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1.
In agglomerative hierarchical clustering, pair-group methods suffer from a problem of non-uniqueness when two or more distances
between different clusters coincide during the amalgamation process. The traditional approach for solving this drawback has
been to take any arbitrary criterion in order to break ties between distances, which results in different hierarchical classifications
depending on the criterion followed. In this article we propose a variable-group algorithm that consists in grouping more
than two clusters at the same time when ties occur. We give a tree representation for the results of the algorithm, which
we call a multidendrogram, as well as a generalization of the Lance andWilliams’ formula which enables the implementation of the algorithm in a recursive
way.
The authors thank A. Arenas for discussion and helpful comments. This work was partially supported by DGES of the Spanish
Government Project No. FIS2006–13321–C02–02 and by a grant of Universitat Rovira i Virgili. 相似文献
2.
Summary The disappearance of thrombin—formed in the blood, or added to serum-follows a manomolecular reaction-type. Heparin increases the reaction-velocity of this thrombin-inactivating process.Our investigation established that toluidine blue or kinase, which, according to the literature, bind heparin, strongly reduce the speed of thrombin-inactivation too. Therefore the heparin-binding capacity of these substances is also manifested in the decrease of thrombin-inactivation. 相似文献
3.
岳崇兴 《河南师范大学学报(自然科学版)》1995,(1)
本文用TC(Technicolor)模型,解释了L3L ̄+L ̄-γγ事例,具体分析发现四个L3事例可以由过程z→ρ°ρ°→L ̄+L ̄-P°(γγ)产生。 相似文献
4.
Ramsés Fuenmayor 《Systemic Practice and Action Research》1991,4(5):473-490
Both an ontoepistemology for reductionist modern science (counter-ontoepistemology) and an ontology for interpretive Systemology have been outlined in the two preceding papers in this special issue ofSystems Practice. In the present article, the notion of “truth” is interpreted in terms of both the ontoepistemology of “reductionism” and the ontology of interpretive systemology. Both interpretations are discussed. Such a discussion represents the objective of this paper, that is, to outline the epistemological “face” of the ontoepistemology of interpretive systemology. In order to design that “epistemological face,” the relation between ontology and epistemology must be clarified. Such a relation is seen from the standpoint already provided by the ontology. After the discussion on the notion of truth, the general shape of a systemic-interpretive inquiring process is outlined. 相似文献
5.
D. Migliore-Samour M. Delaforge M. Jaouen D. Mansuy P. Jollès 《Cellular and molecular life sciences : CMLS》1989,45(9):882-886
Summary Immunomodulating lipopeptides lauroyl-L-Ala--D-Glu-LL-A2pmNH2-Gly (RP 44.102) and lauroyl-L-Ala--D-Glu-LL-A2pmNH2 (RP 56.142) were found to protect mice against the hepatotoxicity of paracetamol, which is due to cytochrome P-450 dependent formation of toxic metabolites and radicals. In fact they decreased the amount of hepatic microsomal cytochrome P-450, and the level of CCl4-induced lipid peroxidation. In contrast lauroyl-L-Ala--D-Glu-DD-A2pmNH2 (RP 53.204), which only differs by the configuration of the two chiral carbons of A2pm (diaminopimelic acid) and is not an immunomodulating agent, failed to protect against poisoning by paracetamol and had no effect on the level of hepatic cytochrome P-450 or the microsomal CCl4-induced lipid peroxidation. This provides a clear connection between the immunostimulating properties of a compound and its effects on xenobiotic biotransformations. 相似文献
6.
Hormogón M 《Annals of science》1991,48(2):187-190
7.
8.
Summary Cyclic voltammetry of molecular oxygen in aprotic media (dimethylformamide) and in the presence of bilirubin and other bile pigments shows that superoxide anion (
) undergoes proton-induced dismutation. Lactam hydrogens of bile pigments are sufficiently acid to induce
disproportionation to O2 and H2O2. Because of its characteristic lipophilic behavior, a biological role for natural bilirubin similar to that of other non-enzymatic lipophilic scavengers of
is suggested. 相似文献
9.
10.
B. Stankiewicz-Choroszucha J. Górski 《Cellular and molecular life sciences : CMLS》1978,34(3):357-358
Summary It was shown in the rat that mobilization of intramuscular triglyceride during exercise is controlled by the adrenergic system.Acknowledgments. The work was supported by the Polish Academy of Sciences, grant No. 10.4.2.01.3.2. 相似文献