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排序方式: 共有248条查询结果,搜索用时 15 毫秒
11.
Ann Vanreusel Magda Vincx Danielle Schram Dirk van Gansbeke 《International Review of Hydrobiology》1995,80(2):313-326
The metazoan meiofauna of nine stations in shelf break and upper slope areas (70 to 1500 m water depth) of the N.E. Atlantic were investigated in order to assess which environmental factors are important in the control of densities and sediment profiles. Total meiofaunal densities (ranging between 368 and 1523 ind/10 cm2) were correlated with bacterial densities, an important food source for meiofauna. However, considering sediment vertical distribution profiles, the relative importance of both food and oxygen on the meiofauna became obvious. A combination of both bacterial densities and oxygen supply could explain about 95% of the variability in the vertical profiles of the meiofauna densities. Meiofauna numbers increase in proportion to food availability in the surface sediment layers, but this relationship breaks down in deeper sediment layers where the oxygen supply is often limiting, particularly in fine sediments. 相似文献
12.
A Fusarium species with a micro morphology similar to F. poae and a metabolite profile resembling that of F. sporotrichioides has been identified. Like typical F. poae, the microconidia have a globose to pyriform shape, but the powdery appearance, especially on Czapek-Dox Iprodione Dichloran
agar (CZID), less aerial mycelium and the lack of fruity odour on Potato Sucrose Agar (PSA) make it different from F. poae. The lack of macroconidia, polyphialides and chlamydospores differentiates it from F. sporotrichioides. All 18 isolates investigated, 15 Norwegian, two Austrian and one Dutch, produced T-2 toxin (25–400 μg/g) on PSA or Yeast
Extract Sucrose agar (YES). In addition, neosolaniol, iso-neosolaniol, HT-2 toxin, 4- and 15-acetyl T-2 tetraol, T-2 triol
and T-2 tetraol and4,15-diacetoxyscirpenol were formed in variable amounts. Neither nivalenol, 4- or 15-acetylnivalenolor
4,15-diacetylnivalenol were detected in any of the cultures, while these toxins were produced at least in small amounts by
all the 12 typical F. poae isolates studied. The question of whether this Fusarium should be classified as F. poae or F. sporotrichioides or a separate taxon should be addressed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
E. Robert Thieler Bradford Butman Mead A. Allison Jeffrey P. Donnelly 《Palaeogeography, Palaeoclimatology, Palaeoecology》2007,246(1):120-136
The Hudson Shelf Valley (HSV) is the largest physiographic feature on the U.S. mid-Atlantic continental shelf. The 150-km long valley is the submerged extension of the ancestral Hudson River Valley that connects to the Hudson Canyon. Unlike other incised valleys on the mid-Atlantic shelf, it has not been infilled with sediment during the Holocene. Analyses of multibeam bathymetry, acoustic backscatter intensity, and high-resolution seismic reflection profiles reveal morphologic and stratigraphic evidence for a catastrophic meltwater flood event that formed the modern HSV. The valley and its distal deposits record a discrete flood event that carved 15-m high banks, formed a 120-km2 field of 3- to 6-m high bedforms, and deposited a subaqueous delta on the outer shelf. The HSV is inferred to have been carved initially by precipitation and meltwater runoff during the advance of the Laurentide Ice Sheet, and later by the drainage of early proglacial lakes through stable spillways. A flood resulting from the failure of the terminal moraine dam at the Narrows between Staten Island and Long Island, New York, allowed glacial lakes in the Hudson and Ontario basins to drain across the continental shelf. Water level changes in the Hudson River basin associated with the catastrophic drainage of glacial lakes Iroquois, Vermont, and Albany around 11,450 14C year BP (∼ 13,350 cal BP) may have precipitated dam failure at the Narrows. This 3200 km3 discharge of freshwater entered the North Atlantic proximal to the Gulf Stream and may have affected thermohaline circulation at the onset of the Intra-Allerød Cold Period. Based on bedform characteristics and fluvial morphology in the HSV, the maximum freshwater flux during the flood event is estimated to be ∼ 0.46 Sv for a duration of ∼ 80 days. 相似文献
14.
15.
To evaluate the dependence of the differentiation of the follicle-associated epithelium (FAE) on the presence of follicular B-cells, the FAE of ileal Peyers patch follicles was examined in B-cell-depleted fetal lambs. The FAE of these rudimentary follicles, which are devoid of lymphocytes, showed normal differentiation, including carbonic anhydrase reactivity and ultrastructural characteristics of transcytosis, extensive interdigitation of the lateral plasma membrane and the shedding of membrane-bounded particles, approximately 50 nm in size, resembling exosomes. These 50-nm membrane-bounded particles were abundant in the extracellular space of the epithelium and the dome but no particles were found in the rudimentary follicles. This study confirms that the rudimentary follicles consist of clusters of follicular dendritic cells. Our findings suggest that the differentiation of FAE of ileal Peyers patch and the production of the 50-nm particles constitute features that appear to be independent of B-cells. This study was supported in part by grants from the Norwegian Research Council 相似文献
16.
Environmental Impacts of Wild Caught Cod and Farmed Salmon - A Comparison with Chicken (7 pp) 总被引:1,自引:0,他引:1
Harald Ellingsen Svein Aanond Aanondsen 《The International Journal of Life Cycle Assessment》2006,11(1):60-65
Goal, Scope and Background The objective of this study was to assess environmental impacts of Norwegian cod fishing and salmon farming and compare these
with chicken farming in order to find reference levels for environmental performance and identify problem areas and potentials
for improvements.
Methods A Life Cycle Screening following the production of 0.2 kg fillets as a functional unit through the respective food chains
is performed for all 3 products. The analysis is partly quantitative and qualitative focusing on energy use, antifouling and
land use impacts. Case studies are performed to investigate potentials for improvements within the fisheries and aquaculture
industry.
Results and Conclusions It can be concluded that the fishing phase for the cod and the feeding phase for both salmon and chicken dominate for all
environmental impacts considered. Chicken is most energy effective followed by salmon and cod, which are almost on the same
level. The area of sea floor affected by bottom trawling is around 100 times larger than the land area needed to produce the
chicken feed for production of the 0.2 kg fillet.
- The case studies show potentials for improvement of environmental performance, both for salmon farming and cod fishing, especially
when it comes to energy use. The environmental impacts on the sea floor imposed by bottom trawling are not fully explored,
but based on the precautionary principle a reasonable conclusion is that bottom trawls with less impact on the sea floor should
be developed.
Recommendation and Perspective LCA methods have initially been developed for land based industrial applications. More effort should be given to adapt these
to fishing applications in order to obtain more accurate assessment of environmental impacts from seafood products. It is
recommended to put more emphasis in finding improved indicators for impacts imposed by over-fishing, fuel emission from combustion
at sea, use of antifouling and seafloor ecosystem disturbance. 相似文献
17.
Yánez-Mendizábal V Viñas I Usall J Torres R Solsona C Abadias M Teixidó N 《Journal of applied microbiology》2012,112(5):954-965
Aims: To prepare commercially acceptable formulations of Bacillus subtilis CPA‐8 by spray‐drying with long storage life and retained efficacy to control peach and nectarine brown rot caused by Monilinia spp. Methods and Results: CPA‐8 24‐h‐ and 72‐h‐old cultures were spray dried using 10% skimmed milk, 10% skimmed milk plus 10% MgSO4, 10% MgSO4 and 20% MgSO4 as carriers/protectants. All carriers/protectants gave good percentages of powder recovery (28–38%) and moisture content (7–13%). CPA‐8 survival varied considerably among spray‐dried 24‐h‐ and 72‐h‐old cultures. Seventy‐two hours culture spray dried formulations showed the highest survival (28–32%) with final concentration products of 1·6–3·3 × 109 CFU g?1, while viability of 24‐h‐old formulations was lower than 1%. Spray‐dried 72‐h‐old formulations were selected to subsequent evaluation. Rehydration of cells with water provided a good recovery of CPA‐8 dried cells, similar to other complex rehydration media tested. Spray‐dried formulations stored at 4 ± 1 and 20 ± 1°C showed good shelf life during 6 months, and viability was maintained or slightly decreased by 0·2–0·3‐log. CPA‐8 formulations after 4‐ and 6 months storage were effective in controlling brown rot caused by Monilinia spp. on nectarines and peaches resulting in a 90–100% reduction in disease incidence. Conclusions: Stable and effective formulations of biocontrol agent B. subtilis CPA‐8 could be obtained by spray‐drying. Significance and Impact of the Study: New shelf‐stable and effective formulations of a biocontrol agent have been obtained by spray‐drying to control brown rot on peach. 相似文献
18.
Gil Rilov Sarah E. Dudas Brian A. Grantham Jane Lubchenco 《Journal of experimental marine biology and ecology》2008,361(2):59-74
The supply of larvae to the shore is important for population replenishment and intertidal community dynamics but its variability at most scales is not well understood. We tested the relationship between nearshore mussel larval abundance and intertidal settlement rates over several years at multiple spatiotemporal scales in Oregon and New Zealand. Abundance of competent larvae nearshore and intertidal recruitment rates were simultaneously quantified using collectors mounted at different depths on moorings 50-1100 m from shore, and at adjacent rocky intertidal sites. Total mussel larval abundance and oceanographic conditions were also measured in some locations. At all scales, abundance of nearshore mussel larvae was unrelated to intertidal recruitment rates. In the intertidal, patterns of mussel recruitment were persistent in space, with sites of consistently high or low recruitment. In contrast, nearshore competent larval abundance showed generally similar abundances among sites except for a high, and spatially-inconsistent, variability in Oregon during 1998 only. On moorings, recruitment tended to be greater on midwater collectors than shallower or deeper. Finally, on moorings larval abundance in traps and recruitment on collectors was unrelated. These results suggest that (1) among sites, the size of the nearshore larval pool is relatively uniform while onshore recruitment varies and is unrelated to larval abundance, (2) temporal variability in nearshore larval availability is not strongly expressed onshore, (3) vertical stratification of competent larvae nearshore is strong and may influence transport and recruitment, and (4) within-coast variability in onshore recruitment is strongly driven by processes occurring locally within the surf zone that need to be studied to understand coastal recruitment dynamics. 相似文献
19.
The effects of radiofrequency fields on human health are not well understood, and public concern about negative health effects has been rising. The aim of this study was to examine the relationship between workers exposed to electromagnetic fields and their reproductive health. We obtained data using a questionnaire in a cross-sectional study of naval military men, response rate 63% (n = 1487). We asked the respondents about exposure, lifestyle, reproductive health, previous diseases, work and education. An expert group categorized the work categories related to electromagnetic field exposure. We categorized the work categories "tele/communication," "electronics" and "radar/sonar" as being exposed to electromagnetic fields. Logistic regression adjusted for age, ever smoked, military education, and physical exercise at work showed increased risk of infertility among tele/communication odds ratio (OR = 1.72, 95% confidence interval 1.04-2.85), and radar/sonar odds ratio (OR = 2.28, 95% confidence interval 1.27-4.09). The electronics group had no increased risk. This study shows a possible relationship between exposure to radiofrequency fields during work with radiofrequency equipment and radar and reduced fertility. However, the results must be interpreted with caution. 相似文献
20.
G. R. Rodríguez L. Sequin G. R. Pratta R. Zorzoli L. A. Picardi 《Biologia Plantarum》2008,52(3):548-552
Pericarp polypeptide profiles were analyzed at three ripening stages in the F1 hybrid and the F2 population from the cross between the accessions: LA1385 (Lycopersicon esculentum var. cerasiforme) and 804627 (L. esculentum, a homozygous genotype for the nor mutant). Six polymorphic polypeptides were observed in LA1385, while no polymorphic polypeptides among ripening stages was
observed in 804627. On the other hand, some polypeptides in the F1 hybrid were not observed in the parents whereas others were present in both parental genotypes and were unnoticeable in the
hybrid genotype. From a cluster analysis on the protein profiles of the F2 population, the differential expression of proteins allowed to distinguish mature green (MG) stage from the others two stages,
while for breaker stage (BR) and red ripe stage, the genetic background was more important in forming groups. The differential
expression of proteins could be associated with fruit morphology traits such as a 72 kDa polypeptide present in MG stage with
fruit diameter, height and mass and a 47 kDa polypeptide found in BR with fruit shelf life. 相似文献