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Oxytocine over diersoorten heen: Van mechanismen bij knaagdieren tot implicaties voor gehechtheidsontwikkeling bij mensen
No full textOxytocin is a hypothalamic neuropeptide that was initially described as a prosocial hormone due to its positive effects on social behavior. Subsequent research, however, demonstrated that its effects are highly context- and person-dependent. More recent theories converge on the view that oxytocin does not directly promote prosociality, but instead modulates underlying mechanisms of both social and non-social behavior, such as social salience and prediction error processing. Prediction error refers to the discrepancy between expected and actual outcomes that drives learning.
The current dissertation investigated these mechanisms using the social transmission of food preference (STFP) paradigm, in which rodents learn about food safety by interacting with a conspecific. We conceptualized STFP acquisition as a functional parallel to human epistemic trust, or trust in communicated knowledge that enables humans to use social information to guide subsequent decision-making (Chapter 2). Within this framework, Chapter 3 showed that oxytocin enhanced trust-based learning but blocked updating after trust violation (prediction error) in male mice, but not in females. Chapter 4 extended these findings by demonstrating that oxytocin effects partly depended on dopamine signaling and were particularly evident in males for whom social information was less salient.
Building on the proposed parallel between rodent STFP acquisition and human epistemic trust, Chapter 5 synthesized evidence from oxytocin administration studies in both species. Meta-analyses revealed no uniform overall effect of oxytocin in rodents or humans, but substantial heterogeneity across studies. Narrative syntheses indicated that oxytocin can either enhance or reduce trust in social information depending on informant and recipient characteristics, as well as broader contextual factors. These findings are consistent with the allostatic model of oxytocin, which posits that oxytocin modulates information processing, learning, and prediction to support adaptive behavior.
Finally, Chapter 6 applied these mechanistic insights to human attachment development by examining whether children's oxytocin response to anticipatory stress moderated the association between parental support and changes in attachment across one year. Results showed that child-reported parental support predicted increases in trust, but this association was stronger for children with a higher oxytocin response to stress.
Taken together, this dissertation moves beyond the outdated view of oxytocin as a uniformly prosocial love hormone and advances a mechanistic account grounded in the allostatic model of oxytocin. By integrating the epistemic trust framework with the STFP paradigm, it establishes a translational approach to probe allostatic oxytocin effects and underlying neural mechanisms. This integration provides valuable tools to resolve longstanding paradoxes in oxytocin research and to develop precise accounts of how this ancient neuropeptide supports adaptive behavior. Ultimately, such insights can guide personalized and effective interventions in clinical and developmental contexts.status: Publishe
Naar praktische bootstrapping in volledig homomorfe encryptie
No full textFully homomorphic encryption supports arbitrary computations on encrypted data without requiring intermediate decryption. Even though it enables many promising applications, its adoption remains limited due to high computational overhead compared to unencrypted computations. A major cause is the need for an expensive bootstrapping algorithm, in which a homomorphic scheme evaluates its own decryption function.
This dissertation presents algorithmic and implementation improvements to the bootstrapping procedures of the encryption schemes from Brakerski-Gentry-Vaikuntanathan and Brakerski-Fan-Vercauteren. To this end, we propose some adaptations. Firstly, we study the structure of polynomial functions over the relevant domain of computation. This allows us to construct an interpolant for (a subcomponent of) the decryption function that can be efficiently evaluated. Secondly, we demonstrate how to homomorphically evaluate a class of structured linear transformations, which forms another integral part of decryption. Thirdly, we reduce the latency of bootstrapping by using a generalized version of the Brakerski-Fan-Vercauteren encoding mechanism. At the same time, our new encoding method enables computations on higher-precision numbers than what was previously possible.
The above improvements result in a bootstrapping algorithm that is not only more efficient, but also much easier to use and implement. In particular, at the start of this research, bootstrapping still took tens of seconds for practically useful security levels. Our most recent implementation can bootstrap in only a single second on a central processing unit in one thread, while simultaneously offering higher throughput and using a simpler mathematical construction.status: Accepte
Acoustische anomaliedetectie voor industriële machines: robuustheid, generaliseerbaarheid en betrouwbaarheidseigenschappen
No full textAcoustic Anomalous Detection (AAD) is the task of identifying whether the sound emitted from a target machine is normal or abnormal. Automatic detection of mechanical failure is an essential technology in the fourth industrial revolution, which involves artificial intelligence (AI)-based factory automation. Prompt detection of machine anomalies by observing acoustic signals is useful and necessary for monitoring the condition of machines. This PhD will address the following challenges: 1. In real-world factories, anomalies rarely occur and are highly diverse, which makes it difficult to obtain exhaustive patterns of anomalous sounds, and unknown anomalous sounds that were not observed in the given training data must be detected (i.e. unsupervised AAD). 2. In real-world cases, the operational conditions of machines or environmental noise often differ between the training and testing phases. For example, the operation speed of a conveyor can change due to seasonal demand, or environmental noise can fluctuate depending on the state of surrounding machines. 3. In test data, samples unaffected by domain shifts (source domain data) and those affected by domain shifts (target domain data) are mixed, and the source/target domain of each sample is not specified. Therefore, the model must detect anomalies with the same threshold value regardless of the domain (i.e., domain generalization). 4. Collecting data and detecting abnormal acoustic events in real-time using low-power IoT (IoT) systems in real-world factory applications requires techniques that can, on the one hand, minimize the amount of data to be transmitted and, on the other hand preserve essential data features.status: Publishe
Shareholder engagement voor duurzame Europese bedrijven - Meer dan alleen greenwishing?
No full textWhile a large part of the EU's sustainable finance strategy and its 2018 Action Plan has focused on regulating green financial products, less attention has been paid to the important relationship between companies and their shareholders. The Shareholders Rights Directive II (SRD II) was amended in 2017 to promote investor's engagement and support long-term, sustainable shareholdership. It is unclear if the tools the current Directive provides are sufficient, especially given the increased urgency and ambition the EU has shown since in tackling climate change Investor stewardship has the potential to steer companies towards a more sustainable path. Yet, the current financial system provides many incentives that interfere with this concept and lead to undue short-termism. There might be a gap between the EU's perception and aspiration of how it fosters active shareholdership and the reality, where skepticism towards its effectiveness is voiced, especially in light of the intermediary role large institutional investors and proxy advisors play. My research will investigate whether short-termism in stock markets justifies stricter shareholder and corporate governance rules to direct shareholders influence towards more sustainable and long-term choices and how stewardship can contribute towards the sustainability of companies. I will analyze the current EU framework and its implementation and conduct comparative research with other legal systems.status: Publishe
Buitencontractuele aansprakelijkheid voor milieugerelateerde angstschade, een rechtsvergelijkende en psychologisch geïnformeerde analyse
No full textIntroduction
Problem statement
Over recent decades, awareness of environmental dangers has grown, which is positive because understanding risks enables preparation and resistance. Fear for those dangers, too, can be useful as an evolutionary survival instinct, motivating action. However, when threats like earthquakes, toxicity or climate change become pervasive and seemingly unavoidable, fear turns into harmful dread. This harm may arise through unlawful imposition of risks. Illustrative cases include Groningen gas drilling causing earthquakes and constant anxiety, Manfredonia's chemical factory emitting arsenic and prompting ECtHR compensation for fear of accidents, and PFAS contamination in Antwerp creating long-term health risks and widespread worry. In modern society, where such environmental threats accumulate, the question needs to be asked: How should courts address the present harm caused by living under a sword of Damocles?
This phenomenon of harm resulting from fear has sparked concerns in legal scholarship. Some of them voice the floodgate argument, the concern that allowing such a claim would lead to mass litigation and insolvency issues. However, in this thesis, I focus on more fundamental legal questions. Indeed, harm resulting from fear challenges the DNA of extracontractual liability law, which traditionally focuses on personal interests, certain harm, and ex-post remedies. Can citizens invoke their fear for political issues as a personal interest and consequently use their fear as a basis for public interest litigation? Can fear for uncertain dangers circumvent the principle that extracontractual liability law traditionally applies to cases of certain harm? Lastly, can extracontractual liability law, which is traditionally conceived of as an ex-post mechanism, offer remedies that target the source of the fear and thus indirectly gain a preventive component?
Research question(s)
The aim of this thesis is to find a sound way for the Dutch and Belgian legal systems to deal with harm resulting from fear in environmental cases. To that end, the main research question is: How should the Dutch and Belgian legal system assess and incorporate claims for harm resulting from fear in environmental cases? To obtain a clear and thorough answer, the research is divided into a five-stage plan, each stage being accompanied by a separate subquestion.
How do the Dutch and the Belgian legal system currently assess and incorporate a claim for harm resulting from fear in environmental cases? I started by examining how harm resulting from fear can be embedded into the broader extracontractual liability law framework in Belgium and the Netherlands.
What are the main similarities and differences in the Belgian and the Dutch approach? After having studied the Dutch and the Belgian approach thoroughly, I compared the two. Despite their apparent conceptual differences, a functional comparative analysis revealed that the two legal systems reach highly similar results in practice.
In which ways can the Dutch and the Belgian approach to harm resulting from fear draw inspiration from the French and American approaches? While the French and American legal systems have not been subject to a thorough comparison, they have provided inspiration, especially regarding the assessment of the reasonability of a fear.
In which ways can psychological research on solastalgia help legal systems in understanding and assessing extrapatrimonial harm in environmental cases? I employed a scoping review to inform the legal approach to harm resulting from fear with a psychological perspective. Solastalgia, i.e. the psychological experience of changes to a familiar environment, was central to this research stage.
How should the Dutch and Belgian legal system assess and incorporate harm resulting from fear claims in environmental cases? Finally, I evaluated the results found throughout the text, using a normative framework that considers the psychological perspective, the victim-perspective and a sustainability perspective, without deconstructing the foundations of extracontractual liability law.
Structure of the study
In the first chapter, fear and liability, I give a general introduction to liability for harm resulting from fear, with some background information that can be useful for the reader to remember throughout the analysis. In the second chapter, fear and solastalgia, I introduce the reader to solastalgia and its surrounding body of literature. I delve into the concept, the main empirical findings it has led to and the reasons why it is well-suited for a legal but psychologically informed analysis. In the third chapter, fear and harm, I delve into the harm aspect of claims for harm resulting from fear. I first study the notion of harm up close. Subsequently, I apply it to harm resulting from fear in an environmental context. I also point out that harm resulting from fear can be presumed. In the fourth chapter, fear and reason, I delve into questions that revolve around unreasonable fear. I search for legal bases to limit unreasonable fear, and I develop a test with which to measure the reasonability of fear. In the last chapter, fear and relief, I provide an overview of remedies that can be ordered in cases of harm resulting from fear, with an emphasis on preventive opportunities.
Main results
Chapter 1. Fear and liability
This first chapter serves as an introduction to extracontractual liability law encountering harm resulting from fear. First, it gives a brief overview of how harm resulting from fear has been received in the various legal systems relevant to the present study. In all legal systems, the context of toxic exposure provided fertile ground for the claim to blossom. However, in many of them, the harm resulting from fear is slowly but surely making its way to other types of cases, such as the earthquakes case in Groningen, the PIP-scandal in France and climate change litigation in Belgium. The question remains: how to accommodate those current and future applications of harm resulting from fear?
Second, the chapter introduces the reader to a first vital aspect of extracontractual liability law, namely the criterion of fault. Even though fault is by no means the most relevant criterion for harm resulting from fear, which pertains mostly to aspects of harm and causality, it is important to emphasize that liability necessitates a liability-inducing fact. Additionally, this short analysis introduces the reader to a few basic aspects of fault that can be of some importance in cases of harm resulting from fear. A fault can consist of a violation of a specific norm or a general norm of due care. In most cases in environmental liability law, the plaintiffs need to fall back on the second, more open norm. Furthermore, the nature of the fault is, in most cases, of no consequence to how the judge deals with harm resulting from fear. Lastly, and most importantly, the principle of relativity could potentially impede harm resulting from fear claims. Even though I have not encountered any explicit examples so far, the analysis shows that its potential role should not be underestimated.
Chapter 2. Fear and solastalgia
In the second chapter, I introduce the reader to solastalgia. That term describes the psychological experience of negatively perceived changes to a familiar environment. Solastalgia describes a personal form of harm suffered due to concrete negative changes to the environment. This renders it an appropriate notion in the context of extracontractual liability law, that mainly applies to questions of personal interests. Additionally, this preliminary assessment of the solastalgia literature shows that the notion can be highly relevant in a legal context. It emphasizes a form of harm that has not yet been denoted as such in legal practice or legal scholarship. Adopting the term in a legal context could support a broader recognition of the non-economic losses associated with environmental change. Additionally, the impact factors identified in the empirical literature could help point the attention of the judge in the right direction when assessing or measuring solastalgia and its severity.
Chapter 3. Fear and harm
In the third chapter, I first present a deep dive into the concept of harm. I have rejected its dual understanding, in which patrimonial harm consists of the loss of an object (objectivism) and extrapatrimonial harm consists of a deterioration of the subject (subjectivism). Instead, I proposed a unified phenomenological understanding, where harm always consists of the loss of a certain value, i.e. the loss of a certain connection between subject and object. In some cases, that connection can be described as possibilities, opportunities, or need satisfaction capacity, but those terms sell the notion of harm short. Extracontractual liability law does not only intervene for loss of instrumental value but also awards indemnification for the loss of existential value, where the subject has a meaningful bond with a certain object. Applied to harm resulting from fear, harm does not consist of an objective exposure to a risk (objectivist approach) or of pure fear (subjectivist approach). It consists of the loss of value that springs from fear.
Consequently, I showed that the phenomenological approach to harm resonates well with the relevant case law. I first studied the broader case law on environmental harm, which can be subdivided into two concepts of harm. First, harm to the environment denotes the somewhat controversial view that nature can experience harm. In this study, I focus on the second, namely human harm that came into being via the environment. Within this anthropocentric type of harm, I distinguish harm to general values from harm to personal values, i.e. personal harm. Both Belgian and Dutch law require the plaintiff to establish that they have been affected personally, i.e. in a way that is more specific than the way in which everyone else is affected. A notion like eco anxiety, which describes a world-wide loss of mental health due to various ecological crises, does not constitute a form of personal harm.
To prove personal harm (resulting from fear) in an environmental context, the plaintiff must establish a close connection between them and the environment. Four types of close connection can be distinguished. First, the environmental degradation can lead to a violation of the plaintiff's personal integrity. This is the most important category in practice. It encompasses cases of present physical injury, mere toxic exposure, mental injury and violation of the person based on the seriousness of a norm violation. Second, the environmental degradation can damage the plaintiff's property, which can lead to both patrimonial as well as extrapatrimonial harm. Third, the environmental problems can affect non-attributed environmental elements which are effectively used or enjoyed by the plaintiff for their own need satisfaction capacity. Last, environmental problems can bring forth a more existential loss, the loss of a meaningful bond with the environment, i.e. solastalgia.
Since the latter form of harm remains underexplored in the literature, I emphasize that it fits within the current Belgian and Dutch extracontractual liability framework. Solastalgia
Lastly, to give a full picture of the plaintiff's burden of proof in harm resulting from fear cases, I elaborate on the use of presumptions. Using a presumption, a judge can infer the existence of harm from other known facts. The technique is especially interesting considering my recognition that environmental harm resulting from fear often is a form of mass harm. Indeed, these factual presumptions can be collectivized, for which I have introduced the term collective factual presumptions. A certain set of circumstances can empower courts to legitimately infer the existence of harm for a larger group. Courts still make a factual inference, but on a collective level, considering the available scientific knowledge in a specific case. This provides a promising nuanced solution for establishing harm in cases of mass harm resulting from fear.
Chapter 4. Fear and reason
In the fourth chapter, I focus on the gap between fear and reason and its consequences on liability for harm resulting from fear. How should judges deal with cases of actual harm caused by unreasonable fear? Upon examining the case law in Belgium and the Netherlands, it becomes clear that a certain line needs to be drawn. However, the current state of the art does not provide a clear legal basis for excluding unreasonable fear, let alone a clear and consistent method for evaluating the reasonable nature of fear. I examined whether current theories of law could lay the groundwork to tackle this problem.
First, I assessed different theories of causal attribution. To what extent should a judge legally attribute the consequences of unreasonable fear to the wrongdoer who triggered that fear? Two criteria stood out as possible grounds for limiting liability. First, a judge could find that the fault of the defendant was merely a trigger for the harm resulting from reasonable fear. That means that their fault did not meaningfully increase the risk of such harm occurring, i.e. that it did not deliver a meaningful causal contribution. Second, a judge could find that the harm resulting from unreasonable fear was unforeseeable. That means that the harm resulting from unreasonable fear was a highly improbable consequence that would not have occurred in a normal scenario. Additionally, in the Netherlands, the level of knowledge and experience of the wrongdoer at the time of the fault is taken into account. However, the application of both criteria to cases of harm resulting from unreasonable fear remains difficult, not in the least because of current unclarities in the notions of causal contribution and foreseeability themselves. Additionally, these criteria could be nuanced through other factors that play a role in both the Belgian and the Dutch theories of reasonable attribution.
Moreover, I show that reasonable attribution meets its limits when the underlying fear is based on a predisposition. That term denotes all attributes of a plaintiff that leave them vulnerable to certain types of harm (resulting from fear). In principle, wrongdoers must take their victims as they find them. That rule is designed to accommodate the great diversity in our society. Young or old, strong or weak, religious or atheist,… everyone deserves full indemnification of harm unlawfully caused by another. The exceptions to this general predisposition rule leave some room for considering the potentially unreasonable nature of the fear. First, in Belgium, I believe that the principle of predisposition should be nuanced in cases of manifest unreasonability. A similar result in the Netherlands could be reached if the case law acts on the suggestion of certain authors to install an uncertainty correction to limit liability according to the degree in which it is equitable to attribute uncertainty concerning hypothetical causation to the harmed party themselves. In any case, the analysis shows that the principle of predisposition in general should be reconsidered and nuanced. The proposed corrections should not exclusively apply to harm caused by psychological predispositions. There should be no fundamental difference between psychological and physical vulnerabilities in terms of reasonability. In the end, I suggest yet another promising avenue for nuancing harm resulting from unreasonable fear. I rely on the new definition of harm in the Belgian Civil Code. Article 6.24 BCC only recognizes the harm if it flows from the violation of a legally relevant interest. Courts should consider whether the belief system upon which the fear is based is legally protected under human rights or other norms. It should take into consideration current moral societal convictions. This provides a consistent legal basis for excluding harm resulting from unreasonable fear. Of course, it merely provides a basis. It does not yet put forth a clear method for examining the reasonable nature of fear itself.
I have sought inspiration in France, California, New York and Maryland to construct a reasonable fear test. In that analysis, I found several factors that could be useful to building a Dutch and Belgian approach to reasonable fear. I propose a three-pronged approach to unreasonable fear with an exception. In principle, to establish reasonable fear, three criteria must be met: exposure, increased risk and the prospect of serious harm.
First, I discuss exposure. The plaintiff should prove that they were actually exposed to a certain danger. In cases of toxic exposure, the most convincing proof consists of medical proof of contamination. Physical manifestations, such as the pleural thickening in cases of asbestos exposure, can also provide convincing evidence. However, I would urge judges not to overmedicalize this criterion. Other objective circumstances could give a plaintiff a reasonable window for anxiety as well. In case of contact with HIV, that reasonable window consists of the period in which the plaintiff cannot definitively rule out contamination. Additionally, but contrary to New York case law, I believe that the 3.400 liters of petroleum in Cleary's basement could also count as an actual exposure to a dangerous substance. Even if medical practitioners show that the Cleary family has not been physically contaminated, the smell of gasoline in their own home could provide the family with a reasonable window for anxiety. By applying the exposure criterion in this way, I follow the Maryland Exxon Mobile case law. The plaintiff must bring forth objective and scientific evidence of exposure.
The second factor is proof of an increased risk. The Maryland Exxon Mobile case provides a valuable interpretation of the increased risk criterion. The risk must exceed the risk imposed on the general population. This criterion can be linked back to the criterion of personal harm, discussed in chapter three. Harm must always be personal, in the sense that it must be specific and more serious compared to harm suffered by the general population. By extension of that principle, harm resulting from fear must flow from a personal risk, i.e. a risk that is specific to the plaintiff and more serious compared to the general population. There is no need to set up an absolute minimum bar of likelihood of 50%. The judge merely needs to compare the situation of the plaintiff to the situation of the general population.
Third, the exposure must bring forth a prospect of serious consequences. The plaintiff should prove that the aforementioned risk relates to a rather serious form of harm. Like the French Cour de cassation, I believe that there is no need to install an explicit minimum bar of seriousness. In cases of toxic exposure, the substance should be scientifically linked to diseases. Those diseases are usually sufficiently dreadful to accept the reasonability of the fear.
This reasonable fear test serves first and foremost as a tool to limit liability from harm resulting from fear to reasonable proportions. If a judge finds the fear unreasonable, the plaintiff cannot establish liability. However, the test could also serve a secondary purpose. In the previous chapter, I concluded that judges can factually presume the existence of harm resulting from fear. The harm can be inferred from the other objective circumstances of the case. The reasonable fear test could lead to the conclusion that the objective situation of the plaintiff is so fearful that harm can be presumed. As such, the reasonable fear test can function as a basis for a factual presumption of harm, the second and third criteria in particular. On the one hand, a high risk of disease after exposure or any other type of harm could provide an argument for establishing a factual presumption of harm. On the other hand, the nature of the feared harm could also play a role. Factors such as the duration of the fear, the need for regular examination, the downward trend in the plaintiff's health or the nature of the feared worst case scenario could play a role here. In cases such as the French PIP judgment, the level of risk and the feared drastic operations are so disturbingly grave that a certain level of harm resulting from fear can be presumed. In the case of Groningen earthquakes, the repeated property harm is scientifically proven to bring about harmful levels of stress. Extrapatrimonial harm (resulting from fear) can be presumed in those cases.
These three conditions need to be fulfilled to prove reasonable fear. However, they represent a highly rational and scientific approach. In cases of predisposition, the regime can be subject to exceptions. The predisposition can consist of a personal character trait, but it can also consist of a certain belief-system. In case of the latter, the reasonable fear test must assess whether that belief-system is recognized and protected by law. To assess this, the judge must examine potential legal bases for protection and current societal moral convictions, which, admittedly, leaves a wide margin of appreciation to the judge. The New York case of Castro provides a good example. Even though Castro's fear of HIV was not rational, Castro's belief of danger was based on governmental massive informational campaigns. The government, through its fearmongering, created a societal context in which Castro's fear should be considered legally relevant, even if it is not entirely objective. Similarly, in the case of an unlawfully placed phone antenna, the past scientific concerns around phone radiance had created a legitimate
De opkomst van 'edtech brokers': onderzoek naar de opkomst van nieuwe tussenpersonen in het beleid en de praktijk van digitaal onderwijs
No full textThe goal of this doctoral dissertation is to conceptualize and empirically scrutinize educational technology brokers as a new kind of actor that mediates relationships between schools, academia, governments and industry. Edtech brokers are defined as intermediary organizations that guide schools in the procurement, adoption, and pedagogical use of edtech. Their services include the promotion of hardware (i.e., laptops, tablets, smartboards) and software (i.e., apps, platforms, data management systems), the creation of knowledge of "what works" in educational technology, and pedagogical guidance to schools in the form of workshops and training sessions.
This project investigates edtech brokers through in-depth case studies of four edtech broker organizations operating in Europe selected from a wider range of brokers identified at the outset of the project. The cases were purposefully selected to explore the multifacetdness of brokers, and to emphasize the different ways in which they operate. Through four empirical studies, this project has two main goals. The first one is to disentangle the main practices through with brokers connect traditionally differentiated spheres of public education, private edtech markets, governments, and research centers. The second one is to understand how, when performing such practices, brokers influence and transform the actors they connect. From an analytical perspective, this project stresses the embeddedness and relationality of edtech brokers in an attempt to capture their agency as emerging experts in education policy and practice.
The dissertation is comprised of four chapters, each of them addressing different layers of edtech brokerage. The first chapter is grounded on an exploration of the edtech sector and the policies about school digitization, specifically studying three cases of edtech brokers. It offers an initial conceptualization of the different types of edtech brokers, including the main ways in which they mediate between schools and the edtech market, and the most prominent education imaginaries that guide their actions. The second study explores the different ways in which brokers build evidence of "what works" for guiding schools in the usage and adoption of edtech, as well as the impact this evidence has in markets and governments. The third study focuses on how edtech brokers, through coaching and training sessions to schools, aim to encourage teachers towards the use of edtech, reconfiguring in important ways the notion of teacher professionality in a digital age. The fourth study explores edtech brokering "in action", studying how brokers' new forms of expertise operate in school, placing emphasis on how their practices are received, negotiated or even contested when they arrive in local school settings.
The concluding section offers analytical, empirical and methodological contributions to study edtech brokers, and extend an invitation to continue the empirical explorations on intermediary actors operating in education policy and practice. These actors, of which edtech brokers are an exemplary case, demand further investigations as they play an important role in defining, among other things, how schools and school systems continue to digitalize, how edtech markets gain access to school systems, and how governments enact policy reform and imaginaries into the locality of schools.status: Accepte
Shades of acceptance: Mapping public tolerance of discriminatory practices and its links with authoritarianism
No full textstatus: Publishe
Educating Our Senses in a Collective Way: Some Notes and an Experiment on Aesthetic Education
No full textstatus: Publishe
Voorbij de tweepartijenkloof: hoe coalitiedynamieken en ideologische oriëntaties affectieve polarisatie in Europa herdefiniëren
No full textAffective polarization, understood as the mutual dislike between opposing political groups, is widely viewed as a threat to democratic societies. This dissertation consists of six distinct articles which examine how this U.S.-born concept can be applied to, and operates within, Europe's multiparty context. Drawing on observational, longitudinal, and experimental data from 423,524 respondents across twenty democracies, it advances the argument that affective polarization and its consequences are heavily dependent on how political elites and citizens interact with three defining features of multiparty systems: coalition dynamics, the radical right, and ideological camps.
The first part, On Shifting Lines, focuses on the role of political elites and studies how coalition dynamics and elite signaling shape partisan affect. Articles 1-3 find that 1) elite cooperation reduces intergroup hostility only when such cooperation is perceived as successful, 2) center-right accommodation of the radical right fails to reduce affective divisions, instead simply shifting them toward the political center, and 3) when political elites do (re-)ostracize a radical party, animosity toward this party increases.
The second part, On Camps in Motion, centers on citizens themselves, highlighting the overlooked heterogeneity in political attitudes among the affectively polarized in European multiparty systems. Articles 4-6 show that 1) most citizens in Europe do not identify with one single party, but feel closer to broader ideological camps while being less affectively polarized, 2) radical-right supporters are not one homogeneous block, whereby only those who strongly dislike both the center left and center right are substantially less supportive of democracy, and 3) affective polarization in Europe often coexists with democratic support, which contradicts previous notions that affective polarization is inherently harmful to democracy.
The dissertation concludes that affective polarization in Europe cannot be understood by simply looking at the U.S., and urges away from U.S.-centric concerns about affective polarization. Coalition dynamics, the contested status of the radical right, and ideological camps jointly shape how affective boundaries are drawn and what its consequences are for democracy more broadly. In such context, citizen attitudes are highly heterogeneous and malleable, while elites can rapidly redraw affective fault lines through their performance, signaling, and gatekeeping vis-à-vis radical actors. It also cautions against treating affective polarization as uniformly harmful, highlighting its close ties to political engagement.
These findings suggest that Europe's multiparty systems contain particular levers that can channel animosity toward defending democratic norms rather than eroding them. Yet, this resilience is contingent: if elites fail to cooperate or abdicate their gatekeeping role, allowing politics to harden into a binary clash, even multiparty systems risk drifting toward a democracy in decline, as observed in the United States today or in ancient Athens over 2,400 years ago.status: Accepte
Vacuüm Gedeponeerde, Volledig Anorganische Perovskiet Fotodiodes
No full textWhen comparing modern smartphone cameras to those from the 2000s, the improvements in image quality, including resolution, low-light sensitivity, and color accuracy, are remarkable. These improvements can be partially attributed to technological advancements in the design and fabrication of CMOS image sensors, the camera component responsible for converting incoming light into electrical signals. In this context, the emergence of color-splitting nano-photonic structures as an alternative to conventional color filter arrays marks a promising advancement that may accelerate the continuous scaling of pixel pitch in image sensors.
Nevertheless, the continuous reduction of pixel pitch has the adverse effect of increased optical and electrical crosstalk, exacerbated by the low absorption coefficient of silicon, which is used as the photoconverting material. For this reason, thin-film photodetectors emerge as a promising alternative. Having an absorption coefficient that is nearly one order of magnitude higher than that of silicon in the visible spectrum, thin-film photodetectors enable comparable photon absorption within just a few hundred nanometers of thickness. Taking into account the requirements for high response speed and compatibility with high-temperature semiconductor fabrication processes, inorganic metal halide perovskites are selected as a suitable candidate. Additional requirements for scalable fabrication motivate the use of the vacuum thermal evaporation as the perovskite deposition approach. Even though solution-processed, hybrid organic-inorganic perovskites have been extensively investigated over the past 15 years in the context of solar cell applications, the development of all-inorganic and solely vacuum deposited perovskite photodiodes remains elusive. This observation was the main motivation of the present work, which has been approached from three different perspectives.
First, a comprehensive characterization of thermally co-evaporated CsPbI2Br thin films is conducted. Special emphasis is given on investigating the impact of the post-deposition thermal annealing step, whose real-time effect is studied by means of temperature-dependent spectroscopic ellipsometry. The latter is demonstrated to be an accessible, reliable, and low-cost approach to gain insights not only on the film's optical constants, but also its temperature-dependent expansion, roughness increase, and phase evolution.
Second, the CsPbI2Br layer is integrated into a vacuum-deposited and all-inorganic photodiode structure. The choice of the electron transport layer (ETL) is revealed to be critical for the diodes' reverse bias stability, performance variability, and response speed. Eventually, the adoption of an ETL that consists of a fullerene and a metal oxide bi-layer, along with the careful tuning of the respective thicknesses, leads to a threefold optimization, through a minimization of interface defects, an elimination of shunt pathways, and a reduction of the diode's RC constant.
Third, a high-throughput experimentation approach is introduced to investigate the ambient phase stability of CsPbI2Br thin films and overcome challenges related to extreme batch-to-batch or even within-batch variations. We show that by depositing a broad compositional gradient of the perovskite across a 6'' wafer, the optimal range of precursor molar ratios can be identified, significantly enhancing the films' ambient stability from a few hours to several months.status: Accepte