Blüten und Bestäuber

In der vorliegenden Arbeit wurde das Thema Blütenökologie im Rahmen der Didaktischen Rekonstruktion untersucht und didaktisch aufbereitet. In der fachlichen Klärung wurden die besonders „unterrichtsrelevanten“ Teilgebiete kritisch herausgearbeitet. In einem weiteren Arbeitsschritt wurden die Vorstellungen von sieben SchülerInnen der 1. Klasse Unterstufe (5. Schulstufe) mithilfe qualitativer Leitfaden-orientierter Interviews erhoben. Die Interviews wurden in Folge nach den Regeln der qualitativen Inhaltsanalyse ausgewertet. Die herausgefilterten Konzepte und Denkfiguren der SchülerInnen liefern einen für den Unterricht wertvollen Anhaltspunkt über vorhandene Vorstellungen und Probleme der SchülerInnen in Bezug auf Blütenökologie und Bestäubung. Auf der Basis der fachlichen Klärung und der Schülervorstellungen erfolgt die Präsentation eines Unterrichtsmodells, das für die Durchführung in Schulen oder botanischen Gärten geeignet ist. Kernstück des Unterrichtsentwurfs ist der Einsatz von selbst gefertigten blütenbiologischen Modellen und dazugehörigen Arbeitsaufträgen.This thesis looks at floral ecology and pollination, using the methods of Educational Reconstruction. It provides proposals to teach these topics in school lessons. In the first part, the focus lies on various aspects of floral ecology and pollination consid-ered most relevant. The second part presents the individual ideas and concepts of seven 11-year-old pupils who were interviewed for that purpose. Those interviews were then analyzed according to qualitative content analysis and the findings are used as teaching-related reference points for existing ideas or misconceptions. On the basis of both the pupils’ ideas and professional explanations of this topic a teaching model is developed which can be used in schools as well as in botanic gardens. The centerpiece of this model is the use of self-made models of various flowers connected with specific tasks

The Numerical Simulation Application for Fire-Tube Boiler Heating Surface Safety Evaluation

The numerical simulation is applied for fire-tube boiler heating surface safety estimation. Thermal processes in an inflatable fire-tube furnace during its emergency operation were simulated using the finite volume method with Euler approximation and the implicit pressure based algorithm. Study results reproduce failures connected with increasing of impasse aerodynamic resistance. The method of these failures prediction is suggested. Simulation has shown that entering the amount of coolant into combustion volume results in burner fan incapability to overcome the impasse resistance of the furnace. The simulation results are visually confirmed during the inspection of emergency boilers

Variabilidad hidrológica de mesoescala inducida por los vientos del noroeste sobre la plataforma continental del golfo de Vizcaya

On the French continental shelf of the Bay of Biscay the variability of the surface salinity distribution has been mainly investigated at the seasonal and inter-annual scales. Here, new mesoscale features such as lower-salinity lenses observed in model results are investigated by hydrological measurements acquired during 8 cruises (1997-2000). These lenses are 50-80 km wide and ~30 m thick and occur during westerly to northerly wind events that push offshore the less saline water of river plumes. These water masses detached from the coast are replaced with upwelled saltier water at the coast, so coastal upwelling is often observed at the same time along Landes and southern Brittany coasts. We show that in addition to the influence of seasonal and inter-annual variability of the wind and river outflows, short term meteorological variability may drive mesoscale structures on this continental shelf.La salinidad de la plataforma continental francesa del golfo de Vizcaya fue estudiada a escalas anuales e interanuales principalmente. A partir de medidas efectuadas durante ocho campañas marinas (1997- 2000) y del empleo de modelos matemáticos han podido estudiarse nuevas estructuras hidrológicas aisladas de menor salinidad en forma de lentejas. Estas lentejas han medido entre 50 y 80 km de diámetro y 30 m de espesor. Este fenómeno ha sido observado durante, o después, de fuertes vientos del cuadrante oeste o noroeste que favorecen el desplazamiento del agua desalada de las plumas fluviales hacia el mar abierto. Al separarse de la pluma, estas masas de agua son remplazadas por otra, mas salada, que resurge en la zona costera. De esta manera, puedan observarse simultáneamente afloramientos costeros en las regiónes francesas de Landes y del sur de Bretaña. Se muestra que, además de la variabilidad anual e interanual de los vientos y del caudal de los ríos, los fenómenos meteorológicos a corto plazo pueden condicionar las estructuras hidrológicas de la meso escala de la plataforma continental

Image and information management system

A system and methods through which pictorial views of an object's configuration, arranged in a hierarchical fashion, are navigated by a person to establish a visual context within the configuration. The visual context is automatically translated by the system into a set of search parameters driving retrieval of structured data and content (images, documents, multimedia, etc.) associated with the specific context. The system places hot spots, or actionable regions, on various portions of the pictorials representing the object. When a user interacts with an actionable region, a more detailed pictorial from the hierarchy is presented representing that portion of the object, along with real-time feedback in the form of a popup pane containing information about that region, and counts-by-type reflecting the number of items that are available within the system associated with the specific context and search filters established at that point in time

Image and information management system

A system and methods through which pictorial views of an object's configuration, arranged in a hierarchical fashion, are navigated by a person to establish a visual context within the configuration. The visual context is automatically translated by the system into a set of search parameters driving retrieval of structured data and content (images, documents, multimedia, etc.) associated with the specific context. The system places ''hot spots'', or actionable regions, on various portions of the pictorials representing the object. When a user interacts with an actionable region, a more detailed pictorial from the hierarchy is presented representing that portion of the object, along with real-time feedback in the form of a popup pane containing information about that region, and counts-by-type reflecting the number of items that are available within the system associated with the specific context and search filters established at that point in time

Production Mechanism for Quark Gluon Plasma in Heavy Ion Collisions

A general scheme is proposed here to describe the production of semi soft and soft quarks and gluons that form the bulk of the plasma in ultra relativistic heavy ion collisions. We show how to obtain rates as a function of time in a self consistent manner, without any ad-hoc assumption. All the required features - the dynamical nature of QCD vacuum, the non-Markovian nature of the production, and quasi particle nature of the partons, and the importance of quantum interference effects are naturally incorporated. We illustrate the results with a realistic albeit toy model and show how almost all the currently employed source terms are unreliable in their predictions. We show the rates in the momentum space and indicate at the end how to extract the full phase-space dependence.Comment: 4 pages, 4 figures, two colum

„Mehr als nur Bestäubung“ – Schülervorstellungen zur Bestäubungsbiologie und deren Implikationen für den Unterricht

ZUSAMMENFASSUNGDer Prozess der Bestäubung stellt einen wichtigen Abschnitt in der sexuellen Vermehrung höherer Pflanzen dar und ist auch essentiell für das Verständnis der Vielfalt der Blütenpflanzen. Darüber hinaus wird  der Bestäubungsbiologie aufgrund der aktuellen Diskussionen rund um das Bienensterben eine besondere Aktualität beigemessen. Eine Erforschung der Schülervorstellungen zu diesem Thema ist somit von großem fachdidaktischem Interesse. In der vorliegenden qualitativen Studie wurden deshalb Schülervorstellungen von sieben Schüler_innen der 5. Schulstufe zur Bestäubungsbiologie mithilfe von leitfadenorientierten Interviews erhoben und in einer qualitativen Inhaltsanalyse ausgewertet. Die Ergebnisse zeigen, dass Lernende nur mangelhaft zwischen Bestäubung und Samenausbreitung unterscheiden und Bestäu-bung häufig als beabsichtigte Handlung der Insekten sehen. Außerdem zeigen die Vorstellungen über den Zusammenhang von Blüten und Besuchern, dass bereits zu Beginn der 5. Schulstufe Vorstellungen zu Anpassung und Angepasstheit vorhanden sind, die im Unterricht zur Evolution berücksichtigt werden müssen. Diese erhobenen Schülervorstellungen werden mit der fachlichen Perspektive in Beziehung gesetzt und daraus ableitbare fachdidaktische Implikationen diskutiert.ABSTRACTThe process of pollination plays a major role in the lifecycle of plants and is important for understanding the variety of flowering plants. Pollination is also a current issue due to the colony collapse disorder of honeybees. Therefore, investigating students’ conceptions about pollination is highly relevant. The present study investigates conceptions of seven students from 5th grade using guided interviews with regard to pollination biology. Results show that students have serious difficulties differentiating between pollination and seed dispersal. Furthermore, there are differences between students’ conceptions and scientific con-ceptions as students often see pollination as a deliberate act of insects. Students’ conceptions about adaptations of flowers and their pollinators indicate that students’ from 5th grade use evolutionary conceptions which have to be considered when teaching evolution. Students’ conceptions will be discussed in relation to the scientific perspective to derive implications for teaching

Becoming-Bertha: virtual difference and repetition in postcolonial 'writing back', a Deleuzian reading of Jean Rhys’s Wide Sargasso Sea

Critical responses to Wide Sargasso Sea have seized upon Rhys’s novel as an exemplary model of writing back. Looking beyond the actual repetitions which recall Brontë’s text, I explore Rhys’s novel as an expression of virtual difference and becomings that exemplify Deleuze’s three syntheses of time. Elaborating the processes of becoming that Deleuze’s third synthesis depicts, Antoinette’s fate emerges not as a violence against an original identity. Rather, what the reader witnesses is a series of becomings or masks, some of which are validated, some of which are not, and it is in the rejection of certain masks, forcing Antoinette to become-Bertha, that the greatest violence lies

Inducible Defenses with a "Twist": Daphnia barbata Abandons Bilateral Symmetry in Response to an Ancient Predator

Predation is one of the most important drivers of natural selection. In consequence a huge variety of anti-predator defenses have evolved in prey species. Under unpredictable and temporally variable predation pressure, the evolution of phenotypically plastic defensive traits is favored. These "inducible defenses", range from changes in behavior, life history, physiology to morphology and can be found in almost all taxa from bacteria to vertebrates. An important group of model organisms in ecological, evolutionary and environmental research, water fleas of the genus Daphnia (Crustacea: Cladocera), are well known for their ability to respond to predators with an enormous variety of inducible morphological defenses. Here we report on the "twist", a body torsion, as a so far unrecognized inducible morphological defense in Daphnia, expressed by Daphnia barbata exposed to the predatory tadpole shrimp Triops cancriformis. This defense is realized by a twisted carapace with the helmet and the tail spine deviating from the body axis into opposing directions, resulting in a complete abolishment of bilateral symmetry. The twisted morphotype should considerably interfere with the feeding apparatus of the predator, contributing to the effectiveness of the array of defensive traits in D. barbata. As such this study does not only describe a completely novel inducible defense in the genus Daphnia but also presents the first report of a free living Bilateria to flexibly respond to predation risk by abandoning bilateral symmetry

Evaluation of a Novel Thiol–Norbornene-Functionalized Gelatin Hydrogel for Bioprinting of Mesenchymal Stem Cells

Introduction: Three-dimensional bioprinting can be considered as an advancement of the classical tissue engineering concept. For bioprinting, cells have to be dispersed in hydrogels. Recently, a novel semi-synthetic thiolene hydrogel system based on norbornene-functionalized gelatin (GelNB) and thiolated gelatin (GelS) was described that resulted in the photoclick hydrogel GelNB/GelS. In this study, we evaluated the printability and biocompatibility of this hydrogel system towards adipose-tissue-derived mesenchymal stem cells (ASCs). Methods: GelNB/GelS was synthesized with three different crosslinking densities (low, medium and high), resulting in different mechanical properties with moduli of elasticity between 206 Pa and 1383 Pa. These hydrogels were tested for their biocompatibility towards ASCs in terms of their viability, proliferation and differentiation. The extrusion-based bioprinting of ASCs in GelNB/GelS-high was performed to manufacture three-dimensional cubic constructs. Results: All three hydrogels supported the viability, proliferation and chondrogenic differentiation of ASCs to a similar extent. The adipogenic differentiation of ASCs was better supported by the softer hydrogel (GelNB/GelS-low), whereas the osteogenic differentiation was more pronounced in the harder hydrogel (GelNB/GelS-high), indicating that the differentiation fate of ASCs can be influenced via the adaption of the mechanical properties of the GelNB/GelS system. After the ex vivo chondrogenic differentiation and subcutaneous implantation of the bioprinted construct into immunocompromised mice, the production of negatively charged sulfated proteoglycans could be observed with only minimal inflammatory signs in the implanted material. Conclusions: Our results indicate that the GelNB/GelS hydrogels are very well suited for the bioprinting of ASCs and may represent attractive hydrogels for subsequent in vivo tissue engineering applications