基于深度学习街景影像解译和景感生态学的视域环境定量解读

城市物理环境带给居民丰富而生动的视觉意象,目前许多文献结果表明其宜人性与公共福祉以及健康状况息息相关。景感生态为探究城市物理环境与居民感知信息之间的联系提供了指导依据,通过人本尺度的定量手段解读城市环境中视觉、听觉和味觉等多维度感知信息。秉承景感生态学的基本原理,引入一种结合街景大数据和深度学习的城市环境量化手段,以北京市六环范围为例,将景感视率作为测度对人本视角下的城市环境展开定量解读。在全面把控多维景感要素的同时,旨在实现以人为本的城市物理环境优化设计,从而满足人们对生活品质提升的实际需求。实验结果显示:(1)从视觉感受的宏观表现来看,北京四环路范围内建成环境的"闭合感"较强,而对绿植的感知程度相对偏弱,因而需要开展存量环境设计并优化视域界面结构;(2)以景感视率作为特征值进行聚类得出3类主导空间(绿色空间、灰色空间和蓝色空间),可针对灰色空间着重部署垂直绿化资源,提高城市视觉绿化的可感知性,从而营造舒适宜人的绿色氛围、促进公众身心健康;(3)为景感生态学提供了基于大数据思维的数据集和定量方法补充。综上,以街景影像和景感生态视角对北京市中心城区的视域环境展开定量分析,采用了先进的深...     

基于绿视率的城市生态舒适度评价模型构建

城市生态系统服务指人类从城市生态系统中获取的利益,城市绿色空间是提供城市生态系统服务的主要载体。而城市化进程的加快对城市绿色空间的存量造成威胁,城市生态系统服务难以达到居民需求。传统的城市绿色空间评价指标集中于对城市绿地面积的评价,指标偏向整体性和二维化,忽视了三维绿量,也鲜少关注生态系统服务质量。基于以上背景提出了一个城市生态系统服务功能评价指标——城市生态舒适度,通过人体的主观感受对城市生态系统服务功能做出质量反馈,并结合灰色关联分析法构建了该指标的评价模型。通过样本的条件对比分析得出,当绿视率水平低于30%时,城市生态舒适度的主要影响因子为绿视率;当绿视率水平高于30%时,则是湿度、PM2.5浓度和风力等级。将评价模型的模拟结果与实测值进行对比验证,结果显示二者的变化趋势基本相同,表明评价模型科学有效。     

Microclimatic differences between and within canopy gaps in a temperate rainforest

The microclimate in the understorey and in two canopy gaps of different size (249 m² and 12.6 m²) within a temperate rainforest in northern New Zealand were characterised using net all-wave radiation (Q ^*), vapour pressure deficit (VPD), vertical air temperature gradient (VTG), and maximum and minimum air temperatures. Hemispherical fisheye photographs were used to define the exposure to the sky at each microclimate recording site both within and between gaps, and in the understorey. Under condiions of clear skies during the summer, with the sun close to its maximum altitude, the large gap centre had a mean daytime (0700–1700 hours)Q ^* of 452 W/m². This value was similar to that estimated for an open field nearby, but three times greater thanQ ^* at the centre of the small gap, and six times greater than in the understorey. The east and west sides of both gaps had higher values ofQ ^* than the north and south sides. BothQ ^* and mean daily maximum temperature were strongly correlated with the amount of sky exposure. VPD and VTG were higher in gaps than in the understorey, with maximum values for both variables occurring at the centre of the large gap.     

The uremic solute indoxyl sulfate acts as an antioxidant against superoxide anion radicals under normal-physiological conditions

The effect of the uremic solute indoxyl sulfate (IS) on scavenging superoxide anion radicals () generated from both the xanthine/xanthine oxidase (X/XO) system and activated neutrophils was investigated by electron paramagnetic resonance spectroscopy, combined with 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (EMPO). The findings show that the presence of normal-physiological serum concentrations of IS (0.1-10 μM) resulted in decreased formation of EMPO-superoxide adduct without affecting XO activity. Furthermore, IS showed scavenging activity against cell-derived generated from activated neutrophils. In addition, IS also eliminated hydroxyl radicals. These findings suggest that IS acts as a novel endogenous antioxidant under normal-physiological conditions.     

基于视觉指数的城市热环境效应——以徐州市为例

城市热环境与人居环境、居民健康以及城市可持续发展密切相关。本研究以绿视率(GVI)为基础,提出地上构筑物视率(CVI)和硬化地表视率(R&PVI)2种新的视觉指数,使用移动观测方法,在夏季末获取徐州市主城区、风景区、大学校园外部以及大学校园的城市热环境数据,并同步获取采样沿线的影像和坐标信息,分析以视觉指数所表示的城市构成对城市热环境的影响。结果表明: 在采样沿线上,研究区主城区平均气温(T_a,30.42 ℃)最高但相对湿度(RH,40.7%)最低,风景区的平均T_a(29.35 ℃)最低但RH(48.4%)最高;平均风冷温度(T_aW)在主城区最高(32.95 ℃),在风景区最低(31.93 ℃)。CVI由高至低依次为:主城区、大学校园、大学校园外部和风景区,GVI与CVI相反。CVI分别与T_a和T_aW呈极显著正相关,与RH呈极显著负相关;GVI分别与T_a和T_aW呈极显著负相关,与RH呈极显著正相关;R&PVI分别与T_a和T_aW呈显著和极显著正相关,与RH的相关性不显著。CVI和GVI对T_a的贡献显著,独立贡献率分别为10.4%和18.9%,联合贡献率分别为7.8%和11.3%;对RH而言,二者贡献同样显著,独立贡献率分别为37.5%和15.7%,联合贡献率分别为51.4%和30.2%;对T_aW而言,3种参数的贡献均达到显著水平,三者的独立贡献率和联合贡献率均低于对T_a的影响;3种参数对RH的影响高于对T_a和T_aW。研究结果可为优化城市热环境和缓解城市热岛效应提供思路,也对城市更新以及人居环境质量提升具有实践意义。     

THE SUBSTANCE VIEW: A CRITIQUE

According to the theory of intrinsic value and moral standing called the ‘substance view,’ what makes it prima facie seriously wrong to kill adult human beings, human infants, and even human fetuses is the possession of the essential property of the basic capacity for rational moral agency – a capacity for rational moral agency in root form and thereby not remotely exercisable. In this critique, I cover three distinct reductio charges directed at the substance view's conclusion that human fetuses have the same intrinsic value and moral standing as adult human beings. After giving consideration to defenders of the substance view's replies to these charges, I then critique each of them, ultimately concluding that none is successful. Of course, in order to understand all of these things – the reductio charges, defenders of the substance view's replies to them, and my criticisms of their replies – one must have a better understanding of the substance view (in particular, its understanding of rational moral agency) as well as its defense. Accordingly, I address the substance view's understanding of rational moral agency as well as present its defense.     

Multi-scale 3D Cryo-Correlative Microscopy for Vitrified Cells

1. Download : Download high-res image (197KB)
2. Download : Download full-size image

     

Shielded environments reduce stress in alien Asteraceae species during hot and dry summers along urban‐to‐rural gradients

Urban environments often host a greater abundance and diversity of alien plant species than rural areas. This is frequently linked to higher disturbance and propagule pressure, but could also be related to the additional establishment of species from warmer native ranges in cities, facilitated by the latter''s higher air temperatures and drier soils. A hitherto unresolved question is how stressful the urban environments become during climate extremes such as heatwaves and droughts. Do such episodes still favor alien plant species, or set them back? We used in situ measured phenotypic leaf and development trait responses of the six most widespread alien Asteraceae species from various native climates along Belgian urban‐to‐rural gradients, measured during two unusually warm and dry summers. Urbanization was characterized by three factors: the percentage of artificially sealed surfaces (urbanity, measured at three spatial scales from in situ to satellite‐based), the vegetation cover and the sky view factor (SVF, fraction of the hemisphere not blocked by buildings or vegetation). Across species, either from colder or warmer native climates, we found a predominant protective effect of shielded environments that block solar radiation (low SVF) along the entire urban‐to‐rural gradient. Such environments induced lower leaf anthocyanins and flavonols indices, indicating heat stress mitigation. Shielded environments also increased specific leaf area (SLA), a typical shade response. We found that vegetated areas had a secondary importance, increasing the chlorophyll content and decreasing the flavonols index, but these effects were not consistent across species. Finally, urbanity at the organism spatial scale decreased plant height, while broader‐scale urbanity had no significant influence. Our results suggest that sealed surfaces constrain alien Asteraceae during unusually warm and dry summers, while shielded environments protect them, possibly canceling out the lack of light. These findings shed new light on alien plant species success along urban‐to‐rural gradients in a changing climate.     

Comparison of polysialic acid production in Escherichia coli K1 during batch cultivation and fed-batch cultivation applying two different control strategies

The polysialic acid (PSA) production in Escherichia coli (E. coli) K1 was studied using three different cultivation strategies. A batch cultivation, a fed-batch cultivation at a constant specific growth rate of 0.25 h⁻¹ and a fed-batch cultivation at a constant glucose concentration of 50 mg l⁻¹ was performed. PSA formation kinetics under different cultivation strategies were analyzed based on the Monod growth model and the Luedeking-Piret equation. The results revealed that PSA formation in E. coli K1 was completely growth associated, the highest specific PSA formation rate (0.0489 g g⁻¹ h⁻¹) was obtained in the batch cultivation. However, comparing biomass and PSA yields on the glucose consumed, both fed-batch cultivations provided higher yields than that of the batch cultivation and acetate formation was prevented. Moreover, PSA yield on glucose was also correlated to the specific growth rate of the cells. The optimal specific growth rate for PSA production was 0.32 h⁻¹ obtained in the fed-batch cultivation at a constant glucose concentration of 50 mg l⁻¹, with highest conversion efficiency of 43 mg g⁻¹.