5,160 research outputs found
Bremsstrahlung from relativistic heavy ions in a fixed target experiment at the LHC
We calculate the emission of bremsstrahlung from lead and argon ions in A
Fixed Target ExpeRiment (AFTER) that uses the LHC beams. With nuclear charges
of equal and respectively, these ions are accelerated to
energies of TeV. The bremsstrahlung peaks around
GeV and the spectrum exposes the nuclear structure of the incoming ion. The
peak structure is significantly different from the flat power spectrum
pertaining to a point charge. Photons are predominantly emitted within an angle
of to the direction of ion propagation. Our calculations are based
on the Weizs\"{a}cker-Williams method of virtual quanta with application of
existing experimental data on photonuclear interactions.Comment: 9 pages, 3 figures. Submitted to Advances in High Energy Physic
Biological activity of glucosinolate derived compounds isolated from seed meal of Brassica crops and evaluated as plant and food protection agents
Glucosinolates are amino acid derived allelochemicals characteristic of plants of the order Capparales. These compounds are present in seeds of agriculturally common Brassica crops in varying quantities depending on the species (ref). The use of the remaining seed cake after oil extraction has traditionally been limited by the concentration of these compounds. However, the extraction of glucosinolates from seed meal is nowadays possible and it further contributes to an increased quality of the seed meal for feed (Sørensen et al., this conference). Glucosinolates are hydrolysed by endogenous enzymes (myrosinases; EC 3.2.1.147) and a number of compounds are produced depending on the parent glucosinolate and the environmental conditions.1 Among these compounds, oxazolidine-2-thiones are known for their antinutritional effects on monogastric animals, whereas isothiocyanates are fungicidal, nematocidal and herbicidal.2,3 The possibility for using glucosinolates as precursors for environmental friendly biocides therefore exists, which could contribute to increase the value of the Brassica seed meal
Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice
We demonstrate preparation and detection of an atom number distribution in a
one-dimensional atomic lattice with the variance dB below the Poissonian
noise level. A mesoscopic ensemble containing a few thousand atoms is trapped
in the evanescent field of a nanofiber. The atom number is measured through
dual-color homodyne interferometry with a pW-power shot noise limited probe.
Strong coupling of the evanescent probe guided by the nanofiber allows for a
real-time measurement with a precision of atoms on an ensemble of some
atoms in a one-dimensional trap. The method is very well suited for
generating collective atomic entangled or spin-squeezed states via a quantum
non-demolition measurement as well as for tomography of exotic atomic states in
a one-dimensional lattice
The Ground State Energy of Heavy Atoms According to Brown and Ravenhall: Absence of Relativistic Effects in Leading Order
It is shown that the ground state energy of heavy atoms is, to leading order,
given by the non-relativistic Thomas-Fermi energy. The proof is based on the
relativistic Hamiltonian of Brown and Ravenhall which is derived from quantum
electrodynamics yielding energy levels correctly up to order Ry
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