1,667 research outputs found
On smoothness of Black Saturns
We prove smoothness of the domain of outer communications (d.o.c.) of the
Black Saturn solutions of Elvang and Figueras. We show that the metric on the
d.o.c. extends smoothly across two disjoint event horizons with topology R x
S^3 and R x S^1 x S^2. We establish stable causality of the d.o.c. when the
Komar angular momentum of the spherical component of the horizon vanishes, and
present numerical evidence for stable causality in general.Comment: 47 pages, 5 figure
Improving ductal carcinoma in situ classification by convolutional neural network with exponential linear unit and rank-based weighted pooling
Ductal carcinoma in situ (DCIS) is a pre-cancerous lesion in the ducts of the breast, and early diagnosis is crucial for optimal
therapeutic intervention. Thermography imaging is a non-invasive imaging tool that can be utilized for detection of DCIS and
although it has high accuracy (~88%), it is sensitivity can still be improved. Hence, we aimed to develop an automated artificial
intelligence-based system for improved detection of DCIS in thermographs. This study proposed a novel artificial intelligence
based system based on convolutional neural network (CNN) termed CNN-BDER on a multisource dataset containing 240
DCIS images and 240 healthy breast images. Based on CNN, batch normalization, dropout, exponential linear unit and
rank-based weighted pooling were integrated, along with L-way data augmentation. Ten runs of tenfold cross validation were
chosen to report the unbiased performances. Our proposed method achieved a sensitivity of 94.08±1.22%, a specificity
of 93.58±1.49 and an accuracy of 93.83±0.96. The proposed method gives superior performance than eight state-of-theart
approaches and manual diagnosis. The trained model could serve as a visual question answering system and improve
diagnostic accuracy.British Heart Foundation Accelerator Award, UKRoyal Society International Exchanges Cost Share Award, UK
RP202G0230Hope Foundation for Cancer Research, UK
RM60G0680Medical Research Council Confidence in Concept Award, UK
MC_PC_17171MINECO/FEDER, Spain/Europe
RTI2018-098913-B100
A-TIC-080-UGR1
Toll-Like Receptor Ligands Induce Human T Cell Activation and Death, a Model for HIV Pathogenesis
Background: Recently, heightened systemic translocation of microbial products was found in persons with chronic HIV infection and this was linked to immune activation and CD4 + T cell homeostasis. Methodology: We examined here the effects of microbial Toll-like receptor (TLR) ligands on T cell activation in vitro. Conclusions/Findings: We show that exposure to TLR ligands results in activation of memory and effector CD4 + and CD8 + T cells. After exposure to each of 8 different ligands that activate TLRs 2, 3, 4, 5, 7, 8, and 9, CD8 + T cells are activated and gain expression of the C type lectin CD69 that may promote their retention in lymphoid tissues. In contrast, CD4 + T cells rarely increase CD69 expression but instead enter cell cycle. Despite activation and cell cycle entry, CD4 + T cells divide poorly and instead, disproportionately undergo activation-induced cell death. Systemic exposure to TLR agonists may therefore increase immune activation, effector cell sequestration in lymphoid tissues and T cell turnover. These events may contribute to the pathogenesis of immune dysfunction and CD4+ T cell losses in chronic infection with the human immunodeficiency virus
A novel mutation of the calcium sensing receptor gene is associated with chronic pancreatitis in a family with heterozygous SPINK1 mutations
BACKGROUND: The role of mutations in the serine protease inhibitor Kazal type 1 (SPINK1) gene in chronic pancreatitis is still a matter of debate. Active SPINK1 is thought to antagonize activated trypsin. Cases of SPINK1 mutations, especially N34S, have been reported in a subset of patients with idiopathic chronic pancreatitis. However, the inheritance pattern is still unknown. Some cases with N34S heterozygosity have been reported with and without evidence for CP indicating neither an autosomal recessive nor dominant trait. Therefore SPINK1 mutations have been postulated to act as a disease modifier requiring additional mutations in a more complex genetic model. Familial hypocalciuric hypercalcemia (FHH) caused by heterozygous inactivating mutations in the calcium sensing receptor (CASR) gene is considered a benign disorder with elevated plasma calcium levels. Although hypercalcemia represents a risk factor for pancreatitis, increased rates of pancreatitis in patients with FHH have not been reported thus far. METHODS: We studied a family with a FHH-related hypercalcemia and chronic pancreatitis. DNA samples were analysed for mutations within the cationic trypsinogen (N29I, R122H) and SPINK1 (N34S) gene using melting curve analysis. Mutations within CASR gene were identified by DNA sequencing. RESULTS: A N34S SPINK1 mutation was found in all screened family members. However, only two family members developed chronic pancreatitis. These patients also had FHH caused by a novel, sporadic mutation in the CASR gene (518T>C) leading to an amino acid exchange (leucine->proline) in the extracellular domain of the CASR protein. CONCLUSION: Mutations in the calcium sensing receptor gene might represent a novel as yet unidentified predisposing factor which may lead to an increased susceptibility for chronic pancreatitis. Moreover, this family analysis supports the hypothesis that SPINK1 mutations act as disease modifier and suggests an even more complex genetic model in SPINK1 related chronic pancreatitis
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy
A search for new physics is performed in events with two same-sign isolated
leptons, hadronic jets, and missing transverse energy in the final state. The
analysis is based on a data sample corresponding to an integrated luminosity of
4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of
7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of
140 increase in integrated luminosity over previously published results. The
observed yields agree with the standard model predictions and thus no evidence
for new physics is found. The observations are used to set upper limits on
possible new physics contributions and to constrain supersymmetric models. To
facilitate the interpretation of the data in a broader range of new physics
scenarios, information on the event selection, detector response, and
efficiencies is provided.Comment: Published in Physical Review Letter
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Precise measurement of the W-boson mass with the CDF II detector
We have measured the W-boson mass MW using data corresponding to 2.2/fb of
integrated luminosity collected in proton-antiproton collisions at 1.96 TeV
with the CDF II detector at the Fermilab Tevatron collider. Samples consisting
of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement
MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most
precise measurement of the W-boson mass to date and significantly exceeds the
precision of all previous measurements combined
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