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791.
The value of using gamma glutamyl transferase (GT) to select amniotic fluids for karyotyping from patients at low risk of chromosome defects is assessed. This paper reports on 16 pregnancies with fetal trisomy 21 and compares these to two previous reports of GT in fetal trisomy 21. The value of GT is contrasted to the value of AFP in selecting liquors for karyotyping. 相似文献
792.
The exogenous application of chemical repellents is widespread in birds, but endogenous production is exceedingly rare. We herein report a new class of avian defensive compounds isolated from the feathers and volatile odor of the crested auklet (Aethia cristatella). Mass spectra indicate that n-hexanal, n-octanal, n-decanal, Z-4-decenal and a 12-carbon unsaturated aldehyde comprise the auklet odorant. Octanal and hexanal are also secreted in the repugnant metasternal gland emissions of heteropteran insects and are known to be potent invertebrate repellents. We suggest that the auklet odorant functions as an ectoparasite repellent and a signal of mate quality. This would represent a rare and direct link between vigor, quality and parasite resistance, one of several putative bases for mate selection. This is the first report of defensive compounds produced by a seabird or colonial bird and one of the few examples of chemical defense in a polar or subpolar marine vertebrate. 相似文献
793.
Duarte-Davidson R Wilson SC Jones KC 《Environmental pollution (Barking, Essex : 1987)》1994,84(1):79-87
Polychlorinated biphenyl (PCB) and SigmaDDT (i.e. p,p'-DDT + p,p'-DDE = p,p'-DDD) concentrations were determined from the analysis of 115 Welsh breast milk samples collected in 1990 and 1991. Fifty PCB congeners were screened, of which 24 were identified in most samples. The PCB congener pattern was consistent between individual milk samples, with IUPAC congeners 28, 138, 153 and 180 being the most abundant and accounting for an average of 50% of the SigmaPCB concentrations determined. PCB concentrations varied between 2 and 70 ng g(-1) whole milk, were positively correlated with age, and negatively correlated with the total lactation period and with the percent lipid content of the milk. PCB pattern distributions differed between milk and adipose tissue samples. Human milk had a higher proportion of tri- (18 and 28), tetra- (44, 52 and 66) and pentachlorinated biphenyls (101) compared to human adipose tissue. SigmaDDT concentrations ranged from 0.3 to 71 ng g(-1) of whole milk, with p,p'-DDE contributing towards an average of 92% of the SigmaDDT concentrations. SigmaDDT levels were also positively correlated with age and negatively associated with the lactation period, though these correlations were rather weak. No significant differences in the SigmaPCB and SigmaDDT concentrations were noted between milk samples from donors living in rural and urban locations, or between the subjects' body weight, smoking habits or diet. 相似文献
794.
Carrie Jones Carol Booth Debra Rita Lydia Jazmines Rhonda Spiro Brian McCulloch Christopher McCaskill Lisa G. Shaffer 《黑龙江环境通报》1995,15(9):843-848
We report a case of maternal uniparental disomy of chromosome 10 discovered after chorionic villus sampling (CVS). Direct preparations revealed mosaic trisomy 10, while cultured CVS cells, as well as amniotic fluid cells, showed only a normal 46,XY complement. DNA analysis using microsatellite markers showed both chromosomes 10 to have been inherited from the mother. The pregnancy was complicated by polyhydramnios. A phenotypically normal male infant of appropriate size was delivered by Caesarean section at 41 weeks' gestation. Since only the direct preparations showed trisomy 10, this case illustrates the importance of CVS direct preparations in the detection of pregnancies at risk of uniparental disomy (UPD). Although the increased frequency of confined placental mosaicism (CPM) diagnosed when direct preparations are performed has been viewed negatively, identification of both CPM and UPD may have biological and clinical significance for a pregnancy. Even though only a single case of maternal disomy 10 is reported here, the apparently normal phenotype provides evidence that there are no major imprinted loci on chromosome 10 that affect in utero growth and development. However, other potential effects such as mental retardation will require long-term follow-up of this as well as additional cases. 相似文献
795.
The relationship between adaptation and mitigation in managing climate change risks: a regional response from North Central Victoria,Australia 总被引:1,自引:0,他引:1
Roger N. Jones Paul Dettmann Geoff Park Maureen Rogers Terry White 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):685-712
This two-part paper considers the complementarity between adaptation and mitigation in managing the risks associated with
the enhanced greenhouse effect. Part one reviews the application of risk management methods to climate change assessments.
Formal investigations of the enhanced greenhouse effect have produced three generations of risk assessment. The first led
to the United Nations Intergovernmental Panel on Climate Change (IPCC), First Assessment Report and subsequent drafting of
the United Nations Framework Convention on Climate Change. The second investigated the impacts of unmitigated climate change
in the Second and Third IPCC Assessment Reports. The third generation, currently underway, is investigating how risk management
options can be prioritised and implemented. Mitigation and adaptation have two main areas of complementarity. Firstly, they
each manage different components of future climate-related risk. Mitigation reduces the number and magnitude of potential
climate hazards, reducing the most severe changes first. Adaptation increases the ability to cope with climate hazards by
reducing system sensitivity or by reducing the consequent level of harm. Secondly, they manage risks at different extremes
of the potential range of future climate change. Adaptation works best with changes of lesser magnitude at the lower end of
the potential range. Where there is sufficient adaptive capacity, adaptation improves the ability of a system to cope with
increasingly larger changes over time. By moving from uncontrolled emissions towards stabilisation of greenhouse gases in
the atmosphere, mitigation limits the upper part of the range. Different activities have various blends of adaptive and mitigative
capacity. In some cases, high sensitivity and low adaptive capacity may lead to large residual climate risks; in other cases,
a large adaptive capacity may mean that residual risks are small or non-existent. Mitigative and adaptive capacity do not
share the same scale: adaptive capacity is expressed locally, whereas mitigative capacity is different for each activity and
location but needs to be aggregated at the global scale to properly assess its potential benefits in reducing climate hazards.
This can be seen as a demand for mitigation, which can be exercised at the local scale through exercising mitigative capacity.
Part two of the paper deals with the situation where regional bodies aim to maximise the benefits of managing climate risks
by integrating adaptation and mitigation measures at their various scales of operation. In north central Victoria, Australia,
adaptation and mitigation are being jointly managed by a greenhouse consortium and a catchment management authority. Several
related studies investigating large-scale revegetation are used to show how climate change impacts and sequestration measures
affect soil, salt and carbon fluxes in the landscape. These studies show that trade-offs between these interactions will have
to be carefully managed to maximise their relative benefits. The paper concludes that when managing climate change risks,
there are many instances where adaptation and mitigation can be integrated at the operational level. However, significant
gaps between our understanding of the benefits of adaptation and mitigation between local and global scales remain. Some of
these may be addressed by matching demands for mitigation (for activities and locations where adaptive capacity will be exceeded)
with the ability to supply that demand through localised mitigative capacity by means of globally integrated mechanisms. 相似文献
796.
Paul E. Bibbins JR. Robert L. Anderson Dr. Jack M. Rary Howard W. Jones JR. 《黑龙江环境通报》1982,2(2):123-125
A 48,XXYY fetus was diagnosed prenatally in a 34-year old female who was seen at 18-5 weeks of pregnancy for genetic counselling and amniocentesis for advanced maternal age. The pregnancy was terminated, and skin and peripheral blood samples were obtained at the time of delivery. These samples also exhibited the 48,XXYY chromosomal complement. 相似文献
797.
M. B. Jones 《Marine Biology》1975,30(1):13-20
The effects of cadmium (3CdSO4·8H2O), zinc (ZnSO4·7H2O) and lead [Pb (NO3)2] on mortality, and cadmium, zinc and mercury (HgCl2) on osmoregulation, have been recorded for marine and estuarine species of isopods (Crustacea). The marine species studied were Idotea baltica, I. neglecta, I. emarginata and Eurydice pulchra, which were adapted to 100, 80, 60 and 40% sea water (SW) (100% SW э 34‰ S). The estuarine species used were Jaera albifrons sensu stricto and J. nordmanni, which were adapted to 100, 50, 10 and 1% SW. Both groups of isopods have low mortalities in 100% SW with 10 and 20 ppm of cadmium, zinc and lead, but a decrease in salinity caused an increase in the toxicities of these metals and reduced the LT50 values (time, in hours, to 50% mortality). Mortalities at 10°C were generally higher than those recorded at 5°C. Cadmium had no significant effect on the osmoregulation of I. baltica and I. emarginata in 100 and 80% SW at 5°C, but this metal significantly lowered the blood osmotic concentration of I. neglecta in 80% SW. Zinc did not alter the haemolymph osmotic concentration of I. neglecta in 100 and 80% SW, but significantly lowered the blood osmotic concentration of I. baltica in 100% SW. Cadmium, zinc and mercury also significantly altered the osmoregulatory ability of J. albifrons in dilute saline. 相似文献
798.
J. W. Jones H. D. Bowen J. R. Bradley Jr R. E. Stinner R. S. Sowell 《Ecological modelling》1975,1(4):289-302
A model is presented for predicting boll weevil, Anthonomus grandis Boheman, feeding damage to cotton. The model uses appropriate probability theory based on behavioral components of male and nonreproducing female boll weevils and includes the effects of (1) differential feeding site preferences, (2) previous damage to the sites, and (3) individual insect behavior extended to feeding damage caused by a population of insects. The model is sensitive to both crop and insect parameters. An example of how this model can be used in an insect-crop ecosystem simulation is offered. 相似文献
799.
In the carnivorous isopod Eurydice pulchra
Leach the mid-gut caeca have a pH of 5.6 and produce a strong acid proteinase, a lipase and a carbohydrase. Electron microscope studies of the digestive caeca of starved and fed animals show that secretion is merocrine and may originate from a complex involving the basal cell membrane and associated mitochondria, producing lysosomes. Absorbed materials, in fed animals, appear to take the form of neutral lipid bodies, glycogen, and proteinaceous crystals, the latter forming within the golgi complex. Digestion of both lipid and protein inclusions was observed to occur intra-cellularly by fusion with free lysosomes. Secretion and absorption may occur in the same cell, and the scheme for the sequence of epithelial cell stages is proposed. 相似文献
800.