Negative / Null Result ReportOpen accessMathematics
Ziling Ma, Ángel López Oriona, Hernando Ombao et al. · 2026 · arXiv
We study adaptive pooling under predictive heterogeneity in high-dimensional multivariate time series forecasting, where global models improve statistical efficiency but may fail to capture heterogeneous predictive structure, while naive specialization can induce negative transfer. We formulate adaptive pooling as a statistical decision problem and propose a validation-driven framework that determines when and how specialization should be applied. Rather than grouping series based on representation similarity, we define partitions through out-of-sample predictive performance, thereby aligning
Negative / Null Result ReportOpen accessMathematics
Rong Chen, Simone Giannerini, Greta Goracci et al. · 2025 · arXiv
We develop an estimation methodology for a factor model for high-dimensional matrix-valued time series, where common stochastic trends and common stationary factors can be present. We study, in particular, the estimation of (row and column) loading spaces, of the common stochastic trends and of the common stationary factors, and the row and column ranks thereof. In a set of (negative) preliminary results, we show that a projection-based technique fails to improve the rates of convergence compared to a "flattened" estimation technique which does not take into account the matrix nature of the da
Negative / Null Result ReportOpen accessComputer Science
Lennart Meincke, Ethan Mollick, Lilach Mollick et al. · 2025 · arXiv
This is the third in a series of short reports that seek to help business, education, and policy leaders understand the technical details of working with AI through rigorous testing. In this report, we investigate two commonly held prompting beliefs: a) offering to tip the AI model and b) threatening the AI model. Tipping was a commonly shared tactic for improving AI performance and threats have been endorsed by Google Founder Sergey Brin (All-In, May 2025, 8:20) who observed that 'models tend to do better if you threaten them,' a claim we subject to empirical testing here. We evaluate model p
Negative / Null Result ReportOpen accessComputer Science
Hongsin Lee, Hye Won Chung · 2026 · arXiv
Adversarial Distillation aims to enhance student robustness by guiding the student with a robust teacher's soft labels within the min-max adversarial training framework, yet its success is notoriously inconsistent: a more robust teacher often fails to improve, or even harms, the student's robust generalization. In this paper, we identify a key mechanism of this teacher dependency: the misalignment between the teacher's supervisory confidence and the student's representational limitations on a consistent subset of training data -- the Robustly Unlearnable Set. We present a theoretical framework
Negative / Null Result ReportOpen accessComputer Science
Masahito Hayashi · 2025 · arXiv
We consider estimation of unknown unitary operation when the set of possible unitary operations is given by a projective unitary representation of a compact group. We show that neither indefinite causal order strategy nor adaptive strategy improves the performance of this estimation when error function satisfies group covariance. That is, the optimal parallel strategy gives the optimal performance even under indefinite causal order strategy and adaptive strategy. To study this problem, we newly introduce the concept of generalized positive operator valued measure (GPOVM), and its convariance c
Negative / Null Result ReportOpen accessEngineering
Kwon Byung-Ki, Oh Hyun-Bin, Kim Jun-Seong et al. · 2023 · arXiv
Video motion magnification amplifies invisible small motions to be perceptible, which provides humans with a spatially dense and holistic understanding of small motions in the scene of interest. This is based on the premise that magnifying small motions enhances the legibility of motions. In the real world, however, vibrating objects often possess convoluted systems that have complex natural frequencies, modes, and directions. Existing motion magnification often fails to improve legibility since the intricate motions still retain complex characteristics even after being magnified, which may di
Negative / Null Result ReportOpen accessComputer Science
Xirui Li, Ming Li, Tianyi Zhou · 2026 · arXiv
Reinforcement learning (RL) with verifiable rewards has become a standard post-training stage for boosting visual reasoning in vision-language models, yet it remains unclear what capabilities RL actually improves compared with supervised fine-tuning as cold-start initialization (IN). End-to-end benchmark gains conflate multiple factors, making it difficult to attribute improvements to specific skills. To bridge the gap, we propose a Frankenstein-style analysis framework including: (i) functional localization via causal probing; (ii) update characterization via parameter comparison; and (iii) t
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Mohammad Hassan Shakil, Arne Johan Pollestad, Khine Kyaw et al. · 2025 · arXiv
With European Union initiatives mandating gender quotas on corporate boards, a key question arises: Is greater board gender diversity (BGD) associated with better emissions performance (EP)? To answer this question, we examine the influence of BGD on EP across a sample of European firms from 2016 to 2022. Using panel regressions, advanced machine learning algorithms, and explainable AI, we reveal a non-linear relationship. Specifically, EP improves with BGD up to an optimal level of approximately 35 %, beyond which further increases in BGD yield no additional improvement in EP. A minimum BGD t
Negative / Null Result ReportMedicine
Fuentes-Expósito, Frid, Muñoz-Mateu et al. · 2026 · JCO clinical cancer informatics
We evaluated whether offering access to a multicomponent mHealth app improves quality of life (QoL) and psychosocial outcomes among breast cancer survivors under pragmatic, nonprescriptive conditions. In this single-center, randomized,…
View details →DOI: 10.1200/cci-26-00025 Negative / Null Result ReportMedicine
Yang, Zhu, Chen et al. · 2026 · Frontiers in neuroscience
To observe the therapeutic effects of deep transcranial magnetic stimulation (dTMS) and repetitive transcranial magnetic stimulation (rTMS) on upper and lower limb motor dysfunction in patients with basal ganglia infarction, and to…
View details →DOI: 10.3389/fnins.2026.1870537 Negative / Null Result Report
Rebecca L Rivera, Melissa K Maulding, Angela R Abbott et al. · 2016 · The FASEB Journal
Objective To determine the relationship of rural and urban county household status to long‐term food security among households with children in Indiana after a Supplemental Nutrition Assistance Program‐Education (SNAP‐Ed) intervention.…
View details →DOI: 10.1096/fasebj.30.1_supplement.674.26 Negative / Null Result ReportOpen accessComputer Science
Roland S. Zimmermann, Thomas Klein, Wieland Brendel · 2023 · arXiv
In light of the recent widespread adoption of AI systems, understanding the internal information processing of neural networks has become increasingly critical. Most recently, machine vision has seen remarkable progress by scaling neural networks to unprecedented levels in dataset and model size. We here ask whether this extraordinary increase in scale also positively impacts the field of mechanistic interpretability. In other words, has our understanding of the inner workings of scaled neural networks improved as well? We use a psychophysical paradigm to quantify one form of mechanistic inter
Negative / Null Result Report
M Erickson, N Tomassoni, R Sun et al. · 2026 · Europace
Abstract Background/Introduction Bachmann bundle pacing (BBP) has emerged as a favorable alternative to traditional right atrial appendage (RAA) pacing, offering benefits such as reduced atrial fibrillation and improved diastolic function.…
View details →DOI: 10.1093/europace/euag105.733 Negative / Null Result ReportMedicine
Du, Zhang, Xu et al. · 2026 · Scientific reports
To evaluate the remediation strategies for newly reclaimed, heavily salinized farmland in Xinjiang province, China, a three-year field experiment was conducted comparing different treatments, such as agricultural improvement measures…
View details →DOI: 10.1038/s41598-026-57986-1 Negative / Null Result ReportOpen accessPhysics
B. Megyeri, A. Lampis, G. Harvie et al. · 2017 · arXiv
We discuss the prospects for enhancing absorption and scattering of light from a weakly coupled atom in a high-finesse optical cavity by adding a medium with large, positive group index of refraction. The slow-light effect is known to narrow the cavity transmission spectrum and increase the photon lifetime, but the quality factor of the cavity may not be increased in a metrologically useful sense. Specifically, detection of the weakly coupled atom through either cavity ringdown measurements or the Purcell effect fails to improve with the addition of material slow light. A single-atom model of
Negative / Null Result ReportMedicine
Tasgaonkar, Rathi, Agrawal et al. · 2026 · International journal of clinical pediatric dentistry
Preserving primary teeth with crowns is vital in pediatric dentistry, especially for those compromised by dental caries, previous treatments, or malformations. To address the limitations of traditional esthetic crowns, Bioflx crowns have…
View details →DOI: 10.5005/jp-journals-10005-3480 Negative / Null Result Report
Muhammad Dawood Mian, Saadullah Jan Khan, Rehana Rani et al. · 2026 · Access Microbiology
Rapid and reliable identification of bacteria is essential in clinical and environmental microbiology. Gram staining remains a widely used method for preliminary classification; however, it may require additional steps and can be difficult…
View details →DOI: 10.1099/acmi.0.000965.v3 Negative / Null Result ReportMedicine
Lahaye, Haegdorens, Franck et al. · 2026 · European geriatric medicine
To evaluate the effectiveness of a structured, team-delivered intervention based on cognitive behavioural therapy for insomnia (CBT-I) on sleep and related outcomes in nursing home residents. A cluster randomised controlled trial with…
View details →DOI: 10.1007/s41999-026-01519-6 Negative / Null Result Report
Mary Cushman, Suzanne E Judd, Virginia J Howard et al. · 2011 · Circulation
Background. The AHA 2020 Goal includes improving cardiovascular health, defined using a metric consisting of 7 health factors, Life's Simple 7. A central concept of the goal is that small improvements in behavior / lifestyle factors at the…
View details →DOI: 10.1161/circ.124.suppl_21.a17917 Negative / Null Result ReportMedicine
Abelovska, Malinova, Sucha et al. · 2026 · Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology
This pilot study evaluated "Your Health Belongs to You," a six-week group intervention combining psychotherapy and exercise to improve quality of life, emotional health, and symptom management in individuals with Multiple Sclerosis (MS),…
View details →DOI: 10.1007/s10072-026-09130-0 Negative / Null Result ReportOpen accessComputer Science
Thomas Vogel, Chinh Tran, Lars Grunske · 2019 · arXiv
In search-based software engineering we often use popular heuristics with default configurations, which typically lead to suboptimal results, or we perform experiments to identify configurations on a trial-and-error basis, which may lead to better results for a specific problem. To obtain better results while avoiding trial-and-error experiments, a fitness landscape analysis is helpful in understanding the search problem, and making an informed decision about the heuristics. In this paper, we investigate the search problem of test suite generation for mobile applications (apps) using SAPIENZ w
Negative / Null Result ReportMedicine
Wang, Li, Zhang et al. · 2026 · Child development
This study examines how center-based parenting interventions aimed at improving early child development in rural China affect the mental health of caregivers. Data from an analytic sample of 615 caregiver-child dyads (children aged 6 to 24…
View details →DOI: 10.1093/chidev/aacag099 Negative / Null Result ReportOpen accessComputer Science
Shufan Wang, Yixiao Song, Andrew Drozdov et al. · 2023 · arXiv
In this paper, we study the generation quality of interpolation-based retrieval-augmented language models (LMs). These methods, best exemplified by the KNN-LM, interpolate the LM's predicted distribution of the next word with a distribution formed from the most relevant retrievals for a given prefix. While the KNN-LM and related methods yield impressive decreases in perplexity, we discover that they do not exhibit corresponding improvements in open-ended generation quality, as measured by both automatic evaluation metrics (e.g., MAUVE) and human evaluations. Digging deeper, we find that interp
Negative / Null Result ReportMedicine
Partlova, Comley, Haigh et al. · 2026 · Experimental neurology
Spinal muscular atrophy (SMA) is characterized by motor neuron loss and neuromuscular junction (NMJ) pathology. Although SMN-upregulating therapies such as Nusinersen markedly improve survival and motor function for many patients,…
View details →DOI: 10.1016/j.expneurol.2026.115898 Negative / Null Result ReportMedicine
Shalamov, Cromwell, Guha · 2026 · AJP reports
Background: Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder that causes alveolar hypoventilation because of impaired chemoreceptor response to hypercapnia and hypoxia occurring due to a dysfunctional central…
View details →DOI: 10.1055/a-2873-6868 Negative / Null Result ReportMedicine
Su, Huang, Wang · 2026 · SLAS technology
The accumulation of pathological bronchial secretions compromises ventilation and oxygenation in critically ill patients and may lead to atelectasis or secondary infection in severe cases, making timely identification and removal of…
View details →DOI: 10.1016/j.slast.2026.100443 Negative / Null Result Report
Ainun Oktavia Sari, Rahayu Sulistyowati, Ita Prihantika · 2020 · Administrativa: Jurnal Birokrasi, Kebijakan dan Pelayanan Publik
The Conditional Cash Transfer (CCT) is a conditional social cash transfer program that provides assistance to Very Poor Households (RTSM) appointed as participants in the Conditional Cash Transfer program which is related to improving the…
View details →DOI: 10.23960/administrativa.v2i3.51 Negative / Null Result ReportOpen accessComputer Science
Niek Beckers, Edwin van Asseldonk, Herman van der Kooij · 2020 · arXiv
Haptic interaction between two humans, for example, a physiotherapist assisting a patient regaining the ability to grasp a cup, likely facilitates motor skill acquisition. Haptic human-human interaction has been shown to enhance individual performance improvement in a tracking task with a visuomotor rotation perturbation. These results are remarkable given that haptically assisting or guiding an individual rarely benefits their individual improvement when the assistance is removed. We, therefore, replicated a study that reported that haptic interaction between humans was beneficial for individ
Negative / Null Result ReportOpen accessComputer Science
Runtian Zhai, Chen Dan, Zico Kolter et al. · 2022 · arXiv
Empirical risk minimization (ERM) is known in practice to be non-robust to distributional shift where the training and the test distributions are different. A suite of approaches, such as importance weighting, and variants of distributionally robust optimization (DRO), have been proposed to solve this problem. But a line of recent work has empirically shown that these approaches do not significantly improve over ERM in real applications with distribution shift. The goal of this work is to obtain a comprehensive theoretical understanding of this intriguing phenomenon. We first posit the class o
Negative / Null Result ReportOpen accessMathematics
Mark Rubin · 2020 · arXiv
Preregistration entails researchers registering their planned research hypotheses, methods, and analyses in a time-stamped document before they undertake their data collection and analyses. This document is then made available with the published research report to allow readers to identify discrepancies between what the researchers originally planned to do and what they actually ended up doing. This historical transparency is supposed to facilitate judgments about the credibility of the research findings. The present article provides a critical review of 17 of the reasons behind this argument.
