电子商务进农村能增强农业经济韧性吗?——基于电子商务进农村综合示范政策的实证研究

本文基于2010-2021年全国15个省份995个县的面板数据,考察电子商务进农村综合示范政策对农业经济韧性的影响。研究结果表明:电子商务进农村综合示范政策有助于增强农业经济韧性。在进行了一系列稳健性检验后,结果依然稳健。该政策的影响效应存在地理区位异质性、农业功能区异质性与电商发展水平异质性,其中,影响效应在长江经济带、粮食主销区与电商发展水平滞后的地区更为显著。进一步研究发现,电子商务进农村综合示范政策通过发挥农业产业集聚效应和特色农业扶持效应来增强农业韧性。政府应强化对试点县的服务与监督,因地制宜开展绩效评估,鼓励农业产业集群的蓬勃发展,进一步放大电商政策对农业经济韧性的积极影响。

Identification of cell surface markers for acute myeloid leukemia prognosis based on multi-model analysis

Given the extremely high inter-patient heterogeneity of acute myeloid leukemia(AML),the identification of biomarkers for prognostic assessment and therapeutic guidance is critical.Cell surface markers(CSMs)have been shown to play an important role in AML leukemogenesis and progression.In the current study,we evaluated the prognostic potential of all human CSMs in 130 AML patients from The Cancer Genome Atlas(TCGA)based on differential gene expression analysis and univariable Cox proportional hazards regression analysis.By using multi-model analysis,including Adaptive LASSO regression,LASSO regression,and Elastic Net,we constructed a 9-CSMs prognostic model for risk stratification of the AML patients.The predictive value of the 9-CSMs risk score was further validated at the transcriptome and proteome levels.Multivariable Cox regression analysis showed that the risk score was an independent prognostic factor for the AML patients.The AML patients with high 9-CSMs risk scores had a shorter overall and event-free survival time than those with low scores.Notably,single-cell RNA-sequencing analysis indicated that patients with high 9-CSMs risk scores exhibited chemotherapy resistance.Furthermore,PI3K inhibitors were identified as potential treatments for these high-risk patients.In conclusion,we constructed a 9-CSMs prognostic model that served as an independent prognostic factor for the survival of AML patients and held the potential for guiding drug therapy.

干熄焦提升机钢绳检修更换优化实践

本文总结以往经验优化钢绳更换项目从方案分析、讨论,细化、量化方案步骤,提高钢丝绳更滑效率,并对记录的钢绳更换步骤进行分析总结,为今后更换提升机钢绳奠定基础。

经椎间孔入路脊柱内镜下腰椎间盘切除术治疗极外侧型腰椎间盘突出的临床研究

目的探讨经椎间孔入路脊柱内镜下腰椎间盘切除术治疗极外侧型腰椎间盘突出(FLLDH)的临床疗效。方法回顾性分析2020年1月至2021年12月通过采用经椎间孔内镜下腰椎间盘切除术治疗FLLDH的24例患者,对比分析术前、术后1 d、术后3个月,以及末次随访时腰腿痛视觉模拟评分法(VAS)评分与Oswestry功能障碍指数(ODI)问卷表。采用末次随访改良MacNab评价标准评估疗效。结果24例患者均成功完成了手术及12~30个月的随访,平均随访时间为19.79个月,术后1 d、术后3个月及末次随访腰痛及腿痛VAS评分与ODI较术前均有改善,差异均有统计学意义(P<0.05)。术后24例患者中优17例、良4例、一般3例。其优良率为87.5%。结论经椎间孔内镜下腰椎间盘切除术治疗FLLDH是一种安全、有效的手术方式。

发展数字贸易能提升中国农产品出口效率吗?——基于农产品进口国的经验证据

【目的】研究数字贸易发展水平与农产品出口效率的关系,为探测中国农产品出口市场空间,优化中国农产品出口路径提供了新的思路。【方法】基于2010—2021年全球45个国家的数据,采用随机前沿方法实证考察数字贸易发展水平对中国农产品出口效率的影响。【结果】(1)农产品进口国数字贸易发展水平的提高对中国农产品的出口效率有显著的促进作用,效率促进作用在谷物产品、水产品和油料产品这类大宗农产品的贸易中表现尤为显著。(2)农产品进口国完善基础设施建设、优化海关环境、提高金融交付能力与创新能力有助于中国农产品出口效率的提升。(3)中国农产品在非洲、南美洲和欧洲市场具有较大的出口潜力。【结论】要加强与数字贸易强国的合作,积极进行数字援助,缩小数字鸿沟,以数字技术提升中国农产品出口效率。

油气田压力类计量器具现场检测影响因素探讨

探讨了油气田压力类计量器具现场检测的影响因素,从环境温度、振动、安装高度等方面进行试验分析,现场检测时需要控制环境温度、压力计量器具出现高度差时通过数据修正的方式降低影响,出现振动时应加装减振装置,为压力类计量器具现场检测提供了依据和参考,确保压力计量器具现场检测的准确性及可靠性。

全自动驾驶模式下城市轨道交通车辆专家诊断系统研制

本文基于计算机辅助、车载通信、网络控制技术,搭建MVB+以太网的车辆数据收集平台,结合地面终端系统的分析处理,研制全套全自动驾驶模式下城市轨道交通车辆专家诊断系统。通过专家诊断系统对车辆状态数据的实时采集及分析,实现对列车运行状态的实时监控及车辆子系统的健康管理,为运维人员处理车辆故障提供指导。

清泉活水 荡涤乾坤--论李吉提当代音乐创作评论的七个“度”

李吉提数十年来的理论研究着力于音乐分析和音乐评论两大领域。就其大量音乐评论成果而言,她站在世界音乐文化的高度,坚持历史的维度、东西文化的视角和作曲技术理论的立场,引领“兼评论、兼分析”的专业性乐评范式,成就了她音乐评论的深度、广度、态度、温度、厚度、速度和高度。她以经年积累而创构的中国当代音乐创作评论之观念、方法、风格及学术思想,堪称中国音乐学术界的一股“清泉”和“活水”,在促进当代音乐评论学科发展及相关理论建设方面,形成勇开风气之先而荡涤乾坤的重要影响。

高效高稳定Rb_(2)SiF_(6)∶Mn^(4+)红光单晶

激光照明是下一代大功率固体照明重要的发展方向之一。目前,主流白光激光器件所采用的黄光/绿光陶瓷或晶体的发射光谱中红光组分不足,使得采用这类单一材料的激光照明器件色温偏高、显色指数较低。本文报道了液相法制备的高效率高稳定的Rb_(2)SiF_(6)∶Mn^(4+)(RSFM)红光单晶,该材料具有宽带蓝光吸收(~450 nm)和窄带红光发射(~630 nm)特征,外量子效率达55.8%。利用该材料组装的暖白光激光照明器件在7 W/mm^(2)功率密度激发下,光效达104.3 lm/W、色温为2633 K、显色指数为78.3。研究表明,高性能Mn^(4+)激活氟化物红光单晶有望促进暖白光激光照明应用。

基于土地景观格局的重庆市永川区生态风险评价

[目的]分析重庆市永川区土地景观格局变化下的生态风险水平和时空变化规律,为该地区的土地结构优化和生态空间规划提供科学依据和理论基础。[方法]以行政村为评价单元,利用拐点识别法确定适宜空间粒度,然后借助景观格局指数构建生态风险指数,同时运用空间自相关和冷热点分析永川区土地景观生态风险的时空变化。[结果]①永川区景观格局的适宜空间粒度为60 m。②研究期间,永川区生态安全状况趋于好转,低等级风险区以茶山竹海街道为中心向东南、西南延伸,高等级风险区以五间镇、宝峰镇等为中心向外扩张。③生态风险全局Moran’s I值分别为0.4472,0.4446,0.3722,呈正相关性,局部高高聚集区和热点区皆以团聚状分布于永川西北、西南和南部地区并有所扩张,低低聚集区和冷点区均以带状分布于茶山竹海街道等地并向东南延伸。[结论]虽然永川区生态安全状况趋于好转,但城周与区界附近乡镇生态风险波动较大,应成为未来生态治理的重点区域。

椎体成形术后新发椎体压缩性骨折的影响因素

椎体成形术是治疗骨质疏松性椎体压缩性骨折的有效方法,但术后常发生新的椎体压缩性骨折。近年来,虽然学者们围绕椎体成形术后新发椎体压缩性骨折进行了大量的研究,但目前对其影响因素仍存争议。比较常见的观点是,患者自身因素以及包括骨水泥的性能、注入量、分布在内的骨水泥相关因素和手术自身因素等是椎体成形术后新发椎体压缩性骨折的重要影响因素。本文从这些方面进行了综述,为临床降低椎体成形术后新发椎体压缩性骨折的风险提供参考。

水体铜对鲤肠道菌群结构及免疫力的影响

为了解水体重金属铜对鲤肠道菌群多样性、结构及免疫力的影响,以不同质量浓度的水体铜胁迫鲤56d,对鲤肠道菌群α多样性、β多样性、基于属水平的群落组成结构及肠道免疫调控因子和紧密连接蛋白的基因表达进行了分析.结果显示,0.14mg·L-1、0.28mg·L-1处理组与对照组相比,α多样性指数有显著性下降(P<0.01),主成分分析(PCA)显示两处理组与对照组群落组成区分明显,优势菌群发生明显变化;同时,两处理组肠道免疫调控因子Il-1β,IL-8,TNF-α及信号分子NF-κB基因表达有显著增加(P<0.01),肠道紧密连接蛋白Claudin-3,Claudin-c及免疫调控因子IL-10、信号分子TOR基因表达有显著下降(P<0.01).结果表明:中、高质量浓度水体铜胁迫显著降低了鲤肠道菌群的多样性,改变了结构组成,对鲤肠道上皮免疫屏障造成了损伤.

基于数据挖掘法探讨《世医得效方》中治伤方剂的用药规律

目的:探讨《世医得效方》中治伤方剂的用药规律。方法:收集《世医得效方》中第18卷“正骨兼金镞科”中的治伤方剂,建立标准化方药数据库。采用中医传承计算平台(V3.0)统计纳入方剂中药物的使用频次、功效、药性、药味及归经,采用SPSS Modeler 18.0软件对其中的高频药物进行关联规则分析,采用SPSSS tatistics 26.0软件对其中的高频药物进行聚类分析。结果:共收集79首方剂,其中内服方剂40首、外用方剂39首,共涉及154味中药。内服中药115味,累计使用频次278次,使用频次≥4的中药共21味,居于前5位的中药依次为当归、川芎、乳香、大黄、甘草;外用中药81味,累计使用频次135次,使用频次≥3的中药共15味,居于前5位的中药依次为铅丹、白芷、枫香脂、地黄、生姜。《世医得效方》治伤方剂中内服中药多采用活血化瘀、补虚、解表类药物,外用中药主要以解表、清热、活血化瘀类药物为主;药物多归肝、脾、心经,药味多辛、苦;内服药的药性偏温、平,外用药的药性偏温、寒。对使用频次≥4的21味内服中药进行关联规则分析,得到10条关联规则,涉及10个核心药物组合,分别为川芎→当归、没药→乳香、苏木→当归、白芍→当归、自然铜→没药、肉桂→当归、白芷→木香、白芷→川芎、白芷→当归、白芍+川芎→当归;对使用频次≥3的15味外用中药进行关联规则分析,得到10条关联规则,涉及10个核心药物组合,分别为川芎→白芷、半夏+生姜→黄柏、半夏+黄柏→生姜、生姜+黄柏→半夏、枫香脂+铅丹→石膏、枫香脂+石膏→铅丹、枫香脂+铅丹→白芷、铅丹+白芷→枫香脂、枫香脂+石膏→白芷、石膏+白芷→枫香脂。聚类分析结果显示,使用频次≥4的21味内服中药可聚为5类,第1类包括白芷、紫金皮、木香、白芍、地黄、川芎,合用能补血活血、行气止痛;第2类包括草乌、川乌、麝香、苏木、铅丹、大黄,合用能活血止痛;第3类包括白术、沉香、甘草、肉桂、生姜,合用能温补脾肾、行气止痛;第4类仅包括当归,能补血活血;第5类包括没药、自然铜、乳香,合用能活血止痛、生肌接骨。使用频次≥3的15味外用中药可聚为4类,第1类包括牛膝、紫金皮、刘寄奴、黄柏、川芎,合用能活血化瘀;第2类包括生姜、半夏、地黄,合用能解毒散结;第3类包括龙骨、水松皮、降真香,合用能降气收敛;第4类包括白芷、枫香脂、铅丹、石膏,合用能收敛生肌。结论:《世医得效方》中治伤方剂多采用辛温之药,常从肝、脾、心论治,其中内服方剂以活血化瘀、补血活血、行气止痛为主要治法,而外用方剂以解表清热、活血消肿、收敛生肌为主要治法。

下龙湾地区根际土壤可培养原核微生物多样性研究

[目的]下龙湾位于越南东北部广宁省,属于典型的喀斯特地貌,拥有独特的生态系统,获取其可培养原核微生物并进行多样性分析评价,对获取具有产业化应用前景的微生物资源有重要意义。[方法]本研究基于微生物纯培养技术,以越南下龙湾地区植物根际土壤样本为研究对象,对细菌和放线菌进行分离、纯化,并基于16S rRNA基因测序结果,通过序列比对、系统发育分析和多样性指数分析,对所获纯培养物进行多样性检测。[结果]共获得266个菌株,分属于12个目29个科54个属,Shannon-Wienner生物多样性指数(H′)为6.970,Simpson物种多样性指数(D)为0.987,Shannon物种均匀度指数(E)为1.384,Margalef物种丰富度指数(dMa)为27.40。下龙湾地区根际土壤可培养原核微生物主要为放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria),其中芽孢杆菌属(Bacillus)、假单胞菌属(Pseudomonas)、链霉菌属(Streptomyces)为优势种。潜在新种占4%。[结论]下龙湾地区蕴含丰富的细菌和放线菌资源,可为微生物资源开发利用提供良好的菌种来源。

Analytical and Experimental Study of Free Vibration of Beams Carrying Multiple Masses and Springs

The structures in engineering can be simplified into elastic beams with concentrated masses and elastic spring supports. Studying the law of vibration of the beams can be a help in guiding its design and avoiding resonance. Based on the Laplace transform method, the mode shape functions and the frequency equations of the beams in the typical boundary conditions are derived. A cantilever beam with a lumped mass and a spring is selected to obtain its natural frequencies and mode shape functions. An experiment was conducted in order to get the modal parameters of the beam based on the NExT-ERA method. By comparing the analytical and experimental results, the effects of the locations of the mass and spring on the modal parameter are discussed. The variation of the natural frequencies was obtained with the changing stiffness coefficient and mass coefficient, respectively. The findings provide a reference for the vibration analysis methods and the lumped parameters layout design of elastic beams used in engineering.

DDAH2(-449 G/C) G allele is positively associated with leukoaraiosis in northeastern China: a double-blind, intergroup comparison, case-control study

Cerebrovascular endothelial dysfunction is involved in the progression of leukoaraiosis. Asymmetric dimethylarginine is a competitive inhibitor of nitric oxide, which is highly expressed in patients with leukoaraiosis. Dimethylarginine dimethylaminohydrolase(DDAH) is a hydrolytic enzyme that is primarily responsible for eliminating asymmetric dimethylarginine, and it plays a role in the pathogenesis of cardiovascular and cerebrovascular diseases. The DDAH2 subtype is expressed in organs rich in induced nitric oxide synthase, including the heart, the placenta, and the cerebral endothelium during cerebral ischemia, in the stress state, or under neurotoxicity. Overexpression of the DDAH2 gene can inhibit asymmetric dimethylarginine-induced peripheral circulating endothelial cell dysfunction. However, it is unknown whether this polymorphism regulates plasma asymmetric dimethylarginine levels in patients with leukoaraiosis. In this doubleblind study, we recruited 46 patients with leukoaraiosis and 46 healthy, matched controls. Plasma asymmetric dimethylarginine levels were determined using enzyme-linked immunoassays. Genomic DNA was isolated from whole blood samples, and polymerase chain reaction, Sma I restriction enzyme digestion, restriction fragment length polymorphisms, and agarose electrophoresis were used to detect DDAH2(-449 G/C) gene polymorphisms. The results revealed that 95.65% of leukoaraiosis patients had recessive genetic models(GG and CG), while 89.13% of healthy control subjects had dominant genetic models(CC and CG). There was a significant difference in the genotype composition ratio between leukoaraiosis patients and healthy controls(P = 0.0002). The frequency of G alleles in the leukoaraiosis patients(71.74%) was significantly higher than in healthy controls, whereas the frequency of C alleles was lower(χ~2 = 13.9580, P = 0.0002). Furthermore, asymmetric dimethylarginine concentrations in subjects with the GG genotype were significantly higher than in subjects with the CG and CC genotypes(Kruskal–Wallis H = 24.5955, P < 0.0001). In addition, the GG genotype of DDAH2(-449 G/C) was more common in patients with leukoaraiosis. These findings suggest that the G allele of DDAH2(-449 G/C) is a risk factor for leukoaraiosis morbidity and is correlated with high levels of asymmetric dimethylarginine. This study was approved by the Institutional Ethics Committee of the 2~(nd) Affiliated Hospital of Harbin Medical University of China(approval No. KY2016-177) on July 28, 2016.

Experimental and Numerical Investigations on Vibration Characteristics of a Loaded Ship Model

In this paper, the vibration characteristics of the structure in the finite fluid domain are analyzed using a coupled finite element method. The added mass matrix is calculated with finite element method （FEM） by 8-node acoustic fluid elements. The vibration characteristics of the structure in the finite fluid domain are calculated combining structure FEM mass matrix. By writing relevant programs, the numerical analysis on vibration characteristics of a submerged cantilever rectangular plate in finite fluid domain and loaded ship model is performed. A modal identification experiment for the loaded ship model in air and in water is conducted and the experiment results verify the reliability of the numerical analysis. The numerical method can be used for further research on vibration characteristics and acoustic radiation problems of the structure in the finite fluid domain.

Optimal Control of a Beam with Discontinuously Distributed Piezoelectric Sensors and Actuators

Because of its light weight, broadband, and adaptable properties, smart material has been widely applied in the active vibration control （AVC） of flexible structures. Based on a firstorder shear deformation theory, by coupling the electrical and mechanical operation, a 4-node quadrilateral piezoelectric composite element with 24 degrees of freedom for generalized displacements and one electrical potential degree of freedom per piezoelectric layer was derived. Dynamic characteristics of a beam with discontinuously distributed piezoelectric sensors and actuators were presented. A linear quadratic regulator （LQR） feedback controller was designed to suppress the vibration of the beam in the state space using the high precise direct （HPD） integration method.

The combination therapy of imatinib and dasatinib achieves long-term molecular response in two imatinib-resistant and dasatinibintolerant patients with advanced chronic myeloid leukemia

For patients with chronic myeloid leukemia（CML） failing imatinib therapy,second-generation tyrosine kinase inhibitors（TKIs） are recommended.Here,we describe two patients with advanced CML who failed imatinib therapy and did not tolerate the recommended dose of dasatinib,but then achieved a major molecular response with the combination of imatinib and dasatinib with no significant extramedullar/ toxicity.Our observations suggest that combination of TKIs may provide an additive/synergistic antileukemic effect.

National Characteristics and Art Composition Characteristics of Tujia Brocade Art

As one of China's national minorities, Tujia nationality has exerted an important role in the development course of modern national culture. In the development course of national culture of Tujia nationality, its brocade art inherited generation by generation has been extensively applied in art inheritance in modern society. It has also been applied in practical teaching to manifest the unique style and special artistic expression of Tujia brocade art. Under such a context, it is necessary to strengthen analysis on its national characteristics in the art development course and art composition characteristics. For this purpose, this paper makes special analysis on the national characteristics and art composition of Tujia brocade art in the sequence of analysis on the basic components of Tujia brocade art, analysis on its national characteristics and then detailed analysis on its composition characteristics. The author hopes to help people to understand the unique characteristics and results of Tujia brocade art after the analysis in this paper.