19,902 research outputs found
Using ForeCAT Deflections and Rotations to Constrain the Early Evolution of CMEs
To accurately predict the space weather effects of coronal mass ejection
(CME) impacts at Earth one must know if and when a CME will impact Earth, and
the CME parameters upon impact. Kay et al. (2015b) presents Forecasting a CME's
Altered Trajectory (ForeCAT), a model for CME deflections based on the magnetic
forces from the background solar magnetic field. Knowing the deflection and
rotation of a CME enables prediction of Earth impacts, and the CME orientation
upon impact. We first reconstruct the positions of the 2008 April 10 and the
2012 July 12 CMEs from the observations. The first of these CMEs exhibits
significant deflection and rotation (34 degrees deflection and 58 degrees
rotation), while the second shows almost no deflection or rotation (<3 degrees
each). Using ForeCAT, we explore a range of initial parameters, such as the CME
location and size, and find parameters that can successfully reproduce the
behavior for each CME. Additionally, since the deflection depends strongly on
the behavior of a CME in the low corona (Kay et al. (2015a, 2015b)), we are
able to constrain the expansion and propagation of these CMEs in the low
corona.Comment: accepted in Ap
Theoretical dynamic analysis of the landing loads on a vehicle with a tricycle landing gear
Theoretical dynamic analysis of landing loads on vehicle with tricycle landing gear compared with X-15 aircraft dat
The Freezing of Random RNA
We study secondary structures of random RNA molecules by means of a
renormalized field theory based on an expansion in the sequence disorder. We
show that there is a continuous phase transition from a molten phase at higher
temperatures to a low-temperature glass phase. The primary freezing occurs
above the critical temperature, with local islands of stable folds forming
within the molten phase. The size of these islands defines the correlation
length of the transition. Our results include critical exponents at the
transition and in the glass phase.Comment: 4 pages, 8 figures. v2: presentation improve
Using foreCAT deflections and rotations to constrain the early evolution of CMEs
To accurately predict the space weather effects of the impacts of coronal mass ejection (CME) at Earth one must know if and when a CME will impact Earth and the CME parameters upon impact. In 2015 Kay et al. presented Forecasting a CME's Altered Trajectory (ForeCAT), a model for CME deflections based on the magnetic forces from the background solar magnetic field. Knowing the deflection and rotation of a CME enables prediction of Earth impacts and the orientation of the CME upon impact. We first reconstruct the positions of the 2010 April 8 and the 2012 July 12 CMEs from the observations. The first of these CMEs exhibits significant deflection and rotation (34° deflection and 58° rotation), while the second shows almost no deflection or rotation (<3° each). Using ForeCAT, we explore a range of initial parameters, such as the CME's location and size, and find parameters that can successfully reproduce the behavior for each CME. Additionally, since the deflection depends strongly on the behavior of a CME in the low corona, we are able to constrain the expansion and propagation of these CMEs in the low corona.C.K.'s research was supported by an appointment to the NASA Postdoctoral Program at NASA GSFC, administered by the Universities Space Research Association under contract with NASA. A.V. acknowledges support from JHU/APL. R.C.C. acknowledges the support of NASA contract S-136361-Y to NRL. The SECCHI data are produced by an international consortium of the NRL, LMSAL, and NASA GSFC (USA), RAL and Univ. of Birmingham (UK), MPS (Germany), CSL (Belgium), IOTA and IAS (France). (JHU/APL; S-136361-Y - NASA)Published versio
Continuity of symplectically adjoint maps and the algebraic structure of Hadamard vacuum representations for quantum fields on curved spacetime
We derive for a pair of operators on a symplectic space which are adjoints of
each other with respect to the symplectic form (that is, they are sympletically
adjoint) that, if they are bounded for some scalar product on the symplectic
space dominating the symplectic form, then they are bounded with respect to a
one-parametric family of scalar products canonically associated with the
initially given one, among them being its ``purification''. As a typical
example we consider a scalar field on a globally hyperbolic spacetime governed
by the Klein-Gordon equation; the classical system is described by a symplectic
space and the temporal evolution by symplectomorphisms (which are
symplectically adjoint to their inverses). A natural scalar product is that
inducing the classical energy norm, and an application of the above result
yields that its ``purification'' induces on the one-particle space of the
quantized system a topology which coincides with that given by the two-point
functions of quasifree Hadamard states. These findings will be shown to lead to
new results concerning the structure of the local (von Neumann)
observable-algebras in representations of quasifree Hadamard states of the
Klein-Gordon field in an arbitrary globally hyperbolic spacetime, such as local
definiteness, local primarity and Haag-duality (and also split- and type
III_1-properties). A brief review of this circle of notions, as well as of
properties of Hadamard states, forms part of the article.Comment: 42 pages, LaTeX. The Def. 3.3 was incomplete and this has been
corrected. Several misprints have been removed. All results and proofs remain
unchange
Mesoscopic Model for Diffusion-Influenced Reaction Dynamics
A hybrid mesoscopic multi-particle collision model is used to study
diffusion-influenced reaction kinetics. The mesoscopic particle dynamics
conserves mass, momentum and energy so that hydrodynamic effects are fully
taken into account. Reactive and non-reactive interactions with catalytic
solute particles are described by full molecular dynamics. Results are
presented for large-scale, three-dimensional simulations to study the influence
of diffusion on the rate constants of the A+CB+C reaction. In the limit of
a dilute solution of catalytic C particles, the simulation results are compared
with diffusion equation approaches for both the irreversible and reversible
reaction cases. Simulation results for systems where the volume fraction of
catalytic spheres is high are also presented, and collective interactions among
reactions on catalytic spheres that introduce volume fraction dependence in the
rate constants are studied.Comment: 9 pages, 5 figure
The generic character table of a Sylow -subgroup of a finite Chevalley group of type
Let be a Sylow -subgroup of the finite Chevalley group of type
over the field of elements, where is a power of a prime . We
describe a construction of the generic character table of
Carboplatin binding to a model protein in non-NaCl conditions to eliminate partial conversion to cisplatin, and the use of different criteria to choose the resolution limit
Hen egg white lysozyme (HEWL) co-crystallisation conditions of carboplatin
without sodium chloride (NaCl) have been utilised to eliminate partial
conversion of carboplatin to cisplatin observed previously. Tetragonal HEWL
crystals were successfully obtained in 65% MPD with 0.1M citric acid buffer at
pH 4.0 including DMSO. The X-ray diffraction data resolution to be used for the
model refinement was reviewed using several topical criteria together. The
CC1/2 criterion implemented in XDS led to data being significant to 2.0{\AA},
compared to the data only being able to be processed to 3.0{\AA} using the
Bruker software package (SAINT). Then using paired protein model refinements
and DPI values based on the FreeR value, the resolution limit was fine tuned to
be 2.3{\AA}. Interestingly this was compared with results from the EVAL
software package which gave a resolution limit of 2.2{\AA} solely using
crossing 2, but 2.8{\AA} based on the Rmerge values (60%). The
structural results showed that carboplatin bound to only the N{\delta} binding
site of His-15 one week after crystal growth, whereas five weeks after crystal
growth, two molecules of carboplatin are bound to the His-15 residue. In
summary several new results have emerged: - firstly non-NaCl conditions showed
a carboplatin molecule bound to His-15 of HEWL; secondly binding of one
molecule of carboplatin was seen after one week of crystal growth and two
molecules were bound after five weeks of crystal growth; and thirdly the use of
several criteria to determine the diffraction resolution limit led to the
successful use of data to higher resolution.Comment: 14 pages; submitted to Acta Cryst D Biological Crystallography
reference number tz504
The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension
Peer reviewedPostprin
The effect of radiative cooling on scaling laws of X-ray groups and clusters
We have performed cosmological simulations in a ÎCDM cosmology with and without radiative cooling in order to study the effect of cooling on the cluster scaling laws. Our simulations consist of 4.1 million particles each of gas and dark matter within a box size of 100 h-1 Mpc, and the run with cooling is the largest of its kind to have been evolved to z = 0. Our cluster catalogs both consist of over 400 objects and are complete in mass down to ~1013 h-1 Mâ. We contrast the emission-weighted temperature-mass (Tew-M) and bolometric luminosity-temperature (Lbol-Tew) relations for the simulations at z = 0. We find that radiative cooling increases the temperature of intracluster gas and decreases its total luminosity, in agreement with the results of Pearce et al. Furthermore, the temperature dependence of these effects flattens the slope of the Tew-M relation and steepens the slope of the Lbol-Tew relation. Inclusion of radiative cooling in the simulations is sufficient to reproduce the observed X-ray scaling relations without requiring excessive nongravitational energy injection
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