Localization for mobile robots using panoramic vision, local features and particle filter

In this paper we present a vision-based approach to self-localization that uses a novel scheme to integrate feature-based matching of panoramic images with Monte Carlo localization. A specially modified version of Lowe’s SIFT algorithm is used to match features extracted from local interest points in the image, rather than using global features calculated from the whole image. Experiments conducted in a large, populated indoor environment (up to 5 persons visible) over a period of several months demonstrate the robustness of the approach, including kidnapping and occlusion of up to 90% of the robot’s field of view

Stock Exchanges and Issuers: A Changing Relationship

The nature of the relation between stock exchanges and firms seeking a listing has changed considerably over the past decades. In this paper, we argue that the relationship has lost most of its historic complexity and has almost been reduced to a standardized contract in the sense that there are few contractual properties distinguishing listing on different exchanges apart from granting access to a specific liquidity pool. Analyzing the actual specifications of listing agreements at five major stock exchanges, we demonstrate that the contractual features are converging towards a standardized agreement. Furthermore, we show that some of the functions formerly fulfilled by exchanges are now performed by other institutions. We analyze whether these changes are reflected by policy makers in their efforts to create integrated European capital markets.Die Beziehung zwischen Börsen und Eigenkapitalemittenten hat sich in den vergangenen Jahrzehnten fundamental verändert. In diesem Beitrag argumentieren wir, dass diese Beziehung einer standardisierten Vertragsbeziehung gleicht, die ihre historische Komplexität weitgehend verloren hat. Während Börsen in der Vergangenheit unterschiedlich gestaltete Listinganforderungen an Unternehmen gestellt und durchgesetzt haben, ist heute ihr wesentliches Differenzierungsmerkmal die Liquidität der gehandelten Aktien. Eine Untersuchung der Listinganforderungen von fünf bedeutenden Börsen zeigt, dass die wichtigsten Vertragsbestandteile des Abkommens zwischen Emmittent und Börse weitgehend vereinheitlicht sind. Wir zeigen weiterhin, dass neue Institutionen wie etwa nationale Börsenaufsichtsbehörden einige der früher von Börsen wahrgenommenen Aufgaben übernommen haben. Abschließend untersuchen wir, ob und in welchem Maße diese Veränderungen in den gegenwärtigen Bemühungen zur Schaffung integrierter europäischer Kapitalmärkte berücksichtigt werden

Conformational Changes and Slow Dynamics through Microsecond Polarized Atomistic Molecular Simulation of an Integral Kv1.2 Ion Channel

Structure and dynamics of voltage-gated ion channels, in particular the motion of the S4 helix, is a highly interesting and hotly debated topic in current membrane protein research. It has critical implications for insertion and stabilization of membrane proteins as well as for finding how transitions occur in membrane proteins—not to mention numerous applications in drug design. Here, we present a full 1 µs atomic-detail molecular dynamics simulation of an integral Kv1.2 ion channel, comprising 120,000 atoms. By applying 0.052 V/nm of hyperpolarization, we observe structural rearrangements, including up to 120° rotation of the S4 segment, changes in hydrogen-bonding patterns, but only low amounts of translation. A smaller rotation (∼35°) of the extracellular end of all S4 segments is present also in a reference 0.5 µs simulation without applied field, which indicates that the crystal structure might be slightly different from the natural state of the voltage sensor. The conformation change upon hyperpolarization is closely coupled to an increase in 310 helix contents in S4, starting from the intracellular side. This could support a model for transition from the crystal structure where the hyperpolarization destabilizes S4–lipid hydrogen bonds, which leads to the helix rotating to keep the arginine side chains away from the hydrophobic phase, and the driving force for final relaxation by downward translation is partly entropic, which would explain the slow process. The coordinates of the transmembrane part of the simulated channel actually stay closer to the recently determined higher-resolution Kv1.2 chimera channel than the starting structure for the entire second half of the simulation (0.5–1 µs). Together with lipids binding in matching positions and significant thinning of the membrane also observed in experiments, this provides additional support for the predictive power of microsecond-scale membrane protein simulations

Pain Behavior Changes Following Disc Puncture Relate to Nucleus Pulposus Rather than to the Disc Injury Per Se: An Experimental Study in Rats

It has previously been demonstrated that disc puncture in the rat induced changes in grooming and wet dog shakes, two behavioral changes that may be linked to discomfort and neuropathic pain. In this study the aim was to separate the effects of disc injury and the epidural presence of nucleus pulposus. Following anesthesia, the L4-5 disc was exposed using a dorsal approach. Ten rats received a superficial disc injury without nucleus pulposus leakage and ten rats received nucleus pulposus from a donor rat without disc injury. In ten animals the L4-5 disc was punctured using a ventral approach, with 10 corresponding controls. Spontaneous behavior was assessed after surgery. The data was matched to historical control of dorsal sham surgery and disc puncture. The study showed that the effects of nucleus pulposus were more pronounced than the effects induced by the disc injury. Ventral disc puncture did not induce any behavioral changes different from sham exposure. In conclusion, the data from the study indicate that behavioral changes induced by disc puncture are more likely to relate to the epidural presence of nucleus pulposus than the disc injury per se

Test stand for the Silicon Vertex Detector of the Collider Detector Facility

A test stand for the next generation of the Silicon Vertex Detector (SVX-II) of the Collider Detector Facility (CDF) at Fermilab has been developed. It is capable of performing cosmic ray, beam, and laser pulsing tests on silicon strip detectors using the new generation of SVX chips. The test stand is composed of a SGI workstation, a VME CPU, the Silicon Test Acquisition and Readout (STAR) board, the Test Fiber Interface Board (TFIB), and the Test Port Card (TPC). The STAR mediates between external stimuli for the different tests and produces appropriate high level commands which are sent to the TFIB. The TFIB, in conjunction with the TPC, translates these commands into the correct logic levels to control the SVX chips. The four modes of operation of the SVX chips are configuration, data acquisition, digitization, and data readout. The data read out from the SVX chips is transferred to the STAR. The STAR can then be accessed by the VME CPU and the SGI workstation for future analyses. The detailed description of this test stand is given

Discovery of an Auto-Regulation Mechanism for the Maltose ABC Transporter MalFGK2

The maltose transporter MalFGK2, together with the substrate-binding protein MalE, is one of the best-characterized ABC transporters. In the conventional model, MalE captures maltose in the periplasm and delivers the sugar to the transporter. Here, using nanodiscs and proteoliposomes, we instead find that MalE is bound with high-affinity to MalFGK2 to facilitate the acquisition of the sugar. When the maltose concentration exceeds the transport capacity, MalE captures maltose and dissociates from the transporter. This mechanism explains why the transport rate is high when MalE has low affinity for maltose, and low when MalE has high affinity for maltose. Transporter-bound MalE facilitates the acquisition of the sugar at low concentrations, but also captures and dissociates from the transporter past a threshold maltose concentration. In vivo, this maltose-forced dissociation limits the rate of transport. Given the conservation of the substrate-binding proteins, this mode of allosteric regulation may be universal to ABC importers