• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 9
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 34
  • 7
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 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.
31

PPRs and cpRNPs

Ruwe, Hannes 10 July 2015 (has links)
Die Genexpressionsmaschinerie in Chloroplasten und Mitochondrien und die ihrer prokaryotischen Vorläufer sind konserviert. Innerhalb eines bakteriellen Grundgerüsts entwickelte sich darüber hinaus ein komplexer RNA-Metabolismus. In der vorliegenden Arbeit wird eine neue Klasse kleiner RNAs (15-50nt) mit plastidärem und mitochondrialen Ursprung beschrieben. Diese kurzen RNAs überlappen mit Bindestellen von RNA-bindenden Proteinen, die mRNAs gegen exonukleolytischen Verdau beschützen. Diese stabilisierende Funktion wird vermutlich hauptsächlich von PPR (Pentatricopeptid repeat) Proteinen und verwandten Proteine bewerkstelligt. Die kleinen RNAs repräsentieren dabei minimale nuklease-resistente Bereiche, sogenannte RNA-Bindeprotein footprints. Solche footprints finden sich in fast jedem intergenischen Bereich, der Prozessierung aufweist. Durch transkriptomweite Untersuchungen von kleinen RNAs in Mutanten von RNA-Bindeproteinen konnte für diese eine Reihe von Bindestellen identifiziert werden. Nuklease-resistente kleine RNAs fehlen in entsprechenden Mutanten. Der Vergleich neu identifizierter Ziele einzelner RNA-Bindeproteine führte dabei zu neuen Erkenntnissen über den Mechanismus der RNA-Erkennung durch PPR Proteine. Im Gegensatz zu Plastiden befinden sich kleine RNAs in Mitochondrien überwiegend an den 3‘ Enden von Transkripten, deren Stabilität vermutlich maßgeblich von diesen RNA-Bindeproteinen beeinflusst wird. Für das chloroplastidäre Ribonukleoprotein CP31A konnte gezeigt werden, dass es an der Stabilisierung der ndhF mRNA beteiligt ist. Die Interaktion mit der ndhF mRNA, die eine zentrale Komponente des NDH-Komplexes kodiert, wird dabei über die 3‘ untranslatierte Region vermittelt. Zusätzlich konnte gezeigt werden, dass CP31A die Stabilität einiger antisense Transkripte beeinflusst. Weiterhin wurden zehn neue Cytidin Desaminierungungen durch die Analyse von RNA-Seq Datensätzen in der Modellpflanze Arabidopsis thaliana identifiziert. / Chloroplasts and mitochondria are of endosymbiotic origin. Their basic gene expression machineries are retained from their free-living prokaryotic progenitors. On top of this bacterial scaffold, a number of organelle-specific RNA processing steps evolved. In this thesis, a novel class of organelle-specific short (15-50nt) RNAs is described on a transcriptome-wide scale. The small RNAs are found at binding sites of PPR (Pentatricopeptide repeat) and PPR-like proteins, which protect mRNAs against exonucleolytic decay. The small RNAs represent minimal nuclease resistant RNAs, so called PPR footprints. Small RNAs were identified in almost every intergenic region subjected to intergenic processing. This finding suggests that accumulation of processed transcripts in plastids is mostly due to protection by highly specific RNA-binding proteins. Small RNA sequencing identified a number of nuclease insensitive sites missing in mutants of RNA-binding proteins. Analysis of multiple small RNAs representing target sites of single PPR proteins expands the knowledge of target specificity. In mitochondria, accumulations of small RNAs predicts that at least two thirds of mitochondrial mRNAs are stabilized by RNA-binding proteins binding in their 3’UTR. In sum, small organellar RNAs turned out to be instrumental in elucidating the hitherto enigmatic intercistronic processing of organellar RNAs and allowed novel insights into the function of the dominant family of organellar RNA binding proteins, the PPR proteins. A chloroplast ribonucleoprotein CP31A is shown to be involved in stabilization of an mRNA for a central component of the NDH-complex by interaction with its 3’UTR. In addition, CP31A represents the first factor described that influences the accumulation of chloroplast antisense transcripts. Finally, ten novel plastid C to U RNA-editing sites were identified in the model plant Arabidopsis thaliana, using a novel RNA-Seq based approach.
32

O hist?rico de uma pesca tropical utilizando indicadores ecossist?micos

Rato, M?rcio Luiz Farias 11 February 2014 (has links)
Made available in DSpace on 2014-12-17T14:33:10Z (GMT). No. of bitstreams: 1 MarcioLFR_DISSERT.pdf: 949735 bytes, checksum: 7b0d7914f06ce721cd7df5864b67525c (MD5) Previous issue date: 2014-02-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / When scientists study methods, theory and standards in an inseparable form, he is facing a paradigm. Throughout the development of a determined science, paradigms can change by changing the methods, objective and standards of research. Fisheries science is changing the paradigm moving from the paradigm of maximization in the use of resources, quantified by the index of the catch, which was influenced by evolutionary concepts such as Optimal Foraging Theory, to the sustainability paradigm that seeks its foundation in the fishery ecosystem perspective. The goal of this study was to review methods, theory and the history of ecosystem indexes of fishery science that attempts to determine sustainability of fishery resources from the data capture. Ecosystems indexes by themselves may not be useful to measure the sustainability of fishing because they focus only on the environmental or ecological side of the sustainability tripod. Probably to measure the sustainability of fishing these indexes should include in the future the Payments for Ecosystem Services and Social Resilience. Thus the methods and theories are in constantly changing within science to meet the most current paradigm / Quando o cientista enxerga de forma insepar?vel os m?todos, a teoria e as normas ele est? diante de um paradigma. Ao longo do tempo o desenvolvimento de uma determinada ci?ncia o paradigma pode mudar alterando os m?todos, os objetivos e as normas da pesquisa com o passar dos anos. Ci?ncia Pesqueira transitou de paradigma da maximiza??o na utiliza??o dos recursos, quantificada pelo ?ndice da captura, que foi influenciado por conceitos evolutivos como a Teoria do Forrageamento ?timo para um paradigma da sustentabilidade que busca seu alicerce na perspectiva ecossist?mica da pesca. O objetivo desse trabalho foi realizar uma revis?o que aborda m?todos, teoria e o hist?rico dos ?ndices ecossist?micos da ci?ncia pesqueira que tentam determinar a sustentabilidade dos recursos pesqueiros a partir dos dados de captura. Os ?ndices ecossist?micos talvez n?o consiga mensurar a sustentabilidade da pesca por si s?, porque eles abordam apenas o lado ambiental ou ecol?gico do trip? da sustentabilidade. Provavelmente para se mensurar a sustentabilidade da pesca esses ?ndices devem se juntar no futuro com os Pagamentos por Servi?os Ecossist?micos e a Resili?ncia Social. Assim os m?todos e as teorias se agregam e se reformulam constantemente dentro dessa ci?ncia para atender o paradigma mais atual
33

Language Identification Through Acoustic Sub-Word Units

Sai Jayram, A K V 05 1900 (has links) (PDF)
No description available.
34

Chování investorů v Pražské památkové rezervaci / The Behaviour of Investors in Prague Historic Reservation

Adensamová, Fay January 2012 (has links)
The current situation in the historic centre of Prague does not allow for interference in the behaviour of investors. The tools for protection of Prague Historic Reservation are insufficient. Much of the real estate is not used and becomes ruins, resulting in an irreplaceable cultural and social, but also economic loss to the Prague Historical Reservation which is on the UNESCO World Cultural and Natural Heritage List. The aim of this thesis is to analyse the current state of Prague Historic Reservation as well as to suggest possible solutions. Analyses, own research, interviews and statistics have been used to prove the situation. There is a part of the thesis comparing the current state with other cities abroad (e.g. Vienna, Dresden, Cologne, Paris).

Page generated in 0.038 seconds