140 research outputs found
Remodeling effects of carotid artery stenting versus endarterectomy with patch angioplasty in terms of morphology and hemodynamics
No full textBackground: Carotid endarterectomy (CEA) remains the first-line treatment option of symptomatic and asymptomatic carotid stenosis, while stenting (CAS) is reserved for selected patients at high surgical risk. Here, we compare the vascular remodeling process in CEA-and CAS-treated patients with respect to morphological and hemodynamic features, because of their possible engagement in carotid atherosclerosis. Methods: Twelve (12) patients were included, half with patched CEA and half with CAS. Pre-and post-operative 3D image-based models of the carotid bifurcation were anatomically characterized in terms of flare, tortuosity, and curvature. Individual computational fluid dynamics simulations allowed to quantify the postoperative hemodynamic milieu in terms of (1) wall shear stress and (2) helical flow. Results: Carotid flare increased in all cases, but a more marked increase emerged after CEA compared to CAS. Tortuosity and curvature increased after CEA but decreased after CAS. CEA patients presented with significantly higher postoperative tortuosity than CAS patients. CEA was associated with a worse (non-statistically significant) score in all flow disturbance indicators vs. CAS. Conclusion: The increased flare and tortuosity of the carotid bifurcation after CEA vs. CAS is a marked difference in the vascular remodeling process between the two modalities. CAS seems to induce a less pro-restenosis hemodynamic environment compared to CEA. The emerged differences stimulate further analysis on a larger cohort with long-term outcomes, to shed light on the clinical impact of the observations
Carotid artery endarterectomy vs. stenting: are there any relevant morphological and hemodynamic implications?
Get PDFCONFIRMATORY FACTOR ANALYSIS AND ESTIMATOR COMPARISON OF TWO SHORT FORMS OF AN IRRATIONAL AND RATIONAL BELIEFS SCALE Author(s): Joanne Raptis
Get PDFThe present study examined two abbreviated versions of the Attitudes and Beliefs Scale-2 (ABS-2) to compare their factor structure and ability to achieve model fit to the data. The original scale, a measure of irrational and rational beliefs as defined by REBT theory, was designed with 72 items reflecting irrational and rational beliefs and each involving one of four cognitive processes and one of three content areas. The ABS-2 had been criticized for its length and the inconsistency of findings regarding its factor structure. Two groups of researchers independently created short forms of the ABS-2 using 24 of the original items. One scale used the items with the highest factor loadings, while the other also prioritized maintaining balance across all dimensions. To also explore the effects of using different estimators, the authors ran Confirmatory Factor Analyses (CFAs) for each short form twice, once using the Maximum Likelihood Robust (MLR) estimator and once using Diagonally Weighted Least Squares (DWLS). The sample consisted of over 1500 participants that included university students, psychotherapy outpatients, and individuals in a drug rehabilitation program. Results showed that both scales yielded virtually equal and excellent fit indices when using the DWLS estimator but not when using MLR. The model with the best fit was an eight-factor bifactor model with factors for the irrational and rational cognitive processes and a general factor. Two other models also yielded especially excellent fit, including a two-factor bifactor model for irrationality and rationality as well as a second-order model with items loading on either one of the four irrational cognitive processes and then a second-order irrationality factor or on one of the four rational cognitive processes and a second-order rationality factor. Ultimately, the results suggest that the assessment can provide meaningful subscales for scores of the total, irrationality, rationality, cognitive processes, and content domains. Additionally, the findings highlight the importance of critically considering one’s data and selecting an appropriate estimator as opposed to relying on default settings. Implications for the assessment of irrational and rational beliefs, furthering REBT research, and targeting treatment to client presentation across the three dimensions are discussed
Finitary Čech-de Rham cohomology
No full textThe present paper continues (Mallios & Rapfis, International Journal of Theoretical Physics, 2001, 40, 1885) and studies the curved finitary spacetime sheaves of incidence algebras presented therein from a Čech cohomological perspective. In particular, we entertain the possibility of constructing a nontrivial de Rham complex on these finite dimensional algebra sheaves along the lines of the first author's axiomatic approach to differential geometry via the theory of vector and algebra sheaves (Mallios, Geometry of Vector Sheaves. An Axiomtic Approach to Differential Geometry, Vols. 1-2, Kluwer, Dordrecht, 1998a; Mathematica Japonica (International Plaza), 1998b, 48, 93). The upshot of this study is that important "classical" differential geometric constructions and results usually thought of as being intimately associated with C∞-smooth manifolds carry through, virtually unaltered, to the finitary-algebraic regime with the help of some quite universal, because abstract, ideas taken mainly from sheaf-cohomology as developed in Mallios (1998a,b). At the end of the paper, and due to the fact that the incidence algebras involved have been interpreted as quantum causal sets (Raptis, International Journal of Theoretical Physics, 2000, 39, 1233; Mallios & Rapfis, 2001), we discuss how these ideas may be used in certain aspects of current research on discrete Lorentzian quantum gravity
the case of rectorial team
No full textΒιβλιογραφία: σ. 485-532To διοικητικό και ηγετικό έργο των Πρυτανικών Αρχών (Π.Α.) των ελληνικών πανεπιστημίων συνιστά ένα κρίσιμης σημασίας ζήτημα, δεδομένης της σπουδαιότητας των ίδιων των πανεπιστημίων, και ταυτόχρονα ένα επίκαιρο και δύσκολο θέμα, δεδομένων των σύγχρονων εξελίξεων που επισυμβαίνουν διεθνώς στον χώρο της ανώτατης εκπαίδευσης και της πολυπλοκότητας που χαρακτηρίζει το ίδιο το έργο αντίστοιχα. Μάλιστα, στο πλαίσιο του μεταβαλλόμενου τοπίου που έχει διαμορφωθεί για τα πανεπιστήμια υπό το φως των ραγδαίων σύγχρονων εξελίξεων, σοβαρές ενστάσεις εγείρονται για την τάση που παρατηρείται διεθνώς να ισχυροποιείται ο ρόλος των ανώτατων πανεπιστημιακών διοικούντων και να υποστηρίζεται η ανάγκη για άσκηση ισχυρής διοίκησης και ηγεσίας στα πανεπιστήμια, προκειμένου αυτά να προσαρμοστούν στα νέα δεδομένα, με τις ενστάσεις αυτές να εδράζονται στην ιδιαίτερη φύση των πανεπιστημιακών οργανώσεων, ένα ζήτημα που είναι, πάντως, ανοιχτό στο σχετικό ερευνητικό πεδίο. Παράλληλα, το έργο που επιτελεί η ηγέτιδα ομάδα των πανεπιστημίων αποτελεί μέχρι και σήμερα μια παραμελημένη θεματική, τόσο στην ελληνόγλωσση όσο και στην ξενόγλωσση βιβλιογραφία. Σκοπός, λοιπόν, της παρούσας διατριβής ήταν να διερευνηθούν, κατά το δυνατόν, πολύπτυχα και σε βάθος το ατομικό διοικητικό έργο του Πρύτανη και του Αντιπρύτανη, καθώς και το έργο που ασκούν συλλογικά ως Π.Α., όπως επίσης και τα καίρια ζητήματα που αφορούν τα υπό διερεύνηση αξιώματα (π.χ. τρόπος εκλογής, εκλέκτορες, θητεία), με στόχο παράλληλα να διαπιστωθεί εάν πράγματι η διοίκηση και η ηγεσία στα πανεπιστήμια είναι ιδιάζουσες. Για την επίτευξη του παραπάνω σκοπού διεξήχθησαν 15 συνεντεύξεις-ελίτ σε δείγμα Πρυτάνεων και Αντιπρυτάνεων που διατελούσαν στις υπό εξέταση θέσεις σε διάφορα ελληνικά πανεπιστήμια και σε διαφορετικά χρονικά διαστήματα. Η ανάλυση των ερευνητικών δεδομένων επέφερε έναν πλούτο πρωτογενών στοιχείων, που μπορούν να φανούν χρήσιμα στους ιθύνοντες της εκπαιδευτικής πολιτικής, στους μελλοντικούς ερευνητές, αλλά και σε όσους ασκούν ή επιθυμούν να ασκήσουν διοίκηση και ηγεσία στο ανώτατο επίπεδο των πανεπιστημίων. Στα γενικά συμπεράσματα στα οποία καταλήγει η παρούσα διατριβή ανήκει η ενδεχομενικότητα της άσκησης του έργου των Π.Α. και της παραγωγής αποτελεσμάτων, λόγω μιας σειράς δυναμικών παραγόντων που το επηρεάζουν, οι οποίοι εξηγούνται και απορρέουν από την ιδιαίτερη και ιδιάζουσα φύση των πανεπιστημιακών οργανώσεων.Management and leadership conducted by Rectorial Teams in Greek universities are a critical issue, given the importance of universities themselves, as well as a topical and challenging matter, given not only the current developments and challenges in the international context of higher education but also the complexity of the aforementioned work itself. In fact, in the context of the changing landscape under which universities must function, a global trend is being observed toward strengthening senior university administrators’ role and institutional management and leadership in universities, nevertheless, serious concerns have been raised over this trend. The objections echo the peculiar nature of university organizations, although the latter remains unclear in higher education research. At the same time, the work performed by senior administrative teams in universities is up to now a neglected research topic, both in Greek and in foreign literature. Hence, the purpose of this doctoral dissertation was to explore in detail and depth, as much as possible: a) the Rector’s and Vice-rector’s managerial work, b) the work carried out collectively by the Rectorial Team, as well as c) the key issues concerning the under-investigation Offices (e.g., election model, electors, term in Office). Still, the dissertation also sought to explore whether management and leadership in universities are indeed distinctive. For the research purpose to be met, 15 elite interviews were conducted with a sample of Rectors and Vice-rectors serving in these positions in diverse Greek universities and different periods. The analysis of the research data brought a wealth of primary findings, which may be of interest to those in charge of the educational policy’s formulation, to aspiring researchers, as well as to those exercising or wish to exercise management and leadership at the universities’ top. The contingency surrounding the Rectorial Teams’ managerial work lay among the general conclusions drawn from the study, which was explained by a series of dynamic factors concerning the peculiar nature of universities as organizations.535 σ
'Third' quantization of vacuum Einstein gravity and free Yang-Mills theories
No full textCertain pivotal results from various applications of Abstract Differential Geometry (ADG) to gravity and gauge theories are presently collected and used to argue that we already possess a geometrically (pre)quantized, second quantized and manifestly background spacetime manifold independent vacuum Einstein gravitational field dynamics. The arguments carry also mutatis mutandis to the case of free Yang-Mills theories, since from the ADG-theoretic perspective gravity is regarded as another gauge field theory. The powerful algebraico-categorical, sheaf cohomological conceptual and technical machinery of ADG is then employed, based on the fundamental ADG-theoretic conception of a field as a pair (ε D) consisting of a vector sheaf ε and an algebraic connection D acting categorically as a sheaf morphism on ε 's local sections, to introduce a 'universal', because expressly functorial, field quantization scenario coined third quantization. Although third quantization is fully covariant, on intuitive and heuristic grounds alone it formally appears to follow a canonical route; albeit, in a purely algebraic and, in contradistinction to geometric (pre)quantization and (canonical) second quantization, manifestly background geometrical spacetime manifold independent fashion, as befits ADG. All in all, from the ADG-theoretic vantage, vacuum Einstein gravity and free Yang-Mills theories are regarded as external spacetime manifold unconstrained, third quantized, pure gauge field theories. The paper abounds with philosophical smatterings and speculative remarks about the potential import and significance of our results to current and future Quantum Gravity research. A postscript gives a brief account of this author's personal encounters with Rafael Sorkin and his work. © Springer Science+Business Media, LLC 2007
Thyroid hormones are positively associated with insulin resistance early in the development of type 2 diabetes
No full textWhat the radiologist needs to know about the diabetic patient
No full textAbstract
Diabetes mellitus (DM) is recognised as a major health problem. Ninety-nine percent of diabetics suffer from type 2 DM and 10% from type 1 and other types of DM. The number of diabetic patients worldwide is expected to reach 380 millions over the next 15 years. The duration of diabetes is an important factor in the pathogenesis of complications, but other factors frequently coexisting with type 2 DM, such as hypertension, obesity and dyslipidaemia, also contribute to the development of diabetic angiopathy. Microvascular complications include retinopathy, nephropathy and neuropathy. Macroangiopathy mainly affects coronary arteries, carotid arteries and arteries of the lower extremities. Eighty percent of deaths in the diabetic population result from cardiovascular incidents. DM is considered an equivalent of coronary heart disease (CHD). Stroke and peripheral artery disease (PAD) are other main manifestations of diabetic macroangiopathy. Diabetic cardiomyopathy (DC) represents another chronic complication that occurs independently of CHD and hypertension. The greater susceptibility of diabetic patients to infections completes the spectrum of the main consequences of DM. The serious complications of DM make it essential for physicians to be aware of the screening guidelines, allowing for earlier patient diagnosis and treatment.</jats:p
Dietary Composition and Cardiovascular Risk: A Mediator or a Bystander?
No full textThe role of nutrition in the pathogenesis of cardiovascular disease has long been debated. The established notion of the deleterious effects of fat is recently under question, with numerous studies demonstrating the benefits of low-carbohydrate, high-fat diets in terms of obesity, diabetes, dyslipidemia, and metabolic derangement. Monounsaturated and polyunsaturated fatty acids, especially n-3 PUFAs (polyunsaturated fatty acids), are the types of fat that favor metabolic markers and are key components of the Mediterranean Diet, which is considered an ideal dietary pattern with great cardioprotective effects. Except for macronutrients, however, micronutrients like polyphenols, carotenoids, and vitamins act on molecular pathways that affect oxidative stress, endothelial function, and lipid and glucose homeostasis. In relation to these metabolic markers, the human gut microbiome is constantly revealed, with its composition being altered by even small dietary changes and different microbial populations being associated with adverse cardiovascular outcomes, thus becoming the target for potential new treatment interventions. This review aims to present the most recent data concerning different dietary patterns at both the macro- and micronutrient level and their association with atherosclerosis, obesity, and other risk factors for cardiovascular disease
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