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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Low oxidation states of some transition metal complexes

Das, P. K. January 1968 (has links)
No description available.
472

Studies of metal ion carboxylate complexes

Maclean, J. N. January 1964 (has links)
No description available.
473

The (Ab)use of Politics and Eroticism in the Culture of the Spanish Transition to Democracy (1975-1982)

Gil, Wenceslao 01 January 2011 (has links)
This dissertation analyzes the (ab)use of politics and eroticism within the framework of the Transition to democracy in Spain, its social and cultural impact—on literature, film, music, and popular media—, and its consequences. After a period of nearly four decades, when the country was subjected to a totalitarian regime, Spanish society underwent a process of democratic restoration. As a result, the two topics considered taboo during almost forty years of repression—i.e., politics and sexuality/eroticism—, gushed out fiercely. Every aspect of culture was influenced by and intrinsically linked to them. However, while we have been offered a more or less global approach to the Transition—the Transition as a whole—, and some studies have focused on diverse areas, no research to date has covered in depth the significance of those issues during that historical moment. Considering the facts stated above, it was imperative to conduct a more detailed analysis of the influence of both eroticism and politics on the cultural production of the Transition from different perspectives. Although the academic intelligentsia has often rejected them as expressions of mass culture, we must consider Pierre Bourdieu’s theories—in line with the tradition of classical sociology, that includes science, law, and religion, together with artistic activities—, Michel Foucault’s ideas on sexuality, and New Historicism, examining texts and their contexts. This work concludes that the (ab)use of both subjects during the Spanish Transition was a reaction to a repressive condition. It led to extremes, to societal transgression and, in most cases, to the objectification of women because of the impositions of a patriarchal society. It was, however, part of a learning and, in a sense, cathartic process that led, eventually, to the reestablishment of the status quo, to a more equitable and multicultural society where men, women, and any political or sexual tendencies are respected—at least, in theory.
474

Competition at the feed bunk during transition changes the feeding, standing and social behaviour of Holstein dairy cows

Proudfoot, Kathryn Louise 11 1900 (has links)
Transition dairy cows are vulnerable to negative consequences of depressed feed intake due to a transient state of negative energy balance that predisposes them to disease after calving. Competition has been identified as one factor that can decrease feeding activity in mid-lactation cows, but the effects of competition on the transition cow are less well understood. The objective of this study was to test the effect of a competition on the behaviour and feed intake of transition cows. Standing behaviour, feeding behaviour and dry matter intake (DMI) was monitored from 1 wk before to 2 wk after calving for 110 Holstein dairy cows. Social behaviour was recorded in the week before calving. Cows were assigned to a competitive (2:1 cows:bin) or non-competitive (1:1 cow:bin) treatment at the start of the study. Treatment groups were balanced for parity and baseline feeding data, resulting in 8 primiparous and 10 multiparous cows per treatment. Competition dramatically increased the number of agonistic behaviours between cows at the feeder. Primiparous cows showed no change in either feeding or standing behaviour when fed in a competitive environment; however, they increased their total meal duration and within-meal intervals in the wk -1 before and wk +1 after calving. In wk -1 before calving, competitively fed multiparous cows increased the frequency of visits to the feeder but consumed less feed at each visit, resulting in decreased daily DMI. Throughout the experiment, multiparous cows fed competitively spent less time eating at each visit and ate at a faster rate, particularly during the 2 wk after calving. Multiparous cows on the competitive treatment also increased the time they spent standing (without eating) compared to cows on the non-competitive treatment. Feeding rate was negatively correlated with social status in multiparous cows. In summary, the results of this study indicate that restricting access to the feeder increases agonistic behaviours regardless of parity, and cows of different parity and social status respond differently in terms of feeding and standing behaviour. / Land and Food Systems, Faculty of / Graduate
475

Recent advances in asymmetric catalysis

Allen, Joanne Victoria January 1995 (has links)
CHAPTER ONE reviews the literature, discussing aspects of transition metal mediated asymmetric catalysis in the presence of enantiomerically pure ligands. CHAPTER TWO discusses the asymmetric addition of dialkyl-zinc reagents to aromatic aldehydes. The work presented is particularly concerned with the design and construction of enantiomerically pure oxazoline ligands tethered to alcohols These ligands have proved effective in the acceleration of the alkylation reaction and are able to influence good levels of asymmetric induction in the resultant secondary alcohol products CHAPTER THREE examines the electronic (and steric) effects of enantiomerically pure oxazoline ligands for the palladium catalysed allylic substitution reaction. Using ligands possessing two electronically different donor atoms, it is possible to create electronic distortion upon the intermediate allyl complex. In doing so it is possible to direct nucleophilic addition to one carbon centre preferentially to the other, resulting in asymmetric induction. Manipulation of these ligands enables control in the extent of electron distortion inflicted upon the allyl complex and consequently influences the levels of enantioselectivity observed. CHAPTER FOUR investigates the ability of hydrolytic enzymes to kinetically resolve a series of allylic acetates, under varying conditions. Lipases appeared superior to esterases for the substrates employed. In particular cis-3-acetoxy-5-carbomethoxycyclohexene was smoothly resolved m high yield and enantioselectivity. CHAPTER FIVE reports on the potentiality of a dynamic resolution of allylic acetates, using hydrolytic enzymes in the presence of a palladium catalyst. A proposed mechanism is discussed. Initial results are promising, however, the sensitivity of the reaction is realised and optimisation of conditions still needs to be addressed.
476

Impact of the Transition from Pediatric to Adult Medical Care on Health Service Utilization in Inflammatory Bowel Disease (IBD)

Zhao, Xinbei January 2017 (has links)
OBJECTIVES: Inflammatory bowel disease (IBD) is a chronic condition with increasing pediatric incidence. Transition from pediatric to adult care is associated both with disruption of links with familiar caregivers and differences in health care delivery. This study explored the impact of the transfer from pediatric to adult care on health services utilization for pediatric-onset IBD patients. APPROACH: A population-based retrospective cohort study identified all children diagnosed with IBD 1994-2008 and treated by pediatric gastroenterologists from within Ontario health administrative data. Self-controlled case series analyses compared health services utilization in the 2 years before and after transfer to adult gastroenterologists, with a 6-month washout period at transfer. Outcome evaluated included IBD related/specific hospitalization, emergency department (ED) utilization, outpatient visits, and laboratory utilization. Relative incidence (RI) in the post-transfer was compared to pre-transfer periods using Poisson regression analysis controlling for transfer starting age. Analyses were stratified by IBD types: Crohn’s disease (CD) and ulcerative colitis (UC). RESULTS: 536 patients were included in the study (388 CD, 148 UC). ED utilization rate was higher after transfer for both CD (RI 2.12, 95% CI 1.53-2.93) and UC (RI 2.34, 95% CI 1.09-5.03). Other increases in health care provision included outpatients visits (CD: RI 1.56, 95% CI 1.42-1.72; UC: RI 1.48, 95% CI 1.24-1.76), and laboratory investigations (CD: RI 1.43, 95% CI 1.26-1.63; UC: 1.38, 95% CI 1.13-1.68). There was no statistically significant change in hospitalization (CD: RI 0.70, 95% CI 0.42-1.18; UC: RI 2.41, 95% CI 0.62-9.40). Sensitivity analysis revealed similar results when only the first year post-transfer period was assessed. CONCLUSIONS: In the largest study to date examining the transfer from pediatric to adult IBD care, health services utilization increased significantly in the two years after transfer for measures of access to health care providers. Understanding causation and rigorously evaluated transition programs may help to better manage the resources and meet the needs of pediatric-onset IBD patients.
477

Motifs de régulation et dynamique de la voie Mitogen Activated Protein Kinase lors de la transition G2/M des ovocytes de Xénope / Regulation motifs and dynamic of Mitogen Actived Protein Kinase cascade during Xenopus laevis oocytes G2/M transition

Beaujois, Rémy 17 December 2010 (has links)
Lors de la transition G2/M des ovocytes de Xénope, la voie p39Mos-MEK1-MAPK présente des propriétés dynamiques et physiques particulières telles que l’ultrasensibilité, la bistabilité, l’irréversibilité et un caractère ‘tout-ou-rien’. Ces propriétés sont considérées dans le contexte de la boucle de rétroaction positive qui existe au sein de cette voie. L’objectif de cette thèse s’est focalisé sur le rôle de l’oncoprotéine p39Mos et le recrutement des motifs de régulation qui permettent l’apparition de ces propriétés. Des approches expérimentales et in silico ont été menées pour réaliser une modélisation physiquement et biologiquement réaliste de ce réseau. Le modèle développé tient compte de l’influence du MPF sur l’accumulation de p39Mos et ajuste le rôle de la boucle de rétrocontrôle positif. Par ailleurs, nous avons pu mettre en évidence que p90Rsk, cible des MAPK, est dégradée. La voie MAPK a été activée en absence de p39Mos. Nos résultats montrent que la 1,10 Phénanthroline monohydrate (1,10-PA) active les MAPK suivant une réponse graduelle et ultrasensible. L’action de la 1,10-PA s’exerce en absence de synthèse protéique et de toute boucle de rétrocontrôle, et nous avons émis l’hypothèse que la 1,10 PA agit via l’inactivation d’une MEK-phosphatase. Dans ce contexte, un modèle de pro-action est discuté et des inhibiteurs de phosphatases ont été utilisés pour activer les MAPK en absence de p39Mos. Nos résultats discutent du rôle de la boucle de rétroaction positive dans l’activation des MAPK et montrent que l’ultrasensibilité de réponse des MAPK peut être générée par des motifs de régulation de type pro-action. / During G2/M transition in Xenopus oocyte, p39Mos-MEK1-MAPK cascacade harbors specific dynamic and physical properties, such as ultrasensitivity, bistability, irreversibility, and all-or-none responses. These properties are generally considered in the context of the positive feedback loop that embeds the p39Mos-MEK1-MAPK pathway architecture. The objective of this work was focused onto p39Mos oncoprotein and regulation motifs recruitment enabling together the generation of such properties. Both experimental and in silico approaches were undertaken in order to yield a realistic modelisation, physically and biologically relevant for this network. We developed a model that takes into account the influence of MPF onto p39Mos accumulation, and adjusts the role of the positive feedback loop. Also, we were able to show that p90Rsk, target of MAPK, was degraded. This signaling pathway was activated in the absence of p39Mos. Our results show that 1,10 Phénanthroline monohydrate (1,10-PA) is able to induce gradual and ultrasensitive MAPK activation. 1,10-PA action is then exerted in the absence of protein synthesis and positive feedback loop. In this context, a feed forward loop model can be considered, and phosphatase inhibitors were used for MAPK activation in the absence of p39Mos. Our results confront the role attributed to the positive feedback loop in MAPK activation, and show that this ultrasensitive response may be generated in vivo through feed forward regulation motifs.
478

Nitrosyl hydrides and cations of Group VI transition metals

Oxley, Jimmie Carol January 1983 (has links)
The novel bimetallic hydrides [(n⁵-C₅H₅)W(N0)IH]₂ and [(n⁵-C₅H₅)W(N0)H₂]₂ can be prepared sequentially by the metathesis of [(n⁵-C₅H₅)W(N0)IH₂]₂ with Na[H₂Al(0CH₂CH₂0CH₃)₂]. Analyses of the ¹H NMR spectra of C[(n⁵-C₅H₅)W(N0)IH]₂ and [(n⁵-C₅H₅)W(N0)IH₂]₂ show the former contains hydride ligands bound to tungsten in a terminal fashion, while the latter possesses two terminal and two bridging hydrides. Addition of a Lewis base to [(n⁵-C₅H₅)W(N0)IH]₂ results in the formation of hydride species (n⁵-C₅H₅)W(N0)IHL (L = P(0Ph)₃, P(0Me)₃, PPh₃); in like manner, the dimer [(n⁵-C₅H₅)W(N0)IH₂]₂ is cleaved by triphenylphosphite to form the monomer cis or trans [(n⁵-C₅H₅)W(N0)IH₂[P(0Ph)₃]. A comparison is made of the reactivity of the tungsten-hydrogen link in the nitrosyl hydrides (n⁵-C₅H₅)- W(N0)IH[P(0Ph)₃], (n⁵-C₅H₅)W(N0)₂H, and (n⁵-C₅H₅)W(N0)IH₂[P(0Ph)₃]. The Mo(N0)₂²⁺ unit is obtained as the tetrakis-solvate via chloride abstraction from Mo(N0)₂Cl₂ by AgBF₄ or nitrosylation of Mo(C0)₆ by NOPF₆ in coordinating solvents such as nitromethane, acetonitrile, or tetrahydro-furan. The unsolvated complex [Mo(N0)₂(PF₆)₂][aub=n] is produced if the latter reaction is performed in dichloromethane; however, it readily converts to [Mo(N0)₂S₄](PF₆)₂ upon exposure to coordinating solvents (S). Hard Lewis bases (L = CH₃CN , 0PPh₃ or L₂ = 2 ,2-bipyridine replace the solvent molecules in [Mo(N0)₂S₄]X₂ (X = BF₄⁻, PF₆⁻) forming complexes [Mo(N0)₂L₄]²⁺ or [Mo(N0)₂L₂S₂]²⁺ depending upon the solvent employed. Reagents capable of being oxidized appear to reduce the dinitrosyl dication without permanent coordination to the molybdenum centre. Reduction of [Mo(NO)₂S₄](PF₆)₂ or [Mo(N0)₂(PF₆)₂][sub=b] is effected by sodium amalgam (one equivalent); addition of a ligand L₂ (L₂ = 2,2-bipyridyl, 3,4,7,8-tetramethyl-1,1O-phenanthroline) to the reaction mixture permits the isolation of [M(NO)₂L₂]₂(PF₆)₂. Addition of excess ligand results in the formation of non-nitrosyl containing species [Mp(L₂)₃]PF₆ (L = 0PPh₃ or L₂ = 3,4,7,8-tetramethyl-1 ,10-phenanthro- line). Decomposition of the nitrosyl species results from attempts to reduce [Mo(NO)₂S₄]²⁺ by two electrons. New complexes are identified by the aid of IR and ¹H, ¹⁹F, or ³¹P NMR spectroscopy and conductance measurements. Attempts to prepare thionitrosyl analogues of [Mo(N0)₂L₄]²⁺ have met with limited success; the only wel1-characterized thionitrosyls isolated in this study are the known (n⁵-C₅H₅)Cr(C0)₂NS and the new [(n⁵-C₅H₅)Mo-(N0)(NS)PPh₃]BF₄. Also discussed is the interaction of NOPF₆ with solvents. NOPF₆ has been found to react slowly with acetonitrile, a common solvent for nitro-sonium salts. / Science, Faculty of / Chemistry, Department of / Graduate
479

Transpace : an architectural intervention for people in transition

Meiring, Christina Isabella 25 July 2008 (has links)
Identity, belonging and being are some of the aspects inventively explored in this document. In times of fundamental change, people tend to find a space, lose it and then find another space as life and the world transform around them. What does this metamorphosis entail and in what ways are we affected by it? How do we live through it and what may we become on our journey towards each other, particularly when the space and places from which we depart are – at least on the surface – so vastly different? Within our voyages of transitional discovery, we too often repudiate the underlying structure from which our values, norms and standards are born – the configuration of beliefs that, when being threatened, results in conflict, bringing forth anger and dispute. The proposed discourse initiates another way of being by concretizing phenomenological philosopher Martin Heidegger’s notion of dwelling. It furthermore explores the contributions made by American architect Christopher Alexander, indicating important ways in which Heidegger’s dwelling can be translated into more grounded architectural meaning. Within the urban context, the design addresses these fundamental structures of being and the predicaments experienced between people and place. / Dissertation (MArch(Prof))--University of Pretoria, 2008. / Architecture / unrestricted
480

Accaparement de l'état et affaiblissement de la légitimité étatique : failles du processus transitionnel russe

Szyjan, Clara Jennifer Rachel January 2005 (has links)
No description available.

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