2,514 research outputs found
Computational codon optimization of synthetic gene for protein expression
10.1186/1752-0509-6-134BMC Systems Biology6
Universal conductance fluctuations in non-integer dimensions
We propose an Ansatz for Universal conductance fluctuations in continuous
dimensions from 0 up to 4. The Ansatz agrees with known formulas for integer
dimensions 1, 2 and 3, both for hard wall and periodic boundary conditions. The
method is based solely on the knowledge of energy spectrum and standard
assumptions. We also study numerically the conductance fluctuations in 4D
Anderson model, depending on system size L and disorder W. We find a small
plateau with a value diverging logarithmically with increasing L. Universality
gets lost just in 4D.Comment: 4 pages, 4 figures submitted to Phys. Rev.
Improving propensity score weighting using machine learning
Machine learning techniques such as classification and regression trees (CART) have been suggested as promising alternatives to logistic regression for the estimation of propensity scores. The authors examined the performance of various CART-based propensity score models using simulated data. Hypothetical studies of varying sample sizes (n=500, 1000, 2000) with a binary exposure, continuous outcome, and 10 covariates were simulated under seven scenarios differing by degree of non-linear and non-additive associations between covariates and the exposure. Propensity score weights were estimated using logistic regression (all main effects), CART, pruned CART, and the ensemble methods of bagged CART, random forests, and boosted CART. Performance metrics included covariate balance, standard error, per cent absolute bias, and 95 per cent confidence interval (CI) coverage. All methods displayed generally acceptable performance under conditions of either non-linearity or non-additivity alone. However, under conditions of both moderate non-additivity and moderate non-linearity, logistic regression had subpar performance, whereas ensemble methods provided substantially better bias reduction and more consistent 95 per cent CI coverage. The results suggest that ensemble methods, especially boosted CART, may be useful for propensity score weighting
Performance analysis on transfer platforms in frame bridge based automated container terminals
10.1155/2013/593847Mathematical Problems in Engineering2013
Associations between job satisfaction, job characteristics, and acoustic environment in open-plan offices
© 2020 Elsevier Ltd This study aimed to investigate the associations between physical acoustic factors, job characteristics, and job satisfaction. Acoustic measurements and questionnaire surveys were conducted in 12 open-plan offices. Active noise levels (LAeq,8-hour), reverberation time (T20), and speech privacy-related measures such as D2,S and Lp,A,S,4m were measured at each office. A total of 324 employees then completed the online questionnaire surveys. The questionnaire assessed perceived speech privacy, noise disturbance, job characteristics, and job satisfaction. The measures of job characteristics involved skill variety, task identity, task significance, and autonomy. The results showed that active noise level (LAeq,8-hour) was negatively correlated with job satisfaction. Also, job satisfaction showed a negative correlation with speech privacy, whereas the relationship between job satisfaction and noise disturbance was not significant. It was also observed that the relationship between task identity and job satisfaction was moderated by the active noise level and speech privacy
Cosmological Histories for the New Variables
Histories and measures for quantum cosmology are investigated through a
quantization of the Bianchi IX cosmology using path integral techniques. The
result, derived in the context of Ashtekar variables, is compared with earlier
work. A non-trivial correction to the measure is found, which may dominate the
classical potential for universes on the Planck scale.Comment: 14, CGPG-94/2-
Natural Color Transparency in High Energy (p,pp) Reactions
New parameter free calculations including a variety of necessary kinematic
and dynamic effects show that the results of BNL measurements are
consistent with the expectations of color transparency.Comment: latex file, 13 pages, 4 figures appended as ps files, look for "cut
here ..." 1993 Univ. of Washington preprint 404427-00-N93-1
Evidence for particle-hole excitations in the triaxial strongly-deformed well of ^{163}Tm
Two interacting, strongly-deformed triaxial (TSD) bands have been identified
in the Z = 69 nucleus ^{163}Tm. This is the first time that interacting TSD
bands have been observed in an element other than the Z = 71 Lu nuclei, where
wobbling bands have been previously identified. The observed TSD bands in
^{163}Tm appear to be associated with particle-hole excitations, rather than
wobbling. Tilted-Axis Cranking (TAC) calculations reproduce all experimental
observables of these bands reasonably well and also provide an explanation for
the presence of wobbling bands in the Lu nuclei, and their absence in the Tm
isotopes.Comment: 13 pages, 7 figure
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