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Contour integration in the parafovea and the near periphery:Testing the association field account
Get PDFIt is essential for object recognition that visual information is appropriately combined. To explain stages of perceptual organisation that group elements into contours, the concept of association fields has been invoked. Local elements within the boundaries of an association field are grouped to give rise to the percept of a contour if they are appropriately aligned, reasonably similar and close. However, the size of this spatial window remains unclear, as well as how this changes with visual field location. To address this, we studied the combined influence of eccentricity and inter-element spacing on contour detection. Our findings indicate a clear difference in the processing of contours between the parafovea and the periphery. Contour integration in parafoveal regions is efficient and highly stable across a wide range of inter-element spacings and levels of orientation noise. In the periphery, efficient integration is only observed for elements close enough to fall within adjacent receptive fields, while increased inter-element spacings and orientation changes lead to a failure of contour integration. We conclude that two distinct mechanisms underlie contour integration, each with its own spatial extent and tolerance to noise - with the efficient, association-field like mechanism being a characteristic of central vision
Between Feast and Famine:Food, Health, and the History of Ghana's Long Twentieth Century
Get PDFGhana’s twentieth century was one of dramatic political, economic, and environmental change. Sparked initially by the impositions of colonial rule, these transformations had significant, if rarely uniform, repercussions for the determinants of good and bad nutrition. All across this new and uneven polity, food production, domestic reproduction, gender relations, and food cultures underwent radical and rapid change. This volatile national history was matched only by the scientific instability of nutritional medicine during these same years. Moving between the dry Northern savannah, the mineral-rich and food-secure Southern rainforest, and the youthful, ever-expanding cities, Between Feast and Famine is a comparative history of nutrition in Ghana since the end of the nineteenth century. At the heart of this story is an analysis of how an uneven capitalist transformation variously affected the lives of women and children. It traces the change from sporadic periods of hunger in the nineteenth and early twentieth centuries, through epidemics of childhood malnutrition during the twentieth century, and into emergent epidemics of diet-related non-communicable disease in the twenty-first century. Employing a novel, critical approach to historical epidemiology, John Nott argues that detailing the co-production of science and its subjects in the past is essential for understanding and improving health in the present
A Lagrangian view of flame-vortex interaction during turbulent side-wall quenching using high-speed OH-LIF and PIV
Get PDFFlame-vortex interactions have been suggested to play an important role in flame-wall interactions (FWI). This study presents an experimental investigation of flame-vortex interactions and their influence on flame quenching. Experiments are conducted in a side-wall quenching (SWQ) burner with V-flame configuration. Simultaneous high-resolution particle image velocimetry and OH laser induced fluorescence are conducted to study the flame-flow-wall dynamics under turbulent FWI conditions. Reynolds decomposition is used to provide a Lagrangian reference frame relative to the ensemble-mean velocity field to visualize the evolution of coherent turbulent vortical structures. These vortical flow structures are correlated with regions of elevated swirling strength in the instantaneous velocity field. Three classifications of flame-vortex interaction are identified. One of these classifications emulates a flame-vortex interaction mechanism recently proposed in the literature. This particular flame-vortex interaction reveals a vortex that emanates from the burnt gas and moves quickly towards the wall. The vortex impacts the wall, where local flame quenching occurs and the flame transitions from a head-on quenching (HOQ) to a SWQ flame topology. After quenching, the vortex remains next to the wall and directly above the flame tip as the flame progresses downstream. Each flame quenching event observed in the data exhibits this flame-vortex interaction. This work evaluates the kinematic attributes of the vortex and reveals the tendency of the vortex to push the flame closer to the wall, where the flame experiences flame quenching. Alongside previous DNS studies, this work shows that flame-vortex interactions are phenomenological features that influence flame quenching, as well as heat and mass transport near the wall
The potential role of mifepristone in breast cancer prevention: beyond medical abortion
Get PDFBreast cancer is the leading cause of cancer-related deaths among women globally. Yet, current management strategies emphasise detection and treatment over primary prevention. For groups at high risk of breast cancer, such as carriers of BRCA1 or BRCA2 pathogenic variants, salpingo-oophorectomy and mastectomy are risk-reducing surgical options, but these approaches affect quality of life and evidence for a mortality benefit is sparse. Non-surgical treatments, such as selective oestrogen receptor modulators, have low efficacy against breast cancers with poor prognosis (eg, triple-negative cancers), and toxicity can often lead to poor adherence. Emerging evidence indicates that progesterone plays a part in breast carcinogenesis, particularly in carriers of BRCA1 pathogenic variants. Mifepristone, a selective progesterone receptor modulator, has shown potential to reduce breast epithelial proliferation. However, the association of this drug with medical abortion, besides long-standing availability and patent restrictions, has hindered its development for breast cancer prevention. Regulatory, political, and legal barriers, along with minimal pharmaceutical investment, have further restricted research. Collaborative efforts are needed to accelerate research on mifepristone as a non-surgical risk-reducing option. Overcoming current barriers is essential to expand prevention strategies, particularly for women at high risk of breast cancer worldwide
External validation of paediatric pneumonia and bronchiolitis risk scores to predict mortality in children hospitalized in Kenya:a retrospective cohort study
Get PDFBackgroundAcute lower respiratory tract infections (ALRIs) are a leading cause of paediatric mortality in low- and middle-income countries. In recent years, substantial research has been done to enhance risk stratification of children presenting with ALRIs, in a bid to improve health outcomes in resource-limited settings. We sought to analyse the performance of several paediatric ALRI risk scores in the prediction of mortality among children hospitalised with ALRIs in Kenya.MethodsWe retrospectively analysed the data of 2182 children aged 2-24 months who were admitted to Kilifi County Referral Hospital, Kenya with severe ALRIs between January 2015 and December 2024. We evaluated the performance of 6 ALRI risk scores (RISC (HIV-Negative), mRISC, RISC-Malawi, PERCH, PREPARE, ReSVinet) in this population. Additionally, we created and evaluated a modified version of the ReSVinet score by including nutrition status. Discrimination was assessed using the area under the receiver operating characteristic curve (AUROC).ResultsThe mid-upper arm circumference (MUAC) version of the RISC-Malawi score showed the highest discrimination for the outcome of in-hospital mortality (AUROC: 0.83, 95% CI: (0.79 – 0.86)), whilst all other scores showed acceptable discrimination (AUROC: 0.70 – 0.79). The modification of ReSVinet to include nutrition status significantly improved its AUROC from 0.72 to 0.79.ConclusionAll risk scores showed at least fair performance in the prediction of in-hospital mortality within our dataset. The RISC-Malawi (MUAC) score appears to be the most promising candidate for future implementation, however further research is needed to evaluate the calibration, feasibility and clinical utility of these scores.<br/
Who considers migrants' competence important?:The role of political ideology
Get PDFEstablished theories have recognised competence as a fundamental dimension in social judgements of migrants, but it remains unclear who particularly values competence in this context. In an experimental study with British participants (N = 510), we examined how majority group members' political ideology influences their judgements about the importance of migrant competence and how migrant warmth moderates this relationship. We also tested competitive and dangerous worldviews as potential mediators of this process. The results showed that conservatives placed greater importance on migrant competence than liberals, particularly when the migrant group was described as warm. Additionally, while conservative ideology predicted a greater perceived importance of migrant competence through heightened competitive and dangerous worldviews, migrant warmth did not moderate these indirect effects. These findings enhance our understanding of when and why majority group members value migrant groups' competence and highlight the complexity of ideological motivations in intergroup judgements
Land projected to be below annual flood level in 2050:A brief cultural history
Get PDFThis article begins with the radical destabilization of the coastal map of Britain represented by Climate Central’s “Coastal Risk Screening Tool”, which projects extensive coastal flooding in the coming decades. Paying particular attention to the Solway Firth, an inlet on the west of the British mainland, it then turns to the knowledge production of the eighteenth and early nineteenth centuries, including surveys, maps, travel writing and novels. It does so in order to underline that what we are experiencing two centuries later is not precisely the unmooring of a stable sense of place, but rather a new, colossally extended species of instability
Functional traits in arborescent Cactaceae: a guideline for their measurement
Get PDFThe need to understand the impacts of global change on ecosystems has driven interest in studying functional traits, which represent morphological, physiological, or phenological adaptations that determine the ecological performance of organisms. Although standardized methods exist for assessing functional traits in woody and herbaceous plants, protocols for arborescent cacti are still scarce. Cactaceae is a tropical American plant family that reaches high abundance in tropical dry ecosystems and encompasses a great diversity of form and size. Cacti perform fundamental ecosystem functions, are on the list of the most endangered plants globally and represent economically-impactful invasive species outside of the Americas. Here, we propose protocols to measure 12 functional traits in cacti, which are grouped into structural (two traits), morphological (seven traits), hydraulic–mechanical (two traits) and biophysical (one trait) categories, so as to complement ecological studies of plants and improve the understanding of their life cycle and the main environmental challenges faced by cacti
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