Africa
Robust Causal Directionality Inference in Quantum Inference under MNAR Observation and High-Dimensional Noise
In quantum mechanics, observation actively shapes the system, paralleling the statistical notion of Missing Not At Random (MNAR). This study introduces a unified framework for \textbf{robust causal directionality inference} in quantum engineering, determining whether relations are system$\to$observation, observation$\to$system, or bidirectional. The method integrates CVAE-based latent constraints, MNAR-aware selection models, GEE-stabilized regression, penalized empirical likelihood, and Bayesian optimization. It jointly addresses quantum and classical noise while uncovering causal directionality, with theoretical guarantees for double robustness, perturbation stability, and oracle inequalities. Simulation and real-data analyses (TCGA gene expression, proteomics) show that the proposed MNAR-stabilized CVAE+GEE+AIPW+PEL framework achieves lower bias and variance, near-nominal coverage, and superior quantum-specific diagnostics. This establishes robust causal directionality inference as a key methodological advance for reliable quantum engineering.
One Permutation Is All You Need: Fast, Reliable Variable Importance and Model Stress-Testing
Reliable estimation of feature contributions in machine learning models is essential for trust, transparency and regulatory compliance, especially when models are proprietary or otherwise operate as black boxes. While permutation-based methods are a standard tool for this task, classical implementations rely on repeated random permutations, introducing computational overhead and stochastic instability. In this paper, we show that by replacing multiple random permutations with a single, deterministic, and optimal permutation, we achieve a method that retains the core principles of permutation-based importance while being non-random, faster, and more stable. We validate this approach across nearly 200 scenarios, including real-world household finance and credit risk applications, demonstrating improved bias-variance tradeoffs and accuracy in challenging regimes such as small sample sizes, high dimensionality, and low signal-to-noise ratios. Finally, we introduce Systemic Variable Importance, a natural extension designed for model stress-testing that explicitly accounts for feature correlations. This framework provides a transparent way to quantify how shocks or perturbations propagate through correlated inputs, revealing dependencies that standard variable importance measures miss. Two real-world case studies demonstrate how this metric can be used to audit models for hidden reliance on protected attributes (e.g., gender or race), enabling regulators and practitioners to assess fairness and systemic risk in a principled and computationally efficient manner.
Lifelong Neural Predictive Coding: Learning Cumulatively Online without Forgetting
In lifelong learning systems based on artificial neural networks, one of the biggest obstacles is the inability to retain old knowledge as new information is encountered. This phenomenon is known as catastrophic forgetting. In this paper, we propose a new kind of connectionist architecture, the Sequential Neural Coding Network, that is robust to forgetting when learning from streams of data points and, unlike networks of today, does not learn via the popular back-propagation of errors. Grounded in the neurocognitive theory of predictive coding, our model adapts its synapses in a biologically-plausible fashion while another neural system learns to direct and control this cortex-like structure, mimicking some of the task-executive control functionality of the basal ganglia. In our experiments, we demonstrate that our self-organizing system experiences significantly less forgetting compared to standard neural models, outperforming a swath of previously proposed methods, including rehearsal/data buffer-based methods, on both standard (SplitMNIST, Split Fashion MNIST, etc.) and custom benchmarks even though it is trained in a stream-like fashion. Our work offers evidence that emulating mechanisms in real neuronal systems, e.g., local learning, lateral competition, can yield new directions and possibilities for tackling the grand challenge of lifelong machine learning.
Smoothing the Landscape Boosts the Signal for SGD: Optimal Sample Complexity for Learning Single Index Models
We focus on the task of learning a single index model $\sigma(w^\star \cdot x)$ with respect to the isotropic Gaussian distribution in $d$ dimensions. Prior work has shown that the sample complexity of learning $w^\star$ is governed by the information exponent $k^\star$ of the link function $\sigma$, which is defined as the index of the first nonzero Hermite coefficient of $\sigma$. Ben Arous et al. (2021) showed that $n \gtrsim d^{k^\star-1}$ samples suffice for learning $w^\star$ and that this is tight for online SGD. However, the CSQ lower bound for gradient based methods only shows that $n \gtrsim d^{k^\star/2}$ samples are necessary. In this work, we close the gap between the upper and lower bounds by showing that online SGD on a smoothed loss learns $w^\star$ with $n \gtrsim d^{k^\star/2}$ samples. We also draw connections to statistical analyses of tensor PCA and to the implicit regularization effects of minibatch SGD on empirical losses.
Three killed after Russia launches 'massive' attack across Ukraine
Three killed after Russia launches'massive' attack across Ukraine Russia carried out a massive overnight attack on several Ukrainian cities, President Volodymyr Zelensky has said, a day after he warned of strikes over the Christmas period. At least three people were killed, according to Ukrainian officials, including a four-year-old child, while energy infrastructure was also targeted, leaving several regions without power. Russia launched 635 drones and 38 missiles, Ukraine's air force said, adding that 621 of them were downed. Zelensky said people simply want to be with their families, at home, and safe in the run-up to Christmas, and said the strikes sent an extremely clear signal about Russia's priorities despite ongoing peace talks. He added that Russian President Vladimir Putin still cannot accept that he must stop killing.
How Christian Leaders Are Challenging the AI Boom
Pope Leo XIV made his first address to the College of Cardinals on May 10, 2025 in Vatican City, and touched upon the rise of artificial intelligence. Pope Leo XIV made his first address to the College of Cardinals on May 10, 2025 in Vatican City, and touched upon the rise of artificial intelligence. As technologists race to accelerate AI's progress with minimal guardrails, they are being met with increasing resistance from a powerful global contingent: Christian leaders and their congregations. Christians are not a monolith by any means. But this year, Christian leaders across sects--including Catholics, Evangelicals, and Baptists--sounded the alarm on AI's potential impact on family, human relationships, labor, and the church itself.
Watch: AI app apologises over false crime alerts across US
A company behind an AI-powered app called CrimeRadar has apologised for the distress caused by false crime alerts issued to local US communities after a BBC Verify investigation. CrimeRadar uses artificial intelligence to monitor openly available police radio communications, automatically generating a transcript and then producing crime alerts for users across the US. BBC Verify has found multiple instances from Florida to Oregon of CrimeRadar sending misleading and inaccurate alerts about serious crime to local residents - as Thomas Copeland explains. The barge that wrecked in 1918, famous for a dramatic rescue, is now shifting closer to the falls as recent movements carry it further from its original resting spot. House Speaker Mike Johnson, Hakeem Jeffries and Chuck Schumer participated in the annual ceremony that commemorates the eight days of Hanukkah.
The showers and baths keeping data centre tech cool
They work 24/7 at high speeds and get searingly hot - but data centre computer chips get plenty of pampering. Some of them basically live at the spa. We'll have fluid that comes up and [then] shower down, or trickle down, onto a component, says Jonathan Ballon, chief executive at liquid cooling firm Iceotope. Some things will get sprayed. In other cases, the industrious gizmos recline in circulating baths of fluid, which ferries away the heat they generate, enabling them to function at very high speeds, known as overclocking.
Testing for latent structure via the Wilcoxon--Wigner random matrix of normalized rank statistics
Liao, Jonquil Z., Cape, Joshua
This paper considers the problem of testing for latent structure in large symmetric data matrices. The goal here is to develop statistically principled methodology that is flexible in its applicability, computationally efficient, and insensitive to extreme data variation, thereby overcoming limitations facing existing approaches. To do so, we introduce and systematically study certain symmetric matrices, called Wilcoxon--Wigner random matrices, whose entries are normalized rank statistics derived from an underlying independent and identically distributed sample of absolutely continuous random variables. These matrices naturally arise as the matricization of one-sample problems in statistics and conceptually lie at the interface of nonparametrics, multivariate analysis, and data reduction. Among our results, we establish that the leading eigenvalue and corresponding eigenvector of Wilcoxon--Wigner random matrices admit asymptotically Gaussian fluctuations with explicit centering and scaling terms. These asymptotic results enable rigorous parameter-free and distribution-free spectral methodology for addressing two hypothesis testing problems, namely community detection and principal submatrix detection. Numerical examples illustrate the performance of the proposed approach. Throughout, our findings are juxtaposed with existing results based on the spectral properties of independent entry symmetric random matrices in signal-plus-noise data settings.
Unsupervised Feature Selection via Robust Autoencoder and Adaptive Graph Learning
Yu, Feng, Mazumder, MD Saifur Rahman, Su, Ying, Velasco, Oscar Contreras
Effective feature selection is essential for high-dimensional data analysis and machine learning. Unsupervised feature selection (UFS) aims to simultaneously cluster data and identify the most discriminative features. Most existing UFS methods linearly project features into a pseudo-label space for clustering, but they suffer from two critical limitations: (1) an oversimplified linear mapping that fails to capture complex feature relationships, and (2) an assumption of uniform cluster distributions, ignoring outliers prevalent in real-world data. To address these issues, we propose the Robust Autoencoder-based Unsupervised Feature Selection (RAEUFS) model, which leverages a deep autoencoder to learn nonlinear feature representations while inherently improving robustness to outliers. We further develop an efficient optimization algorithm for RAEUFS. Extensive experiments demonstrate that our method outperforms state-of-the-art UFS approaches in both clean and outlier-contaminated data settings.