Obstructive sleep apnea syndrome (OSAS) is observed in approximately 2% of children. Heart rate variability (HRV) is a potentially simple, non-invasive diagnostic screening tool for OSAS. In this study, we investigate...
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Obstructive sleep apnea syndrome (OSAS) is observed in approximately 2% of children. Heart rate variability (HRV) is a potentially simple, non-invasive diagnostic screening tool for OSAS. In this study, we investigated the diagnostic potential of HRV using power spectral analysis, numerical titration, sample entropy, and detrended fluctuation analysis. Effects of sleep stages (REM and NREM sleep) are evaluated. The results show that the heart rate chaos intensity, as measured by the noise limit in numerical titration, is significantly higher during REM sleep than NREM sleep in all patient groups. By using the receiver-operating characteristic analysis, the detection of OSAS yielded a specificity of 72.2% and sensitivity of 81.3% using the numerical-titration technique. The findings suggest that sleep state and disordered breathing are important determinants of cardiac autonomic control. Nonlinear techniques such as numerical titration, when used in conjunction with spectral analysis of HRV could be an effective screening tool for pediatric OSAS
Using a confocal micro-Raman system, spectra showing the splitting of optical transitions due to trigonal warping effect are presented for metallic single-wall carbon nanotubes (SWNT’s). Our results indicate that the...
Using a confocal micro-Raman system, spectra showing the splitting of optical transitions due to trigonal warping effect are presented for metallic single-wall carbon nanotubes (SWNT’s). Our results indicate that the intensity variations between different optical transitions can be attributed primarily to the differences in the magnitude of the electron-phonon coupling matrix elements. Our approach will allow the study of the magnitude of electron-phonon matrix elements as well as quantum interference effects between different transitions in metallic SWNT’s.
A new regime of coherent quantum dynamics of a qubit is realized at low driving frequencies in the strong driving limit. Coherent transitions between qubit states occur via the Landau-Zener process when the system is ...
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A new regime of coherent quantum dynamics of a qubit is realized at low driving frequencies in the strong driving limit. Coherent transitions between qubit states occur via the Landau-Zener process when the system is swept through an energy-level avoided crossing. The quantum interference mediated by repeated transitions gives rise to an oscillatory dependence of the qubit population on the driving-field amplitude and flux detuning. These interference fringes, which at high frequencies consist of individual multiphoton resonances, persist even for driving frequencies smaller than the decoherence rate, where individual resonances are no longer distinguishable. A theoretical model that incorporates dephasing agrees well with the observations.
High-throughput generation of new types of relational biological datasets is creating a demand for network-based signal processing and pattern recognition to provide new insights. Such networks are often too large to ...
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High-throughput generation of new types of relational biological datasets is creating a demand for network-based signal processing and pattern recognition to provide new insights. Such networks are often too large to interpret visually and too complicated to be explained solely based on local topological properties. Just as signal processing and statistical techniques have been used in traditional, sequential-based biological datasets, so too are methodologies needed to automatically discern patterns in the huge, emerging networks. One way to do this is by transforming these very large networks into discernable epitomes, or abstracts, of the original networks. This work presents an approach for doing this via topological compression. Through capturing nodes' global topologies and subsequent compression, a new network epitome can be derived. Here, this is done with an E. Coli gene regulation network, resulting in biological findings that could not be derived from the local topology of the original network.
In this paper, we investigate the properties of lethal genes in E. coli, our model organism. Topological analysis of networks of functional interactions among genes has shown that lethal genes share common local conne...
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In this paper, we investigate the properties of lethal genes in E. coli, our model organism. Topological analysis of networks of functional interactions among genes has shown that lethal genes share common local connectivity properties. In this paper, we analyze cellular networks across three domains. We show that a stochastic global topological analysis, via random walks, is more effective at predicting gene lethality than simply looking at local topology using the standard hub-based method. We also introduce the possibility of using metabolic pathways to understand lethal genes, as regulating these pathways is among one of the most important functions of the gene-encoded proteins. Additionally, we analyze lethal genes in terms of the Gene Ontology (GO) and find that the graph forms two highly connected clusters that are each GO enriched for specific terms. We also find that lethal metabolic regulators are extremely enriched. Finally, we provide applications of the work and avenues for future research.
Why is the optical network to date not as successful commercially as many previously thought it would be and what can the research community do to help? The author offers his opinion on this question. When one gives t...
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Why is the optical network to date not as successful commercially as many previously thought it would be and what can the research community do to help? The author offers his opinion on this question. When one gives the first part of this question some thought, several possibilities naturally come to mind: has the cause been substandard optical network performance? Have venture capitalists and entrepreneurs killed the market with glut by miscalculating and overbuilding the core? In my view, both contributed to the problem, but mostly, it is that optical networks have been engineered with insufficient attention given to the cost incurred by the end-user.
The advent of network coding has blurred the line between compression and routing in networks. In this talk, we overview the main principles of network coding and discuss the applicability of network coding to wireles...
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The advent of network coding has blurred the line between compression and routing in networks. In this talk, we overview the main principles of network coding and discuss the applicability of network coding to wireless network settings. In particular, we argue that the ablity to construct both network codes and minimum-cost subgraphs in a completely distributed fashion may provide considerable improvements, in performance and in ease of network management, over current routing-based approaches.
This paper presents the design and an evaluation of Mondrix, a version of the Linux kernel with Mondriaan Memory Protection (MMP). MMP is a combination of hardware and software that provides efficient fine-grained mem...
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This paper presents the design and an evaluation of Mondrix, a version of the Linux kernel with Mondriaan Memory Protection (MMP). MMP is a combination of hardware and software that provides efficient fine-grained memory protection between multiple protection domains sharing a linear address space. Mondrix uses MMP to enforce isolation between kernel modules which helps detect bugs, limits their damage, and improves kernel robustness and maintainability. During development, MMP exposed two kernel bugs in common, heavily-tested code, and during fault injection experiments, it prevented three of five file system corruptions. The Mondrix implementation demonstrates how MMP can bring memory isolation to modules that already exist in a large software application. It shows the benefit of isolation for robustness and error detection and prevention, while validating previous claims that the protection abstractions MMP offers are a good fit for software. This paper describes the design of the memory supervisor, the kernel module which implements permissions policy. We present an evaluation of Mondrix using full-system simulation of large kernel-intensive workloads. Experiments with several benchmarks where MMP was used extensively indicate the additional space taken by the MMP data structures reduce the kernel's free memory by less than 10%, and the kernel's runtime increases less than 15% relative to an unmodified kernel. Copyright 2005 ACM.
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