12 research outputs found
Bargaining over Beauty: The Economics of Contracts in Renaissance Art Markets
We study contracting practices in the market for paintings in Renaissance Italy. Building on insights from the economic analysis of contracts and qualitative analysis of primary sources, we first show that transaction costs threatened the relationship between buyer—the patron—and seller—the painter. We empirically investigate the channels through which transaction costs influenced contracting practices using a novel data set measuring the content and structure of 90 commission documents from the later 13th to the early 16th century. We find strong evidence that patrons used formal contracts to mitigate painters’ opportunism but little evidence that artists’ age-related reputation for honest dealing had a systematic effect on contracting practices
The AGILE Mission
AGILE is an Italian Space Agency mission dedicated to observing the gamma-ray Universe. The AGILE's very innovative instrumentation for the first time combines a gamma-ray imager (sensitive in the energy range 30 MeV-50 GeV), a hard X-ray imager (sensitive in the range 18-60 keV), a calorimeter (sensitive in the range 350 keV-100 MeV), and an anticoincidence system. AGILE was successfully launched on 2007 April 23 from the Indian base of Sriharikota and was inserted in an equatorial orbit with very low particle background. Aims. AGILE provides crucial data for the study of active galactic nuclei, gamma-ray bursts, pulsars, unidentified gamma-ray sources, galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. Methods. An optimal sky angular positioning (reaching 0.1 degrees in gamma- rays and 1-2 arcmin in hard X-rays) and very large fields of view (2.5 sr and 1 sr, respectively) are obtained by the use of Silicon detectors integrated in a very compact instrument. Results. AGILE surveyed the gamma- ray sky and detected many Galactic and extragalactic sources during the first months of observations. Particular emphasis is given to multifrequency observation programs of extragalactic and galactic objects. Conclusions. AGILE is a successful high-energy gamma-ray mission that reached its nominal scientific performance. The AGILE Cycle-1 pointing program started on 2007 December 1, and is open to the international community through a Guest Observer Program
Bargaining over Beauty: The Economics of Contracts in Renaissance Art Markets
We study contracting practices in the market for paintings in Renaissance Italy. Building on insights from the economic analysis of contracts and qualitative analysis of primary sources, we first show that transaction costs threatened the relationship between buyer—the patron—and seller—the painter. We empirically investigate the channels through which transaction costs influenced contracting practices using a novel data set measuring the content and structure of 90 commission documents from the later 13th to the early 16th century. We find strong evidence that patrons used formal contracts to mitigate painters’ opportunism but little evidence that artists’ age-related reputation for honest dealing had a systematic effect on contracting practices
The Role of Transaction Costs in Douglass North’s Understanding of the Process of Change in Economic History
AGILE detection of intense gamma-ray activity from the blazar PKS 0537-441 in October 2008
We report the detection by the AGILE satellite of intense gamma-ray activity from the source 1AGL J0538-4424, associated with the low-energy-peaked BL Lac PKS 0537-441, during a target of opportunity (ToO) observation performed on 2008 October 10-17, triggered by a Fermi-LAT alert, together with REM and Swift observations. Aims. The quasi-simultaneous near-infrared, optical, UV, X-ray, and gamma-ray coverage allowed us to investigate the behaviour of the source in different energy bands and study the spectral energy distribution and a theoretical model that can describe the gamma-ray state observed in mid-October. Methods. AGILE observed the source with its two co-aligned imagers: the Gamma-Ray Imaging Detector (GRID) and the hard X-ray imager (SuperAGILE), sensitive in the 30 MeV-30 GeV and 18-60 keV ranges, respectively. During the AGILE observation, the source was monitored simultaneously in the UV and X-ray bands by the Swift satellite through 6 ToO observations carried out between 2008 October 8 and 17. Moreover, the source was observed in the near-infrared and optical bands by the REM telescope on 2008 October 7, 8, and 9. Results. During 2008 October 10-17, AGILE-GRID detected gamma-ray emission from PKS 0537-441 at a significance level of 5.3-sigma with an average flux of (42 +/- 11) x 10(-8) photons cm(-2) s(-1) for energies higher than 100 MeV. A significant increase in the gamma-ray activity was detected between the first and the second halves of the observing period. REM and Swift/XRT detected the source in near-infrared/optical and X-rays during a relatively low and intermediate activity state, respectively, with no signs of evident variability in the different observations. However, Swift/UVOT detected an increase between the first and the second parts of the observing period, smaller than in the gamma-rays. Conclusions. The average gamma-ray flux of PKS 0537-441 detected by AGILE is close to the average flux observed for this source by the EGRET and Fermi-LAT instruments, with an increase of a factor 3 throughout the observation period up to a flux level slightly lower than the highest flux observed by Fermi-LAT during the first 11 months of operation. The spectral energy distribution of PKS 0537-441 in mid-October 2008 seems to require two synchrotron self-Compton components to be modelled, to account for both the near-infrared/optical bump and the X-ray data, together with the information on the gamma-ray flux level observed by AGILE. An alternative model based on the external Compton radiation, which requires an accretion disk with a relatively high luminosity, is also proposed