4,978 research outputs found
A framework for second-order parton showers
A framework is presented for including second-order perturbative corrections
to the radiation patterns of parton showers. The formalism allows to combine
O(alphaS^2)-corrected iterated 2->3 kernels for "ordered" gluon emissions with
tree-level 2->4 kernels for "unordered" ones. The combined Sudakov evolution
kernel is thus accurate to O(alphaS^2). As a first step towards a full-fledged
implementation of these ideas, we develop an explicit implementation of 2->4
shower branchings in this letter.Comment: 11 pages, 3 figure
Higher-order hadronic and heavy-lepton contributions to the anomalous magnetic moment
We report about recent results obtained for the muon anomalous magnetic
moment. Three-loop kernel functions have been computed to obtain the
next-to-next-to-leading-order hadronic vacuum polarization contributions. The
numerical result, , is of
the same order of magnitude as the current uncertainty from the hadronic
contributions. For heavy-lepton corrections, analytical results are obtained at
four-loop order and compared with the known results.Comment: Contribution to the proceedings of Loops and Legs in Quantum Field
Theory, 27 April - 2 May 2014, Weimar, German
TeV Lepton Number Violation: From Neutrinoless Double Beta Decay to the LHC
We analyze the sensitivity of next-generation tonne-scale neutrinoless double
-decay () experiments and searches for same-sign
di-electrons plus jets at the Large Hadron Collider to TeV scale lepton number
violating interactions. Taking into account previously unaccounted for physics
and detector backgrounds at the LHC, renormalization group evolution, and
long-range contributions to nuclear matrix elements, we find
that the reach of tonne-scale generally exceeds that of the
LHC. However, for a range of heavy particle masses near the TeV scale, the high
luminosity LHC and tonne-scale may provide complementary
probes.Comment: 5 pages, 3 figure
Hadronic contribution to the muon anomalous magnetic moment to next-to-next-to-leading order
We compute the next-to-next-to-leading order hadronic contribution to the
muon anomalous magnetic moment originating from the photon vacuum polarization.
The corresponding three-loop kernel functions are calculated using asymptotic
expansion techniques which lead to analytic expressions. Our final result,
, has the same order of
magnitude as the current uncertainty of the leading order hadronic contribution
and should thus be included in future analyses.Comment: 9 pages,v2: note on NLO hadronic light-by-light contribution added,
matches published version, Physics Letters B 734 (2014) 144-14
A phosphorylcholine-containing glycolipid-like antigen present on the surface of infective stage larvae of Ascaris spp. is a major antibody target in infected pigs and humans
BACKGROUND: The pig parasite Ascaris suum plays and important role in veterinary medicine and represents a suitable model for A. lumbricoides, which infects over 800 million people. In pigs, continued exposure to Ascaris induces immunity at the level of the gut, protecting the host against migrating larvae. The objective of this study was to identify and characterize parasite antigens targeted by this local immune response that may be crucial for parasite invasion and establishment and to evaluate their protective and diagnostic potential.
METHODOLOGY/PRINCIPAL FINDINGS: Pigs were immunized by trickle infection for 30 weeks, challenged with 2,000 eggs at week 32 and euthanized two weeks after challenge. At necropsy, there was a 100% reduction in worms recovered from the intestine and a 97.2% reduction in liver white spots in comparison with challenged non-immune control animals. Antibodies purified from the intestinal mucus or from the supernatant of cultured antibody secreting cells from mesenteric lymph nodes of immune pigs were used to probe L3 extracts to identify antibody targets. This resulted in the recognition of a 12kDa antigen (As12) that is actively shed from infective Ascaris L3. As12 was characterized as a phosphorylcholine-containing glycolipid-like antigen that is highly resistant to different enzymatic and chemical treatments. Vaccinating pigs with an As12 fraction did not induce protective immunity to challenge infection. However, serological analysis using sera or plasma from experimentally infected pigs or naturally infected humans demonstrated that the As12 ELISA was able to detect long-term exposure to Ascaris with a high diagnostic sensitivity (98.4% and 92%, respectively) and specificity (95.5% and 90.0%) in pigs and humans, respectively.
CONCLUSIONS/SIGNIFICANCE: These findings show the presence of a highly stage specific, glycolipid-like component (As12) that is actively secreted by infectious Ascaris larvae and which acts as a major antibody target in infected humans and pigs
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Why do the maximum intensities in modeled tropical cyclones vary under the same environmental conditions?
In this study w e explored why the different initial tropical cyclone structures can result in different steady‐state maximum intensities in model simulations with the same environmental conditions. We discovered a linear relationsh ip between the radius of maximum wind (rm) and the absolute angular momentum that passes through rm (Mm) in the model simulated steady‐state tropical cyclones that rm = aMm+b. This nonnegligible intercept b is found to be the key to making a steady‐state storm with a larger Mm more intense. The sensitivity experiments show that this nonzero b results mainly from horizontal turbulent mixing and decreases with decreased horizontal mixing. Using this linear relationship from the simulations, it is also found that the degree of supergradient wind is a function of Mm as well as the turbulent mixing length such that both a larger Mm and/or a reduced turbulent mixing length result in larger supergradient winds
Transcriptomic analysis of Ascaris suum larvae during their hepatopulmonary migration
Common roundworms are important intestinal nematodes of man (Ascaris lumbricoides) and pig (Ascaris suum). During the first stages of the infection, the larvae of these parasites undergo a hepatopulmonary migration. This migration is likely to require tightly regulated transcriptional changes in the parasite. We explored this aspect in Ascaris suum by characterizing the transcription profiles of infective L3s from eggs, liver- and lung-L3s and intestinal L4s by next generation sequencing approach. When the most abundant transcripts per life stage were investigated, results showed that in the egg-L3s, transcripts associated with the regulation of translation and transcription, mainly ribosomal proteins, were most abundant. From the liver-L3s onwards, high transcription levels were seen for cuticle collagens, indicating the growth of the larvae during their migration. Interestingly, the type of highly expressed cuticle collagens in the intestinal L4s differed with those present in the liver- and lung-L3s. Apart from collagens, potentially important molecules for host-parasite interaction like C-type lectin-4 and Mucin-5 were in the top 5 of most abundant transcripts in the lung-L3. Unfortunately, a great number of transcripts that are specific for certain larval stages did not show any homology to other proteins within the NCBI database, suggesting that many biologically interesting molecules from this parasite are still to be investigated
The Emission Structure of Formaldehyde MegaMasers
The formaldehyde MegaMaser emission has been mapped for the three host
galaxies IC\,860. IRAS\,151070724, and Arp\,220. Elongated emission
components are found at the nuclear centres of all galaxies with an extent
ranging between 30 to 100 pc. These components are superposed on the peaks of
the nuclear continuum. Additional isolated emission components are found
superposed in the outskirts of the radio continuum structure. The brightness
temperatures of the detected features ranges from 0.6 to 13.4
K, which confirms their masering nature. The masering scenario is interpreted
as amplification of the radio continuum by foreground molecular gas that is
pumped by far-infrared radiation fields in these starburst environments of the
host galaxies.Comment: Accepted MNRA
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