60 research outputs found
Informal Forms of Work and the Fragmentation of Local Labour Markets: The Case of Part–Time Work in Greece
Employment facts constantly change. It is a common ascertainment among a large portion of researchers that changes in productive and regulatory patterns are followed by an expansion of informal and flexible forms of work. Reasonably enough, a series of questions arise regarding the causes and rates of expansion of flexible forms of work; their relation to traditional informal work; their complementary or expansive to the detriment of formal work; their association with choices made by enterprises and with the overall concept of “new economyâ€. Speculation is also developed as to whether flexible employment contracts may be in line with quality employment and, what is more, consciously selected. The answers to such questions are not one-way, given the lack of reliable statistics throughout the range of production and consumer activities, as well as the diverse views on the opportunities and risks, advantages and disadvantages, of recent changes. For instance, some see the transition to more flexible employment patterns as an indication of economy restructuring and blooming, while others view it as new management strategy that deepens work fragmentation. In this paper, we underscore that the study of informal or non-standard forms of work require the review of the social-economic dimensions and features of this phenomenon, in close connection with geographic parameters. In this context, focusing on the level of local labour markets through theoretically informed empirical research has much to offer, at least in the manner it is attempted in the following pages on Thessaloniki’s urban industrial agglomeration, in Greece. The need for locally specified research, given the lack of statistical data with small spatial reference unit and systematic elaboration on macroeconomic nation-wide data sources, may help considerably in understanding the new reality. By means of such a methodological approach, changes around labour, informal work and, specifically part-time work, in cities and regions, and the overall effects of production restructuring on residence and work areas will be analysed in depth and from a different point of view. The overall primary -and non-primary- material assembled leads to the conclusion that the indisputable expansive trend of informal labour and “part-timers†in the “post-Fordist†era is not a homogenous, dominant reality; it rather varies significantly among the individual population groups, trades, sectors, restructuring strategies and, finally, among local labour realities.
Development of Geographical Information Systems Applications for Local Government Organizations: the Case of the Rhodes Municipality, Greece
The present recommendation summons up matter from a project in progress, concerning the possibilities and conditions of founding a Social Geographical Information System (GIS) in the Municipality of Rhodes. It is argued that, on the level of local societies and their self-administration, the importance of GIS can prove decisive for the rational management of resources and mainly for a better service of the citizens. Local governments, being that very institution at the closest possible relationship and contact with the resident-citizen, are called to cope with a constantly expanding spectrum of functions and services, often with insufficient infrastructures and limited resources. Today’s stage of the applied development of the GIS technology permits an overall arrangement and regulation of a series of functions that are important elements of everyday life in a city. In this sense, the use of GIS, although in the beginning seems as an “unnecessary luxury†for Greek administrational matters, can contribute in a creative way to the realization of the institutional role of local government organizations, to the accomplishment of the declared goals of each municipal authority but also to the saving of time and expenses. However, beyond the applications of GIS related to the improvement of a city’s functions, and which are the most frequent, there is a whole constellation of additional uses that are often downgraded or ignored. It is about those dimensions and applications, during which the GIS are utilized as an implement of social studies and search, as a mechanism of tendency diagnosis, as a starting point for awareness on the problems of urban areas and of their residents. It is the perspective and necessity of such applications that we are trying not to downgrade in the present, initial stage of development of a “Social GIS for the Municipality of Rhodesâ€. Our fundamental point of view is that no modern “leading-edge†technology, no advanced implement is by itself a panacea. It can simply assist the development procedures, when it is in the right hands and with the appropriate staff, information and infrastructure. Procedures that have finally reference to the level of central or local political choices but also to the disposition, dynamic or not dynamic, of the body politic for interference and action.
Which acceleration process for UHE-Cosmic Rays in Gamma Ray Bursts ?
In this paper, we have made an accurate investigation of proton acceleration
in GRBs and we have predicted a possible signature of cosmic rays, in a
sufficiently baryon-loaded fireball, via GeV -ray emission produced by
-meson decay. If two ungrounded assumptions are removed, namely,
Bohm's scaling and a slow magnetic field decrease, the usual Fermi processes
are unable to generate ultra high energy cosmic rays (UHECRs) in GRBs. We
propose to develop another scenario of relativistic Fermi acceleration in the
internal shock stage. We present the results of a realistic Monte-Carlo
simulation of a multi-front acceleration which clearly shows the possible
generation of UHECR. The amount of energy converted into UHECRs turns out to be
a sizeable fraction of the magnetic energy.Comment: 22 pages, accepted for publication in A&
Synchrotron Emissions in GRB Prompt Phase Using a Semi Leptonic and Hadronic Model
In this communication devoted to the prompt emission of GRBs, we claim that
some important parameters associated to the magnetic field, such as its index
profile, the index of its turbulence spectrum and its level of irregularities,
will be measurable with GLAST. In particular the law relating the peak energy
Epeak with the total energy E (like Amati's law) constrains the turbulence
spectrum index and, among all existing theories of MHD turbulence, is
compatible with the Kolmogorov scaling only. Thus, these data will allow a much
better determination of the performances of GRBs as particle accelerators. This
opens the possibility to characterize both electron and proton acceleration
more seriously. We discuss the possible generation of UHECRs and of its
signature through GeV-TeV synchrotron emission.Comment: 30th International Cosmic Ray Conference (ICRC2007) - Proceeding
#107
On the Signature of Highest Energy Particles in Gamma-Ray Bursts
The launch of Fermi observatory opens new possibilities to develop diagnosis of Gamma-Ray Burst parameters, especially during their prompt emission. In this paper, first, we focus on the issue of the observability of the electron distribution cutoff , which is very sensitive to magnetic field parameters (intensity, turbulence level...). Its observability mainly depends on the importance of the Self-Synchro-Compton emission and, of γ-γ absorption process, that we calculate by taking account of the important stratification of the medium. Actually we found wide possibilities to observe or deduce the electron distribution cutoff and thus constrain magnetic parameters in the outflow of the burst. Then, we also focus on the possible gamma signature of the cosmic ray production during the prompt emission, through their synchrotron emission around a few GeV. Again we look at the γ-γ absorption process and found nevertheless favorable conditions (particularly if B ∝ 1/r) to observe this signature for some range of magnetic parameters, when the Compton parameter is sufficiently small (Y < 10 −2)
Gamma-Ray Bursts and Cosmic Rays
Les sursauts gamma sont parmi les phénomènes les plus énergétiques présents dans l'Univers. Leurs principales propriétés observationnelles et théoriques sont tout d'abord rappelées. Elles permettent d'envisager l'accélération de particules, ou rayons cosmiques, suivant des mécanismes de Fermi, via un choc externe ultra-relativiste mais également via des chocs internes. Le régime diffusif de Bohm, habituellement utilisé pour décrire l'accélération des rayons cosmiques dans les chocs internes, s'avère inapproprié et reste incompatible avec les observations et le modèle standard associé. Une autre hypothèse, plus aboutie sur le plan théorique, est considérée ici: celle d'un régime diffusif associé à une turbulence de type Kolmogorov. Ce dernier conduit, malheureusement, à un processus d'accélération bien moins efficace, qui reste incapable de produire des rayons cosmiques ultra-énergétiques ( eV). Les conséquences d'un tel processus sur l'émission à haute énergie sont détaillées et permettent, notamment, de rendre compte du spectre des émissions promptes observées. Le problème de la génération des rayons cosmiques ultra-énergétiques au sein des sursauts gamma est résolu d'une autre façon: un mécanisme d'accélération additionnelle, sur les irrégularités magnétiques présentes lors de la phase des chocs internes, est proposé. Celui-ci, assimilable à un processus de Fermi relativiste, est étudié analytiquement et numériquement. Les résultats numériques confirment l'efficacité du scénario envisagé et montrent que les capacités accélératrices des sursauts gamma sont tout à fait suffisantes pour produire une quantité importante de rayons cosmiques ultra-énergétiques. Enfin, une signature de ces rayons cosmiques est mise en évidence: il s'agit d'une émission synchrotron d'origine hadronique autour du GeV qui pourrait être observée.Gamma-Ray Bursts are known as one of the most energetic phenomena in the Universe. First, observational and theoretical properties of Gamma-Ray Bursts are recalled. They constitute a strong support in studying cosmic ray acceleration in the external shock but also, in the internal shocks. The Fermi acceleration, in the internal shock model, is usually considered with an assumption of a Bohm scaling: the Bohm's conjecture, which is not confirmed by theory or by numerical simulation, leads to unrealistic conclusions in contradiction with observations and the related standard model. Another hypothesis is so studied with a Kolmogorov scaling: although the acceleration process is unable to generate Ultra-High Energy Cosmic Rays (UHECRs), the consequences on high energy emission are detailled and could explain the origine of the prompt emission. The problem of UHECR generation is solved according to an additional relativistic Fermi process operating in the internal shock phase and using MHD disturbances. A numerical simulation confirms the efficiency of a such process: the Gamma-Ray Bursts can produce an important UHECR flux. At last, synchrotron emission from UHECRs could be at the origine of an observable signature around the GeV energy range
High Energy Emission and Cosmic Rays from Gamma-Ray Bursts
The paper is devoted to the analysis of particle acceleration in Gamma-Ray
Bursts and its radiative consequences. Therefore we get on one hand constraints
on the physics and on the other hand possible signatures of particle
acceleration that could be recorded by the new gamma ray instruments. We have
previously shown that UHECRs can be generated in GRBs even with conservative
assumptions on the magnetic field and the scattering capability of its
perturbations, provided that a suitable relativistic Fermi process is at work
during the so-called "internal shock" phase. We extend here the analysis of the
consequences of these assumptions to the whole prompt emission of both
electrons and protons. Indeed, assuming that the magnetic field decays in
and that the scattering time of particles is longer than the Bohm's
assumption, in particular with a rule derived from Kolmogorov scaling, we show
with no other parameter adaptation that the intensity of the subequipartition
magnetic field, that: i) UHECRs can be generated with a sufficient flux within
the GZK-sphere to account for the CR-spectrum at the ankle. ii) The peak energy
of the gamma spectrum around 100 keV, namely the so-called , is
conveniently explained. iii) A thermal component below the is often
unavoidable. iv) The cosmic rays could radiate gamma rays around 67 MeV (in the
co-moving frame, which implies GeV for the observer) due to
-decay and a low energy neutrino emission (around 0.2 GeV) associated to
neutron decay and also neutrinos of energy between 5 and 150 GeV from muon
decay. v) The UHECRs radiate high energy gamma rays between a few tens of MeV
and 10 GeV (taking the pair creation process into account) due to their
synchrotron emission with a sufficient flux to be observable.Comment: 18 pages, 3 figures, submitted to Astrophysical Journa
Persisting digital society territorial divides
The ‘Europe 2020 Strategy’ was issued in 2010 by the European Commission. This document constitutes a growth scheme for the decade 2010-2020 that aims to help the European Union to emerge from the current crisis through the so-called smart, sustainable and inclusive dimensions of growth. In this context, the basic aim of the SIESTA (“Spatial Indicators for a ‘Europe 2020 Strategy’ Territorial Analysis”) Project has been to illustrate the territorial dimension of the ‘Europe 2020 Strategy’. In other words, to show how this document acts territorially, particularly at the regional scale, but, when possible, also at the urban level. The SIESTA Project has been funded by ESPON (“European Observation Network for Territorial Development and Cohesion”), a European Commission Programme whose mission is to support policy development in relation to the aim of territorial cohesion and a harmonious development of the European territory. This book includes most of the main findings and conclusions obtained through research of the SIESTA Project. The contents were presented and discussed as keynote addresses or communications at the SIESTA Final Conference held in Santiago de Compostela, Galicia, on 4-5 April 2013
Η βιωμένη πραγματικότητα του μετώπου: Οι Βαλκανικοί πόλεμοι (1912-1913) μέσα από επιστολές και ημερολόγια Ελλήνων στρατιωτών
Το παρόν πόνημα μελετά τους Βαλκανικούς Πολέμους του 1912-1913 μέσα από τα βιώματα που καταγράφονται στις επιστολές και τα προσωπικά ημερολόγια Ελλήνων στρατιωτών. Αρχικά, μελετάται η χρησιμότητα των επιστολών και των ημερολογίων ως πρωτογενείς πηγές στο ιστορικό αφήγημα. Έπειτα, παρουσιάζεται το ιστορικό υπόβαθρο, το πλαίσιο αναφοράς της περιόδου εκείνης και η διεξαγωγή των Βαλκανικών Πολέμων. Στο δεύτερο μισό, η έρευνα προχωρά στη μελέτη των πηγών. Πρώτα παρουσιάζεται το περιεχόμενό τους και στη συνέχεια, με την εφαρμογή της Κριτικής Ανάλυσης Λόγου του Norman Fairclough, αναλύονται έτσι ώστε να προκύψουν χρήσιμα συμπεράσματα και από τη χρήση του λόγου στις επιστολές και τα ημερολόγια από το μέτωπο.This postgraduate diploma thesis studies the Balkan Wars of 1912-1913 through the recorded experiences in letters and personal journals by Greek soldiers. In the beginning, the usefulness of the letters and journals as primary sources in the historical narrative is examined. Afterwards, the historical background, the reference context of the era and the Balkan Wars are presented. In the second half, the thesis proceeds to study the primary sources. First, their content is presented and then, with the application of Critical Discourse Analysis by Norman Fairclough, are analyzed, so that useful conclusions can be extracted from the use of discourse in letters and personal journals from the warfront as well
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