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In Nederland is de ringslang (Natrix helvetica) inheems. Op enkele locaties in Nederland is de oostelijke ringslang (Natrix natrix) echter geïntroduceerd, waaronder in Zuid-Limburg. De exotische oostelijke ringslang handhaaft zich in Nederland en hybridiseert met de inheemse ringslang. Een onwenselijke situatie, omdat het de overlevingskansen van de inheemse ringslang negatief kan beïnvloeden.

Amfibieën nemen wereldwijd af door verschillende ziektes, waarbij schimmels een grote rol spelen. Door onderzoek leren we steeds meer over de complexe interacties tussen de vaak invasieve schimmels, de amfibieën en hun omgeving. RAVON leidt de komende jaren gericht onderzoek om concrete beheer- en beleidsmaatregelen op te stellen tegen amfibieënschimmels.

Leidse biologiestudenten hebben de herkomst van exotische Alpenwatersalamanders bepaald. Een speciale DNA-techniek toont aan dat deze dieren uit verschillende uithoeken van Europa afkomstig zijn. Sterker nog: het gaat waarschijnlijk om verschillende soorten. Deze salamanders zijn waarschijnlijk uitgezet door mensen – en dat kan schadelijke gevolgen hebben voor de natuur en de biodiversiteit.

De weinige vuursalamanders die ons land rijk is, werden rond 2010 getroffen door een dodelijke ziekte: een schimmel die geïntroduceerd werd vanuit Oost-Azië. Door gebrek aan resistentie stierven in korte tijd vele vuursalamanders en leek de soort te verdwijnen uit Nederland. Afgelopen jaren onderzocht een internationaal onderzoeksteam hoe de vuursalamander er nu voor staat in Nederland en België.

In het noordwesten van Overijssel komt de ringslang in relatief grote populaties voor. In de regio Salland is de soort ook aanwezig, maar op afstand van deze grote kern en in kleinere deelpopulaties. Daardoor is de soort hier kwetsbaar. RAVON wil graag weten hoe het met de ringslang gaat en is daarom op zoek naar waarnemingen in Salland.

Develoment of image recognition AI algorithms for flower-visiting arthropods has the potential to revolutionize the way we monitor pollinators. Ecologists need light-weight models that can be deployed in a field setting and can classify with high accuracy. We tested the performance of three deep learning light-weight models, YOLOv5nano, YOLOv5small, and YOLOv7tiny, at object recognition and classification in real time on eight groups of flower-visiting arthropods using open-source image data. These eight groups contained four orders of insects that are known to perform the majority of pollination services in Europe (Hymenoptera, Diptera, Coleoptera, Lepidoptera) as well as other arthropod groups that can be seen on flowers but are not typically considered pollinators (e.g., spiders-Araneae). All three models had high accuracy, ranging from 93 to 97%. Intersection over union (IoU) depended on the relative area of the bounding box, and the models performed best when a single arthropod comprised a large portion of the image and worst when multiple small arthropods were together in a single image. The model could accurately distinguish flies in the family Syrphidae from the Hymenoptera that they are known to mimic. These results reveal the capability of existing YOLO models to contribute to pollination monitoring.

Almost 20 % of the global electricity consumption is caused by cooling systems. As the demand for cooling is expected to grow tenfold by 2050, improving the efficiency of cooling systems plays a critical role in addressing the global climate challenge. Passive Radiative Cooling (PRC) materials, which can dissipate heat into the surrounding as thermal radiation (especially through the atmospheric infrared window between 8 µm and 13 µm) have recently emerged. Hence, the project PaRaMetriC (Metrological Framework for Passive Radiative Cooling Technologies) aims to develop a comprehensive metrological framework with standardized performance indicators and testing protocols to enable comparable evaluation of their cooling performance on-site and the determination of potential energy savings that could derive from the deployment of such technologies. One work package within this project deals with the design of a testing setup and the development of a protocol for determining the figures of merit of candidate PRC materials by in-field measurements with a relative uncertainty below 10 %. For this purpose, on-site prototype setups are planned to be realized in different climatic regions, e.g. Barcelona (maritime Mediterranean climate), Madrid (continental Mediterranean climate), Torino (warm temperate climate) and Würzburg (moderate temperate climate), in order to cover a wide range of environmental conditions. With these prototype setups, measurements will be performed on candidate benchmark materials. Additionally, the environmental and atmospheric conditions (temperature, solar irradiance, humidity, wind speed, etc.) will be monitored during the measurements using appropriate sensors. Up to now, the design work has been started. This presentation gives an overview of the PaRaMetriC project and provides an outlook on the aimed future activities regarding the setup for in-field measurements, including the configuration of the setup (thermal insulation, thermal load, etc.)

We introduce a novel simulation tool capable of calculating the energy yield of a PV system based on its fundamental material properties and using self-consistent models. Thus, our simulation model can operate without measurements of a PV device. It combines wave and ray optics and a dedicated semiconductor simulation to model the optoelectronic PV device properties resulting in the IV-curve. The system surroundings are described via spectrally resolved ray tracing resulting in a cell resolved irradiance distribution, and via the fluid dynamics-based thermal model, in the individual cell temperatures. A lumped-element model is used to calculate the IV-curves of each solar cell for every hour of the year. These are combined factoring in the interconnection to obtain the PV module IV-curves, which connect to the inverter for calculating the AC energy yield. In our case study, we compare two types of 2 terminal perovskite/silicon tandem modules with STC PV module efficiencies of 27.7% and 28.6% with a reference c-Si module with STC PV module efficiency of 20.9%. In four different climates, we show that tandem PV modules operate at 1–1.9 °C lower yearly irradiance weighted average temperatures compared to c-Si. We find that the effect of current mismatch is significantly overestimated in pure optical studies, as they do not account for fill factor gains. The specific yields in kWh/kWp of the tandem PV systems are between −2.7% and +0.4% compared to the reference c-Si system in all four simulated climates. Thus, we find that the lab performance of the simulated tandem PV system translates from the laboratory to outdoors comparable to c-Si systems., Photovoltaic Materials and Devices, Energie and Industrie, Electrical Sustainable Energy

Research has examined tolerance of Muslim minority practices and anti-Muslim sentiments. We go beyond the existing research by applying latent profile analyses (LPA) on majority member’s evaluations of a range of Muslim practices and their feelings toward Muslims. We found five different subgroups of individuals among a sample of Dutch majority members (N = 831): a group that is positive towards Muslims and their practices (‘positive’), a group that is negative towards Muslims and their practices (‘negative’), a group that rejects all Muslim practices but reports positive feelings towards Muslims (‘intolerant’), a group that rejects only some practices and also has positive feelings towards Muslims (‘partly intolerant’), and a group that is not positive towards Muslims but accepts one practice (‘partly tolerant’). Furthermore, we show that these subgroups differ on key psychological variables (authoritarianism, status quo conservatism, and unconditional respect), and in their feelings towards other minority groups and (in)tolerance of other non-Muslim practices. We conclude that majority members can combine feelings toward Muslims and (in)tolerance of Muslim practices in different ways, and that the LPA approach makes an important contribution to the literature by providing a more nuanced understanding of how the public views Muslim minorities.