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Summary The dance communication of honeybees was studied using the short-winged mutant diminutive wings. The wing area of the mutant is reduced to 67% that of the wild type. This reduction in wing area leads to increases in both the wing beat frequency and the frequency of the sounds emitted during the dances. At the same time the amplitude of the sound signals is reduced. These changes have a strong effect on the recruitment success of the dances, which is reduced to less than 50%. Thus, the acoustical signals emitted by dancing bees play an essential role in the bees' dance communication. 相似文献
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We investigated unhatched eggs (n = 57) of Goshawks (Accipiter gentilis) from the period 1988--2002 and compared them with eggs (n = 134) from 1971--1978. Mean concentrations of PCBs, sigmaDDT and HCB in the earlier period were (mg kg(-1) lipid weight) 50.1, 126.6, and 117.7, while the values from the later period were statistically significantly lower: 27.7, 4.1, 0.1, respectively. Nevertheless, the concentration of PCB is relatively constant during the last 8-10 years. The variability of residues was lower within clutches than among clutches. No age-dependent accumulation in eggs could be demonstrated. A statistically significant lower shell index was measurable for the period 1971--1978, while this index during 2001--2002 was relatively high as it was during the late 18th century. We are suggesting a threshold value for effect concentrations on shell index. Residues of the DDT-group had an influence on the number of fledged young per nest site. 相似文献
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The localization of antigens and other substances in cells and tissues by electron microscopy is usually performed by immunohistochemical techniques employing labelled conventional or monoclonal antibodies. For the ultrastructural localization of the antibodies, they are coupled to electron-dense labels like gold or ferritin. Here, we demonstrate a novel method to localize antigens in cells, tissues, and on other supports. By electron energy loss spectroscopy (EELS) it is possible to directly analyze the distribution of antigens, metabolites or other substances without the use of labelled antibodies: as an example we demonstrate the distribution of the immunomodulator lipopeptide in B lymphocytes and macrophages. EELS represents a novel, sensitive, and generally applicable method for the detection and localization of antigens and other substances in biology and medicine. 相似文献
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The Science of Nature - 相似文献
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