated with MS risk, BMI or BMD in the Greek population studied.Multiple sclerosis (MS) is a progressive demyelinating disease of the central nervous system (CNS) that occurs mainly in young adults, frequently leading to substantial disability several years after diagnosis [1]. Vitamin D is essential for bone and mineral homeostasis and exhibits immunoregulatory and anti-inflammatory properties [2]. Abnormal regulation of vitamin D metabolism has been linked to MS and other diseases such as type 1 diabetes, cancer, and osteoporosis [3-7]. Vitamin D acts through the vitamin D receptor (VDR) and the membrane associated rapid response steroid binding receptor (MARRS) [8]. Certain polymorphisms of the VDR gene may modify vitamin D function and metabolism and have been examined in studies evaluating the role of vitamin D on MS [9].Several such studies that have investigated the role of VDR gene polymorphisms in various ethnic groups have produced conflicting results. A Japanese study reported an association between the Bsm-I VDR gene allelic polymorphism and MS [10]. An Australian MS case-control study found a significant difference of the Taq-I polymorphism genotype distribution in MS patients [11]. Similar results were reported in other s
A new higher-spin theory of supergravity in 2+1 dimensions
George Georgiou
Physics , 2015,
Abstract: We construct a novel higher-spin theory of gravity in 2+1 spacetime dimensions. The construction is based on a higher-spin super-algebra extending the Poincare group. Our algebra accommodates all integer and half-integer spins from 1 to infinity and, in contrast to the results in the existing literature, allows for an infinite number of particles of spin s. Subsequently, we generalise the construction to include a cosmological constant. In this case, the higher-spin group is an extension of the AdS or dS group and contains only bosonic generators. Treating the higher-spin groups as gauge groups we write down the Chern-Simons like action, the transformation laws for the fields of the theory and their equations of motion in each of the three aforementioned cases. Finally, we comment on the generalisation of our algebras in $d+1$ dimensions.
Positive and zero temperature polymer models
Nicos Georgiou
Mathematics , 2012,
Abstract: We present results about large deviations and laws of large numbers for various polymer related quantities. In a completely general setting and strictly positive temperature, we present results about large deviations for directed polymers in random environment. We prove quenched large deviations (and compute the rate functions explicitly) for the exit point of the polymer chain and the polymer chain itself. We also prove existence of the upper tail large deviation rate function for the logarithm of the partition function. In the case where the environment weights have certain log-gamma distributions the computations are tractable and allow us to compute the rate function explicitly. At zero temperature, the polymer model is now called a last passage model. With a particular choice of random weights, the last passage model has an equivalent representation as a particle system called Totally Asymmetric Simple Exclusion Process (TASEP). We prove a hydrodynamic limit for the macroscopic particle density and current for TASEP with spatially inhomogeneous jump rates given by a speed function that may admit discontinuities. The limiting density profiles are described with a variational formula. This formula enables us to compute explicit density profiles even though we have no information about the invariant distributions of the process. In the case of a two-phase flux for which a suitable p.d.e. theory has been developed we also observe that the limit profiles are entropy solutions of the corresponding scalar conservation law with a discontinuous speed function.
On maximal surfaces in the space of oriented geodesics of hyperbolic 3-space
Nikos Georgiou
Mathematics , 2010,
Abstract: We study area-stationary, or maximal, surfaces in the space ${\mathbb L}({\mathbb H}^3)$ of oriented geodesics of hyperbolic 3-space, endowed with the canonical neutral K\"ahler structure. We prove that every holomorphic curve in ${\mathbb L}({\mathbb H}^3)$ is a maximal surface. We then classify Lagrangian maximal surfaces $\Sigma$ in ${\mathbb L}({\mathbb H}^3)$ and prove that the family of parallel surfaces in ${\mathbb H}^3$ orthogonal to the geodesics $\gamma\in\Sigma$ form a family of equidistant tubes around a geodesic.
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