634 research outputs found
Data-driven parameterized model order reduction using z-domain multivariate orthonormal vector fitting technique
DNA hybridization catalysts and catalyst circuits
Practically all of life's molecular processes, from chemical synthesis to replication, involve enzymes that carry out their functions through the catalysis of metastable fuels into waste products. Catalytic control of reaction rates will prove to be as useful and ubiquitous in
DNA nanotechnology as it is in biology. Here we present experimental results on the control of the decay rates of a metastable DNA "fuel". We show that the fuel complex can be induced to decay with a rate about 1600 times faster than it would decay spontaneously. The original DNA hybridization catalyst [15] achieved a maximal speed-up of roughly 30. The fuel complex discussed here can therefore serve as the basic ingredient for an improved DNA hybridization catalyst. As an example application for DNA hybridization catalysts, we propose a method for implementing arbitrary digital logic circuits
Entanglement, Mixedness, and Spin-Flip Symmetry in Multiple-Qubit Systems
A relationship between a recently introduced multipartite entanglement
measure, state mixedness, and spin-flip symmetry is established for any finite
number of qubits. It is also shown that, within those classes of states
invariant under the spin-flip transformation, there is a complementarity
relation between multipartite entanglement and mixedness. A number of example
classes of multiple-qubit systems are studied in light of this relationship.Comment: To appear in Physical Review A; submitted 14 May 200
Fatigue and physical functioning in children with multiple sclerosis and acute disseminated encephalomyelitis
Background and Objective: Fatigue and physical impairments are a major concern in children with multiple sclerosis (MS) and after acute disseminated encephalomyelitis (post-ADEM). We here aimed to evaluate the interaction between fatigue, exercise capacity, motor performance, neurological status, and quality of life (HRQoL). Methods: In this cross-sectional study, data of 38 children (MS n = 22, post-ADEM n = 16), aged 4–17 years attending our national pediatric MS center, were studied. Fatigue was measured with the Pediatric Quality of Life Multidimensional Fatigue Scale, exercise capacity with the Bruce Protocol, motor performance with the Movement Assessment Battery for Children second edition, HRQoL with the Pediatric Quality of Life Questionnaire, and extent of disability with the Expanded Disability Status Scale (EDSS). Results: Children with MS and post-ADEM experienced more fatigue (p < 0.001), reduced exercise capacity (p < 0.001), and impaired motor performance (p < 0.001), despite low scores on the EDSS. Fatigue, but not the other parameters, was significantly correlated with HRQoL. Fatigue was not correlated with exercise capacity. Conclusion: We confirm the major impact of fatigue on quality of life in children with MS and post-ADEM. Fatigue was not explained by reduced exercise capacity or impaired motor performance. An important finding for clinical practice is that the low EDSS score did not reflect the poor physical functioning
A convenient band-gap interpolation technique and an improved band line-up model for InGaAlAs on InP
The band-gap energy and the band line-up of InGaAlAs quaternary compound material on InP are essential information for the theoretical study of physical properties and the design of optoelectronics devices operating in the long-wavelength communication window. The band-gap interpolation of In1-x-y Ga (x) Al (y) As on InP is known to be a challenging task due to the observed discrepancy of experimental results arising from the bowing effect. Besides, the band line-up results of In1-x-y Ga (x) Al (y) As on InP based on previously reported models have limited success by far. In this work, we propose an interpolation solution using the single-variable surface bowing estimation interpolation method for the fitting of experimentally measured In1-x-y Ga (x) Al (y) As band-gap data with various degree of bowing using the same set of input parameters. The suggested solution provides an easier and more physically interpretable way to determine not only lattice matched, but also strained band-gap energy of In1-x-y Ga (x) Al (y) As on InP based on the experimental results. Interpolated results from this convenient method show a more favourable match to multiple independent experiment data sets measured under different temperature conditions as compared to those obtained from the commonly used weighted-sum approach. On top of that, extended framework of the model-solid theory for the band line-up of In1-x-y Ga (x) Al (y) As/InP heterostructure is proposed. Our model-solid theory band line-up result using the proposed extended framework has shown an improved accuracy over those without the extension. In contrast to some previously reported works, it is worth noting that the band line-up result based on our proposed extended model-solid theory has also shown to be more accurate than those given by Harrison's mode
Multipartite entangled coherent states
We propose a scheme for generating multipartite entangled coherent states via
entanglement swapping, with an example of a physical realization in ion traps.
Bipartite entanglement of these multipartite states is quantified by the
concurrence. We also use the --tangle to compute multipartite entanglement
for certain systems. Finally we establish that these results for entanglement
can be applied to more general multipartite entangled nonorthogonal states.Comment: 7 pages, two figures. We added more detail discussions on the
generation of multipartite entangled coherent states and multipartite
entangelemen
A CsI(Tl) Scintillating Crystal Detector for the Studies of Low Energy Neutrino Interactions
Scintillating crystal detector may offer some potential advantages in the
low-energy, low-background experiments. A 500 kg CsI(Tl) detector to be placed
near the core of Nuclear Power Station II in Taiwan is being constructed for
the studies of electron-neutrino scatterings and other keV-MeV range neutrino
interactions. The motivations of this detector approach, the physics to be
addressed, the basic experimental design, and the characteristic performance of
prototype modules are described. The expected background channels and their
experimental handles are discussed.Comment: 34 pages, 11 figures, submitted to Nucl. Instrum. Method
An analysis of the FIR/RADIO Continuum Correlation in the Small Magellanic Cloud
The local correlation between far-infrared (FIR) emission and radio-continuum
(RC) emission for the Small Magellanic Cloud (SMC) is investigated over scales
from 3 kpc to 0.01 kpc. Here, we report good FIR/RC correlation down to ~15 pc.
The reciprocal slope of the FIR/RC emission correlation (RC/FIR) in the SMC is
shown to be greatest in the most active star forming regions with a power law
slope of ~1.14 indicating that the RC emission increases faster than the FIR
emission. The slope of the other regions and the SMC are much flatter and in
the range of 0.63-0.85. The slopes tend to follow the thermal fractions of the
regions which range from 0.5 to 0.95. The thermal fraction of the RC emission
alone can provide the expected FIR/RC correlation. The results are consistent
with a common source for ultraviolet (UV) photons heating dust and Cosmic Ray
electrons (CRe-s) diffusing away from the star forming regions. Since the CRe-s
appear to escape the SMC so readily, the results here may not provide support
for coupling between the local gas density and the magnetic field intensity.Comment: 19 pages, 7 Figure
The Muonium Atom as a Probe of Physics beyond the Standard Model
The observed interactions between particles are not fully explained in the
successful theoretical description of the standard model to date. Due to the
close confinement of the bound state muonium () can be used as
an ideal probe of quantum electrodynamics and weak interaction and also for a
search for additional interactions between leptons. Of special interest is the
lepton number violating process of sponteanous conversion of muonium to
antimuonium.Comment: 15 pages,6 figure
T-cell activation marker sCD27 is associated with clinically definite multiple sclerosis in childhood-acquired demyelinating syndromes
Background: Cerebrospinal fluid (CSF) levels of T-cell activation marker soluble CD27 (sCD27) are associated with subsequent disease activity after a first attack of suspected MS in adults. The predictive value for disease course in children with acquired demyelinating syndromes (ADS) is unknown. Objectives: To assess the predictive value of sCD27 levels for clinically definite multiple sclerosis (CDMS) diagnosis in childhood ADS. Methods: Children <18 years with a first demyelinating event were prospectively included and followed. Soluble CD27 was determined in CSF using an enzyme-linked immunosorbent assay (ELISA). Cox regression analyses were used to calculate hazard ratios (HRs) for CDMS. Results: A total of 94 ADS children were included (ADS with encephalopathy (ADS+) n = 33 and ADS without encephalopathy (ADS–) n = 61). Of the 61 ADS– children, 21 (48%) were diagnosed with CDMS during follow-up. At baseline, sCD27 levels were higher in patients with a future CDMS diagnosis (n = 29) than in monophasic ADS+ (n = 30), monophasic ADS– (n = 28) and relapsing non-MS patients (n = 7; p < 0.001). In ADS– patients, sCD27 was associated with CDMS (HR = 1.8 per 100 U/mL increase in sCD27 levels, p = 0.031), after adjustments for age, oligoclonal bands and the presence of dissemination in space on baseline magnetic resonance imaging (MRI). Conclusion: CSF sCD27 levels at first attack of demyelination were associated with CDMS diagnosis in children. This makes sCD27 a potential clinically relevant quantitative marker when performing routine CSF diagnostics
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