Protein synthesis is a fundamental and ultimate process in living cells. Cells possess sophisticated machineries and continuously carry out complex processes. Monitoring protein synthesis in living cells not only inform us about the mechanism of translation but also deepen our insights about all aspects of life. Understanding the structure and mechanism of the ribosome and its associated factors helped us enlarge our knowledge on protein synthesis. Recently, with the dramatic advances of high-throughput sequencing and bioinformatics, a new technique called ribosome profiling emerged. By retrieving mRNA fragments protected by translating ribosomes, ribosome profiling reveals global ribosome occupancy along mRNAs in living cells, which can inform us with the identity and quantity of proteins being made. Easily adapted to other organisms, ribosome profiling technique is expanding its application in revealing various cellular activities as well as the knowledge on protein synthesis. Here, we report the mechanism of translating mRNA cleavage by endoribonuclease RelE in vivo. RelE is an endoribonuclease that is induced during nutrient deficiency stress and specifically cleaves translating mRNAs upon binding to the ribosomal A site. Overexpression of RelE in living cells causes growth arrest by inhibiting global translation. We monitored RelE activity in vivo upon overexpression using ribosome profiling. The data show that RelE actively cuts translating mRNAs whenever the ribosomal A site is accessible, resulting in truncated mRNAs. RelE causes the ribosome complexes to accumulate near the 5' end of genes as the process of ribosome rescue, translation, and cleavage by RelE repeats. RelE cleavage specific sub-codon level ribosome profiling data also represent reading frame in Escherichia coli and sequence specificity of RelE cleavage in vivo. We report another ribosome profiling study on a methyltransferase TrmD in E. coli. TrmD is known to methylate G37 (the residue at 3' side of anticodon) of some tRNAs and be responsible for codon-anticodon interaction. We constructed a TrmD depletion E. coli strain, whose deletion results in lethality of cells. Resulting depletion of m1G37 in the strain leads to growth arrest. Lack of m1G37 of some tRNAs whose codons start with C showed frequent frameshift when translating the gene message in vitro. By using ribosome profiling, we successfully observed significant difference on translation process when codons interact with anticodons of tRNAs lacking m1G37. The data reveal slow translation rate or pauses on the tRNAs when missing the appropriate methylation, which corresponds to the previous biochemical data in vitro.

[pt] Testes de relés de proteção têm assumido maior importância como resultado dos avanços tecnológicos. Novos relés podem ser projetados para atuarem rápido, sendo particularmente sensíveis a parte transitória da falta que eles supostamente detetam. Procedimentos usuais para testes de relés utilizam arquivos obtidos durante testes de falta, ou através de programas de simulação como o EMTP. Entretanto é muito difícil caracterizar um conjunto de formas de onda como suficiente para testes de relés. Como conseqüência, [16] sugeriu o uso de um procedimento do tipo Monte-Carlo para gerar ondas de modo a cobrir a maior parte das possíveis situações de transitório. Nesta metodologia, a linha de transmissão sob condição de falta é alimentada por um sistema equivalente fictício consistindo de um gerador de potência com uma impedância RLC. Quando a falta ocorre, o sistema oscila em determinadas freqüências. Estas freqüências são utilizadas para caracterizarem a forma de onda da falta. Neste trabalho um método de simulação de ondas viajantes é utilizado, baseado em filtros digitais, objetivando operação em tempo real. Como resultado, foi desenvolvido um procedimento de síntese do sistema fictício utilizando linhas de transmissão sem perdas ao invés de redes RLC. O software roda num computador tipo IBM PC tendo uma placa DSP baseada no chip TMS320C25. Os parâmetros da linha são calculados no PC e transferidos para a placa DSP, aonde a simulação é realizada em tempo real. Para casos com somente uma linha de transmissão, tal sistema trabalha com uma freqüência de amostragem de 4080 Hz representando transitórios de falta até 2040 Hz. Simulação OFF-LINE é também disponível para oferecer uma base de comparação entre a implementação em ponto fixo do DSP e a versão em ponto flutuante. Comparação com outro procedimento de simulação OFF-LINE é também apresentado com boa precisão entre os procedimentos ON-LINE e OFF-LINE. / [en] The testing of protective relays has become more and more important as result of technological advances. New relays may be designed to act fast, being particularly sensitive to the transient part of the fault supposed to be detected. A common procedure is either the use of real recorded faults during tests, or simulating these faults by computer programs, such as the EMP. However, it is difficult to characterize a unique set of transient waveforms sufficientfor the tests. As a consequence, it was suggested [16] the use of a Monte-Carlo type of procedure to generate waveforms in order to cover most of the possible transient situations. In this approach, the faulted transmission line is simulated, being fed by a fictitious equivalent system consisting of a power generator with an RLC load. When the fault occurs, there is resonance at particular chosen frequencies. These frequencies are used to characterize the fault waveform. In this work a travelling wave method of simulation is used, based on digital filters, looking for real time operation. As a result, it was developed a synthetic procedure for generating the fictitious system using lossless transmission lines instead of RLC networks. The software runs on a IBM PC type computer having a DSP board based on a TMS320C25. The transmission line parameters are evaluated in the PC and transferred to the DSP board, where real time the simulation is performed. For cases with only one lossless transmission line, the system works with a sampling frequency of 4.08 KHz, representing fault transients up to 20.04 KHz. Off-line simulation is available as well, primarily to offer a comparison basis between the fixed point DSP implementation and a floating point version. Comparison with other off-line simulation procedures are also presented with good agreemment between on-line and off-line procedures.

The purpose of this thesis is to gain knowledge about why young women in Sweden use Instagram, and how they feel when Instagram presents categories based on their interests and interactions. The thesis is based on previous research about the purpose of use, the behavior of algorithms, the adjustment of categories by relevance and the user experience. When combining previous research and the results gathered from several interviews with women between 18 - 30 years old who use Instagram, greater knowledge about the subject can be developed. The interviews gathered information about the interviewees' purpose of use and the user experience of Instagram's relevance adjusted categories. The results showed that women use Instagram to keep themselves updated about friends and family, get motivated in different sports activities and to compare themselves with other users. Although the content of the categories doesn’t always match the users’ desired content, the experience is generally positive. The possibilities with the function outweigh the concerned feelings that many of the users experienced with the categories.