Miracle-dz/UniFAR-FTUs huggingface dataset:
Altimeter Observation-Based Eddy Nowcasting Using an Improved Conv-LSTM Network

Eddies can be identified and tracked based on satellite altimeter data. However, few studies have focused on nowcasting the evolution of eddies using remote sensing data. In this paper, an improved Convolutional Long Short-Term Memory (Conv-LSTM) network named Prednet is used for eddy nowcasting. Prednet, which uses a deep, recurrent convolutional network with both bottom-up and top-down connects, has the ability to learn the temporal and spatial relationships associated with time series data. The network can effectively simulate and reconstruct the spatiotemporal characteristics of the future sea level anomaly (SLA) data. Based on the SLA data products provided by Archiving, Validation, and Interpretation of Satellite Oceanographic (AVISO) from 1993 to 2018, combined with an SLA-based eddy detection algorithm, seven-day eddy nowcasting experiments are conducted on the eddies in South China Sea. The matching ratio is defined as the percentage of true eddies that can be successfully predicted by Conv-LSTM network. On the first day of the nowcasting, matching ratio for eddies with diameters greater than 100 km is 95%, and the average matching ratio of the seven-day nowcasting is approximately 60%. In order to verify the performance of nowcasting method, two experiments were set up. A typical anticyclonic eddy shedding from Kuroshio in January 2017 was used to verify this nowcasting algorithm’s performance on single eddy, with the mean eddy center error is 11.2 km. Moreover, compared with the eddies detected in the Hybrid Coordinate Ocean Model data set (HYCOM), the eddies predicted with Conv-LSTM networks are closer to the eddies detected in the AVISO SLA data set, indicating that deep learning method can effectively nowcast eddies.
A random evolution related to a Fisher–Wright–Moran model with mutation, recombination and drift

The paper deals with a model of the genetic process of recombination, one of the basis mechanisms of generating genetic variability. Mathematically, the model can be represented by the so‐called random evolution of Griego and Hersch, in which a random switching process selects from among several possible modes of operation of a dynamical system. The model, introduced by Polanska and Kimmel, involves mutations in the form of a time‐continuous Markov chain and genetic drift. We demonstrate asymptotic properties of the model under different demographic scenarios for the population in which the process evolves. Copyright © 2003 John Wiley & Sons, Ltd.
Evidence for dwarf stars at D of about 100 kiloparsecs near the Sextans dwarf spheroidal galaxy

A method is presented for detecting individual, metal-poor, dwarf stars at distances less than about 150 kpc - a method specifically designed to filter out stars from among the much more numerous faint background field galaxies on the basis of broad-band colors. This technique is applied to two fields at high Galactic latitude, for which there are deep CCD data in four bands ranging from 3600 to 9000 A. The field in Sextans probably contains more than about five dwarf stars with BJ not greater than 25.5. These are consistent with being at a common distance about 100 kpc and lie about 1.7 deg from the newly discovered dwarf galaxy in Sextans whose distance is about 85 +/- 10 kpc. The stars lie near the major axis of the galaxy and are near or beyond the tidal radius. The second field, toward the south Galactic pole, may contain up to about five extra-Galactic stars, but these show no evidence for being at a common distance. Possible applications of this type technique are discussed, and it is shown that even very low surface brightness star clusters or dwarf galaxies may be detected at distances less than about 1 Mpc.
Confidence interval estimation for the population coefficient of variation using ranked set sampling: a simulation study

In this paper, an evaluation of the performance of several confidence interval estimators of the population coefficient of variation (τ) using ranked set sampling compared to simple random sampling is performed. Two performance measures are used to assess the confidence intervals for τ, namely: width and coverage probabilities. Simulated data were generated from normal, log-normal, skew normal, Gamma, and Weibull distributions with specified population parameters so that the same values of τ are obtained for each distribution, with sample sizes n=15, 20, 25, 50, 100. A real data example representing birth weight of 189 newborns is used for illustration and performance comparison.
A Simple Sequentially Rejective Multiple Test Procedure

This paper presents a simple and widely ap- plicable multiple test procedure of the sequentially rejective type, i.e. hypotheses are rejected one at a tine until no further rejections can be done. It is shown that the test has a prescribed level of significance protection against error of the first kind for any combination of true hypotheses. The power properties of the test and a number of possible applications are also discussed.
Dynamics of radiative supernova remnants

A high-resolution numerical simulation is used to study the evolution of a SNR evolving in a homogeneous uniform medium. Emphasis is placed on the transition from the adiabatic stage to the radiative pressure-driven snowplow stage, along with the possible further establishment of a momentum-conserving snowplow state. In most cases the momentum-conserving snowplow is found to be delayed beyond the merger of the remnant with the interstellar medium. 39 references.
Nucleated dwarf elliptical galaxies in the Virgo cluster

Using images from a charge-coupled device survey with the Wide Field Camera on the Isaac Newton Telescope, we performed B- and I-band photometry on 156 Virgo cluster dwarf elliptical (dE) galaxies, 25 candidate new cluster dwarfs, and nine candidate field dwarfs. Galaxies were modelled with Sersic profiles, using both 1D χ2 and 2D cross-correlation methods, with nuclei modelled as point sources. The intensity profiles of 50 galaxies previously classified as dE, dE? , or ? are more accurately fitted if a nucleus is included, and this results in the majority of dwarfs now being classified as nucleated dwarf ellipticals (dE,N). Some faint galaxies with B magnitudes of 18–21 have particularly large relative nuclei, while a small number have apparent central dimmings. For cluster dE,N galaxies the nucleus magnitude is correlated with the magnitude of the host galaxy. The profile parameters of dE and dE,N galaxies are not significantly different, and there is no evident discontinuity in relative nucleus size between non-nucleated and nucleated dwarfs, suggesting that they may form a continuum. Nuclei are on average redder than their underlying galaxies, though a spread of relative colours was found, and two-fifths of nuclei are bluer. Formation mechanisms of nuclei are discussed: at least some appear to have formed in an already existing non-nucleated galaxy, though others may have formed simultaneously with their galaxies and subsequently evolved within them.
Estimation of mean particle volume using the set covariance function

Our aim is to estimate the volume-weighted mean of the volumes of three-dimensional ‘particles’ (compact, not-necessarily-convex subsets) from plane sections of the particle population. The standard stereological technique is to place test lines in the plane section, and measure cubed intercept lengths with the two-dimensional particle profiles. This paper discusses more efficient estimators obtained by integrating over all possible placements of the test line. We prove that these estimators have smaller variance than the line transect estimators, and indeed are related to them by the Rao-Blackwell process. In the improved estimators, the cubed intercept length is replaced by a moment of the distance between two points in the section profile. This can be computed as a moment of the set covariance function, which in turn is computable using the fast Fourier transform. We also derive an isoperimetric-type inequality between the improved estimator and the area-weighted 3/2th moment of the profile areas. Finally, we present two practical applications to particles of silicon carbide and to synaptic boutons in brain tissue. We estimate the variance of the technique and the gain in efficiency over line transect techniques; the efficiency improvement appears to be as much as one order of magnitude.
RANDOM ATTRACTOR FOR FRACTIONAL GINZBURG-LANDAU EQUATION WITH MULTIPLICATIVE NOISE

In this paper, we consider the asymptotic behavior of solutions to the stochastic fractional complex Ginzburg-Landau equation with multiplicative noise in one spatial dimensions. We first transfer stochastic fractional Ginzburg-Landau equation into random equation which solutions generate a random dynamical system. Then, we consider the existence of a random attractor for the random dynamical system. At last we estimate the Hausdorff dimension of the random attractor by using linearization and Lyapunov exponents.
Stability of fluid motions

The natural frequencies of small transverse vibration of a finite beam are governed by an eigenvalue problem. When the beam carries a distributed axial load, the axial load can be taken to remain unidi rectional, independent of deformation, or it may be assumed to "follow" the deformation and act tangentially to the deflected beam. In the former case the axial load is conservative and the eigenvalue problem is self-adjoint while in the latter case the load is nonconser- vative and the eigenvalue problem is nonself-adjoint. If the axial load is increased the unbent configuration eventually becomes unstable. In the conservative case the loss of stability is always by buckling (i.e., divergence) while in the nonconservative case it can be by buckling if the beam is supported at both ends or it can be by oscillations of fixed frequency and increasing amplitude (i.e., flutter) if the beam has a free end. In both cases approximate solutions to the eigenvalue problem can be obtained by applying direct variational methods usually associated with the names of Rayleigh, Ritz, and Galerkin. The present book represents the results of the author's investiga tions into the problem of proving convergence of Galerkin's method when applied to follower-force systems. Extensions of the Ritz and Galerkin methods are established for follower-force systems which preserve the well-known interrelationships that these methods have for conservative systems. The central contributions of the book are careful detailed proofs of the convergence of these methods, first for conservative systems, and then for follower-force systems. In addition convergence is also discussed for some related methods (method of moments, harmonic balance method, Grammel's method, and Trefftz's method) and for hybrid Ritz and Galerkin methods based on simultaneous treatment of the given system and its adjoint. Al most developments framed in of the
FLUCTUATION-ENHANCED GAS SENSING BY SURFACE ACOUSTIC WAVE DEVICES

This paper presents a new method for the detection, identification and quantitative analysis of gas molecules and their mixtures. The enhanced sensitivity and selectivity of this method allows the detection and identification of gases in amounts not previously detectable. This method is based on the spectral analysis of the dynamics of adsorbed molecules on surface acoustic wave (SAW) delay lines and resonators.
Solar Radio Radiation Bursts on 1998 April 15

We present two remarkable "decimetric pulsation" events (DCIM) around the time 1998 0415 0800, detected by spectrometers (1.00-2.00 GHz and 2.60-3.80 GHz) at Beijing Astronomical Observatory (BAO). High-resolution dynamic spectra reveal various fine structures, such as spike groups, pulsations, type-Ill bursts, patches, and zebra patterns or evolving emission lines on the rising phase of the second DCIM around 3 GHz. It is the first time that such a wealth of fine features have been detected in a same type IV-DCIM event; it is also the first time that blips pairs simultaneously drifting towards the same frequency have been recorded; it is the second time to observe an evolving emission line, and the first above 1 GHz.
An analysis of existing data for Wair, Ic and the product Wairsc,air

An analysis is made of the published results of over forty experiments that have determined either the mean energy Wair required to create an ion pair in dry air, the mean excitation energy Ic for graphite, or the product of Wair and the electron stopping-power ratio sc,air for graphite and air for 60Co gamma radiation. A minimization process is used in which the best estimates for Wair and sc,air are those that minimize the sum of the deviations, taking uncertainties into account. This approach yields self-consistent values for Wair, sc,air and the product Wairsc,air. The results of this process are the values Wair = 33.97 eV with standard uncertainty 0.11 eV, sc,air = 0.9926 for 60Co, with relative standard uncertainty 0.32%, and the product Wairsc,air = 33.72 eV for 60Co with standard uncertainty 0.08%. The resulting value for Ic depends on the treatment of the density effect in graphite, the best estimate being the value Ic = 81.1 eV with standard uncertainty 2.0 eV obtained when using the grain density in the evaluation of the graphite stopping power. The robustness of the analysis and the consequences for air-kerma primary standards for radiation dosimetry are discussed.
From graphene to graphite : Electronic structure around the K point

Within a tight-binding approach we investigate how the electronic structure evolves from a single graphene layer into bulk graphite by computing the band structure of one, two, and three layers of graphene. It is well known that a single graphene layer is a zero-gap semiconductor with a linear Dirac-like spectrum around the Fermi energy, while graphite shows a semimetallic behavior with a band overlap of about $41\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$. In contrast to a single graphene layer, we show that two graphene layers have a parabolic spectrum around the Fermi energy and are a semimetal like graphite; however, the band overlap of $0.16\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ is extremely small. Three and more graphene layers show a clear semimetallic behavior. For 11 and more layers the difference in band overlap with graphite is smaller than 10%.
Fundamental properties of field emission-driven direct current microdischarges

For half a century, it has been known that the onset of field emission in direct current microdischarges with gap sizes less than 10 μm can lead to breakdown at applied voltages far less than predicted by Paschen's law. It is still unclear how field emission affects other fundamental plasma properties at this scale. In this work, a one-dimensional fluid model is used to predict basic scaling laws for fundamental properties including ion density, electric field due to space charge, and current-voltage relations in the pre-breakdown regime. Computational results are compared with approximate analytic solutions. It is shown that field emission provides an abundance of cathode electrons, which in turn create large ion concentrations through ionizing collisions well before Paschen's criterion for breakdown is met. Breakdown due to ion-enhanced field emission occurs when the electric field due to space charge becomes comparable to the applied electric field. Simple scaling analysis of the 1D Poisson equation de.
Transformation of shock compression pulses in glass due to the failure wave phenomena

A method of observing the compressive failure waves in glass is presented. Its advantages are good reproducibility of the recorded data and capabilities of measuring, the kinematic parameters of the failure wave and determining by one shot the failure threshold. The experiments presented herein confirm that the network of growing cracks in shock-compressed glass may indeed be considered as a failure wave with a small stress increment. Transformation was observed of the elastic compression wave followed by the failure wave in a thick glass plate into a typical two-wave configuration in a pad of thin glass plates.
Does confined turbulent convection ever attain the ‘asymptotic scaling’ with 1/2 power?

We examine turbulent thermal convection at very high Rayleigh numbers using helium gas in a cylindrical container of diameter-to-height aspect ratios of 1 and 4, and confirm that the Nusselt number, Nu, follows an approximately 1/3 power of the Rayleigh number, Ra, up to some value of Ra that depends on various experimental conditions, such as the nearness to the critical point of helium as well as the aspect ratio. An enhancement of heat transport occurs for higher Ra, coinciding with a substantial increase in Prandtl number as well as in various measures of Boussinesq conditions, and marking the transition from the region in which Nu≈0.064Ra1/3 to another in which Nu≈0.078Ra1/3. By necessity, the Nusselt number in the transition region increases more steeply than 1/3. The transitional slope, which happens to be close to 1/2, does not occur at unique values of Ra for given Pr and so should not be mistaken for the ‘ultimate regime’ of Kraichnan. By comparing various experiments performed under different conditions (but in the apparatus with the same horizontal surfaces), we empirically find that substantially negative values of a non-dimensional parameter related to fluid conductivity and viscosity correlate well with the observed enhancement of heat transport.
Global Drought Watch from Space

Abstract Drought is the most damaging environmental phenomenon. During 1967–91, droughts affected 50% of the 2.8 billion people who suffered from weather-related disasters. Since droughts cover large areas, it is difficult to monitor them using conventional systems. In recent years the National Oceanic and Atmospheric Administration has designed a new Advanced Very High Resolution Radiometer- (AVHRR) based Vegetation Condition Index (VCI) and Temperature Condition Index (TCI), which have been useful in detecting and monitoring large area, drought-related vegetation stress. The VCI was derived from the Normalized Difference Vegetation Index (NDVI), which is the ratio of the difference between AVHRR-measured near-infrared and visible reflectance to their sum. The TCI was derived from the 10.3–11.3-mm AVHRR-measured radiances, converted to brightness temperature (BT). Algorithms were developed to reduce the noise and to adjust NDVI and BT for land surface nonhomogeneity. The VCI and TCI are used to determine.
Distribution Functions to Represent Center-pivot Water Distribution

The manufacturers of center-pivot systems widely use the Christiansen Uniformity coefficient to compare the irrigation uniformities. This single coefficient compares systems but does not provide a functional relationship of the variation of applied depths. The analysis of deficit and excess irrigation amounts requires a distribution function. Field catch can tests of center-pivot systems are used to estimate distribution functions. The four distribution functions investigated were normal, lognormal, uniform, and specialized power. It is concluded that the normal function is the best of the four functions to characterize the distribution of center-pivot systems. The volume of water applied in deficit of and excess to crop requirements is estimated with the normal distribution function.
The dissociative photoionization of methane in the VUV

The dissociative photoionization of CH4 and CD4 has been studied using synchrotron radiation within the energy range of 12-60 eV. The mass spectra of secondary CHn+/CDn+ ions have been found to display significant isotope effects and to depend on the target gas temperature. The kinetic energy spectra of the fragment protons and deuterons have also been determined and it is shown that, in addition to direct photoionization, intermediate, superexcited states play an important role in the photodissociative ionization process.
CLASSIFICAÇÃO DA SUSTENTABILIDADE DAS UNIDADES DE PRODUÇÃO AGRÍCOLA NO PERÍMETRO IRRIGADO ARARAS NORTE, CEARÁ

The aim of this study was to identify the determinant sustainability factors in agricultural production units in the Araras North Irrigated District, as well as to develop a sustainability index applying multivariate statistical technique. The approach was based on a cross-over form applied to 47 irrigators that live in the Araras North Irrigated District located in the uplands of the Acarau watershed, Ceara, Brazil . According to the results the family education level was the major factor in determining the sustainability of the agricultural production units in the Araras North Irrigated District. The second factor was mainly related to the trade processes (selling difficulties and production transportation); while the third one was defined by the variables that express the irrigator’s family condition (the youth of the community involvement and their interest in continuing the agricultural activities). The last factor was pointed out by variables related to natural resources conservation technique. The developed Sustainability Index from selected determinant factors registered that 27.7% of the agricultural production units were classified as sustainables, 25.5% presented a threatened sustainability and 14.9% had a compromised sustainability. Among the 47 units, 11 were classified as unsustainable, which represents 23.4% of them.
Space–time structure of mesoscale motions in the stable boundary layer

In this article, we examine the stochastic characteristics of non‐turbulent motions in the stable boundary layer. The behaviour of mesoscale motions in the atmospheric stable boundary layer is poorly understood beyond case studies of unusually well‐defined events or monotonic waves. Eight networks of wind observations are analysed in order to examine stochastically the space–time characteristics of such motions in the stable boundary layer. The networks include a variety of surface conditions and network configurations, although none of the networks is optimal for our studies. Collectively, the networks allow examination of scales from tens of metres to tens of kilometres.
SIGMOIDAL ACTIVE REGION ON THE SUN: COMPARISON OF A MAGNETOHYDRODYNAMICAL SIMULATION AND A NONLINEAR FORCE-FREE FIELD MODEL

In this paper we show that when accurate nonlinear force-free field (NLFFF) models are analyzed together with high-resolution magnetohydrodynamic (MHD) simulations, we can determine the physical causes for the coronal mass ejection (CME) eruption on 2007 February 12. We compare the geometrical and topological properties of the three-dimensional magnetic fields given by both methods in their pre-eruptive phases. We arrive at a consistent picture for the evolution and eruption of the sigmoid. Both the MHD simulation and the observed magnetic field evolution show that flux cancellation plays an important role in building the flux rope. We compute the squashing factor, Q, in different horizontal maps in the domains. The main shape of the quasi-separatrix layers (QSLs) is very similar between the NLFFF and MHD models. The main QSLs lie on the edge of the flux rope. While the QSLs in the NLFFF model are more complex due to the intrinsic large complexity in the field, the QSLs in the MHD model are smooth and possess lower maximum value of Q. In addition, we demonstrate the existence of hyperbolic flux tubes (HFTs) in both models in vertical cross sections of Q. The main HFT, located under the twisted flux rope in both models, is identified as the most probable site for reconnection. We also show that there are electric current concentrations coinciding with the main QSLs. Finally, we perform torus instability analysis and show that a combination between reconnection at the HFT and the resulting expansion of the flux rope into the torus instability domain is the cause of the CME in both models.