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Analysis of Energy-Transport Models for semiconductors
No full textIn this thesis we study the energy transport models of the charge carriers in the semiconductors, in the unipolar and one-dimensional case. These are macroscopic models, that are useful to describe the thermal eff ects in the semiconductor devices. Usually the set of equations are given by the balance equations for density and energy of the charge carriers, coupled to the Poisson equation for the electric potential. Two
energy transport models, with and without crystal heating, are presented with diff erent approaches. The fi rst energy transport model is the Chen model, in which the temperature lattice is assumed constant. We fi nd some particular solutions and we discuss them behavior depending on physical parameters, as example for the silicon. The second energy transport model includes as variable the lattice temperature. A symmetry analysis approach to this model is performed. We determine the group classi cation of the model equations, collecting them into equivalence classes and fi nd the functional forms of the constitutive functions appearing in the
equations. In some cases the reduced system solutions are found
Laparoscopic Living donor nephrectomy. Transperitoneal and Retroperitoneal Technique. Safety and efficacy
No full textIntroduction: Kidney transplantation is considered the best replacement treatment for patient with end stage renal failure but the transplant community has to face the constant shortage of organs. For this reason programs have been developed to implement the transplants from living donors, that have been shown to have the best outcomes.
The laparoscopic technique for kidney donation has almost completely supersede the open surgery being associated with short convalescence time and increased quality of life for the donor and equally effective results for the recipient. Within the different type of laparoscopic techniques the hand assisted one is at the moment the most utilised in UK. The retroperitoneoscopic techniques has been developed to try to minimise further more the potential complications of this type of surgery offering the intrinsic advantages of the conventional transperitoneal approach and potentially lower risk of intraperitoneal complications. Materials and Methods: At the Royal London Hospital in the period between July 2011 and July 2013 ninety-two Laparoscopic Hand Assisted Donor Nephrectomy (LHADN) have been performed of which 34 with retroperitoneal approach. Statistical Analysis: The data analysed were: Warm Ischemia Time (WIT), Length of operative time, Length of postoperative stay, Safety and incidence of complications in the donor. The aim of the study was to demonstrate the safety and efficacy of this technique and to compare the retroperitoneal approach with the transperitoneal hand assisted donor nephrectomy. Results: There were no significant differences within the two groups on the base of age and gender. In the retroperitoneal group the number of right nephrectomies was significantly higher (Side L/R (%) TP 55/3 - 94.8%/5.2% - RP 25/9 - 73.5%/26.5%). HARLDN was effectively and safely completed in 92 donors (100%). No conversion to open surgery was required, no intra or perioperative death was recorded. The skin to skin time despite numerically inferior in the retroperitoneal group (75 to 132 mins - median 102) was not significantly different from the operative time in the transperitoneal group (94 - 170 mins - median 114). The warm ischemia time (WIT), was identical in the two groups (median 97 sec TP vs. 96 sec RP). Length of stay (3 days) was identical in the two groups of patients while the major complication rate such us incisional hernia, bowel injury or intestinal obstruction (15% vs. 0%) was significantly higher in the transperitoneal group.
The incidence of minor complications such as urinary tract infections, pulmonary infections or wound infections was identical in the two group. Discussion: In our experience we felt that the direct approach to the renal hilum and to the vascular structures of the kidney, allowed by the retroperitoneal access, can be a potential advantage in case of complex vascular anatomy. The retroperitoneal technique may be considered the elective approach for patients with previous abdominal surgery, since it allow to operate in a space surgically virgin avoiding long and potentially dangerous dissection of the intraabdominal adhesions. With the retroperitoneoscopic technique the access to the hilum and the vessels is more direct and the mobilization of the intraperitoneal organs is not needed, possibly leading to fewer incidences of postoperative ileus and damage to these organs. The downside of the technique is represented by the limited working space and the presence of few anatomical landmarks. Conclusions: the retroperitoneal laparoscopic live donor nephrectomy offers all the advantages of the laparoscopic approach plus an intrinsic advantage of the potentially lower risk for early and late donor intraperitoneal complications and can be electively used in patients with previous abdominal surgery avoiding potentially dangerous dissection of adhesions
Athens in Petros Markaris. Landscape and urban identity of a Greek city in 20th -21st century fiction
No full textIn questo lavoro cercheremo di esaminare da una parte, lo sviluppo urbanistico, storico e sociale di Atene, eletta a capitale della Grecia postunitaria (1834), e, dall altra, l immagine e il ruolo della città nel romanzo poliziesco attraverso le opere dell autore contemporaneo greco Petros Màrkaris.
La città di Atene è caratterizzata da un particolare sviluppo urbano, poiché in soli due secoli (XIX-XXI) riesce a trasformarsi da un villaggio di 4.000 abitanti in una città che rappresenta un perfetto esempio di gigantismo urbano, collocandosi fra le poche città al mondo che oltrepassano la soglia dei tre milioni di abitanti. Piani regolatori e pagine di una letteratura cittadina , qual è prevalentemente il giallo, si intersecano tra loro. Se i primi intendono regolare lo spazio urbano, il secondo si pone l obiettivo di interpretarlo. Infatti, il romanzo poliziesco nasce dalla necessità degli autori di raccontare la realtà delle grandi città che costituiscono lo spazio naturale, biologico , dove cresce e si sviluppa la criminalità.
Atene, da vera metropoli multi-etnica dalle mille realtà diverse, dotata di un identità culturale e un paesaggio urbano che oscillano tra Oriente e Occidente, offre lo spazio ideale per l ambientazione di un romanzo poliziesco, o meglio, un romanzo sociale con trama poliziesca, come viene spesso definito il noir di Petros Màrkaris, e diventa la sua protagonista insieme con il commissario Kostas Charitos.Oggetto principale del racconto costituiscono le conseguenze del suo mastodontico urbanesimo, quali il traffico metropolitano, e l ambiente inquinato del centro, ma soprattutto le storie racchiuse nei vari quartieri di ogni estrazione sociale
Identità culturale e diritto penale. Riflessioni sul reato culturalmente motivato
No full textOggetto della trattazione e' la disamina delle soluzioni dottrinarie e giurisprudenziali piu'significative e stimolanti nel dibattito aperto sul reato culturalmente motivato. Il punto di partenza e' l'affermazione del ruolo della cultura nella vita degli individui. L'istituto della cultural defense e' individuato come strumento potenzialmente atto a garantire il diritto alla cultura, il diritto alla liberta'di religione e coscienza, il principio di uguaglianza, nei limiti del rispetto dei diritti umani tutelati dalle norme di diritto internazionale
Physiological and productive responses of Miscanthus genotypes to different climatic constraints in Mediterranean environment
No full textStrong global growth and development has increased demand for energy to refine, manufacture and transport products to support the lifestyles of an increasingly developing and globalized world. In recent decades, fossil fuels have become important sources of energy. However, with increasing demand, there has been developing concern over the sustainability of fossil fuels relating to their potential future sources and harmful byproducts of use, specifically large net carbon releases, which has spurred interest towards the use of alternative renewable energy sources. Potential alternatives are available including wind, solar, hydro, and biomass, all of which are touted to have greater environmental benefits relative to fossil fuels. There has been increasing interest in the use of perennial grasses as energy crops in the US and Europe since the mid-1980s. The characteristics which make perennial grasses attractive for biomass production are their high yield potential, the high contents of lignin and cellulose of their biomass and their generally anticipated positive environmental impact. For this purpose, three different researches were carried out with the aim of studying i) the adaptation and biomass production potential of 18 Miscanthus accessions, representing 5 Miscanthus species, collected from a wide geographical range (Numata, 1974) for suitability to semi-arid Mediterranean climates; ii) the effect of harvest time (autumn and winter time) on biomass yield, morph-biometric characters, moisture content, cellulose, hemicelluloses and lignin contents for second generation bioethanol production and ash content for combustion purposes in a long term plantation of Miscanthus x giganteus in a Mediterranean environment; iii) the effect of heat stress, in controlled-environment, on 5 Miscanthus genotypes, coming from the Miscanthus germplasm collection at Institute of Biological, Environmental and Rural Sciences (IBERS) of the Aberystwyth University Wales UK, to identify if the high temperature have a negative effect on the growth, partitioning and physiology of Miscanthus plants. Results suggest that some Miscanthus accessions are suitably adapted to maintain high biomass in a semi-arid Mediterranean environment and that the most commonly available commercial Miscanthus genotypes (M. x giganteus and Goliath) are not well adapted to the Mediterranean climate or environments where water is a limiting factor, and there are other Miscanthus accessions that produce high biomass in water limited semi-arid regions. Long term Miscanthus plantations strictly depend by the thermopluviometric trend of the growing season, decreasing biomass yield as rainfall reduces and the biomass for specific end uses presents higher quality (in terms of more hemicellulose and cellulose content than ash content), with winter harvest. Relative to low temperature, high temperature decreased the plant height (~48%), above-ground dry biomass (~66%), below-ground dry biomass (~26%) and photosynthetic response to absorbed light (~13%). The most widely available and commonly used variety of Miscanthus is sensitive to high temperatures and there are other genotypes that have a higher capacity for carbon assimilation in high temperature environments
Identification and functional analysis of genes associated with oncogenesis
No full textA RMD, mapping at the 6q26-27 region, which harbored a locus of senescence SEN6 was also implicated with tumorigenesis. One cDNA clone mapped within the RMD was recovered, it was a putative novel gene that encodes a protein without any homology with known sequences, named CATP (Cytomembrane-Associated Trafficking Protein). Modifications of its sequence across evolution, especially in Great Apes, were evaluated. Mutational analysis allowed to identify different alleles of the gene. Alleles were analyzed for association with some human pathologies. Functional analysis was performed in S. cerevisiae model, in order to clarify function of catp and the different effects of its alleles on yeast chronological lifespan. catp alleles affect yeast growth in distinguishable ways, moreover they showed different sensitivity to oxidative stress. So far a possible role of catp in senescence and/or tumorogenesis, throught ossidative stress responce and ROS level regulation, has been suggested
IL MINISTERO DEGLI AFFARI ESTERI E L AMMINISTRAZIONE ITALIANA, 1947-1953.
No full textQual è stato, dunque, il ruolo dell amministrazione italiana, in particolare del ministero degli Affari Esteri e della diplomazia italiana nella costruzione europea? Per quanto riguarda i fatti propulsivi e tecnici del processo d integrazione, ad esempio la gestione degli aiuti americani derivanti dal Piano Marshall, sebbene essa fosse imperniata principalmente sul comitato CIR-ERP, suggerisce Ruggero Ranieri , non portò ad un esautoramento del MAE poiché troppo importanti erano le sue competenze internazionali e troppo alta la qualità di alcuni suoi ambasciatori e funzionari. Di sicuro il suo ruolo, in passato predominante ed esclusivo in materia di politica estera era stato esposto molto più da vicino alla competizione dei ministeri economici. Si può dire che, in linea generale il mercato comune europeo abbia ristretto il campo di competenza del ministero degli esteri a favore di quelli economici tuttavia sul piano negoziale il ministero degli esteri avvalendosi della collaborazione di preziosi diplomatici ha impresso un importante spinta verso l integrazione europea tra il 1947 e il 1953
Infomobilità applicata ai sistemi di trasporto a domanda flessibile
No full textIl settore di produzione di beni e servizi è sempre alla continua ricerca di sistemi che possano ottimizzare i loro processi di produzione, con l obiettivo primario di ridurre i costi sostenuti. La crisi economica, che negli ultimi anni ha colpito l Europa in molti settori economico-produttivi, ha accentuato ulteriormente l esigenza di ricercare tutte quelle procedure e/o metodologie che possano permettere un abbattimento delle spese, mantenendo gli stessi standard qualitativi e quantitativi.
Tra i settori maggiormente in crisi, soprattutto nelle regioni meridionali d Italia, c è quello della gestione integrata dei rifiuti solidi urbani.
I problemi tipici che si riscontrano in questo campo possono essere inglobati in due macro-categorie:
-la raccolta dei rifiuti su scala territoriale locale, che ha come obiettivo principale quello di ottimizzare il servizio al fine di minimizzare i costi di trasporto all interno dei centri urbani;
- il trasporto dei rifiuti su scala territoriale regionale, dai centri di produzione locali agli impianti di trattamento/recupero/smaltimento quello su scala regionale, che, oltre ad avere come obiettivo quello di minimizzare i costi di trasporto, ha lo scopo di localizzare ed individuare i siti ottimali per la realizzazione di nuovi impianti di trattamento e smaltimento dei rifiuti.
Il problema del trasporto dei rifiuti solidi urbani dai luoghi di produzione (città) ai luoghi di smaltimento (impianti di trattamento) è una fase del sistema di gestione solitamente trascurata. Questo perché, a torto, considerata poco impattante rispetto alle altre fasi di trattamento. Il presente lavoro, invece, ritenuta l importanza del problema, si propone di determinare i flussi e i costi del trasporto di rifiuti all interno di un territorio ed in più di dimostrare come una corretta gestione del conferimento del rifiuto nei vari impianti di trattamento/recupero/smaltimento, possa contribuire in modo significativo al miglioramento del processo di gestione dei rifiuti e ad un concreto risparmio di risorse economiche ed ambientali.
Un notevole contributo in tal senso è dato dai cosiddetti Sistemi di Trasporto Intelligenti (Intelligent Transportation System, ITS), che grazie a tecnologie telematiche innovative (Information and Communication Technologies, ICT) permette di offrire un servizio flessibile ad una domanda anch essa flessibile a causa della variabilità giornaliera della produzione di rifiuti solidi urbani, nonché a tutta una serie di problematiche e criticità dovute a fattori non prevedibili.
Alla luce dei risultati emersi dallo studio, sia su scala territoriale urbana che su scala territoriale regionale, si può concludere che una corretta pianificazione dei sistemi di gestione dei rifiuti dovrebbe prevedere un analisi dettagliata della fase di raccolta e trasporto dei rifiuti e prevedere la valutazione di possibili alternative per la diminuzione delle emissioni totali attraverso l ottimizzazione dei trasporti.
A tale scopo l integrazione di tecnologie telematiche innovative e l utilizzo di modelli di ottimizzazione dei percorsi di raccolta nonché dei flussi dei rifiuti dai centri di produzione agli impianti di smaltimento, può essere determinante per il raggiungimento di un efficiente gestione integrata dei rifiuti solidi urbani
Physiological and molecular mechanisms of seed germination in weed species
No full textSeed dormancy provides a mechanism for plants to delay germination until conditions are optimal for survival of the next generation. Knowledge of dormancy release and dormancy induction requirements is important to increase our understanding about the entire process. Furthermore, to assess the association between gene expression patterns and physiological phase in dormancy is a major goal to allow a positive definition of this condition.
In Chrysanthemum coronarium var. concolor and var. discolor, anatomical and germination analyses showed that non-deep physiological dormancy (PD) is the more plausible type of dormancy for both of them. The genetic composition of Chrysanthemum coronarium varieties was characterized using Inter Simple Sequence Repeat (ISSR) PCR together with a DNA-Barcoding approach.
Seed priming treatments were used in a non-dormant species, Leucanthemum vulgare, to induct secondary dormancy at specific temperature range and a long-priming treatment was used for its release. Fluridone and giberellic acid were tested to investigate the metabolic pathway involved in the onset of secondary dormancy and in its maintenance.
Five probable housekeeping genes, useful as reference genes for quantitative PCR (qPCR) analysis in seed tissue, were identified in Chrysanthemum coronarium and in Leucanthemum vulgare, isolated and confirmed with comparative analysis with homologous genes in model species. One radicle-protrusion associated gene, EXP (Expansin), was identified in the two species, isolated and confirmed. Three dormancy-associated genes, DOG1 (Delay Of Germination 1), FLC (Flowering Locus C), HUB2 (Histone Mono-Ubiquitination 2) were identified in Chrysanthemum coronarium and in Leucanthemum vulgare
Assembly and characterization of molecular films for energetics and electronics.
No full textThis thesis was focused on the preparation and on the characterization, of functional thin films for molecular electronics and energetics.
In the first part of this work a nanoscale electrical investigation of molecular wires was discussed. Molecular wires were prepared as a self assembled array on gold by means of a bottom up approach that exploits the coordination of metal with terpyridine-based ligands. These molecular wires were characterized by using different techniques. The formation and growth of the molecular films has been demonstrated by ToF-SIMS, XPS and UV-Vis spectroscopy. Structural information was obtained from NEXAFS measurements, that demonstrated that wires grow vertically to the surface and that the orientation doesn t change during the growth. The electrical characterization was performed by using the conductive atomic force microscopy (C-AFM) technique, that allowed to determine the molecular conduction mechanisms of these systems.
The second part of the work was focused on the development of methodologies for functionalization of oxide substrates, suitable for applications in the field of dye sensitized solar cells. The ZP methodology has been applied, and the amount of surface coverage as well as the stability of the formed layers has been studied by using a phosphonate derivative of rhodamine B. Then the ZP method was applied to the preparation of different systems of interest in solar energy conversion, including a self assembled bilayer on TiO2 made out a dendrimeric complex of Ru (II) (the sensitizer) and a polyoxometallate (the catalyst) that can act as an electrode for photo -induced water splitting.
Finally, the general problem of obtaining molecular depth profiling of organic materials has been discussed. In particular, a SIMS method (NO-assisted cluster-SIMS) has been studied, that gives promising results in this direction. With the aim of studying the applicability of the method to polymer-based multilayers, well-controlled layered systems have been prepared by means of layer-by-layer polyelectrolyte deposition. C60-SIMS depth profiling of these systems highlighted the possibility of obtaining a good profile depends heavily on the order in which layers with different radiochemical behavior are deposited. The cluster-SIMS technique was applied to the study of a system of interest in molecular electronics. In particular the measured C60-SIMS profiles provided evidence of in-depth inhomogeneous distribution of oligothiophenes in binary blends formed by oligomers with different molecular weight