32 research outputs found

    Op zoek naar archeologie bij Doug's duin, Kamperhoekweg, Swifterbant, gemeente Dronten. Inventariserend veldonderzoek door middel van boringen

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    Grondsporen 4 presenteert de resultaten van het inventariserend veldonderzoek in de vorm van grondboringen uitgevoerd rondom een rivierduin ten oosten van de Kamperhoekweg in Swifterbant, gemeente Dronten

    One-sided jet at milliarcsecond scales in LSI+61303

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    We present Very Long Baseline Interferometry (VLBI) observations of the high mass X-ray binary LSI+61303, carried out with the European VLBI Network (EVN). Over the 11 hour observing run, performed 10 days after a radio outburst, the radio source showed a constant flux density, which allowed sensitive imaging of the emission distribution. The structure in the map shows a clear extension to the southeast. Comparing our data with previous VLBI observations we interpret the extension as a collimated radio jet as found in several other X-ray binaries. Assuming that the structure is the result of an expansion that started at the onset of the outburst, we derive an apparent expansion velocity of 0.003 c, which, in the context of Doppler boosting, corresponds to an intrinsic velocity of at least 0.4 c for an ejection close to the line of sight. From the apparent velocity in all available epochs we are able to establish variations in the ejection angle which imply a precessing accretion disk. Finally we point out that LSI+61303, like SS433 and Cygnus X-1, shows evidence for an emission region almost orthogonal to the relativistic jet.Comment: 7 pages, 4 figures, LaTeX, uses aa.cls. Accepted for publication in A&

    Schokkerhaven-E170 (gemeente Noordoostpolder). Vondsten AWN-veldverkenningen 2002-2009 en ROB-opgraving 1988

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    Grondsporen 9 presenteert de vondsten van de diverse veldverkenningen en de opgraving (1988) van de locatie Schokkerhaven-E17

    Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum.

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    Parasitoid wasps have fascinating life cycles and play an important role in trophic networks, yet little is known about their genome content and function. Parasitoids that infect aphids are an important group with the potential for biological control. Their success depends on adapting to develop inside aphids and overcoming both host aphid defenses and their protective endosymbionts. We present the de novo genome assemblies, detailed annotation, and comparative analysis of two closely related parasitoid wasps that target pest aphids: Aphidius ervi and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae). The genomes are small (139 and 141 Mbp) and the most AT-rich reported thus far for any arthropod (GC content: 25.8 and 23.8%). This nucleotide bias is accompanied by skewed codon usage and is stronger in genes with adult-biased expression. AT-richness may be the consequence of reduced genome size, a near absence of DNA methylation, and energy efficiency. We identify missing desaturase genes, whose absence may underlie mimicry in the cuticular hydrocarbon profile of L. fabarum. We highlight key gene groups including those underlying venom composition, chemosensory perception, and sex determination, as well as potential losses in immune pathway genes. These findings are of fundamental interest for insect evolution and biological control applications. They provide a strong foundation for further functional studies into coevolution between parasitoids and their hosts. Both genomes are available at https://bipaa.genouest.org
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