网络远程招生方式前后三年脑血管病方向统招硕士研究生生源情况分析

目的 通过对比网络远程招生与非网络远程招生方式下脑血管病方向统招硕士研究生的一般情况和成绩等信息,探讨网络远程招生方式对生源质量的影响。方法 以首都医科大学附属北京天坛医院2017-2022年脑血管病方向的统招硕士研究生为研究对象,根据招生方式将其分为两组,2017-2019年招收的统招硕士研究生为非网络远程招生组,2020-2022年招收的为网络远程招生组。本研究主要通过历年的研究生复试名单来获取研究数据,收集的信息包括考生的性别、年龄、民族、毕业院校、是否是应届生等基本信息以及其初试成绩和复试成绩,并对两组考生的上述指标进行差异化分析。结果 2017-2022年,首都医科大学附属北京天坛医院脑血管病方向的统招硕士研究生生源数量总体呈增长趋势。在所招收的统招硕士研究生中,女性88名(33.98%),比例低于男性,民族以汉族(246名,94.98%)为主,来源以应届毕业生(203名,78.38%)为主,网络远程招生组与非网络远程招生组相比,上述指标的差异均不具有统计学意义。网络远程招生组生源的平均年龄显著小于非网络远程招生组[(23.1±1.1)岁vs.(23.5±1.3)岁,P=0.014]。网络远程招生组神经病学和外科学(神经外科)专业的统招硕士研究生复试成绩均显著高于非网络远程招生组[神经病学,(255.5±12.3)分vs.(241.0±13.8)分,P<0.001;外科学(神经外科),(259.9±11.6)分vs.(249.3±13.1)分,P<0.001]。结论 网络远程招生的硕士研究生复试成绩在一定程度上优于非网络远程招生,为未来研究生招生形式提供了参考。

行车规章管理信息系统的研究与开发

行车规章是协调运输作业过程各部门、各工种作业、保证行车安全的基础。系统通过对行车规章全面准确的描述,实现了对行车规章增加、修改、删除、查询、统计、打印和多种辅助功能,简单易学,操作方便。

川产道地药材川射干系统开发研究综述(Ⅱ)

本文综述了五年来四川省中医药科学院对川产道地药材川射干所做的系统开发研究工作。

RCC满管斜坡输送系统的研究与运用

伴随着RCC施工技术的发展,经过工程技术人员的创新和变革,逐渐形成了以真空溜管为代表的斜坡RCC输送系统。近两年,随着RCC施工技术的创新,一种输送能力更强、使用更为简便的斜坡RCC输送系统--满管斜坡输送系统悄然兴起。本文介绍贵州光照水电站满管斜坡系统的研究、设计与运用。

运载火箭常规一、二级发动机电爆管可靠性提升及统型化升级换代研究

通过全面梳理运载火箭常规一、二级发动机使用的四种电爆管的设计输入、使用环境、对外接口等差异和共性,运用现行标准规范进行新要求的系统“三再”分析,识别在安全性、高温结构强度裕度及密封裕度等方面的薄弱环节,策划进行成熟度提升和统型化研究,统型后的两型产品可满足各项任务要求,产品可靠性得到了大幅提升,产品规格也得到压缩,在基础产品层面充分实现了产品的可靠性提升、统型和升级换代后,可以推广应用于长征系列火箭现役三级发动机(常规、氢氧)和姿控发动机;具备在武器领域常规发动机上的应用前景;满足较长一段时间内后续多种新型发动机的使用需求。

摄影艺术与大学英语教学统整研究

摄影艺术与大学英语教学有着天然的联系,却鲜见有相关统整研究。实际上,大学英语教学过程蕴含着极其丰富的艺术文化元素,实现大学英语教学与摄影艺术教育的统一和整合是提升英语教学和学生素质的重要途径。通过对两者的思辨与梳理,可以发现通而不同是摄影艺术与大学英语课堂教学的契合点,摄影艺术与大学英语教学互促共进、进行积极的双向互动,是激发大学生求知欲的必要过程,教育心理学显示,如果大学生对某事物感兴趣,就会认真地开动脑筋,用心思考,而且还会找到最有效的方法去获得必要的知识。因此,统整摄影艺术与大学英语教学,有利于大学生素质的培育,有利于充分调动学生的学习积极性并使之有对美的发掘力和鉴赏力,为学生终身发展奠基。

组织学习动力研究综述

评论性地回顾了组织学习动力研究的相关文献,梳理出组织学习动力研究的三种视角,即组织学习动力的微观还原研究;组织学习动力的转换研究;组织学习动力的张力研究。并对三类研究的贡献和局限进行了探讨。认为:在组织学习动力研究中,存在着一个观点的连续统(continum),即微观还原研究与张力研究分处两极,而转换研究则处于两极之间。野中等虽探讨了个体学习和组织学习的转化,但却回避了动力转化机制。这为我们尝试建立组织学习动力三维整合理论提供了条件。

Evaluation of soil nutrient status in poplar forest soil by soil nutrient systematic approach

A study was conducted to evaluate the soil nutrient status of poplar plantation by Soil Nutrient Systematic Approach (SNSA) in Jianghan Plain, Hubei Province, China. Soil physiochemical properties were analyzed in laboratory through collection soil samples of study site. Ten treatments of application different fertilizers were designed such as CK, optimum treatment (N, P, K, Zn), N(P, K, Zn), P(N, K, Zn), K(N, P, Zn), +Mg(N, P, K, Zn, Mg), Zn (N,P,K), +2P(N, 2P, K, Zn), +2K(N, P, 2K, Zn), and 2N+2P+2K(2N, 2P, 2K, Zn) for field experiment to test the effect on tree height, diameter (DBH) growth, and dry weight of poplar. The results showed that there was no significant difference in tree heights between treatments with different fertilizers, diameter growth of poplar trees in treatments of lack of N and Zn was significantly slower than that of trees in optimum treatment, and dry weight of poplar dropped significantly for treatment of CK as well as treatments without application N and Zn. It is concluded that N and Zn were main limiting factor for poplar growth. Results from laboratory analysis and field experiment were uniform per-fectly, which proved that SNSA was reliable in evaluating soil nutrient status of poplar plantation.

EQUATION OF MOTION FOR NOVEL FRICTION PENDULUM SYSTEM WITH DUAL ROLLERS

A novel friction pendulum system （FPS） with dual rollers is studied based on the multibody dynamics theory. By analyzing kinematic characteristics of the system, it is reduced to a one degree-of-freedom system. Then the equation of motion for the system is analytically derived by applying the theorem of the relative kinetic energy for a system of particles in differential form in the non-inertial reference system described as a nonlinear differential equation. In the case of the small angular displacement, the natural frequency of the corresponding undamped linear system is obtained, which is consistent with the experimental observation. The derived equation is useful for the study of dynamic characteristics of novel FPS, and its solution directly expedites the simulation of the system in a control loop, and further facilitates the semi-active control process including novel FPS.

Research on the Testing Methods of Instrumental System in the Marine Magnetic Survey

Testing methods of instrumental system in the marine magnetic survey have been studied in this paper, and the feasibility of each method has been testified by the observed data. The conclusion shows that the method brought out can effectively eliminate the systematic error caused by the instrumental system, and greatly improve the surveying precision and the reliability of the survey results.

Preliminary Study on Early-warning System of Ecological Security in Water-Level-Fluctuating Zone (WLFZ) of Three Gorges Reservoir

The area,the scope as well as some ecological environment questions in Three Gorges Reservoir was briefly introduced. Then its early warning-system frame was preliminarily constructed,which includes ecological security dynamic monitoring,ecological security appraisal,ecological security forecast and ecological security decision-making management. The synthetic evaluation indicator system of the ecological security quality were initially established,which includes ecological environment pollution,land use and land cover change,geological hazard and epidemic outbreaks. At the same time,29 evaluating indicators were selected,divides into the basic factors,response factors and inducing factors,which need to be Real-time monitored.

Vertical Distribution of Soil Carbon, Nitrogen, and Phosphorus in Typical Chinese Terrestrial Ecosystems

Characterization of the vertical distribution of soil organic carbon(C), nitrogen(N), and phosphorus(P) may improve our ability to accurately estimate soil C, N, and P storage. Based on a database of 21 354 records in 74 long-term monitoring plots from 2004 to 2013 in the Chinese Ecosystem Research Network(CERN), we built fitting functions to quantify the vertical distribution of soil C, N, and P(up to 100 cm depth) in the typical Chinese terrestrial ecosystems. The decrease of soil C, N, and P content with depth can be well fitted with various mathematical functions. The fitting functions differed greatly between artificial(agriculture) and natural(desert, forest, and grassland) ecosystems, and also differed with respect to soil C, N, and P content. In both the artificial and natural ecosystems, the best fitting functions were exponential functions for C, quadratic functions for N, and quadratic functions for P. Furthermore, the stoichiometric ratios of soil C, N, and P were ranked in descending order: grassland > forest > agriculture > desert, and were also associated with climate. This study is the first to build the fitting functions for the profile distribution of soil C, N, and P in China at a national scale. Our findings provide a scientific basis to accurately assess the storage of C, N, and P in soils at a large scale, especially for the integrative analysis of historical data.

Comparison of intestinal microbiota and activities of digestive and immune-related enzymes of sea cucumber A postichopus japonicus in two habitats

Sea cucumber A postichopus japonicus stock enhancement by releasing hatchery-produced seeds is a management tool used to recover its population under natural environmental conditions. To assess the suitability of releasing sites, we examined the microbiota of the gut contents of A. japonicus from two populations(one in sandy-muddy seagrass beds and one in rocky intertidal reefs) and the microbiota in their surrounding sediments. The activities of digestive and immune-related enzymes in the A. japonicus were also examined. The results indicated that higher bacterial richness and Shannon diversity index were observed in all the seagrass-bed samples. There were significant differences in intestinal and sediment microorganisms between the two habitats, with a 2.87 times higher abundance of Firmicutes in the seagrass bed sediments than that in the reefs. Meanwhile, Bacteroidetes and Actinobacteria were significantly higher abundant in the gut content of A. japonicus from seagrass bed than those from the reefs. In addition, the seagrass-bed samples exhibited a relatively higher abundance of potential probiotics. Principal coordinates analysis and heatmap showed the bacterial communities were classifi ed into two groups corresponding to the two habitat types. Moreover, compared to A. japonicus obtained from rocky intertidal habitat, those obtained from the seagrass bed showed higher lysozyme, superoxide dismutase and protease activities. Our results suggest that bacterial communities present in seagrass beds might enhance the digestive function and immunity of A. japonicus. Therefore, compared with the rocky intertidal reef, seagrass bed seems to be more beneficial for the survival of A. japonicus.

The impact of spatial autocorrelation on CPUE standardization between two different fisheries

Catch per unit of eff ort(CPUE) data can display spatial autocorrelation. However, most of the CPUE standardization methods developed so far assumes independency of observations for the dependent variable, which is often invalid. In this study, we collected data of two fisheries, squid jigging fishery and mackerel trawl fishery. We used standard generalized linear model(GLM) and spatial GLMs to compare the impact of spatial autocorrelation on CPUE standardization for different fisheries. We found that spatialGLMs perform better than standard-GLM for both fisheries. The overestimation of precision of CPUE estimates was observed in both fisheries. Moran's I was used to quantify the level of autocorrelation for the two fisheries. The results show that autocorrelation in mackerel trawl fishery was much stronger than that in squid jigging fishery. According to the results of this paper, we highly recommend to account for spatial autocorrelation when using GLM to standardize CPUE data derived from commercial fisheries.

Effects of seawater acidification on the early development of sea urchin Glyptocidaris crenularis

In this study, we evaluated the effects of CO_2-induced seawater acidification on fertilization, embryogenesis and early larval development in the sea urchin Glyptocidaris crenularis, that inhabits subtidal coastal areas in northern China. The range in seawater p H used in experiments was based on the projections of the Intergovernmental Panel on Climate Change(IPCC), to the year 2100. A natural seawater treatment(p H_(nbs) =7.98±0.03) and three laboratory-controlled acidified treatments(OA_1, ΔpH_(nbs) =-0.3 units; OA_2, ΔpH_(nbs) =-0.4 units; OA_3, ΔpH_(nbs) =-0.5 units) were used in experiments. Results show that:(1) there was a negative effect of seawater acidification on fertilization and on the percentage of abnormal fertilized eggs;(2) the size of early cleavage stage embryos decreased in a dose-dependent manner with decreasing p H;(3) both the hatching rate of blastulae and the survival rate of four-armed pluteus larvae decreased as pH declined;(4) larval abnormalities including asymmetrical development, changes in the length of skeletal elements, and corroded spicules were observed in all seawater acidified-treatments compared with the control. These data indicate that seawater acidification has a negative impact on the early development of G. crenularis, and supports the hypothesis that the response of echinoderms to ocean acidification(OA) varies among species. Further research is required to clarify the specific cellular mechanisms involved.

Comparative study of the hemolytic and cytotoxic activities of nematocyst venoms from the jellyfish Cyanea nozakii Kishinouye and Nemopilema nomurai Kishinouye

Two species of jellyfish, Cyanea nozakii Kishinouye and Nemopilema nomurai Kishinouye, have occurred offcoastal areas of the northeastern China Sea, Yellow Sea, and Bohai Sea in recent years. They influence marine ecosystem safety and fishery production, and also pose a risk to human health. The current study examined the hemolytic and cytotoxic activities of crude venoms extracted from the nematocysts of C. nozakii and N. nomurai. The results showed that there were more nematocysts on tentacles from C. nozakii than on tentacles of the same length from N. nomurai. The protein concentration per nematocyst extracted from N. nomurai was higher than that from C. nozakii. Both nematocyst venoms showed dose-and timedependent hemolytic activity on erythrocytes from chicken, pigeon, and sheep, with sheep erythrocytes being the most sensitive, with EC 50 values of 69.69 and 63.62 μg/m L over a 30-min exposure with N. nomurai and C. nozakii nematocyst venoms, respectively. A cytotoxic assay of both jellyfish venoms on A431 human epidermal carcinoma cells resulted in IC 50 values of 68.6 and 40.9 μg/mL after 24-h incubation, respectively, with venom from C. nozakii showing stronger cytotoxic activity than that from N. nomurai. The results of current study indicate that nematocyst venom from C. nozakii had stronger hemolytic and cytotoxic activities than that from N. nomurai and, thus, C. nozakii might be more harmful to the health of humans and other species than are N. nomurai when they appear in coastal waters.

The Current Situation of the Study on Twisted Tape Inserts in Pipe Exchangers

Heat transfer enhancement is used in many applications including heat exchangers, air conditioning, and refrigeration systems; hence many researchers have conducted experimental and numerical researches on heat transfer enhancement and have developed various techniques and methods. As a passive heat transfer technique, twisted tapes are widely used in various industries for their cost savings, lower maintenance requirements and the fact that they are easily set up. This paper introduces the principle of heat transfer enhancement of twisted tapes and reviews some of the experimental works done by researchers on this technique in recent years. The variously modified twisted tape inserts are widely researched and used to enhance heat transfer efficiency for heat exchangers. Twisted tapes perform better in low Re conditions and in square tubes. However, they could also cause higher pressure drops. Twisted tapes have great potential and profound implications if they can be used in traditional heat exchangers. Besides this, some correlations between the Nusselt number and friction factors are presented in this paper.

A novel male-associated marker for sex identification in Ussuri catfish Pseudobagrus ussuriensis

The Ussuri catfish Pseudobagrus ussuriensis is a promising aquaculture fish with sexual dimorphism that males grow 2–3 times faster than females. Therefore, all-male breeding could increase production of this fish, and sex-linked markers would be useful during the breeding process. In this study, a male-associated marker named PuGT54 was isolated in P. ussuriensis from a previously constructed microsatellite library. A total of 185 P. ussuriensis individuals containing 95 females and 90 males were used to test the usage of this maker. And results showed that sexes of all individuals were successfully identified, indicating the high reliability and accuracy of this marker for sex identifi cation. Furthermore, the male-specifi c fragment amplifi ed by this maker was cloned and sequenced, which was 118 base pairs in length. As homologous genes of this fragment was not found through BLASTn, detailed information of the male-specifi c fragment is unknown presently. Nevertheless, this marker would be helpful in conservation, breeding and ecological study of P. ussuriensis.