Non-destructive dental-age calculation methods in adults: intra- and inter-observer effects

The aim of the present study was to obtain data on the reliability and reproducibility of two non-destructive dental-age estimation methods in adults by calculating inter- and intra-observer effects. Both a morphological and a radiological technique available in the scientific literature were evaluated on a number of recently extracted teeth: the morphological technique was evaluated on a total of 160 teeth by two examiners, while three examiners applied the radiological technique on apical radiographs of 72 extracted teeth. Paired t-tests were used to calculate intra- and inter-observer differences. For the morphological method, both examiners were able to produce dental-age estimations that did not differ significantly from the real age of the teeth, obtaining a mean error between 0.5 and 1.8 years and a standard deviation of this error between 9.0 and 11.3 years. When using the radiological technique according to the original protocol, all three examiners produced age estimations that were statistically comparable to the real age of the teeth with a mean error of 0.5-2.5 years and a standard deviation of 4.6-9.8 years. For both techniques, intra-observer differences were observed. Based on the results of this study, it can be concluded that both non-destructive dental-age estimation techniques were able to produce reasonably accurate dental-age estimations, at least when these techniques were applied appropriately. However, the forensic odontologist is recommended to use different age estimation techniques and perform repetitive measurements in order to verify the reproducibility of the calculations performed.     

Through thick and thin? The dynamics of government support across income groups during economic crises

Students of economic voting have recently made substantial progress in their understanding of when the economy is and is not likely to impact election outcomes. Our knowledge of the lower level dynamics that drive these aggregate results remains fairly murky. In this paper we test competing theoretical claims about how individual level orientations toward political economy lead to observed aggregate trends in support for incumbent politicians. We do this with models of support for the Labour Party in the United Kingdom before and during the recent global economic turndown.     

Countries start to explain how their climate contributions are fair: more rigour needed

In the lead-up to the Paris Agreement, every country was invited to submit an intended nationally determined contribution (INDC), and indicate how it is fair. We analyse how countries have explained the equity of mitigation and adaptation in 163 INDCs, providing a bottom-up analysis of equity to complement a literature that has focused on top-down allocations. While no single indicator of equity was used by all INDCs, a menu of quantified indicators or tiered approaches could provide bounded flexibility across different national circumstances. The most common equity indicator used in mitigation INDCs is the country’s ‘small share’ of global emissions, followed by per capita emissions. The emissions of individual ‘small share’ INDCs add up to 24% of annual global emissions when using a consistent data set. Per capita emissions are used across a range of countries with low (0.5) to high (25 t CO₂–eq per capita) values for that indicator. Adaptation is included in 89% of INDCs, of which more than half quantify impacts in some manner, and two-thirds use vulnerability as an equity argument. Broadly, we find that most claims to equity are either unsubstantiated or drawn from analysis by in-country experts. Only two INDCs refer to independent evidence, and none consider the consequences of their approach when applied to all countries. Given that the aggregate effect of INDCs will not be sufficient to keep global temperature increase well below 2 °C, and even less to keep temperature below a 1.5 °C rise, the INDCs have distributional implications. More rigorous information is needed to assess relative fair shares, which could be provided officially in future nationally determined contributions (NDCs). Absent improved information, it is likely that researchers and civil society will continue to assess informally what could be considered fair. A hybrid approach to equity—combining bottom-up assessment and top-down allocation—would be consistent with the hybrid architecture of the Paris Agreement, which comprises bottom-up elements such as NDCs and top-down elements such as global goals. Improved information on equity in NDCs will be an important input to the global stocktake ‘in the light of equity’.     

Age calculation using X-ray microfocus computed tomographical scanning of teeth: a pilot study

To correlate dental age with an individual's chronological age based on the calculated volume ratio of pulp versus tooth volume measured, an X-ray microfocus computed tomography unit (microCT) with 25 microm spatial resolution was used to non-destructively scan 43 extracted single root teeth of 25 individuals with well-known chronological age. Custom-made analysis software was used by two examiners to obtain numerical values for pulpal and tooth volume. The ratio of both was calculated and statistically processed. No significant intra- or inter-examiner differences were found. In fact, a very strong concordance correlation coefficient was found. Linear regression analysis showed a coefficient of determination (r) of 0.31 which suggests that there is a rather weak correlation between the volume ratio of pulp versus tooth and biological age. Although rather time consuming, this technique shows promising results for dental age estimation in a non-destructive manner using X-ray microfocus computed tomography.