In 1920, Leon Brillouin discovered a new kind of light scattering – Brillouin scattering – which occurs as a result of the interaction of light with a transparent material’s temporal periodic variations in density and refractive index. Many advances have since been made in the study of Brillouin scattering, in particular in the field of fiber optics. An in-depth investigation of Brillouin scattering in optical fibers has been carried out in this thesis, and the theory of stimulated Brillouin scattering (SBS) and combined Brillouin gain and loss has been extended. Additionally, several important applications of SBS have been found and applied to current technologies. Several mathematical models of the pump-probe interaction undergoing SBS in the steady-state regime have emerged in recent years. Attempts have been made to find analytical solutions of this system of equations, however, previously obtained solutions are numerical with analytical portions and, therefore, qualify as hybrid solutions. Though the analytical portions provide useful information about intensity distributions along the fiber, they fall short of describing the spectral characteristics of the Brillouin amplification and the lack of analytical expressions for Brillouin spectra substantially limits the utility of the hybrid solutions for applications in spectral measurement techniques. In this thesis, a highly accurate, fully analytic solution for the pump wave and the Stokes wave in Brillouin amplification in optical fibers is given. It is experimentally confirmed that the reported analytic solution can account for spectral distortion and pump depletion in the parameter space that is relevant to Brillouin fiber sensor applications. The analytic solution provides a valid characterization of Brillouin amplification in both the low and high nonlinearity regime, for short fiber lengths. Additionally, a 3D parametric model of Brillouin amplification is proposed, which reflects the effects of input pump and Stokes powers on the level of pump wave depletion in the fiber, and acts as a classification tool to describe the level of similarity between various Brillouin amplification processes in optical fibers. At present, there exists a multitude of electro-optic modulators (EOM), which are used to modulate the amplitude, frequency, phase and polarization of a beam of light. Among these modulators, phase modulation provides the highest quality of transmitted signal. As such, an improved method of phase-modulation, based on the principles of stimulated Brillouin scattering, as well as an optical phase-modulator and optical phase network employing the same, has been developed. Due to its robustness, low threshold power, narrow spectrum and simplicity of operation, stimulated Brillouin scattering (SBS) has become a favourable underlying mechanism in fiber-based devices used for both sensing and telecommunication applications. Since birefringence is a detrimental effect for both, it is important to devise a comprehensive characterization of the SBS process in the presence of birefringence in an optical fiber. In this thesis, the most general model of elliptical birefringence in an optical fiber has been developed for a steady-state and transient stimulated Brillouin scattering (SBS) interaction, as well as the combined Brillouin gain and loss regime. The impact of the elliptical birefringence is to induce a Brillouin frequency shift and distort the Brillouin spectrum – which varies with different light polarizations and pulse widths. The model investigates the effects of birefringence and the corresponding evolution of spectral distortion effects along the fiber, and proposes regimes that are more favourable for sensing applications related to SBS – providing a valuable prediction tool for distributed sensing applications. In recent years, photonic computing has received considerable attention due to its numerous applications, such as high-speed optical signal processing, which would yield much faster computing times and higher bandwidths. For this reason, optical logic has been the focus of many research efforts and several schemes to improve conventional logic gates have been proposed. In view of this, a combined Brillouin gain and loss process has been proposed in a polarization maintaining optical fiber to realize all-Optical NAND/NOT/AND/OR logic gates in the frequency domain. A model describing the interaction of a Stokes, anti-Stokes and a pump wave, and two acoustic waves inside a fiber, ranging in length from 350m-2300m, was used to theoretically model the gates. Through the optimization of the pump depletion and gain saturation in the combined gain and loss process, switching contrasts of 20-83% have been simulated for different configurations.

Glacial-interglacial cycles drive changes in the discharge and sediment flux from the headwaters of glaciated basins, which are recorded by proglacial fluvial sediments. Linking braided river stratigraphy to the Quaternary climate record could indicate the control of climate-driven variations in discharge and sediment flux on fluvial processes, and the magnitude and frequency of past climate variations. New Zealand is a key location for investigating terrestrial records of Southern Hemisphere climate change. The Late Quaternary braided river deposits on the Canterbury Plains, South Island, New Zealand have formed over the last 400 ka. The coastal cliff marking the southeastern margin of the Canterbury Plains provides excellent exposure of fluvial sediments deposited during the last glacial period, from ~40 ka until the end of the Last Glacial Maximum (LGM) (~18 ka).Deposition at the modern coastline of the Canterbury Plains is interpreted in the context of the climate event stratigraphy for New Zealand, which requires a precise geochronology. This thesis demonstrates the first successful application of optically stimulated luminescence (OSL) dating to glaciofluvial sediments on South Island: a technique that was previously considered unsuitable for this region. Ages produced for the coastal stratigraphy range from 36.7 ± 2.9 to 18.2 ± 1.3 ka, indicating that deposition took place during the last glacial, with little or no postglacial aggradation. Three adjacent catchments on the southern Canterbury Plains - the Rakaia, Ashburton and Rangitata - have undergone glacial-drainage capture during the period represented by the coastal stratigraphy. During glacials, transfluent ice reversed the flow direction in several key tributaries, resulting in dramatic variations in effective drainage area of the Ashburton and Rangitata, and variations in discharge and sediment flux which are recorded in the stratigraphy of these catchments. The magnitude, timing and duration of drainage capture were quantified using the Plummer and Phillips (2003) glacier model. The Ashburton catchment increased to 160% of the modern effective drainage area when temperature change relative to modern conditions exceeded -6°C during the LGM. Meanwhile, the effective drainage area of the Rangitata decreased to 63%, and the Rakaia to 93%, reducing discharge from these catchments. Furthermore, glaciation dramatically affects the seasonality of the annual hydrograph. At four coastal sites, the fluvial stratigraphy was surveyed to investigate possible variations in depositional architecture, due to both climate variations, and glacial-drainage capture in the Ashburton and Rangitata. Unexpectedly, little vertical variation in depositional architecture was found, indicating that the deposits created by the braided rivers represent sediment transport during a similar set of flow (and by inference, climate) conditions. Laterally extensive erosional surfaces separating storeys of one or two flow depths in thickness, in combination with the OSL geochronology, suggest that the gravel-bed braided river stratigraphy primarily records a response to climate variations within glacial maxima, rather than on the scale of the glacial-interglacial cycle.

Orientadores: Vera Lúcia da Silveira Nantes Button, Marcelo Baptista de Freitas / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-28T09:42:26Z (GMT). No. of bitstreams: 1 Malthez_AnnaLuizaMetidieriCruz_D.pdf: 4070699 bytes, checksum: 5b502eb8b2975aac6052df7ad659d32a (MD5) Previous issue date: 2015 / Resumo: Neste estudo foi desenvolvido um dosímetro (monitor individual) para monitoração externa de indivíduos ocupacionalmente expostos à radiação (raios X e gama) que faz o uso simultâneo das técnicas de termoluminescência (TL) e luminescência opticamente estimulada (OSL - Optically Stimulated Luminescence), combinado às diferentes características dosimétricas de detectores já utilizados com a técnica TL na rotina dos Serviços de Monitoração Individual Externa (SMIEs) no Brasil (LiF:Mg,Ti ¿ TLD100, CaF2:natural, CaSO4:Dy - IPEN) e detectores utilizados com a técnica OSL, ainda pouco explorados na monitoração individual (BeO ¿ Thermalox 995) e recentemente autorizados a serem utilizados com a técnica OSL no país (Al2O3:C - Luxel). Para o desenvolvimento do monitor, diversas características intrínsecas e dosimétricas dos detectores empregando as técnicas TL e OSL em três diferentes equipamentos leitores foram avaliadas. Testes de desempenho foram aplicados ao monitor desenvolvido, conforme critérios estabelecidos no país e no exterior (CASEC e IEC, respectivamente). Os resultados obtidos demonstram que as respostas TL e OSL dos detectores dependem fortemente da configuração do leitor utilizado, da técnica empregada (TL ou OSL) e do tipo de sinal avaliado, no caso da técnica OSL (OSL total ou inicial). Assim é fundamental uma análise prévia de características intrínsecas do material, como comprimento de onda principal da emissão luminescente, tipo (inicial ou total) e magnitude (doses baixa, moderada ou alta) do sinal que será avaliado para a escolha adequada dos parâmetros do leitor (filtros, máscaras, potência, entre outros) empregando as duas técnicas. Os resultados obtidos com a técnica OSL reforçam seu uso na monitoração individual no Brasil, uma vez que estavam em acordo com a técnica TL, amplamente empregada pelos SMIEs nacionais. Além da determinação de dose individual, normalmente empregada na monitoração de trabalhadores, o dosímetro desenvolvido permite também estimar doses acumuladas ao longo do tempo, empregando a técnica OSL nos detectores de Al2O3:C ou BeO, sendo que no caso deste último, a dose única (ou individual) também pode ser determinada com a técnica TL aplicada simultaneamente no mesmo detector. Após a avaliação das respostas em energia dos detectores, um algoritmo foi desenvolvido, testado e validado para avaliar fatores de correção com respeito à energia, baseado na razão entre as respostas de um par de detectores TL e OSL. Os resultados demonstraram que as diferentes razões entre os sinais provenientes do par, permitem avaliar de forma precisa a qualidade da radiação à qual o par de detectores foi exposto. O monitor desenvolvido possui três configurações diferentes de pares de detectores, Al2O3:C/LiF:Mg,Ti, Al2O3:C/BeO e CaSO4:Dy/BeO. Ele apresenta como principais vantagens, em relação aos dosímetros já existentes em uso comercialmente, a possibilidade de poder inferir informações sobre a dose e qualidade da radiação (energia efetiva) sem a utilização de filtros e com diminuição das incertezas associadas, avaliar doses acumuladas ao longo do tempo com o mesmo dosímetro e combinar todas as características dos detectores associadas às técnicas TL e OSL, simultaneamente em um mesmo dosímetro. Os resultados dos testes de desempenho do monitor apresentaram conformidade com os critérios nacionais e internacionais estabelecidos, e contribuíram para que os critérios nacionais utilizados para a técnica TL possam ser estendidos para a técnica OSL / Abstract: In this study a dosimeter (personal monitor) for external monitoring of individuals occupationally exposed to radiation (X and gamma rays) was developed using simultaneously thermoluminescent (TL) and optically stimulated luminescence (OSL) techniques. Intrinsic characteristics of detectors already used with TL technique in External Individual Monitoring Services routine in Brazil (LiF:Mg,Ti ¿ TLD 100, CaF2:natural and CaSO4:Dy ¿ IPEN) were combined to detectors used with OSL technique, one less explored (BeO ¿ Thermalox 995), and other recently approved (Al2O3:C - Luxel) to be used in individual monitoring in the country (Al2O3:C - Luxel). During the monitor development, several intrinsic and dosimetric characteristics of detectors were evaluated employing TL and OSL techniques in three different reader equipments. Performance tests were applied to the developed monitor according to national and international established criteria (CASEC and IEC, respectively). The obtained results showed that the responses of TL and OSL detectors are strongly dependent on reader configuration, employed technique (TL and OSL) and, in the particular case of OSL technique, also the signal (total or initial OSL). Therefore, a previous analysis of the intrinsic characteristics of the material, as the main wavelength of the luminescent emission, the signal type (initial or total) and dose magnitude (low, moderate or high) must to be made in order to select the reader configuration (filters, power, and others) used with each technique. The results obtained with OSL technique reinforce its use in Brazil, as they were in agreement with TL technique, which is already largely used by national EIMS. In addition to the assess of individual dose, usually employed in workers monitoring, the developed dosimeter allows evaluating accumulated dose over time using OSL technique with Al2O3:C or BeO detectors, and single or individual doses can be evaluated applying TL technique simultaneously applied in the same detector. After the evaluation of the energy response of detectors, an algorithm was developed, tested and validated to assess correction factors with respect to energy, based on the ratio of the responses of a pair of TL and OSL detectors. The results confirm that the different ratios between signals from a detector pair allow to evaluate more accurately the radiation quality to that the pair of detectors were exposed. The monitor was developed with three different arrangements of pairs of detectors, Al2O3:C/LiF:Mg,Ti, Al2O3:C/BeO and CaSO4:Dy/BeO. It presents as main advantages, compared to existing commercial dosimeters in use, the possibility to infer information on the dosage and quality of radiation (effective energy) without the use of filters and reducing associated uncertainties, to assess cumulative doses over time with the same dosimeter, and to combine all features of the detectors associated with TL and OSL techniques, simultaneously, in the same dosimeter. The results of the performance tests of the developed monitor were in accordance to national and international criteria, and contributed to that the national criteria, used for TL technique, can also be extended to the OSL technique / Doutorado / Engenharia Biomedica / Doutora em Engenharia Elétrica

OBJECTIVE: Type 2 diabetes (T2D), the most common type of diabetes characterized by high blood glucose and insulin resistance, results from both genetic and environmental factors. Our lab has proposed that chronic excess nutrients induce insulin hypersecretion from the pancreatic ß-cell, contributing to hyperinsulinemia, a prequel to T2D. Normal glucose-stimulated insulin secretion (GSIS) is oscillatory, a feature that is lost in patients with T2D. In this thesis we examine the oscillatory secretion profiles of clonal pancreatic ß-cells cultured in normal and excess nutrients that mimic conditions of T2D. We also begin to examine oscillations in protein phosphorylation that may contribute to normal ß-cell metabolism and GSIS, but if altered might potentially lead to impaired insulin secretion. METHODS: Nutrient regulation of oscillatory insulin release was studied in clonal pancreatic β-cells (INS-1) cultured in multiwell plates in both low (4 mM) and high (11 mM) glucose. Insulin secretion was stimulated in cells from multiwell plates one well at a time at 30 sec intervals and sampled simultaneously at the end of the timecourse. Insulin secretion and insulin content were measured using a homogenous time-resolved fluorescence (HTRF) insulin kit (Cisbio). Protein was extracted from these same cells for analysis of time-dependent phosphorylation by western blot using specific antibodies. Protein phosphorylation was detected using SuperSignal West Femto chemiluminescence reagent (ThermoFisher) and imaged on an iBright Imaging System (Invitrogen). RESULTS: Insulin secretion from INS-1 cells grown in separate plates and in 4 mM glucose oscillated with a period of 8.2  0.5 min compared to 5.0  0.5 min in cells cultured at 11 mM glucose. The amplitude of oscillations was 40.4  11.5 and 14.6  1.5 for cells cultured in 4 and 11 mM glucose respectively. Oscillations in secretion from cells cultured in 4 and 11 mM glucose in the same plate were not different in period but different in amplitude due in part to reduced insulin content. Oscillation in the phosphorylation patterns of acetyl-CoA carboxylase (ACC) and myristoylated alanine rich C kinase substrate (MARCKS) were measured in cells cultured in 4 mM glucose and both exhibited a peak in phosphorylation that occurred at the nadir of the insulin oscillation between peaks of insulin release. CONCLUSION: Insulin secretion from pancreatic ß-cells is affected by nutrient status as excess nutrients decrease the amplitude of oscillations in insulin release. The period of oscillations can also be affected. Oscillations in protein phosphorylation are consistent with both ACC and MARCKS contributing to normal GSIS. These initial studies provide evidence of the suitability of this model system to correlate oscillations in protein activity to exocytosis. Future studies focused on the effects of low and high glucose will potentially reveal new important therapeutic targets that may help prevent/reverse/ameliorate insulin hypersecretion leading to insulin resistance and T2D.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20616号 / 医博第4265号 / 新制||医||1023(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 長船 健二, 教授 渡邊 直樹, 教授 岩田 想 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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京都大学 / 新制・課程博士 / 博士(生命科学) / 甲第24749号 / 生博第490号 / 新制||生||65(附属図書館) / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 石川 冬木, 教授 高田 穣, 教授 朝長 啓造 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

Surface plasmon-polaritons are optical surface waves formed through the interaction of photons with free electrons at the surface of metals. They offer interesting applications in a broad range of scientific fields such as physics, chemistry, biology, and material science. However, many of such applications face limitations imposed by the high propagation losses of these waves at visible and near-infrared wavelengths, which result mainly from power dissipation in the metal. In principle, the propagation losses of surface plasmon-polaritons can be compensated through optical amplification. The objective of this thesis is to provide deeper insights on the physics of surface plasmon-polariton amplification and spontaneous emission in surface plasmon-polariton amplifiers through theoretical and experimental vehicles applied (but not necessarily restricted) to a particular plasmonic mode termed long-range surface plasmon-polariton. On the theoretical side, the objective is approached by developing a realistic theoretical model to describe the small-signal amplification of surface plasmon-polaritons in planar structures incorporating dipolar gain media such as organic dye molecules, rare-earth ions, and quantum dots. This model takes into account the inhomogeneous gain distribution formed near the metal surface due to a non-uniform excitation of dipoles and due to a position-dependent excited-state dipole lifetime that results from near-field interactions between the excited dipoles and the metal. Also, a theoretical model to describe the amplified spontaneous emission of surface plasmon-polaritons supported by planar metallic structures is developed. This model takes into account the different energy decay channels into which an exited dipole located in the vicinity of the metal can relax. The validity of this model is confirmed through experimentation. On the experimental side, the objective is approached by providing a direct experimental demonstration of complete loss compensation in a plasmonic waveguide. The experiments are conducted using the long-range surface plasmon-polariton supported by a symmetric thin gold waveguide incorporating optically pumped organic dye molecules in solution as the gain medium. Also, an experimental study of spontaneous emission in a long-range surface plasmon-polariton amplifier is presented. It is shown that this amplifier benefits from a low spontaneous emission into the amplified mode, which leads to an optical amplifier with low noise characteristics. The experimental setup and techniques are explained in detail.

Nina Andersson (2014) Läsning i särskolan – ur ett elevperspektiv.Speciallärarprogrammet 90hp, Skolutveckling och ledarskap,Lärande och samhälle, Malmö HögskolaProblemområde: Undervisningen i särskolan har fått kritik för att det är för mycket fokus på omsorg istället för kunskap. Därför är det av stor vikt att belysa undervisningen i särskolan och se i fall den bilden stämmer. Att fånga elevers syn på något och i synnerhet elever med utvecklingsstörning är inte särskilt vanligt därför är min bestämda uppfattning att det är viktigt att den här gruppens röster blir hörda. För att få en bakgrund och förståelse av elevernas kontext är min avsikt att beskriva deras svenskundervisning under ett antal lektioner.Syfte: Syftet är att undersöka grundsärskoleelevers upplevelser och erfarenheter av läsning och svenskundervisning. Vidare vill jag genom observation belysa hur svenskundervisningen kan se ut i två grundsärklasser på högstadiet. Undersökningens frågeställningar är: Hur upplever åtta grundsärskoleelever sin läsning och svenskundervisning?  Hur kan ett fåtal lektioner svenskundervisning beskrivas i två grundsärskoleklasser?Teoretisk ram: Studiens teoretiska ramverk är det sociokulturella perspektivet, vilket ses som en övergripande teori för lärande, kommunikation och har en interaktiv syn på läsförståelse. Jag belyser även metakognition och läsförståelseundervisning utifrån detta perspektiv.Metod: För att fånga elevernas perspektiv på läsning använder jag mig av intervju som metod. Med hjälp av videosekvenser, sk stimulated recall, underlättas berättandeti intervjusituationen. Genom observation, både filmat material och fältanteckningar, beskrivs två grundsärklassers svenskundervisning under ett fåtal lektioner.Resultat med analys: I de båda verksamheterna är pedagogerna ett stort stöd i elevernas lärandeprocess. Tydliga exempel ges på att pedagogerna försöker öka elevernas omvärldskunskap, vilket kan leda till en större förståelse. I svenskundervisningen får eleverna möta och producera texter av olika slag. Elevernas perspektiv på läsning har jag delat upp i tre teman. Läsning på fritiden: Fyra av eleverna tycker om att läsa på sin fritid, en tycker om att läsa ibland medan resterande tre inte tycker om att läsa på sin fritid. De flesta eleverna minns sin favoritbok från uppväxten. Två av eleverna läser gärna för sina småsyskon. Familj och syskon spelar en viktig roll i elevernas möte med textvärlden.Läsning i skolan: Flera av eleverna minns svårigheter i sin tidiga läsning. Vidare berättar de om problem att läsa, förstå och uttala ord. Några av eleverna har dock strategier för hur de ska lösa svårigheterna, vilket tyder på metakognitiva förmågor. Flertalet elever uttalar sig positivt om svenskundervisningen.Läsning i framtiden: Samtliga elever inser vikten av att kunna läsa och ger exempel på olika scenarion som kan inträffa då man inte kan läsa. Eleverna har tankar och idéer om vad de vill arbeta med i framtiden, frågan är om det är möjligt med dagens tuffa arbetsmarknad där unga vuxna med olika funktionshinder lätt hamnar utanför?Kunskapsbidrag: Studien visar en varierad svenskundervisning där eleverna får möta och producera olika texter. Tas kunskapsuppdraget mer på allvar i dagens särskola eller är det en balans mellan kunskap och omvårdnad som råder? Elevernas röster bidrar till att öka kunskapen kring lärande och läsning i grundsärskolan.Specialpedagogiska implikationer: Som speciallärare är det viktigt att ta del av elevernas erfarenheter och upplevelser kring lärande och läsning. Genom reflektion kan jag förhoppningsvis bryta gamla tankemönster och börja utveckla nya. / Title: Reading in Specialschool – a students perspective Author: Nina AnderssonBackground: The education in Specialschools has been criticised for too much focus on care instead of knowledge. Consequently it is of importence to illustrate the education in Specialschool to see if that image is true. To capture students perspective, especially students with intellectual disabilities, is not very common and therefore I think it is very important that the voices of this group can be heard. To acquire a background and understanding of the students’ context their Swedish education will be described during a short time.Aim: The thesis aims to examine Specialschools students experiences of reading. Observation highlights how the education in Swedish can be described in two secondary classes of Specialschool. The examination is based on the two questions: How do eight Specialschool students view reading and education in Swedish? In a limited time: How is the education in Swedish in two Specialschool classes described?Theory: The theoretical framework of the thesis is the sociocultural perspective, which is an overall theory for learning, communication and has an interactive approach of reading comprehension.Metacognition and teaching of reading comprehension are also described from this perspective.Method: To capture the students’ perspective on reading qualitative interviews are used. Via videosequences, stimulated recall, the storytelling eases in the interviewsituation.Through observation, both video material and field notes two Specialschools classes education in Swedish are described.Results and Analysis: The teachers are a great support in the students learning process. Clear examples of teachers trying to increase the students outside world knowledge are given. In the Swedish education the students meet and produce different kinds of texts. The students’ perspectives on reading are grouped under three themes:During leisure time: Four of the students like to read on their leisure time, one likes to read sometimes while 3 do not like to read. Most students remember their favourite book from growing up. Two students like reading to their younger siblings. Family play an important role in the students’ encounter with texts.In school: Most students remember difficulties in their early reading. They mention problems to read, understand and articulate words. Some students have strategies how to salve the difficulties, which suggests metacognitive skills. Most students speak positively about the Swedish education.In the future: All students realise the importance of being able to read and examples of different scenarios that can occur when one can not read are given. The students have thoughts and ideas about they would like to work with in the future. The question is if it is possible with the current labour market where many young people with different functional disabilities remain outside?Contribution of the thesis: The study shows a varied Swedish education where the students meet and produce different types of texts. Is the commitment of knowledge more seriously taken or is it a balance between knowledge and care? The students voices contribute to increase the knowledge on learning and reading in specialschool.