The Puzzle of the Diffusion of Central-Bank Independence Reforms: Insights from an Agent-Based Simulation

The emergence of an ever‐widening sphere of global public policy is a new reality in a world characterized by the blurring of boundaries between the national and the global; by flows of ideas, people, and commodities; and by new global risks and opportunities. In this context, this article explores the empirical puzzle of the sudden outbreak of reforms leading to central‐bank independence. How can we best understand the outbreak of reforms in the 1990s? It is suggested here that the reforms were diffused in a contagious and uncoordinated manner in a global policy process that may best be captured by Kingdon's policy stream model. We develop an agent‐based model to evaluate the effects of three little‐explored aspects of the diffusion process. These are (i) the likelihood of the outbreak of reform, (ii) the rate of adoption of the reform, and (iii) the time to outbreak. We find that the likelihood of outbreak depends on the saliency of a problem, in conjunction with the length of time that a problem has been on the public agenda. We also find that an increase in the size of the environment surveyed before a decision is made increases the rate of adoption but also the time to outbreak. The more global the information available for agents, the longer is the time to outbreak, but outbreaks unfold much faster.     

The changing shape of island epidemics: historical trends in Icelandic infectious disease waves, 1902–1988

Iceland's centuries-long history of epidemics with its unusually complete disease records has attracted study from several disciplines. But detailed spatial data of particular interest to historical geographers date only from 1895 and were consistently maintained for about a century thereafter. Within this period, this paper concentrates on morbidity records of reported cases of infectious diseases for an 87-year window which was open between 1902 and 1988. In this time slice, spatially detailed data for seven demographically important infectious diseases allow the geography of 131 discrete epidemic waves with a recorded total of 529,000 cases to be tracked. Changes in the behaviour of the seven diseases over the period are analyzed and related to both epidemiological theory and to the changing historical geography of the island. The paper complements earlier Icelandic work by the authors on the historical geography of single diseases (measles, influenza and poliomyelitis) by extending the range of diseases, and by considering their common spatial behaviour and their interrelationships.     

天主教在广西沿北部湾地区传播、扩散过程中的海岛效应和点轴模式

本文以天主教在广西沿北部湾地区的传播、扩散为例,试图揭示其传播、扩散的地理学规律。研究表明,天主教在环北部湾地区的传播分布基本上符合清末年间传教士先从沿海港口登陆,渐次沿交通干道向内陆地区扩散的点轴扩散模式。需要强调的是,涠洲岛以其地理上的闭合性特征在天主教进入广西初期扮演了弹跳板和插转台的角色,进而直接影响到广西沿北部湾地区天主教分布格局的形成。     

Molecular transport of methane, ethane and nitrogen and the influence of diffusion on the chemical and isotopic composition of natural gas accumulations

Laboratory experiments have been performed to determine diffusion coefficients of natural gas components (methane, ethane and nitrogen) and isotope fractionation effects under simulated in situ pressure (up to 45 MPa effective stress) and temperature conditions (50–200°C) in water‐saturated pelitic and coarse‐grained rocks. Effective diffusion coefficients of molecular nitrogen (0.39 × 10^?11 to 21.6 × 10^?11 m² sec^?1 at 90°C) are higher than those for methane (0.18 × 10^?11 to 18.2 × 10^?11 m² sec^?1 at 90°C). Diffusive flux rates expressed in mass units are generally higher for N₂ than for CH₄. Both methane and (to a lesser extent) nitrogen diffusion coefficients decrease with increasing total organic carbon (TOC) content of the rock samples because of sorption processes on the organic matter. This effect decreases with increasing temperature. Effective diffusion coefficients increase upon a temperature increase from 50 to 200°C by a factor of four. Effective diffusion coefficients and steady‐state diffusive flux decrease with effective stress. Stationary diffusive fluxes drop by 50–70% for methane and 45–62% for nitrogen while effective diffusion coefficients are reduced by 38% (CH₄) and 32–48% (N₂), respectively. Isotope fractionation coefficients of diffusive transport are higher for methane (?1.56 and ?2.77‰) than for ethane (?0.84 and ?1.62‰). Application of the experimental results to geological systems show that diffusive transport has only a low transport efficiency. Significant depletion of natural gas reservoirs by molecular diffusion is only expected in cases of very poor caprock qualities (in terms of thickness and/or porosity) and over extended periods of geological time. Under these circumstances, the chemical and isotopic composition of a gas reservoir will change and maturity estimates based on these parameters may be deceptive. To account for these potential effects, nomograms have been developed to estimate diffusive losses and apply maturity corrections.     

Whence nationalism?

ABSTRACT. There is widespread agreement that nationalism emerged in the historical fountainheads of modernity, and was subsequently diffused outwards. Contrary to that, there is a long standing view that nationalism precedes modernity even in the broadly accepted cradles of both modernity and nationalism, such as England or France, neither of which was modern when it engendered nationalism. Besides, some emergent nationalisms ran concurrent with their English or French counterparts, with little evidence of having been spawned by diffusion. Such early or protonationalisms often sprang from resistance to foreign conquest, putting in doubt the invention‐diffusion hypothesis. I am therefore suggesting that nationalism has not emerged in few societies, but in many, and that it was engendered by social interactions, not by a particular social formation. While nationalism emerges within society, its genesis occurs in‐between social groups and societies, making it a product of their interactions. That makes it u‐topic, its cradles socially diverse, and its conception interactional, not gestational.     

New insights from reactive transport modelling: the formation of the sericitic vein envelopes during early hydrothermal alteration at Butte, Montana

A reactive transport computer code has been employed to model hydrothermal alteration of a granitoid rock bordering a discrete vein channel. The model suggests that the grey sericitic and sericitic with remnant biotite alteration envelopes at the porphyry copper deposit at Butte, Montana, can be formed by a reducing, low pH, and low salinity fluid under constant temperature and pressure conditions of approximately 400 °C and less than 100 MPa during a time span of approximately 100 years or less. Hydrothermal alteration has little effect on the porosity of the host rock (Butte Quartz Monzonite), and the diffusivity of the aqueous species also changes little. A sequence of mineral reaction fronts characterizes the alteration envelopes. The biotite dissolution front occurs closest to the vein channel and marks the transition from the grey sericitic to sericitic with remnant biotite envelope. The plagioclase dissolution front occurs farthest into the matrix and marks the edge of relatively fresh Butte Quartz Monzonite. From the properties of the quasi‐stationary state approximation ( Lichtner 1988 ; Lichtner 1991 ), it follows that once the sequence of reaction fronts is fully established, their relative locations remain constant and the widths of the reaction zones increase with the square root of time.     

Moves and Countermoves: Countermovement Diffusion of State Constitutional Amendments

Policy diffusion literature generally studies the adoption of similar policies across jurisdictions, but often overlooks how opposing policies or legal constraints may influence the enactment of rigid state constitutional amendments. The current study models the spread of state constitutional amendments designed to prevent future policy change. Using conditional event history analysis on all states from 1999 to 2011 the empirical models analyze the spread of same‐sex marriage prohibitive amendments across the United States. Findings suggest that the nearby adoption of opposing policies encourage state legislatures to introduce prohibitive amendments. The regional diffusion effect suggests that policymakers “protect” their jurisdiction from nearby diffusion forces or seek electoral gains by symbolic protection by committing an already existing policy into the rigid state constitutional framework. Regional policy diffusion may, therefore, be explained by a countermovement mechanism unique to the state constitutional amendment process. This protective strategy among state legislatures and citizens may explain why many policy areas are frequently codified in state constitutions.     

分析SARS:在我国的地理扩散和地理障碍

SARS疫情在我国的迅速传播已经对我国的社会和经济生活造成了重大的影响,也为我们观察和分析地理扩散提供了难得的机会。SARS的扩散显然是一种地理过程,这个过程的第一个特征是以等级扩散为发展方式的,第二个特征是必然在扩散中遇到障碍。第一个特征的存在使疫情在一段时间里在我国得以迅速的蔓延,但是当采取各种医疗、隔离和防护措施后,SARS的扩散在出现障碍的条件下受到抑制。文章描述了疫情扩散的方式,在我国形成的地理格局(以广东和北京为源地),认为这个地理格局的形成与我国流动人口的分布、人口流动的条件有关。同时指出,在疫情扩散的地理格局中,在中心城市形成的高度集中是一种令人担忧的现象。因为这样的集中已经对这些中心城市的包括"医疗中心"在内的行政、经济、交通等核心地的功能产生严重影响。为此,文章注意到我国一些没有发现疫情的地区的地理条件,认为存在着如地理距离(距离衰减)、地理环境、产业特征等地理障碍。通过对这些障碍的分析,文章最后提出了防治疫情及其继续扩散的措施。     

Johann Gaspar Spurzheim: The St. Paul of phrenology

ABSTRACT

Franz Joseph Gall’s wayward discipline Johann Gaspar Spurzheim greatly modified Gall’s original system and introduced it to the English-speaking world. Through an active program of itinerant lecturing, publishing and converting disciplines, Spurzheim made phrenology. He also developed a philosophy of following the laws of nature that was adopted and further promoted by his disciple, George Combe. Combe’s book The Constitution of Man (1828) became one of the best-selling works of its genre in the nineteenth century. Thus Spurzheim, never particularly original, exercised an enormous influence on nineteenth-century culture.     

矿化溶液浸泡-气体扩散法加固骨质文物

本研究探讨了以钙源、磷酸盐源、胶原蛋白矿化溶液浸泡—气体扩散多循环法加固古代骨骼材料的工艺方法，并利用超景深显微镜、傅里叶转换红外光谱(FT-IR)、X射线衍射仪、扫描电镜和色度分析法、抗压强度试验等方法研究了保护效果。结果表明，利用该工艺处理后的生物磷灰石骨骼具有加固材料成分和骨质本体一致，原位合成且深入到骨质内部等特点，克服了有机聚合物及其他矿物材料简单物理充填的一些弊端，且处理过程简单、效率高、外观改变小，能满足对脆弱骨质文物、人骨及其他动物骨骼的加固保护需求。