2,582 research outputs found
Characterizing emotion regulation deficits in psychiatric disorders using psychophysiological, neurobiological, and genetic methods
Signal and noise of Diamond Pixel Detectors at High Radiation Fluences
CVD diamond is an attractive material option for LHC vertex detectors because
of its strong radiation-hardness causal to its large band gap and strong
lattice. In particular, pixel detectors operating close to the interaction
point profit from tiny leakage currents and small pixel capacitances of diamond
resulting in low noise figures when compared to silicon. On the other hand, the
charge signal from traversing high energy particles is smaller in diamond than
in silicon by a factor of about 2.2. Therefore, a quantitative determination of
the signal-to-noise ratio (S/N) of diamond in comparison with silicon at
fluences in excess of 10 n cm, which are expected for the
LHC upgrade, is important. Based on measurements of irradiated diamond sensors
and the FE-I4 pixel readout chip design, we determine the signal and the noise
of diamond pixel detectors irradiated with high particle fluences. To
characterize the effect of the radiation damage on the materials and the signal
decrease, the change of the mean free path of the charge
carriers is determined as a function of irradiation fluence. We make use of the
FE-I4 pixel chip developed for ATLAS upgrades to realistically estimate the
expected noise figures: the expected leakage current at a given fluence is
taken from calibrated calculations and the pixel capacitance is measured using
a purposely developed chip (PixCap). We compare the resulting S/N figures with
those for planar silicon pixel detectors using published charge loss
measurements and the same extrapolation methods as for diamond. It is shown
that the expected S/N of a diamond pixel detector with pixel pitches typical
for LHC, exceeds that of planar silicon pixels at fluences beyond 10
particles cm, the exact value only depending on the maximum operation
voltage assumed for irradiated silicon pixel detectors
Gender is more important than advancing age as a predictor of preserved systolic function in older persons hospitalized with heart failure
From Nonspecific DNA–Protein Encounter Complexes to the Prediction of DNA–Protein Interactions
©2009 Gao, Skolnick. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.doi:10.1371/journal.pcbi.1000341DNA–protein interactions are involved in many essential biological activities. Because there is no simple mapping code between DNA base pairs and protein amino acids, the prediction of DNA–protein interactions is a challenging problem. Here, we present a novel computational approach for predicting DNA-binding protein residues and DNA–protein interaction modes without knowing its specific DNA target sequence. Given the structure of a DNA-binding protein, the method first generates an ensemble of complex structures obtained by rigid-body docking with a nonspecific canonical B-DNA. Representative models are subsequently selected through clustering and ranking by their DNA–protein interfacial energy. Analysis of these encounter complex models suggests that the recognition sites for specific DNA binding are usually favorable interaction sites for the nonspecific DNA probe and that nonspecific DNA–protein interaction modes exhibit some similarity to specific DNA–protein binding modes. Although the method requires as input the knowledge that the protein binds DNA, in benchmark tests, it achieves better performance in identifying DNA-binding sites than three previously established methods, which are based on sophisticated machine-learning techniques. We further apply our method to protein structures predicted through modeling and demonstrate that our method performs satisfactorily on protein models whose root-mean-square Ca deviation from native is up to 5 Å from their native structures. This study provides valuable structural insights into how a specific DNA-binding protein interacts with a nonspecific DNA sequence. The similarity between the specific DNA–protein interaction mode and nonspecific interaction modes may reflect an important sampling step in search of its specific DNA targets by a DNA-binding protein
RBS, PIXE, Ion-Microbeam and SR-FTIR Analyses of Pottery Fragments from Azerbaijan
The present work is aimed at the investigation of the ceramic bulk and pigmented glazed surfaces of ancient potteries dating back to XIX century A.D. and coming from the charming archeological site located in the Medieval Agsu town (Azerbaijan), a geographic area of special interest due to the ancient commercial routes between China, Asia Minor, and Europe. For the purpose of the study, complementary investigation tools have been exploited: non-destructive or micro-destructive investigation at elemental level by ion beam analysis (IBA) techniques, by using Rutherford Backscattering Spectrometry (RBS), Proton-Induced X-ray Emission (PIXE) spectroscopy and ion-microbeam analysis, and chemical characterization at microscopic level, by means of synchrotron radiation (SR) Fourier transform infrared (FTIR) microspectroscopy. The acquired information reveals useful for the identification of the provenance, the reconstruction of the firing technology, and finally, the identification of the pigment was used as a colorant of the glaze
Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter
We present a study of showers initiated by electrons, pions, kaons, and
protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE
scintillator-tungsten analogue hadronic calorimeter. The data were recorded at
the CERN Super Proton Synchrotron in 2011. The analysis includes measurements
of the calorimeter response to each particle type as well as measurements of
the energy resolution and studies of the longitudinal and radial shower
development for selected particles. The results are compared to Geant4
simulations (version 9.6.p02). In the study of the energy resolution we include
previously published data with beam momenta from 1 GeV to 10 GeV recorded at
the CERN Proton Synchrotron in 2010.Comment: 35 pages, 21 figures, 8 table
Pion and proton showers in the CALICE scintillator-steel analogue hadron calorimeter
Showers produced by positive hadrons in the highly granular CALICE
scintillator-steel analogue hadron calorimeter were studied. The experimental
data were collected at CERN and FNAL for single particles with initial momenta
from 10 to 80 GeV/c. The calorimeter response and resolution and spatial
characteristics of shower development for proton- and pion-induced showers for
test beam data and simulations using Geant4 version 9.6 are compared.Comment: 26 pages, 16 figures, JINST style, changes in the author list, typos
corrected, new section added, figures regrouped. Accepted for publication in
JINS
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