Wasserstein Distance-based Graph Contrastive Learning for Recommendation

Graph contrastive learning (GCL) is able to learn augmentation-invariant representations from raw data and reduce the dependence on labeled data. In the field of recommendation systems, traditional GCL models become a potential solution to insufficient supervision signals by augmenting the user-item interaction graph and optimizing InfoNCE loss to learn user and item representations. However, existing GCL-based recommendation models are limited by dimensional collapse, causing the sub-optimal performance of recommendation models. To tackle this problem, we propose a Wasserstein Distance-based Graph Contrastive Learning model, namely WGCL. Specifically, we integrate the Wasserstein loss into contrastive learning-based recommendation models to align the user/item representations distribution with the isotropic Gaussian distribution, which makes the real distribution of representations more uniform, thereby alleviating dimensional collapse. In fact, Wasserstein loss measures the distinction between the real distribution of entities’ representations and the desired distribution of representations by computing the covariance of representations learned from the augmented views. As a result, Wasserstein distance metric not only enables the representations more uniformly distributed on the hypersphere, but also better preserves the original semantic information of entities. Extensive experiments conducted on three widely used datasets demonstrate that WGCL outperforms traditional recommendation models. Our code is released at https://github.com/Sodapease/WGC

Male nuptial ornamentation of invasive guppies (<i>Poecilia reticulata</i>) responds to water pollution via phenotypic plasticity and microevolutionary change

Invasive alien species are increasingly replacing native species, with human habitat alterations often favoring invasive taxa. The Brazilian Rio Uberabinha, for instance, was found to harbor more invasive guppies (Poecilia reticulata) at polluted than non-polluted sites. Studies in other regions reported numeric frequencies of certain nuptial color ornaments of guppy males to either in- or decrease along pollution gradients, which has been interpreted to largely reflect population differences of (heritable) male ornamentation patterns. But could plasticity play an additional, or possibly even greater role in creating phenotypic variation of nuptial ornaments? Here, we examined male guppies along a gradient of diffuse water pollution of domestic and industrial origins in the Rio Uberabinha and quantified not only the number of ornaments (and percentage body cover), but also population differences in color intensity (total coloration, ΔE). The latter metric likely reflects plasticity during ornament development, e.g., through general challenges to physiological homeostasis or suppression of male ornamentation following xenestrogen exposure. We found numbers and % body cover of violet ornaments to increase as water pollution intensified. Black, orange, blue and violet ornaments responded to additional components of environmental variation that were not the focus of our present study (e.g., stream velocity, dissolved oxygen). Moreover, we found systematic variation of ΔE along the examined pollution gradient in the case of white/iridescent ornaments, with fish becoming more brightly colored at more polluted sites, possibly related to an alteration of uric acid and guanine biosynthesis and/or accumulation. White/iridescent and green ornaments also responded to additional components of environmental variation. Hence, it appears that both, plasticity and evolutionary changes, jointly create phenotypic diversification of different ornament types. Our study provides novel insights into the manifold ways by which man-made habitat alterations can alter evolutionary trajectories (here: components of sexual selection) of the populations exposed to them

The Gestural Potential of Music: Identifying Musical Meaning, Engagement and Immersion in Video Game Music

Videogame music engages players, summoning us into virtual worlds and soundscapes, encouraging us to adhere to the ludic parameters and play. This article establishes a new gestural analytical framework tailored to the playful audiovisual individualities of videogame design to reveal how players might become engaged in games. Case studies examined here include Super Mario World (1990) and Super Metroid (1994). I present a new analytical theory, graphically mapping gestures to determine the ways in which videogame music can successfully engage players to feel part of the ludo-narrative journey through a concept I term the ‘gestural potential’ of music

Hydroxyl (OH) radical oxidation of surfactant films formed from woodland aerosol particulate material at the air-water interface

Neutron reflectometry was used to examine the reaction of gas-phase hydroxyl radicals with thin surfactant films at the air–water interface. The films comprised insoluble material extracted from aerosol particulate matter collected from the atmosphere of a broadleaf woodland; sampled above and below the canopy across spring, summer, and winter. The measurements presented here act as a proxy for oxidation reactions at the air–water interface of broadleaf woodland atmospheric aqueous aerosols. The material extracted from the woodland atmosphere formed stable surfactant-like thin films at the air–water interface, with maximum thicknesses of 30 Å and neutron scattering length densities between 0.1 × 10−6 Å−2 and 2.5 × 10−6 Å−2. Oxidation by hydroxyl radicals reduced the amount of interfacial material, leaving an oxidation-resistant fraction of 20%–60% of the original film. The values of the surface reaction coefficients, determined by KM-SUB, for the reaction of hydroxyl radicals with woodland films were approximately 10−7 cm2 s−1. Film half-lives were estimated to be 1—2 h in typical day-time hydroxyl radical concentrations and 2 days–1 week in night-time concentrations. Thus, organic material extracted from temperate, broadleaf woodland aerosol can form thin, stable surfactant films at the air–water interface that can be partially removed by the gas-phase hydroxyl radical at a significant enough rate to warrant inclusion in atmospheric models

A Novel Lift Adjustment Methodology for Improving Association Rule Interpretation

Association rules can offer a human-interpretable insight extracted from data. The lift measures used for evaluating association rules in classical Association Rule Mining (ARM) contexts are mainly based on traditional and well-known ones but suffer from interpretation inadequacy when dealing with skewed distributions or low support. This study introduces a new lift adjustment approach with four methods to overcome traditional lift measures and identify the best rules in association rule mining. More concretely, our main objective is to improve the interpretability of association rules to make them more practically relevant for decision-making. We propose an approach incorporating four novel lift adjustment methods (smoothed, weighted, log, and threshold-adjusted lift) to achieve this. We introduce a flexible, dynamic approach combined with four new lift adjustment methods: smoothed, weighted, logarithm, and threshold-adjusted lift. Each technique addresses specific limitations of the traditional lift measure and better captures the reliable representation of item associations by exaggerating stronger relationships or smoothing weaker ones. The proposed methods applied context-aware rule evaluation and adjustment based on measures of relative significance (e.g., Jaccard similarity). The experimental results involving real-world data and synthetic datasets reveal new methods’ effectiveness and robustness in understanding the strengths of association rules and provide a comprehensive view that considers item importance. We evaluate the performance stability of our proposed methods using statistical analysis, including ANOVA, chi-squared, t-tests, and effect size metrics

A Problem with the Current Methodology for Comparing Search Algorithms and a Proposed Solution

This paper explores how incompletely described tie-break policies can invalidate the experimental results reported in papers on optimal bidirectional heuristic search (BiHS). Experiments usually use a single implementation of an algorithm with its specific tie-break policy. When the tie-breaks are insufficiently described, we show that the results can be irreproducible, vary dramatically under different implementations, and lead to misleading assessments of an algorithm’s performance. To ensure reproducible and representative results, papers should either provide a description of the algorithm’s implementation, i.e., the complete tie-break policy, or alternatively, give results as a summary statistic representative of all possible tie-break implementations. We developed a software tool for this purpose