ARGO-YBJ is an air shower detector array with a fully covered layer of resistive plate chambers. It is operated with a high duty cycle and a large field of view. It continuously monitors the northern sky at energies above 0.3 TeV. In this paper, we report a long-term monitoring of Mrk 421 over the period from 2007 November to 2010 February. This source was observed by the satellite-borne experiments Rossi X-ray Timing Explorer and Swift in the X-ray band. Mrk 421 was especially active in the first half of 2008. Many flares are observed in both X-ray and γ-ray bands simultaneously. The γ-ray flux observed by ARGO-YBJ has a clear correlation with the X-ray flux. No lag between the X-ray and γ-ray photons longer than 1 day is found. The evolution of the spectral energy distribution is investigated by measuring spectral indices at four different flux levels. Hardening of the spectra is observed in both X-ray and γ-ray bands. The γ-ray flux increases quadratically with the simultaneously measured X-ray flux. All these observational results strongly favor the synchrotron self-Compton process as the underlying radiative mechanism.

Degrowth has evolved within a decade from an activist movement into a multi-disciplinary academic paradigm. However, an overview taking stock of the peer-refereed degrowth literature is yet missing. Here, we review 91 articles that were published between 2006 and 2015. We find that the academic degrowth discourse occupies a small but expanding niche at the intersection of social and applied environmental sciences. The discourse is shaped by authors from high-income, mainly Mediterranean, countries. Until 2012, articles largely constitute conceptual essays endorsed by normative claims. More recently, degrowth has branched out into modelling, empirical assessments, and the study of concrete implementations. Authors tend to agree in that economic growth cannot be sustained ad infinitum on a resource constraint planet and that degrowth requires far reaching societal change. Whether degrowth should be considered as a collectively consented choice or an environmentally-imposed inevitability constitutes a major debate among degrowth thinkers. We argue that the academic discourse could benefit from rigid hypotheses testing through input-output modelling, material flow analysis, life-cycle assessments, or social surveys. By analyzing the potentials for non-market value creation and identifying concrete well-being benefits, the degrowth discourse could receive wider public support and contribute to a paradigmatic change in the social sciences.

We report the observation of TeV γ -rays from the Cygnus region using the ARGO-YBJ data collected from 2007 November to 2011 August. Several TeV sources are located in this region including the two bright extended MGRO J2019+37 and MGRO J2031+41. According to the Milagro data set, at 20 TeV MGRO J2019+37 is the most significant source apart from the Crab Nebula. No signal from MGRO J2019+37 is detected by the ARGO-YBJ experiment, and the derived flux upper limits at the 90% confidence level for all the events above 600 GeV with medium energy of 3 TeV are lower than the Milagro flux, implying that the source might be variable and hard to be identified as a pulsar wind nebula. The only statistically significant (6.4 standard deviations) γ -ray signal is found from MGRO J2031+41, with a flux consistent with the measurement by Milagro.

Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called Moon shadow). The Moon shadow is an important tool to determine the performance of an air shower array. Indeed, the westward displacement of the shadow center, due to the bending effect of the geomagnetic field on the propagation of cosmic rays, allows the setting of the absolute rigidity scale of the primary particles inducing the showers recorded by the detector. In addition, the shape of the shadow permits to determine the detector point spread function, while the position of the deficit at high energies allows the evaluation of its absolute pointing accuracy. In this paper we present the observation of the cosmic ray Moon shadowing effect carried out by the ARGO-YBJ experiment in the multi-TeV energy region with high statistical significance (55 standard deviations). By means of an accurate Monte Carlo simulation of the cosmic rays propagation in the Earth-Moon system, we have studied separately the effect of the geomagnetic field and of the detector point spread function on the observed shadow. The angular resolution as a function of the particle multiplicity and the pointing accuracy have been obtained. The primary energy of detected showers has been estimated by measuring the westward displacement as a function of the particle multiplicity, thus calibrating the relation between shower size and cosmic ray energy. The stability of the detector on a monthly basis has been checked by monitoring the position and the deficit of the Moon shadow. Finally, we have studied with high statistical accuracy the shadowing effect in the day/''night'' time looking for possible effect induced by the solar wind

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