10081 research outputs found
Sort by
Cross-sensors analysis of multispectral Earth observation data for environmental monitoring
Get PDFTime Series Analysis of multispectral satellite data offers an innovative way to extract valuable information of our changing planet. This is now a real option for scientists thanks to data availability as well as innovative cloud-computing platforms, such as Google Earth Engine. The integration of different missions would mitigate known issues in multispectral time series construction, such as gaps due to clouds or other atmospheric effects. With this purpose, harmonization among Landsat-like missions is possible through statistical analysis.
This research offers an overview of the different instruments from Landsat and Sentinel missions (TM, ETM, OLI, OLI-2 and MSI sensors) and products levels (Collection-2 Level-1 and Surface Reflectance for Landsat and Level-1C and Level-2A for Sentinel-2). Moreover, a cross-sensors comparison was performed to assess the interoperability of the sensors on-board Landsat and Sentinel-2 constellations, having in mind a possible combined use for time series analysis.
Firstly, more than 20,000 pairs of images almost simultaneously acquired all over Europe were selected over a period of several years. The study performed a cross-comparison analysis on these data, and provided an assessment of the calibration coefficients that can be used to minimize differences in the combined use. Four of the most popular vegetation indexes were selected for the study: NDVI, EVI, SAVI and NDMI. As a result, it is possible to reconstruct a longer and denser harmonized time series since 1984, useful for vegetation monitoring purposes.
Secondly, the spectral characteristics of the recent Landsat-9 mission were assessed for a combined use with Landsat-8 and Sentinel-2. A cross-sensor analysis of common bands of more than 3,000 almost simultaneous acquisitions verified a high consistency between datasets. The most relevant discrepancy has been observed in the blue and SWIRS bands, often used in vegetation and water related studies. This analysis was supported with spectroradiometer ground measurements
NB-IoT via non terrestrial networks
Get PDFMassive Internet of Things is expected to play a crucial role in Beyond 5G (B5G) wireless communication systems, offering seamless connectivity among heterogeneous devices without human intervention. However, the exponential proliferation of smart devices and IoT networks, relying solely on terrestrial networks, may not fully meet the demanding IoT requirements in terms of bandwidth and connectivity, especially in areas where terrestrial infrastructures are not economically viable.
To unleash the full potential of 5G and B5G networks and enable seamless connectivity everywhere, the 3GPP envisions the integration of Non-Terrestrial Networks (NTNs) into the terrestrial ones starting from Release 17. However, this integration process requires modifications to the 5G standard to ensure reliable communications despite typical satellite channel impairments.
In this framework, this thesis aims at proposing techniques at the Physical and Medium Access Control layers that require minimal adaptations in the current NB-IoT standard via NTN. Thus, firstly the satellite impairments are evaluated and, then, a detailed link budget analysis is provided.
Following, analyses at the link and the system levels are conducted. In the former case, a novel algorithm leveraging time-frequency analysis is proposed to detect orthogonal preambles and estimate the signals’ arrival time. Besides, the effects of collisions on the detection probability and Bit Error Rate are investigated and Non-Orthogonal Multiple Access approaches are proposed in the random access and data phases.
The system analysis evaluates the performance of random access in case of congestion. Various access parameters are tested in different satellite scenarios, and the performance is measured in terms of access probability and time required to complete the procedure. Finally, a heuristic algorithm is proposed to jointly design the access and data phases, determining the number of satellite passages, the Random Access Periodicity, and the number of uplink repetitions that maximize the system's spectral efficiency
Physical activity and osseointegration: "step forward" to improve the quality of life of a trans-femoral amputee person
Get PDFLower limb amputation is an event that inevitably changes the lifestyle of the person with a significant impact on quality of life. The socket-type prosthesis entails that the residual limb is in direct contact with the socket which often implies numerous disadvantages. Osseointegrated prosthesis is a solution that avoids skin problems because not include the presence of the socket. In this type of prosthesis, a stem is surgically inserted inside the medullary canal and connected with the external prosthetic limb.
Therefore, this thesis aims to highlight and explore the main strengths and problems of osseointegrated prostheses and to examine the role of physical activity, with attention to functional capacity and bone quality. The objectives of the thesis will be developed through 5 studies: (I) A gait analysis of a 44 years-old male patient who underwent surgery for the implantation of an osseointegrated prosthesis; (II) A systematic review to investigate the state of stump bone quality in patients with limb amputations; (III) A systematic review of the technologies involved in such devices has been carried out to identify the most fruitful ones in improving bone quality; (IV) A systematic review investigating the topic of physical activity and bone turnover biomarkers; (V) A systematic review to investigate the effects of physical activity interventions combined with drug treatments on bone biomarkers in people with osteopenia and osteoporosis.
The integrated prosthesis is a good solution for people with lower limb amputation who cannot use their traditional socket-type prosthesis. Although many objectives have already been achieved, there are still many aspects that we can improve. These include the creation of a multidisciplinary path that support patients along their path, with particular attention to the pre-surgery and the post-rehabilitation phase that is still lacking even if of fundamental impact in determining the quality of life
Gandhi in the Black Atlantic: geographies, movements, concepts
Get PDFQuesto lavoro ricostruisce l'uso strategico di Gandhi come “significante” nel pensiero politico dell'Atlantico Nero, nella lotta contro la supremazia bianca e nei processi di decolonizzazione. Le pratiche discorsive che hanno stretto alleanze metaforiche con il movimento gandhiano sono evidenziate come un mezzo con cui il discorso politico nero attraversa la linea di separazione tra metropoli e colonie, e sovverte la costruzione spaziale della modernità. L’analisi spazia dall'indomani della Prima guerra mondiale alla seconda metà degli anni Cinquanta. Questa parte di Secolo breve fu caratterizzata dalle due guerre mondiali, dalla Lega contro l'imperialismo e dai congressi panafricani - importanti punti di svolta che consolidarono la consapevolezza di un'esperienza comune di oppressione e sfruttamento razziale. La ricerca si concentra sui circuiti e movimenti editoriali e associativi, come i congressi panafricani (1919-1945), il movimento “New Negro”, l’UNIA di Marcus Garvey, il sindacalismo nero e i movimenti di liberazione africani - in particolare la Positive Action in Ghana, il movimento zikista in Nigeria e la Defiance Campaign in Sud Africa. Nel complesso quadro di gerarchie e idiosincrasie dell'Atlantico Nero, gli scarti semantici dell'uso di Gandhi come tropo politico sono connessi con diverse prospettive e visioni di solidarietà.This work reconstructs the strategic use Gandhi as a multi-layered “signifier” in the political thought of the Black Atlantic, intersecting the struggle against white supremacy and the decolonization processes. The discursive practices that have made metaphorical alliances with the Gandhian movement are highlighted here as a means by which the political discourse of the African diaspora crisscrosses and subverts the separation line between metropoles and colonies as a spatial construction of modernity. This analysis spans from the aftermath of the First World War to the second half of the 1950s. That part of the short 20th century was characterized by important turning points, the First and Second World War, the League against Imperialism, the Pan-African Congresses, which consolidated the awareness of a common experience of racial oppression and exploitation shared by colonial peoples and the African diaspora. The analysis is focused on editorial and associations circuits, and movements, such as the Pan-African Congresses (1919-1945), the “New Negro” movement, the Garveyite movement, Black trade unionism, and African liberation movements, in particular the Positive Action in Ghana, the Zikist movement in Nigeria, and the Defiance Campaign in South Africa. In this complex framework of hierarchies and idiosyncrasies, differences and similarities in the use of Gandhi as a political trope will be highlighted, and connected with different perspectives, or visions of solidarity
Development of a porcine lactation model for the evaluation of mammary transfer of exogenous molecules - A contribution from the conception project
Get PDFAround 5 million women give birth each year in Europe and, while breastfeeding, the majority of them may need to take medications, either occasionally or continuously. Unfortunately, there is often scarce evidence of trustworthy information about how a specific molecule might affect the physiology of lactation. This is the reason that brought a European public-private partnership to fund the development of a reliable platform to provide women and health-care professionals a helpful instrument to reduce uncertainty about the effects of medication used during breastfeeding. On April 1st 2019, the ConcePTION project (Grant Agreement n°821520) started to develop such envisaged platform. The 3rd Work Package was in charge of the validation of in vitro, in vivo and in silico lactation models. Between the numerous species currently used in preclinical studies, pigs’ similarities with humans’ anatomy, physiology and genomics make them extremely useful as translational models, when proper veterinary expertise is applied. The ASA team from the University of Bologna, went first to characterize the translational lactation model using the swine species, chosen upon literature review.
The aim of this work was to lay the foundations of a porcine lactation model that could be suitable for application within pharmaceutical tests, to study drug transfer through milk prior approval and commercialization. The obtained results highlighted both strengths and critical points of the study design, allowing a significant improvement in the knowledge of pharmacokinetic physiology in lactating mammals. Lastly, this project allowed the assessment of microbial changes in gut resident bacteria of newborns through an innovative in vitro colonic model. Indeed, even if there were no evident adverse effects determined by drug residues in milk, possible alterations in the delicate microbial ecology of newborns’ gastrointestinal tract was considered pivotal, giving its possible impact on the individual health and growth
"Lesion journey" in hidradenitis suppurativa: clinical and ultrasonographic correlations
Get PDFIntroduzione:
L'idrosadenite suppurativa (HS) è una malattia immuno-mediata che colpisce i follicoli piliferi situati principalmente nelle aree ricche di ghiandole apocrine.
Materiali e metodi:
È stato condotto uno studio osservazionale prospettico monocentrico finalizzato a correlare i parametri clinici ed ecografici con: l'evoluzione delle lesioni, la probabilità di riacutizzazione o di andare incontro ad un trattamento chirurgico/laser-CO2.
Risultati:
Sono stati reclutati sessantuno pazienti con un'età media pari a 29,5 ± 7,5 anni che presentavano un numero basale di 127 noduli infiammatori, 43 ascessi e 62 fistole.
Dopo un tempo medio di 77,9 settimane, rispettivamente il 40%, 14%, 8% di noduli, ascessi e fistole erano guariti, il 5%, 30%, 29% persistevano privi di infiammazione, il 47%, 33%, 63 % presentava uno stato infiammatorio, e l'8% e il 23% dei noduli e degli ascessi erano evoluti in fistole. Sono stati registrati 137 episodi di flare nelle lesioni acute (noduli + ascessi) e 54 nelle lesioni croniche (fistole), mentre il numero di interventi procedurali è stato rispettivamente pari a 59 e 50.
I fattori predittivi associati ad un'evoluzione sfavorevole (stato infiammatorio o cronicizzazione) per ascessi e noduli sono stati: evidenza ecografica di frammenti piliferi intralesionali, elevato segnale Power Doppler (PD) ed edema all'ecografia, profondità della localizzazione ed interessamento genitale; i predittori associati alle fistole sono stati: profondità della localizzazione, edema e dimensioni della lesione.
La probabilità che una lesione acuta venisse sottoposta ad un intervento procedurale è stata correlata a: età, presenza di frammenti piliferi, segnale PD, edema e profondità della localizzazione; per le fistole l'unico predittore indipendente è stato la dimensione.
I predittori di riacutizzazione della patologia per ascessi e noduli sono stati: giovane età all'esordio, segnale PD, evidenza ecografica di frammenti follicolari, profondità della localizzazione e dimensioni; per le fistole i predittori sono stati: localizzazione ascellare, profondità della localizzazione, edema e dimensione.Background:
Hidradenitis suppurativa (HS) is an immune-mediated disorder affecting hair follicles mainly located in the apocrine gland-bearing area. It presents suppurative lesions consisting of nodules, abscesses, and fistulas that exhibit a variable degree of inflammatory activity.
Materials and Methods:
A prospective, single-center observational study was designed to correlate clinical and ultrasonographic parameters with the "lesions' evolution" at the end of the study, the probability of flaring or undergoing a surgical/CO2-laser intervention.
Results:
Sixty-one patients (25 males and 36 females) with a mean age of 29.5±7.5 years who had a total baseline number of 127 inflammatory nodules, 43 abscesses, and 62 fistulas were recruited.
After a mean follow-up time of 77.9 weeks, 40%, 14%, 8% of nodules, abscesses, and fistulas respectively had healed, 5%, 30%, 29% were free of inflammation, 47%, 33%, 63% had an inflammatory status, and 8% and 23% of nodules and abscesses had evolved into fistulas. There were 137 flare episodes in the acute lesions (nodules + abscesses) and 54 in the chronic lesions (fistulas), while the number of procedural interventions was 59 and 50, respectively.
The predictive factors associated with an unfavorable evolution (inflammatory status or chronicity) for abscesses and nodules were: presence of hair tracts, high degree of Power Doppler (PD) and edema on ultrasonography, depth of localization and genital body area; for fistulas the predictors were: depth of localization, edema, and size.
The probability of an acute lesion going to procedural intervention correlated with: age, presence of hair tracts, high degree of PD, edema, and depth of localization; for fistulas the only independent predictor was size.
The predictors of flare for abscesses and nodules were: young age at disease onset, PD signal, hair tracts, depth of localization, and size; in the case of fistulas the predictors were: axillary localization, depth of localization, edema, and size
High performance battery chargers for full electric and hybrid cars
Get PDFThis Doctoral Thesis aims to study and develop advanced and high-efficient battery chargers for full electric and plug-in electric cars. The document is strictly industry-oriented and relies on automotive standards and regulations. In the first part a general overview about wireless power transfer battery chargers (WPTBCs) and a deep investigation about international standards are carried out. Then, due to the highly increasing attention given to WPTBCs by the automotive industry and considering the need of minimizing weight, size and number of components this work focuses on those architectures that realize a single stage for on-board power conversion avoiding the implementation of the DC/DC converter upstream the battery. Based on the results of the state-of-the-art, the following sections focus on two stages of the architecture: the resonant tank and the primary DC/AC inverter. To reach the maximum transfer efficiency while minimizing weight and size of the vehicle assembly a coordinated system level design procedure for resonant tank along with an innovative control algorithm for the DC/AC primary inverter is proposed. The presented solutions are generalized and adapted for the best trade-off topologies of compensation networks: Series-Series and Series-Parallel. To assess the effectiveness of the above-mentioned objectives, validation and testing are performed through a simulation environment, while experimental test benches are carried out by the collaboration of Delft University of Technology (TU Delft)
Exploring the potential of self‐assembling nanoparticles in displaying structurally defined antigens for vaccines development
Get PDFTo meet the growing need for medical interventions against infectious diseases, several vaccines containing isolated and highly purified antigenic proteins have been developed. Compared to traditional vaccines, they are safer but show a lower immunogenicity. To overcome the latter, the use of nanoparticles for the display of target antigens is a promising strategy [1]. Virus-like particles (VLPs) and protein nanoparticles (NPs), thanks to their repetitive and highly ordered structure, can present multiple copies of the target antigens allowing the potential induction of a potent B- and T-cell response [2].
This work is focused on (i) identification of NPs prone to genetic fusion to display protein antigen, (ii) development of a strategy for the epitope display and (iii) design and development of a polyvalent NP. Different NPs and VLPs were genetically fused to a meningococcal antigen. The Domain 3 of Group B Streptococcus pilus protein has been engineered with foreign epitopes allowing the display on a NP surface. Combining structural and computational biology each chimeric molecule has been designed and its 3D has been predicted. Computationally designed molecules were produced in Escherichia coli and biochemically and structurally characterized. By combining genetic fusion and chemical conjugation approaches, a polyvalent NP has been developed displaying simultaneously two different streptococcal antigens
Results obtained show that particles can maintain their 3D structure when genetically fused with a foreign protein and they are able to correctly display the target antigen. The use of D3 allowed the identification of most immunogenic epitopes from unsoluble membrane antigens and their display on mI3 surface. Moreover, the in vivo study conducted with the polyvalent NP revealed that the use of the NP as scaffold increased the immunogenicity of both streptococcal antigens.
In conclusion, this work represents a template strategy for the development of new effective NP-based vaccines against bacterial pathogen
Il silenzio dopo le bombe. Pratica, ruolo e formazione degli interpreti nelle zone di conflitto. Un caso di studio delle guerre in Bosnia-Herzegovina e Croazia.
Get PDFThis dissertation investigates the role, training and practice of the interpreters that worked during the wars in Bosnia and Herzegovina and Croatia in the 1990s, both at a high political level and on the ground for peackeeping troops. Adopting a historical method that uses interviews, newspaper articles, videos, archival documents and pictures the author tries to retrace how those interpreters were hired, employed and what challenges they faced in their daily work. The aim is to give voice to a category that has long been forgotten, to investigate how mediated interaction is shaped by violent conflict and to offer hindsight to improve the recruitment and management of local interpreters by armed forces.Questo lavoro si concentra sul ruolo, la formazione e la pratica d'uso degli interpreti durante le guerre in Bosnia-Erzegovina e Croazia negli anni Novanta, sia ad alto livello, che sul campo per le missioni di pace. Adottando un metodo storico che si avvale di interviste, articoli di giornale, video, documenti d'archivio e fotografie, l'autrice cerca di ricostruire come questi interpreti sono stati assunti, impiegati e quali sfide hanno dovuto affrontare nel loro lavoro quotidiano. L'obiettivo è quello di dare voce a una categoria a lungo dimenticata, di capire come l'interazione mediata sia plasmata dal conflitto violento e di migliorare il reclutamento e la gestione degli interpreti locali da parte delle forze armate
Les collections de moulages d'art antique en France et en Italie (années 1870-années 1980): histoire de l'archéologie et de son enseignement
Get PDFStudiare la storia delle collezioni di calchi di arte antica, in Francia e in Italia, significa ripercorrere una parte della storia dell’archeologia di questi due paesi. Una storia di oggetti, di attori, ma anche dei progressi della scienza archeologica nello studio delle sculture greco-romane. Il punto di partenza sarà la constatazione in base alla quale la creazione di queste collezioni, a cavallo del XIX e del XX secolo, non è altro che un «transfert culturale». Attraverso l’introduzione della gipsoteca, la Francia e l’Italia non fanno che adottare e adattare il modello tedesco di insegnamento dell’archeologia. Pertanto il calco di arte antica può considerarsi un «oggetto culturale» poiché svolge il ruolo di strumento didattico, a vocazione scientifica, proprio della «cultura universitaria» tedesca. Questo transfert segna la nascita dell’archeologia come scienza e s’inserisce nel quadro più ampio di una modifica dell’insegnamento superiore e di una (ri)costruzione della nazione. Quest’ultimo processo si fonda su un altro meccanismo culturale generato dalla mondializzazione-globalizzazione, l’«invenzione della tradizione». Degli esempi sono dati da miti, come quello «della Grecia bianca» e «della Romanità» che, alimentati, loro malgrado, dai calchi dall’antico, mostrano i limiti di questi strumenti didattico-scientifici. Limiti che giustificherebbero il loro declino cominciato dopo la seconda guerra mondiale. Simboli infatti di un’archeologia intesa esclusivamente come storia dell’arte antica, strumenti appartenenti a un metodo di studio e di ricerca ormai superato, i calchi d’arte antica sono stati relegati nei magazzini universitari o hanno persino subito atti vandalici che, soprattutto negli anni Sessanta del XX secolo, assumevano un significato di contestazione politico-culturale. Tuttavia, a partire dagli anni 1980 queste collezioni sono state ‘riscoperte’ dagli studiosi, come attestano i primi convegni.Focusing on the history of plaster cast collections of ancient art, in France and Italy, means retracing a part of the history of archaeology in these two countries. A history of objects, of actors, as well of the progress of archaeological science in the study of Greek-Roman sculpture. The starting point will be the observation that the creation of plaster cast collections of ancient art, at the turn of the 19th and 20th centuries, is nothing more than a "cultural transfer". In fact, through the introduction of the cast gallery, France and Italy are merely adopting and adapting the German model of teaching of the archaeology, or rather, the "archaeology of art". Therefore, the cast of ancient art can be considered a "cultural object" in the sense that it plays the role of a teaching tool, with a scientific vocation, peculiar to German "university culture". This transfer marks the birth of archaeology as a science, it is aligned to a specific change in higher education and it allows a nation (re)building. Moreover, the consolidating nation process is based on another cultural mechanism generated by globalization, i.e. the "inventing tradition". Examples are given by myths, such as that of "white Greece" and "Romanity," which supported indirectly by casts from the ancient, show the limits of these didactic-scientific tools. Limits that would justify their decline which began after World War II. As symbols in fact of an archaeology understood exclusively as history of ancient art, as tools belonging to an outdated method of study and research, casts of ancient art were relegated to university storerooms or even suffered vandalism that, especially in the 1960s, took on the meaning of political and cultural contestation. However, since the 1980s these collections have been 'rediscovered' by scholars, as the first conferences attest.Se pencher sur l’histoire des collections des moulages d’art antique, en France et en Italie, signifie retracer un pan de l’histoire de l’archéologie de ces deux pays. Une histoire d’objets, d’acteurs, mais également des progrès de la science archéologique dans l’étude des sculptures gréco-romaines. Le constat de départ est que la création de ces collections, au tournant des XIXe et XXe siècles, n’est autre qu’un « transfert culturel » : par l’introduction de la gypsothèque, la France et l’Italie ne font qu’adopter et adapter le modèle allemand d’enseignement de l’archéologie. Par conséquent, l’on considère le moulage au même titre qu’un « objet culturel », au sens où il joue le rôle d’instrument didactique, à vocation scientifique, appartenant à la « culture universitaire » allemande. Cet emprunt témoigne de l’émergence de l’archéologie en tant que science et il s’insère dans le cadre plus vaste d’une modification de l’enseignement supérieur et d’une (re)construction de la nation. Cependant, ce dernier processus se fonde sur un autre mécanisme culturel engendré par la mondialisation globalisation, l’« invention de la tradition ». Tels sont les cas du « mythe de la Grèce blanche » ou de celui de la « Romanité » dont les moulages d’antiques deviennent les vecteurs et qui constituent en même temps leurs limites, qui ont été à l’origine même de leur déclin, commencé après la seconde guerre mondiale. Symboles d’une archéologie interprétée exclusivement comme histoire de l’art antique, instruments propres d’une méthode d’étude et de recherche désormais dépassée, les moulages ont été relégués dans les caves des universités, voire fait l’objet de vandalisme, ce qui, notamment dans les années 1960, prenait une signification de contestation politico-culturelle. Cependant, à partir des années 1980, ces collections ont été « redécouvertes » par les chercheurs, comme l’attestent les premiers colloques qui leur ont été consacrés