PubMed · 16628984
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Matthew J Bueche. 2006. Measuring angles.. https://doi.org/10.3928/01477447-20060401-09
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The phenotypic variance (V(P)) may be divided into the genetic variance (V(G)), the general environmental variance (V(Eg)), and the special environmental variance (V(Es)). The latter is estimated through repeatability calculation (b). This value is considered the upper limit of heritability and represents maximum genetic variance proportion (V(Gm) = V(G) + V(Eg)) in relation to V(P) (b = (V(G) + V(Eg))/V(P)). This process allows an improved determination of biological relationships among groups from estimators maximizing the genetic information of quantitative characters. Two hundred and thirty-seven individuals inhabiting the northern coast of Chile for 4,000 years were taken as a sample. Measurement was made of six metric characters at both sides of the cranium. Special environmental values (es) were obtained by regression. The difference between these values and the phenotypic values (p) consists in the genetic values plus the general environmental values (g + eg). A mean b value of 0.83 indicated that V(Es) represents 17% of V(P). The results showed: 1) high stability of the maximum genetic variance in time and space, 2) high correlation between the biological relationships model, the phenotypic model, and the maximum genetic model, and 3) random distribution of the nongenetic variation, as expected from the quantitative genetics theory. These results support the use of phenotypic data for the interpretation of the evolution history of prehistoric populations.
The present study proposes a simple and reproducible method to classify the morphology of the suprascapular notch (SSN), on the basis of specific geometrical parameters that clearly distinguish one type from another. Four hundred twenty-three dried scapulas from the Department of Anatomy in the University of Cologne, Germany, were examined. Five types of SSN were observed: type I, without a discrete notch, 35 (8.3%); type II, a notch that was longest in its transverse diameter, 177 (41.85%); type III, a notch that was longest in its vertical diameter, 177 (41.85%); type IV, a bony foramen, 31 (7.3%); type V, a notch and a bony foramen, 3 (0.7%). For the vertical diameter, we took the maximal diameter of the notch perpendicular to the imaginary line that joins the two superior corners of the notch. For the transverse diameter, we took the diameter perpendicular to the midpoint of the vertical diameter. This classification based on the vertical and the transverse diameters of the SSN suggested a clear distinction of the notch types. This simple classification included all the anatomical variations of the SSN. Using this method, the clinician will be able to define easily and quickly the notch type on a plain radiograph, and perhaps be able to correlate suprascapular nerve entrapment with a specific type of SSN.
BACKGROUND: Although morphologic abnormalities are common among HIV-infected persons receiving highly active antiretroviral therapy (HAART), longitudinal comparative body shape changes among HAART-treated HIV-infected men versus HIV-seronegative men of similar age remain unclear. METHODS: Since September 1999, men enrolled in the Multicenter AIDS Cohort Study underwent body mass index (BMI) and circumference measurements of the waist, hip, thigh, and arm at each semiannual visit. Changes in these measurements that occurred between 1999 and 2003 among HIV-infected men were compared with measurements of HIV-seronegative men using linear mixed effects regression models. The HIV-infected men were further stratified by treatment group (no antiretroviral therapy [ART], monotherapy or combination [mono/combo] ART, or HAART). Analyses were adjusted for age, nadir CD4 cell count, and BMI (for circumference measurements). RESULTS: Over the 4-year observation period, mean BMI increased significantly among the 392 HIV-seronegative men (0.12 kg/m/y; P < 0.001) but did not change in the 3 HIV-infected groups (combined n = 661). Mean waist and hip circumferences increased significantly in all groups. Hip circumferences increased more slowly in the HIV-positive HAART-treated group (n = 488) than in the HIV-seronegative group (0.18 vs. 0.49 cm/y; P < 0.001), however, yielding a more rapid increase in the waist/hip ratio in the HIV-positive, HAART-treated group over time (0.005 per year; P < 0.001). CONCLUSIONS: The increased rate of change in waist/hip ratio in HIV-infected men receiving HAART compared with HIV-seronegative men is attributable to slower increases in hip circumference rather than an increased rate of change in waist circumference. These findings underscore the importance of body fat composition changes in the peripheral compartment relative to the central compartment among HIV-infected men receiving HAART.