Ancestry Assessment Using Random Forest Modeling, ,

A skeletal assessment of ancestry relies on morphoscopic traits and skeletal measurements. Using a sample of American Black (n = 38), American White (n = 39), and Southwest Hispanics (n = 72), the present study investigates whether these data provide similar biological information and combines both data types into a single classification using a random forest model (RFM). Our results indicate that both data types provide similar information concerning the relationships among population groups. Also, by combining both in an RFM, the correct allocation of ancestry for an unknown cranium increases. The distribution of cross‐validated grouped cases correctly classified using discriminant analyses and RFMs ranges between 75.4% (discriminant function analysis, morphoscopic data only) and 89.6% (RFM). Unlike the traditional, experience‐based approach using morphoscopic traits, the inclusion of both data types in a single analysis is a quantifiable approach accounting for more variation within and between groups, reducing misclassification rates, and capturing aspects of cranial shape, size, and morphology.     

Morphoscopic Trait Expression in “Hispanic” Populations

This study evaluates population variation of eight cranial morphoscopic traits using samples of known southwest Hispanics (n = 72), Guatemalans (n = 106), American Blacks (n = 146), and American Whites (n = 218). We applied the support vector machine (SVM) method to build a prediction model based on a subsample (20%) of the data; the remainder of the data was used as a test sample. The SVM approach effectively differentiated between the four groups with correct classification rates between 72% (Guatemalan group) and 94% (American Black group). However, when the Guatemalan and southwest Hispanic samples were pooled, the same model correctly classified all groups with a higher degree of accuracy (American Black = 96%; American White = 77%; and the pooled Hispanic sample = 91%). This study also identified significant differences between the two Hispanic groups in six of the eight traits using univariate statistical tests. These results speak to the unique population histories of these samples and the current use of the term “Hispanic” within forensic anthropology. Finally, we argue that the SVM can be used as a classification model for ancestry estimation in a forensic context and as a diagnostic tool may broaden the application of morphoscopic trait data for the assessment of ancestry.     

The Heritability of Palatal Rugae Morphology Among Siblings*†

Although there is clinical applicability of the palatal rugae as an identification tool in forensic odontology, controversy exists whether the palatal rugae patterns are stable or variable. The greater the genetic component, the higher the probability that palatal rugae patterns are stable. The aim of this study was to compare the palatal rugae morphology between full siblings and the proportion of variability due to genetic component. This cross-sectional study was conducted on digital models of 162 siblings aged 15–30 years old. The palatal rugae patterns were assessed with Thomas and Kotze (1983) classification using Geomagic Studio software (3D Systems, Rock Hill, SC). The palatal rugae morphology between siblings showed significantly similar characteristics for total number of left rugae (p = 0.001), left primary rugae (p = 0.017), secondary rugae for right (p = 0.024) and left sides (p = 0.001), right straight rugae (p = 0.010), and right convergent rugae (p = 0.005) accounting for at least 6.25%-12.8% of the variability due to heredity. Despite the similarities found, the palatal rugae patterns showed significant differences between siblings of at least 46.9% (p = 0.001). Zero heritability was found in 9 of the 14 rugae patterns. Meanwhile, total number of rugae, primary, backward, and convergent rugae showed moderate heritability (h² > 0.3) and total number of secondary rugae showed high heritability (h² > 0.6). In conclusion, despite the individuality characteristics, an appreciable hereditary component is observed with significant similarities found between sibling pairs and the palatal rugae patterns were both environmentally and genetically influenced.     

Weight of authorship evidence with multiple categories of stylometric features: A multinomial-based discrete model

This study empirically demonstrates the efficacy of a two-level Dirichlet-multinomial statistical model (the Multinomial system) for computing likelihood ratios (LR) for linguistic, textual evidence with multiple stylometric feature types with discrete values. The LRs are calculated separately for each feature type, namely, word, character and part of speech N-grams (N = 1,2,3), which are combined as overall LRs through logistic regression fusion. The Multinomial system’s performance is compared with that of a previously proposed system with the cosine distance (the Cosine system) using the same data (i.e., documents collated from 2160 authors). The experimental results show that: (1) the Multinomial system outperforms the Cosine system with the fused feature types by a log-LR cost of ca. 0.01 ～ 0.05 bits; and (2) the Multinomial system is more advantageous in performance with longer documents than the Cosine system. Although the Cosine system is more robust overall against the sampling variability arising from the number of authors included in the reference and calibration databases, the Multinomial system can achieve reasonable stability in performance; for example, the standard deviation value of the log-LR cost becomes lower than 0.01 (10 random samplings of authors for the reference and calibration databases) with 60 or more authors in each database.     

Elaborating on the Construct Validity of the Levenson Self-Report Psychopathy Scale in Incarcerated and Non-Incarcerated Samples

The Levenson Self-Report Psychopathy Scale (LSRP) is a promising, efficient measure of the psychopathic personality. Previous examinations of its latent structure have yielded inconsistent results; therefore, the goal of the current study was to evaluate previously reported two- and three-factor models in three separate groups of male correctional inmates (n = 573), male college students (n = 202), and female college students (n = 200). Confirmatory factor analyses revealed that the best-fitting model across all the three groups was the three-factor model proposed by Brinkley et al. (Assessment 15:464–482, 2008). The convergent and discriminant validity of this three-factor structure as well as a revised 19-item total score were elaborated on in terms of predicting scores on conceptually relevant external criteria. The LSRP total and factor scales evidenced good convergent and discriminant validity with a few notable exceptions. Implications for theory and future research are discussed.     

Population data for 94 identity SNPs in four U.S. population groups

The U.S. National Institute of Standards and Technology (NIST) sequenced 1036 human DNA samples from four United States population groups (African American, Asian, Hispanic, and Caucasian) using the ForenSeq DNA Signature Prep Kit with Primer Mix B (DPMB) on a MiSeq FGx instrument. In addition to STR markers, DPMB includes amplification primers for single nucleotide polymorphisms (SNPs) used for individual identification (iiSNPs, n = 94), ancestry inference (aiSNPs, n = 56), and phenotype prediction (piSNPs, n = 22). Resulting sequencing coverage information was interpreted for the 94 iiSNP markers. Here we present performance characteristics of the ForenSeq DNA Signature Prep Kit in the population studied.     

Progress Toward the Determination of Correct Classification Rates in Fire Debris Analysis,,

Principal components analysis (PCA), linear discriminant analysis (LDA), and quadratic discriminant analysis (QDA) were used to develop a multistep classification procedure for determining the presence of ignitable liquid residue in fire debris and assigning any ignitable liquid residue present into the classes defined under the American Society for Testing and Materials (ASTM) E 1618‐10 standard method. A multistep classification procedure was tested by cross‐validation based on model data sets comprised of the time‐averaged mass spectra (also referred to as total ion spectra) of commercial ignitable liquids and pyrolysis products from common building materials and household furnishings (referred to simply as substrates). Fire debris samples from laboratory‐scale and field test burns were also used to test the model. The optimal model's true‐positive rate was 81.3% for cross‐validation samples and 70.9% for fire debris samples. The false‐positive rate was 9.9% for cross‐validation samples and 8.9% for fire debris samples.     

Comparative Analysis of Insect Succession Data from Victoria (Australia) Using Summary Statistics versus Preceding Mean Ambient Temperature Models

Minimum postmortem interval (mPMI) can be estimated with preceding mean ambient temperature models that predict carrion taxon pre‐appearance interval. But accuracy has not been compared with using summary statistics (mean ± SD of taxon arrival/departure day, range, 95% CI). This study collected succession data from ten experimental and five control (infrequently sampled) pig carcasses over two summers (n = 2 experimental, n = 1 control per placement date). Linear and exponential preceding mean ambient temperature models for appearance and departure times were constructed for 17 taxa/developmental stages. There was minimal difference in linear or exponential model success, although arrival models were more often significant: 65% of linear arrival (r² = 0.09–0.79) and exponential arrival models (r² = 0.05–81.0) were significant, and 35% of linear departure (r² = 0.0–0.71) and exponential departure models (r² = 0.0–0.72) were significant. Performance of models and summary statistics for estimating mPMI was compared in two forensic cases. Only summary statistics produced accurate mPMI estimates.     

A Preliminary Investigation into the Accuracy of 3D Modeling and 3D Printing in Forensic Anthropology Evidence Reconstruction,

There is currently no published empirical evidence‐base demonstrating 3D printing to be an accurate and reliable tool in forensic anthropology, despite 3D printed replicas being exhibited as demonstrative evidence in court. In this study, human bones (n = 3) scanned using computed tomography were reconstructed as virtual 3D models (n = 6), and 3D printed using six commercially available printers, with osteometric data recorded at each stage. Virtual models and 3D prints were on average accurate to the source bones, with mean differences from ?0.4 to 1.2 mm (?0.4% to 12.0%). Interobserver differences ranged from ?5.1 to 0.7 mm (?5.3% to 0.7%). Reconstruction and modeling parameters influenced accuracy, and prints produced using selective laser sintering (SLS) were most consistently accurate. This preliminary investigation into virtual modeling and 3D printer capability provides a novel insight into the accuracy of 3D printing osteological samples and begins to establish an evidence‐base for validating 3D printed bones as demonstrative evidence.     

Utility of Postmortem Vitreous Beta-Hydroxybutyrate Testing for Distinguishing Sudden from Prolonged Deaths and for Diagnosing Ketoacidosis

A retrospective, cross-sectional analysis of vitreous beta-hydroxybutyrate (BHB) on 967 forensic cases over a two-year period was conducted. Cases were sorted into six categories of death: (i) sudden traumatic/non-natural (ST), (ii) sudden natural (SN), (iii) prolonged traumatic/non-natural (PT), (iv) prolonged natural (PN), (v) diabetic ketoacidosis (DKA), and (vi) alcoholic ketoacidosis (AKA). The mean BHB for all cases was 1.67 mmol/L (17.4 mg/dL; range: 0.11–18.02 mmol/L). The numbers of DKA, AKA, PN, PT, SN, and ST deaths were 21, 5, 155, 258, 275, and 253, respectively. Their mean vitreous BHBs were as follows: 11.04 mmol/L (DKA), 8.88 mmol/L (AKA), 1.56 mmol/L (PN), 1.55 mmol/L (PT), 1.26 mmol/L (SN), and 1.38 mmol/L (ST). There was a statistically significant difference between the mean BHBs of the PN and SN death groups (p < 0.001), as well as between those of the PT and ST death groups (p = 0.004). Given the overlapping ranges seen between the prolonged and sudden death groups, the identified differences did not hold clinical significance. In addition, we sought to determine a threshold value for vitreous BHB to definitely diagnose cases of ketoacidosis. BHB threshold concentrations between 2.5 and 5 mmol/L produced sensitivities >92% and specificities >96%. A receiver operator characteristic curve found 3.43 mmol/L to be the optimal cutoff value, demonstrating a specificity of 98.3% and a sensitivity of 96.2%.     

Development and validation of highly selective screening and confirmatory methods for the qualitative forensic analysis of organic explosive compounds with high performance liquid chromatography coupled with (photodiode array and) LTQ ion trap/Orbitrap mass spectrometric detections (HPLC-(PDA)-LTQOrbitrap)

An LTQ-Orbitrap FTMS is a new (hybrid) mass spectrometric (MS) analyzer. It allows for the acquisition of full scan MSⁿ (n-stage fragmentations, n = 1 − n) spectra with the linear ion trap detector (LTQ) at high speed and/or with the Fourier Transform-detector (Orbitrap) with ultra high mass resolution (> 60,000 at m/z < 400 amu) and high mass accuracy (≤ 1 ppm with internal calibration). In addition it may be coupled with liquid chromatography (LC) with photo diode array (PDA) detection.Two methods for the forensic screening and confirmation of all common trace explosives in post-blast residues have been developed on this instrument using atmospheric pressure chemical ionization (APCI). In one run, the nitrogen-containing explosives are analyzed with the combination of “LC-(PDA)-APCI(−)-LTQ MS²/Orbitrap FTMS” (Method 1). In another run, peroxide explosives are analyzed with “LC-APCI(+)-LTQ MS²/Orbitrap FTMS” (Method 2).The performance of both methods has been validated according to procedures defined in the EU COMMISSION DECISION implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results (DC 2002/657/EC) and other standards (NEN 17025 and NEN 7777). The methods are highly selective due to the simultaneous utilization of the Orbitrap FTMS and LTQ MS², both of which are highly selective detectors Tested explosive compounds can be detected in the molecular ion form by the Orbitrap analyzer with minimal mass interference in different matrices when using an extremely narrow mass tolerance detection window (≤ 2 ppm). The identification of a detected compound follows an identification point system. Experimental results show that almost all explosive compounds meet the confirmation criteria (minimum 4 points) required for the positive identification by the DC 2002/657/EC.     

Passive Drip Stain Formation Dynamics of Blood onto Hard Surfaces and Comparison with Simple Fluids for Blood Substitute Development and Assessment,

The spreading dynamics of blood dripping onto hard surfaces is compared to two spreading models. Samples of human blood, porcine blood, and Millipore^® water were dripped onto cardboard, foamcore, and glass surfaces in low velocity passive drip simulations. Final stain diameter, the total number of spines and scallops, and angle of impact were measured and analyzed. Spreading is best predicted by applying the concept of effective viscosity to the Scheller and Bousfield (R² = 0.91) and Roisman (R² = 0.89) spreading models. In the tested conditions, blood spreads with Newtonian tendencies; however, has quantifiable differences in stain appearance to Newtonian fluids like water. This is encouraging for the development of water‐based fluids as synthetic blood substitutes (SBSs). The work presents an assessment platform to quantify and score the performance of simple water‐based fluids using final stain diameter (6 points) and number of spines and scallops (6 points) at six dripping heights between 20 and 120 cm. The angle of impact of a stain alone is not a sensitive measure of SBS performance, but stain formation scores the SBS's performance with another 1 point. Together these features generate a quantitative relative ranking system, of a maximum possible 13 points, that can be used to support the use of a particular fluid for the creation of a drip stain. The performance of twenty simple fluids in the simulated dripping assessment test is described.     

The accuracy and reliability of the Suchey–Brooks pubic symphysis age estimation method: Systematic review and meta-analysis

Suchey–Brooks method has been studied many times with varying reports of accuracy and reliability. A systematic review and meta-analyses were utilized to quantitatively determine the accuracy and reliability of the Suchey–Brooks (S-B) method. A systematic search of PubMed and EBSCO health and medical databases was performed. Meta-analyses were performed to quantify the relationship between actual known age at death and the S-B method using Spearman's Rho and Pearson's r for (1) combined males and females estimates, (2) male-only estimates, and (3) female-only estimates. Overall correlation coefficient using Cohen's kappa, Spearman's Rho, and Pearson's r was also calculated to determine the interrater and intrarater reliability using the S-B method. Eighteen studies classified as moderate-to-high methodological quality met the inclusion criteria. The sample sizes were different for the combined male and female (n = 2620), male-only (n = 2602), and female-only (n = 1431) meta-analyses. The effect size of the age at death meta-analyses was large and significant for combined males and females (Spearman's Rho = 0.62; Pearson's r = 0.65), male-only (Spearman's Rho = 0.77; Pearson's r = 0.75), and female-only (Spearman's Rho = 0.71; Pearson's r = 0.71). The overall correlation coefficients of the interrater (Kappa = 0.76; Spearman's Rho = 0.73; Pearson's r = 0.80) and intrarater (Kappa = 0.81; Spearman's Rho = 0.91; Pearson's r = 0.83) reliability meta-analyses were large and significant. A significant degree of heterogeneity was present in all meta-analyses, with minimal evidence of publication bias. The meta-analyses results suggest the S-B method is highly reliable with a moderate-to-high degree of accuracy. Our results also identified sample size and accuracy differences between male and female individuals.     

Causes of Sudden Death in Patients with Obstructive Sleep Apnea

There are few autopsy studies of patients dying suddenly with obstructive sleep apnea (OSA). Twenty‐five forensic autopsies of unexpected sudden death in individuals with OSA were reviewed. The causes of death were as follows: cardiomyopathy (n = 11); sudden unexpected death without morphologic findings (SUDNA, n = 6); and other cardiovascular diseases not related to OSA (n = 8). The cardiomyopathy group comprised five hearts with concentric left ventricular hypertrophy without dilatation and six with left ventricular diameter >4 cm (dilated cardiomyopathy). Four of six hearts in the SUDNA group showed right ventricular dilatation compared with seven of 11 showed cardiomyopathy and one of eight miscellaneous. The degree of obesity was greatest in the dilated cardiomyopathy group (10 of 11 obese) followed by the SUDNA group (four of six obese). The cardiac findings in patients dying suddenly and unexpectedly with OSA include nonspecific cardiomyopathy, other cardiac conditions, and hearts without a morphologic cause of death, which show frequent right ventricular dilatation as the only finding.     

Determination of Nitrite in Whole Blood by High‐Performance Liquid Chromatography with Electrochemical Detection and a Case of Nitrite Poisoning

Although nitrite is widely used in meat processing, it is a major toxicity hazard to children and is responsible for the blue‐baby syndrome. A simple and effective method to determine nitrite in whole blood has been devised using ion chromatography with suppressed conductivity detection. The blood sample was deproteinized by adding acetonitrile and purified with mini‐cartridges to remove hydrophobic compounds, chloride ions, and metal ions. An aliquot of the filtrate was injected onto the ion chromatography. The retention time for nitrite was 13.8 min and the detection limit of nitrite in whole blood was 0.4 μmol/L. The calibration curve was linear (r² = 0.9999) over the concentration working range. The blood nitrite concentration of a victim who attempted suicide by ingesting sodium nitrite powder was determined using the present method. The basal levels for nitrite in human blood was determined with 7.1 ± 0.9 μmol/L (n = 12).     

Attachment Models in Incarcerated Sex Offenders: A Preliminary Italian Study Using the Adult Attachment Interview

A group of sex offenders (clinical group: n = 19) was compared to a nonclinical sample matched by age, years of education, and gender (control group A: n = 19) to verify a higher incidence of insecure attachment models among sex offenders. In addition, we tested whether sex offenders were characterized by specific childhood experiences, compared to control adults (control group B: n = 19) with the same secure/insecure attachment classification. Results showed significant differences between offenders and control adults on both the AAI continuous score and the distribution of the two-way attachment classifications. Furthermore, sex offenders reported more intense experiences of rejection by the father figure and abuse in the family context during early childhood compared to not offenders subjects with the same attachment classification.     

A Direct Aqueous Derivatization GSMS Method for Determining Benzoylecgonine Concentrations in Human Urine

A sensitive and reliable method for extraction and quantification of benzoylecgonine (BZE) and cocaine (COC) in urine is presented. Propyl‐chloroformate was used as derivatizing agent, and it was directly added to the urine sample: the propyl derivative and COC were then recovered by liquid–liquid extraction procedure. Gas chromatography–mass spectrometry was used to detect the analytes in selected ion monitoring mode. The method proved to be precise for BZE and COC both in term of intraday and interday analysis, with a coefficient of variation (CV) <6%. Limits of detection (LOD) were 2.7 ng/mL for BZE and 1.4 ng/mL for COC. The calibration curve showed a linear relationship for BZE and COC (r² >0.999 and >0.997, respectively) within the range investigated. The method, applied to thirty authentic samples, showed to be very simple, fast, and reliable, so it can be easily applied in routine analysis for the quantification of BZE and COC in urine samples.     

Using Paint to Investigate Fires: An ATR‐IR Study of the Degradation of Paint Samples Upon Heating

Fire investigation is a challenging area for the forensic investigator. The aim of this work was to use spectral changes to paint samples to estimate the temperatures to which a paint has been heated. Five paint samples (one clay paint, two car paints, one metallic paint, and one matt emulsion) have been fully characterized by a combination of attenuated total reflectance Fourier transform infrared (ATR‐IR), Raman, X‐ray fluorescence spectroscopy and powder X‐ray diffraction. The thermal decomposition of these paints has been investigated by means of ATR‐IR and thermal gravimetric analysis. Clear temperature markers are observed in the ATR‐IR spectra namely: loss of ν(C = O) band, >300°C; appearance of water bands on cooling, >500°C; alterations to ν(Si–O) bands due to dehydration of silicate clays, >700°C; diminution of ν(CO₃) and δ(CO₃) modes of CaCO₃, >950°C. We suggest the possible use of portable ATR‐IR for nondestructive, in situ analysis of paints.     

Nonmetric Cranial Trait Variation and Ancestry Estimation in Asian and Asian-Derived Groups

Traditionally, precontact Native Americans and Asian groups have been conflated for aspects of the biological profile due to their distantly shared genetic history, although this grouping remains largely unexplored. This study examines craniomorphic variability to ascertain whether Asian groups can be differentiated from each other and from Asian-derived groups using more fine-tuned models. Cranial and mandibular data for 35 nonmetric traits were recorded on precontact Native Americans (n = 150) and modern Japanese (n = 150) and Thai (n = 150) individuals. Chi-square analyses indicate that all groups exhibit statistically significant differences in most traits. Additionally, cross-validated binary logistic regression equations resulted in correct classification rates in the range of 65.0–93.3% and demonstrate that sex does not contribute to statistical models. Therefore, numerous traits provide discriminatory resolution that detects differences between the samples, thus highlighting the potential utility of nonmetric traits in identifying individuals beyond the traditional African, European, and Asian forensic ancestry groupings.