Multidomain pseudospectral approximations to nonlinear convection-diffusion equations are considered. The schemes are formulated with the Legendre-Galerkin method but the nonlinear term is collocated at the Legendre/C...Multidomain pseudospectral approximations to nonlinear convection-diffusion equations are considered. The schemes are formulated with the Legendre-Galerkin method but the nonlinear term is collocated at the Legendre/Chebyshev-Gauss-Lobatto points inside each subinterval. Appropriate base functions are introduced so that the matrix of the system is sparse, and the method can be implemented efficiently and in parallel. The stability and the optimal rate of convergence of the methods are proved. Numerical results are given for both the single domain and the multidomain methods to make a comparison.展开更多
Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tR...Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tRNA synthetases (aaRS), is an L-shaped molecule whose size in one dimension is similar to that of its cognate aaRS. Crystallographic structures of aaRS/tRNA complexes show that these enzymes use several of their structural domains to interact with their cognate tRNA. This mini review discusses first some aspects of the evolution and of the flexibility of the pentadomain bacterial glutamyl-tRNA synthetase (GluRS) revealed by kinetic and interaction studies of complementary truncated forms, and then illustrates how stable analogues of aminoacyl-AMP intermediates have been used to probe conformational changes in the active sites of Escherichia coli GluRS and of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) of Pseudomonas aeruginosa.展开更多
This study evaluates the physical mechanisms of incident waves as they interact with a porous wavy barrier of finite thickness.A wave-trapping chamber is formed between the thick wavy barrier(TWB)and partially reflect...This study evaluates the physical mechanisms of incident waves as they interact with a porous wavy barrier of finite thickness.A wave-trapping chamber is formed between the thick wavy barrier(TWB)and partially reflecting seawall(PRS).The effect of seabed undulations is incorporated into the wave-trapping analysis of the TWB.The boundary value problem proposed in this study is solved using a multidomain boundary element method within the context of linear potential flow theory.Coefficients such as reflection,runup,horizontal force on PRS,and vertical force on TWB are examined for various structural configurations.The position of seabed undulations is analyzed for four scenarios:i)seabed undulations upwave of the wavy barrier with a trapping chamber,ii)seabed undulations upwave of the wavy barrier without a trapping chamber,iii)seabed undulations underneath the wavy barrier with a trapping chamber,and iv)seabed undulations beneath the wavy barrier without a trapping chamber.The study results are compared with known results to verify their accuracy.The effects of PRS,TWB porosity,trapping chamber,plate thickness,seabed type,and submergence depth on hydrodynamic coefficients are analyzed against relative water depth.The study reveals that the introduction of a porous TWB with a trapping chamber results in minimal hydrodynamic coefficients(reduced reflection and force on a wall)compared to a rigid TWB without a trapping chamber.A comparison of various seabeds is reported for all combinations of TWB with a chamber.The sloping seabed upwave of the barrier with a trapping chamber,20%plate porosity,and 50%wall reflection at an appropriate submergence depth could replace gravity-type breakwaters in deeper waters.This study holds great potential for analyzing wave trapping coefficients by TWB to provide an effective coastal protection system.展开更多
Beef and mutton production has been aided by breeding to integrate allelic diversity for myostatin(MSTN),but a lack of diversity in the MSTN germplasm has limited similar advances in pig farming.Moreover,insurmountabl...Beef and mutton production has been aided by breeding to integrate allelic diversity for myostatin(MSTN),but a lack of diversity in the MSTN germplasm has limited similar advances in pig farming.Moreover,insurmountable challenges with congenital lameness and a dearth of data about the impacts of feed conversion,reproduction,and meat quality in MSTN-edited pigs have also currently blocked progress.Here,in a largest-to-date evaluation of multiple MSTN-edited pig populations,we demonstrated a practical alternative edit-site-based solution that overcomes the major production obstacle of hindlimb weakness.We also provide long-term and multidomain datasets for multiple breeds that illustrate how MSTN-editing can sustainably increase the yields of breed-specific lean meat and the levels of desirable lipids without deleteriously affecting feed-conversion rates or litter size.Apart from establishing a new benchmark for the data scale and quality of genome-edited animal production,our study specifically illustrates how gene-editing site selection profoundly impacts the phenotypic outcomes in diverse genetic back-grounds.展开更多
This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater.The wave interac...This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater.The wave interaction with the H-shaped breakwater is examined by analyzing the wave reflection,transmission,and dissipation coefficients.Additionally,the horizontal wave force coefficients are evaluated to analyze the effectiveness of the horizontal plates when integrated with the main structure.The primary structural parameters directly affect the performance of the composite breakwater and are varied within the feasible range of nondimensional wave numbers,relative spacings,and incident wave angles.This study presents a comparative analysis of the arrangement of the horizontal plates in terms of spacing and inclinations inward and outward to the breakwater using a multidomain boundary element method(BEM).The variation of the structural parameters proposes suitable dimensions for integrated H-shaped breakwater with horizontal plates that provide optimal performance in shallow and deep-water regions.The optimum plate porosity,dimensions of the H-shaped structure,inclinations,and spacing between the plate and breakwater are thoroughly discussed.This study shows that impermeable plates are the excellent means to control the wave force in the intermediate water depth regions than in deep-water regions at resisting wave force.The wave force coefficient on the breakwater is significantly larger than that on the seaside plates.Interestingly,inward-inclined plates perform most efficiently at angles greater than 5°,except in deep-water regions where horizontal plates perform better.In addition,this study noted that regardless of water depth,the outward-inclined plates are the least effective in reflecting the incident wave energy.This study will help plan the layout of suitable composite structures for efficient near-shore and offshore harbor protection according to the site criteria and environmental conditions.展开更多
First-break picking is the key step in seismic data processing for surveying undulate surfaces, and directly infl uences the precision of near-surface modeling and effects of static corrections. The current first-brea...First-break picking is the key step in seismic data processing for surveying undulate surfaces, and directly infl uences the precision of near-surface modeling and effects of static corrections. The current first-break auto-picking methods may fail when the signalto-noise ratio（SNR） is low for seismic data in the undulate area, and require labor and time intensive manual picking. This study develops an improved super-virtual interferometry（SVI） method that combines multichannel and multidomain quality control（MMQC） techniques to achieve auto-picked first breaks. The improved SVI method extends the SVI application to enhance the SNR for near-surface scattered waves for the first time, which allows for the SVI method to adapt to first breaks with complex raypaths by linear combination of refractions and near-surface scattered waves. Methods of inverse and multidomain interferometry are developed to effectively enhance the virtual records extracted by the SVI method. The deconvolution filter for waveforms is used to increase resolution and reduce false picks, while the MMQC technique is designed to auto-correct false picks and increase the stability of auto-picking first breaks. The robust technique developed in this study enables stable processing of large 3D seismic datasets. Higher quality results are obtained using the approach presented in this paper to actual field data from the mountain areas in western China, when compared to some commonly used commercial software.展开更多
Dementia is one of the greatest global challenges for health and social care in the 21st century.Alzheimer’s disease(AD),the most common type of dementia,is by no means an inevitable consequence of growing old.Severa...Dementia is one of the greatest global challenges for health and social care in the 21st century.Alzheimer’s disease(AD),the most common type of dementia,is by no means an inevitable consequence of growing old.Several lifestyle factors may increase,or reduce,an individual’s risk of developing AD.Much has been written over the ages about the benefits of exercise and physical activity.Among the risk factors associated with AD is a low level of physical activity.The relationship between physical and mental health was established several years ago.In this review,we discuss the role of exercise(aerobic and resistance)training as a therapeutic strategy for the treatment and prevention of AD.Older adults who exercise are more likely to maintain cognition.We address the main protective mechanism on brain function modulated by physical exercise by examining both human and animal studies.We will pay especial attention to the potential role of exercise in the modulation of amyloid b turnover,inflammation,synthesis and release of neurotrophins,and improvements in cerebral blood flow.Promoting changes in lifestyle in presymptomatic and predementia disease stages may have the potential for delaying one-third of dementias worldwide.Multimodal interventions that include the adoption of an active lifestyle should be recommended for older populations.展开更多
基金supported by the National Natural Science Foundation of China(No.60874039)the Leading Academic Discipline Project of Shanghai Municipal Education Commission(No.J50101)
文摘Multidomain pseudospectral approximations to nonlinear convection-diffusion equations are considered. The schemes are formulated with the Legendre-Galerkin method but the nonlinear term is collocated at the Legendre/Chebyshev-Gauss-Lobatto points inside each subinterval. Appropriate base functions are introduced so that the matrix of the system is sparse, and the method can be implemented efficiently and in parallel. The stability and the optimal rate of convergence of the methods are proved. Numerical results are given for both the single domain and the multidomain methods to make a comparison.
文摘Many enzymes which catalyze the conversion of large substrates are made of several structural domains belonging to the same polypeptide chain. Transfer RNA (tRNA), one of the substrates of the multidomain aminoacyl-tRNA synthetases (aaRS), is an L-shaped molecule whose size in one dimension is similar to that of its cognate aaRS. Crystallographic structures of aaRS/tRNA complexes show that these enzymes use several of their structural domains to interact with their cognate tRNA. This mini review discusses first some aspects of the evolution and of the flexibility of the pentadomain bacterial glutamyl-tRNA synthetase (GluRS) revealed by kinetic and interaction studies of complementary truncated forms, and then illustrates how stable analogues of aminoacyl-AMP intermediates have been used to probe conformational changes in the active sites of Escherichia coli GluRS and of the nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) of Pseudomonas aeruginosa.
文摘This study evaluates the physical mechanisms of incident waves as they interact with a porous wavy barrier of finite thickness.A wave-trapping chamber is formed between the thick wavy barrier(TWB)and partially reflecting seawall(PRS).The effect of seabed undulations is incorporated into the wave-trapping analysis of the TWB.The boundary value problem proposed in this study is solved using a multidomain boundary element method within the context of linear potential flow theory.Coefficients such as reflection,runup,horizontal force on PRS,and vertical force on TWB are examined for various structural configurations.The position of seabed undulations is analyzed for four scenarios:i)seabed undulations upwave of the wavy barrier with a trapping chamber,ii)seabed undulations upwave of the wavy barrier without a trapping chamber,iii)seabed undulations underneath the wavy barrier with a trapping chamber,and iv)seabed undulations beneath the wavy barrier without a trapping chamber.The study results are compared with known results to verify their accuracy.The effects of PRS,TWB porosity,trapping chamber,plate thickness,seabed type,and submergence depth on hydrodynamic coefficients are analyzed against relative water depth.The study reveals that the introduction of a porous TWB with a trapping chamber results in minimal hydrodynamic coefficients(reduced reflection and force on a wall)compared to a rigid TWB without a trapping chamber.A comparison of various seabeds is reported for all combinations of TWB with a chamber.The sloping seabed upwave of the barrier with a trapping chamber,20%plate porosity,and 50%wall reflection at an appropriate submergence depth could replace gravity-type breakwaters in deeper waters.This study holds great potential for analyzing wave trapping coefficients by TWB to provide an effective coastal protection system.
基金the National Major Transgenic Breeding Project(2008ZX08006-003,2011ZX08006-003,2013ZX08006-003,2014ZX08006-003,and 2016ZX08006-001)the Na-tional Key Basic Research Development Plan(2015CB943100)+1 种基金the Key Projects of the National Natural Science Foundation of China(30830080 and 31330074)China Postdoctoral Foundation Project(2018M631648)。
文摘Beef and mutton production has been aided by breeding to integrate allelic diversity for myostatin(MSTN),but a lack of diversity in the MSTN germplasm has limited similar advances in pig farming.Moreover,insurmountable challenges with congenital lameness and a dearth of data about the impacts of feed conversion,reproduction,and meat quality in MSTN-edited pigs have also currently blocked progress.Here,in a largest-to-date evaluation of multiple MSTN-edited pig populations,we demonstrated a practical alternative edit-site-based solution that overcomes the major production obstacle of hindlimb weakness.We also provide long-term and multidomain datasets for multiple breeds that illustrate how MSTN-editing can sustainably increase the yields of breed-specific lean meat and the levels of desirable lipids without deleteriously affecting feed-conversion rates or litter size.Apart from establishing a new benchmark for the data scale and quality of genome-edited animal production,our study specifically illustrates how gene-editing site selection profoundly impacts the phenotypic outcomes in diverse genetic back-grounds.
基金the partial support from the Ministry of Ports,Shipping and Waterways,Government of India,through the research grant no.DW/01013(13)/2/2021.
文摘This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater.The wave interaction with the H-shaped breakwater is examined by analyzing the wave reflection,transmission,and dissipation coefficients.Additionally,the horizontal wave force coefficients are evaluated to analyze the effectiveness of the horizontal plates when integrated with the main structure.The primary structural parameters directly affect the performance of the composite breakwater and are varied within the feasible range of nondimensional wave numbers,relative spacings,and incident wave angles.This study presents a comparative analysis of the arrangement of the horizontal plates in terms of spacing and inclinations inward and outward to the breakwater using a multidomain boundary element method(BEM).The variation of the structural parameters proposes suitable dimensions for integrated H-shaped breakwater with horizontal plates that provide optimal performance in shallow and deep-water regions.The optimum plate porosity,dimensions of the H-shaped structure,inclinations,and spacing between the plate and breakwater are thoroughly discussed.This study shows that impermeable plates are the excellent means to control the wave force in the intermediate water depth regions than in deep-water regions at resisting wave force.The wave force coefficient on the breakwater is significantly larger than that on the seaside plates.Interestingly,inward-inclined plates perform most efficiently at angles greater than 5°,except in deep-water regions where horizontal plates perform better.In addition,this study noted that regardless of water depth,the outward-inclined plates are the least effective in reflecting the incident wave energy.This study will help plan the layout of suitable composite structures for efficient near-shore and offshore harbor protection according to the site criteria and environmental conditions.
基金supported by the National Basic Research Program of China(No.2013CB228602)the National Science and Technology Major Project of China(No.2011ZX05004-003)the National High Tech Research Program of China(No.2013AA064202)
文摘First-break picking is the key step in seismic data processing for surveying undulate surfaces, and directly infl uences the precision of near-surface modeling and effects of static corrections. The current first-break auto-picking methods may fail when the signalto-noise ratio（SNR） is low for seismic data in the undulate area, and require labor and time intensive manual picking. This study develops an improved super-virtual interferometry（SVI） method that combines multichannel and multidomain quality control（MMQC） techniques to achieve auto-picked first breaks. The improved SVI method extends the SVI application to enhance the SNR for near-surface scattered waves for the first time, which allows for the SVI method to adapt to first breaks with complex raypaths by linear combination of refractions and near-surface scattered waves. Methods of inverse and multidomain interferometry are developed to effectively enhance the virtual records extracted by the SVI method. The deconvolution filter for waveforms is used to increase resolution and reduce false picks, while the MMQC technique is designed to auto-correct false picks and increase the stability of auto-picking first breaks. The robust technique developed in this study enables stable processing of large 3D seismic datasets. Higher quality results are obtained using the approach presented in this paper to actual field data from the mountain areas in western China, when compared to some commonly used commercial software.
基金TagedPThis work was supported by the following grants:Instituto de Salud Carlos III and co-funded by FEDER(Grant number PIE15/00013)SAF2016-75508-R from the Spanish Ministry of Education and Science(MEC)+2 种基金CB16/10/00435(CIBERFES)PROMETEOII2014/056 from Conselleria,de Sanitat de la Generalitat Valenciana and EU Funded CM1001 and FRAILOMICHEALTH.2012.2.1.1-2ADVANTAGE-724099 Join Action(HP-JA)3rd EU Health Programme and DIALBFRAIL-LATAM(825546 H2020-SC1-BHC).
文摘Dementia is one of the greatest global challenges for health and social care in the 21st century.Alzheimer’s disease(AD),the most common type of dementia,is by no means an inevitable consequence of growing old.Several lifestyle factors may increase,or reduce,an individual’s risk of developing AD.Much has been written over the ages about the benefits of exercise and physical activity.Among the risk factors associated with AD is a low level of physical activity.The relationship between physical and mental health was established several years ago.In this review,we discuss the role of exercise(aerobic and resistance)training as a therapeutic strategy for the treatment and prevention of AD.Older adults who exercise are more likely to maintain cognition.We address the main protective mechanism on brain function modulated by physical exercise by examining both human and animal studies.We will pay especial attention to the potential role of exercise in the modulation of amyloid b turnover,inflammation,synthesis and release of neurotrophins,and improvements in cerebral blood flow.Promoting changes in lifestyle in presymptomatic and predementia disease stages may have the potential for delaying one-third of dementias worldwide.Multimodal interventions that include the adoption of an active lifestyle should be recommended for older populations.
