1359 research outputs found
Sort by
Human Capital and Productivity Growth in the Italian reginal Economies: a sectoral analysis
Get PDFThe paper examines the relationship between human capital and productivity growth with reference to the Italian regions. Two approaches can be distinguished. One belonging to the neoclassical tradition stresses the accumulation of human capital as a determinant of growth, while the other, inspired by Nelson and Phelps, emphasizes the role of the stock in developing endogenous technology and catching up with more advanced economies. These hypotheses have been tested at an aggregate level but results might be the overall outcome of different processes across sectors due to the different catching-up potential. In particular we expect the Nelson-Phelps hypothesis to be more relevant in the industrial sector where innovation is the most important growth determinant. A model is estimated which allows to test both the neoclassical and the Nelson-Phelps hypotheses breaking down the analysis by sector. The results do not confirm our expectations. In the industrial sector the neoclassical hypothesis is clearly rejected by the data. Some evidence supporting the Schumpeterian one can be detected when the technical component of human capital is taken into account but it is not robust to changes in the model specification. In the service sector the results are inconclusive as well. A positive and significant effect of human capital accumulation has been found for the whole sector but the explanatory power of this variable decreases considerably in the marketable services branch
Knowledge flows across European regions
Get PDFThe recent resurgence of growth studies has clearly established that technological progress and knowledge accumulation are among the most important factors in determining the performance of regional and national economic systems. Nonetheless, few empirical studies have tried to analyse the flows of technology and knowledge across regional economies in Europe due to the lack of adequate indicators. In this paper we propose new evidence on the characteristics of knowledge flows across European regions based on a statistical databank, set up by CRENoS, on regional patenting and citations at the European Patent Office spanning from 1978 to 2004 and classified by ISIC sectors (3 digit). We consider 175 regions of 17 countries in Europe assigning each patent a region according to the place of residence of the inventors; then, we examine in- and out-flows of patent citations as a proxy of knowledge connections, while looking also at their sectoral differences and dynamics through time. The econometric analysis is based on a model where the transmission and exchange of knowledge across regions is mainly affected by geographical distance together with a set of spatial dummy variables. Moreover, we make several controls to check for the robustness of our results with respect to the inclusion of other characteristics of the origin and destination regions (production structure, economic conditions and technological efforts) as well as different estimation methods. The main result is that knowledge flows decrease as the geographical distance between the origin and the destination region increase. Furthermore, knowledge flows tend to be higher among contiguous regions and areas within the same country
Sedimentologia e processi deposizionali della piattaforma continentale di Cagliari dal Last Glacial Maximum all'attuale
Get PDFAn acoustic and sedimentological survey was performed on the shelf of Cagliari, Southern Sardinia, to describe morphology, modern sediments and depositional processes of the shelf from the last post glacial sea level rise.
The Gulf of Cagliari is a sub-tropical, semi-arid Mediterranean area located in the southern part of the NW striking Oligo-Miocene Sardinian Rift, over which the Pliocenic Campidano Graben is superimposed. The Quaternary continental shelf developed transversally to this tectonic trough, fed by terrigenous sediments derived from the Palaeozoic metamorphic basement and from Tertiary sedimentary and volcanic rocks. The paleo-morphology influenced the depositional processes and the modern configuration of depositional environments. The shelf is at present characterized by a structural relief in the intermediate shelf, overgrown by a bioclastic bank that shelters the inner sector and can be considered similar in function to a tropical carbonate barrier. The echographic survey, consisting of 20 lines performed transversally to the coast, integrated previous acoustic and seismic data (lines and mosaic SSS, lines SBP and Sparker) and allowed, together with sedimentary data, to identify several morphological/sedimentological features. From the shore to the shelfbreak a suite of environments was detected, each characterized by distinct sedimentation and processes.
The shoreface, weakly sloped and distally seagrass-covered, that ends in a wide depression (10x2 Km) roughly parallel to the coast. A relief in the middle shelf, overgrown by the Posidonia oceanica main bank, reaching a minimum depth of 13 meters under the sea level. A middle shelf slope (depth >30 m) where a transition is observed to bare bottoms, (light limit for the growth of Posidonia). A large sand wave belt, from depths of 35÷40 meters, with gradually decreasing heigths and increasing frequencies seaward. Flat bottoms at the depth of 55 m, for the reaching of the Storm Wave Base (SWB) and vanishing of the structures. Several reliefs, stretching roughly NE–SW at 55 m depth, interpreted as submerged paleo-shorelines. Finally, a narrow outer-shelf, externally to these structures, and the shelfbrake at a depth of 115÷125 m. Sampling sites were positioned to the aid of the echographic dataset and 201 samples were taken with a 5 dm³ grab-sampler. Compositional and grain size analysis allowed to identify 9 groups of facies related to present day depositional environments. Shoreface sediments are represented by almost completely terrigenous, coarse to medium sands in the eastern sector, and finer mixed terrigenous-bioclastic sands on the western shoreface (see figure). Two groups of lithic facies are present near distinct outcrops of limestone and andesite along the cliffed coast. The inner-shelf below the fair-weather wave base is characterized by mixed quartzose-bioclastic sandy muds with bivalves while the depression is filled by a 40m thick Holocenic sequence of organic-carbonate mud and fine sands (grey on the map). Mixed facies of relict shoreface terrigenous sediments along with a present-day biogenic component (mollusks, bryozoans, red algae, echinoids and foraminifers) are found in the Posidonia oceanica bank (-15÷35 m). Seaward, a coarser, different siliciclastic component is found between -35 and -50 meters, related to depositional processes precedent to the Last Glacial Maximum (LGM). Through the sand-wave belt a transition is observed to more bioclastic, poorly sorted gravely sands of red algae and benthic foraminifera, below the SWB. The sediment is completely bioclastic but rare breakthroughs of terrigenous material in proximity to the –55 m paleo-shores show the presence of relict sediments underneath a limited surface cover. From a depth of 75 meters fine bioclastic-quartzose sands with bivalves and foraminifers are present due to and open marine reduced sedimentation during the last phases of the post-LGM sea level rise. The interpretation of these morphological and sedimentological context was based on the present-day knowledge of Pleistocene sea-level fluctuations. High-amplitude variations controlled by 20Ky precession cycles are known to have taken place in the Glacial Pleistocene (800Ky), while smaller amplitude 40Ky obliquity cycles variations were dominant during the Lower and Middle Pleistocene. During this early time the actual inner shelf was probably mostly emerged and continental processes prevailed while the sea level oscillated around a mean value of -60m ca. (external paleo-shores). Only during the Middle-Late Pleistocene were the oscillations wide enough to submerge the inner shelf during highstands. An important feature attributable to these continental processes is the inner shelf depression, that can be interpreted as the product of paleo-river erosions, lastly reactivated during the “Würmian” lowstand (MIS 4-2). The terrigenous input was then insufficient to fill up the available space during the post-glacial sea-level rise. The middle-shelf paleo-relief (under the Posidonia bank) is interpreted as the result of the highstands most often reached during the obliquity dominant transgressive cycles of the Lower Pleistocene.
The climatic-geomorphologic context determines the present day sedimentation, that is of a temperate water, mixed terrigenous-carbonate shelf. The sedimentation is highly siliciclastic in the inner shelf from fluvial-continental feeding, and bioclastic in the rest of the shelf with a maximum productivity along the Posidonia bank and its foreslope. A second important productivity is present at greater depths (50-65m) with the rhodalgal biocenosys.
In the middle and outer shelf the relict siliciclastic component is related to previous eustatic phases and attributable to continental and nearshore deposits lying underneath the actual shelf’s buildup. Analogous depositional contexts must be attributed to the precedent highstand phases of the Middle-Upper Pleistocene. Otherwise, during glacio-eustatic phases of falling, lowstand and rising sea level, the shelf was characterized by terrigenous continental sedimentation or shoreface sequences that are currently resedimented in the middle and outer shelf. Finally, the depositional model of this shelf alternates between phases of terrigenous-carbonate sedimentation of middle latitude, with a poorly rainy, warm Mediterranean climate during highstands, and terrigenous phases during lowstands with rather rainy, cooler Mediterranean climate
La flora del distretto minerario di Montevecchio (Sardegna sud-occidentale)
Get PDFA contribution to the knowledge of the flora of the mining
district of Montevecchio is reported, focussing on the plants colonizing highly polluted substrata, produced or altered by
the mining activity.
In the present survey, 373 taxonomic units have been recorded, ranking as follows: 332 species, 36 subspecies, 3 varieties,
2 hybrids. On old racking basins and dumps, 192 taxa have been recorded: 170 species, 20 subspecies, 1 variety, 1 hybrid.
Further 181 taxa (162 species, 16 subspecies, 2 varieties, and 1 hybrid) are missing on racking basins and dumps, but grow,
however, in the nearby areas.
The surveyed taxa belong to 73 families and 252 genera, but only 53 families and 146 genera are represented on racking
basins and mining dumps. The top three families are: Asteraceae (42 taxa, 11,3% of the total), Fabaceae (36 taxa, 9.7%)
and Poaceae (28 taxa, 7.5%). The top three genera are: Trifolium and Ophrys (8 taxa), followed by Euphorbia (6 taxa).
The biological spectrum highlights the remarkable Mediterranean connotation of the investigated district, being the therophytes
42,1% of the whole flora, followed by the hemicryptophytes (22,5%).
The chorologic spectrum is dominated by the Mediterranean chorotype (56.6%), including circum-Mediterranean
(39.4%), W-Mediterranean (8.0%) and endemic taxa (7.2%). Further 22.3% of the surveyed taxa have a wider distribution
range, but centered, however, in the Mediterranean region.
As concerns the endemics, 26 taxa have been found, of which 21 species and 5 subspecies. Asteraceae and Scrophulariaceae
resulted the richest in endemic taxa (3 units each). Most of the recorded endemics have a Tyrrhenian-insular distribution;
with reference to the biogeographic units of the Mediterranean region, they belong to the Italo-Tyrrhenian superprovince
Valutazione dell'efficienza, efficacia e sicurezza di vettori lentivirali nel trasferimento del gene CFTR in sistemi modello di epitelio respiratorio in fibrosi cistica
Get PDFOne of the possible strategies for therapy of Cystic Fibrosis is based on gene therapy. Gene therapy goal is to provide a normal copy of CFTR gene to defective tissues by using different gene transfer agents. HIV-1 derived vectors allow a prolonged expression of therapeutic gene and they are able to infect quiescent cells like respiratory epithelium cells.
Primary goal of the project is concerned with the realization of a lentivirus working live agent, transferring CFTR WT gene, or SHRNA molecules directed against ENAC subunits; ENAC is a sodium channel hyperactive in cystic fibrosis
Il Caucaso, transizione politica ed economica. Una analisi transfrontaliera.
No full textSouthern Caucasus (Transcaucasia) is a dichotomous region. The states forming this area are characterized by deep dissimilarities, but at the same time they share part of their past and many of their future expectations. A common historical legacy, together with a particular people's Weltanschauung and a geographic contiguity render Georgja, Armenia and Azerbaijan a group of countries that are united in their several differences.
The aim of this PhD Thesís is the study of the political and economic transition of Armenia, Georgia and Azerbaijan. On the basis of the potitical science, social studies, economic development and the transition scientific literature, some structural indicators have been chosen in order to elaborate a macro-analysis on their present level of democratic and economic development. As for the economic section, comparative analyses of the economic and financial performances have been adopted.
The results of this studies and the analysis of the indicators have been submitted to the scrutiny of a group of scholars coming from Armenia, Georgia, Azerbaijan, Russian Federation and Europe, composing a so-called DELPHI Group. The main goal was to have an impartial and scientific opinion about the quality of the analysis. The results indicating the different level of the structural development (also summarised in a numerical coefficient) allowed giving the three countries a "democracy score", commonly used by the scientific community.
The analysis alIowed to classify Georgia and Armenia as hybrid regimes, in which the potential for sustainable, liberal democracy is unclear, corruption is widespread and presents a major impediment to political and economic development. As for Azerbaijan it was defined as a semi-consolidated authoritarian regme, in which it failed to meet even the minimum standards of electoral democracy, State presence in the economic sector and widespread corruption represent an obstacle for development.
Political and economic transition of Transcaucasian countries seems to have a checkered trend, because there are still too many systemic internal fractures characterizing in these countries and too many international components can act and/or dominate their individual choices
Studio del gene AHSP nelle β-Talassemie
Get PDFObjective: To establish whether AHSP might have a role in modifying the clinical severity of beta-thalassemia.
Background: The severity of beta-thalassemia reflects the degree of globin chain imbalance and the excess of free alpha-globin chains that precipitate and cause oxidative damage in red cell precursors, inducing their premature destruction (ineffective erythropoiesis). AHSP is an abundant erythroid-specific protein that binds specifically to free alpha-globin and prevents its precipitation in vitro. It has been demonstrated in the animal model that AHSP is required for normal haemoglobin production and that it acts as a chaperone, to prevent the harmful aggregation of alpha-globin during normal erythroid development and in diseases with globin chain imbalance.
Patients and methods: AHSP gene (~1.4 Kb) and its promoter region was directly sequenced from PCR amplified DNA on ABI PRISM 3100, in 19 thalassemia intermedia and 14 thalassemia major patients with similar genetic characteristics (beta39/beta39, 3 or 4 alpha-globin genes and I-II or II-II haplotype according to Orkin et al).
Results: No nucleotide mutation that might alter the structure and function of AHSP was identified. We found in the large majority of the cases the same haplotypes with the same frequencies described in S/E Asia (Viprakasit et al., Blood 2004). No difference has been found in the haplotype frequencies between the beta-thalassemia major and intermedia patients.
Conclusion: We did not find mutations or specific association between haplotype of AHSP and disease severity in these patients, suggesting that AHSP is not a disease modifier in Sardinian beta-thalassemia patients
New optimization models for empty container management
Get PDFThis thesis investigates the reasons why nowadays empty container repositioning represents a crucial issue for the shipping industry. Moreover, taking into account information collected through surveys and meetings with industrial experts, we provide a broad overview of current logistic practices for the management of empty containers in the context of international trade. We develop new optimization models in order to support shipping companies in dealing with empty container repositioning. We determine
optimal repositioning plans within the time limits imposed by planning operations. Some optimization models have been tested on real data problems provided by a shipping
company. These results show that it is possible to achieve significant savings in costs and times requested to determine repositioning plan
Un nuovo metodo per l'ottimizzazione globale
Get PDFA large number of algorithms introduced in the literature to find the global minimum of a real function relay on the search of local minima. The multistart and tunneling methods produce well known procedure. A crucial point of these algorithms is to establish whether to perform or not a new local search. In this work, after a brief description of well known global optimization methods, we consider a new technique to handle this matter. We choose to carry on a local search according to a probability D that is calculated so as to minimize the average number evals of function evaluations needed to get a new local minimum. The values required to calculate evals are estimated from the history of the algorithm at the running time. The algorithm has been tested with sample problems usually used by researches and the outcome is compared with recently published results
L'effetto fisico del getto d'acqua ad alta velocità sulle terre
Get PDFLa tecnologia dei getti d’acqua ad alta velocità (water jet) consente di concentrare una grande energia su una superficie estremamente ridotta. Attualmente la ricerca si rivolge allo studio di nuove possibilità di applicazione fra le quali la bonifica dei terreni contaminati. In questo lavoro viene riportato uno studio degli effetti del getto d’acqua ad alta velocità sulle terre, e in particolare, sulle sue capacità di penetrazione in diverse condizioni operative. Lo studio è stato articolato in tre parti: nella prima viene studiata l’azione su un terreno operata da un getto fisso: dall’esame degli spostamenti misurati delle particelle di terreno coinvolte dal getto, viene ricavata la velocità di penetrazione e la sua variazione in funzione del tempo durante l’avanzamento del fronte del getto all’interno del materiale. Allo scopo è stata utilizzata una tecnica di misura derivante dalle esperienza nel campo della fluidodinamica, detta PIV (Particle Image Velocimetry), accoppiata alla videoripresa ad alta velocità, che oggi trova le sue prime applicazioni nel campo della meccanica delle terre e della geotecnica. Lo studio ha mostrato la validità della tecnica per la misura delle deformazioni indotte dal getto d’acqua su una terra, e di come questa può essere utilizzata per la misura della velocità di penetrazione del getto. Nella seconda fase è stato studiato l’effetto del movimento traslatorio e rototraslatorio del getto sullo spostamento delle particelle di terreno e quindi sulla distanza di penetrazione nel tempo fino al valore massimo raggiungibile per un dato terreno, in funzione dei parametri di movimentazione della lancia. La sperimentazione in laboratorio ha dimostrato che in una sabbia avente massa volumica pari a 1,7 kN/m³, i getti generati con ugelli di diametro 1 mm e pressione 40 MPa , formano colonne di raggio variabile 23 cm e 36 cm nel suolo secco, e un valore tra 19 cm e 27 cm nel suolo saturo, in funzione della velocità di roto-traslazione della lancia. Si può concludere che per quanto riguarda il diametro della colonna trattata i risultati ottenuti in situ sono sovrapponibili a quelli ottenuti nelle analoghe prove in laboratorio. Nella terza fase è stata esplorata attraverso la modellazione numerica la possibilità di applicazione della tecnica alla bonifica dei terreni contaminati. La tecnologia water jet consente di realizzare colonne di terreno ad alta permeabilità . Il diametro di queste colonne dipende dalle caratteristiche del terreno e dai parametri operativi del sistema di generazione del getto d’acqua. L’analisi ha messo in evidenza che la barriera costituita da colonne di terreno trattato con il water jet ha la stessa efficacia di confinamento dell’inquinante di barriere realizzate con la tecnica della trincea continua e della linea di pozzi. Inoltre il costo di realizzazione di una tale barriera è inferiore a quello relativo alla linea di pozzi e circa uguale a quella della trincea continua, presentando l’ulteriore vantaggio di non dover rimuovere il materiale contaminato