Too much screen time is bad for your brain and body.It can also waste your time.So,try to spend less time on scree ns.Changing habits is not easy,but you can do it.Use an app to track your time on your smartphone.Do y...Too much screen time is bad for your brain and body.It can also waste your time.So,try to spend less time on scree ns.Changing habits is not easy,but you can do it.Use an app to track your time on your smartphone.Do you waste a lot of time on some ofyour phone apps?Take them off or set time limits for them.Less screen time means more free time for other things.Go hiking,visit a museum or try a new hobby.Use your phone less and appreciate life more.展开更多
Since children, as a rule, have more free time than adults, it is adults＇ responsibility to provide children with a chance to spend the time of relaxation, play, and fun in a beneficial way. Unfortunately, children＇...Since children, as a rule, have more free time than adults, it is adults＇ responsibility to provide children with a chance to spend the time of relaxation, play, and fun in a beneficial way. Unfortunately, children＇s spare time is nowadays very frequently organized for the sake of brushing up children＇s knowledge, skills, and competences, which is accomplished by means of escalating extra-curriculum activities. When expressed by teacher and parents, these ambition-related attitudes pave the way for the disappearance of children＇s personal interests and motivations to perform complicated tasks which are perceived as unwanted or obscure by the affected children themselves. This form of adults＇ behavior may lead to the feelings of frustration, stress, demotivation, or rebellion on behalf of their children. The said emotional states, especially in relation to the lack of spontaneous play, give rise to serious psychic dysfunctions, and the instability of children＇s psychic balance. It may also pave the way for various forms of destructive behavior that mostly characterize children of younger school age who are about to start schooling.展开更多
Caregivers who contribute to health care of their patients are significantly more likely to experience emotional difficulty,physical difficulty,and financial difficulty,than caregivers who do not contribute.This study...Caregivers who contribute to health care of their patients are significantly more likely to experience emotional difficulty,physical difficulty,and financial difficulty,than caregivers who do not contribute.This study aimed to examine the effects of free time on health-related quality of life among elderly caregivers of dementia patients.In the intervention group,caregivers set aside free time every 30 minutes three times a week,while continuing to care for patients.During the free time,caregivers were free to spend time at home and do whatever they wanted.The control group received only usual care.The intervention period was six months.The Vitality subscale score of the SF-36 decreased significantly in the intervention group,despite more than half(57.1%)of participants showing improvements or no change in the rank of this subscale relative to baseline,as assessed by the Wilcoxon signed-rank test(not significant).Caregivers indicated that daily caregiving resulted in an accumulation of physical fatigue,and they continued to have little mental leeway.Caregivers also had difficulty securing free time,which may have hindered improvements to their vitality.There is a need to develop a home-based program that can alleviate caregiver stress and improve their quality of life.展开更多
Many drinking water treatment plants in the U.S. have switched from chlorination to chloramination to lower levels of regulated trihalomethane(THM) and haloacetic acid(HAA) disinfection byproducts(DBPs) in drinking wa...Many drinking water treatment plants in the U.S. have switched from chlorination to chloramination to lower levels of regulated trihalomethane(THM) and haloacetic acid(HAA) disinfection byproducts(DBPs) in drinking water and meet the current regulations. However, chloramination can also produce other highly toxic/carcinogenic, unregulated DBPs: iodoacids, iodo-THMs, and N-nitrosodimethylamine(NDMA). In practice, chloramines are generated by the addition of chlorine with ammonia, and plants use varying amounts of free chlorine contact time prior to ammonia addition to effectively kill pathogens and meet DBP regulations. However, iodo-DBPs and nitrosamines are generally not considered in this balancing of free chlorine contact time. The goal of our work was to determine whether an optimal free chlorine contact time could be established in which iodo-DBPs and NDMA could be minimized, while keeping regulated THMs and HAAs below their regulatory limits. The effect of free chlorine contact time was evaluated for the formation of six iodo-trihalomethanes(iodo-THMs), six iodo-acids, and NDMA during the chloramination of drinking water. Ten different free chlorine contact times were examined for two source waters with different dissolved organic carbon(DOC) and bromide/iodide. For the low DOC water at pH 7 and 8, an optimized free chlorine contact time of up to 1 h could control regulated THMs and HAAs, as well as iodo-DBPs and NDMA. For the high DOC water, a free chlorine contact time of 5 min could control iodo-DBPs and NDMA at both p Hs, but the regulated DBPs could exceed the regulations at pH 7.展开更多
Errors due to split time stepping are discussed for an explicit free–surface ocean model. In commonly used split time stepping, the way of time integration for the barotropic momentum equation is not compatible with ...Errors due to split time stepping are discussed for an explicit free–surface ocean model. In commonly used split time stepping, the way of time integration for the barotropic momentum equation is not compatible with that of the baroclinic one. The baroclinic equation has three–time–level structure because of leapfrog scheme. The barotropic one, however, has two–time–level structure when represented in terms of the baroclinic time level, on which the baroclinic one is integrated. This incompatibility results in the splitting errors as shown in this paper. The proper split time stepping is therefore proposed in such a way that the compatibility is kept between the barotropic and baroclinic equations. Its splitting errors are shown extremely small, so that it is particularly relevant to long–term integration for climate studies. It is applied to a free–surface model for the North Pacific Ocean.展开更多
This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from s...This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from six plants of sugarcane ROC22, which had been confirmed RSD-positive by detecting the sugarcane juice, by employing the sugarcane seedlings production protocol. Real-time fluorescence quantitative PCR was used to detect RSD pathogens in tissue culture sam- pies. The results showed that target fragment of RSD pathogens was not found in all 10 samples in real-time fluorescence quantitative PCR, with the Ct values of 37 - 39. The healthy tissue culture sugarcane seedlings do not carry RSD pathogens, indicating that adopting healthy seedcane seedlings production technique could thoroughly get rid of RSD pathogens.展开更多
针对传统温度控制系统在实时性、精度和噪声处理方面存在的局限性,提出采用开源实时操作系统(Free Real Time Operating System,FreeRTOS)对任务调度优化的设计方案。通过引入增量比例积分微分控制(Proportional-Integral-Derivative Co...针对传统温度控制系统在实时性、精度和噪声处理方面存在的局限性,提出采用开源实时操作系统(Free Real Time Operating System,FreeRTOS)对任务调度优化的设计方案。通过引入增量比例积分微分控制(Proportional-Integral-Derivative Control,PID)算法、滑动均值滤波器和牛顿-拉夫逊法,提升采集温度的准确性和系统的响应速度,提高温度控制的精确度和实时响应能力,以满足相关行业对温度条件的严格需求。通过优化任务调度、控制算法和数据处理方法,本系统有效降低了温度波动和控制误差,且采集到的温度精度高达±0.005,有效提高了系统的实时性,温度稳定时间提升超过300%,适用于需要高精度和快速响应的现代无人机温度控制应用场景。展开更多
The present paper deals with the numerical solution of time-fractional partial differential equations using the element-free Galerkin （EFG） method, which is based on the moving least-square approximation. Compared w...The present paper deals with the numerical solution of time-fractional partial differential equations using the element-free Galerkin （EFG） method, which is based on the moving least-square approximation. Compared with numerical methods based on meshes, the EFG method for time-fractional partial differential equations needs only scattered nodes instead of meshing the domain of the problem. It neither requires element connectivity nor suffers much degradation in accuracy when nodal arrangements are very irregular. In this method, the first-order time derivative is replaced by the Caputo fractional derivative of order α（0 〈 α≤ 1）. The Galerkin weak form is used to obtain the discrete equations, and the essential boundary conditions are enforced by the penalty method. Several numerical examples are presented and the results we obtained are in good agreement with the exact solutions.展开更多
This paper studies the capacity issues of a wireless communication system that implements single channel full duplex(SCFD) communication at the base station(BS), thereby the mobile stations share the channel via time ...This paper studies the capacity issues of a wireless communication system that implements single channel full duplex(SCFD) communication at the base station(BS), thereby the mobile stations share the channel via time division duplex(TDD). The system makes use of the same setup as has been used in previous studies of SCFD, but unlike these previous systems, the new system uses water-filling to maximize the spectral efficiency of the uplink channel. The concept of a free window is introduced to the duplex model for measuring, intuitively, the effective bandwidth of the bi-directional communication. The capacity gain is calculated and numerical results show the advantage of the proposed system over that of conventional TDD.展开更多
文摘Too much screen time is bad for your brain and body.It can also waste your time.So,try to spend less time on scree ns.Changing habits is not easy,but you can do it.Use an app to track your time on your smartphone.Do you waste a lot of time on some ofyour phone apps?Take them off or set time limits for them.Less screen time means more free time for other things.Go hiking,visit a museum or try a new hobby.Use your phone less and appreciate life more.
文摘Since children, as a rule, have more free time than adults, it is adults＇ responsibility to provide children with a chance to spend the time of relaxation, play, and fun in a beneficial way. Unfortunately, children＇s spare time is nowadays very frequently organized for the sake of brushing up children＇s knowledge, skills, and competences, which is accomplished by means of escalating extra-curriculum activities. When expressed by teacher and parents, these ambition-related attitudes pave the way for the disappearance of children＇s personal interests and motivations to perform complicated tasks which are perceived as unwanted or obscure by the affected children themselves. This form of adults＇ behavior may lead to the feelings of frustration, stress, demotivation, or rebellion on behalf of their children. The said emotional states, especially in relation to the lack of spontaneous play, give rise to serious psychic dysfunctions, and the instability of children＇s psychic balance. It may also pave the way for various forms of destructive behavior that mostly characterize children of younger school age who are about to start schooling.
文摘Caregivers who contribute to health care of their patients are significantly more likely to experience emotional difficulty,physical difficulty,and financial difficulty,than caregivers who do not contribute.This study aimed to examine the effects of free time on health-related quality of life among elderly caregivers of dementia patients.In the intervention group,caregivers set aside free time every 30 minutes three times a week,while continuing to care for patients.During the free time,caregivers were free to spend time at home and do whatever they wanted.The control group received only usual care.The intervention period was six months.The Vitality subscale score of the SF-36 decreased significantly in the intervention group,despite more than half(57.1%)of participants showing improvements or no change in the rank of this subscale relative to baseline,as assessed by the Wilcoxon signed-rank test(not significant).Caregivers indicated that daily caregiving resulted in an accumulation of physical fatigue,and they continued to have little mental leeway.Caregivers also had difficulty securing free time,which may have hindered improvements to their vitality.There is a need to develop a home-based program that can alleviate caregiver stress and improve their quality of life.
文摘Many drinking water treatment plants in the U.S. have switched from chlorination to chloramination to lower levels of regulated trihalomethane(THM) and haloacetic acid(HAA) disinfection byproducts(DBPs) in drinking water and meet the current regulations. However, chloramination can also produce other highly toxic/carcinogenic, unregulated DBPs: iodoacids, iodo-THMs, and N-nitrosodimethylamine(NDMA). In practice, chloramines are generated by the addition of chlorine with ammonia, and plants use varying amounts of free chlorine contact time prior to ammonia addition to effectively kill pathogens and meet DBP regulations. However, iodo-DBPs and nitrosamines are generally not considered in this balancing of free chlorine contact time. The goal of our work was to determine whether an optimal free chlorine contact time could be established in which iodo-DBPs and NDMA could be minimized, while keeping regulated THMs and HAAs below their regulatory limits. The effect of free chlorine contact time was evaluated for the formation of six iodo-trihalomethanes(iodo-THMs), six iodo-acids, and NDMA during the chloramination of drinking water. Ten different free chlorine contact times were examined for two source waters with different dissolved organic carbon(DOC) and bromide/iodide. For the low DOC water at pH 7 and 8, an optimized free chlorine contact time of up to 1 h could control regulated THMs and HAAs, as well as iodo-DBPs and NDMA. For the high DOC water, a free chlorine contact time of 5 min could control iodo-DBPs and NDMA at both p Hs, but the regulated DBPs could exceed the regulations at pH 7.
基金Hundred Talent Program of Chinese Academy of Sciences under Grant No. 0300YQ000101. Partly supported by the National Natural Sci
文摘Errors due to split time stepping are discussed for an explicit free–surface ocean model. In commonly used split time stepping, the way of time integration for the barotropic momentum equation is not compatible with that of the baroclinic one. The baroclinic equation has three–time–level structure because of leapfrog scheme. The barotropic one, however, has two–time–level structure when represented in terms of the baroclinic time level, on which the baroclinic one is integrated. This incompatibility results in the splitting errors as shown in this paper. The proper split time stepping is therefore proposed in such a way that the compatibility is kept between the barotropic and baroclinic equations. Its splitting errors are shown extremely small, so that it is particularly relevant to long–term integration for climate studies. It is applied to a free–surface model for the North Pacific Ocean.
基金Supported by Special Funds for Basic Scientific Research of Guangxi Sugarcane Research Institute(G2009006,G2010006,G2009015)Sci-tech Research and Development Program of Guangxi Academy of Agricultural Sciences(200805)
文摘This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from six plants of sugarcane ROC22, which had been confirmed RSD-positive by detecting the sugarcane juice, by employing the sugarcane seedlings production protocol. Real-time fluorescence quantitative PCR was used to detect RSD pathogens in tissue culture sam- pies. The results showed that target fragment of RSD pathogens was not found in all 10 samples in real-time fluorescence quantitative PCR, with the Ct values of 37 - 39. The healthy tissue culture sugarcane seedlings do not carry RSD pathogens, indicating that adopting healthy seedcane seedlings production technique could thoroughly get rid of RSD pathogens.
文摘针对传统温度控制系统在实时性、精度和噪声处理方面存在的局限性,提出采用开源实时操作系统(Free Real Time Operating System,FreeRTOS)对任务调度优化的设计方案。通过引入增量比例积分微分控制(Proportional-Integral-Derivative Control,PID)算法、滑动均值滤波器和牛顿-拉夫逊法,提升采集温度的准确性和系统的响应速度,提高温度控制的精确度和实时响应能力,以满足相关行业对温度条件的严格需求。通过优化任务调度、控制算法和数据处理方法,本系统有效降低了温度波动和控制误差,且采集到的温度精度高达±0.005,有效提高了系统的实时性,温度稳定时间提升超过300%,适用于需要高精度和快速响应的现代无人机温度控制应用场景。
基金Project supported by the National Natural Science Foundation of China(Grant No.11072117)the Natural Science Foundationof Zhejiang Province,China(Grant Nos.Y6110007and Y6110502)the K.C.Wong Magna Fund in Ningbo University,China
文摘The present paper deals with the numerical solution of time-fractional partial differential equations using the element-free Galerkin （EFG） method, which is based on the moving least-square approximation. Compared with numerical methods based on meshes, the EFG method for time-fractional partial differential equations needs only scattered nodes instead of meshing the domain of the problem. It neither requires element connectivity nor suffers much degradation in accuracy when nodal arrangements are very irregular. In this method, the first-order time derivative is replaced by the Caputo fractional derivative of order α（0 〈 α≤ 1）. The Galerkin weak form is used to obtain the discrete equations, and the essential boundary conditions are enforced by the penalty method. Several numerical examples are presented and the results we obtained are in good agreement with the exact solutions.
基金supported by the HongKong, Macao and Taiwan Science & Technology Cooperation Program of China (Grant no. 2015DFT10170)the Beijing Higher Education Young Elite Teacher Project
文摘This paper studies the capacity issues of a wireless communication system that implements single channel full duplex(SCFD) communication at the base station(BS), thereby the mobile stations share the channel via time division duplex(TDD). The system makes use of the same setup as has been used in previous studies of SCFD, but unlike these previous systems, the new system uses water-filling to maximize the spectral efficiency of the uplink channel. The concept of a free window is introduced to the duplex model for measuring, intuitively, the effective bandwidth of the bi-directional communication. The capacity gain is calculated and numerical results show the advantage of the proposed system over that of conventional TDD.
