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Selected Abstracts1244: Diagnostic look-a-likesACTA OPHTHALMOLOGICA, Issue 2010A KAWASAKI Purpose To provide the clinician with specific tips on how to distinguish between two common "look-alike" diagnoses Methods Case studies Results We will highlight the one best feature that differentiates the two disorders presented as look-alikes Conclusion It is important to recognize disorders that have similar presentation and to know how best to differentiate between them Commercial interest [source] A terminal-controlled vertical handover decision scheme in IEEE 802.21-enabled heterogeneous wireless networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2009Jung-Shyr Wu Abstract The seamless internetworking among heterogeneous networks is in great demand to provide ,always-on' connectivity services with quality of service (QoS) provision, anywhere at anytime. The integration of wireless-fidelity (Wi-Fi) and wireless metropolitan area networks (WiMAX) networks can combine their best features to provide ubiquitous access, while mediating the weakness of both networks. While it is challenging to obtain optimized handover decision-based dynamic QoS information, users can improve their perceived QoS by using the terminal-controlled handover decision in a single device equipped with multiple radio interfaces. The IEEE 802.21 aims at providing a framework that defines media-independent handover (MIH) mechanism that supports seamless handover across heterogeneous networks. In this paper, an multiple attributes decision making-based terminal-controlled vertical handover decision scheme using MIH services is proposed in the integrated Wi-Fi and WiMAX networks to provide ,always-on' connectivity QoS services. The simulation results show that the proposed scheme provides smaller handover times and lower dropping rate than the RSS-based and cost function-based vertical handover schemes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Stochastic Volatility in a Macro-Finance Model of the U.S. Term Structure of Interest Rates 1961,2004JOURNAL OF MONEY, CREDIT AND BANKING, Issue 6 2008PETER D. SPENCER affine term structure model; macro finance; unit root; stochastic volatility This paper generalizes the standard homoscedastic macro-finance model by allowing for stochastic volatility, using the "square root" specification of the mainstream finance literature. Empirically, this specification dominates the standard model because it is consistent with the square root volatility found in macroeconomic time series. Thus it establishes an important connection between the stochastic volatility of the mainstream finance model and macro-economic volatility of the Okun,Friedman type. This research opens the way to a richer specification of both macro-economic and term structure models, incorporating the best features of both macro-finance and mainstream finance models. [source] Fully automatic, retrospective enhancement of real-time acquired cardiac cine MR images using image-based navigators and respiratory motion-corrected averagingMAGNETIC RESONANCE IN MEDICINE, Issue 4 2008Peter Kellman Abstract Real-time imaging may be clinically important in patients with congestive heart failure, arrhythmias, or in pediatric cases. However, real-time imaging typically has compromised spatial and temporal resolution compared with gated, segmented studies. To combine the best features of both types of imaging, a new method is proposed that uses parallel imaging to improve temporal resolution of real-time acquired images at the expense of signal-to-noise ratio (SNR), but then produces an SNR-enhanced cine by means of respiratory motion-corrected averaging of images acquired in real-time over multiple heartbeats while free-breathing. The retrospective processing based on image-based navigators and nonrigid image registration is fully automated. The proposed method was compared with conventional cine images in 21 subjects. The resultant image quality for the proposed method (3.9 ± 0.44) was comparable to the conventional cine (4.2 ± 0.99) on a 5-point scale (P = not significant [n.s.]). The conventional method exhibited degraded image quality in cases of arrhythmias whereas the proposed method had uniformly good quality. Motion-corrected averaging of real-time acquired cardiac images provides a means of attaining high-quality cine images with many of the benefits of real-time imaging, such as free-breathing acquisition and tolerance to arrhythmias. Magn Reson Med, 2007. © 2008 Wiley-Liss, Inc. [source] In search for more accurate alignments in the twilight zonePROTEIN SCIENCE, Issue 7 2002Lukasz Jaroszewski Abstract A major bottleneck in comparative modeling is the alignment quality; this is especially true for proteins whose distant relationships could be reliably recognized only by recent advances in fold recognition. The best algorithms excel in recognizing distant homologs but often produce incorrect alignments for over 50% of protein pairs in large fold-prediction benchmarks. The alignments obtained by sequence,sequence or sequence,structure matching algorithms differ significantly from the structural alignments. To study this problem, we developed a simplified method to explicitly enumerate all possible alignments for a pair of proteins. This allowed us to estimate the number of significantly different alignments for a given scoring method that score better than the structural alignment. Using several examples of distantly related proteins, we show that for standard sequence,sequence alignment methods, the number of significantly different alignments is usually large, often about 1010 alternatives. This distance decreases when the alignment method is improved, but the number is still too large for the brute force enumeration approach. More effective strategies were needed, so we evaluated and compared two well-known approaches for searching the space of suboptimal alignments. We combined their best features and produced a hybrid method, which yielded alignments that surpassed the original alignments for about 50% of protein pairs with minimal computational effort. [source] New isotope ratio mass spectrometric method of precise ,37Cl determinationsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2009Stanislaw Halas The most precise method of chlorine isotope analysis described to date is based on the isotope ratio mass spectrometry (IRMS) of chlorine quantitatively converted into chloromethane, CH3Cl. This gas can be produced from several chlorine-containing compounds and analyzed by IRMS. However, the mass spectrum of chloromethane is rather complicated and the ratio of the most abundant ions (mass-52/mass-50) differs from the 37Cl/35Cl isotope ratio. This difference becomes significant when the , exceeds 10,. Moreover, the electron ionization source yields approximately 80% of all the ionic species at the useful masses 50 and 52. To overcome these drawbacks, we have devised a negative ion mass spectrometer which retains all the best features of IRMS, including a dual-inlet system with changeover valve, dual collector assembly and CH3Cl gas as analyte. In the modified ion source we have replaced the ionization chamber with an electron beam by a metal tube with a hot metal filament inside it. Within this tube the 35Cl, and 37Cl, ions are produced with an efficiency dependent on the filament material and its temperature. No other ionic species were found in the mass spectrum except of traces at masses 26 and 28 at ppm levels, probably due to the formation of CN, and CO,. The minimal amount of Cl used in our method is of the order of 5,µmol (3,mg AgCl) and the precision is better than 0.005, (1,). Copyright © 2009 John Wiley & Sons, Ltd. [source] Efficient quadrature and node positioning for exotic option valuationTHE JOURNAL OF FUTURES MARKETS, Issue 11 2010San-Lin Chung We combine the best features of two highly successful quadrature option pricing streams, improving the linked issues of numerical precision and abscissa positioning. Coupling the recombining abscissa (node) approach used in Andricopoulos, A., Widdicks, M., Duck, P., and Newton, D.P. (2003) (AWDN as well as AWND, 2007) with the Gauss-Legendre Quadrature (GQ) method of Sullivan, M.A. (2000) yields highly accurate and efficient option prices for a range of standard and exotic specifications including barrier options and in particular for NGARCH, CEV, and jump-diffusion processes. The improvements are due to manner in which GQ positions nodes and the use of these values without interpolation. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark [source] | ||||||||||||||||