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Search Results: 1 - 10 of 41 matches for " Chrysoula Pipili "
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Unusual hand radiographic presentation in a patient on hemodialysis
Chrysoula Pipili,Eirini Grapsa,Helen Tzanatos
Mediterranean Journal of Hematology and Infectious Diseases , 2012, DOI: 10.4084/mjhid.2012.
Abstract: We read with great interest the report of Alcelik et al. 1 (May 16 issue), about the case of upper extremity thrombosis caused by hand knitting. Knitting is also a popular Greek leisure activity, which gratify women of all ages, even when they suffer from serious health problems. Repetitive minor injuries caused from knitting may result in ......
On a Gauss-Kuzmin-Type Problem For a Generalized Gauss-Kuzmin Operator
Chrysoula Ganatsiou
International Journal of Mathematics and Mathematical Sciences , 2011, DOI: 10.1155/2011/514746
Abstract: A generalized limit probability measure associated with a random system with complete connections for a generalized Gauss-Kuzmin operator, only for a special case, is defined, and its behaviour is investigated. As a consequence a specific version of Gauss-Kuzmin-type problem for the above generalized operator is obtained. 1. Introduction Let be the Banach space of complex-valued continuous functions on under the supremum norm, and let , . Then for every and for every the function introduced by Fluch [1] and defined by for all , is called a generalized Gauss-Kuzmin operator. The present paper arises as an attempt to determine a generalized limit probability measure, only for a special case, associated with a random system with complete connections for the above generalized Gauss-Kuzmin operator obtained in Ganatsiou [2], for every . This will give us the possibility to obtain a specific variant of Gauss-Kuzmin-type problem for the above operator. Our approach is given in the context of the theory of dependence with complete connections (see Iosifescu and Grigorescu [3]). For a more detailed study of the theory and applications of dependence with complete connections to the metrical problems and other interesting aspects of number theory we refer the reader to [4–9] and others. The paper is organized as follows. In Section 2, we present all the necessary results regarding the ergodic behaviour of a random system with complete connections associated with the generalized Gauss-Kuzmin operator obtained in [2], in order to make more comprehensible the presentation of the paper. In Section 3, we introduce the determination of a limit probability measure associated with the above random system with complete connections, only for a special case, for every , which will give us the possibility to study in Section 4 a specific version of the associated Gauss-Kuzmin type problem. 2. Auxiliary Results For every , we consider the function defined by and set where , for every and for every . Then we obtain the following statement which gives a relation deriving from an analogous of the Gauss- Kuzmin type equation. Proposition 2.1. The function satisfies for any and . Furthermore we obtain the following. Proposition 2.2. For every , the function defines a transition probability function from to , where and the power set of . Equation (2.3) and Proposition 2.2 lead to the consideration of a family of random systems with complete connections (RSCCs) where In the next, we consider the transition probability function , , of the Markov chain associated with the family of the
On the Study of Transience and Recurrence of the Markov Chain Defined by Directed Weighted Circuits Associated with a Random Walk in Fixed Environment
Chrysoula Ganatsiou
Journal of Probability and Statistics , 2013, DOI: 10.1155/2013/424601
Abstract: By using the cycle representation theory of Markov processes, we investigate proper criterions regarding transience and recurrence of the corresponding Markov chain represented uniquely by directed cycles (especially by directed circuits) and weights of a random walk with jumps in a fixed environment. 1. Introduction A systematic research has been developed (Kalpazidou [1], MacQueen [2], Minping and Min [3], Zemanian [4], and others) in order to investigate representations of the finite-dimensional distributions of Markov processes (with discrete or continuous parameter) having an invariant measure, as decompositions in terms of the cycle (or circuit) passage functions: for any directed sequence (or ) of states called a cycle (or a circuit), , of the corresponding Markov process. The representations are called cycle (or circuit) representations while the corresponding discrete parameter Markov processes generated by directed circuits , , are called circuit chains. Following the context of the theory of Markov processes’ cycle-circuit representation, the present work arises as an attempt to investigate proper criterions regarding the properties of transience and recurrence of the corresponding Markov chain represented uniquely by directed cycles (especially by directed circuits) and weights of a random walk with jumps (having one elastic left barrier) in a fixed ergodic environment (Kalpazidou [1], Derriennic [5]). The paper is organized as follows. In Section 2, we give a brief account of certain concepts of cycle representation theory of Markov processes that we will need throughout the paper. In Section 3, we present some auxiliary results in order to make the presentation of the paper more comprehensible. In particular, in Section 3, a random walk with jumps (having one elastic left barrier) in a fixed ergodic environment is considered, and the unique representations by directed cycles (especially by directed circuits) and weights of the corresponding Markov chain are investigated. These representations will give us the possibility to study proper criterions regarding transience and recurrence of the abovementioned Markov chain, as it is described in Section 4. Throughout the paper, we will need the following notations: 2. Preliminaries Let us consider a denumerable set S. Then the directed sequence modulo the cyclic permutations, where , , completely defines a directed circuit in . The ordered sequence associated with the given directed is called a directed cycle in . A directed circuit may be considered as , if there exists an , such that , , ,
Yule-Walker Estimation for the Moving-Average Model
Chrysoula Dimitriou-Fakalou
International Journal of Stochastic Analysis , 2011, DOI: 10.1155/2011/151823
Abstract: The standard Yule-Walker equations, as they are known for an autoregression, are generalized to involve the moments of a moving-average process indexed on any number of dimensions. Once observations become available, new moments estimators are set to imitate the theoretical equations. These estimators are not only consistent but also asymptotically normal for any number of indexes. Their variance matrix resembles a standard result from maximum Gaussian likelihood estimation. A simulation study is added to conclude on their efficiency. 1. Introduction At first, processes taking place on more than one dimension were considered on surfaces or in the three-dimensional space for the sake of spatial dynamics. Next, the time series Autoregressive Moving-Average model could be as well used to clothe the covariance dependence of spatial point processes. Nevertheless, the assumptions of causality and invertibility were based on conventional orderings of the vector indexes, as these were introduced by Whittle [1] and generalized by Guyon [2], and they failed to look natural on the spatial axes. The more general bilateral equations considered by Whittle [1] also related to serious problems during the estimation of the parameters. Besag’s [3] automodels as well as Besag’s [4] equations for observations on irregular sites moved in a new direction but the weaknesses during the estimation remained. The inclusion of the time axis has provided more convenience for the spatial analysis that may be summarized in two ways. On the one hand when the observations are collected on irregular sites, the asymptotic properties of the estimators for the spatial dependence parameters can now be established as the number of timings only increases to infinity; for example, Dimitriou-Fakalou [5] has proposed a methodology on how to proceed. On the other hand when the regular recordings are increasing towards all the spatial as well as the time axes, the unilateral ordering of indexes can now be arranged in a meaningful way and the causal and invertible ARMA model may be preferred as a natural spatiotemporal equation. Special cases of the ARMA model are the pure autoregressive and moving-average equations and they both relate to useful properties as in the spectral density of interest. The autoregressive process uses a spectral density with “finite denominator”, which for Gaussian processes [3] translates into a finite conditional expectation of any value based on all other values. A moving-average process uses a “finite numerator” in the spectral density, resulting in the autocovariance
A theoretical approach of Asperger’s syndrome in children
Chrysoula Valamoutopoulou,Ioannis Koutelekos
To Vima tou Asklipiou , 2010,
Abstract: The Asperger’s Syndrome is reported in the pervasive developmental disorders and was categorized as a separate disorder, initially in the ICD‐10 (World Health Organization, 1992) and afterwards in the DSM‐IV (American Psychiatric Organization, 1994). The Asperger’s Syndrome is distinguished by a team of symptoms that concern the low output in the social interaction and the communication dexterities, as well as the increased stereotypical behavior in various activities and interests.Aim: The aim of this present study was the descriptive review of bibliography concerning the epidemiology, the differential diagnosis from the autism, the etiology, the diagnosis, the therapeutic approaches and the adaptation difficulty of the family environment, with regard to the investigation of the Asperger ’s syndrome.Material and method: In the present review, the methodology that was followed included specialized electronic research with regard to the Asperger’s syndrome in children, using special keywords.Results: The review of the bibliography showed that the individuals with Asperger’s syndrome experience really big difficulties in elementary social behaviors, as failure in the growth and creation of friendly relations or in the search of amusing activities with others. Also, they face difficulties in the comprehension of not verbal communication (body language) and the other’s expressions, the attitudes of body and the eye contact.Conclusions: The precocious recognition of Asperger’ s syndrome is imperative, with final objective the continuous briefing and sensitization of all health professionals as well as the wider public toward this, under the prism of interdisciplinary approach.
Asperger Syndrome in children
Chrysoula Valamoutopoulou,Ioannis Koutelekos
To Vima tou Asklipiou , 2009,
Abstract: The Asperger’s Syndrome is reported in the pervasive developmental disorders and was categorized as a separate disorder, initially in the ICD -10 (World Health Organization, 1992) and afterwards in the DSM-IV (American Psychiatric Organization, 1994). The Asperger’s Syndrome is distinguished by a team of symptoms that concern the low output in the social interaction and the communication dexterities, as well as the increased stereotypical behavior in various activities and interests.The aim of this particular article that constitutes a case study is the descriptive approach of the Asperger’s Syndrome, through the study of the child behavior.The methodology that was followed in the present case-study was based on inquiring studies and reviews that were drawn from international data bases that correspond to this particular case study of syndrome Asperger in children.Results: The individuals with Asperger’ s syndrome, as well as the case study, tend to experience really big difficulties in elementary social behaviors, as failure in the development and creation of friendly relations or in the search of entertainment activities with others. Moreover, they face difficulties in the comprehension of non verbal communication (body language) and the other’s expressions, the body gestures or even the eye contact.Conclusions: The precocious recognition of Asperger’s syndrome is imperative, with final objective the continuous briefing and sensitization of all health professionals, as well as the wider public, toward this syndrome. The earlier a parent foreruns for the diagnosis, the bigger probabilities they stand for a potential functional re-establishment of the syndrome.
Tissue communication in regenerative inflammatory signaling: lessons from the fly gut
Kristina Kux,Chrysoula Pitsouli
Frontiers in Cellular and Infection Microbiology , 2014, DOI: 10.3389/fcimb.2014.00049
Abstract: The intestine, as a barrier epithelium, serves in the first line of defense against invading pathogens and damaging agents that enter the body via food ingestion. Maintenance of intestinal homeostasis is therefore key to organismal health. To maintain homeostasis, intestinal stem cells (ISCs) continuously replace lost or damaged intestinal epithelial cells in organisms ranging from Drosophila to humans. Interestingly, intestinal damage upon ingestion of chemicals or pathogenic bacteria leads to an inflammatory response in the Drosophila intestine, which promotes regeneration and predisposes to tumorigenesis. This regenerative inflammatory signaling culminates in proliferation and differentiation of ISCs that replenish the damaged intestinal cells and is regulated by the interplay of conserved cell-cell communication pathways, such as the JNK, JAK/STAT, Wnt/Wingless, Notch, InR, PVR, EGFR, and Hippo. These pathways are induced by signals emanating not only from the damaged intestinal epithelial cells, but also from neighboring tissues associated with the intestinal epithelium, such as the muscles and the trachea, or distant tissues, such as the wounded epidermis and the brain. Here we review tissue communication during homeostasis and regenerative inflammatory signaling in Drosophila focusing on the signals that emanate from non-intestinal epithelial tissues to ensure intestinal integrity.
Unsaturated Keto and Exomethylene Pyranonucleoside Analogues of Thymine and Uracil Exhibit Potent Antioxidant Properties  [PDF]
Chrysoula Spanou, Niki Tzioumaki, Stella Manta, Panagiotis Margaris, Dimitrios Kouretas, Dimitri Komiotis, Kalliopi Liadaki
Pharmacology & Pharmacy (PP) , 2011, DOI: 10.4236/pp.2011.23016
Abstract: Nucleoside analogues play an important role in the development of antitumor and antiviral agents. Specific sugar modified pyranonucleosides, like the keto and exocyclic methylene nucleosides, have been studied for their biological properties, but there is little information regarding their antioxidant activity. The present study reports the antioxidant activity of a series of α,β-unsaturated 2’- or 4’ - keto and exomethylene 5’-hydroxymethyl-lacking pyranonucleosides. The antioxidant activity was evaluated using an in vitro assay which is based on the capacity to protect DNA strand scission induced by peroxyl radicals (ROO?). The majority of the tested nucleoside analogues exhibit potent antioxidant properties against ROO? radicals. We conclude that the presence of a carbon-carbon double bond at α,β-disposition to exomethylene group at position 2 of the sugar moiety and the substitution of thymine with uracil improves the antioxidant capacity of these analogues.
Total Quality Management in Hotel Restaurants: A Case Study in Greece
Chrysoula G. Lazari,Dimitris N. Kanellopoulos
Journal of Engineering and Applied Sciences , 2012,
Abstract: This study investigates the implementation of Total Quality Management (TQM) in the food and beverage departments of hotels in Achaia in Greece. TQM is a complex process that begins with an assessment of the degree of customer satisfaction and then, based on the assessment`s conclusions, determines the products and the mode of operation so that they correspond to customers` wishes. Simultaneously, they are collated, evaluated and the results dictate the corrective measures to be taken. This study also attempts to determine whether quality service is provided and it reports on the application of total TQM and Quality Certification Systems in the food and beverage departments of hotels in the prefecture of Achaia located in Greece.
The Association between Stress and Sexual Dysfunctionality in Men and Women: A Systematic Review  [PDF]
Michael Galanakis, Maria-Despoina Kallianta, Chrysoula Katsira, Dimitra Liakopoulou, P. George Chrousos, Christina Darviri
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.614186
Abstract: Purpose: Sexuality and sexual functionality are considered as an important factor of physical and psychological health. Over the years, problems with sexual functionality have been related to stress. A systematic review of the articles concerning sexual dysfunctionality is presented in this article, with emphasis in the past five years in order to highlight new aspects and implications. Method: The study was based on relevant articles from the PubMed and Wiley online library, using the combination of keywords stress and sexual dysfunctionality, while excluding articles prior to 2010. Results: The analysis shows that the phenomenon is complex and multifactorial. Variables such as depression, PTSD, lifestyle, gender, personality and positive coping play a crucial role. Research findings also indicate that sexual dysfunctionality is often misdiagnosed and not immediately taken care of. Conclusion: The severity of the pathology regarding sexual dysfunctionality calls for immediate planning and coping. Finally future research directions are discussed.
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