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Traditional models of urban development are no longer adequate to describe current metropolitan transformations. These are
now at the centre of a debate concerning management and administration. In Italy, delays in resolving problems of urban and
metropolitan government, despite the legal framework provided by Law 142/90, have weighed heavily on the larger urban areas
of the country: Rome, Naples, Milan, which have not been able to tackle the issue of metropolitan government. Recent legislation,
while not providing a pre-defined institutional solution, allows separate administrative districts to collectively establish
metropolitan institutions of `variable geometry'. The Milan urban area is not one city, but a system of mutually-dependent
cities, linked to each other and the rest of the world by a transport network still requiring much investment. The vitality
of its economic structure (especially its small firms) is held back by seriously inadequate infrastructure and low external
economic efficiency. The provincial capital may boast `historic centrality' but the most interesting potential for development
is to be found on the periphery and in the administrative districts immediately surrounding it, in the recovery of derelict
industrial areas and dormitory towns established in the 1950s and 1960s, especially to the north. Recovery of derelict areas,
green areas, and better transport links within the urban area and with the outside world are the key elements in the reorganization
of `Greater Milan'. In this situation of rapid transformation the most appropriate political strategies involve negotiated
planning.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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F.M. Zerbi H. Dekker I. Guinouard R. Navarro P.K. Rasmussen 《Astronomische Nachrichten》2011,332(3):218-221
One year of operations demonstrated the high level of scientific performance of the X‐shooter spectrograph. The excellent science opened by this instrument is described in various papers within this volume. The purpose of this contribution is to briefly describe the novel technical solution adopted in the design and construction phase of X‐shooter that made it a successful instrument and the aforementioned science possible (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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K. G. Strassmeier R. Pallavicini J. B. Rice M. I. Andersen F. M. Zerbi 《Astronomische Nachrichten》2004,325(4):278-298
We lay out the scientific rationale for and present the instrumental requirements of a high‐resolution adaptiveoptics Echelle spectrograph with two full‐Stokes polarimeters for the Large Binocular Telescope (LBT) in Arizona. Magnetic processes just like those seen on the Sun and in the space environment of the Earth are now well recognized in many astrophysical areas. The application to other stars opened up a new field of research that became widely known as the solarstellar connection. Late‐type stars with convective envelopes are all affected by magnetic processes which give rise to a rich variety of phenomena on their surface and are largely responsible for the heating of their outer atmospheres. Magnetic fields are likely to play a crucial role in the accretion process of T‐Tauri stars as well as in the acceleration and collimation of jet‐like flows in young stellar objects (YSOs). Another area is the physics of active galactic nucleii (AGNs) , where the magnetic activity of the accreting black hole is now believed to be responsible for most of the behavior of these objects, including their X‐ray spectrum, their notoriously dramatic variability, and the powerful relativistic jets they produce. Another is the physics of the central engines of cosmic gamma‐ray bursts, the most powerful explosions in the universe, for which the extreme apparent energy release are explained through the collimation of the released energy by magnetic fields. Virtually all the physics of magnetic fields exploited in astrophysics is somehow linked to our understanding of the Sun's and the star's magnetic fields. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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F. M. Zerbi P. Span P. Conconi E. Molinari R. Mazzoleni R. Pallavicini K.G. Strassmeier 《Astronomische Nachrichten》2002,323(5):499-509
A way to fully exploit the large collecting area of modern 8–10m class telescopes is high resolution spectroscopy. Many astrophysical problems from planetary science to cosmology benefit from spectroscopic observations at the highest resolution currently achievable and would benefit from even higher resolutions. Indeed in the era of 8–10m class telescopes no longer the telescope collecting area but the size of the beam – which is related to the maximum size in which reflection gratings are manufactured – is what mainly limits the resolution. A resolution‐slit product Rφ ≃ 40,000 is the maximum currently provided by a beam of 20 cm illuminating the largest grating mosaics. We present a conceptual design for a spectrograph with Rφ ≃ 80,000, i.e. twice as large as that of existing instruments. Examples of the possible exploitation of such a high Rφ value, including spectropolarimetry and very high resolution (R ∼ 300,000), are discussed in detail. The new concept is illustrated through the specific case of a high resolution spectropolarimeter for the Large Binocular Telescope. 相似文献
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A. Bianco C. Bertarelli M. C. Gallazzi G. Zerbi E. Giro E. Molinari 《Astronomische Nachrichten》2005,326(5):370-374
Modern astronomical spectroscopy makes use of multi‐aperture slits placed in the focal plane of telescopes before light enters the spectrograph. Multiple object spectroscopy (MOS) allows several spectra to be obtained simultaneously with a multiplexing gain from the order of dozens of objects in 4m class telescopes to few hundreds in larger 8 m telescopes. Many of these devices make use of metal plates which are punched, milled or laser cut and can be used only for observation of a given astronomical target. A typical observing night requires from 4 to 20 MOS masks, which have to be prepared during an off‐line procedure, usually days before. Here we report an innovative technique to carry out multi object spectroscopy based on changes of properties of photochromic materials. Photochromic MOS masks consist of polymer thin films which can be made opaque or transparent in a restricted wavelength range using alternatively UV and visible light. Slit patterns can thus be easily written by means of a red diode laser on a UV preflashed plate. Writing time for a 10 × 10 arcmin plate is a few minutes and the whole procedure can be performed promptly after the acquisition of the field image and without mechanical debris as in milling or laser cutting. A computer controlled writing device suited for the AFOSC camera of the Asiago 1.8m telescope was built. The same focal plane mask can be UV erased and used more than 450 times. High contrasts have been reached by means of an appropriate passband filter in the light beam of the spectrograph. Our first successful observation run took place in January 2003. Spectra of selected stars in the crowded M67 cluster field and emission lines from the gaseous planetary nebula M97 were obtained. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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