Leveraging flow mechanics to determine critical process and scaling parameters in a continuous viral inactivation reactor

A continuous viral inactivation (CVI) chamber has been designed to operate with acceptable residence time distribution (RTD) characteristics. However, altering the CVI's geometry and operation to accommodate the scale was not obvious. In this work, we elucidate the influence of Dean vortices and leverage the transition into the weak turbulent regime to establish relationships between input variables and process outputs. This study was targeted to understand and quantify the impact of viscosity, Dean number, internal diameter, and path length on the RTD. When the Dean number exceeds 70, radial mixing generated by the Dean vortices began to consistently alter the axial dispersive effects experienced by the pulse injection. Increasing to a Dean number of >100, the axial dispersive effects were dominated by the Dean vortices which allowed the calculation of the minimum and maximum residence time to be generated. This work provides a method to calculate operational solutions for a tubular incubation reactor in terms of path length, internal diameter, flow rate, and target minimum and maximum residence time specifications that assures both viral residence times while also establishing criteria to maximize product quality during continuous operation.     

格网尺度下典型旅游城市生态服务价值估算和时空分异特征——以三亚为例

以典型旅游城市三亚市为案例地,利用2006-2018年4期Landsat遥感影像数据,借助ENVI、ArcGIS平台定量识别土地利用演变特征,在1km×1km格网尺度下估算旅游地生态系统服务价值,并结合空间探索性数据分析揭示生态系统服务价值时空分异特征及其与旅游地发展的时空耦合关系。结果表明：（1）2006-2018年间,三亚市生态系统服务价值总量呈逐年下降趋势,由6.73×10⁹元降至5.76×10⁹元,累计减少9.78×10⁸元;（2）空间格局上,三亚市呈"南低北高"空间分异格局,2006-2018年增值区域连片分布于崖州区、天涯区、吉阳区南部区域,且呈逐年减少趋势,减值区域集聚于天涯区东北部、海棠区;（3）空间集聚上,生态系统服务价值截面各年份均呈显著空间正相关且相关性先降后增。高高集聚区位于天涯区北部区域,低低集聚区分布于沿海、海湾地区;（4）旅游发展与生态系统服务价值时空演化特征关联性较强。三亚市天涯区北部林地生态环境良好,生态系统服务价值略有下降但绝对数值稳定,是生态系统服务价值主要来源;旅游发展较为迅速的三亚湾、崖州湾以及海棠湾,相对增值区域较多,但绝对生态系统服务价值损失显著,严重滞后于其他区域。     

Greater Sage-Grouse Nesting Habitat: The Importance of Managing at Multiple Scales

Abstract: Considering habitat selection at multiple scales is essential to fully understand habitat requirements and management needs for wildlife species of concern. We used a hierarchical information-theoretic approach and variance decomposition techniques to analyze habitat selection using local-scale habitat variables measured in the field and landscape-scale variables derived with a Geographic Information System (GIS) for nesting greater sage-grouse (Centrocercus urophasianus) in the Powder River Basin (PRB), Montana and Wyoming, USA, 2003–2007. We investigated relationships between habitat features that can and cannot be mapped in a GIS to provide insights into interpretation of landscape-scale—only GIS models. We produced models of habitat selection at both local and landscape scales and across scales, yet multiscale models had overwhelming statistical and biological support. Variance decomposition showed that local-scale measures explained the most pure variation (50%) in sage-grouse nesting-habitat selection. Landscape-scale features explained 20% of pure variation and shared 30% with local-scale features. Both local- and landscape-scale habitat features are important in sage-grouse nesting-habitat selection because each scale explained both pure and shared variation. Our landscape-scale model was accurate in predicting priority landscapes where sage-grouse nests would occur and is, therefore, useful in providing landscape context for management decisions. It accurately predicted locations of independent sage-grouse nests (validation R² = 0.99) and showed good discriminatory ability with >90% of nests located within only 40% of the study area. Our landscape-scale model also accurately predicted independent lek locations. We estimated twice the amount of predicted nesting habitat within 3 km of leks compared to random locations in the PRB. Likewise we estimated 1.8 times more predicted nesting habitat within 10 km of leks compared to random locations. These results support predictions of the hotspot theory of lek placement. Local-scale habitat variables that cannot currently be mapped in a GIS strongly influence sage-grouse nest-site selection, but only within priority nesting habitats defined at the landscape scale. Our results indicate that habitat treatments for nesting sage-grouse applied in areas with an unsuitable landscape context are unlikely to achieve desired conservation results.     

伊朗八种跳小蜂及一新种记述（膜翅目：小蜂总科）

报道由伊朗设拉子大学农学院采集饲出的与林木害虫有关的７属８种寄生蜂,它们均属膜翅目小蜂总科、跳小蜂科,扬与林木介壳虫有关的Ａｎａｇｙｒｕｓ ｐｓｅｕｄｏｃｏｃｃｉ,Ｃｈｅｉｌｏｎｅｒｒｕｓ ｃｅｒｏｐｌａｓｉｔｓ,Ｄｕｓｍｅｔｉａ ｆａｓｃｉｐｅｎｎｉｓ,Ｈｏｍａｌｏｔｙｌｕｓ ｅｐｈｉｐｐｉｕｍ,与草蛉有关的Ｉｓｏｄｒｏｍｕｓ ａｔｒｉｖｅｎｔｒｉｓ,Ｉｓｏｄｒｍｕｓ ｃｏｌｌｉｍａｃｕｌａｔｕ     

冻融作用对土壤温室气体产生与排放的影响

土壤冻融交替是中、高纬度和高海拔地区常见的自然现象,土壤在冻融期间会经历一系列物理、化学和生物变化过程。有研究表明,冻融区土壤是温室气体的重要排放源,冻融期土壤温室气体的排放量在全年总排放量中占有重要的份额,尤其是N2O。随着全球气候变暖,部分地区的土壤环境将经受更广泛和频繁的冻融交替作用,这会导致土壤温室气体排放量增加,从而又进一步促进了气候变暖。本文重点概述了冻融作用对土壤温室气体产生与排放的影响及其主要影响机制,并简要提出了目前土壤冻融研究中的一些不足以及今后值得关注和深入研究的科学问题。     

The Effects of Spatial Scale on Trophic Interactions

Food chain models have dominated empirical studies of trophic interactions in the past decades, and have lead to important insights into the factors that control ecological communities. Despite the importance of food chain models in instigating ecological investigations, many empirical studies still show a strong deviation from the dynamics that food chain models predict. We present a theoretical framework that explains some of the discrepancies by showing that trophic interactions are likely to be strongly influenced by the spatial configuration of consumers and their resources. Differences in the spatial scale at which consumers and their resources function lead to uncoupling of the population dynamics of the interacting species, and may explain overexploitation and depletion of resource populations. We discuss how changed land use, likely the most prominent future stress on natural systems, may affect food web dynamics by interfering with the scale of interaction between consumers and their resource.     

Scale‐up of hydrophobin‐assisted recombinant protein production in tobacco BY‐2 suspension cells

Plant suspension cell cultures are emerging as an alternative to mammalian cells for production of complex recombinant proteins. Plant cell cultures provide low production cost, intrinsic safety and adherence to current regulations, but low yields and costly purification technology hinder their commercialization. Fungal hydrophobins have been utilized as fusion tags to improve yields and facilitate efficient low‐cost purification by surfactant‐based aqueous two‐phase separation (ATPS) in plant, fungal and insect cells. In this work, we report the utilization of hydrophobin fusion technology in tobacco bright yellow 2 (BY‐2) suspension cell platform and the establishment of pilot‐scale propagation and downstream processing including first‐step purification by ATPS. Green fluorescent protein‐hydrophobin fusion (GFP‐HFBI) induced the formation of protein bodies in tobacco suspension cells, thus encapsulating the fusion protein into discrete compartments. Cultivation of the BY‐2 suspension cells was scaled up in standard stirred tank bioreactors up to 600 L production volume, with no apparent change in growth kinetics. Subsequently, ATPS was applied to selectively capture the GFP‐HFBI product from crude cell lysate, resulting in threefold concentration, good purity and up to 60% recovery. The ATPS was scaled up to 20 L volume, without loss off efficiency. This study provides the first proof of concept for large‐scale hydrophobin‐assisted production of recombinant proteins in tobacco BY‐2 cell suspensions.     

Effects of land use on aquatic macrophyte diversity and water quality of ponds

1. Aquatic macrophyte diversity and water quality of 55 ponds in western Japan were related to land use and morphometric variables to identify the environmental factors that sustain biodiversity and the spatial extent at which these factors operate. 2. The relevant spatial extent for floating‐leaved macrophyte richness (500 m from pond edge) was larger than that for submerged macrophyte occurrence (10, 75 and 100 m), whereas emergent macrophyte richness was best explained at much larger extents (1000 m). Total macrophyte richness was explained at the extent of 500, 750 and 1000 m. The extents relevant for explaining the physicochemical condition of pond water (100 and 250 m) were similar to those for submerged and floating‐leaved macrophytes, suggesting that these two growth forms are more sensitive to water quality compared to emergent macrophytes. 3. Diversity of all three growth forms and that of total macrophytes collectively were inversely related to turbidity and nutrient concentration; among the three growth forms, submerged macrophytes were most affected by water quality. 4. Negative relationships were found between the proportion of urban area and the diversity of the three growth forms and that of total macrophytes and water quality. Species richness of emergent, floating‐leaved and total macrophytes decreased with depth and increased with surface area up to about 5000 m², above which it declined. 5. Urbanisation and enlargement of ponds were the two main factors that decreased aquatic macrophyte diversity in irrigation ponds. To alleviate the adverse effects of urban areas on aquatic macrophyte diversity, our results suggest that management efforts should focus on the creation of buffer zones within the relevant spatial extent from the pond edge.     

Pacific-wide contrast highlights resistance of reef calcifiers to ocean acidification

Ocean acidification (OA) and its associated decline in calcium carbonate saturation states is one of the major threats that tropical coral reefs face this century. Previous studies of the effect of OA on coral reef calcifiers have described a wide variety of outcomes for studies using comparable partial pressure of CO₂ (pCO₂) ranges, suggesting that key questions remain unresolved. One unresolved hypothesis posits that heterogeneity in the response of reef calcifiers to high pCO₂ is a result of regional-scale variation in the responses to OA. To test this hypothesis, we incubated two coral taxa (Pocillopora damicornis and massive Porites) and two calcified algae (Porolithon onkodes and Halimeda macroloba) under 400, 700 and 1000 μatm pCO₂ levels in experiments in Moorea (French Polynesia), Hawaii (USA) and Okinawa (Japan), where environmental conditions differ. Both corals and H. macroloba were insensitive to OA at all three locations, while the effects of OA on P. onkodes were location-specific. In Moorea and Hawaii, calcification of P. onkodes was depressed by high pCO₂, but for specimens in Okinawa, there was no effect of OA. Using a study of large geographical scale, we show that resistance to OA of some reef species is a constitutive character expressed across the Pacific.     

Spatial heterogeneity in genetic relatedness among house sparrows along an urban-rural gradient as revealed by individual-based analysis

Understanding factors that shape patterns of kinship in sedentary species is important for evolutionary ecologists as well as conservation biologists. Yet, how patterns of relatedness are hierarchically structured in space remains poorly known, even in common species. Here, we use information from 16 polymorphic microsatellite DNA markers to study how small-scale kinship structure varies among house sparrows (Passer domesticus) along an urban-rural gradient. Average levels of relatedness were higher among urban individuals than among individuals from rural areas, suggesting lower rates of dispersal in more built-up habitats. Comparison of observed levels of relatedness with simulated distributions of known kinship values showed that central urban individuals had the highest proportion of closely related conspecifics in their immediate neighbourhood. Spatial auto-correlograms supported this small-scale genetic structure and further indicated stronger effects of genetic drift and/or limited dispersal in urban populations. Results of this study underscore the importance of individual-level analyses as a complementary approach to traditional population-level analyses when studying genetic population structure over small spatial scales.