Let T be an n-node tree of maximum degree 4, and let P be a set of n points in the plane with no two points on the same horizontal or vertical line. It is an open question whether T always has a planar drawing on P such that each edge is drawn as an orthogonal path with one bend (an “L-shaped” edge). By giving new methods for drawing trees, we improve the bounds on the size of the point set P f...

The population-level dynamics of maternally transmitted endosymbionts, including reproductive parasites, depends primarily on the fitness effects and transmission fidelity of these infections. Although experimental laboratory studies have shown that within-host endosymbiont density can affect both of these factors, the existence of such effects in natural populations has not yet been documented...

Danio aesculapii, new species, is described from small rivers on the western slope of the Rakhine Yoma in south-western Myanmar. It is superficially similar to D. choprae from northern Myanmar in having a series of vertical bars anteriorly on the side, but differs from it and other species of Danio in having six instead of seven or more branched dorsal-fin rays, and from all other species of Da...

It is shown that every orthogonal terrain, i.e., an orthogonal (rightangled) polyhedron based on a rectangle that meets every vertical line in a segment, has a grid unfolding: its surface may be unfolded to a single non-overlapping piece by cutting along grid edges defined by coordinate planes through every vertex.

We initiate the study of general neighborhood growth dynamics on two-dimensional Hamming graphs. The decision to add a point is made by counting the currently occupied points on the horizontal and the vertical line through it, and checking whether the pair of counts lies outside a fixed Young diagram. We focus on two related extremal quantities. The first is the size of the smallest set that ev...

BACKGROUND Payers are increasingly holding hospitals accountable for patients' experiences with their care. This may conflict with another trend among US hospitals-greater hospitalist care-as hospitalists may have less familiarity with the history and preferences of their patients compared with primary-care physicians. OBJECTIVE Our objective was to better understand the relationship between ...

From the Department of Neurosciences, University of California, San Diego, La Jolla, California 92093, and the Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston, Texas 77550. Dr. Krausz's present address is the Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston, Texas 77550, and Dr. Friesen's is the Department of Biology',...

One-dimensional patterns subjected to counter-propagative flows or speed jumps exhibit a rich and complex spatiotemporal dynamics, which is characterized by the perpetual emergence of spatiotemporal dislocation chains. Using a universal amplitude equation of drifting patterns, we show that this behavior is a result of a combination of a phase instability and an advection process caused by an in...

We propose here algorithms to perform two new operations on an arrangement of line segments in the plane, represented by a trapezoidal map: the split of the map along a given vertical line D, and the union of two trapezoidal maps computed in two vertical slabs of the plane that are adjacent through a vertical line D. The data structure is a modiied Innuence graph, still allowing dynamic inserti...