Miracle-dz/UniFAR-FTUs huggingface dataset:
Single‐electron effects in a point contact using side‐gating in delta‐doped layers

Side‐gated point‐contact structures in delta (δ)‐doped layers have been used to form single‐electron tunnel junctions with variable resistance. Clear Coulomb‐blockade effects have been observed in the current‐voltage characteristics. The measured characteristics are described in terms of a series of single‐electron transistors formed by microsegments within the point contact. The effective tunnel capacitance and side‐gate capacitance are estimated to be 10 and 1 aF, respectively, which are both one order of magnitude smaller than the reported capacitance of tunnel junctions made from Al or GaAs/AlGaAs heterostructures.
X-ray spectroscopy of five BL Lacertae objects

Five X-ray bright BL Lacertae objects were observed in the energy range 0.6-4.5 keV with the solid state spectrometer (SSS) of the Einstein Observatory. The 14 SSS spectra obtained represent most of the X-ray spectra of BL Lac objects with resolution better than approximately 3. These data do not reveal the presence of large amounts of thermal gas, with upper limits for the equivalent width of individual spectral features typically less that about 100 eV. However, the SSS spectra are the first set of X-ray data to indicate low-energy absorption in excess of that caused by the cold interstellar matter in the Galaxy. Comparison with contemporaneous, lower energy X-ray data implies that this absorption does not arise in cold neutral material, but in hotter, highly ionized material, probably intrinsic to the source. All five BL Lac objects have X-ray continua that are well fitted by power-law models, with power-law energy indices usually greater than about 1. In a few cases, a flattening at higher energies is observed; these and other data suggest that two-component X-ray spectra, steep at low energies and flat at high energies, are a common feature of BL Lac objects. Three of the five sources clearly varymore » between SSS observations, with time scales ranging from days to years. A historical synopsis of the X-ray spectral data confirms the tendency for BL Lacertae objects to be highly variable in the X-ray band but reveals no correlation between spectral and intensity changes. 5 references. « less
Impact of nonlinear propagation on temperature distributions caused by diagnostic ultrasound

As interest in imaging of the harmonics generated by nonlinear propagation in tissue has grown, it has been recognized that the patterns of heat deposition in tissue may be altered with respect to those observed with the assumption of linear propagation. Changes in the patterns of heat deposition have been studied by the use of computer simulations. The generation of harmonic energy has been simulated by a solution of Burger's equation by methods developed by Christopher and Parker. The bio-heat transfer equation has been solved by the method of finite differences. With these models, temperature differences that arise from assumed linear and nonlinear propagation have been made and the degree of greater potential of bioeffects have been made. Typically, nonlinear propagation moves the location of highest temperature increases closer to the transducer in soft tissue or to the bone surface in the fetal bone case. In some cases such as those where the acoustic beam travels through amniotic fluid, substantial increases (in the order of 50%) in temperature rise may occur. The impact of nonlinear propagation on regulatory models is discussed.
Applications of the wave kinetic approach: from laser wakefields to drift wave turbulence

Nonlinear wave-driven processes in plasmas are normally described by either a monochromatic pump wave that couples to other monochromatic waves, or as a random phase wave coupling to other random phase waves. An alternative approach involves a random or broadband pump coupling to monochromatic and/or coherent structures in the plasma. This approach can be implemented through the wave-kinetic model. In this model, the incoming pump wave is described by either a bunch (for coherent waves) or a sea (for random phase waves) of quasi-particles. This approach has been applied to both photon acceleration in laser wakefields and drift wave turbulence in magnetized plasma edge configurations. Numerical simulations have been compared to experiments, varying from photon acceleration to drift mode-zonal flow turbulence, and good qualitative correspondences have been found in all cases.
A Stellar Probe of Dark Matter Annihilation in Galactic Nuclei

Etude de l'evolution d'etoiles de la sequence principale placees dans un nuage tres concentre de matiere sombre (densite de l'ordre de ≥10 6 fois celle du halo pres du soleil). Dans le diagramme HR, les etoiles de faible masse sont decalees vers le rouge. La forte densite constatee devrait etre presente dans les noyaux de galaxies. Description d'un scenario d'evolution d'un noyau galactique contenant des etoiles et de la matiere sombre froide. Effet des effets de la friction dynamique sur les orbites de ces etoiles due a la matiere sombre froide
Use of the electro-mechanical impedance method for the assessment of dental implant stability

The robustness and reliability of the Electro-Mechanical Impedance (EMI) method to assess dental prostheses stability is presented. The study aim at addressing an increasing need in the biomedical area where robust, reliable, and non-invasive methods to assess the bone-interface of dental and orthopedic implants are increasingly demanded for clinical diagnosis and direct prognosis. In this study two different dental screws were entrenched in polyurethane foams and immersed in a solution of nitric acid to allow material degradation, inversely simulating a bone-healing process. This process was monitored by bonding a Piezoceramic Transducer (PZT) to the implant and measuring the admittance of the PZT over time. To simulate healing, a second set of experiments was conducted. It consisted of placing four dental screws inside a joint compound specimen and observing the setting of the fresh compound allocated in the alveolus containing each implant. In all cases it was found that the PZT's conductance and the statistical features associated with the analysis of the admittance signatures were sensitive to the degradation or the setting process.
Strong Ferromagnetism of 3d-Metal Overlayers on Pd(001)

We present full-potential linearized augmented-plane-wave calculations for 3d-metal overlayers (V, Cr, Mn, Fe, Co and Ni) on the Pd(001) surface. We find very large moments for the overlayers. In the series Ni, Co, Fe and Mn the overlayer moment roughly increases in steps of 1μB from a value of about 1μB for Ni to 4μB for Mn overlayers. We discuss this as a saturation effect which is due to the occurrence of strong ferromagnetism, i.e. a filled majority band of the overlayer. We also calculate the induced polarization in the first two layers of the Pd substrate.
Molecular tori in Seyfert galaxies - Feeding the monster and hiding it

The principal properties of the tori of gas which surround Seyfert nuclei are discussed. The internal state of the clouds and their size distribution function are examined, and it is shown that the Jeans mass scale results in clouds which are individually sufficiently opaque to block out the nucleus, and that the balance of processes which controls their size distribution function also forces the covering factor to be of the order of or greater than unity. Where the gravitational potential is dominated by stars, cloud-cloud collisions keep the molecular clouds close to the equatorial plane. Stirring by stellar processes is never strong enough to compete with collisional losses. The position of the inner edge of the torus is determined by a balance between the inward flow of clouds and the rate at which the nuclear continuum can evaporate them. 43 references.
The Partisan Paradox

The paper provides an explanation for why oﬃceholders persistently pursue partisan policies even though voters express preferences for non-partisan behaviour, and evidence suggests to of-ﬁceholders that voters would beneﬁt from non-partisan policies. We develop a dynamic model where oﬃceholders have private information about the beneﬁts of the policies they can implement. The policy issue itself is non-partisan—everyone has the same policy preferences—but candidates diﬀer in their expertise at implementing diﬀerent policies. To secure re-election by convincing voters that future circumstances favour their expertise, incumbents have an incentive to implement their partisan policy, even when they know it to be wrong. Importantly, incumbents pursue non-partisan policies only when circumstances suggest that pursuing partisan policies are particularly damaging. Thus, oﬃceholders pursue non-partisan policies precisely when it matters most to voters. Paradoxically, though, by doing so an oﬃceholder reveals the value of a rival’s expertise, ensuring his subsequent electoral defeat.
Absolute magnetometry at nanometer transverse spatial resolution: Holography of thin cobalt films in a scanning transmission electron microscope

A method for the absolute measurement of magnetization at nanometer spatial resolution in magnetic thin films has been developed. A biprism placed in the illumination system of a scanning transmission electron microscope allows the operation of two distinct holography modes. The absolute mode displays a linear change in phase difference for regions of constant magnetization and thickness and the slope determines the magnitude of magnetization. The differential mode displays a constant value of phase difference in these regions allowing a simple and straightforward determination of domain wall profiles. Micromagnetic structure extracted from identical areas of thin Co films is compared using the new holography modes, differential phase constrast Lorentz microscopy and conventional Fresnel Lorentz microscopy in the same instrument.
Constraints on the shape of the density spectrum from COBE and galaxy surveys

Many popular models for galaxy formation are based on power spectra which behave as P(k) = Ak for small k and flatten at large k. The resulting mass fluctuation can be constrained by galaxy surveys up to R about 60/h Mpc. Recent COBE results, however, constrain the dark matter spectrum at very large scales and are consistent with a scale-invariant density spectrum σ DM(R) . The extrapolated COBE results matches galaxy survey results at 50/h Mpc, suggesting that biasing is not significant at R greater than about 50/h Mpc. On the other hand, a CDM spectrum normalized to the COBE value overshoots galaxy survey results at small scales. Comparing the shape of sigma(R) at R less than about 60/h Mpc with the COBE results, it is found that relatively rapid bend in σ(R) around R 40-60/h Mpc is needed. It is shown that simple models describing this bend are severely constrained.
Thermal Impact of Saharan Dust over Land. Part I: Simnulation

Abstract Simulations are carded out to verify a mesoscale model in order to perform sensitivity tests of satellite response to atmospheric dust content. The model chosen is the mesoscale model of Colorado State University with a modified radiation parameterization in order to take atmospheric dust content into account. Downward and upward longwave irradiances are estimated using a 25-interval model. The shortwave pan of the spectrum is processed by a very fast, highly parameterized, single-interval code. Tests using experimental data gathered during the Etude de la Couche Limite Atmospherique Tropicale Seche (ECLATS) experiment performed during the 1980 dry season near Niamey (Niger, West Africa) prove that dust content is satisfactorily handled. Three 24-h simulations performed under various meteorological and turbidity conditions show that ground surface energy exchanges are satisfactorily described, so that surface temperature is predicted with a standard deviation of about 1°C. Vertical profiles of co.
The Chebotarov theorem for Galois coverings of Axiom A flows

Abstract We consider G (Galois) coverings of Axiom A flows (restricted to basic sets) and prove an analogue of Chebotarev's theorem. The theorem provides an asymptotic formula for the number of closed orbits whose Frobenius class is a given conjugacy class in G. An application answers a question raised by J. Plante. The basic method is then extended to compact group extensions and applied to frame bundle flows defined on manifolds of variable negative curvature.
Stochastic Orders Generated by Integrals: a Unified Study

We consider stochastic orders of the following type. Let be a class of functions and let P and Q be probability measures. Then define , if ∫ ⨍ d P ≦ ∫ ⨍ d Q for all f in . Marshall (1991) posed the problem of characterizing the maximal cone of functions generating such an ordering. We solve this problem by using methods from functional analysis. Another purpose of this paper is to derive properties of such integral stochastic orders from conditions satisfied by the generating class of functions. The results are illustrated by several examples. Moreover, we show that the likelihood ratio order is closed with respect to weak convergence, though it is not generated by integrals.
Modeling high power light-emitting diode spectra and their variation with junction temperature

Spectral radiant flux is the primary optical characteristic of a light source, determining the luminous flux and color. Much research is dedicated to the modeling of light-emitting diode (LED) spectra and their temperature dependence, allowing for the simulation of optical properties in various applications. Most of the spectral radiant flux models that have been published so far are purely mathematical. For this paper, spectral radiant fluxes of commercial single color LED packages have been measured in a custom made integrating sphere at several junction temperatures by active cooling and heating with a Peltier element. A spectrum model at 300 K is constructed where the Boltzmann free carrier distribution and carrier temperature are included. Subsequently, the model is extended with the carrier temperature variation, the band gap energy shift, and the nonradiative recombination rate decrease with junction temperature. As a result, the skewness variation, peak frequency shift, and peak value change in the spectrum with temperature can be predicted. The model has been validated by comparing flux and color coordinates of measured and simulated spectra at 340 K junction temperature. In practice, only two spectral flux measurements at different junction temperatures are needed to accurately simulate a single color spectrum at any temperature.Spectral radiant flux is the primary optical characteristic of a light source, determining the luminous flux and color. Much research is dedicated to the modeling of light-emitting diode (LED) spectra and their temperature dependence, allowing for the simulation of optical properties in various applications. Most of the spectral radiant flux models that have been published so far are purely mathematical. For this paper, spectral radiant fluxes of commercial single color LED packages have been measured in a custom made integrating sphere at several junction temperatures by active cooling and heating with a Peltier element. A spectrum model at 300 K is constructed where the Boltzmann free carrier distribution and carrier temperature are included. Subsequently, the model is extended with the carrier temperature variation, the band gap energy shift, and the nonradiative recombination rate decrease with junction temperature. As a result, the skewness variation, peak frequency shift, and peak value change in th.
Exploratory graphics for financial time series volatility

The paper develops a framework for volatility graphics in financial time series analysis which allows exploration of the time progression of volatility and the dependence of volatility on past behaviour. It is particularly suitable for identifying volatility structure to be incorporated in specific volatility models. Plotting techniques are identified on the basis of a general time series volatility model and are illustrated on the Financial Times Stock Exchange 100‐Share Index financial time series. They are statistically validated by bootstrapping and application to simulated volatile and non‐volatile series, generated by both conditionally heteroscedastic and stochastic volatility models. An important point is that volatility can only be properly visualized and analysed for linearly uncorrelated or decorrelated series.
A bayesian model for the analysis of lactation curves of dairy goats

This article aims to determine the effect of certain covariates, such as season of kidding, parity, and time of kidding on the characteristics of the lactation curve of Saanen dairy goats. Characteristics investigated are peak milk yield, time of peak milk yield, total milk production, persistency, and the relationship between fat and protein in milk composition, as well as between lactation curves of the same animal in successive years. The analysis is carried out using a hierarchical Bayesian approach, together with Wood’s model, to model lactation. Posterior distributions of quantities of interest are obtained by means of the Markov chain Monte Carlo (MCMC) methods. These clearly illustrate the significant effect of especially parity, but also season and time of kidding on the characteristics of the lactation curve. Total and peak milk yield increase with increasing parity up to about the third or fourth parity, while peak yield is later for first than for later parities. The analysis also enables estimation of lactation characteristics of untested animals, prediction of future characteristics and identification of exceptional animals.
Properties of La-silicate high-K dielectric films formed by oxidation of La on silicon

In this article, we present data on the properties of La-based high-k dielectric films prepared by oxidation of La deposited by physical vapor deposition on silicon. Films are characterized by x-ray photoelectron spectroscopy, infrared absorption, and capacitance versus voltage analysis. We find that when we oxidize La metal sputter deposited on Si substrates, it reacts with the silicon substrate to form La silicate. La films as thick as 300 A will react completely with Si under moderate oxidation conditions (900 °C for 10 min) suggesting a very rapid silicidation reaction between La and Si. Under some processing conditions the as-deposited films contain a small La2O3 component that reduces to La silicate upon anneal at high temperatures. La-silicate films do not phase separate into La2O3 and SiO2 upon annealing at 1050 °C, and their resistance to H2O incorporation depends critically on the oxidation temperature. Electrical measurements show a high concentration of positive fixed charge.
Ensemble prediction using dynamically conditioned perturbations

We apply the technique developed in the companion paper by Molteni and Palmer (1993) as a means of providing dynamically conditioned perturbations for ensemble forecasting with a primitive-equation model. Four wintertime initial states are chosen—three at random and one because of substantial development in the large-scale flow within four days, which the control forecast completely missed. A set of singular vectors are created using a quasi-geostrophic model linearized about basic states taken from data close to the chosen initial dates. These are interpolated onto the primitive-equation-model grid, and used as perturbations to the initial state. An ensemble forecast is made form the perturbed initial states. The dispersion of this ensemble is compared, for each date, with that from a second ensemble with initial perturbations constructed from 6-hour-forecast errors. Throughout the forecast period, it is found that the amplitude of the perturbations is noticeably larger using the singular vectors. The dispersion of the ensembles using the forecast-error perturbations did not indicate that the control forecast form the case with substantial development was likely to be poor. By contrast, the (envelope) dispersion of the ensemble using the singular vectors was notably larger for this case than the other three. A number of members of this ensemble were particularly skilful in predicting weather-related elements of the flow, such as low-level temperature change. It is found that the evolution of perturbations which are initially localized over the western Pacific, or western Atlantic, can develop blocking-like structures several days later over the eastern oceans. With the initial amplitudes used in this paper, the development of these structures is in part nonlinear. The growth of the singular-vector perturbations was not as large in the primitive-model as in the quasi-geostrophic model, probably due to interpolation problems exacerbated by inconsistent orographic representation. Further work to overcome these, and other, problems is indicated.
New Methods for the Analysis of Change

Methods for measuring and modeling change have been a topic of intense research concern and consternation for the past four decades, if not longer. The classic book Problems in Measuring Change, edited by Chester Harris and published in 1963, cast a pall on the field, and Cronbach and Furby (1970) challenged further the status of change scores. If developmental change is construed as a difference score or change score, the preceding works led many to conclude that experts in statistical methodology had demonstrated that developmental change is too unreliable to be the object of scientific study. But such a summary judgment—reached largely by manipulating equations, not data—seemed to fly in the face of experience by practicing scientists that some children appear to grow at faster rates than others, that aging adults exhibit remarkable variability in their rates of decline. If developmental change is so unreliable, how could developmental change be so apparent, replicable, and tangible? Happily, an avalanche of contributions has been made on the topic of modeling change during the past decade or two. The upshot of these more recent contributions is that, even if the methods for doing so are, or seem, a bit arcane, developmental change should be the object of study and can be modeled reliably. One important contribution that promoted the modeling of change was a volume titled Best Methods for the Analysis of Change: Recent Advances, Unanswered Questions, Future Directions, published in 1991 and edited by Linda Collins and John Horn. The current volume is a valuable follow-up to that effort, surveying advances in methods for analyzing change after a decade of additional work. In the preface to the current volume, Linda Collins and Aline Sayer note that at least one reviewer complained about the title of the 1991 Collins and Horn book, calling a book with a title of “best methods” offensive, presumably because the title implied that methods considered therein had special valued status over methods inadvertently excluded. This observation leads the discerning reader to consider carefully the title of the current volume, New Methods for the Analysis of Change. Are all methods in the book really new? If all methods are indeed new, are they truly notable advances over previously proposed approaches or techniques? Even if one opined that the current volume contains much that is new and valuable, one is tempted to mimic the Baron Brougham and Vaux and observe that, alas, “what is valuable is not new, and what is new is not valuable. ” The baron’s wry observation implies a strong inverse relation between novelty and value, and this would be a quite inapt characterization of contributions in the Collins and Sayer book. On the other hand, although the magnitude and valence of the relation between novelty and value is