118 research outputs found
Reflections on an interview with the late Prof Maria Antonia Modolo = Considerazioni su di un'intervista alla Prof Maria Antonia Modolo, recentemente scomparsa
No full textL’Autrice, ora Assistente di Ricerca presso il Dipartimento di Sanità Pubblica dell’Università degli Studi di Milano, Italia, nel periodo in cui è stata Residente presso
la Scuola di Sanità Pubblica dell’Università degli Studi di Perugia, ha avuto occasione di intervistare la Prof.ssa Maria Antonietta Modolo, una delle più significative
pioniere dell’Educazione alla Salute e della Promozione della Salute sia in Europa che in questo Paese, e suo mentore in quel momento. La Prof Modolo, recentemente scomparsa, in quell’occasione ha spiegato in dettaglio tutti gli obiettivi di queste discipline e l’impatto che possono avere sulla vita della popolazione dei paesi
sviluppati e in via di sviluppo, se applicate all’interno di un solido quadro di salute pubblica.The Author, now a Research Assistant at the Department of Public Health of the University of Milan, Italy, in the period she was a Resident of the School of Public Health of the University of Perugia, had the occasion to interview Prof Maria Antonietta Modolo, one of the most significant pioneers of Health Education and Health Promotion both in Europe and in this Country, and her mentor at that time. Prof Modolo, who recently passed away, in that occasion explained in detail all the goals of these disciplines, and the impact they can show on the life of the population of developed and developing countries, if applied within a robust public health framework
Dal clivus Scauri al vicus Capitis Africae: gli affreschi della vigna Guglielmina a Roma nei disegni dei Bartoli
No full textTwo frescoed room discovered on the Caelian hill during the seventeenth century and reproduced by Pietro Santi Bartoli in four drawings were published by the Comte de Caylus in his Recueil de peintures antiques (Paris, 1757). Their findspot has since been situated in the vineyard of Stefano Guglielmini (also known as the “vigna Guglielmina”), located by Lanciani on the Clivo di Scauro facing the church of SS. Giovanni e Paolo. The first room (plates XXIII, XXIV and XXV of the Recueil), discovered in 1639, became famous in art–historical studies due to the presence of portraits of a Roman family on the vaulted ceiling and due to the controversial interpretation of two lunettes with marine iconography; the second room (plate XXVI in the Recueil), less well known, is decorated with a fresco of three mythological figures, each placed in a rectangular panel.
Following archival research, the author has been able critically to re–examine both the topographical context of the find and the composition of the frescoes. This has led him to reject the traditional conclusions, hitherto conditioned by a misinterpretation of the Recueil made by the antiquary Ridolfino Venuti in the mid–eighteenth century. In the first place, the author has revised the location of Stefano Guglielmini’s vineyard: it should be situated, in his view, not on the Clivo di Scauro but on the road that ascended from the Colosseum to the Navicella. This finding then led in turn to a different topographical distribution of the frescoes: while those of the first room are to be located within the vineyard of S. Gregorio al Celio, the second fresco should be placed in the vigna Guglielmina proper. The identification of four other drawings of Bartoli based on Roman frescoes in the vigna Guglielmina in the collections of RIBA in London and Holkham Hall in Norfolk has permitted the author to understand that this latter fresco was not isolated, but must have formed part of a larger cycle that decorated the interior of a triple–apse room, probably the triclinium of a rich late–antique domus overlooking the ancient vicus Capitis Africa
Distributed Trap Levels and Hot-Electron Trapping in Power GaN HEMTs Characterization and Modeling
No full textGallium Nitride (GaN)-based high electron mobility transistors (HEMTs) are rapidly emerging as front-runners in high-power mm-wave circuit applications. Possible targets that would benefit of the advantages of GaN–based devices include efficient power supplies, DC/DC converters and AC/DC adapters, as well as the field of radars and telecommunications.
Despite the recent commercial success of GaN-based devices, internal physical mechanisms are often not completely understood and still constitute a challenge to the development of a mature GaN-based technology. Besides the difficulties of growing a high–quality GaN material, point defects at interfaces play a major role in terms of reliability.
In the present thesis, several aspect of the device instability have been investigated from both and experimental and theoretical point of view. Throughout this thesis, our goal is to build a quantitative and qualitative understanding of the main factors undermining the device stability under real application conditions.
By comparing Hard and Soft switching turn-on commutations, we demonstrated how turn-on stress plays a major role in the on-resistance degradation, while off-state bias does not have a relevant influence on device properties. Furthermore, by repeating the experiment on several devices with different L_GD, we were able to demonstrate the important role of electric field in determining the R_ON increase and to rule out a significant contribution of self-heating.
Then, in order to observe the full trapping and de-trapping kinetics of hot-electrons we focused on semi-ON stress analysis by means of a custom setup able to perform Drain Current Transient (DCT) analysis. Firstly, by focusing on the trapping phase, a physical understanding of the hot electron phenomena in GaN-based HEMTs is developed with a cross-comparison between theoretical analysis and experimental data. Linear dependency on the applied electric field and logarithmic dependency on the current density in determining the severity of current collapse are found. Results provide important information for the modeling of hot-electron trapping kinetics in GaN-based power transistors. The first 10 us of operation are critical in determining the current collapse during stress.
Secondly, by focusing on the recovery phase, we propose a general methodology for mapping the properties (activation energy, cross sections) of a distribution of surface/interface states in GaN-based electronic devices. To prove the validity and usefulness of the model, the extracted map distributions are used as input for TCAD simulations. The results obtained by TCAD closely match the experimental transient curves, thus confirming the effectiveness of the developed technique.
The theoretical knowledge built along this thesis allowed us to propose a new approach for compact modeling of the stretched exponential trapping/de-trapping kinetics of p-GaN HEMTs is proposed. Novel insight on the GaN HEMT dynamic performance degradation is given highlighting how the criticality of a trap is dependent on its location in the capture and emission time map. The duty cycle plays a key role in determining the performance degradation trajectory, while the frequency is related to the amplitude of the capture and emission process per cycle.Gallium Nitride (GaN)-based high electron mobility transistors (HEMTs) are rapidly emerging as front-runners in high-power mm-wave circuit applications. Possible targets that would benefit of the advantages of GaN–based devices include efficient power supplies, DC/DC converters and AC/DC adapters, as well as the field of radars and telecommunications.
Despite the recent commercial success of GaN-based devices, internal physical mechanisms are often not completely understood and still constitute a challenge to the development of a mature GaN-based technology. Besides the difficulties of growing a high–quality GaN material, point defects at interfaces play a major role in terms of reliability.
In the present thesis, several aspect of the device instability have been investigated from both and experimental and theoretical point of view. Throughout this thesis, our goal is to build a quantitative and qualitative understanding of the main factors undermining the device stability under real application conditions.
By comparing Hard and Soft switching turn-on commutations, we demonstrated how turn-on stress plays a major role in the on-resistance degradation, while off-state bias does not have a relevant influence on device properties. Furthermore, by repeating the experiment on several devices with different L_GD, we were able to demonstrate the important role of electric field in determining the R_ON increase and to rule out a significant contribution of self-heating.
Then, in order to observe the full trapping and de-trapping kinetics of hot-electrons we focused on semi-ON stress analysis by means of a custom setup able to perform Drain Current Transient (DCT) analysis. Firstly, by focusing on the trapping phase, a physical understanding of the hot electron phenomena in GaN-based HEMTs is developed with a cross-comparison between theoretical analysis and experimental data. Linear dependency on the applied electric field and logarithmic dependency on the current density in determining the severity of current collapse are found. Results provide important information for the modeling of hot-electron trapping kinetics in GaN-based power transistors. The first 10 us of operation are critical in determining the current collapse during stress.
Secondly, by focusing on the recovery phase, we propose a general methodology for mapping the properties (activation energy, cross sections) of a distribution of surface/interface states in GaN-based electronic devices. To prove the validity and usefulness of the model, the extracted map distributions are used as input for TCAD simulations. The results obtained by TCAD closely match the experimental transient curves, thus confirming the effectiveness of the developed technique.
The theoretical knowledge built along this thesis allowed us to propose a new approach for compact modeling of the stretched exponential trapping/de-trapping kinetics of p-GaN HEMTs is proposed. Novel insight on the GaN HEMT dynamic performance degradation is given highlighting how the criticality of a trap is dependent on its location in the capture and emission time map. The duty cycle plays a key role in determining the performance degradation trajectory, while the frequency is related to the amplitude of the capture and emission process per cycle
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Influence of diluent alkyl substitution on the extraction of Am(III) and Eu(III) by a 6,6’-bis(1,2,4-triazin-3-yl)-2,2’-bipyridine ligand dissolved in alkylated cyclohexanone Diluents
No full textSeveral alkylated cyclohexanones were investigated as potential diluents for the selective extraction of Am(III) from Eu(III) from nitric acid solutions by the CyMe4-BTBP ligand. No significant extraction of either of the metal ions was observed for these diluents themselves. In the extractions from 1 M HNO3, 3-methylcyclohexanone and 4-methylcyclohexanone gave comparable results to cyclohexanone whereas in the extractions from 4 M HNO3, 2-methylcyclohexanone, 3-methylcyclohexanone and 4-methylcyclohexanone all gave superior results. For the monomethylated diluents, DAm and SFAm/Eu decreased in the order of alkyl substitution 2 > 4 ~ 3. However, alkyl substitution of cyclohexanone significantly slows down the extraction kinetics compared to cyclohexanone, and the position of alkyl substitution was found to play an important role in the solvents properties. 3-Methylcyclohexanone was identified as the most promising of the diluent
Dialectical Archive
No full textThe project deal with the urban variation of Borghehout in the city of Antwerp. It is the project of an archive with a sequence public functionsArchiveArchitecture, Urbanism and Building Science
Cumulative Hot-Electron Trapping in GaN-Based Power HEMTs Observed by an Ultra-Fast (10V/ns) on-Wafer Methodology
No full textThe goal of this paper is to advance the understanding of the impact of hard switching on the dynamic performance of GaN-based HEMTs. To this aim, we developed a fast (10 V/ns) on-wafer system for testing devices in hard switching. The system has been used to study the reliability of several WG = 2 mm p-type GaN HEMTs with different LGD or buffer properties. First, we show that by optimizing the drain node capacitance, we can speed-up the hard-switching transition to a few ns, even on-wafer level. Second, repeating the experiment by using multiple frequencies, from 1 kHz to 100 kHz, we demonstrate that, in real-world applications, cumulative turn-on stress has a much stronger effect on RON compared to off-state stress. Third, by comparing the results on identical devices having shorter LGD, we pinpoint hot electrons as the main mechanism in the device degradation, ruling out the contribution of self-heating. Finally, by comparing three wafers with different processing conditions (different passivation, different buffer) we suggest that trapping phenomena related to hot electrons happen in ns time scale and that the properties of the buffer can significantly impact the dynamic performance of the devices in hard switching
Metamorphosis of the Metamorphoses: Italian rewritings of Ovid between Renaissance and Baroque
No full textMy dissertation is the first to consider the essential nature of pre-Modern Italian vernacularizations of Ovid’s Metamorphoses, by treating them as rewritings rather than mere translations. Through this perspective, I expose the innovative drive that renders a text a separate entity from its model. Moreover, I highlight the crucial contributions that these rewritings provide to the reception of a classical masterpiece, as well as to the evolution of Renaissance and Baroque poetics. This study focuses on three volgarizzamenti: Gabriele Simeoni’s Metamorfoseo, Giovanni Andrea dell’Anguillara’s Metamorfosi, and Giovanni Palazzi’s Ovidio Istorico Politico Morale. Each text approaches Ovid’s work in a unique way, synthesizing or expanding its content, and converting the poem into prose. Each author also relates to Ovid from a different standpoint, which ranges from celebrating his legacy, to actively competing with him, to exploiting the classical author’s fame. I account for the relationships between the Latin (and French) models and their Italian interpretations through philological reading, analysis of the editorial history of the rewritings, and methods employed in comparative literature. My dissertation is also the first to utilize translation studies (in particular the cultural turn) and literary criticism (especially intertextuality, Structuralism, and Readers’ Response theory) to reveal which aspect each rewriting problematizes: the author, the addressee, or the targeted public. Furthermore, I offer a comprehensive analysis of the interplay between word and image in the aforementioned works. Whereas previous studies mainly aimed at identifying the figurative sources, I address the consequences of whether illustrations were recycled from another book or crafted purposely for that precise text. I also examine how illustrations affect the message of a work (reinforcing or undermining it), what value they hold with respect to the written counterpart, and how their positioning on the page determines their role. I thus demonstrate the importance of considering rewritings within literary studies—rather than dismissing them as secondary, derivative literature—as they allow us to track trends in poetics and understand the reception of the classics in the transitional and transformative era between the Renaissance and the Baroque
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The separation of americium(III) from europium(III) by two new 6,6'-bistriazinyl-2,2'-bipyridines in different diluents
No full textThe synthesis and extraction of americium(III) and europium(III) from aqueous nitric acid solutions by the new BTBP ligands 6,6’-bis(5,5,7,7- tetramethyl-5,7-dihydrofuro[3,4-e]-1,2,4-triazin-3-yl)-2,2’-bipyridine (Cy5-O-Me4-BTBP), and 6,6’-bis(5,5,7,7-tetramethyl-5,7-dihydrothieno[3,4-e]-1,2,4-triazin-3-yl)- 2,2’-bipyridine (Cy5-S-Me4-BTBP) is described. The affinity for Am(III) and the
selectivity for Am(III) over Eu(III) of Cy5-S-Me4-BTBP were generally higher than for Cy5-O-Me4-BTBP. For both ligands, the extraction of Am(III) and Eu(III) from 3 M HNO3 into 3 mM organic solutions varied with the diluent used. The
highest distribution ratios and separation factors observed were in cyclohexanone and 2-methylcyclohexanone, respectively. For Cy5-S-Me4-BTBP, there is a strong
correlation between the distribution ratio for Am(III) and the permittivity of the diluent used. With 1-octanol as the diluent, low distribution ratios (D(Am) < 1) were observed for Cy5-S-Me4-BTBP although this ligand extracts Am(III) selectively (SFAm/Eu = 16-46 from 1-4 M HNO3). For Cy5-S-Me4-BTBP, Am(III) is extracted as the disolvate. The distribution ratios for Am(III), and the separation
factors for Am(III) over Eu(III) are both significantly higher for CyMe4-BTBP than they are for Cy5-O-Me4-BTBP and Cy5-S-Me4-BTBP in cyclohexanone. Changing the diluent from cyclohexanone to 2-methylcyclohexanone leads to a
decrease in D(Am) but an increase in SFAm/Eu for Cy5-S-Me4-BTBP
Utilização da técnica do AgNOR em Patologia: Uma Revisão de Literatura
No full textTCC (graduação) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Odontologia.As regiões organizadoras nucleolares (NORs) são segmentos de DNA que estão localizados nos braços curtos dos cromossomos acrocêntricos humanos 13,14,15,21 e 22. As NORs transcrevem o RNA ribossômico, o qual será traduzido para proteína, formando os ribossomos, que participarão da síntese proteica. Esses segmentos de DNA são denominados AgNORs pois são marcados seletivamente pelo nitrato de prata, sendo identificados, em uma lâmina histológica, como pontos castanhos ou negros dentro das células. As NORs estão diretamente relacionadas com a atividade celular proliferativa, ou seja, quanto maior é a atividade proliferativa de uma célula, maior a quantidade de NORs encontrada. A técnica do AgNOR consiste, portanto, da ligação do nitrato de prata as NORs, e ela tem sido amplamente empregada como marcador de atividade proliferativa em processos patológicos, já que nestes a proliferação celular está aumentada em relação aos padrões considerados normais. Visto isso, o presente trabalho consiste em revisar a literatura científica para verificar a aplicabilidade da técnica de marcação pelo AgNOR nas diferentes patologias que tem manifestação buco-maxilo-facial.Nucleolar organizer regions (NORs) are segments of DNA that are located on the short arms of the human acrocentric chromosomes 13,14,15,21 and 22. NORs transcribe messenger RNA, which is translated into protein, forming the ribosomes, which participate in protein synthesis. These DNA segments are called AgNOR are selectively marked by silver nitrate, being identified in a histological slide, as black or brown spots in the cells. NORs are directly related to cell proliferative activity, ie, the higher proliferative activity of a cell, the greater the amount of NORs found. The AgNOR technique is therefore binding of silver nitrate NORs, and it has been widely used as a marker of the proliferative activity in pathological processes, since in these processes cell proliferation is increased compared to normal standards. Based on this, the present work consists in a review of the literature to evaluate the applicability of the AgNOR technique in different pathologies that have maxillo-facial manifestation
Effect of water content and load applied by the press wheel on the soil-seed environment in the soybean direct planting system
No full textO condicionamento físico do solo ao redor das sementes reveste-se de grande importância para o bom desenvolvimento inicial da cultura, assegurando uma população adequada de plantas. O adequado contato solosemente é um pré-requisito para a rápida emergência e o bom estabelecimento da cultura. O presente trabalho teve como objetivo estudar os efeitos da combinação entre teores de água do solo e cargas aplicadas pela roda compactadora da semeadora-adubadora sobre o contato solo-semente, em sistema de plantio direto na cultura da soja. Utilizou-se o esquema de parcelas subdivididas, em que as parcelas constituíram os três teores de água (U1, U2 e U3), correspondentes a 0,27, 0,31 e 0,36 kg kg-1, respectivamente, e as subparcelas, os quatro níveis de carga aplicada pela roda compactadora (C1, C2, C3 e C4), correspondentes a 0, 50, 90 e 140 N, respectivamente, no delineamento em blocos ao acaso, com quatro repetições. Antes da instalação do experimento foi realizada a caracterização física da área experimental por meio da análise granulométrica, do teor de água do solo, da densidade do solo, densidade de partículas, porosidade total e resistência mecânica do solo à penetração. Após o plantio, foram avaliados o índice de velocidade de emergência de plântulas, o diâmetro médio ponderado dos agregados na linha de semeadura, a porcentagem de finos < 2,0 mm, as densidades mínima, média e máxima do solo na região da semente, os perfis de densidade mínima, média e máxima do solo e a resistência mecânica do solo à penetração na linha de semeadura. De acordo com os resultados obtidos, pode-se concluir que: as cargas aplicadas pela roda compactadora elevaram a densidade do solo no plano vertical da linha de semeadura abaixo da profundidade de semeadura, quando comparada com os valores obtidos antes do plantio; a combinação entre cargas aplicadas pela roda compactadora e os teores de água no solo não influenciaram a porcentagem de finos < 2,0 mm e as densidades mínima, média e máxima do solo na região da semente; o maior índice de velocidade de emergência (IVE) ocorreu no teor de água igual a 0,33 kg kg-1 e na carga de 86,21 N; a utilização da tomografia computadorizada em amostras indeformadas de solo possibilitou quantificar os perfis das densidades mínima, média e máxima do solo, permitindo a caracterização das densidades desde a superfície até a profundidade analisada; a carga máxima de 140 N aplicada pela roda compactadora sobre a semente causou encrostamento superficial do solo, retardando a emergência das plântulas; e o plantio da soja não deve ser realizado sem compactação do solo sobre a semente.The soil s physical conditioning around the seeds is important to the initial cultivation development and to assure an adequate plant population. An appropriate soil-seed contact is required to a rapid emergence and a good effectiveness of cultivation. The present work aimed to study the effects of the combination between the soil water contents of the soil and the loads applied by the press wheel of seed drills on the soil-seed contact in a system of direct planting cultivated with soybean. The experiment was made as subdivided design, where units had three soil water contents (U1, U2 e U3) corresponding to 0.27, 0.31 and 0.36 kg kg-1, and in the sub-units, the four load levels applied by the press wheel (C1, C2, C3 e C4), corresponding to 0, 50, 90 and 140 N, respectively, in random blocks deign, with four repetitions. Before the experiment installation, physical attributes of the experimental area were determined: textural analysis, soil water content, soil density, particles density, total porosity and the mechanical soil resistance. After planting, the emergence speed index, the aggregate average diameter in the planted line, the percentage of fines (< 2.0 mm), the minimum, medium and maximum soil density in the seed area, the minimum, medium and maximum soil density profile, and the mechanical soil resistance to the penetration in the planted line. According to the results, the present work allowed conclude that: the loads applied by the press wheel increased the soil density in the vertical planting level beneath the planting depth, when compared with values obtained before the planting; the combination between the loads applied by the press wheel and the soil water contents did not influence the < 2.0 mm percentage and the minimum, medium and maximum soil densities in the seed area; the best plant emergence speed index occurred whit soil water contents of 0.33 kg kg-1 and loads of 86.21 N; using the computerized tomography of non-deformed soil samples, it was possible to quantify minimum, medium and maximum soil density profile, allowing the detailed densities characterization from surface down to the studied depth; the maximum load of 140 N applied by the press wheel on the seed caused a superficial crust of the soil, delaying the plants emergence; soybean planting should not occur without soil compactation around the seed.Conselho Nacional de Desenvolvimento Científico e Tecnológic
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