11,071 research outputs found
Staphylococcus food poisoning: recommendations for its prevention and control
Mr. Dewberry, a Fellow of the Society of Health and of the Institute of Public Health and Hygiene, served with The historic Mediterranean Fever Commission in Malta in 1904-05 and may be the last survivor of that celebrated group. In this article he puts forward several recommendations for the prevention and control of staphylococcus food poisoning. Staphylococcus bacterium is commonly found in nature and the organisms are widespread among healthy persons, being present on the skin, in the throat and in the nasal passages. In the majority of the outbreaks occurring in England and Wales due to the enterotoxin, the incriminated vehicle has been a protein foodstuff (meat), which has been cooked the day previous to its being consumed. There appears to be only one effective way of controlling this type of food poisoning and that is to prevent pathogenic staphylococci from producing the enterotoxin in cooked protein foods. In this regard, guidance in treating stored food, including the maximum temperatures at which to keep cold or hot cooked protein foods is provided. In essence, since enterotoxin is odourless, colourless and tasteless, one cannot depend on the appearance, taste or smell of cooked protein food.peer-reviewe
On Combining High and Low Q**2 Information on the Polarized Parton Densities
We draw attention to some problems in the combined use of high-Q^2 deep
inelastic scattering (DIS) data and low-Q^2 hyperon \beta-decay data in the
determination of the polarized parton densities. We explain why factorization
schemes like the JET or AB schemes are the simplest in which to study the
implications of the DIS parton densities for the physics of the low-Q^2 region.Comment: 10 pages, LaTeX, minor corrections made in Section 4, a reference
added, to be published in JHE
Higher Twist Effects in Polarized DIS
The size of higher twist corrections to the spin proton and neutron g1
structure functions and their role in determining the polarized parton
densities in the nucleon is discussed.Comment: 6 pages, 2 figures, to appear in the proceedings of First Workshop on
Quark-Hadron Duality and the Transition to pQCD, Frascati, June 6-8, 200
Polarized Parton Densities in the Nucleon
We present a new NLO QCD analysis of the world data on inclusive polarized
deep inelastic scattering. Comparing to our previous analysis: i) the values of
g_A and a_8=3F-D are updated ii) the MRST'99 instead of the MRST'98
parametrization for the input unpolarized parton densities is used and iii) the
recent SLAC E155 proton data on the spin asymmetry A1 are included in the
analysis. A new set of polarized parton densities is extracted from the data
and the sensitivity of the results to different positivity constraints is
discussed.Comment: 4 pages, 1 figure, LaTeX, typing errors in the numbers for \Delta
\Sigma are corrected, talk presented at the 9th International Workshop on
Deep Inelastic Scattering and QCD (DIS2001), Bologna, Italy, 27 Apr-1 May
200
Acoustic evaluation of the Helmholtz resonator treatment in the NASA Lewis 8- by 6-foot supersonic wind tunnel
The acoustic consequences of sealing the Helmholtz resonators of the NASA Lewis 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT) were experimentally evaluated. This resonator sealing was proposed in order to avoid entrapment of hydrogen during tests of advanced hydrogen-fueled engines. The resonators were designed to absorb energy in the 4- to 20-Hz range; thus, this investigation is primarily concerned with infrasound. Limited internal and external noise measurements were made at tunnel Mach numbers ranging from 0.5 to 2.0. Although the resonators were part of the acoustic treatment installed because of a community noise problem their sealing did not seem to indicate a reoccurrence of the problem would result. Two factors were key to this conclusion: (1) A large bulk treatment muffler downstream of the resonators was able to make up for much of the attenuation originally provided by the resonators, and (2) there was no noise source in the tunnel test section. The previous community noise problem occurred when a large ramjet was tested in an open-loop tunnel configuration. If a propulsion system producing high noise levels at frequencies of less than 10 Hz were tested, the conclusion on community noise would have to be reevaluated
Determination of the fragmentation functions from an NLO QCD analysis of the HERMES data on pion multiplicities
An NLO QCD analysis of the final HERMES data on pion multiplicities is
presented and a new set of pion fragmentation functions is extracted from the
best fit to the data. We have studied the so-called [x,z] and [Q^2,z]
presentations of their data, as given by HERMES, which, in principle, should
simply be two different ways of presenting the experimental data. We have based
our extraction on an excellent fit to the [Q^2,z] presentation of the data. We
also draw attention to what appears to be a problem with the [x,z] presentation
of the HERMES data.Comment: 12 pages, 7 figures; This updated version corresponds to the paper
accepted for publication in Phys. Rev.
New analysis concerning the strange quark polarization puzzle
The fact that analyses of semi-inclusive deep inelastic scattering suggest
that the polarized strange quark density is
positive in the measured region of Bjorken x, whereas all analyses of inclusive
deep inelastic scattering yield significantly negative values of this quantity,
is known as the "strange quark polarization puzzle". We have analyzed the world
data on inclusive deep inelastic scattering, including the COMPASS 2010 proton
data on the spin asymmetries, and for the first time, the new extremely precise
JLab CLAS data on the proton and deuteron spin structure functions. Despite
allowing in our parametrization, for a possible sign change, our results
confirm that the inclusive data yield significantly negative values for the
polarized strange quark density.Comment: 8 pages, 3 figures, 3 tables; misprints for the values of
in page 5 correcte
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