An Improved Extreme Learning Machine Prediction Model for Ionospheric Total Electron Content

Earth’s ionosphere is an important medium for navigation,communication,and radio wave transmission.Total Electron Content(TEC)is a descriptive quantify for ionospheric research.However,the traditional empirical model could not fully consider the changes of TEC time series,the prediction accuracy level of TEC data performed not high.In this study,an improved Extreme Learning Machine(ELM)model is proposed for ionospheric TEC prediction.Improvements involved the use of Empirical Mode Decomposition(EMD)and a Fuzzy C-Means(FCM)clustering algorithm to pre-process data used as input to the ELM model.The proposed model fully uses the TEC data characteristics and expected to perform better prediction accuracy.TEC measurements provided by the Centre for Orbit Determination in Europe(CODE)were used to evaluate the performance of the improved ELM model in terms of prediction accuracy,applicable latitude,and the number of required training samples.Experimental results produced a Mean Relative Error(MRE)and a Root Mean Square Error(RMSE)of 8.5%and 1.39 TECU,respectively,outperforming the ELM algorithm(RMSE=2.33 TECU and MRE=17.1%).The improved ELM model exhibited particularly high prediction accuracy in mid-latitude regions,with a mean relative error of 7.6%.This value improved further as the number of available training data increased and when 20-doys data were trained,achieving a mean relative error of 4.9%.These results suggest the proposed model offers higher prediction accuracy than conventional algorithms.

Thermometry utilizing stored short-wavelength spin waves in cold atomic ensembles

Temperature,as a measure of thermal motion,is a significant parameter characterizing a cold atomic ensemble optical quantum memory.In a cold gas,storage lifetime strongly depends on its temperature and is associated with the spin wave decoherence.Here we experimentally demonstrate a new spin wave thermometry method relying on this direct dependence.The short-wavelength spin waves resulting from the counter-propagating configuration of the control and the probe laser beams make this thermometry highly suitable for probing in situ the atomic motion in elongated clouds as the ones used in quantum memories.Our technique is realized with comparable precision for memories that rely on electromagnetically induced transparency as well as far-detuned Raman storage.

Bond Performance of Adhesively Bonding Interface of Steel-Bamboo Composite Structure

The steel-bamboo composite structure is a newly developed structure,combining phyllostachys pubescens(also called Moso bamboo)plywood and cold-formed thin-walled steel with structural adhesive.The reliability of steelbamboo interface is the premise of composite effect.13 specimens were prepared to investigate the failure modes and mechanism of the steel-bamboo interface on the basis of push-out test,and the strain difference analysis method was proposed to study the distribution of shear stress.The results show that the main failure modes of steel-bamboo interface are adhesion failure and splitting of bamboo plywood.The shear stress is not evenly distributed along the longitudinal direction of the interface,showing a shape of“larger at two ends and smaller in the middle”.The lower end of the interface is the initial location of the interface failure and the shear stress concentration degree is positively correlated with the thickness of the externally bonded bamboo plate.The shear resistance of steel-bamboo interface can be enhanced by improving the adhesion between steel and structural adhesive and ameliorating the quality of bamboo products.

大型变压器螺旋式绕组扭转变形的仿真研究

变压器发生短路时,螺旋式绕组所受的短路电动力将包含很大的切向力.轴向电流分量与辐向漏磁场共同作用会产生较大的扭矩.文章中建立了螺旋式绕组的二维和三维磁场-结构力场耦合模型,对变压器的漏磁场、螺旋式绕组的切向力进行了仿真计算.得到了变压器短路时低压螺旋式绕组的切向力大小、分布规律.通过两种建模结果的对比分析,检验了计算方法的可靠性.在此基础上,研究了螺旋角和轴向预压紧力对螺旋式绕组切向位移的影响,得到了产品设计中减小绕组切向位移的-些应用结论.

Probability estimation based on grey system theory for simulation evaluation

In the evaluation of some simulation systems, only small samples data are gotten due to the limited conditions. In allusion to the evaluation problem of small sample data, an interval estimation approach with the improved grey confidence degree is proposed.On the basis of the definition of grey distance, three kinds of definition of the grey weight for every sample element in grey estimated value are put forward, and then the improved grey confidence degree is designed. In accordance with the new concept, the grey interval estimation for small sample data is deduced. Furthermore,the bootstrap method is applied for more accurate grey confidence interval. Through resampling of the bootstrap, numerous small samples with the corresponding confidence intervals can be obtained. Then the final confidence interval is calculated from the union of these grey confidence intervals. In the end, the simulation system evaluation using the proposed method is conducted. The simulation results show that the reasonable confidence interval is acquired, which demonstrates the feasibility and effectiveness of the proposed method.

Photosynthetic traits and antioxidative defense responses of Pinus yunnanensis after joint attack by bark beetles Tomicus yunnanensis and T.minor

Bark beetles Tomicus yunnanensis and T.minor are two important pests of Pinus yunnanensis and can cause massive death of pine trees.In this study,we examined several traits related to photosynthesis in P.yunnanensis and their relationship with antibiotic defense responses after joint attack by the two bark beetles at the shoot and the trunk stages.When shoots were attacked by the beetles,the abundance of chlorophylls,carotenoids,and the rates of net photosynthesis(Pn)and transpiration(E)decreased in needles,while the levels of superoxide dismutase and malondialdehyde remained unchanged in both needles and phloem.The activity of peroxidases also remained unchanged in needles,but increased in phloem.The activity of catalases increased in both needles and phloem.When trunks were attacked by the bark beetles,chlorophyll abundance,Pn,E,and antioxidative enzyme activities all declined,and the declines were more pronounced than in the attacked shoots.A decrease in protein concentrations was also observed in needles and phloem from the attacked pines.Attack on shoots by the bark beetles suppressed host defense and provided a favorable environment for larval growth and development,resulting in long-term decline of pine growth potential.The results suggest that attacks on trunks by beetles caused more severe damage to host trees than attacks on shoots.

Estimating the Empirical Null Distribution of Maxmean Statistics in Gene Set Analysis

Gene Set Analysis (GSA) is a framework for testing the association of a set of genes and the outcome, e.g. disease status or treatment group. The method replies on computing a maxmean statistic and estimating the null distribution of the maxmean statistics via a restandardization procedure. In practice, the pre-determined gene sets have stronger intra-correlation than genes across sets. This may result in biases in the estimated null distribution. We derive an asymptotic null distribution of the maxmean statistics based on sparsity assumption. We propose a flexible two group mixture model for the maxmean statistics. The mixture model allows us to estimate the null parameters empirically via maximum likelihood approach. Our empirical method is compared with the restandardization procedure of GSA in simulations. We show that our method is more accurate in null density estimation when the genes are strongly correlated within gene sets.

一种智能变电站过程层链路中断诊断方法

智能变电站引入过程层的概念,过程层网络包括SV网和GOOSE网,负责全站数据采集和开关控制,其可靠性和实时性要求很高.链路中断是光纤回路中常见故障.为了保证电网安全可靠性运行,快速确定链路中断的具体位置并及时处理是非常必要的.本文提出了种基于逻辑连接图的过程层链路中断诊断方法.

Function-oriented design:A novel strategy for advanced biomedical materials

It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.

Big stride in gene therapy for hemophilia B in China

In a recent issue of Lancet Haematology,Xue et al1 reported an adeno-associated virus(AAV)-based gene therapy in 10 patients with hemophilia B(HB)from China.BBM-H901,a novel vector comprised of an engineered liver-tropic AAV capsid(AAV843),synthesized liver-specific promoter and CpG reduced factor IX(FIX)Padua coding sequence,was infused in 10 patients(baseline FIX coagulation activity[FIX:C]were less than 2 IU/dL)after 1 week of prophylactic prednisone pretreatment(1 mg/kg per day).After a median follow-up of 58 weeks,mean FIX:C reached 36.9±20·5 IU/dL.No FIX inhibitors or serious adverse events were observed.All patients developed high titer neutralizing antibodies against vector capsid.The concentrations of alanine aminotransferase and aspartate aminotransferase in plasma were below the upper limit of normal range in 8 patients.No FIX concentrate infusion was needed after gene therapy for these patients.This is a huge step forward in the treatment of HB in China.

传粉昆虫下降背景下的授粉生态弹性:内涵、机制和展望

全球传粉昆虫多样性正在下降,如何保障农林生态系统传粉功能是当前研究的热点。理论上说,传粉功能不仅与生态系统的传粉昆虫多样性相关,还与生态系统的调节能力有关。近年来,学者们逐渐认识到授粉生态弹性对传粉功能的影响。本文在回顾已有研究的基础之上,总结传粉昆虫授粉生态弹性的内涵,厘清授粉生态弹性与工程弹性、稳定性和抗性的异同。目前,学者对授粉生态弹性形成机制开展广泛探讨,提出功能冗余假说、密度补偿假说、响应多样性假说、连接周转假说和跨尺度弹性假说,但这5个假说间的关系仍不清楚,存在一词多义、词意混淆等现象。我们依次阐述功能冗余假说、密度补偿假说、响应多样性假说、连接周转假说和跨尺度弹性假说,介绍不同假说中授粉生态弹性形成过程、研究热点和发展动态。通过解析授粉生态弹性的形成机制可知,5个假说在内涵上存在紧密联系,它们从不同空间尺度和研究对象下解释传粉昆虫授粉生态弹性的形成机制。未来授粉生态弹性研究将整合传粉昆虫群落动态和传粉功能动态的量化方法,通过实验验证5个假说的合理性,并揭示不同假说间的联系,由此阐明授粉生态弹性的发生条件、形成阈值和动态规律。随着研究的深入,授粉生态弹性理论有望用于指导农林生态系统传粉功能的经营管理。

Apache IoTDB的分布式框架设计

Apache IoTDB是一个新型的开源时序数据库管理系统.分布式数据管理系统不仅需要解决数据分区与多副本带来的节点间元数据同步问题,还要支持高效查询请求处理.本文针对节点间元数据同步问题提出了双层粒度元数据管理策略,在此基础上基于一致性哈希分区方法和Raft协议设计了同时支持强一致性查询和最终一致性查询的分布式框架.基于单机版Apache IoTDB进行了系统实现与实验测试,测试结果表明:双层粒度元数据管理策略与单层粒度管理策略相比,其元数据内存资源占用更少且写入性能提升5%~10%,并且分布式Apache IoTDB的读写性能随着集群规模的扩大而线性增长.

OsGRF4 controls grain shape, panicle length and seed shattering in rice

Traits such as grain shape, panicle length and seed shattering, play important roles in grain yield and harvest. In this study, the cloning and functional analysis of PANICLE TRAITS 2 （PT2）, a novel gene from the Indica rice Chuandali （CDL）, is reported. PT2 is synonymous with Growth-Regulating Factor 4 （OsGRF4）, which encodes a growth-regulating factor that positively regulates grain shape and panicle length and negatively regulates seed shattering. Higher expression of OsGRF4 is correlated with larger grain, longer panicle and lower seed shattering. A unique OsGRF4 mutation, which occurs at the OsmiRNA396 target site of OsGRF4, seems to be associated with high levels of OsGRF4 expression, and results in phenotypic difference. Further research showed that OsGRF4 regulated two cytokinin dehydrogenase precursor genes （CKX5 and CKX1） resulting in increased cytokinin levels, which might affect the panicle traits. High storage capacity and moderate seed shattering of OsGRF4 may be useful in high-yield breeding and mechanized harvesting of rice. Our findings provide additional insight into the molecular basis of panicle growth.

Clinical risk score for invasive fungal diseases in patients with hematological malignancies undergoing chemotherapy:China Assessment of Antifungal Therapy in Hematological Diseases (CAESAR) study

Invasive fungal disease (IFD) is a major infectious complication in patients with hematological malignancies.In this study,we examined 4889 courses of chemotherapy in patients with hematological diseases to establish a training dataset (n=3500) by simple random sampling to develop a weighted risk score for proven or probable IFD through multivariate regression,which included the following variables: male patients,induction chemotherapy for newly diagnosed or relapsed disease,neutropenia,neutropenia longer than 10 days,hypoalbuminemia,central-venous catheter,and history of IFD.The patients were classified into three groups,which had low (0-10,~1.2%),intermediate (11-15,6.4%),and high risk (> 15,17.5%) of IFD.In the validation set (n=1389),the IFD incidences of the groups were ~1.4%,5.0%,and 21.4%.In addition,we demonstrated that antifungal prophylaxis offered no benefits in low-risk patients,whereas benefits were documented in intermediate (2.1% vs.6.6%,P=0.007) and high-risk patients (8.4% vs.23.3%,P=0.007).To make the risk score applicable for clinical settings,a pre-chemo risk score that deleted all unpredictable factors before chemotherapy was established,and it confirmed that anti-fungal prophylaxis was beneficial in patients with intermediate and high risk of IFD.In conclusion,an objective,weighted risk score for IFD was developed,and it may be useful in guiding antifungal prophylaxis.

Regulation of Seed Vigor by Manipulation of Raffinose Family Oligosaccharides in Maize and Arabidopsis thaliana

Raffinose family oligosaccharides （RFOs） accumulate in seeds during maturation desiccation in many plant species. However, it remains unclear whether RFOs have a role in establishing seed vigor. GALACTINOL SYNTHASE （GOLS）, RAFFINOSE SYNTHASE （RS）, and STACHYOSE SYNTHASE （STS） are the enzymes responsible for RFO biosynthesis in plants. Interestingly, only raffinose is detected in maize seeds, and a unique maize RS gene （ZmRS） was identified. In this study, we found that two independent mutator （Mu）-interrupted zmrs lines, containing no raffinose but hyperaccumulating galactinol, have significantly reduced seed vigor, compared with null segregant controls. Unlike maize, Arabidopsis thaliana seeds contain several RFOs （raffinose, stachyose, and verbascose）. Manipulation of A. thaliana RFO content by overexpressing ZmGOLS2, ZmRS, or AtSTS demonstrated that co-overexpression of ZmGOLS2 and ZmRS, or overexpression of ZmGOLS2 alone, significantly increased the total content of RFOs and enhanced Arabidopsis seed vigor. Surprisingly, while overexpression of ZmRS increased seed raffinose content, its overexpression dramatically decreased seed vigor and reduced the seed amounts of galactinol, stachyose, and verbascose. In contrast, the atrs5 mutant seeds are similar to those of the wild type with regard to seed vigor and RFO content, except for stachyose, which accumulated in atrs5 seeds. Total RFOs, RFO/sucrose ratio, but not absolute individual RFO amounts, positively correlated with A. thaliana seed vigor, to which stachyose and verbascose contribute more than raffinose. Taken together, these re- sults provide new insights into regulatory mechanisms of seed vigor and reveal distinct requirement for RFOs in modulating seed vigor in a monocot and a dicot.

Algae (Raphidocelis subcapitata) mitigate combined toxicity of microplastic and lead on Ceriodaphnia dubia

Microplastics(MPs)have been recognized as a new class of emerging contaminants in recent years.They not only directly impact aquatic organisms,but also indirectly impact these organisms by interacting with background toxins in the environment.Moreover,under realistic environmental conditions,algae,a natural food for aquatic organisms,may alter the toxicity pattern related to MPs.In this research,we first examined the toxicity of MPs alone,and their effect on the toxicity of lead(Pb)on Ceriodaphnia dubia(C.dubia),a model aquatic organism for toxicity survey.Then,we investigated the effect of algae on the combined toxicity of MPs and Pb.We observed that,MPs significantly increased Pb toxicity,which was related to the increase in soluble Pb concentration and the intake of Pb-loaded MPs,both of which increased the accumulation of Pb in C.dubia.The presence of algae mitigated the combined toxicity of MPs and Pb,although algae alone increased Pb accumulation.Therefore,the toxicity mitigation through algae uptake came from mechanisms other than Pb accumulation,which will need further investigation.

Characteristics and model studies for fluoride and arsenic adsorption on goethite

Fluoride and arsenic are major anionic elements of concern in drinking water treatment. The effects of contact time, pH, surface loading and ionic strength on adsorption of fluoride and As（V） were investigated using batch methods. Adsorption of fluoride and As（V） onto goethite obeyed a pseudo second-order rate law. Through experimental data and adsorption kinetic analysis, the affinity of As（V） onto goethite was stronger than fluoride. Fluoride and As（V） uptake by goethite all decreased with pH increasing at the same surface loading; however, ionic strength had slight influence on their adsorption. A surface sites-species model was used to quantify the adsorption of fluoride and As（V） onto goethite as function of pH and surface loading. This model can satisfactorily predict their adsorption characteristics with several adsorption constants.

Engineering management for high-end equipment intelligent manufacturing

The high-end equipment intelligent manufacturing(HEIM) industry is of strategic importance to national and economic security. Engineering management(EM) for HEIM is a complex, innovative process that integrates natural science, technology, management science, social science, and the human spirit. Newgeneration information technology(IT), including the internet, cloud computing, big data, and artificial intelligence, have made a remarkable influence on HEIM and its engineering management activities, such as product system construction, product life cycle management, manufacturing resources organization, manufacturing model innovation, and reconstruction of the enterprise ecosystem.Engineering management for HEIM is a key topic at the frontier of international academic research. This study systematically reviews the current research on issues pertaining to engineering management for HEIM under the new-generation IT environment. These issues include cross-lifecycle management, network collaboration management, task integration management of innovative development, operation optimization of smart factories,quality and reliability management, information management, and intelligent decision making. The challenges presented by these issues and potential research opportunities are also summarized and discussed.

Haploidentical hematopoietic cell transplantation for severe acquired aplastic anemia: a case-control study of post-transplant cyclophosphamide included regimen vs. anti-thymocyte globulin & colony-stimulating factor-based regimen

Dear Editor,Haploidentical allogeneic hematopoietic stem cell transplantation(haplo-HSCT),a curative therapy for severe aplastic anemia(SAA)patients,has been used clinically for decades.Two models,not involving ex vitro T-cell depletion,have been adopted for haplo-HSCT in patients with SAA.The first is referred to as the"Beijing protocol"(Xu et al.,2017),and comprises a conditioning regimen using busulfex(BU),cyclophosphamide(CY).

Characterization of viromes within mosquito species in China

Mosquitoes are vectors of multiple disease-causing agents that cause worldwide outbreaks of serious infectious diseases in both humans and animals. These arboviral agents include Dengue virus (DENV), Zika virus (ZIKV), chikungunya virus, yellow fever virus, Japanese encephalitis virus (JEV),and Rift Valley fever virus. Thus, mosquitoes are key to the study of viral origin, spread, and the epidemic tendency of these infectious diseases (Hall and Macdonald, 2016).