3,591 research outputs found
Measurement bias in the HICP: what do we know, and what do we need to know?
The Harmonized Index Of Consumer Prices (HICP) is the primary measure of inflation in the euro area, and plays a central role in the policy deliberations of the European Central Bank (ECB). Among the rationales given for defining price stability as prevailing at some positive measured inflation rate is the possibility that the HICP as published incorporates measurement errors of one sort or another that may cause it to systematically overstate the true rate of inflation in the euro area. The purpose of this paper is to review what is known about the scope of measurement error in the HICP. We conclude that given the scant research on price measurement issues in the EU and the ongoing improvements in the HICP, there is almost no scientific basis at this time for a point (or even an interval) estimate of a positive bias in the HICP. JEL Classification: C43, E31Harmonized Index of Consumer Prices, HICP, measurement error
Radiative heat transfer in 2D Dirac materials
We compute the radiative heat transfer between two sheets of 2D Dirac
materials, including topological Chern insulators and graphene, within the
framework of the local approximation for the optical response of these
materials. In this approximation, which neglects spatial dispersion, we derive
both numerically and analytically the short-distance asymptotic of the
near-field heat transfer in these systems, and show that it scales as the
inverse of the distance between the two sheets. Finally, we discuss the
limitations to the validity of this scaling law imposed by spatial dispersion
in 2D Dirac materials.Comment: 15 pages, 4 figures. Updated version including corrected analysis of
the far-field regim
Genetic diversity and selection in three plasmodium vivax merozoite surface protein 7 (pvmsp-7) genes in a colombian population
A completely effective vaccine for malaria (one of the major infectious diseases worldwide) is not yet available; different membrane proteins involved in parasite-host interactions have been proposed as candidates for designing it. It has been found that proteins encoded by the merozoite surface protein (msp)-7 multigene family are antibody targets in natural infection; the nucleotide diversity of three Pvmsp-7 genes was thus analyzed in a Colombian parasite population. By contrast with P. falciparum msp-7 loci and ancestral P. vivax msp-7 genes, specie-specific duplicates of the latter specie display high genetic variability, generated by single nucleotide polymorphisms, repeat regions, and recombination. At least three major allele types are present in Pvmsp-7C, Pvmsp-7H and Pvmsp-7I and positive selection seems to be operating on the central region of these msp-7 genes. Although this region has high genetic polymorphism, the C-terminus (Pfam domain ID: PF12948) is conserved and could be an important candidate when designing a subunit-based antimalarial vaccine
miRNA/phasiRNA mediated regulation of plant defense response against P. syringae
Gene silencing is a mechanism of regulation of gene expression where the small RNAs (sRNAs) are key components for giving specificity to the system. In plants, two main types of noncoding small RNA molecules have been found: microRNAs (miRNAs) and small interfering RNAs (siRNAs). DCL proteins acting on large RNA precursors produce the mature forms of sRNAs (20-24nt) that can act as negative regulators of gene expression. In recent years, the role of miRNAs in regulation of gene expression in plant responses against bacterial pathogens is becoming clearer. Comparisons carried out in our lab between expression profiles of different Arabidopsis thaliana mutants affected in gene silencing, and plants challenged with Pseudomonas syringae pathovar tomato DC3000, led us to identify a set of uncharacterized R genes, belonging to the TIR-NBS-LRR gene family, as differentially expressed in these conditions. Through the use of bioinformatics tools, we found a miRNA* of 22 nt putatively responsible for down-regulating expression of these R genes. We have validated this regulation, and have also established that the corresponding pri-miRNA is down-regulated upon PAMPs or bacteria perception. Using GUS reporters, we have characterized the expression pattern of both pri-miRNA and its best target R genes. We demonstrate that plants with altered levels of miRNA* (knockdown or overexpression lines) exhibit altered PTI-associated phenotypes, supporting a role for this miRNA* in the defence response against this bacterial pathogen. Finally, we identify phasiRNAs that arise from the transcript of one of the R target genes in a miRNA*-RDR6-DCL4-dependent manner.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Few-body decay and recombination in nuclear astrophysics
Three-body continuum problems are investigated for light nuclei of
astrophysical relevance. We focus on three-body decays of resonances or
recombination via resonances or the continuum background. The concepts of
widths, decay mechanisms and dynamic evolution are discussed. We also discuss
results for the triple decay in connection with resonances and
density and temperature dependence rates of recombination into light nuclei
from -particles and neutrons.Comment: 9 pages, 8 figures. Proceedings of the 21st European Few Body
Conference held in Salamanca (Spain) in August-September 201
Direct and sequential radiative three-body reaction rates at low temperatures
We investigate the low-temperature reaction rates for radiative capture
processes of three particles. We compare direct and sequential capture
mechanisms and rates using realistic phenomenological parametrizations of the
corresponding photodissociation cross sections.Energy conservation prohibits
sequential capture for energies smaller than that of the intermediate two-body
structure. A finite width or a finite temperature allows this capture
mechanism. We study generic effects of positions and widths of two- and
three-body resonances for very low temperatures. We focus on nuclear reactions
relevant for astrophysics, and we illustrate with realistic estimates for the
-- and -- radiative capture
processes. The direct capture mechanism leads to reaction rates which for
temperatures smaller than 0.1 GK can be several orders of magnitude larger than
those of the NACRE compilation.Comment: To be published in European Physical Journal
LkH 225 (V1318 Cyg) South in Outburst
© 2022 The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/Magakian et al. called attention to the current bright state of LkHα 225 South, a well-known highly embedded,intermediate-mass young stellar object that over the past two decades has brightened visually from >20m to <13m.We present recent optical photometric monitoring showing colorless, nonsinusoidal, periodic brightnessoscillations occurring every 43 days with amplitude âŒ0.7 mag. We also present new flux-calibrated optical andnear-infrared spectroscopy, which we model in terms of a Keplerian accretion disk, and high-dispersion spectrathat demonstrate similarity to some categories of âmixed-temperatureâ accretion-outburst objects. At bluewavelengths, LkHα 225 South has a pure absorption spectrum and is a good spectral match to the FU Ori starsV1515 Cyg and V1057 Cyg. At red optical and infrared wavelengths, however, the spectrum is more similar toGaia 19ajj, showing emission in TiO, CO, and metals. Sr II absorption indicates a low-surface-gravity atmosphere.There are also signatures of a strong wind/outflow. LkHα 225 South was moderately bright in the early 1950s aswell as in the late 1980s, with evidence for deep fades during intervening epochs. The body of evidence suggeststhat LkHα 225 South is another case of a source with episodically enhanced accretion that causes brightening byorders of magnitude, and development of a hot absorption spectrum and warm wind. It is similar to Gaia 19ajj, butalso reminiscent in its long brightening time and brightness oscillation near peak to the embedded sources L1634IRS7 and ESO Ha 99.Peer reviewe
Conformational analysis of a TADDOL-based phosphoramidite P,N ligand in a palladium(II) η3-Ï-allyl complex
Highlights Two lowest energy conformers differ in allyl conformation, conformer with exo allyl having lower energy. Lowest energy conformer has âchairâ conformation of 7-membered ring and âedge-on/face-on/face-on/edge-onâ array of pH groups. Next lowest energy conformer with exo allyl has alternating âedge-on/face-onâ arrangement and âtwistâ 7-membered ring. Changes in âchair/twistâ conformations with different substrates is possible due to 2.4âŻkcal/mol energy difference. These results explain stereochemical outcome of the reaction, and will guide design of new catalysts. Abstract The most stable conformations of a TADDOL-based phosphoramidite P,N ligand coordinated to a palladium(II) η3-Ï-allyl fragment have been investigated using molecular mechanical and quantum mechanical calculations. The conformational analysis initially generated 53 unique structures within 5âŻkcal/mol and subsequent geometry optimization narrowed the number of low-energy conformers down to 13. The two lowest energy conformers differ mainly in the conformation of the allyl group. The conformer with an endo allyl group has a slightly higher relative energy than the conformer with an exo allyl group. Comparison of the main geometric parameters around the Pd(II) metal center in the two lowest energy conformers with the available X-ray single crystal structures of Pd(II) η3-Ï-allyl complexes of P,N ligands shows a good agreement in both the bond lengths and angles. The lowest energy structure has a âchairâ conformation of the seven-membered phospha-dioxa-cycloheptane ring and âedge-on/face-on/face-on/edge-onâ arrangement of the phenyl rings. The next lowest energy conformer with an exo allyl group has a âtwistâ conformation of the seven-membered ring and alternating âedge-onâ and âface-onâ arrangement of the phenyl rings as anticipated from the Knowles âedge-on/face-onâ concept. The results of this study support published hypotheses regarding the origin of the chiral induction in the enantioselective Pd(0) catalyzed intramolecular allylic alkylation reaction by the repulsive interactions between one of the phenyl groups in the seven-membered ring in the lowest energy conformer of the ligand with the substrate. As such, the results of this research can be used to guide the synthesis of new and improved variants of this important catalyst family
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