Hamiltonian closures for fluid models with four moments by dimensional analysis

Fluid reductions of the Vlasov-Amp{\`e}re equations that preserve the Hamiltonian structure of the parent kinetic model are investigated. Hamiltonian closures using the first four moments of the Vlasov distribution are obtained, and all closures provided by a dimensional analysis procedure for satisfying the Jacobi identity are identified. Two Hamiltonian models emerge, for which the explicit closures are given, along with their Poisson brackets and Casimir invariants

Revisiting Bertin Matrices: New Interactions for Crafting Tabular Visualizations

We present Bertifier, a web app for rapidly creating tabular visualizations from spreadsheets. Bertifier draws from Jacques Bertin's matrix analysis method, whose goal was to “simplify without destroying” by encoding cell values visually and grouping similar rows and columns. Although there were several attempts to bring this method to computers, no implementation exists today that is both exhaustive and accessible to a large audience. Bertifier remains faithful to Bertin's method while leveraging the power of today's interactive computers. Tables are formatted and manipulated through crossets, a new interaction technique for rapidly applying operations on rows and columns. We also introduce visual reordering, a semi-interactive reordering approach that lets users apply and tune automatic reordering algorithms in a WYSIWYG manner. Sessions with eight users from different backgrounds suggest that Bertifier has the potential to bring Bertin's method to a wider audience of both technical and non-technical users, and empower them with data analysis and communication tools that were so far only accessible to a handful of specialists

Dynamic Composite Data Physicalization Using Wheeled Micro-Robots

This paper introduces dynamic composite physicalizations, a new class of physical visualizations that use collections of self-propelled objects to represent data. Dynamic composite physicalizations can be used both to give physical form to well-known interactive visualization techniques, and to explore new visualizations and interaction paradigms. We first propose a design space characterizing composite physicalizations based on previous work in the fields of Information Visualization and Human Computer Interaction. We illustrate dynamic composite physicalizations in two scenarios demonstrating potential benefits for collaboration and decision making, as well as new opportunities for physical interaction. We then describe our implementation using wheeled micro-robots capable of locating themselves and sensing user input, before discussing limitations and opportunities for future work

MyBrush: Brushing and Linking with Personal Agency

We extend the popular brushing and linking technique by incorporating personal agency in the interaction. We map existing research related to brushing and linking into a design space that deconstructs the interaction technique into three components: source (what is being brushed), link (the expression of relationship between source and target), and target (what is revealed as related to the source). Using this design space, we created MyBrush, a unified interface that offers personal agency over brushing and linking by giving people the flexibility to configure the source, link, and target of multiple brushes. The results of three focus groups demonstrate that people with different backgrounds leveraged personal agency in different ways, including performing complex tasks and showing links explicitly. We reflect on these results, paving the way for future research on the role of personal agency in information visualization

Vlasov simulations of kinetic Alfvén waves at proton kinetic scales

Existence of spherical initial data with unit mass, zero energy, and virial less than −1/2 for the relativistic VlasovPoisson equation with attractive coupling J. Math. Phys. 52, 09370

Risk Factors for Diarrhea in Children Under Five Years of Age Residing in Peri-Urban Communities in Cochabamba, Bolivia

This study examined the relationship between childhood diarrhea prevalence and caregiver knowledge of the causes and prevention of diarrhea in a prospective cohort of 952 children \u3c 5 years of age in Cochabamba, Bolivia. The survey of caregiver knowledge found that more than 80% of caregivers were unaware that hand washing with soap could prevent childhood diarrhea. Furthermore, when asked how to keep food safe for children to eat only 17% of caregivers reported hand washing before cooking and feeding a child. Lack of caregiver awareness of the importance of practices related to hygiene and sanitation for diarrhea prevention were significant risk factors for diarrheal disease in this cohort. The knowledge findings from this study suggest that health promotion in these communities should put further emphasis on increasing knowledge of how water treatment, hand washing with soap, proper disposal of child feces, and food preparation relate to childhood diarrhea prevention

Interference and economic damage level of volunteer corn plants in soybeans.

Volunteer corn plants have infested crops sown in succession, causing yield losses. The objective of this study was to evaluate the competitive ability and economic damage level (EDL) of soybean cultivars infested by volunteer corn plants. The experiment was conducted in a randomized block design with one replication. The treatments consisted of six soya cultivars and 12 densities of volunteer corn, hybrid Syngenta 488 Vip 3, established for each cultivar, with a minimum of 0 and a maximum of 130 plants m-2. At 30 days after emergence, the plant density, ground cover, leaf area and dry mass of the aerial part of the volunteer corn plants were quantified. In soybeans, grain yield, control cost, bag price and control efficiency were determined. Dry mass was the variable that best fitted the rectangular hyperbola model. The soybean cultivars Nidera 5909 RG, Syngenta 13561 IPRO and Brasmax Lança IPRO showed greater competitive ability and EDL values of 0.07 to 0.20 plants m-2 in the presence of volunteer corn. The lowest EDL values ranged from 0.02 to 0.12 plants m-2 for the cultivars Dom Mario 5958 RSF IPRO, Nidera 6909 IPRO and Brasmax Lança IPRO, which were the least competitive