Task Arithmetic in the Tangent Space: Improved Editing of Pre-Trained Models

Task arithmetic has recently emerged as a cost-effective and scalable approach to edit pre-trained models directly in weight space: By adding the fine-tuned weights of different tasks, the model's performance can be improved on these tasks, while negating them leads to task forgetting. Yet, our understanding of the effectiveness of task arithmetic and its underlying principles remains limited. We present a comprehensive study of task arithmetic in vision-language models and show that weight disentanglement is the crucial factor that makes it effective. This property arises during pre-training and manifests when distinct directions in weight space govern separate, localized regions in function space associated with the tasks. Notably, we show that fine-tuning models in their tangent space by linearizing them amplifies weight disentanglement. This leads to substantial performance improvements across multiple task arithmetic benchmarks and diverse models. Building on these findings, we provide theoretical and empirical analyses of the neural tangent kernel (NTK) of these models and establish a compelling link between task arithmetic and the spatial localization of the NTK eigenfunctions. Overall, our work uncovers novel insights into the fundamental mechanisms of task arithmetic and offers a more reliable and effective approach to edit pre-trained models through the NTK linearization

Phosphorylation of MAP Kinases crucially controls the response to environmental stress in Dunaliella viridis

The green unicellular microalga Dunaliella viridis has the ability to cope with a wide variety of environmental stressful conditions, such as thermal and osmotic shocks, high PAR, UV radiation and nitrogen deficiency. The lack of a rigid cell wall makes D. viridis an excellent model organism to study stress signaling in eukaryotic unicellular organisms. Mitogen-activated protein kinases (MAPKs) are highly conserved serine/threonine kinases that convert extracellular stimuli into a wide range of responses at both cellular and nuclear levels. In eukaryotic cells, MAPKs are involved in both cell proliferation and differentiation (ERK pathway) and stress responses (JNK and p38 pathways), through protein kinase cascades. Significantly lesser phosphorylation levels of ERK-like protein were observed in D. viridis cultures acclimated to high salinity (3-4 M NaCl). In contrast, JNK-like and p38-like proteins phosphorylation levels increased in stressed cells. Likewise, the efficacy of specific commercial inhibitors of the phosphorylation of ERK (PD98059), JNK (SP600125) and p38 (SB203580) revealed the importance of JNK-like proteins in the maintenance of cell viability, the highlighted participation of p38-like proteins and the non-direct implication of the ERK-like proteins in the acclimatization process. In summary, specific blockade of JNK- and p38-like cascades in stressed cells led to rapid cell death. The behavior of MAPK-like proteins in algae is not known in depth, so the analysis of their mechanism of action, as well as their function in this model microalga, will allow to estimate the fate of unicellular eukaryotic organisms in aquatic ecosystems subjected to environmental stress derived from the conditions prevailing within a framework of global climate change.Peer reviewe

Pi-DUAL: Using Privileged Information to Distinguish Clean from Noisy Labels

Label noise is a pervasive problem in deep learning that often compromises the generalization performance of trained models. Recently, leveraging privileged information (PI) -- information available only during training but not at test time -- has emerged as an effective approach to mitigate this issue. Yet, existing PI-based methods have failed to consistently outperform their no-PI counterparts in terms of preventing overfitting to label noise. To address this deficiency, we introduce Pi-DUAL, an architecture designed to harness PI to distinguish clean from wrong labels. Pi-DUAL decomposes the output logits into a prediction term, based on conventional input features, and a noise-fitting term influenced solely by PI. A gating mechanism steered by PI adaptively shifts focus between these terms, allowing the model to implicitly separate the learning paths of clean and wrong labels. Empirically, Pi-DUAL achieves significant performance improvements on key PI benchmarks (e.g., +6.8% on ImageNet-PI), establishing a new state-of-the-art test set accuracy. Additionally, Pi-DUAL is a potent method for identifying noisy samples post-training, outperforming other strong methods at this task. Overall, Pi-DUAL is a simple, scalable and practical approach for mitigating the effects of label noise in a variety of real-world scenarios with PI

Phosphorylation of MAP kinases crucially controls the response to environmental stress in Dunaliella viridis

El objetivo principal de este estudio fue analizar el papel que llevan a cabo las cascadas de las proteínas tipo MAPKs en la transducción de señales de estrés ambiental en el organismo modelo D. viridis. Se detectó la activación/desactivación y la función de las proteínas tipo MAPKs en este microalga adaptada a condiciones de alta salinidad, ante condiciones de hipersalinidad, alta irradiancia y UV.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

When does Privileged Information Explain Away Label Noise?

Leveraging privileged information (PI), or features available during training but not at test time, has recently been shown to be an effective method for addressing label noise. However, the reasons for its effectiveness are not well understood. In this study, we investigate the role played by different properties of the PI in explaining away label noise. Through experiments on multiple datasets with real PI (CIFAR-N/H) and a new large-scale benchmark ImageNet-PI, we find that PI is most helpful when it allows networks to easily distinguish clean from noisy data, while enabling a learning shortcut to memorize the noisy examples. Interestingly, when PI becomes too predictive of the target label, PI methods often perform worse than their no-PI baselines. Based on these findings, we propose several enhancements to the state-of-the-art PI methods and demonstrate the potential of PI as a means of tackling label noise. Finally, we show how we can easily combine the resulting PI approaches with existing no-PI techniques designed to deal with label noise.Comment: Accepted ICML 2023, Honolul

Propuesta de intervención frente a la desnutrición infantil de 0 a 5 años del municipio de Puerto Carreño - Vichada

No aplicaLa población infantil de 0 a 5 años del municipio de Puerto Carreño – Vichada, continúa afrontando el grave problema de la desnutrición a pesar de los esfuerzos que las entidades estatales vienen realizando para mejorar esta situación. Uno de los vacíos que se han presentado al evaluar el impacto de las acciones de complementariedad alimentaria ha sido la carencia de un diagnóstico del estado nutricional que permita conocer la situación inicial de la intervención y facilite la determinación de un sistema de vigilancia nutricional. Una de las problemáticas más grandes que enfrenta el municipio de Puerto Carreño es el acceso a una alimentación adecuada, lo cual se ve reflejado en el consumo y el estado nutricional de su población en especial la que se encuentra entre 0 a 5 años, según los indicadores económicos y sociales, la tasa de pobreza del municipio es de 29,3% y la de pobreza extrema de 8,4% (DNP, 2016). Esta propuesta está orientada a disminuir las tasas desnutrición de la población infantil de 0 a 5 años en el municipio de Puerto Carreño, bajo un enfoque interinstitucional e intersectorial que implique los actores responsables de brindar una respuesta integral a la problemática de desnutrición en la población de 0 a 5 años del municipio. Desde el sector salud, las acciones orientadas deben ser transversales cuya base se encuentra en una atención sanitaria que permita la identificación de un diagnóstico y tratamiento temprano además de promover estrategias de promoción y prevención.The child population from 0 to 5 years of age in the municipality of Puerto Carreño - Vichada continues to face the serious problem of malnutrition despite the efforts that state entities have been making to improve this situation. One of the gaps that have arisen when evaluating the impact of food complementarity actions has been the lack of a nutritional status diagnosis that allows knowing the initial situation of the intervention and facilitates the determination of a nutritional surveillance system. One of the biggest problems facing the municipality of Puerto Carreño is access to adequate food, which is reflected in the consumption and nutritional status of its population, especially those between 0 to 5 years of age. According to economic and social indicators, the municipality's poverty rate is 29.3% and the extreme poverty rate is 8.4% (DNP, 2016). This proposal is aimed at reducing the malnutrition rates of the child population from 0 to 5 years of age in the municipality of Puerto Carreño, under an inter-institutional and intersectoral approach that involves the actors responsible for providing a comprehensive response to the problem of malnutrition in the population of 0 to 5 years of the municipality. From the health sector, the oriented actions must be transversal, based on health care that allows the identification of early diagnosis and treatment, as well as promoting promotion and prevention strategies

Assessment of platelet REACtivity after transcatheter aortic valve replacement

OBJECTIVES: The REAC-TAVI (Assessment of platelet REACtivity after Transcatheter Aortic Valve Implantation) trial enrolled patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) pre-treated with aspirin + clopidogrel, aimed to compare the efficacy of clopidogrel and ticagrelor in suppressing high platelet reactivity (HPR) after TAVI. BACKGROUND: Current recommendations support short-term use of aspirin + clopidogrel for patients with severe AS undergoing TAVR despite the lack of compelling evidence. METHODS: This was a prospective, randomized, multicenter investigation. Platelet reactivity was measured at 6 different time points with the VerifyNow assay (Accriva Diagnostics, San Diego, California). HPR was defined as (P2Y12 reaction units (PRU) ≥208. Patients with HPR before TAVR were randomized to either aspirin + ticagrelor or aspirin + clopidogrel for 3 months. Patients without HPR continued with aspirin + clopidogrel (registry cohort). The primary endpoint was non-HPR status (PRU <208) in ≥70% of patients treated with ticagrelor at 90 days post-TAVR. RESULTS: A total of 68 patients were included. Of these, 48 (71%) had HPR (PRU 273 ± 09) and were randomized to aspirin + ticagrelor (n = 24, PRU 277 ± 08) or continued with aspirin + clopidogrel (n = 24, PRU 269 ± 49). The remaining 20 patients (29%) without HPR (PRU 133 ± 12) were included in the registry. Overall, platelet reactivity across all the study time points after TAVR was lower in patients randomized to ticagrelor compared with those treated with clopidogrel, including those enrolled in the registry (p < 0.001). The primary endpoint was achieved in 100% of patients with ticagrelor compared with 21% with clopidogrel (p < 0.001). Interestingly, 33% of clopidogrel responder patients at baseline developed HPR status during the first month after TAVR. CONCLUSIONS: HPR to clopidogrel is present in a considerable number of patients with AS undergoing TAVR. Ticagrelor achieves a better and faster effect, providing sustained suppression of HPR to these patients. (Platelet Reactivity After TAVI: A Multicenter Pilot Study [REAC-TAVI]; NCT02224066)