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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.
231

Formation and evolution of globular clusters in the Galaxy and Magellanic Clouds / Formação e evolução de aglomerados globulares da Galáxia e Nuvens de Magalhães

Bruno Moreira de Souza Dias 25 June 2014 (has links)
Globular clusters are tracers of the formation and evolution of their host galaxies. Kinematics, chemical abundances, age and position of the clusters allows tracing interactions between Milky Way and surrounding galaxies and outlines their chemical enrichment history. In this thesis we analyse mid-resolution spectra of about 800 red giant stars in 51 Galactic globular clusters. It is the first time that [Fe/H] and [Mg/Fe] derived in a consistent way are published for such a huge sample of globular clusters, almost 1/3 of the total number of catalogued clusters. Our metallicities are showed to be more precise than previous works based on mid-resolution spectroscopy. A turnover at [Fe/H] ~ -1.0 is found in the plot [Fe/H] vs. [Mg/Fe] for bulge and halo, although bulge seems to have a more metal-rich turnover, i.e, bulge has more efficient formation than the halo. Comparing the abundances with age the timescale for SNIa to start to become important is 1Gyr. [Fe/H] vs. age corroborates the different star formation efficiency of bulge and halo while [Mg/Fe] does not follow that. Halo was formed in mini halos or dwarf galaxies, and two multiple population clusters had their origin analysed to check it. M 22 seems to have been formed in the Milky Way while NGC 5824 possibly was originated in a dwarf galaxy, although our results are inconclusive for NGC 5824. The Galactic bulge seems to have been formed fast i.e., probably the oldest globular cluster is there. In fact HP 1 has a bluer horizontal branch than expected for its metallicity and we interpret that as an age effect. We determine its distance using light curves of variable stars in order to constrain future age determinations via colour-magnitude diagram. Finally, we investigate interaction between Milky Way and its neighbour galaxy SMC. We find that some star clusters are being stripped out of the SMC main body, which is consistent with tidal stripping scenario for the interaction between the galaxies, instead of ram pressure that would only affect gas. / Aglomerados globulares são traçadores da formação e evolução de suas galáxias. Cinemática, abundâncias químicas, idades e posições dos aglomerados permitem traçar interações entre Via Láctea e galáxias vizinhas e suas histórias de enriquecimento químico. Nesta tese analisamos espectros de média resolução de mais de 800 estrelas gigantes vermelhas em 51 aglomerados globulares Galácticos. É a primeira vez que [Fe/H] and [Mg/Fe] determinados de modo consistente são publicados para uma amostra desse porte, ~1/3 dos objetos catalogados. Nossas metalicidades são mais precisas que trabalhos anteriores similares. Uma quebra em [Fe/H] ~ -1.0 é encontrada no gráfico [Fe/H] vs. [Mg/Fe] para o bojo e halo, embora bojo parece ter uma quebra em [Fe/H] maior, i.e, bojo tem formaçãao mais eficiente que o halo. Comparando abundâncias com idade, a escala de tempo para SNIa ficar importante é 1Gano. [Fe/H] vs. idade corrobora diferentes eficiências de formação do bojo e halo, mas [Mg/Fe] vs. idade não mostra isso. O halo foi formado em mini halos ou galáxias anãs, e dois aglomerados com dispersão em [Fe/H] tiveram suas origens analisadas. M 22 parece ter sido formado na Via Láctea e NGC 5824 possivelmente foi originado em uma galáxia anã, embora os resultados são inconclusivos para NGC 5824. O bojo parece ter sido formado rapidamente e deve possuir o aglomerado mais velho. De fato, HP 1 tem um ramo horizontal mais azul que o esperado para sua metalicidade e vemos isso como um efeito da idade. Determinamos sua distância usando curvas de luz de RR Lyrae de maneira a restringir futuras determinações de idade via diagrama cor-magnitude. Finalmente, investigamos a interação entre Via Láctea e sua galáxia vizinha SMC. Encontramos aglomerados sendo removidos do corpo central da SMC, consistente com cenário de remoção por força de maré para a interação entre as galáxias, em vez de ``ram pressure\'\' que afeta só gás.
232

Professionalitetens gränser : Socialsekreterares erfarenheter av unga vuxna klienter med komplexa behov inom socialtjänst–ekonomiskt bistånd

Han, Kilsoo January 2020 (has links)
This study explores the experiences of the Swedish front-line social workers (socialsekreterare) in the municipal income support unit, Young Adults, monthly assessing the income support applications as well as daily processing the activation programs for young adult clients with mental ill-health combined with social-medicinal vulnerabilities, also referred to as young adults with complex needs. Furthermore, this study aims to illuminate the ever changing conditions of the Swedish welfare state and its underlying driving forces through the lens of the social workers. 9 Semi-structured distance interviews with 11 social workers from 6 municipalities belonging to 5 regions in Sweden, were conducted for the collection of qualitative data. It has been analyzed by the inductive-deductive coding as well as a theoretical frame consisting of concepts such as discretiona and advocacy of M. Lipsky, and reciprocal interaction (Wechselwirkung), form and contents, and call of G.Simmel. The result and analysis show that the rehabilitative approach based on the interactions and relations with the clients, is prevalent through the social workers’ processing of the activation program. It seems to be effective in a dyad, between the social workers and the client while the social workers’ discretion is maximized for the utilization of the agency (unit) activation resources. However, it proved not to be as effective in a triad or more when an extern agent outside of the unit, Young Adults begins to be involved. The tension is a fact and the social workers’ discretion is minimized when they have to process the activation program for the clients who are neither “active enough” to have a job in the ordinary labor market, nor “sick enough” to be eligible for the stately activity compensation (aktivitetsersättning) from the Social Insurance Agency (Försäkringskassan) which heavily relies on the medicinal expertise for its decision making. The social workers’ experience to fail to deliver the best possible results out of the activation programs, and the client relationship built on the rehabilitative approach turns out to be unsustainable, which can indicate the discrepancy between the rehabilitative approach as well as the activation programs, as content, and the unit, Young Adults, as form. Even though the social workers daily carry the ideological as well as the social-political tensions between the medicalization and the activation through the ever changing reality of the Swedish welfare state, their mandate to make an impact on the decision making of the activity compensation program, is rather limited, reflecting the Swedish welfare state’s expectation for the professionalism of the social workers. Rather striking that the social workers, however, confess that they in spite of the pressure of organizational efficiency as well as socio-economic discourse of digitalization undermining the concept of the unit, Young Adults, are not willing to give up the rehabilitative approach for the client’s sake but also to protect their unit, Young Adults, which postulate that they are not the gatekeepers in the agency but the advocate for the clients. In this moment, they also seem to know, and even have the call, the essential, if not mandatory, element needed to be landed in the perfect society of G. Simmel.
233

Automatic Speech Recognition and Machine Translation with Deep Neural Networks for Open Educational Resources, Parliamentary Contents and Broadcast Media

Garcés Díaz-Munío, Gonzalo Vicente 25 November 2024 (has links)
[ES] En la última década, el reconocimiento automático del habla (RAH) y la traducción automática (TA) han mejorado enormemente mediante el uso de modelos de redes neuronales profundas (RNP) en constante evolución. Si a principios de los 2010 los sistemas de RAH y TA previos a las RNP llegaron a afrontar con éxito algunas aplicaciones reales como la transcripción y traducción de vídeos docentes pregrabados, ahora en los 2020 son abordables aplicaciones que suponen un reto mucho mayor, como la subtitulación de retransmisiones audiovisuales en directo. En este mismo período, se están invirtiendo cada vez mayores esfuerzos en la accesibilidad a los medios audiovisuales para todos, incluidas las personas sordas. El RAH y la TA, en su estado actual, son grandes herramientas para aumentar la disponibilidad de medidas de accesibilidad como subtítulos, transcripciones y traducciones, y también para proporcionar acceso multilingüe a todo tipo de contenidos. En esta tesis doctoral presentamos resultados de investigación sobre RAH y TA basadas en RNP en tres campos muy activos: los recursos educativos abiertos, los contenidos parlamentarios y los medios audiovisuales. En el área de los recursos educativos abiertos (REA), presentamos primeramente trabajos sobre la evaluación y postedición de RAH y TA con métodos de interacción inteligente, en el marco del proyecto de investigación europeo "transLectures: Transcripción y Traducción de Vídeos Docentes". Los resultados obtenidos confirman que la interacción inteligente puede reducir aún más el esfuerzo de postedición de transcripciones y traducciones automáticas. Seguidamente, en el contexto del posterior proyecto europeo X5gon, presentamos una investigación sobre el desarrollo de sistemas de TA neuronal basados en RNP, y sobre sacar el máximo partido de corpus de TA masivos mediante filtrado automático de datos. Este trabajo dio como resultado sistemas de TA neuronal clasificados entre los mejores en una competición internacional de TA, y mostramos cómo estos nuevos sistemas mejoraron la calidad de los subtítulos multilingües en casos reales de REA. En el ámbito también en crecimiento de las tecnologías del lenguaje para contenidos parlamentarios, describimos una investigación sobre técnicas de filtrado de datos de habla para el RAH en tiempo real en el contexto de debates del Parlamento Europeo. Esta investigación permitió la publicación de Europarl-ASR, un nuevo y amplio corpus de habla para entrenamiento y evaluación de sistemas de RAH en continuo, así como para la evaluación comparativa de técnicas de filtrado de datos de habla. Finalmente, presentamos un trabajo en un ámbito en la vanguardia tecnológica del RAH y de la TA: la subtitulación de retransmisiones audiovisuales en directo, en el marco del Convenio de colaboración I+D+i 2020-2023 entre la radiotelevisión pública valenciana À Punt y la Universitat Politècnica de València para la subtitulación asistida por ordenador de contenidos audiovisuales en tiempo real. Esta investigación ha resultado en la implantación de sistemas de RAH en tiempo real, de alta precisión y baja latencia, para una lengua no mayoritaria en el mundo (el catalán) y una de las lenguas más habladas del mundo (el castellano) en un medio audiovisual real. / [CA] En l'última dècada, el reconeixement automàtic de la parla (RAP) i la traducció automàtica (TA) han millorat enormement mitjançant l'ús de models de xarxes neuronals profundes (XNP) en constant evolució. Si a principis dels 2010 els sistemes de RAP i TA previs a les XNP van arribar a afrontar amb èxit algunes aplicacions reals com la transcripció i traducció de vídeos docents pregravats, ara en els 2020 són abordables aplicacions que suposen un repte molt major, com la subtitulació de retransmissions audiovisuals en directe. En aquest mateix període, s'estan invertint cada vegada majors esforços en l'accessibilitat als mitjans audiovisuals per a tots, incloses les persones sordes. El RAP i la TA, en el seu estat actual, són grans eines per a incrementar la disponibilitat de mesures d'accessibilitat com subtítols, transcripcions i traduccions, també com una manera de proporcionar accés multilingüe a tota classe de continguts. En aquesta tesi doctoral presentem resultats d'investigació sobre RAP i TA basades en XNP en tres camps molt actius: els recursos educatius oberts, els continguts parlamentaris i els mitjans audiovisuals. En l'àrea dels recursos educatius oberts (REO), presentem primerament treballs sobre l'avaluació i postedició de RAP i TA amb mètodes d'interacció intel·ligent, en el marc del projecte d'investigació europeu "transLectures: Transcripció i traducció de vídeos docents". Els resultats obtinguts confirmen que la interacció intel·ligent pot reduir encara més l'esforç de postedició de transcripcions i traduccions automàtiques. Seguidament, en el context del posterior projecte europeu X5gon, presentem una investigació sobre el desenvolupament de sistemes de TA neuronal basats en XNP, i sobre traure el màxim partit de corpus de TA massius mitjançant filtratge automàtic de dades. Aquest treball va donar com a resultat sistemes de TA neuronal classificats entre els millors en una competició internacional de TA, i mostrem com aquests nous sistemes milloren la qualitat dels subtítols multilingües en casos reals de REO. En l'àmbit també en creixement de les tecnologies del llenguatge per a continguts parlamentaris, descrivim una investigació sobre tècniques de filtratge de dades de parla per al RAP en temps real en el context de debats del Parlament Europeu. Aquesta investigació va permetre la publicació d'Europarl-ASR, un corpus de parla nou i ampli per a l'entrenament i l'avaluació de sistemes de RAP en continu, així com per a l'avaluació comparativa de tècniques de filtratge de dades de parla. Finalment, presentem un treball en un àmbit en l'avantguarda tecnològica del RAP i de la TA: la subtitulació de retransmissions audiovisuals en directe, en el context del Conveni de col·laboració R+D+i 2020-2023 entre la radiotelevisió pública valenciana À Punt i la Universitat Politècnica de València per a la subtitulació assistida per ordinador de continguts audiovisuals en temps real. Aquesta investigació ha donat com a resultat la implantació de sistemes de RAP en temps real, amb alta precisió i baixa latència, per a una llengua no majoritària en el món (el català) i una de les llengües més parlades del món (el castellà) en un mitjà audiovisual real. / [EN] In the last decade, automatic speech recognition (ASR) and machine translation (MT) have improved enormously through the use of constantly evolving deep neural network (DNN) models. If at the beginning of the 2010s the then pre-DNN ASR and MT systems were ready to tackle with success some real-life applications such as offline video lecture transcription and translation, now in the 2020s much more challenging applications are within grasp, such as live broadcast media subtitling. At the same time in this period, media accessibility for everyone, including deaf and hard-of-hearing people, is being given more and more importance. ASR and MT, in their current state, are powerful tools to increase the coverage of accessibility measures such as subtitles, transcriptions and translations, also as a way of providing multilingual access to all types of content. In this PhD thesis, we present research results on automatic speech recognition and machine translation based on deep neural networks in three very active domains: open educational resources, parliamentary contents and broadcast media. Regarding open educational resources (OER), we first present work on the evaluation and post-editing of ASR and MT with intelligent interaction approaches, as carried out in the framework of EU project transLectures: Transcription and Translation of Video Lectures. The results obtained confirm that the intelligent interaction approach can make post-editing automatic transcriptions and translations even more cost-effective. Then, in the context of subsequent EU project X5gon, we present research on developing DNN-based neural MT systems, and making the most of larger MT corpora through automatic data filtering. This work resulted in a first-rank classification in an international evaluation campaign on MT, and we show how these new NMT systems improved the quality of multilingual subtitles in real OER scenarios. In the also growing domain of language technologies for parliamentary contents, we describe research on speech data curation techniques for streaming ASR in the context of European Parliament debates. This research resulted in the release of Europarl-ASR, a new, large speech corpus for streaming ASR system training and evaluation, as well as for the benchmarking of speech data curation techniques. Finally, we present work in a domain on the edge of the state of the art for ASR and MT: the live subtitling of broadcast media, in the context of the 2020-2023 R&D collaboration agreement between the Valencian public broadcaster À Punt and the Universitat Politècnica de València for real-time computer assisted subtitling of media contents. This research has resulted in the deployment of high-quality, low-latency, real-time streaming ASR systems for a less-spoken language (Catalan) and a widely spoken language (Spanish) in a real broadcast use case. / The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 287755 (transLectures), Competitiveness and Innovation Framework Programme (CIP) under grant agreement no. 621030 (EMMA), Horizon 2020 research and innovation programme under grant agreements no. 761758 (X5gon) and no. 952215 (TAILOR), and EU4Health Programme 2021–2027 as part of Europe’s Beating Cancer Plan under grant agreements no. 101056995 (INTERACT-EUROPE) and no. 101129375 (INTERACT-EUROPE 100); from the Government of Spain’s research projects iTrans2 (ref. TIN2009-14511, MICINN/ERDF EU), MORE (ref. TIN2015-68326-R,MINECO/ERDF EU), Multisub (ref. RTI2018-094879-B-I00, MCIN/AEI/10.13039/501100011033 ERDF “A way of making Europe”), and XLinDub (ref. PID2021-122443OB-I00, MCIN/AEI/10.13039/501100011033 ERDF “A way of making Europe”); from the Generalitat Valenciana’s “R&D collaboration agreement between the Corporació Valenciana de Mitjans de Comunicació (À Punt Mèdia) and the Universitat Politècnica de València (UPV) for real-time computer assisted subtitling of audiovisual contents based on artificial intelligence”, and research project Classroom Activity Recognition (PROMETEO/2019/111); and from the Universitat Politècnica de València’s PAID-01-17 R&D support programme. This work uses data from the RTVE 2018 and 2020 Databases. This set of data has been provided by RTVE Corporation to help develop Spanish-language speech technologies. / Garcés Díaz-Munío, GV. (2024). Automatic Speech Recognition and Machine Translation with Deep Neural Networks for Open Educational Resources, Parliamentary Contents and Broadcast Media [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/212454
234

Palynological studies and Holocene ecosystem dynamics in north western Khyber Pakhtunkhwa Province of Pakistan in the Hindu Kush Himalayan region / Trends of pollen grain size variation in C3 and C4 Poaceae species using pollen morphology for future assessment of grassland ecosystem dynamics / Vegetation and pollen along a 200 km transect in Khyber Pakhtunkhwa Province, north western Pakistan / Vegetation and climate dynamics in Khyber Pakhtunkhwa, north-western Pakistan, inferred from the Kabal Swat pollen record during the last 3300 years

Farooq, Jan 30 April 2015 (has links)
Khyber Pakhtunkhwa (31 ° 49'N, 70 ° 55'E bis 35 ° 50'N, 71 ° 47'E) liegt im Nordwesten Pakistans im Süden Asiens. Das Hindukusch-Gebirge in Afghanistan liegt im Westen, dem indischen Himalaya im Nordosten und die Karakorum Berge südlich vom tibetischen Hochland auf der Nordseite. Diese Arbeit besteht überwiegend aus drei separaten Studien entlang eines 200 km langen Transekts mit einem Höhengradienten ausgehend von den Sedimentbecken im Peshawar Tal (275 m ü.M.) bis hinauf zu den Malam Jabba Hills im Swat-Tal (2600 m ü.M.). Die erste Studie, die auf einer Datengrundlage von 160 Poaceae Arten beruht, zeigt Trends, dass polyploide C3- und C4-Poaceae-Arten größere Pollenkkörner als die jeweiligen diploiden Arten haben. In diesem Datensatz haben alle C4-Arten größere Pollenkörner als die C3-Arten. Ob Grassländer von C3 oder C4 Arten dominiert werden kann in verschiedenen Regionen und Lebensräumen durch die Untersuchung der Muster des Trends von zu- oder abnehmenden Pollenkorngrößen ermittelt werden. In unserem Datensatz ist Polyploidie bei C4-Gräsern häufiger als bei den C3 Arten. Die verwendete Methode kann auf Poaceae-Pollenkörner in Umweltarchiven angewendet werden, um das Klima der Vergangenheit zu rekonstruieren und die Dynamik der früheren Graslandökosysteme zu bewerten. Dieser Ansatz wird nicht nur bei laufenden paläoökologischen Studien helfen aufzuklären, wie die Änderungen der Vegetations-zusammensetzung und die Veränderungen in Biomen vergangener Graslandökosysteme zu entschlüsseln sind, sondern auch nützliche Erkenntnisse für die Vorhersage zukünftiger Entwicklungen ermöglichen. Die zweite Studie befasst sich mit modernen Pollenspektren aus Oberflächenproben und ihre Beziehung zu der umgebenden Vegetation, die nützliche Daten für die Interpretation von holozänen Pollenprofilen bietet. Dabei konnten entlang eines 200 km langen Höhengradienten vier verschiedene Höhenstufen unterschieden werden, wo die dominierenden Pflanzenfamilien, Poaceae, Asteraceae, Cyperaceae, Verbenaceae, Acanthaceae und Euphorbiaceae eine signifikante Korrelation mit dem gefunden Pollenniederschlag hatten, während sich bei anderen Familien, den Boraginaceae, Saxifragaceae, Apiaceae, Balsaminaceae und Rubiaceae große Unterschiede zu der zugehörigen Vegetationszusammensetzung ergaben. Für die Kalibrierung und Interpretation fossiler Pollendaten sollte also immer auch die aktuellen Beziehungen von Pollenniederschlag und Vegetationsdaten zumindest auf der Familienebene berücksichtigt werden. Die dritte Studie befasst sich mit einem Pollenprofil aus der Kabal Swat-Region, welches eine detaillierte Geschichte der Vegetation und des Klimas des Hindukuschs der letzten 3300 Jahre, also dem späten Holozäns enthält. Von 3300 bis 2400 cal BP, war eine subtropische semiaride krautige Vegetation hauptsächlich durch Cyperaceae- und Poaceae-Arten vertreten. Sie wurde ersetzt von gemischten Nadelwäldern mit Taxus, Pinus, sowie Juglans, Poaceae und Cyperaceae während der Zeit von 2400 bis 900 cal BP, was auf eine vergleichsweise moderate Klimaschwankung während des späten Holozäns weist. Der Rückgang der Poaceae von 2400 bis1500 cal BP und eine erneute Zunahme von 1500 bis 1200 cal BP Jahre zeigen, dass das Kabal Swat nass-kühlere und trocken-wärmere Phasen durchmachte. Nadelbäume in den gemischten Nadelwäldern treten heute bei größeren Höhe im alpinen Bereich auf. Weitere hochauflösende holozäne Pollenprofile des Hindukusch sind notwendig, um einen ausführlicheren Vergleich zu anderen süd- und zentralasiatischen Paläo-Archiven zu ermöglichen, die auch ein detaillierteres und anwendbares Wissen für Management und Naturschutzfragen ergeben.
235

Entwicklung von Monolithen auf Basis polyfunktioneller Glycidylether für die Anwendung in der Affinitätschromatographie

Pecher, Heike Susanne 28 March 2014 (has links)
Monolithische Phasen werden seit ca. 20 Jahren entwickelt und sind in den letzten Jahren eine attraktive Alternative zu etablierten mit Partikeln gefüllten Säulen geworden. Sie werden in anorganische Phasen und organische Polymermonolithe unterteilt. Monolithe bestehen aus einem einzigen, durchgehenden Stück. Charakteristisch ist das sie durchziehende Porennetzwerk, durch das der Eluent mit geringerem hydraulischen Widerstand fließen kann und das somit schnellere Flussraten ermöglicht. Polymermonolithe werden vorwiegend für die Separation großer Biomoleküle aufgrund eines durch Konvektion beschleunigten Massentransfers eingesetzt. Zudem sind sie über einen breiten pH-Wert-Bereich stabil und können direkt (in situ) im gewünschten Format polymerisiert werden. In der vorliegenden Arbeit gelang die Herstellung neuartiger epoxidbasierter Phasen nach einem von Weller et al. entwickelten Konzept, die im Affinitätsexperiment angewendet wurden. Die Herstellung erfolgte durch Autopolymerisation polyfunktioneller Glycidylether. Für die Funktionalisierung wurden nicht polymerisierte Epoxide genutzt. Als Monomere dienten TEPIC, GE 100 sowie GE 500. Die Arbeiten konzentrierten sich vor allem auf die bei Raumtemperatur durchführbaren Synthesen mit dem höher funktionellen GE 500. Die Polymerisationsbedingungen wurden hinsichtlich Porogenmischung und -anteil optimiert. Eine mit 75 Vol.-% Porogen (Dioxan/ MTBE (2:3)) hergestellte und mit rProtein A funktionalisierte Kapillarsäule (66 %, 12 µm, 7m2/g) ergab im Affinitätsexperiment eine Kapazität von 0,44 mg/mL aus Kaninchenserum isolierbarem IgG. Durch Beimischung von 60 % BDE konnte der Epoxidgehalt vervierfacht und die Porengröße auf 400 nm bei 59 % Porosität reduziert werden. Die spezifische Oberfläche wurde verdreifacht und die Kapazität präparierter Disks auf 0,90 mg/mL etwa verdoppelt. Die in dieser Arbeit entwickelten Disks können zur Isolierung von IgG aus einer komplexen Probe, wie beispielsweise Blutserum, eingesetzt werden. / Monolithic supports have been developed since 20 years and have become an attractive alternative to well-established columns packed with particles over the past years. They are classified into inorganic media and organic polymer monoliths. Monoliths consist of a single, continuous piece with an integrated characteristic porous network through which the eluent can flow with lower hydraulic resistance and which consequently offers higher flow rates. Due to an accelerated mass transfer caused by convection polymer monoliths are mainly used for separation of large biomolecules. In addition, they are stable over a wide pH range and can be polymerized directly (in situ) in the desired format. In the present work the successful preparation of new epoxide-based supports according to a concept introduced by Weller et al. as well as their application in affinity chromatography are reported. Their preparation was carried out by self-polymerization of polyfunctional glycidyl ethers and for functionalization non-polymerized epoxide groups were used. As monomers TEPIC, GE 100 and GE 500 were utilized. The work has focused especially on the polymerization of the higher functional GE 500, which can be perfomed at room temperature and was optimized in terms of both composition and amount of porogen. The extraction of IgG from rabbit serum with a capillary column (66 %, 12 µm, 7m2/g) prepared by 75 vol.-% porogen (dioxane/ MTBE (2:3)) and functionalized with rprotein A resulted in a capacity of 0,44 mg/mL. By addition of 60 % BDE the epoxide content was quadrupled and the pore size reduced to 400 nm while maintaining consistently high porosity of 59 %. The specific surface area was tripled and the capacity of prepared disks approximately doubled to 0,90 mg/mL. The disks developed in this work can be applied for the isolation of IgG from complex samples such as serum.
236

Hårdgörning av Asp / Densification of Aspen Wood

Johansson, Martin January 2008 (has links)
Hårdgörning av trä syftar till att göra materialet hårdare. Detta går att åstadkomma genom komprimering, det komprimerade materialet tenderar dock att återgå mot sin ursprungsform då materialet utsätts för fukt om ingen låsning sker. Låsningen kan ske mekaniskt i en treskiktskonstruktion som motverkar träets fuktrörelser. Dessa skivor har dock visat sig vara instabila och tidigare försök har uppvisat deformationer i form av kupning. Denna undersökning syftar till att utreda förutsättningarna för att använda komprimerad asp samt att ta fram underlag för framtagning av en kommersiell produkt. Praktiska tester har genomförts för att studera hårdhet, återfjädring och densitet hos det komprimerade virket. Vidare har treskiktsskivor tagits fram för att testa om det går att få en stabil konstruktion genom att variera tjockleken på spärrskiktet. Även skillnader i acklimatiseringstid och fuktkvotens inverkan för virkets återfjädring har studerats. Resultaten visar på att aspens hårdhet efter komprimering blir i samma nivå som bok och ask, en låg fuktkkvot vid komprimering av materialet ger en låg återfjädring, komprimerat material har en längre acklimatiseringstid till jämviktsfuktkvot och materialet går att låsa tvärs fiberriktningen i en treskiktskonstruktion. / To make wood harder it can be densified. This can be achieved by compression, the compressed material tends to return to the original shape when it is exposed to moisture fluxations and if no form of fixation occurs. The fixation can be done mechanically in a three-layer panel construction which reduce movements in the timber. These panels have been found to be unstable and previous attempts have shown deformations in form of cupping. This study aims to evaluate the conditions for using compressed aspen wood, and to provide a basis for development of a commercial product. Practical tests have been conducted to study hardness, springback and density of the compressed wood. In addition, three-layer panels have been developed to test whether it is possible to have a stable construction by varying the thickness of the buttom layer. Differences in acclimatisation time and the moisture contents effect on the springback has aslo been studied. The results show that the hardness of aspen wood after compression is in equal levels with beech and ashes, a low moisture contet provides a low springback, compressed timber have a longer time for acclimatisation and it is possible to fixate the material in the direction across the grain in a three-layer panel construction.
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Hårdgörning av Asp / Densification of Aspen Wood

Johansson, Martin January 2008 (has links)
<p>Hårdgörning av trä syftar till att göra materialet hårdare. Detta går att åstadkomma genom komprimering, det komprimerade materialet tenderar dock att återgå mot sin ursprungsform då materialet utsätts för fukt om ingen låsning sker. Låsningen kan ske mekaniskt i en treskiktskonstruktion som motverkar träets fuktrörelser. Dessa skivor har dock visat sig vara instabila och tidigare försök har uppvisat deformationer i form av kupning. Denna undersökning syftar till att utreda förutsättningarna för att använda komprimerad asp samt att ta fram underlag för framtagning av en kommersiell produkt.</p><p>Praktiska tester har genomförts för att studera hårdhet, återfjädring och densitet hos det komprimerade virket. Vidare har treskiktsskivor tagits fram för att testa om det går att få en stabil konstruktion genom att variera tjockleken på spärrskiktet. Även skillnader i acklimatiseringstid och fuktkvotens inverkan för virkets återfjädring har studerats.</p><p>Resultaten visar på att aspens hårdhet efter komprimering blir i samma nivå som bok och ask, en låg fuktkkvot vid komprimering av materialet ger en låg återfjädring, komprimerat material har en längre acklimatiseringstid till jämviktsfuktkvot och materialet går att låsa tvärs fiberriktningen i en treskiktskonstruktion.</p> / <p>To make wood harder it can be densified. This can be achieved by compression, the compressed material tends to return to the original shape when it is exposed to moisture fluxations and if no form of fixation occurs. The fixation can be done mechanically in a three-layer panel construction which reduce movements in the timber. These panels have been found to be unstable and previous attempts have shown deformations in form of cupping. This study aims to evaluate the conditions for using compressed aspen wood, and to provide a basis for development of a commercial product.</p><p>Practical tests have been conducted to study hardness, springback and density of the compressed wood. In addition, three-layer panels have been developed to test whether it is possible to have a stable construction by varying the thickness of the buttom layer. Differences in acclimatisation time and the moisture contents effect on the springback has aslo been studied.</p><p>The results show that the hardness of aspen wood after compression is in equal levels with beech and ashes, a low moisture contet provides a low springback, compressed timber have a longer time for acclimatisation and it is possible to fixate the material in the direction across the grain in a three-layer panel construction.</p>
238

Partner satisfaction and renewal likelihood in consumer supported agriculture (CSA) : a case study of The Equiterre CSA network

Achuo, George January 2003 (has links)
No description available.
239

Partner satisfaction and renewal likelihood in consumer supported agriculture (CSA) : a case study of The Equiterre CSA network

Achuo, George January 2003 (has links)
No description available.

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