The over-citation of Daubert in forensic anthropology.

The 1993 US Supreme Court decision Daubert v. Merrell Dow Pharmaceuticals, Inc. presented new guidance for the judicial assessment of expert witness evidence and testimony in the determination of admissibility. Despite the rarity of admissibility challenges to forensic anthropology evidence, Daubert is frequently cited in published forensic anthropology research. This study undertook a qualitative thematic analysis of forensic anthropology articles published in the Journal of Forensic Sciences to assess why authors continue to cite Daubert and express concerns over potential exclusion. The results show a significant increase in the number of articles that cite legal admissibility standards over time (p < 0.001). Authors frequently cite these standards to contextualize their results within the Daubert framework or to justify the need for their research. Notably, many articles present Daubert as a constraining force, misinterpreting the guidelines as rigid criteria or that they require methods to be strictly quantitative. However, Daubert was intended to be a flexible tool for judges-not a standard or instruction for scientists. While it was reasonable to reflect on the scientific rigor of methods in the wake of the Daubert decision, a new perspective is warranted in which forensic anthropologists shift their focus from trying to "satisfy" admissibility guidelines to adopting quality assurance measures that minimize error and ensure confidence in analytical results, and developing and using methods that are grounded in good science-which is important regardless of whether or not the results are ever the subject of a trial.

Reconstruction of full femora from partial bone fragments for anthropological analyses using statistical shape modeling.

OBJECTIVES: Due to taphonomic processes such as burial, fire, or animal activity, bones are often found incomplete, which can pose problematic for establishing the biological profile of the deceased using anthropological methods. The aim of this study is to test the feasibility of using statistical shape modeling (SSM) to reconstruct full femora from simulated partial femora and determine the accuracy of the reconstruction. Moreover, we assess the accuracy of sex estimation and the degree of stature error added based on the reconstructed femur using different anthropological methods. METHODS: A total of 42 (28 female, 14 female) 3D models of left femora extracted from computed tomography (CT) scans were used. We performed a leave-one-out cross-validation (LOOCV) where 41 bones were used to build the SSM and one bone was used for testing. This bone was cut in 1 cm steps proximally, distally and from both ends up to 10 cm, reconstructed using SSM, and tested using the methods established by Stewart and Purkait (2005), Trotter and Gleser (1952), as well as a method based on SSM. with landmarks being automatically identified. RESULTS: The error induced by reconstructing the femur to the length measurements was low, which translated into useful stature estimations (single sided cuts up to 10 cm: 0.4-1.1%, double sided<2% for cuts shorter than 6 cm). Using Purkaits method for sex estimation on reconstructed bones looked promising as well (single sided: 90.5% when compared to applying Purkaits method on the original bone, double sided 78.6% (10 cm cut) to 97.6% (1-3 cm cuts)) Using SSM for sex classification looked promising as well (single sided cut: 81-85.7%, double sided cut: 59.5-85.3%) CONCLUSION: SSM can be used to reconstruct fragmented femora. These reconstructions can be used for sex and stature estimations, at the cost of lower accuracy. Using SSM might give investigators an additional tool to gain information about the biological profile of a deceased in cases where the fragmentation of a femur does not allow for using other anthropological methods.

Detection of bone particles in non-carbonate soils.

A routine geologic test for the presence of carbonate minerals in soil is the application of dilute hydrochloric acid (HCl) and observation for an effervescent reaction. This study tests whether non-carbonate soils can exhibit effervescence in the presence of HCl if bone particles are present in the soil. Five bone fragments displaying various taphonomic alterations were ground and sieved to achieve uniform particle size fractions. A non-carbonate soil was mixed with each bone particle fraction, and 1 molar HCl solution was applied while observing the reaction using a stereo microscope. All tests resulted in the effervescence of bone particles, which could be easily located within the soil based on the presence of small bubbles surrounding the bone particle. These results show that a simple, quick, cost-effective test can be used to presumptively determine whether soil may contain bone particles, even if they are too small to be identified morphologically. Results also suggest that, since bone particles in soil can produce the same type of effervescence expected in carbonate soil, additional tests may be needed to determine the source of an effervescent reaction. These findings also highlight the insight that can be gained through interdisciplinary discussions and investigations.

CT-based sex estimation on human femora using statistical shape modeling.

OBJECTIVES: Estimating the sex of decomposed corpses and skeletal remains of unknown individuals is one of the first steps in the identification process in forensic contexts. Although various studies have considered the femur for sex estimation, the focus has primarily been on a specific single or a handful of measurements rather than the entire shape of the bone. In this article, we use statistical shape modeling (SSM) for sex estimation. We hypothesize that the accuracy of sex estimation will be improved by using the entire shape. MATERIALS AND METHODS: For this study, we acquired a total of 61 femora from routine postmortem CT scans at the Institute for Forensic Medicine of the University of Zurich. The femora were extracted using segmentation technique. After building a SSM, we used the linear regression and nonlinear support vector machine technique for classification. RESULTS: Using linear logistic regression and only the first principal component of the SSM, 76% of the femora were correctly classified by sex. Using the first five principal components, this value could be increased to 80%. Using nonlinear support vector machines and the first 20 principal components increased the rate of correctly classified femora to 87%. DISCUSSION: Despite some limitations, the results obtained by using SSM for sex estimation in femur were promising and confirm the findings of other studies. Sex estimation accuracy, however, is not significantly improved over single or multiple linear measurements. Further research might improve the sex determination process in forensic anthropology by using SSM.

Use of a Gelatin-based Consolidant to Preserve Thermally-Altered Skeletal Remains.

Thermally altered skeletal remains can be very fragile and fragmented and are typically further fragmented or even destroyed when handled; recovery of such remains from a scene can therefore be extremely challenging. There are few recommendations and no generally accepted practices for preserving burned bone for recovery and transport. Here, we test whether the application of a gelatin-based consolidant at the scene can preserve thermally altered bone in the condition and relative anatomical position in which it was discovered. A solution of Knox® brand gelatin and water was applied to burned pig mandibles using a spray bottle. Qualitative and quantitative analysis indicates that the application of the consolidant significantly decreased fragmentation as compared to untreated controls (p < 0.05), with most of the treated mandibles remaining completely intact after recovery and transport to a secondary location. In addition to the effectiveness for preservation, the method is also easy to apply, inexpensive, and reversible.

Bilateral Asymmetry of Nutrient Foramen Position in Forearm Bones: Implications for its Use in Sorting Commingled Remains.

Commingling is frequently encountered in cases examined by the Committee on Missing Persons in Cyprus, and pair-matching is routinely used as a preliminary segregation method. Here we examine the degree of bilateral asymmetry in nutrient foramen position of the radius and ulna to determine whether nutrient foramen position may be useful in visual and/or ostetometric pair-matching. Differences in nutrient foramen position between left-right pairs from the same individual were compared with differences in nutrient foramen position between different individuals. Bilateral asymmetry in nutrient foramen position was found to be high, indicating that it is not a reliable trait for pair-matching. Bilateral asymmetry and between-person variation were found to differ between the two bones examined, suggesting that nutrient foramen position in other long bones should also be tested.

The Effect of Household Oxidizing Cleaners on Chemiluminescence of Blood Using Bluestar®.

This study tests the effect of three common oxidizing cleaners on the ability of the Bluestar Forensic® presumptive test for blood to identify the presence of blood on ceramic tile after cleaning. The cleaners tested were Lysol®, OxiClean®, and Arm & Hammer®. This study also tested which cleaner was the most effective at removing blood, measured by the intensity of chemiluminescence, which was quantified using RGB values in ImageJ. A "hasty" 1-min cleaning of a blood droplet was simulated using the three cleaners. The chemiluminescence of the Bluestar® reactions after cleaning the blood-treated region was compared to an untreated region of the same tile for each cleaner, as well as to the treated regions of tiles between the three cleaners. Results indicate that none of the three cleaners removed all of the blood (all p < 0.001) and that Lysol® removed more blood compared to the OxiClean® and Arm & Hammer®.

Comparative radiologic identification with standardized single CT images of the paranasal sinuses-Evaluation of inter-rater reliability.

The aim of this study was to assess the reproducibility of a standardized image for personal identification (SIPI), used in the comparative analysis of paranasal sinuses, and test the effect of inaccurate reformation of the SIPI on suitability for comparative identification. Five raters with different professional backgrounds independently reformatted SIPIs from ten post-mortem head CTs. Inter-rater, intra-rater agreement as well angular deviations between reformatted SIPI images and reference SIPI images were calculated. Second, raters assessed the suitability of 70 accurately and inaccurately reformatted SIPIs for identification with a 4-point Likert scale. Inter-rater agreement as well as levels of significance regarding image suitability were calculated. Inter-rater agreement regarding reproducibility of SIPI reformation was excellent (inter-rater correlation coefficient (ICC) 0.9995, intra-rater ICC 0.9983). Deviation between the angular dimensions of the reformatted SIPIs and the reference SIPIs was ≤1° in 94% of all 300 measurements. Inter-rater agreement regarding the effect of inaccurate SIPI reformation on suitability for comparative identification was fair (ICC 0.6809). There was no statistically significant difference between raters' evaluation of image suitability (p=0.9755). This study shows that the standardized image for personal identification can be accurately reformatted by different raters with varying professional backgrounds. In addition, raters agree that inaccurately reformatted SIPIs are still suitable for comparative identification in the majority of cases.

A test of the citrate method of PMI estimation from skeletal remains.

Citrate content in bone has been shown to be associated with the postmortem interval (PMI), with citrate decreasing after death as a function of time. Here we test this method using porcine ribs for the period of 1-165days after death, and also assess citrate content and variation from samples placed into two different postmortem environments (terrestrial and aquatic). Higher citrate variation, lower citrate recovery, and a weaker association with time were found in this study as compared to others. Citrate content, however, was found to decrease with increasing PMI, and the method was found to be easy and inexpensive to apply. No significant differences were found in citrate loss between terrestrial and aquatic environments. Although more research is needed, citrate content appears to be a promising new approach in estimating PMI from skeletal remains.

Effects of Aluminum Foil Packaging on Elemental Analysis of Bone.

Burned skeletal material is often very fragile and at high risk for fragmentation during packaging and transportation. One method that has been suggested to protect bones in these cases is to carefully wrap them in aluminum foil. Traces of aluminum, however, are known to transfer from foil packaging materials to food products. If such transfer occurs between aluminum foil and bones, it could interfere with subsequent chemical, elemental and isotopic analyses, which are becoming more common in forensic anthropological investigations. This study examined aluminum levels in bones prior to and following the use of aluminum foil packaging and storage for a 6-week period. Results indicate no significant change in the detected levels of aluminum (p > 0.05), even when packaged in compromised foil and exposed to elevated temperatures. Aluminum foil can therefore continue to be recommended as a packaging medium without affecting subsequent chemical examinations.

The Effect of Time on Bone Fluorescence: Implications for Using Alternate Light Sources to Search for Skeletal Remains.

Bones fluoresce when exposed to certain wavelengths of shortwave light, and this property can be useful in locating and sorting skeletal remains in forensic contexts. The proteins in bone collagen are largely responsible for its fluorescent properties, but these proteins degrade and denature over time. This study examined the fluorescence of bones from four temporal groups (recent, semi-recent, ancient, and historic) ranging from 0 to 1064 years before present. Specimens were photographed under 490 nm wavelength light, and fluorescence was quantified by converting intensity to a gray scale value based on the RGB color model using ImageJ(®) software. Significant (p < 0.05) differences were found in mean fluorescence between all four temporal groups, and a 0.324 coefficient of correlation indicates a significant (inverse) relationship between fluorescence and time. Bone fluorescence decreases with time, but some fluorescence is retained even in older samples. Fluorescence can therefore be reliably used in many modern skeletal remains searches.

Calcium and Phosphorus Detection Using Benchtop Versus Handheld X-ray Fluorescence Spectrometers.

Elemental analysis of calcium (Ca) and phosphorus (P) has been shown to be useful in differentiating skeletal and nonskeletal material. X-ray fluorescence spectrometry (XRF) is an attractive, nondestructive technique for forensic anthropologists, and the development of portable XRF instrumentation is promising for field applications. This study examines the performance of handheld XRF instrumentation operated in air compared to a traditional benchtop XRF device that has the ability to control the analysis atmosphere. Both instruments can be used to effectively distinguish skeletal from nonskeletal remains. However, as the measurement atmosphere affects detection levels for calcium and phosphorus, Ca/P ratios obtained from the instruments and analysis conditions were found to differ significantly, with analyses conducted in air showing significantly lower phosphorus detection. Consequently, comparison of Ca/P ratios to conclude skeletal versus nonskeletal origin must be based on data collected under similar analysis conditions.

The Use of Femoral Neck Axis Length to Estimate Sex and Ancestry.

Having multiple reliable methods of estimating sex and ancestry from various skeletal features increases the likelihood of identifying skeletal remains. Femoral neck axis length (FNAL), as measured in living individuals, has been shown to vary by sex and ancestry. FNAL has not, however, been previously measured directly from skeletonized remains and investigated for its potential use in forensic anthropological applications. This research proposes a method for measuring FNAL from skeletal remains, determines the reliability and repeatability of the measurement, and assesses the validity of FNAL in sex and ancestry estimation. Results showed low interobserver error in the measurement of FNAL (TEM=0.33 mm, R=0.99). Significant differences in FNAL were found between sexes as well as between American Black, American White, and Native American groups. FNAL can correctly classify sex in ~86% of all cases and is considered valuable to sex estimation. The value of FNAL to ancestry estimation, however, is considered limited.

Elemental Analysis of Variably Contaminated Cremains Using X-ray Fluorescence Spectrometry.

Analyzing and identifying skeletal remains becomes increasingly difficult when remains have been cremated, especially in cases where the cremated material may have been intentionally contaminated with nonskeletal material. This study examined the potential of X-ray fluorescence spectrometry (XRF) to detect the presence of nonskeletal contaminants in samples of cremains. Eleven samples of cremains were variably combined with concrete mix and analyzed using XRF. Photon counts of elements in each sample were analyzed, and the coefficient of determination (R(2)) using unweighted linear regression as a function of percent cremains was calculated. Results showed that with changes in the proportion of skeletal material and contaminant, there were significant (R(2) > 0.90) changes in detected levels of phosphorus, potassium, zinc, aluminum, and sulfur. The use of XRF is concluded to be a valid approach in the identification of the presence of nonskeletal material in potentially contaminated cremains.

The use of an alternate light source for detecting bones underwater.

When searching underwater crime scenes or disaster scenes for fragmentary human remains, it may be advantageous for forensic divers to be able to detect the presence of bones and teeth among other marine materials (such as shells and rocks). In terrestrial environments, this can typically be accomplished by visual and instrumental methods, but underwater conditions make it difficult to employ detection and sorting techniques in these environments. This study investigates fluorescence of bones and teeth and other marine materials using a submersible alternate light source (ALS) and concludes that an ALS can be a useful tool for detecting bones and teeth in underwater searches as well in terrestrial searches and laboratory environments. The results could impact the methods and equipment used by forensic divers and forensic anthropologists when searching for skeletal remains, potentially increasing the quantity and efficiency of forensic evidence recovered.

Ancestral differences in femoral neck axis length: possible implications for forensic anthropological analyses.

In forensic anthropological contexts, very few methods of estimating ancestry from the postcranial skeleton are available. The cranium is widely recognized to show the greatest ancestral variation, and is often regarded by forensic anthropologists as the only reliable bone for estimating ancestry from unidentified skeletal remains. Several studies have demonstrated ancestral variation in aspects of the femur, but none have shown significant predictive power for discriminating multiple groups, and have therefore not gained wide acceptance by forensic anthropologists. Skeletal health experts (particularly bone densitometrists), however, have long recognized a relationship between proximal femur geometry (especially hip axis length) and osteoporosis-related fracture risk. Moreover, fracture risk has been noted to vary between ancestral groups. Here, we investigate whether measurements that are related to fracture risk might also be used to estimate ancestry from unidentified skeletal remains. Specifically, we investigate ancestral differences in femoral neck axis length (FNAL) and find significant differences between European, Asian and African groups in both women and men. FNAL was largest in European groups followed by African and then Asian groups. The greatest discriminating power was found between European and Asian groups, but was also significant between European and African groups. These differences may have utility in estimating ancestry in forensic anthropological contexts.

Neurotrophic keratitis.

Neurotrophic keratitis (NK) is a rare degenerative corneal disease that occurs as a result of partial or total impairment of trigeminal innervations, leading to a reduction (hypoesthesia) in or loss (anaesthesia) of corneal sensitivity. The impairment of sensory innervation causes a reduction in the lacrimation reflex and the vitality, metabolism and mitosis of epithelial cells, with subsequent deficiency in epithelial repair, stromal and intracellular oedema, loss of microvilli, and abnormal development of the basal lamina. Several recent studies have proposed different therapies based on different aetiopathogenetic theories. The aim of the therapy is to treat aetiopathogenesis and, at the same time, promote corneal healing. In this paper, we report the aetiology, diagnosis, management, and medical and surgical treatment of NK, also indicating future treatments based on the most recent studies.

Error and its meaning in forensic science.

The discussion of "error" has gained momentum in forensic science in the wake of the Daubert guidelines and has intensified with the National Academy of Sciences' Report. Error has many different meanings, and too often, forensic practitioners themselves as well as the courts misunderstand scientific error and statistical error rates, often confusing them with practitioner error (or mistakes). Here, we present an overview of these concepts as they pertain to forensic science applications, discussing the difference between practitioner error (including mistakes), instrument error, statistical error, and method error. We urge forensic practitioners to ensure that potential sources of error and method limitations are understood and clearly communicated and advocate that the legal community be informed regarding the differences between interobserver errors, uncertainty, variation, and mistakes.