1,606 research outputs found

    Books Are Forever : Early Life Conditions, Education and Lifetime Earnings in Europe

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    Books are forever: Early life conditions, education and lifetime income

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    In this paper we estimate the effect of education on lifetime earnings in Europe, by distinguishing between individuals who lived in rural or urban areas during childhood and between individuals who had access to many or few books at age ten. We instrument years of education using reforms of compulsory education in nine different countries, and find that individuals in rural areas were most affected by the reforms while individuals with many books at home mostly benefited from education. Our main result is that books at home at age ten have had long-lasting beneficial effects on the individuals who were pushed by the reforms to increase their years of education

    Explicit characterization of the identity configuration in an Abelian Sandpile Model

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    Since the work of Creutz, identifying the group identities for the Abelian Sandpile Model (ASM) on a given lattice is a puzzling issue: on rectangular portions of Z^2 complex quasi-self-similar structures arise. We study the ASM on the square lattice, in different geometries, and a variant with directed edges. Cylinders, through their extra symmetry, allow an easy determination of the identity, which is a homogeneous function. The directed variant on square geometry shows a remarkable exact structure, asymptotically self-similar.Comment: 11 pages, 8 figure

    ISOGAL-DENIS detection of red giants with weak mass loss in the Galactic Bulge

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    The ISOGAL project is a survey of the stellar populations, structure, and recent star formation history of the inner disk and bulge of the Galaxy. ISOGAL combines 15 and 7micron ISOCAM observations with DENIS IJKs data to determine the nature of a source and the interstellar extinction. In this paper we report an ISOGAL study of a small field in the inner Galactic Bulge (l=0deg, b=1.0deg, area=0.035 sq. deg) as a prototype of the larger area ISOGAL survey of the inner Galaxy. The five wavelengths of ISOGAL+DENIS, together with the relatively low and constant extinction in front of this specific field, allow reliable determination of the nature of the sources. The primary scientific result of this paper is evidence that the most numerous class of ISOGAL 15micron sources are Red Giants in the Galactic bulge and central disk, with luminosities just above or close to the RGB tip and weak mass-loss rates. They form loose sequences in the magnitude-colour diagrams [15]/Ks-[15] and [15]/[7]-[15]. Their large excesses at 15micron with respect to 2micron and 7micron is due to circumstellar dust produced by mass-loss at low rates. These ISOGAL results are the first systematic evidence and study of dust emission at this early stage (''Intermediate'' AGB), before the onset of the large mass-loss phase. It is thus well established that efficient dust formation is already associated with such low mass-loss rates during this early phase.Comment: 15 pages, 9 figures, accepted for publication in Astronomy and Astrophysics Journa

    Search for Direct CP Violation in Non-Leptonic Decays of Charged Ξ\Xi and Λ\Lambda Hyperons

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    A search for direct CP violation in the non-leptonic decays of hyperons has been performed. In comparing the product of the decay parameters, αΞαΛ\alpha_{\Xi}\alpha_{\Lambda}, in terms of an asymmetry parameter, AΞΛA_{\Xi\Lambda}, between hyperons and anti-hyperons in the charged ΞΛπ\Xi \to \Lambda \pi and Λpπ\Lambda \to p \pi decay sequence, we found no evidence of direct CP violations. The parameter AΞΛA_{\Xi\Lambda} was measured to be 0.012±0.0140.012 \pm 0.014.Comment: Submitted for publication; RevTex, 13 pages, 4 figure

    Spectral asymptotics of Euclidean quantum gravity with diff-invariant boundary conditions

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    A general method is known to exist for studying Abelian and non-Abelian gauge theories, as well as Euclidean quantum gravity, at one-loop level on manifolds with boundary. In the latter case, boundary conditions on metric perturbations h can be chosen to be completely invariant under infinitesimal diffeomorphisms, to preserve the invariance group of the theory and BRST symmetry. In the de Donder gauge, however, the resulting boundary-value problem for the Laplace type operator acting on h is known to be self-adjoint but not strongly elliptic. The latter is a technical condition ensuring that a unique smooth solution of the boundary-value problem exists, which implies, in turn, that the global heat-kernel asymptotics yielding one-loop divergences and one-loop effective action actually exists. The present paper shows that, on the Euclidean four-ball, only the scalar part of perturbative modes for quantum gravity are affected by the lack of strong ellipticity. Further evidence for lack of strong ellipticity, from an analytic point of view, is therefore obtained. Interestingly, three sectors of the scalar-perturbation problem remain elliptic, while lack of strong ellipticity is confined to the remaining fourth sector. The integral representation of the resulting zeta-function asymptotics is also obtained; this remains regular at the origin by virtue of a spectral identity here obtained for the first time.Comment: 25 pages, Revtex-4. Misprints in Eqs. (5.11), (5.14), (5.16) have been correcte

    Probing the quantum-gravity realm with slow atoms

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    For the study of Planck-scale modifications of the energy-momentum dispersion relation, which had been previously focused on the implications for ultrarelativistic (ultrafast) particles, we consider the possible role of experiments involving nonrelativistic particles, and particularly atoms. We extend a recent result establishing that measurements of "atom-recoil frequency" can provide insight that is valuable for some theoretical models. And from a broader perspective we analyze the complementarity of the nonrelativistic and the ultrarelativistic regimes in this research area.Comment: LaTex, 13 page

    PROGETTO LIFE11 ENV IT 215 RESILFORMED - RESILIENZA AL CAMBIAMENTO CLIMATICO NELLE FORESTE MEDITERRANEE

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    Le condizioni climatiche delle regioni mediterranee, caratterizzate da frequenti annate siccitose, contribuiscono all’indebolimento degli ecosistemi forestali. Come risultato le foreste riducono le loro capacità produttive e sono più soggette a fenomeni di degrado secondario. Inoltre i contesti economico-sociali possono acuire il degrado con la diffusione di uno scorretto uso della risorsa (tagli boschivi, pascolamento) e con la diffusione degli incendi boschivi. L’obiettivo generale del progetto è preservare i sistemi forestali in ambiente mediterraneo dai rischi derivanti dai cambiamenti climatici, tramite processi di naturalizzazione, aumento di biodiversità e migliorata reattività, nei processi di recupero, in seguito ad eventi destabilizzanti. Obiettivo specifico è implementare una politica forestale regionale in grado di aumentare la capacità di resilienza delle foreste siciliane, migliorandone l’efficienza ecosistemica e favorendo la salvaguardia della biodiversità. Tra le azioni principali previste dal progetto, che si concluderà alla fine del 2015, si possono citare la classificazione delle categorie forestali siciliane in funzione della sensibilità alla desertificazione, l’indagine diacronica sull’uso e copertura del suolo dei principali paesaggi forestali siciliani, la definizione di prassi selvicolturali specifiche; la realizzazione di 120 ettari di interventi dimostrativi in 6 aree della Sicilia; la realizzazione di 6 piani di indirizzo forestali attraverso processi partecipativi con le popolazioni locali. Nella fase finale del progetto è prevista l’implementazione delle linee strategiche sperimentate con ResilForMed nel Piano Forestale Regionale della Sicilia

    ISOGAL: A deep survey of the obscured inner Milky Way with ISO at 7 and 15 micron and with DENIS in the near-infrared

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    The ISOGAL project is an infrared survey of specific regions sampling the Galactic Plane selected to provide information on Galactic structure,stellar populations,stellar mass-loss and the recent star formation history of the inner disk and Bulge of the Galaxy. ISOGAL combines 7 and 15 micron ISOCAM observations - with a resolution of 6'' at worst - with DENIS IJKs data to determine the nature of the sources and theinterstellar extinction. We have observed about 16 square degrees with a sensitivity approaching 10-20mJy, detecting ~10^5 sources,mostly AGB stars,red giants and young stars. The main features of the ISOGAL survey and the observations are summarized in this paper,together with a brief discussion of data processing and quality. The primary ISOGAL products are described briefly (a full description is given in Schuller et al. 2003, astro-ph/0304309): viz. the images and theISOGAL-DENIS five-wavelength point source catalogue. The main scientific results already derived or in progress are summarized. These include astrometrically calibrated 7 and 15um images,determining structures of resolved sources; identification and properties of interstellar dark clouds; quantification of the infrared extinction law and source dereddening; analysis of red giant and (especially) AGB stellar populations in the central Bulge,determining luminosity,presence of circumstellar dust and mass--loss rate,and source classification,supplemented in some cases by ISO/CVF spectroscopy; detection of young stellar objects of diverse types,especially in the inner Bulge with information about the present and recent star formation rate; identification of foreground sources with mid-IR excess. These results are the subject of about 25 refereed papers published or in preparation.Comment: A&A in press. 19 pages,10 Ps figures; problems with figures fixe
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