Miracle-dz/UniFAR-FTUs huggingface dataset:
Convective instability of stably stratified water in the ocean

A recent theoretical description of interactions between surface waves and currents in the ocean is extended to allow density stratification. The interaction leads to a convective instability even when the density stratification is statically stable. An unspecified random surface wave field is permitted provided that it is statistically stationary. The instability can be traced to torques produced by variations of a ‘vortex force’. Non-diffusive instabilities produced by this mechanism in water of infinite depth are explored in detail for arbitrary distributions of the destabilizing force. Stability is determined by an eigenvalue problem formally identical to that determining normal modes of infinitesimal internal waves in fluid with a density profile that is not monotone and thereby has a statically unstable region. Some tentative remarks are offered about the problem when dissipation is allowed. Application of the present theory to Langmuir circulations is discussed. Also, according to the present theory, internal wave propagation should be modified by the vortex force arising from the interaction between the surface waves and the current.
Some Distributional Properties of a Brownian Motion with a Drift and an Extension of P. Lévy's Theorem

The theorem proved by P. Levy states that $(\sup B-B,\,\sup B){\;\stackrel{\rm law}{=}\;}(|B|,\,L(B))$. Here, B is a standard linear Brownian motion and $L(B)$ is its local time in zero. In this paper, we present an extension of P. Levy's theorem to the case of a Brownian motion with a (random) drift as well as to the case of conditionally Gaussian martingales. We also give a simple proof of the equality $2\sup B^{\lambda}-B^{\lambda}{\;\stackrel{\rm law}{=}\;}|B^{\lambda}|+L(B^{\lambda})$, where $B^{\lambda}$ is the Brownian motion with a drift ${\lambda}\in\bR$.
Diffusion percolation. I. Infinite time limit and bootstrap percolation

Several models for the dynamic growth of percolation clusters, or 'diffusion percolation' (DP), are introduced and analysed. In these models a random walker (an 'ant') walks on percolation clusters (which are occupied with initial site concentration, pi). The 'ant' is allowed to step off such clusters and add new sites to them if certain conditions are met. Some of these models are shown to have a one-to-one correspondence with models of bootstrap percolation (BP), in which sites which do not have a required number of neighbours are successively culled. Two new percolation thresholds have been calculated for two diffusion percolation models on the square lattice.
Production of Short-Lived Positron-Emitting Radioactive Nuclei Using a 2.4 TW, 50 fs Tabletop Laser

We produced a short-lived positron-emitting radioisotope 13N by using MeV-order deuterons emitted from relativistic laser plasma generated by a tabletop laser. For generation of the plasma, laser pulses with a peak power of 2.4 TW and a pulse duration of 50 fs were focused with a 10 Hz repetition rate onto a microporous polytetrafluoroethylene film loaded with deuterated polystyrene, where the maximum intensity at the focal point was 3 ×1018 W/cm2. The irradiation of melamine resins by deuterons for 55 s produced 13N of 1.00 ±014 Bq through a nuclear reaction of 12C(d,n)13N. This is the first report on an actual activation using a table-sized femtosecond laser.
Ion energy balance in Ohmically heated PLT discharges

Radial profiles of the ion temperature have been measured on PLT by using neutron flux Doppler broadening of oxygen, carbon and helium line radiations, and charge exchange. The ion temperature (⪅ 1.2 keV) is consistent with Hinton-Rosenbluth neoclassical heat conduction in the plateau regime as the dominant energy loss from the plasma with central ion energy confinement times ⪅ 0.1 s.
Volume Flow Rate Calculation Model of Non-Full Pipe Multiphase Flow Based on Ultrasonic Sensors

In the oil and gas industry, it is crucial to employ appropriate drilling fluids to maintain equilibrium of formation pressure throughout the various stages of drilling operations. During the recycling process, the drilling fluid may precipitate gas and as a result, exhibit non-full pipe flow upon return to the surface. Accurate measurement of the volume flow rate of it is imperative in obtaining valuable information from the bottom of the well. Commonly, on-site drilling operations use a multiphase target flowmeter in conjunction with an empirical model to rectify calculation results. Therefore, the theoretical potential of utilizing non-contact ultrasonic sensors for measuring multiphase volume flow rate of non-full pipe flow is significant. In this research, an apparent flow velocity calculation model was established by integrating the ultrasonic Doppler shift model and pipeline fluid mechanics utilizing a four-channel ultrasonic array. Subsequently, the invariant scattering convolution -long short-term memory network was trained on the data-fused ultrasonic signal to identify the liquid level. The velocity-area method was also employed to establish a new multiphase volume flow calculation model. To evaluate the validity of the proposed model, comparison experiments of liquid single-phase flow and liquid-solid two-phase flow were conducted. The experimental results show that, compared with the comparative flow measurement system (CFMS), the accuracy of the ultrasonic flow measurement system (UFMS) is reduced by 0.965%, the nonlinear error (NLE) by 2.293 %, the average relative error (ARE) by 2.570 %, the standard deviation (SD) by 1.395, and the root mean square error (RMSE) by 14.394.
Stochastic optimization of unit commitment: a new decomposition framework

This paper presents a new stochastic decomposition method well-suited to deal with large-scale unit commitment problems. In this approach, random disturbances are modeled as scenario trees. Optimization consists in minimizing the average generation cost over this "tree-shaped future". An augmented Lagrangian technique is applied to this problem. At each iteration, nonseparable terms introduced by the augmentation are linearized so as to obtain a decomposition algorithm. This algorithm may be considered as a generalization of price decomposition methods, which are now classical in this field, to the stochastic framework. At each iteration, for each unit, a stochastic dynamic subproblem has to be solved. Prices attached to nodes of the scenario trees are updated by the coordination level. This method has been applied to a daily generation scheduling problem. The use of an augmented Lagrangian technique, provides satisfactory convergence properties to the decomposition algorithm. Moreover, numerical simulations show that compared to a classical deterministic optimization with reserve constraints, this new approach achieves substantial savings.
Multidimensional Adaptive Testing with a Minimum Error-Variance Criterion

Adaptive testing under a multidimensional logistic response model is addressed. An algorithm is proposed that minimizes the (asymptotic) variance of the maximum-likelihood estimator of a linear combination of abilities of interest. The criterion results in a closed-form expression that is easy to evaluate. In addition, it is shown how the algorithm can be modified if the interest is in a test with a "simple ability structure". The statistical properties of the adaptive ML estimator are demonstrated for a two-dimensional item pool with several linear combinations of the abilities.
Transforming random elements and shifting random fields

Consider a locally compact second countable topological transformation group acting measurably on an arbitrary space. We show that the distributions of two random elements X and $X'$ in this space agree on invariant sets if and only if there is a random transformation $\Gamma$ such that $\Gamma X$ has the same distribution as $X'$. Applying this to random fields in d dimensions under site shifts, we show further that these equivalent claims are also equivalent to site-average total variation convergence. This convergence result extends to amenable groups.
Improved Relative Term Frequency Probability Feature Selection for Document Categorization

Feature selection is an important process to choose a subset of features relevant to a particular application in document classification. Those terms which occur unevenly in various categories have strong distinguishable information as to categorization. Firstly, based on the categorical document frequency probability (CTFP), a CTFP_VM feature selection algorithm was designed for feature selection. Secondly, a maximum term frequency conditional distribution factor was proposed to improve the CTFP_VM criterion further. We perform the document categorization experiments on SVM classifiers with the well-known Reuters-21578 and 20news-18828 corpuses as unbalanced and balanced corpus respectively. Experiments compare the novel methods with other conventional feature selection algorithms and the proposed method achieves the excellent feature set for document categorization.
Hyaluronic acid alone versus hyaluronic acid associated with adelmidrol for Intra-articular treatment of knee osteoarthritis: A long-term follow-up

Background: Hyaluronic acid (HA) has been used for many years for intra-articular treatment of knee osteoarthritis with satisfactory results. HA associated with Adelmidrol – an anti-neuroinflammatory compound – have been only recently introduced in orthopedic clinical practice with good preliminary results. Objective: To investigate whether HA associated with Adelmidrol provides better results than HA alone. Methods: Two cohorts of patients with moderate knee osteoarthritis were treated. Cohort 1 received 5 weekly intra-articular injections of HA during 2017 while Cohort 2, 4 weekly intra-articular injections of HA associated with Adelmidrol during 2018. The patients of the two Cohorts were assessed by WOMAC scale, SF-12 questionnaire and PGIC scale at 1 week (T0), 6 months (T1), 1 year (T2), and 2 years (T3) after the end of treatment. All the data were statistically analyzed. A p-value of <0.05 was considered statistically significant. Results: According to the WOMAC Scale Cohort 1 had higher mean scores than Cohort 2 at each follow-up time, with a statistically significant difference between the two cohorts at T3 (p<0.03) for all the WOMAC components, except for Stiffness. WOMAC Total mean score worsened statistically significantly only in Cohort 1, from T1 to T3 (T2 vs T1: p=0.0033; T3 vs T2: p=0.0007). The same happened for WOMAC Physical Function (T2 vs T1: p=0.0146; T3 vs T2: p=0.0046) and WOMAC Pain (T2 vs T1: p=0.0004; T3 vs T2: p=0.0002). WOMAC Stiffness worsened statistically significantly in Cohort 1 from T2 to T3 (T3 vs T2: p=0.0041), while in Cohort 2 no change on WOMAC scale was statistically significant at any time-point, for any components. The mean scores of the SF-12 questionnaire were better in Cohort 2 than in Cohort 1 at each follow-up time for both the Physical and the Mental components, with a statistically significant difference between the two groups for the latter, at T0 (p=0.0001). In both cohorts the mean score of the Physical component decreased from T0 to T3, but the difference was not statistically significant between the two groups (p=0.25). The mean score of the Mental component slightly increased in Cohort 1 and decreased in Cohort 2, without statistically significant differences between the two groups at any time-point. PGIC showed that Cohort 2 scored significantly better than Cohort 1 at T3 (p=0.0336). Conclusions: Overall, HA associated with Adelmidrol gave better long-term results than HA alone. KEY WORDS: Hyaluronic acid, Adelmidrol, Palmitoylethanolamide, Knee, Osteoarthritis, Synovitis, Mastocytes, Intra-articular injections, Visco-induction.
Dynamic Analysis of Eccentrically Prestressed Damped Beam under Moving Harmonic Force Using Higher Order Shear Deformation Theory

The dynamic behavior of an eccentrically prestressed simply supported beam under a moving harmonic force is studied by using the higher order shear deformation theory in this paper. The prestressed tendon is assumed straight and unbonded with the concrete. The Lagrange’s equations are used to examine the dynamic response of the beam. Trial functions denoting the deflection of the beam and the rotation of the cross sections are expressed in polynomial forms. The Kelvin-Voigt model for the material of the beam is used. By using Lagrange’s equations, the problem is reduced to a system of differential equations and they are solved by using the direct time integration. Convergence study is performed. The effects of an eccentric and an axial prestress force, velocity of a moving harmonic force, excitation frequency, shear deformation, and the viscous damping of the material on the deflection of the beam are examined.
An enhanced text classification model by the inverted attention orthogonal projection module

ABSTRACT The orthogonal projection method has made significant progress in text classification, especially in generating discriminative features. This method obtains more pure and suitable for classification features by projecting text features onto the orthogonal direction of common features (which are not helpful for classification and actually confuse performance). However, this approach requires an additional branch network to generate these common features, which reduces the flexibility of this method compared to representation optimisation methods such as self-attention mechanisms, as it requires significant modification of the base network structure to use. To address this issue, this paper proposes the Inversed Attention Orthogonal Projection Module (IAOPM). IAOPM uses inversed attention (IA) to iteratively reverse the attention map on text features, encouraging the network to remove discriminating features from the text features and obtain potential common features. Unlike the original orthogonal projection method, IAOPM can extract common features within a single network without any branch networks, increasing the flexibility of the orthogonal projection method. We also use an orthogonal loss to ensure the quality of the common features during training, so IAOPM also has better purity performance than the original method. Experiments show that text classification models based on IAOPM outperform the baseline models, self-attention mechanisms, and the original orthogonal projection method on multiple text classification datasets with an average accuracy increase of 1.02%, 0.44%, and 0.52%, respectively.
Approximate Conserved Quantities of Conservative Dynamical Systems in R 3

Approximate generalized symmetries associated with the resonances of conservative dynamical systems in R 3 have been discussed. It has been shown that an approximate first integral (conserved quantities) can be found from the knowledge of two conservative approximate symmetries. Furthermore, the result has been applied to a physical system. Invariant curves have been obtained analytically and they have been compared with the numerical ones on the Poincaré surface of section. Approximate conserved quantity pinpoints the type of stability.
Evaluating the impact of lifelong education on older adults: A case study from Hong Kong

In light of its low fertility rate and long life span, Hong Kong is facing the challenge of a rapidly ageing population. To foster successful ageing, learning throughout life regardless of age is promoted as lifelong learning. A total of 20 older adults who are studying the Diploma in Active Ageing at the School of Professional Education and Executive Development of The Hong Kong Polytechnic University participated in a questionnaire survey while 16 older adult students participated in individual in-depth interviews in the present study. The results show that those who have received both informal and formal learning opportunities experienced positive changes to their physical, psychological and social health. The participants reported that the current lifelong learning policy provides insufficient financial support and insufficient promotion of formal education for older adults. For older adults to pursue further education, there is a need to provide more generous subsidies and relax age eligibility restrictions. To sustain lifelong learning, both informal and formal education for older adults should be promoted equally in order to meet the diverse interests and ability of older learners.
Complex Aggregative Multi-Minima Models for Ferroelastic Transitions in Crystals

The specific features of the thermodynamics of the crystals with particles situated in potential wells of different depths are considered in the framework of 1 + 4 minima model. The deepest central well in it is surrounded by four lateral wells which comprise the set of the equivalent crystallographic positions. We show that in such crystals the isostructural phase transitions and strong anomalies in the absence of transition can appear. Also the ordered phase can emerge without the local stability loss of the initial one.
Electrical transport in ZnCdS films deposited by spray pyrolysis

Electrical transport has been analyzed by thermoelectric power measurements on thin films of ZnxCd1−xS deposited by spray pyrolysis for values of x between 0 and 0.35. The electron density decreases exponentially with x in the as‐deposited films, and the observed more rapid increase of resistivity between 0.10 and 0.20 is caused by a decrease in electron mobility. The mobility activation energy Eμ measured by the difference (Eσ−ES) is essentially constant for x=0 to x=0.27 in as‐deposited films with Eμ of about 0.14 eV. Heat treatment in H2 is effective in reducing the resistivity, primarily through an increase in electron mobility for low x, and primarily through an increase density for high x. A resistivity of 4.0×102 Ω cm has been obtained for x=0.35.
Unimodality of the Distribution of an Order Statistic

A distribution function G(x), on the real line, is called unimodal if there exists a value x = a, such that G(x) is convex for x a. Given that G(x) is unimodal, a condition is given for the unimodality of Gr(x), where r denotes a positive integer. Gr(x) represents the distribution function of the largest observed value in a sample of r observations from the distribution G(x). Some of the standard distributions, such as, the normal, gamma, Poisson and binomial distributions satisfy the given condition. An application of the given result to a' problem of estimating the largest parameter is given.
In Vitro Antiplasmodial, Cytotoxicity, and Antioxidant Activities of Lophira lanceolata (Ochnaceae): A Cameroonian Plant Commonly Used to Treat Malaria

Background Malaria is the leading cause of morbidity and mortality in African countries. We aimed this study at evaluating the in vitro antiplasmodial, antioxidant, and cytotoxicity activity of Lophira lanceolata extracts. Method The aqueous and ethanol extracts were obtained by maceration. It tested in vitro the extracts against Plasmodium falciparum 3D7 and multiresistance Dd2. Macrophage cell lines (RAW 264.7 cells) and red blood cells were used for cytotoxicity tests. The antioxidant activity was assessed by 1,1-diphenyl-2-picrylhydrazine (DPPH), hydrogen peroxide (H2O2), nitric oxide (NO) reduction, and ferric reducing antioxidant power (FRAP) scavenging. Results The in vitro antiplasmodial results showed that the ethanol extract was the most active, with IC50 of 24.51 ± 4.77 µg/mL and 31.86 ± 3.10 µg/mL, respectively, on the resistant Dd2 and sensitive 3D7 strains unlike the aqueous which indicated moderate activity with an IC50 of 51.36 ± 4.86 μg/mL and 56.36 ± 4.27 μg/mL, respectively, on the resistant Dd2 and sensitive (3D7) strains. However, the ethanol extract had the highest activity, with an IC50 of 8.153 g/mL, 1915 g/mL, 30.81 g/mL, and 54.66 g/mL, respectively, for DPPH, H2O2, NO, and FRAP, while the aqueous extract had an IC50 of 6.724, 2387681, 185.7, and 152.0 g/mL, respectively, for DPPH, H2O2, NO, and FRAP. The cytotoxicity test reveals that both extracts do not promote red blood cell haemolysis. They presented weak activity against RAW 264.7 cells and red blood cells. Conclusion According to these findings, the aqueous and ethanol extracts have antiplasmodial and antioxidant activity but with no cytotoxic effects on red blood cells or RAW cells. However, it will be important to investigate the in vivo antiplasmodial and antioxidant activity of these extracts.
All-optical Bose-Einstein condensation using a compressible crossed dipole trap

We describe an all-optical method of making a {sup 87}Rb Bose-Einstein condensate (BEC). Atoms are first cooled in an optical lattice and loaded into a crossed dipole trap with 1.06 {mu}m light. Then the density is increased by dynamically reducing the trap size, while the atoms are evaporatively cooled by reducing the light intensity. Every 3.3 s, we obtain a nearly pure BEC with 3.5x10{sup 5} atoms in their lowest internal energy state.
Unsupervised convolutional autoencoders for 4D transperineal ultrasound classification

Abstract. Purpose 4D Transperineal ultrasound (TPUS) is used to examine female pelvic floor disorders. Muscle movement, like performing a muscle contraction or a Valsalva maneuver, can be captured on TPUS. Our work investigates the possibility for unsupervised analysis and classification of the TPUS data. Approach An unsupervised 3D-convolutional autoencoder is trained to compress TPUS volume frames into a latent feature vector (LFV) of 128 elements. The (co)variance of the features are analyzed and statistical tests are performed to analyze how features contribute in storing contraction and Valsalva information. Further dimensionality reduction is applied (principal component analysis or a 2D-convolutional autoencoder) to the LFVs of the frames of the TPUS movie to compress the data and analyze the interframe movement. Clustering algorithms (K-means clustering and Gaussian mixture models) are applied to this representation of the data to investigate the possibilities of unsupervised classification. Results The majority of the features show a significant difference between contraction and Valsalva. The (co)variance of the features from the LFVs was investigated and features most prominent in capturing muscle movement were identified. Furthermore, the first principal component of the frames from a single TPUS movie can be used to identify movement between the frames. The best classification results were obtained after applying principal component analysis and Gaussian mixture models to the LFVs of the TPUS movies, yielding a 91.2% accuracy. Conclusion Unsupervised analysis and classification of TPUS data yields relevant information about the type and amount of muscle movement present.
Rayleigh--Taylor and Richtmyer--Meshkov instabilities in finite-thickness fluid layers

Rayleigh–Taylor (RT) and Richtmyer–Meshkov (RM) instabilities are considered in a fluid layer of thickness t having perturbations of arbitrary wave number k at either one or both interfaces. The evolution of the perturbation amplitudes η1,2(τ), τ =time, is given analytically in terms of a coupling angle θ which measures the strength of the coupling between interfaces 1 and 2. A new type of freeze‐out in shocked layers is reported according to which, the proximity of the two interfaces can, under proper conditions, lead to the complete freeze‐out of one, but not both, perturbations. For example, to freeze the first interface one needs η1(0)/η2(0)= sin θ. Freeze‐out cannot be achieved in the RT case; instead, one can kill one of the modes. For example, setting η1(0)/η2(0)= tan(θ/2) will kill the exponentially growing mode, leaving only the oscillatory mode at both interfaces.