Multi-messenger constraints to the local emission of cosmic-ray electrons

The data on the inclusive flux of cosmic positrons and electrons ($e^++e^{-}$) have been recently collected from GeV to tens of TeV energies by several experiments with unprecedented precision. In addition, the Fermi-LAT Collaboration has provided a new energy spectrum for the upper bounds on the $e^++e^{-}$ dipole anisotropy. This observable can bring information on the emission from local Galactic sources, notably measured with high precision at radio frequencies. We develop a framework in which $e^-$ and $e^+$ measured at Earth from GeV up to tens of TeV energies have a composite origin. A dedicated analysis is deserved to Vela YZ and Cygnus Loop Supernova Remnants (SNRs), for which we consider two different models for the injection of $e^-$. We investigate the consistency of these models using the three physical observables: the radio flux from Vela YZ and Cygnus Loop at all the available frequencies, the $e^++e^-$ flux from five experiments from the GeV to tens of TeV energy, the $e^++e^-$ dipole anisotropy upper limits from 50 GeV to about 1 TeV. We find that the radio flux for these nearby SNRs strongly constraints the properties of the injection electron spectrum, partially compatible with the looser constraints derived from the $e^+ + e^-$ flux data. We also perform a multi-wavelength multi-messenger analysis by fitting simultaneously the radio flux on Vela YZ and Cygnus Loop and the $e^+ + e^-$ flux, and checking the outputs against the $e^+ + e^-$ dipole anisotropy data. Remarkably, we find a model which is compatible with all the $e^++e^-$ flux data, the radio data for Vela YZ and Cygnus Loop, and with the anisotropy upper bounds. We show the severe constraints imposed by the most recent data on the $e^+ + e^-$ dipole anisotropy.Comment: 20 pages, 9 figures. Accepted for publication in the JCAP. Changes in v3: discussion and results extended to include an evolutionary model for the injection of cosmic-ray electrons in SNR

Constraining Galactic dark matter with gamma-ray pixel counts statistics

Gamma-ray searches for new physics such as dark matter are often driven by investigating the composition of the extragalactic gamma-ray background (EGB). Classic approaches to EGB decomposition manifest in resolving individual point sources and dissecting the intensity spectrum of the remaining unresolved component. Furthermore, statistical methods have recently been proven to outperform the sensitivity of classic source detection algorithms in finding point-source populations in the unresolved flux regime. In this article, we employ the 1-point photon count statistics of eight years of Fermi-LAT data to resolve the population of extragalactic point sources and to decompose the diffuse isotropic background contribution for Galactic latitudes |b|>30 deg. We use three adjacent energy bins between 1 and 10 GeV. For the first time, we extend the analysis to incorporate a potential contribution from annihilating dark matter smoothly distributed in the Galaxy. We investigate the sensitivity reach of 1-point statistics for constraining the thermally-averaged self-annihilation cross section of dark matter, using different template models for the Galactic foreground emission. Given the official Fermi-LAT interstellar emission model, we set upper bounds on the DM self-annihilation cross section that are comparable with the constraints obtained by other indirect detection methods, in particular by the stacking analysis of several dwarf spheroidal galaxies.Comment: 11 pages, 7 figures, 1 table; v2: major changes improving the selection of the RO

PACMAS: A Personalized, Adaptive, and Cooperative MultiAgent System Architecture

In this paper, a generic architecture, designed to support the implementation of applications aimed at managing information among different and heterogeneous sources, is presented. Information is filtered and organized according to personal interests explicitly stated by the user. User pro- files are improved and refined throughout time by suitable adaptation techniques. The overall architecture has been called PACMAS, being a support for implementing Personalized, Adaptive, and Cooperative MultiAgent Systems. PACMAS agents are autonomous and flexible, and can be made personal, adaptive and cooperative, depending on the given application. The peculiarities of the architecture are highlighted by illustrating three relevant case studies focused on giving a support to undergraduate and graduate students, on predicting protein secondary structure, and on classifying newspaper articles, respectively

Struttura delle comunità zoobentoniche del Rio Bunnari (Sardegna settentrionale)

Temporal and spatial variation of macrozoobenthic communities along the Rio Bunnari was studied. Three areas were sampled according to E.B.I. index method in autumn and spring. In the high and down stream a notable number of taxa was present, whereas in the medium zone, down of the artificial lake, most stenoecious taxa desappeared. This fact could be related to the high eutrophication level of the lake that represents a local limited environmental disturbance. Down stream of this zone the presence of a rich macrozoobenthic community showed its notable potentialities of homeostasis evidenced also by the biotic index

Macrozoobenthos del Fiume Silis (Sardegna settentrionale)

This research deals with the composition and structure of macrozoobenthic community of River Silis, Northern Sardinia. Samplings, carried out in different periods of the year, allowed to display the seasonal evolution of communities. Results showed a scarce diversification of taxa but a well structured community. The recolonization, after summer drought, was also observed. At the starting of this process the most resistent organisms were present, and increasing the flow, new taxa appeared raising notable values of density. Data, utilized to determine the water quality by means of E.B.I. method, show that class of River Silis varies from II-I in the upperstream to III-II in the downstream. These results point-out a situation of environmental disturbance due to urban wastes and summer drought

Un <i>Letrado</i> sassarese al servizio della monarchia ispanica. Appunti per una biografia di Francisco Ángel Vico y Artea

Sul declinare della sua esistenza il regente sardo del Supremo Consiglio d’Aragona Francisco Ángel Vico y Artea indirizza al re Filippo IV una súplica nella quale ricapitola i momenti salienti della sua biografia di fedele servitore della Monarchia. La carriera di letrado era cominciata nel 1606 a Sassari, sua città natale, come giudice della Real Governación del Cabo di Logudoro; dopo tre anni era stato promosso a giudice della sala criminal della Real Audiencia di Sardegna ed aveva operato in quella plaza di grande prestigio e responsabilità fino al 1627, «governando aquel Reyno de Regente en todas las ocasiones de las ausencias y vacantes de los que le tenían en propiedad». Da questi primi cenni autobiografici, scritti forse nel 1645, risulta chiaro come Vico avesse assunto un ruolo politico d’assoluto rilievo già prima dell’esperienza di governo a Madrid. Nel 1626, in un momento politicamente molto delicato per il regno di Sardegna e per l’intera monarchia ispanica, surroga il regente la Cancillería del regno di Sardegna don Francisco Pacheco; copre la seconda carica del regno fino al maggio 1627, allorché lascia l’isola per occupare la plaza di regente sardo nel Consiglio d’Aragona a Madrid. La sua inarrestabile ascesa era stata costruita con grande accortezza politica. Nelle cortes del 1614 aveva sostenuto il viceré duca di Gandía, «assistiendole sin faltarle un punto - afferma nella sua súplica - siguiendo en todo sus órdenes y con su autoridad y mano se confirmó el servicio de los 125 mil escudos de los Parlamentos passados y se aumentó hasta 150 mil en beneficio del Patrimonio de Vuestra Magestad. Y en las que celebró Don Juan Vivas el año 1623 passó el suplicante los trabajos que son notorios en oposición de los que contradecían que no se formasse en aquel reyno la esquadra de Galeras y se sirviesse a Vuestra Magestad con la panática y manjativo, y con una protesta que hizo en la Junta a los que se opponían a este servicio se reducieron algunos con los quales fueron los votos superiores a los que lo contradecían y se consiguió el servicio de Vuestra Magestad con las capitulaciones que se refieren en la conclusión de las Cortes sirviendo en ambos Parlamentos de juez de greuges, tratador y habilitador»

Un caso di «economia morale» del primo Ottocento: il tumulto frumentario di Alghero del 1821

A Sardenya en els anys a cavall del ser i vuit-cents s'assisteix a un augment del nombre d&rsquo;avalots relacionats amb l'exportaci&oacute; del forment sard, i per aix&ograve; tota sedici&oacute; tenia com a fi el de boicotejar la sortida del blat cap a l&rsquo;estranger. Era una &egrave;poca aquella en la qual s'estava imposant l&rsquo;economia de mercat am la qual per&ograve; entrava en crisi el model econ&ograve;mic de l&rsquo;ancien r&eacute;gime, de tipus paternalista, que en les conviccions del poble pertocava al rei i als seus representants el deure de disciplinar les provisions de blat i de queviures per a la poblaci&oacute;. L'economia morals deis pobres no reeixia a posar-se al dia i a adequar-se als mudaments del temps, tot invocant la norma fonamental que assegurava al poble la prioritat d'acc&eacute;s al blat produ&iuml;t per ell mateix dins el territori municipal. Heus ac&iacute; explicades en s&iacute;ntesi, les raons dels tumults que, doncs, no tenien ara com a fi l&rsquo;assalt als magatzems p&uacute;blics. on es dipositava el blat per a garantir el pa als m&eacute;s pobres, sin&oacute; l&rsquo;atac als mercants privats responsables acaparadors del forment. En aquest marc s'explica tamb&eacute; el que va passar a l'Alguer al 1821 de l&rsquo;episodi del qual l'autor ofereix una documentaci&oacute; in&egrave;dita que complementa altres treballs ja apareguts dins aquesta mateixa revista sobre els tumults deis forment a l&rsquo;Alguer

"De no poderse desmembrar la corona de Aragón": Sardenya i Països Catalans, un vincle de quatre segles

-

Don Agustín de Castelví, "padre della patria" sarda o nobile-bandolero?

Sulla figura di don Agustín de Castelví, natural di Cagliari

Dal 1848 agli anni del fascismo

La storia della provincia di Sassari dalla sua nascita fino all'avvento del fascismo: la politica, la situazione di pastori e contadini, i progressisti moderati, l'età giolittiana, la grande guerra