5,119 research outputs found
Ultraclean air systems and the claim that laminar airflow systems fail to prevent deep infections after total joint arthroplasty
The World Health Organization published guidelines in 2016 for preventing surgical site infections. The guidelines contained a conditional recommendation that laminar airflow (LAF) ventilation systems should not be used to reduce the risk of infection after total joint arthroplasty (TJA). This recommendation was largely based on a systematic review and meta-analysis of information from hospital infection surveillance registries. The recommendation contradicts information published in earlier major studies carried out by Charnley and the UK Medical Research Council (MRC). The first aim of this article is to revisit and explain the MRC study, and reply to criticisms of it. The second aim is to suggest reasons why some recent studies have failed to demonstrate that ultraclean air (UCA) systems reduce deep joint infection after TJA. It demonstrates that if a UCA system establishes average airborne concentrations of microbe-carrying particles (MCPs) <10/m , and preferably <1/m , then deep joint infection after TJA will be lower than in conventionally ventilated operating theatres
Inertial navigation systems for mobile robots
Cataloged from PDF version of article.A low-cost solid-state inertial navigation system
(INS) for mobile robotics applications is described. Error models
for the inertial sensors are generated and included in an Extended
Kalman Filter (EKF) for estimating the position and orientation
of a moving robot vehicle. Two Merent solid-state gyroscopes
have been evaluated for estimating the orientation of the robot.
Performance of the gyroscopes with error models is compared to
the performance when the error models are excluded from the
system. The results demonstrate that without error compensation,
the error in orientation is between 5-15"/min but can be improved
at least by a factor of 5 if an adequate error model is supplied.
Siar error models have been developed for each axis of a solid-state triaxial accelerometer and for a conducting-bubble tilt sensor which may also be used as a low-cost accelerometer. Linear
position estimation with information from accelerometers and tilt sensors is more susceptible to errors due to the double integration
process involved in estimating position. With the system described
here, the position drift rate is 1-8 cds, depending on the frequency
of acceleration changes. An integrated inertial platform
consisting of three gyroscopes, a triaxial accelerometer and two
tilt sensors is described. Results from tests of this platform on a large outdoor mobile robot system are described and compared to
the results obtained from the robot's own radar-based guidance
system. Like all inertial systems, the platform requires additional
information from some absolute position-sensing mechanism to
overcome long-term drift. However, the results show that with
careful and detailed modeling of error sources, low-cost inertial
sensing systems can provide valuable orientation and position
information particularly for outdoor mobile robot applications
Evaluation of solid-state gyroscope for robotics applications
Cataloged from PDF version of article.he evaluation of a low-cost solid-state gyroscope
for robotics applications is described. An error model for the
sensor is generated and included in a Kalman filter for estimating
the orientation of a moving robot vehicle. Orientation eshation
with the error model is compared to the performance when the
error model is excluded from the system. The results demonstrate
that without error compensation, the error in localization is
between 5-15"/min but can be improved at least by a factor
of 5 if an adequate error model is supplied. Like all inertial
systems, the platform requires additional information from some
absolute position-sensing mechanism to overcome long-term drift.
However, the results show that with careful and detailed modeling
of error sources, inertial sensors can provide valuable orientation
information for mobile robot applications
Bitou bush and boneseed eradication and containment in Australia
Bitou bush and boneseed (Chrysanthemoides monilifera subsp. rotundata (DC.) T.Norl. and C. monilifera subsp. monilifera (L.) T.Norl., respectively) are highly invasive environmental weeds that pose a serious threat to Australia’s natural ecosystems and biota. Bitou bush threatens coastal plant communities in New South Wales (NSW), eastern Victoria and southeast Queensland (Qld), while boneseed threatens inland and coastal native plant communities across NSW, South Australia (SA), Tasmania, Victoria, and Western Australia (WA). Over 200 plant species and ecological communities in Australia are negatively impacted by these weeds (ARMCANZ et al. 2000, DEC 2006) and over 15% (approx. 120 million ha) of Australia is susceptible to invasion (see maps in Weiss et al 2008).
In 2000, the National Bitou Bush and Boneseed Strategic Plan (ARMCANZ et al. 2000) was approved as part of the Commonwealth’s Weeds of National Significance initiative. A key goal of this plan is to prevent the spread of bitou bush and boneseed in Australia. A national program sponsored by the Australian Government and the affected states has resulted in the development of national containment and eradication zones that prevent the spread of bitou bush and boneseed. This paper presents an overview of these bitou bush and boneseed containment and eradication programs
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