Measurement of an Elongation of the Pion Source in Z Decays

We measure Bose-Einstein correlations between like-sign charged pion pairs in hadronic Z decays with the L3 detector at LEP. The analysis is performed in three dimensions in the longitudinal center-of-mass system. The pion source is found to be elongated along the thrust axis with a ratio of transverse to longitudinal radius of $0.81\pm 0.02 ^{+0.03}_{-0.19}$

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Fire effects in the coastal lowlands: Hawai'i Volcanoes National Park

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.Since 1975 fire frequency has increased sharply in the coastal lowlands of Hawai'i Volcanoes National Park. This was due largely to increases in grass biomass following the removal of feral goats and/or the spread of fire-tolerant species. Fire effects were studied in 13 sites within five lava or lightning caused burns occurring between 1985 and 1989. The study sites were located in five major plant communities and two ecotones. Grasslands characterized the vegetation of the central coastal lowland sites, and lowland scrub with native shrub overstory and alien grass understory characterized the sites in the eastern lowlands. All of the coastal lowlands were severely impacted by Polynesian cultivation and burning practices, nineteenth century cattle grazing, and 150 years of feral goat browsing and grazing. Cover was determined by point-intercept methods along unreplicated transects established prior to the fire or by replicated burned and unburned pairs of transects. Density of shrubs was determined in plots along the paired transects. Frequency of resprouting of woody plants was determined by monitoring individual plants for one year. The results differed from those observed by Hughes et al. (1991) and Smith and Parman (1981) in the lower submontane seasonal zone. Alien grass cover did not increase in most sites, and total native cover usually increased or remained the same. In the eastern coastal lowlands, fire characteristically stimulated the spread of the native subshrub Waltheria indica, bunchgrass Heteropogon contortus, and shrubs Dodonaea viscosa and Osteomeles anthyllidifolia. Fire however depleted the tall native shrub component by nearly eliminating Wikstroemia sandwicensis. Waltheria and Heteropogon generally were also stimulated in the central lowlands but not sufficiently to increase total native plant cover in most sites. These findings lead to the conclusions that the Park's policy of total fire suppression should continue to protect the native shrub component of the rare Wikstroemia shrubland, allow natural recolonization of the central grasslands by native trees and shrubs, and prevent the spread of the disruptive fire-stimulated Melinis and Hyparrhenia. However, a judicious use of prescribed burning, on an experimental basis, may be useful in establishing fuel breaks and stimulating the recovery of native species such as Heteropogon and Dodonaea.National Park Service Cooperative Agreement CA 8007 2 900

Fast Semi-dense Surface Reconstruction from Stereoscopic Video in Laparoscopic Surgery

Liver resection is the main curative option for liver metastases. While this offers a 5-year survival rate of 50%, only about 20% of all patients are suitable for laparoscopic resection and thus being able to take advantage of minimally invasive surgery. One underlying difficulty is the establishment of a safe resection margin while avoiding critical structures. Intra-operative registration of patient scan data may provide a solution. However, this relies on fast and accurate reconstruction methods to obtain the current shape of the liver. Therefore, this paper presents a method for high-resolution stereoscopic surface reconstruction at interactive rates. To this end, a feature-matching propagation method is adapted to multi-resolution processing to enable parallelisation, remove global synchronisation issues and hence become amenable to a GPU-based implementation. Experiments are conducted on a planar target for reconstruction noise estimation and a visually realistic silicone liver phantom. Results highlight an average reconstruction error of 0.6 mm on the planar target, 2.4-5.7 mm on the phantom and processing times averaging around 370 milliseconds for input images of size 1920 x 540