646 research outputs found
ATLAS Monitored Drift Tube Chambers in E = 11 MeV Neutron Background
The influence of fast neutrons on the occupancy and the single tube
resolution of ATLAS muon drift detectors was investigated by exposing a chamber
built out of 3 layers of 3 short standard drift tubes to neutron flux-densities
of up to 16 kHz/cm2 at a neutron energy of E=11 MeV. Pulse shape capable NE213
scintillaton detectors and a calibrated BF3 neutron detector provided
monitoring of the neutron flux-density and energy. The sensitivity of the drift
chamber to the neutrons was measured to be 4*10-4 by comparing data sets with
and without neutron background. For the investigation of tracks of cosmic muons
two silicon-strip detectors above and underneath the chamber allow to compare
measured drift-radii with reference tracks. Alternatively, the single tube
resolution was determined using the triple-sum method. The comparison between
data with and without neutron irradiation shows only a marginal effect on the
resolution and little influence on the muon track reconstruction.Comment: 4 pages, 11 figures, conferenc
Temperature Studies for ATLAS MDT BOS Chambers
Data sets with high statistics taken at the cosmic ray facility, equipped
with 3 ATLAS BOS MDT chambers, in Garching (Munich) have been used to study
temperature and pressure effects on gas gain and drifttime. The deformation of
a thermally expanded chamber was reconstructed using the internal RasNik
alignment monitoring system and the tracks from cosmic data. For these studies
a heating system was designed to increase the temperature of the middle chamber
by up to 20 Kelvins over room temperature. For comparison the temperature
effects on gas properties have been simulated with Garfield. The maximum
drifttime decreased under temperature raise by -2.21 +- 0.08 ns/K, in agreement
with the results of pressure variations and the Garfield simulation. The
increased temperatures led to a linear increase of the gas gain of about 2.1%
1/K. The chamber deformation has been analyzed with the help of reconstructed
tracks. By the comparison of the tracks through the reference chambers with
these through the test chamber the thermal expansion has been reconstructed and
the result shows agreement with the theoretical expansion coefficient. As the
wires are fixed at the end of the chamber, the wire position calculation can
not provide a conclusion for the chamber middle. The complete deformation has
been identified with the analysis of the monitoring system RasNik, whose
measured values have shown a homogeneous expansion of the whole chamber,
overlayed by a shift and a rotation of the chamber middle with respect to the
outer part of the chamber. The established results of both methods are in
agreement. We present as well a model for the position-drifttime correction as
function of temperature.Comment: 4 pages, 12 figures, conferenc
An investigation of the impact of data breach severity on the readability of mandatory data breach notification letters: evidence from U.S. firms
The aim of this article is to investigate the impact of data breach severity on the readability of mandatory data breach notification letters. Using a content analysis approach to determine data breach severity attributes (measured by the total number of breached records, type of data accessed, the source of the data breach, and how the data were used), in conjunction with readability measures (reading complexity, numerical intensity, length of letter, word size, and unique words), 512 data breach incidents from 281 U.S. firms across the 2012â2015 period were examined.
The results indicate that data breach severity has a positive impact on reading complexity, length of letter, word size, and unique words, and a negative impact on numerical terms. Interpreting the results collectively through the lens of impression management, it can be inferred that business managers may be attempting to obfuscate bad news associated with high data breach severity incidents by manipulating syntactical features of the data breach notification letters in a way that makes the message difficult for individuals to comprehend.
The study contributes to the information studies and impression management behavior literatures by analyzing linguistic cues in notifications following a data breach incident
Spatially resolved spectroscopy of Coma cluster early-type galaxies - II:the minor axis dataset
We present minor axis, off set major axis and one diagonal long slit spectra for 10 E and S0 galaxies of the Coma cluster drawn from a magnitude-limited sample studied before. We derive rotation curves, velocity dispersion profiles and the H-3 and H-4 coefficients of the Hermite decomposition of the line of sight velocity distribution. Moreover, we derive the line index profiles of Mg, Fe and Hbeta line indices and assess their errors. The data will be used to construct dynamical models of the galaxies and study their stellar populations
Random walks in random Dirichlet environment are transient in dimension
We consider random walks in random Dirichlet environment (RWDE) which is a
special type of random walks in random environment where the exit probabilities
at each site are i.i.d. Dirichlet random variables. On , RWDE are
parameterized by a -uplet of positive reals. We prove that for all values
of the parameters, RWDE are transient in dimension . We also prove that
the Green function has some finite moments and we characterize the finite
moments. Our result is more general and applies for example to finitely
generated symmetric transient Cayley graphs. In terms of reinforced random
walks it implies that directed edge reinforced random walks are transient for
.Comment: New version published at PTRF with an analytic proof of lemma
Role of Sb in the superconducting kagome metal CsV$3Sb5 revealed by its anisotropic compression
Pressure evolution of the superconducting kagome metal CsVSb is
studied with single-crystal x-ray diffraction and density-functional
band-structure calculations. A highly anisotropic compression observed up to 5
GPa is ascribed to the fast shrinkage of the Cs-Sb distances and suppression of
Cs rattling motion. This prevents Sb displacements required to stabilize the
three-dimensional charge-density-wave (CDW) order and elucidates the
disappearance of the CDW already at 2 GPa despite only minor changes in the
electronic structure of the normal state. At higher pressures, vanadium bands
still change only marginally, whereas antimony bands undergo a major
reconstruction caused by the gradual formation of the interlayer Sb-Sb bonds.
Our results exclude pressure tuning of vanadium kagome bands as the main
mechanism for the non-trivial evolution of superconductivity in real-world
kagome metals. Concurrently, we establish the central role of Sb atoms in the
stabilization of a three-dimensional CDW and Fermi surface reconstruction.Comment: published versio
Chiral confinement in quasirelativistic Bose-Einstein condensates
In the presence of a laser-induced spin-orbit coupling an interacting ultra
cold spinor Bose-Einstein condensate may acquire a quasi-relativistic character
described by a non-linear Dirac-like equation. We show that as a result of the
spin-orbit coupling and the non-linearity the condensate may become
self-trapped, resembling the so-called chiral confinement, previously studied
in the context of the massive Thirring model. We first consider 1D geometries
where the self-confined condensates present an intriguing sinusoidal dependence
on the inter-particle interactions. We further show that multi-dimensional
chiral-confinement is also possible under appropriate feasible laser
arrangements, and discuss the properties of 2D and 3D condensates, which differ
significantly from the 1D case.Comment: 4 page
Impression management and retrospective sense-making in corporate annual reports: banks' graphical reporting during the global financial crisis
This study investigates two potentially complementary reporting scenarios in annual reports: reactive impression management and retrospective sense-making. It examines stock market performance graphs in European listed banks? annual reports before and during the global financial crisis. Our results indicate that banks reacted to the global financial crisis by omitting stock market performance graphs from the annual report and from its most prominent sections. On the other hand, banks reduced favorable distortions and favorable performance comparisons. No significant evidence of retrospective sense-making is found. Overall, the findings are consistent with impression management incorporating human cognitive biases, with companies preferring misrepresentation by omission over misrepresentation by commission. Under high public scrutiny, banks appear to seek to provide a more favorable view by concealing negative information rather than by favorable distortions or comparisons. The study contributes to the development of impression management theories. It uses a psychological interpretation that incorporates human cognitive biases, rather than adopting a purely economically based perspective
Gene silencing pathways found in the green alga Volvox carteri reveal insights into evolution and origins of small RNA systems in plants
Background: Volvox carteri (V. carteri) is a multicellular green alga used as model system for the evolution of multicellularity. So far, the contribution of small RNA pathways to these phenomena is not understood. Thus, we have sequenced V. carteri Argonaute 3 (VcAGO3)-associated small RNAs from different developmental stages. Results: Using this functional approach, we define the Volvox microRNA (miRNA) repertoire and show that miRNAs are not conserved in the closely related unicellular alga Chlamydomonas reinhardtii. Furthermore, we find that miRNAs are differentially expressed during different life stages of V. carteri. In addition to miRNAs, transposon-associated small RNAs or phased siRNA loci, which are common in higher land plants, are highly abundant in Volvox as well. Transposons not only give rise to miRNAs and other small RNAs, they are also targets of small RNAs. Conclusion: Our analyses reveal a surprisingly complex small RNA network in Volvox as elaborate as in higher land plants. At least the identified VcAGO3-associated miRNAs are not conserved in C. reinhardtii suggesting fast evolution of small RNA systems. Thus, distinct small RNAs may contribute to multicellularity and also division of labor in reproductive and somatic cells
Genes optimized by evolution for accurate and fast translation encode in Archaea and Bacteria a broad and characteristic spectrum of protein functions
BACKGROUND: In many microbial genomes, a strong preference for a small number of codons can be observed in genes whose products are needed by the cell in large quantities. This codon usage bias (CUB) improves translational accuracy and speed and is one of several factors optimizing cell growth. Whereas CUB and the overrepresentation of individual proteins have been studied in detail, it is still unclear which high-level metabolic categories are subject to translational optimization in different habitats. RESULTS: In a systematic study of 388 microbial species, we have identified for each genome a specific subset of genes characterized by a marked CUB, which we named the effectome. As expected, gene products related to protein synthesis are abundant in both archaeal and bacterial effectomes. In addition, enzymes contributing to energy production and gene products involved in protein folding and stabilization are overrepresented. The comparison of genomes from eleven habitats shows that the environment has only a minor effect on the composition of the effectomes. As a paradigmatic example, we detailed the effectome content of 37 bacterial genomes that are most likely exposed to strongest selective pressure towards translational optimization. These effectomes accommodate a broad range of protein functions like enzymes related to glycolysis/gluconeogenesis and the TCA cycle, ATP synthases, aminoacyl-tRNA synthetases, chaperones, proteases that degrade misfolded proteins, protectants against oxidative damage, as well as cold shock and outer membrane proteins. CONCLUSIONS: We made clear that effectomes consist of specific subsets of the proteome being involved in several cellular functions. As expected, some functions are related to cell growth and affect speed and quality of protein synthesis. Additionally, the effectomes contain enzymes of central metabolic pathways and cellular functions sustaining microbial life under stress situations. These findings indicate that cell growth is an important but not the only factor modulating translational accuracy and speed by means of CUB
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