Age Determination Technique Research Articles

Validation of Age Estimation Using the Compositional Variation of Dental Hard Tissue: An X-ray Diffraction Analysis.

Introduction X-rays and X-ray diffraction (XRD) are two non-destructive techniques that determine a material's crystallographic structure, chemical composition, and physical properties. They can also be used to estimate a person's age when it is unknown, assess the need for orthodontic treatment, or predict the likelihood of tooth decay. This research aims to validate the accuracy of age estimation through X-ray diffraction analysis of tooth hard tissue with compositional changes. Methodology Four tooth samples were analyzed using the Pan Analytical XRD (Malvern Panalytical Ltd., UK) unique d8 family platform, which uses Cu Kα radiation (0.154 nm) and a 0.02° scan rate from 0 to 80°. Results The angle of incidence (ω) is established between the sample and the X-ray source. The angle of diffraction, 2θ, is established between the detector and the incident beam. The detector angle 2θ and the incident angle ω always equal half. Inter-atomic distance, or d-spacing (D = 10^-8 cm in Angstrom units), is measured. A greater crystal size or a greater degree of crystallinity may be indicated by a higher peak intensity, which translates to an increased amount of atoms in the crystal. Conclusion The study's findings suggest that XRD is a promising new technique for age determination, as it has an advanced and dynamic approach to finding the crystallographic characteristics of the provided sample.

Sex and age determination of human mandible using anthropological parameters and TCI and Kvaal methods: study of a Serbian medieval sample.

The aim of the study was to test the efficacy, reliability, and applicability of the Kvaal and Tooth Coronal Index (TCI) age determination techniques, and then to compare them with each other, as well as with the conventional anthropological age and sex determination techniques. The analyzed material originates from the medieval necropolis of the Vinča-Belo brdo site. During the research, 60 periapical (PA) and 30 orthopantomographic (OPT) images were analyzed. On each analyzed tooth, age assessment was performed using both TCI and Kvaal techniques. The obtained values of dental estimated age were compared with age estimated by anthropological analysis, and the deviations between the estimated and chronological age were analyzed in relation to the assessment technique, type of dental radiograph, tooth group, sex, and age. The mean error between TCI and the osteological method was 8.44 (SD = 7.56, Min = 0.169, Max = 36.4) and between Kvaal and the osteological method was 7.71 (SD = 5.57, Min = 0.133, Max = 26.7). The average value of age recorded by TCI method was 32.5years and by Kvaal method was 34.7years. There was no statistically significant difference based on the two radiographic methods, gender, individual teeth, or tooth group pairs. There was a statistically significant positive correlation between age and the error present. Gender determination based only on the mandible has a high correlation with the anthropological gender determination. The Kvaal method and the TCI method have proven their efficiency, reliability, and applicability. Significant correlation has been observed between dental and anthropological age and sex determination methods.

A new age determination technique for rare metal deposits: In situ Sm-Nd dating

A new age determination technique for rare metal deposits: In situ Sm-Nd dating

Development of Age Determination Technique Part 2: Image Processing for Age Determination Based on the Annuli of a Chum Salmon Scale

Development of Age Determination Technique Part 2: Image Processing for Age Determination Based on the Annuli of a Chum Salmon Scale

Development of Age Determination Technique Part 1: Neural-Network Based Prediction of Chum Salmon Age by Scale Images

Development of Age Determination Technique Part 1: Neural-Network Based Prediction of Chum Salmon Age by Scale Images

Lithium abundance is a gravitational model dependent quantity

The dependence of lithium abundance on modified gravity in low-mass stellar objects is demonstrated. This may introduce an additional uncertainty to age determination techniques of young stars and globular clusters if they rely on the light element depletion method.

Advances in fingermark age determination techniques.

Fingermarks have long been recognized as one of the most reliable and valuable evidence for personal identification. In practice, fingerprint analysis primarily concentrates on latent fingerprint visualization. However, fingerprint visualization techniques do not always enable individualization when fingermarks collected in crime scenes are fragmentary, ambiguous, or deformed. Age determination techniques based on physical and chemical composition changes in fingerprints over time have attracted researchers' attention in recent years. Nevertheless, the components of fingerprints are liable to factors including donor features, deposition conditions, substrate properties, environmental conditions and revealing methods. All the influences mainly contribute to unreliable outcomes of age estimation. Recent developments in fingermark age determination have moved forward to more precise approaches. The advanced methods can be classified into two categories including techniques based on the modifications of physical characteristics and chemical composition characteristics. Herein, the review includes the five types of variables that influence the aging process. The methodologies are subsequently highlighted along with their advantages and disadvantages. Furthermore, photography, optical, microscopy and electrochemical methods, and vibrational spectroscopy and mass spectrometry (MS) techniques are summarized in detail, with an emphasis on their utilization.

Age determination of common bottlenose dolphins (Tursiops truncatus) using dental radiography pulp:tooth area ratio measurements.

Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.

Hand Bone Age Radiography: Comparison Between Slot-scanning and Conventional Techniques

Background: Determination and longitudinal monitoring of progressive skeletal maturity are essential in the management of children with scoliosis. Although different methods for determining skeletal maturity exists, the most widely practiced method relies on the ossification pattern of the bones of the hand and wrist, which is traditionally acquired using conventional techniques and after the acquisition of the spine using the low-dose slot-scanning technique. Whereas the existing published literature has published promising results on the use of the slot-scanning technique to acquire these hand and wrist radiographs, image quality and radiation dose have not been systematically compared between these techniques. Thus, the objective of our study is to compare image quality, interpretation reliability, and radiation dose of hand bone age radiographs between slot-scanning and conventional techniques using age- and sex-matched children. Methods: This retrospective study included children who underwent hand radiographs using slot-scanning between October 1, 2019 and December 31, 2019; and matched children who underwent conventional radiography. Blinded to technique, 5 readers reviewed all radiographs after randomization to rate image quality and to determine bone age using the Greulich and Pyle classification. Dose area product was recorded. Mann-Whitney and t tests were used to compare variables between techniques and intraclass correlation (ICC) to determine observer agreement. Results: Our study cohort of 194 children (128 girls, 66 boys; mean age: 13.7±2.3 y) included 97 slot-scanning and 97 conventional radiographs. One (1%) slot-scanning and no conventional radiograph was rated poor in image quality. There was almost perfect interpretation reliability with slot-scanning with high interobserver (ICC=0.948) and intraobserver (ICC=0.996) agreements, comparable with conventional radiographs (ICCs=0.919 and 0.996, respectively). Dose area product (n=158) was lower (P<0.002) with slot-scanning than with conventional techniques. Conclusion: Almost perfect interobserver reliability and intraobserver reproducibility with slot-scanning radiographs (performed using significantly lower radiation doses) suggest that this technique for hand bone age determination can be a reliable adjunct to scoliosis monitoring. Level of Evidence: Level III.

Age and growth of three marine sculpins, Myoxocephalus jaok, Enophrys diceraus, and Gymnocanthus herzensteini, and age composition of fishery-bycatch sculpins in the western coastal Pacific around Hokkaido Island, Japan

The present study established an age determination technique and analyzed growth patterns in three sculpins, Myoxocephalus jaok, Enophrys diceraus, and Gymnocanthus herzensteini, which are major components of demersal fish assemblages in the subarctic Pacific. In all three species, only two or three otolith opaque zones were detected by surface observations, but numerous opaque zones were observed on otolith thin sections. For all species, the results of the study suggest that otolith opaque zones were formed annually. Although opaque zones were probably formed during summer for M. jaok and G. herzensteini, the timing could not be clarified for E. diceraus. The standard lengths at the same ages were greatest in M. jaok, moderate in G. herzensteini, and smallest in E. diceraus. In M. jaok and G. herzensteini, Bertalanffy growth curves were estimated for each sex, and were found to differ significantly between sexes. The bycatch of M. jaok and G. herzensteini in the western coastal Pacific around Hokkaido consisted mainly of young individuals, while that of E. diceraus was primarily older individuals. The results of this study may facilitate an understanding of the biological characteristics of sculpins not only around Hokkaido, but throughout the subarctic Pacific.

Growth of the brittle star Ophiura sarsii sarsii in Funka Bay, Hokkaido, Japan

The brittle star Ophiura sarsii with a disc diameter (DD) of less than 9 mm is an important prey item for flathead flounder Hippoglossoides dubius in Funka Bay. To establish an age-determination technique and estimate the growth equation for Ophiura sarsii sarsii (a dominant sub-species of O. sarsii in Funka Bay), we observed ridges on the surface of the arm ossicles. Specimens were collected using a sledge net, their DD measured, and the first arm ossicles examined from scanning electron microscopy images. Because the outermost ridges were formed from November to March, ridges were identified as yearly rings (annuli). The maximum age was 16.83 years (16.46-mm DD), and the largest sized individual was 22.19-mm DD (13.75 years). The best growth equation between DD and age (t) was given by Richard’s model using a minimum Akaike’s information criterion and growth rate comparison: DDt= 24.02 × {1 − 1.70 × exp[− 0.067 × (t + 8.25)]}−1/(−1.70). Small-sized (< 9-mm DD) and large-sized (ca. 15-mm DD) cohorts were composed of multi-year classes, and estimated growth rates from cohort progressions were 2.25 mm/year and 0.98 mm/year, respectively. We presumed that the large-sized cohort could be explained by a high survival rate and slow growth rate after the age of 5 or 6 years.

Star-planet tidal interaction and the limits of gyrochronology

Context. Age estimation techniques such as gyrochronology and magnetochronology cannot be applied to stars that have exchanged angular momentum with their close environments. This is especially true for a massive close-in planetary companion (with a period of a few days or less) that could have been strongly impacted by the rotational evolution of the host star, throughout the stellar evolution, through the star-planet tidal interaction. Aims. In this article, we provide the community with a reliable region in which empirical techniques such as gyrochronology can be used with confidence. Methods. We combined a stellar angular momentum evolution code with a planetary orbital evolution code to study in detail the impact of star-planet tidal interaction on the evolution of the surface rotation rate of the star. Results. We show that the interaction of a close-in massive planet with its host star can strongly modify the surface rotation rate of this latter, in most of the cases associated with a planetary engulfment. A modification of the surface rotation period of more than 90% can survive a few hundred Myr after the event and a modification of 10% can last for a few Gyr. In such cases, a gyrochronology analysis of the star would incorrectly make it appear as rejuvenated, thus preventing us from using this method with confidence. To try overcome this issue, we proposed the proof of concept of a new age determination technique that we call the tidal-chronology method, which is based on the observed pair Prot, ⋆–Porb of a given star-planet system, where Prot, ⋆ is the stellar surface rotational period and Porb the planetary orbital period. Conclusions. The gyrochronology technique can only be applied to isolated stars or star-planet systems outside a specific range of Prot, ⋆–Porb. This region tends to expand for increasing stellar and planetary mass. In that forbidden region, or if any planetary engulfment is suspected, gyrochronology should be used with extreme caution, while tidal-chronology could be considered. This technique does not provide a precise age for the system yet; however, it is already an extension of gyrochronology and could be helpful to determine a more precise range of possible ages for planetary systems composed of a star between 0.3 and 1.2 M⊙ and a planet more massive than 1 Mjup initially located at a few hundredths of au from the host star.

Monazite and xenotime U–Th–Pb $$_{\mathrm{total}}$$ total ages from basement rocks of the (central) Shillong–Meghalaya Gneissic Complex, Northeast India

Monazite and xenotime are the two most useful and commonly used geochronometers for deciphering ages from metamorphic rocks. The low analytical cost involved in electron probe micro-analyser chemical dating, ease of sample preparation and abundance in metamorphic rocks of wide P–T conditions make monazite and xenotime dating most widely used technique for age determination amongst metamorphic petrologists. This contribution presents age comparisons between coexisting monazite and xenotime in the basement metapelitic rocks of the central part of the Shillong–Meghalaya Gneissic Complex (SMGC). Thermobarometric estimates in the studied samples indicate granulite facies conditions of metamorphism with peak \({P{-}T}\) conditions of \(\sim \)6.5 kbar and \({\sim }750^\circ \hbox {C}\). Results indicate that xenotime in the basement rocks in the central SMGC formed in four discrete geological events while monazite either formed only in the latest Pan-African granulite grade metamorphic event or recrystallised during this event. Monazite in the studied samples yielded a single ubiquitous age of ca. 500 Ma. Xenotime in the study area, although found in only one sample, preserves four distinct ages at \(1153 \pm 29,930 \pm 36,823 \pm 41\; {\hbox {and}}\; 490 \pm 11\;\hbox {Ma}\). Preservation of Grenvillian ages in xenotime from central SMGC marks the eastward extension of Rodinia amalgamation front in the Indian Shield. The Neoproterozoic ages in xenotime from central SMGC suggest that the ca. 820 Ma high-grade metamorphism in the Eastern Indian Tectonic Zone had a wider impact in the SMGC than perceived previously.

Bone of contention: The applicability of the Greulich-Pyle method for skeletal age assessment in South Africa.

BackgroundThe Greulich–Pyle (GP) method is one of the most commonly used radiographic techniques for skeletal age (SA) determination. The applicability of this method for populations outside of the United States has been questioned and this has been investigated in several recent studies around the world. Only limited data are available on the accuracy of the GP method for a South African population.ObjectiveTo determine the accuracy and reliability of the GP method in a population from KwaZulu-Natal, South Africa.MethodA retrospective study was performed using a digital database consisting of 102 hand-wrist radiographs. The SA was estimated by two readers with different levels of experience, using the GP method. Differences between estimated SA and chronological age (CA) were analysed.ResultsSkeletal age determined with the GP method was found to significantly differ from CA. For the population as a whole, the GP method underestimated age. The greatest mean underestimation between SA and CA was 11.5 ± 17 months and 7.4 ± 13.2 months for the 10.1 to 15 year age groups in male and female patients, respectively. The method was found to have excellent inter- and intra-observer reliability.ConclusionThe GP method generally significantly underestimates age for both genders. Overestimation is also possible with individuals as young as 16 years old found by the method to be skeletally mature. Until new SA assessment tools are developed for South Africa, use of supplementary means of determination of SA should be considered, especially in medico-legal cases.

Dating of Archaeological Gold by Means of Solid State Electrochemistry

AbstractIn archaeology and history of art, age determination is a fundamental analytical problem. While several techniques for age determination of various materials, like radiocarbon dating, are established, these methods cannot be applied for metals, for which new techniques have to be developed. For the first time a dating method for archaeological gold objects is described which is based on a corrosion clock and electrochemical measurements, using the voltammetry of immobilized particles. Samples are prepared by ‘one touch’ with a graphite pencil, only transferring a few nanograms of the archaeological gold. The method has been calibrated with the help of a series of well‐documented gold specimen from different prehistory museums covering the last 2600 years. Our results prove that this corrosion clock is going on a constant pace, practically independent of the environment, making it most attractive for applications in archaeometry.

Micro-scale geochemical and crystallographic analysis of Buccinum undatum statoliths supports an annual periodicity of growth ring deposition

The whelk Buccinum undatum is commercially important in the North Atlantic. However, monitoring the ontogenetic age and growth of populations has been problematic for fisheries scientists owing to the lack of a robust age determination method. We confirmed the annual periodicity of growth rings present in calcified statoliths located in the foot of field-collected and laboratory reared whelks using microscale measurements of trace element geochemistry. Using Secondary Ion Mass Spectrometry (SIMS), annual trace element profiles were quantified at 2μm resolution in statoliths removed from whelks collected alive from three locations spanning the length of the UK; the Shetland Isles (North), the Menai Strait, North Wales (Mid) and Jersey (South). Clear cycles in the Mg/Ca ratio were apparent with minimum values corresponding with the visible dark statolith rings and comparatively higher ratios displayed in the first year of growth. Statoliths from one and two-year-old laboratory reared whelks of known age and life history contained one and two Mg/Ca cycles respectively and demonstrated that the statolith growth ring is formed during winter (February and March). Cycles of Na/Ca were found to be anti-correlated to Mg/Ca cycles, whilst ratios of Sr/Ca were inconsistent and showed an apparent ontogenetic increase, suggesting strong physiological control. Variability in elemental data will likely limit the usefulness of these structures as environmental recorders. The results obtained using SIMS for trace element analysis of statoliths confirms the robustness of the statolith rings in estimating whelk age. μXRD at 2μm spatial resolution demonstrated the statoliths were wholly aragonitic and thus trace element variation was not the result of possible differences in CaCO3 polymorph within the statolith. Changing XRD patterns along with SEM imaging also reveal an ‘hourglass’ microstructure within each statolith. The validation of the annual periodicity of statolith growth rings now provides a robust and novel age determination technique that will lead to improved management of B. undatum stocks.

Asteroid “one-sided” families: Identifying footprints of YORP effect and estimating the age

In a previous paper (Icarus 274, 314 (2016)) we have developed a new method to estimate the ages of asteroid families, based on an analysis of some expected consequence of the YORP effect acting on family members. The method is based on the identification of what we called the YORP eye, namely a region of depletion of the domain occupied by family members in the absolute magnitude - orbital semi-major axis plane. In this paper we develop a technique (“Mirroring tool”) to apply the same age determination method also in cases of strongly asymmetric families, for which it is difficult to assess the existence and location of a YORP eye. At the same time, we also apply some modifications to the procedure described in the previous paper. The results indicate that the mirroring tool can, in some cases, be satisfactorily effective, whereas in some other cases the results we obtain are more ambiguous. A necessary next step of this analysis will be to develop a better calibration of this method against the results obtained by means of other techniques, including primarily the age determination techniques based on analyses of the Yarkovsky-driven spreading in the semi-major axis of family members of different sizes.

The self‐secondary crater population of the Hokusai crater on Mercury

AbstractWhether or not self‐secondaries dominate small crater populations on continuous ejecta deposits and floors of fresh impact craters has long been a controversy. This issue potentially affects the age determination technique using crater statistics. Here the self‐secondary crater population on the continuous ejecta deposits of the Hokusai crater on Mercury is unambiguously recognized. Superposition relationships show that this population was emplaced after both the ballistic sedimentation of excavation flows and the subsequent veneering of impact melt, but it predated the settlement and solidification of melt pools on the crater floor. Fragments that formed self‐secondaries were launched via impact spallation with large angles. Complex craters on the Moon, Mercury, and Mars probably all have formed self‐secondaries populations. Dating young craters using crater statistics on their continuous ejecta deposits can be misleading. Impact melt pools are less affected by self‐secondaries. Overprint by subsequent crater populations with time reduces the predominance of self‐secondaries.

A novel approach for estimation of the natural mortality of the common whelk, Buccinum undatum (L.) and role of hermit crabs in its shell turnover

Analysis of simultaneously occurring live molluscs and empty shells of the whelk Buccinum undatum indicated similar abundance on the seabed making possible the estimation of recent natural mortality. Nearly all empty shells were occupied by hermit crabs Pagurus bernhardus and most of the remainder by Pagurus prideaux. P. bernhardus is highly selective for robust whelk shells, whereas anemone-protected P. prideaux use a range of smaller and thin-walled shells. Application of age size keys based on age reading of opercula surfaces permitted a tentative estimate of natural mortality of M=1.34 on trap fishing grounds for brown crab in the southwest North Sea (whelks aged 4–7 years) and M=0.85 and M=0.63 for the fishing grounds on the Western Waters (whelks aged 4-7 years and 4-9 years respectively). Estimates of total mortality (Z), based on size-frequencies of live whelks, were Z=1.35 (North Sea) and Z=1.46 and 1.23 (Western Waters, aged 4-7 years and 4-9 years). Estimates of M for the North Sea might be biased by differences in trap selectivity between hermit crabs and live whelks. This is a novel approach that might be developed for whelk fisheries assessment and management, particularly using better age determination techniques.

Using a Novel Absolute Ontogenetic Age Determination Technique to Calculate the Timing of Tooth Eruption in the Saber-Toothed Cat, Smilodon fatalis.

Despite the superb fossil record of the saber-toothed cat, Smilodon fatalis, ontogenetic age determination for this and other ancient species remains a challenge. The present study utilizes a new technique, a combination of data from stable oxygen isotope analyses and micro-computed tomography, to establish the eruption rate for the permanent upper canines in Smilodon fatalis. The results imply an eruption rate of 6.0 millimeters per month, which is similar to a previously published average enamel growth rate of the S. fatalis upper canines (5.8 millimeters per month). Utilizing the upper canine growth rate, the upper canine eruption rate, and a previously published tooth replacement sequence, this study calculates absolute ontogenetic age ranges of tooth development and eruption in S. fatalis. The timing of tooth eruption is compared between S. fatalis and several extant conical-toothed felids, such as the African lion (Panthera leo). Results suggest that the permanent dentition of S. fatalis, except for the upper canines, was fully erupted by 14 to 22 months, and that the upper canines finished erupting at about 34 to 41 months. Based on these developmental age calculations, S. fatalis individuals less than 4 to 7 months of age were not typically preserved at Rancho La Brea. On the whole, S. fatalis appears to have had delayed dental development compared to dental development in similar-sized extant felids. This technique for absolute ontogenetic age determination can be replicated in other ancient species, including non-saber-toothed taxa, as long as the timing of growth initiation and growth rate can be determined for a specific feature, such as a tooth, and that growth period overlaps with the development of the other features under investigation.