178 research outputs found

    Experience, action and affordance perception

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    The aim for this thesis is to motivate, critically evaluate and defend the claim that subjects are able to consciously perceive the affordances of objects. I will present my protagonist, the ‘Conscious Affordance Theorist’, with what are two main obstacles to this claim. The first of these is that affordance perception correctly understood refers only to a kind of subpersonal visual processing, and not to a kind of conscious visual experience. I claim that this results in an explanatory gap at the level of intentional action, which in order to correct we need to redefine the notion of affordance perception to include conscious as well as subpersonal affordance perception. Precisely, I claim that ‘affordance awareness’ has a crucial epistemological role to play, and that subjects must be able to consciously experience affordances in order to gain this awareness. In answer to this claim, I supplement the objection that affordance perception is defined as subpersonal perception to include the claim that any awareness subjects have of the affordances of objects they visually experience is due to them having thoughts about those affordances, and not visual experience of them. I then consider the Conscious Affordance Theorist’s response to this supplemented account. The second obstacle is the claim that conscious visual affordance perception is an impossible notion given that affordances are dispositional properties, and the dispositional properties of objects cannot be ‘seen’. In facing this objection I look to the supporting claims and motivations that lie behind it, in order to find a way for the Conscious Affordance Theorist to challenge its central claim that affordances cannot be seen. I end this thesis with an account of the Conscious Affordance Theorist’s own positive position, and a consideration of how his account has the ability to provide for conscious affordance perception in the case of non-human animals

    Experience, action and affordance perception

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    The aim for this thesis is to motivate, critically evaluate and defend the claim that subjects are able to consciously perceive the affordances of objects. I will present my protagonist, the ‘Conscious Affordance Theorist’, with what are two main obstacles to this claim. The first of these is that affordance perception correctly understood refers only to a kind of subpersonal visual processing, and not to a kind of conscious visual experience. I claim that this results in an explanatory gap at the level of intentional action, which in order to correct we need to redefine the notion of affordance perception to include conscious as well as subpersonal affordance perception. Precisely, I claim that ‘affordance awareness’ has a crucial epistemological role to play, and that subjects must be able to consciously experience affordances in order to gain this awareness. In answer to this claim, I supplement the objection that affordance perception is defined as subpersonal perception to include the claim that any awareness subjects have of the affordances of objects they visually experience is due to them having thoughts about those affordances, and not visual experience of them. I then consider the Conscious Affordance Theorist’s response to this supplemented account. The second obstacle is the claim that conscious visual affordance perception is an impossible notion given that affordances are dispositional properties, and the dispositional properties of objects cannot be ‘seen’. In facing this objection I look to the supporting claims and motivations that lie behind it, in order to find a way for the Conscious Affordance Theorist to challenge its central claim that affordances cannot be seen. I end this thesis with an account of the Conscious Affordance Theorist’s own positive position, and a consideration of how his account has the ability to provide for conscious affordance perception in the case of non-human animals.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Performance test of QU-fitting in cosmic magnetism study

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    QU-fitting is a standard model-fitting method to reconstruct distribution of magnetic fields and polarized intensity along a line of sight (LOS) from an observed polarization spectrum. In this paper, we examine the performance of QU-fitting by simulating observations of two polarized sources located along the same LOS, varying the widths of the sources and the gap between them in Faraday depth space, systematically. Markov Chain Monte Carlo (MCMC) approach is used to obtain the best-fit parameters for a fitting model, and Akaike and Bayesian Information Criteria (AIC and BIC, respectively) are adopted to select the best model from four fitting models. We find that the combination of MCMC and AIC/BIC works fairly well in model selection and estimation of model parameters in the cases where two sources have relatively small widths and a larger gap in Faraday depth space. On the other hand, when two sources have large width in Faraday depth space, MCMC chain tends to be trapped in a local maximum so that AIC/BIC cannot select a correct model. We discuss the causes and the tendency of the failure of QU-fitting and suggest a way to improve it.Comment: 8 pages, 9 figures, submitted to MNRA

    Dual ancestries and ecologies of the Late Glacial Palaeolithic in Britain

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    Genetic investigations of Upper Palaeolithic Europe have revealed a complex and transformative history of human population movements and ancestries, with evidence of several instances of genetic change across the European continent in the period following the Last Glacial Maximum (LGM). Concurrent with these genetic shifts, the post-LGM period is characterized by a series of significant climatic changes, population expansions and cultural diversification. Britain lies at the extreme northwest corner of post-LGM expansion and its earliest Late Glacial human occupation remains unclear. Here we present genetic data from Palaeolithic human individuals in the United Kingdom and the oldest human DNA thus far obtained from Britain or Ireland. We determine that a Late Upper Palaeolithic individual from Gough's Cave probably traced all its ancestry to Magdalenian-associated individuals closely related to those from sites such as El Mirón Cave, Spain, and Troisième Caverne in Goyet, Belgium. However, an individual from Kendrick's Cave shows no evidence of having ancestry related to the Gough’s Cave individual. Instead, the Kendrick’s Cave individual traces its ancestry to groups who expanded across Europe during the Late Glacial and are represented at sites such as Villabruna, Italy. Furthermore, the individuals differ not only in their genetic ancestry profiles but also in their mortuary practices and their diets and ecologies, as evidenced through stable isotope analyses. This finding mirrors patterns of dual genetic ancestry and admixture previously detected in Iberia but may suggest a more drastic genetic turnover in northwestern Europe than in the southwest

    Climate change, malaria and neglected tropical diseases: a scoping review

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    To explore the effects of climate change on malaria and 20 neglected tropical diseases (NTDs), and potential effect amelioration through mitigation and adaptation, we searched for papers published from January 2010 to October 2023. We descriptively synthesised extracted data. We analysed numbers of papers meeting our inclusion criteria by country and national disease burden, healthcare access and quality index (HAQI), as well as by climate vulnerability score. From 42 693 retrieved records, 1543 full-text papers were assessed. Of 511 papers meeting the inclusion criteria, 185 studied malaria, 181 dengue and chikungunya and 53 leishmaniasis; other NTDs were relatively understudied. Mitigation was considered in 174 papers (34%) and adaption strategies in 24 (5%). Amplitude and direction of effects of climate change on malaria and NTDs are likely to vary by disease and location, be non-linear and evolve over time. Available analyses do not allow confident prediction of the overall global impact of climate change on these diseases. For dengue and chikungunya and the group of non-vector-borne NTDs, the literature privileged consideration of current low-burden countries with a high HAQI. No leishmaniasis papers considered outcomes in East Africa. Comprehensive, collaborative and standardised modelling efforts are needed to better understand how climate change will directly and indirectly affect malaria and NTDs

    Prevalence of Salmonella in Stool During the Vaccine Impact on Diarrhea in Africa (VIDA) Study, 2015-2018.

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    BACKGROUND: Non-typhoidal Salmonella (NTS) is a common cause of gastroenteritis in young children, with limited data on NTS serovars and antimicrobial resistance in Africa. METHODS: We determined the prevalence of Salmonella spp. and frequency of antimicrobial resistance among serovars identified in stools of 0-59 month-old children with moderate-to-severe diarrhea (MSD) and controls enrolled in the Vaccine Impact on Diarrhea in Africa (VIDA) Study in The Gambia, Mali, and Kenya in 2015-2018, and compared with data from the Global Enteric Multicenter Study (GEMS; 2007-2010) and the GEMS-1A study (2011). Salmonella spp. was detected by quantitative real-time PCR (qPCR) and culture-based methods. Identification of serovars was determined by microbiological methods. RESULTS: By qPCR, the prevalence of Salmonella spp. among MSD cases was 4.0%, 1.6%, and 1.9% and among controls was 4.6%, 2.4%, and 1.6% in The Gambia, Mali, and Kenya, respectively, during VIDA. We observed year-to-year variation in serovar distribution and variation between sites. In Kenya, Salmonella enterica serovar Typhimurium decreased (78.1% to 23.1%; P < .001) among cases and controls from 2007 to 2018, whereas serogroup O:8 increased (8.7% to 38.5%; P = .04). In The Gambia, serogroup O:7 decreased from 2007 to 2018 (36.3% to 0%; P = .001) but S. enterica serovar Enteritidis increased during VIDA (2015 to 2018; 5.9% to 50%; P = .002). Only 4 Salmonella spp. were isolated in Mali during all 3 studies. Multidrug resistance was 33.9% in Kenya and 0.8% in The Gambia across all 3 studies. Ceftriaxone resistance was only observed in Kenya (2.3%); NTS isolates were susceptible to ciprofloxacin at all sites. CONCLUSIONS: Understanding variability in serovar distribution will be important for the future deployment of vaccines against salmonellosis in Africa

    Identifying educator behaviours for high quality verbal feedback in health professions education: literature review and expert refinement

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    Background Health professions education is characterised by work-based learning and relies on effective verbal feedback. However the literature reports problems in feedback practice, including lack of both learner engagement and explicit strategies for improving performance. It is not clear what constitutes high quality, learner-centred feedback or how educators can promote it. We hoped to enhance feedback in clinical practice by distinguishing the elements of an educator’s role in feedback considered to influence learner outcomes, then develop descriptions of observable educator behaviours that exemplify them. Methods An extensive literature review was conducted to identify i) information substantiating specific components of an educator’s role in feedback asserted to have an important influence on learner outcomes and ii) verbal feedback instruments in health professions education, that may describe important educator activities in effective feedback. This information was used to construct a list of elements thought to be important in effective feedback. Based on these elements, descriptions of observable educator behaviours that represent effective feedback were developed and refined during three rounds of a Delphi process and a face-to-face meeting with experts across the health professions and education. Results The review identified more than 170 relevant articles (involving health professions, education, psychology and business literature) and ten verbal feedback instruments in health professions education (plus modified versions). Eighteen distinct elements of an educator’s role in effective feedback were delineated. Twenty five descriptions of educator behaviours that align with the elements were ratified by the expert panel. Conclusions This research clarifies the distinct elements of an educator’s role in feedback considered to enhance learner outcomes. The corresponding set of observable educator behaviours aim to describe how an educator could engage, motivate and enable a learner to improve. This creates the foundation for developing a method to systematically evaluate the impact of verbal feedback on learner performance
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