2,572 research outputs found
A genome-wide investigation of the worldwide invader Sargassum muticum shows high success albeit (almost) no genetic diversity
Twenty years of genetic studies of marine invaders have shown that successful invaders are often characterized by native and introduced populations displaying similar levels of genetic diversity. This pattern is presumably due to high propagule pressure and repeated introductions. The opposite pattern is reported in this study of the brown seaweed, Sargassum muticum, an emblematic species for circumglobal invasions. Albeit demonstrating polymorphism in the native range, microsatellites failed to detect any genetic variation over 1,269 individuals sampled from 46 locations over the Pacific-Atlantic introduction range. Single-nucleotide polymorphisms (SNPs) obtained from ddRAD sequencing revealed some genetic variation, but confirmed severe founder events in both the Pacific and Atlantic introduction ranges. Our study thus exemplifies the need for extreme caution in interpreting neutral genetic diversity as a proxy for invasive potential. Our results confirm a previously hypothesized transoceanic secondary introduction from NE Pacific to Europe. However, the SNP panel unexpectedly revealed two additional distinct genetic origins of introductions. Also, conversely to scenarios based on historical records, southern rather than northern NE Pacific populations could have seeded most of the European populations. Finally, the most recently introduced populations showed the lowest selfing rates, suggesting higher levels of recombination might be beneficial at the early stage of the introduction process (i.e., facilitating evolutionary novelties), whereas uniparental reproduction might be favored later in sustainably established populations (i.e., sustaining local adaptation).Agence Nationale de la Recherche - ANR-10-BTBR-04; European Regional Development Fund; Fundacao para a Ciencia e a Tecnologia - SFRH/BPD/107878/2015, UID/Multi/04326/2016, UID/Multi/04326/2019; Brittany Region;info:eu-repo/semantics/publishedVersio
De zaadteelt van ui (Allium cepa) - Handleiding voor zaadteelt en selectie
Deze handleiding is met name bedoeld voor telers die met zaadteelt en/of selectie aan de gang willen gaan onder Nederlandse klimaatomstandigheden. Deze handleiding is gebaseerd op veel praktische ervaring uit het veld, deels ervaring vanuit (oude)vakliteratuur, en deels door interviews met ervaren zaadtelers en selecteurs
The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements
This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total column CO2. The participating transport models IFS, LMDZ, TM3, and TM5 were run in forward and inverse mode using common a priori CO2 fluxes and initial concentrations. Forward simulations of column averaged CO2 (xCO2) mixing ratios vary between the models by s=0.5 ppm over the continents and s=0.27 ppm over the oceans. Despite the fact that the models agree on average on the sub-ppm level, these modest differences nevertheless lead to significant discrepancies in the inverted fluxes of 0.1 PgC/yr per 106 km2 over land and 0.03 PgC/yr per 106 km2 over the ocean. These transport model induced flux uncertainties exceed the target requirement that was formulated for the A-SCOPE mission of 0.02 PgC/yr per 106 km2, and could also limit the overall performance of other CO2 missions such as GOSAT. A variable, but overall encouraging agreement is found in comparison with FTS measurements at Park Falls, Darwin, Spitsbergen, and Bremen, although systematic differences are found exceeding the 0.5 ppm level. Because of this, our estimate of the impact of transport model uncerainty is likely to be conservative. It is concluded that to make use of the remote sensing technique for quantifying the sources and sinks of CO2 not only requires highly accurate satellite instruments, but also puts stringent requirements on the performance of atmospheric transport models. Improving the accuracy of these models should receive high priority, which calls for a closer collaboration between experts in atmospheric dynamics and tracer transpor
Minimizing gravitational lensing contributions to the primordial bispectrum covariance
The next generation of ground-based cosmic microwave background (CMB) experiments aim to measure temperature and polarization fluctuations up to ℓmax≈5000 over half of the sky. Combined with Planck data on large scales, this will provide improved constraints on primordial non-Gaussianity. However, the impressive resolution of these experiments will come at a price. Besides signal confusion from galactic foregrounds, extragalactic foregrounds, and late-time gravitational effects, gravitational lensing will introduce large non-Gaussianity that can become the leading contribution to the bispectrum covariance through the connected four-point function. Here, we compute this effect analytically for the first time on the full sky for both temperature and polarization. We compare our analytical results with those obtained directly from map-based simulations of the CMB sky for several levels of instrumental noise. Of the standard shapes considered in the literature, the local shape is most affected, resulting in a 35% increase of the estimator standard deviation for an experiment such as the Simons Observatory (SO) and a 110% increase for a cosmic-variance limited experiment, including both temperature and polarization modes up to ℓmax=3800. Because of the nature of the lensing four-point function, the impact on other shapes is reduced while still non-negligible for the orthogonal shape. Two possible avenues to reduce the non-Gaussian contribution to the covariance are proposed: First by marginalizing over lensing contributions, such as the Integrated Sachs Wolfe (ISW)-lensing three-point function in temperature, and second by delensing the CMB. We show the latter method can remove almost all extra covariance, reducing the effect to below <5% for local bispectra. At the same time, delensing would remove signal biases from secondaries induced by lensing, such as ISW lensing. We aim to apply both techniques directly to the forthcoming SO data when searching for primordial non-Gaussianity
Design of a robotic system for battery dismantling from tablets
Due to the rapid increase in sales of mobile electronic devices, the number of batteries ending up in waste electric and electronic equipment (WEEE) is also rapidly increasing. According to the EU legislation, all batteries need to be removed from WEEE, which is currently done manually for tablets, posing potential safety risks for workers and resulting in high processing costs due to the labour intensity of the required dismantling operations. Therefore, a robotic dismantling system is developed in this research to automatically remove both the back covers and batteries from a mixed waste stream of tablets of different models and brands. At the outset of the design process, a total of 47 randomly collected tablets were analyzed to define the location of the battery and the required manual dismantling time. Thereafter, a robotic bending method was tested for removing the back cover. Once the battery is exposed, two different methods are tested: using a heat gun to loosen the glue that fixes the battery to the rest of the tablet and a robotic scraping method with a spatula to mechanically extract the battery. Whereas the required time for only the heating showed to be more than 120s, the results with the bending and scraping tool show that the proposed robotic dismantling system is capable of removing the back cover and battery for 63% of the tested tablets in less than 90s. However, to increase the economic viability and robustness of the proposed method to be able to cope with the high variety in tablet model designs, future work is required to develop algorithms to recognize product models to enable to define and retrieve product specific toolpaths for dismantling.Peer ReviewedPostprint (published version
An inventory of psychosocial oncological interventions in The Netherlands:identifying availability, gaps, and overlap in care provision
Purpose: While a wide range of psychosocial oncological (PO) interventions has been developed, a systematic overview of interventions to inform patients, care providers, as well as researchers, policy makers and health insurers, is lacking. The aims of this paper were (1) to describe the attainment of this overview, which may be used in other jurisdictions and for other health conditions and (2) to reflect on what determines developments in this field. Methods: Dutch researchers and care providers were invited to describe PO-interventions they apply in research or clinical practice. Selection criteria for what constituted a PO-intervention were determined. The input was organized in 12 predefined categories (e.g. physical functioning, genetics). Findings: Sixty-six PO-interventions were included in the overview. Two major categories were psychosocial functioning (24%) and physical functioning and recovery (24%). Interventions are mostly directed at adults (65%) and not aimed at a specific type of cancer (61%). Nearly 25% of the interventions lacked scientific underpinning. Conclusions: This paper provides an overview of Dutch PO-interventions and input on what drives their development. The categorizing method can be used in other jurisdictions and for other health care conditions. A next step would be to investigate the effectiveness and evidence of PO-interventions. Implications for Psychosocial Providers and Policy: The open access overview of interventions provides referral information for care providers. By identifying possible gaps and overlap, the overview looks at possible drivers behind developments in this field which will be of interest to policy makers
- …