Is it the time to reconsider the choice of valves for cardiac surgery： mechanical or bioprosthetic？

Valvular heart disease is a pathologic process involving one or more of the four valves(aortic,pulmonary,mitral and tricuspid)of the heart typified by stenosis or regurgitation and leading to patient symptoms.The most common causes are tissue degeneration,rheumatic fever and congenital heart diseases.Aortic valve replacement(AVR)using either mechanical or bioprosthetic(tissue)valves via open-heart surgical

LARGE TIME STEP GENERALIZATION OF RANDOM CHOICE FINITE DIFFERENCE SCHEME FOR HYPERBOLIC CONSERVATION LAWS

A natural generalization of random choice finite difference scheme of Harten and Lax for Courant number larger than 1 is obtained. We handle interactions between neighboring Riemann solvers by linear superposition of their conserved quantities. We show consistency of the scheme for arbitrarily large Courant numbers. For scalar problems the scheme is total variation diminishing.A brief discussion is given for entropy condition.

Effects of Rhodiola rosea supplementation on mental performance,physical capacity,and oxidative stress biomarkers in healthy men

Purpose： The objective of this study was to investigate the effects of chronic Rhodiola rosea （R. rosea） supplementation on mental and physical performance, as well as hormonal and oxidative stress biomarkers. Methods： Twenty-six healthy male students received either R. rosea extract （600 mg/day; RR） or placebo （PL） in a randomized double-blind trial. Prior to supplementation （Term I） and following 4 weeks of supplementation （Term II）, the students underwent psychomotor tests for simple and choice reaction time, included in the Vienna Test System. Also, the subjects performed VO2peak test. Blood samples were obtained before and after the test to measure the hormonal profile （cortisol, testosterone, and growth hormone）, as well as the biomarkers of oxidative stress （lipid hydroperoxides, total antioxidant capacity, and superoxide dismutase） and muscle damage （creatine kinase）. Results： R. rosea ingestion shortened reaction time and total response time. Moreover, a greater relative increase in the number of correct responses was observed in RR group as compared to the PL group. No changes in endurance exercise capacity and hormonal profile were observed after R. rosea ingestion. R. rosea ingestion raised plasma total antioxidant capacity. It did not, however, affect other measured parameters. Conclusion： Chronic R. rosea ingestion does not affect physical performance, but can improve the results of some psychomotor tests （simple and choice reaction time） in young, healthy, and physically active men. The improvements in mental performance, however, at least in our study, seem not to be related to changes in cortisol release or antioxidant activity of R. rosea extract. Thus, the specific mechanisms responsible for these effects still need to be elucidated.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Time to Make a Choice

How should the international community overcome the current stalemate in the North Korean nuclear crisis? North Korea conducted its second underground nuclear test on May 25, sparking a strong reaction from the international community. This was in sharp contrast to less than a year ago when the

Behavior Insights for an Incentive-Based Active Demand Management Platform

Most current Travel Demand Management(TDM)programs such as vanpooling,ridesharing,or transit focus on managing travel demand of specific groups of commuters but are limited in effectively managing demand for automobile drivers,who are unable or unwilling to participate in such programs.This paper highlights results from a pilot field study conducted in a large west coast city experiencing major traffic congestion,and documents results of the use of an incentive-based active demand management(ADM)system focusing on automobile commuters.The system,called“Metropia,”predicts future traffic conditions,applies a proprietary routing algorithm to find time-dependent shortest paths for different departure times,and,based on user request,provides automobile travelers with multiple departure times and route choices.Each of these travel choices are assigned points values,with higher points(and thus more valuable rewards)available for travelling during off-peak times and less congested routes,and lower points available for peak traffic travel times.The goal of this ADM system is to improve traffic flow and commuter travel times citywide,alleviating heavily congested areas without the use of new roadway construction by incentivizing travelers to change their travel behavior and avoid traffic congestion.The level of rewards points available to users(commuters)by the system depends on the travelers’behavioral change degree and their contributions to traffic congestion alleviation.This system was implemented in Los Angeles,Calif.,USA,as a small scale pilot field study carried out beginning April 2013 and lasting for 10 weeks.Results from this field study show the system is able to accurately predict travel time with Relative Mean Absolute Error(RMAE)as low as 15.20%.Significant travel behavior changes were observed which validate the concept of using incentives to influence people’s travel behavior.Furthermore,field study results show 20%travel time can be saved for people who changed their travel behavior.