576 research outputs found
Retail Price Dynamics and Retailer Heterogeneity: UK Evidence
We examine retailer heterogeneity in price adjustment in UK supermarkets. Considerable variation in the price change frequency of identically bar-coded products among retail chains is found. Decomposition analysis suggests that price adjustment is evenly split between sales and reference prices with substantive variation across retailers
Precise QCD predictions for the production of a Z boson in association with a hadronic jet
We compute the cross section and differential distributions for the production of a Z boson in association with a hadronic jet to next-to-next-to-leading order (NNLO) in perturbative QCD, including the leptonic decay of the Z boson. We present numerical results for the transverse momentum and rapidity distributions of both the Z boson and the associated jet at the LHC. We find that the NNLO corrections increase the NLO predictions by approximately 1% and significantly reduce the scale variation uncertainty
The NNLO QCD corrections to Z boson production at large transverse momentum
The transverse momentum distribution of massive neutral vector bosons can be measured to high accuracy at hadron colliders. The transverse momentum is caused by a partonic recoil, and is determined by QCD dynamics. We compute the single and double-differential transverse momentum distributions for fully inclusive Z/Îłâ production including leptonic decay to next-to-next-to-leading order (NNLO) in perturbative QCD. We also compute the same distributions normalised to the cross sections for inclusive Z/Îłâ production, i.e. integrated over the transverse momentum of the lepton pair. We compare our predictions for the fiducial cross sections to the 8 TeV data set from the ATLAS and CMS collaborations, which both observed a tension between data and NLO theory predictions, using the experimental cuts and binning. We find that the inclusion of the NNLO QCD effects does not fully resolve the tension with the data for the unnormalised pZT distribution. However, we observe that normalising the NNLO Z-boson transverse momentum distribution by the NNLO Drell-Yan cross section substantially improves the agreement between experimental data and theory, and opens the way for precision QCD studies of this observable
and Polarizabilities from {} Data on the Base of S-Matrix Approach
We suggest the most model-independent and simple description of the
process near threshold in framework of S-matrix
approach. The amplitudes contain the pion polarizabilities and rather
restricted information about interaction. Application of these
formulae for description of MARK-II \cite{M2} and Crystal Ball \cite{CB} data
gives: ,
(in units system ) at the experimental values of scattering lengths. Both
values are compartible with current algebra predictions.Comment: LaTeX, 14 pages plus 6 figures (not included, available upon request)
, ISU-IAP.Th93-03, Irkuts
3-Fluoro-4-hydroxyprolines:Synthesis, conformational analysis and stereoselective recognition by the VHL E3 ubiquitin ligase for targeted protein degradation
Hydroxylation and
fluorination of proline alters the pyrrolidine
ring pucker and the trans:cis amide bond ratio in a stereochemistry-dependent
fashion, affecting molecular recognition of proline-containing molecules
by biological systems. While hydroxyprolines and fluoroprolines are
common motifs in medicinal and biological chemistry, the synthesis
and molecular properties of prolines containing both modifications,
i.e., fluoro-hydroxyprolines, have not been described. Here we present
a practical and facile synthesis of all four diastereoisomers of 3-fluoro-4-hydroxyprolines
(F-Hyps), starting from readily available 4-oxo-l-proline
derivatives. Small-molecule X-ray crystallography, NMR spectroscopy,
and quantum mechanical calculations are consistent with fluorination
at C<sup>3</sup> having negligible effects on the hydrogen bond donor
capacity of the C<sup>4</sup> hydroxyl, but inverting the natural
preference of Hyp from C<sup>4</sup>-exo to C<sup>4</sup>-endo pucker.
In spite of this, F-Hyps still bind to the von HippelâLindau
(VHL) E3 ligase, which naturally recognizes C<sup>4</sup>-exo Hyp
in a stereoselective fashion. Co-crystal structures and electrostatic
potential calculations support and rationalize the observed preferential
recognition for (3<i>R</i>,4<i>S</i>)-F-Hyp over
the corresponding (3<i>S</i>,4<i>S</i>) epimer
by VHL. We show that (3<i>R</i>,4<i>S</i>)-F-Hyp
provides bioisosteric Hyp substitution in both hypoxia-inducible factor
1 alpha (HIF-1α) substrate peptides and peptidomimetic ligands
that form part of PROTAC (proteolysis targeting chimera) conjugates
for targeted protein degradation. Despite a weakened affinity, Hyp
substitution with (3<i>S</i>,4<i>S</i>)-F-Hyp
within the PROTAC MZ1 led to Brd4-selective cellular degradation at
concentrations >100-fold lower than the binary <i>K</i><sub>d</sub> for VHL. We anticipate that the disclosed chemistry
of 3-fluoro-4-hydroxyprolines
and their application as VHL ligands for targeted protein degradation
will be of wide interest to medicinal organic chemists, chemical biologists,
and drug discoverers alike
Photon-Photon Scattering, Pion Polarizability and Chiral Symmetry
Recent attempts to detect the pion polarizability via analysis of
measurements are examined. The connection
between calculations based on dispersion relations and on chiral perturbation
theory is established by matching the low energy chiral amplitude with that
given by a full dispersive treatment. Using the values for the polarizability
required by chiral symmetry, predicted and experimental cross sections are
shown to be in agreement.Comment: 21 pages(+10 figures available on request), LATEX, UMHEP-38
High-Speed Cylindrical Collapse of Two Perfect Fluids
In this paper, the study of the gravitational collapse of cylindrically
distributed two perfect fluid system has been carried out. It is assumed that
the collapsing speeds of the two fluids are very large. We explore this
condition by using the high-speed approximation scheme. There arise two cases,
i.e., bounded and vanishing of the ratios of the pressures with densities of
two fluids given by . It is shown that the high-speed approximation
scheme breaks down by non-zero pressures when are bounded
below by some positive constants. The failure of the high-speed approximation
scheme at some particular time of the gravitational collapse suggests the
uncertainity on the evolution at and after this time. In the bounded case, the
naked singularity formation seems to be impossible for the cylindrical two
perfect fluids. For the vanishing case, if a linear equation of state is used,
the high-speed collapse does not break down by the effects of the pressures and
consequently a naked singularity forms. This work provides the generalisation
of the results already given by Nakao and Morisawa [1] for the perfect fluid.Comment: 11 pages, 1 figure, accepted for publication in Gen. Rel. Gra
Energetics of the Einstein-Rosen spacetime
A study covering some aspects of the Einstein--Rosen metric is presented. The
electric and magnetic parts of the Weyl tensor are calculated. It is shown that
there are no purely magnetic E--R spacetimes, and also that a purely electric
E--R spacetime is necessarily static. The geodesics equations are found and
circular ones are analyzed in detail. The super--Poynting and the
``Lagrangian'' Poynting vectors are calculated and their expressions are found
for two specific examples. It is shown that for a pulse--type solution, both
expressions describe an inward radially directed flow of energy, far behind the
wave front. The physical significance of such an effect is discussed.Comment: 19 pages Latex.References added and updated.To appear in
Int.J.Theor.Phy
Characteristic cohomology of -form gauge theories
The characteristic cohomology for an arbitrary set of free
-form gauge fields is explicitly worked out in all form degrees ,
where is the spacetime dimension. It is shown that this cohomology is
finite-dimensional and completely generated by the forms dual to the field
strengths. The gauge invariant characteristic cohomology is also computed. The
results are extended to interacting -form gauge theories with gauge
invariant interactions. Implications for the BRST cohomology are mentioned.Comment: Latex file, no figures, 44 page
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