IRS organigram

Charts and graphs relative to magnetoplasmadynamic (MPD) thruster technology are given. The research activities at the Institute of Space Transportation, University of Stuttgart, are summarized. Information is given on the Institute's Electric Propulsion and Plasma Wind Tunnel; thermal arcjet research; the nozzle-type thruster, DT-IRS; nozzle-type MPD thrusters; a hot anode thruster; the DT6 thruster; the ZT-1 thruster; the cylindrical MPD thruster; and a comparison of continuous and quasi-steady MPD

Misrepresenting the Jordan River Basin

This article advances a critique of the UN Economic and Social Commission for West Asia’s (ESCWA’s) representation of the Jordan River Basin, as contained in its recently published Inventory of Shared Water Resources in Western Asia. We argue that ESCWA’s representation of the Jordan Basin is marked by serious technical errors and a systematic bias in favour of one riparian, Israel, and against the Jordan River’s four Arab riparians. We demonstrate this in relation to ESCWA’s account of the political geography of the Jordan River Basin, which foregrounds Israel and its perspectives and narratives; in relation to hydrology, where Israel’s contribution to the basin is overstated, whilst that of Arab riparians is understated; and in relation to development and abstraction, where Israel’s transformation and use of the basin are underplayed, while Arab impacts are exaggerated. Taken together, this bundle of misrepresentations conveys the impression that it is Israel which is the main contributor to the Jordan River Basin, Arab riparians its chief exploiters. This impression is, we argue, not just false but also surprising, given that the Inventory is in the name of an organisation of Arab states. The evidence discussed here provides a striking illustration of how hegemonic hydro-political narratives are reproduced, including by actors other than basin hegemons themselves

Zerstäubung von Flüssigkeiten in einer nicht angepassten Lavaldüse

Bei der Entspannungsströmung eines Gases durch eine Lavaldüse entsprechender Auslegung, tritt innerhalb dieser ein Verdichtungsstoß auf. Er ändert in einer Störungsfront im Bereich weniger Mikrometer schlagartig die Geschwindigkeit, den Druck, die Dichte, Temperatur und Entropie der Strömung. Mit Hilfe von Mikrobohrungen wird der Druckverlauf innerhalb der Lavalströmung ermittelt und der Verdichtungsstoß im Experiment bestätigt. Eine grobdisperse, flüssige Phase wird beim Durchgang durch den Verdichtungsstoß in wesentlich kleinere Tropfen zerteilt. So lassen sich mit relativ niedrigen Gasdrücken und hohem Flüssigkeitsdurchsatz Aerosole von wenigen Mikrometern Tropfengröße erzeugen. In einem Laborprüfstand wird der Einsatz der Lavaldüse zu Erzeugung eines therapeutisch nutzbaren Inhalationsaerosols untersucht und das erzeugte Aerosol mittels Laserbeugungsspektroskopie charakterisiert. Der sich an die Verdichtungsstöße anschließende Teil der Lavaldüse hat einen negativen Effekt auf die Feinheit des Aerosols. Es wird gezeigt, wie das Kürzen der Lavaldüse den Verdichtungsstoß relativ zur Gesamtlänge der Düse stromabwärts verschiebt. Im Ergebnis erhöht sich die Feinheit des erzeugten Aerosols sowohl im stationären als auch instationären Gasstrom.Atomization of liquids with an over expanding laval nozzle During the relaxation gasflow through a laval nozzle with given theoretical outlet gas pressure a shockwave occurs inside the nozzle. This shockwave is accompanied by a dramatic change of velocity, pressure, density, temperature and entropy within few a micrometers of flow. Through small drill holes the pressure inside the nozzle is monitored at multiple points and the shockwave is proven experimentally. By passing through the nozzle droplets with a coarse distribution are broken up into a fine aerosol. So it is possible to obtain an aerosol of only a few micrometers droplet size using relatively low pressure and high liquid flowrates. In a laboratory assembly the useability of the laval nozzle for the generation of an inhalation aerosol is investigated. The size distribution of the produced aerosol is characterised by laser diffraction.The downstream to the shockwave adjacent part of the nozzle has a negative effect on the disparity of the aerosol. The following assay demonstrates how the shockwave is shifted downstream ba a shortened laval nozzle. As a result the dispersity of the aerosol is increased in the stationary as well as in the instationary gasflow

Plant growth forms dictate adaptations to the local climate

Adaptive radiation is a significant driver of biodiversity. Primarily studied in animal systems, mechanisms that trigger adaptive radiations remain poorly understood in plants. A frequently claimed indicator of adaptive radiation in plants is growth form diversity when tied to the occupation of different habitats. However, it remains obscure whether morphological adaptations manifest as growth form diversity per se or as its constituent traits. We use the classic Aeonium radiation from the Canary Islands to ask whether adaptation across climatic space is structured by growth form evolution. Using morphological sampling with site-associated climate in a phylogenetic context, we find that growth forms dictate adaptations to the local environment. Furthermore, we demonstrate that the response of specific traits to analogous environments is antagonistic when growth forms are different. This finding suggests for the first time that growth forms represent particular ecological functions, allowing the co-occurrence of closely related species, being a product of divergent selection during evolution in sympatry.info:eu-repo/semantics/publishedVersio

How challenging RADseq data turned out to favor coalescent-based species tree inference. A case study in Aichryson (Crassulaceae)

Analysing multiple genomic regions while incorporating detection and qualification of discordance among regions has become standard for understanding phylogenetic relationships. In plants, which usually have comparatively large genomes, this is feasible by the combination of reduced-representation library (RRL) methods and high-throughput sequencing enabling the cost effective acquisition of genomic data for thousands of loci from hundreds of samples. One popular RRL method is RADseq. A major disadvantage of established RADseq approaches is the rather short fragment and sequencing range, leading to loci of little individual phylogenetic information. This issue hampers the application of coalescent-based species tree inference. The modified RADseq protocol presented here targets ca. 5,000 loci of 300-600nt length, sequenced with the latest short-read-sequencing (SRS) technology, has the potential to overcome this drawback. To illustrate the advantages of this approach we use the study group Aichryson Webb & Berthelott (Crassulaceae), a plant genus that diversified on the Canary Islands. The data analysis approach used here aims at a careful quality control of the long loci dataset. It involves an informed selection of thresholds for accurate clustering, a thorough exploration of locus properties, such as locus length, coverage and variability, to identify potential biased data and a comparative phylogenetic inference of filtered datasets, accompanied by an evaluation of resulting BS support, gene and site concordance factor values, to improve overall resolution of the resulting phylogenetic trees. The final dataset contains variable loci with an average length of 373nt and facilitates species tree estimation using a coalescent-based summary approach. Additional improvements brought by the approach are critically discussed

Inter- and intra-island speciation and their morphological and ecological correlates in Aeonium (Crassulaceae), a species-rich Macaronesian radiation

Background and Aims The most species-rich and ecologically diverse plant radiation on the Canary Islands is the Aeonium alliance (Crassulaceae). In island radiations like this, speciation can take place either within islands or following dispersal between islands. Aiming at quantifying intra- and inter-island speciation events in the evolution of Aeonium, and exploring their consequences, we hypothesized that (1) intra-island diversification resulted in stronger ecological divergence of sister lineages, and that (2) taxa on islands with a longer history of habitation by Aeonium show stronger ecological differentiation and produce fewer natural hybrids. Methods We studied the biogeographical and ecological setting of diversification processes in Aeonium with a fully sampled and dated phylogeny inferred using a ddRADseq approach. Ancestral areas and biogeographical events were reconstructed in BioGeoBEARS. Eleven morphological characters and three habitat characteristics were taken into account to quantify the morphological and ecological divergence between sister lineages. A co-occurrence matrix of all Aeonium taxa is presented to assess the spatial separation of taxa on each island. Key Results We found intra- and inter-island diversification events in almost equal numbers. In lineages that diversified within single islands, morphological and ecological divergence was more pronounced than in lineages derived from inter-island diversification, but only the difference in morphological divergence was significant. Those islands with the longest history of habitation by Aeonium had the lowest percentages of co-occurring and hybridizing taxon pairs compared with islands where Aeonium arrived later. Conclusions Our findings illustrate the importance of both inter- and intra-island speciation, the latter of which is potentially sympatric speciation. Speciation on the same island entailed significantly higher levels of morphological divergence compared with inter-island speciation, but ecological divergence was not significantly different. Longer periods of shared island habitation resulted in the evolution of a higher degree of spatial separation and stronger reproductive barriers.info:eu-repo/semantics/publishedVersio

An optimized split-ubiquitin cDNA-library screening system to identify novel interactors of the human Frizzled 1 receptor

The yeast split-ubiquitin system has previously been shown to be suitable to detect protein interactions of membrane proteins and of transcription factors in vivo. Therefore, this technology complements the classical split-transcription factor based yeast two-hybrid system (Y2H). Success or failure of the Y2H depends primarily on the ability to avoid false-negative and false-positive hits that become a limiting factor for the value of the system, especially in large scale proteomic analyses. We provide here a systematic assessment of parameters to help improving the quality of split-ubiquitin cDNA-library screenings. We experimentally defined the optimal 5-fluoroorotic acid (5-FOA) concentration as a key parameter to increase the reproducibility of interactions and, at the same time, to keep non-specific background growth low. Furthermore, we show that the efficacy of the 5-FOA selection is modulated by the plating density of the yeast clones. Moreover, a reporter-specific class of false-positive hits was identified, and a simple phenotypic assay for efficient de-selection was developed. We demonstrate the application of this improved system to identify novel interacting proteins of the human Frizzled 1 receptor. We identified several novel interactors with components of the Wnt-Frizzled signalling pathways and discuss their potential roles as direct mediators of Frizzled receptor signalling. The present work is the first example of a split-ubiquitin interaction screen using an in-situ expressed receptor of the serpentine class, emphasizing the suitability of the described improvements in the screening protocol

Feedback between societal change and hydrological response in Wadi Natuf, a karstic mountainous watershed in the occupied Palestinian Westbank

Runoff observations with high spatial and temporal resolution before, during and since the Intifada in the occupied Palestinian West Bank, allow for new insights into the feedback between changing social systems and hydrological response under changing land forms. The lack of land control and infrastructure, movement restrictions and tight closure regimes, intensive settlement expansion and mushrooming unregulated solid waste dump-sites impact on runoff generation, groundwater recharge, flow patterns and rising water quality concerns. Long-term monitoring results from a 105 km2 Mediterranean climate catchment are presented. More research will strengthen these linkages. Changing socio-hydrological context of land sovereignty and equitable water rights remain paramount for addressing the chronic water crisis, establishing more symmetrical access and sustainable management of the shared water resources