3,474 research outputs found
Open-ocean interior moored sensor turbulence estimates, below a Meddy
A one-year time series of moored high-resolution temperature T-sensor data
from 1455 m depth on a 3900 m long line in about 5300 m of water in the
NE-Atlantic Canary Basin are dominated by salinity (over-)compensated
intrusions arising from the effects of Mediterranean outflow waters, which are
commonly organized as Meddies. During the passage of a Meddy-core above the
T-sensors, no intrusions were observed, thereby making it possible to use the
temperature records to quantify turbulence parameters. The present data show
that these ocean-interior turbulence estimates are from short-lived (less than
0.5 h) rather intense overturning cells with vertical scales of <5 m. Because
the turbulence inertial subrange is found to extend into the internal wave
band, the overturns are predominantly driven by shear associated with inertial
currents. Kinetic energy, current shear and temperature variance peak at
sub-inertial frequencies during the Meddy passage, suggesting wave trapping in
the warm anti-cyclonic eddy and/or weakly stratified layers. The observations
further show that internal wave displacements are coherent over vertical scales
of up to 40 m during the presence of the Meddy compared with vertical coherence
scales of less than 25 m during the more common no-Meddy conditions of double
diffusion intrusions.Comment: 32 pages, 9 figure
E-voting discourses in the UK and the Netherlands
A qualitative case study of the e-voting discourses in the UK and the Netherlands was performed based on the theory of strategic niche management. In both countries, eight e-voting experts were interviewed on their expectations, risk estimations, cooperation and learning experiences. The results show that differences in these variables can partly explain the variations in the embedding of e-voting in the two countries, from a qualitative point of view
Temperature statistics above a deep-ocean sloping boundary
We present a detailed analysis of the temperature statistics in an
oceanographic observational dataset. The data are collected using a moored
array of thermistors, 100 m tall and starting 5 m above the bottom, deployed
during four months above the slopes of a Seamount in the north-eastern Atlantic
Ocean. Turbulence at this location is strongly affected by the semidiurnal
tidal wave. Mean stratification is stable in the entire dataset. We compute
structure functions, of order up to 10, of the distributions of temperature
increments. Strong intermittency is observed, in particular, during the
downslope phase of the tide, and farther from the solid bottom. In the lower
half of the mooring during the upslope phase, the temperature statistics are
consistent with those of a passive scalar. In the upper half of the mooring,
the temperature statistics deviate from those of a passive scalar, and evidence
of turbulent convective activity is found. The downslope phase is generally
thought to be more shear-dominated, but our results suggest on the other hand
that convective activity is present. High-order moments also show that the
turbulence scaling behaviour breaks at a well-defined scale (of the order of
the buoyancy length scale), which is however dependent on the flow state (tidal
phase, height above the bottom). At larger scales, wave motions are dominant.
We suggest that our results could provide an important reference for laboratory
and numerical studies of mixing in geophysical flows.Comment: 22 pages, 10 figures, 3 tables. Accepted versio
Sleeping on a problem: the impact of sleep disturbance on intensive care patients - a clinical review
Sleep disturbance is commonly encountered amongst intensive care patients and has significant psychophysiological effects, which protract recovery and increases mortality. Bio-physiological monitoring of intensive care patients reveal alterations in sleep architecture, with reduced sleep quality and continuity. The etiological causes of sleep disturbance are considered to be multifactorial, although environmental stressors namely, noise, light and clinical care interactions have been frequently cited in both subjective and objective studies. As a result, interventions are targeted towards modifiable factors to ameliorate their impact. This paper reviews normal sleep physiology and the impact that sleep disturbance has on patient psychophysiological recovery, and the contribution that the clinical environment has on intensive care patients' sleep
Innovative lignocellulosic cropping systems in Europe: combining knowledge from several EU-projects.
Innovative lignocellulosic cropping systems in Europe: combining knowledge from several EU-projects.
The biomass demand for the use as both renewable energy source and raw material for the biotechnology industry is increasing. Simultaneously, the supply of biomass is requested to become more costcompetitive. Innovative solutions for cost-effective biomass production should also avoid indirect land use changes and direct negative environmental effects. The main aim of this study is to identify the most promising innovative lignocellulosic cropping systems regarding environmental sustainability as well as social acceptance for different cost scenarios and different regions in Europe. To gather innovative cropping knowledge from around Europe ADVANCEFUEL organized a workshop. Participating Horizon 2020 projects presenting innovative approaches on lignocellulosic cropping systems included: FORBIO, MAGIC, BECOOL, LIBBIO, GRACE, and SEEMLA. Data was collected from field studies of the participating projects prior to the workshop and later presented in an aggregated way as a basis for discussions. This approach incorporates the knowledge gained in over 60 study cases conducted in 12 different countries. Under these study cases, 16 different lignocellulosic crops were covered. This field based knowledge can be used to validate spatial assessments of sustainable biomass production potentials in Europe
AABW-transport variation and its effect on internal wave motions between top and bottom of the Puerto Rico Trench
Slow subinertial variations in Antarctic Bottom Water (AABW) are investigated interacting with internal waves and associated turbulent mixing in the Puerto Rico Trench (PRT), northwest Atlantic. Just below the PRT\u27s top at 5,500 m, a deep-sea mooring was deployed for 14 months. Around 6,100 m, the line held a 200 m long string of 101 high-resolution temperature sensors and a current meter. Around 8,250 m, a similar string held 102 sensors, of which the lowest was 9 m above the bottom. As was measured with shipborne conductivity-temperature-depth profiling down to 7,150 m, PRT waters are very weakly stratified, with local mean buoyancy frequency equaling 1β1.7 times the semidiurnal tidal frequency. The observations show alternating quiescent and relatively turbulent periods that correspond with relatively cooler and warmer AABW, respectively. Over the 2,100 m distance between the two temperature strings, only semidiurnal tidal variations significantly correlate with an average phase difference of 90Β° (3 h) for the entire recording period. This suggests a dominant baroclinic rather than a barotropic coupling. During quiescent periods, the vertical internal wave scale is rather small with out-of-phase tidal motions between the two data sets and vertical excursions of 40 m. During turbulent periods, internal wave motions at all frequencies are close to in phase between the two data sets, suggesting fast vertical propagation with excursions exceeding 200 m. Increased subinertial energy levels, probably reflecting trapped internal waves, are found near the bottom during such periods. It is suggested that internal wave turbulence dominates the deep-sea transport of heat and suspended materials over the entire PRT height and possibly beyond
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