Miracle-dz/UniFAR-FTUs huggingface dataset:
Computational pitfalls in tractable grammatical formalisms

geboren te Amsterdam. Computational pitfalls in tractable grammatical formalisms / Marten Henrik Trautwein. -Amsterdam :Institute for Logic, Language and Computation. -Ill. -(ILLC dissertation series ; 1995-15) Proefschrift Universiteit van Amsterdam. -Met index, lit. opg. ISBN 90{74795{34{x NUGI 855 Trefw. : complexiteitstheorie / computerlingu stiek. Acknowledgments This thesis is the end-product of the NWO-project \Complexity Theory and Grammatical Theories," which was applied for by Theo Janssen and Leen Torenvliet. I would neither have started nor completed this thesis without the support in its widest sense of many people. First I want to thank my secular parents | Connie and Freek | and my scientiic parents | Leen, Theo, and Peter | for the free education they gave me. I am grateful for the opportunities they provided and for accepting my choices. I hope that they are not disappointed that I did not follow in their footsteps. I am indebted to the graduation committee | in particular Johan van Benthem, Machtelt Bolkestein, Michael Moortgat, and Bill Rounds | for their valuable criticism in reviewing this thesis. I also thank my \paranimfen" | Arie Mijnliee and Paul Vriend | and my brother | Kees// | for spending their valuable time on proofreading my work and their eagerness to help with anything. I appreciated their help and support during our mutual studies, and I missed their contributions in the past four years. With joy I recall my visits at the Research Institute for Language and Speech in Utrecht and the Department of Computational Linguistics of the University of Amsterdam. I am grateful to everybody who made these stays a pleasant experience. Special thoughts go to Kees and Koen who proved extremely valuable in solving song fragments, and Tjoe Liong and Dik who illuminated the theory of Functional Grammar. I wish to thank my colleagues at the third oor for the appreciation I received as cooee manager. Especially, and all the others who joined me for lunch. Most of all I am indebted to my closest friends | Marianne, Frank, Frans, Petra, Vincent, and Irma | who sometimes worried over my progress. I am also grateful to the friends who waited patiently for me when I was busy, but were ready for me when a songquiz had to be solved Before I nish oo let me go back to the early eighties, when Els and Wytse organized my brother's and mine initial meeting with a computer. In my view they …
Reconstructing tephra fall deposits via ensemble-based data assimilation techniques

Abstract. In recent years, there has been a growing interest in ensemble approaches for modelling the atmospheric transport of volcanic aerosol, ash, and lapilli (tephra). The development of such techniques enables the exploration of novel methods for incorporating real observations into tephra dispersal models. However, traditional data assimilation algorithms, including ensemble Kalman filter (EnKF) methods, can yield suboptimal state estimates for positive-definite variables such as those related to volcanic aerosols and tephra deposits. This study proposes two new ensemble-based data assimilation techniques for semi-positive-definite variables with highly skewed uncertainty distributions, including aerosol concentrations and tephra deposit mass loading: the Gaussian with non-negative constraints (GNC) and gamma inverse-gamma (GIG) methods. The proposed methods are applied to reconstruct the tephra fallout deposit resulting from the 2015 Calbuco eruption using an ensemble of 256 runs performed with the FALL3D dispersal model. An assessment of the methodologies is conducted considering two independent datasets of deposit thickness measurements: an assimilation dataset and a validation dataset. Different evaluation metrics (e.g. RMSE, MBE, and SMAPE) are computed for the validation dataset, and the results are compared to two references: the ensemble prior mean and the EnKF analysis. Results show that the assimilation leads to a significant improvement over the first-guess results obtained from the simple ensemble forecast. The evidence from this study suggests that the GNC method was the most skilful approach and represents a promising alternative for assimilation of volcanic fallout data. The spatial distributions of the tephra fallout deposit thickness and volume according to the GNC analysis are in good agreement with estimations based on field measurements and isopach maps reported in previous studies. On the other hand, although it is an interesting approach, the GIG method failed to improve the EnKF analysis.
Acoustics and vibration animations: A surprisingly successful website

For the past 8 years the author has been creating mathematically and physically correct computer animations for use in teaching acoustics to advanced undergraduate engineering and science majors [D. Russell, J. Acoust. Soc. Am. 106, 2197 (1999)]. Compiling these animations, along with supporting text, on a web site (http://www.kettering.edu/∼drussell/demos.html) has resulted in a surprising response from students, teachers, and professionals who have found the animations useful for their own presentations, study, or courses. Unsolicited recognition in the form of web awards and coverage in magazines adds weight to the usefulness of well‐made animations for conveying difficult concepts to a wide audience. This presentation will showcase as many of the animations as possible, especially newer ones, including: oscillation, wave superposition, reflection and refraction, particle motion for various wave types, radiation from simple and complex sources, room modes, waves on strings and membranes, bending waves .
--------------------------------------------------------------------------------------------------------------------------------------------------THE PROTECTIVE ROLE OF BENINCASA HISPIDA ON DICLOFENAC SODIUM INDUCED HEPATOTOXICITY IN ALBINO RAT MODEL

The objective of the present investigation was to study the protective role of aqueous extract of pulps of Benincasa hispida (BH) on diclofenac sodium- induced hepatotoxicity model in adult male albino rats. Hepatotoxicity in rats was caused by diclofenac sodium at a dose of 10 mg- /ml/kg body weight. Hepamerz (L-ornithine, L- aspartate) was administered orally as standard hepatoprotective agent for 14 consecutive days prior to diclofenac sodium treatment at a dose of 10mg- /ml/kg body weight. This drug has many side effects. These side effects have prompted the scientific world for the search of alternative herbal remedies of liver damage. In our country BH is easily available, cheap and has no side effects. The aqueous pulp extract of BH was administered orally to rats daily for 14 days before diclofenac sodium treatment. The biochemical parameters were investigated. The results indicated that biochemical changes produced by diclofenac sodium were restored to normal by aqueous extract of pulps of BH. The aqueous pulp extract of BH showed significant hepatoprotective effect through the modulation of antioxidant - mediated mechanism by altering serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), superoxide dismutase (SOD) and catalase (CAT) activities and reduced glutathione (GSH) and lipid peroxidation (LPO) levels - against diclofenac sodium - induced hepatotoxicity model in rats.
Stability of two-phase vertical flow in homogeneous porous media

Immiscible two-phase flow in porous media, which results from the downward injection of a heavier fluid or upward injection of a lighter fluid, is characterized by two shocks, one at each end of a rarefaction wave. The specific details of the saturation profile, such as the shock speeds and the shock saturations, are determined by the fractional flow function for given values of the mobility ratio and the gravity number. We employ a normal mode, matched asymptotic expansion analysis to obtain analytical expressions governing the stability behavior of such flows. Instability occurs at both ends of the one-dimensional base saturation profile with unique characteristics such that the maximum growth rate decreases both when the mobility ratio is increased at the front end and decreased at the back end. This unusual behavior is explained in terms of vorticity eigenfunctions related to nonmonotonic mobility profiles. Analysis of stability behavior as a function of fractional flow profile shows that although the.
ERROR ESTIMATES FOR STOKES PROBLEM WITH TRESCA FRICTION CONDITIONS

In this paper, we present and study a mixed variational method in order to approximate, with the finite element method, a Stokes problem with Tresca friction boundary conditions. These non-linear boundary conditions arise in the modeling of mold filling process by polymer melt, which can slip on a solid wall. The mixed formulation is based on a dualization of the non-differentiable term which define the slip conditions. Existence and uniqueness of both continuous and discrete solutions of these problems is guaranteed by means of continuous and discrete inf-sup conditions that are proved. Velocity and pressure are approximated by P1 bubble-P1 finite element and piecewise linear elements are used to discretize the Lagrange multiplier associated to the shear stress on the friction boundary. Optimal a priori error estimates are derived using classical tools of finite element analysis and two uncoupled discrete inf-sup conditions for the pressure and the Lagrange multiplier associated to the fluid shear stress.
The frequency of hydrogen white dwarfs as observed at high signal to noise ratio

Despite their relatively high stability and slow evolution, white dwarfs are subject to important changes as they cool, since little material is required to contaminate an atmosphere that is only a few meters thick. With an eye to these complexities, about 140 white dwarfs were observed on eight nights in 1982, with about 10,000 to 30,000 photons/pixel being detected near the central wavelengths of the double CCD camera used. Steep Balmer decrements are noted to occur in the cooler degeneration due to increasing He/H ratio. The predominance of non-DA stars as late evolutionary stages prompts questions as to the fate of the accreted and residual H in postasymptotic giant branch evolution. No definitive theoretical argument is found to explain how most of the residual hydrogen is destroyed. 51 references.
Assessment of surface profile data acquired by a stylus profilometer

This paper analyzes the 2D and 3D distortion effects of a measured profile caused by the stylus tip radius of a stylus-type surface profilometer. On the basis of our analysis results, we propose the selection criteria for the stylus tip radius to improve the reliability of measurement results. For that purpose, a simulation algorithm has been devised and implemented for 2D and 3D measurement simulations, and the 3D surface texture used in simulation was obtained using an atomic force microscope from an actual machined surface to improve the reliability of simulation results. The simulation results were compared with the measured results from the same specimen using a roughness tester, and the validity of analysis via the simulation proposed in this study was confirmed. Cumulative power spectral analysis was performed for the 2D and 3D simulated profiles obtained from simulation. On the basis of the analysis results, an effective frequency component field was clarified using a stylus-type profilometer, and the selection criteria of the stylus tip radius for measurement were proposed considering the surface texture characteristics of the specimen.
Extinction and non-extinction for a polytropic filtration equation with a nonlocal source

In this article, the authors establish the conditions for the extinction of solutions, in finite time, of the fast diffusive polytropic filtration equation u t = div(|∇u m | p−2∇u m ) + a∫Ω u q (y, t)dy with a, q, m > 0, p > 1, m(p − 1) < 1, in a bounded domain Ω ⊂ R N (N > 2). More precisely speaking, it is shown that if q > m(p − 1), any non-negative solution with small initial data vanishes in finite time, and if 0 < q < m(p − 1), there exists a solution which is positive in Ω for all t > 0. For the critical case q = m(p − 1), whether the solutions vanish in finite time or not depends on the comparison between a and μ, where μ = ∫ Ωφ p−1(x)dx and φ is the unique positive solution of the elliptic problem −div(|∇φ| p−2∇φ) = 1, x ∈ Ω; φ(x) = 0, x ∈ ∂Ω.
HF radio wave acceleration of ionospheric electrons: Analysis of HF‐induced optical enhancements

The shape of the HF-pump modified electron energy distribution has long been a central question in the field of ionospheric high-frequency radio wave modification experiments. Here we present estimates of the enhanced differential electron flux, from 1.9 to 100 eV based on optical multiwavelength (6300, 5577, 8446, and 4278 A) data and 930 MHz incoherent scatter radar measurements of ion temperature, electron temperature and concentration. According to our estimate, the electron energy distribution is depleted in the energy range of 2 to approximately 4 eV, probably caused by electron excitation of vibrational states in N2. At the higher energies the electron energy distribution has a nonthermal tail. Further we show that the altitude variations of the four optical emissions should differ both in altitude coverage and center altitude.
Effect of nitrogen on the electrical and structural properties of triode‐sputtered tantalum films

The structural and electrical properties of nitrogen‐doped tantalum films, sputtered in a dc triode system, have been investigated. For constant sputtering voltage and current, the tantalum deposition rate decreased with increasing nitrogen flow rate; at a flow rate of 12 cm3 min−1, the deposition rate was 75% of the rate obtained without the addition of nitrogen. The density of the films decreased from 15.4 to 9.8 g cm−3 as the nitrogen flow increased from 0 to 12 cm3 min−1. The net effect on the film thickness is an increase from 2700 to 3800 A for films on glass substrates. Films were also deposited on ceramic substrates at the same time. Both x‐ray diffractometer and powder camera analysis showed that the films consisted of the bcc Ta phase at nitrogen flows up to 3 cm3 min−1 but the lattice was approximately 3% larger than for bulk Ta. The hcp Ta2N phase appeared at flow rates above 3 cm3 min−1 and the change from bcc Ta to hcp Ta2N was accompanied by an increase in the room‐temperature coefficient o.
Inherent Bounds on Forecast Accuracy due to Observation Uncertainty Caused by Temporal Sampling

AbstractSynoptic observations are often treated as error-free representations of the true state of the real world. For example, when observations are used to verify numerical weather prediction (NWP) forecasts, forecast–observation differences (the total error) are often entirely attributed to forecast inaccuracy. Such simplification is no longer justifiable for short-lead forecasts made with increasingly accurate higher-resolution models. For example, at least 25% of t + 6 h individual Met Office site-specific (postprocessed) temperature forecasts now typically have total errors of less than 0.2 K, which are comparable to typical instrument measurement errors of around 0.1 K. In addition to instrument errors, uncertainty is introduced by measurements not being taken concurrently with the forecasts. For example, synoptic temperature observations in the United Kingdom are typically taken 10 min before the hour, whereas forecasts are generally extracted as instantaneous values on the hour. This study develo.
The pulsed hard X-ray spectrum of PSR B1509-58

Oriented Scintillation Spectrometer Experiment (OSSE) observed the 150 ms X-ray pulsar PSR B1509-58 m the supernova remnant MSH 15-52 for 4 weeks in 1992. The pulsed spectrum from 50 keV to 5 MeV is well represented by a single-power-law photon spectrum of the form (3.14 +/- 0.16) x 10(exp -6) x (E/118.5 keV)(exp -1.68 +/- -0.09) photons cm(exp -2)s(exp -1)keV(exp -1). This is significantly harder than the Crab pulsar spectrum in this energy range. The Ginga soft X-ray spectrum (2-60 keV) reported by Kawai et al. is significantly harder than the observed OSSE spectrum and predicts a flux 2 times higher than we observe in the approximately 55-170 keV energy band. This requires a break to a steeper spectrum somewhere in the intermediate energy range (approximately 20-80 keV). The spectrum must soften again at higher energies or the pulsar would have easily been detected by EGRET, COS B, and SAS 2.
The number of irreducible factors of a polynomial. I

Let F(x) be a polynomial with coefficients in an algebraic number field k. We estimate the number of irreducible cyclotomic factors of F in k[x], the number of irreducible noncyclotomic factors of F, the number of nth roots of unity among the roots of F, and the number of primitive nth roots of unity among the roots of F. All of these quantities are counted with multiplicity and estimated by expressions which depend explicitly on k, on the degree of F and height of F, and (when appropriate) on n. We show by constructing examples that some of our results are essentially sharp
Dust reverberation : a model for the infrared variations of Fairall 9

Over a period of 10 yr starting in 1978, the ultraviolet flux from the quasar Fairall 9 was observed by Clavel, Wamsteker, & Glass to have varied by over a factor of 30. The infrared varied as well, with light curves very similar in shape but evincing a delay of about 1 yr relative to the UV. Clavel et al. suggested that the data were consistent with infrared reradiation of the UV light by dust. In this paper a detailed model is described in which dust heated by the central optical/UV source is responsible for the infrared emission from Fairall 9
Contrasting Vertical Structure of Recent Arctic Warming in Different Data Sets

Arctic region is experiencing strong warming and related changes in the state of sea ice, permafrost, tundra, marine environment and terrestrial ecosystems. These changes are found in any climatological data set comprising the Arctic region. This study compares the temperature trends in several surface, satellite and reanalysis data sets. We demonstrate large differences in the 1979-2002 temperature trends. Data sets disagree on the magnitude of the trends as well as on their seasonal, zonal and vertical pattern. It was found that the surface temperature trends are stronger than the trends in the tropospheric temperature for each latitude band north of 50? N for each month except for the months during the ice-melting season. These results emphasize that the conclusions of climate studies drawn on the basis of a single data set analysis should be treated with caution as they may be affected by the artificial biases in data.
Linear theory of abstract functional differential equations of retarded type

Abstract The purpose of this paper is to provide an extension of the linear theory of functional differential equations of retarded type to abstract equations. Such equations include examples borrowed from population dynamics to which the theory applies. An application will be given elsewhere. Our main effort in this work consists in providing a suitable extension of the formal adjoint equation and the formal duality. The solutions of the linear autonomous retarded functional differential equation x′(t) = L(x t ), (1) where L is a bounded linear operator mapping the space C([−r, 0]; E) into the Banach space E, define a strongly continuous translation semigroup. We show the existence of a direct sum decomposition of C([−r, 0]; E) into two subspaces which are semigroup invariants. The flow induced by the solutions of Eq. (1) can be interpreted as the flow induced by an ordinary differential equation in a finite-dimensional space. We explicitly characterize this decomposition by an orthogonality relation associated to a certain definition of formal duality. The existence of an integral representation for the operator L leads to an equation formally adjoint to (1) characterizing the projection operator defined by the above decomposition of C([−r, 0]; E).
Estimates of human immunodeficiency virus prevalence and proportion diagnosed based on Bayesian multiparameter synthesis of surveillance data

Summary. Estimates of the number of prevalent human immunodeficiency virus infections are used in England and Wales to monitor development of the human immunodeficiency virus–acquired immune deficiency syndrome epidemic and for planning purposes. The population is split into risk groups, and estimates of risk group size and of risk group prevalence and diagnosis rates are combined to derive estimates of the number of undiagnosed infections and of the overall number of infected individuals. In traditional approaches, each risk group size, prevalence or diagnosis rate parameter must be informed by just one summary statistic. Yet a rich array of surveillance and other data is available, providing information on parameters and on functions of parameters, and raising the possibility of inconsistency between sources of evidence in some parts of the parameter space. We develop a Bayesian framework for synthesis of surveillance and other information, implemented through Markov chain Monte Carlo methods. The sources of data are found to be inconsistent under their accepted interpretation, but the inconsistencies can be resolved by introducing additional ‘bias adjustment’ parameters. The best‐fitting model incorporates a hierarchical structure to spread information more evenly over the parameter space. We suggest that multiparameter evidence synthesis opens new avenues in epidemiology based on the coherent summary of available data, assessment of consistency and bias modelling.
Electron-cyclotron wave propagation, absorption and current drive in the presence of neoclassical tearing modes

We analyze the propagation of electron-cyclotron waves, their absorption and current drive when neoclassical tearing modes (NTMs), in the form of magnetic islands, are present in a tokamak plasma. So far, the analysis of the wave propagation and power deposition in the presence of NTMs has been performed mainly in the frame of an axisymmetric magnetic field, ignoring any effects from the island topology. Our analysis starts from an axisymmetric magnetic equilibrium, which is perturbed such as to exhibit magnetic islands. In this geometry, we compute the wave evolution with a ray-tracing code, focusing on the effect of the island topology on the efficiency of the absorption and current drive. To increase the precision in the calculation of the power deposition, the standard analytical flux-surface labeling for the island region has been adjusted from the usual cylindrical to toroidal geometry. The propagation up to the O-point is found to be little affected by the island topology, whereas the power absorbed and the driven current are significantly enhanced, because the resonant particles are bound to the small volumes in between the flux surfaces of the island. The consequences of these effects on the NTM evolution are investigated in terms of the modified Rutherford equation.