RATLER: Robotic All-Terrain Lunar Exploration Rover

A robotic rover vehicle designed for use in the exploration of the Lunar surface is described. The Robotic All-Terrain Lunar Exploration Rover (RATLER) is a four wheeled all-wheel-drive dual-body vehicle. A uniquely simple method of chassis articulation is employed which allows all four wheels to remain in contact with the ground, even while climbing over step-like obstacles as large as 1.3 wheel diameters. Skid steering and modular construction are used to produce a simple, rugged, highly agile mobility chassis with a reduction in the number of parts required when compared to current designs being considered for planetary exploration missions. The design configuration, mobility parameters, and performance of several existing RATLER prototypes are discussed

Architectures & requirements for advanced weapon controllers.

This report describes work done in FY2003 under Advanced and Exploratory Studies funding for Advanced Weapons Controllers. The contemporary requirements and envisioned missions for nuclear weapons are changing from the class of missions originally envisioned during development of the current stockpile. Technology available today in electronics, computing, and software provides capabilities not practical or even possible 20 years ago. This exploratory work looks at how Weapon Electrical Systems can be improved to accommodate new missions and new technologies while maintaining or improving existing standards in nuclear safety and reliability

Studies on Lake Erie's littoral algae; Host specificity and temporal periodicity of epiphytic diatoms

Substratum specificity and temporal periodicity of the attached diatom flora upon three aquatic vascular plants and an artificial substratum were examined in three Lake Erie marshes. No qualitative or quantitative specificity for substrata was observed. Variability of diatom assemblage structure within replicate samples of a particular substratum type was as great as, or greater than, variability between substrata. Diatom assemblages upon dowel rod displayed a mid to late summer density maximum. Variability of density maxima upon natural substrata was attributed to different growth rates of the host macrophytes. Diatom assemblages within each sampling site possessed a distinct temporal periodicity indicating that factors affecting diatom growth are heterogeneous in distribution throughout Lake Erie's littoral zone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42923/1/10750_2004_Article_BF00013712.pd

Insights into APC/C: from cellular function to diseases and therapeutics

Anaphase-promoting complex/cyclosome (APC/C) is a multifunctional ubiquitin-protein ligase that targets different substrates for ubiquitylation and therefore regulates a variety of cellular processes such as cell division, differentiation, genome stability, energy metabolism, cell death, autophagy as well as carcinogenesis. Activity of APC/C is principally governed by two WD-40 domain proteins, Cdc20 and Cdh1, in and beyond cell cycle. In the past decade, the results based on numerous biochemical, 3D structural, mouse genetic and small molecule inhibitor studies have largely attracted our attention into the emerging role of APC/C and its regulation in biological function, human diseases and potential therapeutics. This review will aim to summarize some recently reported insights into APC/C in regulating cellular function, connection of its dysfunction with human diseases and its implication of therapeutics

Typisierung von Clostridium difficile mit Bakteriozinen

Available from: Zentralstelle fuer Agrardokumentation und -information (ZADI), Villichgasse 17, D-53177 Bonn / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Control of Multiple Robotic Sentry Vehicles

As part of a project for the Defense Advanced Research Projects Agency, Sandia National Laboratories is developing and testing the feasibility of using of a cooperative team of robotic sentry vehicles to guard a perimeter and to perform surround and diversion tasks. This paper describes on-going activities in the development of these robotic sentry vehicles. To date, we have developed a robotic perimeter detection system which consists of eight ''Roving All Terrain Lunar Explorer Rover'' (RATLER{trademark}) vehicles, a laptop-based base-station, and several Miniature Intrusion Detection Sensors (MIDS). A radio frequency receiver on each of the RATLER vehicles alerts the sentry vehicles of alarms from the hidden MIDS. When an alarm is received, each vehicle decides whether it should investigate the alarm based on the proximity of itself and the other vehicles to the alarm. As one vehicle attends an alarm, the other vehicles adjust their position around the perimeter to better prepare for another alarm. We have also demonstrated the ability to drive multiple vehicles in formation via tele-operation or by waypoint GPS navigation. This is currently being extended to include mission planning capabilities. At the base-station, the operator can draw on an aerial map the goal regions to be surrounded and the repulsive regions to be avoided. A potential field path planner automatically generates a path from the vehicles' current position to the goal regions while avoiding the repulsive regions and the other vehicles. This path is previewed to the operator before the regions are downloaded to the vehicles. The same potential field path planner resides on the vehicle, except additional repulsive forces from on-board proximity sensors guide the vehicle away from unplanned obstacles

Cooperative Control of a Squad of Mobile Vehicles

Tasks such as the localization of chemical sources, demining, perimeter control, surveillance and search and rescue missions are usually performed by teams of people. At least conceptually, large groups of relatively cheap mobile vehicles outfitted with sensors should be able to automatically accomplish some of these tasks. Sandia National Labs is currently developing a swarm of semi-autonomous all terrain vehicles for remote cooperative sensing applications. This paper will describe the capabilities of this system and outline some of its possible applications. Cooperative control and sensing strategies will also be described. Eight Roving All Terrain Lunar Explorer Rovers (RATLERs) have been built at Sandia as a test platform for cooperative control and sensing applications. This paper will first describe the hardware capabilities of the RATLER system. Then it will describe the basic control algorithm for GPS based navigation and obstacle avoidance. A higher level cooperative control task will then be described

Freshwater Mussel Assemblages at the Lotic-Lentic Interface Along Lake Erie

Where a stream enters a large lake, the mouth represents a transitional environment that is neither truly lotic nor lentic in nature and therefore is likely to affect the fauna present. Theory on habitat area and stream size predicts that species richness will increase farther downstream as watershed size increases, but as stream gradient and thus flow rate declines, stream mouths present a different and understudied habitat. Freshwater mussels in the family Unionidae are in decline, and therefore understanding how they respond across diverse habitats is also critical. We sampled mussel assemblages from 2010 to 2012 in the lower reaches of twelve small tributaries and two large embayments of the western and central basins of Lake Erie, where watershed size ranged from 10 to 4000 km . These watersheds were assessed for land use by remote sensing and for basic water chemistry and the composition of their benthos by standard protocols. Evidence of native unionid mussels occurred in all watersheds, with 14 species found alive, which make up 75% of mussel species still present throughout Lake Erie. A species-area relationship occurred, although the effect was weaker than that present for flowing streams in the region. Additionally, the habitat and corresponding assemblages were characterized as depositional in nature, which logically follow high agricultural land use and corresponding high levels of turbidity and the proportion of silt and clay. Therefore, the lake environment influenced mussel assemblages, yet these conditions appear to limit dreissenid mussels in river mouths.