110830 research outputs found
Sort by
Bayesian modelling and computation utilising directed cycles in multiple network data
Get PDFModelling multiple network data is crucial for addressing a wide range of applied research questions. However, there are many challenges, both theoretical and computational, to address. Network cycles are often of particular interest in many applications; for example in ecology a largely unexplored area has been how to incorporate network cycles within the inferential framework in an explicit way. The recently developed Spherical Network Family of models (SNF) offers a flexible formulation for modelling multiple network data that permits any type of metric. This has opened up the possibility to formulate network models that focus on network properties hitherto not possible or practical to consider. In this article we propose a novel network distance metric that measures similarities between networks with respect to their cycles, and incorporates this within the SNF model to allow inferences that explicitly capture information on cycles. These network motifs are of particular interest in ecological studies aimed at understanding competitive and hierarchical interactions. We further propose a novel computational framework to allow posterior inferences from the intractable SNF model for moderate-sized networks. Lastly, we apply the resulting methodology to a set of ecological network data studying aggressive interactions between species of fish. We show our model is able to make cogent inferences concerning the cycle behaviour amongst the species, and beyond those possible from a model that does not consider this network motif
Perceived fairness of conservation decision-making more strongly influenced by absence than presence of procedural equity criteria
Get PDFPeople’s perceptions about how fair conservation decision-making is can play a critical role in whether they support and comply with conservation efforts. Termed procedural equity, fair decision-making is emphasized in policy and practice due to its ethical and instrumental importance. However, limited understanding of what contributes to perceptions of fair decision-making may hamper efforts to foster procedural equity. We analyze quantitative survey data to examine how six criteria of procedural equity (accountability, correctability, voice, decision control, transparency, and trust) are related to perceptions of fairness in decision-making for 1799 residents of Australia’s Great Barrier Reef Marine Park. We find that: 1) five out of six procedural equity criteria are related to perceived fairness of decision-making; and 2) the absence of procedural equity criteria has a generally stronger relationship to perceived (un)fairness in decision-making than the presence of procedural equity criteria. Rather than making assumptions about what constitutes fairness, we empirically demonstrate the relative importance of each criterion in promoting perceptions of fairness in conservation decision-making. Comparing the uneven relationship between absent and present criteria to perceived decision-making fairness highlights the strong negative impacts that ignoring procedural equity concerns can have for conservation projects
A comparison of schizophrenia-risk GRIN2A gene variants Q655* and R695Q on brain and monoaminergic and GABAergic neurotransmitter system function
No full textDysfunctional neurotransmitter systems contribute to the pathophysiology of schizophrenia. Mutations in the GRIN2A gene, which encodes the GluN2A subunit of the N methyl-D-aspartate receptor (NMDAR), have been suggested to contribute towards aberrant NMDAR functioning and are associated with an increased risk of schizophrenia. In this study, I investigated the effect of ultra-rare variants in GRIN2A associated with schizophrenia, including the protein truncating Grin2a.Q655* (Grin2a.QX) and missense mutation Grin2a.R695Q (Grin2a.RQ), on brain and neurotransmitter system function. I used 14C-2-deoxyglucose (14C-2DG) functional brain imaging to investigate cerebral metabolism in schizophrenia-related brain regions in Grin2a.QX mutants, under baseline conditions and after challenge with the monoamine neurotransmitter releasing drug d-amphetamine. Quantitative PCR (qPCR) was used to examine mRNA expression levels of genes involved in monoaminergic and GABAergic neurotransmitter systems, and Western blotting used to evaluate protein expression of important receptors implicated in schizophrenia pathophysiology. Gene expression markers of neurogenesis in the hippocampal dentate gyrus (DG) were also characterized. The Grin2a.QX mutation induced hypermetabolism in the DG, but did not alter metabolism in any other brain region characterized, including in subregions of the prefrontal cortex (PFC) and basal ganglia. In the PFC, markers for Sst expressing GABAergic cells were altered in Grin2a.QX mice, but GABAergic cells remained unaltered in the hippocampus. In addition, markers for early radial glial cells (RGL) involved in DG neurogenesis, Zic5 and Glis3, were upregulated, but markers of later stages of DG neuronal maturation were unaltered, in hippocampal samples from Grin2a.QX mice. Interestingly, the metabolic response to d-amphetamine was unaltered in Grin2a.QX mutant mice, suggesting that monoaminergic system function was not grossly altered in these animals. In addition, monoaminergic transporters and receptors involved in the d-amphetamine response were largely found to be unaltered at the mRNA (Htr2a, Vmat2) and protein level (D2R, 5-HT2AR), further suggesting Grin2a.QX mutation has a limited impact on monoaminergic system function. In contrast to Grin2a.QX mutants, the Grin2a.RQ mutants displayed more widely altered GABAergic (Lamp5 and Vip) and serotonergic (Htr2a) gene expression in the PFC, with limited effects seen in the hippocampus. This aligns with previous work showing that the Grin2a.RQ mutation impacted cerebral metabolism in the PFC but not the hippocampus. Overall, this study found that the two Grin2a variants associated with schizophrenia have differential impacts on brain and neurotransmitter system function, despite the mutations being in the same gene. The Grin2a.QX mutation primarily affected the hippocampus, specifically the DG, while the Grin2a.RQ mutation affected the PFC. Further work is needed to elucidate the mechanisms through which these differential effects occur
Unexplained Acute Homonymous Hemianopia as a Presentation of Creutzfeldt–Jakob Disease.
Get PDFCreutzfeldt-Jakob disease (CJD) is the most common prion disorder that affects humans. The Heidenhain variant (HvCJD) of sporadic CJD (sCJD) is characterized by an array of often bizarre visual symptoms, which may precede progressive fatal neurodegeneration. Here, we describe a patient who presented with left homonymous hemianopia following a fall. Initial MRI and workup for vascular, autoimmune, infectious, paraneoplastic, or metabolic causes were unremarkable. Ophthalmological assessments suggested unexplained visual field loss with a possible functional overlay due to variability on examination. Over the following month, her condition deteriorated with progressive impaired awareness, involuntary movements, and finally akinetic mutism. Serial electroencephalography (EEG) demonstrated abnormalities consistent with significant encephalopathy with the development of periodic discharges. Further magnetic resonance imaging (MRI) showed parieto-occipital cortical ribboning. Altogether, the findings were consistent with a diagnosis of prion disease, more specifically, the Heidenhain or posterior variant of the condition. She died within six weeks of presentation. This report highlights the diagnostic challenges posed by HvCJD in patients with unexplained visual field loss, which can mimic a posterior circulation stroke or a functional neurological disorder. A normal MRI scan does not exclude CJD, especially in the early stages of the disease. Serial MRI and EEGs are needed in patients who present with unexplained and rapidly progressive encephalopathy with associated neurological symptoms. Early CSF analysis, including real-time quaking-induced conversion (RT-QuIC), should be considered in similar cases
Engineering in 2D violet phosphorus/PdSe2 van der Waals heterostructures for advanced optoelectronics
No full textTwo-dimensional (2D) van der Waals (vdWs) heterostructures have rapidly become promising platforms for advanced optoelectronic devices, mainly due to their extraordinary capability to control electronic and optical properties at atomically abrupt interfaces. However, realizing high-performance optoelectronics strongly relies on precise engineering at these interfaces to optimize charge carrier generation, transport, and extraction efficiencies. In this work, we present a comprehensive theoretical and experimental study of VP/PdSe 2 vdWs heterostructure targeting photodetector. Our findings indicate that VP/PdSe 2 vdWs heterostructures exhibit a type-I band alignment, enabling photodetection across the visible (VIS) to near infrared (NIR) spectral regions. By introducing graphene as a contact layer (Gr/VP/PdSe 2 ), we significantly enhanced device performance, achieving a remarkable responsivity of 111.3 AW −1 and an external quantum efficiency of 26001%, representing an enhancement of about three orders of magnitude compared to the bare VP/PdSe 2 devices. Moreover, the engineered photodetector demonstrated superior stability, maintaining consistent performance over 100 operational cycles, and an exceptionally fast photoresponse time of approximately 10 ms. Additionally, the device showed robust polarization-sensitive detection capabilities with an impressive dichroism ratio across a broad spectrum. This work paves the way to realize innovative 2D heterostructure for high-performance, multifunctional optoelectronic applications
Length-dependent quantum interference and high thermoelectric response ferrocene-modified OPE wires
No full textWe present a study of the length-dependent charge transport properties of a homologous series of oligo(phenylene–ethynylene) (OPE) molecular wires integrated with ferrocene units (Fe 1–Fe 5). Theoretical analysis reveals a coherent, length-dependent transport mechanism governed by quantum interference, with a distinct odd–even parity effect. Molecules with an odd number of ferrocene units exhibit a characteristic transmission dip within the HOMO–LUMO gap, a signature of destructive quantum interference (DQI), while even-numbered molecules show constructive quantum interference (CQI). This demonstrates that the interference behaviour is a holistic property of the full molecular length, not merely of the ferrocene core. The series exhibits efficient long-range tunneling, with a decay constant of β ≈ 1.1 nm−1 over lengths from 1.98 to 3.47 nm. Furthermore, these structures also possess high thermoelectric potential, with calculated Seebeck coefficients exceeding 250 µV K−1. The ability to switch between DQI and CQI states through molecular parity, combined with low conductance attenuation and high thermopower, establishes this ferrocene-OPE architecture as a highly promising platform for designing tuneable molecular electronic and energy conversion devices
Intersectional problems, intersectional solutions : A whole-of-community approach to co-produce local park-based physical activity interventions for ethnically diverse adolescent girls in a socio-economically deprived city in the United Kingdom
No full textParks are important spaces to engage with physical activity (PA) for adolescents, but challenges remain in transforming them into inclusive spaces for adolescent girls. Guided by intersectionality as a critical inquiry and praxis, with gendered understanding of Lefebvre’s notion of ‘the right to the city’, this paper presents a whole-of-community approach to co-produce local park-based PA interventions for ethnically diverse adolescent girls in socio-economically deprived urban areas in Bradford, United Kingdom (UK). We facilitated eight workshops, each was comprised of photo-elicitation discussion and feeding back research findings activities, with 37 adolescent girls, boys, and parents across two local parks – one was in a predominantly White British neighbourhood, and the other British Pakistani which was also co-developed with local adolescent girls. Three themes from the workshops are: 1) the limitations of focusing on park quality; 2) social support to improve adolescent girls’ confidence as active citizens, and; 3) multi-sited educational interventions to transform restrictive gender norms. Building on these themes, intervention ideas related to walking, youth workers, and Park Ambassadors are assembled into complex interventions called Girls and Their Parks (S-PARKS). We also call for greater use of a whole-of-community approach to intersectionality for co-producing PA interventions for adolescent girls
Missed opportunity : structural barriers to inclusion in EU Community-Led Local Development
No full textEuropean cities are still entrenched in social inequalities, exacerbated by the aftermath of the 2008 financial crisis and compounding austerity measures, the COVID-19 pandemic, and the ongoing Russia–Ukraine war. To mitigate inequalities, the European Union (EU) has promoted multilevel governance mechanisms, in particular Community-Led Local Development (CLLD), in order to empower local actors and foster inclusive growth. However, structural barriers continue to obstruct access to EU funds for the most marginalised communities. This article critically examines how urban development policies, shaped by neoliberal logics and the economisation of governance, have come to prioritise market efficiency over democratic participation and social equity. Drawing on qualitative research from seven European cities, we analyse how excessive bureaucracy, short-term project cycles, and the lack of genuine co-production systematically exclude grassroots actors and reinforce inequality. Our findings show that, despite an inclusive discourse, funding frameworks often privilege resource-rich organisations while further marginalising those most in need. We argue that these limitations are not incidental, but symptomatic of deeper governance structures that prioritise rapid, quantifiable outcomes over long-term, transformative social change. The paper calls for a recalibration of EU urban policy: one that centres co-creation, redistributes decision-making power, and meaningfully integrates community voices. Without such a shift, EU Cohesion Policy risks perpetuating the very exclusions it aims to resolve
Where do they come from and where do they go : understanding the relationship between deprivation and the geographical journeys of trainee doctors in England
No full textA relation of two and three-dimensional magnetic Weyl-Dirac operators
No full textBased on ideas mainly developed in Erdős and Solovej, 2001 and Aharonov and Casher, 1979, we consider a certain class of magnetic potentials, whose corresponding magnetic field is parallel to a particular class of Conformal Killing Fields, and the related magnetic Dirac operators. We deduce an equation interlacing these Dirac operators on R3 with a class of Dirac operators on R2. In the process, we introduce a one-parameter family of typically non-Hausdorff coordinate spaces, on members of which we map R3 using a Riemann-type submersion and show that standard Differential Geometry results hold for such spaces too