21684 research outputs found
Sort by
Investigating trait-based capture vulnerability and the potential for selection in the Amazonian ornamental fishing industry
Full text linkThe harvest of animals from the wild is a pervasive selective force, especially in fisheries, where harvesting often targets individuals with specific traits. Early research on trait-based selection was particularly focussed on traits related to age and size at maturation, but there has been a more recent shift toward understanding how traits beyond growth, such as behavioural and physiological traits, may also be targets of selection. Indeed, there is now emerging evidence from commercial and recreational fisheries that individuals with physiological traits related to metabolism and swimming performance are more likely to be captured, as are fish with behavioural traits related to exploration, risk-taking, and group cohesion. However, the direction of selection has been found to be largely dependent on the type of gear used, with more active gears such as trawls targeting traits relating to swimming capacity, and more passive gears such as traps targeting traits related to increased risk-taking and exploratory behaviour. Many of the traits under selection are also influenced by environmental factors such as temperature and oxygen availability, but how environmental factors modulate capture vulnerability is currently not well understood. Another important gap in fisheries selection literature is that some fishery sectors have been completely overlooked including smaller-scale artisanal fisheries such as the ornamental trade, a global industry with important repercussions for sustainability, biodiversity, and the livelihoods of local communities.
In this thesis, for the first time, I aimed to uncover if there was a potential for trait-based selection in the ornamental fishing industry, specifically in the Amazon, which is home to a large proportion of wild-caught ornamental species. Using a combination of lab-based studies and field observations, I investigated capture vulnerability and compared phenotypes of key ornamental species caught using different gears. I also examined the impact of environmental factors on behavioural and physiological traits to determine if the environment can modulate relationships between individual phenotype and capture vulnerability.
Chapter 1 introduced the main research themes and highlighted the key knowledge gaps that were addressed in this thesis. In chapter 2, I used a scaled-down fisheries simulation that has been used in previous studies focussed on commercial and recreational fisheries. Unlike previous studies, which have used surrogate species, I used an actual target species of the trade, the cardinal tetra (Paracheirodon axelrodi), which is a highly popular ornamental species. I repeatedly caught individuals to determine their vulnerability to capture and tested whether vulnerability to capture can be predicted by phenotype. I revealed that capture vulnerability is predicted by a suite of traits, namely size, swimming endurance, exploration, and risk-taking.
In chapter 3, I caught wild populations of cardinal tetra using active (net) and passive (trap) gear types and examined differences in behavioural and physiological traits in the lab. I used a range of assays including constant acceleration tests, maze tests, open field, and novel object tests. Trap-caught fish were larger and had a lower swimming performance compared to net-caught fish. In contrast, net-caught fish were more cohesive and active, but specific results varied across assays. Social and environmental factors also influenced findings, with differences in risk-taking revealed between individuals and groups and even small variations in ambient temperature during trials significantly influencing behaviour.
In chapter 4, I used a completely field-based approach to investigate the ornamental capture process in-situ. Using underwater recording of traps in the Amazon, I observed behaviours for two species, the spotted tetra (Copella nattereri) and Hemigrammus Spp., including pre-capture behaviours such as passes and inspections, which have not been observed in the majority of fisheries selection studies. The observations revealed that the majority of fish that inspected traps did not enter them, and while the likelihood of capture was similar for both species, once a given trap had caught one species, it would not catch the other. There were also differences between species in the frequency and timing of behaviours, such as passes and inspections. There was also a relationship between environmental factors and behaviours, but these differed between species, highlighting the importance of integrating multiple species in studies.
In chapter 5, I captured spotted tetra using active (net) and passive (trap) gears and examined behavioural traits of groups using open field and novel object tests after a short acclimation time. I also investigated the impact of an acute temperature increase on behavioural traits. I found that trap-caught fish were more exploratory and showed greater group cohesion, while net-caught fish were more active. Interestingly, there was limited evidence that exposure to an elevated temperature influenced any behavioural traits apart from cohesion. However, group identity accounted for a large amount of behavioural variation, as individual responses were masked at the group level, highlighting an important dynamic to consider when interpreting the potential for selection.
Finally, in chapter 6, I summarised the key findings and overarching themes of my thesis. I discussed the potential for selection in the ornamental fishing industry and highlighted how my findings contribute to the existing body of literature. I then provided an overview of the challenges and limitations of my thesis and provided some future directions for the field.
Taken together, my thesis provides an important foundation towards understanding the potential for selection in ornamental fisheries. Using lab simulations and field observations across different environmental contexts, this thesis shows that capture is not random, but trait based. This thesis also highlights the potential for gear-based selectivity in the ornamental fishing trade, which can have important repercussions for biodiversity and conservation. This thesis also raises questions about how selection operates in different environmental conditions or how group dynamics can mask individual responses. In summary, this thesis contributes a novel perspective on fisheries-induced selection by focusing on a previously overlooked system and broadens our understanding of how artisanal fisheries can shape wild populations
What we talk about when we talk about smells: a corpus study of the language of olfaction
Full text linkOne of the fundamental uses of language is that it allows us to communicate the things we perceive with our senses. While most of the senses have dedicated vocabulary which speakers can draw on to describe their experiences—visual colour terms, taste terms like sour, words to do with hearing like loud or texture like rough—the sense of smell is less lexically well served, in English at least.
In light of this paucity of dedicated vocabulary, this thesis seeks to find which words and linguistic strategies English speakers use when they wish to put complex olfactory experiences into words. It accomplishes this through the investigation of a purpose-built corpus of fragrance reviews taken from the perfume community website Fragrantica. It first establishes the key semantic domains of the corpus, before providing a corpus-driven analysis of the language of olfaction around each of these key domains. This analysis begins with those domains most semantically distant from the sense of smell (like Time), then moves towards the senses in semantic space with an analysis of words to do with the linked domains of Food and Plants, before offering an analysis of directly sensory words themselves. Finally, it deals with more complex olfactive descriptions which use aspects of character and setting to communicate olfactory information.
Through investigating the semantics of olfactive language in this corpus-driven way, this thesis presents three main conclusions. First, it argues that when source-based descriptors are employed in olfactory description, non-olfactory components of those descriptors also play a role in generating olfactive meaning. Second, that a primary strategy for communicating olfactive meaning is through connotation and association rather than direct sensory description. And third, that when words from non-olfactory sensory domains are used to communicate olfactive meaning, this cross-modal use does not represent a metaphoric transfer of meaning, but rather indicates that the semantic domains of the senses are so closely and densely linked that they can be considered a contiguous domain of perception
Post-processing in perovskite solar cells: challenging your assumptions
Full text linkExploiting the vast source of energy provided by the sun is one of the most promising pathways towards reducing fossil fuel use and shifting to renewable energy sources. The development of novel solar cells is thus of high importance to maximise the benefits this approach can provide. In the field of cutting-edge photovoltaic technologies, perovskites have emerged as one of the best-performing candidates for the solar cells of the future. Much of the research into perovskites is now focused on tackling some of the issues they face limiting their potential for industry-level adoption. The implementation of a related class of materials, know as Layered Perovskites (LPKs) is an increasingly popular approach to achieve the requirements of longevity and high efficiencies.
Here, the unique combination of properties provided by the alternating organic and perovskite sheets results in a highly-tunable hybrid material that is stable and well-suited to improving performance across a range of perovskite solar cell compositions. Whilst the implementation of LPKs is a well-established avenue of research, questions still remain about some of their fundamental properties.
The work presented in this thesis seeks to challenge some of the assumptions that are universally applied to LPKs as a whole. The interplay between the organic components and the perovskite backbone is found to be highly complex, and it is difficult to draw clear relations between the chemistry of the A’ cation, the material structure, and its optoelectronic properties. Many of the highly desirable properties such as improved stability are not strictly applicable to the extremely thin layers that are most widely utilised within solar cells, which readily degrade in ambient conditions. Indeed, the solar cell fabrication process can disrupt the LPK or even remove it entirely, highlighting that great care must be taken when exploring the mechanism behind their benefits to performance and stability
The shaping of conforming dispositions of educationally and socially disadvantaged higher secondary school students in rural Uttar Pradesh, India: a case study
Full text linkThis research investigates the role of school practices in reinforcing and informing the conforming disposition of higher secondary school students in India. The study contributes to developing an understanding of the mechanisms by which conformity is incorporated within individuals and how caste is perpetuated through schooling. The project employs Bourdieu’s concepts of habitus (its constituent dispositions) and practice to explain the school's role in perpetuating inequalities.
The study is a case study of a low-fee private school situated in a rural area of Uttar Pradesh, a northern state in India, which is educationally, socially, and economically disadvantaged. The Biographical Narrative Interview Method (BNIM) is employed to gather the data. I conducted in-depth interviews with 12 students across three rounds, all from socially and educationally disadvantaged backgrounds, also known as Other Backward Classes (OBCs). Data were thematically analysed to reveal the school's dominant practices and identify the dispositions expressed through repetition.
The study's findings indicate that school’s unofficial pedagogic practices of authority, obedience, and hierarchy shape students' dispositions. I captured two aspects of students’ dispositions from the data: cognitive and affective. Conforming dispositions represent the cognitive dimension of dispositions, characterised by cognitive patterns of non-questioning and reduced agency of individuals. At the same time, affective dispositions represent embodied emotions of respect, fear and honour. These dispositions possess the potential to provide unthought guidance to the generation of caste-based practices of untouchability and endogamy through which caste inequality is reproduced.
Literature shows that schools enforce obedience and cultural morality characterised by hierarchy. This research presents the next level of analysis of such school practices, demonstrating that the everyday life of school embodies conformity as dispositions, with the potential to reproduce prevailing social relations and undemocratic virtues. Moreover, the significance of the research lies in demonstrating that informal school practices, such as authority, obedience, and hierarchy, should be taken seriously alongside official pedagogic practices, while discussing the role of the school in social reproduction/transformations
Elucidating the role of CD180 as a novel marker of chemotherapy resistance in paediatric KMT2A-rearranged acute myeloid leukaemia
No full textAbstract not currently available
An investigation of systemic inflammation and clinical outcomes in patients with common solid tumours
Full text linkSystemic inflammation is increasingly recognised as a key determinant of clinical outcomes in patients with solid tumours, influencing tumour progression, treatment response, and survival. This thesis evaluated the prevalence, prognostic value, and clinical utility of systemic inflammation–based markers and scores across common cancers, including non-small cell lung cancer (NSCLC), oesophagogastric (OGC), and colorectal cancer (CRC). A series of retrospective cohort studies and a systematic review/meta-analysis were conducted to assess markers, including the neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), C-reactive protein/albumin ratio (CAR), and the modified Glasgow Prognostic Score (mGPS).
The findings demonstrate that systemic inflammation is common across these cancers but varies in magnitude by tumour type, stage, and host fitness, with advanced NSCLC showing the highest inflammatory response. CRP-based scores (CAR, mGPS) consistently provided more substantial prognostic value than ratios derived from differential white cell counts, par-ticularly in operable OG and CRC, where baseline inflammation was lower. In NSCLC, sys-temic inflammation was associated with nutritional decline, survival after immunotherapy, and prognosis independent of conventional clinicopathological factors. The meta-analysis further confirmed the predictive utility of inflammatory biomarkers in NSCLC patients re-ceiving immunotherapy.
Overall, this thesis highlights systemic inflammation as a clinically relevant prognostic factor across multiple solid tumours, with CRP-based measures emerging as the most sensitive and reliable indicators. These findings support the routine use of CRP in prognostication and pa-tient stratification and suggest its potential role as both an inclusion criterion and an outcome measure in future interventional studies of anti-inflammatory therapies in cancer
Exploring the relationship between suicide-related stigma and suicide risk
Full text linkBackground: Suicide is a major public health concern with around 727,000 people dying by suicide globally each year. Research in the field of suicide aims to understand the risk factors associated with suicide and how best to prevent suicide. However, despite growing research in the area, suicide-related stigma remains under researched as a potential risk factor for suicide. Although there has been an increase in research and a growth in the conversations around suicide, it is still seen as taboo within society and remains illegal in some countries. Progress has been made to better understand suicide, with theories investigating biological, psychological and sociological factors associated with suicide risk. Recent reviews also highlight that suicide-related stigma is associated with several negative outcomes for those bereaved by suicide. Therefore, it is important for further research to understand whether similar outcomes exist among those who have attempted or thought about suicide. It is also important to understand how suicide-related stigma differs across demographic characteristics and how best to mitigate this stigma. Therefore, this thesis aims firstly to examine group differences in suicide-related stigma and experiences, and secondly to understand its impact on those with lived experience.
Methods: This PhD thesis comprises five research chapters. It begins with a scoping review which aimed to understand the associations between suicide-related stigma and help-seeking, grief, mental health and suicide risk (n = 100 studies). Chapters 3 and 4 present the findings from a quantitative study. Chapter 3 investigated associations between suicide-related stigma, help-seeking, mental health and suicide risk, and whether stigma levels differed by age, gender, education and suicidal history. Chapter 4 examined mechanisms behind stigma within the Integrated Motivational-Volitional (IMV) Model using mediation analyses. Chapters 5 and 6 relate to qualitative interviews (n = 30) which were conducted as part of this thesis. Chapter 5 used the Framework analysis method to understand whether the experiences of those who had attempted suicide differed from those who had thought about suicide with regards to suicide-related stigma. Finally, Chapter 6 aimed to provide recommendations for the reduction of suicide-related stigma based upon suggestions of those with lived experiences using Reflexive Thematic Analysis.
Results: The scoping review (Chapter 2) highlighted the negative effects of suicide-related stigma, such as a higher risk of suicidality, poor mental health, lowered help-seeking intentions/behaviours and grief-related difficulties among those bereaved by suicide. Suicide-related stigma was found to be related to feelings of isolation, shame and secrecy. A small number of studies discussed the protective nature of suicide-related stigma in that it can encourage help-seeking. The scoping review allowed for the development of a novel model of suicide-related stigma which displays the directionality of these associations. In the first quantitative study (Chapter 3, n = 470 participants), males were found to stigmatise those who die by suicide more than females. The analyses in Chapter 3 also found that individuals with a history of suicide (thoughts or attempts) held fewer stigmatising attitudes towards those who die by suicide but more stigmatising attitudes towards those bereaved by suicide and suicide attempts compared to those without a suicidal history. Chapter 3 found significant associations between suicide-related stigma and higher levels of depression, anxiety and suicidal ideation as well as lower help-seeking intentions. In Chapter 4 (additional analyses from the survey reported in Chapter 3), serial mediation analyses revealed that defeat and entrapment fully mediated the relationship between the glorification of suicide, suicide-related stigma measures and suicidal ideation. Chapter 5 explores the findings from the qualitative study. A key finding was that those with a history of suicide attempts had similar experiences regarding suicide-related stigma to those with a history of suicidal thoughts. Five themes were developed from the interviews: 1) “suicide is stigmatised;” 2) “it’s like the elephant in the room, nobody wants to talk about it;” 3) “I was so ashamed;” 4) “I think generally people think suicide is selfish, cowardly, inexplicable, mad;” and 5) “So I guess it’s about being taken seriously and being believed almost.”. These themes captured the silence and secrecy around suicide, the negative labels attached to those who experience suicidality and the shame associated with these experiences as well as the experience of their reasons for their suicidality being questioned. Finally, Chapter 6 (further analyses from the interviews described in Chapter 5) explored the consequences of suicide-related stigma and yielded suggestions from those with lived experience regarding how to reduce the stigma related to suicide. These analyses identified three themes related to the impact of suicide-related stigma: negative consequences, positive and supportive reactions, and no impact. Most of the participants described the negative consequences of suicide-related stigma such as lowered help-seeking and poor mental health outcomes. Regarding how suicide-related stigma could be reduced, two themes emerged from the transcripts: education and open conversations. Most of the participants described the importance of education in schools and workplaces to mitigate suicide-related stigma as well as the importance of having open and non-judgmental conversations around suicide.
Conclusion: To my knowledge this thesis includes the first literature review of its kind, a scoping review investigating the associations between suicide-related stigma and help-seeking, mental health, grief, and suicide risk among different groups of individuals. This review led to the development of a model explaining the directionality of the associations between suicide-related stigma and the outcomes explored within the review. The quantitative and qualitative studies provided novel findings, such as defeat and entrapment mediating the stigma–ideation relationship and lived-experience accounts of the impacts of suicide-related stigma and potential interventions to reduce stigma. The findings reveal possible groups for intervention, such as men (Chapter 3) while also highlighting the similarities in the way those affected by suicide experience stigma. The evidence presented in this thesis has important implications for policy and clinical practice
Towards a better understanding of confidence: evaluation and advancement of confidence models
No full textAbstract not currently available
Macrovascular aspects of hypertension mediated organ damage
No full textAbstract not currently available
S-palmitoylation and regulation of the cardiac transient outward current
No full textAbstract not currently available
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇