Miracle-dz/UniFAR-FTUs huggingface dataset:
SPATIAL STRUCTURE OF SUNSPOT OSCILLATIONS OBSERVED WITH SDO/AIA

The spatial structure of sunspot oscillations and its variation with frequency and height have been studied using data from SDO/AIA for two well-developed sunspots observed in 2010. Computation of potential magnetic fields together with line-of-sight and vector magnetograms from SDO/HMI allowed us to interpret discovered features of spatial structure. Namely, we have found that (1) expansion of the magnetic field lines above the sunspot causes a gradual broadening of the area occupied by the 3 minute oscillations with height, and (2) variation of magnetic field inclination across the sunspot causes a decrease in the pulsation frequency with distance from the center of the umbra. We have shown that the transformation from 3 minute umbral oscillations to 5 minute penumbral waves can be explained by variation of the acoustic cutoff frequency across the sunspot.
The Effect of Multicollinearity on Multilevel Modeling Parameter Estimates and Standard Errors

This study investigates the quality of multilevel model parameter estimates and standard errors as a function of varying magnitudes of correlation among Level 1 predictors and model characteristics. The results of the study showthat with multicollinearity presented at Level 1 of a two-level mixed-effects linear model, the fixed-effect parameter estimates produce relatively unbiased values; however, the variance and covariance component estimates produce downwardly biased values except for Level 1 variance (< 5%). The standard errors associated with the parameter estimates are also biased under varied magnitudes of Level 1 predictor correlation.
Self-consistent field theory for polyelectrolytes and its applications

SELF-CONSISTENT FIELD THEORY FOR POLYELECTROLYTES AND ITS APPLICATIONS SEPTEMBER 2008 RAJEEV KUMAR^B.Tech. INDIAN INSTITUTE OF TECHNOLOGY DELHI M.S. UNIVERSITY OF MASSACHUSETTS AMHERST Ph.D. UNR'ERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Murugappaii Muthukuiiiar In this work, we have de\'eloped a self-consistent field theory (SCFT) for polyelectrolytic systems and studied four important problems of contemporary interest : niicrophase separation in the melts of charged-neutral diblock copolymers, confinement effects on flexible polyelectrolytes. counterion adsorption on single flexible polyelectrolyte chain and the origin of translocation barriers in polyelectrolytic systems. Using the theory, we have been able to capture the effects of the degree of ionization, salt concentration, electrostatic and the excluded volume interaction strengths, degree of poh'merization. role of architecture and solvent quality on these polyelectrolytic systems. Within saddle-point approximation, the polyelectrolyte chain configuration is described as a walk in the presence of fields coming from the excluded volume interactions and the other effects such as incompressibility in addition to the electrostatic potential. The electrostatic potential, on the other hand, is obtained from Poisson-Boltzmann like equation. So, in contrast to the SCFT for neutral polymers.
Biased estimates of treatment effect in randomized experiments with nonlinear regressions and omitted covariates

SUMMARY Certain important nonlinear regression models lead to biased estimates of treatment effect, even in randomized experiments, if needed covariates are omitted. The asymptotic bias is determined both for estimates based on the method of moments and for maximum likelihood estimates. The asymptotic bias from omitting covariates is shown to be zero if the regression of the response variable on treatment and covariates is linear or exponential, and, in regular cases, this is a necessary condition for zero bias. Many commonly used models do have such exponential regressions; thus randomization ensures unbiased treatment estimates in a large number of important nonlinear models. For moderately censored exponential survival data, analysis with the exponential survival model yields less biased estimates of treatment effect than analysis with the proportional hazards model of Cox, if needed covariates are omitted. Simulations confirm that calculations of asymptotic bias are in excellent agreement with the bias observed in experiments of modest size.
Selection of the optimal setup policy

A model is developed taking into consideration all the costs (namely cost of sampling, cost of not detecting a change in the process, cost of a false indication of change, and the cost of readjusting detected changes) incurred when a production process, using an unscheduled setup policy, utilizes fraction-defective control charts to control current production. The model is based on the concept of the expected time between detection of changes calling for setups. It is shown that the combination of unscheduled setups and control charts can be utilized in an optimal way if those combinations of sample size, sampling interval, and extent of control limits from process average are used that provide the minimum expected total cost per unit of time. The costs of a production process that uses unscheduled setups in conjunction with the appropriate optimal control charts are compared to the costs of a production process that uses scheduled setups at optimum intervals in conjunction with its appropriate control charts. This comparison indicates the criteria for selecting production processes with scheduled setups using optimal setup intervals over unscheduled setups. Suggestions are made to evaluate the optimal process setup strategy and the accompanying optimal decision parameters, for any specific cost data, by use of computer enumeration. A numerical example for assumed cost and process data is provided.
On the Associative Analog of Lie Bialgebras

Abstract An infinitesimal bialgebra is at the same time an associative algebra and coalgebra in such a way that the comultiplication is a derivation. This paper continues the basic study of these objects, with emphasis on the connections with the theory of Lie bialgebras. It is shown that non-degenerate antisymmetric solutions of the associative Yang–Baxter equation are in one to one correspondence with non-degenerate cyclic 2-cocycles. The associative and classical Yang–Baxter equations are compared: it is studied when a solution to the first is also a solution to the second. Necessary and sufficient conditions for obtaining a Lie bialgebra from an infinitesimal one are found, in terms of a canonical map that behaves simultaneously as a commutator and a cocommutator. The class of balanced infinitesimal bialgebras is introduced; they have an associated Lie bialgebra. Several well known Lie bialgebras are shown to arise in this way. The construction of Drinfeld's double from earlier work by the author (in press, in Contemp. Math., Amer. Math. Soc., Providence) for arbitrary infinitesimal bialgebras is complemented with the construction of the balanced double, for balanced ones. This construction commutes with the passage from balanced infinitesimal bialgebras to Lie bialgebras.
ENHANCING ELECTRON EMISSION FROM SILICON TIP ARRAYS BY USING THIN AMORPHOUS DIAMOND COATING

A thin (∼2 nm thick) amorphous diamond coating was prepared on single crystal silicon tip arrays by using a filtered vacuum arc plasma deposition technique. The coating has a microscopically uniform morphology. As compared to uncoated tips, the electron emission of the coated tip arrays is enhanced, showing an increase in the total current, lower turn-on field and a lower-slope Fowler–Nordheim plot. We propose that field-emitted electrons could tunnel through such a thin coating with few scattering events. It is shown that the low potential barrier at the interface is the major cause of the enhancing effects instead of the negative surface electron affinity of the coating.
Monitoring Precipitable Water and Surface Wind over the Gulf of Mexico from Microwave and VAS Satellite Imagery

Abstract Spatial and temporal changes of atmospheric water vapor and surface wind speeds are investigated for a period following an intrusion of cold continental air over the Gulf of Mexico, during the Gulf of Mexico Experiment (GUFMEX) in March 1988. Microwave and infrared satellite measurements from the Special Sensor Microwave/Imager (SSM/I) instrument aboard the Defense Meteorological Satellite Project (DMSP) F8 satellite and from the GOES VISSR Atmospheric Sounder (VAS) are used to augment the sparse coverage of rawinsonde sites and surface reports in the vicinity of the Gulf of Mexico. Total precipitable water is derived from both instruments and from rawinsonde measurements at coastal locations and auxiliary sites on ships and platforms over the Gulf. Accuracies of the precipitable water derived from SSM/I and GOES are comparable, though microwave data provide more uniform coverage, when they are available, than VAS since they are relatively free from contamination by most clouds. Also, the moistur.
In Situ Permittivity of Canine Brain: Regional Variations and Postmortem Changes

A new probe-based measurements system was used to study dielectric properties of brain in situ, under conditions of induced physiological and pathological changes. Comparative measurements were made as function of time for 30 min prior to euthanasia and for 90-min post-mortem on the pia, the dura (both normal and anoxic), and in grey and white matter. All measurements were performed at 2450 MHz using a probe of diameter comparable to a 16-gauge hypodermic needle. Both conductivity and dielectric constant gradually decrease with time following CaCl/sub 2/ or KCI injection; however, following CaCl/sub 2/ induced cardiac arrest, values increased transiently upon injection, with subsequent decrease similar to KCI euthanasia. This indicates that the CaCl/sub 2/ injection causes a stronger and more abrupt change in blood flow to the brain, as expected from the different mechanisms by which the K/sup +/ and Ca/sup 2+/ ions cause cardiovascular arrest. Values of dielectric properties in homogenized brain--containing all tissue types--lay within the range of values recorded for different tissue types. Lower values for deeper tissue (white matter) reflect the reduced blood flow in comparison to that of the cortex (grey matter) and possible tissue differences. These regional differences are significant in determining absorption patterns for microwave exposure of the head.
The reception of Frege in Poland

This paper examines how the work of Frege was known and received in Poland in the period 1910–1935 (with one exception concerning the later work of Suszko). The main thesis is that Frege's reception in Poland was perhaps faster and deeper than in other countries, except England, due to works of Russell and Jourdain. The works of Łukasiewicz, Leśniewski and Czeżowski are described.
ADDITIVE SUBGROUPS GENERATED BY POLYNOMIAL VALUES ON RIGHT IDEALS

Let R be a prime ring with extended centroid C, ρ a nonzero right ideal of R and f(X 1,…,Xt ) a nonzero polynomial over C. We determine the additive subgroup of RC generated by all elements f(x 1,…,xt ) for x 1,…,xt ∈ ρ C and obtain a result concerning an independence property of polynomials in prime rings.
Asymptotic behaviour of some nonlocal diffusion problems

We deal with a parabolic equation having a diffusion coefficient depending on a nonlocal quantity. We investigate the convergence of the solution towards a steady state, extending previous results obtained by [M. Chipot and B. Lovat (1999). On the asympotic behaviour of some nonlocal problems. Positivity, 3, 65-81]. Using the dynamical systems point of view, we are able to treat the case of a continuum of steady states
The Statistical Mechanics of Phase Transitions

Abstract This article traces the development and study of phase transitions from late last century to the present day. We begin with a brief historical sketch and a description of the statistical mechanics of phase transitions. Particular attention is given to the modern era which began in 1944 with Onsager's celebrated solution of the two-dimensional Ising model. Points of development since Onsager, which are highlighted in this article, include the study of critical exponents, the scaling hypothesis, realisation of the universality of critical exponents and the recent renormalization group approach to critical phenomena. The basic idea of the renormalization group method, rather than the detailed application of the recipe to particular cases, is stressed and is discussed critically in some detail.
Geometry and physical conditions in the stellar wind of AG Carinae

AG Carinae is one of the prototypes of the class of Luminous Blue Variables (LBVs). Since 1990 the star has continuously brightened in its visual continuum. We report on a multi-instrument and -wavelength observing campaign to monitor the current activity phase of AG Car. Ground-based photometry, polarimetry, spectroscopy, and space-ultraviolet spectroscopy and spectropolarimetry have been obtained. From the variability of the polarization at ultraviolet and optical wavelengths we detect significant intrinsic polarization. P(sub int) greater than or equal to 0.5% is a large value for a hot, luminous star, suggesting departure from spherical symmetry in the wind of AG Car. The intrinsic polarization is variable on a timescale of 2 months or less. The measured ultraviolet polarization (intrinsic + interstellar) dropped to 0.5% in 1992 May and returned to 1% in 1992 July. The results are interpreted in terms of a variable outflow with a density enhancement in the equatorial plane. A similar model was suggested for the related object R127 in the Large Magellanic Cloud (LMC). This geometry is reminiscent of the large-scale morphology of the gas nebula and dust 'jet' surrounding AG Car. It is therefore likely that physical conditions close to the stellar surface are responsible for the geometry of the spatially resolved circumstellar material around AG Car. Despite the drastic change of the photospheric conditions, the mass-loss rate did not increase. We find no evidence for a positive correlation between wind density and stellar radius. This makes models that explain the radius increase by opacity effects in the outflow unlikely. The mechanism responsible for the temperature and radius variations is still unknown but most likely has its origin in subphotospheric regions.
The Gas Drag Effect on the Elliptic Motion of a Solid Body in the Primordial Solar Nebula

The gas drag effect in the primordial solar nebula on the motion of a solid body, ranging from a large planetesimal to a small dust grain, is investigated. For a planetesimal, expressions for the short-term variation of the semi-major axis, the eccentricity and inclination are obtained using a perturbation method and a realistic formula for the gas drag force. For a small body, an orbit spiralling towards the sun in the equatorial plane of the nebula is investigated and the decay time of the orbital radius is obtained. It is found that the decay time at 1 a.u. is as short as 10' or 10' years for a solid body with mass in the range between 10' g and 10' g.
Contrail coverage derived from 2001 AVHRR data over the continental United States of America and surrounding areas

Linear contrail coverage, optical depth, and longwave radiative forcing are derived from NOAA-15 and NOAA-16 Advanced Very High Resolution Radiometer data taken during daytime over the continental United States of America (USA), southern Canada, northern Mexico, and the adjacent oceans. Analyses were performed for all available overpasses during 2001, but for NOAA-15 were primarily limited to the eastern half and the northwestern corner of the domain. Contrail coverage averaged 1.17 % and 0.65 % from the early morning NOAA-15 and midafternoon NOAA-16, respectively, for the areas and month common to both satellites. The NOAA-16 contrail coverage and radiative properties for the limited NOAA-15 domain are, on average, nearly identical to those for the entire domain. The estimated combined maximum coverage for the entire domain was ∼1.05 % during February, while the minimum of 0.57 % occurred during August. Mean optical depths varied by ∼ 20 % with winter minima and summer maxima. The annual mean optical depth of 0.27 translated to a normalized contrail longwave radiative forcing of 15.5 Wm -2 . The overall daytime longwave radiative forcing for the domain is 0.11 Wm -2 . The normalized radiative forcing peaked during summer while the overall forcing was at a maximum during winter because of the greater contrail coverage. A detailed error analysis showed that the linear contrail coverage was overestimated by ∼40 % for both satellites the true coverage is closer to 0.70 and 0.40 % for NOAA-15 and 16, respectively. Errors in the mean NOAA-15 optical depths and radiative forcing were negligible while their NOAA-16 counterparts were overestimated by approximately 13 %. Contrail coverage was dramatically lower than expected from previous studies, but is most likely due to the significant decrease in upper tropospheric humidity observed in numerical weather analysis data. Contrail optical depths are much greater than both theoretical estimates for this part of North America and empirical retrievals over Europe. The cause of the morning-afternoon difference in contrail coverage is not yet known. Further modelling studies and additional satellite analyses are needed to understand this diurnal cycle and to explain the differences between the present and previous results.
2D reconstruction of biological tissues polycrystalline structure by analyzing Mueller-matrix singular images

The paper deals with investigating the processes of laser radiation transformation by biological liquid crystals networks using the singular optics techniques. The results obtained showed a distinct correlation between the points of "characteristic" values of coordinate distributions of Mueller matrix (Mik = 0 , ±1) elements and polarization singularities (S- and C-points) of laser speckle field. The technique of Muellermatrix singular diagnostics of pathological changes skin derma tissue.
Coherence estimation method and its application to phase unwrapping

Coherence of interferometric synthetic aperture radar (InSAR) complex image pair is a fundamental observable in interferometric radar measurements, which is usually measured by comparing the radar return across several nearby radar image pixels and has found diverse applications. This paper proposes a coherence estimation method which requires three arbitrary parts of the two complex images to implement interference. The proposed method can also be used to co-register InSAR image pair, which means that the imaginary part of the master image can be left away. In addition, an improved quality-guided phase unwrapping method is forwarded with the quality map generated by the coherence estimation method we have recommended above. A look-up table is adopted to reduce the processing time. The experimental results show that both methods are effective and greatly reduce the phase unwrapping time compared with the existing quality-guided methods.
Approximate feedback linearization around a trajectory: application to trajectory planning

In this paper, we consider the approximate feedback linearization of a nonlinear system with one input in a neighborhood of a trajectory. We obtain a normal form for the dynamics in a neighborhood of a given trajectory. The normal form can be used to find a more aggressive trajectory in a vicinity of the original trajectory. The process can be repeated several times, yielding an iterative procedure for designing aggressive trajectories. An example is given to illustrate the approach.
Spreading of partially coherent flattened Gaussian beams propagating through turbulent media

Based on the extended Huygens–Fresnel principle, the spreading of partially coherent flattened Gaussian beams propagating through turbulent media is studied by using the incoherent superposition of higher-order Hermite–Gaussian beams. The mean-squared width of partially coherent flattened Gaussian beams in turbulence is derived. It is shown that the spreading of partially coherent flattened Gaussian beams increases with increasing turbulent parameter and beam order N. However, the difference between the relative spreading of partially coherent flattened Gaussian beams in turbulent media and in free space reduces as N increases. Therefore, partially coherent flattened Gaussian beams with high N are less sensitive to the effects of turbulence than those with lower N.
3. Validation of a Diary Measure of Children's Physical Activities

This study compares levels of physical activity of 9–14-year-old children from a self-reported time diary with those measured using an accelerometer. Children (N=92) wore an accelerometer for one weekend day and completed a 24-hour time diary for that day. The time children spent in moderate to vigorous physical activity from time diaries was moderately highly correlated with the measured results. Self-reported and objective measures of in tensity were correlated, but the correlation varied substantially by activity and characteristics of the family. This study provides empirical evidence to support the validity of time-diary estimates when accelerometer data are not available.
Logistic regression with incompletely observed categorical covariates: A comparison of three approaches

SUMMARY A logistic regression analysis based on the complete cases neglects the information due to subjects with missing values in at least one but not in all covariates. Three different approaches allowing the use of this information are compared: maximum likelihood estimation, pseudo maximum likelihood estimation, and probability imputation. The first two yield consistent estimates of the regression coefficients and asymptotic normality allows the construction of asymptotically valid confidence intervals. The only necessary assumption is that the probability for the occurrence of missing values does not depend on the true value of the hidden covariates, whereas there may be a dependence on completely observed covariates and on the outcome variable. Their relative efficiency and the gain relative to a complete case analysis is investigated. Comparison with imputation methods shows that imputation of conditional probabilities can be regarded as a close approximation to the pseudo maximum likelihood estimation, whereas imputation of unconditional probabilities is associated with serious bias.
3He refrigerator based very low temperature scanning tunneling microscope

We describe the design and development of a scanning tunneling microscope (STM) which can operate at temperatures down to 240 mK and in magnetic fields up to 7 T with high spatial and energy resolution. The compact and rigid STM head is mounted directly on a low vibration, single shot, 3He refrigerator. This refrigerator can be operated at its base temperature continuously for several days before the 3He needs to be recondensed. The system is equipped with a sample transport manipulator from room temperature, and a cleavage device at low temperature, so that the cryogenic ultrahigh vacuum condition inside the cryostat can be utilized. A superconducting magnet provides a magnetic field of up to 7 T at the sample along the STM tip direction. Test results have shown that, at the base temperature, this instrument has better than 0.5 pm z-direction resolution in imaging mode, and better than 20 μV energy resolution in spectroscopy mode.