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On two problems related to the Laplace operator
Get PDFWe investigate maximization of the functional Ω → ε(Ω) where Ω runs in the set
of compact domains of fixed volume v in any Riemannian manifold (M; g) and
where ε(Ω) is the mean exit time from
of the Brownian motion. Concerning
this functional, we study its critical points and prove that they are harmonic
domains. We analyze the special case of the Coarea formula when we take a
Morse function. We investigate minimization and maximization of the principal
eigenvalue of the Laplacian under mixed boundary conditions in case the weight
has indefinite sign and varies in the class of rearrangements of a fixed function
g0 defined on a smooth and bounded domain Ω
in Rn. We prove existence
and uniqueness results, and in special cases, we prove results of symmetry and
results of symmetry breaking for the minimizer
Task allocation in the Internet of Things
Get PDFThe last few years have been involved by the technological revolution represented by the Internet of Things (IoT). The IoT vision aims to interconnect devices with different capabilities such as sensors, actuators, Radio Frequency Identification (RFID) tags, smart objects (e.g. smartphones), and servers, within the same heterogeneous network. The aim is to enable the network objects to dynamically cooperate and make their resources available, in order to reach a goal, i.e. the execution of one or more applications assigned to the network. As known since its invention, the Internet interconnects nodes with dissimilar characteristics without central authorities by introducing some simple yet effective protocols that allow for nodes' interoperability so that information is successfully exchanged and services are provided by servers to clients and among peers. Fortunately, the same happens among objects in the IoT so that interoperability is assured and the data sensed by objects distributed and connected to the physical world is now available for the benefit of the human users. The realization of the IoT paradigm relies on the implementation of systems of cooperative intelligent objects with key interoperability capabilities. However, to reach this goal, it's important to consider some key features that characterize many IoT objects: i) available nodes' resources (electrical energy, memory, processing, node capability to perform a given task) are often limited. This is the case, for example, of battery powered nodes, which have limited energy amounts. ii) sensors may provide information that is not unique but can be generated by set of different objects which for example are capable to sense the same physical measure of the same geographical. iii) the number of nodes in the IoT is quickly overcoming the number of hosts in the 'traditional' Internet and most of these have a low reliability due mostly to the mobility and energy. This entails for a new paradigm of communication according to which objects coordinate with the other objects in groups and provide a unified service to the external world (the application that requires the service), with the intent to distribute the load of the requested services according to specific community defined rules, which could be: lifetime extension, QoS (Quality of Service) maximization, reward maximization, or others. It is evident that an appropriate coordination of objects' resources utilization would consistently improve their performance. This foreword is necessary to introduce this thesis, which is defined as follows. Task allocation in the IoT: given the IoT paradigm and the requirements of IoT applications, the nodes involved in the execution of the same application should cooperate to reach the optimal allocation of tasks among them. They should execute tasks to reach the global application target and to satisfy the relevant requirements while optimizing the network performance in terms of resources used. This issue should be continuously addressed to dynamically adapt the system to changes in terms of application requirements and network topolog
Geni modificatori della Beta talassemia e sviluppo di un algoritmo per la predizione della severità clinica
Get PDFIntroduction
Many genetic factors influence Beta Thalassemia severity, recessive autosomal disorder with a
highly variable phenotype, beyond mutations in the causative Beta-globin gene (chr 11).
These factors are Alpha-globin genes defects and Fetal Hemoglobin modulators (HBG2:g.-
158C>T polymorphism, HBS1L-MYB intergenic region and the BCL11A gene).
Metods
In this work we studied an International cohort of 890 Beta Thalassemic patients to build a
predictive severity model of the pathology.
In order to achieve this goal we characterized 54 genetic variants at these loci robustly
associated with the amelioration of Beta Thalassemia phenotype. Subsequently we assessed,
using Cox proportional hazard analysis on a training set, the effect of these loci on the age at
which patients start regular transfusions. Finally we built a Thalassemia Severity Score and
validated it on a testing set.
Results
Discriminatory power of the model was high (C-index=0.705; R2=0.343) and the validation
conducted on the testing set confirmed its predictive accuracy with transfusion free
survival probability (p<0.001) and with transfusion dependency status (Area Under the
Receiver Operating Characteristic Curve=0.774, <0.001). Finally, an automatized online
calculation of the score was made available at http://tss.unica.it. Besides the accurate
assessment of genetic predictors effect, the presented results could be helpful in the
management of patients, both as a predictive score for screening and a standardized
scale of severity to overcome the major-intermedia dichotomy and suport clinical decision
Effetto della separazione materna sulla plasticità dei neuroni nell’ippocampo delle mamme e della prole
Get PDFNeuronal plasticity is the capability of neurons to change the structure, function and organization of neurons in response to new experiences. Behavioral studies in rodents, have shown that changes in the environment, in different periods of life, can lead to profound and lasting effects on neuronal plasticity as reflected by increased vulnerability or resilience to stress. Post-natal stress, such as maternal separation, have a deep impact not only for the offspring, but also for mothers, and lead to neuroendocrine, behavioral and structural changes in the brain. Neuroplasticity was evaluated both in mothers and offspring. Mothers were killed 21 days after delivery the day of the weaning and we analized density and morphology of dendritic spines and arborization of the dendritic tree in granule cells of hippocampus. Another goal of our study is to verify on the offspring, if stress induced by insufficient maternal care in the first 15 days of life increases the vulnerability to chronic stress conditions in adulthood. In this research, we used two experimental protocols of maternal separation, a) one group of pups was separated from their mothers for 15 min (short maternal separation), b) pups from the second group were separated for 3h (long maternal separation), every day from the 3rd to day 15th after birth respectively. The weaning day half of the rats belonging to the different groups was isolated for 60 days, while another group was isolated for 30 days then re-grouped for another 30 days. The results obtained were compared with those of rats never separated from their mothers (control), but subjected or not to social isolation. After sacrifice of offspring, we studied the density and morphology of dendritic spines, the arborization of dendritic tree and neurogenesis in the hippocampus. The results obtained in mothers showed that maternal separation reduced dendritic arborization in granule cells of hippocampus, and density of hippocampal dendritic spines is decreased in mothers after maternal separation. The results obtained in the offspring showed that social isolation induced a reduction of the arborization of the dendritic tree, variation of morphology and a reduction of the density of the dendritic spines, and a decrease of neurogenesis in animals not separated from the mother and in the separated ones. In rats subjected to re-group after 30 days of social isolation stress, the morphology and density of dendritic spines, arborization of the dendritic tree and the neurogenesis were completely reverted when compared to animals that have never been separated from their mothers (controls). In contrast, in animals subjected to maternal separation for 3 h, the social enrichment (re-grouped) failed to revert the effects of social isolation stress. In rats exposed to maternal separation for 15 min, social isolation for 60 days did not induce any change in the parameters studied. These results demonstrate that in the offspring, a short maternal separation of the animals in the first 15 days of life increase resilience to chronic stress during adult life. These data suggest that, in the offspring, high maternal care that result from a short maternal separation, increase resilience to chronic
stress during adulthood. On the contrary, a lower maternal care as a consequence of a long maternal separation, reduce resilience and increase vulnerability to chronic stress, impairs neuronal plasticity and effect cognitive functions and emotional state. These results show that maternal separation during early post-natal period, have a negative effects on neuronal plasticity, both in mothers and offsprin
Modelli di preannuncio delle piene in piccoli bacini ed incertezze legate alla densita' della rete pluviometrica.
Get PDFSmall catchments with fast hydrological responding geomorphology are commonly prone to Flash
Floods, which have to be predicted on the basis of meteorological forecast and radar nowcasting, rather
than continuously monitoring river water levels. Moreover, real-time rainfall observations at high
resolution in time and space are required to understand the watershed processes involved. However
small catchments are generally scarcely instrumented and only a sparse rain gauge network is available.
This work analyze different flood forecasting techniques and investigates their applicability on some
small catchments located in the east side of southern central Sardinia, where only a small number of
rain gauges is available. The first part of the work investigates the sensitivity and accuracy of
hydrological processes simulation of flooding events, using rain gauge networks of different density
with a statistical approach, by means of a long synthetic rainfall dataset simulated at high resolution in
time and space. Analyses on a set of 12 basins of different sizes, ranging from 15 up to 1800 km2, are
performed on the hydrological response of two simplified rainfall-runoff models: a lumped and a
distributed model. Results highlight a strong dependence of model performance with the event severity,
and show that even in very small basins and regardless of the model approach implemented, to
guarantee satisfying hydrological simulations, more rain gauges than those generally available are
required. A final comparison with a real case, although restricted to very few rain gauges, seems to
confirm the outcomes of the synthetic approach.
In the second part of the work, different Flash Flood forecasting techniques are tested on two small
basins (sizing 121 and 53 km2) provided with long observations at the rain gauges and hydrometric
stations. These techniques are classified in two main forecasting approaches: RTCM (Rainfall
Thresholds based on Conceptual Models) e RFTDM (Runoff and Frequency Thresholds based on
Distributed Modelling).
RTCM are strictly deterministic and provide rainfall thresholds for the entire basin through simple
operational curves, obtained by applying different event-based lumped models in inverse mode, and
taking into account only initial soil moisture content and event duration. These techniques are
operationally easy and could be rapidly transferred to other catchments. Meanwhile they provide fairly
good forecasting performances when base flow is rather low, even if an high false alarm rate is usually
exhibited.
RFTDM rely on a physically based distributed model which simulates continuously all hydrological
basin processes: in this work tRIBS (TIN based Real Time Integrated Basin Simulator) is applied for its
efficiency and computational speed. In particular two different approaches are proposed: Direct
method, in which the model is part of a forecasting chain running continuously in real-time and
simulating directly maximum floods on the basis of meteorological forecasts; Statistic method, through
flood frequency analyses (FFA) on observed and simulated discharges, provides probabilistic flood
predictions comparing occurrence frequencies rather than discharges. Results highlight a significant
reduction of false alarms with respect to the RTCM, preserving good prediction skills in different
operational conditions. Meanwhile, compared with the direct method, the expected forecasting
improvement using statistic method has not detected, regardless of the probability distribution chosen
for FFA. It’s important to note that Statistic method, notwithstanding the laborious setting, allows to
creating alert maps for flash flooding. Outcomes suggests to pay particular attention when using alert
maps produced by few rain gauges due to distortions induced through rainfall field sampling
Role of Hydroxy acid oxidase 2 (Hao2) in hepatocellular carcinoma
Get PDFBackground: Hydroxy acid oxidases are flavin mononucleotide (FMN)-dependent peroxisomal enzymes. Although it is unclear whether 2-hydroxy acid oxidases contribute to a general mechanism of fatty acid α-oxidation, these enzymes are capable of oxidizing a broad range of 2-hydroxy acids, ranging from glycolate to long chain 2-hydroxy fatty acids, such as 2-hydroxypalmitate, to 2-keto acids; this reaction results in hydrogen peroxide (H2O2) formation at the expense of molecular oxygen. Aim: Since no data concerning Hao2, a member of this family, and cancer are available in the literature, we analyzed the expression of this enzyme in mouse, rat and human hepatocellular carcinoma (HCC).
Results: Our microarray analysis, performed in the liver of rats subjected to the Resistant Hepatocyte (R-H) model, revealed that Hao2 was among the most down-regulated genes in HCCs developed, 14 months after initiation with a single dose of the hepatocarcinogen Diethylnitrosamine (DENA). Next, we investigated whether Hao2 down-regulation is an early event during liver carcinogenesis; to this aim, we analyzed the expression of Hao2 by qRT-PCR in preneoplastic lesions and HCCs generated 10 weeks, and 14 months after initiation, respectively. Interestingly, qRT-PCR showed down-regulation of Hao2 already in rat early preneoplastic lesions, especially in those positive for the putative progenitor cell marker KRT-19, considered to be the precursor of HCC in this model of hepatocarcinogenesis. Western blot analysis showed Hao2 down-regulation also at protein level.
To determine whether this down-regulation is a general phenomenon in liver tumorigenesis or is specific only for rat liver, we analyze the expression of Hao2 in a chemically-induced mouse model of hepatocarcinogenesis, consisting of a single injection of DENA followed by treatment with TCPOBOP (1,4-bis[2-(3,5-dichloropyridyloxy)] benzene), a ligand of the nuclear receptor CAR (Constitutive androstane receptor), that causes massive hepatomegaly and then HCC. Notably, similar to what found in rat HCC, Hao2 was strongly down-regulated also in TCP-induced mouse HCC. Finally, we investigated the expression levels of Hao2 in two distinct series of human HCCs. Interestingly, we found a strong down-regulation of Hao2 gene in human HCCs when compared to both normal and cirrhotic peri-tumoral liver. Furthermore, the levels of Hao2 were inversely correlated with time of recurrence, overall survival and occurrence of metastases. Conclusions: These results describe, for the first time, that Hao2 deregulation is severely impaired in HCCs generated in three different species and by different etiological agents. They also demonstrate that down-regulation of Hao2 is a very early event in the development of HCC, and may represent a useful diagnostic tool and a marker of poor prognosis
Valutazione degli aggiustamenti cardiocircolatori nel motociclismo classe enduro
Get PDFHemodynamic parameters, such as Cardiac Output (CO) and Stroke Volume (SV), have never
been studied in motorcycle racing. Probably because the measurement of these variables is
hampered by difficulties related to the particular environment of motorcycle performance,
which can be considered an extreme condition. Moreover, these parameters need the
availability of a non-‐‑invasive and reliable portable cardiovascular measurement systems.
Indeed, the only data available are about Heart Rate (HR), which increases to about 90-‐‑95% of
maximum, despite the supposed low energy requirements of motorcycle riding. The aim of
this study was to measure hemodynamics enduro -‐‑ motorcycling pilots during real
motorcycle race by means of portable impedance cardiograph.
Fifteen male elite motorcycle riders performing regional and national competitions on enduro
motorcycles were studied. Hemodynamics was assessed by means of a portable impedance
cardiograph (New Core, 2C Technologies Inc., Cagliari, Italy). Data were collected at rest,
throughout 10 minutes of motorcycle race at maximum speed possible and during passive
recovery. Also the blood lactate was measured at rest and after motorcycle race.
The comparison between rest and exercise showed a significant increase in hemodynamic
parameters. In detail, increments in both HR and SV were observed, thereby leading to a CO
elevation. Systemic Vascular Resistance (SVR) showed a significant reduction, while there
was an increase in systolic (SV/VET) and diastolic (SV/DT) flow index. Blood lactate
significantly increase after exercise. All parameters at recovery returned to rest levels, with
the exception of HR and SV/VET. Data obtained show that enduro motorcycle riding leads to
significant increments in both HR and SV. While the former fact was already known, the
latter is a new finding of the present investigation. The significant CO response can be the
consequence of a substantial increase in cardiac contractility which can be ascribed to a
sympathetic activation, as testified by the contemporary increase in HR. It is possible to
speculate that the heavy muscular work of the upper and lower limbs activates the exercise
pressor reflex, thereby causing sympathetic activation
Centri della conoscenza: dispositivi urbani per la creazione di Smart Cities
Get PDFThe PhD research investigates the meaning of the paradigm of Smart City, or Intelligent City, that, from several time, started to be discussed and applied in diverse urban contexts in the world. Smart Cities are characterized by the presence of pervasive and cooperating information and communication technologies. These technologies improve the efficiency of urban resources' management and increase relations and interaction within the urban space. However, a Smart City doesn't prescind from the fundamental role of citizens in the urban space's transformation and development, for this reason information and communication infrastructure are primarily a tool for intensifying connections and exchanges among citizens. In a sense, according with the vision proposed in this research, a Smart City is not exclusively a concept through which efficiency and resources optimization are emphasized, as in the visions that represent the city as a machine constituted of technological cooperating components, but definitively suggests a more holistic vision, which considers the complexity of contemporary cities. This approach underlines that the city is constituted of several interacting components, human and non-human, that together create a complex ecological system where the technological tools, proper of the Smart Cities, can facilitate its management, without adopting rigid standards that limit its free evolution.
The intensifying and multiplying of relations and interactions is therefore a concept at the base of the vision proposed by the Intelligent City model, where urban space's development is realized through new practices that enable novel opportunities for collaboration, based on a system of diffused knowledge. Context-knowledge is amplified by the information belonging to the digital space: urban space is increasingly constituted of digital elements that fundamentally contribute in shaping urban places, blending and integrating themselves into the physical space to which they relate and in which they are inscribed.
The development of approaches and methodologies capable of facilitating transformational processes of existing urban contexts towards more intelligent configurations can be a solution for the problems faced by contemporary cities. Defining solutions capable to imagine the space as a construct integrating physical and digital components, whose distinction is ever more labile, it is possible to develop new criteria that design and modified cities sustainably, favoring the increase of quality of life for citizens.
The research's unfolding has lead to observe how diffused knowledge and citizens' ability to cooperatively act are peculiar characteristics of intelligent cities, accelerated by pervasive urban technologies that facilitate the rapid diffusion on information and enable new forms of interaction through physical and digital space. Final results of the research define the Centers of Knowledge as conceptual devices that facilitate the creation of Smart Cities, suggesting material and immaterial forms with which generate intelligent urban contexts. The thesis is articulated into four chapters: in the first and second chapter principal theoretical references and best practices on Smart City are described; the third chapter contains the analysis conducted in Chicago, which is considered an optimum example of an intelligent urban context; in the forth chapter the concept of Center of Knowledge is explicated, describing the ways through which it can be shaped to develop new urban scenarios. Hopefully, the results of the research will provide a valid contribution in the rich debate around Smart Cities or Intelligent Cities, with the awareness that technological innovations and increasing experimentation of new modes of interactions produce rapid changes of the frame of references
Lingue e varietà linguistiche nel “nuovo cinema sardo”. Analisi di quattro film “letterari”
Get PDFThe subject of this thesis is the analysis of the language spoken by the characters of four films adapted from contemporary Sardinian novels: Sergio Atzeni’s Il figlio di Bakunìn directed by Gianfranco Cabiddu (1997); Maria Giacobbe’s Arcipelaghi directed by Giovanni Columbu (2001); Giuseppe Fiori’s Sonetàula directed by Salvatore Mereu (2008); Sergio Atzeni’s Bellas mariposas directed by Salvatore Mereu (2012). The main feature of these films is the employ of the local idioms - the Barbaricino and Campidanese varieties of Sardinian - alongside popular and regional Italian. Throughout a comparative analysis between novels and film dialogues, the research aims to investigate the most significant language changes in the passage from the literary to the audiovisual medium. The linguistic study of the “new Sardinian cinema” is also stimulating to comprehend the directors’ increasing attention to the Sardinian local dialects and their broadcasting, transmission and conservation. Cinema is subject to entertainment and show business rules, according to the audience’s tastes and interests, but it also mirrors the social, linguistic and cultural reality of the country
A semantic deconstruction of session types
Get PDFThis work investigates the semantic foundations of binary session types, by revisiting
them in the abstract setting of labelled transition systems. The main insights and
contributions are:
• a semantically unified approach to the study of session types and CCS processes
with synchronous and asynchronous semantics — the latter obtained with the
addition of unbounded buffers;
• a semantic approach to safety, based on a syntax-independent characterisation of
deadlock states, orphan messages and unspecified reception configurations;
• an I/O compliance relation between generic behaviours, that we demostrate to be
sound and complete w.r.t. safety in asynchronous session types;
• an I/O simulation relation between generic behaviours, which generalises the usual
syntax-directed notions of typing and subtyping, encompassing synchronous and
asynchronous session types;
• a proof-of-concept syntax-driven type system developed from the semantic setting
through a (partial) axiomatisation of I/O simulation.
This work extends the session types theory to some common programming patterns
which are not typically addressed in the session types literature, and aims at setting the
ground for further improvements