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181.
S. Christopher BENNETT 《地球学报》2010,31(Z1):5-6
In 1996 Bennett published a cladistic analysis of the Archosauromorpha with 14 taxa and 126 characters, combining all the characters from several previous analyses (e.g., Gauthier 1984, Sereno and Arcucci 1990, Benton and Clark 1988) unless justification for discarding a character could be presented. 相似文献
182.
Tatyana K. Dimitrova Erwin L. Zodrow Christopher J. Cleal Barry A. Thomas 《Geological Journal》2010,45(4):388-396
The palynology of clastic samples from seven stratigraphical levels in the late Moscovian Sydney Mines Formation, exposed along the shore at Bras d'Or, Nova Scotia, has been investigated. Most of the samples were from roof shales of major coals; the one sample that was not yielded a much higher proportion of pollen derived from extra‐basinal vegetation. The four stratigraphically lower roof shale samples yielded essentially similar palynological spectra, with 39 ± 4% lycophytes, 9 ± 4% sphenophylls, 23 ± 4% tree‐ferns, 12 ± 4% other ferns and 5 ± 3% cordaites. The palynology of the upper part of the investigated succession suggests a shift in vegetation towards one favouring more marattialean tree‐ferns, cordaites and conifers, and fewer lycophytes. This correlates with changes in drainage patterns as the alluvial plain migrated seawards and thus changed water tables. No evidence was found to suggest significant climate change at this time. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
183.
184.
Morphological and morphometric analysis of variation in the Zhoukoudian Homo erectus brain endocasts
The six Zhoukoudian (ZKD) Locality 1 Homo erectus specimens derive from stratigraphic levels 11–3 with a geochronological span of approximately 0.3 Ma. This paper introduces the history of the ZKD endocasts and presents data on their morphological features and linear dimensions in order to evaluate variability in the sample over time and in the broader context of human brain evolution using a comparative sample of African and other Asian H. erectus fossils and modern Chinese males. The ZKD brains are very similar in their morphological characteristics, but there are also significant but subtle changes involving expansion of the frontal and occipital lobe breadths that correlate with the geochronology. The same is not true for general endocranial volume. The ZKD brains, together with other Asian and African H. erectus specimens, have low height dimensions and short parietal chords that distinguish them from the modern Chinese. Furthermore, the lack of geographical patterning in the fossil sample, as determined by Principal Components Analysis, provides no support for arguments advocating the splitting of H. erectus into separate taxa. 相似文献
185.
186.
The rapid proliferation of Phragmites australis in North America has challenged resource managers to curb its expansion and reduce the loss of functional tidal marsh. We
investigated whether native plant competition could reduce the ability of Phragmites to invade a tidal marsh, and if plant diversity (species richness, evenness, and composition) altered the competitive outcome.
Immature Phragmites shoots and four native halophytes were transplanted to small but dense field plots (~1,200 shoots m−2) comprising three community structure types (Phragmites alone, Phragmites + 1 native species, and Phragmites + 4 native species). Interspecific competition significantly reduced Phragmites aboveground biomass, shoot length production, density, and survival by approximately 60%. Additionally, plots planted with
greater native diversity contained Phragmites with the lowest growth and survival, potentially indicating diversity-enhanced resource competition. Competition consistently
reduced the growth of Phragmites even under favorable conditions: lack of strong tidal flooding stresses as well as elevated nutrient pools. 相似文献
187.
Patrick J. A. Hill Libby D. Tunney Christopher D. K. Herd 《Meteoritics & planetary science》2023,58(3):421-432
The rapid recovery of meteorites mitigates the exposure of astromaterials to the terrestrial environment and subsequent contamination. Modern fireball observatories have enabled the more accurate triangulation of fireball trajectories, which has aided in the location of strewn fields, in the case of meteorite-producing events. Despite this advancement, most meteorite searches still use manual searching to locate any meteorite falls, which is often labor-intensive and has a slow coverage rate (km2 day−1). Recent work has begun exploring the application of drone technology to the recovery of meteorites; however, most of this work has focused on falls in arid environments. Our study examines the utilization of drones with thermal imaging technology to aid in the recovery of meteorites that have fallen on a snow-covered field. We created a simulated strewn field that included meteorite specimens as well as Earth rocks with similar properties (“meteowrongs”). Thermal imagery was utilized to determine whether the thermal contrast between meteorites and snow could aid in the identification of meteorites. We found that the thermal contrast was significant enough that meteorites were readily identifiable within thermal images; however, it was not significant enough to distinguish between the meteorites and the meteowrongs. The utilization of thermal imagery in conjunction with visible imagery has the potential to aid in the rapid recovery of meteorites in snow-covered landscapes. 相似文献
188.
Thilo Wrona Alexander C. Whittaker Rebecca E. Bell Robert L. Gawthorpe Haakon Fossen Christopher A.-L. Jackson Marit Stokke Bauck 《Basin Research》2023,35(2):744-761
Our understanding of continental rifting is, in large parts, derived from the stratigraphic record. This record is, however, incomplete as it does not often capture the geomorphic and erosional signal of rifting. New 3D seismic reflection data reveal a Late Permian-Early Triassic landscape incised into the pre-rift basement of the northern North Sea. This landscape, which covers at least 542 km2, preserves a drainage system bound by two major tectonic faults. A quantitative geomorphic analysis of the drainage system reveals 68 catchments, with channel steepness and knickpoint analysis of catchment-hosted palaeo-rivers showing that the landscape preserved a >2 Myr long period of transient tectonics. We interpret that this landscape records a punctuated uplift of the footwall of a major rift-related normal fault (Vette Fault) at the onset of rifting. The landscape was preserved by a combination of relatively rapid subsidence in the hangingwall of a younger fault (Øygarden Fault) and burial by post-incision sediments. As such, we show how and why erosional landscapes are preserved in the stratigraphic record, and how they can help us understand the tectono-stratigraphic evolution of ancient continental rifts. 相似文献
189.
Claire Kain Christopher Gomez Patrick Wassmer Franck Lavigne Deirdre Hart 《New Zealand geographer》2014,70(3):165-178
The 2004 tsunami transformed the coast of Indonesia. This research investigates a sand dune area in Lampuuk, Sumatra, that was scoured by tsunami flow. We assessed geomorphology one‐year post‐event and examine the timescale of vegetation recovery. Ground Penetrating Radar (GPR) evidence shows an eroded succession of thin dipping units, overlain by aeolian layers 0 to 50 cm thick. Incipient dunes were absent, indicating limited dune rebuilding at one‐year post‐tsunami, possibly resulting from channelised airflow and the absence of vegetation. Recolonisation by vegetation was initially limited but progressed rapidly between 2005 and 2011, highlighting the temporal non‐linearity of recovery processes. 相似文献
190.
Christopher Gomez 《New Zealand geographer》2014,70(2):140-145
This article presents the cartoons and comic strips that the author draws and has used in his teaching of physical geography at the undergraduate level since 2011. In the context of an image‐based culture, this article discusses the pedagogic goals that cartoons and comic strips fulfil: enhancing learning and creativity, associating pleasure with learning, pushing students to think ‘outside the box’ and relating the students' learning experience to a media framework popular with students. Cartoons and comic strips also answer particular necessities related to the teaching of physical geography. Using characters placed in hypothetical situations, they explain the process of doing geography and being a physical geographer. 相似文献