ABSTRACT
The spotted lanternfly, Lycorma delicatula (White), is a new invasive pest in the United States. To quantify spotted lanternfly population abundance, one must understand this pest's dispersion pattern, that is, the spatial arrangement of individuals within a population. Spotted lanternflies overwinter in egg masses from late fall to May, making this life stage suitable for population assessments. We measured the dispersion pattern of egg masses at two types of sites: a suburban housing development, where we used individual trees as the sampling unit, and rural woodlots, where we used individual trees and also plots with 5.64 m radius as sampling units. Plots were the same size as those recommended for monitoring the gypsy moth, a well-studied pest with similar egg laying habit to the spotted lanternfly. Egg masses in both sampling units were counted up to a height of 3 m. With trees as the sampling unit, egg masses were aggregated in 12 of 20 rural sampling universes, randomly dispersed at 6, and completely absent at 2. Similar patterns were seen when using the 5.64-m radius rural sampling units and for suburban sampling universes. We calculated sample size requirements for a range of mean densities at a precision of 25 and 30%. Additionally, the vertical distribution of egg masses was characterized on the invasive tree of heaven [Ailanthus altissima (Mill.) Swingle], a preferred host for spotted lanternflies. For small trees, there was a positive relationship between number of egg masses in the bottom 3 m of the tree and the total count.
Subject(s)
Ailanthus , Hemiptera , Animals , Oviposition , Sample Size , TreesABSTRACT
Ten patients with scaphoid non-unions which had been present for longer than 2 years were treated using a vascularised bone graft harvested from the thumb and pedicled on the first dorsal metacarpal artery. Bone harvesting and grafting were performed by a single palmar approach. Concomitant cancellous bone graft was not used. Bone healing was confirmed by CT scans in nine of the ten patients. Persistence of the non-union was observed in one patient who was the oldest in this series, had the longest standing non-union and was a heavy smoker. Twelve months after surgery, nine of the ten patients had significant pain relief with an improved range of motion and grip strength.
Subject(s)
Fractures, Ununited/surgery , Metacarpal Bones/blood supply , Metacarpal Bones/transplantation , Scaphoid Bone/surgery , Thumb/surgery , Adult , Bone Transplantation/methods , Cohort Studies , Fracture Healing , Fractures, Ununited/diagnostic imaging , Hand Strength , Humans , Male , Middle Aged , Pain Measurement , Radiography , Range of Motion, Articular , Scaphoid Bone/diagnostic imaging , Scaphoid Bone/injuries , Thumb/blood supplyABSTRACT
The emergence of chaotic motion is discussed for hard-point like and soft collisions between two particles in a one-dimensional box. It is known that ergodicity may be obtained in hard-point like collisions for specific mass ratios gamma=m(2)/m(1) of the two particles and that Lyapunov exponents are zero. However, if a Yukawa interaction between the particles is introduced, we show analytically that positive Lyapunov exponents are generated due to double collisions close to the walls. While the largest finite-time Lyapunov exponent changes smoothly with gamma , the number of occurrences of the most probable one, extracted from the distribution of finite-time Lyapunov exponents over initial conditions, reveals details about the phase-space dynamics. In particular, the influence of the integrable and pseudointegrable dynamics without Yukawa interaction for specific mass ratios can be clearly identified and demonstrates the sensitivity of the finite-time Lyapunov exponents as a phase-space probe. Being not restricted to two-dimensional problems such as Poincaré sections, the number of occurrences of the most probable Lyapunov exponents suggests itself as a suitable tool to characterize phase-space dynamics in higher dimensions. This is shown for the problem of two interacting particles in a circular billiard.