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41.
Rowe EC Williamson JC Jones DL Holliman P Healey JR 《Journal of environmental quality》2005,34(3):994-1003
Pocket planting reclamation techniques developed in the 1970s for revegetating blocky quarrying waste have met with very limited success, often because the low water-holding capacity of the waste and limited root development within a small volume of planting pocket material result in severe drought mortality. We tested pocket planting approaches for waste tip reclamation at Europe's largest slate quarry, and compared materials for enhancing the continuity of water- and nutrient-holding down into the interior of the waste tip. When small compost-filled pocket planting bags were placed above slate processing fines (SPF) or water absorbent cross-linked polyacrylamide gel ("hydrogel"), tree growth rates increased in comparison with pocket planting bags alone. The SPF significantly improved tree survival especially during severe drought, but survival was not enhanced by the use of hydrogel. The sorption characteristics of hydrogel indicated that its presence may help to reduce nutrient leaching, but that it may have a negative effect on nitrogen availability. A more likely explanation for the poor performance of pure hydrogel is that it did not maintain sufficient available water, because of discontinuities caused by shrinkage and movement of the hydrogel, and/or degradation of water-holding capacity with environmental exposure. However, the root growth observed in the hydrogel treatments suggests that this technique, if adapted to reduce the effects of hydrogel shrinkage by using finer-grade hydrogel, mixing it with other soil-forming material, and reducing its exposure to extremes of temperature or sunlight, might have the potential to improve the growth and survival of trees planted on sites where delivery of heavy materials such as SPF is impractical. Fine mineral processing waste is freely available at active quarries and should be seen as a key resource for reclamation schemes. 相似文献
42.
Profile of persistent chlorinated contaminants,including selected chiral compounds,in wolverine (Gulo gulo) livers from the Canadian Arctic 总被引:2,自引:0,他引:2
Wolverines (Gulo gulo) are circumpolar omnivores that live throughout the alpine and arctic tundra ecosystem. Wolverine livers were collected at Kugluktuk (Coppermine), NU (n=12) in the western Canadian Arctic to report, for the first time, the residue patterns of persistent organochlorine contaminants (OCs) in this species. The enantiomer fractions (EFs) of several chiral OCs, including PCB atropisomers, in wolverines were also determined. Results were compared to OC concentrations and EFs of chiral contaminants in arctic fox (Alopex lagopus) from Ulukhaqtuuq (Holman), NT (n=20); a closely related species that scavenges the marine and terrestrial arctic environment. The rank order of hepatic concentrations for sum ( summation operator ) OC groups in wolverines were polychlorinated biphenyls ( summation operator PCB)>chlordane-related components ( summation operator CHLOR)>DDT-related compounds ( summation operator DDT)>hexachlorocyclohexane isomers ( summation operator HCHs). The most abundant OC analytes detected in wolverine liver were PCB-153, PCB-180, and oxychlordane (OXY). Wolverine age and gender did not influence OC concentrations, which were comparable to lipid-normalized values in arctic fox. The EFs of several chiral OCs (alpha-HCH, cis- and trans-chlordane, OXY, heptachlor exo-epoxide) and PCB atropisomers (PCB-136, 149) were nonracemic in arctic fox and wolverine liver and similar to those previously calculated in arctic fox and polar bears from Iceland and the Canadian Arctic. Results suggest that these species have similar ability to biotransform OCs. As well, contaminant profiles suggest that terrestrial mammals do not represent the major source of OC exposure to wolverines and that wolverines are scavenging more contaminated prey items, such as marine mammals. While summation operator PCB did not exceed the concentrations associated with mammalian reproductive impairment, future research is required to properly evaluate the potential affect of other OCs on the overall health of wolverines. 相似文献
43.
44.
Transgenerational isotope labelling (TRAIL) using enriched stable isotopes provides a novel means of mass-marking marine fish
larvae and estimating larval dispersal. The technique, therefore, provides a new way of addressing questions about demographic
population connectivity and larval export from no-take marine protected areas. However, successful field applications must
be preceded by larval rearing studies that validate the geochemical marking technique, determine appropriate concentrations
and demonstrate that larvae are not adversely affected. Here, we test whether injection of enriched stable barium isotopes
(135Ba and 137Ba) at two dose rates produces unequivocal marks on the otoliths of the coral reef grouper Epinephelus fuscoguttatus. We also assess potential negative effects on reproductive performance, egg size, condition and larval growth due to injection
of adult female fish. The injection of barium isotopes at both 0.5 and 2.0 mg Ba/kg body weight into the body cavities of
gravid female fish was 100% successful in the geochemical tagging of the otoliths of larvae from the first spawning after
injection. The low-dose rate produced no negative effects on eggs or larvae. However, the higher dose rate of 2 mg Ba/kg produced
small reductions in yolk sac area, oil globule area, standard length and head depth of pre-feeding larvae. Given the success
of the 0.5 mg Ba/kg dose rate, it is clearly possible to produce a reliable mark and keep the concentration below any level
that could affect larval growth or survival. Hence, enriched Ba isotope injections will provide an effective means of mass-marking
grouper larvae. 相似文献
45.
Fetal nucleated red blood cells (n-rbc) occur in the maternal circulation from 7 weeks of pregnancy. The enrichment of these cells from maternal blood will depend upon their stage of differentiation, which changes during development. We characterised the fetal n-rbc from chorionic villus sample (CVS) washings and used them to model first trimester non-invasive prenatal diagnosis. The ratio of ε- to γ-globin-producing cells declined rapidly from 10 to 13 weeks, as did the ratio of nucleated to non-nucleated rbc. By 13 weeks the great majority of cells containing γ- or ε-globin are anucleate. The fetal n-rbc were highly variable in size and density and sedimented over a wide density range with a high proportion (>80%) at a density overlapping with that of maternal rbc. We have devised an enrichment procedure using Orskoff lysis to differentially lyse the maternal cells followed by density centrifugation and separation using magnetic beads. This simple protocol allowed recovery of 70% (69±22%) of fetal cells when added at approximately 10 fetal cells/ml maternal blood. When 1 fetal cell/ml millilitre maternal blood was added (total volume 10 ml) the recovery was more variable but remained at approximately 70% (72±47%), with at least one fetal cell recovered in all cases. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
46.
C. J. Williamson J. Brodie B. Goss M. Yallop S. Lee R. Perkins 《Marine Biology》2014,161(9):2051-2068
The photophysiology of three geniculate coralline algal species (Corallina officinalis, C. caespitosa and Ellisolandia elongata) was determined in intertidal rock pools in the south-west UK at Combe Martin (51°12′31N 4°2′19W) and Heybrook Bay (50°31′66N 4°11′41W), at the start, middle and end of summer (September 1 and 2) and winter (February 9 and 10) daylight tidal emersion periods, in relation to prevailing irradiance, temperature and carbonate chemistry conditions. Algal photophysiology was assessed from rapid light curves performed using pulse amplitude modulation fluorometry. Corallina and Ellisolandia experienced significant fluctuations in irradiance, temperature and carbonate chemistry over seasonal and tidal cycles. Rock pool carbonate chemistry was predictable (R 2 = 0.82, P < 0.0001) by photodose (summed irradiance) plus water temperature, but not significantly related to photophysiology. In contrast, Corallina and Ellisolandia relative maximum electron transfer rate showed a significant negative relationship (R 2 = 0.65, P < 0.0001) with irradiance plus water temperature. At a seasonal resolution, photoacclimation to maximize both light harvesting during winter months and photoprotection during summer months was observed for all species. Dynamic photoinhibition was apparent over both summer and winter tidal emersion, in relation to irradiance fluctuations. More effective photoinhibition was apparent during summer months, with greater sensitivity to irradiance and slower recovery in F v/F m, observed during winter. With sustained high irradiance over tidal emersion, the establishment of high pH/low inorganic carbon conditions may impact photochemistry. This study represents the first assessment of C. officinalis, C. caespitosa and E. elongata photophysiology underpinned by clear species concepts and highlights their ability to adapt to the dramatically fluctuating conditions experienced in intertidal rock pools. 相似文献
47.
The woolscouring (wool washing) industry has traditionally been viewed as highly polluting and, consequently, effluent treatment systems have been sought. The first stage in the current treatment system for woolscour wastewater, a chemical flocculation process (Sirolan CF), creates a sludge composed of soil and wool grease. We investigated the chemical and biological characteristics of this sludge. The sludge was found to be highly variable on a day to day basis in terms of its chemical composition and biodegradability; 0.8 to 27.8% of sludge total nitrogen was mineralized over 30 d at 37 degrees C. The grease component of sludge (14-40% on a dry weight basis) may retard the decomposition of the sludge but the polyacrylamide flocculant used in its production and its pesticide content had no effect on the rate of decomposition. Our results suggest that variability in substrate quality may translate into variability in treatment performance and have important implications for the biological treatment of industrial wastes, including composting. 相似文献
48.
The concentrations of Fe, Mn, Zn, Cr, Cu, Pb, Ni, Cd, and Ag were determined in soft tissue and shell material of mussel Mytilus edulis collected in the winter season from five coastal sites in the northeast of England. The trace metal levels observed were significantly high, particularly at locations affected by past coal mining activities (Blackhall) and present industrial sources (Middleton). The mussels from the chosen control site (Holy Island), a shellfish-designated area, were particularly enriched in Cu and Ag. The metal pollution index for the Bran Sands site, a heavily industrialised area on the Tees Estuary, was relatively low. At four sites out of five, the levels of Fe and Cu were negatively correlated with mussel size. No significant correlation with size was found for the other metals. With few exceptions, the elements Fe, Zn, and Mn accumulated preferentially in the soft tissue, whereas Pb, Cd, Cr, Ag, and Ni were more abundant in the hard part of the mussels. The Ag values in shell material were remarkably similar (about 6 mg kg−1 – 7 mg kg−1, dry wt) at all sites studied. In general, the data show that the mussels from the coastline studied accumulate metal concentrations comparable to or higher than the most contaminated sites reported in the literature. 相似文献
49.
We used a longitudinal design to examine the predictors of early career research productivity for 152 management professors over the first six years of their career. Results revealed early career research productivity to be a function of dissertation advisor research productivity, pre‐appointment research productivity, and the research output of a faculty member's academic origin and academic placement. However, the effects of these predictors varied over time in terms of strength. The findings are discussed in terms of guiding the evaluation and hiring of new researchers in knowledge‐based industries. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
50.
The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky
Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the
Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico. Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid
from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei. Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the
postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth.
Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form
seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes. 相似文献