5,716 research outputs found
Ernst Herbst Prüftechnik e.K. - Plant protection equipment, test engineering, agricultural technology
contribution to exhibitio
Sprayer-Testing - Electronic analysis of the test reports
contribution to optional evening activities - presentation
Economic Comparison of the Farm, Nutrition, and Bioenergy Act (H.R. 2419) to Fairness in Farm and Food Policy Amendment to H.R. 2419
The House Agriculture Committee unanimously passed their farm bill, “Farm, Nutrition and Bioenergy Act of 2007” (H.R. 2419). An amendment, “Fairness in Farm and Food Policy,” H.R. 2419 was announced by Ron Kind (D-WI). The purpose of this Briefing Report is to compare the likely economic impacts of H.R. 2419 and the FFFP Amendment on representative crop, dairy, and cattle farms.Agricultural and Food Policy,
On the phase structure and thermodynamics of QCD
We discuss the phase structure and thermodynamics of QCD by means of
dynamical chiral effective models. Quark and meson fluctuations are included
via the functional renormalization group. We study the influence of confinement
in addition to the impact of fluctuations by comparing the results of the
chiral models to their Polyakov-loop extended versions. Furthermore, we discuss
the mass sensitivity of the phase structure and thermodynamics and find
interesting modifications close to the chiral limit.Comment: 13 pages, 11 figures; Appendix added; published versio
D-brane Categories for Orientifolds -- The Landau-Ginzburg Case
We construct and classify categories of D-branes in orientifolds based on
Landau-Ginzburg models and their orbifolds. Consistency of the worldsheet
parity action on the matrix factorizations plays the key role. This provides
all the requisite data for an orientifold construction after embedding in
string theory. One of our main results is a computation of topological field
theory correlators on unoriented worldsheets, generalizing the formulas of Vafa
and Kapustin-Li for oriented worldsheets, as well as the extension of these
results to orbifolds. We also find a doubling of Knoerrer periodicity in the
orientifold context.Comment: 45 pages, 6 figure
Boundary states, matrix factorisations and correlation functions for the E-models
The open string spectra of the B-type D-branes of the N=2 E-models are
calculated. Using these results we match the boundary states to the matrix
factorisations of the corresponding Landau-Ginzburg models. The identification
allows us to calculate specific terms in the effective brane superpotential of
E_6 using conformal field theory methods, thereby enabling us to test results
recently obtained in this context.Comment: 20 pages, no figure
Exploring the Phase Structure and Thermodynamics of QCD
We put forward a Polyakov-loop extended quark meson model, where matter as
well as glue fluctuations are taken into account, cf. [1]. The latter are
included via a Polyakov-loop potential. Usually such a glue potential is based
on Yang-Mills lattice data only. We show that a parametrisation of unquenching
effects as proposed in [2], together with the inclusion of fluctuations via the
functional renormalisation group [3,4], accounts for the relevant dynamics.
This is demonstrated by a comparison of order parameters and thermodynamic
observables to recent lattice results at vanishing chemical potential, where we
find very good agreement.Comment: 11 pages, 2 figures, contribution to "QCD-TNT-III: From quarks and
gluons to hadronic matter: A bridge too far?", ECT*, Trento (Italy),
September 2-6, 201
Results of the ROTOR-program. I. The long-term photometric variability of classical T Tauri stars
We present a unique, homogeneous database of photometric measurements for
Classical T Tauri stars extending up to 20 years. The database contains more
than 21,000 UBVR observations of 72 CTTs. All the data were collected within
the framework of the ROTOR-program at Mount Maidanak Observatory (Uzbekistan)
and together they constitute the longest homogeneous, accurate record of TTS
variability ever assembled. We characterize the long term photometric
variations of 49 CTTs with sufficient data to allow a robust statistical
analysis and propose an empirical classification scheme. Several patterns of
long term photometric variability are identified. The most common pattern,
exhibited by a group of 15 stars which includes T Tau itself, consists of low
level variability (Delta(V)<=0.4mag) with no significant changes occurring from
season to season over many years. A related subgroup of 22 stars exhibits a
similar stable long term variability pattern, though with larger amplitudes (up
to Delta(V)~1.6 mag). Besides these representative groups, we identify three
smaller groups of 3-5 stars each which have distinctive photometric properties.
The long term variability of most CTTs is fairly stable and merely reflects
shorter term variability due to cold and hot surface spots. Only a small
fraction of CTTs undergo significant brightness changes on the long term
(months, years), which probably arise from slowly varying circumstellar
extinction.Comment: 16 pages, 11 figures. Astron. Astrophys., in pres
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