948 research outputs found
Aluminium content of spanish infant formula
Aluminium toxicity has been relatively well documented in infants with impaired renal
function and premature neonates.
The aims of this study were to analyse the concentration of aluminium in the majority of
infant formulae sold commercially in Spain, to determine the influence of aluminium
content in the tap water in reconstituted powder formulae and to estimate the theoretical
toxic aluminium intake in comparison with the PTWI, and lastly, to discuss the possible
interactions of certain essential trace elements added to formulation with aluminium
according to type or main protein based infant formula.
A total of 82 different infant formulae from 9 different manufacturers were studied.
Sample digestion was simulated in a closed acid-decomposition microwave system.
Aluminium concentration was determined by atomic absorption spectrophotometry with
graphite furnace.
In general, the infant formulae studied provide an aluminium level higher than that found
in human milk, especially in the case of soya, preterm or hydrolysed casein-based
formulae.
Standard formulae provide lower aluminium intakes amounting to about 4 % PTWI.
Specialised and preterm formulae result in moderate intake (11 â 12 % and 8 â 10 %
PTWI, respectively). Soya formulae contribute the highest intake (15 % PTWI).
Aluminium exposure from drinking water used for powder formula reconstitution is not
considered a clear potential risk.
In accordance with the present state of knowledge about aluminium toxicity, it seems
prudent to call for continued efforts to standardise routine quality control and reduce
aluminium levels in infant formula as well as to keep the aluminium concentration under
300 g l-1 for all infant formulae, most specifically those formulae for premature and low
birth neonates
Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158 A GeV/c
Two-particle correlation functions of negatively charged hadrons from Pb-Pb
collisions at 158 GeV/c per nucleon have been measured by the WA97 experiment
at the CERN SPS. A Coulomb correction procedure that assumes an expanding
source has been implemented. Within the framework of an expanding thermalized
source model the size and dynamical state of the collision fireball at
freeze-out have been reconstructed as a function of the centrality of the
collision. Less central collisions exhibit a different dynamics than central
ones: both transverse and longitudinal expansion velocities are slower, the
expansion duration is shorter and the system freezes out showing smaller
dimensions and higher temperature.Comment: 22 pages, 11 figures, Te
Measurement of the hadronic photon structure function F_{2}^{Îł} at LEP2
The hadronic structure function of the photon F_{2}^{Îł} (x, QÂČ) is measured as a function of Bjorken x and of the photon virtuality QÂČ using deep-inelastic scattering data taken by the OPAL detector at LEP at eâșeâ» centre-of-mass energies from 183 to 209 GeV. Previous OPAL measurements of the x dependence of F_{2}^{Îł} are extended to an average QÂČ of ăQÂČă=780 GeVÂČ using data in the kinematic range 0.15<x<0.98. The QÂČ evolution of F_{2}^{Îł} is studied for 12.1<ăQÂČă<780 GeVÂČ using three ranges of x. As predicted by QCD, the data show positive scaling violations in F_{2}^{Îł} with F_{2}^{Îł} (QÂČ)/α = (0.08±0.02âșâ°Â·â°â”_â.ââ) + (0.13±0.01âșâ°Â·â°Âč_â.ââ) lnQÂČ, where QÂČ is in GeVÂČ, for the central x region 0.10â0.60. Several parameterisations of F_{2}^{Îł} are in qualitative agreement with the measurements whereas the quark-parton model prediction fails to describe the data
Measurement of the charm structure function F_{2,c)^{Îł} of the photon at LEP
The production of charm quarks is studied in deep-inelastic electronâphoton scattering using data recorded by the OPAL detector at LEP at nominal eâșeâ» centre-of-mass energies from 183 to 209 GeV. The charm quarks have been identified by full reconstruction of charged D* mesons using their decays into Dâ°Ï with the Dâ° observed in two decay modes with charged particle final states, KÏ and KÏÏÏ. The cross-section Ï^{D*} for production of charged D* in the reaction eâșeâ»âeâșeâ»D*Χ is measured in a restricted kinematical region using two bins in Bjorken x, 0.00140.1 the perturbative QCD calculation at next-to-leading order agrees perfectly with the measured cross-section. For x<0.1 the measured cross-section is 43.8±14.3±6.3±2.8 pb with a next-to-leading order prediction of 17.0âșÂČ·âč_â.â pb
Measurement of triple gauge boson couplings from WâșWâ» production at LEP energies up to 189 GeV
A measurement of triple gauge boson couplings is presented, based on W-pair data recorded by the OPAL detector at LEP during 1998 at a centre-of-mass energy of 189 GeV with an integrated luminosity of 183 pbâ»Âč. After combining with our previous measurements at centre-of-mass energies of 161â183 GeV we obtain Îș = 0.97_{-0.16}^{+0.20}, g_{1}^{z} = 0.991_{-0.057}^{+0.060} and λ = -0.110_{-0.055}^{+0.058}, where the errors include both statistical and systematic uncertainties and each coupling is determined by setting the other two couplings to their Standard Model values. These results are consistent with the Standard Model expectations
A new VME trigger processor for the NA57 experiment
The ALICE experiment will use a trigger concept requiring independent deadtimes for each sub-detector system, and with detector-specific past-future protection. These features are implemented in a new VME-based trigger processor for the NA57 experiment. Monitoring and diagnostic features of the new trigger processor are also described.List of Figures Figure 1:ALICE trigger logic diagram. Figure 2:Layout of the NA57 experiment. Figure 3:Schematic layout of NA57 VME central trigger processor. Figure 4:Example of a trigger definition script. </A
Search for Yukawa Production of a Light Neutral Higgs Boson at LEP
Within a Two-Higgs-Doublet Model (2HDM) a search for a light Higgs boson in
the mass range of 4-12 GeV has been performed in the Yukawa process e+e- -> b
bbar A/h -> b bbar tau+tau-, using the data collected by the OPAL detector at
LEP between 1992 and 1995 in e+e- collisions at about 91 GeV centre-of-mass
energy. A likelihood selection is applied to separate background and signal.
The number of observed events is in good agreement with the expected
background. Within a CP-conserving 2HDM type II model the cross-section for
Yukawa production depends on xiAd = |tan beta| and xihd = |sin alpha/cos beta|
for the production of the CP-odd A and the CP-even h, respectively, where tan
beta is the ratio of the vacuum expectation values of the Higgs doublets and
alpha is the mixing angle between the neutral CP-even Higgs bosons. From our
data 95% C.L. upper limits are derived for xiAd within the range of 8.5 to 13.6
and for xihd between 8.2 to 13.7, depending on the mass of the Higgs boson,
assuming a branching fraction into tau+tau- of 100%. An interpretation of the
limits within a 2HDM type II model with Standard Model particle content is
given. These results impose constraints on several models that have been
proposed to explain the recent BNL measurement of the muon anomalous magnetic
moment.Comment: 24 pages, 9 figures, Submitted to Euro. Phys. J.
Measurement of the Hadronic Cross-Section for the Scattering of Two Virtual Photons at LEP
The interaction of virtual photons is investigated using the reaction e+e- ->
e+e- hadrons based on data taken by the OPAL experiment at e+e- centre-of-mass
energies sqrt(s_ee)=189-209 GeV, for W>5 GeV and at an average Q^2 of 17.9
GeV^2. The measured cross-sections are compared to predictions of the Quark
Parton Model (QPM), to the Leading Order QCD Monte Carlo model PHOJET to the
NLO prediction for the reaction e+e- -> e+e-qqbar, and to BFKL calculations.
PHOJET, NLO e+e- -> e+e-qqbar, and QPM describe the data reasonably well,
whereas the cross-section predicted by a Leading Order BFKL calculation is too
large.Comment: 30 pages, 10 figures, Submitted to Eur.Phys.J.
Measurement of triple gauge boson couplings from WW production at LEP energies up to 189 GeV
A measurement of triple gauge boson couplings is presented, based on W-pair
data recorded by the OPAL detector at LEP during 1998 at a centre-of-mass
energy of 189 GeV with an integrated luminosity of 183 pb^-1. After combining
with our previous measurements at centre-of-mass energies of 161-183 GeV we
obtain k_g=0.97 +0.20 -0.16, g_1^z=0.991 +0.060 -0.057 and lambda_g=-0.110
+0.058 -0.055, where the errors include both statistical and systematic
uncertainties and each coupling is determined by setting the other two
couplings to their SM values. These results are consistent with the Standard
Model expectations.Comment: 28 pages, 8 figures, submitted to Eur. Phys. J.
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