Gauged Supergravity and Singular Calabi-Yau Manifolds

Compactifications of M-theory on singular manifolds contain additional charged massless states descending from M-branes wrapped on vanishing cycles. We construct the first explicit example of a complete supergravity Lagrangian that includes such extra states. This is done for a compactification on a Calabi-Yau threefold that develops a genus zero curve of A_1 singularities at the boundary of the K\"ahler cone with a resulting SU(2) gauge symmetry enhancement. The corresponding SU(2) gauged supergravity Lagrangian includes two charged and two neutral vector multiplets, and turns out to be uniquely fixed by the Calabi-Yau geometry and by the effective ungauged Lagrangian describing the Coulomb branch. One can see explicitly how resolving the singularity corresponds to a supersymmetric Higgs effect in the gauged supergravity description. The elementary transformation relating the two families of smooth Calabi-Yau resolutions of the singularity acts as the SU(2) Weyl twist. The resulting structure appears to be very rigid and is likely to apply to other types of singularities and manifolds as well.Comment: 37 pages, no figures, JHEP3, minor typos corrected, one reference added, Appendix A streamline

Laryngoscopic Image Stitching for View Enhancement and Documentation - First Experiences

One known problem within laryngoscopy is the spatially limited view onto the hypopharynx and the larynx through the endoscope. To examine the complete larynx and hypopharynx, the laryngoscope can be rotated about its main axis, and hence the physician obtains a complete view. If such examinations are captured using endoscopic video, the examination can be reviewed in detail at a later time. Nevertheless, in order to document the examination with a single representative image, a panorama image can be computed for archiving and enhanced documentation. Twenty patients with various clinical findings were examined with a 70 rigid laryngoscope, and the video sequences were digitally stored. The image sequence for each patient was then post-processed using an image stitching tool based on SIFT features, the RANSAC approach and blending. As a result, endoscopic panorama images of the larynx and pharynx were obtained for each video sequence. The proposed approach of image stitching for laryngoscopic video sequences offers a new tool for enhanced visual examination and documentation of morphologic characteristics of the larynx and the hypopharynx

Diels-Alder reaction of α-phellandrene and p-benzoquinone as an experiment for the organic chemistry teaching lab

https://openriver.winona.edu/urc2018/1130/thumbnail.jp

Porous crystals in charged sphere suspensions by aggregate-driven phase separation

The kinetics of phase transition processes often governs the resulting material microstruc-ture. Using optical microscopy, we here investigate the formation and stabilization of a po-rous crystalline microstructure forming in low-salt suspensions of charged colloidal spheres containing aggregates comprising some 5-10 of these colloids. We observe the transformation of an initially crystalline colloidal solid with homogeneously incorporated aggregates to indi-vidual, compositionally refined crystallites of perforated morphology coexisting with an ag-gregate-enriched fluid phase filling the holes and separating individual crystallites. A prelimi-nary kinetic characterization suggests that the involved processes follow power laws. We show that this route to porous materials is neither restricted to nominally single component systems nor to a particular microstructure to start from. However, it necessitates an early rapid solidification stage during which the aggregates become trapped in the bulk of the host-crystals. The thermodynamic stability of the reconstructed crystalline scaffold against melt-ing under increased salinity was found comparable to that of pure phase crystallites grown very slowly from a melt. Future implications of this novel route to porous colloidal crystals are discussed.Comment: regular original article, 24 p. 8 Figs, ES

The tax-inducible actin-bundling protein fascin is crucial for release and cell-to-cell transmission of human T-cell leukemia virus type 1 (HTLV-1)

The delta-retrovirus Human T-cell leukemia virus type 1 (HTLV-1) preferentially infects CD4(+) T-cells via cell-to-cell transmission. Viruses are transmitted by polarized budding and by transfer of viral biofilms at the virological synapse (VS). Formation of the VS requires the viral Tax protein and polarization of the host cytoskeleton, however, molecular mechanisms of HTLV-1 cell-to-cell transmission remain incompletely understood. Recently, we could show Tax-dependent upregulation of the actin-bundling protein Fascin (FSCN-1) in HTLV-1-infected T-cells. Here, we report that Fascin contributes to HTLV-1 transmission. Using single-cycle replication-dependent HTLV-1 reporter vectors, we found that repression of endogenous Fascin by short hairpin RNAs and by Fascin-specific nanobodies impaired gag p19 release and cell-to-cell transmission in 293T cells. In Jurkat T-cells, Tax-induced Fascin expression enhanced virus release and Fascin-dependently augmented cell-to-cell transmission to Raji/CD4(+) B-cells. Repression of Fascin in HTLV-1-infected T-cells diminished virus release and gag p19 transfer to co-cultured T-cells. Spotting the mechanism, flow cytometry and automatic image analysis showed that Tax-induced T-cell conjugate formation occurred Fascin-independently. However, adhesion of HTLV-1-infected MT-2 cells in co-culture with Jurkat T-cells was reduced upon knockdown of Fascin, suggesting that Fascin contributes to dissemination of infected T-cells. Imaging of chronically infected MS9 T-cells in co-culture with Jurkat T-cells revealed that Fascin's localization at tight cell-cell contacts is accompanied by gag polarization suggesting that Fascin directly affects the distribution of gag to budding sites, and therefore, indirectly viral transmission. In detail, we found gag clusters that are interspersed with Fascin clusters, suggesting that Fascin makes room for gag in viral biofilms. Moreover, we observed short, Fascin-containing membrane extensions surrounding gag clusters and clutching uninfected T-cells. Finally, we detected Fascin and gag in long-distance cellular protrusions. Taken together, we show for the first time that HTLV-1 usurps the host cell factor Fascin to foster virus release and cell-to-cell transmission

Cost-effective 3D scanning and printing technologies for outer ear reconstruction: Current status

Current 3D scanning and printing technologies offer not only state-of-the-art developments in the field of medical imaging and bio-engineering, but also cost and time effective solutions for surgical reconstruction procedures. Besides tissue engineering, where living cells are used, bio-compatible polymers or synthetic resin can be applied. The combination of 3D handheld scanning devices or volumetric imaging, (open-source) image processing packages, and 3D printers form a complete workflow chain that is capable of effective rapid prototyping of outer ear replicas. This paper reviews current possibilities and latest use cases for 3D-scanning, data processing and printing of outer ear replicas with a focus on low-cost solutions for rehabilitation engineering

Reputation als Steuerungsinstrument in netzwerkinternen Märkten

In der wirtschaftswissenschaftlichen Literatur, vor allem in der Literatur zur Spieltheorie, lassen sich zahlreiche Beiträge identifizieren, die sich mit der Bedeutung von Reputation als Instrument zur Reduzierung von Qualitätsunsicherheit bei Transaktionen auf Märkten auseinandersetzen (Celentani/Pesendorfer 1996; Shapiro 1983). Auch für elektronische Märkte und Online-Gemeinschaften wurde die Relevanz von Reputationsmechanismen erkannt und in der Literatur diskutiert (Koch et al. 2000; Standifird 2002). Während die Forschungsarbeiten zur Wirkungsweise von Reputation auf herkömmlichen Märkten bereits zu differenzierten Aussagen geführt haben, existieren derartige Arbeiten bezogen auf interne Märkte bisher nicht. Interne Märkte lassen sich als spezifische Anbieter-Nachfrager-Beziehung innerhalb einer Organisationseinheit beschreiben, im Rahmen derer Leistungen über den Preis als zentralen Koordinationsmechanismus ausgetauscht werden. In hierarchischen Organisationen werden interne Märkte vorwiegend in Profit-Center-Strukturen etabliert. Auch in Unternehmensnetzwerken lassen sich interne Märkte realisieren, wenn die Partnerunternehmen eine interne Konkurrenz im Netzwerk zulassen. In diesem Fall wird bei Vorliegen einer Kundenanfrage eine netzwerkinterne Ausschreibung angestoßen, bei der verschiedene Partnerunternehmen mit auftragsspezifischer Kompetenz um die Vergabe von Teilleistungen konkurrieren. Das zentrale Entscheidungskriterium für die Vergabe der Teilleistungen ist in der Regel der von den Partnerunternehmen abgegebene Angebotspreis. Neben dem Preis ist bei der Entscheidung aber auch die Reputation eines Partnerunternehmens von Bedeutung. Eine gute Reputation kann eine ex-ante bestehende Qualitätsunsicherheit über die Leistungsqualität eines Partnerunternehmens reduzieren und somit die Entscheidung über die Auftragsvergabe beeinflussen. Ein Reputationsmechanismus kann auf diese Weise die Auswahl geeigneter Partnerunternehmen erleichtern. Es lässt sich weiterhin zeigen, dass ein funktionierender Reputationsmechanismus zusätzlich zur Lieferung guter Qualität im Netzwerk diszipliniert. Das Ziel dieses Beitrags ist es, die skizzierten Mechanismen in netzwerkinternen Märkten darzustellen und deren ökonomischen Implikationen herauszuarbeiten

Using simulated fluorescence cell micrographs for the evaluation of cell image segmentation algorithms

The zip archive contains real images showing macrophages. (ZIP 28979 kb

Towards a New Science of a Clinical Data Intelligence

In this paper we define Clinical Data Intelligence as the analysis of data generated in the clinical routine with the goal of improving patient care. We define a science of a Clinical Data Intelligence as a data analysis that permits the derivation of scientific, i.e., generalizable and reliable results. We argue that a science of a Clinical Data Intelligence is sensible in the context of a Big Data analysis, i.e., with data from many patients and with complete patient information. We discuss that Clinical Data Intelligence requires the joint efforts of knowledge engineering, information extraction (from textual and other unstructured data), and statistics and statistical machine learning. We describe some of our main results as conjectures and relate them to a recently funded research project involving two major German university hospitals.Comment: NIPS 2013 Workshop: Machine Learning for Clinical Data Analysis and Healthcare, 201