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R L Jantz

Publications and source records attributed to R L Jantz.

At least 37 records · Page 2Linked to original sources
PubMed1990

Statistical assessment of population variability: a methodological approach.

We have implemented a multivariate statistical methodology to assess the degree and pattern of cranial variability in skeletal samples. Specifically, the method is designed to test whether variability in a skeletal sample exceeds "normal within-group variability" defined in the present instance as variability present among crania from a cemetery associated with a village. It involves comparing a covariance matrix derived from a sample of unknown composition to one representing "normal within-group variability." The method has been applied to two Plains Indian craniometric samples. The Leavenworth site (39CO9) represents the remnants of previously autonomous Arikara Indian villages devastated by epidemic diseases in the late 1700s. The Bad River 2 Phase is an archaeological designation grouping together closely related sites in the Bad-Cheyenne region of South Dakota dating from 1740-1795 AD. We were able to show substantial heterogeneity among crania from Leavenworth. District burial areas at Leavenworth account for some of the heterogeneity, supporting the notion that they represent an attempt to maintain former social distinctions. We were unable to differentiate among sites within the Bad River 2 Phase, suggesting that it is a valid biological unit.

Analysis of Variance↗
PubMed1990

Palm and sole interdigital ridge-count correlations.

Correlations among the twelve palm and sole interdigital ridge-counts were calculated for samples of Europeans of German, Austrian, Finnish and Polish ancestry, for Bantu speaking Black Africans from Angola and the Republic of South Africa, for Japanese and Tibetans and for Indians and Coloureds from the Republic of South Africa. Canonical correlation and factor analyses were used to discern patterning in the correlations. Generally, within palm and within sole correlations are stronger than palm-sole correlations. However, the results show an unequivocal positive relationship between palm and sole ridge-counts. A consistent feature was a stronger relationship of palm c-d counts to sole a-b counts. We suggest that this pattern of correlation may reflect early morphogenetic pattern formation prior to commitment of cells to hands and feet.

Africa↗
PubMed1990

Stature estimation from fragmentary femora: a revision of the Steele method.

The skeletal remains presented to forensic anthropologists are often fragmentary. Previously described methods of estimating stature from segments of long bones have not proved satisfactory because of the difficulty involved in identifying the precise anatomical landmarks by which they are defined. This study represents an assessment of the feasibility of stature estimation from fragmentary femora. A sample of 200 males and females, blacks and whites (total sample = 800), was obtained from the Terry Collection. New regression equations for the estimation of maximum femur length and stature from three well-defined and easy-to-measure segments of the femur are presented. This technique represents an improvement over methods currently in use for estimating stature from femur fragments; the location of the anatomical landmarks and the accuracy of the prediction are enhanced. The applicability of these formulae to a modern forensic sample is addressed with regard to secular trends in stature increase and changes in body segment proportions.

Anthropology, Physical↗
PubMed1985

Long bone lengths and gestational age distributions of post-contact period Arikara Indian perinatal infant skeletons.

Prenatal growth is adversely affected by poor socioeconomic conditions where disease and chronic undernutrition prevail. Premature and small-for-gestational-age births occur at higher frequency. Post-contact Arikara Indian populations of South Dakota experienced a rapidly changing and disruptive environment that included deterioration of the subsistence base and increased morbidity. This research tests resulting fetal growth effects through comparative analysis of two perinatal infant samples of the early (A.D. 1600-1733) and the late (A.D. 1760-1835) post-contact period. Perinatal infants recovered from late cemeteries include a higher percentage of smaller skeletons, as determined using long bone diaphyseal lengths, than is documented for the earlier time period. This contrast shows that it is possible to detect fetal growth differences in samples of archaeological context.

Embryonic and Fetal Development↗
PubMed1984

Long bone growth among Arikara skeletal populations.

Long bone growth variation among skeletal samples had had limited application to ecological studies of archaeological groups, in spite of its well-known sensitivity to health and nutritional status. In this study we examine long bone growth variation among ten samples of Arikara skeletal groups, all located in the Middle Missouri subarea of South Dakota and ranging in time from A.D. 1600 to 1832. The samples are analyzed by variant, an archaeological taxonomic unit below Tradition. Children's long bones between about 0.5 and 11.9 years of age were analyzed by means of regression using the model, bone length = b0 + b1 (age) + b2 (log10 age). The three variants, Extended Coalescent, Postcontact Coalescent, and Disorganized Coalescent, differ from one another with regard to health and nutritional status. Extended Coalescent groups probably experienced periods of undernutrition due to unfavorable climatic conditions prevailing at the time. Postcontact Coalescent groups experienced more favorable health and nutrition due to improved climatic conditions and introduction of the horse. Disorganized Coalescent groups were exposed to undernutrition and high levels of morbidity, due to introduction of epidemic diseases, depopulation, and intertribal conflict. Analysis of slopes shows significant heterogeneity among variants for humerus, radius, and tibia, but not femur. In general, the Postcontact Coalescent is characterized by slighter greater rates of increase with age and longer bone lengths for each age than is Extended Coalescent. Disorganized Coalescent exhibits lower rates of increase, particularly in later childhood, with shorter bone lengths in late childhood.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1984

Genetic and environmental variation of ridge-counts on fingers, palms, soles and toes: a twin study.

A multivariate procedure for estimating heritable components from twin data was applied to ridge counts obtained from the entire dermatoglyphic system. Covariance matrices of MZ and DZ within-pair differences were used to estimate genetic correlation matrices for 20 finger ridge counts, 6 palmar interdigital counts, 20 toe counts, 4 hallucal counts, and 6 sole interdigital counts. The proportion of genetic variation was found to be greater in ridge counts of patterns than in ridge counts of interdigital areas. On digits, finger counts are more highly heritable than toe counts. Each of the dermatoglyphic areas yielded several independent genetic components, ranging from general to specific. Environmental variation was found to be local and to frequently involve reciprocal interaction between twin pairs.

Dermatoglyphics↗
PubMed1983

A comparison of dermatoglyphic methodologies in population studies.

Use of dermatoglyphics in population studies has been marked by a great deal of methodological variation among investigators. We compare various dermatoglyphic approaches using data derived from four groups in the Kumaon region of India. Dermatoglyphic data included ridge-counts and other quantitative variables, and the classification systems of Cummins and Midlo and Penrose and Loesch. Results were evaluated against anthropometric and serological relationships. No clearly superior approach emerges, although it is generally true that palmar variables exhibit more intergroup heterogeneity than digital variables and produce more reasonable results than the other approaches. The conventional method of treating ridge-counts, that of choosing the larger of the two counts, was the most unsatisfactory of the quantitative approaches, leading to the recommendation that both radial and ulnar counts be retained. We conclude that environmental variation may contribute substantially to intergroup variation.

Anthropometry↗
PubMed1983

Formation of the permanent dentition in Arikara Indians: timing differences that affect dental age assessments.

This report concerns one problem encountered with application of American white dental formation standards to age assessment of sub-adults of archaeological context. Dental ages for eight mandibular permanent teeth and maxillary central and lateral incisors of Arikara Indian immature skeletons were determined according to degree of crown or root mineralization. Ages assigned to the various teeth of the same individual were compared. They showed similarities as well as patterned differences. First premolar, second premolar, and mandibular incisor ages closely approximated one another. In relation to this complex, dental ages for maxillary incisors and mandibular second molars were older by 0.5 to 1.1 years. Developmental ages assigned to individuals on the basis of third molars showed relative advancement by more than 2 years. The systematic occurrence of these observations reflects more than just individual variability; it shows the presence of population differences in tooth-formation timing. Timing differences complicate assessment of dental ages needed for growth or demographic studies.

Aging↗
PubMed1982

Intercemetery morphological variation in Arikara crania from the Mobridge Site (39WW1).

Multivariate analysis is used to examine intrasite variation in cranial morphology in the Mobridge Arikara skeletal collection. The site included three spatially distinct burial areas. The burial areas (features) are defined according to geographic location. Feature 1 is a small hill west of the village. Feature 2 is a large, long hill 200-300 yards south of the village. Feature 3 is a small knoll 100 yards south of Feature 1. The internal chronology of Mobridge has not been established with precision, but order has been postulated based on archeological data. Previous researchers have considered area 2 to be later than areas 1 and 3. Significant morphological heterogeneity exists between areas. Sample differences indicate that specific features were used by temporally distinct populations. The archaeologically proposed temporal ordering of the cemeteries is supported by osteological evidence.

Analysis of Variance↗
PubMed1982

Dermatoglyphics in seizure disorders.

A dermatoglyphic study of 197 adult Caucasian males with a confirmed diagnosis of epilepsy was carried out in an attempt to ascertain possible associations between aberrant dermatoglyphic and seizures and to estimate their diagnostic usefulness. Qualitative and quantitative fingertip and palmar dermatoglyphic traits were evaluated. The data were analyzed by etiology seizures. Previous studies and our own earlier data (Schaumann 1979) analyzed by univariate statistical methods indicated the presence of some dermatoglyphic deviations in patients with epilepsy, suggesting the existence of a genetic predisposition to seizures of various etiologies. In the present study, a multivariate analysis was employed on an enlarged patient sample. Three variables were found to be significant: an increased main line index on the right palm (p less than .01) and decreased a-b ridge counts on both left and right palms (p less than .001). Tests of the eigenvalues showed only one value to be significant and accounting for 71.8% of the intergroup variation.

Adult↗
PubMed1981

A multivariate analysis of temporal change in Arikara craniometrics: a methodological approach.

We have examined temporal changes in the cranial architecture of Arikara Amerindians from five archaeological sites in South Dakota which span a time period of approximately 230 years (ca. A.D. 1600-1830). We have utilized a multivariate statistical method based on a principal components analysis of the pooled within-groups correlation matrix rather than the more traditional methods of ascertaining morphological relationships, e.g., discriminant functions, Mahalanobis' D2, or Penrose's Size and Shape. Our component structure, based on a regional sample and the mathematically simpler principal components analysis, is very similar to the factor structure obtained by Howells (1973) using a world-wide sample and factor analysis proper. This supports the notion of the "universality" of cranial structure. An axis of temporal variation was introduced into the component space by means of multiple regression. This analysis indicates that a substantial portion of the intergroup variation is temporal in nature and the systematic temporal changes occur along the facial height, transverse frontal flatness, and frontal profile flatness components. Earlier analyses of the same material by more conventional methods either did not detect the temporal trends at all or failed to isolate the specific nature of the temporal changes. The success of the present analysis attests to the value of examining morphological relationships be means of principal components.

Cephalometry↗
PubMed1980

Components of racial variation in finger ridge-counts.

Principal components analysis was used to evaluate finger ridge-count variability as an indicator of genetic relationships between populations. The analysis was carried out on American White, American Black and African Black samples, each including both sexes. Each individual is represented as a vecotr of 20 counts, a radial and an ulnar count for each digit. No assumptions were made prior to analysis concerning the number of meaningful components, and all were examined sequentially. The first five eigenvectors extracted from the within-groups correlation matrix have loadings very similar to those previously described by Roberts and Coope ('75). However, it is the component scores derived from the sixth eigenvector which show the most marked variation, accounting for 45% or more of the D2 in all Black-White comparisons. A number of other components also show significant intergroup heterogeneity, but they often do not accord with what is known of the genetic relationships between the populations. Apparently a large amount of ridge-count variation is not genetically meaningful, at least as far as these populations are concerned.

Africa, Western↗