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排序方式: 共有418条查询结果,搜索用时 15 毫秒
411.
Equipped to deal with uncertainty in climate and impacts predictions: lessons from internal peer review 总被引:1,自引:0,他引:1
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413.
Indigenous peoples have been enrolled in climate change research for decades, participating in data-gathering, as writing collaborators, and serving as the symbolic “canary in the coal mine” for public outreach and policy-making. They have indeed experienced some of the most rapid environmental changes, but rather than emphasize their vulnerabilities, we argue their expertise is narrowly understood in formulating knowledge; the research on climate change has a limited understanding of what it might mean to be inter- or trans-disciplinary because research is formulated exclusively through the assumptions of Enlightenment thought, without sufficiently engaging non-Western subjectivities. Qualitative social sciences and “Indigenous methodologies” can be used to better achieve trans-disciplinarity; in this article we re-tell a story told by Native elders from tribes across Alaska about the “man on the moon.” While literally referring to the US moon landing, elders invoke this story when addressing climate change: it teaches the ethics of the human-nature relationship, developed from a “more-than-human” (or “posthuman”) philosophy. Our data comes from participant-observation and oral history; we draw upon poststructuralist theory, and frame our analysis through the literatures of critical geography, science studies, and American Indian studies. To ensure that Indigenous peoples are not used as props in Western policy agendas, researchers must engage with non-Enlightenment intellectual traditions. More than being a source of data or a symbol of humanity’s ruin, Indigenous wisdom can productively inform sustainable policy agendas to adapt to climate change. What can be learned, for example, is a more-than-human ethics of place and space. 相似文献
414.
TitaniQ: a titanium-in-quartz geothermometer 总被引:21,自引:10,他引:11
Titanium is one of many trace elements to substitute for silicon in the mineral quartz. Here, we describe the temperature dependence of that substitution, in the form of a new geothermometer. To calibrate the “TitaniQ” thermometer, we synthesized quartz in the presence of rutile and either aqueous fluid or hydrous silicate melt, at temperatures ranging from 600 to 1,000°C, at 1.0 GPa. The Ti contents of quartz (in ppm by weight) from 13 experiments increase exponentially with reciprocal T as described by:
Application of this thermometer is straightforward, typically requiring analysis of only one phase (quartz). This can be accomplished either by EPMA for crystallization temperatures above 600°C, or by SIMS for temperatures down to at least 400°. Resulting temperature estimates are very precise (usually better than ±5°C), potentially allowing detailed characterization of thermal histories within individual quartz grains. Although calibrated for quartz crystallized in the presence of rutile, the thermometer can also be applied to rutile-absent systems if TiO2 activity is constrained. 相似文献
415.
Temporospatial dynamics and public health significance of bacterial flora identified on a major leatherback turtle (Dermochelys coriacea) nesting beach in the Southern Caribbean 下载免费PDF全文
Ayanna Carla N. Phillips Johanna Coutou Stacy Rajh Neville Stewart Antonio Watson Adam Jehu Hamish Asmath Francis Dziva Chandrashekhar Unakal Ridley Holder Raymond Raoul Carthy 《Marine Ecology》2017,38(2)
Grande Riviere beach, on the island of Trinidad, supports the largest nesting population of leatherback turtles in the Caribbean region. Throughout the nesting season, nests are naturally disturbed by newly nesting females, resulting in egg breakage and loss of some nest viability. This environment is ideal for the growth and proliferation of microorganisms. The range of bacterial flora present in beach sand and egg shells was examined, with emphasis on bacteria that may pose a threat to public and animal health. The extent to which the bacterial load and genera on the beach changed throughout the season was also assessed. Twenty‐five genera were identified, with Pseudomonas spp. found to be the most predominant environmental bacteria. Four genera identified possess zoonotic potential, while five additional genera are known to be of public and animal health significance. Distinct shifts in the density and distribution of bacteria were observed along the beach from early to peak nesting season. Shifts were seen across heavily traversed zones, thus highlighting the potential exposure threats posed to beach visitors and animals alike. Further studies aimed at speciating this population of bacteria, as well as isolating potential fungal pathogens may mitigate this threat. Identification of bacterial agents that are specifically pathogenic to leatherback turtles, turtle eggs, hatchlings and those who may interact with these animals will serve to enhance and guide efforts to better conserve this species and protect the health of all who visit this ecologically significant site. 相似文献
416.
Patty Jo Watson 《Geoarchaeology》2008,23(1):173-175
The Neolithic revolution in the Near East: Transforming the human landscape. Alan H. Simmons, 2007, The University of Arizona Press, Tucson, Arizona, xvii +339 pp., $55.00 (cloth). 相似文献
417.
Abandoned channel fill sequences in the tidal estuary of a small mountainous,dry‐summer river 下载免费PDF全文
Andrew B. Gray Gregory B. Pasternack Elizabeth B. Watson Miguel A. Goñi 《Sedimentology》2016,63(1):176-206
This study proposes a modification of the current model for abandoned channel fill stratigraphy produced in unidirectional flow river reaches to incorporate seasonal tidal deposition. Evidence supporting this concept came from a study of two consecutive channel abandonment sequences in Ropers Slough of the lower Eel River Estuary in northern California. Aerial photographs showed that Ropers Slough was abandoned around 1943, reoccupied after the 1964 flood, and abandoned again in 1974 with fill continuing to the present. Planform geomorphic characteristics derived from these images were used in conjunction with sub‐centimetre resolution stratigraphic analyses to describe depositional processes and their resultant sedimentary deposits. Both abandonment sequences recorded quasi‐annual scale fluvial/tidal deposition couplets. In both cases, tidal deposits contained very little sand, were higher in organic and inorganic carbon content than the sandier, fluvially dominated deposits, and possessed millimetre‐scale horizontal laminations. The two abandonment fills differed significantly in terms of the temporal progression of channel narrowing and fluvial sediment deposition characteristics. Aerial photographic analysis showed that the first abandonment sequence led to a more rapid narrowing of Ropers Slough and produced deposits with a positive relationship between grain size/deposit thickness and discharge. The second abandonment resulted in a much slower narrowing of Ropers Slough and generally thinner fluvial deposits with no clear relationship between grain size/deposit thickness and discharge. The δ13C values and organic nitrogen to organic carbon ratios of deposits from the first phase overlapped with Eel River suspended sediment characteristics found for low flows (one to five times mean discharge), while those of the second phase were consistent with suspended sediment from higher flows (seven to ten times mean discharge). When considered together, the results indicate that the early fill sequence recorded a reach experiencing regular fluvial deposition through flow conditions during the wet season, while the latter fill sequence records a reach more disconnected from the main stem in terms of flow and sediment. The major factor affecting the difference in sedimentation between the two fill periods appears to have been the morphology of the upstream river bend in relation to the position of the bifurcation node. During the first fill period, the upstream entrance to Ropers Slough seems to have remained open, in part due to the placement of its entrance on the outside of the mainstem river bend, and despite stronger tidal effects caused by a larger tidal prism and closer proximity to the tidal inlet. By the second fill sequence, the upstream bend morphology had altered, placing the entrance to Ropers Slough on the inner bank of the mainstem bend, which resulted in more rapid plug bar formation. The role of tidal effects in the geomorphic trajectory of the two abandonment sequences is unclear, but appears to have been less important than local bifurcation geometry. 相似文献
418.
E. Watson 《Geological Journal》1971,7(2):381-392
Remains of pingos have already been reported from east central Wales. This paper records a further group from west central Wales and a probable group from the Isle of Man. When they are compared with contemporary pingos it is clear that they belong to the open system type, which, in contrast with the solitary pingo of the closed system type, tends to occur in clusters of mutually interfering forms and on melting to result in a complex pattern of ramparts. Much of the recently discovered group in central Wales shows this complexity and suggests later pingos developing on the sites of earlier ones as the injection centres migrated upslope. On more open sites simpler solitary pingos occur, including some elongated forms. The Isle of Man group consists of depressions without ramparts but their location and orientation suggest they represent pingo basins. It is argued that although the most convincing evidence for pingos consists of arcuate to annular ramparts enclosing basins, the ramparts may disappear through cultivation. 相似文献