To investigate the determinants of low birth weight in infants born to adolescent mothers, we studied the obstetric population attended at the Maternity Hospital of Lima, Peru. From this population, 1256 gravidas, ranging in age from 12 to 25 years, volunteered to participate in this study. Anthropometric and biochemical measurements were used to evaluate the nutritional status and physiological maturity of the mother and newborn. For analytical reasons the young teenaged mothers (less than 15 years) were classified as either still-growing or having completed their growth, depending on their height relative to their parents' height. Similarly, the young teenagers were classified as either gynecologically immature or gynecologically mature depending on whether their gynecological age was less than or greater than 2 years. Our results indicate that young still-growing teenagers, even when matched for nutritional status, have smaller newborns than adult mothers. The data also demonstrate that maternal gynecological age per se does not affect prenatal growth. As inferred from multivariate analyses, it appears that the reduction in birth weight among young teenagers can be explained in part by a decreased net availability of nutrients resulting from the competition for nutrients between the mother's growth needs and the growth needs of her fetus and by an inability of the teenage placenta to maintain placental function adequately for active fetal growth.

The biological affinities of the ancient Egyptians were tested against their neighbors and selected prehistoric groups as well as against samples representing the major geographic population clusters of the world. Two dozen craniofacial measurements were taken on each individual used. The raw measurements were converted into C scores and used to produce Euclidean distance dendrograms. The measurements were principally of adaptively trivial traits that display patterns of regional similarities based solely on genetic relationships. The Predynastic of Upper Egypt and the Late Dynastic of Lower Egypt are more closely related to each other than to any other population. As a whole, they show ties with the European Neolithic, North Africa, modern Europe, and, more remotely, India, but not at all with sub-Saharan Africa, eastern Asia, Oceania, or the New World. Adjacent people in the Nile valley show similarities in trivial traits in an unbroken series from the delta in the north southward through Nubia and all the way to Somalia at the equator. At the same time, the gradient in skin color and body proportions suggests long-term adaptive response to selective forces appropriate to the latitude where they occur. An assessment of "race" is as useless as it is impossible. Neither clines nor clusters alone suffice to deal with the biological nature of a widely distributed population. Both must be used. We conclude that the Egyptians have been in place since back in the Pleistocene and have been largely unaffected by either invasions or migrations. As others have noted, Egyptians are Egyptians, and they were so in the past as well. o 1993 Wiley-Liss, Inc.A sense of one's biological heritage can easily transcend the familial and spill over into feelings of "racial" identity. These in turn lead all too quickly to attempts to bolster feelings of individual worth by invoking the collective reinforcement of "racial" pride. This was a favorite ploy of advocates of differential "racial" rank in the recent past. One of the clearest statements attributing merit not to individual achievement but to group membership was made by the former chairman of the Department of Psychology at Columbia University, Professor Henry E. Garrett, who admonished that: "No matter how low (in a socioeconomic sense) an American white may be, his ancestors built the civilizations of Europe; and no matter how high (again in a socioeconomic sense) a Negro may be, his ancestors were (and his kinsmen still are) savages in an African jungle" (Garrett, 1962:984).

This paper describes a new geometric method for illustrating and quantifying biological shape difference. The technique is discussed in some detail, and is illustrated by applying it to the problem of characterizing Neanderthal cranial shape. The method of thin-plate splines uses a mathematical model based on the bending of a hypothetical steel plate in order 1) objectively to generate a D'Arcy Thompson-style deformed grid that illustrates the shape contrast between two forms, and 2) to quantify the shape difference by breaking it down into a series of components based on scale.Results confirm the presence of some features traditionally attributed to Neanderthals, but some "classic'' Neanderthal features do not in fact characterize the Neanderthal sample. Traits may have been misidentified because of failure to take into account differences in absolute size, use of a misleading frame of reference, and interpretation of one aspect of a large-scale change as a localized feature. In particular, the important Neanderthal "specialization" midfacial prognathism, defined as forward displacement of the nasal region and the tooth row relative to more lateral facial structures, does not appear to be a typical Neanderthal trait. The uniqueness of Neanderthals appears to have been exaggerated, and may be related to Boule's peculiar, flawed reconstruction of the skull of La Chapelle-aux-Saints. The method of thinplate splines is a powerful technique, capable ofproviding a new and insightful perspective on morphological problems in physical anthropology. Physical anthropologists have long been concerned with measurement of biological shape and the quantification of shape differences. Over time, more and more effective methods for this task have become available. Most recently, the field of geometric morphometrics has offered a variety of new techniques, which yield much richer information on shape difference than was possible in the past. One of these techniques, the method of thin-plate splines (Bookstein, 1989, 19911, seems particularly well suited to the kinds of problems commonly approached by physical anthropologists. The thin-plate spline generates useful illustrations of shape difference, and allows one rigorously to address the issue of geometric scale: to ascertain which shape differences are large-scale, involving coordinated changes across broad areas of the form, and which are localized to more limited regions. This article outlines the technique in some detail, using a well known paleoanthropological problem as an example.The thin-plate spline is one of a series of new geometric techniques for assessing shape difference. Geometric morphometrics goes beyond traditional shape analysis by gaining more information from the landmarks under study. Not only information on chords and angles is included, but information regarding the relative positions of the landmarks is retained as well. Reviewing 0 1996 WILEY-LISS, INC

This paper describes a new geometric method for illustrating and quantifying biological shape difference. The technique is discussed in some detail, and is illustrated by applying it to the problem of characterizing Neanderthal cranial shape. The method of thin-plate splines uses a mathematical model based on the bending of a hypothetical steel plate in order 1) objectively to generate a D'Arcy Thompson-style deformed grid that illustrates the shape contrast between two forms, and 2) to quantify the shape difference by breaking it down into a series of components based on scale.

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