Invasive cordgrass (Spartina spp.) in south‐eastern Australia induces island formation,salt marsh development,and carbon storage

Invasive vegetation species can lead to major changes in the geomorphology of coastal systems. Within temperate estuaries in the southern hemisphere, especially Australia and New Zealand, the cordgrass Spartina spp. has become established. These species are highly invasive, and their prolific growth leads to the development of supratidal environments in formerly intertidal and subtidal environments. Here, we quantified the impact of Spartina invasion on the geomorphology and sequestration capacity of carbon in the sediments of Anderson Inlet, Victoria, Australia. Spartina was first introduced to the area in the 1930s to aid in land reclamation and control coastal erosion associated with coastal development. We found that Spartina now dominates the intertidal areas of the Inlet and promotes accretion (18 mm/year) causing the formation of over 108 ha of supratidal islands over the past 100 years. These newly formed islands are calculated to potentially contain over 5.5 million tonnes of CO₂ equivalent carbon. Future management of the inlet and other Spartina‐dominated environments within Australian presents a dilemma for resource managers; on the one hand, Spartina is highly invasive and can outcompete native tidal marshes, thereby warranting its eradication, but on the other hand it is likely more resilient to rising sea levels and has the potential for carbon sequestration. Whether or not the potential advantages outweigh the significant habitat change that is anticipated, any management strategies will likely require additional research into costs and benefits of all ecosystem services provided by Spartina including in relation to nutrient cycling, shoreline stabilisation, and biodiversity as well as in response to the longevity of carbon found within the sediments.     

MIGRATION AND NARRATION: HOW EUROPEAN HISTORIANS IN THE NINETEENTH AND EARLY TWENTIETH CENTURIES TOLD THE HISTORY OF HUMAN MASS MIGRATIONS OR VÖLKERWANDERUNGEN

Historians’ interest in the history of human migrations is not limited to recent years. Migrations had already figured as explanatory factors in connection with cultural and historical change in the work of classical and ancient studies scholars of the late nineteenth and early twentieth centuries. In the writings of these scholars, migrations acted as historical landmarks or epochal thresholds and played a key role in the construction of geo-historical areas. This model has been called “migrationism” and cannot be explained simply on the basis of the history of individual disciplines, but must be seen in its complex interaction with scientific and historical contexts. However, “migrationism” does not relate to fixed political and scientific positions or movements. For this reason, it cannot be explained adequately by using a historically or ideologically based approach. Relying on narratological approaches, this article examines migration narratives that historians of this period used to explain the rise and fall of ancient civilizations. Referring to contemporary historiographical representations of the ancient Near East, it distinguishes three main narratives that are still common today: narratives of foundation, narratives of destruction, and narratives of mixtures. In this sense, analyzing older migration narratives helps us to sharpen the critical view on the genealogy of our own views on the history—and present—of human migrations.     

Capillary Active Interior Insulation Systems for Wall Retrofitting: A More Nuanced Story

To thermally upgrade exterior masonry walls, interior insulation is often the only possible retrofitting technique, especially when dealing with historic buildings. Unfortunately, it is also the riskiest post-insulation technique, as frost damage, interstitial condensation, and other damage patterns might be induced. To diminish those risks, nowadays so-called capillary active interior insulation systems are often promoted. These systems aim a minimal reduction of the inward drying potential, while interstitial condensation is buffered.

Currently, several capillary active systems are on sale. These different types have, however, widely varying properties. In this article, a closer look at the hygrothermal properties and the working principle of a number of “capillary active” interior insulation systems is made. The spread in capillary absorption coefficients and the vapor diffusion resistances of the different systems is discussed and their influence is illustrated. Based on all this, a more nuanced view on capillary active insulation systems is pursued.

Abbreviations: AC: aerated concrete; CaSi: calcium silicate; GM: glue mortar; GB: gypsum board; HAMFEM: Heat Air and Moisture Finite Element Method; MW: mineral wool; PE: polyethylene; PIR: polyisocyanurate; PUR: polyurethane; VIP: vacuum insulation panel; WFB: wood fiber board; XPS: extruded polystyrene; sd_dry: dry vapor diffusion resistance factor; µ_dry: dry vapor diffusion resistance     

水环境变迁与徐州城市兴衰研究

水对城市发展至关重要,严重水灾可能会酿成"城毁人亡"的悲局。历史上徐州饱受水灾之苦,特别是黄河决口南徙打乱了原本水系,使得境内水灾频仍,经济和社会发展受阻,在很大程度上导致了城市的衰落。但另一方面,沂、沭、泗以及故黄河所带来的便利灌溉条件则促进了境内古代农业生产;而运河开凿又使徐州处于全国重要的水运枢纽位置,因此带来商贸繁荣、工业发展、人口集聚和城市兴盛。本文在对历史上徐州水系变迁、尤其是水灾频发及其产生原因作出深入分析的基础上,着重探讨了境内水环境变化对徐州城市兴衰主要方面的影响。研究表明:①黄河对徐州水系变迁和城市兴衰影响巨大,直接时间持续近700年;②良好的水环境对历史上徐州境内工农业生产、商品贸易和城市建设起到了极大的推动作用,城市的繁荣兴旺与农田水利的风调雨顺、水上运输的川流不息往往处于同一个时期;③建国后徐州境内水系得到逐步治理与恢复,特别是20世纪80年代中期京杭运河(徐州段)实现全年通航后,其城市发展的水环境得到极大改善,为打造山水生态园林城市提供了良好条件。     

沛谯英雄的两次崛起与汉王朝的兴亡

沛谯又称谯沛,汉魏二祖和自己的功臣集团两次从这一地区崛起,于400年间,一首一尾,书写了汉王朝从建国到终结的历史。沛谯地方位于黄淮海平原。这里自战国晚期起,已经拥有富足的经济基础和充备的文化资源。楚文化的长期积累,在这里形成了新的重心。汉初梁国的文化优势,也对这里的人才形势有所影响。刘邦集团和曹操集团虽然都崛起于沛谯,而前者多布衣、白徒、亡命无赖,往往只是以个人身份追随刘邦,后者则以诸夏侯曹为代表,以宗族势力参与政治军事争搏,且其中颇有豪富。这一情形与东汉豪族势力的兴起有关。     

典型石窟砂岩的毛细吸水与变形响应特征

针对云冈石窟、乐山大佛和大足石刻,选择当地新鲜砂岩开展蒸馏水一维毛细上升试验,获取吸水质量和浸润前锋演变趋势,同时利用三向应变花测定试样不同高度处表面局部微应变的发展规律,并结合微观结构特征对宏观性质进行分析。研究结果表明:整个毛细吸水过程可划分为3个阶段,吸水率以及毛细高度随时间变化最快和最慢的分别是乐山砂岩和大足砂岩;云冈、大足和乐山砂岩局部微应变的最终值依次增加,且存在数量级上的差异,其变化趋势与浸润前锋运移密切相关,竖直和斜45°应变表现为先收缩后膨胀;砂岩毛细吸水和水化变形能力的关键影响因素分别是孔径分布和黏土矿物成分,其与文物真实产生的粉化、崩解、开裂和片状剥落等表面风化病害的形成密切相关。研究成果可为毛细水相关的劣化机理揭示提供丰富的参考数据,并向类似文物的病害评估与科学保护提供可靠的理论依据。     

崔述的历史盛衰论

崔述穷一生精力 ,考辨古史 ,成就很大 ,对后世史学也有很大影响。但崔氏在考史中又论史、论历史盛衰 ,有很多精审见解 ,崔述很少用性理天道论历史变化 ,注意对历史过程考察 ;他对历史“势”的分析值得总结 ,注重从人事作用上对历史盛衰变动原因进行考察 ,也体现出对民众的同情。崔述的考史能在求真基础上求理 ,显示出特色来。     

塔里木河下游绿色走廊的兴衰与保护

在历史上 ,塔里木河下游改道主要有 5次 ,每次改道都引起下游地区生态环境的剧变 ,绿色走廊的衰退 ,给我们留下了宝贵的经验教训。塔里木河下游的绿色走廊能否得到保护 ,关键是看有无保护它的水量。现在南疆之水量完全可以维护南疆的生态 ,塔里木河下游之水量完全可以维护塔里木河下游的生态。目前南疆严重缺水、塔里木河下游严重缺水 ,根本原因不是水量不足 ,而是没有管好用好现有水源。文章提出了保护塔里木河下游绿色走廊的 1 8项措施     

The coastal landslides of Shetland

Little is known of hard-rock coastal landsliding in Scotland. We identify 128 individual coastal landslides or landslide complexes >50 m wide along the coasts of Shetland. Most are apparently translational slides characterized by headscarps, displaced blocks and/or debris runout, but 13 deep-seated failures with tension cracks up to 200 m inland from cliff crests were also identified. Thirty-one sites exhibit evidence of at least localized recent activity. Landslide distribution is primarily determined by the distribution of coastal cliffs >30 m high, and they are preferentially developed on metasedimentary rocks. Analysis of 16 landslides on Fetlar (NE Shetland) indicates that most are translational dip-slip failures; 3 represent deep-seated failures and several exhibit active frontal erosion attributable to basal sapping by storm waves. As these landslides terminate in shallow water, failure was probably initiated when rising sea level resulted in footslope erosion and upslope propagation of instability, causing downslope displacement of landslide blocks on upper slopes. ¹⁰Be exposure dating of two headscarps yielded ages of 4.8?±?0.2 ka and 4.4?±?0.2 ka, consistent with the onset of footslope erosion as sea level rose. Our results suggest that landslides have played a hitherto undocumented but important role in retreat of cliffed coastlines in Scotland.     

A Further Proposal for the Hull Lines of the Madrague de Giens Ship (c.70 BC)

A review of studies carried out since 1978 on the Madrague de Giens ship remains have enabled a reassessment of the vessel's shell‐first construction process. Hypotheses concerning moulding criteria are developed, with the profile (sheer plan), main cross section (body plan), and active sections and reference planks used to mould the hulll proposed and evaluated. These are compared to the Marsala (3rd century BC), and Yass?ada 2 (4th century AD) ships, which have similar wine‐glass‐shaped bottoms. Some aspects of these moulding criteria appear common to those used in the Mediterranean during the Middle Ages and the Renaissance.