The influence of motion artefacts on magnetic resonance imaging of the clavicles for age estimation

Purpose To determine how motion affects stage allocation to the clavicle's sternal end on MRI. Materials and methods Eighteen volunteers (9 females, 9 males) between 14 and 30 years old were prospectively scanned with 3-T MRI. One resting-state scan was followed by five intentional motion scans. Additionally, a control group of 72 resting-state scans were selected from previous research. Firstly, six observers allocated developmental stages to the clavicles independently. Secondly, they re-assessed the images, allocating developmental statuses (immature, mature). Finally, the resting-state scans of the 18 volunteers were assessed in consensus to decide on the "correct" stage/status. Results were compared between groups (control, prospective resting state, prospective motion), and between staging techniques (stages/statuses). Results Inter-observer agreement was low (Krippendorff alpha 0.23-0.67). The proportion of correctly allocated stages (64%) was lower than correctly allocated statuses (83%). Overall, intentional motion resulted in fewer assessable images and less images of sufficient evidential value. The proportion of correctly allocated stages did not differ between resting-state (64%) and motion scans (65%), while correctly allocated statuses were more prevalent in resting-state scans (83% versus 77%). Remarkably, motion scans did not render a systematically higher or lower stage/status, compared to the consensus. Conclusion Intentional motion impedes clavicle MRI for age estimation. Still, in case of obvious disturbances, the forensic expert will consider the MRI unsuitable as evidence. Thus, the development of the clavicle as such and the staging technique seem to play a more important role in allocating a faulty stage for age estimation

Dairying, diseases and the evolution of lactase persistence in Europe

Update notice Author Correction: Dairying, diseases and the evolution of lactase persistence in Europe (Nature, (2022), 608, 7922, (336-345), 10.1038/s41586-022-05010-7) Nature, Volume 609, Issue 7927, Pages E9, 15 September 2022In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years(1). Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions(2,3). Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectoriesthan uniform selection since the Neolithic period. In the UK Biobank(4,5) cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.Peer reviewe

Definitief archeologisch onderzoek (DAO) van de leidingsleuven en het wegtracé te Opperdoes-Kluiten-Zuid

Met lit. op

Optimal policy for a multi-location inventory system with a quick response warehouse

We study a multi-location inventory problem with a so-called quick response warehouse. In case of a stock-out at a local warehouse, the demand might be satis??ed by a stock transfer from the quick response warehouse. We derive the optimal policy for when to accept and when to reject such a demand at the quick response warehouse. We also derive conditions under which it is always optimal to accept these demands. Furthermore, we conduct a numerical study and consider model variations

Optimal lateral transshipment policy for a two location inventory problem

We consider an inventory model for spare parts with two stockpoints, providing repairable parts for a critical component of advanced technical systems. As downtime costs for these systems are huge, ready-for-use spare parts are kept on stock, to be able to quickly respond to a breakdown of a system. We allow for lateral transshipments of parts between the stockpoints upon a demand arrival for a spare part. We are interested in the optimal lateral transshipment policy. We consider a continuous review setting, where the initial number of spare parts at each location is given. We assume Poisson demand processes, and allow for asymmetric demand rates and asymmetric costs structures at the two locations. Defective parts are replaced, and returned to the stockpoint for repair. Each location has ample repair capacity, and repair times are exponentially distributed, with the same mean repair time for both locations. Demands are satisfied from own stock, via a lateral transshipment, or via an emergency procedure. Using dynamic programming, we completely characterize and prove the structure of the optimal lateral transshipment policy, that is, the policy for satisfying demands, minimizing the long-run average costs of the system. This optimal policy is a threshold type policy. In addition, we derive conditions under which the so-called hold back and complete pooling policies are optimal, which are both policies that are often assumed in the literature

A geophysical multi-method approach to investigate the archaeological landscape of Lanakerveld (NL)

– Large scale geophysical prospection of an archaeological landscape in the Netherland. – Integrated and multimethodological approach for archaeological interpretation. – Challenges for the prospecting and interpretation of multiperiod archaeological sites