Line Orientation Adaptation: Local or Global?

Prolonged exposure to an oriented line shifts the perceived orientation of a subsequently observed line in the opposite direction, a phenomenon known as the tilt aftereffect (TAE). Here we consider whether the TAE for line stimuli is mediated by a mechanism that integrates the local parts of the line into a single global entity prior to the site of adaptation, or the result of the sum of local TAEs acting separately on the parts of the line. To test between these two alternatives we used the fact the TAE transfers almost completely across luminance contrast polarity [1]. We measured the TAE using adaptor and test lines that (1) either alternated in luminance polarity or were of a single polarity, and (2) either alternated in local orientation or were of a single orientation. We reasoned that if the TAE was agnostic to luminance polarity and was parts-based, we should obtain large TAEs using alternating-polarity adaptors with single-polarity tests. However we found that (i) TAEs using one-alternating-polarity adaptors with all-white tests were relatively small, increased slightly for two-alternating-polarity adaptors, and were largest with all-white or all-black adaptors. (ii) however TAEs were relatively large when the test was one-alternating polarity, irrespective of the adaptor type. (iii) The results with orientation closely mirrored those obtained with polarity with the difference that the TAE transfer across orthogonal orientations was weak. Taken together, our results demonstrate that the TAE for lines is mediated by a global shape mechanism that integrates the parts of lines into whole prior to the site of orientation adaptation. The asymmetry in the magnitude of TAE depending on whether the alternating-polarity lines was the adaptor or test can be explained by an imbalance in the population of neurons sensitive to 1(st)-and 2(nd)-order lines, with the 2(nd)-order lines being encoded by a subset of the mechanisms sensitive to 1(st)-order lines.This research was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) grant #RGPIN 121713-11 given to FK and Australian Research Council grant DP110101511 to JB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

A review of the National Performance Framework in light of the Stiglitz Report recommendations

Contents: A review of the National Performance Framework in light of the Stiglitz Report recommendations -- Annex 1: A national performance framework (Chapter 8 of 'Scottish budget spending review 2007') -- Annex 2: The capabilities approach (reproduced from Sen and Alkire in the Stiglitz Report, p. 151) -- Annex 3: The equality measurement frameworkThis report is based on the 'Report by the Commission on the Measurement of Economic Performance and Social Progress' (Stiglitz Report, 2009) and 'More than GDP : measuring what matters' (2011).The aim of this paper is to review the structure of the Scottish National Performance Framework (NPF) against the 12 recommendations set out in the Stiglitz Report.Publisher PD

Imagining circles: empirical data and a perceptual model for the arc-size illusion

An essential part of visual object recognition is the evaluation of the curvature of both an object's outline as well as the contours on its surface. We studied a striking illusion of visual curvature--the arc-size illusion (ASI)--to gain insight into the visual coding of curvature. In the ASI, short arcs are perceived as flatter (less curved) compared to longer arcs of the same radius. We investigated if and how the ASI depends on (i) the physical size of the stimulus and (ii) on the length of the arc. Our results show that perceived curvature monotonically increases with arc length up to an arc angle of about 60°, thereafter remaining constant and equal to the perceived curvature of a full circle. We investigated if the misjudgment of curvature in the ASI translates into predictable biases for three other perceptual tasks: (i) judging the position of the centre of circular arcs; (ii) judging if two circular arcs fall on the circumference of the same (invisible) circle and (iii) interpolating the position of a point on the circumference of a circle defined by two circular arcs. We found that the biases in all the above tasks were reliably predicted by the same bias mediating the ASI. We present a simple model, based on the central angle subtended by an arc, that captures the data for all tasks. Importantly, we argue that the ASI and related biases are a consequence of the fact that an object's curvature is perceived as constant with viewing distance, in other words is perceptually scale invariant

Is bigger better for primary care groups and trusts?

SIGLEAvailable from British Library Document Supply Centre-DSC:m01/16032 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Facial expression aftereffect revealed by adaption to emotion-invisible dynamic bubbled faces

Visual adaptation is a powerful tool to probe the short-term plasticity of the visual system. Adapting to local features such as the oriented lines can distort our judgment of subsequently presented lines, the tilt aftereffect. The tilt aftereffect is believed to be processed at the low-level of the visual cortex, such as V1. Adaptation to faces, on the other hand, can produce significant aftereffects in high-level traits such as identity, expression, and ethnicity. However, whether face adaptation necessitate awareness of face features is debatable. In the current study, we investigated whether facial expression aftereffects (FEAE) can be generated by partially visible faces. We first generated partially visible faces using the bubbles technique, in which the face was seen through randomly positioned circular apertures, and selected the bubbled faces for which the subjects were unable to identify happy or sad expressions. When the subjects adapted to static displays of these partial faces, no significant FEAE was found. However, when the subjects adapted to a dynamic video display of a series of different partial faces, a significant FEAE was observed. In both conditions, subjects could not identify facial expression in the individual adapting faces. These results suggest that our visual system is able to integrate unrecognizable partial faces over a short period of time and that the integrated percept affects our judgment on subsequently presented faces. We conclude that FEAE can be generated by partial face with little facial expression cues, implying that our cognitive system fills-in the missing parts during adaptation, or the subcortical structures are activated by the bubbled faces without conscious recognition of emotion during adaptation

The distribution of supermassive black holes in the nuclei of nearby galaxies

The growth of supermassive black holes by merging and accretion in hierarchical models of galaxy formation is studied by means of Monte Carlo simulations. A tight linear relation between masses of black holes and masses of bulges arises if if the mass accreted by supermassive black holes scales linearly with the mass forming stars and if the redshift evolution of mass accretion tracks closely that of star formation. Differences in redshift evolution between black hole accretion and star formation introduce considerable scatter in this relation. A non-linear relation between black hole accretion and star formation results in a non-linear relation between masses of remnant black holes and masses of bulges. The relation of black hole mass to bulge luminosity obseved in nearby galaxies and its scatter are reproduced reasonably well by models in which black hole accretion and star formation are linearly related but do not track each other in redshift. This suggests that a common mechanism determines the efficiency for black hole accretion and the efficiency for star formation, especially for bright bulges.Comment: 6 pages, 3 figures, submitted to MNRA

Can grey ravens fly? Beyond Frayling's categories

This paper analyses the effect of Christopher Frayling's (1993) categorisation of artistic research ‘research into art and design, research through art and design and research for art and design’ on the debate surrounding the efficacy of studio-based artistic research as being valid within the university. James Elkins (2009:128) describes this as ‘the incommensurability of studio art production and university life’. Through an exploration of the positive and negative responses to Frayling this paper seeks to explore the influence that these initial definitions have come to have on framing the scope of the debate. The paper presents a range of responses and analyses them and focuses especially on the alternative frameworks that have been suggested and examines why they have so far not created a coherent and uncontested frame-work for practice-led research in the art and design field especially in relation to fine art

The Next Act: Examining the Role of Theatre of Commitment and Human Rights in Post-democratic South Africa

The paper explores the role of theatre of commitment in advancing human rights in post-democratic South Africa. The notion of the theatre of commitment implies a theatre that has abandoned literary ends, to serve a political or social program or set of beliefs. The post-democratic South Africa is an antithesis of the Apartheid dispensation, human rights state whose construction is based solely on the pursuit of human rights norms. However, South Africa has not been a panacea of human rights as it has envisioned to be, given the socioeconomic inequalities of the past. Nowhere have these past inequalities shown themselves, than in the post-democratic tragic events of the Marikana Massacre on 16 August 2012, when the South African Police Service (SAPS) fired live ammunition into a crowd, killing 34 mine workers and seriously wounding 78. Cumulative the massacre claimed 47 lives, 34 mine workers and ten others who were killed by the protesting mineworkers, including two policemen and two security guards, while three died after the strike. The Life Esidimeni tragedy, occurred between 1 October 2015 and 31 June 2016 when 144 mentally ill patients died while being relocated from a private healthcare facility called Life Esidimeni (A place of dignity) to ill-equipped and short-staffed facilities around Johannesburg. The paper will explore the extent to which the theatricalisation of these two tragic events, demonstrated a cause committed to human rights as the political-moral idea of time on which became the foundation the post democratic South Africa a human rights state. This will be done by an in-depth analysis of Aubrey Sekhabi’s Marikana the Musical (2017) and Siyabonga Mdubeki’s Isililo (2020) which are two theatrical productions (play texts) that emanated from the two tragic events

Investigating penetrance of rare genetic variants using population cohorts

The same genetic variant found in different individuals can cause a spectrum of phenotypes, with some individuals showing no signs of any clinical illness, and some displaying severe illness. Variants that cause this can be said to show incomplete penetrance, where the related genotype either causes clinical disease or not, or they can be said to display variable expressivity, in which the clinical symptoms can vary across a spectrum. Incomplete penetrance and variable expressivity are both thought to be influenced by a large number of factors, including genetic modifiers, epigenetics, and environmental factors. Many thousands of genetic variants have been identified as causal of monogenic disorders, mostly determined through small clinical studies, and thus the penetrance and expressivity of these variants may be overestimated when compared to their effect in the general population. With the wealth of population cohort data currently available, the penetrance and expressivity of such genetic variants can be investigated across a much wider contingent, potentially helping to reclassify variants that were previously thought to be completely penetrant. This thesis aims to investigate the penetrance and expressivity of rare genetic variants in large population cohorts, and to potentially identify any genetic modifiers that could also affect the phenotypic effect of these variants, including the presence of other rare variants, and the aggregation of small effect common variants. We show that putatively damaging variants in a large number of genes are present at a higher rate than previously expected in healthy population cohorts. Furthermore, we show that as an aggregate, individuals who carry one of these variants have sub-clinical phenotypes related to the traits seen in clinical disease cases with variants in similar genes. We also show that the penetrance and expressivity of these rare variants can be modified by the presence of other rare variants in similar genes, and through common genetic variant, aggregated as polygenic scores. We then investigate methods of identifying rare non-coding variants that could be potential genetic modifiers

AY-­‐WB phytoplasma manipulations of host and non-­‐host leafhopper interactions

Hempitera. In plant hosts, phytoplasmas induce physiological changes and in both hosts modulate plant-­‐insect interactions. Previously, interactions have been examined with both hosts infected with phytoplasmas. Thus, it is unclear which organism the effect stems from or how phytoplasmas facilitate changes. To investigate phytoplasma manipulations of insect-­‐plant interactions, the model Arabidopsis thaliana was used together with the fully sequenced Aster Yellows phytoplasma strain Witches’ Broom (AY-­‐WB) and vector leafhopper Macrosteles quadrilineatus. I demonstrate possibility to differentiate effects of phytoplasma infection within plant and within insect hosts. To assess root cause of changes, AY-­‐WB secreted effector proteins were examined, their roles within plants, and in manipulations of vector fecundity. One of the 56 secreted AY-­‐WB proteins (SAPs) identified, SAP11, carries a nuclear localization signal and accumulates in plant cell nuclei (Bai et al. 2009). SAP11 is shown to reduce production of plant defense hormone jasmonic acid (Sugio et al. 2011). Stable expression of SAP11 and 3 other SAPs in Arabidopsis increase fecundity of M. quadrilineatus. In addition, phytoplasmas are known to affect non-­‐host insect-­‐plant interactions. Using the same approach, I demonstrate D. maidis survives and produces nymphs only on AY-­‐WB-­‐infected Arabidopsis. Furthermore, I show that whilst SAP11 has no effect on D. maidis survival, 3 other SAPs increase D. maidis survival and oviposition. These data suggest phytoplasmas utilize a suite of effector proteins to manipulate both host and non-­‐host insect-­‐plant interactions. Thus, AY-­‐ WB effector functions extend beyond direct interaction with plant hosts; they stimulate generation of insect vectors, and increase chance of uptake by novel insect hosts. This project highlights the value of using a model system in studying phytoplasma manipulation of their hosts and gives insight into development of evolutionary associations between phytoplasmas and vectors