97 research outputs found
3D Hydrodynamic Simulations of the Galactic Supernova Remnant CTB 109
Using detailed 3D hydrodynamic simulations we study the nature of the
Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0), which is well-known for
its semicircular shape and a bright diffuse X-ray emission feature inside the
SNR. Our model has been designed to explain the observed morphology, with a
special emphasis on the bright emission feature inside the SNR. Moreover, we
determine the age of the remnant and compare our findings with X-ray
observations. With CTB 109 we test a new method of detailed numerical
simulations of diffuse young objects, using realistic initial conditions
derived directly from observations. We performed numerical 3D simulations with
the RAMSES code. The initial density structure has been directly taken from
CO emission data, adding an additional dense cloud, which, when it is
shocked, causes the bright emission feature. From parameter studies we obtained
the position for an elliptical
cloud with based on the preshock density
from Chandra data and a maximum diameter of 4.54 pc, whose encounter with the
supernova (SN) shock wave generates the bright X-ray emission inside the SNR.
The calculated age of the remnant is about 11,000 yr according to our
simulations. In addition, we can also determine the most probable site of the
SN explosion. Hydrodynamic simulations can reproduce the morphology and the
observed size of the SNR CTB 109 remarkably well. Moreover, the simulations
show that it is very plausible that the bright X-ray emission inside the SNR is
the result of an elliptical dense cloud shocked by the SN explosion wave. We
show that numerical simulations using observational data for an initial model
can produce meaningful results.Comment: 9 pages, 6 figures, accepted for publication in A&
Tetrabutylammonium tris(methylsulfanylmethyl)phenylborate
In the title molecular salt, C16H36N+·C12H20BS3-, three of the four n-butyl chains show a trans conformation, whereas the fourth has the C—C—C—C torsion angle in a gauche conformation [-77.8 (5)°]. In the crystal, molecules are packed in layers parallel to the (101) plane
9,9-Dimethyl-9-silafluorene
The title compound, C14H14Si, crystallizes with two almost identical molecules (r.m.s. deviation = 0.080 Å for all non-H atoms) in the asymmetric unit. All atoms of the silafluorene moiety lie in a common plane (r.m.s. deviations = 0.049 and 0.035 Å for the two molecules in the asymmetric unit). The Si—Cmethyl bonds are significantly shorter [1.865 (4)–1.868 (4) Å] than the Si—Caromatic bonds [1.882 (3)–1.892 (3) Å]. Owing to strain in the five-membered ring, the endocyclic C—Si—C angles are reduced to 91.05 (14) and 91.21 (14)°
Biphenyl-4,4′-diyl bis(2,2,5,5-tetramethyl-1-oxyl-3-pyrroline-3-carboxylate)
In the title compound, C30H34N2O6, the complete molecule is generated by a crystallographic 2/m symmetry operation. The 1-oxyl-3-pyrroline-3-carboxylate group lies on a mirror plane. The dihedral angle between the ring planes of the biphenyl fragment is constrained by symmetry to be zero, resulting in rather short intramolecular H⋯H contact distances of 2.02 Å. In the crystal, molecules are connected along the a-axis direction by very weak intermolecular methyl–phenyl C—H⋯π interactions. The C—H bond is not directed to the center of the benzene ring, but mainly to one C atom [C—H⋯C(x − 1, y, z): H⋯C = 2.91 Å and C—H⋯C = 143°]
3D Line Radiative Transfer & Synthetic Observations with Magritte
Electromagnetic radiation is a key component in many astrophysical simulations. Not only does
it dictate what we can or cannot observe, it can provide radiation pressure, efficient heating and
cooling mechanisms, and opens up a range of new chemical pathways due to photo-reactions.
Magritte is a software library that can be used as a general-purpose radiative transfer solver,
but was particularly designed for line radiative transfer in complex 3D morphologies, such
as, for instance, encountered in the stellar winds around evolved stars (see Decin, 2020). It
is mainly written in C++ and can either be used as a Python package or as a C++ library.
To compute the radiation field, a deterministic ray-tracer and a formal solver are employed,
i.e., rays are traced through the model and the radiative transfer equation is solved along
those rays (De Ceuster et al., 2019). This is in contrast to most radiative transfer solvers
which employ (probabilistic) Monte Carlo techniques (Noebauer & Sim, 2019). By virtue
of minimal assumptions about the underlying geometric structure of a model, Magritte can
handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics
(SPH) data. Furthermore, tools are provided to optimise different input meshes for radiative
transfer (De Ceuster et al., 2020)
Relation Between Oceanic Plate Structure, Patterns of Interplate Locking and Microseismicity in the 1922 Atacama Seismic Gap
We deployed a dense geodetic and seismological network in the Atacama seismic gap in Chile. We derive a microseismicity catalog of >30,000 events, time series from 70 GNSS stations, and utilize a transdimensional Bayesian inversion to estimate interplate locking. We identify two highly locked regions of different sizes whose geometries appear to control seismicity patterns. Interface seismicity concentrates beneath the coastline, just downdip of the highest locking. A region with lower locking (27.5°S–27.7°S) coincides with higher seismicity levels, a high number of repeating earthquakes and events extending toward the trench. This area is situated where the Copiapó Ridge is subducted and has shown previous indications of both seismic and aseismic slip, including an earthquake sequence in 2020. While these findings suggest that the structure of the downgoing oceanic plate prescribes patterns of interplate locking and seismicity, we note that the Taltal Ridge further north lacks a similar signature
Роль страдающей депрессией матери в развитии личности ребенка
С позиций психодинамического подхода показана роль страдающей депрессией матери в формировании личности ребенка на первых этапах его постнатального развития и ее влияние на его психическое здоровье в дальнейшем.The role of the mother with depression in development of the child's personality at the first stages of the postnatal period as well as its influence on his/her mental state in future are shown from the perspective of a psychodynamic approach
Determining Supersymmetric Parameters With Dark Matter Experiments
In this article, we explore the ability of direct and indirect dark matter
experiments to not only detect neutralino dark matter, but to constrain and
measure the parameters of supersymmetry. In particular, we explore the
relationship between the phenomenological quantities relevant to dark matter
experiments, such as the neutralino annihilation and elastic scattering cross
sections, and the underlying characteristics of the supersymmetric model, such
as the values of mu (and the composition of the lightest neutralino), m_A and
tan beta. We explore a broad range of supersymmetric models and then focus on a
smaller set of benchmark models. We find that by combining astrophysical
observations with collider measurements, mu can often be constrained far more
tightly than it can be from LHC data alone. In models in the A-funnel region of
parameter space, we find that dark matter experiments can potentially determine
m_A to roughly +/-100 GeV, even when heavy neutral MSSM Higgs bosons (A, H_1)
cannot be observed at the LHC. The information provided by astrophysical
experiments is often highly complementary to the information most easily
ascertained at colliders.Comment: 46 pages, 76 figure
Воспитание толерантности в процессе преподавания гуманитарных дисциплин
Objective: To assess whether patient characteristics add to the fetal fibronectin test and cervical length measurement in the prediction of preterm delivery in symptomatic women. Study design: A nationwide prospective cohort study was conducted in all ten perinatal centres in the Netherlands. Women with symptoms of preterm labour between 24 and 34 weeks gestation with intact membranes were invited. In all women qualitative fibronectin testing (0.050 tig/mL cut-off) and cervical length measurement were performed. Only singleton pregnancies were included in this analysis. Logistic regression was used to construct two multivariable models to predict spontaneously delivery within 7 days: a model including cervical length and fetal fibronectin as predictors, and an extended model including all potential predictors. The models were internally validated using bootstrapping techniques. Predictive performances were assessed as the area under the receiver operator characteristic curve (AUC) and calibration plots. We compared the models' capability to identify women with a low risk to deliver within 7 days. A risk less than 5%, corresponding to the risk for women with a cervical length of at least 25 mm, was considered as low risk. Results: Seventy-three of 600 included women (12%) had delivered spontaneously within 7 days. The extended model included maternal age, parity, previous preterm delivery, vaginal bleeding, C-reactive protein, cervical length, dilatation and fibronectin status. Both models had high discriminative performances (AUC of 0.92 (95% CI 0.88-0.95) and 0.95 (95% CI 0.92-0.97) respectively). Compared to the model with fibronectin and cervical length, our extended model reclassified 38 women (6%) from low risk to high risk and 21 women (4%) from high risk to low risk. Preterm delivery within 7 days occurred once in both the reclassification groups. Conclusion: In women with symptoms of preterm labour before 34 weeks gestation, a model that integrates maternal characteristics, clinical signs and laboratory tests, did not predict delivery within 7 days better than a model with only fibronectin and cervical length. (C) 2015 Elsevier Ireland Ltd. All rights reserved
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