Miracle-dz/UniFAR-FTUs huggingface dataset:
How primordial is the structure of comet 67P? - Combined collisional and dynamical models suggest a late formation

Context. There is an active debate about whether the properties of comets as observed today are primordial or, alternatively, if they are a result of collisional evolution or other processes. Aims. We investigate the effects of collisions on a comet with a structure like 67P/Churyumov-Gerasimenko (67P). We develop scaling laws for the critical specific impact energies Q reshape required for a significant shape alteration. These are then used in simulations of the combined dynamical and collisional evolution of comets in order to study the survival probability of a primordially formed object with a shape like 67P. Although the focus of this work is on a structure of this kind, the analysis is also performed for more generic bi-lobe shapes, for which we define the critical specific energy Q bil . The simulation outcomes are also analyzed in terms of impact heating and the evolution of the porosity. Methods. The effects of impacts on comet 67P are studied using a state-of-the-art smooth particle hydrodynamics shock physics code. In the 3D simulations, a publicly available shape model of 67P is applied and a range of impact conditions and material properties are investigated. The resulting critical specific impact energy Q reshape (as well as Q bil for generic bi-lobe shapes) defines a minimal projectile size which is used to compute the number of shape-changing collisions in a set of dynamical simulations. These simulations follow the dispersion of the trans-Neptunian disk during the giant planet instability, the formation of a scattered disk, and produce 87 objects that penetrate into the inner solar system with orbits consistent with the observed JFC population. The collisional evolution before the giant planet instability is not considered here. Hence, our study is conservative in its estimation of the number of collisions. Results. We find that in any scenario considered here, comet 67P would have experienced a significant number of shape-changing collisions, if it formed primordially. This is also the case for generic bi-lobe shapes. Our study also shows that impact heating is very localized and that collisionally processed bodies can still have a high porosity. Conclusions. Our study indicates that the observed bi-lobe structure of comet 67P may not be primordial, but might have originated in a rather recent event, possibly within the last 1 Gy. This may be the case for any kilometer-sized two-component cometary nuclei.
Anti-Pollution Activity, Antioxidant and Anti-Inflammatory Effects of Fermented Extract from Smilax china Leaf in Macrophages and Keratinocytes

Air pollution has considerable effects on the human skin, showing that every single pollutant has a different toxicological impact on it. The oxidative stress that exceeds the skin’s antioxidant capacity can lead to oxidative damage and premature skin aging by repeated air pollutant contact. In this study, according to the generalized protocol available to objectively substantiate the ‘anti-pollution’ claim, we evaluated several biomarkers after pollutants exposure in Raw 264.7 macro-phages and HaCaT keratinocytes to investigate the possibility of anti-pollution cosmetic material of fermented extract from Smilax china leaves (FESCL). FESCL decreased pollutants-induced luciferase activity in a dose-dependent manner, and FESCL significantly inhibited XRE-luciferase activity at a concentration of 1%. The IC50 value of FESCL showed the same DPPH scavenging activity at 0.0625% as ascorbic acid, and the maximum DPPH scavenging activity (92.44%) at 1%. The maximum permissible non-cytotoxic concentrations of FESCL for a Raw 264.7 cell was determined to be 2%, where PGE2 production of FESCL was inhibited by 78.20%. These results show the anti-pollution activity of FESCL against the pollutant-stimulated human living skin explants. In conclusion, we confirmed the anti-pollution potential of FESCL as one of the functional materials in cosmetic formulation.
Limited Effects of Pain Control Treatments on Behaviour and Weight Gain of Pure and Crossbred Nellore Heifer Calves When Subjected to Hot-Iron Branding

Simple Summary This study investigated the effects of pain relief treatments on behaviour and weight gain in 92 Nellore and crossbred (F1 Aberdeen Angus × Nellore) heifer calves (aged around 120 days) subjected to hot-iron branding on the cheek after vaccination against brucellosis. Four treatments were compared: Control (CO, no pain relief); local anaesthesia (LA, subcutaneous anaesthetic); analgesic (LT, intramuscular meloxicam); and local anaesthetic and analgesic (LL, both local anaesthesia and meloxicam). Calves in treatments CO and LT were subjected to face manipulation simulating application of local anaesthetic without introducing the needle. Facial and body expressions, flight speed, and body weight were recorded before, during, and five (5-d) and 60 days (60-d) after hot-iron branding. No effect of pain relief was observed for most calves studied. The only difference observed was higher tension (‘tense’) at 5-d in CO calves. All calves showed fear and stress responses during restraint and hot-iron branding, which probably masked pain responses. In conclusion, hot-iron facial branding impoverishes calf welfare and, due to the additional handling involved, adoption of a pain relief protocol is not an efficient way to minimise welfare impacts. Abstract Hot-iron branding is still commonly performed in cattle farming in tropical countries, and possibly has negative consequences for animal welfare and weight gain. This study examined the behavioural and weight gain responses of pure and crossbred Nellore heifer calves subjected to hot-iron branding on the cheek, without and with use of anaesthesia and analgesia. Ninety-two heifer calves, around 120 days old, were studied prospectively when subjected to hot-iron branding on the cheek (a statutory procedure in Brazil following brucellosis vaccination). Four randomly selected groups of calves were allocated to four treatments: no pain control (CO); subcutaneous anaesthetic local block (LA); intramuscular analgesia (meloxicam) (LT); and local anaesthesia plus meloxicam (LL). Behaviour, flight speed and body weight were evaluated before, during, and five (5-d) and 60 days (60-d) after branding. For these parameters, the only difference observed was higher tension in the CO group 5-d post-branding, suggesting a short-term negative effect of branding without pain control. The limited effects of the pain control treatments suggest interference in pain assessment by other factors, such as expression of fear and stress. Despite the lack of differences observed in behaviour and production parameters, facial hot-iron branding is an obvious welfare issue and, due to the additional handling involved, adoption of a simple pain relief protocol is not sufficient to minimise the welfare impact.
Magnetic Helix Formation Driven by Keplerian Disk Rotation in an External Plasma Pressure: The Initial Expansion Stage

We study the evolution of a magnetic arcade that is anchored to an accretion disk and is sheared by the differential rotation of a Keplerian disk. By including an extremely low external plasma pressure at large distances, we obtain a sequence of axisymmetric magnetostatic equilibria and show that there is a fundamental difference between field lines that are affected by the plasma pressure and those that are not (i.e., force free). Force-free fields, while being twisted by the differential rotation of the disk, expand outward at an angle of ~60° away from the rotation axis, consistent with the previous studies. These force-free field lines, however, are enclosed by the outer field lines, which originate from small disk radii and come back to the disk at large radii. These outer fields experience most of the twist, and they are also affected most by the external plasma pressure. At large cylindrical radial distances, magnetic pressure and plasma pressure are comparable so that any further radial expansion of magnetic fields is prevented or slowed down greatly by this pressure. This hindrance to cylindrical radial expansion causes most of the added twist to be distributed on the ascending portion of the field lines, close to the rotation axis. Since these field lines are twisted most, the increasing ratio of the toroidal Bϕ component to the poloidal component BR,z eventually results in the collimation of magnetic energy and flux around the rotation axis. We discuss the difficulty with adding a large number of twists within the limitations of the magnetostatic approximation.
Bolometric arrays and infrared sensitivity of VO2 films with varying stoichiometry

Here we propose a linear microbolometric array based on VOx thin films. The linear microbolometric array is fabricated by using micromachining technology, and its thermo-sensitive VOx thin film has excellent infrared response spectrum and TCR characteristics. Nano-scale VOx thin films deposited on SiO2/Si substrates were obtained by e-beam vapor deposition. The VOx films were then annealed at temperatures between 300 to 500 C with various deposition duration time. The crystal structures and microstructures were examined by XRD, SEM and ESCA. These films showed a predominant phase of rhombohedral VO2 and the crystallinity of the VO2 increased as the annealing temperature increased. Integrated with CMOS circuit, an experimentally prototypical monolithic linear microbolometric array is designed and fabricated. The testing results of the experimental linear array show that the responsivity of linear array can approach 18KV/W and is potential for infrared image systems.
A New Stellar Atmosphere Grid and Comparisons with HST/STIS CALSPEC Flux Distributions

The Space Telescope Imaging Spectrograph has measured the spectral energy distributions for several stars of types O, B, A, F, and G. These absolute fluxes from the CALSPEC database are fit with a new spectral grid computed from the ATLAS-APOGEE ATLAS9 model atmosphere database using a chi-square minimization technique in four parameters. The quality of the fits are compared for complete LTE grids by Castelli & Kurucz (CK04) and our new comprehensive LTE grid (BOSZ). For the cooler stars, the fits with the MARCS LTE grid are also evaluated, while the hottest stars are also fit with the NLTE Lanz & Hubeny OB star grids. Unfortunately, these NLTE models do not transition smoothly in the infrared to agree with our new BOSZ LTE grid at the NLTE lower limit of Teff = 15,000 K. The new BOSZ grid is available via the Space Telescope Institute MAST archive and has a much finer sampled IR wavelength scale than CK04, which will facilitate the modeling of stars observed by the James Webb Space Telescope. Our result for the angular diameter of Sirius agrees with the ground-based interferometric value.
How surface magnetism affects helioseismic waves

Abstract It has been known for two decades that sunspots both absorb and advance the phase of solar f and p-modes. More recently, Time-Distance and other local helioseismic techniques have been used to probe active regions by exploring phase shifts which are interpreted as travel-time perturbations. Although absorption is an intrinsically magnetic effect, phase shifts may be produced by both thermal and magnetic effects (and of course flows, though these can be factored out by averaging travel times in opposite directions). We will show how these two effects alter wave phase, and conclude that phase shifts in umbrae are predominantly thermal, whilst those in highly inclined field characteristic of penumbrae are essentially magnetic. The two effects are generally not additive.
Eight-state supersymmetric U model of strongly correlated fermions

An integrable eight-state supersymmetric U model is proposed, which is a fermion model with correlated single-particle and pair hoppings as well as uncorrelated triple-particle hopping. It has a gl(3/1) supersymmetry and contains one symmetry-preserving free parameter. The model is solved and the Bethe ansatz equations are obtained. [S0163-1829(98)00616-X].
The HELLAS2XMM Survey. I. The X-Ray Data and the log N-log S Relation

We present the first results from an XMM-Newton serendipitous medium-deep survey, which covers nearly 3 deg2. We detect a total of 1022, 495, and 100 sources, down to minimum fluxes of about 5.9 × 10-16, 2.8 × 10-15, and 6.2 × 10-15 ergs cm-2 s-1, in the 0.5-2, 2-10, and 4.5-10 keV bands, respectively. In the soft band this is one of the largest samples available to date and surely the largest in the 2-10 keV band at our limiting X-ray flux. The measured log N- log S determinations are found to be in good agreement with previous determinations. In the 0.5-2 keV band, we detect a break at fluxes around 5 × 10-15 ergs cm-2 s-1. In the harder bands, we fill in the gap at intermediate fluxes between deeper Chandra and XMM-Newton observations and shallower BeppoSAX and ASCA surveys.
Strain-induced polar discontinuities in two-dimensional materials from combined first-principles and Schrödinger-Poisson simulations

The local application of mechanical stress in piezoelectric materials gives rise to boundaries across which the electric polarization changes. Polarization charges appear along such polar discontinuities and the ensuing electric fields drive a charge reconstruction with the accumulation of free carriers at the boundaries. This is particularly relevant for two-dimensional materials that can sustain very large strains and display record piezoelectric responses. Here we show by first-principles simulations the emergence of one-dimensional wires of free electrons and holes along strain interfaces, taking SnSe as a paradigmatic material. We complement this by developing a Schr\"odinger-Poisson approach specifically designed for two-dimensional materials that is able to reproduce the ab initio results and also to extend them to regimes of parameters and system sizes that would be unaffordable in first-principles calculations. This model allows us to assess the degree of tunability for the free charge in the wires coming from strain values and profiles, and to obtain the critical size at which the interfaces start to be metallic.
Activation of Interferon-Stimulated Genes following Varicella-Zoster Virus Infection in a Human iPSC-Derived Neuronal In Vitro Model Depends on Exogenous Interferon-α

Varicella-zoster virus (VZV) infection of neuronal cells and the activation of cell-intrinsic antiviral responses upon infection are still poorly understood mainly due to the scarcity of suitable human in vitro models that are available to study VZV. We developed a compartmentalized human-induced pluripotent stem cell (hiPSC)-derived neuronal culture model that allows axonal VZV infection of the neurons, thereby mimicking the natural route of infection. Using this model, we showed that hiPSC-neurons do not mount an effective interferon-mediated antiviral response following VZV infection. Indeed, in contrast to infection with Sendai virus, VZV infection of the hiPSC-neurons does not result in the upregulation of interferon-stimulated genes (ISGs) that have direct antiviral functions. Furthermore, the hiPSC-neurons do not produce interferon-α (IFNα), a major cytokine that is involved in the innate antiviral response, even upon its stimulation with strong synthetic inducers. In contrast, we showed that exogenous IFNα effectively limits VZV spread in the neuronal cell body compartment and demonstrated that ISGs are efficiently upregulated in these VZV-infected neuronal cultures that are treated with IFNα. Thus, whereas the cultured hiPSC neurons seem to be poor IFNα producers, they are good IFNα responders. This could suggest an important role for other cells such as satellite glial cells or macrophages to produce IFNα for VZV infection control.
Detection of Sub-TeV Gamma Rays from the Galactic Center Direction by CANGAROO-II

We have detected sub-TeV gamma-ray emission from the direction of the Galactic center (GC) using the CANGAROO-II Imaging Atmospheric Cerenkov Telescope. We detected a statistically significant excess at energies greater than 250 GeV. The flux was 1 order of magnitude lower than that of the Crab Nebula at 1 TeV with a soft spectrum proportional to E-4.6±0.5. The signal centroid is consistent with the GC direction, and the observed profile is consistent with a pointlike source. Our data suggest that the GeV source 3EG J1746-2851 is identical to this TeV source, and we study the combined spectra to determine the possible origin of the gamma-ray emission. We also obtain an upper limit on the cold dark matter density in the Galactic halo.
Non-thermal phenomena in galaxy clusters

The discovery of diffuse synchrotron radio emission and, more recently, of the hard X-ray (HXR) tails have triggered a growing interest about non-thermal phenomena in galaxy clusters. After a brief review of the most important evidences for non-thermal emission, I will focus on the origin of the emitting particles and of the hadronic component. In particular I will describe the particle-injection and -acceleration mechanisms at work in the intra-cluster medium (ICM) and, at the same time, discuss the possibility to test current modellings of these phenomena with future radio, HXR, and gamma ray observatories.To search for other articles by the author(s) go to: http://adsabs.harvard. edu/abstract_service. html
Time-varying state feedback and output injection: duality and distinctions

The classical results on the duality of controllability and observability of linear systems are very well known and deeply analyzed in both cases of time invariant and time-varying linear systems. However the significant difference appears in the important properties of the responses in the problems of stabilization by state feedback (controller) and by output injection (observer) even in cases when only the gains become time-varying. Namely, it is possible to design a time-varying observer with fast decaying error almost without peaking (or equivalently to stabilize the system by output injection providing a fast decay without large deviations). But it is impossible to get the analogous result by using state feedback due to indispensable connection of fast decaying and large peaking. This difference is the main topic of the article and as a motivation for our interest we emphasize that the results of stabilization obtainable by output injection and by state feedback seem to be dual.
Multiple Cell Upset Partitioning for Simulation of Soft Error Rates in Space Systems with Error Correcting Codes

 Abstract — A self-consistent procedure for the ion-induced soft error rate calculation in space environment taking into account Error Correcting Codes is proposed. The method is based on the partitioning of the multiple cell events into groups with different multiplicities. The proposed partitioning method has been validated for the ground and on-orbit literature data.
The Young Stellar Population in M17 Revealed by Chandra

We report here results from a Chandra ACIS observation of the stellar populations in and around the M17 H II region. The field reveals 886 sources with observed X-ray luminosities (uncorrected for absorption) between ~ 29.3 ergs s-1 < log LX < 32.8 ergs s-1, 771 of which have stellar counterparts in infrared images. In addition to comprehensive tables of X-ray source properties, several results are presented:
Supersymmetric Rotating Black Holes and Causality Violation

The geodesics of the rotating extreme black hole in ﬁve spacetime dimensions found by Breckenridge, Myers, Peet and Vafa are Liouville integrable and may be integrated by additively separating the Hamilton-Jacobi equation. This allows us to obtain the St¨ackel-Killing tensor. We use these facts to give the maximal analytic extension of the spacetime and discuss some aspects of its causal structure. In particular, we exhibit a ‘repulson’-like behaviour occuring when there are naked closed timelike curves. In this case we ﬁnd that the spacetime is geodesically complete (with respect to causal geodesics) and free of singularities. When a partial Cauchy surface exists, we show, by solving the Klein-Gordon equation, that the absorption cross-section for massless waves at small frequencies is given by the area of the hole. At high frequencies a dependence on the angular quantum numbers of the wave develops. We comment on some aspects of ‘inertial time travel’ and argue that such time machines cannot be constructed by spinning up a black hole with no naked closed timelike curves.
An efficient block-circulant preconditioner for simulating fracture using large fuse networks*

Critical slowing down associated with the iterative solvers close to the critical point often hinders large-scale numerical simulation of fracture using discrete lattice networks. This paper presents a block-circulant preconditioner for iterative solvers for the simulation of progressive fracture in disordered, quasi-brittle materials using large discrete lattice networks. The average computational cost of the present algorithm per iteration is O(rslog s) + delops, where the stiffness matrix A is partitioned into r × r blocks such that each block is an s × s matrix, and delops represents the operational count associated with solving a block-diagonal matrix with r × r dense matrix blocks. This algorithm using the block-circulant preconditioner is faster than the Fourier accelerated preconditioned conjugate gradient algorithm, and alleviates the critical slowing down that is especially severe close to the critical point. Numerical results using random resistor networks substantiate the efficiency of the present algorithm.
Multifractal Scaling in the Bak-Tang-Wiesenfeld Sandpile and Edge Events

A widely applicable analysis of numerical data shows that, while the distribution of avalanche areas obeys finite size scaling, that of toppling numbers is universally characterized by a full, nonlinear multifractal spectrum. Boundary effects determine an unusual dependence on system size of the moment scaling exponents of the conditional toppling distribution at a given area. This distribution is also multifractal in the bulk regime. The resulting picture brings to light unsuspected physics of this long-studied prototype model.