2,275 research outputs found
Impact of Neutron Decay Experiments on non-Standard Model Physics
This paper gives a brief overview of the present and expected future limits
on physics beyond the Standard Model (SM) from neutron beta decay, which is
described by two parameters only within the SM. Since more than two observables
are accessible, the problem is over-determined. Thus, precise measurements of
correlations in neutron decay can be used to study the SM as well to search for
evidence of possible extensions to it. Of particular interest in this context
are the search for right-handed currents or for scalar and tensor interactions.
Precision measurements of neutron decay observables address important open
questions of particle physics and cosmology, and are generally complementary to
direct searches for new physics beyond the SM in high-energy physics. Free
neutron decay is therefore a very active field, with a number of new
measurements underway worldwide. We present the impact of recent developments.Comment: 13 pages, 6 figures; Proceedings of the 5th International BEYOND 2010
Conference, Cape Town, South Africa (2010), World Scientific, accepted for
publication; Corrected typo
Xenogeneic, extracorporeal liver perfusion in primates improves the ratio of branched-chain amino acids to aromatic amino acids (Fischer's ratio)
In fulminant hepatic failure (FHF), the development of hepatic encephalopathy is associated with grossly abnormal concentrations of plasma amino acids (PAA). Normalization of the ratio of branched-chain amino acids to aromatic amino acids (Fischer's ratio) correlates with clinical improvement. This study evaluated changes in PAA metabolism during 4 h of isolated, normothermic extracorporeal liver perfusion using a newly designed system containing human blood and a rhesus monkey liver. Bile and urea production were within the physiological range. Release of the transaminases AST, ALT and LDH were minimal. The ratio of branched (valine, leucine, isoleucine) to aromatic (tyrosine, phenylalanine) amino acids increased significantly. These results indicate that a xenogeneic extracorporeal liver perfusion system is capable of significantly increasing Fischer's ratio and may play a role in treating and bridging patients in FHF in the future
Ultrasensitive 3He magnetometer for measurements of high magnetic fields
We describe a 3He magnetometer capable to measure high magnetic fields (B >
0.1 Tesla) with a relative accuracy of better than 10^-12. Our approach is
based on the measurement of the free induction decay of gaseous, nuclear spin
polarized 3He following a resonant radio frequency pulse excitation. The
measurement sensitivity can be attributed to the long coherent spin precession
time T2* being of order minutes which is achieved for spherical sample cells in
the regime of motional narrowing where the disturbing influence of field
inhomogeneities is strongly suppressed. The 3He gas is spin polarized in-situ
using a new, non-standard variant of the metastability exchange optical
pumping. We show that miniaturization helps to increase T2* further and that
the measurement sensitivity is not significantly affected by temporal field
fluctuations of order 10^-4.Comment: 27 pages, 7 figure
Strain and family effects on resistance of "Leghorn" hens against different dissae
International audienc
Test of Lorentz Symmetry by using a 3He/129Xe Co-Magnetometer
To test Lorentz symmetry we used a 3He/129Xe co-magnetometer. We will give a
short summary of our experimental setup and the results of our latest
measurements. We obtained preliminary results for the equatorial component of
the background field interacting with the spin of the bound neutron: b_n < 3.72
x 10^(-32) GeV (95 C.L.).Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28 - July 2, 201
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