425 research outputs found
'Piglet snatching' in de praktijk
Piglet snatching is een goedkope methode voor het vrijmaken van een varkenspopulatie op een bedrijf van een aantal schadelijke ziekteverwekkers
From soft harmonic phonons to fast relaxational dynamics in CHNHPbBr
The lead-halide perovskites, including CHNHPbBr, are
components in cost effective, highly efficient photovoltaics, where the
interactions of the molecular cations with the inorganic framework are
suggested to influence the electronic and ferroelectric properties.
CHNHPbBr undergoes a series of structural transitions
associated with orientational order of the CHNH (MA) molecular
cation and tilting of the PbBr host framework. We apply high-resolution
neutron scattering to study the soft harmonic phonons associated with these
transitions, and find a strong coupling between the PbBr framework and
the quasistatic CHNH dynamics at low energy transfers. At higher
energy transfers, we observe a PbBr octahedra soft mode driving a
transition at 150 K from bound molecular excitations at low temperatures to
relatively fast relaxational excitations that extend up to 50-100 meV.
We suggest that these temporally overdamped dynamics enables possible indirect
band gap processes in these materials that are related to the enhanced
photovoltaic properties.Comment: (main text - 5 pages, 4 figures; supplementary information - 3 pages,
3 figures
Monitoring Varkensproefbedrijf Lelystad
Varkensproefbedrijf de Waiboerhoeve in Lelystad gaat de komende jaren de hoge gezondheidstatus van de varkenspopulatie screnen met behulp van verschillende testmethoden. Dit om vast te kunnen stellen in welke mate deze status behouden kan worden met een stringent maar praktijkgericht hygiëneprotoco
Eerste varkens gearriveerd in Lelystad!
Aangezien het proefbedrijf is gebouwd in een varkensarm gebied is gekozen voor varkens afkomstig van een SPF-populatie
Enhanced thermal production of hard dileptons by processes
In the framework of the Hard Thermal Loop effective theory, we calculate the
two-loop contributions to hard lepton pair production in a quark-gluon plasma.
We show that the result is free of any infrared and collinear singularity. We
also recover the known fact that perturbation theory leads to integrable
singularities at the location of the threshold for . It
appears that the process calculated here significantly enhances the rate of low
mass hard dileptons.Comment: 32 latex pages, 14 postscript figure
Comments on two papers by Kapusta and Wong
We critically examine recently published results on the thermal production of
massive vector bosons in a quark-gluon plasma. We claim the production rate is
a collinear safe observable.Comment: 6 pages LATEX documen
Via (diergezondheids-)management naar minimalisering van antibioticagebruik : resultaten van een experimentele fase met biologische varkensbedrijven
Experiences of organic pig farms with minimizing antibiotic use through strengthening the animal health management
An operator representation for Matsubara sums
In the context of the imaginary-time formalism for a scalar thermal field
theory, it is shown that the result of performing the sums over Matsubara
frequencies associated with loop Feynman diagrams can be written, for some
classes of diagrams, in terms of the action of a simple linear operator on the
corresponding energy integrals of the Euclidean theory at T=0. In its simplest
form the referred operator depends only on the number of internal propagators
of the graph.
More precisely, it is shown explicitly that this \emph{thermal operator
representation} holds for two generic classes of diagrams, namely, the
two-vertex diagram with an arbitrary number of internal propagators, and the
one-loop diagram with an arbitrary number of vertices.
The validity of the thermal operator representation for diagrams of more
complicated topologies remains an open problem. Its correctness is shown to be
equivalent to the correctness of some diagrammatic rules proposed a few years
ago.Comment: 4 figures; references added, minor changes in notation, final version
accepted for publicatio
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