127 research outputs found
Preventing transition to turbulence: a viscosity stratification does not always help
In channel flows a step on the route to turbulence is the formation of
streaks, often due to algebraic growth of disturbances. While a variation of
viscosity in the gradient direction often plays a large role in
laminar-turbulent transition in shear flows, we show that it has, surprisingly,
little effect on the algebraic growth. Non-uniform viscosity therefore may not
always work as a flow-control strategy for maintaining the flow as laminar.Comment: 9 pages, 8 figure
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Tables of specifications and requirements for 1.0 MJ targets for 2010 ignition on NIF
Alignment of an x-ray imager line of sight in the National Ignition Facility (NIF) target chamber using a Diagnostic Instrument Manipulator (DIM) and Opposed Port Alignment System (OPAS)
Opposed port alignment system (OPAS): a commercial astronomical telescope modified for viewing the interior of the NIF target chamber
Abstract not provide
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Design and Use of a Novel Apparatus for Measuring Capsule Fill Hole Conductance
Description and results of a novel apparatus for determining the flow conductance through a laser drilled hole in a spherical shell for inertial confinement fusion experiments are described. The instrument monitors the pressure of an enclosed volume containing the laser pressure drilled capsule as air bleeds through the hole into the shell. From these measurements one obtains the conductance of the fill hole. This system has proven to be a valuable tool for verifying the conduct conductance into the capsule in a timely and nondestructive manner
Oral medicine acceptance in infants and toddlers: measurement properties of the caregiver-administered Children’s acceptance tool (CareCAT)
BACKGROUND: Developing age-appropriate medications remains a challenge in particular for the population of
infants and toddlers, as they are not able to reliably self-report if they would accept and consequently take an oral
medicine. Therefore, it is common to use caregivers as proxies when assessing medicine acceptance. The outcome
measures used in this research field differ and most importantly lack validation, implying a persisting gap in
knowledge and controversy in the field. The newly developed Caregiver-administered Children’s Acceptance Tool
(CareCAT) is based on a 5-point nominal scale, with descriptors of medication acceptance behavior. This crosssectional
study assessed the measurement properties of the tool with regards to the user’s understanding and its
intra- and inter-rater reliability.
METHODS: Participating caregivers were enrolled at a primary healthcare facility where their children (median age
6 months) had been prescribed oral antibiotics. Caregivers, trained observers and the tool developer observed and
scored on the CareCAT tool what behavior children exhibited when receiving the medicine (n = 104). The videorecords
of this process served as replicate observations (n = 69). After using the tool caregivers were asked to
explain their observations and the tool descriptors in their own words. The tool’s reliability was assessed by
percentage agreement and Cohen’s unweighted kappa coefficients of agreement for nominal scales.
RESULTS: The study found that caregivers using CareCAT had a satisfactory understanding of the tool’s descriptors.
Using its dichotomized scores the tool reliably was strong for acceptance behavior (agreement inter-rater 84–88%,
kappa 0.66–0.76; intra-rater 87–89%, kappa 0.68–0.72) and completeness of medicine ingestion (agreement inter-rater
82–86%, kappa 0.59–0.67; intra-rater 85–93%, kappa 0.50–0.70).
CONCLUSIONS: The CareCAT is a low-cost, easy-to-use and reliable instrument, which is relevant to assess acceptance
behavior and completeness of medicine ingestion, both of which are of significant importance for developing
age-appropriate medications in infants and toddlers
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Optimization of azimuthal uniformity of thermal conductance between AI TMP and Si cooling arms
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Fielding the NIF Cryogenic Ignition Target
The United States Department of Energy has embarked on a campaign to conduct credible fusion ignition experiments on the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in 2010. The target assembly specified for this campaign requires the formation of a deuterium/tritium (DT) fuel ice layer on the inside of a 2 millimeter diameter capsule positioned at the center of a 9 millimeter long by 5 millimeter diameter cylinder, called a hohlraum. The ice layer requires micrometer level accuracy and must be formed and maintained at temperatures below 19 K. At NIF shot time, the target must be positioned at the center of the NIF 10 meter diameter target chamber, aligned to the laser beam lines and held stable to less than 7 micrometers rms. We have completed the final design and are integrating the systems necessary to create, characterize and field the cryogenic target for ignition experiments. These designs, with emphasis on the challenges of fielding a precision cryogenic positioning system will be presented
Pharmacotherapeutic management of paediatric heart failure and ACE-I use patterns: A European survey
Objective To characterise heart failure (HF) maintenance
pharmacotherapy for children across Europe and
investigate how angiotensin-converting enzyme inhibitors
(ACE-I) are used in this setting.
Methods A Europe-wide web-based survey was
conducted between January and May 2015 among
European paediatricians dedicated to cardiology.
Results Out of 200-eligible, 100 physicians representing
100 hospitals in 27 European countries participated. All
participants reported prescribing ACE-I to treat dilated
cardiomyopathy-related HF and 97% in the context of
congenital heart defects; 87% for single ventricle physiology.
Twenty-six per cent avoid ACE-I i
Toward a Regulatory Pathway for the Use of in Silico Trials in The Ce Marking of Medical Devices
In Silico Trials methodologies will play a growing and fundamental role in the development and de-risking of new medical devices in the future. While the regulatory pathway for Digital Patient and Personal Health Forecasting solutions is clear, it is more complex for In Silico Trials solutions, and therefore deserves a deeper analysis. In this position paper, we investigate the current state of the art towards the regulatory system for in silico trials applied to medical devices while exploring the European regulatory system toward this topic. We suggest that the European regulatory system should start a process of innovation: in principle to limit distorted quality by different internal processes within notified bodies, hence avoiding that the more innovative and competitive companies focus their attention on the needs of other large markets, like the USA, where the use of such radical innovations is already rapidly developing
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