“藏粮于地”战略下高标准农田建设模式研究*

高标准农田建设是我国“藏粮于地”战略的重要抓手,是确保粮食产能的重要支撑。在梳理大量参考文献、政策文件和标准规范的基础上,针对现阶段高标准农田建设存在管理体制不完善、空间潜力不足、投资标准偏低、建设质量不高等问题,总结归纳高标准农田建设模式总体构架,通过对我国高标准农田建设综合评价结果排名靠前和提升较快的省份开展高标准农田建设模式调查研究,围绕管理体制、规划布局、建设标准、资金保障以及实施管理方面,提出系统构建高标准农田建设模式的对策建议,为提高高标准农田建设质量作有益参考。     

基于Netty的农业物联网服务器系统设计

为了方便对温室环境的监控和控制,使用Netty网络框架设计了一个农业物联网服务器系统,能够简化物联网服务器端的开发,实现下位机与上位机的实时通信。本文阐述了该系统的工作原理和总体设计,以期为实现大棚农作物生长的智能化和信息化管理。     

饲养系统和日粮对羔羊屠宰性能和肌肉矿物质含量的影响

文章旨在探讨不同饲养系统和日粮对羔羊生长、屠宰性能及肌肉矿物质含量的影响。试验将平均体重为（13.97±0.55）kg的120只羔羊随机分为3组，每组4个重复，每个重复10只。T1组在室内饲喂基础浓缩料，每天补充100 g稻草，T2组在室内饲喂基础浓缩料，每天补充100 g稻草和锌硒复合矿物质（0.2 mg/d硒，50 mg/d锌），T3组在室外放牧，除了采食苜蓿草外，每天额外补充100 g稻草和100 g燕麦。试验时间为9周。结果：T1和T2组羔羊的末重、日增重、半胴体重、下肢深度、下肢重量、眼肌面积、颈、胸肌、肾重量均显著高于T3组（P＜0.05），但骨盆骨重量显著低于T3组（P＜0.05）。各处理组羔羊的可食用部分和骨盆肌肉重量无显著差异（P＞0.05）。T2组63 d羔羊血液硒含量较T1和T3组分别显著提高了19.83%和25.0%（P＜0.05），血液锌含量较T1和T3组分别显著提高了31.71%和45.91%（P＜0.05）。T3组羔羊肌肉钙含量较T1和T2组分别显著提高了8.79%和5.37%（P＜0.05）。T2羔羊肌肉硒和锌含量较T1和T3组分别显著提高了41.18%、65.52%和38.19%、46.15%（P＜0.05），T2和T3组羔羊肌肉钾含量较T1组分别显著提高了3.27%和4.28%（P＜0.05）。结论：在本试验条件下，放牧羔羊胴体的脂肪含量低于室内饲养的羔羊，室外放牧可以提高肌肉钙和钾含量，但肌肉硒含量降低。 [关键词]饲养系统|羔羊|屠宰性能|矿物质     

我国社会救助管理服务体系建设研究

我国社会救助体系不断完善的过程中涉及主体更多元、方式更多样。当前社会救助面临相关部门和组织多、信息复杂、经办分散、分类精准施救难度大等问题。基于我国社会救助模式的合理价值选择，提出管理服务体系建设的重要意义。进而分析社会救助在管理服务上面临的挑战和难题，从组织协调管理、信息网络系统、基层经办机构、社会参与机制四个方面提出构建多层次管理服务体系的思路。力求提高管理服务的效率和效能，促进互助共济社会救助共同体的形成，提升公众满意度，夯实我国民生保障基础。     

Large‐scale patterns of fish diversity and assemblage structure in the longest tropical river in Asia

Although the Mekong River is one of the world's 35 biodiversity hot spots, the large‐scale patterns of fish diversity and assemblage structure remain poorly addressed. This study aimed to investigate the fish distribution patterns in the Lower Mekong River (LMR) and to identify their environmental determinants. Daily fish catch data (i.e. from December 2000 to November 2001) at 38 sites distributed along the LMR were related to 15 physicochemical and 19 climatic variables. As a result, four different clusters were defined according to the similarity in assemblage composition and 80 indicator species were identified. While fish species richness was highest in the Mekong delta and lowest in the upper part of the LMR, the diversity index was highest in the middle part of the LMR and lowest in the delta. We found that fish assemblages changed along the environmental gradients and that the main drivers affecting the fish assemblage structure were the seasonal variation of temperature, precipitation, dissolved oxygen, pH and total phosphorus. Specifically, upstream assemblages were characterised by cyprinids and Pangasius catfish, well suited to low temperature, high dissolved oxygen and high pH. Fish assemblages in the delta were dominated by perch‐like fish and clupeids, more tolerant to high temperatures, and high levels of nutrients (nitrates and total phosphorus) and salinity. Overall, the patterns were consistent between seasons. Our study contributes to establishing the first holistic fish community study in the LMR.     

Beaver dams,streamflow complexity,and the distribution of a rare minnow,Lepidomeda copei

Freshwater fishes are threatened globally, and often too little is known about threatened species to effectively guide their conservation. Habitat complexity is linked to fish species diversity and persistence, and degraded streams often lack habitat complexity. Beaver Castor spp., in turn, have been used to restore streams and increase habitat complexity. The northern leatherside chub Lepidomeda copei is a rare, small‐bodied, drift‐feeding minnow that has anecdotally been observed to use complex habitats associated with beaver dams in the western United States. To investigate this anecdote, we conducted fish and habitat surveys, the latter focusing on quantifying habitat complexity, in a sub‐basin of the Upper Snake River Basin in the USA. Complementary generalised linear model and path analyses revealed that northern leatherside chub occurred more often at sites with complex streamflows, and streamflows were more complex when beaver dams were present and pools were deeper. Northern leatherside chubs were also more likely to occur when temperatures were warmer, aquatic macrophytes were abundant and stream channels were narrow and deep. The linkage between chubs, complex streamflows and beaver dams needs to be evaluated more broadly to completely understand its role in the rangewide status of the species. However, it does suggests that increased use of beaver reintroductions and dam analogues for stream restoration could be a boon for the northern leatherside chub, but such efforts should be monitored to determine their effectiveness to help adapt beaver‐based restoration approaches to best benefit the species.     

Vitrification of mouse two-cell and blastocyst stage embryos in simplified closed system using either a hemi-straw or a hollow fiber device

Two-cell stage and blastocyst stage mouse embryos were equilibrated in a medium containing 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 8–15 min. Vitrification was performed in a medium containing 0.5 M sucrose and either 15% EG + 15% DMSO, 17.5% EG + 17.5% DMSO, or 20% EG + 20% DMSO for 30 s. They were then placed either on a hemi-straw (HS) or a hollow fiber vitrification (HFV) device and vitrified by cooled air inside a 0.5-ml straw. In two-cell embryos, a 100% survival rate was obtained from all groups except the 20% HS group (P > .05). All vitrified two-cell groups showed similar rates of blastocyst development to that of fresh control group (P > .05), except 17.5% and 20% HFV groups, which were significantly lower than the other groups (P < .05). In the blastocyst embryos, the HFV groups were divided into two subgroups (non-collapsed; HFV-NC and collapsed; HFV-C blastocyst). Re-expansion rate in 15% HFV-NC, 17.5% HFV-NC, and 15% HFV-C groups was reduced (P < .05), whereas the rest were similar to control. In conclusion, we established a simplified, reliable, and closed system for HFV vitrification applying hemi-straw, which does not require skilled practitioners.     

Engineered-airlift pumps for aquaculture applications using multiphase flow analysis

Currently, very few aquaculture operations are employing airlift pump technology for water recirculation, aeration, and waste removal. This is likely due to the poor design and lower efficiency of traditional airlift design, the limited amount of research effort that has been invested in improving performance capabilities of air lift pumps and the general lack of awareness of the industry about the inherent advantages of airlift systems. A new efficient airlift pump is hydrodynamically designed by incorporating the Volume of Fluid (VOF) multi-phase model along with the K-ε turbulence model utilizing Computational Fluid Dynamics (CFD) tools. The pump is designed to offer a substantial reduction in total energy usage as well as an improved quality of the culture products in order to make it attractive to aquaculture industry. In this study, both numerical and experimental investigations were carried out for airlift systems operating under two different submergence ratios of 50% and 90% in a lab setting using 2.54 cm diameter pumps. Also, the performance of a large-scale pumps of 10.16 cm diameters were also tested in an aquaculture raceway to determine its effect on the operation. The numerical results were found to be in agreement with the experiments within ±20% which is considered very reasonable for multiphase flow analysis. The present study was found to present a great tool for modelling the airlift pump performance, and potentially proposing new designs.     

云南怒江傈僳族自治州古树名木资源现状调查

对怒江傈僳族自治州人为活动区域古树名木资源现状进行调查。结果表明:共记录到古树名木496株,涉及36科54属76种,其中有8种国家重点保护野生植物,分别为澜沧黄杉、秃杉、南方红豆杉、云南榧树、千果榄仁、红椿、光叶珙桐和香果树;怒江州古树名木主要分布在乡村街道及远郊野外,占总数的98.8%,63.6%的古树生长在海拔1500~1999 m;古树名木的生长环境及长势总体较好,但保护力度相对薄弱,应采取相关措施加强保护和管理。     

面向养殖水体分布差异的COD光谱法检测研究

面向养殖水体，传统光谱法对化学需氧量（Chemical Oxygen Demand，COD）检测模型构建的基础：源域（现有样本库）与目标域（检测地水体）间光谱数据独立同分布。但是当源域与目标域分布间存在差异时，由源域得到的低误差模型常在目标域上表现下滑。针对该问题，提出面向UV Vis光谱的域对抗训练网络（DAUVwpNet），将分布不同的源域和目标域数据映射至相同分布的特征空间中，使其在该空间的分布距离尽可能接近，从而在特征空间中对源域训练的目标函数也可以迁移至目标域上，以降低模型在目标域的误差。试验表明：面向同一批测试数据，DAUVwpNet的预测误差为0.78，要低于传统模型的预测误差（0.85）；DAUVwpNet预测值与实测值间相关系数为0.95，要高于传统模型的相关系数（0.89）。表明了该网络能够较好对齐两域特征空间数据分布，降低因分布差异带来的COD检测误差。