3,754 research outputs found
Geloof in kloppend bewijs
Rede,
In verkorte vorm uitgesproken
ter gelegenheid van het aanvaarden
van het ambt van bijzonder hoogleraar
Klinische epidemiologie van hart- en vaatziekten
aan het Erasmus MC, faculteit van de
Erasmus Universiteit Rotterdam
op 20 maart 2009.
De leidende gedachte binnen het vakgebied Klinische epidemiologie is dat
medisch handelen gebaseerd dient te zijn op het best beschikbare bewijs van
zijn werkzaamheid en doeltreffendheid. Dat bewijs is niet gegrond op de persoonlijke
ervaring van patiënten, noch op de klinische expertise van individuele artsen, hoe
waardevol deze elementen ook zijn. Maar het bewijs voor de effectiviteit van het
klinisch handelen is bij voorkeur afkomstig van wetenschappelijk onderzoek onder
groepen patiënten, waarin theoretische concepten worden getoetst, en waarbij
gezocht wordt naar relaties tussen het optreden en het beloop van ziekten enerzijds,
en verklarende factoren of determinanten daarvan anderzijds.|1 Deze determinanten
kunnen zowel oorzakelijke als niet-oorzakelijke factoren zijn. Vanzelfsprekend dient
onderzoek naar determinant-uitkomst relaties te worden opgezet en uitgevoerd in
overeenstemming met kwalitatief hoogstaande standaarden
Correlations and the relativistic structure of the nucleon self-energy
A key point of Dirac Brueckner Hartree Fock calculations for nuclear matter
is to decompose the self energy of the nucleons into Lorentz scalar and vector
components. A new method is introduced for this decomposition. It is based on
the dependence of the single-particle energy on the small component in the
Dirac spinors used to calculate the matrix elements of the underlying NN
interaction. The resulting Dirac components of the self-energy depend on the
momentum of the nucleons. At densities around and below the nuclear matter
saturation density this momentum dependence is dominated by the non-locality of
the Brueckner G matrix. At higher densities these correlation effects are
suppressed and the momentum dependence due to the Fock exchange terms is
getting more important. Differences between symmetric nuclear matter and
neutron matter are discussed. Various versions of the Bonn potential are
considered.Comment: 18 pages LaTeX, including 6 figure
Relativistic Structure of the Nucleon Self-Energy in Asymmetric Nuclei
The Dirac structure of the nucleon self-energy in asymmetric nuclear matter
cannot reliably be deduced from the momentum dependence of the single-particle
energies. It is demonstrated that such attempts yield an isospin dependence
with even a wrong sign. Relativistic studies of finite nuclei have been based
on such studies of asymmetric nuclear matter. The effects of these isospin
components on the results for finite nuclei are investigated.Comment: 9 pages, Latex 4 figures include
Case study: Ticagrelor in plato and prasugrel in triton-timi 38 and trilogy-acs trials in patients with acute coronary syndromes
Copyrigh
Seasonal variation in the interactions between piscivorous fish, planktivorous fish and zooplankton in a shallow eutrophic lake
An individual approach to thrombolytic therapy in patients with evolving myocardial infarction
Averaging kernels for DOAS total-column satellite retrievals
International audienceThe Differential Optical Absorption Spectroscopy (DOAS) method is used extensively to retrieve total column amounts of trace gases based on UV-visible measurements of satellite spectrometers, such as ERS-2 GOME. In practice the sensitivity of the instrument to the tracer density is strongly height dependent, especially in the troposphere. The resulting tracer profile dependence may introduce large systematic errors in the retrieved columns that are difficult to quantify without proper additional information, as provided by the averaging kernel (AK). In this paper we discuss the DOAS retrieval method in the context of the general retrieval theory as developed by Rodgers. An expression is derived for the DOAS AK for optically thin absorbers. It is shown that the comparison with 3D chemistry-transport models and independent profile measurements, based on averaging kernels, is no longer influenced by errors resulting from a priori profile assumptions. The availability of averaging kernel information as part of the total column retrieval product is important for the interpretation of the observations, and for applications like chemical data assimilation and detailed satellite validation studies
Paradoxes of studentification: social mix versus gentrification in a disadvantaged neighborhood in Amsterdam East
Study of relativistic bound state wave functions in quasielastic (e,e'p) reactions
The unpolarized response functions of the quasielastic reaction are calculated for three different types of relativistic
bound state wave functions. The wave functions are obtained from relativistic
Hartree, relativistic Hartree-Fock and density dependent relativistic Hartree
calculations that reproduce the experimental charge radius of O. The
sensitivity of the unpolarized response functions to the single particle
structure of the different models is investigated in the relativistic plane
wave impulse approximation. Redistributions of the momentum dependence in the
longitudinal and transverse response function can be related to the binding
energy of the single particle states. The interference responses and
reveal a strong sensitivity to the small component of the relativistic
bound state wave function.Comment: 18 pages REVTEX, 5 figures include
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