3,280 research outputs found
Structural modelling and testing of failed high energy pipe runs: 2D and 3D pipe whip
Copyright @ 2011 ElsevierThe sudden rupture of a high energy piping system is a safety-related issue and has been the subject of extensive study and discussed in several industrial reports (e.g. [2], [3] and [4]). The dynamic plastic response of the deforming pipe segment under the blow-down force of the escaping liquid is termed pipe whip. Because of the potential damage that such an event could cause, various geometric and kinematic features of this phenomenon have been modelled from the point of view of dynamic structural plasticity. After a comprehensive summary of the behaviour of in-plane deformation of pipe runs [9] and [10] that deform in 2D in a plane, the more complicated case of 3D out-of-plane deformation is discussed. Both experimental studies and modelling using analytical and FE methods have been carried out and they show that, for a good estimate of the “hazard zone” when unconstrained pipe whip motion could occur, a large displacement analysis is essential. The classical, rigid plastic, small deflection analysis (e.g. see [2] and [8]), is valid for estimating the initial failure mechanisms, however it is insufficient for describing the details and consequences of large deflection behaviour
Feeding interventions for growth and development in infants with cleft lip, cleft palate or cleft lip and palate.
BACKGROUND: Cleft lip and cleft palate are common birth defects, affecting about one baby of every 700 born. Feeding these babies is an immediate concern and there is evidence of delay in growth of children with a cleft as compared to those without clefting. In an effort to combat reduced weight for height, a variety of advice and devices are recommended to aid feeding of babies with clefts. OBJECTIVES: This review aims to assess the effects of these feeding interventions in babies with cleft lip and/or palate on growth, development and parental satisfaction. SEARCH STRATEGY: The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 27 October 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 4), MEDLINE via OVID (1950 to 27 October 2010), EMBASE via OVID (1980 to 27 October 2010), PsycINFO via OVID (1950 to 27 October 2010) and CINAHL via EBSCO (1980 to 27 October 2010). Attempts were made to identify both unpublished and ongoing studies. There was no restriction with regard to language of publication. SELECTION CRITERIA: Studies were included if they were randomised controlled trials (RCTs) of feeding interventions for babies born with cleft lip, cleft palate or cleft lip and palate up to the age of 6 months (from term). DATA COLLECTION AND ANALYSIS: Studies were assessed for relevance independently and in duplicate. All studies meeting the inclusion criteria were data extracted and assessed for validity independently by each member of the review team. Authors were contacted for clarification or missing information whenever possible. MAIN RESULTS: Five RCTs with a total of 292 babies, were included in the review. Comparisons made within the RCTs were squeezable versus rigid feeding bottles (two studies), breastfeeding versus spoon-feeding (one study) and maxillary plate versus no plate (two studies). No statistically significant differences were shown for any of the primary outcomes when comparing bottle types, although squeezable bottles were less likely to require modification. No difference was shown for infants fitted with a maxillary plate compared to no plate. However, there was some evidence of an effect on weight at 6 weeks post-surgery in favour of breastfeeding when compared to spoon-feeding (mean difference 0.47; 95% confidence interval 0.20 to 0.74). AUTHORS' CONCLUSIONS: Squeezable bottles appear easier to use than rigid feeding bottles for babies born with clefts of the lip and/or palate, however, there is no evidence of a difference in growth outcomes between the bottle types. There is weak evidence that breastfeeding is better than spoon-feeding following surgery for cleft. There was no evidence to suggest that maxillary plates assist growth in babies with clefts of the palate. No evidence was found to assess the use of any types of maternal advice and/or support for these babies
The Unusual Variability of the Large Magellanic Cloud Planetary Nebula RPJ 053059-683542
We present images and light curves of the bipolar Planetary Nebula RPJ
053059-683542 that was discovered in the Reid-Parker AAO/UKST H-alpha survey of
the Large Magellanic Cloud (LMC). The emission from this object appears
entirely nebular, with the central star apparently obscured by a central band
of absorption that bisects the nebula. The light curves, which were derived
from images from the SuperMACHO project at CTIO, showed significant, spatially
resolved variability over the period 2002 January through 2005 December.
Remarkably, the emission from the two bright lobes of the nebula vary either
independently, or similarly but with a phase lag of at least one year. The
optical spectra show a low level of nebular excitation, and only modest N
enrichment. Infrared photometry from the 2MASS and SAGE surveys indicates the
presence of a significant quantity of dust. The available data imply that the
central star has a close binary companion, and that the system has undergone
some kind of outburst event that caused the nebular emission to first brighten
and then fade. Further monitoring, high-resolution imaging, and detailed IR
polarimetry and spectroscopy would uncover the nature of this nebula and the
unseen ionizing source.Comment: Accepted for ApJ Letters; 6 page
Signposts: Resource for staff developers
This guide is for staff developers who work with new tertiary teachers, and provides guidelines on how to use 'Signposts: A professional development resource for new teaching staff in the tertiary sector'. It is the result of a project funded by the Ako Aotearoa Northern Hub
Confirmation of New Planetary Nebulae in the Large Magellanic Cloud
We present Hubble Space Telescope (HST) images of new planetary nebulae (PNe)
that were discovered in the Reid-Parker AAO/UKST H-alpha survey of the Large
Magellanic Cloud. These serendipitous observations from various HST programs
yield independent confirmations of 6 PNe; one other detected nebula may also be
a PN, and one appears to be a region of diffuse emission. The high resolution
HST archival images enable us to determine the physical sizes, the nebular
morphology, and related features of these new PNe in detail for the first time.
In a few cases we were also able to identify the central star, which was
impossible with the lower resolution, wide-field discovery data. The
confirmation of faint, extended halos surrounding many PNe in the RP catalog
must await the acquisition of new deep, high-resolution, narrow-band imagery.Comment: 6 figures. To appear in PASP, 2007 Januar
Decline in an Atlantic Puffin population : evaluation of magnitude and mechanisms
Funding: This study was funded annually by Fair Isle Bird Observatory Trust (www.fairislebirdobs.co.uk) with contributions from the Joint Nature Conservation Committee (jncc.defra.gov.uk). Funding was received from these two sources by Fair Isle Bird Observatory from 1986 to 2013. The Joint Nature Conservation Committee and Fair Isle Bird Observatory Trust supplied guidance on study design, data collection, analyses, preparation of the manuscript and the decision to publish.Peer reviewedPublisher PD
A New Population of Planetary Nebulae Discovered in the Large Magellanic Cloud (III): The Luminosity Function
Our previous identification and spectroscopic confirmation of 431 faint, new
planetary nebulae in the central 25 deg^2 region of the LMC permits us to now
examine the shape of the LMC Planetary Nebula Luminosity Function (PNLF)
through an unprecedented 10 magnitude range. The majority of our newly
discovered and previously known PNe were observed using the 2dF, multi-object
fibre spectroscopy system on the 3.9-m Anglo-Australian Telescope and the
FLAMES multi-object spectrograph on the 8-m VLT. We present reliable [OIII]5007
and H-beta flux estimates based on calibrations to well established PN fluxes
from previous surveys and spectroscopic standard stars. The bright cutoff (M*)
of the PNLF is found by fitting a truncated exponential curve to the bright end
of the PNLF over a 3.4 magnitude range. This cutoff is used to estimate a new
distance modulus of 18.46 to the LMC, in close agreement with previous PNLF
studies and the best estimates by other indicators. The bright end cutoff is
robust to small samples of bright PNe since significantly increased PN samples
do not change this fiducial. We then fit a truncated exponential curve directly
to the bright end of the function over a 6 magnitude range and test the curve's
ability to indicate the position of M*. Because of the significant increase in
the number of LMC PN, the shape of the PNLF is now examined in greater detail
than has previously been possible. Through cumulative functions, the new LMC
PNLF is compared to those from the SMC and a new deep local Galactic sample
revealing the effects of incompleteness. The new [OIII]5007 LMC PNLF is then
compared to our new H-beta LMC PNLF using calibrated and measured fluxes for
the same objects, revealing the effects of metallicity on the [OIII]5007 line.Comment: 28 pages, 24 figures. Accepted MNRA
Quantitative Assessment of the Risk of Release of Foot-and-Mouth Disease Virus via Export of Bull Semen from Israel
Various foot-and-mouth disease (FMD) virus strains circulate in the Middle East, causing frequent episodes of FMD outbreaks among Israeli livestock. Since the virus is highly resistant in semen, artificial insemination with contaminated bull semen may lead to the infection of the receiver cow. As a non-FMD-free country with vaccination, Israel is currently engaged in trading bull semen only with countries of the same status. The purpose of this study was to assess the risk of release of FMD virus through export of bull semen in order to estimate the risk for FMD-free countries considering purchasing Israeli bull semen. A stochastic risk assessment model was used to estimate this risk, defined as the annual likelihood of exporting at least one ejaculate of bull semen contaminated with viable FMD virus. A total of 45 scenarios were assessed to account for uncertainty and variability around specific parameter estimates and to evaluate the effect of various mitigation measures, such as performing a preexport test on semen ejaculates. Under the most plausible scenario, the annual likelihood of exporting bull semen contaminated with FMD virus had a median of 1.3 * 10(-7) for an export of 100 ejaculates per year. This corresponds to one infected ejaculate exported every 7 million years. Under the worst-case scenario, the median of the risk rose to 7.9 * 10(-5), which is equivalent to the export of one infected ejaculate every 12,000 years. Sensitivity analysis indicated that the most influential parameter is the probability of viral excretion in infected bulls
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