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71.
Henrietta Nittby Arne Brun Susanne Str?mblad Mehri Kaviani Moghadam Wenjun Sun Lars Malmgren Jacob Eberhardt Bertil R. Persson Leif G. Salford 《The Environmentalist》2011,31(2):140-148
Since the late 1980s, our group has examined the effects of radiofrequency electromagnetic fields (RF-EMF), including pulse-modulated waves of the type emitted by mobile phones, upon the blood?Cbrain barrier. In more than 2,000 rats, we have repeatedly demonstrated a passage of the rats?? own albumin from the blood through the brain capillaries into the surrounding brain parenchyma at SAR values down to 0.1mW/kg. In most of these experiments, the animals were exposed in TEM-cells, ventilated by an external electrical fan at 50 Hz. In the present study, we examined whether the extremely low frequency (ELF) magnetic fields from the fan (50 Hz, 0.3?C1.5 ??T) might add to the RF effect. Sixty-four rats were divided into 4 groups: RF only, ELF only and RF + ELF exposure plus a sham group. The GSM-900 MHz RF exposure was at the very low, nonthermal, average whole-body SAR level 0.4 mW/kg. Demonstration of the normally occurring albumin extravasation in the basal hypothalamus is our inbuilt control proving that the staining is reliable. Two full series of staining of the whole material gave negative results for hypothalamus. Not until we changed to avidin, biotin, and antibodies from a third supplier, we received an acceptable staining. Twenty-five percent of the RF animals had a pathological albumin leakage, while the ELF and RF + ELF groups with three and two pathological findings, respectively, were not significantly different from the control group. We conclude that the use of external fans has had no major influence upon the result. 相似文献
72.
Coastal swamps are among the rapidly vanishing wetland habitats in Louisiana. Increased flooding, nutrient and sediment deprivation, and salt-water intrusion have been implicated as probable causes of the decline of coastal swamps. We developed a two-species individual-based forest succession model to compare the growth and composition of a cypress-tupelo swamp under various combinations of flooding intensity and salinity levels, using historical time-series of stage and salinity data as inputs. Our model simulates forest succession over 500 years by representing the growth, mortality, and reproduction of individual Taxodium distichum (baldcypress) and Nyssa aquatica (water tupelo) trees in a 1-km2 spatial grid of 10 m × 10 m cells that vary in water levels and salinity through differences in elevation. We independently adjusted the elevations of each cell to obtain different grid-wide mean elevations and standard deviations of elevation; this affected the temporal and spatial pattern of flooding. We calibrated the model by adjusting selected parameters until averaged basal area, stem density and wood production rates under two different mean elevations (partially versus highly flooded) were qualitatively similar to comparable values reported for swamps in the literature. Corroboration involved comparing model predictions to four well-monitored contrasting habitat sites within the Maurepas Basin, Louisiana, USA. Model predictions of both species combined showed the same patterns among sites as the data, but the model overestimated wood production and the dominance of T. distichum. Exploratory simulations predicted that increased flooding leads to swamps with reduced basal areas and stem densities, while increased salinity resulted in lower basal areas at low salinity concentration (∼1-3 psu) and complete tree mortality at higher salinity concentrations (∼2-6 psu). Our model can provide insight into the succession dynamics of coastal swamps and information for the effective design of restoration actions. 相似文献
73.
74.
Jannika?E.?Bostr?mEmail author Cecilia?Kullberg Susanne??kesson 《Behavioral ecology and sociobiology》2012,66(5):819-821
In a previous study, we found that juvenile northern wheatears (Oenanthe oenanthe) exposed to a magnetic displacement to the west of their natural migration route increased their body mass. The total intensity
and inclination used for the western displacement may also have been interpreted as northern compared to the experimental
site (stronger total field intensity and steeper inclination angle). In order to investigate whether the fuelling response
was a response to an unexpected magnetic field or specific to the northern magnetic field, we conducted a new experiment.
Juvenile wheatears from the same study population were magnetically displaced to southwestern magnetic fields, exposing the
birds to unexpected magnetic combinations, but eliminating the possible effect of a northern magnetic field. A control group
was kept in the local geomagnetic field in Sweden for comparison. There was no difference in body mass increase between treatments,
suggesting that the fuelling response previously found was not a simple response to an unexpected magnetic field, but rather
a specific response to the northern magnetic field. Juvenile wheatears may have developed a fuelling response to northern
magnetic fields in order to enable a successful flight towards the migration goal. 相似文献
75.
Manfred Niecke Andreas Krüger Peter Hauff Hermann Ellenberg Ralph Labes Susanne Niecke 《Environmental Sciences Europe》1998,10(1):3-14
With the aid of the Hamburg proton micro-probe, we examined the concentration of mercury in sea eagle feathers collected over the course of several decades in the Mecklenburg-Vorpommern area. Based on the sites where these feathers were collected and the data of these findings, it is possible to get a differential picture of mercury contamination related both temporally and regionally to the mercurial pollution of seed mordants used agriculturally. We compared the concentrations found with a basic “geogenic” contamination which was also to be seen in the feather samples from the last century as detected in museum animal specimens. 相似文献
76.
Susanne Stern Ulf Sonesson StefanGunnarsson Ingrid Öborn Karl-Ivar Kumm Thomas Nybrant 《Ambio-人类环境杂志》2005,34(4):396-401
为了研究未来的可持续生产系统,本文采用循序渐进的方法,基于不同可持续发展目标,设计了3种生猪生产情景.第一种情景集中考虑动物福利和动物的自然行为.第二种情景则以对环境影响最小,有效利用自然资源为目标.第三种情景以产品质量和安全为目标.每一种情景各自实现可持续发展不同方面的目标,但是这些目标存在着冲突,没有哪种情景能够实现所有的目标.之后,将情景参数化,使用生命周期评估(LCA)方法,计算各自对环境的影响,并用同一套数据计算经济成本.计算结果是,每公斤猪肉成本以动物福利情景最高,其它两种情景成本较为接近.环境情景的环境影响最低,产品质量情景的环境影响最大.最后,基于未来的不同优先序,讨论各个结果. 相似文献
77.
本文通过在东非进行的一系列野外和实验室试验,研究了丰富的红树林十足类螃蟹迈纳新胀蟹(Neosarmatium meinerti)对落叶的清理.在地势高的海榄雌(Avicennia meinerti)潮间带,螃蟹掩埋了所有红树林林区海底的落叶,而且会在2小时内平均消耗其中的67%. 相似文献
78.
79.
Bernd Eiben Susanne Hansen Jutta Knipping Regina Massenberg Richard Goebel Wilhelm Hammans 《黑龙江环境通报》1989,9(5):365-367
Chorionic villus samples from a healthy pregnant female were obtained for first-trimester prenatal diagnosis. A translocation trisomy 21 was diagnosed. A consecutive amniocentesis revealed a normal male karyotype. At term a healthy boy was born. Cytogenetic analysis from cord blood showed a regular karyotype of 46,XY, whereas in term placenta a pathological karyotype of 47,XY,+mar was found. 相似文献
80.