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1.
Shape variations in the dentition and the cranium were analyzed for sevenSaguinus forms of the hairy-face tamarin by applying the factor analysis method. The results obtained for the dental and cranial measurements
were almost consistent with each other.
The magnitude of the difference in shape factors between theS. nigricollis group and theS. midas group is appreciably larger than that between the former group and theS. mystax group. If the ancestral geographic centre of origin is postulated as being within the region which is inhabited by the livingS. nigricollis group, the morphological distances between any pairs of groups correlate well with the geographic distances between them.
Concerning the dental and cranial morphologies, the physical changes in the three species group probably took place in two
directions; that is, from theS. nigricollis group to theS. mystax group, and from theS. nigricollis group to theS. midas group.
The forms belonging to each species group are more closely related to each other, with the exception ofS. imperator in theS. mystax group. The uniqueness ofS. imperator was clearly demonstrated by factor analysis and distance analysis. In theS. mystax group, although still hypothetical,S. imperator may have been related only through the basic ancestral stock toS. labiatus andS. mystax. 相似文献
2.
A. Joy Belsky 《Plant Ecology》1988,74(1):3-10
An index of vegetational heterogeneity in 16 grassland communities in the Serengeti National Park, Tanzania, was calculated using mean percent distance (MPD) among spatially separated quadrats. To determine whether regional factors such as annual precipitation, fire, soil sodicity, herbivore utilization, or percentage of species having clonal growth patterns influenced the amount of heterogeneity measured in individual grassland communities, the index was related to these factors by an interactively constructed multiple-regression model.Community heterogeneity varied in a curvilinear manner along a north-to-south transect; maximum values occurred in the center of the park with lower values near the northern and southern borders. Subsurface concentrations of Na+ and the presence or absence of mound-building termites were incorporated into the model, which explained 55% of the variability in grassland heterogeneity.Abbreviations PD=
Percentage Distance
- MPD=
Mean Percentage Distance 相似文献
3.
Summary We describe a simple method for determining the overall fold of a polypeptide chain from NOE-derived distance restraints. The method uses a reduced representation consisting of two particles per residue, and a force field containing pseudo-bond and pseudo-angle terms, an electrostatic term, but no van der Waals or hard shell repulsive terms. The method is fast and robust, requiring relatively few distance restraints to approximate the correct fold, and the correct mirror image is readily determined. The method is easily implemented using commercially available molecular modeling software. 相似文献
4.
Long bone growth is analyzed for 180 children from a Medieval population at Kulubnarti in Sudanese Nubia (550–1450 A.D.). A regional interpopulation comparison is made with growth data from Wadi Halfa in Lower Nubia, and an intrapopulation analysis is undertaken to assess diachronic changes in growth at Kulubnarti. Changes in growth patterns are interpreted in the context of mortality and morbidity profiles and relationships between the three variables are discussed. It is suggested that changes in the sociopolitical environment may have been responsible in part for altering levels of biological stress and impacting growth. 相似文献
5.
M. B. Dale 《Plant Ecology》1989,82(1):1-12
Cover-abundance estimates are commonly employed in phytosociological investigations to record the performance of species. Because the coded values are on an ordinal scale of measure, various authors have suggested that some transformation is necessary before such values can be used for classification and ordination. However, it is not clear that transformation is a sufficient treatment, and it would seem preferable to use ordinal data directly. In this paper we examine such direct use of partial rankings and show that several dissimilarity measures can be defined for this case without invoking any transformations. They include dissimilarity measures associated with various rank correlation measures and with distances between strings; all the measure are variant forms of Hausdorf's interset distance. Certain other kinds of data, such as those employing dominant and subdominant species and the dry-weight-rank estimation of biomass, are also on an ordinal scale and could be analysed using similar techniques.To illustrate the approach, a string dissimilarity measure is used to analyse a set of data from Slovakian grasslands which appear to reflect a simple gradient. The original data were recorded with 10 classes of performance and are analysed using hierarchical and nondeterministic, overlapping, classifications. 相似文献
6.
D. Chen 《Human Evolution》1989,4(1):73-86
In approaching the taxonomy of Neolithic Man and its phylogenetic relationship to Later Paleolithic Man and Modern Man in
China, the statistical methods used here are Penrose's shape distance and PCA (Principal Component Analysis). The scattergram
based on principal component scores, combines the dendrogram based on Penrose's shape distance, and takes the male taxonomy
into main consideration, but takes the female taxonomy — as a reference only because the differentiations in physical characteristics
among male populations generally are rather larger than those among the female populations. Thus according to this scattergram,
Neolithic Man in China can be divided into two large groups: the Northern China group, and the Southern China group. The theory
is that in Hengzhen there exist some blood mixtures between the Southern China Group and the Northern China Group (especially
the third subgroup) of Neolithic Man. Later Paleolithic Man of China — Liujiang and Upper-Cave Man — can also clearly distinguished
from the rest of Neolithic Man in China in the scattergram, and can be considered as two different local types of Later Paleolithic
Man. So-called “Negro-Australoid” racial traits can themselves be doubtlessly traced back to Later Paleolithic Man of China
— Liujiang and Upper-cave Man. These traits are the intrinsic characteristics of Neolithic Man in China and only then is there
slight difference in the extent of the manifestation of these traits in the population. 相似文献
7.
We analyzed bilateral finger prints of 3158 individuals from 13 Iranian populations of diverse origins, for digital patterns,
using the topological method. Some male/female differences, and a great deal of heterogeneity in interpopulational variation
was observed. Distance analysis, and the resultant dendrograms separated the populations studied, but the separation was not
in agreement with the known ethnohistory of this region. Comparison of the obtained results with those based on the traditional
methodology showed that the traditional methodology gives better results in measuring population distances. 相似文献
8.
H. Schöne 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1996,179(4):587-592
Honeybees returning from foraging trips were video-filmed while they walked through a narrow transparent gangway to reach the hive entrance. On their way they were presented with black-and-white gratings viewed underneath as well as to both sides of the gangway. Bees could exit the gangway through one of two or three side exits installed at different distances from the gangway entrance. In one set of experiments, the substrate on which the bees walked was moved either in the bee's direction or against it. In another set of experiments, the substrate was stationary, but the pattern was moved in one or the other direction. The bee's walking speed (WS) was evaluated from the video tapes. When the substrate moved against, or the pattern in the bee's direction, in either case decreasing the speed of pattern flow (PFS), the bees increased WS, and, at the same time, they preferred the more distant exit. When the substrate moved in, or the pattern against the bee's direction, thus increasing PFS, WS decreased and the bees preferred the nearer exit. These results suggest that the speed of optic flow controls the speed of locomotion and might therefore also serve for assessing the distance travelled.Abbreviations
PFS
pattern-flow speed
-
WS
walking speed
Dedicated to Hans-Jochen Autrum, editor emeritus, for help in giving birth to this and many other papers over very many years, often with criticism but nevertheless with encouragement and sympathy. 相似文献
9.
Hélène Déméné Nathalie Jullian Nelly Morellet Hugues de Rocquigny Fabrice Cornille Bernard Maigret Bernard P. Roques 《Journal of biomolecular NMR》1994,4(2):153-170
Summary The nucleocapsid protein of Moloney murine leukemia virus (NCp10) is a 56-amino acid protein which contains one zinc finger of the CysX2CysX4HisX4Cys form, a highly conserved motif present in most retroviruses and retroelements. At pH5, NCp10 binds one zinc atom and the complexation induces a folding of the CysX2CysX4HisX4Cys box, similar to that observed for the zinc-binding domains of HIV-1 NC protein. The three-dimensional structure of NCp10 has been determined in aqueous solution by 600 MHz 1H NMR spectroscopy. The proton resonances could be almost completely assigned by means of phase-sensitive double-quantum-filtered COSY, TOCSY and NOESY techniques. NOESY spectra yielded 597 relevant structural constraints, which were used as input for distance geometry calculations with DIANA. Further refinement was performed by minimization with the program AMBER, which was modified by introducing a zinc force field. The solution structure is characterized by a well-defined central zinc finger (rmsd of 0.747±0.209 Å for backbone atoms and 1.709±0.187 Å when all atoms are considered), surrounded by flexible N- and C-terminal domains. The Tyr28, Trp35, Lys37, Lys41 and Lys42 residues, which are essential for activity, lie on the same face of the zinc finger, forming a bulge structure probably involved in viral RNA binding. The significance of these structural characteristics for the various biological functions of the protein is discussed, taking into account the results obtained with various mutants. 相似文献
10.
One hundred and fifty four (86 male and 68 female) Punjabi infants residing in Chandigarh (India) were longitudinally measured
for head circumference at monthly age intervals during first year of life. The general pattern of growth of head circumference
was characterised by initial sharp rise followed by slow gain during second half of infancy. Beyond birth male infants, possessed
higher and statistically significant mean values than their female counterparts. The pattern-wise similarity between growth
curves plotted for Punjabi and Western infants, may be attributed to protective effects of breast feeding. Head circumference
velocity showed rapid deceleration immediately after birth up to about 4 months, thereafter, it declined slowly. Sex differences
in monthly growth rates were found to be statistically significant (p<0.05) at a few of the age intervals during first year
of life. 相似文献