Three-cell traveling wave superconducting test structure

Use of a superconducting traveling wave accelerating (STWA) structure with a small phase advance per cell rather than a standing wave structure may provide a significant increase of the accelerating gradient in the ILC linac. For the same surface electric and magnetic fields the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing wave cavities. The STWA allows also longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed, manufactured and successfully tested demonstrating the possibility of a proper processing to achieve a high accelerating gradient. These results open way to take the next step of the TW SC cavity development: to build and test a traveling-wave three-cell cavity with a feedback waveguide. The latest results of the single-cell cavity tests are discussed as well as the design of the test 3-cell TW cavity.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr 2011: New York, US

ReaxFF parameter optimization with Monte-Carlo and evolutionary algorithms : guidelines and insights

ReaxFF is a computationally efficient force field to simulate complex reactive dynamics in extended molecular models with diverse chemistries, if reliable force-field parameters are available for the chemistry of interest. If not, they must be optimized by minimizing the error ReaxFF makes on a relevant training set. Because this optimization is far from trivial, many methods, in particular, genetic algorithms (GAs), have been developed to search for the global optimum in parameter space. Recently, two alternative parameter calibration techniques were proposed, that is, Monte-Carlo force field optimizer (MCFF) and covariance matrix adaptation evolutionary strategy (CMA-ES). In this work, CMA-ES, MCFF, and a GA method (OGOLEM) are systematically compared using three training sets from the literature. By repeating optimizations with different random seeds and initial parameter guesses, it is shown that a single optimization run with any of these methods should not be trusted blindly: nonreproducible, poor or premature convergence is a common deficiency. GA shows the smallest risk of getting trapped into a local minimum, whereas CMA-ES is capable of reaching the lowest errors for two-third of the cases, although not systematically. For each method, we provide reasonable default settings, and our analysis offers useful guidelines for their usage in future work. An important side effect impairing parameter optimization is numerical noise. A detailed analysis reveals that it can be reduced, for example, by using exclusively unambiguous geometry optimization in the training set. Even without this noise, many distinct near-optimal parameter vectors can be found, which opens new avenues for improving the training set and detecting overfitting artifacts

Preperitoneal Blockade in the Treatment of Patients with Perforated Gastroduodenal Ulcers and Peritonitis

The objective of this study was to improve the results of surgical treatment for patients with perforated gastroduodenal ulcers and peritonitis (PGDU-P) by applying the preperitoneal blockade. Materials and Methods: The study included 102 patients with perforated gastroduodenal ulcers (PGDU) complicated by peritonitis. Patients between 18 and 30 years were predominant. Pain was measured using the Visual Analog Scale (VAS) for Pain. The measurements of intra-abdominal pressure (IAP) by indirect infravesical tensometry were performed daily from the first day after the operation. Surgical interventions (laparotomy, laparoscopic suturing of PGDU, sanitation and drainage of the abdominal cavity) was performed under endotracheal anesthesia in all patients. Patients were divided into two groups depending on the method of postoperative analgesia. Patients of Group 1 (n=62) were subjected only to systemic opioid analgesia (an intramuscular injection of 1% solution of Promedol 1ml 4 times a day). Patients of Group 2 were subjected to systemic opioid analgesia and catheterization of the preperitoneal space for infusion of 0.5% solution of Novocaine in the postoperative period. Results: Postoperative analgesia using preperitoneal blockade after laparotomy and suturing of perforated gastroduodenal ulcers reduced the pain intensity by 2 times in comparison with conventional analgesia. The preperitoneal blockade after laparotomy in PGDU-P patients promotes the effective reduction of intra-abdominal hypertension (IAH) for 2 days. The comparative evaluation of the incidence of the early postoperative complications showed that using preperitoneal blockade contributed to significantly reducing the complications in Group 2. Postoperative mortality was 1.6% in Group 1 and 0 in Group 2. The average length of stay was reduced by approximately 3 days in Group 2 compared to traditional anesthesia

Action of different treatments based on the mal e effect on the restart of the seasonal reproductive activity of Churra Galega Bragançana ewes

Este ensaio foi realizado com o intuito de estudar a acção do "efeito macho" sobre o restabelecimento da actividade reprodutora sazonal das ovelhas da raça Churra Galega Bragançana. Por outro lado, procurou-se averiguar do possível interesse da aplicação coordenada do "efeito macho" e de tratamentos com acetato de fluorgesterona (FGA) e gonadotropina sérica da égua gestante (PMSG) no restabelecimento desta mesma actividade reprodutora. Neste sentido, um grupo de 135 ovelhas da raça Churra Galega Bragançana, com idades compreendidas entre os 2 e os 4 anos e que haviam parido pela última vez há cerca de 6 meses, foi preparado para a realização deste estudo. Depois de retirar do ensaio todas as ovelhas que apresentavam actividade ovárica completa, aplicaram-se às restantes fêmeas quatro tratamentos distintos: EM • "efeito macho" (n=26); EM+FGA • "efeito macho" + esponjas vaginais com 30 mg de FGA (n=10); EM+PMSG • "efeito macho" + 600 UI de PMSG (n=10) e EM+FGA+PMSG ·"efeito macho" + esponjas vaginais com 30 mg de FGA + 600 UI de PMSG (n=10). No mês de Junho do ano estudado, 58,5% das ovelhas da raça Churra Galega Bragançana inicialmente seleccionadas para a realização deste trabalho apresentavam actividade ovárica completa. Das que se encontravam anéstricas, 87,0% respondeu à aplicação dos tratamentos. Esta resposta não variou em função do tratamento aplicado. De Igual modo, a resposta ovárica das ovelhas estudadas não foi afectada pelo tipo de tratamento empregue. Os tratamentos com FGA melhoraram a resposta comportamental das ovelhas aquando da primeira ovulação. Por seu turno, a adição de PMSG ao " efeito macho" permitiu elevar a resposta comportamental das ovelhas no momento da segunda ovulação. Neste ensaio, a taxa ovulatória média total apresentada pelas ovelhas Churras Bragançanas foi de 1,2±0,9

Polarization resolved angular patterns in nematic liquid crystal cells

We study the angular structure of polarization of light transmitted through a nematic liquid crystal (NLC) cell by theoretically analyzing the polarization state as a function of the incidence angles. For a uniformly aligned NLC cell, the $4\times 4$ matrix formalism and the orthogonality relations are used to derive the analytical expressions for the transmission and reflection matrices. The polarization resolved angular patterns in the two-dimensional projection plane are characterized in terms of the polarization singularities: C points (points of circular polarization) and L lines (lines of linear polarization). In the case of linearly polarized plane waves incident on the homeotropically aligned cell, we present the results of detailed theoretical analysis describing the structure of the polarization singularities. We apply the theory to compute the polarization patterns for various orientational structures in the NLC cell and discuss the effects induced by the director orientation and biaxiality.Comment: pdflatex, rextex4, 22 pages, 7 figures (jpeg

Quantum chemical study of regular and irregular geometries of MgO nanoclusters: Effects on magnetizability, electronic properties and physical characteristics

Advanced materials and surfaces are key components in nanotechnology and are applied by their magnetizable and spintronic properties, high-frequency scattering, and properties attributing to nanoelectronics and nanomagnetic components. Earth oxides are a group of materials with catalytic effects in nanocrystalline forms, and strong magnetic field effects with promising applications in nanomagnetics as well as potential key parts in memory processing units. Their electronic properties in nanocrystalline forms are however not fully understood, and as nanocrystal species behave differently from bulk material, the electronic properties of a set of MgO clusters in small, large, regular and irregular geometries and forms are here studied using the B3LYP and M06-2X levels of quantum theory. The analysis show that particularly the thin sheet MgO clusters exert high diamagnetic properties. Furthermore, vacancies of MgO induce interesting effects at the orbital gap-level and on the electronic populations of the clusters. A NBO analysis shows furthermore that the electronic population in irregular clusters missing MgO units, is quite different from regular structures which highlights that material deficiencies may induce different chemical reactivities and physical effects. The results supplied here show that computational quantum mechanical approaches are of significant value for studying and engineering nanoparticles and nanoclusters, with particular relevance to the emerging methods of nanoscaling by nanophotonic processes, for synthesis and industrial application of nanoparticle MgO in nanoelectronics