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Weak lensing: applications in gravitational wave and galaxy cluster cosmology
Radiation travelling through the Universe is weakly lensed by Large Scale Structure.
Measurements of this effect are a valuable probe of the content and dynamics of the
Universe. In this thesis I will explore novel applications for the weak lensing of both
gravitational and electromagnetic radiation.
Future gravitational wave (GW) detectors will observe tens of thousands of merging
black hole or neutron star binaries through their gravitational radiation. Weak lensing
will be the dominant source of uncertainty when using these sources as standard sirens:
measuring their distance−redshift relation to probe the geometry of the Universe. I
performed a detailed study into the impact of weak lensing on standard siren analyses,
finding it to be significant, and demonstrating that current mitigation tactics require
improvement. I have also developed new approaches to reducing the impact of weak
lensing. Besides being a source of uncertainty, the weak lensing of gravitational waves
also contains cosmological information. Using a combination of future GW detectors,
the vast number of observations will be sufficient for a statisticalweak lensing analysis—
using the weak lensing effect on GWs over the sky to probe structure formation. I have
demonstrated the strength of this method, finding several novel applications such as
constraining the sum of neutrino masses.
The distortion of light from background galaxies around foreground galaxy clusters
allows inference of the cluster density profile, the shape of which is sensitive to
properties of structure formation. Comparing cluster profiles in the so-called infall
region with predictions from a suite of cosmological simulations allows constraints
on cosmological parameters. These constraints exhibit an orthogonal degeneracy to
those from other standard tests, such as cluster abundances or cosmic shear, making the
infall region a promising complementary probe. I have pioneered this novel test, and
performed a first-of-its-kind analysis using weak lensing data from the Ultraviolet Near
Infrared Optical Northern Survey, combined with a publicly available galaxy cluster
catalogue, obtaining constraints of Ωm = 0.29 ± 0.05 and �8 = 0.80 ± 0.04
Leveller social networks and their sectarian dynamic: 1646-1658
This thesis re-examines the so-called ‘Levellers’ of the English Revolutionary period alongside concurrent sectarian activity. The period under examination is the years 1646 to 1658, commencing with the gradual emergence of Leveller rhetoric from within London’s tolerationist discourse, and ending with the death of Oliver Cromwell in 1658, which commenced a period of recalibration and unrest across the Protectorate. The thesis argues that there was very little of what could be considered a distinct political Leveller movement, as previous scholarship has suggested, rather that Leveller networks and discourse existed within sectarian circles across the nation. It is argued that the nature of Leveller activity was far more dependent on a godly belief system and discourse within sectarian congregations than has previously been acknowledged. Rather than the traditional Leveller leadership, this work foregrounds sectarian preachers and polemicists, and it is argued that the Leveller platform was dependent on preachers and congregational circles as its primary means of development. Individuals such as Samual Oates, Samuel Chidley, Samuel Hyland and Jeremiah Ives are presented along with others as lay-preachers who were crucial nodes for driving Leveller activity.
The thesis suggests that a Christian underpinning of Leveller beliefs, such as Right Reason, or an emphasis on godly righteousness, have been overlooked in previous scholarship and that these are further signals of a fundamentally Christian foundation to Leveller arguments. While a Reformed two-kingdoms theory, the separation of the civil and spiritual state, was at the heart of Leveller campaigns, issues of a democratic legislature rarely featured. This thesis demonstrates that Leveller arguments which were found in both civilian and military circles often employed a millenarian position, relating to the anticipated Second Coming, and much of their Christian belief informed their desires for an egalitarian and tolerationist civil government. This thesis will utilise the language of social networks in their informal exploration, suggesting that Levellersim is best understood as moving through a series of interwoven networks, rather than a coherent and organised movement. A social network vocabulary is utilised to assist in the understanding of Leveller social connections and the ways in which Leveller arguments were transmitted among godly congregations and social affiliations. After re-examining the period of Leveller activity most discussed in previous scholarship, the period 1646 to 1649, the thesis continues its analysis of ongoing sectarian Leveller activity into the Commonwealth and Protectorate years. This thesis concludes by examining the presence of Leveller arguments and social networks within Fifth Monarchist congregations, suggesting that the two persuasions need not have always been mutually exclusive. Some ministers and polemicists within the Fifth Monarchy community, including John Rogers, Samuel Hyland and James Frese did promote Leveller ideas as a godly position in preparation for the rule of Christ’s directly appointed Saints
A holistic kinetic model for the hydrothermal carbonisation of lignocellulosic biomass
This research presents the first holistic kinetic model for hydrothermal carbonisation (HTC) of lignocellulosic biomass, based on the composition of cellulose, hemicellulose, and lignin. The model predicts product outcomes for hydrochar, gas and liquid residuals over a wide range of processing conditions: temperatures (200 – 260 °C), residence times (0 – 12 hours), and biomass-to-water ratios (1:4 to 1:50). Individual kinetic models for the macromolecular compounds were developed and validated with experimental data. The combination into a holistic model demonstrated accurate predictions of the solid phase (hydrochar), where 258 data points from 58 lignocellulosic biomass sources (49 different types, from 41 studies including this one) were processed. The accuracy of the holistic kinetic model was improved when considering the interaction effects between the macromolecular compounds in lignocellulosic biomass and by determining optimised distribution factors for the non-macromolecular fraction into the solid, liquid and gas phases. The finalised R^2 value for hydrochar was 0.966. Prediction of the gas phase was evaluated and a correlation determined, however, further developments with more experimental quantification of this phase is necessary to improve prediction capabilities, with the final model resulting in an R^2 of 0.120 for this phase. The finalised holistic kinetic model shows promise for predicting the hydrochar produced from several non-traditional lignocellulosic biomass types, presenting an advanced future application of this research
Optimising methodological practices within psychology: a parapsychology case-study
Parapsychology is a contentious research field within psychology. One of the most
active research areas is the investigation of the psi hypothesis using the experimental
paradigm known as the psi ganzfeld. The psi ganzfeld is a form of mild sensory deprivation,
during which participants attempt to perceive a randomly chosen video or image target. The
participant is tasked with becoming aware of a target, which may be shown in a different
location with no one watching (clairvoyance design), someone watching it in a different
location (telepathy design), or the target is chosen after the participant makes their decision
(precognition design). During the ganzfeld, participants are asked to vocalise any
impressions, sensations, and experiences, which are often audio recorded and are known as
the mentation. After the session, participants rate which video or image clip most closely
matches their experience. If the participant’s top choice matches the target clip, the session is
considered a "hit." However, due to the contentious nature of this experiment, the psi
ganzfeld is an ideal case for demonstrating current methodological weaknesses and proposing
recommendations that can improve research practices more broadly.
This thesis is structured around two overarching themes: the first theme deals with
broader methodological issues in psychological research, using the psi ganzfeld experiment as
a case study. It discusses the replication crisis in psychology, situating parapsychology within
this context, and explores the methodological and statistical challenges common to both
fields, such as questionable research practices and the limitations of meta-analyses. A critical
examination of meta-analyses of the psi ganzfeld is provided, highlighting how different
methodological decisions regarding study inclusion influence the outcomes of literature
reviews. An alternative approach to conventional meta-analyses is also presented,
demonstrating how to triangulate and synthesise contradictory results from multiple meta-analyses to achieve a more comprehensive understanding of research decisions and study
outcomes.
The second theme of the thesis focuses on methodological improvements specific to
parapsychology, which can also benefit the broader field of psychology. Experimental data
from a precognition study demonstrates the flexibility in constructing statistical analyses, via
specification curve analysis. Further, verbal reports from ganzfeld precognition studies are
analysed using a novel quantitative language analysis, offering new insights into a previously
under-examined data source in parapsychology. By applying novel methods to secondary
data, these chapters provide a more comprehensive understanding of the data. Given the
controversy surrounding the psi ganzfeld task, one of the empirical chapters addresses
methodological concerns by proposing an innovative approach to validating study software—
an aspect not commonly addressed in either parapsychological or psychological research. The
last chapter presents a meta-regression of psi telepathy studies, examining the impact of
various methodological features on study outcomes, and offering fresh insights into over 35
years of research.
Overall, this thesis highlights the ongoing methodological challenges in psychology,
even after the replication crisis produced numerous improvements and recommendations. By
using the psi ganzfeld as a case study, it underscores the need for greater transparency
regarding researchers’ degrees of freedom when designing reviews, synthesising divergent
meta-analyses through innovative approaches like multiverse meta-analyses and employing
novel methods to gain deeper insights into existing data. The recommendations and examples
drawn from parapsychology, despite its contentious nature, have broader implications for
advancing methodological rigour in psychology as a whole
Quantifying Livestock Diet Composition Using Earth Observation (EO) Data for Improved Estimation of Enteric Methane Emissions in Kenya
Poster presented at the Living Planet Symposium, Vienna, 23-25 June 2025.Livestock directly contribute to greenhouse gas emissions, mainly through enteric fermentation and to a lesser extent manure management. Livestock feed composition plays a crucial role in diet quality and the resulting emissions from livestock. However, spatio-temporal variations in diet composition, particularly in tropical environments, remain underexplored. Furthermore, comprehensive livestock diet composition datasets, essential for accurate enteric methane emission estimation, are often lacking in developing countries. Existing datasets from global studies are highly generalised and are based on expert knowledge (Herrero et al., 2013). Other studies undertaken on livestock diet composition have often been done on a local basis (Goopy et al., 2018; Ndung’u et al., 2018; Onyango et al., 2018; Wilkes et al., 2020), with less attention on country-wide studies that can provide detailed assessment and evidence of the impact of livestock diet on greenhouse gas emissions from livestock at national or regional level. For both global and local studies, they often offer incomplete representations of livestock diet composition at best, especially in regions with diverse and poorly documented livestock feeding practices. Where data is available, it has uncertainties resulting from data collection challenges and the assumption of a constant annual distribution of diet composition (MacLeod et al., 2018). This gap in accurate data is particularly problematic in developing countries, where feed composition changes during periods of feed scarcity and plenty (Mutua et al., 2023), and this is seldom captured in existing datasets. In this study, we use freely available Earth Observation (EO) data to generate spatially and temporally explicit livestock diet composition and quality data. Our approach involves three key stages. First, we identify the length of growing period (start and end of wet and dry seasons) at a pixel level using a water balance model that incorporates climate and soil property data to calculate the ratio of actual to potential evapotranspiration (Jones & Thornton, 2009). Second, we determine the feed items available to livestock during these seasons through an extensive literature review and estimate their quantities using EO data including land cover/cover fraction (Buchhorn et al., 2020) and above-ground dry matter productivity from the Copernicus programme (Copernicus, 2024), crop harvest area from FEAST global data repository (ILRI, 2022), length of growing period and crop specific indices and parameters. Third, we calculate the proportion of each feed item in livestock diets at a pixel level to derive diet composition and quality data. Finally, the results are then aggregated by livestock production systems, that are specific to Kenya (Robinson et al., 2018), providing a detailed understanding of livestock diet composition patterns in Kenya. Results indicate that livestock diet composition varied between seasons and livestock production systems. Natural grass was the dominant diet component across all seasons and livestock production systems, with the highest proportion in the diet during the long wet season (41.5%). Concentrates formed the lowest proportion in the diet ranging from 0.9 to 4.7% across seasons and livestock production systems. Diet quality as well varied between seasons and livestock production systems but was in a narrow range (55.4–62.3% dry matter; DM), which was greater than the default digestibility value of 55.0% set by the Intergovernmental Panel on Climate Change (IPCC) for livestock production systems in the region. Notably, mixed rainfed arid systems exhibited lower diet quality across all seasons. Livestock diet quality estimation using EO data demonstrated moderate to high accuracy (R² = 0.50–0.89; RMSE = 1.14–38.44% DM). These findings provide a robust basis for incorporating spatially-and-temporally explicit diet composition and quality data into life cycle assessment (LCA) models to improve GHG emission estimates from the livestock sector. Enhanced accuracy of these models can inform national-level strategies for mitigating emissions and promoting sustainable livestock production
Robust spatial perception with 4D radar for mobile autonomy
Mobile autonomous systems, such as self-driving cars, field robots, and drones, have made significant progress in recent years, with the potential to transform domains like transportation, logistics, inspection, and disaster response. However, achieving reliable and generalizable mobile autonomy in complex, real-world environments remains a major challenge. A fundamental prerequisite for realizing mobile autonomy is robust spatial perception, namely the ability to interpret the surrounding environment accurately and to localise the ego-agent precisely across a variety of complex scenarios. Conventional spatial perception approaches, largely dependent on optical sensors such as cameras and LiDARs, are compromised under adverse weather conditions or in poor lighting. This vulnerability not only poses safety concerns but also impedes the long-term, large-scale deployment of mobile autonomous agents. By contrast, 4D radar, with its resilience to challenging weather, cost-effectiveness, inherent velocity
measurements, and privacy-preserving characteristics, presents a promising alternative. Nevertheless, fully capitalising on its potential remains a significant challenge, owing to the sensor’s unique data characteristics and the absence of a well-established research infrastructure.
Against this backdrop, the present thesis systematically investigates 4D radar-based spatial perception across three pivotal tasks: scene flow estimation, moving object detection and tracking, and 3D occupancy prediction. To address sensor-specific constraints and the intricacies inherent in each task, we propose bespoke 4D radar-based methods. First, we introduce self-supervised and cross-modal supervised learning frameworks for scene flow estimation, targeting issues of data sparsity, noise, and the lack of point-wise scene flow annotations. Our self-supervised approach, RaFlow adopts novel architectures and loss functions to facilitate label-free estimation, while our cross-modal technique CMFlow, leverages cues extracted from other sensor modalities (e.g., LiDAR and cameras) to enhance performance further. Crucially, the estimated scene flow underpins downstream tasks such as motion segmentation and ego-motion
estimation. Next, we present RaTrack, a novel 4D radar-centric method for moving object detection and tracking. In contrast to traditional approaches reliant on object classification and 3D bounding boxes, RaTrack emphasises motion segmentation and clustering for improved robustness against noise and point sparsity. Lastly, for 3D occupancy prediction, we advocate the use of 4D radar tensors (4DRTs) instead of point clouds, preserving critical information ordinarily lost during point cloud generation. Our method RadarOcc, introduces an efficient pipeline capable of handling large, noisy 4D radar data while mitigating interpolation errors arising from direct coordinate transformations.
Extensive experiments on multiple real-world datasets confirm that our methods
achieve competitive or superior performance compared to state-of-the-art techniques. In the scene flow task, they surpass LiDAR-based approaches via radar-specific designs and outperform fully supervised models when sufficient unannotated data is incorporated during training. For moving object detection and tracking, our approach significantly outperforms existing tracking-by-detection paradigms, offering enhanced accuracy in tracking moving objects. As for 3D occupancy prediction, our pipeline achieves leading results among radar-based methods and demonstrates strong competitiveness relative to LiDAR- and camera-based alternatives. Collectively, these findings highlight the potential of 4D radar not just as a supplement but as a primary sensing modality for
robust spatial perception. Nonetheless, this thesis acknowledges current limitations, both task-specific and systemic, and outlines prospective directions to further advance this emerging field
The quill and the brush: Michael Boym’s collaborative translation in the Southern Ming dynasty (1644-1662)
This thesis uncovers the contributions of individuals and technologiestradiAonally
overlooked in the process of Jesuits’ cross-cultural translation and communication,
focusing on the visual works of Michael Boym (ca. 1612–1659). While recent
scholarship has increasingly focused on collaboraAons between Jesuits and Chinese
literati through textual analysis, the collaborative nature and conditions of production
of Jesuits’ visual works remains underexplored. This study fills this gap by examining
the materials, tools and techniques used in Boym’s Magni Catay (ca. 1652–1656) and
Flora Sinensis (1656). Through an analysis of these visual works, which were created
within Boym’s political and religious network—including the Southern Ming court and
the Society of Jesus—this thesis highlights the foundational roles of Boym’s
collaborators, particularly the Chinese general Zheng Sanxing 鄭三省, Viennese
publisher Matthaeus Rickhes, and other unnamed Chinese and European contributors.
Their collective efforts and technological means significantly shaped the outcomes of
cross-cultural translation and communication, offering new insights into the
collaborative processes behind Jesuit visual production.
The first three chapters examine Magni Catay, focusing on its illustrations,
handwriting, and grids. This analysis reveals a dynamic collaboration between Boym
and his associates, challenging the hierarchical authorship typically associated with
Jesuit works. The subsequent chapters explore the creation of Flora Sinensis within a
European network, emphasising how the shared religious and political interests of
Boym and Rickhes influenced the intaglio prints. Furthermore, it investigates how
Viennese printmakers and colourists adapted visual models to their personal
preferences and technological constraints, demonstrating how these processes
impacted visual details and shaped early modern cultural translation. Overall, this
study offers a novel synthesis of Boym’s manuscripts and prints, underscoring the
crucial roles of marginalised figures in early modern cultural exchange. By focusing on
materials, tools, and technology, it provides fresh insights into cross-cultural
translaAon and deepens our understanding of Southern Ming history
The syntactic representation and processing of transitives in bilinguals: evidence from structural priming in Mandarin-English speakers
This thesis discusses central focuses concerning language processing. Specifically, it discovers questions about how people represent and process transitive sentences (e.g., an active sentence, such as the dog bit the man and passive sentence, such as the rat was chased by the cat), by exploring both production and comprehension in structural priming paradigms (a fact that people tend to replicate the linguistic patterns they have recently encountered and an approach to the nature of linguistic representation), and investigating through the differences between native and non-native language. This thesis seeks to unpack the layers of how transitive sentences are syntactically represented. Central to this exploration is a deep dive into the interplay between syntax and the lexicon, emphasising the relationship of syntactic information and open- and closed-class elements, and how these syntactic and semantic representations interact to arrive at an interpretation during comprehension (i.e., syntactic representation is independent or in conjunction with semantic information).
In Chapter 2, this thesis explores the shared representation of voice among Mandarin-English bilinguals. Numerous studies suggest that bilinguals process a shared syntactic representation. However, the extent to which they integrate their two languages remains a subject of investigation. To address this question, Chapter 2 presents a series of structural priming experiments to examine whether bilingual speakers have shared representation in passive voice, and the relationship between passive voice and lexical items, explicitly focusing on Mandarin-English speakers. Mandarin-English participants first listened to a sentence (the prime sentence) that could be either active or passive. Then, they described a picture depicting a transitive event. The cross-linguistic findings suggest that Mandarin-English bilinguals maintain a shared representation of passive voice independent of lexical repetition despite differences in word order. Interestingly, the varying priming effects between priming from two different types of passive voice with different function words indicate an association between function words and specific languages.
In Chapter 3, this thesis focuses on how people decide on a final interpretation of an implausible sentence. People sometimes misinterpret (nonliterally interpret) such sentences.
They might either syntactically reanalyse or semantically interpret this sentence for the final misinterpretation. For example, people may adjust the original syntactic representation, or semantically reinterpret the sentence by directly swapping the thematic roles. The evidence for how people syntactically analyse an implausible sentence is mixed. Three structural priming experiments were conducted in transitive structures to investigate the processing of a nonliteral interpretation for an implausible transitive sentence. Chapter 3 reported results that participants were more likely to nonliterally interpret a sentence after an implausible prime than a plausible prime, which suggests plausibility information affects comprehension. Importantly, the finding is different from syntactic reanalysis. Equivalent priming after implausible and plausible sentences suggests that people are more likely to maintain their initial syntactic representation rather than to change it. In conclusion, interpreting implausible sentences relies on syntactic analysis, but people may sometimes syntactically reanalyse the initial interpretation.
Furthermore, some researchers suggest that non-native speakers rely more on non-syntactic information than syntactic information. A structural priming experiment was carried out similarly to Chapter 3 to investigate the processing of an English implausible transitive structure in Mandarin-English speakers. Chapter 4 shows that participants were more likely to nonliterally interpret a sentence after an implausible prime than a plausible prime, which suggests plausibility information affects comprehension in non-native speakers. The effect of plausibility on nonliteral interpretations is stronger in passive sentences compared to active sentences, suggesting the interaction between syntactic and semantic representation. Equivalent priming between implausible and plausible sentences suggests that non-natives tend to preserve an initial syntactic representation of an implausible passive sentence rather than overwrite its syntactic representation. The comparison between non-native and native speakers shows no differences in syntactical processing.
Together, these results update a shared syntactic representation model in bilinguals and refresh an account for nonliteral interpretation processing in both native and non-native speakers
Public participation for Disaster Risk Reduction (DRR) in Nepal: gaps between rhetoric and practice
There is a growing impetus of public participation in Disaster Risk Reduction (DRR), justified in claims that it helps in a better understanding of risks and vulnerabilities, and that by involving the common needs of communities, shared challenges and opportunities may be identified, which may be translated into improved outcomes and policy decisions. However, research-based evidence about what participation for DRR entails, the specific processes, who shapes it, and the outcome it generates is limited. This gap warrants increased attention to practice and exploration of whether and how participatory claims manifest on the ground. In a similar vein, participation cannot be viewed in isolation from the wider socio-political environment in which it unfolds. It is also important to understand the policy environment and the institutional context in which participation unfolds. Therefore, this research critically explores participation in a policy-practice interface using a Policy Arrangement Approach (PAA) examining four dimensions with Nepal as a case study: (1) actors involved, (2) the policy discourse, (3) division of resources between actors that might lead to differences in power and influence and (4) rules of the game, either in terms of formal procedures or as informal rules and ‘routines’ of interaction. The qualitative research approach includes a policy review and key informant interviews with DRR practitioners. Data was collected through fieldwork between February and April of 2022, and analyzed using thematic analysis.
The research found that despite an increase in participatory language in Nepal’s policy instruments, practices remain predominantly top-down, with participation often used to legitimize a technocratic agenda. Scientific experts and academics are becoming more influential in the DRR landscape, while the role and efforts of local people in DRR decision-making are still diminished. Participatory spaces are only being used as an instrument to collect ground-level data or communicate risk, and at worst as a tick-box exercise. Public participation in DRR in Nepal faces several barriers, including a lack of clear guidelines and non-binding policy language. Additionally, DRR practitioners on the ground face challenges because of social norms, gendered roles, and elite-dominated structures. Despite recognizing these barriers and the limited impact of participation on decision making, this research observed that DRR practitioners exhibit stagnation or passivity in overcoming them. This stagnation manifests in bureaucratic complacency, where national actors acknowledged the superficial nature of participatory processes on the ground but dismissed the need for change in current practices. Stagnation was also characterized by an external locus of control, where the responsibility for addressing the shortcomings of participation was shifted away from the local actors or national actors, citing reasons for time and funding constraints of project guideline adherence. This stagnation persists by adhering to top-down practices, failing to utilize the opportunities for democratic innovation provided by decentralization.
This research argues that by leveraging participatory approaches, despite the known limited impact on DRR decision making, dominant actors within disaster governance uphold existing hegemonic orders and continue to marginalize communities. The thesis calls for the need to reimagine participatory practices within DRR, ensuring that it is attuned to local context, history, and needs of the vulnerable communities. Finally, the thesis offers reflexive starting points, in the form of identified opportunities, spaces, and guidance, for DRR practitioners
The role of inherited DNA repair deficiencies in cancer susceptibility and evolution
Multiple DNA surveillance and repair mechanisms act on the human genome, maintaining
high replication fidelity and genome stability. Deficiencies in these processes result in an
accumulation of post-zygotic mutations with characteristic signatures. This genomic instability is associated with the heritability of multiple cancer syndromes. I explored the role of inherited DNA repair deficiencies in cancer predisposition, progression and evolution.
Using whole genome sequencing from family trios and a carefully curated variant calling
pipeline, my results support the hypothesis that inherited DNA repair deficiencies impact
germline mutational processes. Offspring from parents with germline DNA repair deficiencies have significantly increased burdens of pre-zygotic de novo mutations (DNMs) with characteristic spectra. However, phenotypic consequences of these DNMs are rare, making them unlikely to cause non-cancer diseases or developmental disorders.
Next, I investigated the recessive inheritance of variants within the base excision repair (BER) genes MUTYH and MBD4, which are associated with colorectal cancer, among other cancer types. The impact of heterozygous variants in BER pathway components is widely debated due to mixed evidence. My analyses utilising germline and somatic data from large publicly available datasets suggest that germline heterozygous variants in MUTYH do not confer significantly increased risk. Heterozygous MBD4 variants are extremely rare but may be linked to cancer susceptibility.
Finally, I identified inherited DNA repair deficiencies in ∼20% of a high grade serous ovarian carcinoma cohort. The mutational profiles of tumours indicate that inherited DNA repair deficiencies are associated with a specific signature and evolutionary trajectory of chromosomal instability. However, there may be alternative routes to chromosomal instability in tumours with proficient DNA repair.
In summary, my work demonstrates how integration of the germline and somatic mutational landscapes increases our understanding of how inherited DNA repair deficiencies impact cancer risk and evolution