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Search Results: 1 - 10 of 1475 matches for " Konstantinos Kazakos "
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Unusual Intramuscular Lipoma of Deltoid Muscle
Stylianos Kapetanakis , Jiannis Papathanasiou , Antonios Dermon , Alexandra Dimitrakopoulou , Athanasios Ververidis , Pelagia Chloropoulou , Konstantinos Kazakos
Folia Medica , 2010, DOI: 10.2478/v10153-010-0050-x
Abstract: Lipomas are common soft tissue tumors usually located under the skin. Nevertheless, intramuscular lipomas of deltoid muscle are unusual tumors. We present a case of 74 years old woman with an intramuscular like clepsydra lipoma of deltoid muscle. The lesion was a palpable soft mass at the lateral side of the humerus. The patient had no previous history of trauma. The main symptom was pain only in abduction and extension. Imaging, pathological findings and surgical excision are discussed.
Determinants of vascular function in patients with type 2 diabetes
Katerina K Naka, Katerina Papathanassiou, Aris Bechlioulis, Nikolaos Kazakos, Konstantinos Pappas, Stelios Tigas, Dimitrios Makriyiannis, Agathocles Tsatsoulis, Lampros K Michalis
Cardiovascular Diabetology , 2012, DOI: 10.1186/1475-2840-11-127
Abstract: We studied 165 T2DM patients without known macrovascular or microvascular disease. Standard demographic (age, gender, cardiovascular risk factors, medications), clinical (body mass index, blood pressure) and laboratory (glucose, glycated hemoglobin, lipids, renal function) parameters were included in analyses. Brachial artery flow-mediated dilation (FMD), nitrate mediated dilation (NMD) and Carotid-Femoral Pulse Wave Velocity (PWV) were measured.Median age was 66 years and duration since T2DM diagnosis was 10 years, 70% were females and 79% hypertensives, while only 10% had a glycated hemoglobin <7%. FMD was positively associated with NMD (r 0.391, P?<?0.001), while PWV was inversely associated with FMD (r -0.218, P?=?0.014) and NMD (r -0.309, P?<?0.001). Time since diagnosis of diabetes was the single independent predictor of FMD (β -0.40, P?=?0.003). Increased age and fasting glucose and the presence of hypertension were independent predictors of decreased NMD (P?<?0.001). Increased age and systolic blood pressure were independently associated with increased PWV (P?<?0.001).In T2DM patients, impairment of endothelium-dependent vasodilation was independently associated only with longer diabetes duration while no association with other established risk factors was found. Vascular smooth muscle dysfunction and increased arterial stiffness were more prominent in older T2DM patients with hypertension. Worse glycemic control was associated with impaired vascular smooth muscle function.Type 2 diabetes mellitus (T2DM) is independently associated with an increased risk for cardiovascular diseases (CVD) [1] that is primarily due to the early development of advanced atherosclerotic vascular changes [2]. Vascular endothelial and smooth muscle cell dysfunction as well as large arterial stiffness are considered to be markers of subclinical atherosclerosis with a significant prognostic role in high risk populations [3-10]. Endothelial dysfunction, as assessed by decreased endoth
Sequential Tests for the Detection of Voice Activity and the Recognition of Cyber Exploits  [PDF]
Ehab Etellisi, P. Papantoni-Kazakos
Communications and Network (CN) , 2011, DOI: 10.4236/cn.2011.34022
Abstract: We consider the problem of automated voice activity detection (VAD), in the presence of noise. To attain this objective, we introduce a Sequential Detection of Change Test (SDCT), designed at the independent mixture of Laplacian and Gaussian distributions. We analyse and numerically evaluate the proposed test for various noisy environments. In addition, we address the problem of effectively recognizing the possible presence of cyber exploits in the voice transmission channel. We then introduce another sequential test, designed to detect rapidly and accurately the presence of such exploits, named Cyber Attacks Sequential Detection of Change Test (CA-SDCT). We analyse and numerically evaluate the latter test. Experimental results and comparisons with other proposed methods are also presented.
Stochastic Binary Neural Networks for Qualitatively Robust Predictive Model Mapping  [PDF]
A. T. Burrell, P. Papantoni-Kazakos
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.529070
Abstract: We consider qualitatively robust predictive mappings of stochastic environmental models, where protection against outlier data is incorporated. We utilize digital representations of the models and deploy stochastic binary neural networks that are pre-trained to produce such mappings. The pre-training is implemented by a back propagating supervised learning algorithm which converges almost surely to the probabilities induced by the environment, under general ergodicity conditions.
Random Access Algorithms in Packet Networks—A Review of Three Research Decades  [PDF]
A. T. Burrell, P. Papantoni-Kazakos
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.510072
Abstract: We present a coherent and systematic review of Random Access Algorithms for packet networks, as developed over three and a half decades. We consider the appropriate user models and we classify the algorithms according to the channel sensing constraints imposed. We also present a review of the analytical methodologies required for the performance analysis of these algorithms.
Parametrically Optimal, Robust and Tree-Search Detection of Sparse Signals  [PDF]
A. T. Burrell, P. Papantoni-Kazakos
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.43042
Abstract:

We consider sparse signals embedded in additive white noise. We study parametrically optimal as well as tree-search sub-optimal signal detection policies. As a special case, we consider a constant signal and Gaussian noise, with and without data outliers present. In the presence of outliers, we study outlier resistant robust detection techniques. We compare the studied policies in terms of error performance, complexity and resistance to outliers.

Lack of effects of pioglitazone on cardiac function in patients with type 2 diabetes and evidence of left ventricular diastolic dysfunction: a tissue doppler imaging study
Katerina K Naka, Konstantinos Pappas, Katerina Papathanassiou, Nikolaos D Papamichael, Nikolaos Kazakos, Chryssanthi Kanioglou, Demetrios Makriyiannis, Christos S Katsouras, Kostas Liveris, Agathocles Tsatsoulis, Lampros K Michalis
Cardiovascular Diabetology , 2010, DOI: 10.1186/1475-2840-9-57
Abstract: Eighty-eight asymptomatic DM2 patients on metformin and/or sulfonylureas, aged 64.5 ± 7.7 years, without known cardiovascular disease, with normal LV systolic function and evidence of LVDD were randomly assigned to pioglitazone 30 mg/day (n = 42) or an increase in dose of other oral agents (n = 39) for 6 months. All patients underwent transthoracic conventional and Tissue Doppler Imaging echocardiography at baseline and follow-up. The primary end-point was change in early diastolic velocity of the mitral annulus (E').Improvement of glycaemic control was similar in the 2 groups. A significant difference (p < 0.05) between the 2 groups was found in the treatment-induced changes in fasting insulin, the insulin resistance index HOMA, HDL cholesterol, triglycerides, diastolic blood pressure (all in favor of pioglitazone) and in body weight (increase with pioglitazone). No significant changes were observed in any echocardiographic parameter in either group and did not differ between groups (p = NS for all). E' increased non-significantly and to a similar extent in both groups (p = NS).In asymptomatic DM2 patients with LVDD, the addition of pioglitazone to oral conventional treatment for 6 months does not induce any adverse or favorable changes in LV diastolic or systolic function despite improvements in glycaemic control, insulin sensitivity, lipid profile, and blood pressure.Diabetes mellitus (DM) is associated with a substantially increased risk of developing heart failure (HF) [1]. Although the association between diabetes and HF has been well established, the underlying mechanisms remain vague. Co-existing morbidities, such as hypertension, microangiopathy, myocardial ischemia and renal dysfunction may explain the development of HF in type 2 DM (DM2) patients. The existence of 'diabetic cardiomyopathy', a distinct clinical process leading to HF in diabetic patients regardless of the presence of atherosclerosis and hypertension has also been suggested [2,3]. Left ventr
Beyond the Dirac Phase Factor: Dynamical Quantum Phase-Nonlocalities in the Schrödinger Picture  [PDF]
Konstantinos Moulopoulos
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.211156
Abstract: Generalized solutions of the standard gauge transformation equations are presented and discussed in physical terms. They go beyond the usual Dirac phase factors and they exhibit nonlocal quantal behavior, with the well-known Relativistic Causality of classical fields affecting directly the phases of wavefunctions in the Schrödinger Picture. These nonlocal phase behaviors, apparently overlooked in path-integral approaches, give a natural account of the dynamical nonlocality character of the various (even static) Aharonov-Bohm phenomena, while at the same time they seem to respect Causality. For particles passing through nonvanishing magnetic or electric fields they lead to cancellations of Aharonov-Bohm phases at the observation point, generalizing earlier semiclassical experimental observations (of Werner & Brill) to delocalized (spread-out) quantum states. This leads to a correction of previously unnoticed sign-errors in the literature, and to a natural explanation of the deeper reason why certain time-dependent semiclassical arguments are consistent with static results in purely quantal Aharonov-Bohm configurations. These nonlocalities also provide a remedy for misleading results propagating in the literature (concerning an uncritical use of Dirac phase factors, that persists since the time of Feynman’s work on path integrals). They are shown to conspire in such a way as to exactly cancel the instantaneous Aharonov-Bohm phase and recover Relativistic Causality in earlier “paradoxes” (such as the van Kampen thought-experiment), and to also complete Peshkin’s discussion of the electric Aharonov-Bohm effect in a causal manner. The present formulation offers a direct way to address time-dependent single- vs double-slit experiments and the associated causal issues—issues that have recently attracted attention, with respect to the inability of current theories to address them.
The Physics of an Absolute Reference System  [PDF]
Konstantinos Patrinos
Journal of Applied Mathematics and Physics (JAMP) , 2019, DOI: 10.4236/jamp.2019.73033
Abstract: The hypothesis of the absolute reference system, unlike the existing physics theories, is not based on the concept of relativity (that is, it is not based on a relativistic description like Galileo’s relativity or Einstein’s theory of relativity). The absolute reference system is the framework of material in which any activity in the universe has begun. Also, each inertial reference system is accompanied by a peculiar electromagnetic wave due to the structure of matter. The physics of the absolute system of reference is based on three basic principles. The first of these principles is that the electromagnetic field quantitative estimates are made in the inertial reference system of the source of the electromagnetic field. The second principle is that the basic constituent of matter is “bound photons, which make up the internal structure of the elementary particles. The third principle is that the framework of material of an inertial system undergoes a contraction of length which is a real physical contraction and a corresponding real change in “time flow, not due to the geometry of space-time, but is due to the internal operation of the micro-structure of matter. These principles have the effect of changing the relativistic physical magnitudes, such as velocity, momentum and kinetic energy, into physical magnitudes described as absolute. This theory is consistent with experimental data so far and provides satisfactory answers to physics problems such as dark matter, particle physics experiments to confirm the dynamics, interpretation of experimental results of measurement of neutrinos velocity that are incompatible with the relativity, and magnetic induction experiments which are not explained by the classical electromagnetic theory.
Quality of Service in Mobile Ad Hoc Networks
Li Wei,Guizani Mohsen,Kazakos Demetrios
EURASIP Journal on Wireless Communications and Networking , 2006,
Abstract:
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