An Ecological Redoubt: Assisting the Migration of Sensitive Flora in the Central Swiss Alps

Switzerland’s alpine ecologies are uniquely affected by climate change. Many of the country’s plant species are migrating higher in altitude due to rising annual mean temperature with extensive habitat loss expected in as early as 2050. Given the compounded effects of the growing tourism economy and the expanding presence of aggressive pioneer plant species, regionally significant alpine meadows have been displaced before their sensitive and rare plant communities can adapt. This impending loss of biodiversity is quickly becoming a national ecological redoubt. Situated at the crossroads of the Oberalp, the St. Gotthard, and the Furka passes, the town of Andermatt lies at the eastern end of the Urseren Valley, a floristically diverse region of Central Switzerland. Abandoned military bunkers and fortresses (Fort Stöckli and Artillery Works Gütsch) overlook Andermatt as relics of the Swiss National Redoubt defence plan. This project investigates how specific military infrastructure integrated into the landscape can be repurposed into living archives for research, preservation, and propagation of alpine plant communities. Can this design strategy combining active and passive interventions mitigate anthropocentric pressures on these alpine ecologies while providing a new purpose to outmoded military infrastructure? Will a strategically managed ecological retreat preserve Swiss identity beyond the non-human?     

Efficacy of increasing discharge to reduce tow-mediated fish passage across an electric dispersal barrier system in a confined channel

The Electric Dispersal Barrier System (EDBS) in the Chicago Sanitary and Ship Canal (CSSC) was built to limit the interbasin transfer of aquatic invasive species between the Mississippi River Basin and the Great Lakes Basin. Commercial barge traffic, or tows, moving downstream through the EDBS can facilitate the upstream passage of small fish through the barrier by reducing the voltage gradient of the barrier and causing localized upstream return currents. This study tested whether it is possible to prevent upstream passage of small fish across the barrier by preventing upstream return currents. Measurements of water velocity, voltage gradient, and tow speed, as well as sonar-based observations of resident fish, were made as a tow transited the EDBS moving downstream. The results indicate that upstream return currents can be prevented for typical flow conditions in the CSSC (ambient velocity = 0.15 to 0.23 m/s) when tow speeds are <0.46 m/s. Similarly, increasing the ambient velocity above typical values can prevent upstream return currents for faster tow speeds and larger tows. Additionally, preventing upstream return currents at the EDBS may reduce, but does not prevent, tow-mediated upstream fish passages because tows also cause a temporary reduction in the streamwise voltage gradient at the EDBS. These results have implications for the management of invasive bigheaded carps in the Illinois Waterway.     

Recent advances and future challenges in the use of nanoparticles for the dispersal of infectious biofilms

Increasing occurrence of intrinsically antimicrobial-resistant,human pathogens and the protective biofilm-mode in which they grow,dictates a need for the alternative control of infectious biofilms.Biofilm bacteria utilize dispersal mechanisms to detach parts of a biofilm as part of the biofilm life-cycle during times of nutrient scarcity or overpopulation.We here identify recent advances and future challenges in the development of dispersants as a new infection-control strategy.Deoxyribonuclease(DNase)and other extracellular enzymes can disrupt the extracellular matrix of a biofilm to cause dispersal.Also,a variety of small molecules,reactive oxygen species,nitric oxide releasing compounds,peptides and molecules regulating signaling pathways in biofilms have been described as dispersants.On their own,dispersants do not inhibit bacterial growth or kill bacterial pathogens.Both natural,as well as artificial dispersants,are unstable and hydrophobic which necessitate their encapsulation in smart nanocarriers,like pH-responsive micelles,liposomes or hydrogels.Depending on their composition,nanoparticles can also possess intrinsic dispersant properties.Bacteria dispersed from an infectious biofilm end up in the blood circulation where they are cleared by host immune cells.However,this sudden increase in bacte-rial concentration can also cause sepsis.Simultaneous antibiotic loading of nanoparticles with dispersant properties or combined administration of dispersants and antibiotics can counter this threat.Importantly,biofilm remaining after dispersant administration appears more susceptible to existing antibiotics.Being part of the natural biofilm life-cycle,no signs of"dispersant-resistance"have been observed.Dispersants are therewith promising for the control of infectious biofilms.     

Avian movement across abrupt ecological edges: Differential responses to housing density in an urban matrix

The movements of birds across habitat edges were investigated at the interface between remnant bushland and two densities of suburban housing. Behavioural responses to edges adjoining the two densities of housing matrix differed significantly among feeding guilds. Omnivores and nectarivores were significantly more likely than insectivores to penetrate edges adjoining high-density housing. Analysis of individual species revealed several consistent trends. Nectarivorous species appeared more likely to cross at edges of high-density housing, while insectivores were more likely to cross at edges of low-density housing. Regression models suggest these trends may be influenced by characteristics within the matrix, principally the proportion of housing and variables associated with shrub and canopy vegetation. These trends corresponded well with the known distribution of the guilds in remnant vegetation of the suburban landscape. Importantly, by crossing at these habitat edges, many species demonstrate that with appropriate management of the housing matrix they have the potential for dispersal necessary for the maintenance of meta-populations.     

对“脏弹”恐怖袭击初始响应人员防护干预行动的一些讨论

相比于核设施事故,"脏弹"恐怖袭击在发生地点、放射性物质释放方式和辐射影响范围等方面都有所不同,后者具有突发性、可能发生在人口集中的市区、现场不确定因素多等特点。文中分析了初始响应人员的防护以及在隐蔽、临时撤离等公众防护干预行动应用中需要考虑的一些问题。重点对营救阶段初始响应人员到达袭击现场后,应急工作区初始大小的确定、内外警戒区的划分和公众防护措施的合理应用等方面进行了讨论,并提出了相应的建议。     

察尔汗盐湖钾卤水动态二维模型的算法研究

青海察尔汗盐湖是我国第一大规模开发的钾盐基地,该文主要是对察尔汗盐湖首采区关于提取卤水的二维动态模型进行求解研究——将混合拉普拉斯变换有限单元法引入到求解首采区卤水动态二维模型中溶质运移的问题中。在求解对流占优的地下水溶质运移问题时,常规数值方法会产生数值扩散和过量现象,而此方法能够有限地消除数值扩散和过量的现象,还具有一步到位、局部求解的优点。还将此方法应用到具有空间一阶导数项的对流弥散方程,以检验算法的数值有效性和求解溶质运移模型的能力。     

The development of epigeic fauna in new hedges — a comparison of spatial and temporal trends

The colonisation of a linear sequence of nine young hedge plantations (each 400 m²) within an intensely cultivated landscape about 30 km to the west of Bonn has been studied to compare spatial and temporal distribution patterns of epigeic arthropods in order to consider differences obtained concerning an assessment of colonisation characteristics and dispersal trends. The investigation was started in 1982, the year in which the new hedges were planted and continued until 1991. Pitfall traps—usually six as a standard set—were installed in young hedges and in old wooded habitats of an adjacent semi-natural habitat complex, as well as in surrounding arable fields and in meadow strips connecting the hedge plantations. But only in 1990 nearly all the habitats were sampled at the same time. Between 1982 and 1989 catches were continuously performed only in two habitats, since 1986 in four young habitats.Results on species of the taxonomical groups of Carabidae, Opilionida and Araneida show that the analysis of spatial only or temporal only patterns can lead to different interpretations and sometimes wrong conclusions about the colonisation of new hedge habitats. Both types of data, comprehensive spatial and long-term temporal, are complementary and a combination of both is recommended for properly assessing dispersal of species and other dynamic processes in the landscape. As far as the colonisation of new hedges is concerned it is shown that despite high temporal dynamics in species abundances and remarkable differences between the three taxa considered, the development towards a typical hedge fauna progresses very slowly. Small, 9-year-old hedges do not function well as stepping stones for the dispersal of epigeic forest and forest-edge arthropods, and only a small corridor effect could be established for the linear plantation strip. Remarkable differences in colonisation trends between beetle and spider species of similar ecological preferences are discussed.     

纳米Ag-Cu-In-Sn合金粉体的分散稳定性研究

通过等离子体蒸发凝聚法制备纳米Ag-Cu—In—Sn合金粉，初步研究了聚乙烯吡略烷酮K-30（PVP）和十六烷基三甲基溴化铵（CTAB）及其分散工艺对合金粉体分散性能的影响。研究结果表明：随着超声时间的增加，吸光率增大，分散性能变好；与CTAB相比PVP的分散效果更好，其最佳分散浓度为1．8g／L。     

Evaluation of synthetic hydrocarbons for mark-recapture studies on the red milkweed beetle

This study evaluates the potential for using blends of synthetic hydrocarbons in mark–recapture studies of insects. To test the durability of hydrocarbons, we applied a blend of five straight-chain hydrocarbons (C₂₄, C₂₅, C₂₆, C₂₈, C₃₀) to detached elytra of the red milkweed beetle, Tetraopes tetrophthalmus (Forster) (Coleoptera: Cerambycidae), mounted the elytra on pins, and placed them in an exposed location outdoors. The amount of hydrocarbons on the elytra did not change over time, even after two months of exposure to sun and rain. Synthetic hydrocarbons applied to the elytra of living beetles did not significantly influence their longevity or mating success in a laboratory study, and the amounts of hydrocarbons did not change with age. The invariability of hydrocarbon ratios over time suggests that blends could provide a nearly infinite variety of ratios to mark individual insects uniquely and indelibly with a hydrocarbon fingerprint. This technique offers a convenient, safe, and durable means of individually marking insects and may find application in field studies of larger bodied insects that are long-lived and sedentary.     

From the Cold War to the warmed globe: planning,design-policy entrepreneurism,and the crises of nuclear weapons and climate change

Faced with two existential threats – nuclear war and climate change – planners have responded by proposing sweeping reforms for city-regions, often deploying the newfound rationales to re-package earlier ideas about ‘the good city’. This paper analyses how mid-twentieth-century planning discourses regarding Cold War urban dispersal in the USA might help us understand contemporary conversations about urban climate change adaptation. We apply Kingdon's Multiple Streams Analysis and his concept of policy entrepreneurs to show how planners frame problems and shape policy agendas. We propose a subtype of ‘design-policy entrepreneurs’ who use the spatial and visual tools of planning and design to advocate for preferred policies. By analysing the rhetoric and visual representations made by planners and designers from 1945 to 1965, we examine how they repurposed long-standing ideas about urban deconcentration into ‘dispersal for defence’ proposals. Such proposals for dispersing urban settlements into separated and ‘self-contained’ units received a dysfunctional partial acceptance: housing and transportation legislation embraced the dispersal part but resisted the complementary elements aimed at limiting damages from nuclear attack by concentrating development into distinct nodes. We conclude by asking how the perils of such partial policy-making success might play out on the terrain of climate change adaptation.