32151 research outputs found
Sort by
Sensorimotor adaptation reveals systematic biases in 3D perception
Get PDFFunding: This research was supported by the National Science Foundation under Grant No.2120610.The existence of biases in visual perception and their impact on visually guided actions has long been a fundamental yet unresolved question. Evidence revealing perceptual or visuomotor biases has typically been disregarded because such biases in spatial judgments can often be attributed to experimental measurement confounds. To resolve this controversy, we leveraged the visuomotor system’s adaptation mechanism — triggered only by a discrepancy between visual estimates and sensory feedback — to directly indicate whether systematic errors in perceptual and visuomotor spatial judgments exist. To resolve this controversy, we leveraged the adaptive mechanisms of the visuomotor system to directly reveal whether systematic biases or errors in perceptual and visuomotor spatial judgments exist. In a within-subject study (N=24), participants grasped a virtual 3D object with varying numbers of depth cues (single vs. multiple) while receiving haptic feedback. The resulting visuomotor adaptations and aftereffects demonstrated that the planned grip size, determined by the visually perceived depth of the object, was consistently overestimated. This overestimation intensified when multiple cues were present, despite no actual change in physical depth. These findings conclusively confirm the presence of inherent biases in visual estimates for both perception and action, and highlight the potential use of visuomotor adaptation as a novel tool for understanding perceptual biases.Peer reviewe
In time, we will simply disappear : racial demographic shift undermines privileged group members' support for marginalized social groups via collective angst
Get PDFFunding: The presented work was partially supported by Social Sciences and Humanities Research Council Insight Grant (Canada) to the second author (#435-2012-1135).The racial demographic shift occurring in many Western countries provides a unique context to study the reactions of a high-power group (White people) to the potential loss of their privileged position in society. Three experiments (N = 77, N = 302, N = 555) conducted in Canada, the US, and the UK showed that White people who are reminded about the ongoing demographic changes and who see race relations as a zero-sum game whereby any gains by minorities must come at the expense of the majority, experience stronger collective angst and, to a lesser extent, fear (but not anger). In turn, collective angst, but not the other negative group-based emotions, fuels their motivation to protect the existing intergroup hierarchy by withdrawing support for progressive social movements and increases anti-immigration sentiments. Downregulating the existential threat experienced by White majorities in the face of a racial demographic shift may be one way to reduce acrimonious behavioral intentions aimed at preserving their place in the social hierarchy.Peer reviewe
Diisopropyl (E)-(1-hydroxy-3-phenylallyl)phosphonate
Get PDFWe report the synthesis and the molecular structure as determined by single-crystal X-ray diffraction of diisopropyl (E)-(1-hydroxy-3-phenylallyl)phosphonate. The compound was fully characterised by 1H, 13C, and 31P NMR spectroscopy, IR spectroscopy, and Mass Spectrometry.Peer reviewe
SAM-AMP lyases in type III CRISPR defence
Get PDFFunding: This work was supported by a grant from the Biotechnology and Biological Sciences Research Council (Grant REF BB/T004789/1 to MFW and TMG) and a European Research Council Advanced Grant (Grant REF 101018608 to MFW).Type III CRISPR systems detect non-self RNA and activate the enzymatic Cas10 subunit, which generates nucleotide second messengers for activation of ancillary effectors. Although most signal via cyclic oligoadenylate, an alternative class of signalling molecule SAM-AMP, formed by conjugating ATP and S-adenosylmethionine, was described recently. SAM-AMP activates a trans-membrane effector of the CorA magnesium transporter family to provide anti-phage defence. Intriguingly, immunity also requires SAM-AMP degradation by means of a specialized CRISPR-encoded NrN family phosphodiesterase in Bacteroides fragilis. In Clostridium botulinum, the nrn gene is replaced by a gene encoding a SAM-AMP lyase. Here, we investigate the structure and activity of C. botulinum SAM-AMP lyase, which can substitute for the nrn gene to provide CorA-mediated immunity in Escherichia coli. The structure of SAM-AMP lyase bound to its reaction product 5′-methylthioadenosine-AMP reveals key details of substrate binding and turnover by this PII superfamily protein. Bioinformatic analysis revealed a phage-encoded SAM-AMP lyase that degrades SAM-AMP efficiently in vitro, consistent with an anti-CRISPR function.Peer reviewe
Evidence of self-care tooling and phylogenetic modeling reveal parrot tool use is not rare
Get PDFPutatively rare behaviors like tool use are difficult to study because absence of evidence can arise from a species' inability to produce the behavior or from insufficient research. We combine data from digital platforms and phylogenetic modeling to estimate rates of tool use in parrots. Videos on YouTube revealed novel instances of self-care tooling in 17 parrot species, more than doubling the number of tool-using parrots from 11 (3%) to 28 (7%). Phylogenetic modeling suggests 11-17% of extant parrot species may be capable of tool use and identifies likely candidates. These discoveries impact our understanding of the evolution of tool use in parrots, revealing associations with relative brain size and feeding generalism and indicating likely ancestral tool use in several genera. Our findings challenge the assumption that current sampling efforts fully capture the distribution of putatively rare animal behaviors and offer a fruitful approach for investigating other rare behaviors.Peer reviewe
Assouad spectrum of Gatzouras-Lalley carpets
Get PDFFunding: AB, JMF and IK were supported by a Leverhulme Trust Research Project Grant (RPG-2019-034) at the University of St Andrews. AB was also supported by an EPSRC New Investigators Award (EP/W003880/1) while at Loughborough University. AR was supported by EPSRC Grant EP/V520123/1 and the Natural Sciences and Engineering Research Council of Canada fellowship CGS-D 567958-2022. IK was also supported by the European Research Council Marie Skłodowska-Curie Actions Postdoctoral Fellowship #101109013.We study the fine local scaling properties of a class of self-affine fractal sets called Gatzouras–Lalley carpets. More precisely, we establish a formula for the Assouad spectrum of all Gatzouras–Lalley carpets as the concave conjugate of an explicit piecewise-analytic function combined with a simple parameter change. Our formula implies a number of novel properties for the Assouad spectrum not previously observed for dynamically invariant sets; in particular, the Assouad spectrum can be a non-trivial differentiable function on the entire domain (0, 1) and can be strictly concave on open intervals. Our proof introduces a general framework for covering arguments using techniques developed in the context of multifractal analysis, including the method of types from large deviations theory and Lagrange duality from optimisation theory.Peer reviewe
ShareTrait : towards interoperable and reusable individual trait-based data in ectotherms
Get PDFFunding: The ShareTrait project has been supported by the Netherlands Organisation for Scientific Research through the Open Science programme (OSF 203.001.015; OSF23.1.042). We are grateful for individual research support from the Alexander von Humboldt Foundation, Research Grants Council of Hong Kong, Research Foundation—Flanders (FWO), Israel Science Foundation, Agencia National de Investigation y Desarrollo (ANID), Hudson River Foundation and The Nature Conservancy, National Biodiversity Future Centre and Fonds National de Recherche Scientifique. We acknowledge support by the Open Access publication fund of Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung. We also acknowledge Manuel Díaz, Jorge Henríquez, Thamara Matamala and Katherine Espinoza for their support during the field campaign associated with one dataset used in this study. Open Access funding enabled and organized by Projekt DEAL.1. More and more data on species traits are being collected and made openly available. Despite these efforts, effective syntheses of trait data to comprehend how species respond to and affect their environment are hampered by inadequate standards for publishing the data and the associated metadata, which limits the interoperability and reuse of data across studies. 2. We have developed ShareTrait (https://sharetrait.org/), a novel initiative that consolidates individual-level trait data and associated metadata in an interoperable and reusable format, enabling standardised and integrated use. As a proof-of-concept, we initially focus on three core traits of ectotherms: metabolic rate, development time and fecundity. These traits, measurable in almost all animals, are fundamental to an organism’s overall fitness. 3. ShareTrait enables researchers to share their (meta)data with the research community. To date, researchers from diverse fields have contributed 28,692 individual-level data records to ShareTrait. These records originated from 45 datasets and are just the tip of the iceberg of existing data, highlighting the potential of ShareTrait to be a valuable community resource for meta-analyses and comparative approaches. 4. Future directions of ShareTrait will focus on accumulating more records, expanding to cover more traits, including those measurable at the population level, and partnering with journals in relevant fields (ecology, physiology, evolution) to make sharing standardised trait data part of the standard publication process. 5. We envision ShareTrait, along with its digital infrastructure and comprehensive metadata, to be a catalyst for collating trait data across species. ShareTrait can streamline research efforts, minimise duplication and empower researchers to explore patterns and broader ecological, evolutionary and physiological questions among taxa (e.g. via meta-analyses and comparative approaches). This way, ShareTrait will unlock new frontiers in trait-based approaches, enhancing our understanding of species–environment relationships.Peer reviewe
Evaluating the effectiveness of the Arclight : a compact solar-powered low-cost direct ophthalmoscope
Get PDFPURPOSE: The purpose of this study is to assess the accuracy and utility of the Arclight device, a frugal direct ophthalmoscope, in evaluating the cup-to-disc ratio (CDR) by a nonophthalmologist examiner in comparison to an expert ophthalmologist using a range of standard diagnostic tools. METHODS: A prospective study was conducted with 108 participants (211 eyes) at ophthalmology clinics associated with the University of California, Irvine. A medical student (naïve nonophthalmologist examiner [NNOE]) performed fundus examinations using the Arclight whereas a pediatric ophthalmologist conducted gold standard evaluations with a combination of direct ophthalmoscopy, indirect ophthalmoscopy, and/or slit-lamp examination. Training for the NNOE included didactic sessions on using the Arclight for fundal “red” reflex testing and fundus assessment including CDR estimation. Data collected included CDR values, ease of use (EOU, rated on a 5-point scale), and examination time. Bland–Altman analysis compared student and ophthalmologist measurements, with stratified analyses exploring performance across demographics, including age, sex, iris color, and dilation status. RESULTS: Examinations with the Arclight were successful in 76.8% (162/211) of cases. Mean CDR values by the student (0.325) aligned closely with those by the ophthalmologist (0.331, P = 0.27), with 95% agreement within ± 0.17. The Arclight performed well across most groups, with highest EOU and shortest examination times in dilated eyes. As expected, challenges were noted in younger children and those with nondilated pupils. CONCLUSION: The Arclight is a reliable, affordable, and user-friendly tool for fundoscopic examinations. Its low cost and portability make it ideal for low- and middle-income countries, supporting global efforts to reduce preventable blindness. Targeted training and technique adjustments could enhance its performance in specific populations.Peer reviewe
Fertility variation in China from spatial and life course perspective
No full textChina is experiencing a fertility transition with a rapid fertility decline and continued regional fertility variation. The fertility variation at the aggregated level is the accumulation of individuals’ fertility behaviours; individuals living in different regions may have different childbearing behaviours.
There is a large literature on fertility trends and patterns in China. However, there are also significant gaps in the literature. First, although previous studies have investigated spatial variation in fertility in China, none have provided a satisfactory account of how population composition, context, and migration influence fertility variation at the regional level. Second, no previous analysis has examined the regional variation in the individuals’ childbearing behaviour, and how the context influences the individuals’ fertility behaviour.
This PhD thesis investigates the variation in fertility level and change, the timing and levels of individuals’ births, as well as the impact of population composition, context, and migration on fertility, from both spatial and life course perspectives in China. Advanced quantitative methods, including spatial regression models, event history analysis, and multilevel modelling, are used to analyse data from population censuses, statistical yearbooks, and China Family Panel Studies (CFPS).
The results show that there is spatial variation in fertility level and fertility change, and that both population composition and context in the same county and also its neighbouring counties influence the fertility in a given county. From the life course perspective, the study shows regional variation in women’s transition from first to second birth. Contextual factors such as family planning policy, traditional fertility culture, economic development, and urbanisation influence women’s transition to second birth in China. This thesis advances the understanding of the patterns of fertility transition and behaviours in China and emphasises the importance of context in fertility analyses in low-fertility societies
Learning algorithms for identification of whisky using portable Raman spectroscopy
Get PDFFunding: The authors acknowledge funding support from an ARC Laureate Fellowship FL210100099, an NHMRC Ideas Grant APP2003786, the European Union’s Horizon 2020 research and innovation programme “Proscope” (871212), funding through the Innovation Connections program partnering with Beston Global Foods Pty Ltd and from the University of St Andrews Impact and Innovation Fund.Reliable identification of high-value products such as whisky is an increasingly important area, as issues such as brand substitution (i.e. fraudulent products) and quality control are critical to the industry. We have examined a range of machine learning algorithms and interfaced them directly with a portable Raman spectroscopy device to both identify and characterize the ethanol/methanol concentrations of commercial whisky samples. We demonstrate that machine learning models can achieve over 99% accuracy in brand identification across twenty-eight commercial samples. To demonstrate the flexibility of this approach we utilised the same samples and algorithms to quantify ethanol concentrations, as well as measuring methanol levels in spiked whisky samples. Our machine learning techniques are then combined with a through-the-bottle method to perform spectral analysis and identification without requiring the sample to be decanted from the original container, showing the practical potential of this approach to the detection of counterfeit or adulterated spirits and other high value liquid samples.Peer reviewe
Access Repository Dashboard
Do you manage St Andrews Research Repository? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!