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Das Drama des 17. Jahrhunderts steht nicht in einem ästhetischen, sondern als Argument in einem sozialen, politischen oder, in der Sprache der Zeit, moralphilosophischen Kontext. Ein erster Teil des Aufsatzes zeigt, dass die Poetik in der aristotelischen Schulphilosophie als Teil der Logik, das heißt der Argumentationstheorie im weitesten Sinne galt, und die Dichtung selbst somit als Anwendung einer argumentativen Form. Ein zweiter Teil zeigt an drei Beispielen, dass diese logische, argumentationstheoretische Auffassung des Dramas auch den Poetiken der Zeit zugrunde liegt. Ein dritter Teil führt an einigen Dramen (u.a. Gryphius’ „Catharina von Georgien“, Masens „Androphilus“ und Birkens „Silvia“) kurz vor, in welcher Form sie als Argument zu verstehen sind. Der vierte Teil zeigt, dass die Auffassung des Dramas als Argument ihren sozialhistorischen Kontext im Schultheater hat. Ein letzter Teil widmet sich der Frage, was nach Überzeugung der Frühen Neuzeit die Eigentümlichkeit des Dramas ausmacht, wenn es sich als Argument nicht von anderen Argumentationsformen unterscheidet.
1455a 32-34 heißt es in der „Poetik“ des Aristoteles, dass die Dichter entweder begabt oder von einem göttlichen Wahnsinn (furor poeticus) besessen seien. Damit scheint es sich bei diesem Satz um die einzige Stelle zu handeln, an der Aristoteles eine göttliche Entrückung der Dichter in Betracht zieht. Die Kommentatoren des 16. Jahrhunderts haben deshalb viel philologischen Scharfsinn auf den Versuch verwendet, diese Stelle so zu deuten, dass sie zur Konzeption der Dichtung als einer technischen Fähigkeit, wie sie die „Poetik“ entwickelt, nicht in Widerspruch steht. Mehr oder weniger explizit wenden sie sich dabei gegen die neuplatonische Enthusiasmus-Theorie Marsilio Ficinos.
We present an approach to generate (multivariate) twin surrogates (TS) based on recurrence properties. This technique generates surrogates which correspond to an independent copy of the underlying system, i. e. they induce a trajectory of the underlying system starting at different initial conditions. We show that these surrogates are well suited to test for complex synchronisation and exemplify this for the paradigmatic system of R¨ossler oscillators. The proposed test enables to assess the statistical relevance of a synchronisation analysis from passive experiments which are typical in natural systems.
Reading requires the orchestration of visual, attentional, language-related, and oculomotor processing constraints. This study replicates previous effects of frequency, predictability, and length of fixated words on fixation durations in natural reading and demonstrates new effects of these variables related to previous and next words. Results are based on fixation durations recorded from 222 persons, each reading 144 sentences. Such evidence for distributed processing of words across fixation durations challenges psycholinguistic immediacy-of-processing and eye-mind assumptions. Most of the time the mind processes several words in parallel at different perceptual and cognitive levels. Eye movements can help to unravel these processes.
When the eyes fixate at a point in a visual scene, small saccades rapidly shift the image on the retina. The effect of these microsaccades on the latency of subsequent large-scale saccades may be twofold. First, microsaccades are associated with an enhancement of visual perception. Their occurrence during saccade target perception should, thus, decrease saccade latencies. On the other hand, microsaccades likely indicate activity in fixation-related oculomotor neurons. These represent competitors to saccade-related cells in the interplay of gaze holding and shifting. Consequently, an increase in saccade latencies after microsaccades would be expected. Here, we present evidence for both aspects of microsaccadic impact on saccade latency. In a delayed response task, participants made saccades to visible or memorized targets. First, microsaccade occurrence up to 50 ms before target disappearance correlated with 18 ms (or 8%) faster saccades to memorized targets. Second, if microsaccades occurred shortly (i.e., < 150 ms) before a saccade was required, saccadic reaction times in visual and memory trials were increased by about 40 ms (or 16%). Hence, microsaccades can have opposite consequences for saccade latencies, pointing at a differential role of these fixational eye movements in preparation of motor programs.
In this paper we present an approach to recover the dynamics from recurrences of a system and then generate (multivariate) twin surrogate (TS) trajectories. In contrast to other approaches, such as the linear-like surrogates, this technique produces surrogates which correspond to an independent copy of the underlying system, i. e. they induce a trajectory of the underlying system visiting the attractor in a different way. We show that these surrogates are well suited to test for complex synchronization, which makes it possible to systematically assess the reliability of synchronization analyses. We then apply the TS to study binocular fixational movements and find strong indications that the fixational movements of the left and right eye are phase synchronized. This result indicates that there might be one centre only in the brain that produces the fixational movements in both eyes or a close link between two centres.
Forum: EU-Diplomatie im Jahre 2020
Forum: EU-Diplomatie im Jahre 2020
Forum: EU-Diplomatie im Jahre 2020
Prolog (zum Forum)
(2006)
Die EU ist überdehnt. Drei verschiedene, koexistierende Europavisionen erklären den derzeitigen Strategiemangel: Das pragmatische Europa ist nicht transparent, das grenzenlose Europa fördert Ängste unkontrollierbarer Veränderungen, und das Identitäs- Europa befindet sich in einer Sinnkrise. Antwort bieten mehrere Strategien: Ein Transfer einzelner Elemente der europäischen Verfassung in einen Europavertrag; Orientierung an einem differenzierten Europa und Bildung von Koalitionen, um Europa zu führen.
Editorial
(2006)
Soil seed banks near rubbing trees indicate dispersal of plant species into forests by wild boar
(2006)
Current knowledge about processes that generate long-distance dispersal of plants is still limited despite its importance for persistence of populations and colonization of new potential habitats. Today wild large mammals are presumed to be important vectors for long-distance transport of diaspores within and between European temperate forest patches, and in particular wild boars recently came into focus. Here we use a specific habit of wild boar, i.e. wallowing in mud and subsequent rubbing against trees, to evaluate epizoic dispersal of vascular plant diaspores. We present soil seed bank data from 27 rubbing trees versus 27 control trees from seven forest areas in Germany. The mean number of viable seeds and the plant species number were higher in soil samples near rubbing trees compared with control trees. Ten of the 20 most frequent species were more frequent, and many species exclusively appeared in the soil samples near rubbing trees. The large number of plant species and seeds – approximated > 1000 per tree – in the soils near rubbing trees is difficult to explain unless the majority were dispersed by wild boar. Hooked and bristly diaspores, i.e. those adapted to epizoochory, were more frequent, above that many species with unspecialised diaspores occurred exclusively near rubbing trees. Different to plant species closely tied to forest species which occur both in forest and open vegetation, and non-forest species were more frequent near rubbing trees compared with controls. These findings are consistent with previous studies on diaspore loads in the coats and hooves of shot wild boars. However, our method allows to identify the transport of diaspores from the open landscape into forest stands where they might especially emerge after disturbance, and a clustered distribution of epizoochorically dispersed seeds. Moreover, accumulation of seeds of wetness indicators near rubbing trees demonstrates directed dispersal of plant species inhabiting wet places between remote wallows.
The biogenic amine serotonin (5-HT) plays a key role in the regulation and modulation of many physiological and behavioural processes in both vertebrates and invertebrates. These functions are mediated through the binding of serotonin to its receptors, of which 13 subtypes have been characterized in vertebrates. We have isolated a cDNA from the honeybee Apis mellifera (Am5-ht7) sharing high similarity to members of the 5-HT7 receptor family. Expression of the Am5-HT7 receptor in HEK293 cells results in an increase in basal cAMP levels, suggesting that Am5-HT7 is expressed as a constitutively active receptor. Serotonin application to Am5-ht7-transfected cells elevates cyclic adenosine 3',5'-monophosphate (cAMP) levels in a dose-dependent manner (EC50 = 1.1-1.8 nM). The Am5-HT7 receptor is also activated by 5-carboxamidotryptamine, whereas methiothepin acts as an inverse agonist. Receptor expression has been investigated by RT-PCR, in situ hybridization, and western blotting experiments. Receptor mRNA is expressed in the perikarya of various brain neuropils, including intrinsic mushroom body neurons, and in peripheral organs. This study marks the first comprehensive characterization of a serotonin receptor in the honeybee and should facilitate further analysis of the role(s) of the receptor in mediating the various central and peripheral effects of 5-HT.
Biogenic amines are important messenger substances in the central nervous system and in peripheral organs of vertebrates and of invertebrates. The honeybee, Apis mellifera, is excellently suited to uncover the functions of biogenic amines in behaviour, because it has an extensive behavioural repertoire, with a number of biogenic amine receptors characterised in this insect. In the honeybee, the biogenic amines dopamine, octopamine, serotonin and tyramine modulate neuronal functions in various ways. Dopamine and serotonin are present in high concentrations in the bee brain, whereas octopamine and tyramine are less abundant. Octopamine is a key molecule for the control of honeybee behaviour. It generally has an arousing effect and leads to higher sensitivity for sensory inputs, better learning performance and increased foraging behaviour. Tyramine has been suggested to act antagonistically to octopamine, but only few experimental data are available for this amine. Dopamine and serotonin often have antagonistic or inhibitory effects as compared to octopamine. Biogenic amines bind to membrane receptors that primarily belong to the large gene-family of GTP-binding (G) protein coupled receptors. Receptor activation leads to transient changes in concentrations of intracellular second messengers such as cAMP, IP3 and/or Ca2+. Although several biogenic amine receptors from the honeybee have been cloned and characterised more recently, many genes still remain to be identified. The availability of the completely sequenced genome of Apis mellifera will contribute substantially to closing this gap. In this review, we will discuss the present knowledge on how biogenic amines and their receptor-mediated cellular responses modulate different behaviours of honeybees including learning processes and division of labour.
G protein-coupled receptor (GPCR) genes are large gene families in every animal, sometimes making up to 1-2% of the animal's genome. Of all insect GPCRs, the neurohormone (neuropeptide, protein hormone, biogenic amine) GPCRs are especially important, because they, together with their ligands, occupy a high hierarchic position in the physiology of insects and steer crucial processes such as development, reproduction, and behavior. In this paper, we give a review of our current knowledge on Drosophila melanogaster GPCRs and use this information to annotate the neurohormone GPCR genes present in the recently sequenced genome from the honey bee Apis mellifera. We found 35 neuropeptide receptor genes in the honey bee (44 in Drosophila) and two genes, coding for leucine-rich repeats-containing protein hormone GPCRs (4 in Drosophila). In addition, the honey bee has 19 biogenic amine receptor genes (21 in Drosophila). The larger numbers of neurohormone receptors in Drosophila are probably due to gene duplications that occurred during recent evolution of the fly. Our analyses also yielded the likely ligands for 40 of the 56 honey bee neurohormone GPCRs identified in this study. In addition, we made some interesting observations on neurohormone GPCR evolution and the evolution and co-evolution of their ligands. For neuropeptide and protein hormone GPCRs, there appears to be a general co-evolution between receptors and their ligands. This is in contrast to biogenic amine GPCRs, where evolutionarily unrelated GPCRs often bind to the same biogenic amine, suggesting frequent ligand exchanges ("ligand hops") during GPCR evolution. (c) 2006 Elsevier Ltd. All rights reserved.
Der Beitrag stellt die verschiedenen Judaica- und Hebraica-Bestände und ihre Schwerpunkte in der chronologischen Reihenfolge vor, in der sie in die Universitätsbibliothek Potsdam gelangten. Abgesehen von anderen Sammlungen - wie z.B. der Israel-Mehlmann-Bibliothek und der Israil-Bercovici-Bibliothek, die Werke zu allen Bereichen der Jüdischen Studien enthalten - macht die Aschkenasy-Bibliothek den wertvollsten Bestand aus. Sie enthält die frühere Bibliothek des Bet ha-Midrasch, das von Veitel Heine Ephraim, dem Hofjuwelier Friedrich II., gegründet wurde. Die Aschkenasy-Sammlung beinhaltet nicht nur zahlreiche Titel der traditionellen jüdischen Literatur, welche seit 1550 gedruckt wurden, sondern auch Forschungsliteratur und 58 jemenitische Handschriften aus dem 17. und 18. Jahrhundert.
Bezogen auf das Bruttoinlandsprodukt ist China eine wichtige regionale Wirtschaftsmacht, aber keine Supermacht. Doch das Wachstumspotential zehrt sich auf, auch weil die Investitionsdynamik der Unternehmen und der Bankensektor härteren Kreditrestriktionen unterworfen werden. Chinas bislang geschütztes Finanzsystem, das von der Globalisierung untergraben wird, ist die Achillesferse für das hohe Wachstum.
Aus Warschauer Perspektive
(2006)
Neue Akzente statt Neubeginn
(2006)
Auszug: "Man kann Motivation definieren als die „aktivierende Ausrichtung des momentanen Lebensvollzugs auf einen positiv bewerteten Zielzustand“ (Rheinberg, 2002b, S. 17). Definitionen dieser Art sollen den Kern des interessierenden Gegenstandes möglichst knapp und hoch verdichtet fassen. Besonderheiten bleiben deshalb zunächst unerwähnt und müssen dann zusätzlich erläutert werden. Im jetzigen Fall sind mindestens zwei Zusatzerläuterungen erforderlich. (1) Der „positiv bewertete Zielzustand“ kann gelegentlich in der Vermeidung oder der Abwehr unerwünschter Ereignisse bestehen. Eine solche Meiden-Motivation kann andere Qualitäten haben als eine reine Aufsuchungsmotivation. Dieser Punkt wird uns in diesem Kapitel nicht beschäftigen. Er wird in den Kapiteln xx behandelt. (2) Der zweite Punkt ist diffiziler und ist Gegenstand dieses Kapitels. Wenn man, wie hier, den Zielzustand zum Ausgangspunkt der Motivationsdefinition macht, so könnte man daraus vorschnell eine Aussage über die Lokalisierung von Anreizen ablesen: Der Zielzustand ist das, was Anreiz besitzt und die zielführende Aktivität ist lediglich das Instrument, das diesen Zielzustand herbeiführt. Danach würde eine Aktivität ihre Attraktivität aus dem Anreiz der Ergebnisse beziehen, auf die sie abzielt. Eine solche Auffassung findet sich z. B. bei Heckhausen (1977) oder Vroom (1964).
In Allefeld & Kurths [2004], we introduced an approach to multivariate phase synchronization analysis in the form of a Synchronization Cluster Analysis (SCA). A statistical model of a synchronization cluster was described, and an abbreviated instruction on how to apply this model to empirical data was given, while an implementation of the corresponding algorithm was (and is) available from the authors. In this letter, the complete details on how the data analysis algorithm is to be derived from the model are filled in.
Anreizanalyse intensiver Freizeitnutzung von Computern : Hacker, Cracker und zweckorientierte Nutzer
(2006)
Was bringt intensive Computernutzer dazu, ihre Freizeit am Rechner zu verbringen, und gibt es hierbei Unterschiede zwischen verschiedenen Nutzertypen? N = 271 Personen nahmen an einer online Befragung zu Anreizen freizeitlicher Computernutzung teil. Durch ausgewählte Internetverteiler waren gezielt besonders engagierte Computernutzer angesprochen worden (M = 3,9 Freizeitstunden am Rechner pro Tag). Für diese Nutzer fanden sich (in der Reihenfolge ihres Gewichtes) folgende Anreizfaktoren: Zugehörigkeit/Gemeinschaft; Kompetenzerleben; Vielseitigkeit/Nutzen; Langeweilevermeidung; rebellische Illegalitätstendenz. Gruppiert nach ihren bevorzugten Nutzungsweisen fanden sich drei Nutzertypen: Zweckorientierte Nutzer (58%), Hacker (= Eindringen in fremde Systeme ohne Schädigungsabsicht, 22%) und Cracker (Eindringen mit Schädigungsabsicht, 20%). Diese Nutzertypen unterschieden sich deutlich in ihrem Anreizprofil. Hacking und Cracking, nicht aber zweckorientierte Nutzungsweisen waren korreliert mit Flow-Erleben und positiver Aktivierung am Rechner. Die Ergebnisse sind nicht repräsentativ für alle Freizeitnutzer. Sie beziehen sich auf eine gezielt rekrutierte Stichprobe besonders engagierter Computernutzer, die über spezifische Netzwerke (z. B. relevante Fachschaften, Chaos Computer Club) erreichbar sind.
In this study the effect of phonotactic constraints concerning word-initial consonant clusters in children with delayed phonological acquisition was explored. Twelve German-speaking children took part (mean age 5;1). The spontaneous speech of all children was characterized by the regular appearance of the error patterns fronting, e.g., Kuh (cow) → /tu:/, or stopping, e.g., Schaf (sheep) → /ta:f/, which were inappropriate for their chronological age. The children were asked to produce words (picture naming task, word repetition task) with initial consonant clusters, in which the application of the error patterns would violate phonotactic sequence constraints. For instance, if fronting would apply in /kl-/, e.g., Kleid (dress), it would be realized as the phontactically illegal consonant cluster /tl-/. The results indicate that phonotactic constraints affect word production in children with delayed phonological developments. Surprisingly, we found that children with fronting produced the critical consonants correctly significantly more often in word-initial consonant clusters than in words in which they appeared as singleton onsets. In addition, the results provide evidence for a similar developmental trajectory of acquisition in children with typical development and in children with delayed phonological acquisition. Keywords: Children with delayed phonological acquisition, phonotactic constraints, word-initial consonant clusters, fronting, stopping.
Recent research has shown that the early lexical representations children establish in their second year of life already seem to be phonologically detailed enough to allow differentiation from very similar forms. In contrast to these findings children with specific language impairment show problems in discriminating phonologically similar word forms up to school age. In our study we investigated the question whether there would be differences in the processing of phonological details in normally developing and in children with low language performance in the second year of life. This was done by a retrospective study in which in the processing of phonological details was tested by a preferential looking experiment when the children were 19 months old. At the age of 30 months children were tested with a standardized German test of language comprehension and production (SETK2). The preferential looking data at 19 months revealed an opposite reaction pattern for the two groups: while the children scoring normally in the SETK2 increase their fixations of a pictured object only when it was named with the correct word, children with later low language performance did so only when presented with a phonologically slightly deviant mispronunciation. We suggest that this pattern does not point to a specific deficit in processing phonological information in these children but might be related to an instability of early phonological representations, and/or a generalized problem of information processing as compared to typically developing children.
Recent work has shown that English-learning 18-month-olds can detect the relationship between discontinuous morphemes such as is and -ing in Grandma is always running (Gomez, 2002; Santelmann & Jusczyk, 1998) but only at a maximum of 3 intervening syllables. In this article we examine the tracking of discontinuous dependencies in children acquiring German. Due to freer word order, German allows for greater distances between dependent elements and a greater syntactic variety of the intervening elements than English does. The aim of this study was to investigate whether factors other than distance may influence the child’s capacity to recognize discontinuous elements. Our findings provide evidence that children’s recognition capacities are affected not only by distance but also by their ability to linguistically analyze the material intervening between the dependent elements. We speculate that this result supports the existence of processing mechanisms that reduce a discontinuous relation to a local one based on subcategorization relations.
Global Circulation Models of climate predict not only a change of annual precipitation amounts but also a shift in the daily distribution. To improve the understanding of the importance of daily rain pattern for annual plant communities, which represent a large portion of semi-natural vegetation in the Middle East, I used a detailed, spatially explicit model. The model explicitly considers water storage in the soil and has been parameterized and validated with data collected in field experiments in Israel and data from the literature. I manipulated daily rainfall variability by increasing the mean daily rain intensity on rainy days (MDI, rain volume/day) and decreasing intervals between rainy days while keeping the mean annual amount constant. In factorial combination, I also increased mean annual precipitation (MAP). I considered five climatic regions characterized by 100, 300, 450, 600, and 800 mm MAP. Increasing MDI decreased establishment when MAP was >250 mm but increased establishment at more arid sites. The negative effect of increasing MDI was compensated by increasing mortality with increasing MDI in dry and typical Mediterranean regions (c. 360–720 mm MAP). These effects were strongly tied to water availability in upper and lower soil layers and modified by competition among seedlings and adults. Increasing MAP generally increased water availability, establishment, and density. The order of magnitudes of MDI and MAP effects overlapped partially so that their combined effect is important for projections of climate change effects on annual vegetation. The effect size of MAP and MDI followed a sigmoid curve along the MAP gradient indicating that the semi-arid region (≈300 mm MAP) is the most sensitive to precipitation change with regard to annual communitie
This contribution describes a generator of stochastic time series of daily precipitation for the interior of Israel from c. 90 to 900 mm mean annual precipitation (MAP) as a tool for studies of daily rain variability. The probability of rainfall on a given day of the year is described by a regular Gaussian peak curve function. The amount of rain is drawn randomly from an exponential distribution whose mean is the daily mean rain amount (averaged across years for each day of the year) described by a flattened Gaussian peak curve. Parameters for the curves have been calculated from monthly aggregated, long-term rain records from seven meteorological stations. Parameters for arbitrary points on the MAP gradient are calculated from a regression equation with MAP as the only independent variable. The simple structure of the generator allows it to produce time series with daily rain patterns that are projected under climate change scenarios and simultaneously control MAP. Increasing within-year variability of daily precipitation amounts also increases among-year variability of MAP as predicted by global circulation models. Thus, the time series incorporate important characteristics for climate change research and represent a flexible tool for simulations of daily vegetation or surface hydrology dynamics.
Aus dem Inhalt: Die Frage „Wie lernen Erwachsene?“ lässt sich in zweierlei Hinsicht lesen. Einmal als empirische Frage nach den Zielen, Verläufen und Schwierigkeiten in den Lernprozessen und Lernhandlungen Erwachsener und zum anderen als normativ-konzeptionelle Frage nach motivierenden oder „richtigen“ Lernstrategien im Sinne eines Lernen-Machens, eines Anleitens und Hinführens.
Der Beitrag stellt lerntheoretische und didaktische Begründungen sowie die bildungspraktische Umsetzung für ein didaktisches Konzept der Lernberatung im virtuellen Raum vor. Das Lernberatungskonzept wurde im Rahmen des vom BMBF geförderten Projekts be-online entwickelt. Einleitend wird der Frage nachgegangen, welche online-didaktischen Konzepte zur Unterstützung von Lernprozessen im virtuellen Raum vorliegen, um Anknüpfungspunkte und Differenzen für das Konzept der Lernberatung im virtuellen Raum aufzuzeigen.
China ist auf dem Weg zu einer offeneren Gesellschaft mit zunehmender Partizipation, größerer rechtlicher Sicherheit und individueller Autonomie. Der Staat zog sich aus vielen Bereichen zurück, ökonomische Ziele bestimmen seine Prioritäten. Die Entwicklungserfolge brachten jedoch eine Legitimationskrise des Staates mit sich. Vier Dilemmata, die China heute konfrontieren, werden aufgezeigt und Hypothesen zur Charakterisierung des chinesischen party state diskutiert.
Chinas Wandel und die Welt
(2006)
Wie stellt sich das Verhältnis zwischen China und der Welt im 21. Jahrhundert dar? Die Autorin, Politikwissenschaftlerin aus Peking, verweist auf die aktuelle Debatte in China, in der das Primat der Innenpolitik, regionaler Multilateralismus und harmonische Weltordnung intensiv diskutiert werden. China habe nicht vor, das internationale System herauszufordern oder zu zerstören. Vielmehr sei es um stärkere Einbindung bemüht.
Germination rates and germination fractions of seeds can be predicted well by the hydrothermal time (HTT) model. Its four parameters hydrothermal time, minimum soil temperature, minimum soil moisture, and variation of minimum soil moisture, however, must be determined by lengthy germination experiments at combinations of several levels of soil temperature and moisture. For some applications of the HTT model it is more important to have approximate estimates for many species rather than exact values for only a few species. We suggest that minimum temperature and variation of minimum moisture can be estimated from literature data and expert knowledge. This allows to derive hydrothermal time and minimum moisture from existing data from germination experiments with one level of temperature and moisture. We applied our approach to a germination experiment comparing germination fractions of wild annual species along an aridity gradient in Israel. Using this simplified approach we estimated hydrothermal time and minimum moisture of 36 species. Comparison with exact data for three species shows that our method is a simple but effective method for obtaining parameters for the HTT model. Hydrothermal time and minimum moisture supposedly indicate climate related germination strategies. We tested whether these two parameters varied with the climate at the site where the seeds had been collected. We found no consistent variation with climate across species, suggesting that variation is more strongly controlled by site-specific factors.
Die Anwendung zweier ähnlicher fasergekoppelte Diodenlaser-Spektrometer-Systeme werden vorgestellt. Basis sind handelsübliche DFB-Laserdioden der optischen Kommunikationstechnik. Der faseroptische Aufbau, das Detektionsverfahren (2f Wellenlängenmodulations-Spektroskopie mit Balanced Receiver), Rauschverhalten und Detektionslimit werden diskutiert. Zur in-situ Plasma-Diagnostik von CO- und CO2-Konzentrationen in industriellen CO2-Lasern der Materialbearbeitung wurde eine Wellenlänge von 1582 nm verwendet. Bei einem Gasdruck von 100 hPa und einer Absorptionsweglänge von 14,9 cm wurden mit einer Laserdiode simultan CO- und CO2-Konzentrationen von 0% bis 11% im Gasgefäß bei laufender Hochfrequenzgasentladung des CO2-Lasers zeitaufgelöst gemessen. Vorgestellt und diskutiert werden Aufbau und Eigenschaften des Spektrometers sowie die Ergebnisse der dynamischen Gasanalysen, die zu einer Verbesserung der Katalysator-Technik im CO2-Laser beigetragen haben.Mit isotopenaufgelöster CO- und CO2-Spektroskopie können biologische Gasaustauschprozesse, z.B. in Gasen aus dem Erdboden untersucht werden. Hierzu wurde ein fasergekoppeltes feldtaugliches Diodenlaser-Spektrometer bei Wellenlängen um 1605 nm zur Messungder Isotopologe 12C16O, 13C16O, 12C18O und 12C16O2, 13C16O2, 12C18O16O aufgebaut. Die Messung erfolgt extraktiv in Langwegzellen mit unterschiedlichen Absorptionsweglängen von 100.9 m und 29.9 m. Es werden Kalibrationsmessungen zur Linearität und zur Präzision der Bestimmung der Isotopenverhältnisse sowie Wiederholungsmessungen zur Stabilität vorgestellt. Nachweisgrenzen von wenigen ppm konnten für die CO- und CO2-Isotopologen erhalten werden.
Optical methods play an important role in process analytical technologies (PAT). Four examples of optical process and quality sensing (OPQS) are presented, which are based on three important experimental techniques: near-infrared absorption, luminescence quenching, and a novel method, photon density wave (PDW) spectroscopy. These are used to evaluate four process and quality parameters related to beer brewing and polyurethane (PU) foaming processes: the ethanol content and the oxygen (O2) content in beer, the biomass in a bioreactor, and the cellular structures of PU foam produced in a pilot production plant.
The salivary glands of the blowfly were injected with luminescent oxygen-sensitive microbeads. The changes in oxygen content within individual gland tubules during hormone-induced secretory activity were quantified. The measurements are based on an upgraded phase-modulation technique, where the phase shift of the sensor phosphorescence is determined independently from concentration and background signals. We show that the combination of a lock-in amplifier with a fluorescence microscope results in a convenient setup to measure oxygen concentrations within living animal tissues at the cellular level.
Quantum dots (QDs) are common as luminescing markers for imaging in biological applications because their optical properties seem to be inert against their surrounding solvent. This, together with broad and strong absorption bands and intense, sharp tuneable luminescence bands, makes them interesting candidates for methods utilizing Forster Resonance Energy Transfer (FRET), e. g. for sensitive homogeneous fluoroimmunoassays (FIA). In this work we demonstrate energy transfer from Eu3+-trisbipyridin (Eu-TBP) donors to CdSe-ZnS-QD acceptors in solutions with and without serum. The QDs are commercially available CdSe-ZnS core-shell particles emitting at 655 nm (QD655). The FRET system was achieved by the binding of the streptavidin conjugated donors with the biotin conjugated acceptors. After excitation of Eu-TBP and as result of the energy transfer, the luminescence of the QD655 acceptors also showed lengthened decay times like the donors. The energy transfer efficiency, as calculated from the decay times of the bound and the unbound components, amounted to 37%. The Forster-radius, estimated from the absorption and emission bands, was ca. 77Å. The effective binding ratio, which not only depends on the ratio of binding pairs but also on unspecific binding, was obtained from the donor emission dependent on the concentration. As serum promotes unspecific binding, the overall FRET efficiency of the assay was reduced. We conclude that QDs are good substitutes for acceptors in FRET if combined with slow decay donors like Europium. The investigation of the influence of the serum provides guidance towards improving binding properties of QD assays.
Improvement of a fluorescence immunoassay with a compact diode-pumped solid state laser at 315 nm
(2006)
We demonstrate the improvement of fluorescence immunoassay (FIA) diagnostics in deploying a newly developed compact diode-pumped solid state (DPSS) laser with emission at 315 nm. The laser is based on the quasi-three-level transition in Nd:YAG at 946 nm. The pulsed operation is either realized by an active Q-switch using an electro-optical device or by introduction of a Cr<SUP>4+</SUP>:YAG saturable absorber as passive Q-switch element. By extra-cavity second harmonic generation in different nonlinear crystal media we obtained blue light at 473 nm. Subsequent mixing of the fundamental and the second harmonic in a β-barium-borate crystal provided pulsed emission at 315 nm with up to 20 μJ maximum pulse energy and 17 ns pulse duration. Substitution of a nitrogen laser in a FIA diagnostics system by the DPSS laser succeeded in considerable improvement of the detection limit. Despite significantly lower pulse energies (7 μJ DPSS laser versus 150 μJ nitrogen laser), in preliminary investigations the limit of detection was reduced by a factor of three for a typical FIA.
Near-infrared (NIR) absorption spectroscopy with tunable diode lasers allows the simultaneous detection of the three most important isotopologues of carbon dioxide (<SUP>12</SUP>CO<SUB>2</SUB>, <SUP>13</SUP>CO<SUB>2</SUB>, <SUP>12</SUP>C<SUP>18</SUP>O<SUP>16</SUP>O) and carbon monoxide (<SUP>12</SUP>CO, <SUP>13</SUP>CO, <SUP>12</SUP>C<SUP>18</SUP>O). The flexible and compact fiber-optic tunable diode laser absorption spectrometer (TDLAS) allows selective measurements of CO<SUB>2</SUB> and CO with high isotopic resolution without sample preparation since there is no interference with water vapour. For each species, linear calibration plots with a dynamic range of four orders of magnitude and detection limits (LOD) in the range of a few ppm were obtained utilizing wavelength modulation spectroscopy (WMS) with balanced detection in a Herriott-type multipass cell. The high performance of the apparatus is illustrated by fill-evacuation-refill cycles.
Two examples of our biophotonic research utilizing nanoparticles are presented, namely laser-based fluoroimmuno analysis and in-vivo optical oxygen monitoring. Results of the work include significantly enhanced sensitivity of a homogeneous fluorescence immunoassay and markedly improved spatial resolution of oxygen gradients in root nodules of a legume species.
Mit diesem Heft wird die Diskussion über eine neue deutsche Ostpolitik fortgesetzt und abgeschlossen. Diese hatte im Heft Nr. 49 mit Thesen von Jochen Franzke begonnen, im nächsten Heft wurden erste Beiträge publiziert. Insgesamt haben sich Wissenschaftler und Politiker aus Deutschland, Österreich, Polen, Finnland und Tschechien beteiligt. Die Debatte schließt mit Schlussbemerkungen des Initiators. Ulrich Best, Katrin Böttger, Vladimir Handl, Heinz Timmermann, Christian Wipperfürth, Sabina Wölkner, Gesine Schwan, Dieter Segert, Beata Wilga, Markus Löning und Ole Diehl, Angelica Schwall-Düren, Wolfgang Gehrcke und Jochen Franzke
Mit diesem Heft wird die Diskussion über eine neue deutsche Ostpolitik fortgesetzt und abgeschlossen. Diese hatte im Heft Nr. 49 mit Thesen von Jochen Franzke begonnen, im nächsten Heft wurden erste Beiträge publiziert. Insgesamt haben sich Wissenschaftler und Politiker aus Deutschland, Österreich, Polen, Finnland und Tschechien beteiligt. Die Debatte schließt mit Schlussbemerkungen des Initiators. Ulrich Best, Katrin Böttger, Vladimir Handl, Heinz Timmermann, Christian Wipperfürth, Sabina Wölkner, Gesine Schwan, Dieter Segert, Beata Wilga, Markus Löning und Ole Diehl, Angelica Schwall-Düren, Wolfgang Gehrcke und Jochen Franzke
In den theoretischen Grundlagen moderner Verfassungsstaaten wird Angst als zentrale politische Größe ausgewiesen. In der Hobbesschen Ursprungsmythologie moderner Staatlichkeit spielt sie eine entscheidende Rolle für die Staatskonstituierung. Aufgrund ihrer Staatszentriertheit bietet die Vertragstheorie allerdings kein hinreichendes Erklärungspotential für die transnationale terroristische Strategie der Angst. Der Angstpolitik des Terrorismus steht aber auch eine Nutzbarmachung der Angst durch Regierungen bedrohter Staaten gegenüber.