排序方式： 共有15条查询结果，搜索用时 328 毫秒
1.
Douglas A. Simons Paola Amico Dietrich Baade Sam Barden Randall Campbell Gert Finger Kirk Gilmore Roland Gredel Paul Hickson Steve Howell Norbert Hubin Andreas Kaufer Ralf Kohley Philip MacQueen Sergej Markelov Mike Merrill Satoshi Miyazaki Hidehiko Nakaya Darragh O'Donoghue Tino Oliva Andrea Richichi Derrick Salmon Ricardo Schmidt Hongjun Su Simon Tulloch Maria Luisa García Vargas R. Mark Wagner Olivier Wiecha Binxun Ye 《Experimental Astronomy》2005,19(1-3):15-44
Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 109 pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors – something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future. 相似文献
2.
This paper presents a typology of local‐government data sharing arrangements in the US at a time when spatial data infrastructures (SDI) are moving into a second generation. In the first generation, the US National Spatial Data Infrastructure (NSDI) theoretically involved a pyramid of data integration resting on local‐government data sharing. Availability of local‐government data is the foundation for all SDI‐related data sharing in this model. However, first‐generation SDI data‐sharing activities and principles have gained only a tenuous hold in local governments. Some formalized data sharing occurs, but only infrequently in response to SDI programmes and policies. Previous research suggests that local‐government data sharing aligns with immediate organizational and practical concerns rather than state or national policies and programmes. We present research findings echoing extending these findings to show that local‐government data sharing is largely informal in nature and is undertaken to support existing governmental activities. NSDI principles remain simply irrelevant for the majority of surveyed local governments. The typology we present distinguishes four distinct types of local‐government data sharing arrangements that reflect institutional, political, and economic factors. The effectiveness of second generation, client‐service‐based SDI will be seriously constrained if the problems of local government take‐up fail to be addressed. 相似文献
3.
Autochthonous inheritance of zircon through Cretaceous partial melting of Carboniferous plutons: the Arthur River Complex,Fiordland, New Zealand 总被引：1，自引：0，他引：1
Andrew J. Tulloch Trevor R. Ireland David L. Kimbrough William L. Griffin Jahandar Ramezani 《Contributions to Mineralogy and Petrology》2011,161(3):401-421
TIMS and SHRIMP U–Pb analyses of zircons from Milford Orthogneiss metadiorite (P = 1–1.4 GPa; T ≥ 750°C) of the Arthur River Complex of northern Fiordland reveal a bimodal age pattern. Zircons are predominantly either
Paleozoic (357.0 ± 4.2 Ma) and prismatic with oscillatory zoning, or Cretaceous (133.9 ± 1.8 Ma) and ovoid with sector or
patchy zoning. The younger age component is not observed overgrowing older grains. Most grains of both ages are overgrown
by younger Cretaceous (~120 Ma) metamorphic zircon with very low U and Th/U (0.01). We interpret the bimodal ages as indicating
initial igneous emplacement and crystallisation of a dioritic protolith pluton at ~357 Ma, followed by Early Cretaceous granulite-facies
metamorphism at ~134 Ma, during which a significant fraction (~60%) of the zircon grains dissolved, and subsequently reprecipitated,
effectively in situ, in partial melt pockets. The remaining ~40% of original Paleozoic grains were apparently not in contact
with the partial melt, remained intact, and show only slight degrees of Pb loss. Sector zoning of the Cretaceous grains discounts
their origin by solid state recrystallisation of Paleozoic grains. The alternative explanation—that the Paleozoic component
represents a 40% inherited component in an Early Cretaceous transgressive dioritic magma—is considered less likely given the
relatively high solubility of zircon in magma of this composition, the absence of 134 Ma overgrowths, the single discrete
age of the older component, equivalent time-integrated 177Hf/176Hf compositions of both age groups, and the absence of the Cambrian-Proterozoic detrital zircon that dominates regional Cambro-Ordovician
metasedimentary populations. Similar bimodal Carboniferous-Early Cretaceous age distributions are characteristic of the wider
Arthur River Complex; 8 of 12 previously dated dioritic samples have a Paleozoic component averaging 51%. Furthermore, the
age and chemical suite affinity of these and several more felsic rocks can be matched with those of the relatively unmetamorphosed
Carboniferous plutonic terrane along the strike of the Mesozoic margin in southern Fiordland, also supporting the in situ
derivation of the Carboniferous “inherited” component. 相似文献
4.
A. J. Tulloch 《Contributions to Mineralogy and Petrology》1979,69(2):105-117
Secondary Ca-Al silicates, including andradite-grossular garnet, epidote, pumpellyite, and prehnite are shown to be extremely widespread as low-grade alteration products of granitoid biotite. All may occur within metadomains on the scale of a single biotite pseudomorph. They all generally have a lensoid habit parallel to the host biotite cleavage, which may, or may not be deformed. A cleavage or parting inherited from the host biotite cleavage is usually present.Prehnite, pumpellyite and epidote are unusually Fe-rich: 100 Fe/Fe + Al for prehnite and pumpellyite reaching 19.1 and 49.1 respectively and epidote Ps36-Ps48. Garnet compositions are relatively uniform averaging approximately andradite56 grossular35 hydrogrossular7.Correlation of prehnite Fe3+ with host biotite Fe3+ and oxidation state support the textural evidence that prehnite in this paragenesis often replaces the host biotite. Sericitization of plagioclase and commonly a complete lack of hornblende indicate that plagioclase (An50-An15) is the chief source of Ca. Chlorite and muscovite (whose compositions are both directly related to the host biotite composition), aluminian sphene (Al2O3 reaching 7.72%), and K-feldspar (Or99+) are complimentary to the biotite breakdown reaction.Host rock composition to some extent controls the development of the Ca-Al silicates which do not occur in granitoids whose whole-rock CaO is less than 1%. An aqueous pore fluid with locally varying activities of ions enabled concentration of Ca in micro-metadomains, allowing development of Ca-Al silicates in relatively low-Ca granitoids. Individual phases generally appear to have developed independently due to fluctuation in chemical environment in micro-space and/or T, P fluctuation with time. Textures suggest that grandite may have locally replaced epidote in response to increasing temperature.In granitoids of the Victoria Range, South Island, New Zealand the alteration has probably occurred with P<2kb and T< 300 °–350 °C. Here alteration can be ascribed to strictly deuteric activity in only one of the two groups of granitoids so affected. 相似文献
5.
To complement previously published information on E2V CCDs, we present here some less well-known information about Marconi
CCDs. We show details of the performance of deep depletion silicon variants, and discuss other subtleties of performance.
We also present an update on L3vision (sub-electron noise) devices, indicating current availability, options, and ongoing
development work. Finally, we will give a flavour of the range of custom designs that have been made. Many of these are not
commercially available, and may not be familiar to all astronomers or CCD technologists.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
J. M. Scott J. M. Palin A. F. Cooper M. W. Sagar A. H. Allibone A. J. Tulloch 《Contributions to Mineralogy and Petrology》2011,161(5):667-681
Previous U–Pb zircon dating of the Pomona Island Granite (PIG) pluton (South Island, New Zealand) yielded either Permo-Carboniferous
or Late Jurassic ages for five samples essentially indistinguishable in their field, petrographic, and geochemical characteristics.
Detailed cathodoluminescence imaging and LA-ICP-MS dating of zircon in new and previously dated samples reveal that portions
of the pluton contain either delicately oscillatory-zoned Late Jurassic zircon grains with rare Permo-Carboniferous cores,
or Permo-Carboniferous grains with ubiquitous but thin Late Jurassic rims. Based on zircon dissolution-overgrowth textures,
zircon rim and core trace element compositions, and the limited extent of sub-solidus rock recrystallisation textures, the
bipartite age distribution is unlikely to reflect variable Pb-loss or metamorphic re-equilibration. Magmatic Zr-saturation
temperatures were ≥851°C for samples dominated by Jurassic zircon and ≤809°C for samples with a predominance of Permo-Carboniferous
zircon. Together, these data are consistent with PIG magmas having been derived from partial melting of a Permo-Carboniferous
felsic igneous source at variable temperature wholly in the Late Jurassic (157 ± 3 Ma). The lowest temperature melts would
have been incapable of dissolving significant amounts of pre-existing zircon and consequently generated inheritance-rich magmas,
with the very thin rims on the pre-existing zircon grains the only evidence of the Late Jurassic magmatic age. As the partial
melting temperature increased and nearly all pre-existing zircon grains dissolved into the magma, an inheritance-poor batch
of melt was generated, which precipitated new zircon grains upon crystallisation. Concentrations of major and many trace elements
in both magma batches may have been buffered by retention of residual quartz and feldspar in the source, which would explain
the limited geochemical differences between inheritance-rich and inheritance-poor portions. 相似文献
7.
Traditional measures of benefits have focused primarily on efficiency, with some attention directed towards effectiveness. This paper describes community systems – ostensibly multipurpose land information systems (MPLIS) – that produce three categories of benefits: efficiency, effectiveness and equity (or empowerment). Building on the theoretical model of MPLIS development, the paper defines each type of benefit and describes when and where they can be observed and how they can be measured. The understanding of system benefits promoted by this paper is significant in that it places a higher emphasis on uses of system products throughout the community beyond the agencies that initiate the systems – and therefore community benefits than previous geographic information science benefits research. 相似文献
8.
Is VGI participation? From vernal pools to video games 总被引：3，自引：0，他引：3
David L. Tulloch 《GeoJournal》2008,72(3-4):161-171
This paper examines the relationship between public participatory GIS (PPGIS) and volunteered geographic information (VGI). A brief review of the history of PPGIS reveals similarities between the two but also provides examples of how these two areas have developed in ways that cause the boundaries between them to be unclear at times. As evidence for advancing this conversation, 2 case studies are presented: volunteers mapping vernal pools and park design in Second Life. These case studies demonstrate both the intertwined nature of some aspects of VGI and PPGIS, while also showing some aspects of divergence. 相似文献
9.
David L. Tulloch 《Transactions in GIS》1999,3(3):259-283
Historically, multipurpose land information systems have often been designed for use as community-wide enterprises. Before becoming useful to the community, however, many of these systems encounter prohibitive factors delaying or preventing the satisfaction of the ultimate goals for which they were designed. A criticism of current models is that system developers seeking to build publicly accessible systems do not use them. Since most systems are developed without the guidance of a formal model, system developers often do not fully anticipate likely system issues. Many systems, designed on an ad hoc basis, fail to achieve their full potential, because they have not used an appropriate model to determine a final system outcome. This paper presents a theoretical model describing the stages systems experience during development. These stages are: no development, system initiation, database development, recordkeeping, analysis, and democratization. Additionally, the factors promoting or prohibiting movement from one stage to the next, and the indicators or outcomes of each stage are described. Not only are the individual elements described but also their relationships are described as part of the model. The Multipurpose Land Information System (MPLIS) development model is designed both as a guide for system developers and a tool for discussing and comparing systems. 相似文献
10.
Jan-Olaf Meynecke Elisa Seyboth Jasper De Bie Jan-Lukas Menzel Barraqueta Abdoulkadri Chama Subhra Prakash Dey Serena Blyth Lee Vivitskaia Tulloch Marcello Vichi Ken Findlay Alakendra Narayan Roychoudhury Brendan Mackey 《Marine Ecology》2020,41(6):e12616
Globally, baleen whales were severely depleted by historic whaling. Recovering populations have been observed to alter their behaviour. These changes have been attributed to climate change in some cases and raise concerns over the successful recovery of baleen whale populations. Current data-driven statistical habitat and behavioural models have proven useful for addressing questions of whale distribution changes within their limitations. Given observed changes in oceanic conditions, a new approach to managing baleen whale population recovery is necessary. Model predictions of future whale movements and distributions under climate change scenarios are vital to enable adequate conservation management. This paper presents a new perspective on understanding the impacts of climate change on humpback whales, arguing the need for a system-based multidisciplinary research approach. Our approach includes coupled, mechanistic models based upon robust ecological principles, and integrates key physical, biogeochemical, biological and ecological modules to address long-term changes associated with climate change. To illustrate the need for this system-based multidisciplinary approach, we focus on Southern Hemisphere humpback whales, the recovery of which may be impacted by rapid changes in habitat conditions brought about by anthropogenic climate change. 相似文献