13,186 research outputs found
Report No. 3: Assessment of Possible Migration Pressure and its Labour Market Impact Following EU Enlargement to Central and Eastern Europe
Study for the Department for Education and Employment of the United Kingdom, Bonn 1999 (117 pages).
On the recombination in high-order harmonic generation in molecules
We show that the dependence of high-order harmonic generation (HHG) on the
molecular orientation can be understood within a theoretical treatment that
does not involve the strong field of the laser. The results for H_2 show
excellent agreement with time-dependent strong field calculations for model
molecules, and this motivates a prediction for the orientation dependence of
HHG from the N_2 3s_g valence orbital. For both molecules, we find that the
polarization of recombination photons is influenced by the molecular
orientation. The variations are particularly pronounced for the N_2 valence
orbital, which can be explained by the presence of atomic p-orbitals.Comment: 6 pages 7 figure
Conversion efficiency and luminosity for gamma-proton colliders based on the LHC-CLIC or LHC-ILC QCD Explorer scheme
Gamma-proton collisions allow unprecedented investigations of the low x and
high regions in quantum chromodynamics. In this paper, we investigate
the luminosity for "ILC"LHC ( TeV) and
"CLIC"LHC ( TeV) based colliders. Also
we determine the laser properties required for high conversion efficiency.Comment: 16, 6 figure
Beam-beam studies for the High-Energy LHC
LHC upgrades are being considered both towards higher luminosity (HL-LHC) and
towards higher energy (HE-LHC). In this paper we report initial studies of the
beam-beam effects in the HE-LHC [1]. The HE-LHC aims at beam energies of 16.5
TeV, where the transverse emittance decreases due to synchrotron radiation with
a 2-hour damping time. As a result of this emittance, shrinkage the beam-beam
parameter increases with time, during a physics store. The beam-beam limit in
the HE-LHC is explored using computer simulations.Comment: 6 pages, contribution to the EuCARD-AccNet-EuroLumi Workshop: The
High-Energy Large Hadron Collider, Malta, 14 -- 16 Oct 201
A cell free system to study synthesis and transport of cytoplasmically translated mitochondiral proteins
Ăśberstundenarbeit und Ăśberstundenkompensation in Deutschland
Im Rahmen der Diskussion zur Lösung des deutschen Beschäftigungsproblems wird als potentieller Lösungsweg die Umverteilung des bestehenden Bestandes an Arbeit gefordert. Erst kürzlich wurde wieder die Verringerung von Überstunden durch die Bundesanstalt für Arbeit und im Rahmen der Gespräche zum „Bündnis für Arbeit" thematisiert. Kann eine derartige Politik zu einer signifikanten Verringerung der Arbeitslosigkeit führen? Oder gibt es auch Mechanismen, die das Gegenteil befürchten lassen? --
Provenance for SPARQL queries
Determining trust of data available in the Semantic Web is fundamental for
applications and users, in particular for linked open data obtained from SPARQL
endpoints. There exist several proposals in the literature to annotate SPARQL
query results with values from abstract models, adapting the seminal works on
provenance for annotated relational databases. We provide an approach capable
of providing provenance information for a large and significant fragment of
SPARQL 1.1, including for the first time the major non-monotonic constructs
under multiset semantics. The approach is based on the translation of SPARQL
into relational queries over annotated relations with values of the most
general m-semiring, and in this way also refuting a claim in the literature
that the OPTIONAL construct of SPARQL cannot be captured appropriately with the
known abstract models.Comment: 22 pages, extended version of the ISWC 2012 paper including proof
Numerical study of the photoelectron cloud in KEKB Low Energy Ring with a three-dimensional particle in cell method
A three-dimensional particle in cell simulation code has been developed to study the photoelectron cloud instabilities in KEKB LER. In this report, the program is described in detail. In particular, typical simulation results are presented for the photoelectron motion in various kinds of magnetic fields. The simulation shows that a solenoid is very effective in confining the photoelectrons to the vicinity of the vacuum chamber wall and in creating a region free of photoelectrons at the vacuum pipe center. The more uniform the solenoid field is, the more effectively does it suppress the electron-cloud buildup. Multipacting can occur both in a drift region and in a dipole magnet, and the heat load deposited on the chamber wall due to the lost electrons is important in these two cases. Electron trapping by the beam field as well as by various magnetic fields is an important phenomenon, especially inside quadrupole and sextupole magnets. Our numerical results qualitatively agree with the experimental studies
The FCC-ee Interaction Region Magnet Design
The design of the region close to the interaction point of the FCC-ee
experiments is especially challenging. The beams collide at an angle (+-15
mrad) in the high-field region of the detector solenoid. Moreover, the very low
vertical beta_y* of the machine necessitates that the final focusing
quadrupoles have a distance from the IP (L*) of around 2 m and therefore are
inside the main detector solenoid. The beams should be screened from the effect
of the detector magnetic field, and the emittance blow-up due to vertical
dispersion in the interaction region should be minimized, while leaving enough
space for detector components. Crosstalk between the two final focus
quadrupoles, only about 6 cm apart at the tip, should also be minimized.Comment: Poster presented at IPAC16, May 8-13, Busan, Kore
Catalytic hydrogenation of α,β-unsaturated carboxylic acid derivatives using copper(i)/N-heterocyclic carbene complexes
A simple and air-stable copper(I)/N-heterocyclic carbene complex enables the catalytic hydrogenation of enoates and enamides, hitherto unreactive substrates employing homogeneous copper catalysis and H2 as a terminal reducing agent. This atom economic transformation replaces commonly employed hydrosilanes and can also be carried out in an asymmetric fashion.TU Berlin, Open-Access-Mittel - 201
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