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Testing halo mass functions and heavy seed formation pathways in the high-redshift Universe
Full text linkWe investigate the high-redshift (z ≥ 10) Universe i.e. when it was < 1 Gyr
old. We focus our investigation in two main areas: the distribution of dark
matter (DM) halos and the formation of intermediate-mass (M ∼ 103 − 105 M⊙)
black holes (IMBHs). We examine the abundance of DM halos as a function of
redshift and mass using N-body simulations. We also analyse the influence of
both Lyman-Werner (LW) radiation and metal enrichment on the number density
of IMBHs using analytic models and by post-processing simulation data.
We first review the state of the field today by discussing the fundamentals
of Λ-Cold Dark Matter (ΛCDM), DM clustering on both small and large scales,
quasars and the supermassive black holes (SMBHs) that power them. We also
detail how data from the James Webb Space Telescope (JWST) have prompted
us to question the origins of SMBHs and have shown us how different the high-z
Universe is from the local one (z ∼ 0). Finally, we describe the computational
tools employed in our investigations.
Next we use the adaptive mesh-refinement code Enzo and the N-body smoothed
particle hydrodynamics code SWIFT to compare (semi-)analytic DM halo mass
functions against the results of direct N-body models at high redshift. Our goal is
to investigate if these fitting functions could be a source of error when comparing
JWST data to cosmological models.
Next we compare the number density of IMBHs informed by an analytic model
accounting for LW radiation and metal pollution with one informed by simulation
results from Renaissance. This is a high-resolution simulation suite with the
purpose of probing the high-z Universe. Our goal is to determine if recent JWST
observations could be accounted for by this heavy seed formation pathway alone.
We also compare this channel against other recent models in the literature.
Finally, we summarise our aims, methodology, conclusions and we briefly
discuss how this work could be expanded upon in future. In §2, we find that
the difference between direct N-body calculations and (semi-)analytic halo mass
function fits is generally < a factor of 2 (at z ∼ 10) within the mass range of
galaxies currently being observed by JWST, and is therefore not a dominant
source of error when comparing theory and observation at high redshift. In §3,
we find the highest number densities (nheavy seed host ∼ 10−4 comoving Mpc−3 at
z ∼ 10) are still too low for this channel to be the dominant formation pathway for
heavy seeds when compared to JWST observations, especially when considering
the growth requirements and duty cycle of active galactic nuclei (AGNs) necessary.
This channel can at best be responsible for only a small subset of high-z AGNs
while other models from the literature (e.g. rapid assembly) are more promising
to explain JWST observations at high redshift
The European Union at Sea: A Historical and Geopolitical Analysis of the European Union’s Maritime Operations and Their Impact on Maritime Governance and Security, 2008-2024.
No full textThis doctoral thesis explores the European Union’s (EU) maritime security, which is
recognised as a crucial European security area and a vibrant field within current academic
discourse in Irish and European contexts.
This first part of this thesis is divided into three different chapters. Firstly, Chapter 1
examines the academic, institutional, and industry definitions of maritime security and
maritime security operations, before providing its own definition on the latter concept,
and provides a critical review of traditional and contemporary scholarly works on
maritime security, naval strategy, and maritime strategy, particularly since the topic made
it to the headlines globally in 2008 off the coast of Somalia. Secondly, Chapter 2 provides
a historical analysis of the EU’s common foreign, security, and defence policy from the
failed project of the European Defence Community in 1954 to the 2009 Lisbon Treaty,
and analyses the various actors involved in the decision-making of European security and
defence policies. Thirdly, Chapter 3 describes the decision-making process of the CSDP’s
military missions, examines the EU’s strategic thinking in the realm of maritime security
since the 2003 European Security Strategy until the 2023 second edition of the Maritime
Security Strategy and, ultimately, provides an overview of the four naval missions
launched, as of June 2025, in the framework of the CSDP which will be explored in depth
in the subsequent case studies.
The development of the EU’s maritime security, from the inaugural 2008 operation
"Atalanta" to the most recent, "Aspides", is at the core of this research, and its analysis
was conducted through a comprehensive multi-methods approach, investigating maritime
security governance. The second part of the thesis analyses twenty different case studies
across six chapters. Chapter 4 presents an overview of security and defence policies and
maritime security operations of a number of Northern European countries, while Chapter
5 explores a peculiar case study in the same region, Ireland. Subsequently, Chapter 6
examines Germany in the Central European geographical area, while Chapter 7 moves to
the Eastern Mediterranean Sea with the analysis of Croatia, the Republic of Cyprus,
Greece, and Turkey. Then, Chapter 8 focuses on the two Central Mediterranean countries,
Italy and Malta, and Chapter 9 investigates two Western Mediterranean states, France and
Spain. The “Epilogue” follows in Chapter 10 with Operation Prosperity Guardian and
Operation Aspides, before the thesis draws together the relevant conclusions in the final
Chapter.
To conduct this investigation, documents, articles, official sources, and national strategies
in seventeen languages were analysed, together with forty-six elite interviews with
military personnel, policymakers, diplomats, and civil servants. This has entailed
historical, geopolitical, and strategic analysis aimed at understanding the rationales
behind EU maritime operations, their conduct, and the strategic postures of the various
EU member states.
The research concludes that geography, spatial proximity to threats, and the availability
of resources were, as foreseen, critical in shaping the strategic priorities of most member
states. However, strategic cultures and ideological stances, like military neutrality, played
an even more important role in revealing how national interests aligned or, even more
importantly, diverged within the EU
Data debates in urban development: The data politics of facts and counter-facts
Full text linkData relating to urban development are often accepted and used at face value, treated as impartial, objective, incontrovertible facts. However, the validity and veracity of official datasets can be challenged, with a data debate forming between actors, which might include the provision of alternative datasets and counter-facts. Such data debates can be significant as they undermine confidence and trust in datasets, which in turn can have knowledge, policy, market and political effects. This paper examines the nature of such data debates by examining two long-running disputes in Ireland concerning the veracity of residential vacancy and housing completions data
Rediscovering the Boundaries of Pure Reason: An Archaeology of Kant’s Critical Phenomenology
Full text linkThe investigation presented here is a return to the “island” of reason which Immanuel Kant
mapped long ago [B295]. Kant uses the metaphor of an island for reason’s dwelling place because
his central claim is that there are limits, or shores, beyond which reason cannot go. In what follows
I will try to retrace Kant’s steps in surveying the island of reason, arguing that the boundaries of
reason he discovered take two distinct forms: one which is at the level of the phenomenological
object, which I will call the ‘ontological’ limit, and another which is at the level of our universal or
public use of language about objects, which I will call the ‘semiotic’ limit. Both limits are brought
into being by the possibility, and the formal structure, of knowing the bare outside of our own finite
activity: namely, the indeterminable unconditioned. Importantly, for Kant we do so from within that
bounded space, not from without. It is knowing that there is something which we cannot, on
principle, fully grasp which establishes the “boundaries” of finite human reason
Rewriting the Self: From the Courtroom to the Classroom’ ‘Exploring Identity and Transformation Through Autoethnography and Shared Experience
Full text linkThis thesis explores how adult identity is shaped and reshaped through experiences of transformative learning. It combines two approaches: an autoethnographic account of my own journey from law to education, and six semi-structured interviews with participants who have also navigated significant personal and professional change.
The research is grounded in an interpretivist framework, which views reality as constructed through lived experience and meaning making. Narrative inquiry was used to capture participants’ stories in depth, while thematic analysis provided a systematic way of identifying patterns across the data.
The study participants, three women and three men, aged between their mid-thirties and mid-sixties, reflected varied personal backgrounds but shared experiences of negotiating identity shifts through education and professional life. Their stories revealed the challenges of self-doubt and feelings of not belonging, balanced with personal and professional roles, along with the opportunities education offered for renewal and growth.
The findings highlight that identity transformation and self-rediscovery are not a straightforward or uniform process. Instead, it is complex, fluid, and shaped by both personal history and wider cultural expectations. While some participants described disruption and uncertainty, others expressed confidence and belonging. My own reflections often resonated with their accounts but equally showed the diversity of pathways through which adults reconfigure their sense of self.
The study concludes that adult education plays a vital role not only in developing knowledge and skills but also in providing a space for reflection, rediscovery, and identity reconstruction. By situating both personal and participant narratives within wider cultural contexts, this thesis contributes to understanding how adults navigate the ongoing task of becoming and belonging
Bayesian Statistical Machine Learning Models for Predicting Multivariate Data with Non-Ignorable Partial Missingness
Full text linkMissing data is a pervasive challenge in statistical modelling, particularly in multivariate
response settings where partial missingness leads to complex, overlapping missingness
patterns. Standard methods often rely on strong and unrealistic ignorability assumptions,
such as missing completely at random (MCAR) or missing at random (MAR), typically
employing complete-case analysis or imputation, leading to inefficiencies and biases. This
thesis introduces three novel Bayesian joint models, integrating the selection model framework
with Bayesian additive regression trees (BART) to provide a flexible, non-parametric
solution for handling non-ignorable partial missingness in multivariate data.
The motivation for these models arises from limitations of standard missing data techniques,
as exemplified by the global Amax dataset which exhibits substantial, overlapping
missingness in the response variables. Original methods applied to this dataset implicitly
assume ignorability, leading to biased inferences and loss of information. To address this,
our novel models jointly estimate both the response and missingness processes, enabling
the recovery of non-ignorable missing not at random (MNAR) mechanisms, in addition to
MCAR and MAR. These models also extend to settings with partially observed covariates
with ignorable missingness.
By leveraging BART’s ability to flexibly model complex, non-linear relationships, we
adopt a multivariate BART framework to capture dependencies across responses while
maintaining predictive flexibility. For the missingness mechanism, we explore both parametric
and non-parametric Bayesian approaches. The probit regression model allows for
the incorporation of prior information on the missingness mechanism, offering greater
interpretability when domain knowledge is available. In contrast, the probit extension
of BART allows for automatic variable selection and flexibly models complex interactions.
Additionally, we adopt a seemingly unrelated framework to model dependencies
across responses while allowing dynamic response-covariate relationships. These methods
are evaluated through extensive simulations and applied to the global Amax dataset,
demonstrating strong performance in identifying non-ignorable missingness structures and
recovering unobserved values
Kierkegaard's Objections to Natural Theology: Their Significance and Priority in his Development of Post-Kantian Philosophy of Religion
Full text linkAs a philosopher, Kierkegaard is often either hailed or condemned for opposing reason to personal religious Christian faith and is probably most renowned for his declaration that 'faith begins where thought leaves off'; but Kierkegaard, as a man of intelligence, has to begin with and take on thought, in particular the thought that thinks that one can know that God exists, whether one is a religious believer or not. For Kierkegaard, therefore, the very thinking through of the philosophical implications of his own personal religious faith and of those who argue for the knowability of the existence of God are inextricably linked and integral to his conception of philosophy as rigorous unscientific religious thought. For his critics, such as Heidegger, and many like him, one can be either a thinker or a religious believer; but Kierkegaard is, par excellence, a religious thinker. This paper, therefore, examines Kierkegaard's religious thinking on its own terms, that is to say, as taking on and dealing with arguments for the existence of God which he found, before and after Kant, in the tradition of philosophical thinking, and which required him to develop new lines of thinking in philosophy in general and in post-Kantian philosophy of religion in particular
Complex PTSD and identification with the aggressor among survivors of childhood abuse
Full text linkChildhood abuse (CA) is a risk factor for trauma-related disorders including posttraumatic stress disorder (PTSD) and complex posttraumatic stress disorder (CPTSD). This severe form of interpersonal trauma may result in “identification with the aggressor” (IWA), in which the individual may take on the beliefs, perspectives, and behaviors of the perpetrator. Although previous evidence suggests that IWA may be particularly related to CPTSD as compared to PTSD, there has been no study that investigated this hypothesis.
Objective
The current study explored the relations between IWA and PTSD and CPTSD symptoms, and the contribution of IWA to the excess probability of PTSD and CPTSD classifications, as compared to no classification.
Participants and setting
This cross-sectional study was conducted among 320 Israeli adult CA survivors aged 21–63 (M = 42.04, SD = 10.81).
Methods
An online survey was completed by a convenience sample of adult CA survivors.
Results
Replacing one's agency with that of the perpetrator as part of IWA had a significant effect on both PTSD and CPTSD symptoms (ES = 0.36 and 0.24, respectively), and served as a risk factor for both PTSD and CPTSD classifications. Moreover, analysis of the models' predicted values reveals that the predicted probability of CPTSD classification was 3 to 5 times higher than on the probability of PTSD classifications, for low to high values of the replacing one's agency scale, respectively.
Conclusions
The current findings suggest that IWA may describe some of the deep and long-lasting detriments of CA on self, and may contribute to the development of CPTSD symptoms
What is Human Dignity? An Application of Edith Stein's Phenomenology
Full text linkEdith Stein did write a few comments on human dignity, but nothing that amounts to a thorough analysis. The idea was formulated explicitly as the foundation of the Human Rights Tradition after the Second World War, and as such it would no doubt have interested her greatly. The drafters of the declaration of human rights deliberately refrained from appealing to an agreement about the philosophical foundation of the idea, since UNESCO advised it might not be possible to find a solution all could accept. In Stein’s spirit of conciliation of different traditions, however, and with the aid of her phenomenology, we can propose to understand it phenomenologically as the fundamental value of the human being, entitling it to respect. In this paper I detail how it comes about that we with quasi-necessity identify human dignity in this way by deploying a phenomenological analysis as Stein taking Stein’s analyses as its model
An Exploration of Trust in Human-Robot Interaction: From Measurement to Repair Strategies and Design Principles
Full text linkThis paper presents an interdisciplinary scoping review of literature on trust and
trust repair in human-robot interaction (HRI), focusing on social and service robots. The primary
aim is to provide a comprehensive analysis of trust in social robotics and the methodologies for
measuring trust within HRI. Distinct from prior reviews, this work delves into both trust models
and trust measurement methods highlighting the complex nature of trust. This study assesses trust
repair strategies, including promises and explanations, in different contexts. It also investigates
scenarios of compromised trust and explores both communicative and proactive repair approaches. Finally, the paper presents nine key design principles such as safety, transparency,
apology mechanism etc., derived from the reviewed literature, as guidelines for the development
of social and service robots. These principles provide researchers with a path for creating robots
that can build and maintain trust, particularly when they are making mistakes and need to correct
them