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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.
151

Exact Solutions in Planar Elasticity via the Cauchy-Riemann Equations

Granath, Andreas January 2022 (has links)
In many engineering applications, one is interested in structures with elastic properties which undergo deformation due to external loads. This interest has motivated a deep study of the equations underlying the deformation and how to solve them during the two last centuries. In this thesis, we propose a method that allows us to construct exact solutions to these equations. We prove that the partial differential equation governing the deformation is equivalent to the well-studied Cauchy-Riemann equation on the unit disk. Furthermore, we prove sufficient conditions for when the exact solutions to the Cauchy-Riemann equation on the unit disk can be used to construct solutions to the physical problem. We end the thesis by outlining a method for solving the elasticity equation in a general simply connected domain with a known conformal mapping to the unit disk. This method simplifies the formulas of Kolosov and Muskhelishvili, which are constructed by complex potentials in a similar, but more indirect way. It also allows us to obtain solutions in domains where standard numerical methods, such as e.g. the finite element method, proves difficult or even impossible to apply.
152

Searching for the optimal radiotherapy treatment time, dose and fractionation - the role of hypoxia and reoxygenation : A modelling study

Lindblom, Emely January 2014 (has links)
The search for the optimal choice of treatment time, dose and fractionation regimen is one of the major challenges in radiation therapy. Several aspects of the radiation response of tumours and normal tissues give different indications of how the parameters defining a fractionation schedule should be altered relative to each other which often results in contradictory conclusions. For example, the increased sensitivity to fractionation in late-reacting as opposed to early-reacting tissues indicates that a large number of fractions is beneficial, while the issue of accelerated repopulation of tumour cells starting at about three weeks into a radiotherapy treatment would suggest as short overall treatment time as possible. Another tumour-to-normal tissue differential relevant to the sensitivity as well as the fractionation and overall treatment time is the issue of tumour hypoxia and reoxygenation. The tumour oxygenation is one of the most influential factors impacting on the outcome of many types of treatment modalities. Hypoxic cells are up to three times as resistant to radiation as well oxygenated cells, presenting a significant obstacle to overcome in radiotherapy as solid tumours often contain hypoxic areas as a result of their poorly functioning vasculature. Furthermore, the oxygenation is highly dynamic, with changes being observed both from fraction to fraction and over a time period of weeks as a result of fast and slow reoxygenation of acute and chronic hypoxia. With an increasing number of patients treated with hypofractionated stereotactic body radiotherapy (SBRT), the clinical implications of a substantially reduced number of fractions and hence also treatment time thus have to be evaluated with respect to the oxygenation status of the tumour. The perhaps most promising tool available for the type of study aiming at determining the optimal SBRT approach with respect to fractionation is radiobiological modelling. With clinically-derived tissue-specific radiobiological parameters and well-established survival models, in silico modelling offers a wide range of opportunities to test various hypotheses with respect to time, dose, fractionation and details of the tumour microenvironment. Any type of radiobiological modelling study intended to provide a realistic representation of a clinical tumour should therefore take into account details of both the spatial and temporal tumour oxygenation. This thesis, consisting of papers I-III and a summary, presents the results of three-dimensional radiobiological modelling of the response of tumours with heterogeneous oxygenation to various radiation qualities, fractionation schemes, oxygenation levels and dynamics using different survival models. The results of this work indicate that hypoxia and its dynamics play a major role in the outcome of both photon and carbon ion radiotherapy, and that neglecting the oxygenation status of tumours treated with SBRT may compromise the treatment outcome substantially. Continued to include clinical studies on the impact of hypoxia on the treatment outcome in lung cancer patients treated with SBRT, this project will hopefully advance the evolution towards routinely incorporating functional imaging of hypoxia into treatment planning. This is ultimately expected to result in increased levels of local control with more patients being cured from their cancer.
153

“Varför ska vi lära oss det här?” : - En undersökning av hur väl högstadieelevers intressen stämmer överens med den svenska läroplanen.

Strömbom, Rebecka January 2020 (has links)
Forskning visar att intresset för NO som skolämne är lågt bland högstadieelever, vilket är oroande dels på grund av att intresse är ett av målen i den svenska läroplanen, dels på grund av det förutspås en brist på naturvetare i framtiden. Att kartlägga elevers intressen kan därför vara ett verktyg för att bättre förstå varför intresset för NO i skolan är lågt. Syftet med denna rapport är därför att undersöka intressen hos elever i årskurs 9 i Sverige och sedan jämföra resultatet med det som ingår i läroplanen. Detta gjordes med ROSES-studien som skickades ut till elever i årskurs 9 över hela Sverige. Enkäten omfattade ämnesområden inom NO-ämnen och svaren på frågor angående ämnesområdena med koppling till biologi ligger till grundför denna studie. De punkter som berörde specifikt biologi plockades ut och svaren analyserades utifrån hur väl representerade dessa var i det centrala innehållet  i kursplanen. Färre än hälften av de svarande eleverna ansåg NO-ämnena vara intressanta, och få punkter angavs vara särskilt intressanta men vissa av de som var mer intressanta är ändå väl representerade i det centrala innehållet. Resultatet diskuteras i relationen till intresse, lärande och motivation, ämnesdidaktiska implikationer och förslag på vidare forskning diskuteras. Slutsatsen i arbetet är att NO-ämnena är måttligt intressanta och att en del av vad som intresserar elever specifikt inom biologi är ändå representerat i det centrala innehållet.
154

Synthesis of single-layer graphene and studying oxidation behaviour of copper foil.

Rafei, Mouna January 2020 (has links)
The ultimate aim of the current study is to investigate the electron transfer from copper (Cu) to single layer graphene through a thin Cu oxide layer. Therefore the project is divided into two main parts. In the first part, single layer graphene is synthesized with chemical vapour deposition technique on a Cu foil and the grown graphene is characterized by means of Raman spectroscopy and scanning electron microscopy (SEM). We tune different experimental parameters to grow high quality graphene. We show that a pre-annealing of the Cu foil, in Varigon environment, modifies the Cu crystal grain size and that modifies the growth dynamic of the graphene. Optimum annealing time in correlation with growth time results in high Ǵ/G ratio and a narrow FWHM of Ǵ band in Raman spectrum. The second part of the project focuses on controlling the surface oxidation of Cu foil with respect to the oxide layer thickness. The surface and cross section of the oxidized Cu foil is examined by SEM and the presence of oxide layer is confirmed via energy dispersive X-ray spectroscopy (EDS) analysis. We show that the surface roughness of the oxide layer can be minimized by controlling the oxidation condition with a minimum oxide layer thickness of 18 μm. In addition the grain size of the oxide layer is getting larger with increasing the oxidation temperature. Furthermore, the oxygen concentration in the oxide layer is controlled through a controlled reduction process which is confirmed via EDS analysis. XPS spectroscopy is also used for elemental analysis as well as revealing the chemical state of the Cu oxide.
155

Characterization of the Carnitine Transporter, OCTN2: Functional Impact of Mutations and Its Role in COVID-19 Treatment Related Drug-Drug Interactions

Rödin, Mattias January 2020 (has links)
<p>P.g.a COVID-19 gjordes presentationen på distans över zoom.</p>
156

Teaching sensitive topics within an Islamic context : a female beginner teacher's autoethnographic account

Aboo Gani, Sadiya January 2020 (has links)
The focus of this study was to understand my experiences of teaching sensitive topics in my professional capacity, as a female beginner teacher who has an Islamic upbringing and strong religious views according to which I live. The purpose of this study was to make sense of these personal and professional experiences when teaching sensitive topics as an Islamic beginner female teacher. In so doing this study sought to contribute to body of knowledge about key concepts namely sensitive topics, an Islamic context, female beginner teacher identity and autoethnography as research design. The literature reviewed for this research study was centred around the said key concepts and included scholarly work by Collins (2017), Lowe and Jones (2015), Du Bois (2014), and Anacona (2014). Theoretically, this study was underpinned by an interpretivist epistemological paradigm informed by Berg (2007) and from a conceptual point of view I drew on tenets of both the religion and feminist theory guided by the work of Rambo (1999). Data was generated in the form of short anecdotal self-reflective narratives spanning over 25 years and encapsulated the gist of my upbringing and later experiences which all influenced the ways in which I have experienced the teaching of sensitive topics as a female beginner teacher female within an Islamic context. Findings were divided into three main themes, namely the Islamic religion, Islam and gender and teaching sensitive topic as a Muslim, female beginner teacher. Findings were refined into relevant subthemes. The gist of the findings revealed that a strict Islamic upbringing contributed largely to the discomfort experienced by a female teacher when teaching topics of a sensitive nature, such as sexual education which is compulsory in the current Life Orientation curriculum. Findings further pointed to the fact that this discomfort can be alleviated through self-talk, engagement with scholarly work and deep thought incited by engagement with sensitive topics. Recommendations were suggested for classroom practice. / Dissertation (MEd)--University of Pretoria, 2020. / Humanities Education / MEd / Unrestricted
157

Gymnasieelevers uppfattning avkursplanen och deras slutbetyg i Biologi 1 : En kvantitativ undersökning av elevers uppfattning av syfte ochcentralt innehåll i relation till slutbetyg.

Undseth, Michelle January 2021 (has links)
Tidigare forskning har visat att elevers förväntningar på hur de ska prestera i studier till stor del leder till att de presterar på den ungefärliga nivån som de förutspått sig att prestera. Det saknas dock studier kring hur elevers uppfattning kring syftet i ämnesplanen och det centrala innehållet i kursplanen påverkar elevernas betyg. Det är dessa faktorer (det centrala innehållet och syftet) som kunskapskraven baseras på och elevernas förmåga att arbeta efter dessa är därför av stor vikt. I denna studie har det via en enkät undersökts hur lätt/svårt gymnasieelever i Stockholmsområdet uppfattar syftet i ämnesplanen för Biologi på gymnasienivå. Det undersöks även hur intressant de tycker att de olika ämnesområdena i det centrala innehållet för kursen Biologi 1 är. Utifrån dessa data har det analyserats ifall att det finns några signifikanta samband mellan dessa variabler samt elevernas förväntade betyg och elevernas slutbetyg i kursen Biologi 1. Studien visar att elever som har lätt att uppfatta syfte nr 1: Kunskaper om biologinsbegrepp, modeller, teorier och arbetsmetoder samt förståelse av hur dessa utvecklas och syfte nr3: Förmåga att planera, genomföra, tolka och redovisa fältstudier, experiment och observationer samt förmåga att hantera material och utrustning i kursplanen har ett signifikant högre slutbetyg. Det centrala innehåll som hade ett signifikant samband med slutbetyget var ”Evolution”. Elever som visade högre intresse för ”Evolution” hade också ett högreslutbetyg. För de elever som deltog i denna studie var medelvärdet för elevernas slutbetyg högre än medelvärdet för slutbetyg i hela Sverige. Resultaten i denna studie bör därför endast ses som en indikator på vilka delar i syftet och det centrala innehållet som elevernas förväntningar på kan ha betydelse för högpresterande elevers slutbetyg.
158

Elevers kunskaper inom ekologi samt kopplingar till deras attityder om att bevara natur och miljö – en fallstudie i årskurs 9

Fitwi, Fitsumberhan January 2021 (has links)
Att börja arbeta för ekologisk hållbarhet är något som är brådskande. Frågan om biologisk mångfald har blivit en av de vanligaste globala miljöfrågorna. Miljömedvetna ungdomar är potentiellt de största förändringsagenterna för långsiktigt skydd och hantering av miljön. Således är det intressant att undersöka vilka kunskaper och attityder eleverna har i högstadiet. Därför genomfördes denna studie för att bedöma eleverna kunskapsnivå och attityd till miljön samt för att se om det finns samband mellan elevens kunskaper om ekologi och attityder till miljö. Undersökningen genomfördes på ett högstadium i en mindre kommun i norra Sverige. Studien har en metodologi av kvantitativ karaktär. Studien har utförts med hjälp av enenkätundersökning. Enkäten skickades ut digitalt via e-post till elever, där respondenterna själva besvarade en uppsättning frågor. Enkäten besvarades av 80 respondenter i årskurs 9. Resultaten avslöjade att en majoritet av eleverna besvarar de grundläggande ekologi kunskaps frågor på ett tillfredställande sätt samt att eleverna har en positiv attityd och stark miljöhänsyn. Det finns ett samband mellan kunskap och elevernas attityd till miljön, detta innebär kunskap som eleverna besitter om ekologi även påverkar deras attityd till miljön i den här studien. Sambandet mellan kunskap och attityd till miljön är starkt positiv. Eleverna har positiv attityd till miljöfrågor och uppvisar tillräckligt ekologikunskap nivå.
159

Chopin’s Introvert Paradox: Ambiguous Topics, Liminal Liveliness, and Contested Subjectivity

Gower, Sean 19 November 2019 (has links)
No description available.
160

Development of specific host cell protein assays

Ivert Nordén, Anna January 2023 (has links)
The manufacturing and the development of biotherapeutic drugs involves the expression of biotherapeutic proteins in a host cell expression system followed by a purification process. Bioanalytical methods to measure impurities such as host cell proteins (HCPs) are needed to obtain a robust process and a safe drug according to regulatory requirements. The aim of this project was to develop three specific HCP assays for detection and quantification of specific HCPsusing the Gyrolab® platform. The HCPs (Annexin A5, Clusterin and Nidogen-1) chosen for this project are generated from Chinese hamster ovary (CHO) cells. Each assay was evaluated on four different Gyrolab® BioaffyTM CDs with a comparison of column profiles, accuracy, precision and sensitivity. For each assay the best suited CD type was suggested together with possible upper limit of quantification (ULOQ) and lower limit of quantification (LLOQ) within the estimated detection range. The results indicate that the CHO Annexin A5 assay has a detection range extending from 1500 ng/ml to 2.1 ng/ml, with possible ULOQ at 1000 ng/ml and LLOQ at 3.2ng/ml using the BioaffyTM 4000 HC CD. The CHO Clusterin assay has a detection range extending from 1500 ng/ml to 0.4 ng/ml, with possible ULOQ at 1000 ng/ml and LLOQ at 0.7 ng/ml using the BioaffyTM 4000 HC CD. The CHO Nidogen-1 assay has a detection range extending from 1500 ng/ml to 0.1 ng/ml, with ULOQ at 1000 ng/ml and LLOQ at 0.2 ng/ml using the BioaffyTM1000 CD.

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