• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 584
  • 118
  • 84
  • 74
  • 21
  • 16
  • 13
  • 9
  • 9
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • Tagged with
  • 1183
  • 491
  • 166
  • 162
  • 154
  • 141
  • 131
  • 99
  • 85
  • 84
  • 82
  • 77
  • 74
  • 72
  • 70
  • 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.
51

Database High Availability using SHADOW Systems

Pan, Xin January 2014 (has links)
Various High Availability DataBase systems (HADB) are used to provide high availability. Pairing an active database system with a standby system is one commonly used HADB techniques. The active system serves read/write workloads. One or more standby systems replicate the active and serve read-only workloads. Though widely used, this technique has some significant drawbacks: The active system becomes the bottleneck under heavy write workloads. Replicating changes synchronously from the active to the standbys further reduces the performance of the active system. Asynchronous replication, however, risk the loss of updates during failover. The shared-nothing architecture of active-standby systems is unnecessarily complex and cost inefficient. In this thesis we present SHADOW systems, a new technique for database high availability. In a SHADOW system, the responsibility for database replication is pushed from the database systems into a shared, reliable, storage system. The active and standby systems share access to a single logical copy of the database, which resides in shared storage. SHADOW introduces write offloading, which frees the active system from the need to update the persistent database, placing that responsibility on the underutilized standby system instead. By exploiting shared storage, SHADOW systems avoid the overhead of database-managed synchronized replication, while ensuring that no updates will be lost during a failover. We have implemented a SHADOW system using PostgreSQL, and we present the results of a performance evaluation that shows that the SHADOW system can outperform both traditional synchronous replication and standalone PostgreSQL systems.
52

An investigation into aspects of the replication of Jembrana disease virus

M.Stewart@murdoch.edu.au, Meredith Stewart January 2005 (has links)
Jembrana disease virus (JDV) is an acutely pathogenic lentivirus affecting Bali cattle in Indonesia. The inability to propagate the virus in vitro has made it difficult to quantitate JDV and determine the kinetics of virus replication during the acute disease process. Reported for the first time are 2 techniques that enable quantification of the virus, and the use of these techniques to quantify the virus load in plasma of cattle during the acute disease process. The 2 techniques were a qualitative one-step JDV real-time reverse-transcription polymerase chain reaction (qRT-PCR) assay for the detection and quantification of JDV RNA, and a JDV p26 capture ELISA for the detection and quantification of JDV capsid protein. The limit of detection of the qRT-PCR was 9.8 x 102 JDV viral RNA copies over 35 cycles, equivalent to 4.2 x 104 JDV genome copies/ml, and a peak virus load of 1.6 x 1012 JDV genome copies /ml during the acute febrile period. Viral RNA and JDV p26 levels were correlated in 48 plasma samples obtained from experimentally infected cattle. A significant positive correlation (R = 0.835 and r2 = 0.697) was observed between the 2 techniques within the range of their detection limits, providing a solid basis for the use of the economical capture ELISA to quantify JDV load when real-time PCR capability is not available. The detection of JDV p26 by capture ELISA was, however, much less sensitive than the real-time RTPCR with a detection limit equating to approximately 1 x 108 JDV genome copies/ml. The transcriptional pattern of JDV during the acute phase of infection was studied by RT-PCR, sequencing and northern blot analysis. Analysis revealed a complex pattern of transcription with the identification of 14 transcripts, which confirmed 6 predicted splice sites and the identified 7 splice sites not reported previously. A small 78 bp putative non-coding exon was identified that shared the same splice acceptor as vif and was associated with the alternative transcripts of tat, rev and env. Four tat, 3 rev and 2 env transcripts were identified. The rev and env transcripts were demonstrated to use the same splice site. The study confirmed that the production of a tmx transcript, a unique gene identified in the two bovine lentiviruses JDV and Bovine immunodeficiency virus (BIV). Northern blot analysis identified 11 of the 14 transcripts identified by RT-PCR, including a 7.8 kb gag/pol primary transcript and singly spliced transcripts. The complexity of the transcript map produced suggested that JDV replication is a highly regulated process. One of the aims of this thesis was to determine the functional role of the Tmx and Vif accessory proteins of the bovine lentiviruses. Although this aim was not achieved, molecular reagents were produced that will allow these investigations to proceed. The Vif and Tmx proteins of both JDV and BIV were successfully expressed as C-terminal fusions with glutathione S-transferase (GST) using the pGEX-6P-1 bacterial expression system. The recombinant proteins were purified and were recognised by both BIV and JDV antisera from Bos taurus and Bos javanicus respectively, and by antibody in sera from cattle that had been vaccinated with a tissue-derived JDV vaccine and also those that had been naturally infected with JDV. The Vif, Tmx and Rev proteins of JDV and vif BIV were successfully expressed in a Rev-independent manner in COS7 and bovine macrophage cells using a pcDNA3.1® mammalian expression system. Cellular localisation of the recombinant viral proteins varied in the 2 cell types: in COS7 cells, both JDV and BIV Vif were detected predominantly in the nucleus, whereas in bovine macrophage cells BIV Vif localised in the cytoplasm and JDV Vif localised in the cytoplasm and nuclear membrane. JDV Tmx localised in the cytoplasm of COS7 cells but the nuclear membrane of bovine macrophage cells, and BIV Tmx localised in the nucleus and nuclear membrane in both cell types and appeared to affect the morphology of the nucleus. Mutations of vif and tmx were also successfully engineered into an infectious clone of BIV and these mutated clones will provide a valuable resource for further investigation of the role of Vif and Tmx in replication of the bovine lentiviruses.
53

Psychic phenomena: Meditation perception, actuality - an Australian study

clogherau@yahoo.com.au, Emma Nattress January 2007 (has links)
This thesis presents the findings of an investigation into contemporary psychic phenomena as reported by Australian students. It asks the question: ¡¥do people experience psychic phenomena?¡¦ The study is an empirical one of reported psychic phenomena. It uses a questionnaire which involves the matching of perceptions of specific psychic phenomena, rather than an examination of psychic phenomena as such. The questionnaire is based on a medical diagnostic model. Its findings are benchmarked against a previous study and compared with other empirical studies. A comparison of the study's findings with those of more directly religious investigations undertaken overseas in countries with a longer monotheistic religious history than Australia: provides insight into the Australian attitude, generally recognised as being secular, towards psychic and or spiritual experiences; indicates that meditation is not necessarily a prerequisite for experience of psychic and or spiritual phenomena; and argues that commonalities between specific experiences, reported not only within the Australian secular survey but also as reported in the predominantly religious overseas studies, demonstrate that the scientific requirement of repeatability has been met, thus providing ground to believe in the actuality of the reported experiences.
54

Biochemical and structural analysis of the p58C and p68N domains of DNA polymerase alpha/primase

Weiner, Brian Edward. January 2008 (has links)
Thesis (Ph. D. in Biochemistry)--Vanderbilt University, Aug. 2008. / Title from title screen. Includes bibliographical references.
55

Thermodynamics and kinetics of DNA-protein interactions from single molecule force spectroscopy a dissertation /

Shokri, Leila. January 1900 (has links)
Thesis (Ph. D.)--Northeastern University, 2008. / Title from title page (viewed March 27, 2009). Graduate School of Arts and Sciences, Dept. of Physics. Includes bibliographical references (p. 130-157).
56

The pattern of initiation in the Chinese hamster DHFR origin of replication /

Wang, Shuntai. January 1998 (has links)
Thesis (Ph. D.)--University of Virginia, 1998. / Spine title: Study of DHFR DNA replication origin. Includes bibliographical references (p. 152-168). Also available online through Digital Dissertations.
57

Studies on the human homolog of the yeast Noc3p in human cells /

Zhong, Shan. January 2004 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 83-100). Also available in electronic version. Access restricted to campus users.
58

A study of DNA replication and repair proteins from Bacteriophage T4 and a related phage /

Senger, Anne. January 2004 (has links)
Thesis (M.S.)--University of Toledo, 2004. / Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Chemistry." Bibliography: leaves 111-112.
59

A new regulator of initiation of DNA replication : Noc3p /

Zhang, Yuexuan. January 2002 (has links)
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 74-80). Also available in electronic version. Access restricted to campus users.
60

Purification and properties of the replicative forms and replicative intermediates of pea enation mosaic virus

German, Thomas Lotell. January 1974 (has links)
Thesis (Ph. D.)--University of Wisconsin-Madison, 1974. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Page generated in 0.0337 seconds