Integration of production and financial models to analyse the financial impact of livestock diseases: a case study of Schmallenberg virus disease on British and French dairy farms

AIMS AND OBJECTIVES: The aim of the study was to investigate and compare the financial impact of Schmallenberg disease for different dairy production types in the United Kingdom and France. MATERIALS AND METHODS: Integrated production and financial models for dairy cattle were developed and applied to Schmallenberg virus (SBV) disease in a British and French context. The five main production systems that prevail in these two countries were considered. Their respective gross margins measuring the holding's profitability were calculated based on public benchmarking, literature and expert opinion data. A partial budget analysis was performed within each production model to estimate the impact of SBV in the systems modelled. Two disease scenarios were simulated: low impact and high impact. RESULTS: The model gross margin obtained per cow space and year ranged from £1014 to £1484 for the UK and from £1037 to £1890 for France depending on the production system considered. In the UK, the net SBV disease costs in £/cow space/year for an average dairy farm with 100 milking spaces were estimated between £16.3 and £51.4 in the high-impact scenario and between £8.2 and £25.9 in the low-impact scenario. For France, the net SBV disease costs in £/cow space/year ranged from £19.6 to £48.6 in the high-impact scenario and £9.7 to £22.8 in the low-impact scenario, respectively. CONCLUSION: The study illustrates how the combination of production and financial models allows assessing disease impact taking into account differing management and husbandry practices and associated price structures in the dairy sector. It supports decision-making of farmers and veterinarians who are considering disease control measures as it provides an approach to estimate baseline disease impact in common dairy production systems in the UK and France

Locating the Source of Diffusion in Large-Scale Networks

How can we localize the source of diffusion in a complex network? Due to the tremendous size of many real networks--such as the Internet or the human social graph--it is usually infeasible to observe the state of all nodes in a network. We show that it is fundamentally possible to estimate the location of the source from measurements collected by sparsely-placed observers. We present a strategy that is optimal for arbitrary trees, achieving maximum probability of correct localization. We describe efficient implementations with complexity O(N^{\alpha}), where \alpha=1 for arbitrary trees, and \alpha=3 for arbitrary graphs. In the context of several case studies, we determine how localization accuracy is affected by various system parameters, including the structure of the network, the density of observers, and the number of observed cascades.Comment: To appear in Physical Review Letters. Includes pre-print of main paper, and supplementary materia

Ultrasonic Tracking of Migratory Fishes with an Internal Tag

First paragraph: A small ultrasonic tag, 9 mm by 40 mm in size, has been developed by members of the fish orientation group at the University of Wisconsin. The tag emits a continuous signal at approximately 65 kc/sec. The signal is received via a directional hydrophone and a high quality communications receiver. Tracking ranges of up to 1 km have been obtained. The placement of the tag is internal: either into the stomach or into the body cavity of the fish. The tags and tracking equipment have been successfully employed in studies on the open water movements and orientation of white bass during their spawning migration

Ultrasonic Tracking of Migratory Fishes with an Internal Tag

First paragraph: A small ultrasonic tag, 9 mm by 40 mm in size, has been developed by members of the fish orientation group at the University of Wisconsin. The tag emits a continuous signal at approximately 65 kc/sec. The signal is received via a directional hydrophone and a high quality communications receiver. Tracking ranges of up to 1 km have been obtained. The placement of the tag is internal: either into the stomach or into the body cavity of the fish. The tags and tracking equipment have been successfully employed in studies on the open water movements and orientation of white bass during their spawning migration

A discrete model for studying existence and uniqueness of solutions in nonlinear resistive circuits

AbstractTwo combinatorial problems raised by the fundamental question of the existence and uniqueness of solutions in nonlinear electric circuits are presented. The first problem, namely the existence of a pair of conjugate trees, has been solved in polynomial time using an original model based on matroïd intersection. For the second problem, which is the search of a particular orientation in a multigraph with labeled edges, an elaborate branch and bound procedure is proposed

Ground States in the Spin Boson Model

We prove that the Hamiltonian of the model describing a spin which is linearly coupled to a field of relativistic and massless bosons, also known as the spin-boson model, admits a ground state for small values of the coupling constant lambda. We show that the ground state energy is an analytic function of lambda and that the corresponding ground state can also be chosen to be an analytic function of lambda. No infrared regularization is imposed. Our proof is based on a modified version of the BFS operator theoretic renormalization analysis. Moreover, using a positivity argument we prove that the ground state of the spin-boson model is unique. We show that the expansion coefficients of the ground state and the ground state energy can be calculated using regular analytic perturbation theory

Predicting users' first impressions of website aesthetics with a quantification of perceived visual complexity and colorfulness

Users make lasting judgments about a website's appeal within a split second of seeing it for the first time. This first impression is influential enough to later affect their opinions of a site's usability and trustworthiness. In this paper, we demonstrate a means to predict the initial impression of aesthetics based on perceptual models of a website's colorfulness and visual complexity. In an online study, we collected ratings of colorfulness, visual complexity, and visual appeal of a set of 450 websites from 548 volunteers. Based on these data, we developed computational models that accurately measure the perceived visual complexity and colorfulness of website screenshots. In combination with demographic variables such as a user's education level and age, these models explain approximately half of the variance in the ratings of aesthetic appeal given after viewing a website for 500ms only.Engineering and Applied Science

Evaluation of the Relevance of a Web-Based Ask an Expert Feature: StratSoy and Soy and Human Health Queries

StratSoy, a state-of-the-art Web-based information system, has an Ask an Expert (AE) feature that allows Web site browsers to question experts in 13 areas including Soy and Human Health (SHH). The objectives of this research were to: a) assess the use of the SHH AE feature; b) examine respondent attitudes about soy-related topics to help guide development of a Frequently Asked Questions (FAQ) section; and c) improve the information dissemination process on the Web site based on the results of this research. Study participants were 50 Web site users and 48 people who were unfamiliar with the site. The results of the study indicated topic areas of interest and additional Web site features desired by the respondents. The findings identified specific areas that may be targeted to improve the Web site