Quantum rainbow scattering at tunable velocities

Elastic scattering cross sections are measured for lithium atoms colliding with rare gas atoms and SF6 molecules at tunable relative velocities down to ~50 m/s. Our scattering apparatus combines a velocity-tunable molecular beam with a magneto-optic trap that provides an ultracold cloud of lithium atoms as a scattering target. Comparison with theory reveals the quantum nature of the collision dynamics in the studied regime, including both rainbows as well as orbiting resonances

The nonperturbative closed string tachyon vacuum to high level

We compute the action of closed bosonic string field theory at quartic order with fields up to level ten. After level four, the value of the potential at the minimum starts oscillating around a nonzero negative value, in contrast with the proposition made in [5]. We try a different truncation scheme in which the value of the potential converges faster with the level. By extrapolating these values, we are able to give a rather precise value for the depth of the potential.Comment: 24 pages. v2: typos corrected, clarified extrapolation in scheme B, and added extrapolated tachyon and dilaton vev's at the end of Section

Exudative pharyngitis possibly due to Corynebacterium pseudodiphtheriticum, a new challenge in the differential diagnosis of diphtheria.

Corynebacterium pseudodiphtheriticum has rarely been reported to cause disease in humans, despite its common presence in the flora of the upper respiratory tract. We report here a case of exudative pharyngitis with pseudomembrane possibly caused by C. pseudodiphtheriticum in a 4-year-old girl. The case initially triggered clinical and laboratory suspicion of diphtheria. Because C. pseudodiphtheriticum can be easily confused with Corynebacterium diphtheriae in Gram stain, clarification of its role in the pathogenesis of exudative pharyngitis in otherwise healthy persons is of public health importance. Simple and rapid screening tests to differentiate C. pseudodiphtheriticum from C. diphtheriae should be performed to prevent unnecessary concern in the community and unnecessary outbreak control measures

Improved setup for producing slow beams of cold molecules using a rotating nozzle

Intense beams of cold and slow molecules are produced by supersonic expansion out of a rapidly rotating nozzle, as first demonstrated by Gupta and Herschbach. An improved setup is presented that allows to accelerate or decelerate cold atomic and molecular beams by up to 500 m/s. Technical improvements are discussed and beam parameters are characterized by detailed analysis of time of flight density distributions. The possibility of combining this beam source with electrostatic fields for guiding polar molecules is demonstrated

On field theory quantization around instantons

With the perspective of looking for experimentally detectable physical applications of the so-called topological embedding, a procedure recently proposed by the author for quantizing a field theory around a non-discrete space of classical minima (instantons, for example), the physical implications are discussed in a ``theoretical'' framework, the ideas are collected in a simple logical scheme and the topological version of the Ginzburg-Landau theory of superconductivity is solved in the intermediate situation between type I and type II superconductors.Comment: 27 pages, 5 figures, LaTe

Molecular Dynamics Simulation of Semiflexible Polyampholyte Brushes - The Effect of Charged Monomers Sequence

Planar brushes formed by end-grafted semiflexible polyampholyte chains, each chain containing equal number of positively and negatively charged monomers is studied using molecular dynamics simulations. Keeping the length of the chains fixed, dependence of the average brush thickness and equilibrium statistics of the brush conformations on the grafting density and the salt concentration are obtained with various sequences of charged monomers. When similarly charged monomers of the chains are arranged in longer blocks, the average brush thickness is smaller and dependence of brush properties on the grafting density and the salt concentration is stronger. With such long blocks of similarly charged monomers, the anchored chains bond to each other in the vicinity of the grafting surface at low grafting densities and buckle toward the grafting surface at high grafting densities.Comment: 8 pages,7 figure

Robotic-assisted laparoscopic extended pelvic lymph node dissection for prostate cancer: surgical technique and experience with the first 99 cases

BACKGROUND: To date, there is still a paucity of data in the literature on robotic-assisted laparoscopic extended pelvic lymph node dissection (RALEPLND) in patients with prostate cancer. OBJECTIVE: To assess the technical feasibility of RALEPLND and to present our surgical technique. DESIGN, SETTING, AND PARTICIPANTS: From April 2006 to March 2008, we performed RALEPLND in 99 patients prior to robotic-assisted laparoscopic radical prostatectomy. Indications for RALEPLND were a prostate-specific antigen (PSA) >/=10 ng/ml or a preoperative Gleason score >/=7. The data were evaluated retrospectively. SURGICAL PROCEDURE: The transperitoneal approach was used in all cases. In order to gain optimal access to the common iliac bifurcation, the five trocars were placed in a more cephalad position than in patients undergoing radical prostatectomy without RALEPLND. After identification of important landmarks, the lymphatics covering the external iliac vein, the obturator lymphatic packet, and the lymphatics overlying the internal iliac artery were removed on both sides. MEASUREMENTS: The total lymph node yield, the frequency of lymph node metastases, and the complication rate. RESULTS AND LIMITATIONS: The median patient age was 64 yr (range: 45-78). The median preoperative PSA level was 7.7 ng/ml (range: 1.5-84.6). The median number of lymph nodes harvested was 19 (range: 8-53). In 16 patients (16%), we found lymph node metastasis. Complications occurred in seven patients (7%). CONCLUSIONS: RALEPLND is feasible, and its lymph node yield is well in the range of open series. The robotic-assisted laparoscopic approach in itself does not seem to limit a surgeon's ability to perform a complete extended pelvic lymph node dissection

Diagnostisches und therapeutisches Vorgehen in der Akutphase nach kranio-zervikalem Beschleunigungstrauma (sog. Schleudertrauma) : Empfehlungen einer schweizerischen Arbeitsgruppe

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