Vico and the University

Few intellectuals of the seventeenth century produced their works from within the structure of an academic institution. Bacon, Hobbes, Descartes, Spinoza, Leibnitz-to mention the names of the epochal figures of that historical period-were deeply committed to a new way of thinking about knowledge. They even took part in its worldwide dissemination, but they shunned the politics and constraints, the antiquarianism and erudition of the universities as stifling any openness to the thought of the new. Bacon\u27s Cogitata et Visa (1620) ponders on and sharply indicts the educational methods followed within the universities. There were notable exceptions to this practice. One exception was Galileo; another was Comenius. Still another was Vico (1688-1744), who came later and who understood exactly why Bacon, for instance, would stay away from the university. Vico spent his entire life as a teacher of rhetoric and literature at the University of Naples, and he developed his major works both within, and in opposition to, the perimeter of Naples\u27s academic structure. The University of Naples, as we gather from his Autobiography(1725-28), was certainly not a comfortable place for Vico. Most Italian universities (Padua, Modena, Reggio) came into existence out of a schism from the University of Bologna, which was one of the two parent universities of Europe. Similarly, the University of Naples was founded against the University of Bologna by the Emperor Frederick II, who needed, among other things, experts in statecraft, agents for diplomatic missions, and lawyers to settle sundry disputes. The University of Naples was the first state school of Europe, and it never lost the trace of its institutional origin-the political censorship of the professors. The professors\u27 oaths of loyalty to the city removed all doubt as to who worked for whom. From a purely personal point of view, Vico had few reasons to harbor illusions about the ethics shaping the inner life of the university. He knew firsthand the power games academics play, and he even played some himself. His account of how he had been denied the prestigious Law Professorship that he had long coveted and had to settle for the lower-paying and less prestigious Chair of Eloquence occupies a prominent role in his autobiographical narrative

A Chandra archival study of the temperature and metal abundance profiles in hot Galaxy Clusters at 0.1 < z < 0.3

We present the analysis of the temperature and metallicity profiles of 12 galaxy clusters in the redshift range 0.1--0.3 selected from the Chandra archive with at least ~20,000 net ACIS counts and kT>6 keV. We divide the sample between 7 Cooling-Core (CC) and 5 Non-Cooling-Core (NCC) clusters according to their central cooling time. We find that single power-laws can describe properly both the temperature and metallicity profiles at radii larger than 0.1 r_180 in both CC and NCC systems, showing the NCC objects steeper profiles outwards. A significant deviation is only present in the inner 0.1 r_180. We perform a comparison of our sample with the De Grandi & Molendi BeppoSAX sample of local CC and NCC clusters, finding a complete agreement in the CC cluster profile and a marginally higher value (at ~1sigma) in the inner regions of the NCC clusters. The slope of the power-law describing kT(r) within 0.1 r_180 correlates strongly with the ratio between the cooling time and the age of the Universe at the cluster redshift, being the slope >0 and tau_c/tau_age<=0.6 in CC systems.Comment: 12 pages, 6 figures, Accepted for publication by the Astrophysical Journa

Weighing simulated galaxy clusters using lensing and X-ray

We aim at investigating potential biases in lensing and X-ray methods to measure the cluster mass profiles. We do so by performing realistic simulations of lensing and X-ray observations that are subsequently analyzed using observational techniques. The resulting mass estimates are compared among them and with the input models. Three clusters obtained from state-of-the-art hydrodynamical simulations, each of which has been projected along three independent lines-of-sight, are used for this analysis. We find that strong lensing models can be trusted over a limited region around the cluster core. Extrapolating the strong lensing mass models to outside the Einstein ring can lead to significant biases in the mass estimates, if the BCG is not modeled properly for example. Weak lensing mass measurements can be largely affected by substructures, depending on the method implemented to convert the shear into a mass estimate. Using non-parametric methods which combine weak and strong lensing data, the projected masses within R200 can be constrained with a precision of ~10%. De-projection of lensing masses increases the scatter around the true masses by more than a factor of two due to cluster triaxiality. X-ray mass measurements have much smaller scatter (about a factor of two smaller than the lensing masses) but they are generally biased low by 5-20%. This bias is ascribable to bulk motions in the gas of our simulated clusters. Using the lensing and the X-ray masses as proxies for the true and the hydrostatic equilibrium masses of the simulated clusters and averaging over the cluster sample we are able to measure the lack of hydrostatic equilibrium in the systems we have investigated.Comment: 27 pages, 21 figures, accepted for publication on A&A. Version with full resolution images can be found at http://pico.bo.astro.it/~massimo/Public/Papers/massComp.pd

The Planck Surveyor mission: astrophysical prospects

Although the Planck Surveyor mission is optimized to map the cosmic microwave background anisotropies, it will also provide extremely valuable information on astrophysical phenomena. We review our present understanding of Galactic and extragalactic foregrounds relevant to the mission and discuss on one side, Planck's impact on the study of their properties and, on the other side, to what extent foreground contamination may affect Planck's ability to accurately determine cosmological parameters. Planck's multifrequency surveys will be unique in their coverage of large areas of the sky (actually, of the full sky); this will extend by two or more orders of magnitude the flux density interval over which mm/sub-mm counts of extragalactic sources can be determined by instruments already available (like SCUBA) or planned for the next decade (like the LSA-MMA or the space mission FIRST), which go much deeper but over very limited areas. Planck will thus provide essential complementary information on the epoch-dependent luminosity functions. Bright radio sources will be studied over a poorly explored frequency range where spectral signatures, essential to understand the physical processes that are going on, show up. The Sunyaev-Zeldovich effect, with its extremely rich information content, will be observed in the direction of a large number of rich clusters of Galaxies. Thanks again to its all sky coverage, Planck will provide unique information on the structure and on the emission properties of the interstellar medium in the Galaxy. At the same time, the foregrounds are unlikely to substantially limit Planck's ability to measure the cosmological signals. Even measurements of polarization of the primordial Cosmic Microwave background fluctuations appear to be feasible.Comment: 20 pages, Latex (use aipproc2.sty, aipproc2.cls, epsfig.sty), 10 PostScript figures; invited review talk, Proc. of the Conference: "3 K Cosmology", Roma, Italy, 5-10 October 1998, AIP Conference Proc, in press Note: Figures 6 and 7 have been replaced by new and correct version

Set-theoretic solutions of the Yang–Baxter equation associated to weak braces

We investigate a new algebraic structure which always gives rise to a set-theoretic solution of the Yang–Baxter equation. Specifically, a weak (left) brace is a non-empty set S endowed with two binary operations + and ∘ such that both (S, +) and (S, ∘) are inverse semigroups and a∘(b+c)=(a∘b)-a+(a∘c)anda∘a-=-a+ahold, for all a, b, c∈ S, where - a and a- are the inverses of a with respect to + and ∘ , respectively. In particular, such structures include that of skew braces and form a subclass of inverse semi-braces. Any solution r associated to an arbitrary weak brace S has a behavior close to bijectivity, namely r is a completely regular element in the full transformation semigroup on S× S. In addition, we provide some methods to construct weak braces

Valuing Coastal Beaches and Closures Using Benefit Transfer: An Application to Barnstable, Massachusetts

Each year, millions of Americans visit beaches for recreation, resulting in significant social welfare benefits and economic activity. Considering the high use of coastal beaches for recreation, closures due to bacterial contamination have the potential to greatly impact coastal visitors and communities. We used readily-available information to develop two transferable models that, together, provide estimates for the value of a beach day as well as the lost value due to a beach closure. We modeled visitation for beaches in Barnstable, Massachusetts on Cape Cod through panel regressions to predict visitation by type of day, for the season, and for lost visits when a closure was posted. We used a meta-analysis of existing studies conducted throughout the United States to estimate a consumer surplus value of a beach visit of around $22 for our study area, accounting for water quality at beaches by using past closure history. We applied this value through a benefit transfer to estimate the value of a beach day, and combined it with lost town revenue from parking to estimate losses in the event of a closure. The results indicate a high value for beaches as a public resource and show significant losses to the town when beaches are closed due to an exceedance in bacterial concentrations

An X-ray and optical study of the cluster A33

We report the first detailed X-ray and optical observations of the medium-distant cluster A33 obtained with the Beppo-SAX satellite and with the UH 2.2m and Keck II telescopes at Mauna Kea. The information deduced from X-ray and optical imaging and spectroscopic data allowed us to identify the X-ray source 1SAXJ0027.2-1930 as the X-ray counterpart of the A33 cluster. The faint, F_{2-10 keV} \approx 2.4 \times 10^{-13} \ergscm2, X-ray source 1SAXJ0027.2-1930, $\sim 2$ arcmin away from the optical position of the cluster as given in the Abell catalogue, is identified with the central region of A33. Based on six cluster galaxy redshifts, we determine the redshift of A33, $z=0.2409$; this is lower than the value derived by Leir and Van Den Bergh (1977). The source X-ray luminosity, L_{2-10 keV} = 7.7 \times 10^{43} \ergs, and intracluster gas temperature, $T = 2.9$ keV, make this cluster interesting for cosmological studies of the cluster $L_X-T$ relation at intermediate redshifts. Two other X-ray sources in the A33 field are identified. An AGN at z$=$0.2274, and an M-type star, whose emission are blended to form an extended X-ray emission $\sim 4$ arcmin north of the A33 cluster. A third possibly point-like X-ray source detected $\sim 3$ arcmin north-west of A33 lies close to a spiral galaxy at z$=$0.2863 and to an elliptical galaxy at the same redshift as the cluster.Comment: 9 pages, 6 Figures, Latex (using psfig,l-aa), to appear in Astronomy and Astrophysics S. (To get better quality copies of Figs.1-3 send an email to: [email protected]). A&AS, in pres