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Studio della Flora Briofitica dei pauli della Sardegna
Get PDFGli ecosistemi umidi temporanei in Europa, con alternanza ciclica di fasi di inondazione, sono indicati come habitat prioritari nella ″Direttiva Europea del 21 Maggio 1992 sulla
conservazione degli habitat naturali, della flora e della fauna selvatica″ più comunemente conosciuta come Direttiva Habitat 92/43/CEE "[Stagni temporanei mediterranei (3170*)]″. La diversità di questi habitat è legata alla originalità e rarità delle comunità animali e vegetali che li popolano e alla loro autoecologia. Gli stagni temporanei sono habitat di acque dolci, di modesta profondità, visibili solamente in inverno e tarda primavera per lo più compresi in depressioni basaltiche, alimentati esclusivamente dalle piogge. L’alternanza di fasi umide e secche crea un ambiente con biodiversità unica per questi ecosistemi che rappresentano habitat potenzialmente
idonei per l’insediamento delle Briofite che svolgono un ruolo ecologico nella protezione del suolo dall’eccessivo disseccamento e dall’erosione. Con la presente indagine si è voluto monitorare la distribuzione spaziale e la dinamica temporale di colonizzazione delle Briofite, determinata da
particolari condizioni ecologiche, in diverse condizioni di inondazione. Le ricerche sono state effettuate su 34 stagni situati in 9 siti della Sardegna di cui 4 di importanza comunitaria (SIC). L’attività di campo è iniziata nel 2008 ed è stata portata a termine nel 2011. Nel corso della presente indagine sono stati eseguiti 2613 rilevamenti, e il censimento ammonta a 141 entità di cui 120 Bryophyta e 20 Marchantiophyta e 1 Anthocerotophyta. I siti sono stati visitati stagionalmente per tenere conto della strategia biologica delle specie e perché in questi habitat, nel suolo che emerge durante la fase di disseccamento, si è osservata una elevata diversità ed abbondanza di Briofite. I
campionamenti sono stati eseguiti su vari substrati: suolo, roccia e dove presente copertura arborea su corteccia alla base del tronco al fine di redigere un repertorio rappresentativo della flora Briofitica dei siti indagati. I campionamenti sono stati eseguiti secondo zonazioni a piccola scala(distinte in cintura esterna, intermedia ed interna) e lungo transetti lineari a partire dagli argini verso il centro del bacino (Bagella et al. 2009). Le analisi sono state tutte condotte a livello di siti (nove);
per l’analisi della ricchezza floristica sono stati utilizzati metodi di statistica univariata classica
(analisi della varianza ad una via, ANOVA) per verificare le differenze significative tra gli stagni temporanei rilevati in tutto il territorio regionale; per analizzare il variare della ricchezza delle Briofite negli stagni temporanei indagati in relazione ai fattori ambientali come l’altitudine, la geologia, la dimensione e la profondità degli stagni, la copertura vegetale. Per l'analisi delle
differenze tra gli stagni temporanei rilevati in tutto il territorio regionale in termini di composizione floristica e per verificare la relazione con altri fattori (dimensione pauli e copertura vegetale) è stata applicata l'analisi per le specie indicatrici (Dufrêne & Legendre, 1997). Per l'analisi della ricchezza floristica in relazione alla variabilità stagionale della disponibilità d'acqua sono state applicate analisi di statistica univariata (ANOVA) e l'analisi per le specie indicatrici (Dufrêne & Legendre,
1997). La componente Briofitica degli stagni temporanei indagati appare complessivamente condizionata da relativamente pochi fattori rispetto a quelli analizzati, inoltre la presenza del pascolo rilevata in otto siti su nove, anziché ridurre la copertura della Brioflora, apporta un contributo positivo alla ricchezza e diversità dei pauli. In particolare le orme lasciate dal calpestio
del bestiame favoriscono la sopravvivenza di quelle specie che all’arrivo della fase secca, trovano in queste nicchie dei microhabitat favorevolmente umidi. I siti indagati ospitano una Brioflora significativa e non dissimile da quella riscontrata da altri autori nell’ambito Mediterraneo
dell’habitat. (Casas et al., 1998; Hugonnot 2002; Grillas et al., 2004; Pericàs 2009; Aleffi et al.,2010)
Le nuove tutele contrattuali dei legittimari nella circolazione giuridica
Get PDFIn this thesis we examine the necessary succession rules whose main feature is the particularly high protection of the forced heirs’ rights. In other legal systems also exist some forms of protection of the reserved portion, but not as intense as in our legal system. One of the clearest example of the level of protection of forced heirs rights is given by the fact that if the testamentary dispositions or donations exceed the portion which the testator can legally dispose of (the reserved portion), then the forced heirs have at their disposal a specific legal action “azione di riduzione” that permits them to restore the reserved portion. The intangibility of the reserved portion and the in rem quality of the legal action aimed at restoring the reserved portion, produces important consequences on the market transaction, since it’s capable of hindering the validity of payment contracts concluded even many years before. All these aspects have lead many scholars to question this kind of legal rules pledging for a reform of them. Another question that we have analysed is the so called “family pact”, which is a contract through which an entrepreneur transfer a productive good to a family member. These kinds of transactions are excluded from the applicability of the necessary succession discipline in order to guarantee the intergeneration transfers of the enterprise. The law has actually set up a double channel in the necessary succession area: from one side, in the case of productive goods, all the potential forced heirs can sign an agreement which upsets the general rule that all forced heirs have to receive goods belonging to the testator’s asset, and they can receive instead a sum on money corresponding to the value of the goods of the asset, they should have received. When a family pact is signed both the sum of money and the goods are in principle excluded from the legal action aimed at restoring the reserved portion. As a way of conclusion we could say that frequently the different solutions adopted in commercial law have opened new paths and new interpretations, leading to law reforms, that’s why we can say that the complex system of rules of the necessary succession could be modified, taking as an example the specific solutions adopted for the “family pact”
Atomistic investigation of structure and optoelectronic properties of hybrid polymer/ZnO interfaces
Get PDFHybrid interfaces are attracting increasing interest for
photovoltaic applications due to their low cost of production compared to traditional silicon-based systems and easy processability. This is the case of polymer/metal oxide systems. In particular, hybrid P3HT/ZnO can be considered as a possible alternative to organic solar cells because, by replacing the organic electron acceptor with the inorganic metal oxide it is, in principle, possible to improve the stability as well as the durability of the system. In this thesis, by means of a combination of large scale molecular dynamics simulations and ab initio methods, we study at the atomic scale the interface between the polymer P3HT and the ZnO crystalline surface.
We investigate the structure and morphology of the polymer
at the interface at low and room temperature, we characterize in detail the polymer disorder close to the ZnO
surface and we discuss the implications of this disorder
on transport properties. Furthermore, we investigate the
possible presence of residual molecules of solvent at the interface after the synthesis process, that can affect the properties of the interface.
A novel strategy to improve the polymer/metal oxide interface is proposed and investigated. Specifically, we study the deposition and assembling of zinc phthalocyanine molecules on ZnO and we investigate the modification of the P3HT/ZnO interface, induced by the use of a ZnPc optically active molecular interlayer. The structure and morphology of the ZnO/ZnPc/P3HT system, studied by molecular dynamics
simulations, are used as starting point for DFT calculations. We discuss the electronic and optical properties of this ternary system reporting indications of an improvement in hybrid photovoltaic devices due to the hindering of the charge recombination and a better exploitation of the solar spectrum. This kind of architecture, theoretically designed by a multiscale predictive modeling in the present thesis, is an example of a novel class of systems whose performances are currently under experimental investigation
La nascita del programma nucleare iraniano. Washington e Teheran tra alleanza e reciproci sospetti 1956-1979
Get PDFThe purpose of this dissertation is to investigate and understand the role of the Shah of Iran, and his close relationships with the United States, in the development of the Iranian nuclear program before the Revolution of 1979. The period covered goes from the assignment of Mohammed Reza Pahlavi as Shah of Iran in 1946 to the 1979 when finally Iran and United States found an agreement about mutual nuclear cooperation.
The first part of this study examines the situation when Mohammed Reza Pahlavi became Shah of Iran and then during the ’50 when the role of the Shah was consolidated and the United States gradually gave greater support to the Iranian regime. The first step to develop nuclear energy is traced back to 1957, in connection with the increasing military and economic assistance to Iran from the Eisenhower’s Administration. In the same year, the two countries announced an agreement for cooperation and research in the peaceful uses of atomic energy. This first agreement came under the auspices of the Atoms for Peace program launched by Eisenhower. Two years after the agreement Mohammed Reza Pahlavi ordered the establishment of an institute at Teheran University, the Teheran Nuclear Research Center, and negotiated with the United States the supply of a five-megawatt reactor. Despite this important steps the Iran was not prepared to develop such an important technology and during the ’60 the United States provided nuclear fuel and equipment that Iran used to start its research up.
The second part of the dissertation examines the development of the program during the ’70 and the relation between Teheran and the Gerald Ford’s Administration. In March 1974, the Shah established the Atomic Energy Organization of Iran, and announced plans to get 23,000 megawatts of electricity from nuclear power stations. By the mid-1970s Iran had signed contracts with several Western Countries, including France and Germany, for the construction of nuclear plants and supply of nuclear fuel. At the same time the Ford’s administration began to suspect about the real intentions of the Shah and worked out several solutions to try to control the developments of Iran’s nuclear program. The mutual suspicions led to various deadlocks in the negotiations between the two countries. In this situation the United States tried to adopt some solutions that would have allowed control of the program like for example the “multinational reprocessing plant” or the “buy back solution”.
The third part examines the development of the program during the Carter’s administration. President Jimmy Carter, agreed to accommodate the Shah’s requests, but still only to the extent that U.S. proliferation concerns were met. Under Carter, finally, the Shah was willing to make all the concessions that proved he was not trying to build a bomb such as forgoing plans for plutonium processing plants and the President permitted U.S. companies to sell reactors to Iran in 1978. In 1979 the revolution was imminent and the nuclear program had to be abandoned
Nanoparticelle per la terapia dei tumori: preparazione, caratterizzazione e tossicità
Get PDFThe work of this doctoral thesis can be mainly divided in three parts. In the first part, the synthesis and characterization of different types of inorganic nanoparticles (NP) is described. The full protocol to prepare NP-GS, NP-Si)GS, and NP-Si)Au was found in literature. Stöber method-synthesized NP-Si were used as a platform to create NP-Si)GS, and NP-Si)Au. A novel method to conjugate antitumor drugs (s-Azl 6 and s-Azl 38) to Au-NP was also developed. Studies on Azl 6 and Azl 38 showed that they are highly hydrophobic, but when conjugated with Au-NPs, in the presence of an amphiphilic molecule (C), the complex (DNPC) passed through water. NP-Si, NP-GS, NP-Si)GS, and NP-Si)Au were characterized with electron microscopy, x-ray diffraction (EDS), and DLS. Although synthesis appeared to be easy to perform, results showed that NP-Si)Au did not form, while NP-GS and NP-Si)GS were obtained. NP-GS have a small diameter (2-3 nm on average), while for NP-Si and NP-Si)GS a diameter of 178-205,52 nm, and 164,80-178,66 nm respectively was calculated. TEM and SEM microscopy also indicated that NP-Si)Au corroded, and the gold envelope, that was supposed to coat the whole particule, was observed detached from the silica NP and in the form of small spheres. The reason why the synthesis of NP-Si)Au did not succeed, maybe relies on the particular type of Si-NP used. Further studies will deepen this aspect. The culture of three different types of human cell phenotypes is accurately described in the second part. For our experiments, we decided to cultivate human melanocytes, a human melanoma cell line, and human keratinocytes. Melanocytes appeared characterized by a dendritic-like morphology, and they showed a very slow growth rate. On the contrary, we observed that their corresponding tumor cells (melanoma) grew quickly and, although they were sold as adherent cells, floating living cells were also found in cultures. Finally, in human keratinocytes two morphotypes were observed. The first (the most diffused) had the typical “cobblestone shape” of keratinocytes, while the second appeared bigger than the first, flattened, and with a jagged contour. Finally, in the third part of this work, the toxicity of inorganic NP (i.e., NP-Si, NP-GS, and NP-Si)GS), DNPC, inorganic rhodaminated NP conjugated with heparin, and lipid NP containing paclitaxel (NC-Pacli), was tested on the cell phenotypes mentioned above. CellTiter Blue reagent was selected to quantify cell viability, and it was chosen among other dyes and assays for its non-toxicity and easiness of use. It was shown that among inorganic NP, only Si-NP have toxic effect, especially on healthy cells. NC-Pacli, on the contrary, caused the decrease of cell viability on healthy and tumor cells
Studio di un sistema di ritenuta stradale con montanti e nastri in legno
Get PDFThe impact of a vehicle on a barrier is a very complex phenomenon, many interaction exist between
the elements of the safety barrier and between the safety barrier and the ground. The research has
focused on the design of a new road safety barrier with wood posts and wood beams. Different
models have been verified, each models is modeled and tested under the impact of a vehicle, as
required by EN 1317-1 and EN 1317-2. The wood mechanical properties are function of moisture
content and temperature. For each model have been made to vary the temperature and the moisture
content, and have been made to calculate the indices required by UNI EN 1317. For simulation is
used the finite element code LS-DYNA, which is used in the world for the fast dynamic events and
for the crash tests. Research is focused on the calculation of crash severity indices called ASI and
THIV
Il confine orientale italiano tra contesto internazionale e lotta politica: 1943-1953
Get PDFThe issues addressed in this thesis present one of the central themes in the Italian historiographical debate, especially on the link between national / international level and how it has interacted with the history of the second half of the twentieth century. In this context, however, it became necessary to consider the first the events related to the eastern border of Italian before 1945, as these are closely linked to subsequent developments in a cause / effect is very important in order to understand the dynamics of the period covered by the research.
The purpose of this work is to investigate and study how this issue has been politically present in the debate of those parties which were protagonists in the first Republican era, such as the Italian Communist Party, the Christian Democrats and the Italian Social Movement, examining how have been formed their positions about the Italian eastern border question
Luoghi e identità: ricostruzione storica dello spazio agrario, sociale e politico della baronia di Monreale nella Sardegna dell’età moderna
Get PDFThis study undertakes an analytical, historical reconstruction of the rural, social and political space of Baronia di Monreale, currently part of the Medio
Campidano province of Sardinia, Italy. The expression “reconstruction of the rural, social and political space” entails an investigation into the various means by which the territory is exploited,
the formation and development of economic and political élites in the villages, the various forms of property ownership (conveyancing of land and property), the urban demographic patterns of villages as well as the various
typologies of dwellings . The investigation starts off with a historical exploration of the main events in
Sardinia in modern times, focusing on those concerning the Monreale area. The central part of the present study is devoted to an in-‐‑depth analysis of practices of the use of rural, agricultural space from the late Medieval period
up to early contemporary times. The research has focused in particular on the creation and development of the
estates of large landowners: records and maps in the Land Registry Office have been essential and fundamental research tools, thanks to which a graphic representation of the larger estates was made possible. The following section focuses on the social and political relations within and
among the several communities. It was possible to reconstruct the dense network of family relations which
linked the Monreale élite to people in the cities and in the rest of the region. In order to do this, both genealogical and the micro-‐‑historical approaches
have been employed, with the purpose of retracing the trajectories and the interconnections which enabled some of the representatives of Monreale families to occupy significant political and military roles in the national arena. The last part of the research has been devoted to the impacts and effects that human intervention had on the rural landscape. Land use, the testamentary dispositions, the conflicts between barons and communities have produced
far-‐‑reaching effects overtime, which have profoundly transformed the modern and contemporary landscape.
The main objective of the study is to provide an overview of the several aspects that have contributed to shaping the places which are the subject of this research. The outcomes will have some practical applications in such
areas as integrated planning, landscape conservation and development as well as in structured planning in sectors such as agriculture and handicrafts. Archive research was undertaken at Cagliari State Archives, Turin State
Archives, Historical Diocesan Archives in Ales and the historical archives in Guspini, San Gavino and Sardara municipalities. The private archives of the Orrù and Diana families were consulted, as was that of the ecclesiastic Lorenzo Tuveri from Sardara
Web Framework Points: an Effort Estimation Methodology for Web Application Development
Get PDFSoftware effort estimation is one of the most critical components of a successful software project: completing the project on time and within budget is the classic challenge for all project managers. However, predictions made by project managers about their project are often inexact:
software projects need, on average, 30-40% more effort than estimated. Research on software development effort and cost estimation has been abundant and diversified since the end of the Seventies. The topic is still very much alive, as shown by the numerous works existing in the
literature. During these three years of research activity, I had the opportunity to go into the knowledge and
to experiment some of the main software effort estimation methodologies existing in literature. In particular, I focused my research on Web effort estimation. As stated by many authors, the existing models for classic software applications are not well suited to measure the effort of Web applications, that unfortunately are not exempt from cost and time overruns, as traditional software
projects. Initially, I compared the effectiveness of Albrecht's classic Function Points (FP) and Reifer's
Web Objects (WO) metrics in estimating development effort for Web applications, in the context of an Italian software company. I tested these metrics on a dataset made of 24 projects provided by the software company between 2003 and 2010. I compared the estimate data with the real effort of each project completely developed, using the MRE (Magnitude of Relative Error) method. The experimental results showed a high error in estimates when using WO metric, which proved to be more effective than the FP metric in only two occurrences. In the context of this first work, it
appeared evident that effort estimation depends not only on functional size measures, but other factors had to be considered, such as model accuracy and other challenges specific to Web applications; though the former represent the input that influences most the final results. For this
reason, I revised the WO methodology, creating the RWO methodology. I applied this methodology to the same dataset of projects, comparing the results to those gathered by applying the FP and WO methods. The experimental results showed that the RWO method reached effort prediction results
that are comparable to – and in 4 cases even better than – the FP method. Motivated by the dominant use of Content Management Framework (CMF) in Web application
development and the inadequacy of the RWO method when used with the latest Web application development tools, I finally chose to focus my research on the study of a new Web effort estimation methodology for Web applications developed with a CMF. I proposed a new methodology for
effort estimation: the Web CMF Objects one. In this methodology, new key elements for analysis and planning were identified; they allow to define every important step in the development of a Web application using a CMF. Following the RWO method approach, the estimated effort of a Web project stems from the sum of all elements, each of them weighted with its own complexity. I tested
the whole methodology on 9 projects provided by three different Italian software companies,
comparing the value of the effort estimate to the actual, final effort of each project, in man-days. I
then compared the effort estimate both with values obtained from the Web CMF Objects methodology and with those obtained from the respective effort estimation methodologies of the three companies, getting excellent results: a value of Pred(0.25) equal to 100% for the Web CMF Objects methodology.
Recently, I completed the presentation and assessment of Web CMF Objects methodology, upgrading the cost model for the calculation of effort estimation. I named it again Web Framework Points methodology. I tested the updated methodology on 19 projects provided by three software
companies, getting good results: a value of Pred(0.25) equal to 79%.
The aim of my research is to contribute to reducing the estimation error in software development projects developed through Content Management Frameworks, with the purpose to
make the Web Framework Points methodology a useful tool for software companies
Process software simulation model of Lean-Kanban Approach
Get PDFSoftware process simulation is important for reducing errors, helping analysis of the risks and for improving software quality. In recent years, the Lean-Kanban approach has been widely applied in software practice including software development and maintenance. The Lean-Kanban approach minimizes the Work-In-Progress (WIP), which is the
number of items that are worked on by the team at any given time. It has been demonstrated that such approach can help to improve software maintenance and development
processes in industrial environments. The goal of the simulation model itself is to increase the understanding and to support decisions for planning such kind of projects. Considering the threats to validity of
the study, the accuracy and reliability of the simulation model could be shown and the simulation model implementation allows for deriving hypothesis on the impact of distribution on parameters such as throughput.
In this thesis, we describe our simulation studies, which show that the Lean-Kanban approach can indeed help to reduce the average time needed to complete maintenance
or development issues. This simulation model can simulate existing maintenance and development processes that does not use a WIP limit, as well as a maintenance and development processes that adopt a WIP limit. We performed some case studies using real data collected from different projects. The results confirmthat the WIP-limited process as advocated by the Lean- Kanban approach could be useful to increase the efficiency of software maintenance and development, as reported in previous industrial practices