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STEPHEN T. EMLEN 《Ibis》1996,138(1):87-100
Family-dwelling birds provide excellent opportunities for testing evolutionary predictions about social interactions among relatives. Their combination of behavioural complexity with cultural simplicity makes them ideal model systems in which to search for fundamental biological rules of social interaction. In this plenary, I provide a personalized overview of current thinking about both the evolution of families and the social dynamics to be expected among family members. Using an adaptationist/economic approach that uses fitness as its currency, I develop a set of 15 predictions about family formation, family stability, familial cooperation, familial competition and conflict resolution among kin. I argue that knowledge of four basic parameters, genetic relatedness, social dominance, the benefits of group living and the probable success of independent reproduction, can explain many aspects of family life in birds. I further suggest that this evolutionary perspective is generalizable across taxa and will provide new insights into understanding animal family systems in other species, including our own.  相似文献   

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Nitronyl nitroxides, such as derivatives of 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl 3-oxide (PTIOs), react with *NO to form the corresponding imino nitroxides (PTIs) and *NO2. PTIOs are considered as monitors of *NO, stoichiometric sources of *NO2, biochemical and physiological effectors, specific tools for the elimination of *NO, and potential therapeutic agents. However, a better understanding of the chemical properties of PTIOs, especially following their reaction with *NO, is necessary to resolve many of the reported discrepancies surrounding the effects of PTIOs and to better characterize their potential therapeutic activity. We have generated electrochemically the oxidized and reduced forms of PTIO and carboxy-PTIO (C-PTIO), characterized their absorption spectra, and determined the reduction potentials for the oxoammonium/nitroxide and nitroxide/hydroxylamine couples. The rate constants for the reaction of *NO2 with PTIO and C-PTIO to form the corresponding oxoammonium cations (PTIO+s) and nitrite were determined to be (1.5 - 2) x 10(7) m-1 s-1. We have also shown that the reactions of PTIO+s with *NO form PTIOs and NO2-. The rate constants for these reactions are approximately 30-fold higher than those for the reactions of PTIOs with *NO or O2-*. The present results show that (i) the reaction of PTIOs with *NO forms solely PTIs and NO2- where [NO2-]/[PTI] varies between 1 and 2 depending on the steady-state concentrations of *NO. Consequently, quantitation of *NO is valid only at sufficiently low fluxes of *NO; (ii) the reaction of PTIOs with *NO can be used as a valid source of *NO2 only when the latter is effectively scavenged by an appropriate reductant; and (iii) the formation of peroxynitrite cannot be efficiently inhibited by PTIOs even under relatively low fluxes of *NO and O2-* and millimolar levels of PTIOs.  相似文献   

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Summary The segregation of factor B(BF)F subtypes was analyzed in conjunction with other MHC markers in 15 families with 89 offspring. Informative data for BF F subtypes were obtained from 11 families, 6 of them with known recombinant individuals for the HLA-B/DR/GLO region. The subtypes did not contribute further to the localization of the cross-overs, but followed the known segregation of conventional BF allotypes. In 2 families of one kinship, the recognition of heterozygous BF*FAFB individuals could be established following the inclusion of three generations. The rarer of the two BF F subtype alleles, BF*FA, is positively associated with the HLA haplotypes BW62, CW3, C4A*3 and A29, CWX, B44, C4A*3, B*1, DR7. BF F subtypes are regarded as a very useful additional tool for studies of MHC organization and disease association.  相似文献   

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Continuing problems with gray literature*   总被引:1,自引:1,他引:0  
Frequent gatherings, such as those on coastal management, have resulted in increased production of gray literature like conference proceedings and institutional reports, which are published without adequate peer review. In developing countries like those in southeast Asia, manuals and other publications used in workshops and training programs seldom use peer-reviewed references. Among papers sampled, those in conference proceedings have lower percentages of citations to peer-reviewed journals, whether or not the proceedings are issued as books or journal supplements. From three proceedings and one institutional report with a total of 37 papers and an average of 22 cited references per paper, citations to gray literature averaged 92 percent of total citations. This poor quality of the reference lists decrease the credibility of a paper. Scientific conferences should be designed to reverse the production and use of gray literature by limiting the scope of the proceedings to invited reviews, with other presentations appearing only as abstracts to encourage their ultimate publication in peer-reviewed journals. A conference book of reviews by respected scientists will then support incorporation of scientific information into policy and management decisions for more effective coastal management.  相似文献   

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The nucleotide sequence data reported in this paper have been submitted to the EMBL/GenBank nucleotide sequence database and have been assigned the accession number Z48631. The name listed for this sequence was officially assigned by the WHO Nomenclature Committee in November 1994. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report (Bodmer et al. 1994), names will be assigned to new sequences as they are identified. Lists of such new names will be published in the following WHO Nomenclature Report  相似文献   

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