• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 506
  • 117
  • 68
  • 54
  • 36
  • 31
  • 19
  • 10
  • 10
  • 8
  • 7
  • 5
  • 4
  • 4
  • 4
  • Tagged with
  • 1043
  • 83
  • 79
  • 73
  • 68
  • 63
  • 58
  • 56
  • 50
  • 49
  • 49
  • 48
  • 48
  • 46
  • 45
  • 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.
181

Segment Definition for Financial Reporting by Diversified Firms

Bostrom, Donald E. 05 1900 (has links)
Both revenues and earnings of diversified firms are increasingly being reported, to the government and the public, on a subentity basis. Adequate criterial foundations do not exist to permit the effective general prescription of specific segment delineations, nor is it known whether such criterial assists can be usefully developed.Demands for segmentation in financial reports are currently intense. Actual reporting practices are largely nonstandardized as to either the definition of segments employed or, the disclosure modes used to present them. Neither conceptual nor theoretical supports are now adequate in guidance to the forms and levels of segmentation activity now required. Prerequisite to effective development of such supports is an-adequate understanding of the corporate diversification phenomenon itself. This dissertation project investigates and analyzes the nature of corporate diversification, as manifested in (1) its historical evolution; (2) general comprehensions of the phenomenon, as evidenced in published opinions and conceptual reasoning schemes of both authoritative experts and lay investors; and (3) formal research by others. Additionally, the results of these investigations and analyses are developed into conceptual schemes and theoretical frameworks, at moderate levels of abstraction.
182

Oxygen-Sensitive Luminophores: A Survey of the Literature and Efforts toward a Novel Porphyrin-Pillared Zirconium Phosphonate

Wright, Joseph 01 January 2016 (has links)
Measurement and mapping of the pressure distribution across the surface of a suitably scaled model is an integral step in the design of any aircraft or automobile. For this purpose, the traditional workhorses of the aeronautic and automotive industries have been pressure taps--small orifices that contain electronic pressure transducers. Unfortunately, in addition to the limited spatial resolution achievable with such devices, their technical complexity and cost constitute serious disadvantages. For more than 35 years, researchers have pursued a fundamentally different alternative: indirect measurement of pressure via oxygen-induced quenching of the luminescence emitted by certain chemical species. Porphyrin complexes of dipositive palladium and especially platinum have emerged as one of the principal classes of oxygen-sensitive luminophores; ruthenium(II) polypyridyl complexes comprise another. Various other metals also form luminescent coordination complexes that are susceptible to quenching by O2, however, and these too have contributed to the diversity of luminophores that are now available for incorporation into pressure-sensitive paints and related films and coatings. After treating the photophysics of luminescence quenching by molecular oxygen and quantitative descriptions of this phenomenon in the ideal case and in heterogeneous media, the thesis presents a comprehensive survey of the chemical literature on oxygen-sensitive luminophores. Efforts to prepare and characterize a novel porphyrin-pillared mixed zirconium phosphonate are then detailed. Following complexation of Pt(II) ions by the porphyrin moieties, this material is expected to display oxygen-sensitive luminescence and should ameliorate such difficulties as luminophore aggregation and matrix photodegradation that are associated with many existing pressure-responsive coatings. Its preparation necessitated preliminary formation of a porphyrin functionalized with two phenylphosphonic acid groups, which was obtained by synthesizing dipyrromethane and diethyl 4-formylphenylphosphonate and condensing these two precursors. The mixed phosphonate, a layered material assembled from ZrOCl2 · 8H2O, methylphosphonic acid, and the aforementioned porphyrin, was then prepared in refluxing HF. Solid-state 31P NMR spectra and powder X-ray diffraction patterns were acquired for the final product, its estimated interlayer spacing of 22.8 Å figuring prominently in analysis and discussion of the X-ray data.
183

Hydrogen Sulfide as an allosteric modulator of ATP sensitive potassium channels in colonic inflammation.

Gade, Aravind 18 April 2012 (has links)
The ATP sensitive potassium channel (KATP) in mouse colonic smooth muscle cell is a complex containing a pore forming subunit (Kir6.1) and a sulfonyl urea receptor subunit (SUR2B). These channels are responsible for maintaining the cellular excitability of the smooth muscle cell which in turn regulates the motility patterns in the colon. We used whole-cell voltage-clamp techniques to study the alterations in these channels in smooth muscle cells in experimental model of colitis (colonic inflammation). Colitis was induced in BALB/C mice following an intracolonic administration of trinitrobenzene sulfonic acid (TNBS). KATP currents were measured at Vh -60 mV in high K+ external solution. The dose-response to levcromakalim (LEVC), a KATP channel opener, was significantly shifted to the left in the inflamed smooth muscle cells. Both the affinity and maximal currents induced by LEV were enhanced in inflammation. The EC50 in control was 6259 nM (n=10) and 422 nM (n=8) in inflamed colon while the maximal currents were 9.9 ± 0.71 pA/pF (60 μM) in control and 39.7 ± 8.8 pA/pF (3 μM) following inflammation. Similar to LEVC, KATP currents activated by sodium hydrogen sulfide (NaHS) (10-1000 μM) were significantly greater in inflamed compared to controls. In control cells, pretreatment with 100 µM NaHS shifted the EC50 for LEV-induced currents from 2838 nM (n=6) to 154 nM (n=8). These data suggest that NaHS can act as an allosteric modulator for LEV-induced KATP currents. Decreased colonic motility may result from enhanced KATP activation by increased release of H2S in colitis.
184

Localisation d'un locus pour trait quantitatif pour l'hypertension sur le chromosome 18 du rat Dahl

Lambert, Raphaëlle January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
185

Identification of blood pressure genes in the Dahl salt-sensitive hypertension model

Dutil, Julie January 2005 (has links)
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.
186

Identification des mutations responsables de la NHSA2 et de l'AOA2 dans la population canadienne-française : deux nouveaux exemples de maladies à effet fondateur au Québec

Roddier, Katel January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
187

Mobilité quotidienne, socialisation et ségrégation : une analyse à partir des manières d'habiter des adolescents de zones urbaines sensibles / Daily mobility, socialisation and segregation : The ways of living diversity of the adolescents of sensitive urban zones

Oppenchaim, Nicolas 23 November 2011 (has links)
L'objectif de cette thèse est de mieux documenter les différentes manières d'habiter des adolescents de zones urbaines sensibles (ZUS) franciliennes en prenant appui sur l'analyse de leurs pratiques de mobilité quotidienne. Elle vise à répondre aux trois questions suivantes :-les adolescents de ZUS ont-ils une mobilité spécifique par rapport aux autres adolescents ? -la diversité géographique des ZUS et l'hétérogénéité sociale des adolescents de ces quartiers se traduisent-elles par des pratiques de mobilité différenciée et, au final, par différentes manières d'habiter un quartier ségrégué ? -selon la manière dont ils habitent leur quartier, certains adolescents de ZUS subissent-ils plus que les autres les externalités négatives de la ségrégation urbaine ? Les mobilités quotidiennes jouent ainsi un rôle fondamental à l'adolescence car elles sont le support du passage progressif du monde familier au domaine public urbain. Elles mettent notamment à l'épreuve les habitudes d'action que les adolescents ont acquises dans leur quartier de résidence ou dans leur famille. Elles donnent ainsi lieu à des interactions, qui si elles sont d'une autre nature que dans ces deux sphères, n'en sont pas moins socialisantes. Les pratiques de mobilité participent de ce fait aux différentes manières d'habiter des adolescents, tout autant que les interactions quotidiennes qu'ils ont dans leur famille ou dans leur quartier. Se focaliser sur les ZUS permet alors d'enrichir les approches traditionnelles de la ségrégation, qui insistent sur une influence néfaste du cadre urbain sur les adolescents et ne prennent pas en compte les effets socialisants de leurs pratiques de mobilité. Nous montrons que ces pratiques sont cependant déterminées par trois éléments principaux : l'environnement social, économique et géographique des adolescents ; les dispositions qu'ils ont acquises dans la sphère familiale ou leur quartier de résidence ; les épreuves de co-présence avec des citadins d'un autre milieu social et résidentiel dont ils ont déjà fait l'expérience. Pour répondre à nos questions de recherche, nous nous appuyons sur des matériaux statistiques (l'enquête global transports et des indicateurs d'accès en transports en commun aux principales aménités urbaines franciliennes), une ethnographie d'un an dans une maison de quartier d'une ZUS de grande couronne ainsi que des projets de recherche-action dans sept établissements scolaires. Ces projets articulent quatre-vingt douze entretiens semi-directifs d'une heure et des ateliers thématiques sur la mobilité (photographies et écriture de textes). Ces matériaux nous ont permis de mettre en évidence les contraintes spécifiques qui pèsent sur la mobilité des adolescents de ZUS, mais également d'élaborer sept manières typiques d'habiter un quartier ségrégué ou à proximité. L'objectif de la construction de cette typologie n'est alors pas de classer stricto sensu les adolescents, mais de comprendre et d'expliquer pourquoi, dans un contexte donné, ils habitent de telle ou telle manière leur quartier / This PHD aims at documenting the spatial mobility practices of the teenagers who live in segregated neighbourhoods, so as to promote an understanding of life in such places and to explore potential desegregation effects of increased mobility. This issue is addressed here through the case of the "Zones urbaines sensibles" (ZUS) in the Parisian region, mainly the “cités” as coined by the French. So as to understand what distinguishes the teenagers who live in ZUS from the others, so as to understand also what divides them, we have chosen to apprehend them under the double angle of their district and social background. That double angle allows to take into account the social socio-spatial distinctions within the ZUS but also to question the theory of a gradual replacement of the social issue by “a new urban issue” : social problems would no longer be apprehended as class conflicts centred on work but as segregation. The fact of taking into account the mobility capacities of the teenagers living in ZUS without disregarding the influence of their residential and social environment on these practices leads us then to wonder whether the working and lower middle-class teenagers of ZUS have a specific and homogeneous use of space inside and outside their district?In order to answer this question, we mainly focused on three materials : the Parisian metropolitan mobility survey, an ethnographic survey of about one year with young boys frequenting the local community centres of a municipality in the outer suburbs, seven in-school research projects consisting in about ninety-two one-hour interviews as well as thematic work on mobility in class (photos and writing mainly). These materials reveal seven predominant ways of using the space inside and outside the neighbourhood including public transportation. These seven predominant ways, influenced by social and territorial variables, depict the heterogeneity of the inhabitants of the ZUS
188

KOORDINAČNÍ SCHOPNOSTI V DLOUHODOBÉ KONCEPCI SPORTOVNÍ PŘÍPRAVY / Coordination abilities in long-term concept sports training of children

Oburková, Renata January 2011 (has links)
Title Coordination abilities in long-term concept sports training of children Objective The point of the thesis is handle the issue of coordination ability. In the first part of the thesis I will talk about general issues of children's sports training, developmental patterns and the characteristic of sensitive periods. The fundamental basis of my research part is find out how the coordination skills involved in long-term sports training, what is their role in motor development of children and what their biological basis. Methods The thesis has a theoretical character and it uses qualitative methods: compares, analyses and interprets texts and data acquired through background research. Results Coordination skills have proven essential element of successful mastery of motor skills in the concept of long-term sports training more or less dependent on coordination. If there are individual skills developed in the sensitive periods is very difficult to catch up with missed this and achieve the same level of skills acquired. Important role in the development of coordination skills and heredity plays a connection with the state and function of the central nervous system. Key words sports training of children, coordination, development, sensitive periods
189

Ethanol from photoperiod-sensitive sorghum: a study on biomass structure and process optimization

Xu, Feng January 1900 (has links)
Doctor of Philosophy / Department of Biological and Agricultural Engineering / Yong Cheng Shi / Donghai Wang / Cellulosic ethanol made from low cost lignocellulosic biomass has been considered as new generation transportation fuel with economic and environmental advantages. Photoperiod-sensitive (PS) sorghum, because of its high biomass yield (2.6 kg dry mass/m2), about 18% of soluble sugar in dry mass, and drought tolerance, is a promising biomass for ethanol production. The overall goals of this study are to develop an efficient approach to convert PS sorghum to ethanol and to understand the structural characteristics of biomass. For increasing the efficiency of biomass conversion, an integrated method, using diluted sulfuric acid pretreatment, has been developed to utilize both the structural polysaccharide (cellulose) and the soluble sugar (sucrose, glucose, and fructose) for fermentation. Response surface methodology was employed to optimize the pretreatment condition for maximizing the cellulose-glucose conversion. Simultaneous enzymatic hydrolysis and yeast fermentation was used for ethanol production. The effects of the buffer concentration, the inoculation dosage and time, and the fermentation temperature were investigated for maximizing ethanol yield. A total conversion efficiency of 77.2% and an ethanol concentration of 2.3% (v/v) were obtained after 72 h fermentation. About 210 kg (~266 Liters) ethanol could be produced from one ton dry mass of PS sorghum under the optimized condition. The structural features of the PS sorghum were studied using techniques including scanning electron microscopy and X-ray diffraction/scattering. Biomass at different botanic locations was investigated. Wide-angle X-ray diffraction (WAXD) study showed that the PS sorghum rind had oriented crystal peaks and the highest degree of crystallinity, whereas the crystalline structures of the inner pith and leaf were less ordered. The results from WAXD suggested that crystalline cellulose was melted at 120 °C before its significant degradation. Both the cellulose crystallinity and the crystal size at the dimension lateral to fiber direction increased as the temperature increased from 120 to 160 °C. The efficiency of enzymatic hydrolysis increased because the protective structure was damaged and most hemicellulose was removed, resulting in the increase in accessible area as suggested by small-angle X-ray scattering result of the increased length of microvoids. The results from WAXD also suggested a simultaneous hydrolysis and crystallization of cellulose by acid.
190

Frequent Itemset Hiding Algorithm Using Frequent Pattern Tree Approach

Alnatsheh, Rami H. 01 January 2012 (has links)
A problem that has been the focus of much recent research in privacy preserving data-mining is the frequent itemset hiding (FIH) problem. Identifying itemsets that appear together frequently in customer transactions is a common task in association rule mining. Organizations that share data with business partners may consider some of the frequent itemsets sensitive and aim to hide such sensitive itemsets by removing items from certain transactions. Since such modifications adversely affect the utility of the database for data mining applications, the goal is to remove as few items as possible. Since the frequent itemset hiding problem is NP-hard and practical instances of this problem are too large to be solved optimally, there is a need for heuristic methods that provide good solutions. This dissertation developed a new method called Min_Items_Removed, using the Frequent Pattern Tree (FP-Tree) that outperforms extant methods for the FIH problem. The FP-Tree enables the compression of large databases into significantly smaller data structures. As a result of this compression, a search may be performed with increased speed and efficiency. To evaluate the effectiveness and performance of the Min_Items_Removed algorithm, eight experiments were conducted. The results showed that the Min_Items_Removed algorithm yields better quality solutions than extant methods in terms of minimizing the number of removed items. In addition, the results showed that the newly introduced metric (normalized number of leaves) is a very good indicator of the problem size or difficulty of the problem instance that is independent of the number of sensitive itemsets.

Page generated in 0.1245 seconds