Finite distance corrections to the light deflection in a gravitational field with a plasma medium

The aim of the present work is twofold: first, we present general remarks about the application of recent procedures to compute the deflection angle in spherically symmetric and asymptotically flat spacetimes, taking into account finite distance corrections based on the Gauss-Bonnet theorem. Second, and as the main part of our work, we apply this powerful technique to compute corrections to the deflection angle produced by astrophysical configurations in the weak gravitational regime when a plasma medium is taken into account. For applications, we use these methods to introduce new general formulas for the bending angle of light rays in plasma environments in different astrophysical scenarios, generalizing previously known results. We also present new and useful formulas for the separation angle between the images of two sources when they are lensed by an astrophysical object surrounded by plasma. In particular, for the case of a homogeneous plasma we study these corrections for the case of light rays propagating near astrophysical objects described in the weak gravitational regime by a parametrized-post-Newtonian metric which takes into account the mass of the objects and a possible quadrupole moment. Even when our work concentrates on finite distance corrections to the deflection angle, we also obtain as particular cases of our expressions new formulas which are valid for the more common assumption of infinite distance between receiver, lens and source. We also consider the presence of an inhomogeneous plasma media introducing as particular cases of our general results explicit expressions for particular charge number density profiles.Fil: Crisnejo, Gabriel Sebastian. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gallo, Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Rogers, Adam. Brandon University; Canad

International systematic review of utility values associated with cardiovascular disease and reflections on selecting evidence for a UK decision-analytic model

Purpose: Evaluating interventions for cardiovascular disease (CVD) requires estimates of its effect on utility. We aimed to (1) systematically review utility estimates for CVDs published since 2013, (2) critically appraise UK-relevant estimates and calculate corresponding baseline utility multipliers. Methods: We searched MEDLINE and Embase (22/04/2021) using CVD and utility terms. We screened results for primary studies reporting utility distributions for people with experience of heart failure, myocardial infarction, peripheral arterial disease, stable angina, stroke, transient ischemic attack or unstable angina. We extracted characteristics from studies included. For UK estimates based on the EuroQoL five dimension (EQ-5D) measure, we assessed risk of bias and applicability to a decision-analytic model, pooled arms/time-points as appropriate, and estimated baseline utility multipliers using predicted utility for age- and sex- matched populations without CVD. We sought utility sources from directly applicable studies with low risk of bias, prioritising plausibility of severity ordering in our base case model and highest population ascertainment in a sensitivity analysis. Results: Most of the 403 studies identified used EQ-5D (n=217) and most assessed OECD populations (n=262), although measures and countries varied widely. UK studies using EQ-5D (n=29) produced very heterogeneous baseline utility multipliers for each type of CVD, precluding meta-analysis and implying different possible severity orderings. We could find sources which provided a plausible ordering of utilities whilst adequately representing health-states. Conclusions: We catalogued international CVD utility estimates and calculated UK-relevant baseline utility multipliers. Modellers should consider unreported sources of heterogeneity, such as population differences, when selecting utility evidence from reviews.Highlights• Published systematic reviews have summarised estimates of utility associated with cardiovascular disease published up to 2013.• We (1) reviewed utility estimates for seven types of cardiovascular disease published since 2013, (2) critically appraised UK-relevant studies and (3) estimated the effect of each cardiovascular disease on baseline utility.• Our review (1) recommends a consistent and reliable set of baseline utility multipliers for seven types of cardiovascular disease and (2) provides systematically identified reference information for researchers seeking utility evidence for their own context.<br/

The Applicability of Pulsed Plasma Thrusters to Rendezvous and Docking of Cubesats

Despite the interest in formation flying and cubesats over something like the last decade or so, close controlled formation flying of two cubesat size spacecraft has not been achieved. Similarly, despite the growing interest in propulsion systems for cubesats, there are very few commercially available and flight ready systems. If these are coupled with the realization that formation flying could be an enabling technology for cubesats [1] enhancing capabilities and opening up possibilities for new types of missions, it seemed timely to revisit the problem of rendezvous and docking for cubesats to examine what might be possible with a pulsed propulsion system based on a pulsed plasma thruster(PPT) that is close to flight qualification The approach taken was to build on previous wor

RekomGNN: Visualizing, Contextualizing and Evaluating Graph Neural Networks Recommendations

Content recommendation tasks increasingly use Graph Neural Networks, but it remains challenging for machine learning experts to assess the quality of their outputs. Visualization systems for GNNs that could support this interrogation are few. Moreover, those that do exist focus primarily on exposing GNN architectures for tuning and prediction tasks and do not address the challenges of recommendation tasks. We developed RekomGNN, a visual analytics system that supports ML experts in exploring GNN recommendations across several dimensions and making annotations about their quality. RekomGNN straddles the design space between Neural Network and recommender system visualization to arrive at a set of encoding and interaction choices for recommendation tasks. We found that RekomGNN helps experts make qualitative assessments of the GNN's results, which they can use for model refinement. Overall, our contributions and findings add to the growing understanding of visualizing GNNs for increasingly complex tasks

Moore’s Notes on Wittgenstein’s Lectures, Cambridge 1930-1933: Text, Context, and Content

Wittgenstein’s writings and lectures during the first half of the 1930s play a crucial role in any interpretation of the relationship between the Tractatus and the Philosophical Investigations. G. E. Moore’s notes of Wittgenstein’s Cambridge lectures, 1930-1933, offer us a remarkably careful and conscientious record of what Wittgenstein said at the time, and are much more detailed and reliable than previously published notes from those lectures. The co-authors are currently editing these notes of Wittgenstein’s lectures for a book to be published by Cambridge University Press. We describe the materials that make up Moore’s notes, explain their unique value, review the principal editorial challenges that these materials present, and provide a brief outline of our editorial project

Shark-diving tourism as a financing mechanism for shark conservation strategies in Malaysia

This study estimated the economic value of the shark-diving industry in Semporna, the most popular diving destination of Malaysia, by surveying the expenditures of diving tourists and dive operators through the region. A willingness-to-pay survey was also used to estimate the potential of the industry as a financing mechanism for enforcement and management of a hypothetical Marine Protected Area (MPA) to conserve shark populations. The study showed that in 2012, shark-diving tourism provided direct revenues in excess of USD 9.8 million to the Semporna region. These economic benefits had a flow-on effect, generating more than USD 2 million in direct taxes to the government and USD 1.4 million in salaries to the community. A contingent valuation analysis indicated that implementation of a fee paid by divers could generate over USD 2 million for management and enforcement of the MPA each year. These findings suggest that shark diving is an important contributor to the economy of the Semporna region that could be used as a mechanism to assist financial resourcing for management and conservation strategies

Determining epigenetic memory in kidney proximal tubule cell derived induced pluripotent stem cells using a quadruple transgenic reprogrammable mouse

The majority of nucleated somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs). The process of reprogramming involves epigenetic remodelling to turn on pluripotency-associated genes and turn off lineage-specific genes. Some evidence shows that iPSCs retain epigenetic marks of their cell of origin and this epigenetic memory influences their differentiation potential, with a preference towards their cell of origin. Here, we reprogrammed proximal tubule cells (PTC) and tail tip fibroblasts (TTF), from a reprogrammable mouse to iPSCs and differentiated the iPSCs to renal progenitors to understand if epigenetic memory plays a role in renal differentiation. This model allowed us to eliminate experimental variability due to donor genetic differences and transfection of the reprogramming factors such as copy number and integration site. In this study we demonstrated that early passage PTC iPSCs and TTF iPSCs expressed low levels of renal progenitor genes and high levels of pluripotency-associated genes, and the transcriptional levels of these genes were not significantly different between PTC iPSCs and TTF iPSCs. We used ChIP-seq of H3K4me3, H3K27me3, H3K36me3 and global DNA methylation profiles of PTC iPSCs and TTF iPSCs to demonstrate that global epigenetic marks were not different between the cells from the two different sets of tissue samples. There were also no epigenetic differences observed when kidney developmental genes and pluripotency-associated genes were closely examined. We did observe that during differentiation to renal progenitor cells the PTC iPSC-derived renal cells expressed higher levels of three renal progenitor genes compared to progenitors derived from TTF iPSCs but the underlying DNA methylation and histone methylation patterns did not suggest an epigenetic memory basis for this

Demonstrating the Principles of Aperture Synthesis with the Very Small Radio Telescope

We have developed a set of college-level, table-top labs for teaching the basics of radio interferometry and aperture synthesis. These labs are performed with the Very Small Radio Telescope (VSRT), an interferometer using satellite TV electronics as detectors and compact fluorescent light bulbs as microwave signal sources. The hands-on experience provided by the VSRT in these labs allows students to gain a conceptual understanding of radio interferometry and aperture synthesis without the rigorous mathematical background traditionally required