Dissertations / Theses: '5o3'

1

Santana, Marcos Cleison Silva. "Síntese e caracterização estrutural e magnética das perovskitas complexas ReFe0:5M0:5O3 (Re = Dy, Gd, Sm, Eu,Nd ; M= Mn,Al)." Universidade Federal de Sergipe, 2015. https://ri.ufs.br/handle/riufs/5280.

Full text

Abstract:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Samples of Bi 2Fe4O9 mullite and ReFe 0.5M0.5O3 (Re = Nd, Sm, Eu, Gd, Dy; M = Mn, Al) complex perovskites were successfully synthesized by using the combustion synthesis method. While the mullite was obtained after thermal treatment at temperatures below 1000ºC, complex perovskites are produced after thermal treatments between 1250ºC and 1500ºC for at most 24 h. The X-ray diffraction data analysis suggests the formation of single phase orthorhombic structure, after suitable heat treatment. Scanning electron microscopy (SEM) revealed the formation of micrometric grain size, giving to the sample the relative density. EDS spectra confirmed the homogeneity and purity of complex perovskites. Magnetization measurements as a function of field and temperature showed the diversity of magnetic behavior of the samples. Among the behaviors we can highlight the reorientation of spin for ortoferritas ReFe0.5Mn0.5O3 (Re = Dy, Gd, Eu, Sm, Eu) and ReFe0.5Al0.5O3 (Re = Dy, Nd). Another interesting finding was the effect of magnetic reversal of the samples ReFe0.5Al0.5O3 (Re = Nd, Gd) and EuFe0.5Mn0.5O3. Raman spectra show anomalous bands of second order in the perovskite DyFe0.5Al0.5O3 with characteristics of resonant effects. The evolution of the band associated with the symmetric vibrational mode of the octahedron shows hardening at the temperature range of ordered magnetic phase, thus suggesting a possible spin-phonon coupling. Depolarization current measurements highlights a relaxation process due to charge carriers in the samples ReFe0.5Mn0.5O3 (Re = Dy, Gd). The application of magnetic field profoundly influences the depolarization current behavior of DyFe0.5Mn0.5O3. Dielectric permittivity measurements showed no anomalies between 10 K and 300 K, that could can be associated to a ferroelectric phase.
Amostras da mulita Bi2Fe4O9 e das perovskitas complexas ReFe0.5M0.5O3 (Re= Nd, Sm, Eu, Gd, Dy; M = Mn, Al) foram sintetizadas com sucesso utilizando o método de síntese por reação de combustão. Enquanto a mulita foi obtida após tratamento térmico com temperaturas abaixo de 1000ºC, as perovskitas complexas foram produzidas após tratamentos térmicos entre 1250ºC e 1500ºC por, no máximo, 24 h. A análise de dados de difração de raios X sugerem a formação de estruturas ortorrômbicas de fase única, após os tratamento térmico apropriado. Medidas de microscopia evidenciaram formação de grãos micrométricos conferindo às amostras relativa densidade. Os espectros EDS confirmaram a homogeneidade e pureza das perovskitas complexas. As medidas de magnetização em função do campo e da temperatura evidenciaram a diversidade de comportamentos magnéticos das amostras estudadas. Entre os comportamentos destacamos reorientação de spin para as ortoferritas ReFe0.5Mn0.5O3 (Re = Dy, Gd, Eu, Sm, Eu) e ReFe0.5Al0.5O3 (Re = Dy,Nd). Outro interessante achado foi o efeito de inversão magnética das amostras ReFe0.5Al0.5O3 (Re = Nd, Gd) e EuFe0.5Mn0.5O3. Espectros Raman demonstram bandas anômalas de segunda ordem na perovskita DyFe0.5Al0.5O3 com características de efeitos ressonantes. A evolução da banda associada ao modo vibracional simétrico do octaedro apresenta endurecimento em temperaturas na faixa da fase magnética ordenada, sugerindo assim, um possível acoplamento spin-f onon. Medidas de corrente de despolarização destaca um processo de relaxação devido aos portadores de cargas nas amostras ReFe0.5Mn0.5O3 (Re=Dy,Gd). A aplicação de campo magnético influencia profundamente o comportamento da corrente de despolarização do DyFe0.5Mn0.5O3. Medidas de permissividade dielétrica não exibiram anomalias entre 10 K e 300 K que possam a ser associadas a uma fase ferroelétrica.

APA, Harvard, Vancouver, ISO, and other styles

2

Bräuninger, Sascha Albert [Verfasser], Hans-Henning [Gutachter] Klauß, and Joachim [Gutachter] Wosnitza. "Low-Energy Spin Dynamics in geometrically frustrated 3d-Magnets and Single-Ion Spin Systems : µ+SR studies on BaTi0:5Mn0:5O3 and NaCaCo2F7 and 57Fe-Mössbauer spectroscopy on Fe-diluted Li2(Li1-xFex)N / Sascha Albert Bräuninger ; Gutachter: Hans-Henning Klauß, Joachim Wosnitza." Dresden : Technische Universität Dresden, 2020. http://d-nb.info/1227893248/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Giannoni, Paolo. "Indagini di linguistica geografica : biologia e sociologia linguistica ell'AIS, con rilettura della doppia inchiesta di Firenze (Punto 523) e ripetizione dell'inchiesta di Radda in Chianti (Punto 543) /." [S.l.] : [s.n.], 1993. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

León, Arteaga Angélica M. de. "Spatial Objective Analysis of Oceanographic Variables. An Application to the Ebro Delta Shelf/Slope Domain (North- Western Mediterranean)." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/6383.

Full text

Abstract:

In this research we tested two data analyses methodologies, namely the empirical orthogonal functions (EOFs) to estimate hydrographic CTD data profiles, and a successive corrections algorithm (SC) to project the results onto two dimensional grids, whose superposition leads to a quasi-three dimensional array, on the Ebro Delta shelf/slope domain. The EOFs as an extrapolation procedure with shallow casts was also tested with thickness profiles, for an adequate set of extrapolated profiles might render reliable geostrophic currents on the shelf. The reference level of no motion for the relative geostrophic currents was 500 m. The resulting currents were contrasted with the ones obtained with a classical methodology for shelf domains proposed by Csanady (1979). Another important goal was to test the potential use of linearly independent basic profiles vector modes derived from historic data, to reproduce the data from the oceanographic campaigns.
We used CTD data from four oceanographic campaigns on the Ebro Delta region under different conditions: FANS I - autumn, FANS II - winter, FANS III - summer and MEGO 94, a previous winter campaign, showed atypical winter conditions, with open ocean dynamics that differed significantly from the shelf ones.
We find that the EOFs applied to hydrographic variables with the self campaign eigenvectors renders very good results (expressed as variance explained percentage), when a non-standardized analysis is used (in which the variability is assumed to be unevenly distributed in the water column, as occurs in the ocean). Good results are also obtained when the variability is assumed to be evenly distributed (standardized analysis). When the historic eigenvectors are used, together with the campaign data, a larger number of modes needs to be included. The results are very good for the summer-FANS III and winter-FANS II campaigns. On the other hand, some significantly large errors are obtained for EOF-standardized density with the autumn-FANS I and the winter-MEGO 94 campaings.
The projection of the EOFs results onto a 2.5 x 2.5 km 2D grid were carried out through a SC algorithm. Some unreliable distributions are obtained with the standardized density analysis, due to the differences of the open ocean and shelf distributions, which in turn lead to a very wide range of mode amplitudes. This lead us to test the interpolation of the estimated profiles instead of the amplitude values, improving the results in a significant manner.
The geostrophic circulation obtained with Csanady's method renders spurious along-transect values. While this method has been successfully used on other shallow regions, the abrupt shelf/slope topography of the Ebro Delta, together with the integration path, render it unreliable. The EOFs estimates with the self-campaign eigenvectors tend to approach well the dynamic height distributions of outer slope and open ocean, particularly the non-standardized analysis. The estimates on the shelf circulation seem to be reliable in two campaigns only. Since no current ADCP data is available in any of the campaigns, a quantitative evaluation is not possible. The use of historic eigenvectors does not contribute to a better estimate of the shelf circulation.

APA, Harvard, Vancouver, ISO, and other styles

5

Šoukal, David. "Měřicí funkce spektrálního analyzátoru N1996A-503." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218014.

Full text

Abstract:

The theme of this diploma work is to introduce spectrum analzyer Agilent CSA N1996A to readers. In the work there are explained in detail all measuring functions of this machine, there are also mentioned all engineering characteristics and described all operating elements of this machine. In the diploma work is also mentioned the basice division of spectrum analyzers and their principles of activity. In the pracical part there are proposed the measurement assignments for hearers of subject MEMT, where is the possibility to use already mentioned spectrum analyzer. Including of the assignments there are also theoretical analysis of each assignment, their diagrams of wiring, practical metering and interpretation of results.

APA, Harvard, Vancouver, ISO, and other styles

6

Nonxuba, Philile Zipho. "An evaluation of the Nelson Mandela Metropole as a location to attract investment." Thesis, Rhodes University, 2006. http://eprints.ru.ac.za/513/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Cosgrove, Jeffrey John. "Marine phytoplankton primary production and ecophysiology using chlorophyll-A fluorescence." Cosgrove, Jeffrey John (2007) Marine phytoplankton primary production and ecophysiology using chlorophyll-A fluorescence. PhD thesis, Murdoch University, 2007. http://researchrepository.murdoch.edu.au/503/.

Full text

Abstract:

Marine phytoplankton ecophysiological state and primary production measurements have typically been controversial due to potential impacts of measurement techniques. Advances in chl-a fluorescence techniques have provided a means for rapid, non-invasive measurement of electron transport through photosystem 2 (PSII) in dilute phytoplankton suspensions. While studies on higher plants have outlined a close relationship between PSII electron transport and carbon fixation, results from studies on microalgae reveal significant variations in the relationship. Three species of phytoplankton representing three major taxonomic groups of the marine phytoplankton were used in this study: (1) Chaetoceros muelleri CS176 Lemmermann (Bacillariophyta), (2) Isochrysis galbana CS177 Parke (Haptophyta) and, (3) Nannochloropsis oculata CS179 (Droop) Hibberd (Ochrophyta, eustigmatophyte). Each species was cultured in semicontinuous culture and primary production was estimated using oxygen evolution and carbon fixation techniques and compared against predictions based on chl-a fluorescence measurements. It was found that predicted values of primary production both under-estimated and overestimated actual carbon fixation measured via radioisotope (14C) techniques. This variation was primarily explained by probable errors in the assumed values for PSII density. The relationship between oxygen evolution or carbon fixation with chl-a fluorescence-derived measures was commonly linear below the light saturation parameter, with a departure from linearity occurring at higher irradiances. This departure from linearity was greatest in cultures adapted to low light conditions. At higher light intensities alternative electron pathways such as the Mehler reaction and/or chlororespiration are likely to be more active in low light-adapted cultures, leading to this greater non-linearity. Chl-a fluorescence measurements were also found to be a useful in characterising ecophysiology using photosynthesis-versus irradiance curves. However, an important caveat on this is the measurement of PSII density ([eta]PSII) rather than use of an assumed value as changes in [eta]PSII can have a profound impact on light curve parameters. A field study in Fremantle Harbour found a healthy (negligible nutrient starvation), diatom dominated, phytoplankton community. Results suggest that phytoplankton are able to begin boosting photosynthetic capability just prior to morning twilight. Waters in the harbour were well mixed via tidal motion and substantial midday photoinhibition was not observed. Data suggest levels of primary production at the mouth of the harbour are similar to those of coastal waters in the plume of the Ocean Reef wastewater outfall.

APA, Harvard, Vancouver, ISO, and other styles

8

Chan, Chim Yuk Marc. "The relationship between textual criticism and the synoptic question: a study based on the passion narrative." Chan Chim Yuk, Marc (2005) The relationship between textual criticism and the synoptic question: a study based on the passion narrative. PhD thesis, Murdoch University, 2005. http://researchrepository.murdoch.edu.au/513/.

Full text

Abstract:

Since the eighteenth century, various hypotheses have been proposed by scholars in an attempt to solve the Synoptic Question. Most of these scholars have used more or less the same Greek text, yet they have come up with different conclusions. So, the question arises whether it is possible to find a trend in the manuscripts dating up to the fifth century which sheds additional clues on the relationships among the Synoptic Gospels. To address this, I have taken the text of the 27th edition of Nestle-Aland as the basis for analysis through the use of the colour-coded scheme proposed by the Karawara Gospels Project. However, in the same colour-coding exercise, the variant readings from the relevant manuscripts are also displayed. This facilitates the identification of any particularities. Since the Synoptic Gospels contain too much to cover within the constraints of this research project, there is a need to select enough material to make the study relevant. The passion narrative has been selected on the basis of its content and the generally agreed closeness of the texts in all three Synoptic Gospels. So, all the sections, as defined in the Aland Synopsis, in the Triple Tradition are colour-coded and analysed. The relevant variant readings in these sections are also taken into consideration. To display the colour-coding more accurately, it was found that a commonly used and available format is more appropriate since printing is still not a viable alternative. Thus, all the colour-coded sections, as found on the attached CD ROM, are converted into the PDF format and the Adobe Acrobat Reader, widely available through the Internet, can be used to view them. This study has pointed out that in spite of the commonly agreed closeness of the texts, that of Luke varies quite markedly from the other two.

APA, Harvard, Vancouver, ISO, and other styles

9

Bedigan, Kirsten M. "Boeotian Kabeiric ware : the significance of the ceramic offerings at the Theban Kabeirion in Boeotia." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/503/.

Full text

Abstract:

This study presents a re-evaluation of the ceramic material from the sanctuary of the Kabeiroi at Thebes in Boeotia. The lack of relevant literary evidence necessitates a reliance on the archaeology as the primary means of interpretation. In particular the archaeological context and iconography of the ceramics offer an interesting and highly unusual perspective into the secretive and often peculiar nature of the Kabeiric cult. Previous studies conducted on the ceramic material have only considered it in iconographic terms, yet by reappraising the data using an analytical approach and socio-archaeological theory it is possible to acquire a deeper understanding of the operation of this cult. By examining the form and function of the ceramics we can elicit inferences relating to the role of wine and intoxication within the rituals of the sanctuary. Comparative studies between form and iconography can further develop our interpretations of the scenes as representations of cult practices. The evidence is further scrutinised for indications as to whether the Theban site is characteristic of the Kabeiric cult as a whole, or if its unique iconography demonstrates its individuality within the ancient world. The data from other Kabeiric and non-Kabeiric sanctuaries clearly indicates that cults within the Greek world were experiencing parallel development in relation to their ceramic usage. Furthermore, the ceramic material from purely Kabeiric sites also shows the same biases in the archaeological record with an emphasis on the preparation and consumption of wine. Extending this research to other archaeological material also implies a common iconographic heritage stretching beyond the boundaries of the Theban site. By considering the ceramics in a more analytical manner than that of previous research – combining archaeological, anthropological and art historical models – we can move away from the premise that the decorated Greek vase is merely a work of art. Instead it is possible to detail the sanctuary’s evolution through the development of the ceramics and to offer insights into the society that produced and utilised them.

APA, Harvard, Vancouver, ISO, and other styles

10

Denley, Simon M. "The role of the systemic inflammatory response, the JAK STAT pathway and the MAPK pathway in the prognosis of resectable pancreatic cancer." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/523/.

Full text

Abstract:

Pancreatic cancer is a devastating disease with a five year survival of only 2-3%. Only 10-15% of patients have resectable disease at presentation and the only potential cure is major surgery with adjuvant chemotherapy. The outcomes of surgery are disappointing with a median survival of only15-17 months and operative mortality and morbidity figures of 5-10% and 40% respectively. This abysmal prognosis is likely due to the highly aggressive nature of the tumour, its resistance to adjuvant therapy, its late presentation and the likely presence of micro-metastases not detectable at staging or surgery. A pre-operative systemic inflammatory response (as measured by CRP) is known to be associated with a poor prognosis in a number of cancers including pancreatic cancer. The reasons behind this poor prognosis are not yet known. The main driver of plasma CRP levels is the cytokine IL-6, known to be elevated in the plasma of patients with pancreatic cancer. This thesis hypothesises that upregulation of two IL-6-dependent pathways, the JAK STAT and MAPK pathways is responsible for the poor prognosis associated with an inflammatory response in pancreatic cancer. Both of these pathways are known to be involved in cellular growth, differentiation and apoptosis and when activated they may confer a growth or survival advantage to tumour cells. The aims of this thesis were to establish the prognostic role of a systemic inflammatory response in resectable pancreatic cancer in both a retrospective and prospective cohort and establish whether increased protein expression in either the JAK STAT or MAPK pathways is associated with a poor prognosis in the same retrospective cohort. A retrospective database of 148 patients who had undergone Whipple resection for either pancreatic cancer (PC) or non-pancreatic peri-ampullary cancer (NPPC) was created with pre-operative CRP values and survival data. The author then created tissue micro-arrays (TMA’s) with both tumour and normal pancreatic duct tissue from each of the 148 patients in the retrospective cohort and carried out immunohistochemistry on 12 antibodies known to be crucial in IL-6 signalling (6 in the JAK STAT and 6 in the MAPK pathways). Following staining the author scored each of the antibodies using the weighted histoscore to allow analysis of antigen expression. During the period of research the author also created a prospective database of 36 patients who underwent surgery for either PC or NPPC. Plasma was stored pre-operatively from each of the patients and this was later thawed and using an ELISA kit another research fellow (JL) was able to establish plasma levels of IL-6 in the prospective cohort. On univariate analysis a raised pre-operative CRP was associated with poorer survival, 374 days versus 618 days (p=0.0001) in the retrospective PC group only. On multivariate analysis, only pre-operative CRP retained statistical significance amongst those factors shown to be significant on univariate analysis (P=0.009). In the prospective group, patients with low levels of IL-6 had a median survival of 799 days, against a median survival of 537 days in those with high plasma IL-6 levels (P=0.002) when all 36 patients were analysed together. On analysis of protein expression, no significant relationship between increased expression and poor survival was seen for any of the 12 proteins analysed. The results from this thesis confirm that a pre-operative inflammatory response is associated with poor survival in patients with resectable pancreatic cancer. Raised plasma levels of IL-6 are also associated with poorer survival in similar patients. However, the poor prognosis appears to be via a JAK STAT/ MAPK independent mechanism. Other possible explanations for this poor prognosis including the connection between inflammation and cachexia and other important inflammatory proteins such as NF-κB and SOCS are explored in the discussion of this thesis.

APA, Harvard, Vancouver, ISO, and other styles

11

Murray, Alicia. "Interactions between potassium channels and serotonin in pulmonary arterial hypertension." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/563/.

Full text

Abstract:

Pulmonary arterial hypertension (PAH) is a progressive disease which results from increases in mean pulmonary artery pressure and pulmonary vascular resistance. If untreated it leads to right ventricular failure and death. 5-Hydroxytryptamine (5-HT) has been implicated in the disease process and is thought to promote both vasoconstriction and remodelling of the pulmonary vasculature. The activity of potassium ion (K+) channels plays a major role in influencing pulmonary artery tone by regulating resting membrane potential, intracellular Ca2+ concentration and contraction of vascular smooth muscle. This study aimed to investigate possible interactions between 5-HT and K+ channels in the development of PAH in the mouse. The actions of 5-HT and a range of K+ channel blockers were investigated on isolated intralobar pulmonary arteries (IPA) from wild type (WT) mice and mice over-expressing the serotonin transporter (5HTT), which spontaneously develop PAH. Both 5-HT and linopirdine, a KCNQ K+ channel inhibitor, were found to induce contraction of IPA, but were more potent in IPA from WT mice than 5-HTT+ mice. The 5-HT induced vasoconstriction was found to involve influx of Ca2+ from the extracellular space, Ca2+ release from the sacroplasmic reticulum and a rho kinase–dependent increase in the sensitivity of the contractile machinery of pulmonary artery smooth muscle cells (PASMC) to intracellular Ca2+. Ca2+ entered the cell via both voltage operated calcium channels (VOCC), activated by membrane depolarisation, and a separate Ca2+ entry pathway, the latter appearing to contribute more in 5-HTT+ mice. The effects of linopirdine were shown to be due entirely to the entry of Ca2+ through VOCC in both WT and 5-HTT+ mice IPA. The difference in vasoconstrictor potency between WT and 5HTT+ mice was not seen with any other K+ channel blocker, suggesting a selective loss of KCNQ channels and/or VOCC in PAH resulting from 5HTT over expression. KCNQ channel activity was further investigated using the KCNQ channel openers, flupirtine and retigabine. These agents were more potent in dilating IPA from WT mice compared to 5-HTT+ mice, consistent with the loss of expression or activity of KCNQ channels in 5-HTT+ mice. Despite this, orally administered flupirtine was shown to reverse two indices of established PAH in the 5HTT+ mice; right ventricular pressure and right ventricular hypertrophy. This action of flupirtine was also seen in chronic hypoxic mice, where it prevented the development of PAH. In conclusion, this study provides evidence of an interaction between KCNQ channels and the 5-HT system in the development of PAH. By showing that a KCNQ channel opener can attenuate PAH, both in the developing and established disease situation, this study proposes a new potential therapeutic target in the treatment of PAH.

APA, Harvard, Vancouver, ISO, and other styles

12

Atepor, Lawrence. "Vibration analysis and intelligent control of flexible rotor systems using smart materials." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/593/.

Full text

Abstract:

Flexible rotor-bearing system stability is a very important subject impacting the design, control, maintenance and operating safety. As the rotor bearing-system dynamic nonlinearities are significantly more prominent at higher rotating speeds, the demand for better performance through higher speeds has rendered the use of linear approaches for analysis both inadequate and ineffective. To address this need, it becomes important that nonlinear rotor-dynamic responses indicative of the causes of nonlinearity, along with the bifurcated dynamic states of instabilities, be fully studied. The objectives of this research are to study rotor-dynamic instabilities induced by mass unbalance and to use smart materials to stabilise the performance of the flexible rotor-system. A comprehensive mathematical model incorporating translational and rotational inertia, bending stiffness and gyroscopic moment is developed. The dynamic end conditions of the rotor comprising of the active bearing-induced axial force is modelled, the equations of motion are derived using Lagrange equations and the Rayleigh-Ritz method is used to study the basic phenomena on simple systems. In this thesis the axial force terms included in the equations of motion provide a means for axially directed harmonic force to be introduced into the system. The Method of Multiple Scales is applied to study the nonlinear equations obtained and their stabilities. The Dynamics 2 software is used to numerically explore the inception and progression of bifurcations suggestive of the changing rotor-dynamic state and impending instability. In the context of active control of flexible rotors, smart materials particularly SMAs and piezoelectric stack actuators are introduced. The application of shape memory alloy (SMA) elements integrated within glass epoxy composite plates and shells has resulted in the design of a novel smart bearing based on the principle of antagonistic action in this thesis. Previous work has shown that a single SMA/composite active bearing can be very effective in both altering the natural frequency of the fundamental whirl mode as well as the modal amplitude. The drawback with that design has been the disparity in the time constant between the relatively fast heating phase and the much slower cooling phase which is reliant on forced air, or some other form of cooling. This thesis presents a modified design which removes the aforementioned existing shortcomings. This form of design means that the cooling phase of one half, still using forced air, is significantly assisted by switching the other half into its heating phase, and vice versa, thereby equalising the time constants, and giving a faster push-pull load on the centrally located bearing; a loading which is termed ‘antagonistic’ in this present dissertation. The piezoelectric stack actuator provides an account of an investigation into possible dynamic interactions between two nonlinear systems, each possessing nonlinear characteristics in the frequency domain. Parametric excitations are deliberately introduced into a second flexible rotor system by means of a piezoelectric exciter to moderate the response of the pre-existing mass-unbalance vibration inherent to the rotor. The intended application area for this SMA/composite and piezoelectric technologies are in industrial rotor systems, in particular very high-speed plant, such as small light pumps, motor generators, and engines for aerospace and automotive application.

APA, Harvard, Vancouver, ISO, and other styles

13

Vijayakrishnan, Swetha. "The architectural complexity of the human PDC core assembly." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/573/.

Full text

Abstract:

The mammalian pyruvate dehydrogenase complex (PDC) is a key multi-enzyme assembly linking the glycolytic pathway to the TCA cycle via the specific conversion of pyruvate to acetyl CoA and, as such, is responsible for the maintenance of glucose homeostasis in humans. PDC comprises a central pentagonal dodecahedral core of 60 dihydrolipoamide acetyltransferase (E2) and 12 E3 binding protein (E3BP) subunits. Presently, two conflicting models of PDC (E2+E3BP) core organisation exist: the ‘addition’ (60+12) and ‘substitution’ (48+12) models. In addition to its catalytic role, the multi-domain E2/E3BP core provides the structural framework to which 30 pyruvate decarboxylase (E1) heterotetramers and 6-12 dihydrolipoamide dehydrogenase (E3) homodimers are proposed to bind at maximal occupancy. The formation of specific E2:E1 and E3BP:E3 subcomplexes are characteristic of eukaryotic PDCs and are critical for normal complex function. Despite the availability of limited structural data, the exact subunit organisation and mechanism of operation of the mammalian E2/E3BP core remains unknown. This thesis describes the large-scale purification of tagged, recombinant human PDC cores, full-length rE2 and rE2/E3BP, truncated E2/E3BP, peripheral rE3 enzyme as well as native E2/E3BP core (bE2/E3BP) purified from bovine heart. The ability to purify large amounts of pure protein has enabled the characterisation of the individual cores as well as the E2/E3BP:E3 complex using a variety of biochemical and biophysical techniques. Full-length rE2/E3BP, rE2, bE2/E3BP, truncated E2/E3BP (tLi19/tLi30) and rE2/E3BP:E3 were analysed in solution by analytical ultracentrifugation (AUC). While AUC of the cores supported the substitution model of core organisation, the stoichiometry of interaction was determined to be 2:1 (rE2/E3BP:E3). This was further complemented by gel filtration chromatography (GFC) and small angle neutron scattering (SANS), implying the possible existence of a network of E3 ‘cross-bridges’ linking pairs of E3BP molecules across the surface of the E2 core assembly. Low resolution solution structures obtained for rE2/E3BP, bE2/E3BP and tLi19/tLi30 by small angle x-ray scattering (SAXS) and SANS revealed the presence of icosahedral cores with open pentagonal faces favouring the substitution model of core organisation. These solution structures also indicated high structural similarity between the recombinant and native cores, as well as with the crystal structure obtained previously for the truncated bacterial E2 core. In addition, homology modelling and superimpositions of high- and low-resolution structures of the core revealed conservation of the overall pentagonal dodecahedral morphology despite evolutionary diversity. Evidence for the substitution model of core organisation was further substantiated by negative stain EM of the recombinant and bovine E2/E3BP cores. SANS stoichiometry data indicated the binding of 10 E3 dimers per E2/E3BP core. Although this could correspond to approximately 1:1 stoichiometry between E2/E3BP:E3, subsequent radiolabelling studies suggested possible variation in core subunit composition between the native and recombinant E2/E3BP cores. Therefore, as opposed to the 48E2+12E3BP substitution model based on AUC and SAXS studies with the recombinant E2/E3BP core, rE2/E3BP cores produced in this study indicated a higher level of incorporation of E3BPs with a maximum core composition of 40E2+20E3BP. On the basis of this new finding we have proposed the ‘variable E3BP substitution model’, wherein the number of E3BPs within the core can range from 0 to a maximum of 20, thus resulting in variable populations of E2/E3BP cores. Despite this core variability, the highly controlled regulatory mechanisms in vivo may bias the core composition towards an average of 48E2+12E3BP. However, as the over-expression of the recombinant E2/E3BP core in our study is not as tightly regulated as in vivo, higher number of E3BPs (>12) is observed to be integrated into the core. This new level of architectural complexity and variable subunit composition in mammalian PDC core organisation is likely to have important implications for the catalytic mechanism, overall complex efficiency and tissue-specific regulation by the intrinsic PDC kinases (PDKs) in normal and disease states. The E2 cores of the PDC family are known to be highly flexible, exhibiting inherent size variability reflective of the ‘breathing’ of the core. Integration of E3BP into the E2 core assembly would then be expected to have significant consequences for the structural assembly, affecting the ‘breathing’ and in turn the function and regulation of the complex. Unfolding studies to assess core stability via circular dichroism (CD) and tryptophan fluorescence revealed lower stability of the rE2/E3BP core as compared to cores composed exclusively of rE2 subunits, thus implying the contribution of E3BP towards core destabilisation. In addition, crosslinking studies indicated weak dimerisation of rE3BP, which may be a key factor promoting core destabilisation. The lower stability of the E2/E3BP core may be of benefit in mammals where sophisticated fine tuning is required to obtain cores with optimal catalytic and regulatory efficiencies. SAXS solution structures of E2/E3BP cores obtained were unable to locate the exact positions of E3BP within the core. However, SANS in combination with contrast matching of selectively deuterated components as well as cryo-EM, EM tomography and single molecule studies could be used in future for determination of the exact locations of E3BP, and validating the importance of E2/E3BP core organisation and subunit composition for overall PDC function and regulation.

APA, Harvard, Vancouver, ISO, and other styles

14

Athron, Peter. "Aspects of electroweak symmetry breaking in physics beyond the standard model." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/513/.

Full text

Abstract:

Fine tuning in the Standard Model (SM) is the basis for a widespread expectation that the minimal model for electroweak symmetry breaking, with a single Higgs boson, is not realised in nature and that new physics, in addition to (or instead of) the Higgs, will be discovered at the Large Hadron Collider (LHC). However constraints on new physics indicate that many models which go beyond the SM (BSM) may also be fine tuned (although to a much lesser extent). To test this a reliable, quantitative measure of tuning is required. We review the measures of tuning used in the literature and propose an alternative measure. We apply this measure to several toy models and a constrained version of the Minimal Supersymmetric Standard Model. The Exceptional Supersymmetric Standard Model (E6SSM) is another BSM motivated by naturalness. As a supersymmetric theory it solves the SM hierarchy problem and by breaking a new gauged U(1) symmetry it also solves the μ-problem of the MSSM. We investigate the Renormalisation Group Evolution of the model and test for radiative electroweak symmetry breaking in two versions of the model with different high scale constraints. First we briefly look at scenarios with non-universal Higgs masses at the GUT scale and present a particle spectrum that could be observed at the LHC. Secondly we study the constrained E6SSM (CE6SSM), with universal scalar (m0), trilinear (A0) and gaugino (M) masses. We reveal a large volume of CE6SSM parameter space where the correct breakdown of the gauge symmetry can be achieved and all experimental constraints can be satisfied. We present benchmark points corresponding to different patterns of the particle spectrum. A general feature of the benchmark spectra is a light sector of SUSY particles consisting of a light gluino, two light neutralinos and a light chargino. Although the squarks, sleptons and Z′ boson are typically much heavier, the exotic color triplet charge 1/3 fermions as well as the lightest stop can be also relatively light leading to spectacular new physics signals at the LHC.

APA, Harvard, Vancouver, ISO, and other styles

15

Speller, G. M. "A community in transition : a longitudinal study of place attachment and identity processes in the context of an enforced relocation." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/593/.

Full text

Abstract:

This thesis examines the relationship between place and identity; it is concerned with the process of attachment to place and how this process is linked to identity. The study is longitudinal in design and uses both qualitative and quantitative approaches. The context is provided by the enforced relocation of Arkwright Town, a one hundred year old North East Derbyshire mining village, to a near-by site; this research monitors the relocation process over a six year period. This work is framed within the transactional paradigm which assumes that the process of change involves a dynamic confluence of spatial, cultural and temporal aspects and, furthermore, that individuals and groups influence and are influenced by their spatial environment in a way which cannot be described adequately in terms of a direction of causality. It adopts a social constructivist position which accepts that the participants’ ‘reality’ is shaped by the meanings they attribute to their socio-spatial environment; hence the focus of this work is on how participants to this study experienced the socio-psychological changes during and after the relocation. The interview data were analysed using a combination of grounded theory and interpretative phenomenological analysis to identify the meanings which the relocation had for the participants; a range of theoretical concepts from both social and environmental psychology were then used to interpret participants’ experiences. The findings included participants’ accounts of the degree to which their previous behaviour patterns were disrupted and the meanings which those disruptions held for them. They pointed to interruptions of friendship patterns, to changes in previous privacy regulation mechanisms, and highlighted the degree to which participants’ previous socio-spatial schemata had become redundant after the relocation. It is suggested that the reduced visual access in New Arkwright not only diminished a sense of connectedness to others but also restricted an information flow which had been part of the functioning of the community. Participants’ quotations were also used within the framework of Breakwell’s (1986) Identity Process Theory to investigate the degree to which the participants’ identity processes were affected by the changes in the spatial environment, and especially whether the spatial change threatened or enhanced the four principles of identity described in Breakwell’s theory: self esteem, distinctiveness of the self, self efficacy and continuity of the self. Evidence was found for the important role place has in maintaining and enhancing the four principles of identity and that place is, therefore, an important link to identity. The data show that the relative salience of each identity principle can change over time during a situation of major change and in addition, a marked change from collective to individual functioning was identified. Moreover, participants’ accounts suggested that there are five important factors which, when present, facilitate the development of an emotional bond with place. These are here termed aspects of place attachment; they emerged during the pre-relocation interviews and provide a useful extension of Fuhrer & Kaiser’s (1992) work on attachment to home. Further support for these aspects was found during the post-relocation period both in the qualitative and quantitative data. They comprise a sense of security; a sense of autonomy; the desire and ability to engage in appropriation; an optimal level of internal and external stimulation; and place congruence. Thus this thesis uses existing theory to understand better the effect of the relocation on the villagers; it helps develop the link between environmental and social psychological theory through its investigation of how place can be an integral part of identity, and it extends current theory on place attachment through the concept of the five aspects of attachment to place.

APA, Harvard, Vancouver, ISO, and other styles

16

Vickers, Tom. "The management of oppression : focussing on relationships between refugees and the British state in Newcastle upon Tyne." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/583/.

Full text

Abstract:

This thesis uses an empirically informed Marxist analysis to investigate the role of interests, consciousness and unpaid activity of refugees and asylum seekers in shaping their relationships with the British state, including case studies from the city of Newcastle upon Tyne. I argue that antagonism between the British state and refugees from economically underdeveloped countries is rooted in capitalist relations of production, with Britain occupying an imperialist position. The thesis advances a novel perspective on ‘social capital’, understood as purposive and sustained forms of non-contractual engagement, with implicit norms and values. Social capital is ‘unmasked’ as a way of understanding and intervening in relations at an individual level, in order to influence change at a social level. I argue that the tendency of recent Labour governments’ policy has been to break up social capital formations among refugees which are seen as threatening, whilst actively cultivating formations which engage refugees on an individual basis, as part of managing their oppression. The thesis identifies contradictions and possibilities for resistance within this process, such as simultaneous tendencies for volunteering to contribute to more collective forms of identity and more individualised forms of action. The multi-level research design explores processes connecting the individual to the global. Empirical data is used to interrogate and develop a theoretical framework which is rooted in classical Marxism, draws on insights developed within qualitative social research methods and anti-oppressive practice, and engages creatively with challenges from post-modernism and feminism. The methodology combines: theoretical research; secondary statistics and literature at an international level; interviews with key participants and archival research on local histories of migration and settlement, including three organisational case studies; four contemporary organisational case studies; and individual volunteer case studies based on semi-structured interviews and focus groups with eighteen refugees and asylum seekers.

APA, Harvard, Vancouver, ISO, and other styles

17

Osborn, James. "Proﬁling the turbulent atmosphere and novel correction techniques for imaging and photometry in astronomy." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/513/.

Full text

Abstract:

The turbulent atmosphere has two detrimental eﬀects in astronomy. The phase aberration induced by the turbulence broaden the point spread function (PSF) and limits the resolution for imaging. If there is strong turbulence high in the atmosphere then these phase aberration propagate and develop into intensity fluctuations (scintillation). This thesis describes three novel instruments related to these problems associated with atmospheric turbulence. The ﬁrst is an optical turbulence proﬁler to measure the turbulence strength and its position within the atmospheric surface layer in real-time. The instrument is a development of the slope detection and ranging (SLODAR) method. Results from the prototype at Paranal Observatory are discussed. An instrument to improve the PSF for imaging is also discussed. The instrument works by adaptively blocking the telescope pupil to remove areas which are the most out of phase from the mean. This acts to ﬂatten the wavefront and can therefore be used after an adaptive optics system as an additional clean up, or stand alone on a telescope as a relatively aﬀordable and easy way to improve the PSF. The third instrument reduces the scintillation noise for high precision fast photometry. Simulation results show that it is possible to reduce the scintillation noise to a level where the measurements are photon noise dominated.

APA, Harvard, Vancouver, ISO, and other styles

18

Tattersall, Jamie. "CP-violation in cascade decays at the LHC." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/523/.

Full text

Abstract:

We study the potential to observe CP-violating effects in various supersymmetric cascade decay chains at the LHC. Asymmetries composed by triple products of momenta of the final state particles are sensitive to CP-violating effects. We analytically calculate the cascade decays including the relevant spin correlations to compute the parton level asymmetry. In addition, we use Monte Carlo simulations to estimate the sensitivity of the LHC to the CP-violating observables. Due to large boosts that dilute the asymmetries, these can be difficult to observe at the LHC. However, if all particle masses in a cascade decay are known, it may be possible to reconstruct all momenta in the decay chains. We can then recover the full asymmetry on an event-by-event basis even when we have missing momentum due to a stable lightest supersymmetric particle. After the reconstruction, the non-diluted CP-violating signal gets significantly enhanced so that an observation may become feasible. A fully hadronic study has also been completed to produce the best estimate of the viability of these obseravbles at the LHC. We include both standard model and SUSY backgrounds in the study. Our conclusions state that given a favourable scenario, CP-violation may be observed in SUSY at the 3-sigma level over a wide range of CP-phases with 500 1/fb of data.

APA, Harvard, Vancouver, ISO, and other styles

19

Barres-de-Almeida, Ulisses. "Physics from time variability of the VHE Blazar PKS 2155-304." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/593/.

Full text

Abstract:

Blazars are the principal extragalactic sources of very high energy gamma-ray emission in the Universe. These objects constitute a sub-class of Active Galactic Nuclei whose emission is dominated by Doppler boosted non-thermal radiation from plasma outﬂowing at relativistic speeds from the central engine. This plasma outﬂow happens in the form of large-scale collimated structures called jets, which can extend for Mpc in length and transport energy from the central engine of the galaxy to the larger scale intergalac- tic medium. Over thirty such sources have been discovered to date by ground-based gamma-ray telescopes such as H.E.S.S., and PKS 2155-304 is the prototypical southern-hemisphere representative of this population of objects. In this thesis I have studied in detail some aspects of the temporal variability of the jet emission from PKS 2155-304, combining coordinated observations across the electromagnetic spectrum, from optical polarimetric measurements to X-ray and ground-based gamma-ray data. The temporal properties of the dataset allowed us to derive important physical information about the structure and emission mechanisms of the source and put constraints to the location of the sites of VHE emission and particle acceleration within the jet. We have also derived a sensitive statistical measure, called Kolmogorov distance, which we applied to the large outburst observed from PKS 2155-304 in July 2006, to derive the most stringent constraints to date on limits for the violation of Lorentz invariance induced by quantum-gravity effects from AGN measurements.

APA, Harvard, Vancouver, ISO, and other styles

20

Gillard, Mike. "Solitons and volume preserving flow." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/533/.

Full text

Abstract:

Solitons arise as solutions to non-linear partial differential equations. These equations are only analytically solvable in very few special cases. Other solutions must be found numerically. A useful technique for obtaining static solutions is gradient flow. Gradient flow evolution is in a direction which never increases energy, leading to solutions which are local minima. Here, a modified version of gradient flow referred to as volume preserving flow is introduced. This flow is constructed to evolve solutions towards local minima, while leaving a number of global quantities unaltered. Volume preserving gradient flow will be introduced and demonstrated in some simple models. Volume preserving flow will be used to investigate minimal surfaces in the context of double bubbles. Work will reproduce explicit results for double bubbles on the two-torus and construct a range of possible minimisers on the three-torus. Domain walls in a Wess-Zumino model with a triply degenerate vacuum will be used to represent the surfaces of the bubbles. Volume preserving flow will minimise the energy of the domain walls while maintaining the volumes of the space they contain. Global minima will represent minimal surfaces in the limit in which the domain wall thickness tends to zero. Numerical simulations of solitons in models which have conformal symmetry are problematic. Discretisation breaks the zero modes associated with changes of scale to negative modes. These lead to the collapse of solutions. Volume preserving flow provides a framework in which minimisation occurs orthogonally to these zero modes, maintaining a scale for the minimisation. Two such conformal models which permit Hopf solitons are the Nicole and AFZ models. They are comprised of the two components of the Skyrme-Faddeev model, taken to fractional powers to allow for solitons. Volume preserving flow will be used to find static solutions for a range of Hopf charges for each model. Comparisons will be made with the Skyrme-Faddeev model and general features of Hopf solitons will be discussed. A one parameter family of conformal Skyrme-Faddeev models will also be introduced. These models will be the set of linear combinations of the Nicole and AFZ models where the coefficients sum to one. Energy and topology transitions through this set of models will be investigated.

APA, Harvard, Vancouver, ISO, and other styles

21

Matos, Luis Filipe Pinto T. A. "Supersymmetry breaking : models of gauge mediation with gauge messengers." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/553/.

Full text

Abstract:

With the start of the LHC, it becomes increasingly important to understand the experimental signatures that discriminate different extensions of the standard model. Supersymmetry (SUSY), in particular the Minimal Supersymmetric Standard Model (MSSM), is one such extension that is specially attractive by its simplicity and elegance. However, if this symmetry is to be realized in nature, it must be spontaneously broken. In this work we will try to understand the most general way in which SUSY breaking can happen in renormalizable field theories and the implications that this has on the minimal extension of the standard model (MSSM) mass spectrum. The first two chapters are the introductory material: in chapter 1 we will introduce some of the key ideas necessary to understand supersymmetric field theories, and in chapter 2 we will briefly describe the the simplest supersymmetric version of the Standard Model. In chapter 3 we will focus on understanding the role of R-Symmetry breaking in determining the soft terms gauge mediation of supersymmetry breaking (GMSB) can lead to. To do this we consider a model where both R-symmetry and SUSY are spontaneously broken. One starts with the model proposed by Intriligator, Seiberg and Shih (ISS) and adds a (dangerous) marginal operator, which we call a meson deformation. The inclusion of this operator leads to the spontaneous breaking of R-symmetry in the vacuum. One then gauges the SU(5) of flavour and identifies it with the MSSM GUT gauge group, thus implementing GMSB. This was the second explicit example where R-symmetry was spontaneously broken in the vacuum. As in the first, gaugino masses iii turned out to be smaller than naively expected so that a mild splitting between scalar (squark and slepton) and gaugino masses exists. After this, a general argument showed that in fact gaugino masses are always significantly smaller than scalar masses if the universe is perturbatively stable. This arguments suggests that any viable vacuum should be (perturbatively) metastable, as had been previously noticed by Murayama and Nomura. In chapter 4, we try to explore alternatives to this scenario by considering the possibility that the vacuum doesn’t break supersymmetry by F-term vevs alone, but by a having simultaneously non-zero F and D-terms. It turns out that this does not happen in models where the Kahler potential is canonical, and the superpotential is a cubic polynomial in the fields, but it can happen if either of these constraints is violated. This leads us to consider a particular example, where we study a hidden sector model with SU(3) gauge group, two flavours of quarks and one singlet. The superpotential is the most general consistent with the tree-level symmetries. The R-symmetry is anomalous, however, but one can still derive selection rules that constrain the form of the effective superpotential. The only extra term that is allowed is an instanton induced contribution. This term explicitly breaks the R-symmetry, but the resulting low energy superpotential is not generic and SUSY is still spontaneously broken. While not a complete example of GMSB, this class of hidden sector models is interesting as it does not require metastability: the tension between the spontaneous breaking of an R-symmetry and the massless R-axion is bypassed by the naturally non-generic superpotential. These models usually have both F and D-term SUSY breaking, but these two vevs are not independent: in non-Abelian theories, the D-term vevs can only be induced by the F-term vevs of fields that are not gauge singlets. The implementation of GMSB in scenarios where the F-terms are not gauge singlets is then considered in both its direct and semi-direct forms: iv In chapter 5 we deal with direct gauge mediation with gauge messengers. In this version of gauge mediation, the spontaneously broken gauge group is identified with the MSSM GUT gauge group and generically leads to tachyonic squark or slepton masses. In the particular case where the GUT gauge group is SU(5), we show that this problem can be solved if there are two independent sectors where SUSY is spontaneously broken or simply by using a solution of the doublet-triplet splitting problem where the vev responsible for the spontaneous breaking of the GUT symmetry is larger than the SUSY breaking scale. In both cases the effects gauge and non-gauge messengers have to combine if a viable spectrum is to be reached. We then finish out study in chapter 6 by considering the semi-direct version of gauge mediation with gauge messengers. As it is known, gaugino masses are screened from messenger interactions, at leading order in the SUSY breaking parameter F. Because of this, gaugino soft masses will be suppressed with respect to scalar soft masses. This leads to a scenario of mildly split SUSY, i.e. scalars are at least one or two orders of magnitude heavier than gauginos. This generically leads to some extra fine-tuning to get the EW breaking scale to occur at the correct scale.

APA, Harvard, Vancouver, ISO, and other styles

22

Lawn, Samuel Oliver. "Invesitagating the role of the guanine nucleotide exchange factor P-Rex1 in cell invasion." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/533/.

Full text

Abstract:

Cell invasion is a critical step in cancer metastasis. Rho family GTPases are key regulators of cell motility, regulating the form and function of the actin cytoskeleton. P-Rex1, a Rac guanine nucleotide exchange factor (GEF), was previously identified in this lab in a transcriptional screen for mediators of cell invasion. A number of GEFs have been shown to regulate the invasive phenotype of tumours and cancer cell lines, leading to the hypothesis that P-Rex1 is an invasion promoting gene. We show that overexpression of P-Rex1 induces dramatic morphological changes in fibroblasts characterised by extensive membrane ruffling and lamellipodia formation. P-Rex1 modulates the 2D migration of fibroblasts and potently stimulates their in vitro invasion. These phenotypes are dependent on Rac1, PI3 kinase and GPCR signalling and can be stimulated by growth factor mediated accumulation of PIP3. P-Rex1 expression is shown to be upregulated in a number of melanoma derived cell lines compared to normal human melanocytes. Ectopic overexpression of P-Rex1 enhances the membrane ruffling and invasion of melanoma derived cell lines, while in some cell lines, limiting its expression by RNAi reduces both serum stimulated ruffling and invasion. The P-Rex1-/- mouse is shown here to have a previously uncharacterised pigmentation phenotype, consistent with a defect in melanocyte precursor migration. This phenotype is not overcome by crossing on to a melanoma model driven by expression of activated N-RasQ61k and loss of the INK4a locus. While it seems that P-Rex1 deficiency does not affect melanoma initiation, studies are ongoing to determine whether it has a role in metastastic progression. Data also suggests that P-Rex1 has an unexpected role in lymphoma development. This work further characterises the regulation and function of P-Rex1, adding to our understanding of how RhoGTPase GEFs function in cancer.

APA, Harvard, Vancouver, ISO, and other styles

23

Gonzalez, Pedro Antonio. "Study of visual field defects in patients with epilepsy receiving Vigabatrin." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/543/.

Full text

Abstract:

Vigabatrin, a GABA (γ-aminobutyric acid) agonist is a drug widely prescribed in Europe and Asia between 1989 and 1997 for drug resistant, partial epilepsy and has been associated with visual field defects. Uncertainity in the effect of Vigabatrin on vision resulted in decreased prescriptions. However, there has been poor reproducibility in previous studies due to many factors, especially poor sensitivity and specificity of tests for Vigabatrin associated visual dysfunction. The wide field multifocal electroretinogram (WF-mfERG) can objectively measure discrete areas of retinal function up to 90 degrees. The results of 204 patients with epilepsy divided into four groups are presented. A subgroup of 89 patients had repeat investigations. The patients were divided into four groups. Group 1.The Vigabatrin group comprised patients who had been taking Vigabatrin for at least 1 year (56 patients). Group 2. Forty nine patients who had previously taken Vigabatrin for at least 1 year but had stopped taking this treatment for at least 2 years comprised the ex-Vigabatrin group. Group 3.The GABA group had 46 patients who used other anti-epileptic drugs (AED) with GABA action other than Vigabatrin. Group 4. Fifty three patients who had never used an AED with GABA action including Vigabatrin made up the non-GABA group. Surprisingly, the percentage of patients with visual field defects were high in all groups investigated (Vigabatrin group 59%, ex-Vigabatrin group 46%, GABA group 30.2% and non-GABA group 21.2%). However, abnormal bilateral WF-mfERG responses were only found in the Vigabatrin group (48%) and the ex-Vigabatrin group (22%). The study suggests that there are probably different causes of visual field abnormalities in patients with epilepsy not related to Vigabatrin. We propose that the most sensitive and specific tests that can be used to detect visual dysfunction associated with Vigabatrin is the WF-mfERG

APA, Harvard, Vancouver, ISO, and other styles

24

Lertchoosakul, Kanokrat. "The rise of the Octobrists : power and conflict among gormer left wing student activists in contemporary Thai politics." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/503/.

Full text

Abstract:

Since the early 1990s, the prominent role of 'Octobrists' – former left wing student activists from the 1970s – has become increasingly evident in parliamentary and extra-parliamentary politics. Some Octobrists have played leading or supporting roles in key moments of political transition, such as the 1992 urban middle-class movement for democracy, various social movements throughout the mid-1990s, the political reform process of the late 1990s, and the rise of the Thais Love Thais (Thai Rak Thai) government under Thaksin Shinawatra in 2001. But over the course of the past ten years, these former student activists have become increasingly divided, amidst the protracted conflict between 'Yellow shirt' (anti-Thaksin) and 'Red Shirt' (pro-Thaksin) forces in Thai politics. Octobrists have defended opposing political stances and severely attacked one another across the political divide. This thesis examines why the Octobrists have managed to remain a significant force in Thai politics, despite the collapse of left wing politics in the late 1970s, and why they have experienced deepening internal divisions and a crisis of legitimacy over the course of the past decade. This thesis argues that the Octobrists successfully exploited shifts in the structure of political opportunities over the 1980s and 1990s which allowed them to overcome constraints on their involvement in politics. These former left wing student activists successfully made use of the political skills, social networks, and progressive language which they had developed and refined since the 1970s, in order to gain access to new channels of political influence and power. Above all, they managed to reframe their earlier history as leftist failures and to craft a new political identity as 'Octobrists', as heroic fighters for democracy and against authoritarian rule in the 1970s. In examining the rise and deepening of conflicts among the Octobrists, moreover, this thesis traces the shifts in political environment which accompanied the ascendancy and entrenchment of the Thaksin government and the rise of antiThaksin mobilisation over the past decade, which undermined the loose unity among Octobrists and created new sources of tension and conflict in their midst. The thesis also shows how the notion of 'Octobrists' shifted from an effective rubric for forging a shared identity among former student activists to a rhetorical device for conflict and contestation among former comrades-in-arms.

APA, Harvard, Vancouver, ISO, and other styles

25

Vanden, Eynde Oliver. "Three essays on political economy and economic development." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/523/.

Full text

Abstract:

This thesis consists of three independent chapters. The ﬁrst chapter examines the strategic choices of the targets and the intensity of violence by rebel groups. The chapter presents a theoretical framework that links a rebel group’s targeting decisions to income shocks. It highlights that this relationship depends on the structure of the rebels’ tax base. The hypotheses from the model are tested in the context of India’s Naxalite conﬂict. The second chapter estimates the impact of military recruitment on human capital accumulation in colonial Punjab. In this context, I ﬁnd that higher military recruitment was associated with increased literacy at the district-religion level. The ﬁnal chapter presents a model that describes the optimal design of civil-military institutions in a setting where some control of the military over domestic politics is deemed desirable.

APA, Harvard, Vancouver, ISO, and other styles

26

Lisicky, Milan. "Essays on the macroeconomic impact of trade and monetary policy." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/533/.

Full text

Abstract:

My thesis consists of three chapters. The aim of the first two chapters is to investigate the linkages between trade and the cross-country comovement and volatility of GDP growth, while the last chapter is an independent study on how the optimal design of monetary policy depends on the share of labour- and capital-intensive sectors. The first chapter develops a framework to study the effects of international trade on GDP comovement. Using a standard trade-theoretical approach, I first show how the comovement between any pair of countries is linked to shocks affecting both the two countries bilaterally and all other countries. Secondly, I use a calibrated version of the model to assess the importance of the bilateral channel relative to the role of linkages with all other countries. The second chapter investigates whether and how openness to trade may affect macroeconomic volatility. While greater openness provides a powerful channel for transmission of foreign disturbances, it also lowers the exposure to domestic shocks. My co-authors and I show that as long as the volatility of trading partners and covariance of shocks across countries are not too large, trade can act as a channel for the diversification of country-specific shocks and in that way contribute to lower volatility. The third chapter examines what is the optimal measure of inflation in a two-sector economy with nominal frictions, where sectors differ in labour intensity. I find that a welfare-oriented central bank should follow more closely the developments in the less labour-intensive sector. The source of this bias is traced back to a greater sensitivity of the marginal product of labour in that sector, so that output dispersion caused by nominal rigidities generates higher efficiency losses where labour is relatively less abundant.

APA, Harvard, Vancouver, ISO, and other styles

27

Asquer, Alberto. "Implementing regulatory reforms in multi-level governance systems : the case of the reform of the water sector in Italy (1994-2006)." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/543/.

Full text

Abstract:

Within the field of regulation policy and politics, various scholarly works have examined policy reforms intended to change the regulation of large-scale infrastructure-based public service industries. Relatively little attention has been placed, however, on the jagged and ineffectual implementation of regulatory reforms that especially takes place when the implementation context includes features of a multi-level governance system. For reasons especially related to the technical, economic, and territorial characteristics of infrastructure and sub-national governments' political responsibilities towards local communities, within this type of scenario the implementation of regulatory reforms tends to exhibit high levels of political confrontation between actors of the reformed infrastructure industry, with respect to what is ordinarily experienced when a regulatory reform is implemented by public agencies or any body of the executive at the central level. This thesis aims to contribute furthering our understanding of the political economy of implementing regulatory reforms by conducting an exploratory case study whose episode is the implementation stage of the 12 year long (1994-2006) policy cycle to liberalise, re-regulate, and privatise Italy’s (drinking water and waste) water sector. The main explanatory issues at stake relate to why the implementation trajectory changed over time (i.e., a period of obstructed implementation was followed by one of accelerated execution of the policy reform content) and across space (i.e., implementation progressed faster in Alto Valdarno in Tuscany than elsewhere in the country). The analysis of the case is conducted by following two alternative theoretical approaches in turn, namely institutional rational choice and institutional processualism. Answers to these questions provide some evidence for qualifying existing generalised arguments about the policy. process of implementing regulatory reforms and for assessing the relative strengths and weaknesses of alternative theoretical perspectives.

APA, Harvard, Vancouver, ISO, and other styles

28

Tacharoen, Kitjawat. "Essays on effects of skill mix on productivity and determinants of foreign ownership in developing countries." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/563/.

Full text

Abstract:

The first chapter is titled "Productivity As If Space Mattered: An Application to Factor Markets Across China”. Optimal production decisions depend on local market characteristics. This chapter develops a model to explain firm labour demand and firm density across regions. Firms vary in their technology to combine imperfectly substitutable worker types, and locate across regions with distinct distributions of workers and wages. Firm technologies which best match regional labour markets explain both productivity differences and firm density. Estimating structural model parameters is simple and relies on a two stage OLS procedure. The first stage estimates local market conditions using firm employment and regional data, while the second incorporates regional costs into production function estimation. The method is applied to Chinese manufacturing, population census and geographic data to estimate local market costs and production technologies. In line with the model, we find that labour markets which provide cost advantages explain substantial differences in firm productivity. Furthermore, regions which have lower optimal hiring costs attract more firms per capita. This is a joint work with Wenya Cheng and Dr John Morrow. The second chapter is called “Foreign Ownership Share and Property Rights: Evidence from Thai Manufacturing Firms”. Existing work based on property-rights theories treat ownership as binary and the degree of integration as exogenous. This chapter proposes a property-rights model where the degree of integration is endogenised and treated as a continuous variable. The model makes two predictions for firm behaviour under vertical integration. Firstly, foreign ownership shares should increase with the significance of foreign investors’ investment. Secondly, the effect of investors’ investment on ownership increases with the elasticity of substitution across product varieties. Both predictions find considerable support in firm-level data from Thailand. The third chapter, “Product Quality and Intra-firm Trade”, presents a partial equilibrium model with product quality differentiation where heterogeneous firms choose whether to vertically integrate their foreign suppliers or outsource input production. Quality is non-verifiable by third parties which causes the well-known hold-up problem. The severity of the problem increases with product quality. The model yields closed form expression for the productivity threshold that assigns firms into different ownership structures. The impact of quality related parameters on the threshold is analysed in detail.

APA, Harvard, Vancouver, ISO, and other styles

29

Grušić, Uglješa. "The international employment contract : ideal, reality and regulatory function of European private international law of employment." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/583/.

Full text

Abstract:

Private international law has traditionally been perceived as a field of law concerned with resolving individual private disputes and achieving private justice and fairness in individual cases. This dissertation challenges this view by examining the systemic function of European private international law of employment, one of allocating and protecting regulatory (i.e. legislative and adjudicatory) authority of states in the field of labour law, thus maintaining and managing the diversity of European national labour law systems and safeguarding the objectives of uniform and harmonised EU employment legislation. This dissertation also explores the changes that the ‘Europeanization’ of private international law of employment has brought about in the traditional rules and perception in this field of law in England. In addition to introducing special rules of jurisdiction in employment matters that had not existed before, the European private international law instruments have largely merged the traditionally perceived contractual, statutory and tortious claims into one type of claim for choice-of-law purposes, thereby also abolishing concurrent causes of action. The conceptualisation of this field of law in terms of its regulatory function reveals something about the nature of private international law as a whole. The fact that European private international law of employment performs a regulatory function is a piece of evidence for the proposition that the division between the ‘private’ and the ‘public’, traditionally perceived as embedded in the foundations of the discipline and even expressed in its very name, has faded away.

APA, Harvard, Vancouver, ISO, and other styles

30

Hinds, Matthew. "Anglo-American relations in Saudi Arabia, 1941-1945 : a study of a trying relationship." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/593/.

Full text

Abstract:

This thesis offers a fresh interpretation of Anglo-American relations in the Kingdom of Saudi Arabia during the period 1941 to 1945. Historians of Anglo-American relations have characterized the bilateral relationship as one of rivalry and polarization. While examples of underlying national competition can be identified wherever the wartime alliance operated, whether on the battlefield or at the conference table, the commonalities which united the allies should, however, be given equal weight. My thesis departs from the traditional historiographical perspective, arguing that when closely examined, the allies were very aware of the strategic reciprocal benefits that would emanate from integrating their policies in Saudi Arabia. First and foremost, Britain and the United States’ relations in Saudi Arabia were shaped by the fact that the two countries were allies working side by side in the global struggle that was the Second World War. In this wartime context, the strategic influence of Saudi Arabia has tended to be overlooked. The Kingdom’s influence resided in its geographic location, its religious centrality within Islam, and most importantly, its rare political status as a sovereign Arab state. These attributes served as a unifying force for British and American wartime interests, encouraging the two allies to strive for an Anglo-American partnership in Saudi Arabia that was built on the concept of strategic interdependence. While collaboration between Britain and the United States ebbed and flowed, it is a testament to their continued pursuit of cooperation that the activities of the wartime alliance in Saudi Arabia between 1941 and 1945 were envisaged by policymakers as a template for achieving greater Anglo-American accord throughout the Middle East during and beyond the Second World War.

APA, Harvard, Vancouver, ISO, and other styles

31

Bleyleben, Nicole. "Beyond the fine print : water sector reform and private sector participation : case study based on La Paz/El Alto PPP concession." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/513/.

Full text

Abstract:

This dissertation sheds new light upon the complex interplay of factors (social, political and economic) that constrain the enabling environment for water sector reform and private sector participation (PSP) by analysing of the process of policy reform and the nature of stakeholder engagement in the provision of water and sanitation. Findings are based on an in depth case study of the La Paz/El Alto concession arrangement from 1997–2005, when the contract was abruptly terminated. The analysis is encompassed within the New Institutional Economics conceptual framework as it provides a holistic application of economic analysis on the role of incentives, institutions and behaviour, providing a common link in understanding between traditional economists and other social scientists, allowing for greater reflection as to the ways socio-political, cultural and historical contexts determine the behaviour of those involved in the water reform process. The delicate nature of the water sector provides evidence of how under certain institutional constraints, and where optimum accumulation of information is virtually impossible, human behaviour can become motivated by a volatile set of preferences, making it particularly difficult for policy-makers to manage the reform process and accurately predict reform outcomes. Research findings conclude that the difficulties policy-makers faced in reforming the water sector and introducing PSP in the case of La Paz/El Alto, stemmed from three fundamental factors: (i) The reform process did not consider how race-based socio-political and economic hierarchies, endemic in Bolivian history and culture, would influence intended outcomes; (ii) stakeholders underestimated the transaction costs involved in the process of reform and PPP implementation due to information and bargaining asymmetries; (iii) systemic barriers, beyond the control of stakeholders involved, constrained the space for partnership innovation and flexibility in the provision of water and sanitation, debilitating the possibilities for future collaboration between civil society, government and the private sector.

APA, Harvard, Vancouver, ISO, and other styles

32

Yazdani, Shahid. "Emergency safeguard : WTO and the feasibility of emergency safeguard measures under the general agreement on trade in services." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/573/.

Full text

Abstract:

The General Agreement on Trade in Services (GATS) along with other agreements was concluded in the Uruguay Round of Multilateral Trade Negotiations in 1994. However, negotiations continued within the WTO framework and are still a work in progress on some specific issues under the GATS including the question of Emergency Safeguard Measures, which has been raised in Article X of the GATS as part of its ‘built-in agenda’. The thesis looks at the concept of the Emergency Safeguards Measures (ESMs) in the GATT/WTO and tries to develop an answer to the ‘question of ESMs’, which is deluding the negotiators and researchers for more than fifteen years. The thesis tries to analyse whether the GATT type ESMs can be transposed to GATS. It also explores that whether ESMs that are modelled on GATT are feasible under GATS, and if feasible, are these really desirable. If these are feasible and desirable then what should be their possible structure remaining within the existing GATT paradigm. The thesis walks through the provisions that already exist in the GATS to meet the circumstances perceived by the countries that are seeking specific ESMs under GATS and whether these provisions address the concerns of the demanders of the concept. The thesis not only takes into account the academic and legal literature on the subject but also and perhaps more practically, takes into account the dynamics of the negotiations, discussions and debates within the WTO system on the subject. The thesis tries to provide an in-depth analysis of the issue and goes beyond what is already available in the International Trade Law literature on the ESMs under the cross border trade in services. It seeks to answer a question that presently exists in the International Trade Law especially with reference to the law emerging out of WTO.

APA, Harvard, Vancouver, ISO, and other styles

33

Almutairi, Humoud. "A comparison between Islamic and conventional home financing in Kuwait : client perceptions of the facilites offered by the National Bank of Kuwait and Kuwait Finance House." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/543/.

Full text

Abstract:

This study determines the awareness of the Islamic home inance products compared with conventional home financing, as well as clients’ perceptions of home financing, with the National Bank of Kuwait represented as a traditional Bank and the Kuwait Finance House as an example of an Islamic Bank. This comparison is important since it is new in this area and ives the clients an overview about available home finance. In addition, new students can benefit from this study to build on and start from where I finished. The empirical research was conducted utilizing both quantitative and qualitative methods, as well as a case study and interviews, which is a method known as the triangulation technique. Questionnaires were distributed to 200 clients who had applied for home financing from both banks, using 100 clients from each bank. To sum up, it can be argued that an examination of Islamic banking as symbolized by the Kuwait Finance House has revealed that this type of financial institution has experienced a boom and has been successful in establishing itself as a practical substitute to conventional banking, in spite of what have been seen as authoritarian and nonflexible rules and regulations governing the activities of this type of financial institution. Islamic banks have experienced a boom and have been successful in developing alternative methods for attracting and utilizing funds in money-making outlets, regardless of the fact that they are comparative beginners in the field. Future prospects for the banks are even more promising, as experience is likely to improve the capability of these institutions to compete and to improve their performance.

APA, Harvard, Vancouver, ISO, and other styles

34

Albaaly, Emad Ahmed Mohamed Solima. "The impact of the interactive whiteboard on medical school students' ESL essay writing." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/563/.

Full text

Abstract:

This study aimed to investigate the impact of the interactive whiteboard (IWB) on the Egyptian medical school students’ ESL (English as a Second Language) essay writing and attitudes towards writing. The study clarified the evidence regarding Egyptian medical students’ relative weakness in writing as compared to the other language skills. It therefore investigated the general areas of writing, and identified the writing skills essential for the medical students, and designed a module based on these identified skills. An experimental design was adopted. The sample was composed of sixty students randomly selected and later divided into two separate groups: one intervention group which was taught by the IWB and a control group by the traditional method which involved teaching with a pen and paper, and a whiteboard. Four instruments were used: 1) a writing micro-skill questionnaire investigating specialists’ views on the skills important to the medical students; 2) a writing test assessing students’ achievement in ESL essay writing; 3) a writing attitude survey assessing students’ views about writing before and after both methods were used. These instruments were applied to both groups, as well as an additional IWB Attitude survey assessing students’ views about the IWB before and after the intervention for the intervention group. Results reveal that twenty nine writing skills were required by students, according to the specialists’ views and, more importantly, the IWB had no positive impact on the Egyptian students’ attainment in ESL essay writing (a non- significant effect size of -0.18). By contrast, it is revealed that the IWB had a positive impact on students’ attitudes towards both writing (effect size of 1.88) and towards the board itself.

APA, Harvard, Vancouver, ISO, and other styles

35

Schutte, Barend-Christiaan. "Images of a new German identity : the portrayal of the unification process in documentary and feature films since 1990." Thesis, Southampton Solent University, 2005. http://ssudl.solent.ac.uk/593/.

Full text

Abstract:

German unification is frequently seen as an event and a date October 3, 1990 - on which a divided people could finally live as one, restored to a natural state of togetherness. Within Germany, however, the experience since 1990 has been one of realisation of deep inner division, and recognition that unification is in fact a long term process, and perhaps even an uncertain goal in Europe, where, everywhere else, new regional consciousnesses are questioning old national identities. Since the future role of Germany in Europe is a major and controversial issue in economic, political and cultural circles, the critical construction of realistic and authentic portrayals of post-unification Germany is of considerable importance. The concept, size and location of a 'German nation' have been contested and fought over from outside and within since its 19th century forging under the leadership of Bismarck, but if one proceeds on today's dominant assumption that between 1949 and 1989 the German people existed as one nation, though they were separated by one of the most tightly guarded borders in world history - a border that separated more than just two countries, but rather served as the confrontational line between two superpowers with opposing ideological, economic and political systems - one can come to the logical conclusion that German unification in 1990 was merely an event which enabled 'the German Nation' to live in the same, unified country once again. However, if one recognizes the fact that 40 years of separation superimposed on more complex historical and contemporary mappings inevitably led to the development of two distinct collective identities, it becomes clear that German unification was - and still is - in fact an on going process of attempting to merge the peoples of two states into one, or one into the other. This is a process that will reach deep into the 21st century, involving the development of a new German national identy within the European Union in a rapidly changing world. This thesis does not try to speculate on or define a 'general' or 'essentialist' sense of what the new German national identity might be. It rather analyses texts of a selection of Germany's image makers since 1990, and examines critically a range of constructions of the new identity from documentaries and docudramas to feature films. The project does not ask to be judged as a contribution to film studies in the narrow sense of that term, seeing itself instead as an interdisciplinary undertaking which derives its insights from a fruitful mix of approaches used in Critical Discourse, Analysis, History, Cultural Studies and Film Studies. Just as it may be said that the German Democratic Republic to some extent talked itself out of existence through its people's acceptance of Western discourse, and images of a Western consumer paradise, so it is now worth analysing how the new Germany is, in complex and sometimes contradictory and sceptical ways, attempting to talk itself into existence through discourse and imagery. The thesis examines whether and how, through the medium of film, opinion formers and creative minds, with their various agendas are seeking to influence public perceptions of the post-1990 confrontation between idealised projections of German identity and recalcitrant reality.

APA, Harvard, Vancouver, ISO, and other styles

36

Cook, Glenda. "Life as a care home resident in later years : "living with care" or "existing in care"." Thesis, Northumbria University, 2007. http://nrl.northumbria.ac.uk/533/.

Full text

Abstract:

Despite a widely accepted view of the importance of understanding experience from the point of view of the individual using services in modern western society, there are relatively few studies that have explored day-to-day living in a care home from the older person's perspective. This study aimed to present the voice of the untold stories of care home residents through an interpretative study that was informed by a biographical approach and narrative method. Eight older people who lived in four different care homes in England participated in a sequence of up to eight narrative interviews over a six month period. Through the process of listening to, retelling and interpreting the residents' stories the resident world was explored. There were three stages to the interpretative process that focused on:- developing a naïve or surface understanding to acquire a sense of the whole sequence of a participant's interviews; a structural analysis that examined the interviews to investigate what the text said and how it was said; and a critical in-depth examination of the interpretation within the wider social context. The interpretation revealed the unique way that each participant lived in a care home. These older people worked hard to reconstruct their life following the move to a care home and as they lived there. Though the residents were limited by physical, functional and cognitive problems, they developed strategies with the aim of influencing the life that they lived within a care home. Where they were able to implement those strategies they reconstructed their life in ways whereby they 'lived with care.' In this sense they were active biographical agents shaping this phase of their life. This is an alternative biography, to that of older people 'existing in care' as an outcome of care received. This thesis provides new insights into the residents' world. The overriding conclusion that can be drawn from these stories is that these older people were trying to live as active biographical agents who were instrumental in shaping their own life. They were able to do this to a greater or lesser extent and the conceptual model of biographical living that has been developed from the resident stories provides a framework to depict the complex interactions that shape an individual's experience in this environment. An inherent feature of this model is recognition that residents can be active agents throughout their lives in care homes. In summary, residents' desire to 'live with care' and this is not only possible, it is achievable.

APA, Harvard, Vancouver, ISO, and other styles

37

Mazzoni, Maurizio. "Studio del comportamento elastico di molle a lamina per cartuccia di sospensione motociclistica." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/523/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Pigliapoco, Nicola. "Analisi preliminare per la razionalizzazione dei consumi energetici e studio sulla produzione di energia da fonti rinnovabili nel comparto SAPIR." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/533/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Faccioli, Sara. "Implementazione di metodi per l'analisi frattale di immagini in ambiente CUDA." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/513/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Bedigan, Kirsten Madeleine. "Boeotian Kabeiric ware the significance of the ceramic offerings at the Theban Kabeirion in Boeotia /." Connect to e-thesis, 2008. http://theses.gla.ac.uk/503/.

Full text

Abstract:

Thesis (Ph.D.) -- University of Glasgow, 2008.
Ph.D. thesis submitted to the Department of Archaeology, Faculty of Arts, University of Glasgow, 2008. Includes bibliographical references. Print version also available.

APA, Harvard, Vancouver, ISO, and other styles

41

Martin, Suarez Sofia <1974&gt. "La chirurgia conservativa della valvola aortica." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/503/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Trebbi, Bruno <1977&gt. "Theoretical study of biological systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/513/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Ricci, Francesca <1978&gt. "Baclofen e D-cicloserina come potenziali strumenti terapeutici nella dipendenza da sostanze: studi preclinici nel ratto." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/533/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Cossu, Elena <1976&gt. "Sostenibilità dello spazio urbano e gestione dei rifiuti." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/553/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Baraldi, Matteo <1971&gt. "L'industria delle ombre: la short story fantastica nell'Australia degli anni '70." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/563/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Poerio, Alba <1977&gt. "Study of the antioxidant fraction in edible olive oils obtained from different technological systems and parameters." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/573/.

Full text

Abstract:

Questo lavoro di tesi è stato suddiviso in tre parti. L’argomento principale è stato lo “Studio della componente antiossidante di oli ottenuti da olive mediante l’utilizzo di diversi sistemi e parametri tecnologici”. E’ ben noto come la qualità ossidativa di un olio di oliva dipenda oltre che dalla sua composizione in acidi grassi, dalla presenza di composti caratterizzati da un elevata attività antiossidante, ovvero le sostanze fenoliche. I composti fenolici contribuiscono quindi in maniera preponderante alla shelf life dell’olio extravergine di oliva. Inoltre sono state riscontrate delle forti correlazione tra alcune di queste sostanze e gli attributi sensoriali positivi di amaro e piccante. E’ poi da sottolineare come il potere antiossidante dei composti fenolici degli oli vergini di oliva, sia stato negli ultimi anni oggetto di considerevole interesse, poiché correlato alla protezione da alcune patologie come ad esempio quelle vascolari, degenerative e tumorali. Il contenuto delle sostanze fenoliche negli oli di oliva dipende da diversi fattori: cultivar, metodo di coltivazione, grado di maturazione delle olive e ovviamente dalle operazioni tecnologiche poiché possono variare il quantitativo di questi composti estratto. Alla luce di quanto appena detto abbiamo valutato l’influenza dei fattori agronomici (metodi di agricoltura biologica, integrata e convenzionale) e tecnologici (riduzione della temperatura della materia prima, aggiunta di coadiuvanti in fase di frangitura e di gramolatura, confronto tra tre oli extravergini di oliva ottenuti mediante diversi sistemi tecnologici) sul contenuto in composti fenolici di oli edibili ottenuti da olive (paper 1-3-4). Oltre alle sostanze fenoliche, negli oli di oliva sono presenti altri composti caratterizzati da proprietà chimiche e nutrizionali, tra questi vi sono i fitosteroli, ovvero gli steroli tipici del mondo vegetale, che rappresentano la frazione dell’insaponificabile quantitativamente più importante dopo gli idrocarburi. La composizione quali-quantitativa degli steroli di un olio di oliva è una delle caratteristiche analitiche più importanti nella valutazione della sua genuinità; infatti la frazione sterolica è significativamente diversa in funzione dell’origine botanica e perciò viene utilizzata per distinguere tra di loro gli oli e le loro miscele. Il principale sterolo nell’olio di oliva è il β- sitosterolo, la presenza di questo composto in quantità inferiore al 90% è un indice approssimativo dell’aggiunta di un qualsiasi altro olio. Il β-sitosterolo è una sostanza importante dal punto di vista della salute, poiché si oppone all’assorbimento del colesterolo. Mentre in letteratura si trovano numerosi lavori relativi al potere antiossidante di una serie di composti presenti nell’olio vergine di oliva (i già citati polifenoli, ma anche carotenoidi e tocoferoli) e ricerche che dimostrano invece come altri composti possano promuovere l’ossidazione dei lipidi, per quanto riguarda il potere antiossidante degli steroli e dei 4- metilsteroli, vi sono ancora poche informazioni. Per questo è stata da noi valutata la composizione sterolica in oli extravergini di oliva ottenuti con diverse tecnologie di estrazione e l’influenza di questa sostanza sulla loro stabilità ossidativa (paper 2). E’ stato recentemente riportato in letteratura come lipidi cellulari evidenziati attraverso la spettroscopia di risonanza nucleare magnetica (NMR) rivestano una importanza strategica da un punto di vista funzionale e metabolico. Questi lipidi, da un lato un lato sono stati associati allo sviluppo di cellule neoplastiche maligne e alla morte cellulare, dall’altro sono risultati anche messaggeri di processi benigni quali l’attivazione e la proliferazione di un normale processo di crescita cellulare. Nell’ambito di questa ricerca è nata una collaborazione tra il Dipartimento di Biochimica “G. Moruzzi” ed il Dipartimento di Scienze degli Alimenti dell’Università di Bologna. Infatti, il gruppo di lipochimica del Dipartimento di Scienze degli Alimenti, a cui fa capo il Prof. Giovanni Lercker, da sempre si occupa dello studio delle frazioni lipidiche, mediante le principali tecniche cromatografiche. L’obiettivo di questa collaborazione è stato quello di caratterizzare la componente lipidica totale estratta dai tessuti renali umani sani e neoplastici, mediante l’utilizzo combinato di diverse tecniche analitiche: la risonanza magnetica nucleare (1H e 13C RMN), la cromatografia su strato sottile (TLC), la cromatografia liquida ad alta prestazione (HPLC) e la gas cromatografia (GC) (paper 5-6-7)

APA, Harvard, Vancouver, ISO, and other styles

47

Isabella, Giovanni <1974&gt. "Modelli di regalità nell'età di Ottone I." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/583/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Caruso, Annalisa <1978&gt. "Il finanziamento a titolo di capitale di debito e il rapporto banca impresa: un'indagine sulle micro e piccole-medie imprese italiane." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/593/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Lofiego, Carla <1975&gt. "Il "ritardo evitabile" nella diagnosi di sindrome aortica acuta: analisi dei determinanti clinici e possibili ripercussioni sull'outcome." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/523/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Sivilia, Sandra <1975&gt. "Nerve growth factor in modelli di patologie sperimentali e spontanee." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/543/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic '5o3'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles