3,043 research outputs found
Degree of randomness: numerical experiments for astrophysical signals
Astrophysical and cosmological signals such as the cosmic microwave
background radiation, as observed, typically contain contributions of different
components, and their statistical properties can be used to distinguish one
from the other. A method developed originally by Kolmogorov is involved for the
study of astrophysical signals of randomness of various degrees. Numerical
performed experiments based on the universality of Kolmogorov distribution and
using a single scaling of the ratio of stochastic to regular components, reveal
basic features in the behavior of generated signals also in terms of a critical
value for that ratio, thus enable the application of this technique for various
observational datasetsComment: 6 pages, 9 figures; Europhys.Letters; to match the published versio
Development of responder definitions for fibromyalgia clinical trials
Objective To develop responder definitions for fibromyalgia (FM) clinical trials using key symptom and function domains. Methods Twentyâfour candidate responder definitions were developed by expert consensus and were evaluated in 12 randomized, placeboâcontrolled trials of 4 medications for the treatment of FM. For each definition, the treatment effects of the medication compared with placebo were analyzed using CochranâMantelâHaenszel tests or chiâsquare tests. A metaâanalysis of the pooled results for the 4 medications established risk ratios to determine the definitions that best favored medication over placebo. Results Two definitions performed best in the analyses. Both definitions included â„30% reduction in pain and â„10% improvement in physical function. The definitions differed in that one (â„30% improvement in FM [FM30] short version) included â„30% improvement in sleep or fatigue, and the other (FM30 long version) required â„30% improvement in 2 of the following symptoms: sleep, fatigue, depression, anxiety, or cognition. In the analysis of both versions, the response rate was â„15% for each medication and was significantly greater compared with placebo. The risk ratio favoring drug over placebo in the pooled analysis for FM30 version 3 (short version) was 1.50 (95% confidence interval [95% CI] 1.24â1.82; P †0.0001); the risk ratio for FM30 version 6 (long version) was 1.60 (95% CI 1.31â1.96; P †0.00001). Conclusion Among the 24 responder definitions tested, 2 were identified as most sensitive in identifying response to treatment. The identification of responder definitions for FM clinical trials that include assessments of key symptom and function domains may improve the sensitivity of clinical trials to identify meaningful improvements, leading to improved management of FM.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90281/1/33360_ftp.pd
Measures of fibromyalgia: Fibromyalgia Impact Questionnaire (FIQ), Brief Pain Inventory (BPI), Multidimensional Fatigue Inventory (MFIâ20), Medical Outcomes Study (MOS) Sleep Scale, and Multiple Ability SelfâReport Questionnaire (MASQ)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88107/1/20531_ftp.pd
Chemoenzymatic elaboration of monosaccharides using engineered cytochrome P450_(BM3) demethylases
Polysaccharides comprise an extremely important class of biopolymers
that play critical roles in a wide range of biological processes,
but the synthesis of these compounds is challenging because of
their complex structures. We have developed a chemoenzymatic
method for regioselective deprotection of monosaccharide substrates
using engineered Bacillus megaterium cytochrome P450
(P450_(BM3)) demethylases that provides a highly efficient means
to access valuable intermediates, which can be converted to a
wide range of substituted monosaccharides and polysaccharides.
Demethylases displaying high levels of regioselectivity toward a
number of protected monosaccharides were identified using a
combination of protein and substrate engineering, suggesting that
this approach ultimately could be used in the synthesis of a wide
range of substituted mono- and polysaccharides for studies in
chemistry, biology, and medicine
Separability Criterion for all bipartite Gaussian States
We provide a necessary and sufficient condition for separability of Gaussian
states of bipartite systems of arbitrarily many modes. The condition provides
an operational criterion since it can be checked by simple computation.
Moreover, it allows us to find a pure product-state decomposition of any given
separable Gaussian state. Our criterion is independent of the one based on
partial transposition, and is strictly stronger.Comment: 4 pages, 1 figure (.eps
Feature relative navigation for automous underwater vehicles
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997.Includes bibliographical references (leaves 184-196).by Andrew Arnold Bennett.Ph.D
Calculations of parity nonconserving s-d transitions in Cs, Fr, Ba II, and Ra II
We have performed ab initio mixed-states and sum-over-states calculations of
parity nonconserving (PNC) electric dipole (E1) transition amplitudes between
s-d electron states of Cs, Fr, Ba II, and Ra II. For the lower states of these
atoms we have also calculated energies, E1 transition amplitudes, and
lifetimes. We have shown that PNC E1 transition amplitudes between s-d states
can be calculated to high accuracy. Contrary to the Cs 6s-7s transition, in
these transitions there are no strong cancelations between different terms in
the sum-over-states approach. In fact, there is one dominating term which
deviates from the sum by less than 20%. This term corresponds to an s-p_{1/2}
weak matrix element, which can be calculated to better than 1%, and a
p_{1/2}-d_{3/2} E1 transition amplitude, which can be measured. Also, the s-d
amplitudes are about four times larger than the corresponding s-s transitions.
We have shown that by using a hybrid mixed-states/sum-over-states approach the
accuracy of the calculations of PNC s-d amplitudes could compete with that of
Cs 6s-7s if p_{1/2}-d_{3/2} E1 amplitudes are measured to high accuracy.Comment: 15 pages, 8 figures, submitted to Phys. Rev.
- âŠ