圆台型螺旋能量桩换热特性的模拟分析与验证

为了减少地源热泵的热干扰、提高其换热效率,该文提出了一种新型"圆台型螺旋能量桩(truncated cone helix energy pile,Co HEP)"。同时为了更加准确地模拟新型圆台型螺旋能量桩的换热特性,综合考虑初始土壤温度的不均匀性和土壤上表面动态边界条件,建立了三维数值模型,分析了不同锥角下圆台型螺旋能量桩的换热特性。结果表明:圆台型螺旋能量桩沿水流方向可以分成4个换热阶段:入口阶段→热短路阶段→小温差阶段→出口阶段。圆台型螺旋能量桩的底部热干扰现象较为严重,且锥角越大,底部热干扰越明显。相反,由于顶部螺旋半径较大,热干扰效应较弱。圆台型螺旋能量桩的单位管长换热量随着锥角的增加而线性增大,当系统运行时间为12 h时,锥角从0增加到10?再增加到20?,单位管长换热量增长率分别为2.54%和3.53%。新型圆台型螺旋能量桩单位管长换热量大于传统圆柱型螺旋能量桩,20?锥角条件下的单位管长换热量比传统圆柱型螺旋能量桩高了约6.16%。通过对新型圆台型螺旋能量桩的换热特性进行探析,相对于传统圆柱型螺旋能量桩,提升了换热效率,同时为后续的推广应用和工程设计奠定了理论基础。     

Do habitat measurements in the vicinity of Atlantic salmon (Salmo salar) parr matter?

Atlantic salmon, Salmo salar L., parr habitat characterisation is usually performed by in situ measures of key environmental variables taken at the exact fish location if the fishing gear allows precise pinpointing of this location, or in large sampling sections covering a river reach or mesohabitat, often ignoring variability in the immediate vicinity around individual fish. These data may be critically important in the development and validation of habitat preference models. The influences of seven increasing distances of measures, the variation of the number of considered measures and the depth of velocity measurement (bottom or 0.6 of the depth) in the calculations of HSI (Habitat Suitability Index) from a multiple‐experts fuzzy model of Atlantic salmon parr habitat were tested. When a parr was present, six measures collected in a 50‐cm radius around the fish to provide an average measure as input data and velocity measured at 60% of the depth gave the highest HSI values. These results show some potential for the use of an intermediate study scale, between micro‐ and mesohabitat, and questions how fish habitat conditions are currently measured.     

Towards the identification of ecological management units: A multidisciplinary approach for the effective management of bottlenose dolphins in the southern Iberian Peninsula

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Use of an acoustic telemetry array for fine scale fish behaviour assessment of captive Paiche,Arapaima gigas,breeders

As Arapaima gigas is one of the most valuable species for the growing production of Amazonian aquaculture, knowledge of its reproductive behaviour and its application to increase reproduction success in captivity is of great importance as no hormonal spawning induction technique exists for this species. An acoustic positioning system (LOTEK Inc.) was used to observe the interactions of adult fish to better understand the formation of mating pairs. Fish were placed in a 4,500 m² aquaculture pond over a 6‐month period in the IIAP field station of Pucallpa, Perú. This paper describes the methodological protocols used to set up and test the hydrophone array and presents the methodology used for the analysis of the huge amount of collected data. This methodology is illustrated by the analysis of a 6‐day period for a mating pair that showed a spawning event. The results indicated that male and female occupied mostly one preferential area in one pond edge where the nesting area is located. Different activity patterns were observed during the spawning event, with male and female being closer during the spawning day. The results also showed that male travelled less distance than female during the studied period. Finally these results demonstrated the suitability of such equipment to monitor fish interactions at fine spatial (sub meter) and temporal (5 s) scales in confined environments like aquaculture ponds.     

Global significance of seagrass fishery activity

Seagrass meadows support fisheries through provision of nursery areas and trophic subsidies to adjacent habitats. As shallow coastal habitats, they also provide key fishing grounds; however, the nature and extent of such exploitation are poorly understood. These productive meadows are being degraded globally at rapid rates. For degradation to cease, there needs to be better appreciation for the value of these habitats in supporting global fisheries. Here, we provide the first global scale study demonstrating the extent, importance and nature of fisheries exploitation of seagrass meadows. Due to a paucity of available data, the study used a global expert survey to demonstrate the widespread significance of seagrass‐based fishing activity. Our study finds that seagrass‐based fisheries are globally important and present virtually wherever seagrass exists, supporting subsistence, commercial and recreational activity. A wide range of fishing methods and gear is used reflecting the spatial distribution patterns of seagrass meadows, and their depth ranges from intertidal (accessible by foot) to relatively deep water (where commercial trawls can operate). Seagrass meadows are multispecies fishing grounds targeted by fishers for any fish or invertebrate species that can be eaten, sold or used as bait. In the coastal communities of developing countries, the importance of the nearshore seagrass fishery for livelihoods and well‐being is irrefutable. In developed countries, the seagrass fishery is often recreational and/or more target species specific. Regardless of location, this study is the first to highlight collectively the indiscriminate nature and global scale of seagrass fisheries and the diversity of exploitative methods employed to extract seagrass‐associated resources. Evidence presented emphasizes the need for targeted management to support continued viability of seagrass meadows as a global ecosystem service provider.     

Macrofungal diversity of holm-oak forests at the northern limit of their distribution range in the Iberian Peninsula

Given the current gap in knowledge concerning the macrofungal diversity of holm-oak forests at the northern limit of their distribution range and in the Basque Country, a mycocoenological study was conducted by sampling 23 randomly selected permanent plots from 6 holm-oak forests. To obtain a better understanding of the macrofungal diversity distribution pattern on a regional scale, forests from both the temperate and Mediterranean-type climate regions of the Basque Country were selected, covering all their phytocoenological variation. After 4 years of sampling, a total of 377 macrofungal species were collected: 209 ectomycorrhizal species, 86 humicolous saprotrophs, 40 saprotrophs on litter, 36 lignicolous saprotrophs, 3 coprophilous saprotrophs and 3 parasitic species. Species considered characteristic of this kind of forest, such as Cortinarius aurilicis, Cortinarius callochrous, Cortinarius ionochlorus, Hygrophorus leucophaeo-ilicis, Hygrophorus persoonii, Hygrophorus russula, Lactarius atlanticus, Lactarius ilicis, Leccinellum lepidum, were recorded all over the territory, but Mediterranean forests were richer in species and more productive in sporocarps than temperate ones. Species assemblage was found to change gradually at local scale from temperate to Mediterranean climate zones, and was distinct to each phytocoenological association with all species, with ectomycorrhizal species and with saprotrophs.     

Analysis of tofu‐related traits by a bench‐scale tofu production method and their relationship with agronomic traits in European soybean

European tofu manufacturers are becoming more and more interested in locally grown soybeans. A prerequisite for the development of European tofu cultivars is to improve our understanding of how the environment and genetics affect soymilk and tofu quality, as well as how quality and agronomic traits are correlated. This study was based on 215 recombinant inbred lines derived from two populations and grown at three locations that were evaluated for tofu traits in a bench‐scale tofu laboratory. The heritabilities of most of the evaluated tofu traits were moderately high with h² > 0.6. We observed significant genotypic variance components, but an even stronger contribution of the location. The network analysis of the evaluated traits was population‐dependent; however, the tofu traits were not associated with any of the agronomic traits. Collectively, our results indicate the potential to improve tofu‐related traits in European soybean. The bench‐scale tofu production method provides a valuable tool to test soybean lines in breeding programmes; however, the method needs to be further improved and automated to minimize errors due to the laboratory staff.     

基于田块尺度的高标准农田建设空间形态判别研究

鉴于高标准农田工程布局、结构具有自身特殊性以及相较于一般农田具有空间形态上的显著差异,本研究基于农田田块尺度,以《高标准农田建设通则》为评价出发点,从田块规模、田块形态、农田道路、灌排设施和农田防护等方面构建了一套高标准农田建设合规性评价指标体系,利用布尔型赋值方式和短板原理综合评价高标准田块建设的质量和状况,并以吉林省松原市土地整治项目区为例进行试验实证。研究表明:从农田建设规范的内涵出发,构建的评价体系能有效测度不同维度和不同方面的高标准农田建设效果;提出的方法体系可进一步挖掘高标准农田建设工程的短板,为下一步改进工程措施和提高建设的合理性提供依据;试验区契合与不契合高标准农田建设标准的田块分别占总面积的78.2%和11.8%。     

乡村转型视角下山地丘陵区农地规模经营影响因素与分区

乡村发展转型下,结合地理空间差异探讨农地规模经营,对厘清山地丘陵区规模经营条件空间差异及经营模式分区配置具有重要意义。以重庆市合川区太和镇为研究区,并以乡村转型发展为研究视角,运用Pearson分析方法对村域农地规模经营影响因素进行识别与探讨,构建评价指标体系对农地规模经营条件进行评价及分区。结果表明：水田面积比重、流转租金、农村剩余劳动力指数、灌溉保证率、道路网密度与农地规模经营呈显著正相关,地块细碎化程度、坡度及距城镇距离等与农地规模经营呈显著负相关;农地规模经营条件空间差异显著,可分为规模农业示范区、农业综合拓展区、山地农业特色区、生态农业发展区。因此,山地丘陵区农地规模经营应全面考量经营条件并引导经营模式分区配置。     

美国超长绒棉生产优势分析

该文明确了美国Pima棉种植具有以下优势:①唯一集中种植区土壤保水保肥性好、光热资源丰富;②物质装备与技术先进实用;③产量高、品质优,种植规模效益显著;④大型农业机械作业的现代化集约式农场经营模式可行可靠;⑤社会服务、政策支持系统高效,以及种植布局合理、品牌影响力大,实现了高产、优质与高规模效益同步目标.虽然该国Pima棉生产能被确认为全球超长绒棉生产的大国与强国,但与中国ELS生产相比,双方互有优势与特点.笔者分析认为:借鉴美国ELS生产经验,我国应运用现代育种技术,加快ELS品种综合遗传特性改良步伐,尽快选育适宜机采的ELS品种,积极研发全程轻简节本增效栽培新技术,改革ELS生产组织形式,大力发展社会化服务体系,调整优化ELS产业扶持政策,从而从根本上提高我国ELS国际市场竞争力.