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In cross-country skiing competitions, the choice of pacing strategy is of decisive significance to athletes' performance. A reasonable pacing strategy is essential for athletes to improve their performance. In this paper, the mathematical models of cross-country skiing simulation and pacing optimization are established, including motion model, athlete power output model, and optimization model. The actual competition data of a Chinese athlete in Guyangshu 1.5 km track was compared with the model simulation results. The whole process time error is less than 3%, which verifies the accuracy of the motion and power output model. Gauss pseudo-spectral method is applied to the optimization model. By changing the distribution of athletes' power output, the racing time is minimized under the condition that the total energy output remains unchanged. Compared with the pacing strategy before optimization, the optimized racing time was shortened by 12.6 s, which verifies the effectiveness of the optimization model. Optimized results show that in the first significant uphill section, a recommendation is to use a more conservative strategy, while in the latter half of uphill sections the power output should be increased. [ABSTRACT FROM AUTHOR]

Identity by descent (IBD) sharing is a very important genomic feature in population genetics which can be used to reconstruct recent demographic history. In this paper we provide a framework to estimate IBD sharing for a demographic model called two-population model with migration. We adopt the structured coalescent theory and use a continuous-time Markov jump process {X(t), t ≥ 0} to describe the genealogical process in such model. Then we apply Kolmogorov backward equation to calculate the distribution of coalescence time and develop a formula for estimating the IBD sharing. The simulation studies show that our method to estimate IBD sharing for this demographic model is robust and accurate. [ABSTRACT FROM AUTHOR]

Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including (1) fast cationic polymerization with slow anionic one, (2) fast anionic polymerization with dormant cationic one, and (3) reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory (DFT) calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A "tripedal crow" configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results. [ABSTRACT FROM AUTHOR]

5, when the initial conditions are known, the dynamic trajectory planning problem can be transformed into a series of static optimization problems SP 13,15 sp ; in fact, this process is to transform the two-point boundary value problem corresponding to the continuous first-order necessary condition of the original optimization problem into an initial value problem SP 16 sp ." now reads: "As shown in Fig. 5 SP 15 sp , when the initial conditions are known, the dynamic trajectory planning problem can be transformed into a series of static optimization problems SP 13,16 sp ; in fact, this process is to transform the two-point boundary value problem corresponding to the continuous first-order necessary condition of the original optimization problem into an initial value problem SP 17 sp .". [Extracted from the article]

RNA regulatory elements (RREs) are an important yet relatively under-explored facet of gene regulation. Deciphering the prevalence and functional impact of this post-transcriptional control layer requires technologies for disrupting RREs without perturbing cellular homeostasis. Here we describe genome-engineering based evaluation of RNA regulatory element activity (GenERA), a clustered regularly interspaced short palindromic repeats (CRISPR)- Cas9 platform for in situ high-content functional analysis of RREs. We use GenERA to survey the entire regulatory landscape of a 3'UTR, and apply it in a multiplex fashion to analyse combinatorial interactions between sets of miRNA response elements (MREs), providing strong evidence for cooperative activity. We also employ this technology to probe the functionality of an entire MRE network under cellular homeostasis, and show that highresolution analysis of the GenERA dataset can be used to extract functional features of MREs. This study provides a genome editing-based multiplex strategy for direct functional interrogation of RNA cis-regulatory elements in a native cellular environment. [ABSTRACT FROM AUTHOR]

Increasing gender diversity in the boardroom has been promoted as a way to enhance corporate governance and risk management. This study empirically examines whether boards with more female directors play a role in reducing R&D risk. We first show that female directors help to reduce the positive relationship between R&D investment and future performance volatility. We then report that firms with more gender-diverse boards exhibit a lower adverse effect of R&D on the cost of debt. These results are robust to endogeneity analysis, alternative measures of gender diversity and risky investment, and other sensitivity tests. Overall, our results suggest that female directors improve board effectiveness in risk management with respect to R&D investment. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of acupuncture therapy on the side effect of Etomidate anesthesia and to determine the best timing of acupuncture intervention during Etomidate anesthesia. Methods: Female patients with rectal cancer scheduled to receive radical resection were randomly divided into four groups: a control group (group I), a preoperative acupuncture group (group II), an intraoperative acupuncture group (group III), and a postoperative acupuncture group (group IV), 25 subjects in each group. The levels of serum cortisol, blood glucose, and gastrin of patients were monitored at the following time-points: preoperative (T0, when having entered the operating room), intraoperative (T1, 30 min after skin cutting), the end of operation (T2, after suturing skin), and postoperative (T3, postoperative 24 h). The cases with massive hemorrhage, unsteady vital sign during operation or operation time longer than 5 h were eliminated, and 92 cases were enrolled into the results of the study. Results: The blood sugar in the four groups increased significantly at T2 and T3, compared to T0 ( P<0.05); the blood sugar reached 8.78±1,57) mmol/L at T2 in group, and the increase was statistically significant compared to those of the other groups ( P<0.05). The levels of serum cortisol of all patients were in normal range. Compare to T0, the cortisol level decreased in group I, III, IV at each point, and the decreases were statistically significant ( P<0.05). Compared to the other groups, the cortisol level was increased at T1 and T3 in group II, and the change was statistically significant ( P<0.05). Compared to T0, the gastrin level at T3 increased in group I, III and IV, but decreased in group II, and the changes had statistical significance ( P<0.05). Compared to the other groups, the decrease of gastrin level in group II at T3 was statistically significant ( P<0.05). Conclusion: Acupuncture before operation can keep blood sugar and serum cortisol steady during Etomidate anesthesia and reduce gastrin after Etomidate anesthesia, hence regulating the Etomidate-related stress responses effectively. [ABSTRACT FROM AUTHOR]

The novel method of improving the quality metric of protein microarray image presented in this paper reduces impulse noise by using an adaptive median filter that employs the switching scheme based on local statistics characters; and achieves the impulse detection by using the difference between the standard deviation of the pixels within the filter window and the current pixel of concern. It also uses a top-hat filter to correct the background variation. In order to decrease time consumption, the top-hat filter core is cross structure. The experimental results showed that, for a protein microarray image contaminated by impulse noise and with slow background variation, the new method can significantly increase the signal-to-noise ratio, correct the trends in the background, and enhance the flatness of the background and the consistency of the signal intensity. [ABSTRACT FROM AUTHOR]

An acoustic asymmetric transmission device exhibiting unidirectional transmission property for acoustic waves is extremely desirable in many practical scenarios. Such a unique property may be realized in various configurations utilizing acoustic Zeeman effects in moving media as well as frequency-conversion in passive nonlinear acoustic systems and in active acoustic systems. Here we demonstrate a new acoustic frequency conversion process in a time-varying system, consisting of a rotating blade and the surrounding air. The scattered acoustic waves from this time-varying system experience frequency shifts, which are linearly dependent on the blade's rotating frequency. Such scattering mechanism can be well described theoretically by an acoustic linear time-varying perturbation theory. Combining such time-varying scattering effects with highly efficient acoustic filtering, we successfully develop a tunable acoustic unidirectional device with 20 dB power transmission contrast ratio between two counter propagation directions at audible frequencies. [ABSTRACT FROM AUTHOR]