Miracle-dz/UniFAR-FTUs huggingface dataset:
Can lensed stars be regarded as pointlike for microlensing by MACHOs

We derive an analytical formula for the maginification of an extended source with constant surface brightness lensed by a point mass. We find that the magnification for an extended source is significantly different from that for a point source when the impact parameter is comparable to the source size. In particular, the peak magnification for an extended source can be larger or smaller than the peak magnification for a point source. The results are relevant to the short-duration (approximately day) and high-magnification events in the search of massive compact halo objects in the Galactic halo by microlensing.
Measuring normal and friction forces acting on individual fine particles

Interparticle and surface forces are of great importance in many fields of pure and applied science. We present an apparatus to measure the normal and friction forces acting between a particle (radius of 0.5–20 μm) and another solid surface. The apparatus is based on the principle of an atomic force microscope. For quantitative friction measurements we propose a method to determine the lateral spring constants of atomic force microscope cantilevers with attached spherical particles.
Ionized Magnesium: Interpretation and Interest in Atrial Fibrillation

Background: Magnesium (Mg) is often used to manage de novo atrial fibrillation (AF) in the emergency department (ED) and intensive care unit (ICU). Point of care measurement of ionized magnesium (iMg) allows a rapid identification of patients with impaired magnesium status, however, unlike ionized calcium, the interpretation of iMg is not entirely understood. Thus, we evaluated iMg reference values, correlation between iMg and plasmatic magnesium (pMg), and the impact of pH and albumin variations on iMg levels. Secondary objectives were to assess the incidence of hypomagnesemia in de novo AF. Methods: A total of 236 emergency department and intensive care unit patients with de novo AF, and 198 control patients were included. Reference values were determined in the control population. Correlation and concordance between iMg and pMg were studied using calcium (ionized and plasmatic) as a control in the whole study population. The impact of albumin and pH was assessed in the discordant iMg and pMg values. Lastly, we assessed the incidence of ionized hypomagnesemia (hypoMg) among de novo AF. Results: The reference range values established in our study for iMg were: 0.48–0.65 mmol/L (the manufacturers were: 0.45–0.60 mmol/L). A strong correlation was observed between pMg and iMg (r = 0.85), but, unlike for calcium values, there was no significant impact of pH and albumin in iMg/pMg interpretation. The incidence of hypoMg among de novo AF patients was 8.5% (12.7% using our ranges). When using our ranges, we found a significant link (p = 0.01) between hyopMg and hypokalemia. Conclusion: We highlight the need for more accurate reference range values of iMg. Furthermore, our results suggest that blood Mg content is not identical to that of calcium. The incidence of ionized hypomagnesemia among de novo AF patients in our study is 8.5%.
Integration of satellite and surface data using a radiative-convective oceanic boundary-layer model

Abstract A mixing-line boundary-layer model is used to retrieve cloud-top height from satellite-derived cloud-top temperature using 700-hPa National Meteorological Center (NMC) analyses and the Comprehensive Ocean and Atmosphere Data Set (COADS) surface data as supporting datasets. Results are compared with the fixed-lapse-rate method of retrieving boundary-layer depth from sea surface temperatures (SST) and cloud-top temperatures. A radiative-convective equilibrium boundary-layer model is used to retrieve boundary-layer structure given SST and surface wind, satellite cloud-top temperatures and cloud fraction, and the 700-hPa NMC thermodynamic analyses. Good agreement is found between the COADS data and the model solutions for low-level temperature and moisture. This suggests that equilibrium boundary-layer models may be of use over remote oceans in the retrieval of boundary-layer structure.
Comparison of Selected Methods for Modeling of Multi-State Disease Progression Processes: A Simulation Study

Prognostic studies are essential to understand the role of particular prognostic factors and, thus, improve prognosis. In most studies, disease progression trajectories of individual patients may end up with one of mutually exclusive endpoints or can involve a sequence of different events. One challenge in such studies concerns separating the effects of putative prognostic factors on these different endpoints and testing the differences between these effects. In this article, we systematically evaluate and compare, through simulations, the performance of three alternative multivariable regression approaches in analyzing competing risks and multiple-event longitudinal data. The three approaches are: (1) fitting separate event-specific Cox's proportional hazards models; (2) the extension of Cox's model to competing risks proposed by Lunn and McNeil; and (3) Markov multi-state model. The simulation design is based on a prognostic study of cancer progression, and several simulated scenarios help investigate different methodological issues relevant to the modeling of multiple-event processes of disease progression. The results highlight some practically important issues. Specifically, the decreased precision of the observed timing of intermediary (non fatal) events has a strong negative impact on the accuracy of regression coefficients estimated with either the Cox's or Lunn-McNeil models, while the Markov model appears to be quite robust, under the same circumstances. Furthermore, the tests based on both Markov and Lunn-McNeil models had similar power for detecting a difference between the effects of the same covariate on the hazards of two mutually exclusive events. The Markov approach yields also accurate Type I error rate and good empirical power for testing the hypothesis that the effect of a prognostic factor on changes after an intermediary event, which cannot be directly tested with the Lunn-McNeil method. Bootstrap-based standard errors improve the coverage rates for Markov model estimates. Overall, the results of our simulations validate Markov multi-state model for a wide range of data structures encountered in prognostic studies of disease progression, and may guide end users regarding the choice of model(s) most appropriate for their specific application.
Clinical Use of Gastric Antisecretory Drugs in Hospitalized Pediatric Patients

Antisecretory drugs are frequently used in the treatment of pediatric gastrointestinal disorders. This study was aimed to assess the prescribing patterns and the safety of ranitidine and proton pump inhibitors (PPIs) in a cohort of Italian pediatric patients. Children aged >1 month to <16 years that were admitted to our Pediatric Clinic between 2016 and 2018 were enrolled in this retrospective observational study. All data were obtained from medical records and a parent telephone questionnaire. The exclusion criteria included the use of antisecretory therapy at hospital admission, failure to collect the relevant clinical data, and failure to administer the questionnaire. This study included 461 subjects, who were divided into four age groups: <2 years, 2–5 years, 6–11 years, and ≥12 years. Ranitidine was prescribed in 396 (85.9%) patients, mainly for the acute treatment of gastrointestinal symptoms, and a PPI was given to 65 (14.1%) children to treat gastroesophageal reflux disease, gastritis/ulcer, or for gastroprotection. During the study period, the percentage of patients treated with ranitidine progressively increased, except in the 2–5-year age group. We observed eighty-seven adverse drug reactions (ADRs), 61 of which occurred in the ranitidine group and 26 in the PPI group. The most common ADR was constipation (n = 35), which occurred more frequently in children treated with PPIs and in the 6–11-year age group. Ranitidine was the most used antisecretory drug in all the age groups, especially for acute treatment. Conversely, PPIs were the drugs of choice for prolonged treatments. Further research should be focused on developing an effective and safer alternative to ranitidine.
CONTACT LINE STABILITY AND UNDERCOMPRESSIVE SHOCKS IN DRIVEN THIN FILM FLOW

We present new experimental results for films driven by a thermal gradient with an opposing gravitational force. When the gravitational effect becomes non-negligible, the advancing front produces a very large capillary ridge which shows a remarkable tendency to remain stable. This phenomenon can be explained by new mathematical results for a lubrication model of the experiment. The advancing front evolves into an “undercompressive” capillary shock structure which is stable to contact line perturbations, unlike typical capillary ridges in driven film flows. [S0031-9007(98)07868-5]
Direct Numerical Simulation of a Fully Developed Turbulent Channel Flow With Respect to the Reynolds Number Dependence

Direct numerical simulation (DNS) of a fully developed turbulent channel flow for various Reynolds numbers has been carried out to investigate the Reynolds number dependence. The Reynolds number is set to be Re τ = 180, 395, and 640, where Re τ is the Reynolds number based on the friction velocity and the channel half width. The computation has been executed with the use of the finite difference method. Various turbulence statistics such as turbulence intensities, vorticity fluctuations, Reynolds stresses, their budget terms, two-point correlation coefficients, and energy spectra are obtained and discussed. The present results are compared with the ones of the DNSs for the turbulent boundary layer and the plane turbulent Poiseuille flow and the experiments for the channel flow. The closure models are also tested using the present results for the dissipation rate of the Reynolds normal stresses. In addition, the instantaneous flow field is visualized in order to examine the Reynolds number dependence for the quasi-coherent structures such as the vortices and streaks
Spectral analysis of higher order differential operators with unbounded coefficients

Higher even order linear differential operators with unbounded coefficients are studied. For these operators the eigenvalues of the characteristic polynomials fall into distinct classes or clusters. Consequently the spectral properties, deficiency indices and spectra, of the underlying differential operators are superpositions of the contributions from the individual clusters. These results are based on a quantitative improvement of Levinson's Theorem. Our methods will also be applicable to other classes of linear differential operators.
1 + ε expansion for interacting fermions

We examine the $1+\ensuremath{\epsilon}$ expansion for interacting fermions. The only weak-coupling fixed point is the normal Fermi-liquid one with different domains of attraction for $\ensuremath{\epsilon}\ensuremath{\gtrless}0$. For $\ensuremath{\epsilon}g0$ the Cooper divergence dominates over the Peierls divergence, but for $\ensuremath{\epsilon}l0$ their roles are reversed. The two divergences balanced only at $d=1$ causing a line of fixed points. For $\ensuremath{\epsilon}g0$ and repulsive interactions the charge-density-wave instability requires explicit inclusion of the interchain interaction.
Influence of the Angle of Incidence on Sputtering Yields

Small metal spheres are bombarded by uniform Hg+ ion beams of low energy (125 to 800 ev). Comparison of shadow micrographs of the spheres before and after sputtering makes it possible to determine the influence of the angle of incidence on sputtering yields. Fe, Ta, and Mo showed a pronounced increase in yield at more oblique incidence of the ions while Au, Ag, and Pt showed this effect only slightly.
Ultracompact Dwarf Candidates in the Hydra Cluster

NGC 3311, the giant cD galaxy in the Hydra Cluster (A1060), has one of the largest globular cluster systems known. We describe new Gemini GMOS (g′, i′) photometry of the NGC 3311 field which reveals that the red, metal-rich side of its globular cluster population extends smoothly upward into the mass range associated with the new class of ultracompact dwarfs (UCDs). We identify 29 UCD candidates with estimated masses >6 × 106 M☉ and discuss their characteristics. This UCD-like sequence is the most well-defined one yet seen, and reinforces current ideas that the high-mass end of the globular cluster sequence merges continuously into the UCD sequence, which connects in turn to the E galaxy structural sequence.
Testing Dependent Correlation Coefficients via Structural Equation Modeling

Organizational researchers are sometimes interested in testing if independent or dependent correlation coefficients are equal. Olkin and Finn and Steiger proposed several statistical procedures to test dependent correlation coefficients in a single group, whereas meta-analytic procedures can be used to test independent correlation coefficients in two or more groups. Because computer programming is usually involved, applied researchers may find these procedures hard to implement, especially in testing the dependent correlation coefficients. This article suggests using a structural equation modeling (SEM) approach as a unified framework to test independent and dependent correlational hypotheses. To demonstrate the comparability among these approaches, examples and ad hoc simulation studies are used. Advantages of the SEM approach are also discussed.
Deactivation of Yb 3+ ions due to photodarkening

We carefully examined the fluorescence properties of Yb-doped fibers before and after pump-induced photodarkening (PD) and found a significant reduction of Yb3+ fluorescence intensity and lifetime due to the degradation process, obviously correlated with the measured PD loss. To explain these results, a non-radiative energy transfer from excited Yb3+ ions to the atomic defects (color centers) in close vicinity of the Yb3+ ions is suggested and discussed quantitatively as a function of PD loss generated in fibers with different Yb concentrations, by various pump powers or at different photodarkening states. All modifications of fluorescence properties proved to be reversed by thermal bleaching of the PD-induced color centers.
A Symbolic Dance: The Interplay Between Movement, Notation, and Mathematics on a Journey Toward Solving Equations

This article analyzes the use of the software Grid Algebra with a mixed ability class of 21 nine-to-ten-year-old students who worked with complex formal notation involving all four arithmetic operations. Unlike many other models to support learning, Grid Algebra has formal notation ever present and allows students to “look through” that notation and interpret it either in terms of physical journeys on a grid or in terms of mathematical operations. A dynamic fluidity was found between the formal notation, imagery of movements on a grid, and the process of mathematical operations. This fluidity is interpreted as a “dance” between these three. The significant way in which this dynamic took place reflects the scaffolding and fading offered by the software, which was crucial to the students’ fluency with formal notation well beyond what has been reported from students of that age.
Stability and orthonormality of multivariate refinable functions

This paper characterizes the stability and orthonormality of the shifts of a multidimensional $(M,c)$ refinable function $\phi $ in terms of the eigenvalues and eigenvectors of the transition operator $W_{c_{\rm au}}$ defined by the autocorrelation $c_{\rm au}$ of its refinement mask $c, $ where M is an arbitrary dilation matrix. Another consequence is that if the shifts of $\phi$ form a Riesz basis, then $W_{c_{\rm au}}$ has a unique eigenvector of eigenvalue $1 ,$ and all of its other eigenvalues lie inside the unit circle. The general theory is applied to two-dimensional nonseparable $(M,c)$ refinable functions whose masks are constructed from Daubechies' conjugate quadrature filters.
Improvement of SIMPLER Algorithm for Incompressible Flow on Collocated Grid System

In this article an Improved SIMPLER (CLEARER) algorithm is proposed to solve incompressible fluid flow and heat transfer problems. Numerical study shows with the CLEARER algorithm on a collocated grid, in the correction stage the velocities on the main nodes are overcorrected with the pressure correction, which lowers the convergence rate; hence a second relaxation factor is introduced to overcome this disadvantage. By setting this factor less than the underrelaxation factor for velocities, the convergence performance can be significantly enhanced; meanwhile, the robustness can also be increased. Four numerical examples with reliable solutions are computed to validate the CLEARER algorithm, and the results show that this algorithm can predict the numerical results accurately. Compared with the SIMPLER algorithm, CLEARER can enhance the convergence rate greatly, and in some cases it only needs as little as 17% of the iterations required by SIMPLER to reach the same convergence criterion.
Motion of relativistic particles in axially symmetric and perturbed magnetic fields in a tokamak

An extensive comparison is given between an analytical theory for the computations of particle orbits of relativistic runaway electrons [M. de Rover et al., Phys. Plasmas 3, 4468 (1996)], and numerical simulations. A new numerical scheme is used for the computer simulations of guiding center orbits. Furthermore, simulations of the full particle motion, including the gyration are performed to check the guiding center approximation. The behavior of drift surfaces and particle orbits in axially symmetric magnetic fields, as predicted in the companion paper are confirmed. This includes the smaller minor radius of a drift surface compared to a magnetic flux surface with identical rotational transform, and the decrease of the minor radius of a drift surface with increasing particle energy. Magnetic islands and drift islands appear when the axial symmetry of the magnetic field is broken by harmonic perturbations. In the numerical simulations the amplitudes of the perturbations have been chosen to increase toward.
ON THE AUTOMATIC DETERMINATION OF LIGHT-CURVE PARAMETERS FOR CEPHEID VARIABLES

A computerized algorithm for the automatic detection of Cepheid variables and for the estimation of their periods, amplitudes, and mean magnitudes from sparse data sets is presented. It is intended to be suitable for use in such programs as the measurement of Cepheid distances to external galaxies, for example with the Hubble Space Telescope. The reliability of the algorithm is tested by application to new photometric reductions of pre-repair HST images of the nearby Sdm galaxy IC 4182, with comparison to published analyses of the same data (Saha et al. 1994, ApJ, 425, 14).
Hyperbolic Stochastic Partial Differential Equations with Additive Fractional Brownian Sheet

Let be a fractional Brownian sheet with Hurst parameters H, H′ ≤ 1/2. We prove the existence and uniqueness of a strong solution for a class of hyperbolic stochastic partial differential equations with additive fractional Brownian sheet of the form , where b(ζ, x) is a Borel function satisfying some growth and monotonicity assumptions. We also prove the convergence of Euler's approximation scheme for this equation.
A Nonparametric Framework for Comparing Trends and Gaps Across Tests

Problems of scale typically arise when comparing test score trends, gaps, and gap trends across different tests. To overcome some of these difficulties, test score distributions on the same score scale can be represented by nonparametric graphs or statistics that are invariant under monotone scale transformations. This article motivates and then develops a framework for the comparison of these nonparametric trend, gap, and gap trend representations across tests. The connections between this framework and other nonparametric tools, including probability–probability (PP) plots, the Mann-Whitney U test, and the statistic known as P(Y > X), are highlighted. The author describes the advantages of this framework over scale-dependent trend and gap statistics and demonstrates applications of these nonparametric methods to frequently asked policy questions.
English dialect syntax in Word Grammar

The article focuses on inherent variability in syntax and the challenge that it presents for theories of language structure, using illustrative data from the Scottish town of Buckie (Smith, 2000). Inherent variability challenges a linguistic theory at three levels of theoretical adequacy: structural (Does the theory distinguish the relevant structures? ), contextual (Does it allow structures to be related directly to their social context? ), and behavioural (Does it allow an explanation for the observed frequencies? ). The article summarizes the relevant claims of Word Grammar and shows (1) that it has at least as much structural adequacy as any other theory, (2) that it has more contextual adequacy than other theories because it formalizes the theory of Acts of Identity, and (3) that it at least provides a theoretical foundation for future advances towards behavioural adequacy. The article also argues against the minimalist analysis of the was/were alternation in Buckie (Adger, 2006).
Investigation of micro lens multi spot generator for parallel micromachining of silicon with picosecond and nanosecond laser

Multi spot optics are used for parallelizing production and therefore enabling large-scale material processing. These elements split the beam into a periodic spot pattern with a defined grid and spot size. The challenge lies in the generation of a homogeneous envelope. Micro lens arrays offer a high flexibility in dimensions and shapes for the generation of different multi spot patterns. Within the paper we present the investigation of a micro lens array in a fly's eye condenser setup for the generation of homogeneous spot patterns. The principal functionality of the multi spot generator is shown and constraints of this setup are demonstrated. The multi spot generator is used for micro structuring of silicon with a nanosecond and a picosecond laser both at a wavelength of 355 nm. The multi spot generator splits the incoming beam into a linear spot matrix with 28 single spots. The ablation rate and structure quality using a multi spot generator are investigated compared to conventional treatment. It can be shown, that both ablation efficiency and structure quality can be increased by using a multi spot generator.
“Hidden hydrogen” in as-grown ZnO

An O–H stretching line at 3326.3cm−1 was previously assigned to a shallow donor that is introduced into ZnO by H. This infrared line has been found to appear in as-grown ZnO samples when they are annealed near 400 °C without an external source of H, showing that there is an H-containing defect in commercially available ZnO that is not seen by infrared spectroscopy that can be converted into a shallow donor. The interstitial H2 molecule in ZnO is suggested as a candidate for the “hidden” H species.
Hopfian and Co-Hopfian objects

The aim of the present paper is to study Hopfian and Co-Hopfian objects in categories like the category of rings, the module categories A-mod and mod-A for any ring A. Using Stone's representation theorem any Boolean ring can be regarded as the ring A of clopen subsets of compact Hausdorff totally disconnected space X. It turns out that the Boolean ring A will be Hopfian (resp. co-Hopfian) if and only if the space X is co-Hopfian (resp. Hopfian) in the category Top. For any compact Hausdorff space X let CR(X) (resp. CC(X)) denote the R (resp. C)-algebra of real (resp. complex) valued continuous functions on X. Using Gelfand's representation theorem we will prove that CR(X) (CC(X)) is Hopfian (respectively co-Hopfian) as an R(C) algebra if and only if X is co-Hopfian (respectively Hopfian) as an object of Top. We also study Hopfian and co-Hopfian compact topological manifolds.