5,634 research outputs found

    Dynamics of Proton Transfer in Mesoscopic Clusters

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    Proton transfer rates and mechanisms are studied in mesoscopic, liquid-state, molecular clusters. The proton transfer occurs in a proton-ion complex solvated by polar molecules comprising the cluster environment. The rates and mechanisms of the reaction are studied using both adiabatic and non-adiabatic molecular dynamics. For large molecular clusters, the proton-ion complex resides primarily on the surface of the cluster or one layer of solvent molecules inside the surface. The proton transfer occurs as the complex undergoes orientational fluctuations on the cluster surface or penetrates one solvent layer into the cluster leading to solvent configurations that favor the transfer. For smaller clusters the complex resides mostly on the surface of the cluster and proton transfer is observed only when the complex penetrates the cluster and solvent configurations that favor the proton transfer are achieved. Quantitative information on the cluster reaction rate constants is also presented.Comment: To appear in JCP (March). Postscript figures available on request ([email protected]

    THE Effects of Multilateral Trade Liberalization on the Extensive and the Intensive Margins of Trade

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    This paper examines empirically the effects of the WTO and RTA membership on the extensive and the intensive margins of trade. Using disaggregated data for a sample of 177 countries, the main findings of this paper are that WTO membership tends to increase the number of products traded between members (extensive margin), and tends to increase the average sales per product line (intensive margin). I further detect substantial heterogeneity when I examine these effects for various subsamples of the data (e.g. by the degree of product differentiation or the level of development of a country). This demonstrates that many of the aggregate effects estimated in the existing literature (e.g. Rose 2004) hide a substantial amount of variation in the WTO's effect on trade. Finally, accounting for multilateral resistance as in Anderson and van Wincoop (2003), I find that the WTO effect becomes insignificant, while the RTA membership boosts trade between members and between members and outsiders at least in the aggregate level.WTO, Regional Trade Agreements, Extensive margin, Intensive Margin, Poisson Regression

    The development and evolution of transactive memory system over time in MUVEs

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    CSCW in education is a topic that drew a lot of attention over the years, and Multi User Virtual Environments (MUVEs) are one of the tools utilized by many educators to support their teaching objectives. MUVEs enable students to connect, immerse and interact with their peers and the environment, and synchronously engage and collaborate in learning activities. Effective communication and collaboration contributes to student learning, and the topic of Transactive Memory System (TMS) within working groups has been found to be very beneficial. TMS relates to the representation of the knowledge possessed by the members of a team that allows identifying who knows what, providing efficiency in collaboration. While the use of educational MUVEs has been thoroughly investigated in the literature, little is known about the use of such environments to support TMS and their relationship with working group dynamics. This paper presents the results of a study investigating the development and evolution of a TMS between groups within a MUVE, in order to better understand the dynamics that need to be considered when using MUVEs to support teaching and learning

    Υδροθερμική ανάπτυξη νανοϋλικών ZnO και μελέτη της εφαρμογής τους σε φωτοβολταϊκά κελιά σε συνδυασμό με τη μορφολογία τους

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    Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Επιστήμη και Τεχνολογία Υλικών

    The role of price and cost competitiveness for intra- and extra-euro area trade of euro area countries

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    This paper studies the importance of price and cost competitiveness for intra- and extra-euro area trade flows of euro area countries. A standard error correction framework shows that price competitiveness is a relatively more important driver of trade flows outside the euro area as compared to those within the monetary union, especially for exports, that tend to be more sensitive to relative prices than imports. We consider various measures of competitiveness and conclude that it is difficult to single out one that outperforms the others; based on an encompassing test, measures based on labour costs appear to contain relatively more information for trade flows, particularly for exports outside the euro area. The key policy implication is that to adjust competitiveness disequilibria within the monetary union, measures besides those aimed at price and cost adjustments should be pursued in the deficit countries, such as structural policies fostering non-price competitiveness

    Investigation of the possibilities harmonising National Cadastre with International Standards

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    158 σ.Η ακίνητη περιουσία από τις αρχές της σύστασης του ελληνικού κράτους αποτελεί αντικείμενο συνταγματικής κατοχύρωσης. Ο δυναμικός χαρακτήρας των μεταβολών στην ακίνητη περιουσία απαιτεί την ύπαρξη πάντα ενημερωμένων πληροφοριών σχετικά με τα δικαιώματα και τους περιορισμούς κάθε γεωτεμαχίου. Οι πληροφορίες αυτές καταγράφονται από τα κτηματολογικά συστήματα, τα οποία με την πάροδο των χρόνων εξελίσσονται και αποκτούν όλο και μεγαλύτερη σημασία. Ένα κτηματολογικό σύστημα θα πρέπει να μπορεί να ανταποκρίνεται στις απαιτήσεις του παρόντος και να προσαρμόζεται και στις τάσεις του μέλλοντος. Τα σύγχρονα κτηματολογικά συστήματα επηρεάστηκαν και συνεχίζουν να επηρεάζονται σε μεγάλο βαθμό από την εξέλιξη της τεχνολογίας των πληροφοριών και τηλεπικοινωνιών. Οι δυνατότητες των σύγχρονων συστημάτων διαχείρισης βάσεων δεδομένων και συστημάτων γεωγραφικών πληροφοριών επιτρέπουν την καλύτερη διαχείριση και διάχυση των πληροφοριών. Ωστόσο, χωρίς την ύπαρξη της τυποποίησης και διαλειτουργικότητας των συστημάτων αυτών οι δυνατότητες αυτές δεν μπορούν να αξιοποιηθούν. Για το λόγο αυτό, καταβάλλονται προσπάθειες τυποποίησης των κτηματολογικών συστημάτων, με σκοπό να βρεθούν οι κοινοί τους τόποι και να αρθούν οι γεωγραφικοί τους περιορισμοί. Το Land Administration Domain Model αποτελεί μία ολοκληρωμένη προσπάθεια τυποποίησης των κτηματολογικών συστημάτων και από την 1η Δεκεμβρίου του 2012 αποτελεί διεθνές πρότυπο (ISO 19152). Το LADM καλύπτει τις βασικές πληροφορίες που αφορούν τα συστήματα διαχείρισης της γης και είναι ένα ευέλικτο μοντέλο που μπορεί να προσαρμοστεί και να επεκταθεί σύμφωνα με τις ανάγκες της κάθε χώρας. Ταυτόχρονα, στην Ευρωπαϊκή Ένωση, η οδηγία INSPIRE έρχεται να θέσει τους κανόνες δημιουργίας της Ευρωπαϊκής Υποδομής Χωρικών Δεδομένων που θα επιτρέπει τη διασυνοριακή διάχυση των δεδομένων για τους σκοπούς της περιβαλλοντικής πολιτικής. Η κτηματολογική πληροφορία αποτελεί και εδώ σημαντική πληροφορία. Η πορεία ανάπτυξης του Εθνικού Κτηματολογίου χρονολογείται από το 1995 και μέχρι σήμερα δεν έχει ολοκληρωθεί. Πέρα από την έλλειψη κτηματολογικών πληροφοριών, η χώρα χαρακτηρίζεται και από έλλειψη μιας ολοκληρωμένης εθνικής υποδομής χωρικών δεδομένων. Η υιοθέτηση ενός προτύπου όπως το LADM θα θέσει ισχυρότερα θεμέλια στον θεσμό του Κτηματολογίου, ενώ η εναρμόνιση της βάσης δεδομένων του με τα κτηματολογικά γεωτεμάχια της INSPIRE θα αποτελέσει πυρήνα ανάπτυξης της υποδομής χωρικών δεδομένων για την Ελλάδα.Since the establishment of the Greek State, immovable property is protected by the Greek Constitution. The dynamic nature of immovable property calls for updated information about rights and restrictions that apply to each land parcel. All this information is recorded by the cadastral systems, which have evolved over the years gaining an even bigger importance in today’s life. Modern cadastral systems were affected and continue to be strongly affected by the advancements in Information and Communications Technology. The capabilities of modern DBMS (Database Management Systems) and GIS (Geographic Information Systems) allow for more effective management and dissemination of information. However, those capabilities cannot be fully exploited due the absence of standardisation and interoperability within cadastral systems. Thus, standardisation efforts are being made in the land administration domain so that a common denominator is found between those systems and geographic constraints are removed. The Land Administration Domain Model is an incremental approach to standardise cadastral systems and since 1st of December 2012 is an international standard, ISO 19152. LADM covers basic information related to components of land administration and is a flexible model which can be easily adapted to local needs. At the same time, in the European Union, INSPIRE Directive sets the rules for the implementation of European Spatial Data Infrastructure, which will enable the cross border dissemination of data initially for the purposes of environmental policy. Cadastral information plays an important role here, too. The development of the Hellenic Cadastre dates back to 1995 and has yet to be completed. Apart from cadastral information shortage, the country has to deal with the absence of an integrated national spatial data infrastructure. The implementation of a standard like the LADM will set more robust foundations for the completion of the Hellenic Cadastre, while harmonization with INSPIRE’s Cadastral Parcels will become the driver for the creation of SDI in Greece.Στυλιανή Γ. Ψωμαδάκ
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