Multivariate analysis of Gigantopithecus mandibles

Multivariate analysis of measurements of the teeth and mandibles of Gigantopithecus species has been conducted, using several methods. Results indicate Gigantopithecus is an aberrant form, less related to australopithecines and gorillas than the latter are to each other. Gracile and robust australopithecines differ considerably more than do male and female gorillas.     

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.     

Interspecific and intraspecific relationships between tooth size and jaw size in primates

The association between mandibular robusticity, postcanine megadontia, and canine reduction in hominins has led to speculation that large and robust jaws might be required to spatially accommodate large canine and molar teeth in hominins and other primates. If so, then variations in mandibular form that are generally regarded as biomechanical adaptations to masticatory demands might instead be incidental effects of functional requirements of tooth support. While the association between large teeth and deep, robust jaws in hominins is well known, the relationship between tooth size and jaw size has not been systematically evaluated in a comparative sample of primates. We evaluate the relationships between molar tooth size, canine tooth size, and mandibular corpus and symphyseal dimensions in a sample of adult anthropoids in interspecific (n=84 species) and intraspecific (n=36 species) contexts. For intraspecific comparisons, tooth size and jaw size are correlated, but for a majority of species this is a function of sexual size dimorphism. Interspecific comparisons lend little direct support to the hypothesis that jaw breadth directly covaries with molar tooth breadth, but they do support the hypothesis that mandibular depth is associated with canine tooth size in males. The latter observation suggests that if there is a causal association between canine size and mandibular depth, it is subject to a threshold effect. In contrast, neither corpus nor symphyseal robusticity, measured as a shape index of breadth/height, are correlated with tooth size. Our results suggest that further studies of the relationship between tooth size and corpus morphology should focus on tooth root size and corpus bony architecture, and that species-specific factors should have a strong impact on such relationships.     

A metrical comparison of maxillary first premolar form

In a study of maxillary right first premolar morphology, multivariate analysis showed varying degree of separation between four human ethnic groups depending upon the actual metrical profile included in the analysis. Such ethnic discriminations were not possible from visual inspection or univariate analysis of individual crown diameters. Although the interpretation of such ethnic contrasts remains obscure, this study demonstrated the potential of multivariate statistical techniques in the investigation of odontometric data.     

Patterns of approximal wear in cheek teeth of a Romano-British population

The approximal surfaces of premolars and molars of 376 adult British-Romano skulls were examined for wear facets. The type of wear was designated as convex, concave, sigmoid, or flat, and the degree was categorised on a three-point scale. Concave wear facets were more frequently seen in the older age groups, but the type of wear was similar on right and left sides. Taking all teeth together or as individual tooth types, concave wear was significantly more likely on mesial rather than distal surfaces. The degree of wear was age related and similar on right and left sides in both males and females. It is suggested that the distribution of concave facets may be related to movements between adjacent teeth.     

Pliocene hominid mandibles from the Hadar formation,Ethiopia: 1974–1977 collections

The Pliocene hominid mandibles of A. afarensis from Hadar, Ethiopia are described anatomically.     

A test of the child replacement hypothesis: nineteenth century Massachusetts

Child mortality experiences may affect subsequent fertility of couples by exerting a physiological effect, influencing length of birth, interval, or a replacement effect, in which couples continue to procreate in an attempt to reach a desired number of surviving offspring. Where biological constraints are potentially important, however, it may be difficult to distinguish between purely physiological and purely behavioral components of the process regulating production. Natural spacing of births and onset of sterility may be affected by health and diet and prior childbearing and breastfeeding practices. Biological pressures can, in turn, be infuenced behaviorally both by social custom and individual choice. Studies of 126 families in 19th century Massachusetts show that reduction in infant mortality is not a prerequisite for onset of family limitation. Results for the study population did not exhibit a relationship between parity progression ratios and the experience of child mortality, consisten with the child replacement hypothesis. 1 factor involved may be the parent's expectations of more than the desired number of children because of imperfect contraceptive technology at the time. Preference for the sex of children also may weaken overall replacement effect, since the death of a child of "undesired" sex will not be replaced. The cohort age-specific fertility patterns indicate that a reduction in overall fertility level in the communities studied was parity-dependent and directed at stopping childbearing at some given range of family size. At any rate, parents are not passive participants in a natural regime of births and deaths. While child replacement may be present in some societies, it is relatively inefficient and perhaps infrequent.     

Congenital defects of the upper lateral incisors: Multivariate analysis of measurements of the other teeth,the superior arch,head and face

The survey of a French male population allowed us to ascertain 75 propositi with one or two missing ULI, 59 propositi with one or two reduced ULI and 99 controls on whom measurements (mesiodistal and buccolingual diameters) of all teeth of the superior arch are available. Principal Component Analysis gave a first estimated principal component highly correlated with each of the dental measurements or arch measurements. This size factor was eliminated by observing the plane of the second and third principal components. Strikingly different clusters of MD diameters or BL diameters were observed for the controls, the propositi missing one or two of the ULI and the propositi with reduced ULI. For the controls, the arch length is correlated with the MD molar diameters and the MD incisor diameter, the arch width being isolated from the other measurements. For the propositi with missing ULI, among the dental measurements the MD and BL diameters cluster, the arch length is isolated as are the arch widths. For the propositi with reduced ULI, the arch length is closer to the dental measurements while the widths, especially the first one, are isolated. The best discriminant measurements are the diameters of the first premolars and the canine, the first arch width and the arch length. Among controls, the arch is narrowed and shorter for the propositi with absence and wider for the propositi with reduction. Teeth measurements are always smaller in propositi.     

Essay review: Science and politics in the nineteenth century

Essay review: Science and politics in the nineteenth century     

A comparison of the position of the mental foramen in Chinese and British mandibles

The antero-posterior position of the mental foramen was studied in 68 Chinese and 44 British skulls of known or calculated age at death. All skulls showed low pre-mortem tooth loss and had a good occlusion. The position of the foramen was related to the body of the mandible as well as to the standing mandibular teeth using two previously published methods. There was no significant difference in the size of the Chinese and British mandibles. There was a significant difference between the two groups when measurements relating the foramen to the body of the mandible (symphysis menti) were considered, the foraminal position being more distal in the Chinese group. The modal position of the foramen in the Chinese sample was along the long axis of the second premolar, whereas in the British sample it lay between the apices of the first and second premolar. The foraminal position apparently moved distally in both groups with age and this was likely to be associated with mesial tooth drift and age-related attrition.     

Adelchi Negri and Schools of General Pathology in Italy between the end of the nineteenth and beginning of the twentieth century

The long lasting scientific collaboration of Adelchi Negri with Camillo Golgi in the Laboratory of General Pathology and Histology of Pavia began in 1898–99, when he was still a medical student, and at about the time basic knowledge about human malaria transmission cycle (to which Golgi himself had given important contributions) was completed. On the occasion of the 100^th anniversary of the discovery of Negri bodies, this article provides a short overview of the scientific and cultural context in whichNeurocytes hydrophobiae hypothesis matured. To the same intent and purposes, this article also delineates some of the important scientific achievements in the field of General Pathology by Negri’s contemporaries, reflecting both the influence of the two great pioneers in the field (Bizzozero and Golgi), and the close contact with European science in the 1890’s to the end of the first World War, when biological science in Italy entered a new crisis.

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Adelchi Negri e le Scuole di Patologia generale nel passaggio dall’Ottocento al Novecento

Riassunto  La lunga collaborazione scientifica di Adelchi Negri con Camillo Golgi, nel Laboratorio di Patologia generale ed Istologia di Pavia, ebbe inizio nel 1898–99, quando questi era ancora studente di Medicina, e la conoscenza di base sul ciclo di trasmissione della malaria nell’uomo (alla quale lo stesso Golgi aveva dato importanti contributi in studi pionieristici) era completata. In occasione del Centenario della scoperta dei Corpi del Negri, questo articolo offre una rassegna sintetica del contesto scientifico-culturale in cui maturò l’ipotesi delNeurocytes hydrophobiae come agente causale della rabbia. Con questo intento e per lo stesso scopo, questo articolo traccia anche alcuni degli importanti raggiungimenti scientifici nel campo della Patologia generale da parte dei contemporanei di Negri, nei quali è rinvenibile, sia l’influenza dei grandi pionieri della disciplina (Bizzozero e Golgi), sia lo stretto contatto con la scienza europea, tra il 1890 circa e la fine della prima guerra mondiale, allorché la scienza biologica italiana entrò in una nuova crisi.

     

A multivariate study of the relationship between the genetic code and the physical-chemical properties of amino acids

Summary The 20 naturally occurring amino acids are characterized by 20 variables: pK_{NH 2}, pK_COOH, pI, molecular weight, substituent van der Waals volume, seven¹H and¹³C nuclear magnetic resonance shift variables, and eight hydrophobicity-hydrophilicity scales. The 20-dimensional data set is reduced to a few new dimensions by principal components analysis. The three first principal components reveal relationships between the properties of the amino acids and the genetic code. Thus the amino acids coded for by adenosine (A), uracil (U), or cytosine (C) in their second codon position (corresponding to U, A, or G in the second anticodon position) are grouped in these components. No grouping was detected for the amino acids coded for by guanine (G) in the second codon position (corresponding to C in the second anticodon position). The results show that a relationship exists between the physical-chemical properties of the amino acids and which of the A (U), U (A), or C (G) nucleotide is used in the second codon (anticodon) position. The amino acids coded for by G (C) in the second codon (anticodon) position do not participate in this relationship.     

Dimensional characteristics of the Filipino dentition

This study concerns odontometric analysis of the Tagalog Filipinos in Manila, Philippines. Mesiodistal and buccolingual dimensions of the permanent dentition, a total of 56 variables, were studied in 100 males and 152 females. Results showed that their absolute tooth size was small. Relative tooth size, however, seemed to reflect their Southeast Asian Mongoloid origin. From univariate analysis, considerable male-female differences were shown in most of the variables studied. When correlation effects among the teeth were held constant through multivariate analysis, male-female distance was found to be small and substantial overlapping of the two multivariate distributions was evident. Only four variables could be shown by stepwise discriminant analysis to contribute significantly to the distance. Even the mandibular canine, as the strongest discriminator, could only account for 16.4% of the total multivariate distance. These contrasting findings for sex dimorphism in a set of teeth taken singly and taken jointly indicate that there are factors other than the teeth themselves that are expected to play important roles in determining overall male-female size differences in the set of teeth, and that these differences may not be as clear-cut as univariate analysis suggests.     

On the surgical treatment of facial paralysis in the early nineteenth century

The treatment of facial paralysis is generally considered to have been nonsurgical until the end of the nineteenth century. However, the authors discovered recently that already in the 1840s the celebrated German facial reconstructive surgeons Dieffenbach and von Langenbeck applied the technique of subcutaneous myotomy to healthy facial muscles to reestablish balance in the chronically paralyzed faces of their patients. They performed their operations at a time when anesthesia, asepsis, antisepsis, and antibiotics had not yet been introduced into surgery. It is concluded that Dieffenbach and von Langenbeck were the first, in recorded history, to develop a surgical way to treat irreversible facial paralysis. As their principles are still being used in surgical practice, they cannot be regarded as antiquated, which illustrates the difficulties that reconstructive surgeons still experience in the treatment of irreversible facial paralysis.     

Isozyme and plastid DNA assessment of pedigrees of nineteenth century potato cultivars

Summary Isozyme and ctDNA RFLP patterns were determined for ten historically important potato cultivars (Solanum tuberosum ssp. tuberosuni) in order to relate and confirm their pedigrees. Isozyme polymorphism was detected at 11 of 13 loci examined, whereas only T-type cytoplasm, the predominant ctDNA of S. tuberosum ssp. tuberosum, was observed. Isozyme analysis indicated that potato cultivars previously presumed to be derived from open-pollinated berries of Garnet Chili and Early Rose were in fact the result of hybridizations. In addition, putative pedigrees of Irish Cobbler, White Rose, and Bliss Triumph were not supported. Garnet Chili, the first derivative of Rough Purple Chili, carries allozmyes at Mdh-1 and Pgm-2, which supports the Chilean origin of Rough Purple Chili. The identical ctDNA pattern among the cultivars may indicate a common maternal lineage that traces through Garnet Chili to Rough Purple Chili. The allozyme frequencies estimated from these cultivars provide a base from which subsequent introductions of Solanum species into the ssp. tuberosum gene pool can be assessed.Journal Article No. 000123