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Study of land degradation and desertification dynamics in North Africa areas using remote sensing techniques
No full textIn fragile-ecosystem arid and semi-arid land, climatic variations, water scarcity and human pressure
accelerate ongoing degradation of natural resources. In order to implement sustainable
management, the ecological state of the land must be known and diachronic studies to monitor and
assess desertification processes are indispensable in this respect. The present study is developed in
the frame of WADIS-MAR (www.wadismar.eu). This is one of the five Demonstration Projects
implemented within the Regional Programme “Sustainable Water Integrated Management (SWIM)”
(www.swim-sm.eu ), funded by the European Commission and which aims to contribute to the
effective implementation and extensive dissemination of sustainable water management policies
and practices in the Southern Mediterranean Region. The WADIS-MAR Project concerns the
realization of an integrated water harvesting and artificial aquifer recharge techniques in two
watersheds in Maghreb Region: Oued Biskra in Algeria and wadi Oum Zessar in Tunisia.
The WADIS MAR Project is coordinated by the Desertification Research Center of the University
of Sassari in partnership with the University of Barcelona (Spain), Institut des Régions Arides
(Tunisia) and Agence Nationale des Ressources Hydrauliques (Algeria) and the international
organization Observatorie du Sahara et du Sahel. The project is coordinated by Prof. Giorgio
Ghiglieri. The project aims at the promotion of an integrated, sustainable water harvesting and
agriculture management in two watersheds in Tunisia and Algeria. As agriculture and animal
husbandry are the two main economic activities in these areas, demand and pressure on natural
resources increase in order to cope with increasing population’s needs. In arid and semiarid study
areas of Algeria and Tunisia, sustainable development of agriculture and resources management
require the understanding of these dynamics as it withstands monitoring of desertification
processes.
Vegetation is the first indicator of decay in the ecosystem functions as it is sensitive to any
disturbance, as well as soil characteristics and dynamics as it is edaphically related to the former.
Satellite remote sensing of land affected by sand encroachment and salinity is a useful tool for
decision support through detection and evaluation of desertification indicating features.
Land cover, land use, soil salinization and sand encroachment are examples of such indicators that
if integrated in a diachronic assessment, can provide quantitative and qualitative information on the
ecological state of the land, particularly degradation tendencies. In recent literature, detecting and
mapping features in saline and sandy environments with remotely sensed imagery has been reported
successful through the use of both multispectral and hyperspectral imagery, yet the limitations to
both image types maintain “no agreed-on best approach to this technology for monitoring and
mapping soil salinity and sand encroachment”. Problems regarding the image classification of
features in these particular areas have been reported by several researchers, either with statistical or
neural/connectionist algorithms for both fuzzy and hard classifications methods.
In this research, salt and sand features were assessed through both visual interpretation and
automated classification approaches, employing historical and present Landsat imagery (from 1984
to 2015).
The decision tree analysis was chosen because of its high flexibility of input data range and type,
the easiness of class extraction through non-parametric, multi-stage classification. It makes no a
priori assumption on class distribution, unlike traditional statistical classifiers. The visual
interpretation mapping of land cover and land use was undergone according to acknowledged
standard nomenclature and methodology, such as CORINE land cover or AFRICOVER 2000,
Global Land Cove 2000 etc. The automated one implies a decision tree (DT) classifier and an
unsupervised classification applied to the principal components (PC) extracted from Knepper ratios
composite in order to assess their validity for the change detection analysis. In the Tunisian study
area, it was possible to conduct a thorough ground truth survey resulting in a record of 400 ground
truth points containing several information layers (ground survey sheet information on various land
components, photographs, reports in various file formats) stored within the a shareable standalone
geodatabase. Spectral data were also acquired in situ using the handheld ASD FieldSpec 3 Jr. Full
Range (350 – 2500 nm) spectroradiometer and samples were taken for X-ray diffraction analysis.
The sampling sites were chosen on the basis of a geomorphological analysis, ancillary data and the
previously interpreted land cover/land use map, specifically generated for this study employing
Landsat 7 and 8 imagery. The spectral campaign has enabled the acquisition of spectral reflectance
measurements of 34 points, of which 14 points for saline surfaces (9 samples); 10 points for sand
encroachment areas (10 samples); 3 points for typical vegetation (halophyte and psammophyte) and
7 points for mixed surfaces.
Five of the eleven indices employed in the Decision Tree construction were constructed throughout
the current study, among which we propose also a salinity index (SMI) for the extraction of highly
saline areas. Their application have resulted in an accuracy of more than 80%. For the error
estimation phase, the interpreted land cover/use map (both areas) and ground truth data (Oum
Zessar area only) supported the results of the 1984 to 2014 salt – affected areas diachronic analysis
obtained through both automatic methods. Although IsoDATA classification maps applied to
Knepper ratios Principal Component Analysis has proven its good potential as an approach of fast
automated, user-independent classifier, accuracy assessment has shown that decision tree outstood
it and was proven to have a substantial advantage over the former. The employment of the Decision
Tree classifier has proven to be more flexible and adequate for the extraction of highly and
moderately saline areas and major land cover types, as it allows multi-source information and
higher user control, with an accuracy of more than 80%.
Integrating results with ancillary spatial data, we could argue driving forces, anthropic vs natural, as
well as source areas, and understand and estimate the metrics of desertification processes. In the
Biskra area (Algeria), results indicate that the expansion of irrigated farmland in the past three
decades contributes to an ongoing secondary salinization of soils, with an increase of over 75%. In
the Oum Zessar area (Tunisia), there was substantial change in several landscape components in the
last decades, related to increased anthropic pressure and settlement, agricultural policies and
national development strategies. One of the most concerning aspects is the expansion of sand
encroached areas over the last three decades of around 27%
L’Africa Occidentale Francese fra Autonomie e Fallimenti. Il caso del Soudan/Mali
Full text linkThis thesis analyses the decolonization process of West Africa French territories, since the Brazzaville’s Conference until the obtaining of Independence. The aim of this research project refers to the importance of French Soudan, nowadays Mali, in French West Africa, and how the leaders of this territory conducted the dialogue with the colonial authorities. The Soudan’s political elite followed the political direction dictated by Houphouet-Boigny, leader of the political movement which connected French territories in this area, until the decision of breaking free from this position. Modibo Keita, father of the Nation of Mali, developed new alliances between the RDA leadership, but also with other political parties and leaders, such as Senghor. Keita and the Senegalese leader tried to avoid the balkanization of West Africa, proposing a project which was based on the principles of African Unity
Optimal labor income taxation with perks
Full text linkIncentive problems arise in many economic relationships, between workers and firms as well as between those agents and the fiscal authority. If it is well known, in fact, that labor contracts tying wages to performance may mitigate the efficiency costs from unobservable effort, it is also an empirical fact that real word contracts, and the incentives provided wherein, are more frequently based on some sort of non-monetary compensation – fringe benefits, or perks, as they are called. As a result, the fiscal authority is more often called to decide on the eligibility of those perquisite goods and, therefore, on their taxability.
In spite of their diffusion, however, there is still little consensus among researchers on the reasons why perks should be provided, and what their effect on welfare might be. The standard explanation for perks usually relies on some form of agency problem. However, monitoring concerns are certainly less relevant when dealing with a fiscal authority, that, for the most part, may monitor the provision of perks better than the payment of cash.
Motivated by the concerns about how fringe benefits may restrict the revenue collection problem and affect the redistribution of resources and incentives, this research aims at investigating the relationship between the provision of perks and i) the progressivity/regressivity of the optimal transfer-tax system, and ii) the top-income marginal tax rate.
To the best of our knowledge, this thesis constitutes the first theoretical attempt to deal with the issue at hand. In fact, all existing papers that analytically study the moral hazard problem with perks, either focus on their effect on the effort responsiveness to monetary incentives, or they study the cash-perks substitutability in the optimal labor contract, absent any consideration for the insurance/incentive purposes of income taxation. To some extent, we also contribute to the literature on optimal taxation, by emphasizing the connection between the agents' responses to the fiscal system and the structure of the labor market.
Methodologically, we investigate our research agenda by following two different approaches. In Chapter 2, we develop a static version of a standard stochastic Ramsey's problem with a representative agent and an utilitarian, resource-seeking government who takes the post of the principal and owner of the only firm in the economy. When designing the optimal rules for cash payment and perk provision, the government, who is constrained by his budget balance, takes into account the agent's unobservable reactions to the tax system, and set optimal taxes so as to provide either insurance and right incentives.
In Chapter 3, however, we take an alternative perspective, and study a decentralized economy wherein an independent, self-interest firm retains full control of the provision of perks and wage payments, given the fiscal policy announced by the government. Our analysis aims at highlighting the existence of a trade-off between the opposite interests of the government and the employer, that will serve as a rationale for the characterization of the equilibrium marginal tax rate that we derive from a Nash non-cooperative interaction game between the fiscal authority and the agents in the labor market.
Our analysis suggests that, whenever perks are efficiently provided, the government trades off progressivity for perk provision. Our main conclusion, in fact, is that the (centralized) second-best efficient taxation scheme with perks is more regressive compared to its perk-less equivalent. Notably, we also find that, whenever society's preferences for public expenditure and agents' risk aversion are sufficiently low, a regressive top-income marginal tax is also consistent with a positive provision of perks. In a numerical exercise, for example, we show that a marginal tax rate of 30% allows for either i) a positive provision of perks that accounts for 1.6% of the gross income (3.2% of the agent's wage), and ii) a per-capita public expenditure which is 7% of the top-brackets taxpayers' gross income (15% of their earnings). An equilibrium allocation without perks results, instead, for a 45% marginal tax rate.
However, in spite of the ability of our theoretical framework to capture the relationship between risk aversion and efficient provision of perks, through their effect on the optimal trade-off between the insurance and incentive motives for taxation, our model has its weakness, as to regard its sensitiveness to the stochastic dominance properties of the probability distribution and the level of income in the economy. If, in the former case, deviations from the benchmark distribution are qualitatively important but quantitatively small, in the latter case, the quantitative implications of different income levels are quite important. A more precise calibration of the models and a better characterization of the results are left to future works
La pirateria marittima negli stretti di Malacca e Singapore in prospettiva storica e attuale
Full text linkMaritime piracy is still one of the most interesting manifestations of human activity by reason of the fact that it has, directly or indirectly, a number of points of contact between different problems of social, religious, political, economical and, of course, historical matter. Specifically, South-east Asia is a great example of how history, politics and religion are strongly and crucially imbued with the maritime banditry phenomenology. During the era of great maritime political entities exercising dominion along the Malay and Indonesian coasts, predation assumed character of endemicity going to fit firmly within the society, politics and economy networks. Inside Zhu Pan Zhi, the reports of the Song Dynasty about the barbarian peoples, is it possible to read about the piracy in the Great Southern Ocean (Nanyang)
«the foreign ships were often attacked by pirates. The captives were the favourite of pirates, one captive can sell for 2 liang or 3 liang gold, the piracy prevents the merchants from visiting the ports» .
Of great interest it is also the description of piracy in waters near Singapore (Temasek) and south of the straits that, in 1349, appeared in these terms:
«The Dragon-teeth Strait (longyamen) is between the two hills of Temasek barbarians, which look like dragon’s teeth’. Through the centre runs a waterway. The fields are barren and rice harvest is poor. The climate is hot with heavy rain in April and May. The inhabitants are addicted to piracy […] when junks sail to the European Ocean (Indian Ocean), the local barbarians allow them to pass unmolested, but when the junks reach the Auspicious Strait (Jilimen) on their return voyages, some 200-300 pirate prahus (boats) will put out to attack the junks for several days, the crew of junks have to fight with their arms and setting up cloth screen as a protection against arrows. Sometimes, the junks are fortunate enough to escape with a favouring wind; otherwise, the crews are butchered and the merchandise becomes pirates’ booty» .
As can be seen from the text, also the physical elements (water, poor soil, distress sea routes, monsoon climate) play an important role in explaining the aforementioned endemicity of pirate phenomenon: in one of the most relevant work by Anthony Reid, a supporter of the Braudelian method of historical investigation, it is reported that few major areas of the world have been so deeply marked by nature such as South-east Asia, going to emphasize the importance of geography in the study of human activities.
During the first part of my research, a question to which I have tried to answer was to understand the extent to which individuals, who are placed in a given geographical and historical context, act in a manner consistent with that particular geo-cultural system and how, external elements in that system, can help to change the perspective of action; in essence, I have tried to study how and to what extent India, China and Europe (Western Culture) have affected the history of the indigenous population of South-east Asia and the Straits of Malacca and Singapore in particular. The constitution of the great European colonial empires stretched from the Malacca Straits to the South China Sea, marked the beginning of a progressive modification process of maritime piracy both in terms of objectives to be achieved and also procedures to be followed; Nicholas Tarling lucidly points out in this regard “the old empires decayed, but were not replaced, and with their boundaries marauding communities appared, led by the adveturous Sharifs, or deprived aristocracies, or hungry chiefs” . The main ethnic groups who practiced piracy, the Riau-Lingga Malay, Bugis and Dayak of East Malaysia and Brunei, and Ilanun Balangingi from the southern Philippines and the Sulu sea, became corsairs in the pay of the colonial authorities and all those princes or sultans deprived of their possessions. However, alongside the politically motivated piracy, continued to resist a kind of maritime banditry conducted by fishing associations, outcasts or Chinese immigrants and so-called nomads people of the sea (Orang Laut), clanic and personalistic in nature whose cultural substrate was made up of bonds of friendship, kinship and blood.
The remarkable fact is that the two types of piracy are not mutually exclusive but, on the contrary, represented the two faces of a coin and it was not unusual for pirates and corsairs to exchange roles when political or economic contingencies were changed. Interesting in this regard it was been the reading and examination of archival documents found at the National Archives in London (The National Archives) showing exchanges of correspondence and minute of some of the leading authorities of the British Straits Settlements between the first and second half of the nineteenth century. A set of letters that, given its enormous historical and political significance I decided to bring entirely, contains the correspondence (1863-67) between the Straits Settlements Governor Orfeur Cavenagh, Abu Bakar ibn Temenggong Daing Ibrahim Temenggong of Johor and Inche Wan Ahmed, exiled prince of Pahang become rebellious and pirate. Proceeding with the analysis of the phenomenon and given the interest of the international community for the sea routes passing into the Straits of Malacca and Singapore, the next questions concerned what was the real impact of piracy on maritime trade, what costs in human and social terms it produced, which law enforcement measures riparian states and foreign countries (in colonial and post-colonial age) have come into force; in addition to these I had tried to understand who is the pirate, what are the main reasons for his actions, what is the connection, if does exist, between piracy, terrorism and organized crime. In this direction, starting from the definitions of piracy given by the International Maritime Organization and the International Maritime Bureau, I examined most of the international conventions and regional agreements in which the issue of maritime security and cooperation between states and supranational bodies is addressed, placing special attention to the rules and clauses contained in the treaties able to activate those mechanisms for cooperation and burden sharing (burden-sharing) indispensable to the solution or, more realistically, the containment of the problem. Of great relevance to this line of analysis it has proved useful the socio-anthropological approach by Carolin Liss on the links between maritime banditry, criminal syndicates and terrorist groups (criminal syndicate) and the statistical and methodological approach by Karsten von Hoesslin focused on quantity, quality and type of assaults committed at sea.
Concluded the second part of the thesis, I went to compare what is written in both historical and contemporary perspective to understand what kind of conclusion emerged from the results of my research; I asked myself, therefore, a further question: taking as a fixed point the thought of Braudel and Reid, following the method of analysis of Liss and Hoesslin, examine the archival documents and translations of ancient texts on the subject (the Sejarah Melayu and Suma Oriental of Tome Pires), given the availability (more or less declared) from South-east Asian newly established states (post-independence) to cooperation and given the interest of third actors in the straits, is it conceivable and correct to sustain now, in the first half of the new millennium, the possibility of a modification of the ancient customs and traditions and entrenched rivalry between neighboring countries on the basis of a new collective consciousness directed to a harmonious resolution, conveyed by a general law, of the phenomenon of maritime piracy? Or are we facing with a false hub of history, with a point that falsely or inappropriately is considered the turnaround from a tradition that has its roots in the coastal kingdoms of the sixth century and which is the sub-cultural layer of those population who have made the sea their source of wealth and power? To say it once again with Braudel, has the longue durée history undergone a change of route or will it repeat and renew her cycle again and again, sweetened by new technological tools and new forms of politics and economics? And if a change is in place, why now and how does it happen?
Will history repeat itself?
To give an answer, as thoroughly as possible, to this question I tried to define some of those steps that the countries of ASEAN should follow in order to effectively combat maritime piracy, terrorism widespread locally and organized crime; what could be the milestones in the process of construction of a shared legal system able to provide answers to many of the legal issues including the lack of a common legislation on maritime security. The watchword in the near future will have to be 'mutual legal assistance' in view of the implementation, in national legal corpora, of all those rules necessary to give effect to the directions contained in international conventions.
Eventually, I propose a different and further reading of all those theories that track in failure or in the great inefficiency of coordinating policies in the field of maritime safety, the proliferation of piracy. Though I substantially agree with some of those interpretations, two points are critical and deserves attention: the lack of a proper historical and historiographical perspective of analysis and what I have called the axiom of the ultimate solution
Design of microwave subsystems for radio astronomical receivers
Full text linkThe radio astronomical receivers are devices that they measure the radio emissions coming from celestial sources. Therefore, the aim of these devices is to convert the weak electromagnetic energy from space into a measurable electrical signal. The nature of the signal emitted by celestial sources imposes that such receivers must be broadband, very sensitive and designed to measure noise. In fact, the electromagnetic signal that the receivers must capture and measure, in addition to being very weak, is a random signal with components uncorrelated with each other, with different frequencies and with zero mean value (i.e. it is like the thermal noise produced by a resistor subject to a temperature). Therefore, the weakness and the peculiarity of these signals make the radio astronomy receivers other than those used in the telecommunications.
It is in this context that the work of my PhD thesis has been developed. Three different projects, that regard to the microwave subsystems of the radio astronomical receiver, have been treated.
The first project is focus on the development of a new configuration of broadband polarizer with very flat phase response in microtrip technology.
The second project is a feasibility study on the optics of a 3mm SIS receiver in order to install it in the Gregorian focus of the Sardinia Radio Telescope.
The third project is fully dedicated on the development of a high performance wideband feed-horn for a state-of-the-art multi-beam S-band (2.3 - 4.3 GHz) receiver to install in the primary focus of the Sardinia Radio Telescope
Management and modelling of battery storage systems in microGrids and virtual power plants
Full text linkIn the novel smart grid configuration of power networks, Energy Storage Systems
(ESSs) are emerging as one of the most effective and practical solutions to improve
the stability, reliability and security of electricity power grids, especially in presence
of high penetration of intermittent Renewable Energy Sources (RESs).
This PhD dissertation proposes a number of approaches in order to deal with
some typical issues of future active power systems, including optimal ESS sizing
and modelling problems, power
ows management strategies and minimisation of
investment and operating costs. In particular, in the first part of the Thesis several
algorithms and methodologies for the management of microgrids and Virtual Power
Plants, integrating RES generators and battery ESSs, are proposed and analysed
for four cases of study, aimed at highlighting the potentialities of integrating ESSs
in different smart grid architectures. The management strategies here presented are
specifically based on rule-based and optimal management approaches. The promising
results obtained in the energy management of power systems have highlighted
the importance of reliable component models in the implementation of the control
strategies. In fact, the performance of the energy management approach is only as
accurate as the data provided by models, batteries being the most challenging element
in the presented cases of study. Therefore, in the second part of this Thesis,
the issues in modelling battery technologies are addressed, particularly referring to
Lithium-Iron Phosphate (LFP) and Sodium-Nickel Chloride (SNB) systems. In the
first case, a simplified and unified model of lithium batteries is proposed for the
accurate prediction of charging processes evolution in EV applications, based on the
experimental tests on a 2.3 Ah LFP battery. Finally, a dynamic electrical modelling
is presented for a high temperature Sodium-Nickel Chloride battery. The proposed
modelling is developed from an extensive experimental testing and characterisation
of a commercial 23.5 kWh SNB, and is validated using a measured current-voltage
profile, triggering the whole battery operative range
Upper slope geomorphology of Sardinian southern continental margin, applications to habitat mapping supporting marine strategy
Full text linkThis work, framed within the Marine Strategy Framework Directive, is
focused on Sardinian southern continental margins marine habitat mapping. Aim of
this thesis is to produce predictive marine habitat mapping, starting from a detailed
geomorphologic study integrated with biological and oceanographic data coming
both from original direct surveys than from bibliographic data. Underwater remotely
operated vehicles (ROV), coupled with multibeam echo-sounder (MBES), enabled to
perform interpretative hypothesis validation, controlled sampling and detailed
observation of specific mesophotic habitats with noninvasive protocols, which are
particularly relevant for habitats of conservation interest. Marine habitat mapping
represents the best estimation of the distribution of habitats in a place and at a
particular time, this goal have been focused on target biocoenosis A4.26 –
“Mediterranean coralligenous communities moderately exposed to hydrodynamic
action” and A4.713 – “Caves and overhangs with Corallium rubrum”, as defined by
EUNIS classification (European Nature Information System), subsequently reunite
under the name of Coralligenous Biocoenosis for the mapping of which has been
reached a high level of confidence. Principal drivers for seabed habitat distributions
include the type of seabed substrate, depth, light availability and the energy of water
movements. For the very first time on Sardinian southern margin a multidisciplinary
approach has been used to study the relationship between biotic and abiotic
components of marine habitats and how seabed morphologic features influences
different benthic biocoenosis development styles, geomorphologic characteristics of
settlement for substrates could be important factors structuring benthic biodiversity,
by affecting sediment accumulation rates, bottom currents and, ultimately, the rates
of food supply. These biocoenosis hosts relevant commercially relevant species, as
the blue and the giant red shrimp which represent the most important demersal
resources for trawling fleet of Sardinia
Indagini strutturali e quantitative durante lo sviluppo del rene mediante l’utilizzo di elaborazione immagini
Full text linkThe attention of the scientific community about human intrauterine life is constantly growing. A very relevant aspect is the development of the kidney. Nephron number at birth has a relevant clinical importance with implications for long-term renal health. In recent years, the podocyte depletion hypothesis has emerged as an important concept in kidney pathology. Moreover, a variety of renal and urological abnormalities have been reported in subjects with chromosomal aberrations, such as Down syndrome and Beta Thalassemia. This study was aimed at verifying how human kidney structures, in particular glomerular shape and podocyte number, change during intrauterine life. Moreover, we evaluated if glomerular and tubular changes observed previously in adult subjects with Down syndrome and Beta Thalassemia might be related to changes in renal development in the early phases of embryogenesis. With these aims, fetal kidney sections were stained with H&E and digitally scanned; dimensional and quantitative analyses were performed using an algorithm developed in Matlab (Mathworks©). We first examined sixty-two normal subjects with gestational age ranging from 20 up to 41 weeks; subjects were subdivided into: fetuses (gestational age ≤ 24 weeks, n=5), preterms (gestational age ≥25 and ≤ 36 weeks, n=39), and at term (gestational age ≥ 37 weeks, n=18) infants. we found an average podocyte number of 1908 ± 645, 1394 ± 498 and 1126 ± 256 was respectively observed in fetuses, preterms and at term infants. A significant main effect (P=0.0051) of gestational age on podocyte number was observed with a significantly lower number in at term infants than in fetuses (P<0.001). An intra-group variability was also observed. To evaluate renal differences between Down syndrome fetuses and normal fetuses twenty-five subjects were examined. Subjects were subdivided into two groups: fetuses with Down syndrome (DS-fetuses, n=11) with a gestational age ranging from 13 up to 21 weeks, and healthy fetuses (N-fetuses, n=14) with a gestational age ranging from 9 up to 22 weeks. DS-fetuses showed slightly larger glomeruli as compared to N-fetuses. Moreover, glomeruli in DS-fetuses group were characterized by an enlarged Bowman’s space as compared to glomeruli in N-fetuses (p=0.0028 ). Differences in the nephrogenic zone width were also observed; DS-fetuses showed a greater width of this zone as compared with N-fetuses. Finally, with the end of evaluate differences in Beta Thalassemia, four beta-thalassemic fetuses and four normal fetuses at 13-15 weeks of gestational age were examined. The presence of enlarged glomeruli in the deep cortex, with the enlargement of the urinary space, has been observed in beta-thalassemic fetuses. Moreover, the presence of podocytes in urinary space, and of clusters of mesangial cells at the periphery of the glomerulus, was observed. An average podocyte number of 2494 ± 317 and 1546 ± 372 was
observed in normal fetuses and beta-thalassemic fetuses (P=0.0082) respectively. In conclusion, a decreasing trend in podocyte number during gestation in normal condition was observed; this decreasing trend of podocyte number suggests that podocytes might undergo a programmed cell death (apoptosis) or alternatively transdifferentiation during the glomerular growth; the high cell number in the first step of kidney development being correlated to the presence of both podocytes and podocyte precursors. In fetuses with Down Syndrome relevant morphological differences, such as glomerular abnormalities and expanded nephrogenic zone, have been found. Moreover, in fetuses with Beta Thalassemia relevant differences in architecture, in particular a deficiency in podocyte number, have been observed. These harmful changes in the glomerular structure may result in a nephron deficit, which may be associated with development of renal diseases and hypertension later in life. We hypothesize that the observed morphological anomalies could have significant implications for both the short- and long-term renal health of subjects with Down Syndrome and with Beta Thalassemia
Globalizzazione e sistema bancario europeo: Determinanti e impatto sulla redditività
Full text linkBased on a dataset that allows tracking banks across four Euro countries and across different modes of foreign entry, this study addresses the multi-nationalization strategies of European banks in the aftermath of the financial crisis of 2007. In this period the relevant regulatory activities that involved the banking sector and the high volatility of global economic and financial environment, represent the macro-institutional framework. In this context, bank hysteresis mechanisms among Euro countries are progressively attenuated, but still persist and affect ECB and its policy. In the analysis, we study the impact of country and firm level factors for bank multi-nationalization supported by a database of about 350 banks of the four major countries of the Euro area (Germany, France, Italy and Spain), for the period 2008-2014, on which statistical methods of panel regression are applied. We estimate a model with two specifications. In the first, we theoretically model the intensity of multi-nationalization of banks as a function of profitability, risk, and macroeconomics variables; in the second, we employ the intensity of multi-nationalization as impact-variable on bank profitability. Among the conclusions one seems the most important, the one linked to the prevailing negative relationship (dynamic in both directions) between profitability and intensive multi-nationalization process
Design and implementation of robust systems for secure malware detection
Full text linkMalicious software (malware) have significantly increased in terms of number and effectiveness
during the past years. Until 2006, such software were mostly used to disrupt
network infrastructures or to show coders’ skills. Nowadays, malware constitute a very
important source of economical profit, and are very difficult to detect. Thousands of
novel variants are released every day, and modern obfuscation techniques are used to
ensure that signature-based anti-malware systems are not able to detect such threats.
This tendency has also appeared on mobile devices, with Android being the most targeted
platform. To counteract this phenomenon, a lot of approaches have been developed
by the scientific community that attempt to increase the resilience of anti-malware systems.
Most of these approaches rely on machine learning, and have become very popular
also in commercial applications. However, attackers are now knowledgeable about these
systems, and have started preparing their countermeasures. This has lead to an arms
race between attackers and developers. Novel systems are progressively built to tackle
the attacks that get more and more sophisticated. For this reason, a necessity grows
for the developers to anticipate the attackers’ moves. This means that defense systems
should be built proactively, i.e., by introducing some security design principles in their
development. The main goal of this work is showing that such proactive approach can
be employed on a number of case studies. To do so, I adopted a global methodology that
can be divided in two steps. First, understanding what are the vulnerabilities of current
state-of-the-art systems (this anticipates the attacker’s moves). Then, developing novel
systems that are robust to these attacks, or suggesting research guidelines with which
current systems can be improved. This work presents two main case studies, concerning
the detection of PDF and Android malware. The idea is showing that a proactive approach
can be applied both on the X86 and mobile world. The contributions provided on
this two case studies are multifolded. With respect to PDF files, I first develop novel attacks
that can empirically and optimally evade current state-of-the-art detectors. Then,
I propose possible solutions with which it is possible to increase the robustness of such
detectors against known and novel attacks. With respect to the Android case study,
I first show how current signature-based tools and academically developed systems are
weak against empirical obfuscation attacks, which can be easily employed without particular
knowledge of the targeted systems. Then, I examine a possible strategy to build a
machine learning detector that is robust against both empirical obfuscation and optimal
attacks. Finally, I will show how proactive approaches can be also employed to develop
systems that are not aimed at detecting malware, such as mobile fingerprinting systems.
In particular, I propose a methodology to build a powerful mobile fingerprinting system,
and examine possible attacks with which users might be able to evade it, thus preserving
their privacy. To provide the aforementioned contributions, I co-developed (with the cooperation
of the researchers at PRALab and Ruhr-Universität Bochum) various systems:
a library to perform optimal attacks against machine learning systems (AdversariaLib),
a framework for automatically obfuscating Android applications, a system to the robust
detection of Javascript malware inside PDF files (LuxOR), a robust machine learning system
to the detection of Android malware, and a system to fingerprint mobile devices. I
also contributed to develop Android PRAGuard, a dataset containing a lot of empirical
obfuscation attacks against the Android platform. Finally, I entirely developed Slayer
NEO, an evolution of a previous system to the detection of PDF malware. The results
attained by using the aforementioned tools show that it is possible to proactively build
systems that predict possible evasion attacks. This suggests that a proactive approach
is crucial to build systems that provide concrete security against general and evasion
attacks