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Summary In the queenless antDiacamma australe, all workers eclose with a pair of tiny thoracic appendages (gemmae). These are sac-like and exhibit a distinct cuticular sculpturing, with minute pores opening on the outer surface. These pores are connected to glandular cells which completely fill the appendages, and thus an exocrine stignal is likely to be released. We discuss the social context of this signal: only one worker in each colony retains the gemmae. 相似文献
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L. Massart G. Peeters J. de Ley R. Vercauteren 《Cellular and molecular life sciences : CMLS》1947,3(4):154-155
Résumé MgCl2 et d'autres sels à des concentrations définies protègent la respiration de la levure de boulangerie contre l'action inhibitrice de colorants basiques. 相似文献
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Mercury-selenium correlations in marine mammals 总被引:8,自引:0,他引:8
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Palaeotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air 总被引:1,自引:0,他引:1
Noble-gas concentrations in ground water have been used as a proxy for past air temperatures, but the accuracy of this approach has been limited by the existence of a temperature-independent component of the noble gases in ground water, termed 'excess air' whose origin and composition is poorly understood. In particular, the evidence from noble gases in a Brazilian aquifer for a cooling of more than 5 C in tropical America during the Last Glacial Maximum has been called into question. Here we propose a model for dissolved gases in ground water, which describes the formation of excess air by equilibration of ground water with entrapped air in quasi-saturated soils. Our model predicts previously unexplained noble-gas data sets, including the concentration of atmospheric helium, and yields consistent results for the non-atmospheric helium isotopes that are used for dating ground water. Using this model of excess air, we re-evaluate the use of noble gases from ground water for reconstructing past temperatures. Our results corroborate the inferred cooling in Brazil during the Last Glacial Maximum, and indicate that even larger cooling took place at mid-latitudes. 相似文献
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E G Peeters 《Experientia》1987,43(1):74-81
The author reviews the background of the soil-cancer relationship. The study then goes into geocarcinogenic diseases in relation to soil composition, looking first at general factors: soil concentrations of selenium, caesium-rubidium-potassium, trace elements; natural radioactivity risks; cancer risks in connection with recycled waste water. In its final part, the study examines geocarcinogenic diseases linked with soil composition covering gastric cancer, cancer of the esophagus, urinary, breast, and bronchial cancer, pleural mesotheliomae and bone cancer. 相似文献
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M. Maes W. Stevens S. Scharpe E. Bosmans F. De Meyer P. D'Hondt D. Peeters P. Thompson P. Cosyns L. De Clerck C. Bridts H. Neels A. Wauters W. Cooreman 《Cellular and molecular life sciences : CMLS》1994,50(9):821-829
This study has been carried out in order to investigate seasonal variation in peripheral blood immune cells, such as leukocytes, monocytes, neutrophils, lymphocytes, CD3+ T, CD4+ T, CD8+ t, CD25+ T, CD20+ B, and serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R) and sIL-2R levels in normal volunteers. Toward this end, 26 normal volunteers (13 men, 13 women) had monthly blood samplings during one calendar year for peripheral blood count, flow cytometric enumeration of peripheral leukocyte subsets and immunoassays of IL-6, sIL-6R and sIL-2R. It was found that most of the immune variables change rhythmically during the seasons as a group phenomenon. Statistically significant yearly variations with seasonal rhythms, i.e. annual rhythms or harmonics, such as semiannual, tetramensual and trimensual rhythms, were found in the number of leukocytes, neutrophils, monocytes, lymphocytes, CD4+ T, CD8+ T, CD25+ T, CD20+ B cells, in the CD4+/CD8+ ratio, and serum IL-6 and sIL-6R levels. It is concluded that the immune system is characterized by a multifrequency time-structure with significant high-amplitude yearly variations in the number of some peripheral blood leukocyte subsets. 相似文献
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