98 research outputs found
The practice of palliative sedation in the Netherlands after the launch of the national guideline
Palliative sedation is a medical intervention aimed at relieving intractable suff ering by inducing
decreased awareness of symptoms. It is typically considered a palliative option for
patients suff ering unbearably in the last days of life. The estimated frequency of palliative
sedation varies considerably in scientifi c literature, partly due to diff erences in defi nition
and research setting and diff erences in terminology. Whereas in the English medical scientifi
c literature the fi rst descriptions of palliative sedation referred to ‘terminal sedation’,
in Dutch medical literature palliative sedation was fi rst described as ‘deep sedation in the
dying phase’. Although terminology still varies – e.g. continuous deep sedation6, continuous
sedation until death, continuous deep sedation until death, continuous sedation at
the end of life, palliative sedation at the end of life, palliative sedation therapy, palliative
sedation to unconsciousness, terminal sedation, continuous palliative sedation – the
most frequently used general term for this treatment in the literature nowadays is palliative
sedation
What do near-term observations tell us about long-term developments in greenhouse gas emissions? A letter
Long-term scenarios developed by integrated assessment models are used in climate research to provide an indication of plausible long-term emissions of greenhouse gases and other radiatively active substances based on developments in the global energy system, land-use and the emissions associated with these systems The phenomena that determine these long-term developments (several decades or even centuries) are very different than those that operate on a shorter time-scales (a few years) Nevertheless, in the literature, we still often find direct comparisons between short-term observations and long-term developments that do not take into account the differing dynamics over these time scales In this letter, we discuss some of the differences between the factors that operate in the short term and those that operate in the long term We use long-term historical emissions trends to show that short-term observations are very poor indicators of long-term future emissions developments Based on this, we conclude that the performance of long-term scenarios should be evaluated against the appropriate, corresponding long-term variables and trends The research community may facilitate this by developing appropriate data sets and protocols that can be used to test the performance of long-term scenarios and the models that produce the
The effect of annealing time on the structural and optical properties of ZnAl2O4:0.01% Cr3+ nanophosphor prepared via sol-gel method
Zinc aluminate (ZnAl2O4) host and 0.01% Cr3+ doped were successfully prepared using the sol–gel method. The annealing time (AT) was varied in the range of 0.5–19 h. The x-ray diffraction results showed that the AT does not affect the crystal structure of the prepared powders. Scanning electron microscopy (SEM) results showed that the morphology of the prepared nanophosphors was influenced by the AT. Energy dispersive x-ray spectroscopy (EDS) confirmed the homogeneous distribution of the constituent elements. Transmission electron microscopy (TEM) suggested that the average crystallites sizes of the ZnAl2O4 to be ~20 nm. Ultraviolet–visible (UV–Vis) spectroscopy results revealed that the bandgap (E g) of the prepared nanophosphor can be tuned by varying the AT. The emission peak at 390 nm is attributed to the intrinsic defects within the host material bandgap. The emission peak at 572 nm is attributed to both contribution from the host and Cr3+ (4T1 → 4A2) transition. The maximum PL intensity was observed from the samples annealed for 3 h. The International Commission on Illumination (CIE) chromaticity diagram showed a slight shift on the blue emission with an increase in AT.http://link.springer.com/journal/116642019-01-30hj2018Physic
Regge description of two pseudoscalar meson production in antiproton-proton annihilation
A Regge-inspired model is used to discuss the hard exclusive two-body
hadronic reactions (pbar p ----> pi+ pi-, pi0 pi0, K+ K-, Kbar0 K0) for the
FAIR facility project at GSI with the Panda detector. The comparison between
the differential cross sections predictions and the available data is shown to
determine the values of the few parameters of the model.Comment: 9 pages, 13 figure
Semileptonic decay constants of octet baryons in the chiral quark-soliton model
Based on the recent study of the magnetic moments and axial constants within
the framework of the chiral quark-soliton model, we investigate the baryon
semileptonic decay constants and . Employing the
relations between the diagonal transition matrix elements and off-diagonal ones
in the vector and axial-vector channels, we obtain the ratios of baryon
semileptonic decay constants and . The ratio is also
discussed and found that the value predicted by the present model naturally
lies between that of the Skyrme model and that of the nonrelativistic quark
model. The singlet axial constant can be expressed in terms of the
ratio and in the present model and turns out to be small. The
results are compared with available experimental data and found to be in good
agreement with them. In addition, the induced pseudotensor coupling constants
are calculated, the SU(3) symmetry breaking being considered. The
results indicate that the effect of SU(3) symmetry breaking might play an
important role for some decay modes in hyperon semileptonic decay.Comment: 16 pages, RevTeX is used. No figure. Accepted for publication in
Phys. Rev.
Additional evidence on serological correlates of protection against measles: An observational cohort study among once vaccinated children exposed to measles
To assess correlates of protection against measles and against subclinical measles virus (MV) infection, we recruited once-vaccinated children from geographic regions associated with increased MV circulation and/or at schools with low vaccination coverage in the Netherlands. Paired blood samples were collected shortly after onset of the measles outbreak and after the outbreak. A questionnaire was used to document the likelihood of exposure to MV and occurrence of measles-like symptoms. All blood samples were tested for MV-specific antibodies with five different assays. Correlates of protection were assessed by considering the lowest neutralizing antibody levels in children without MV infection, and by ROC analyses. Among 91 participants, two seronegative children (2%) developed measles, and an additional 19 (23%) experienced subclinical MV infection. The correlate of protection against measles was lower than 0.345 IU/mL. We observed a decreasing attack rate of subclinical MV infection with increasing levels of specific antibodies until 2.1 IU/mL, above which no subclinical MV infections were detected. The ROC analyses found a correlate of protection of 1.71 IU/mL (95% CI 1.01–2.11) for subclinical MV infection. Our correlates of protection were consistent with previous estimates. This information supports the analyses of serosurveys to detect immunity gaps that require targeted intervention strategies
Low Q^2 Jet Production at HERA and Virtual Photon Structure
The transition between photoproduction and deep-inelastic scattering is
investigated in jet production at the HERA ep collider, using data collected by
the H1 experiment. Measurements of the differential inclusive jet
cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the
transverse energy and the pseudorapidity of the jets in the virtual
photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3
< y < 0.6. The interpretation of the results in terms of the structure of the
virtual photon is discussed. The data are best described by QCD calculations
which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure
Hadron Production in Diffractive Deep-Inelastic Scattering
Characteristics of hadron production in diffractive deep-inelastic
positron-proton scattering are studied using data collected in 1994 by the H1
experiment at HERA. The following distributions are measured in the
centre-of-mass frame of the photon dissociation system: the hadronic energy
flow, the Feynman-x (x_F) variable for charged particles, the squared
transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a
function of x_F. These distributions are compared with results in the gamma^* p
centre-of-mass frame from inclusive deep-inelastic scattering in the
fixed-target experiment EMC, and also with the predictions of several Monte
Carlo calculations. The data are consistent with a picture in which the
partonic structure of the diffractive exchange is dominated at low Q^2 by hard
gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.
Measurement of Leading Proton and Neutron Production in Deep Inelastic Scattering at HERA
Deep--inelastic scattering events with a leading baryon have been detected by
the H1 experiment at HERA using a forward proton spectrometer and a forward
neutron calorimeter. Semi--inclusive cross sections have been measured in the
kinematic region 2 <= Q^2 <= 50 GeV^2, 6.10^-5 <= x <= 6.10^-3 and baryon p_T
<= MeV, for events with a final state proton with energy 580 <= E' <= 740 GeV,
or a neutron with energy E' >= 160 GeV. The measurements are used to test
production models and factorization hypotheses. A Regge model of leading baryon
production which consists of pion, pomeron and secondary reggeon exchanges
gives an acceptable description of both semi-inclusive cross sections in the
region 0.7 <= E'/E_p <= 0.9, where E_p is the proton beam energy. The leading
neutron data are used to estimate for the first time the structure function of
the pion at small Bjorken--x.Comment: 30 pages, 9 figures, 2 tables, submitted to Eur. Phys.
Measurement of D* Meson Cross Sections at HERA and Determination of the Gluon Density in the Proton using NLO QCD
With the H1 detector at the ep collider HERA, D* meson production cross
sections have been measured in deep inelastic scattering with four-momentum
transfers Q^2>2 GeV2 and in photoproduction at energies around W(gamma p)~ 88
GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe
the differential cross sections within theoretical and experimental
uncertainties. Using these calculations, the NLO gluon momentum distribution in
the proton, x_g g(x_g), has been extracted in the momentum fraction range
7.5x10^{-4}< x_g <4x10^{-2} at average scales mu^2 =25 to 50 GeV2. The gluon
momentum fraction x_g has been obtained from the measured kinematics of the
scattered electron and the D* meson in the final state. The results compare
well with the gluon distribution obtained from the analysis of scaling
violations of the proton structure function F_2.Comment: 27 pages, 9 figures, 2 tables, submitted to Nucl. Phys.
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