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371.
The Macrouridae are the most common fish caught in demersal trawls on the continental slope and rise of the Rockall Trough. They represented 41% of all fish caught, with Coryphaenoides rupestris amounting to 28% of the catch. No previous study of the trophic interaction of these fish has been made over a wide bathymetric range. Samples were obtained at 250-m intervals of depth between 400 and 2 900 m in the period 1975 to 1981. The stomachs of 5 326 fish belonging to 12 species were examined to define their diets. Eight species are primarily benthopelagic feeders while four are primarily epibenthic feeders. The bathymetric centres of distribution of the populations of the benthopelagic feeding Trachyrhynchus murrayi, Malacocephalus laevis, Coryphaenoides rupestis, C. guentheri, Nematonurus armatus, Chalinura brevibarbis, C. leptolepis and C. mediterranea are different from each other. Similar differences in bathymetric distribution occurred among the epibenthic feeding Nezumia aequalis, Coelorhynchus coelorhynchus, C. occa and Lionurus carapinus. These differences decrease competition among species that exploit similar resources. 相似文献
372.
S. H. Imam S. H. Gordon A. Burgess-Cassler R. V. Greene 《Journal of Polymers and the Environment》1995,3(2):107-113
Most of the starch in starch-polyethylene-co-acrylic acid (EAA)-polyethylene (PE) composites prepared by injection molding was not accessible to starch-hydrolyzing enzymes. Even when these composites were treated with enzyme in the presence of Triton X-100 for 96 h, little starch hydrolysis was observed. However, when the starch-plastic material was pulverized, both the extent and the rate of starch hydrolysis increased dramatically, with about 70% hydrolysis of the starch within 18 h. Reactions carried out for up to 96 h showed that, while the enzyme was active, the reaction reached a plateau, achieving a total of 80% starch hydrolysis. Fourier transform infrared (FTIR) spectroscopy revealed that only starch, and not EAA or PE, was affected by enzyme in pulverized samples. Results indicated that while 80% of the starch in these composites was transiently inaccessible, perhaps due to EAA and PE forming an impermeable barrier to the enzyme, the other 20% remained inaccessible to enzymes. Also, the rate of starch digestion as determined by solubilized reducing sugar correlated with the particle size of the pulverized material, suggesting that a large available surface area is critical for rapid starch degradation in such composites.The mention of firms names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over the firms or similar products not mentioned. All programs and services of the U.S. Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, marital status, or handicap. 相似文献
373.
374.
Bashar J. Alhajjar C. Linn Gould Gordon Chesters John M. Harkin 《Journal of contaminant hydrology》1990,6(4)
The effects of phosphate (P) and zeolite (Z) -built detergents on leaching of N and P through sand columns simulating septic system drainfields were examined in laboratory columns. To simulate mound septic system drainfields, paired sets of columns were dosed intermittently with septic tank effluent from households using P- or Z-built detergent. Two other paired sets of columns were flooded with P- or Z-effluent to simulate new conventional septic system drainfields; after clogging mats or “crusts” developed at infiltration surface, the subsurfaces of the columns were aerated to simulate mature (crusted) conventional septic system drainfields. NO3 loading in leachate was 1.1 times higher and ortho-P loading was 4.3 times lower when columns were dosed with Z- than with P-effluent. Dosed columns removed P poorly; total phosphorus (TP) loading in leachate was 81 and 19 g m−2 yr−1 with P- and Z-effluent, respectively. In flooded columns 1.3, 2.0 and 1.8 times more NH4, organic nitrogen (ON) and total nitrogen (TN) respectively, were leached with Z- than with P-effluent; NO3 leaching was similar. Flooded columns removed P efficiently; TP leached through flooded systems was 2.5 and 1.4 g m−2 yr−1 with P- and Z effluent, respectively. Crusted columns fed Z-effluent leached 1.2, 2.6, 1.4 and 2.1 times more NH4, NO3, ON and TN, respectively, than those with P-effluent but 1.8 times less TP. Crusted columns removed P satisfactorily: 8.2 and 4.6 g m−2 yr−1 TP with P- and Z-effluent, respectively. The P-built detergent substantially improves the efficiency of N removal with satisfactory P removal in columns simulating conventional septic system drainfield. Simultaneous removal of N and P under flooded conditions might be explained by precipitation of struvite-type minerals. Dosed system drainfields were less efficient in removing N and P compared to flooded and crusted system drainfelds. 相似文献
375.
Gordon W Alker 《Journal of Environmental Planning and Management》1995,38(4):469-482
Environmental monitoring activities are examined from a perspective which focuses on the political, economic and social factors which shape what we know and do not know about local environments. A UK urban case study is used to examine the range of influences that can operate on local level monitoring and comparisons are then made with the situation in three other European cities. Conclusions are drawn which debate the appropriate balance between local discretion and national and international direction in the collection of environmental information. It is argued that scrutiny of and revisions to the quality of current environmental monitoring in the UK and wider debate over questions of purpose, scope and resource commitment are needed. 相似文献
376.
Estimating Relevance of Organic Carbon,Nitrogen, and Phosphorus Loads to a Blackwater River Estuary1
John Hendrickson Nadine Trahan Emily Gordon Ying Ouyang 《Journal of the American Water Resources Association》2007,43(1):264-279
Abstract: In blackwater river estuaries, a large portion of external carbon, nitrogen, and phosphorus load are combined in complex organic molecules of varying recalcitrance. Determining their lability is essential to establishing the relationship between anthropogenic loads and eutrophication. A method is proposed in which organic C, N, and P are partitioned into labile and refractory forms, based upon first‐order decay estimated by biochemical oxygen demand relative to total organic carbon, and C:N and C:P ratios as a function of organic carbon lability. The technique was applied in developing total maximum daily loads for the lower St. Johns, a blackwater Atlantic coastal plain river estuary in Northeast Florida. Point source organic nutrients were determined to be largely labile. Urban runoff was found to have the highest relative labile organic N and P content, followed by agricultural runoff. Natural forest and silviculture runoff were high in refractory organic N and P. Upstream labile C, N, and P loads were controlled by autochthonous production, with 34‐50% of summer total labile carbon imported as algal biomass. Differentiation of labile and refractory organic forms suggests that while anthropogenic nutrient enrichment has tripled the total nitrogen load, it has resulted in a 6.7‐fold increase in total labile nitrogen load. 相似文献
377.
Since the announcement by Fleischmann and Pons that the excess enthalpy generated in the negatively polarized Pd–D-D2O system was attributable to nuclear reactions occurring inside the Pd lattice, there have been reports of other manifestations
of nuclear activities in this system. In particular, there have been reports of tritium and helium-4 production; emission
of energetic particles, gamma or X-rays, and neutrons; as well as the transmutation of elements. In this communication, the
results of Pd–D co-deposition experiments conducted with the cathode in close contact with CR-39, a solid-state nuclear etch
detector, are reported. Among the solitary tracks due to individual energetic particles, triple tracks are observed. Microscopic
examination of the bottom of the triple track pit shows that the three lobes of the track are splitting apart from a center
point. The presence of three α-particle tracks outgoing from a single point is diagnostic of the 12C(n,n′)3α carbon breakup reaction and suggests that DT reactions that produce ≥9.6 MeV neutrons are occurring inside the Pd
lattice. To our knowledge, this is the first report of the production of energetic (≥9.6 MeV) neutrons in the Pd–D system.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
378.
Clive?BonsallEmail author Adina?Boronean? Andrei?Soficaru Kathleen?McSweeney Tom?Higham Nicolae?Miri?oiu Catriona?Pickard Gordon?Cook 《Die Naturwissenschaften》2012,99(4):321-325
In 1968, excavations in the Climente II cave in the Iron Gates gorge of the River Danube in southwest Romania unearthed the skeleton of an adult male. The burial was assumed to be of Late Pleistocene age because of the presence of Late Upper Palaeolithic (LUP) artefacts in the cave. However, there was no strong supporting stratigraphic evidence, and the body position is reminiscent of Early Neolithic burial practice in the region. Here, we report the results of radiocarbon and stable isotope analyses of the Climente II skeleton, which show that the skeleton dates to the Bølling–Allerød Interstadial ~14,500 cal BP. This is several millennia older than any previously dated human remains from the Iron Gates region and confirms its status as the oldest known burial from Romania. The stable isotope results indicate a diet with an emphasis on aquatic resources, contrary to the commonly held view that the LUP inhabitants of the Iron Gates subsisted mainly by hunting large land mammals. 相似文献
379.
Luke D. Bainard Alexander M. KochAndrew M. Gordon Steven G. NewmasterNaresh V. Thevathasan John N. Klironomos 《Agriculture, ecosystems & environment》2011,144(1):13-20
Tree-based intercropping (TBI) is an ecologically sustainable agricultural practice that may promote a more diverse arbuscular mycorrhizal (AM) fungal community compared to conventional systems, but the influence of the dynamics of these systems on AM fungi has not been established. Soil and root samples were collected in the intercropping alleys along transects perpendicular to tree rows occupied by white ash (Fraxinus americana), poplar (Populus deltoids × nigra), Norway spruce (Picea abies), and rows without trees (control). Molecular analysis of the AM fungal community at the TBI site revealed 17 phylotypes belonging to the Glomeraceae. Overall, the AM fungal community in the TBI site was comparable to other conventional agricultural systems; with the majority of phylotypes belonging to Glomus group A. AM fungal phylotype richness and community composition significantly differed among the treatments in the TBI site. AM fungal communities were more diverse in cropping alleys adjacent to trees that associate with AM fungi than trees that do not associate with AM fungi. Norway spruce had a negative influence on the AM fungal community as tree rows and bordering intercropping alleys had a significantly lower phylotype richness and different community composition. These results suggest that to maintain a diverse AM fungal community throughout TBI systems, it may be best to incorporate tree species that associate with AM fungi. 相似文献
380.
Christian Kuhlicke Annett Steinführer Chloe Begg Chiara Bianchizza Michael Bründl Matthias Buchecker Bruna De Marchi Marina Di Masso Tarditti Corina Höppner Bla? Komac Louis Lemkow Jochen Luther Simon McCarthy Luigi Pellizzoni Ortwin Renn Anna Scolobig Meera Supramaniam Sue Tapsell Gisela Wachinger Gordon Walker Rebecca Whittle Matija Zorn Hazel Faulkner 《Environmental Science & Policy》2011,14(7):804-814
Social capacity building for natural hazards is a topic increasingly gaining relevance not only for so-called developing countries but also for European welfare states which are continuously challenged by the social, economic and ecological impacts of natural hazards. Following an outline of recent governance changes with regard to natural hazards, we develop a heuristic model of social capacity building by taking into account a wide range of existing expertise from different fields of research. Particular attention is paid to social vulnerability and its assessment, as well as to risk communication and risk education as specific strategies of social capacity building. We propose to distinguish between interventionist and participatory approaches, thus enabling for a better understanding of existing practices of social capacity building as well as their particular strengths and weaknesses. By way of conclusion, we encourage more research on social capacity building for natural hazards in the European context which at present is highly diverse and, at least in parts, only poorly investigated. 相似文献