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Inbreeding depression affects the growth of seedlings of an African timber species with a mixed mating reproductive system, Pericopsis elata (Harms) Meeuwen
Get PDFTracing the geographic origin of invasive pests using derived SNPs based on whole genome resequencing data: an example of <i>Bactrocera dorsalis</i>
No full textSpanish polychromed sculpture in the Low Countries : a journey through art history and techniques
No full textDriven Collisionless Reconnection of Force-free Flux Tubes: From Onset to Coalescence
No full textWe investigate the onset of driven collisionless reconnection and plasmoid formation in a magnetically dominated pair plasma, using 2D particle-in-cell simulations. Two force-free flux tubes of radius R are initially pushed together with a prescribed velocity, forming a current sheet whose width shrinks until reconnection sets in. Even in our largest simulation with R ≈ 1600 plasma skin depths, the sheet thickness at reconnection onset is comparable to the skin depth. Plasmoid chains develop when the sheet length-to-width aspect ratio A ≳ 30. In the strongly magnetized limit, the onset of reconnection occurs in roughly 2–6 light-crossing times, depending on the imposed driving timescale, which controls the duration of the thinning phase. In the subsequent nonlinear merging phase, the evolution becomes effectively independent of the initially imposed velocity, leading to magnetic-energy dissipation consistent with a normalized reconnection rate ∼0.1. Our results have important implications for explosive release of magnetic energy in magnetospheres of astrophysical compact objects and their surroundings
Inventaire des archives de la commune de Hamipré : Dépôt 2009 ((1812) 1821-1976 (1979))
No full textDe la Révolution française à la fusion des communes de 1977, Hamipré traverse deux siècles de recompositions administratives qui sculptent son identité. Tour à tour autonome, rattachée, puis rétablie, la commune évolue au rythme des réformes, des réalités rurales et des bouleversements politiques; jusqu’aux combats d’août 1914. Cet inventaire révèle, à travers les délibérations, finances, registres de population, travaux publics, enseignement ou bienfaisance, la manière dont une petite communauté gère son territoire, ses habitants et ses ressources. Une plongée précise, sans détours, dans la mémoire administrative d’un village ardennais en constante transformation.The records described in this inventory are held at the State Archives in Arlon (inventory code 521 - AEA 476).This inventory is the fixed published version dated 13-02-2025. For the dynamic inventory under active revision, including recent updates and additions, please consult our online search platform AGATHA. In AGATHA, you can also request the archival items you wish to consult in the reading room
Harmonisation of sixteen tropospheric ozone satellite data records
No full textThe first Tropospheric Ozone Assessment Report (TOAR, 2014–2019) encountered several observational challenges that limited the confidence in estimates of the burden, short-term variability, and long-term changes of ozone in the free troposphere. One of these challenges is the difficulty to interpret the consistency of satellite measurements obtained with different techniques from multiple sensors, leading to differences in spatiotemporal sampling, vertical smoothing, a-priori information, and uncertainty characterisation. This motivated the Committee on Earth Observation Satellites (CEOS) to initiate a coordinated activity VC-20-01 on improving the assessment and harmonisation of tropospheric ozone measured from space. Here, we report on work that contributes to this CEOS activity, as well as to the ongoing second TOAR assessment (TOAR-II, 2020–2025). Our objective is to harmonise the spatiotemporal perspective of (sixteen) satellite ozone data records, thereby accounting as much as possible for differences in vertical smoothing and sampling. Four harmonisation methods are presented to achieve this goal: two for ozone profiles obtained from nadir sounders (UV-visible, IR, and combined UV-IR), and two for tropospheric ozone column products derived by one of the residual methods (Convective Cloud Differential or Limb–Nadir Matching). We discuss to what extent harmonisation may affect assessments of the spatial distribution, seasonal cycle, and long-term changes in free tropospheric ozone, and we anchor the harmonised profile data to ozonesonde measurements recently homogenised as part of TOAR-II. We find that approaches that use global ozone fields as a transfer standard (here the Copernicus Atmosphere Monitoring Service ReAnalysis, CAMSRA) to constrain the harmonisation generally lead to the largest reduction of the inter-product dispersion (IPD) between satellite datasets. These harmonisation efforts, however, only partially account for the observed discrepancies between the satellite datasets, with a reduction of about 10 %–40 % of the IPD upon harmonisation, depending on the products involved and with strong spatiotemporal dependences. This work therefore provides evidence that it is not only the differences in spatiotemporal smoothing and sampling, but rather the differences in measurement uncertainty that pose the main challenge to the assessment of the spatial distribution and temporal evolution of free tropospheric ozone from satellite observations
Synthetic spectra of the aurora: N2, N2+, N, N+, O2+ and O emissions
No full textStudying the auroral emissions is of great importance since they are created in an atmospheric layer (80–300 km) where in-situ measurements are complicated and they represent a good proxy of the particle precipitations into the atmosphere. The emission spectrum of the aurora is complex, made of both atomic and molecular lines. The intensities of these emissions vary with the solar and geomagnetic activities, mostly due to the particle precipitations. In this paper, we simulate auroral emission spectra for a given distribution of precipitating electrons using Transsolo, a kinetic code solving the transport equation of the electrons along the local magnetic field line. It allows calculations of the particle fluxes for different energies, pitch-angles and altitudes, from which the related emissions are computed. The modules to compute the emissions have recently been updated by including the vibrational structures of the molecular bands and several atomic lines. Only the O2 emissions and the hydrogen emissions due to proton precipitations are not considered in the model. The code also permits to relate auroral spectra with characteristics of the precipitating electrons such as their mean energy and total fluxes at the top of the atmosphere. Such simulations also provide the auroral spectrum at any altitude of the upper atmosphere, which is important in the perspective of volume emission reconstructions as done using tomographic-like techniques. Moreover, many auroral monitoring instruments are equipped with filters of variable widths. Such synthetic spectra can help to identify possible contamination of the measurements due to overlap of several emission lines. For example, the green line at 557.7 nm overlaps with several O2+, N I and N2 lines or bands in a ±5 nm range. Calculating the relative ratio of these lines in different conditions is therefore crucial for measurements using a filter of 5 nm width. For example, we discuss if these overlapped lines could possibly be at the origin of the linear polarization measured in the green line despite the fact that the theory of impact polarization predicts zero polarization
De ontsluiting van archieven : Richtlijnen en aanbevelingen voor de ordening en beschrijving van archieven in het Rijksarchief
No full textDeze handleiding biedt een doordacht en praktisch kader voor iedereen die het archivistisch vakmanschap wil beheersen. Herman Coppens distilleert jarenlange ervaring binnen het Rijksarchief tot een heldere methode voor de ordening en beschrijving van archieven zodat archivarissen, onderzoekers en collectiebeheerders met vertrouwen kunnen navigeren door zelfs de meest weerbarstige archiefbestanden.
Dit boek gaat verder dan technische richtlijnen. Het toont hoe een goed ontsloten archief kennis stimuleert, onderzoek versnelt en verborgen verhalen zichtbaar maakt. Met concrete aanbevelingen, uitgewerkte principes en een sterke focus op toepasbaarheid is deze gids een solide metgezel voor zowel de beginnende als de doorgewinterde professional.Print edition available for purchase through the National Archives of Belgium. More information via publicat[at]arch.be
Overzicht nieuwe inventarissen en zoekinstrumenten Rijksarchief in België - Oktober 2025
No full textMonthly overview of new inventories and finding aids: October 2025
A Lagrangian-frame technique for investigating plasma turbulence in complex underlying system-scale structures
No full textWe present a method to visualize and analyze turbulence within macroscopic flows that feature complex structures not determined by the turbulence itself. We introduce a technique to shift to a Lagrangian frame that captures the macroscopic scales not part of the turbulent cascade. We then study turbulence within this frame that is comoving with the large-scale nonturbulent flow. The method is applied to Particle-in-Cell simulations of astrophysical plasma. Specifically, we use two cases to illustrate the new method. First, we consider a magnetic perturbation in the solar wind interacting with the bow shock, magnetosheath, and magnetopause in the dayside of the Earth. Second, we consider an Earthward flow generated by magnetic reconnection in the magnetotail. In these cases we show how the Lagrangian frame can be used to distinguish turbulent fluctuations from the macroscopic flow structures due to the evolution of the system caused by macroscopic forcing