Miracle-dz/UniFAR-FTUs huggingface dataset:
A hybrid grid/particle filter for Lagrangian data assimilation. I: Formulating the passive scalar approximation

In this two‐part paper, we present a new nonlinear method for the assimilation of Lagrangian data. In part I, we formulate the method as a generalization of other particle filters. A particularly novel feature of the formulation is the use of a hybrid discretisation of the probability density function (PDF) in physical/phase space. Moreover, we show that, under the assumption that the drifters are uncorrelated, the projection of the Fokker–Planck equation onto the observation space associated with the drifter positions reduces to a set of passive scalar equations. This property allows us to efficiently compute the transitional PDF. To compute the analysis states, we present a grid/particle filter specifically formulated for use with the hybrid representation of our PDF. In common with other particle filters, our filter can suffer from sample impoverishment. To remedy this problem, we extend the Gaussian resampling procedure of Xiong et al. to produce a very efficient filter. This produces a fully functional scheme for Lagrangian data assimilation when combined with our forecasts of the prior. Copyright © 2008 Royal Meteorological Society
A superlens for the deep ultraviolet

A superlens based on a single aluminum layer operating at deep ultraviolet (UV) wavelengths is investigated both, theoretically and experimentally. Using a wavelength of 157 nm double slits with a center-to-center separation of only 70 nm were experimentally resolved and simulations indicate a possible resolution down to 29 nm with experimentally feasible arrangements. The results demonstrate the significance of aluminum as plasmonic material for the deep UV.
Observations of Molecular and Atomic Clouds in M31

The first coordinated CO and H I observations of M31 made with identical and sufficiently high angular and velocity resolutions to resolve individual GMCs have been obtained. Extensive observations of a star-forming complex located within a portion of a spiral arm about 7 kpc from the center of M31 are reported. The distribution of both atomic and molecular gas is clearly correlated in both space and velocity. The H I line widths are typically around 25 km/s and usually a factor of two broader than CO lines detected along the same lines of sight. The molecular clouds are associated with H II regions and appear to be active sites of star formation. Comparison of H I and CO observations suggest that molecular clouds form from atomic gas on relatively short time scales within a spiral arm. 52 references.
THE POSSIBILITY OF COMPENSATING ASTRONOMICAL SEEING

The severe limitations imposed upon nearly all astronomical observations by "seeing" the effects resulting from passage of light rays through the turbulent atmosphere of the earth are familiar to every observer. With a small instrument the effect may appear largely as a continual shifting and scintillation of the image of a star, but with a large telescope poor seeing usually manifests itself mainly as an enlargement and blurring of the image. The reason for this difference becomes apparent when one makes a knife-edge test with a large telescope on a bright star. The turbulent elements of the atmosphere appear as shifting dark and bright areas on the image of the objective. In general these turbulent elements or waves have dimensions of the order of a foot or two small compared to the aperture of a large reflector. Thus the integrated effect of a number of turbulent elements leads to an unsteady enlargement of the image, perhaps with some irregular shifting in position. The seriousness of this is evident when one realizes that ideally the 200-inch Hale telescope is capable of giving diffraction images of stars about %0 oi a second of arc in diameter, yet the size of the "seeing image" produced is in the range j4 second to perhaps 5 or 10 seconds, being about 2 seconds in diameter on the average. Only rarely are images as small as yi second observed, and one may consider himself fortunate to experience one hour out of 1000 of the finest seeing, even at the best locations.
Whistler-induced amplitude perturbation in VLF propagation

Sudden changes in the amplitude of long-distance subionospheric VLF transmissions were found at night in association with whistlers. Both increases and decreases in signal strength were observed, depending on signal frequency and orieniation of the receiving antenna. Sample observations at Eights Station in Antarctica of station NSS (Annapolis, Maryland) on 22.3 kHz showed increases in signal strength that averaged 3 db, with rise times of about 2 sec and durations of about 30 sec. Coincident with every rise was a midlatitude (L approximately 2.5) whistler originating in the northern hemisphere. To explain this association, it is suggested that the whistler dumps energetic (30-300 keV) electrons into the D region. The resulting ionization then alters the properties of the earthionosphere wave guide. The mechanism of precipitation is thought to be pitch angle scattering of trapped electrons that resonate with the magnetic field of the whistler wave near the magnetic equator. (auth)
Some Bounds for Discounted Sequential Decision Processes

New bounds are obtained on the optimal return function for what are called discounted sequential decision processes. Such processes are equivalent to ones satisfying the contraction and monotonicity properties (Denardo [Denardo, E. V., 1967. Contraction mappings in the theory underlying dynamic programming. SIAM Review. Vol. 9, pp. 165-177.]). The bounds are useful primarily in the infinite horizon case. Certain subprocesses are exploited, based on the simple notion of taking only those states which are relevant into consideration. Some existing algorithms and some of their obvious extensions are listed. The possibility of identifying nonoptimal decisions, as in MacQueen [MacQueen, J. B. , 1966. A Modified dynamic programming method for markovian decision problems. Journal of Mathematical Analysis and Applications. Vol. 14, pp. 38-43. ], is included.
An acoustic study of palatalization of fricatives in American English

The alveolar fricative consonants (/s,z/) are sometimes palatalized when they appear adjacent to a palatal consonant (/s,ž,y/) as, for instance, in “this ship” or “us yet. ” Two questions about this process were studied for six speakers recorded during both spontaneous conversation and sentence reading: (1) When do these palatalizable sequences merge toward a single phonetic unit? and (2) How similar are the resulting merged sounds to the corresponding English palatal segments (/s,ž/)? Both duration and spectral measurements were made. Preliminary results indicate that an alveolar fricative palatalizes more frequently and more completely when it is followed by a palatal fricative than when it is preceded by one. In addition, some palatalizable sequences merge toward the form of a palatal segment, but others merge into acoustic forms which do not correspond to any English segment. Detailed analyses of temporal and spectral characteristics can be used to evaluate alternative accounts of palatalization in ter.
Strong lensing in RX J1347.5−1145 revisited

We present a revised strong lensing mass reconstruction of the galaxy cluster RX J1347.5-1145. The X-ray luminous cluster at redshift z=0.451 has already been studied intensively in the past. Based on information of two such previous (strong-)lensing studies by Halkola et al. (2008) and Bradac et al. (2008), as well as by incorporating newly available data from the Cluster Lensing And Supernovae survey with Hubble (CLASH, Postman et al. 2012), we identified four systems of multiply lensed images (anew) in the redshift range 1.75 <= z <= 4.19. One multiple image system consists of in total eight multiply lensed images of the same source. The analysis based on a parametric mass model derived with the software glafic (Oguri 2010) suggests that the high image multiplicity is due to the source (z_phot = 4.19) being located on a so-called "swallowtail" caustic. In addition to the parametric mass model, we also employed a non-parametric approach using the software PixeLens (Saha and Williams 1997, 2004) in order to reconstruct the projected mass of the cluster using the same strong lensing data input. Both reconstructed mass models agree in revealing several mass components and a highly elliptic shape of the mass distribution. Furthermore, the projected mass inside, for example, a radius R ~35 arcsec ~200 kpc of the cluster for a source at redshift z=1.75 obtained with PixeLens exceeds the glafic estimate within the same radius by about 13 per cent. The difference could be related to the fundamental degeneracy involved when constraining dark matter substructures with gravitationally lensed arcs.
Hybrid ultrahigh resolution optical coherence / photoacoustic microscopy

We present an ultrahigh resolution dual modality optical resolution photoacoustic microsopy (OR-PAM) and spectral domain optical coherence microscopy (SD-OCM) system. The ultrahigh sub-micron lateral resolution is provided by the high numerical aperture of the objective lens used while the ultrahigh axial resolution is provided by the broadband OCT laser that covers 107 nm with a central wavelength of 840 nm. The synchronized simultaneous acquisition for the two modalities is achieved using a 40MHz FPGA. 2D-scanning is realized by two orthogonal translation stages (PI, 400 nm resolution). The transversal resolution of the system is 0.5 μm, the axial resolutions are 30 μm (PAM) and 4 μm (OCM), respectively. The values have been determined experimentally using nanospheres (diameter 10-200nm). For a demonstration of the imaging capability we present images from thin slices of different biological samples as well as in vivo imaging in the zebrafish embryo.
Interval Matrices: Singularity and Real Eigenvalues

This paper proves that a singular interval matrix contains a singular matrix of a very special form. This result is applied to study the real part L of the spectrum of an interval matrix. Under the assumption of sign stability of eigenvectors this paper gives a complete description of L by means of spectra of a finite subset of matrices and formulates a stability criterion for interval matrices with real eigenvalues that requires checking only two matrices for stability.
Normalized coprime factorizations and balancing for unstable nonlinear systems

In this paper we first study the normalized right and left coprime factorizations of a nonlinear system from a state-space point of view. In order to do so, we introduce the notion of inner and co-inner nonlinear systems. Secondly we deal with balancing for unstable nonlinear systems. For linear systems there are several ways to approach this problem, and we generalize the ideas of balancing the normalized coprime factorization and of LQG balancing to the nonlinear case. LQG balancing can be seen as measuring the influence of a state component on a certain future and past energy function. We extend this interpretation to the nonlinear case. Furthermore we use the normalized coprime factorization to give another way of balancing the unstable nonlinear system. We give the relation between these two methods of balancing, which is similar to the relation in the linear case.
Terahertz frequency response of an In0.53Ga0.47As/AlAs resonant‐tunneling diode

We have measured the room‐temperature, broad‐band, terahertz response of a high‐speed In0.53Ga0. 47As/AlAs resonant‐tunneling diode from 120 GHz to 3.9 THz using the free‐electron lasers at UCSB. The ‘‘rectified’’ response is measured with a conventional probe station by using the tungsten probe tip as a whisker antenna. Normalizing the rectified response in the resonant‐tunneling regime with the off‐resonant response we remove the extrinsic frequency dependence controlled by the antenna and the RC time constant and measure an intrinsic relaxation time.
Changes in the planning target volume and liver volume dose based on the selected respiratory phase in respiratory-gated radiation therapy for a hepatocellular carcinoma

The aim of this study was to quantitatively analyze the changes in the planning target volume (PTV) and liver volume dose based on the respiratory phase to identify the optimal respiratory phase for respiratory-gated radiation therapy for a hepatocellular carcinoma (HCC). Based on the standardized procedure for respiratory-gated radiation therapy, we performed a 4-dimensional computed tomography simulation for 0 ∼ 90%, 30 ∼ 70%, and 40 ∼ 60% respiratory phases to assess the respiratory stability (SR) and the defined PTVi for each respiratory phase i. A treatment plan was established, and the changes in the PTVi and dose volume of the liver were quantitatively analyzed. Most patients (91.5%) passed the respiratory stability test (SR = 0.111 ± 0.015). With standardized respiration training exercises, we were able to minimize the overall systematic error caused by irregular respiration. Furthermore, a quantitative analysis to identify the optimal respiratory phase revealed that when a short respiratory phase (40 ∼ 60%) was used, the changes in the PTV were concentrated inside the center line; thus, we were able to obtain both a PTV margin accounting for respiration and a uniform radiation dose within the PTV.
Epitaxial growth of ultra-thin NbN films on AlxGa1−xN buffer-layers

The suitability of AlxGa1−xN epilayers to deposit onto ultra-thin NbN films has been demonstrated for the first time. High quality single-crystal films with 5 nm thickness confirmed by high resolution transmission electron microscopy (HRTEM) have been deposited in a reproducible manner by means of reactive DC magnetron sputtering at elevated temperatures and exhibit critical temperatures (Tc) as high as 13.2 K and residual resistivity ratio (RRR) ∼1 on hexagonal GaN epilayers. On increasing the Al content x in the AlxGa1−xN epilayer above 20%, a gradual deterioration of Tc to 10 K was observed. Deposition of NbN on bare silicon substrates served as a reference and comparison. Excellent spatial homogeneity of the fabricated films was confirmed by R(T) measurements of patterned micro-bridges across the entire film area. The superconducting properties of these films were further characterized by critical magnetic field and critical current measurements. It is expected that the employment of GaN material as a buffer-layer for the deposition of ultra-thin NbN films will prospectively benefit terahertz electronics, particularly hot electron bolometer (HEB) mixers.
Gyrokinetic field theory

The Lagrangian formulation of the gyrokinetic theory is generalized in order to describe the particles’ dynamics, as well as the self-consistent behavior of the electromagnetic fields. The gyrokinetic equation for the particle distribution function and the gyrokinetic Maxwell’s equations, for the electromagnetic fields, are both derived from the variational principle for the Lagrangian consisting of the parts of particles, fields, and their interaction. In this generalized Lagrangian formulation, the energy conservation property for the total nonlinear gyrokinetic system of equations is directly shown from Noether’s theorem. This formulation can be utilized in order to derive the nonlinear gyrokinetic system of equations and the rigorously conserved total energy for fluctuations with arbitrary frequencies. Simplified gyrokinetic systems of equations with the conserved energy are obtained from the Lagrangian with the small electron gyroradii, quasineutrality, and linear polarization–magnetization approxima.
Optimal Excitation of Baroclinic Waves

Abstract Development of perturbations in a baroclinic flow can arise both from exponential instability and from the transient growth of favorably configured disturbances that are not of normal mode form. The transient growth mechanism is able to account for development of neutral and damped waves as well as for an initial growth of perturbations asymptotically dominated by unstable modes at significantly greater than their asymptotic exponential rates. Unstable modes, which are the eigenfunctions of a structure equation, are discrete and typically few in number. In contrast, disturbances favorable for transient growth form a large subset of all perturbations. To assess the potential of transient growth to account for a particular phenomena it is useful to obtain from this subset the initial condition that gives the maximum development in a well-defined sense. These optimal perturbations have a role in the theory of transient development analogous to that of the normal modes in exponential instability theo.
High-mobility thin-film transistor with amorphous InGaZnO4 channel fabricated by room temperature rf-magnetron sputtering

Thin-film transistors (TFTs) were fabricated using amorphous indium gallium zinc oxide (a-IGZO) channels by rf-magnetron sputtering at room temperature. The conductivity of the a-IGZO films was controlled from ∼10−3to10−6Scm−1 by varying the mixing ratio of sputtering gases, O2∕(O2+Ar), from ∼3.1% to 3.7%. The top-gate-type TFTs operated in n-type enhancement mode with a field-effect mobility of 12cm2V−1s−1, an on-off current ratio of ∼108, and a subthreshold gate voltage swing of 0.2Vdecade−1. It is demonstrated that a-IGZO is an appropriate semiconductor material to produce high-mobility TFTs at low temperatures applicable to flexible substrates by a production-compatible means.
Minkowski‐Elektrodynamik als Ergebnis einer feldtheoretischen Untersuchung

Die Kopplung von elektromagnetischem und Materiefeld als Analogisierung der Elektrodynamik in Medien wird allgemein untersucht. Es zeigt sich, das nur die Abtrennung beider Felder im Sinne der Minkowskischen Elektrodynamik sinnvoll ist, wobei ein Minimum an Voraussetzungen verwendet wird. Ein Energietensor von der Struktur des Abrahamschen tritt dabei nirgends auf. Damit durfte von feldtheoretischer Grundlage aus ein Beweis zugunsten des Minkowski-Tensors fur die Mikro- und damit auch fur die Makroverhaltnisse erbracht sein.
Coupling medium for microwave medical imaging applications

Sodium meta silicate gel is proposed as a novel coupling medium with a better coupling and a lesser dielectric loss than the conventionally used media. Dielectric constants between 8 and 20 exhibited for various relative density and pH, makes the material in perfect match with that of the various tissues. It is also useful as a phantom model material in microwave medical imaging.
A new formulation of the linear sampling method: spatial resolution and post-processing

A new formulation of the linear sampling method is described, which requires the regularized solution of a single functional equation set in a direct sum of L2 spaces. This new approach presents the following notable advantages: it is computationally more effective than the traditional implementation, since time consuming samplings of the Tikhonov minimum problem and of the generalized discrepancy equation are avoided; it allows a quantitative estimate of the spatial resolution achievable by the method; it facilitates a post-processing procedure for the optimal selection of the scatterer profile by means of edge detection techniques. The formulation is described in a two-dimensional framework and in the case of obstacle scattering, although generalizations to three dimensions and penetrable inhomogeneities are straightforward.
Canadian Atlantic Storms Program: The Meteorological Field Project

Abstract The field phase of the Canadian Atlantic Storms Program (CASP) was conducted from 15 January to 15 March 1986. The principal objective of the meteorological component of the program was to begin the process of improving the understanding and prediction of mesoscale features within East Coast storms as well as the storms themselves. The project area, instrumentation platforms used, real-time forecasts, and the linkage of the program to the American Genesis of Atlantic Lows Experiment (GALE) are discussed. Sixteen storms were sampled during the field phase. A number of mesoscale features such as fronts, precipitation bands, heavy snow, and freezing precipitation were sampled. These features and the storms themselves will be studied over the next several years. It is anticipated that scientific progress in understanding the nature of these winter systems and experience gained with new forecasting tools will lead to improved weather forecasts.
The stochastic geometry of polymer crystallization processes

The process of crystallization of polyrners may be modelled as a spatially structured counting process, whose intensity kernel depends upon the available free volume. Due to the effect of impingement, an explicit expression for the stochastic occupied volume is difficult to obtain, while derivations of its expected value have been provided since the pioneering work of Kolmogorov and Avrami, in use of chemical engineers. In this paper we provide two theorems which, by the use of stochastic geometry, ensure local and global convergence of the stochastic growth process to its expected value, justifing so the use of deterministic models to predict the results of real experiments. Also consistent statistical estimators of the growth parameters can be provided. Their asymptotic normality gives the possibility to build confidence intervals for their predicted values
Wall-Pressure Spectral Model Including the Adverse Pressure Gradient Effects

4, in both internal (channel) and external (airfoil) flows. A review of the boundary-layer parameters characterizing the pressure gradient effects is provided, and the more relevant ones are introduced as new variables in the model. The method is then compared to the zero pressure gradient model it is derived from. The influence of the pressure gradient on the wall-pressure spectrum is discussed.Finally,themethodisappliedtoprovideinputdataofaradiatedtrailing-edge noisemodelbymeansofan aeroacoustic analogy, namely Amiet’s theory of turbulent boundary layer past a trailing edge. The results are compared to experimental data obtained in an open-jet anechoic wind tunnel.
Complexity of magnetic structures: Flares and cycle phase dependence

A long data set of MDI/SOHO full-disk magnetograms is analyzed to provide a large sample of active regions. The objective is to study the variations of the fractal dimension of these structures on different time scales: in relation to their activity level (spots, flares) and during the solar cycle. First, the variations of the fractal dimension of the structure during solar flares are studied using a very large sample. Variations are found to be of very small amplitude. The complexity of the structures is slightly larger after the flare when considering regions close to the flare (2−3 ◦ ), while a decrease seems to be observed at larger scales (up to 10 ◦ ), although this should be confirmed using other approaches. The results obtained by Meunier (1999a) concerning the fractal dimension versus the size of the structures for various magnetic thresholds are confirmed on a much larger sample, with a peculiar behavior seen around 550−800 Mm 2 . This scale is observed to increase from cycle minimum to cycle maximum. In addition, I observe that the fractal dimension of active regions reaches a plateau above 3000 Mm 2 and that structures of a given size are more complex when they have spots. The fractal dimension is strongly variable during the solar cycle, with the sign of the variation depending on their size and on their flux content (spot or no spot) and with an amplitude up to 0.17 between the ascending phase and cycle maximum.