462 research outputs found
Overdreven gezondheidsnieuws. Relatie tussen overdrijving in academische persberichten en in nieuwsmedia
Objective: To
determine how often press releases and news articles contain exaggeration and
to locate its origin in the trajectory from research paper to news article.
Design: Retrospective
quantitative content analysis
Method: Sample
used consists of press releases on biomedical research, published by 15 Dutch universities and university medical
centers in 2015 (N=129), and associated news articles (N=185) and peer reviewed
research papers. Quantitative content analysis was performed using Rstudio.
Results: 20% of press releases and 29% of news articles contain
exaggeration of conclusion of causal claim. Explicit health advice was, when
present, exaggerated in 7% of press releases and 10% of news articles. When the
press releases contained an exaggeration of conclusion of causal claim, 92% of
associated news articles was exaggerated as well (N=34). When the conclusion or
causal claim in press releases was not exaggerated, 6% of associated news
articles contained exaggeration (N=6). The relative chance of exaggeration in
news is 16.1 when the associated press release is exaggerated. Additionally we
found that exaggerated press releases have a higher number of associated news articles.
The relative chance of news uptake for exaggerated press releases compared with
non-exaggerated press releases is 1.45 (1,02-2,04).
Conclusion: Exaggeration
of health related news is strongly associated with exaggeration in the
associated press release and occurs in more than 1 in 5 articles. Monitoring
and, if necessary, improving the accuracy of academic press releases are likely
to be important measures to improve the quality of health news. Science Communication and Societ
Monte-Carlo sampling of energy-constrained quantum superpositions in high-dimensional Hilbert spaces
Recent studies into the properties of quantum statistical ensembles in
high-dimensional Hilbert spaces have encountered difficulties associated with
the Monte-Carlo sampling of quantum superpositions constrained by the energy
expectation value. A straightforward Monte-Carlo routine would enclose the
energy constrained manifold within a larger manifold, which is easy to sample,
for example, a hypercube. The efficiency of such a sampling routine decreases
exponentially with the increase of the dimension of the Hilbert space, because
the volume of the enclosing manifold becomes exponentially larger than the
volume of the manifold of interest. The present paper explores the ways to
optimise the above routine by varying the shapes of the manifolds enclosing the
energy-constrained manifold. The resulting improvement in the sampling
efficiency is about a factor of five for a 14-dimensional Hilbert space. The
advantage of the above algorithm is that it does not compromise on the rigorous
statistical nature of the sampling outcome and hence can be used to test other
more sophisticated Monte-Carlo routines. The present attempts to optimise the
enclosing manifolds also bring insights into the geometrical properties of the
energy constrained manifold itself.Comment: 9 pages, 7 figures, accepted for publication in European Physical
Journal
RNA expression of breast cancer resistance protein, lung resistance-related protein, multidrug resistance-associated proteins 1 and 2, and multidrug resistance gene 1 in breast cancer: correlation with chemotherapeutic response
PURPOSE: The aim of this study was to investigate whether expression of
particular drug resistance genes in primary operable breast cancer
correlates with response to first-line chemotherapy in advanced disease.
EXPERIMENTAL DESIGN: We determined mRNA levels of BCRP, LRP, MRP1, MRP2,
and MDR1 in 59 primary breast tumor specimens of patients who
Progestogenic effects of tibolone on human endometrial cancer cells
Tibolone, a synthetic steroid acting in a tissue-specific manner and used
in hormone replacement therapy, is converted into three active
metabolites: a Delta(4) isomer (exerting progestogenic and androgenic
effects) and two hydroxy metabolites, 3 alpha-hydroxytibolone (3
alpha-OH-tibolone) and 3beta-OH-tibolone (exerting estrogenic effects). In
the present study an endometrial carcinoma cell line (Ishikawa PRAB-36)
was used to investigate the progestogenic properties of tibolone and its
metabolites. This cell line contains progesterone receptors A and B, but
lacks estrogen and androgen receptors. When tibolone was added to the
cells, complete conversion into the progestogenic/androgenic Delta(4)
isomer was observed within 6 d. Furthermore, when cells were cultured with
tibolone or when the Delta(4) isomer or the established progestagen
medroxyprogesterone acetate was added to the medium, marked inhibition of
growth was observed. Interestingly, 3 beta-OH-tibolone also induces some
inhibition of growth. These growth inhibitions were not observed in
progesterone receptor-negative parental Ishikawa cells, and
progestagen-induced growth inhibition of PRAB-36 cells could readily be
reversed using the antiprogestagen Org-31489. Upon measuring the
expression of two progesterone-regulated genes (fibronectin and
IGF-binding protein-3), tibolone, the Delta(4) isomer and
medroxyprogesterone acetate showed similar gene expression regulation.
These results indicate that tibolone, the Delta(4) metabolite, and to some
extent 3 beta-OH-tibolone exert progestogenic effects. Tibolone and most
likely 3 beta-OH-tibolone are converted into the Delta(4) metabolite
Far-infrared vibrational properties of high-pressure-high-temperature C60 polymers and the C60 dimer
We report high-resolution far-infrared transmission measurements of the 2 + 2 cycloaddition C-60 dimer and two-dimensional rhombohedral and one-dimensional orthorhombic high-pressure high-temperature C60 polymers. In the spectral region investigated(20-650 cm(-1)), we see no low-energy interball modes, but symmetry breaking of the linked C-60 balls is evident in the complex spectrum of intramolecular modes. Experimental features suggest large splittings or frequency shifts of some IhC60-derived modes that are activated by symmetry reduction, implying that the balls are strongly distorted in these structures. We have calculated the vibrations of all three systems by first-principles quantum molecular dynamics and use them to assign the predominant IhC60 symmetries of observed modes. Pur calculations show unprecedentedly large downshifts of T-1u(2)-derived modes and extremely large splittings of other modes, both of which are consistent with the experimental spectra. For the rhombohedral and orthorhombic polymers, the T-1u(2)-derived mode that is polarized along the bonding direction is calculated to downshift below any T-1u(1)-derived modes. We also identify a previously unassigned feature near 610 cm(-1) in all three systems as a widely split or shifted mode derived from various silent IhC60 vibrations, confirming a strong perturbation model for these linked fullerene structures
Angular momenta creation in relativistic electron-positron plasma
Creation of angular momentum in a relativistic electron-positron plasma is
explored. It is shown that a chain of angular momentum carrying vortices is a
robust asymptotic state sustained by the generalized nonlinear Schrodinger
equation characteristic to the system. The results may suggest a possible
electromagnetic origin of angular momenta when it is applied to the MeV epoch
of the early Universe.Comment: 20 pages, 6 figure
Water Management Solution of Reservoir Storage Function Under Condition of Measurement Uncertainties in Hydrological Input Data
AbstractThe paper describes a possible procedure of the rate uncertainty implementation to the continuous water stage measurement and uncertainties of state - discharge rating curve point positions, which the stage -discharge rating curves were fitted into the uncertainties of the real discharge series members. Then the members of discharge series under uncertainty impact were tested on the calculated values of the reservoir storage volume. The next step was the implementation of the uncertainties of the real discharge series members on the generation of the artificial discharge series of mean monthly discharge using the AR and ARMA generators and the determination of their impact on the calculated values of the reservoir storage volume
Measurement of the W+W-gamma Cross Section and Direct Limits on Anomalous Quartic Gauge Boson Couplings at LEP
The process e+e- -> W+W-gamma is analysed using the data collected with the
L3 detector at LEP at a centre-of-mass energy of 188.6GeV, corresponding to an
integrated luminosity of 176.8pb^-1. Based on a sample of 42 selected W+W-
candidates containing an isolated hard photon, the W+W-gamma cross section,
defined within phase-space cuts, is measured to be: sigma_WWgamma = 290 +/- 80
+/- 16 fb, consistent with the Standard Model expectation. Including the
process e+e- -> nu nu gamma gamma, limits are derived on anomalous
contributions to the Standard Model quartic vertices W+W- gamma gamma and W+W-Z
gamma at 95% CL: -0.043 GeV^-2 < a_0/Lambda^2 < 0.043 GeV^-2 0.08 GeV^-2 <
a_c/Lambda^2 < 0.13 GeV^-2 0.41 GeV^-2 < a_n/Lambda^2 < 0.37 GeV^-2
Production of Single W Bosons at \sqrt{s}=189 GeV and Measurement of WWgamma Gauge Couplings
Single W boson production in electron-positron collisions is studied with the
L3 detector at LEP. The data sample collected at a centre-of-mass energy of
\sqrt{s} = 188.7GeV corresponds to an integrated luminosity of 176.4pb^-1.
Events with a single energetic lepton or two acoplanar hadronic jets are
selected. Within phase-space cuts, the total cross-section is measured to be
0.53 +/- 0.12 +/- 0.03 pb, consistent with the Standard Model expectation.
Including our single W boson results obtained at lower \sqrt{s}, the WWgamma
gauge couplings kappa_gamma and lambda_gamma are determined to be kappa_gamma =
0.93 +/- 0.16 +/- 0.09 and lambda_gamma = -0.31 +0.68 -0.19 +/- 0.13
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