183 research outputs found
Updatings of the risk attitude parameter with different values of parameter <i>σ</i>.
<p>A larger <i>σ</i>-value corresponds to a larger change rate of .</p
Evolution of the system with endogenous risk attitudes (<i>σ</i> = 0.9).
<p>Fig 3(a)~3(d) shows the influences of parameters <i>α</i>, <i>β</i> and <i>θ</i> on both steady state and evolution process of the dynamic system.</p
The effects of traveler risk-taking behaviors on system evolution processes.
<p>Fig 4(a) and 4(b) compare the effect difference between risk aversion and risk proneness attitudes. Fig 4(c) and 4(d) show the influences of parameter σ on both fluctuation function Θ<sup><i>t</i></sup> and endogenous risk attitude .</p
Notions and the corresponding definitions.
<p>Notions and the corresponding definitions.</p
Comparison of effects between two different risk attitude evolution schemas.
<p>Fig 5(a) corresponds to the case of endogenous risk attitudes, and Fig 5(b) corresponds to the case of exogenous risk attitudes.</p
Transient Absorption Spectroscopy of Excitons in an Individual Suspended Metallic Carbon Nanotube
We
present femtosecond transient absorption measurements of individual
metallic single-wall carbon nanotubes (SWNTs) to elucidate environmental
effects on their spectroscopy and dynamics. Isolated suspended SWNTs
were located using atomic force microscopy, and Raman spectroscopy
was employed to determine the chiral index of select nanotubes. Transient
absorption spectra of the SWNTs were obtained by recording transient
absorption images at different probe wavelengths. This unique experimental
approach removes sample heterogeneity in ultrafast measurements of
these complex materials and provides a direct means to unravel the
role of the substrate. The results show a ∼40 meV red shift
of the lowest exciton transition, which is attributed to dielectric
screening effects by the substrate. Energy relaxation in individual
metallic nanotubes was observed with decay constants of a few hundred
fs and about 10 ps. We attributed the fast and slow decay components
to carrier scattering by optical and acoustic phonons, respectively
Comparison of methods in scenario one.
Daily incidence (A) was obtained based on the assumptions that the number of initial cases was 2, the serial interval exhibited a lognormal distribution with a mean and variance of 8 and 9, respectively, and a constant R before (R1 = 2.5) and after (R2 = 0.9) a control measure on day 40. The results of serial interval obtained by our method and White et al method (B). The results of instantaneous reproductive number obtained by all methods (C). The red dashed lines show the ground truth. ΔRt, Δμ, and Δσ (D). The blue lines show the estimates, and the dark lines denote the mean values for 100 simulations. ns: no significant difference, ***: P<0.001.</p
Prior information of parameters for MCMC method based on MATLAB toolbox.
Prior information of parameters for MCMC method based on MATLAB toolbox.</p
An example illustrating the workflow of our method.
The time series of daily incidence (A) was simulated according to the conditions of scenario one. Using the BIC (B), the number of data points and serial interval distribution were determined, and the serial interval (C) and instantaneous reproductive number (D) were obtained. The MCMC method (E) was then used to generate the distribution of the serial interval (F) and instantaneous reproductive number (G). BIC: Bayesian information criterion; MCMC: Markov Chain Monte Carlo.</p
Application of our method to seven historical epidemics.
The first column shows daily epidemic curves (from top to bottom) for the pandemic influenza in Boonah, 1918; the pandemic influenza in Cumberland, 1918; the smallpox in Kosovo, February–April 1972; the SARS in Hong Kong, February–June 2003; the COVID-19 in Hunan, 2020; the COVID-19 in Chongqing, 2020; and HFMD in Wenzhou, 2010–2011. The second and third columns show estimates of the serial interval p and instantaneous reproductive number Rt, respectively. The red lines and light red area, the blue lines, the green lines and the light green area in the middle and right columns denote the estimates obtained using our method, White et al method and Cori et al method, respectively. The dark dashed lines represent the threshold of one, and the red arrow denotes the onset of strict measures.</p
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