Miracle-dz/UniFAR-FTUs huggingface dataset:
Numerical simulations for full history recursive multilevel Picard approximations for systems of high-dimensional partial differential equations

One of the most challenging issues in applied mathematics is to develop and analyze algorithms which are able to approximately compute solutions of high-dimensional nonlinear partial differential equations (PDEs). In particular, it is very hard to develop approximation algorithms which do not suffer under the curse of dimensionality in the sense that the number of computational operations needed by the algorithm to compute an approximation of accuracy $\epsilon > 0$ grows at most polynomially in both the reciprocal $1/\epsilon$ of the required accuracy and the dimension $d \in \mathbb{N}$ of the PDE. Recently, a new approximation method, the so-called full history recursive multilevel Picard (MLP) approximation method, has been introduced and, until today, this approximation scheme is the only approximation method in the scientific literature which has been proven to overcome the curse of dimensionality in the numerical approximation of semilinear PDEs with general time horizons. It is a key contribution of this article to extend the MLP approximation method to systems of semilinear PDEs and to numerically test it on several example PDEs. More specifically, we apply the proposed MLP approximation method in the case of Allen-Cahn PDEs, Sine-Gordon-type PDEs, systems of coupled semilinear heat PDEs, and semilinear Black-Scholes PDEs in up to 1000 dimensions. The presented numerical simulation results suggest in the case of each of these example PDEs that the proposed MLP approximation method produces very accurate results in short runtimes and, in particular, the presented numerical simulation results indicate that the proposed MLP approximation scheme significantly outperforms certain deep learning based approximation methods for high-dimensional semilinear PDEs.
Creative Artificial Intelligence - Algorithms vs. humans in an incentivized writing competition

The release of openly available, robust text generation algorithms has spurred much public attention and debate, due to algorithm's purported ability to generate human-like text across various domains. Yet, empirical evidence using incentivized tasks to assess human behavioral reactions to such algorithms is lacking. We conducted two experiments assessing behavioral reactions to the state-of-the-art Natural Language Generation algorithm GPT-2 (Ntotal = 830). Using the identical starting lines of human poems, GPT-2 produced samples of multiple algorithmically-generated poems. From these samples, either a random poem was chosen (Human-out-of-the-loop) or the best one was selected (Human-in-the-loop) and in turn matched with a human written poem. Taking part in a new incentivized version of the Turing Test, participants failed to reliably detect the algorithmically-generated poems in the human-in-the-loop treatment, yet succeeded in the Human-out-of-the-loop treatment. Further, the results reveal a general aversion towards algorithmic poetry, independent on whether participants were informed about the algorithmic origin of the poem (Transparency) or not (Opacity). We discuss what these results convey about the performance of NLG algorithms to produce human-like text and propose methodologies to study such learning algorithms in experimental settings.
The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies

Using 324 numerically modelled galaxy clusters, we investigate the radial and galaxy–halo alignment of dark matter subhaloes and satellite galaxies orbiting within and around them. We find that radial alignment depends on distance to the centre of the galaxy cluster but appears independent of the dynamical state of the central host cluster. Furthermore, we cannot find a relation between radial alignment of the halo or galaxy shape with its own mass. We report that backsplash galaxies, i.e. objects that have already passed through the cluster radius but are now located in the outskirts, show a stronger radial alignment than infalling objects. We further find that there exists a population of well radially aligned objects passing very close to the central cluster’s centre that were found to be on highly radial orbit.
Learning Representations using Spectral-Biased Random Walks on Graphs

Several state-of-the-art neural graph embedding methods are based on short random walks (stochastic processes) because of their ease of computation, simplicity in capturing complex local graph properties, scalability, and interpretibility. In this work, we are interested in studying how much a probabilistic bias in this stochastic process affects the quality of the nodes picked by the process. In particular, our biased walk, with a certain probability, favors movement towards nodes whose neighborhoods bear a structural resemblance to the current node’s neighborhood. We succinctly capture this neighborhood as a probability measure based on the spectrum of the node’s neighborhood subgraph represented as a normalized Laplacian matrix. We propose the use of a paragraph vector model with a novel Wasserstein regularization term. We empirically evaluate our approach against several state-of-the-art node embedding techniques on a wide variety of real-world datasets and demonstrate that our proposed method significantly improves upon existing methods on both link prediction and node classification tasks.
Anomaly Detection in Video Games

With the aim of designing automated tools that assist in the video game quality assurance process, we frame the problem of identifying bugs in video games as an anomaly detection (AD) problem. We develop State-State Siamese Networks (S3N) as an efficient deep metric learning approach to AD in this context and explore how it may be used as part of an automated testing tool. Finally, we show by empirical evaluation on a series of Atari games, that S3N is able to learn a meaningful embedding, and consequently is able to identify various common types of video game bugs.
Non-oscillating power spectra in loop quantum cosmology

We characterize in an analytical way the general conditions that a choice of vacuum state for the cosmological perturbations must satisfy to lead to a power spectrum with no scale-dependent oscillations over time. In particular, we pay special attention to the case of cosmological backgrounds governed by effective loop quantum cosmology and in which the Einsteinian branch after the bounce suffers a pre-inflationary period of decelerated expansion. This is the case more often studied in the literature because of the physical interest of the resulting predictions. In this context, we argue that non-oscillating power spectra are optimal to gain observational access to those regimes near the bounce where loop quantum cosmology effects are non-negligible. In addition, we show that non-oscillatory spectra can indeed be consistently obtained when the evolution of the perturbations is ruled by the hyperbolic equations derived in the hybrid loop quantization approach. Moreover, in the ultraviolet regime of short wavelength scales we prove that there exists a unique asymptotic expansion of the power spectrum that displays no scale-dependent oscillations over time. This expansion would pick out the natural Poincaré and Bunch–Davies vacua in Minkowski and de Sitter spacetimes, respectively, and provides an appealing candidate for the choice of a vacuum for the perturbations in loop quantum cosmology based on physical motivations.
Variability of OB stars from TESS southern Sectors 1–13 and high-resolution IACOB and OWN spectroscopy

Context. The lack of high-precision long-term continuous photometric data for large samples of stars has impeded the large-scale exploration of pulsational variability in the OB star regime. As a result, the candidates for in-depth asteroseismic modelling have remained limited to a few dozen dwarfs. The TESS nominal space mission has surveyed the southern sky, including parts of the galactic plane, yielding continuous data across at least 27 d for hundreds of OB stars. Aims. We aim to couple TESS data in the southern sky with ground-based spectroscopy to study the variability in two dimensions, mass and evolution. We focus mainly on the presence of coherent pulsation modes that may or may not be present in the predicted theoretical instability domains and unravel all frequency behaviour in the amplitude spectra of the TESS data. Methods. We compose a sample of 98 OB-type stars observed by TESS in Sectors 1–13 and with available multi-epoch, high-resolution spectroscopy gathered by the IACOB and OWN surveys. We present the short-cadence 2 min light curves of dozens of OB-type stars, which have one or more spectra in the IACOB or OWN database. Based on these light curves and their Lomb–Scargle periodograms, we performed variability classification and frequency analysis. We placed the stars in the spectroscopic Hertzsprung–Russell diagram to interpret the variability in an evolutionary context. Results. We deduce the diverse origins of the mmag-level variability found in all of the 98 OB stars in the TESS data. We find among the sample several new variable stars, including three hybrid pulsators, three eclipsing binaries, high frequency modes in a Be star, and potential heat-driven pulsations in two Oe stars. Conclusions. We identify stars for which future asteroseismic modelling is possible, provided mode identification is achieved. By comparing the position of the variables to theoretical instability strips, we discuss the current shortcomings in non-adiabatic pulsation theory and the distribution of pulsators in the upper Hertzsprung–Russell diagram.
The Morphology and Taxonomy of Leucochloridium (L.) variae Mclntosh (Digenea, Leucochloridiidae) from the Nearctic as Revealed by Light and Scanning Electron Microscopy

The morphology of the sporocyst and metacercarial stages of Leucochloridium (Leucochloridium) variae from Succinea ovalis in Nebraska, U.S.A. , as revealed by light microscopy is described, These results are compared with earlier Holarctic larval descriptions of the brown‐banded broodsac complex. The adult morphology as revealed by light and electron microscopical studies on experimentally reared adults from Larus canus and Taeniopygia guttata is described and compared with earlier information on this and other species described within the same species complex. No significant differences were found within the Nearctic, or between the Nearctic and Palaearctic material, which imply that L. variae McIntosh (and sensu Lewis), L. pricei McIntosh, the “Rensselaerville‐sporocyst” described by Ingram & Hewitt, L. fuscostriatum Robinson, L. perturbatum Pojmanska, L. subtilis Pojmanska, L. fuscum Rietschel, and Leucochloridium sp. described by Bakke, are considered conspecific, L. melospizae McIntosh sp. inquirenda. The tendencies for larval differences to be correlated with geographical subregions were judged to be no more than intraspecific variation within a brown‐banded sporocyst complex. Different characteristics of both larval and adult stages are described in more detail and discussed.
Soil and pasture responses to lime on dry hill country in central Hawke's Bay, New Zealand

Abstract Small plot trials were established with four combinations of aspect and slope (north‐easy, north‐steep, south‐easy, south‐steep) with initial soil pH 5.6, 5.4, 5.6, and 5.4, respectively) on hill country under low annual average rainfall (800 mm yr–1) near Waipawa in central Hawke's Bay. At each site, lime at 0, 0.5, 1.0, 2.0, 4.0, and 8.0 t ha–1 was applied once in November 2000 to increase soil pH to 5.4–5.6, 5.5–5.8, 5.7–5.9, 5.7–6.0, and 6.0–6.4, respectively for each rate of lime after 1 year. Soil exchangeable aluminium (Al) levels measured in November 2003 were above the critical level of 3 μg g–1, where root growth is restricted, on the north‐steep and south‐steep sites (4.48 and 5.23 μg g–1), just above on the south‐easy site (3.02 μg g–1) and below on the north‐easy site (1.45 μg g–1). At the north‐steep and south‐steep sites, soil Al was reduced below the critical level at rates of 0.5 and 1.0 t lime ha–1 and higher, respectively. There was no significant response in dry matter (DM) yield to lime measured at any site in Year 1 (December 2000‐November 2001), or for the north‐easy and north‐steep sites in Year 2 (December 2001‐November 2002) or Year 3 (December 2002‐November 2003). Lime had no significant effect on legume cover (19–61% in any one year) on the north‐easy site. Lime increased legume cover in years 2 and 3 (14–56%) on the north‐steep site. In Years 2 and 3, there was a significant DM yield response levelling off at 1.0 t lime ha–1 on both the south‐easy and south‐steep sites. On the south‐easy site, there was a significant response in legume cover to 0.5 t lime ha–1 and greater in Year 2, and 4.0t lime ha–1 and greater in Year 3 while on the south‐steep site there was a significant response in Year 2 to 1 t lime ha–1 and greater and in Year 3 to 2 t lime ha–1 and greater. Where a south aspect and easy slope favours legume growth in dry hill country, low rates of lime (1t ha–1) can result in a worthwhile pasture yield response, especially where soil Al levels are greater than 3 μg g–1.
MALE COMPETITION IN LARGE GROUPS OF WINTERING HUMPBACK WHALES

Fast moving groups containing three or more adult humpback whales are found in the winter on Silver Bank in the West Indies, and off Hawaii. Many of these groups have a definite structure: a central Nuclear Animal, with or without a calf, is surrounded by escorts who compete, sometimes violently, for proximity to the Nuclear Animal. This competition involves fluke thrashes, the blowing of bubblestreams, and physical contact, some of which appears designed to hurt an opponent: bleeding wounds are seen on the competing escorts. Escorts sometimes leave these groups and start singing, and singers sometimes stop to join large groups. The pattern of interactions strongly suggests that the escorts are males competing for access to a central female. Off Hawaii singers respond to such groups at ranges of up to approximately 7.5 km. On Silver Bank, Principal Escorts maintained a position of closest proximity to the Nuclear Animal for an average of 7.5 hours before replacement.
High-velocity interstellar absorption associated with the supernova remnant W28

We present an analysis of moderately high-resolution optical spectra obtained for the sightline to CD−23 13777, an O9 supergiant that probes high-velocity interstellar gas associated with the supernova remnant W28. Absorption components at both high positive and high negative velocity are seen in the interstellar Na i D and Ca ii H and K lines towards CD−23 13777. The high-velocity components exhibit low Na i/Ca ii ratios, suggesting efficient grain destruction by shock sputtering. High column densities of CH+, and high CH+/CH ratios, for the components seen at lower velocity may be indicative of enhanced turbulence in the clouds interacting with W28. The highest positive and negative velocities of the components seen in Na i and Ca ii absorption towards CD−23 13777 imply that the velocity of the blast wave associated with W28 is at least 150 km s−1, a value that is significantly higher than most previous estimates. The line of sight to CD−23 13777 passes very close to a well-known site of interaction between the supernova remnant and a molecular cloud to the north-east. The north-east molecular cloud exhibits broad molecular line emission, OH maser emission from numerous locations, and bright extended GeV and TeV γ-ray emission. The sightline to CD−23 13777 is thus a unique and valuable probe of the interaction between W28 and dense molecular gas in its environs. Future observations at ultraviolet and visible wavelengths will help to better constrain the abundances, kinematics, and physical conditions in the shocked and quiescent gas along this line of sight.
Sub-grid-scale effects in magnetised plasma turbulence

In the present paper, we use a coarse-graining approach to investigate the nonlinear redistribution of free energy in both position and scale space for weakly collisional magnetised plasma turbulence. For this purpose, we use high-resolution numerical simulations of gyrokinetic (GK) turbulence that span the proton–electron range of scales, in a straight magnetic guide field geometry. Accounting for the averaged effect of the particles’ fast gyro-motion on the slow plasma fluctuations, the GK approximation captures the dominant energy redistribution mechanisms in strongly magnetised plasma turbulence. Here, the GK system is coarse grained with respect to a cut-off scale, separating in real space the contributions to the nonlinear interactions from the coarse-grid scales and the sub-grid scales (SGS). We concentrate on the analysis of nonlinear SGS effects. Not only does this allow us to investigate the flux of free energy across the scales, but also to now analyse its spatial density. We find that the net value of scale flux is an order of magnitude smaller than both the positive and negative flux density contributions. The dependence of the results on the filter type is also analysed. Moreover, we investigate the advection of energy in position space. This rather novel approach for GK turbulence can help in the development of SGS models that account for advective unstable structures for space and fusion plasmas, and with the analysis of the turbulent transport saturation.
Embeddings-Based Clustering for Target Specific Stances: The Case of a Polarized Turkey

On June 24, 2018, Turkey conducted a highly consequential election in which the Turkish people elected their president and parliament in the first election under a new presidential system. During the election period, the Turkish people extensively shared their political opinions on Twitter. One aspect of polarization among the electorate was support for or opposition to the reelection of Recep Tayyip Erdoğan. In this paper, we present an unsupervised method for target-specific stance detection in a polarized setting, specifically Turkish politics, achieving 90% precision in identifying user stances, while maintaining more than 80% recall. The method involves representing users in an embedding space using Google's Convolutional Neural Network (CNN) based multilingual universal sentence encoder. The representations are then projected onto a lower dimensional space in a manner that reflects similarities and are consequently clustered. We show the effectiveness of our method in properly clustering users of divergent groups across multiple targets that include political figures, different groups, and parties. We perform our analysis on a large dataset of 108M Turkish election-related tweets along with the timeline tweets of 168k Turkish users, who authored 213M tweets. Given the resultant user stances, we are able to observe correlations between topics and compute topic polarization.
Movement of two grassland butterflies in the same habitat network: the role of adult resources and size of the study area

Abstract. 1. Movement patterns of two butterfly species (meadow brown Maniola jurtina L. and scarce copper Lycaenae virgaureae L.) were studied in a 172 ha area within a landscape with a high percentage of suitable habitats for mark–release–recapture experiments.
Active Speakers in Context

Current methods for active speaker detection focus on modeling audiovisual information from a single speaker. This strategy can be adequate for addressing single-speaker scenarios, but it prevents accurate detection when the task is to identify who of many candidate speakers are talking. This paper introduces the Active Speaker Context, a novel representation that models relationships between multiple speakers over long time horizons. Our new model learns pairwise and temporal relations from a structured ensemble of audiovisual observations. Our experiments show that a structured feature ensemble already beneï¬ts active speaker detection performance. We also ï¬nd that the proposed Active Speaker Context improves the state-of-the-art on the AVA-ActiveSpeaker dataset achieving an mAP of 87.1%. Moreover, ablation studies verify that this result is a direct consequence of our long-term multi-speaker analysis.
Classifying Suspicious Content in Tor Darknet

One of the tasks of law enforcement agencies is to find evidence of criminal activity in the Darknet. However, visiting thousands of domains to locate visual information containing illegal acts manually requires a considerable amount of time and resources. Furthermore, the background of the images can pose a challenge when performing classification. To solve this problem, in this paper, we explore the automatic classification Tor Darknet images using Semantic Attention Keypoint Filtering, a strategy that filters non-significant features at a pixel level that do not belong to the object of interest, by combining saliency maps with Bag of Visual Words (BoVW). We evaluated SAKF on a custom Tor image dataset against CNN features: MobileNet v1 and Resnet50, and BoVW using dense SIFT descriptors, achieving a result of 87.98% accuracy and outperforming all other approaches.
The effect of N-terminal truncation on double-dimer assembly of goose δ-crystallin

δ-Crystallin is a soluble structural protein in avian eye lenses that confers special refractive properties. In the presence of GdmCl (guanidinium chloride), tetrameric δ-crystallin undergoes dissociation via a dimeric state to a monomeric molten globule intermediate state. The latter are denatured at higher GdmCl concentrations in a multi-state manner. In the present study, the X-ray structure of goose δ-crystallin was determined to 2.8 A (1 A=0.1 nm). In this structure the first 25 N-terminal residues interact with a hydrophobic cavity in a neighbouring molecule, stabilizing the quaternary structure of this protein. When these 25 residues were deleted this did not produce any gross structural changes, as judged by CD analysis, but slightly altered tryptophan fluorescence and ANS (8-anilino-1-naphthalenesulphonic acid) spectra. The dimeric form was significantly identified as judged by sedimentation velocity and nondenaturing gradient gel electrophoresis. This mutant had increased sensitivity to temperature denaturation and GdmCl concentrations of 0.3–1.0 M. This protein was destabilized about 3.3 kcal/mol (1 kcal=4.184 kJ) due to N-terminal truncation. After incubation at 37 °C N-terminal truncated proteins were prone to aggregation, suggesting the presence of the unstable dimeric conformation. An important role for the N-terminus in dimer assembly of goose δ-crystallin is proposed.
Global Dysregulation of miRNAs via Dicer Deficiency in Atherosclerosis

Molecular and phenotypic changes of vascular smooth muscle cells are key components of atherogenesis. miRNAs control, at least in part, this phenotypic transition via desuppression of pro-inflammatory factors. Although specific miRNAs have been implicated in atherosclerosis, a mechanism for their dysregulation remains unknown. Global expression profiling of miRNAs via microarray in healthy versus atherosclerotic murine aorta displayed an overall 30% reduction of miRNA abundance in atherosclerosis. We observed a decrease in Dicer, a key enzyme for miRNA biogenesis, in atherosclerosis. In accordance with this finding, we observed an accumulation in the Dicer substrate precursormiRNAs despite a decrease in mature levels. Surprisingly, we found Dicer expression in healthy mice to be basally lower in atheroprone areas of the vasculature. Therefore, we propose that global regulation of miRNAs via Dicer deficiency is an important facet of atherogenesis, and desuppression of atherogenic transcription factors such as Runx2 via downregulation of miR-133 in disease.