Der Austausch von Sauerstoffisotopen zwischen Phosphat und Wasser in Modellsystemen und Böden - neue Einblicke mit Raman Spektroskopie

Das Isotopenverhältnis (O-18/O-16) in Phosphat (PO43-) kann als Tracer von biogeochemischen Prozessen in terrestrischen und aquatischen Ökosystemen genutzt werden. Bei Temperaturen unter 70°C ist die Phosphoanhydridbindung stabil aber die Aktivität von Enzymen kann den Austausch von Sauerstoffisotopen zwischen Phosphat und Wasser katalysieren. Insbesondere die intrazelluläre Pyrophosphatase führt zu einem kompletten Austausch von Sauerstoff zwischen PO43- und H2O. Dieser biochemische Prozess ist sehr wichtig, da er in allen lebenden Zellen stattfindet und somit Aufschluss darüber geben kann, ob bodenbürtiges Phosphat Teil des biologischen Kreislaufs war oder nicht. Die Extraktion und Aufreinigung von anorganischem Phosphat aus Böden vor der Messung mit einem Isotopenmassenspektrometer (IRMS) ist allerdings teuer und sehr zeit- und arbeitsintensiv. Aus diesem Grund arbeiten wir an der Entwicklung einer alternativen Methode mit dem Einsatz von Raman-Spektroskopie. In einem Modellsystem konnten wir erfolgreich die Kinetik des enzym-katalysierten Sauerstoffisotopenaustausches bestimmen. Kleine Veränderungen der Protein- und Cofaktorkonzentrationen (MgCl2) hatten einen starken Einfluss auf die Reaktionsgeschwindigkeit. Zusätzlich präsentieren wir erste Resultate über die Anwendungsmöglichkeiten dieser Technologie in natürlichen Systemen, wie zum Beispiel in Fließgewässern oder in Böden

Sauerstoffisotopenaustausch an Oxiden - Raman Messungen mit Mischungen aus Nitrat, Sulfat und Phosphat

Der Austausch der Sauerstoffisotope O-16 und O-18 ist ein Indikator für biologische Kreisläufe wichtiger Nährstoffe wie Nitrat, Sulfat oder Phosphat im Boden. Dabei setzen sich die Austauschreaktionen in realen Systemen aus verschiedenen biotischen und abiotischen Einzelreaktionen zusammen (z.B. mit und ohne Beteiligung von Mikroorganismen). Um diese verschiedenen Mechanismen unterscheiden zu können, ist es nötig mit Modellsystemen einzelne Teilmechanismen zu beschreiben. In dem Poster stellen wir erste Messungen zum abiotischen Sauerstoffisotopenaustausch mittels Raman-Spektroskopie an einer Mischung aus Nitrat, Sulfat und Phosphat vor. Raman-Spektroskopie ist eine Lichtstreumethode, die Schwingungen symmetrischer Moleküle detektiert. Da diese Molekülschwingungen von den Massen der beteiligten Atome abhängen, verändern sich bei einem Isotopenaustausch die für die Schwingungen charakteristischen Wellenzahlen der Banden im Raman-Spektrum. Bei einem schrittweisen Austausch der 3 Sauerstoffatome im Nitrat (NO3-) sind während einer Zeitreihe 4 Banden für die symmetrische N-O Valenzschwingung zu beobachten, deren Intensität (≙ Fläche unter der Bande) sich mit der Zeit ändert. Bei Sulfat (SO42-) sind wegen der 4 Sauerstoffatome 5 Banden vorhanden. Beim Phosphat (PO43-) liegen die 5 Banden so dicht, dass nur eine Umhüllende erkennbar ist, deren Maximum sich mit der Zeit verschiebt. Für eine quantitative Bestimmung der Kinetik des Isotopenaustausches muss der relative Anteil jedes Isotopologs während der Austauschreaktion als Funktion der Zeit bestimmt werden. Dazu werden die Bandensignale integriert, bzw. bei überlappten Signalen entfaltet und integriert. Für jeden Isotopologen ergibt sich so eine charakteristische Zeitkurve, die dann mit den Geschwindigkeitsgesetzen der Reaktionskinetik beschrieben werden kann. Die in diesem Poster gezeigten Arbeiten beschäftigen sich mit dem abiotischen O-16 -> O-18 Austausch einer 3-fach Mischung aus KNO3, K2SO4 und KH2PO4 in O-18 angereichertem Wasser bei Temperaturen größer als 90°C. Bei niedrigeren Temperaturen konnte kein abiotischer Sauerstoffisotopenaustausch beobachtet werden. Die Geschwindigkeitsgesetze für die Isotopologen der drei Oxide werden vorgestellt

Transputer based control system for MTLRS

The Modular Transportable Laser Ranging Systems (MTLRS-1 and MTLRS-2) have been designed in the early eighties and have been in operation very successfully since 1984. The original design of the electronic control system was based on the philosophy of parallel processing, but these ideas could at that time only be implemented to a very limited extent. This present system utilizes two MOTOROLA 6800 8-bit processors slaved to a HP A-600 micro-computer. These processors support the telescope tracking system and the data-acquisition/formatting, respectively. Nevertheless, the overall design still is largely hardware oriented. Because the system is now some nine years old, aging of components increases the risk of malfunctioning and some components or units are outdated and not available anymore. The control system for MTLRS is now being re-designed completely, based on the original philosophy of parallel processing, making use of contemporary advanced electronics and processor technology. The new design aims at the requirements for Satellite Laser Ranging (SLR) in the nineties, making use of the extensive operational experience obtained with the two transportable systems

Prevalence of Rome IV Functional Bowel Disorders Among Adults in the United States, Canada, and the United Kingdom

Background & Aims: Little is known about the population prevalence or demographic distributions of Rome IV functional bowel disorders (FBDs) or their effects on quality of life. We examined these in a multinational survey. Methods: We analyzed data from a population-based survey of adults in the United States, Canada, and United Kingdom (5931 valid responders; 49.2% female; mean age, 47.4 years; range, 18–92 years). The survey included the Rome IV Diagnostic Questionnaire, Rome III irritable bowel syndrome (IBS) and constipation questions, and the SF-8 quality of life questionnaire. Results: The prevalence values of census-adjusted Rome IV FBDs were similar among the 3 countries; ranges were: 4.4%–4.8% for IBS, 7.9%–8.6% for functional constipation, 3.6%–5.3% for functional diarrhea, 2.0%–3.9% for functional bloating or distention, 1.1%–1.9% for opioid-induced constipation, 7.5%–10.0% for unspecified FBDs, and 28.6%–31.7% for any Rome IV FBD. FBDs were less common in older individuals, and all except functional diarrhea were more common in women. IBS was only half as prevalent by Rome IV as by Rome III criteria (4.6% vs 9.0% overall), primarily due to higher Rome IV minimum pain frequency. Functional diarrhea and functional constipation were more prevalent by Rome IV than Rome III criteria. Subjects with FBD had significant reductions in quality of life and reported more gastrointestinal doctor consultations than other subjects. Conclusions: More than 1 in 4 adults in the general population meet the Rome IV criteria for FBDs. These disorders affect quality of life and increase use of gastrointestinal health care. The switch from Rome III to Rome IV criteria reduces the prevalence of IBS by half, but increases the prevalence of functional constipation and functional diarrhea

Investigating the timecourse of accessing conversational implicatures during incremental sentence interpretation

Many contextual inferences in utterance interpretation are explained as following from the nature of conversation and the assumption that participants are rational. Recent psycholinguistic research has focussed on certain of these ‘Gricean’ inferences and have revealed that comprehenders can access them in online interpretation. However there have been mixed results as to the time-course of access. Some results show that Gricean inferences can be accessed very rapidly, as rapidly as any other contextually specified information (Sedivy, 2003; Grodner, Klein, Carbery, & Tanenhaus, 2010); while other studies looking at the same kind of inference suggest that access to Gricean inferences are delayed relative to other aspects of semantic interpretation (Huang & Snedeker, 2009; in press). While previous timecourse research has focussed on Gricean inferences that support the online assignment of reference to definite expressions, the study reported here examines the timecourse of access to scalar implicatures, which enrich the meaning of an utterance beyond the semantic interpretation. Even if access to Gricean inference in support of reference assignment may be rapid, it is still unknown whether genuinely enriching scalar implicatures are delayed. Our results indicate that scalar implicatures are accessed as rapidly as other contextual inferences. The implications of our results are discussed in reference to the architecture of language comprehension

Oesophageal symptoms are common and associated with other functional gastrointestinal disorders (FGIDs) in an English-speaking Western population

mean age 46.7 years) were available for analysis. Symptom prevalence was 8.1% for globus, 6.5% for heartburn, 4.5% for dysphagia and 5.2% for chest pain, and 17.0% reported at least one oesophageal symptom. Oesophageal symptoms were independently associated with younger age, female gender, previous abdominal surgery and the presence of other functional GI disorders. Reporting oesophageal symptoms was associated with reduced quality of life. Conclusion: Oesophageal symptoms are common in the general population and important predictors include other functional GI disorders, age and gender. Oesophageal symptoms are associated with poorer quality of life.Background: The prevalence and frequency of oesophageal symptoms suggestive of a functional oesophageal disorder according to the Rome IV criteria are unknown. Objective: We aimed to describe the prevalence and risk factors for oesophageal symptoms compatible with functional oesophageal disorders in the general population. Methods: Data were analysed from a population-based online survey of 6300 individuals aged ≥ 18 years in the USA, UK and Canada with equal demographic proportions across countries. Questions included the Rome IV diagnostic questionnaire, demographics, medication, somatization, quality of life, and organic gastrointestinal (GI) disease. Multivariate analysis was used to identify factors independently related to oesophageal symptoms. Results: Data from 5177 participants (47.8% femal

Arguments for the cognitive social sciences

This article analyses the arguments for the integration between the cognitive and social sciences. We understand interdisciplinary integration as an umbrella term that includes different ways of bringing scientific disciplines together. Our focus is on four arguments based on different ideas about how the cognitive sciences should be integrated with the social sciences: explanatory grounding, theoretical unification, constraint and complementarity. These arguments not only provide different reasons why the cognitive social sciences—i.e. disciplines and research programs that aim to integrate the social sciences with the cognitive sciences—are needed but also subscribe to different visions as to how these sciences might look like. We discuss each argument in three stages: First, we provide a concrete example of the argument. Second, we reconstruct the argument by specifying its premises, inferential structure and conclusion. Third, we evaluate the argument by analyzing its presuppositions, the plausibility of its premises, the soundness of its inferences and potential conceptual ambiguities. In the final discussion, we compare these arguments and identify the most compelling reasons why the cognitive social sciences are needed.Peer reviewe

Relevance theory, pragmatic inference and cognitive architecture

Relevance Theory (RT: Sperber & Wilson, 1986) argues that human language comprehension processes tend to maximize “relevance”, and postulates that there is a relevance-based procedure that a hearer follows when trying to understand an utterance. Despite being highly influential, RT has been criticized for its failure to explain how speaker-related information, either the speaker’s abilities or her/his preferences, is incorporated into the hearer’s inferential, pragmatic process. An alternative proposal is that speaker-related information gains prominence due to representation of the speaker within higher-level goal-directed schemata. Yet the goal-based account is still unable to explain clearly how cross-domain information, for example linguistic meaning and speaker-related knowledge, is integrated within a modular system. On the basis of RT’s cognitive requirements, together with contemporary cognitive theory, we argue that this integration is realized by utilizing working memory and that there exist conversational constraints with which the constructed utterance interpretation should be consistent. We illustrate our arguments with a computational implementation of the proposed processes within a general cognitive architecture

Untangling the Conceptual Isssues Raised in Reydon and Scholz’s Critique of Organizational Ecology and Darwinian Populations

Reydon and Scholz raise doubts about the Darwinian status of organizational ecology by arguing that Darwinian principles are not applicable to organizational populations. Although their critique of organizational ecology’s typological essentialism is correct, they go on to reject the Darwinian status of organizational populations. This paper claims that the distinction between replicators and interactors, raised in modern philosophy of biology but not discussed by Reydon and Scholz, points the way forward for organizational ecologists. It is possible to conceptualise evolving Darwinian populations providing the inheritance mechanism is appropriately specified. By this approach, adaptation and selection are no longer dichotomised, and the evolutionary significance of knowledge transmission is highlightedPeer reviewe

Learning From Early Attempts to Generalize Darwinian Principles to Social Evolution

Copyright University of Hertfordshire & author.Evolutionary psychology places the human psyche in the context of evolution, and addresses the Darwinian processes involved, particularly at the level of genetic evolution. A logically separate and potentially complementary argument is to consider the application of Darwinian principles not only to genes but also to social entities and processes. This idea of extending Darwinian principles was suggested by Darwin himself. Attempts to do this appeared as early as the 1870s and proliferated until the early twentieth century. But such ideas remained dormant in the social sciences from the 1920s until after the Second World War. Some lessons can be learned from this earlier period, particularly concerning the problem of specifying the social units of selection or replication