Miracle-dz/UniFAR-FTUs huggingface dataset:
Hydrogenation and Charge States of Polycyclic Aromatic Hydrocarbons in Diffuse Clouds. II. Results

We have modeled the states of hydrogenation and charge of polycyclic aromatic hydrocarbons (PAHs) in diffuse clouds for molecules ranging from benzene up to species containing 200 carbon atoms. It is found that the hydrogenation state of PAHs strongly depends on the size of the molecule. Small PAHs with fewer than about 15-20 carbon atoms are destroyed in most environments. Intermediate-size PAHs in the range of 20-30 carbon atoms are stripped of most of their peripheral hydrogen atoms, but may be able to survive in the interstellar medium because of the relative stability of their carbon skeleton upon UV photon absorption. Larger PAHs primarily have normal hydrogen coverage (i.e., with each peripheral carbon atom bearing a single hydrogen), with competition between this form and PAHs containing an additional hydrogen. Very large PAHs may be fully hydrogenated, with every peripheral carbon atom bearing two hydrogen atoms. Our finding that extremely dehydrogenated PAH neutrals or positively charged CmH, with m ranging from 15 to 30 and n ≤ 2, can survive in the interstellar medium contrasts with previous work, where it was generally assumed that PAHs losing their hydrogen coverage were quickly destroyed. A mechanism is proposed for the selective growth of these small dehydrogenated PAHs in diffuse clouds with respect to larger PAHs. Finally, our results are compared to previous studies on the hydrogenation and charge states of PAHs.
High Minor Ion Outflow Speeds in the Inner Corona and Observed Ion Charge States in Interplanetary Space

Flow speeds recently derived from chromospheric/transition region and coronal observations indicate that the solar wind acceleration process takes place at heights in the solar atmosphere much lower than previously imagined. Doppler-dimming observations of the O VI λ1032 and λ1037 spectral lines show that this is not only true for the background electron-proton solar wind but also for minor ions. The limits that these observations place on the flow speed of the O+5 ions are at least a factor of 3-4 higher than the highest flow speeds expected from earlier minor ion studies. It is likely that other ions reach similar speeds in the inner corona. The interpretation of in situ charge state observations needs to be reexamined in light of these new velocity measurements. Large flow speeds imply that some species may not be close to equilibrium in the inner corona at any distance. Given a large deviation from equilibrium, the use of charge state ratios to determine equilibrium temperatures may no longer be appropriate. Using the newest available atomic data together with the most recent observational constraints on electron temperatures, electron densities, and flow speeds, we find models with high minor ion outflow speeds of the order of the O+5 outflow speed (about 130-230 km s-1 below 3 R☉) that are consistent with charge state observations. We then discuss how minor ion charge state observations can be used in future observational and theoretical studies to place limits on solar wind acceleration and heating mechanisms.
Complete solution to the TP2 completion problem

For any pattern of the specified entries, an explicit finite list of polynomial inequalities in the specified entries is given that characterizes the completability of a partial positive matrix to a TP matrix. Each polynomial happens to be a monomial, and an algorithm, whose input is the pattern, is given for finding the polynomials. The method uses some new partial orders on matrices and the logarithmic method to reduce the question to determining the generators of a certain finitely generated, pointed cone.
New Results on the Vibrating String with a Continuous Obstacle

We give an explicit formula which describes the solution of the problem of the linear elastic string vibrating against a plane obstacle without loss of energy. This formula allows us to prove continuous dependence on the initial data; a regularity result in some bounded variation spaces is given. A numerical scheme is deduced from the explicit formula.Finally we prove the weak convergence of a subsequence of solutions of the penalized problem to a “weak” solution (i.e. one which does not necessarily conserve energy) of the problem with an obstacle when the obstacle is arbitrary; when the obstacle is plane, all the sequence strongly converges to the solution of the obstacle problem which conserves the energy.
Virtual sound imaging using visually adaptive loudspeakers

Advances in computer technology and low cost cameras open up new possibilities for three dimensional (3D) sound reproduction. The idea is to create 3D sound using loudspeakers and visual tracking of the position of the listener. Previously, applications of binaural technology using loudspeakers have been limited due to the small sweet spot of such systems. Recently visual tracking has emerged as a feasible option for overcoming these limitations. Although it is a difficult task to predict the position of the listener relative to the loudspeakers in any given situation, under certain conditions it is possible to track the position of the listener relative to the loudspeakers. Here it is shown that it is possible to track the position of a listener that is not wearing any sensors by using image processing techniques, while the audio system is adapted using filter update techniques that are seamless as far as the audible perception of the listener is concerned.
On L/sup 2/-sensitivity minimization of linear state-space systems

Properties of the solution to the L/sup 2/-sensitivity minimization problem are discussed. In particular, a specific form of the solution is derived together with a bound. This bound gives an insight into the difference between a pure L/sup 2/-sensitivity optimal realization, and a mixed L/sup 2//L/sup 1/-sensitivity optimal one. The question of L/sup 2/-sensitivity balanced truncation is addressed, and a counterexample is presented to show that two main properties associated with model reduction by truncating a Lyapunov balanced realization are lost in the case of L/sup 2/-sensitivity balanced truncation. <<ETX>>
Histogram-based reversible data hiding for vector quantisation-compressed images

Reversible data hiding is required and preferable in many applications such as medical diagnosis, military, law enforcement, fine art work and so on. The author proposes to use reversible data hiding applications with a vector quantisation (VQ)-compressed image. The histogram of the prediction VQ-compressed image is explored. The prediction VQ encoded image is identical to traditional VQ encoding. The index of prediction encoded VQ images is modified to embed secret data. Furthermore, the VQ images can be completely reconstructed by the recovery procedure. The experimental results show the performance of the proposed method and the efficiency of the embedding, extraction and recovery procedures. In comparison with other VQ-based schemes, the proposed method provides a higher hiding capacity and a better stego-image quality. Also, the lossless VQ image is recovered.
Far-infrared emission in the Rho Ophiuchi region - A comparison with molecular gas emission and visual extinction

The dust characteristics of a 40 arcmin x 40 arcmin section of the Rho Ophiuchi molecular clouds complex revealed by the IRAS satellite are compared with both molecular line and deep star count data for the region. The data reveal the cloud to be clearly visible at 12 and 25 microns, as well as at 60 and 100 microns. Modeling the infrared emission from the cloud as being due to two populations of dust grains, the short-wavelength emission is found not to reflect the internal structure of the molecular cloud. The 60 micron opacity determined using a single grain emission model correlates reasonably well with (C-13)O column density and visual extinction up to roughly 5 mag. The cloud edges appear to be heated by the interstellar radiation field. The far-infrared luminosity to mass ratio for the region is determined to be 0.9 solar luminosity/solar mass, a value much smaller than the average ratio for the inner Galaxy. 50 refs.
A novel method for determining the anchoring energy function at a nematic liquid crystal‐wall interface from director distortions at high fields

We show that the anchoring energy function, i.e., the anisotropic part of the interfacial free energy, at a nematic liquid crystal‐wall interface can be determined uniquely without a numerical fitting procedure, when the integrated birefringence of a liquid crystal cell with a thickness much larger than the extrapolation length is measured as a function of an electric or magnetic field well above the Freedericksz threshold. The precision of the present method is closely argued, showing that the resulting anchoring energy function is reasonably insensitive to the uncertainties in the material parameters and in the cell thickness. As an example, the anchoring energy function at the interface between 5CB(pentylcyanobiphenyl) and an obliquely evaporated SiO was determined for the first time, by measuring the birefringence and the capacitance of a 56‐μm‐thick cell up to 150 V rms at 0.23 °C below the clearing temperature. A saturation of the field‐induced distortion was clearly observed at about 100 V rms. The.
Sequential BKW-Operators and Function Algebras

The Korovkin-type approximation theory for function algebras is studied. A complete characterization of the BKW-operators studied by Takahasi is given for function algebras, and this answers Altomare's conjecture affirmatively. As an application, the BKW-operators on the disk algebra for test functions {1, z} are determined.
Nanoelectromechanical switches based on carbon nanotubes for microwave and millimeter waves

In this letter the authors analyze two configurations of nanoelectromechanical switches, which are working in the microwave and millimeter wave frequency ranges. Metallic nanotubes vertically or horizontally positioned on a propagating high frequency planar waveguide disable or enable the electromagnetic field propagation, whether they are actuated or not by a dc electric field of a few volts. Although the dimensions of metallic nanotubes are very small in comparison with the planar waveguide dimensions and the operating wavelengths, these switches are very efficient and agile.
Kinetic Alfven waves as a source of plasma transport at the dayside magnetopause

As the shocked solar wind with variable plasma density and magnetic field impinges on the dayside magnetopause, it is likely to generate large-scale Alfven waves at the solar wind magnetosphere interface. However, large gradients in the density and magnetic field at the magnetopause boundary effectively couple large-scale Alfven waves with kinetic Alfven waves may play an important role in plasma transport at the dayside magnetopause and in electron acceleration along field lines. The transport can occur because, unlike the magnetohydrodynamic (MHD) shear Alfven wave, the kinetic Alfven wave has an associated parallel electric field which breaks down the 'frozen-in' condition and decouples the plasma from field lines. We calculate the average deviation of the plasma from the field line from which we estimate the diffusion coefficient associated with these 'bundles' of lead to acceleration of electrons along field lines in the magnetopause boundary and may possibly provide an explanation for observed counterstreaming electron beams characterized by energies of 50-200 eV.
A genuinely multidimensional high-resolution scheme for the elastic-plastic wave equation

In this paper we present a numerical method of high order for solving the multidimensional elastic-plastic wave equation. The basic idea is to decompose the hyperbolic PDE into advection equations, which can be solved numerically. Furthermore, the occurrence of plasticity makes it necessary to solve an ODE for the stress-strain relationship at evey point.
Kinematic, Dynamic, and Thermodynamic Analysis of a Weakly Sheared Severe Thunderstorm over Northern Alabama

Abstract A kinematic, dynamic, and thermodynamic analysis of a weakly sheared, airmass thunderstorm observed over northern Alabama is presented. Most notable is the fact that the dominant cell in this storm closely resembles the Byers and Braham model for warm-based, airmass storms. Several phenomena never documented for this storm-type are discussed. One of these is a strong and deep downdraft observed at midlevels with an associated “weak-echo” trench. Its origin appears to be related to a wake entrainment process. A midlevel inflow which causes a visible constriction in the storm cloud is also observed. This inflow results in a division of the thermal buoyancy into two maxima in the vertical: one associated with the precipitation core and the other with strong positive vertical motions in the growing cumulus turret. In addition, a downdraft separate from that seen at midlevels develops at low levels and causes a microburst outflow at the surface. This downdraft appears to be initiated by precipitation .
A Production Mechanism for Clusters of Dense Cores

Collapse and fragmentation processes within filamentary interstellar molecular clouds are investigated in detail. A quasi-equilibrium filament fragments into dense cores separated by about 4 times the filament diameter. Nonlinear calculations reveal that the central region of each core tends toward spherical collapse and further hierarchical fragmentation is not expected. However, merging and clustering of cores tend to occur soon after the fragmentation. When the line mass of an isothermal filament exceeds the critical value for equilibrium by a small amount, perturbations do not grow much, and the entire filament collapses toward the axis without fragmenting. In this case no characteristic scale for fragmentation appears during the isothermal collapse phase. Subsequent evolution is also investigated. A change of the equation of state yields a characteristic density, separation length, and mass for fragmentation. These values correspond to 5 × 10-15 g cm-3, 2 × 10-3 pc, and 4 × 10-2 M☉, if the cloud temperature is 10 K. These results are consistent with recent high-resolution radio observations of dense cores in Taurus dark cloud.
Plastid Phylogenomics of Paeonia and the Evolution of Ten Flower Types in Tree Peony

Paeonia suffruticosa Andr. , a member of Paeoniaceae, is native to China. In its 1600 years’ cultivation, more than 2000 cultivars for different purposes (ornamental, medicinal and oil use) have been inbred. However, there are still some controversies regarding the provenance of tree peony cultivars and the phylogenetic relationships between and within different cultivar groups. In this study, plastid genome sequencing was performed on 10 representative tree peony cultivars corresponding to 10 different flower types. Structure and comparative analyses of the plastid genomes showed that the total lengths of the chloroplast genome of the 10 cultivars ranged from 152,153 to 152,385 bp and encoded 84–88 protein-coding genes, 8 rRNAs and 31–40 tRNAs. The number of simple sequence repeats and interspersed repeat sequences of the 10 cultivars ranged from 65–68 and 40–42, respectively. Plastid phylogenetic relationships of Paeonia species/cultivars were reconstructed incorporating data from our newly sequenced plastid genomes and 15 published species, and results showed that subsect. Vaginatae was the closest relative to the central plains cultivar group with robust support, and that it may be involved in the formation of the group. Paeonia ostii was recovered as a successive sister group to this lineage. Additionally, eleven morphological characteristics of flowers were mapped to the phylogenetic skeleton to reconstruct the evolutionary trajectory of flower architecture in Paeoniaceae.
Characterization of a Pseudokeronopsis Strain (Ciliophora, Urostylida) and Its Bacterial Endosymbiont “Candidatus Trichorickettsia” (Alphaproteobacteria, Rickettsiales)

Symbiotic associations between bacteria and ciliate protists are rather common. In particular, several cases were reported involving bacteria of the alphaproteobacterial lineage Rickettsiales, but the diversity, features, and interactions in these associations are still poorly understood. In this work, we characterized a novel ciliate protist strain originating from Brazil and its associated Rickettsiales endosymbiont by means of live and ultrastructural observations, as well as molecular phylogeny. Though with few morphological peculiarities, the ciliate was found to be phylogenetically affiliated with Pseudokeronopsis erythrina, a euryhaline species, which is consistent with its origin from a lagoon with significant spatial and seasonal salinity variations. The bacterial symbiont was assigned to “Candidatus Trichorickettsia mobilis subsp. hyperinfectiva”, being the first documented case of a Rickettsiales associated with urostylid ciliates. It resided in the host cytoplasm and bore flagella, similarly to many, but not all, conspecifics in other host species. These findings highlight the ability of “Candidatus Trichorickettsia” to infect multiple distinct host species and underline the importance of further studies on this system, in particular on flagella and their regulation, from a functional and also an evolutionary perspective, considering the phylogenetic proximity with the well-studied and non-flagellated Rickettsia.
Contrast Analysis of Solar Faculae and Magnetic Bright Points

The morphology and contrast of small-scale solar magnetic elements at four disk positions is analyzed. The data were obtained at the Swedish 1 m Solar Telescope (SST) over 3 yr (2003-2005). Two of the data sets have disk positions near disk center (average μ = cos θ > 0.8) and show numerous "magnetic bright points" (MBPs), and two are sufficiently limbward to show prominent "faculae" (average μ ≤ 0.6). The filtergrams are obtained in the 430.5 nm G band and 436.4 nm "continuum" bandpasses; the magnetograms are Fe I 630.25 nm Stokes V images taken with the Solar Optical Universal Polarimeter (SOUP) tunable filter. In all images we achieve nearly diffraction-limited resolution (~100 km in the G band). Analysis shows that MBPs and faculae are distinct radiative signatures of the magnetic field: MBPs have a constant or slightly decreasing contrast with increasing magnetogram signal, while facular contrast increases linearly with magnetogram signal. Faculae are much larger than MBPs, with an average radial width of 400 km. The observations support recent modeling showing that faculae are granules seen through the opacity reduction provided by magnetic elements (or groups thereof), while MBPs are caused by lateral radiation leakage scattering from deeper layers of the magnetic element.
Some sensitivities of a coupled ocean-atmosphere GCM

A coupled ocean-atmosphere GCM is being developed for use in seasonal forecasting. As part of the development work, a number of experiments have been made to explore some of the sensitivities of the coupled model system. The overall heat balance of the tropics is found to be very sensitive to convective cloud cover. Adjusting the cloud parameterization to produce stable behaviour of the coupled model also leads to better agreement between model radiative fluxes and satellite data. A further sensitivity is seen to changes in low-level marine stratus, which is under-represented in the initial model experiments. An increase in this cloud in the coupled model produces a small improvement in both the global mean state and the phase of the east Pacific annual cycle. The computational expense of investigating such small changes is emphasized. An indication of model sensitivity to surface albedo is also presented. The sensitivity of the coupled GCM to initial conditions is investigated. The model is very sensitive, with tiny perturbations able to determine El Nino or non-El Nino conditions just six months later. This large sensitivity may be related to the relatively weak amplitude of the model ENSO cycle. DOI: 10.1034/j.1600-0870.1994. t01-3-00004.x
The finite volume element method for diffusion equations on general triangulations

This paper develops discretization error estimates for the finite volume element method on general triangulations of a polygonal domain in $\mathcal{R}^2 $ using a special type of control volume. The theory applies to diffusion equations of the form \[ \begin{gathered} - \nabla (A\nabla u) = f\quad {\text{in }}\Omega , \hfill \\ u = 0\quad {\text{on }}\partial \Omega . \hfill \\ \end{gathered} \] Under fairly general conditions, the theory establishes $O(h)$ estimates of the error in a discrete $\mathcal{H}^1 $ seminorm. Under an additional assumption concerning local uniformity of the triangulation, the estimate is improved to $O(h^2 )$.
Numerical investigation of the possibility of macroscopic turbulence in porous media: a direct numerical simulation study

Abstract When a turbulent flow in a porous medium is determined numerically, the crucial question is whether turbulence models should account only for turbulent structures restricted in size to the pore scale or whether the size of turbulent structures could exceed the pore scale. The latter would mean the existence of macroscopic turbulence in porous media, when turbulent eddies exceed the pore size. In order to determine the real size of turbulent structures in a porous medium, we simulated the turbulent flow by direct numerical simulation (DNS) calculations, thus avoiding turbulence modelling of any kind. With this study, which for the first time uses DNS calculations, we provide benchmark data for turbulent flow in porous media. Since perfect DNS calculations require the resolution of scales down to the Kolmogorov scale, often only approximate DNS solutions can be obtained, especially for high Reynolds numbers. This is accounted for by using and comparing two different DNS approaches, a finite volume method (FVM) with grid refinement towards the wall and a lattice Boltzmann method (LBM) with equal grid distribution. The solid matrix was simulated by a large number of rectangular bars arranged periodically. The number of bars in the solution domain with periodic boundary conditions was reduced systematically until a minimum size was found that does not suppress any large-scale turbulent structures. Two-point correlations, integral length scales and energy spectra were determined in order to answer the question of whether or not macroscopic turbulence can be found in porous media.
Ozone Profile Retrieval from an Advanced Infrared Sounder: Experiments with Tropopause-Based Climatology and Optimal Estimation Approach

Abstract Motivated by a significant potential for retrieving atmospheric ozone profile information from advanced satellite infrared sounders, this study investigates various methods to optimize ozone retrievals. A set of retrieval experiments has been performed to assess the impact of different background states (or the a priori states) and retrieval algorithms on the retrieved ozone profiles in the upper troposphere and lower stratosphere (UTLS) using Atmospheric Infrared Sounder (AIRS) measurements. A new tropopause-based ozone climatology, using publicly available global ozonesonde data to construct the a priori state, is described. Comparisons are made with the AIRS version 5 (v5) ozone climatology. The authors also present the result of a newly implemented optimal estimation (OE) algorithm and compare it to the current AIRS science team (AST) algorithm used in version 5. The ozone climatology using tropopause-referenced coordinates better preserves the shape and the magnitude of the ozone gradient ac.