Miracle-dz/UniFAR-FTUs huggingface dataset:
Multi-colour optical variability of the blazar 3C 454.3 in 2007-2010

Context. We present our optical multiband (B and R) observations of the blazar 3C 454.3, which were acquired over 30 nights from August 2007 to December 2010. Aims. We analyse our data to study the optical emission variability properties of 3C 454.3. Methods. The observations were carried out using both the 1 m EOS Telescope (EST) and the 0.8 m Tsinghua-NAOC Telescope (TNT) simultaneously in most nights at the Xinglong Observatory of National Astronomical Observatories, Chinese Academy of Sciences (NAOC). Both telescopes are equipped with the same type of Princeton Instrument CCD and standard Johnson-Cousin UBVRI filters. To reach a similar signal-to-noise ratio (S/N) in different bands with the same exposure time, observations using the larger diameter EST were carried out with B-band filter, while those of the smaller diameter TNT were carried out with R-band filter. Any time differences between the two telescopes were corrected using GPS. The typical sampling rate was one data point per minute, which is the highest time-resolution so far. Results. A multi-peak outburst was observed during November‐December 2007, in addition to a later outburst during October 27‐November 1, 2010. The brightest magnitudes for 3C 454.3 during our observations were B = 13.77 mag and R = 12.69 mag at JD =2454436.0952 (December 1, 2007). One of the most striking events was detected on December 1, 2007, when a flux increase of about 0.67 mag occurred in 3.2 h. A colour analysis shows that the colour variability processes are apparently complex. A bluer-when-brighter trend, a redder-when-brighter trend (generally in faint states), and no significant colour variance were all detected during the outburst of November‐December 2007. Furthermore, the kind of “saturation” effect in the B − R trend is not visible in the bright state (R < 14) during August 12‐14, 2007. These trends may be due to the interactive contribution from the accretion disc and the jet components. Meanwhile, intra-night variability in B and R bands was found to be correlated, without any time delay exceeding one minute.
General Relativistic Magnetohydrodynamic Simulations of Jets from Black Hole Accretion Disks: Two-Component Jets Driven by Nonsteady Accretion of Magnetized Disks

The radio observations have revealed the compelling evidence of the existence of relativistic jets not only from active galactic nuclei but also from "microquasars" in our Galaxy. In the cores of these objects, it is believed that a black hole exists and that violent phenomena occur in the black hole magnetosphere, forming the relativistic jets. To simulate the jet formation in the magnetosphere, we have newly developed the general relativistic magnetohydrodynamic code. Using the code, we present a model of these relativistic jets, in which magnetic fields penetrating the accretion disk around a black hole play a fundamental role of inducing nonsteady accretion and ejection of plasmas. According to our simulations, a jet is ejected from a close vicinity to a black hole (inside 3rS, where rS is the Schwarzschild radius) at a maximum speed of ~90% of the light velocity (i.e., a Lorentz factor of ~2). The jet has a two-layered shell structure consisting of a fast gas pressure-driven jet in the inner part and a slow magnetically driven jet in the outer part, both of which are collimated by the global poloidal magnetic field penetrating the disk. The former jet is a result of a strong pressure increase due to shock formation in the disk through fast accretion flow ("advection-dominated disk") inside 3rS, which has never been seen in the nonrelativistic calculations.
Single Cavity Trapped Vortex Combustor Dynamics – Part-2: Simulations

The first part described a versatile TVC test rig capable of a continuously variable length-to-depth ratio (L/D) of the cavity and optical access through quartz plates provided on three sides for visualization. Flame stabilization in the single cavity TVC was successfully achieved with methane as fuel and the range of flow conditions for stable operation were identified. From these, a few cases were selected for detailed experimentation, the results of which were presented in part-1. The results indicated that reducing L/D ratio and increasing cavity-air velocity favour stable combustion. In the present paper, numerical simulations are performed to ascertain reasons for some of the trends. The predicted temperatures at the exit showed reasonably good agreement with measured values. The experiments are also performed for different flow conditions to ascertain stability limits of the combustor. Insight from these set of experiments along with simulations has highlighted the importance of air and fuel injection strategies in the cavity. It was observed in the experiments that for certain cases involving moderate cavity-air velocity, the flame tend to blowout whereas at higher and lower cavity-air velocities, the flame was observed to be stable. This observation could be explained based on understanding obtained from simulations. From a mixing and combustion efficiency standpoint, it is desirable to have a cavity vortex that is anti-clockwise. However, natural tendency for flow over a cavity is to form a vortex that is clockwise. The tendency to blowout at higher inlet flow velocities is thought to be because of these two opposing effects. This basic understating of cavity flow dynamics can be used for further design improvements in future to improve flame stability at higher inlet flow velocities.
Instability and blow-up of solutions to a generalized Boussinesq equation

In this paper we investigate conditions for the finite-time blow-up of solutions of the generalized Boussinesq equation (BQ) \[ u_{tt} - u_{xx} + (f(u) + u_{xx} )_{xx} = 0,\quad x \in {\bf R},t > 0. \] The conditions are expressed in terms of the energy of the ground state. In particular, there exist initial data arbitrarily close to the stationary state of lowest energy whose solutions blow up in finite time.
Emission-Line Diagnostics of T Tauri Magnetospheric Accretion. I. Line Profile Observations

We present high-resolution spectra of classical T Tauri stars in Taurus in the range 5800–9000 Å to critically examine the current theories of magnetospheric accretion. In this paper, we focus on the emission lines of hydrogen (the higher Paschen series and Hα), He I λ5876, O I λ7773 and λ8446, the Na D lines, and the Ca II infrared triplet. We argue that the magnetospheric infall zone is the likely source of emission for the hydrogen, oxygen, and sodium lines for most of the stars in our sample. As has been previously shown, the calcium and helium lines have a narrow and a broad component; focusing on the broad components, we find that they are likely formed in the magnetosphere for at least several of the stars in the sample. Preliminary calculations indicate that the magnetospheric models developed to explain the Balmer lines predict significant Ca II, Paschen, and O I emission, roughly comparable to what is observed. However, in some of the stars, especially at high veilings, the case for line formation in the accretion flow is not clear. Finally, our results suggest that the Ca II IR triplet lines are good indicators of the accretion rate for all but the most weakly accreting T Tauri stars.
Convergence of blow-up solutions of nonlinear heat equations in the supercritical case

In this paper, we study the blow-up behaviour of the radially symmetric non-negative solutions u of the semilinear heat equation with supercritical power nonlinearity up (that is, (N – 2)p> N + 2). We prove the existence of non-trivial self-similar blow-up patterns of u around the blow-up point x = 0. This result follows from a convergence theorem for a nonlinear parabolic equation associated to the initial one after rescaling by similarity variables.
A NONPARAMETRIC REGRESSION ESTIMATOR THAT ADAPTS TO ERROR DISTRIBUTION OF UNKNOWN FORM

We propose a new kernel estimator for nonparametric regression with unknown error distribution. We show that the proposed estimator is adaptive in the sense that it is asymptotically equivalent to the infeasible local likelihood estimator (Staniswalis, 1989, Journal of the American Statistical Association 84, 276–283; Fan, Farmen, and Gijbels, 1998, Journal of the Royal Statistical Society, Series B 60, 591–608; and Fan and Chen, 1999, Journal of the Royal Statistical Society, Series B 61, 927–943), which requires knowledge of the error distribution. Hence, our estimator improves on standard nonparametric kernel estimators when the error distribution is not normal. A Monte Carlo experiment is conducted to investigate the finite-sample performance of our procedure.We thank Yuichi Kitamura, Yanqin Fan, Joel Horowitz, Roger Koenker, Jens Perch Nielsen, Peter Phillips, Peter Robinson, Tom Rothenberg, and two referees for helpful comments. Financial support from the NSF and the ESRC (UK) is gratefully acknowledged.
Electromagnetic characteristics of Polyaniline/SWCNT composites

Electromagnetic field interactions with the composites made up of polyaniline (PANI) and single wall carbon nanotube (SWCNT) are simulated using the discrete dipole approximation. Recent observations on polymer nano-composites explain the interface interactions between the PANI host and the carbon nanostructures. These types of composite have potential applications in organic solar cell, gas sensor, bio-sensor and electro-chromic devices. Various nanostructures of PANI is possible in the form of nanowires, nanodisks, nanofibers and nanotubes have been reported. In the present study, we considered two types of composite, one is the PANI wrapped CNT and the other is CNT immersed in PANI nanotube. We use Modified Thole’s parameters for calculating frequency dependent atomic polarizability of composites. Absorption spectra of the composites are studied by illuminating a wide range of electromagnetic energy spectrum. From the absorption spectra, we observe plasmon excitation in near-infrared region similar to that in SWCNTs reported recently. The interactions between the PANI and CNT in the composite, resulting electromagnetic absorptions are simulated.
Cofactors and markers of disease progression in human immunodeficiency virus infection

The identification of factors which are related to human immunodeficiency virus (HIV) disease progression, either by a direct interaction with HIV to increase the rate of disease progression or by providing an indication of an infected individual's likely prognosis, can have great value when understanding HIV pathogenesis and in the development of novel therapeutic approaches. This paper describes the roles of the CD4 cell count and the viral load as markers of disease progression and discusses the recent findings on chemokine receptors in HIV infection. Our current knowledge on these factors is summarized and unresolved statistical issues are highlighted.
Portable Raman Lidar Polly XT for Automated Profiling of Aerosol Backscatter, Extinction, and Depolarization

Two versions of the portable aerosol Raman lidar system (Polly) are presented. First, the two-channel prototype is depicted. It has been developed for the independent and simultaneous determination of particle backscatter and extinction coefficient profiles at 532 nm. Second, the 3 1 2 Raman lidar Polly XT (3 1 2: three backscatter and two extinction coefficients), the second generation of Polly, is described. The extended capabilities of Polly XT are due to the simultaneous emission of light with three wavelengths, more laser power, a larger main receiver mirror, and seven receiver channels. These systems are completely remotely controlled and all measurements are performed automatically. The collected data are transferred to a home server via the Internet and are displayed on a Web page. This paper describes the details of the optical setup, the housekeeping of the systems, and the used data retrieval routines. A measurement example taken close to Manaus, Brazil, on 15 August 2008 shows the capabilities of Polly XT .
Size Distribution of Faint Jovian L4 Trojan Asteroids

We detected 51 faint Jovian Trojan asteroids in the L4 Lagrangian swarm in survey observations near opposition and the ecliptic using a wide-field mosaicked CCD camera on the 8.2 m Subaru Telescope. We report the Trojan size distributions in this paper. The surveyed sky area was about 3 deg2 and located ∼30° in longitude ahead of the L4 point. From trailed-image simulations of hypothetical Trojans, we measured the 90% complete detection limiting magnitudes for our Trojan asteroids on a CCD chip-by-chip basis. The limiting magnitudes varied by 0.4–0.5 mag between chips; therefore, we introduce a new measure of detection limit appropriate for multichip CCD cameras. By statistically comparing the observed number of Trojans with the predictions from theoretical size distributions near the limiting magnitude calculated in this way, we determined a limiting diameter of D ∼ 2 km, corresponding to the detection limit of this survey. On the other hand, the detected Trojans covered a size range of 0.7 km < D < 12.3 km (with an assumed albedo of 0.04 for each object, which is the mean value of known Trojans thus far). Hence, we discuss the size distribution of the observed Trojans in the size range of 2 km < D < 10 km. For this entire range, we found the mean slope of the cumulative size distribution, namely, the power-law distribution index, to be 1.9 ± 0.1; this value is consistent with the 2000 estimate by Jewitt and coworkers. However, we noted a slight change in the slope of the cumulative size distribution at D ∼ 5 km. Therefore, we obtained separately fitted slopes for the size ranges of 2 km ≤ D < 5 km and 5 km < D ≤ 10 km of 1.3 ± 0.1 and 2.4 ± 0.1, respectively. This break in the slope of the size distribution has also been seen in the size distribution of kilometer to subkilometer main-belt asteroids (Yoshida and coworkers), and so we compared the size distributions of the two populations. Based on the surface distribution model of L4 Trojans proposed by Jewitt and coworkers, we estimated the total number of L4 Trojans with D > 1 km. Finally, we discuss, from a cosmogonic viewpoint, a possible relation between Trojans and short-period comets on the basis of their size distribution slopes.
Water vapour variability induced by urban/rural surface heterogeneities during convective conditions

Scientific interest in urban meteorology has increased because highly populated areas experience high vulnerability to pollution or heavy rain. However, compared to urban air quality or urban heat island (UHI) processes, the urban water vapour cycle is poorly understood because it has been investigated less due to the lack of upper‐air measurements and the high sensitivity of surface measurements to local heterogeneities. In this paper, surface measurements of wind, temperature, pressure and humidity, as well as integrated water vapour (IWV) from GPS and MODIS and numerical simulations, have been used to investigate the urban cycle of water vapour in May and June 2004 during the VAPIC field experiment in the Paris area.
Domain-irrelevant Feature Learning for Generalizable Pan-sharpening

Pan-sharpening aims to spatially enhance the low-resolution multispectral image (LRMS) by transferring high-frequency details from a panchromatic image (PAN) while preserving the spectral characteristics of LRMS. Previous arts mainly focus on how to learn a high-resolution multispectral image (HRMS) on the i.i. d. assumption. However, the distribution of training and testing data often encounters significant shifts in different satellites. To this end, this paper proposes a generalizable pan-sharpening network via domain-irrelevant feature learning. On the one hand, a structural preservation module (STP) is designed to fuse high-frequency information of PAN and LRMS. Our STP is performed on the gradient domain because it consists of structure and texture details that can generalize well on different satellites. On the other hand, to avoid spectral distortion while promoting the generalization ability, a spectral preservation module (SPP) is developed. The key design of SPP is to learn a phase fusion network of PAN and LRMS. The amplitude of LRMS, which contains 'satellite style' information is directly injected in different fusion stages. Extensive experiments have demonstrated the effectiveness of our method against state-of-the-art methods in both single-satellite and cross-satellite scenarios. Code is available at: https://github.com/LYL1015/DIRFL.
One-dimensional linear analysis of the compound jet

The stability of an infinitely long compound liquid column is analysed by using a one-dimensional inviscid slice model. Results obtained from this one-dimensional linear analysis are applicable to the study of compound capillary jets, which are used in the ink-jet printing technique. Stability limits and the breaking regimes of such fluid configurations are established, and, whenever possible, theoretical results are compared with experimental ones.
Static output feedback control for switched systems

We investigate the design of a static output feedback control for switching discrete time systems. Looking at the problem of stability analysis, we give two conditions allowing to check the existence of a particular class of Lyapunov functions. Although one can recover the first condition as a particular case from the second one, it is proved that the two conditions are equivalent for stability analysis. Then we show that when one is faced with a static output feedback control problem, the second condition leads to a sufficient solution to build a stabilizing static output feedback controller which is less conservative than the solution based on the first condition.
Effects of Peripheral Visual and Physical Motion Cues in Roll-Axis Tracking Tasks

In this paper, the effects of peripheral visual and physical motion cues on manual control of second-order roll dynamics are investigated. In particular, the differences between the use of these cues in compensatory target-following and disturbance-rejection tasks are considered. Tracking performance, control activity, and measures of control behavior are determined from recent measurements and compared with results from an earlier experiment. Most previously reported effects of peripheral visual and physical motion cues in target following and disturbance rejection are confirmed. A comparison of tasks with varying levels of difficulty is found to reveal reduced effectiveness of peripheral visual and physical motion cues in the less difficult target-following tasks only. Observed differences in measured control behavior for target following and disturbance rejection are related to effective strategies for reducing tracking errors introduced by the forcing-function signals in both tasks.
A Dynamical Downscaling Case Study for Typhoons in Southeast Asia Using a Regional Climate Model

Abstract This study explores the possibility of reconstructing the weather of Southeast Asia for the last decades using an atmospheric regional climate model, the Climate version of the Lokal-Modell (CLM). For this purpose global National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalyses data were dynamically downscaled to 50 km and in a double-nesting approach to 18-km grid distance. To prevent the regional model from deviating significantly from the reanalyses with respect to large-scale circulation and large-scale weather phenomena, a spectral nudging technique was used. The performance of this technique in dealing with Southeast Asian typhoons is now examined by considering an ensemble of one simulated typhoon case. This analysis is new insofar as it deals with simulations done in the climate mode (so that any skill of reproducing the typhoon is not related to details of initial conditions), is done in ensemble mode (the same development is described .
Spectroscopic observations of unbound asteroid pairs using the WHT

Recently over 62 pairs of asteroids have been shown to have very similar orbital elements. Backward integration of their orbits indicates that the asteroids in each pair likely had very close encounters at low relative velocities, consistent with models of the spin-up and rotational fission of asteroids. Although linked dynamically, the observation of highly similar spectra would suggest that the asteroids share a common composition, which we would expect if they formed from a common parent body. We have begun an observational campaign whose aim is to obtain optical and/or NIR spectra of a large sample of these unbound asteroid pairs to determine whether the asteroids in each pair exhibit similar spectra. We present optical spectroscopic observations of four complete pairs obtained using the William Herschel Telescope. We find that the components of pairs 1979-13732 and 19289-278067 share very similar spectra and likely have a common origin. Our current spectra of 17198-229056 are sufficiently different to suggest that they do not have a common origin, although this is contrary to the strong dynamical linkup of these asteroids demonstrated in the current paper and previous studies. Further observations of this pair are encouraged to examine why the spectra are so different. It is unclear whether the spectra of the final pair, 11842-228747, are a match due to the low S/N of the secondary's spectrum. We discuss the process of space weathering and present new dynamical analyses which confirm the previously estimated ages of the observed pairs. The time-scale for space weathering appears to be longer than 1 Myr for at least some pairs. We also present an efficient method which can be used to determine the positional convergence of unbound asteroid pairs.
Hume = Small Hume

Here, X and Y are understood as classes, or concepts, or higher-order entities which are not first-order objects, and the formula X Y expresses, in the dyadic second-order language, the equinumerosity of X and Y. The first-order entity #X is the cardinal number associated with X. This axiom is sometimes called Hume’s Principle and the formal system obtained by adding (Hume) to the second-order logic is called Frege Arithmetic. Discussing Wright’s work, Burgess (1984), Hodes (1984) and Hazen (1985) noted that Frege Arithmetic has a (countable) model, and it was subsequently verified (by Boolos 1986/7, 1987, and others) that second-order arithmetic Z2 is interpretable within Frege Arithmetic. In 1989 Boolos proposed a weakened modification of Basic Law V,
Comparison of radiative properties of InAs quantum dots and GaInNAs quantum wells emitting around 1.3 μm

The emission properties of self-assembled InAs quantum dots (QDs) and lattice-matched GaInNAs quantum wells (QWs) emitting around 1.3 μm were investigated by temperature-dependent and time-resolved photoluminescence (PL). The QDs have much higher PL efficiency at low excitation, but saturate faster as the excitation is increased, due to the lower density of states. Lifetime measurements show that nonradiative recombination plays a more important role in the GaInNAs QW than in QDs.
Linearly independent, orthogonal and equivariant immersions

In this article we define the notions of linearly independent and orthogonal immersions and introduce the notion of adjoint hyperquadrics of linearly independent immersions. We investigate the relations between linearly indedendent immersions, orthogonal immersions, equivariant immersions and adjoint hyperquadrics. Several results in this respect are obtained.
Observation and investigation of vacuum arc under various distributed axial magnetic fields

The vacuum arc under various distributed axial magnetic fields (AMF) is observed by a high speed charged coupled devices camera. Through the images, the influence of AMF distribution on vacuum arc behavior is investigated. The result shows that a proper nonuniform distributed AMF can control the vacuum arc to distribute more uniformly on the contacts and it could be helpful for finding a more effective AMF distribution.