Solving multiscale elliptic problems by sparse radial basis function neural networks

Machine learning has been successfully applied to various fields of scientific computing in recent years. In this work, we propose a sparse radial basis function neural network method to solve elliptic partial differential equations (PDEs) with multiscale coefficients. Inspired by the deep mixed residual method, we rewrite the second-order problem into a first-order system and employ multiple radial basis function neural networks (RBFNNs) to approximate unknown functions in the system. To aviod the overfitting due to the simplicity of RBFNN, an additional regularization is introduced in the loss function. Thus the loss function contains two parts: the $L_2$ loss for the residual of the first-order system and boundary conditions, and the $\ell_1$ regularization term for the weights of radial basis functions (RBFs). An algorithm for optimizing the specific loss function is introduced to accelerate the training process. The accuracy and effectiveness of the proposed method are demonstrated through a collection of multiscale problems with scale separation, discontinuity and multiple scales from one to three dimensions. Notably, the $\ell_1$ regularization can achieve the goal of representing the solution by fewer RBFs. As a consequence, the total number of RBFs scales like $\mathcal{O}(\varepsilon^{-n\tau})$, where $\varepsilon$ is the smallest scale, $n$ is the dimensionality, and $\tau$ is typically smaller than $1$. It is worth mentioning that the proposed method not only has the numerical convergence and thus provides a reliable numerical solution in three dimensions when a classical method is typically not affordable, but also outperforms most other available machine learning methods in terms of accuracy and robustness.Comment: 23 pages, 12 figure

Why growth equals power - and why it shouldn't : constructing visions of China

When discussing the success of China's transition from socialism, there is a tendency to focus on growth figures as an indication of performance. Whilst these figures are indeed impressive, we should not confuse growth with development and assume that the former necessarily automatically generates the latter. Much has been done to reduce poverty in China, but the task is not as complete as some observers would suggest; particularly in terms of access to health, education and welfare, and also in dealing with relative (rather than absolute) depravation and poverty. Visions of China have been constructed that exaggerate Chinese development and power in the global system partly to serve political interests, but partly due to the failure to consider the relationship between growth and development, partly due to the failure to disaggregate who gets what in China, and partly due to the persistence of inter-national conceptions of globalised production, trade, and financial flows

The prognostic value of postoperative radiotherapy in right tumor for lung related death: based on SEER database and real-world data

BackgroundPostoperative radiotherapy (PORT) is a therapeutic strategy for patients with non-small cell lung cancer (NSCLC). Nevertheless, some studies suggesting PORT does not improve overall survival (OS) including Lung ART phase III trial. The role of PORT and high-risk groups need to be confirmed.MethodsPatients from the Surveillance, Epidemiology, and End Results program (SEER) from 2004 to 2015 were eligible. Aged ≥18 years with stage IIIA-N2 NSCLC, accepted PORT or not were considered for the study. Cox regression analyses and multivariate competing risk model were performed. Propensity score matching (PSM) was conducted. Data from a single-center study in China were used for validation.ResultsIn all patients with IIIA-N2 NSCLC, death from respiratory illness increased year by year, with right lung-related deaths accounting for the main proportion. In SEER database, PORT was detrimental for OS after PSM (hazard ratio [HR], 1.088; 95% CI, 1.088–1.174; P = 0.031), with a same trend for death from the lungs (HR, 1.13; 95% CI, 1.04–1.22; P = 0.005). Right tumor receiving PORT were prone to death from lung disease(HR, 1.14; 95% CI, 1.02–1.27; P = 0.018). In China single-center cohort, PORT was significantly correlated with deteriorated OS (HR 1.356; 95% CI 1.127–1.632; P <0.01), especially in the right laterality (HR 1.365; 95% CI 1.062–1.755; P = 0.015).ConclusionsPORT was a risk factor for stage IIIA-N2 NSCLC patients, particularly with characters of right laterality, male sex, age ≥65 years, and advanced tumor stage. These patients are more likely to death from lung disease after PORT

Machine Unlearning of Pre-trained Large Language Models

This study investigates the concept of the `right to be forgotten' within the context of large language models (LLMs). We explore machine unlearning as a pivotal solution, with a focus on pre-trained models--a notably under-researched area. Our research delineates a comprehensive framework for machine unlearning in pre-trained LLMs, encompassing a critical analysis of seven diverse unlearning methods. Through rigorous evaluation using curated datasets from arXiv, books, and GitHub, we establish a robust benchmark for unlearning performance, demonstrating that these methods are over $10^5$ times more computationally efficient than retraining. Our results show that integrating gradient ascent with gradient descent on in-distribution data improves hyperparameter robustness. We also provide detailed guidelines for efficient hyperparameter tuning in the unlearning process. Our findings advance the discourse on ethical AI practices, offering substantive insights into the mechanics of machine unlearning for pre-trained LLMs and underscoring the potential for responsible AI development.Comment: ACL 2024 main. Code and data at https://github.com/yaojin17/Unlearning_LL

Responses of nitrogen utilization and apparent nitrogen loss to different control measures in the wheat and maize rotation sytsem

Nitrogen (N) is an essential macronutrient for plant growth and excessive application rates can decrease crop yield and increase N loss into the environment. Field experiments were carried out to understand the effects of N fertilizers on N utilization, crop yield and net income in wheat and maize rotation system of the North China Plain (NCP). Compared to farmers’ N rate (FN), the yield of wheat and maize in reduction N rate by 21–24% based on FN (RN) was improved by 451 kg ha-1, N uptakes improved by 17 kg ha-1 and net income increased by 1671 CNY ha-1, while apparent N loss was reduced by 156 kg ha-1. The controlled-release fertilizer with a 20% reduction of RN (CRF80%), a 20% reduction of RN together with dicyandiamide (RN80%+DCD) and a 20% reduction of RN added with nano-carbon (RN80%+NC) all resulted in an improvement in crop yield and decreased the apparent N losses compared to RN. Contrasted with RN80%+NC, the total crop yield in RN80%+DCD improved by 1185 kg ha-1, N uptake enhanced by 9 kg ha-1 and net income increased by 3929 CNY ha-1, while apparent N loss was similar. Therefore, a 37–39% overall decrease in N rate compared to farmers plus the nitrification inhibitor, DCD, was effective N control measure that increased crop yields, enhanced N efficiencies, and improved economic benefits, while mitigating apparent N loss. There is considerable scope for improved N use effieincy in the intensive wheat -maize rotation of the NCP

A six-generation Chinese family in haplogroup B4C1C exhibits high penetrance of 1555A > G-induced hearing Loss

<p>Abstract</p> <p>Background</p> <p>The 1555A > G mutation is the most common cause of aminoglycoside-induced and non-syndromic deafness. However, the variable clinical phenotype and incomplete penetrance of A1555G-induced hearing loss complicate our understanding of this mutation. Environmental factors, nuclear genes, mitochondrial haplotypes/variants and a possible threshold effect have been reported to may be involved in its manifestation.</p> <p>Methods</p> <p>Here, we performed a clinical, molecular, genetic and phylogenic analysis in a six-generation Chinese family.</p> <p>Results</p> <p>A clinical evaluation revealed that affected individuals without aminoglycoside exposure developed hearing loss extending gradually from 12000 Hz to 8000 Hz and then to 4000 Hz. Using pyrosequencing, we detected an identical homoplasmic 1555A > G mutation in all individuals except one. We did not find any correlation between the mutation load and the severity of hearing loss. T123N coexisted with the 1555A > G mutation in six affected subjects in our pedigree. Analysis of the complete mtDNA genome of this family revealed that this family belonged to haplotype B4C1C and exhibited high penetrance. Upon the inclusion of subjects that had been exposed to aminoglycosides, the penetrance of the hearing loss was 63.6%.; without exposure to aminoglycosides, it was 51.5%. This pedigree and another reported Chinese pedigree share the same haplotype (B4C1C) and lack functionally significant mitochondrial tRNA variants, but nevertheless they exhibit a different penetrance of hearing loss.</p> <p>Conclusions</p> <p>Our results imply that the factors responsible for the higher penetrance and variable expression of the deafness associated with the 1555A > G mutation in this pedigree may not be mtDNA haplotype/variants, but rather nuclear genes and/or aminoglycosides.</p

Case Report: A FBN1 frameshift-and-nonsense mutation and aortic dissection in Marfan syndrome

BackgroundMarfan syndrome (MFS) is an autosomal dominant connective tissue disorder primarily affecting the cardiovascular, ocular, and skeletal systems. Cardiovascular complications are the leading cause of mortality in MFS. Mutations in the FBN1 gene, which encodes fibrillin-1, a critical extracellular matrix protein, are the predominant cause of the disorder.Case presentationOn March 11, 2024, we diagnosed a 30-year-old female proband with MFS based on the revised Ghent criteria, presenting with aortic root aneurysm, aortic dissection, multiple skeletal abnormalities, and a family history of MFS. Whole-exome sequencing followed by Sanger sequencing confirmation identified a novel inherited insertion mutation (c.4991dupA) in exon 40 of the FBN1 gene. We performed valve-sparing aortic root replacement (David Procedure) and total aortic arch replacement using a tetrafurcated graft, along with the implantation of a specially designed frozen elephant trunk in the descending aorta (Sun's Procedure). Postoperatively, the patient underwent biweekly clinical follow-ups for three months. No treatment-related adverse events were reported during the monitoring period.ConclusionThe diagnosis of MFS requires an integrated approach, combining clinical manifestations, imaging studies, and genetic analysis. This novel mutation is associated with severe skeletal manifestations and life-threatening cardiovascular abnormalities, underscoring its clinical relevance. Its association with aggressive phenotypes enhances genotype-phenotype correlations. Importantly, these findings highlight the imperative need for early intervention in high-risk individuals by bridging genetic discovery to clinical practice

Analysis of the Accumulation of Major Aroma Components in Japanese Apricot Fruit (Prunus mume Siebold et Zucc.) during Ripening

The major characteristic aroma components of Japanese apricot fruit grown in Dayi county, Sichuan Province were determined by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) based on odor activity values (OAVs). The pattern of accumulation of the major aroma components was investigated by analysis of aroma precursors and their correlation with climate factors was analyzed. The results showed that ethyl butyrate, β-myrcene, ethyl 3-methyl-butyrate, benzaldehyde and nonanal were the major characteristic aroma substances of Japanese apricot fruit, and C6 and C9 compounds were the major aroma components. C6 aroma substances had a high correlation with unsaturated fatty acid precursors. There was a positive correlation between the synthesis of C6 and C9 aroma substances. Climate significantly affected aroma accumulation during fruit ripening. Precipitation was the key factor affecting the content of C6 substances in the early ripening stage, mainly affecting the accumulation of bound hexenol. At the late stage of maturity, air temperature had a great influence on the content of free substances such as hexanol and hexanoic acid. These results provide a basis for follow-up research to analyze the flavor and quality of processed Japanese apricot fruit, explore the effects of climate factors on Japanese apricot fruit and its products, and identify the production region of raw materials and processed products for flavor evaluation