Detecting natural canopy gaps in Amazonian rainforest

En établissant des conditions particulières, les chablis contribuent au maintien de la richesse spécifique des forêts. L'étude présentée sur les chablis dans les forêts de Guyane française s'appuie sur des images Spot de 20 m de résolution, qui ont permis de détecter les trouées dans la canopée, sur une large échelle. Les structures et l'écologie de onze trouées sont analysées sur le terrain, au sol et dans la canopée: la repousse à l'intérieur du chablis, les indices foliaires, les espèces d'arbres concernées par la chute ainsi que la topographie du site. À partir de ces données, chaque chablis est cartographié et localisé finement grâce au Gps (Global positioning system). Un filtre d'image binaire, comprenant trois bandes spectrales (visible, proche infra rouge, infrarouge à courtes longueurs d'onde), différencie les chablis de leurs environnements forestiers. Les résultats montrent que la trouée doit potentiellement occuper 25 à 50% du pixel pour être détectée. La vigueur de la repousse (hauteur et densité) empêche la détection des chablis trop anciens, en cours de fermeture. Les variations topographiques, les ombres et la position relative du chablis dans le pixel influencent également la qualité de la détection. Cette étude nécessite d'autres développements pour améliorer la résolution de l'image satellitaire ainsi que le filtre de détection, afin de pouvoir étudier, à l'échelle du paysage, ce processus caractéristique de la dynamique des forêts tropicales. (Résumé d'auteur

A seed-specific regulator of triterpene saponin biosynthesis in Medicago truncatula

Plants produce a vast array of defense compounds to protect themselves from pathogen attack or herbivore predation. Saponins are a specific class of defense compounds comprising bioactive glycosides with a steroidal or triterpenoid aglycone backbone. The model legume Medicago truncatula synthesizes two types of saponins, hemolytic saponins and nonhemolytic soyasaponins, which accumulate as specific blends in different plant organs. Here, we report the identification of the seed-specific transcription factor TRITERPENE SAPONIN ACTIVATION REGULATOR3 (TSAR3), which controls hemolytic saponin biosynthesis in developing M. truncatula seeds. Analysis of genes that are coexpressed with TSAR3 in transcriptome data sets from developing M. truncatula seeds led to the identification of CYP88A13, a cytochrome P450 that catalyzes the C-16α hydroxylation of medicagenic acid toward zanhic acid, the final oxidation step of the hemolytic saponin biosynthesis branch in M. truncatula. In addition, two uridine diphosphate glycosyltransferases, UGT73F18 and UGT73F19, which glucosylate hemolytic sapogenins at the C-3 position, were identified. The genes encoding the identified biosynthetic enzymes are present in clusters of duplicated genes in the M. truncatula genome. This appears to be a common theme among saponin biosynthesis genes, especially glycosyltransferases, and may be the driving force of the metabolic evolution of saponins

3D Line Radiative Transfer & Synthetic Observations with Magritte

Electromagnetic radiation is a key component in many astrophysical simulations. Not only does it dictate what we can or cannot observe, it can provide radiation pressure, efficient heating and cooling mechanisms, and opens up a range of new chemical pathways due to photo-reactions. Magritte is a software library that can be used as a general-purpose radiative transfer solver, but was particularly designed for line radiative transfer in complex 3D morphologies, such as, for instance, encountered in the stellar winds around evolved stars (see Decin, 2020). It is mainly written in C++ and can either be used as a Python package or as a C++ library. To compute the radiation field, a deterministic ray-tracer and a formal solver are employed, i.e., rays are traced through the model and the radiative transfer equation is solved along those rays (De Ceuster et al., 2019). This is in contrast to most radiative transfer solvers which employ (probabilistic) Monte Carlo techniques (Noebauer & Sim, 2019). By virtue of minimal assumptions about the underlying geometric structure of a model, Magritte can handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics (SPH) data. Furthermore, tools are provided to optimise different input meshes for radiative transfer (De Ceuster et al., 2020)

Industry-scale application and evaluation of deep learning for drug target prediction

Artificial intelligence (AI) is undergoing a revolution thanks to the breakthroughs of machine learning algorithms in computer vision, speech recognition, natural language processing and generative modelling. Recent works on publicly available pharmaceutical data showed that AI methods are highly promising for Drug Target prediction. However, the quality of public data might be different than that of industry data due to different labs reporting measurements, different measurement techniques, fewer samples and less diverse and specialized assays. As part of a European funded project (ExCAPE), that brought together expertise from pharmaceutical industry, machine learning, and high-performance computing, we investigated how well machine learning models obtained from public data can be transferred to internal pharmaceutical industry data. Our results show that machine learning models trained on public data can indeed maintain their predictive power to a large degree when applied to industry data. Moreover, we observed that deep learning derived machine learning models outperformed comparable models, which were trained by other machine learning algorithms, when applied to internal pharmaceutical company datasets. To our knowledge, this is the first large-scale study evaluating the potential of machine learning and especially deep learning directly at the level of industry-scale settings and moreover investigating the transferability of publicly learned target prediction models towards industrial bioactivity prediction pipelines.Web of Science121art. no. 2

M & L Jaargang 28/3

Sofie De Leeuw De Sint-Leonarduskerk van Zoutleeuw: kunstschrijn van Brabant.Dat de indrukwekkende sacramentstoren van Zoutleeuw maar één van de vele kunstschatten is van de rijke Sint-Leonarduskerk, wordt door Sofie De Leeuw kort geschetst.Dieter Nuytten De inventie van de sacramentstoren van Zoutleeuw: het oeuvre van Cornelis Floris en de artistieke Nederlanden tijdens de renaissance in de 16de eeuw. [The invention of the Zoutleeuw sacrament tower and the works of Cornelis Floris in the Low Countries art history of 16th century renaissance.]Dieter Nuytten situeert de sacramentstoren van Cornelis Floris binnen de noordelijke renaissance van de 16de eeuw en in het artistieke oeuvre van deze kunstenaar. Cornelis Floris als echte duivel-doet-al, toen uomo universalis genoemd, overschreed met ogenschijnlijk gemak de grenzen van de tot dan toe nauw omschreven ambachten en waagde zich zonder schroom zowel aan architectuur als aan tekeningen, drukwerken en beeldhouwwerken.Valérie Herremans De sacramentstoren als blikvanger in het historische kerkinterieur. [The sacraments tower as an eye-catcher in the historical church interior.]De merkwaardige ontwikkeling van de kleine pyxis, een bescheiden eucharistiedoosje, tot de overweldigende creatie van de Leeuwse sacramentstoren wordt door Valérie Herremans niet alleen vanuit zijn specifieke functie, maar ook vanuit een contextuele invalshoek belicht.Christina Ceulemans De iconografie van de sacramentstoren van Zoutleeuw: een grootse hulde aan het Heilig Sacrament. [The Zoutleeuw sacrament towers iconography: a magnificent hymn to the blessed sacraments.]Niet minder dan 180 beelden gaven, soms node, hun identiteit prijs aan Christina Ceulemans, die de voorstellingen beschrijft als een huldeprocessie aan de eucharistie. Dat een dergelijk ingewikkeld programma werd opgesteld door erudiete kerkgeleerden staat voor haar buiten kijf.Jan Verbeke en Jacques Vereecke Bouwtechniek van de toren. [Building technique of the sacraments tower.]Het gedetailleerde contract tussen Cornelis Floris en de mecenas Maarten Van Wilre levert precieze gegevens op over bouwtechniek en materialen. Toch kon het ervaren oog van de restaurateurs Jacques Vereecke en Jan Verbeke tal van andere bouwspecifieke technieken ontdekken, waarbij het spaarzaam omgaan met het dure materiaal en het onmiskenbare vakmanschap van dit goed georganiseerd atelier de leidraad bleken.Het petrografisch onderzoek van Francis Tourneur bevestigt Cornelis Floris aandacht voor de juiste materiaalkeuze.Summar

A Comprehensive Review on the Surgical Aspect of Lung Transplant Models in Mice and Rats

Lung transplantation improves the outcome and quality of life of patients with end-stage pulmonary disease. However, the procedure is still hampered by the lack of suitable donors, the complexity of the surgery, and the risk of developing chronic lung allograft dysfunction. Over the past decades, translational experiments in animal models have led to a better understanding of physiology and immunopathology following the lung transplant procedure. Small animal models (e.g., rats and mice) are mostly used in experiments regarding immunology and pathobiology and are preferred over large animal models due to the ethical aspects, the cost-benefit balance, and the high throughput possibility. In this comprehensive review, we summarize the reported surgical techniques for lung transplantation in rodent models and the management of perioperative complications. Furthermore, we propose a guide to help identify the appropriate species for a given experiment and discuss recent experimental findings in small animal lung transplant models

SARS-CoV-2 infections and impact of the COVID-19 pandemic in pregnancy and breastfeeding: Results from an observational study in primary care in Belgium

COVID-19 also affects pregnant and breastfeeding women. Hence, clinicians and policymakers require reliable evidence on COVID-19 epidemiology and consequences in this population. We aimed to assess the susceptibility of pregnant women to SARS-CoV-2 and women’s perceived impact of the pandemic on their breastfeeding practices, medical counseling and social support. We performed a cross-sectional study using an online survey in primary care in Belgium. Pregnant and breastfeeding women and women who breastfed in the preceding four weeks were eligible to participate. The survey was distributed through social media in April 2020. In total, 6470 women participated (i.e., 2647 pregnant and 3823 breastfeeding women). Overall, 0.3% of all respondents reported to have tested positive for SARS-CoV-2, not indicating a higher susceptibility of pregnant women to contracting COVID-19. More than 90% refuted that the pandemic affected their breastfeeding practices, nor indicated that the coronavirus was responsible for breastfeeding cessation. Half of the women even considered giving longer breastmilk because of the coronavirus. In contrast, women’s medical counseling and social support were negatively affected by the lockdown. Women without previous breastfeeding experience and in the early postpartum period experienced a higher burden in terms of reduced medical counseling and support. In the future, more consideration and alternative supportive measures such as tele-visits by midwives or perinatal organizations are required for these women

GrassPlot v. 2.00 – first update on the database of multi-scale plant diversity in Palaearctic grasslands

Abstract: GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). Following a previous Long Database Report (Dengler et al. 2018, Phyto- coenologia 48, 331–347), we provide here the first update on content and functionality of GrassPlot. The current version (GrassPlot v. 2.00) contains a total of 190,673 plots of different grain sizes across 28,171 independent plots, with 4,654 nested-plot series including at least four grain sizes. The database has improved its content as well as its functionality, including addition and harmonization of header data (land use, information on nestedness, structure and ecology) and preparation of species composition data. Currently, GrassPlot data are intensively used for broad-scale analyses of different aspects of alpha and beta diversity in grassland ecosystems