Miracle-dz/UniFAR-FTUs huggingface dataset:
Asymptotics for generalized estimating equations with large cluster sizes

Generalized estimating equations are used in regression analysis of longitudinal data, where observations on each subject are correlated. Statistical analysis using such methods is based on the asymptotic properties of regression parameter estimators. This paper presents asymptotic results when either the number of independent subjects or the cluster sizes (the number of observations on each subject) or both go to infinity. A set of (information matrix based) general conditions is developed, which leads to the weak and strong consistency as well as the asymptotic normality of the estimators. Most of the results are parallel to the elegant work of Fahrmeir and Kaufmann on maximum likelihood estimators related to the generalized linear models. The conditions for weak consistency and asymptotic normality are verified for several examples of general interest.
Diagnosing mixing in stratified turbulent flows with a locally defined available potential energy

Abstract A local available potential energy (APE) density useful as suitable diagnostic tool in turbulent stratified flows is considered under the Boussinesq approximation. The local APE is positive, and in the limit of infinitesimal perturbation from an equilibrium state recovers the Lorenz energy cycle definition of APE. In a turbulent stratified flow, the APE can be Reynolds-decomposed into non-trivial mean and turbulent components, which are connected to the mean and turbulent kinetic energy by suitably defined fluxes. We show that the turbulent buoyancy flux $\overline{w'b'}$ and the rate of production of turbulent APE coincide only under very special circumstances. The framework is applied to derive some global bounds on the mixing efficiency of some representative flows.
Equilibrium for radiation in a homogeneous plasma

Entropy increase and comparison principles are found for the Fokker–Planck equation for the radiation field in a homogeneous plasma with constant electron temperature. When emission– absorption is neglected, this is used to find equilibrium distributions that have the form of a Planck distribution plus a δ function at zero photon energy. For distributions below the Planck and with emission–absorption included, a rate of entropy increase is obtained. Numerical results confirm these conclusions.
Standing Rankine-Hugoniot Shocks in the Hybrid Model Flows of the Black Hole Accretion and Winds

This paper presents all the Rankine-Hugoniot shock solutions for the stationary, axially symmetric and rotating adiabatic flows of small transverse thickness in the black hole potential. The recently proposed hybrid model is used to treat the flows which include shocks. It is shown that, for given initial and final states of the flow, there can be as many as four formal shock locations in both the accretion and the winds. Only two (three) of these locations are acceptable for accretion onto black holes (neutron stars), and three of these locations are acceptable for winds. It is shown that the question of the multiplicity of the shocks cannot be resolved by local stability analysis of the shocks. In addition, the properties of the isentropic compression waves and the isothermal shocks are briefly studied. 17 refs.
X-ray emitting T Tauri stars in the L1551 cloud

Low mass pre-main sequence stars in the nearby Lynds 1551 star forming cloud are studied with the ROSAT and ASCA X-ray satellites. An 8 ksec ROSAT image reveals 38 sources including 7 well-known T Tauri stars, 2 likely new weak-lined T Tauri stars, 5 potential new weak-lined T Tauri stars, one is a young B9 star, and the remaining sources are unrelated to the cloud or poorly identified. A 40 ksec ASCA image of the cloud detects seven of the ROSAT sources. Spectral fitting of the brighter X-ray emitting stars suggests the emission is produced in either a multi-temperature plasma, with temperatures near 0.2 and 1 keV, or a single-temperature plasma with low metal abundances. XZ Tau, a young classical T Tauri star, is much stronger in ASCA than ROSAT observations showing a harder (1.5-2.0 kev) component. Timing analysis reveals all but one of the T Tauri stars are variable on timescales ranging from one hour to a year. A powerful flare, emitting 3 x 10(exp 34) ergs within a 40 minute rise and fall, was observed by ASCA on the weak-lined T Tauri star V826 Tau. The event was preceded and followed by constant quiescent X-ray emission. The extreme classical T Tauri star XZ Tau was also caught during both high and low states, varying by a factor of 15 between the ASCA and ROSAT observations. Neither of the luminous infrared embedded protostars L1551-IRS 5 or L1551NE were detected by ROSAT or ASCA.
Lifetime-degrading boron-oxygen centres in p-type and n-type compensated silicon

Degradation of minority carrier lifetime under illumination occurs in boron-containing Czochralski silicon of both p- and n-type. In n-Si, the recombination centre responsible for degradation is found to be identical to the fast-stage centre (FRC) known for p-Si, where it is produced at a rate proportional to the squared hole concentration, p2. Holes in n-Si are the excess minority carriers—of a relatively low concentration; hence, the time scale of FRC generation is increased by several orders of magnitude when compared to p-Si. The degradation kinetics, which is non-linear, due to dependence of p on the current concentration of FRC, is well reproduced by simulations. The injection level dependence of the lifetime shows that FRC exists in 3 charge states (− 1, 0, + 1) possessing 2 energy levels. Comparison of n-Si samples of various electron concentrations shows that FRC emerges by the reconstruction of a latent BsO2 complex of a substitutional boron and an oxygen dimer (while the major recombination cen.
Spectra of atmospheric scalars

In Part 1 a wide-band spectrum of atmospheric pressure extending from periods of 1 week to 0.2 second is shown. The various frequency ranges are discussed with particular attention given to the midfrequency range. It is shown that convective activity and internal gravity waves can greatly modify the normal spectral distribution at midfrequencies and a specific example is discussed in detail. The amplitude spectrum of waves on the inversion layer is computed for this example from the surface pressure perturbations. In Part 2 evidence is presented indicating that the spectra of passive scalars aloft show a systematic departure from the power law distribution to be expected for a fully developed inertial subrange. The band of wave numbers analyzed in this report corresponds to scale sizes of 3 to 1000 feet. The ‘energy’ at the larger scales (small wave numbers) is quite variable and depends on altitude and atmospheric stratification. At the small scales the ‘energy’ is remarkably constant, and a source of refractive index variance at scales of 10 to 100 feet is indicated. Very thin layers of exceptionally large mean-square fluctuation are found in regions of gradient of scalars.
THE EFFECTS OF LOCAL INTERSTELLAR MAGNETIC FIELD ON ENERGETIC NEUTRAL ATOM SKY MAPS

We study the effects of the strength and direction of the local interstellar magnetic field (ISMF) on the heliosphere geometry that generates the locus of points associated with the position of the IBEX ribbon of energetic neutral atoms. MHD heliosphere models are run for a variety of ISMF parameters to specifically study the correlation between locations of maxima of the ISMF magnitude along the field lines and places where the local ISMF B is perpendicular to radial vectors r from the Sun, i.e., B · r = 0. The study confirms the existence of a strong physical relationship between the ribbon and the ISMF.
Territory and population attributes affect Florida scrub‐jay fecundity in fire‐adapted ecosystems

Abstract Fecundity, the number of young produced by a breeding pair during a breeding season, is a primary component in evolutionary and ecological theory and applications. Fecundity can be influenced by many environmental factors and requires long‐term study due to the range of variation in ecosystem dynamics. Fecundity data often include a large proportion of zeros when many pairs fail to produce any young during a breeding season due to nest failure or when all young die independently after fledging. We conducted color banding and monthly censuses of Florida scrub‐jays (Aphelocoma coerulescens) across 31 years, 15 populations, and 761 territories along central Florida's Atlantic coast. We quantified how fecundity (juveniles/pair‐year) was influenced by habitat quality, presence/absence of nonbreeders, population density, breeder experience, and rainfall, with a zero‐inflated Bayesian hierarchical model including both a Bernoulli (e.g., brood success) and a Poisson (counts of young) submodel, and random effects for year, population, and territory. The results identified the importance of increasing “strong” quality habitat, which was a mid‐successional state related to fire frequency and extent, because strong territories, and the proportion of strong territories in the overall population, influenced fecundity of breeding pairs. Populations subject to supplementary feeding also had greater fecundity. Territory size, population density, breeder experience, and rainfall surprisingly had no or small effects. Different mechanisms appeared to cause annual variation in fecundity, as estimates of random effects were not correlated between the success and count submodels. The increased fecundity for pairs with nonbreeders, compared to pairs without, identified empirical research needed to understand how the proportion of low‐quality habitats influences population recovery and sustainability, because dispersal into low‐quality habitats can drain nonbreeders from strong territories and decrease overall fecundity. We also describe how long‐term study resulted in reversals in our understanding because of complications involving habitat quality, sociobiology, and population density.
Estimates of short‐range forecast‐temperature error correlations and the implications for radiance‐data assimilation

The importance of an accurate specification of short‐range forecast‐error structures for the successful assimilation of satellite sounding data is discussed, with special emphasis on the role of vertical (inter‐level) error correlations. Two different statistical approaches for estimating these correlations are examined. The first is based on comparing radiosonde profiles with the short‐range forecast. The second compares forecasts of different lengths which verify at the same time. It will be shown that, in some aspects, the two approaches produce consistent results which suggests that significant geographic and seasonal variability exists in the vertical error correlations. The effect of not modelling this variability in the analysis of TOVS (TIROS‐N (Television Infra‐Red Observation Satellite) Operational Vertical Sounder) radiance data is simulated using a linear retrieval estimator, and it is shown that it may result in a serious misinterpretation of the information in the observations.
Prediction of Unsteady Natural Convection within a Horizontal Narrow Annular Space Using the Control-Volume Method

ABSTRACT Oscillatory natural convection in a narrow horizontal space is investigated numerically using the control-volume method. A parametric study for Rayleigh number is carried out using the power-law scheme and a confrontation with the central-difference scheme is developed. At intermediate values of the Prandtl number, complex interaction between hydrodynamic and thermal instabilities exists. For Pr = 0.2, gradual transitions from monocellular to three-top cell regimes are registered, the phenomenon of coalescence and separation of like-rotating cells is observed, and a subharmonic instability, followed by an early chaotic flow, is depicted. A disagreement between the power-law and the central-difference schemes results exists; the latest ones are in good agreement with the finite-difference method computations. However, the central-difference scheme results suffer from the false diffusion phenomenon.
The chemical composition of H ii regions in the outer Galaxy

New spectroscopic observations, including the optical and near-infrared ranges, have been obtained for a sample of H II regions located towards the Galactic anticentre. The sample includes H II regions with known galactocentric distances, their ionizing stars having been clearly identified from previous work. The spectra correspond to low-to-intermediate excitation nebulae, ionized by one/few late 0/ early B star(s). The global parameters of the regions, as well as their physical parameters such as electron density and temperature, are presented. Abundances have been computed using direct (spectroscopic) determinations of the electron temperature for some of the objects or alternatively assuming an adopted electron temperature derived from photoionization model fitting. Overall, the data appear to show a substantially flat gradient for the nitrogen abundance, going up to 18 kpc of galactocentric distance, as well as a mild gradient, if any, for oxygen. The data points for sulphur, although less numerous, give abundances which are consistent with the behaviour observed for the other elements. The N/O ratio also presents a very flat gradient across the outer Galaxy, with a value similar to the one derived from observations of optical emission lines of H II regions in the solar neighbourhood.
Numerical Investigation of the Fundamental Mechanism for Entropy Noise Generation in Aero-Engines

Abstract In the present work, the generation and propagation of entropy noise is computed using a compressible URANS approach in combination with appropriate acoustic boundary conditions. The Entropy Wave Generator (EWG) experiment is best suited for validating the proposed approach and for investigating the acoustic sources of entropy noise. The EWG involves a non-reactive tube flow, where entropy modes are imposed to an incoming air flow by using a heating module. The generated temperature non-uniformities are accelerated with the mean flow downstream in a convergent divergent nozzle, thus producing entropy noise. Simulation results of pressure fluctuations and their spectra for a defined standard configuration as well as for diff erent operating points of the EWG agree very well with the respective experimental data. Additionally, an analysis of the acoustic sources was performed. For this purpose the acoustic sources caused by the acceleration of density inhomogeneities were calculated. For the first time, a numerical method is introduced for the localization of the acoustic sources of entropy noise in acceleration/deceleration regions.
Estimation of interaction potentials of gibbsian point processes

A general method for estimating parameters of parametrized local energies of Gibbsian pint processes is given. It can be used also in the case of marked point processes. The application of the method is demonstrated by an example, where pair and triplet potentials are estimated. Furthermore, the relation between a pair potential and the corresponding product density is considered.
Energy-dependent electron-energy-loss spectroscopy: Application to the surface and bulk electronic structure of MgO

The various effects that can occur when the primary electron energy, E/sub p/, is varied in a reflection-energy-loss experiment are considered. For E/sub p/> or =100 eV, the dominant effect is an increase of the electron mean free path with increasing E/sub p/. By performing energy-loss measurements with 100 eV< or =E/sub p/< or =2000 eV, it is possible to unambiguously separate bulk and surface features in loss spectra. That technique has been applied to the MgO (100) surface, and both Mg intraionic and O-to-Mg interionic transitions have been studied. The former transitions are found to agree well with the excited-state spectra of free Mg/sup 2 +/ ions, while the latter agree more closely with itinerant-electron calculations of MgO. Intrinsic surface-state transitions are seen in both Mg/sup 2 +/ and O-to-Mg spectra. The Mg core-level surface-state spectra can be explained by Stark splitting of the surface Mg/sup 2 +/ levels in the intense electric fields at the crystal surface. The surface-state structure seen in O-to-Mg loss spectra agrees with discrete variational X.cap alpha. calculations of the MgO (100) surface and disagrees with linear combination of atomic orbitals calculations of the same surface. A low-energy-loss peak, possibly associated with surface defects,more » is seen on some surfaces; the exact nature of the surface defects involved is not yet clear. « less
A cohomology for foliated manifolds

A modular opening switch for high currents providing high current-carrying capacity, high voltage hold-off capability and very short opening time. The switch operates on the principle of an explosively generated pressure which ruptures and then drives paraffin radially through a cylindrical current conducting tube, so that the paraffin provides an electrically insulative barrier between the ruptured portions of the conducting tube. Alternate cutting and bending rings, between which insulating rings are placed, are disposed around the periphery of the conductor tube. The insulating rings are tapered at the periphery of the conductor tube to provide void spaces into which the paraffin is driven and firmly packed without voids or cracks which deteriorate the insulating property of the paraffin.
Positive Integrals of Bessel Functions

It is shown that some new and some already known positivity results for integrals of Bessel functions and for generalized hypergeometric functions can be easily obtained by writing the integrals and functions either as a sum of squares of Bessel functions with positive coefficients or as a fractional integral of such a sum. In particular, this method is used to prove that $\int_0^x {(x - t)^\lambda t^{\lambda + {1 / 2}} J_\alpha (t)dt > 0,\quad 0 \leqq \lambda \leqq \alpha - {1 / 2},\quad \alpha > 1/2, \quad x > 0,} $ and to give a simple proof of Steinig’s recent result that the Lommel function $S_{\mu ,\nu } (x) > 0$ for $x > 0$ if, $\mu = {1 / 2}$ and $ - {1 / 2} {1 / 2}$ and $ - \mu \leqq \nu \leqq \mu $.
Dynamics of a Flexible-hub Geometrically Nonlinear Beam with a Tip Mass

The dynamics of a flexible-hub geometrically nonlinear beam carrying a tip mass is presented. The hub-beam system is assumed to move in plane and the hub is restrained by a translational and a rotational spring. Hamilton’s principle is used to derive the equations of motion and their boundary conditions. A flexural model that takes into account the geometrical coupling between the axial and lateral deformations and ignores the axial deformation and its time derivatives is obtained. An exact solution for the natural frequencies and mode shapes of the free vibration problem is obtained. Using these mode shapes, a reduced-order model of the system is obtained using the Galerkin’s method. The dynamic response of the system using the present low-order model shows excellent agreement with the recent finite-element solutions available in the literature.
Neuroprotective activity of a virus‐safe nanofiltered human platelet lysate depleted of extracellular vesicles in Parkinson's disease and traumatic brain injury models

Abstract Brain administration of human platelet lysates (HPL) is a potential emerging biotherapy of neurodegenerative and traumatic diseases of the central nervous system. HPLs being prepared from pooled platelet concentrates, thereby increasing viral risks, manufacturing processes should incorporate robust virus‐reduction treatments. We evaluated a 19 ± 2‐nm virus removal nanofiltration process using hydrophilic regenerated cellulose hollow fibers on the properties of a neuroprotective heat‐treated HPL (HPPL). Spiking experiments demonstrated >5.30 log removal of 20–22‐nm non‐enveloped minute virus of mice‐mock particles using an immuno‐quantitative polymerase chain reaction assay. The nanofiltered HPPL (NHPPL) contained a range of neurotrophic factors like HPPL. There was >2 log removal of extracellular vesicles (EVs), associated with decreased expression of pro‐thrombogenic phosphatidylserine and procoagulant activity. LC‐MS/MS proteomics showed that ca. 80% of HPPL proteins, including neurotrophins, cytokines, and antioxidants, were still found in NHPPL, whereas proteins associated with some infections and cancer‐associated pathways, pro‐coagulation and EVs, were removed. NHPPL maintained intact neuroprotective activity in Lund human mesencephalic dopaminergic neuron model of Parkinson's disease (PD), stimulated the differentiation of SH‐SY5Y neuronal cells and showed preserved anti‐inflammatory function upon intranasal administration in a mouse model of traumatic brain injury (TBI). Therefore, nanofiltration of HPL is feasible, lowers the viral, prothrombotic and procoagulant risks, and preserves the neuroprotective and anti‐inflammatory properties in neuronal pre‐clinical models of PD and TBI.
Magnetic domain patterns in Co2MnGe Heusler nanostripes

We have prepared thin films of the ferromagnetic Heusler alloy Co2MnGe on a-plane Al2O3 substrates exhibiting growth-induced, superimposed fourfold and uniaxial magnetic anisotropies, the symmetry being determined by the single-crystalline Al2O3 substrate. The magnitude of the uniaxial anisotropy compared to the cubic anisotropy can be tuned over a wide range by the film thickness and the growth conditions. On submicrometer-wide stripes of Co2MnGe prepared by electron beam lithography we studied magnetic domain patterns by magnetic force microscopy. For stripes with a sufficiently large uniaxial anisotropy and with the easy axis oriented perpendicular to the stripe axis, we find perfectly regular domain patterns with the magnetization direction perpendicular to the stripe axis and alternating from domain to domain. The highly regular and controllable domain patterns in Co2MnGe nanostripes could be useful for magnetic storage devices and applications related to spin transfer torque.
Chaos synchronization based on intermittent state observer

This paper describes the method of synchronizing slave to the master trajectory using an intermittent state observer by constructing a synchronizer which drives the response system globally tracing the driving system asymptotically. It has been shown from the theory of synchronization error-analysis that a satisfactory result of chaos synchronization is expected under an appropriate intermittent period and state observer. Compared with continuous control method, the proposed intermittent method can target the desired orbit more efficiently. The application of the method is demonstrated on the hyperchaotic Rössler systems. Numerical simulations show that the length of the synchronization interval τs is of crucial importance for our scheme and the method is robust with respect to parameter mismatch.
Generalizations of F. E. Browder's sharpened form of the schauder fixed point theorem

Abstract Let E be a Hausdorff topological vector space, let K be a nonempty compact convex subset of E and let f, g: K → 2E be upper semicontinuous such that for each x ∈ K, f(x) and g(x) are nonempty compact convex. Let Ω ⊂ 2E be convex and contain all sets of the form x − f(x), y − x + g(x) − f(x), for x, y ∈ K. Suppose p: K × Ω →, R satisfies: (i) for each (x, A) ∈ K × Ω and for ε > 0, there exist a neighborhood U of x in K and an open subset set G in E with A ⊂ G such that for all (y, B) ∈ K ×Ω with y ∈ U and B ⊂ G, | p(y, B) - p(x, A)| < ε, and (ii) for each fixed X ∈ K, p(x, ·) is a convex function on Ω. If p(x, x − f(x)) ≤ p(x, g(x) − f(x)) for all x ∈ K, and if, for each x ∈ K with f(x) ∩ g(x) = ø, there exists y ∈ K with p(x, y − x + g(x) − f(x)) < p(x, x − f(x)), then there exists an x0 ∈ K such that f(x0) ∩ g(x0) ≠ ø. Another coincidence theorem on a nonempty compact convex subset of a Hausdorff locally convex topological vector space is also given.