Piloting access to the Belgian web-archive for scientific research: a methodological exploration

The web is fraught with contradiction. On the one hand, the web has become a central means of information in everyday life and therefore holds the primary sources of our history created by a large variety of people (Milligan, 2016; Winters, 2017). Yet, much less importance is attached to its preservation, meaning that potentially interesting sources for future (humanities) research are lost. Web archiving therefore is a direct result of the computational turn and has a role to play in knowledge production and dissemination as demonstrated by a number of publications (e.g. Brügger & Schroeder, 2017) and research initiatives related to the research use of web archives (e.g. https://resaw.eu/). However, conducting research, and answering research questions based on web archives - in short; ‘using web archives as a data resource for digital scholars’ (Vlassenroot et al., 2019) - demonstrates that this so-called ‘computational turn’ in humanities and social sciences (i.e. the increased incorporation of advanced computational research methods and large datasets into disciplines which have traditionally dealt with considerably more limited collections of evidence), indeed requires new skills and new software. In December 2016, a pilot web-archiving project called PROMISE (PReserving Online Multiple Information: towards a Belgian StratEgy) was funded. The aim of the project was to (i) identify current best practices in web-archiving and apply them to the Belgian context, (ii) pilot Belgian web-archiving, (iii) pilot access (and use) of the pilot Belgian web archive for scientific research, and (iv) make recommendations for a sustainable web-archiving service for Belgium. Now the project is moving towards its final stages, the project team is focusing on the third objective of the project, namely how pilot access to the Belgian web archive for scientific research. The aim of this presentation is to discuss how the PROMISE team approached piloting access to the Belgian web-archive for scientific research, including: a) reviewing how existing web-archives provide access to their collections for research, b) assessing the needs of researchers based on a range of initiatives focussing on research-use of web-archives (e.g. RESAW, BUDDAH, WARCnet, IIPC Research Working Group, etc. and c) exploring how the five persona’s created as part of the French National Library’s Corpus project (Moiraghi, 2018) could help us to explore how different types of academic researchers that might use web archives in their research. Finally, we will introduce the emerging Digital Research Lab at the Royal Library of Belgium (KBR) as part of a long-term collaboration with the Ghent Centre for Digital Humanities (GhentCDH) which aims to facilitate data-level access to KBR’s digitised and born-digital collections and could potentially provide the solution for offering research access to the Belgian web-archive

The low molecular weight fraction of compounds released from immature wheat pistils supports barley pollen embryogenesis

Pollen embryogenesis provides a useful means of generating haploid plants for plant breeding and basic research. Although it is well established that the efficacy of the process can be enhanced by the provision of immature pistils as a nurse tissue, the origin and compound class of the signal molecule(s) involved is still elusive. Here, a micro-culture system was established to enable the culturing of populations of barley pollen at a density too low to allow unaided embryogenesis to occur, and this was then exploited to assess the effect of using various parts of the pistil as nurse tissue. A five fold increase in the number of embryogenic calli formed was obtained by simply cutting the pistils in half. The effectiveness of the pistil-conditioned medium was transitory, since it needed replacement at least every four days to measurably ensure embryogenic development. The differential effect of various size classes of compounds present in the pistil-conditioned medium showed that the relevant molecule(s) was of molecular weight below 3 kDa. This work narrows down possible feeder molecules to lower molecular weight compounds and showed that the cellular origin of the active compound(s) is not specific to any tested part of the pistil. Furthermore the increased recovery of calli during treatment with cut pistils may provide a useful tool for plant breeders and researchers using haploid technology in barley and other plant species

Representative structural element approach for assessing the mechanical properties of automated fibre placement-induced defects

In this paper, a 3D finite element modelling approach is presented to assess the effects of manufacturing defects within composite structures. The mesoscale modelling approach derives the stress-strain response of a composite structure from a representative structural element. A set of tensile and bending loads is used to compute its ABD-Matrix. The boundary conditions of the model are described in detail as is the extraction of the strain and curvature response. The derived stiffness from the presented modelling approach is compared to the classical lamination theory and the models' shortcomings are discussed. Finally, the influence of a gap, an overlap and two different-sized fuzzballs on the macroscopic mechanical properties of a composite structure are evaluated using the presented multiscale modelling approach, thereby providing stiffness matrices influenced by the defects for the use in global models of composite parts

Effects of Arctic ozone on the stratospheric spring onset and its surface response

Ozone in the Arctic stratosphere is subject to large interannual variability, driven by both chemical ozone depletion and dynamical variability. Anomalies in Arctic stratospheric ozone become particularly important in spring, when returning sunlight allows them to alter stratospheric temperatures via shortwave heating, thus modifying atmospheric dynamics. At the same time, the stratospheric circulation undergoes a transition in spring with the final stratospheric warming (FSW), which marks the end of winter. A causal link between stratospheric ozone anomalies and FSWs is plausible and might increase the predictability of stratospheric and tropospheric responses on sub-seasonal to seasonal timescales. However, it remains to be fully understood how ozone influences the timing and evolution of the springtime vortex breakdown. Here, we contrast results from chemistry climate models with and without interactive ozone chemistry to quantify the impact of ozone anomalies on the timing of the FSW and its effects on surface climate. We find that ozone feedbacks increase the variability in the timing of the FSW, especially in the lower stratosphere. In ozone-deficient springs, a persistent strong polar vortex and a delayed FSW in the lower stratosphere are partly due to the lack of heating by ozone in that region. High-ozone anomalies, on the other hand, result in additional shortwave heating in the lower stratosphere, where the FSW therefore occurs earlier. We further show that FSWs in high-ozone springs are predominantly followed by a negative phase of the Arctic Oscillation (AO) with positive sea level pressure anomalies over the Arctic and cold anomalies over Eurasia and Europe. These conditions are to a significant extent (at least 50 %) driven by ozone. In contrast, FSWs in low-ozone springs are not associated with a discernible surface climate response. These results highlight the importance of ozone–circulation coupling in the climate system and the potential value of interactive ozone chemistry for sub-seasonal to seasonal predictability

Data-dependent fairing of subdivision surfaces

In this paper we present a new algorithm for solving the data dependent fairing problem for subdivision surfaces, using Catmull-Clark surfaces as an example. Earlier approaches to subdivision surface fairing encountered problems with singularities in the parametrization of the surface. We address these issues through the use of the characteristic map parametrization, leading to well defined membrane and bending energies even at irregular vertices. Combining this approach with ideas from data-dependent energy operators we are able to express the associated nonlinear stiffness matrices for Catmull-Clark surfaces as linear combinations of precomputed energy matrices. This machinery also provides exact, inexpensive gradients and Hessians of the new energy operators. With these the nonlinear minimization problem can be solved in a stable and efficient way using Steihaug's Newton/CG trust-region method. We compare properties of linear and nonlinear methods through a number of examples and report on the performance of the algorithm