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Tendenze demografiche recenti in Sardegna
Get PDFIn this paper a reconstruction of the recent dynamics of Sardinian
population, using official data published by ISTAT, is proposed. The period
under analysis is characterized by a declining growth rate of the population.
Moreover, the Island’s population has decreased in absolute terms between 1991
and 2001 Censuses (first preliminary data), and this happens for the first time
after three centuries of continuous growth. The point is that, though Sardinia’s
fertility transition was later compared to other regions of Italy, in the last
decades fertility has rapidly fallen towards the minimum values observed in
Italy. In this context some factors associated with the rapid change of nuptial
and reproductive behaviours are discussed
Carta della vulnerabilità intrinseca del Bacino idrografico del Rio Corr'e Pruna(Sardegna Sud-Orientale)
Get PDFThe Map of the vulnerability is a tool of remarkable importance to determine the susceptibility of an unconfined aquifer to be polluted. The method that we have adopted for its determination is the SINTACS method, elaborated by M. Civita in 1997. The select area for the study is the basin of the Rio Corr’e Pruna situated in the eastern south sector of Sardinia that is center of an intense agricultural and pastoral activity. The basin of the Rio Corr’e Pruna had already been in past object of an hydrogeological and pedological study. The results of that search have been checked and adjourned before being used for the construction of the Map. The result of the research underlines that unconfined aquifer present in the territory is to a large extent predisposed to elevated risk of pollution
Definizione lito-biostratigrafica delle unità formazionali del tardo Paleogene e Neogene del Nord Sardegna e della Corsica
Get PDFThis work proposes a terminological definition of the lithostratigraphic units in the literature and recently defined ones which make up the Tertiary successions,
especially the Miocene, outcropping in northern Sardinia. These units are then correlated with the coeval formal and informal units outcropping in Corsica. The different lithostratigraphic units are also placed within the frame of the most up-to-date zonal diagrams of planktonic Foraminifers and calcareous plankton associations currently recognized in the Mediterranean. Northern Sardinia’s Cenozoic deposits are represented by a sedimentary and volcano-sedimentary succession several hundreds of metres thick, the age of which is included within the Chattian-Aquitanian and the Pliocene. These are sediments that go from silicoclastics to mixed silicoclasticcarbonatic, sometimes richly fossiliferous, in which are inserted volcanic products going from acid to basic-intermediate and having a calc-alkaline composition almost exclusively in the Aquitanian-Burdigalian interval. They refer to three main sedimentary cycles recognized on the basis of lithostratigraphy and on the analysis of benthic macrofauna associations which will be the specific subject of a future paper. Further marine sedimentation occurs in the Early Pliocene. The first cycle evolved between the Uppermost Chattian and Late Burdigalian (N6 Zone); the second cycle began at the Uppermost Burdigalian, in correspondence to the upper part of the Globigerinoides trilobus Zone (N7 Zone) and closes in the Serravallian-Tortonian limit (G. siakensis Zone, G. siakensis - G. obliqua obliqua Subzone); finally, the third cycle in all probability begins at the Late Serravallian and ends in the Early Messinian, in correspondence to the upper part of biostratigraphic N17a Zone. On the basis of a comparative analysis of the autochthonous benthic associations, especially those with Molluscs and of the textural characteristics of the sediments, the prevalent depositional environment is that of a platform and secondly that of a slope, but in some cases fluviolacustrine and deltaic. The major sedimentary, tectonic and volcanic events which took place in north Sardinia between the Oligocene and the Pliocene, also considered in the wider context of the geodynamic evolution of the western Mediterranean area are also synthetically
described. A comparison between the geochronological, lithostratigraphic and biostratigraphic arrangement proposed here for the northern Sardinian units and that
of Corsica highlights a substantial parallelism. The main sedimentary cycles which evolved in Sardinia and Corsica between the end of the Oligocene and the Early-Middle
Miocene are found to be closely connected with the collision and post-collision phases of the northern Apennines, which in various ways and with varying intensity involved the Sardinian-Corsican block. Towards the end of the Messinian and Pliocene, the extensional tectonics of the southern Tyrrhenian is responsible, even in northern
Sardinia, for the marine ingression of the Early Pliocene located in the Baronie (Cava Fuile n. Formation) and in the Sinis regions (Nuraghe Baboe Cabitza B n. Formation),
as well as for widespread volcanic activity of a prevalently basaltic alkaline nature (the «Plio-Pleistocene volcanic cycle»). The continental deposits of the Middle-Late Pliocene of the Nuraghe Casteddu (Orosei) Formation also document an erosional phase connected with the neotectonic movements of the southern Tyrrhenian area. The units of the second northern Sardinian sedimentary cycle extend to Corsica (the Balistra - Capo Sperone – Cappili - Cala Labra - Capo Pertusato - Bonifacio basins, those of the Piana di Aleria, Aiaccio and Francardo - Saint Florent),with analogousfacies and good geochronostratigraphic and biostratigraphic correspondence
Microfitocenosi planctoniche in un ambiente astatico della Sardegna meridionale
Get PDFThe authors present an investigation of the ecology and the phytoplankton of Stani Saliu, located in the north of Cagliari (Southern Sardinia). The purpose of this study was to bring a contribute to the knowledge of the astatic ponds. This salt pond was studied from January 2000 to May 2001, and biotic and abiotic parameters [including,
depth, water temperature, pH, salinity, dissolved oxygen, chlorophyll, nutrients and organic dry matter] were taken into consideration. The nutrients concentration and the
primary production was quite different in the two periods of study. Twenty different genera of phytoplankton were found; a low diversity in phytoplanktonic species, and the
diversity of trends of the concentrations of principal nutrients and primary production during the two periods showed as this ecosystem was an highly unstable environment,
with slow relisience
Capitale pubblico e produttività nelle regioni italiane
Get PDFThis paper aims at contributing to the growing literature on the influence of public capital to the overall productivity levels. Using a panel of 20 Italian regions over the period 1970-1995 we estimate a production function which includes as inputs: units of labour, private capital and public capital. As a measure of public capital we compute the stock of public infrastructure at the regional level. A preliminary analysis shows that our series are cointegrated and this result ruled out the possibility of spurious regression in the estimation of the production function. Our results show that the estimated elasticity of output with respect to public capital is positive and statistically significant for the whole country and also for all the macro regions, with the exception of the Centre. Moreover, the disaggregation of public capital into functional categories emphasises the important role played by the infrastructures directly related to the economic production like transportation networks, telecommunications, airports
La mortalità infantile tra Ottocento e Novecento. La Sardegna nel panorama italiano
Get PDFIn this paper some factors affecting the spatial and diachronic
variability of the infant mortality in Italy are discussed together with the age
structure and the seasonal pattern of infant deaths in Sardinia. The first official
statistics after unification of Italy, in the nineteenth century, revealed the
existence of significant regional differences in the levels of infant and child
mortality. Sardinia seems to have been in better conditions since his infant
mortality rate appears to be lower compared to all the other Italian regions. This
advantage depends crucially on the very low risk for new-borns to die in the
first month. However, after that period, between 1 and 12 months, the mortality
rate in Sardinia was higher than the one referred to Italy average. A similar
pattern of low neonatal and high post-neonatal mortality was observed in some
areas of Great Britain (west Cornwall and south-Wales) as well, but it remains
difficult to explain
Autoecologia e ambiente dei molluschi marini alloctoni raccolti in spiagge delle coste meridionale e sud-orientale della Sardegna
Get PDFThe present work is devoted to thanatocoenosis of beached molluscs along the south and southeaster coasts of Sardinia. In sampling the 32 biosites a homogeneous «timed» method was adopted to allow a significant statistical comparison between the different associations. Overall, 188 species of molluscs were identified. Among these were found 74 bivalves, 111 gastropods, 2 scafopods and 1 polyplacophores. These species, together with their essential synonyms, were systematically classified. The
autoecological analysis of the species supplied useful information on: texture, way of life, trophic level, biocoenotic significance and bathymetric category. In particular, the structure of the associations of organisms gathered was defined and the entity of the different biocoenotic stocks represented in them was estimated. By means of the statistical analysis the possible site of the ‘bathymetric maximum’ (some 30 metres) connected with the mobilization of sediments and the remains of the molluscs contained in them was deduced, as was the biocoenosis most involved: AP, SFBC, HP). Information
on the way of life, the biocoenotic significance and texture of every single species led to the drawing up of a good approximation of the physiography of the sea bottoms in
front of the beaches that were sampled
Privatisations as price reforms: evaluating consumers' welfare changes in the UK
Get PDFThis paper analyses the effects on consumers’ welfare of the privatisation policy carried out in the UK since 1979. The approach we follow sees the privatisation of a State owned enterprise within the broader framework of the “policy reform” theory (Drèze and Stern, 1990). By adopting this perspective, the change in consumers’ welfare “with” and “without” privatisations can be studied by appropriate welfare measures. We claim that an advantage of our approach is that of being able to provide the required welfare assessment in a simplified way by means of a limited set of information. In particular, we show that a series of welfare measures only based on aggregate information can be used once one becomes ready to accept the use of first and second order approximations and a few “reasonable” assumptions on the shape of demand functions. These welfare measures are subsequently used for the evaluation of the welfare effects related to price variations in seven British privatised public utilities. We conclude that the contribution to consumers’ welfare of the privatisation policy in the UK, when compared to the huge transfers involved in the process, has been rather modest
Studio idrogeologico delle acque minerali dell'area di Zinnigas(Siliqua, Sardegna SW)
Get PDFIn the area of Zinnigas (near Siliqua, Sardegna SW) a limited extension drainage basin is present with numerous springs. The area is center of activity for catchment and bottling of the mineral waters. We think that the dimension of the ground water basin is greater than hydrologic basin. The aim of the study is to improve the knowledges on the basin and particularly:to settle the formalities of circulation of the underground waters; to reconstruct the acquifer geometry;to draw the main hydrologic parameters
Quantum mechanics, environmental fluctuations and Wigner function
Get PDFQuantum mechanics of classically chaotic systems show drastic changes when they are coupled to environment. A kicked harmonic oscillator is linearly coupled to a heat bath via its position. It is found that the effects of the bath is to suppress the quantum effect of ballistic motion shown by the uncoupled kicked oscillator. In the asymptotic time regime ballistic dynamics is destroyed and quantum-classical correspondence is restored. The Wigner distribution picture of the dynamics is adopted