829 research outputs found
Mapping spaces and automorphism groups of toric noncommutative spaces
We develop a sheaf theory approach to toric noncommutative geometry which allows us to formalize the concept of mapping spaces between two toric noncommutative spaces. As an application we study the 'internalized' automorphism group of a toric noncommutative space and show that its Lie algebra has an elementary description in terms of braided derivations
Dissociation of virtual photons in events with a leading proton at HERA
The ZEUS detector has been used to study dissociation of virtual photons in
events with a leading proton, gamma^* p -> X p, in e^+p collisions at HERA. The
data cover photon virtualities in two ranges, 0.03<Q^2<0.60 GeV^2 and 2<Q^2<100
GeV^2, with M_X>1.5 GeV, where M_X is the mass of the hadronic final state, X.
Events were required to have a leading proton, detected in the ZEUS leading
proton spectrometer, carrying at least 90% of the incoming proton energy. The
cross section is presented as a function of t, the squared four-momentum
transfer at the proton vertex, Phi, the azimuthal angle between the positron
scattering plane and the proton scattering plane, and Q^2. The data are
presented in terms of the diffractive structure function, F_2^D(3). A
next-to-leading-order QCD fit to the higher-Q^2 data set and to previously
published diffractive charm production data is presented
Observation of Scaling Violations in Scaled Momentum Distributions at HERA
Charged particle production has been measured in deep inelastic scattering
(DIS) events over a large range of and using the ZEUS detector. The
evolution of the scaled momentum, , with in the range 10 to 1280
, has been investigated in the current fragmentation region of the Breit
frame. The results show clear evidence, in a single experiment, for scaling
violations in scaled momenta as a function of .Comment: 21 pages including 4 figures, to be published in Physics Letters B.
Two references adde
D* Production in Deep Inelastic Scattering at HERA
This paper presents measurements of D^{*\pm} production in deep inelastic
scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The
data have been taken with the ZEUS detector at HERA. The decay channel
(+ c.c.) has been used in the study. The
cross section for inclusive D^{*\pm} production with
and is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region
{ GeV and }. Differential cross
sections as functions of p_T(D^{*\pm}), and are
compared with next-to-leading order QCD calculations based on the photon-gluon
fusion production mechanism. After an extrapolation of the cross section to the
full kinematic region in p_T(D^{*\pm}) and (D^{*\pm}), the charm
contribution to the proton structure function is
determined for Bjorken between 2 10 and 5 10.Comment: 17 pages including 4 figure
Loss of DNMT1o Disrupts Imprinted X Chromosome Inactivation and Accentuates Placental Defects in Females
The maintenance of key germline derived DNA methylation patterns during preimplantation development depends on stores of DNA cytosine methyltransferase-1o (DNMT1o) provided by the oocyte. Dnmt1omat-/- mouse embryos born to Dnmt1Δ1o/Δ1o female mice lack DNMT1o protein and have disrupted genomic imprinting and associated phenotypic abnormalities. Here, we describe additional female-specific morphological abnormalities and DNA hypomethylation defects outside imprinted loci, restricted to extraembryonic tissue. Compared to male offspring, the placentae of female offspring of Dnmt1Δ1o/Δ1o mothers displayed a higher incidence of genic and intergenic hypomethylation and more frequent and extreme placental dysmorphology. The majority of the affected loci were concentrated on the X chromosome and associated with aberrant biallelic expression, indicating that imprinted X-inactivation was perturbed. Hypomethylation of a key regulatory region of Xite within the X-inactivation center was present in female blastocysts shortly after the absence of methylation maintenance by DNMT1o at the 8-cell stage. The female preponderance of placental DNA hypomethylation associated with maternal DNMT1o deficiency provides evidence of additional roles beyond the maintenance of genomic imprints for DNA methylation events in the preimplantation embryo, including a role in imprinted X chromosome inactivation. © 2013 McGraw et al
Distribution of sensitivity to common botryticides in Lombardy
On grapevine, grey mould caused by Botrytis cinerea Pers. induces serious yield losses and unpleasant changes in the qualitative characteristics of berry content. Fungicides are usually applied in order to control B. cinerea but their repeated use in vineyard can select resistant strains of the pathogen.
Aim of the present work is not only to monitor the sensitivity distribution of the pathogen strains to the botryticides most commonly used in vineyard, but also the possible correlation between the sensitivity level and both the mating type and the presence of transposons Boty and Flipper.
During 2011, 20 strains were randomnly isolated from symptomatic samples collected in 4 vineyards selected in each of the main viticultural provinces in Lombardy, Brescia, Mantova, Pavia and Sondrio. An untreated vineyard was included in the survey. The 320 strains isolated in Lombardy were tested for their sensitivity to boscalid, fenhexamid, cyprodinil and fludioxonil, their mating type and the presence of transposons. The Resistance Factor, RF, (EC50 of the selected strain/average EC50 in the untreated vineyard) was calculated for the strains showing high EC50. RFs > 10 indicate a reduced sensitivity.
The average EC50 observed in Lombardy for boscalid, fenhexamid and fludioxonil were similar to those calculated for B. cinerea in Europe, while higher values of this parameter were obtained for cyprodinil. No remarkable differences were observed in the EC50 distribution in the 4 provinces, apart from the higher values for cyprodinil and fludioxonil recorded in Pavia. RFs > 10 characterized 7, 12 and 5 strains respectively for boscalid cyprodinil and fludioxonil and 5 isolated showed a reduced multi drug sensitivity. The presence of Boty either alone or together with Flipper seems to be associated with higher RFs concerning all the tested fungicides. Association between mating type and fungicide sensitivity is less defined. From these data, B. cinerea populations in Lombardy seem to be characterized by an adequate sensitivity against botryticides. The strains showing a reduced sensitivity need to be further characterized, in particular for their fitness
Tumor control in ion beam radiotherapy with different ions in the presence of hypoxia: an oxygen enhancement ratio model based on the microdosimetric kinetic model
Measurement of Jet Shapes in Photoproduction at HERA
The shape of jets produced in quasi-real photon-proton collisions at
centre-of-mass energies in the range GeV has been measured using the
hadronic energy flow. The measurement was done with the ZEUS detector at HERA.
Jets are identified using a cone algorithm in the plane with a
cone radius of one unit. Measured jet shapes both in inclusive jet and dijet
production with transverse energies GeV are presented. The jet
shape broadens as the jet pseudorapidity () increases and narrows
as increases. In dijet photoproduction, the jet shapes have been
measured separately for samples dominated by resolved and by direct processes.
Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct
processes describe well the measured jet shapes except for the inclusive
production of jets with high and low . The observed
broadening of the jet shape as increases is consistent with the
predicted increase in the fraction of final state gluon jets.Comment: 29 pages including 9 figure
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