BB-meson decay into a proton and dark antibaryon from QCD light-cone sum rules

The recently developed $B$-Mesogenesis scenario predicts decays of $B$ mesons into a baryon and hypothetical dark antibaryon $\Psi$. We suggest a method to calculate the amplitude of the simplest exclusive decay mode $B^+\to p \Psi$. Considering two models of $B$-Mesogenesis, we obtain the $B\to p$ hadronic matrix elements by applying QCD light-cone sum rules with the proton light-cone distribution amplitudes. We estimate the $B^+\to p \Psi$ decay width as a function of the mass and effective coupling of the dark antibaryon.Comment: Several comments added. Version to be published in Phys.Lett.

Non-Stationary Dark Energy Around a Black Hole

Numerical simulations of the accretion of test scalar fields with non-standard kinetic terms (of the k-essence type) onto a Schwarzschild black hole are performed. We find a full dynamical solution for the spherical accretion of a Dirac-Born-Infeld type scalar field. The simulations show that the accretion eventually settles down to a well known stationary solution. This particular analytical steady state solution maintains two separate horizons. The standard horizon is for the usual particles propagating with the limiting speed of light, while the other sonic horizon is for the k-essence perturbations propagating with the speed of sound around this accreting background. For the case where the k-essence perturbations propagate superluminally, we show that one can send signals from within a black hole during the approach to the stationary solution. We also find that a ghost condensate model settles down to a stationary solution during the accretion process.Comment: 8 pages, 10 figure

Incorporation of the Roadify API in Ride and Bike Sharing Systems

Ride and bike share companies have an interest in optimizing trips involving multi-modal transit. To make these services more user-friendly and efficient, we proposed that transit data should be integrated into them. Providing transit data to rideshare drivers in particular would increase their productivity and profits. To develop a plan for partnership between these companies and our sponsor, we developed pricing models and assessed how the APIs would work together. A tiered subscription model with a free trial base became the pricing structure of choice for a partnership with ridesharing company Uber, following research and discussions with our sponsor. Despite initial promise, we ruled out bike sharing as a possibility due to limited digital architecture and weaker financial incentives

Der prädiktive Wert präoperativer Receptor-activator-of-nuclear-factor-kappa-B-Ligand- und Osteoprotegerin-Serumkonzentrationen für das Wiederauftreten eines Prostatakarzinoms nach radikaler Prostatektomie

Eine Vielzahl von Studien zeigte bereits auf, dass der RANKL-RANK-OPG-Signalweg eine bedeutende Rolle in der Pathogenese des Prostatakarzinomes spielt. Die prognostische Wertigkeit der Serumkonzentrationen von RANKL und OPG für das Wiederauftreten eines Prostatakarzinomes nach radikaler Prostatektomie wurde allerdings bisher nicht ausreichend erforscht. Dies ist die erste Studie, welche die prognostische Wertigkeit von Serum-Proteinen des RANKL-RANK-OPG-Signalweges bei Patienten mit lokal begrenztem Prostatakarzinom untersucht. Es wurde retrospektiv ein Fünf-Jahres-Follow-Up einer Kohorte von 157 Patienten, die sich an der urologischen Universitätsklinik Tübingen einer Prostatektomie unterzogen hatten, erhoben und mit präoperativen Serum-Konzentrationen von sRANKL- und OPG verglichen. Eine erhöhte präoperative sRANKL-Konzentration und ein erhöhter präoperativer sRANKL-OPG-Quotient erwiesen sich als unabhängige Prädiktoren für das postoperativ vermehrte Auftreten eines biochemischen Rezidivs. Bei Patienten mit einer sRANKL-Serumkonzentration auf oder oberhalb des Medians war der Anteil derer, die nach fünf Jahren kein biochemisches Rezidiv erlitten 72%, und unterhalb des Medians 85% (Tab. 9; Abb. 10, p=0,02*). Bei Patienten mit einem sRANKL-OPG-Quotienten oberhalb des Medians war der Anteil derer, die in 5 Jahren kein biochemisches Rezidiv erlitten 70%, derer auf oder unterhalb des Medians 86% (Tab. 9; Abb. 12, p=0,029*). Ein sRANKL-OPG-Quotient oberhalb des Medians entspricht daher einem relativen Risiko von 2,12 bzw. einer Odds Ratio von 2,59. Eine verminderte OPG-Konzentration wies zwar auf ein erhöhtes Risiko für ein biochemisches Rezidiv hin, jedoch erwies sich dieser Trend nach statistischer Analyse als nicht signifikant. Es zeigte sich jedoch eine mit anderen Studien übereinstimmende, altersabhängige Steigerung der OPG-Serumkonzentration. Diese Daten lassen die Hypothese zu, dass ein therapeutisches Eingreifen in den RANKL-Signalweg zu einer verbesserten Krankheitsprognose für Prostatakarzinom-Patienten führen kann. Der Ursprung einer erhöhten sRANKL-Serumkonzentration bei Prostatakarzinompatienten - entweder aus Tumorzellen oder aus dem Knochenmark - bleibt weiterhin zu identifizieren

Piezoelectric titanium based microfluidic pump and valves for implantable medical applications

Medical devices often require precise movement of fluids. Automated implants with no need for manual handling improve patient care significantly. However, existing microfluidic devices do not fulfil the necessary specifications of size, safety, hermetic sealing, and artefact free medical imaging, as well as energy efficiency combined with adapted fluidic properties. In this work we designed, manufactured, and experimentally evaluated three piezoelectric microfluidic devices for implant automation: a diaphragm pump, a normally closed valve, and a normally open valve. All devices are made of titanium, minimizing the risk of artefacts in medical imaging. They have similar form factors and use the same actuation method. For the later, a specific mounting process of the piezo actuator enables outstanding fluidic performance during experimental evaluations. The titanium micropumps show a maximal flow of (14 ± 2.2) ml/min and pressure build-up of 75 kPa. The normally closed valve’s leakage rates are extremely low with less than 1 μL/min. Detailed investigations further include the actuator stroke, a lifetime study for normally open valves, and a numerical and experimental evaluation of the normally closed valve’s spring foil. The introduced titanium technology platform is ideally suited for system integration accounted for by the use of the same actuation principle and the similar form factor and a simple design. The development of small, smart, and energy efficient implants for improved treatment is possible based on the introduced platform

Isometry groups of non-positively curved spaces: structure theory

We develop the structure theory of full isometry groups of locally compact non-positively curved metric spaces. Amongst the discussed themes are de Rham decompositions, normal subgroup structure and characterising properties of symmetric spaces and Bruhat--Tits buildings. Applications to discrete groups and further developments on non-positively curved lattices are exposed in a companion paper: "Isometry groups of non-positively curved spaces: discrete subgroups".Comment: The original version (September 2, 2008) has been split into two articles. This is the first part; the second is available as of today on the arxiv under the title: "Isometry groups of non-positively curved spaces: discrete subgroups

Non-minimal monopoles of the Dirac type as realization of the censorship conjecture

We discuss a class of exact solutions of a three-parameter non-minimally extended Einstein-Maxwell model, which are attributed to non-minimal magnetic monopoles of the Dirac type. We focus on the investigation of the gravitational field of Dirac monopoles for those models, for which the singularity at the central point is hidden inside of an event horizon independently on the mass and charge of the object. We obtained the relationships between the non-minimal coupling constants, for which this requirement is satisfied. As explicit examples, we consider in detail two one-parameter models: first, non-minimally extended Reissner-Nordstr\"om model (for the magnetically charged monopole), second, the Drummond-Hathrell model.Comment: 9 pages; one reference added, accepted to Phys. Rev.

On T-Duality in Brane Gas Cosmology

In the context of homogeneous and isotropic superstring cosmology, the T-duality symmetry of string theory has been used to argue that for a background space-time described by dilaton gravity with strings as matter sources, the cosmological evolution of the Universe will be nonsingular. In this Letter we discuss how T-duality extends to brane gas cosmology, an approximation in which the background space-time is again described by dilaton gravity with a gas of branes as a matter source. We conclude that the arguments for nonsingular cosmological evolution remain valid.Comment: 8 pages, Appendix adde