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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.
281

Ultrasonic propagation in liquids : I. Application of pulse technique to velocity and absorption measurements at 15 megacycles

January 1946 (has links)
by J.R. Pellam and John Galt. / "June 10, 1946." "OEMsr-262." / Includes bibliographical references.
282

Factors contributing to the retention of volunteer 4-H club leaders in Ohio /

Bigler, Nancy M. January 1900 (has links)
Thesis (M.S.)--Ohio State University, 1982. / Includes bibliographical references (leaves 95-97). Available online via OhioLINK's ETD Center.
283

CARBON-PHOSPHORUS BOND FORMATION: NEW METHODOLOGIES FOR THE PREPARATION OF ORGANOPHOSPHORUS COMPOUNDS OF BIOLOGICAL INTEREST

Belabassi, Yamina 21 April 2009 (has links)
The work presented in this dissertation deals with the development of new methodologies for P-C bond formation as well as synthesizing biologically relevant organophosphorus compounds. A distinct emphasis is given to the important synthetic targets, the H-phosphinates. A review of relevant literature is provided in Chapter 1. Chapter 2 describes the synthesis and structural analyses, of triphenylmethyl-containing phosphorus compounds. For the first time, both phosphonothioic and boranophosphonic acids have been characterized by single X-ray diffractometry. The third chapter details the preparation and the reactivity of phosphine-borane complexes. Novel dialkoxyphosphine-borane complexes were introduced, both as general synthetic intermediates for the preparation of H-phosphinates or disubstituted phosphinic acids, and as boranophosphonate precursors. Related to this chemistry, silylation of an H-phosphinate intermediate can also be conducted and the resulting phosphonite protected with borane. This allows the temporary protection of the sensitive P-H group, so that manipulations of the alkyl chain might be conducted. In chapter 4, the palladium-catalyzed cross-coupling reaction of dialkylphosphites with aryl and heteroaryl halides is presented. An efficient, versatile and economically attractive alternative to the original Hirao cross-coupling by using only 1 mol% (or less) Pd(OAc)2/dppf is described. Moreover, first example of palladium-catalyzed P-C bond formation between activated aryl chlorides and a phosphite are herein reported. Chapter 5 focuses on the free-radical hydrophosphinylation of alkynes. The triethylborane-initiated radical addition of sodium hypophosphite to terminal alkyne affords the previously unknown 1,1-bis-H-phosphinates, precursors of the biologically relevant 1,1-bisphosphonates (e.g., treatment of bone diseases). Thus, the oxidative conversion of 1,1-bis-H-phosphinates to the corresponding bisphosphonates, as well as the synthesis of a series of bio-conjugates (steroids, carbohydrates, fluoroquinolones) was investigated. In the last chapter, the palladium-catalyzed hydrophosphinylation of hypophosphorous acid derivatives to terminal alkynes is reported. In an effort to improve the regioselectivity of the reaction, various terminal alkynes were tested, as well as the solvent and catalyst system.
284

Revisorns yrkesroll och oberoende : En utredning om hur revisorer förebygger risken för beroende gentemot klient

Haile, Simon, O'Regan, Sean January 2013 (has links)
I denna utredning har vi undersökt hur beroendeproblematiken påverkat regler och professionalism inom revisorsyrket på de större revisionsbyråerna. Vi har genom teori och intervjuer sökt klargöra yrkesattribut, samband, risker och förebyggande åtgärder mot den enskilde revisorn, samt dennes revisionsbyrås beroende gentemot klient. Vi har från respondenterna stött på överensstämmande uppgifter gällande hot såsom ekonomiskt beroende, alltför informella kundrelationer, tilltagande konkurrens och tung arbetsbörda, vilken riskerar att gå ut över revisionsarbetets oberoende. De förebyggande åtgärderna som revisionsbyråerna använder sig av för att stävja beroendehot är lagarbete, utbildning, avgränsade arbetsuppgifter, kontrollfunktioner. Vi har kommit fram till att den analytiska förmågan hos revisorn är viktig i sammanhanget och kan komma att få utökad betydelse i förlängningen. Vi har sedan ställt frågan hur de stora revisionsbyråernas utökade konsultverksamhet har påverkat branschens fokus på lönsamhet. Vi ser en fortsatt expansion av konsulttjänsternas lönsamhet som en andel av branschens aggregerade intäkter. Teoretiker, yrkesmän och lagstiftare arbetar konsekvent med att utforma ett praktiskt regelverk, vilket bland annat omfattar den oberoendeproblematik som vi har behandlat. Ett stort problem är att behålla jämvikt mellan lönsamhet och oberoende i en bransch som är så pass föränderlig.
285

The Effects of Polo-like Kinase 4 on Chromosomal Stability, Cell Migration and Tumourigenesis

Rosario, Carla 31 August 2011 (has links)
Plk4 is the most divergent member of the family of polo like kinases (Plks). Plk4-/- embryos arrest at approximately day 7.5 p.c. but Plk4+/- mice are viable and fertile. However, 50% of Plk4+/- mice develop spontaneous tumours of the liver, lung and soft tissues by 2 years of age. Here I investigate the mechanisms that underlie Plk4-related tumourigenesis. Plk4+/- murine embryonic fibroblasts (MEFs) spontaneously become immortal in vitro with increasing passage number and are tumourigenic in vivo when injected into NOD SCID mice. Cytogenetic analysis showed that Plk4 deficient cells are chromosomally unstable with a large number of chromosomal aberrations and increased ploidy. These results demonstrate that early loss of a single Plk4 allele is sufficient to drive cell immortalization, chromosomal instability and tumourigenicity in vivo. In two independent expression array analyses, gene expression patterns that would decrease cell migration were overrepresented in Plk4+/- MEFs. A series of spreading and migration assays functionally validated these results, supporting the hypothesis that Plk4 regulates cell motility. Endogenous Plk4 localized to filopodia and lamellipodia in motile cells and to protrusions of spreading cells; the latter localization was transient and it disappeared by 4h after cell seeding, at which point Plk4 was located in the centrosomes, as typically observed in interphase cells. Transient transfection with Flag-Plk4 enhanced spreading and migration, as well as actin remodeling. Taken together, these data demonstrate temporal regulation of Plk4 in relation to the process of membrane remodeling, and a functional role for Plk4 in cell motility. Plk4 is haploinsufficient for tumour suppression in mice. Plk4 is located at human chromosome 4q28, a region often deleted in primary liver cancer specimens. Here I show that loss-of-heterozygosity (LOH) occurs at the Plk4 locus in ≈50% of human hepatocellular carcinomas (HCC) as well as in preneoplastic cirrhotic liver nodules. LOH at Plk4 is associated with reduced Plk4 expression in HCC tumours, but not with mutations in the remaining allele. These results implicate Plk4 as a potential haploinsufficient tumour suppressor in the genesis of human HCC. With continuing high rates of the predisposing conditions Hepatitis B and non-alcoholic steatohepatitis, and delayed diagnosis, HCC is a global health issue and carries a grave prognosis. A better understanding of genetic predisposition will help guide future screening programs.
286

The Effects of Polo-like Kinase 4 on Chromosomal Stability, Cell Migration and Tumourigenesis

Rosario, Carla 31 August 2011 (has links)
Plk4 is the most divergent member of the family of polo like kinases (Plks). Plk4-/- embryos arrest at approximately day 7.5 p.c. but Plk4+/- mice are viable and fertile. However, 50% of Plk4+/- mice develop spontaneous tumours of the liver, lung and soft tissues by 2 years of age. Here I investigate the mechanisms that underlie Plk4-related tumourigenesis. Plk4+/- murine embryonic fibroblasts (MEFs) spontaneously become immortal in vitro with increasing passage number and are tumourigenic in vivo when injected into NOD SCID mice. Cytogenetic analysis showed that Plk4 deficient cells are chromosomally unstable with a large number of chromosomal aberrations and increased ploidy. These results demonstrate that early loss of a single Plk4 allele is sufficient to drive cell immortalization, chromosomal instability and tumourigenicity in vivo. In two independent expression array analyses, gene expression patterns that would decrease cell migration were overrepresented in Plk4+/- MEFs. A series of spreading and migration assays functionally validated these results, supporting the hypothesis that Plk4 regulates cell motility. Endogenous Plk4 localized to filopodia and lamellipodia in motile cells and to protrusions of spreading cells; the latter localization was transient and it disappeared by 4h after cell seeding, at which point Plk4 was located in the centrosomes, as typically observed in interphase cells. Transient transfection with Flag-Plk4 enhanced spreading and migration, as well as actin remodeling. Taken together, these data demonstrate temporal regulation of Plk4 in relation to the process of membrane remodeling, and a functional role for Plk4 in cell motility. Plk4 is haploinsufficient for tumour suppression in mice. Plk4 is located at human chromosome 4q28, a region often deleted in primary liver cancer specimens. Here I show that loss-of-heterozygosity (LOH) occurs at the Plk4 locus in ≈50% of human hepatocellular carcinomas (HCC) as well as in preneoplastic cirrhotic liver nodules. LOH at Plk4 is associated with reduced Plk4 expression in HCC tumours, but not with mutations in the remaining allele. These results implicate Plk4 as a potential haploinsufficient tumour suppressor in the genesis of human HCC. With continuing high rates of the predisposing conditions Hepatitis B and non-alcoholic steatohepatitis, and delayed diagnosis, HCC is a global health issue and carries a grave prognosis. A better understanding of genetic predisposition will help guide future screening programs.
287

När närmiljö blir lärmiljö : Ett projekt om utomhusmatematik i årskurs 5

Lissollas, Mona January 2012 (has links)
Syftet med detta examensarbete har varit att genom lektioner, observationer, utvärderingar samt intervjuer med elever och lärare få en uppfattning om hur närmiljön vid skolan används idag i matematikundervisningen, hur den skulle kunna användas mera samt få en uppfattning av hur eleverna upplever utomhusundervisning i matematik och hur det påverkar elevernas lärande. Efter en litteraturstudie genomfördes ett projekt utomhus med matematiklektioner som handlade om geometri. Lektionerna bestod bland annat av att öva på geometriska former, skala, mäta med olika mätredskap, beräkna omkrets och area, uppskatta längder och använda gamla mätmetoder.   Resultatet av projektet och intervjuerna visar att lärarna till viss del, mestadels sporadiskt, använder utemiljön i sin matematikundervisning speciellt tillsammans med de yngre barnen. Det finns en vilja bland lärare att använda närmiljön mer om tid kan frigöras till att få idéer, inspiration och planera övningar. En fördel som lärarna ser med matematikundervisning ute är att eleverna verkar komma ihåg och få en djupare kunskap för de moment som genomförts ute. Eleverna som deltagit i projektet med matematiklektioner i utemiljö uppfattar utomhusundervisning som något positivt och  flertalet upplever att de lär sig matematik bättre då de får vara ute och röra på sig samtidigt i friska luften. Det negativa var det kyliga vädret.
288

Ren eller oren revisionsberättelse : En undersökning om revisorns träffsäkerhet i konkursdrabbade gasellföretag 2006-2011

Antonsson, Malin, Borup, Malin January 2012 (has links)
Gasellföretag har en snabb tillväxt under en kort tidsperiod men trots en snabb tillväxt försätts en del av företagen i konkurs efter att de erhållit utmärkelsen till gasellföretag. Tidigare forskning tyder på att revisorer som arbetar på en Big 4 revisionsbyrå är mer träffsäkra vid utgivandet av revisonsberättelser än de revisorer som arbetar på andra revisionsbyråer. Tidigare forskning visar också på att auktoriserade revisorer är mer träffsäkra vid utgivandet av revisionsberättelser än godkända revisorer. Syftet med arbetet är att kartlägga och förklara revisorns träffsäkerhet av den sista revisionsberättelsen i gasellföretag som försatts i konkurs. Vidare vill vi analysera vilken typ av revisor som är mest träffsäker vid utgivandet av en oren sista revisionsberättelsen till gasellföretag som försätts i konkurs. Genom en deduktiv ansats kommer vi testa befintliga teorier för att sedan antingen förkasta eller acceptera hypoteser och genom en kvantitativ metod kommer vi samla in sekundärdata till undersökningen. Vårt resultat visar att revisorns träffsäkerhet vid utgivandet av revisionsberättelser inte beror på vilken revisionsbyrå denne arbetar på eller vilken examensnivå revisorn uppnått. Det som istället kan ha betydelse för om ett konkursdrabbat gasellföretags sista revisionsberättelse blir ren eller oren är företagets soliditet.
289

Digitaliseringens förändring av bokbranschen

Björk, Patric, Sundman, Liv January 2012 (has links)
This is a bachelor thesis, written at the business studies institute, Uppsala Unviersity, exploring how digitalization has affected the Swedish book industry. This is done by studying how the introduction of the e-book has changed the way the publishers work and what problems and opportunities arise with the new way to publish and consume books. The technology optimists, that existed around the turn of the millennium, when the e-book came, made predictions along the lines of the physical book having ceased to exist within five to ten years. But the physical paper books do very much still exist, so haven’t the change happened as predicted? The purpose of this thesis is as follows: How has introduction of the e-book affected the relationship between the Swedish publishers and the book as a whole? This means that we consider the book as a concept, as a resource or product, and study how a change in this product affect publishers. The theoretical framework used is basically classical network theory. We study the book as a resource that exists through relationships with other resources, with the help of the 4R model. The information has been gathered through both a study of literature and interviews with subjects. The litterature study consisted of reading the newspaper Svensk Bokhandel (SvB) Years 2004-2010. It provided us with enough information to make a network map of the actors within the Swedish book industry. From this network map identified the key actors and interviews took place with a number of these. The empirical data has first been split into two scenarios; the book industry around year 2000 and 2012. The information gathered about these two points in time were then separated into the four types of resources defined by the theory. This was done to illustrate the changes that has occurred during the past decade. The interfaces between resources were then examined in the analysis and the changes in weight and variation that occurred was noted. The reasons that caused the observed transformations of the interactions has been investigated and these have been noted. The conclusion that has been reached is that the weight of the network is relatively unchanged while the overall variation has increased. This change in variation have taken the guise of new flows of information and new ways to process, distribute and consume the book. The essay ends with a discussion of the book industry's future and the parallels and differences to markets that have undergone similar changes. / Detta är en kandidatuppsats, skriven vid företagsekonomiska institutionen vid Uppsala unviersitet, som undersöker hur digitaliseringen har påverkat den svenska bokbranschen. Detta görs genom att studera hur e-boken har förändrat förlagens sätt att arbeta samt vilka problem och förutsättningar som uppkommit med de nya sättet att publicera, distribuera och konsumera böcker. Den stora teknikoptimism som fanns kring millennieskiftet då e-boken kom gav tongångar i stil med att den fysiska boken inom fem till tio år skulle ha upphört att publiceras. Pappersböcker säljs i hög grad fortfarande, och varför har förändringen inte skett snabbare? Uppsatsens syfte lyder enligt följande: Hur har e-bokens inträde på marknaden påverkat relationen mellan de svenska förlagen och boken som en enhet? Den teoretiska referensram som använts är i grund och botten klassisk nätverksteori. Vi studerar boken som en resurs som existerar i form av relationer och kopplingar till andra resurser, med hjälp av den s.k. 4R-modellen. Undersökningen är blandad litteraturstudie och intervjubaserad. Litterturstudien bestod av att läsa tidningen Svensk Bokhandel(SvB) årgångarna 2004-2010. Det medgav en klar nätverkskarta över vilka aktörer som verkade inom den svenska bokbranschen. Utifrån denna nätverkskarta identifierades de centrala aktörerna och intervjuer skedde med ett antal av dessa. Empirin har först delats upp i två scenarion; bokbranschen kring 2000 samt 2012. Den information som innehafts angående de två tidpunkterna separerades sedan i de fyra typerna av resurserna som definieras av teorin. Detta för att belysa de förändringar som skett under det senaste decenniet. Gränssnitten mellan resurserna undersöktes sedan i analysen och de förändringar i tyngd och variation som skett noterades. De anledningar som orsakat de observerade transformationerna i interaktionerna har undersökts och även dessa har noterats. Den slutsats som nåtts är att tyngden inom nätverket är relativt oförändrad medans den generella variationen har ökat. Denna variationsförändring har tagit skepnad av nya informationskanaler samt nya sätt att bearbeta, distribuera och konsumera boken. Uppsatsen avslutas med en diskussion kring bokbranschens framtid samt paralleller och skillnader mot marknader som genomgått likande förändringar.
290

Cloning and Expression of Arabidopsis endo-1,4-£]-glucanase in Pichia pastoris

Chao, Shih-hsien 05 February 2010 (has links)
In recent years. as industrialized society developed. people have made a lot of environment pollution problems owing to overusing fossil fuel, moreover. fossil fuel is going to deplete. As the result. the study of the substitute energy is promoted. Ligonocellulose (lignin, cellulose and hemicelluloses are included) are the most plentiful renewable resources in the nature, and it have high economic values which extensively use on food, paper and energy. Recent years, it is a hot issue that decomposing cellulose into the minimum unit called glucose, and further, fermenting into alcohol to generate biomass energy. This research goal is cloning Arabidopsis endo-1,4-£]-glucanase and transfer to Escherichia coli(DH5£\). Selection pPICZ£\A the success transferr DNA Fragment. Then to sequence and because of cell in pPICZ£\A have expression in Pichia. pastoris. AOX1 promoter have Mass productions Arabidopsis endo-1,4-£]-glucanase gene in Pichia pastoris. Carries on the extracellular expression by the methyl alcohol induction way. Can obtain recombinant DNA protein. However the Western blotting analysis demonstration has this enzyme active protein At4g11050 pellet Molecular weight about 89 KDa. Again by way of congo red and Dye-CMC assay activeness of the examination enzyme protein. The result discovers At4g11050 in the pellet cell activity compares with negative control has the obvious activity.

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