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An Improved Method for Approximating the Infinite-Horizon Value Function of the Discrete-Time Switched LQR Problem

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Journal of Systems science & Complexity 2024年第1期37卷 22-39页

作者： HOU Tan LI Yuanlong LIN Zongli Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240China Charles L.brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904-4743USA

This paper considers the problem of approximating the infinite-horizon value function of the discrete-time switched LQR *** particular,the authors propose a new value iteration method to generate a sequence of monotonically decreasing functions that converges exponentially to the value *** method facilitates us to use coarse approximations resulting from faster but less accurate algorithms for further value iteration,and thus,the proposed approach is capable of achieving a better approximation for a given computation time compared with the existing *** numerical examples are presented in this paper to illustrate the effectiveness of the proposed method.

关键词： Optimal control switched linear systems switched LQR problem.

Identification of novel small-molecule inhibitors of SARS-CoV-2 by chemical genetics

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Acta Pharmaceutica Sinica B 2024年第9期14卷 4028-4044页

作者： Chris Chun-Yiu Chan Qian Guo Jasper Fuk-Woo Chan Kaiming Tang Jian-Piao Cai Kenn Ka-Heng Chik Yixin Huang Mei Dai Bo Qin Chon Phin Ong Allen Wing-Ho Chu Wan-Mui Chan Jonathan Daniel Ip Lei Wen Jessica Oi-Ling Tsang Tong-Yun Wang Yubin Xie Zhenzhi Qin Jianli Cao Zi-Wei Ye Hin Chu Kelvin Kai-Wang To Xing-Yi Ge Tao Ni Dong-Yan Jin Sheng Cui Kwok-Yung Yuen Shuofeng Yuan State Key Laboratory of Emerging Infectious Diseases Carol Yu Centre for InfectionDepartment of MicrobiologySchool of Clinical MedicineLi Ka Shing Faculty of Medicinethe University of Hong KongPokfulamHong Kong SAR 999077China Department of Infectious Diseases and Microbiology the University of Hong Kong-Shenzhen HospitalShenzhen 518000China Centre for Virology Vaccinology and TherapeuticsHong Kong Science and Technology ParkHong Kong SAR 999077China Academician Workstation of Hainan Province Hainan Medical University-the University of Hong Kong Joint Laboratory of Tropical Infectious DiseasesHaikou 571100China School of Biomedical sciences Li Ka Shing Faculty of Medicinethe University of Hong KongPokfulamHong Kong SAR 999077China NHC Key Laboratory of Systems Biology of Pathogens Institute of Pathogen Biology Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China College of Biology Hunan Provincial Key Laboratory of Medical VirologyHunan UniversityChangsha 410082China

There are only eight approved small molecule antiviral drugs for treating *** them,four are nucleotide analogues(remdesivir,JT001,molnupiravir,and azvudine),while the other four are protease inhibitors(nirmatrelvir,ensitrelvir,leritrelvir,and simnotrelvir-ritonavir).Antiviral resistance,unfavourable drug‒drug interaction,and toxicity have been reported in previous *** there is a dearth of new treatment options for *** this work,a three-tier cell-based screening was employed to identify novel compounds with anti-SARS-CoV-2 *** compound,designated 172,demonstrated broad-spectrum antiviral activity against multiple human pathogenic coronaviruses and different SARS-CoV-2 variants of *** studies validated by reverse genetics showed that compound 172 inhibits the 3-chymotrypsin-like protease(3CLpro)by binding to an allosteric site and reduces 3CLpro dimerization.A drug synergistic checkerboard assay demonstrated that compound 172 can achieve drug synergy with nirmatrelvir in *** vivo studies confirmed the antiviral activity of compound 172 in both Golden Syrian Hamsters and K18 humanized ACE2 ***,this study identified an alternative druggable site on the SARS-CoV-23CLpro,proposed a potential combination therapy with nirmatrelvir to reduce the risk of antiviral resistance and shed light on the development of allosteric protease inhibitors for treating a range of coronavirus diseases.

关键词： SARS-CoV-2 High throughput screening Broad-spectrum antiviral treatment 3CLpro inhibitor Allosteric-site inhibitor Animal models Chemical genetics Reverse genetics

Controversies in testosterone replacement therapy： testosterone and cardiovascular disease

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Asian Journal of Andrology 2015年第2期17卷 187-191,I0006页

作者： Kathleen Hwang Martin Miner Department of Surgery (Urology) The Alpert Medical School of Brown University Providence Rhode Island USA Department of Family Medicine The Alpert Medical School of Brown University Providence Rhode Island USA.

The role of testosterone in the cardiovascular （CV） health of men is controversial. Data suggest that both the condition and treatment of clinical hypogonadism is associated with decreased CV mortality; however, two recent studies suggest that hypogonadal subjects treated with testosterone replacement therapy have a higher incidence of new CV events. There has been increased media attention concerning the risk of CV disease in men treated with testosterone. Until date, there are no long-term prospective studies to determine safety. Literature spanning over the past 30 years has suggested that not only is there a possible increased CV risk in men with low levels of testosterone, but the benefits from testosterone therapy may even lower this risk. We review here the recent studies that have garnered such intense scrutiny. This article is intended as a thorough review of testosterone levels and CV risk, providing the clinician with the facts needed to make informed clinical decisions in managing patients with clinical hypogonadism.

关键词： cardiovascular disease hypogonadism testosterone

The evolving profile and role of computer science

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science in China(Series F) 2009年第10期52卷 1778-1784页

作者： PREPARATA Franco P. Computer science Department Brown UniversityProvidence RI 02912 USA

Technological innovation ushered in the computer era, and, after a few years of tutelage by established disciplines, computer science emerged as an independent discipline. In the subsequent decades computer science developed its special identity, sharing the dual character of engineering and mathematics. This evolution is revisited here based on my personal experience. In my view, the notion of computational model has been the enabler of extraordinary creativity, and at the same time the source of critical reflection two decades ago. However, capitalizing on a vibrant technology, computer science is reinventing itself as the indispensable enabler of applications. This is a crucial profile that calls for a pedagogical adaptation, where the notion of model morphs from means to end.

关键词： computer science informatics applications modeling models of computations

Insect-specific RNA virus affects the stylet penetration activity of brown citrus aphid(Aphis citricidus)to facilitate its transmission

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Insect science 2024年第1期31卷 255-270页

作者： Xin An Qiaoying Gu Jing Wang Tengyu Chang Wei Zhang Jin-Jun Wang Jinzhi Niu Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionAcademy of Agricultural ScienceSouthwest UniversityChongqingChina

Sap-sucking insects often transmit plant viruses but also carry insect viruses,which infect insects but not *** impact of such insect viruses on insect host biology and ecology is largely ***,we identified a novel insect-specific virus carried by brown citrus aphid(Aphis citricidus),which we tentatively named Aphis citricidus picornavirus(AcPV).Phylogenetic analysis discovered a monophyletic cluster with AcPV and other unassigned viruses,suggesting that these viruses represent a new family in order *** infection with AcPV triggered aphid antiviral immunity mediated by RNA interference,resulting in asymptomatic ***,we found that AcPV was transmitted horizontally by secretion of the salivary gland into the feeding sites of *** influenced aphid stylet behavior during feeding and increased the time required for intercellular penetration,thus promoting its transmission among aphids with plants as an intermediate *** gene expression results suggested that this mechanism was linked with transcription of salivary protein genes and plant defense hormone ***,our results show that the horizontal transmission of AcPV in brown citrus aphids evolved in a manner similar to that of the circulative transmission of plant viruses by insect vectors,thus providing a new ecological perspective on the activity of insect-specific viruses found in aphids and improving the understanding of insect virus ecology.

关键词： electrical penetration graph feeding behavior insect virus transmission Picornavirales salivary protein

Mechanical Behavior Based on Aggregates Microstructure of Ultra-high Performance Concrete

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Journal of Wuhan university of Technology(Materials science) 2024年第3期39卷 673-681页

作者：丁庆军 ZHOU Changsheng 张高展 GUO Hong LI Yang ZHANG Yongyuan GUO Kaizheng School of Materials science and Engineering Wuhan University of TechnologyWuhan 430070China Advanced Building Materials Key Laboratory of Anhui Province School of Material Science and Chemical EngineeringAnhui Jianzhu UniversityHefei 230601China China Railway 17th Bureau Group Co. Ltd.Taiyuan 030006China

We developed ultra-high performance concrete(UHPC)incorporating mullite sand and brown corundum sand(BCS),and the quartz sand UHPC was utilized to prepare for *** properties of compressive strength,elastic modulus,ultrasonic pulse velocity,flexural strength,and toughness were *** electron microscopy and nanoindentation were also conducted to reveal the underlying mechanisms affecting macroscopic *** to the superior interface bonding properties between mullite sand and matrix,the compressive strength and flexural toughness of UHPC have been significantly *** sand and BCS aggregates have higher stiffness than quartz sand,contributing to the excellent elastic modulus exhibited by *** stiffness and volume of aggregates have a more significant impact on the elastic modulus of UHPC than interface performance,and the latter contributes more to the strength of *** study will provide a reference for developing UHPC with superior elastic modulus for structural engineering.

关键词： ultra-high performance concrete mechanical properties fine aggregates microstructure nanoindentation

The life-history trait trade-offs mediated by reproduction and immunity in the brown planthopper,Nilaparvata lugens Stål

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Journal of Integrative Agriculture 2024年第6期23卷 2018-2032页

作者： Dan Sun Hongfeng Wang Jiahui Zeng Qiuchen Xu Mingyun Wang Xiaoping Yu Xuping Shentu Zhejiang Provincial Key Laboratory of Biometrology and Inspection&Quarantine College of Life ScienceChina Jiliang UniversityHangzhou 310018China

Reproduction and immune defense are costly functions,and they are expected to tradeoff with each other to drive *** brown planthopper(BPH),Nilaparvata lugens Stål(Hemiptera,Delphacidae),is a global superpest that mostly damages rice ***-like symbionts(YLS)exist in the abdominal fat body tissue and are tightly associated with the development,growth,and reproduction of *** previous research demonstrated that mating behavior promotes the release of YLS from the fat body into the hemolymph in the BPH,thereby triggering an immune ***,the fitness costs related to life-history traits of BPH(such as survival rate)have a strong dependence on the relative abundance of ***,the possible relationship between reproduction and the immune response in BPH has not been *** this study,an omics-based approach was used to analyze the transcriptome of fat body tissues in mated and unmated BPH at 72 h post-eclosion,from which two antimicrobial peptide genes,NlDefensin A(NlDfA)and NlDefensin B(NlDfB),were selected since they were highly expressed in mated ***,the full-length cDNA sequences of the NlDfA and NlDfB genes were cloned and *** results showed up-regulation of the NlDfA and NlDfB genes in mated BPH when compared to unmated ***-temporal expression analysis indicated that the NlDfA and NlDfB genes were expressed in all tissues and developmental stages,and they were most highly expressed in the fat body at 24 h ***,the symbionts in BPH were significantly inhibited by the in vitro expression of the NlDfA and NlDfB ***,RNA interference(RNAi)-mediated suppression of NlDfA and NlDfB dramatically increased the relative abundance of YLS in the fat body,while YLS in the hemolymph decreased *** BPHs also displayed some fitness disadvantages in survival,fecundity,hatchability,and possibly the vertical transmission of YLS from hemolymph to *** results

关键词： Nilaparvata lugens reproduction immune defense trade-off

Periodic Variation Studies of the Two Short Period W UMa-type Eclipsing Binaries: LX Lyn and V0853 Aur

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Research in Astronomy and Astrophysics 2024年第1期24卷 273-284页

作者： Xu Zhang Bin Zhang School of Physics and Electronic science Guizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China

In this paper,new light curves(LCs) of contact eclipsing binary(CEB) systems LX Lyn and V0853 Aur are presented and analyzed by using the 2015 version of the Wilson-Devinney(W-D) *** order to explain their asymmetric LCs,cool starspots on the components were *** is suggested that their fill-out degrees are f=12.0%(LX Lyn) and f=26.3%(V0853 Aur).At the same time,we found that LX Lyn is a W-type eclipsing binary(EB) with an orbital inclination of i=84°.88 and a mass ratio of q=2.31.V0853 Aur is also a W-type CEB with a mass ratio of q=2.77 and an orbital inclination of i= 79°.*** on all available times of light minimum,their orbital period changes are studied by using the O-C *** O-C diagram of LX Lyn reveals a cyclic oscillation with a period of about 14.84 yr and an amplitude of 0.0019 days,which can be explained by the light-travel time effect(LTTE) due to the presence of a third body with a minimum mass of0.06M_⊙.For V0853 Aur,it is discovered that the O-C diagram of the system also shows a cyclic oscillation with a period of 9.64 yr and an amplitude of 0.03365 *** cyclic oscillation of V0853 Aur can be attributed to the LTTE by means of a third body with a mass no less than 3.77M_⊙.The third body may play an important role in the formation and evolution of these systems.

关键词： stars:activity (stars:)binaries(including multiple):close (stars:)binaries:eclipsing (stars:)brown dwarfs stars:evolution stars:formation

Direction finding characteristics of the bio-sonar model of a big brown bat

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Chinese Journal of Acoustics 2024年第3期43卷 380-395页

作者： WANG Feng LU Yuqing DONG Yangze College of Information science and Engineering Hohai UniversityNanjing211100 Southern Marine science and Engineering Guangdong Laboratory Zhanjiang524000

A bionic model of bat bio-sonar is established through computer simulation in this study,with a focus on investigating itsorientation measurement performance.A model for simulating bat orientation perception is created via a binaural broadband interferometer,utilizing binaural interference *** model incorporates a convolutional neural network(CNN)to achieve extraction and perception of orientation ***,the principle of multi-frequency point defuzzification is elaborated upon in the *** simulation results reveal the proposed bionic model achieves a direction measurement accuracy of 0.87◦and 0.116◦in the rough search mode and precise search mode,respectively,at a signal-to-noise ratio of 25 *** model demonstrates high accuracy in orientation recognition and defuzzification *** to the technique that employs broad phase difference to determine target orientation information,the proposed model exhibits analogous direction finding efficiency but superior defuzzification capacity.

关键词： finding utilizing precise