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1.
T. J. Wojciechowski 《Biometrical journal. Biometrische Zeitschrift》1987,29(8):953-959
In this paper very simple nonparametric classification rule for mixtures of discrete and continuous random variables is described. It is based on the method of nearest neighbor proposed by Cover and Hart (1967). The bounds on the limit of the nearest neighbor rule risks are given. Both lower and upper bound depend on the Bayes risk and the loss function. Finally the method is compared with other existing methods on some practical data set. 相似文献
2.
MICHAEL J. BENTON 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1982,15(2):115-132
Dictyodora occurs in the Hauptquarzit (Late Ordovician; D. zimmermanni) and Bordenschiefer (Early Carboniferous; D. liebeana) of Thuringia, East Germany. It is absent in the Early Devonian Nereitenquarzit, and analysis of the trace fossil assemblages points to environmental partitioning within the ‘deep-sea’Nereites Association. The Carboniferous Dictyodora was much larger than the Early Palaeozoic forms and had a long respiratory (?) wall organ. This may have been an adaptation to feeding deeper in anoxic sediments, and the animal developed large ‘parapodia’ to effect its progression through the sediment. 相似文献
3.
Phylogenetic analyses of primate size evolution: the consequences of sexual selection 总被引:6,自引:0,他引:6
Patrik Lindenfors Birgitta S. Tullberg 《Biological journal of the Linnean Society. Linnean Society of London》1998,64(4):413-447
We have analysed the relationship between primate mating system, size and size dimorphism by utilizing several phylogenetically based methods. An independent contrast analysis of male and female size (log weight) showed that these are tightly correlated and that size dimorphism is not a simple allometric function of size. We found no relationship between mating system and sexual dimorphism in strepsirhines but a strong relationship in haplorhines. By matched-pairs analysis, where sister groups were matched according to whether the mating system predicted higher or lower intrasexual selection for male size, haplorhine species in more polygynous clades (with a predicted higher sexual selection) were significantly more dimorphic, had larger males, and also, but to a lesser degree, larger females. Both independent contrast and matched-pairs analyses are non-directional and correlational. By using a directional test we investigated how a transition in mating system affects size and dimorphism. Here, each observation is the sum of changes in dimorphism or size in a clade that is defined by a common origin of a mating system. Generally, dimorphism, as well as male and female size, increased after an expected increase in sexual selection, and decreased after an expected decrease in sexual selection. The pattern was, however, not significant for all of the alternative character reconstructions. In clades with an expected increase in sexual selection, male size increased more than female size. This pattern was significant for all character reconstructions. The directional investigation indicates that the magnitude of change in haplorhine dimorphism is larger after an increase in sexual selection than after a decrease, and, for some reconstructions, that the magnitude of size increase is larger than the magnitude of size decrease for both sexes. Possible reasons for these patterns are discussed, as well as their implications as being one possible mechanism behind Cope's rule, i.e. general size increase in many phylogenetic lineages. 相似文献
4.
SHOMITA MUKHERJEE COLIN GROVES 《Biological journal of the Linnean Society. Linnean Society of London》2007,92(1):163-172
There is a striking difference in body size of jungle cats ( Felis chaus ) in the west and the east of their distribution, with Israeli cats being 43% heavier than Indian cats. We tested the hypothesis that increasing competition from other small felids towards the east is responsible for the difference in body size. We measured jungle cat skulls for eight cranial and dental variables and related these to independent variables such as species richness (local and regional), latitude, longitude, temperature, and precipitation. Data from a narrow band between latitudes 24.0°N and 33.9°N, where Bergmann's rule was largely not observed, showed that the western population (≤ 50.0°E longitude) of jungle cats is larger than the eastern (> 60.0°E longitude) population with the size difference being most evident in the upper carnassials (P4 L). Species richness at the regional level showed a significant negative relation to P4 L. An even spacing in condylobasal length for a small-cat guild from India through null model analysis indicated the occurrence of character displacement. The results support the hypothesis that competition is responsible for geographical variation in jungle cat body size in the region where Bergmann's rule does not apply. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 163–172. 相似文献
5.
Estimation in linear models with censored data 总被引:1,自引:0,他引:1
6.
A note on optimality in lattice square designs 总被引:1,自引:0,他引:1
7.
Forest density expressing the stocking status constitutes the major stand physiognomic parameter of Indian forest. Density
and age are often taken as surrogate to structural and compositional changes that occur with the forest succession. Satellite
remote sensing spectral response is reported to provide information on structure and composition of forest stands. The various
vegetation indices are also correlated with forest canopy closure. The paper presents a three way crown density model utilizing
the vegetation indices viz., advanced vegetation index, bare soil index and canopy shadow index for classification of forest
crown density. The crop and water classes which could not be delineated by the model were finally masked from normalized difference
vegetation index and TM band 7 respectively. The rule based approach has been implemented for land use and forest density
classification. The broad land cover classification accuracy has been found to be 91.5%. In the higher forest density classes
the classification accuracy ranged between 93 and 95%, whereas in the lower density classes it was found to be between 82
and 85%. 相似文献
8.
Rao-Blackwellisation of sampling schemes 总被引:15,自引:0,他引:15
9.
Dr. Karl Kleemann 《Facies》1994,30(1):151-153
Summary The mytilid genusLithophaga is confirmed for the Upper Triassic. The Rhaetian specimen, boring the dead part of coral, is compared with the SenonianL. alpina, which is associated with live coral. 相似文献
10.
Valerie Gray Hardcastle 《Biology & philosophy》1993,8(2):173-192
I examine the branch of evolutionary epistemology which tries to account for the character of cognitive mechanisms in animals and humans by extending the biological theory of evolution to the neurophysiological substrates of cognition. Like Plotkin, I construe this branch as a struggling science, and attempt to characterize the sort of theory one might expect to find this truly interdisciplinary endeavor, an endeavor which encompasses not only evolutionary biology, cognitive psychology, and developmental neuroscience, but also and especially, the computational modeling of artificial life programming; I suggest that extending Schaffner's notion of interlevel theories to include both horizontal and vertical levels of abstraction best fits the theories currently being developed in cognitive science. Finally, I support this claim with examples drawn from computational modeling data using the genetic algorithm. 相似文献