期刊文献+
共找到964篇文章
< 1 2 49 >
每页显示 20 50 100
Investigation on the resonance phenomena of multi-solitons for the (3+1)-dimensional Kadomtsev-Petviashvili equation 被引量:1
1
作者 石玉仁 张娟 +2 位作者 杨红娟 段文山 Karl E.Lonngren 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期473-478,共6页
In this paper, we theoretically investigate the four-soliton interaction and their resonance phenomena of the (3+1)- dimensional Kadomtsev Petviashvili (KP) equation. We find that the maximum amplitude of the res... In this paper, we theoretically investigate the four-soliton interaction and their resonance phenomena of the (3+1)- dimensional Kadomtsev Petviashvili (KP) equation. We find that the maximum amplitude of the resonantly created soliton can be 16 times that of one of the four equi-amplitude initial interacting solitons. We also find that the maximum amplitude can only be 4 times the initial soliton amplitude when the resonance phenomena does not take place. The case of four solitons with different amplitudes also has been studied analytically. The results indicate that the resonance phenomena still exists in this case. Numerical results confirm the theoretical predictions. 展开更多
关键词 Kadomtsev-Petviashvili equation SOLITON RESONANCE
下载PDF
Effects of prebiotics on the fermentation of traditional suancai of Northeast China 被引量:1
2
作者 Mingwei Zhao Xinying Cao +8 位作者 Yuzheng Wu Sibo Zou Zhigao Li Xinping Lin Chaofan Ji Liang Dong Sufang Zhang Chenxu Yu Huipeng Liang 《Food Science and Human Wellness》 SCIE CSCD 2024年第3期1358-1367,共10页
Suancai is a traditional fermented vegetable widely consumed in Northeast China.In this study,different prebiotics were used to improve the quality of suancai.Four prebiotics(inulin(INU),xylooligosaccharide(XO S),gala... Suancai is a traditional fermented vegetable widely consumed in Northeast China.In this study,different prebiotics were used to improve the quality of suancai.Four prebiotics(inulin(INU),xylooligosaccharide(XO S),galactooligosaccharide(GOS),and stachyose(STA))were shown to reduce the pH value and increase the content of total titratable acidity(TTA)in suancai,while the contents of most organic acids were also increased.The addition of prebiotics had significant effects on the bacterial microbiota during the suancai fermentation process.All prebiotics were shown to contribute to the growth of Lactobacillus.The suancai sample with fructooligosaccharides(FOS)had the highest relative abundance of Lactobacillus.Besides,INU and XOS could increase the abundance of Weissella.To evaluate the quality of suancai fermented with prebiotics,profiles of volatile flavor compounds(VOCs)and free amino acids(FAA)were analyzed.The prebiotics affected the VOCs and FAA profiles via transforming the bacterial microbiota.In addition,the addition of prebiotics also changed the taste profiles of the suancai samples.This study is among the first attempts to reveal the effects of different prebiotics on suancai fermentation,and the findings provide a foundation to develop new ways for improving the quality of suancai. 展开更多
关键词 Bacterial microbiota Lactic acid bacteria FLAVOR Amino acid TASTE
下载PDF
Speed and surface steepness affect internal tibial loading during running 被引量:1
3
作者 Hannah Rice Markus Kurz +4 位作者 Patrick Mai Leon Robertz Kevin Bill Timothy R.Derrick Steffen Willwacher 《Journal of Sport and Health Science》 SCIE CSCD 2024年第1期118-124,共7页
Background:Internal tibial loading is influenced by modifiable factors with implications for the risk of stress injury.Runners encounter varied surface steepness(gradients)when running outdoors and may adapt their spe... Background:Internal tibial loading is influenced by modifiable factors with implications for the risk of stress injury.Runners encounter varied surface steepness(gradients)when running outdoors and may adapt their speed according to the gradient.This study aimed to quantify tibial bending moments and stress at the anterior and posterior peripheries when running at different speeds on surfaces of different gradients.Methods:Twenty recreational runners ran on a treadmill at 3 different speeds(2.5 m/s,3.0 m/s,and 3.5 m/s)and gradients(level:0%;uphill:+5%,+10%,and+15%;downhill:-5%,-10%,and-15%).Force and marker data were collected synchronously throughout.Bending moments were estimated at the distal third centroid of the tibia about the medial-lateral axis by ensuring static equilibrium at each 1%of stance.Stress was derived from bending moments at the anterior and posterior peripheries by modeling the tibia as a hollow ellipse.Two-way repeated-measures analysis of variance were conducted using both functional and discrete statistical analyses.Results:There were significant main effects for running speed and gradient on peak bending moments and peak anterior and posterior stress.Higher running speeds resulted in greater tibial loading.Running uphill at+10%and+15%resulted in greater tibial loading than level running.Running downhill at-10%and-15%resulted in reduced tibial loading compared to level running.There was no difference between+5%or-5%and level running.Conclusion:Running at faster speeds and uphill on gradients≥+10%increased internal tibial loading,whereas slower running and downhill running on gradients≥-10%reduced internal loading.Adapting running speed according to the gradient could be a protective mechanism,providing runners with a strategy to minimize the risk of tibial stress injuries. 展开更多
关键词 Bending moments GRADIENT Musculoskeletal modeling Overuse injury Tibial stress Training factors
下载PDF
Prevalence and ecological factors affecting the distribution of plant-parasitic nematodes in Prunus groves in Spain
4
作者 Ilenia Clavero-Camacho Antonio Archidona-Yuste +2 位作者 Carolina Cantalapiedra-Navarrete Pablo Castillo Juan Emilio Palomares-Rius 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第2期566-589,共24页
A wide survey was conducted to study plant-parasitic nematodes(PPNs)associated with Prunus groves in Spain.This research aimed to determine the prevalence and distribution of PPNs in Prunus groves,as well as the influ... A wide survey was conducted to study plant-parasitic nematodes(PPNs)associated with Prunus groves in Spain.This research aimed to determine the prevalence and distribution of PPNs in Prunus groves,as well as the influence of explanatory variables describing soil,climate and agricultural management in structuring the variation of PPNs community composition.A total of 218 sampling sites were surveyed and 84 PPN species belonging to 32 genera were identified based of an integrative taxonomic approach.PPN species considered as potential limiting factors in Prunus production,such as Meloidogyne arenaria,M.incognita,M.javanica,Pratylenchus penetrans and P.vulnus,were identified in this survey.Seven soil physico-chemical(C,Mg,N,Na,OM,P,pH and clay,loamy sand and sandy loam texture classes),four climate(Bio04,Bio05,Bio13 and Bio14)and four agricultural management variables(grove-use history less than 10 years,irrigation,apricot seedling rootstock,and Montclar rootstock)were identified as the most influential variables driving spatial patterns of PPNs communities.In particular,younger plantations showed higher values for species richness and diversity indices than groves cultivated for more than 20 years with Prunus spp.Our study increases the knowledge of the distribution and prevalence of PPNs associated with Prunus rhizosphere,as well as on the influence of explanatory variables driving the spatial structure PPNs communities,which has important implications for the successful design of sustainable management strategies in the future in this agricultural system. 展开更多
关键词 nematodes MELOIDOGYNE PRATYLENCHUS Paratylenchus ROOTSTOCK DISTRIBUTION soil grove-use ALMOND peach
下载PDF
Continual Reinforcement Learning for Intelligent Agricultural Management under Climate Changes
5
作者 Zhaoan Wang Kishlay Jha Shaoping Xiao 《Computers, Materials & Continua》 SCIE EI 2024年第10期1319-1336,共18页
Climate change poses significant challenges to agricultural management,particularly in adapting to extreme weather conditions that impact agricultural production.Existing works with traditional Reinforcement Learning(... Climate change poses significant challenges to agricultural management,particularly in adapting to extreme weather conditions that impact agricultural production.Existing works with traditional Reinforcement Learning(RL)methods often falter under such extreme conditions.To address this challenge,our study introduces a novel approach by integrating Continual Learning(CL)with RL to form Continual Reinforcement Learning(CRL),enhancing the adaptability of agricultural management strategies.Leveraging the Gym-DSSAT simulation environment,our research enables RL agents to learn optimal fertilization strategies based on variable weather conditions.By incorporating CL algorithms,such as Elastic Weight Consolidation(EWC),with established RL techniques like Deep Q-Networks(DQN),we developed a framework in which agents can learn and retain knowledge across diverse weather scenarios.The CRL approach was tested under climate variability to assess the robustness and adaptability of the induced policies,particularly under extreme weather events like severe droughts.Our results showed that continually learned policies exhibited superior adaptability and performance compared to optimal policies learned through the conventional RL methods,especially in challenging conditions of reduced rainfall and increased temperatures.This pioneering work,which combines CL with RL to generate adaptive policies for agricultural management,is expected to make significant advancements in precision agriculture in the era of climate change. 展开更多
关键词 Continual learning reinforcement learning agricultural management climate variability
下载PDF
Anderson Acceleration of Gradient Methods with Energy for Optimization Problems
6
作者 Hailiang Liu Jia-Hao He Xuping Tian 《Communications on Applied Mathematics and Computation》 EI 2024年第2期1299-1318,共20页
Anderson acceleration(AA)is an extrapolation technique designed to speed up fixed-point iterations.For optimization problems,we propose a novel algorithm by combining the AA with the energy adaptive gradient method(AE... Anderson acceleration(AA)is an extrapolation technique designed to speed up fixed-point iterations.For optimization problems,we propose a novel algorithm by combining the AA with the energy adaptive gradient method(AEGD)[arXiv:2010.05109].The feasibility of our algorithm is ensured in light of the convergence theory for AEGD,though it is not a fixed-point iteration.We provide rigorous convergence rates of AA for gradient descent(GD)by an acceleration factor of the gain at each implementation of AA-GD.Our experimental results show that the proposed AA-AEGD algorithm requires little tuning of hyperparameters and exhibits superior fast convergence. 展开更多
关键词 Anderson acceleration(AA) Gradient descent(GD) Energy stability
下载PDF
基于注意力机制与自适应特征融合的群养猪身份识别
7
作者 韩丁磊 陈晨 +5 位作者 Steibel Juan Siegford Janice 韩俊杰 王梦凡 徐雷钧 Norton Tomas 《软件导刊》 2024年第6期25-31,共7页
针对群养猪攻击过程中身体形变和重叠影响猪身份识别精度的问题,开发一种基于注意力机制和自适应特征融合的深度学习方法以提高猪身份识别精度。录制猪栏中8只猪每天8小时共3天的视频,并筛选含攻击的16830帧作为数据集。首先,采用ResNe... 针对群养猪攻击过程中身体形变和重叠影响猪身份识别精度的问题,开发一种基于注意力机制和自适应特征融合的深度学习方法以提高猪身份识别精度。录制猪栏中8只猪每天8小时共3天的视频,并筛选含攻击的16830帧作为数据集。首先,采用ResNet50提取猪的卷积神经网络(CNN)特征;然后,采用特征金字塔网络(FPN)在ResNet50中选择3层不同尺度的特征,以优化这些特征的定位和语义信息;接着,采用自注意力机制提高这些特征的区分度,并采用自适应空间特征融合(ASFF)以融合不同尺度的特征;最后,利用卷积和Sigmoid函数相结合的检测器对猪身份进行识别。使用该方法后,猪身份识别的均值平均精度(mAP)达到95.59%,速度达到37.6 f/s。结果表明,该方法能够在攻击场景下有效识别猪身份,有助于将攻击识别从群体级细化为个体级。 展开更多
关键词 群养猪 身份识别 注意力机制 特征融合 深度学习
下载PDF
非洲在动荡与变革中奋力前行
8
作者 黎文涛 殷悦 孙红 《Contemporary International Relations》 2024年第1期102-108,共7页
In 2023, the overall situation in Africa remained relatively stable. However, a resurgence of coups d'état has affected the region from political and security points of view. The world's major powers are ... In 2023, the overall situation in Africa remained relatively stable. However, a resurgence of coups d'état has affected the region from political and security points of view. The world's major powers are stepping up their contest in Africa, reshuffling the geopolitical landscape. In the face of interwoven turbulence and change, African countries have increased their efforts to build a stronger continent through unity and to speak with one voice internationally. 展开更多
关键词 SPEAK TURBULENCE AFRICA
下载PDF
Orientation and Decision-Making for Soccer Based on Sports Analytics and AI:A Systematic Review
9
作者 Zhiqiang Pu Yi Pan +4 位作者 Shijie Wang Boyin Liu Min Chen Hao Ma Yixiong Cui 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第1期37-57,共21页
Due to ever-growing soccer data collection approaches and progressing artificial intelligence(AI) methods, soccer analysis, evaluation, and decision-making have received increasing interest from not only the professio... Due to ever-growing soccer data collection approaches and progressing artificial intelligence(AI) methods, soccer analysis, evaluation, and decision-making have received increasing interest from not only the professional sports analytics realm but also the academic AI research community. AI brings gamechanging approaches for soccer analytics where soccer has been a typical benchmark for AI research. The combination has been an emerging topic. In this paper, soccer match analytics are taken as a complete observation-orientation-decision-action(OODA) loop.In addition, as in AI frameworks such as that for reinforcement learning, interacting with a virtual environment enables an evolving model. Therefore, both soccer analytics in the real world and virtual domains are discussed. With the intersection of the OODA loop and the real-virtual domains, available soccer data, including event and tracking data, and diverse orientation and decisionmaking models for both real-world and virtual soccer matches are comprehensively reviewed. Finally, some promising directions in this interdisciplinary area are pointed out. It is claimed that paradigms for both professional sports analytics and AI research could be combined. Moreover, it is quite promising to bridge the gap between the real and virtual domains for soccer match analysis and decision-making. 展开更多
关键词 Artificial intelligence(AI) DECISION-MAKING FOOTBALL review SOCCER sports analytics
下载PDF
Population genomic analysis reveals key genetic variations and the driving force for embryonic callus induction capability in maize
10
作者 Peng Liu Langlang Ma +8 位作者 Siyi Jian Yao He Guangsheng Yuan Fei Ge Zhong Chen Chaoying Zou Guangtang Pan Thomas Lübberstedt Yaou Shen 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第7期2178-2195,共18页
Genetic transformation has been an effective technology for improving the agronomic traits of maize.However,it is highly reliant on the use of embryonic callus(EC)and shows a serious genotype dependence.In this study,... Genetic transformation has been an effective technology for improving the agronomic traits of maize.However,it is highly reliant on the use of embryonic callus(EC)and shows a serious genotype dependence.In this study,we performed genomic sequencing for 80 core maize germplasms and constructed a high-density genomic variation map using our newly developed pipeline(MQ2Gpipe).Based on the induction rate of EC(REC),these inbred lines were categorized into three subpopulations.The low-REC germplasms displayed more abundant genetic diversity than the high-REC germplasms.By integrating a genome-wide selective signature screen and region-based association analysis,we revealed 95.23 Mb of selective regions and 43 REC-associated variants.These variants had phenotypic variance explained values ranging between 21.46 and 49.46%.In total,103 candidate genes were identified within the linkage disequilibrium regions of these REC-associated loci.These genes mainly participate in regulation of the cell cycle,regulation of cytokinesis,and other functions,among which MYB15 and EMB2745 were located within the previously reported QTL for EC induction.Numerous leaf area-associated variants with large effects were closely linked to several REC-related loci,implying a potential synergistic selection of REC and leaf size during modern maize breeding. 展开更多
关键词 MAIZE genetic transformation embryonic callus selective signal association analysis
下载PDF
Digesting gluten with oral endopeptidases to improve the management of celiac disease
11
作者 Katelin Durham Mirac Nedim Ince 《World Journal of Gastroenterology》 SCIE CAS 2024年第26期3201-3205,共5页
In our editorial,we want to comment on the article by Stefanolo et al titled“Effect of Aspergillus niger prolyl endopeptidase in patients with celiac disease on a long-term gluten-free diet”.Celiac disease is an imm... In our editorial,we want to comment on the article by Stefanolo et al titled“Effect of Aspergillus niger prolyl endopeptidase in patients with celiac disease on a long-term gluten-free diet”.Celiac disease is an immune-mediated disorder triggered by dietary gluten in genetically predisposed individuals.Although avoiding gluten can permit patients to live symptom-free,ongoing voluntary or involuntary exposure to gluten is common and associated with persistent villous atrophy in small bowel mucosa.As villous atrophy predisposes patients to life threatening complications,such as osteoporotic fractures or malignancies,therapeutic adjuncts to gluten-free diet become important to improve patients’quality of life and,if these adjuncts can be shown to improve villous atrophy,avoid complications.Oral administration of enzyme preparations,such as endopeptidases that digest gluten and mitigate its antigenicity to trigger inflam-mation,is one clinical strategy under investigation.The article is about the utility of one endopeptidase isolated from Aspergillus niger.We critique findings of this clinical trial and also summarize endopeptidase-based as well as other strategies and how they can complement gluten-free diet in the management of celiac disease. 展开更多
关键词 Celiac disease Gluten-free diet ENDOPEPTIDASE Villous atrophy Aspergillus niger Adjunct therapy
下载PDF
Efficiency of Botanical and Chemical Pesticides on the Control of Field Insect Pests under Cowpea Production
12
作者 John Ssengo Brian Zebosi Jeninah Karungi 《American Journal of Plant Sciences》 CAS 2024年第3期203-221,共19页
The pulse cowpea [Vigna unguiculata (L.) Walp] holds a significant agricultural position in Uganda, ranking fourth among legume crops, following common beans, groundnuts, and soybeans. Known for its versatility, cowpe... The pulse cowpea [Vigna unguiculata (L.) Walp] holds a significant agricultural position in Uganda, ranking fourth among legume crops, following common beans, groundnuts, and soybeans. Known for its versatility, cowpeas are consumable at various developmental stages, from early seedling to maturity. However, the crop faces persistent pest challenges at each stage, leading to substantial yield losses. In Uganda, chemical insecticides are the primary pest control means, but their increased and excessive use raises environmental, health, and economic concerns. This has prompted a quest for alternative and sustainable solutions, prompting an exploration of botanical insecticides. This study, conducted at Makerere University Agricultural Research Institute (MUARIK), aimed to evaluate the effectiveness of three selected botanical insecticides versus four established chemical insecticides for managing cowpea insect pests under field conditions. The treatments included: Carbofuran, Cypermethrin 10% EC, Dimethoate, Pestwin, Pyrethrum ewc , Pyrethrum 5ew, Profenofos 40% Cypermethrin 4% EC mix, and Untreated, arranged in a randomized complete block design with three replications. The significant pests studied were aphids, thrips, pod-sucking bugs, and legume pod borer. Results indicated substantial impacts of the treatments on pest infestation, with Profenofos 40% Cypermethrin 4% EC being the most effective against most pests. The plant parameter, plant height, was significantly affected by treatments in 2016B, while the number of pods was impacted in 2017A. Pestwin, a botanical insecticide blend (containing Azadirachtin indica, Pongamia pinnata, and Ricinus communis extracts) demonstrated superior efficacy against cowpea aphids. Moreover, it positively influenced plant height, number of pods, and pod biomass, surpassing many chemical insecticides. Pestwin’s environmental friendliness positions it as a potential contributor to reducing environmental pollution, making it a promising candidate for inclusion in IPM programs. Overall, the study underscores the importance of exploring botanical alternatives to chemical insecticides for sustainable pest management in cowpea cultivation. 展开更多
关键词 COWPEA Pest Management Botanical Solutions PROFENOFOS SUSTAINABILITY
下载PDF
Measurement,associations,patterns,and promotion:Unveiling vital areas in physical activity epidemiology
13
作者 Kara M.Whitaker Guest editor Michael J.LaMonte 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第5期605-607,共3页
Physical activity(PA)epidemiology first emerged as a new field of study around the 1950s with publication of seminal investigations on London civil servants1 and has continued to evolve as a scientific discipline to p... Physical activity(PA)epidemiology first emerged as a new field of study around the 1950s with publication of seminal investigations on London civil servants1 and has continued to evolve as a scientific discipline to present time.This subdiscipline of epidemiology studies the frequencies,distributions,and dynamics of PA and its impact on human health,morbidity,and mortality.Research over the past 75 years has demonstrated numerous health benefits of PA.Based on these research findings,the World Health Organization recommends adults aged 18-64 years engage in at least 150-300 min of moderate-intensity aerobic PA per week,or at least 75-150 min of vigorous-intensity aerobic PA per week,or a combination of both intensities. 展开更多
关键词 EPIDEMIOLOGY PROMOTION continued
下载PDF
Exploring the genetic control of sweat gland characteristics in beef cattle for enhanced heat tolerance
14
作者 Aakilah S.Hernandez Gabriel A.Zayas +5 位作者 Eduardo E.Rodriguez Kaitlyn M.Sarlo Davila Fahad Rafiq Andrea N.Nunez Cristiane Goncalves Titto Raluca G.Mateescu 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第5期1820-1831,共12页
Background Thermal stress in subtropical regions is a major limiting factor in beef cattle production systems with around$369 million being lost annually due to reduced performance.Heat stress causes numerous physiolo... Background Thermal stress in subtropical regions is a major limiting factor in beef cattle production systems with around$369 million being lost annually due to reduced performance.Heat stress causes numerous physiological and behavioral disturbances including reduced feed intake and decreased production levels.Cattle utilize various physiological mechanisms such as sweating to regulate internal heat.Variation in these traits can help identify genetic variants that control sweat gland properties and subsequently allow for genetic selection of cattle with greater thermotolerance.Methods This study used 2,401 Brangus cattle from two commercial ranches in Florida.Precise phenotypes that contribute to an animal's ability to manage heat stress were calculated from skin biopsies and included sweat gland area,sweat gland depth,and sweat gland length.All animals were genotyped with the Bovine GGP F250K,and BLUPF90 software was used to estimate genetic parameters and for Genome Wide Association Study.Results Sweat gland phenotypes heritability ranged from 0.17 to 0.42 indicating a moderate amount of the phenotypic variation is due to genetics,allowing producers the ability to select for favorable sweat gland properties.A weighted single-step GWAS using sliding 10 kb windows identified multiple quantitative trait loci(QTLs)explaining a significant amount of genetic variation.QTLs located on BTA7 and BTA12 explained over 1.0%of genetic variance and overlap the ADGRV1 and CCDC168 genes,respectively.The variants identified in this study are implicated in processes related to immune function and cellular proliferation which could be relevant to heat management.Breed of Origin Alleles(BOA)were predicted using local ancestry in admixed populations(LAMP-LD),allowing for identification of markers'origin from either Brahman or Angus ancestry.A BOA GWAS was performed to identify regions inherited from particular ancestral breeds that might have a significant impact on sweat gland phenotypes.Conclusions The results of the BOA GWAS indicate that both Brahman and Angus alleles contribute positively to sweat gland traits,as evidenced by favorable marker effects observed from both genetic backgrounds.Understanding and utilizing genetic traits that confer better heat tolerance is a proactive approach to managing the impacts of climate change on livestock farming. 展开更多
关键词 GWAS HERITABILITY SKIN THERMOTOLERANCE
下载PDF
HI in High Gas-phase Metallicity Dwarf Galaxy WISEA J230615.06+143927.9
15
作者 Yan Guo C.Sengupta +2 位作者 T.C.Scott P.Lagos Y.Luo 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期292-299,共8页
We present resolved Giant Metrewave Radio Telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a Tidal Dwa... We present resolved Giant Metrewave Radio Telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a Tidal Dwarf Galaxy(TDG) candidate. TDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g-r color of 0.23 mag, irregular optical morphology and high-metallicity(12 +log(O/H) = 8.68 ± 0.14), making it an interesting galaxy to study in more detail. We find J2306 to be an H I rich galaxy with a large extended, unperturbed rotating H I disk. Using our H I data we estimated its dynamical mass and found the galaxy to be dark matter(DM) dominated within its H I radius. The quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved TDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the H I morphology and kinematics of the galaxy show no indication of a recent merger to explain the high-metallicity.Further detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment. 展开更多
关键词 galaxies:abundances galaxies:dwarf galaxies:irregular radio lines:galaxies radio lines:ISM
下载PDF
Superconvergence of Direct Discontinuous Galerkin Methods:Eigen-structure Analysis Based on Fourier Approach
16
作者 Xuechun Liu Haijin Wang +1 位作者 Jue Yan Xinghui Zhong 《Communications on Applied Mathematics and Computation》 EI 2024年第1期257-278,共22页
This paper investigates superconvergence properties of the direct discontinuous Galerkin(DDG)method with interface corrections and the symmetric DDG method for diffusion equations.We apply the Fourier analysis techniq... This paper investigates superconvergence properties of the direct discontinuous Galerkin(DDG)method with interface corrections and the symmetric DDG method for diffusion equations.We apply the Fourier analysis technique to symbolically compute eigenvalues and eigenvectors of the amplification matrices for both DDG methods with different coefficient settings in the numerical fluxes.Based on the eigen-structure analysis,we carry out error estimates of the DDG solutions,which can be decomposed into three parts:(i)dissipation errors of the physically relevant eigenvalue,which grow linearly with the time and are of order 2k for P^(k)(k=2,3)approximations;(ii)projection error from a special projection of the exact solution,which is decreasing over the time and is related to the eigenvector corresponding to the physically relevant eigenvalue;(iii)dissipative errors of non-physically relevant eigenvalues,which decay exponentially with respect to the spatial mesh sizeΔx.We observe that the errors are sensitive to the choice of the numerical flux coefficient for even degree P^(2)approximations,but are not for odd degree P^(3)approximations.Numerical experiments are provided to verify the theoretical results. 展开更多
关键词 Direct discontinuous Galerkin(DDG)method with interface correction Symmetric DDG method SUPERCONVERGENCE Fourier analysis Eigen-structure
下载PDF
中法早期文化交流:“国王数学家”描述的北京城
17
作者 白志敏 《国际比较文学(中英文)》 2024年第2期41-57,共17页
1685年法国国王路易十四派遣了第一批“国王数学家”前往中国,李明(Louis Lecomte)是五位到达北京的法国耶稣会士之一,并在1688年到达后受到康熙皇帝召见,中法两国间从此开启了近百年的早期文化交流。李明是十七世纪末最早深入中国各地... 1685年法国国王路易十四派遣了第一批“国王数学家”前往中国,李明(Louis Lecomte)是五位到达北京的法国耶稣会士之一,并在1688年到达后受到康熙皇帝召见,中法两国间从此开启了近百年的早期文化交流。李明是十七世纪末最早深入中国各地考察、游历、传教,并对他所见所闻进行详尽分析描述的法国人。综观他笔下北京城的描述,我们不难发现,作者始终抱着强烈的好奇心,以亲眼探索北京城的姿态审视异国都城里能够看到的一切,他的描写宛若一幅康熙年间北京城写实的画面。李明对北京古老的历史,独特的建筑风格,以及繁荣的商业氛围等都做了比较客观的描述,这为“启蒙时代”的法国读者传递了比较翔实的信息。由于“礼仪之争”的原因,他只好奉命回到法国解释有关中国传教的情况,1696年他在巴黎出版了在中国期间给法国上层人士的十四封书信,取名为《中国近况新志》(Nouveaux mémoiressurl’étatprésentde la Chine)。尽管李明在中国停留的时间很短暂,但是回到法国后出版的十四封长信已经对中国社会进行了颇为详细的介绍,而且他分析的内容不但全面详细,而且不少内容是对当时中国和法国的情况进行的文化和历史的对比。本文着重研究李明关于北京城特点的分析和描述,特别是他对中、法城市区别的对比。李明对北京城的观察和分析为当今学者的北京历史研究提供了第一手真实的史料。 展开更多
关键词 国王数学家 康熙皇帝 耶稣会士 北京城 启蒙时代 《中国近况新志》
下载PDF
Fat or fillers:The dilemma in eyelid surgery 被引量:1
18
作者 Giovanni Miotti Luca De Marco +8 位作者 Davide Quaglia Martina Grando Carlo Salati Leopoldo Spadea Caterina Gagliano Mutali Musa Pier Luigi Surico Pier Camillo Parodi Marco Zeppieri 《World Journal of Clinical Cases》 SCIE 2024年第17期2951-2965,共15页
The aging of the periocular region has always aroused great interest.A fresh,young,and attractive sight determined an ever-greater attention to surgical and non-surgical techniques to obtain this result.In particular,... The aging of the periocular region has always aroused great interest.A fresh,young,and attractive sight determined an ever-greater attention to surgical and non-surgical techniques to obtain this result.In particular,the change in the concept of a young look,considered then“full”,led to the increasing use of surgical(fat grafting)or medical(hyaluronic acid)filling techniques.Eyelid rejuvenation became increasingly popular in the field of cosmetic treatments,with a focus on achieving a youthful and refreshed appearance.Among the various techniques available,the choice between using fat grafting or fillers presented a clinical dilemma.In particular,what surgery considered of fundamental importance was a long-lasting result over time.On the other hand,aesthetic medicine considered it fundamental not to have to resort to invasive treatments.But what was the reality?Was there one path better than the other,and above all,was there a better path for patients?The minireview aims to explore the physiopathology,diagnosis,treatment options,prognosis,and future studies regarding this dilemma.We analyzed the literature produced in the last 20 years comparing the two techniques.Current literature reveals advancements in biomaterials,stem cell research and tissue engineering held promise for further enhancing the field of eyelid rejuvenation.The choice between fat grafting and fillers in eyelid cosmetic treatments presented a clinical dilemma.Understanding physiopathology,accurately diagnosing eyelid aging,exploring treatment options,assessing prognosis,and conducting future studies were essential for providing optimal care to patients seeking eyelid rejuvenation. 展开更多
关键词 Stem cells Adipose stem cell Ocular therapy Oculoplastics REGENERATIVE
下载PDF
Investigation of Projectile Impact Behaviors of Graphene Aerogel Using Molecular Dynamics Simulations
19
作者 Xinyu Zhang Wenjie Xia +2 位作者 Yang Wang Liang Wang Xiaofeng Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第6期3047-3061,共15页
Graphene aerogel(GA),as a novel solid material,has shown great potential in engineering applications due to its unique mechanical properties.In this study,the mechanical performance of GA under high-velocity projectil... Graphene aerogel(GA),as a novel solid material,has shown great potential in engineering applications due to its unique mechanical properties.In this study,the mechanical performance of GA under high-velocity projectile impacts is thoroughly investigated using full-atomic molecular dynamics(MD)simulations.The study results show that the porous structure and density are key factors determining the mechanical response of GA under impact loading.Specifically,the impact-induced penetration of the projectile leads to the collapse of the pore structure,causing stretching and subsequent rupture of covalent bonds in graphene sheets.Moreover,the effects of temperature on the mechanical performance of GA have been proven to be minimal,thereby highlighting the mechanical stability of GA over a wide range of temperatures.Finally,the energy absorption density(EAD)and energy absorption efficiency(EAE)metrics are adopted to assess the energy absorption capacity of GA during projectile penetration.The research findings of this work demonstrate the significant potential of GA for energy absorption applications. 展开更多
关键词 Graphene aerogel molecular dynamics simulation impact response energy absorption
下载PDF
Exploring Nutritional Compositions,Volatile Compounds,Health Benefits,Emerging Processing Technologies,and Potential Food Products of Glutinous Rice:A Review
20
作者 Maimunah Mohd ALI Norhashila HASHIM 《Rice science》 SCIE CSCD 2024年第3期251-268,共18页
Glutinous rice(Oryza sativa var.glutinosa)stands out as one of the most popular rice varieties globally,amidst thousands of rice cultivars.Its increasing popularity is attributed to its rich nutritional compositions a... Glutinous rice(Oryza sativa var.glutinosa)stands out as one of the most popular rice varieties globally,amidst thousands of rice cultivars.Its increasing popularity is attributed to its rich nutritional compositions and health benefits.This review aims to summarize the nutritional compositions,volatile compounds,and health benefits of glutinous rice.Further,in-depth studies are necessary to explore the utilization of glutinous rice in enhancing processing technologies and developing new food products.Glutinous rice has been shown to possess numerous health benefits,including antioxidant activity,bioactive compounds,anti-cancer properties,anti-inflammatory effects,anti-diabetic potential,and cholesterol-lowering effects.Besides its nutritional compositions,the major volatile compounds identified in glutinous rice could serve as a functional food for human consumption.Emerging processing technologies related to glutinous rice are elaborated to improve the latest developments for incorporating them into various food products. 展开更多
关键词 glutinous rice health benefit volatile compound nutritional composition processing technology
下载PDF
上一页 1 2 49 下一页 到第
使用帮助 返回顶部