1359 research outputs found
Sort by
Regole di validità e regole di responsabilità nel diritto privato
No full textThe Ph.D. dissertation focuses on the relationship between validity rules (rules of validity) and liability rules under private law, reconsidering it at a dogmatic level, with reference to the concepts of «valid contract» and «fair contract».
The first part of the research highlights the structural and functional characteristics of the two categories of rules mentioned above, whose difference evokes a principle of non-interference between them by virtue of a now-rooted legal tradition. Following this principle, the invalidity of the contract is not due to the violation of a behavioural rule (rule of conduct), whether it occurs in the form of the nullity or the possibility of annulment.
In the second part, what acts as a motor to the present examination is the reflection, in evolutionary terms, of the role of good faith within the contractual matters, especially during the formation of the contract. The question arises as to whether a bad faith conduct during the negotiations can invalidate the contract or can integrate a single responsibility for damages (and so a compensation).
The third part concentrates on the remedial profile, retracing the various positions taken in the legal literature and in case-law, also highlighting the cases that most often occur before the interpreter's evaluation. The breaches of the disclosure requirements are a clear examples of that.
In conclusion, the analysis shows how the solutions considered are critical but on the other hand sharable; hence the difficulty of adopting a single solution to balance conflictual interests: legal certainty and substantial justice
Optical and structural characterization of metal oxides and carbon nitride compounds for the development of organic/inorganic hybrid systems
Get PDFMetal oxides (MOs) play a key role in many areas of chemistry, physics and materials science. They are characterized by a wide variety of high technological interest compounds (e.g. TiO2, Fe3O4, Fe2O3, Y2O3, ZnO). The still increasing interest for this class of materials is mainly due to the ability to take advantage of their diversity to find new important applications in several research field. Their applicability, strengthened by the low cost, safety, ease of synthesis, ranges from (photo)catalysis to microelectronics and in vivo biological studies. Most of the MOs-based devices present outstanding performance derived from their reduced dimensions. To date, the research on nanostructured MOs is highly active in order to deeper gain knowledge about surface states and their influence on chemical and physical properties, motivating an always more multidisciplinary approach.
However, some characteristics of oxides can limit their use, e.g. high band gap with almost negligible absorption in the visible, lack of optical response (luminescence) or conduction band edge not sufficiently negative to promote proton reduction (limited photocatalytic activity). The introduction of doping elements in the MO matrix to reduce these limitations can have the drawbacks of the new defects generation at the surface and/or in the bulk. Other limitations can be overcome by creating hybrid materials, such as organic and inorganic systems. In such scenario, it is necessary a detailed study aimed to characterize the properties of organic material and the means of implementation of the hybrid system.
In the first part of the present thesis, we examine the stability of some exemplar metal oxides systems. The aim of this work is to extend the comprehension of nanostructured MOs phase transformation and to analyse the conditions for which the transformation takes place.
The second part presents a study on carbon nitride (CN) based molecular materials performed with spectroscopy and X-ray diffraction experiments. Our characterizations reveal that CN materials present high chemical and physical stability and good control of the optical properties.
Finally, we propose a structural and optical characterization of some carbon-nitride/ metal oxides hybrids. Firstly, we focus on Tb3+ doped Y2O3 system, a good candidate for nanosized phosphors, where organic passivation of the surfaces by melamine (C3H6N6) has the dual role of replacing species for hydroxides quenchers and activators of Tb by energy transfer mechanism.
Then, we conclude with TiO2/CN hybrids for photocatalysis applications, realized by chemical methods and atomic layer deposition, stressing the importance of functional and terminating groups of molecular systems
Unlocking Large-Scale Genomics
Get PDFThe dramatic progress in DNA sequencing technology over the last decade,
with the revolutionary introduction of next-generation sequencing, has brought
with it opportunities and difficulties. Indeed, the opportunity to study the
genomes of any species at an unprecedented level of detail has come accompanied
by the difficulty in scaling analysis to handle the tremendous data
generation rates of the sequencing machinery and scaling operational procedures
to handle the increasing sample sizes in ever larger sequencing studies.
This dissertation presents work that strives to address both these problems.
The first contribution, inspired by the success of data-driven industry, is the
Seal suite of tools which harnesses the scalability of the Hadoop framework
to accelerate the analysis of sequencing data and keep up with the sustained
throughput of the sequencing machines. The second contribution, addressing
the second problem, is a system is developed to automate the standard
analysis procedures at a typical sequencing center. Additional work is presented
to make the first two contributions compatible with each other, as to
provide a complete solution for a sequencing operation and to simplify their
use. Finally, the work presented here has been integrated into the production
operations at the CRS4 Sequencing Lab, helping it scale its operation while
reducing personnel requirements
Integrated in situ and ex situ approach for Gentiana lutea L. ssp. lutea conservation
No full textGentiana lutea L. subsp lutea (hereafter G. lutea) is a long-lived geophyte, which has high
medicinal value for the intensely bitter properties residing mainly in the root, being the main
vegetable bitter employed in homeopathy and for the liqueurs production. G. lutea is presented in
the Annex V of the Directive 92/43/EEC. In addition, it’s included in the List of endangered
medicinal plants in the Annex D to the Council Regulation (EC) No. 338/97 of EU, whose purpose
is the protection of plant species by control of their trade.
Due to a lack of knowledge on the current G. lutea distributional information in Sardinia,
Species Distribution Models (SDMs) could be even an important tool to limit search efforts by
selecting the areas where field surveys are to be carried out for guiding discoveries of new localities
and to evaluate the influence of extant and extinct localities. Once distribution knowledge was
updated, further activities performed on representative localities, including ex situ and in situ
studies were carried out.
Firstly, our contribution to conserve this specie in Sardinia, included ex situ aspects that
provided an alternative and complementary method for preventing immediate extinction and
support further interventions. The experimental examination of the time when germination occurs in
natural sites, the understanding of the seed behaviour in the soil and the investigation of the
germination response under laboratory conditions. In particular, the isolated and on the boundary
Sardinian population can differ genetically and morphologically from central populations because
of their smaller population size and greater physical and ecological distances from the centre of the
range, and may contain genotypes adapted to extreme environmental conditions; it is therefore
important to check the effect on seed ecophysiology germination on small and spatial isolated
populations. Previous studies have found that the germination of many mountain plants was
promoted by cycles of cold-wet stratification that released seed dormancy in transient and
permanent seed banks. In this way, dormancy played a key role in optimizing germination success
by controlling the timing of germination. Thus, this research would contributed to this species
conservation, suggesting the optimal protocol of germination and multiplication and, on the other
hand, the information of the different kinds of seed dormancy.
G. lutea is reported as being threatened not only by root harvesting practices, but also by
global climatic warming due to its distribution, which is restricted mainly to the upper sectors of the
mountains. Especially in mountain areas, climate warming is projected to shift species’ ranges to
higher elevations. Plant species have responded to global warming through a generally accelerated
phenology, enhanced growth and increased reproductive effort. Even fewer studies have addressed
such response of the populations at the boundary of species range distributions which are thought to
be particularly sensitive to climate change, hence it was evaluated the effect of anomalous
temperatures (extremely warm) during the year of 2015 on phenology and reproductive successful.
Monitoring the underlying drivers of this variation in phenological shifts will contribute to a
mechanistic understanding of the biological effects of climate change.
Finally, the criteria established by the IUCN that are widely employed as the gold standard
for information on the conservation status of species were applied at regional scale for G. lutea. The
assessment through the IUCN Criteria and Categories at global level was updated as Least Concern
(LC) and at Italian level as Near Threatened (NT). Considering the regional level, the only previous
assessment in Sardinia date to back to 1997 as Critically Endangered (CR), this work will contribute
to an implementation of knowledge and conservation management for this taxon. An updating of
local conservation status of G. lutea was thus provided by the analysis of its decline and comparing
its potential suitable habitats based on the emissions scenarios presented by the Intergovernmental
Panel on Climate Change (IPCC) for 2050 and 2070
Boundary control and observation of coupled parabolic PDEs
Get PDFReaction-diffusion equations are parabolic Partial Differential Equations (PDEs) which
often occur in practice, e.g., to model the concentration of one or more substances, distributed
in space, under the in
uence of different phenomena such as local chemical reactions,
in which the substances are transformed into each other, and diffusion, which causes
the substances to spread out over a surface in space. Certainly, reaction-diffusion PDEs
are not confined to chemical applications but they also describe dynamical processes of
non-chemical nature, with examples being found in thermodynamics, biology, geology,
physics, ecology, etc.
Problems such as parabolic Partial Differential Equations (PDEs) and many others
require the user to have a considerable background in PDEs and functional analysis before
one can study the control design methods for these systems, particularly boundary control
design.
Control and observation of coupled parabolic PDEs comes in roughly two settingsdepending
on where the actuators and sensors are located \in domain" control, where
the actuation penetrates inside the domain of the PDE system or is evenly distributed
everywhere in the domain and \boundary" control, where the actuation and sensing are
applied only through the boundary conditions.
Boundary control is generally considered to be physically more realistic because actuation
and sensing are nonintrusive but is also generally considered to be the harder problem,
because the \input operator" and the "output operator" are unbounded operators.
The method that this thesis develops for control of PDEs is the so-called backstepping
control method. Backstepping is a particular approach to stabilization of dynamic
systems and is particularly successful in the area of nonlinear control. The backstepping
method achieves Lyapunov stabilization, which is often achieved by collectively shifting
all the eigenvalues in a favorable direction in the complex plane, rather than by assigning
individual eigenvalues. As the reader will soon learn, this task can be achieved in a rather
elegant way, where the control gains are easy to compute symbolically, numerically, and
in some cases even explicitly.
In addition to presenting the methods for boundary control design, we present the dual
methods for observer design using boundary sensing. Virtually every one of our control
designs for full state stabilization has an observer counterpart. The observer gains are
easy to compute symbolically or even explicitly in some cases. They are designed in
such a way that the observer error system is exponentially stabilized. As in the case of
finite-dimensional observer-based control, a separation principle holds in the sense that a
closed-loop system remains stable after a full state stabilizing feedback is replaced by a
feedback that employs the observer state instead of the plant state
Absorption and emission processes in organometal trihalide perovskites
Get PDFAmong the various solution processed semiconductors, organometal halide perovskites represent a noteworthy class of materials thanks to their unique combination of optoelectronic properties: efficient charge transport, favorable emission properties, strong light absorption and optical gap tunability stand for the key features of these novel semiconductors and make them appealing for the realization of a new generation of low-cost solar cells and optical emitters. Recently, scientists have devoted large efforts to study perovskites as absorbers in solar cells, reaching energy conversion efficiencies even higher than 20%. However, in spite of such an intense research, fundamental aspects of the photophysics remain still elusive, generating lively debates among researchers from all over the world. One of the more interesting debates concerns the nature of the photoexcited species. Being organometal perovskites hybrid materials, theoretically it is not clear if the excited states are dominated by bound or unbound electron-hole states. Initial publications on optical properties assumed that perovskites exhibit excitonic properties, feature typical of organic materials. On the contrary, recent optical spectroscopy reports converge to state that the majority of band-edge optical excitations at room temperature are free carriers, as it happens in inorganic semiconductors. Whether photoexcitations result in bound or unbound electron-hole pairs is not a problem of minor importance, because the design of optoelectronic devices strongly depends on it. As an example, if light absorption gives rise to bound electron-hole states, a heterojunction is necessary to split charges and produce a current flow in a solar cell, while such architecture is not necessary if electron-hole states are unbound, since only an electric field is needed to separate charges. Another debate concerns the physical reasons that support the prevalence of free carriers over bound electron-hole pairs. A small value of the exciton binding energy could justify such finding, as thermal excitation at room temperature could ionize excitons. Consequently, a precise and reliable determination of the exciton binding energy results to be of primary importance. However, exciton binding energies have been reported from less than 5 meV to over 50 meV and it has even been suggested that ionic screening could decrease the exciton binding energy with temperature. At the present, a consensus concerning the exciton binding energy is lacking. In addition to the potential use in photovoltaics (PV), organometal perovskites could be employed also as active media in light emitting devices. Different works reported amplified spontaneous emission (ASE) at injected carrier densities comparable to ones typical of organic semiconductors, making perovskites promising for the realization of a new generation of lasers. However, such reports demonstrated ASE only under impulsive excitation, a regime far from the continuous operation of real lasers, where different parasitic and warming processes are involved. Hence, further investigations are needed to state if perovskites can be actually used in future laser devices. Herein, we will discuss in details experimental results obtained by optical spectroscopy measurements, providing both a deep understanding of the photophysical properties of organometal perovskites and the possible solution to the unsolved problems we mentioned before. Chapter 1 deals with a general description of perovskites and their potential applications, while both the techniques and experimental setups with which we carried out optical spectroscopy experiments are described in Chapter 2. After, we will start discussing the nature of the photoexcitations of organometal trihalide perovskites in Chapter 3, where we will show that an electron-hole plasma exists in a wide excitation range, ranging from light intensities much smaller than those typical of solar illumination to those typical to obtain light amplification. The issue concerning the determination of an accurate exciton binding energy is addressed in Chapter 4, where we will apply the Elliot’s theory of Wannier excitons to study the absorption spectra at the band-edge. Finally, Chapter 5 concerns the study of optical amplification, where optical thermometry and rate equations will be used to estimate the magnitude of the warming processes that are established under cw regim
Magnetoelectric, multiferroic, wide-gap, and polar oxides for advanced applications: first-principles theoretical studies
Get PDFThis Ph.D. thesis reports a theoretical study of electronic and structural properties of several materials relevant
for electronic and optical applications. In the last few years, in fact, the renaissance of many physical effects
has evolved rapidly, firstly due to new nano-fabrication techniques that allow us to implement advanced
materials in numerous innovative structures and devices.
The first part of this thesis is related to a new class of multi-functional magnet materials called multiferroics,
where magnetism and ferroelectricity are strongly coupled together. Because of that, these materials can be
considered as suitable candidates for several technological applications, such as storage devices. Among the
class AnBnO3n+2 of layered-perovskite oxides, I have considered the Lanthanum titanate, La2Ti2O7 (LTO), and in
order to achieve multiferroicity in this topological ferroelectric I have suggested an isovalent substitution of the
Ti cation, non magnetic, by a magnetic one, Mn, obtaining the compound La2Mn2O7 (LMO).
Operationally, I have optimized the structures involved in the paraelectric (PE) ferroelectric (FE) transition.
Then, I have determined that LMO is a multiferroic materials since ferroelectric (FE) and magnetic order
coexist in the same phase. Finally, I have demonstrated that LMO is also a magnetoelectric materials showing a
non-zero lattice-mediated magnetoelectric tensor, α. Moreover, magnetic noncollinear spin-orbit calculations
reveal that spins point along the c direction but manifests a spin canting in the bc plane generating a weak
ferromagnetism interpretable by Dzyaloshinsky-Moriya (DM) interaction.
The second part of this thesis is based on the investigation about Gallium oxide, Ga2O3, Indium oxide, In2O3,
and their solid solutions. This study is motivated by the recently attracting interest on novel materials systems
for high-power transport devices as well as for optical ultraviolet absorbers and emitters. Resorting to an
appropriated optimization of physical properties and nanostructuration of Gallium- and Indium-based
semiconductor layers of chosen composition, it is possible to tune their key properties (such as band gaps,
interface band off-sets, vibrational absorptions, as well as, potentially, the magnetic behavior) leading overall to
novel multi-functional nanomaterials, nanostructures and devices. This may enable the design of devices based
on interfaces Ga2O3/(Ga1−xInx)2O3 or In2O3/(Ga1−xInx)2O3 such as high-power field effect transistors and far-UV
photodetectors or emitters.
Operationally, I have studied the electronic and local structural properties of pure Ga2O3 and In2O3. Then,
starting from the monoclinic (β) structure of Ga2O3, I have explored alloyed oxides, (Ga1−xInx)2O3, for different
In concentrations (x). The structural energetics of In in (Ga1−xInx)2O3 causes most sites to be essentially
inaccessible to In substitution, thus limiting the maximum In content to somewhere between 12 and 25% in this
phase. In this framework, the gap, the volume and the band offset to the parent compound exhibit also
anomalies as function of In concentration. Furthermore, I have explored alloyed oxides based on the bixbyite
equilibrium structure of In2O3 in all the In concentration range. The main result is that the alloy shows a phaseseparation
in a large composition range, exhibiting a huge and temperature-independent miscibility gap. In
addition, in accord with experimental results, intermediate alloying shows an additional crystallographic phase,
in competition with the bulk Ga2O3 and In2O3 phases. Finally, I have investigated the orthorhombic (ε) phase of
Ga2O3, that results to be the second most stable structure beside β-Ga2O3. Moreover, ε-Ga2O3 exhibits a large
spontaneous polarization and a sizable diagonal piezoelectric coefficient, comparable with typical polar
semiconductors
Storicismo e realismo nel pensiero di Alasdair Macintyre
Get PDFMy aim, in this work, is to analyze Alasdair MacIntyre’s theoretical system. MacIntyre (1929-) is a
Scottisch born and American ‘adopted’ philosopher. Critics usually framed his moral position as
representative of current normative ethics of virtue inspired from Aristotle, and his political thought
as conservative, seeing as how they consider MacIntyre as neo-comunitarian thinker. But, as I have
tried to show, this is a misunderstanding of his political position.
Anyway critics omits methodological aspect of macintyrean thought. For this reason, re-writing the
history of modernity, exposed not only in After Virtue but also in others papers, this work show the
theoretical path that drove Scottish philosopher, also through comparison with the philosophy of
science, to build a new method of enquiry that is opposed to the explanatory-predictive method
pursued by the ‘academic orthodoxy’. Indeed, this methodology, according to MacIntyre, omits
history from philosophical enquiry and so brought our contemporary culture into a state of abysmal
crisis: the ‘disquieting suggestion’.
Since following efforts to provide a solution for the moral disagreement have failed, it was
necessary to pinpoint another philosophical outlook to solve moral disagreement.
In this perspective should be read processing of his historicist method that begin by
acknowledgement of narrative character of reality.
However this approach, developed by MacIntyre to give an appropriate answer to the problems of
relativism and perspectivism, has resulted criticism of inconsistency: his position would remain
entangled in a vicious circle.
MacIntyre’s answer to the Enlightenment project failure has been labeled itself as a form of
relativism by some critics, according to which, if the MacIntyre’s aim was to find a solution to the
‘disquieting suggestion’, he would have failed. He would not reply carefully to relativism and
perspectivism. He would not be able to build a convincing theory that escapes relativism and
perspectivism, ‘the protagonist of post–Enlightenment’: he would be a relativist thinker.
How can this mistake be avoided?
Answering to this challenge, in his later writings, MacIntyre does appeal to Aristotelian-Thomism’s
synthesis and improves a concept of tradition as a intellectual inquiry.
This is the deep meaning of the macintyrean tradition–constituted and tradition–constitutive method
of enquiry, whose application on every level of investigation (epistemological, ethical and social
and anthropological) allows the full intelligibility of philosophical and ethical concepts because far
away from hypostatizing those concepts it gives a rational account by inserting them in the
respective contexts of reference and treating them as part of a whole.
The MacIntyre’s effort is thereby to connect his historical inquiry with the Aristotelian-Thomism’s
metaphysics
Principi di una antropologia della persona nell'opera di Ernesto De Martino
Get PDFIt is well known that among cultural anthropologists and philosophers there is always a historical gap and a difference of interests, language and method, which often causes a rivalry between the two disciplines that ends to stiffen anthropology in a collection of descriptions without universal principles and philosophy in a reflection of noble ambitions but unable to consider the individual human cases.
The main aim of this thesis is to read the complete works of the philosopher and anthropologist Ernesto de Martino (Naples 1908 - Rome 1965) as a point of union, isolated and sui generis, between anthropology and philosophy. The goal is to obtain, from the reading of his works, a true anthropology of the person who somehow bring order to his unsystematic work, searching in it a common thread: the person, based on the overcoming of life in value , synthesis of necessity and freedom, of transcendental truths and cultural variety. Therefore our aim is not to reconstruct philologically the work and the figure of de Martino or investigate from a historical point of view on the originality of the sources present in it. De Martino is not here treated as an end but as an instrument of knowledge of the human person in its essential aspects, moral and ethical. Thus, the aim of this work is theoretical and moral, that is: with the attempt to restore unity to the work of de Martino, we consider the ultimate and overarching meaning of his anthropology, rather than those moments of dialogue between ethnology, politics and philosophy in his work certainly present; then we wonder not so much who was de Martino as a scholar (problem still treated in this work) but what kind of scientific-philosophical proposal is his and if this proposal, given its ethical and epistemological complexity, can become the foundation for an organic human study that so far neither ethnology nor philosophy can, independently of each other, to ensure
Studio dell’attività antivirale e/o anti-infiammatoria di nuove molecole di sintesi e/o di farmaci noti
No full textThis thesis collects the work I have done during the three-year of my PhD Course. During my
first year I have started a path that has allowed me to acquire different techniques to set up
and culture animal cell lines as well as to evaluate the cytotoxic and anti-picornavirus
activities of a class of novel synthetic quinoxaline (Part I). Part of the second and all the third
year was spent at the NIAID/NIH, Hamiltion MT, USA, in the laboratory of persistent viral
diseases under the supervision of dr. Bruce Chesebro investigating the effect of statins for the
control of neuroinflammation (Part II).
Part I - Antiviral activity of quinoxalines derivates as new leads against Picornavirus
Aim: New quinoxaline derivatives were synthesized and tested for cytotoxicity and antiviral
activity against human coxsackie virus B5 [CVB-5] and polio virus type-1 [Sb-1], focusing on
the mode of action of the more potent compound Ethyl 4-[(2,3-dimethoxyquinoxalin-6-
yl)methylthio]benzoate (7a). Methods:Virus multiplication in Vero76 cells were monitored
by plaque reduction assay. Time of addition assays were performed to determine the influence
of the time of treatment on the antiviral activity. Initial steps of virus infection were dissected
into adsorption and penetration steps by switching the incubation temperature from 4°C to
37°C. Results: Four compounds (7a, 7b, 8a, 8b) showed a very potent antiviral activity
(EC50s range 0.06-3.8 μM) against CVB-5. Compound 7a resulted the most active and
selective derivative (SI >1000). Time of addition assays revealed that compound 7a interfered
with the penetration/uncoating stage of the virus cycle. Conclusion: Further experiments to
confirm the mechanism of action of the compoundare ongoing.
Part II - In vitro studies on the anti-inflammatory activity of statins during
neuroinflammation
Aim: Due to the known pleiotropic activity of statins, Four different types of statins were
investigated for their effect on the production of pro-inflammatory cytokines (IL-6 and
CXCL10) in mouse and rat cortical microglia and astrocytes primary cultures. Methods:
Primary cell cultures were obtained from 2 days old mice and Sprague-Dawley rats. The
purity of the cell cultures was verified by immunofluorescence staining. The production of
pro-inflammatory cytokines was stimulated by the mitogen LPS. The amount of cytokines
produced in the absence and in the presence of statins was determined by using an
extracellular protein kit specific for the cytokines analized. An MTT assay was performed in
order to verify the viability of the cell cultures and to exclude a possible stimulation by statins
themselves. Results: No LPS/stimulation and no statin/ cytokine inhibition was obtained in
rat cells, while in mice derived cells, there was a good LPS stimulation and three out of the
four statins inhibited of the production of IL-6 by mouse microglia.
Conclusion: Statins seems to have a good anti-inflammatory activity on mouse cells,
however, further studies should be performed in order to confirm these results. In rat cells,
further studies should be performed in order to find better conditions of stimulation. In vivo
testing of the effect of Atorvastatin and Simvastatin in mice affected by scrapie are ongoing