Die Qualität von Nutzpflanzen ist von zahlreichen Einflussfaktoren wie beispielsweise Lagerbedingungen und Sorteneigenschaften abhängig. Um Qualitätsmängel zu minimieren und Absatzchancen von Nutzpflanzen zu steigern sind umfangreiche Analysen hinsichtlich ihrer stofflichen Zusammensetzung notwendig. Chromatographische Techniken gekoppelt an ein Massenspektrometer und die Kernspinresonanzspektroskopie wurden dafür bislang verwendet. In der vorliegenden Arbeit wurde ein Gaschromatograph an ein Flugzeitmassenspektrometer (GC-TOF-MS) gekoppelt, um physiologische Prozesse bzw. Eigenschaften (die Schwarzfleckigkeit, die Chipsbräunung, das Physiologische Alter und die Keimhemmung) von Nutzpflanzen aufzuklären. Als Pflanzenmodell wurde dafür die Kartoffelknolle verwendet. Dazu wurden neue analytische Lösungsansätze entwickelt, die eine zielgerichtete Auswertung einer Vielzahl von Proben, die Etablierung einer umfangreichen Referenzspektrenbibliothek und die sichere Archivierung aller experimentellen Daten umfassen. Das Verfahren der Probenvorbereitung wurde soweit modifiziert, dass gering konzentrierte Substanzen mittels GC-TOF-MS analysiert werden können. Dadurch wurde das durch die Probenvorbereitung limitierte Substanzspektrum erweitert. Anhand dieser Lösungsansätze wurden physiologisch relevante Stoffwechselprodukte identifiziert, welche indikativ (klassifizierend) bzw. prädiktiv (vorhersagend) für die physiologischen Prozesse sind. Für die Schwarzfleckigkeitsneigung und die Chipseignung wurde jeweils ein biochemisches Modell zur Vorhersage dieser Prozesse aufgestellt und auf eine Züchtungspopulation übertragen. Ferner wurden für die Schwarzfleckigkeit Stoffwechselprodukte des Respirationsstoffwechsels identifiziert sowie Aminosäuren, Glycerollipide und Phenylpropanoide für das Physiologische Alter als relevant erachtet. Das physiologische Altern konnte durch die Anwendung höherer Temperaturen beschleunigt werden. Durch Anwendung von Keimhemmern (Kümmelöl, Chlorpropham) wurde eine Verzögerung des physiologischen Alterns beobachtet. Die Applikation von Kümmelöl erwies sich dabei als besonders vorteilhaft. Kümmelöl behandelte Knollen wiesen im Vergleich zu unbehandelten Knollen nur Veränderungen im Aminosäure-, Zucker- und Sekundärstoffwechsel auf. Chlorpropham behandelte Knollen wiesen einen ähnlichen Stoffwechsel wie die unbehandelten Knollen auf. Für die bislang noch nicht identifizierten Stoffwechselprodukte wurden im Rahmen dieser Arbeit das Verfahren der „gezielten An-/Abreicherung“, der „gepaarten NMR/GC-TOF-MS Analyse“ und das „Entscheidungsbaumverfahren“ entwickelt. Diese ermöglichen eine Klassifizierung von GC-MS Signalen im Hinblick auf ihre chemische Funktionalität. Das Verfahren der gekoppelten NMR/GC-TOF-MS Analyse erwies sich dabei als besonders erfolgversprechend, da es eine Aufklärung bislang unbekannter gaschromatographischer Signale ermöglicht. In der vorliegenden Arbeit wurden neue Stoffwechselprodukte in der Kartoffelknolle identifiziert, wodurch ein wertvoller Beitrag zur Analytik der Metabolomik geleistet wurde. / Several factors influence the quality of crops. These include particular storage conditions and cultivar properties. Minimization of quality defects requires the employment of comprehensive metabolic analysis to enhance the marketing potential of crops. From this point of view chromatographic techniques coupled either with a mass spectrometer or the combination with nuclear magnetic resonance spectroscopy have been successfully applied to solve the main tasks. In the present work, a gas chromatograph was coupled to a time of flight mass spectrometer (GC-TOF-MS) to analyze physiological processes and attitudes of crops like black spot bruising, chips tanning, physiological aging, and sprouting inhibition. For this purpose the potato tuber was employed as a model plant. Therefore, new analytical approaches were developed comprising the targeted analysis of a multitude of samples, the establishment of a comprehensive mass spectral reference library and the built up of a secure archival storage system. Furthermore, the sample preparation protocol was modified to analyze trace components with the help of GC-TOF-MS as well. This helped to extend the discovery of more endogenous metabolites. These analytical approaches were required to identify physiological relevant indicative and predictive metabolites. Consequently, a biochemical model was build up for the process of black spot bruising and chips tanning respectively. These models could be applied to an unknown breeding progeny. Metabolites of the respiratory chain were identified as relevant for the process of black spot bruising whereas amino acids, lipids and phenylpropanoids were of high importance for the process of physiological aging.  The process of physiological aging could be accelerated while applying higher temperatures and could be delayed while applying sprouting inhibitors, like caraway oil and chlorpropham. Compared to chlorpropham, caraway oil exhibited more advantages with respect to storage attitudes although it caused significant changes in the amino acid, sugar and secondary metabolism during a common storage period. However, the chlorpropham treated tubers showed a similar phenotype in comparison to the control tubers. In addition, several methods were developed with respect to the classification of yet unidentified signals. These cover the decision tree process, the targeted enrichment and depletion of specific metabolites with the help of solid phase extraction and the paired NMR and GC-MS analyses. The paired NMR and GC-MS analysis appears very promising because it allows for the identification of unknown GC-MS signals. Thus, this work makes a valuable contribution to the analytics of the metabolome, as new metabolites could be identified which are of physiological relevance for the potato tuber.

<p>The driving force of conducting the two studies presented in this thesis is to examine ways that conceptual understanding and problem solving could be part of mathematics teaching, and through that, part of students' mathematical knowledge. The specific aims of the thesis are: 1) to characterize the classroom discourse of two, apparently similar, problem solving courses in teacher education and 2) to discuss the possibilities of developing two analytical approaches - the communicational approach to cognition and the dialogical approach - used for studying mathematical discourse. The two aims are elaborated on by means of data collected through audiotaped recordings and field notes from observations of problem-solving activities in engineering and teacher education. In relation to the first aim, the analysis of the classroom discourse within the two courses makes it clear that both courses displayed different kinds of discourse that could be broadly categorized in terms of: subject-oriented, didactically oriented, and problem solving oriented discourses. However, the comparisons between the two courses reveal a marked difference in the distribution of these categories of discourse. It is suggested that the introduction of explicit conceptual frameworks in teaching is of crucial importance for the topical focus of the classroom discourse, and for prospective teachers' opportunity to engage in mathematical productive discourse. The analyses of the two approaches for studying mathematical discourse reveal that the two frameworks can be further developed and the study also indicates ways in which such development can be achieved using a theory of contextualization and theories of mathematical learning. Finally, the thesis discusses theoretical and practical implications of the results, foregrounding issues of importance for the research on mathematical discourse, and for teachers and teacher educators involved in designing instructions for mathematical problem solving.</p>

The driving force of conducting the two studies presented in this thesis is to examine ways that conceptual understanding and problem solving could be part of mathematics teaching, and through that, part of students' mathematical knowledge. The specific aims of the thesis are: 1) to characterize the classroom discourse of two, apparently similar, problem solving courses in teacher education and 2) to discuss the possibilities of developing two analytical approaches - the communicational approach to cognition and the dialogical approach - used for studying mathematical discourse. The two aims are elaborated on by means of data collected through audiotaped recordings and field notes from observations of problem-solving activities in engineering and teacher education. In relation to the first aim, the analysis of the classroom discourse within the two courses makes it clear that both courses displayed different kinds of discourse that could be broadly categorized in terms of: subject-oriented, didactically oriented, and problem solving oriented discourses. However, the comparisons between the two courses reveal a marked difference in the distribution of these categories of discourse. It is suggested that the introduction of explicit conceptual frameworks in teaching is of crucial importance for the topical focus of the classroom discourse, and for prospective teachers' opportunity to engage in mathematical productive discourse. The analyses of the two approaches for studying mathematical discourse reveal that the two frameworks can be further developed and the study also indicates ways in which such development can be achieved using a theory of contextualization and theories of mathematical learning. Finally, the thesis discusses theoretical and practical implications of the results, foregrounding issues of importance for the research on mathematical discourse, and for teachers and teacher educators involved in designing instructions for mathematical problem solving.

This dissertation explores the influences on individual decision making in a complex, real world context – the New Zealand wool supply chain. It asks two fundamental questions, first, how do decision makers make decisions in their everyday settings and, second, how is decision making learned and improved through experience and contextual factors. Two contextual aspects of decision making were also examined; these included whether decision making processes varied as a result of uncertainty and risky surroundings, or in cooperative and competitive environments. Further examination included revealing how being a member of a (multi-layered) group influences individual decision making. In-depth qualitative interviewing of sheep farmers, and associated supply chain members in the wool industry was undertaken. Three key decision journeys were explored from both the 'psychological' and the 'social' schools of social psychology in order to give detail on the flow of decision making influences through human systems (whether entities were present, or implied). One of the main aspects of this study was to employ, by analogy, an analysis inspired by the concept of multi-level selection from evolutionary theory as a means of understanding decision making in such a complex, layered system. Other contributions include commentary on the nature of social psychological studies of decision making, suggestions for the expansion of naturalistic decision making to include processes occurring on more than one 'level' of context, the framing of information in the media and the judgment of information sources on the part of experienced and inexperienced farmers, and, the role that globalization may play in driving decision making behaviour.

Dans cette thèse nous étudions les propriétés d'ondes stationnaires dans des structures composées d'une couche diélectrique nonlinéaire de type Kerr et des couches métalliques et diélectriques linéaires. Nous élaborons différents modèles pour étudier les propriétées de plasmons-solitons dans deux types de structures : (i) une région diélectrique nonlinéaire semi-infinie, des couches de métal et de diélectrique linéaires et (ii) une couche de diélectrique nonlinéaire d'épaisseur finie entre deux régions métalliques (guide d'onde métallique à coeur nonlinéaire). Pour le premier type de structures, nous montrons qu'en utilisant une structure à quatre couches, il est possible d'obtenir des plasmons-solitons de basses puissance. Pour des guides d'onde métalliques à coeur nonlinéaire, nous trouvons de modes d'ordres supérieurs. Pour certains des modes symétriques, nous observons une bifurcation par brisure de symétrie donnant naissance à des modes asymétriques dans une structure symétrique. / In this PhD thesis, we study the properties of stationary transverse magnetic polarized waves in structures composed of a Kerr-type nonlinear dielectric layer, metal and linear dielectric layers. We develop several models to study the properties of plasmon-soliton waves in two types of structures: a semi-infinite nonlinear dielectric in contact with metal and linear dielectric layers and a finite-size nonlinear dielectric layer sandwiched between two metal regions (nonlinear slot waveguide). Our models allow us to compute the nonlinear dispersion relations and the corresponding field profiles. For the first type of structure, we prove that using the four-layer structures that we propose, it is possible to obtain plasmon-soliton waves at the power levels. For nonlinear slot waveguide structures, we discover the existence of new, higher order modes. For some of the symmetric modes, we observe a symmetry breaking bifurcation giving birth to asymmetric modes in symmetric structure.