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Omyc analyzes reveal how plants respond to the symbiosis with the arbuscolar mycorrhizal fungi and symbiotic bacteria
No full textCurrently, there is an increasing body of evidence that the plant health depends on their tight associations with specialised soil microorganisms that have great effects on plant growth, protection and productivity. Among them, arbuscular mycorrhizal (AM) fungi (subphylum Glomeromycota, Schüßler et al., 2001) can establish a mutualistic association with most terrestrial plant species, including important agricultural and horticultural crops (Bonfante and Genre 2015). The AM symbiosis develops in roots, where the fungus colonizes the cortex supplying mineral nutrients to the plants in exchange of photosynthetic carbon compounds (Smith and Rweead, 2008). The exchanges between fungus and plant occur through specialized, branched and intracellular fungal structures called arbuscules (Bonfante and Anca 2009). Besides an improved mineral nutrition, plants colonized by AMF also receive other benefits, including an increased biomass, yield, and higher tolerance to biotic (pathogens) and abiotic (drought, salinity, heavy metals) stresses, leading to improved plant fitness (Gernns et al. 2001; Van der Heijden and Sanders 2002; Hildebrandt et al. 2007; Pozo and Azcón- Aguilar 2007; Aroca et al. 2008; Pozo et al., 2010; Lanfranco and Young 2012). Many plant roots also harbour a variety of soil beneficial bacteria that can benefit the plant by serving as plant-growth promoters. These bacteria, known as PGPR (plant-growth promoting rhizobacteria) can work as active rhizosphere components (Caballero-Mellado et al., 2007) or endophytic plant colonizers (Paungfoo-Lonhienne et al., 2014). The mechanisms that promote plant growth and development include: solubilization of minerals, nitrogen fixation, production of siderophores, plant growth regulators and organic acids, as well as protection by enzymes like chitinase, ACC-deaminase and glucanase (Berg, 2009; Glick et al., 2007; Hayat et al., 2010). These microorganisms can enhance biomass production and tolerance of the plants to several soil conditions as salinity, drought and heavy metals (Baharlouei et al., 2011). However, knowledge on the interaction of PGPR with many plants of agronomic interest is still scarce (Castanheira et al., 2015). Among plants colonized by AMF and PGPR is the bread wheat (Triticum aestivum), one of the most important food supply and the third-most widely grown crop worldwide, after rice and corn. Despite its economic and social importance, the effects of wheat symbiosis with the above microbes, considered individually or together, have never been investigated, in contrast to many other crop plants. Thanks to their benefits, AMF and PGPR can be used as natural biofertilizers and bioprotectors in integrated strategies for a sustainable and healthy wheat production. Furthermore, some AMF may contain endobacteria in their cytoplasm. These bacteria have a reduced genome, which lacks some crucial metabolic pathways and reveals dependence on the host for nutrients and energy (Ghignone et al. 2012). In exchange, they give many benefits to fungal host, sustaining its presymbiotic growth (Lumini et al., 2007; Salvioli et al., 2015), increasing the success of AMF sporulation and mechanisms for ROSdetoxification, and eliciting AMF innate immune responses (Salvioli et al., 2015). The beneficial effects of mycorrhizae in the rhizosphere are the result of synergistic interactions among all rhizosphere microbes, which are crucial for plant growth (Linderman, 1992). Thus, the relationship between AMF, their associated bacteria and plants provides a very interesting example of a metaorganism (Bosch and McFall-Ngai, 2011) and may be of great importance for sustainable agriculture.
In view of the above observations, during this thesis work three aims were pursued.
The first was the characterization of the molecular responses of wheat roots and leaves in presence of AMF alone and with a leaf pathogen to test whether AM fungi can be used as biofertilizer and bioprotector for enhancing plant growth and yield. We investigated the main pathways involved in enhancing plant biomass and mineral nutrition, and in promoting the bioprotective effect against a leaf pathogen. To address these issues, we combined phenotypic, metabolomic and molecular approaches, as detailed in Chapter 1.
The second aim was to analyze how proteome of wheat, in both roots and leaves, changes in response to colonisation by AMF and PGPR, considering single or double inocula. The purpose was to use these rhizosphere microbes in integrated strategies for a sustainable agriculture to improve plant health and yield. We wanted to achieve information about proteins that play pivotal roles in the molecular interactions of wheat with AMF and PGPR. In particular, this study has been set to obtain proteomic data providing a comprehensive picture of the intricate and yet mostly unknown cross-talk between wheat and AMF/PGPR. Methods and results of this study are reported in Chapter 2.
The third aim was to understand the effects of AMF endobacteria on both fungal and plant fitness. Thus, we analysed the proteomic profile of AMF spores with and without endobacteria, and after application of the synthetic strigolactone GR24 that, similarly to strigolactones produced by plant roots, is perceived by AM fungi, stimulating their energy metabolism and growth. The goal was to better explain with proteomics some morphological traits of the spore without bacteria. Moreover, we wanted to provide new insights into the molecular mechanisms mediating endosymbiosis and into how bacteria provide direct and/or indirect ecological benefits, not only for their fungal host, but also for the plant. A full account of this investigation is given in Chapter 3.
The research activities carried out during this thesis can be divided in the following three distinct, but interconnected parts.
In Chapter 1, we focused on the role of an AM fungus (Funneliformis mosseae) in the mineral nutrition of wheat, and on its potential protective effect against a leaf pathogen (Xanthomonas translucens). To address these issues, phenotypical, metabolomic and molecular approaches have been combined. Several studies have shown that both model and agricultural plants colonized by AMF often display an increased mineral nutrition and biomass, and higher tolerance to biotic and abiotic stresses. Despite wheat being one of the major global crops, its response to AM symbiosis has been poorly investigated so far. In this study, morphological observations indicated that AM wheat plants displayed a growth effect, in terms of biomass and grain yield, as well as a reduction of the lesions produced by the pathogen. To elucidate the molecular mechanisms underlying the mycorrhizal phenotype, we investigated the local and systemic changes of transcripts and proteins in roots and leaves during the bipartite (wheat-AM fungus) and tripartite (wheat-AM fungus-pathogen) interaction. Transcriptomic and proteomic profiling identified the main pathways (nutrient transport, primary metabolism, defence mechanisms, hormone regulation) involved in enhancing plant biomass, mineral nutrient content and in promoting the bio-protective effect against the leaf pathogen. Interestingly, the pathways were differentially regulated depending on the plant organ/microbe relationship. Mineral and amino-acid contents in roots, leaves and seeds, and protein oxidation profiles in leaves supported the omics data, providing new insightin the mechanisms exerted by AM symbiosis to confer stronger productivity and higher resistance to X. translucens in wheat.
In Chapter 2, we studied the mechanisms behind PGPR (Burkholderia graminis) - wheat interactions and the synergic interaction between B. graminis and F. mosseae on plant, through a proteomic analysis of wheat roots and leaves. Thus, we investigated the proteome alterations triggered in wheat by the dual inoculation PGPR + AMF compared to the sum of the effects elicited by single inocula. The main pathways identified concerned regulation of metabolic process, phytohormones, mineral transport and stress responses. In plants inoculated with B. graminis, the regulation of proteins involved in auxin pathways and the increase of N uptake efficiency may explain the observed root growth increase upon PGPR inoculation. Moreover, bacteria promoted the increase of several proteins involved in abiotic stress, in particular salt stress, and may contribute to improvement of the plant performance under stress conditions. Dual inoculation further led to the activation of many growth and defense-related proteins in roots and at systemic level. This result indicates that the dual inoculation in wheat enhances the biofertilizer and bioprotective effects of PGPR B. graminis and AMF F. mossae when co-inoculated. Phenotypic results also revealed that dual inoculation stimulates the growth of both roots and leaves of wheat plants with respect to the control.
Finally, in Chapter 3, we shed light on the interaction between AMF and their endosymbiont bacteria. RNA-seq analysis of the AMF Gigaspora margarita in the presence and absence of its endobacterium Candidatus Glomeribacter gigasporarum indicated that endobacteria are able to enhance fungal bioenergetics capacity. iTRAQ quantitative proteomics was used to identify differentially expressed proteins in G. margarita germinating spores with its endobacteria (B+), without endobacteria in the cured line (B-) and after application of the synthetic strigolactone GR24. Proteomic, transcriptomic and biochemical data identified several fungal and bacterial proteins involved in interspecies interactions. The greatest effects were on fungal primary metabolism and respiration, which was 50% higher in B+ than in B-. Quantification of carbonylated proteins indicated that the B- line had higher oxidative stress levels, which were also observed in two host plants. This study shows that endobacteria generate a complex interdomain network that affects AMF and fungal–plant interactions
Secure information sharing on Decentralized Social Networks.
No full textDecentralized Social Networks (DSNs) are web-based platforms built on distributed systems (federations) composed of multiple providers (pods) that run the same social networking service. DSNs have been presented as a valid alternative to Online Social Networks (OSNs), replacing the centralized paradigm of OSNs with a decentralized distribution of the features o↵ered by the social networking platform.
Similarly to commercial OSNs, DSNs o↵er to their subscribed users a number of distinctive features, such as the possibility to share resources with other subscribed users or the possibility to establish virtual relationships with other DSN users. On the other hand, each DSN user takes part in the service, choosing to store personal data on his/her own trusted provider inside the federation or to deploy his/her own provider on a private machine. This, thus, gives each DSN user direct control of his/hers data and prevents the social network provider from performing data mining analysis over these information.
Unfortunately, the deployment of a personal DSN pod is not as simple as it sounds. Indeed, each pod’s owner has to maintain the security, integrity, and reliability of all the data stored in that provider. Furthermore, given the amount of data produced each day in a social network service, it is reasonable to assume that the majority of users cannot a↵ord the upkeep of an hardware capable of handling such amount of information.
As a result, it has been shown that most of DSN users prefer to subscribe to an existing provider despite setting up a new one, bringing to an indirect centralization of data that leads DSNs to su↵er of the same issues as centralized social network services. In order to overcome this issue in this thesis we have investigated the possibility for DSN providers to lean on modern cloud-based storage services so as to o↵er a cloudbased information sharing service. This has required to deal with many challenges. As such, we have investigated the definition of cryptographic protocols enabling DSN users to securely store their resources in the public cloud, along with the definition of communication protocols ensuring that decryption keys are distributed only to authorized users, that is users that satisfy at least one of the access control policies specified by data owner according to Relationship-based access control model (RelBAC) [20, 34]. In addition, it has emerged that even DSN users have the same difficulties as OSN users in defining RelBAC rules that properly express their attitude towards their own privacy. Indeed, it is nowadays well accepted that the definition of access control policies is an error-prone task. Then, since misconfigured RelBAC policies may lead to harmful data release and may expose the privacy of others as well, we believe that DSN users should be assisted in the RelBAC policy definition process. At this purpose, we have designed a RelBAC policy recommendation system such that it can learn from DSN users their own attitude towards privacy, and exploits all the learned data to assist DSN users in the definition of RelBAC policies by suggesting customized privacy rules.
Nevertheless, despite the presence of the above mentioned policy recommender, it is reasonable to assume that misconfigured RelBAC rules may appear in the system. However, rather than considering all misconfigured policies as leading to potentially harmful situations, we have considered that they might even lead to an exacerbated data restriction that brings to a loss of utility to DSN users. As an example, assuming that a low resolution and an high resolution version of the same picture are uploaded in the network, we believe that the low-res version should be granted to all those users who are granted to access the hi-res version, even though, due to a misconfiurated system, no policy explicitly authorizes them on the low-res picture. As such, we have designed a technique capable of exploiting all the existing data dependencies (i.e., any correlation between data) as a mean for increasing the system utility, that is, the number of queries that can be safely answered. Then, we have defined a query rewriting technique capable of extending defined access control policy authorizations by exploiting data dependencies, in order to authorize unauthorized but inferable data.
In this thesis we present a complete description of the above mentioned proposals, along with the experimental results of the tests that have been carried out so as to verify the feasibility of the presented techniques
L'altro. Uno studio sull'individuazione femminile.
No full textThe female psychology dominates this third and final year of research, with a particular focus on the development of the female awareness through time. The topic has been critically analysed starting from Jung’s studies and postulating its alterity from the western culture. Highly relevant in the research the analysis of Neumann’s works. The evolution of the male/patriarchal awareness leads to a complete perception of the western culture and, consequently, to set the link with its opposite: the East and the female. The dissertation aims at affirming the relevance of the identification of that part of the human psyche which was buried in the deep unconscious with no rational reason. Jung laid the foundations for the subject. Based on his own theories, the research focuses on the female perspective by comparing it with the male one and highlighting analogies and discrepancies. Moving on, psychology originates from the human need to balance its unconscious, along with the exacerbation of the rational perspective during the 19th century. Moreover today’s lack of emotional involvement in the Christian symbolism produced a sense of uncertainty typical of the weakening of the sacred world. The goal is to recover spirituality by revaluing the visceral dimension, inherent to both the East and the female, of the human existence. And to set it, an examination of psychology and a series of learnings widely tagged as obscure and obsolete is required: mythology, alchemy, shamanism and tantric-yoga. Revaluating the psyche as human’s entirety links the scientific method and the irrational which characterized the archaic rituals and plays a crucial role in human’s self and social balance. The research does not result in a finish line. It rather discloses an alternative perspective on the psychological analysis of the modern society, which can help in postulating the female future evolution. To sum up, a change in perspective seems essential to unlock classical issues
Genomic aberrations in acute myeloid leukemia and significance of constitutional copy number variations in the development of post-transplant lymphoproliferative disorders.
No full textIn the first part of this study, 22 AML patients with Normal Karyotype were retrospectively analyzed by using OGT Hematological Cancer 8x60K CGH+ SNP array, in order to detect cryptic genomic aberrations.
11 out of 22 patients confirmed a normal genomic setting;11 out of 22 patients instead showed unexpected genomic imbalances, such as trisomies (+4, +8, +10, +13, +16) or monosomies (-7, -5q, -Y).
In addition to this large rearrangements, some patients showed Copy Number Variations (CNVs) containing genes involved in hematological process or tumorigenesis.
aCGH was also performed in a small group of patients with Complex karyotype in order to better define the cytogenetic results and to detect cryptic CNVs.
This study suggests a potential role for the use of aCGH in the clinical workup of AML patients with Normal karyotype in order to identify cryptic leukemic clones.
In the future this new approach will probably permit to better stratify the patients in risk category and make a more appropriate therapy.
In the second part of the study,22 renal-transplated patients were tested with OGT Oligoarray platform 4x180K CGH array in order to evaluate constitutional CNVs that might predispose to post-transplant lymphoproliferative disease.
Constitutional chromosomal regions involved in genomic imbalances (CNVs) affected mostly regions containing oncogenes or critical hematological regions,such as: 1p21.1,6p25.31, 14q32.33, and 16p11.2. These copy number variations are exclusively described in patients who develop PTLD and patients without PTLD but with High-EBV viral Load, and thus, at risk to develop the disease. This study permitted to identify new candidate loci involved in the predisposition of PTLD-development
Preconditioned fast solvers for large linear systems with specific sparse and/or Toeplitz-like structures and applications
No full textIn this thesis, the design of the preconditioners we propose starts from applications instead of treating the problem in a completely general way. The reason is that not all types of linear systems can be addressed with the same tools. In this sense, the techniques for designing efficient iterative solvers depends mostly on properties inherited from the continuous problem, that has originated the discretized sequence of matrices. Classical examples are locality, isotropy in the PDE context, whose discrete counterparts are sparsity and matrices constant along the diagonals, respectively.
Therefore, it is often important to take into account the properties of the originating continuous model for obtaining better performances and for providing an accurate convergence analysis. We consider linear systems that arise in the solution of both linear and nonlinear partial differential equation of both integer and fractional type. For the latter case, an introduction to both the theory and the numerical treatment is given.
All the algorithms and the strategies presented in this thesis are developed having in mind their parallel implementation. In particular, we consider the processor-co-processor framework, in which the main part of the computation is performed on a Graphics Processing Unit (GPU) accelerator.
In Part I we introduce our proposal for sparse approximate inverse preconditioners for either the solution of time-dependent Partial Differential Equations (PDEs), Chapter 3, and Fractional Differential Equations (FDEs), containing both classical and fractional terms, Chapter 5. More precisely, we propose a new technique for updating preconditioners for dealing with sequences of linear systems for PDEs and FDEs, that can be used also to compute matrix functions of large matrices via quadrature formula in Chapter 4 and for optimal control of FDEs in Chapter 6. At last, in Part II, we consider structured preconditioners for quasi-Toeplitz systems. The focus is towards the numerical treatment of discretized convection-diffusion equations in Chapter 7 and on the solution of FDEs with linear multistep formula in boundary value form in Chapter 8
Study of the molecular mechanism(s) underlying the antitumoral and highly pleiotropic functions of the human RNASET2 protein, a phylogenetically conserved extracellular RNase.
No full textThe RNASET2 gene encodes for the only human secreted acid ribonuclease of the T2 family. This gene maps in 6q27, a region that is consistently found rearranged in many solid and hematological tumors. Experimental data gathered in our laboratory have demonstrated the role of RNASET2 as a tumor suppressor gene which is endowed with several functions including chemotactic and possibly activating activities toward the monocyte/macrophage population. In a mouse xenograft model, we have recently reported that inoculation of human ovarian cancer-derived cells forced to overexpress RNASET2 led to the development of small, growth-suppressed tumors, characterized by a strong infiltrate of host-derived innate immunity cells, which have been identified as mainly M1 polarized macrophages. By contrast, control cells not expressing RNASET2, developed large, fast-growing tumors with no sign of macrophage infiltration.
Further investigations proved that recombinant RNASET2 (produced in either baculovirus or Pichia pastoris expression system) displayed a marked chemotactic activity in vitro, most likely dependent on a subfamily of G-protein Coupled Receptors associated with inhibitory G protein.
Taken together, these results led us to suggest that RNASET2-mediated in vivo tumor suppression is a non-cell-autonomous process which result in the recruitment of macrophages into the tumor mass.
Based on such evidences, we decided to further investigate the relation between RNASET2 and cells belonging to the monocyte-macrophages lineage.
Most of the experiments we planned to carry out involved the use of purified recombinant human RNASET2, hence, the first step of the project was the development of a reliable supply system.
Two different sources of production and purification of human RNASET2 protein were already available in our lab (P. pastoris and BEVS), however, a full exploitation of these reagents was precluded by several limitations inherent to both systems.
To overcome these limitation, we decided to focus our efforts on improving the P. pastoris expression system, which was more cost-effective and easier to handle in term of available facilities.
To solve the problem, we added another 6XHis tag to the construct coding for the human RNASET2 and managed to significantly improve the recovery of the input protein.
Considering the downstream applications of the purified human RNASET2, contamination of the preparation by metals (especially Ni, Cd, Zn) and endotoxin are important factor to control in order to properly assess a relationship between a specific treatment (in our case the addition of recombinant human RNASET2) and immune cell response. Applying the proper care in the preparation of the buffers and the handling of the sample we manage to achieve a low endotoxin content and an undetectable level of contamination by metals (Ni, Cd, Zn).
As previously mentioned, several studies have reported the consistent tumor suppressive role for several members of the T2 RNase protein family and the recruitment of immune cells seems to be involved in this suppression. In order to improve our knowledge of these functional features of T2 RNases and at the same time to evaluate their evolutionary conservation, we tested the role of human recombinant RNASET2 in the activation and recruitment of immune cells by injecting recombinant human RNASET2 in the body wall of Hirudo verbena a useful model system for our purposes.
After rRNASET2 injection, a significant increase in the production of collagen fibrils and a consequent remodeling of the muscle layers was observed. The resulting massive production of connective tissues is then used as a scaffold for immune cells migration and for proper orientation of growth of new vessels.
Injection of human recombinant RNASET2 was also shown to induce a massive migration of cells belonging to the macrophages lineage (characterized as HmAIF-1+ and CD68+ cells) within 24 h, coupled to the formation of new blood vessels.
The observed inflammatory response was specifically dependent of recombinant RNASET2 injection, since infiltrating macrophages and neo-vessel formation were not observed following injection of either PBS or rRNASET2 protein that was pre-incubated with a neutralizing anti-RNASET2 antibody.
Taken together, these data strongly suggest that rRNASET2 injection in leeches induces a marked inflammatory response characterized by macrophage recruitment.
The data gathered in our lab in several in vitro and in vivo experimental systems strongly suggest the occurrence of an RNASET2-based intercellular cross-talk, whose molecular mechanisms are nevertheless largely unknown.
As a first step in the logical sequence of events culminating in the above mentioned RNASET2 biological activities, we hypothesized the occurrence of a putative receptor for RNASET2.
The common idea behind all our approaches was to covalently link RNASET2 (either the endogenous protein or the human recombinant protein) to any interactor and, after purification of the complex, to perform a MS analysis to characterize the interactants.
As a first approach, we carried out chemical modification of purified recombinant RNASET2 with different compounds (SDA, LC-SDA, Sulfo SDA, Sulfo LC-SDA) in order to add a diazirine ring to all primary ammines of the target protein. The resulting modified RNASET2 protein could then, in principle, be crosslinked to all electron donors available following UV light activation. The modified protein was then incubated with RNASET2-silenced OVCAR3 cells and analyzed by western blot following UV exposure. Despite several attempts with this approach, we could not observe any shift in the molecular weight of RNASET2.
Considering that most of the result obtained show evidence of a tropism of RNASET2 for cells belonging to the monocyte/macrophage lineage, with our last approach we tested a promyelocytic cell line. We exposed the U937 cells preincubated with rRNASET2 to a chemical crosslinkers (BS3) able to covalently link two or more proteins in close proximity. By this approach we managed to see a shift in the molecular weight of the RNASET2, but unfortunately in the next step we couldn't purify any detectable complex.
Considering that TAMs are usually forced by the tumor cells to acquire an M2-polarized pro-tumorigenic phenotype, a key finding of our research group is that tumor xenografts that are suppressed in their growth following RNASET2 overexpression display a strong infiltration of M1-polarized macrophages which are known to show anti-tumorigenic properties. Therefore, the last part of this PhD program was dedicated to investigate the molecular/cellular bases of the interaction between RNASET2 and immune cells, in particular to describe a possible involvement of this protein in driving macrophages polarization.
The main idea was to develop a system to reliably produce M0, M1 and M2 macrophages that could then be used to test the effect of RNASET2 looking at their transcriptional profile.
To this end, we chose a well-known cellular model (THP-1 cell line) and, in order to remove any bias from future analysis, we selected a pool of cells silenced for the expression of RNASET2.
THP-1 is a promyelocytic cell line therefore in order to effectively produce polarized cells we needed to differentiate it into macrophages. Using the guidelines found in the literature we managed, by treating THP-1 cells with PMA 5 ng/ml for 48 h, to produce M0 macrophages.
Subsequently, we developed a protocol to effectively drive naive macrophages to either M1 or M2 phenotype. We followed the suggested guidelines and assessed the efficacy of our system by testing a small panel of known marker of polarization (TNF, CXCL10, CCL19 for M1 polarization and CCL22, MRC1, MSR1 for M2 polarization).
Considering the final aim of the developed assay, we tested whether our macrophages, especially M1 and M2, still retained the plasticity to change their profile according to external stimuli. M0 cells were exposed to both M1 and M2 stimuli; the resulting profile was neither M1 nor M2, suggesting that the cells prepared with our system still retained the characteristic/desired plasticity to properly respond to external signals.
The data gathered so far support the idea that the system developed might be useful to study the involvement of RNASET2 in macrophages polarization.
To summarize, during these three years of my PhD program I was involved in many different parts of a project aimed at deepen our understanding of the mechanism underlying RNASET2 tumor suppression. Although I wasn't able to identify any putative receptor for RNASET2 experimental evidence suggests the existence of a molecular mechanism involved in the “sensing” of the RNASET2 protein. Further studies are clearly needed in order to clarify this issue and the recent finding of RNASET2-containing exosomes is a promising avenue of investigation.
The data collected in Hirudo strengthen our hypothesis of a close relationship between Immune cells (in particular cells belonging to monocyte/macrophages lineage) and RNASET2 but, more importantly these
results open new research opportunities to study the involvement of T2 ribonucleases in inflammation. From a strictly technical point of view, I was able to improve the system of production and purification of the recombinant human protein, making it possible the use of RNASET2 in conditions previously inaccessible (interaction with immune cells/injection in organism).
To conclude I contributed to laid the bases for future studies aiming at dissecting the involvement of RNASET2 in macrophages polarization and I did it by developing a simple assay that might test the "polarizing potential" of RNASET2 (but potentially of any compound)
Il diritto alla terra dei popoli indigeni in prospettiva comparata. Il caso dell’America Latina. The right to traditional land of indigenous peoples in a comparative perspective. The Latin American case.
No full textThe dissertation aims to investigate the problematic question of the return of indigenous peoples in their historical lands and the deep connection between their culture and their political institutions with environment, nature and tradition, as it is actually introduced by international law and public law in the different countries where the indigenous presence is relevant.
The definition of "indigenous people" and its development in the international scenario in the last decades has characterized a new consideration about the rights of indigenous peoples, whose self-determination is otherwise connected to a specific land, occupied and translated from generations and synonymous of an unique identity (the so-called anthropological concept of "ancestral land"). It caused a re-interpretation of the relationship between lands and indigenous peoples, either providing the reintegration of indigenous in their ancestral lands (once expropriated by State authorities), either considering a unified point-of-view on land/earth as a common, in which natural resources should be managed by communities (referring to the concept of "Mother Earth").
The thesis investigates the international protection of the rights of indigenous peoples and its development in history, considering the protection extended by the ILO Conventions (1957/n.105 and 1989/n.169) and the UN Declaration on the Rights of Indigenous Peoples 2007 and the influence of the Cobo Report in international and national law. It also deals with some "virtuous" cases involving a special relation between national institutions and indigenous communities, in order to create a legal paradigm of protection to indigenous peoples and their historical rights (i.e., the cases of North-American natives, Australian aborigines, New Zealand maoris and Scandinavian saamis).
The protection of indigenous peoples and their traditional lands becomes a particularly relevant fact in the Latin-American contest for the peculiar complexity (historically based) of the relationship with natives and the important phase of political and democratic transition in '80s-'90s. New Constitutions (or constitutional reviews), elaborated in this period in the Latin-American region, have been affected by the theory of Nuevo Constitucionalismo, that totally disagrees with the western constitutionalism and with the theory of legal positivism. According to this new constitutional theory, indigenous customary law is considered among the basics of national law, granted and protected by the Constitution. It provides that the natives are seen as an entity per se, recognized by the State (and not forcedly integrated into the European inspired reality, as in the past years), entitled to possess their ancestral lands and to claim their own rights (even the cultural ones). In order to this renewal, the indigenous costumbre becomes law of the State. So on, the common managing on lands and natural resources are to be in accordance with the indigenous harmonic relationship with nature. Earth, or Mother Earth (Tierra Madre or, using a quechua term, Pacha Mama), becomes effectively a common.
The thesis deals with the political passage of transition to democracy in Latin-American region and with the construction of a new constitutionalism, affected by the consideration of collective rights and the protection of social and cultural minorities. It also provides to do a general framework of the recent Latin-American constitutions and their protection of indigenous rights and indigenous property of lands (with a specific consideration about the Andean constitutionalism in Bolivia and Ecuador and the revolutionary entrance of customary laws). Then, the analysis focuses on the case of Paraguay and Argentina, whereas the new constitutional laws (Constitution of Paraguay in 1992 and constitutional review in Argentina in 1994) have expressively contemplated the recognition and the protection of the indigenous right to historical lands, also considering the development of the protection in the political and legal history of the States.
Finally, the research aims to focus on the role of the Inter-American Court of Human Rights in creating a constitutional and international parameter of protection of indigenous land right and providing the return of indigenous communities in their traditional lands. The decisions of the Inter- American Court are actually a bridge for the incorporation of indigenous rights in national legislations, providing a constitutional-oriented jurisprudence and giving an important signal for the international debate
L'alimentazione nell'anziano dal domicilio alla lungodegenza. Etica ed appropriatezza dell'apporto nutrizionale nei percorsi assistenziali. Feeding in the elderly from domicile to long term care. Ethics and appropriateness of nutritional support in care paths.
No full textBACKGROUND: The World Health Organization estimates that the population over the age of 60 is growing steadily and will double by the year 2050.
In the elderly there are physiological modifications but incorrect nutrition can produce a state of malnutrition that may result in excessive morbidity and mortality or an alteration in the quality of life. Therefore, the diagnosis and therapy of malnutrition are one of the key moments of elder care.
Recovery of at least 5% of body weight can reduce the incidence of morbidity and mortality in institutionalized patients.
There are several studies in the literature on the state of malnutrition in the elderly, but no one takes into account all the possible risk factors and variations that may arise in nutritional status prior to entering in long term care and later.
OBJECTIVE: To assess the state of nutrition and risk factors for malnutrition of patients at the time of entry into a long-term care. Monitor dietary intake during hospitalization and check for changes in nutritional status at a distance of one month from the beginning of institutionalization. This path is promoted:
1) as a means of improving the quality of care,
2) as a means to optimize the outcome of interventions on patients,
3) to discourage and detect ineffective or dangerous interventions,
4) to improve and ensure the adequacy of care,
5) to identify areas of clinical practice where there is insufficient evidence,
6) to help balance costs and results.
MATERIALS AND METHODS: A cohort study was developed on eight long term care in which were the same menu, raw materials and methodologies. The population of study is constituted by the new patients of more than 65 years, males or females indifferently and who have signed informed consent to the processing of their data in anonymous form for statistical purposes. People in enteral nutrition were excluded from the study. The collected data encompasses the characteristics of patients and their conditions at time 0, their eating behavior and conditions after a month in long term care (time 1). Data were extracted from clinical diaries, assessment scales and laboratory examinations.
RESULTS: The general characteristics of patients (sex, age, level of instruction and provenance), patient conditions at time 0 and time 1 (general conditions, state consciousness, most frequent pathologies, pharmacotherapy, oral cavity conditions, dysphagia, decubitus lesions, walking, cognitive level -MMSE-), nutritional evaluation at time 0 and time 1 (weight, body mass index, weight variations, use of a diet, use of dietary supplements, malnutrition risk -MUST-) and laboratory examinations evaluation at time 0 and time 1 (hemoglobin, absolute lymphocytes, serum iron, folic acid, vitamin B12, vitamin D, calcium, albumin, total cholesterol, glucose).
CONCLUSIONS: On the basis of analyzed data, it is concluded that proper nutrition in older people does not go through the construction of a pyramid process but by the creation of a harmonic gear consisting of doctors, chefs, nutritionists, professional educators, caregivers and institutions
Development of a silicon photomultiplier based innovative and low cost positron emission tomography scanner.
No full textThe Silicon Photomultiplier (SiPM) is a state-of-the-art semiconductor photodetector consisting of a high density matrix (up to 104) of independent pixels of micro-metric dimension (from 10 μm to 100 μm) which form a macroscopic unit of 1 to 6 mm2 area. Each pixel is a single-photon avalanche diode operated with a bias voltage of a few volts above the breakdown voltage. When a charge carrier is generated in a pixel by an incoming photon or a thermal effect, a Geiger discharge confined to that pixel is initiated and an intrinsic gain of about 106 is obtained. The output signal of a pixel is the same regardless of the number of interacting photons and provide only a binary information. Since the pixels are arranged on a common Silicon substrate and are connected in parallel to the same readout line, the SiPM combined output response corresponds to the sum of all fired pixel currents. As a result, the SiPM as a whole is an analogue detector, which can measure the incoming light intensity.
Nowadays a great number of companies are investing increasing efforts in SiPM detector performances and high quality mass production. SiPMs are in rapid evolution and benefit from the tremendous development of the Silicon technology in terms of cost production, design flexibility and performances. They have reached a high single photon detection sensitivity and photon detection efficiency, an excellent time resolution, an extended dynamic range. They require a low bias voltage and have a low power consumption, they are very compact, robust, flexible and cheap. Considering also their intrinsic insensitivity to magnetic field they result to have an extremely high potential in fundamental and applied science (particle and nuclear physics, astrophysics, biology, environmental science and nuclear medicine) and industry.
The SiPM performances are influenced by some effects, as saturation, afterpulsing and crosstalk, which lead to an inherent non-proportional response with respect to the number of incident photons. Consequently, it is not trivial to relate the measured electronic signal to the corresponding light intensity. Since for most applications it is desirable to qualify the SiPM response (i.e in order to properly design a detector for a given application, perform corrections on measurements or on energy spectra, calibrate a SiPM for low light measurements, predict detector performance) the implementation of characterization procedures plays a key role.
The SiPM field of application that has been considered in this thesis is the Positron Emission Tomography (PET). PET represents the most advanced in-vivo nuclear imaging modality: it provides functional information of the physiological and molecular processes of organs and tissues. Thanks to its diagnostic power, PET has a recognized superiority over all other imaging modalities in oncology, neurology and cardiology. SiPMs are usually successfully employed for the PET scanners because they allow the measurement of the Time Of Flight of the two coincidence photons to improve the signal to noise ratio of the reconstructed images. They also permit to perfectly combine the functional information with the anatomical one by inserting the PET scanner inside the Magnetic Resonance Imaging device.
Recently, PET technology has also been applied to preclinical imaging to allow non invasive studies on small animals. The increasing demand for preclinical PET scanner is driven by the fact that small animals host a large number of human diseases. In-vivo imaging has the advantage to enable the measurement of the radiopharmaceutical distribution in the same animal for an extended period of time. As a result, PET represents a powerful research tool as it offers the possibility to study the abnormalities at the origin of a disease, understand its dynamics, evaluate the therapeutic response and develop new drugs and treatments. However, the cost and the complexity of the preclinical scanners are limiting factors for the spread of PET technology: 70-80% of small-animal PET is concentrated in academic or government research laboratories.
The EasyPET concept proposed in this Thesis, protected under a patent filed by Aveiro University, aims to achieve a simple and affordable preclinical PET scanner. The innovative concept is based on a single pair of detector kept collinear during the whole data acquisition and a moving mechanism with two degrees of freedom to reproduce the functionalities of an entire PET ring. The main advantages are in terms of the reduction of the complexity and cost of the PET system. In addition the concept is bound to be robust against acollinear photoemission, scatter radiation and parallax error. The sensitivity is expected to represent a fragility due to the reduced geometrical acceptance. This drawback can be partially recovered by the possibility to accept Compton scattering events without introducing image degradation effects, thanks to the sensor alignment.
A 2D imaging demonstrator has been realized in order to assess the EasyPET concept and its performance has been analyzed in this Thesis to verify the net balance between competing advantages and drawbacks. The demonstrator had a leading role in the outreach activity to promote the EasyPET concept and a significant outcome is represented by the new partners that recently joined the collaboration. The EasyPET has been licensed to Caen S.p.a. and, thanks to the participation of Nuclear Instruments to the electronic board re-designed, a new prototype has been realized with additional improvements concerning the mechanics and the control software. In this Thesis the prototype functionalities and performances are reported as a result of a commissioning procedure. The EasyPET will be commercialized by Caen S.p.a. as a product for the educational market and it will be addressed to high level didactic laboratories to show the operating principles and technology behind the PET imaging.
The topics mentioned above will be examined in depth in the following Chapters according to the subsequent order. In Chapter 1 the Silicon Photomultiplier will be described in detail, from their operating principle to their main application fields passing through the advantages and the drawback effects connected with this type of sensor. Chapter 2 is dedicated to a SiPM standard characterization method based on the staircase and resolving power measurement. A more refined analysis involves the Multi-Photon spectrum, obtained by integrating the SiPM response to a light pulse. It exploits the SiPM single photon sensitivity and its photon number resolving capability to measure some of its properties of general interest for a multitude of potential applications, disentangling the features related to the statistics of the incident light. Chapter 3 reports another SiPM characterization method which implements a post-processing of the digitized SiPM waveforms with the aim of extracting a full picture of the sensor characteristics from a unique data-set. The procedure is very robust, effective and semi-automatic and suitable for sensors of various dimensions and produced by different vendors. Chapter 4 introduces the Positron Emission Tomography imaging: its principle, applications, related issues and state of the art of PET scanner will be explained. Chapter 5 deals with the preclinical PET, reporting the benefits and the technological challenges involved, the performance of the commercially available small animal PET scanners, the main applications and the frontier research in this field. In Chapter 6 the EasyPET concept is introduced. In particular, the basic idea behind the operating principle, the design layout and the image reconstruction will be illustrated and then assessed through the description and the performance analysis of the EasyPET proof of concept and demonstrator. The effect of the use of different sensor to improve the light collection and the coincidence detection efficiency, together with the analysis of the importance of the sensor and the crystal alignment will be reported in Chapter 7. The design, the functionalities and the commissioning of the EasyPET prototype addressed to the educational market will be defined in Chapter 8. Finally, Chapter 9 contains a summary of the conclusions and an outlook of the future research studies
Temporal properties of counter propagating twin photons
No full textTwin photon pairs generated through parametric downconversion (PDC) in a χ 2 medium is one of the most widely used source of entanglement. We focus here on a non-conventional geometry in which one of the twin photons propagates in the opposite direction with respect to the pump beam, exploiting quasi-phase-matching in a periodically poled crystal. Through predicted almost 50 years ago, this new PDC configuration has been realized experimentally only recently [1] thanks to new fabrication techniques achieving the required sub-micrometer poling period. Because of the presence of distributed feedback, the optical system has been shown to behave as a Mirrorless Optical Parametric Oscillator (MOPO) and exhibits peculiar spectral properties which strongly differ from those found in more common geometries involving co-propagating beams. In this work we provide a detailed analysis of the correlation and coherence properties of counter-propagating twin beams both in the purely spontaneous regime and in the neighborhood of the MOPO threshold. We consider on the on side the regime of spontaneous pair production where the characteristic narrow band of the counter-propagating twin beams offers the unique opportunity of generating heralded single photon states with a high degree of purity, a relevant property for applications in quantum communication. In this context, we investigate how the degree of separability of the twin photon state varies with the pump pulse duration τp. We find that two well separated time scales characterize the system dynamics: a short time scale τgvm, in the picoseconds range, corresponding to the typical temporal delay of co-propagating waves due to group-velocity mismatch, and a much longer time scale τgvs associated with the temporal separation of counter-propagating waves. Such a difference of time scales occurs naturally in the counterpropagating configuration, for basically any kind of material and tuning condition. Because of this same feature, counter-propagating twin photons in a pure state can in principle be heralded at any wavelength by choosing the appropriate poling period. We show that a high degree of separability can be achieved when the pump pulse duration satisfy the condition τgvm ≪ τp ≪ τgvs, as put in evidence from the evaluation of Schmidt number as a function of the pump pulse duration which reaches a minimum close to unity in this region. The separability is lost in the nearly monochromatic limit ( τp ≫ τgvs ) as well as for ultra-short pulses ( τp ≪ τgvm ), where the entanglement between the signal and idler frequencies can be inferred by the non factorable shape of the spectral biphoton amplitude. We offer a physical interpretation of such a behaviour, and a detailed analysis of the Schmidt number characterizing the entanglement of the state. We also considered a completely different regime of operation, close to the MOPO threshold, where the combined effect of stimulated PDC and distributed feedback affects dramatically the property of coherence of the field. Our analysis put in evidence a progressive narrowing of both the spectral twin beam correlation and the intensity spectra as the pump field intensity approaches its threshold value. This translates into a drastic increase of the correlation and coherence times in the temporal domain, a feature which can be attributed to the critical slowing down of the fluctuation dynamics characterizing the transition toward coherent emission occurring at the MOPO threshold. Furthermore, we investigate the potentiality of the source to generate squeezing and EPR type correlations in the threshold vicinity. In this regards, the obtained results shows that the system displays a behaviour which is very similar to that found in standard optical parametric oscillators enclosed in a resonant cavity. In the last part of the work, we present some preliminary results from numerical simulations illustrating the transition above the MOPO thresholds. We also take into account non collinear PDC emission, showing explicitely that the spatial and the temporal degrees of freedoms of the emitted twin photons are almost uncoupled. This feature strongly distinguish the counter-propagating configuration from standard co-propagating geometries where the phase-matching mechanism usually leads to strong angular dispersion