An Evolutionary Game Theoretic Model of Rhino Horn Devaluation

Rhino populations are at a critical level due to the demand for rhino horn and the subsequent poaching. Wildlife managers attempt to secure rhinos with approaches to devalue the horn, the most common of which is dehorning. Game theory has been used to examine the interaction of poachers and wildlife managers where a manager can either `dehorn' their rhinos or leave the horn attached and poachers may behave `selectively' or `indiscriminately'. The approach described in this paper builds on this previous work and investigates the interactions between the poachers. We build an evolutionary game theoretic model and determine which strategy is preferred by a poacher in various different populations of poachers. The purpose of this work is to discover whether conditions which encourage the poachers to behave selectively exist, that is, they only kill those rhinos with full horns. The analytical results show that full devaluation of all rhinos will likely lead to indiscriminate poaching. In turn it shows that devaluing of rhinos can only be effective when implemented along with a strong disincentive framework. This paper aims to contribute to the necessary research required for informed discussion about the lively debate on legalising rhino horn trade

Moving beyond simple descriptive statistics in the analysis of online wildlife trade: an example from clustering and ordination

Collecting data for reports on online wildlife trade is resource-intensive and time-consuming. Learning often focuses on the main item traded by each country only. However, online trade is increasing, providing potential to update the conversation from a national scale to a global scale. We demonstrate how hierarchical clustering can identify wildlife items that follow similar trading patterns. We also ordinate the clusters, and seek correlations between the clusters and global measures, such as Worldwide Governance Indicators. We primarily use a sample dataset from a published report of online traded wildlife, covering 16 countries and 31 taxa or product types. Clustering provided immediate insights, such as rhinos and pangolins were traded similarly to ivory and suspected ivory. Five out of eight clusters represented items predominately traded by one country. An ordination of these clusters, and representation of global measures on the ordination axis, show a strong correlation of the ‘Voice and accountability' score with the clusters. Consequently, from the ‘Voice and accountability' score of the United States, a country not included in our dataset, we inferred that it traded elephant items (not ivory) and owl items during 2014

A genetic algorithm approach for modelling low voltage network demands

Distribution network operators (DNOs) are increasingly concerned about the impact of low carbon technologies on the low voltage (LV) networks. More advanced metering infrastructures provide numerous opportunities for more accurate load flow analysis of the LV networks. However, such data may not be readily available for DNOs and in any case is likely to be expensive. Modelling tools are required which can provide realistic, yet accurate, load profiles as input for a network modelling tool, without needing access to large amounts of monitored customer data. In this paper we outline some simple methods for accurately modelling a large number of unmonitored residential customers at the LV level. We do this by a process we call buddying, which models unmonitored customers by assigning them load profiles from a limited sample of monitored customers who have smart meters. Hence the presented method requires access to only a relatively small amount of domestic customers' data. The method is efficiently optimised using a genetic algorithm to minimise a weighted cost function between matching the substation data and the individual mean daily demands. Hence we can show the effectiveness of substation monitoring in LV network modelling. Using real LV network modelling, we show that our methods perform significantly better than a comparative Monte Carlo approach, and provide a description of the peak demand behaviour

The reception of French painting in Britain, c. 1690–c. 1740

The reception of French pictures, artists and art literature in Britain during the early eighteenth century has hitherto remained an understudied area within British art history. Modern scholarship has often characterised this period as experiencing an influx of continental influences which aided the development of British art, collecting, and patronage. However, there is the tendency to focus such a study within the latter decades of the century. This thesis combines document-based research with pictorial study in order to determine the ways that English audiences responded to the presence of French pictures, but also imitated, modified and criticised French artistic ideas and forms during the period Four chapters explore the different ways in which English travellers, collectors and patrons came to acquire, commission and learn about French painting. This will firstly be achieved through a consideration of English artists visiting Paris during this period, and associated travel literature, particularly the notebook of the painter James Thornhill. This leads to an examination of the interactions between collectors and their agents and dealers in the acquisition of French pictures on the London art market and abroad. This study also establishes the impact of French visual and literary sources on the mural paintings of Louis Laguerre and his English patrons. Lastly, this thesis considers the readership for French art literature and the contribution of English translations and treatises. Together, these topics serve to illustrate the multitude of ways in which French art and ideas became embedded within English artistic culture during this period

Evaluating the effectiveness of storage control in reducing peak demand on low voltage feeders

Uptake of Low Carbon Technologies is likely to lead to increased demand in distribution networks and consequently could impose additional stress on the networks. Battery Energy Storage Systems (BESS) are identified as a feasible alternative to traditional network reinforcement. This paper analyses two BESS scheduling algorithms (Model Predictive Control (MPC) and fixed schedule) supplied with forecasts from five methods for predicting demand on 100 low voltage feeders. Results show that forecasting feeders with higher mean daily demand produces lower mean absolute errors and better peak demand reduction. MPC with simple error improves peak reduction over fixed schedule for feeders with lower mean daily demand

Identifying key factors of the transmission dynamics of drug-resistant malaria

Development of resistance to malaria treatments remains a great threat to continued malaria burden reduction and elimination. Quantifying the impact of key factors which increase the emergence and spread of drug resistance can guide intervention strategies. Whilst modelling provides a framework to understand these factors, we show that a simple of model with a sensitive-resistant dichotomy leads to incorrectly focusing on reducing the treatment rate as a means to prevent resistance. Instead we present a model that considers the development of resistance within hosts as a scale, and we then quantify the number of resistant infections that would arise from a single sensitive infection. By including just one step before full resistance, the model highlights that disrupting this development is more effective than reducing treatment rate. This result is compounded when the model includes the more realistic scenario of several intermediary steps. An additional comparison to transmission probabilities, where resistant infections are less likely to be transmitted (cost of resistance), confirms that preventing the establishment of resistance is more effective than controlling the spread. Our work strongly advocates for further studies into within-host models of resistance, including the potential of combination therapies to disrupt emergence

Devaluing rhino horns as a theoretical game

The poaching of rhinos has increased dramatically in recent years, creating an ongoing problem and cost to rhino managers. A manager may decrease the reward to the poacher by devaluing the horn such as dehorning so that only a stub is left, or inserting a poison, dye or GPS tracker. However, as it is impossible to remove all value of the horn (a stub remains, poison fades, or GPS trackers can be removed) a poacher may still kill the rhino for the partial gain from the horn, and to avoid tracking this particular rhino in the future. We consider the problem as a theoretical game, where the players are poachers and a rhino manager. By considering the payoff to both manger and poachers we highlight the manager's struggle to discourage poachers to not kill a devalued rhino, despite the loss of time, and increase of risk, to the poacher. Generally, the manager can only influence the situation if virtually all rhino horns are devalued, or the risk involved to the poacher is increased, such as through greater enforcement. However, the cost to devalue the last few rhinos may be very costly due to the sparsity of rhinos, and the rhino manager can easily make a loss by trying to devalue the last, few rhinos. But, whilst a few rhinos remain with their intact horn, a poacher is unlikely to avoid a particular ranch

Glaucoma Home Monitoring Using a Tablet- Based Visual Field Test (Eyecatcher): An Assessment of Accuracy and Adherence Over 6 Months

PURPOSE: To assess accuracy and adherence of visual field (VF) home monitoring in a pilot sample of patients with glaucoma. DESIGN: Prospective longitudinal feasibility and reliability study. METHODS: Twenty adults (median 71 years) with an established diagnosis of glaucoma were issued a tablet perimeter (Eyecatcher) and were asked to perform 1 VF home assessment per eye, per month, for 6 months (12 tests total). Before and after home monitoring, 2 VF assessments were performed in clinic using standard automated perimetry (4 tests total, per eye). RESULTS: All 20 participants could perform monthly home monitoring, though 1 participant stopped after 4 months (adherence: 98% of tests). There was good concordance between VFs measured at home and in the clinic (r = 0.94, P < .001). In 21 of 236 tests (9%), mean deviation deviated by more than ±3 dB from the median. Many of these anomalous tests could be identified by applying machine learning techniques to recordings from the tablets' front-facing camera (area under the receiver operating characteristic curve = 0.78). Adding home-monitoring data to 2 standard automated perimetry tests made 6 months apart reduced measurement error (between-test measurement variability) in 97% of eyes, with mean absolute error more than halving in 90% of eyes. Median test duration was 4.5 minutes (quartiles: 3.9-5.2 minutes). Substantial variations in ambient illumination had no observable effect on VF measurements (r = 0.07, P = .320). CONCLUSIONS: Home monitoring of VFs is viable for some patients and may provide clinically useful data

Acceptability of a home-based visual field test (Eyecatcher) for glaucoma home monitoring: a qualitative study of patients' views and experiences

Objectives To explore the acceptability of home visual field (VF) testing using Eyecatcher among people with glaucoma participating in a 6-month home monitoring pilot study. Design Qualitative study using face-to-face semistructured interviews. Transcripts were analysed using thematic analysis. Setting Participants were recruited in the UK through an advertisement in the International Glaucoma Association (now Glaucoma UK) newsletter. Participants Twenty adults (10 women; median age: 71 years) with a diagnosis of glaucoma were recruited (including open angle and normal tension glaucoma; mean deviation=2.5 to -29.9 dB). Results All participants could successfully perform VF testing at home. Interview data were coded into four overarching themes regarding experiences of undertaking VF home monitoring and attitudes towards its wider implementation in healthcare: (1) comparisons between Eyecatcher and Humphrey Field Analyser (HFA); (2) capability using Eyecatcher; (3) practicalities for effective wider scale implementation; (4) motivations for home monitoring. Conclusions Participants identified a broad range of benefits to VF home monitoring and discussed areas for service improvement. Eyecatcher was compared positively with conventional VF testing using HFA. Home monitoring may be acceptable to at least a subset of people with glaucoma

c-Fms-Mediated Differentiation and Priming of Monocyte Lineage Cells Play a Central Role in Autoimmune Arthritis

Introduction: Tyrosine kinases are key mediators of multiple signaling pathways implicated in rheumatoid arthritis (RA). We previously demonstrated that imatinib mesylate--a Food and Drug Administration (FDA)-approved, antineoplastic drug that potently inhibits the tyrosine kinases Abl, c-Kit, platelet-derived growth factor receptor (PDGFR), and c-Fms--ameliorates murine autoimmune arthritis. However, which of the imatinib-targeted kinases is the principal culprit in disease pathogenesis remains unknown. Here we examine the role of c-Fms in autoimmune arthritis. Methods: We tested the therapeutic efficacy of orally administered imatinib or GW2580, a small molecule that specifically inhibits c-Fms, in three mouse models of RA: collagen-induced arthritis (CIA), anti-collagen antibody-induced arthritis (CAIA), and K/BxN serum transfer-induced arthritis (K/BxN). Efficacy was evaluated by visual scoring of arthritis severity, paw thickness measurements, and histological analysis. We assessed the in vivo effects of imatinib and GW2580 on macrophage infiltration of synovial joints in CIA, and their in vitro effects on macrophage and osteoclast differentiation, and on osteoclast-mediated bone resorption. Further, we determined the effects of imatinib and GW2580 on the ability of macrophage colony-stimulating factor (M-CSF; the ligand for c-Fms) to prime bone marrow-derived macrophages to produce tumor necrosis factor (TNF) upon subsequent Fc receptor ligation. Finally, we measured M-CSF levels in synovial fluid from patients with RA, osteoarthritis (OA), or psoriatic arthritis (PsA), and levels of total and phosphorylated c-Fms in synovial tissue from patients with RA. Results: GW2580 was as efficacious as imatinib in reducing arthritis severity in CIA, CAIA, and K/BxN models of RA. Specific inhibition of c-Fms abrogated (i) infiltration of macrophages into synovial joints of arthritic mice; (ii) differentiation of monocytes into macrophages and osteoclasts; (iii) osteoclast-mediated bone resorption; and (iv) priming of macrophages to produce TNF upon Fc receptor stimulation, an important trigger of synovitis in RA. Expression and activation of c-Fms in RA synovium were high, and levels of M-CSF were higher in RA synovial fluid than in OA or PsA synovial fluid. Conclusions: These results suggest that c-Fms plays a central role in the pathogenesis of RA by mediating the differentiation and priming of monocyte lineage cells. Therapeutic targeting of c-Fms could provide benefit in RA