Dart cookbook

CERN Document Server

Balbaert, Ivo

2014-01-01

If you are a Dart developer looking to sharpen your skills, and get insight and tips on how to put that knowledge into practice, then this book is for you. You should also have a basic knowledge of HTML, and how web applications with browser clients and servers work, in order to build dynamic Dart applications.

Automated space vehicle control for rendezvous proximity operations

Science.gov (United States)

Lea, Robert N.

1988-01-01

Rendezvous during the unmanned space exploration missions, such as a Mars Rover/Sample Return will require a completely automatic system from liftoff to docking. A conceptual design of an automated rendezvous, proximity operations, and docking system is being implemented and validated at the Johnson Space Center (JSC). The emphasis is on the progress of the development and testing of a prototype system for control of the rendezvous vehicle during proximity operations that is currently being developed at JSC. Fuzzy sets are used to model the human capability of common sense reasoning in decision making tasks and such models are integrated with the expert systems and engineering control system technology to create a system that performs comparably to a manned system.

14 CFR 1214.111 - Rendezvous services.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Rendezvous services. 1214.111 Section 1214....111 Rendezvous services. (a) A rendezvous mission involves the rendezvous of the Space Shuttle orbiter... conditions for both dedicated and shared flight rendezvous services will be negotiated on a case-by-case...

The Rendezvous Monitoring Display Capabilities of the Rendezvous and Proximity Operations Program

Science.gov (United States)

Brazzel, Jack; Spehar, Pete; Clark, Fred; Foster, Chris; Eldridge, Erin

2013-01-01

The Rendezvous and Proximity Operations Program (RPOP) is a laptop computer- based relative navigation tool and piloting aid that was developed during the Space Shuttle program. RPOP displays a graphical representation of the relative motion between the target and chaser vehicles in a rendezvous, proximity operations and capture scenario. After being used in over 60 Shuttle rendezvous missions, some of the RPOP display concepts have become recognized as a minimum standard for cockpit displays for monitoring the rendezvous task. To support International Space Station (ISS) based crews in monitoring incoming visiting vehicles, RPOP has been modified to allow crews to compare the Cygnus visiting vehicle s onboard navigated state to processed range measurements from an ISS-based, crew-operated Hand Held Lidar sensor. This paper will discuss the display concepts of RPOP that have proven useful in performing and monitoring rendezvous and proximity operations.

Test Results for the Automated Rendezvous and Capture System

Science.gov (United States)

Cruzen, Craig; Dabney, Richard; Lomas, James

1999-01-01

The Automated Rendezvous and Capture (AR&C) system was designed and tested at NASA's Marshall Space Flight Center (MSFC) to demonstrate technologies and mission strategies for automated rendezvous and docking of spacecraft in Earth orbit, The system incorporates some of the latest innovations in Global Positioning, System space navigation, laser sensor technologies and automated mission sequencing algorithms. The system's initial design and integration was completed in 1998 and has undergone testing at MSFC. This paper describes the major components of the AR&C system and presents results from the official system tests performed in MSFC's Flight Robotics Laboratory with digital simulations and hardware in the loop tests. The results show that the AR&C system can safely and reliably perform automated rendezvous and docking missions in the absence of system failures with 100 percent success. When system failures are included, the system uses its automated collision avoidance maneuver logic to recover in a safe manner. The primary objective of the AR&C project is to prove that by designing a safe and robust automated system, mission operations cost can be reduced by decreasing the personnel required for mission design, preflight planning and training required for crewed rendezvous and docking missions.

A retractable barb needle for drug darts

Directory of Open Access Journals (Sweden)

G.L. van Rooyen

1973-07-01

Full Text Available The mechanism and action of a new retractable barbneedle for drug darts are described. This dart needle is particularly successful in obviating unnecessary flight reactions andtrauma in darted animals, and facilitates the complete injection of the drug dose before the barb is retracted and the dart is dislogded from the animal. The whole process is completed within a few seconds and the expended dart can usually be retrieved in the immediate vicinity where the animal was darted.

A MITgcm/DART ensemble analysis and prediction system with application to the Gulf of Mexico

KAUST Repository

Hoteit, Ibrahim; Hoar, Timothy J.; Gopalakrishnan, Ganesh; Collins, Nancy S.; Anderson, Jeffrey L.; Cornuelle, Bruce D.; Kö hl, Armin; Heimbach, Patrick

2013-01-01

Research Testbed (DART) assimilation package with the Massachusetts Institute of Technology ocean general circulation model (MITgcm). The MITgcm/DART system supports the assimilation of a wide range of ocean observations and uses an ensemble approach

DART 7.0 User Guide

Energy Technology Data Exchange (ETDEWEB)

Enders, Alexander L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lousteau, Angela L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-06-01

The Desktop Analysis Reporting Tool (DART) is a software package that allows users to easily view and analyze daily files that span long periods. DART gives users the capability to quickly determine the state of health of a radiation portal monitor (RPM), troubleshoot and diagnose problems, and view data in various time frames to perform trend analysis. In short, it converts the data strings written in the daily files into meaningful tables and plots. The standalone version of DART (“soloDART”) utilizes a database engine that is included with the application; no additional installations are necessary. There is also a networked version of DART (“polyDART”) that is designed to maximize the benefit of a centralized data repository while distributing the workload to individual desktop machines. This networked approach requires a more complex database manager Structured Query Language (SQL) Server; however, SQL Server is not currently provided with DART. Regardless of which version is used, DART will import daily files from RPMs, store the relevant data in its database, and it can produce reports for status, trend analysis, and reporting purposes.

Fermilab DART run control

International Nuclear Information System (INIS)

Oleynik, G.; Engelfried, J.; Mengel, L.

1996-01-01

DART is the high speed, Unix based data acquisition system being developed by Fermilab in collaboration with seven High Energy Physics Experiments. This paper describes DART run control, which has been developed over the past year and is a flexible, distributed, extensible system for the control and monitoring of the data acquisition systems. The authors discuss the unique and interesting concepts of the run control and some of the experiences in developing it. They also give a brief update and status of the whole DART system

Fermilab DART run control

International Nuclear Information System (INIS)

Oleynik, G.; Engelfried, J.; Mengel, L.

1995-05-01

DART is the high speed, Unix based data acquisition system being developed by Fermilab in collaboration with seven High Energy Physics Experiments. This paper describes DART run control, which has been developed over the past year and is a flexible, distributed, extensible system for the, control and monitoring of the data acquisition systems. We discuss the unique and interesting concepts of the run control and some of our experiences in developing it. We also give a brief update and status of the whole DART system

AggieSat: Autonomous Rendezvous and Docking Technology Demonstrator, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Current autonomous rendezvous and docking (AR&D) capability in low Earth orbit (LEO) is constrained by sensor and effector mass, power, and accuracy limits. To...

Designing the STS-134 Re-Rendezvous: A Preparation for Future Crewed Rendezvous Missions

Science.gov (United States)

Stuit, Timothy D.

2011-01-01

In preparation to provide the capability for the Orion spacecraft, also known as the Multi-Purpose Crew Vehicle (MPCV), to rendezvous with the International Space Station (ISS) and future spacecraft, a new suite of relative navigation sensors are in development and were tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the Orion relative navigation sensors on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle orbiter at the end of the mission. Unlike the rendezvous and docking at the beginning of the mission, the re-rendezvous profile replicates the newly designed Orion coelliptic approach trajectory, something never before attempted with the shuttle orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this rerendezvous to make the flight test successful. Additionally, all of this work had to be integrated with the normal operations of the ISS and shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and rerendezvous trajectory design that would not only prove the design of the relative navigation sensors for the Orion vehicle, but also would serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

75 FR 44794 - Rendezvous International v.

Science.gov (United States)

2010-07-29

... FEDERAL MARITIME COMMISSION [Docket No. 10-07] Rendezvous International v. Chief Cargo Services, Inc., Kaiser Apparel, Inc., Edco Logistics, Inc., Oriental Logistics, Inc., and Razor Enterprise... Federal Maritime Commission (``Commission'') by Rendezvous International (``Rendezvous''), hereinafter...

Progress on DART code optimization

International Nuclear Information System (INIS)

Taboada, Horacio; Solis, Diego; Rest, Jeffrey

1999-01-01

This work consists about the progress made on the design and development of a new optimized version of DART code (DART-P), a mechanistic computer model for the performance calculation and assessment of aluminum dispersion fuel. It is part of a collaboration agreement between CNEA and ANL in the area of Low Enriched Uranium Advanced Fuels. It is held by the Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy, signed on October 16, 1997 between US DOE and the National Atomic Energy Commission of the Argentine Republic. DART optimization is a biannual program; it is operative since February 8, 1999 and has the following goals: 1. Design and develop a new DART calculation kernel for implementation within a parallel processing architecture. 2. Design and develop new user-friendly I/O routines to be resident on Personal Computer (PC)/WorkStation (WS) platform. 2.1. The new input interface will be designed and developed by means of a Visual interface, able to guide the user in the construction of the problem to be analyzed with the aid of a new database (described in item 3, below). The new I/O interface will include input data check controls in order to avoid corrupted input data. 2.2. The new output interface will be designed and developed by means of graphical tools, able to translate numeric data output into 'on line' graphic information. 3. Design and develop a new irradiated materials database, to be resident on PC/WS platform, so as to facilitate the analysis of the behavior of different fuel and meat compositions with DART-P. Currently, a different version of DART is used for oxide, silicide, and advanced alloy fuels. 4. Develop rigorous general inspection algorithms in order to provide valuable DART-P benchmarks. 5. Design and develop new models, such as superplasticity, elastoplastic feedback, improved models for the calculation of fuel deformation and the evolution of the fuel microstructure for

STS-134 Re-Rendezvous Design History

Science.gov (United States)

Stuit, Timothy D.

2011-01-01

In preparation to provide the capability for the Orion spacecraft to rendezvous with the International Space Station (ISS), a new suite of relative navigation sensors are in development and will be tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the instruments on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle Orbiter at the end of the mission. Unlike the initial rendezvous and docking, the re-rendezvous profile would replicate the newly designed Orion coelliptic approach trajectory, something never before attempted with the Shuttle Orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this re-rendezvous to make the flight test successful. And all of this work had to be integrated with the normal operations of the ISS and Shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and re-rendezvous trajectory design that will prove not only the design of the relative navigation sensors for the Orion vehicle, but also will serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

Vision Based Tracker for Dart-Catching Robot

OpenAIRE

Linderoth, Magnus; Robertsson, Anders; Åström, Karl; Johansson, Rolf

2009-01-01

This paper describes how high-speed computer vision can be used in a motion control application. The specific application investigated is a dart catching robot. Computer vision is used to detect a flying dart and a filtering algorithm predicts its future trajectory. This will give data to a robot controller allowing it to catch the dart. The performance of the implemented components indicates that the dart catching application can be made to work well. Conclusions are also made about what fea...

Validating Dart Model

Directory of Open Access Journals (Sweden)

Mazur Jolanta

2014-12-01

Full Text Available The primary objective of the study was to quantitatively test the DART model, which despite being one of the most popular representations of co-creation concept was so far studied almost solely with qualitative methods. To this end, the researchers developed a multiple measurement scale and employed it in interviewing managers. The statistical evidence for adequacy of the model was obtained through CFA with AMOS software. The findings suggest that the DART model may not be an accurate representation of co-creation practices in companies. From the data analysis it was evident that the building blocks of DART had too much of conceptual overlap to be an effective framework for quantitative analysis. It was also implied that the phenomenon of co-creation is so rich and multifaceted that it may be more adequately captured by a measurement model where co-creation is conceived as a third-level factor with two layers of intermediate latent variables.

History of Space Shuttle Rendezvous

Science.gov (United States)

Goodman, John L.

2011-01-01

This technical history is intended to provide a technical audience with an introduction to the rendezvous and proximity operations history of the Space Shuttle Program. It details the programmatic constraints and technical challenges encountered during shuttle development in the 1970s and over thirty years of shuttle missions. An overview of rendezvous and proximity operations on many shuttle missions is provided, as well as how some shuttle rendezvous and proximity operations systems and flight techniques evolved to meet new programmatic objectives. This revised edition provides additional information on Mercury, Gemini, Apollo, Skylab, and Apollo/Soyuz. Some chapters on the Space Shuttle have been updated and expanded. Four special focus chapters have been added to provide more detailed information on shuttle rendezvous. A chapter on the STS-39 mission of April/May 1991 describes the most complex deploy/retrieve mission flown by the shuttle. Another chapter focuses on the Hubble Space Telescope servicing missions. A third chapter gives the reader a detailed look at the February 2010 STS-130 mission to the International Space Station. The fourth chapter answers the question why rendezvous was not completely automated on the Gemini, Apollo, and Space Shuttle vehicles.

Paper Darts

Science.gov (United States)

Tapson, Frank

1974-01-01

Motivation for practicing basic arithmetic skills is provided by activities based on dart board games. There activities also require participants to devise winning strategies, adding enrichment to the game-type drills. (JP)

Short rendezvous missions for advanced Russian human spacecraft

Science.gov (United States)

Murtazin, Rafail F.; Budylov, Sergey G.

2010-10-01

The two-day stay of crew in a limited inhabited volume of the Soyuz-TMA spacecraft till docking to ISS is one of the most stressful parts of space flight. In this paper a number of possible ways to reduce the duration of the free flight phase are considered. The duration is defined by phasing strategy that is necessary for reduction of the phase angle between the chaser and target spacecraft. Some short phasing strategies could be developed. The use of such strategies creates more comfortable flight conditions for crew thanks to short duration and additionally it allows saving spacecraft's life support resources. The transition from the methods of direct spacecraft rendezvous using one orbit phasing (first flights of " Vostok" and " Soyuz" vehicles) to the currently used methods of two-day rendezvous mission can be observed in the history of Soviet manned space program. For an advanced Russian human rated spacecraft the short phasing strategy is recommended, which can be considered as a combination between the direct and two-day rendezvous missions. The following state of the art technologies are assumed available: onboard accurate navigation; onboard computations of phasing maneuvers; launch vehicle with high accuracy injection orbit, etc. Some operational requirements and constraints for the strategies are briefly discussed. In order to provide acceptable phase angles for possible launch dates the experience of the ISS altitude profile control can be used. As examples of the short phasing strategies, the following rendezvous missions are considered: direct ascent, short mission with the phasing during 3-7 orbits depending on the launch date (nominal or backup). For each option statistical modeling of the rendezvous mission is fulfilled, as well as an admissible phase angle range, accuracy of target state vector and addition fuel consumption coming out of emergency is defined. In this paper an estimation of pros and cons of all options is conducted.

Dart essentials

CERN Document Server

Sikora, Martin

2015-01-01

This book is targeted at expert programmers in JavaScript who want to learn Dart quickly. Some previous experience with OOP programming in other languages and a good knowledge of JavaScript are assumed.

DART: New Research Using Ensemble Data Assimilation in Geophysical Models

Science.gov (United States)

Hoar, T. J.; Raeder, K.

2015-12-01

The Data Assimilation Research Testbed (DART) is a community facilityfor ensemble data assimilation developed and supported by the NationalCenter for Atmospheric Research. DART provides a comprehensive suite of software, documentation, and tutorials that can be used for ensemble data assimilation research, operations, and education. Scientists and software engineers at NCAR are available to support DART users who want to use existing DART products or develop their own applications. Current DART users range from university professors teaching data assimilation, to individual graduate students working with simple models, through national laboratories doing operational prediction with large state-of-the-art models. DART runs efficiently on many computational platforms ranging from laptops through thousands of cores on the newest supercomputers.This poster focuses on several recent research activities using DART with geophysical models.Using CAM/DART to understand whether OCO-2 Total Precipitable Water observations can be useful in numerical weather prediction.Impacts of the synergistic use of Infra-red CO retrievals (MOPITT, IASI) in CAM-CHEM/DART assimilations.Assimilation and Analysis of Observations of Amazonian Biomass Burning Emissions by MOPITT (aerosol optical depth), MODIS (carbon monoxide) and MISR (plume height).Long term evaluation of the chemical response of MOPITT-CO assimilation in CAM-CHEM/DART OSSEs for satellite planning and emission inversion capabilities.Improved forward observation operators for land models that have multiple land use/land cover segments in a single grid cell,Simulating mesoscale convective systems (MCSs) using a variable resolution, unstructured grid in the Model for Prediction Across Scales (MPAS) and DART.The mesoscale WRF+DART system generated an ensemble of year-long, real-time initializations of a convection allowing model over the United States.Constraining WACCM with observations in the tropical band (30S-30N) using DART

Virtual reality applications to automated rendezvous and capture

Science.gov (United States)

Hale, Joseph; Oneil, Daniel

Virtual Reality (VR) is a rapidly developing Human/Computer Interface (HCI) technology. The evolution of high-speed graphics processors and development of specialized anthropomorphic user interface devices, that more fully involve the human senses, have enabled VR technology. Recently, the maturity of this technology has reached a level where it can be used as a tool in a variety of applications. This paper provides an overview of: VR technology, VR activities at Marshall Space Flight Center (MSFC), applications of VR to Automated Rendezvous and Capture (AR&C), and identifies areas of VR technology that requires further development.

Automated rendezvous and capture development infrastructure

Science.gov (United States)

Bryan, Thomas C.; Roe, Fred; Coker, Cynthia

1992-01-01

The facilities at Marshall Space Flight Center and JSC to be utilized to develop and test an autonomous rendezvous and capture (ARC) system are described. This includes equipment and personnel facility capabilities to devise, develop, qualify, and integrate ARC elements and subsystems into flight programs. Attention is given to the use of a LEO test facility, the current concept and unique system elements of the ARC, and the options available to develop ARC technology.

Autonomous rendezvous and capture development infrastructure

Science.gov (United States)

Bryan, Thomas C.; Roe, Fred; Coker, Cindy; Nelson, Pam; Johnson, B.

1991-01-01

In the development of the technology for autonomous rendezvous and docking, key infrastructure capabilities must be used for effective and economical development. This involves facility capabilities, both equipment and personnel, to devise, develop, qualify, and integrate ARD elements and subsystems into flight programs. One effective way of reducing technical risks in developing ARD technology is the use of the ultimate test facility, using a Shuttle-based reusable free-flying testbed to perform a Technology Demonstration Test Flight which can be structured to include a variety of additional sensors, control schemes, and operational approaches. This conceptual testbed and flight demonstration will be used to illustrate how technologies and facilities at MSFC can be used to develop and prove an ARD system.

Robust H∞ Control for Spacecraft Rendezvous with a Noncooperative Target

Directory of Open Access Journals (Sweden)

Shu-Nan Wu

2013-01-01

Full Text Available The robust H∞ control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H∞ performance and finite time performance are proposed, and a robust H∞ controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

The function of dart behavior in the paper wasp, Polistes fuscatus.

Science.gov (United States)

Sumana, A; Starks, Philip T

2004-05-01

Dominance behavior in Polistes wasps is a composite trait consisting of various discrete behaviors such as darts, lunges, bites, and mounts. The majority of these behaviors are considered "aggressive", and these aggressive behaviors are considered to form a continuum from mild (e.g., darts) to severe (e.g., falling fights). In this paper we focus on darts, the most common of the dominance behaviors, and investigate their function in un-manipulated post-emergent colonies of the primitively eusocial wasp P. fuscatus. Here we show that darts are correlated with the more severe dominance behaviors, and that dominance ranks do not change with the addition or exclusion of darts. We find no correlation, however, between receiving darts and receiving more severe dominance behaviors. This result suggests that darts are not indicative of aggressive reinforcement of dominance, but rather may serve a different function. Our data suggest that the function of darts is to regulate activity on nests. Both foundresses and workers dart inactive workers significantly more often than by chance, and workers respond to a foundress's (but not a worker's) dart by becoming less inactive. We also found that active workers who receive a dart from either a foundress or worker respond mostly by switching from one activity to another. Thus, our data suggest that darts are not aggressive behaviors, that foundresses use this signal to initiate activity, and that foundresses and workers both use the signal to regulate worker activity.

DART II documentation. Volume III. Appendices

Energy Technology Data Exchange (ETDEWEB)

1979-10-01

The DART II is a remote, interactive, microprocessor-based data acquistion system suitable for use with air monitors. This volume of DART II documentation contains the following appendixes: adjustment and calibration procedures; mother board signature list; schematic diagrams; device specification sheets; ROM program listing; 6800 microprocessor instruction list, octal listing; and cable lists. (RWR)

Two-phase framework for optimal multi-target Lambert rendezvous

OpenAIRE

Bang, Jun; Ahn, Jaemyung

2017-01-01

This paper proposes a two-phase framework to solve an optimal multi-target Lambert rendezvous problem. The first phase solves a series of single-target rendezvous problems for all departure-arrival object pairs to generate the elementary solutions, which provides candidate rendezvous trajectories (elementary solutions). The second phase formulates a variant of traveling salesman problem (TSP) using the elementary solutions prepared in the first phase and determines the best rendezvous sequenc...

Robust H(∞) control for spacecraft rendezvous with a noncooperative target.

Science.gov (United States)

Wu, Shu-Nan; Zhou, Wen-Ya; Tan, Shu-Jun; Wu, Guo-Qiang

2013-01-01

The robust H(∞) control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H(∞) performance and finite time performance are proposed, and a robust H(∞) controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

Comprehensive asynchronous symmetric rendezvous algorithm in ...

Indian Academy of Sciences (India)

Meenu Chawla

2017-11-10

Nov 10, 2017 ... Simulation results affirm that CASR algorithm performs better in terms of average time-to-rendezvous as compared ... process; neighbour discovery; symmetric rendezvous algorithm. 1. .... dezvous in finite time under the symmetric model. The CH ..... CASR algorithm in Matlab 7.11 and performed several.

The DART general equilibrium model: A technical description

OpenAIRE

Springer, Katrin

1998-01-01

This paper provides a technical description of the Dynamic Applied Regional Trade (DART) General Equilibrium Model. The DART model is a recursive dynamic, multi-region, multi-sector computable general equilibrium model. All regions are fully specified and linked by bilateral trade flows. The DART model can be used to project economic activities, energy use and trade flows for each of the specified regions to simulate various trade policy as well as environmental policy scenarios, and to analy...

Fermilab's DART DA system

International Nuclear Information System (INIS)

Pordes, R.; Anderson, J.; Berg, D.; Black, D.; Forster, R.; Franzen, J.; Kent, S.; Kwarciany, R.; Meadows, J.; Moore, C.

1994-04-01

DART is the new data acquisition system designed and implemented for six Fermilab experiments by the Fermilab Computing Division and the experiments themselves. The complexity of the experiments varies greatly. Their data taking throughput and event filtering requirements range from a few (2-5) to tens (80) of CAMAC, FASTBUS and home built front end crates; from a few 100 KByte/sec to 160 MByte/sec front end data collection rates; and from 0-3000 Mips of level 3 processing. The authors report on the architecture and implementation of DART to this date, and the hardware and software components that are being developed and supported

Spacecraft rendezvous and docking

DEFF Research Database (Denmark)

Jørgensen, John Leif

1999-01-01

The phenomenons and problems encountered when a rendezvous manoeuvre, and possible docking, of two spacecrafts has to be performed, have been the topic for numerous studies, and, details of a variety of scenarios has been analysed. So far, all solutions that has been brought into realization has...... been based entirely on direct human supervision and control. This paper describes a vision-based system and methodology, that autonomously generates accurate guidance information that may assist a human operator in performing the tasks associated with both the rendezvous and docking navigation...

Rendezvous effects in the diffusion process on bipartite metapopulation networks.

Science.gov (United States)

Cao, Lang; Li, Xun; Wang, Bing; Aihara, Kazuyuki

2011-10-01

Epidemic outbreaks have been shown to be closely related to the rendezvous-induced transmission of infection, which is caused by casual contact with infected individuals in public gatherings. To investigate rendezvous effects in the spread of infectious diseases, we propose an epidemic model on metapopulation networks bipartite-divided into two sets of location and rendezvous nodes. At a given transition rate γ(kk')(p), each individual transfers from location k to rendezvous p (where rendezvous-induced disease incidence occurs) and thereafter moves to location k'. We find that the eigenstructure of a transition-rate-dependent matrix determines the epidemic threshold condition. Both analytical and numerical results show that rendezvous-induced transmission accelerates the progress of infectious diseases, implying the significance of outbreak control measures including prevention of public gatherings or decentralization of a large-scale rendezvous into downsized ones.

Electro-optical rendezvous and docking sensors

Science.gov (United States)

Tubbs, David J.; Kesler, Lynn O.; Sirko, Robert J.

1991-01-01

Electro-optical sensors provide unique and critical functionality for space missions requiring rendezvous, docking, and berthing. McDonnell Douglas is developing a complete rendezvous and docking system for both manned and unmanned missions. This paper examines our sensor development and the systems and missions which benefit from rendezvous and docking sensors. Simulation results quantifying system performance improvements in key areas are given, with associated sensor performance requirements. A brief review of NASA-funded development activities and the current performance of electro-optical sensors for space applications is given. We will also describe current activities at McDonnell Douglas for a fully functional demonstration to address specific NASA mission needs.

The Double Asteroid Redirection Test (DART)

Science.gov (United States)

Rivkin, A.; Cheng, A. F.; Stickle, A. M.; Richardson, D. C.; Barnouin, O. S.; Thomas, C.; Fahnestock, E.

2017-12-01

The Double Asteroid Redirection Test (DART) will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. DART is currently in Preliminary Design Phase ("Phase B"), and is part of the Asteroid Impact and Deflection Assessment (AIDA), a joint ESA-NASA cooperative project. The AIDA target is the near-Earth binary asteroid 65803 Didymos, an S-class system that will make a close approach to Earth in fall 2022. The DART spacecraft is designed to impact the Didymos secondary at 6 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts. The DART impact on the Didymos secondary will change the orbital period of the binary by several minutes, which can be measured by Earth-based optical and radar observations. The baseline DART mission launches in late 2020 to impact the Didymos secondary in 2022 near the time of its close pass of Earth, which enables an array of ground- and space-based observatories to participate in gathering data. The AIDA project will provide the first measurements of momentum transfer efficiency from hyper-velocity kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are characterized or constrained. The DART kinetic impact is predicted to make a crater of 6 to 17 meters diameter, depending on target physical properties, but will also release a large volume of particulate ejecta that may be directly observable from Earth or even resolvable as a

Improving Access to European E-theses: the DART-Europe Programme

Directory of Open Access Journals (Sweden)

Martin Moyle

2008-11-01

Full Text Available DART-Europe (Digital Access to Research Theses - Europe is a partnership of research libraries and library consortia who are working together to improve global access to European research theses. The Programme is endorsed by LIBER (Ligue des Bibliothèques Européennes de Recherche as part of the work of the LIBER Access Division, and it is the European Working Group of the NDLTD (Networked Digital Library of Theses and Dissertations. DART-Europe serves as a European networking forum on issues relating to electronic theses. The DART-Europe partners share an enthusiasm for open access to research theses, and they have helped to provide researchers with the DART-Europe E-theses Portal, a service which enables the discovery of the open access research-level e-theses offered by institutions and consortia from a growing number of European countries. This article gives an overview of DART-Europe, its progress and its future plans, with particular reference to the DART-Europe E-theses Portal.

Genetic diversity of carotenoid-rich bananas evaluated by Diversity Arrays Technology (DArT

Directory of Open Access Journals (Sweden)

Edson P. Amorim

2009-01-01

Full Text Available The aim of this work was to evaluate the carotenoid content and genetic variability of banana accessions from the Musa germplasm collection held at Embrapa Cassava and Tropical Fruits, Brazil. Forty-two samples were analyzed, including 21 diploids, 19 triploids and two tetraploids. The carotenoid content was analyzed spectrophotometrically and genetic variability was estimated using 653 DArT markers. The average carotenoid content was 4.73 µg.g-1, and ranged from 1.06 µg.g-1 for the triploid Nanica (Cavendish group to 19.24 µg.g-1 for the triploid Saney. The diploids Modok Gier and NBA-14 and the triploid Saney had a carotenoid content that was, respectively, 7-fold, 6-fold and 9-fold greater than that of cultivars from the Cavendish group (2.19 µg.g-1. The mean similarity among the 42 accessions was 0.63 (range: 0.24 to 1.00. DArT analysis revealed extensive genetic variability in accessions from the Embrapa Musa germplasm bank.

Dynamic Acquisition and Retrieval Tool (DART) for Comet Sample Return : Session: 2.06.Robotic Mobility and Sample Acquisition Systems

Science.gov (United States)

Badescu, Mircea; Bonitz, Robert; Kulczycki, Erick; Aisen, Norman; Dandino, Charles M.; Cantrell, Brett S.; Gallagher, William; Shevin, Jesse; Ganino, Anthony; Haddad, Nicolas;

A practical guideline to remote biopsy darting of wildebeests for genetic sampling

Directory of Open Access Journals (Sweden)

Domnic Mijele

2016-12-01

Full Text Available The use of biopsy darts for remote collection of tissue samples from free-ranging terrestrial and aquatic animal species has gained popularity in the recent past. The success of darting is very important since scientists may not have many chances to re-dart the same animal, especially with the free-ranging elusive wildlife species. We used wildebeest (Connochaetes taurinus as a model to estimate the optimum shooting distance, pressure and the shot part of the body through which a researcher can optimize the success and amount of tissue collected from similar wild land mammalian species. Wildebeests were darted at six categories of distances ranging between 10 and 45 m and dart gun pressures of 5–14 millibar. The number of failed darts increased by increasing the darting distance: 0% (10 m, 0% (20 m, 6% (30 m, 20% (35 m, 71% (40 m, and 67% (45 m. There was a notable effect of the distances on the amount of tissue collected 20 m offered the best results. Dart gun pressure had no effect on the amount of tissue samples obtained. The amount of tissue obtained from successful darts was the same whether the animal was darted on the shoulder or thigh. In this paper, we present a practical guideline for remote biopsy darting of wildebeest to obtain optimum amount of tissue samples, which could be generalized for similar wild land mammalian species.

Stepped-to-dart Leaders in Cloud-to-ground Lightning

Science.gov (United States)

Stolzenburg, M.; Marshall, T. C.; Karunarathne, S.; Karunarathna, N.; Warner, T.; Orville, R. E.

2013-12-01

Using time-correlated high-speed video (50,000 frames per second) and fast electric field change (5 MegaSamples per second) data for lightning flashes in East-central Florida, we describe an apparently rare type of subsequent leader: a stepped leader that finds and follows a previously used channel. The observed 'stepped-to-dart leaders' occur in three natural negative ground flashes. Stepped-to-dart leader connection altitudes are 3.3, 1.6 and 0.7 km above ground in the three cases. Prior to the stepped-to-dart connection, the advancing leaders have properties typical of stepped leaders. After the connection, the behavior changes almost immediately (within 40-60 us) to dart or dart-stepped leader, with larger amplitude E-change pulses and faster average propagation speeds. In this presentation, we will also describe the upward luminosity after the connection in the prior return stroke channel and in the stepped leader path, along with properties of the return strokes and other leaders in the three flashes.

Robust H ∞ Control for Spacecraft Rendezvous with a Noncooperative Target

Science.gov (United States)

Wu, Shu-Nan; Zhou, Wen-Ya; Tan, Shu-Jun; Wu, Guo-Qiang

2013-01-01

The robust H ∞ control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H ∞ performance and finite time performance are proposed, and a robust H ∞ controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller. PMID:24027446

Managing Gradual Typing with Message-Safety in Dart

DEFF Research Database (Denmark)

Ernst, Erik; Møller, Anders; Schwarz, Mathias Romme

. This supports evolution from a dynamically typed programto a strictly statically typed form. We present a formal model of Dart that elucidates how a core of the language and its standard type system works. This allows us to characterize message-safe programs and present a theorem stating that such programs......This paper establishes a notion of message-safe programs as a natural intermediate point between dynamically typed and statically typed Dart programs. Unlike traditional static type checking, the type system in the Dart programming language is unsound by design. The rationale has been...... that this allows compile-time detection of likely errors and enables code completion in integrated development environments, without being restrictive on programmers. We show that, despite unsoundness, judicious use of type annotations can ensure useful properties of the runtime behavior of Dart programs...

PREDICTION BASED CHANNEL-HOPPING ALGORITHM FOR RENDEZVOUS IN COGNITIVE RADIO NETWORKS

Directory of Open Access Journals (Sweden)

Dhananjay Kumar

2012-12-01

Full Text Available Most common works for rendezvous in cognitive radio networks deal only with two user scenarios involving two secondary users and variable primary users and aim at reducing the time-to-rendezvous. A common control channel for the establishment of communication is not considered and hence the work comes under the category of ‘Blind Rendezvous’. Our work deal with multi-user scenario and provides a methodology for the users to find each other in the very first time slot spent for rendezvous or otherwise called the firstattempt- rendezvous. The secondary users make use of the history of past communications to enable them to predict the frequency channel that the user expects the rendezvous user to be. Our approach prevents greedy decision making between the users involved by the use of a cut-off time period for attempting rendezvous. Simulation results show that the time-to-rendezvous (TTR is greatly reduced upon comparison with other popular rendezvous algorithms.

DArT whole genome profiling provides insights on the evolution and taxonomy of edible Banana (Musa spp.)

Czech Academy of Sciences Publication Activity Database

Sardos, J.; Perrier, X.; Doležel, Jaroslav; Hřibová, Eva; Christelová, Pavla; Van den Houwe, I.; Kilian, A.; Roux, N.

2016-01-01

Roč. 118, č. 7 (2016), s. 1269-1278 ISSN 0305-7364 R&D Projects: GA MŠk(CZ) LO1204; GA MŠk LG15017 Institutional support: RVO:61389030 Keywords : multilocus genotype data * arrays technology dart * genetic diversity * population-structure * balbisiana colla * acuminata colla * markers * identification * aflp * domestication * Musa acuminata * Musa balbisiana * Musa spp. * banana * DArT * domestication * taxonomy * classification * domestication Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 4.041, year: 2016

Genomic Characterization of DArT Markers Based on High-Density Linkage Analysis and Physical Mapping to the Eucalyptus Genome

Science.gov (United States)

Petroli, César D.; Sansaloni, Carolina P.; Carling, Jason; Steane, Dorothy A.; Vaillancourt, René E.; Myburg, Alexander A.; da Silva, Orzenil Bonfim; Pappas, Georgios Joannis; Kilian, Andrzej; Grattapaglia, Dario

2012-01-01

Diversity Arrays Technology (DArT) provides a robust, high throughput, cost-effective method to query thousands of sequence polymorphisms in a single assay. Despite the extensive use of this genotyping platform for numerous plant species, little is known regarding the sequence attributes and genome-wide distribution of DArT markers. We investigated the genomic properties of the 7,680 DArT marker probes of a Eucalyptus array, by sequencing them, constructing a high density linkage map and carrying out detailed physical mapping analyses to the Eucalyptus grandis reference genome. A consensus linkage map with 2,274 DArT markers anchored to 210 microsatellites and a framework map, with improved support for ordering, displayed extensive collinearity with the genome sequence. Only 1.4 Mbp of the 75 Mbp of still unplaced scaffold sequence was captured by 45 linkage mapped but physically unaligned markers to the 11 main Eucalyptus pseudochromosomes, providing compelling evidence for the quality and completeness of the current Eucalyptus genome assembly. A highly significant correspondence was found between the locations of DArT markers and predicted gene models, while most of the 89 DArT probes unaligned to the genome correspond to sequences likely absent in E. grandis, consistent with the pan-genomic feature of this multi-Eucalyptus species DArT array. These comprehensive linkage-to-physical mapping analyses provide novel data regarding the genomic attributes of DArT markers in plant genomes in general and for Eucalyptus in particular. DArT markers preferentially target the gene space and display a largely homogeneous distribution across the genome, thereby providing superb coverage for mapping and genome-wide applications in breeding and diversity studies. Data reported on these ubiquitous properties of DArT markers will be particularly valuable to researchers working on less-studied crop species who already count on DArT genotyping arrays but for which no reference

Genomic characterization of DArT markers based on high-density linkage analysis and physical mapping to the Eucalyptus genome.

Directory of Open Access Journals (Sweden)

César D Petroli

Full Text Available Diversity Arrays Technology (DArT provides a robust, high throughput, cost-effective method to query thousands of sequence polymorphisms in a single assay. Despite the extensive use of this genotyping platform for numerous plant species, little is known regarding the sequence attributes and genome-wide distribution of DArT markers. We investigated the genomic properties of the 7,680 DArT marker probes of a Eucalyptus array, by sequencing them, constructing a high density linkage map and carrying out detailed physical mapping analyses to the Eucalyptus grandis reference genome. A consensus linkage map with 2,274 DArT markers anchored to 210 microsatellites and a framework map, with improved support for ordering, displayed extensive collinearity with the genome sequence. Only 1.4 Mbp of the 75 Mbp of still unplaced scaffold sequence was captured by 45 linkage mapped but physically unaligned markers to the 11 main Eucalyptus pseudochromosomes, providing compelling evidence for the quality and completeness of the current Eucalyptus genome assembly. A highly significant correspondence was found between the locations of DArT markers and predicted gene models, while most of the 89 DArT probes unaligned to the genome correspond to sequences likely absent in E. grandis, consistent with the pan-genomic feature of this multi-Eucalyptus species DArT array. These comprehensive linkage-to-physical mapping analyses provide novel data regarding the genomic attributes of DArT markers in plant genomes in general and for Eucalyptus in particular. DArT markers preferentially target the gene space and display a largely homogeneous distribution across the genome, thereby providing superb coverage for mapping and genome-wide applications in breeding and diversity studies. Data reported on these ubiquitous properties of DArT markers will be particularly valuable to researchers working on less-studied crop species who already count on DArT genotyping arrays but for

DART: a practical reconstruction algorithm for discrete tomography.

Science.gov (United States)

Batenburg, Kees Joost; Sijbers, Jan

2011-09-01

In this paper, we present an iterative reconstruction algorithm for discrete tomography, called discrete algebraic reconstruction technique (DART). DART can be applied if the scanned object is known to consist of only a few different compositions, each corresponding to a constant gray value in the reconstruction. Prior knowledge of the gray values for each of the compositions is exploited to steer the current reconstruction towards a reconstruction that contains only these gray values. Based on experiments with both simulated CT data and experimental μCT data, it is shown that DART is capable of computing more accurate reconstructions from a small number of projection images, or from a small angular range, than alternative methods. It is also shown that DART can deal effectively with noisy projection data and that the algorithm is robust with respect to errors in the estimation of the gray values.

SpecPad: device-independent NMR data visualization and processing based on the novel DART programming language and Html5 Web technology.

Science.gov (United States)

Guigas, Bruno

2017-09-01

SpecPad is a new device-independent software program for the visualization and processing of one-dimensional and two-dimensional nuclear magnetic resonance (NMR) time domain (FID) and frequency domain (spectrum) data. It is the result of a project to investigate whether the novel programming language DART, in combination with Html5 Web technology, forms a suitable base to write an NMR data evaluation software which runs on modern computing devices such as Android, iOS, and Windows tablets as well as on Windows, Linux, and Mac OS X desktop PCs and notebooks. Another topic of interest is whether this technique also effectively supports the required sophisticated graphical and computational algorithms. SpecPad is device-independent because DART's compiled executable code is JavaScript and can, therefore, be run by the browsers of PCs and tablets. Because of Html5 browser cache technology, SpecPad may be operated off-line. Network access is only required during data import or export, e.g. via a Cloud service, or for software updates. A professional and easy to use graphical user interface consistent across all hardware platforms supports touch screen features on mobile devices for zooming and panning and for NMR-related interactive operations such as phasing, integration, peak picking, or atom assignment. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

An analysis of the survivability of sensor darts in impacts with trees.

Energy Technology Data Exchange (ETDEWEB)

Prentice, John K. (Sci-Tac, Inc., Boulder, CO.); Gardner, David Randall

2005-07-01

A methodology was developed for computing the probability that the sensor dart for the 'Near Real-Time Site Characterization for Assured HDBT Defeat' Grand-Challenge LDRD project will survive deployment over a forested region. The probability can be decomposed into three approximately independent probabilities that account for forest coverage, branch density and the physics of an impact between the dart and a tree branch. The probability that a dart survives an impact with a tree branch was determined from the deflection induced by the impact. If a dart that was deflected so that it impacted the ground at an angle of attack exceeding a user-specified, threshold value, the dart was assumed to not survive the impact with the branch; otherwise it was assumed to have survived. A computer code was developed for calculating dart angle of attack at impact with the ground and a Monte Carlo scheme was used to calculate the probability distribution of a sensor dart surviving an impact with a branch as a function of branch radius, length, and height from the ground. Both an early prototype design and the current dart design were used in these studies. As a general rule of thumb, it we observed that for reasonably generic trees and for a threshold angle of attack of 5{sup o} (which is conservative for dart survival), the probability of reaching the ground with an angle of attack less than the threshold is on the order of 30% for the prototype dart design and 60% for the current dart design, though these numbers should be treated with some caution.

Hyperbolic Rendezvous at Mars: Risk Assessments and Mitigation Strategies

Science.gov (United States)

Jedrey, Ricky; Landau, Damon; Whitley, Ryan

2015-01-01

Given the current interest in the use of flyby trajectories for human Mars exploration, a key requirement is the capability to execute hyperbolic rendezvous. Hyperbolic rendezvous is used to transport crew from a Mars centered orbit, to a transiting Earth bound habitat that does a flyby. Representative cases are taken from future potential missions of this type, and a thorough sensitivity analysis of the hyperbolic rendezvous phase is performed. This includes early engine cutoff, missed burn times, and burn misalignment. A finite burn engine model is applied that assumes the hyperbolic rendezvous phase is done with at least two burns.

Usefulness of combined percutaneous-endoscopic rendezvous techniques after failed therapeutic endoscopic retrograde cholangiography in the era of endoscopic ultrasound guided rendezvous.

Science.gov (United States)

Yang, Min Jae; Kim, Jin Hong; Hwang, Jae Chul; Yoo, Byung Moo; Kim, Soon Sun; Lim, Sun Gyo; Won, Je Hwan

2017-12-01

The rendezvous approach is a salvage technique after failure of endoscopic retrograde cholangiography (ERC). In certain circumstances, percutaneous-endoscopic rendezvous (PE-RV) is preferred, and endoscopic ultrasound-guided rendezvous (EUS-RV) is difficult to perform. We aimed to evaluate PE-RV outcomes, describe the PE-RV techniques, and identify potential indications for PE-RV over EUS-RV.Retrospective analysis was conducted of a prospectively designed ERC database between January 2005 and December 2016 at a tertiary referral center including cases where PE-RV was used as a salvage procedure after ERC failure.During the study period, PE-RV was performed in 42 cases after failed therapeutic ERC; 15 had a surgically altered enteric anatomy. The technical success rate of PE-RV was 92.9% (39/42), with a therapeutic success rate of 88.1% (37/42). Potential indications for PE-RV over EUS-RV were identified in 23 cases, and either PE-RV or EUS-RV could have effectively been used in 19 cases. Endoscopic bile duct access was successfully achieved with PE-RV in 39 cases with accessible biliary orifice using one of PE-RV cannulation techniques (classic, n = 11; parallel, n = 19; and adjunctive maneuvers, n = 9).PE-RV uses a unique technology and has clinical indications that distinguish it from EUS-RV. Therefore, PE-RV can still be considered a useful salvage technique for the treatment of biliary obstruction after ERC failure.

A comparison between DART-MS and DSA-MS in the forensic analysis of writing inks.

Science.gov (United States)

Drury, Nicholas; Ramotowski, Robert; Moini, Mehdi

2018-05-23

Ambient ionization mass spectrometry is gaining momentum in forensic science laboratories because of its high speed of analysis, minimal sample preparation, and information-rich results. One such application of ambient ionization methodology includes the analysis of writing inks from questioned documents where colorants of interest may not be soluble in common solvents, rendering thin layer chromatography (TLC) and separation-mass spectrometry methods such as LC/MS (-MS) impractical. Ambient ionization mass spectrometry uses a variety of ionization techniques such as penning ionization in Direct Analysis in Real Time (DART), and atmospheric pressure chemical ionization in Direct Sample Analysis (DSA), and electrospray ionization in Desorption Electrospray Ionization (DESI). In this manuscript, two of the commonly used ambient ionization techniques are compared: Perkin Elmer DSA-MS and IonSense DART in conjunction with a JEOL AccuTOF MS. Both technologies were equally successful in analyzing writing inks and produced similar spectra. DSA-MS produced less background signal likely because of its closed source configuration; however, the open source configuration of DART-MS provided more flexibility for sample positioning for optimum sensitivity and thereby allowing smaller piece of paper containing writing ink to be analyzed. Under these conditions, the minimum sample required for DART-MS was 1mm strokes of ink on paper, whereas DSA-MS required a minimum of 3mm. Moreover, both techniques showed comparable repeatability. Evaluation of the analytical figures of merit, including sensitivity, linear dynamic range, and repeatability, for DSA-MS and DART-MS analysis is provided. To the forensic context of the technique, DART-MS was applied to the analysis of United States Secret Service ink samples directly on a sampling mesh, and the results were compared with DSA-MS of the same inks on paper. Unlike analysis using separation mass spectrometry, which requires sample

Trajectory control with continuous thrust applied to a rendezvous maneuver

International Nuclear Information System (INIS)

Santos, W G; Rocco, E M

2013-01-01

A rendezvous mission can be divided into the following phases: launch, phasing, far range rendezvous, close range rendezvous and mating (docking or berthing). This paper aims to present a close range rendezvous with closed loop controlled straight line trajectory. The approaching is executed on V-bar axis. A PID controller and continuous thrust are used to eliminate the residual errors in the trajectory. A comparative study about the linear and nonlinear dynamics is performed and the results showed that the linear equations become inaccurate insofar as the chaser moves away from the target

Direct analysis in real time-Mass spectrometry (DART-MS) in forensic and security applications.

Science.gov (United States)

Pavlovich, Matthew J; Musselman, Brian; Hall, Adam B

2018-03-01

Over the last decade, direct analysis in real time (DART) has emerged as a viable method for fast, easy, and reliable "ambient ionization" for forensic analysis. The ability of DART to generate ions from chemicals that might be present at the scene of a criminal activity, whether they are in the gas, liquid, or solid phase, with limited sample preparation has made the technology a useful analytical tool in numerous forensic applications. This review paper summarizes many of those applications, ranging from the analysis of trace evidence to security applications, with a focus on providing the forensic scientist with a resource for developing their own applications. The most common uses for DART in forensics are in studying seized drugs, drugs of abuse and their metabolites, bulk and detonated explosives, toxic chemicals, chemical warfare agents, inks and dyes, and commercial plant and animal products that have been adulterated for economic gain. This review is meant to complement recent reviews that have described the fundamentals of the ionization mechanism and the general use of DART. We describe a wide range of forensic applications beyond the field of analyzing drugs of abuse, which dominates the literature, including common experimental and data analysis methods. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:171-187, 2018. © 2016 Wiley Periodicals, Inc.

DART: Recent Advances in Remote Sensing Data Modeling With Atmosphere, Polarization, and Chlorophyll Fluorescence

Science.gov (United States)

Gastellu-Etchegorry, Jean-Phil; Lauret, Nicolas; Yin, Tiangang; Landier, Lucas; Kallel, Abdelaziz; Malenovsky, Zbynek; Bitar, Ahmad Al; Aval, Josselin; Benhmida, Sahar; Qi, Jianbo;

Use of automated rendezvous trajectory planning to improve spacecraft operations efficiency

Science.gov (United States)

Mulder, Tom A.

1991-01-01

The current planning process for space shuttle rendezvous with a second Earth-orbiting vehicle is time consuming and costly. It is a labor-intensive, manual process performed pre-mission with the aid of specialized maneuver processing tools. Real-time execution of a rendezvous plan must closely follow a predicted trajectory, and targeted solutions leading up to the terminal phase are computed on the ground. Despite over 25 years of Gemini, Apollo, Skylab, and shuttle vehicle-to-vehicle rendezvous missions flown to date, rendezvous in Earth orbit still requires careful monitoring and cannot be taken for granted. For example, a significant trajectory offset was experienced during terminal phase rendezvous of the STS-32 Long Duration Exposure Facility retrieval mission. Several improvements can be introduced to the present rendezvous planning process to reduce costs, produce more fuel-efficient profiles, and increase the probability of mission success.

Trajectory design for a rendezvous mission to Earth's Trojan asteroid 2010 TK7

Science.gov (United States)

Lei, Hanlun; Xu, Bo; Zhang, Lei

2017-12-01

In this paper a rendezvous mission to the Earth's Trojan asteroid 2010 TK7 is proposed, and preliminary transfer trajectories are designed. Due to the high inclination (∼ 20.9°) of the target asteroid relative to the ecliptic plane, direct transfers usually require large amounts of fuel consumption, which is beyond the capacity of current technology. As gravity assist technique could effectively change the inclination of spacecraft's trajectory, it is adopted to reduce the launch energy and rendezvous velocity maneuver. In practical computation, impulsive and low-thrust, gravity-assisted trajectories are considered. Among all the trajectories computed, the low-thrust gravity-assisted trajectory with Venus-Earth-Venus (V-E-V) swingby sequence performs the best in terms of propellant mass. For a spacecraft with initial mass of 800 kg , propellant mass of the best trajectory is 36.74 kg . Numerical results indicate that both the impulsive and low-thrust, gravity-assisted trajectories corresponding to V-E-V sequence could satisfy mission constraints, and can be applied to practical rendezvous mission.

The Evolution of the Rendezvous Profile During the Space Shuttle Program

Science.gov (United States)

Summa, William R.

2010-01-01

The rendezvous and proximity operations approach design techniques for space shuttle missions has changed significantly during the life of the program in response to new requirements that were not part of the original mission design. The flexibility of the shuttle onboard systems design and the mission planning process has allowed the program to meet these requirements. The design of the space shuttle and the shift from docking to grappling with a robotic ann prevented use of legacy Apollo rendezvous techniques. Over the life of the shuttle program the rendezvous profile has evolved due to several factors, including lowering propellant consumption and increasing flexibility in mission planning. Many of the spacecraft that the shuttle rendezvoused with had unique requirements that drove the creation of mission-unique proximity operations. The dockings to the Russian Mir space station and International Space Station (ISS) required further evolution of rendezvous and proximity operations techniques and additional sensors to enhance crew situational awareness. After the Columbia accident, a Rendezvous Pitch Maneuver (RPM) was added to allow tile photography from ISS. Lessons learned from these rendezvous design changes are applicable to future vehicle designs and operations concepts.

Expert system isssues in automated, autonomous space vehicle rendezvous

Science.gov (United States)

Goodwin, Mary Ann; Bochsler, Daniel C.

1987-01-01

The problems involved in automated autonomous rendezvous are briefly reviewed, and the Rendezvous Expert (RENEX) expert system is discussed with reference to its goals, approach used, and knowledge structure and contents. RENEX has been developed to support streamlining operations for the Space Shuttle and Space Station program and to aid definition of mission requirements for the autonomous portions of rendezvous for the Mars Surface Sample Return and Comet Nucleus Sample return unmanned missions. The experience with REMEX to date and recommendations for further development are presented.

Hyperthyroidism with dome-and-dart T wave: A case report

Science.gov (United States)

Lai, Ping; Yuan, Jing-ling; Xue, Jin-hua; Qiu, Yue-qun

2017-01-01

Abstract Rationale: Dome-and-dart T waves (or bifid T waves) are a rare phenomenon in the surface electrocardiogram. These wave forms are mainly observed in patients with congenital heart disease such as atrial septal defect and ventricular septal defect. And hyperthyroidism who presented with an electrocardiogram that had dome-and-dart T waves in a precordial lead is never been reported. Patient concerns: The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Diagnoses: Hyperthyroidism. Interventions: Methimazole. Outcomes: All symptoms were alleviated. Lessons: Dome-and-dart or bifid T waves have been reported in the conventional 12-lead electrocardiograms in some patients with congenital heart disease. The case illustrated here, to the best of our knowledge, dome-and-dart or bifid T waves may associate with hyperthyroidism patients. PMID:28178156

On the mechanism of X-ray production by dart leaders of lightning flashes

Science.gov (United States)

Cooray, Vernon; Dwyer, Joseph; Rakov, V.; Rahman, Mahbubur

2010-07-01

Radiation with energies up to about 250 keV associated with the dart leader phase of rocket-triggered lightning were reported by Dwyer et al. (2004). The mechanism of X-ray generation by dart leaders, however, is unknown at present. Recently, Cooray et al. (2009a) developed physical concepts and mathematical techniques necessary to calculate the electric field associated with the tip of dart leaders. We have utilized the results of these calculations together with the energy dependent frictional force on electrons, as presented by Moss et al. (2006), to evaluate the maximum energy an electron will receive in accelerating in the dart-leader-tip electric field. The main assumptions made in performing the calculations are: (a) the dart leader channel is straight and vertical; (b) the path of the electrons are straight inside the channel; and (c) the decay of the channel temperature is uniform along the length of the dart leader. In the calculation, we have taken into account the fact that the electric field is changing both in space and time and that the gas in the defunct return stroke channel is at atmospheric pressure and at elevated temperature (i.e. reduced gas density). The results of the calculation show that for a given dart leader current there is a critical defunct-return-stroke-channel temperature above which the cold electron runaway becomes feasible. For a typical dart leader, this temperature is around 2500 K. This critical temperature decreases with increase in dart leader current. Since the temperature of the defunct return stroke channel may lie in the range of 2000-4000 K, the results show that the electric field at the tip of dart leaders is capable of accelerating electrons to MeV energy levels.

Combined antegrade and retrograde ureteral stenting: the rendezvous technique

International Nuclear Information System (INIS)

Macri, A.; Magno, C.; Certo, A.; Basile, A.; Scuderi, G.; Crescenti, F.; Famulari, C.

2005-01-01

Ureteral stenting is a routine procedure in endourology. To increase the success rate in difficult cases, it may be helpful to use the rendezvous technique, a combined antegrade and retrograde approach. We performed 16 urological rendezvous in 11 patients with ureteral strictures or urologic lesions. The combined approach was successful in all patients, without morbidity or mortality. In our experience the rendezvous technique increased the success rate of antegrade ureteral stenting from 78.6 to 88.09% (p>0.05). This procedure is a valid option in case of failure of conventional ureteral stenting

An integrated autonomous rendezvous and docking system architecture using Centaur modern avionics

Science.gov (United States)

Nelson, Kurt

1991-01-01

The avionics system for the Centaur upper stage is in the process of being modernized with the current state-of-the-art in strapdown inertial guidance equipment. This equipment includes an integrated flight control processor with a ring laser gyro based inertial guidance system. This inertial navigation unit (INU) uses two MIL-STD-1750A processors and communicates over the MIL-STD-1553B data bus. Commands are translated into load activation through a Remote Control Unit (RCU) which incorporates the use of solid state relays. Also, a programmable data acquisition system replaces separate multiplexer and signal conditioning units. This modern avionics suite is currently being enhanced through independent research and development programs to provide autonomous rendezvous and docking capability using advanced cruise missile image processing technology and integrated GPS navigational aids. A system concept was developed to combine these technologies in order to achieve a fully autonomous rendezvous, docking, and autoland capability. The current system architecture and the evolution of this architecture using advanced modular avionics concepts being pursued for the National Launch System are discussed.

Application of the DART Code for the Assessment of Advanced Fuel Behavior

International Nuclear Information System (INIS)

Rest, J.; Totev, T.

2007-01-01

The Dispersion Analysis Research Tool (DART) code is a dispersion fuel analysis code that contains mechanistically-based fuel and reaction-product swelling models, a one dimensional heat transfer analysis, and mechanical deformation models. DART has been used to simulate the irradiation behavior of uranium oxide, uranium silicide, and uranium molybdenum aluminum dispersion fuels, as well as their monolithic counterparts. The thermal-mechanical DART code has been validated against RERTR tests performed in the ATR for irradiation data on interaction thickness, fuel, matrix, and reaction product volume fractions, and plate thickness changes. The DART fission gas behavior model has been validated against UO 2 fission gas release data as well as measured fission gas-bubble size distributions. Here DART is utilized to analyze various aspects of the observed bubble growth in U-Mo/Al interaction product. (authors)

On-Board Rendezvous Targeting for Orion

Science.gov (United States)

Weeks, Michael W.; DSouza, Christopher N.

2010-01-01

The Orion On-board GNC system is among the most complex ever developed for a space mission. It is designed to operate autonomously (independent of the ground). The rendezvous system in particular was designed to operate on the far side of the moon, and in the case of loss-of-communications with the ground. The vehicle GNC system is designed to retarget the rendezvous maneuvers, given a mission plan. As such, all the maneuvers which will be performed by Orion, have been designed and are being incorporated into the flight code.

Robust Parametric Control of Spacecraft Rendezvous

Directory of Open Access Journals (Sweden)

Dake Gu

2014-01-01

Full Text Available This paper proposes a method to design the robust parametric control for autonomous rendezvous of spacecrafts with the inertial information with uncertainty. We consider model uncertainty of traditional C-W equation to formulate the dynamic model of the relative motion. Based on eigenstructure assignment and model reference theory, a concise control law for spacecraft rendezvous is proposed which could be fixed through solving an optimization problem. The cost function considers the stabilization of the system and other performances. Simulation results illustrate the robustness and effectiveness of the proposed control.

Experimental database retrieval system 'DARTS'

International Nuclear Information System (INIS)

Aoyagi, Tetsuo; Tani, Keiji; Haginoya, Hirobumi; Naito, Shinjiro.

1989-02-01

In JT-60, a large tokamak device of Japan Atomic Energy Research Institute (JAERI), a plasma is fired for 5 ∼ 10 seconds at intervals of about 10 minutes. The each firing is called a shot. Plasma diagnostic data are edited as JT-60 experimental database at every shot cycle and are stored in a large-scale computer (FACOM-M780). Experimentalists look up the data for specific shots which they want to analyze and consider. As the total number of shots increases, they find a difficulty in the looking-up work. In order that they can easily access to their objective shot data or shot group data by using a computer terminal, 'DARTS' (DAtabase ReTrieval System) has been developed. This report may provide enough information on DARTS handling for users. (author)

Remote biopsy darting and marking of polar bears

Science.gov (United States)

Pagano, Anthony M.; Peacock, Elizabeth; McKinney, Melissa A.

2014-01-01

Remote biopsy darting of polar bears (Ursus maritimus) is less invasive and time intensive than physical capture and is therefore useful when capture is challenging or unsafe. We worked with two manufacturers to develop a combination biopsy and marking dart for use on polar bears. We had an 80% success rate of collecting a tissue sample with a single biopsy dart and collected tissue samples from 143 polar bears on land, in water, and on sea ice. Dye marks ensured that 96% of the bears were not resampled during the same sampling period, and we recovered 96% of the darts fired. Biopsy heads with 5 mm diameters collected an average of 0.12 g of fur, tissue, and subcutaneous adipose tissue, while biopsy heads with 7 mm diameters collected an average of 0.32 g. Tissue samples were 99.3% successful (142 of 143 samples) in providing a genetic and sex identification of individuals. We had a 64% success rate collecting adipose tissue and we successfully examined fatty acid signatures in all adipose samples. Adipose lipid content values were lower compared to values from immobilized or harvested polar bears, indicating that our method was not suitable for quantifying adipose lipid content.

Time-Darts: A Data Structure for Verification of Closed Timed Automata

Directory of Open Access Journals (Sweden)

Jiří Srba

2012-11-01

Full Text Available Symbolic data structures for model checking timed systems have been subject to a significant research, with Difference Bound Matrices (DBMs still being the preferred data structure in several mature verification tools. In comparison, discretization offers an easy alternative, with all operations having linear-time complexity in the number of clocks, and yet valid for a large class of closed systems. Unfortunately, fine-grained discretization causes itself a state-space explosion. We introduce a new data structure called time-darts for the symbolic representation of state-spaces of timed automata. Compared with the complete discretization, a single time-dart allows to represent an arbitrary large set of states, yet the time complexity of operations on time-darts remain linear in the number of clocks. We prove the correctness of the suggested reachability algorithm and perform several experiments in order to compare the performance of time-darts and the complete discretization. The main conclusion is that in all our experiments the time-dart method outperforms the complete discretization and it scales significantly better for models with larger constants.

Multi-Agent Rendezvousing with a Finite Set of Candidate Rendezvous Points

NARCIS (Netherlands)

Fang, J.; Morse, A. S.; Cao, M.

2008-01-01

The discrete multi-agent rendezvous problem we consider in this paper is concerned with a specified set of points in the plane, called “dwell-points,” and a set of mobile autonomous agents with limited sensing range. Each agent is initially positioned at some dwell-point, and is able to determine

EUS-guided biliary rendezvous using a short hydrophilic guidewire.

Science.gov (United States)

Dhir, Vinay; Kwek, Boon Eu Andrew; Bhandari, Suryaprakash; Bapat, Mukta; Maydeo, Amit

2011-10-01

BACKGROUND AND STUDY AIMS: EUS-guided rendezvous technique for biliary access requires expert manipulation of the guidewire across the downstream stricture or papilla. Published literature reports usage of the long-wire system to prevent loss of wire during scope exchange. We studied the efficacy of using a short hydrophilic guidewire in EUS-guided rendezvous. PATIENTS AND METHODS: This is a retrospective study conducted in a tertiary care referral centre. 15 patients underwent EUS-guided biliary rendezvous with short wire. EUS-guided transduodenal/transgastric puncture of the biliary system was performed, followed by anterograde placement of a hydrophilic short-wire (260 cm) across the downstream stricture and/or papilla. Retrograde access was then achieved by retrieving the trans-papillary wire, followed by standard ERCP intervention. Main outcome measurements were rates of procedural success and complications. RESULTS: EUS-guided biliary rendezvous was successful in 14 patients (93.3%). Failure was seen in one patient due to a tight malignant biliary stricture. One patient had peri-choledochal bile tracking which did not require any specific treatment. CONCLUSIONS: Short-wire system in EUS-guided biliary rendezvous is highly effective and safe. It is a useful salvage procedure for biliary cannulation in patients with accessible papilla.

DART: A Functional-Level Reconfigurable Architecture for High Energy Efficiency

Directory of Open Access Journals (Sweden)

David Raphaël

2008-01-01

Full Text Available Abstract Flexibility becomes a major concern for the development of multimedia and mobile communication systems, as well as classical high-performance and low-energy consumption constraints. The use of general-purpose processors solves flexibility problems but fails to cope with the increasing demand for energy efficiency. This paper presents the DART architecture based on the functional-level reconfiguration paradigm which allows a significant improvement in energy efficiency. DART is built around a hierarchical interconnection network allowing high flexibility while keeping the power overhead low. To enable specific optimizations, DART supports two modes of reconfiguration. The compilation framework is built using compilation and high-level synthesis techniques. A 3G mobile communication application has been implemented as a proof of concept. The energy distribution within the architecture and the physical implementation are also discussed. Finally, the VLSI design of a 0.13  m CMOS SoC implementing a specialized DART cluster is presented.

DART: A Functional-Level Reconfigurable Architecture for High Energy Efficiency

Directory of Open Access Journals (Sweden)

Sébastien Pillement

2007-12-01

Full Text Available Flexibility becomes a major concern for the development of multimedia and mobile communication systems, as well as classical high-performance and low-energy consumption constraints. The use of general-purpose processors solves flexibility problems but fails to cope with the increasing demand for energy efficiency. This paper presents the DART architecture based on the functional-level reconfiguration paradigm which allows a significant improvement in energy efficiency. DART is built around a hierarchical interconnection network allowing high flexibility while keeping the power overhead low. To enable specific optimizations, DART supports two modes of reconfiguration. The compilation framework is built using compilation and high-level synthesis techniques. A 3G mobile communication application has been implemented as a proof of concept. The energy distribution within the architecture and the physical implementation are also discussed. Finally, the VLSI design of a 0.13 μm CMOS SoC implementing a specialized DART cluster is presented.

Treatment for retained [corrected] common bile duct stones during laparoscopic cholecystectomy: the rendezvous technique.

Science.gov (United States)

Borzellino, Giuseppe; Rodella, Luca; Saladino, Edoardo; Catalano, Filippo; Politi, Leonardo; Minicozzi, Annamaria; Cordiano, Claudio

2010-12-01

To determine the feasibility and efficacy of the laparoscopic intraoperative rendezvous technique for common bile duct stones (CBDS). Case series. Verona University Hospital, Verona, Italy. A total of 110 patients were enrolled in the study; 47 had biliary colic; 39, acute cholecystitis; 19, acute biliary pancreatitis; and 5, acute biliary pancreatitis with associated acute cholecystitis. In all patients, CBDS diagnosis was reached by intraoperative cholangiography. Intraoperative endoscopy with rendezvous performed during laparascopic cholecystectomy for confirmed CBDS; for such a procedure, a transcystic guide wire was positioned into the duodenum. Intraoperative endoscopy with rendezvous was performed for retrieved CBDS during a laparoscopic cholecystectomy. Laparoscopic rendezvous feasibility, morbidity, postprocedure pancreatitis, and mortality. The laparoscopic rendezvous proved to be feasible in 95.5% (105 of 110 patients). The rendezvous failed in 3 cases of successfully performed laparoscopic cholecystectomy, and a conversion of the laparoscopy was needed in 2 cases of successful rendezvous. Two major complications and 2 cases of bleeding were registered after sphincterotomy was successfully performed with rendezvous, and severe acute pancreatitis complicated a traditional sphincterotomy performed after a failed rendezvous. Rendezvous is a feasible option for treatment of CBDS; it allows one to perform only 1 stage of treatment, even in acute cases such as cholecystitis and pancreatitis. Positioning of the guide wire may allow reduced complications secondary to papilla cannulation but not those of the endoscopic sphincterotomy.

Endoscopic retrograde cholangiopancreatography with rendezvous cannulation reduces pancreatic injury.

Science.gov (United States)

Swahn, Fredrik; Regnér, Sara; Enochsson, Lars; Lundell, Lars; Permert, Johan; Nilsson, Magnus; Thorlacius, Henrik; Arnelo, Urban

2013-09-28

To examine whether rendezvous endoscopic retrograde cholangiopancreatography (ERCP) is associated with less pancreatic damage, measured as leakage of proenzymes, than conventional ERCP. Patients (n = 122) with symptomatic gallstone disease, intact papilla and no ongoing inflammation, were prospectively enrolled in this case-control designed study. Eighty-one patients were subjected to laparoscopic cholecystectomy and if intraoperative cholangiography suggested common bile duct stones (CBDS), rendezvous ERCP was performed intraoperatively (n = 40). Patients with a negative cholangiogram constituted the control group (n = 41). Another 41 patients with CBDS, not subjected to surgery, underwent conventional ERCP. Pancreatic proenzymes, procarboxypeptidase B and trypsinogen-2 levels in plasma, were analysed at 0, 4, 8 and 24 h. The proenzymes were determined in-house with a double-antibody enzyme linked immunosorbent assay. Pancreatic amylase was measured by an enzymatic colourimetric modular analyser with the manufacturer's reagents. All samples were blinded at analysis. Post ERCP pancreatitis (PEP) occurred in 3/41 (7%) of the patients cannulated with conventional ERCP and none in the rendezvous group. Increased serum levels indicating pancreatic leakage were significantly higher in the conventional ERCP group compared with the rendezvous ERCP group regarding pancreatic amylase levels in the 4- and 8-h samples (P = 0.0015; P = 0.03), procarboxypeptidase B in the 4- and 8-h samples (P rendezvous cannulation technique compared with patients that underwent cholecystectomy alone (control group). Post procedural concentrations of pancreatic amylase and procarboxypeptidase B were significantly correlated with pancreatic duct cannulation and opacification. Rendezvous ERCP reduces pancreatic enzyme leakage compared with conventional ERCP cannulation technique. Thus, laparo-endoscopic technique can be recommended with the ambition to minimise the risk for post ERCP

Smart darting diffusion Monte Carlo: Applications to lithium ion-Stockmayer clusters

International Nuclear Information System (INIS)

Christensen, H. M.; Jake, L. C.; Curotto, E.

2016-01-01

In a recent investigation [K. Roberts et al., J. Chem. Phys. 136, 074104 (2012)], we have shown that, for a sufficiently complex potential, the Diffusion Monte Carlo (DMC) random walk can become quasiergodic, and we have introduced smart darting-like moves to improve the sampling. In this article, we systematically characterize the bias that smart darting moves introduce in the estimate of the ground state energy of a bosonic system. We then test a simple approach to eliminate completely such bias from the results. The approach is applied for the determination of the ground state of lithium ion-n–dipoles clusters in the n = 8–20 range. For these, the smart darting diffusion Monte Carlo simulations find the same ground state energy and mixed-distribution as the traditional approach for n < 14. In larger systems we find that while the ground state energies agree quantitatively with or without smart darting moves, the mixed-distributions can be significantly different. Some evidence is offered to conclude that introducing smart darting-like moves in traditional DMC simulations may produce a more reliable ground state mixed-distribution.

Smart darting diffusion Monte Carlo: Applications to lithium ion-Stockmayer clusters

Energy Technology Data Exchange (ETDEWEB)

Christensen, H. M.; Jake, L. C.; Curotto, E., E-mail: curotto@arcadia.edu [Department of Chemistry and Physics, Arcadia University, Glenside, Pennsylvania 19038-3295 (United States)

2016-05-07

In a recent investigation [K. Roberts et al., J. Chem. Phys. 136, 074104 (2012)], we have shown that, for a sufficiently complex potential, the Diffusion Monte Carlo (DMC) random walk can become quasiergodic, and we have introduced smart darting-like moves to improve the sampling. In this article, we systematically characterize the bias that smart darting moves introduce in the estimate of the ground state energy of a bosonic system. We then test a simple approach to eliminate completely such bias from the results. The approach is applied for the determination of the ground state of lithium ion-n–dipoles clusters in the n = 8–20 range. For these, the smart darting diffusion Monte Carlo simulations find the same ground state energy and mixed-distribution as the traditional approach for n < 14. In larger systems we find that while the ground state energies agree quantitatively with or without smart darting moves, the mixed-distributions can be significantly different. Some evidence is offered to conclude that introducing smart darting-like moves in traditional DMC simulations may produce a more reliable ground state mixed-distribution.

Reuse, Repurposing and Learning Design--Lessons from the DART Project

Science.gov (United States)

Bond, Stephen T.; Ingram, Caroline; Ryan, Steve

2008-01-01

Digital Anthropological Resources for Teaching (DART) is a major project examining ways in which the use of online learning activities and repositories can enhance the teaching of anthropology and, by extension, other disciplines. This paper reports on one strand of DART activity, the development of customisable learning activities that can be…

Endoskopisk ultralydvejledt rendezvous til intern drænage ved galdevejsobstruktion

DEFF Research Database (Denmark)

Knudsen, Marie Høxbro; Vilmann, Peter; Hassan, Hazem

2015-01-01

Endoscopic ultrasound guided rendezvous for biliary drainage Endoscopic retrograde cholangiography (ERCP) is currently standard treatment for biliary drainage. Endoscopic ultrasound guided rendezvous (EUS-RV) is a novel method to overcome an unsuccessful biliary drainage procedure. Under endoscopic...

A Monocular SLAM Method to Estimate Relative Pose During Satellite Proximity Operations

Science.gov (United States)

2015-03-26

Truth rotation values are obtained from the spot of a laser pointer that is fixed to the CubeSat and points 76 Figure 44. The AFIT 6U CubeSat Air Bearing...Demonstration for Autonomous Rendezvous Technology (DART) spacecraft, which irradiates retro-reflectors of a known orienta- tion with a laser to solve the...minimize the additional sub-system requirements on the spacecraft. Most spacecraft already have star trackers , which use dedicated CPUs to perform stellar

Design and Implementation of the Automated Rendezvous Targeting Algorithms for Orion

Science.gov (United States)

DSouza, Christopher; Weeks, Michael

2010-01-01

The Orion vehicle will be designed to perform several rendezvous missions: rendezvous with the ISS in Low Earth Orbit (LEO), rendezvous with the EDS/Altair in LEO, a contingency rendezvous with the ascent stage of the Altair in Low Lunar Orbit (LLO) and a contingency rendezvous in LLO with the ascent and descent stage in the case of an aborted lunar landing. Therefore, it is not difficult to realize that each of these scenarios imposes different operational, timing, and performance constraints on the GNC system. To this end, a suite of on-board guidance and targeting algorithms have been designed to meet the requirement to perform the rendezvous independent of communications with the ground. This capability is particularly relevant for the lunar missions, some of which may occur on the far side of the moon. This paper will describe these algorithms which are designed to be structured and arranged in such a way so as to be flexible and able to safely perform a wide variety of rendezvous trajectories. The goal of the algorithms is not to merely fly one specific type of canned rendezvous profile. Conversely, it was designed from the start to be general enough such that any type of trajectory profile can be flown.(i.e. a coelliptic profile, a stable orbit rendezvous profile, and a expedited LLO rendezvous profile, etc) all using the same rendezvous suite of algorithms. Each of these profiles makes use of maneuver types which have been designed with dual goals of robustness and performance. They are designed to converge quickly under dispersed conditions and they are designed to perform many of the functions performed on the ground today. The targeting algorithms consist of a phasing maneuver (NC), an altitude adjust maneuver (NH), and plane change maneuver (NPC), a coelliptic maneuver (NSR), a Lambert targeted maneuver, and several multiple-burn targeted maneuvers which combine one of more of these algorithms. The derivation and implementation of each of these

Gossip-based solutions for discrete rendezvous in populations of communicating agents.

Science.gov (United States)

Hollander, Christopher D; Wu, Annie S

2014-01-01

The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal) meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm.

Gossip-based solutions for discrete rendezvous in populations of communicating agents.

Directory of Open Access Journals (Sweden)

Christopher D Hollander

Full Text Available The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm.

Integrated climate modelling at the Kiel Institute for World Economics: The DART Model and its applications

OpenAIRE

Deke, Oliver; Peterson, Sonja

2003-01-01

The aim of this paper is to give an overview over the DART model and its applications. The main focus is on the implementation of climate impacts into DART in the course of coupling DART to the ocean-atmosphere model and on the associated empirical problems. The basic DART model and some applications are presented in the next section. Section 3 describes in detail how the economic impacts of climate change on the agricultural sector and the impact of sea level rise are implemented in DART. Se...

Rendezvous endoscopic recanalization for complete esophageal obstruction.

Science.gov (United States)

Fusco, Stefano; Kratt, Thomas; Gani, Cihan; Stueker, Dietmar; Zips, Daniel; Malek, Nisar P; Goetz, Martin

2018-03-30

Complete esophageal obstruction after (chemo)radiation for head and neck cancers is rare. However, inability to swallow one's own saliva strongly inflicts upon quality of life. Techniques for endoscopic recanalization in complete obstruction are not well established. We assessed the efficacy and safety of rendezvous recanalization. We performed a retrospective review of all patients who underwent endoscopic recanalization of complete proximal esophageal obstruction after radiotherapy between January 2009 and June 2016. Technical success was defined as an ability to pass an endoscope across the recanalized lumen, clinical success by changes in the dysphagia score. Adverse events were recorded prospectively. 19 patients with complete obstruction (dysphagia IV°), all of whom had failed at least one trial of conventional dilatation, underwent recanalization by endoscopic rendezvous, a combined approach through a gastrostomy and perorally under fluoroscopic control. Conscious sedation was used in all patients. In 18/19 patients (94.7%), recanalization was technically successful. In 14/18 patients (77.8%), the post-intervention dysphagia score changed to ≤ II. Three patients had their PEG removed. Factors negatively associated with success were obstruction length of 50 mm; and tumor recurrence for long-term success. No severe complications were recorded. Rendezvous recanalization for complete esophageal obstruction is a reliable and safe method to re-establish luminal patency. Differences between technical and clinical success rates highlight the importance of additional functional factors associated with dysphagia. Given the lack of therapeutic alternatives, rendezvous recanalization is a valid option to improve dysphagia.

Model predictive control for spacecraft rendezvous in elliptical orbit

Science.gov (United States)

Li, Peng; Zhu, Zheng H.

2018-05-01

This paper studies the control of spacecraft rendezvous with attitude stable or spinning targets in an elliptical orbit. The linearized Tschauner-Hempel equation is used to describe the motion of spacecraft and the problem is formulated by model predictive control. The control objective is to maximize control accuracy and smoothness simultaneously to avoid unexpected change or overshoot of trajectory for safe rendezvous. It is achieved by minimizing the weighted summations of control errors and increments. The effects of two sets of horizons (control and predictive horizons) in the model predictive control are examined in terms of fuel consumption, rendezvous time and computational effort. The numerical results show the proposed control strategy is effective.

The Next Generation Advanced Video Guidance Sensor: Flight Heritage and Current Development

Science.gov (United States)

Howard, Richard T.; Bryan, Thomas C.

2009-01-01

The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. This paper presents the flight heritage and results of the sensor technology, some hardware trades for the current sensor, and discusses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the various NGAVGS development units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.

Development and mapping of DArT markers within the Festuca - Lolium complex

Science.gov (United States)

Kopecký, David; Bartoš, Jan; Lukaszewski, Adam J; Baird, James H; Černoch, Vladimír; Kölliker, Roland; Rognli, Odd Arne; Blois, Helene; Caig, Vanessa; Lübberstedt, Thomas; Studer, Bruno; Shaw, Paul; Doležel, Jaroslav; Kilian, Andrzej

2009-01-01

Background Grasses are among the most important and widely cultivated plants on Earth. They provide high quality fodder for livestock, are used for turf and amenity purposes, and play a fundamental role in environment protection. Among cultivated grasses, species within the Festuca-Lolium complex predominate, especially in temperate regions. To facilitate high-throughput genome profiling and genetic mapping within the complex, we have developed a Diversity Arrays Technology (DArT) array for five grass species: F. pratensis, F. arundinacea, F. glaucescens, L. perenne and L. multiflorum. Results The DArTFest array contains 7680 probes derived from methyl-filtered genomic representations. In a first marker discovery experiment performed on 40 genotypes from each species (with the exception of F. glaucescens for which only 7 genotypes were used), we identified 3884 polymorphic markers. The number of DArT markers identified in every single genotype varied from 821 to 1852. To test the usefulness of DArTFest array for physical mapping, DArT markers were assigned to each of the seven chromosomes of F. pratensis using single chromosome substitution lines while recombinants of F. pratensis chromosome 3 were used to allocate the markers to seven chromosome bins. Conclusion The resources developed in this project will facilitate the development of genetic maps in Festuca and Lolium, the analysis on genetic diversity, and the monitoring of the genomic constitution of the Festuca × Lolium hybrids. They will also enable marker-assisted selection for multiple traits or for specific genome regions. PMID:19832973

Mars Sample Return - Launch and Detection Strategies for Orbital Rendezvous

Science.gov (United States)

Woolley, Ryan C.; Mattingly, Richard L.; Riedel, Joseph E.; Sturm, Erick J.

2011-01-01

This study sets forth conceptual mission design strategies for the ascent and rendezvous phase of the proposed NASA/ESA joint Mars Sample Return Campaign. The current notional mission architecture calls for the launch of an acquisition/cache rover in 2018, an orbiter with an Earth return vehicle in 2022, and a fetch rover and ascent vehicle in 2024. Strategies are presented to launch the sample into a coplanar orbit with the Orbiter which facilitate robust optical detection, orbit determination, and rendezvous. Repeating ground track orbits exist at 457 and 572 km which provide multiple launch opportunities with similar geometries for detection and rendezvous.

Mars Sample Return: Launch and Detection Strategies for Orbital Rendezvous

Science.gov (United States)

Woolley, Ryan C.; Mattingly, Richard L.; Riedel, Joseph E.; Sturm, Erick J.

2011-01-01

This study sets forth conceptual mission design strategies for the ascent and rendezvous phase of the proposed NASA/ESA joint Mars Sample Return Campaign. The current notional mission architecture calls for the launch of an acquisition/ caching rover in 2018, an Earth return orbiter in 2022, and a fetch rover with ascent vehicle in 2024. Strategies are presented to launch the sample into a nearly coplanar orbit with the Orbiter which would facilitate robust optical detection, orbit determination, and rendezvous. Repeating ground track orbits existat 457 and 572 km which would provide multiple launch opportunities with similar geometries for detection and rendezvous.

Comparative study of rendezvous techniques in post-liver transplant biliary stricture.

Science.gov (United States)

Chang, Jae Hyuck; Lee, In Seok; Chun, Ho Jong; Choi, Jong Young; Yoon, Seung Kyoo; Kim, Dong Goo; You, Young Kyoung; Choi, Myung-Gyu; Han, Sok Won

2012-11-07

To investigate the usefulness of a new rendezvous technique for placing stents using the Kumpe (KMP) catheter in angulated or twisted biliary strictures. The rendezvous technique was performed in patients with a biliary stricture after living donor liver transplantation (LDLT) who required the exchange of percutaneous transhepatic biliary drainage catheters for inside stents. The rendezvous technique was performed using a guidewire in 19 patients (guidewire group) and using a KMP catheter in another 19 (KMP catheter group). We compared the two groups retrospectively. The baseline characteristics did not differ between the groups. The success rate for placing inside stents was 100% in both groups. A KMP catheter was easier to manipulate than a guidewire. The mean procedure time in the KMP catheter group (1012 s, range: 301-2006 s) was shorter than that in the guidewire group (2037 s, range: 251-6758 s, P = 0.022). The cumulative probabilities corresponding to the procedure time of the two groups were significantly different (P = 0.008). The factors related to procedure time were the rendezvous technique method, the number of inside stents, the operator, and balloon dilation of the stricture (P rendezvous technique method was the only significant factor related to procedure time (P = 0.010). The procedural complications observed included one case of mild acute pancreatitis and one case of acute cholangitis in the guidewire group, and two cases of mild acute pancreatitis in the KMP catheter group. The rendezvous technique involving use of the KMP catheter was a fast and safe method for placing inside stents in patients with LDLT biliary stricture that represents a viable alternative to the guidewire rendezvous technique.

FASTDART - A fast, accurate and friendly version of DART code

International Nuclear Information System (INIS)

Rest, Jeffrey; Taboada, Horacio

2000-01-01

A new enhanced, visual version of DART code is presented. DART is a mechanistic model based code, developed for the performance calculation and assessment of aluminum dispersion fuel. Major issues of this new version are the development of a new, time saving calculation routine, able to be run on PC, a friendly visual input interface and a plotting facility. This version, available for silicide and U-Mo fuels, adds to the classical accuracy of DART models for fuel performance prediction, a faster execution and visual interfaces. It is part of a collaboration agreement between ANL and CNEA in the area of Low Enriched Uranium Advanced Fuels, held by the Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy. (author)

Imaging Flash Lidar for Safe Landing on Solar System Bodies and Spacecraft Rendezvous and Docking

Science.gov (United States)

Amzajerdian, Farzin; Roback, Vincent E.; Bulyshev, Alexander E.; Brewster, Paul F.; Carrion, William A; Pierrottet, Diego F.; Hines, Glenn D.; Petway, Larry B.; Barnes, Bruce W.; Noe, Anna M.

2015-01-01

NASA has been pursuing flash lidar technology for autonomous, safe landing on solar system bodies and for automated rendezvous and docking. During the final stages of the landing from about 1 kilometer to 500 meters above the ground, the flash lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes. The onboard flight computer can then use the 3-D map of terrain to guide the vehicle to a safe location. As an automated rendezvous and docking sensor, the flash lidar can provide relative range, velocity, and bearing from an approaching spacecraft to another spacecraft or a space station. NASA Langley Research Center has developed and demonstrated a flash lidar sensor system capable of generating 16,000 pixels range images with 7 centimeters precision, at 20 Hertz frame rate, from a maximum slant range of 1800 m from the target area. This paper describes the lidar instrument and presents the results of recent flight tests onboard a rocket-propelled free-flyer vehicle (Morpheus) built by NASA Johnson Space Center. The flights were conducted at a simulated lunar terrain site, consisting of realistic hazard features and designated landing areas, built at NASA Kennedy Space Center specifically for this demonstration test. This paper also provides an overview of the plan for continued advancement of the flash lidar technology aimed at enhancing its performance to meet both landing and automated rendezvous and docking applications.

Combined Sector and Channel Hopping Schemes for Efficient Rendezvous in Directional Antenna Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

AbdulMajid M. Al-Mqdashi

2017-01-01

Full Text Available Rendezvous is a prerequisite and important process for secondary users (SUs to establish data communications in cognitive radio networks (CRNs. Recently, there has been a proliferation of different channel hopping- (CH- based schemes that can provide rendezvous without relying on any predetermined common control channel. However, the existing CH schemes were designed with omnidirectional antennas which can degrade their rendezvous performance when applied in CRNs that are highly crowded with primary users (PUs. In such networks, the large number of PUs may lead to the inexistence of any common available channel between neighboring SUs which result in a failure of their rendezvous process. In this paper, we consider the utilization of directional antennas in CRNs for tackling the issue. Firstly, we propose two coprimality-based sector hopping (SH schemes that can provide efficient pairwise sector rendezvous in directional antenna CRNs (DIR-CRNs. Then, we propose an efficient CH scheme that can be combined within the SH schemes for providing a simultaneous sector and channel rendezvous. The guaranteed rendezvous of our schemes are proven by deriving the theoretical upper bounds of their rendezvous delay metrics. Furthermore, extensive simulation comparisons with other related rendezvous schemes are conducted to illustrate the significant outperformance of our schemes.

DaRT: A CALL System to Help Students Practice and Develop Reasoning Skills in Choosing English Articles.

Science.gov (United States)

Yoshii, Rika; Milne, Alastair

1998-01-01

Describes DaRT, a computer assisted language-learning system for helping English-as-a-Second-Language students master English articles. DaRT uses a diagrammatic reasoning tool to present communicative contexts for exercises in choosing appropriate articles. This paper describes the development of DaRT and DaRT's system components and concludes…

DART Core/Combustor-Noise Initial Test Results

Science.gov (United States)

Boyle, Devin K.; Henderson, Brenda S.; Hultgren, Lennart S.

2017-01-01

Contributions from the combustor to the overall propulsion noise of civilian transport aircraft are starting to become important due to turbofan design trends and advances in mitigation of other noise sources. Future propulsion systems for ultra-efficient commercial air vehicles are projected to be of increasingly higher bypass ratio from larger fans combined with much smaller cores, with ultra-clean burning fuel-flexible combustors. Unless effective noise-reduction strategies are developed, combustor noise is likely to become a prominent contributor to overall airport community noise in the future. The new NASA DGEN Aero0propulsion Research Turbofan (DART) is a cost-efficient testbed for the study of core-noise physics and mitigation. This presentation gives a brief description of the recently completed DART core combustor-noise baseline test in the NASA GRC Aero-Acoustic Propulsion Laboratory (AAPL). Acoustic data was simultaneously acquired using the AAPL overhead microphone array in the engine aft quadrant far field, a single midfield microphone, and two semi-infinite-tube unsteady pressure sensors at the core-nozzle exit. An initial assessment shows that the data is of high quality and compares well with results from a quick 2014 feasibility test. Combustor noise components of measured total-noise signatures were educed using a two-signal source-separation method an dare found to occur in the expected frequency range. The research described herein is aligned with the NASA Ultra-Efficient Commercial Transport strategic thrust and is supported by the NASA Advanced Air Vehicle Program, Advanced Air Transport Technology Project, under the Aircraft Noise Reduction Subproject.

Clinical utility of an endoscopic ultrasound-guided rendezvous technique via various approach routes.

Science.gov (United States)

Kawakubo, Kazumichi; Isayama, Hiroyuki; Sasahira, Naoki; Nakai, Yousuke; Kogure, Hirofumi; Hamada, Tsuyoshi; Miyabayashi, Koji; Mizuno, Suguru; Sasaki, Takashi; Ito, Yukiko; Yamamoto, Natsuyo; Hirano, Kenji; Tada, Minoru; Koike, Kazuhiko

2013-09-01

The endoscopic ultrasound-guided rendezvous techniques (EUS-rendezvous) provide reliable biliary access after failed endoscopic retrograde cholangiopancreatography (ERCP) cannulation. We evaluated the clinical utility of an EUS-rendezvous technique using various approach routes. Patients undergoing EUS-rendezvous for biliary access after failed bile duct cannulation in ERCP were included. EUS-rendezvous was performed via three approach routes depending on the patient's condition: transgastric, transduodenal in a short endoscopic position, or transduodenal in a long endoscopic position. The main outcomes were the technical success rates. Secondary outcomes were procedure time and complications. Fourteen patients (median age, 77 years) underwent EUS-rendezvous for biliary access resulting from failed biliary cannulation. The reasons for biliary drainage were malignant biliary obstruction in five patients and choledocholithiasis in nine. Transgastric, transduodenal in a short position, and transduodenal in a long position EUS-rendezvous was performed in five, five, and four patients, respectively. Bile duct puncture occurred in the left intrahepatic duct in four patients, right hepatic duct in one, middle common bile duct in four, and lower common bile duct in five. The technical success rate was 100 %. In four patients, the approach route was modified from transduodenal in a short position to transduodenal in a long position or transgastric route. The median procedure time was 81 min. One case each of biliary peritonitis and pancreatitis occurred and were managed conservatively. EUS-rendezvous provided safe and reliable transpapillary bile duct access after failed ERCP cannulation. The selection of the appropriate approach routes, depending on patient condition, is critical.

A DArT marker genetic map of perennial ryegrass (Lolium perenne L.) integrated with detailed comparative mapping information; comparison with existing DArT marker genetic maps of Lolium perenne, L. multiflorum and Festuca pratensis.

Science.gov (United States)

King, Julie; Thomas, Ann; James, Caron; King, Ian; Armstead, Ian

2013-07-03

Ryegrasses and fescues (genera, Lolium and Festuca) are species of forage and turf grasses which are used widely in agricultural and amenity situations. They are classified within the sub-family Pooideae and so are closely related to Brachypodium distachyon, wheat, barley, rye and oats. Recently, a DArT array has been developed which can be used in generating marker and mapping information for ryegrasses and fescues. This represents a potential common marker set for ryegrass and fescue researchers which can be linked through to comparative genomic information for the grasses. A F2 perennial ryegrass genetic map was developed consisting of 7 linkage groups defined by 1316 markers and deriving a total map length of 683 cM. The marker set included 866 DArT and 315 gene sequence-based markers. Comparison with previous DArT mapping studies in perennial and Italian ryegrass (L. multiflorum) identified 87 and 105 DArT markers in common, respectively, of which 94% and 87% mapped to homoeologous linkage groups. A similar comparison with meadow fescue (F. pratensis) identified only 28 DArT markers in common, of which c. 50% mapped to non-homoelogous linkage groups. In L. perenne, the genetic distance spanned by the DArT markers encompassed the majority of the regions that could be described in terms of comparative genomic relationships with rice, Brachypodium distachyon, and Sorghum bicolor. DArT markers are likely to be a useful common marker resource for ryegrasses and fescues, though the success in aligning different populations through the mapping of common markers will be influenced by degrees of population interrelatedness. The detailed mapping of DArT and gene-based markers in this study potentially allows comparative relationships to be derived in future mapping populations characterised using solely DArT markers.

Drosophila arginine methyltransferase 1 (DART1) is an ecdysone receptor co-repressor

International Nuclear Information System (INIS)

Kimura, Shuhei; Sawatsubashi, Shun; Ito, Saya; Kouzmenko, Alexander; Suzuki, Eriko; Zhao, Yue; Yamagata, Kaoru; Tanabe, Masahiko; Ueda, Takashi; Fujiyama, Sari; Murata, Takuya; Matsukawa, Hiroyuki; Takeyama, Ken-ichi; Yaegashi, Nobuo

2008-01-01

Histone arginine methylation is an epigenetic marker that regulates gene expression by defining the chromatin state. Arginine methyltransferases, therefore, serve as transcriptional co-regulators. However, unlike other transcriptional co-regulators, the physiological roles of arginine methyltransferases are poorly understood. Drosophila arginine methyltransferase 1 (DART1), the mammalian PRMT1 homologue, methylates the arginine residue of histone H4 (H4R3me2). Disruption of DART1 in Drosophila by imprecise P-element excision resulted in low viability during metamorphosis in the pupal stages. In the pupal stage, an ecdysone hormone signal is critical for developmental progression. DART1 interacted with the nuclear ecdysone receptor (EcR) in a ligand-dependent manner, and co-repressed EcR in intact flies. These findings suggest that DART1, a histone arginine methyltransferase, is a co-repressor of EcR that is indispensable for normal pupal development in the intact fly

Development and mapping of DArT markers within the Festuca - Lolium complex

Directory of Open Access Journals (Sweden)

Studer Bruno

2009-10-01

Full Text Available Abstract Background Grasses are among the most important and widely cultivated plants on Earth. They provide high quality fodder for livestock, are used for turf and amenity purposes, and play a fundamental role in environment protection. Among cultivated grasses, species within the Festuca-Lolium complex predominate, especially in temperate regions. To facilitate high-throughput genome profiling and genetic mapping within the complex, we have developed a Diversity Arrays Technology (DArT array for five grass species: F. pratensis, F. arundinacea, F. glaucescens, L. perenne and L. multiflorum. Results The DArTFest array contains 7680 probes derived from methyl-filtered genomic representations. In a first marker discovery experiment performed on 40 genotypes from each species (with the exception of F. glaucescens for which only 7 genotypes were used, we identified 3884 polymorphic markers. The number of DArT markers identified in every single genotype varied from 821 to 1852. To test the usefulness of DArTFest array for physical mapping, DArT markers were assigned to each of the seven chromosomes of F. pratensis using single chromosome substitution lines while recombinants of F. pratensis chromosome 3 were used to allocate the markers to seven chromosome bins. Conclusion The resources developed in this project will facilitate the development of genetic maps in Festuca and Lolium, the analysis on genetic diversity, and the monitoring of the genomic constitution of the Festuca × Lolium hybrids. They will also enable marker-assisted selection for multiple traits or for specific genome regions.

Usage and User Experience of Communication before and during Rendezvous

Science.gov (United States)

Colbert, Martin

2005-01-01

This paper reports a field evaluation of the mobile phone as a "package" of device and services. The evaluation compares 44 university students' usage and user experience of communication before and during rendezvous. During a rendezvous (en route), students rated many aspects of the experience of phone use less favourably than before a rendezvous…

A Study of Control Laws for Microsatellite Rendezvous with a Noncooperative Target

National Research Council Canada - National Science Library

Tschirhart, Troy

2003-01-01

This study investigated the feasibility of using a microsatellite to accomplish an orbital rendezvous with a noncooperative target, with a focus on the control laws necessary for achieving such a rendezvous...

Rendezvous, proximity operations and capture quality function deployment report

Science.gov (United States)

Lamkin, Stephen L. (Editor)

1991-01-01

Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

Rendezvous, proximity operations and capture quality function deployment report

Science.gov (United States)

Lamkin, Stephen L.

1991-12-01

Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

Fatal central venous air embolism: a rare complication of esophageal dilation by rendezvous.

Science.gov (United States)

Zald, Philip B; Andersen, Peter E

2011-03-01

Esophageal dilation by rendezvous is a useful technique for the treatment of complicated esophageal strictures. We present a case of a 74-year-old man with chronic dysphagia caused by a complete cervical esophageal stricture that developed after external beam radiotherapy for treatment of papillary thyroid carcinoma. During attempted dilation using the rendezvous technique, the patient suffered a fatal pulmonary air embolism. The technique of esophageal dilation by rendezvous, complications, and risk factors for development of venous air embolism are discussed. To the best of our knowledge, this is the first report in the literature of fatal venous air embolism after dilation by rendezvous. Copyright © 2009 Wiley Periodicals, Inc.

On the Simulation of the Interception of Lightning Dart Leaders

OpenAIRE

Long, Mengni; Becerra, Marley; Thottappillil, Rajeev

2015-01-01

This paper presents the numerical evaluation of the propagation of positive upward connecting leaders under the influence of lightning dart leaders. The simulation is performed with the self-consistent leader inception and propagation model - SLIM-. An analytical expression is derived for calculating the charge per unit length required to thermalize a new upward leader segment. The simulation is validated with two dart leader attachment events in a lightning triggering experiment reported in ...

Extending DART to meet the data acquisition needs of future experiments at Fermilab

International Nuclear Information System (INIS)

Oleynik, Gene; Pordes, Ruth; Barsotti, Ed

1996-01-01

The DART project at Fermilab is a major collaboration to develop a data acquisition system for multiple experiments. The initial implementation of DART has concentrated on providing working data acquisition systems for the (now eight) collaborating experiments in the next Fixed Target Run. In this paper we discuss aspects of the architecture of DART and how these will allow it to be extended to meet the expected needs of future experiments at Fermilab. We also discuss some ongoing developments within the Fermilab Computing Division towards these new implementations. (author)

Extending DART to meet the data acquisition needs of future experiments at Fermilab

International Nuclear Information System (INIS)

Oleynik, G.; Pordes, R.; Barsotti, E.

1995-10-01

The DART project at Fermilab is a major collaboration to develop a data acquisition system for multiple experiments. The initial implementation of DART has concentrated on providing working data acquisition systems for the (now eight) collaborating experiments in the next Fixed Target Run. In this paper we discuss aspects of the architecture of DART and how these will allow it to be extended to meet the expected needs of future experiments at Fermilab. We also discuss some ongoing developments within the Fermilab Computing Division towards these new implementations

Repeated rendezvous treatment of PTBD and ERCP in patients with recurrent obstructive jaundice.

Science.gov (United States)

Liu, Yingdi; Meng, Jianyun; Wang, Jianhua; Wang, Zhiqiang; Wang, Xiangdong; Linghu, Enqiang; Li, Wen; Yang, Yunsheng

2010-01-01

Repeated applications of rendezvous technique combining percutaneous transhepatic biliary drainage (PTBD) with endoscopic retrograde cholangiopancreatography (ERCP) (PE) in patients with recurrent obstructive jaundice have not been reported. The present study aimed to evaluate treatment effects of this technique in patients who previously received the same rendezvous treatment. Repeated PE rendezvous procedure was performed in 27 patients who received the same procedure previously and had recurrent obstructive jaundice. Twenty-two patients were treated by second-time rendezvous procedure and five patients by third-time. The clinical characteristics and therapeutic effects were retrospectively analyzed. By means of repeated rendezvous technique, 26 patients gained access to the bile duct and were successfully implanted new stents, only one failed with stent implantation. Total serum bilirubin level decreased within one week from 221.89 +/- 64.70 micromol/L to 156.0 +/- 32.2 micromol/L in patients with second-time treatment and from 297.07 +/- 109.12 micromol/L to 238.77 +/- 36.81 micromol/L in patients with third-time treatment. There was no severe complications observed that are associated with repeated PE procedure. Rendezvous procedure of PTBD and ERCP could be used repeatedly and effectively for patients who present recurrent obstructive jaundice after ERCP failure.

Automatic rendezvous and docking systems functional and performance requirements

Science.gov (United States)

1985-01-01

A generalized mission design scheme which utilizes a standard mission profile for all OMV rendezvous operations, recognizes typical operational constraints, and minimizes propellant penalties due to nodal regression effects was developed. This scheme has been used to demonstrate a unified guidance and navigation maneuver processor (the UMP), which supports all mission phases through station-keeping. The initial demonstration version of the Orbital Rendezvous Mission Planner (ORMP) was provided for evaluation purposes, and program operation was discussed.

Percutaneous rendezvous technique for the management of a bile duct injury.

Science.gov (United States)

Meek, James; Fletcher, Savannah; Crumley, Kristen; Culp, W C; Meek, Mary

2018-02-01

The rendezvous technique typically involves combined efforts of interventional radiology, endoscopy, and surgery. It can be done solely percutaneously, whereby the interventionalist gains desired access to one point in the body by approaching it from two different access sites. We present the case of a woman who underwent cholecystectomy complicated by a bile duct injury. A percutaneous rendezvous procedure enabled placement of an internal-external drain from the intrahepatic ducts through the biloma and distal common bile duct and into the duodenum. Thus, a percutaneous rendezvous technique is feasible for managing a bile duct injury when endoscopic retrograde cholangio-pancreatography or percutaneous transhepatic cholangiogram alone has been unsuccessful.

Percutaneous rendezvous technique for the management of a bile duct injury

Directory of Open Access Journals (Sweden)

James Meek, DO

2018-02-01

Full Text Available The rendezvous technique typically involves combined efforts of interventional radiology, endoscopy, and surgery. It can be done solely percutaneously, whereby the interventionalist gains desired access to one point in the body by approaching it from two different access sites. We present the case of a woman who underwent cholecystectomy complicated by a bile duct injury. A percutaneous rendezvous procedure enabled placement of an internal-external drain from the intrahepatic ducts through the biloma and distal common bile duct and into the duodenum. Thus, a percutaneous rendezvous technique is feasible for managing a bile duct injury when endoscopic retrograde cholangio-pancreatography or percutaneous transhepatic cholangiogram alone has been unsuccessful.

Type Soundness in the Dart Programming Language

DEFF Research Database (Denmark)

Strocco, Fabio

Many mainstream programming languages are dynamically typed. This allows for rapid software development and programming flexibility because it gives programmers the freedom to use powerful programming patterns that are not allowed in statically typed programming languages. Nevertheless......, this freedom does not come without drawbacks: static bugs detection, IDE support, and compiler optimization techniques are harder to implement. In the last decades, the research literature and mainstream programming languages have been aiming to reach a trade-off between statically typed and dynamically typed...... languages. We investigate the trade-off, focusing on the area of optional typing, which allows programmers to choose when to use static type checking in parts of pro- grams. Our primary focus is Dart, an optionally typed programming language with a type system that is unsound by design. What makes Dart...

Impact of the Intracoronary Rendezvous technique on coronary angioplasty for chronic total occlusion.

Science.gov (United States)

Nihei, Taro; Yamamoto, Yoshito; Kudo, Shun; Hanawa, Kenichiro; Hasebe, Yuhi; Takagi, Yusuke; Minatoya, Yutaka; Sugi, Masafumi; Shimokawa, Hiroaki

2017-10-01

The Rendezvous technique, which requires bidirectional wiring, is one of the useful methods for improving the success rate of recanalization for chronic total occlusion (CTO) in the field of peripheral intervention. Recently, advanced new devices for percutaneous coronary intervention have enabled us to perform the Rendezvous technique for peripheral as well as for coronary CTO lesions. We used the Intracoronary Rendezvous technique to perform angioplasty for coronary CTO. "Intracoronary Rendezvous" means that Rendezvous was achieved within the CTO lesion. From March 2009 to November 2015, 189 patients underwent CTO angioplasty at our institute, and we treated 10 patients with the Intracoronary Rendezvous technique. This technique involves crossing the Gaia series guidewire to the contralateral Corsair microcatheter located inside the plaque of CTO lesions. The majority of the CTO sites examined were in the proximal RCA (60 %). Lesion length of the occlusion was relatively long (64.4 ± 12.2 mm). Using the biplane imaging system, we were able to control the Gaia guidewires in a specific direction. Furthermore, if the antegrade and retrograde wires can be advanced into contiguous space inside the CTO lesion, we intentionally entered either wire into the contralateral Corsair microcatheter, followed by successful CTO crossing. CTO recanalization was completed for all patients without controlled antegrade retrograde subintimal tracking (CART) or reverse CART. No major complications occurred during hospitalization. These results indicate that the Rendezvous technique, assisted by new devices and a biplane imaging system, represents one of the primary options to achieve successful coronary CTO recanalization.

Totally percutaneous rendezvous techniques for the treatment of bile strictures and leakages.

Science.gov (United States)

De Robertis, Riccardo; Contro, Alberto; Zamboni, Giulia; Mansueto, Giancarlo

2014-04-01

Some challenging pathologic conditions of the biliary tract cannot be treated with endoscopy alone, and a combined approach with rendezvous techniques is frequently needed. Three different totally percutaneous rendezvous techniques were successfully applied in three cases. The rendezvous techniques were performed either with bilateral catheterization of bile ducts to treat a challenging type IV biliary stenosis and iatrogenic biliary damage or with biliary catheterization and percutaneous puncture of the anastomotic loop to treat a biliodigestive anastomosis failure with bile leakage. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

DART model for thermal conductivity of U3Si2 aluminum dispersion fuel

International Nuclear Information System (INIS)

Rest, J.; Snelgrove, J.L.; Hofman, G.L.

1995-09-01

This paper describes the primary physical models that form the basis of the DART model for calculating irradiation-induced changes in the thermal conductivity of aluminium dispersion fuel. DART calculations of fuel swelling, pore closure, and thermal conductivity are compared with measured values

Analysis and Hindcast Experiments of the 2009 Sudden Stratospheric Warming in WACCMX+DART

Science.gov (United States)

Pedatella, N. M.; Liu, H.-L.; Marsh, D. R.; Raeder, K.; Anderson, J. L.; Chau, J. L.; Goncharenko, L. P.; Siddiqui, T. A.

2018-04-01

The ability to perform data assimilation in the Whole Atmosphere Community Climate Model eXtended version (WACCMX) is implemented using the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter. Results are presented demonstrating that WACCMX+DART analysis fields reproduce the middle and upper atmosphere variability during the 2009 major sudden stratospheric warming (SSW) event. Compared to specified dynamics WACCMX, which constrains the meteorology by nudging toward an external reanalysis, the large-scale dynamical variability of the stratosphere, mesosphere, and lower thermosphere is improved in WACCMX+DART. This leads to WACCMX+DART better representing the downward transport of chemical species from the mesosphere into the stratosphere following the SSW. WACCMX+DART also reproduces most aspects of the observed variability in ionosphere total electron content and equatorial vertical plasma drift during the SSW. Hindcast experiments initialized on 5, 10, 15, 20, and 25 January are used to assess the middle and upper atmosphere predictability in WACCMX+DART. A SSW, along with the associated middle and upper atmosphere variability, is initially predicted in the hindcast initialized on 15 January, which is ˜10 days prior to the warming. However, it is not until the hindcast initialized on 20 January that a major SSW is forecast to occur. The hindcast experiments reveal that dominant features of the total electron content can be forecasted ˜10-20 days in advance. This demonstrates that whole atmosphere models that properly account for variability in lower atmosphere forcing can potentially extend the ionosphere-thermosphere forecast range.

DART model for thermal conductivity of U3Si2 Aluminum dispersion fuel

International Nuclear Information System (INIS)

Rest, J.; Snelgrove, J.L.; Hofman, G.L.

2004-01-01

This paper describes the primary physical models that form the basis of the DART model for calculating irradiation-induced changes in the thermal conductivity of aluminum dispersion fuel. DART calculations of fuel swelling, pore closure, and thermal conductivity are compared with measured values. (author)

Hyperthyroidism with dome-and-dart T wave: A case report: A care-compliant article.

Science.gov (United States)

Lai, Ping; Yuan, Jing-Ling; Xue, Jin-Hua; Qiu, Yue-Qun

2017-02-01

Dome-and-dart T waves (or bifid T waves) are a rare phenomenon in the surface electrocardiogram. These wave forms are mainly observed in patients with congenital heart disease such as atrial septal defect and ventricular septal defect. And hyperthyroidism who presented with an electrocardiogram that had dome-and-dart T waves in a precordial lead is never been reported. The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Hyperthyroidism. Methimazole. All symptoms were alleviated. Dome-and-dart or bifid T waves have been reported in the conventional 12-lead electrocardiograms in some patients with congenital heart disease. The case illustrated here, to the best of our knowledge, dome-and-dart or bifid T waves may associate with hyperthyroidism patients.

Modified rendezvous intrahepatic bile duct cannulation technique to pass a PTBD catheter in ERCP.

Science.gov (United States)

Lee, Tae Hoon; Park, Sang-Heum; Lee, Sae Hwan; Lee, Chang-Kyun; Lee, Suck-Ho; Chung, Il-Kwun; Kim, Hong Soo; Kim, Sun-Joo

2010-11-14

The rendezvous procedure combines an endoscopic technique with percutaneous transhepatic biliary drainage (PTBD). When a selective common bile duct cannulation fails, PTBD allows successful drainage and retrograde access for subsequent rendezvous techniques. Traditionally, rendezvous procedures such as the PTBD-assisted over-the-wire cannulation method, or the parallel cannulation technique, may be available when a bile duct cannot be selectively cannulated. When selective intrahepatic bile duct (IHD) cannulation fails, this modified rendezvous technique may be a feasible alternative. We report the case of a modified rendezvous technique, in which the guidewire was retrogradely passed into the IHD through the C2 catheter after end-to-end contact between the tips of the sphincterotome and the C2 catheter at the ampulla's orifice, in a 39-year-old man who had been diagnosed with gallbladder carcinoma with a metastatic right IHD obstruction. Clinically this procedure may be a feasible and timesaving technique.

The Rendezvous Technique for Common Bile Duct Stones: A Meta-Analysis.

Science.gov (United States)

Huang, Long; Yu, Qing-sheng; Zhang, Qi; Liu, Ju-da; Wang, Zhen

2015-12-01

This article aimed to clarify the effectiveness and the efficiency of the rendezvous technique for patients with common bile duct stones. Four databases were searched on associations with rendezvous treatment. Six randomized controlled trials were evaluated for their success rate, stone clearance, morbidity, mortality, conversions, hospital stay, operating time, and hospitalization charges. This meta-analysis suggested no significant difference between the rendezvous group and the sequence group in the success rate and the stone clearance, but showed significant differences in the morbidity [odds ratio (OR)=0.54; 95% confidence intervals (CI), 0.30, 0.96], conversions (OR=0.40; 95% CI, 0.16, 0.97), the length of hospital stay (OR=-1.97; 95% CI, -2.29, -1.66), and the operating time (OR=12.95; 95% CI, 7.66, 18.24). The rendezvous technique is as effective as sequential endoscopic management for patients with common bile duct stones in its success rate and stone clearance, but the former is preferred in terms of morbidity, hospital stay, and hospitalization charges.

Changes in the reproductive system of the snail Helix aspersa caused by mucus from the love dart

NARCIS (Netherlands)

Koene, J M; Chase, R.

The function of the love dart in certain species of terrestrial snails is unknown. In Helix aspersa, the dart is a sharp calcareous structure that is used to pierce the partner's skin during courtship. When expelled, the dart is covered with a thick mucus. The hypothesis tested here is that the

Smart darting diffusion Monte Carlo: Applications to lithium ion-Stockmayer clusters

Science.gov (United States)

Christensen, H. M.; Jake, L. C.; Curotto, E.

2016-05-01

In a recent investigation [K. Roberts et al., J. Chem. Phys. 136, 074104 (2012)], we have shown that, for a sufficiently complex potential, the Diffusion Monte Carlo (DMC) random walk can become quasiergodic, and we have introduced smart darting-like moves to improve the sampling. In this article, we systematically characterize the bias that smart darting moves introduce in the estimate of the ground state energy of a bosonic system. We then test a simple approach to eliminate completely such bias from the results. The approach is applied for the determination of the ground state of lithium ion-n-dipoles clusters in the n = 8-20 range. For these, the smart darting diffusion Monte Carlo simulations find the same ground state energy and mixed-distribution as the traditional approach for n simulations may produce a more reliable ground state mixed-distribution.

Applications of DART-MS for food quality and safety assurance in food supply chain.

Science.gov (United States)

Guo, Tianyang; Yong, Wei; Jin, Yong; Zhang, Liya; Liu, Jiahui; Wang, Sai; Chen, Qilong; Dong, Yiyang; Su, Haijia; Tan, Tianwei

2017-03-01

Direct analysis in real time (DART) represents a new generation of ion source which is used for rapid ionization of small molecules under ambient conditions. The combination of DART and various mass spectrometers allows analyzing multiple food samples with simple or no sample treatment, or in conjunction with prevailing protocolized sample preparation methods. Abundant applications by DART-MS have been reviewed in this paper. The DART-MS strategy applied to food supply chain (FSC), including production, processing, and storage and transportation, provides a comprehensive solution to various food components, contaminants, authenticity, and traceability. Additionally, typical applications available in food analysis by other ambient ionization mass spectrometers were summarized, and fundamentals mainly including mechanisms, devices, and parameters were discussed as well. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:161-187, 2017. © 2015 Wiley Periodicals, Inc.

Early laparoendoscopic rendezvous for acute biliary pancreatitis: preliminary results.

Science.gov (United States)

Borzellino, G; Lombardo, F; Minicozzi, A M; Donataccio, M; Cordiano, C

2010-02-01

Early restored patency of the papilla has been hypothesized to reduce complications and mortality of acute biliary pancreatitis. The aim of this study was to evaluate the role of urgent laparoscopic cholecystectomy with intraoperative cholangiography and rendezvous when necessary in acute biliary pancreatitis natural history. Patients observed in the early stage of an acute biliary pancreatitis were included in the study. Operative risk assessment based on American Society of Anesthesiologists (ASA) score allowed the performance of urgent laparoscopic cholecystectomy within 72 h from onset of symptoms in 55 patients and a delayed intervention during the same admission in 21 patients. Intraoperative cholangiography was performed in all cases, and clearance of common bile duct was performed by flushing when possible, or rendezvous when necessary. Evolution of pancreatitis was evaluated with clinical and radiological monitoring. Urgent laparoscopic cholecystectomy was performed in all cases without conversion. At intraoperative cholangiography common bile duct was free in 25 patients, a papillary spasm was observed in 9, and common bile duct stones in 21 patients. Patency of the papilla was restored by flushing in 13 patients, while a rendezvous was necessary in 17 patients. The rate of organ failure and pancreatic necrosis was 1.8%, overall mortality was 1.8%, and overall morbidity 21.8%. No infectious complications of peripancreatic collections were observed. Urgent laparoscopic cholecystectomy with selective intraoperative rendezvous may be considered as a treatment option in the early stage of acute biliary pancreatitis.

Over-the-catheter precut to gain access to the biliary duct during ERCP rendezvous.

Science.gov (United States)

Manes, Gianpiero; Baratti, Cinzia; Ardizzone, Sandro; Ferla, Fabio; Spiropoulos, Jean; Corsi, Fabio; Foschi, Diego; Trabucchi, Emilio; Bianchi Porro, Gabriele

2008-10-01

Endoscopic retrograde cholangiopancreatography (ERCP) rendezvous during laparoscopic cholecystectomy is an efficient and safe method to treat cholecystocholedocholithiasis. Advancing a guidewire through the cystic duct into the duodenum and withdrawing it in the accessory channel of duodenoscope may be, however, laborious. Moreover, rendezvous performed in the typical manner needs the use of several costly accessories. We herein describe a simpler and cheaper method to gain access to the biliary duct at rendezvous. Twenty-four consecutive patients undergoing ERCP rendezvous during laparoscopic cholecystectomy were considered. A catheter was introduced in the cystic duct and advanced into the duodenum. Access to the bile duct was than achieved by means of a precut sphincterotomy performed over the catheter emerging from the papilla. Cannulation was successful in all but two patients, in whom ERCP was performed in the conventional manner. The only complication was a case of mild post-sphincterotomy bleeding. In comparison with the typical rendezvous technique our procedure allowed savings of about 250, since its performance only requires a catheter and a knife sphincterotome. Over-the-catheter precut during ERCP rendezvous is a feasible and safe method which avoids the need for the manipulation of several accessories and guidewires, and thus results in money and time savings.

Detection of nicotine as an indicator of tobacco smoke by direct analysis in real time (DART) tandem mass spectrometry

Science.gov (United States)

Kuki, Ákos; Nagy, Lajos; Nagy, Tibor; Zsuga, Miklós; Kéki, Sándor

2015-01-01

The residual tobacco smoke contamination (thirdhand smoke, THS) on the clothes of a smoker was examined by direct analysis in real time (DART) mass spectrometry. DART-MS enabled sensitive and selective analysis of nicotine as the indicator of tobacco smoke pollution. Tandem mass spectrometric (MS/MS) experiments were also performed to confirm the identification of nicotine. Transferred thirdhand smoke originated from the fingers of a smoker onto other objects was also detected by DART mass spectrometry. DART-MS/MS was utilized for monitoring the secondhand tobacco smoke (SHS) in the air of the laboratory using nicotine as an indicator. To the best of our knowledge, this is the first report on the application of DART-MS and DART-MS/MS to the detection of thirdhand smoke and to the monitoring of secondhand smoke.

Multiple NEO Rendezvous Using Solar Sails

Science.gov (United States)

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

Mission concept is to assess the feasibility of using solar sail propulsion to enable a robotic precursor that would survey multiple Near Earth Objects (NEOs) for potential future human visits. Single spacecraft will rendezvous with and image 3 NEOs within 6 years of launch

Shared control on lunar spacecraft teleoperation rendezvous operations with large time delay

Science.gov (United States)

Ya-kun, Zhang; Hai-yang, Li; Rui-xue, Huang; Jiang-hui, Liu

2017-08-01

Teleoperation could be used in space on-orbit serving missions, such as object deorbits, spacecraft approaches, and automatic rendezvous and docking back-up systems. Teleoperation rendezvous and docking in lunar orbit may encounter bottlenecks for the inherent time delay in the communication link and the limited measurement accuracy of sensors. Moreover, human intervention is unsuitable in view of the partial communication coverage problem. To solve these problems, a shared control strategy for teleoperation rendezvous and docking is detailed. The control authority in lunar orbital maneuvers that involves two spacecraft as rendezvous and docking in the final phase was discussed in this paper. The predictive display model based on the relative dynamic equations is established to overcome the influence of the large time delay in communication link. We discuss and attempt to prove via consistent, ground-based simulations the relative merits of fully autonomous control mode (i.e., onboard computer-based), fully manual control (i.e., human-driven at the ground station) and shared control mode. The simulation experiments were conducted on the nine-degrees-of-freedom teleoperation rendezvous and docking simulation platform. Simulation results indicated that the shared control methods can overcome the influence of time delay effects. In addition, the docking success probability of shared control method was enhanced compared with automatic and manual modes.

A “Love” Dart Allohormone Identified in the Mucous Glands of Hermaphroditic Land Snails

NARCIS (Netherlands)

Stewart, M.J.; Wang, Tianfang; Koene, J.M.; Storey, K.B.; cummns, S.F.

2016-01-01

Animals have evolved many ways to enhance their own reproductive success. One bizarre sexual ritual is the "love" dart shooting of helicid snails, which has courted many theories regarding its precise function. Acting as a hypodermic needle, the dart transfers an allohormone that increases paternity

Homicide by Sch from a syringe-like dart ejected by a compound crossbow.

Science.gov (United States)

Guo, Wei; Luo, Guochang; Wang, Hao; Meng, Xiangzhi

2015-02-01

The compound crossbow can be used to eject syringe-like dart loaded with poisonous solution. Succinylcholine (Sch) is a short-acting neuromuscular blocker medically used to achieve complete relaxation of muscle for a good intubation condition. Without the help of an artificial respirator, intramuscular injection of a large dose of Sch can paralyze the respiratory muscle and result in the receiver's death. In this paper, we present the homicide case of a young male killed by Sch from a syringe-like dart ejected by a compound crossbow. The subcutaneous and muscular hemorrhages observed around the entry were more severe than that caused by a medical injection. Additionally, other autopsy results showed the external appearance of a pinhole, general asphyxia signs and pathological findings which were not characteristic. The discovery of a syringe-like dart at the scene is the critical clue and reason for analyzing for Sch, which is commonly used to load syringe-like dart to paralyze and steal dog in the countryside of China. Copyright © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

An alternative fabrication method of the dart thrower's motion orthosis (also known as the dart orthosis).

Science.gov (United States)

Schwartz, Deborah A

2016-01-01

To allow safe early wrist motion after wrist injury, this author has modified an earlier version of a dart thrower's motion orthotic device using material that is currently available on the market and an inexpensive paper fastener as the rivet. - KristinValdes, OTD, OT, CHT, Practice Forum Editor. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

What autocorrelation tells us about motor variability: insights from dart throwing.

Directory of Open Access Journals (Sweden)

Robert J van Beers

Full Text Available In sports such as golf and darts it is important that one can produce ballistic movements of an object towards a goal location with as little variability as possible. A factor that influences this variability is the extent to which motor planning is updated from movement to movement based on observed errors. Previous work has shown that for reaching movements, our motor system uses the learning rate (the proportion of an error that is corrected for in the planning of the next movement that is optimal for minimizing the endpoint variability. Here we examined whether the learning rate is hard-wired and therefore automatically optimal, or whether it is optimized through experience. We compared the performance of experienced dart players and beginners in a dart task. A hallmark of the optimal learning rate is that the lag-1 autocorrelation of movement endpoints is zero. We found that the lag-1 autocorrelation of experienced dart players was near zero, implying a near-optimal learning rate, whereas it was negative for beginners, suggesting a larger than optimal learning rate. We conclude that learning rates for trial-by-trial motor learning are optimized through experience. This study also highlights the usefulness of the lag-1 autocorrelation as an index of performance in studying motor-skill learning.

Optimal Non-Coplanar Launch to Quick Rendezvous

National Research Council Canada - National Science Library

Sears, Gregory

1997-01-01

The purpose of this study was to determine the feasibility of launching a Delta Clipper-like vehicle on an optimal, non-coplanar trajectory to rendezvous with an earth orbiting object in one orbit or less...

Flocking and rendezvous in distributed robotics

CERN Document Server

Francis, Bruce A

2016-01-01

This brief describes the coordinated control of groups of robots using only sensory input – and no direct external commands. Furthermore, each robot employs the same local strategy, i.e., there are no leaders, and the text also deals with decentralized control, allowing for cases in which no single robot can sense all the others. One can get intuition for the problem from the natural world, for example, flocking birds. How do they achieve and maintain their flying formation? Recognizing their importance as the most basic coordination tasks for mobile robot networks, the brief details flocking and rendezvous. They are shown to be physical illustrations of emergent behaviors with global consensus arising from local interactions. The authors extend the consideration of these fundamental ideas to describe their operation in flying robots and prompt readers to pursue further research in the field.  Flocking and Rendezvous in Distributed Robotics will provide graduate students a firm grounding in the subject, w...

Rendezvous maneuvers using Genetic Algorithm

International Nuclear Information System (INIS)

Dos Santos, Denílson Paulo Souza; De Almeida Prado, Antônio F Bertachini; Teodoro, Anderson Rodrigo Barretto

2013-01-01

The present paper has the goal of studying orbital maneuvers of Rendezvous, that is an orbital transfer where a spacecraft has to change its orbit to meet with another spacecraft that is travelling in another orbit. This transfer will be accomplished by using a multi-impulsive control. A genetic algorithm is used to find the transfers that have minimum fuel consumption

Tangent Orbital Rendezvous Using Linear Relative Motion with J2 Perturbations

Directory of Open Access Journals (Sweden)

Gang Zhang

2013-01-01

Full Text Available The tangent-impulse coplanar orbit rendezvous problem is studied based on the linear relative motion for J2-perturbed elliptic orbits. There are three cases: (1 only the first impulse is tangent; (2 only the second impulse is tangent; (3 both impulses are tangent. For a given initial impulse point, the first two problems can be transformed into finding all roots of a single variable function about the transfer time, which can be done by the secant method. The bitangent rendezvous problem requires the same solution for the first two problems. By considering the initial coasting time, the bitangent rendezvous solution is obtained with a difference function. A numerical example for two coplanar elliptic orbits with J2 perturbations is given to verify the efficiency of these proposed techniques.

Comet rendezvous mission design using Solar Electric Propulsion

Science.gov (United States)

Sackett, L. L.; Hastrup, R. C.; Yen, C.-W. L.; Wood, L. J.

1979-01-01

A dual comet (Halley Flyby/Tempel 2 Rendezvous) mission, which is planned to be the first to use the Solar Electric Propulsion System (SEPS), is to be launched in 1985. The purpose of this paper is to describe how the mission design attempts to maximize science return while working within spacecraft and other constraints. Science requirements and desires are outlined and specific instruments are considered. Emphasis is on the strategy for operations in the vicinity of Tempel 2, for which a representative profile is described. The mission is planned to extend about one year past initial rendezvous. Because of the large uncertainty in the comet environment the Tempel 2 operations strategy must be highly adaptive.

Development of DArT markers and assessment of diversity in Fusarium oxysporum f. sp. ciceris, wilt pathogen of chickpea (Cicer arietinum L.).

Science.gov (United States)

Sharma, Mamta; Nagavardhini, Avuthu; Thudi, Mahendar; Ghosh, Raju; Pande, Suresh; Varshney, Rajeev K

2014-06-10

Fusarium oxysporum f. sp. ciceris (Foc), the causal agent of Fusarium wilt of chickpea is highly variable and frequent recurrence of virulent forms have affected chickpea production and exhausted valuable genetic resources. The severity and yield losses of Fusarium wilt differ from place to place owing to existence of physiological races among isolates. Diversity study of fungal population associated with a disease plays a major role in understanding and devising better disease control strategies. The advantages of using molecular markers to understand the distribution of genetic diversity in Foc populations is well understood. The recent development of Diversity Arrays Technology (DArT) offers new possibilities to study the diversity in pathogen population. In this study, we developed DArT markers for Foc population, analysed the genetic diversity existing within and among Foc isolates, compared the genotypic and phenotypic diversity and infer the race scenario of Foc in India. We report the successful development of DArT markers for Foc and their utility in genotyping of Foc collections representing five chickpea growing agro-ecological zones of India. The DArT arrays revealed a total 1,813 polymorphic markers with an average genotyping call rate of 91.16% and a scoring reproducibility of 100%. Cluster analysis, principal coordinate analysis and population structure indicated that the different isolates of Foc were partially classified based on geographical source. Diversity in Foc population was compared with the phenotypic variability and it was found that DArT markers were able to group the isolates consistent with its virulence group. A number of race-specific unique and rare alleles were also detected. The present study generated significant information in terms of pathogenic and genetic diversity of Foc which could be used further for development and deployment of region-specific resistant cultivars of chickpea. The DArT markers were proved to be a powerful

Thermomechanical DART code improvements for LEU VHD dispersion and monolithic fuel element analysis

International Nuclear Information System (INIS)

Taboada, H.; Saliba, R.; Moscarda, M.V.; Rest, J.

2005-01-01

A collaboration agreement between ANL/US DOE and CNEA Argentina in the area of Low Enriched Uranium Advanced Fuels has been in place since October 16, 1997 under the Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy. An annex concerning DART code optimization has been operative since February 8, 1999. Previously, as a part of this annex a visual FASTDART version and also a DART THERMAL version were presented during RERTR 2000, 2002 and RERTR 2003 Meetings. During this past year the following activities were completed: Optimization of DART TM code Al diffusion parameters by testing predictions against reliable data from RERTR experiments. Improvements on the 3-D thermo-mechanical version of the code for modeling the irradiation behavior of LEU U-Mo monolithic fuel. Concerning the first point, by means of an optimization of parameters of the Al diffusion through the interaction product theoretical expression, a reasonable agreement between DART temperature calculations with reliable RERTR PIE data was reached. The 3-D thermomechanical code complex is based upon a finite element thermal-elastic code named TERMELAS, and irradiation behavior provided by the DART code. An adequate and progressive process of coupling calculations of both codes at each time step is currently developed. Compatible thermal calculation between both codes was reached. This is the first stage to benchmark and validate against RERTR PIE data the coupling process. (author)

COMPASS Final Report: Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER)

Science.gov (United States)

Oleson, Steven R.; McGuire, Melissa L.

2009-01-01

In this study, the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team completed a design for a multi-asteroid (Nereus and 1996 FG3) sample return capable spacecraft for the NASA In-Space Propulsion Office. The objective of the study was to support technology development and assess the relative benefits of different electric propulsion systems on asteroid sample return design. The design uses a single, heritage Orion solar array (SA) (approx.6.5 kW at 1 AU) to power a single NASA Evolutionary Xenon Thruster ((NEXT) a spare NEXT is carried) to propel a lander to two near Earth asteroids. After landing and gathering science samples, the Solar Electric Propulsion (SEP) vehicle spirals back to Earth where it drops off the first sample s return capsule and performs an Earth flyby to assist the craft in rendezvousing with a second asteroid, which is then sampled. The second sample is returned in a similar fashion. The vehicle, dubbed Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER), easily fits in an Atlas 401 launcher and its cost estimates put the mission in the New Frontier s (NF's) class mission.

Data flow manager for DART

International Nuclear Information System (INIS)

Berg, D.; Black, D.; Slimmer, D.; Engelfried, J.; O'Dell, V.

1994-04-01

The DART Data Flow Manager (dfm) integrates a buffer manager with a requester/provider model for scheduling work on buffers. Buffer lists, representing built events or other data, are queued by service requesters to service providers. Buffers may be either internal (reside on the local node), or external (located elsewhere, e.g., dual ported memory). Internal buffers are managed locally. Wherever possible, dfm moves only addresses of buffers rather than buffers themselves

Ultrafast Screening and Quantitation of Pesticides in Food and Environmental Matrices by Solid-Phase Microextraction-Transmission Mode (SPME-TM) and Direct Analysis in Real Time (DART).

Science.gov (United States)

Gómez-Ríos, Germán Augusto; Gionfriddo, Emanuela; Poole, Justen; Pawliszyn, Janusz

2017-07-05

The direct interface of microextraction technologies to mass spectrometry (MS) has unquestionably revolutionized the speed and efficacy at which complex matrices are analyzed. Solid Phase Micro Extraction-Transmission Mode (SPME-TM) is a technology conceived as an effective synergy between sample preparation and ambient ionization. Succinctly, the device consists of a mesh coated with polymeric particles that extracts analytes of interest present in a given sample matrix. This coated mesh acts as a transmission-mode substrate for Direct Analysis in Real Time (DART), allowing for rapid and efficient thermal desorption/ionization of analytes previously concentrated on the coating, and dramatically lowering the limits of detection attained by sole DART analysis. In this study, we present SPME-TM as a novel tool for the ultrafast enrichment of pesticides present in food and environmental matrices and their quantitative determination by MS via DART ionization. Limits of quantitation in the subnanogram per milliliter range can be attained, while total analysis time does not exceed 2 min per sample. In addition to target information obtained via tandem MS, retrospective studies of the same sample via high-resolution mass spectrometry (HRMS) were accomplished by thermally desorbing a different segment of the microextraction device.

Interstellar rendezvous missions employing fission propulsion systems

International Nuclear Information System (INIS)

Lenard, Roger X.; Lipinski, Ronald J.

2000-01-01

There has been a conventionally held nostrum that fission system specific power and energy content is insufficient to provide the requisite high accelerations and velocities to enable interstellar rendezvous missions within a reasonable fraction of a human lifetime. As a consequence, all forms of alternative mechanisms that are not yet, and may never be technologically feasible, have been proposed, including laser light sails, fusion and antimatter propulsion systems. In previous efforts, [Lenard and Lipinski, 1999] the authors developed an architecture that employs fission power to propel two different concepts: one, an unmanned probe, the other a crewed vehicle to Alpha Centauri within mission times of 47 to 60 years. The first portion of this paper discusses employing a variant of the ''Forward Resupply Runway'' utilizing fission systems to enable both high accelerations and high final velocities necessary for this type of travel. The authors argue that such an architecture, while expensive, is considerably less expensive and technologically risky than other technologically advanced concepts, and, further, provides the ability to explore near-Earth stellar systems out to distances of 8 light years or so. This enables the ability to establish independent human societies which can later expand the domain of human exploration in roughly eight light-year increments even presuming that no further physics or technology breakthroughs or advances occur. In the second portion of the paper, a technology requirement assessment is performed. The authors argue that reasonable to extensive extensions to known technology could enable this revolutionary capability

dataTEL - Datasets for Technology Enhanced Learning

NARCIS (Netherlands)

Drachsler, Hendrik; Verbert, Katrien; Sicilia, Miguel-Angel; Wolpers, Martin; Manouselis, Nikos; Vuorikari, Riina; Lindstaedt, Stefanie; Fischer, Frank

2011-01-01

Drachsler, H., Verbert, K., Sicilia, M. A., Wolpers, M., Manouselis, N., Vuorikari, R., Lindstaedt, S., & Fischer, F. (2011). dataTEL - Datasets for Technology Enhanced Learning. STELLAR Alpine Rendez-Vous White Paper. Alpine Rendez-Vous 2011 White paper collection, Nr. 13., France (2011)

Methodology for Developing a Probabilistic Risk Assessment Model of Spacecraft Rendezvous and Dockings

Science.gov (United States)

Farnham, Steven J., II; Garza, Joel, Jr.; Castillo, Theresa M.; Lutomski, Michael

2011-01-01

In 2007 NASA was preparing to send two new visiting vehicles carrying logistics and propellant to the International Space Station (ISS). These new vehicles were the European Space Agency s (ESA) Automated Transfer Vehicle (ATV), the Jules Verne, and the Japanese Aerospace and Explorations Agency s (JAXA) H-II Transfer Vehicle (HTV). The ISS Program wanted to quantify the increased risk to the ISS from these visiting vehicles. At the time, only the Shuttle, the Soyuz, and the Progress vehicles rendezvoused and docked to the ISS. The increased risk to the ISS was from an increase in vehicle traffic, thereby, increasing the potential catastrophic collision during the rendezvous and the docking or berthing of the spacecraft to the ISS. A universal method of evaluating the risk of rendezvous and docking or berthing was created by the ISS s Risk Team to accommodate the increasing number of rendezvous and docking or berthing operations due to the increasing number of different spacecraft, as well as the future arrival of commercial spacecraft. Before the first docking attempt of ESA's ATV and JAXA's HTV to the ISS, a probabilistic risk model was developed to quantitatively calculate the risk of collision of each spacecraft with the ISS. The 5 rendezvous and docking risk models (Soyuz, Progress, Shuttle, ATV, and HTV) have been used to build and refine the modeling methodology for rendezvous and docking of spacecrafts. This risk modeling methodology will be NASA s basis for evaluating the addition of future ISS visiting spacecrafts hazards, including SpaceX s Dragon, Orbital Science s Cygnus, and NASA s own Orion spacecraft. This paper will describe the methodology used for developing a visiting vehicle risk model.

Characterization of Printing Inks Using DART-Q-TOF-MS and Attenuated Total Reflectance (ATR) FTIR.

Science.gov (United States)

Williamson, Rhett; Raeva, Anna; Almirall, Jose R

2016-05-01

The rise in improved and widely accessible printing technology has resulted in an interest to develop rapid and minimally destructive chemical analytical techniques that can characterize printing inks for forensic document analysis. Chemical characterization of printing inks allows for both discrimination of inks originating from different sources and the association of inks originating from the same source. Direct analysis in real-time mass spectrometry (DART-MS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used in tandem to analyze four different classes of printing inks: inkjets, toners, offset, and intaglio. A total of 319 samples or ~ 80 samples from each class were analyzed directly on a paper substrate using the two methods. DART-MS was found to characterize the semi-volatile polymeric vehicle components, while ATR-FTIR provided chemical information associated with the bulk components of these inks. Complimentary data results in improved discrimination when both techniques are used in succession resulting in >96% discrimination for all toners, 95% for all inkjets, >92% for all offset, and >54% for all intaglio inks. © 2016 American Academy of Forensic Sciences.

Optimal starting conditions for the rendezvous maneuver: Analytical and computational approach

Science.gov (United States)

Ciarcia, Marco

The three-dimensional rendezvous between two spacecraft is considered: a target spacecraft on a circular orbit around the Earth and a chaser spacecraft initially on some elliptical orbit yet to be determined. The chaser spacecraft has variable mass, limited thrust, and its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We seek the time history of the controls in such a way that the propellant mass required to execute the rendezvous maneuver is minimized. Two cases are considered: (i) time-to-rendezvous free and (ii) time-to-rendezvous given, respectively equivalent to (i) free angular travel and (ii) fixed angular travel for the target spacecraft. The above problem has been studied by several authors under the assumption that the initial separation coordinates and the initial separation velocities are given, hence known initial conditions for the chaser spacecraft. In this paper, it is assumed that both the initial separation coordinates and initial separation velocities are free except for the requirement that the initial chaser-to-target distance is given so as to prevent the occurrence of trivial solutions. Two approaches are employed: optimal control formulation (Part A) and mathematical programming formulation (Part B). In Part A, analyses are performed with the multiple-subarc sequential gradient-restoration algorithm for optimal control problems. They show that the fuel-optimal trajectory is zero-bang, namely it is characterized by two subarcs: a long coasting zero-thrust subarc followed by a short powered max-thrust braking subarc. While the thrust direction of the powered subarc is continuously variable for the optimal trajectory, its replacement with a constant (yet optimized) thrust direction produces a very efficient guidance trajectory. Indeed, for all values of the initial distance, the fuel required by the guidance trajectory is within less than one percent of the fuel required

Development and validation of an improved version of the DART code

International Nuclear Information System (INIS)

Taboada, H; Moscarda, M.V.; Markiewicz, M.; Estevez, E.; Rest, J.

2002-01-01

ANL/USDOE and CNEA Argentina have been participating within a SisterLab Program in the area of Low Enriched Uranium Advanced Fuels since October 16, 1997 under the 'Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy'. An annex concerning DART code optimization has been operative since February 8, 1999. Previously, as a part of this annex we developed a visual version of DART named FASTDART for silicide and U-Mo fuels that was presented at the RERTR Meeting in Las Vegas, Nevada. This paper describes several major improvements in the FASTDART code: a thermal calculation subroutine, a fuel particle size distribution subroutine and several visual interfaces for thermal output plotting and particle size input. Using the power history, coolant regime data and fuel dimensions, the new thermal subroutine is able to calculate at each time step the maximum temperature along the z-longitudinal axis as a function of plate/rod morphology (corrosion oxide, cladding, meat, aluminide particle layer, each radial shell of a central fuel particle, and particle center). Calculated temperatures at each time step are coupled to the DART calculation kernel such that swelling processes, volume phase fractions and meat thermal conductivity are calculated synergistically. The new fuel particle size-distribution subroutine is essential in order to determine the evolution of the volume fraction of reaction product. This phase degrades the heat transport by a twofold mechanism: its appearance implies a diminution of aluminium phase and its thermal conductivity is lower than those of fuel and dispersant phase. The new version includes the capability of plotting thermal data output by means of the plate/rod temperature profile at a given irradiation step, and displaying the maximum temperature evolution of each layer. A comparison between the reaction layer thickness and matrix and fuel volume fractions of several RERTR-3 experiment

Percutaneous-endoscopic rendezvous procedure for the management of bile duct injuries after cholecystectomy: short- and long-term outcomes.

Science.gov (United States)

Schreuder, Anne Marthe; Booij, Klaske A C; de Reuver, Philip R; van Delden, Otto M; van Lienden, Krijn P; Besselink, Marc G; Busch, Olivier R; Gouma, Dirk J; Rauws, Erik A J; van Gulik, Thomas M

2018-01-19

 Bile duct injury (BDI) remains a daunting complication of laparoscopic cholecystectomy. In patients with complex BDI, a percutaneous-endoscopic rendezvous procedure may be required to establish bile duct continuity. The aim of this study was to assess short- and long-term outcomes of the rendezvous procedure.  All consecutive patients with BDI referred to our tertiary referral center between 1995 and 2016 were analyzed. A rendezvous procedure was performed when endoscopic or radiologic intervention failed, and when deemed feasible by a dedicated multidisciplinary team including hepatopancreaticobiliary surgeons, gastrointestinal endoscopists, and interventional radiologists. Classification of BDI, technical success of the rendezvous procedure, procedure-related adverse events, and outcomes were assessed.  Among a total of 812 patients, rendezvous was performed in 47 (6 %), 31 (66 %) of whom were diagnosed with complete transection of the bile duct (Amsterdam type D/Strasberg type E injury). The primary success rate of rendezvous was 94 % (44 /47 patients). Overall morbidity was 18 % (10 /55 procedures). No life-threatening adverse events or 90-day mortality occurred. After a median follow-up of 40 months (interquartile range 23 - 54 months), rendezvous was the final successful treatment in 26 /47 patients (55 %). In 14 /47 patients (30 %), rendezvous acted as a bridge to surgery, with hepaticojejunostomy being chosen either primarily or secondarily to treat refractory or relapsing stenosis. In experienced hands, rendezvous was a safe procedure, with a long-term success rate of 55 %. When endoscopic or transhepatic interventions fail to restore bile duct continuity in patients with BDI, rendezvous should be considered, either as definitive treatment or as a bridge to elective surgery. © Georg Thieme Verlag KG Stuttgart · New York.

Interesting rendezvous location in a liver transplantation patient with anastomosis stricture.

Science.gov (United States)

Odemis, Bulent; Oztas, Erkin; Yurdakul, Mehmet; Torun, Serkan; Suna, Nuredtin; Kayacetin, Ertugrul

2014-11-14

An endoscopic or radiologic percutaneous approach may be an initial minimally invasive method for treating biliary strictures after living donor liver transplantation; however, cannulation of biliary strictures is sometimes difficult due to the presence of a sharp or twisted angle within the stricture or a complete stricture. When an angulated or twisted biliary stricture interrupts passage of a guidewire over the stricture, it is difficult to replace the percutaneous biliary drainage catheter with inside stents by endoscopic retrograde cholangiopancreatography. The rendezvous technique can be used to overcome this difficulty. In addition to the classical rendezvous method, in cases with complete transection of the common bile duct a modified technique involving the insertion of a snare into the subhepatic space has been successfully performed. Herein, we report a modified rendezvous technique in the duodenal bulb as an extraordinary location for a patient with duct-to-duct anastomotic complete stricture after liver transplantation.

Trajectory Control of Rendezvous with Maneuver Target Spacecraft

Science.gov (United States)

Zhou, Zhinqiang

2012-01-01

In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

Rendezvous procedure for the treatment of bile leaks and injury following segmental hepatectomy.

Science.gov (United States)

Nasr, John Y; Hashash, Jana G; Orons, Philip; Marsh, Wallis; Slivka, Adam

2013-05-01

Endoscopic retrograde cholangiopancreatography is a minimally invasive procedure used for the evaluation and management of biliary injuries. At times, ERCP fails and percutaneous modalities may be required. Rendezvous procedures are combined endoscopic and percutaneous techniques that have been used to restore anatomic continuity and biliary drainage in cases where retrograde and/or transhepatic access alone has failed either due to anatomic variation or traumatic injury with biloma formation. To assess if the Rendezvous technique plays a role in establishing biliary continuity in patients with a bile leak after segmental hepatectomy. We herby present a series of 3 patients who had complex bile leaks after segmental liver resection and underwent a combined percutaneous and endoscopic Rendezvous procedure to establish biliary continuity. This technique was successful in restoring biliary continuity and avoiding hepaticojejunostomy in 2 of the 3 patients. The Rendezvous technique may play a role in establishing biliary continuity in patients with biliary leak secondary to hepatic surgery. Copyright © 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Deep-ocean Assessment and Reporting of Tsunamis (DART) Stations

Data.gov (United States)

Department of Homeland Security — As part of the U.S. National Tsunami Hazard Mitigation Program (NTHMP), the Deep Ocean Assessment and Reporting of Tsunamis (DART(R)) Project is an ongoing effort to...

Development and mapping of DArT markers within the Festuca - Lolium complex

DEFF Research Database (Denmark)

Kopecký, David; Bartos, Jan; Lukaszewski, Adam J

2009-01-01

Background Grasses are among the most important and widely cultivated plants on Earth. They provide high quality fodder for livestock, are used for turf and amenity purposes, and play a fundamental role in environment protection. Among cultivated grasses, species within the Festuca-Lolium complex...... predominate, especially in temperate regions. To facilitate high-throughput genome profiling and genetic mapping within the complex, we have developed a Diversity Arrays Technology (DArT) array for five grass species: F. pratensis, F. arundinacea, F. glaucescens, L. perenne and L. multiflorum. Results The DAr...

An automated rendezvous and capture system design concept for the cargo transfer vehicle and Space Station Freedom

Science.gov (United States)

Fuchs, Ron; Marsh, Steven

1991-01-01

A rendezvous sensor system concept was developed for the cargo transfer vehicle (CTV) to autonomously rendezvous with and be captured by Space Station Freedom (SSF). The development of requirements, the design of a unique Lockheed developed sensor concept to meet these requirements, and the system design to place this sensor on the CTV and rendezvous with the SSF are described .

Autonomous spacecraft rendezvous and docking

Science.gov (United States)

Tietz, J. C.; Almand, B. J.

A storyboard display is presented which summarizes work done recently in design and simulation of autonomous video rendezvous and docking systems for spacecraft. This display includes: photographs of the simulation hardware, plots of chase vehicle trajectories from simulations, pictures of the docking aid including image processing interpretations, and drawings of the control system strategy. Viewgraph-style sheets on the display bulletin board summarize the simulation objectives, benefits, special considerations, approach, and results.

Observer-Based Robust Control for Spacecraft Rendezvous with Thrust Saturation

Directory of Open Access Journals (Sweden)

Neng Wan

2014-01-01

Full Text Available This paper proposes an observer-based robust guaranteed cost control method for thrust-limited rendezvous in near-circular orbits. Treating the noncircularity of the target orbit as a parametric uncertainty, a linearized motion model derived from the two-body problem is adopted as the controlled plant. Based on this model, a robust guaranteed cost observer-controller is synthesized with a less conservative saturation control law, and sufficient condition for the existence of this observer-based rendezvous controller is derived. Finally, an illustrative example with immeasurable velocity states is presented to demonstrate the advantages and effectiveness of the control scheme.

TVR-DART: A More Robust Algorithm for Discrete Tomography From Limited Projection Data With Automated Gray Value Estimation.

Science.gov (United States)

Xiaodong Zhuge; Palenstijn, Willem Jan; Batenburg, Kees Joost

2016-01-01

In this paper, we present a novel iterative reconstruction algorithm for discrete tomography (DT) named total variation regularized discrete algebraic reconstruction technique (TVR-DART) with automated gray value estimation. This algorithm is more robust and automated than the original DART algorithm, and is aimed at imaging of objects consisting of only a few different material compositions, each corresponding to a different gray value in the reconstruction. By exploiting two types of prior knowledge of the scanned object simultaneously, TVR-DART solves the discrete reconstruction problem within an optimization framework inspired by compressive sensing to steer the current reconstruction toward a solution with the specified number of discrete gray values. The gray values and the thresholds are estimated as the reconstruction improves through iterations. Extensive experiments from simulated data, experimental μCT, and electron tomography data sets show that TVR-DART is capable of providing more accurate reconstruction than existing algorithms under noisy conditions from a small number of projection images and/or from a small angular range. Furthermore, the new algorithm requires less effort on parameter tuning compared with the original DART algorithm. With TVR-DART, we aim to provide the tomography society with an easy-to-use and robust algorithm for DT.

Design Aids for Real-Time Systems (DARTS)

Science.gov (United States)

Szulewski, P. A.

1982-01-01

Design-Aids for Real-Time Systems (DARTS) is a tool that assists in defining embedded computer systems through tree structured graphics, military standard documentation support, and various analyses including automated Software Science parameter counting and metrics calculation. These analyses provide both static and dynamic design quality feedback which can potentially aid in producing efficient, high quality software systems.

Three homicides with darts tainted with succinylcholine: autopsy and toxicology.

Science.gov (United States)

Xing, Jingjun; Li, Wenhe; Tong, Fang; Liang, Yue; He, Guanglong; Zhou, Yiwu

2016-11-01

In emergency departments, intoxication with the muscle relaxant succinylcholine (SUX) often leads to a potentially lethal respiratory paralysis or other deleterious side effects. However, homicide cases with SUX poisoning are very rare because the toxic or lethal concentration ranges of SUX have not yet been determined. We described three uncommon homicide cases due to acute poisoning by darts contaminated with SUX. All the victims died quickly (less than 30 min) after being shot by an especially designed dart gun. Succinylmonocholine (SMC), a metabolite of SUX, was used as a marker to detect the latter. HPLC-MS/MS analysis demonstrated the presence of SUX in the droplet residues of the darts and SMC in the blood and urine in all cases. SMC concentrations of 0.45, 14.0, and 17.9 ng/ml were detected in the victims' blood and 259.0 ng/ml in the urine from the third case. The main pathological changes consisted of hemorrhage of the injured soft tissues, visceral congestion, severe pulmonary edema, and multifocal petechial hemorrhage of the heart and lungs. Taken together, the findings supported a diagnosis of fatal SUX poisoning. Futhermore, our study provided a reference for the lethal concentrations of SUX poisoning.

The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity.

Science.gov (United States)

Kimura, Kazuki; Chiba, Satoshi

2015-04-07

Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Assessing direct analysis in real-time-mass spectrometry (DART-MS) for the rapid identification of additives in food packaging.

Science.gov (United States)

Ackerman, L K; Noonan, G O; Begley, T H

2009-12-01

The ambient ionization technique direct analysis in real time (DART) was characterized and evaluated for the screening of food packaging for the presence of packaging additives using a benchtop mass spectrometer (MS). Approximate optimum conditions were determined for 13 common food-packaging additives, including plasticizers, anti-oxidants, colorants, grease-proofers, and ultraviolet light stabilizers. Method sensitivity and linearity were evaluated using solutions and characterized polymer samples. Additionally, the response of a model additive (di-ethyl-hexyl-phthalate) was examined across a range of sample positions, DART, and MS conditions (temperature, voltage and helium flow). Under optimal conditions, molecular ion (M+H+) was the major ion for most additives. Additive responses were highly sensitive to sample and DART source orientation, as well as to DART flow rates, temperatures, and MS inlet voltages, respectively. DART-MS response was neither consistently linear nor quantitative in this setting, and sensitivity varied by additive. All additives studied were rapidly identified in multiple food-packaging materials by DART-MS/MS, suggesting this technique can be used to screen food packaging rapidly. However, method sensitivity and quantitation requires further study and improvement.

DART code optimization works

International Nuclear Information System (INIS)

Taboada, Horacio; Solis, Diego

1999-01-01

DART (Dispersion Analysis Research Tool) calculation and assessment program is a thermomechanical computer model developed by Dr. J. Rest of Argonne National Laboratory, USA. This program is the only mechanistic model available to assure the performance of low-enriched oxided-based dispersion fuels, dispersion of siliciures and uranium intermetallics in aluminum matrix for research reactors. The program predicts fission-products induced swelling (especially gases), fuel behavior during fabrication porosity closing, macroscopical changes in diameter of rods or width of plates and tubes produced by fuel deformation, degradation of thermal conductivity of fuel dispersion owing to irradiation and fuel restructuring because of Al-fuel reaction, amorphization and recrystallization. (author)

Deep-Ocean Assessment and Reporting of Tsunamis (DART(R))

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — As part of the U.S. National Tsunami Hazard Mitigation Program (NTHMP), the Deep Ocean Assessment and Reporting of Tsunamis (DART(R)) Project is an ongoing effort to...

Guidance and Navigation for Rendezvous and Proximity Operations with a Non-Cooperative Spacecraft at Geosynchronous Orbit

Science.gov (United States)

Barbee, Brent William; Carpenter, J. Russell; Heatwole, Scott; Markley, F. Landis; Moreau, Michael; Naasz, Bo J.; VanEepoel, John

2010-01-01

The feasibility and benefits of various spacecraft servicing concepts are currently being assessed, and all require that the servicer spacecraft perform rendezvous, proximity, and capture operations with the target spacecraft to be serviced. Many high-value spacecraft, which would be logical targets for servicing from an economic point of view, are located in geosynchronous orbit, a regime in which autonomous rendezvous and capture operations are not commonplace. Furthermore, existing GEO spacecraft were not designed to be serviced. Most do not have cooperative relative navigation sensors or docking features, and some servicing applications, such as de-orbiting of a non-functional spacecraft, entail rendezvous and capture with a spacecraft that may be non-functional or un-controlled. Several of these challenges have been explored via the design of a notional mission in which a nonfunctional satellite in geosynchronous orbit is captured by a servicer spacecraft and boosted into super-synchronous orbit for safe disposal. A strategy for autonomous rendezvous, proximity operations, and capture is developed, and the Orbit Determination Toolbox (ODTBX) is used to perform a relative navigation simulation to assess the feasibility of performing the rendezvous using a combination of angles-only and range measurements. Additionally, a method for designing efficient orbital rendezvous sequences for multiple target spacecraft is utilized to examine the capabilities of a servicer spacecraft to service multiple targets during the course of a single mission.

Robust Tracking Control for Rendezvous in Near-Circular Orbits

Directory of Open Access Journals (Sweden)

Neng Wan

2013-01-01

Full Text Available This paper investigates a robust guaranteed cost tracking control problem for thrust-limited spacecraft rendezvous in near-circular orbits. Relative motion model is established based on the two-body problem with noncircularity of the target orbit described as a parameter uncertainty. A guaranteed cost tracking controller with input saturation is designed via a linear matrix inequality (LMI method, and sufficient conditions for the existence of the robust tracking controller are derived, which is more concise and less conservative compared with the previous works. Numerical examples are provided for both time-invariant and time-variant reference signals to illustrate the effectiveness of the proposed control scheme when applied to the terminal rendezvous and other astronautic missions with scheduled states signal.

Intra-urinoma Rendezvous Using a Transconduit Approach to Re-establish Ureteric Integrity

International Nuclear Information System (INIS)

Anderson, Hugh; Alyas, Faisal; Edwin, Patrick Joseph

2005-01-01

Ureteric discontinuity following injury has been traditionally treated surgically. With the advent of improved interventional instrumentation it is possible to stent these lesions percutaneously, retrogradely or failing that using a combined (rendezvous) technique. We describe an intra-urinoma rendezvous procedure combining a percutaneous antegrade-transconduit retrograde technique of stent insertion to successfully re-establish ureteric integrity that was used following the failure of a percutaneous retrograde approach. We illustrate its usefulness as an alternative to surgery

Run control techniques for the Fermilab DART data acquisition system

International Nuclear Information System (INIS)

Oleynik, G.; Engelfried, J.; Mengel, L.; Moore, C.; Pordes, R.; Udumula, L.; Votava, M.; Drunen, E. van; Zioulas, G.

1996-01-01

DART is the high speed, Unix based data acquisition system being developed by the Fermilab Computing Division in collaboration with eight High Energy Physics Experiments. This paper describes DART run-control which implements flexible, distributed, extensible and portable paradigms for the control monitoring of a data acquisition systems. We discuss the unique and interesting aspects of the run-control - why we chose the concepts we did, the benefits we have seen from the choices we made, as well as our experiences in deploying and supporting it for experiments during their commissioning and sub-system testing phases. We emphasize the software and techniques we believe are extensible to future use, and potential future modifications and extensions for those we feel are not. (author)

Run control techniques for the Fermilab DART data acquisition system

International Nuclear Information System (INIS)

Oleynik, G.; Engelfried, J.; Mengel, L.

1995-10-01

DART is the high speed, Unix based data acquisition system being developed by the Fermilab Computing Division in collaboration with eight High Energy Physics Experiments. This paper describes DART run-control which implements flexible, distributed, extensible and portable paradigms for the control and monitoring of data acquisition systems. We discuss the unique and interesting aspects of the run-control - why we chose the concepts we did, the benefits we have seen from the choices we made, as well as our experiences in deploying and supporting it for experiments during their commissioning and sub-system testing phases. We emphasize the software and techniques we believe are extensible to future use, and potential future modifications and extensions for those we feel are not

The Effect of Air Drag in Optimal Power-Limited Rendezvous Between Coplanar Low-Earth Orbits

Directory of Open Access Journals (Sweden)

Gil-Young Maeng

1998-06-01

Full Text Available The effect of air drag was researched when a low-earth orbit spacecraft using power-limited thruster rendezvoused another low-earth orbit spacecraft. The air density was assumed to decrease exponentially. The radius of parking orbit was 6655.935 km and that of target orbit was 7321.529 km. From the trajectories of active vehicles, the fuel consumption and the magnitude of thrust acceleration, we could conclude that the effect of air drag had to be considered in fuel optimal rendezvous problem between low-earth orbit spacecrafts. In multiple-revolution rendezvous case, the air drag was more effective.

Satellite Servicing's Autonomous Rendezvous and Docking Testbed on the International Space Station

Science.gov (United States)

Naasz, Bo J.; Strube, Matthew; Van Eepoel, John; Barbee, Brent W.; Getzandanner, Kenneth M.

2011-01-01

The Space Servicing Capabilities Project (SSCP) at NASA's Goddard Space Flight Center (GSFC) has been tasked with developing systems for servicing space assets. Starting in 2009, the SSCP completed a study documenting potential customers and the business case for servicing, as well as defining several notional missions and required technologies. In 2010, SSCP moved to the implementation stage by completing several ground demonstrations and commencing development of two International Space Station (ISS) payloads-the Robotic Refueling Mission (RRM) and the Dextre Pointing Package (DPP)--to mitigate new technology risks for a robotic mission to service existing assets in geosynchronous orbit. This paper introduces the DPP, scheduled to fly in July of 2012 on the third operational SpaceX Dragon mission, and its Autonomous Rendezvous and Docking (AR&D) instruments. The combination of sensors and advanced avionics provide valuable on-orbit demonstrations of essential technologies for servicing existing vehicles, both cooperative and non-cooperative.

Comparison of EUS-guided rendezvous and precut papillotomy techniques for biliary access (with videos).

Science.gov (United States)

Dhir, Vinay; Bhandari, Suryaprakash; Bapat, Mukta; Maydeo, Amit

2012-02-01

Precut papillotomy after failed bile duct cannulation is associated with an increased risk of pancreatitis. EUS-guided rendezvous drainage is a novel alternative technique, but there are no data comparing this approach with precut papillotomy. To evaluate the safety and efficacy of EUS-guided rendezvous drainage of the bile duct and compare its outcome with that of precut papillotomy. Retrospective study. Tertiary care referral center. Consecutive patients with distal bile duct obstruction, in whom selective cannulation of the bile duct at ERCP failed after 5 attempts with a guidewire and sphincterotome, underwent an EUS-guided rendezvous procedure. The outcomes were compared with those in a historical cohort of patients who underwent precut papillotomy. Patients in whom selective cannulation failed underwent EUS-guided rendezvous drainage by use of the short wire technique or precut papillotomy by use of the Erlangen papillotome. At EUS, after the extrahepatic bile duct was punctured with a 19-gauge needle, a hydrophilic angled-tip guidewire 260 cm long was passed in an antegrade manner across the papilla into the duodenum. The echoendoscope was then exchanged for a duodenoscope, which was introduced alongside the EUS-placed guidewire. The transpapillary guidewire was retrieved through its biopsy channel, and accessories were passed over the wire to perform the requisite endotherapy. Comparison of the rates of technical success and complications between patients treated by the EUS-guided rendezvous and those treated by precut papillotomy techniques. Treatment success was defined as completion of the requisite endotherapy in one treatment session. Treatment success was significantly higher for the EUS-guided rendezvous (57/58 patients) than for those undergoing precut papillotomy technique (130/144 patients) (98.3% vs 90.3%; P = .03). There was no significant difference in the rate of procedural complications between the EUS and precut papillotomy techniques (3

Deep Interior: Multiple-Rendezvous Prospecting of NEOs

Science.gov (United States)

Kakuda, R. Y.; Asphaug, E.; Belton, M. J. S.; Gulkis, S.; Huebner, W. F.

2000-10-01

from dormancy by explosions. NEO Diversity. Assess the diversity of the interior structures in two classes of near-Earth objects. New Technology. SEP, first multiple rendezvous, autonav, first grenades. Precursor to geoseismic investigations.

Population structure revealed by different marker types (SSR or DArT) has an impact on the results of genome-wide association mapping in European barley cultivars

NARCIS (Netherlands)

Matthies, I.E.; Hintum, van T.J.L.; Weise, S.; Röder, M.S.

2012-01-01

Diversity arrays technology (DArT) and simple sequence repeat (SSR) markers were applied to investigate population structure, extent of linkage disequilibrium and genetic diversity (kinship) on a genome-wide level in European barley (Hordeum vulgare L.) cultivars. A set of 183 varieties could be

Electromagnetic model of a lightning dart leader in the earth atmosphere

International Nuclear Information System (INIS)

Gordeev, A.V.; Losseva, T.V.

2005-01-01

The fundamentally new approach to the lightning dart leader structure investigation is suggested, which is connected with the charge separation and the appearance of the Hall potential in the current-channel magnetic field of the lightning dart leader. Generation of the strong radial electric field provides both the relativistic electron drift along the lightning channel and the breakdown in the Earth atmosphere at the front of the propagating filament. The magnetic selfinsulation in the current channel ensures the propagation of the current filament with the relativistic electrons up to the Earth surface. After this stage the reflected magnetic selfinsulation wave realizes the return stroke stage of the lightning that is accompanied by the strong gas heating in the lightning channel. The current data in the lightning dart leader channel (4-11 kA) and the range of the X-ray emission from the lightning channel (30-250 keV), which are obtained in in-situ observations, are in reasonably good agreement with the estimates made in the frame of this model. Profiles of magnetic field Bq, electron concentration ne, electron velocity v ez and radial electric field E r in current channel for the current value 11 kA are presented. (author)

Proximity Operations and Docking Sensor Development

Science.gov (United States)

Howard, Richard T.; Bryan, Thomas C.; Brewster, Linda L.; Lee, James E.

2009-01-01

The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been under development for the last three years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in spot mode out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. 12 Parts obsolescence issues prevent the construction of more AVGS units, and the next generation sensor was updated to allow it to support the CEV and COTS programs. The flight proven AR&D sensor has been redesigned to update parts and add additional capabilities for CEV and COTS with the development of the Next Generation AVGS at the Marshall Space Flight Center. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities include greater sensor range, auto ranging capability, and real-time video output. This paper presents some sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements

Phylogenetic Relationships between Four Salix L. Species Based on DArT Markers

Directory of Open Access Journals (Sweden)

Jerzy A. Przyborowski

2013-12-01

Full Text Available The objectives of this study were to evaluate the usefulness of DArT markers in genotypic identification of willow species and describe genetic relationships between four willow species: Salix viminalis, S. purpurea, S. alba and S. triandra. The experimental plant material comprised 53 willow genotypes of these four species, which are popularly grown in Poland. DArT markers seem to identify Salix species with a high degree of accuracy. As a result, the examined species were divided into four distinct groups which corresponded to the four analyzed species. In our study, we observed that S. triandra was very different genetically from the other species, including S. alba which is generally classified into the same subgenus of Salix. The above corroborates the findings of other authors who relied on molecular methods to reveal that the classification of S. triandra to the subgenus Salix was erroneous. The Principal Coordinate Analysis (PCoA and the neighbor-joining dendrogram also confirmed the clear division of the studied willow genotypes into four clusters corresponding to individual species. This confirmed the usefulness of DArT markers in taxonomic analyses and identification of willow species.

A Review of Tiangong-1/Shenzhou-8 Rendezvous and Docking Mission%天宫一号／神舟八号交会对接任务总体评述

Institute of Scientific and Technical Information of China (English)

周建平

2012-01-01

The complete success of Tiangong-1/Shenzhou-8 rendezvous and docking mission represents a great breakthrough of China in space rendezvous and docking technology. A basic introduction of Tiangong-land Shenzhou-8 rendezvous and docking mission is presented, with the general evaluation of the mission and its main achievements being put forward.%天宫一号／神舟八号交会对接任务圆满成功，标志着我国空间交会对接技术取得重大突破。本文介绍了天宫一号目标飞行器与神舟八号飞船交会对接飞行任务的基本情况、总体评价及主要成果。

Optimal Rendezvous and Docking Simulator for Elliptical Orbits, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — It is proposed to develop and implement a simulation of spacecraft rendezvous and docking guidance, navigation, and control in elliptical orbit. The foundation of...

Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission

Science.gov (United States)

Hinkel, Heather; Strube, Matthew; Zipay, John J.; Cryan, Scott

2016-01-01

This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR&D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR&D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion spacecraft. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build-time instead of at design-time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal non-recurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current

Transfer of motor and perceptual skills from basketball to darts

Directory of Open Access Journals (Sweden)

Rebecca eRienhoff

2013-09-01

Full Text Available The quiet eye is a perceptual skill associated with expertise and superior performance; however, little is known about the transfer of quiet eye across domains. We attempted to replicate previous skill-based differences in quiet eye and investigated whether transfer of motor and perceptual skills occurs between similar tasks. Throwing accuracy and quiet eye duration for skilled and less-skilled basketball players were examined in basketball free throw shooting and the transfer task of dart throwing. Skilled basketball players showed significantly higher throwing accuracy and longer quiet eye duration in the basketball free throw task compared to their less-skilled counterparts. Further, skilled basketball players showed positive transfer from basketball to dart throwing in accuracy but not in quiet eye duration. Our results raise interesting questions regarding the measurement of transfer between skills.

Recent developments in the field of arrow and dart poisons.

Science.gov (United States)

Philippe, Geneviève; Angenot, Luc

2005-08-22

Arrow and dart poisons, considered as conventional natural sources for future drug discovery, have already provided numerous biologically active molecules used as drugs in therapeutic applications or in pharmacological research. Plants containing alkaloids or cardiotonic glycosides have generally been the main ingredients responsible for the efficacy of these poisons, although some animals, such as frogs, have also been employed. This paper, without being exhaustive, reports the greater strides made during the past 15 years in the understanding of the chemical nature and biological properties of arrow and dart poison constituents. Examples both of promising biological properties shown by these molecules and of crucial discoveries achieved by their use as pharmacological tools are given. Further studies of these toxic principles are likely to enable scientists to find new valuable lead compounds, useful in many fields of research, like oncology, inflammation and infectious diseases.

A MITgcm/DART ensemble analysis and prediction system with application to the Gulf of Mexico

KAUST Repository

Hoteit, Ibrahim

2013-09-01

This paper describes the development of an advanced ensemble Kalman filter (EnKF)-based ocean data assimilation system for prediction of the evolution of the loop current in the Gulf of Mexico (GoM). The system integrates the Data Assimilation Research Testbed (DART) assimilation package with the Massachusetts Institute of Technology ocean general circulation model (MITgcm). The MITgcm/DART system supports the assimilation of a wide range of ocean observations and uses an ensemble approach to solve the nonlinear assimilation problems. The GoM prediction system was implemented with an eddy-resolving 1/10th degree configuration of the MITgcm. Assimilation experiments were performed over a 6-month period between May and October during a strong loop current event in 1999. The model was sequentially constrained with weekly satellite sea surface temperature and altimetry data. Experiments results suggest that the ensemble-based assimilation system shows a high predictive skill in the GoM, with estimated ensemble spread mainly concentrated around the front of the loop current. Further analysis of the system estimates demonstrates that the ensemble assimilation accurately reproduces the observed features without imposing any negative impact on the dynamical balance of the system. Results from sensitivity experiments with respect to the ensemble filter parameters are also presented and discussed. © 2013 Elsevier B.V.

The Single Needle Lockstitch Machine. [Constructing Darts.] Module 3.

Science.gov (United States)

South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

This module on constructing darts, one in a series on the single needle lockstitch sewing machine for student self-study, contains two sections. Each section includes the following parts: an introduction, directions, an objective, learning activities, student information, student self-check, check-out activities, and an instructor's final…

Optimization of Spacecraft Rendezvous and Docking using Interval Analysis

NARCIS (Netherlands)

Van Kampen, E.; Chu, Q.P.; Mulder, J.A.

2010-01-01

This paper applies interval optimization to the fixed-time multiple impulse rendezvous and docking problem. Current methods for solving this type of optimization problem include for example genetic algorithms and gradient based optimization. Unlike these methods, interval methods can guarantee that

Efficacy of dart or booster vaccination with strain RB51 in protecting bison against experimental Brucella abortus challenge

Science.gov (United States)

Vaccination is an effective tool for reducing the prevalence of brucellosis in natural hosts. In this study, we characterized the efficacy of the Brucella abortus strain RB51 (RB51) vaccine in bison when delivered by single intramuscular vaccination (Hand RB51), single pneumatic dart delivery (Dart ...

DART model for irradiation-induced swelling of dispersion fuel elements including aluminum-fuel interaction

International Nuclear Information System (INIS)

Rest, J.; Hofman, G.L.

1997-01-01

The Dispersion Analysis Research Tool (DART) contains models for fission-gas-induced fuel swelling, interaction of fuel with the matrix aluminum, for the resultant reaction-product swelling, and for the calculation of the stress gradient within the fuel particle. The effects of an aluminide shell on fuel particle swelling are evaluated. Validation of the model is demonstrated by a comparison of DART calculations of fuel swelling of U 3 SiAl-Al and U 3 Si 2 -Al for various dispersion fuel element designs with the data

Rendezvous and Docking Strategy for Crewed Segment of the Asteroid Redirect Mission

Science.gov (United States)

Hinkel, Heather D.; Cryan, Scott P.; D'Souza, Christopher; Dannemiller, David P.; Brazzel, Jack P.; Condon, Gerald L.; Othon, William L.; Williams, Jacob

2014-01-01

This paper will describe the overall rendezvous, proximity operations and docking (RPOD) strategy in support of the Asteroid Redirect Crewed Mission (ARCM), as part of the Asteroid Redirect Mission (ARM). The focus of the paper is on the crewed mission phase of ARM, starting with the establishment of Orion in the Distant Retrograde Orbit (DRO) and ending with docking to the Asteroid Redirect Vechicle (ARV). The paper will detail the sequence of maneuvers required to execute the rendezvous and proximity operations mission phases along with the on-board navigation strategies, including the final approach phase. The trajectories to be considered will include target vehicles in a DRO. The paper will also discuss the sensor requirements for rendezvous and docking and the various trade studies associated with the final sensor selection. Building on the sensor requirements and trade studies, the paper will include a candidate sensor concept of operations, which will drive the selection of the sensor suite; concurrently, it will be driven by higher level requirements on the system, such as crew timeline constraints and vehicle consummables. This paper will address how many of the seemingly competing requirements will have to be addressed to create a complete system and system design. The objective is to determine a sensor suite and trajectories that enable Orion to successfully rendezvous and dock with a target vehicle in trans lunar space. Finally, the paper will report on the status of a NASA action to look for synergy within RPOD, across the crewed and robotic asteroid missions.

Quorum system and random based asynchronous rendezvous protocol for cognitive radio ad hoc networks

Directory of Open Access Journals (Sweden)

Sylwia Romaszko

2013-12-01

Full Text Available This paper proposes a rendezvous protocol for cognitive radio ad hoc networks, RAC2E-gQS, which utilizes (1 the asynchronous and randomness properties of the RAC2E protocol, and (2 channel mapping protocol, based on a grid Quorum System (gQS, and taking into account channel heterogeneity and asymmetric channel views. We show that the combination of the RAC2E protocol with the grid-quorum based channel mapping can yield a powerful RAC2E-gQS rendezvous protocol for asynchronous operation in a distributed environment assuring a rapid rendezvous between the cognitive radio nodes having available both symmetric and asymmetric channel views. We also propose an enhancement of the protocol, which uses a torus QS for a slot allocation, dealing with the worst case scenario, a large number of channels with opposite ranking lists.

EUS-guided biliary drainage by using a standardized approach for malignant biliary obstruction: rendezvous versus direct transluminal techniques (with videos).

Science.gov (United States)

Khashab, Mouen A; Valeshabad, Ali Kord; Modayil, Rani; Widmer, Jessica; Saxena, Payal; Idrees, Mehak; Iqbal, Shahzad; Kalloo, Anthony N; Stavropoulos, Stavros N

2013-11-01

EUS-guided biliary drainage (EGBD) can be performed via direct transluminal or rendezvous techniques. It is unknown how both techniques compare in terms of efficacy and adverse events. To describe outcomes of EGBD performed by using a standardized approach and compare outcomes of rendezvous and transluminal techniques. Retrospective analysis of prospectively collected data. Two tertiary-care centers. Consecutive jaundiced patients with distal malignant biliary obstruction who underwent EGBD after failed ERCP between July 2006 and December 2012 were included. EGBD by using a standardized algorithm. Technical success, clinical success, and adverse events. During the study period, 35 patients underwent EGBD (rendezvous n = 13, transluminal n = 20). Technical success was achieved in 33 patients (94%), and clinical success was attained in 32 of 33 patients (97.0%). The mean postprocedure bilirubin level was 1.38 mg/dL in the rendezvous group and 1.33 mg/dL in the transluminal group (P = .88). Similarly, length of hospital stay was not different between groups (P = .23). There was no significant difference in adverse event rate between rendezvous and transluminal groups (15.4% vs 10%; P = .64). Long-term outcomes were comparable between groups, with 1 stent migration in the rendezvous group at 62 days and 1 stent occlusion in the transluminal group at 42 days after EGBD. Retrospective analysis, small number of patients, and selection bias. EGBD is safe and effective when the described standardized approach is used. Stent occlusion is not common during long-term follow-up. Both rendezvous and direct transluminal techniques seem to be equally effective and safe. The latter approach is a reasonable alternative to rendezvous EGBD. Copyright © 2013. Published by Mosby, Inc.

Analysis for orbital rendezvous of Chang'E-5 using SBI technique

Science.gov (United States)

Huang, Y.; Shan, Q.; Li, P.

2016-12-01

Chang'E-5 will be launched in later 2017/early 2018 using a new generation rocket from Wenchang satellite launch center, Hainan, China. It is a lunar sampling return mission, and it is the first time for China to carry out orbital rendezvous and docking in the Moon. How to achieve orbital rendezvous successfully in the Moon is very important in Chang'E-5 mission. Orbital rendezvous will be implemented between an orbiter and an ascender 200 km above the Moon. The ground tracking techniques include range, Doppler and VLBI, and they will be used to track the orbiter and the ascender when the ascender is about 70 km farther away from the orbiter. Later the ascender will approach the orbiter automatically. As a successful example, in Chang'E-3, the differential phase delay (delta delay) data between the rover and the lander are obtained with a random error of about 1 ps, and the relative position of the rover is determined with an accuracy of several meters by using same beam VLBI (SBI) technique. Here the application of the SBI technique for Chang'E-5 orbital rendezvous is discussed. SBI technique can be used to track the orbiter and the ascender simultaneously when they are in the same beam. Delta delay of the two probes can be derived, and the measurement accuracy is much higher than that of the traditional VLBI data because of the cancelation of common errors. Theoretically it can result in a more accurate relative orbit between the two probes. In the simulation, different strategies are discussed to analyze the contribution of SBI data to the orbit accuracy improvement especially relative orbit between the orbiter and ascender. The simulation results show that the relative position accuracy of the orbiter and ascender can reach about 1 m with delta delay data of 10 ps.

Transmitter-equipped darts in a protocol for chemically immobilizing free-ranging red deer (Cervus elaphus in Central Italy

Directory of Open Access Journals (Sweden)

Sandro Nicoloso

2010-01-01

Full Text Available Twenty-two free-ranging red deer (Cervus elaphus, 9 males and 13 females (7 months to 13 years old, were captured in October-November 2006 and December 2007, along the Apenninic ridge (44°06’N, 11°00’E between the Pistoia (Tuscany and Bologna (Emilia-Romagna provinces, as part of a reintroduction project in Gran Sasso and Laga’s Mountains National Park (42°33’N, 13°28’E, Italy. The aim of the study was to evaluate the effectiveness of a red deer capture protocol, using equipped transmitter darts, in Apennine areas where other methods had not been successful. The red deer were darted (by an operative team of 5-7 operators during dark hours with a mixture of Zoletil® (Z and xylazine (X and, whenever secondary dosages became necessary, a mixture of ketamine (K and X were used. Twenty-five animals were shot, only 3 of which could not be approached to re-dart them. All animals were darted, during dark hours, from a vehicle at a distance of 10-30 m and then recovered, using 3-cc disposable Pneu-dart® transmitter darts, 50-280 m (median 80 m from the dart site. These technical choices were forced by an uneven and wooded environment of the study area. Before the transport to the reintroduction site, the animals were kept in a lairage stable, arranged in single boxes, provided with water and food. This accommodation was necessary to collect a reasonable number of animals to arrange the transport. The immobilized animals were brought to the stable and haemoglobin saturation and heart rate were constantly monitored with a pulse oximeter. Oxygen was insufflated into a nostril at a rate of 10 litres/min for 20-35 min. Atipamezole was administered two thirds intramuscularly (IM and one third intravenously, 45 to 120 min after the last IM narcotic injection, to revive the animals. No side effects other than different levels of meteorism, were displayed. In conclusion, the protocol applied, which proved safe for the animals and had optimal

Orbit Determination for a Microsatellite Rendezvous with a Non-Cooperative Target

National Research Council Canada - National Science Library

Foster, Brian

2003-01-01

This study investigated the minimum requirements to establish a satellite tracking system architecture for a hostile "parasitic microsatellite" to rendezvous with a larger, non-cooperative target satellite...

Cooperative Rendezvous and Docking for Underwater Robots Using Model Predictive Control and Dual Decomposition

DEFF Research Database (Denmark)

Nielsen, Mikkel Cornelius; Johansen, Tor Arne; Blanke, Mogens

2018-01-01

This paper considers the problem of rendezvous and docking with visual constraints in the context of underwater robots with camera-based navigation. The objective is the convergence of the vehicles to a common point while maintaining visual contact. The proposed solution includes the design of a ...... of a distributed model predictive controller based on dual decomposition, which allows for optimization in a decentralized fashion. The proposed distributed controller enables rendezvous and docking between vehicles while maintaining visual contact....

Ternary and hybrid controllers for the rendezvous of unicycles

NARCIS (Netherlands)

Jafarian, Matin

2015-01-01

This paper presents the rendezvous (consensus) of the orientations and average positions of a group of unicycles. We assume that the decentralized controllers designed for consensus of the average positions take only values in the set {-1; 0; +1}. In addition, we introduce a hybrid controller to

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory

Science.gov (United States)

Brewster, L.; Johnston, A.; Howard, R.; Mitchell, J.; Cryan, S.

2007-01-01

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-loop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of"pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Lab

Science.gov (United States)

Brewster, Linda L.; Howard, Richard T.; Johnston, A. S.; Carrington, Connie; Mitchell, Jennifer D.; Cryan, Scott P.

2008-01-01

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success ofthe Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-Ioop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of "pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL

Robust control for spacecraft rendezvous system with actuator unsymmetrical saturation: a gain scheduling approach

Science.gov (United States)

Wang, Qian; Xue, Anke

2018-06-01

This paper has proposed a robust control for the spacecraft rendezvous system by considering the parameter uncertainties and actuator unsymmetrical saturation based on the discrete gain scheduling approach. By changing of variables, we transform the actuator unsymmetrical saturation control problem into a symmetrical one. The main advantage of the proposed method is improving the dynamic performance of the closed-loop system with a region of attraction as large as possible. By the Lyapunov approach and the scheduling technology, the existence conditions for the admissible controller are formulated in the form of linear matrix inequalities. The numerical simulation illustrates the effectiveness of the proposed method.

Kinesthetic motor imagery training modulates frontal midline theta during imagination of a dart throw.

Science.gov (United States)

Weber, E; Doppelmayr, M

2016-12-01

Motor imagery (MI) is a frequently used and effective method for motor learning in sports as well as in other domains. Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) studies indicated that experts within a certain sport exhibit a more pronounced brain activity during MI as compared to novices. Similar to the execution, during MI the motor sequence has to be planned. Thus, the frontal attentional system, in part represented by the frontal midline theta (4-7Hz), is closely related to these processes and presumably plays a major role in MI as well. In this study, a MI dart training and its impact on frontal midline theta activity (fmt) during MI are examined. 53 healthy subjects with no prior dart experience were randomly allocated to a kinesthetic training group (KinVis) or to a control group (Control). Both groups performed 15 training sessions. While in the KinVis group dart throwing was accompanied by MI, the Control group trained without MI. Dart performance and fmt activity during MI within the first and the 15th session were compared. As expected, the performance increase was more pronounced in the KinVis group. Furthermore, frontal theta amplitude was significantly increased in the KinVis group during MI in the 15th training session as compared to the baseline. These results confirm the effectivity of MI. The enhanced fmt activity in the KinVis group can be interpreted as a better allocation of the requested resources in the frontal attentional network after MI. Copyright © 2016 Elsevier B.V. All rights reserved.

Genetic linkage mapping in an F2 perennial ryegrass population using DArT markers

DEFF Research Database (Denmark)

Tomaszewski, Céline; Byrne, Stephen; Foito, Alexandra

2012-01-01

Perennial ryegrass is the principal forage grass species used in temperate agriculture. In recent years, significant efforts have been made to develop molecular marker strategies to allow cost-effective characterization of a large number of loci simultaneously. One such strategy involves using DAr......T markers, and a DArT array has recently been developed for the Lolium-Festuca complex. In this study, we report the first use of the DArTFest array to generate a genetic linkage map based on 326 markers in a Lolium perenne F2 population, consisting of 325 genotypes. For proof of concept, the map was used...

Percutaneous-endoscopic rendezvous procedure for the management of bile duct injuries after cholecystectomy: short- and long-term outcomes

NARCIS (Netherlands)

Schreuder, Anne Marthe; Booij, Klaske A. C.; de Reuver, Philip R.; van Delden, Otto M.; van Lienden, Krijn P.; Besselink, Marc G.; Busch, Olivier R.; Gouma, Dirk J.; Rauws, Erik A. J.; van Gulik, Thomas M.

2018-01-01

Bile duct injury (BDI) remains a daunting complication of laparoscopic cholecystectomy. In patients with complex BDI, a percutaneous-endoscopic rendezvous procedure may be required to establish bile duct continuity. The aim of this study was to assess short- and long-term outcomes of the rendezvous

The comet rendezvous asteroid flyby mission

International Nuclear Information System (INIS)

Morrison, D.; Neugebauer, M.; Weissman, P.R.

1989-01-01

The Comet Rendezvous Asteroid Flyby (CRAF) mission is designed to answer the many questions raised by the Halley missions by exploring a cometary nucleus in detail, following it around its orbit and studying its changing activity as it moves closer to and then away from the Sun. In addition, on its way to rendezvous with the comet, CRAF will fly by a large, primitive class main belt asteroid and will return valuable data for comparison with the comet results. The selected asteroid is 449 Hamburga with a diameter of 88 km and a surface composition of carbonaceous chondrite meteorites. The expected flyby date is January, 1998. The CRAF spacecraft will continue to make measurements in orbit around the cometary nucleus as they both move closer to the Sun, until the dust and gas hazard becomes unsafe. At that point the spacecraft will move in and out between 50 and 2,500 kilometers to study the inner coma and the cometary ionosphere, and to collect dust and gas samples for onboard analysis. Following perihelion, the spacecraft will make a 50,000 km excursion down the comet's tail, further investigating the solar wind interaction with the cometary atmosphere. The spacecraft will return to the vicinity of the nucleus about four months after perihelion to observe the changes that have taken place. If the spacecraft remains healthy and adequate fuel is still onboard, an extended mission to follow the comet nucleus out to aphelion is anticipated

Dalla parola all'immagine: il linguaggio della critica d'arte: Per la traduzione di una "traduzione"

OpenAIRE

De Martin, Maria Pia

1994-01-01

Negli ultimi decenni i musei e le gallerie d'arte di tutta Europa hanno visto crescere continuamente l'afflusso dei visitatori: basti pensare alle grandi mostre degli ultimi anni e alle interminabili code per accedervi (per esempio Kandinsky a Parigi e a Milano nel 1985). Laddove, in passato, la fruizione delle opere d'arte era limitata ad una stretta cerchia di persone, esse sembrano aver risvegliato oggi l'interesse del grande pubblico. Insieme all'interesse generale cres...

Endoskopisk ultralydvejledt rendezvous til intern drænage ved galdevejsobstruktion

DEFF Research Database (Denmark)

Knudsen, Marie Høxbro; Vilmann, Peter; Hassan, Hazem

2015-01-01

Endoscopic retrograde cholangiography (ERCP) is currently standard treatment for biliary drainage. Endoscopic ultrasound guided rendezvous (EUS-RV) is a novel method to overcome an unsuccessful biliary drainage procedure. Under endoscopic ultrasound guidance a guidewire is passed via a needle from...

[Ureteral realignment with the rendezvous procedure in complex ureteral injuries - aspects of technique and our experience].

Science.gov (United States)

Brandt, Alexander Sascha; von Rundstedt, F-C; Lazica, D A; Roth, S

2010-07-01

The rendezvous procedure for re-establishing ureteral continuity after complex ureteral injuries is introduced and we present our experience with this technique. Aspects of the technique are described in a detailed step-by-step instruction using intraoperative radiographs. We evaluated our patient data from 1998 until 2009 for cases in which the rendezvous procedure was attempted. The rendezvous procedure was used in a total of 11 patients. Realignment was successful in 10 cases (90.9 %) and the initial nephrostomy could be removed. In 3 of 7 cases postoperative removal of the JJ ureteric stent was successful. In 7 patients the final surgical ureter reconstruction was performed after a medium period of 7 months. 5 cases of ureteroneocystostomy and 2 cases of reconstruction of the ureter either with colon or ileum segments were accomplished. In 1 patient a permanent maintenance of the DJ ureteral stent was necessary. Ureteral realignment with the rendezvous procedure enables disposition of the ureteral stent in many cases, exclusively antegrade or retrograde procedures failed. By this means nephrostomy could be spared as a temporary or permanent solution and a better chance of restitutio ad integrum could be realised. Georg Thieme Verlag KG Stuttgart * New York.

Optimal planning approaches with multiple impulses for rendezvous based on hybrid genetic algorithm and control method

Directory of Open Access Journals (Sweden)

JingRui Zhang

2015-03-01

Full Text Available In this article, we focus on safe and effective completion of a rendezvous and docking task by looking at planning approaches and control with fuel-optimal rendezvous for a target spacecraft running on a near-circular reference orbit. A variety of existent practical path constraints are considered, including the constraints of field of view, impulses, and passive safety. A rendezvous approach is calculated by using a hybrid genetic algorithm with those constraints. Furthermore, a control method of trajectory tracking is adopted to overcome the external disturbances. Based on Clohessy–Wiltshire equations, we first construct the mathematical model of optimal planning approaches of multiple impulses with path constraints. Second, we introduce the principle of hybrid genetic algorithm with both stronger global searching ability and local searching ability. We additionally explain the application of this algorithm in the problem of trajectory planning. Then, we give three-impulse simulation examples to acquire an optimal rendezvous trajectory with the path constraints presented in this article. The effectiveness and applicability of the tracking control method are verified with the optimal trajectory above as control objective through the numerical simulation.

Rendezvous technique for recanalization of long-segmental chronic total occlusion above the knee following unsuccessful standard angioplasty.

Science.gov (United States)

Cao, Jun; Lu, Hai-Tao; Wei, Li-Ming; Zhao, Jun-Gong; Zhu, Yue-Qi

2016-04-01

To assess the technical feasibility and efficacy of the rendezvous technique, a type of subintimal retrograde wiring, for the treatment of long-segmental chronic total occlusions above the knee following unsuccessful standard angioplasty. The rendezvous technique was attempted in eight limbs of eight patients with chronic total occlusions above the knee after standard angioplasty failed. The clinical symptoms and ankle-brachial index were compared before and after the procedure. At follow-up, pain relief, wound healing, limb salvage, and the presence of restenosis of the target vessels were evaluated. The rendezvous technique was performed successfully in seven patients (87.5%) and failed in one patient (12.5%). Foot pain improved in all seven patients who underwent successful treatment, with ankle-brachial indexes improving from 0.23 ± 0.13 before to 0.71 ± 0.09 after the procedure (P rendezvous technique is a feasible and effective treatment for chronic total occlusions above the knee when standard angioplasty fails. © The Author(s) 2015.

A "rendezvous technique" for treating a pancreatic fistula after distal pancreatectomy.

Science.gov (United States)

Imai, Daisuke; Yamashita, Yo-ichi; Ikegami, Toru; Toshima, Takeo; Harimoto, Norifumi; Yoshizumi, Tomoharu; Soejima, Yuji; Shirabe, Ken; Ikeda, Tetsuo; Maehara, Yoshihiko

2015-01-01

Pancreatic fistulae are a major complication of distal pancreatectomy (DP). Some cases of severe pancreatic fistula require invasive procedures. There have been some reports concerning the effectiveness of pancreatic duct drainage through an endoscopic transpapillary approach for pancreatic fistulae. We herein present a case of a pancreatic fistula after DP that was successfully treated with percutaneous pancreatic duct drainage, which was performed using a combined percutaneous and endoscopic approach, named the "rendezvous technique". In our case, we performed distal pancreatectomy with celiac artery resection for a locally advanced pancreatic body cancer. On postoperative day (POD) 7, the drain amylase level increased up to 37,460 IU/l. Computed tomography (CT) revealed peripancreatic fluid collections. On POD 10, we placed a catheter in the main pancreatic duct using the rendezvous technique. CT on POD 14 revealed a decrease in the size of the peripancreatic fluid collection, and contrast imaging from the drains on POD 22 revealed almost complete disappearance of the fluid collection. We withdrew the pigtail catheter on POD 27 and the percutaneous pancreatic duct drain on POD 36. This patient was discharged from our hospital on POD 40. We herein report a new approach called the "rendezvous technique" for the management of pancreatic fistulae after DP that can be used instead of a stressful nasopancreatic tube.

"Rendezvous technique" for intraluminal vacuum therapy of anastomotic leakage of the jejunum.

Science.gov (United States)

Krajinovic, K; Reimer, S; Kudlich, T; Germer, C T; Wiegering, A

2016-12-01

Anastomotic leakage (AL) is one of the most common and serious complications following visceral surgery. In recent years, endoluminal vacuum therapy has dramatically changed therapeutic options for AL, but its use has been limited to areas easily accessible by endoscope. We describe the first use of endoluminal vacuum therapy in the small intestine employing a combined surgical and endoscopic "rendezvous technique" in which the surgeon assists the endoscopic placement of an endoluminal vacuum therapy sponge in the jejunum by means of a pullback string. This technique led to a completely closed AL after 27 days and 7 changes of the endosponge. The combined surgical and endoscopic rendezvous technique can be useful in cases of otherwise difficult endosponge placement.

Choledocholithiasis and endo-laparoscopic rendezvous. Analysis of 59 consecutive cases.

Science.gov (United States)

Del Rio, Paolo; Dell'Abate, Paolo; Labonia, Domenico; Negri, Marco; Sianesi, Nicoletta; Arcuri, Maria Francesca; Sianesi, Mario

2011-01-01

Choledocholithiasis is a real problem of major clinical importance. The incidence of cholelithiasis is 10-20%. We have examined 2907 patients treated with videolaparoscopic cholecystectomy (VLC) between January 2001 and September 2009. 214 cases (7.4%) were affected by choledocolithiasis; among these, 59 consecutive cases were treated by rendezvous, 151 cases by sequential treatment (ERCP-ES before VLC), 3 cases by extraction with Dormia's basket, and 1 case by ERCP-ES after VLC. The complications were one biliary fistula and three hemorrhages (one from the cystic artery, one from the hepatic area and one from trocar's site). The mean hospital stay was 1.38 +/- 0.83 days for the rendezvous group vs 4 53 +/- 0.74 days in the sequential treatment group (prendezvous procedure reduces hospital stay and has a greater compliance (only one treatment). We can use this option in the management of cases where preoperative ERCP-ES has failed.

[Endoscopic ultrasound guided rendezvous for biliary drainage].

Science.gov (United States)

Knudsen, Marie Høxbro; Vilmann, Peter; Hassan, Hazem; Karstensen, John Gésdal

2015-04-27

Endoscopic retrograde cholangiography (ERCP) is currently standard treatment for biliary drainage. Endoscopic ultrasound guided rendezvous (EUS-RV) is a novel method to overcome an unsuccessful biliary drainage procedure. Under endoscopic ultrasound guidance a guidewire is passed via a needle from the stomach or duodenum to the common bile duct and from there on to the duodenum enabling ERCP. With a relatively high rate of success EUS-RV should be considered as an alternative to biliary drainage and surgical intervention.

The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections

International Nuclear Information System (INIS)

Chen, Delei; Goris, Bart; Bleichrodt, Folkert; Mezerji, Hamed Heidari; Bals, Sara; Batenburg, Kees Joost; With, Gijsbertus de; Friedrich, Heiner

2014-01-01

In electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and applying different angular sampling schemes. A well-defined realistic model is generated, which consists of tubular domains within a matrix having slab-geometry. Subsequently, the electron tomography workflow is simulated from calculated tilt-series over experimental effects to reconstruction. In comparison with the model, the fidelity of each reconstruction method is evaluated qualitatively and quantitatively based on global and local edge profiles and resolvable distance between particles. Results show that the performance of all reconstruction methods declines with the total electron dose. Overall, SIRT algorithm is the most stable method and insensitive to changes in angular sampling. TVM algorithm yields significantly sharper edges in the reconstruction, but the edge positions are strongly influenced by the tilt scheme and the tubular objects become thinned. The DART algorithm markedly suppresses the elongation artifacts along the beam direction and moreover segments the reconstruction which can be considered a significant advantage for quantification. Finally, no advantage of TVM and DART to deal better with fewer projections was observed. - Highlights: • Dose and tilt-scheme dependence of SIRT, TVM and DART tomograms are quantified. • SIRT is the most stable method and insensitive to changes in angular sampling. • TVM significantly reduces noise but objects become thinned. • DART markedly suppresses the elongation artifacts. • No advantage of TVM and DART for fewer projections is observed

The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections

Energy Technology Data Exchange (ETDEWEB)

Chen, Delei [Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven (Netherlands); Goris, Bart [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Bleichrodt, Folkert [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); Mezerji, Hamed Heidari; Bals, Sara [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Batenburg, Kees Joost [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); With, Gijsbertus de [Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); Friedrich, Heiner, E-mail: h.friedrich@tue.nl [Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands)

2014-12-15

In electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and applying different angular sampling schemes. A well-defined realistic model is generated, which consists of tubular domains within a matrix having slab-geometry. Subsequently, the electron tomography workflow is simulated from calculated tilt-series over experimental effects to reconstruction. In comparison with the model, the fidelity of each reconstruction method is evaluated qualitatively and quantitatively based on global and local edge profiles and resolvable distance between particles. Results show that the performance of all reconstruction methods declines with the total electron dose. Overall, SIRT algorithm is the most stable method and insensitive to changes in angular sampling. TVM algorithm yields significantly sharper edges in the reconstruction, but the edge positions are strongly influenced by the tilt scheme and the tubular objects become thinned. The DART algorithm markedly suppresses the elongation artifacts along the beam direction and moreover segments the reconstruction which can be considered a significant advantage for quantification. Finally, no advantage of TVM and DART to deal better with fewer projections was observed. - Highlights: • Dose and tilt-scheme dependence of SIRT, TVM and DART tomograms are quantified. • SIRT is the most stable method and insensitive to changes in angular sampling. • TVM significantly reduces noise but objects become thinned. • DART markedly suppresses the elongation artifacts. • No advantage of TVM and DART for fewer projections is observed.

Orion Handling Qualities During ISS Rendezvous and Docking

Science.gov (United States)

Hart, Jeremy J.; Stephens, J. P.; Spehar, P.; Bilimoria, K.; Foster, C.; Gonzalex, R.; Sullivan, K.; Jackson, B.; Brazzel, J.; Hart, J.

2011-01-01

The Orion spacecraft was designed to rendezvous with multiple vehicles in low earth orbit (LEO) and beyond. To perform the required rendezvous and docking task, Orion must provide enough control authority to perform coarse translational maneuvers while maintaining precision to perform the delicate docking corrections. While Orion has autonomous docking capabilities, it is expected that final approach and docking operations with the International Space Station (ISS) will initially be performed in a manual mode. A series of evaluations was conducted by NASA and Lockheed Martin at the Johnson Space Center to determine the handling qualities (HQ) of the Orion spacecraft during different docking and rendezvous conditions using the Cooper-Harper scale. This paper will address the specifics of the handling qualities methodology, vehicle configuration, scenarios flown, data collection tools, and subject ratings and comments. The initial Orion HQ assessment examined Orion docking to the ISS. This scenario demonstrates the Translational Hand Controller (THC) handling qualities of Orion. During this initial assessment, two different scenarios were evaluated. The first was a nominal docking approach to a stable ISS, with Orion initializing with relative position dispersions and a closing rate of approximately 0.1 ft/sec. The second docking scenario was identical to the first, except the attitude motion of the ISS was modeled to simulate a stress case ( 1 degree deadband per axis and 0.01 deg/sec rate deadband per axis). For both scenarios, subjects started each run on final approach at a docking port-to-port range of 20 ft. Subjects used the THC in pulse mode with cues from the docking camera image, window views, and range and range rate data displayed on the Orion display units. As in the actual design, the attitude of the Orion vehicle was held by the automated flight control system at 0.5 degree deadband per axis. Several error sources were modeled including Reaction

Autonomous Mars ascent and orbit rendezvous for earth return missions

Science.gov (United States)

Edwards, H. C.; Balmanno, W. F.; Cruz, Manuel I.; Ilgen, Marc R.

1991-01-01

The details of tha assessment of autonomous Mars ascent and orbit rendezvous for earth return missions are presented. Analyses addressing navigation system assessments, trajectory planning, targeting approaches, flight control guidance strategies, and performance sensitivities are included. Tradeoffs in the analysis and design process are discussed.

77 FR 47120 - Distribution of 2011 DART Sound Recordings Fund Royalties

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2012-08-07

... the motion to ascertain whether any claimant entitled to receive such royalty fees has a reasonable... LIBRARY OF CONGRESS Copyright Royalty Board [Docket No. 2012-3 CRB DD 2011] Distribution of 2011 DART Sound Recordings Fund Royalties AGENCY: Copyright Royalty Board, Library of Congress. ACTION...

Stricture location predicts swallowing outcomes following endoscopic rendezvous procedures.

Science.gov (United States)

Adams, Katherine N; Shah, Rupali N; Buckmire, Robert A

2017-06-01

Complete pharyngoesophageal strictures may be encountered by the otolaryngologist as a consequence of radiation/chemoradiotherapy therapies for head and neck cancer. A combined anterograde and retrograde dilation procedure (rendezvous procedure) has proven to be a useful surgical intervention in these cases. We assess the long-term swallowing outcomes of this patient cohort including gastrostomy tube (G-tube) reliance, swallowing quality of life, and variables that contribute to improved swallowing outcomes. Retrospective chart review. A retrospective chart review of 18 consecutive patients treated with rendezvous procedures between April 2007 and May 2015 was carried out. Data were collected from chart review and follow-up telephone calls including demographics, surgical/postoperative course details, and Eating Assessment Tool (EAT-10) (swallowing quality of life) scores. The completion rate of the procedure was 83% (15 completed/3 procedures aborted). Average follow-up was 22 months. Thirteen of 15 (86.7%) achieved an oral diet, and 7/15 (46.7%) had their G-tube removed. G-tube-independent (GTI) patients had an average stricture length of 2.33 cm and an average distance from the incisors of 17.4 cm compared to G-tube dependent-(GTD) patients who had an average stricture length of 2.63 cm and 14.6 cm mean distance from the incisors (P = .66 and .0343, respectively). Final EAT-10 scores averaged 20.1 in GTI patients and 33.8 in GTD patients (P = .022). Stricture/incisor distance and EAT-10 scores demonstrated a moderate to strong negative correlation (r = -0.67). Following the endoscopic rendezvous procedure, swallowing outcomes and G-tube status is related to the distance of the stricture from the incisors. 2b Laryngoscope, 127:1388-1391, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

A Ground Testbed to Advance US Capability in Autonomous Rendezvous and Docking Project

Science.gov (United States)

D'Souza, Chris

2014-01-01

This project will advance the Autonomous Rendezvous and Docking (AR&D) GNC system by testing it on hardware, particularly in a flight processor, with a goal of testing it in IPAS with the Waypoint L2 AR&D scenario. The entire Agency supports development of a Commodity for Autonomous Rendezvous and Docking (CARD) as outlined in the Agency-wide Community of Practice whitepaper entitled: "A Strategy for the U.S. to Develop and Maintain a Mainstream Capability for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond". The whitepaper establishes that 1) the US is in a continual state of AR&D point-designs and therefore there is no US "off-the-shelf" AR&D capability in existence today, 2) the US has fallen behind our foreign counterparts particularly in the autonomy of AR&D systems, 3) development of an AR&D commodity is a national need that would benefit NASA, our commercial partners, and DoD, and 4) an initial estimate indicates that the development of a standardized AR&D capability could save the US approximately $60M for each AR&D project and cut each project's AR&D flight system implementation time in half.

DART - for design basis justification and safety related information management

International Nuclear Information System (INIS)

Billington, A.; Blondiaux, P.; Boucau, J.; Cantineau, B.; Doumont, C.; Mared, A.

2000-01-01

DART is the acronym for Design Analysis Re-engineering Tool. It embodies a systematic and integrated approach to NPP safety re-assessment and configuration management, that makes use of Reverse Failure Mode and Effect Analysis in conjunction with a state-of-the-art relational database and a standardized data format, to permit long-term management of plant safety related information. The plant design is reviewed in a step-by-step logical fashion by constructing fault trees that identify the link between undesired consequences and their causes. Each failure cause identified in a fault tree is addressed by defining functional requirements, which are in turn addressed by documenting the specific manner in which the plant complies with the requirement. The database can be used to generate up-to-date plant safety related documents, including: SAR, Systems Descriptions, Technical Specifications and plant procedures. The approach is open-minded by nature and therefore is not regulatory driven, however the plant licensing basis will also be reviewed and documented within the same database such that a Regulatory Conformance Program may be integrated with the other safety documentation. This methodology can thus reconstitute the plant design bases in a comprehensive and systematic way, while allowing to uncover weaknesses in design. The original feature of the DART methodology is that it links all the safety related documents together, facilitating the evaluation of the safety impact resulting from any plant modification. Due to its capability to retrieve the basic justifications of the plant design, it is also a useful tool for training the young generation of plant personnel. The DART methodology has been developed for application to units 2, 3 and 4 at Vattenfall's Ringhals site in Sweden. It may be applied to any nuclear power plant or industrial facility where public safety is a concern. (author)

DART - for design basis justification and safety related information management

International Nuclear Information System (INIS)

Billington, A.; Blondiaux, B.; Boucau, J.; Cantineau, B.; Mared, A.

2001-01-01

DART is the acronym for Design Analysis Re-Engineering Tool. It embodies a systematic and integrated approach to NPP safety re-assessment and configuration management, that makes use of Reverse Failure Mode and Effect Analysis in conjunction with a state-of-the-art relational database and a standardized data format, to permit long-term management of plant safety related information. The plant design is reviewed in a step-by-step logical fashion by constructing fault trees that identify the link between undesired consequences and their causes. Each failure cause identified in a fault tree is addressed by defining functional requirements, which are in turn addressed by documenting the specific manner in which the plant complies with the requirement. The database can then be used to generate up-to-date plant safety related documents, including: SAR, Systems Descriptions, Technical Specifications and plant procedures. The approach is open-minded by nature and therefore is not regulatory driven, however the plant licensing basis will also be reviewed and documented within the same database such that a Regulatory Conformance Program may be integrated with the other safety documentation. This methodology can thus reconstitute the plant design bases in a comprehensive and systematic way, while allowing to uncover weaknesses in design. The original feature of the DART methodology is that it links all the safety related documents together, facilitating the evaluation of the safety impact resulting from any plant modification. Due to its capability to retrieve the basic justifications of the plant design, it is also a useful tool for training the young generation of plant personnel. The DART methodology has been developed for application to units 2, 3 and 4 at Vattenfall's Ringhals site in Sweden. It may be applied to any nuclear power plant or industrial facility where public safety is a concern. (author)

Concurrent image-based visual servoing with adaptive zooming for non-cooperative rendezvous maneuvers

Science.gov (United States)

Pomares, Jorge; Felicetti, Leonard; Pérez, Javier; Emami, M. Reza

2018-02-01

An image-based servo controller for the guidance of a spacecraft during non-cooperative rendezvous is presented in this paper. The controller directly utilizes the visual features from image frames of a target spacecraft for computing both attitude and orbital maneuvers concurrently. The utilization of adaptive optics, such as zooming cameras, is also addressed through developing an invariant-image servo controller. The controller allows for performing rendezvous maneuvers independently from the adjustments of the camera focal length, improving the performance and versatility of maneuvers. The stability of the proposed control scheme is proven analytically in the invariant space, and its viability is explored through numerical simulations.

76 FR 56483 - Distribution of 2010 DART Sound Recordings Fund Royalties

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2011-09-13

... responses to the motion to ascertain whether any claimant entitled to receive such royalty fees has a... LIBRARY OF CONGRESS Copyright Royalty Board [Docket No. 2011-6 CRB DD 2010] Distribution of 2010 DART Sound Recordings Fund Royalties AGENCY: Copyright Royalty Board, Library of Congress. ACTION...

Rendezvous and docking tracker

Science.gov (United States)

Ray, Art J.; Ross, Susan E.; Deming, Douglas R.

1986-01-01

A conceptual solid-state rendezvous and docking tracker (RDT) has been devised for generating range and attitude data for a docking vehicle relative to a target vehicle. Emphasis is placed on the approach of the Orbiter to a link with the Space Station. Three laser illuminators ring the optical axis of the lens a directed toward retroreflectors on the target vehicle. Each retroreflector is equipped with a bandpass filter for a designated illumination frequency. Data are collected sequentially over a 20 deg field of view as the range closes to 100-1000 m. A fourth ranging retroreflector 0.3 m from center is employed during close-in maneuvers. The system provides tracking data on motions with 6 deg of freedom, and furnishes 500 msec updates (to be enhanced to 100 msec) to the operator at a computer console.

Modular, Reconfigurable, High-Energy Technology Development

Science.gov (United States)

Carrington, Connie; Howell, Joe

2006-01-01

The Modular, Reconfigurable High-Energy (MRHE) Technology Demonstrator project was to have been a series of ground-based demonstrations to mature critical technologies needed for in-space assembly of a highpower high-voltage modular spacecraft in low Earth orbit, enabling the development of future modular solar-powered exploration cargo-transport vehicles and infrastructure. MRHE was a project in the High Energy Space Systems (HESS) Program, within NASA's Exploration Systems Research and Technology (ESR&T) Program. NASA participants included Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), and Glenn Research Center (GRC). Contractor participants were the Boeing Phantom Works in Huntsville, AL, Lockheed Martin Advanced Technology Center in Palo Alto, CA, ENTECH, Inc. in Keller, TX, and the University of AL Huntsville (UAH). MRHE's technical objectives were to mature: (a) lightweight, efficient, high-voltage, radiation-resistant solar power generation (SPG) technologies; (b) innovative, lightweight, efficient thermal management systems; (c) efficient, 100kW-class, high-voltage power delivery systems from an SPG to an electric thruster system; (d) autonomous rendezvous and docking technology for in-space assembly of modular, reconfigurable spacecraft; (e) robotic assembly of modular space systems; and (f) modular, reconfigurable distributed avionics technologies. Maturation of these technologies was to be implemented through a series of increasingly-inclusive laboratory demonstrations that would have integrated and demonstrated two systems-of-systems: (a) the autonomous rendezvous and docking of modular spacecraft with deployable structures, robotic assembly, reconfiguration both during assembly and (b) the development and integration of an advanced thermal heat pipe and a high-voltage power delivery system with a representative lightweight high-voltage SPG array. In addition, an integrated simulation testbed would have been developed

The history and composition of the Raymond A. Dart Collection of Human Skeletons at the University of the Witwatersrand, Johannesburg, South Africa.

Science.gov (United States)

Dayal, Manisha R; Kegley, Anthony D T; Strkalj, Goran; Bidmos, Mubarak A; Kuykendall, Kevin L

2009-10-01

The Raymond A. Dart Collection of Human Skeletons (Dart Collection) is housed in the School of Anatomical Sciences at the University of the Witwatersrand, Johannesburg, South Africa, and comprises one of the largest documented cadaver-derived human skeletal assemblages in the world. This collection originated in the early 1920s as a result of the efforts of Raymond Dart and continues to grow. The skeletons included represent varied indigenous and immigrant populations from southern Africa, Europe and Asia. This contribution documents the history of the collection and provides an updated inventory and demographic assessment of this valuable research collection. According to a recent inventory the Dart Collection currently comprises 2,605 skeletons representing individuals from regional SA African (76%), White (15%), Coloured (4%) and Indian (0.3%) populations. A large proportion of the skeletons (71%) represent males. The recorded ages at death range from the first year to over 100 years of age, but the majority of individuals died between the ages of 20 and 70. The Dart Collection has been affected by collection procedures based on availability. All of the cadavers collected before 1958, and large proportions subsequently, were derived from unclaimed bodies in regional South African hospitals. Some details of documentation (age at death, population group) are estimates and some aspects of the collection demographics (sex ratios) do not closely reflect any living South African population. Our inventory and analysis of the Dart Collection is aimed to assist researchers planning research on the materials from this collection.

Constraints on the perturbed mutual motion in Didymos due to impact-induced deformation of its primary after the DART impact

Science.gov (United States)

Hirabayashi, Masatoshi; Schwartz, Stephen R.; Yu, Yang; Davis, Alex B.; Chesley, Steven R.; Fahnestock, Eugene G.; Michel, Patrick; Richardson, Derek C.; Naidu, Shantanu P.; Scheeres, Daniel J.; Cheng, Andrew F.; Rivkin, Andrew S.; Benner, Lance A. M.

2017-12-01

Binary near-Earth asteroid (65803) Didymos is the target of the proposed NASA Double Asteroid Redirection Test (DART), part of the Asteroid Impact & Deflection Assessment (AIDA) mission concept. In this mission, the DART spacecraft is planned to impact the secondary body of Didymos, perturbing mutual dynamics of the system. The primary body is currently rotating at a spin period close to the spin barrier of asteroids, and materials ejected from the secondary due to the DART impact are likely to reach the primary. These conditions may cause the primary to reshape, due to landslides or internal deformation, changing the permanent gravity field. Here, we propose that if shape deformation of the primary occurs, the mutual orbit of the system would be perturbed due to a change in the gravity field. We use a numerical simulation technique based on the full two-body problem to investigate the shape effect on the mutual dynamics in Didymos after the DART impact. The results show that under constant volume, shape deformation induces strong perturbation in the mutual motion. We find that the deformation process always causes the orbital period of the system to become shorter. If surface layers with a thickness greater than ∼0.4 m on the poles of the primary move down to the equatorial region due to the DART impact, a change in the orbital period of the system and in the spin period of the primary will be detected by ground-based measurement.

Guidance and Control of Position and Attitude for Rendezvous and Dock/Berthing with a Noncooperative/Target Spacecraft

Directory of Open Access Journals (Sweden)

Gilberto Arantes

2014-01-01

Full Text Available Noncooperative target spacecrafts are those assets in orbit that cannot convey any information about their states (position, attitude, and velocities or facilitate rendezvous and docking/berthing (RVD/B process. Designing a guidance, navigation, and control (GNC module for the chaser in a RVD/B mission with noncooperative target should be inevitably solved for on-orbit servicing technologies. The proximity operations and the guidance for achieving rendezvous problems are addressed in this paper. The out-of-plane maneuvers of proximity operations are explored with distinct subphases, including a chaser far approach in the target’s orbit to the first hold point and a closer approach to the final berthing location. Accordingly, guidance solutions are chosen for each subphase from the standard Hill based Closhessy-Willtshire (CW solution, elliptical fly-around, and Glideslope algorithms. The control is based on a linear quadratic regulator approach (LQR. At the final berthing location, attitude tracker based on a proportional derivative (PD form is tested to synchronize the chaser and target attitudes. The paper analyzes the performance of both controllers in terms of the tracking ability and the robustness. Finally, it prescribes any restrictions that may be imposed on the guidance during any subphase which can help to improve the controllers tracking ability.

Endoscopic rendezvous procedure for ureteral iatrogenic detachment: report of a case series with long-term outcomes.

Science.gov (United States)

Pastore, Antonio Luigi; Palleschi, Giovanni; Silvestri, Luigi; Leto, Antonino; Autieri, Domenico; Ripoli, Andrea; Maggioni, Cristina; Al Salhi, Yazan; Carbone, Antonio

2015-04-01

Injury to the ureter is the most common urologic complication of pelvic surgery, with an incidence that ranges from 1% to 10%. Most cases of ureteral injuries are related to gynecologic procedures. The ureter is particularly vulnerable to detachment or ligation during hysterectomy because of its position from the lateral edge of the cervix. We report a case series of female patients who underwent the ureteral rendezvous procedure for ureteral detachment. Between January 2009 and April 2013, 18 ureteral rendezvous procedures were performed for patients with complete detachment. We assessed the operative and clinical outcomes of these patients over a mean follow-up duration of 26.5 months and describe the three most representative cases. The endoscopic rendezvous technique was performed in all cases to manage ureteral detachment. CT urography at discharge and 6 and 12 months after discharge confirmed the restoration of ureteral integrity without any leakage in 66% (12/18) patients, indicated ureteral stenosis in 22% (4/18) patients, and indicated ureteral leakage in 12% (2/18) patients. The overall long-term success rate for all 18 patients was 78% (14/18) at a mean follow-up of 26.5 months. The endoscopic rendezvous procedure reduces the need for invasive open surgical repair and represents the optimal initial option in patients with iatrogenic ureteral lesions before invasive procedures with higher morbidity are attempted.

Rendezvous missions with minimoons from L1

Science.gov (United States)

Chyba, M.; Haberkorn, T.; Patterson, G.

2014-07-01

We propose to present asteroid capture missions with the so-called minimoons. Minimoons are small asteroids that are temporarily captured objects on orbits in the Earth-Moon system. It has been suggested that, despite their small capture probability, at any time there are one or two meter diameter minimoons, and progressively greater numbers at smaller diameters. The minimoons orbits differ significantly from elliptical orbits which renders a rendezvous mission more challenging, however they offer many advantages for such missions that overcome this fact. First, they are already on geocentric orbits which results in short duration missions with low Delta-v, this translates in cost efficiency and low-risk targets. Second, beside their close proximity to Earth, an advantage is their small size since it provides us with the luxury to retrieve the entire asteroid and not only a sample of material. Accessing the interior structure of a near-Earth satellite in its morphological context is crucial to an in-depth analysis of the structure of the asteroid. Historically, 2006 RH120 is the only minimoon that has been detected but work is ongoing to determine which modifications to current observation facilities is necessary to provide detection algorithm capabilities. In the event that detection is successful, an efficient algorithm to produce a space mission to rendezvous with the detected minimoon is highly desirable to take advantage of this opportunity. This is the main focus of our work. For the design of the mission we propose the following. The spacecraft is first placed in hibernation on a Lissajoux orbit around the liberation point L1 of the Earth-Moon system. We focus on eight-shaped Lissajoux orbits to take advantage of the stability properties of their invariant manifolds for our transfers since the cost to minimize is the spacecraft fuel consumption. Once a minimoon has been detected we must choose a point on its orbit to rendezvous (in position and velocities

Detection of caffeine in tea, instant coffee, green tea beverage, and soft drink by direct analysis in real time (DART) source coupled to single-quadrupole mass spectrometry.

Science.gov (United States)

Wang, Lei; Zhao, Pengyue; Zhang, Fengzu; Bai, Aijuan; Pan, Canping

2013-01-01

Ambient ionization direct analysis in real time (DART) coupled to single-quadrupole MS (DART-MS) was evaluated for rapid detection of caffeine in commercial samples without chromatographic separation or sample preparation. Four commercial samples were examined: tea, instant coffee, green tea beverage, and soft drink. The response-related parameters were optimized for the DART temperature and MS fragmentor. Under optimal conditions, the molecular ion (M+H)+ was the major ion for identification of caffeine. The results showed that DART-MS is a promising tool for the quick analysis of important marker molecules in commercial samples. Furthermore, this system has demonstrated significant potential for high sample throughput and real-time analysis.

Resolving external pancreatic fistulas in patients with disconnected pancreatic duct syndrome: using rendezvous techniques to avoid surgery (with video).

Science.gov (United States)

Irani, Shayan; Gluck, Michael; Ross, Andrew; Gan, S Ian; Crane, Robert; Brandabur, John J; Hauptmann, Ellen; Fotoohi, Mehran; Kozarek, Richard A

2012-09-01

An external pancreatic fistula (EPF) generally results from an iatrogenic manipulation of a pancreatic fluid collection (PFC), such as walled-off pancreatic necrosis (WOPN). Severe necrotizing pancreatitis can lead to complete duct disruption, causing disconnected pancreatic duct syndrome (DPDS) with viable upstream pancreas draining out of a low-pressure fistula created surgically or by a percutaneous catheter. The EPF can persist for months to years, and distal pancreatectomy, often the only permanent solution, carries a high morbidity and defined mortality. To describe 3 endoscopic and percutaneous rendezvous techniques to completely resolve EPFs in the setting of DPDS. A retrospective review of a prospective database of 15 patients who underwent rendezvous internalization of EPFs. Tertiary-care pancreatic referral center. Fifteen patients between October 2002 and October 2011 with EPFs in the setting of DPDS and resolved WOPN. Three rendezvous techniques that combined endoscopic and percutaneous procedures to internalize EPFs by transgastric, transduodenal, or transpapillary methods. EPF resolution and morbidity. Fifteen patients (12 men) with a median age of 51 years (range 24-65 years) with EPFs and DPDS (cutoff/blowout of pancreatic duct, with inability to demonstrate upstream body/tail of pancreas on pancreatogram) resulting from severe necrotizing pancreatitis underwent 1 of 3 rendezvous procedures to eliminate the EPFs. All patients were either poor surgical candidates or refused surgery. At the time of the rendezvous procedure, WOPN had fully resolved, DPDS was confirmed on pancreatography, and the EPF had persisted for a median of 5 months (range 1-48 months), producing a median output of 200 mL/day (range 50-700 mL/day). The rendezvous technique in 10 patients used the existing percutaneous drainage fistula to puncture into the stomach/duodenum to deliver wires that were captured endoscopically. The transenteric fistula was dilated and two

Usefulness of the rendezvous technique for biliary stricture after adult right-lobe living-donor liver transplantation with duct-to-duct anastomosis.

Science.gov (United States)

Chang, Jae Hyuck; Lee, In Seok; Chun, Ho Jong; Choi, Jong Young; Yoon, Seung Kyoo; Kim, Dong Goo; You, Young Kyoung; Choi, Myung-Gyu; Choi, Kyu-Yong; Chung, In-Sik

2010-03-01

Replacement of a percutaneous transhepatic biliary drainage (PTBD) catheter with inside stents using endoscopic retrograde cholangiography is difficult in patients with angulated or twisted biliary anastomotic stricture after living donor liver transplantation (LDLT). We evaluated the usefulness and safety of the rendezvous technique for the management of biliary stricture after LDLT. Twenty patients with PTBD because of biliary stricture after LDLT with duct-to-duct anastomosis underwent the placement of inside stents using the rendezvous technique. Inside stents were successfully placed in the 20 patients using the rendezvous technique. The median procedure time was 29.6 (range, 7.5-71.8) minutes. The number of inside stents placed was one in 12 patients and two in eight patients. One mild acute pancreatitis and one acute cholangitis occurred, which improved within a few days. Inside stent related sludge or stone was identified in 12 patients during follow-up. Thirteen patients achieved stent-free status for a median of 281 (range, 70-1,351) days after removal of the inside stents. The rendezvous technique is a useful and safe method for the replacement of PTBD catheter with inside stent in patients with biliary stricture after LDLT with duct-to-duct anastomosis. The rendezvous technique could be recommended to patients with angulated or twisted strictures.

The era of 3Rs implementation in developmental and reproductive toxicity (DART) testing: Current overview and future perspectives.

Science.gov (United States)

Beekhuijzen, Manon

2017-09-01

Since adoption of the first globally implemented guidelines for developmental and reproductive toxicity (DART) testing for pharmaceuticals, industrial chemicals and agrochemicals, many years passed without major updates. However in recent years, significant changes in these guidelines have been made or are being implemented. These changes have been guided by the ethical drive to reduce, refine and replace (3R) animal testing, as well as the addition of endocrine disruptor relevant endpoints. Recent applied improvements have focused on reduction and refinement. Ongoing scientific and technical innovations will provide the means for replacement of animal testing in the future and will improve predictivity in humans. The aim of this review is to provide an overview of ongoing global DART endeavors in respect to the 3Rs, with an outlook towards future advances in DART testing aspiring to reduce animal testing to a minimum and the supreme ambition towards animal-free hazard and risk assessment. Copyright © 2017 Elsevier Inc. All rights reserved.

Spacecraft Rendezvous Guidance in Cluttered Dynamical Environments via Extreme Learning Machines, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — DeepAnalytX, Inc. proposes to investigate a new approach to perform real-time, closed-loop optimal and robust rendezvous guidance in space environments comprising a...

Current status of laparoendoscopic rendezvous in the treatment of cholelithiasis with concomitant choledocholithiasis.

Science.gov (United States)

Baloyiannis, Ioannis; Tzovaras, George

2015-06-25

The current evidence in favor of the laparoendoscopic rendezvous is promising and demonstrates the main advantages of this technique in regard to shorter hospital stay and selective cannulation of the common bile duct (CBD), avoiding thus the inadvertent cannulation of the pancreatic duct. In addition, in the rendezvous technique the contrast medium is not injected retrogradely as during the traditional endoscopic retrograde cholangiopancreatography (ERCP), when the medium accidentally could be injected under pressure into the pancreatic duct. The RV technique minimizes that risk. Both these main advantages of the RV technique over the classic ERCP, are related with a significant lower incidence of hyperamylasemia and post-ERCP pancreatitis, compared with the traditional two stage procedure. Choledocholithiasis is present in 10% to 15% of patients undergoing cholecystectomy. To date, the ideal management of CBD stones remains controversial. Prospective randomized trials have shown that laparoscopic management of the CBD stones, as a single stage procedure, is the most efficient and cost effective method of treatment. Laparoendoscopic rendezvous has been proposed as an alternative single stage approach. Several studies have shown the effective use of this technique in the treatment of CBD stones by improving patient compliance and clinical results including shorter hospital stay, higher success rate and less cost. The current evidence about the use of this technique presented in this review article is promising and demonstrates the main advantages of the procedure.

Integrated vision-based GNC for autonomous rendezvous and capture around Mars

Science.gov (United States)

Strippoli, L.; Novelli, G.; Gil Fernandez, J.; Colmenarejo, P.; Le Peuvedic, C.; Lanza, P.; Ankersen, F.

2015-06-01

Integrated GNC (iGNC) is an activity aimed at designing, developing and validating the GNC for autonomously performing the rendezvous and capture phase of the Mars sample return mission as defined during the Mars sample return Orbiter (MSRO) ESA study. The validation cycle includes testing in an end-to-end simulator, in a real-time avionics-representative test bench and, finally, in a dynamic HW in the loop test bench for assessing the feasibility, performances and figure of merits of the baseline approach defined during the MSRO study, for both nominal and contingency scenarios. The on-board software (OBSW) is tailored to work with the sensors, actuators and orbits baseline proposed in MSRO. The whole rendezvous is based on optical navigation, aided by RF-Doppler during the search and first orbit determination of the orbiting sample. The simulated rendezvous phase includes also the non-linear orbit synchronization, based on a dedicated non-linear guidance algorithm robust to Mars ascent vehicle (MAV) injection accuracy or MAV failures resulting in elliptic target orbits. The search phase is very demanding for the image processing (IP) due to the very high visual magnitude of the target wrt. the stellar background, and the attitude GNC requires very high pointing stability accuracies to fulfil IP constraints. A trade-off of innovative, autonomous navigation filters indicates the unscented Kalman filter (UKF) as the approach that provides the best results in terms of robustness, response to non-linearities and performances compatibly with computational load. At short range, an optimized IP based on a convex hull algorithm has been developed in order to guarantee LoS and range measurements from hundreds of metres to capture.

Manned maneuvering unit applications for automated rendezvous and capture

Science.gov (United States)

Brehm, Donald L.; Cuseo, John A.; Lenda, Joseph A.; Ray, Lex; Whitsett, C. Edward

Automated Rendezvous and Capture (AR&C) is an important technology to multiple National Aeronautics and Space Administration (NASA) programs and centers. The recent Johnson Spacecraft Center (JSC) AR&C Quality Function Deployment (QFD) has listed on-orbit demonstration of related technologies as a near term priority. Martin Marietta has been evaluating use of the Manned Maneuvering Unit (MMU) for a low cost near term on-orbit demonstration of AR&C technologies such as control algorithms, sensors, and processors as well as system level performance. The MMU Program began in 1979 as the method of repairing the Space Shuttle (STS) Thermal Protection System (the tiles). The units were not needed for this task, but were successfully employed during three Shuttle flights in 1984: a test flight was flown in in February as proof of concept, in April the MMU participated in the Solar Max Repair Mission, and in November the MMU's returned to space to successfully rescue the two errant satellites, Westar and Palapa. In the intervening years, the MMU simulator and MMU Qualification Test Unit (QTU) have been used for Astronaut training and experimental evaluations. The Extra-Vehicular Activities (EVA) Retriever has used the QTU, in an unmanned form, as a free-flyer on the Johnson Space Center (JSC) Precision Air Bearing Floor (PABF). Currently, the MMU is undergoing recertification for flight. The two flight units were removed from storage in September, 1991 and evaluation tests were performed. The tests demonstrated that the units are in good shape with no discrepancies that would preclude further use. The Return to Flight effort is currently clearing up recertification issues and evaluating the design against the present Shuttle environments.

Access to CAMAC from VxWorks and UNIX in DART

International Nuclear Information System (INIS)

Streets, J.; Meadows, J.; Moore, C.

1995-05-01

As part of the DART Project the authors have developed a package of software for CAMAC access from UNIX and VxWorks platforms, with support for several hardware interfaces. They report on developments for the CES CBD8210 VME to parallel CAMAC, the Hytec VSD2992 VME to serial CAMAC and Jorway 411S SCSI to parallel and serial CAMAC branch drivers, and give a summary of the timings obtained

Temperature-dependent release of volatile organic compounds of eucalypts by direct analysis in real time (DART) mass spectrometry.

Science.gov (United States)

Maleknia, Simin D; Vail, Teresa M; Cody, Robert B; Sparkman, David O; Bell, Tina L; Adams, Mark A

2009-08-01

A method is described for the rapid identification of biogenic, volatile organic compounds (VOCs) emitted by plants, including the analysis of the temperature dependence of those emissions. Direct analysis in real time (DART) enabled ionization of VOCs from stem and leaf of several eucalyptus species including E. cinerea, E. citriodora, E. nicholii and E. sideroxylon. Plant tissues were placed directly in the gap between the DART ionization source skimmer and the capillary inlet of the time-of-flight (TOF) mass spectrometer. Temperature-dependent emission of VOCs was achieved by adjusting the temperature of the helium gas into the DART ionization source at 50, 100, 200 and 300 degrees C, which enabled direct evaporation of compounds, up to the onset of pyrolysis of plant fibres (i.e. cellulose and lignin). Accurate mass measurements facilitated by TOF mass spectrometry provided elemental compositions for the VOCs. A wide range of compounds was detected from simple organic compounds (i.e. methanol and acetone) to a series of monoterpenes (i.e. pinene, camphene, cymene, eucalyptol) common to many plant species, as well as several less abundant sesquiterpenes and flavonoids (i.e. naringenin, spathulenol, eucalyptin) with antioxidant and antimicrobial properties. The leaf and stem tissues for all four eucalypt species showed similar compounds. The relative abundances of methanol and ethanol were greater in stem wood than in leaf tissue suggesting that DART could be used to investigate the tissue-specific transport and emissions of VOCs. Copyright (c) 2009 John Wiley & Sons, Ltd.

The mobile agent rendezvous problem in the ring

CERN Document Server

Kranakis, Evangelos; Marcou, Euripides

2010-01-01

Mobile agent computing is being used in fields as diverse as artificial intelligence, computational economics and robotics. Agents' ability to adapt dynamically and execute asynchronously and autonomously brings potential advantages in terms of fault-tolerance, flexibility and simplicity. This monograph focuses on studying mobile agents as modelled in distributed systems research and in particular within the framework of research performed in the distributed algorithms community. It studies the fundamental question of how to achieve rendezvous, the gathering of two or more agents at the same n

NASA Double Asteroid Redirection Test (DART) Trajectory Validation and Robutness

Science.gov (United States)

Sarli, Bruno V.; Ozimek, Martin T.; Atchison, Justin A.; Englander, Jacob A.; Barbee, Brent W.

2017-01-01

The Double Asteroid Redirection Test (DART) mission will be the first to test the concept of a kinetic impactor. Several studies have been made on asteroid redirection and impact mitigation, however, to this date no mission tested the proposed concepts. An impact study on a representative body allows the measurement of the effects on the target's orbit and physical structure. With this goal, DART's objective is to verify the effectiveness of the kinetic impact concept for planetary defense. The spacecraft uses solar electric propulsion to escape Earth, fly by (138971) 2001 CB21 for impact rehearsal, and impact Didymos-B, the secondary body of the binary (65803) Didymos system. This work focuses on the heliocentric transfer design part of the mission with the validation of the baseline trajectory, performance comparison to other mission objectives, and assessment of the baseline robustness to missed thrust events. Results show a good performance of the selected trajectory for different mission objectives: latest possible escape date, maximum kinetic energy on impact, shortest possible time of flight, and use of an Earth swing-by. The baseline trajectory was shown to be robust to a missed thrust with 1% of fuel margin being enough to recover the mission for failures of more than 14 days.

DART: a simulation code for charged particle beams

International Nuclear Information System (INIS)

White, R.C.; Barr, W.L.; Moir, R.W.

1988-01-01

This paper presents a recently modified verion of the 2-D DART code designed to simulate the behavior of a beam of charged particles whose paths are affected by electric and magnetic fields. This code was originally used to design laboratory-scale and full-scale beam direct converters. Since then, its utility has been expanded to allow more general applications. The simulation technique includes space charge, secondary electron effects, and neutral gas ionization. Calculations of electrode placement and energy conversion efficiency are described. Basic operation procedures are given including sample input files and output. 7 refs., 18 figs

Curare Alkaloids: Constituents of a Matis Dart Poison.

Science.gov (United States)

Malca Garcia, Gonzalo R; Hennig, Lothar; Shelukhina, Irina V; Kudryavtsev, Denis S; Bussmann, Rainer W; Tsetlin, Victor I; Giannis, Athanassios

2015-11-25

A phytochemical study of dart and arrow poison from the Matis tribe led to the identification of D-(-)-quinic acid, L-malic acid, ethyldimethylamine, magnoflorine, and five new bisbenzyltetrahydroisoquinoline alkaloids (BBIQAs), 1-5. D-Tubocurarine could not be identified among these products. BBIQA (3) contains a unique linkage at C-8 and C-11'. All structures were characterized by a combination of NMR and HRESIMS data. The effects of Matis poison and individual BBIQAs (1-3) on rat muscle nAChR expressed in Xenopus oocytes have been investigated using the two-electrode voltage clamp technique.

Design and implementation of a dexterous anthropomorphic robotic typing (DART) hand

International Nuclear Information System (INIS)

Thayer, Nicholas; Priya, Shashank

2011-01-01

This paper focuses on design and implementation of a biomimetic dexterous humanoid hand. Several design rules are proposed to retain human form and functionality in a robotic hand while overcoming the difficultly of actuation within a confined geometry. Size and weight have been optimized in order to achieve human-like performance with the prime objective of typing on a computer keyboard. Each finger has four joints and three degrees of freedom (DOF) while the thumb has an additional degree of freedom necessary for manipulating small objects. The hand consists of 16 servo motors dedicated to finger motion and three motors for wrist motion. A closed-loop kinematic control scheme utilizing the Denavit–Hartenberg convention for spatial joint positioning was implemented. Servo motors housed in the forearm act as an origin for wires to travel to their insertion points in the hand. The dexterity of the DART hand was measured by quantifying functionality and typing speed on a standard keyboard. The typing speed of a single DART hand was found to be 20 words min −1 . In comparison, the average human has a typing speed of 33 words min −1 with two hands

DART: a robust algorithm for fast reconstruction of three-dimensional grain maps

DEFF Research Database (Denmark)

Batenburg, K.J.; Sijbers, J.; Poulsen, Henning Friis

2010-01-01

and moderate noise levels, DART is shown to generate essentially perfect two-dimensional grain maps for as few as three projections per grain with running times on a PC in the range of less than a second. This is seen as opening up the possibility for fast reconstructions in connection with in situ studies....

The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer

International Nuclear Information System (INIS)

Slattery, S. R.; Wilson, P. P. H.; Pawlowski, R. P.

2013-01-01

The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)

The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer

Energy Technology Data Exchange (ETDEWEB)

Slattery, S. R.; Wilson, P. P. H. [Department of Engineering Physics, University of Wisconsin - Madison, 1500 Engineering Dr., Madison, WI 53706 (United States); Pawlowski, R. P. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

2013-07-01

The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)

Detection of nitro-organic and peroxide explosives in latent fingermarks by DART- and SALDI-TOF-mass spectrometry.

Science.gov (United States)

Rowell, Frederick; Seviour, John; Lim, Angelina Yimei; Elumbaring-Salazar, Cheryl Grace; Loke, Jason; Ma, Jan

2012-09-10

The ability of two mass spectrometric methods, surface-assisted laser desorption/ionization-time of flight-mass spectrometry (SALDI-TOF-MS) and direct analysis in real time (DART-MS), to detect the presence of seven common explosives (six nitro-organic- and one peroxide-type) in spiked latent fingermarks has been examined. It was found that each explosive could be detected with nanogram sensitivity for marks resulting from direct finger contact with a glass probe by DART-MS or onto stainless steel target plates using SALDI-TOF-MS for marks pre-dusted with one type of commercial black magnetic powder. These explosives also could be detected in latent marks lifted from six common surfaces (paper, plastic bag, metal drinks can, wood laminate, adhesive tape and white ceramic tile) whereas no explosive could be detected in equivalent pre-dusted marks on the surface of a commercial lifting tape by the DART-MS method due to high background interference from the tape material. The presence of TNT and Tetryl could be detected in pre-dusted latent fingermarks on a commercial lifting tape for up to 29 days sealed and stored under ambient conditions. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Authentication of animal fats using direct analysis in real time (DART) ionization-mass spectrometry and chemometric tools.

Science.gov (United States)

Vaclavik, Lukas; Hrbek, Vojtech; Cajka, Tomas; Rohlik, Bo-Anne; Pipek, Petr; Hajslova, Jana

2011-06-08

A combination of direct analysis in real time (DART) ionization coupled to time-of-flight mass spectrometry (TOFMS) and chemometrics was used for animal fat (lard and beef tallow) authentication. This novel instrumentation was employed for rapid profiling of triacylglycerols (TAGs) and polar compounds present in fat samples and their mixtures. Additionally, fat isolated from pork, beef, and pork/beef admixtures was analyzed. Mass spectral records were processed by principal component analysis (PCA) and stepwise linear discriminant analysis (LDA). DART-TOFMS profiles of TAGs were found to be more suitable for the purpose of discrimination among the examined fat types as compared to profiles of polar compounds. The LDA model developed using TAG data enabled not only reliable classification of samples representing neat fats but also detection of admixed lard and tallow at adulteration levels of 5 and 10% (w/w), respectively. The presented approach was also successfully applied to minced meat prepared from pork and beef with comparable fat content. Using the DART-TOFMS TAG profiles of fat isolated from meat mixtures, detection of 10% pork added to beef and vice versa was possible.

Rendezvous terminal phase automatic braking sequencing and targeting. [for space shuttle orbiter

Science.gov (United States)

Kachmar, P. M.

1973-01-01

The purpose of the rendezvous terminal phase braking program is to provide the means of automatically bringing the primary orbiter within desired station keeping boundaries relative to the target satellite. A detailed discussion is presented on the braking program and its navigation, targeting, and guidance functions.

An Application of Linear Covariance Analysis to the Design of Responsive Near-Rendezvous Missions

National Research Council Canada - National Science Library

Visser, Benjamin L

2007-01-01

This thesis investigates a new class of launch vehicles capable of being released from an aircraft which ultimately have the goal of achieving near-rendezvous conditions at orbital altitudes up to 800 km...

AIDA: Asteroid Impact & Deflection Assessment

Science.gov (United States)

Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

2012-12-01

To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

Q-Learning and p-persistent CSMA based rendezvous protocol for cognitive radio networks operating with shared spectrum activity

Science.gov (United States)

Watson, Clifton L.; Biswas, Subir

2014-06-01

With an increasing demand for spectrum, dynamic spectrum access (DSA) has been proposed as viable means for providing the flexibility and greater access to spectrum necessary to meet this demand. Within the DSA concept, unlicensed secondary users temporarily "borrow" or access licensed spectrum, while respecting the licensed primary user's rights to that spectrum. As key enablers for DSA, cognitive radios (CRs) are based on software-defined radios which allow them to sense, learn, and adapt to the spectrum environment. These radios can operate independently and rapidly switch channels. Thus, the initial setup and maintenance of cognitive radio networks are dependent upon the ability of CR nodes to find each other, in a process known as rendezvous, and create a link on a common channel for the exchange of data and control information. In this paper, we propose a novel rendezvous protocol, known as QLP, which is based on Q-learning and the p-persistent CSMA protocol. With the QLP protocol, CR nodes learn which channels are best for rendezvous and thus adapt their behavior to visit those channels more frequently. We demonstrate through simulation that the QLP protocol provides a rendevous capability for DSA environments with different dynamics of PU activity, while attempting to achieve the following performance goals: (1) minimize the average time-to-rendezvous, (2) maximize system throughput, (3) minimize primary user interference, and (4) minimize collisions among CR nodes.

Ambient mass spectrometry employing direct analysis in real time (DART) ion source for olive oil quality and authenticity assessment

International Nuclear Information System (INIS)

Vaclavik, Lukas; Cajka, Tomas; Hrbek, Vojtech; Hajslova, Jana

2009-01-01

A novel approach for the authentication of olive oil samples representing different quality grades has been developed. A new type of ion source, direct analysis in real time (DART), coupled to a high-resolution time-of-flight mass spectrometer (TOFMS) was employed for the comprehensive profiling of triacylglycerols (TAGs) and/or polar compounds extracted with a methanol-water mixture. The main parameters influencing the ionization efficiency of TAGs were the type of sample solvent, degree of sample dilution, ion beam temperature, and presence of a dopant (ammonia vapors). The ionization yield of polar compounds depended mainly on a content of water in the extract and ion beam temperature. Using DART-TOFMS, not only differentiation among extra virgin olive oil (EVOO), olive pomace oil (OPO) and olive oil (OO) could be easily achieved, but also EVOO adulteration with commonly used adulterant, hazelnut oil (HO), was feasible. Based on the linear discriminant analysis (LDA), the introduced method allowed detection of HO addition of 6 and 15% (v/v) when assessing DART-TOFMS mass profiles of polar compounds and TAGs, respectively.

Ambient mass spectrometry employing direct analysis in real time (DART) ion source for olive oil quality and authenticity assessment

Energy Technology Data Exchange (ETDEWEB)

Vaclavik, Lukas; Cajka, Tomas; Hrbek, Vojtech [Institute of Chemical Technology Prague, Faculty of Food and Biochemical Technology, Department of Food Chemistry and Analysis, Technicka 5, 166 28 Prague 6 (Czech Republic); Hajslova, Jana, E-mail: jana.hajslova@vscht.cz [Institute of Chemical Technology Prague, Faculty of Food and Biochemical Technology, Department of Food Chemistry and Analysis, Technicka 5, 166 28 Prague 6 (Czech Republic)

2009-07-10

A novel approach for the authentication of olive oil samples representing different quality grades has been developed. A new type of ion source, direct analysis in real time (DART), coupled to a high-resolution time-of-flight mass spectrometer (TOFMS) was employed for the comprehensive profiling of triacylglycerols (TAGs) and/or polar compounds extracted with a methanol-water mixture. The main parameters influencing the ionization efficiency of TAGs were the type of sample solvent, degree of sample dilution, ion beam temperature, and presence of a dopant (ammonia vapors). The ionization yield of polar compounds depended mainly on a content of water in the extract and ion beam temperature. Using DART-TOFMS, not only differentiation among extra virgin olive oil (EVOO), olive pomace oil (OPO) and olive oil (OO) could be easily achieved, but also EVOO adulteration with commonly used adulterant, hazelnut oil (HO), was feasible. Based on the linear discriminant analysis (LDA), the introduced method allowed detection of HO addition of 6 and 15% (v/v) when assessing DART-TOFMS mass profiles of polar compounds and TAGs, respectively.

Rendezvous, un juego de Lewis Carroll

Directory of Open Access Journals (Sweden)

José Manuel Sánchez Muñoz

2011-10-01

Full Text Available Todos en mayor o menor medida asociamos el nombre de Lewis Carrolla la literatura, sobre todo a la de temática infantil, con títulos a sus espaldas como Alicia en el País de las Maravillas, Alicia a través del espejo, o La Caza del Snark. Pero además de literato, Lewis Carrol fue un hombre con bastantes inquietudes en torno a la matemática, la lógica y el pensamiento filosófico. Pero no todo el mundo es conocedor de su faceta como creativo en el campo de los juegos. Rendezvous es una de sus más sorprendentes invenciones,un juego de inteligencia para todos los públicos, cuyas directrices hacen de él un entretenimiento bastante original.

Hamburgian weapon delivery technology: a quantitative comparative approach

DEFF Research Database (Denmark)

Riede, Felix

2010-01-01

cran). Numerous studies have addressed the question of whether these points tipped arrows fired from bows, darts launched with the help of spear-throwers, or some other projectile delivery weapon. This paper approaches the question of Hamburgian weapon delivery technology from a quantitative...

Early Twentieth Century Arrow, Javelin, and Dart Games of the Western Native American.

Science.gov (United States)

Pesavento, Wilma J.

The general purpose of this study was to determine whether the traditional native American ball games continued to be positive culture traits of the American Indian in the early twentieth century. The investigation was centered about (1) determining the current arrow, javelin, and dart games of western native Americans, (2) determining the…

Laparoscopic-endoscopic rendezvous versus preoperative endoscopic sphincterotomy in people undergoing laparoscopic cholecystectomy for stones in the gallbladder and bile duct.

Science.gov (United States)

Vettoretto, Nereo; Arezzo, Alberto; Famiglietti, Federico; Cirocchi, Roberto; Moja, Lorenzo; Morino, Mario

2018-04-11

The management of gallbladder stones (lithiasis) concomitant with bile duct stones is controversial. The more frequent approach is a two-stage procedure, with endoscopic sphincterotomy and stone removal from the bile duct followed by laparoscopic cholecystectomy. The laparoscopic-endoscopic rendezvous combines the two techniques in a single-stage operation. To compare the benefits and harms of endoscopic sphincterotomy and stone removal followed by laparoscopic cholecystectomy (the single-stage rendezvous technique) versus preoperative endoscopic sphincterotomy followed by laparoscopic cholecystectomy (two stages) in people with gallbladder and common bile duct stones. We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, Science Citation Index Expanded Web of Science, and two trials registers (February 2017). We included randomised clinical trials that enrolled people with concomitant gallbladder and common bile duct stones, regardless of clinical status or diagnostic work-up, and compared laparoscopic-endoscopic rendezvous versus preoperative endoscopic sphincterotomy procedures in people undergoing laparoscopic cholecystectomy. We excluded other endoscopic or surgical methods of intraoperative clearance of the bile duct, e.g. non-aided intraoperative endoscopic retrograde cholangiopancreatography or laparoscopic choledocholithotomy (surgical incision of the common bile duct for removal of bile duct stones). We used standard methodological procedures recommended by Cochrane. We included five randomised clinical trials with 517 participants (257 underwent a laparoscopic-endoscopic rendezvous technique versus 260 underwent a sequential approach), which fulfilled our inclusion criteria and provided data for analysis. Trial participants were scheduled for laparoscopic cholecystectomy because of suspected cholecysto-choledocholithiasis. Male/female ratio was 0.7; age of men and women ranged from 21 years to 87

Inverse simulation system for evaluating handling qualities during rendezvous and docking

Science.gov (United States)

Zhou, Wanmeng; Wang, Hua; Thomson, Douglas; Tang, Guojin; Zhang, Fan

2017-08-01

The traditional method used for handling qualities assessment of manned space vehicles is too time-consuming to meet the requirements of an increasingly fast design process. In this study, a rendezvous and docking inverse simulation system to assess the handling qualities of spacecraft is proposed using a previously developed model-predictive-control architecture. By considering the fixed discrete force of the thrusters of the system, the inverse model is constructed using the least squares estimation method with a hyper-ellipsoidal restriction, the continuous control outputs of which are subsequently dispersed by pulse width modulation with sensitivity factors introduced. The inputs in every step are deemed constant parameters, and the method could be considered as a general method for solving nominal, redundant, and insufficient inverse problems. The rendezvous and docking inverse simulation is applied to a nine-degrees-of-freedom platform, and a novel handling qualities evaluation scheme is established according to the operation precision and astronauts' workload. Finally, different nominal trajectories are scored by the inverse simulation and an established evaluation scheme. The scores can offer theoretical guidance for astronaut training and more complex operation missions.

Failed common bile duct cannulation during pregnancy: Rescue with endoscopic ultrasound guided rendezvous procedure.

Science.gov (United States)

Singla, Vikas; Arora, Anil; Tyagi, Pankaj; Sharma, Praveen; Bansal, Naresh; Kumar, Ashish

2016-01-01

Common bile duct (CBD) stones can lead to serious complications and require intervention with either endoscopic retrograde cholangiopancreatography (ERCP) or laparoscopic techniques for urgent relief. On an average 10%-20% of the patients with gall bladder stones can have associated CBD stones. CBD stones during pregnancy can be associated with hazardous complications for both the mother and the fetus. Failed cannulation while performing ERCP during pregnancy is a technically demanding situation, which requires immediate rescue with special techniques. Conventional rescue techniques may not be feasible and can be associated with hazardous consequences. Endoscopic ultrasound (EUS) guided rendezvous technique has now emerged as a safe alternative, and in one of our patients, this technique was successfully attempted. To the best of our knowledge, this is the first case report in the literature on EUS-guided rendezvous procedure during pregnancy.

Changes in allelic frequency over time in European bread wheat (Triticum aestivum L.) varieties revealed using DArT and SSR markers

DEFF Research Database (Denmark)

Orabi, Jihad; Jahoor, Ahmed; Backes, Gunter Martin

2014-01-01

A collection of 189 bread wheat landraces and cultivars, primarily of European origin, released between 1886 and 2009, was analyzed using two DNA marker systems. A set of 76 SSR markers and ~7,000 DArT markers distributed across the wheat genome were employed in these analyses. All of the SSR...... markers were found to be polymorphic, whereas only 2,532 of the ~7,000 DArT markers were polymorphic. A Mantel test between the genetic distances calculated based on the SSR and DArT data showed a strong positive correlation between the two marker types, with a Pearson's value (r) of 0.66. We assessed...... the genetic diversity and allelic frequencies among the accessions based on spring- versus winter-wheat type as well as between landraces and cultivars. We also analyzed the changes in genetic diversity and allelic frequencies in these samples over time. We observed separation based on both vernalization type...

AVGS, AR and D for Satellites, ISS, the Moon, Mars and Beyond

Science.gov (United States)

Hintze, Geoffrey C.; Cornett, Keith G.; Rahmatipour, Michael H.; Heaton, Andrew F.; Newman, Larry E.; Fleischmann, Kevin D.; Hamby, Byron J.

2007-01-01

With the continuous need to rotate crew and re-supply the International Space Station (ISS) and the desire to return humans to the Moon and for the first time, place humans on Mars, NASA must develop a more robust and highly reliable capability to perform Autonomous Rendezvous and Capture (AR&C) because, unlike the Apollo missions, NASA plans to send the entire crew to the Lunar or Martian surface and must be able to dock with the Orion spacecraft upon return. In 1997, NASA developed the Video Guidance Sensor (VGS) which was flown and tested on STS-87 and STS-95. In 2001, NASA designed and built a more enhanced version of the VGS, called the Advanced Video Guidance Sensor (AVGS). The AVGS offered significant technology improvements to the precursor VGS design. This paper will describe the AVGS as it was in the DART mission of 2005 and the Orbital Express mission of 2007. The paper will describe the capabilities and design concepts of the AVGS as it was flown on the DART 2005 Mission and the DARPA Orbital Express Mission slated to fly in 2007. The paper will cover the Flight Software, problems encountered, testing for Orbital Express and where NASA is going in the future.

A Universal Semi-totalistic Cellular Automaton on Kite and Dart Penrose Tilings

Directory of Open Access Journals (Sweden)

Katsunobu Imai

2012-08-01

Full Text Available In this paper we investigate certain properties of semi-totalistic cellular automata (CA on the well known quasi-periodic kite and dart two dimensional tiling of the plane presented by Roger Penrose. We show that, despite the irregularity of the underlying grid, it is possible to devise a semi-totalistic CA capable of simulating any boolean circuit on this aperiodic tiling.

Planetary mission requirements, technology and design considerations for a solar electric propulsion stage

Science.gov (United States)

Cork, M. J.; Hastrup, R. C.; Menard, W. A.; Olson, R. N.

1979-01-01

High energy planetary missions such as comet rendezvous, Saturn orbiter and asteroid rendezvous require development of a Solar Electric Propulsion Stage (SEPS) for augmentation of the Shuttle-IUS. Performance and functional requirements placed on the SEPS are presented. These requirements will be used in evolution of the SEPS design, which must be highly interactive with both the spacecraft and the mission design. Previous design studies have identified critical SEPS technology areas and some specific design solutions which are also presented in the paper.

Javelin, Arrow, Dart and Pin Games of Native American Women of the Plains.

Science.gov (United States)

Pesavento, Wilma J.; Pesavento, Lisa C.

This study was designed to determine (1) the arrow, dart, javelin, and pin games of Native American girls and women of the Great Plains, (2) the geographical spread of the games within the culture area, and (3) the characteristics of the various games. Data for this investigation were researched from "Annual Reports of the Bureau of American…

DART-TM: A thermomechanical version of DART for LEU VHD dispersed and monolithic fuel analysis

International Nuclear Information System (INIS)

Saliba, Roberto; Taboada, Horacio; Moscarda, Ma.Virginia; Rest, Jeff

2003-01-01

A collaboration agreement between ANL/USDOE and CNEA Argentina, in the area of Low Enriched Uranium Advanced Fuels has been in place since October 16, 1997 under the 'Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy'. An annex concerning DART code optimization has been operative since February 8, 1999. Previously, as a part of this annex a visual thermal FASTDART version was developed that includes mechanistic models for the calculation of the fission-gas-bubble and fuel particle size distribution, reaction layer thickness, and meat thermal conductivity. FASTDART was presented at the last RERTR Meeting that included validation against RERTR 3 irradiation data. The thermal FASTDART version was assessed as an adequate tool for modeling the behavior of LEU U-Mo dispersed fuels under irradiation against PIE RERTR irradiation data. During this past year the development of a 3-D thermo-mechanical version of the code for modeling the irradiation behavior of LEU U-Mo monolithic and dispersion fuel was initiated. Some preliminary results of this work will be shown during RERTR-2003 meeting. (author)

Evaluation of remote delivery of Passive Integrated Transponder (PIT technology to mark large mammals.

Directory of Open Access Journals (Sweden)

W David Walter

Full Text Available Methods to individually mark and identify free-ranging wildlife without trapping and handling would be useful for a variety of research and management purposes. The use of Passive Integrated Transponder technology could be an efficient method for collecting data for mark-recapture analysis and other strategies for assessing characteristics about populations of various wildlife species. Passive Integrated Transponder tags (PIT have unique numbered frequencies and have been used to successfully mark and identify mammals. We tested for successful injection of PIT and subsequent functioning of PIT into gelatin blocks using 4 variations of a prototype dart. We then selected the prototype dart that resulted in the least depth of penetration in the gelatin block to assess the ability of PIT to be successfully implanted into muscle tissue of white-tailed deer (Odocoileus virginianus post-mortem and long-term in live, captive Rocky Mountain elk (Cervus elaphus. The prototype dart with a 12.7 mm (0.5 inch needle length and no powder charge resulted in the shallowest mean (± SD penetration depth into gelatin blocks of 27.0 mm (± 5.6 mm with 2.0 psi setting on the Dan-Inject CO(2-pressured rifle. Eighty percent of PIT were successfully injected in the muscle mass of white-tailed deer post-mortem with a mean (± SD penetration depth of 22.2 mm (± 3.8 mm; n = 6. We injected PIT successfully into 13 live, captive elk by remote delivery at about 20 m that remained functional for 7 months. We successfully demonstrated that PIT could be remotely delivered in darts into muscle mass of large mammals and remain functional for >6 months. Although further research is warranted to fully develop the technique, remote delivery of PIT technology to large mammals is possible using prototype implant darts.

Quadratic Polynomial Regression using Serial Observation Processing:Implementation within DART

Science.gov (United States)

Hodyss, D.; Anderson, J. L.; Collins, N.; Campbell, W. F.; Reinecke, P. A.

2017-12-01

Many Ensemble-Based Kalman ltering (EBKF) algorithms process the observations serially. Serial observation processing views the data assimilation process as an iterative sequence of scalar update equations. What is useful about this data assimilation algorithm is that it has very low memory requirements and does not need complex methods to perform the typical high-dimensional inverse calculation of many other algorithms. Recently, the push has been towards the prediction, and therefore the assimilation of observations, for regions and phenomena for which high-resolution is required and/or highly nonlinear physical processes are operating. For these situations, a basic hypothesis is that the use of the EBKF is sub-optimal and performance gains could be achieved by accounting for aspects of the non-Gaussianty. To this end, we develop here a new component of the Data Assimilation Research Testbed [DART] to allow for a wide-variety of users to test this hypothesis. This new version of DART allows one to run several variants of the EBKF as well as several variants of the quadratic polynomial lter using the same forecast model and observations. Dierences between the results of the two systems will then highlight the degree of non-Gaussianity in the system being examined. We will illustrate in this work the differences between the performance of linear versus quadratic polynomial regression in a hierarchy of models from Lorenz-63 to a simple general circulation model.

Dry-season retreat and dietary shift of the dart-poison frog Dendrobates tinctorius (Anura: Dendrobatidae)

NARCIS (Netherlands)

Born, M.; Bongers, F.; Poelman, E.H.; Sterck, F.J.

2010-01-01

Dry-season retreat and dietary shift of the dart-poison frog Delldrobates tillCtOrillS (Anura: Dendrobatidae). Seasonal rainfall affects tropical forest dynamics and behavior of species that are part of these ecosystems. TIle positive correlation between amphibian ac tivity pattems and rainfall has

Lyapunov design of event-based controllers for the rendez-vous of coupled systems

NARCIS (Netherlands)

De Persis, Claudio; Postoyan, Romain

2014-01-01

The objective is to present a new type of triggering conditions together with new proof concepts for the event-based coordination of multi-agents. As a first step, we focus on the rendez-vous of two identical systems modeled as double integrators with additional damping in the velocity dynamics. The

Analysis of carbohydrates in Fusarium verticillioides using size-exclusion HPLC – DRI and direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS)

Science.gov (United States)

Direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS) and size-exclusion HPLC – DRI are used, respectively, to qualitatively and quantitatively determine the carbohydrates extracted from the corn rot fungus Fusarium verticillioides. In situ permethylation in the DART...

Near-Earth Asteroid Rendezvous: mission overview

Science.gov (United States)

Cheng, A. F.; Santo, A. G.; Heeres, K. J.; Landshof, J. A.; Farquhar, R. W.; Gold, R. E.; Lee, S. C.

1997-10-01

The Near-Earth Asteroid Rendezvous (NEAR) mission, the first launch of NASA's Discovery Program, will be the first mission to orbit an asteroid. NEAR will make the first comprehensive scientific measurements of an asteroid's surface composition, geology, physical properties, and internal structure. NEAR launched successfully on February 17, 1996, aboard a Delta II-7925. It will orbit the 20-km-diameter near-Earth asteroid 433 Eros for about 1 year, at a minimum orbit radius of about 35 km from the center of the asteroid. The NEAR is a solar-powered, three-axis stabilized spacecraft with a launch mass including propellant of 805 kg. NEAR uses X band telemetry to the NASA Deep Space Network, with the data rates at Eros up to 8.8 kbits/s using a 34-m High Efficiency (HEF) dish, and up to 26.5 kbits/s using a 70-m dish. A solid-state recorder is accommodated with a memory capacity of 1.8 Gbytes. Attitude control is to 1.7 mrad, line-of-sight pointing stability is within 50 μrad over 1 s, and post processing attitude knowledge is within 50 μrad. NEAR accommodates 56 kg of instruments and provides them with 84 W. The instruments are a multispectral imager (MSI), a near-infrared spectrograph (NIS), an X ray/gamma ray spectrometer (XRS/GRS), a magnetometer (MAG), and a laser rangefinder (NLR), while a radio science (RS) investigation uses the coherent X band transponder. NEAR will make a flyby of the C-type asteroid 253 Mathilde in June 1997 and will rendezvous with 433 Eros in February 1999. It will execute an initial slow flyby of Eros, with a flyby speed of 5 m/s and a closest approach distance of 500 km. Subsequently, its orbit will be lowered to 35 km. The NEAR Mission Operations Center and the Science Data Center are at the Johns Hopkins Applied Physics Laboratory. The Science Data Center will maintain the entire NEAR data set on-line, and data from all instruments can be accessed by every member of the NEAR Science Team. Data, including images, are released over

A Parameter Study on the Effect of Impactor Size for NASA’s DART Mission

Science.gov (United States)

Truitt, Amanda; Weaver, Robert; Gisler, Galen

2018-06-01

We have modeled the impact of the Double Asteroid Redirection Test (DART) spacecraft into the binary near-Earth asteroid (65803) Didymos. While the primary object is approximately 800 meters across, its secondary body (“moonlet” Didymoon) has a diameter of 150 meters, which is thought to be a much more typical size for the kind of asteroid that would pose a hazard to Earth. DART will be the first demonstration of the kinetic impact technique to change the motion of an asteroid in space, an important consideration for understanding our capabilities in planetary defense of Near-Earth Asteroids. Recent modeling of this impact has used full-density solid aluminum spheres with a mass of approximately 500 kg. Many of the published scaling laws for crater size and diameter as well as ejecta modeling assume this type of impactor, although the actual spacecraft shape being considered for the DART Mission impact is not solid and does not contain a solid dedicated kinetic impactor – rather, the spacecraft itself is considered the impactor. Since the 500 kg hollow spacecraft is significantly larger (~100 x 100 x 200 cm) in size than a solid aluminum sphere (radius ~ 36 cm) the resulting impact dynamics are quite different. Here we have modeled both types of impacts and compare the results of the simulations for crater size, depth, and ejecta for a solid sphere (R = 36 cm) and cylindrical spacecraft (R = 20, 50, and 100 cm), while maintaining a constant mass and material density. This work will allow for a more robust comparison of the momentum enhancement β-factor, which describes the gain in a momentum transfer exerted by the impacting spacecraft on a Near-Earth Object due to ejecta momentum escape. (LA-UR-18-21571)

A Comparison Between Orion Automated and Space Shuttle Rendezvous Techniques

Science.gov (United States)

Ruiz, Jose O,; Hart, Jeremy

2010-01-01

The Orion spacecraft will replace the space shuttle and will be the first human spacecraft since the Apollo program to leave low earth orbit. This vehicle will serve as the cornerstone of a complete space transportation system with a myriad of mission requirements necessitating rendezvous to multiple vehicles in earth orbit, around the moon and eventually beyond . These goals will require a complex and robust vehicle that is, significantly different from both the space shuttle and the command module of the Apollo program. Historically, orbit operations have been accomplished with heavy reliance on ground support and manual crew reconfiguration and monitoring. One major difference with Orion is that automation will be incorporated as a key element of the man-vehicle system. The automated system will consist of software devoted to transitioning between events based on a master timeline. This effectively adds a layer of high level sequencing that moves control of the vehicle from one phase to the next. This type of automated control is not entirely new to spacecraft since the shuttle uses a version of this during ascent and entry operations. During shuttle orbit operations however many of the software modes and hardware switches must be manually configured through the use of printed procedures and instructions voiced from the ground. The goal of the automation scheme on Orion is to extend high level automation to all flight phases. The move towards automation represents a large shift from current space shuttle operations, and so these new systems will be adopted gradually via various safeguards. These include features such as authority-to-proceed, manual down modes, and functional inhibits. This paper describes the contrast between the manual and ground approach of the space shuttle and the proposed automation of the Orion vehicle. I will introduce typical orbit operations that are common to all rendezvous missions and go on to describe the current Orion automation

Rendezvous cannulation technique reduces post-ERCP pancreatitis: a prospective nationwide study of 12,718 ERCP procedures.

Science.gov (United States)

Swahn, Fredrik; Nilsson, Magnus; Arnelo, Urban; Löhr, Matthias; Persson, Gunnar; Enochsson, Lars

2013-04-01

The aim of this study was to investigate if intraoperative rendezvous cannulation reduces the risk of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) because there is no universal consensus on the optimal treatment of common bile duct stones. We performed a nationwide case-control study, nested within the cohort of ERCP procedures reported to the Swedish Registry for Gallstone Surgery and ERCP (GallRiks), between 2007 and 2009. Data were collected prospectively from a web-based registry of ERCP procedures that includes variables such as patient characteristics, indication, cannulation technique, diagnostic findings, therapeutic measures, and complications. The primary outcome was PEP. The registry included 12,718 ERCP procedures performed on patients without a history of previous ERCP. The risk of PEP when using the rendezvous technique compared with those who were cannulated by conventional means was reduced from 3.6 to 2.2% (odds ratio (OR) 0.5, 95% confidence interval 0.2-0.9, P=0.02). Although a significant reduction there are overall relatively few cases with PEP and the calculated numbers needed to treat to avoid one case of PEP is as high as 71. Other factors associated with increased risk of PEP were young age, prolonged procedure time, and elective ERCP. Rendezvous bile duct cannulation during ERCP reduces the risk of PEP from 3.6 to 2.2% compared with conventional biliary cannulation.

DART: A simulation code for charged particle beams

International Nuclear Information System (INIS)

White, R.C.; Barr, W.L.; Moir, R.W.

1989-01-01

This paper presents a recently modified version of the 2-D code, DART, which can simulate the behavior of a beam of charged particles whose trajectories are determined by electric and magnetic fields. This code was originally used to design laboratory-scale and full-scale beam direct converters. Since then, its utility has been expanded to allow more general applications. The simulation includes space charge, secondary electrons, and the ionization of neutral gas. A beam can contain up to nine superimposed beamlets of different energy and species. The calculation of energy conversion efficiency and the method of specifying the electrode geometry are described. Basic procedures for using the code are given, and sample input and output fields are shown. 7 refs., 18 figs

Endo-laparoscopic rendezvous approach for pericardia with gastric posterior wall of gastrointestinal stromal tumor: analysis of 52 consecutive cases.

Science.gov (United States)

Ding, Po; Zhao, Yongjie

2014-12-01

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tract and most frequently developed in the stomach, and surgical therapy is limited on removal of the tumor lesion. The aim of this study was to investigate the clinical values of endo-laparoscopic rendezvous approach for pericardial GISTs within gastric posterior wall. Surgical outcome and clinical data of 52 patients with pericardial GISTs within gastric posterior wall treated at Tianjin Peoples' Hospital from January 2004 to October 2013 were analyzed. Endo-laparoscopic rendezvous approach was used as an operative procedure for tumor resection ranged from 10 to 50 mm. Endoscopic ultrasound, computed tomography and microscopic findings all certified the gastric spindle type GIST locating in the submucosa to muscle proper. Endo-laparoscopic rendezvous approach was attempted in 52 patients (male/female: 31/21) with median age of 51 years (25-71 years). The median operating time was 80 min (range: 40-120 min) and median intra-operative blood loss was 26 ml (range: 10-50 ml). The median hospital stay was 5 days (range: 4-6 days), while the median tumor size was 25 mm (range: 7-50 mm). All operative margins were clear. There were no recurrences or metastases of all patients in a median follow-up of 24 months (range: 6-36 months). Endo-laparoscopic rendezvous approach is considered to represent the next revolution in surgery. The new technique is reliable and effective in clinical application, due to the advantages of accurate and quick localization for pericardial GIST within gastric posterior wall.

A modified Rendezvous ERCP technique in duodenal diverticulum.

Science.gov (United States)

Odabasi, Mehmet; Yildiz, Mehmet Kamil; Abuoglu, Haci Hasan; Eris, Cengiz; Ozkan, Erkan; Gunay, Emre; Aktekin, Ali; Muftuoglu, Ma Tolga

2013-11-16

To postoperative endoscopic retrograde cholangiopancreatography (ERCP) failure, we describe a modified Rendezvous technique for an ERCP in patients operated on for common bile duct stone (CBDS) having a T-tube with retained CBDSs. Five cases operated on for CBDSs and having retained stones with a T-tube were referred from other hospitals located in or around Istanbul city to the ERCP unit at the Haydarpasa Numune Education and Research Hospital. Under sedation anesthesia, a sterile guide-wire was inserted via the T-tube into the common bile duct (CBD) then to the papilla. A guide-wire was held by a loop snare and removed through the mouth. The guide-wire was inserted into the sphincterotome via the duodenoscope from the tip to the handle. The duodenoscope was inserted down to the duodenum with a sphincterotome and a guide-wire in the working channel. With the guidance of a guide-wire, the ERCP and sphincterotomy were successfully performed, the guide-wire was removed from the T-tube, the stones were removed and the CBD was reexamined for retained stones by contrast. An ERCP can be used either preoperatively or postoperatively. Although the success rate in an isolated ERCP treatment ranges from up to 87%-97%, 5%-10% of the patients require two or more ERCP treatments. If a secondary ERCP fails, the clinicians must be ready for a laparoscopic or open exploration. A duodenal diverticulum is one of the most common failures in an ERCP, especially in patients with an intradiverticular papilla. For this small group of patients, an antegrade cannulation via a T-tube can improve the success rate up to nearly 100%. The modified Rendezvous technique is a very easy method and increases the success of postoperative ERCP, especially in patients with large duodenal diverticula and with intradiverticular papilla.

CNEA/ANL collaboration program to develop an optimized version of DART validation and assessment by means of U3 Six and U3 O8-Al dispersed CNEA mini plate irradiation behavior

International Nuclear Information System (INIS)

Solis, Diego; Taboada, Horacio; Rest, Jeffrey

1998-01-01

The DART code is based upon a thermochemical model that can predict swelling, recrystallization, fuel-meat interdiffusion and other issues related with MTR dispersed FE behavior under irradiation. As a part of a common effort to develop an optimized version of DART, a comparison between DART predictions and CNEA miniplates irradiation experimental data was made. The irradiation took place during 1981-82 for U3O8 miniplates and 1985-86 for U 3 Si x at Oak Ridge Research Reactor. (author)

Exploring germplasm diversity to understand the domestication process in Cicer spp. using SNP and DArT markers.

Directory of Open Access Journals (Sweden)

Manish Roorkiwal

Full Text Available To estimate genetic diversity within and between 10 interfertile Cicer species (94 genotypes from the primary, secondary and tertiary gene pool, we analysed 5,257 DArT markers and 651 KASPar SNP markers. Based on successful allele calling in the tertiary gene pool, 2,763 DArT and 624 SNP markers that are polymorphic between genotypes from the gene pools were analyzed further. STRUCTURE analyses were consistent with 3 cultivated populations, representing kabuli, desi and pea-shaped seed types, with substantial admixture among these groups, while two wild populations were observed using DArT markers. AMOVA was used to partition variance among hierarchical sets of landraces and wild species at both the geographical and species level, with 61% of the variation found between species, and 39% within species. Molecular variance among the wild species was high (39% compared to the variation present in cultivated material (10%. Observed heterozygosity was higher in wild species than the cultivated species for each linkage group. Our results support the Fertile Crescent both as the center of domestication and diversification of chickpea. The collection used in the present study covers all the three regions of historical chickpea cultivation, with the highest diversity in the Fertile Crescent region. Shared alleles between different gene pools suggest the possibility of gene flow among these species or incomplete lineage sorting and could indicate complicated patterns of divergence and fusion of wild chickpea taxa in the past.

Pancreatic duct drainage using EUS-guided rendezvous technique for stenotic pancreaticojejunostomy.

Science.gov (United States)

Takikawa, Tetsuya; Kanno, Atsushi; Masamune, Atsushi; Hamada, Shin; Nakano, Eriko; Miura, Shin; Ariga, Hiroyuki; Unno, Jun; Kume, Kiyoshi; Kikuta, Kazuhiro; Hirota, Morihisa; Yoshida, Hiroshi; Katayose, Yu; Unno, Michiaki; Shimosegawa, Tooru

2013-08-21

The patient was a 30-year-old female who had undergone excision of the extrahepatic bile duct and Roux-en-Y hepaticojejunostomy for congenital biliary dilatation at the age of 7. Thereafter, she suffered from recurrent acute pancreatitis due to pancreaticobiliary maljunction and received subtotal stomach-preserving pancreaticoduodenectomy. She developed a pancreatic fistula and an intra-abdominal abscess after the operation. These complications were improved by percutaneous abscess drainage and antibiotic therapy. However, upper abdominal discomfort and the elevation of serum pancreatic enzymes persisted due to stenosis from the pancreaticojejunostomy. Because we could not accomplish dilation of the stenosis by endoscopic retrograde cholangiopancreatography, we tried an endoscopic ultrasonography (EUS) guided rendezvous technique for pancreatic duct drainage. After transgastric puncture of the pancreatic duct using an EUS-fine needle aspiration needle, the guidewire was inserted into the pancreatic duct and finally reached to the jejunum through the stenotic anastomosis. We changed the echoendoscope to an oblique-viewing endoscope, then grasped the guidewire and withdrew it through the scope. The stenosis of the pancreaticojejunostomy was dilated up to 4 mm, and a pancreatic stent was put in place. Though the pancreatic stent was removed after three months, the patient remained symptom-free. Pancreatic duct drainage using an EUS-guided rendezvous technique was useful for the treatment of a stenotic pancreaticojejunostomy after pancreaticoduodenectomy.

Genetic Diversity of Turf-Type Tall Fescue Using Diversity Arrays Technology

Czech Academy of Sciences Publication Activity Database

Baird, J. H.; Kopecký, David; Lukaszewski, A.J.; Green, R. J.; Bartoš, Jan; Doležel, Jaroslav

2012-01-01

Roč. 52, č. 1 (2012), s. 408-412 ISSN 0011-183X Institutional research plan: CEZ:AV0Z50380511 Keywords : Festuca arundinacea * Diversity Arrays Technology (DArT) * Low genetic polymorphism Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.513, year: 2012

How Recommender Systems in Technology-Enhanced Learning depend on Context

NARCIS (Netherlands)

Drachsler, Hendrik; Manouselis, Nikos

2009-01-01

Drachsler, H., & Manouselis, N. (2009). How Recommender Systems in Technology-Enhanced Learning depend on Context. Presentation given at the 1st workshop on Context-aware Recommender Systems for Learning at the Alpine Rendez-Vous 2009. November, 30 - December, 3, 2009, Garmisch-Patenkirchen,

Sharper and faster "nano darts" kill more bacteria: a study of antibacterial activity of individually dispersed pristine single-walled carbon nanotube.

Science.gov (United States)

Liu, Shaobin; Wei, Li; Hao, Lin; Fang, Ning; Chang, Matthew Wook; Xu, Rong; Yang, Yanhui; Chen, Yuan

2009-12-22

To further our understanding on the antibacterial activity of single-walled carbon nanotubes (SWCNTs), high purity SWCNTs with average diameter of 0.83 nm and (7,5) chirality as dominate (n,m) structure were dispersed in a biocompatible surfactant solution. Ultraviolet-visible-near-infrared radiation absorption spectroscopy was employed to monitor the aggregation of SWCNTs. The results demonstrated that individually dispersed SWCNTs were more toxic than SWCNT aggregates toward bacteria (gram-negative Escherichia coli, Pseudomonas aeruginosa, and gram-positive Staphylococcus aureus, Bacillus subtilis). Individually dispersed SWCNTs can be visualized as numerous moving "nano darts" in the solution, constantly attacking the bacteria; thereby, degrading the bacterial cell integrity and causing the cell death. Controlled experimental results suggested that inhibiting cell growth and oxidative stress were not the major causes responsible for the death of cells. Furthermore, the detrimental effects of Co metal residues (up to 1 mug/mL) on SWCNT samples can be ruled out. Atomic force microscope study conducted in suspension proved that the death rates of bacteria were strongly correlated with their mechanical properties; soft cells were more vulnerable to SWCNT piercing. The antibacterial activity of SWCNTs can be remarkably improved by enhancing the SWCNT physical puncture on bacteria in the following ways: (1) dispersing SWCNTs individually to sharpen the nano darts; (2) increasing SWCNT concentration to raise the population density of nano darts; and (3) elevating the shaking speed of incubation to speed up the nano darts. This study elucidated several factors controlling the antibacterial activity of pristine SWCNTs and it provided an insight in developing strategies that can maximize the SWCNT application potentials while minimizing the health and environment risks.

Assessment of Ploidy and Genome Constitution of Some Musa balbisiana Cultivars using DArT Markers

Czech Academy of Sciences Publication Activity Database

Sales, E. K.; Butardo, N. G.; Paniagua, H. G.; Jansen, H.; Doležel, Jaroslav

2011-01-01

Roč. 36, č. 1 (2011), s. 11-18 ISSN 0115-463X Institutional research plan: CEZ:AV0Z50380511 Keywords : DArT * genome * Musa balbisiana Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.075, year: 2011 http://home.ueb.cas.cz/publikace/2011_Sales_PHILIPPINE_JOURNAL_OF_CROP_SCIENCE_11.pdf

A Summary of the Rendezvous, Proximity Operations, Docking, and Undocking (RPODU) Lessons Learned from the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) Demonstration System Mission

Science.gov (United States)

Dennehy, Cornelius J.; Carpenter, James R.

2011-01-01

The Guidance, Navigation, and Control (GN&C) Technical Discipline Team (TDT) sponsored Dr. J. Russell Carpenter, a Navigation and Rendezvous Subject Matter Expert (SME) from NASA's Goddard Space Flight Center (GSFC), to provide support to the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) rendezvous and docking flight test that was conducted in 2007. When that DARPA OE mission was completed, Mr. Neil Dennehy, NASA Technical Fellow for GN&C, requested Dr. Carpenter document his findings (lessons learned) and recommendations for future rendezvous missions resulting from his OE support experience. This report captures lessons specifically from anomalies that occurred during one of OE's unmated operations.

Butorphanol, azaperone, and medetomidine anesthesia in free-ranging white-tailed deer (Odocoileus virginianus) using radiotransmitter darts.

Science.gov (United States)

Siegal-Willott, Jessica; Citino, Scott B; Wade, Scotty; Elder, Laura; Hayek, Lee-Ann C; Lance, William R

2009-04-01

Fourteen free-ranging white-tailed deer (Odocoileus virginianus) were successfully anesthetized for a total of 15 anesthetic events using a combination of butorphanol (mean+/-SD, 0.58+/-0.1 mg/kg), azaperone (0.37+/-0.06 mg/kg), and medetomidine (0.19+/-0.03 mg/kg) (BAM) administered by radiotelemetry darts from hunting blinds between November 2006 and May 2007. Mean time to locate deer (mean+/-SD, 17. 3+/-7 min), to recumbency (21.4+/-5 min), to initiation of data acquisition (27.5+/-8 min), total down time (37+/-6 min), and average distance run (161+/-82 m) were recorded. Physiologic monitoring was done every 5 min for a total of 20 min. Arterial blood gases were collected every 10 min. Mild to moderate hypoxemia and mildly depressed ventilation occurred in some animals. Muscle relaxation and plane of anesthesia were adequate for completion of all procedures; two deer were administered intravenous butorphanol supplementation to achieve light anesthesia (mean+/-SD, 0.19 mg/kg; 0.12 mg/kg). Recovery following intramuscular administration of naltrexone (1.34+/-0.42 mg/kg; 2x butorphanol dose) and atipamezole (0.93+/-0.14 mg/kg; 5x medetomidine dose) was rapid, smooth, and complete. Mean+/-SD recovery time was 4.5+/-1.5 min. Overall efficacy of the Pneu-Dart radiotelemetry system was 65%. Negative attributes of this protocol included long induction time and dart failure. No known mortalities occurred as a result of the study. This drug combination provided safe, reliable, short-term anesthesia of free-ranging white-tailed deer. Further evaluation for use in field procedures in other cervids is warranted.

Coherent Doppler lidar for automated space vehicle rendezvous, stationkeeping and capture

Science.gov (United States)

Bilbro, James A.

1991-01-01

The inherent spatial resolution of laser radar makes ladar or lidar an attractive candidate for Automated Rendezvous and Capture application. Previous applications were based on incoherent lidar techniques, requiring retro-reflectors on the target vehicle. Technology improvements (reduced size, no cryogenic cooling requirement) have greatly enhanced the construction of coherent lidar systems. Coherent lidar permits the acquisition of non-cooperative targets at ranges that are limited by the detection capability rather than by the signal-to-noise ratio (SNR) requirements. The sensor can provide translational state information (range, velocity, and angle) by direct measurement and, when used with any array detector, also can provide attitude information by Doppler imaging techniques. Identification of the target is accomplished by scanning with a high pulse repetition frequency (dependent on the SNR). The system performance is independent of range and should not be constrained by sun angle. An initial effort to characterize a multi-element detection system has resulted in a system that is expected to work to a minimum range of 1 meter. The system size, weight and power requirements are dependent on the operating range; 10 km range requires a diameter of 3 centimeters with overall size at 3 x 3 x 15 to 30 cm, while 100 km range requires a 30 cm diameter.

The Properties of SIRT, TVM, and DART for 3D imaging of nanocomposite thin-films and sections

NARCIS (Netherlands)

Chen, D.; Goris, B.; Bleichrodt, F.; Mezerji, H.H.; Bals, S.; Batenburg, K.J.; With, de G.; Friedrich, H.

2014-01-01

In electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and applying

Rendezvous Protocols and Dynamic Frequency Hopping Interference Design for Anti-Jamming Satellite Communication

Science.gov (United States)

2013-11-25

previously considered this proactive approach to combat unintentional, persistent (non- reactive) interference . In this project, we plan on extending our...channel” (or code ) by chance, through public knowledge of the underlying protocol semantics , or by compromising one of the network devices. An alternative...AFRL-RV-PS- AFRL-RV-PS- TR-2013-0142 TR-2013-0142 RENDEZVOUS PROTOCOLS AND DYNAMIC FREQUENCY HOPPING INTERFERENCE DESIGN FOR ANTI-JAMMING

Shaping of parabolic cylindrical membrane reflectors for the Dart Precision Test Bed

Science.gov (United States)

Morgan, R.; Agnes, Gregory S.; Dragovan, M.; Barber, D.; Marcin, M.; White, C.; Dooley, J.; Hatheway, A.

2004-01-01

The DART is a new telescope architecture consisting of a single aperture formed from two cylindrical parabolic reflectors. The system is ideally suited to using tensioned membranes for the reflective surfaces, owing to the zero Gaussian curvature of a cylindrical parabola. In this paper, we present experimental measurements for shaping the membranes by using curved boundary elements to achieve coarse shaping, and a pair of precision rails shaped by moments and forces at the ends, and lightly pushed into the surface, to provide fine shape control.

Ability Beliefs, Task Value, and Performance as a Function of Race in a Dart-Throwing Task

Science.gov (United States)

Gao, Zan; Kosma, Maria; Harrison, Louis, Jr.

2009-01-01

This study examines differences in self-efficacy, expectancy-related beliefs, task value, and performance in a dart-throwing task as a function of race among diverse college students using the expectancy-value model and self-efficacy theory. It also examines the predictive contributions of these beliefs on task performance within each racial…

Evaluation of Recommender Systems for Technology-Enhanced Learning: Challenges and Possible Solutions

NARCIS (Netherlands)

Sandy, Heleau; Drachsler, Hendrik; Gillet, Dennis

2009-01-01

Heleou, S., Drachsler, H., & Gillet, D. (2009). Evaluation of Recommender Systems for Technology-Enhanced Learning: Challenges and Possible Solutions. 1st workshop on Context-aware Recommender Systems for Learning at the Alpine Rendez-Vous. November, 30-December, 3, 2009, Garmisch-Patenkirchen,

Space Shuttle Guidance, Navigation, and Rendezvous Knowledge Capture Reports. Revision 1

Science.gov (United States)

Goodman, John L.

2011-01-01

This document is a catalog and readers guide to lessons learned, experience, and technical history reports, as well as compilation volumes prepared by United Space Alliance personnel for the NASA/Johnson Space Center (JSC) Flight Dynamics Division.1 It is intended to make it easier for future generations of engineers to locate knowledge capture documentation from the Shuttle Program. The first chapter covers observations on documentation quality and research challenges encountered during the Space Shuttle and Orion programs. The second chapter covers the knowledge capture approach used to create many of the reports covered in this document. These chapters are intended to provide future flight programs with insight that could be used to formulate knowledge capture and management strategies. The following chapters contain descriptions of each knowledge capture report. The majority of the reports concern the Space Shuttle. Three are included that were written in support of the Orion Program. Most of the reports were written from the years 2001 to 2011. Lessons learned reports concern primarily the shuttle Global Positioning System (GPS) upgrade and the knowledge capture process. Experience reports on navigation and rendezvous provide examples of how challenges were overcome and how best practices were identified and applied. Some reports are of a more technical history nature covering navigation and rendezvous. They provide an overview of mission activities and the evolution of operations concepts and trajectory design. The lessons learned, experience, and history reports would be considered secondary sources by historians and archivists.

Rapid qualitative analysis of 2 flavonoids, rutin and silybin, in medical pills by direct analysis in real-time mass spectrometry (DART-MS) combined with in situ derivatization.

Science.gov (United States)

Nagy, Tibor; Kuki, Ákos; Nagy, Lajos; Zsuga, Miklós; Kéki, Sándor

2018-03-01

Direct analysis in real-time mass spectrometry (DART-MS) with in situ silylation was used for the rapid analysis of the flavonoids silybin ((2R,3R)-3,5,7-trihydroxy-2-[3-(4-hydroxy-3-methoxyphenyl)-2-hydroxymethyl-2,3-dihydrobenzo[1,4]dioxin-6-yl]chroman-4-one) and rutin (quercetin-3-O-rutinoside). Three different derivatization reagents, hexamethyldisilazane/trimethylchlorosilane/pyridine (HMDS/TMCS/pyridine), N,O-bis(trimethylsilyl)acetamide/trimethylchlorosilane/N-trimethylsilyimidazole (BSA/TMCS/TMSI), and N,O-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA/TMCS), were applied. Silybin and rutin were detected with various degrees of silylation, and the formation of dimers with pyridine and imidazole was also observed. HMDS/TMCS/pyridine was the best choice for the DART-MS analysis of silybin, and BSA/TMCS/TMSI was the most effective for the detection of rutin. The effects of the DART source temperature on desorption, ionization, in-source fragmentation, dimer formation, and hydrolysis of the trimethylsilyl groups were also studied. In addition, the collision-induced dissociation properties of the derivatized silybin and rutin were explored. With our in situ silylation method, the derivatized bioactive compounds in intact medical pills could also be detected by DART-MS. Copyright © 2017 John Wiley & Sons, Ltd.

Guidance and navigation for rendezvous with an uncooperative target

Science.gov (United States)

Telaar, J.; Schlaile, C.; Sommer, J.

2018-06-01

This paper presents a guidance strategy for a rendezvous with an uncooperative target. In the applied design reference mission, a spiral approach is commanded ensuring a collision-free relative orbit due to e/i-vector separation. The dimensions of the relative orbit are successively reduced by Δv commands which at the same time improve the observability of the relative state. The navigation is based on line-of-sight measurements. The relative state is estimated by an extended Kalman filter (EKF). The performance of this guidance and navigation strategy is demonstrated by extensive Monte Carlo simulations taking into account all major uncertainties like measurement errors, Δv execution errors, and differential drag.

A Survey of LIDAR Technology and Its Use in Spacecraft Relative Navigation

Science.gov (United States)

Christian, John A.; Cryan, Scott P.

2013-01-01

This paper provides a survey of modern LIght Detection And Ranging (LIDAR) sensors from a perspective of how they can be used for spacecraft relative navigation. In addition to LIDAR technology commonly used in space applications today (e.g. scanning, flash), this paper reviews emerging LIDAR technologies gaining traction in other non-aerospace fields. The discussion will include an overview of sensor operating principles and specific pros/cons for each type of LIDAR. This paper provides a comprehensive review of LIDAR technology as applied specifically to spacecraft relative navigation. HE problem of orbital rendezvous and docking has been a consistent challenge for complex space missions since before the Gemini 8 spacecraft performed the first successful on-orbit docking of two spacecraft in 1966. Over the years, a great deal of effort has been devoted to advancing technology associated with all aspects of the rendezvous, proximity operations, and docking (RPOD) flight phase. After years of perfecting the art of crewed rendezvous with the Gemini, Apollo, and Space Shuttle programs, NASA began investigating the problem of autonomous rendezvous and docking (AR&D) to support a host of different mission applications. Some of these applications include autonomous resupply of the International Space Station (ISS), robotic servicing/refueling of existing orbital assets, and on-orbit assembly.1 The push towards a robust AR&D capability has led to an intensified interest in a number of different sensors capable of providing insight into the relative state of two spacecraft. The present work focuses on exploring the state-of-the-art in one of these sensors - LIght Detection And Ranging (LIDAR) sensors. It should be noted that the military community frequently uses the acronym LADAR (LAser Detection And Ranging) to refer to what this paper calls LIDARs. A LIDAR is an active remote sensing device that is typically used in space applications to obtain the range to one or more

The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections.

Science.gov (United States)

Chen, Delei; Goris, Bart; Bleichrodt, Folkert; Mezerji, Hamed Heidari; Bals, Sara; Batenburg, Kees Joost; de With, Gijsbertus; Friedrich, Heiner

2014-12-01

In electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and applying different angular sampling schemes. A well-defined realistic model is generated, which consists of tubular domains within a matrix having slab-geometry. Subsequently, the electron tomography workflow is simulated from calculated tilt-series over experimental effects to reconstruction. In comparison with the model, the fidelity of each reconstruction method is evaluated qualitatively and quantitatively based on global and local edge profiles and resolvable distance between particles. Results show that the performance of all reconstruction methods declines with the total electron dose. Overall, SIRT algorithm is the most stable method and insensitive to changes in angular sampling. TVM algorithm yields significantly sharper edges in the reconstruction, but the edge positions are strongly influenced by the tilt scheme and the tubular objects become thinned. The DART algorithm markedly suppresses the elongation artifacts along the beam direction and moreover segments the reconstruction which can be considered a significant advantage for quantification. Finally, no advantage of TVM and DART to deal better with fewer projections was observed. Copyright © 2014 Elsevier B.V. All rights reserved.

The endoscopic ultrasonography-guided rendezvous technique for biliary cannulation: a technical review.

Science.gov (United States)

Isayama, Hiroyuki; Nakai, Yousuke; Kawakubo, Kazumichi; Kawakami, Hiroshi; Itoi, Takao; Yamamoto, Natsuyo; Kogure, Hirofumi; Koike, Kazuhiko

2013-04-01

Steady progress is being made in endoscopic biliary intervention, especially endoscopic ultrasonography (EUS)-guided procedures. The EUS-guided rendezvous technique (EUS-RV) is a salvage method for failed selective biliary cannulation. The overall success rate of EUS-RV in 247 cases from seven published articles was 74 % and the incidence of complications was 11 %. The main cause of failed rendezvous cannulation was difficulty passing a biliary stricture or papilla due to poor guidewire (GW) manipulation. A recent large study found a 98.3 % success rate and superiority to precutting. This report suggested using a hydrophilic guidewire. Major complications were bleeding (0.8 %), bile leakage (1.2 %), peritonitis (0.4 %), pneumoperitoneum (0.2 %), and pancreatitis (1.6 %). The approach routes for EUS-RV were transgastric, transduodenal short position, and transduodenal long position. The appropriate route for each patient should be used. GW selection for EUS-RV is critical, and a hydrophilic GW might be the most useful. The catheter can be inserted through the papilla alongside or over the wire. Alongside cannulation is convenient, but difficult. The problem with the over-the-wire technique is withdrawal of the GW in the accessory channel. EUS-RV is effective and safe, but is not established. The efficacy should be confirmed in a prospective comparative trial, and the necessary specialist equipment should be developed.

直接实时分析质谱超速分析在药品监管中的应用%Ultra Speed Direct Analysis in Real Time Mass Spectrometry(DART-MS)for Drug Administration

Institute of Scientific and Technical Information of China (English)

王铁松; 张喆; 赵明; 车宝泉; 高青; 王威

2011-01-01

目的 建立直接实时分析质谱(DART-MS)超速分析方法应用于药品监管检验工作.方法 DART-MS将实时直接分析离子源(DART)与离子阱质谱联用,离子源放电电压为4kV,载气为氦气,流速为6L· min(-1),温度为400℃.在不进行样品色谱分离的前提下,直接分析被测物质或其溶液.结果 DART-MS与液质联用相比检定效率提高近50倍,对西地那非、米诺地尔等已知物质可在20s内检测出,对未知衍生物可在4 min内完成其多级质谱研究,对传统液相色谱法难以分析的辅料如混合脂肪酸甘油酯等也能准确分析.结论 DART-MS样品处理简单,方法准确速度快,能广泛应用于非法添加、药物污染、制剂辅料成分的快速检定,开创了药品监管的新方法,能有效提高对突发安全事件的反应能力.%OBJECTIVE To establish an ultra speed direct analysis in real time (DART)-ion trap mass spectrometry method for screening of shampoo and herbal remedies for the presence of illegal additives. METHODS The DART temperature was 400 ℃, the helium flow rate was 6 L · min-1 and the mass cone voltage was 4 kV. The solution was directly screened using a 12-DIP sampler. RESULTS The speed of DART-MS was 50 times faster than that of LC-MS for identifying the additives including minoxidil,sildenafil,and mixed glycerides. CONCLUSION Each additive studied was rapidly identified within 20 seconds by DART-MS/MS, sugggesting this technique can be used for drug administration. However,its sensitivity and quantitation still requires further study and improvement.

Ray-tracing 3D dust radiative transfer with DART-Ray: code upgrade and public release

Science.gov (United States)

Natale, Giovanni; Popescu, Cristina C.; Tuffs, Richard J.; Clarke, Adam J.; Debattista, Victor P.; Fischera, Jörg; Pasetto, Stefano; Rushton, Mark; Thirlwall, Jordan J.

2017-11-01

We present an extensively updated version of the purely ray-tracing 3D dust radiation transfer code DART-Ray. The new version includes five major upgrades: 1) a series of optimizations for the ray-angular density and the scattered radiation source function; 2) the implementation of several data and task parallelizations using hybrid MPI+OpenMP schemes; 3) the inclusion of dust self-heating; 4) the ability to produce surface brightness maps for observers within the models in HEALPix format; 5) the possibility to set the expected numerical accuracy already at the start of the calculation. We tested the updated code with benchmark models where the dust self-heating is not negligible. Furthermore, we performed a study of the extent of the source influence volumes, using galaxy models, which are critical in determining the efficiency of the DART-Ray algorithm. The new code is publicly available, documented for both users and developers, and accompanied by several programmes to create input grids for different model geometries and to import the results of N-body and SPH simulations. These programmes can be easily adapted to different input geometries, and for different dust models or stellar emission libraries.

Effects of Relaxing and Arousing Music during Imagery Training on Dart-Throwing Performance, Physiological Arousal Indices, and Competitive State Anxiety.

Science.gov (United States)

Kuan, Garry; Morris, Tony; Kueh, Yee Cheng; Terry, Peter C

2018-01-01

Music that is carefully selected to match the requirements of activities and the characteristics of individuals has been shown to produce significant impacts on performance enhancement (Priest et al., 2004). There is also evidence that music can enhance imagery (Grocke and Wigram, 2007), although few studies have investigated the effects of music on imagery in the context of sport skills. In the present study, the effects of relaxing and arousing music during imagery on dart-throwing performance, physiological arousal indices, and competitive state anxiety, were investigated among 63 novice dart throwers. Participants had moderate-to-high imagery ability and were randomly assigned to unfamiliar relaxing music (URM), unfamiliar arousing music (UAM), or no music (NM) groups. Performance was assessed by 40 dart throws at a concentric circles dartboard before and after 12 imagery sessions over 4 weeks. Measures of galvanic skin response (GSR), peripheral temperature (PT), and heart rate (HR) were taken during imagery sessions 1 and 12, and the Competitive State Anxiety Inventory-2 Revised (CSAI-2R) was administered prior to the pre- and post-intervention performance task. Dart-throwing gain scores were significantly higher for URM than for UAM and NM, with no significant difference between UAM and NM (URM = 37.24 ± 5.66, UAM = 17.57 ± 5.30, and NM = 13.19 ± 6.14, F 2,62 = 5.03, p = 0.01, η 2 = 0.14). GSR, PT, and HR reflected lower arousal for URM than for UAM or NM. Significant decreases in somatic anxiety were evident for URM and UAM but not NM. Significant decreases in cognitive anxiety were evident for URM and NM but not UAM. Significant increases in self-confidence were evident for URM but not UAM or NM. Performance improved in all three conditions but URM was associated with the largest performance gain, the lowest physiological indices of arousal, and the most positive CSAI-2R profiles. Listening to relaxing music during imagery may have benefits for

Effects of Relaxing and Arousing Music during Imagery Training on Dart-Throwing Performance, Physiological Arousal Indices, and Competitive State Anxiety

Directory of Open Access Journals (Sweden)

Garry Kuan

2018-02-01

Full Text Available Music that is carefully selected to match the requirements of activities and the characteristics of individuals has been shown to produce significant impacts on performance enhancement (Priest et al., 2004. There is also evidence that music can enhance imagery (Grocke and Wigram, 2007, although few studies have investigated the effects of music on imagery in the context of sport skills. In the present study, the effects of relaxing and arousing music during imagery on dart-throwing performance, physiological arousal indices, and competitive state anxiety, were investigated among 63 novice dart throwers. Participants had moderate-to-high imagery ability and were randomly assigned to unfamiliar relaxing music (URM, unfamiliar arousing music (UAM, or no music (NM groups. Performance was assessed by 40 dart throws at a concentric circles dartboard before and after 12 imagery sessions over 4 weeks. Measures of galvanic skin response (GSR, peripheral temperature (PT, and heart rate (HR were taken during imagery sessions 1 and 12, and the Competitive State Anxiety Inventory-2 Revised (CSAI-2R was administered prior to the pre- and post-intervention performance task. Dart-throwing gain scores were significantly higher for URM than for UAM and NM, with no significant difference between UAM and NM (URM = 37.24 ± 5.66, UAM = 17.57 ± 5.30, and NM = 13.19 ± 6.14, F2,62 = 5.03, p = 0.01, η2 = 0.14. GSR, PT, and HR reflected lower arousal for URM than for UAM or NM. Significant decreases in somatic anxiety were evident for URM and UAM but not NM. Significant decreases in cognitive anxiety were evident for URM and NM but not UAM. Significant increases in self-confidence were evident for URM but not UAM or NM. Performance improved in all three conditions but URM was associated with the largest performance gain, the lowest physiological indices of arousal, and the most positive CSAI-2R profiles. Listening to relaxing music during imagery may have benefits for

Endoscopic ultrasonography-guided pancreatic duct access: techniques and literature review of pancreatography, transmural drainage and rendezvous techniques.

Science.gov (United States)

Itoi, Takao; Kasuya, Kazuhiko; Sofuni, Atsushi; Itokawa, Fumihide; Kurihara, Toshio; Yasuda, Ichiro; Nakai, Yousuke; Isayama, Hiroyuki; Moriyasu, Fuminori

2013-05-01

Endoscopic ultrasonography-guided (EUS)-guided pancreatic interventions have gained increasing attention. Here we review EUS-guided pancreatic duct (PD) access techniques and outcomes. EUS-guided PD intervention is divided into two types, antegrade and rendezvous techniques, following EUS-guided pancreatography. In the antegrade technique, pancreaticoenterostomy is carried out by stent placement between the PD and the stomach, duodenum, or jejunum. Transenteric antegrade PD stenting is conducted by stent placement, advancing anteriorly into the PD through the pancreatic tract. The rendezvous technique is carried out by using a guidewire through the papilla or anastomotic site for retrograde stent insertion. In terms of EUS-guided PD stenting, 11 case reports totaling 75 patients (35 normal anatomy, 40 altered anatomy) have been published. The technical success rate was greater than 70%. Early adverse events, including severe hematoma and severe pancreatitis,occurred in seven (63.6%) of 11 reports. Regarding the rendezvous technique, 12 case reports totaling 52 patients (22 normal anatomy, 30 altered anatomy) have been published. The technical success rate ranged from 25% to 100%. It was 48% in one report that involved more than 20 cases. Once stents were placed, all patients became free of symptoms. Early mild adverse events occurred in four (36.4%) of 11 reports. In conclusion, although it can be risky because of possible serious or even fatal adverse events, including pancreatic juice leakage, perforation and severe acute pancreatitis, EUS-PD access seems to be promising for treating symptomatic pancreatic diseases caused by PD stricture and pancreaticoenterostomy stricture. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

Simulation of Satellite, Airborne and Terrestrial LiDAR with DART (I):Waveform Simulation with Quasi-Monte Carlo Ray Tracing

Science.gov (United States)

Gastellu-Etchegorry, Jean-Philippe; Yin, Tiangang; Lauret, Nicolas; Grau, Eloi; Rubio, Jeremy; Cook, Bruce D.; Morton, Douglas C.; Sun, Guoqing

2016-01-01

Light Detection And Ranging (LiDAR) provides unique data on the 3-D structure of atmosphere constituents and the Earth's surface. Simulating LiDAR returns for different laser technologies and Earth scenes is fundamental for evaluating and interpreting signal and noise in LiDAR data. Different types of models are capable of simulating LiDAR waveforms of Earth surfaces. Semi-empirical and geometric models can be imprecise because they rely on simplified simulations of Earth surfaces and light interaction mechanisms. On the other hand, Monte Carlo ray tracing (MCRT) models are potentially accurate but require long computational time. Here, we present a new LiDAR waveform simulation tool that is based on the introduction of a quasi-Monte Carlo ray tracing approach in the Discrete Anisotropic Radiative Transfer (DART) model. Two new approaches, the so-called "box method" and "Ray Carlo method", are implemented to provide robust and accurate simulations of LiDAR waveforms for any landscape, atmosphere and LiDAR sensor configuration (view direction, footprint size, pulse characteristics, etc.). The box method accelerates the selection of the scattering direction of a photon in the presence of scatterers with non-invertible phase function. The Ray Carlo method brings traditional ray-tracking into MCRT simulation, which makes computational time independent of LiDAR field of view (FOV) and reception solid angle. Both methods are fast enough for simulating multi-pulse acquisition. Sensitivity studies with various landscapes and atmosphere constituents are presented, and the simulated LiDAR signals compare favorably with their associated reflectance images and Laser Vegetation Imaging Sensor (LVIS) waveforms. The LiDAR module is fully integrated into DART, enabling more detailed simulations of LiDAR sensitivity to specific scene elements (e.g., atmospheric aerosols, leaf area, branches, or topography) and sensor configuration for airborne or satellite LiDAR sensors.

Estimation of Spruce Needle-Leaf Chlorophyll Content Based on DART and PARAS Canopy Reflectance Models

Czech Academy of Sciences Publication Activity Database

Yáñez-Rausell, L.; Malenovský, Z.; Rautiainen, M.; Clevers, J G P W.; Lukeš, Petr; Hanuš, Jan; Schaepman, M. E.

2015-01-01

Roč. 8, č. 4 (2015), s. 1534-1544 ISSN 1939-1404 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Chlorophyll a plus b estimation * CHRIS-PROBA * coniferous forest * continuum removal * discrete anisotropic radiative transfer model (DART) * needle-leaf * Norway spruce * optical indices * PARAS * PROSPECT * radiative transfer * recollision probability Subject RIV: EH - Ecology, Behaviour Impact factor: 2.145, year: 2015

Visual Control for Multirobot Organized Rendezvous.

Science.gov (United States)

Lopez-Nicolas, G; Aranda, M; Mezouar, Y; Sagues, C

2012-08-01

This paper addresses the problem of visual control of a set of mobile robots. In our framework, the perception system consists of an uncalibrated flying camera performing an unknown general motion. The robots are assumed to undergo planar motion considering nonholonomic constraints. The goal of the control task is to drive the multirobot system to a desired rendezvous configuration relying solely on visual information given by the flying camera. The desired multirobot configuration is defined with an image of the set of robots in that configuration without any additional information. We propose a homography-based framework relying on the homography induced by the multirobot system that gives a desired homography to be used to define the reference target, and a new image-based control law that drives the robots to the desired configuration by imposing a rigidity constraint. This paper extends our previous work, and the main contributions are that the motion constraints on the flying camera are removed, the control law is improved by reducing the number of required steps, the stability of the new control law is proved, and real experiments are provided to validate the proposal.

DART MS based chemical profiling for therapeutic potential of Piper betle landraces.

Science.gov (United States)

Bajpai, Vikas; Pandey, Renu; Negi, Mahendra Pal Singh; Kumar, Nikhil; Kumar, Brijesh

2012-12-01

Piper betle Linn. leaves are traditionally used as a folk medicine in India and other Asiatic countries. Twenty-one P. betle landraces were analyzed using a Direct Analysis in Real Time (DART) mass spectral technique and evaluated on the basis of molecules detected in the leaves. Clustering of landraces based on three well known biologically active phenols (m/z 151,165,193) showed two broad groups with high and low phenol contents suggesting differences in their therapeutic potential. Findings of this study could be useful in rapid screening of the landraces for determining their medicinal potential and optimum utilization of the bioresource.

Radiation effects in the Si-PIN detector on the Near Earth Asteroid Rendezvous mission

CERN Document Server

Starr, R; Evans, L G; Floyd, S R; McClanahan, T P; Trombka, J I; Goldsten, J O; Maurer, R H; McNutt, R L; Roth, D R

1999-01-01

A Si-PIN photodiode is being used as a solar X-ray monitor on the X-ray/gamma-ray spectrometer experiment which is flying on the Near Earth Asteroid Rendezvous spacecraft. Since its launch in February 1996 this photodiode has experienced several brief failures. These anomalies and other performance characteristics will be described. Efforts to reproduce these failures in ground tests with flight spare equipment will also be discussed.

Generic DART-MS platform for monitoring the on-demand continuous-flow production of pharmaceuticals: Advancing the quantitative protocol for caffeates in microfluidic biocatalysis.

Science.gov (United States)

Xu, Yan; Zhang, Dong-Yang; Meng, Xiang-Yun; Liu, Xi; Sheng, Sheng; Wu, Guo-Hua; Wang, Jun; Wu, Fu-An

2017-04-15

Today, continuous processing is regarded as an effective on-demand production technique of pharmaceuticals. Homemade microreactors packed with immobilized lipase under continuous-flow conditions were first applied to tailor the production of high-value caffeic acid phenethyl ester (CAPE) from methyl caffeate (MC) and 2-phenylethanol (PE) in cyclohexane via transesterification; however, this method is challenging due to the lack of a rapid platform for monitoring caffeates in microfluidic biocatalysis. The reactants were directly analyzed using Direct Analysis in Real Time Mass Spectrometry (DART-MS), and the corresponding ionization parameters were investigated. Special ions produced from MC (parent ion m/z 192.87 and product ion m/z 133.44) and CAPE (parent ion m/z 282.93 and product ion m/z 178.87) were determined using DART-MS 2 in the negative ion mode. The peak areas of the select reaction monitoring (SRM) signals were calculated to develop the standard curves for quantitative analyses of the concentration. Reasonable linear regression equations of MC and CAPE were obtained in the range of 3.125-50.000mg/L, with linear coefficients (R 2 ) of 0.9515 and 0.9973, limits of detection (LOD) of 0.005 and 0.003mg/L, limits of quantification (LOQ) of 0.02 and 0.01mg/L, and recovery ranges of 92.50-97.11% and 90.11-97.60%, respectively. The results using DART-MS 2 were in good agreement with those using conventional High-Performance Liquid Chromatography with a UV detector (HPLC-UV) and were successfully applied to monitor the kinetics constants and mass transfer coefficients in a continuous-flow packed bed microreactor. Thus, the DART-MS 2 method is an efficient tool for analyzing caffeates in microfluidic biocatalysis with limited sample preparation and short operating time. Copyright © 2017 Elsevier B.V. All rights reserved.

NEP for a Kuiper Belt Object rendezvous mission

International Nuclear Information System (INIS)

Lipinski, Ronald J.; Lenard, Roger X.; Wright, Steven A.; Houts, Michael G.; Patton, Bruce; Poston, David I.

2000-01-01

Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOs with a diameter greater than 100 km. KBOs are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOs. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total DV of 46 km/s. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=0). Alternatively, the system could be placed into a 700-km earth orbit with more propellant, yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All

NEP for a Kuiper Belt Object Rendezvous Mission

International Nuclear Information System (INIS)

HOUTS, MICHAEL G.; LENARD, ROGER X.; LIPINSKI, RONALD J.; PATTON, BRUCE; POSTON, DAVID I.; WRIGHT, STEVEN A.

1999-01-01

Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOS with a diameter greater than 100 km. KBOS are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOS. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total ΔV of 46 krnk. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=O). Alternatively, the system could be placed into a 700-km earth orbit with more propellant,yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All

Endoscopic Sphincterotomy Using the Rendezvous Technique for Choledocholithiasis during Laparoscopic Cholecystectomy: A Case Report.

Science.gov (United States)

Tanaka, Takayuki; Haraguchi, Masashi; Tokai, Hirotaka; Ito, Shinichiro; Kitajima, Masachika; Ohno, Tsuyoshi; Onizuka, Shinya; Inoue, Keiji; Motoyoshi, Yasuhide; Kuroki, Tamotsu; Kanemastu, Takashi; Eguchi, Susumu

2014-05-01

A 50-year-old male was examined at another hospital for fever, general fatigue and slight abdominal pain. He was treated with antibiotics and observed. However, his symptoms did not lessen, and laboratory tests revealed liver dysfunction, jaundice and an increased inflammatory response. He was then admitted to our hospital and underwent an abdominal computed tomography scan and magnetic resonance cholangiopancreatography (MRCP), which revealed common bile duct (CBD) stones. He was diagnosed with mild acute cholangitis. As the same time, he was admitted to our hospital and an emergency endoscopic retrograde cholangiopancreatography was performed. Vater papilla opening in the third portion of the duodenum and presence of a peripapillary duodenal diverticulum made it difficult to perform cannulation of the CBD. In addition, MRCP revealed that the CBD was extremely narrow (diameter 5 mm). We therefore performed laparoscopic cholecystectomy and endoscopic sphincterotomy using the rendezvous technique for choledocholithiasis simultaneously rather than laparoscopic CBD exploration. After the operation, the patient was discharged with no complications. Although the rendezvous technique has not been very commonly used because several experts in the technique and a large operating room are required, this technique is a very attractive and effective approach for treating choledocholithiasis, for which endoscopic treatment is difficult.

Endoscopic Sphincterotomy Using the Rendezvous Technique for Choledocholithiasis during Laparoscopic Cholecystectomy: A Case Report

Directory of Open Access Journals (Sweden)

Takayuki Tanaka

2014-08-01

Full Text Available A 50-year-old male was examined at another hospital for fever, general fatigue and slight abdominal pain. He was treated with antibiotics and observed. However, his symptoms did not lessen, and laboratory tests revealed liver dysfunction, jaundice and an increased inflammatory response. He was then admitted to our hospital and underwent an abdominal computed tomography scan and magnetic resonance cholangiopancreatography (MRCP, which revealed common bile duct (CBD stones. He was diagnosed with mild acute cholangitis. As the same time, he was admitted to our hospital and an emergency endoscopic retrograde cholangiopancreatography was performed. Vater papilla opening in the third portion of the duodenum and presence of a peripapillary duodenal diverticulum made it difficult to perform cannulation of the CBD. In addition, MRCP revealed that the CBD was extremely narrow (diameter 5 mm. We therefore performed laparoscopic cholecystectomy and endoscopic sphincterotomy using the rendezvous technique for choledocholithiasis simultaneously rather than laparoscopic CBD exploration. After the operation, the patient was discharged with no complications. Although the rendezvous technique has not been very commonly used because several experts in the technique and a large operating room are required, this technique is a very attractive and effective approach for treating choledocholithiasis, for which endoscopic treatment is difficult.

A 10-year study of rendezvous intraoperative endoscopic retrograde cholangiography during cholecystectomy and the risk of post-ERCP pancreatitis.

Science.gov (United States)

Noel, Rozh; Enochsson, Lars; Swahn, Fredrik; Löhr, Matthias; Nilsson, Magnus; Permert, Johan; Arnelo, Urban

2013-07-01

Rendezvous intraoperative endoscopic retrograde cholangiography (RV-IOERC), also called guidewire-facilitated IOERC, is one of the single-stage options available for managing common bile duct stones (CBDS) during laparoscopic cholecystectomy. The objective of this study is to investigate procedure-related complications in IOERC patients and stone clearance. All patients who underwent IOERC between January 2000 and December 2009 were identified from the local registry of Karolinska University Hospital in Huddinge. Medical charts and ERC reports were studied, and descriptive statistics were obtained. Outcomes were procedure-related complications, especially post-ERCP pancreatitis (PEP), stone clearance, and mortality. 307 patients were identified. In 264 of the patients, the rendezvous cannulation technique was successful (86 %); in the remaining 43 patients, conventional cannulation technique was necessary. In total, PEP occurred in seven patients (2.28 %). One of the PEP patients was in the rendezvous cannulated group (0.37 %), whereas six patients developed PEP in the nonrendezvous group (13.95 %, p < 0.001). The primary stone clearance rate was 88.27 % (271/307). There was no mortality within 90 days in the series. IOERC with RV cannulation technique for management of CBDS during laparoscopic cholecystectomy has a low PEP rate and a high stone clearance rate, making it a safe and feasible method for removing CBDS. However, the technique requires logistics to perform IOERC in the operating theater. The present data suggest that IOERC with RV cannulation is superior to conventional cannulation with respect to risk of PEP.

Endoscopic ultrasound rendezvous for bile duct access using a transduodenal approach: cumulative experience at a single center. A case series.

Science.gov (United States)

Kim, Y S; Gupta, K; Mallery, S; Li, R; Kinney, T; Freeman, M L

2010-06-01

Endoscopic ultrasound (EUS)-assisted biliary access is utilized when conventional endoscopic retrograde cholangiopancreatography (ERCP) fails. We report a 10-year experience utilizing a transduodenal EUS rendezvous via a transpapillary route without dilation of the transduodenal tract, followed by immediate ERCP access. Patients included all EUS-guided rendezvous procedures for biliary access that were performed following ERCP failure. EUS-assisted bile duct puncture was performed via a transduodenal approach and a guide wire was advanced through the papilla without any dilation or bougienage of the tract; ERCP was performed immediately afterwards. EUS-assisted biliary rendezvous was attempted in 15 patients (mean age 66 +/- 18.2 years; malignant = 10, benign = 5). Mean diameter of measured bile ducts was 14.3 +/- 5.17 mm (range 4-23 mm). The reasons for initial ERCP failure were tumor infiltration or edema (n = 9), intradiverticular papilla (n = 2), pre-existing duodenal stent (n = 1), and anatomic anomalies (n = 3). Successful EUS-guided bile duct puncture and wire passage were achieved in all 15 patients (100 %), with drainage being successful in 12 / 15 (80 %). Failures occurred in three patients due to inability to traverse the biliary stricture (n = 2) or dissection of a choledochocele with the guide wire (n = 1); all were subsequently drained via percutaneous methods. Stents placed were metallic in eight patients and plastic in four. Complications consisted of moderate pancreatitis after a difficult ERCP attempt in one patient, and bacteremia after percutaneous biliary drainage in another. There were no instances of perforation, extraluminal air or fluid collections. EUS-assisted biliary drainage utilizing a transduodenal rendezvous approach demonstated a high success rate without any complications directly attributable to the EUS access. Advantages over percutaneous biliary and other methods of EUS biliary access include performance under the same

Image-guided ureteral reconstruction using rendezvous technique for complex ureteric transection after gunshot injuries.

Science.gov (United States)

Arabi, Mohammad; Mat'hami, Abdulaziz; Said, Mohammad T; Bulbul, Muhammad; Haddad, Maurice; Al-Kutoubi, Aghiad

2016-01-01

Management of complex ureteric transection poses a significant clinical challenge, particularly after gunshot injuries due to marked distortion of anatomy and associated tissue loss. We report two cases of total ureteric transection due to gunshot injury successfully repaired using fluoroscopy-guided rendezvous procedure and double J stent placement. This minimally invasive approach may offer a safe and effective technique to repair complete ureteral transection and obviate the need for complex surgical procedures.

Rapid process development of chromatographic process using direct analysis in real time mass spectrometry as a process analytical technology tool.

Science.gov (United States)

Yan, Binjun; Chen, Teng; Xu, Zhilin; Qu, Haibin

2014-06-01

The concept of quality by design (QbD) is widely applied in the process development of pharmaceuticals. However, the additional cost and time have caused some resistance about QbD implementation. To show a possible solution, this work proposed a rapid process development method, which used direct analysis in real time mass spectrometry (DART-MS) as a process analytical technology (PAT) tool for studying the chromatographic process of Ginkgo biloba L., as an example. The breakthrough curves were fast determined by DART-MS at-line. A high correlation coefficient of 0.9520 was found between the concentrations of ginkgolide A determined by DART-MS and HPLC. Based on the PAT tool, the impacts of process parameters on the adsorption capacity were discovered rapidly, which showed a decreased adsorption capacity with the increase of the flow rate. This work has shown the feasibility and advantages of integrating PAT into QbD implementation for rapid process development. Copyright © 2014 Elsevier B.V. All rights reserved.

Directional radiative transfer by SCOPE, SLC and DART using laser scan derived structural forest parameters

Science.gov (United States)

Timmermans, Joris; Gastellu-Etchegorry, Jean Philippe; van der Tol, Christiaan; Verhoef, Wout; Vekerdy, Zoltan; Su, Zhongbo

2017-04-01

Accurate estimation of the radiative transfer (RT) over vegetation is the corner stone of agricultural and hydrological remote sensing applications. Present remote sensing sensors mostly use traditional optical, thermal and microwave observations. However with these traditional observations characterization of the light efficiency and photosynthetic rate can only be accomplished indirectly. A promising new method of observing these processes is by using the fluorescent emitted radiation. This approach was recently highlighted due to the selection of the FLEX sensor as a future Earth Explorer by the European Space agency (ESA). Several modelling activities have been undertaken to better understand the technical feasibilities of this sensor. Within these studies, the SCOPE model has been chosen as the baseline algorithm. This model combines a detailed RT description of the canopy, using a discrete version of the SAIL model, with a description of photosynthetic processes (by use of the Farquhar/Ball-Berry model). Consequently, this model is capable of simulating simultaneously the biophysical processes and jointly the fluorescent, optical and thermal RT. The SAIL model however is a 1D RT model and consequently provides higher uncertainties with increasing vegetation structures. The main objective of this research is to investigate the limitations of the RT model component of the SCOPE model over complex canopies. In particular the aim of this research is to evaluate the validity for increasingly structural complex canopies', on the bidirectional reflectance distribution functions (BRDF) of these canopies. This was accomplished by evaluating the simulated outgoing radiation from SCOPE/SAIL against simulations of the DART 3D RT model. In total nine different scenarios were simulated with the DART RTM with increasing structural complexity, ranging from the simple 'Plot' scenario to the highly complex 'Multiple Crown' scenario. The canopy parameters are retrieved from a

Endo-laparoscopic rendezvous approach for pericardia with gastric posterior wall of gastrointestinal stromal tumor: Analysis of 52 consecutive cases

Directory of Open Access Journals (Sweden)

Po Ding

2014-01-01

Conclusions: Endo-laparoscopic rendezvous approach is considered to represent the next revolution in surgery. The new technique is reliable and effective in clinical application, due to the advantages of accurate and quick localization for pericardial GIST within gastric posterior wall.

Effects of distribution density and cell dimension of 3D vegetation model on canopy NDVI simulation base on DART

Science.gov (United States)

Tao, Zhu; Shi, Runhe; Zeng, Yuyan; Gao, Wei

2017-09-01

The 3D model is an important part of simulated remote sensing for earth observation. Regarding the small-scale spatial extent of DART software, both the details of the model itself and the number of models of the distribution have an important impact on the scene canopy Normalized Difference Vegetation Index (NDVI).Taking the phragmitesaustralis in the Yangtze Estuary as an example, this paper studied the effect of the P.australias model on the canopy NDVI, based on the previous studies of the model precision, mainly from the cell dimension of the DART software and the density distribution of the P.australias model in the scene, As well as the choice of the density of the P.australiass model under the cost of computer running time in the actual simulation. The DART Cell dimensions and the density of the scene model were set by using the optimal precision model from the existing research results. The simulation results of NDVI with different model densities under different cell dimensions were analyzed by error analysis. By studying the relationship between relative error, absolute error and time costs, we have mastered the density selection method of P.australias model in the simulation of small-scale spatial scale scene. Experiments showed that the number of P.australias in the simulated scene need not be the same as those in the real environment due to the difference between the 3D model and the real scenarios. The best simulation results could be obtained by keeping the density ratio of about 40 trees per square meter, simultaneously, of the visual effects.

Autonomous rendezvous and docking operations of unmanned expendable cargo transfer vehicles (e.g. Centaur) with Space Station Freedom

Science.gov (United States)

Emmet, Brian R.

1991-01-01

This paper describes the results of the feasibility study using Centaur or other CTV's to deliver payloads to the Space Station Freedom (SSF). During this study was examined the requirements upon unmanned cargo transfer stages (including Centaur) for phasing, rendezvous, proximity operations and docking/berthing (capture).

The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections

NARCIS (Netherlands)

D. Chen; B. Goris (Bart); F. Bleichrodt (Folkert); H.H. Mezerji; S. Bals (Sara); K.J. Batenburg (Joost); G. de With; H. Friedrich

2014-01-01

htmlabstractIn electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and

Robust control for constant thrust rendezvous under thrust failure

Directory of Open Access Journals (Sweden)

Qi Yongqiang

2015-04-01

Full Text Available A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapunov function subject to linear matrix inequalities. Secondly, the robust controllers satisfying the requirements can be designed by solving this optimization problem. Then, a new algorithm of constant thrust fitting is proposed through the impulse compensation and the fuel consumption under the theoretical continuous thrust and the actual constant thrust is calculated and compared by using the method proposed in this paper. Finally, the proposed method having the advantage of saving fuel is proved and the actual constant thrust switch control laws are obtained through the isochronous interpolation method, meanwhile, an illustrative example is provided to show the effectiveness of the proposed control design method.

Legitimizing Political Science or Splitting the Discipline? Reflections on DA-RT and the Policy-making Role of a Professional Association

NARCIS (Netherlands)

Schwartz-Shea, Peregrine; Yanow, Dvora

2016-01-01

We have been invited by Politics & Gender's editors to review the origins and current standing of the Data Access and Research Transparency (DA-RT) policy, an effort initiated by the eponymous American Political Science Association (APSA) Ad Hoc Committee and led primarily by Colin Elman,

The rendezvous technique involving insertion of a guidewire in a percutaneous transhepatic gallbladder drainage tube for biliary access in a case of difficult biliary cannulation.

Science.gov (United States)

Sunada, Fumiko; Morimoto, Naoki; Tsukui, Mamiko; Kurata, Hidekazu

2017-05-01

Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic method and treatment approach for biliary diseases. However, biliary cannulation can be difficult in some cases. We performed ERCP in a 97-year-old woman with abdominal pain resulting from acute cholangitis caused by choledocholithiasis and observed difficult biliary cannulation. Eventually, the patient was successfully treated with the rendezvous technique. We could not cannulate the biliary duct during ERCP twice. Therefore, we placed a percutaneous transhepatic gallbladder drainage (PTGBD) tube without intrahepatic dilation. The rendezvous technique was performed using the PTGBD tube. The patient did not experience pancreatitis or perforation.

Genetic Diversity and Population Structure of Tetraploid Wheats (Triticum turgidum L. Estimated by SSR, DArT and Pedigree Data.

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Giovanni Laidò

Full Text Available Levels of genetic diversity and population genetic structure of a collection of 230 accessions of seven tetraploid Triticum turgidum L. subspecies were investigated using six morphological, nine seed storage protein loci, 26 SSRs and 970 DArT markers. The genetic diversity of the morphological traits and seed storage proteins was always lower in the durum wheat compared to the wild and domesticated emmer. Using Bayesian clustering (K = 2, both of the sets of molecular markers distinguished the durum wheat cultivars from the other tetraploid subspecies, and two distinct subgroups were detected within the durum wheat subspecies, which is in agreement with their origin and year of release. The genetic diversity of morphological traits and seed storage proteins was always lower in the improved durum cultivars registered after 1990, than in the intermediate and older ones. This marked effect on diversity was not observed for molecular markers, where there was only a weak reduction. At K >2, the SSR markers showed a greater degree of resolution than for DArT, with their identification of a greater number of groups within each subspecies. Analysis of DArT marker differentiation between the wheat subspecies indicated outlier loci that are potentially linked to genes controlling some important agronomic traits. Among the 211 loci identified under selection, 109 markers were recently mapped, and some of these markers were clustered into specific regions on chromosome arms 2BL, 3BS and 4AL, where several genes/quantitative trait loci (QTLs are involved in the domestication of tetraploid wheats, such as the tenacious glumes (Tg and brittle rachis (Br characteristics. On the basis of these results, it can be assumed that the population structure of the tetraploid wheat collection partially reflects the evolutionary history of Triticum turgidum L. subspecies and the genetic potential of landraces and wild accessions for the detection of unexplored alleles.

3D Reconstruction of a Fluvial Sediment Slug from Source to Sink: reach-scale modeling of the Dart River, NZ

Science.gov (United States)

Brasington, J.; Cook, S.; Cox, S.; James, J.; Lehane, N.; McColl, S. T.; Quincey, D. J.; Williams, R. D.

2014-12-01

Following heavy rainfall on 4/1/14, a debris flow at Slip Stream (44.59 S 168.34 E) introduced >106 m3 of sediment to the Dart River valley floor in NZ Southern Alps. Runout over an existing fan dammed the Dart River causing a sudden drop in discharge downstream. This broad dam was breached quickly; however the temporary loss of conveyance impounded a 3 km lake with a volume of 6 x 106 m3 and depths that exceed 10 m. Quantifying the impact of this large sediment pulse on the Dart River is urgently needed to assess potential sedimentation downstream and will also provide an ideal vehicle to test theories of bed wave migration in large, extensively braided rivers. Recent advances in geomatics offer the opportunity to study these impacts directly through the production of high-resolution DEMs. These 3D snapshots can then be compared through time to quantify the morphodynamic response of the channel as it adjusts to the change in sediment supply. In this study we describe the methods and results of a novel survey strategy designed to capture of the complex morphology of the Dart River along a remote 40 km reach, from the upstream landslide source to its distal sediment sink in Lake Wakatipu. The scale of this system presents major logistical and methodological challenges, and hitherto would have conventionally be addressed with airborne laser scanning, bringing with it significant deployment constraints and costs. By contrast, we present sub-metre 3D reconstructions of the system (Figure 1), derived from highly redundant aerial photography shot with a non-metric camera from a helicopter survey that extended over an 80 km2 area. Structure-from-Motion photogrammetry was used to solve simultaneously camera position, pose and derive a 3D point cloud based on over 4000 images. Reconstructions were found to exhibit significant systematic error resulting from the implicit estimation of the internal camera orientation parameters, and we show how these effects can be minimized

Orthotic intervention incorporating the dart-thrower's motion as part of conservative management guidelines for treatment of scapholunate injury.

Science.gov (United States)

Anderson, Hamish; Hoy, Greg

2016-01-01

Case series. This paper describes conservative guidelines for the management of scapho-lunate interosseous ligament (SLIL) injury including fabrication of an orthosis that restricts active wrist movement to the dart-throwers (DTM) plane. The dart throwers' orthosis (DTO) was designed as a response to biomechanical studies suggesting that restraining motion to the DTM would off-load a deficient SLIL. After six weeks of wearing the DTO, the 5 patients in this case series initiated an exercise program that incorporated wrist proprioceptive training and specific muscle strengthening. The DTO was designed to incorporate controlled movement in order to better integrate the secondary wrist stabilizers in wrists that had a deficient SLIL. The orthosis and the exercise program harnessed proprioceptive influences using active motion within the DTM plane, and stimulated mechanoreceptors so as to enhance stability. All patients demonstrated improvement in subjective and objective outcomes including self-reported pain and function. Orthotic intervention that controls motion within the DTM, combined with an appropriate proprioceptive rehabilitation program, may provide a viable conservative treatment option for patients with a similar clinical presentation. 4. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Spatial localisation of curcumin and rapid screening of the chemical compositions of turmeric rhizomes (Curcuma longa Linn.) using Direct Analysis in Real Time-Mass Spectrometry (DART-MS).

Science.gov (United States)

Rahman, A F M Motiur; Angawi, Rihab F; Kadi, Adnan A

2015-04-15

Curcumin is a potent antioxidant agent having versatile biological activities is present in turmeric rhizomes (Curcuma longa Linn.). Powder of turmeric rhizomes is consumes as curry spicy worldwide, especially in Asia. In this study, we demonstrate that, bioactive curcumin and its analog demethoxycurcumin are chiefly concentrated in the pith rather than the other parts of the turmeric rhizomes and it was discovered using modern atmospheric ionisation source 'Direct Analysis in Real Time' (DART) connected with an Ion Trap Mass Spectrometry. In addition, all the major components present in turmeric rhizomes were detected in positive and/or in negative ion mode using DART. Copyright © 2014 Elsevier Ltd. All rights reserved.

Endoscopic ultrasonography-guided rendezvous technique.

Science.gov (United States)

Tsuchiya, Takayoshi; Itoi, Takao; Sofuni, Atsushi; Tonozuka, Ryosuke; Mukai, Shuntaro

2016-04-01

Endoscopic retrograde cholangiopancreatography (ERCP) requires deep biliary cannulation. When deep biliary cannulation is failed, the endoscopic ultrasonography rendezvous technique (EUS-RV) is a useful salvage method. From the previous 15 articles that included 382 EUS-RV cases, the overall success rate of EUS-RV is 81 % with a complication rate of 10 %. In EUS-RV, the bile duct is punctured under EUS guidance and a guidewire is advanced into the duodenum via the papilla. The EUS scope is then switched to a duodenoscope and inserted into the bile duct over the guidewire exiting the papilla, or the guidewire is grasped with forceps and passed through the working channel; the catheter can then be inserted through the papilla over the wire. There are three puncture routes for EUS-RV: transgastric puncture of the intrahepatic bile duct (IHBD), transduodenal puncture of the extrahepatic bile duct (EHBD) via the proximal duodenum (D1), and transduodenal puncture of the EHBD via the second portion of the duodenum (D2). The puncture route for each patient should be selected based on the patient condition. GW selection for EUS-RV is critical, a hydrophilic GW is useful for this procedure. Although EUS-RV is now performed relatively routinely in a few high-volume centers, procedure standardization and the development of exclusive devices for EUS-RV are still underway. The development of exclusive devices for EUS-RV and prospective comparative studies with other salvage methods are needed to truly evaluate the procedure's usefulness and safety.

La formation continue des usagers : évaluation qualitative des rendez-vous d'évaluation post-permis pour les conducteurs novices. Thème 11. Rapport final

OpenAIRE

CHATENET, F; TORRES, S; GAUTHIER, P; PERVANCHON, M

2001-01-01

Rapport final de convention DSCR/INRETS. Le présent rapport fait état de l'évaluation qualitative des rendez-vous d'évaluation (RVE) pour les conducteurs novices, le volet des rendez-vous de perfectionnement (RVP) pour les conducteurs expérimentés sera abordé ultérieurement dans le cadre d'une convention DSCR/INRETS. La première partie développe les problématiques et les objectifs poursuivis par cette étude ainsi que la méthodologie qui a été utilisée. Les trois autres parties présentent les...

The Dart estuary, Devon, UK: a case study of chemical dynamics and pollutant mobility

Directory of Open Access Journals (Sweden)

2007-01-01

Full Text Available Water, sediments and gill and digestive gland tissues of adult common shore crab (Carcinus maenas, collected at Noss Marina, Sandquay (Britannia Royal Naval College, the Dartmouth Pier, Warfleet Cove and Sugary Cove in the Dart estuary, Devon, UK, were analysed for major, minor and trace elements in spring 2004. Total acid-available measurements analysed included the truly dissolved component and acid-available sediments. Trace metal concentrations are associated largely with particulate and micro-particulate/colloidal phases, the latter being able to pass through standard filter papers. Wide ranges of chemical concentrations were found in the water, sediments and tissues at all the locations. In the water column, 48% of the variance is linked to the sea-salt component (Cl, Na, K, Ca, Mg, B, Li and Sr and the sediment-associated acid-available fractions are linked to Fe-rich lithogenous materials (Ba, Co, Cu, Fe, Mn, V and Zn. In the sediments, trace elements of Cd, Co, Cr, Fe, Pb, Mn, Ni and V are correlated with the sea salts and associated with the fraction of fine sediments within the total sediment. In the gills and the digestive gland tissues of crabs, high concentrations of Al, Cu and Fe are found and there are correlations between acid-available trace metals of Cu, Cr, Fe, Mn, Ni, Sr and Zn. The relationships between trace metal contaminants, their site-specific concentrations, their temporal and spatial variability and the effects of human activities, such as moorland/agriculture with historic mining and recreational activities in the lower Dart estuary, are discussed.

Subject-Specific Carpal Ligament Elongation in Extreme Positions, Grip, and the Dart Thrower's Motion

Science.gov (United States)

Rainbow, Michael J.; Kamal, Robin N.; Moore, Douglas C.; Akelman, Edward; Wolfe, Scott W.; Crisco, Joseph J.

2015-01-01

This study examined whether the radiocarpal and dorsal capsular ligaments limit end-range wrist motion or remain strained during midrange wrist motion. Fibers of these ligaments were modeled in the wrists of 12 subjects over multiple wrist positions that reflect high demand tasks and the dart thrower's motion. We found that many of the volar and dorsal ligaments were within 5% of their maximum length throughout the range of wrist motion. Our finding of wrist ligament recruitment during midrange and end-range wrist motion helps to explain the complex but remarkably similar intersubject patterns of carpal motion. PMID:26367853

Usefulness of the 'Rendezvous' Technique in Living Related Right Liver Donors with Postoperative Biliary Leakage from Bile Duct Anastomosis

International Nuclear Information System (INIS)

Miraglia, R.; Traina, M.; Maruzzelli, L.; Caruso, S.; Di Pisa, M.; Gruttadauria, S.; Luca, A.; Gridelli, B.

2008-01-01

This is a report on two cases of large bile leak following right hepatectomy performed for living related liver transplantation, originating from the stump of the ligated right bile duct, and treated with the placement of large percutaneous biliary catheters through a combined percutaneous transhepatic and endoscopic approach (rendezvous technique).

Transluminal recanalization of chronic total occlusion of radial artery using rendezvous technique: a case report and literature review.

Science.gov (United States)

Arabi, Mohammad; Ahmed, Ishtiaq; Qattan, Nabeel

2014-01-01

Although endovascular management of lower extremity peripheral arterial disease (PAD) is well studied, little information exists regarding endovascular treatment of critical upper limb ischemia. We report a case of transluminal recanalization of right radial artery chronic total occlusion (CTO) using rendezvous technique in a patient with critical hand ischemia and dry gangrene of the right index finger.

System and Method for Automated Rendezvous, Docking and Capture of Autonomous Underwater Vehicles

Science.gov (United States)

Stone, William C. (Inventor); Clark, Evan (Inventor); Richmond, Kristof (Inventor); Paulus, Jeremy (Inventor); Kapit, Jason (Inventor); Scully, Mark (Inventor); Kimball, Peter (Inventor)

2018-01-01

A system for automated rendezvous, docking, and capture of autonomous underwater vehicles at the conclusion of a mission comprising of comprised of a docking rod having lighted, pulsating (in both frequency and light intensity) series of LED light strips thereon, with the LEDs at a known spacing, and the autonomous underwater vehicle specially designed to detect and capture the docking rod and then be lifted structurally by a spherical end strop about which the vehicle can be pivoted and hoisted up (e.g., onto a ship). The method of recovery allows for very routine and reliable automated recovery of an unmanned underwater asset.

Reflecting on the Postgraduate Experience: Teaching Research Methods and Statistics: Review of the DART-P Sponsored Workshop at PsyPAG 2013

Science.gov (United States)

Jackson, Emma J.; Davies, Emma. L.

2014-01-01

Following the success of last year's teaching and career development workshop, this year's DART-P sponsored workshop at the Psychology Postgraduate Affairs Group (PsyPAG) Annual Conference held at Lancaster University focused on postgraduate's experiences of teaching research methods. This article provides a review of the invited speakers…

Efficacy of the Laparoendoscopic "Rendezvous" to Treat Cholecystocholedocholithiasis in 210 Consecutive Patients: A Single Center Experience.

Science.gov (United States)

La Greca, Gaetano; Pesce, Antonio; Vitale, Marco; Mannino, Maurizio; Di Marco, Federica; Di Blasi, Michele; Lombardo, Rosario; Puleo, Stefano; Russello, Domenico; Latteri, Saverio

2017-08-01

The simultaneous laparoendoscopic "rendezvous" (LERV) represents an alternative to sequential or totally laparoscopic approaches for patients affected by cholecystocholedocholithiasis. The aim of this study was to analyze the results in a large series of 210 consecutive patients. From 2002 to 2016 all patients affected by cholecystocholedocholithiasis were treated with a standardized "tailored" LERV. The relevant technical features of the procedure were recorded. An analysis of feasibility, effectiveness in stone clearance, and safety was performed. Among 214 patients with common bile duct stones, 210 were treated with LERV and 4 with open rendezvous approach. Intraoperative cholangiography confirmed common bile duct stones in 179 patients (85.2%) or sludge in 18 (8.5%) and in 98.9% stone clearance was obtained endoscopically. Endoscopic papilla cannulation was feasible in 161 patients (76.7%), whereas in 49 (23.3%) a transcystic guidewire was needed. The overall LERV feasibility was 96.6%. The conversion rate to open surgery was 3.3%. Minor morbidity was observed in 1.9% of cases, mortality in 0.47%, and the mean hospital stay was 4.3 days. These results confirm the high effectiveness of LERV. This approach to treat cholecystocholedocholithiasis should be preferred and therefore implemented where a strong collaboration between surgeons and endoscopists is possible.

Overview: Solar Electric Propulsion Concept Designs for SEP Technology Demonstration Mission

Science.gov (United States)

Mcguire, Melissa L.; Hack, Kurt J.; Manzella, David; Herman, Daniel

2014-01-01

JPC presentation of the Concept designs for NASA Solar Electric Propulsion Technology Demonstration mission paper. Multiple Solar Electric Propulsion Technology Demonstration Missions were developed to assess vehicle performance and estimated mission cost. Concepts ranged from a 10,000 kg spacecraft capable of delivering 4000 kg of payload to one of the Earth Moon Lagrange points in support of future human-crewed outposts to a 180 kg spacecraft capable of performing an asteroid rendezvous mission after launched to a geostationary transfer orbit as a secondary payload.

The NASA Engineering and Safety Center (NESC) GN and C Technical Discipline Team (TDT): Its Purpose, Practices and Experiences

Science.gov (United States)

Dennehy, Cornelius J.

2008-01-01

This paper will briefly define the vision, mission, and purpose of the NESC organization. The role of the GN&C TDT will then be described in detail along with an overview of how this team operates and engages in its objective engineering and safety assessments of critical NASA projects. This paper will then describe key issues and findings from several of the recent GN&C-related independent assessments and consultations performed and/or supported by the NESC GN&C TDT. Among the examples of the GN&C TDT s work that will be addressed in this paper are the following: the Space Shuttle Orbiter Repair Maneuver (ORM) assessment, the ISS CMG failure root cause assessment, the Demonstration of Autonomous Rendezvous Technologies (DART) spacecraft mishap consultation, the Phoenix Mars lander thruster-based controllability consultation, the NASA in-house Crew Exploration Vehicle (CEV) Smart Buyer assessment and the assessment of key engineering considerations for the Design, Development, Test & Evaluation (DDT&E) of robust and reliable GN&C systems for human-rated spacecraft.

Transluminal Recanalization of Chronic Total Occlusion of Radial Artery Using Rendezvous Technique: A Case Report and Literature Review

Directory of Open Access Journals (Sweden)

Mohammad Arabi

2014-01-01

Full Text Available Although endovascular management of lower extremity peripheral arterial disease (PAD is well studied, little information exists regarding endovascular treatment of critical upper limb ischemia. We report a case of transluminal recanalization of right radial artery chronic total occlusion (CTO using rendezvous technique in a patient with critical hand ischemia and dry gangrene of the right index finger.

Assist-as-needed robotic trainer based on reinforcement learning and its application to dart-throwing.

Science.gov (United States)

Obayashi, Chihiro; Tamei, Tomoya; Shibata, Tomohiro

2014-05-01

This paper proposes a novel robotic trainer for motor skill learning. It is user-adaptive inspired by the assist-as-needed principle well known in the field of physical therapy. Most previous studies in the field of the robotic assistance of motor skill learning have used predetermined desired trajectories, and it has not been examined intensively whether these trajectories were optimal for each user. Furthermore, the guidance hypothesis states that humans tend to rely too much on external assistive feedback, resulting in interference with the internal feedback necessary for motor skill learning. A few studies have proposed a system that adjusts its assistive strength according to the user's performance in order to prevent the user from relying too much on the robotic assistance. There are, however, problems in these studies, in that a physical model of the user's motor system is required, which is inherently difficult to construct. In this paper, we propose a framework for a robotic trainer that is user-adaptive and that neither requires a specific desired trajectory nor a physical model of the user's motor system, and we achieve this using model-free reinforcement learning. We chose dart-throwing as an example motor-learning task as it is one of the simplest throwing tasks, and its performance can easily be and quantitatively measured. Training experiments with novices, aiming at maximizing the score with the darts and minimizing the physical robotic assistance, demonstrate the feasibility and plausibility of the proposed framework. Copyright © 2014 Elsevier Ltd. All rights reserved.

DarT: The embryo test with the Zebrafish Danio rerio--a general model in ecotoxicology and toxicology.

Science.gov (United States)

Nagel, Roland

2002-01-01

The acute fish test is an animal test whose ecotoxicological relevance is worthy of discussion. The primary aim of protection in ecotoxicology is the population and not the individual. Furthermore the concentration of pollutants in the environment is normally not in the lethal range. Therefore the acute fish test covers solely the situation after chemical spills. Nevertheless, acute fish toxicity data still belong to the base set used for the assessment of chemicals. The embryo test with the zebrafish Danio rerio (DarT) is recommended as a substitute for the acute fish test. For validation an international laboratory comparison test was carried out. A summary of the results is presented in this paper. Based on the promising results of testing chemicals and waste water the test design was validated by the DIN-working group "7.6 Fischei-Test". A normed test guideline for testing waste water with fish is available. The test duration is short (48 h) and within the test different toxicological endpoints can be examined. Endpoints from the embryo test are suitable for QSAR-studies. Besides the use in ecotoxicology the introduction as a toxicological model was investigated. Disturbance of pigmentation and effects on the frequency of heart-beat were examined. A further important application is testing of teratogenic chemicals. Based on the results DarT could be a screening test within preclinical studies.

Coherent Doppler lidar for automated space vehicle, rendezvous, station-keeping and capture

Science.gov (United States)

Dunkin, James A.

1991-01-01

Recent advances in eye-safe, short wavelength solid-state lasers offer real potential for the development of compact, reliable, light-weight, efficient coherent lidar. Laser diode pumping of these devices has been demonstrated, thereby eliminating the need for flash lamp pumping, which has been a major drawback to the use of these lasers in space based applications. Also these lasers now have the frequency stability required to make them useful in coherent lidar, which offers all of the advantages of non-coherent lidar, but with the additional advantage that direct determination of target velocity is possible by measurement of the Doppler shift. By combining the Doppler velocity measurement capability with the inherent high angular resolution and range accuracy of lidar it is possible to construct Doppler images of targets for target motion assessment. A coherent lidar based on a Tm,Ho:YAG 2-micrometer wavelength laser was constructed and successfully field tested on atmospheric targets in 1990. This lidar incorporated an all solid state (laser diode pumped) master oscillator, in conjunction with a flash lamp pumped slave oscillator. Solid-state laser technology is rapidly advancing, and with the advent of high efficiency, high power, semiconductor laser diodes as pump sources, all-solid-state, coherent lidars are a real possibility in the near future. MSFC currently has a feasibility demonstration effort under way which will involve component testing, and preliminary design of an all-solid-state, coherent lidar for automatic rendezvous, and capture. This two year effort, funded by the Director's Discretionary Fund is due for completion in 1992.

Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation

Science.gov (United States)

Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.

1995-01-01

Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be

Influence of woody elements of a Norway spruce canopy on nadir reflectance simulated by the DART model at very high spatial resolution

Czech Academy of Sciences Publication Activity Database

Malenovský, Zbyněk; Martin, E.; Homolová, Lucie; Gastellu-Etchegory, J.P.; Zurita-Milla, R.; Schaepman, M.E.; Pokorný, Radek; Clevers, J.G.P.W.; Cudlín, Pavel

2008-01-01

Roč. 112, - (2008), s. 1-18 ISSN 0034-4257 Grant - others:-(XE) ESA-PECS project No. 98029 Institutional research plan: CEZ:AV0Z6087904 Keywords : woody elements * radiative transfer * DART * Norway spruce canopy * high spatial resolution * LAI * AISA Subject RIV: EH - Ecology, Behaviour Impact factor: 3.943, year: 2008

Combined Radial and Femoral Access Strategy and Radial-Femoral Rendezvous in Patients With Long and Complex Iliac Occlusions.

Science.gov (United States)

Hanna, Elias B; Mogabgab, Owen N; Baydoun, Hassan

2018-01-01

We present cases of complex, calcified iliac occlusive disease revascularized via a combined radial-femoral access strategy. Through a 6-French, 125-cm transradial guiding catheter, antegrade guidewires and catheters are advanced into the iliac occlusion, while retrograde devices are advanced transfemorally. The transradial and transfemoral channels communicate, allowing the devices to cross the occlusion into the true lumen (radial-femoral antegrade-retrograde rendezvous).

Pollinators' mating rendezvous and the evolution of floral advertisement.

Science.gov (United States)

Fishman, Michael A; Hadany, Lilach

2013-01-07

Successful cross-fertilization in plant species that rely on animal pollinators depends not just on the number of pollinator visits, but also on these visits' duration. Furthermore, in non-deceptive pollination, a visit's duration depends on the magnitude of the reward provided to the pollinator. Accordingly, plants that rely on biotic pollination have to partition their investment in cross-fertilization assurance between attracting pollinator visits - advertisement, and rewarding visitors to assure that the visit is of productive duration. Here we analyze these processes by a combination of optimality methods and game theoretical modeling. Our results indicate that the optimality in such allocation of resources depends on the types of reward offered to the pollinators. More precisely, we show that plants that offer both food reward and mating rendezvous to pollinators will evolve to allocate a higher proportion of their cross-fertilization assurance budget to advertisement than plants that offer only food reward. That is, our results indicate that pollinators' mating habits may play a role in floral evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Direct analysis in real time mass spectrometry, a process analytical technology tool for real-time process monitoring in botanical drug manufacturing.

Science.gov (United States)

Wang, Lu; Zeng, Shanshan; Chen, Teng; Qu, Haibin

2014-03-01

A promising process analytical technology (PAT) tool has been introduced for batch processes monitoring. Direct analysis in real time mass spectrometry (DART-MS), a means of rapid fingerprint analysis, was applied to a percolation process with multi-constituent substances for an anti-cancer botanical preparation. Fifteen batches were carried out, including ten normal operations and five abnormal batches with artificial variations. The obtained multivariate data were analyzed by a multi-way partial least squares (MPLS) model. Control trajectories were derived from eight normal batches, and the qualification was tested by R(2) and Q(2). Accuracy and diagnosis capability of the batch model were then validated by the remaining batches. Assisted with high performance liquid chromatography (HPLC) determination, process faults were explained by corresponding variable contributions. Furthermore, a batch level model was developed to compare and assess the model performance. The present study has demonstrated that DART-MS is very promising in process monitoring in botanical manufacturing. Compared with general PAT tools, DART-MS offers a particular account on effective compositions and can be potentially used to improve batch quality and process consistency of samples in complex matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

Rendezvous technique treatment for late-onset biliary leakage after major hepatectomy of a living donor: report of a case.

Science.gov (United States)

Kimura, Koichi; Ikegami, Toru; Yamashita, Yo-ichi; Saeki, Hiroshi; Oki, Eiji; Yoshizumi, Tomoharu; Uchiyama, Hideaki; Kawanaka, Hirofumi; Soejima, Yuji; Morita, Masaru; Shirabe, Ken; Ikeda, Tetsuo; Maehara, Yoshihiko

2013-09-01

Biliary leakage is a major complication after hepatectomy. We report the case of a living-donor liver transplantation (LDLT) donor with a late-onset bile leak from the trifurcation of the hepatic duct who was successfully treated using rendezvous technique. A 52-year-old man underwent extended left hepatectomy for donation and was discharged on postoperative day (PD) 13. However, he was rehospitalized on PD 26 with severe abdominal pain. Physical examination suggested panperitonitis, and abdominocentesis showed bilious ascites. Emergent laparotomy for biliary leakage and peritonitis was performed. There was bilious ascites in the peritoneal cavity. A biliary fistula was recognized at the trifurcation of B8a, B8b, and B5. Intraoperative transhepatic biliary drainage of each bile duct was performed. Endoscopic transpapillary drainage was performed on PD 24. Finally, external drains were removed and complete internal drainage established on PD 70. The bile leak was considered to be the result of injury from electrocautery device. Appropriate making choices of the electrocautery devices enable us to avoid over thermal injury of the liver surface. Rendezvous bidirectional drainage effectively treated late-onset bile leakage from the trifurcation of a hepatic bile duct.

INSPACE CHEMICAL PROPULSION SYSTEMS AT NASA's MARSHALL SPACE FLIGHT CENTER: HERITAGE AND CAPABILITIES

Science.gov (United States)

McRight, P. S.; Sheehy, J. A.; Blevins, J. A.

2005-01-01

NASA s Marshall Space Flight Center (MSFC) is well known for its contributions to large ascent propulsion systems such as the Saturn V rocket and the Space Shuttle external tank, solid rocket boosters, and main engines. This paper highlights a lesser known but very rich side of MSFC-its heritage in the development of in-space chemical propulsion systems and its current capabilities for spacecraft propulsion system development and chemical propulsion research. The historical narrative describes the flight development activities associated with upper stage main propulsion systems such as the Saturn S-IVB as well as orbital maneuvering and reaction control systems such as the S-IVB auxiliary propulsion system, the Skylab thruster attitude control system, and many more recent activities such as Chandra, the Demonstration of Automated Rendezvous Technology (DART), X-37, the X-38 de-orbit propulsion system, the Interim Control Module, the US Propulsion Module, and multiple technology development activities. This paper also highlights MSFC s advanced chemical propulsion research capabilities, including an overview of the center s Propulsion Systems Department and ongoing activities. The authors highlight near-term and long-term technology challenges to which MSFC research and system development competencies are relevant. This paper concludes by assessing the value of the full range of aforementioned activities, strengths, and capabilities in light of NASA s exploration missions.

Prediction of acrylamide formation in biscuits based on fingerprint data generated by ambient ionization mass spectrometry employing direct analysis in real time (DART) ion source

NARCIS (Netherlands)

Vaclavik, Lukas; Capuano, Edoardo; Gökmen, Vural; Hajslova, Jana

2015-01-01

The objective of this study is the evaluation of the potential of high-throughput direct analysis in real time-high resolution mass spectrometry (DART-HRMS) fingerprinting and multivariate regression analysis in prediction of the extent of acrylamide formation in biscuit samples prepared by

Combined radiologic and endoscopic treatment (using the “rendezvous technique”) of a biliary fistula following left hepatectomy

Science.gov (United States)

Gracient, Aurélien; Rebibo, Lionel; Delcenserie, Richard; Yzet, Thierry; Regimbeau, Jean-Marc

2016-01-01

Despite the ongoing decrease in the frequency of complications after hepatectomy, biliary fistulas still occur and are associated with high morbidity and mortality rates. Here, we report on an unusual technique for managing biliary fistula following left hepatectomy in a patient in whom the right posterior segmental duct joined the left hepatic duct. The biliary fistula was treated with a combined radiologic and endoscopic procedure based on the “rendezvous technique”. The clinical outcome was good, and reoperation was not required. PMID:27570431

Ramifications of projectile velocity on the ballistic dart penetration of sand

Science.gov (United States)

Sable, Peter Anthony

With the advent of novel in-situ experimental measurement techniques, highly resolved quantitative observations of dynamic events within granular media can now be made. In particular, high speed imagery and digital analysis now allow for the ballistic behaviors of sand to be examined not only across a range of event velocities but across multiple length scales. In an attempt to further understand the dynamic behavior of granular media, these new experimental developments were implemented utilizing high speed photography coupled with piezo-electric stress gauges to observe visually accessible ballistic events of a dart penetrating Ottawa sand. Projectile velocities ranged from 100 to over 300 meters per second with two distinct chosen fields of view to capture bulk and grain-scale behaviors. Each event was analyzed using the digital image correlation technique, particle image velocimetry from which two dimensional, temporally resolved, velocity fields were extracted, from which bulk granular flow and compaction wave propagation were observed and quantified. By comparing bulk, in situ, velocity field behavior resultant from dart penetration, momentum transfer could be quantified measuring radius of influence or dilatant fluid approximations from which a positive correlation was found across the explored velocity regime, including self similar tendencies. This was, however, not absolute as persistent scatter was observed attributed to granular heterogeneous effects. These were tentatively measured in terms of an irreversible energy amount calculated via energy balance. Grain scale analysis reveals analogous behavior to the bulk response with more chaotic structure, though conclusions were limited by the image processing method to qualitative observations. Even so, critical granular behaviors could be seen, such as densification, pore collapse, and grain fracture from which basic heterogeneous phenomena could be examined. These particularly dominated near nose

Single Balloon Enteroscopy-Assisted ERCP Using Rendezvous Technique for Sharp Angulation of Roux-en-Y Limb in a Patient with Bile Duct Stones

Science.gov (United States)

Itoi, Takao; Ishii, Kentaro; Sofuni, Atsushi; Itokawa, Fumihide; Kurihara, Toshio; Tsuchiya, Takayoshi; Tsuji, Shujiro; Umeda, Junko; Moriyasu, Fuminori

2009-01-01

The acute angulation of Roux-en-Y (R-Y) limb precludes endoscopic access for endoscopic retrograde cholangiopancreatography (ERCP) even using a balloon enteroscopy. Here, we describe a case of successful single balloon enteroscopy (SBE)-assisted ERCP using a rendezvous technique in a patient with sharply angulated R-Y limb in a 79-year-old woman who had bile duct stones. Method. At first, a guidewire was passed antegradely through the major papilla after the needle puncture using percutaneous transhepatic biliary drainage technique. A hydrophilic guidewire with an ERCP catheter was antegradely advanced beyond the Roux limb. After a guidewire was firmly grasped by a snare forceps, it was pulled out of the body, resulting that the enteroscope could advance to the papilla. After papillary dilation, complete removal of bile duct stones was achieved without any procedure-related complication. In conclusion, although further study is needed, SBE-assisted ERCP using a rendezvous technique may have a potential for selected patients. PMID:20169091

Single Balloon Enteroscopy-Assisted ERCP Using Rendezvous Technique for Sharp Angulation of Roux-en-Y Limb in a Patient with Bile Duct Stones

Directory of Open Access Journals (Sweden)

Takao Itoi

2009-01-01

Full Text Available The acute angulation of Roux-en-Y (R-Y limb precludes endoscopic access for endoscopic retrograde cholangiopancreatography (ERCP even using a balloon enteroscopy. Here, we describe a case of successful single balloon enteroscopy (SBE-assisted ERCP using a rendezvous technique in a patient with sharply angulated R-Y limb in a 79-year-old woman who had bile duct stones. Method. At first, a guidewire was passed antegradely through the major papilla after the needle puncture using percutaneous transhepatic biliary drainage technique. A hydrophilic guidewire with an ERCP catheter was antegradely advanced beyond the Roux limb. After a guidewire was firmly grasped by a snare forceps, it was pulled out of the body, resulting that the enteroscope could advance to the papilla. After papillary dilation, complete removal of bile duct stones was achieved without any procedure-related complication. In conclusion, although further study is needed, SBE-assisted ERCP using a rendezvous technique may have a potential for selected patients.

Some guidance on preparing validation plans for the DART Full System Models.

Energy Technology Data Exchange (ETDEWEB)

Gray, Genetha Anne; Hough, Patricia Diane; Hills, Richard Guy (Sandia National Laboratories, Albuquerque, NM)

2009-03-01

Planning is an important part of computational model verification and validation (V&V) and the requisite planning document is vital for effectively executing the plan. The document provides a means of communicating intent to the typically large group of people, from program management to analysts to test engineers, who must work together to complete the validation activities. This report provides guidelines for writing a validation plan. It describes the components of such a plan and includes important references and resources. While the initial target audience is the DART Full System Model teams in the nuclear weapons program, the guidelines are generally applicable to other modeling efforts. Our goal in writing this document is to provide a framework for consistency in validation plans across weapon systems, different types of models, and different scenarios. Specific details contained in any given validation plan will vary according to application requirements and available resources.

Molecular sexing of tucuxi dolphins (Sotalia guianensis and Sotalia fluviatilis using samples from biopsy darting and decomposed carcasses

Directory of Open Access Journals (Sweden)

Haydée A. Cunha

2007-01-01

Full Text Available We tested the zinc-finger sex chromosome-linked genes Zfx/Zfy and the sex-determining region Y (Sry genes for gender determination of biopsy samples from marine and riverine tucuxi dolphins (Sotalia guianensis and S. fluviatilis. We also evaluated the performance of these genes with decomposed carcasses, for which sexing cannot rely on the direct examination of the reproductive tract. Both systems proved reliable for sexing 46 fresh and decomposed samples, making them especially useful when biopsy darting is coupled with photo-identification studies.

Hubble Servicing Challenges Drive Innovation of Shuttle Rendezvous Techniques

Science.gov (United States)

Goodman, John L.; Walker, Stephen R.

2009-01-01

Hubble Space Telescope (HST) servicing, performed by Space Shuttle crews, has contributed to what is arguably one of the most successful astronomy missions ever flown. Both nominal and contingency proximity operations techniques were developed to enable successful servicing, while lowering the risk of damage to HST systems, and improve crew safety. Influencing the development of these techniques were the challenges presented by plume impingement and HST performance anomalies. The design of both the HST and the Space Shuttle was completed before the potential of HST contamination and structural damage by shuttle RCS jet plume impingement was fully understood. Relative navigation during proximity operations has been challenging, as HST was not equipped with relative navigation aids. Since HST reached orbit in 1990, proximity operations design for servicing missions has evolved as insight into plume contamination and dynamic pressure has improved and new relative navigation tools have become available. Servicing missions have provided NASA with opportunities to gain insight into servicing mission design and development of nominal and contingency procedures. The HST servicing experiences and lessons learned are applicable to other programs that perform on-orbit servicing and rendezvous, both human and robotic.

Asteroid Rendezvous Mission Design Using Multiobjective Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

Ya-zhong Luo

2014-01-01

Full Text Available A new preliminary trajectory design method for asteroid rendezvous mission using multiobjective optimization techniques is proposed. This method can overcome the disadvantages of the widely employed Pork-Chop method. The multiobjective integrated launch window and multi-impulse transfer trajectory design model is formulated, which employes minimum-fuel cost and minimum-time transfer as two objective functions. The multiobjective particle swarm optimization (MOPSO is employed to locate the Pareto solution. The optimization results of two different asteroid mission designs show that the proposed approach can effectively and efficiently demonstrate the relations among the mission characteristic parameters such as launch time, transfer time, propellant cost, and number of maneuvers, which will provide very useful reference for practical asteroid mission design. Compared with the PCP method, the proposed approach is demonstrated to be able to provide much more easily used results, obtain better propellant-optimal solutions, and have much better efficiency. The MOPSO shows a very competitive performance with respect to the NSGA-II and the SPEA-II; besides a proposed boundary constraint optimization strategy is testified to be able to improve its performance.

A consensus linkage map of lentil based on DArT markers from three RIL mapping populations.

Directory of Open Access Journals (Sweden)

Duygu Ates

Full Text Available Lentil (Lens culinaris ssp. culinaris Medikus is a diploid (2n = 2x = 14, self-pollinating grain legume with a haploid genome size of about 4 Gbp and is grown throughout the world with current annual production of 4.9 million tonnes.A consensus map of lentil (Lens culinaris ssp. culinaris Medikus was constructed using three different lentils recombinant inbred line (RIL populations, including "CDC Redberry" x "ILL7502" (LR8, "ILL8006" x "CDC Milestone" (LR11 and "PI320937" x "Eston" (LR39.The lentil consensus map was composed of 9,793 DArT markers, covered a total of 977.47 cM with an average distance of 0.10 cM between adjacent markers and constructed 7 linkage groups representing 7 chromosomes of the lentil genome. The consensus map had no gap larger than 12.67 cM and only 5 gaps were found to be between 12.67 cM and 6.0 cM (on LG3 and LG4. The localization of the SNP markers on the lentil consensus map were in general consistent with their localization on the three individual genetic linkage maps and the lentil consensus map has longer map length, higher marker density and shorter average distance between the adjacent markers compared to the component linkage maps.This high-density consensus map could provide insight into the lentil genome. The consensus map could also help to construct a physical map using a Bacterial Artificial Chromosome library and map based cloning studies. Sequence information of DArT may help localization of orientation scaffolds from Next Generation Sequencing data.

A consensus linkage map of lentil based on DArT markers from three RIL mapping populations.

Science.gov (United States)

Ates, Duygu; Aldemir, Secil; Alsaleh, Ahmad; Erdogmus, Semih; Nemli, Seda; Kahriman, Abdullah; Ozkan, Hakan; Vandenberg, Albert; Tanyolac, Bahattin

2018-01-01

Lentil (Lens culinaris ssp. culinaris Medikus) is a diploid (2n = 2x = 14), self-pollinating grain legume with a haploid genome size of about 4 Gbp and is grown throughout the world with current annual production of 4.9 million tonnes. A consensus map of lentil (Lens culinaris ssp. culinaris Medikus) was constructed using three different lentils recombinant inbred line (RIL) populations, including "CDC Redberry" x "ILL7502" (LR8), "ILL8006" x "CDC Milestone" (LR11) and "PI320937" x "Eston" (LR39). The lentil consensus map was composed of 9,793 DArT markers, covered a total of 977.47 cM with an average distance of 0.10 cM between adjacent markers and constructed 7 linkage groups representing 7 chromosomes of the lentil genome. The consensus map had no gap larger than 12.67 cM and only 5 gaps were found to be between 12.67 cM and 6.0 cM (on LG3 and LG4). The localization of the SNP markers on the lentil consensus map were in general consistent with their localization on the three individual genetic linkage maps and the lentil consensus map has longer map length, higher marker density and shorter average distance between the adjacent markers compared to the component linkage maps. This high-density consensus map could provide insight into the lentil genome. The consensus map could also help to construct a physical map using a Bacterial Artificial Chromosome library and map based cloning studies. Sequence information of DArT may help localization of orientation scaffolds from Next Generation Sequencing data.

Rendezvous with connectivity preservation for multi-robot systems with an unknown leader

Science.gov (United States)

Dong, Yi

2018-02-01

This paper studies the leader-following rendezvous problem with connectivity preservation for multi-agent systems composed of uncertain multi-robot systems subject to external disturbances and an unknown leader, both of which are generated by a so-called exosystem with parametric uncertainty. By combining internal model design, potential function technique and adaptive control, two distributed control strategies are proposed to maintain the connectivity of the communication network, to achieve the asymptotic tracking of all the followers to the output of the unknown leader system, as well as to reject unknown external disturbances. It is also worth to mention that the uncertain parameters in the multi-robot systems and exosystem are further allowed to belong to unknown and unbounded sets when applying the second fully distributed control law containing a dynamic gain inspired by high-gain adaptive control or self-tuning regulator.

CNEA/ANL collaboration program to develop an optimized version of DART validation and assessment by means of U{sub 3}Si{sub x} and U{sub 3}O{sub 8-}Al dispersed CNEA miniplate irradiation behavior.

Energy Technology Data Exchange (ETDEWEB)

Solis, D.

1998-10-16

The DART code is based upon a thermomechanical model that can predict swelling, recrystallization, fuel-meat interdiffusion and other issues related with MTR dispersed FE behavior under irradiation. As a part of a common effort to develop an optimized version of DART, a comparison between DART predictions and CNEA miniplates irradiation experimental data was made. The irradiation took place during 1981-82 for U3O8 miniplates and 1985-86 for U{sub 3}Si{sub x} at Oak Ridge Research Reactor (ORR). The microphotographs were studied by means of IMAWIN 3.0 Image Analysis Code and different fission gas bubbles distributions were obtained. Also it was possible to find and identify different morphologic zones. In both kinds of fuels, different phases were recognized, like particle peripheral zones with evidence of Al-U reaction, internal recrystallized zones and bubbles. A very good agreement between code prediction and irradiation results was found. The few discrepancies are due to local, fabrication and irradiation uncertainties, as the presence of U{sub 3}Si phase in U{sub 3}Si{sub 2} particles and effective burnup.

Sheath rendezvous method: a novel distal protection technique during endovascular treatment of subclavian artery occlusions.

Science.gov (United States)

Haraguchi, Takuya; Urasawa, Kazushi; Nakama, Tatsuya; Nakagawa, Yuya; Tan, Michinao; Koshida, Ryoji; Sato, Katsuhiko

2016-10-01

To describe an innovative distal protection technique, "sheath rendezvous method", during endovascular treatment for subclavian arterial occlusions. 4.5F and 6F guiding sheath were inserted from left brachial and common femoral artery, respectively. 0.014″ guidewire retrogradely passed through occlusion and into antegrade sheath to establish a pull-through system. 3.0 mm balloon was used to expand occlusion and anchor to deliver retrograde sheath into antegrade one. Both sheaths locked by balloon dilatation crossed occlusion until antegrade sheath passed over lesion. Balloon expandable stent was delivered within antegrade sheath. Sheath was removed, and stent was implanted. We obtained an excellent outcome without complications.

Observer-Based Stabilization of Spacecraft Rendezvous with Variable Sampling and Sensor Nonlinearity

Directory of Open Access Journals (Sweden)

Zhuoshi Li

2013-01-01

Full Text Available This paper addresses the observer-based control problem of spacecraft rendezvous with nonuniform sampling period. The relative dynamic model is based on the classical Clohessy-Wiltshire equation, and sensor nonlinearity and sampling are considered together in a unified framework. The purpose of this paper is to perform an observer-based controller synthesis by using sampled and saturated output measurements, such that the resulting closed-loop system is exponentially stable. A time-dependent Lyapunov functional is developed which depends on time and the upper bound of the sampling period and also does not grow along the input update times. The controller design problem is solved in terms of the linear matrix inequality method, and the obtained results are less conservative than using the traditional Lyapunov functionals. Finally, a numerical simulation example is built to show the validity of the developed sampled-data control strategy.

Remote control of DART spectrometer and data acquisition and dynamic send of the results through internet by using the JOB function of MEASTRO 32 software

International Nuclear Information System (INIS)

Liu Guorong; Zhang Xiangyang; Liu Xuesheng; Ye Feng

2003-01-01

This paper introduced a method on remote control of DART spectrometer and data Acquisition and dynamic send of the results through Internet by using the JOB function of MEASTRO 32 software and a software programmed with VB. This gave an idea to realize the special networked measurement of spectrometer without the developed tool kit

Concept de Plate-forme Mobile Instrumentée (PMI) pour l'inspection des ouvrages d'art

OpenAIRE

DERKX, F; DUMOULIN, J; SORIN, JL; LEGEAY, V

2002-01-01

L'inspection des ouvrages d'art est une opération nécessaire afin de maintenir le niveau de l'ouvrage et de garantir la sécurité des usagers. C'est une opération normalisée et réalisée périodiquement par des inspecteurs spécialisés. Elle consiste principalement à relever visuellement la totalité des défauts sur l'ensemble de l'ouvrage. Il est question aujourd'hui d'automatiser certaines tâches afin d'améliorer l'efficacité opérationnelle de ces contrôles à l'aide de dispositifs de vision emba...

O Projeto Darte e o desenvolvimento de competências sociais e da autoestima em crianças e adolescentes

OpenAIRE

Messias, Marta

2015-01-01

Tese de mestrado, Psicologia (Secção de Psicologia Clínica e da Saúde, Núcleo de Psicologia Clínica Sistémica), Universidade de Lisboa, Faculdade de Psicologia, 2015 O presente estudo tem como objetivo principal perceber qual o impacto do Projecto Darte na autoestima e nas competências sociais dos seus participantes. O estudo decorreu na região da grande Lisboa com 40 crianças e adolescentes com idades compreendidas entre os 8 e os 17 anos de ambos os sexos. Recorreu-se a uma e...

Rendezvous with Toutatis from the Moon: The Chang'e-2 mission

Science.gov (United States)

Huang, J.; Tang, X.; Meng, L.

2014-07-01

Chang'e-2 probe was the second lunar probe of China, with the main objectives to demonstrate some key features of the new lunar soft landing technology, and its applications to future exploration missions. After completing the planned mission successfully, Chang'e-2 flew away from the Moon and entered into the interplanetary space. Later, at a distance of 7 million km from the Earth, Chang'e-2 encountered asteroid (4179) Toutatis with a very close fly-by distance and obtained colorful images with a 3-m resolution. Given some surplus velocity increment as well as the promotion of autonomous flight ability and improvement of control, propulsion, and thermal systems in the initial design, Chang'e-2 had the capabilities necessary for escaping from the Moon. By taking advantage of the unique features of the Lagrangian point, the first close fly-by of asteroid Toutatis was realized despite the tight constraints of propellant allocation, spacecraft-Earth communication, and coordination of execution sequences. Chang'e-2 realized the Toutatis flyby with a km-level distance at closest approach. In the absence of direct measurement method, based on the principle of relative navigation and through the use of the sequence of target images, we calculated the rendezvous parameters such as relative distance and image resolution. With the help of these parameters, some fine and new scientific discoveries about the asteroid were obtained by techniques of optical measurements and image processing. Starting with an innovative design, followed by high-fidelity testing and demonstration, elaborative implementation, and optimal usage of residual propellant, Chang'e-2 has for the first time successfully explored the Moon, L2 point and an asteroid, while achieving the purpose of 'faster, better, cheaper'. What Chang'e-2 has accomplished was far beyond our expectations. *J. Huang is the chief designer (PI) of Chang'e-2 probe, planned Chang'e-2's multi-objective and multitasking exploration

archiDART v3.0: A new data analysis pipeline allowing the topological analysis of plant root systems.

Science.gov (United States)

Delory, Benjamin M; Li, Mao; Topp, Christopher N; Lobet, Guillaume

2018-01-01

Quantifying plant morphology is a very challenging task that requires methods able to capture the geometry and topology of plant organs at various spatial scales. Recently, the use of persistent homology as a mathematical framework to quantify plant morphology has been successfully demonstrated for leaves, shoots, and root systems. In this paper, we present a new data analysis pipeline implemented in the R package archiDART to analyse root system architectures using persistent homology. In addition, we also show that both geometric and topological descriptors are necessary to accurately compare root systems and assess their natural complexity.

The endoscopic ultrasound-assisted Rendez-Vous technique for treatment of recurrent pancreatitis due to pancreas divisum and ansa pancreatica

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Sergio López-Durán

Full Text Available Endoscopic treatment of pancreatic ductal malformations causing recurrent acute pancreatitis, such as pancreas divisum or ansa pancreatica, is mainly based on the sphincterotomy of the minor papilla. However, the technical complexity of conventional endoscopic retrograde cholangiopancreatography (ERCP is increased in patients presenting anatomical variants like these and it may be unsuccessful. We report the case of a pancreas divisum combined with ansa pancreatica and describe the cannulation and sphincterotomy of the minor papilla using an ultrasound-assisted Rendez-Vous technique.

Combined Surgical and Transhepatic Rendezvous Procedure for Relieving Anastomotic Biliary Obstruction in Children with Liver Transplants.

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Crowley, John; Soltys, Kyle; Sindhi, Rakesh; Baskin, Kevin; Yilmaz, Sabri; Close, Orrie; Medsinge, Avinash

2017-08-01

Four children (3 boys and 1 girl, age 1.4-9.4 y) presented 2-70 months after liver transplantation (mean 26 months) with high-grade narrowing at the surgical anastomosis that could not be crossed at percutaneous transhepatic cholangiography. Each patient was treated with a combined surgical and interventional radiology "rendezvous" procedure. Biliary drainage catheters were left in place for an average of 6 months after the procedure. At a mean 7.5 months after biliary drainage catheter removal, all children were catheter-free without clinical or biochemical evidence of biliary stricture recurrence. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Rendez-vous avec les oeuvres du Musée: le speed dating au MAH : quinze minutes pour convaincre

OpenAIRE

Matthey, David

2015-01-01

Tiré du site internet du blog des Musées d'art et d'histoire (http://blog.mahgeneve.ch): "Lors des soirées Afterwork tenues au MAH durant les mois d'octobre et de novembre, les séances de speed dating – un commentaire d'une quinzaine de minutes consacré à une oeuvre ou à un ensemble d'oeuvres – ont remporté un franc succès. Cet engouement nous conforte dans l'idée d'en faire le fil rouge de nos futures manifestations de fin de journée ! Mais pourquoi cette formule?".

Development of the Ensemble Navy Aerosol Analysis Prediction System (ENAAPS and its application of the Data Assimilation Research Testbed (DART in support of aerosol forecasting

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J. I. Rubin

2016-03-01

Full Text Available An ensemble-based forecast and data assimilation system has been developed for use in Navy aerosol forecasting. The system makes use of an ensemble of the Navy Aerosol Analysis Prediction System (ENAAPS at 1 × 1°, combined with an ensemble adjustment Kalman filter from NCAR's Data Assimilation Research Testbed (DART. The base ENAAPS-DART system discussed in this work utilizes the Navy Operational Global Analysis Prediction System (NOGAPS meteorological ensemble to drive offline NAAPS simulations coupled with the DART ensemble Kalman filter architecture to assimilate bias-corrected MODIS aerosol optical thickness (AOT retrievals. This work outlines the optimization of the 20-member ensemble system, including consideration of meteorology and source-perturbed ensemble members as well as covariance inflation. Additional tests with 80 meteorological and source members were also performed. An important finding of this work is that an adaptive covariance inflation method, which has not been previously tested for aerosol applications, was found to perform better than a temporally and spatially constant covariance inflation. Problems were identified with the constant inflation in regions with limited observational coverage. The second major finding of this work is that combined meteorology and aerosol source ensembles are superior to either in isolation and that both are necessary to produce a robust system with sufficient spread in the ensemble members as well as realistic correlation fields for spreading observational information. The inclusion of aerosol source ensembles improves correlation fields for large aerosol source regions, such as smoke and dust in Africa, by statistically separating freshly emitted from transported aerosol species. However, the source ensembles have limited efficacy during long-range transport. Conversely, the meteorological ensemble generates sufficient spread at the synoptic scale to enable observational impact

Maximizing the Lifetime of Wireless Sensor Networks Using Multiple Sets of Rendezvous

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Bo Li

2015-01-01

Full Text Available In wireless sensor networks (WSNs, there is a “crowded center effect” where the energy of nodes located near a data sink drains much faster than other nodes resulting in a short network lifetime. To mitigate the “crowded center effect,” rendezvous points (RPs are used to gather data from other nodes. In order to prolong the lifetime of WSN further, we propose using multiple sets of RPs in turn to average the energy consumption of the RPs. The problem is how to select the multiple sets of RPs and how long to use each set of RPs. An optimal algorithm and a heuristic algorithm are proposed to address this problem. The optimal algorithm is highly complex and only suitable for small scale WSN. The performance of the proposed algorithms is evaluated through simulations. The simulation results indicate that the heuristic algorithm approaches the optimal one and that using multiple RP sets can significantly prolong network lifetime.

Navigation Strategies for Primitive Solar System Body Rendezvous and Proximity Operations

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Getzandanner, Kenneth M.

2011-01-01

A wealth of scientific knowledge regarding the composition and evolution of the solar system can be gained through reconnaissance missions to primitive solar system bodies. This paper presents analysis of a baseline navigation strategy designed to address the unique challenges of primitive body navigation. Linear covariance and Monte Carlo error analysis was performed on a baseline navigation strategy using simulated data from a· design reference mission (DRM). The objective of the DRM is to approach, rendezvous, and maintain a stable orbit about the near-Earth asteroid 4660 Nereus. The outlined navigation strategy and resulting analyses, however, are not necessarily limited to this specific target asteroid as they may he applicable to a diverse range of mission scenarios. The baseline navigation strategy included simulated data from Deep Space Network (DSN) radiometric tracking and optical image processing (OpNav). Results from the linear covariance and Monte Carlo analyses suggest the DRM navigation strategy is sufficient to approach and perform proximity operations in the vicinity of the target asteroid with meter-level accuracy.

Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach.

Science.gov (United States)

Own, Chung-Ming; Meng, Zhaopeng; Liu, Kehan

2015-09-03

Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs) and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS), which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach

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Chung-Ming Own

2015-09-01

Full Text Available Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS, which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

Analysis of the Genetic Diversity and Population Structure of Austrian and Belgian Wheat Germplasm within a Regional Context Based on DArT Markers

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Mohamed A. El-Esawi

2018-01-01

Full Text Available Analysis of crop genetic diversity and structure provides valuable information needed to broaden the narrow genetic base as well as to enhance the breeding and conservation strategies of crops. In this study, 95 Austrian and Belgian wheat cultivars maintained at the Centre for Genetic Resources (CGN in the Netherlands were characterised using 1052 diversity array technology (DArT markers to evaluate their genetic diversity, relationships and population structure. The rarefacted allelic richness recorded in the Austrian and Belgian breeding pools (A25 = 1.396 and 1.341, respectively indicated that the Austrian germplasm contained a higher genetic diversity than the Belgian pool. The expected heterozygosity (HE values of the Austrian and Belgian pools were 0.411 and 0.375, respectively. Moreover, the values of the polymorphic information content (PIC of the Austrian and Belgian pools were 0.337 and 0.298, respectively. Neighbour-joining tree divided each of the Austrian and Belgian germplasm pools into two genetically distinct groups. The structure analyses of the Austrian and Belgian pools were in a complete concordance with their neighbour-joining trees. Furthermore, the 95 cultivars were compared to 618 wheat genotypes from nine European countries based on a total of 141 common DArT markers in order to place the Austrian and Belgian wheat germplasm in a wider European context. The rarefacted allelic richness (A10 varied from 1.224 (Denmark to 1.397 (Austria. Cluster and principal coordinates (PCoA analyses divided the wheat genotypes of the nine European countries into two main clusters. The first cluster comprised the Northern and Western European wheat genotypes, whereas the second included the Central European cultivars. The structure analysis of the 618 European wheat genotypes was in a complete concordance with the results of cluster and PCoA analyses. Interestingly, a highly significant difference was recorded between regions (26.53%. In

Identification of Eight Synthetic Cannabinoids, Including 5F-AKB48 in Seized Herbal Products Using DART-TOF-MS and LC-QTOF-MS as Nontargeted Screening Methods.

Science.gov (United States)

Moore, Katherine N; Garvin, Demetra; Thomas, Brian F; Grabenauer, Megan

2017-09-01

Synthetic cannabinoids are sprayed onto plant material and smoked for their marijuana-like effects. Clandestine manufacturers modify synthetic cannabinoid structures by creating closely related analogs. Forensic laboratories are tasked with detection of these analog compounds, but targeted analytical methods are often thwarted by the structural modifications. Here, direct analysis in real time coupled to accurate mass time-of-flight mass spectrometry (DART-TOF-MS) in combination with liquid chromatography quadruple time-of-flight mass spectrometry (LC-QTOF-MS) are presented as a screening and nontargeted confirmation method, respectively. Methanol extracts of herbal material were run using both methods. Spectral data from four different herbal products were evaluated by comparing fragmentation pattern, accurate mass and retention time to available reference standards. JWH-018, JWH-019, AM2201, JWH-122, 5F-AKB48, AKB48-N-(4-pentenyl) analog, UR144, and XLR11 were identified in the products. Results demonstrate that DART-TOF-MS affords a useful approach for rapid screening of herbal products for the presence and identification of synthetic cannabinoids. © 2017 American Academy of Forensic Sciences.

Leak or Fistula After Sleeve Gastrectomy: Treatment with Pigtail Drain by the Rendezvous Technique.

Science.gov (United States)

Soufron, Jacques

2015-10-01

After a sleeve gastrectomy, a leak or fistula is a serious complication. Laparoscopic drainage, drainage under US or CT scan control, or endoscopic insertion of a stent can be used, but a major re-operation is sometimes unavoidable. Endoscopic drainage with a pigtail catheter could give more success and fewer complications, but the insertion of the drain is not always possible nor does it always provide a perfect drainage. If a laparoscopic second look appears necessary, it is possible to insert a pigtail drain laparoscopically, but under endoscopic control, ensuring a correct positioning of the drain both in the peritoneal cavity and in the gastric tube. This simultaneous "rendezvous" technique could combine in this situation the advantages of purely surgical techniques and of purely endoscopic or image-guided techniques.

DArT whole genome profiling provides insights on the evolution and taxonomy of edible Banana (Musa spp.).

Science.gov (United States)

Sardos, J; Perrier, X; Doležel, J; Hřibová, E; Christelová, P; Van den Houwe, I; Kilian, A; Roux, N

2016-12-01

Dessert and cooking bananas are vegetatively propagated crops of great importance for both the subsistence and the livelihood of people in developing countries. A wide diversity of diploid and triploid cultivars including AA, AB, AS, AT, AAA, AAB, ABB, AAS and AAT genomic constitutions exists. Within each of this genome groups, cultivars are classified into subgroups that are reported to correspond to varieties clonally derived from each other after a single sexual event. The number of those founding events at the basis of the diversity of bananas is a matter of debate. We analysed a large panel of 575 accessions, 94 wild relatives and 481 cultivated accessions belonging to the section Musa with a set of 498 DArT markers previously developed. DArT appeared successful and accurate to describe Musa diversity and help in the resolution of cultivated banana genome constitution and taxonomy, and highlighted discrepancies in the acknowledged classification of some accessions. This study also argues for at least two centres of domestication corresponding to South-East Asia and New Guinea, respectively. Banana domestication in New Guinea probably followed different schemes that those previously reported where hybridization underpins the emergence of edible banana. In addition, our results suggest that not all wild ancestors of bananas are known, especially in M. acuminata subspecies. We also estimate the extent of the two consecutive bottlenecks in edible bananas by evaluating the number of sexual founding events underlying our sets of edible diploids and triploids, respectively. The attribution of clone identity to each sample of the sets allowed the detection of subgroups represented by several sets of clones. Although morphological characterization of some of the accessions is needed to correct potentially erroneous classifications, some of the subgroups seem polyclonal. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.

Conversion of Percutaneous Cholecystostomy to Endoscopic Gallbladder Stenting by Using the Rendezvous Technique.

Science.gov (United States)

Nam, Kwangwoo; Choi, Jun-Ho

2017-05-01

We report the successful conversion of percutaneous cholecystostomy (PC) to endoscopic transpapillary gallbladder stenting (ETGS) with insertion of an antegrade guidewire into the duodenum. An 84-year-old man presented with severe acute cholecystitis and septic shock. He had significant comorbidities, and emergent PC was successfully performed. Subsequent ETGS was attempted but unsuccessful owing to difficulties with cystic duct cannulation. However, via the PC tract, the guidewire was passed antegradely into the duodenum, and ETGS with a double-pigtail plastic stent was successfully performed with the rendezvous technique. The PC tube was removed, and no recurrence was reported during the 17-month follow-up period. Conversion of PC to ETGS is a viable option in patients with acute cholecystitis who are not candidates for surgery. Antegrade guidewire insertion via the PC tract may increase the success rate of conversion and decrease the risk of procedure-related complications.

Conversion of Percutaneous Cholecystostomy to Endoscopic Gallbladder Stenting by Using the Rendezvous Technique

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Kwangwoo Nam

2017-05-01

Full Text Available We report the successful conversion of percutaneous cholecystostomy (PC to endoscopic transpapillary gallbladder stenting (ETGS with insertion of an antegrade guidewire into the duodenum. An 84-year-old man presented with severe acute cholecystitis and septic shock. He had significant comorbidities, and emergent PC was successfully performed. Subsequent ETGS was attempted but unsuccessful owing to difficulties with cystic duct cannulation. However, via the PC tract, the guidewire was passed antegradely into the duodenum, and ETGS with a double-pigtail plastic stent was successfully performed with the rendezvous technique. The PC tube was removed, and no recurrence was reported during the 17-month follow-up period. Conversion of PC to ETGS is a viable option in patients with acute cholecystitis who are not candidates for surgery. Antegrade guidewire insertion via the PC tract may increase the success rate of conversion and decrease the risk of procedure-related complications.

Using Information from Rendezvous Missions for Best-Case Appraisals of Impact Damage to Planet Earth Caused by Natural Objects

Science.gov (United States)

Arnold, James O.; Chodas, Paul W.; Ulamec, Stephan; Mathias, Donovan L.; Burkhard, Craig D.

2017-01-01

The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions about potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size range of 160 to 290 m in diameter to be discussed at the PDC 2017 is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) what is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its structure and heterogeneity from the surface and throughout its interior? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as inputs for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, andor cratering. Topics presented in this paper include: (i) the devastation predicted by 2017 PDCs impact on land based on initial observations using ATAPs risk assessment capability, (ii) how information corresponding to items (1) to (3) could be obtained

The impact of trauma on the psyche of the individual using the film Belleville Rendez-vous as an illustrative vehicle.

Science.gov (United States)

Waldron, Sharn

2008-09-01

Using the film Belleville Rendez-vous as a vehicle for discussion, this paper argues that whilst a traumatic complex may bring about dissociation of the psyche, this is not the only possibility, nor is dissociation necessarily to be seen solely as a difficulty to be overcome. If trauma is experienced within the context of support and validation, the experience of trauma may generate integration not only of the trauma but also of the growth potential that the trauma has previously inhibited.

Improvement of darts performance following lucid dream practice depends on the number of distractions while rehearsing within the dream - a sleep laboratory pilot study.

Science.gov (United States)

Schädlich, Melanie; Erlacher, Daniel; Schredl, Michael

2017-12-01

In a lucid dream, the dreamer is aware of the dream state and can deliberately practice motor skills. Two field studies indicated that lucid dream practice can improve waking performance in simple motor tasks. The present pilot study investigated the effect of lucid dream practice in a controlled sleep laboratory setting, using a pre-post design with dart throwing in the evening and morning. The experimental group practiced darts in lucid dreams. Because some participants were distracted during lucid dream practice, the group was divided into lucid dreamers with few (n = 4) and many distractions (n = 5). Change of performance was compared to a physical practice group (n = 9) and a control group (n = 9), showing a significant interaction (P = .013, η 2  = .368). Only the lucid dreamers with few distractions improved (18%) significantly over time (P = .005, d = 3.84). Even though these results have to be considered preliminary, the present study indicates that lucid dream practice can be an effective tool in sports practice if lucid dreamers find ways to minimise distractions during lucid dream practice. Moreover, the study emphasises the necessity to investigate lucid dream practice experiences on a qualitative level.

Discrete Anisotropic Radiative Transfer (DART 5 for Modeling Airborne and Satellite Spectroradiometer and LIDAR Acquisitions of Natural and Urban Landscapes

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Jean-Philippe Gastellu-Etchegorry

2015-02-01

Full Text Available Satellite and airborne optical sensors are increasingly used by scientists, and policy makers, and managers for studying and managing forests, agriculture crops, and urban areas. Their data acquired with given instrumental specifications (spectral resolution, viewing direction, sensor field-of-view, etc. and for a specific experimental configuration (surface and atmosphere conditions, sun direction, etc. are commonly translated into qualitative and quantitative Earth surface parameters. However, atmosphere properties and Earth surface 3D architecture often confound their interpretation. Radiative transfer models capable of simulating the Earth and atmosphere complexity are, therefore, ideal tools for linking remotely sensed data to the surface parameters. Still, many existing models are oversimplifying the Earth-atmosphere system interactions and their parameterization of sensor specifications is often neglected or poorly considered. The Discrete Anisotropic Radiative Transfer (DART model is one of the most comprehensive physically based 3D models simulating the Earth-atmosphere radiation interaction from visible to thermal infrared wavelengths. It has been developed since 1992. It models optical signals at the entrance of imaging radiometers and laser scanners on board of satellites and airplanes, as well as the 3D radiative budget, of urban and natural landscapes for any experimental configuration and instrumental specification. It is freely distributed for research and teaching activities. This paper presents DART physical bases and its latest functionality for simulating imaging spectroscopy of natural and urban landscapes with atmosphere, including the perspective projection of airborne acquisitions and LIght Detection And Ranging (LIDAR waveform and photon counting signals.

Gunshot Injury of Pelvi-Ureteric Junction: Management by the Rendezvous Technique.

Science.gov (United States)

Sekhon, Virender; Suryavanshi, Manav

2017-01-01

Background: Gunshot injury of ureter is common, but isolated injury of pelvi-ureteric junction (PUJ) has not been reported. Moreover, its management is evolving from the traditional urinary diversion, stenting followed later by definitive surgical repair to a more upfront minimally invasive endourologic approach. Case Presentation: An adolescent boy presented with gunshot laceration injury of left PUJ with associated small intestinal injury. Radiological investigations confirmed a contained urinary leak. Retrograde stenting was not effective. The same guidewire was retained into the urinoma and an antegrade percutaneous access was obtained. A snare was used to retrieve the guidewire and obtain a through and through access. A ureteropelvic drainage catheter was inserted over this guidewire and secured in the upper ureter, bypassing the region of injury. Three weeks later, the drainage tube was removed and the same tract was used for antegrade stenting. A retrograde pyelogram done 3 months later during stent removal demonstrated no leak. The patient is asymptomatic for urinary symptoms on 6 months of follow-up. Conclusion: Rendezvous technique is a feasible alternative to open repair of gunshot pelvi-ureteric junction injury. Long-term follow-up is awaited.

Some features of stepped and dart-stepped leaders near the ground in natural negative cloud-to-ground lightning discharges

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X. Qie

2002-06-01

Full Text Available Characteristics of the electric fields produced by stepped and dart-stepped leaders 200 µs just prior to the return strokes during natural negative cloud-to-ground (CG lightning discharges have been analyzed by using data from a broad-band slow antenna system with 0.08 µs time resolution in southeastern China. It has been found that the electric field changes between the last stepped leader and the first return stroke could be classified in three categories. The first type is characterized by a small pulse superimposed on the abrupt beginning of the return stroke, and accounts for 42% of all the cases. The second type accounts for 33.3% and is characterized by relatively smooth electric field changes between the last leader pulse and the following return stroke. The third type accounts for 24.7%, and is characterized by small pulses between the last recognizable leader pulse and the following return stroke. On the average, the time interval between the successive leader pulses prior to the first return strokes and subsequent return strokes was 15.8 µs and 9.4 µs, respectively. The distribution of time intervals between successive stepped leader pulses is quite similar to Gaussian distribution while that for dart-stepped leader pulses is more similar to a log-normal distribution. Other discharge features, such as the average time interval between the last leader step and the first return stroke peak, the ratio of the last leader pulse peak to that of the return stroke amplitude are also discussed in the paper.Key words. Meteology and atmospheric dynamics (atmospheric electricity; lightning – Radio science (electromagnetic noise and interference

Some features of stepped and dart-stepped leaders near the ground in natural negative cloud-to-ground lightning discharges

Directory of Open Access Journals (Sweden)

X. Qie

Full Text Available Characteristics of the electric fields produced by stepped and dart-stepped leaders 200 µs just prior to the return strokes during natural negative cloud-to-ground (CG lightning discharges have been analyzed by using data from a broad-band slow antenna system with 0.08 µs time resolution in southeastern China. It has been found that the electric field changes between the last stepped leader and the first return stroke could be classified in three categories. The first type is characterized by a small pulse superimposed on the abrupt beginning of the return stroke, and accounts for 42% of all the cases. The second type accounts for 33.3% and is characterized by relatively smooth electric field changes between the last leader pulse and the following return stroke. The third type accounts for 24.7%, and is characterized by small pulses between the last recognizable leader pulse and the following return stroke. On the average, the time interval between the successive leader pulses prior to the first return strokes and subsequent return strokes was 15.8 µs and 9.4 µs, respectively. The distribution of time intervals between successive stepped leader pulses is quite similar to Gaussian distribution while that for dart-stepped leader pulses is more similar to a log-normal distribution. Other discharge features, such as the average time interval between the last leader step and the first return stroke peak, the ratio of the last leader pulse peak to that of the return stroke amplitude are also discussed in the paper.

Key words. Meteology and atmospheric dynamics (atmospheric electricity; lightning – Radio science (electromagnetic noise and interference

Future earth orbit transportation systems/technology implications

Science.gov (United States)

Henry, B. Z.; Decker, J. P.

1976-01-01

Assuming Space Shuttle technology to be state-of-the-art, projected technological advances to improve the capabilities of single-stage-to-orbit (SSTO) derivatives are examined. An increase of about 30% in payload performance can be expected from upgrading the present Shuttle system through weight and drag reductions and improvements in the propellants and engines. The ODINEX (Optimal Design Integration Executive Computer Program) program has been used to explore design options. An advanced technology SSTO baseline system derived from ODINEX analysis has a conventional wing-body configuration using LOX/LH engines, three with two-position nozzles with expansion ratios of 40 and 200 and four with fixed nozzles with an expansion ratio of 40. Two assisted-takeoff approaches are under consideration in addition to a concept in which the orbital vehicle takes off empty using airbreathing propulsion and carries out a rendezvous with two large cryogenic tankers carrying propellant at an altitude of 6100 m. Further approaches under examination for propulsion, aerothermodynamic design, and design integration are described.

Tsunami source of the 2016 Muisne, Ecuador Earthquake inferred from tide gauge and DART records

Science.gov (United States)

Adriano, B.; Fujii, Y.; Koshimura, S.

2016-12-01

On April 16, 2016 an earthquake occurred in the central coast of Ecuador (0.382°N 79.922°W, Mw=7.8 at 23:58:36.980 UTC according to U.S. Geological Service). It was reported that widespread damage occurred at several towns of Monabi coastal province. According to reports from the Ecuador Government, more than 15,000 buildings were damaged. This earthquake generated a relatively small tsunami that was detected at several tide gauge station as well as offshore DARTs (Deep Ocean Tsunami Detection Buoys). This study aims to investigate the tsunami source of the 2016 Muisne Earthquake using inversion of recorded tsunami waveform signals. The INOCAR (Instituto Oceanográfico de la Armada in Spanish) of the Ecuador provided the tide records of Esmeraldas, Manta, and La Libertad ports. In addition, the DIMAR (Dirección General Marítima in Spanish) of Colombia provided the tide record of Tumaco port. Finally, waveform signal from two DARTs were also employed. These waveform records usually include ocean tides, which we removed by applying a high-pass filter. To estimate the extent of the tsunami source and the slip distribution, we divide the tsunami source into 4 subfaults that covers the aftershock area during one month after the mainshock. The subfault size is 30 km x 60 km with a top depth of 10 km. The focal mechanisms for all the subfaults were taken form the USGS solution of the mainshock. The inversion result showed that the largest slip was located around the epicenter with a maximum value of 3.1 m. The estimated moment magnitude was calculated as Mw=7.78 (5.89E+20 N-m), which is slightly smaller than the proposed by USGS (Mw7.8, moment 7.05E+20 N-m). The estimated slip distribution suggested that the fault rupture started near the epicenter and propagated from north to south. This evidence is supported by the aftershock distribution, which is higher to the south of the epicenter with a main aftershock of Mw=6.0 on April 22.

Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP) procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy) for the management of cholelithiasis with choledocholithiasis.

Science.gov (United States)

Sahoo, Manash Ranjan; Kumar, Anil T; Patnaik, Aashish

2014-07-01

The 'Rendezvous' technique consists of laparoscopic cholecystectomy (LC) standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In 'group-A',41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP) and common bile duct (CBD) clearance and second by LC. In 'group-B', 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5%) and in arm-B in 39 cases (93%). In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22%) and severe pancreatitis in five patients (12%) versus none of the patients (0%) in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient's compliance and prevents unnecessary intervention to CBD.

A Proposed Strategy for the U.S. to Develop and Maintain a Mainstream Capability Suite ("Warehouse") for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond

Science.gov (United States)

Krishnakumar, Kalmanje S.; Stillwater, Ryan A.; Babula, Maria; Moreau, Michael C.; Riedel, J. Ed; Mrozinski, Richard B.; Bradley, Arthur; Bryan, Thomas C.

2012-01-01

The ability of space assets to rendezvous and dock/capture/berth is a fundamental enabler for numerous classes of NASA fs missions, and is therefore an essential capability for the future of NASA. Mission classes include: ISS crew rotation, crewed exploration beyond low-Earth-orbit (LEO), on-orbit assembly, ISS cargo supply, crewed satellite servicing, robotic satellite servicing / debris mitigation, robotic sample return, and robotic small body (e.g. near-Earth object, NEO) proximity operations. For a variety of reasons to be described, NASA programs requiring Automated/Autonomous Rendezvous and Docking/Capture/Berthing (AR&D) capabilities are currently spending an order-of-magnitude more than necessary and taking twice as long as necessary to achieve their AR&D capability, "reinventing the wheel" for each program, and have fallen behind all of our foreign counterparts in AR&D technology (especially autonomy) in the process. To ensure future missions' reliability and crew safety (when applicable), to achieve the noted cost and schedule savings by eliminate costs of continually "reinventing the wheel ", the NASA AR&D Community of Practice (CoP) recommends NASA develop an AR&D Warehouse, detailed herein, which does not exist today. The term "warehouse" is used herein to refer to a toolbox or capability suite that has pre-integrated selectable supply-chain hardware and reusable software components that are considered ready-to-fly, low-risk, reliable, versatile, scalable, cost-effective, architecture and destination independent, that can be confidently utilized operationally on human spaceflight and robotic vehicles over a variety of mission classes and design reference missions, especially beyond LEO. The CoP also believes that it is imperative that NASA coordinate and integrate all current and proposed technology development activities into a cohesive cross-Agency strategy to produce and utilize this AR&D warehouse. An initial estimate indicates that if NASA

Robust adaptive backstepping neural networks control for spacecraft rendezvous and docking with input saturation.

Science.gov (United States)

Xia, Kewei; Huo, Wei

2016-05-01

This paper presents a robust adaptive neural networks control strategy for spacecraft rendezvous and docking with the coupled position and attitude dynamics under input saturation. Backstepping technique is applied to design a relative attitude controller and a relative position controller, respectively. The dynamics uncertainties are approximated by radial basis function neural networks (RBFNNs). A novel switching controller consists of an adaptive neural networks controller dominating in its active region combined with an extra robust controller to avoid invalidation of the RBFNNs destroying stability of the system outside the neural active region. An auxiliary signal is introduced to compensate the input saturation with anti-windup technique, and a command filter is employed to approximate derivative of the virtual control in the backstepping procedure. Globally uniformly ultimately bounded of the relative states is proved via Lyapunov theory. Simulation example demonstrates effectiveness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Flight demonstration of new thruster and green propellant technology on the PRISMA satellite

Science.gov (United States)

Anflo, K.; Möllerberg, R.

2009-11-01

The concept of a storable liquid monopropellant blend for space applications based on ammonium dinitramide (ADN) was invented in 1997, within a co-operation between the Swedish Space Corporation (SSC) and the Swedish Defense Research Agency (FOI). The objective was to develop a propellant which has higher performance and is safer than hydrazine. The work has been performed under contract from the Swedish National Space Board and ESA. The progress of the development has been presented in several papers since 2000. ECAPS, a subsidiary of the Swedish Space Corporation was established in 2000 with the aim to develop and market the novel "high performance green propellant" (HPGP) technology for space applications. The new technology is based on several innovations and patents w.r.t. propellant formulation and thruster design, including a high temperature resistant catalyst and thrust chamber. The first flight demonstration of the HPGP propulsion system will be performed on PRISMA. PRISMA is an international technology demonstration program with Swedish Space Corporation as the Prime Contractor. This paper describes the performance, characteristics, design and verification of the HPGP propulsion system for PRISMA. Compatibility issues related to using a new propellant with COTS components is also discussed. The PRISMA mission includes two satellites in LEO orbit were the focus is on rendezvous and formation flying. One of the satellites will act as a "target" and the main spacecraft performs rendezvous and formation flying maneuvers, where the ECAPS HPGP propulsion system will provide delta-V capability. The PRISMA CDR was held in January 2007. Integration of the flight propulsion system is about to be finalized. The flight opportunity on PRISMA represents a unique opportunity to demonstrate the HPGP propulsion system in space, and thus take a significant step towards its use in future space applications. The launch of PRISMA scheduled to 2009.

Grand challenges in technology enhanced learning outcomes of the 3rd Alpine Rendez-Vous

CERN Document Server

Fischer, Frank; Sutherland, Rosamund; Zirn, Lena

2014-01-01

This book presents a key piece of the vision and strategy developed in STELLAR. It sets out a new mid-term agenda by defining Grand Challenges for research and development in technology-enhanced learning. Other than mere technology prizes, STELLAR Grand Challenges deal with problems at the interface of social and technical sciences. They pose problems that can be solved only in interdisciplinary collaboration. The descriptions of the Grand Challenge Problems were sent out to a number of stakeholders from industry, academia, and policy-making who responded with insightful, creative and critical comments bringing in their specific perspectives. This book will inspire everyone interested in TEL and its neighboring disciplines in their future projects. All of the listed problems, first hints with respect to the approach, measurable success indicators and funding sources are outlined. The challenges focus on what noted experts regard as important upcoming, pending, and innovative fields of research, the solution o...

The use of direct analysis in real time (DART) to assess the levels of inhibitors co-extracted with DNA and the associated impact in quantification and amplification.

Science.gov (United States)

Moreno, Lilliana I; McCord, Bruce R

2016-10-01

The measure of quality in DNA sample processing starts with an effective nucleic acid isolation procedure. Most problems with DNA sample typing can be attributed to low quantity DNA and/or to the presence of inhibitors in the sample. Therefore, establishing which isolation method is best at removing potential inhibitors may help overcome some of the problems analysts encounter by providing useful information in the determination of the optimal approach for any given sample. Direct analysis in real time (DART) mass spectrometry was used in this study to investigate the ability of different extraction methods to remove PCR inhibitors. Methods investigated included both liquid/liquid (phenol-chloroform) and solid phase based robotic procedures, (PrepFiler™ and EZ1 chemistries). Following extraction, samples were analyzed by DART in order to determine the level of remaining inhibitors and then quantified and amplified to determine the effect any remaining inhibitor had on the overall results. The data suggests that organic extraction methods result in detrimental amounts of phenol carryover while automated methods may produce carry-over of bile salts and other chemicals that preferentially bind the solid phase matrix. Both of these effects can have a negative impact in downstream sample processing and genotyping by PCR. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identifying indications for percutaneous (PTC) vs. endoscopic ultrasound (EUS)- guided "rendezvous" procedure in biliary obstruction and incomplete endoscopic retrograde cholangiography (ERC).

Science.gov (United States)

Albert, J G; Finkelmeier, F; Friedrich-Rust, M; Kronenberger, B; Trojan, J; Zeuzem, S; Sarrazin, C

2014-10-01

The variety of rendezvous (RV) procedures has recently been extended by EUS- and PTCD-guided procedures as a complementary means to conventional ERCP. We have identified indication criteria and the potential of biliary PTCD-guided vs. EUS-guided RV. Consecutive patients with bile duct obstruction who underwent RV were included. In all, ERCP alone was unable to achieve treatment success. Indication, technical success, and outcome in PTCD- vs. EUS-guided RV were retrospectively compared to identify criteria that indicate preference of RV technique. Site of obstruction, clinical scenario (stenosis with abscess vs. no abscess) and reason for previous failure of ERC were evaluated. In 32 patients, three different indications for RV procedures were identified: First, a one-step access to assist in failed ERCP (type 1, intra-ductal RV); second, temporary drainage for prolonged treatment of complex biliary disease (type 2, intra-ductal RV), and drainage of cholangio-abscess with re-establishing bile outflow (type 3, intra-abscess RV). Indication of PTCD- vs. EUS-guided rendezvous was competitive in type 1, but exclusive in favor of PTCD in types 2 and 3. The site of biliary obstruction indicated the anatomic location of RV procedures. This classification may help to define inclusion criteria for prospective studies on biliary RV procedures. Choice of therapeutic strategy depends on the anatomic location of the biliary obstruction and the type of the biliary lesion. PTCD-guided RV might improve outcome in cholangio-abscess. © Georg Thieme Verlag KG Stuttgart · New York.

Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique.

Science.gov (United States)

Patrzyk, Maciej; Dierzek, Przemyslaw; Glitsch, Anne; Paul, Hartmut; Heidecke, Claus-Dieter

2015-01-01

Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique) approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ½ year observation period.

Spontaneous Rupture of Superficial Femoral Artery Repaired with Endovascular Stent-Grafting with use of Rendez-Vous Technique, Followed by Delayed Infection

International Nuclear Information System (INIS)

Fanelli, Fabrizio; Cannavale, Alessandro; Gazzetti, Marianna; Fantozzi, Cristiano; Taurino, Maurizio; Speziale, Francesco

2013-01-01

This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient’s clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

Spontaneous Rupture of Superficial Femoral Artery Repaired with Endovascular Stent-Grafting with use of Rendez-Vous Technique, Followed by Delayed Infection

Energy Technology Data Exchange (ETDEWEB)

Fanelli, Fabrizio, E-mail: fabrizio.fanelli@uniroma1.it; Cannavale, Alessandro [University of Rome ' Sapienza,' , Department of Radiological Sciences, Vascular and Interventional Radiology Unit (Italy); Gazzetti, Marianna [Sapienza University of Rome ' Sapienza,' , Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy); Fantozzi, Cristiano; Taurino, Maurizio [University of Rome ' Sapienza,' , Department of Vascular Surgery (Italy); Speziale, Francesco [Sapienza University of Rome ' Sapienza,' , Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy)

2013-02-15

This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient's clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

Spacecraft Actuator Diagnosis with Principal Component Analysis: Application to the Rendez-Vous Phase of the Mars Sample Return Mission

Directory of Open Access Journals (Sweden)

Othman Nasri

2015-01-01

Full Text Available This paper presents a fault detection and isolation (FDI approach in order to detect and isolate actuators (thrusters and reaction wheels faults of an autonomous spacecraft involved in the rendez-vous phase of the Mars Sample Return (MSR mission. The principal component analysis (PCA has been adopted to estimate the relationships between the various variables of the process. To ensure the feasibility of the proposed FDI approach, a set of data provided by the industrial “high-fidelity” simulator of the MSR and representing the opening (resp., the rotation rates of the spacecraft thrusters (resp., reaction wheels has been considered. The test results demonstrate that the fault detection and isolation are successfully accomplished.

Combined Radial-Pedal Access Strategy and Radial-Pedal Rendezvous in the Revascularization of Complex Total Occlusions of the Superficial Femoral Artery (the "No Femoral Access" Strategy).

Science.gov (United States)

Hanna, Elias B; Prout, Davey L

2016-04-01

To describe the combined use of radial-pedal access for recanalization of complex superficial femoral artery (SFA) occlusions unsuitable for transfemoral recanalization. Patients are selected for this strategy if they have a long (≥ 10 cm) SFA occlusion with unfavorable aortoiliac anatomy, an absent ostial stump, or severely diseased and calcified distal reconstitution. Left radial artery and distal anterior or posterior tibial artery are accessed with 6-F and 4-F sheaths, respectively. The SFA lesion is crossed retrogradely with a 0.035-inch wire system. If retrograde crossing is not immediately successful, transradial subintimal tracking and radial-pedal subintimal rendezvous are used to allow retrograde reentry. Fifteen patients (mean age 62 ± 5 years; 11 men) have been treated in this fashion, and frequently stented, through the tibiopedal access. Seven patients required radial-pedal rendezvous to facilitate retrograde reentry. Two patients underwent transradial iliac stenting during the same session, and 1 patient underwent transradial kissing angioplasty of the profunda. No major complication occurred in any patient. After the procedure, the pulse across the accessed tibial artery was palpable in all patients. In patients with long and complex SFA occlusion unsuitable for transfemoral recanalization, a radial-pedal strategy can overcome revascularization obstacles. © The Author(s) 2016.

The influence of spatial ability and experience on performance during spaceship rendezvous and docking.

Science.gov (United States)

Du, Xiaoping; Zhang, Yijing; Tian, Yu; Huang, Weifen; Wu, Bin; Zhang, Jingyu

2015-01-01

Manual rendezvous and docking (manual RVD) is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices, and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed.

The Influence of Spatial Ability and Experience on Spacecraft Rendezvous and Docking Operation Performance

Directory of Open Access Journals (Sweden)

Xiaoping eDu

2015-07-01

Full Text Available Manual rendezvous and docking (manual RVD is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed.

The influence of spatial ability and experience on performance during spaceship rendezvous and docking

Science.gov (United States)

Du, Xiaoping; Zhang, Yijing; Tian, Yu; Huang, Weifen; Wu, Bin; Zhang, Jingyu

2015-01-01

Manual rendezvous and docking (manual RVD) is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices, and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed. PMID:26236252

Basic targeting strategies for rendezvous and flyby missions to the near-Earth asteroids

Science.gov (United States)

Perozzi, Ettore; Rossi, Alessandro; Valsecchi, Giovanni B.

2001-01-01

Missions to asteroids and comets are becoming increasingly feasible both from a technical and a financial point of view. In particular, those directed towards the Near-Earth Asteroids have proven suitable for a low-cost approach, thus attracting the major space agencies as well as private companies. The choice of a suitable target involves both scientific relevance and mission design considerations, being often a difficult task to accomplish due to the limited energy budget at disposal. The aim of this paper is to provide an approach to basic trajectory design which allows to account for both aspects of the problem, taking into account scientific and technical information. A global characterization of the Near-Earth Asteroids population carried out on the basis of their dynamics, physical properties and flight dynamics considerations, allows to identify a group of candidates which satisfy both, the scientific and engineering requirements. The feasibility of rendezvous and flyby missions towards them is then discussed and the possibility of repeated encounters with the same object is investigated, as an intermediate scenario. Within this framework, the capability of present and near future launch and propulsion systems for interplanetary missions is also addressed.

Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique

Directory of Open Access Journals (Sweden)

Maciej Patrzyk

2015-01-01

Full Text Available Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ΍ year observation period.

Clinical differences between younger and older adults with HIV/AIDS starting antiretroviral therapy in Uganda and Zimbabwe: a secondary analysis of the DART trial.

Directory of Open Access Journals (Sweden)

Sujal M Parikh

Full Text Available Clinical and immunological data about HIV in older adults from low and middle income countries is scarce. We aimed to describe differences between younger and older adults with HIV starting antiretroviral therapy in two low-income African countries.HIV clinics in Uganda and Zimbabwe.Secondary exploratory cross-sectional analysis of the DART randomized controlled trial.Clinical and laboratory characteristics were compared between adults aged 18-49 years (younger and ≥ 50 years (older, using two exploratory multivariable logistic regression models, one with HIV viral load (measured in a subset pre-ART and one without.A total of 3316 eligible participants enrolled in DART were available for analysis; 219 (7% were ≥ 50 years and 1160 (35% were male. Across the two adjusted regression models, older adults had significantly higher systolic blood pressure, lower creatinine clearance and were consistently less likely to be females compared to younger adults with HIV. Paradoxically, the models separately suggested that older adults had statistically significant (but not clinically important higher CD4+ cell counts and higher plasma HIV-1 viral copies at initiation. Crude associations between older age and higher baseline hemoglobin, body mass index, diastolic blood pressure and lower WHO clinical stage were not sustained in the adjusted analysis.Our study found clinical and immunological differences between younger and older adults, in a cohort of Africans starting antiretroviral therapy. Further investigations should explore how these differences could be used to ensure equity in service delivery and affect outcomes of antiretroviral therapy.

DART-bid: dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily. High local control in early stage (I/II) non-small-cell lung cancer

Energy Technology Data Exchange (ETDEWEB)

Zehentmayr, Franz; Wurstbauer, Karl; Deutschmann, Heinz; Sedlmayer, Felix [Landeskrankenhaus Salzburg, Univ.-Klinik fuer Radiotherapie und Radio-Onkologie, Univ.-Klinikum der Paracelsus Medizinischen Privatuniversitaet, Salzburg (Austria); Paracelsus Medizinische Privatuniversitaet, Institute for Research and Development of Advanced Radiation Technologies (radART), Salzburg (Austria); Fussl, Christoph; Kopp, Peter; Dagn, Karin; Fastner, Gerd [Landeskrankenhaus Salzburg, Univ.-Klinik fuer Radiotherapie und Radio-Onkologie, Univ.-Klinikum der Paracelsus Medizinischen Privatuniversitaet, Salzburg (Austria); Porsch, Peter; Studnicka, Michael [Landeskrankenhaus Salzburg, Univ.-Klinik fuer Pneumologie, Univ.-Klinikum der Paracelsus Medizinischen Privatuniversitaet, Salzburg (Austria)

2014-09-23

While surgery is considered standard of care for early stage (I/II), non-small-cell lung cancer (NSCLC), radiotherapy is a widely accepted alternative for medically unfit patients or those who refuse surgery. International guidelines recommend several treatment options, comprising stereotactic body radiation therapy (SBRT) for small tumors, conventional radiotherapy ≥ 60 Gy for larger sized especially centrally located lesions or continuous hyperfractionated accelerated RT (CHART). This study presents clinical outcome and toxicity for patients treated with a dose-differentiated accelerated schedule using 1.8 Gy bid (DART-bid). Between April 2002 and December 2010, 54 patients (median age 71 years, median Karnofsky performance score 70 %) were treated for early stage NSCLC. Total doses were applied according to tumor diameter: 73.8 Gy for < 2.5 cm, 79.2 Gy for 2.5-4.5 cm, 84.6 Gy for 4.5-6 cm, 90 Gy for > 6 cm. The median follow-up was 28.5 months (range 2-108 months); actuarial local control (LC) at 2 and 3 years was 88 %, while regional control was 100 %. There were 10 patients (19 %) who died of the tumor, and 18 patients (33 %) died due to cardiovascular or pulmonary causes. A total of 11 patients (20 %) died intercurrently without evidence of progression or treatment-related toxicity at the last follow-up, while 15 patients (28 %) are alive. Acute esophagitis ≤ grade 2 occurred in 7 cases, 2 patients developed grade 2 chronic pulmonary fibrosis. DART-bid yields high LC without significant toxicity. For centrally located and/or large (> 5 cm) early stage tumors, where SBRT is not feasible, this method might serve as radiotherapeutic alternative to present treatment recommendations, with the need of confirmation in larger cohorts. (orig.) [German] Die Standardbehandlung fuer nichtkleinzellige Bronchialkarzinome (NSCLC) im Stadium I/II ist die Operation, wobei Radiotherapie fuer Patienten, die nicht operabel sind oder die Operation ablehnen, als Alternative

A modified technique reduced operative time of laparoendoscopic rendezvous endoscopic retrograde cholangiopancreatography combined with laparoscopic cholecystectomy for concomitant gallstone and common bile ductal stone.

Science.gov (United States)

Liu, Wei; Wang, Qunwei; Xiao, Jing; Zhao, Liying; Huang, Jiangsheng; Tan, Zhaohui; Li, Pengfei

2014-01-01

Laparoendoscopic rendezvous (LERV) endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy (LC+ERCP/LERV) are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1) from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2) who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9%) in group 1 and 24 cases (86.2%) in group 2. The mean operative time and time of endoscopic part were 82.6 ± 19.6 min and 26.5 ± 5.99 min in group 1 which were significantly shorter than those in group 2 (118.0 ± 23.1 min and 58.7 ± 13.3 min, resp.). There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique.

Uncertainty quantification and inference of Manning's friction coefficients using DART buoy data during the Tōhoku tsunami

KAUST Repository

Sraj, Ihab; Mandli, Kyle T.; Knio, Omar; Dawson, Clint N.; Hoteit, Ibrahim

2014-01-01

Tsunami computational models are employed to explore multiple flooding scenarios and to predict water elevations. However, accurate estimation of water elevations requires accurate estimation of many model parameters including the Manning's n friction parameterization. Our objective is to develop an efficient approach for the uncertainty quantification and inference of the Manning's n coefficient which we characterize here by three different parameters set to be constant in the on-shore, near-shore and deep-water regions as defined using iso-baths. We use Polynomial Chaos (PC) to build an inexpensive surrogate for the G. eoC. law model and employ Bayesian inference to estimate and quantify uncertainties related to relevant parameters using the DART buoy data collected during the Tōhoku tsunami. The surrogate model significantly reduces the computational burden of the Markov Chain Monte-Carlo (MCMC) sampling of the Bayesian inference. The PC surrogate is also used to perform a sensitivity analysis.

Uncertainty quantification and inference of Manning's friction coefficients using DART buoy data during the Tōhoku tsunami

KAUST Repository

Sraj, Ihab

2014-11-01

Tsunami computational models are employed to explore multiple flooding scenarios and to predict water elevations. However, accurate estimation of water elevations requires accurate estimation of many model parameters including the Manning\\'s n friction parameterization. Our objective is to develop an efficient approach for the uncertainty quantification and inference of the Manning\\'s n coefficient which we characterize here by three different parameters set to be constant in the on-shore, near-shore and deep-water regions as defined using iso-baths. We use Polynomial Chaos (PC) to build an inexpensive surrogate for the G. eoC. law model and employ Bayesian inference to estimate and quantify uncertainties related to relevant parameters using the DART buoy data collected during the Tōhoku tsunami. The surrogate model significantly reduces the computational burden of the Markov Chain Monte-Carlo (MCMC) sampling of the Bayesian inference. The PC surrogate is also used to perform a sensitivity analysis.

Signatures of the Invisible at the Centre d'Art Contemporain, Geneva, 7 February - 12 May 2002. The multimedia artist Sylvie Blocher chats with Jean-Pierre Merlo (left) and Philippe Charpentier, two of the physicists from CERN she interviewed for her video.

CERN Document Server

Patrice Loïez

2002-01-01

Signatures of the Invisible at the Centre d'Art Contemporain, Geneva, 7 February - 12 May 2002. The multimedia artist Sylvie Blocher chats with Jean-Pierre Merlo (left) and Philippe Charpentier, two of the physicists from CERN she interviewed for her video.

Time and Covariance Threshold Triggered Optimal Uncooperative Rendezvous Using Angles-Only Navigation

Directory of Open Access Journals (Sweden)

Yue You

2017-01-01

Full Text Available A time and covariance threshold triggered optimal maneuver planning method is proposed for orbital rendezvous using angles-only navigation (AON. In the context of Yamanaka-Ankersen orbital relative motion equations, the square root unscented Kalman filter (SRUKF AON algorithm is developed to compute the relative state estimations from a low-volume/mass, power saving, and low-cost optical/infrared camera’s observations. Multi-impulsive Hill guidance law is employed in closed-loop linear covariance analysis model, based on which the quantitative relative position robustness and relative velocity robustness index are defined. By balancing fuel consumption, relative position robustness, and relative velocity robustness, we developed a time and covariance threshold triggered two-level optimal maneuver planning method, showing how these results correlate to past methods and missions and how they could potentially influence future ones. Numerical simulation proved that it is feasible to control the spacecraft with a two-line element- (TLE- level uncertain, 34.6% of range, initial relative state to a 100 m v-bar relative station keeping point, at where the trajectory dispersion reduces to 3.5% of range, under a 30% data gap per revolution on account of the eclipse. Comparing with the traditional time triggered maneuver planning method, the final relative position accuracy is improved by one order and the relative trajectory robustness and collision probability are obviously improved and reduced, respectively.

Dynamical analysis of rendezvous and docking with very large space infrastructures in non-Keplerian orbits

Science.gov (United States)

Colagrossi, Andrea; Lavagna, Michèle

2018-03-01

A space station in the vicinity of the Moon can be exploited as a gateway for future human and robotic exploration of the solar system. The natural location for a space system of this kind is about one of the Earth-Moon libration points. The study addresses the dynamics during rendezvous and docking operations with a very large space infrastructure in an EML2 Halo orbit. The model takes into account the coupling effects between the orbital and the attitude motion in a circular restricted three-body problem environment. The flexibility of the system is included, and the interaction between the modes of the structure and those related with the orbital motion is investigated. A lumped parameter technique is used to represents the flexible dynamics. The parameters of the space station are maintained as generic as possible, in a way to delineate a global scenario of the mission. However, the developed model can be tuned and updated according to the information that will be available in the future, when the whole system will be defined with a higher level of precision.

The Ion Propulsion System for the Solar Electric Propulsion Technology Demonstration Mission

Science.gov (United States)

Herman, Daniel A.; Santiago, Walter; Kamhawi, Hani; Polk, James E.; Snyder, John Steven; Hofer, Richard R.; Parker, J. Morgan

2015-01-01

The Asteroid Redirect Robotic Mission is a candidate Solar Electric Propulsion Technology Demonstration Mission whose main objectives are to develop and demonstrate a high-power solar electric propulsion capability for the Agency and return an asteroidal mass for rendezvous and characterization in a companion human-crewed mission. The ion propulsion system must be capable of operating over an 8-year time period and processing up to 10,000 kg of xenon propellant. This high-power solar electric propulsion capability, or an extensible derivative of it, has been identified as a critical part of an affordable, beyond-low-Earth-orbit, manned-exploration architecture. Under the NASA Space Technology Mission Directorate the critical electric propulsion and solar array technologies are being developed. The ion propulsion system being co-developed by the NASA Glenn Research Center and the Jet Propulsion Laboratory for the Asteroid Redirect Vehicle is based on the NASA-developed 12.5 kW Hall Effect Rocket with Magnetic Shielding (HERMeS0 thruster and power processing technologies. This paper presents the conceptual design for the ion propulsion system, the status of the NASA in-house thruster and power processing activity, and an update on flight hardware.

A Modified Technique Reduced Operative Time of Laparoendoscopic Rendezvous Endoscopic Retrograde Cholangiopancreatography Combined with Laparoscopic Cholecystectomy for Concomitant Gallstone and Common Bile Ductal Stone

Directory of Open Access Journals (Sweden)

Wei Liu

2014-01-01

Full Text Available Laparoendoscopic rendezvous (LERV endoscopic retrograde cholangiopancreatography (ERCP and laparoscopic cholecystectomy (LC+ERCP/LERV are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1 from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2 who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9% in group 1 and 24 cases (86.2% in group 2. The mean operative time and time of endoscopic part were 82.6 ± 19.6 min and 26.5 ± 5.99 min in group 1 which were significantly shorter than those in group 2 (118.0 ± 23.1 min and 58.7 ± 13.3 min, resp.. There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique.

Asynchronous Channel-Hopping Scheme under Jamming Attacks

Directory of Open Access Journals (Sweden)

Yongchul Kim

2018-01-01

Full Text Available Cognitive radio networks (CRNs are considered an attractive technology to mitigate inefficiency in the usage of licensed spectrum. CRNs allow the secondary users (SUs to access the unused licensed spectrum and use a blind rendezvous process to establish communication links between SUs. In particular, quorum-based channel-hopping (CH schemes have been studied recently to provide guaranteed blind rendezvous in decentralized CRNs without using global time synchronization. However, these schemes remain vulnerable to jamming attacks. In this paper, we first analyze the limitations of quorum-based rendezvous schemes called asynchronous channel hopping (ACH. Then, we introduce a novel sequence sensing jamming attack (SSJA model in which a sophisticated jammer can dramatically reduce the rendezvous success rates of ACH schemes. In addition, we propose a fast and robust asynchronous rendezvous scheme (FRARS that can significantly enhance robustness under jamming attacks. Our numerical results demonstrate that the performance of the proposed scheme vastly outperforms the ACH scheme when there are security concerns about a sequence sensing jammer.

Applications of direct analysis in real time-mass spectrometry (DART-MS) in Allium chemistry. (Z)-butanethial S-oxide and 1-butenyl thiosulfinates and their S-(E)-1-butenylcysteine S-oxide precursor from Allium siculum.

Science.gov (United States)

Kubec, Roman; Cody, Robert B; Dane, A John; Musah, Rabi A; Schraml, Jan; Vattekkatte, Abith; Block, Eric

2010-01-27

Lachrymatory (Z)-butanethial S-oxide along with several 1-butenyl thiosulfinates was detected by DART mass spectrometry upon cutting Allium siculum , a popular ornamental Allium species used in some cultures as a spice. (Z)-Butanethial S-oxide isolated from the plant was shown to be identical to a synthetic sample. Its likely precursor, (R(S),R(C),E)-S-(1-butenyl)cysteine S-oxide (homoisoalliin), was isolated from homogenates of A. siculum, and a closely related species Allium tripedale , and fully characterized. Through use of LC-MS, a series of related gamma-glutamyl derivatives were tentatively identified in A. siculum and A. tripedale homogenates, including gamma-glutamyl-(E)-S-(1-butenyl)cysteine and its S-oxide, gamma-glutamyl-S-butylcysteine and its S-oxide, and gamma-glutamyl-S-methylcysteine and its S-oxide. Because compounds containing the 1-butenyl group have not been previously identified in genus Allium species, this work extends the range of known Allium sulfur compounds. The general applicability of DART mass spectrometry in identifying naturally occurring, thermally fragile thial S-oxides and thiosulfinates is illustrated with onion, Allium cepa , as well as a plant from a different genus, Petiveria alliacea .

Hybrid Guidance System for Relative Navigation, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Automated Rendezvous and Capture (AR&C) is a critical United States technology gap. AR&C is identified as a critical enabling technology for future NASA...

DART-bid: dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily. High local control in early stage (I/II) non-small-cell lung cancer

International Nuclear Information System (INIS)

Zehentmayr, Franz; Wurstbauer, Karl; Deutschmann, Heinz; Sedlmayer, Felix; Fussl, Christoph; Kopp, Peter; Dagn, Karin; Fastner, Gerd; Porsch, Peter; Studnicka, Michael

2015-01-01

While surgery is considered standard of care for early stage (I/II), non-small-cell lung cancer (NSCLC), radiotherapy is a widely accepted alternative for medically unfit patients or those who refuse surgery. International guidelines recommend several treatment options, comprising stereotactic body radiation therapy (SBRT) for small tumors, conventional radiotherapy ≥ 60 Gy for larger sized especially centrally located lesions or continuous hyperfractionated accelerated RT (CHART). This study presents clinical outcome and toxicity for patients treated with a dose-differentiated accelerated schedule using 1.8 Gy bid (DART-bid). Between April 2002 and December 2010, 54 patients (median age 71 years, median Karnofsky performance score 70 %) were treated for early stage NSCLC. Total doses were applied according to tumor diameter: 73.8 Gy for 6 cm. The median follow-up was 28.5 months (range 2-108 months); actuarial local control (LC) at 2 and 3 years was 88 %, while regional control was 100 %. There were 10 patients (19 %) who died of the tumor, and 18 patients (33 %) died due to cardiovascular or pulmonary causes. A total of 11 patients (20 %) died intercurrently without evidence of progression or treatment-related toxicity at the last follow-up, while 15 patients (28 %) are alive. Acute esophagitis ≤ grade 2 occurred in 7 cases, 2 patients developed grade 2 chronic pulmonary fibrosis. DART-bid yields high LC without significant toxicity. For centrally located and/or large (> 5 cm) early stage tumors, where SBRT is not feasible, this method might serve as radiotherapeutic alternative to present treatment recommendations, with the need of confirmation in larger cohorts. (orig.) [de

The Space Operations Simulation Center (SOSC) and Closed-Loop Hardware Testing for Orion Rendezvous System Design

Science.gov (United States)

Milenkovic, Zoran; DSouza, Christopher; Huish, David; Bendle, John; Kibler, Angela

2012-01-01

The exploration goals of Orion / MPCV Project will require a mature Rendezvous, Proximity Operations and Docking (RPOD) capability. Ground testing autonomous docking with a next-generation sensor such as the Vision Navigation Sensor (VNS) is a critical step along the path of ensuring successful execution of autonomous RPOD for Orion. This paper will discuss the testing rationale, the test configuration, the test limitations and the results obtained from tests that have been performed at the Lockheed Martin Space Operations Simulation Center (SOSC) to evaluate and mature the Orion RPOD system. We will show that these tests have greatly increased the confidence in the maturity of the Orion RPOD design, reduced some of the latent risks and in doing so validated the design philosophy of the Orion RPOD system. This paper is organized as follows: first, the objectives of the test are given. Descriptions of the SOSC facility, and the Orion RPOD system and associated components follow. The details of the test configuration of the components in question are presented prior to discussing preliminary results of the tests. The paper concludes with closing comments.

Pneumoperitoneum Caused by Air Leakage Through the Percutaneous Puncture Tract as a Complication of Rendezvous Technique: A Case Report

Directory of Open Access Journals (Sweden)

Chiao-Hsiung Chuang

2008-11-01

Full Text Available The rendezvous technique, combining percutaneous and endoscopic procedures, is a safe and effective method to achieve biliary cannulation if an endoscopic approach fails. The two procedures in this technique can be carried out simultaneously or in stages. A simultaneous approach is reported to be associated with fewer complications, and patients undergoing this approach can recover and be discharged more rapidly. Here, we report a complication of pneumoperitoneum in a patient who underwent percutaneous and endoscopic procedures simultaneously for the removal of a common bile duct stone. It was supposed that prolonged air insufflation during endoscopy forced intestinal air to track into the peritoneal cavity through the bile ducts and the puncture tract. Accordingly, a short wait before removing the percutaneous catheter to deflate the intestinal air will be helpful to avoid such a complication.

Authentication of true cinnamon (Cinnamon verum) utilising direct analysis in real time (DART)-QToF-MS.

Science.gov (United States)

Avula, Bharathi; Smillie, Troy J; Wang, Yan-Hong; Zweigenbaum, Jerry; Khan, Ikhlas A

2015-01-01

The use of cinnamon as a spice and flavouring agent is widespread throughout the world. Many different species of plants are commonly referred to as 'cinnamon'. 'True cinnamon' refers to the dried inner bark of Cinnamomum verum J. S. Presl (syn. C. zeylanicum) (Lauraceae). Other 'cinnamon' species, C. cassia (Nees & T. Nees) J. Presl (syn. C. aromaticum Nees) (Chinese cassia), C. loureiroi Nees (Saigon cassia), and C. burmannii (Nees & T. Nees) Blume (Indonesian cassia), commonly known as cassia, are also marketed as cinnamon. Since there is a prevalence of these various types of 'cinnamons' on the market, there is a need to develop a rapid technique that can readily differentiate between true cinnamon (C. verum) and other commonly marketed species. In the present study, coumarin and other marker compounds indicative of 'cinnamon' were analysed using DART-QToF-MS in various samples of cinnamon. This method involved the use of [M + H](+) ions in positive mode in addition to principal component analysis (PCA) using Mass Profiler Professional software to visualise several samples for quality and to discriminate 'true cinnamon' from other Cinnamomum species using the accurate mass capabilities of QToF-MS.

Dry-season retreat and dietary shift of the dart-poison frog Dendrobates tinctorius (Anura: Dendrobatidae

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Marga Born

2010-07-01

Full Text Available Seasonal rainfall affects tropical forest dynamics and behaviorof species that are part of these ecosystems. The positive correlation between amphibian activity patterns and rainfall has been demonstrated repeatedly. Members of Dendrobatidae, a clade of Neotropical dart-poison frogs, are well known for their habitat use and behavior during the rainy season, but their behavior during the dry season has received little attention. We studied habitat use and diet of the dendrobatid frog Dendrobates tinctorius in French Guiana during the rainy and dry seasons. Unlike many other dendrobatid frogs, D. tinctorius does not maintain territories for the entire rainy season. Both sexes colonize recently formed canopy-gaps and stay in these forest patches for only a few weeks. The frogs inthese patches consume a great diversity of prey, consisting of ants, beetles, wasps, insect larvae, and mites. During the dry season, frogs move to retreat sites in mature forest, such as palm bracts and tree holes. The frogs are less active and consume fewer prey items in the dry season, and they consume fewer wasps and insect larvae, but more termites. Ants are the most common prey items during both the wet and dry seasons. We discuss the effects of shifts in seasonal habitat use on the territorial behavior of dendrobatid frogs.

Concept designs for NASA's Solar Electric Propulsion Technology Demonstration Mission

Science.gov (United States)

Mcguire, Melissa L.; Hack, Kurt J.; Manzella, David H.; Herman, Daniel A.

2014-01-01

Multiple Solar Electric Propulsion Technology Demonstration Mission were developed to assess vehicle performance and estimated mission cost. Concepts ranged from a 10,000 kilogram spacecraft capable of delivering 4000 kilogram of payload to one of the Earth Moon Lagrange points in support of future human-crewed outposts to a 180 kilogram spacecraft capable of performing an asteroid rendezvous mission after launched to a geostationary transfer orbit as a secondary payload. Low-cost and maximum Delta-V capability variants of a spacecraft concept based on utilizing a secondary payload adapter as the primary bus structure were developed as were concepts designed to be co-manifested with another spacecraft on a single launch vehicle. Each of the Solar Electric Propulsion Technology Demonstration Mission concepts developed included an estimated spacecraft cost. These data suggest estimated spacecraft costs of $200 million - $300 million if 30 kilowatt-class solar arrays and the corresponding electric propulsion system currently under development are used as the basis for sizing the mission concept regardless of launch vehicle costs. The most affordable mission concept developed based on subscale variants of the advanced solar arrays and electric propulsion technology currently under development by the NASA Space Technology Mission Directorate has an estimated cost of $50M and could provide a Delta-V capability comparable to much larger spacecraft concepts.

Spectral analysis and compositing techniques for the Near Earth Asteroid Rendezvous (NEAR Shoemaker), X-ray and Gamma-Ray Spectrometers (XGRS)

CERN Document Server

McClanahan, T P; Nittler, L R; Boynton, W V; Bruckner, J; Squyres, S W; Evans, L G; Bhangoo, J S; Clark, P E; Floyd, S R; McCartney, E; Mikheeva, I; Starr, R D

2001-01-01

An X-ray and Gamma-Ray Spectrometer (XGRS) is on board the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433 Eros. The Eros asteroid is highly oblate and irregular in shape. As a result, analysis methodologies are in many ways a divergence from comparable techniques. Complex temporal, spatial and instrument performance relationships must be accounted for during the analysis process. Field of view and asteroid surface geometry measurements must be modeled and then combined with real measurements of solar, spectral and instrument calibration information to derive scientific results. NEAR is currently orbiting 433 Eros and is in the initial phases of its primary data integration and mapping phases. Initial results have been obtained and bulk chemistry assessments have been obtained through specialized background assessment and data reduction techniques.

Endoscopic dilation of complete oesophageal obstructions with a combined antegrade-retrograde rendezvous technique.

Science.gov (United States)

Bertolini, Reto; Meyenberger, Christa; Putora, Paul Martin; Albrecht, Franziska; Broglie, Martina Anja; Stoeckli, Sandro J; Sulz, Michael Christian

2016-02-21

To investigate the combined antegrade-retrograde endoscopic rendezvous technique for complete oesophageal obstruction and the swallowing outcome. This single-centre case series includes consecutive patients who were unable to swallow due to complete oesophageal obstruction and underwent combined antegrade-retrograde endoscopic dilation (CARD) within the last 10 years. The patients' demographic characteristics, clinical parameters, endoscopic therapy, adverse events, and outcomes were obtained retrospectively. Technical success was defined as effective restoration of oesophageal patency. Swallowing success was defined as either percutaneous endoscopic gastrostomy (PEG)-tube independency and/or relevant improvement of oral food intake, as assessed by the functional oral intake scale (FOIS) (≥ level 3). The cohort consisted of six patients [five males; mean age 71 years (range, 54-74)]. All but one patient had undergone radiotherapy for head and neck or oesophageal cancer. Technical success was achieved in five out of six patients. After discharge, repeated dilations were performed in all five patients. During follow-up (median 27 mo, range, 2-115), three patients remained PEG-tube dependent. Three of four patients achieved relevant improvement of swallowing (two patients: FOIS 6, one patient: FOIS 7). One patient developed mediastinal emphysema following CARD, without a need for surgery. The CARD technique is safe and a viable alternative to high-risk blind antegrade dilation in patients with complete proximal oesophageal obstruction. Although only half of the patients remained PEG-tube independent, the majority improved their ability to swallow.

Guidance, Navigation, and Control Techniques and Technologies for Active Satellite Removal

Science.gov (United States)

Ortega Hernando, Guillermo; Erb, Sven; Cropp, Alexander; Voirin, Thomas; Dubois-Matra, Olivier; Rinalducci, Antonio; Visentin, Gianfranco; Innocenti, Luisa; Raposo, Ana

2013-09-01

This paper shows an internal feasibility analysis to de- orbit a non-functional satellite of big dimensions by the Technical Directorate of the European Space Agency ESA. The paper focuses specifically on the design of the techniques and technologies for the Guidance, Navigation, and Control (GNC) system of the spacecraft mission that will capture the satellite and ultimately will de-orbit it on a controlled re-entry.The paper explains the guidance strategies to launch, rendezvous, close-approach, and capture the target satellite. The guidance strategy uses chaser manoeuvres, hold points, and collision avoidance trajectories to ensure a safe capture. It also details the guidance profile to de-orbit it in a controlled re-entry.The paper continues with an analysis of the required sensing suite and the navigation algorithms to allow the homing, fly-around, and capture of the target satellite. The emphasis is placed around the design of a system to allow the rendezvous with an un-cooperative target, including the autonomous acquisition of both the orbital elements and the attitude of the target satellite.Analysing the capture phase, the paper provides a trade- off between two selected capture systems: the net and the tentacles. Both are studied from the point of view of the GNC system.The paper analyses as well the advanced algorithms proposed to control the final compound after the capture that will allow the controlled de-orbiting of the assembly in a safe place in the Earth.The paper ends proposing the continuation of this work with the extension to the analysis of the destruction process of the compound in consecutive segments starting from the entry gate to the rupture and break up.

A New Path-Constrained Rendezvous Planning Approach for Large-Scale Event-Driven Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Ahmadreza Vajdi

2018-05-01

Full Text Available We study the problem of employing a mobile-sink into a large-scale Event-Driven Wireless Sensor Networks (EWSNs for the purpose of data harvesting from sensor-nodes. Generally, this employment improves the main weakness of WSNs that is about energy-consumption in battery-driven sensor-nodes. The main motivation of our work is to address challenges which are related to a network’s topology by adopting a mobile-sink that moves in a predefined trajectory in the environment. Since, in this fashion, it is not possible to gather data from sensor-nodes individually, we adopt the approach of defining some of the sensor-nodes as Rendezvous Points (RPs in the network. We argue that RP-planning in this case is a tradeoff between minimizing the number of RPs while decreasing the number of hops for a sensor-node that needs data transformation to the related RP which leads to minimizing average energy consumption in the network. We address the problem by formulating the challenges and expectations as a Mixed Integer Linear Programming (MILP. Henceforth, by proving the NP-hardness of the problem, we propose three effective and distributed heuristics for RP-planning, identifying sojourn locations, and constructing routing trees. Finally, experimental results prove the effectiveness of our approach.

A New Path-Constrained Rendezvous Planning Approach for Large-Scale Event-Driven Wireless Sensor Networks.

Science.gov (United States)

Vajdi, Ahmadreza; Zhang, Gongxuan; Zhou, Junlong; Wei, Tongquan; Wang, Yongli; Wang, Tianshu

2018-05-04

We study the problem of employing a mobile-sink into a large-scale Event-Driven Wireless Sensor Networks (EWSNs) for the purpose of data harvesting from sensor-nodes. Generally, this employment improves the main weakness of WSNs that is about energy-consumption in battery-driven sensor-nodes. The main motivation of our work is to address challenges which are related to a network’s topology by adopting a mobile-sink that moves in a predefined trajectory in the environment. Since, in this fashion, it is not possible to gather data from sensor-nodes individually, we adopt the approach of defining some of the sensor-nodes as Rendezvous Points (RPs) in the network. We argue that RP-planning in this case is a tradeoff between minimizing the number of RPs while decreasing the number of hops for a sensor-node that needs data transformation to the related RP which leads to minimizing average energy consumption in the network. We address the problem by formulating the challenges and expectations as a Mixed Integer Linear Programming (MILP). Henceforth, by proving the NP-hardness of the problem, we propose three effective and distributed heuristics for RP-planning, identifying sojourn locations, and constructing routing trees. Finally, experimental results prove the effectiveness of our approach.

A New Path-Constrained Rendezvous Planning Approach for Large-Scale Event-Driven Wireless Sensor Networks

Science.gov (United States)

Zhang, Gongxuan; Wang, Yongli; Wang, Tianshu

2018-01-01

We study the problem of employing a mobile-sink into a large-scale Event-Driven Wireless Sensor Networks (EWSNs) for the purpose of data harvesting from sensor-nodes. Generally, this employment improves the main weakness of WSNs that is about energy-consumption in battery-driven sensor-nodes. The main motivation of our work is to address challenges which are related to a network’s topology by adopting a mobile-sink that moves in a predefined trajectory in the environment. Since, in this fashion, it is not possible to gather data from sensor-nodes individually, we adopt the approach of defining some of the sensor-nodes as Rendezvous Points (RPs) in the network. We argue that RP-planning in this case is a tradeoff between minimizing the number of RPs while decreasing the number of hops for a sensor-node that needs data transformation to the related RP which leads to minimizing average energy consumption in the network. We address the problem by formulating the challenges and expectations as a Mixed Integer Linear Programming (MILP). Henceforth, by proving the NP-hardness of the problem, we propose three effective and distributed heuristics for RP-planning, identifying sojourn locations, and constructing routing trees. Finally, experimental results prove the effectiveness of our approach. PMID:29734718

Evaluation of insight training of ambulance drivers in Sweden using DART, a new e-learning tool.

Science.gov (United States)

Albertsson, Pontus; Sundström, Anna

2011-12-01

The aim of the study was to evaluate whether a new e-learning tool for insight training of ambulance drivers can have an effect on drivers' driving behaviors, perceived driving competence, competence to assess risks, self-reflection, and safety attitudes. A quasi-experimental study design, with participants nonrandomly assigned into a control and intervention group, was used. The intervention group participated in the insight-training course and the control group did not. Both groups completed a self- and peer assessment online questionnaire before and after the training. The main finding is that the ambulance drivers assessed themselves through the instruments after the training, with the e-learning tool Driver Access Recording Tool (DART), as safer drivers in the areas of speed adaptation, closing up, and overtaking. In the answers from the group-based evaluation, the ambulance drivers responded that they were more reflective/analytical, had increased their risk awareness, and had changed their driving behaviors. After insight training, the ambulance drivers in this study assessed themselves as safer drivers in several important areas, including speed adaptation, closing up, and overtaking. In future training of ambulance drivers there should be more focus on insight training instead of previous training focusing on maneuvering capabilities.

Impact of marker ascertainment bias on genomic selection accuracy and estimates of genetic diversity.

Directory of Open Access Journals (Sweden)

Nicolas Heslot

Full Text Available Genome-wide molecular markers are often being used to evaluate genetic diversity in germplasm collections and for making genomic selections in breeding programs. To accurately predict phenotypes and assay genetic diversity, molecular markers should assay a representative sample of the polymorphisms in the population under study. Ascertainment bias arises when marker data is not obtained from a random sample of the polymorphisms in the population of interest. Genotyping-by-sequencing (GBS is rapidly emerging as a low-cost genotyping platform, even for the large, complex, and polyploid wheat (Triticum aestivum L. genome. With GBS, marker discovery and genotyping occur simultaneously, resulting in minimal ascertainment bias. The previous platform of choice for whole-genome genotyping in many species such as wheat was DArT (Diversity Array Technology and has formed the basis of most of our knowledge about cereals genetic diversity. This study compared GBS and DArT marker platforms for measuring genetic diversity and genomic selection (GS accuracy in elite U.S. soft winter wheat. From a set of 365 breeding lines, 38,412 single nucleotide polymorphism GBS markers were discovered and genotyped. The GBS SNPs gave a higher GS accuracy than 1,544 DArT markers on the same lines, despite 43.9% missing data. Using a bootstrap approach, we observed significantly more clustering of markers and ascertainment bias with DArT relative to GBS. The minor allele frequency distribution of GBS markers had a deficit of rare variants compared to DArT markers. Despite the ascertainment bias of the DArT markers, GS accuracy for three traits out of four was not significantly different when an equal number of markers were used for each platform. This suggests that the gain in accuracy observed using GBS compared to DArT markers was mainly due to a large increase in the number of markers available for the analysis.

Impact of Marker Ascertainment Bias on Genomic Selection Accuracy and Estimates of Genetic Diversity

Science.gov (United States)

Heslot, Nicolas; Rutkoski, Jessica; Poland, Jesse; Jannink, Jean-Luc; Sorrells, Mark E.

2013-01-01

Genome-wide molecular markers are often being used to evaluate genetic diversity in germplasm collections and for making genomic selections in breeding programs. To accurately predict phenotypes and assay genetic diversity, molecular markers should assay a representative sample of the polymorphisms in the population under study. Ascertainment bias arises when marker data is not obtained from a random sample of the polymorphisms in the population of interest. Genotyping-by-sequencing (GBS) is rapidly emerging as a low-cost genotyping platform, even for the large, complex, and polyploid wheat (Triticum aestivum L.) genome. With GBS, marker discovery and genotyping occur simultaneously, resulting in minimal ascertainment bias. The previous platform of choice for whole-genome genotyping in many species such as wheat was DArT (Diversity Array Technology) and has formed the basis of most of our knowledge about cereals genetic diversity. This study compared GBS and DArT marker platforms for measuring genetic diversity and genomic selection (GS) accuracy in elite U.S. soft winter wheat. From a set of 365 breeding lines, 38,412 single nucleotide polymorphism GBS markers were discovered and genotyped. The GBS SNPs gave a higher GS accuracy than 1,544 DArT markers on the same lines, despite 43.9% missing data. Using a bootstrap approach, we observed significantly more clustering of markers and ascertainment bias with DArT relative to GBS. The minor allele frequency distribution of GBS markers had a deficit of rare variants compared to DArT markers. Despite the ascertainment bias of the DArT markers, GS accuracy for three traits out of four was not significantly different when an equal number of markers were used for each platform. This suggests that the gain in accuracy observed using GBS compared to DArT markers was mainly due to a large increase in the number of markers available for the analysis. PMID:24040295

"Ultra-rapid" sequential treatment in cholecystocholedocholithiasis: alternative same-day approach to laparoendoscopic rendezvous.

Science.gov (United States)

Borreca, Dario; Bona, Alberto; Bellomo, Maria Paola; Borasi, Andrea; De Paolis, Paolo

2015-12-01

There is still no consensus about timing of laparoscopic cholecystectomy after endoscopic retrograde cholangiopancreatography in the treatment of cholecystocholedocholithiasis. The aim of our retrospective study is to analyze the optimal timing of surgical treatment in patients presenting concurrent choledocholithiasis, choosing to perform a sequential endoscopic plus surgical approach, introducing a same-day two-stage alternative. All cases of cholecystocholedocholithiasis occurred between January 2007 and December 2014 in "Gradenigo" Hospital (Turin-Italy) were reviewed. Patients were divided into three groups, based on the timing of cholecystectomy after endoscopic retrograde cholangiopancreatography, and compared. Out of 2233 cholecystectomies performed in the mentioned time interval, have been identified 93 patients that fulfill the selection criteria. 36 patients were treated with a same-day approach, while 29 within first 72 h and 28 with delayed surgery. The overall length of stay was significantly lower in patients that were treated with a same-day approach (4.7 days), compared with other groups (p = 0.001), while no significant differences were found in terms of length of surgical intervention, intraoperative complications and conversions to open procedure, postoperative stay, morbidity and mortality. Patients treated with delayed surgery had a 18 % recurrency rate of biliary events, with an odds ratio of 14.13 (p = 0.018). Same-day two-stage approach should be performed in suitable patients at the index admission, reducing overall risks, improving the patients' quality-of-life, preventing recurrency, leading to a significant cost abatement; furthermore, this approach allows same outcomes of laparoendoscopic rendezvous, avoiding technical and organizational troubles.

UPSCALING OF SOLAR INDUCED CHLOROPHYLL FLUORESCENCE FROM LEAF TO CANOPY USING THE DART MODEL AND A REALISTIC 3D FOREST SCENE

Directory of Open Access Journals (Sweden)

W. Liu

2017-10-01

Full Text Available Solar induced chlorophyll a fluorescence (SIF has been shown to be an excellent proxy of photosynthesis at multiple scales. However, the mechanical linkages between fluorescence and photosynthesis at the leaf level cannot be directly applied at canopy or field scales, as the larger scale SIF emission depends on canopy structure. This is especially true for the forest canopies characterized by high horizontal and vertical heterogeneity. While most of the current studies on SIF radiative transfer in plant canopies are based on the assumption of a homogeneous canopy, recently codes have been developed capable of simulation of fluorescence signal in explicit 3-D forest canopies. Here we present a canopy SIF upscaling method consisting of the integration of the 3-D radiative transfer model DART and a 3-D object model BLENDER. Our aim was to better understand the effect of boreal forest canopy structure on SIF for a spatially explicit forest canopy.

Using Spoken Language to Facilitate Military Transportation Planning

National Research Council Canada - National Science Library

Bates, Madeleine; Ellard, Dan; Peterson, Pat; Shaked, Varda

1991-01-01

.... In an effort to demonstrate the relevance of SIS technology to real-world military applications, BBN has undertaken the task of providing a spoken language interface to DART, a system for military...

Endoscopic Ultrasound-guided Rendezvous Technique after Failed Endoscopic Retrograde Cholangiopancreatography: Which Approach Route Is the Best?

Science.gov (United States)

Okuno, Nozomi; Hara, Kazuo; Mizuno, Nobumasa; Hijioka, Susumu; Tajika, Masahiro; Tanaka, Tsutomu; Ishihara, Makoto; Hirayama, Yutaka; Onishi, Sachiyo; Niwa, Yasumasa; Yamao, Kenji

2017-12-01

Objective The endoscopic ultrasound-guided rendezvous technique (EUS-RV) is a salvage method for failed selective biliary cannulation. Three puncture routes have been reported, with many comparisons between the intra-hepatic and extra-hepatic biliary ducts. We used the trans-esophagus (TE) and trans-jejunum (TJ) routes. In the present study, the utility of EUS-RV for biliary access was evaluated, focusing on the approach routes. Methods and Patients In 39 patients, 42 puncture routes were evaluated in detail. EUS-RV was performed between January 2010 and December 2014. The patients were prospectively enrolled, and their clinical data were retrospectively collected. Results The patients' median age was 71 (range 29-84) years. The indications for endoscopic retrograde cholangiopancreatography (ERCP) were malignant biliary obstruction in 24 patients and benign biliary disease in 15. The technical success rate was 78.6% (33/42) and was similar among approach routes (p=0.377). The overall complication rate was 16.7% (7/42) and was similar among approach routes (p=0.489). However, mediastinal emphysema occurred in 2 TE route EUS-RV patients. No EUS-RV-related deaths occurred. Conclusion EUS-RV proved reliable after failed ERCP. The selection of the appropriate route based on the patient's condition is crucial.

The first genetic map of pigeon pea based on diversity arrays ...

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... a total of 554 diversity arrays technology (DArT) markers showed ... EH Graham Centre for Agricultural Innovation (NSW Department of Industry and ... India; Theme-Comparative and Applied Genomics, Generation Challenge ...

Phenotypic and molecular variation in the green and black poison-dart frog Dendrobates auratus (Anura: Dendrobatidae from Costa Rica

Directory of Open Access Journals (Sweden)

Lisa D Patrick

2009-11-01

Full Text Available The green and black poison-dart frog Dendrobates auratus exhibits high intraspecific variation in hue color and pattern throughout its range, making it a very popular species in the pet trade. We analyzed the correspondence between color variation and molecular variation of D. auratus from Costa Rica using RAPD analysis. Twenty-six random primers were analyzed for variation in 99 individuals from seven populations. Color pattern was scored from digital images of the dorsal and ventral views. In general, frogs from the Caribbean coast had significantly more light coloration than black color but cannot be grouped by population based only on hue pattern. Only 3 RAPD primers were found to be polymorphic, representing a total of 16 loci. Most of the molecular variation encountered here occurs within populations, thus making unclear the degree of population structure and differentiation. Further examination of COI mtDNA sequences from our samples also supports these results. Partial Mantel correlations suggested that the pattern of molecular variation is not congruent with the variation in color pattern in this species, an outcome that is discussed in terms of phenotypic evolution. Rev. Biol. Trop. 57 (Suppl. 1: 313-321. Epub 2009 November 30.

A novel "hitch-and-ride" deep biliary cannulation method during rendezvous endoscopic ultrasound-guided ERCP technique.

Science.gov (United States)

Nakai, Yousuke; Isayama, Hiroyuki; Matsubara, Saburo; Kogure, Hirofumi; Mizuno, Suguru; Hamada, Tsuyoshi; Takahara, Naminatsu; Nakamura, Tomoka; Sato, Tatsuya; Takeda, Tsuyoshi; Hakuta, Ryunosuke; Ishigaki, Kazunaga; Saito, Kei; Tada, Minoru; Koike, Kazuhiko

2017-10-01

Background and study aim Endoscopic ultrasound-guided rendezvous (EUS-RV) is increasingly reported as a treatment option after failed endoscopic retrograde cholangiopancreatography. We developed a novel "hitch-and-ride" catheter for biliary cannulation to reduce the risk of guidewire loss during EUS-RV. Patients and methods We retrospectively evaluated safety and technical success of EUS-RV between June 2011 and May 2016. Biliary cannulation during EUS-RV using three methods - over-the-wire, along-the-wire, and hitch-and-ride - were compared. Results A total of 30 EUS-RVs were attempted and the technical success rate was 93.3 %, with two failures (one bile duct puncture and one guidewire insertion). After 28 cases of successful guidewire passage, cannulation was attempted by the over-the-wire (n = 13), along-the-wire (n = 4) or hitch-and-ride (n = 11) method. Only the hitch-and-ride method achieved biliary cannulation without guidewire loss or conversion to the other methods. Time to cannulation was shorter with the hitch-and-ride method (4 minutes) than with over-the-wire and along-the-wire methods (9 and 13 minutes, respectively). The adverse event rate of EUS-RV was 23.3 %. Conclusion A novel hitch-and-ride catheter was feasible for biliary cannulation after EUS-RV. © Georg Thieme Verlag KG Stuttgart · New York.

Omnidirectional angle constraint based dynamic six-degree-of-freedom measurement for spacecraft rendezvous and docking simulation

Science.gov (United States)

Shi, Shendong; Yang, Linghui; Lin, Jiarui; Ren, Yongjie; Guo, Siyang; Zhu, Jigui

2018-04-01

In this paper we present a novel omnidirectional angle constraint based method for dynamic 6-DOF (six-degree-of-freedom) measurement. A photoelectric scanning measurement network is employed whose photoelectric receivers are fixed on the measured target. They are in a loop distribution and receive signals from rotating transmitters. Each receiver indicates an angle constraint direction. Therefore, omnidirectional angle constraints can be constructed in each rotation cycle. By solving the constrained optimization problem, 6-DOF information can be obtained, which is independent of traditional rigid coordinate system transformation. For the dynamic error caused by the measurement principle, we present an interpolation method for error reduction. Accuracy testing is performed in an 8  ×  8 m measurement area with four transmitters. The experimental results show that the dynamic orientation RMSEs (root-mean-square errors) are reduced from 0.077° to 0.044°, 0.040° to 0.030° and 0.032° to 0.015° in the X, Y, and Z axes, respectively. The dynamic position RMSE is reduced from 0.65 mm to 0.24 mm. This method is applied during the final approach phase in the rendezvous and docking simulation. Experiments under different conditions are performed in a 40  ×  30 m area, and the method is verified to be effective.

Genome Microscale Heterogeneity among Wild Potatoes Revealed by Diversity Arrays Technology Marker Sequences

Directory of Open Access Journals (Sweden)

Alessandra Traini

2013-01-01

Full Text Available Tuber-bearing potato species possess several genes that can be exploited to improve the genetic background of the cultivated potato Solanum tuberosum. Among them, S. bulbocastanum and S. commersonii are well known for their strong resistance to environmental stresses. However, scant information is available for these species in terms of genome organization, gene function, and regulatory networks. Consequently, genomic tools to assist breeding are meager, and efficient exploitation of these species has been limited so far. In this paper, we employed the reference genome sequences from cultivated potato and tomato and a collection of sequences of 1,423 potato Diversity Arrays Technology (DArT markers that show polymorphic representation across the genomes of S. bulbocastanum and/or S. commersonii genotypes. Our results highlighted microscale genome sequence heterogeneity that may play a significant role in functional and structural divergence between related species. Our analytical approach provides knowledge of genome structural and sequence variability that could not be detected by transcriptome and proteome approaches.

Genome Microscale Heterogeneity among Wild Potatoes Revealed by Diversity Arrays Technology Marker Sequences.

Science.gov (United States)

Traini, Alessandra; Iorizzo, Massimo; Mann, Harpartap; Bradeen, James M; Carputo, Domenico; Frusciante, Luigi; Chiusano, Maria Luisa

2013-01-01

Tuber-bearing potato species possess several genes that can be exploited to improve the genetic background of the cultivated potato Solanum tuberosum. Among them, S. bulbocastanum and S. commersonii are well known for their strong resistance to environmental stresses. However, scant information is available for these species in terms of genome organization, gene function, and regulatory networks. Consequently, genomic tools to assist breeding are meager, and efficient exploitation of these species has been limited so far. In this paper, we employed the reference genome sequences from cultivated potato and tomato and a collection of sequences of 1,423 potato Diversity Arrays Technology (DArT) markers that show polymorphic representation across the genomes of S. bulbocastanum and/or S. commersonii genotypes. Our results highlighted microscale genome sequence heterogeneity that may play a significant role in functional and structural divergence between related species. Our analytical approach provides knowledge of genome structural and sequence variability that could not be detected by transcriptome and proteome approaches.

Classroom sound can be used to classify teaching practices in college science courses.

Science.gov (United States)

Owens, Melinda T; Seidel, Shannon B; Wong, Mike; Bejines, Travis E; Lietz, Susanne; Perez, Joseph R; Sit, Shangheng; Subedar, Zahur-Saleh; Acker, Gigi N; Akana, Susan F; Balukjian, Brad; Benton, Hilary P; Blair, J R; Boaz, Segal M; Boyer, Katharyn E; Bram, Jason B; Burrus, Laura W; Byrd, Dana T; Caporale, Natalia; Carpenter, Edward J; Chan, Yee-Hung Mark; Chen, Lily; Chovnick, Amy; Chu, Diana S; Clarkson, Bryan K; Cooper, Sara E; Creech, Catherine; Crow, Karen D; de la Torre, José R; Denetclaw, Wilfred F; Duncan, Kathleen E; Edwards, Amy S; Erickson, Karen L; Fuse, Megumi; Gorga, Joseph J; Govindan, Brinda; Green, L Jeanette; Hankamp, Paul Z; Harris, Holly E; He, Zheng-Hui; Ingalls, Stephen; Ingmire, Peter D; Jacobs, J Rebecca; Kamakea, Mark; Kimpo, Rhea R; Knight, Jonathan D; Krause, Sara K; Krueger, Lori E; Light, Terrye L; Lund, Lance; Márquez-Magaña, Leticia M; McCarthy, Briana K; McPheron, Linda J; Miller-Sims, Vanessa C; Moffatt, Christopher A; Muick, Pamela C; Nagami, Paul H; Nusse, Gloria L; Okimura, Kristine M; Pasion, Sally G; Patterson, Robert; Pennings, Pleuni S; Riggs, Blake; Romeo, Joseph; Roy, Scott W; Russo-Tait, Tatiane; Schultheis, Lisa M; Sengupta, Lakshmikanta; Small, Rachel; Spicer, Greg S; Stillman, Jonathon H; Swei, Andrea; Wade, Jennifer M; Waters, Steven B; Weinstein, Steven L; Willsie, Julia K; Wright, Diana W; Harrison, Colin D; Kelley, Loretta A; Trujillo, Gloriana; Domingo, Carmen R; Schinske, Jeffrey N; Tanner, Kimberly D

2017-03-21

Active-learning pedagogies have been repeatedly demonstrated to produce superior learning gains with large effect sizes compared with lecture-based pedagogies. Shifting large numbers of college science, technology, engineering, and mathematics (STEM) faculty to include any active learning in their teaching may retain and more effectively educate far more students than having a few faculty completely transform their teaching, but the extent to which STEM faculty are changing their teaching methods is unclear. Here, we describe the development and application of the machine-learning-derived algorithm Decibel Analysis for Research in Teaching (DART), which can analyze thousands of hours of STEM course audio recordings quickly, with minimal costs, and without need for human observers. DART analyzes the volume and variance of classroom recordings to predict the quantity of time spent on single voice (e.g., lecture), multiple voice (e.g., pair discussion), and no voice (e.g., clicker question thinking) activities. Applying DART to 1,486 recordings of class sessions from 67 courses, a total of 1,720 h of audio, revealed varied patterns of lecture (single voice) and nonlecture activity (multiple and no voice) use. We also found that there was significantly more use of multiple and no voice strategies in courses for STEM majors compared with courses for non-STEM majors, indicating that DART can be used to compare teaching strategies in different types of courses. Therefore, DART has the potential to systematically inventory the presence of active learning with ∼90% accuracy across thousands of courses in diverse settings with minimal effort.

Classroom sound can be used to classify teaching practices in college science courses

Science.gov (United States)

Seidel, Shannon B.; Wong, Mike; Bejines, Travis E.; Lietz, Susanne; Perez, Joseph R.; Sit, Shangheng; Subedar, Zahur-Saleh; Acker, Gigi N.; Akana, Susan F.; Balukjian, Brad; Benton, Hilary P.; Blair, J. R.; Boaz, Segal M.; Boyer, Katharyn E.; Bram, Jason B.; Burrus, Laura W.; Byrd, Dana T.; Caporale, Natalia; Carpenter, Edward J.; Chan, Yee-Hung Mark; Chen, Lily; Chovnick, Amy; Chu, Diana S.; Clarkson, Bryan K.; Cooper, Sara E.; Creech, Catherine; Crow, Karen D.; de la Torre, José R.; Denetclaw, Wilfred F.; Duncan, Kathleen E.; Edwards, Amy S.; Erickson, Karen L.; Fuse, Megumi; Gorga, Joseph J.; Govindan, Brinda; Green, L. Jeanette; Hankamp, Paul Z.; Harris, Holly E.; He, Zheng-Hui; Ingalls, Stephen; Ingmire, Peter D.; Jacobs, J. Rebecca; Kamakea, Mark; Kimpo, Rhea R.; Knight, Jonathan D.; Krause, Sara K.; Krueger, Lori E.; Light, Terrye L.; Lund, Lance; Márquez-Magaña, Leticia M.; McCarthy, Briana K.; McPheron, Linda J.; Miller-Sims, Vanessa C.; Moffatt, Christopher A.; Muick, Pamela C.; Nagami, Paul H.; Nusse, Gloria L.; Okimura, Kristine M.; Pasion, Sally G.; Patterson, Robert; Riggs, Blake; Romeo, Joseph; Roy, Scott W.; Russo-Tait, Tatiane; Schultheis, Lisa M.; Sengupta, Lakshmikanta; Small, Rachel; Spicer, Greg S.; Stillman, Jonathon H.; Swei, Andrea; Wade, Jennifer M.; Waters, Steven B.; Weinstein, Steven L.; Willsie, Julia K.; Wright, Diana W.; Harrison, Colin D.; Kelley, Loretta A.; Trujillo, Gloriana; Domingo, Carmen R.; Schinske, Jeffrey N.; Tanner, Kimberly D.

2017-01-01

Active-learning pedagogies have been repeatedly demonstrated to produce superior learning gains with large effect sizes compared with lecture-based pedagogies. Shifting large numbers of college science, technology, engineering, and mathematics (STEM) faculty to include any active learning in their teaching may retain and more effectively educate far more students than having a few faculty completely transform their teaching, but the extent to which STEM faculty are changing their teaching methods is unclear. Here, we describe the development and application of the machine-learning–derived algorithm Decibel Analysis for Research in Teaching (DART), which can analyze thousands of hours of STEM course audio recordings quickly, with minimal costs, and without need for human observers. DART analyzes the volume and variance of classroom recordings to predict the quantity of time spent on single voice (e.g., lecture), multiple voice (e.g., pair discussion), and no voice (e.g., clicker question thinking) activities. Applying DART to 1,486 recordings of class sessions from 67 courses, a total of 1,720 h of audio, revealed varied patterns of lecture (single voice) and nonlecture activity (multiple and no voice) use. We also found that there was significantly more use of multiple and no voice strategies in courses for STEM majors compared with courses for non-STEM majors, indicating that DART can be used to compare teaching strategies in different types of courses. Therefore, DART has the potential to systematically inventory the presence of active learning with ∼90% accuracy across thousands of courses in diverse settings with minimal effort. PMID:28265087

Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy for the management of cholelithiasis with choledocholithiasis

Directory of Open Access Journals (Sweden)

Manash Ranjan Sahoo

2014-01-01

Full Text Available Introduction : The ′Rendezvous′ technique consists of laparoscopic cholecystectomy (LC standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. Materials And Methods: From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In ′group-A′,41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP and common bile duct (CBD clearance and second by LC. In ′group-B′, 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. Results: In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5% and in arm-B in 39 cases (93%. In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22% and severe pancreatitis in five patients (12% versus none of the patients (0% in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. Conclusion: One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient′s compliance and prevents unnecessary intervention to CBD.

Les métamorphoses du livre

OpenAIRE

Chartier, Roger

2015-01-01

Après avoir étudié les conditions de production et de diffusion traditionnelles des livres lors des « Rendez-vous de l'édition », la Bibliothèque propose, en prolongement de ce cycle, les rencontres « Les rendez-vous de l'édition : le livre et le numérique », afin de donner au public des informations et des repères pour comprendre les évolutions en cours. En effet, les technologies numériques permettent de développer ou de renouveler de nombreux produits et services : édition en ligne, livre...

Endoscopic Ultrasound Guided Rendezvous Drainage of Biliary Obstruction Using a New Flexible 19-Gauge Fine Needle Aspiration Needle.

Science.gov (United States)

Tang, Zhouwen; Igbinomwanhia, Efehi; Elhanafi, Sherif; Othman, Mohamed O

2016-01-01

Background and Aim. A successful endoscopic ultrasound guided rendezvous (EUS-RV) biliary drainage is dependent on accurate puncture of the bile duct and precise guide wire manipulation across the ampulla of Vater. We aim to study the feasibility of using a flexible 19-gauge fine aspiration needle in the performance of EUS-RV biliary drainage. Method. This is a retrospective case series of EUS-RV biliary drainage procedures at a single center. Patients who failed ERCP during the same session for benign or malignant biliary obstruction underwent EUS-RV using a flexible, nitinol covered, 19-gauge needle for biliary access and guide wire manipulation. Result. 24 patients underwent EUS-RV biliary drainage via extrahepatic access while 1 attempt was via intrahepatic access. The technical success rate was 80%, including 83.3% of cases via extrahepatic access. There was no significant difference in success rate of inpatient and outpatient procedures, benign or malignant indications, or type of guide wire used. Adverse events included mild pancreatitis (3 patients) and cholangitis (1 patient). Conclusion. A flexible 19-gauge needle for biliary access can be safe and effective when used to perform EUS-RV biliary drainage. Direct comparison between the nitinol needle and conventional metal needles in the performance of EUS guided biliary drainage is needed.

Surgery in biliary lithiasis: from the traditional "open" approach to laparoscopy and the "rendezvous" technique.

Science.gov (United States)

Tarantino, Giuseppe; Magistri, Paolo; Ballarin, Roberto; Assirati, Giacomo; Di Cataldo, Antonio; Di Benedetto, Fabrizio

2017-12-15

According to the current literature, biliary lithiasis is a worldwide-diffused condition that affects almost 20% of the general population. The rate of common bile duct stones (CBDS) in patients with symptomatic cholelithiasis is estimated to be 10% to 33%, depending on patient's age. Compared to stones in the gallbladder, the natural history of secondary CBDS is still not completely understood. It is not clear whether an asymptomatic choledocholithiasis requires treatment or not. For many years, open cholecystectomy with choledochotomy and/or surgical sphincterotomy and cleaning of the bile duct were the gold standard to treat both pathologies. Development of both endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic surgery, together with improvements in diagnostic procedures, influenced new approaches to the management of CBDS in association with gallstones. We decided to systematically review the literature in order to identify all the current therapeutic options for CBDS. A systematic literature search was performed independently by two authors using PubMed, EMBASE, Scopus and the Cochrane Library Central. The therapeutic approach nowadays varies greatly according to the availability of experience and expertise in each center, and includes open or laparoscopic common bile duct exploration, various combinations of laparoscopic cholecystectomy and ERCP and combined laparoendoscopic rendezvous. Although ERCP followed by laparoscopic cholecystectomy is currently preferred in the majority of hospitals worldwide, the optimal treatment for concomitant gallstones and CBDS is still under debate, and greatly varies among different centers. Copyright © 2017 The Editorial Board of Hepatobiliary & Pancreatic Diseases International. Published by Elsevier B.V. All rights reserved.

Comparison of transhepatic and extrahepatic routes for EUS-guided rendezvous procedure for distal CBD obstruction.

Science.gov (United States)

Dhir, Vinay; Bhandari, Suryaprakash; Bapat, Mukta; Joshi, Nitin; Vivekanandarajah, Suhirdan; Maydeo, Amit

2013-04-01

EUS-guided rendezvous procedure (EUS-RV) can be done by the transhepatic (TH) or the extrahepatic (EH) route. There is no data on the preferred access route when both routes are available. To compare the success, complications, and duration of hospitalization for patients undergoing EUS-RV by the TH or the EH route. Patients with distal common bile duct (CBD) obstruction, who failed selective cannulation, underwent EUS-RV by the TH route through the stomach or the EH route through the duodenum. A total of 35 patients were analysed (17 TH, 18 EH). The mean procedure time was significantly longer for the TH group (34.4 vs. 25.7 min; p = 0.0004). There was no difference in the technical success (94.1 vs. 100%). However, the TH group had a higher incidence of post-procedure pain (44.1 vs. 5.5%; p = 0.017), bile leak (11.7 vs. 0; p = 0.228), and air under diaphragm (11.7 vs. 0; p = 0.228). All bile leaks were small and managed conservatively. Duration of hospitalization was significantly higher for the TH group (2.52 vs. 0.17 days; p = 0.015). EUS-RV has similar success rate by the TH or the EH route. However, the TH route has higher post-procedure pain, longer procedure time, and longer duration of hospitalization. The EH route should be preferred for EUS-RV in patients with distal CBD obstruction when both access routes are technically feasible.

Analysis of genetic diversity in pigeon pea germplasm using ...

Indian Academy of Sciences (India)

MANEESHA

2017-08-16

Aug 16, 2017 ... fied polymorphic DNA (RAPD), simple sequence repeats. (SSR), amplified fragment length polymorphism (AFLP), single-nucleotide polymorphisms (SNPs), diversity array technology (DArT), genic-simple sequence repeats (genic-. SSR) etc. (see review by Varshney et al. 2013). Since retrotransposons are ...

Tiangong 1 and Shenzhou 8

Institute of Scientific and Technical Information of China (English)

He Ying

2011-01-01

On September 29,2011,the Tiangong 1 target spacecraft was launched into space by a LM-2FTI launch vehicle thus commencing the rendezvous and docking mission,the second stage of China's Manned Space Program.The Shenzhou 8 spaceship was then launched into space by a LM-2FY8 rocket carrier at 5:58 on November 1,2011.The unmanned Shenzhou 8 successfully docked with Tiangong 1 on November 3.Shenzhou 8 undocked from Tiangong 1 on 14 November and again successfully completed a second rendezvous and docking,confirming a major breakthrough,demonstrating several key technologies in docking,spacecraft complex operation and separation,thus laying a solid foundation for the construction of China's space station.Shenzhou 8 deorbited on 17 November,2011 and landed safely at the main landing site located in the Amu Gulang Grasslands in Siziwangqi,Inner Mongolia Autonomous Region,marking the success of the first rendezvous and docking mission carried out by China.

Direct Analysis in Real Time Mass Spectrometry for Characterization of Large Saccharides.

Science.gov (United States)

Ma, Huiying; Jiang, Qing; Dai, Diya; Li, Hongli; Bi, Wentao; Da Yong Chen, David

2018-03-06

Polysaccharide characterization posts the most difficult challenge to available analytical technologies compared to other types of biomolecules. Plant polysaccharides are reported to have numerous medicinal values, but their effect can be different based on the types of plants, and even regions of productions and conditions of cultivation. However, the molecular basis of the differences of these polysaccharides is largely unknown. In this study, direct analysis in real time mass spectrometry (DART-MS) was used to generate polysaccharide fingerprints. Large saccharides can break down into characteristic small fragments in the DART source via pyrolysis, and the products are then detected by high resolution MS. Temperature was shown to be a crucial parameter for the decomposition of large polysaccharide. The general behavior of carbohydrates in DART-MS was also studied through the investigation of a number of mono- and oligosaccharide standards. The chemical formula and putative ionic forms of the fragments were proposed based on accurate mass with less than 10 ppm mass errors. Multivariate data analysis shows the clear differentiation of different plant species. Intensities of marker ions compared among samples also showed obvious differences. The combination of DART-MS analysis and mechanochemical extraction method used in this work demonstrates a simple, fast, and high throughput analytical protocol for the efficient evaluation of molecular features in plant polysaccharides.

Data Retrieved by ARCADE-R2 Experiment On Board the BEXUS-17 Balloon

Science.gov (United States)

Barbetta, M.; Branz, F.; Carron, A.; Olivieri, L.; Prendin, J.; Sansone, F.; Savioli, L.; Spinello, F.; Francesconi, A.

2015-09-01

The Autonomous Rendezvous, Control And Docking Experiment — Reflight 2 (ARCADE-R2) is a technology demonstrator aiming to prove automatic attitude determination and control, rendezvous and docking capabilities for small scale spacecraft and aircraft. The development of such capabilities could be fundamental to create, in the near future, fleets of cooperative, autonomous unmanned aerial vehicles for mapping, surveillance, inspection and remote observation of hazardous environments; small-class satellites could also benefit from the employment of docking systems to extend and reconfigure their mission profiles. ARCADE-R2 is designed to test these technologies on a stratospheric flight on board the BEXUS-17 balloon, allowing to demonstrate them in a harsh environment subjected to gusty winds and high pressure and temperature variations. In this paper, ARCADE-R2 architecture is introduced and the main results obtained from a stratospheric balloon flight are presented.

Laparoendoscopic rendezvous in the treatment of cholecysto-choledocholitiasis: a single series of 200 patients.

Science.gov (United States)

La Barba, Giuliano; Gardini, Andrea; Cavargini, Elena; Casadei, Alessandro; Morgagni, Paolo; Bazzocchi, Francesca; D'Acapito, Fabrizio; Cavaliere, Davide; Curti, Roberta; Tringali, Domenico; Cucchetti, Alessandro; Ercolani, Giorgio

2018-02-27

Although the ideal management of cholecysto-choledocholitiasis is controversial, the two-stage approach, namely the common bile duct (CBD) clearance through endoscopic retrograde cholangiopancreatography (ERCP) followed by laparoscopic cholecystectomy, remains the standard way of management. However, whenever feasible, the one-stage approach, using the so-called "laparoendoscopic rendezvous" (LERV) technique, offers some advantages, mainly reducing the hospital stay and the risk of post-ERCP pancreatitis. The aim of this study was to evaluate the safety and the efficacy of the one-stage approach, and to compare our results with data from available large studies. We reviewed our series of consecutive patients with cholecysto-choledocholitiasis treated by LERV from January 2003, to October 2016. Both elective and emergency cases were included. The primary end-point was the efficacy to obtain the CBD stones clearance. Secondary end-points were morbidity and mortality, operative time, conversion rate, and in-hospital stay. A total of 200 patients underwent a LERV procedure for the intra-operative diagnosis by intra-operative cholangiogram of cholecysto-choledocholitiasis. In 187 patients (93.5%), it was possible to cannulate the cystic duct with the jag-wire. Success rate was 95%. Conversion rate was 3%. The mean operative time was 135 min and the mean in-hospital stay was 4 days. 29 (14.5%) were the early complications, six mild pancreatitis. Four patients required re-operation during the hospital stay. 11 patients (5.5%) developed late complications during a median follow-up of 57.7 months. Our results confirm that LERV technique is a safe procedure with high success rates for the treatment of cholecysto-choledocholitiasis. The major advantages include the single-stage treatment, the shorter hospital stay, and the lower incidence of post-ERCP pancreatitis.

76 FR 4454 - Privacy Act of 1974; Report of Modified or Altered System of Records

Science.gov (United States)

2011-01-25

... Technology (DART), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control... NIOSH records. Disposal methods include burning or shredding paper materials or transferring records to... paper recycling process when 20 years old, unless needed for further study. VI. OMB Control Numbers...

76 FR 4456 - Privacy Act of 1974; Report of Modified or Altered System of Records

Science.gov (United States)

2011-01-25

... and Prevention (CDC) National Institute for Occupational Safety and Health (NIOSH) Study at Work Sites... Technology (DART), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control... of Records, 09-20-0118, ``Study at Work Sites Where Agents Suspected of Being Occupational Hazards...

A Business Case Analysis of Pre-Positioned Expeditionary Assistance Kit Joint Capability Technology Demonstration

Science.gov (United States)

2013-12-01

WASH activities Deployment of a DART to conduct assessments Cholera and coordrnate with government and relief Zimbabwe Outbreak 12115108 98,592 4,288...436.071 lunanitanan cooclt!or6; arift and local proorerem of ~fbef 5Wploe5 ~of~ teamtoevahate Mexico Hli11Ca.fle 00114/(’fi n.ooo 4 $299,135

Endoscopic Ultrasound-Guided Rendezvous Technique for Failed Biliary Cannulation in Benign and Resectable Malignant Biliary Disorders.

Science.gov (United States)

Shiomi, Hideyuki; Yamao, Kentaro; Hoki, Noriyuki; Hisa, Takeshi; Ogura, Takeshi; Minaga, Kosuke; Masuda, Atsuhiro; Matsumoto, Kazuya; Kato, Hironari; Kamada, Hideki; Goto, Daisuke; Imai, Hajime; Takenaka, Mamoru; Noguchi, Chishio; Nishikiori, Hidefumi; Chiba, Yasutaka; Kutsumi, Hiromu; Kitano, Masayuki

2018-03-01

Endoscopic ultrasound-guided rendezvous technique (EUS-RV) has emerged as an effective salvage method for unsuccessful biliary cannulation. However, its application for benign and resectable malignant biliary disorders has not been fully evaluated. To assess the efficacy and safety of EUS-RV for benign and resectable malignant biliary disorders. This was a multicenter prospective study from 12 Japanese referral centers. Patients who underwent EUS-RV after failed biliary cannulation for biliary disorder were candidates for this study. Inclusion criteria were unsuccessful biliary cannulation for therapeutic endoscopic retrograde cholangiopancreatography with benign and potentially resectable malignant biliary obstruction. Exclusion criteria included unresectable malignant biliary obstruction, inaccessible papillae due to surgically altered upper gastrointestinal anatomy or duodenal stricture, and previous sphincterotomy and/or biliary stent placement. The primary outcome was the technical success rate of biliary cannulation; procedure time, adverse events, and clinical outcomes were secondary outcomes. Twenty patients were prospectively enrolled. The overall technical success rate and median procedure time were 85% and 33 min, respectively. Guidewire manipulation using a 4-Fr tapered tip catheter contributed to the success in advancing the guidewire into the duodenum. Adverse events were identified in 15% patients, including 2 with biliary peritonitis and 1 mild pancreatitis. EUS-RV did not affect surgical maneuvers or complications associated with surgery, or postoperative course. EUS-RV may be a safe and feasible salvage method for unsuccessful biliary cannulation for benign or resectable malignant biliary disorders. Use of a 4-Fr tapered tip catheter may improve the overall EUS-RV success rate.

Advancing Lidar Sensors Technologies for Next Generation Landing Missions

Science.gov (United States)

Amzajerdian, Farzin; Hines, Glenn D.; Roback, Vincent E.; Petway, Larry B.; Barnes, Bruce W.; Brewster, Paul F.; Pierrottet, Diego F.; Bulyshev, Alexander

2015-01-01

Missions to solar systems bodies must meet increasingly ambitious objectives requiring highly reliable "precision landing", and "hazard avoidance" capabilities. Robotic missions to the Moon and Mars demand landing at pre-designated sites of high scientific value near hazardous terrain features, such as escarpments, craters, slopes, and rocks. Missions aimed at paving the path for colonization of the Moon and human landing on Mars need to execute onboard hazard detection and precision maneuvering to ensure safe landing near previously deployed assets. Asteroid missions require precision rendezvous, identification of the landing or sampling site location, and navigation to the highly dynamic object that may be tumbling at a fast rate. To meet these needs, NASA Langley Research Center (LaRC) has developed a set of advanced lidar sensors under the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. These lidar sensors can provide precision measurement of vehicle relative proximity, velocity, and orientation, and high resolution elevation maps of the surface during the descent to the targeted body. Recent flights onboard Morpheus free-flyer vehicle have demonstrated the viability of ALHAT lidar sensors for future landing missions to solar system bodies.

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

a total of 554 diversity arrays technology (DArT) markers showed polymorphism in a pigeon pea F2 mapping population of 72 progenies derived from an interspecific cross of ICP 28 (Cajanus cajan) and ICPW 94 (Cajanus scarabaeoides). Approximately 13% of markers did not conform to expected segregation ratio.

3D Lasers Increase Efficiency, Safety of Moving Machines

Science.gov (United States)

2015-01-01

Canadian company Neptec Design Group Ltd. developed its Laser Camera System, used by shuttles to render 3D maps of their hulls for assessing potential damage. Using NASA funding, the firm incorporated LiDAR technology and created the TriDAR 3D sensor. Its commercial arm, Neptec Technologies Corp., has sold the technology to Orbital Sciences, which uses it to guide its Cygnus spacecraft during rendezvous and dock operations at the International Space Station.

A rendez-vous with history

CERN Multimedia

Corinne Pralavorio

2010-01-01

François de Rose, one of the founding fathers of CERN, visited the Laboratory. On this occasion, CERN organised a ceremony for his 100th birthday.   François de Rose, guided through the CERN control centre by Pierre Strubin from the Technology department. It was a moving, almost surreal, scene. On Wednesday 24 November, François de Rose, one of the founding fathers of CERN, visited the CERN Control Centre. In the early 1950s, François de Rose, a French diplomat, helped establish CERN along with some of the greatest physicists of the time. Standing in a futuristic room that only science fiction writers could have imagined when CERN began, the diplomat – who turned 100 only a few days before his visit - marvelled at the progress that had been made in nearly 60 years. Taking in the rush of operators – including those from PS, an accelerator which he inaugurated as President of the Council in 1960 – François de Rose...

Argon direct analysis in real time mass spectrometry in conjunction with makeup solvents: a method for analysis of labile compounds.

Science.gov (United States)

Yang, Hongmei; Wan, Debin; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

2013-02-05

Helium direct analysis in real time (He-DART) mass spectrometry (MS) analysis of labile compounds usually tends to be challenging because of the occurrence of prominent fragmentation, which obscures the assigning of an ion to an independent species or merely a fragment in a mixture. In the present work, argon DART (Ar-DART) MS in conjunction with makeup solvents has been demonstrated to analyze a variety of labile compounds including nucleosides, alkaloids, glucose, and other small molecules. The results presented here confirm that Ar-DART can generate significantly less energetic ions than conventional He-DART and is able to produce the intact molecular ions with little or no fragmentation in both positive and negative ion modes. Adding a makeup solvent (absolute ethyl alcohol, methanol, fluorobenzene, or acetone) to the argon gas stream at the exit of the DART ion source can result in 1-2 orders of magnitude increase in detection signals. The sensitivity attainable by Ar-DART was found to be comparable to that by He-DART. The investigation of influence of solvents improves our understanding of the fundamental desorption and ionization processes in DART. The practical application of this rapid and high throughput method is demonstrated by the successful analysis of a natural product (Crude Kusnezoff Monkshood) extract, demonstrating the great potential in mixture research.

Cost analysis of laparoendoscopic rendezvous versus preoperative ERCP and laparoscopic cholecystectomy in the management of cholecystocholedocholithiasis.

Science.gov (United States)

Garbarini, Aldo; Reggio, Dario; Arolfo, Simone; Bruno, Marco; Passera, Roberto; Catalano, Giorgia; Barletti, Claudio; Salizzoni, Mauro; Morino, Mario; Petruzzelli, Luca; Arezzo, Alberto

2017-08-01

Evidence from controlled trials and meta-analyses suggests that laparoendoscopic rendezvous (LERV) is preferable to sequential treatment in the management of common bile duct stones. With this retrospective analysis of a prospective database that included consecutive patients treated for cholecystocholedocholithiasis at our institution between January 2007 and July 2015, we compared LERV with sequential treatment. The primary endpoint was global cost, defined as the cost/patient/hospital stay, and the secondary end points were efficacy and morbidity. Fisher's exact test or Mann-Whitney test was used. Of a total of 249 consecutive patients, 143 underwent LERV (group A) and 106 a two-stage procedure (group B). Based on an average cost of €613 for 1 day of hospital stay in the General Surgery Department, the overall median cost of treatment was €6403 for group A and €8194 for group B (p < 0.001). Operative time was significantly shorter (p < 0.001), and length of hospital stay was significantly longer for group B (p < 0.001). No mortality in either group was observed. The postoperative complications rate was significantly higher in group B than in group A (24.5 vs. 10.5%; p = 0.003). No significant difference in the postoperative pancreatitis rate or the number of patients with increased serum amylase at 24 h was observed in either group. Our study suggests that LERV is preferable to sequential treatment not only in terms of less morbidity, but also of lower costs accrued by a shorter hospital stay. However, the longer operative time raises multiple organizational issues in the coordination of surgery and endoscopy services.

Reliability and responsiveness of a goniometric device for measuring the range of motion in the dart-throwing motion plane.

Science.gov (United States)

Kasubuchi, Kenji; Dohi, Yoshihiro; Fujita, Hiroyuki; Fukumoto, Takahiko

2018-02-26

Dart-throwing motion (DTM) is an important component of wrist function and, consequently, has the potential to become an evaluation tool in rehabilitation. However, no measurement method is currently available to reliably measure range of motion (ROM) of the wrist in the DTM plane. To determine the reliability and responsiveness of a goniometric device to measure wrist ROM in the DTM plane. ROM of the wrist in the DTM plane was measured in 70 healthy participants. The intra-class correlation coefficient (ICC) was used to evaluate the relative reliability of measurement, and a Bland-Altman analysis conducted to establish its absolute reliability, including the 95% limits of agreement (95% LOA). The standard error of the measurement (SEM) and minimal detectable change at the 95% confidence level (MDC 95 ) were calculated as measures of responsiveness. The intra-rater ICC was 0.87, and an inter-rater ICC of 0.71. There was no evidence of a fixed or proportional bias. For intra- and inter-rater reliability, 95% LOA ranged from -13.83 to 11.12 and from -17.75 to 16.19, respectively. The SEM and MDC 95 were 4.5° and 12.4°, respectively, for intra-rater reliability, and 6.0° and 16.6°, respectively, for inter-rater reliability. The ROM of the wrist in the DTM plane was measured with fair-to-good reliability and responsiveness and, therefore, has the potential to become an evaluation tool for rehabilitation.

Relationship between automation trust and operator performance for the novice and expert in spacecraft rendezvous and docking (RVD).

Science.gov (United States)

Niu, Jianwei; Geng, He; Zhang, Yijing; Du, Xiaoping

2018-09-01

Operator trust in automation is a crucial factor influencing its use and operational performance. However, the relationship between automation trust and performance remains poorly understood and requires further investigation. The objective of this paper is to explore the difference in trust and performance on automation-aided spacecraft rendezvous and docking (RVD) between the novice and the expert and to investigate the relationship between automation trust and performance as well. We employed a two-factor mixed design, with training skill (novice and expert) and automation mode (manual RVD and automation aided RVD) serving as the two factors. Twenty participants, 10 novices and 10 experts, were recruited to conduct six RVD tasks for two automation levels. After the tasks, operator performance was recorded by the desktop hand-held docking training equipment. Operator trust was also measured by a 12-items questionnaire at the beginning and end of each trial. As a result, automation narrowed the performance gap significantly between the novice and the expert, and the automation trust showed a marginally significant difference between the novice and the expert. Furthermore, the result demonstrated that the attitude angle control error of the expert was related to the total trust score, whereas other automation performance indicators were not related to the total score of trust. However, automation performance was related to the dimensions of trust, such as entrust, harmful, and dependable. Copyright © 2018 Elsevier Ltd. All rights reserved.

Laparoendoscopic rendezvous may be an effective alternative to a failed preoperative endoscopic retrograde cholangiopancreatography in patients with cholecystocholedocholithiasis.

Science.gov (United States)

Tsiopoulos, Fotios; Kapsoritakis, Andreas; Psychos, Athanassios; Manolakis, Anastasios; Oikonomou, Konstantinos; Tzovaras, George; Baloyiannis, Ioannis; Tsikrika, Alexandra; Potamianos, Spyros

2018-01-01

Endoscopic retrograde cholangiopancreatography (ERCP), followed by laparoscopic cholecystectomy (LC), remains the standard way of management for patients with cholecystocholedocholithiasis. Laparoendoscopic rendezvous (LERV), a combined procedure for removing the gallbladder laparoscopically and clearing the common bile duct (CBD) endoscopically at the same time, could be an attractive alternative. The aim of this study was to compare LERV with classic ERCP in patients with cholecystocholedocholithiasis. 886 patients with cholecystocholedocholithiasis were treated either with the LERV technique (90 patients), or with the 2-stage approach, which includes preoperative ERCP followed by LC (796 patients). The primary endpoint was any difference in the success of CBD cannulation and clearance; secondary endpoints were the detection of differences in morbidity (especially post-ERCP pancreatitis [PEP]), and the feasibility of the two approaches. Successful cannulation of the CBD was more frequent with conventional ERCP compared with the LERV technique (89.8% vs. 75.5%, P=0.0001). LERV appears to be as effective as conventional ERCP for complete CBD clearance (85.5% vs. 82.8%, P<0.1). None of the patients in the LERV group had an episode of clinical PEP, whereas in the conventional ERCP group there were 23 episodes of PEP and one death. The median amylase level was higher in patients undergoing conventional ERCP group compared to patients in LERV group. Classic ERCP has a higher rate of successful CBD cannulation and a similar rate of CBD clearance compared to LERV.

NASA's Automated Rendezvous and Docking/Capture Sensor Development and Its Applicability to the GER

Science.gov (United States)

Hinkel, Heather; Cryan, Scott; DSouza, Christopher; Strube, Matthew

2014-01-01

This paper will address how a common Automated Rendezvous and Docking/Capture (AR&D/C) sensor suite can support Global Exploration Roadmap (GER) missions, and discuss how the model of common capability development to support multiple missions can enable system capability level partnerships and further GER objectives. NASA has initiated efforts to develop AR&D/C sensors, that are directly applicable to GER. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. NASA's AR&D/C sensor development path could benefit the International Exploration Coordination Group (ISECG) and support the GER mission scenario by providing a common sensor suite upon which GER objectives could be achieved while