472 research outputs found
Matter effects in the D0-D0bar system
We discuss the impact of matter effects in the D0-D0bar system. We show that
such effects could, in principle, be measured, but that they cannot be used to
probe the mass difference x_D or the lifetime difference y_D. This occurs
because the mixing effects and the matter effects decouple at short times. We
also comment briefly on the B systems.Comment: 6 pages, RevTe
Optimal entanglement witnesses for continuous-variable systems
This paper is concerned with all tests for continuous-variable entanglement
that arise from linear combinations of second moments or variances of canonical
coordinates, as they are commonly used in experiments to detect entanglement.
All such tests for bi-partite and multi-partite entanglement correspond to
hyperplanes in the set of second moments. It is shown that all optimal tests,
those that are most robust against imperfections with respect to some figure of
merit for a given state, can be constructed from solutions to semi-definite
optimization problems. Moreover, we show that for each such test, referred to
as entanglement witness based on second moments, there is a one-to-one
correspondence between the witness and a stronger product criterion, which
amounts to a non-linear witness, based on the same measurements. This
generalizes the known product criteria. The presented tests are all applicable
also to non-Gaussian states. To provide a service to the community, we present
the documentation of two numerical routines, FULLYWIT and MULTIWIT, which have
been made publicly available.Comment: 14 pages LaTeX, 1 figure, presentation improved, references update
Cell-cell adhesion regulates Merlin/NF2 interaction with the PAF complex
The PAF complex (PAFC) coordinates transcription elongation and mRNA processing and its CDC73/parafibromin subunit functions as a tumour suppressor. The NF2/Merlin tumour suppressor functions both at the cell cortex and nucleus and is a key mediator of contact inhibition but the molecular mechanisms remain unclear. In this study we have used affinity proteomics to identify novel Merlin interacting proteins and show that Merlin forms a complex with multiple proteins involved in RNA processing including the PAFC and the CHD1 chromatin remodeller. Tumour-derived inactivating mutations in both Merlin and the CDC73 PAFC subunit mutually disrupt their interaction and growth suppression by Merlin requires CDC73. Merlin interacts with the PAFC in a cell density-dependent manner and we identify a role for FAT cadherins in regulating the Merlin-PAFC interaction. Our results suggest that in addition to its function within the Hippo pathway, Merlin is part of a tumour suppressor network regulated by cell-cell adhesion which coordinates post-initiation steps of the transcription cycle of genes mediating contact inhibition
The First Human Epitope Map of the Alphaviral E1 and E2 Proteins Reveals a New E2 Epitope with Significant Virus Neutralizing Activity
Although the murine immune response to Venezuelan equine encephalitis virus (VEEV) is well-characterized, little is known about the human antibody response to VEEV. In this study we used phage display technology to isolate a panel of 11 VEEV-specfic Fabs from two human donors. Seven E2-specific and four E1-specific Fabs were identified and mapped to five E2 epitopes and three E1 epitopes. Two neutralizing Fabs were isolated, E2-specific F5 and E1-specific L1A7, although the neutralizing capacity of L1A7 was 300-fold lower than F5. F5 Fab was expressed as a complete IgG1 molecule, F5 native (n) IgG. Neutralization-escape VEEV variants for F5 nIgG were isolated and their structural genes were sequenced to determine the theoretical binding site of F5. Based on this sequence analysis as well as the ability of F5 to neutralize four neutralization-escape variants of anti-VEEV murine monoclonal antibodies (mapped to E2 amino acids 182–207), a unique neutralization domain on E2 was identified and mapped to E2 amino acids 115–119
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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Dominant role of greenhouse-gas forcing in the recovery of Sahel rainfall
Sahelian summer rainfall, controlled by the West African
monsoon, exhibited large-amplitude multidecadal variability
during the twentieth century. Particularly important was the
severe drought of the 1970s and 1980s, which had widespread
impacts1–6. Research into the causes of this drought has
identified anthropogenic aerosol forcing3,4,7 and changes in
sea surface temperatures (SSTs; refs 1,2,6,8–11) as the most
important drivers. Since the 1980s, there has been some
recovery of Sahel rainfall amounts2–6,11–14, although not to
the pre-drought levels of the 1940s and 1950s. Here we
report on experiments with the atmospheric component of a
state-of-the-art global climate model to identify the causes
of this recovery. Our results suggest that the direct influence
of higher levels of greenhouse gases in the atmosphere
was the main cause, with an additional role for changes
in anthropogenic aerosol precursor emissions. We find that
recent changes in SSTs, although substantial, did not have a
significant impact on the recovery. The simulated response
to anthropogenic greenhouse-gas and aerosol forcing is
consistent with a multivariate fingerprint of the observed
recovery, raising confidence in our findings. Although robust
predictions are not yet possible, our results suggest that the
recent recovery in Sahel rainfall amounts is most likely to be
sustained or amplified in the near term
Evaluation of Chikungunya Diagnostic Assays: Differences in Sensitivity of Serology Assays in Two Independent Outbreaks
Chikungunya is a mounting public health concern in many parts of the world. Definitive diagnosis is critical in differentiating the diseases, especially in dengue endemic areas. There are some commercial chikungunya kits and published molecular protocols available, but no comprehensive comparative evaluation of them was performed. Using sera collected in outbreaks caused by two variants of Chikungunya virus (A226 and 226V), we tested 2 commercial IgM tests (CTK lateral flow rapid test and EUROIMMUN IFA) alongside our in-house IgM assays (using both variants of the virus). Sensitivities of 2 published PCR protocols were also evaluated based on RNA standards derived from cell-cultured viruses. The commercial assays had different performances in each outbreak, with CTK's lateral flow test having the best performance in the first outbreak and EUROIMMUN IFA being more sensitive in the second outbreak. Use of the current circulating virus in a test assay improves sensitivity of the MAC-ELISAs. For PCR, a probe-based real time RT-PCR method was found to be 10 times more sensitive than the SYBR Green method. Despite this, the latter protocol is found to be more suitable and cost-effective for our diagnostic laboratory. This evaluation demonstrates the importance of appraisal of commercial kits and published protocols before application of a diagnostic tool in the clinical and operational setting
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Identification of Continuous Human B-Cell Epitopes in the Envelope Glycoprotein of Dengue Virus Type 3 (DENV-3)
BACKGROUND:Dengue virus infection is a growing global public health concern in tropical and subtropical regions of the world. Dengue vaccine development has been hampered by concerns that cross-reactive immunological memory elicited by a candidate vaccine could increase the risk of development of more severe clinical forms. One possible strategy to reduce risks associated with a dengue vaccine is the development of a vaccine composed of selected critical epitopes of each of the serotypes. METHODOLOGY/PRINCIPAL FINDINGS:Synthetic peptides were used to identify B-cell epitopes in the envelope (E) glycoprotein of dengue virus type 3 (DENV-3). Eleven linear, immunodominant epitopes distributed in five regions at amino acid (aa) positions: 51-65, 71-90, 131-170, 196-210 and 246-260 were identified by employing an enzyme- linked immunosorbent assay (ELISA), using a pool of human sera from dengue type 3 infected individuals. Peptides 11 (aa51-65), 27 and 28 (aa131-150) also reacted with dengue 1 (DENV-1) and dengue 2 (DENV-2) patient sera as analyzed through the ROC curves generated for each peptide by ELISA and might have serotype specific diagnostic potential. Mice immunized against each one of the five immunogenic regions showed epitopes 51-65, 131-170, 196-210 and 246-260 elicited the highest antibody response and epitopes131-170, 196-210 and 246-260, elicited IFN-gamma production and T CD4+ cell response, as evaluated by ELISA and ELISPOT assays respectively. CONCLUSIONS/SIGNIFICANCE:Our study identified several useful immunodominant IgG-specific epitopes on the envelope of DENV-3. They are important tools for understanding the mechanisms involved in antibody dependent enhancement and immunity. If proven protective and safe, in conjunction with others well-documented epitopes, they might be included into a candidate epitope-based vaccine
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