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81.
Heather Norris Nicholson 《GeoJournal》2004,59(4):323-333
After the appearance of a portable Kodak cine camera in 1923, home moving making grew steadily in popularity in the years
leading up to and following World War II. Cine enthusiasts, particularly in the pre-war period, tended to be male, white and
middle class, although exceptions exist, and they tended to travel with their cameras much as earlier generations had documented
their experiences in written and artistic form. Despite their amateur status, they were often very professional in their approach
to cinematography and they produced material for a range of domestic and public audiences on varied topics and in different
genres. Specialist publications and the rapid growth of local amateur film societies fostered the rise of an active non-professional
film movement; the result is a highly distinctive although neglected component of film history. With reference to materials
held at the North West Film Archives in Manchester, England, this discussion considers the rise of non-professional filmmaking
at the regional level during the decades before and after the second world war. Making and showing home movies is placed within
various socio-cultural contexts. The imagery discloses much about visual practice, including filmmakers' perceptions and their
relationships with different kinds of subject matter. The making of holiday footage, in Mediterranean settings, and its subsequent
screening in domestic or public places, connects with broader issues of visualization, social practice and leisure-related
consumption.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
82.
Leslie H. Taylor Shawn M. Shellito Heather U. Abello Peter A. Jumars 《Estuaries and Coasts》2005,28(4):500-509
Acoustic backscatter from an active sonar system over a range of six frequencies between 265 kHz and 3 MHz in the tidally
dominated Damariscotta River estuary, Maine, United States, revealed that the major emergence event of the night commenced
on the first tidal deceleration after dark (3.5–4 h after local slack), irrespective of flow direction. Emergence traps identified
the mysid shrimp,Neomysis americana, as the dominant migrator. Water-column-integrated, acoustically estimated biovolume at our 10-m deep study location increased
by a factor of about 6 during these large events, entirely dominating the holoplanktonic contribution and likely being a major
component in benthic-pelagic coupling. Application of the same algorithm used to locate this nighttime emergence revealed
a parallel but considerably smaller daytime emergence event near the same phase of the tide. Daytime trap samples failed to
recover the organisms responsible, but transmissometry rejected the alternative hypothesis that we observed resuspension events.
We suspect, but have yet only weak evidence, that animals emerging in daylight are copepods rather than mysids. 相似文献
83.
Seismogenic zone structure beneath the Nicoya Peninsula, Costa Rica, from three-dimensional local earthquake P- and S-wave tomography 总被引:3,自引:0,他引:3
84.
Heather Clegg Brian Horsfield Heinz Wilkes Jaap Sinninghe Damst Martin P. Koopmans 《Organic Geochemistry》1998,29(8):1953-1960
Hydrous pyrolysis experiments were performed on the Ghareb Formation (Upper Cretaceous, Jordan), a carbonate- and organic-rich (TOC 19.6%) source rock, using a temperature range of 200 to 360°C (72 h). The original sediment contains only low amounts of carbazoles, (maximum 2.2 μg/g bitumen for 1-methylcarbazole). With increasing thermal maturation, intense generation begins at temperatures only in excess of 300°C, reaching a maximum at 360°C. Likewise, during natural maturation, generation occurs at later stages of maturity (e.g. for Tithonian source rocks at >0.81% Rr and for Posidonia Shale at >0.88% Rr). Some isomeric changes during hydrous pyrolysis do not resemble those in nature whereas others do. The relative abundances of selected C1- and C2-alkylcarbazoles on ternary diagrams reveal differences, whereas the benzo[a]carbazole/benzo[a]carbazole+benzo[c]carbazole ratio is closely similar. The latter result supports the contention that maturation plays a key role in controlling carbazole distributions in source rocks. However, the results for alkylcarbazoles, especially the C2-carbazoles, are not easy to interpret. 相似文献
85.
86.
Brian Fry Donald M. Baltz Mark C. Benfield John W. Fleeger Arian Gace Heather L. Haas Zoraida J. Quiñones-Rivera 《Estuaries and Coasts》2003,26(1):82-97
Brown shrimp (Farfantepenaeus aztecus) are an important commercial aquatic species experiencing loss of inshore marsh nursery habitat in coastal Louisiana. To
study inshore brown shrimp movements and identify aspects of essential habitat important for sustaining brown shrimp populations,
we collected juvenile brown shrimp in April and May 2000, the time of annual maximum brown shrimp abundance, in a small 1-km2 marsh area on the central Louisiana coast. Drop sampling showed average shrimp densities of 1.6–2.4 m−2 in shallow marsh ponds and seining indicated lower densities of 0.5–0.9 m−2 in nearby shallow channel and open bay sites. Smaller shrimp (< 50 mm) fed disproportionately on benthic diatoms and small
harpacticoid copepods, while large shrimp fed more frequently on larger-bodied amphipods and tanaids. We developed novel chemical
approaches to estimate patterns of shrimp residency and movement using carbon and nitrogen stable isotopic determinations.
Resident shrimp had isotopic values similar to average foods and showed consistent isotopic spacings between fast and slow
turnover tissues. Residency was highest (47–55%) in ponds and shallow channel habitats and much less in open bays and deep
channels (4–27%). There was sparse evidence for dietary specialization among individull shrimp. The results support the view
that small 10–20 mm postlarval and juvenile brown shrimp arriving in estuaries from offshore waters continue movement through
sub-optimal habitats (deep channels and open bays), but exhibit much less movement once an optimal habitat (marsh ponds or
shallow channel margins) is reached. This study also indicated that combining estimates of shrimp densities, residency, growth
rate, and mortality allows evaluation of the importance of different habitat types for shrimp production. Shallow ponds that
in many ways resemble fertile aquaculture ponds appear to be hot spots for brown shrimp production, and coastal preservation
and restoration efforts should focus on these areas as important for sustaining shrimp fisheries. 相似文献
87.
88.
Hugh G. Smith Andrés Peñuela Heather Sangster Haykel Sellami John Boyle Richard Chiverrell Daniel Schillereff Mark Riley 《地球表面变化过程与地形》2018,43(10):2089-2105
Agricultural land management requires strategies to reduce impacts on soil and water resources while maintaining food production. Models that capture the effects of agricultural and conservation practices on soil erosion and sediment delivery can help to address this challenge. Historic records of climatic variability and agricultural change over the last century also offer valuable information for establishing extended baselines against which to evaluate management scenarios. Here, we present an approach that combines centennial‐scale reconstructions of climate and agricultural land cover with modelling across four lake catchments in the UK where radiometric dating provides a record of lake sedimentation. We compare simulations using MMF‐TWI, a catchment‐scale model developed for humid agricultural landscapes that incorporates representation of seasonal variability in vegetation cover, soil water balance, runoff and sediment contributing areas. MMF‐TWI produced mean annual sediment exports within 9–20% of sediment core‐based records without calibration and using guide parameter values to represent vegetation cover. Simulations of land management scenarios compare upland afforestation and lowland field‐scale conservation measures to reconstructed historic baselines. Oak woodland versus conifer afforestation showed similar reductions in mean annual surface runoff (8–16%) compared to current moorland vegetation but a larger reduction in sediment exports (26–46 versus 4–30%). Riparian woodland buffers reduced upland sediment yields by 15–41%, depending on understorey cover levels, but had only minor effect on surface runoff. Planting of winter cover crops in the lowland arable catchment halved historic sediment exports. Permanent grass margins applied to sets of arable fields across 15% or more of the catchment led to further significant reduction in exports. Our findings show the potential for reducing sediment delivery at the catchment scale with land management interventions. We also demonstrate how MMF‐TWI can support hydrologically‐informed decision making to better target conservation measures in humid agricultural environments. Copyright © 2018 John Wiley & Sons, Ltd. 相似文献
89.
Heather B. Franz Nanping Wu James Farquhar Anthony J. Irving 《Meteoritics & planetary science》2019,54(12):3036-3051
The isotopic composition and abundance of sulfur in extraterrestrial materials are of interest for constraining models of both planetary and solar system evolution. A previous study that included phase‐specific extraction of sulfur from 27 shergottites found the sulfur isotopic composition of the Martian mantle to be similar to that of terrestrial mid‐ocean ridge basalts, the Moon, and nonmagmatic iron meteorites. However, the presence of positive Δ33S anomalies in igneous sulfides from several shergottites, indicating incorporation of atmospherically processed sulfur into the subsurface, complicated this interpretation. The current study expands upon the previous work through analyses of 20 additional shergottites, enabling tighter constraints on the isotopic composition of juvenile Martian sulfur. The updated composition (δ34S = ?0.24 ± 0.05‰, Δ33S = 0.0015 ± 0.0016‰, and Δ36S = 0.039 ± 0.054‰, 2 s.e.m.), representing the weighted mean for all shergottites within the combined population of 47 without significant Δ33S anomalies, strengthens our earlier result. The presence of sulfur isotopic anomalies in igneous sulfides of some meteorites suggests that their parent magmas may have assimilated crustal material. We observed small negative Δ33S anomalies in sulfides from two meteorites, NWA 7635 and NWA 11300. Although negative Δ33S anomalies have been observed in nakhlites and ALH 84001, previous anomalies in shergottites have all shown positive values of Δ33S. Because NWA 7635 has formation age of 2.4 Ga and is much more ancient than shergottites analyzed previously, this finding expands our perspective on the continuity of Martian atmospheric sulfur photochemistry over geologic time. 相似文献
90.
Turner-McGrievy Gabrielle Karami Amir Monroe Courtney Brandt Heather M. 《Natural Hazards》2020,103(1):1035-1049
Natural Hazards - Little is known about what foods/beverages (F&B) are common during natural disasters. The goal of this study was to track high-frequency F&B mentions during four... 相似文献