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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

A NEW IMPLEMENTATION OF CLUSTERING ALGORITHM AND ITS APPLICATION IN NET-TREE CONSTRUCTION ALGORITHM

Dai, Yan 20 March 2009 (has links)
No description available.
12

Efeito da microgravidade simulada em fibroblastos de pele humana

Bellicanta, Patr?cia Lazzarotto 26 April 2016 (has links)
Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-05-04T16:56:07Z No. of bitstreams: 1 DIS_PATRICIA_LAZZAROTTO_BELLICANTA_COMPLETO.pdf: 1443666 bytes, checksum: 536295a41c399cfa2da6b360bf54a344 (MD5) / Made available in DSpace on 2017-05-04T16:56:07Z (GMT). No. of bitstreams: 1 DIS_PATRICIA_LAZZAROTTO_BELLICANTA_COMPLETO.pdf: 1443666 bytes, checksum: 536295a41c399cfa2da6b360bf54a344 (MD5) Previous issue date: 2016-04-26 / Introduction: The inherent characteristics of plasticity of human fibroblast cells makes it an important tool for evaluating the effects of microgravity at a cellular level. This study analyzed the behavior of human skin fragment fibroblasts in a simulated microgravity environment. Methods: Human fibroblast cells in the 8th and 17th passage, cultured under standard incubator conditions at 37? C with 5% CO2, were submitted to simulated microgravity in a 3D-clinostat for a period of 24h and 40h. After exposure, both passage cells were analyzed and compared with the control group (1G) in population doubling assays, tests of passage and microscopic analysis, as well as PCR analysis for detection of variations in the gene expression related to the cell cycle (p21, p16). Results: Before microgravity exposure, cells belonging to the 17th passage presented characteristics of cells in an apoptotic state. After 24h and 40h of microgravity, the cells of both groups showed themselves to be more confluent and elongated. PCR analysis demonstrated that p21 expression was decreased while p16 increased. In addition, PCR analysis showed a difference in expression of p21 and p16 genes between the 24h and 40h samples. Discussion: The present research showed cells to be more confluent and elongated after microgravity exposure, a characteristic of cells with fewer passages, suggesting alterations in their cytoskeleton. This result was confirmed by PCR analysis where a decrease in p21 expression was demonstrated. This result corroborates previous findings that among 588 genes tested, the p21 gene presented a negative expression. Conversely, the p16 gene showed a positive expression. Since both the p21 and p16 genes are related to the cell cycle, these results suggest the hypothesis of important changes having occurred in the cellular cytoskeleton and, consequently, a probable alteration in the production of cell cycle regulatory proteins (cyclins). Furthermore, RT-PCR analysis demonstrated a difference in p21 and p16 gene expression between the 24h and 40h samples, indicating the need for a more detailed comparison between the exposure times. Also pluripotency markers were found, Oct4 and Nanog, which suggests alterations in plasticity levels. / Introdu??o: As caracter?sticas da plasticidade inerentes das c?lulas de fibroblastos humanos os tornam uma ferramenta importante para avaliar os efeitos da microgravidade em um n?vel celular. Este estudo analisou o comportamento dos fibroblastos fragmento de pele humanas em um ambiente de microgravidade simulada. M?todos: c?lulas de fibroblasto humanos em 8a e 17a passagem, cultivadas em condi??es normais em incubadora a 37? C com 5% de CO2, foram submetidos ? microgravidade simulada em um clinostato-3D por um per?odo de 24h e 40h. Ap?s a exposi??o, as c?lulas de cada passagem foram analisadas e comparadas com o grupo de controle (1G) ensaios de prolifera??o celular (population doubling), ensaios de passagem e an?lise microsc?pica, bem como a an?lise de PCR para a detec??o de varia??es na express?o de genes relacionados com o ciclo celular (p21, p16). Resultado: Antes da exposi??o microgravidade, c?lulas pertencentes ? passagem 17? apresentaram caracter?sticas de c?lulas num estado apopt?tico. Depois de 24h e 40h de microgravidade, as c?lulas de ambos os grupos se mostraram mais confluentes e alongadas. A an?lise de PCR demonstrou que a express?o de p21 foi diminu?da enquanto p16 aumentou. Al?m disso, a an?lise PCR mostrou a diferen?a na express?o de genes p21 e p16 entre as amostras 24h e 40h. Discuss?o: A presente pesquisa mostrou que as c?lulas de 17? passagem tornaram- se mais confluentes e alongadas ap?s a exposi??o microgravidade, uma caracter?stica das c?lulas com menor n?mero de passagens, sugerindo altera??es no seu citoesqueleto . Este resultado foi confirmado por an?lise de PCR, onde foi demonstrado uma diminui??o na express?o de p21. Esse resultado confirma descobertas anteriores de que entre 588 genes testados, o gene p21 apresentou uma express?o negativa. Por outro lado, o gene p16 mostrou uma express?o positiva. Uma vez que ambos os genes P21 e P16 est?o relacionadas com o ciclo celular, estes resultados sugerem a hip?tese de altera??es importantes tenham ocorrido no citoesqueleto celular e, consequentemente, uma prov?vel altera??o na produ??o de prote?nas reguladoras do ciclo celular (ciclinas). Al?m disso, a an?lise de RT-PCR demonstrou uma diferen?a na express?o do gene p21 e p16 entre as amostras 24h e 40h, indicando a necessidade de uma compara??o mais detalhada entre os tempos de exposi??o. Foram tamb?m percebidas altera??es no n?vel de plasticidade dos fibroblastos de 17? passagem e 8? passagem, devido a express?o de marcadores de pluripot?ncia Oct4, Nanog.
13

THE AVATAR IN PANAMA: MODERN AND POSTMODERN DOUBLES AND DOUBLING IN ENRIQUE JARAMILLO LEVI’S WORLD OF DUPLICACIONES

MacLeod, Denise, denise.macleod@flinders.edu.au January 2009 (has links)
The concept of the double in literature has long enjoyed controversy. Originally, its purpose was to function purely as a comic device or to create an atmosphere conducive to the theme of mistaken identity. As the artistic and social milieu changed, the double came to embody unconscious desire in the form of a projected second self. Although its popularity as a theme seems to have waned in recent times, the double has re-emerged with a new twist as it has moved into the realm of postmodernism. Panamanian writer, Enrique Jaramillo Levi, has become synonymous with the concept although to date the theme has not been researched at all in its application to his work. This thesis deals with the treatment of this literary device in the work of Jaramillo Levi from a modern and postmodern perspective by using representative writers from around the world.
14

Fractionation Statistics

Wang, Baoyong 01 May 2014 (has links)
Paralog reduction, the loss of duplicate genes after whole genome duplication (WGD) is a pervasive process. Whether this loss proceeds gene by gene or through deletion of multi-gene DNA segments is controversial, as is the question of fractionation bias, namely whether one homeologous chromosome is more vulnerable to gene deletion than the other. As a null hypothesis, we first assume deletion events, on one homeolog only, excise a geometrically distributed number of genes with unknown mean mu, and these events combine to produce deleted runs of length l, distributed approximately as a negative binomial with unknown parameter r; itself a random variable with distribution pi(.). A biologically more realistic model requires deletion events on both homeologs distributed as a truncated geometric. We simulate the distribution of run lengths l in both models, as well as the underlying pi(r), as a function of mu, and show how sampling l allows us to estimate mu. We apply this to data on a total of 15 genomes descended from 6 distinct WGD events and show how to correct the bias towards shorter runs caused by genome rearrangements. Because of the difficulty in deriving pi(.) analytically, we develop a deterministic recurrence to calculate each pi(r) as a function of mu and the proportion of unreduced paralog pairs. This is based on a computing formula containing nested sums. The parameter mu can be estimated based on run lengths of single-copy regions. We then reduce the computing formulae, at least in the one-sided case, to closed form. This virtually eliminates computing time due to highly nested summations. We formulate a continuous version of the fractionation process, deleting line segments of exponentially distributed lengths in analogy to geometric distributed numbers of genes. We derive nested integrals and discover that the number of previously deleted regions to be skipped by a new deletion event is exactly geometrically distributed. We undertook a large simulation experiment to show how to discriminate between the gene-by-gene duplicate deletion model and the deletion of a geometrically distributed number of genes. This revealed the importance of the effects of genome size N, the mean of the geometric distribution, the progress towards completion of the fractionation process, and whether the data are based on runs of deleted genes or undeleted genes.
15

Subject Doubling in Spoken French

January 2012 (has links)
abstract: The purpose of this study is to explore the syntax and pragmatics of subject doubling in spoken French. Many prescriptivists have considered it a redundant and ungrammatical form, but over the years, it has gained more interest from syntacticians. It is widely acknowledged that dislocations involve topics, but the position of these structures is very disputed. Some linguists believe in base generation while others state there is movement. The status of subject clitics also comes into play and their role as arguments or agreement markers is crucial to understanding the issues at stake with a topic analysis. It is often argued that the clitics are undergoing a linguistic cycle whereby they lose their function of argument, and need to be reinforced by disjunct pronouns. In this study, I examined which analyses support my data and I attempted to determine what structures tend to be most dislocated by looking at the environment of the discourse in a corpus of spoken French. / Dissertation/Thesis / M.A. French 2012
16

Fractionation Statistics

Wang, Baoyong January 2014 (has links)
Paralog reduction, the loss of duplicate genes after whole genome duplication (WGD) is a pervasive process. Whether this loss proceeds gene by gene or through deletion of multi-gene DNA segments is controversial, as is the question of fractionation bias, namely whether one homeologous chromosome is more vulnerable to gene deletion than the other. As a null hypothesis, we first assume deletion events, on one homeolog only, excise a geometrically distributed number of genes with unknown mean mu, and these events combine to produce deleted runs of length l, distributed approximately as a negative binomial with unknown parameter r; itself a random variable with distribution pi(.). A biologically more realistic model requires deletion events on both homeologs distributed as a truncated geometric. We simulate the distribution of run lengths l in both models, as well as the underlying pi(r), as a function of mu, and show how sampling l allows us to estimate mu. We apply this to data on a total of 15 genomes descended from 6 distinct WGD events and show how to correct the bias towards shorter runs caused by genome rearrangements. Because of the difficulty in deriving pi(.) analytically, we develop a deterministic recurrence to calculate each pi(r) as a function of mu and the proportion of unreduced paralog pairs. This is based on a computing formula containing nested sums. The parameter mu can be estimated based on run lengths of single-copy regions. We then reduce the computing formulae, at least in the one-sided case, to closed form. This virtually eliminates computing time due to highly nested summations. We formulate a continuous version of the fractionation process, deleting line segments of exponentially distributed lengths in analogy to geometric distributed numbers of genes. We derive nested integrals and discover that the number of previously deleted regions to be skipped by a new deletion event is exactly geometrically distributed. We undertook a large simulation experiment to show how to discriminate between the gene-by-gene duplicate deletion model and the deletion of a geometrically distributed number of genes. This revealed the importance of the effects of genome size N, the mean of the geometric distribution, the progress towards completion of the fractionation process, and whether the data are based on runs of deleted genes or undeleted genes.
17

An Analysis of the Pedagogical Advantages Relating to Combined Study of Euphonium and Trombone through the Use of Specific Repertoire

Lipton, Jamie 08 1900 (has links)
Doubling is defined as playing two instruments. It is becoming increasingly necessary for low brass musicians to double in the course of their careers. Euphoniumists often learn trombone, and trombonists learn euphonium. The instruments share several surface similarities but also differ in many significant ways. Interviews with six professional doublers highlight strategies for learning, teaching, and performing on both trombone and euphonium. Slide and valve technique, adjustment of intonation, tone quality, air usage, repertoire, and skill maintenance are all addressed. Trombone literature comprises a large part of the euphonium repertoire, due to the fact that most trombone pieces can be performed on euphonium. Euphoniumists should avoid playing pieces that require glissandi or extremely loud dynamics to be effective. Euphonium solos are generally too technical to be practical for trombonists to perform. Grøndahl's Concert pour trombone et piano ou orchestre is a standard piece for both instruments. When performing the piece on either instrument, it is helpful to practice the piece on both trombone and euphonium in order to tap into each instrument's strengths.
18

High Efficiency High Power Blue Laser by Resonant Doubling in PPKTP

Danekar, Koustubh 08 1900 (has links)
I developed a high power blue laser for use in scientific and technical applications (eg. precision spectroscopy, semiconductor inspection, flow cytometry, etc). It is linearly polarized, single longitudinal and single transverse mode, and a convenient fiber coupled continuous wave (cw) laser source. My technique employs external cavity frequency doubling and provides better power and beam quality than commercially available blue diode lasers. I use a fiber Bragg grating (FBG) stabilized infrared (IR) semiconductor laser source with a polarization maintaining (PM) fiber coupled output. Using a custom made optical and mechanical design this output is coupled with a mode matching efficiency of 96% into the doubling cavity. With this carefully designed and optimized cavity, measurements were carried out at various fundamental input powers. A net efficie ncy of 81 % with an output power of 680 mW at 486 nm was obtained using 840 mW of IR input. Also I report an 87.5 % net efficiency in coupling of blue light from servo locked cavity into a single mode PM fiber. Thus I have demonstrated a total fiber to fiber efficiency of 71% can be achieved in our approach using periodically poled potassium titanyl phosphate (PPKTP). To obtain these results, all losses in the system were carefully studied and minimized.
19

A High Order Correction of the Energy of a One Dimensional Model of an H2+ Molecule

Humfeld, Keith Daniel 05 February 1999 (has links)
The ground state electron wavefunction of some molecules has a non-zero angular momentum about the internuclear axis. Molecular rotational momentum can couple with this angular momentum, splitting the energy degeneracy of the two directions of motion about the internuclear axis. Performing a Born-Oppenheimer approximation of such a system will break the relevant energy degeneracy at eighth order. This degeneracy breaking is known as L-doubling. / Master of Science
20

Die Untersuchung der replikativen Seneszenz kaniner dermaler Fibroblasten als Beitrag zur Alternsforschung

Streit, Susanne 19 December 2005 (has links)
Mit der vorliegenden Arbeit sollte nachgewiesen werden, dass bei in vitro kultivierten kaninen dermalen Fibroblasten einer Hunderasse nach einer bestimmte Kultivierungszeit replikative Seneszenz entsteht und dass das replikative Vermögen dieser Zellen in der Zellkultur abhängig vom Alter des Spendertieres ist. Dreißig Beagle aus zwei Versuchstieranstalten wurden als Hautspender genutzt. Diese Tiere wurden in die drei Altersgruppen jung, adult und alt unterteilt. Mit Hilfe einer Hautstanze wurde bei allen Tieren im Bereich der rechten Skapula ein Hautstück gewonnen. Diese Hautstücken wurden in Zellkulturflaschen verbracht. Die aus diesem Explantat auswandernden Zellen stellten die Grundlage für die Primärkultur dar. Die Zellen wurden in regelmäßigen Abständen subkultiviert. Dabei wurden immer die Gesamtzellzahl und die Vitalität der Kulturen bestimmt. Diese Werte bildeten die Grundlage für die Berechnung der Parameter des replikativen Vermögens der Zellen. Auf Grundlage der erstellten Wachstumskurven konnte die Generationszeit der Zellen berechnet werden. Parallel zur Kultivierung der Zellen erfolgte die morphologische Betrachtung der Zellen mit Hilfe eines Phasenkontrastmikroskops und histologischen Färbungen, die unter dem Lichtmikroskop näher beurteilt wurden. / This thesis aims to demonstrate that, after a certain period of time, replicative senescence develops in canine dermal fibroblasts of a certain dog breed when cultured in vitro. It is also shown that the replicative capacity of these cells is related to the age of the donor animal. Thirty Beagles from two experimental facilities were used as skin donors. The animals were divided in three age groups: young, adult and old. Skin samples from the right scapula were taken from all animals by means of a punch biopsy and transferred to cell culture vessels. The primary culture was based on the cells emigrating from these explants. The cells were subcultured at regular intervals, at which the total number of cells and the vitality of the cultures were also determined. Based on these parameters, the replicative capacity of the cells was calculated and growth curves were created, which were then used to calculate the generation times of the cells. Parallel to cultivation, the cells underwent morphological dissection using a phase contrast microscope on the one hand and a light-optical microscope with histological staining on the other hand.

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