Existence of the D0-D4 Bound State: a detailed Proof

We consider the supersymmetric quantum mechanical system which is obtained by dimensionally reducing d=6, N=1 supersymmetric gauge theory with gauge group U(1) and a single charged hypermultiplet. Using the deformation method and ideas introduced by Porrati and Rozenberg, we present a detailed proof of the existence of a normalizable ground state for this system

Absence of Ground States for a Class of Translation Invariant Models of Non-relativistic QED

We consider a class of translation invariant models of non-relativistic QED with net charge. Under certain natural assumptions we prove that ground states do not exist in the Fock space

Bifurcations, Chaos, Controlling and Synchronization of Certain Nonlinear Oscillators

In this set of lectures, we review briefly some of the recent developments in the study of the chaotic dynamics of nonlinear oscillators, particularly of damped and driven type. By taking a representative set of examples such as the Duffing, Bonhoeffer-van der Pol and MLC circuit oscillators, we briefly explain the various bifurcations and chaos phenomena associated with these systems. We use numerical and analytical as well as analogue simulation methods to study these systems. Then we point out how controlling of chaotic motions can be effected by algorithmic procedures requiring minimal perturbations. Finally we briefly discuss how synchronization of identically evolving chaotic systems can be achieved and how they can be used in secure communications.Comment: 31 pages (24 figures) LaTeX. To appear Springer Lecture Notes in Physics Please Lakshmanan for figures (e-mail: [email protected]

Analyticity of The Ground State Energy For Massless Nelson Models

We show that the ground state energy of the translationally invariant Nelson model, describing a particle coupled to a relativistic field of massless bosons, is an analytic function of the coupling constant and the total momentum. We derive an explicit expression for the ground state energy which is used to determine the effective mass.Comment: 33 pages, 1 figure, added a section on the calculation of the effective mas

Full-commanding a network: The dictator

A network of chaotic dynamical systems may synchronize. For some networks there is the possibility that, coupling a new node to the network, the synchronization will be commanded by that new node. That possibility depends on the network and on the way the new node is coupled to the network.We consider a coupling that can provide what we call a full-commanding and we define the corresponding full-commandwindow. The limit situations corresponding to a completely connected network and to a completely disconnected one provide us some understanding about what makes a network more receptive or more resistant to commanding

1.000.000 Fußballfans in einer Stadt mit 120.000 Einwohnern - ein notfallmedizinischer Albtraum?: Die Euro 2008 und das "Oranje-Wunder von Bern"

Zusammenfassung: Die Fußballeuropameisterschaft 2008 war die größte je in der Schweiz organisierte Sportveranstaltung. Eine Million Fußballfans besuchten in diesem Zeitraum Bern, und der lokale Flughafen Bern/Belp verzeichnete 261 zusätzliche Flüge. Pro Fußballspiel waren 33.000 Zuschauer im Stadion und 100.000 schauten in den Public-viewing-Zonen zu. Der Rettungsdienst und das Notfallzentrum des Inselspitals am Universitätsklinikum Bern waren für die medizinische Grundversorgung und die Notfallversorgung zuständig. Verletzungen und Krankheiten wurden mit einem standardisierten Score (NACA-Score, NACA National Advisory Committee of Aeronautics) analysiert. Details zu den Vorbereitungen, Kosten und Patientenzahlen werden im vorliegenden Artikel dargestellt. Insgesamt waren 30 zusätzlich Ambulanzfahrzeuge im Einsatz, 4723 zusätzliche Arbeitstage (1/3 davon durch medizinische Fachkräfte) wurden geleistet, 662 Ambulanzrufe gingen ein, 240 Personen benötigten eine medizinische Versorgung (62% Schweizer, 28% Niederländer, 10% anderer Nationalität). Von diesen wurden 51 Personen in einem der 4 städtischen Krankenhäuser behandelt. Es kamen keine Verletzungen der Grade NACAVI und VII vor (NACAI 4, NACAII 17, NACAIII 16, NACAIV 10, NACAV 4Patienten). Die Stadt Bern erstattete dem Inselspital 112.603EUR für die medizinische Versorgung. Die größten Anteile daran hatten die Sicherheitsmaßnahmen (50.300EUR) und die Kosten für medizinisches Personal (22.600EUR für Ärzte, 29.000EUR für Pflegefachkräfte). Aufgrund des schlechten Wetters und des vorbildlichen Verhaltens der Fans nahmen die Ereignisse einen eher friedlichen Verlau

Absence of Embedded Mass Shells: Cerenkov Radiation and Quantum Friction

We show that, in a model where a non-relativistic particle is coupled to a quantized relativistic scalar Bose field, the embedded mass shell of the particle dissolves in the continuum when the interaction is turned on, provided the coupling constant is sufficiently small. More precisely, under the assumption that the fiber eigenvectors corresponding to the putative mass shell are differentiable as functions of the total momentum of the system, we show that a mass shell could exist only at a strictly positive distance from the unperturbed embedded mass shell near the boundary of the energy-momentum spectrum.Comment: Revised version: a remark added at the end of Section

In vitro production of bovine embryos derived from individual donors in the Corral® dish

Background: Since the identity of the embryo is of outmost importance during commercial in vitro embryo production, bovine oocytes and embryos have to be cultured strictly per donor. Due to the rather low yield of oocytes collected after ovum pick-up (OPU) per individual cow, oocyte maturation and embryo culture take place in small groups, which is often associated with inferior embryo development. The objective of this study was to improve embryonic development in small donor groups by using the Corral (R) dish. This commercial dish is designed for human embryo production. It contains two central wells that are divided into quadrants by a semi-permeable wall. In human embryo culture, one embryo is placed per quadrant, allowing individual follow-up while embryos are exposed to a common medium. In our study, small groups of oocytes and subsequently embryos of different bovine donors were placed in the Corral (R) dish, each donor group in a separate quadrant. Results: In two experiments, the Corral (R) dish was evaluated during in vitro maturation (IVM) and/or in vitro culture (IVC) by grouping oocytes and embryos of individual bovine donors per quadrant. At day 7, a significantly higher blastocyst rate was noted in the Corral (R) dish used during IVM and IVC than when only used during IVM (12.9% +/- 2.10 versus 22.8% +/- 2.67) (P < 0.05). However, no significant differences in blastocyst yield were observed anymore between treatment groups at day 8 post insemination. Conclusions: In the present study, the Corral (R) dish was used for in vitro embryo production (IVP) in cattle; allowing to allocate oocytes and/or embryos per donor. As fresh embryo transfers on day 7 have higher pregnancy outcomes, the Corral (R) dish offers an added value for commercial OPU/IVP, since a higher blastocyst development at day 7 is obtained when the Corral (R) dish is used during IVM and IVC

Factors influencing brightness and beam quality of conventional and distributed Bragg reflector tapered laser diodes in absence of self-heating

In this study, the authors examine some of the factors affecting the brightness and the beam quality of high-power tapered lasers. The large volume resonators required to achieve a high-power, high-brightness operation make the beam quality sensitive to carrier lensing and a multimode operation. These cause bleaching of the regions outside the ridge waveguide. The beam quality in the conventional and the distributed Bragg reflector tapered lasers is examined in the absence of the self-heating effects to investigate the effect of the carrier lensing effects. The influence of the front facet reflectivity and the taper angle on the beam quality is investigated. The beam quality was found to degrade with an increase in the front facet reflectivity and for the larger taper angles in the conventional tapered lasers, especially at low ridge waveguide currents. Finally, the performance of the conventional tapered lasers employing a beamspoiler was assessed. The beam quality was found to be comparable with that achieved in the DBR tapered lasers