n the James Webb Space Telescope and Extremely Large Telescopes era we expect to characterize a number of potentially habitable Earth-like exoplanets. However, the characterization of these worlds... Show moren the James Webb Space Telescope and Extremely Large Telescopes era we expect to characterize a number of potentially habitable Earth-like exoplanets. However, the characterization of these worlds depends crucially on the accuracy of theoretical models. Validating these models against observations of planets with known properties will be key for the future characterization of terrestrial exoplanets. Due to its sensitivity to the micro- and macro-physical properties of an atmosphere, spectropolarimetry will be an important tool that in tandem with traditional flux-only observations will enhance the capabilities of characterizing Earth-like planets. In this presentation we benchmark two separate polarization-enabled radiative transfer codes against each other and against unique linear spectropolarimetric observations of the Earthshine (i.e., sunlight scattered by the dayside of the Earth and reflected back to the planet by the nightside of the Moon) that cover wavelengths from ~ 0.4 μm to ~ 2.3 μm. We find that the results from the two codes agree with each other but both underestimate the level of polarization of the Earthshine. We discuss how we plan to update the two codes to better fit the observations. We also report an interesting discrepancy between our models and the observed 1.27 μm O2 feature in the Earthshine, together with an analysis of potential methods for matching this feature and a discussion on the implications this has for future observations of habitable exoplanets. Show less
Studies into the history of mate search show that important mate choice criteria vary through time, influenced by societal circumstances, whereas others seem to remain constant. Nowadays, online... Show moreStudies into the history of mate search show that important mate choice criteria vary through time, influenced by societal circumstances, whereas others seem to remain constant. Nowadays, online dating has become one of the most popularways to meet a partner, which changed the mate selection process because this computer-mediated communication facilitates selective self-presentation. Biographies of dating app profiles are space limited and often selfwritten, providing insight in what users find crucial to mention about themselves and their wishes for a future partner. Here we collected 300 biographies from three online dating platforms and coded them on four content themes: dating intention, personality and appearance of self vs. potential partner, and lifestyle.We present a preliminary comparison of these mate choice criteria between gender and age. Show less
Schaik, L. van; Fontijn, D.; Schats, R.; Kootker, L. 2022
IntroductionOsteoarthritis (OA) is a common disease that degrades the cartilage in synovial joints, eventually leading to the direct destruction of bone. Today, OA is often observed in the hands... Show moreIntroductionOsteoarthritis (OA) is a common disease that degrades the cartilage in synovial joints, eventually leading to the direct destruction of bone. Today, OA is often observed in the hands and wrists, yet there have been few dedicated studies in past populations. This research aims to investigate how the living environment impacts the occurrence and patterning of hand and wrist OA in the medieval Netherlands.Materials & MethodsThe skeletal remains of 226 adult individuals from three sites (urban Alkmaar, rural Klaaskinderkerke, and urban hospital Kampen) were analysed to shed light on past prevalence and variation in affected joints between contextually different populations. The operational definition from Waldron (2009) was used to diagnose OA. ResultsExpectedly, a significant relationship between age and OA prevalence was found, χ2(2, N=226)=26.72, p<.001), with older individuals being more affected. Sex did not influence OA prevalence, χ2(2, N=226)=.75, p=0.68). Interestingly, even though the age distribution between the sites was similar, a clear interpopulation difference in overall hand and wrist OA prevalence was observed: hospital (32%), urban (12%) and rural (5%). Joint-specific patterning also showed variation between the sites, with OA predominance in the lateral wrist (thumb-base/wrist joint complex) in the urban hospital population, and in the medial wrist (piso-triquetral) in the urban population. ConclusionsThese results suggest that population context plays a significant role in OA occurrence. Differences in OA prevalence and patterning may suggest different activities or risk factors depending on the environment, which need to be explored further and on a larger scale. Show less
Umhlatuzana is an important archaeological site for the study of the Middle and Pleistocene Later Stone Age in South Africa with a largely continuous occupation sequence spanning MIS 4-2 (~70,000 -... Show moreUmhlatuzana is an important archaeological site for the study of the Middle and Pleistocene Later Stone Age in South Africa with a largely continuous occupation sequence spanning MIS 4-2 (~70,000 - 10,000 BP). The main technocomplexes represented are Still Bay, Howiesons Poort, Sibudan, final MSA and Robberg (from old to young). Changing selection of raw materials is an important issue in the study of the Middle-to-Later Stone Age transition that appears characterised by a shift in raw material use in addition to a technological organisation. Umhlatuzana was first excavated in 1975 by Jonathan Kaplan who suggested that the lithic assemblage of the Pleistocene deposits consisted mainly of quartz (61%), hornfels (37.6%), and quartzite (1.4%) (Kaplan 1990). Renewed excavations at the site were conducted during 2018 and 2019. This campaign aims to clarify the site’s formation processes employing micromorphological analysis and other techniques (Reidsma et al. 2021, Sifogeorgaki et al. 2020). Micromorphology uses thin sections of undisturbed sediment samples for microscopic studies. The sections allow a petrological inspection of rock fragments embedded in the deposits. Rather unexpectedly, the Umhlatuzana thin sections yield different raw material determinations than Kaplan (1990). While quartz and hornfels are present (around 23% and 25% respectively), they represent a much less sizable proportion than previously reported. Instead, the most prominent raw material observed is a quartz arenite sandstone (42%). Quartzite fragments were not detected.We therefore initiated an in-depth mineralogical and elemental classification of the raw materials. We distinguish 6 raw material types based on the thin section analysis: sandstone, quartz, hornfels, dolerite, chert and diorite. We then determined the elemental composition of the raw material types of the micromorphology samples using p-XRF. Additionally, p-XRF analysis was conducted on c. 100 specimens from the 2018-2019 excavation lithic collection. This allowed us to determine elemental characteristics of the raw materials used during the Pleistocene occupation of the site. Subsequently, p-XRF analysis was systematically performed on a larger sample set of lithics from the site in order to correctly determine their raw material type. The combination of micromorphological and p-XRF analysis of the Umhlatuzana assemblages demonstrates that if only visual inspection is done, the variability of raw materials used may be misinterpreted and the relative frequency of different rock types in an assembly may be over- or underestimated. Future work will aim at re-visiting the raw material categorization of artefacts excavated during the 1975 excavations. Show less
The discourse of Islam’s relation to evolution has been steadily developing over the past few decades. Still, the field is lacking sufficient academic maturity. There are critical intradisciplinary... Show moreThe discourse of Islam’s relation to evolution has been steadily developing over the past few decades. Still, the field is lacking sufficient academic maturity. There are critical intradisciplinary, interdisciplinary, and multidisciplinary perspectives that need attention in this complex conversation. To help fill this lacuna, this online conference aims to widen the number of Islamic perspectives on the matter, and further the resolution on issues that stimulate Muslim thinkers with evolution. The following are the themes of interest for this conference. The conference will address key themes in Science and Religion, Evolutionary Biology, and Islamic theology and philosophy. Show less
Umhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits... Show moreUmhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits bearing Pleistocene archaeological assemblages at Umhlatuzana rockshelter appear homogeneous with no macroscopically visible stratigraphic boundaries. This means the integrity of the archaeological assemblages is difficult to ascertain. Moreover, the sedimentation rate, taphonomic history, and the environmental context across the sequence are unclear. This study aims to resolve these issues by integrating different geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analysed for pH, elemental composition (XRF), and Magnetic Susceptibility. These methods were chosen because they provide insight into ‘invisible’ geoarchaeological dynamics, related to sediment input (geogenic and anthropogenic), taphonomy, and environmental conditions. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. Furthermore, the gradual change within the geochemical data indicates that no large-scale sediment mixing took place (contrary to previous suggestions), while small-scale mixing related to bioturbation is visible in the micromorphological thin sections. Our study offers a successful multi-proxy approach to systematically sample and analyse archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and postdepositional history of the site, and allows questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed. Show less
Cribra orbitalia, orbital roof porosity, is one of the most frequently scored skeletal lesions in archaeological remains from the Netherlands. Cribra orbitalia is generally associated with... Show moreCribra orbitalia, orbital roof porosity, is one of the most frequently scored skeletal lesions in archaeological remains from the Netherlands. Cribra orbitalia is generally associated with childhood anaemia, but the underlying cause of this red blood cell disorder is still debated. Gowland and Westen (2012) showed a clear correlation between cribra orbitalia prevalence and certain geographic areas in the UK, linking this to malaria. As the Netherlands was plagued by malaria as well, this parasitic infection may have been an important contributing factor to the prevalence of anaemia in the medieval period. To contribute to this complex debate on the aetiology, and to study the hypothesis of malaria as an important causative agent, this research investigates the spatial distribution of cribra orbitalia in the medieval Netherlands. In total, 1629 individuals from 19 different medieval sites have been studied for the presence or absence of cribra orbitalia and severity of the lesions (1 to 3, Stuart-Macadam 1985). Results show a greater prevalence of cribra orbitalia in the areas deemed malarial based on palaeogeographic and 20th century malaria distribution data (10.9% vs. 23.1%, p<0.001). Yet, even though the mean scores are slightly higher in the malarial area, the severity of the lesions does not significantly vary. This study suggests that malaria may have been an important contributing factor to the prevalence of cribra orbitalia and that it was likely an influential disease in the low-lying coastal areas of the Netherlands with a substantial impact on health and life expectancy. Show less
