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Towards optimizing the opportunities and minimizing the risks of offshore wind farms for the benthic environment
No full textDit werk onderzoekt de milieueffecten van offshore windmolenparken (WPM) op de epibenthische gemeenschap van artficiële en beschermde natuurlijke hard substratenen verkent de verenigbaarheid tussen toekomstige WMPs en natuurbehoud. Het onderzoek werd uitgevoerd via een combinatie van analyse van lange-termijnsdata en in-situ- en laboratoriumexperimenten. Uit de bevindingen blijkt dat de biofoulinggemeenschappen worden beïnvloed door factoren als successiestadium, locatie, diepte en biologische interacties.Verder bleek dat een verhoogde structurele complexiteit van de artificiële structuren gepaard gaat met een hoger biodiversiteit, terwijl het type materiaal waarmee gebouwd wordt geen invloed heeft. Het is echter ook duidelijk dat de bouw van WMP negatieve effecten kan hebben op nabijgelegen beschermde harde substraatsoorten, zodat de plaatsing van de turbines in de onmiddellijke nabijheid van natuurlijke harde substraten zorgvuldig moet worden overwogen. Deze bevindingen van dit proefschrift dragen bij tot een beter begrip van de ecologische gevolgen van WMPs en benadrukken het belang van een goed evenwicht tussen de ontwikkeling van hernieuwbare energie en natuurbehoud
The microbial composition of bovine colostrum and its relation to the passive transfer of immunity
No full textThe neonatal phase presents significant challenges in a calf's life. Proper colostrum management ensures a robust transfer of passive immunity and assumes a crucial role in diminishing the likelihood of illness and mortality during this period. Colostrum contains a multitude of advantageous components for the calf's immunity, growth, and development, the best known of which are antibodies. The absorption of antibodies in calves is most efficient within the initial hours after birth and diminishes significantly after the first 24 hours. The efficacy of this absorption is influenced by more than just the quantity of antibodies ingested; it's hypothesized that other colostrum components and calf-specific factors also contribute to the efficiency of IgG absorption in the gut. Colostrum also contains a diverse microflora, and its consumption seems to play a pivotal role in initiating the colonization of the neonatal calf's intestinal tract and promoting gut health
Understanding mathematical learning experiences and achievement from an Opportunity-Propensity perspective in children with and without Mathematical Learning Disabilities
No full textMolecular characterization of SOX11 as multifaceted epigenetic regulator in neuroblastoma
No full textNeuroblastoma (NB) is the most common extra-cranial solid childhood cancer with a relapse rate of nearly 50% in high-risk NB cases, after which limited treatment options are available. Additionally, intensive multimodal treatment often leads to long-term side effects in survivors, highlighting the urgency for more precise therapy options to improve therapeutic effectiveness while minimizing adverse effects. Therefore, a comprehensive understanding of the molecular pathways and factors influencing NB progression is essential for the development of novel targeted therapeutic strategies.
The genomic landscape of NB exhibits a relatively low mutational burden. However, it is characterized by highly recurrent chromosomal structural rearrangements. Additionally, NB cells can co-opt normal developmental programs, relying on developmental master transcription factors (TFs) for survival and tumor progression. Using a targeted search for lineage-dependent TFs important in neurogenesis and affected by copy number alterations, we identified the neuronal-specific TF SOX11 as the sole protein-coding gene in the shortest region of overlap for amplicons at chromosome 2p distal to MYCN. We additionally characterized SOX11 as a dependency TF based on its specific expression in the normal sympatho-adrenal lineage and adrenergic (ADRN) NB tumors and cell lines, its regulation by multiple ADRN specific (super-)enhancers and its strong dependency on high SOX11 expression in ADRN NBs.
Using transcriptome analysis after SOX11 knockdown and overexpression, we have successfully identified the SOX11 regulome, encompassing the regulatory factors and pathways that play a significant role in shaping the ADRN NB phenotype. This revealed regulation by SOX11 of multiple functions related to cell migration, cytoskeleton, neuronal differentiation and a broad regulatory effect on multiple epigenetic regulatory factors and protein complexes. Furthermore, in order to gain a more comprehensive understanding of the specific target genes directly bound by SOX11, we employed SOX11 CUT&RUN-sequencing in adrenergic NB cells and the mesenchymal NB cell line SH-EP following SOX11 overexpression. This revealed a direct effect of SOX11 on multiple core and subunit specific SWI/SNF components as well as several other proteins implicated in diverse epigenetic regulatory processes.
The two distinct NB differentiation states, namely adrenergic (ADRN) and mesenchymal (MES), are characterized by specific core regulatory circuitries (CRC) consisting of interconnected lineage-specific TFs regulated by super-enhancers. We identified SOX11 as integral part of the ADRN CRC based on SOX11, as well as other CRC members, binding to the SOX11 promoter and enhancer landscape. Furthermore, SOX11 directly regulates other CRC members and partial collapse of the ADRN CRC is observed after SOX11 knockdown. However, SOX11 knockdown alone is inadequate to induce a complete ADRN-to-MES transition, implying that additional factors are required for lineage switching in NB. Based on current data and the direct effect of SOX11 op chromatin remodeling, we postulate that SOX11 plays a role in epigenetic plasticity and maintenance of the ADRN CRC.
Lineage specific functions of SOX TFs are highly dependent on recruitment of interactions partner. We used rapid immunoprecipitation and mass spectrometry (RIME) to map the interactome of SOX11 showing interaction with spliceosome complex proteins and other splicing regulators. SOX11 overexpression indeed influences alternative splicing events, suggesting a dual role in RNA splicing by interacting with splicing regulators as well as controlling their transcription. In silico analysis further shows strong dependency on interaction between SOX11 and the paraspeckle protein NONO, particularly in high-risk MYCN-amplified NB cases, with our data suggesting an interplay between SOX11 and NONO in RNA splicing.
Overall, these findings suggest that SOX11 acts as a multifaceted epigenetic regulator through direct regulation of the SWI/SNF complex and interaction with the splicing machinery, with current data suggesting a role in epigenetic plasticity and maintenance of the ADRN CRC in NB. In addition, we identified multiple promising therapeutic targets which are under further investigation facilitating the identification of potential drug targets
Management of plant-parasitic nematodes with cover crops in rotations with open field vegetable crops
No full textDue to the intensive nature of vegetable cultivation in the open air, problems with plantparasitic nematodes such as the root lesion nematode Pratylenchus penetrans and the
quarantine root-knot nematode Meloidogyne chitwoodi have increased in recent years.
The aim of this research was to increase the knowledge about the damage threshold and
host plant status of some commonly used vegetable cultivars in Flanders, combined with
knowledge about the host plant status of cover crops for M. chitwoodi and P. penetrans.
Differences between cultivars of vegetable crops and cover crops were reported both, in
pot and field tests. Spinach can be included in rotation schemes to control M. chitwoodi
if the field period is short enough and the stubble is destroyed after harvest. All pea
cultivars tested and celeriac were good hosts for M. chitwoodi. Pea and leek can increase
populations of P. penetrans with potentially severe yield loss. Results from the cover crop
experiments showed that populations of M. chitwoodi and P. penetrans can be lowered
with cover crops. The fodder radish cultivars used that are M. chitwoodi resistant gave a
lower reproduction of P. penetrans compared to the susceptible M. chitwoodi cultivar
'Radical'. This showed that M. chitwoodi-resistant fodder radish has the potential to be
further developed for concomitant P. penetrans resistance. Field trials with cover crops
followed by nematode-susceptible or non-susceptible vegetable cultivars showed that for
both, M. chitwoodi and P. penetrans, rotations can be developed that allow profitable
yields in combination with a reduction of the harmful nematode population.In Vlaanderen-België is openluchtgroenteteelt een belangrijke economische activiteit voor de verse consumptie en de industrie. De Vlaamse diepvriesgroente-industrie is wereldmarktleider. In 2021 bedroeg de export 1,4 miljoen ton diepvriesgroenten met een positieve handelsbalans van 899 miljoen euro (groentebarometer VLAM). Door het intensieve karakter van de groenteteelt in de open lucht zijn problemen met plantenparasitaire nematoden zoals de wortellesienematode Pratylenchus penetrans en de quarantaine wortelknobbelnematode Meloidogyne chitwoodi de laatste jaren sterk toegenomen. Het doel van dit onderzoek was het vergroten van de kennis over de schadedrempel en waardplantstatus van enkele veelgebruikte groentecultivars in Vlaanderen, gecombineerd met kennis over de waardplantstatus van groenbedekkers voor M. chitwoodi en P. penetrans. Deze kennis moet toelaten om rotatieschema’s te ontwikkelen die deze nematoden beheersen, waardoor een winstgevende groenteproductie in Vlaanderen mogelijk blijft. Geteste spinaziecultivars waren waardplanten voor M. chitwoodi maar verschillen tussen cultivars bieden kansen voor resistentieveredeling. Met geselecteerde cultivars kan populatieopbouw en schade worden voorkomen. Spinazie kan worden opgenomen in rotatieschema's om M. chitwoodi te beheersen indien de veldperiode kort genoeg is en de stoppel na de oogst wordt vernietigd. Alle geteste erwtencultivars waren goede waardplanten voor M. chitwoodi. Knolselderij was een uitstekende waardplant in de pottest en op percelen met de laagste opbrengst werd een groot aantal M. chitwoodi in de wortels aangetroffen. Het telen van erwten en knolselderij in met M. chitwoodi besmette velden kan de problemen met deze nematode vergroten. Voor knolselderij is de schade beperkt, maar met zijn lange veldperiode kan M. chitwoodi meer dan 1 generatie vormen. Geteste spinaziecultivars waren matige waardplanten voor P. penetrans, knolselder was een uitstekende waardplant. Cultivarverschillen bij spinazie voor P. penetrans bieden mogelijkheden om opbrengstverliezen en populatieontwikkeling te beperken. Het telen van erwten en prei in met P. penetrans aangetaste velden kan de problemen met deze nematodensoort vergroten met een aanzienlijk potentieel opbrengstverlies. De waardplantstatus van verschillende cultivars van groenbedekkers voor M. chitwoodi en P. penetrans werd onderzocht. Resultaten van pot- en veldexperimenten toonden aan dat bladrammenascultivars met M. chitwoodi-resistentie zeer goede resultaten gaven bij het terugdringen van de M. chitwoodi-populatie. Het infectieproces en de interactie van P. penetrans en M. chitwoodi op bladrammenascultivars werd onderzocht. De gebruikte bladrammenas cultivars die M. chitwoodi-resistent zijn, gaven een lagere reproductie van P. penetrans in vergelijking met de vatbare M. chitwoodi cultivar 'Radical'. Gelijktijdige infectie van 'Doublemax' met beide aaltjessoorten had geen invloed op de resistentie tegen M. chitwoodi. Ons onderzoek toonde aan dat M. chitwoodi-resistente bladrammenas het potentieel heeft om verder ontwikkeld te worden voor gelijktijdige P. penetrans-resistentie. Veldproeven met groenbedekkers, gevolgd door nematodengevoelige of niet-gevoelige groentecultivars toonden aan dat voor zowel M. chitwoodi als P. penetrans, rotaties kunnen worden ontwikkeld die een winstgevende opbrengst mogelijk maken in combinatie met een vermindering van de schadelijke nematodenpopulatie
Modulation of bacterial metabolism to potentiate antibiotic efficacy against Pseudomonas aeruginosa biofilm infections
No full textRheology of alkali-activated materials : from microstructural evolution to the flow of concrete
No full textHet hoofddoel van dit proefschrift is om nieuwe inzichten te geven in het reologische gedrag van alkali-geactiveerde materialen (AAM's). Vanaf het pasteniveau zijn de microstructurele kenmerken van alkali-geactiveerde slakkenpasta (AAS) gevisualiseerd, wat helpt bij het begrijpen van reologie en het vroege verstevigen proces in AAS. Verder werd de reologie (in termen van opbrengstspanning, viscositeit, thixotropie en niet-lineair gedrag) van alkali-geactiveerd beton (AAC) uitgebreid bestudeerd door de toegepaste activator, voorloper en toevoegingen te variëren. De resultaten hebben de haalbaarheid onderzocht om de verse eigenschappen van AAM beton goed te beheersen door de ontwerpparameters van de mix te wijzigen. Tenslotte worden de gegevens van AAC verzameld voor verdere statistische analyse, die de relatie tussen mix ontwerpparameters en het reologische gedrag van AAC onthult via een kunstmatige intelligentie (AI) benadering. Een inverse single-objective optimalisatie in Ms is uitgevoerd op basis van de RF-modellen verkregen om natriumsilicaat in activatoren verder te verminderen, dat wordt beschouwd als de belangrijkste koolstofemissiebron in AAMs. Verwacht wordt dat de onderzoeksresultaten de toepassing van AAM's in grootschalige bouwgebieden kunnen bevorderen
Explanation in the engineering sciences : IBE, causal modelling, and (fictional) mechanisms in failure analysis and safety science
No full textThis dissertation investigates explanation in the engineering domains of failure
analysis and accident causation. Explaining accidents and failures is important
for learning, preventing, repairing and in some cases figuring out responsibility.
The work presented here aims to clarify some widespread explanatory practices,
strategies, and formats in these domains, using insights and accounts from
philosophy of science.
A series of case studies are used to highlight the structure and value of
explanatory practices within engineering science. The crash of Air France 447 is
used to highlight the way in which different explanations are evaluated when
unequivocal evidence is missing. Analysing this case highlighted, among other
things, that in failure analysis an important criterion driving the explanation is
the ability to provide valuable redesign information. This insight is further
exemplified in other cases such as malfunctioning Samsung Galaxy 7 mobile
devices.
Another interesting result stems from analysing how engineers explain the
breaking of metals and other ductile materials. One key factor in explaining
these ruptures is the presence of small voids, which when merging together to
a sufficient extent provoke the disjointing of metal pieces. The explanatory
strategy employed here is that of a mechanical story, despite voids or holes not
being the sort of entity that can behave mechanically. An analysis of how these
explanations work is presented together with a description of the cognitive
benefits they provide.
In addition to looking at concrete case studies, the dissertation also looks at the
modelling practices used when analysing the causality of accidents. The way in
which the causality of accidents is modelled has a direct impact on
understanding and preventing accidents, as well as on the adjudication of legal
responsibility. Different modelling strategies encode differing causal
information, resulting in key differences in applicability, scope, effectiveness,
and explanatory power. An account of the value of the most important
modelling practices is put forward, regimented by precise tools from philosophy
of science which highlight the relevant trade-offs each modelling approach
offers. This analysis allows to make suggestions as to which modelling strategy
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is best suited to achieve specific aims, such as preventing accidents or
adjudicating legal responsibility.
Finally, key philosophical and theoretical tools are employed in building a
procedure which aims at improving the practice of Failure Analysis. This
procedure structures the information contained in explanations such that it
enables to find weak points, to compare competing explanations, and to provide
redesign recommendations. In doing so it becomes a tool for assessing the
quality of failure explanations. The procedure offers failure analysts a practical
tool for critical reflection on some areas of their practice while offering a deeper
understanding of the workings of failure analysis (by framing it as an explanatory
practice) and redesign. Two case studies from Mechanical and Civil Engineering
are used to exemplify how the procedure works/is intended to work
