TY - JOUR AB - The dispersal rate of the grasshopper Podisma pedestris has been measured, with the aim of interpreting the width of a chromosomal cline. 171 adults were marked individually, and released within the cline. 169 movements were seen over three subsequent scorings; the distribution of distances, after correction for the loss of long distance dispersants, was close to a normal curve, but there was an initial shift of ten metres, perhaps towards a better habitat. The linear variance increased at about 214 m2 day- 1, which corresponds to a standard deviation of 207 m gen- 1/2 over a 20 day life span. Statistical uncertainty in this estimate can be expressed using a distribution-free maximum likelihood method, which gives support limits of 186- 270 m gen- 1/2. However, the main errors come from extrapolating from this experiment to the cline as a whole. AU - Barton, Nicholas H AU - Hewitt, Godfrey ID - 3669 IS - 2 JF - Heredity SN - 0018-067X TI - A measurement of dispersal in the grasshopper Podisma pedestris (Orthoptera: Acrididae) VL - 48 ER - TY - JOUR AB - An algorithm for the geometric problem of determining a line (called a stabbing line) which intersects each ofn given line segments in the plane is presented. As a matter of fact, the algorithm computes a description of all stabbing lines. A purely geometric fact is proved which infers that this description requiresO(n) space to be specified. Our algorithm computes it inO(n logn) time which is optimal in the worst case. Using the description of the stabbing lines, we are able to decide inO(logn) time whether or not a specified line is a stabbing line. Finally, the problem of maintaining the description of all stabbing lines while inserting and deleting line segments is addressed. AU - Edelsbrunner, Herbert AU - Maurer, Hermann AU - Preparata, Franco AU - Rosenberg, Arnold AU - Welzl, Emo AU - Wood, Derick ID - 4129 IS - 3 JF - BIT Numerical Mathematics SN - 0006-3835 TI - Stabbing line segments VL - 22 ER - TY - JOUR AU - Edelsbrunner, Herbert AU - Overmars, Mark ID - 4131 IS - 3 JF - Information Processing Letters TI - On the equivalence of some rectangle problems VL - 14 ER - TY - JOUR AU - Edelsbrunner, Herbert AU - Maurer, Hermann AU - Kirkpatrick, David ID - 4130 IS - 2 JF - Information Processing Letters SN - 0020-0190 TI - Polygonal intersection searching VL - 14 ER - TY - JOUR AU - Barton, Nicholas H ID - 4331 IS - 4 JF - Evolution SN - 0014-3820 TI - The structure of the hybrid zone in Uroderma bilobatum (Chiroptera: Phyllostomatidae) VL - 36 ER -