Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling attendance at Spanish professional football league

Prediction of demand for professional sports is increasingly drawing the attention of economists. We apply linear mixed models for modeling attendance figures at Spanish professional football. We investigate economic variables, such as the price of the tickets or the size of the market, and sporting variables, such as the quality of a team or the level of competition within the league, as potential predictors of attendance. It turns out that a model with temporally correlated random team effects provides good forecasts of attendance at a time horizon of two seasons. Results from this model agree with economic theory.
A Multilevel, Multivariate Model for Studying School Climate With Estimation Via the EM Algorithm and Application to U.S. High-School Data

In many studies of school climate, researchers ask teachers a series of questions, and the responses to related questions are averaged or summed to create a scale score for each teacher on each dimension of climate under investigation. Researchers have disagreed, however, about the analysis of such data: Some have utilized the teacher as the analytic unit, and some have utilized the school as the unit. In this article, we propose a three-level, multivariate statistical modeling strategy that resolves the unit-of-analysis dilemma and unifies thinking about the analysis in such studies. A reanalysis of U. S. high-school data illustrates how to estimate and interpret: (a) the level of interteacher agreement on each climate dimension; (b) the internal consistency of measurement at the teacher and school levels; and (c) the correlations among “true” climate scores at each level. A linear model analysis utilized teacher control over school and classroom policy and teacher morale as bivariate latent outcomes to be predicted by school-level variables (e.g., sector, size, composition) and by teacher-level variables (e.g., education, race, sex, subject matter). Implications for conceptualization, design, analysis, and interpretation in future studies of school climate are considered.
The Correlation of Postoperative Femoral Component Rotation Angle and Patella Tilt Angle with Clinical Results in Total Knee Arthroplasty

Purpose: The aim of this study was to analyze the correlation of postoperative femoral component rotation angle and patella tilt angle with clinical results for total knee arthroplasty. Materials and Methods: Ninety-six cases in 48 patients who underwent total knee arthroplasty between March 2002 and February 2010 were enrolled. Femoral component rotation angle (FRA) and patella tilt angle (PTA) were measured with postoperative computed tomography. Clinical results were evaluated using American Knee Society knee score & function score and Feller's patella score. We analyzed the correlation of FRA and PTA with clinical outcomes. We also compared clinical results between the PFC Ⓡ Sigma group and the Scorpio Ⓡ group, and the patello-femoral symptom group and a symptom-free group. Results: The mean FRA was 1.40 o of internal rotation. The patellar tilt angle was 3.79 o of lateral tilt. The mean knee score was 90.5, the function score was 77.4, and the patella score was 23.9. There was a significant difference between FRA and knee scores (p=0.031, r=−0.284). There were no significant differences between FRA and function score or patella score. The correlation of PTA and clinical results was not significant. The mean FRA was 2.00 o of internal rotation in the PFC Ⓡ Sigma group, and it was significantly different than for the Scorpio NRG Ⓡ group which had 0.81 o of internal rotation; but there were no significant differences between the two groups in clinical results. The patello-femoral symptom group deviated more from the mean FRA than did the symptom-free group. Conclusion: Internal rotation of the femoral component is correlated with poor clinical results after total knee arthroplasty. The correlation of patella tilt angle and clinical results was not significant.
Fast variability of BL Lacertae at 1 μm

We present the results of photometric observations of BL Lacertae at 1 mm performed during the strong outburst that occurred in the summer of 1997. Measurements were carried out using the F99 filter of the Arizona system. Simultaneous observations in the B and V bands were made with other telescopes. Large and fast variations were observed on the night of August 2 whenthebrightnessofBLLacertaechangedby,0.5maginabout2h:thevariationamplitude is greater at higher frequency. Some implications of these results for the origin of the fast variations are discussed. We also report the first F99 calibration for three reference stars in the BL Lac field.
Luminosities and mass-loss rates of carbon stars in the Magellanic Clouds

Dust radiative transfer models are presented for 60 carbon stars in the Magellanic Clouds (MCs) for which 5‐35 µm Spitzer infrared spectrograph (IRS) spectra and quasi-simultaneous ground-based JHKL photometry are available. From the modelling, the luminosity and massloss rate are derived (under the assumption of a fixed expansion velocity and dust-to-gas ratio), and the ratio of silicon carbide (SiC) to amorphous carbon (AMC) dust is also derived. This ratio is smaller than observed in Galactic carbon stars, as has been noted before. Light curves for 36 objects can be retrieved from the massive compact halo object (MACHO) and optical gravitational lensing experiment (OGLE) data bases, and periods can be derived for all but two of these. Including data from the literature, periods are available for 53 stars. There is significant scatter in a diagram where the mass-loss rates are plotted against luminosity, and this is partly due to the fact that the luminosities are derived from single-epoch data. The mass-loss rates for the MC objects roughly scatter around the mean relation for Galactic C-stars. The situation is better defined when the mass-loss rate is plotted against pulsation period. For a given period, most of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) stars have mass-loss rates that are in agreement with that observed in Galactic carbon stars (under the assumption that these objects have an expansion velocity and dust-to-gas ratio typical of the mean observed in Galactic carbon Miras). For some SMC sources only, the IRS spectrum at longer wavelengths falls clearly below the model flux predicted by a constant mass-loss rate. An alternative model with a substantial increase of the mass-loss rate to its present-day value over a time-scale of a few tens of years is able to explain the spectral energy distribution (SED) and IRS spectra of these sources. However, the probability to have two such cases in a sample of 60 is small, and makes this not a likely explanation (and testable by re-observing these objects near the end of the lifetime of Spitzer). Alternative explanations are (ad hoc) changes to the dust emissivity at longer wavelengths, and/or deviations from spherical symmetry.
The size distribution of dust grains in single clouds — I. The analysis of extinction using multicomponent mixtures of bare spherical grains

We demonstrate that the method of regularization designed to resolve inverse problems may be successfully applied in analysis of interstellar extinction_ The absolute extinction curves of apparently single clouds, seen towards the stars HD 147165,179406 and 202904, have been derived and modelled using multicomponent bare spherical dust grain mixtures containing graphite, silicates, various types of amorphous carbon, SiC and water ice. We find that the grain size distributions are essentially different from Mathis, Rumpl & Nordsieck's (MRN) power law and may be multimodal. From the recent data about reduced ('" 2/3 solar) cosmic abundances, it has been shown that a mixture of graphite, silicate and ice grains explains quite satisfactorily the extinction towards the stars under analysis whereas a traditional mixture of graphite and silicate grains fails.
HIGH ABUNDANCES OF CIRCUMSTELLAR AND INTERSTELLAR C-ANOMALOUS PHASES IN THE PRIMITIVE CR3 CHONDRITES QUE 99177 AND MET 00426

QUE 99177 and MET 00426 are the first known CR3 chondrites and have largely escaped the aqueous alteration experienced by most of the CR chondrite group. In addition to high presolar silicate and oxide grain abundances, these meteorites also contain high abundances of phases with anomalous C isotopic compositions. Presolar SiC abundances (∼65 ppm) are consistent with independent estimates for CR1 and CR2 chondrites, indicating that aqueous alteration does not destroy SiC, but are significantly higher than earlier abundance estimates based on noble gas contents. Particularly notable are the high abundances (∼120 ppm) of carbonaceous matter with anomalous C isotopic compositions that probably formed in cold molecular clouds via ion–molecule reactions. The observation of both 13C-enriched and 13C-depleted compositions suggests that multiple chemical pathways contribute to the formation of this material. The abundance of such material is significantly higher in QUE 99177 and MET 00426 than in other primitive meteorites and attests to the primitive nature of the CR3 chondrites.
Horizontal cooperative purchasing

Purchasing in groups is a concept that is becoming increasingly popular in both the private and public sector. Often, the advantages such as lower purchase pricese, learning from each other, and reduced transaction costs outweigh set-up and management costs and drawbacks such as disclosure of sensitive information and the fear of free-riding group members. The concept is not always successful though. Still, it has received relatively little attention in management research. In this thesis, we study the establishment and management of purchasing groups. We define purchasing groups as organizations in which horizontal cooperative purchasing takes place. We define horizontal cooperative purchasing as the operational, tactical, and/or strategic cooperation between two or more organizations in one or more steps of the purchasing process by pooling and/or sharing their purchasing volumes, information, and/or resources.
On the Value of Dedekind Sums and Eta-Invariants for 3-Dimensional Lens Spaces

is impossible to evaluate the sum for $n\geqq 2$ as a polynomial on $p$ and $q$ . However, in case of $n=2$ , we can express the sum as a finite sum with fewer terms using the sequence of remainders in the Euclidean algorithm for calculating the $gcd(p, q)$ (see T. M. Apostol [1], p. 73). On the other hand, instead of evaluating the sum, the reciprocity formulas which can be used as an aid in calculating the Dedekind sums have been studied. The only results we have known are:
Sources of Mesoscale Variability of Gravity Waves. Part II: Frontal, Convective, and Jet Stream Excitation

Abstract We present studies of four cases of mesoscale variance enhancements of horizontal velocity and temperature due to frontal activity, nonfrontal convection, and wind shear. These data were obtained aboard commercial aircraft during the Global Atmospheric Sampling Program (GASP) in 1978 and 1979 and from the corresponding meteorological analyses and satellite imagery. Additional GASP data were used to permit a statistical assessment of the importance of various sources of enhanced variances. Our results, and those in a companion paper addressing the variance enhancements associated with topography, represent refinements of previous source analyses using the GASP dataset. Significant findings include mean variance enhancements of velocity and temperature due to convection and jet-stream flow ranging from ∼2 to 8 for 64-km and 256-km data segments, and enhancements for individual segments as high as ∼20 to 100. The mean 64-km variance enhancement for all variables and source types, relative to a quies.
Outlier Resistant Alternatives to the Ratio Estimator

Abstract Many techniques have been suggested to lower the impact of outliers on sample survey estimates. Outliers can be downweighted by winsorization; that is, by replacing extreme data points by a data-dependent or a predetermined value before calculating estimates. Another approach is to reduce the weight of outliers, from the inverse sampling fraction to 1, in the estimation of population characteristics. In this article the problem of estimating the population mean using auxiliary information in the presence of outliers is considered. A resistant version of the ratio estimator is introduced. It is constructed with a M or a GM estimator of the slope of the regression model through the origin, which is implicitly called on when considering the ratio estimator. The asymptotic biases and asymptotic variances of the proposed alternatives to the ratio estimator are calculated with respect to the randomization of the sampling plan. The selection of a resistant estimator is seen to involve a trade-off betwee.
Sea Ice Rheology

The polar oceans of Earth are covered by sea ice. On timescales much greater than a day, the motion and deformation of the sea ice cover (i.e., its dynamics) are primarily determined by atmospheric and oceanic tractions on its upper and lower surfaces and by internal ice forces that arise within the ice cover owing to its deformation. This review discusses the relationship between the internal ice forces and the deformation of the ice cover, focusing on representations suitable for inclusion within global climate models. I first draw attention to theories that treat the sea ice cover as an isotropic continuum and then to the recent development of anisotropic models that deal with the presence of oriented weaknesses in the ice cover, known as leads.
Causal inference in block-randomized experiments: Analysis based on Neyman's stochastic causal model

In Neyman’s causal model (NCM), each unit included in a two-arm randomized experiment has a pair of potential outcomes – one outcome would be observed under treatment, the other under control. In the stochastic version of NCM, both potential outcomes are viewed as (possibly) non-degenerate random variables to allow for stochastic effects of post-interventional factors, such as random measurement error. The unit-level treatment effect is the expected outcome under treatment minus that under control. The sample average treatment effect (SATE) is the mean of the unit-level effects in the set of all units included in the experiment. The population average treatment effect (PATE) is the mean of the unit-level effects defined on the population of all units eligible for experiment. The purpose of this paper is to develop a non-parametric theory of inference about SATE and PATE in block-randomized experiments, using the mathematical formalism of stochastic NCM. Inference about SATE is examined under randomization distribution without a probability model for selection of units into experiment. For inference about PATE two probability models for selection are considered: (1) simple random sampling and (2) stratified random sampling, each followed by block-randomized treatment assignment. It is shown that under these conditions, the ordinary “difference of means” estimator (mean observed outcome under treatment minus that under control) is consistent for both SATE and PATE. The variance of this estimator is derived under randomization distribution alone and under simple random sampling and stratified random sampling as selection models. Variance estimators producing confidence intervals with nominal asymptotic coverage for PATE under these selection models are proposed, and it is also shown that these intervals have at least nominal asymptotic coverage for SATE under randomization distribution. Thus, when a selection model is correctly specified, the proposed methods guarantee valid inference about both SATE and PATE, while under incorrect specification of the selection model valid inference about SATE is still guaranteed. This is an important property because in many types of randomized experiments (e.g., clinical trials in medicine), units are not selected into experiment by a mechanism with known selection probabilities.
Feasibility study of superharmonic imaging using chirps

Superharmonic imaging (SHI) targets a combination of the 3rd to 5th harmonics. It was proven to have certain advantages in comparison with the established imaging standards in medical utrasound. SHI enhances the spatial resolution and improves the quality of echographic images, mainly by eliminating reverberation artifacts at the chest wall. However, SHI suffers from ripple artifacts, originating from the spectral gaps in between harmonics, and degrading the temporal resolution. To solve this a chirp-based SHI protocol was employed and its characteristics investigated, i.e. point spread function (PSF). The protocol was implemented for an interleaved phased array probe (44+44 elements tuned at 1.0+3.7MHz), connected to a fully programmable ultrasound system. A linear chirp (center frequency 1MHz; bandwidth 40%) was used for excitation. To obtain the PSF, the RF traces were recorded at focus along the lateral axis and convolved with the decoding signal. This was computed using KZK simulations. A PSF comparison between a superharmonic chirp and the 3rd-harmonic of a 2.5-cycle Gaussian apodized sinus burst at 1MHz showed a decrease in axial pulse length of 46% at -6dB and 32% at the -20dB level in favor of SHI. Chirp based SHI is virtually free of ripple artifacts and therefore feasible.
When is a p-adic power series an endomorphism of a formal group?

If f(x) is a noninvertible endomorphism of a formal group, then we have that f(x) commutes with an invertible series and O[[x]] is Galois over O[[fn(x)]] for all n ∈N. We shall prove that the converse of this statement is also true.
A drift ordered short mean free path description for magnetized plasma allowing strong spatial anisotropy

Short mean free path descriptions of magnetized plasmas have existed for almost 50 years so it is surprising to find that further modifications are necessary. The earliest work adopted an ordering in which the flow velocity is assumed to be comparable to the ion thermal speed. Later, less well-known studies extended the short mean free path treatment to the normally more interesting drift ordering in which the pressure times the mean flow velocity is comparable to the diamagnetic heat flow. Such an ordering is required to properly retain the temperature gradient terms in the viscosity that arise from the gyrophase dependent and independent portions of the distribution function. The treatment herein corrects the expressions for the parallel and perpendicular collisional ion viscosities found in these later treatments which use an approximate truncated polynomial expression for the distribution function and neglect the nonlinear piece of the collision operator due to its bilinear form. The modified parallel.
Eccentric orbit generalization and simultaneous solution of binary star light and velocity curves

The computation of binary star light and radial velocity curves are discussed, including the effects of eccentric orbits and nonsynchronous rotation. Logical relations needed to impose physical constraints (semidetached condition, etc.) are specified. Some of the more important mathematical relations are also given. One can now model semidetached, detached, double-contact, and X-ray binaries for arbitrary rotation rates and orbital eccentricity. Contact binaries can also be modeled, but are restricted to the synchronous, circular orbit case. In all cases the figures of the components and the surface gravity fields are described by surfaces of constant potential energy.
THE DEFINITE INTEGRAL AND COMPUTER

In this paper the results of the learning concept of definite integral and numeric integration with the computer is presented. The tested students attend ˇ Chemical Technological college. The aim of this test was to check the student's theoretical, visual and practical knowledge of definite integral. In almost all secondary schools definite integral and its applications are studied. The concept of definite integral is almost always introduced as the Riemann integral, which is in turn defined in terms of Riemann sums, and its geometric interpretation. For secondary school pupils, as well as for high school and university students, this definition is hard to understand. The courses of Numerical mathematics at all levels contain topics on numerical integration, which is partly based on Riemann sums. With the aid of mathematical software for visualization and computation of approximate integrals, the notion of definite integral and its calculation is more easily adopted by pupils and students. We present one possible approach to lecturing on approximate integration, based on our experience with the students ofChemical technological college and the students of Computer Science at the Faculty of Sciences, Novi Sad. We start by introducing the definite integral. The concept is explained by calculation of the area of a figure, and it is then formalized by using the Riemann sums and its geometrical interpretation. Left, middle and right rectangular rule are introduced from the start. Trapezoidal and Simpson's rule are introduced soon afterwards. Simpson's rule is first explained in its simple form, and later in the complex form. The computer was used to produce graphs and pictures, and substantial attention was devoted to developing interactive illustrations which are animated by changing parameters. In the class we used GeoGebra and Mathematica for visualization. While Mathematica satisfies most of our computing needs, it lacks interactively, which GeoGebra supplements in more than one way. Besides, GeoGebra is much simpler to use, and it is available in many languages, including pupils' native Serbian. Of no lesser importance is the fact that GeoGebra is free, while Mathematica is not.
Hybrid TS fuzzy modelling and simulation for chaotic Lorenz system

The projection of the chaotic attractor observed from the Lorenz system in the X–Z plane is like a butterfly, hence the classical Lorenz system is widely known as the butterfly attractor, and has served as a prototype model for studying chaotic behaviour since it was coined. In this work we take one step further to investigate some fundamental dynamic behaviours of a novel hybrid Takagi–Sugeno (TS) fuzzy Lorenz-type system, which is essentially derived from the delta-operator-based TS fuzzy modelling for complex nonlinear systems, and contains the original Lorenz system of continuous-time TS fuzzy form as a special case. By simply and appropriately tuning the additional parametric perturbations in the two-rule hybrid TS fuzzy Lorenz-type system, complex (two-wing) butterfly attractors observed from this system in the three dimensional (3D) X–Y–Z space are created, which have not yet been reported in the literature, and the forming mechanism of the compound structures have been numerically investigated.
Spectral methods for the simulation of incompressible flows in spherical shells

SUMMARY A spatial discretization of the incompressible Navier‐Stokes equation is presented in which the velocity is decomposed using poloidal and toroidal scalars whose spatial dependence is given in terms of spherical harmonics and Chebychev polynomials. The radial resolution needs to be large enough at any given angular resolution in order to avoid instability in the simulation of rotating flows. Several semi-implicit time steps are discussed. The most accurate scheme is an integrating factor technique. Copyright © 1999 John Wiley & Sons, Ltd.