858 research outputs found
Can treatment success with 5% lidocaine medicated plaster be predicted in cancer pain with neuropathic components or trigeminal neuropathic pain?
An expert group of 40 pain specialists from 16 countries performed a first assessment of the value of predictors for treatment success with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain. Results were based on the retrospective analysis of 68 case reports (sent in by participants in the 4 weeks prior to the conference) and the practical experience of the experts. Lidocaine plaster treatment was mostly successful for surgery or chemotherapy-related cancer pain with neuropathic components. A dose reduction of systemic pain treatment was observed in at least 50% of all cancer pain patients using the plaster as adjunct treatment; the presence of allodynia, hyperalgesia or pain quality provided a potential but not definitively clear indication of treatment success. In trigeminal neuropathic pain, continuous pain, severe allodynia, hyperalgesia, or postherpetic neuralgia or trauma as the cause of orofacial neuropathic pain were perceived as potential predictors of treatment success with lidocaine plaster. In conclusion, these findings provide a first assessment of the likelihood of treatment benefits with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain and support conducting large, well-designed multicenter studies
Localness of energy cascade in hydrodynamic turbulence, II. Sharp spectral filter
We investigate the scale-locality of subgrid-scale (SGS) energy flux and
inter-band energy transfers defined by the sharp spectral filter. We show by
rigorous bounds, physical arguments and numerical simulations that the spectral
SGS flux is dominated by local triadic interactions in an extended turbulent
inertial-range. Inter-band energy transfers are also shown to be dominated by
local triads if the spectral bands have constant width on a logarithmic scale.
We disprove in particular an alternative picture of ``local transfer by
nonlocal triads,'' with the advecting wavenumber mode at the energy peak.
Although such triads have the largest transfer rates of all {\it individual}
wavenumber triads, we show rigorously that, due to their restricted number,
they make an asymptotically negligible contribution to energy flux and
log-banded energy transfers at high wavenumbers in the inertial-range. We show
that it is only the aggregate effect of a geometrically increasing number of
local wavenumber triads which can sustain an energy cascade to small scales.
Furthermore, non-local triads are argued to contribute even less to the
space-average energy flux than is implied by our rigorous bounds, because of
additional cancellations from scale-decorrelation effects. We can thus recover
the -4/3 scaling of nonlocal contributions to spectral energy flux predicted by
Kraichnan's ALHDIA and TFM closures. We support our results with numerical data
from a pseudospectral simulation of isotropic turbulence with
phase-shift dealiasing. We conclude that the sharp spectral filter has a firm
theoretical basis for use in large-eddy simulation (LES) modeling of turbulent
flows.Comment: 42 pages, 9 figure
A set of diagnostic for evaluating chemistry-climate models in the extratropical tropopause region
Physical Response of the York River Estuary to Hurricane Isabel
After making landfall on the North Carolina coast on the morning of 18 September 2003, Category 2 Hurricane Isabel tracked northward parallel to and slightly west of the Chesapeake Bay. At Gloucester Point, near the mouth of the York River estuary, strong onshore winds with speeds in excess of 20 m⋅s-1 persisted for over 12 hours and peak winds reached over 40 m⋅s-1, causing a sustained up-estuary wind stress. Storm surge exceeded 2 m throughout most of the lower Chesapeake Bay. A 600 kHz acoustic Doppler current profiler (ADCP), deployed at a depth of 8.5 m off Gloucester Point, provided high-quality data on waves, storm surge, currents, and acoustic backscatter throughout the water column before, during, and after the storm. Pressure and salinity sensors at three additional sites further up the estuary provided information on water surface slope and saltwater excursion up the estuary. A first-order estimate of three terms of the along-channel momentum equation (barotropic pressure gradient, acceleration, and friction) showed that the pressure gradient appeared to be balanced by the wind stress and the acceleration during the storm. The storm’s path and slow speed were the primary causes of the extremely high storm surge relative to past storms in the area.https://scholarworks.wm.edu/vimsbooks/1001/thumbnail.jp
Localness of energy cascade in hydrodynamic turbulence, I. Smooth coarse-graining
We introduce a novel approach to scale-decomposition of the fluid kinetic
energy (or other quadratic integrals) into band-pass contributions from a
series of length-scales. Our decomposition is based on a multiscale
generalization of the ``Germano identity'' for smooth, graded filter kernels.
We employ this method to derive a budget equation that describes the transfers
of turbulent kinetic energy both in space and in scale. It is shown that the
inter-scale energy transfer is dominated by local triadic interactions,
assuming only the scaling properties expected in a turbulent inertial-range. We
derive rigorous upper bounds on the contributions of non-local triads,
extending the work of Eyink (2005) for low-pass filtering. We also propose a
physical explanation of the differing exponents for our rigorous upper bounds
and for the scaling predictions of Kraichnan (1966,1971). The faster decay
predicted by Kraichnan is argued to be the consequence of additional
cancellations in the signed contributions to transfer from non-local triads,
after averaging over space. This picture is supported by data from a
pseudospectral simulation of Navier-Stokes turbulence with phase-shift
dealiasing.Comment: 26 pages, 4 figure
Effect of filter type on the statistics of energy transfer between resolved and subfilter scales from a-priori analysis of direct numerical simulations of isotropic turbulence
The effects of different filtering strategies on the statistical properties
of the resolved-to-sub-filter scale (SFS) energy transfer are analyzed in
forced homogeneous and isotropic turbulence. We carry out a priori analyses of
statistical characteristics of SFS energy transfer by filtering data obtained
from direct numerical simulations (DNS) with up to grid points as a
function of the filter cutoff scale. In order to quantify the dependence of
extreme events and anomalous scaling on the filter, we compare a sharp Fourier
Galerkin projector, a Gaussian filter and a novel class of Galerkin projectors
with non-sharp spectral filter profiles. Of interest is the importance of
Galilean invariance and we confirm that local SFS energy transfer displays
intermittency scaling in both skewness and flatness as a function of the cutoff
scale. Furthermore, we quantify the robustness of scaling as a function of the
filtering type
Report of the 1988 2-D Intercomparison Workshop, chapter 3
Several factors contribute to the errors encountered. With the exception of the line-by-line model, all of the models employ simplifying assumptions that place fundamental limits on their accuracy and range of validity. For example, all 2-D modeling groups use the diffusivity factor approximation. This approximation produces little error in tropospheric H2O and CO2 cooling rates, but can produce significant errors in CO2 and O3 cooling rates at the stratopause. All models suffer from fundamental uncertainties in shapes and strengths of spectral lines. Thermal flux algorithms being used in 2-D tracer tranport models produce cooling rates that differ by as much as 40 percent for the same input model atmosphere. Disagreements of this magnitude are important since the thermal cooling rates must be subtracted from the almost-equal solar heating rates to derive the net radiative heating rates and the 2-D model diabatic circulation. For much of the annual cycle, the net radiative heating rates are comparable in magnitude to the cooling rate differences described. Many of the models underestimate the cooling rates in the middle and lower stratosphere. The consequences of these errors for the net heating rates and the diabatic circulation will depend on their meridional structure, which was not tested here. Other models underestimate the cooling near 1 mbar. Suchs errors pose potential problems for future interactive ozone assessment studies, since they could produce artificially-high temperatures and increased O3 destruction at these levels. These concerns suggest that a great deal of work is needed to improve the performance of thermal cooling rate algorithms used in the 2-D tracer transport models
Radiative forcing in the 21st century due to ozone changes in the troposphere and the lower stratosphere
Radiative forcing due to changes in ozone is expected for the 21st century. An assessment on changes in the tropospheric oxidative state through a model intercomparison ("OxComp'') was conducted for the IPCC Third Assessment Report (IPCC-TAR). OxComp estimated tropospheric changes in ozone and other oxidants during the 21st century based on the "SRES'' A2p emission scenario. In this study we analyze the results of 11 chemical transport models (CTMs) that participated in OxComp and use them as input for detailed radiative forcing calculations. We also address future ozone recovery in the lower stratosphere and its impact on radiative forcing by applying two models that calculate both tropospheric and stratospheric changes. The results of OxComp suggest an increase in global-mean tropospheric ozone between 11.4 and 20.5 DU for the 21st century, representing the model uncertainty range for the A2p scenario. As the A2p scenario constitutes the worst case proposed in IPCC-TAR we consider these results as an upper estimate. The radiative transfer model yields a positive radiative forcing ranging from 0.40 to 0.78 W m(-2) on a global and annual average. The lower stratosphere contributes an additional 7.5-9.3 DU to the calculated increase in the ozone column, increasing radiative forcing by 0.15-0.17 W m(-2). The modeled radiative forcing depends on the height distribution and geographical pattern of predicted ozone changes and shows a distinct seasonal variation. Despite the large variations between the 11 participating models, the calculated range for normalized radiative forcing is within 25%, indicating the ability to scale radiative forcing to global-mean ozone column change
Forecasts and assimilation experiments of the Antarctic ozone hole 2008
The 2008 Antarctic ozone hole was one of the largest and most long-lived in
recent years. Predictions of the ozone hole were made in near-real time
(NRT) and hindcast mode with the Integrated Forecast System (IFS) of the
European Centre for Medium-Range Weather Forecasts (ECMWF). The forecasts
were carried out both with and without assimilation of satellite
observations from multiple instruments to provide more realistic initial
conditions. Three different chemistry schemes were applied for the
description of stratospheric ozone chemistry: (i) a linearization of the
ozone chemistry, (ii) the stratospheric chemical mechanism of the Model of
Ozone and Related Chemical Tracers, version 3, (MOZART-3) and (iii) the
relaxation to climatology as implemented in the Transport Model, version 5,
(TM5). The IFS uses the latter two schemes by means of a two-way coupled
system. Without assimilation, the forecasts showed model-specific
shortcomings in predicting start time, extent and duration of the ozone
hole. The assimilation of satellite observations from the Microwave Limb
Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Solar
Backscattering Ultraviolet radiometer (SBUV-2) and the SCanning Imaging
Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) led to a
significant improvement of the forecasts when compared with total columns
and vertical profiles from ozone sondes. The combined assimilation of
observations from multiple instruments helped to overcome limitations of the
ultraviolet (UV) sensors at low solar elevation over Antarctica. The
assimilation of data from MLS was crucial to obtain a good agreement with
the observed ozone profiles both in the polar stratosphere and troposphere.
The ozone analyses by the three model configurations were very similar
despite the different underlying chemistry schemes. Using ozone analyses as
initial conditions had a very beneficial but variable effect on the
predictability of the ozone hole over 15 days. The initialized forecasts
with the MOZART-3 chemistry produced the best predictions of the increasing
ozone hole whereas the linear scheme showed the best results during the
ozonehole closure
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