5,850 research outputs found
Arabidopsis PEN3/PDR8, an ATP binding cassette transporter, contributes to nonhost resistance to inappropriate pathogens that enter by direct penetration
Prompt neutrino fluxes in the atmosphere with PROSA parton distribution functions
Effects on atmospheric prompt neutrino fluxes of present uncertainties
affecting the nucleon composition are studied by using the PROSA fit to parton
distribution functions (PDFs). The PROSA fit extends the precision of the PDFs
to low x, which is the kinematic region of relevance for high-energy neutrino
production, by taking into account LHCb data on charm and bottom
hadroproduction. In the range of neutrino energies explored by present Very
Large Volume Neutrino Telescopes, it is found that PDF uncertainties are far
smaller with respect to those due to renormalization and factorization scale
variation and to assumptions on the cosmic ray composition, which at present
dominate and limit our knowledge of prompt neutrino fluxes. A discussion is
presented on how these uncertainties affect the expected number of atmospheric
prompt neutrino events in the analysis of high-energy events characterized by
interaction vertices fully contained within the instrumented volume of the
detector, performed by the IceCube collaboration.Comment: 36 pages, 17 figures, 1 tabl
A Critical Appraisal and Evaluation of Modern PDFs
We review the present status of the determination of parton distribution
functions (PDFs) in the light of the precision requirements for the LHC in Run
2 and other future hadron colliders. We provide brief reviews of all currently
available PDF sets and use them to compute cross sections for a number of
benchmark processes, including Higgs boson production in gluon-gluon fusion at
the LHC. We show that the differences in the predictions obtained with the
various PDFs are due to particular theory assumptions made in the fits of those
PDFs. We discuss PDF uncertainties in the kinematic region covered by the LHC
and on averaging procedures for PDFs, such as advocated by the PDF4LHC15 sets,
and provide recommendations for the usage of PDF sets for theory predictions at
the LHC.Comment: 70 pages pdflatex, 19 figures, 17 tables; final versio
DIS structure functions and the double-spin asymmetry in rho(0) electroproduction within a Regge approach
The proton, neutron and deuteron structure functions F2(x,Q2) and g1(x,Q2), measured at intermediate Q2, are analyzed within a Regge approach. This analysis serves to fix the parameters of this scheme which are then used to calculate, in a unified Regge approach, the properties of ρ0 meson electroproduction on the proton and the deuteron. In this way, the double-spin asymmetry observed at HERMES in ρ0 electroproduction on the proton, can be related to the anomalous behavior of the flavor-singlet part of the spin-dependent structure function g1(x,Q2) at small x
Reading sentences with a late closure ambiguity: does semantic information help?
Stowe (1989) reported that semantic information eliminates garden paths in sentences with the direct-object vs. subject ambiguity, such as Even before the police stopped the driver was very frightened. Three experiments are presented which addressed some methodological problems in Stowe's study. Experiment 1, using a word-by-word, self-paced reading task with grammaticality judgements, manipulated animacy of the first subject noun while controlling for the plausibility of the transitive action. The results suggest that initial sentence analysis is not guided by animacy. Experiment 2 and 3, using the self-paced task with grammaticality judgements and eye-tracking, varied the plausibility of the direct-object nouns to test revision effects. Plausibility was found to facilitate revision without fully eliminating garden paths, in line with various revision models. The findings support the view of a sentence processing system relying heavily on syntactic information, with semantic information playing a weaker role both in initial analysis and during revision, thus supporting serial, syntax-first models and ranked-parallel models relying on structural criteria
Moonlighting function of Phytochelatin synthase1 in extracellular defense against fungal pathogens
Phytochelatin synthase (PCS) is a key component of heavy metal detoxification in plants. PCS catalyzes both the synthesis of the peptide phytochelatin from glutathione and the degradation of glutathione conjugates via peptidase activity. Here, we describe a role for PCS in disease resistance against plant pathogenic fungi. The pen4 mutant, which is allelic to cadmium insensitive1 (cad1/pcs1) mutants, was recovered from a screen for Arabidopsis mutants with reduced resistance to the nonadapted barley fungal pathogen Blumeria graminis f. sp. hordei. PCS1, which is found in the cytoplasm of cells of healthy plants, translocates upon pathogen attack and colocalizes with the PEN2 myrosinase on the surface of immobilized mitochondria. pcs1 and pen2 mutant plants exhibit similar metabolic defects in the accumulation of pathogen-inducible indole glucosinolate-derived compounds, suggesting that PEN2 and PCS1 act in the same metabolic pathway. The function of PCS1 in this pathway is independent of phytochelatin synthesis and deglycination of glutathione conjugates, as catalytic-site mutants of PCS1 are still functional in indole glucosinolate metabolism. In uncovering a peptidase-independent function for PCS1, we reveal this enzyme to be a moonlighting protein important for plant responses to both biotic and abiotic stresses
FOTODIODA OPARTA NA EPITAKSJALNYM FOSFORKU GALU O ZWIĘKSZONEJ WRAŻLIWOŚCI PRZY DŁUGOŚCI FALI 254 nm
The paper shows the results of the development of a photodiode technology based on gallium phosphide structure n+-n-GaP-Au with high sensitivity. It provides the ion etching of the surface of the gallium phosphide before an application of a leading electrode of gold. The barrier layer of a 20 nm thick gold is applied to the substrate in the magnetic field of GaP. When forming the contact with the reverse side of the indium substrate at 600°C, there occurs the annealing of the gold barrier layer. At the maximum of the spectral characteristics obtained by the photodiode, it has a sensitivity of 0.13 A/W, and at a wavelength of 254 nm – about 0.06 A/W. The dynamic range of the photodiode is not less than 107.Artykuł pokazuje rezultaty rozwoju technologicznego fotodiody opartej na fosforku galu o strukturze n+-n-GaP-Au o wysokiej czułości. Umożliwia to wytrawianie jonowe powierzchni fosforku galu, zanim zastosowana zostanie elektroda przewodząca wykonana ze złota. Złota warstwa barierowa o grubości 20 nm jest nakładana na podłoże GaP w polu magnetycznym. Gdy powstaje styk z tyłu podłoża indowego w temperaturze 600°C, złota warstwa barierowa jest wyżarzana. Przy maksymalnej charakterystyce spektralnej uzyskanej przez fotodiodę, ma ona czułość 0,13 A/W, a przy długości fali 254 nm – około 0,06 A / W. Zakres dynamiczny fotodiody wynosi co najmniej 107
F2c at low x
We study the heavy-quark contributions to the proton structure function
F2(x,Q2) at next-to-leading order using compact formulas at small values of
Bjorken's x variable. The formulas provide a good agreement with the modern
HERA data for F2c(x,Q2).Comment: 8 pages, 1 figure, presented on the XIV International Conference on
Symmetry Methods in Physics (SYMPHYS-XIV), Tsakhkadzor, Armenia, August 16 -
22, 201
Triquark correlations and pentaquarks in a QCD sum rule approach
The role of quark correlations in the description of hadron dynamics in many
domains of physics, from low energy dynamics to very hot(dense) systems, is
being appreciated. Strong correlations of two quarks (diquark) have been widely
investigated in this respect. Recently, we have proposed a dynamical scheme to
describe the pentaquark in which also three quark correlations
(triquark) were instrumental in producing a low mass exotic state. We perform a
study, within the QCD sum rule approach including OPE and direct instanton
contributions, of triquark correlations and obtain two quasi-bound light
color quark clusters of 800 MeV and 930 MeV respectively.Comment: 11 pages, 9 figures, corrected typos, reference added, introduction
and conclusions modified slightl
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