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81.
Digital building information is important during a building's lifecycle, it is needed from first design until demolition. The two domains that mainly contribute are AEC (architecture, engineering, and construction) during design, construction, and operation, and GIS as a supporting discipline for analysis and further integration of the building's environment. However, there is a challenge in information exchange between the two domains, resulting in the remodeling of digital building information in GIS. In this article, we identify three major data sources from the AEC domain and show transformation processes to enable the integration of such models into the geographical environment in the form of one transition model. Furthermore, we show that this model can either be used directly or exported in the form of de facto standards that allow for further analysis.  相似文献   
82.
We review the current knowledge about Southeast Asian volcanoes and their eruption histories, and focus on identifying tephrochronologic markers representing major explosive eruptions in order to further future palaeoclimate and volcanological studies. Forty-one volcanic edifices in Southeast Asia have been classified as large calderas by Whelley et al. (2015) and thus have, or are likely to have, produced large explosive eruptions with a Volcanic Explosivity Index (VEI) of 6–8. Unfortunately, only 20 such eruptions have known ages, spanning from 1.2 Ma to 1991 ad , and fewer have geochemical data that can be used for tephrostratigraphic correlations. Volcanic products from different geodynamic regions and different sources can generally be distinguished on major element plots (e.g. K2O versus CaO) of matrix glass composition. However, the distinction of multiple eruptions from the same source often requires additional data such as trace element compositions of matrix glass and/or mineral compositions. Biotite, but also magnetite compositions (MgO and TiO2 content in particular) appear to be very discriminating. Up to nine tuffs in addition to the three to four Toba tuffs can be utilised as widespread tephrochronologic markers and span a range from 1.2 to 1.6 Ma to recent. As only a few Holocene major eruptions have been well characterised and dated, many large calderas are still unstudied, and many distal tephra layers are still lacking a source, more tephrochronologic markers can certainly be defined in the future.  相似文献   
83.
The distribution of transparent exopolymer particles (TEP) was investigated during a coccolithophorid bloom in the northern Bay of Biscay (North Atlantic Ocean) in early June 2006. MODIS chlorophyll-a (Chl-a) and reflectance images before and during the cruise were used to localize areas of important biological activity and high reflectance (HR). TEP profiles along the continental margin, determined using microscopic (TEPmicro) and colorimetric (TEPcolor) methods, showed abundant (6.1×106–4.4×107 L?1) and relatively small (0.5–20 μm) particles, leading to a low total volume fraction (0.05–2.2 ppm) of TEPmicro and similar vertical profiles of TEPcolor. Estimates of carbon content in TEP (TEP-C) derived from the microscopic approach yielded surface concentration of 1.50 μmol C L?1. The contribution of TEP-C to particulate organic carbon (POC) was estimated to be 12% (molar C ratio) during this survey. Our results suggest that TEP formation is a probable first step to rapid and efficient export of C during declining coccolithophorid blooms.  相似文献   
84.
Abstract— In this edition of The Meteoritical Bulletin, 1394 recognized meteorites are reported, 27 from specific locations within Africa, 133 from Northwest Africa, 1227 from Antarctica (from ANSMET, PNRA, and PRIC expeditions), and 7 from Asia. The Meteoritical Bulletin announces the approval of four new names series by the Nomenclature Committee of the Meteoritical Society, two from Africa and one from Asia, including Al Haggounia, from Al Haggounia, Morocco, which is projected to be on the order of 3 metric tons of material related to enstatite chondrites and aubrites. Approved are two falls from Africa, Bassikounou (Mauritania) and Gashua (Nigeria). Approved from areas other than Antarctica are one lunar, two Martian, 32 other achondrites, three mesosiderites, two pallasites, one CM, two CK, one CR2, two CV3, one CR2, and four R chondrites. The Nomenclature Committee of the Meteoritical Society announces 48 newly approved relict meteorites from two new name series, Österplana and Gullhögen (both from Sweden).  相似文献   
85.
Experimental phase equilibrium studies are increasingly beingused for the determination of intensive variables (P, T, fH2O,fO2 ) in silicic to intermediate magmas. In contrast, silicicigneous bodies are now perceived as open, periodically recharged,systems involving only limited chemical equilibration. Thus,the use of laboratory-determined crystal–liquid equilibriumdata needs clarification. Here we review the field, petrologicaland geochemical evidence concerning states and scales of chemicalequilibrium in silicic magma bodies. It is concluded that totalchemical equilibrium is generally not the rule. However, a subsystemin local equilibrium (the reactive magma) can be identified.Equilibration scales in silicic magmas are rate-limited eitherby diffusive flux in crystals (DICL regime) or by diffusiveflux in the melt (MD regime). The recognition that equilibriumin magmas is limited to a reactive subsystem requires phaseequilibrium studies to be chemically scaled. Experiments, eitherof total or partial equilibrium type, should aim at a closereproduction of equilibrium states specific to natural systems.The laboratory reconstruction of the natural equilibrium statesguarantees a precise determination of the pre-eruptive parametersand a reliable application of the experimental data to activevolcanic systems. KEY WORDS: silicic magmas; chemical equilibrium; timescales; experimental studies  相似文献   
86.
In recent literature, projects are mostly seen as an efficient form of organization which is particularly suited for mastering tasks of high complexity and creativity and adapting to changing economic and institutional conditions. This paper challenges the assumption that inter-firm projects are persistent organizational arrangements of production in the advertising industry and presents a novel argument about the potential threats to forms of project organization in crisis situations. By exploring the cases of Frankfurt/Main and Leipzig (East Germany), we show that the organization of production is substantially affected by periods of economic crisis or political transformation. We demonstrate that inter-firm projects might be replaced by more durable organizational configurations or might not be viewed as viable options in situations of severe rupture. This applies particularly to the cooperative arrangements in the creative process and leads to an organizational paradox. Although creativity is often a pivotal force to gain competitive advantage, the advertising agencies respond to the challenges of crises by reducing cooperation with external partners to a minimum and sometimes fully rely on in-house personnel. This threatens the potential of the respective firms to develop innovative and creative ideas which would enable the firms to acquire new customers and market segments. Instead of trying to overcome crises by focusing on their creative capabilities, many advertising agencies develop a cost-cutting strategy and rely on more durable network-forms of organization instead of inter-firm projects.  相似文献   
87.
This paper presents new evidence from the Dhamar highlands, Yemen, of paleohydrologic response to fluctuations in Holocene climate. Stratigraphic, geochemical, and chronological analyses of highland peat and lacustrine deposits contribute to knowledge of the timing of early Holocene moisture changes on the Arabian Peninsula, providing a backdrop to understanding early cultural development in the Arabian highlands. The location of the Dhamar highlands, characterized by intermontane valleys surrounded by the highest mountains on the Arabian Peninsula and adjacent to the Indian Ocean is ideal for examining the influence of the Indian Ocean Monsoon (IOM) on the moisture history of this region. Fluctuations in the lacustrine and paleosol records of the Dhamar highlands reflect both local changes in paleohydrology and regional influences on the Holocene paleoclimatic conditions in southwest Arabia. In addition, a peat deposit with a radiocarbon age of 10,253 – 10,560 cal yr BP documents some of the earliest Holocene high moisture conditions on the Arabian Peninsula.  相似文献   
88.
Powder IR spectra of synthetic richterite-tremolite and Sr-tremolite-tremolite solid solutions were obtained in the spectral range between 1400 and 600?cm?1. Under the consideration of the crystal structure and the Wykoff positions of the atoms in the primitive unit cell, the number, type and symmetry of vibrational modes were deduced. The space group of tremolite C2h was used as the factor group leading to 16 theoretical stretching vibrations in the IR range caused by the Si4O11 -ribbon. The energy of the internal vibrations of the Si4O11 -ribbon is a function of the relative bond strengths and masses of nearby ions. For the amphiboles a one-mode behavior was observed for all the Si-O, Si-O-Si and O-Si-O stretching vibrations, indicating no clustering in the two solid solution series. In both solid solution series the vibrational energy of the stretching vibrations is a linear function of composition. In the system richterite-tremolite a shift of the stretching frequencies of the Si4O11 -ribbon over the whole compositional range of up to 30?cm?1 was observed. In contrast, for Sr-tremolite-tremolite the maximum shift was only 5?cm?1. These quite small band shifts allow the (Si4O11)-ribbon to be treated as an isolated entity for factor group analysis. Nevertheless, by the two exchange mechanisms, Ca(M4)???Sr(M4) and □(A) Ca(M4)???Na(A)Na(M4), the FWHHs increased and the amplitudes decreased, indicating a slight distortion of the ribbon. For Sr-tremolite-tremolite only a linear expansion of the lattice was observed. In the series richterite-tremolite individual bond angles of the SiO4 tetrahedra are additionally changed, causing the higher energy shift of the bands. The strongest and sharpest bands were observed for the end member tremolite. The one-mode behavior of the Si4O11-double chain indicates that there is no short-range order of Na/Ca and Ca/Sr at the M4 sites of these amphiboles.  相似文献   
89.
90.
Tree-ring reconstructed dry season rainfall in Guatemala   总被引:1,自引:0,他引:1  
Climate Dynamics - Drought in Guatemala has negative consequences for agriculture and potable water supplies, particularly in regions of the country with highly seasonal rainfall. General...  相似文献   
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