Miracle-dz/UniFAR-FTUs huggingface dataset:
Intense accretion and mass loss of a very low mass young stellar object

We present visible and near-infrared photometry and spectroscopy of LS-RCrA 1, a faint, very late-type object (M 6.5-M 7) seen in the direction of the R Coronae Australis star forming complex. While its emission spectrum shows prominent features of accretion and mass loss typical of young stellar objects, its underlying continuum and photometric properties are puzzling when trying to derive a mass and age based on pre-main sequence evolutionary tracks: the object appears to be far too faint for a young member of the R Coronae Australis complex of its spectral type. We speculate that this may be due to either its evolution along pre-main sequence tracks being substantially altered by the intense accretion, or to a combination of partial blocking and scattering of the light of the object by a nearly edge-on circumstellar disk. The rich emission line spectrum superimposed on the stellar continuum is well explained by an intense accretion process: the H α , CaII infrared triplet, and HeI 6678 lines show equivalent widths typical of very active classical T Tauri stars. The near-infrared observations show anomalously weak spectral features and no significant excess emission in the K band, which we tentatively interpret as indicating line filling due to emission in a magnetic accretion funnel flow. At the same time, numerous, strong forbidden optical lines ([OI], [NII] and [SII]) and H 2 emission at 2.12 μ m suggest that the object is simultaneously undergoing mass loss, providing another example that shows that mass loss and accretion are closely related processes. Such an intense accretion and mass loss activity is observed for the first time in a young stellar object in the transition region between low mass stars and brown dwarfs, and provides a valuable observational test on the effects of accretion on the evolution of objects with such low masses.
Counting solutions of the Bethe equations of the quantum group invariant open XXZ chain at roots of unity

We consider the U q sl ( 2 ) ? > -invariant open spin-1/2 XXZ quantum spin chain of finite length N. For the case that q is a root of unity, we propose a formula for the number of admissible solutions of the Bethe ansatz equations in terms of dimensions of irreducible representations of the Temperley–Lieb algebra; and a formula for the degeneracies of the transfer matrix eigenvalues in terms of dimensions of tilting U q sl ( 2 ) ? > -modules. These formulas include corrections that appear if two or more tilting modules are spectrum-degenerate. For the XX case ( q = e i &pgr; / 2 ? > ), we give explicit formulas for the number of admissible solutions and degeneracies. We also consider the cases of generic q and the isotropic ( q → 1 ? > ) limit. Numerical solutions of the Bethe equations up to N = 8 are presented. Our results are consistent with the Bethe ansatz solution being complete.
Electrostatic properties of porcupic and bulbic spheroids

This contribution describes the effect of geometric and material properties on the electrostatic scattering from a spheroidal object. The object is assumed to be anisotropic in a way that aligns the axis of anisotropy with the unit vectors of the spheroidal coordinate system. It is further assumed that the object is immersed in a homogeneous background medium, which is permeated by a uniform and static electric field.
Response to “Articulation index predictions for hearing-impaired listeners with and without cochlear dead regions” [J. Acoust. Soc. Am. 111, 2545–2548 (2002)]

Rankovic [J. Acoust. Soc. Am. 111, 2545–2548 (2002)] argues that the AI, calculated according to Fletcher’s method, gives good predictions of speech intelligibility for subjects with high-frequency hearing loss listening to amplified speech, regardless of the presence or absence of dead regions. She suggests further that “…it seems premature to introduce a clinical test for identifying dead regions because it is not clear what information is gained beyond what is obtainable by calculating the AI. ” I argue that, in fact, the AI is not accurate in predicting the incremental benefit of amplifying frequencies well above the estimated edge frequency (Fe) of a dead region. For five out of nine cases, application of the AI leads to the prediction that amplification of frequencies well above Fe would improve speech scores by 10%–15%; in fact, the largest improvement was 7%.
Multiple positive solutions for Kirchhoff type problems involving concave and critical nonlinearities in ${R}^3$

In this paper, we consider the multiplicity of solutions for a class of Kirchhoff type problems with sub-linear and critical terms on an unbounded domain. With the aid of Ekeland's variational principle and the concentration compactness principle we prove that the Kirchhoff problem has at least two solutions.
Regularity of the conditional expectations with respect to signal to noise ratio

Let (W,H,μ) be the classical Wiener space, assume that Uλ = IW + uλ is an adapted perturbation of identity where the perturbation uλ is an H-valued map, defined up to μ-equivalence classes, such that its Lebesgue density s → u̇λ(s) is almost surely adapted to the canonical filtration of the Wiener space and depending measurably on a real parameter λ. Assuming some regularity for uλ, its Sobolev derivative and integrability of the divergence of the resolvent operator of its Sobolev derivative, we prove the almost sure and L-regularity w.r. to λ of the estimation E[u̇λ(s)|Uλ(s)] and more generally of the conditional expectations of the type E[F | Uλ(s)] for nice Wiener functionals, where (Uλ(s), s ∈ [0, 1]) is the the filtration which is generated by Uλ. These results are applied to prove the invertibility of the adapted perturbations of identity, hence to prove the strong existence and uniqueness of functional SDE’s; convexity of the entropy and the quadratic estimation error and finally to the information theory.
R**4 corrections to eleven dimensional supergravity via supersymmetry

By applying Noether method to N=1 local supersymmetry in eleven dimensions, we obtained two candidates of R^4 corrections to the supergravity. The bosonic parts of these two completely match with the results obtained by type IIA string perturbative calculations. We also obtained 13 parameters which relate only fermionic terms.
Biotechnologically Relevant Enzymes and Proteins

An intermolecular disulfide bond is required for thermostability and thermoactivity of β-glycosidase from Thermococcus kodakarensis KOD1 Abstract Scientists are interested in understanding the molecular origin of protein thermostability and thermoactivity for possible biotechnological applications. The enzymes from extremophilic organisms have been of particular interest in the last two decades. β-glycosidase, Tkβgly is a hyperther-mophilic enzyme from Thermococcus kodakarensis KOD1. Tkβgly contains two conserved cysteine residues, C88 and C376. The protein tertiary structure obtained through homol-ogy modeling suggests that the C88 residue is located on the surface whereas C376 is inside the protein. To study the role of these cysteine residues, we substituted C88 and C376 with serine residues through site-directed mutagenesis. The wild-type and C376S protein existed in dimeric form and C88S in monomeric form, in an SDS-PAGE gel under non-reducing conditions. Optimal temperature experiments revealed that the wild-type was active at 100 °C whereas the C88S mutant exhibited optimal activity at 70 °C. The half-life of the enzyme at 70 °C was drastically reduced from 266 h to less than 1 h. Although C88 was not present in the active site region, the k cat /K m of C88S was reduced by 2-fold. Based on the structural model and biochemical properties, we propose that C88 is crucial in maintaining the thermostability and thermoactivity of the Tkβgly enzyme.
Nilpotent orbits of exceptional Lie algebras over algebraically closed fields of bad characteristic

Abstract The classification of the nilpotent orbits in the Lie algebra of a reductive algebraic group (over an algebraically closed field) is given in all the cases where it was not previously known (E7 and E8 in bad characteristic, F4 in characteristic 3). The paper exploits the tight relation with the corresponding situation over a finite field. A computer is used to study this case for suitable choices of the finite field.
Destabilization of energetic particle modes by localized particle sources

In the present paper, in order to delineate the essential physics, analytic dispersion relations for Energetic Particle Modes (EPM) excitation via precessional resonance in toroidal systems are derived in various limiting but still relevant cases. The analytic dispersion relations obtained here can be readily applied to EPM excitations by magnetically trapped energetic ions generated with ion cyclotron frequency heating. It is also demonstrated that “frequency chirping” is what the linear dispersion relation of EPM’s predicts when the local properties of either energetic particles or the thermal plasma are changed. A new novel result is that, for sufficiently strong spatial gradients, energetic particles can produce an effective potential well that radially (globally) traps the EPM. This property is a crucial and peculiar one of EPM’s, and it could have important implications to the self-consistent nonlinear dynamic evolution of the fast particle distribution.
Effects of growth conditions on the incorporation of oxygen in AlGaN layers grown by plasma assisted molecular beam epitaxy

Using secondary ion mass spectroscopy we have shown that oxygen incorporation in AlGaN films is dependent upon the III/V growth conditions and the growth temperature of the films. AlGaN films grown under excess group III conditions (Ga-rich) exhibited step flow growth and at least a factor of 3 less oxygen incorporation than films grown under excess group V (N-rich conditions). We found that oxygen incorporation into AlGaN decreases as the growth temperature is increased. The lowest oxygen levels were achieved by growing at 750 °C under Ga-rich growth conditions. Possible sources of unwanted oxygen are discussed.
Four ways across the wall

An important question in the study of 𝒩 = 2 supersymmetric string or field theories is to compute the jump of the BPS spectrum across walls of marginal stability in the space of parameters or vacua. I survey four apparently different answers for this problem, two of which are based on the mathematics of generalized Donaldson-Thomas invariants (the Kontsevich-Soibelman and the Joyce-Song formulae), while the other two are based on the physics of multi-centered black hole solutions (the Coulomb branch and the Higgs branch formulae, discovered in joint work with Jan Manschot and Ashoke Sen [1]). Explicit computations indicate that these formulae are equivalent, though a combinatorial proof is currently lacking.
An anisotropic diffusion filter for ultrasonic speckle reduction

Anisotropic diffusion has been widely used to reduce speckle noise from ultrasound images. However, in traditional anisotropic diffusion methods, usually four directions neighborhood are used, which have many disadvantages, such as the sensitivity to the noise, the loss of image details and false contours. In this paper, we modify the standard SRAD (speckle reducing anisotropic diffusion) algorithm in the discrete domain by considering larger neighborhoods in its computation; then we adopt a confine term to keep the closest equivalence between the filtered image and the original image. Experimental results show that, in the presence of speckle nose, this proposed method could effectively preserve edges and detailed structures while suppressing speckle noise These preliminary results indicate that the proposed speckle reduction method could improve image quality and the visibility of small structures and fine details in the medical ultrasound images.
Deflectometry challenges interferometry: the competition gets tougher!

Deflectometric methods that are capable of providing full-field topography data for specular freeform surfaces have been around for more than a decade. They have proven successful in various fields of application, such as the measurement of progressive power eyeglasses, painted car body panels, or windshields. However, up to now deflectometry has not been considered as a viable competitor to interferometry, especially for the qualification of optical components. The reason is that, despite the unparalleled local sensitivity provided by deflectometric methods, the global height accuracy attainable with this measurement technique used to be limited to several microns over a field of 100 mm. Moreover, spurious reflections at the rear surface of transparent objects could easily mess up the measured signal completely. Due to new calibration and evaluation procedures, this situation has changed lately. We will give a comparative assessment of the strengths and – now partly revised – weaknesses of both measurement principles from the current perspective. By presenting recent developments and measurement examples from different applications, we will show that deflectometry is now heading to become a serious competitor to interferometry.
The Important Role of Contextual Information in Speech Perception in Cochlear Implant Users and Its Consequences in Speech Tests

This study investigated the role of contextual information in speech intelligibility, the influence of verbal working memory on the use of contextual information, and the suitability of an ecologically valid sentence test containing contextual information, compared with a CNC (Consonant-Nucleus-Consonant) word test, in cochlear implant (CI) users. Speech intelligibility performance was assessed in 50 postlingual adult CI users on sentence lists and on CNC word lists. Results were compared with a normal-hearing (NH) group. The influence of contextual information was calculated from three different context models. Working memory capacity was measured with a Reading Span Test. CI recipients made significantly more use of contextual information in recognition of CNC words and sentences than NH listeners. Their use of contextual information in sentences was related to verbal working memory capacity but not to age, indicating that the ability to use context is dependent on cognitive abilities, regardless of age. The presence of context in sentences enhanced the sensitivity to differences in sensory bottom-up information but also increased the risk of a ceiling effect. A sentence test appeared to be suitable in CI users if word scoring is used and noise is added for the best performers.
On the non-equivalence of observables in phase-space reconstructions from recorded time series

In practical problems of phase-space reconstruction, it is usually the case that the reconstruction is much easier using a particular recorded scalar variable. This seems to contradict the general belief that all variables of a dynamical system are equivalent in phase-space reconstruction problems. This paper will argue that, in many cases, the choice of a particular scalar time series from which to reconstruct the original dynamics could be critical. It is argued that different dynamical variables do not provide the same level of information (observability) of the underlying dynamics and, as a consequence, the quality of a global reconstruction critically depends on the recorded variable. Examples in which the choice of observables is critical are discussed and the level of information contained in a given variable is quantified in the case where the original system is known. A clear example of such a situation arises in the R ¨ ossler system for which the performance of a global vector field reconstruction technique is investigated using time series of variables x, y or z, taken one at a time.
Model choice using reversible jump Markov chain Monte Carlo

We review the across‐model simulation approach to computation for Bayesian model determination, based on the reversible jump Markov chain Monte Carlo method. Advantages, difficulties and variations of the methods are discussed. We also discuss some limitations of the ideal Bayesian view of the model determination problem, for which no computational methods can provide a cure.
Testing the evolutionary constraints of metamorphosis: The ontogeny of head shape in Triturus newts

In vertebrates with complex, biphasic, life cycles, larvae have a distinct morphology and ecological preferences compared to metamorphosed juveniles and adults. In amphibians, abrupt and rapid metamorphic changes transform aquatic larvae to terrestrial juveniles. The main aim of this study is to test whether, relative to larval stages, metamorphosis (1) resets the pattern of variation between ontogenetic stages and species, (2) constrains intraspecific morphological variability, and (3) similar to the “hour‐glass” model reduces morphological disparity. We explore postembryonic ontogenetic trajectories of head shape (from hatching to completed metamorphosis) of two well‐defined, morphologically distinct Triturus newts species and their F1 hybrids. Variation in head shape is quantified and compared on two levels: dynamic (across ontogenetic stages) and static (at a particular stage). Our results show that the ontogenetic trajectories diverge early during development and continue to diverge throughout larval stages and metamorphosis. The high within‐group variance and the largest disparity level (between‐group variance) characterize the metamorphosed stage. Hence, our results indicate that metamorphosis does not canalize head shape variation generated during larval development and that metamorphosed phenotype is not more constrained relative to larval ones. Therefore, metamorphosis cannot be regarded as a developmental constraint, at least not for salamander head shape.
A multi-projection non-contact tomography setup for imaging arbitrary geometries

Optical imaging and tomography in tissues can facilitate the quantitative study of several important chromophores and fluorophores in-vivo. Due to this fact, there has been great interest in developing imaging systems offering quantitative information on the location and concentration of chromophores and fluorescent probes. However, most imaging systems currently used in reasearch make use of fiber technology for delivery and detection, which restricts the size ofthe photon collecting arrays leading to insufficient spatial sampling and field of view. To enable large data sets and full 3600angular measurements, we developed a novel imaging system that enables 3D imaging of fluorescent signals in bodies of arbitrary shapes in a non-contact geometry in combination with a 3D surface reconstruction algorithm. The system is appropriate for in-vivo small animal imaging of fluorescent probes. The system consists of a rotating sample holder and a lens coupled CCD camera in combination with a fiber coupled scanning device. The accuracy of the system in obtaining the surface reconstruction was measured to be in the order of 1μm.
Measuring student learning using initial and final concept test in an STEM course

Effective assessment is a cornerstone in measuring student learning in higher education. For a course in Numerical Methods, a concept test was used as an assessment tool to measure student learning and its improvement during the course. The concept test comprised 16 multiple choice questions and was given in the beginning and end of the class for three semesters. Hake's gain index, a measure of learning gains from pre- to post-tests, of 0.36 to 0.41 were recorded. The validity and reliability of the concept test was checked via standard measures such as Cronbach's alpha, content and criterion-related validity, item characteristic curves and difficulty and discrimination indices. The performance of various subgroups such as pre-requisite grades, transfer students, gender and age were also studied.
Echelle-mepsicron time-resolved spectroscopy of the dwarf nova SS Cygni

High dispersion time-resolved spectrograms of the dwarf nova SS Cygni, obtained with the Echelle-Mepsicron system, show double peaked emission lines with a complex profile. The intensity of the Hβ line appears to be modulated by the orbital period. Radial velocity measurements of the wings of Hβ and of the absorption line system of the late-type star yield semiamplitude values of Kem=101±6 km s−1 and Kab=151±7 km s−1, respectively. Radial velocity measurements of the blue and red peaks and of the central absorption of Hβ reveal a synchronous movement with the broad wings, although there is some evidence of a narrow component probably associated with a hot spot in the disk or a chromospheric emission line from the secondary star. The Hβ modulation, the double profile and recently discovered UBV light variations support an inclination angle i ∼50°. The masses of the primary are Mp=0.60 M⊙ and Ms=0.40 M⊙, respectively. A detailed analysis of the absorption lines reveals a spectral type of K2V.
Testing linear causality in mean when the number of estimated parameters is high

This paper investigates the problem of testing for linear Granger causality in mean when the number of parameters is high with the possible presence of nonlinear dynamics. Dependent innovations are taken into account by considering tests which asymptotic distributions is a weighted sum of chi-squares and tests with modified weight matrices. Wald, Lagrange Multiplier (LM) and Likelihood Ratio (LR) tests for linear causality in mean are studied. It is found that the LM tests based on restricted estimators significantly improve the analysis of linear Granger causality in mean relations when the dimension is high or when the autoregressive order is large. We also see that the tests based on a modified asymptotic distribution have a better control of the error of first kind when compared to the tests with modified statistic in finite samples. An application to international finance data is proposed to illustrate the robustness to the presence of nonlinearities of the studied tests.
Two-color photorefractive properties in near-stoichiometric lithium tantalate crystals

The two-color photorefractive properties in undoped as-grown near-stoichiometric lithium tantalate crystals were investigated, where a near-infrared laser and a cw ultraviolet beam were used for writing and gating, respectively. The key parameters in characterizing two-color photorefractive effect, light-induced absorption change, two-color sensitivity, refractive index change, readout characteristics, and dark decay were measured by changing intensities of gating and writing beams, wavelengths of gating and writing beams for the crystals with different near-stoichiometric crystal compositions, and proton concentrations. The results showed that there exists an optimal crystal composition of around 49.65% for both sensitivity and refractive index change together with moderate lifetime of small polarons. The achieved refractive index change was on the order of 10−4, and the obtained maximum sensitivity was 0.18 cm/J. The extrapolated lifetime of holograms at room temperature in the crystals without observab.