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101.
During R.R.S. Discovery Cruise 100 in the Southern Ocean (1979), 620 specimens of the Antarctic cranchiid squid Galiteuthis glacialis (Chun) were caught in the RMT8 opening-closing net, to the south of the Antarctic Polar Front (APF). The catch was dominated by individuals <20 mm dorsal mantle length (DML) and, apart from two specimens, the rest of the catch was <60 mm DML. Two larger squid (255 mm DML) were both immature and apparently female. The species is concentrated at a depth of 300 to 400 m; there is evidence of ontogenetic spreading and a shift in the modal depth of the population from the 300 to 400 m horizon in daylight to the 200 to 300 m horizon in darkness. The collection confirms the circumpolar distribution of the species and supports previous evidence that it rarely, if ever, occurs to the north of the APF. As in Mesonychoteuthis hamiltoni, the only other species of cranchiid squid known to occur south of the APF, the early-life phase of G. glacialis is concentrated in the upper zone of the warm deep water beneath the Antarctic surface layer where, putatively, there is a zone of enhanced biological activity.  相似文献   
102.
A chorion villus sample (CVS) biopsied at 11 weeks' gestation for raised nuchal translucency, revealed monosomy X (presumptive 45,X karyotype) by QF-PCR for rapid aneuploidy testing for chromosomes 13, 18, 21, X and Y. Long-term culture gave the karyotype: 47,XY,+ 21[66]/49,XYY,+ 21,+ 21 [22]. This discrepancy prompted redigestion of the combined residual villus fragments from the original QF-PCR assay. The repeat QF-PCR assay identified the presence of trisomy 21 and a Y chromosome consistent with a 47,XY,+ 21 karyotype. A double non-disjunction event early in embryogenesis in a 47,XY,+ 21 conceptus with subsequent cell lineage compartmentalisation of the three observed cell lines (45,X; 47,XY,+ 21 and 49,XYY,+ 21,+ 21) would account for these results. This is the first reported case to describe complete discrepancy at diagnosis between abnormal karyotypes detected by QF-PCR rapid aneuploidy testing and a cultured karyotype in the same CVS. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
103.
Predation on gibbons is rarely observed in the wild. However, the gibbons' moderate body size and relatively small social groups suggest high vulnerability to predation. To assess the role of predation and to study their anti-predator behaviour, we presented visual predator models to nine groups of wild white-handed gibbons at Khao Yai National Park, Thailand. We measured subjects' immediate and delayed responses to four potential predators: tiger, clouded leopard, crested serpent eagle and reticulated python. Subjects reliably approached all four predators. In response to tigers and leopards, they additionally produced predator-specific songs and defecated copiously. In terms of delayed responses, distance between mated adults decreased, but only after exposure to the tiger model. In response to eagles and pythons, gibbons consistently vocalised, but this did not always include predator singing, and we found no long-term effects in overall activity or strata use. However, during 6 of 26 predator encounters, the gibbons produced songs with a structure that was intermediate between a duet song and a predator song more than 20 min after the predator encounter, indicating a long-term effect on their vocal behaviour. This study demonstrates that gibbons discriminate between different potential predators and respond to them with adaptive anti-predator behaviour, which include predator-specific vocal responses. We conclude that gibbons are not immune to predation and that terrestrial predators elicit consistent immediate and delayed anti-predation responses.  相似文献   
104.
The atomised nature of the humanitarian system has led to frequent and repeated attempts to coordinate humanitarian activity. Since 2005, some of the best resourced, and arguably most successful, coordination mechanisms have been the humanitarian Clusters, groups of UN (United Nations) and non‐UN actors that engage in sectoral coordination of humanitarian response (such as the provision of healthcare and water) at the global and country level. Nevertheless, it is not clear exactly what ‘coordination’ means in the context of a Cluster. Formal guidance suggests that they should be aiming to create a single, joint strategy to guide the activities of members. Actual experience of the Clusters, however, indicates that looser forms of coordination are more effective. This finding resonates with organisational theory, and with the experience of emergency management professionals beyond the international humanitarian sector. To capitalise fully on the success of the Clusters, policymakers may need to rethink their attitudes to, and expectations of, coordination.  相似文献   
105.
Dune slack habitats are highly dependent on the availability of water to support flora and fauna. Typically this is provided by shallow groundwater. This paper describes the seasonal and long term variation in groundwater levels in part of the Sefton coastline between 1972 and 2007. The effects of climate change, vegetation management and coastline realignment on groundwater levels are modelled. The observed annual water table levels rise and fall with an amplitude of 1.5 m, but longer term variations and trends are apparent. A stochastic water balance model was used to describe the changes in water table levels in slack floors in the open dunes and also in areas afforested with pine trees. It was found that the pine trees evaporated 214 mm/year more than open dunes vegetation, resulting in the water table being 0.5–1.0 m lower under the trees than under the open dunes. The effects of climate change on the ground water was simulated using predictions of future climate conditions based on the UKCIP02 medium high emissions scenario. The increase in temperature and change in rainfall patterns will result in a decrease in mean ground water levels by 1.0–1.5 mm in the next 90 years. Typical patterns consist of sequences of 5–10 years of low water table levels interspersed by infrequent sequences consisting of 2–5 years of relatively high or “normal” levels. These results indicate that that flora and fauna that cannot survive a 5–10 year period of water table levels >2.5 m below ground level are unlikely to survive or persist in many slack areas and a change in the ecology of these slack may become inevitable. Other effects of climate change include sea level rise which will result in a gradual rise in water table levels. Coastal erosion will increase the water table gradient to the sea and result in a slight lowering of the ground water levels. Conversely coastal accretion will reverse this process. The spatial distribution of coastal erosion and accretion along the Sefton coastline and its likely impacts on groundwater levels are discussed. The modelling work described in this paper has identified the factors which have the largest effect on groundwater levels in temperate coastal dune systems.  相似文献   
106.
This paper considers the stability of public responses to an urban river restoration scheme on the River Skerne, Darlington, UK, by comparing the results from surveys of local residents carried out before and after scheme implementation. This case study provides evidence of strong and generally consistent positive responses to the proposals and implemented scheme to return the straightened and channelized river to a more natural condition although support was more qualified after than before implementation. Although the scheme design and construction costs were high, nearly two-thirds regarded the scheme as value for money. Exploratory contingent valuation results on whether or not local residents were prepared to pay for the scheme were broadly stable over the two surveys.  相似文献   
107.
Plant and soil bio(chemical) indicators are increasingly used to provide information on N deposition inputs and effects in a wide range of ecosystem types. However, many factors, including climate and site management history, have the potential to influence bioindicator relationships with N due to nutrient export and changing vegetation nutrient demands. We surveyed 33 heathlands in England, along a gradient of background N deposition (7.2–24.5 kg ha−1 year−1), using Calluna vulgaris growth phase as a proxy for time since last management. Our survey confirmed soil nutrient accumulation with increasing time since management. Foliar N and phosphorus (P) concentrations in pioneer- and mature-phase vegetation significantly increased with N deposition. Significant interactions between climate and N deposition were also evident with, for example, higher foliar P concentrations in pioneer-phase vegetation at sites with higher temperatures and N deposition rates. Although oxidized N appeared more significant than reduced N, overall there were more, stronger relationships with total N deposition; suggesting efforts to control all emissions of N (i.e., both oxidized and reduced forms) will have ecological benefits.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0529-4) contains supplementary material, which is available to authorized users.  相似文献   
108.
A map of summer total phosphorus in lakes has been compiled for Minnesota, Wisconsin, and Michigan to clarify regional patterns in attainable lake trophic state. Total phosphorus was used as a measure of lake trophic state because: (1) phosphorus plays a central role in controlling the overall fertility of most lakes, (2) total phosphorus values are available for a great number of lakes, and (3) phosphorus is measured in a consistent manner. The maps were compiled using patterns of total phosphorus data and observed associations between these data and geographic characteristics including physiography, land use, geology, and soils. Regions depicted on the map represent areas of similarity in phosphorus concentrations in lakes, or similarity in the mosaic of values, as compared to adjacent areas. Within each region, differences in total phosphorus can be compared to natural and anthropogenic factors to determine the types of lakes representative of each region, the factors associated with differences in quality, and the realistically attainable phosphorus levels for each type of lake.  相似文献   
109.
The yields of eleven commercially grown soybean cultivars were compared in ethylenediurea (EDU)-treated and non-treated field plots in New Brunswick, New Jersey, over a 4 year period. No statistically significant difference between treatments was found for any cultivar; the inference being ambient ozone did not adversely affect soybean yield. Succeeding field experiments supported this interpretation of the data. 'Sanilac' white bean, a legume known to be more sensitive to O(3) than soybean, was found to produce a significantly greater yield in EDU-treated than non-treated plots, unlike a companion planting of 'Williams 82' soybean which did not exhibit the differential response. The results indicated that the specific EDU protocol used in the soybean experiments is capable of detecting an ozone effect in a legume. Moreover, in a concurrent greenhouse experiment the yield of EDU-treated Sanilac white bean was not significantly different from non-treated plants in the absence of ozone pollution. In a dose-response field experiment during a year of unusually high O(3) pollution, yield of 'Williams 82' increased slightly with each EDU increment up to 500 ppm and decreased at 1000 ppm. The difference between non-treated and EDU-treated plants, however, was not statistically significant. There was no evidence to suggest that the EDU concentration (500 ppm) used in previous soybean experiments reduced seed yield. Fortuitously, the tolerance of commercially-grown soybean to ambient ozone is at least partially conditioned by the practce of not irrigating the crop. The New Jersey results are in agreement with reports from Maryland, Georgia and Tennessee in which an adverse impact of ambient O(3) was not found in soybean, but contrary to a current predictive model.  相似文献   
110.
Native freshwater faunas in North America are declining, principally due to the combined effects of habitat degradation and introduced species. Relatively little attention has been directed to the decline of freshwater invertebrates, which may be even more threatened than fishes. This paper chronicles recent changes in the distribution and abundance of the Shasta crayfish ( Pacifastacus fortis Faxon), a state and federally endangered species endemic to the midreaches of the Pit River system in northeastern California. We made snorkeling and SCUBA surveys for crayfish in 1990 and 1991 and examined various records for historic distributions. Shasta crayfish have been extirpated from much of their historic range by water impoundment and diversion, and they are further threatened by two introduced crayfish species ( Pacifastacus leniusculus Dana and Orconectes virilis Hagen). By 1990 Shasta crayfish were restricted to seven isolated populations, mostly in the headwaters of spring-fed tributaries to the Pit river. P. leniusculus had become established throughout much of the study area in about 12 years. In one site P. leniusculus probably contributed to the precipitous decline of Shasta crayfish, from 2000–3000 in 1980 to about 370 (± 135) in 1991. O. virilis , which occurred in only the most disturbed parts of the system, showed little range expansion in 30 years and had been replaced in a large stretch of the Pit River by P. leniusculus. P. leniusculus occupied sites with a broad range of habitat variables (temperature, pH, turbidity, substrate size) partly or wholly overlapping measures of sites with the other two species. The decline of the Shasta crayfish, like the extinction of its closest relative P. nigrescens in the San Francisco Bay area earlier this century, reflects the decline of its habitat and probably pressure from the aggressive exotic P. leniusculus .  相似文献   
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