Renormalization-group improved fully differential cross sections for top pair production

We extend approximate next-to-next-to-leading order results for top-pair production to include the semi-leptonic decays of top quarks in the narrow-width approximation. The new hard-scattering kernels are implemented in a fully differential parton-level Monte Carlo that allows for the study of any IR-safe observable constructed from the momenta of the decay products of the top. Our best predictions are given by approximate NNLO corrections in the production matched to a fixed order calculation with NLO corrections in both the production and decay subprocesses. Being fully differential enables us to make comparisons between approximate results derived via different (PIM and 1PI) kinematics for arbitrary distributions. These comparisons reveal that the renormalization-group framework, from which the approximate results are derived, is rather robust in the sense that applying a realistic error estimate allows us to obtain a reliable prediction with a reduced theoretical error for generic observables and analysis cuts

Online sports betting in Greece : an empirical investigation

Although international interest on e-gambling commerce is steadily increasing, studies about the online sports betting sector in Greece are very rare. Based on a web survey the present study, attempts to address this gap, by shedding light on the active sports bettors characteristics, preferences and patterns in Greece. A thorough analysis of 325 internet sport bettors reveals contingent relations between significant variables, while conclusions are drawn about the size of stakes placed and the punters motivations.peer-reviewe

Improving route discovery in on-demand routing protocols using local topology information in MANETs

Most existing routing protocols proposed for MANETs use flooding as a broadcast technique for the propagation of network control packets; a particular example of this is the dissemination of route requests (RREQs), which facilitate route discovery. In flooding, each mobile node rebroadcasts received packets, which, in this manner, are propagated network-wide with considerable overhead. This paper improves on the performance of existing routing protocols by reducing the communication overhead incurred during the route discovery process by implementing a new broadcast algorithm called the adjusted probabilistic flooding on the Ad-Hoc on Demand Distance Vector (AODV) protocol. AODV [3] is a well-known and widely studied algorithm which has been shown over the past few years to maintain an overall lower routing overhead compared to traditional proactive schemes, even though it uses flooding to propagate RREQs. Our results, as presented in this paper, reveal that equipping AODV with fixed and adjusted probabilistic flooding, instead, helps reduce the overhead of the route discovery process whilst maintaining comparable performance levels in terms of saved rebroadcasts and reachability as achieved by conventional AODV\@. Moreover, the results indicate that the adjusted probabilistic technique results in better performance compared to the fixed one for both of these metrics

Austerity and fuel consumption in Greece : an empirical investigation

Greek economic crisis in the last years and the subsequent austerity policy measures resulted to a decline in consumers’ income. This paper investigates empirically the Greek consumers’ reactions to income changes regarding their consumption of different types of fuels during the period 2007-2011. The empirical findings suggest that fuel consumption elasticity of income is different among different types of fuels. Furthermore the income elasticity is different among different Greek geographic regions. More specifically, fuels with high consumption i.e. 95 RON unleaded gasoline and diesel-bio fuels are found to be income inelastic as compared to fuels with low consumption i.e. 98-100 RON unleaded gasoline and new super gasoline LRP. Furthermore, for the high consumed fuels, consumers’ behavior patterns to income changes in the island are opposite to that in the rest Greek territory.peer-reviewe

Comparative geomorphological observations in two groups of alluvial fans of Sperchios and Eurotas regions, Greece

Στην παρούσα εργασία μελετήθηκαν συγκριτικά δύο ομάδες αλλουβιακών ριπιδίων του ελληνικού χώρου, η πρώτη στην περιοχή του ποταμού Σπερχειού και η δεύτερη στην περιοχή του ποταμού Ευρώτα. Fia το σκοπό αυτό μετρήθηκαν συγκεκριμένα μορφομετρικά χαρακτηριστικά των λεκανών απορροής των ρεμάτων Τσερλιά, Ξεριά, Γοργοπόταμου, Κερασιά, Ρέτσα και Κάκαρη, καθώς και των ριπιδίων τους, έγινε σύγκριση των μετρήσεων αυτών και βγήκαν συμπεράσματα για το σχηματισμό και την εξέλιξη των ριπιδίων. Παράλληλα έγιναν επιμήκεις τομές της κεντρικής κοίτης των ρεμάτων, πραγματοποιήθηκε κροκαλομετρία εντός της κοίτης των ριπιδίων και αποτυπώθηκαν οι οδοντώσεις των ισοϋψών των ριπιδίων. Κατά την κροκαλομετρία έγινε φανερό ότι το μέσο μέγεθος Μ μειώνεται από την κορυφή προς τη βάση των ριπιδίων. Από τη μελέτη των οδοντώσεων των ισοϋψών προέκυψε ότι τα ριπίδια στην περιοχή του Ευρώτα έχουν υποστεί μεγαλύτερη διάβρωση από αυτά της περιοχής του Σπερχειού. Απ' όλα τα παραπάνω συμπεραίνεται ότι τα μελετούμενα ριπίδια παρουσιάζουν σημαντικές διαφορές τόσο μεταξύ τους (κυρίως για την περιοχή του Σπερχειού) όσο και μεταξύ των δύο περιοχών μελέτης. Αυτό οφε^ται κυρίως στον ρηξιγενή τεκτονισμό, την επικρατούσα λιθολογία και το κλίμα. Οι παράγοντες αυτοί είναι εκείνοι που κυρίως καθορίζουν τη γένεση και εξέλιξη των ριπιδίων και επηρεάζουν το σχήμα, την έκταση και τα επιμέρους χαρακτηριστικά τουςIn the present study two groups of alluvial fans from two different regions in Greece were comparetively studied, the first in the region of Sperchios river and the second in the region ofEurotas river. Distinct morphometric characteristics of the drainage basins of the tributaries Ts er lias, Xerias, Gorgopotamos, Kerasias, Retsas and Kakaris, as well as their fans were measured and compared. Furthermore ,the longitudinal stream profiles were mapped, pebble measurements were made and contour crenulations of the fans were studied. In gravelometry, it was found that the mean size M of the pebbles decreases from the apex to the apron of the fan. The crenulation analysis showed that the fans of the streams ofEurotas region have undergone greater erosion than those of Sperchios region. Remarkable differences exist between the fans of the two regions. These results lead to the conclusion that recent tectonism, the prevailing lithology and climate are responsible for the formation and evolution of the fans and also influence their shape, area and all the other morphometric characteristic

Factorised spatial representation learning: application in semi-supervised myocardial segmentation

The success and generalisation of deep learning algorithms heavily depend on learning good feature representations. In medical imaging this entails representing anatomical information, as well as properties related to the specific imaging setting. Anatomical information is required to perform further analysis, whereas imaging information is key to disentangle scanner variability and potential artefacts. The ability to factorise these would allow for training algorithms only on the relevant information according to the task. To date, such factorisation has not been attempted. In this paper, we propose a methodology of latent space factorisation relying on the cycle-consistency principle. As an example application, we consider cardiac MR segmentation, where we separate information related to the myocardium from other features related to imaging and surrounding substructures. We demonstrate the proposed method's utility in a semi-supervised setting: we use very few labelled images together with many unlabelled images to train a myocardium segmentation neural network. Specifically, we achieve comparable performance to fully supervised networks using a fraction of labelled images in experiments on ACDC and a dataset from Edinburgh Imaging Facility QMRI. Code will be made available at https://github.com/agis85/spatial_factorisation.Comment: Accepted in MICCAI 201

Burden sharing in NATO

During the period of cold war, NATO alliance was producing defence commodity to protect its members from the common threat of ex-Soviet Union. The paper examines the problem of burden sharing among NATO allies. It is shown that larger countries are benefited more than smaller countries from the production of the public good i.e defence, if the income elasticity of marginal utility of income is greater than one in absolute value. Complete demand systems are employed for estimating the income elasticity of marginal utility of income.peer-reviewe

Tourists’ satisfaction and revisiting : an investigation of causality effects

In this paper, a switching regime model with known sample separation is applied to Greek data, to investigate causality linkages between tourists' satisfaction and their willingness for revisiting. The empirical evidence shows the existence of these causality effects. Moreover, it shows that the willingness for revisiting crucially depends on many qualitative aspects of tourist services and accommodation.peer-reviewe