Computer Assisted Proof of Transverse Saddle-to-Saddle Connecting Orbits for First Order Vector Fields

In this paper we introduce a computational method for proving the existence of generic saddle-to-saddle connections between equilibria of first order vector fields. The first step consists of rigorously computing high order parametrizations of the local stable and unstable manifolds. If the local manifolds intersect, the Newton–Kantorovich theorem is applied to validate the existence of a so-called short connecting orbit. If the local manifolds do not intersect, a boundary value problem with boundary values in the local manifolds is rigorously solved by a contraction mapping argument on a ball centered at the numerical solution, yielding the existence of a so-called long connecting orbit. In both cases our argument yields transversality of the corresponding intersection of the manifolds. The method is applied to the Lorenz equations, where a study of a pitchfork bifurcation with saddle-to-saddle stability is done and where several proofs of existence of short and long connections are obtained.     

The effective potential of the confinement order parameter in the Hamiltonian approach

The effective potential of the order parameter for confinement is calculated within the Hamiltonian approach by compactifying one spatial dimension and using a background gauge fixing. Neglecting the ghost and using the perturbative gluon energy one recovers the Weiss potential. From the full non-perturbative potential calculated within a variational approach a critical temperature of the deconfinement phase transition of 269 MeV is found for the gauge group SU(2).     

Type II GaSb/GaAs quantum dot/ring stacks with extended photoresponse for efficient solar cells

We report on the fabrication of GaAs based p–i–n solar cells containing 5 and 10 layers of type II GaSb quantum rings grown by molecular beam epitaxy. Solar cells containing quantum rings show improved efficiency at longer wavelengths into the near-IR extending up to 1500 nm and show enhanced short-circuit current under 1 sun illumination compared to a GaAs control cell. A reduction in the open-circuit voltage is observed due to the build-up of internal strain. The MBE growth, formation and photoluminescence of single and stacked layers of GaSb/GaAs quantum rings are also presented.     

Laryngeal Myasthenia Gravis: Report of 40 Cases

Myasthenia gravis, an autoimmune disorder of the neuromuscular junction, is usually recognized because of ocular complaints or generalized weakness. We report a series of 40 patients who presented with dysphonia as their initial and primary complaint. Diagnostic testing included strobovideolaryngoscopy, electromyography (EMG) with repetitive stimulation and Tensilon testing, and laboratory and radiographic evaluation. Strobovideolaryngoscopy most commonly revealed fluctuating impairment of vocal fold mobility, either unilateral or bilateral. EMG detected evidence of neuromuscular junction abnormalities in all patients. Only one patient had evidence of antiacetylcholine receptor (ACh-R) antibodies, but many other abnormalities suggestive of autoimmune dysfunction were present. Pyridostigmine therapy was initiated in 34 patients but was not tolerated in 4. Of the remaining 30 patients, 23 reported improvement of symptoms. We conclude that myasthenia gravis can present with symptoms confined primarily to the larynx and should be included in the differential diagnosis of dysphonia.     

Auf einige Schattenseiten beim Gebrauch des denaturirten Spiritus zum Brennen

Ohne Zusammenfassung     

Autologous fat implantation for vocal fold scar: A preliminary report

New insights into the anatomy and physiology of phonation, along with technological advances in voice assessment and quantification, have led to dramatic improvements in medical voice care. Techniques to prevent vocal fold scar have been among the most important, especially scarring and hoarseness associated with voice surgery. Nevertheless, dysphonia due to vocal fold scar is still encountered all too frequently. Although it is not generally possible to restore such injured voices to normal, patients with scar-induced dysphonia can usually be helped. Voice improvement is optimized through a team approach. Treatment may include sophisticated voice therapy and vocal fold surgery. Although experience with collagen injection has been encouraging in selected cases (particularly in those involving limited areas of vocal fold scar), there is no consistently successful surgical technique. Attempts to treat massive vocal fold scar, such as may be seen following vocal fold stripping, have been particularly unsuccessful. This paper reports preliminary experience with the implantation of autologous fat into the vibratory margin of the vocal fold of patients with severe, extensive scarring. Using this technique, it appears possible to recreate a mucosal wave and improve voice quality. Additional research is needed.     

Electromagnetic probes of nuclear collisions at intermediate energy

We show that emission of high-energy electrons and photons in nuclear collisions at intermediate energies is sensitive to the space-time evolution of the reaction. The electron and photon spectra measure related but complementary quantities connected with the nuclear charge distribution. We show that at 60 MeV/u beam energy production of 50 MeV electrons is predicted to measurable probability.     

Evidence for a two-phonon octupole vibrational state in208Pb

Collective properties of^206,208Pb have been investigated with gamma-ray spectroscopy using nuclear and electromagnetic excitation by²⁰⁸Pb projectiles. From the measurement of particle-particle- and particle-particle- coincidences a new energy level in²⁰⁸Pb at 5.683 MeV was observed and the data suggest an interpretation as a 2-phonon octupole vibrational state with spin 4⁺ or 6⁺. For this state one finds the same dynamical deformation parameter ₃ as for the first-excited collective 3^– state. The results are compared to predictions of models which consider, in particular, the aspects of the quadrupole interaction and the interaction of the 2-particle pairing vibration with the 2-phonon octupole vibration. For the²⁰⁶Pb+²⁰⁸Pb system at 6.2 MeV/u the nuclear potential could be determined from the measured inelastic cross sections.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday     

Third-Order Optical Nonlinearity Studies of p-Heptaphenyl Derivatives-Doped Sol-Gel Processed Composite Glass and THF Solution by Degenerate Four-Wave Mixing and Optical Kerr Gate Measurements

We have investigated the nonlinear optical performance of new UV photostable dyes, didecyl and didecyloxy substitutedpara-polyphenyl heptamers (DDPPH and DDOPPH hereafter, respectively) using the techniques of degenerate four-wave mixing (DFWM) and optical Kerr gate (OKG). The studies were performed on the dyes dissolved in THF solution and doped in sol-gel processed composite-glass. The magnitudes and the signs of the real and the imaginary components of the complex third-order optical susceptibilities were determined by the heterodyned OKG method and compared to the values obtained from concentration dependent homodyne Kerr gate and DFWM measurements. The observed effective second hyperpolarizability γ values are dependent on the optical intensity and the pulse width of the pumping source beam. Doping of the dyes in composite-glass allows to increase the interaction length providing the prospect of using them as building blocks for photonic devices.