714 research outputs found
Kondo screening in a magnetically frustrated nanostructure: Exact results on a stable, non-Fermi-liquid phase
Triangular symmetry stabilizes a novel non-Fermi-liquid phase in the
three-impurity Kondo model with frustrating antiferromagnetic interactions
between half-integer impurity spins. The phase arises without fine-tuning of
couplings, and is stable against magnetic fields and particle-hole symmetry
breaking. We find a conformal field theory describing this phase, verify it
using the numerical renormalization group, and extract various exact, universal
low-energy properties. Signatures predicted in electrical transport may be
testable in scanning tunneling microscopy or quantum-dot experiments.Comment: 4 pages, published version (shortened, minor corrections
Stainless Steel Crown Success Using the Hall Technique: A Retrospective Study
Background
In this retrospective study, the authors evaluated the clinical and radiographic success of stainless steel crowns (SSCs) used to restore primary molars with caries lesions, placed by means of both the traditional technique (involving complete caries removal and tooth reduction before placement of the SSC) and the Hall technique (involving no caries removal, no crown preparation and no use of local anesthetic before placement of the SSC).
Methods
The authors conducted a retrospective chart review by using the patient records at a private pediatric dental practice at which the Hall technique had been introduced in June 2010 as an alternative treatment to traditional SSC placement. The inclusion criteria were caries lesions on a primary molar with no clinical or radiographic evidence of pulpitis, necrosis or abscess, as well as follow-up of at least six months or until failure, whichever came first. They graded restoration success by using a four-point scale based on presence or loss of the SSC, and whether or not the patient needed further treatment associated with pulpal pathology or secondary caries. They collected and summarized patient demographic information. They used a Kaplan-Meier survival curve along with 95 percent confidence intervals to evaluate clinical success.
Results
The authors found that 65 (97 percent) of 67 SSCs placed with the Hall technique (mean observation time, 15 months; range, four-37 months) and 110 (94 percent) of 117 SSCs placed with the traditional technique (mean observation time, 53 months; range, four-119 months) were successful.
Conclusion
Findings of this study show a similar success rate for SSCs placed with the traditional technique or the Hall technique
BimodalGaze:Seamlessly Refined Pointing with Gaze and Filtered Gestural Head Movement
Eye gaze is a fast and ergonomic modality for pointing but limited in precision and accuracy. In this work, we introduce BimodalGaze, a novel technique for seamless head-based refinement of a gaze cursor. The technique leverages eye-head coordination insights to separate natural from gestural head movement. This allows users to quickly shift their gaze to targets over larger fields of view with naturally combined eye-head movement, and to refine the cursor position with gestural head movement. In contrast to an existing baseline, head refinement is invoked automatically, and only if a target is not already acquired by the initial gaze shift. Study results show that users reliably achieve fine-grained target selection, but we observed a higher rate of initial selection errors affecting overall performance. An in-depth analysis of user performance provides insight into the classification of natural versus gestural head movement, for improvement of BimodalGaze and other potential applications
Development of a Fast Position-Sensitive Laser Beam Detector
We report the development of a fast position-sensitive laser beam detector
with a bandwidth that exceeds currently available detectors. The detector uses
a fiber-optic bundle that spatially splits the incident beam, followed by a
fast balanced photo-detector. The detector is applied to the study of Brownian
motion of particles on fast time scales with 1 Angstrom spatial resolution.
Future applications include the study of molecule motors, protein folding, as
well as cellular processes
Immune Network Algorithm applied to the Optimization of Composite SaaS in Cloud Computing
Abstract-In order to serve the different application needs of the different Cloud users efficiently and effectively, a possible solution is the decomposition of the software or so-called composite SaaS (Software as a Service). A composite SaaS constitutes a group of loosely-coupled applications that communicate with each other to form higher-level functionality. The benefits to the SaaS providers are reduced delivery cost and flexible SaaS functions, and the benefit for the users is the decreased cost of subscription. For this to be achieved effectively, the optimization of the process is required in order to manage the SaaS resources in the data center efficiently. In this paper, the optimization task of composite SaaS is investigated using an Immune network optimization approach. The approach makes use of activation and suppression that are mimicked by the natural immune system triggering an immune response not only when antibodies interact with antigens but also when they interact with other antibodies. Experiments are conducted with a series of SaaS configurations and the proposed immune network algorithm is compared with a formerly proposed grouping genetic algorithm. The results show that the immune network algorithm outperforms the grouping genetic algorithm
The CoRoT target HD 49933 . I. Effect of the metal abundance on the mode excitation rates
Context. Solar-like oscillations are stochastically excited by turbulent convection at the surface layers of the stars. Aims: We study the role of the surface metal abundance on the efficiency of the stochastic driving in the case of the CoRoT target HD 49933. Methods: We compute two 3D hydrodynamical simulations representative - in effective temperature and gravity - of the surface layers of the CoRoT target HD 49933, a star that is rather metal poor and significantly hotter than the Sun. One 3D simulation has a solar metal abundance, and the other has a surface iron-to-hydrogen, [Fe/H], abundance ten times smaller. For each 3D simulation we match an associated global 1D model, and we compute the associated acoustic modes using a theoretical model of stochastic excitation validated in the case of the Sun and α Cen A. Results: The rate at which energy is supplied per unit time into the acoustic modes associated with the 3D simulation with [Fe/H] = -1 is found to be about three times smaller than those associated with the 3D simulation with [Fe/H] = 0. As shown here, these differences are related to the fact that low metallicity implies surface layers with a higher mean density. In turn, a higher mean density favors smaller convective velocities and hence less efficient driving of the acoustic modes. Conclusions: Our result shows the importance of taking the surface metal abundance into account in the modeling of the mode driving by turbulent convection. A comparison with observational data is presented in a companion paper using seismic data obtained for the CoRoT target HD 49933. The CoRoT space mission, launched on December 27, 2006, has been developped and is operated by CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany and Spain
Temporal Changes in Alcohol-Related Morbidity and Mortality in Germany
Aims: Trends in morbidity and mortality, fully or partially attributable to alcohol, for adults aged 18–64 were assessed for Germany. Methods: The underestimation of population exposure was corrected by triangulating survey data with per capita consumption. Alcohol-attributable fractions by sex and two age groups were estimated for major disease categories causally linked to alcohol. Absolute numbers, population rates and proportions relative to all hospitalizations and deaths were calculated. Results: Trends of 100% alcohol-attributable morbidity and mortality over thirteen and eighteen years, respectively, show an increase in rates of hospitalizations and a decrease in mortality rates. Comparisons of alcohol-attributable morbidity including diseases partially caused by alcohol revealed an increase in hospitalization rates between 2006 and 2012. The proportion of alcohol-attributable hospitalizations remained constant. Rates of alcohol-attributable mortality and the proportion among all deaths decreased. Conclusions: The increasing trend in mortality due to alcohol until the mid-1990s has reversed. The constant proportion of all hospitalizations that were attributable to alcohol indicates that factors such as improved treatment and easier health care access may have influenced the general increase in all-cause morbidity. To further reduce alcohol-related mortality, efforts in reducing consumption and increasing treatment utilization are needed
Preserving cultural heritage: Analyzing the antifungal potential of ionic liquids tested in paper restoration
Early industrialization and the development of cheap production processes for paper have led to an exponential accumulation of paper-based documents during the last two centuries. Archives and libraries harbor vast amounts of ancient and modern documents and have to undertake extensive endeavors to protect them from abiotic and biotic deterioration. While services for mechanical preservation such as ex post de-acidification of historic documents are already commercially available, the possibilities for long-term protection of paper-based documents against fungal attack (apart from temperature and humidity control) are very limited. Novel processes for mechanical enhancement of damaged cellulosic documents use Ionic Liquids (IL) as essential process components. With some of these ILs having azolefunctionalities similar to well-known fungicides such as Clotrimazole, the possibility of antifungal activities of these ILs was proposed but has not yet been experimentally confirmed. We evaluated the potency of four ILs with potential application in paper restoration for suppression of fungal growth on five relevant paper-infesting molds. The results revealed a general antifungal activity of all ILs, which increased with the size of the non-polar group. Physiological experiments and ultimate elemental analysis allowed to determine the minimal inhibitory concentration of each IL as well as the residual IL concentration in process-treated paper. These results provide valuable guidelines for IL-applications in paper restoration processes with antifungal activity as an added benefit. With azoles remaining in the paper after the process, simultaneous repair and biotic protection in treated documents could be facilitated
Maskless Photolithography System
Final report for Project 02 of ME450, Winter 2009 semester.Photolithography is a key process in the semiconductor industry (e.g. in the integrated circuit and MEMS industry) that is based on the use of expensive optical equipment (steppers) to pattern micron-size features on silicon wafers. The goal of
the project is to manufacture an inexpensive, photolithographic system for photo-patterning submicron-resolution features.Nikos Chronis (Mechanical Engineering, U of M)http://deepblue.lib.umich.edu/bitstream/2027.42/86196/1/ME450 Fall2009 Final Report - Project 02 - Maskless Photolithography System.pd
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