Miracle-dz/UniFAR-FTUs huggingface dataset:
Natural linearization for the identification of a diffusion coefficient in a quasi-linear parabolic system from short-time observations

We discuss a natural linearization approach to the identification of a diffusion coefficient in a quasilinear parabolic equation from observations of its solution during a short period of time. In this context, a natural linearization means a reduction of the original nonlinear inverse problem to two linear ill-posed problems, when the solution of one of them is used as data for the next one. For both these problems no information concerning solution smoothness is usually given. Therefore, an a posteriori regularization parameter choice strategy should be implemented for their regularization. Even if such a strategy allows an order-optimal regularization parameter choice for the first linear problem, it does not provide us with a reliable regularization error estimate. It means that the data perturbation level for the second linear problem is not given exactly. The main accomplishment of the present paper is to propose a new strategy of the regularization parameter choice which allows an order-optimal regularization of the second linear problem under these circumstances. We also estimate the best possible order of accuracy that in principle can be obtained within a natural linearization approach, and discuss its correlation with known results. Numerical experiments on model problems support a theoretical analysis.
Mixing State of Submicrometer Sea Spray Particles Enriched by Insoluble Species in Bubble-Bursting Experiments

AbstractMeasurements of size distribution, hygroscopicity, and volatility of submicrometer sea spray particles produced by the bubble busting of artificial and natural seawater were conducted to determine their mixing state and volume fractions of hygroscopic and nonhygroscopic species or volatile and nonvolatile species. The particles sprayed from artificial seawater having insoluble silica particles were found to be an external mixture of two groups of particles having hygroscopic growth factors (HGFs) of 1.33 (an internal mixture of nonhygroscopic silica particles and hygroscopic salt species) and 1.68 (a similar mixture having more salt species) when the mass ratio of insoluble particles to dissolved salts was higher than 2. For sea spray particles from natural seawater, the external mixing was not significantly observed because of a high concentration of dissolved salts. The HGFs of sea spray particles (80–140 nm) from natural seawater were in the range of 1.70–1.76, which were lower than from pure a.
Near-limiting gravity waves in water of finite depth

Progressive, irrotational gravity waves of constant form, with all crests in a wave train identical, exist as a two-parameter family. The first parameter, the ratio of mean depth to wavelength, varies from zero (the solitary wave) to infinity (the deep-water wave). The second parameter, the wave height or amplitude, varies from zero (the infinitesimal wave) to a limiting value dependent on the first parameter. Solutions of limiting waves, with angled crests, have been presented in a previous paper; this paper considers near-limiting waves having rounded crests with a very small radius of curvature, in some cases as little as 0.0001 of the water depth. The com puting method is a modification of the integral equation technique used for limiting waves. Two leading terms are again used to give a close approxim ation to the flow near the crest and hence minimize the num ber of subsequent terms needed; the form of these leading terms is suggested by earlier work of G. G. Stokes (Mathematical and physical papers, vol. 1, pp. 225-228. Cambridge University Press (1880)), M. A. G rant (J.F luid Mech. 59, 257-262 (1973)) and L. W. Schwartz Fluid Mech. 62, 553-578 (1974)). To achieve satisfactory accuracy, however, it is now necessary to add a set of dipoles above the crest in the complex potential plane, as previously used by M. S. Longuet-Higgins & M . J . H. Fox (J. Fluid Mech. 80, 721-741 (1977)). The results include the first fully detailed calculations of non-breaking waves having local surface slopes exceeding 30°. The local profile at the crest, despite its very small scale, is shown to tend with increasing wave height to the asymptotic self-similar form previously com puted by Longuet-Higgins & Fox. Their predictions of an ultim ate m aximum slope of 30.37° and a vertical crest acceleration of 0.388g are supported. The results agree well with earlier calculations for steep waves at the two extremes of solitary and deep-w ater waves. In particular, it is confirmed that in the approach to limiting height the phase velocity and certain integral quantities possess not only the well-known m aximum but also a subsequent minimum, the first in the infinite series of extrema predicted theoretically by M. S. Longuet-Higgins & M . J . H. Fox (J. Fluid Mech. 85, 769-786 (1978)). Briefly considered also are the level of action of near-limiting deep-w ater waves, the decay of surface drift velocity from the limiting value and the method established for com puting waves of all lesser heights.
Combinatorial descriptions of homotopy groups of certain spaces

We give a combinatorial description of the homotopy groups of the suspension of a K(π, 1) and of wedges of 2-spheres. In particular, all of the homotopy groups of the 2-sphere are given as the centres of certain combinatorially described groups.
Electric field dependence of a doublet in quantum-paraelectric SrTiO3 studied by brillouin scattering

Abstract Brillouin scattering on SrTiO3 under a DC electric bias field E b (0 ≤E b ≤ 450 V/mm) was performed at T = 25.1 K and T = 28.0 K in order to investigate the origin of the doublet spectra in the quantum paraelectric (QPE) regime. An anomalous behavior of the integrated intensity of the doublet spectra was newly observed. The intensity has a minimum at E b = 260 V/mm (q // [001]), in the vicinity of the transition field from QPE state to induced ferroelectric state. No corresponding anomaly is observed when the scattering vector q is parallel to the [110] direction. These results are discussed in comparison with the second sound interpretation proposed by Hehlen et al., in relation to the ferroelectric soft mode.
Electrostatic ion cyclotron instabilities in negative ion plasmas

The effect of negative ions on the collisionless electrostatic ion cyclotron instability (EICI) is investigated analytically and numerically. The singly ionized negative ion species has mass greater than or equal to the mass of the singly ionized positive ion species. Standard linear Vlasov theory is used to estimate the critical electron drift velocity. It is shown that the critical drifts for the excitation of both the light and heavy ion EIC modes decrease as the relative density of negative ions increases. Our results are compared with available negative ion plasma experiments concerning the EICI, and possible applications to experiments in the ionosphere are briefly discussed.
Adventures in Stochastic Processes

The book reviews section generally accepts for review only those books whose content and level reflect the general editorial policy of Technometrics. Publishers are invited to send books for review to Eric R. Ziegel, Amoco Research Center, Mail Station F-l/C& P.O. Box 3011, Naperville, Illinois 60566-7011. Please include the price of the book. The opinions expressed in this section are those of the reviewers and do not necessarily reflect those of the editorial staff or the sponsoring societies. Listed prices were provided by the publisher when the books were received by Technometrics and may not be current.
STABILIZATION OF SOLUTIONS OF THE THIRD MIXED PROBLEM FOR A SECOND ORDER PARABOLIC EQUATION IN A NONCYLINDRICAL DOMAIN

This paper studies the behavior for large values of time of the solution of the third mixed problem in a noncylindrical domain that expands as increases, for a linear second order parabolic equation in selfadjoint form without lower terms. In this connection the boundary condition is chosen so that the energy conservation law holds. For a very large class of domains a simple geometric characteristic of the domain is singled out-the function , where is the intersection of the domain with the hyperplane - determining the stabilization speed of the solution. Namely, it is proved that a solution of the above problem with initial function from satisfies the estimate 0,$ SRC=http://ej.iop. org/images/0025-5734/39/1/A04/tex_sm_1472_img10. gif/>and the accuracy of this estimate is of the order of the convergence to zero as . Bibliography: 6 titles.
The Collapse of a Gas Bubble near a Solid Wall by a Shock Wave and the Induced Impulsive Pressure

An experimental study concerning the shock wave—bubble interaction was conducted in order to obtain a unified consideration of the mechanism of the impulsive pressure generation induced by the cavitation bubble collapse. It was found that the relation between the maximum impulsive pressure, pG, max, and the relative distance, lc/Re, is closely similar to the known result obtained from a single spark-generated bubble, and that a gas bubble within the region of lc/Re ≤ 7 behaves as a source capable of generating more intensive impulsive pressure than the impact pressure induced by a shock wave impinging directly on a solid wall without the presence of a gas bubble.
Direct 4D-Var Assimilation of NCEP Stage IV Radar and Gauge Precipitation Data at ECMWF

AbstractDirect four-dimensional variational data assimilation (4D-Var) of NCEP stage IV radar and gauge precipitation observations over the eastern United States has been developed and tested in ECMWF’s global Integrated Forecasting System. This is the natural extension of earlier work using a two-step 1D+4D-Var approach. Major aspects of the implementation are described and discussed in this paper. In particular, it is found that assimilating 6-h precipitation accumulations instead of the original hourly data substantially improves the behavior of 4D-Var, especially as regards the validity of the tangent-linear assumption.The comparison of background and analysis precipitation departures demonstrates that most of the information contained in the new precipitation observations is properly assimilated. Experiments run over the periods April–May and September–October 2009 also show that local precipitation forecasts become significantly better for ranges up to 12 h, which indicates that a genuine precipitat.
Estimates of gradient and of Jacobian of harmonic mappings defined in the unit disk

Let F: T → γ be a bounded measurable function of the unit circle T onto a rectifiable Jordan curve γ with the length |γ|, and let w = P[F] be its harmonic extension to the unit disk U. By using the arc length parametrization of γ we obtain the following results: (i) If F is a quasi-homeomorphism and 1 < p < 2, the L P -norm of the Hilbert-Schmidt norm of the gradient of w is bounded as follows: ∥D(w)∥ p < |γ|/4√2(16/π(2-p) 1/p . (ii) If F is p-Lipschitz continuous and γ is Dini smooth, then the Jacobian of w is bounded in U by a constant C(p,γ). The first result is an extension of a recent result of Verchota and Iwaniec, and Martin and Sbordone, while the second result is an extension of a classical result of Martio where γ = T.
Sub-Bergman Hilbert spaces on the unit disk III

For a bounded analytic function $\varphi$ on the unit disk $\D$ with $\|\varphi\|_\infty\le1$ we consider the defect operators $D_\varphi$ and $D_{\overline\varphi}$ of the Toeplitz operators $T_\varphi$ and $T_{\overline\varphi}$, respectively, on the weighted Bergman space $A^2_\alpha$. The ranges of $D_\varphi$ and $D_{\overline\varphi}$, written as $H(\varphi)$ and $H(\overline\varphi)$ and equipped with appropriate inner products, are called sub-Bergman spaces. We prove the following three results in the paper: for $-1<\alpha\le0$ the space $H(\varphi)$ has a complete Nevanlinna-Pick kernel if and only if $\varphi$ is a M\"{o}bius map; for $\alpha>-1$ we have $H(\varphi)=H(\overline\varphi)=A^2_{\alpha-1}$ if and only if the defect operators $D_\varphi$ and $D_{\overline\varphi}$ are compact; and for $\alpha>-1$ we have $D^2_\varphi(A^2_\alpha)= D^2_{\overline\varphi}(A^2_\alpha)=A^2_{\alpha-2}$ if and only if $\varphi$ is a finite Blaschke product. In some sense our restrictions on $\alpha$ here are best possible.
Bootstrap current and neoclassical transport in tokamaks of arbitrary collisionality and aspect ratio

A multi-species fluid model is described for the steady state parallel and radial force balance equations in axisymmetric tokamak plasmas. The bootstrap current, electrical resistivity, and particle and heat fluxes are evaluated in terms of the rotation velocities and friction and viscosity coefficients. A recent formulation of the neoclassical plasma viscosity for arbitrary shape and aspect ratio (including the unity aspect ratio limit), arbitrary collisionality, and orbit squeezing from strong radial electric fields is used to illustrate features of the model. The bootstrap current for the very low aspect ratio National Spherical Torus Experiment [J. Spitzer et al., Fusion Technol. 30, 1337 (1996)] is compared with other models; the largest differences occur near the plasma edge from treatment of the collisional contributions. The effects of orbit squeezing on bootstrap current, thermal and particle transport, and poloidal rotation are illustrated for an enhanced reverse shear plasma in the Tokamak Fusi.
Likelihood Score under Generalized Self-Concordance

We show how, under a generalized self-concordance assumption and possible model misspecification, we can establish non-asymptotic bounds on the normalized likelihood score when using maximum likelihood or score matching. The tail behavior is governed by an effective dimension corresponding to the trace of the sandwich covariance. We also show how our non-asymptotic approach allows us to obtain confidence bounds for the estimator and analyze Rao’s score test
Generation of electricity in GaN nanorods induced by piezoelectric effect

Conversion of mechanical energy into electric energy has been demonstrated in GaN nanorods. The measurement was achieved by deflecting GaN nanorods with a conductive atomic force microscope PtIr tip in contact. The mechanism relies on the coupling between piezoelectric and semiconducting properties in GaN nanorod, which creates a strain field and drives the charge flow across the nanorod. The result shown here opens up an opportunity for harvesting electricity from wasted mechanical energies in the ambient environment, which may lead to the realization of self-powered nanodevices.
Pruning Edges and Gradients to Learn Hypergraphs From Larger Sets

This paper aims for set-to-hypergraph prediction, where the goal is to infer the set of relations for a given set of entities. This is a common abstraction for applications in particle physics, biological systems, and combinatorial optimization. We address two common scaling problems encountered in set-to-hypergraph tasks that limit the size of the input set: the exponentially growing number of hyperedges and the run-time complexity, both leading to higher memory requirements. We make three contributions. First, we propose to predict and supervise the \emph{positive} edges only, which changes the asymptotic memory scaling from exponential to linear. Second, we introduce a training method that encourages iterative refinement of the predicted hypergraph, which allows us to skip iterations in the backward pass for improved efficiency and constant memory usage. Third, we combine both contributions in a single set-to-hypergraph model that enables us to address problems with larger input set sizes. We provide ablations for our main technical contributions and show that our model outperforms prior state-of-the-art, especially for larger sets.
A synthesis of local and eﬀective tax progressivity measurement

This paper examines theoretical properties of local and global measures of income tax progressivity. In particular, consistency property of global measures with local measures is analyzed. Using a normative approach, an index of performance in effective progression underlying a tax system, in relation to that of a ‘norm’, is suggested and analyzed. The norm chosen here is the welfare level associated with the post-tax distribution resulting from an inequality minimizing taxation policy which maintains pre-tax rank orders of tax payers and does not impose any additional tax burden on them, given that the pre-tax distribution is fixed as well. As the actual post-tax welfare increases, effective progression (hence performance) improves, which ensures that it is possible to elevate the level of performance sequentially, as may be desired by a policy maker, towards achieving the norm welfare. JEL classification: D31, D63, H64
The Eﬀect of Banking Risk on Indonesia’s Regional Development Banks

Bank’s financial performance is the representation of its financial condition in particular period of time, either in relation to the fund raising or to the fund allocation, which is usually observed through several indicators, such as capital sufficiency, liquidity, and bank profitability. In the banking industries, profitability is the most accurate indicator to measure the bank performance. Instruments used to measure profitability are Return on Equity (ROE) and Return on Assets (ROA). In this study the effect of Banking Risk is analyze d by using the ratio of Non-Performing Loan (NPL), Net Interest Margin (NIM), Loan to Deposit Ratio (LDR), the ratio of Operational Cost to Operational Income (OCOI/BOPO) to financial performance in Regional Development Banks in Indonesia. The data used in this study were obtained from the Annual Report disseminated in the website of each banks. The number of samples is 26 Regional Development Banks in Indonesia with the period of 2013-2015. The result of this research shows that simultaneously NPL, NIM, LDR, and OBOI/BOPO are significant to ROA; while partially the NPL is significant and negatively affects ROA, NIM is significant and positively influences ROA, LDR is not significant and negatively affects ROA, and OCOI/BOPO is significant and negatively influences ROA. That means the banks have to minimize the ratio of NPL, LDR, and BOPO, for they have a negative influence on ROA. Conversely, banks have to maximize the ratio of NIM because the latter has a positive influence on ROA.
Benchmarking the Effect of Poisoning Defenses on the Security and Bias of the Final Model

Machine learning models are susceptible to a class of attacks known as adversarial poisoning where an adversary can maliciously manipulate training data to hinder model performance or, more concerningly, insert backdoors to exploit at inference time. Many methods have been proposed to defend against adversarial poisoning by either identifying the poisoned samples to facilitate removal or developing poison agnostic training algorithms. Although effective, these proposed approaches can have unintended consequences on other aspects of model performance, such as worsening performance on certain data sub-populations, thus inducing a classiﬁ-cation bias. In this work, we evaluate several adversarial poisoning defenses. In addition to traditional security metrics, i.e., robustness to poisoned samples, we propose a new metric to measure the potential undesirable discrimination of sub-populations resulting from using these defenses. Our investigation highlights that many of the evaluated defenses trade decision fairness to achieve higher adversarial poisoning robustness. Given these results, we recommend our proposed metric to be part of standard evaluations of machine learning defenses.
Impacts of the Green Revolution on Rhizosphere Microbiology Related to Nutrient Acquisition

The Green Revolution (GR) involved selective breeding of cereals and the use of high fertilizer inputs with the goal of increasing crop yields to alleviate hunger. As a result of both greater use of inorganic fertilizers and the introduction of semi-dwarf cultivars, grain yield increased globally and hunger was alleviated in certain areas of the world. However, these changes in varietal selection and fertilization regimes have impacted soil fertility and the root-associated microbiome. Higher rates of inorganic fertilizer application resulted in reduced rhizosphere microbial diversity, while semi-dwarf varieties displayed a greater abundance of rhizosphere microbes associated with nitrogen utilization. Ultimately, selection for beneficial aboveground traits during the GR led to healthier belowground traits and nutrient uptake capabilities.
Planetary nebulae as standard candles. V - The distance to the Virgo Cluster

The O III forbiden 5007-A line fluxes of 486 planetary nebula candidates in six early-type galaxies (NGC 4374, 4382, 4406, 4472, 4486, and 4649) in the core of the Virgo Cluster are identified and measured. Following the procedures and calibrations outlined in previous papers in this series, the observed planetary nebula luminosity functions are compared to an empirical model based on the planetary nebulae in M31, and the distances to the galaxies are derived to be 15.7, 14.4, 15.7, 13.9, 14.5, and 14.2 Mpc. These distances exhibit superb agreement with a dispersion of only 0.8 Mpc and suggest that the cluster depth is less than 2 Mpc. Most importantly, the distances are totally uncorrelated with parent galaxy metallicity, color, UV flux, or Hubble type. 76 refs.
Assessing Children’s Dental Age with Panoramic Radiographs

(1) Background: The aim of the study was to assess the dental age of the subjects and compare it to their chronological age; to assess the dominant tooth for evaluation of dental age; and to investigate possible individual differences between the left and right side of the dental arch. (2) Methods: This study involved evaluating panoramic radiographs of patients aged 7–13 years. A separate assessment was performed for each tooth according to the degree of germ development. Each subject’s dental age was estimated. (3) Results: The study involved evaluating 349 panoramic radiographs. No difference was found between stages of tooth development on the right side and left side. Correlation between the stages of tooth development and the chronological age was found to be highest in the second permanent molar teeth. The age can be predicted with the estimated age of tooth #37 and the gender of the patient. (4) Conclusions: The chronological age of children aged 7–13 may be estimated based on a modified seven-stage London Atlas of tooth development, where the most accurate landmark(s) of use are second molars.
: Siblings’ Shared Humour in Childhood

Humour is a central feature of social interactions in childhood that has received little attention. In a sample of 86 7-year-old children ( M age = 7.82 years, SD = 0.80), we investigated patterns and individual differences in spontaneous humour observed during free play with their older ( M age = 9.55 years, SD = 0.88) or their younger sibling ( M age = 5.87 years, SD = 0.96). W e coded children’s instances, categories, and responses to humour. We investigated the nature of children’s humour on the dyadic and individual level. Humour was common, and siblings’ production of humour was highly interdependent between play partners. Dyadic humour differed according to structural features of the sibling relationship (age, gender composition), and 7-year-old focal children’s humour varied according to gender. Th is study contributes to knowledge regarding the dyadic nature of children’s humour and individual patterns of humour beyond the preschool years.