6,857 research outputs found
Experiences in biochemical diagnosis of suicide by analyzing Serotonin in cerebrospinal fluid
The Galactic Center as a point source of neutrons at EeV energies
The central region of our Galaxy is a very peculiar environment, containing
magnetic fields in excess of 100 mG and gas densities reaching ~ 10^4cm^-3.
This region was observed as a strong source of GeV and TeVs gammas, what
suggests that a mechanism of proton-neutron conversion could be taking place
therein. We propose that the Galactic Center must also be a source of EeV
neutrons due to the conversion of ultra high energy cosmic ray protons into
neutrons via p-p interactions inside this region. This scenario should be
falsifiable by the Pierre Auger Observatory after a few years of full exposure
Core structure of EAS in 10(15) to 10(17) eV
With the use of Akeno calorimeter, the attenuation of particles in concrete is analyzed as the function of the shower size of 10 to the 5th power to 10 to the 7th power. The attenuation length does not depend much on the shower size but depends a little on the shower age. The average value is approx. 150 g/sq cm for s = 0.5 to 0.85 and approx. 40 g/sq cm for s = 0.85 to 1.15. These values and their fluctuations are consistent with the equi-intensity curves of extensive air showers (EAS)
Measurement of energy muons in EAS at energy region larger thean 10(17) eV
A measurement of low energy muons in extensive air showers (EAS) (threshold energies are 0.25, 0.5, 0.75 and 1.38 GeV) was carried out. The density under the concrete shielding equivalent to 0.25 GeV at core distance less than 500 m and 0.5 GeV less than 150 m suffers contamination of electromagnetic components. Therefore the thickness of concrete shielding for muon detectors for the giant air shower array is determined to be 0.5 GeV equivalence. Effects of photoproduced muons are found to be negligible in the examined ranges of shower sizes and core distances. The fluctuation of the muon density in 90 sq m is at most 25% between 200 m and 600 m from the core around 10 to the 17th power eV
EAS development curve at energy of 10(16) - 10(18) eV measured by optical Cerenkov light
The data of optical Cerenkov light from extensive air shower observed at the core distance more than 1 Km at Akeno are reexamined. Applying the new simulated results, the shower development curves for the individual events were constructed. For the showers of 10 to 17th power eV the average depth at the shower maximum is determined to be 660 + or - 40 gcm/2. The shower curve of average development is found to be well described by a Gaisser-Hillas shower development function with above shower maximum depth
MACiE: a database of enzyme reaction mechanisms.
SUMMARY: MACiE (mechanism, annotation and classification in enzymes) is a publicly available web-based database, held in CMLReact (an XML application), that aims to help our understanding of the evolution of enzyme catalytic mechanisms and also to create a classification system which reflects the actual chemical mechanism (catalytic steps) of an enzyme reaction, not only the overall reaction. AVAILABILITY: http://www-mitchell.ch.cam.ac.uk/macie/.EPSRC (G.L.H. and J.B.O.M.), the BBSRC (G.J.B. and J.M.T.—CASE studentship in association with Roche Products Ltd; N.M.O.B. and J.B.O.M.—grant BB/C51320X/1), the Chilean Government’s Ministerio de Planificacio´n y Cooperacio´n and
Cambridge Overseas Trust (D.E.A.) for funding and Unilever for supporting the Centre for Molecular Science Informatics.application note restricted to 2 printed pages web site: http://www-mitchell.ch.cam.ac.uk/macie
Effect of multiple reusing of simulated air showers in detector simulations
The study of high energy cosmic rays requires detailed Monte Carlo
simulations of both, extensive air showers and the detectors involved in their
detection. In particular, the energy calibration of several experiments is
obtained from simulations. Also, in composition studies simulations play a
fundamental role because the primary mass is determined by comparing
experimental with simulated data. At the highest energies the detailed
simulation of air showers is very costly in processing time and disk space due
to the large number of secondary particles generated in interactions with the
atmosphere. Therefore, in order to increase the statistics, it is quite common
to recycle single showers many times to simulate the detector response. As a
result, the events of the Monte Carlo samples generated in this way are not
fully independent. In this work we study the artificial effects introduced by
the multiple use of single air showers for the detector simulations. In
particular, we study in detail the effects introduced by the repetitions in the
kernel density estimators which are frequently used in composition studies.Comment: 15 pages and 4 figure
Analytical expressions for the charge-charge local-field factor and the exchange-correlation kernel of a two-dimensional electron gas
We present an analytical expression for the static many-body local field
factor of a homogeneous two-dimensional electron gas, which
reproduces Diffusion Monte Carlo data and embodies the exact asymptotic
behaviors at both small and large wave number . This allows us to also
provide a closed-form expression for the exchange and correlation kernel
, which represents a key input for density functional studies of
inhomogeneous systems.Comment: 5 pages, 3 figure
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