Probabilistic completeness of RRT for geometric and kinodynamic planning with forward propagation

The Rapidly-exploring Random Tree (RRT) algorithm has been one of the most prevalent and popular motion-planning techniques for two decades now. Surprisingly, in spite of its centrality, there has been an active debate under which conditions RRT is probabilistically complete. We provide two new proofs of probabilistic completeness (PC) of RRT with a reduced set of assumptions. The first one for the purely geometric setting, where we only require that the solution path has a certain clearance from the obstacles. For the kinodynamic case with forward propagation of random controls and duration, we only consider in addition mild Lipschitz-continuity conditions. These proofs fill a gap in the study of RRT itself. They also lay sound foundations for a variety of more recent and alternative sampling-based methods, whose PC property relies on that of RRT

TB156: Woody Landscape Plant Cold-Hardiness Ratings

The Lyle E. Littlefield Ornamentals Trial Garden has served as an excellent choice for testing winter survival of landscape plants. It is located on approximately 5 hectares of land comprising the highest elevation and windiest site on Marsh Island. The site is in USDA hardiness zone 4a. The soil is highly variable, ranging from a fine sandy loam to marine clay, with many stones throughout. In general, most plants are cultivated in beds mulched with mixed soft wood bark from a local mill. Plants receive supplemental irrigation during the first two seasons after planting, and thereafter irrigation is supplied only during periods of severe drought. Pest control is primarily nonchemical in nature. No plants have been given winter protection other than mulch.https://digitalcommons.library.umaine.edu/aes_techbulletin/1056/thumbnail.jp

Bioenergy harvesting impacts on ecologically important stand structure and habitat characteristics

Demand for forest bioenergy fuel is increasing in the northern forest region of eastern North America and beyond, but ecological impacts, particularly on habitat, of bioenergy harvesting remain poorly explored in the peer-reviewed literature. Here, we evaluated the impacts of bioenergy harvests on stand structure, including several characteristics considered important for biodiversity and habitat functions. We collected stand structure data from 35 recent harvests in northern hardwood-conifer forests, pairing harvested areas with unharvested reference areas. Biometrics generated from field data were analyzed using a multi-tiered nonparametric uni-and multivariate statistical approach. In analyses comparing harvested to reference areas, sites that had been whole-tree harvested demonstrated significant differences (relative negative contrasts, P \u3c 0.05) in snag density, large live-tree density, well-decayed downed coarse woody debris volume, and structural diversity index (H) values, while sites that had not been whole-tree harvested did not exhibit significant differences. Classification and regression tree (CART) analyses suggested that the strongest predictors of structural retention, as indicated by downed woody debris volumes and H index, were silvicultural treatment and equipment type rather than the percentage of harvested volume allocated to bioenergy uses. In general, bioenergy harvesting impacts were highly variable across the study sites, suggesting a need for harvesting guidelines aimed at encouraging retention of ecologically important structural attributes. © 2012 by the Ecological Society of America

Aflatoxin B1 in Corn Silage

Nineteen piles and bunk silos of corn silage were sampled in late fall of 1976 and early spring of 1977. These samples were assayed for aflatoxin Bl, a potent mycotoxin, using a newly developed procedure. No aflatoxin Bl (<5 ug/kg) was detected in any of the 270 samples of corn silage

Bisporangiate Inflorescences in Pseudotsuga

Author Institution: New York Conservation Department, Albany, N. Y

Design and Benchmark Testing for Open Architecture Reconfigurable Mobile Spirometer and Exhaled Breath Monitor with GPS and Data Telemetry.

Portable and wearable medical instruments are poised to play an increasingly important role in health monitoring. Mobile spirometers are available commercially, and are used to monitor patients with advanced lung disease. However, these commercial monitors have a fixed product architecture determined by the manufacturer, and researchers cannot easily experiment with new configurations or add additional novel sensors over time. Spirometry combined with exhaled breath metabolite monitoring has the potential to transform healthcare and improve clinical management strategies. This research provides an updated design and benchmark testing for a flexible, portable, open access architecture to measure lung function, using common Arduino/Android microcontroller technologies. To demonstrate the feasibility and the proof-of-concept of this easily-adaptable platform technology, we had 43 subjects (healthy, and those with lung diseases) perform three spirometry maneuvers using our reconfigurable device and an office-based commercial spirometer. We found that our system compared favorably with the traditional spirometer, with high accuracy and agreement for forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), and gas measurements were feasible. This provides an adaptable/reconfigurable open access "personalized medicine" platform for researchers and patients, and new chemical sensors and other modular instrumentation can extend the flexibility of the device in the future