Miracle-dz/UniFAR-FTUs huggingface dataset:
Imaging of high-speed dust particle trajectories on NSTX

Imaging of high-speed incandescent dust particle trajectories in a tokamak plasma has been accomplished on NSTX using up to three high-speed cameras each viewing the same plasma volume from different locations and operating at speeds up to 68000frames∕s with exposure times varying from 2to300μs. The dynamics of the dust trajectories can be quite complex exhibiting a large variation in both speed (10–200m∕s) and direction. Simulations of these trajectories will be utilized to ascertain the role dust may play in future machines such as ITER where significant dust production from wall erosion is expected. NSTX has numerous view ports including both tangential as well as radial views in both the midplane and lower divertors. Several vertical ports are also available so that a few specific regions in NSTX may be viewed simultaneously from several different camera positions. The cameras can be operated in the full visible spectrum but near-infrared filters can be utilized to enhance the observation of incandesc.
Who Are the Gypsies?

Charles G. Leland, who, as is well known, has made special studies of the Gypsies and their language, contributes an illustrated paper to the April Cennury on “ Visiting the Gypsies,” from which we quote the following : In conclusion, I may briefly answer a question which many per­ sons have put, “ Who and what are the Gypsies ? ” To this, I reply that they are of a mixed Aryan and non-Aryan stock from Northern India, where they have been known since prehistoric times. In their own language they call themselves Rom, meaning husband ; but the word may also have some affinity with ramna, meaning to roam or wander. I believe that I have been the first to prove that there is at the present day in India, among the one hun­ dred and fifty kinds of wandering castes of that country, which are all Gypsies, one in particular which is there regarded as specially Gypsy, and which calls itself Rom, and which uses words not col­ lected in any other Indian dialect, but which are used by the Gypsies of Syria, Turkey and Europe. This tribe is allied to, and is most probably only a more widely wandering branch of the Dom, who are also known as outcasts and Gypsies. When I speak of so many kinds of wanderers as Gypsies, and yet not identical with our own, I may make my meaning clearer by saying, that as all the tramps, peddlers, etc., who roam in our roads are still not Romany, so of all the Indian nomads, there is but one which in every particular, especially that of language, exactly corresponds to those whom I have described.
Differentially Private Ordinary Least Squares: $t$-Values, Confidence Intervals and Rejecting Null-Hypotheses

Linear regression is one of the most prevalent techniques in data analysis. Given a large collection of samples composed of features $\vec x$ and a label $y$, linear regression is used to find the best prediction of the label as a linear combination of the features. However, it is also common to use linear regression for its \emph{explanatory} capabilities rather than label prediction. Ordinary Least Squares (OLS) is often used in statistics to establish a correlation between an attribute (e.g. gender) and a label (e.g. income) in the presence of other features. Under the assumption of a certain random generative model for the data, OLS derives \emph{$t$-values} --- representing the likelihood of each real value to be the true correlation in the underlying distribution. Using $t$-values, OLS can release a \emph{confidence interval} that is likely to contain the true correlation. When this interval does not intersect the origin, we can \emph{reject the null hypothesis} as it is likely that $x_j$ indeed has a non-zero correlation with $y$. Our work aims at achieving similar guarantees on data under differentially private estimators. We use the Gaussian Johnson-Lindenstrauss transform, which has been shown to satisfy differential privacy if the given data has large singular values. We analyze the result of projecting the data using JLT under the OLS model and derive approximated $t$-values, confidence intervals and bound the number of samples needed to reject the null hypothesis when the data is drawn i.i. d from a multivariate Gaussian. When not all singular values of the data are sufficiently large, we increase the singular values, thus our projected data yields an approximation for the Ridge Regression problem. We derive, under certain conditions, confidence intervals in this case as well. We also derive confidence intervals for the "Analyze Gauss" algorithm of Dwork et al.
Thunder-storms and the penetrating radiation

The possibility of a connection between thunder-storms and the penetrating radiation was first suggested by C. T. R. Wilson, who pointed out that the powerful fields within thunder-storms should exert an important accelerating effect upon β-particles produced by the disintegration of the radioactive material carried in the air. He showed that many of these particles should gain far more energy from the field in traversing a given distance than they lost in ionisation, and that they might thus acquire a very considerable fraction of the energy corresponding to the fall of potential, of the order of 109 volts, between the poles of the cloud. He examined the effect of close encounters of these accelerated particles with atomic electrons, resulting in the ejection of fast secondary particles, and also the action of ordinary nuclear scattering, and found that neither of these would seriously interfere with the accelerating process. The secondary electrons, indeed, would often be emitted with sufficient energy and in a suitable direction to be accelerated themselves. An occasional encounter with an atomic nucleus at a distance at which the inverse square law of force failed to hold would be the only possible manner in which the process might be stopped, but such an encounter would be so rare that the β-particle would have acquired a very considerable amount of energy before it occurred and this might be radiated as a penetrating γ-ray quantum. "The general effect of an accelerating field is that a β-particle, instead of dying as it were a natural death by gradual loss of energy, is continually acquiring more and more energy and increasing its chance of surviving all accidents other than direct encounters with the nuclei of atoms. " In this paper these accelerated particles will be referred to as runaway electrons, a description first applied to them by Eddington. Interest in this suggestion, which, as Wilson pointed out, might bear on the question of the origin of part at least of the penetrating radiation, is heightened by the fact that recent estimates of the energy of this radiation considered either as γ- or β-rays give results of the order of 109 e. -volts.
Compact hard X-ray grating interferometry for table top phase contrast micro CT

Today’s commercial X-ray micro computed tomography (CT) specimen systems are based on microfocus sources, 2D pixel array cameras and short source-to-detector distances (i.e. cone-beam configurations). High resolution is achieved by means of geometric magnification. The further development of such devices to acquire phase and scattering contrast images can dramatically enhance their range of applications. Due to the compact geometries, which imply a highly diverging beam, the gratings must be curved to maintain highest imaging performance over a large field of view. We report about the implementation of extremely compact Talbot and Talbot- Lau type grating interferometers which are compatible to the geometry of typical micro CT systems. For the analytical description of the imaging system, formulas are presented describing the dependency of the sensitivity on geometric parameters, camera and source parameters. Further, the imaging pipeline consisting of the data acquisition protocol, radiographic phase retrieval and tomographic image reconstruction is illustrated. The reported methods open the way for an immediate integration of phase and scattering contrast imaging on table top X-ray micro CT scanners.
A critique of neural networks for discrete-time linear control

This paper discusses the use of multi-layer perceptron networks for linear or linearizable, adaptive feedback.control schemes in a discrete-time environment. A close look is taken at the model structure selected and the extent of the resulting parametrization. A comparison is made with standard, non-perceptron algorithms, e.g. self-tuning control, and it is shown how gross over-parametrization can occur in the neural network case. Because of the resultant heavy computational burden and poor controller convergence, a strong case is made against the use of neural networks for discrete-time linear control.
What do we really know about the magnetic fields of the Milky Way?

Abstract We have several methods of measuring magnetic fields in the Milky Way. We can study optical polarization, radio polarization, rotation measures of pulsars and extragalactic radio sources as well as include Zeeman results. Each of the above mentioned methods was at times used to make a model of the magnetic fields of the Milky Way. However one or two of the data sets by themselves cannot tell us the whole story. Any model of the magnetic fields must be able to fit all the observational results. At the present time a lot of progress has been made. We have increased our data bases in most of the observational areas. However a robust model of the magnetic field of the Milky Way has not yet emerged. We must possibly wait to the era of SKA.
Utilizing nonlinear optical properties of nanoparticles for imaging and sensing

Nonlinear optical properties of barium titanate (BaTiO3) nanoparticles are investigated as a function of size and shape. BaTiO3 is an attractive option as a nonlinear material because it can exhibit a high second and third order electronic susceptibility even at the nanoscale. These particles are employed as contrast agents/biomarkers and phase conjugate nanomirrors in imaging, utilizing second harmonic generation for two-photon microscopy and four-wave mixing for three-photon microscopy and scattering reversal image enhancement. Silver is also used to create a shell around the BaTiO3 nanoparticle to see if a core/shell structure enhances any of the nonlinear effects.
Design of linear-phase IIR digital filters using singular perturbational model reduction

A new technique for the design of a passband linear-phase infinite impulse response (IIR) digital filter is presented. This technique is based on computing orthonormal bases, which span the left and right invariant subspaces associated with the large and small eigenvalues of the cross-Gramian matrix W/sub c0/, which tends to be symmetric and easily constructed. The orthonormal bases are computed by using the ordered real Schur form decomposition, which has been proved to be robust and numerically stable. The proposed technique is illustrated by several examples.
EXTENDED LIGHT CURVES FOR NOVA CYGNI 1978.

Differential magnitudes of Nova Cygni 1978 observed with a wide Hβ (w) filter are presented over a period of 829 days following the event, along with terminal values of Strömgren y. The y (continuum) and w (Hβ and [O III] emission + continuum) light curves rapidly separate, with w over four magnitudes brighter than y by day 311, by which time the star appears to have returned to minimum. The decay in the nebular radiation in magnitude vs. time is linear from at least day 432 onward, with an exponential decay time of 220 days. The data provide a constraint on theoretical models of the development of the star with its expanding nebula.
A study of planar Richtmyer-Meshkov instability in fluids with Mie-Grüneisen equations of state

We present a numerical comparison study of planar Richtmyer-Meshkov instability with the intention of exposing the role of the equation of state. Results for Richtmyer-Meshkov instability in fluids with Mie-Gruneisen equations of state derived from a linear shock-particle speed Hugoniot relationship (Jeanloz, J. Geophys. Res. 94, 5873, 1989; McQueen et al., High Velocity Impact Phenomena (1970), pp. 294–417; Menikoff and Plohr, Rev. Mod. Phys. 61(1), 75 1989) are compared to those from perfect gases under nondimensionally matched initial conditions at room temperature and pressure. The study was performed using Caltech’s Adaptive Mesh Refinement, Object-oriented C++ (AMROC) (Deiterding, Adaptive Mesh Refinement: Theory and Applications (2005), Vol. 41, pp. 361–372; Deiterding, “Parallel adaptive simulation of multi-dimensional detonation structures,” Ph.D. thesis (Brandenburgische Technische Universitat Cottbus, September 2003)) framework with a low-dissipation, hybrid, center-difference, limiter patch solver (Ward and Pullin, J. Comput. Phys. 229, 2999 (2010)). Results for single and triple mode planar Richtmyer-Meshkov instability when a reflected shock wave occurs are first examined for mid-ocean ridge basalt (MORB) and molybdenum modeled by Mie-Gruneisen equations of state. The single mode case is examined for incident shock Mach numbers of 1.5 and 2.5. The planar triple mode case is studied using a single incident Mach number of 2.5 with initial corrugation wavenumbers related by k_1 = k_2+k_3. Comparison is then drawn to Richtmyer-Meshkov instability in perfect gases with matched nondimensional pressure jump across the incident shock, post-shock Atwood ratio, post-shock amplitude-to-wavelength ratio, and time nondimensionalized by Richtmyer’s linear growth time constant prediction. Differences in start-up time and growth rate oscillations are observed across equations of state. Growth rate oscillation frequency is seen to correlate directly to the oscillation frequency for the transmitted and reflected shocks. For the single mode cases, further comparison is given for vorticity distribution and corrugation centerline shortly after shock interaction. Additionally, we examine single mode Richtmyer-Meshkov instability when a reflected expansion wave is present for incident Mach numbers of 1.5 and 2.5. Comparison to perfect gas solutions in such cases yields a higher degree of similarity in start-up time and growth rate oscillations. The formation of incipient weak waves in the heavy fluid driven by waves emanating from the perturbed transmitted shock is observed when an expansion wave is reflected.
Model of defect diffusion and development of the boson peak in an amorphous solid

A schematic model is proposed for understanding the boson peak as a consequence of the coupling between slowly decaying density fluctuations and the transverse sound modes that develop in the amorphous solid. The present analysis demonstrates that the nature of the dynamics of defect densities in the disordered system plays a crucial role for the appearance of the peak. We compare the results for the dynamic structure factor with the scattering data of Sokolov et al. [J. Non-Cryst. Solids 172-174, 138 (1994)]. With the relaxation time for the defects becoming longer which is the case more appropriate for the strong glasses as compared to the fragile glasses where structural degradation occurs more easily, the boson peak become more pronounced.
β-tricalcium phosphate/gelatin composite scaffolds incorporated with gentamycin-loaded chitosan microspheres for infected bone defect treatment

The repair of infected bone defects remains a clinical challenge. Staphylococcus aureus is a common pathogenic micro-organism associated with such infections. Gentamycin (GM) is a broad spectrum antibiotic that can kill S. aureus in a dose-dependent manner. However, the systemic administration of antibiotics may lead to drug resistance and gut dysbiosis. In this work, we constructed β-tricalcium phosphate/gelatin composite scaffolds incorporated with gentamycin-loaded chitosan microspheres (CMs(GM)-β-TCP/gelatin composite scaffolds), which helped optimize the local GM release in the infected defect areas and enhance bone regeneration. The cumulative release curves showed that both microspheres and composite scaffolds reached a sustained slow-release phase after the initial rapid release, and the latter further stabilized the initial drug release rate. The release curve of CMs(GM)-β-TCP/gelatin composite scaffolds reached a plateau after 24 h, and the cumulative release reached 41.86% during this period. Moreover, the combination of β-TCP and gelatin mimicked bone composition and were able to provide the requisite mechanical strength (0.82 ± 0.05 MPa) during the first phase of bone generation. The inner structure of the scaffold was arranged in the shape of interconnected pores, and presented a porosity level of 16%. The apertures were uniform in size, which was beneficial for cell proliferation and material transportation. Macroscopic observation and histological analysis showed that CMs(GM)-β-TCP/gelatin composite scaffolds fused with bone tissues, and new tissues were formed in defect areas without any infection. This new composite scaffold may be a promising repair material for treating infected bone defects.
A comparison among various PMD mitigation approaches

The proposed methods of Polarization Mode Dispersion (PMD) mitigation can be divided into three main approaches: (i) electrical PMD compensation, (ii) optical PMD compensation, and (iii) mitigation by use of robust modulation formats, increased power margin etc. In this paper, we discussed each of these sententiously, with less emphasis on comparing the first and the second, but with more emphasis on the third. We quantify the benefits of using different techniques for compensation of PMD in fiber-optic communication systems by means of numerical simulations. This is done both with respect to PMD-induced pulse broadening and in terms of system outage probability for different data formats [nonreturn-to-zero (NRZ) and return-to-zero (RZ)]. With our experimental results, we find that RZ performs better than NRZ, furthermore, it is comparable with 2-3 DOF PMD compensator, and can be expected to be a practical alternative in particular if used in combination with error correcting codes. We also study the trade-off between power margin and acceptable PMD. Moreover, it is generally believed that a PMD compensator with a polarization controller and a variable delay line can only compensate the PMD to the first order. Our experimental results show that, the counterintuitive fact that this scheme can also partially compensate for higher order PMD. We also investigate the benefit of using a polarizer as compensation element where the optical average power can be used as a feedback signal.
K(2)O(2): The most stable oxide of K

We have analyzed the stability of various oxides of K and find that K(2)O(2) is the most stable one. The additional stability is traced to the presence of oxygen dimers in K(2)O(2) which interact to form molecular orbitals. Other oxides such as KO(2) and KO(3) which also have dimers/trimers of oxygens are found to be less stable. This is traced to the shorter O-O bonds that one finds in them which gives rise to a significant coulomb repulsion between the electrons on the oxygen atoms making up the dimer/trimer, making them less stable.
A simple predictive density based on the p*-formula

The predictive density proposed by Harris (1989) is based on integrating the density for a new observation with respect to the estimated sampling distribution of the maximum likelihood estimator of the unknown parameter. This has good properties, but is rather complicated to compute even for simple models. An approximation to the Harris proposal is considered which consists of approximating the sampling distribution of the maximum likelihood estimator of the unknown parameter by Barndorff-Nielsen's (1983) p * -formula, and then using a Laplace approximation with O(n -1 ) correction terms for integrating out the parameter. The result can generally be expressed in terms of standard likelihood derivatives, and takes a quite simple form for exponential families and for location models.
Solar minimum streamer densities and temperatures using Whole Sun Month coordinated data sets

We model electron densities of the simplest, most symmetric solar minimum streamer structure observed during the Whole Sun Month (WSM) campaign, using coronal observations of both visible white light and extreme ultraviolet (EUV) emission. Using white light data from the SOHO/LASCO/C2 and HAO/Mauna Loa Mark 3 coronagraphs, we determine electron densities by way of a Van de Hulst inversion. We compare the white light densities to those determined from the density sensitive EUV line ratios of Si IX 350/342 A observed by the SOHO/coronal diagnostic spectrometer (CDS). Moreover, from the white light density profiles we calculate hydrostatic temperature profiles and compare to temperatures derived from the Si XII/Mg X line ratio. We find the white light and spectral analysis produce consistent density and temperature information.
Right inverse of a discrete time non-linear system

The concept of right invertibility (functional reproducibility) of a general multi-variable discrete time analytic non-linear system is discussed. Two different types of right inverses are considered, one being a special case of the other. The sufficient conditions for both types of right invertibility are given and for invertible systems the right inverses are constructed.
Forced oscillations in nearly sinusoidal systems

A large class of radio circuits which are analytically equivalent to an oscillatory network in parallel with a non-linear negative resistance, are represented fairly accurately by the differential equation v? (? +sv? v2)v + ? 2v = E? 21 sin? 1t where, ? /? , s/? , ? /? are small. The behaviour of the solutions of this equation near resonance has been discussed by Appleton, van der Pol and others. The paper contains a more complete discussion of the synchronized and quasi-periodic solutions near resonance, their phases, amplitudes and energy, and also the way in which one type of stable solution gives way to another as the parameters of the system vary, for instance as the electromotive force or detuning vary. It is shown that the phase and amplitude favourable to synchronization are prolonged just before synchronization. This agrees with Appleton's experimental results. It is also found that hysteresis occurs. The decrease in energy with the decrease in detuning is explained by the fact that the phase favourable to synchronization is that which opposes the motion and is prolonged.
The other biodiversity record: Innovations in animal-substrate interactions through geologic time

Tracking biodiversity changes based on body fossils through geologic time became one of the main objectives of paleontology in the 1980s. Trace fossils represent an alternative record to evaluate secular changes in diversity. A quantitative ichnologic analysis, based on a comprehensive and global data set, has been undertaken in order to evaluate temporal trends in diversity of bioturbation and bioerosion structures. The results of this study indicate that the three main marine evolutionary radiations (Cambrian Explosion, Great Ordovician Biodiversification Event, and Mesozoic Marine Revolution) detected in the body-fossil record are also expressed in the trace-fossil record. Analysis of ichnodiversity trajectories in marine environments supports Sepkoski’s logistic model, which was originally based on analysis of marine body fossils. The tracefossil record of continental environments suggests variable rates of increases in ichnodiversity, with major radiations in the Ludlow–Early Devonian, Cisuralian, Early Jurassic, Late Cretaceous, and Eocene, and slower increases or plateaus in between these periods. Our study indicates that ichnologic information represents an independent line of evidence that yields valuable insights to evaluate paleobiologic megatrends.