City University London

About: City University London is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 5735 authors who have published 17285 publications receiving 453290 citations.

Clinical Validation of a Smartphone-Based Adapter for Optic Disc Imaging in Kenya.

Abstract: Importance Visualization and interpretation of the optic nerve and retina are essential parts of most physical examinations. Objective To design and validate a smartphone-based retinal adapter enabling image capture and remote grading of the retina. Design, Setting, and Participants This validation study compared the grading of optic nerves from smartphone images with those of a digital retinal camera. Both image sets were independently graded at Moorfields Eye Hospital Reading Centre. Nested within the 6-year follow-up (January 7, 2013, to March 12, 2014) of the Nakuru Eye Disease Cohort in Kenya, 1460 adults (2920 eyes) 55 years and older were recruited consecutively from the study. A subset of 100 optic disc images from both methods were further used to validate a grading app for the optic nerves. Data analysis was performed April 7 to April 12, 2015. Main Outcomes and Measures Vertical cup-disc ratio for each test was compared in terms of agreement (Bland-Altman and weighted κ) and test-retest variability. Results A total of 2152 optic nerve images were available from both methods (also 371 from the reference camera but not the smartphone, 170 from the smartphone but not the reference camera, and 227 from neither the reference camera nor the smartphone). Bland-Altman analysis revealed a mean difference of 0.02 (95% CI, −0.21 to 0.17) and a weighted κ coefficient of 0.69 (excellent agreement). The grades of an experienced retinal photographer were compared with those of a lay photographer (no health care experience before the study), and no observable difference in image acquisition quality was found. Conclusions and Relevance Nonclinical photographers using the low-cost smartphone adapter were able to acquire optic nerve images at a standard that enabled independent remote grading of the images comparable to those acquired using a desktop retinal camera operated by an ophthalmic assistant. The potential for task shifting and the detection of avoidable causes of blindness in the most at-risk communities makes this an attractive public health intervention.

Recognition memory, self-other source memory, and theory-of-mind in children with autism spectrum disorder

Abstract: This study investigated semantic and episodic memory in autism spectrum disorder (ASD), using a task which assessed recognition and self-other source memory. Children with ASD showed undiminished recognition memory but significantly diminished source memory, relative to age- and verbal ability-matched comparison children. Both children with and without ASD showed an “enactment effect”, demonstrating significantly better recognition and source memory for self-performed actions than other-person-performed actions. Within the comparison group, theory-of-mind (ToM) task performance was significantly correlated with source memory, specifically for other-person-performed actions (after statistically controlling for verbal ability). Within the ASD group, ToM task performance was not significantly correlated with source memory (after controlling for verbal ability). Possible explanations for these relations between source memory and ToM are considered.

Corporate social sustainability in supply chains: a thematic analysis of the literature

Abstract: This paper maps out different research strands using thematic analysis on the literature pertaining to large companies’ efforts on social sustainability in their supply chains. The data corpus for this thematic analysis is a broad sample of the literature with articles from different journals and employing different research methodologies. Each of the high-level themes is identified at a level high enough to apply to research into not only social but also economic or environmental sustainability. These eight themes – stakeholder pressure; governance; contingencies; practices; partnerships; barriers and enablers; performance; and optimisation for performance improvement and trade-off – are then woven into a thematic map. We call this map the ‘4P’ model as it suggests that pressure and partnerships influence practices, which in turn impact performance. Researchers can use this thematic classification not only to position their research within the social sustainability literature but also to integrate resear...

Traintracks through Calabi-Yau Manifolds: Scattering Amplitudes beyond Elliptic Polylogarithms

Abstract: We describe a family of finite, four-dimensional, L-loop Feynman integrals that involve weight-(L+1) hyperlogarithms integrated over (L−1)-dimensional elliptically fibered varieties we conjecture to be Calabi-Yau manifolds. At three loops, we identify the relevant K3 explicitly and we provide strong evidence that the four-loop integral involves a Calabi-Yau threefold. These integrals are necessary for the representation of amplitudes in many theories—from massless φ4 theory to integrable theories including maximally supersymmetric Yang-Mills theory in the planar limit—a fact we demonstrate.