The algebraic theory of tempered representations of p-adic groups I. Parabolic induction and restriction

This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.In this paper we study the category of non-degenerate modules over the Harish-Chandra Schwartz algebra of a p-adic connected reductive group. We construct functors of parabolic induction and restriction and show that they are exact and both ways adjoint to each other.Peer Reviewe

Cauchy-perturbative matching revisited: tests in spherical symmetry

During the last few years progress has been made on several fronts making it possible to revisit Cauchy-perturbative matching (CPM) in numerical relativity in a more robust and accurate way. This paper is the first in a series where we plan to analyze CPM in the light of these new results. Here we start by testing high-order summation-by-parts operators, penalty boundaries and contraint-preserving boundary conditions applied to CPM in a setting that is simple enough to study all the ingredients in great detail: Einstein's equations in spherical symmetry, describing a black hole coupled to a massless scalar field. We show that with the techniques described above, the errors introduced by Cauchy-perturbative matching are very small, and that very long term and accurate CPM evolutions can be achieved. Our tests include the accretion and ring-down phase of a Schwarzschild black hole with CPM, where we find that the discrete evolution introduces, with a low spatial resolution of \Delta r = M/10, an error of 0.3% after an evolution time of 1,000,000 M. For a black hole of solar mass, this corresponds to approximately 5 s, and is therefore at the lower end of timescales discussed e.g. in the collapsar model of gamma-ray burst engines. (abridged)Comment: 14 pages, 20 figure

Zusammensetzung polarer stratosphärischer Wolkenteilchen simuliert in einer Aerosolkammer

In einer Aerosolkammer können Teilchenänderungen unter kontrollierten Bedingungen untersucht werden. Dies ermöglicht ein besseres Verständnis für den Bildungsprozeß polarer stratosphärischer Wolkenteilchen, die für den Ozonabbau wichtig sind. Hierfür wurde ein Aerosolstrahl-Massenspektrometer entwickelt, um die Zusammensetzung der Wolkenteilchen in der Kammer zu messen. Die Teilchen werden von der Umgebungsluft durch eine aerodynamische Linse und ein differentiell gepumptes Vakuumsystem getrennt. Nach anschließendem Verdampfen wird das entstehende Gas massenspektrometrisch untersucht. Das Instrument besitzt eine hohe Empfindlichkeit. Dies ist nötig, um trotz abnehmender Aerosolmenge in der Kammer lange Beobachtungszeiten zu gewährleisten. Die Zusammensetzung der Teilchen wurde für flüssige binäre H2SO4/H2O- und ternäre HNO3/H2SO4/H2O-Teilchen über Tage hinweg gemessen. Währenddessen wurden die Konzentrationen in der Gasphase und die Temperaturen im Bereich von 185 bis 230 K variiert. Durch diese Experimente konnte die Gültigkeit von Modellrechnungen für niedrigere Temperaturen bestätigt werden, als bisher untersucht wurden. Trotz langer Beobachtungszeiten bei Übersättigungen gegenüber festen Hydraten blieben die Teilchen flüssig. Auch bei Eisübersättigungen größer als 1,4 kam es nicht zu Phasenübergängen. Die Bildung fester Teilchen war nur durch die schnelle Zugabe von HNO3- und H2O-Gas möglich. In diesem Experiment wurde die Koexistenz von Eis und Salpetersäuretrihydrat unter Bedingungen der polaren Stratosphäre beobachtet

Ultrasound-Assisted CO2 Flooding to Improve Oil Recovery

The authors would like to gratefully acknowledge and appreciate the School of Engineering, University of Aberdeen, Aberdeen, Scotland, United Kingdom, for the provision of the laboratory facilities necessary for completing this work.Peer reviewedPostprin

Vasodilator-Stimulated Phosphoprotein (VASP)-dependent and -independent pathways regulate thrombin-induced activation of Rap1b in platelets

BACKGROUND: Vasodilator-Stimulated Phosphoprotein (VASP) is involved in the inhibition of agonist-induced platelet aggregation by cyclic nucleotides and the adhesion of platelets to the vascular wall. α(IIb)β(3) is the main integrin responsible for platelet activation and Rap1b plays a key role in integrin signalling. We investigated whether VASP is involved in the regulation of Rap1b in platelets since VASP-null platelets exhibit augmented adhesion to endothelial cells in vivo. METHODS: Washed platelets from wild type and VASP-deficient mice were stimulated with thrombin, the purinergic receptors agonist ADP, or the thromboxane A2 receptor agonist U46619 and Rap1b activation was measured using the GST-RalGDS-RBD binding assay. Interaction of VASP and Crkl was investigated by co-immunoprecipitation, confocal microscopy, and pull-down assays using Crkl domains expressed as GST-fusion proteins. RESULTS: Surprisingly, we found that activation of Rap1b in response to thrombin, ADP, or U46619 was significantly reduced in platelets from VASP-null mice compared to platelets from wild type mice. However, inhibition of thrombin-induced activation of Rap1b by nitric oxide (NO) was similar in platelets from wild type and VASP-null mice indicating that the NO/cGMP/PKG pathway controls inhibition of Rap1b independently from VASP. To understand how VASP regulated Rap1b, we investigated association between VASP and the Crk-like protein (Crkl), an adapter protein which activates the Rap1b guanine nucleotide exchange factor C3G. We demonstrated the formation of a Crkl/VASP complex by showing that: 1) Crkl co-immunoprecipitated VASP from platelet lysates; 2) Crkl and VASP dynamically co-localized at actin-rich protrusions reminiscent of focal adhesions, filopodia, and lamellipodia upon platelet spreading on fibronectin; 3) recombinant VASP bound directly to the N-terminal SH3 domain of Crkl; 4) Protein Kinase A (PKA) -mediated VASP phosphorylation on Ser157 abrogated the binding of Crkl. CONCLUSIONS: We identified Crkl as a novel protein interacting with VASP in platelets. We propose that the C3G/Crkl/VASP complex plays a role in the regulation of Rap1b and this explains, at least in part, the reduced agonist-induced activation of Rap1b in VASP-null platelets. In addition, the fact that PKA-dependent VASP phosphorylation abrogated its interaction with Crkl may provide, at least in part, a rationale for the PKA-dependent inhibition of Rap1b and platelet aggregation

Earth Observing-1 Spacecraft Bus

The Earth Observing 1 (EO-1) spacecraft is one of the most trouble-free spacecraft that NASA has launched in the last ten years. A NASA New Millennium Program (NMP) mission dedicated to validating revolutionary technologies that will be used in future government and commercial missions, EO-1 was launched in November 2000 and flies in formation with Landsat 7. As the prime contractor, Swales Aerospace designed and built the spacecraft bus, integrated and tested the EO-1 observatory, and performed launch-site operations. Developed under the faster-better-cheaper philosophy, EO-1 is an example of a successful low-cost mission. We describe the mission, its new technologies, the results of on-orbit evaluation and the keys to EO-1 success, from early design to final testing