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In order to investigate the pigeon's compass mechanism, a series of overcast tests with clock-shifted birds were run at two familiar release sites. While controls were able to assume a correct homeward direction, the experimental birds' initial orientation cannot be explained either on the basis of a time-compensated sun compass or of a time-independent magnetic compass. Speculative explanations of our paradoxical results are attempted.  相似文献   

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Precipitating tests carried out on cellulose acetate membrane were revealed by treating the immune complexes with enzyme linked anti-immunoglobulin antibodies. We insist on the importance of ELIEDA (enzyme-linked-immuno-electro-diffusion-assay) and ELIDEPA (enzyme-linked-immuno-double-electro-phoresis-assay) for the study of antibody classes involved in the immune response.  相似文献   

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Summary Information on the sources of cadmium in food are presented and the effects of raised environmental levels of cadmium on the concentration of cadmium in plant based foods, fish and shellfish, meat and offals, and dairy produce are discussed. Information is also presented on normal dietary intakes of cadmium and how these intakes may be elevated by environmental pollution or atypical dietary habits. The estimation of dietary intakes of cadmium using data about extreme intakes of specific foods is described.The author wishes to thank the Ministry of Agriculture, Fisheries and Food for permission to publish this paper.  相似文献   

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Summary I.p. (±)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.  相似文献   

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Summary Molybdate and copper(II)-histidine form an insoluble complex of empirical formula Cu2(His)3(MoO4)2(H2O)2. ESR-spectroscopy indicated that the complex had tetragonal symmetry. IR-spectroscopy showed the presence of a carboxylate anion and suggested that the molybdate ion formed an ammonium-type salt with the nitrogens of the imidazole. The complex did not form following dissociation of the protonated imidazole (above a pH of approximately 6).Acknowledgments. Drs C. Tennant, D. McGavin and B. Cleverly, Chemistry Division, D.S.I.R., Petone, for the computer simulated ESR spectrum and for help in interpreting ESR- and IR-spectra; Prof. A. D. Campbell, Department of Chemistry, University of Otago, Dunedin, for C,H,N- and H2O-microanalyses.  相似文献   

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This paper is concerned with the determination of simultaneous confidence regions for some types of time series models. We derive recursive formulas which allow the determination of the probability for an AR(1) stationary process based on exponential inputs to lie under any sequence of constants during N steps. Also, probabilities of the same form are derived for an MA(1) process, based on an exponentially distributed white noise. Numerical results are obtained and comparison of prediction regions for different values of ϕ or θ is made. The results show how the use of the correlation structure of the models can reduce the confidence regions area. © 1997 by John Wiley & Sons, Ltd.  相似文献   

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Résumé Des graines deNigella damascena et des graines d'orge ont été irradiés par les rayons du Co60 ainsi que par des neutrons rapides. Ils ont ensuite été traités par la déoxyfluorouridine (FUDR) après différents temps de prégermination. On a observé que FUDR accroissait de manière nette les effets totaux des rayons sur les chromosomes (taux d'aberrations en anaphase). Par contre les effets des neutrons rapides n'ont été que faiblement modifés. Des effets synergiques ont également été obtenus chez l'orge après des traitements consécutifs FUDREMS.  相似文献   

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用原位聚合法制备了Sr0.7La0.15Ce0.15Fe11.7Zn0.3O19铁氧体/聚苯胺(PAn)复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)对样品的结构、微观表面形貌和粒子大小进行了表征,用微波矢量网络分析仪测量样品在2~12.4GHZ频率范围内复介电常数和复磁导率,根据测量数据计算微波反射率R与频率f的关系。研究结果表明:PAn包覆于掺杂锶铁氧体表面,PAn/Sr0.7La0.15Ce0.15Fe11.7Zn0.3O19复合材料具有良好的吸波性能,随着掺杂锶铁氧体含量的增加,微波吸收匹配厚度和吸收带宽发生变化:当Sr0.7La0.15Ce0.15Fe11.7Zn0.3O19聚合质量比为40%时,最佳匹配厚度为2.6mm,吸收峰值接近-40dB,峰值频率高于12.4GHz,大于10dB吸收带宽预计达到55GHz。  相似文献   

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M A Pitt 《Experientia》1977,33(11):1410-1412
Molybdate and copper(II)-histidine form an insoluble complex of empirical formula Cu2(His)3(MoO4)2(H2O)2ESR-spectroscopy indicated that the complex had tetragonal symmetry. IR-spectroscopy showed the presence of a carboxylate anion and suggested that the molybdate ion formed an ammonium-type salt with the nitrogens of the imidazole. The complex did not form following dissociation of the protonated imidazole (above a pH of approximately 6).  相似文献   

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Riassunto Se si mantengono Planarie (Dugesia lugubris) per otto giorni in una soluzione di LSD (0,02 mg/ml), si nota un aumento di RNA nella parte cefalica del soggetto rispetto ai corpi e anche rispetto alle teste dei controlli. Anche l'incorporazione di uridina triziata segue lo stesso andamento. Vengono proposte alcune ipotesi.  相似文献   

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Riassunto Si è studiata la natura delle cellule immunologicamente competenti della milza diX. laevis Daud. Mediante la tecnica della immuno-cito-aderenza, si è potuto constatare che tali cellule estratte da milze di animali immunizzati con globuli rossi di pollo e coniglio, rispondono ad uno solo o ad ambedue gli antigeni, che la percentuale delle cellule che reagiscono sia contro le emazie di coniglio che di pollo è di molto superiore a quella dei mammiferi e che tale percentuale non varia al variare delle dosi di antigene somministrato.  相似文献   

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