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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.
31

Mutator phenotype of induced cryptic coliphage lambda prophage

Chu, Audrey 21 March 2005 (has links)
<p>These studies are based on the isolation of ë replication defective mutants that had acquired multiple point mutations within ë replication initiation genes O and P in a cryptic prophage (Hayes et al., 1998). Each mutant cell arose after shifting wild type cells with a cI[Ts] cryptic ë prophage deleted for int-kil, and from ren into E. coli, from 30oC to 42oC. Derepression of the trapped cryptic prophage kills the host cells (designated as RK+). Rare colony forming units survive and were designated as RK- mutants. This led to a hypothesis that ë replication-triggered cell stress provokes mutator activity, i.e., increases the frequency of replication errors within the simultaneously replicating chromosome of the host E. coli cells. We tested this hypothesis by asking three questions: (1) Do unselected, untargeted (with no link to ë fragment) auxotrophic mutations appear within the RK- mutant population selected from RK+ culture cells? (2) Is replication initiation from the cryptic ë fragment, or, alternatively, just expression of one or more ë genes required for the appearance of the unselected auxotrophic mutations? (3) Do E. coli functions participate in the appearance of unselected auxotrophic mutations within the RK- mutant population? Our results indicate that auxotrophic mutations unlinked to the ë fragment appeared at high frequency within RK- mutants. RK- auxotrophs arising on rich medium were identified by screening the survivor clones for growth on minimal medium. The appearance of RK- auxotrophic colonies at high frequency (>1 per 100 RK- mutants) leads us to conclude that auxotrophic mutations arise during the independent selection for RK- mutants. Conditions that inhibited ë fragment induction fully suppressed the mutator phenotype. Mutation of host dnaB such that the helicase does not support replication initiation from the induced ë fragment completely suppressed host cell killing, but not the appearance of auxotrophic mutations. We asked if E. coli error-prone polymerases IV and V, or gene functions regulated as part of the host SOS response contributed to the provoked mutator phenotype and observed no close correlation. We demonstrated that the RK+ starting cells did not have a distinct intrinsic mutator activity in several ways, including moving the cryptic ë fragment to different E. coli host cells, blocking ë fragment induction by the addition of a cI+ plasmid to eliminate ë gene expression at high temperatures, and independent assays for spontaneous rifampicin resistance. We found that the induced mutator phenotype associated with the appearance of untargeted auxotrophs was linked to the expression of lambda gene P, and did not require replication initiation from the cryptic ë prophage. We also found that the mutator phenotype of the induced cryptic ë fragment increased the frequency of rifampicin resistant colonies among the RK- mutant population. </p>
32

Conserved Charges Of Quadratic Curvature Gravity Theories In Arbitrary Backgrounds

Devecioglu, Deniz Olgu 01 September 2010 (has links) (PDF)
We generalize the definition of conserved gravitational Killing charges of quadratic curvature gravity theories to arbitrary backgrounds that admit at least one global (time-like) Killing vector. This charge definition is background gauge invariant and reduces correctly to the already known limit given by [1] when the background is a space of constant curvature. As an application we use this definition to compute the charges of various black holes in New Massive Gravity / namely the BTZ black hole, the black hole given in [2] and the Lifshitz black hole. Finally we compare the charges of these black holes with the ones given in [3], which uses a different approach.
33

Killing-yano Tensors

Nurbaki, Ali Nur 01 February 2011 (has links) (PDF)
By using the concept of isometry Killing vectors were introduced. Generalizing the Killing vectors Killing tensors of rank two were briefly introduced. Their metrical properties have been dealt.With this path Killing &ndash / Yano tensors were introduced as being some hidden space-time symmetries and also square roots of Killing tensors of rank two. Also physical importance of Killing &ndash / Yano tensors were briefly introduced. A calculation for 4D pp-wave metric is reviewed. Standart 5-D Kaluza- Klein theory is rewieved in an anholonomic base. 5- D Killing &ndash / Yano equations are written in this base. Simplified forms of these equations are given and the necessary conditions on the EM field tensor and the KY tensor are presented
34

Targeted Killing: Modern Solution or Modern Problem?

Sikkema, Paul 08 May 2014 (has links)
Modern warfare in general, and targeted killing (TK) in particular, challenge conventional legal paradigms. While some contend that targeted killing is a clear violation of law, others argue that it is the law that should adapt to its modern context. In this thesis, I argue in favor of the latter. I will first explain the two dominant paradigms through which one can interpret TK: law enforcement versus armed conflict, going on to argue that an armed conflict paradigm can be legitimately invoked. In sections IV and V, I examine the rights and status of targeted individuals in modern conflict. I will then explore Jeremy Waldron’s objection to TK—that its potential for abuse outweighs its utility. I conclude by arguing that TK, like all warfare, is justified only by the unacceptability of its alternative, and that the justification of all warfare abides under the same pragmatic presumption.
35

Aukos ir nusikaltėlio interakcija nužudymų ir neatsargių gyvybės atėmimų atvejais / Interaction between a Crime Victim and a Criminal in Cases of Murders and Negligent Killing

Valiūnienė, Orinta 24 February 2010 (has links)
Šiame darbe analizuojama tema „Nusikaltimo aukos ir nusikaltėlio interakcija nužudymų ir neatsargių gyvybės atėmimų atvejais“. Aptarta „interakcijos“ sąvoka, interakcijos rūšys, interakcijos tipai, taip pat nužudymo ir neatsargaus gyvybės atėmimo santykis. Mokslinės literatūros, oficialios statistikos ir baudžiamųjų bylų duomenų analizė atskleidė, jog viktiminėje situacijoje nusikaltimo auka, kaip ir nusikaltėlis, yra aktyvus, veikiantis dalyvis. Nužudymų ir neatsargių gyvybės atėmimų atvejais nusikaltimo subjektų interakcija labai panaši, t.y. lydima konflikto, todėl neatsargius gyvybės atėmimus dažnai sąlygoja tie patys veiksniai, kaip ir nužudymus. Nusikaltimo aukos ir nusikaltėlio interakcijos turinys beveik visuomet daro įtaką viktiminės situacijos formavimuisi ir (ar) jos baigčiai. Nužudymų ir neatsargių gyvybės atėmimų priežastys dažniausiai susijusios su nusikaltimo subjektų santykių pobūdžiu, kas vienaip ar kitaip formuoja konflikto sąlygas, patį konfliktą ir jo vyksmą. Didžiąją daugumą aukų ir nusikaltėlių siejo artimi šeiminiai ryšiai, gyvenimas kartu. Nusikaltimo subjektai dažnai konfliktavo ir vartojo psichologinį, fizinį smurtą vienas kito atžvilgiu. Atlikus baudžiamųjų bylų duomenų analizę, buvo pateiktos nusikaltimo subjektų santykių problemos, sąlygojančios nužudymus ar neatsargius gyvybės atėmimus, taip pat šių problemų pagrindu suformuluotos nusikaltimų gyvybei prevencijos galimybės. Darbo pabaigoje buvo padarytos išvados, patvirtinančios darbo įvade... [toliau žr. visą tekstą] / The topic of this paper is “Interaction between a Crime Victim and a Criminal in Cases of Murders and Negligent Killing”. Concept of “interaction”, kinds of interaction, types of interaction and relationship between murder and negligent killing is analyzed. Analysis of scholarly literature, official statistics and data analysis of criminal cases has revealed that in victim situation, a victim of a crime, as well as a criminal, is an active and acting participant. Interaction of crime subjects in cases of murder and negligent killing is very similar, i. e. followed by a conflict. Therefore, negligent killing is often determined by the same factors as murder. In most cases, the content of interaction between a crime victim and a criminal influences formation and (or) conclusion of victim situation. Reasons of murder and negligent killing are in most cases related to the nature of relationships between crime subjects. This, in one or another way, forms conditions for conflict, a conflict itself and its process. A large part of victims and criminals were related to each other by close family relations, living together. Subjects of crime often faced conflict situations, used psychological and physical violence against each other. After analyzing data of criminal cases, problems regarding the relationships of crime subjects are provided. These problems stipulate murders and negligent killings. Based on these problems, possibilities of avoiding such crimes are formulated. At the end... [to full text]
36

Evolution Of The Unnecessary : Investigating How fMet Became Central In Bacterial Translation Initiation

Catchpole, Ryan Joseph January 2015 (has links)
All bacteria initiate translation using formylated methionine, yet directly after translation, the formyl-group is removed. This sequence of addition and removal appears futile, yet every sequenced bacterial genome encodes the enzymes for formylation and deformylation, suggesting this process is essential. Puzzlingly, the process is absent from both Archaea and Eukaryotes, and moreover, bacterial mutants lacking both the formylase and deformylase activities are viable, albeit with a diminished growth rate. We created an Escherichia coli strain devoid of formylase and deformylase activity. This strain was then allowed to evolve over 1500 generations whereupon it reached wild-type growth rate, demonstrating that formylation can be completely dispensed with. This raises an additional question: if the formylation cycle is unnecessary, how did it emerge and why has it persisted? Our results show that the formylation-deformylation cycle could have evolved as a toxin-antitoxin pair (TA) with post-segregational killing (PSK) activity. TAs ‘addict’ cells to the plasmids that carry them by inducing PSK. We measured the stability of formylase-deformylase encoding plasmids and their ability to elicit PSK in our evolved E. coli strain. We report several lines of evidence consistent with the formylation-cycle having evolved from a plasmid-borne PSK element: 1) in the absence of deformylation, formyl-methionine on proteins is cytotoxic in bacteria 2) deformylation relieves the cytotoxicity of formyl-methionine, 3) the loss of a plasmid containing formylase and deformylase genes from evolved cells results in cessation of growth – a standard PSK phenotype. In addition, we introduced the E. coli formylase and deformylase genes into yeast and demonstrate that Met-tRNA formylation is not lethal, even in the absence of deformylation. This suggests PSK would be ineffectual in yeast, accounting for the absence of formylation from eukaryotic cytoplasmic translation. We also report the presence of formylase and deformylase genes in the two representative members of the archaeal Methanocopusculum genus. Moreover, we demonstrate that these genes have been acquired by a recent horizontal gene transfer from bacteria. Our results indicate that formylmethionine use in bacteria evolved, not through a direct functional benefit to cells, but through competition between infectious genetic elements.
37

A venda pessoal no segmento de tintas prediais : um estudo exploratorio nas tintas killing s/a e no principal canal de distribuicao de tintas

Pinto, Marcelo Machado Barbosa January 1996 (has links)
Este trabalho é o resultado de um estudo exploratório que descreve a maneira como é exercida a atividade de venda no principal canal de distribuição das tintas prediais. O exercício da atividade de venda é descrito pela forma como ele se processa e pela identificação dos atributos responsáveis pela geração, manutenção e modificação da atividade de venda. A obtenção destas informações se deu pela investigação da interação entre os agentes responsáveis pela comercialização das tintas prediais na Tintas Killing S/A e em algumas revendas de tinta e revendas de material de construção. A investigação prossegue pelo processo de análise e interpretação das informações, por meio de uma comparação entre os relatos obtidos com os agentes do canal de distribuição, ou seja, os vendedores industriais, os técnicos em produção e aplicação de tintas, os gerentes das revendas, os vendedores de varejo e os pintores. Desta forma foi possível identificar as atividades de cada agente do canal e o que cada um deles considera como determinante na sua atividade de venda, possibilitando-se agrupar atividades e atributos repetidos por diferentes agentes, esclarecendo-se assim corno e por que a venda é exercida no canal de distribuição de tintas prediais. / This paper results from an exploratory research that describes the practice of selling activity performed by a distribution channel of building paints. The practice of selling activity was depicted by the way it works and by the identification of some attributes that accounts for generation, support and changing of the selling activity. Data were collected from investigating the interaction among the distribution channel agents, represented by a manufacturer ( Killing paints ), and some resellers ( paint stores and building material stores ). The analysis and interpretation of information/data were obtained by comparing the speeches of several distribution channel agents, such as industrial sellers, technicians of paint production and application, managers of stores, retail sellers and painters. Thus, the activities of each type of agents of this distribution channel were identified separately and each agent expressed what had determined his/her selling activity. This account allowed to join both selling activities and attributes which had been repeated by different agents, clearing up how and why the selling activity was played by distribution channel of buildind paints.
38

A venda pessoal no segmento de tintas prediais : um estudo exploratorio nas tintas killing s/a e no principal canal de distribuicao de tintas

Pinto, Marcelo Machado Barbosa January 1996 (has links)
Este trabalho é o resultado de um estudo exploratório que descreve a maneira como é exercida a atividade de venda no principal canal de distribuição das tintas prediais. O exercício da atividade de venda é descrito pela forma como ele se processa e pela identificação dos atributos responsáveis pela geração, manutenção e modificação da atividade de venda. A obtenção destas informações se deu pela investigação da interação entre os agentes responsáveis pela comercialização das tintas prediais na Tintas Killing S/A e em algumas revendas de tinta e revendas de material de construção. A investigação prossegue pelo processo de análise e interpretação das informações, por meio de uma comparação entre os relatos obtidos com os agentes do canal de distribuição, ou seja, os vendedores industriais, os técnicos em produção e aplicação de tintas, os gerentes das revendas, os vendedores de varejo e os pintores. Desta forma foi possível identificar as atividades de cada agente do canal e o que cada um deles considera como determinante na sua atividade de venda, possibilitando-se agrupar atividades e atributos repetidos por diferentes agentes, esclarecendo-se assim corno e por que a venda é exercida no canal de distribuição de tintas prediais. / This paper results from an exploratory research that describes the practice of selling activity performed by a distribution channel of building paints. The practice of selling activity was depicted by the way it works and by the identification of some attributes that accounts for generation, support and changing of the selling activity. Data were collected from investigating the interaction among the distribution channel agents, represented by a manufacturer ( Killing paints ), and some resellers ( paint stores and building material stores ). The analysis and interpretation of information/data were obtained by comparing the speeches of several distribution channel agents, such as industrial sellers, technicians of paint production and application, managers of stores, retail sellers and painters. Thus, the activities of each type of agents of this distribution channel were identified separately and each agent expressed what had determined his/her selling activity. This account allowed to join both selling activities and attributes which had been repeated by different agents, clearing up how and why the selling activity was played by distribution channel of buildind paints.
39

Sobre hipersuperfÃcies com curvatura e bordo prescritos em variedades riemannianas / On hypersurfaces with prescribed curvature and boundary in riemannian manifolds

FlÃvio FranÃa Cruz 07 October 2011 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / We investigate the existence of hypersurfaces with prescribed curvature in a wide context. First we study the Dirichlet problem for a class of fully nonlinear elliptic equations of curvature type on a Riemannian manifold, which are closely related with the existence of hypersurfaces with prescribed curvature and boundary. In this setting we prove some existence results which extend to a Riemannian manifold previous results by Caffarelli, Nirenberg,Spruck and Bo Guan for the Euclidean space. We also study the existence of hypersurfaces with prescribed anisotropic mean curvature. We prove existence results for the Dirichlet problem related to the anisotropic mean curvature equation. This ensures the existence of Killing graphs with prescribed anisotropic mean curvature and boundary in a Riemannian manifold endowed with a nonsingular Killing vector field. Finally, we prove the existence of hyperspheres with prescribed anisotropic mean curvature in the Euclidean space, extending a previous result of Treibergs and Wei. / Neste trabalhamos investigamos a existÃncia de hipersuperfÃcies com curvatura prescrista num contexto amplo. Inicialmente estudamos o problema de Dirichlet para uma equaÃÃo totalmente nÃo-linear do tipo curvatura, definida em uma variedade Riemanniana. Este problema està intimamente relacionado a existÃncia de hipersuperfÃcies com curvatura e bordo prescritos. Neste contexto obtemos alguns resultados que estendem para uma variedade Riemanniana resultados obtidos anteriormente por Caffarelli, Nirenberg, Spruck e Bo Guan para o espaÃo Euclideano. Investigamos tambÃm a existÃncia de hipersuperfÃcies com curvatura mÃdia anisotrÃpica prescrita. Estabelecemos a solubilidade do problema de Dirichlet relacionado a equaÃÃo da curvatura mÃdia anisotrÃpica prescrita. Este resultado assegura a existncia de grÃficos de Killing com curvatura mÃdia anisotrÃpica e bordo prescritos numa variedade Riemanniana dotada com um campo de Killing sem singularidades. Finalmente, provamos a existÃncia de hiperesferas com curvatura mÃdia anisotrÃpica prescrita no espaÃo Euclideano, estendendo o resultado obtido Treibergs e Wei para a curvatura mÃdia usual.
40

A venda pessoal no segmento de tintas prediais : um estudo exploratorio nas tintas killing s/a e no principal canal de distribuicao de tintas

Pinto, Marcelo Machado Barbosa January 1996 (has links)
Este trabalho é o resultado de um estudo exploratório que descreve a maneira como é exercida a atividade de venda no principal canal de distribuição das tintas prediais. O exercício da atividade de venda é descrito pela forma como ele se processa e pela identificação dos atributos responsáveis pela geração, manutenção e modificação da atividade de venda. A obtenção destas informações se deu pela investigação da interação entre os agentes responsáveis pela comercialização das tintas prediais na Tintas Killing S/A e em algumas revendas de tinta e revendas de material de construção. A investigação prossegue pelo processo de análise e interpretação das informações, por meio de uma comparação entre os relatos obtidos com os agentes do canal de distribuição, ou seja, os vendedores industriais, os técnicos em produção e aplicação de tintas, os gerentes das revendas, os vendedores de varejo e os pintores. Desta forma foi possível identificar as atividades de cada agente do canal e o que cada um deles considera como determinante na sua atividade de venda, possibilitando-se agrupar atividades e atributos repetidos por diferentes agentes, esclarecendo-se assim corno e por que a venda é exercida no canal de distribuição de tintas prediais. / This paper results from an exploratory research that describes the practice of selling activity performed by a distribution channel of building paints. The practice of selling activity was depicted by the way it works and by the identification of some attributes that accounts for generation, support and changing of the selling activity. Data were collected from investigating the interaction among the distribution channel agents, represented by a manufacturer ( Killing paints ), and some resellers ( paint stores and building material stores ). The analysis and interpretation of information/data were obtained by comparing the speeches of several distribution channel agents, such as industrial sellers, technicians of paint production and application, managers of stores, retail sellers and painters. Thus, the activities of each type of agents of this distribution channel were identified separately and each agent expressed what had determined his/her selling activity. This account allowed to join both selling activities and attributes which had been repeated by different agents, clearing up how and why the selling activity was played by distribution channel of buildind paints.

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