Log in

Relevant bibliographies by topics / Recombination / Dissertations / Theses

Dissertations / Theses on the topic 'Recombination'

To see the other types of publications on this topic, follow the link: Recombination.

Author: Grafiati

Published: 4 June 2021

Last updated: 8 June 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Recombination.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Wong, Wan Yan. "Cosmological recombination." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5348.

Full text

Abstract:

In this thesis we focus on studying the physics of cosmological recombination and how the details of recombination affect the Cosmic Microwave Back ground (CMB) anisotropies. We present a detailed calculation of the spectral line distortions on the CMB spectrum arising from the Ly α and two-photon transitions in the recombination of hydrogen (H), as well as the corresponding lines from helium (He). The peak of these distortions mainly comes from the Ly α transition and occurs at about 170 μm, which is the Wien part of the CMB. The detection of this distortion would provide the most direct supporting evidence that the Universe was indeed once a plasma. The major theoretical limitation for extracting cosmological parameters from the CMB sky lies in the precision with which we can calculate the cosmologi cal recombination process. Uncertainty in the details of hydrogen and helium recombination could effectively increase the errors or bias the values of the cos mological parameters derived from microwave anisotropy experiments. With this motivation, we perform a multi-level calculation of the recombination of H and He with the addition of the spin-forbidden transition for neutral helium (He I), plus the higher order two-photon transitions for H and among singlet states of He I. Here, we relax the thermal equilibrium assumption among the higher excited states to investigate the effect of these extra forbidden transitions on the ionization fraction Xe and the CMB angular power spectrum C. We find that the inclusion of the spin-forbidden transition results in more than a percent change in Xe, while the higher order non-resonance two-photon transitions give much smaller effects compared with previous studies. Lastly we modify the cosmological recombination code RECFAST by introduc ing one more parameter to reproduce recent numerical results for the speed-up of helium recombination. Together with the existing hydrogen ‘fudge factor’, we vary these two parameters to account for the remaining dominant uncertainties in cosmological recombination. By using a Markov Chain Monte Carlo method with Planck forecast data, we find that we need to determine the parameters to better than 10% for HeT and 1% for H, in order to obtain negligible effects on the cosmological parameters.

APA, Harvard, Vancouver, ISO, and other styles

2

Naylor, G. A. "Recombination lasers." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355788.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Loveland, Damien Gerard. "Collisional recombination lasers." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305502.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Walters, K. "Genetic recombination processes." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269336.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Torres, J. T. "homologous genetic recombination." Thesis, London School of Hygiene and Tropical Medicine (University of London), 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431205.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Griffin, Craig David. "Genome recombination studies." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/30354.

Full text

Abstract:

In the Saccharomyces cerevisiae genome the regions adjacent to the 32 chromosome ends, the subtelomeres, are tethered at the nuclear periphery during vegetative / somatic growth and during sporulation / gametogenesis. This is in contrast to the rest of the genome, the interstitial regions, which are located throughout the nucleus. There is evidence that recombination between different subtelomeres is the exceptionally frequent, but that subtelomeres and interstitial regions do not recombine. These features of recombination involving subtelomeres may result from a structure that interacts with the subtelomeres, partitioning them from interstitial regions. Our aim was to characterise which part of the subtelomeres this recombination barrier interacts with. As a tool for estimating the rate and efficiency of recombination between different regions, a set of insertions into the S. cerevisiae genome was engineered. This set included 11 insertions at regular intervals along the terminal 10% of one chromosome arm, marking an interstitial region and the subtelomere. In addition, insertions were also made into a sample of other subtelomeres and interstitial regions. Both recombination during vegetative growth (mitotic recombination) and during sporulation (meiotic recombination) were assayed, between numerous combinations of these insertions. In agreement with previous studies, our results indicate that recombination between interstitial regions and subtelomeres is less efficient than recombination between different interstitial regions. Moreover, this is true of both mitotic and meiotic recombination. However, our efficiency data indicate this may result from tethering of subtelomeres at the nuclear periphery, rather than a partition in the nucleus. Tethering may suppress recombination between subtelomeres and most interstitial regions, simply by maintaining a large relative distance between these two regions. In contrast, the efficiency of mitotic and meiotic recombination between subtelomeres appear to be very different. Mitotic recombination between different subtelomeres appears to be exceptionally efficient, while meiotic recombination between different subtelomeres appears to be inefficient.

APA, Harvard, Vancouver, ISO, and other styles

7

Larson, Åsa. "Dynamics in dissociative recombination." Doctoral thesis, KTH, Physics, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3107.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Larson, Åsa. "Dynamics in dissociative recombination /." Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3107.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Mirza, Memona. "Genetic recombination in yeast." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357567.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Robertson, David L. "Recombination in primate lentiviruses." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336866.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Sevilla-Reyes, Edgar Enrique. "Recombination in human cytomegalovirus." Thesis, University of Glasgow, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433077.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Pinder, David. "Illegitimate recombination in plasmids." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/11260.

Full text

Abstract:

Illegitimate recombination mechanisms are important for genetic change within an organism. They are also the cause of many instability problems in biotechnology and have been associated with certain human genetic disorders and cancers. The original aim of this work was to construct a deletion (illegitimate recombination) resistant cosmid based, cloning system, for the cloning of unstable human DNA. Two 'mutant plasmids' pMS5 and pMS7 were isolated. The plasmids were derived from pUC18 and appeared to stabilise the propagation of a long DNA palindrome. The basic concept was to construct a new cosmid using pMS7 as part of the backbone. The construction of two new cosmids cDRII (Deletion Resistant) and cDRIII is described. However, they are unlikely to contain a mutation which stabilises unstable sequences. This thesis also describes the search for the 'mutation' in pMS7 by, single-strand conformation polymorphism and fragment swap analysis. This work led to the isolation of a novel mutation composed of both direct and inverted repeats, which I have called DIR. The presence of DIR in pAC2 (a derivative of pUC18, with the same DNA palindrome as pMS7), supports the absence of a stabilising 'mutation in pMS7. The structure of the DIR mutation is analysed in detail and a hypothesis for its formation is proposed. Finally, the behaviour of four long DNA palindromes (other than that cloned in pMS7), is investigated when ligated into pM^* (a derivative of pMS7).

APA, Harvard, Vancouver, ISO, and other styles

13

Hidalgo, Bravo Alberto. "Human telomeres and recombination." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/27809.

Full text

Abstract:

Telomeres are DNA-protein complexes that help protecting the end of linear chromosomes. They consist of repetitive DNA, in mammals the repeat unit is the hexanucleotide TTAGGG, these repeats span 5-20 kb. Under normal conditions in somatic cells, telomeres get shorter with every population doubling until they reach a critical length and then, the cell enters a checkpoint called senescence or M1 where it stops dividing. If the cell escapes senescence and continues dividing with further telomere shortening, it reaches a second checkpoint called crisis or M2. Crisis is characterized by telomere dysfunction leading to genomic instability that can end with cell death. However, some cells achieve to maintain telomere length by activating a telomere maintenance mechanism (TMM). The presence of a TMM is a hallmark of cancer cells. Two TMM have been described in human cells, one is the through the enzyme telomerase, which is active in 85% of cancers, and the second is a homologous recombination (HR) based mechanism called Alternative Lengthening of Telomeres (ALT) active in 15% of cancers. The evidence that the ALT pathway relies in HR was the observation that sequences can be copied from one telomere to another in ALT+ but not in telomerase+ cells and that several genes involved in HR are necessary for ALT progression. The ALT pathway is not the only event involving HR at telomeres. It has been shown that the human herpesvirus 6 (HHV-6) can integrate into human telomeres. Interestingly, HHV-6 possesses perfect telomeric repeats within its genome. The proposed mechanism for integration if through HR between the telomeric repeats present in the virus with the human telomere repeats. The aim of this work is to unravel the molecular mechanism underlying the ALT pathway and HHV-6 integration. The data obtained will contribute to the understanding of HR in human telomeres.

APA, Harvard, Vancouver, ISO, and other styles

14

Jia, Yu. "Heavy-quark recombination mechanism /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486462067841772.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Puttisong, Yuttapoom. "Spin-dependent Recombination in GaNAs." Thesis, Linköping University, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19355.

Full text

Abstract:

Spin filtering properties of novel GaNAs alloys are reported in this thesis. Spin-dependent recombination (SDR) in GaNAs via a deep paramagnetic defect center is intensively studied. By using the optical orientation photoluminescence (PL) technique, GaNAs is shown to be able to spin filter electrons injected from GaAs, which is a useful functional property for integratition with future electronic devices. The spin filtering ability is found to degrade in narrow GaNAs quantum well (QW) structures which is attributed to (i) acceleration of band-to-band recombination competing with the SDR process and to (ii) faster electron spin relaxation in the narrow QWs. Ga interstitial-related defect centers have been found to be responsible for the SDR process by using the optically detected magnetic resonance (ODMR) technique. The defects are found to be the dominant grown-in defects in GaNAs, commonly formed during both MBE and MOCVD growths. Methods to control the concentration of the Ga interstitials by varying doping, growth parameters and post-growth treatments are also examined.

APA, Harvard, Vancouver, ISO, and other styles

16

Guram, Prabhjot Kaur. "Modeling solar cells with recombination." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/39887.

Full text

Abstract:

An elementary model for the analysis of a photovoltaic solar cell is proposed. This analysis is rooted in the current-voltage device characteristics associated with a p-n junction in conjunction with a model for a solar flux controlled current source; this follows the approach of Prince [M. B. Prince, Journal of Applied Physics, vol. 26, pp. 553-540, 1955], the p-n junction architecture being that underlying the photovoltaic solar cell. Recombination processes were modeled through two means: (1) an empirical expression for the current-voltage device characteristics with an associated ideality factor, whose value determines the importance of recombination processes, and (2) a more advanced expression that includes a recombination current. It is shown that the simplified empirical expression is overly simplified and that its use leads to artifacts, i.e., the suggestion that recombination processes could actually enhance the fill-factor. In contrast, the more realistic current voltage device characteristic, which includes both ideal and recombination related current densities, suggests that recombination processes actually will reduce the fill-factor. This later observation is in accord with the experimental observation.

APA, Harvard, Vancouver, ISO, and other styles

17

Till, Ulrike. "Recombination kinetics of radical pairs." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267949.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Cardin, Niall. "Approximating the coalescent with recombination." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443603.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Kaiser, Vera B. "Molecular evolution under low recombination." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3946.

Full text

Abstract:

Analyzing regions in the genome with low levels of recombination helps understand the prevalence of sexual reproduction. Here, I show that variability in regions of reduced recombination in Drosophila can be explained by interference among strongly deleterious mutations; selection becomes progressively less effective in influencing the behaviour of neighbouring sites as the number of closely linked sites on a chromosome increases. I also show that the accumulation of loss-of-function mutations on the neo-Y chromosome of Drosophila miranda is compatible with a model of selection against such mutations alone, without the need to invoke the action of selective sweeps. I describe the discovery of two new sex-linked genes in the plant Silene latifolia, SlCyt and SlX9/SlY9. SlCyt has been recently translocated from an autosome to the X and shows signs of a selective sweep. Its possible role in having caused recombination arrest between the evolving X and Y chromosome is discussed. SlX9 still has an intact Y-linked copy that is presumably functional. Nucleotide diversity at SlY9 is very low, whereas SlX9 has an unusually high diversity and shows signs of introgression from S. dioica into S. latifolia, but the effect of this seems very localized.

APA, Harvard, Vancouver, ISO, and other styles

20

Gohari, Nasrollah Saleh. "Homologous recombination in mammalian cells." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414660.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Norbury, C. J. "Polyoma virus : polyadenylation and recombination." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/47448.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Sussman, Jason M. (Jason Michael). "Reducing recombination in organic photovoltaics." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69673.

Full text

Abstract:

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2011.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 55-65).
In this thesis, I consider two methods to improve organic photovoltaic efficiency: energy level cascades and promotion of triplet state excitons. The former relies on a thin layer of material placed between the active layers of a photovoltaic device to destabilize excitons. If the interfacial material is chosen properly, it can significantly improve device performance. The second method proposes to use quantum mechanical rules to reduce the rate of loss in organic photovoltaic devices. An electron in a triplet state cannot directly drop to the ground state by emitting a photon, so triplet excitons have longer lifetimes, and are thus more likely to diffuse to an interface to be dissociated. But this work suggests that, once they are at the interface, they are less likely to be dissociated than a singlet.
by Jason M. Sussman.
S.M.

APA, Harvard, Vancouver, ISO, and other styles

23

Blake, Catherine E. "Illegitimate recombination in Escherichia coli." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/15058.

Full text

Abstract:

The factors affecting deletion of long DNA palindromes from high copy number cloning vectors are investigated with particular reference to the mode of deletion and it is shown that the deletion of a 571 bp palindrome deleted from pMS7 using 3 bp repeats. A shorter 109 bp palindrome deleted from a related plasmid using 7 bp direct repeats and the mode of deletion is unaffected by the genotype of the host strain. There also appears to be a bias for the deletion of palindromic sequences on the lagging strand of a replication fork. It is also shown that in a wild-type E. coli strain there is inhibition of plasmid multimerization if the plasmids carry long palindromic sequences. It is proposed that the lack of plasmid multimers in this background is a result of the removal of palindromic sequences form the plasmids by the SbcCD protein of E. coli. In an sbcCD strain, plasmid DNA bearing long palindromes is not detected in a monomeric form, instead the DNA is present in multimeric forms, predominantly dimers. The ability to form plasmid multimers in this background may help to stabilise the palindromic sequences. The behaviour of palindromic sequences carried on plasmids is also investigated in recA sbcCD strains with a view to the correct choice of E. coli strain for the cloning of long palindromic sequences. Finally, the influence of an sbcCD mutation on the formation of araB-lacZ cistron fusion is investigated. The SbcCd proteins are thought to have a role in the processing of secondary structures formed by palindromic sequences. The formation of araB-lacZ fusions occurs via a strand transfer complex involving a complex genome rearrangement and secondary structure. Although an sbcCD mutation did not affect the kinetics or sequences specificity of fusion formation it is possible that SbcCD might have a role in processing the strand transfer complex which is not easily detected.

APA, Harvard, Vancouver, ISO, and other styles

24

Bastin, Robert. "Recombination processes in ionised plasmas." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445311/.

Full text

Abstract:

The observational analysis of astrophysical plasmas relies on accurate calculations of the atomic processes involved. The recombination spectra of singly ionised oxygen (O il) and carbon (C il) present excellent tools for investigating regions such as planetary nebulae and H II regions. In this thesis, detailed treatments of the recombination processes of both O II and C II are presented. Using the R-matrix solution to the close coupling equations, I present the results of accurate photoionisation calculations. Bound state energy levels are determined and oscillator strengths calculated for both species. Recombination coefficients were evalu ated for low n and 1, for C II in LS-coupling, and 0 II in intermediate coupling, taking particular care to treat resonances effectively. Sample photoionisation cross-sections are presented for both species, and compared to previous work. A complete radiative-cascade model is treated for both species, in order to determine line emissivities under nebular conditions at a wide range of temperatures and densities. Collisional effects are treated for C II, along with, for the first time, the effects of high temperature dielectronic recombination, allowing the modelling of regions of much higher electron temperature than previous work. The O II calculations were performed under intermediate coupling for the first time, allowing the effects of non-statistical popula tions of the parent ion fine-structure levels and dielectronic recombination onto bound states within this fine-structure to be taken into account in line emissivities. Detailed comparison with previous theoretical work was made for both species. The application of the C II and 0 n recombination spectra to determining tempera ture and densities from the observed spectra of a number of ionised nebulae is considered. The potential for using the new recombination spectra as diagnostic tools to solve some of the key problems in the study of ionised nebulae is demonstrated.

APA, Harvard, Vancouver, ISO, and other styles

25

Takehisa, Jun. "HIV Mixed Infections and Recombination." Kyoto University, 1999. http://hdl.handle.net/2433/181727.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Andersson, Jonas. "Ion recombination in liquid ionization chambers : development of an experimental method to quantify general recombination." Doctoral thesis, Umeå universitet, Radiofysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-68942.

Full text

Abstract:

An experimental method (the two-dose-rate method) for the correction of general recombination losses in liquid ionization chambers has been developed and employed in experiments with different liquids and radiation qualities. The method is based on a disassociation of initial and general recombination, since an ionized liquid is simultaneously affected by both of these processes. The two-dose-rate method has been compared to an existing method for general recombination correction for liquid ionization chambers, and has been found to be the most robust method presently available. The soundness of modelling general recombination in liquids on existing theory for gases has been evaluated, and experiments indicate that the process of general recombination is similar in a gas and a liquid. It is thus reasonable to employ theory for gases in the two-dose-rate method to achieve experimental corrections for general recombination in liquids. There are uncertainties in the disassociation of initial and general recombination in the two-dose-rate method for low applied voltages, where initial recombination has been found to cause deviating results for different liquids and radiation qualities. Sensitivity to ambient electric fields has been identified in the microLion liquid ionization chamber (PTW, Germany). Experimental data may thus be perturbed if measurements are conducted in the presence of ambient electric fields, and the sensitivity has been found to increase with an increase in the applied voltage. This can prove to be experimentally limiting since general recombination may be too severe for accurate corrections if the applied voltage is low.

APA, Harvard, Vancouver, ISO, and other styles

27

Hinch, Anjali Gupta. "The landscape of recombination in African Americans : leveraging human population variation to investigate homologous recombination." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:585e2ad8-b6e7-458b-b547-fb955d17c561.

Full text

Abstract:

Homologous recombination is a highly regulated and complex biological process required for sexual reproduction in humans and many other species. The mechanisms of initiation and control of this process, however, are only partially understood. The aim of this work is to tease apart and utilize the differences in recombination localization between human populations to understand the underlying biological processes.

APA, Harvard, Vancouver, ISO, and other styles

28

Hamberg, Mathias. "Dissociative Recombination of Astrochemically Interesting Ions." Doctoral thesis, Stockholm : Department of Physics, Stockholm University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38833.

Full text

Abstract:

Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: In press. Paper 3: Manuscript. Paper 5: Manuscript.

APA, Harvard, Vancouver, ISO, and other styles

29

Savolainen, Linda. "Transcription Associated Recombination in Mammalian Cells." Doctoral thesis, Stockholm : Department of Genetics, Microbiology and Toxicology, Stockholm University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38931.

Full text

Abstract:

Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

APA, Harvard, Vancouver, ISO, and other styles

30

Coburn, Brian John. "Multi-Species Influenza Models with Recombination." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/363.

Full text

Abstract:

Avian influenza strains have been proven to be highly virulent in human populations, killing approximately 70 percent of infected individuals. Although the virus is able to spread across species from birds-to-humans, some strains, such as H5N1, have not been observed to spread from human-to-human. Pigs are capable of infection by both avian and human strains and seem to be likely candidates as intermediate hosts for co-infection of the inter-species strains. A co-infected pig potentially acts as a mixing vessel and could produce a new strain as a result of a recombination process. Humans could be immunologically naive to these new strains, hence making them super-strains. We propose an interacting host system (IHS) for such a process that considers three host species that interact by sharing strains; that is, a primary and secondary host species can both infect an intermediate host. When an intermediate host is co-infected with the strains from both the other hosts, co-infected individuals may become carriers of a super-strain back into the primary host population. The model is formulated as a classical susceptible-infectious-susceptible (SIS) model, where the primary and intermediate host species have a super-infection and co-infection with recombination structure, respectively. The intermediate host is coupled to the other host species at compartments of given infectious subclasses of the primary and secondary hosts. We use the model to give a new perspective for the trade-off hypothesis for disease virulence, by analyzing the behavior of a highly virulent super-strain. We give permanence conditions for a number of the subsystems of the IHS in terms of basic reproductive numbers of independent strains. We also simulate several relevant scenarios showing complicated dynamics and connections with epidemic forecasting.

APA, Harvard, Vancouver, ISO, and other styles

31

Kavanagh, Anthony. "Dielectronic recombination in highly charged ions." Thesis, Queen's University Belfast, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486225.

Full text

Abstract:

Dielectronicrecombination resonance strengths for the KLL and KLM manifolds were measured for various ions. The He-like, Li-Iike and Be-like charge states of Iron, Yttrium and Holmium were measured. As were the He-like to C-Iike ions of Iodine and Bismuth. The ion charge states were created and maintained in the Tokyo electron beam ion trap. The charge balance was inferred from axially escaping ions. The electron beam energy was slowly scanned across dielectronic recombination manifolds ensuring charge state equilibrium was maintained. The ratio of adjacent ion charge states was then plotted against the beam energy. The ratio was first corrected for variations in charge exchange and escape rates and then a non-resonant background was removed leaving only the resonant contribution. By normalizing the resultant ratio to theoretical electron impact ionization cross sections and integrating the line shape, the resonance strengths were obtained. The obtained resonance strengths agree well with theoretical calculations and allowed the generation of Z scaling laws for He-like, Li-Iike and Be-like ions in the KLL and KLM manifolds. A simple isonuclear scaling was also generated for KLL and KLM although further testing is required for confidence in this last scaling law.

APA, Harvard, Vancouver, ISO, and other styles

32

Sze, Pui King Ivy. "Conservation laws in recombination kinetic theory." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26089.

Full text

Abstract:

The hydrodynamic equations of change for a reacting gas mixture of monomers and dimers are studied. The gas is considered to be dilute and described by the kinetic theory of Lowry and Snider (J. Chem. Phys. 61, 2320 (1974)). From the kinetic equations for the density operators representing the monomer and dimer, the equations of change for one-molecule observables are obtained. Since the energy operator involves the intermolecular potential energy, it is necessary to derive the energy balance equation from the von Neumann equation, since this includes molecule-molecule correlations. As well, the kinetic theory formulated by Lowry and Snider is rewritten so that rearrangement collisions are emphasized. A collisional sum rule is derived involving the commutation properties of channel projectors and their respective potentials. A known property of the optical theorem is that it identifies the reactive loss terms as part of the non-reactive transition superoperators. The sum rule is applied to rewrite the non-reactive transition superoperators so as to display the reactive loss terms. This aids in establishing conservation laws for the physical observables of mass, linear momentum, angular momentum and energy. A form of the optical theorem in which kinetic energy off-diagonality is allowed for is also derived. Both the optical theorem and the sum rule are based on the strong orthogonality hypothesis, which plays a fundamental role in the Lowry-Snider theory. On localising the physical attributes at the centres of mass of the molecules, the contributions to the equations of change from collisional transfer (due to the forces and torques between the collision partners) and from the transfer of the physical attributes from the reactants to the products are identified. The transformation of dimer internal degrees of freedom into monomer translational degrees of freedom or vice versa when a dimer Is dissociated or formed is found to contribute to the equations of change by virtue of the differing locality of the collision partners. The decomposition of the kinetic energy operator into its components for radial and rotational motions allows the kinetic energy flux contributions associated with the pressure tensor and the molecular angular momentum flux to be identified.
Science, Faculty of
Chemistry, Department of
Graduate

APA, Harvard, Vancouver, ISO, and other styles

33

Brinne, Roos Johanna. "Electron Recombination with Small Molecular Ions." Licentiate thesis, Stockholm : Bioteknologi, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4375.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Webb, Alexandra. "Detecting recombination using hidden markov models." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510259.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Ciccoricco, Dave. "Repetition and recombination: Reading network fiction." Thesis, University of Canterbury. English, 2005. http://hdl.handle.net/10092/4770.

Full text

Abstract:

Repetition and Recombination: Reading Network Fiction is the first full-length study devoted to network fiction. Network fictions are narrative texts in digitallynetworked environments that make use of hypertext technology in order to create emergent and recombinatory narratives (unlike interactive, or "arborescent," fictions that employ mutually exclusive plotlines). They represent a coalescence of works that predate and postdate the World Wide Web but share an aesthetic drive that exploits the networking potential of digital composition and foregrounds a distinctive quality of narrative recurrence and return. The thesis consists of (1) a critical and theoretical component that returns to printbased narratology in light of digital literature; (2) analyses of network fictions from the first-wave of digital literature published as stand-alone software applications; and (3) analyses of second-wave network fictions published on the World Wide Web. The analyses each focus on the interplay of the material, formal, and semantic elements of network narrative, an jnterplay that is framed by the dynamics of repetition. Furthermore, the thesis illustrates how concepts of orientation, immersion, constraint, and mobility, which have long informed the experience of reading narrative fiction, take on new meaning in digital environments. The primary contribution of the thesis is to an aesthetic and narratological understanding of this nascent form of digital literature. However, cybertext theory, systems theory, postfeminist theory, and post-structuralist and deconstructionist theory (when dissociated from early hypertext theory that claimed to literalize, embody, or fulfill it) all inform its critical understanding. The movement in the arts away from representation and toward simulation, away from the dynamics of reading and interpretation and toward the dynamics of interaction and play has led to exaggerated or alarmist claims for the endangerment of the literary arts. At the same time, some have simply doubted that the conceptual and discursive intricacy of print fiction can migrate to the screen, where performativity and immediacy are privileged. Against these claims, the thesis attests to the verbal complexity and conceptual depth of a body of writing created for the surface of the screen.

APA, Harvard, Vancouver, ISO, and other styles

36

Davey, Alisdair Richard. "The recombination spectrum of carbon II." Thesis, University College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288641.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Mukund, Shreyas Ram. "Single molecule biophysics of homologous recombination." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708842.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Nkambule, Sifiso Musa. "Theoretical studies of charge recombination reactions." Licentiate thesis, Stockholms universitet, Fysikum, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-113405.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Masse, Nicholas. "Recombination processes in quantum dot lasers." Thesis, University of Surrey, 2008. http://epubs.surrey.ac.uk/844607/.

Full text

Abstract:

The drive for low threshold and temperature-stable semiconductor lasers for telecommunication applications has led to a significant interest in quantum dot (QD) lasers emitting in the 1.3 mum and 1.5 mum wavelength range. The literature shows that although low threshold current densities can be achieved, this is usually at the expense of a poor temperature stability. Low-temperature and high-pressure measurements of the threshold current and its radiative component are performed on undoped and p-doped 1.3 mum InAs/GaAs and 1.5 mum InAs/InP (311)B QD lasers. The results show that despite a fairly temperature-stable radiative current around room temperature, undoped QD lasers suffer from a poor temperature stability of their threshold current. This is because there is a large contribution (70% and 90% of the threshold current at room temperature in 1.3 and 1.5 mum lasers, respectively) from a strongly temperature sensitive non-radiative Auger recombination process. Several pieces of evidence are found to explain the observed decrease of the radiative current, explained by an improvement of the carrier distribution with increasing temperature. We find that in p-doped devices the temperature dependence of the radiative component of the threshold current can be modified by the doping. In these devices the radiative current can decrease with increasing temperature around room temperature while the non-radiative current increases. This results in a small range of temperatures over which the threshold current is constant (from ~ 270 to 300 K). This effect is very sensitive to the doping concentration. If the doping concentration is carefully chosen, this can result in high T0 devices but with larger threshold currents than in comparable undoped lasers. Gain measurements reveal that the differential gain of p-doped lasers is less than that of the undoped devices because of the increased non-radiative current and the non-thermal distribution of the carriers induced by the doping. Finally, a new method is demonstrated to measure the band gap dependence of the Auger coefficient, C, using a combination of high hydrostatic pressure measurements coupled with gain calculations.

APA, Harvard, Vancouver, ISO, and other styles

40

Morawiec, Anna Franciszczak. "Studies of mitochondrial recombination in yeast /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487681148542795.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Groden, Joanna Louise. "Somatic recombination in Bloom's syndrome cells /." Access full-text from WCMC, 1989. http://proquest.umi.com/pqdweb?did=744576191&sid=1&Fmt=2&clientId=8424&RQT=309&VName=PQD.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Houston, Peter Louis. "Biochemical characterization of genetic recombination proteins /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Li, Bo. "Inelastic collision and three-body recombination." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29779.

Full text

Abstract:

Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2009.
Committee Chair: M. Raymond Flannery; Committee Member: Daniel Goldman; Committee Member: Dewey H. Hodges; Committee Member: Li You; Committee Member: Turgay Uzer. Part of the SMARTech Electronic Thesis and Dissertation Collection.

APA, Harvard, Vancouver, ISO, and other styles

44

von, Wangenheim Ute [Verfasser]. "Single-crossover recombination and ancestral recombination trees / Ute von Wangenheim. Technische Fakultät - AG Biomathematik und Theoretische Bioinformatik." Bielefeld : Universitätsbibliothek Bielefeld, Hochschulschriften, 2011. http://d-nb.info/1017477302/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Kasakow, Carmen Vanessa [Verfasser], and Frank [Akademischer Betreuer] Kirchhoff. "Astrocyte-specific gene recombination in vivo : Tamoxifen-induced and -independent recombination / Carmen Vanessa Kasakow ; Betreuer: Frank Kirchhoff." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2018. http://d-nb.info/1200408535/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Fernandes, Joiselle Blanche. "Identification et caractérisation fonctionnelle de gènes contrôlant la fréquence de crossovers méiotiques." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS303/document.

Full text

Abstract:

Les crossing-overs (CO) sont issus d’échange réciproque de matériel génétique entre les chromosomes homologues. Les COs produisent de la diversité génétique et sont essentiels chez la plupart des eucaryotes, pour la distribution équilibrée des chromosomes lors de la méiose. Malgré leur importance, et un large excès de précurseurs moléculaires, le nombre de CO est très limité dans la grande majorité des espèces (Typiquement 1 à 4 par paire de chromosomes). Cela suggère que les COs sont étroitement régulés, mais les mécanismes sous-jacents sont mal connus. Pour identifier les gènes qui limitent la formation des CO, l’équipe a mené un crible génétique chez Arabidopsis thaliana. Ces travaux ont mené à l’identification de plusieurs facteurs anti-CO, définissant trois voies : (i) L’hélicase FANCM et ses co-facteurs ; (ii) L’AAA-ATPase FIDGETIN-LIKE-1 (FIGL1) ; (iii) Le complexe RECQ4-Topoisomerase 3α-RMI1.Le premier objectif de ma thèse est d’explorer les relations entre ces trois voies en s’attachant aux questions suivantes ; (1) Jusqu’où peut-on augmenter la recombinaison en combinant les mutations dans FANCM, FIGL1 et RECQ4 ? Nous avons montré que la plus forte augmentation de recombinaison était obtenue dans recq4 figl1, atteignant 7,5 fois la fréquence du sauvage en moyenne sur le génome. (2) Quel est la distribution de ces extra-COs ? L’augmentation de recombinaison n’est pas homogène le long du génome : Les fréquences de CO augmente fortement des centromères vers les télomères, avec les plus hautes fréquences observées dans les régions distales. (3) La modification des fréquences de recombinaison est-elle identique lors des méioses mâles et femelle ? Chez le sauvage, la fréquence de recombinaison est plus élevée lors de la méiose mâle que femelle. Au contraire, la recombinaison femelle devient plus élevée que la recombinaison mâle chez les mutants recq4 et recq4 figl1. Ceci suggère que des contraintes qui s’appliquent sur la formation des CO lors de la méiose femelle sont relâchées chez ces mutants. En poursuivant le crible génétique, un nouveau mutant hyper-recombinant a été identifié. Le second objectif de ma thèse fut d’identifier et de caractériser fonctionnellement le gène correspondant. Une cartographie génétique et des études d’interactions protéine-protéine, ont mené à l’identification d’un facteur qui interagit directement avec FIGL1 et semble former un complexe conservé depuis les plantes jusqu’au mammifères. Nous avons baptisé cette protéine FLIP (Fidgetin-like-1 interacting protein). Les fréquences de recombinaisons sont augmentées dans flip-1, confirmant que FLIP1 limite la formation des COs. Des études d’épistasie ont montré que FLIP et FIGL1 agissent dans la même voie. De plus les protéines FIGL1/FLIP d’Arabidopsis ou humaine, interagissent avec RAD51 et DMC1, les deux protéines qui catalyse une étape clef de la recombinaison, l’invasion d’un ADN homologue. Finalement, dans flip comme dans figl1, la dynamique de DMC1 est modifiée. Nous proposons donc un modèle dans lequel le complexe FLIP-FIGL1 régule négativement l’activité de RAD51/DMC1 pour limiter la formation des COs. L’étude du complexe conservé FLIP-FIGL1 a mis en évidence un nouveau mode de régulation de la recombinaison, qui agit vraisemblablement à l’étape clé de l’échange de brin homologue. De plus, l’augmentation des CO sans précédent obtenues chez recq4 figl1 peut être d’un grand intérêt pour l’amélioration des plantes en permettant de diversité de nouvelles combinaisons alléliques
Meiotic crossovers (CO) are formed by reciprocal exchange of genetic material between the homologous chromosomes. CO generate genetic diversity and are essential for the proper segregation of chromosomes during meiosis in most eukaryotes. Despite their significance and a large excess of CO precursors, CO number is very low in vast majority of species (typically one to three per chromosome pair). This indicates that COs are tightly regulated but the underlying mechanisms of this limit remain elusive. In order to identify genes that limit COs, a genetic screen was performed in Arabidopsis thaliana. This led to the identification and characterization of several anti-CO factors belonging to three different pathways: (i) The FANCM helicase and its cofactors (ii) The AAA-ATPase FIDGETIN-LIKE-1 (FIGL1) (iii) The RECQ4 -Topoisomerase 3α-RMI1 complex. The first objective was to understand the functional relationship between these three pathways and to address following questions: (1) how far can we increase recombination when combining mutations in FANCM, FIGL1 and RECQ4? We show that the highest increase in recombination was obtained in figl1 recq4, reaching to 7.5 fold the wild type level, on average genome wide. (2) How is the distribution of recombination events genome wide in mutants? The increased CO frequency in the mutants was not uniform throughout the genome. CO frequency rises from the centromere to telomeres, with distal intervals having highest COs (3) is the recombination frequency increase same in both male and female? In Arabidopsis wild type, male has higher recombination than female meiosis. In contrast, in recq4 and recq4 figl1, female recombination was higher than male. This suggests that certain constraints that apply to CO formation in wild type females are relieved in the mutant. By continuing the same genetic screen, a novel anti-CO mutant was identified. The second objective was to identify and functionally characterize the corresponding gene. Genetic mapping and protein interaction studies led to the identification of a factor that directly interacts with FIGL1 and appears to form a conserved complex both in Arabidopsis and humans. Hence, the factor was named FLIP (Fidgetin-like-1 interacting protein). Recombination frequency is increased in flip, confirming that FLIP limit COs. Epistasis studies showed that FLIP and FIGL1 act in same pathway. Further, FIGL1/FLIP proteins of Arabidopsis and humans directly interact with the recombinases RAD51 and DMC1 which catalyze a crucial step of homologous recombination, the inter homolog strand invasion. In addition flip like figl1 modifies dynamics of DMC1. We thus propose a model wherein the FLIP-FIGL1 complex negatively regulates RAD51/DMC1 to limit CO formation. Studying the conserved FIGL1-FLIP complex led to the identification of a novel mode of regulation of recombination, that likely acts at the key step of homologous strand invasion. Further the unprecedented level of CO increase in recq4figl1 in hybrids could be of great interest for crop improvement, allowing the production of novel allele combinations

APA, Harvard, Vancouver, ISO, and other styles

47

Böhme, Christoph. "Dynamics of spin-dependent charge carrier recombination." [S.l.] : [s.n.], 2003. http://archiv.ub.uni-marburg.de/diss/z2003/0183.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Schiavo, Ebe. "Molecular mechanisms controlling immunoglobulin class switch recombination." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAJ084/document.

Full text

Abstract:

Lors des réponses immunitaires, le répertoire des lymphocytes B est diversifié par l’hypermutation somatique (HMS) et la commutation isotypique (CI), dépendant d’«activation-induced cytidine deaminase» (AID), qui introduit des lésions dans les gènes Ig. Une déficience d’AID cause un défaut d’HMS et de CI; par contre, une délétion du domaine C-terminal d’AID cause un défaut spécifique de la CI, suggérant que ce domaine interagit avec des facteurs spécifiques de la CI. Pour identifier ces facteurs, nous avons étudié une immunodéficience présentant un défaut de la CI non lié à la carence d’AID ni à un défaut d’HMS. De plus, les cassures de l’ADN ne sont pas détectées au niveau des gènes Ig suggérant qu’AID n’est pas correctement ciblée dans ces loci. Nous avons identifié et analysé des candidats : Spt6, les cohésines et le complexe Smc5/6. Dans les cellules B activées, AID interagit avec Spt6, Spt5, l’ARN polymérase II et le complexe PAF. Par contre, les cohésines pourraient réguler la structure du locus IgH lors de la CI et la voie de réparation des cassures de l’ADN générées pendant la CI. Ces résultats contribuent à une meilleure compréhension des étapes de la CI
During immune responses, B cell repertoire is diversified through somatic hypermutation (SHM) and class switch recombination (CSR). SHM and CSR require activation-induced cytidine deaminase (AID), which induces DNA damage. While AID deficiency abrogates SHM and CSR, C-terminal truncations impair CSR without affecting SHM and it has been proposed that AID C-terminal domain associates with CSR-specific factor(s). In order to identify these factors, we studied a human CSR-specific immunodeficiency, characterized by normal SHM and AID expression. B cells from these patients do not display DSBs at switch (S) regions, suggesting that they might lack an AID-binding factor(s) required to target AID to S regions during CSR. Through a multi- approach strategy, we identified and analyzed candidate factors, including Spt6, the cohesin complex and the Smc5/6 complex. We show that, in B cells poised to undergo CSR, AID is in a complex with Spt6, Spt5, the RNA polymerase II and the PAF complex while cohesins might regulate the 3D structure of the IgH locus and the pathway of DSBs repair at the Ig S regions. Our work thus contributes to a better understanding of the CSR reaction

APA, Harvard, Vancouver, ISO, and other styles

49

Xing, Xu. "Structural studies of homologous recombination in bacteria." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1186680748.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Radford, Sarah J. Sekelsky Jeff. "Heteroduplex DNA and meiotic recombination in Drosophila." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,711.

Full text

Abstract:

Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.
Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Curriculum in Genetics and Molecular Biology." Discipline: Genetics and Molecular Biology; Department/School: Medicine.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!