Direct Discriminant Function Analysis Research Articles

Utility of the metatarsal diaphyseal nutrient foramen in estimating sex in the South African Africans population

IntroductionSex estimation is challenging in cases where dismembered or non-intact skeletal remains are recovered. Therefore, the development of sex estimation standards using various bones that present with high recovery rates during forensic investigations, like the metatarsal bones, is needed. The usefulness of the dimensions around the metatarsal diaphyseal nutrient foramen in sex estimation has not been assessed in South African Africans (SAA), constituting the majority of the country's population. Materials and methodsFive measurements around the nutrient foramen were taken from 995 metatarsal bones (first to fifth) from 200 individual skeletons (100 males, 100 females). Measurements subjected to direct and stepwise discriminant function (DFA) and logistic regression (LRA) analyses included the total length, distance from proximal end to nutrient foramen, circumference, and mediolateral and dorsoplantar diameters at the level of the nutrient foramen. ResultsThe original classification accuracies for multivariable functions of the stepwise and direct DFA ranged from 75.1 to 80 % and 76–79.5 % respectively. The original classification accuracies for multivariable functions of the stepwise and direct LRA ranged from 76.3% to 79.5 % and 75%–80.5 % respectively. The cross-validation classifications showed a drop of 0–2% for DFA and 0.2–1.9 % for LRA. Overall breadth measurements showed better classification accuracies than length measurements and females were classified with higher accuracy rates than males. ConclusionThe dimensions around the nutrient foramen of the metatarsal bones show sexual dimorphism in the SAA. The generated DFA and LRA functions produced high average classification accuracies which can be appropriate for use in sex estimation in forensic settings, especially when an isolated foot is recovered.

Evaluating the patella bone for sex estimation in Northwest Indian subjects: A radiological study

ObjectivesIn forensic identification, pelvis, post cranial bones especially long bones and skull are considered best for sex estimation. But there are circumstances where these bones cannot be recovered for establishing the correct biological profile of unknown human skeletal remains. In those cases, other skeletal bones should be investigated for sex estimation. The goal of the present study was to validate whether the patellar bone measurements through CT scan can be used for the sex estimation in Northwest Indian subjects. Materials and methodsThis study comprises of 344 subjects (179 males and 165 females) between the age group of 18- 80 years. Eight variables of patella were selected in the study for sex estimation using CT scan images of patella. ResultsAll the variables were statistically significant with p-value< 0.05 for indicating the sex. Univariate and multivariate discriminant function analysis (direct and stepwise method) were applied for sex estimation. The overall accuracy rate of classifying sex was 88.4% for multivariate stepwise discriminant function analysis and 87.8% for multivariate direct discriminant function analysis. Total perimeter of patella (TPP) was found to be the best variable for sex estimation with overall accuracy rate of 84.9%. ConclusionThe present study emphasized on the most dimorphic variables of patella in Northwest Indian subjects. New variables of patella namely Patellar Femoral Distance (PFD), Patellar Apex Angle (PAA), Frontal Surface Area of patella (FSA) and Total Perimeter of Patella (TPP) were added in the study of Indian subjects. This brought an overall accuracy rate of classification above 85%. The study confirmed that patellar bone's linear and angular measurements can be used for forensic identification casework.

Cranio-facial bones evaluation based on clinical CT data for sex determination in Northwest Indian population

The skull and pelvis have been the first choice of bones for determination of unknown human remains. The goal of the present study was to derive discriminant function equations by using clinical CT scan data of cranio-facial bones for sex determination in Northwest Indian population. This study was conducted at Department of Radiology, by collecting the retrospective data of CT scan of 217 samples. In the data, 106 were males and 111 were females in the age group between 20 and 80 years. The total number of parameters under investigation were 10. All the selected variables were sexually dimorphic and showed significant values. 91.7% of original grouped cases were correctly classified to their sex category. The TEM, rTEM and R were under the acceptable limits. The univariate, multivariate and stepwise discriminant function analysis recorded an accuracy of 88.9%, 91.7% and 93.6% respectively. Multivariate direct discriminant function analysis stepwise method yielded the highest level of accuracy in differentiating males and females. All the variables reflected statistically significant difference between males and females (p less than 0.001). The best single parameter with highest level of sexual dimorphic trait was length of cranial base. This study aims to provide sex assessment using clinical data of CT scan in Northwest Indian population by incorporating the BIOFB cranio-facial parameter. The morphometric measurements taken on CT scan images can be utilized by forensic experts in identification process.

Machine learning and discriminant function analysis in the formulation of generic models for sex prediction using patella measurements

Sex prediction from bone measurements that display sexual dimorphism is one of the most important aspects of forensic anthropology. Some bones like the skull and pelvis display distinct morphological traits that are based on shape. These morphological traits which are sexually dimorphic across different population groups have been shown to provide an acceptably high degree of accuracy in the prediction of sex. A sample of 100 patella of Mixed Ancestry South Africans (MASA) was collected from the Dart collection. Six parameters: maximum height (maxh), maximum breadth (maxw), maximum thickness (maxt), the height of articular facet (haf), lateral articular facet breadth (lafb), and medial articular facet breath (mafb) were used in this study. Stepwise and direct discriminant function analyses were performed for measurements that exhibited significant differences between male and female mean measurements, and the “leave-one-out” approach was used for validation. Moreover, we have used eight classical machine learning techniques along with feature ranking techniques to identify the best feature combinations for sex prediction. A stacking machine learning technique was trained and validated to classify the sex of the subject. Here, we have used the top performing three ML classifiers as base learners and the predictions of these models were used as inputs to different machine learning classifiers as meta learners to make the final decision. The measurements of the patella of South Africans are sexually dimorphic and this observation is consistent with previous studies on the patella of different countries. The range of average accuracies obtained for pooled multivariate discriminant function equations is 81.9–84.2%, while the stacking ML technique provides 90.8% accuracy which compares well with those presented for previous studies in other parts of the world. In conclusion, the models proposed in this study from measurements of the patella of different population groups in South Africa are useful resent with reasonably high average accuracies.

Accuracies of discriminant function equations for sex estimation using long bones of upper extremities.

One of the scopes of practice of forensic anthropologists is the estimation of sex from skeletal remains. As a result, population-specific discriminant function equations have been developed from measurements of various bones of the human skeletons. Steyn, Patriquin (Forensic Sci Int 191 (1-3):113, 2009) noted that the lack of skeletal collections and data from most parts of the world has made this process impractical. Previous attempts to develop global discriminant function equations from measurements of the pelvis showed that population-specific equations are not necessary as equations derived from other populations yielded high sex estimation scores when applied to a different population. However, information on the suitability and applicability of generalised equations in sex estimation using long bones is still scarce. It is, therefore, the aim of this study to assess the accuracies of population-specific discriminant function equations derived from measurements of long bones of the upper limb of South African population groups. Data analysed in the current study were obtained from Mokoena, Billings, Bidmos, Mazengenya (Forensic Sci Int 278:404, 2017) and Mokoena, Billings, Gibbon, Bidmos, Mazengenya (Science & Justice 6(59):660-666, 2019) in which a total sample of 988 bones (humeri, radii, and ulnae) of South Africans of African descent (SAAD), South Africans of European descent (SAED) and Mixed Ancestry South Africans (MASA) were measured. Stepwise and direct discriminant function analyses were performed on the pooled data. Each function was used to estimate the sex of cases in each population group separately and average accuracies calculated. Thereafter, population-specific discriminant function equations were formulated for each population group and then applied to other population groups. The average accuracies of functions for pooled data ranged between 80.7 and 86.5%. The cross-validation average accuracies remained unchanged for most functions, confirming the validity of derived functions. A drop in average accuracies (0.8-5.3%) was observed when the functions were tested on a sample of SAAD while increased average accuracy was observed for the SAED and MASA (0.5-6.9%). When population-specific functions for a particular population group were applied to other groups, a wide range of a drop in average accuracies was observed (1.3 to 22.4%). This thereby confirms that population-specific equations should not be applied to other population groups. However, discriminant function equations from the pooled data of South Africans are accurate in the estimation of sex and efforts should be made towards the development and validation of such equations from as many bones of the human skeleton.

Estimation of sex from the metacarpal dimensions at the nutrient foramen in white South Africans

ABSTRACT Sex estimation is important in both forensic and archaeological cases and requires a variety of bones and measurements to obtain accurate estimates. Discriminant function analysis equations on postcranial elements are associated with population specificity, hence the need to generate equations for each population group. The current study examined the utility of the measurements around the nutrient foramen of the metacarpals for sex estimation from white South Africans. The study utilized 520 left metacarpals from 104 adult skeletons of white South Africans of known sex (53 males, 51 females) and age at death (range 21 to 65 years) obtained from the Raymond A. Dart Collection of Human Skeletons at the University of the Witwatersrand. Measurements that were subjected to stepwise and direct discriminant function analyses include total length, distance from proximal end to nutrient foramina, circumference, palmar-dorsal diameter, and mediolateral diameter at the level of the nutrient foramen. Combinations of breadth measurements of the first and second metacarpals produced high sex estimation scores ranging from 82% to 91% (stepwise discriminant function analysis) and 82–94% (direct discriminant function analysis) indicating that the dimensions around the nutrient foramen of the metacarpals are useful in sex estimation and can be used in fragmentary bones.

Sex estimation from the femur using discriminant function analysis in a Central Indian population.

Sexual dimorphism is one of the major factors responsible for apparent variations in human skeletal anatomy. Establishing the biological profile of the deceased is essential for personal identification in forensic and archaeological casework. To develop a reliable biological profile, sex allocation is an integral step required to determine age, race/ancestry and stature, given observable differences in aging and growth patterns and variations in morphological traits relating to ancestry. Sex estimation from long bones by visual examination is very difficult. However, metric observations are more objective and effective. This osteometric analysis focused on sex estimation from the femur using discriminant function analysis. Fourteen measurements were taken directly on 175 dry femora (117 males and 58 females), aged 20–60 years, from the Chhattisgarh region of Central India. Student’s t-test was applied to assess significant sex and size differences. Direct and stepwise discriminant function analyses were applied to derive discriminant function models for sex estimation. The three parameters that were selected for the discriminant function analysis included: transverse head diameter, bi-trochanteric distance and maximum shaft diameter. Males were more accurately classified than females. An overall accuracy of 80.6% was reported with direct discriminant function analysis and 76% with stepwise discriminant function analysis upon cross-validation. The transverse head diameter emerged to be the best predictor of sex. This study provides a database and standards for sex estimation from skeletal remains of an unknown nature based on discriminant function equations. This is one of the few studies conducted in India on dry bones, and we anticipate that it will guide forensic specialists in the identification of unknown skeletons from this region.

Three-dimensionally derived interlandmark distances for sex estimation in intact and fragmentary crania

The skull is the element most frequently presented to forensic anthropologists for analysis yet weathering, corpse maiming, and scavenger activity often result in damage and fragmentation. This fragmentation results in a reduction in the number of traditional calliper derived measurements that can be obtained and subjected to discriminant based analyses for sex estimation. In this investigation, we employed three-dimensional geometric morphometric methods to derive novel interlandmark distance measures across six regions of the cranium including the basicranium, basipalate, zygoma, orbits and the cranium globally to create functions to discriminate sex with high efficacy, even in the event of fragmentation. Forty-five homologous landmarks were digitised across each of 227 (114 males and 113 females) South African crania of European descent (white) sampled from the Raymond A Dart Collection of Human Skeletons, housed in the School of Anatomical Sciences, University of the Witwatersrand, South Africa. A total of 990 interlandmark distances (ILDs) were mathematically derived using Pythagorean geometry. These ILDs were then filtered by region and subjected to both direct and stepwise discriminant function analyses. Discriminant equations where derived for each region and achieved the following average cross-validated sex estimation accuracies: basicranium—74%; basipalate—80.2%; zygomatic—82.4; orbits—71.8%; nasomaxilla—83.7%; global cranium—88.2%. A large number of the ILDs used to derive the discriminant functions are novel, demonstrating the efficacy of geometric morphometric methods and illustrating the need to reassess old methods of data collection using modern methods to determine whether they best capture biological differences. The results of this study provide an invaluable contribution to forensic anthropology in South Africa as it provides an accurate, practical means of assessing sex using fragmentary material that may otherwise have been disregarded. These will undeniable aid in accurate sex estimation and ultimately, victim identification.

Sex determination from calcaneus in Gujarati population by discriminant function analysis

IntroductionSex, age and racial affinity are the three most vital determinations that must be made when dealing with skeletal remains. Success in sex determination from skeletal remains is limited as most of the bones are available in fragments. The calcaneus, the largest tarsal bone, is apt for studying sexual dimorphism as it is relatively well preserved due to its density. MethodsEleven measurements of 51 adult human calcanei (31 male and 20 female) have been taken to determine accuracy of calcaneus in sex determination and to derive sex discriminant function equations specific for Gujarati population. ResultsThe correct sex classification rate after the direct discriminant function analysis of all parameters is 94.25%. Subsequent to stepwise analysis, two parameters (dorsal articular facet length and middle breadth) have been selected as the best sex determinants with an accuracy of 94.3%. Among the dimensional groups, the breadth dimensional group has the highest accuracy. The sex discriminant function equations specific for Gujarati population have been derived. DiscussionThe accuracy rate in sex determination obtained in the present study is comparable to the accuracy rates reported by previous researchers.

Assessment of craniometric traits in South Indian dry skulls for sex determination

The skeleton plays an important role in sex determination in forensic anthropology. The skull bone is considered as the second best after the pelvic bone in sex determination due to its better retention of morphological features. Different populations have varying skeletal characteristics, making population specific analysis for sex determination essential. Hence the objective of this investigation is to obtain the accuracy of sex determination using cranial parameters of adult skulls to the highest percentage in South Indian population and to provide a baseline data for sex determination in South India. Seventy adult preserved human skulls were taken and based on the morphological traits were classified into 43 male skulls and 27 female skulls. A total of 26 craniometric parameters were studied. The data were analyzed by using the SPSS discriminant function. The analysis of stepwise, multivariate, and univariate discriminant function gave an accuracy of 77.1%, 85.7%, and 72.9% respectively. Multivariate direct discriminant function analysis classified skull bones into male and female with highest levels of accuracy. Using stepwise discriminant function analysis, the most dimorphic variable to determine sex of the skull, was biauricular breadth followed by weight. Subjecting the best dimorphic variables to univariate discriminant analysis, high levels of accuracy of sexual dimorphism was obtained. Percentage classification of high accuracies were obtained in this study indicating high level of sexual dimorphism in the crania, setting specific discriminant equations for the gender determination in South Indian people.

Sexual dimorphism of the mandible in a contemporary Chinese Han population

A present limitation of forensic anthropology practice in China is the lack of population-specific criteria on contemporary human skeletons. In this study, a sample of 203 maxillofacial Cone beam computed tomography (CBCT) images, including 96 male and 107 female cases (20–65 years old), was analyzed to explore mandible sexual dimorphism in a population of contemporary adult Han Chinese to investigate the potential use of the mandible as sex indicator. A three-dimensional image from mandible CBCT scans was reconstructed using the SimPlant Pro 11.40 software. Nine linear and two angular parameters were measured. Discriminant function analysis (DFA) and logistic regression analysis (LRA) were used to develop the mathematics models for sex determination. All of the linear measurements studied and one angular measurement were found to be sexually dimorphic, with the maximum mandibular length and bi-condylar breadth being the most dimorphic by univariate DFA and LRA respectively. The cross-validated sex allocation accuracies on multivariate were ranged from 84.2% (direct DFA), 83.5% (direct LRA), 83.3% (stepwise DFA) to 80.5% (stepwise LRA). In general, multivariate DFA yielded a higher accuracy and LRA obtained a lower sex bias, and therefore both DFA and LRA had their own advantages for sex determination by the mandible in this sample. These results suggest that the mandible expresses sexual dimorphism in the contemporary adult Han Chinese population, indicating an excellent sexual discriminatory ability. Cone beam computed tomography scanning can be used as alternative source for contemporary osteometric techniques.

Multigenerational perceptions of the academic work environment in higher education in the United States

The current workforce composition of the academy is comprised of multiple generational cohorts, Traditionalists, Leading Edge Boomers, Trailing Edge Boomers, Generation Xers and Millennials. Despite the plethora of research identifying a myriad of differences in the way these generational cohorts approach work and social activities little attention has been paid to their perceptions of the psychosocial aspects of the academic work environment. The present study used the Copenhagen Psychosocial Questionnaire II to assess job perceptions of 434 academic personnel across four generational cohorts. A direct discriminant function analysis revealed Trailing Edge Boomers perceived a greater effort-reward imbalance than Traditionalists/Leading Edge Boomers and Generation Xers, and Millennials perceive less imbalance than all other generations. There were also generational group differences in perceived stress and health. These results draw attention to the value of knowing the generational composition of a higher education institution in order to take into account the unique needs of each generational cohort when planning ways to improve recruitment, retention, and productivity of administrators, faculty and staff.

Estimation of sex from the metric assessment of digital hand radiographs in a Western Australian population

The forensic anthropologist is responsible for contributing to the identification of an unknown by constructing a biological profile from their skeletal remains. Towards achieving this goal, anthropologists can apply population and temporally specific standards with known error margins to morphometric data collected from a decedent. Recent research relating to the formulation of sex estimation standards has focussed on the assessment of bones other than the traditionally favoured pelvis and cranium, such as long bones of the appendicular skeleton. In particular, sex estimation standards based on morphometric data from metacarpals and phalanges have reported classification accuracy rates of 80% (and above) based on a narrow range of populations. The purpose of this study is to provide population-specific hand bone sex-estimation standards for a contemporary Western Australian population.The present study examines digital right hand radiographs of 300 adults of known age, equally represented by sex. A total of 40 measurements were taken in each hand (metacarpals and proximal phalanges); the measurements were then analysed using univariate statistics and cross-validated direct and stepwise discriminant function analysis. All hand bone measurements were significantly sexually dimorphic, with a tendency for the width measurements to express a higher degree of dimorphism than the length measurements. A maximum cross-validated classification accuracy of 91% was achieved with a sex bias of -6%. The standards presented here can be used in future forensic investigations that require sex estimation of hand bones in a Western Australian population.

OC-017 A Discriminant Analysis Demonstrates that Siblings of Patients with Crohn’S Disease have a Distinct Microbiological and Immune Phenotype Compared with Healthy Controls: Insights into Disease Pathogenesis

Introduction Crohn’s disease (CD) is associated with genetic risk, intestinal dysbiosis, altered blood T-cell phenotype, increased faecal calprotectin (FC) and intestinal permeability (IP). Factors shared by CD patients and unaffected siblings may be implicated in CD pathogenesis. Aims Delineate the genetic, immune and microbial phenotype of patients, siblings and healthy controls (HC); identify factors associated with CD that discriminate siblings from HC. Methods Faecal microbiota, FC, blood T-cell phenotype, IP and genotype risk over 72 CD risk loci, were measured by qPCR, ELISA, flow cytometry, sugar permeability and Illumina Bead Array respectively, in 22 patients with inactive CD, 21 of their healthy siblings and 25 HC. Results In addition to genotype risk, siblings shared aspects of the phenotype of CD patients, distinct from HC, as previously reported.1 Direct discriminant function analysis revealed that the variables maximally separating siblings from HC (Function 2) were: increased β7 integrin expression by circulating naive CD4+ T-cells and an increased proportion of memory CD4+ T-cells as well as reduced faecal Roseburia spp. (Image 1). In contrast, the variables differentiating CD patients from HC (Function 1) were: elevated FC and altered faecal microbiota (reduced Faecalibacterium prausnitzii , Cluster IV Ruminococcus spp. Bacteroides-Prevotella and Clostridial cluster IV). Conclusion Healthy siblings of CD patients manifest immune and microbiological abnormalities associated with CD, distinct from their genetic risk. Unaffected siblings of CD patients are an excellent model in which to investigate early CD pathogenesis. Disclosure of Interest None Declared Reference Hedin et al. Gut 2012; 61: Suppl. 2 A22-A23.

Sexual dimorphism in ulna: an osteometric study from India.

Determination of sex constitutes the most important element during the identification process of human skeletal remains. Several sex-specific features of human skeleton have been exploited for sex determination with varying reliability. This study aims to obtain sexual dimorphic standards for ulnae of the north Indian population. Eight measurements were obtained on a sample of 106 ulnae (males--80, females--26) in the age range of 25-65 years. The sexual dimorphism index and demarking points were calculated for all the variables. The data were then subjected to stepwise and direct discriminant function analysis. The best discriminator of sex was the maximum length (84.9%) followed by radial notch width (84%). In stepwise analysis, these two variables were selected and provided an accuracy of 88.7% (M-87.5%, F-92.3%). The proximal end provided a classification rate of 81.1% (M-80%, F-84.6%) with selection of the notch length and olecranon width.

Estimation of sex from hand and handprint dimensions in a Western Australian population

A number of recent studies have demonstrated that sex can be estimated with a high degree of expected accuracy through the analysis of anthropometric measurements of the hand. Presently, however, the majority of previous related research has been focused on a limited range of global populations. The aim of the present study, therefore, is to evaluate the accuracy of using anthropometric hand measurements for the estimation of sex in a contemporary adult Western Australian population; we also assess if sex can be accurately estimated from the measurement of handprints. The study sample comprises a total of 91 male and 110 female individuals; documented mean age for the males is 38 years (range 19-68) and for the female sample it is 36 years (range 18-63). A total of six linear measurements are taken from each hand and its corresponding print. Measurement data is analysed using basic univariate statistics and a series of direct and stepwise discriminant function analyses are performed to assess the sex classification potential of the hand and handprint variables. All six hand and handprint measurements are sexually dimorphic and sex explains 28.4-61.7% of the sample variance. The breadth and length of the hand contribute most significantly to sex discrimination; cross-validated sex classification accuracies range between 82.6 and 96.5% with a sex bias of ≤5%. We conclude that anthropometric measurements of the hand and handprint can be used to classify sex with a high degree of expected accuracy in a Western Australian population.

An Osteometric Study of Northern Indian Populations for Sexual Dimorphism in Craniofacial Region

Sex identification is an initial crucial objective in the revelation of the complete identity of the human skeleton as it also renders significantly clearer guidance towards age and stature estimation. Population specific standards are of great practical relevance in the present era of increasing population intermixing. Size differences and robusticity are the two well-elaborated pillars holding most of the dimorphic burdens of the skull. This study is designed to explore dimorphic characteristics of the craniofacial region to establish anthropometric standards for contemporary North Indian populations, which have not been available so far. One hundred and twelve adult crania of known age (23-65 years) and sex (M:F; 82:30) were collected in the Department of Forensic Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India. Ten standard metric parameters of craniofacial region were measured and subjected to stepwise and direct discriminant function analysis employing SPSS 16.00. Bizygomatic breadth emerged as the single best parameter in stepwise analysis, providing an average accuracy of 85.5%.

Psychosocial Factors of Stages of Change Among Adults With Intellectual Disabilities

Relationships among full constructs of the transtheoretical model using a sample of 121 adults with mild intellectual disabilities in Taiwan were examined. Self-reports of stages of change and transtheoretical model psychosocial measures were gathered through interviews. Although MANCOVA revealed that behavioral processes of change, cognitive processes of change, self-efficacy, and perceived pros increased across stages, we did not find a clear linear pattern of association. Direct discriminant function analysis indicated that the most important predictors of stages of change were behavioral processes, cognitive processes, and self-efficacy. The overall stage of change classification accuracy using transtheoretical model psychosocial constructs was 56.2%. Psychosocial measures specifically developed for this population should be further explored.

Establishing Construct Validity of a Stages-of-Change Algorithm for Physical Activity

Examine the construct validity of a modified stages-of-change (SOC) scale among adults with physical disabilities by investigating the relations among the transtheoretical model (TTM) constructs, physical activity (PA), and SOC. Additionally, the SOC algorithm was compared with previously recommended SOC scales. Cross-sectional online survey. 271 adults with physical disabilities (x(age) = 49.25; 73.4% females). Standardized questionnaires for the TTM constructs and PA. ANALYSES/RESULTS: Based on the multivariate analysis of variance, the hypothesized relations between the SOC and the TTM constructs were supported. According to the analysis of variance, PA levels increased almost linearly across the SOC. Precontemplators (x = 8.53 metabolic equivalent [MET]-h/d) had lower PA scores than contemplators (x = 14.27 MET-h/d) and preparators (x = 17.64 MET-h/d), who in turn had lower scores than those in action (x = 23.03 MET-h/d). Based on the direct discriminant function analysis, all TTM constructs were important predictors of the SOC (e.g., r = .85 for behavioral processes; r = .69 for self-efficacy; and r = .58 for cognitive processes). The most accurately predicted SOC were action (76.9%), precontemplation (70.6%), contemplation (44.6%), and preparation (14.9%), with an overall classification accuracy of 56.8%. The study participants were more evenly distributed across the SOC algorithm compared with previous studies. The construct validity of the SOC scale was supported. The scale differentiated almost linearly the levels of PA and most TTM constructs, and participants were well-represented across SOC. Health promoters should feel confident in using the proposed SOC scale and the TTM to implement stage-matched PA motivational programs.

Sex determination from the radius and ulna in a modern South African sample

With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.