3,082 research outputs found
CD44+ cancer stem-like cells in EBV-associated nasopharyngeal carcinoma.
published_or_final_versio
HPV infection and immunochemical detection of cell-cycle markers in verrucous carcinoma of the penis
Penile verrucous carcinoma is a rare disease and little is known of its aetiology or pathogenesis. In this study we examined cell-cycle proteins expression and correlation with human papillomavirus infection in a series of 15 pure penile verrucous carcinomas from a single centre. Of 148 penile tumours, 15 (10%) were diagnosed as pure verrucous carcinomas. The expression of the cell-cycle-associated proteins p53, p21, RB, p16INK4A and Ki67 were examined by immunohistochemistry. Human papillomavirus infection was determined by polymerase chain reaction to identify a wide range of virus types. The expression of p16INK4A and Ki67 was significantly lower in verrucous carcinoma than in usual type squamous cell carcinoma, whereas the expression of p53, p21 and RB was not significantly different. p53 showed basal expression in contrast to usual type squamous cell carcinoma. Human papillomavirus infection was present in only 3 out of 13 verrucous carcinomas. Unique low-risk, high-risk and mixed viral infections were observed in each of the three cases. In conclusion, lower levels of p16INK4A and Ki67 expressions differentiate penile verrucous carcinoma from usual type squamous cell carcinoma. The low Ki67 index reflects the slow-growing nature of verrucous tumours. The low level of p16INK4A expression and human papillomavirus detection suggests that penile verrucous carcinoma pathogenesis is unrelated to human papillomavirus infection and the oncogenes and tumour suppressor genes classically altered by virus infection.Peer reviewedFinal Accepted Versio
Entangled-State Cycles of Atomic Collective-Spin States
We study quantum trajectories of collective atomic spin states of
effective two-level atoms driven with laser and cavity fields. We show that
interesting ``entangled-state cycles'' arise probabilistically when the (Raman)
transition rates between the two atomic levels are set equal. For odd (even)
, there are () possible cycles. During each cycle the
-qubit state switches, with each cavity photon emission, between the states
, where is a Dicke state in a rotated
collective basis. The quantum number (), which distinguishes the
particular cycle, is determined by the photon counting record and varies
randomly from one trajectory to the next. For even it is also possible,
under the same conditions, to prepare probabilistically (but in steady state)
the Dicke state , i.e., an -qubit state with excitations,
which is of particular interest in the context of multipartite entanglement.Comment: 10 pages, 9 figure
Fermi Gamma-ray Imaging of a Radio Galaxy
The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating
from the giant radio lobes of the radio galaxy Centaurus A. The resolved
gamma-ray image shows the lobes clearly separated from the central active
source. In contrast to all other active galaxies detected so far in high-energy
gamma-rays, the lobe flux constitutes a considerable portion (>1/2) of the
total source emission. The gamma-ray emission from the lobes is interpreted as
inverse Compton scattered relic radiation from the cosmic microwave background
(CMB), with additional contribution at higher energies from the
infrared-to-optical extragalactic background light (EBL). These measurements
provide gamma-ray constraints on the magnetic field and particle energy content
in radio galaxy lobes, and a promising method to probe the cosmic relic photon
fields.Comment: 27 pages, includes Supplementary Online Material; corresponding
authors: C.C. Cheung, Y. Fukazawa, J. Knodlseder, L. Stawar
Detection of Gamma-Ray Emission from the Starburst Galaxies M82 and NGC 253 with the Large Area Telescope on Fermi
We report the detection of high-energy gamma-ray emission from two starburst
galaxies using data obtained with the Large Area Telescope on board the Fermi
Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been
detected at significance levels of 6.8 sigma and 4.8 sigma respectively, from
sources positionally coincident with locations of the starburst galaxies M82
and NGC 253. The total fluxes of the sources are consistent with gamma-ray
emission originating from the interaction of cosmic rays with local
interstellar gas and radiation fields and constitute evidence for a link
between massive star formation and gamma-ray emission in star-forming galaxies.Comment: Submitted to ApJ Letter
The Interplay Between GUT and Flavour Symmetries in a Pati-Salam x S4 Model
Both Grand Unified symmetries and discrete flavour symmetries are appealing
ways to describe apparent structures in the gauge and flavour sectors of the
Standard Model. Both symmetries put constraints on the high energy behaviour of
the theory. This can give rise to unexpected interplay when building models
that possess both symmetries. We investigate on the possibility to combine a
Pati-Salam model with the discrete flavour symmetry that gives rise to
quark-lepton complementarity. Under appropriate assumptions at the GUT scale,
the model reproduces fermion masses and mixings both in the quark and in the
lepton sectors. We show that in particular the Higgs sector and the running
Yukawa couplings are strongly affected by the combined constraints of the Grand
Unified and family symmetries. This in turn reduces the phenomenologically
viable parameter space, with high energy mass scales confined to a small region
and some parameters in the neutrino sector slightly unnatural. In the allowed
regions, we can reproduce the quark masses and the CKM matrix. In the lepton
sector, we reproduce the charged lepton masses, including bottom-tau
unification and the Georgi-Jarlskog relation as well as the two known angles of
the PMNS matrix. The neutrino mass spectrum can present a normal or an inverse
hierarchy, and only allowing the neutrino parameters to spread into a range of
values between and , with .
Finally, our model suggests that the reactor mixing angle is close to its
current experimental bound.Comment: 62 pages, 4 figures; references added, version accepted for
publication in JHE
Participant recruitment into a randomised controlled trial of exercise therapy for people with multiple sclerosis
The success of a clinical trial is often dependant on whether recruitment targets can be met in the required time frame. Despite an increase in research into the benefits of exercise in people with multiple sclerosis (PwMS), no trial has reported detailed data on effective recruitment strategies for large-scale randomised controlled trials. The main purpose of this report is to provide a detailed outline of recruitment strategies, rates and estimated costs in the Exercise Intervention for Multiple Sclerosis (ExIMS) trial to identify best practices for future trials involving multiple sclerosis (MS) patient recruitment
New Physics in Bs -> J/psi phi: a General Analysis
Recently, the CDF and D0 collaborations measured indirect CP violation in Bs
-> J/psi phi and found a hint of a signal. If taken at face value, this can be
interpreted as a nonzero phase of Bs-Bsbar mixing (beta_s), in disagreement
with the standard model, which predicts that beta_s ~= 0. In this paper, we
argue that this analysis may be incomplete. In particular, there can be new
physics (NP) in the bbar -> sbar c cbar decay. If so, the value of beta_s is
different than for the case in which NP is assumed to be present only in the
mixing. We have examined several models of NP and found that, indeed, there can
be significant contributions to the decay. These effects are consistent with
measurements in B -> J/psi K* and Bd -> J/psi Ks. Due to the NP in the decay,
polarization-dependent indirect CP asymmetries and triple-product asymmetries
are predicted in Bs -> J/psi phi.Comment: 28 pages, JHEP, no figures. Considerable changes made. Abstract and
main text of paper modified to alter presentation. Appendix added. References
added. Conclusions unchanged
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
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
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