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701.
Dr. M. V. Angel 《The Environmentalist》1982,2(1-2):1-17
Considerable concern has been recently expressed in conservation circles about the potential threat to oceanic trench ecosystems.
Here, the geological origin in environmental characteristics and biological significance of the trenches are reviewed.
Each trench provides a unique and isolated habitat, consequently endemicity has been found to be high at the specific level
in each trench that has been adequately studied. However, the remoteness from primary food sources greatly reduces the richness
of the fauna.
The physical instability of trench habitats deriving from their high level of seismic activity, will result in the organisms
being pre-adapted to mechanical disturbance. The main threats are either direct through poisoning by toxic chemicals or indirect
through the decoupling of the trench habitat from its primary food source, or reduction in oxygen levels caused either by
eutrophication or reduction in flushing rates.
Only direct threats are considered as being at all dangerous, and any incident would be restricted to a single trench system.
these threats could be reduced by rerouting vessels carrying toxic cargoes and by improving the effectiveness of the London
Dumping Convention.
The internationally agreed criteria for the selection of sites for any proposed seabed disposal of radioactive waste exclude
the use of trenches for this purpose. 相似文献
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The objective of this study was to assess the effects of two brief training interventions to improve obstetricians' and midwives' explanations to patients of a routine prenatal screening test. Health professionals were randomly allocated to one of two intervention groups or a control group. Information-giving about the test and communication skills were assessed at baseline, post-training and 3-month follow-up from audiotaped consultations. Both intervention groups received a 1-h training session involving small group discussions focused around a video. In addition, one group received individual feedback on their baseline and post-training consultations. Twenty-six midwives and nine obstetricians completed the study according to the protocol. Changes between baseline and post-training, and between baseline and follow-up, were computed. Information-giving and communication skills improved significantly in subjects receiving training and feedback on their performance, with the greatest improvements occurring before feedback was given. Those receiving training without feedback significantly improved their communication skills and showed some improvement in information-giving. These results show that modest improvements in communication can be made with relatively brief training. Greater and more sustained improvements may be found if all staff were trained, and trained on a regular basis. 相似文献
708.
Dr. R. Harold Holbrook Jr Ann M. Krovoza Susan Schelley James E. Ferguson II 《黑龙江环境通报》1987,7(9):653-655
Anencephaly in twin B was accompanied by elevated amniotic fluid alpha-fetoprotein (AFP) and a positive acetylcholinesterase (AChE) band on gel electrophoresis in both twin sacs, although twin A was normal. AChE results did not help distinguish the false positive AFP in this set of twins, implying that AChE may diffuse transamniotically as has been previously postulated for AFP. In light of the low concordance rate for neural tube defects in twins, patient counselling in this situation must include the information that AFP and AChE may be falsely elevated in normal twin when the other twin has a neural tube defect. 相似文献
709.
Dr Ingo Kennerknecht Sabine Krämer Dieter Grab Rainer Terinde Walther Vogel 《黑龙江环境通报》1993,13(4):257-269
Data in the literature suggest that confined placental mosaicism might be associated with intrauterine growth retardation. However, this association may be coincidental and due to bias of ascertainment. We therefore started a prospective study based on the cytogenetic evaluation of placentae derived from growth-retarded newborns. We further minimized possible bias by excluding those small-for-date infants displaying findings which already could explain intrauterine growth retardation (mothers who are smokers, multiple pregnancies, gestosis, dysmorphic infants). In a collection of 71 small-for-gestational age newborns, we did not see a single case of true confined placental mosaicism. 相似文献
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