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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.
1

Mode of action of vitamin B←1←2 : model studies

Ashwell, Susan January 1989 (has links)
No description available.
2

Les fourmis et les machines : interfacer systèmes vivants et systèmes artificiels / Ants and machines : interfacing living systems and artificial systems

Ponthieu, Raphaël 29 November 2018 (has links)
Au sein du règne animal, les insectes sociaux fascinent les humains. En particulier les fourmis, capables de s’adapter à des environnements très variés et d’utiliser le biotope à leur avantage. L’observation de pratiques que l’on a longtemps pensées exclusives à l’humain telles que l’agriculture (de champignons) ou l’élevage (de pucerons) ne rend que plus urgente l’envie de comprendre de quelle manière s’opèrent ces phénomènes. Il s’avère que les fourmis réalisent certaines tâches de manière différente des humains. Par exemple pour trouver le chemin le plus court vers de la nourriture ou le meilleur nid vers lequel migrer, la colonie peut faire son choix de manière collective, décentralisée et sans avoir besoin que les individus ne comparent les options. Mon travail a consisté à élaborer et utiliser de nouvelles méthodes pour l’étude des fourmis. Deux objectifs complémentaires ont été fixés pour le conduire : réaliser un système biohybride et essayer de contrôler le comportement des fourmis. Le premier objectif consiste à se demander ce qu’il pourrait se passer si l’on connectait une colonie de fourmis à un ordinateur. Il s’agissait dans un premier temps de donner la vue à l’ordinateur sur ce que fait la colonie de fourmis. Il fallait ensuite fournir à l’ordinateur des moyens d’action sur la colonie.Pour cela, j’ai conçu et mis à l’épreuve des outils de suivi de l’activité de la colonie, ainsi que des environnements modulaires où évoluent les fourmis. J’ai créé un dispositif de suivi et d’analyse d’image embarquée sur micro-ordinateur et grâce à l’impression 3D j’ai fabriqué des modules de différentes tailles qui peuvent être assemblés afin de former un environnement structurellement varié. Afin que l’ordinateur puisse agir sur les fourmis, j’ai choisi de lui donner la possibilité de modifier les conditions environnementales, en particulier la température. Une fois le système conçu j’ai réalisé des expériences afin de savoir ce que les changements locaux de température induisent sur le comportement des fourmis. La caractérisation du comportement face à des changements de température apporte un éclairage sur la relation des fourmis à leur environnement. Cela a ensuite permis d’explorer les questions de contrôle du comportement des fourmis par une machine. L’usage de la température ayant démontré sa capacité à moduler localement le taux de présence des fourmis, j’ai pu ensuite prouver qu’il était possible de confiner une fourmi dans une zone prédéfinie. Enfin, j’ai mis en place une boucle de contrôle où la température utilisée pour confiner la fourmi dépend de son activité en temps réel. Cette dernière expérience permet de mettre en lumière la complexité du rapport des fourmis à leur environnement et ouvre de nouvelles perspectives dans la continuité de ce travail. Cette thèse a permis d’éclaircir des thématiques nouvelles appliquées aux fourmis, qui sont celles des systèmes biohybrides et du contrôle du vivant et de mettre en évidence les directions accessibles à l’avenir. Au cours de cette recherche, de nombreux outils ont été conçus. Les prototypes fonctionnels d’environnement modulaires ont démontré la pertinence de l’utilisation d’imprimante 3D pour l’étude des fourmis. Les différents outils de suivi, d’enregistrement et de traitement des données vidéos fournissent de nouvelles possibilités expérimentales inédites et pourront être utilisés pour d’autres études, notamment au temps long. Les dispositifs de contrôle de la température ont de même été conçus par des moyens propres au prototypage rapide, ce qui les rend accessibles, modulables et reproductibles dans une démarche open source / Within the animal kingdom social insects fascinate humans. Especially ants, which are capable of adapting to various environments and taking advantage of their biotopes. Observing practices that we would have thought to be exclusive to humans – such as farming (of mushrooms) or breeding (of aphids) – spurs the will to understand by which mean ants operate. It turns out that ants achieve certain tasks in different ways than humans. For instance, to find the shortest path to a food source, or the best nest to migrate to; the colony can make a collective decision, decentralized and without the need of direct comparisons by individuals. My work has consisted of the elaboration and use of new methods to study ants. Two complementary objectives have been chosen to drive the work: implementation of a biohybrid system and assessing the means of and limits to controlling the behaviour of ants. The first objective consists of asking ourselves what will happen if we connected an ant colony with a computer For this I have designed apparatus that permit interaction between those two entities. It involved giving sight to the computer into what the colony was doing, then providing ways for the computer to act on the colony. To do so, I designed and tried out tools to monitor the activity of colonies as well as modular environments which ants can inhabit. I designed an embedded system that records and analyses activity of ant colonies on a micro-computer. I designed and 3D printed modules of various sizes that can be assembled together to form a structurally varied environment. For the computer to be able to act upon ant behaviour, I chose to endow it with the capability of modifying environmental conditions, at particular temperatures. Once the system was built, I conducted experiments to assess how local changes of temperature affect ant behaviour. This characterisation of behaviour under temperature changes sheds light on the relation of ants with their environment. This permitted the exploration of questions of control of behaviour of ants by a machine. The use of temperature having proved its capacity to modulate the local occupancy density, I then have been able to show that it was possible to confine an ant in a set location. Finally, I implemented a closed feedback loop system, in which the temperature used to confine the ant is dependent on the ant activity in real time. This last experiment shed light on the complexity of the dynamic relation between ants and their environments and opened new perspectives for future investigations. During this research, many tools were developed. Functional prototypes of moduary environments have demonstrated the relevance of using 3D printers for the study of ants. The various tools for monitoring, recording and processing video data provide new and innovative experimental possibilities and can be used for other studies, especially over long periods of time. Temperature control devices have as well been designed using rapid prototyping tools, making them accessible, scalable and reproducible in an open source approach.
3

Wirkung von Oberflächenladungen auf Zellen - Beobachtungen in der Nanodimension / Effects of surface charges on living cells – Observations in the nano-dimension

Funk, Richard H. W., Monsees, Thomas 31 August 2007 (has links) (PDF)
Living organisms and in particular cells actively structure their inner world in the nano-dimension. Not only organelles are formed by the cells, but also their direct environment, the extracellular matrix. Recent studies show that electrical potentials are similarly important in the process of adhesion and directed migration. Nanostructured charge patterns may also influence the interactions between cells, tissues and implants used in therapy. Even small differences in the structure of charged molecules can already change the behaviour of cells drastically. Inside the cell, furthermore, very small topographic features are decisive: In ion channels, dimensions of 1/100 nm are essential for their function. Such precise structures are nowadays still a technical challenge. When modelling such cellular “electronics” using chip technology, we can learn a lot from nature’s tricks in cell physiology. / Lebende Organismen und insbesondere die einzelnen Zellen selbst sind Meister in der aktiven Strukturierung auf Nanoebene. So bilden die Zellen nicht nur ihr reichhaltiges „Innenleben“ in dieser Dimension, sondern strukturieren auch ihre direkte Umgebung, den extrazellulären Bereich. Bei der Haftung und gerichteten Bewegung der Zellen scheinen nach neueren Befunden auch elektrische Potenziale und Oberflächenladungen mit Mustern bis „hinab“ auf die Nanoebene eine Rolle zu spielen. Nanostrukturierte Muster von Ladungen können so auch die Wechselwirkung von Zellen und Geweben mit Implantaten beeinflussen. Diese Beobachtungen führen wieder zurück zu den Zellen selbst, die zum Beispiel im Falle von Ionenkanälen mit hundertstel Nanometer Genauigkeit Topographie und Potenziale kontrollieren. Solche Strukturen könnten zukünftig auch über Chiptechnologie modelliert werden – eine Chance, von der Natur zu lernen und dies technisch umzusetzen.
4

Wirkung von Oberflächenladungen auf Zellen - Beobachtungen in der Nanodimension

Funk, Richard H. W., Monsees, Thomas 31 August 2007 (has links)
Living organisms and in particular cells actively structure their inner world in the nano-dimension. Not only organelles are formed by the cells, but also their direct environment, the extracellular matrix. Recent studies show that electrical potentials are similarly important in the process of adhesion and directed migration. Nanostructured charge patterns may also influence the interactions between cells, tissues and implants used in therapy. Even small differences in the structure of charged molecules can already change the behaviour of cells drastically. Inside the cell, furthermore, very small topographic features are decisive: In ion channels, dimensions of 1/100 nm are essential for their function. Such precise structures are nowadays still a technical challenge. When modelling such cellular “electronics” using chip technology, we can learn a lot from nature’s tricks in cell physiology. / Lebende Organismen und insbesondere die einzelnen Zellen selbst sind Meister in der aktiven Strukturierung auf Nanoebene. So bilden die Zellen nicht nur ihr reichhaltiges „Innenleben“ in dieser Dimension, sondern strukturieren auch ihre direkte Umgebung, den extrazellulären Bereich. Bei der Haftung und gerichteten Bewegung der Zellen scheinen nach neueren Befunden auch elektrische Potenziale und Oberflächenladungen mit Mustern bis „hinab“ auf die Nanoebene eine Rolle zu spielen. Nanostrukturierte Muster von Ladungen können so auch die Wechselwirkung von Zellen und Geweben mit Implantaten beeinflussen. Diese Beobachtungen führen wieder zurück zu den Zellen selbst, die zum Beispiel im Falle von Ionenkanälen mit hundertstel Nanometer Genauigkeit Topographie und Potenziale kontrollieren. Solche Strukturen könnten zukünftig auch über Chiptechnologie modelliert werden – eine Chance, von der Natur zu lernen und dies technisch umzusetzen.
5

The Effect Of Multiple Intelligences Based Instruction On Students

Sakir, Tuncay 01 February 2013 (has links) (PDF)
The main purpose of this study was to compare the effectiveness of multiple intelligences based instruction (MIBI) over traditionally designed instruction on ninth grade students&rsquo / achievement in the unit of basic compounds of living organisms concepts and attitude toward biology as a school subject. In addition, the effect of gender difference on achievement in the unit and attitudes toward biology were investigated. Students&rsquo / science process skills were also investigated. 59 ninth grade students from two different classes taught by the same teacher at a public Anatolian high school in Kirsehir were enrolled in the study during first semester of 2011-2012 academic years. The classes were randomly assigned as control group and experimental group. While control group students were instructed by traditionally designed biology instruction, the experimental group students were instructed with MIBI over a period of ten weeks. Basic compounds of living organisms achievement test and attitude scale toward biology were given to both groups as a pre-test and post-test. Science Process skills test was given at the beginning of the study to determine students&rsquo / science process skills. Interviews were hold with some students in the experimental group and the teacher to get their opinions about the implementation of MI based instruction. Multivariate Analysis of Covariance (MANCOVA) was used to analyze the data. The results of the study revealed that MIBI compared to traditional instruction was more effective to improve students&rsquo / achievement in the unit of basic compounds of living organisms. However there was no significant effect of MIBI on students&rsquo / attitude toward biology. Moreover there was no significant effect of gender difference on both students&rsquo / achievement in the unit and attitudes toward biology. The results of interview showed that both students and the teacher had positive opinions toward MIBI.
6

Living systems on heterogeneous cellular substrate : contribution to a better understanding of dynamic interfaces of fungal pigmentation and paper in biodeterioration of cultural heritage / Organismes vivants dans des substrats cellulaires hétérogènes : contribution à une meilleure compréhension des interfaces dynamiques de pigmentation fongique et du papier dans la bio-détérioration du patrimoine culturel

Szczepanowska, Hanna M. 04 October 2012 (has links)
La bio-détérioration des documents culturels compte parmi les types de détériorations les plus complexes que sont amenés à subir ces objets; et ce, parce qu’elle implique des organismes vivants ainsi que la conjonction de nombreux facteurs. Il existe différentes formes de biodétérioration; les taches de substrat (support?) engendrées par des champignons pigmentés en sont un exemple. Une multitude d’actions se développent aux “interfaces” entre le substrat (support?) et les champignons, depuis le premier contact avec les spores, en passant par la prolifération fongique, jusqu’aux interactions avec l’environnement. L’analyse multi-échelle et multisensorielle de l’interface entre les moisissures pigmentées noires et le support papier est le sujet de ces thèses. Deux types de pigmentations fongiques noires ont fait l’objet d’une analyse; la première apparaissait spontanément sur les œuvres d’art , la deuxième résultait d’une pigmentation déclenchée en biosimulation, sur des papiers connus, dans un environnement maitrisé. Les caractéristiques des papiers telles que le relief et la structure de la surface, la morphologie des champignons, les processus de dépôt de la biomasse pigmentée, ainsi que la prolifération fongique, ont fait l’objet de multiples examens, tant en termes d’instruments que de méthodes :microscopie à lumière transmise, microscopie électronique à balayage (MEB) dans une chambre à pression variable, microscopie confocale à balayage laser, profilomètre confocal à lumière blanche, microtomographie aux rayons L’objectif ultime étant de développer une stratégie de préservation des objets du patrimoine culturel bio-détériorés, le choix des instruments et des méthodes d’analyse était dicté par un souci pratique qui limitait l’échantilllonage des éléments analysés. Ce travail constitue une première tentative afin de mieux comprendre les forces en présence au niveau des “interfaces”, dans le cas des taches sur le papier dues aux champignons. / Biodeterioration of cultural materials is one of the most complex types of deteriorations that cultural materials are subjected to mainly, because it involves living organisms and synergy of many factors. There are different forms of biodeterioration, stains of substrate caused by pigmented fungi is one of them. Multitude of events occurs at interfaces between substrate and fungi, from the moment of spores’ first contact with surfaces, next fugal growth and their responses to the environment. Multiscale and multisensory analysis of interfaces between black pigmented fungi and paper substrate was the subject of these theses. Two types of black fungal pigmentations were analyzed; one that occurred on the original artworks the other one was induced in biosymulation on known papers in controlled environment. Paper characteristics, such as surface topography and structure, morphology of fungi and patterns of their pigmented bio-mass deposition as well as fungal growth were examined with an array of analytical instruments and methods: transmitted light microscopy, scanning electron microscopy in variable pressure, confocal laser scanning microscopy, white light confocal profilometer and X-ray microtomography. The ultimate goal was to develop a preservation strategy for biodeteriorated cultural heritage material; therefore the choice of the analytical methods and instruments was dictated by real-life protocols that limit sampling of cultural materials. This works is the first attempt towards a better understanding of interfacial forces in fungal stains on paper.
7

An Investigation Of The Teaching-learning Process Based On Multiple Intelligence Theory In A High- School Biology Course

Presley, Arzu Irfan 01 June 2005 (has links) (PDF)
This study sought to investigate the effects of multiple intelligences based instruction (MIBI) and learning styles on ninth graders&amp / #8217 / attitudes toward biology, biology achievement, and overall multiple intelligences. This experimental research was conducted in the second term of 2002-2003 educational year in Eregli high school. The sample involved in the study consisted of 64 students from the two different ninth grade classes taught by the same teacher. One class was assigned as the experimental group in which students were exposed to MIBI, whereas the other class was assigned as the control group in which students were exposed to traditional instruction in the unit of diversity and classification of living organisms. The data were obtained from attitudes toward biology scale, unit achievement test, multiple intelligences and Kolb&amp / #8217 / s learning style inventories, interviews with the students and the teacher, and observations in the experimental classroom during the treatment. Multivariate Analysis of Covariance was used for the quantitative data obtained from measuring tools. Results indicated that there was a significant effect of MIBI on students&amp / #8217 / attitudes toward biology and biology achievement, but there was not any significant effect of MIBI on students&amp / #8217 / overall multiple intelligences. In addition, there was not any significant effect of the students&amp / #8217 / learning styles on their attitudes toward biology, biology achievement, or overall multiple intelligences. Moreover, interpretations of the interviews with the students and the teacher, and the observations of the experimental classroom indicated that MIBI had positive contributions on teaching and learning process.
8

Měření iontových polí / Ion fields measurement

Svozil, Radek January 2009 (has links)
The aim of this semester project is the introduction to the problematic of ion fields, where and under what circumstances they originate and extinct and the techniques of measurement. The project will deal with the atmosphere and the electrical field of the Earth. I will consider the composition of the atmosphere and the principles of origin and extinction of ions. I am going to mention the division of ions and their influence on the living organisms. Another topic to be dealt with is the methods for measuring the air ions and the small currents. Gradually we are going to learn the known methods of the measuring of air ions. We are going to get a closer look at the method of measuring with the cylindrical aspiration capacitor. We are also going to deal with the problem of measuring very low currents, where they originate and how it is possible to compensate them. The outcome of the project should be the concept and later the creation of the sonde for the measuring of the ion fields itself.

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