Verbena brasiliensis Vell.

https://thekeep.eiu.edu/herbarium_specimens_byname/19329/thumbnail.jp

Verbena brasiliensis Vell.

https://thekeep.eiu.edu/herbarium_specimens_byname/19329/thumbnail.jp

Verbena halei Small

https://thekeep.eiu.edu/herbarium_specimens_byname/19319/thumbnail.jp

Verbena halei Small

https://thekeep.eiu.edu/herbarium_specimens_byname/19319/thumbnail.jp

Verbena tenuisecta Briq.

https://thekeep.eiu.edu/herbarium_specimens_byname/19379/thumbnail.jp

Interactions of a String Inspired Graviton Field

We continue to explore the possibility that the graviton in two dimensions is related to a quadratic differential that appears in the anomalous contribution of the gravitational effective action for chiral fermions. A higher dimensional analogue of this field might exist as well. We improve the defining action for this diffeomorphism tensor field and establish a principle for how it interacts with other fields and with point particles in any dimension. All interactions are related to the action of the diffeomorphism group. We discuss possible interpretations of this field.Comment: 12 pages, more readable, references adde

Acer rubrum Wats.

https://thekeep.eiu.edu/herbarium_specimens_byname/21750/thumbnail.jp

Myrica cerifera L.

https://thekeep.eiu.edu/herbarium_specimens_byname/21478/thumbnail.jp

The Impact of Shape on the Perception of Euler Diagrams

Euler diagrams are often used for visualizing data collected into sets. However, there is a significant lack of guidance regarding graphical choices for Euler diagram layout. To address this deficiency, this paper asks the question `does the shape of a closed curve affect a user's comprehension of an Euler diagram?' By empirical study, we establish that curve shape does indeed impact on understandability. Our analysis of performance data indicates that circles perform best, followed by squares, with ellipses and rectangles jointly performing worst. We conclude that, where possible, circles should be used to draw effective Euler diagrams. Further, the ability to discriminate curves from zones and the symmetry of the curve shapes is argued to be important. We utilize perceptual theory to explain these results. As a consequence of this research, improved diagram layout decisions can be made for Euler diagrams whether they are manually or automatically drawn