448 research outputs found
Accuracy of Transillumination in the Recognition of Pneumothorax and Pneumomediastinum in the Neonate
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66508/2/10.1177_000992287701600404.pd
Selection & development of short-term project team members:developmental stability as an indicator of interpersonal skills
Short-term project teams do not have the advantage of prior performance or long-term membership to facilitate development of effective team performance. Research suggests interpersonal skills are crucial to success but this is under researched longitudinally. Evolutionary psychology can provide a lens to explain how people develop differing levels of interpersonal skills via the relationship between fluctuating asymmetry and pro-social behaviours. This research aims to investigate the relationship between fluctuating asymmetry and interpersonal skills, the impact of training and to further the evolutionary psychology field by embedding research in a real-world context as opposed to solely in laboratory or student settings
Climate and basin drivers of seasonal river water temperature dynamics
Stream water temperature is a key control of many river processes (e.g. ecology, biogeochemistry, hydraulics) and services (e.g. power plant cooling, recreational use). Consequently, the effect of climate change and variability on stream temperature is a major scientific and practical concern. This paper aims (1) to improve the understanding of large-scale spatial and temporal variability in climate–water temperature associations, and (2) to assess explicitly the influence of basin properties as modifiers of these relationships. A dataset was assembled including six distinct modelled climatic variables (air temperature, downward short-wave and long-wave radiation, wind speed, specific humidity, and precipitation) and observed stream temperatures for the period 1984–2007 at 35 sites located on 21 rivers within 16 basins (Great Britain geographical extent); the study focuses on broad spatio-temporal patterns, and hence was based on 3-month-averaged data (i.e. seasonal). A wide range of basin properties was derived. Five models were fitted (all seasons, winter, spring, summer, and autumn). Both site and national spatial scales were investigated at once by using multi-level modelling with linear multiple regressions. Model selection used multi-model inference, which provides more robust models, based on sets of good models, rather than a single best model. Broad climate–water temperature associations common to all sites were obtained from the analysis of the fixed coefficients, while site-specific responses, i.e. random coefficients, were assessed against basin properties with analysis of variance (ANOVA). All six climate predictors investigated play a role as a control of water temperature. Air temperature and short-wave radiation are important for all models/seasons, while the other predictors are important for some models/seasons only. The form and strength of the climate–stream temperature association vary depending on season and on water temperature. The dominating climate drivers and physical processes may change across seasons and across the stream temperature range. The role of basin permeability, size, and elevation as modifiers of the climate–water temperature associations was confirmed; permeability has the primary influence, followed by size and elevation. Smaller, upland, and/or impermeable basins are the most influenced by atmospheric heat exchanges, while larger, lowland and permeable basins are the least influenced. The study showed the importance of accounting properly for the spatial and temporal variability of climate–stream temperature associations and their modification by basin properties
Underexpanded gas jets of Mach 2: the changing physical structure and power transmission
Supersonic jets with excess gas pressure are associated with many phenomena including radio galaxies, protostars, volcanic plumes, rocket exhausts, and champagne cork popping. Some common properties are derived here based on steady uniform hydrodynamic flow from a circular orifice. We present a systematic numerical study over a wide range of parameters for Mach 2 jets, concentrating on simulations of jets with pressures exceeding the ambient pressure. With cylindrical symmetry, we show how the location of the stand-off and following downstream shocks depend not only on the overpressure but also on the density due to a feedback loop, which results in an oscillatory flow pattern. We conclude that rapidly varying and gradually evolving shock patterns arise even from steady uniform jets. This can take the form of turbulent plumes at high overpressures and regular oscillations at low overpressures. We identify where this screeching contributes to noise and sound wave generation, which may aid the regulation of star and galaxy formation. However, the main effect for such low Mach number jets is to drive a circulatory motion in which the ambient medium is driven out along the axial direction while mass and energy flow laterally inwards, setting up a large advection pattern. Once the initial bow shock has propagated out, the noise from the jet is insufficient to significantly alter the environment. High Mach number jets do not follow these conclusions and will be treated separately
Ralgro-implanted bulls: Performance, carcass characteristics, longissimus palatability and carcass electrical stimulation
Twenty of 40 Angus bulls were implanted
(I) five times with 36 mg of Ralgro| at average
intervals of 106 d, beginning near birth. All
bulls and their dams were on bluestem pasture
initially and, at an average age of 320 d bulls
were fed a concentrate diet until they were
slaughtered, weighing either 454 or 499 kg. One
side of each carcass was electrically stimulated.
Average daily gain and feed efficiency of I
bulls improved 6.5 to 10.4% and 7.9 to 8.1%,
respectively, depending upon the end point
comparison with nonimplanted (NI) bulls. Implanted
bulls attained their slaughter weights 42
d sooner than did NI bulls. Implantation
decreased (P<.05) penis weight and length,
testicle weight, volume and density, but did not
affect (P>.05) seminal vesicle and pituitary
weights. Carcasses from I bulls had more
(P<.05) skeletal ossification and were fatter
than carcasses from NI bulls. Marbling scores,
quality grades and longissimus cooking losses
and juiciness scores were not affected (P>.05)
by implantation. Taste panel flavor intensity
and detectable connective tissue scores were
higher (P<.05) for steaks from I bulls than
from NI bulls. Longissimus steak tenderness
evaluations were higher (P<.05) for both I
slaughter groups than for the NI light-weight group and were higher (P<.05) for the I lightweight
group than for the NI heavy-weight
group. Longissimus tenderness tended (P = .11)
to be higher for steaks from the I heavy-weight
group than those from the NI heavy-weight
group. Electrical stimulation produced (P<.05)
a softer, coarser textured lean, but it did not
affect lean color, marbling or quality grade.
Steaks from electrically stimulated sides tended
to have higher (P = .09) myofibrillar tenderness
scores and lower (P = .06) flavor scores than
steaks from nonstimulated sides
Constraining dark energy fluctuations with supernova correlations
We investigate constraints on dark energy fluctuations using type Ia
supernovae. If dark energy is not in the form of a cosmological constant, that
is if the equation of state is not equal to -1, we expect not only temporal,
but also spatial variations in the energy density. Such fluctuations would
cause local variations in the universal expansion rate and directional
dependences in the redshift-distance relation. We present a scheme for relating
a power spectrum of dark energy fluctuations to an angular covariance function
of standard candle magnitude fluctuations. The predictions for a
phenomenological model of dark energy fluctuations are compared to
observational data in the form of the measured angular covariance of Hubble
diagram magnitude residuals for type Ia supernovae in the Union2 compilation.
The observational result is consistent with zero dark energy fluctuations.
However, due to the limitations in statistics, current data still allow for
quite general dark energy fluctuations as long as they are in the linear
regime.Comment: 18 pages, 6 figures, matches the published versio
Pharmacokinetics and Safety of Micafungin in Infants Supported With Extracorporeal Membrane Oxygenation
Candida is a leading cause of infection in infants on extracorporeal membrane oxygenation (ECMO). Optimal micafungin dosing is unknown in this population because ECMO can alter drug pharmacokinetics (PK)
Macroinvertebrate community responses to river impoundment at multiple spatial scales
River impoundment by the construction of dams potentially modifies a wide range of abiotic and biotic factors in lotic ecosystems and is considered one of the most significant anthropogenic impacts on rivers globally. The past two decades have witnessed a growing body of research centred on quantifying the effects of river impoundment, with a focus on mitigating and managing the effects of individual large dams. This study presents a novel multi-scale comparison of paired downstream and control sites associated with multiple water supply reservoirs (n = 80) using a spatially extensive multi-year dataset. Macroinvertebrate community structure and indices were analysed in direct association with spatial (e.g. region) and temporal variables (e.g. season) to identify consistent patterns in ecological responses to impoundment. Macroinvertebrate communities at monitoring sites downstream of water supply reservoirs differed significantly from those at control sites at larger spatial scales, both in terms of community structure and taxa richness. The effect was most significant at the regional scale, while biogeographical factors appeared to be important drivers of community differences at the national scale. Water supply reservoirs dampened natural seasonal patterns in community structure at sites downstream of impoundments. Generally, taxonomic richness was higher and %EPT richness lower at downstream sites. Biomonitoring indices used for river management purposes were able to detect community differences, demonstrating their sensitivity to river regulation activities. The results presented improve our understanding of the spatially extensive and long-term effects of water supply reservoirs on instream communities and provide a basis for the future implementation of mitigation measures on impounded rivers and heavily modified waterbodies
The identification of hydrological indices for the characterization of macroinvertebrate community response to flow regime variability
The importance of flow regime variability for maintaining ecological functioning and integrity of river ecosystems has been firmly established in both natural and anthropogenically modified systems. River flow regimes across lowland catchments in eastern England are examined using 47 variables, including those derived using the Indicators of Hydrologic Alteration (IHA) software. A principal component analysis method was used to identify redundant hydrological variables and those that best characterized the hydrological series (1986–2005). A small number of variables (<6) characterized up to 95% of the statistical variability in the flow series. The hydrological processes and conditions that the variables represent were found to be significant in structuring the in-stream macroinvertebrate community Lotic-invertebrate Index for Flow Evaluation (LIFE) scores at both the family and species levels. However, hydrological variables only account for a relatively small proportion of the total ecological variability (typically <10%). The research indicates that a range of other factors, including channel morphology and anthropogenic modification of in-stream habitats, structure riverine macroinvertebrate communities in addition to hydrology. These factors need to be considered in future environmental flow studies to enable the characterization of baseline/reference conditions for management and restoration purposes
Vibrational Study of 13C-enriched C60 Crystals
The infrared (IR) spectrum of solid C60 exhibits many weak vibrational modes.
Symmetry breaking due to 13C isotopes provides a possible route for optically
activating IR-silent vibrational modes. Experimental spectra and a
semi-empirical theory on natural abundance and 13C-enriched single crystals of
C60 are presented. By comparing the experimental results with the theoretical
results, we exclude this isotopic activation mechanism from the explanation for
weakly active fundamentals in the spectra.Comment: Accepted for Phys. Rev. B, typeset in REVTEX v3.0 in LaTeX.
Postscript file including figures is available at
http://insti.physics.sunysb.edu/~mmartin/papers/c13twocol2.ps File with
figures will be e-mailed by reques
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