21 research outputs found
Correlations in transverse momentum in pion-proton and kaon-proton collisions at 250 GeV/c
We have measured the second-order normalized differential factorial moments
as a function of the difference of transverse momentum () in \p^+
p and collisions at 250 GeV/. The second-order differential
factorial moments for like-charged pairs reveal a strong increase with
decreasing . In a small central rapidity window this increase is
described by a simple power law. Such a behavior, if interpreted as originating
from Bose-Einstein correlations, may indicate a structure of the transverse
spatial distribution of the source similar to that recently predicted by
Bia\l{}as and Peschanski for color-dipole emission in onium-onium scattering.
The power of the rise obtained in the fit agrees with the predicted value.Comment: Talk presented at the 7th Workshop on Multiparticle Production
``Correlations and Fluctuations'', Nijmegen, The Netherlands, 30th June-6th
July, 1996. Latex, 7 pages, uses epsfig.sty, pennames.sty (included), 1 eps
figur
A global reanalysis of nuclear parton distribution functions
We determine the nuclear modifications of parton distribution functions of
bound protons at scales GeV and momentum fractions
in a global analysis which utilizes nuclear hard process
data, sum rules and leading-order DGLAP scale evolution. The main improvements
over our earlier work {\em EKS98} are the automated minimization,
simplified and better controllable fit functions, and most importantly, the
possibility for error estimates. The resulting 16-parameter fit to the N=514
datapoints is good, . Within the error estimates
obtained, the old {\em EKS98} parametrization is found to be fully consistent
with the present analysis, with no essential difference in terms of
either. We also determine separate uncertainty bands for the nuclear gluon and
sea quark modifications in the large- region where they are not stringently
constrained by the available data. Comparison with other global analyses is
shown and uncertainties demonstrated. Finally, we show that RHIC-BRAHMS data
for inclusive hadron production in d+Au collisions lend support for a stronger
gluon shadowing at and also that fairly large changes in the gluon
modifications do not rapidly deteriorate the goodness of the overall fits, as
long as the initial gluon modifications in the region remain
small.Comment: 33 pages, 14 figure
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Self-assembly of ultra-small micelles from amphiphilic lipopeptoids
Poly(N-substituted glycine) “peptoids” constitute a promising class of peptide-mimetic materials. We introduce the self-assembly of lipopeptoids into spherical micelles ca. 5 nm in diameter as well as larger assemblies by varying the peptoid sequence design. Our results point to design rules for the self-assembly of peptoid nanostructures, enabling the creation of stable, ultra-small peptidomimetic nanospheres
Modelling of Effective Thermal Conductivity of Composites Filled with Core-Shell Fillers
An effective model to calculate thermal conductivity of polymer composites using core-shell fillers is presented, wherein a core material of filler grains is covered by a layer of a high-thermal-conductivity (HTC) material. Such fillers can provide a significant increase of the composite thermal conductivity by an addition of a small amount of the HTC material. The model employs the Lewis-Nielsen formula describing filled systems. The effective thermal conductivity of the core-shell filler grains is calculated using the Russel model for porous materials. Modelling results are compared with recent measurements made on composites filled with cellulose microbeads coated with hexagonal boron nitride (h-BN) platelets and good agreement is demonstrated. Comparison with measurements made on epoxy composites, using silver-coated glass spheres as a filler, is also provided. It is demonstrated how the modelling procedure can improve understanding of properties of materials and structures used and mechanisms of thermal conduction within the composite
The effects of artificial light at night (ALAN) on the gaping activity and feeding of mussels
Artificial Light at Night (ALAN) is a common environmental pollutant which affects >22 % of the world's coastlines. However, the impact of ALAN wavelengths on coastal organisms is under-investigated. Here, we tested the impact of red, green, and white ALAN on the gaping activity and phytoplankton consumption of Mytilus edulis mussels and compared these to dark night. Mussels exhibited a semi-diel activity pattern. Although ALAN did not significantly affect the time open nor the phytoplankton consumption, it did have a colour-specific effect on the gaping frequency with red and white ALAN resulting in lower activity compared to the dark night. Green ALAN caused higher gaping frequency and a negative relationship between consumption and proportion of time open compared to the other treatments. Our findings suggest colour-specific ALAN effects on mussels and call for further investigation on the associated physiological mechanisms and potential ecological consequences