Time-Resolved Quantification of Centrosomes by Automated Image Analysis Suggests Limiting Component to Set Centrosome Size in C. Elegans Embryos

The centrosome is a dynamic organelle found in all animal cells that serves as a microtubule organizing center during cell division. Most of the centrosome components have been identified by genetic screens over the last decade, but little is known about how these components interact with each other to form a functional centrosome. Towards a better understanding of the molecular organization of the centrosome, we investigated the mechanism that regulates the size of the centrosome in the early C. elegans embryo. For this, we monitored fluorescently labeled centrosomes in living embryos and developed a suite of image analysis algorithms to quantify the centrosomes in the resulting 3D time-lapse images. In particular, we developed a novel algorithm involving a two-stage linking process for tracking entrosomes, which is a multi-object tracking task. This fully automated analysis pipeline enabled us to acquire time-resolved data of centrosome growth in a large number of embryos and could detect subtle phenotypes that were missed by previous assays based on manual image analysis. In a first set of experiments, we quantified centrosome size over development in wild-type embryos and made three essential observations. First, centrosome volume scales proportionately with cell volume. Second, beginning at the 4-cell stage, when cells are small, centrosome size plateaus during the cell cycle. Third, the total centrosome volume the embryo gives rise to in any one cell stage is approximately constant. Based on our observations, we propose a ‘limiting component’ model in which centrosome size is limited by the amounts of maternally derived centrosome components. In a second set of experiments, we tested our hypothesis by varying cell size, centrosome number and microtubule-mediated pulling forces. We then manipulated the amounts of several centrosomal proteins and found that the conserved centriolar and pericentriolar material protein SPD-2 is one such component that determines centrosome size

Understanding African agency in peace and security: Tanzania's implementation of "non-indifference" in Somalia

Against the backdrop of the plurality of agents and contexts, Africa's peace and security norms have remained contested and open to interpretation in political practice. This article argues that African agents manifest their agencies precisely through their distinct interpretation and implementation of security norms. Based on Tanzania's rejection to join the African Union Mission in Somalia (AMISOM) in 2007, this article zooms into the underlying domestic complexities by focusing in particular on the crucial influence of national identities for the ongoing construction of normative meaning in Africa's peace and security landscape.Aufgrund der immensen Pluralität von Erfahrungen und Interessen Afrikanischer Akteure bleiben Afrikas sicherheitspolitische Normen in ihrer Interpretation und Implementierung stets ambivalent und vielseitig deutbar. Dieser Artikel argumentiert, dass sich Afrikanische Agency genau in der Interpretation normativer Bedeutungen manifestiert. Anhand Tansanias Entscheidung sich nicht militärisch im Rahmen der Mission der Afrikanischen Union in Somalia (AMISOM) zu beteiligen, analysiert dieser Artikel die zugrunde liegende innenpolitischen und normativen Komplexitäten, welche die Konstruktion Afrikanischer Agency im Bereich Sicherheit und Frieden bestimmen

What can the lit lab do for you? a qualitative analysis of high school literacy lab participants

The purpose of the study is to document the changes in student progress, motivation, and achievement. The specific aim is to see what happens when students replace a traditional study hall with small group guided instruction in a literacy lab. Motivation profiles, goal setting, and reflection are all analyzed. The focus group of students demonstrated changes in how they viewed themselves as learners and in their academic endeavor to achieve goals. The implications for teaching in a literacy lab environment are discussed

Digital, multimodal composition in English for architects and civil engineers programs: Implications for theory and practice in educational semiotics

The applied disciplines of architecture and civil engineering (A&CE) require students to communicate multimodally and to manipulate meaning across media and modes. In their disciplinary studies for example, students must be able to transform the language of lectures and textbooks into diagrams; in their future workplaces, to transform reports into floor plans and 3D models. Such multimodal literacy, however, is not typically reflected in their related subject-specific English language courses, which are aimed at civil engineering and architecture track students for whom English is a second or additional language (L2). Rather than incorporating multimodal literacy skills, these courses tend to focus on the acquisition of discipline-specific written and spoken language. As such, to better reflect their academic and professional practice, students in two university courses of English for A&CE were tasked with creating digital, multimodal artefacts to explain a concept from either of these fields to a lay audience. These artefacts, and subsequent interviews with the students as both composers and audience members, were examined through lenses drawn from the fields of social semiotics and multimodality. Three main results have emerged, firstly, that multimodal assessment tasks such as these promote the communication of technical concepts, encourage opportunities for language development and also develop the students as social agents. Secondly, that A&CE models occurred frequently in the dataset, suggesting that models make meaning within a system of signs and have specific affordances which are observable when students ‘transduce’ between modes. Lastly, that interpersonal meaning was surprisingly important to the students, with 78% of artefacts featuring some kind of ‘mediated focalisation’, a framing technique more common to narrative than to the genres of STEM and architecture. These three emergent directions have profound implications for educators wishing to incorporate digital, multimodal composing, especially in English for Special Purposes classrooms. For example, the role multimodal tasks can play in promoting language development has implications for how specialised knowledge can be effectively scaffolded in the ESP classroom. It also demonstrates the usefulness of multimodal literacy in supporting and extending alphabetic literacy, particularly with regard to the use and interpretation of technical concepts. Further, the significance of such tasks being able to develop learners as social agents means, among other outcomes, that students are more able to meet the newly altered accreditation standards of the Common European Framework of Reference for Languages (CEFR). This has implications for the number and quality of professional and academic opportunities available to students, because the CEFR is the preeminent language certification framework in Europe. It also has profound implications for language pedagogy more broadly, because in Germany in particular, curricular decisions and educational standards draw heavily upon the level descriptors of the CEFR (e.g., Tschirner, 2008; Burmeister et al., 2016). The findings have further implications for theorising the nature of disciplinary modalities. For example, students being apprenticed into the construction industry, such as those who form the basis of this project, are and will be expected to create and interpret architectural and civil engineering models in their disciplinary studies and future professional lives. Building such competencies in their related English language courses can bolster and enhance these essential skills, and multimodal tasks involving such models can provide practical opportunities for classroom activities to reflect authentic professional practice. Finally, findings suggest that multimodal assessment tasks such as this one offer the possibility of reconsidering what is ‘valid’ and for whom. The frequent recurrence of mediated focalisation in the dataset, that is, the use of particular framing techniques to symbolically conflate the student composers with their audiences, permits certain conjectures. For example, it will be argued that the students are selecting this framing technique deliberately, perhaps in order to participate in an alternative performance of professionalism, one that is aligned more closely with apprentices than knowledge-authorities. This has implications for what it means to perform professionalism not only in the ESP classroom, but in STEM and architecture communication more broadly

Nachbauprobleme bei Apfelkulturen

Bei wiederholtem Anbau von Obstbäumen am gleichen Standort wird häufig verminderter Wuchs und reduzierter Ertrag beobachtet. Dieses Phänomen wird als Nachbauproblem oder Bodenmüdigkeit bezeichnet. Auch Schweizer Apfelproduzenten sind davon betroffen. Die ACW untersucht mögliche Ursachen

Modulorientiertes Produktlinien Engineering für den modellbasierten Elektrik/Elektronik-Architekturentwurf

Heutzutage werden E/E-Architekturen modellbasiert entworfen, um in der Fahrzeugentwicklung frühzeitig den Reifegrad für die fahrzeugweite Vernetzung und Integration von Elektrik, Elektronik und Software abzusichern. Das methodische Konzept und die praktische Umsetzung durch das Modulorientierte Produktlinien Engineering ermöglicht eine Erhöhung der Modellierungseffizienz und der Modellqualität sowie eine Anwenderunterstützung für die Modellierung der komplexen E/E-Architekturmodelle

Proposta de utilização do modelo de transporte para a tomada de decisão no planejamento da produção : desenvolvimento de um aplicativo

Orientadora : Profª Drª Neida Maria Patias VolpiDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Produção. Defesa: Curitiba, 2015Inclui referênciasÁrea de concentraçãoResumo: A proposta deste trabalho é o uso do modelo de transporte como técnica para o planejamento da produção. Um bom plano de produção é aquele que atende as demandas dentro do prazo, respeita a capacidade dos recursos disponíveis e minimiza os custos de produção. Este trabalho busca através da Pesquisa Operacional, adaptar o modelo do transporte ao planejamento da produção além de gerar um aplicativo que sirva de suporte aos tomadores de decisão, fornecendo informações para análise de diferentes cenários do sistema produtivo. Esse aplicativo trabalha com um horizonte de planejamento e custos diferenciados por período e modo de produção, permite estoque e backlogging, avaliar alterações no planejamento no caso de mudanças na capacidade ou demanda, além de ter fácil utilização, possibilitando assim o gerenciamento fornecendo informações ao usuário. Palavras-chave: Planejamento da Produção; Programação Linear Inteira; Modelo de Transporte.Abstract: The proposal of this paper is the use of transportation model as a technique for production planning. A good production plan is one that attend to demands on time, respects the capacity of available resources and minimizes production costs. This paper uses the Operational Research to adapt the transportation model to production planning, and also to generate an application that serves as a support to decision makers, providing information to analyze different scenarios of the production system. This application works with a planning horizon and differentiated costs by period and mode of production, allow inventory and backlogging, measure changes of the plan in cases where capacity or demand changes, in addition to ease of use, allowing management by providing information to the user. Keywords: Production Planning; Integer Linear Programming; Transportation Model

Multilevel regression modelling to investigate variation in disease prevalence across locations

In this article, we show how to investigate the role of individual (personal) risk factors in outcome prevalence in multicentre studies with multilevel modelling. The variation in outcome prevalence is modelled by introducing a random intercept. In the next step, the empty model is compared with the model containing the risk factor(s). Because the outcome is dichotomous, this comparison can only be carried out after having rescaled the models’ parameter values to the variance of an underlying continuous variable. We illustrate this approach with data from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC) and provide a corresponding Stata do-file