62880 research outputs found
Sort by
Modeling bimodal stock price dynamics by a parsimonious diffusion process
No full textWe extend the double-well potential to a three-parameter model in order to capture the momentum and reversal effects in stock price dynamics. The proposed model is characterized by three parameters that control momentum, reversal, and volatility. By varying these parameters, the model can represent two distinct price patterns: (i) a mean-reverting pattern with a unimodal distribution, and (ii) a momentum pattern with a bimodal distribution. We develop an estimation method and establish its asymptotic properties, along with a simulation study to evaluate its finite sample performance. An empirical application using high-frequency data is provided to demonstrate the effectiveness of our proposed model in analyzing price dynamics
Viewing of abstract art follows a gist to survey gaze pattern over time regardless of broad categorical titles
Get PDFArtworks are often shown alongside informative contextual text. This can be as simple as its title and date, or it can be a more descriptive or elaborative explanation of the piece, such as describing its content or explaining the symbolism of the work. Contextual information has been shown to have no impact on early viewing behaviour. A consistent impact on observer eye movement scan paths and fixations is only found in the later periods of looking. One explanation for this is that early eye movement responses to artworks support automatic low-level visual processing that quickly extracts a broad, holistic gist or sense of the works, allowing rapid categorization. The influence of contextual information may only be felt in later periods as it concentrates fixations on descriptive or elaborative elements more quickly and for longer periods. To examine this explanation, we recorded eye movement responses to abstract paintings that were preceded by basic-level categorical labels. In Experiment 1, abstract works were preceded by the labels Landscape, Portrait or Abstract, while in Experiment 2 the labels Action, Still Life or Abstract were given. We found that saccadic eye movements were more common in the first 2 seconds of viewing and were spread over a large portion of the artworks. They became less frequent and were spatially clustered over time. This changing pattern of saccades and their fixation periods was not affected by the contextual information provided by the category labels suggesting a minimal role for top-down control of eye movements when viewers are faced with abstract artworks
Managing concurrent evolution of resistance to fungicides
Get PDFEvolution of resistance to fungicides threatens control of plant pathogens.
Resistance management tactics such as application of fungicides with different
modes of action (MoA) in mixture or alternation can slow selection for resistance,
but it is unclear which strategies work against resistance evolving concurrently to
two or more MoA. In this thesis, mathematical epidemiological models of polycyclic
fungal foliar diseases were used to investigate potential resistance management
tactics.
Use of integrated pest management (IPM) can reduce the fungicide intensity
required for disease control, but resistance management benefits of cultural control
methods are rarely quantified. I developed a model to estimate the resistance
management benefits of a phytosanitary cultural control measure, the ‘soybean-free period’, used in Brazil to delay infection of soybean crops by Phakopsora
pachyrhizi (Asian soybean rust). I considered interactions with use of fungicide
mixtures and varying dose, application rates and timings.
Mixing two MoAs may require splitting the total dose of each MoA across more
applications, increasing exposure time. Using a model of Zymoseptoria tritici
(septoria tritici blotch), I showed that dose splitting of a solo MoA increases
selection, but the effect varies with fungicide properties and the type and
magnitude of resistance. I then compared alternation with ‘splitting and mixing’ as
tactics against concurrent evolution of resistance to two MoA, modelling a sexually
reproducing Z. tritici population. The best strategy varied with fungicide and
resistant strain properties.
Incomplete cross-resistance between active substances with the same MoA could
be utilised for resistance management. I used a novel modelling approach to
investigate the resistance management benefits of within-MoA mixtures with
incomplete cross-resistance. Resistance management benefits were greatest
when the level of cross-resistance between active substances was low or negative;
the rate of selection was also dependent on the variation in the fitness of pathogen
strains against individual mixture components
Toward epistemic justice: using a multimodal Interpretative Phenomenological Analysis methodological approach in research with autistic children
Get PDFIn this paper we critically examine the systemic marginalisation of autistic children’s contributions in research and make the case for how a multimodal application of Interpretative Phenomenological Analysis (IPA) can contribute towards more inclusive and equitable knowledge production. Drawing on an empirical study into the subjective everyday experiences of ten autistic children aged nine to eleven years in mainstream primary schools in England, our research foregrounds the need for methodological innovation to accommodate diverse communicative modalities, particularly among intermittently- and non-speaking participants. By integrating creative adaptations - including photo-elicitation, asynchronous text-based interviewing, and participant-led multimodal engagement – we provide worked examples of how IPA’s flexibility can facilitate more authentic, participant-driven meaning-making processes while maintaining methodological rigour. In doing so, we explore how multimodal IPA can provide a framework for challenging historically dominant neuronormative research practices which can contribute to epistemic injustice. The paper concludes by exploring the broader ethical and practical implications of our study, arguing for the adoption of approaches to research and professional practice that anticipate and accommodate the range of authentic autistic expression in a shift toward greater inclusivity and epistemic equity
Pathogenesis of Noonan syndrome is modulated by NOC2L, a novel interactor of LZTR1 leading to impaired p53 signalling
Get PDFIntroduction Monoallelic dominant-negative LZTR1 gene variants have been implicated as a cause of NS due to hyperactivation of canonical RAS-MAPK signalling. Missense LZTR1 variants have been associated with defective ubiquitination theoretically leading to increased Ras substrate availability and altered p53 signalling. We investigated the role of LZTR1 in this pathway. Methods Single nucleotide substitutions were generated by mutagenesis of an N-terminal MYC tagged-LZTR1-cDNA. WT and variant constructs were expressed in mammalian cells and lysates prepared for phosphoproteomics. Analysis of transcriptomic data was conducted using Ingenuity-Pathway-Analysis. Significant phospho-peptides, protein-protein interactions and pathways of interest were probed using immunoblotting, immunofluorescence, nanoluciferase assays and in silico modelling. Results Two heterozygous LZTR1 variants, affiliated with short stature, were shown in vitro to be thermodynamically stable and associated with elevated pan-Ras levels. Phosphoproteomics revealed upregulation of the histone acetyltransferase inhibitor, NOC2L, in both variants. This finding, consistent upon immunoblotting and immunofluorescence, was associated with impaired p53 acetylation. Major effectors of the DNA damage response (DDR), were preferentially activated in LZTR1 variants. Despite an apparent activation of the DDR and diminished p53 activity, levels of LC3 and phosphorylated-p70 S6 kinase were increased. In silico structure modelling and nanoluciferase assays suggested that LZTR1 interacts with NOC2L, an interaction disrupted in both LZTR1 variants. Conclusion NOC2L and p53 form a complex which dictates p53 activation. We demonstrate a previously unknown interaction between NOC2L and LZTR1 and hypothesise that LZTR1 acts as a binding factor modulating activity of this complex. Since NOC2L negatively regulates p53, its upregulation leads to p53-mediated transcription inhibition. LZTR1 attenuation due to genetic mutations associated with NS, potentiate NOC2L activity leading to reduced apoptosis and a compensatory increase in autophagy
Nutrition and health-promoting characteristics of millets: Evidence from meta-analyses and intervention studies with a focus on diet-responsive diseases in India
No full textMillets have been a traditional staple food in India for some 3000 years although this has declined since the 1960s due to increased replacement by wheat and rice. Millet-based foods are more nutrient dense than refined wheat and rice-based foods in part because they are essentially whole grain. Millets are a more climate-resilient food, which is an increasingly needed characteristic. The prevalence of a range of diet-responsive diseases such as stunting in children and anaemia in children and young women remain very high in India and in many low and middle-income countries. Other conditions such as obesity and related type 2 diabetes are also increasing. Many of the conditions mentioned affect children and young women to a greater degree than men suggesting that children and women of childbearing age should be the primary target of dietary support. Partly because of their high nutrient density compared with refined rice and wheat foods, there is increasing interest in how millet-based foods could help to reduce the prevalence of diet-responsive conditions.
Millets are, however, very variable in their nutritional composition both within and between the different species of millet. Also, there is very little up-to-date information on the bioavailability of key nutrients and how these may be affected by food processing, cooking, etc. The development of a detailed database, at least for India, linking nutritional characteristics and findings from human studies with millet genetic data would seem to be a valuable way forward to capture and understand the factors affecting variability and would also highlight where gaps in knowledge exist. For example, it is notable that despite being the millet species with the highest production in India (62%), pearl millet has not featured very greatly in the studies reviewed in this chapter.
This review chapter has highlighted several recent meta-analyses of prospective studies and related randomised control trials concerning the potential of diets containing millets to reduce the risk of some of the prevalent diet-responsive conditions. There is, for example, some evidence that high iron/biofortified millets can lead to improvements in iron status, which may reduce the risk/ prevalence of iron deficiency anaemia but as mentioned, not all anaemia is simply due to iron deficiency and in this regard, millets cannot enhance the dietary intake of vitamins D and B 12. It is also evident that many of the studies in the meta-analyses are quite old and have used a variety of techniques all reflected in high heterogeneity. Nevertheless, as shown by feeding studies, millets do have promise as part of more complex diets, but more focused and detailed human studies with children and young women are urgently needed in collaboration with the development of millets with enhanced nutritional composition and functionality
Supply management capability, strategic orientation and firm performance
No full textPurpose – This study investigates the performance impact of how supply management capabilities interacts
with firm-level strategic configurations. The research addresses the significant gap in empirical understanding
of whether and how different firm-level strategies moderate the relationship between procurement capabilities
and firm performance.
Design/methodology/approach – Using partial least squares structural equation modelling (SEM),
mediation and moderation effects were tested for the key variables include supply management capability
measured as four routine bundles, strategic orientation using the Miles and Snow typology and two
performance outcomes (operational and financial) on a sample of 518 usable responses from UK-based supply
management professionals.
Findings – The findings reveal that supply management capability positively affects financial performance
but only indirectly through operational performance and only for firms with stable strategic orientations
(prospectors, analyzers or defenders). In contrast, strategically unstable businesses (reactors) lack a
performance impact from supply management capability.
Research limitations/implications – Theoretically, this research advances understanding of the
operational performance value of specific bundles of supply management capabilities by highlighting the
necessity of strategic coherence for capability-driven performance gains.
Practical implications – For practitioners, these findings suggest that managers should prioritize building
supply management capabilities only when their firms have a clear and stable strategy, as such investments
yield no performance benefit in strategically incoherent contexts.
Social implications – The study opens avenues for future research on the dynamics of supply management
during periods of strategic transition and the development of more granular capability measures.
Originality/value – The research addresses the significant gap in empirical understanding of whether and
how different firm-level strategies moderate the relationship between procurement capabilities and firm
performance.
Keywords Strategy, Configuration, Supply management, Capability, Mediation, Moderation
Paper type Research pape
A narrative exploration of leader perceptions and experiences in heritage language schools in the British Isles
No full textHeritage language schools, also referred to as complementary or supplementary schools, offer
cultural and linguistic education outside the mainstream system and play a crucial role in
supporting the UK’s increasingly diverse communities. Despite their contributions, these
schools and their leaders remain underrepresented in educational research and policy
discourse. In an era of globalisation, where multilingualism and intercultural competence are
increasingly valued, national strategies for English as an Additional Language (EAL)
provision remain limited, reflecting broader patterns of linguistic and cultural
marginalisation.
This study presents a narrative inquiry into leadership within heritage language schools in the
British Isles, addressing a significant gap in the literature. Drawing on semi-structured
narrative interviews with twelve school leaders (seven Chinese, three Greek, one Italian, and
one Czech), the research explores how perceptions, personal values and lived experiences
shape professional identities and leadership practices.
The study investigates three central research questions:
1. How do twelve heritage leaders perceive their values and professional identities, and
how have these shaped their leadership practice?
2. How do they perceive their school’s context and culture, and how has this influenced
their leadership practice?
3. What are each leader's perceptions and experiences of leadership learning, and what
are their developmental needs?
To enrich the qualitative data, participants completed the Schwartz Portrait Values
Questionnaire (PVQ), offering deeper insight into their motivational value systems. The
integration of the PVQ results with narrative data revealed how leaders’ values and school
contexts inform their leadership approaches.
Findings indicate that heritage school leaders navigate complex challenges through
collaborative and community-oriented practices. Key developmental needs and implications
include access to continuing professional development (CPD), clearer guidance on
educational policy, financial and legal frameworks, human resource management, and
strategies for community engagement. The study highlights the value of culturally responsive
communities of practice (COPs) and regular forums to foster mentoring and collaboration
between heritage and mainstream education sectors. This research contributes to a deeper
understanding of leadership in heritage language schools and the importance of supporting
these vital educational spaces