Semi-empirical models of the neutral atmosphere based on turbopause height and exospheric temperature variations

Based on mass spectrometer observations of the satellites Ogo 6 and Esro 4 the long periodic density variations of He, O, N₂ and Ar are interpreted to be a result of combined variations of the exospheric temperature and the turbopause height. Only these two parameters are used in the models. Thus in comparison with previous models the number of parameters needed is significantly reduced. This simplification does not diminish the accuracy of the analytic representation of the observations and provides new physical insight into the processes which govern the dynamic behaviour of the neutral thermosphere. The annual variation of the turbopause height is found to cover the height range between 90 and 115 km and is approximately equal for both the Ogo 6 and the Esro 4 data.     

GIS and the application of a model of pollen deposition and dispersal: a new approach to testing landscape hypotheses using the POLLANDCAL models

The recent advances in computer-based modelling of pollen dispersal and deposition through the POLLANDCAL (POLlen-LANDscape CALibration) network have enabled landscape simulations to be constructed and tested, both to validate the theoretical models, and to validate modelled landscapes using empirical data. This paper presents the first attempt to develop simulations based on real landscapes, by placing distinct vegetation communities using reclassified digital elevation models (combined slope and altitude data). The approach is tested by modelling a palynological signature for the expansion of mixed agriculture into an upland margin, and the results for 49 simulated pollen deposition sites, across an altitudinal range for a series of landscape scenarios, is compared with existing empirical data. The broad trends within the two data sets are in general accordance, and variation between them is attributed to local variation in vegetation heterogeneity. The results show that the POLLANDCAL models offer a new and exciting method by which sub-fossil pollen assemblages can be examined, theoretical models of landscape use tested, and will offer a significant tool in the interpretation of environmental data in archaeology, in particular when combined with GIS-based models of the physical environment.     

High resolution turbulence observations in the middle and lower atmosphere by the MU radar with fast beam steerability: preliminary results

Refractive index fluctuations or turbulence in the mesosphere, stratosphere and troposphere are observed with the aid of the fast beam steerability of the MU (middle and upper atmosphere) radar which operates at 46.5 MHz with 1 MW peak radiation power and 8330 m² antenna aperture. Morphology of the mesospheric and stratospheric turbulence is studied by making use of the high altitude and time resolutions. Sixteen beam observations based on the fast beam steerability reveal advection properties and spatial variability of echoing regions in the troposphere. These results demonstrate new possibilities for this system in the investigation of three dimensional structures of turbulence.     

亚裔美国史学五十年:反思与展望

回顾和检讨亚裔美国史学在过去半个世纪里所走过的道路可以发现,早期亚裔美国史学中一个最突出的问题是以意识形态为主导的一元论历史观。在近30年的时间里,学者大都仅仅从"种族歧视"这一个角度去诠释历史事件,反对从其他视野去观察亚洲移民的经历。不过,最近15年来,这个领域中出现了冲破一元论历史观束缚的趋势。新一代学者提出了白人、黑人和亚裔之间三角形关系的论点,从而否定了"有色对白种"的双重种族关系理论模式。从"跨国主义"的视野观察亚裔美国史的人认为,亚洲移民实际上具有双重的民族主义和双重文化认同,从而向"同化论"、"定居者"论和"美国化"论提出了挑战。他们还发现,日本人向美国移民和日本帝国主义的海外扩张之间有着密不可分的关系。这些新动向标志着亚裔美国史学正在逐步走向成熟。     

十八世纪中国的"思想现代性"——"中国中心观"主导下的清史研究反思之二

本文主要从思想史的角度,选择有代表性的著作,对20世纪七八十年代以来海内外中国史学界出现的一股在近世中国内部寻找现代性的思潮进行批判性的反思,并把这一思潮置于一个更为长远的历史时段内予以考察,重在揭示其中的方法论特征。作者认为,被众多学者发现的所谓中国历史内在自发的"思想现代性",与其反映了历史的真实,不如说是这些学者的思想对中国历史的发明,而这一思想本身在很大程度上又是西方冲击的产物,蕴涵着自身难以克服的逻辑困境。     

Role of compressive tectonics on gas charging into the Ordovician sandstone reservoirs in the Sbaa Basin,Algeria: constrained by fluid inclusions and mineralogical data

Structure‐ and tectonic‐related gas migration into Ordovician sandstone reservoirs and its impact on diagenesis history were reconstructed in two gas fields in the Sbaa Basin, in SW Algeria. This was accomplished by petrographical observations, fluid inclusion microthermometry and stable isotope geochemistry on quartz, dickite and carbonate cements and veins. Two successive phases of quartz cementation (CQ1 and CQ2) occurred in the reservoirs. Two phase aqueous inclusions show an increase in temperatures and salinities from the first CQ1 diagenetic phase toward CQ2 in both fields. Microthermometric data on gas inclusions in quartz veins reveal the presence of an average of 92 ± 5 mole% of CH₄ considering a CH₄‐CO₂ system, which is similar to the present‐day gas composition in the reservoirs. The presence of primary methane inclusions in early quartz overgrowths and in quartz and calcite veins suggests that hydrocarbon migration into the reservoir occurred synchronically with early quartz cementation in the sandstones located near the contact with the Silurian gas source rock at 100–140°C during the Late Carboniferous period and the late Hercynian episode fracturing at temperatures between 117 and 185°C, which increased in the NW‐direction of the basin. During the fracture filling, three main types of fluids were identified with different salinities and formation temperatures. A supplementary phase of higher fluid temperature (up to 226°C) recorded in late quartz, and calcite veins is related to a Jurassic thermal event. The occurrence of dickite cements close to the Silurian base near the main fault areas in both fields is mainly correlated with the sandstones where the early gas was charged. It implies that dickite precipitation is related to acidic influx. Late carbonate cements and veins (calcite – siderite – ankerite and strontianite) occurred at the same depths resulting from the same groundwater precipitation. The absence of methane inclusions in calcite cements result from methane flushing by saline waters.     

Caretakers of the Earth: integrating Canadian Aboriginal perspectives on culture and sustainability into local plans

Abstract

While still contested in most jurisdictions, a consensus on the four-pillar approach to sustainable development is slowly emerging. This perspective attempts to integrate the environmental, social, economic and cultural elements of a community into local sustainability planning processes and has been widely adopted in Canada as the basis of Integrated Community Sustainability Plans. However, Aboriginal perspectives have generally been marginalised in such efforts, largely because Aboriginal peoples take a more holistic approach to both sustainability and culture than Western-educated planners and decision makers. This article examines current approaches and methodologies adopted by Aboriginal and non-Aboriginal communities in Canada to integrate culture in sustainability planning and presents several case studies that examine the application of medicine wheel and other Aboriginal integrative worldviews to community sustainability planning. It discusses whether Aboriginal perspectives on culture can provide an alternative narrative that will advance our understanding of culture’s role in community sustainability and counteract the monocultural perspectives that are the legacy of colonialism throughout the world.     

Both Ends of the Telescope: New Perspectives on FDR and American Entry into World War II

Review in this Article
Michael Barnhart. Japan Prepares for Total War: The Search for Economic Security, 1919–1941 . Ithaca
Waldo H. Heinrichs. Threshold of War: Franklin D. Roosevelt and American Entry into World War II . New York Oxford University Press, 1988. x + 279 pp.
Akira Iriye. The Origins of the Second World War in Asia and the Pacific . New York Longman, 1987.
Frederick W. Marks III. Wind over Sand: The Diplomacy of Franklin Roosevelt . Athens: University of Georgia Press, 1988. xiv + 444 pp. Notes, bibliography, index.
Jonathan G. Utley. Going to War with Japan, 1937–1941 . Knoxville: University of Tennessee Press, 1985. xiv + 238 pp. Maps, photographs, notes, bibliography, index.     

Memorialisation and remembrance: on strategic forgetting and the metamorphosis of psychiatric asylums into sites for tertiary educational provision

This paper builds on earlier investigations of psychiatric asylum closure by focusing on their not infrequent successor role as educational facilities. We ask two questions: what conditions underpin a transition to educational re-use, and how is former asylum use remembered and memorialised in the successor context? Through recounting and interpreting the histories of acquisition and adaptation at two sites (Carrington, Auckland and Lakeshore, Toronto), we build a narrative that suggests a variable response to the shadows cast by stigma and the vilification of asylum. We distinguish between memorialisation (material reminders on site) and remembrance (narratives of past use). Former asylum sites, we contend, are attractive for educational users for their campus-like settings, range of buildings and (now) suburban locations. For city residents and planners replacing one institutional use with another keeps the site green, brings employment, and retains semi-public access. Memorialisation is often strategically low-key and remembrance more personal and individual. The net result is a relict landscape that speaks to the transcendence of stigma despite the relatively recent demise of the asylum.     

A cautionary note on the use of captive carnivores to model wild predator behavior: a comparison of bone modification patterns on long bones by captive and wild lions

A study with wild lions in Tarangire National Park (Tanzania) and with captive lions in Cabárceno Reserve (Spain) has yielded two different bone modification patterns, probably as a result of the differences in environmental contexts. Captive lions have modified bones more intensively, both in the form of total number of tooth-marked bones and number of tooth marks per tooth-marked bone, probably because of stereotypic behaviors. This emphasizes the importance of environmental contexts to understand carnivore behavior and their resulting bone modification patterns. It also shows that analogical models based on experiments carried out with captive carnivores may be biased and inadequate as proxies for wild carnivore bone modification behaviors.     

Experimental study of aqueous fluid infiltration into quartzite: implications for the kinetics of fluid redistribution and grain growth driven by interfacial energy reduction

To investigate the kinetics of interfacial energy‐driven fluid infiltration, experiments were carried out in a quartzite–water system at 621–925°C and 0.8 GPa. Infiltration couples were made by juxtaposing presynthesized dry quartzite cylinders and fluid reservoirs. The infiltration process was confirmed by the presence of pores at the quartzite grain edges. As predicted from theoretical considerations and previous experiments, wetting fluids such as pure water and NaCl aqueous solution infiltrated into quartzite, whereas nonwetting CO₂‐rich fluids did not. Newly precipitated quartz layers at the surfaces of the infiltrated sample proved that infiltration took place by a dissolution–precipitation mechanism. The enhancement of grain growth by fluid infiltration was observed over the entire range of experimental temperatures. The fluid fraction, gauged by the porosity of the run products, increases at the infiltration front and then decreases towards the fluid reservoir to form a high‐porosity zone with a maximum porosity of 2.3–2.9%. As infiltration proceeds, the high‐porosity zone advances like a travelling wave. This porosity wave is probably caused by a grain curvature gradient resulting from preferential grain growth in the infiltrated part of the quartzite, perhaps combined with other factors. The infiltration kinetics were modelled with a steady‐state diffusion model over the high‐porosity zone. The solubility difference between dissolving and precipitating grains was deduced to be 2 × 10^?2?3 × 10^?1 wt %. The experimentally obtained infiltration rate of aqueous fluid in the steady‐state diffusion regime (2 ± 0.5 × 10^?8 m sec^?1 at 823°C) is much faster than the estimated metamorphic fluid flux rates, so that interfacial energy‐driven fluid redistribution in quartz‐rich layers could significantly contribute to the fluid flux in high‐grade metamorphism, at least over a short distance. Cathodoluminescence observations of the run products revealed that the grain growth of quartzite in the presence of fluid proceeds extensively, which would promote the chemical equilibration between fluid and rock more effectively than would volume diffusion in quartz crystals.     

辛酉政变与正统皇权思想--慈禧政变成功原因再探讨

1861年8月,咸丰帝弥留之际的"后事"安排,是一种意在调适权力平衡但又必然引起权力争夺的行政措施.上谕"铃印"的规定,从制度上确保了皇权不致旁落,排除了肃顺等人挟制天子的可能,但同时也为慈禧掌握清廷最高权力提供了可能和保证.慈禧与肃顺等人在慈禧的太后封号、有无干预朝政权、是否垂帘听政、辛酉政变等问题上较量的胜利,在相当大程度上皆依恃皇权代表的有利地位.当时弥漫于朝野上下的正统皇权主义思想,使许多文武大臣及封建士大夫对肃顺等人赞襄政务、辅弼幼帝的合法性与可靠性表示出普遍的怀疑.这种正统皇权主义思想才是慈禧太后发动政变成功的决定性深层次原因.它不仅影响着当时的人们,甚至影响着当代的某些史学工作者.