Surface controls on the characteristics of natural CO2 seeps: implications for engineered CO2 stores

CO₂ injected into rock formations for deep geological storage must not leak to surface, since this would be economically and environmentally unfavourable, and could present a human health hazard. In Italy natural CO₂ degassing to the surface via seeps is widespread, providing an insight into the various styles of subsurface ‘plumbing’ as well as surface expression of CO₂ fluids. Here we investigate surface controls on the distribution of CO₂ seep characteristics (type, flux and temperature) using a large geographical and historical data set. When the locations of documented seeps are compared to a synthetic statistically random data set, we find that the nature of the CO₂ seeps is most strongly governed by the flow properties of the outcropping rocks, and local topography. Where low‐permeability rocks outcrop, numerous dry seeps occur and have a range of fluxes. Aqueous fluid flow will be limited in these low‐permeability rocks, and so relative permeability effects may enable preferential CO₂ flow. CO₂ vents typically occur along faults in rocks that are located above the water table or are low permeability. Diffuse seeps develop where CO₂ (laterally supplied by these faults) emerges from the vadose zone and where CO₂ degassing from groundwater follows a different flow path due to flow differences for water and CO₂ gas. Bubbling water seeps (characterized by water bubbling with CO₂) arise where CO₂ supply enters the phreatic zone or an aquifer. CO₂‐rich springs often emerge where valleys erode into CO₂ aquifers, and these are typically high flux seeps. Seep type is known to influence human health risk at CO₂ seeps in Italy, as well as the topography surrounding the seep which affects the rate of gas dispersion by wind. Identifying the physical controls on potential seep locations and seep type above engineered CO₂ storage operations is therefore crucial to targeted site monitoring strategy and risk assessment. The surface geology and topography above a CO₂ store must therefore be characterized in order to design the most effective monitoring strategy.     

The emergence of agropastoralism: Accelerated ecocultural change on the Andean altiplano, ∼3540–3120 cal BP

In the fourth millennium BP, there were major environmental and cultural changes on the Andean altiplano of South America, but the chronology remains vague. A recent synthesis describes a slow, gradual transition from hunting and gathering to agropastoralism. This proposal is tested by refining the date of the onset of more humid and stable conditions, around 3550 cal BP, based on a Bayesian model of 26 dates from Lake Wiñaymarka and an updated calculation of the lacustrine offset. This is compared to Bayesian models of 191 dates from 20 archaeological sites, which incorporate a number of recently processed radiocarbon dates. A synthesis is presented of 15 full coverage surveys, a summed probability distribution, and a Bayesian model of the transition to ceramics, which together support a scenario of a very rapid demographic increase. Fourteen models from archaeological sites are cross-referenced in a composite model, which identifies a brief, altiplano-wide emergence of agropastoralism with starting and ending boundaries of 3540 and 3120 cal BP, respectively. This starting boundary correlates strongly with the onset of improving environmental conditions, indicating synchronous cultural and environmental change. The suite of accelerating cultural changes included a marked reduction in mobility, a demographic surge, increased subsistence diversity, the adoption of ceramics, farming and the integration of camelid herding into a remarkably resilient economic strategy still in use today. This is a highly relevant but yet to be used comparative case study for the variable tempos of ‘big histories’, and ecocultural interactions that generate rapid, emergent episodes of wide-spread and enduring cultural change.     

元代徽州路的军功家族

文章利用《汪氏渊源录》和《回岭汪氏宗谱》以及相关元代文集为主要参考资料,研究了元代徽州路的军功家族群体,尤其是其中的典型个案———婺源回岭汪氏。作者认为婺源回岭汪元龙、汪元圭兄弟在宋元易代之际,因为归附蒙元及“保障乡里”之功走上致身荣显的仕宦之路,他们不仅自身建立了可观的权势,而且有效地将之世代传承,以与元朝统治相始终,最终使婺源回岭汪氏家族成为“朱紫满庭”的“新安巨室”。在元代的徽州,类似的军功家族分布广泛,人数众多,深具影响。他们的出现,与元代统治者重视“根脚”的政治铨选原则紧密相关,与那些在蒙元征服战争中出现的“汉军世家”具有相似的来源和特点。     

考释胡适的两封书信

本文考证了胡适致任鸿隽、胡近仁两封信的写作时间,纠正了以往的误判。将信件的内容置于广阔的历史背景下加以考察,并与相关史料参考互证,不仅有助于考察信件的写作时间,且有助于理解信函的真实含义。     

明代年例银制度形成探论

明代年例银制度是经过长期演变逐渐形成的一项军事供给制度。宣德十年(1435)首先出现京运银,历经景泰、天顺时期,京运银两中有一笔银两开始向"岁例"发生制度性转变的趋势;成化、弘治之际,"常数"、"岁运"、"岁例"、"年例"、"年例银"等名称的出现是这笔京运银两制度化发展的结果,标志着明代年例银制度的初步形成;嘉靖十六年(1537)年例银一年一发的规定以及年例银会计预算制的出现,意味着明代年例银制度的完全确立。年例银制度的形成和确立,改变了明代国家的军事供给体制,是明代军事财政史上的一个重大变革。     

高句丽与汉魏晋及北族政权的朝贡关系

1—5世纪初,无论是统一王朝时期,还是王朝分裂、政权频繁更替时期,高句丽对中原王朝和北族政权都采取积极朝贡的姿态,朝贡活动呈现出单向、双向、多向的变化,先后向十多个王朝和政权进行朝贡。随着政治形势和朝贡对象的变化,高句丽朝贡活动的目的及其与朝贡对象的关系也有一定的变化。     

明初大运河南旺分水枢纽水工技术考

明朝初年,国脉皆仰东南,为解决南方粮财物的北运问题,宋礼和白英受命组织修建了大运河山东段南旺分水枢纽。该枢纽主要包括引汶济运、导泉补源、设立水柜和置闸节流四个组成部分。其中,引汶济运是工程之重点,包括戴村坝、小汶河、南旺分水以及配套工程等四个子系统。这些水利设施组成一个和谐的系统工程,保证了该段运河的水量稳定充足,从而实现了大运河500余年的正常通行。南旺分水枢纽代表了我国古代运河水工的最高科学技术成就,堪称世界水利史上的一大经典范例。     

不伦之伦:越继与降继——从族谱资料看明清徽州宗族承继的变体

宗祧承继是宗族研究的一个重要内容,学界对明清宗族继承问题研究已久,也取得了丰硕的成果,对于越继和降继,则甚少涉及。先贤们对徽州宗族社会有诸多理想性的描述,然而这些描述在很大程度上只是一种表象,现实的徽州社会要复杂得多,越继和降继就是其表现之一。探讨这两种承继方式,对于更好地解读宗祧承继和剖析明清时期徽州宗族社会的发展脉络,都有一定的积极意义。     

清末两级地方自治中的官治与自治模式

清末地方自治包括府厅州县和城镇乡地方自治两个层级,并建构了两个层级不同的官治与自治模式,即在城镇乡一级实行"以自治辅助官治",而府厅州县则实行"自治与官治合并"之制度。两种模式都借鉴了日本自治制度,但都有所不同。就清末城镇乡地方自治的运行来看,由于地方自治章程赋予官府监督自治之权,也由于自治团体为谋求地方利益,常常也会与官府对立,所以,官治与自治常常处于矛盾冲突之中。     

The Jaws Effect: How movie narratives are used to influence policy responses to shark bites in Western Australia

This article examines the way political actors use film narratives to influence policymaking following shark bites. To analyse these relationships I propose the concept of the Jaws Effect, where film-based historical analogies are used as a political device to frame real-life events in ways that make the events governable and prejudice certain policy options. Three elements of the Jaws Effect are reviewed including the intentionality of the shark, perception that these events are fatal and the belief that ‘the shark’ must be killed. These elements are applied to a case study of policy responses to shark bite episodes in Western Australia in 2000, 2003, 2011 and 2014. The reasons why this political device may not always work are also suggested.

本文研究了政治主体以什么方式使用电影叙事来影响鲨鱼咬人之后的政策制定。笔者提出“《大白鲨》效应”的概念,也就是以取自电影的历史类比为政治手段来言说现实生活中的事件,让事件根据言说者的需要,不利于某些政策选择。本文分析了《大白鲨》效应的三要素：鲨鱼的目的性;现实生活的事件性命攸关;鲨鱼必须被杀死。笔者将三要素用于研究2000、2003、2011和2014年西澳大利亚鲨鱼要人事件之后的政策反应。文章也探讨了为什么这种政治手法并不总能凑效。