美国熊本牡蛎基础群体构建及生产性能评估

为了获得优良熊本牡蛎(Crassosrea sikamea)种质资源,于2015年从美国Taylor贝类养殖公司引入熊本牡蛎,采用2种配对方式构建了核心基础群体;以中国熊本牡蛎选育群体为对照,评估了美国熊本牡蛎引种的生产性能及可行性。结果表明,美国熊本牡蛎相对于中国群体而言,表现出生长较快,商品规格比率较高,但存活力较低的特点。经过1周年养成,美国熊本牡蛎较中国群体子代壳高提高了11.48%,总重提高了48.12%。评估表明,群体来源对子代生产性能造成了显著的影响,而配对策略尚未产生显著影响。本研究发现美国熊本牡蛎在中国华南沿海具有较好的生产性能,这为熊本牡蛎种质改良提供了宝贵的繁育材料,也为华南牡蛎产业提供了一个可选择的优良品种。     

污水资源在干旱区城市绿化中的应用研究——以乌鲁木齐市为例

乌鲁木齐市是一个资源型缺水城市,淡水资源的短缺已成为制约区域经济社会发展、生态环境改善的瓶颈因素.增加市区绿地面积的同时需要绿化乌鲁木齐周围大面积的荒山.在水资源匮乏的条件下,要因地制宜地进行绿化,并使绿化面积持续扩大,必须全面考虑绿化用水问题.对乌鲁木齐市的水资源总量、水资源开发利用现状、城市绿化现状及其发展规划等进行了一定的分析,然后结合该区干旱缺水的实际情况,进一步分析讨论了污水资源在城市绿化中应用的可行性,并提出了一些建设性建议.     

Characterization of supply of marine finfish species with potential for commercial growth in the United States

Global production of marine finfish has grown in total volume of production and the number of species farmed commercially, but there has been little production in the United States of marine finfish other than salmon and red drum. For most species considered to be ready for commercialization, there are few or no farms from which to evaluate the size of the market or to estimate revenues and costs necessary to assess economic feasibility. This present study takes a first step to fill this gap with an analysis of the existing supply of 20 marine finfish species identified as candidates for commercialization in the United States, as a proxy for effective demand (the volume of a product sold at the market equilibrium price). Secondary data from 1950 (where available) through 2019 were compiled on each species, including (1) global aquaculture production, (2) US aquaculture production, (3) US commercial landings, (4) US recreational landings, and (5) imports. Current effective market demand (measured as the sum of commercial landings, farmed production, and imports) was low, totaling 36.6 million kg across the 20 species, which is equivalent to less than 23% of the annual volume sold of US farmed catfish. Commercial landings for 17 of the 20 species exhibited declines, potentially offering opportunities for farmed product to capture market share by filling the increasing gaps in supply. The variability in commercial landings provides opportunities for farms to capitalize on their advantage in supplying product with a high degree of consistency of volume, size, delivery frequency, and quality. Several unknown factors suggest the need for follow-up studies on consumer preferences, degree of substitutability among finfish species, and effects of recreational landings on demand. An important limitation to prospective producers is the lack of species-specific import data for the generic categories of “flounder,” “bass,” and “snapper.” This supply analysis provides a foundational analysis for prospective producers, investors, and researchers interested in commercialization of these marine species.     

超高压食品处理技术在绿茶浓缩汁加工中应用的可行性

综述了超高压处理技术在食品加工中的应用概况,茶浓缩汁生产加工中面临的问题,以及超高压处理对食品微生物和品质生化成分的影响,并据此分析了超高压处理技术应用于绿茶浓缩汁加工的可行性。     

于桥水库水源地生态湿地系统建设可行性分析

作为天津市重要的饮用水水源地,于桥水库的水环境安全备受关注。为了保证城市供水安全,于桥水库生态环境综合治理势在必行。本文从消减入库污染物负荷和改善水库生态环境的角度出发,对于桥水库水源地生态湿地系统的建设场地、自然地质条件进行了详细分析,并对水源地生态湿地系统的布局及运行维护方案进行了设计,同时,分析了实施水源地生态湿地系统建设项目的综合效益。     

Techniques for the treatment, removal and disposal of host material during programmes for plant pathogen eradication

Eradication of plant pathogen incursions is very important for the protection of plant industries, managed gardens and natural environments worldwide. The consequence of a pathogen becoming endemic can be serious, in some cases having an impact on the national economy. The current strategy for eradication of a pathogen relies on techniques for the treatment, removal and disposal of affected host plants. There are many examples where these techniques have been successful but many where they have not. Success relies on a sound understanding of the biology and epidemiology of the pathogen and its interaction with the host. Removal and disposal of infected plant material for eradication and containment of plant and soil inhabiting fungal, bacterial and viral pathogens are reviewed by considering black Sigatoka of banana, apple scab, maize smut, fireblight, citrus canker and sharka disease of stone-fruit crops. In examining examples of dealing with plant pathogens and diseased host material around the world, particularly Australasia, various techniques including burning, burying, pruning, composting, soil- and biofumigation, solarization, steam sterilization and biological vector control are discussed. Gaps in the literature are identified and emphasize the insufficient detail of information available from past eradications. More effort is required to produce and publish scientific evidence to support the success or otherwise of techniques and suggestions for future research are proposed.     

基于生态保护目标的湿地生态需水研究

根据当前我国湿地面临的生态环境问题以及国内外有关湿地生态需水的研究进展, 结合湿地保护和管理目标, 提出了较为科学的、具有实际应用价值的生态需水概念、理论、计算原则及相关计算方法。基于湿地生态保护目标的湿地生态需水概念就是为解决和恢复湿地生态问题及实现湿地保护目标所需要的水量。计算需注意的地方主要有7个方面, 即:①维系湿地生态环境现状; ②维持新生湿地生态系统不再退化; ③恢复历史某个时期的湿地生态景观和功能; ④维持湿地基本特征或者某些具体目标; ⑤保护湿地生物多样性; ⑥保护不同级别濒危珍稀物种或特殊生态系统; ⑦实现国家发展计划。计算方法主要有:湿地分级法、水文生态法、模拟模型法及遥感解译法。     

宁夏WUA项目区实施“量水到户”的可行性分析

推广节水灌溉先进技术是农民用水协会(WUA)的一项主要职责,而供水到户,计量到户不仅是灌溉用水管理的客观要求,也是调动农民用水户节水积极性的有效技术手段。通过对宁夏WUA项目区的实地调研和近两年监测资料的整理与分析,就普遍关注的农民用水协会实施"量水到户"问题进行了探讨。针对项目区量测水现状以及存在的问题,提出了在农民用水协会内部推行"量水到组"并逐步实现"量水到户"目标的途径以及农业综合开发扶持农民用水协会持续发展的工作重点。     

并联机器人中柔顺关节代替传统关节可行性分析

在3-RRR平面并联机器人中,驱动杆和连杆之间的传统关节被柔顺关节代替,形成含有柔顺关节的并联机器人。基于含有柔顺关节的并联机器人动力学模型和传统关节并联机器人动力学模型,从理论上求解并对比了在并联机器人中加入柔顺关节前后动平台的轨迹、驱动力矩以及驱动杆的转角变化,同时通过实验对比了两者的动平台轨迹,验证了大范围宏观运动的3-RRR并联机器人中柔顺关节代替传统关节的可行性,为柔顺关节并联机器人的进一步研究打下了基础。     

南坪水库不同坝址选取方案的比较及可行性分析

实地调查了南坪水库库区和坝址选址的地质条件,对3种不同坝址地质进行了分析,结果得出方案3工程地质条件相对较好,且库容条件较好,运行管理较方便,因此,将其作为推荐方案。通过对南坪水库不同坝址选取方案的可行性分析,提出了安全、经济、合理的南坪水库地质条件,确定水库的建设标准及规模、类型,为其他同类工程建设提供了参考。