342 research outputs found
Correlation measurements in high-multiplicity events
Requirements for correlation measurements in high--multiplicity events are
discussed. Attention is focussed on detection of so--called hot spots,
two--particle rapidity correlations, two--particle momentum correlations (for
quantum interferometry) and higher--order correlations. The signal--to--noise
ratio may become large in the high--multiplicity limit, allowing meaningful
single--event measurements, only if the correlations are due to collective
behavior.Comment: MN 55455, 20 pages, KSUCNR-011-92 and TPI-MINN-92/47-T (revised).
Revised to correct typo in equation (30), and to fill in a few steps in
calculations. Now published as Phys. Rev. C 47 (1993) 232
Polymer coated cerium oxide nanoparticles as oxidoreductase-like catalysts
Cerium oxide nanoparticles have been shown to mimic oxidoreductase enzymes by
catalyzing the decomposition of organic substrates and reactive oxygen species.
This mimicry can be found in superoxide radicals and hydrogen peroxides,
harmful molecules produced in oxidative stress asso-ciated diseases. Despite
the fact that nanoparticle functionalization is mandatory in the context of
nanomedicine, the influence of polymer coatings on their enzyme-like catalytic
activity is poorly understood. In this work, six polymer coated cerium oxide
nanoparticles are prepared by associa-tion of 7.8 nm cerium oxide cores with
two poly(sodium acrylate) and four poly(ethylene glycol) (PEG) grafted
copolymers with different terminal or anchoring end groups, such as phosphonic
acids. The superoxide dismutase-, catalase-, peroxidase- and oxidase-like
catalytic activities of the coated nanoparticles were systematically studied.
It is shown that the polymer coatings do not af-fect the superoxide
dismutase-like, impair the catalase-like and oxidase-like and surprisingly
im-proves peroxidase-like catalytic activities of cerium oxide nanoparticles.
It is also demonstrated that the particles coated with the PEG-grafted
copolymers perform better than the poly(acrylic acid) coated ones as
oxidoreductase-like enzymes, a result that confirms the benefit of having
phosphon-ic acids as anchoring groups at the particle surface.Comment: 23 pages, 8 figures, 3 table
Exclusive Production of Higgs Bosons in Hadron Colliders
We study the exclusive, double--diffractive production of the Standard Model
Higgs particle in hadronic collisions at LHC and FNAL (upgraded) energies. Such
a mechanism would provide an exceptionally clean signal for experimental
detection in which the usual penalty for triggering on the rare decays of the
Higgs could be avoided. In addition, because of the color singlet nature of the
hard interaction, factorization is expected to be preserved, allowing the
cross--section to be related to similar hard--diffractive events at HERA.
Starting from a Fock state expansion in perturbative QCD, we obtain an estimate
for the cross section in terms of the gluon structure functions squared of the
colliding hadrons. Unfortunately, our estimates yield a production rate well
below what is likely to be experimentally feasible.Comment: 17 pages, RevTeX file, four uufiled PostScript figures. UMPP #94-177.
(Revised version. Some mistakenly missing Feynman diagrams are now added.
Results do not change qualitatively. Paper reorganized.
Accommodating 'others'?: housing dispersed, forced migrants in the UK
Utilising insights from a qualitative study in the city of Leeds (UK), this paper considers issues related to the housing of dispersed forced migrants. The term 'dispersed forced migrants' is used here as a general label to include four groups of international migrants (i.e. refugees, asylum seekers, those with humanitarian protection status and failed asylum seekers) who have previously been dispersed, on a no choice basis, to a variety of locations across the UK under the requirements of the Immigration and Asylum Act (1999). The tiering of housing entitlement that exists within the generic population of dispersed forced migrants (a consequence of the particular socio-legal status assigned to individuals), and its role in rendering migrants susceptible to homelessness is outlined. The adequacy/standard of accommodation made available to forced migrants is also discussed. It is concluded that current arrangements fail to meet the basic housing needs of many forced migrants. Any future improvement in this situation will require a significant shift in government policy
- âŠ