GPS RTK的工作原理及在公路工程中的应用浅析

本文结合近几年的工程应用介绍了GPS RTK(Real Time Kinematic)工作原理及其在实际公路工程中的应用,对其在公路工程中的优越性,作业方法等进行简单的介绍.     

问卷调查折射出的辽宁渔业竞争力问题研究

针对目前辽宁渔业所面临的竞争环境，借助国际竞争理论设计出含有宏观因素、水产部门产业环境及基础设施、渔业生产管理体制和渔业有关人员力量四大系统的竞争力评价模型并进行了广域问卷调查。结果表明，近年来，辽宁渔业竞争力在很多领域有了一定的提高和增强。但是，在政策制度、管理体制和支撑体系等方面还折射出不少问题，制约着整个渔业竞争力的提升。基于此，提出了建立健全渔业保险制度和渔业贷款制度、提升渔业劳动者技术水平、加强养殖业者自律性、进一步制定渔用柴油油价上涨对策等一系列政策建议。     

我校学生阅读状况调查与分析

一个学生综合素质的提高,仅局限于课本知识的学习是远远不够的。因此,要想提高学生的素养、拓展知识面,就应该了解其在课外阅读方面的基本情况,课外阅读的方法,从而提出合理化建议,有针对性的给予指导和帮助,使学生对课外阅读产生兴趣,养成课外阅读的习惯,从中获取知识,受到熏陶。     

Can giant clam (Tridacna squamosa) populations be restored on Singapore's heavily impacted coral reefs?

• 1. Giant clams have been a sustainable resource for millennia, but unregulated harvesting has led to local extinctions within the Indo‐Pacific region. Giant clam mariculture can produce large numbers of juveniles for restocking wild populations where natural recruitment is low or absent.
• 2. Singapore is surrounded by more than 60 small islands, many with fringing reefs. These reefs, however, experience increased turbidity and sedimentation resulting from massive coastal development projects and regular dredging of shipping lanes.
• 3. Seven reefs off Singapore's southern islands were surveyed (9670 m²) for giant clams. Also, an experiment was conducted to determine the growth of Tridacna squamosa reared in aquaria under three light treatments: ～50% ambient photosynthetically active radiation (PAR); ～25% ambient PAR; and ～12% ambient PAR. Finally, 144 clams (T. squamosa) were transplanted to four reefs around Singapore to study survival and growth in a heavily impacted environment.
• 4. A total of 23 adult clams from three species were found during the survey, representing a mean density of 0.24 per 100 m². Most clams were found at Raffles Lighthouse, Singapore's ‘best’ reef. No juvenile clams were encountered. In the aquarium experiment, clam growth was significantly different among the three light treatments, with growth greatest in the ～50% ambient PAR treatment. Of the 144 transplanted clams, 116 (80.6%) were recovered after 7 months. All specimens had increased in size, with growth rates among reefs ranging from 3.3 mm month^?1 (SD=1.3 mm) to 4.8 mm month^?1 (SD=1.6 mm).
• 5. Results suggest that, despite high levels of sedimentation and turbidity on Singapore's reefs, giant clams can survive and grow well. Restocking efforts using maricultured clams may be effective in enhancing the dwindling local populations. It is not clear, however, whether a self‐sustaining community can be established as high sedimentation may hinder larval settlement and survival.

Copyright © 2007 John Wiley & Sons, Ltd.     

不同生态环境下散养鸡寄生虫区系调查

对榆林市不同生态环境下散养鸡的寄生虫进行比较详细的调查.发现鸡寄生虫14种,隶属8科10属,其中外寄生虫6种,分别属于3科5属,鸡内寄生虫8种,分别属于5科5属,其中线虫5种,绦虫3种,吸虫1种.分析了各类虫种的感染率、感染强度及优势虫种,并对不同生态环境下的鸡寄生虫感染情况进行了分析对比;在调查寄生虫感染原因的基础上,提出了防制措施.     

A case-control study to identify farm factors affecting fertility of dairy herds: univariate description of factors

Objective To identify farm factors which were associated with reproductive performance in dairy herds in New South Wales.
Procedure A survey was administered by face to face interview to examine the responses of producers drawn from 757 herds, which used the New South Wales Agriculture Department Dairy Herd Improvement scheme. A case-control approach was used to select a total of 126 herds from the first (top group - cases) and fourth quartiles (low group - controls) for intercalving interval.
Results We found that the estimated interval from calving to first mating was significantly different between groups (P = 0.03) and that the groups significantly differed in both their target for interval to first mating (P = 0.02) and their perceived optimum time for first mating (P = 0.04). Other factors associated with a longer intercalving interval included, use of embryo transfer programs (P = 0.08), younger managers (P = 0.02), fewer breedings per day (P = 0.01), a greater number of people detecting heats (P = 0.07), but less hours spent detecting heats while handling the cows (P = 0.11), and a failure to vaccinate bulls for campylobacteriosis (P = 0.14).
Conclusions Managers of herds with poorer reproductive performance did not intend to mate cattle as soon after calving as managers with better reproductive performance, were not as active in seeking veterinary advice on reproduction, and were attempting to treat reproductive diseases and disorders themselves.     

林区道桥工程的时代新技术影响与机遇

从宏观视角，针对林区道桥工程时代新技术影响，分析提出了“两大三高”特征、个性化、虚拟工作平台等问题，以及带给道桥工程专业人员的挑战与机遇。     

Epidemiological Cut-off Values (ECOFFs) of Salmonella from Chicken Intestinal Tract for Three Animal-specific Antibiotics

In order to establish epidemiological cut-off values (ECOFFs) of Salmonella for three animal-specific antibiotics (florfenicol,apramycin and danofloxacin) in Guangdong province.A total of 166 strains of Salmonella isolates from chicken intestinal tract from veterinary clinics and farms in Guangdong province in 2017 were recruited in this study,the minimum inhibitory concentrations (MIC) of florfenicol,apramycin and danofloxacin were determined in triplicate for each bacterial strain using the agar dilution method on Mueller-Hinton agar plates according to the CLSI reference method (CLSI-M100-S26).ECOFFs were calculated for the MIC data sets by application of nonlinear regression analysis,NRI(normalized resistance interpretation) and ECOFFinder software.MIC distribution of florfenicol,apramycin and danofloxacin against Salmonella from 2 to >512,4 to >512 and 0.015 to 64 μg/mL,respectively.MIC₅₀ and MIC₉₀ for apramycin,florfenicol and danofloxacin were 256 and >512,16 and >512,0.5 and 16 μg/mL,respectively.MIC distribution of apramycin and florfenicol presented obvious unimodal shape,while that of danofloxacin was a discontinuous multi-peak.The ECOFFs of florfenicol,apramycin and danofloxacin were recommended to be 16,16 and 0.125 μg/mL,respectively.In present study,the ECOFFs of Salmonella from chicken intestinal tract for apramycin,florfenicol and danofloxacin were determined,which provided scientific basis for resistance surveillance.     

壶瓶山自然保护区华南虎野外调查及栖息地评价

湖南省壶瓶山是森林和野生动物类型的国家级自然保护区,是近几年发现华南虎Panthera tigris amoyensis证据较多的区域.中美华南虎联合调查队于2001年10～12月采用访问调查法、样带调查法、痕迹调查法和红外线自动照相技术等目前国际国内通用的方法和技术,对该保护区进行了调查.此次调查虽未得到华南虎存在的确切证据,但较系统地调查了该区域的生境状况,初步评价了华南虎的生存环境.该区域历史上是华南虎分布较多的区域.经分析,目前仍具备华南虎生存的基本条件,是以后实施华南虎重引入工程较为理想的试验基地.表2参13     

校园植物信息的数字化采集与校园植物电子杂志的制作——以内蒙古大学创业学院为例

为了深入了解内蒙古大学创业学院校园植物资源情况,并利用校园资源丰富《生态学》课程教学,通过实地调查统计、文献调查、植物志检索结合的方法,对学院校园植物的种类、数量、分布及植物相关情况进行系统的调查研究,整理出本校的植物名录,并制作植物检索表,且制作了基于二维码技术的内蒙古大学创业学院校园植物电子杂志。经调查统计得岀,截至2019年6月31日,内蒙古大学创业学院校园现有植物22科37属41种,其中裸子植物5种,被子植物36种.草本19种,乔木12种,灌木8种,藤本2种。目前,校园植物资源主要是作为园林观赏美化环境使用,在营造校园文化、创建地域特色、完善相关课程建设等方面的价值还有待挖掘,具有较大的开发潜力。校园植物不仅是作为景观资源来使用,也能与相关学科的教学、植物相关知识的普及联系起来,发挥出更大的作用。