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151.
For the first time, concentrations of the long lived radon progenies 210Pb, 210Bi and 210Po were measured in the mine atmosphere of the so called "healing gallery" in Badgastein, Austria, a region famous for its radioactive springs. These investigations were performed in order to study the radioactive equilibrium between the 210Pb-210Bi and the 210Pb-210Po pairs so as to gain more information about the aerosol-forming processes in the mine. The particle size distribution of the aerosols was determined under different ventilation conditions. Six-stage and eight-stage cascade impactors with working ranges from 0.15 to5 µm and from 0.063 to 8 µm, respectively, were used to collect the mine aerosols. These samples were analysed in the laboratory and measured by liquid scintillation spectrometry. The most surprising results were found under full ventilation, when the total activity concentrations of 210Pb, 210Bi and 210Po were 4.6, 2.0 and 16.5 mBq/m3, respectively. In this case 210Po/210Pb activity ratios ranged between 1.8ǂ.3 and 4.3ǂ.3. These unexpected results were confirmed by the eight-stage impactor samples. For the smallest particles, between 0.062 and 0.125 µm, an even higher value of 7.5 was observed. As outside sources could be excluded, such 210Po enrichments must occur during the aerosol-forming process itself inside the mine. 相似文献
152.
153.
Alessandra Capponi Dr Giuseppe Rizzo Donatella Rinaldo Domenico Arduini Carlo Romanini 《黑龙江环境通报》1995,15(11):1007-1016
The objective of this study was to evaluate the effect of fetal blood sampling on cardiac flow velocity waveforms. Flow velocity waveforms were measured from the ascending aorta and pulmonary artery immediately before and after fetal blood sampling in 29 normally grown and 12 growth-retarded fetuses. The latter group was characterized by abnormal Doppler indices in the umbilical artery and middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The flow velocity parameters studied were the peak velocity, the time to peak velocity, and the left and right cardiac output and their ratio. In normally grown fetuses, the peak velocity and right and left cardiac output values increased significantly after fetal blood sampling, while no significant changes were observed in the other indices considered. The gestational age at the time of the procedure was positively related to the amplitude of these changes. In growth-retarded fetuses, fetal blood sampling did not induce any significant increase in cardiac output or peak velocities, while in more than 50 per cent of the fetuses these Doppler indices decreased. The amplitude of the decrease was significantly related to the severity of acidosis in the umbilical vein. In conclusion, the cardiac haemodynamic response to fetal blood sampling differs between normally grown and growth-retarded fetuses. This difference may explain the higher rate of complications occurring in the latter group of fetuses after blood sampling. 相似文献
154.
Bruno Brambati Lucia Tului Alessandro Lanzani Giuseppe Simoni Maurizio Travi 《黑龙江环境通报》1991,11(10):767-774
Both the principles of first-trimester genetic diagnosis in multiple pregnancy and the special considerations required to avoid potential diagnostic pitfalls are presented. The experience consisted of 65 cases of twins and one case of quadruplets. Dichorionic twins were recognized by sonography in 54 cases. Transabdominal aspiration was generally preferred to trans-cervical for obtaining chorionic tissue, although in two cases both approaches were used. Diagnostic error following erroneous sampling was reported in 3 out of 54 sets of dichorionic twins (5.5 per cent). When like-sex dichorionic twins cannot be differentiated by cytogenetic or DNA polymorphism studies, amniocentesis should be recommended to confirm the reliability of the result on chorionic tissue. 相似文献
155.
A ring chromosome 19 was found in 14 of 20 metaphases (67 per cent) derived from amniotic fluid cell cultures following amniocentesis because of increased maternal age. Elective termination of the pregnancy revealed a hypotrophic female fetus with mild dysmorphic signs, but no congenital malformations. The case is discussed in relation to three reports in the literature of ring chromosome 19 mosaicism in a phenotypically normal girl, a mentally retarded man, and a boy with normal psychomotor development and minor dysmorphic features. 相似文献
156.
Giaufausto Salvadori Sergio P. Ratti Giuseppe Belli 《Environmental science and pollution research international》1997,4(2):91-98
A few case studies will be presented involving both radioactive and chemical pollution at small, medium, and large space-time
scales. Reported are recent advances in the field of environmental pollution involving the use of fractals and multifractals.
The mathematical tools proposed here may offer new perspectives for investigating many of the problems of nonlinear variability
which commonly arise when dealing with pollutants, such as the presence of outliers and the sparseness of the sampling networks.
They may also lead to a simplification of the models adopted for studying natural phenomena, thanks to a scaling approach.
Finally, they may provide parameters whose values are directly related to the nonlinear dynamics involved in the pollutant
distribution in the environment which, in turn, may be relevant for computer simulation and epidemiological or risk assessment
purposes. 相似文献
157.
158.
Hildegard Fischer Hans -Jürgen Kretzschmar Gabriele Christoph Volker Neyen 《Environmental Sciences Europe》1994,6(4):189-195
The infra-red (IR) and the gas Chromatographic (GC) methods for the determination of mineral oil hydrocarbons in soils were examined in collaborative trials with regard to their accuracy and reproducibility. Natural, homogenized soils and soils spiked with mineral oil were used as standards. The soil matrix was composed relatively simply. The repeatability and reproducibility values obtained were about 5 % und 23 %, respectively. In contrast, the GC method revealed a considerably higher error range, especially by using the split/splitless technique. The degradation of mineral oil hydrocarbons in soils under different temperatures was investigated by IR throughout one year. The degradation rate at room temperature was about 25 %; at lower temperatures no degradation was detected. Thus, the spiked soils may be used as calibration standards for the mineral oil analysis. 相似文献
159.
Chelli–Cheheb Razika Arzarello Marta Arnaud Julie Berto Claudio Cáceres Isabel Caracausi Sandro Colopi Francesco Daffara Sara Canini Guido Montanari Huguet Rosa Karambatsou Theodora Sala Benedetto Zambaldi Maurizio Berruti Gabriele L. F. 《Die Naturwissenschaften》2020,107(4):1-13
The Science of Nature - Female-only colour polymorphism is rare in birds, but occurs in brood parasitic cuckoos (Cuculidae). Obligate brood parasites leave incubation and parental care to other... 相似文献
160.
Giuseppe Donati An Bollen Silvana M. Borgognini-Tarli Joerg U. Ganzhorn 《Behavioral ecology and sociobiology》2007,61(8):1237-1251
Animals show specific morphological, physiological and behavioural adaptations to diurnal or nocturnal activity. Cathemeral
species, i.e. animals with activities distributed over the 24-h period, have to compromise between these specific adaptations.
The driving evolutionary forces and the proximate costs and benefits of cathemerality are still poorly understood. Our goal
was to evaluate the role of predator avoidance, food availability and diet quality in shaping cathemeral activity of arboreal
mammals using a lemur species as an example. For this, two groups of collared lemurs, Eulemur collaris, were studied for 14 months in the littoral forest of southeastern Madagascar. Data on feeding behaviour were collected during
all-day and all-night follows by direct observation. A phenological transect containing 78 plant species was established and
monitored every 2 weeks to evaluate food availability during the study period. Characteristics of food items and animal nutritional
intake were determined via biochemical analyses. The ratio of diurnal to nocturnal feeding was used as response variable in
the analyses. The effects of abiotic environmental variables were removed statistically before the analyses of the biotic
variables. We found that diurnal feeding lasted longer during the hot–wet season (December–February), whereas nocturnal feeding
peaked during the hot–dry and cool–wet seasons (March–August). Although the lemurs foraged mostly in lower forest strata during
daylight and used emergent trees preferably at night, the variables which measured animal exposure to birds of prey failed
to predict the variation of the ratio of diurnal/nocturnal feeding. Ripe fruit availability and fiber intake are the two variables
which best predicted the annual variation of the lemur diurnality. The data indicate that feeding over the whole 24-h cycle
is advantageous during lean periods when animals have a fibre-rich, low-quality diet. 相似文献