A comparison between the mandibles of Romano-British and nineteenth century periods

The mandibular and tooth dimensions were measured on a total of 210 specimens from Romano-British, Anglo-Saxon and nineteenth century times. The measurements were subsequently compared by means of univariate and multivariate techniques. The results indicated that the mandibular dimensions decreased more than tooth dimensions between Romano-British and nineteenth century periods, but did not discriminate whether such mandibular changes occurred primarily in the ramus or corpus of the mandible.     

Modern human metrical variation in the first three manual rays

This study utilizes radiographic samples of white, black. Mexican-American, and Asian males and females from the Ten State Nutrition Survey to examine the degree and pattern of variation seen in measurements of bones from the three radial hand rays. Pattern profile analysis is used to portray graphically the intersample differences for 44 length and width variables. This technique allows a visual assessment of intersample differences and extends results of statistical analyses. Base widths serve best in separating male and female groups. Males have a longer first ray with respect to the second ray and a longer first proximal phalanx compared with the second proximal phalanx than do females. Certain ray III variables seem to hold the most promise for separating samples within one sex. Correlation of pattern profile curves demonstrates that within nonwhite ethnic samples the shape of male and female curves is similar when plotted against the white reference samples. Coefficients of variation for the large white samples are highest for mid-widths and tuft widths of distal phalanges and lowest for lengths and base widths of proximal phalanges II and III. While some of the variation between groups may serve to distinguish populations and may relate broadly to evolutionary history, it is difficult to show clear functional correlates for the majority of the variation detected. It is suggested that hypotheses relating morphology of hominid hands to hand function and behavior should consider the extent of modern human hand bone variation.     

Reduction of maxillary molars in Homo sapiens sapiens: a different perspective.

Crown and cusp areas, and buccolingual and mesiodistal diameters of maxillary molars of complete upper tooth rows (30 males, 30 females) were analysed in order to quantify changes in size and shape from the first to the third molar. Uni- and multivariate analyses revealed the mesial cusps, in particular the protocone (mesiolingual cusp), to be more stable than the other cusps. Although there is a gradient in size from the first to third molar, shape changes were found to be marked. Overall, the findings are in keeping with the field theory and the hypotheses of environmental constraints on later developing teeth. However, not all of the results could be entirely explained by these concepts. Functional aspects seem to account for the relative stability of the protocone and the buccolingual crown diameter. It appears that this functional complex is relatively stable despite the overall reduction of tooth size, which is probably secondary to processes occurring in the jaws and the cranium. This finding may have implications for studies on tooth reduction between populations of different time periods.     

Shape components of the maxillary molars in Australian aboriginals

Principal components analysis was used to quantify the variability in crown outlines of maxillary molars in Australian Aboriginals. The outlines were measured by 36 radii from the central pit to the crown periphery. The first component, responsible for over half of the total variance, was concerned with general crown size. Four remaining components were retained to indicate sources of variability resulting from contrasting degrees of development or reduction of different crown components. Shape changes from the first to third molars were identified with components representing overall size reduction, diminution of the hypocone, and metacone elements and mesiodistal compression. An anteroposterior gradient along the molar series in average scores and variances for all components resulted from the progressive reduction of distal crown elements, increasing mesiodistal compression, and greater morphological variation.     

Cranial capacity/cranial base relationships and prediction of vault form: A canonical correlation analysis

Canonical correlation analysis was used to test an hypothesized morphological relationship between vault form and cranial capacity relative to length of the chondrocranium. Ninety-five adult male Czech skulls were measured for vault form expressed as length, width and height of the brain case; the chondrocranium was represented by nasion-basion and basion-opisthion lengths. In terms of explained variation, the first and most important dimension of covariation between vault and chondrocranial variables was size. The second most significant dimension of covariation expressed the hypothesized shape relationships—i.e., overall size being equal, the shorter the chondrocranial base relative to cranial capacity, the shorter and wider the vault. Furthermore, the competing hypothesis that vault form is determined by facial length proved untenable since facial length was predictive of vault shape only when measured as prosthion-basion, a measure that incorporates basal length. When corrected for basal length, facial length is unrelated to vault form. The results are consistent with the assumption that phylogenetic and microevolutionary trends toward brachycephaly in man stem from changes in the relationship between two components of skull growth, the chondrocranial base and the brain.     

A study of the taxonomic significance of the dental arch.

Sixteen dimensions were measured from the maxillary and mandibular dental arches of different ethnic groups of man, apes and monkeys. Multivariate analysis showed that discrimination was possible among the ethnic groups of man on the one hand and between the ape and monkey samples on the other. Nevertheless, the actual degree of discrimination between the primate samples depended upon whether the maxillary or mandibular arch dimensions were analysed. Furthermore, subsequent inclusion of the dental arch dimensions of fossil hominoid samples into the analysis confirmed the taxonomic significance of the dental arch, although its importance must await the acquisition of the more non-human primate data.     

Quantitative hair form variation in seven populations

Although hair form has received much attention in the past, it has rarely been studied systematically, and never using direct curling variables. In the present study, seven groups were scored on eight variables, including four newly-devised curling variables. These data were analyzed using univariate and multivariate techniques to give information about the population relations and mechanisms of hair form. “Racial” groups were separated using a principal components analysis. African and Melanesian populations were shown to have significantly different quantitative hair form traits, especially in regard to their regularity of curvature. The physiological, environmental, and genetic factors contributing to hair form variation are discussed.     

A rolling circle model of the in vivo replication of bacteriophage phiX174 replicative form DNA: different fate of two types of progeny replicative form

In a preceding paper (Schröder and Kaerner, 1972) a rolling circle mechanism has been described for the replication of bacteriophage φX174 replicative form. Replication involved nicking and elongation of the viral (positive) strand component of the RF molecule resulting in the displacement of a single-strand tail of increasing length. The synthesis of the new complementary (negative) strand on the single-strand tails appears to be initiated with considerable delay and converts the tail into double-stranded DNA. Before the new negative strand is completed the replicative intermediates split into (I) a complete RF molecule containing the “old” negative and the new positive strand, and (II) a linear, partially double-stranded “tail” consisting of the complete old positive strand and a fragment of the new negative strand.The present study is concerned with the fate during RF replication of these fragments of the rolling circles. Those RFII molecules containing the old negative strands appear to go into further replication rounds repeatedly. Some of the tails were found in the infected cells in their original linear form. “Gapped” RFII molecules, which have been described earlier by Schekman and co-workers (Schekman &; Ray, 1971; Schekman et al., 1971), are supposed to originate from the tails of rolling circle intermediates by circularization of their positive strand components. Evidence is provided by our experiments that even late during RF replication these gaps are present only in the negative strands of RFII. Appropriate chase experiments indicated that the tails finally are converted to RFI molecules. Progeny RFI molecules could not be observed to start new replication rounds under our conditions although we cannot exclude that this might happen to some minor extent.The results presented suggest that the master templates for RF replication are the first negative strands to be formed, rather than the parental positive strands.     

Functional aspects of primate pelvic structure: A multivariate approach

This study aims to clarify the relationship of primate bony pelvic structure to locomotor habit. As with most of the postcranial skeleton, the pelvic bones of species within the Ceboidea and the Cercopithecoidea are remarkably similar visually except for variations in size. Yet there are substantial differences in locomotor pattern between the species in these taxa. I performed canonical analyses on a sample of 17 pelvic variables describing 22 primate species of the Ceboidea, the Cercopithecoidea, and the Hominoidea to discover which variables were significant in separating them into groups. In both analyses there was good separation of major taxa and additional separation of groups that differed in locomotor habit. The separation of colobine from cercopithecine monkeys was particularly consistent. In the analysis, including all 22 species, the variables given particular weight by the canonical analysis were the same as those traditionally used by anatomists for the same purpose. Specifically, breadth of the ischial tuberosity (reflecting presence or absence of ischial callosities) separated the Old from the New World monkeys. Breadth of the iliac tuberosity, in which man and to some extent other hominoids differ from other primates, and ilium height, in which man differs from other primates, were significant. Sagittal diameter of the pelvis was also substantially weighted. Having established that the technique would select variables of anatomical significance, the same method was applied to a study of monkeys only where the characteristics that differ between groups are not well established. Breadth of the ischial tuberosity was again important in separating the Ceboidea from the Cercopithecoidea. Discrimination of locomotor groups within these large divisions was brought about mainly by ischial length and the sagittal diameter of the pelvis. In studying these variables and their relationship to size in greater detail, it was found that among cercopithecoid monkeys, the colobines showed relatively lower values than did cercopithecines for both these dimensions. Atelines showed low values for ischial length but high values for the sagittal pelvic diameter. Biomechanical explanations of these observations are suggested.     

Zonation of submerged macrophyte vegetation in Lake Kariba,Zimbabwe and its ecological interpretation

The submerged vegetation of Lake Kariba is described in relation to degree of slope (lake morphometry), depth and light transparency. The direct gradient analysis technique — canonical correspondence analysis and the TWINSPAN classification programs were used to analyse the data set. The western end of the lake with low transparency has a low species diversity (with Vallisneria aethiopica dominating). Species diversity increases with increased transparency in the other parts of the lake. The classification revealed monospecific communities for all species as well as mixed communities with Lagarosiphon as the associate species with the broadest distribution. The ordination revealed a first axis strongly related to depth and transparency gradients and the second axis related to slope. Vallisneria aethiopica has a growth form adapted to grow in shallow areas subjected to wave action. Potamogeton octandrus also growing in shallow areas is restricted to sheltered areas. Lagarosiphon ilicifolius precluded from the shallow exposed areas grows at medium depth but has a growth form adapted to tap light at the surface. Najas pectinata and Ceratophyllum demersum are adapted to grow in deep water.Abbreviations CCA Canonical correspondence analysis     

Purification of new calcium activated protease (low calcium requiring form) and comparison to high calcium requiring form

A new calcium activated protease which requries low concentration of calcium was purified to almost homogeneity from porcine heart muscle. The protease was composed of two polypeptide chains of approximately 90 K and 30 K. The 90 K subunit was larger than the large subunit of the high calcium requring form of calcium activated protease, therefore we concluded that the low calcium requiring form is different from the high calcium requring form and its auto-digested protease. The low calcium reqiring form of calcium activated protease was also activated by manganese and balium, and was very stable even at pH 9.0     

Morphological and metrical comparison of San and Central Sotho dentitions from southern Africa

Comparative morphological and metrical study of San and Central Sotho dentitions indicates that the teeth of the two samples are significantly different from one another. The San dental complex contains traits that add mass to the occlusal surface of microdontic dentitions: moderate low-grade UI1 (13.5%) and UI2 shoveling (24.7%), high Bushman canine (43.1%), fairly low UM2 hypocone reduction (23.3%), high UM2 cusp 5 (55.6%), high LM1 cusp 7 (35.2%), LM1 distal trigonid crest (7.1%), and LM2 deflecting wrinkle (5.3%), lack of reduction of LM1 and LM2 cusp number, in the presence of very low UM1 Carabelli's trait (6.7%) and high LM2 Y-groove (86.3%). Culturally, males occasionally exhibit filed UI1 and females are missing LI1. Conversely, mesodontic Central Sotho dentitions display a more simplified morphology, with the exception of moderately high incidence of UM1 Carabelli's trait (41.0%) and very high LM1 cusp 7 (71.3%). Discriminant analysis of mesiodistal and buccolingual diameters and tooth crown surface area data for the left maxillary teeth supports classification of San dentitions as microdont and Central Sotho dentitions as mesodont. Additionally, metrical analysis indicates that San teeth are more sexually dimorphic than are those of Central Sotho.     

以林相图为基础的不同取样方式对植被排序分析结果的影响

以6种不同方式对林相图中同一样带取样,采用CA、DCA和CCA 3种排序方法,研究了取样方式对排序轴的解释效果、物种与环境因子、环境因子之间、环境因子与坐标轴之间关系的影响.结果表明,样方大小和形状的变化在不同程度上改变了排序结果.大样方和长方形样方都增强了排序轴的解释效果,并对双序图中稀有种、独特种的位置有较大的影响;环境因子中土壤因子对样方的大小和形状都很敏感,坡度、经纬度只对样方大小敏感,坡位、海拔、温度和降水则对样方形状敏感;随着样方面积的增加,海拔、温度和降水的作用降低,而坡向的作用增加.     

The genetics of shovel shape in maxillary central incisors in man.

From dental casts of 94 parent-offspring and 127 full-sib pairs, sampled from two Chilean populations, shovelling indices are computed to measure the degree of shovelling of maxillary central incisors quantitatively. Genetic correlations are computed to determine the role of genetic factors in explaining the variation in this trait. Assuming only hereditary factors to be responsible for the transmission of shovel shape, 68% of total variability is ascribed to the additive effect of genes.     

Tooth loss and tooth retention in a multitribal group of Bantu-speaking South African blacks: A study on 500 dry mandibles

Tooth loss and tooth retention in adult South African Bantu-speaking Negroes were studied from data derived from 500 dry mandibles. The tribe, sex, and stated age of the specimens were available. Mandibles were equally distributed over the third to seventh decade of life. The presence of dental units was recorded and analysed within and between decade age groups. The mandibles carried a total of 5,459 dental units. Between the third and fourth decades of life and between the sixth and seventh decades, the reduction of the frequency of dental units was mild and statistically not significant. It was, however, severe and significant between the fourth and fifth, and the fifth and sixth decades. In the third-decade group, most teeth were found in the anterior region with a tendency to diminish in number posteriorly. After the third decade there was a definite persistence of first premolars and canines with significant tendency toward loss of teeth anterior and posterior to them. Only the incisors and third molars showed significant reduction in number from the third to the fourth decade. The reduction of all teeth was statistically significant later, until the sixth decade of life. Although there was loss of teeth from the sixth to the seventh decade, it was not significant for any of the homologous dental units. There is a possibility that some dietary differences existed between the older subjects (50–70 years old) and the younger ones (20–49 years old) which may have had some influence on the results.     

An analysis of cercopithecoid odontometrics. I. The scaling of the maxillary dentition.

The relations between two tooth indices, post-canine area and incisor width in the upper jaw, and three variables, diet, body weight and body weight dimorphism, were examined separately for the males and females of 29 cercopithecoid species. Each species was assigned to one of three diet classes (folivore, frugivore, omnivore). Data on the other variable consisted of species means (log-transformed) obtained from published sources. The analytic techniques used were bivariate and multiple regression, the tooth indices being the dependent variables. All tooth indices scaled isometrically within diet classes, and all except female incisor width scaled with positive allometry across diet classes. In both sexes, the body weight adjusted mean incisor width of folivores was significantly smaller than that of either frugivores or omnivores. In the females, the body weight adjusted mean post-canine areas did not differ significantly across diet classes, while in the males the omnivores had a larger body weight adjusted mean post-canine area than either the folivores or frugivores. Female post-canine area was the only tooth index for which body weight dimorphism was a significant predictor. Extrapolations of these findings to other extant and to fossil primate species are discussed.