Convergence results for projected line-search methods on varieties of low-rank matrices via \L{}ojasiewicz inequality

The aim of this paper is to derive convergence results for projected line-search methods on the real-algebraic variety $\mathcal{M}_{\le k}$ of real $m \times n$ matrices of rank at most $k$. Such methods extend Riemannian optimization methods, which are successfully used on the smooth manifold $\mathcal{M}_k$ of rank-$k$ matrices, to its closure by taking steps along gradient-related directions in the tangent cone, and afterwards projecting back to $\mathcal{M}_{\le k}$. Considering such a method circumvents the difficulties which arise from the nonclosedness and the unbounded curvature of $\mathcal{M}_k$. The pointwise convergence is obtained for real-analytic functions on the basis of a \L{}ojasiewicz inequality for the projection of the antigradient to the tangent cone. If the derived limit point lies on the smooth part of $\mathcal{M}_{\le k}$, i.e. in $\mathcal{M}_k$, this boils down to more or less known results, but with the benefit that asymptotic convergence rate estimates (for specific step-sizes) can be obtained without an a priori curvature bound, simply from the fact that the limit lies on a smooth manifold. At the same time, one can give a convincing justification for assuming critical points to lie in $\mathcal{M}_k$: if $X$ is a critical point of $f$ on $\mathcal{M}_{\le k}$, then either $X$ has rank $k$, or $\nabla f(X) = 0$

DNA segregation in mitochondria and beyond: insights from the trypanosomal tripartite attachment complex.

The tripartite attachment complex (TAC) of the single mitochondrion of trypanosomes allows precise segregation of its single nucleoid mitochondrial genome during cytokinesis. It couples the segregation of the duplicated mitochondrial genome to the segregation of the basal bodies of the flagella. Here, we provide a model of the molecular architecture of the TAC that explains how its eight essential subunits connect the basal body, across the mitochondrial membranes, with the mitochondrial genome. We also discuss how the TAC subunits are imported into the mitochondrion and how they assemble to form a new TAC. Finally, we present a comparative analysis of the trypanosomal TAC with open and closed mitotic spindles, which reveals conserved concepts between these diverse DNA segregation systems

Проектирование технологического процесса изготовления цилиндра и оснастки

РЕФЕРАТ Выпускная квалификационная работа 98 с., 12 рис., 27 табл., 7 источников, 6 прил. Ключевые слова: цилиндр, оснастка, литье, сверление, приспособление, технологический процесс. Объектом исследования является проектирование технологического процесса изготовления цилиндра Цель работы: проектирование технологического процесса изготовления цилиндра и оснастки В процессе исследования проводились анализ технологического процесса, технико-экономическая анализ, конструирование приспособления для сверления В результате выполнения работы был разработан технологический процесс изготовления детали цилиндр и сконструировано приспособление для сверления Основные конструктивные, технологические и технико-эксплуатационные характеристики: сконструированное приспособление для сверлABSTRACT Final qualifying work 98 p., 12 Fig., 27 tab., 7 springs, 6 ADJ. Key words: cylinder, tooling, casting, drilling, fitting, process. The object of study is (are) the Design of technological process of manufacturing of cylinder Goal – to Design the technological process of manufacturing of cylinder and snap In the process of investigation the analysis of the technological feasibility analysis, designing fixtures for drilling The result of the work was developed technological process of manufacturing parts and the cylinder fixture is designed for drilling The basic constructive, technological, technical-operational and features: the fixture is Designed for drilling consists of a casing, rod rack, cover, cylinder, prisms and the plate conductor. Level of implementation: the te

O USO DO MOODLE NA UFSC: DO APOIO AO ENSINO PRESENCIAL À GESTÃO UNIVERSITÁRIA

O objetivo desta pesquisa é investigar o potencial e o uso da ferramenta de ensino à distância Moodle, na forma de apoio ao ensino presencial, até a produção dos relatórios gerenciais e sua aplicação na administração universitária. A UFSC implantou um Moodle corporativo de apoio aos cursos presenciais, a partir da grande demanda do EaD, da disseminação cultural da ferramenta Moodle em nível mundial, bem como o do constante aprimoramento tecnológico desta plataforma, feito pelo grupo desenvolvedor. A criação de um grupo de suporte e a integração com o sistema acadêmico da UFSC foi disponibilizado, de forma efetiva, em 2009. A Superintendência de Governança Eletrônica e Tecnologia da Informação e Comunicação (SeTIC) disponibiliza suporte aos usuários e personaliza as funções de ajuda existentes no sistema. O Moodle integra-se os sistemas acadêmicos (CAGR/CAPG/CAPL) da UFSC o que facilita para os alunos e ao próprio setor de registro acadêmico, pois as informações são trocadas automaticamente entre os dois sistemas. Por exemplo, se todas as atividades de uma disciplina passarem pelo Moodle, no final do período acadêmico o Moodle faz a correção dos exercícios, calculando a nota final do aluno e permitindo o encaminhamento desta nota para o sistema acadêmico. Toda a comunidade acadêmica (alunos e professores) que utiliza o sistema acadêmico é cadastrada automaticamente no Moodle. Os investimentos em tecnologia da informação e comunicação (TIC) pela UFSC facilitaram o processo. Os principais resultados mostram a gradativa aceitação do padrão Moodle pela comunidade acadêmica, e mostram o pouco uso das informações gerenciais produzidas pelo sistema pelos administradores da UFSC

A ribosome-bound tRNA half stimulates mitochondrial translation during stress recovery in Trypanosoma brucei.

The protozoan parasite Trypanosoma brucei and its disease-causing relatives are among the few organisms that barely regulate the transcription of protein-coding genes. Yet, alterations in its gene expression are essential to survive in different host environments. Recently, tRNA-derived RNAs have been implicated as regulators of many cellular processes within and beyond translation. Previously, we identified the tRNAThr-3'-half (AGU) as a ribosome-associated non-coding RNA able to enhance global translation. Here we report that the tRNAThr-3'-half is generated upon starvation inside the mitochondria. The tRNAThr-3'-half associates with mitochondrial ribosomes and stimulates translation during stress recovery, positively affecting mitochondrial activity and, consequently, cellular energy production capacity. Our results describe an organelle ribosome-associated ncRNA involved in translation regulation to boost the central hub of energy metabolism as an immediate stress recovery response