69238 research outputs found
Sort by
Structural Phylogenetic Analysis of Bacterial Flagellum Rotor Protein FliG and its Non-flagellar Homology, the Magnesium Transporter MgtE
No full textThe bacterial flagellum is a complex nanomachine where dozens of different proteins cooperate to produce rotary motion powered by ion flow. Many flagellar proteins have homologs in non-flagellar systems, suggesting that this adaptation originated by coopting proteins initially serving simpler functions. One example of a flagellar/non-flagellar homolog pair is FliG (flagellar rotor protein) and MgtE (Mg²⁺ transporter). Despite their distinct function, FliG and MgtE share structural homology in ARM-repeat domains despite low sequence identity ("twilight zone"). Phylogenetic analyses that include structural data in the form of Foldseek’s “3Di” (three-dimensional) characters derived from AlphaFold2 structural predictions indicate that both form distinct, well-supported monophyletic clades. Structural superposition reveals conserved ARM-fold geometry (RMSD ≤2.67 Å). Phylogenetic analysis focused on ARM-repeat domains demonstrates clear separation among FliG’s three domains (FliG-N, FliG-M, FliG-C) and MgtE, each forming strongly supported, distinct clades. Comparative structure-based phylogenetic analyses revealed internal homology among the FliG N, M, and C domains, consistent with a model in which the tripartite organization of FliG arose through serial duplication (triplication) of an ancestral ARM-repeat unit. While these findings support a plausible structural model for FliG evolution, the directionality and timing of such duplication remain unresolved
CR-Dynamical Systems
No full textWe study transitive points, transitivity, mixing, and the shadowing property in CR-dynamical
systems, that is, compact Hausdorff spaces paired with a closed relation (CR). In Chapter 1, we
provide an introduction to CR-dynamical systems, and basic definitions used throughout this
thesis. CR-dynamical systems generalise topological dynamical systems, allowing for points to
have multiple, or even no trajectories. To account for multiple trajectories, the aforementioned
dynamical properties split into multiple types. Three types of transitive points have been introduced
for CR-dynamical systems. We introduce a new fourth type in Chapter 3. In Chapter 2,
we develop a new tool called transitivity trees, which we use in Chapter 3 to determine the
relationship between the four different types of transitive points. We introduce a new second
type of transitivity and mixing in Chapter 4 for CR-dynamical systems. Finally, in Chapter 5,
we introduce four different types of shadowing properties to CR-dynamical systems, extending
previous work on shadowing in set-valued dynamical systems
Student strategies for surviving social work education in Aotearoa New Zealand
No full textINTRODUCTION: There is a growing literature reporting on the stressors facing social work students as they move through their social work education. This article reports on part of a study of student hardship that asked Aotearoa New Zealand social work students about the strategies that they utilised to maintain their wellbeing, and to offer their advice to future students.
METHOD: A mixed methods study incorporating a survey (N = 353) and 31 semi-structured interviews was conducted in Aotearoa New Zealand in 2019. Participants in the study were then current students or new graduates in their first two years of practice at the time the research was conducted.
FINDINGS: Student participants reported various strategies used to support their progress through their social work study. The survey results indicated a strong reliance on relational supports with peers, family/whānau and friends. Qualitative themes were developed, including: individual, relational, institutional, cultural and societal supports reported by the students. Participant advice to future students added an intrapersonal attribute of self-knowledge.
CONCLUSIONS: While it is important to learn from the students about the strategies and supports that were useful in sustaining them and enhancing their resilience, the importance of considering structural challenges and the need to resist neoliberal policies and conditions are also critical
A virulent soil pathogen alters temperate rain forest understorey sapling population dynamics and successional trajectories
No full textAims: Understanding the impacts of forest tree pathogens on understorey sapling populations is critical for understanding their population-level effects and the likely successional trajectories of infected communities. We assessed the impacts of Phytophthora agathidicida, a soil-borne pathogen, on the sapling population dynamics of the disease-susceptible, locally dominant canopy tree, the conifer kauri (Agathis australis, Araucariaceae). We also examined the indirect effects of P. agathidicida on likely resistant allospecifics that span a range of shade-tolerances as saplings, to predict future successional trajectories.
Location: Waitākere Ranges, west of Auckland, Aotearoa-New Zealand.
Methods: We analysed data from four kauri-dominated permanent plots in Aotearoa-New Zealand warm temperate rain forests. Two plots were early-successional and two were late-successional, one in each pair had overstorey kauri showing intense visual
P. agathidicida symptoms, and the other overstorey kauri showing few symptoms. We examined the association between kauri trees and saplings using point pattern analysis and the relationship between the level of crowding around saplings and their
growth and survival rates. We compared the growth and survival rates of kauri and allospecifics, categorised by shade tolerance, among the plots.
Results: Kauri forms sapling banks under conspecific trees that were less dense in late-successional forests and in those where the overstorey kauri showed symptoms of P. agathidicida infection. Despite having lower densities, kauri sapling growth rates
were higher in symptomatic plots. The growth rates of light-demanding allospecifics were also higher in these plots, with minor differences in mortality and growth rates for more shade-tolerant allospecifics. P. agathidicida may promote sapling growth and
survival of kauri and some allospecifics in infected plots.
Conclusions: Sapling vital rates and population sizes differed between asymptomatic and symptomatic plots, particularly in early-successional settings, where P. agathidicida may reset succession in early-successional communities back to those dominated by species that first colonised after disturbance
Mapping the Sheep Cochlear Arterial System in 3D: Qualitative and Quantitative Analyses
No full textHearing loss is a global health problem affecting ~1.5 billion people worldwide. The pathophysiology of sensorineural hearing loss (SNHL) is not fully understood, but vascular dysfunction is implicated in some SNHL aetiologies. Characterising cochlear vascular anatomy is crucial to understanding the repercussions of altered cochlear blood flow on cochlea physiology and its role in SNHL. Whilst cochlear vascular anatomy is well characterised in small animals, the connectivity between blood vessels remain unclear. Furthermore, cochlear vasculature is poorly characterised in large animals, which are more similar in size to human cochlea and thus are more suitable as a translational model. Our lab used sheep as a large animal model and obtained 3D data of cochlear vascular anatomy using microcomputed tomography (microCT). This study aims to establish a protocol to analyse contrast-enhanced microCT datasets of sheep cochlea and qualitatively and quantitatively characterise sheep cochlear vasculature in 3D.
First, a protocol to optimise the provided sheep cochlea microCT datasets was developed. In this optimisation process, the sheep microCT datasets were reduced in size, binarised to separate the cochlear vasculature and bony labyrinth information, then processed to obtain clean segmentations of the cochlear arterial system and bony labyrinth. 3D data analysis, showed that the sheep cochlear arterial system formed a tree-like architecture, where many branches radiated from the main blood vessel in the centre. The spiral modiolar artery (SMA) was the main artery that supplied the sheep cochlea. The SMA spiralled up the modiolus and became more convoluted as it travelled apically. The average length of SMA in sheep cochlea was 7.429mm. Three levels of highly convoluted radiating arterioles (RA) branched off from the SMA – Primary, Secondary and Tertiary RA - which collectively were termed the ‘SMA branching system’. The architecture of the cochlear arterial system was more complicated in the first turn than the second turn due to an increased number of ramifications. Overall, the sheep cochlear arterial system closely resembles other mammals, including humans. The similarity between sheep and human cochlea size and vascular anatomy substantiates the use of sheep as a translational model to investigate SNHL pathophysiology and novel therapies
Entity/Relationship Graphs: Principled Design, Modeling, and Data Integrity Management of Graph Databases
No full textChen's Entity/Relationship (E/R) framework is a lingua franca for well-designed databases. We define E/R graphs as property graphs that are instances of E/R diagrams. As the latter are a subclass of PG-Schema, E/R modeling constitutes a methodology for designing graph databases that guarantee data integrity, the absence of data redundancy and update anomalies. In addition, E/R graphs provide the first graph semantics for E/R diagrams. Further to the unification of conceptual and graph data modeling, referential integrity for E/R graphs can be managed by directed edges, called E/R links, between nodes. As a consequence, redundancy and sources of potential inconsistency can be eliminated, minimizing update maintenance. This is achieved by E/R keys that use properties and E/R links to enforce entity integrity, in contrast to property keys that rely exclusively on properties to enforce entity integrity. We use the TPC-H benchmark as running example and for extensive experiments that quantify the effort for i) managing entity integrity using property keys or E/R keys, ii) managing referential integrity using property redundancy or E/R links, iii) query evaluation. In summary, E/R diagrams form a principled core of PG-Schema for well-designed property graphs, while E/R keys constitute an efficient core of PG-Key for data integrity management
Sustainable Symptoms: Olympism, Air Transportation, and Fetishistic Disavowal
No full textOlympic discourse presents a story of a global movement that places “sport at the
service of the harmonious development of humankind” (IOC, 2023a). Conversely,
the instantiation of this mythology in the Olympic Games is riven with the contradictions of contemporary capitalism, from the displacement of residents to the exploitation of workers and the transfer of private risk to public host cities. One issue
has become especially evident: the substantial environmental impact of the Games.
In this theoretical intervention, I explore the Olympic Movement’s response to
this impact and the climate crisis through an analysis of its environmental discourse.
Using the post-Lacanian concept of ideological fantasy, I argue that Olympic environmental discourse mobilizes its humanist mythology to construct an imagined sustainable future in which “climate positivity” is achievable through local changes that do
not disrupt the commercial structure of the event. Conversely, I suggest that air
transportation emissions—the largest source of emissions but barely present in
Olympic sustainability strategies—are symptomatic of the structural unsustainability
of the Olympic Movement. In order to make the absent presence of this symptom
more palatable, I contend that a process of fetishistic disavowal occurs in which spectator travel is dismissed as “unavoidable.
生成式人工智能反馈对大学生英文作文质量的增值效益研究 = Exploring the value-added benefits of GAI feedback on English writing quality among Chinese university students
No full text近年来，生成式人工智能 （generative artificial intelligence，简称 GAI） 在外语教育领域得到了广泛应用。其中，在外语写作教学方面，GAI 可针对学生写作表现提供即时反馈，从而得到教师的认可。本研究聚焦中国大学英语课堂写作教学，采用教学实验，探究 GAI 反馈在教师反馈基础上对学生英文作文质量的提升有何增值效益。基于两个大学英语平行班 87 名非英语专业大学生的四次作文反馈前后的写作表现，研究发现：（1） 教师+GAI 反馈和教师反馈均能有效提升大学生英文写作质量；（2） 随着反馈次数的不断积累，GAI 反馈对写作质量的增值效益会凸显。本研究的结果对 GAI 反馈在外语写作教学中的应用具有一定的启示意义。
Generative artificial intelligence (GAI) has been widely applied in foreign language education in recent years. Given its capability to provide immediate feedback on students' writing performance, GAI has gained great popularity among foreign language writing teachers. This study employed a classroom-based experimental design to examine the value-added benefits of GAI feedback, when used alongside traditional teacher feedback, in enhancing Chinese university students' English writing quality. Data analysis was conducted on the pre- and post-feedback writing performance across four essay tasks collected from 87 non-English major university students from two parallel classes. Results showed that: (1) both teacher+GAI feedback and teacher feedback effectively enhanced students' English writing quality; (2) the value-added benefits of GAI feedback on writing quality became more pronounced with accumulated feedback iterations. These findings have practical implications for the integration of GAI feedback into foreign language writing pedagogy
The public health response to COVID-19 in the Auckland region and Te Tiriti o Waitangi
No full textBackground: The COVID-19 pandemic was an unprecedented event, forcing health systems across the world to rapidly respond to the evolving risk of widespread illness and death. In Aotearoa, New Zealand, Maori have experienced long-standing and significant health inequities compared to non-Maori, and COVID-19 was predicted to disproportionately affect Maori whanau and communities, particularly in Auckland, which bore the brunt of COVID-19 in the first two years of the pandemic.
Aotearoa, New Zealand is founded on Te Tiriti o Waitangi, the agreement between Maori and the British Crown. The Waitangi Tribunal has concluded that the extent to which the Government has honoured Te Tiriti o Waitangi has been insufficient, although the requirement to align with Te Tiriti is acknowledged by the health system. This research sought to understand whether the public health response to COVID-19 in Auckland aligned with Te Tiriti o Waitangi, particularly the principles of Tino Rangatiratanga and Options. The research specifically focused on the Delta outbreak and early phases of the Omicron outbreak in late 2021 and early 2022.
Methods: Qualitative research methods, informed by Kaupapa Maori theory and research methodology, were used to explore the alignment of the public health response with Te Tiriti o Waitangi. Six semi-structured interviews were undertaken with key health leaders involved in the Maori COVID-19 response to understand their perspectives and experiences, which were then analysed via thematic analysis.
Results: The findings of this research reaffirmed the complex and dynamic Te Tiriti o Waitangi relationship between Maori and the Crown. Three main themes were identified: (1) Maori acted sovereign during the response, (2) the system attempted to
maintain the status quo, and (3) there was a struggle of 'give and take' relationships between Maori and the Crown. Each theme had several sub-themes.
Conclusion: This research suggests that, although there were examples of Maori-led innovations and models as part of the
COVID-19 response, overall the Auckland region response failed to align with Te Tiriti o Waitangi. The Crown must implement transformative structural and behavioural changes to design and deliver health services that align with Te Tiriti o Waitangi for any future pandemics
Co-researching Environments: A Practice Research Partnership Exploring Strategies to Address Food Insecurity
No full textA co-researching environment describes the conditions that enable equitable partnership: who is involved, how power is shared, how knowledge is generated, and how outputs are embedded into wider systems. Using a practice research partnership on food insecurity in Aotearoa New Zealand as an illustrative case, this article shows how “co-researching environments” can guide the conduct and outputs of collaborative research. Data were collected through six virtual workshops and reflective dialogues with 25 practice partners and analyzed using hybrid thematic analysis, informed by a Practice Ecosystems Framework. Analysis highlighted four adaptive processes (co-creating, co-learning, co-producing, and co-shaping) through which collaboration was enacted, and three community-led strategies (negotiating, embedding, innovating) to address food insecurity. While strategies addressing food insecurity are context-specific, it requires a collective approach. “Co-researching environments” outline conditions to respond to increasing calls for collaborative knowledge generation that aligns research and service development