263134 research outputs found
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Elektrisch-veldgestuurde omkeerbare transformatie van zelf-geassembleerde moleculaire netwerken van arylboorzuur naar tweedimensionale polymeren
No full text1、evaluate the influence of the choice of solvent, concentration of monomers and the deposition temperature on the outcome of the 2D polymerization process. 2、actively seek to influence the nucleation and growth processes by changing the electric field that exists between the STM tip and the sample, or between a conductive AFM tip and the sample. 3、deeply investigate the exact role of electric field in triggering and influencing the 2D polymerization process.status: Publishe
Diverse ensemble cost-sensitive logistic regression
No full textsponsorship: This work was supported by the China Scholarship Council [202209110031] and the Flemish Government, Belgium under the "Onderzoeksprogramma Artificiele Intelligentie (AI) Vlaanderen" program. The resources and services used in this work were provided by the VSC (Vlaams Supercomputer Center) , funded by the Research Foundation-Flanders (FWO) , Belgium and the Flemish Government, Belgium. (China Scholarship Council|202209110031, Flemish Government, Belgium, Research Foundation-Flanders (FWO) , Belgium)status: Publishe
Assessment of the dynamic nature of upper gastrointestinal pH: A pooled analysis using the fluid aspiration technique
No full textThis manuscript compiles a set of temporal pH profiles of the upper gastrointestinal (GI) tract under varying physiological and pharmacological conditions, including water and food intake as well as proton pump inhibitor (PPI) co-medication. A pooled analysis was conducted using data from 19 clinical studies previously performed in our laboratory, all of which employed standardised protocols and measurement techniques. Intraluminal pH was recorded in aspirated samples from the gastric antrum, duodenum, and proximal jejunum. Test conditions involved administering 240 to 250 mL of water in either the fasted state, the fed state after intake of the nutritional supplement Ensure Plus, or the fasted state with co-medication of esomeprazole. Trends in time-dependent pH were visualised using generalised additive models for location and shape (GAMLSS). Fed state profiles showed different temporal pH developments compared to the fasted state post water ingestion in the stomach and duodenum. An exploratory analysis using an FDA-standard high-fat breakfast yielded pH profiles similar in shape to those with Ensure Plus, though with a trend towards lower median pH values. Co-administration of esomeprazole resulted in pH increases not only in the stomach but also in the duodenum and jejunum, compared to the fasted state. These findings provide detailed insight into the dynamic luminal pH environment of the upper GI tract, potentially relevant to the design, optimisation, and evaluation of oral dosage forms. Furthermore, the provided data may support the development and refinement of in silico tools used to predict oral drug behaviour.sponsorship: This work has received funding from Horizon 2020 Marie Sklodowska-Curie Innovative Training Networks program under grant agreement No. 956146. TV is supported by a senior clinical research fellowship (1830522N) from the Flanders Research Foundation (FWO Vlaanderen). The authors would like to thank all collaborators who contributed to the clinical studies included in this manuscript and L BioStat for their valuable support in statistical analysis.Artwork depicting tablets, the human body, beverages and arrows, as presented in the graphical abstract, were sourced or adapted from images available through Servier Medical Art (Servier; https://smart.ser vier.com/) and are licensed under a Creative Commons Attribution 4.0 Unported License. Further illustrative elements were sourced from Open Clipart (https://openclipart.org/) and are licensed under a Creative Commons Zero 1.0 Public Domain License. (Horizon 2020 Marie Sklodowska-Curie Innovative Training Networks program|956146, Flanders Research Foundation (FWO Vlaanderen)|1830522N)status: Accepte
Hedging against inflation: Are listed infrastructure assets effective?
No full textIn this article, we examine the inflation-hedging potential of listed infrastructure. To do so, we determine the optimal portfolio allocation that minimizes the downside risk for a given inflation-linked target return by using different lower partial moments (LPMs) as risk metrics. We simulate returns by a GARCH-copula model to flexibly allow for well-known return properties. We assess the potential of both an overall infrastructure index and sector-specific indexes representing transportation, telecom, and utilities. We find that listed infrastructure not only improves a portfolio’s inflation resilience but also increases its expected return. This result might be particularly relevant for long-term, liability-driven investors such as pension funds and insurance companies.status: Publishe
Hoge druk vloeistofchromatografie gekoppeld aan tandem massaspectrometrie voor de gerichte bioanalyse van aminozuren
No full textThe amino acid profile has shown its significance in various pathological conditions, such as cancer, metabolic and polycystic diseases. In this study, high performance liquid chromatography methods will be developed to quantify the main amino acids in various biological matrices, in support of biomedical research. Tandem mass spectrometry as a detection mode can alleviate the absence of a UV-chromophore in many amino acids.status: Accepte
Competentiegerichte Teamontwikkeling voor Software Engineering Projecten: Uitgebreide Competentiemodellen
No full textThe present research project, titled "Competence-Based Team Development for Software Engineering Projects: Comprehensive Competence Models", addresses shortcomings in current project staffing approaches, including team formation and development. Such staffing approaches (1) usually consider only day/skill combinations, which simply sum up to the projects results, and (2) still rely on subjective opinions of project and team leads. Although this is not realistic and efficient: (1) adding up workdays does not per se result in project success, and (2) project integration and cooperative work efforts should be considered, preferably in more objective manner.
Therefore, the research project aims at extending the existing theory of competence models by related operations for competence-based staffing (including team formation and development) within software engineering projects. Thus, the main research goals (RGs) of the present research project are to investigate:
RGI: the operationalisation of project staffing based on formally captured competence profiles, leading to improved methods for team formation and development in engineering projects,
RGII: the existing competence models for formally captured competence profiles which include the required information for competence-based project staffing, and
RGIII: dynamic aspects in competence development and interrelation of competences which influence teamwork and the development of individual and team competence profiles (including learning effects).
The stated objectives have been achieved by answering the following main research questions (RQs) of the study:
RQI: Which competence models can provide formal descriptions of competence profiles?
RQII: What essential elements and operations do competence models need to provide to make them useful?
RQIII: Which applications are enabled by formally captured competence profiles?
In total eight peer-reviewed contributions have been compiled to answer the stated research questions, broken down to respective sub-questions, hypotheses, and research goals. The research design, as part of Design Science Research, followed the funnel paradigm, coming from general to specific and back (from specific to general) for valorisation purposes.
The core research investigations were conducted while answering the first two main research questions. The study "Towards a competence model for project team formation: a case of software engineering teams" showcases what should be operationalised in competence-based approaches to overcome team formation issues in software engineering projects (e.g., subjectivity while forming the teams or complexity of project environment), while "Taxonomy of competence models based on an integrative literature review" explains how competence profile descriptions should be described with competence models, to be later operationalised within various contexts.
The operational requirements were retrospectively reflected in the earlier studies, which were conducted before the taxonomy of competence models was developed. This analysis allowed building up relevant implications for industry and education, valorising the findings, and eventually answering the last question of the present study.status: Publishe
Fundamenten en algoritmes voor 3D onregelmatige cutting en packing problemen
No full text3D irregular cutting and packing problems concern the challenge of efficiently arranging arbitrarily shaped three-dimensional objects inside bigger containers. Examples of such problems include the packing of products in boxes, the compacting of 3D printing layouts, and the extraction of desirable shapes from raw pieces of material. The goal in these problems is typically to either minimize the volume used or to maximize the value of objects that are arranged. These are particularly difficult optimization problems to solve, given the compounding challenges of (i) working with three-dimensional irregular geometry and (ii)~the~inherent combinatorial complexity of packing problems. This fusion of geometric and combinatorial complexity forms a high barrier to entry for researchers and developers wishing to tackle these problems. This helps explain why despite the practical relevance of such problems in our three-dimensional world, they have received relatively little attention in the scientific literature. The situation is further exacerbated by the lack of open-source implementations for the few methods that do exist, which limits the ability to reproduce and build upon previous work.
With this thesis, we aim to address the aforementioned shortcomings that currently affect 3D irregular cutting and packing research. We consider two vastly different problem variants: the strip packing problem and the volume maximization problem. For both problems, we succeed in pushing the boundaries of the previous state-of-the-art solution methods, both in terms of exact and heuristic methods. In doing so, we address the relatively limited attention these problems have received in the scientific literature and the lack of exact methods more specifically. Advancing the capabilities of exact methods is important, even though one can safely assume heuristic approaches will outperform exact solution methods for problems of real-world scale and complexity. The limits of exact methods properly substantiate the need for heuristics, and allow us to better understand and evaluate their performance.
To help lower the barrier to entry for future researchers, we introduce an open-source software library: MeshCore. This library provides the core functionality needed to manipulate three-dimensional objects, implement packing algorithms, and visualize solutions. In doing so, MeshCore enables rapid prototyping of 3D irregular cutting and packing algorithms. Throughout this thesis, MeshCore is used as a reusable foundation beneath all the algorithms we introduce. Our experiments prove that MeshCore is a suitable tool for addressing a variety of problems and performant enough to support the development of state-of-the-art heuristics. In addition to making MeshCore open source, we also chose to make the implementation of all our algorithms publicly available. This is to actively counteract our concerns regarding the verifiability and reproducibility of academic research in the area of 3D irregular cutting and packing.
In addition to making significant academic contributions through publicly available algorithms, this thesis will also explore the impact our research achieved in an industrial context. In collaboration with a diamond processing company, we developed optimization software for maximizing the value of polished diamonds that can be extracted from a rough stone. This case study highlights how the algorithms we develop can have a significant positive impact on real-world applications.
One thing that became clear to us throughout the course of this thesis is that the field of 3D irregular cutting and packing is still in many ways in its infancy. Not only in terms of solution methods, but also in other aspects like reproducibility. While we significantly improve upon the previous state of the art for the two problems we address, most of our contributions should be considered foundational in nature. This is because they tackle basic problem variants, concern novel solution strategies, or are the first adaptation of established techniques from related fields. Therefore, many open challenges and opportunities remain for future research in this area, which we feel confident will benefit from our open source MeshCore library.status: Publishe
Exploring interactions in microbial communities
No full textMost microbial ecosystems cannot be understood without quantifying ecological interactions between their member species. Given the challenges of comprehensively resolving interactions experimentally, a range of prediction methods was developed. Here, we review genome-based prediction methods in particular and discuss their strengths and weaknesses. We then cover different experimental designs to explore microbial interactions and introduce methods to infer interaction signs and strengths from experimental data. Despite the range of available methods to study microbial interactions in silico and in vitro, interactions in a spatial context are still underexplored, and we lack comprehensive interaction databases, which are important gaps to fill in the future.sponsorship: We thank all current and former members of the lab of Microbial Systems Biology and Didier Gonze for informative discussions. XZ is the recipient of a scholarship from the China Scholarship Council (Certificate No. 202306350040) . AGD has received funding from the European Union's Horizon Europe research and innovation program under the Marie Sklodowska-Curie grant agreement No. 101169005. (China Scholarship Council|202306350040, European Union's Horizon Europe research and innovation program under the Marie Sklodowska-Curie grant|101169005)status: Publishe
Meerdere mineralisatie- en fluïda migratiefasen in de Centraal-Afrikaanse Copperbelt – Implicaties voor de datering van de ertsvormende processen
No full textVarious models have been proposed for the ore-forming processes of sediment-hosted Cu-Co deposits in the Central African Copperbelt, ranging from a magmatic to syn-sedimentary, diagenetic and orogenic origin or a multiphase origin. The isotopic systems Re-Os and U-Pb have been applied with success to date the mineralizing processes in the Copperbelt. However, a problem with this approach is the wide and sometimes geologically unrealistic ages obtained by Re-Os and U-Pb dating of the ore minerals. The large range in mineralization ages reported for the Cu-Co ore deposits in the Copperbelt can be due to a variety of geological processes. They could reflect: 1) multiple mineralization phases, as described for both the Congolese and Zambian part of the Copperbelt, 2) remobilization and recrystallization during subsequent fluid flow events, and 3) resetting of the isotopic system during later heating or fluid flow periods. The aim of this research is to: 1) characterize petrographically and geochemically the different mineralization, remobilization and recrystallization phases, 2) to propose objective criteria to distinguish these different phases and 3) to age date (U-Pb) the different carbonate phases associated with both barren as well as mineralized phases.status: Publishe