Miracle-dz/UniFAR-FTUs huggingface dataset:
Multilevel and Longitudinal Modeling Using Stata

One of the most important responsibilities of statistics educators is the job of effectively communicating statistical concepts to students from outside of our discipline. Many textbooks have been written that tailor presentation to a specific audience. For example, students studying business, economics, psychology, and engineering frequently study introductory statistics using textbooks that use examples and case studies derived from their major field. However, until the publication of this text, students studying communication science did not have this same opportunity. (The author notes that his text is the first that focuses exclusively on statistical methodology in communication research.) Before considering what Statistical Methods for Communication Science is, it is useful to note what it is not. It is not flashy. Increasingly, introductory texts are designed to be visually appealing. They include glossy pictures, multicolor charts, and specially highlighted information. This text does not. It is printed entirely in black and white. A purist might point out that this really does not affect the substance of the book. Certainly that is the case, but the presentation will tend to affect the extent to which students use the book. For this reason, I think the book is best suited to more mature audiences. From the preface, it appears this was the author’s intent. He only discusses the book’s use for a graduate-level research methods course. One serious limitation of this book as a textbook, at any level, is the complete lack of homework problems. This is, perhaps, less of an issue in a graduate course. Nevertheless, any instructor adopting this textbook should expect to use other sources for crafting homework assignments. The text is written in a clear, straightforward manner. Figures are included where necessary and important formulas and equations are boxed to call attention to them. The selection of topics is excellent. In addition to basic introductory probability and statistics, the book includes substantial discussions of categorical data analysis, regression (simple and multiple), and analysis of variance. I found the sections on analysis of covariance and on interaction particularly useful. Frequently, these important topics are buried within chapters on regression or completely left out. Overall, as a reference text, I like this book a lot. It presents a wide range of important statistical topics in a no-nonsense, easy-to-follow format. Although it is not flashy, it contains a substantial amount of useful information. The book’s contextual slant toward communication science is likely to benefit students in that area. Unfortunately, it is also likely to keep students in other areas from considering the book. This is a shame, because the book is an excellent reference text and would serve any applied researcher very well.
Addressing challenges in lithography using sub-millisecond post exposure bake of chemically amplified resists

Chemically amplified photoresists require a post exposure bake (PEB), typically on a hot plate at 90-150°C for 30-120 seconds, to catalytically deprotect the polymer backbone. During PEB, excessive diffusion of the photo-generated acid results in loss of line edge definition, blurring of latent images and changes in the line edge roughness. Both acid diffusion and deprotection are thermally activated processes, with the relative rates affected by the time/temperature profile of the PEB. In this work, we introduce an alternate PEB method involving millisecond time frame heating over a temperature range of 300°C to 420°C using a continuous wave CO2 laser. A methodology is developed for characterizing the resist deprotection and acid diffusion kinetics under laser PEB (l-PEB) and comparing the behavior with conventional hot plate PEB. Results show that the deprotection rate sensitivity with temperature is smaller for l-PEB compared to that of hot plate PEB, suggesting a possible change in the deprotection mechanism. Acid diffusivity under l-PEB is reduced by a factor of 102-103 compared to values extrapolated from the hot plate PEB data. Under EUV exposure, patterns formed using l-PEB show significantly smoother surface roughness while requiring less than half the dose required for hot plate PEB - a direct consequence of enhanced deprotection at high PEB temperature and reduced acid diffusion in the millisecond time frame.
Generalized evolute in Klein spaces

We investigate in this paper the generalization of the enveloping theorem of an evolute of a curve on the euclidean plane to the case of figures in Klein spaces by the method of moving frame of E. Cartan [1]. The idea of this paper is the same with that of [3]. In addition we state the process of obtaining theorems in Klein spaces analogous to Euler-Savary’s theorem on the euclidean plane ([2] pp. 28-29).
ON ESTIMATING THE SIZE OF MOBILE POPULATIONS FROM RECAPTURE DATA

The estimation of the total size of plant or animal populations is of great importance in a variety of biological problems, which may relate to population growth, ecological adaptation, genetic constitution, natural selection and evolution, and so on. Obvious practical consequences are the maintenance of human food supplies and the control of insect pests. For human communities and populations of sessile organisms procedures employing fixed sampling units are available, but for mobile populations other methods must be used. The basic technique, which seems to have been first used by Lincoln (1930) to estimate the total number of duck in North America, and is sometimes referred to as the 'Lincoln Index', is as follows. One catches, marks and releases a certain number of animals taken at random from the population. A further random sample is caught and the proportion of marked animals noted. Then the total number of marked animals released divided by the proportion of marked animals in the sample captured can clearly be used as an estimate of the total population size. The same method was adopted independently by Jackson (1933), who used it for estimating the true density of tsetse flies. Jackson (1937, 1939) subsequently extended his treatment to allow for both birthand death-rates, advocating his 'negative' and ' positive' methods. Further work by Jackson (1940) took into account the effects of migration. Recapture methods have also been successfully applied to populations of Lepidoptera. Dowdeswell, Fisher & Ford (1940) caught, marked and released moths on several different days. On each day the marked insects were classified according to the day on which they had previously been released. Analysis of the data, which could be exhibited in a triangular array, or 'trellis' diagram, gave estimates of the size of the moth population for each day. The interpretation of trellis diagrams was further developed by Fisher & Ford (1947). They estimated daily numbers, taking into account a death-rate which was obtained from the average time interval between marking and recapture. A more detailed application of this procedure was made by D~owdeswell et al. (1949). Although in the various papers cited above effective use has been made of estimates of population size and of birthand death-rates, there has been little discussion for the most part of the precision of the results obtained. Jackson (1937, 1939) obtained both the population estimate and its variance for the 'negative' and 'Positive' methods by fitting a curve
Transient response of piezoelectric thin-film vibration sensor under pulse excitation

We present an analytical model to describe the transient response of a piezoelectric thin-film vibration sensor under pulse excitation. The structure of the thin-film vibration sensor consists of four suspended flexural piezoelectric lead zirconate titanate-on-silicon beam transducers and a central seismic mass. The model takes into account the effect of device geometry and materials properties of the piezoelectric thin film. The relationships between the dynamic behavior and voltage sensitivity with the device’s structure are established. It is found that with the increase of initial vibration magnitude U0 and reciprocal time constant α(α=1∕τ) of the excitation, the maximum voltage sensitivity increases, and the maximum output voltage decreases with the increase of the resonance frequency. When damping is taken into account, the output voltage of the device under pulse excitation is simply an exponentially decaying function of time. The results can be readily applied for design and fabrication of the on-.
Studies of Extragalactic Formaldehyde and Radio Recombination Lines

We present the most sensitive and extensive survey yet performed of extragalactic H2CO 6 cm (4.829 GHz) emission/absorption. Sixty-two sources were observed with the C-band system of the Arecibo Telescope to a 1 σ rms noise level of ~0.3 mJy. We report a new detection of H2CO 6 cm absorption toward NGC 520 and the confirmation of H2CO 6 cm absorption toward several sources. We report confirmation of H2CO 6 cm emission toward the OH megamasers Arp 220, IC 860, and IRAS 15107+0724. At present these are the only extragalactic H2CO 6 cm emitters independently confirmed. A characterization of the properties of formaldehyde absorbers and emitters based on infrared properties of the galaxies is discussed. We also conducted a simultaneous survey of the H110α hydrogen recombination line toward a sample of 53 objects. We report the detection of H110α toward the giant extragalactic H II region NGC 604 in M33.
Matrices, differential operators, and polynomials

It is noted that the matrix Z, of order n, defined in terms of the n arbitrary numbers xj by the formula Zjk = δjk J′l = 1,η (xj−xl)−1 +(1−δjk)(xj−xk)−1, may be considered (in an appropriate framework) to correspond to the differential operator d/dx. There follow prescriptions to construct explicit matrices of (arbitrary) order n in terms of n (or more) arbitrary numbers or of the n roots of given polynomials, matrices whose eigenvalues (and eigenvectors) are given, fully or in part, by very simple formulas. Novel representations of the classical polynomials (Hermite, Laguerre, Lagrange, Gegenbauer, Jacobi) are also obtained, such as the formula for Hermite polynomials Hn(x) = 2n det[xI−H(φ)], where I is the unit matrix (of order n) and the matrix H(φ), of order n, is defined by Hjk(φ) = (2n)−1/2(δjk(n−1)[exp(2iϑj) + 1/2 exp(−2iϑj)] +(1−δjk) {−exp(2iϑj) +2i sin(ϑj−ϑk)]−1 exp[−i(ϑj+ϑ k)]}), with ϑj = φ+πj/n, φ arbitrary.
Percentage points for a test of rank in multivariate components of variance

SUMMARY In the balanced one-way multivariate analysis of variance with random effects the likelihood ratio criterion for testing that the rank of the covariance matrix of the effect vector is not greater than a specified number is considered. The limiting distribution of -2 times the logarithm of the criterion is the distribution of the sum of squares of the positive characteristic roots of a certain random symmetric matrix. This paper presents exact and simulated quantiles of this limiting distribution for a number of cases depending on the difference between the dimensionality and the specified rank.
The American put option in a one-dimensional diffusion model with level-dependent volatility

The well-known results on the American put option problem obtained for the classical Black–Scholes model are generalized to the case of a diffusion model with level-dependent volatility. An early exercise premium representation of the value function of the American put option is established. The proof of this result is based on the properties of a stochastic integral with respect to an arbitrary continuous semimartingale over the predictable subsets of its zeros. A nonlinear integral equation is derived for the optimal exercise boundary of the American put option. The uniqueness of the solution of this integral equation is established by introducing the corresponding Cauchy problem with discontinuous right-hand side and with a unique solution in the second order Sobolev space.
Apomixis and genetic background affect distinct traits in Hieracium pilosella L. grown under competition

Apomixis, the asexual reproduction through seeds, occurs in over 40 plant families and avoids the hidden cost of sex. Apomictic plants are thought to have an advantage in sparse populations and when colonizing new areas but may have a disadvantage in changing environments because they propagate via fixed genotypes. In this study, we separated the influences of different genetic backgrounds (potentially reflecting local adaptation) from those of the mode of reproduction, i.e., sexual vs. apomictic, on nine fitness-related traits in Hieracium pilosella L. We aimed to test whether apomixis per se may provide a fitness advantage in different competitive environments in a common garden setting. To separate the effects of genetic background from those of reproductive mode, we generated five families of apomictic and sexual full siblings by crossing two paternal with four maternal parents. Under competition, apomictic plants showed reproductive assurance (probability of seeding, fertility), while offspring of sexual plants with the same genetic background had a higher germination rate. Sexual plants grew better (biomass) than apomictic plants in the presence of grass as a competitor but apomictic plants spread further vegetatively (maximum stolon length) when their competitors were sexual plants of the same species. Furthermore, genetic background as represented by the five full-sibling families influenced maximum stolon length, the number of seeds, and total fitness. Under competition with grass, genetic background influenced fecundity, the number of seeds, and germination rate. Our results suggest that both the mode of reproduction as well as the genetic background affect the success of H. pilosella in competitive environments. Total fitness, the most relevant trait for adaptation, was only affected by the genetic background. However, we also show for the first time that apomixis per se has effects on fitness-related traits that are not confounded by—and thus independent of—the genetic background.
Quasiconformal groups with small dilatation II

We study discrete quasiconformal groups with small dilatation (that is, dilatation close to 1) in n dimensions, n ≥ 3. In particular, we show that under fairly general algebraic assumptions, a discrete quasiconformal group with small dilatation is isomorphic to a discrete group of Möbius transformations. We then analyse under what conditions the algebraic isomorphism is induced by a geometric homeomorphism between the limit sets.
Fabricating optical phantoms to simulate skin tissue properties and microvasculatures

This paper introduces novel methods to fabricate optical phantoms that simulate the morphologic, optical, and microvascular characteristics of skin tissue. The multi-layer skin-simulating phantom was fabricated by a light-cured 3D printer that mixed and printed the colorless light-curable ink with the absorption and the scattering ingredients for the designated optical properties. The simulated microvascular network was fabricated by a soft lithography process to embed microchannels in polydimethylsiloxane (PDMS) phantoms. The phantoms also simulated vascular anomalies and hypoxia commonly observed in cancer. A dual-modal multispectral and laser speckle imaging system was used for oxygen and perfusion imaging of the tissue-simulating phantoms. The light-cured 3D printing technique and the soft lithography process may enable freeform fabrication of skin-simulating phantoms that embed microvessels for image and drug delivery applications.
Computational investigation of the mechanical and tribological responses of amorphous carbon nanoparticles

Nanoparticles are a class of materials that have seen increasing use as friction and wear reducers in tribological applications. Amorphous carbon (a-C) films have been the subject of significant scientific and industrial interest for use as solid-state lubricants. Here, we present classical molecular dynamics simulations to investigate the mechanical and tribological responses of a-C nanoparticles that are subjected to external forces between hydrogen-terminated diamond surfaces. Over the range of a-C nanoparticle diameters (2–5 nm) and hydrogenation (0%–50%) considered, the simulations predict a consistent mechanical response where each nanoparticle is highly elastic. The simulations predict that the transition from elastic to plastic response is directly related to an increase in the percentage of carbon-carbon crosslinking within the individual nanoparticles. Contrarily, the simulations also predict that the tribological response is noticeably impacted by changes in diameter and hydrogenation. This is .
A new robust correlation estimator for bivariate data

Key words: Outliers; robustness; iterative algoritm; computational efficiency; median product DOI: http://dx.doi. org/10.3329/bjsr.v24i2. 10766 Bangladesh J. Sci. Res. 24(2):97-106, 2011 (December)
Large-angle adjustable coherent atomic beam splitter by Bragg scattering

Using a "monochromatic" (single-axial-velocity) and slow (250 m/s) beam of metastable helium atoms, we realize up to eighth-order Bragg scattering and obtain a splitting angle of 6 mrad at low laser power (3 mW). This corresponds to a truly macroscopic separation of 12 mm on the detector. For fifth-order scattering, we have observed several oscillations of the splitting ratio when varying the laser power ("Pendellosung oscillations"). The large splitting angle, the adjustable splitting ratio, and the cleanness of the split beams, with 200- mu m rms width each, make the beam splitter ideal for a large-enclosed-area atom interferometer
Approximate inertial manifolds and effective viscosity in turbulent flows

The recently formulated concept of approximate inertial manifolds is exploited as a means for eliminating systematically the fine structure of the velocity field in two‐dimensional flows. The resulting iterative procedure does not invoke any statistical properties of the solutions of Navier–Stokes equations. It leads to a modification of those equations, such that effective viscosity‐like terms arise in a natural way. The rigorous mathematical considerations can be related to the corresponding physical concepts and intuition. The result leading to a numerical algorithm, essentially a nonlinear Galerkin method, provides a basis for large eddy simulation in which the subgrid model is derived from the properties of the Navier–Stokes equations, rather than from more or less justifiable ad hoc arguments. Some limited speculations concerning the expected results in three dimensions are also offered.
Kinetic energy control in action-derived molecular dynamics simulations

We present a computational approach to obtain classical atomic trajectories for given initial and final atomic configurations. By introducing an additional penalty function to the action of Passerone and Parrinello [Phys,Rev. Lett. 87, 108302 (2001)] the quality of atomic trajectories is greatly improved in terms of the Onsager-Machlup action. We demonstrate that this variant of the action is useful for improving path quality and consequently for atomic trajectory annealing. We utilize the one-way multigrid method as an efficient relaxation method for the construction of trajectories. The implementation of the proposed approach to a general system is quite straightforward as in the case of ordinary molecular dynamics simulations, i.e., the only requirement is to evaluate the potential energy and the atomic forces.
Positivity and nonnegativity conditions of a quartic equation and related problems

In this paper explicit conditions for positivity (no real roots), nonnegativity on positive real axis (no positive real roots with odd multiplicity), and stability aperiodicity (all roots are real, and, negative and simple) of a quartic (or biquadratic) equation are given. The derived conditions from the known solution of the quartic equation are not only complete, but simpler than those derived from Sturm, extended Hurwitz, inners, and Hankel methods. Because of Abel's Theorem (no explicit solution in terms of the roots of an equation higher than quartic exists), similar simplification for higher degree polynomial equations may not be possible. Furthermore, explicit conditions for positivity and nonnegativity of equations of higher degree than four are extremely difficult to obtain and may not be possible. The results of the paper will hopefully shed some light on a century old problem and thus enhance the engineering application of the derived condition to higher order systems.
Near-IR and visible interferometry of Be stars: Constraints from wind models

We report theoretical HI visible and near-IR line profiles, i.e. Hα (6562 A), Hβ (4861 A) and Brγ (21 656 A), and intensity maps for a large set of parameters (density, temperature, envelope geometry, inclination angle), representative of early to late Be spectral types. We have computed the size of the emitting region in the Brγ line and its nearby continuum which both originate from a very extended region, i.e. at least 40 stellar radii which is twice the size of the Hα emitting region. We predict the relative fluxes from the central star, the envelope contribution in the given lines and in the continuum for a wide range of parameters characterizing the disk models. For a density ρ = 5 10−13 g cm−3 at the base of the stellar photosphere, we obtain the largest probability of HI IR lines in emission, which is a factor of 100 lower than typical values found for Be stars. We have also studied the effect of changing the spectral type on our results and we obtain a clear correlation between the luminosity in Hα and in the infrared. We found that for a density ρ = 5 10−12 g cm−3, the probability of detecting HI IR lines in emission must be stronger for late-B spectral type stars. If no IR lines are detected for late types, it may indicate that the density in the disc is very high (∼10−11 g cm−3). On the other hand, we found that around ρ = 5 10−13 g cm−3, it is possible to have a large envelope contribution in the Brγ line and a similar or even smaller emission in the Balmer lines. Even if Brγ is formed in an extended region, it is possible to obtain a FWHM and a V/R that agree well with observed profiles. Finally, it seems that the contribution in the Brγ line increases when the envelope becomes more and more “disk-like”, contrary to the Hα and Hβ lines.
Experimental determination of the dispersion relation of light in metamaterials by white-light interferometry

We present a method to experimentally measure the complex reflection and transmission coefficients of optical waves at metamaterials under normal incidence. This allows us to determine their pertinent dispersion relation without resorting to numerical simulations. For this purpose we employ a spectrometer and a white light interferometer for amplitude and phase measurements, respectively. To demonstrate the reliability of the method, it is applied to two referential metamaterial geometries, namely, the fishnet and the double-element structure. Involved aspects of the phase measurements as well as the accuracy of the method are discussed.
Coset-based QC-LDPC codes without small cycles

A simple and efficient search method based on the coset concept is proposed to construct (3, L) quasi-cyclic low-density parity-check (QC-LDPC) codes without small cycles. Compared with the random search method, the chance to find large-girth codes is remarkably increased for the new method. Compared with Tanner's construction, the proposed method is much more flexible in the selection of row weight L. Some new codes are constructed with the shortest lengths compared with those constructed by the existing well-known methods. Simulation results show that the novel codes with moderate length perform well in the additive white Gaussian noise channel.