Male facial cues to physical strength in Europe: Medium-strength preference and higher aggressiveness attribution to the weakest.

OBJECTIVES: The capacity to assess male physical strength from facial cues may be adaptive given health and fitness-related associations with muscular strength. Our study complements recent research on strength-related face perceptions of male Maasai by applying the protocol to male European faces and assessors. METHODS: Five distinct facial morphs calibrated for handgrip strength (HGS) were manufactured with geometric morphometrics performing regressions of the Procrustes shape coordinates on HGS in a sample of 26 European men (18-32 years). Young adult men and women (n = 445) rated these morphs on physical strength, attractiveness, and aggressiveness. RESULTS: Facial morphs calibrated to lower HGS were rated as less strong, less attractive, and more aggressive than those calibrated to higher HGS. Medium levels of HGS were associated with the highest attractiveness ratings. CONCLUSIONS: The rating patterns of physical strength, attractiveness, and aggressiveness for European male facial morphs exhibit similarity to previous ratings of Maasai male faces. Therefore, the current findings corroborate the suggestion of a common mechanism for social attributions based on facial cues to physical strength, modulated by local ecology and societal context.

Perception of strength, attractiveness and aggressiveness of Maasai male faces calibrated to handgrip strength: Evidence from a European sample.

OBJECTIVES: Previous research showed that male and female members of the Maasai from Northern Tanzania judge images of facial morphs calibrated to greater handgrip strength (HGS) higher on strength and attractiveness, but lower on aggressiveness than those calibrated to lower HGS. The accurate assessment of male physical strength from facial information may be adaptive as suggested by the evidence on health and fitness-related benefits linked to high muscular strength. METHODS: This study extends previous work by obtaining European female (n = 220) and male (n = 51) assessments of HGS-calibrated Maasai male faces. Participants rated five facial morphs for strength, attractiveness, and aggressiveness on computer screens. RESULTS: Perceived physical strength increased with morphs calibrated to higher HGS. The lowest and highest HGS morphs were judged lower in attractiveness than the others, and rated aggressiveness decreased in morphs calibrated to higher HGS. CONCLUSIONS: Given the high similarity between the current study findings and those previously reported from intra-population assessments of Maasai faces calibrated to HGS, we suggest that strength and aggressiveness perceptions of facial features associated with male physical strength may be universal. Attractiveness assessments of strength-related information in the faces of (very) strong men were less consistent across populations, possibly attributable to cultural and ecological contexts.

Handgrip strength and 2D : 4D in women: homogeneous samples challenge the (apparent) gender paradox.

The length ratio between the second and the fourth digit (2D : 4D) is a retrospective, non-invasive biomarker for prenatal androgen exposure. It was found to be negatively correlated with handgrip strength (HGS) in men, but the evidence for women is mixed. Such studies in women call for increased detection sensitivity. The present study was designed to reduce potential confounding factors, especially age and ethnicity variation. We measured the digit ratios and HGS of 125 healthy women between 19 and 31 years of age from a remote region in Austria. 2D : 4D of both hands was significantly and negatively correlated with HGS (n = 125, right hand: r = -0.255, p = 0.002, left hand: r = -0.206, p = 0.011). Size, direction and significance of correlation coefficients remained stable when statistically controlling for age, body weight, body height, body mass index or hours of exercise per week. This yields theory-consistent evidence that HGS and 2D : 4D are clearly associated in women-when sufficiently reducing genetic variation (confounding 2D : 4D), the ontogenetic environment and age ranges (confounding HGS) in the study population. This finding implies similar organizing effects of prenatal androgens as in men, pointing to a more parsimonious developmental mechanism and a new look into its proximate and ultimate causes.

Correlation of the human pubic symphysis surface with age-at-death: a novel quantitative method based on a bandpass filter.

Age-at-death estimation from skeletal remains typically utilizes the roughness of pubic symphysis articular surfaces. This study presents a new quantitative method adapting a tool from geometric morphometrics, bandpass filtering of partial warp bending energy to extract only age-related changes of the surfaces. The study sample consisted of 440 surface-scanned symphyseal pubic bones from men between 14 and 82 years of age, which were landmarked with 102 fixed and surface semilandmarks. From the original sample, 371 specimens within Procrustes distance of 0.05 of the side-specific average were selected. For this subsample, age was correlated with total bending energy (calculated as summed squared partial warps amplitudes) for a wide range of plausible bandpass filters. For our subsample's 188 right-side surfaces, the correlation between age and bandpass filtered versions of bending energy peaks relatively sharply at r = -0.648 for ages up through 49 years against the first seven partial warp amplitudes only. The finding for left symphyses is similar. The results demonstrate that below the age 50, the symphyseal surface form changes most systematically related to age may be best detected by a lowpass-filtered version of bending energy: signals at the largest geometric scales of roughness rather than its full spectrum. Combining this method with information from other skeletal features could further improve age-at-death estimation based on the symphyseal pubic surface.

Facial aging trajectories: A common shape pattern in male and female faces is disrupted after menopause.

OBJECTIVES: Despite variation in lifestyle and environment, first signs of human facial aging show between the ages of 20-30 years. It is a cumulative process of changes in the skin, soft tissue, and skeleton of the face. As quantifications of facial aging in living humans are still scarce, we set out to study age-related changes in three-dimensional facial shape using geometric morphometrics. MATERIALS AND METHODS: We collected surface scans of 88 human faces (aged 26-90 years) from the coastal town Split (Croatia) and neighboring islands. Based on a geometric morphometric analysis of 585 measurement points (landmarks and semilandmarks), we modeled sex-specific trajectories of average facial aging. RESULTS: Age-related facial shape change was similar in both sexes until around age 50, at which time the female aging trajectory turned sharply. The overall magnitude of facial shape change (aging rate) was higher in women than men, especially in early postmenopause. Aging was generally associated with a flatter face, sagged soft tissue ("broken" jawline), deeper nasolabial folds, smaller visible areas of the eyes, thinner lips, and longer nose and ears. In postmenopausal women, facial aging was best predicted by the years since last menstruation and mainly attributable to bone resorption in the mandible. DISCUSSION: With high spatial and temporal resolution, we were able to extract a shared facial aging pattern in women and men, and its divergence after menopause. This fully quantitative three-dimensional analysis of human facial aging may not only find applications in forensic and ancient human facial reconstructions, but shall include lifestyle and endocrinological measures, and also reach out to studies of social perception.

Galectin-9 binds to O-glycans on protein disulfide isomerase.

Changes in the T cell surface redox environment regulate critical cell functions, such as cell migration, viral entry and cytokine production. Cell surface protein disulfide isomerase (PDI) contributes to the regulation of T cell surface redox status. Cell surface PDI can be released into the extracellular milieu or can be internalized by T cells. We have found that galectin-9, a soluble lectin expressed by T cells, endothelial cells and dendritic cells, binds to and retains PDI on the cell surface. While endogenous galectin-9 is not required for basal cell surface PDI expression, exogenous galectin-9 mediated retention of cell surface PDI shifted the disulfide/thiol equilibrium on the T cell surface. O-glycans on PDI are required for galectin-9 binding, and PDI recognition appears to be specific for galectin-9, as galectin-1 and galectin-3 do not bind PDI. Galectin-9 is widely expressed by immune and endothelial cells in inflamed tissues, suggesting that T cells would be exposed to abundant galectin-9, in cis and in trans, in infectious or autoimmune conditions.

Signatures of positive selection in the cis-regulatory sequences of the human oxytocin receptor (OXTR) and arginine vasopressin receptor 1a (AVPR1A) genes.

BACKGROUND: The evolutionary highly conserved neurohypophyseal hormones oxytocin and arginine vasopressin play key roles in regulating social cognition and behaviours. The effects of these two peptides are meditated by their specific receptors, which are encoded by the oxytocin receptor (OXTR) and arginine vasopressin receptor 1a genes (AVPR1A), respectively. In several species, polymorphisms in these genes have been linked to various behavioural traits. Little, however, is known about whether positive selection acts on sequence variants in genes influencing variation in human behaviours. RESULTS: We identified, in both neuroreceptor genes, signatures of balancing selection in the cis-regulative acting sequences such as transcription factor binding and enhancer sequences, as well as in a transcriptional repressor sequence motif. Additionally, in the intron 3 of the OXTR gene, the SNP rs59190448 appears to be under positive directional selection. For rs59190448, only one phenotypical association is known so far, but it is in high LD' (>0.8) with loci of known association; i.e., variants associated with key pro-social behaviours and mental disorders in humans. CONCLUSIONS: Only for one SNP on the OXTR gene (rs59190448) was a sign of positive directional selection detected with all three methods of selection detection. For rs59190448, however, only one phenotypical association is known, but rs59190448 is in high LD' (>0.8), with variants associated with important pro-social behaviours and mental disorders in humans. We also detected various signatures of balancing selection on both neuroreceptor genes.

Early developmental masculinization among boys: More prenatal testosterone action (assessed via 2D:4D) renders their faces perceived as masculine but not pretty or cute.

The 'organizational-activational hypothesis' posits that the fetal environment has a lasting impact on offspring physical, cognitive, and behavioral phenotype. An established biomarker for human prenatal testosterone exposure is the second-to-fourth digit ratio (2D:4D). While related facial characteristics and their social perceptions have been investigated in young adults, studies focusing on younger or older age groups are scarce. Standardized facial photographs of 17 Austrian boys aged 4 to 11 years were each rated by 162 adults in Austria (78 female, 84 male) for masculinity, dominance, physical strength, maturity, independence, cuteness, and prettiness. Following high interrater agreement (Cronbach's alphas >0.96), average ratings per face were subjected to a principal component analysis. The first principal component (52 % var. expl.) correlated positively with the boys' age (r = 0.685), whereas the second principal component (37 % var. expl.) reflected organizational effects of prenatal androgen exposure (i.e. androgenization), as shown by a negative correlation with the boys' 2D:4D (r = -0.487). Geometric morphometrics was employed to extract the facial shapes corresponding to these two principal components. Overall, adults consistently attributed masculinity in line with prenatal testosterone exposure, whereby masculinity was assessed as neither pretty nor cute. In contrast to findings within adults, boys' face ratings of dominance and physical strength did not correspond with their masculinity assessments, but rather with the social attributions reflecting age-related developmental progress (maturity and independence). This adds an ontogenetic layer of complexity. Prenatal testosterone exposure influences the development of boys' facial features, which in turn even shape social stereotypes in adults.

Body fat and facial shape are correlated in female adolescents.

OBJECTIVES: Relative body weight is not only an important indicator for health and reproductive condition, but also subject to stereotypes and stigmatization. It can be reliably assessed from adult faces alone, yet the facial correlates, especially in adolescents, remain largely unidentified. This study was designed to determine the facial features of adolescent girls that change with body fat proportion using a modern, comprehensive technique for shape analysis. METHODS: Standardized frontal facial photographs of 22 Caucasian female adolescents (mean age 15.8 ± 2.7 years) were taken, and body height, body weight, and body fat proportion measured. Seventy-two somatometric measurement points were digitized on each photograph and their Cartesian coordinates regressed onto body fat proportion. Geometric morphometrics also enabled visualizing the statistical results as shapes. RESULTS: Body fat proportion explained 8.7% of the facial shape variation (10,000 permutations, P = 0.047). Girls with high body fat had a relatively rounder and larger lower face, relatively smaller eyes, and a shorter and wider nose, fuller lips and downturned corners of the mouth. Low body fat was associated with a more angular lower face and a pointier chin, relatively larger eyes and a longer nose. The lips were wider and thinner, the corners of the mouth upturned. CONCLUSION: Body fat proportion is a substantial factor in facial shape variation of female adolescents. The potential influence of the corresponding facial features on social perception is discussed. Prospects for future research including novel possibilities for stimuli design (GM morphs) are highlighted.

Distinct effects of leukocyte and cardiac phosphoinositide 3-kinase γ activity in pressure overload-induced cardiac failure.

BACKGROUND: Signaling from phosphoinositide 3-kinase γ (PI3Kγ) is crucial for leukocyte recruitment and inflammation but also contributes to cardiac maladaptive remodeling. To better understand the translational potential of these findings, this study investigates the role of PI3Kγ activity in pressure overload-induced heart failure, addressing the distinct contributions of bone marrow-derived and cardiac cells. METHODS AND RESULTS: After transverse aortic constriction, mice knock-in for a catalytically inactive PI3Kγ (PI3Kγ KD) showed reduced fibrosis and normalized cardiac function up to 16 weeks. Accordingly, treatment with a selective PI3Kγ inhibitor prevented transverse aortic constriction-induced fibrosis. To define the cell types involved in this protection, bone marrow chimeras, lacking kinase activity in the immune system or the heart, were studied after transverse aortic constriction. Bone marrow-derived cells from PI3Kγ KD mice were not recruited to wild-type hearts, thus preventing fibrosis and preserving diastolic function. After prolonged pressure overload, chimeras with PI3Kγ KD bone marrow-derived cells showed slower development of left ventricular dilation and higher fractional shortening than controls. Conversely, in the presence of a wild-type immune system, KD hearts displayed bone marrow-derived cell infiltration and fibrosis at early stages but reduced left ventricular dilation and preserved contractile function at later time points. CONCLUSIONS: Together, these data demonstrate that, in response to transverse aortic constriction, PI3Kγ contributes to maladaptive remodeling at multiple levels by modulating both cardiac and immune cell functions.

Second-to-fourth digit ratio and facial shape in boys: the lower the digit ratio, the more robust the face.

During human ontogeny, testosterone has powerful organizational and activational effects on the male organism. This has led to the hypothesis that the prenatal environment (as studied through the second-to-fourth digit ratio, 2D : 4D) is not only associated with robust adult male faces that are perceived as dominant and masculine, but also that there is an activational step during puberty. To test the latter, we collected digit ratios and frontal photographs of right-handed Caucasian boys (aged 4-11 years) along with age, body height and body weight. Using geometric morphometrics, we show a significant relationship between facial shape and 2D : 4D before the onset of puberty (explaining 14.5% of shape variation; p = 0.014 after 10 000 permutations, n = 17). Regression analyses depict the same shape patterns as in adults, namely that the lower the 2D : 4D, the smaller and shorter the forehead, the thicker the eyebrows, the wider and shorter the nose, and the larger the lower face. Our findings add to previous evidence that certain adult male facial characteristics that elicit attributions of masculinity and dominance are determined very early in ontogeny. This has implications for future studies in various fields ranging from social perception to life-history strategies.

A new concept for glycosyltransferase inhibitors: nonionic mimics of the nucleotide donor of the human blood group B galactosyltransferase.

Glycosyltransferases play an important role in the formation of oligosaccharides and glycoconjugates. To find suitable and selective inhibitors for this class of enzymes is still challenging. Here, we describe a novel concept that allows the design of inhibitors based on the structure of the donor substrate binding pocket. As a first step we describe the design, synthesis and analysis of inhibitors of the human blood group B galactosyltransferase (GTB). This enzyme served as a model system to study the concept, which can be used for easy access of glycosyltransferase inhibitors in general. In silico docking of bicyclic heteroaromatic ligands to GTB and experimental verification of binding affinities by saturation transfer difference NMR (STD NMR) spectroscopy gave 9-N-pentityl uric acid derivatives as non-ionic mimics of UDP. Two derivatives were synthesized and showed inhibitory activity for GTB as determined by competitive STD NMR experiments and by a radiolabeled enzyme assay.

Thirty years of geometric morphometrics: Achievements, challenges, and the ongoing quest for biological meaningfulness.

The foundations of geometric morphometrics were worked out about 30 years ago and have continually been refined and extended. What has remained as a central thrust and source of debate in the morphometrics community is the shared goal of meaningful biological inference through a tight connection between biological theory, measurement, multivariate biostatistics, and geometry. Here we review the building blocks of modern geometric morphometrics: the representation of organismal geometry by landmarks and semilandmarks, the computation of shape or form variables via superimposition, the visualization of statistical results as actual shapes or forms, the decomposition of shape variation into symmetric and asymmetric components and into different spatial scales, the interpretation of various geometries in shape or form space, and models of the association between shape or form and other variables, such as environmental, genetic, or behavioral data. We focus on recent developments and current methodological challenges, especially those arising from the increasing number of landmarks and semilandmarks, and emphasize the importance of thorough exploratory multivariate analyses rather than single scalar summary statistics. We outline promising directions for further research and for the evaluation of new developments, such as "landmark-free" approaches. To illustrate these methods, we analyze three-dimensional human face shape based on data from the Avon Longitudinal Study of Parents and Children (ALSPAC).

Geometric morphometrics of male facial shape in relation to physical strength and perceived attractiveness, dominance, and masculinity.

OBJECTIVES: Evolutionary psychologists claim that women have adaptive preferences for specific male physical traits. Physical strength may be one of those traits, because recent research suggests that women rate faces of physically strong men as more masculine, dominant, and attractive. Yet, previous research has been limited in its ability to statistically map specific male facial shapes and features to corresponding physical measures (e.g., strength) and ratings (e.g., attractiveness). METHODS: The association of handgrip strength (together with measures of shoulder width, body height, and body fat) and women's ratings of male faces (concerning dominance, masculinity, and attractiveness) were studied in a sample of 26 Caucasian men (aged 18-32 years). Geometric morphometrics was used to statistically assess the covariation of male facial shape with these measures. Statistical results were visualized with thin-plate spline deformation grids along with image unwarping and image averaging. RESULTS: Handgrip strength together with shoulder width, body fat, dominance, and masculinity loaded positively on the first dimension of covariation with facial shape (explaining 72.6%, P < 0.05). These measures were related to rounder faces with wider eyebrows and a prominent jaw outline while highly attractive and taller men had longer, narrower jaws and wider/fuller lips. CONCLUSIONS: Male physical strength was more strongly associated with changes in face shape that relate to perceived masculinity and dominance than to attractiveness. Our study adds to the growing evidence that attractiveness and dominance/masculinity may reflect different aspects of male mate quality.

Laying eyes on headlights: eye movements suggest facial features in cars.

Humans' proneness to see faces even in inanimate structures such as cars has long been noticed, yet empirical evidence is scarce. To examine this tendency of anthropomorphism, participants were asked to compare specific features (such as the eyes) of a face and a car front presented next to each other. Eye movement patterns indicated on which visual information participants relied to solve the task and clearly revealed the perception of facial features in cars, such as headlights as eyes or grille as nose. Most importantly, a predominance of headlights was found in attracting and guiding people's gaze irrespective of the feature they were asked to compare--equivalent to the role of the eyes during face perception. This response to abstract configurations is interpreted as an adaptive bias of the respective inherent mechanism for face perception and is evolutionarily reasonable with regard to a "better safe than sorry" strategy.

Social Perception of Faces: Brain Imaging and Subjective Ratings.

The aim of this study was to investigate how a female face is perceived in terms of its attractiveness, dominance, health, femininity-masculinity, and maturity in direct relation to the body fat percentage (BFP) conveyed by the face. To compare how young adults (ages 18 to 35) respond to different levels of body fat percentage both subjectively and objectively we collected survey ratings and electroencephalography (EEG) data across five different levels of BFP from 40 participants. We adapted the experimental design from a prior behavioral study and used calibrated and morphed female face images of five different BFP levels. The results of the survey are in consensus with the previous study and assessed to be a successful replication. From the EEG data, event-related potentials (ERPs) were extracted from one electrode location (right occipitotemporal brain region) known to be particularly sensitive to face-stimuli. We found statistically significant differences in the amplitudes of the P200 component (194 ms post stimulus onset) between the thickest face and all four other BFP conditions, and in the amplitudes of the N300 component (274 ms post stimulus onset) between the average face and three other BFP conditions. As expected, there were no significant differences among the N170 amplitudes of all five BFP conditions since this ERP component simply reflects the processing of faces in general. From these results, we can infer that holistic face encoding characterized by the N170 component in the right occipitotemporal area is followed by serial evaluative processes, whose categorical and qualitative matrix and spatiotemporal dynamics should be further explored in future studies, especially in relation to the social constructs that were focused on in this study.

Cigarette smoke exposure promotes arterial thrombosis and vessel remodeling after vascular injury in apolipoprotein E-deficient mice.

BACKGROUND: Cigarette smoking is a major risk factor for the development of cardiovascular disease. However, in terms of the vessel wall, the underlying pathomechanisms of cigarette smoking are incompletely understood, partly due to a lack of adequate in vivo models. METHODS: Apolipoprotein E-deficient mice were exposed to filtered air (sham) or to cigarette mainstream smoke at a total particulate matter (TPM) concentration of 600 microg/l for 1, 2, 3, or 4 h, for 5 days/week. After exposure for 10 +/- 1 weeks, arterial thrombosis and neointima formation at the carotid artery were induced using 10% ferric chloride. RESULTS: Mice exposed to mainstream smoke exhibited shortened time to thrombotic occlusion (p < 0.01) and lower vascular patency rates (p < 0.001). Morphometric and immunohistochemical analysis of neointimal lesions demonstrated that mainstream smoke exposure increased the amount of alpha-actin-positive smooth muscle cells (p < 0.05) and dose-dependently increased the intima-to-media ratio (p < 0.05). Additional analysis of smooth muscle cells in vitro suggested that 10 microg TPM/ml increased cell proliferation without affecting viability or apoptosis, whereas higher concentrations (100 and 500 microg TPM/ml) appeared to be cytotoxic. CONCLUSIONS: Taken together, these findings suggest that cigarette smoking promotes arterial thrombosis and modulates the size and composition of neointimal lesions after arterial injury in apolipoprotein E-deficient mice.

Leptin receptor is elevated in carotid plaques from neurologically symptomatic patients and positively correlated with augmented macrophage density.

BACKGROUND: Carotid artery lesions from symptomatic patients are characterized by inflammation and neovascularization. The adipokine leptin promotes angiogenesis and activates inflammatory cells, and the leptin receptor (ob gene-encoded receptor), ObR, is expressed in advanced atherosclerotic lesions. The present study quantitatively analyzed ObR messenger RNA (mRNA) expression and immunoreactivity in carotid artery plaques from symptomatic and asymptomatic persons. Plaque angiogenesis, gene expression of vascular endothelial growth factor (VEGF), and macrophage density were also analyzed. METHODS: Carotid endarterectomy specimens were collected from 26 patients undergoing surgery for hemispheric cerebrovascular symptoms (n = 13) or progressive asymptomatic internal carotid stenosis (n = 13). A representative sample, including part of the most active site, was collected from each lesion and evaluated by real-time polymerase chain reaction analysis for ObR(long) and ObR(common) isoforms, VEGF(165), and macrophage adhesion molecule-1 (Mac-1) mRNA, and by immunohistochemistry for ObR, von Willebrand factor (vWF), and CD68 antigen expression. RESULTS: All plaques exhibited advanced atherosclerosis (American Heart Association class IV through VI). Transcript levels were preferentially elevated in symptomatic plaques for ObR(long) (P = .0006) and ObR(common) (P = .033), with a simultaneous upregulation of VEGF(165) (P = .001) and Mac-1 mRNA expression (P = .003). Immunohistochemical analysis confirmed a significant increase of ObR antigen levels (P = .011) and CD68-positive inflammatory cells (P = .049) in symptomatic plaques, whereas neovascularization, evident in all plaques, was similar in both groups (P = .7). CONCLUSION: The ObR(long) and ObR(common) genes are upregulated and their protein preferentially synthesized in clinically symptomatic carotid plaques. Moreover, ObR expression is positively correlated with augmentation of gene transcripts related to macrophage density and neovascularization. These data suggest that ObR(long) and ObR(common) may be linked with histologic features of carotid plaque instability, which are associated with cerebral ischemic symptoms.

Face to Face : The Perception of Automotive Designs.

Over evolutionary time, humans have developed a selective sensitivity to features in the human face that convey information on sex, age, emotions, and intentions. This ability might not only be applied to our conspecifics nowadays, but also to other living objects (i.e., animals) and even to artificial structures, such as cars. To investigate this possibility, we asked people to report the characteristics, emotions, personality traits, and attitudes they attribute to car fronts, and we used geometric morphometrics (GM) and multivariate statistical methods to determine and visualize the corresponding shape information. Automotive features and proportions are found to covary with trait perception in a manner similar to that found with human faces. Emerging analogies are discussed. This study should have implications for both our understanding of our prehistoric psyche and its interrelation with the modern world.

Secular trends in the European male facial skull from the Migration Period to the present: a cephalometric study.

Secular trends in the facial skull over three Central European samples spanning more than 13 centuries were examined. Data were 43 conventional cephalometric landmark points for samples dating from 680 to 830 AD (29 male Avars), from the mid-19th century (49 adult Hapsburg Monarchy males), and from the 20th century (54 living Austrian young adult males). Analyses by standard methods of geometric morphometrics demonstrated shape differences by data and by size, with a strong interaction of these with sample, in that group mean differences were different for small and large individuals (allometry is different from period to period). The oldest sample, from the Migration Period, exhibited allometric features that may possibly be Turkic. There are implications for the orthodontist interested in growth trends or growth predictions in ethnically mixed patient samples.