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Während Qualifikationen und Kompetenzen, die auf informellem Wege erworben werden, immer mehr Beachtung finden, stellt sowohl deren Darstellung als auch die Anerkennung ein meist unüberwindbares Hindernis für Ausstellende und Erwerbende dar. Vermehrt wird unterdessen von klassisch papiergebundenen auf digitale Teilnahmezertifikate umgestellt, um den Nachweis von Kompetenz- und Qualifikationserwerb zu vereinfachen. In diesem Zusammenhang kann die Verbindung von digitalen Teilnahmezertifikaten und Open Badges einen Mehrwert für die öffentliche Darstellung und Verifikation bieten.
What shapes peace, and how can peace be successfully built in those countries affected by armed conflict? This paper examines mpeacebuilding in the aftermath of civil wars in order to identify the conditions for post-conflict peace. The field of civil war research is
characterised by case studies, comparative analyses and quantitative research, which relate relatively little to each other. Furthermore, the complex dynamics of peacebuilding have hardly been investigated so far. Thus, the question remains of how best to enhance the prospects
of a stable peace in post-conflict societies. Therefore, it is necessary to capture the dynamics of post-conflict peace. This paper aims at helping to narrow these research gaps by 1) presenting the benefits of set theoretic methods for peace and conflict studies; 2) identifying remote conflict environment factors and proximate peacebuilding factors which have an influence on the peacebuilding process and 3) proposing a
set-theoretic multi-method research approach in order to identify the causal structures and mechanisms underlying the complex realm of post-conflict peacebuilding. By implementing this transparent and systematic comparative approach, it will become possible to discover
the dynamics of post-conflict peace.
Answer Set Programming (ASP) is a powerful declarative programming paradigm that has been successfully applied to many different domains. Recently, ASP has also proved successful for hard optimization problems like course timetabling and travel allotment. In this paper, we approach another important task, namely, the shift design problem, aiming at an alignment of a minimum number of shifts in order to meet required numbers of employees (which typically vary for different time periods) in such a way that over- and understaffing is minimized. We provide an ASP encoding of the shift design problem, which, to the best of our knowledge, has not been addressed by ASP yet. Our experimental results demonstrate that ASP is capable of improving the best known solutions to some benchmark problems. Other instances remain challenging and make the shift design problem an interesting benchmark for ASP-based optimization methods.
In this thesis we use integral-field spectroscopy to detect and understand of Lyman α (Lyα) emission from high-redshift galaxies.
Intrinsically the Lyα emission at λ = 1216 Å is the strongest recombination line from galaxies. It arises from the 2p → 1s transition in hydrogen. In star-forming galaxies the line is powered by ionisation of the interstellar gas by hot O- and B- stars. Galaxies with star-formation rates of 1 - 10 Msol/year are expected to have Lyα luminosities of 42 dex - 43 dex (erg/s), corresponding to fluxes ~ -17 dex - -18 dex (erg/s/cm²) at redshifts z~3, where Lyα is easily accessible with ground-based telescopes. However, star-forming galaxies do not show these expected Lyα fluxes. Primarily this is a consequence of the high-absorption cross-section of neutral hydrogen for Lyα photons σ ~ -14 dex (cm²). Therefore, in typical interstellar environments Lyα photons have to undergo a complex radiative transfer. The exact conditions under which Lyα photons can escape a galaxy are poorly understood.
Here we present results from three observational projects. In Chapter 2, we show integral field spectroscopic observations of 14 nearby star-forming galaxies in Balmer α radiation (Hα, λ = 6562.8 Å). These observations were obtained with the Potsdam Multi Aperture Spectrophotometer at the Calar-Alto 3.5m Telescope}. Hα directly traces the intrinsic Lyα radiation field. We present Hα velocity fields and velocity dispersion maps spatially registered onto Hubble Space Telescope Lyα and Hα images. From our observations, we conjecture a causal connection between spatially resolved Hα kinematics and Lyα photometry for individual galaxies. Statistically, we find that dispersion-dominated galaxies are more likely to emit Lyα photons than galaxies where ordered gas-motions dominate. This result indicates that turbulence in actively star-forming systems favours an escape of Lyα radiation.
Not only massive stars can power Lyα radiation, but also non-thermal emission from an accreting super-massive black hole in the galaxy centre. If a galaxy harbours such an active galactic nucleus, the rate of hydrogen-ionising photons can be more than 1000 times higher than that of a typical star-forming galaxy. This radiation can potentially ionise large regions well outside the main stellar body of galaxies. Therefore, it is expected that the neutral hydrogen from these circum-galactic regions shines fluorescently in Lyα. Circum-galactic gas plays a crucial role in galaxy formation. It may act as a reservoir for fuelling star formation, and it is also subject to feedback processes that expel galactic material. If Lyα emission from this circum-galactic medium (CGM) was detected, these important processes could be studied in-situ around high-z galaxies. In Chapter 3, we show observations of five radio-quiet quasars with PMAS to search for possible extended CGM emission in the Lyα line. However, in four of the five objects, we find no significant traces of this emission. In the fifth object, there is evidence for a weak and spatially quite compact Lyα excess at several kpc outside the nucleus. The faintness of these structures is consistent with the idea that radio-quiet quasars typically reside in dark matter haloes of modest masses. While we were not able to detect Lyα CGM emission, our upper limits provide constraints for the new generation of IFS instruments at 8--10m class telescopes.
The Multi Unit Spectroscopic Explorer (MUSE) at ESOs Very Large Telescopeis such an unique instrument. One of the main motivating drivers in its construction was the use as a survey instrument for Lyα emitting galaxies at high-z. Currently, we are conducting such a survey that will cover a total area of ~100 square arcminutes with 1 hour exposures for each 1 square arcminute MUSE pointing. As a first result from this survey we present in Chapter 5 a catalogue of 831 emission-line selected galaxies from a 22.2 square arcminute region in the Chandra Deep Field South. In order to construct the catalogue, we developed and implemented a novel source detection algorithm -- LSDCat -- based on matched filtering for line emission in 3D spectroscopic datasets (Chapter 4). Our catalogue contains 237 Lyα emitting galaxies in the redshift range 3 ≲ z ≲ 6. Only four of those previously had spectroscopic redshifts in the literature. We conclude this thesis with an outlook on the construction of a Lyα luminosity function based on this unique sample (Chapter 6).
For Vibrio cholerae, the coordinated import and export of Na+ is crucial for adaptation to habitats with different osmolarities. We investigated the Na+-extruding branch of the sodium cycle in this human pathogen by in vivo Na-23-NMR spectroscopy. The Na+ extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na+-translocating NADH:quinone oxidoreductase (Na+-NQR). In a V. cholerae deletion mutant devoid of the Na+-NQR encoding genes (nqrA-F), rates of respiratory Na+ extrusion were decreased by a factor of four, but the cytoplasmic Na+ concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (Delta psi, inside negative) and did not grow under hypoosmotic conditions at pH 8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na+/H+ antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na+ concentrations, the Na+-NQR is crucial for generation of a transmembrane voltage to drive the import of H+ by electrogenic Na+/H+ antiporters. Our study provides the basis to understand the role of the Na+-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na+ pump for respiration. (C) 2015 Elsevier B.V. All rights reserved.
Based on theories of scientific discovery learning (SDL) and conceptual change, this study explores students' preconceptions in the domain of torques in physics and the development of these conceptions while learning with a computer-based SDL task. As a framework we used a three-space theory of SDL and focused on model space, which is supposed to contain the current conceptualization/model of the learning domain, and on its change through hypothesis testing and experimenting. Three questions were addressed: (1) What are students' preconceptions of torques before learning about this domain? To do this a multiple-choice test for assessing students' models of torques was developed and given to secondary school students (N = 47) who learned about torques using computer simulations. (2) How do students' models of torques develop during SDL? Working with simulations led to replacement of some misconceptions with physically correct conceptions. (3) Are there differential patterns of model development and if so, how do they relate to students’ use of the simulations? By analyzing individual differences in model development, we found that an intensive use of the simulations was associated with the acquisition of correct conceptions. Thus, the three-space theory provided a useful framework for understanding conceptual change in SDL.
This survey on the theme of Geometry Education (including new technologies) focuses chiefly on the time span since 2008. Based on our review of the research literature published during this time span (in refereed journal articles, conference proceedings and edited books), we have jointly identified seven major threads of contributions that span from the early years of learning (pre-school and primary school) through to post-compulsory education and to the issue of mathematics teacher education for geometry. These threads are as follows: developments and trends in the use of theories; advances in the understanding of visuo spatial reasoning; the use and role of diagrams and gestures; advances in the understanding of the role of digital technologies; advances in the understanding of the teaching and learning of definitions; advances in the understanding of the teaching and learning of the proving process; and, moving beyond traditional Euclidean approaches. Within each theme, we identify relevant research and also offer commentary on future directions.
The three-space theory of problem solving predicts that the quality of a learner's model and the goal specificity of a task interact on knowledge acquisition. In Experiment 1 participants used a computer simulation of a lever system to learn about torques. They either had to test hypotheses (nonspecific goal), or to produce given values for variables (specific goal). In the good- but not in the poor-model condition they saw torque depicted as an area. Results revealed the predicted interaction. A nonspecific goal only resulted in better learning when a good model of torques was provided. In Experiment 2 participants learned to manipulate the inputs of a system to control its outputs. A nonspecific goal to explore the system helped performance when compared to a specific goal to reach certain values when participants were given a good model, but not when given a poor model that suggested the wrong hypothesis space. Our findings support the three-space theory. They emphasize the importance of understanding for problem solving and stress the need to study underlying processes.
Die optimale Dimensionierung von IT-Hardware stellt Entscheider aufgrund der stetigen Weiterentwicklung zunehmend vor Herausforderungen. Dies gilt im Speziellen auch für Analytics-Infrastrukturen, die zunehmend auch neue Software zur Analyse von Daten einsetzen, welche in den Ressourcenanforderungen stark variieren. Damit eine flexible und gleichzeitig effiziente Gestaltung von Analytics-Infrastrukturen erreicht werden kann, wird ein dynamisch arbeitendes Architekturkonzept vorgeschlagen, das Aufgaben auf Basis einer systemspezifischen Entscheidungsmaxime mit Hilfe einer Eskalationsmatrix verteilt und hierfür Aufgabencharakteristiken sowie verfügbare Hardwareausstattungen entsprechend ihrer Auslastung berücksichtigt.
Recent studies of short-term serial order memory have suggested that the maintenance of order information does not involve domain-specific processes. We carried out two dual task experiments aimed at resolving several ambiguities in those studies. In our experiments, encoding and response of one serial reconstruction task was embedded within encoding and response of a concurrent serial reconstruction task. Order demands in both tasks were independently varied so as to find revealing patterns of interference between the two tasks. In Experiment 1, participants were to maintain and reconstruct the order of a list of verbal materials, while maintaining a list of spatial materials or vice-versa. Increasing the order demands in the outer reconstruction task resulted in small or non reliable performance decrements in the embedded reconstruction task. Experiment 2 sought to compare these results against two same-domain baseline conditions (two verbal lists or two spatial lists). In all conditions, increasing order demands in the outer task resulted in small or non-reliable performance decrements in the embedded task. However, performance in the embedded tasks was generally lower in the same-domain baseline conditions than in the cross-domain conditions. We argue that the main effect of domain in Experiment 2 indicates the contribution of domain-specific processes to short-term serial order maintenance. In addition, we interpret the failure to find consistent cross-list interference irrespective of domain as indicating the involvement of grouping mechanisms in concurrently performed serial order tasks. (C) 2015 Elsevier Inc. All rights reserved.
In a series of experiments, we tested a recently proposed hypothesis stating that the degree of alignment between the form of a mental representation resulting from learning with a particular visualization format and the specific requirements of a learning task determines learning performance (task-appropriateness). Groups of participants were required to learn the stroke configuration, the stroke order, or the stroke directions of a set of Chinese pseudocharacters. For each learning task, participants were divided into groups receiving dynamic, static-sequential, or static visualizations. An old/new character recognition task was given at test. The results showed that learning both stroke configuration and stroke order was best with static pictures (Experiments 1 and 2), while there was no reliable difference between the groups for learning stroke direction (Experiment 3). An additional experiment, however, revealed that learning with sequential pictures was superior when testing was carried out with sequential pictures, irrespective of the learning task (Experiment 4). The combined evidence from all experiments speaks against task requirements playing a role in determining the effectiveness of a visualization format. Furthermore, the evidence supports the view that a high degree of congruence between information presented during learning and information presented at test results in better learning (study-test congruence). Implications for instructional design are discussed.
Mobile Applikationen eignen sich als strukturelle Unterstützungsangebote für Studierende während des Studieneinstiegs. Durch die App Reflect.UP werden Studienorganisation, Studieninhalte und -ziele von Studierenden reflektiert. Der bewusste Umgang mit dem studentischen Kompetenzerwerb als wissenschaftliche eflexionskompetenz ist immanenter Bestandteil der akademischen Professionalisierung und steht in diesem Beitrag im Vordergrund. Gezeigt wird, wie aus Studienordnungen und Modulbeschreibungen systematisch Fragen zur studentischen Reflexion herausgearbeitet werden und dadurch ein Kompetenzraster entsteht. Die durch den praktischen Einsatz von Reflect.UP gewonnenen Daten werden ausgewertet und dahingehend diskutiert, welche Rückschlüsse sich hieraus auf die Problemlagen und Lernprozesse der Studierenden sowie für die Studiengangsorganisation(en) ziehen lassen. Darüber hinaus werden die Stärken und Schwächen einer mobilen Applikation als sozial- und informationswissenschaftliches Amalgam zur strukturellen Unterstützung der Studieneingangsphase reflektiert.
Let A be a nonlinear differential operator on an open set X subset of R-n and S a closed subset of X. Given a class F of functions in X, the set S is said to be removable for F relative to A if any weak solution of A(u) = 0 in XS of class F satisfies this equation weakly in all of X. For the most extensively studied classes F, we show conditions on S which guarantee that S is removable for F relative to A.
The current study investigates an interaction between numbers and physical size (i.e. size congruity) in visual search. In three experiments, participants had to detect a physically large (or small) target item among physically small (or large) distractors in a search task comprising single-digit numbers. The relative numerical size of the digits was varied, such that the target item was either among the numerically large or small numbers in the search display and the relation between numerical and physical size was either congruent or incongruent. Perceptual differences of the stimuli were controlled by a condition in which participants had to search for a differently coloured target item with the same physical size and by the usage of LCD-style numbers that were matched in visual similarity by shape transformations. The results of all three experiments consistently revealed that detecting a physically large target item is significantly faster when the numerical size of the target item is large as well (congruent), compared to when it is small (incongruent). This novel finding of a size congruity effect in visual search demonstrates an interaction between numerical and physical size in an experimental setting beyond typically used binary comparison tasks, and provides important new evidence for the notion of shared cognitive codes for numbers and sensorimotor magnitudes. Theoretical consequences for recent models on attention, magnitude representation and their interactions are discussed.
We show that self-consistent partial synchrony in globally coupled oscillatory ensembles is a general phenomenon. We analyze in detail appearance and stability properties of this state in possibly the simplest setup of a biharmonic Kuramoto-Daido phase model as well as demonstrate the effect in limit-cycle relaxational Rayleigh oscillators. Such a regime extends the notion of splay state from a uniform distribution of phases to an oscillating one. Suitable collective observables such as the Kuramoto order parameter allow detecting the presence of an inhomogeneous distribution. The characteristic and most peculiar property of self-consistent partial synchrony is the difference between the frequency of single units and that of the macroscopic field.
Conclusion
(2016)
This chapter revisits the role of the new modes of governance in areas of limited statehood. First, it states that there is no linear relationship between degrees of statehood and the overall effectiveness of new modes of sustainability governance. Second, the chapter states that, in most of the cases, national governments are hesitant or even actively hamper the development of new modes of governance. Third, it shows that the absence of the shadow of hierarchy can indeed lead to ineffective new modes of governance. However, the shadow of hierarchy does not necessarily need to be cast by states. Finally, the author reviews the complexities involved in participatory practices, stressing the importance of institutional structures and knowledgeable brokers. The chapter concludes by outlining fields for future research.
Introduction
(2016)
The Paris Agreement for Climate Change or the Sustainable Development Goals (SDGs) rely on new modes of governance for implementation. Indeed, new modes of governance such as market-based instruments, public-private partnerships or multi-stakeholder initiatives have been praised for playing a pivotal role in effective and legitimate sustainability governance. Yet, do they also deliver in areas of limited statehood? States such as Malaysia or the Dominican Republic partly lack the ability to implement and enforce rules; their statehood is limited. This introduction provides the analytical framework of this volume and critically examines the performance of new modes of governance in areas of limited statehood, drawing on the book’s in-depth case studies on issues of climate change, biodiversity, and health.
This chapter investigates the trajectory of establishing the Forest Stewardship Council (FSC) in the early 1990s as the first private transnational certification organization with an antagonistic stakeholder body. Its main contribution is a micro-analysis of the founding assembly in 1993. By investigating the role of brokers within the negotiation as one institutional scope condition for ‘arguing’ having occurred, the chapter adopts a dramaturgical approach. It contends that the authority of brokers is not necessarily institutionally given, but needs to be gained: brokers have to prove situationally that their knowledge is relevant and that they are speaking impartially in the interest of progress rather than their own. The chapter stresses the importance of procedural knowledge which brokers provide in contrast to policy knowledge.
In cancer patients, pain is one of the main symptoms and especially in the late stages of disease, these symptoms can be associated with considerable suffering. In psycho-oncology, preliminary psychological therapies targeting cancer pain have been tested; however, a systematic review of available interventions is lacking, especially considering their dissemination, evidence base, study quality, and the comparison with established treatments. Therefore, the aim of the current study is to systematically review the current research on psychological treatments for pain in cancer patients. During May 2014, MEDLINE, PsycINFO, PSYNDEX, and CENTRAL databases were searched. Psychological treatments for pain in adult cancer patients studied in randomized, controlled trials (RCTs) and referring to pain as primary or secondary outcome were included. After examination for inclusion, structured data extraction and assessment followed. Data were synthesized narratively. In the review, 32 RCTs were included. Studies mainly referred to patients with breast cancer or patients in earlier stages of the disease. The methodological quality of included studies was heterogeneous. Most commonly, short interventions were delivered by nurses in out-patient settings. Interventions including education and relaxation techniques were utilized most often, followed by interventions with behavioral or cognitive components. A need for research persists regarding efficacy of current psychotherapeutic interventions, or the role of mediator variables (e. g., coping) on pain perception in cancer patients. Studies with high methodological quality which comprehensively and transparently report on interventions and designs are lacking.
Die Danziger Verwaltungspraxis des frühen 19. Jahrhunderts im Nexus von Reform, Restauration, Emanzipation und antijüdischen Vorurteilen.
Michał Szulc analysiert die Umsetzung der staatlichen Judenpolitik in der preußischen Provinz am Beispiel Danzigs. Dabei zeigt er die Emanzipation der Juden als Kampfplatz von Interessengruppen und individuellen Akteuren. Der Autor untersucht sowohl die Diskussionen vor Ort als auch in machtpolitischen Zentren wie Berlin und Paris.
Deutlich wird dabei die Diskrepanz zwischen gesetzlicher Norm und Alltagspraxis, zwischen politischem Programm und dessen tatsächlicher Wirkung. In diesem politisch-rechtlichen Prozess setzten sich Staat und Stadt konfrontativ über die Lage der Juden in Danzig auseinander. Akteure wie Napoleon I., König Friedrich Wilhelm III. oder Staatskanzler Karl August von Hardenberg versuchten mit unterschiedlichem Erfolg das Ausmaß der Emanzipation ebenso so zu prägen, wie es 'einfache Leute', etwa der Rabbinatskandidat Bram oder der Stadtverordnete Zernecke, taten. Die Rollen der Protagonisten waren dabei variabel: Einige Staatsbeamte vertraten die Position der Stadt, manche Bürger die des Staates. Zudem entwickelte sich im Laufe der Debatte jenseits rechtlicher Normen eine lokale Praxis, die Juden mehr Raum in der Gesellschaft gewährte.
The determination of the total carbon storage of peatlands is of high relevance in the context of climate-change mitigation efforts. This determination relies on data about stratigraphy and peat properties, which are conventionally collected by coring. Ground-penetrating radar (GPR) and electrical resistivity imaging (ERI) can support these point data by providing subsoil information in two-dimensional cross-sections. In this study, GPR and ERI were conducted at two groundwater-fed fen sites located in the temperate zone in north-east Germany. The fens of this region are embedded in low conductive glacial sand and are characterised by thick layers of gyttja, which can be either mineral or organic. The two study sites are representative of this region with respect to stratigraphy (total thickness, peat and gyttja types) and ecological conditions (pH-value, trophic condition). The aim of this study is to assess the suitability of GPR and ERI to detect stratigraphy and peat properties under these characteristic site conditions. Results show that GPR clearly detects the interfaces between (i) Carex and brown-moss peat, (ii) brown-moss peat and organic gyttja, (iii) organic- and mineral gyttja, and (iv) mineral gyttja and the parent material (glacial sand). These layers differ in bulk density and the related organic matter content. ERI, however, does not delineate these layers; rather it delineates regions of varying properties. At our base-rich site, pore fluid conductivity and cation.exchange capacity are the main factors that determine peat electrical conductivity (reverse of resistivity), whereas organic matter and water content are most influential at the more acidic site. Thus the correlation between peat properties and electrical conductivity are driven by site-specific conditions, which are mainly determined by the solute load in the groundwater at fens. When the total organic deposits exceed a thickness of 5 m, the depth of investigation by GPR is limited due to increasing attenuation. This is not a limiting factor for ERI, where the transition from organic deposits to glacial sand is visible at both sites. Due to these specific sensitivities, a combined application of GPR and ERI meets the demand for up-to-date information on carbon storage of peatlands, which is, moreover, very site-specific because of the inherent variety of ecological conditions and stratigraphy between peatlands in general and between fens and bogs in particular. (C) 2016 Elsevier B.V. All rights reserved.
Mycobacterium tuberculosis (M. tuberculosis) is the intracellular bacterium responsible for tuberculosis disease (TD). Inside the phagosomes of activated macrophages, M. tuberculosis is exposed to cytotoxic hydroperoxides such as hydrogen peroxide, fatty acid hydroperoxides and peroxynitrite. Thus, the characterization of the bacterial antioxidant systems could facilitate novel drug developments. In this work, we characterized the product of the gene Rv1608c from M. tuberculosis, which according to sequence homology had been annotated as a putative peroxiredoxin of the peroxiredoxin Q subfamily (PrxQ B from M. tuberculosis or MtPrxQ B). The protein has been reported to be essential for M. tuberculosis growth in cholesterol-rich medium. We demonstrated the M. tuberculosis thioredoxin B/C-dependent peroxidase activity of MtPrxQ B, which acted as a two-cysteine peroxiredoxin that could function, although less efficiently, using a one-cysteine mechanism. Through steady-state and competition kinetic analysis, we proved that the net forward rate constant of MtPrxQ B reaction was 3 orders of magnitude faster for fatty acid hydroperoxides than for hydrogen peroxide (3x10(6) vs 6x10(3) M-1 s(-1), respectively), while the rate constant of peroxynitrite reduction was (0.6-1.4) x10(6) M-1 s(-1) at pH 7.4. The enzyme lacked activity towards cholesterol hydroperoxides solubilized in sodium deoxycholate. Both thioredoxin B and C rapidly reduced the oxidized form of MtPrxQ B, with rates constants of 0.5x10(6) and 1x10(6) M-1 s(-1), respectively. Our data indicated that MtPrxQ B is monomeric in solution both under reduced and oxidized states. In spite of the similar hydrodynamic behavior the reduced and oxidized forms of the protein showed important structural differences that were reflected in the protein circular dichroism spectra.
Reconstructing and understanding the Human Physiome virtually is a complex mathematical problem, and a highly demanding computational challenge. Mathematical models spanning from the molecular level through to whole populations of individuals must be integrated, then personalized. This requires interoperability with multiple disparate and geographically separated data sources, and myriad computational software tools. Extracting and producing knowledge from such sources, even when the databases and software are readily available, is a challenging task. Despite the difficulties, researchers must frequently perform these tasks so that available knowledge can be continually integrated into the common framework required to realize the Human Physiome. Software and infrastructures that support the communities that generate these, together with their underlying standards to format, describe and interlink the corresponding data and computer models, are pivotal to the Human Physiome being realized. They provide the foundations for integrating, exchanging and re-using data and models efficiently, and correctly, while also supporting the dissemination of growing knowledge in these forms. In this paper, we explore the standards, software tooling, repositories and infrastructures that support this work, and detail what makes them vital to realizing the Human Physiome.
In den 2000er-Jahren stiegen die Rohstoffpreise enorm an. Auslöser waren die wirtschaftliche Entwicklung der Schwellenländer, allen voran Chinas, sowie der gestiegene Rohstoffbedarf durch technologische Innovationen. Diese „Rohstoffkrise“ veränderte das Verhältnis der Rohstoff exportierenden und importierenden Staaten zueinander. Auch wird Rohstoffpolitik nicht mehr nur unter wirtschaftlichen, sondern ebenso unter ökologischen und sozialen Kriterien betrachtet. Der Beitrag erläutert die Ursachen und benennt Auswirkungen der Krise.
This dissertation examines the impact of the type of referring expression on the acquisition of word order variation in German-speaking preschoolers. A puzzle in the area of language acquisition concerns the production-comprehension asymmetry for non-canonical sentences like "Den Affen fängt die Kuh." (“The monkey, the cow chases.”), that is, preschoolers usually have difficulties in accurately understanding non-canonical sentences approximately until age six (e.g., Dittmar et al., 2008) although they produce non-canonical sentences already around age three (e.g., Poeppel & Wexler, 1993; Weissenborn, 1990). This dissertation investigated the production and comprehension of non-canonical sentences to address this issue.
Three corpus analyses were conducted to investigate the impact of givenness, topic status and the type of referring expression on word order in the spontaneous speech of two- to four-year-olds and the child-directed speech produced by their mothers. The positioning of the direct object in ditransitive sentences was examined; in particular, sentences in which the direct object occurred before or after the indirect object in the sentence-medial positions and sentences in which it occurred in the sentence-initial position. The results reveal similar ordering patterns for children and adults. Word order variation was to a large extent predictable from the type of referring expression, especially with respect to the word order involving the sentence-medial positions. Information structure (e.g., topic status) had an additional impact only on word order variation that involved the sentence-initial position.
Two comprehension experiments were conducted to investigate whether the type of referring expression and topic status influences the comprehension of non-canonical transitive sentences in four- and five-year-olds. In the first experiment, the topic status of the one of the sentential arguments was established via a preceding context sentence, and in the second experiment, the type of referring expression for the sentential arguments was additionally manipulated by using either a full lexical noun phrase (NP) or a personal pronoun. The results demonstrate that children’s comprehension of non-canonical sentences improved when the topic argument was realized as a personal pronoun and this improvement was independent of the grammatical role of the arguments. However, children’s comprehension was not improved when the topic argument was realized as a lexical NP.
In sum, the results of both production and comprehension studies support the view that referring expressions may be seen as a sentence-level cue to word order and to the information status of the sentential arguments. The results highlight the important role of the type of referring expression on the acquisition of word order variation and indicate that the production-comprehension asymmetry is reduced when the type of referring expression is considered.
A convenient synthesis of gamma-spirolactams in only two steps was developed. Birch reduction of benzoic acids and immediate alkylation with chloroacetonitrile afforded cyclohexadienes in high yields. The products could be isolated by crystallization on a large scale in analytically pure form. Subsequent hydrogenation with platinum(IV) oxide as the catalyst reduced the nitrile functionality and the double bonds in the same step with excellent stereoselectivity. The relative configurations were determined unequivocally by X-ray analyses. Direct cyclization of the intermediary formed amino acids afforded the desired gamma-spirolactams in excellent overall yields. The procedure is characterized by few steps, cheap reagents, and can be performed on a large scale, interesting for industrial processes.
Scripts that store knowledge of everyday events are fundamentally important for managing daily routines. Content event knowledge (i.e., knowledge about which events belong to a script) and temporal event knowledge (i.e., knowledge about the chronological order of events in a script) constitute qualitatively different forms of knowledge. However, there is limited information about each distinct process and the time course involved in accessing content and temporal event knowledge. Therefore, we analyzed event-related potentials (ERPs) in response to either correctly presented event sequences or event sequences that contained a content or temporal error. We found an N400, which was followed by a posteriorly distributed P600 in response to content errors in event sequences. By contrast, we did not find an N400 but an anteriorly distributed P600 in response to temporal errors in event sequences. Thus, the N400 seems to be elicited as a response to a general mismatch between an event and the established event model. We assume that the expectancy violation of content event knowledge, as indicated by the N400, induces the collapse of the established event model, a process indicated by the posterior P600. The expectancy violation of temporal event knowledge is assumed to induce an attempt to reorganize the event model in working memory, a process indicated by the frontal P600. (C) 2015 Elsevier Ltd. All rights reserved.
1. Plant-plant interactions may critically modify the impact of climate change on plant communities. However, the magnitude and even direction of potential future interactions remains highly debated, especially for water-limited ecosystems. Predictions range from increasing facilitation to increasing competition with future aridification. 2. The different methodologies used for assessing plant-plant interactions under changing environmental conditions may affect the outcome but they are not equally represented in the literature. Mechanistic experimental manipulations are rare compared with correlative approaches that infer future patterns from current observations along spatial climatic gradients. 3. Here, we utilize a unique climatic gradient in combination with a large-scale, long-term experiment to test whether predictions about plant-plant interactions yield similar results when using experimental manipulations, spatial gradients or temporal variation. We assessed shrub-annual interactions in three different sites along a natural rainfall gradient (spatial) during 9 years of varying rainfall (temporal) and 8 years of dry and wet manipulations of ambient rainfall (experimental) that closely mimicked regional climate scenarios. 4. The results were fundamentally different among all three approaches. Experimental water manipulations hardly altered shrub effects on annual plant communities for the assessed fitness parameters biomass and survival. Along the spatial gradient, shrub effects shifted from clearly negative to mildly facilitative towards drier sites, whereas temporal variation showed the opposite trend: more negative shrub effects in drier years. 5. Based on our experimental approach, we conclude that shrub-annual interaction will remain similar under climate change. In contrast, the commonly applied space-for-time approach based on spatial gradients would have suggested increasing facilitative effects with climate change. We discuss potential mechanisms governing the differences among the three approaches. 6. Our study highlights the critical importance of long-term experimental manipulations for evaluating climate change impacts. Correlative approaches, for example along spatial or temporal gradients, may be misleading and overestimate the response of plant-plant interactions to climate change.
Defining species by their climatic niche is the simple and intuitive principle underlying Bioclimatic Envelope Model (BEM) predictions for climate change effects. However, these correlative models are often criticised for neglecting many ecological processes. Here, we apply the same niche principle to entire communities within a medium/long-term climate manipulation study, where ecological processes are inherently included. In a nine generation study in Israel, we manipulated rainfall (Drought -30%; Irrigation +30%; Control natural rainfall) at two sites which differ chiefly in rainfall quantity and variability. We analysed community responses to the manipulations by grouping species based on their climatic rainfall niche. These responses were compared to analyses based on single species, total densities, and commonly used taxonomic groupings. Climate Niche Groups yielded clear and consistent results: within communities, those species distributed in drier regions performed relatively better in the drought treatment, and those from wetter climates performed better when irrigated. In contrast, analyses based on other principles revealed little insight into community dynamics. Notably, most relationships were weaker at the drier, more variable site, suggesting that enhanced adaptation to variability may buffer climate change impacts. We provide robust experimental evidence that using climatic niches commonly applied in BEMs is a valid approach for eliciting community changes in response to climate change. However, we also argue that additional empirical information needs to be gathered using experiments in situ to correctly assess community vulnerability. Climatic Niche Groups used in this way, may therefore provide a powerful tool and directional testing framework to generalise and compare climate change impacts across habitats. (C) 2016 The Authors. Published by Elsevier GmbH.
Context. For the spectral analysis of high-resolution and high signal-to-noise (S/N) spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that is used for their calculation. Aims. New Kr IV-VII oscillator strengths for a large number of lines enable us to construct more detailed model atoms for our NLTE model-atmosphere calculations. This enables us to search for additional Kr lines in observed spectra and to improve Kr abundance determinations. Methods. We calculated Kr IV-VII oscillator strengths to consider radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models for the analysis of Kr lines that are exhibited in high-resolution and high S/N ultraviolet (UV) observations of the hot white dwarf RE 0503-289. Results. We reanalyzed the effective temperature and surface gravity and determined T-eff = 70 000 +/- 2000 K and log (g/cm s(-2)) = 7.5 +/- 0.1. We newly identified ten Kr V lines and one Kr vi line in the spectrum of RE 0503-289. We measured a Kr abundance of 3.3 +/- 0.3 (logarithmic mass fraction). We discovered that the interstellar absorption toward RE 0503-289 has a multi-velocity structure within a radial-velocity interval of -40 km s(-1) < upsilon(rad) < +18 km s(-1). Conclusions. Reliable measurements and calculations of atomic data are a prerequisite for state-of-the-art NLTE stellar-atmosphere modeling. Observed Kr V-VII line profiles in the UV spectrum of the white dwarf RE 0503-289 were simultaneously well reproduced with our newly calculated oscillator strengths.
Zum Hundertsten nichts Neues
(2016)
Optical biosensors based on porous silicon were fabricated by metal assisted chemical etching. Thereby double layered porous silicon structures were obtained consisting of porous pillars with large pores on top of a porous silicon layer with smaller pores. These structures showed a similar sensing performance in comparison to electrochemically produced porous silicon interferometric sensors.
This article explores a recent performance of excerpts from T.S. Eliot’s Four Quartets (1935/36–1942) entitled Engaging Eliot: Four Quartets in Word, Color, and Sound as an example of live poetry. In this context, Eliot’s poem can be analysed as an auditory artefact that interacts strongly with other oral performances (welcome addresses and artists’ conversations), as well as with the musical performance of Christopher Theofanidis’s quintet “At the Still Point” at the end of the opening of Engaging Eliot. The event served as an introduction to a 13-day art exhibition and engaged in a re-evaluation of Eliot’s poem after 9/11: while its first part emphasises the connection between Eliot’s poem and Christian doctrine, its second part – especially the combination of poetry reading and musical performance – highlights the philosophical and spiritual dimensions of Four Quartets.
TripleA is a workshop series founded by linguists from the University of Tübingen and the University of Potsdam. Its aim is to provide a forum for semanticists doing fieldwork on understudied languages, and its focus is on languages from Africa, Asia, Australia and Oceania. The second TripleA workshop was held at the University of Potsdam, June 3-5, 2015.
Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clones, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity.
The population structure of the highly mobile marine mammal, the harbor porpoise (Phocoena phocoena), in the Atlantic shelf waters follows a pattern of significant isolation-by-distance. The population structure of harbor porpoises from the Baltic Sea, which is connected with the North Sea through a series of basins separated by shallow underwater ridges, however, is more complex. Here, we investigated the population differentiation of harbor porpoises in European Seas with a special focus on the Baltic Sea and adjacent waters, using a population genomics approach. We used 2872 single nucleotide polymor-phisms (SNPs), derived from double digest restriction-site associated DNA sequencing (ddRAD-seq), as well as 13 microsatellite loci and mitochondrial haplotypes for the same set of individuals. Spatial principal components analysis (sPCA), and Bayesian clustering on a subset of SNPs suggest three main groupings at the level of all studied regions: the Black Sea, the North Atlantic, and the Baltic Sea. Furthermore, we observed a distinct separation of the North Sea harbor porpoises from the Baltic Sea populations, and identified splits between porpoise populations within the Baltic Sea. We observed a notable distinction between the Belt Sea and the Inner Baltic Sea sub-regions. Improved delineation of harbor porpoise population assignments for the Baltic based on genomic evidence is important for conservation management of this endangered cetacean in threatened habitats, particularly in the Baltic Sea proper. In addition, we show that SNPs outperform microsatellite markers and demonstrate the utility of RAD-tags from a relatively small, opportunistically sampled cetacean sample set for population diversity and divergence analysis.
The all-female Amazon molly (Poecilia formosa) originated from a single hybridization of two bisexual ancestors, Atlantic molly (Poecilia mexicana) and sailfin molly (Poecilia latipinna). As a gynogenetic species, the Amazon molly needs to copulate with a heterospecific male, but the genetic information of the sperm-donor does not contribute to the next generation, as the sperm only acts as the trigger for the diploid eggs’ embryogenesis. Here, we study the sequence evolution and gene expression of the duplicated genes coding for androgen receptors (ars) and other pathway-related genes, i.e., the estrogen receptors (ers) and cytochrome P450, family19, subfamily A, aromatase genes (cyp19as), in the Amazon molly, in comparison to its bisexual ancestors. Mollies possess–as most other teleost fish—two copies of the ar, er, and cyp19a genes, i.e., arα/arβ, erα/erβ1, and cyp19a1 (also referred as cyp19a1a)/cyp19a2 (also referred to as cyp19a1b), respectively. Non-synonymous single nucleotide polymorphisms (SNPs) among the ancestral bisexual species were generally predicted not to alter protein function. Some derived substitutions in the P. mexicana and one in P. formosa are predicted to impact protein function. We also describe the gene expression pattern of the ars and pathway-related genes in various tissues (i.e., brain, gill, and ovary) and provide SNP markers for allele specific expression research. As a general tendency, the levels of gene expression were lowest in gill and highest in ovarian tissues, while expression levels in the brain were intermediate in most cases. Expression levels in P. formosa were conserved where expression did not differ between the two bisexual ancestors. In those cases where gene expression levels significantly differed between the bisexual species, P. formosa expression was always comparable to the higher expression level among the two ancestors. Interestingly, erβ1 was expressed neither in brain nor in gill in the analyzed three molly species, which implies a more important role of erα in the estradiol synthesis pathway in these tissues. Furthermore, our data suggest that interactions of steroid-signaling pathway genes differ across tissues, in particular the interactions of ars and cyp19as.
Hemidiaptomus diaptomid copepods are known to be excellent biological indicators for the highly biodiverse crustacean communities inhabiting Mediterranean temporary ponds (MTPs), an endangered inland water habitat whose conservation is considered a priority according to the "Habitat Directive" of the European Union. This study reports on the characterization of five polymorphic microsatellite loci in Hemidiaptomus gurneyi, to be used as markers for fine-scale studies on the population genetic structure and metapopulation dynamics of a typical and obligate MTP dweller. The five selected loci proved to be polymorphic in the species, with three to five polymorphic loci per studied population. Overall, mean heterozygosity scored for all loci and populations was lower than that reported for the few other diaptomid species for which microsatellite loci have been to date described; this is possibly due to the intrinsically fragmented and isolated peculiar habitat inhabited by the species. Furthermore, the presence of indels within the flanking regions of selected loci was scored. This study, albeit confirming the technical difficulties in finding proper microsatellite markers in copepods, provides for the first time a set of useful polymorphic microsatellite loci for a Hemidiaptomus species, thus allowing the realization of fine-scale phylogeographic and population genetics studies of this flagship crustacean taxon for MTPs.
The population structure of the highly mobile marine mammal, the harbor porpoise (Phocoena phocoena), in the Atlantic shelf waters follows a pattern of significant isolation-by-distance. The population structure of harbor porpoises from the Baltic Sea, which is connected with the North Sea through a series of basins separated by shallow underwater ridges, however, is more complex. Here, we investigated the population differentiation of harbor porpoises in European Seas with a special focus on the Baltic Sea and adjacent waters, using a population genomics approach. We used 2872 single nucleotide polymorphisms (SNPs), derived from double digest restriction-site associated DNA sequencing (ddRAD-seq), as well as 13 microsatellite loci and mitochondrial haplotypes for the same set of individuals. Spatial principal components analysis (sPCA), and Bayesian clustering on a subset of SNPs suggest three main groupings at the level of all studied regions: the Black Sea, the North Atlantic, and the Baltic Sea. Furthermore, we observed a distinct separation of the North Sea harbor porpoises from the Baltic Sea populations, and identified splits between porpoise populations within the Baltic Sea. We observed a notable distinction between the Belt Sea and the Inner Baltic Sea sub-regions. Improved delineation of harbor porpoise population assignments for the Baltic based on genomic evidence is important for conservation management of this endangered cetacean in threatened habitats, particularly in the Baltic Sea proper. In addition, we show that SNPs outperform microsatellite markers and demonstrate the utility of RAD-tags from a relatively small, opportunistically sampled cetacean sample set for population diversity and divergence analysis.
The all-female Amazon molly (Poecilia formosa) originated from a single hybridization of two bisexual ancestors, Atlantic molly (Poecilia mexicana) and sailfin molly (Poecilia latipinna). As a gynogenetic species, the Amazon molly needs to copulate with a heterospecific male, but the genetic information of the sperm-donor does not contribute to the next generation, as the sperm only acts as the trigger for the diploid eggs’ embryogenesis. Here, we study the sequence evolution and gene expression of the duplicated genes coding for androgen receptors (ars) and other pathway-related genes, i.e., the estrogen receptors (ers) and cytochrome P450, family19, subfamily A, aromatase genes (cyp19as), in the Amazon molly, in comparison to its bisexual ancestors. Mollies possess–as most other teleost fish—two copies of the ar, er, and cyp19a genes, i.e., arα/arβ, erα/erβ1, and cyp19a1 (also referred as cyp19a1a)/cyp19a2 (also referred to as cyp19a1b), respectively. Non-synonymous single nucleotide polymorphisms (SNPs) among the ancestral bisexual species were generally predicted not to alter protein function. Some derived substitutions in the P. mexicana and one in P. formosa are predicted to impact protein function. We also describe the gene expression pattern of the ars and pathway-related genes in various tissues (i.e., brain, gill, and ovary) and provide SNP markers for allele specific expression research. As a general tendency, the levels of gene expression were lowest in gill and highest in ovarian tissues, while expression levels in the brain were intermediate in most cases. Expression levels in P. formosa were conserved where expression did not differ between the two bisexual ancestors. In those cases where gene expression levels significantly differed between the bisexual species, P. formosa expression was always comparable to the higher expression level among the two ancestors. Interestingly, erβ1 was expressed neither in brain nor in gill in the analyzed three molly species, which implies a more important role of erα in the estradiol synthesis pathway in these tissues. Furthermore, our data suggest that interactions of steroid-signaling pathway genes differ across tissues, in particular the interactions of ars and cyp19as.
Using data from the Berlin Speed Dating Study, we tested rival hypotheses concerning the effects of self-enhancement of attractiveness on dating outcomes. Three hundred eighty-two participants took part in one of the 17 speed-dating sessions. After each speed-dating interaction, participants indicated how interesting they found the respective person as a long-term and short-term partner. Using social relations analyses, we computed perceiver effects (being more or less choosy) and target effects (being rated as more or less interesting) of long-term and short-term partner ratings. Self-enhancement was operationalized as the discrepancy between self-rated attractiveness and four components of actual attractiveness (observer-rated facial and vocal attractiveness, height and body mass index). Results indicated that self-enhancers were less choosy with respect to their interest for short-term partners, which was especially true for men, but more choosy with respect to long-term partners. With regard to popularity as a mate, potential partners indicated that they found self-enhancers more interesting as short-term partners but not as long-term partners. As self-enhancement is a key component of narcissism, these results are consistent with findings that narcissists perceive many sexual affairs as an achievement, while preferring selected ‘trophy’ long-term partners, and narcissists have a charming appeal for short-term, but not lasting, social relationships.
Z,E-Diene sind ein häufig auftretendes Strukturmerkmal in Naturstoffen. Aus diesem Grund ist die einfache Darstellung dieser Struktureinheit von großen Interesse in der organischen Chemie.
Das erste Ziel der vorliegenden Arbeit war daher die Weiterentwicklung der Ringschlussmetathese-/ baseninduzierten Ringöffnungs-/ Veresterungssequenz (RBRV-Sequenz) zur Synthese von (2Z,4E)-Diencarbonsäureethylestern ausgehend von Butenoaten. Dazu wurde zunächst die RBRV-Sequenz optimiert. Diese aus drei Schritten bestehende Sequenz konnte in einem Eintopf-Verfahren angewendet werden. Die Ringschlussmetathese gelang mit einer Katalysatorbeladung von 1 mol% des GRUBBS-Katalysators der zweiten Generation in Dichlormethan. Für die baseninduzierte Ringöffnung des β,γ-ungesättigten δ Valerolactons wurde NaHMDS verwendet. Die Alkylierung der Carboxylatspezies gelang mit dem MEERWEIN-Reagenz. Die Anwendbarkeit der Sequenz wurde für verschiedene Substrate demonstriert.
Die Erweiterung der Methode auf α-substituierte Butenoate unterlag starken Einschränkungen. So konnte der Zugang für α Hydroxyderivate realisiert werden. Bei der Anwendung der RBRV-Sequenz auf die α-substituierten Butenoate wurde festgestellt, dass diese sich nur in moderaten Ausbeuten umsetzen ließen und zudem nicht selektiv zu den (2E,4E)-konfigurierten α-substituierten-Dienestern reagierten.
Der Einsatz von Eninen unter den Standardbedingungen der RBRV-Sequenz gelang nicht. Erst nach Modifizierung der Sequenz (höhere Katalysatorbeladung, Wechsel des Lösungsmittels) konnten die [3]Dendralen-Produkte in geringen Ausbeuten erhalten werden.
Im zweiten Teil der Arbeit wurde der Einsatz von (2Z,4E)-Diencarbonsäureethylestern in der Totalsynthese von Naturstoffen untersucht. Dazu wurden zunächst die Transformationsmöglichkeiten der Ester geprüft. Es konnte gezeigt werden, dass sich (2Z,4E)-Diencarbonsäureethylester insbesondere zur Synthese von (2Z,4E)-Aldehyden sowie zum Aufbau der (3Z,5E)-Dien-1-in-Struktur eignen.
Anhand dieser Ergebnisse wurde im Anschluss die RBRV-Sequenz in der Totalsynthese eingesetzt. Dazu wurde zunächst der (2Z,4E)-Dienester Microsphaerodiolin in seiner ersten Totalsynthese auf drei verschiedene Routen hergestellt. Im Anschluss wurden sechs verschiedene Polyacetylene mit einer (3Z,5E)-Dien-1-in-Einheit hergestellt. Schlüsselschritte in ihrer Synthese waren immer die RBRV-Sequenz zum Aufbau der Z,E-Dien-Einheit, die Transformation des Esters in ein terminales Alkin sowie die CADIOT-CHODKIEWICZ-Kupplung zum Aufbau unsymmetrischer Polyine. Alle sechs Polyacetylene wurden zum ersten Mal in einer Totalsynthese synthetisiert. Drei Polyacetylene wurden ausgehend von (S)-Butantriol enantiomerenrein dargestellt. Anhand ihrer Drehwerte konnte eine Revision der von YAO und Mitarbeitern vorgenommen Zuordnung der Absolutkonfiguration der Naturstoffe vorgenommen werden.
Der Bittergeschmack warnt den Organismus vor potentiell verdorbener oder giftiger Nahrung und ist somit ein wichtiger Kontrollmechanismus. Die initiale Detektion der zahlreich vorkommenden Bitterstoffe erfolgt bei der Maus durch 35 Bitterrezeptoren (Tas2rs), die sich im Zungengewebe befinden. Die Geschmacksinformation wird anschließend von der Zunge über das periphere (PNS) ins zentrale Nervensystem (ZNS) geleitet, wo deren Verarbeitung stattfindet. Die Verarbeitung der Geschmacksinformation konnte bislang nicht gänzlich aufgeklärt werden. Neue Studien deuten auf eine Expression von Tas2rs auch im PNS und ZNS entlang der Geschmacksbahn hin. Über Vorkommen und Aufgaben dieser Rezeptoren bzw. Rezeptorzellen im Nervensystem ist bislang wenig bekannt.
Im Rahmen dieser Arbeit wurde die Tas2r-Expression in verschiedenen Mausmodellen untersucht, Tas2r-exprimierende Zellen identifiziert und deren Funktionen bei der Übertragung der Geschmacksinformationen analysiert. Im Zuge der Expressionsanalysen mittels qRT-PCR konnte die Expression von 25 der 35 bekannten Bittergeschmacksrezeptoren im zentralen Nervensystem der Maus nachgewiesen werden. Die Expressionsmuster im PNS sowie im ZNS lassen darüber hinaus Vermutungen zu Funktionen in verschiedenen Bereichen des Nervensystems zu. Basierend auf den Ergebnissen der Expressionsanalysen war es möglich, stark exprimierte Tas2rs mittels In-situ-Hybridisierung in verschiedenen Zelltypen zu visualisieren. Des Weiteren konnten immunhistochemische Färbungen unter Verwendung eines genetisch modifizierten Mausmodells die Ergebnisse der Expressionsanalysen bestätigen. Sie zeigten eine Expression von Tas2rs, am Beispiel des Tas2r131-Rezeptors, in cholinergen, dopaminergen, GABAergen, noradrenergen und glycinerg-angesteuerten Projektionsneuronen sowie in Interneuronen. Die Ergebnisse der vorliegenden Arbeit zeigen daher erstmals das Vorkommen von Tas2rs in verschiedenen neuronalen Zelltypen in weiten Teilen des ZNS. Dies lässt den Schluss zu, dass Tas2r-exprimierende Zellen potentiell multiple Funktionen innehaben. Anhand von Verhaltensexperimenten in genetisch modifizierten Mäusen wurde die mögliche Funktion von Tas2r131-exprimierenden Neuronen (Tas2r131-Neurone) bei der Geschmackswahrnehmung untersucht. Die Ergebnisse weisen auf eine Beteiligung von Tas2r131-Neuronen an der Signalweiterleitung bzw. -verarbeitung der Geschmacksinformation für eine Auswahl von Bittersubstanzen hin. Die Analysen zeigen darüber hinaus, dass Tas2r131-Neuronen nicht an der Geschmackswahrnehmung anderer Bitterstoffe sowie Geschmacksstimuli anderer Qualitäten (süß, umami, sauer, salzig), beteiligt sind. Eine spezifische „Tas2r131-Bittergeschmacksbahn“, die mit anderen potentiellen „Bitterbahnen“ teils unabhängige, teils überlappende Signalwege bzw. Verarbeitungsbereiche besitzt, bildet eine mögliche zelluläre Grundlage zur Unterscheidung von Bitterstoffen. Die im Rahmen dieser Arbeit entstandene Hypothese einer potentiellen Diskriminierung von Bitterstoffen soll daher in weiterführenden Studien durch die Etablierung eines Verhaltenstest mit Mäusen geprüft werden.
Beyond the Crystal-Image
(2016)
Zu Hause
(2016)