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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.
11

Optical and Material Properties of Colloidal Semiconductor Nanocrystals

Huxter, Vanessa 01 March 2010 (has links)
This thesis presents an exploration of the photophysics of colloidal semiconductor nanocrystals using both linear and non-linear optical measurement techniques. These optical methodologies are used to follow population dynamics in both singly and multiply excited nanocrystal systems as well as determine material properties of the ensemble. Topics covered in the thesis include, the identification and characterization of bulk-like nanocrystals, study of the fine structure states of the lowest energy exciton, single and multiexciton population dynamics, acoustic phonon modes, elasticity and surface stress properties of a colloidal ensemble in solution.Through linear spectroscopy, the properties of both quantum confined and bulk-like colloidal semiconductor nanocrystals are compared. The identification of a model system of bulk-like nanocrystals with a non-standard absorption profile serves to resolve an ambiguity in literature concerning their characterization. The remainder of the thesis is focused on the size-dependent properties of quantum confined CdSe colloidal nanocrystals. The population dynamics and material properties of these systems are studied using a nonlinear optical technique called transient grating. A third order transient grating measurement with a cross-polarized configuration, which follows the relaxation within the fine structure levels of the lowest energy exciton state, is demonstrated and used to compare systems with different crystal field splittings. Transient grating experiments performed with specific polarization sequences allow for selective observation of the dynamics amongst nearly degenerate levels at room temperature. Cross-polarized transient grating is also used to observe a quantized acoustic phonon mode in a series of nanocrystal samples. The observation of this mode allows experimental determination of the elasticity and surface stress of the nanocrystal ensemble in solution. The anisotropic origin of the acoustic phonon is discussed using a combination of theoretical analysis, modelling and experimental data. In addition, third- and fifth-order transient grating experiments are used to study exciton and multiexciton population relaxation dynamics. The work presented here spans the optical and material properties of quantum confined and `bulk' nanocrystals. This thesis attempts to illustrate the broad scope of the observed behaviour of colloidal nanocrystal systems and to contribute to a greater understanding of their physical properties.
12

Det nya gränsvärdet : konsekvenser för K-2 bolagen

Klintelius, Lena, Furland, Jakob January 2006 (has links)
<p>Ett av EU:s främsta syfte är att skapa fri rörelse av kapital. Genom att kontinuerligt reducera handelshinder strävar de efter att skapa lika förutsättningar mellan medlemsstaterna. I och med den globalisering som skett och fortfarande sker blir det allt mer vanligt förekommande att svenska bolag konkurrerar och samverkar med andra europeiska bolag.</p><p>Mycket har hänt på redovisnings- och revisionsområdet det senaste decenniet vilket har gjort att den svenska lagstiftningen delvis har skrivits om och anpassats efter EG:s direktiv. Internationella redovisningsstandarder har fått stort inflytande på framförallt de stora svenska bolagen. Dessa standarder var ursprungligen anpassade för börsnoterade bolag vilket har medfört att mindre svenska bolag under de senaste åren ålagts orimligt omfattande redovisningsskyldigheter. I november 2004 presenterade Justitiedepartementet en promemoria vilken bland annat avsåg förenklade redovisningsregler. Deras bedömning var att de två gränsvärdena som i dag benämns i ÅRL och BFN bör samordnas till ett gemensamt. Motiveringen till detta var att små och medelstora bolag i större utsträckning bör undantas från betungade regler gällande bokföring och bokslut. Under vintern 2005/2006 har en lag-rådsremiss och en proposition offentliggjorts där remissinstanserna BFN, FAR, SRS m.fl. givit uttryck för sina åsikter. Detta resulterade i att delvärdena i den samordnade gränsvärdet fastställdes till 50 anställda, 25 miljoner kronor i balansomslutning samt 50 miljoner kronor i totala intäkter.</p><p>Syftet med denna uppsats är att utreda vilka konsekvenser detta får för de små och medelstora bolagen i Sverige. Undersökningen har genomförts ur två perspektiv, dels för att återspegla de generella konsekvenserna med harmoniseringen och dels vilka konsekvenser det samordnade gränsvärdet blir redovisningsmässigt. För att uppnå syftet genomfördes fyra expertintervjuer. Resultatet av dessa var att redovisningsprinciperna blir något förenklade men eftersom förslaget ej trätt i laga kraft ännu är det svårt att peka på konkreta konsekvenser. Dock kan man förutse vissa skillnader avseende bland annat delårsrapportering, balansering av egenupparbetade immateriella anläggningstillgångar och restvärdesavskrivningar.</p><p>Efter att ha tagit del av respondenternas svar samt vad som sägs i lagrådsremissen kan vi konstatera att förändringarna på flera plan går mot att uppgifter ej är lagstadgade utan snarare styrs av intressenterna. Delårsrapporter är en sådan uppgift, då det ej åligger revisionsplikt på dem ser vi det som en naturlig utveckling att ta bort den lagstadgade uppgiftsskyldigheten för K3 – bolagen.</p><p>Vidare diskuteras huruvida K2 – blocket kommer innefatta bolag med allt för stora skillna-der i omfattning av verksamhet och hur detta skulle kunna undvikas. Vi föreslår en höjning av K1-blocket från tre till fem miljoner kronor i nettoomsättning där aktiebolag ej ska in-kluderas. Anledningen till detta är att få bort de minsta bolagen ur K2 – blocket genom att fler bolag bör överväga alternativa bolagsformer för att undvika allt för omfattande redovisningsmässiga skyldigheter.</p><p>Från och med den första januari 2007 träder ett nytt regelverk beträffande redovisningsprinciper i kraft i Sverige. Regelverket är delvis utformat efter EU:s redovisningsdirektiv och är ett steg i harmoniseringen. De bolag som vid årsskiftet skall till-lämpa det nya regelverket är de som ej överskrider det nya 50/25/50 - värdet, dvs. K1 och K2 - bolagen. För större bolag, K3 samt K4, kommer reglerna träda i kraft med det räkenskapsår som påbörjas första januari 2010.</p> / <p>One of EU:s primary purposes is to create freedom of movement for capital. Through continuous reducing of trade obstacles they strive to create equal conditions between the member nations. Through the globalization that has taken place and still is taking place it is increasingly common for Swedish companies to compete and cooperate with European companies.</p><p>A lot has happened in the accounting and auditor area during the last decade which has forced the Swedish legislation partly to be rewritten and adjusted to EG directives. International accounting standards has had a great deal of influence on the major Swedish companies. These standards are originally adapted for stock exchange introduced companies which in the last couple of years have resulted in unreasonable extensive accounting obligations for smaller Swedish companies. In November 2004 the ministry of Justice presented a memorandum which among other things intended to simplify accounting obligations. Their assessment was that the two threshold values that today are termed in ÅRL and BFN should be coordinated into one common threshold. The motivation for this was that small and medium companies in a greater extent should be able to make exceptions from onerous rules concerning bookkeeping and closure. During the winter 2005/2006 a referral and a government bill was made public where BFN, FAR and SRS gave expression of their opinions. This resulted in that the partial value in the coordinated threshold was established to 50 employees, 25 million in balanced turnover and 50 million in total reve-nue.</p><p>The purpose of this paper is to investigate which consequences this will have to the small and medium companies in Sweden. The investigation has been carried out through two perspectives, one to reflect the general consequences with the harmonious and also which consequences the coordinated threshold value will bring to the accounts. To reach the pur-pose four expert interviews were carried out. The conclusion of these interviews was that the accounting standards will be a bit more simplified but since the proposal has not yet become legally binding it is hard to point to concrete consequences. We can still predict to a certain extend with respect to among other things; quarterly reports, balancing of non-material internally acquired inventory and depreciation of residual values.</p><p>After studying the respondents’ answers and the referral we can establish that the changes on several levels will progress to the point of information not being statutory but rather controlled by interest organisations. Quarterly reports are that sort of task, when it is not mandatory audit on this sort of report we can not see any reason not to remove the statu-tory information obligation for the K – 3 companies.</p><p>The thesis further discusses whether the K2 – block will include companies with much too large differences in the extent of activity and how this should be avoided. We suggest a raise of the K-1 block from three too five million in net turnover, where joint-stock companies not will be included. The reason for this is to get rid of the smallest companies in the K-2 block; more companies should consider alternative company forms to avoid all too extensive accounting obligations.</p><p>Starting on the first of January 2007, the new regulation concerning accounting principles will take effect in Sweden. The regulations are partly designed according to the EU:s ac-counting directives and are a step in the harmonious direction. Those companies who will apply the new regulation at the turn of the year are those which do not exceed the new 50/25/50 value i.e. K-1 and K-2 companies. For the bigger companies, K-3 and K-4, the new regulation takes effect with the accounting year that starts on the first of January 2010.</p>
13

Optimalizace postupů pro kvantifikaci miRNA z tenkojehlových bioptických vzorků karcinomu pankreatu. / Optimization of miRNA analysis in fine-needle biopsy samples of pancreatic cancer tissue.

Čuperková, Romana January 2014 (has links)
Pancreatic cancer (PC) is extremely severe malignant disease with a five-year survival of less than 5%. Currently there is no reliable tool for the diagnosis of PC in its early stages. At the time of clinical symptoms most patients are in an advanced stage of the disease and the treatment does not usually have a significant effect. For these reasons emphasis is gradually shifting to the search for the suitable molecular markers for improvement of the diagnosis and assessment of the survival prognosis with respect to a possibility of surgical treatment. MiRNA represent one of the most promising markers, although, their examination in pancreatic tissue is a complicated process. One of the reasons is the very small amount of the source material coming from a fine needle biopsy. A second cause of problems is the subtle character of the pancreatic tissue resulting in significantly lower yields of molecular genetic analysis when compared to other epithelial tissues. An additional negative factor is heterogeneity of the tissue resulting in disproportionate representation of tumor cells within the sample. A suitable choice of procedures for isolation of nucleic acids (NA) and subsequent analysis including quantification of tumor cells is critical for accurate evaluation of the miRNA levels. This work is...
14

Climate change adaptation in agriculture - securing food, livelihoods and the environment : From a farm-perspective

Friberg, Josefine, Haugland, Tove January 2021 (has links)
Conventional agriculture has impacts on the environment such as soil degradation, biodiversity loss and pollution of ecosystems, which could be enhanced further by climate change. The effects can be more or less extensive depending on whether adaptation is carried out. Agriculture in Sweden is controlled by EU- and national regulations that set the rules and possibilities for adaptation through financial and advisory support. This study aimed to examine what impacts climate change will impose on the agriculture in Sweden, as well as how the theoretical and practical side of the adaptation measures available through policy regulations, is perceived on farm level. The question of research was: ‘How sufficient are the agricultural policy regulations in enabling Swedish farmers to adapt to climate change?’, which was investigated by interviewing Swedish farmers. The results were analyzed through the theoretical framework adaptive capacity, as a criterion for successfully enabling climate change adaptation. The results showed that several barriers exist within the regulations which can obstruct adaptation due to bureaucratic complexity and a gap between theory and practice in regard to the effectiveness of measures. The results also showed that economic, human and social capital included in the adaptation capacity concept can be strengthened for better adaptation. The discussion presented several points of improvement for regulations to adopt a practical farm-perspective in order to enable farmers to adapt to climate change. / Konventionellt jordbruk har negativa effekter på miljön, såsom markförstöring, förlust av biologisk mångfald och förorening av omgivande ekosystem, vilket kan förvärras av klimatförändringar. Effekterna kan bli mer eller mindre omfattande beroende på om anpassning genomförs. Jordbruket i Sverige styrs av Europeiska- och nationella lagar som anger regler och möjligheter för anpassning genom ekonomiska och rådgivande stöd. Studien syftade till att undersöka vilka konsekvenser klimatförändringarna kan innebära för jordbruket i Sverige, samt hur den teoretiska och praktiska sidan av anpassningsåtgärder tillgängliga genom regelverket, uppfattas på gårdsnivå. Frågeställningen för undersökningen var således: ‘Hur tillräckliga är existerande regelverk i att möjliggöra svenska jordbrukares anpassning till klimatförändringar?’. Forskningsfrågan undersöktes genom en intervjustudie med svenska lantbrukare. Resultatet analyserades genom det teoretiska ramverket Anpassnings-kapacitet som är ett kriterium för att möjliggöra klimatanpassning. Resultatet visade att det existerar hinder inom regelverket som begränsar anpassning på grund av byråkratisk komplexitet samt en klyfta mellan teori och praktik gällande utvecklingen och effekten av åtgärder, vilket gav slutsatsen att regelverkets ansträngningar i att möjliggöra anpassning är överlag otillräckliga. Resultatet visade att ekonomiskt, human- och socialt kapital som ingår i konceptet Anpassnings-kapacitet kan stärkas för att bättre anpassning ska ske. Diskussionen presenterar flera förbättringar för att regelverket ska kunna anta ett gårds-perspektiv för att göra det möjligt för lantbrukare att anpassa sig till klimatförändringarna.

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