2,715 research outputs found
Realtà, realismo, straniamento : Auerbach e il romanzo cavalleresco fino a Cervantes
No full textAuerbach’s research, besides exploring the three main fields the author explicitly names (i.e. the succession of different and differently grounded forms of realism in literary fiction, the alternate splitting and melting of styles, the link between literary work and a Christian vision of the world), in various chapters of Mimesis, and particularly in chs. 2, 6, 12, 14 and 20, is also focused, albeit only implicitly, on the developments of a further distinctive feature in Western literature, which is the emergence of subjectivity in the representation of reality. Focusing mainly on the chapter on courtly romance (ch. 6) and on the Quijote (ch. 14), this essay will examine Auerbach’s interpreting work on texts that adopt, in different ways, a ‘subjective point of view’; this kind of interpretation is, in part, unexpectedly similar to the approach of other critics and theorists of literature contemporary to Auerbach, like Bachtin, Américo Castro and Viktor Šklovskij
Shedding light on the black hole: The roll-out of broadband access networks by private operators
No full textSeveral market studies have indicated that the roll-out of broadband has significant economic and social relevance. The investments in broadband infrastructures needed to realise these economic and social benefits are, however, high-risk. This is firstly caused by the fact that the roll-out of access networks is extremely costly and requires high initial investments. Moreover, the multidisciplinary environment and involvement of many actors with diverging objectives and interests cause high complexity. Moreover, the market for broadband is changing fast and continuously. Although broadband has been on the academic research agenda for quite some time, this has as yet not resulted in a structured insight into the decision-making process around the upgrading of broadband networks, seen from the perspective of private operators and taking into account the vast complexity of the surroundings in which this decision-making process takes place in. The objective of this research was to provide a unifying theory combining technical, economic, market-related and regulatory factors with regard to an evolutionary, flexible approach of network upgrading from a decision-maker perspective. The result of this research is a robust, explanatory, parsimonious model for the impact and outcomes of broadband roll-out. This model provides a certain degree of stability in this multidisciplinary, unpredictable and highly dynamic research field.Technology, Policy and Managemen
Preparação de fibras de micro-extração em fase sólida recobertas com poli(dimetilsiloxano) por processo sol-gel: aplicação para determinação de btex em amostras aquosas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Química.Neste trabalho foi explorado e comparado a utilização do suporte de vidro cerâmico frente ao suporte de fibra ótica para confecção de fibras de SPME. Ambos os suportes foram recobertos com PDMS através do processo sol-gel. Testes de absorção e análise da morfologia do recobrimento foram utilizadas para comparação dos dois suportes propostos. As fibras foram utilizadas para o desenvolvimento de metodologia para a determinação de BTEX em amostras aquosas sintéticas e águas de poços de monitoramento localizados em postos de combustíveis. O recobrimento dos suportes mostrou-se eficiente, sendo que foi obtido o melhor recobrimento quando foi utilizado a temperatura de 25 ºC com 3 ciclos de recobrimento de 24 h para ambos os suportes. Nessas condições a fibra com suporte de vidro cerâmico apresentou cerca de 44 m de espessura e mostrou eficiência de extração superior a fibra ótica recoberta. A repetibilidade de extrações de BTEX utilizando uma única fibra de PDMS com vidro cerâmico foi inferior a 5%, enquanto que para fibra ótica ficou em torno de 11%. A reprodutibilidade de confecção das fibras, foi inferior a 7% para fibra de vidro cerâmico e em torno de 11,6% para fibra ótica. Os limites de detecção para a fibra com suporte de vidro cerâmico foram na ordem de 0,2 g L-1, apresentando linearidade em torno de 0,999 e faixa dinâmica de trabalho de 25 a 2000 g L-1
SIMPLE ENTRAPMENT OF ALCALASE IN DIFFERENT SILICA XEROGELS USING THE TWO STEPS SOL-GEL METHOD
No full textThe present study has focused on the entrapment of Alcalase in different xerogels
obtained by using various molar ratios of methyltriethoxysilane, dimethyldietoxisilane and
tetraethoxysilane. Silica and their derivatives were characterized with regard to specific
surface area (nitrogen adsorbtion), chemical composition (Fourier transform infrared
spectroscopy (FT-IR)), weight loss upon heating (thermogravimetric analysis (TGA)) and
catalytic activity
Al-doped Zinc Oxide as a Transparent Conductive Material
No full textZnO powders containing from 1-8 atom% aluminium ions were prepared from aqueous citrate-aminoalcohol-based gels calcined at 500◦C. The powders were characterized using 27Al NMR, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Solid state 27Al NMR clearly distinguished between different Al environments and was effective in determining the relative amounts of incorporation of Al dopant ions into the different Zn lattice sites in the zincite structure. A degree of control over dopant placement is demonstrated by modifying sol precursors and processing parameters, which allowed a syn- thesis protocol to be developed to optimise the doping effectiveness. Relatively minor variations in processing conditions can influence the degree and mode of Al incorporation. Thin films (ca 100 nm) were fabricated by spin-coating the Al-doped Zinc citrate sol-gels onto glass and quartz substrates, followed by a drying step and annealing at 500◦C. The degree of crystal alignment in thin films, deter- mined by X-ray diffraction studies, was found to be influenced by both the dopant level and the heating profile. Resistivity measurements showed films with 0.5-1atom %Al and multiple layers which had been heated at 90◦C before annealing at 500◦C, and subjected to post-annealing treatment under vacuum displayed the lowest resistivities. Further post-annealing treatment at 500◦C under H2/N2 reduced resistivities by an order of magnitude. Transparencies for all films were above 80% in the visible range, and thicker multi-layer films generally demonstrated lower transmittances. Preferential c-axis orientation was observed for all films, but showed higher intensities with increasing film thickness, and for films subjected to directional heating on a hotplate. Increased film thickness gave films with lower resistivities, but also lower transparencie
“Maistre (certa)”. Niveaux de savoir et conception du monde chez Guillaume IX d’Aquitaine
No full textStarting with a study by M. Black (Models and Archetypes, 1958), the author examines the possibility of broadening this heuristic perspective to include literature. In particular, she analyses a text by William IX, in which the troubadour seems identify himself with God
Oltre lo specchio: il Joufroi de Poitiers e la cultura lirica del suo autore
No full textCome è stato a più riprese osservato, il Joufroi de Poitiers, romanzo d’autore borgognone collocabile verso la metà del XIII secolo, si ispira molto da vicino alla figura di Guglielmo IX d’Aquitania, grande signore e primo trovatore di cui ci siano giunti i componimenti. Ma a quali materiali si ispira veramente l’autore del Joufroi? Alla vida provenzale conservata, o piuttosto a una più ampia biografia latina perduta, o ad altri testi ancora? La presente ricerca cercherà di mettere in luce quali siano state le effettive fonti del romanzo e di abbozzare un’ipotesi che spieghi le motivazioni di questi recuperi.As has been repeatedly noted, Joufroi de Poitiers, a novel written by a Burgundian author and composed around the middle of the thirteenth century, is based very closely on the figure of William IX of Aquitaine, great lord and first troubadour whose poems have been compiled. But what materials did truly inspire the author of Joufroi? The extant Provençal vida, or rather a lost broader Latin biography, or still other texts? This research will try to shed light on what were the actual sources of the novel and to outline a hypothesis that explains the motivations of these works
Proceedings of the Per Bruun Symposium
No full textHolocene sea level rise, shoreline erosion and the Bruun Rule-overview (J.J. Fisher) The Bruun Rule: A historical perspective (M.L. Schwartz and V. Milicic) Hypothetical shore profiles in response to rising water level (R.N. Dubois) Shoreline erosion, Rhode Island and North Carolina coasts-test of Bruun Rule (J. J. Fisher) An application of the Bruun Rule in the Chesapeake Bay (P.S. Rosen) Bruun's Concept applied to the Great Lakes (E.B. Hands) Enigma of the Bruun's formula in shore erosion (H. Allison) The 11 Bruun Rule", Discussion on boundary conditions (P. Bruun)KWP-collectio
Entrapment of hemocyanin conformers as a tool for the definition of the structural model of cooperativity
No full textAllostery has been established as a fundamental mechanism of regulation in most biological processes (Changeux, 2012). The most studied allosteric protein is hemoglobin, that has long been considered a paradigm for the investigation of allostery and cooperativity in macromolecules (Cui & Karplus, 2008). A phenomenological characterization of the cooperative oxygen binding in hemoglobin has been given by the classic Monod, Wyman, Changeux model (MWC) (Monod et al., 1965), which described the cooperativity process as the allosteric transition between two different allosteric conformers: the high oxygen affinity R-state and the low oxygen affinity T-state.
In this work we wanted to characterize the highly cooperative oxygen binding process of the hemocyanin (in its dodecameric state) from the arthropod Carcinus aesturaii, which represents a more complex case study. To this aim the functional and structural properties of the different conformational states were investigated, through the encapsulation of the hemocyanin into a sol-gel matrix to avoid the allosteric transition between T- and R-state.
Firstly we characterized the structural and optical properties of the sol-gel matrix in order to find the better conditions for protein encapsulation. The effect of the pH, glycerol and aging time was assessed by collecting Small Angler X-Ray Scattering spectra of undoped sol-gel matrices at ELETTRA (Trieste, Italy). The fractal analysis of all the spectra did not evidence any significant effect of the three factors on the properties of the matrix, with the exception of the decrease of the radius of the silica particles that form the gel network in presence of glycerol. Moreover, the spectroscopic analysis of the undoped matrix revealed a good transparence of the matrix.
The key point of the work was to evaluate if the sol-gel matrix was a suitable way for the entrapment of hemocyanin in a single conformational state, through the analysis of the oxygen binding curves and the Hill-plots of the hemocyanin entrapped into the silica matrix (in presence and absence of oxygen). The results suggested that the sol-gel matrix can avoid the allosteric transitions, although the full entrapment of distinct conformers strongly depend on the pH. Oxygen binding experiments performed in presence of different concentrations of salt demonstrated that changes of the charge to charge interactions between protein and matrix may play an important role in conformational entrapment. The entrapment of different conformers was confirmed by spectroscopic analysis that revealed small but significant differences in the shape of the CD-spectra in the aromatic region and shifts of the peaks of fluorescence emission for the two conformers.
To verify if the oxygen equilibrium data were in agreement with the MWC model we compared the equilibrium constants of the curves obtained by the hemocyanin entrapped into the sol-gel with those predicted by the model, suggesting that the cooperativity in this hemocyanin occurs in a more complicated way. A three-state model was proposed.
The validation of the three-state model was performed through Small Angle Neutron Scattering (SANS) measurements at ILL neutron radiation facility (Grenoble, France), that allowed us to characterize the structure of the conformers both in the oxy- and deoxygenated state. The analysis of the SANS spectra seems to confirm the presence of three different conformers, with a different arrangement of the two hexamers.
In order to determine if these differences in the quaternary structure were correlated to changes in the active sties, we collected XAS spectra at ESRF (Grenoble, France), which shown differences between the different conformers, suggesting a different coordination geometry of the active sites in the deoxygenated form.
An investigation of the functional and structural effects of the positive allosteric effector lactate was also performed, by the analysis of oxygen binding curves and SANS spectra.
In conclusion, with this work it is defined a structural model of cooperativity for hemocyanin, with a functional and structural characterization of the different conformers. We also proposed a possible mechanism to describe how the quaternary conformational changes are linked to the different coordination geometry of the active site during the oxygen binding process.
This study method can be exported to other cooperative systems and the results also provide a solid start point for the development of an oxygen biosensor
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