865 research outputs found
Wage Mobility in Europe. A Comparative Analysis Using restricted Multinomial Logit Regression
In this paper, we investigate cross-country differences in wage mobility in Europe using the European Community Household Panel. The paper is particularly focused on examining the impact of economic conditions, welfare state regimes and employment regulation on wage mobility. We apply a log-linear approach that is very much similar to a restricted multinomial logit model and much more flexible than the standard probit approach. It appears that regime, economic conditions and employment regulation explain a substantial part of the cross-country variation. The findings also confirm the existence of an inverse U-shape pattern of wage mobility, showing a great deal of low and high-wage persistence in all countries.wages; wage mobility; wage dynamics; multinomial logit regression; loglinear models; welfare states
Who benefits from a job change: The dwarfs or the giants?
Empirical studies have shown that voluntary job-to-job changes have a positive effect on wage mobility. In this paper, we suggest that the impact of a job change on wage growth depends on the position in the wage distribution. Using panel data from the UK and Germany, we investigate the effect of employer changes and within-firm job changes on year-to-year wage mobility. We show that a change of employer results into a wage increase for the low-paid workers but not for the high-paid workers. Within-firm job changes produce, on average, moderate wage gains for the low-paid workers in the UK, but have no effect in Germany. Results on 3-year wage mobility are shown to be very similar to the results on year-to-year wage growth.low pay ; high pay ; job mobility ; wage mobility
Geomorphological mapping of Messogia plain (East Attica, Greece).
Η παρούσα μελέτη αφορά τη γεωμορφολογική χαρτογράφηση της περιοχής που περιλαμβάνεται στα φύλλα χάρτη Κορωπί και Πλάκα της διανομής της Γ.Υ.Σ. σε κλίμακα 1:50.000 . Πρόκειται για μια εκτεταμένη περιοχή της Ανατολικής Αττικής η οποία παρουσιάζει σύνθετο ανάγλυφο και μεγάλη ποικιλία γεωμορφών, λόγω του έντονου τεκτονισμού της και των φυσικών διεργασιών που διαμόρφωσαν τη μορφολογία της. Για τη δημιουργία του χάρτη χρησιμοποιήθηκαν κυρίως γεωλογικοί και τοπογραφικοί χάρτες, από τους οποίους κατασκευάστηκαν μέσω Γεωγραφικών Συστημάτων Πληροφοριών τα θεματικά επίπεδα της τοπογραφίας, της υδρογραφίας και της γεωλογίας, ενώ κατασκευάστηκε επίσης και το Ψηφιακό Μοντέλο Εδάφους, από το οποίο προέκυψαν οι χάρτες κλίσεων και έκθεσης. Οι θεματικοί χάρτες των κλίσεων και της λιθολογίας ταξινομήθηκαν σε κατηγορίες οι οποίες συνδυάστηκαν αποτελώντας κριτήρια εντοπισμού γεωμορφών. Στη χαρτογράφηση συνέβαλλαν καθοριστικά οι διαθέσιμοι ορθοφωτοχάρτες και αεροφωτογραφίες, όπως επίσης η εργασία πεδίου. Στη συνέχεια, με τον κατάλληλο συνδυασμό χρωμάτων και συμβολισμών δημιουργήθηκε ο γεωμορφολογικός χάρτης της περιοχής μελέτης, η οποία αποτελείται από τμήματα διαφοροποιημένων μορφολογικών χαρακτηριστικών του αναγλύφου.This study concerns the geomorphological mapping of the area included in the map sheets Koropi and Plaka of the Hellenic Military Geographical Service map distribution in scale 1:50.000. This is an extensive area of East Attica which presents a complex terrain and a wide variety of landforms, due to its intense tectonism and the natural processes that shaped its morphology. The primary data that were used in the creation of the map mainly included geological and topographic maps, from which thematic layers of the topography, hydrography and geology were constructed through GIS processes. A Digital Elevation Model was also constructed, from which the slope and aspect maps were created. The thematic maps of slοpe and lithology were classified into categories, which were combined to constitute detection criteria of landforms. Decisive contribution in mapping was provided by the available orthophotomaps and aerial photographs, as well as the field work. Finally, with the appropriate combination of colors and symbols the geomorphological map of the study area was produced
Inflation in supergravity with non-minimal superpotentials
We investigate the cosmological inflation in a class of supergravity models
that are generalizations of non-supersymmetric models. Although such
models have been extensively studied recently, especially after the launch of
the PLANCK and BICEP2 data, the class of models that can be constructed has not
been exhausted. In this note, working in a supergravity model that is a
generalization of Cecotti's model, we show that the appearance of new
superpotential terms, which are quadratic in the superfield that
couples to the Ricci supermultiplet, alters substantially the form of the
scalar potential. The arising potential has the form of the Starobinsky
potential times a factor that is exponential in the inflaton field and
dominates for large inflaton values. We show that the well-known Starobinsky
inflation scenario is maintained only for unnaturally small fine-tuned values
of the coupling describing the superpotential terms. A welcome
feature is the possible increase of the tensor to scalar ratio , within the
limits set by the new Planck and BICEP2 data.Comment: 13 pages, 9 figures, text and references added, version submitted to
Phys. Lett.
KARSTIC LANDSCAPE STUDY BASED ON REMOTE SENSING DATA: THE CASE OF KSIROMERO REGION, AITOLOAKARNANIA - WESTERN GREECE
The aim of this study is to investigate and recognize karst landforms in the area of Ksiromero (Aitoloakarnania, Western Greece) based on medium resolution remote sensing data. In order to highlight karstic structures appropriate and innovative methodologies of image analysis have been developed, applied and compared. In particular, the original Landsat 5 TM bands have been, first, ad-hoc stretched and then processed to obtain the so-called Tasseled Cap Features and the Principal Component images. Finally, a comparative study between the two methods has been carried out
Lost in translation: data integration tools meet the Semantic Web (experiences from the Ondex project)
More information is now being published in machine processable form on the
web and, as de-facto distributed knowledge bases are materializing, partly
encouraged by the vision of the Semantic Web, the focus is shifting from the
publication of this information to its consumption. Platforms for data
integration, visualization and analysis that are based on a graph
representation of information appear first candidates to be consumers of
web-based information that is readily expressible as graphs. The question is
whether the adoption of these platforms to information available on the
Semantic Web requires some adaptation of their data structures and semantics.
Ondex is a network-based data integration, analysis and visualization platform
which has been developed in a Life Sciences context. A number of features,
including semantic annotation via ontologies and an attention to provenance and
evidence, make this an ideal candidate to consume Semantic Web information, as
well as a prototype for the application of network analysis tools in this
context. By analyzing the Ondex data structure and its usage, we have found a
set of discrepancies and errors arising from the semantic mismatch between a
procedural approach to network analysis and the implications of a web-based
representation of information. We report in the paper on the simple methodology
that we have adopted to conduct such analysis, and on issues that we have found
which may be relevant for a range of similar platformsComment: Presented at DEIT, Data Engineering and Internet Technology, 2011
IEEE: CFP1113L-CD
GIS as an educational tool: Mapping cultural sites in greek space-time
Το θέμα της παρούσας εργασίας είναι η χαρτογραφική παρουσίαση της πολιτιστικής διαδοχής στον ελληνικό χωρο-χρόνο που σχετίζεται με βασικές έννοιες της γεωγραφικής και ιστορικής εκπαίδευσης. Η παιδαγωγική αξία της μελέτης είναι η ανάπτυξη πέντε διακριτών δεξιότητων: της έννοιας του χρόνου-κλίμακας, της ιστορικής και γεωγραφικής κατανόησης, της χωρικής ανάλυσης και ερμηνείας, της ικανότητας διεξαγωγής γεω-ιστορικής έρευνας, και της γεω-ιστορικής διαδικασίας λήψης αποφάσεων. Η μεθοδολογία βασίζεται στη βαθμονόμηση μιας σειράς κριτηρίων για κάθε πολιτιστική περιοχή που καλύπτει τα θέματα της οικονομίας, της γεωμορφολογίας, της κοινωνίας των πολιτών, της θρησκείας, της τέχνης και της επιστήμης. Η περαιτέρω ανάλυση αυτών των δεδομένων οδηγεί στη δημιουργία μιας γεω-βάσης. Οι παλαιογεωγραφικοί και ιστορικοί χάρτες των πολιτιστικών χώρων που προέρχονται από την γεωβάση παρέχουν πληροφορίες σχετικά με τις χρονικές και χωρικές μεταβολές. Ως αποτέλεσμα, οι μαθητές θα είναι σε θέση να αναπτύξουν μια πολυδιάστατη και διεπιστημονική προσέγγιση, προκειμένου να ανακατασκευάσουν την εξέλιξη του τόπου.This paper deals with the cartographical presentation of cultural succession in Greek space-time associated with core concepts of geographic and historical education. The pedagogic value of this study is to develop five distinct skills: sense of time-scale, historical and geographic comprehension, spatial analysis and interpretation, ability to perform geo-historical research, and procedure of geohistorical decision-making. The methodology is based on the calibration of a set of criteria for each cultural site that covers the topics of economy, geomorphology, society, religion, art and science. Further analysis of these data forms a geodatabase. In addition, palaeogeographic and historical maps of the cultural sites derived by the geodatabase provide information about temporal and spatial changes. As result, students will be able to develop a multidimensional and interdisciplinary approach, in order to reconstruct the evolution of the site
Geologic environments for nuclear waste repositories
© The Authors, published by EDP Sciences, 2017. High-level radioactive waste (HLW) results from spent reactor fuel and reprocessed nuclear material. Since 1957 the scientific consensus is that deep geologic disposal constitutes the safest means for isolating HLW for long timescales. Nuclear power is becoming significant for the Arab Gulf countries as a way to diversify energy sources and drive economic developments. Hence, it is of interest to the UAE to examine the geologic environments currently considered internationally to guide site selection. Sweden and Finland are proceeding with deep underground repositories mined in bedrock at depths of 500m, and 400m, respectively. Equally, Canada\u27s proposals are deep burial in the plutonic rock masses of the Canadian Shield. Denmark and Switzerland are considering disposal of their relative small quantities of HLW into crystalline basement rocks through boreholes at depths of 5,000m. In USA, the potential repository at Yucca Mountain, Nevada lies at a depth of 300m in unsaturated layers of welded volcanic tuffs. Disposal of low and intermediate-level radioactive wastes, as well as the German HLW repository favour structurally-sound layered salt stata and domes. Our article provides a comprehensive review of the current concepts regarding HLW disposal together with some preliminary analysis of potentially appropriate geologic environments in the UAE
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