Miracle-dz/UniFAR-FTUs huggingface dataset:
A self-consistent fully turbulent theory of auroral E region irregularities

We present a nonlinear theory of high-latitude E region irregularities that is based solely on the effects of mode coupling on the turbulent state of the plasma. We have been using a nonlinear equation based on a two-fluid model governing the evolution of ion acoustic turbulence in the absence of k∥ = k · B0/B0 effects. We have first shown that the linear eigenmodes cannot be used as a zeroth-order approximation to describe the often-seen strongly turbulent high-latitude E region plasma waves. However, with the assumption of weakly growing or decaying nonlinear modes with broad frequency spectra (quasi-steady state turbulence), we have been able to obtain a set of constraints on the mean frequency and spectral width of both linearly stable and linearly unstable modes. With the use of an “eddy damped quasi-normal Markovian” closure scheme for the spectral density and a self-consistent expression for the frequency broadening and the nonlinear growth rate, we have been able, as a result, to relate the Doppler width of radar spectra to the broadband density fluctuation level. Our estimates have led us to believe that strongly turbulent conditions are associated with broadband fluctuation levels of the order of 5 to 10%, no more, in the situations of interest. Our closure scheme also produces a specific set of nonlinear coupled equations that could be solved numerically in order to derive spectral laws pertinent to high-latitude E region turbulence.
Non-Local Theory Solution of Two Mode-I Collinear Cracks in the Piezoelectric Materials

In this paper, the non-local theory is applied to obtain the behavior of two collinear cracks in the piezoelectric materials subjected to a uniform tension loading. The permittivity of air in the crack is considered. By means of the Fourier transform, the problem can be solved with the help of two pairs of triple integral equations, in which the unknown variables are the jumps of the displacements across the crack surfaces. To solve the triple integral equations, the jumps of the displacements across the crack surfaces are expanded in a series of Jacobi polynomials. Numerical examples are provided to show the effects of the interaction of two cracks, the materials constants, the electric boundary conditions and the lattice parameter upon the stress and the electric displacement fields near the crack tips. It can be obtained that the effects of the electric boundary conditions upon the electric displacement fields are large. Unlike the classical piezoelasticity solutions, it is found that no stress and electric displacement singularities are present at the crack tips. The non-local elastic solutions yield a finite hoop stress at the crack tips, thus allowing us to use the maximum stress as a fracture criterion.
Review papers : The statistical basis of meta-analysis

Two models for study-to-study variation in a meta-analysis are presented, critiqued and illustrated. One, the fixed effects model, takes the studies being analysed as the universe of interest; the other, the random effects model, takes these studies as representing a sample from a larger population of possible studies. With emphasis on clinical trials, this paper illustrates in some detail the application of both models to three summary measures of the effect of an experimental intervention versus a control: the standardized difference for comparing two means, and the relative risk and odds ratio for comparing two proportions.
Zonal-flow-driven nonlinear energy transfer in experiment and simulationa)

Using a newly developed algorithm, the nonlinear transfer of internal fluctuation energy ∣n∣2 due to convection of drift-wave turbulence by a geodesic acoustic mode (GAM, a finite-frequency zonal flow) has now been measured directly in a high-temperature plasma. By combining spatially resolved density fluctuation measurements obtained via an upgraded beam emission spectroscopy system in the edge region of the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] with a velocity inference algorithm, the convection of turbulent fluctuations by the GAM has been measured. Taken together, the results strongly suggest that GAM convection of turbulence leads to a transfer of internal fluctuation energy from low to high frequencies, in agreement with expectations from theory and simulation. In addition, the GAM is found to modulate the intensity of the density fluctuations. Calculations of the measured nonlinear interactions in the gyrokinetic code GYRO are found to be in good qualitative agreement with the .
Many-particle effects in type II quantum dots

Many-particle effects are investigated in the photoluminescence of type II GaSb/GaAs quantum dots (QDs). With increasing excitation density, i.e., exciton occupation, the photoluminescence shows first a blueshift and then saturates developing a plateau region. The peculiar behavior is attributed to Coulomb charging and state filling of the localized holes to dominate the many-particle regime. A high temperature stability makes the GaSb/GaAs QDs suitable for room-temperature devices.
A test for normality based on the empirical characteristic function

SUMMARY An omnibus test of normality is proposed, which has high power against many alternative hypotheses. The test uses a weighted integral of the squared modulus of the difference between the characteristic functions of the sample and of the normal distribution. together with the one-to-one correspondence between +(t) and F(x), suggest utilizing kn(t) in statistical inference. Here we use /n(t) to test the composite hypothesis that F(x) is normal. Let 00(t) = exp (it1 - 1t2 a2) be the characteristic function under the null hypothesis, with 1u and U2 the unspecified mean and variance. The test introduced here is based on a weighted integral over t of the squared modulus of kn(t) - $O(t), where $0(t) depends on sample estimates of ju and a2. We compare the power of the test with that of prominent tests based on order statistics and on sample moments. Heathcote (1972) and Feigin & Heathcote (1977) have previously considered using either the real or imaginary part alone of 4n(t) in tests of simple hypotheses. Their tests relied on the fact that, for given t, either component of 4n(t) is asymptotically normal with mean given by its population counterpart. If the alternative hypothesis is also simple, it may be possible to find a value of t that maximizes the power of the test in large samples. Epps, Singleton & Pulley (1982) showed how the sample moment generating function may be employed to test composite hypotheses that the data come from one or the other of two separate families of distributions. Murota & Takeuchi (1981) have recently proposed a location and scale invariant test based on the statistic -an(t) = I n(t/S) 12, where S is the sample standard deviation. Applied to the problem of testing normality, an(t) was found to have high power in the vicinity of t = 10 against members of six families of symmetric alternatives, but its
The enstrophy equation budget of bounded turbulent shear flows

The turbulent enstrophy equation budget for a fully developed two‐dimensional channel flow computed from a direct numerical simulation is compared to that for a flat plate boundary layer flow obtained experimentally. A close agreement is found between the comparable terms in the enstrophy equation suggesting that there probably is common behavior for the enstrophy budget in wall bounded flows.
Three-dimensional simulations of protostellar jets

We present the first results of fully three-dimensional (3D) simulations of supersonic, radiatively cooling jets using the smoothed particle hydrodynamics technique (SPH). Our results qualitatively agree with the two-dimensional (2D) simulations of Blondin, Fryxell, & Konigl (1990), although the removal of the axisymmetry has resulted in relevant structural differences, especially at the jet head where a cold shell is formed from the condensation of shock-heated material. In particular, we found that the shell is not only dynamically unstable but also may undergo oscillations in density, which are attributed to global thermal instabilities. These effects may have important consequences on the dynamics and emission pattern of the observed HH objects associated to young stellar jets
Comparison Between Steady and Unsteady Double-Entry Turbine Performance Using the Quasi-Steady Assumption

The experimental performance evaluation of a circumferentially divided, double-entry turbocharger turbine is presented in this paper with the aim of understanding the influence of pulsating flow. By maintaining a constant speed but varying the frequency of the pulses, the influence of frequency was shown to play an important role in the performance of the turbine. A trend of decreasing cycle-averaged efficiency at lower frequencies was measured. One of the principal objectives was to assess the degree to which the unsteady performance differs from the quasi-steady assumption. In order to make the steady-unsteady comparison for a multiple entry turbine, a wide set of steady equal and unequal admission flow conditions were tested. The steady state data was then interpolated as a function of three, non-dimensional parameters in order to allow a point-by-point comparison with the instantaneous unsteady operation. As an average, the quasi-steady assumption generally under-predicted the mass flow and efficiency loss through the turbine, albeit the differences were reduced as the frequency increased. Out-of-phase pulsations produced unsteady operating orbits that corresponded to a significant steady state, partial admission loss, and this was reflected as a drop in the quasi-steady efficiency. However, these differences between quasi-steady in-phase and out-of-phase predictions were not replicated in the measured results, suggesting that the unequal admission loss is not as significant in pulsating flow as it is in steady flow.
Point prevalence and risk factors for work-related musculoskeletal disorders among academic staff in a Nigerian University

Work-Related Musculo-Skeletal Disorder (WRMSD) is a common complaint among the working population. In spite of the keen interest of Nigerian researchers in this subject, there is a dearth of information concerning university academic staff. Yet, this group of workers are critical to high-level manpower development. The aim of this study is to assess the risk factors and determine the point prevalence of WRMSD among academic staff of Nigeria premier University Ibadan. Two hundred and two (202) academic staff from all faculties in the university participated in this cross-sectional study. The methodology involved a two-part process namely: An observational assessment of each academic staff by one of the researchers; and completion of a self-administered questionnaire. The Standard Nordic Questionnaire and the Rapid Office Strain Assessment (ROSA) were used to assess musculoskeletal disorders and the ergonomic environment, respectively. Descriptive statistics of frequency percentage, mean and standard deviation were used to summarise the data. Inferential statistics of chi-square was also used at p<0.05. Participants were aged 49.3± 11.21 years. Results showed a WRMSDs prevalence of 86.6 and 64% reported that the musculoskeletal disorders or pain interfered with their work. The risk factors identified were inappropriate chairs and desk height; reaching for items in the workplace; prolonged sitting time and poor ergonomic awareness. The most common reported WRMSDs were those of upper back (78.7%); hip/buttocks (78.2%); knees (70.3%); and low back (41.6%). Based on the assessment of academic staff’s office work environment, 66.3% of them were adjudged to be at a high risk of developing WRMSDs. The importance of appropriate office furniture and an improved work environment for academic staff were highlighted.
Extreme Ultraviolet Explorer Photometry of RS Canum Venaticorum Systems: Four Flaring Megaseconds

We present an analysis of 12.2 Ms of Extreme Ultraviolet Explorer (EUVE) photometry of 16 RS CVn systems (including four flaring megaseconds). Our study attempts a systematic categorization of stellar coronal emission in RS CVn binary systems. The temporal resolution of the EUVE satellite and the opportunity for long observations enables us to study separately the quiescent and flaring states of RS CVn systems. Thirty of 31 observations are statistically variable. We examine light curves, characterizing both phase-dependent variations and large- and small-scale flaring. There is evidence for small-scale stochastic variability on the one short-period (Porb<1 day) system in our sample (ER Vul), which we interpret as small-scale flaring. CF Tuc is the only system for which phase-dependent variations over multiple orbital periods are seen. We analyze 30 flares on nine systems, fitting rise and decay times. Several flares have durations >0.5Porb and thus cannot originate from compact emission regions close to the stellar surfaces. Many flares have unusual flare morphologies, with rise times comparable to or greater than the decay time, and emission plateaus. In addition, eight flares have decay phases that are fit better by a broken power law than a single power law. The decay times for the second power law are statistically different than the single decay times and are correlated with the flare rise times. This observed connection points to the potential importance of the change in decay rate as a means of examining the physical processes operating during the flare. The distribution of orbital phases of flare onsets on V711 Tau (HR 1099), the best-studied RS CVn in our sample, is consistent with a Poisson distribution that is random in time. In two systems that are partially eclipsing (CF Tuc and ER Vul), we find no evidence for an eclipse in the light curve, indicating that the emission region is large compared to the stellar radius. We parameterize the distribution of flare energies as a power law, finding a cut-off energy of ≈1033 ergs and a slope of -0.6. Flare energy increases with flare duration as E∝Δt1. 42, confirming the long-duration nature of high-energy flares on RS CVn systems. The integrated flare luminosity depends on the quiescent luminosity as Lflare∝L1.05quiescent. Flare frequencies range from 0.1 day-1 to 1.5 day-1. For observations not affected by the dead spot on the Deep Survey detector, 40% of the observed time was spent in a flaring state, indicating that flaring is a "normal" state for the coronae of these systems. We note the presence of a quasi-periodicity in EUVE photometric data on the order of 1 day, which is not corrected for in the standard reduction and analysis software.
Radiative forces and abundance anomalies of manganese in peculiar stars

The Hg-Mn stars apparently have no magnetic field but overabundances of many elements, among them manganese. Manganese ions are pushed from the envelope to the atmosphere and, in the absence of a magnetic field, will continue to the interstellar matter unless the radiative acceleration on them decreases sufficiently at small optical depths. Radiative accelerations are then needed throughout the atmosphere and upper atmosphere.
Effects of 50 Hz electromagnetic fields on mitochondrial DNA copy number of mesenchymal stem cells with different states

Mitochondria play pivotal roles in a range of cellular functions. When mitochondria underwent significant changes during cellular differentiation, mitochondria DNA (mtDNA) copy number was elevated. Many reports showed that ElectroMagnetic Fields (EMF) could affect Mesenchymal Stem Cells (MSCs) differentiation. However, the effects of EMF on mitochondria DNA (mtDNA) copy number of MSCs have not been discovered. In this study, rat MSCs were isolated from bone marrow and divided to culture with three kinds of conditioned media, then exposed to EMF. EMF groups were exposed to 50 Hz EMF at 5 mT of flux densities for 30 min, 1 h or 6 h for 2 days. Control cultures were performed without EMF stimulation. The effects of EMF on mtDNA copy number were investigated. The results revealed that a transitory decrease in mtDNA content was observed during early osteoblastic differentiation of MSCs, but a sharp increase after neuronal induction for 3 days. After EMF exposure for 2 days, we found that 50 Hz EMF increased mtDNA copy number of MSCs in the pluripotent state and in a time-dependent manner during osteoblastic differentiation. During neuronal differentiation, mtDNA replication was enhanced after EMF exposure for 30 min, and then a gradual decrease in mtDNA content was observed after EMF exposure for 1 h and 6 h, respectively. Those results indicated that 50 Hz EMF had different effects on mtDNA copy number of MSCs with different states.
Moving Contact Lines: Scales, Regimes, and Dynamical Transitions

The speed at which a liquid can move over a solid surface is strongly limited when a three-phase contact line is present, separating wet from dry regions. When enforcing large contact line speeds, this leads to the entrainment of drops, films, or air bubbles. In this review, we discuss experimental and theoretical progress revealing the physical mechanisms behind these dynamical wetting transitions. In this context, we discuss microscopic processes that have been proposed to resolve the moving–contact line paradox and identify the different dynamical regimes of contact line motion.
Estimating Rainfall in the Tropics Using the Fractional Time Raining.

Abstract The relationship between the fractional time raining and tropical rainfall amount is investigated using raingage data and a point process model of tropical rainfall. Both the strength and the nature of the relationship are dependent upon the resolution of the data used to estimate the fractional time raining. It is found that highly accurate estimates of rainfall amounts over periods of one month or greater can be obtained from the fractional time raining so long as high-time-resolution data are used. It is demonstrated that the relationship between the fractional time raining and monthly atoll rainfall is quasi-homogeneous within the monsoon trough region of the equatorial western Pacific.
AKARI/AcuA PHYSICAL STUDIES OF THE CYBELE ASTEROID FAMILY

We present a study of 107 Cybele asteroids based on the archival database “Asteroid Catalog Using AKARI (AcuA)” taken by the Infrared Astronomical Satellite. The database provides diameters D > 10 km, geometric albedos, and taxonomic information (75%) of the Cybeles. We find taxonomic diversity (mainly C-, D-, and P-type) in the population of 78 small Cybeles with diameters 10 km <D < 80 km. Their cumulative power-law size distribution index shows a shallow value of 0.86 ± 0.03. By contrast, 29 large Cybeles with D > 80 km are mostly classified as C- or P-types (90%), with a power-law index of 2.39 ± 0.18. The total mass of Cybele asteroids is estimated to be ∼10−5 MEarth. We also discuss the origin and formation process of the Cybele asteroid family.
Typhoon-Position-Oriented Sensitivity Analysis. Part I: Theory and Verification

AbstractA new sensitivity analysis method is proposed for the ensemble prediction system in which a tropical cyclone (TC) position is taken as a metric. Sensitivity is defined as a slope of linear regression (or its approximation) between state variable and a scalar representing the TC position based on ensemble simulation. The experiment results illustrate important regions for ensemble TC track forecast. The typhoon-position-oriented sensitivity analysis (TyPOS) is applied to Typhoon Shanshan (2006) for the verification time of up to 48 h. The sensitivity field of the TC central latitude with respect to the vorticity field obtained from large-scale random initial perturbation is characterized by a horizontally tilted pattern centered at the initial TC position. These sensitivity signals are generally maximized in the middle troposphere and are far more significant than those with respect to the divergence field. The results are consistent with the sensitivity signals obtained from existing methods. The .
Velocity profiles of galaxies with claimed black holes — I. Observations of M31, M32, NGC 3115 and NGC 4594

The presence of a massive black hole has been invoked to match the observed rotation velocities and velocity dispersions at the centres of M31, M32, NGC 3115 and NGC 4594. Here we determine stellar line-of-sight velocity profiles of these galaxies, from high spatial resolution, high S/N spectra centred on the G-band, the Mg b triplet and the Ca II IR triplet. For all spectra we determine rotation velocities, V, velocity dispersions, sigma, and deviations of the velocity profiles from a Gaussian shape, as quantified by the Gauss-Hermite moments h3,. ,h6. Significant deviations of the velocity profiles from a Gaussian are present in all objects. The strongest deviations are asymmetries quantified by h3 and are found primarily along the major axis. The amplitude of h3 is typically \h3\ less than or similar to 0.15 and is correlated with V/sigma. Its sign always indicates an excess of stars at low rotation velocities, and results in the mean stellar streaming velocity being lower than the mean of the best-fitting Gaussian, the quantity conventionally used to characterize rotation. The difference is approximately 10 per cent for M31, M32 and NGC 3115, and approximately 20 per cent for NGC 4594. It is thus important that models take the observed velocity profile shapes into account. We demonstrate that the observed deviations from Gaussian velocity profiles are for the most part not the result of projection and seeing convolution. We calculate the velocity profiles predicted by Tonry's model for M32, taking seeing and projection into account, but assuming the local (unprojected) velocity distributions to be Gaussian. The predicted velocity profiles are nearly Gaussian, in conflict with our data. Self-consistent dynamical models must thus be constructed to fit the observed velocity profiles. Such models should constrain the central structure quite strongly, and will hence provide improved constraints on the mass and presence of a supermassive central object.
An integral equation for immiscible fluid isplacement in a two-dimensional porous medium or Hele-Shaw cell

Abstract An integral equation for the normal velocity of the interface between two immiscible fluids flowing in a two-dimensional porous medium or Hele-Shaw cell (one fluid displaces the other) is derived in terms of the physical parameters (including interfacial tension), a Green's function and the given interface. When the displacement is unstable, ‘fingering’ of the interface occurs. The Saffman-Taylor interface solutions for the steady advance of a single parallel-sided finger in the absence of interfacial tension are seen to satisfy the integral equation, and the error incurred in that equation by the corresponding Pitts approximating profile, when interfacial tension is included, is shown. In addition, the numerical solution of the integral equation is illustrated for a sinusoidal and a semicircular interface and, in each case, the amplitude behaviour inferred from the velocity distribution is consistent with conclusions based on the stability of an initially flat interface.