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781.
李欣
(2022-08-23 20:20):
#paper 10.1016/j.devcel.2021.01.014
Histone H3 lysine 4 trimethylation in sperm is transmitted to the embryo and associated with diet-induced phenotypes in the offspring
精子表观基因组对环境压力源的敏感不仅限于宫内发育期,可能贯穿整个生命周期。不良饮食可致小鼠精子表观修饰改变,精子发生过程中KDM1A过表达介导精子启动子H3K4me2/3差异富集、子代出生后早期死亡及大量先天性异常,而精子H3K4me3水平的变化是否可从精子传递到植入前胚胎尚未得到证实。此外,微量营养素缺乏,包括叶酸缺乏症,如何影响哺乳动物精子染色质在全基因组水平上的建立和传递尚不清楚。
本研究旨在探究:(1)断奶后叶酸缺乏会改变精子H3K4me3的富集吗?(2)受损的精子表观基因组是否会受到另一种表观基因组调节剂(叶酸缺乏)的影响并导致后代发育缺陷增强?(3)精子H3K4me3富集变化是否在胚胎中持续存在,它们是否与胚胎基因表达和发育异常有关?作者得出结论:精子H3K4me3传递到胚胎并影响基因表达和发育,增加了暴露于多种环境压力可累积影响表观基因组的可能性。表观遗传错误可以在精子中积累并恶化子代的发育结局。
Abstract:
A father's lifestyle impacts offspring health; yet, the underlying molecular mechanisms remain elusive. We hypothesized that a diet that changes methyl donor availability will alter the sperm and embryo epigenomes …
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A father's lifestyle impacts offspring health; yet, the underlying molecular mechanisms remain elusive. We hypothesized that a diet that changes methyl donor availability will alter the sperm and embryo epigenomes to impact embryonic gene expression and development. Here, we demonstrate that a folate-deficient (FD) diet alters histone H3 lysine 4 trimethylation (H3K4me3) in sperm at developmental genes and putative enhancers. A subset of H3K4me3 alterations in sperm are retained in the pre-implantation embryo and associated with deregulated embryonic gene expression. Using a genetic mouse model in which sires have pre-existing altered H3K4me2/3 in sperm, we show that a FD diet exacerbates alterations in sperm H3K4me3 and embryonic gene expression, leading to an increase in developmental defect severity. These findings imply that paternal H3K4me3 is transmitted to the embryo and influences gene expression and development. It further suggests that epigenetic errors can accumulate in sperm to worsen offspring developmental outcomes.
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782.
张浩彬
(2022-08-23 15:36):
#paper doi: 10.1080/10618600.2021.1909601 Moon, S. J., Jeon, J.-J., Lee, J. S. H., & Kim, Y. (2021). Learning Multiple Quantiles With Neural Networks. Journal of Computational and Graphical Statistics, 30(4), 1238–1248.
提出了一个神经网络模型,用于估计满足非交叉属性的多个条件分位数。 传统的分位数回归会面临一个问题就是可能会出现分位数交叉,即85%分位数的值大于90%分位数的值。一般来说有两种处理策略:(1)调整转转模型参数;(2)将模型空间限制为非交叉分位数。本文采用了第二种思路,借鉴了线性非交叉分位数回归(非交叉SVR中的一个策略,这个策略问题在于计算量可能比较大),提出了一种具有不等式约束的非交叉分位数神经网络模型(把不等式约束用在了神经网络隐藏层)。
解决了交叉问题,第二个贡献是计算效率。为了使用一阶优化方法,文章开发了一种新算法来拟合所提出的模型。 该算法在没有需要多项式计算时间的投影梯度步骤的情况下给出了几乎最优的解决方案。
IF:1.400Q2
Journal of Computational and Graphical Statistics,
2021.
DOI: 10.1080/10618600.2021.1909601
Abstract:
We present a neural network model for estimation of multiple conditional quantiles that satisfies the noncrossing property. Motivated by linear noncrossing quantile regression, we propose a noncrossing quantile neural network …
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We present a neural network model for estimation of multiple conditional quantiles that satisfies the noncrossing property. Motivated by linear noncrossing quantile regression, we propose a noncrossing quantile neural network model with inequality constraints. In particular, to use the first-order optimization method, we develop a new algorithm for fitting the proposed model. This algorithm gives a nearly optimal solution without the projected gradient step that requires polynomial computation time. We compare the performance of our proposed model with that of existing neural network models on simulated and real precipitation data. Supplementary materials for this article are available online.
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783.
徐炳祥
(2022-08-18 17:16):
#paper doi: 10.1038/s41586-022-05030-3 Nature, 2022, Brown-fat-mediated tumour suppression by cold-altered global metabolism。有氧糖酵解是肿瘤细胞获取能量的主要方式,此过程需消耗大量葡萄糖,因此肿瘤组织对葡萄糖饥饿敏感。而暴露于寒冷环境中的动物通过棕色脂肪细胞(BAT)活化、白色脂肪细胞(WAT)棕色化进行非战栗产热的过程也需消耗大量葡萄糖。因此寒冷环境下的肿瘤患者势必存在BAT和肿瘤细胞之间的葡萄糖竞争,此竞争有可能使肿瘤组织处于葡萄糖饥饿状态从而抑制肿瘤生长。本文主要通过将异体肿瘤移植小鼠至于寒冷环境下对这一假设进行了验证。此为将代谢与肿瘤联系起来的又一新角度。
Abstract:
Glucose uptake is essential for cancer glycolysis and is involved in non-shivering thermogenesis of adipose tissues. Most cancers use glycolysis to harness energy for their infinite growth, invasion and metastasis. …
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Glucose uptake is essential for cancer glycolysis and is involved in non-shivering thermogenesis of adipose tissues. Most cancers use glycolysis to harness energy for their infinite growth, invasion and metastasis. Activation of thermogenic metabolism in brown adipose tissue (BAT) by cold and drugs instigates blood glucose uptake in adipocytes. However, the functional effects of the global metabolic changes associated with BAT activation on tumour growth are unclear. Here we show that exposure of tumour-bearing mice to cold conditions markedly inhibits the growth of various types of solid tumours, including clinically untreatable cancers such as pancreatic cancers. Mechanistically, cold-induced BAT activation substantially decreases blood glucose and impedes the glycolysis-based metabolism in cancer cells. The removal of BAT and feeding on a high-glucose diet under cold exposure restore tumour growth, and genetic deletion of Ucp1-the key mediator for BAT-thermogenesis-ablates the cold-triggered anticancer effect. In a pilot human study, mild cold exposure activates a substantial amount of BAT in both healthy humans and a patient with cancer with mitigated glucose uptake in the tumour tissue. These findings provide a previously undescribed concept and paradigm for cancer therapy that uses a simple and effective approach. We anticipate that cold exposure and activation of BAT through any other approach, such as drugs and devices either alone or in combination with other anticancer therapeutics, will provide a general approach for the effective treatment of various cancers.
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784.
颜林林
(2022-08-18 00:34):
#paper doi:10.1186/s12859-022-04876-8 BMC Bioinformatics, 2022, IMSE: interaction information attention and molecular structure based drug drug interaction extraction. 让机器自动读取大量论文,并从中提炼有用信息,是很多人的梦想,BERT等模型让这件事逐步成为现实。本文便是基于PubMed摘要和PMC全文,进行BioBERT预训练,并由此改进DDIExtraction 2013的任务执行性能,该任务旨在从生物医学领域的自由文本中提取药物间相互作用(drug-drug interaction, DDI)。关于这项任务已有不少研究工作,本文引入了交互注意力向量(interaction attention vector),以及加入药物分子结构(以利用其特征空间信息)等,来改善模型性能及可解释性,取得不错的效果。
Abstract:
BACKGROUND: Extraction of drug drug interactions from biomedical literature and other textual data is an important component to monitor drug-safety and this has attracted attention of many researchers in healthcare. …
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BACKGROUND: Extraction of drug drug interactions from biomedical literature and other textual data is an important component to monitor drug-safety and this has attracted attention of many researchers in healthcare. Existing works are more pivoted around relation extraction using bidirectional long short-term memory networks (BiLSTM) and BERT model which does not attain the best feature representations.RESULTS: Our proposed DDI (drug drug interaction) prediction model provides multiple advantages: (1) The newly proposed attention vector is added to better deal with the problem of overlapping relations, (2) The molecular structure information of drugs is integrated into the model to better express the functional group structure of drugs, (3) We also added text features that combined the T-distribution and chi-square distribution to make the model more focused on drug entities and (4) it achieves similar or better prediction performance (F-scores up to 85.16%) compared to state-of-the-art DDI models when tested on benchmark datasets.CONCLUSIONS: Our model that leverages state of the art transformer architecture in conjunction with multiple features can bolster the performances of drug drug interation tasks in the biomedical domain. In particular, we believe our research would be helpful in identification of potential adverse drug reactions.
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785.
颜林林
(2022-08-17 23:55):
#paper doi:10.1016/j.xgen.2022.100168 Cell Genomics, 2022, Systematic single-variant and gene-based association testing of thousands of phenotypes in 394,841 UK Biobank exomes. 高通量测序技术的发展、降价和普及,拉动了一大批人类群体基因组学的研究。本文又是这样一篇大规模人群的全外显子组数据及其分析结果的发布,该人群来自UK biobank,入组人数超过39万。文章开发并使用了一个混合模型分析框架SAIGE-GENE,会同时考虑点突变的水平、基因水平的突变负荷、以及两者的组合,由此分析与4529种疾病或表型(包括II型糖尿病、心脏代谢等)存在关联关系的各类罕见突变。在此基础上,本文还提供了一个在线浏览器Genebass,以展示这些表型相关的罕见突变。作为一个实例,文章在结果部分还特意强调了所发现的一个基因SCRIB,以及它与MRI脑成像特征之间的关系。类似的大规模人群基因组分析文章层出不穷,分析方法各有侧重或不同,若有可能,倒是值得研究下它们之间的方法差异,是否可能对所报道的结果产生影响。
Abstract:
Genome-wide association studies have successfully discovered thousands of common variants associated with human diseases and traits, but the landscape of rare variations in human disease has not been explored at …
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Genome-wide association studies have successfully discovered thousands of common variants associated with human diseases and traits, but the landscape of rare variations in human disease has not been explored at scale. Exome-sequencing studies of population biobanks provide an opportunity to systematically evaluate the impact of rare coding variations across a wide range of phenotypes to discover genes and allelic series relevant to human health and disease. Here, we present results from systematic association analyses of 4,529 phenotypes using single-variant and gene tests of 394,841 individuals in the UK Biobank with exome-sequence data. We find that the discovery of genetic associations is tightly linked to frequency and is correlated with metrics of deleteriousness and natural selection. We highlight biological findings elucidated by these data and release the dataset as a public resource alongside the Genebass browser for rapidly exploring rare-variant association results.
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786.
张德祥
(2022-08-16 10:19):
#paper DOI https://doi.org/10.1007/s10339-020-00981-9 Do Process-1 simulations generate the epistemic feelings that drive Process-2 decision making? 如何用范畴数学来描述人类过程1过程2的思考方式(快思考慢思考),并且可以用来分析心流的体验(p31),这种分析结合了全局神经工作空间及元认知。形成了一个人类认知的高级架构。慢思考过程2是快思考过程1的一个高阶功能或过程1的上层调度机制(其中包含了人类的高级情感:问题求解过程中的怀疑焦虑挫折兴奋等)。思维问题解决的慢过程由于与外界互动少,主要以内感受为主,所以内部情绪活动较多(即怀疑焦虑兴奋等)。机制底层仍然是贝叶斯的信念、confidence。
Abstract:
We apply previously developed Chu space and Channel Theory methods, focusing on the construction of Cone-Cocone Diagrams (CCCDs), to study the role of epistemic feelings, particularly feelings of confidence, in …
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We apply previously developed Chu space and Channel Theory methods, focusing on the construction of Cone-Cocone Diagrams (CCCDs), to study the role of epistemic feelings, particularly feelings of confidence, in dual process models of problem solving. We specifically consider "Bayesian brain" models of probabilistic inference within a global neuronal workspace architecture. We develop a formal representation of Process-1 problem solving in which a solution is reached if and only if a CCCD is completed. We show that in this representation, Process-2 problem solving can be represented as multiply iterated Process-1 problem solving and has the same formal solution conditions. We then model the generation of explicit, reportable subjective probabilities from implicit, experienced confidence as a simulation-based, reverse engineering process and show that this process can also be modeled as a CCCD construction.
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787.
惊鸿
(2022-08-14 18:12):
#paper doi:10.1101/2022.08.08.503198 Bilallelic germline mutations in MAD1L1 induce a novel syndrome of aneuploidy with high tumor susceptibility
MAD1L1是编码纺锤体组装检查点 (SAC) 蛋白MAD1的基因,发生在一名36岁的患有十几个肿瘤的女性身上,包括五个恶性肿瘤。外周血细胞的功能研究表明缺乏全长蛋白质和SAC反应不足,导致细胞遗传学和单细胞 (sc) 检测到约30-40% 的非整倍体细胞DNA分析。对患者血细胞的scRNA-seq分析确定了线粒体应激伴随全身炎症,干扰素和NFkB信号增强。MAD1L1突变还导致 γ δ T细胞的特异性克隆扩增,增加了18号染色体并增强了细胞毒性,以及具有慢性淋巴细胞白血病细胞特征的染色体12增益和转录组特征的中间b细胞。这些数据表明MAD1L1突变是一种新的具有全身炎症和前所未有的肿瘤易感性的非整倍体综合征的原因。
仅仅一个基因片段就可以给全身带来变化,这些变化有好有坏,所以基因编辑不是消消乐,是一个严谨的技术,这是一个基因工程师应有的心态
bioRxiv,
2022.
DOI: 10.1101/2022.08.08.503198
Abstract:
Aneuploidy is a frequent feature of human tumors. Germline mutations leading to aneuploidy are very rare in humans, and their tumor-promoting properties are mostly unknown at the molecular level. We …
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Aneuploidy is a frequent feature of human tumors. Germline mutations leading to aneuploidy are very rare in humans, and their tumor-promoting properties are mostly unknown at the molecular level. We report here novel germline biallelic mutations in MAD1L1, the gene encoding the Spindle Assembly Checkpoint (SAC) protein MAD1, in a 36-year-old female with a dozen of neoplasias, including five malignant tumors. Functional studies in peripheral blood cells demonstrated lack of full-length protein and deficient SAC response, resulting in ∼30-40% of aneuploid cells as detected by cytogenetic and single-cell (sc) DNA analysis. scRNA-seq analysis of patient blood cells identified mitochondrial stress accompanied by systemic inflammation with enhanced interferon and NFkB signaling. The inference of chromosomal aberrations from scRNA-seq analysis detected inflammatory signals both in aneuploid and euploid cells, suggesting a non-cell autonomous response to aneuploidy. In addition to random aneuploidies, MAD1L1 mutations resulted in specific clonal expansions of γδ T-cells with chromosome 18 gains and enhanced cytotoxic profile, as well as intermediate B-cells with chromosome 12 gains and transcriptomic signatures characteristic of chronic lymphocytic leukemia cells. These data point to MAD1L1 mutations as the cause of a new aneuploidy syndrome with systemic inflammation and unprecedented tumor susceptibility.
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788.
DeDe宝
(2022-08-14 17:53):
#paper doi:10.1016/j.cub.2020.03.006 Current Biology,2020,Stress Disrupts Human Hippocampal-Prefrontal Function during Prospective Spatial Navigation and Hinders Flexible Behavior.前瞻对空间导航的规划非常重要,前瞻性规划部分依赖于情景记忆检索机制,而检索能力受到压力的负面影响。本研究采用虚拟空间导航任务,检查压力是否以及如何影响前瞻和决策行为。研究结果表明,压力可能对新目标的导航规划神经机制产生影响。从行为角度,压力限制了检索landmark的能力和有效导航的能力,降低了采取新捷径的可能性,并增加了达到目标的路径长度。从神经角度,压力会降低海马后部、FPC、广义CCN脑区和其他与记忆相关脑区(如角回)在新路程规划的神经活动。
Abstract:
The ability to anticipate and flexibly plan for the future is critical for achieving goal-directed outcomes. Extant data suggest that neural and cognitive stress mechanisms may disrupt memory retrieval and …
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The ability to anticipate and flexibly plan for the future is critical for achieving goal-directed outcomes. Extant data suggest that neural and cognitive stress mechanisms may disrupt memory retrieval and restrict prospective planning, with deleterious impacts on behavior. Here, we examined whether and how acute psychological stress influences goal-directed navigational planning and efficient, flexible behavior. Our methods combined fMRI, neuroendocrinology, and machine learning with a virtual navigation planning task. Human participants were trained to navigate familiar paths in virtual environments and then (concurrent with fMRI) performed a planning and navigation task that could be most efficiently solved by taking novel shortcut paths. Strikingly, relative to non-stressed control participants, participants who performed the planning task under experimentally induced acute psychological stress demonstrated (1) disrupted neural activity critical for mnemonic retrieval and mental simulation and (2) reduced traversal of shortcuts and greater reliance on familiar paths. These neural and behavioral changes under psychological stress were tied to evidence for disrupted neural replay of memory for future locations in the spatial environment, providing mechanistic insight into why and how stress can alter planning and foster inefficient behavior.
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789.
颜林林
(2022-08-13 23:36):
#paper doi:10.1038/s41586-022-04774-2 Nature, 2022, Stromal changes in the aged lung induce an emergence from melanoma dormancy. 众所周知,年龄是肿瘤发病的最重要因素。这篇文章将培养的黑色素瘤细胞(其中部分细胞系使用质粒体系过表达WNT通路相关基因),注入年轻与年老小鼠,观察其成瘤过程及表型变化,其中还穿插腹腔注射等干预实验,之后取样后对肺组织进行免疫组化、蛋白组(质谱)等检测,用以揭示衰老与肿瘤发生之间的关系。该研究发现,在老化的肺微环境中,黑色素瘤并未快速生长,反而是受到了抑制,处于一种休眠状态,但同时该微环境又会促进其转移扩散,使黑色素瘤细胞能够在转移性生态位中有效传播和播种。本文同时还详细研究了WNT通路在此过程中的作用,以及酪氨酸激酶受体 AXL 和 MER 对肿瘤休眠的促进再激活。这些结果为后续研究肿瘤休眠及肺组织微环境之间的关系提供了重要信息,同时也提示在肿瘤治疗过程中有必要关注年龄因素的影响。
Abstract:
Disseminated cancer cells from primary tumours can seed in distal tissues, but may take several years to form overt metastases, a phenomenon that is termed tumour dormancy. Despite its importance …
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Disseminated cancer cells from primary tumours can seed in distal tissues, but may take several years to form overt metastases, a phenomenon that is termed tumour dormancy. Despite its importance in metastasis and residual disease, few studies have been able to successfully characterize dormancy within melanoma. Here we show that the aged lung microenvironment facilitates a permissive niche for efficient outgrowth of dormant disseminated cancer cells-in contrast to the aged skin, in which age-related changes suppress melanoma growth but drive dissemination. These microenvironmental complexities can be explained by the phenotype switching model, which argues that melanoma cells switch between a proliferative cell state and a slower-cycling, invasive state. It was previously shown that dermal fibroblasts promote phenotype switching in melanoma during ageing. We now identify WNT5A as an activator of dormancy in melanoma disseminated cancer cells within the lung, which initially enables the efficient dissemination and seeding of melanoma cells in metastatic niches. Age-induced reprogramming of lung fibroblasts increases their secretion of the soluble WNT antagonist sFRP1, which inhibits WNT5A in melanoma cells and thereby enables efficient metastatic outgrowth. We also identify the tyrosine kinase receptors AXL and MER as promoting a dormancy-to-reactivation axis within melanoma cells. Overall, we find that age-induced changes in distal metastatic microenvironments promote the efficient reactivation of dormant melanoma cells in the lung.
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790.
魏魏魏
(2022-08-12 20:21):
#paper doi:10.1111/1467-8721.01259 Current Directions in Psychological Science, (2003), Understanding Families as Systems. 这是一篇比较古老的文献了,而且属于综述性质的文献,只是因为对于探讨父亲或母亲在子女心理发展中的作用有价值才阅读的。作者认为,应该把家庭看作是有婚姻关系和亲子关系等多个子系统构成的一个整体系统,这个系统是有层次的,像一个生命一样能够对外界刺激作出反应并适应外界的变化。这样的观点有助于我们深刻理解儿童心理发展,比如,基于上述家庭观,我们对亲子依恋、儿童气质类型的理解不再是静态的且二元的,应该看到夫妻关系或婚姻关系对儿童心理发展的影响,所以,现在我们的研究一般都把夫妻关系品质或父母任何一方的幸福感等作为控制变量。把家庭看作能够对外界刺激做出反应的系统也是有意义的,这意味着家庭系统内部不同层次之间是相互影响的,不同家庭发展阶段儿童受到的影响也是不同的,因此,采用追踪研究对儿童心理发展进行研究是有必要的。这篇文献对具体的实证研究有很大的启发。
Abstract:
In this article, we discuss recent research that has arisen from theoretical and conceptual models that use a systems metaphor for understanding families. We suggest that research stimulated by such …
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In this article, we discuss recent research that has arisen from theoretical and conceptual models that use a systems metaphor for understanding families. We suggest that research stimulated by such models leads social scientists in new and important directions in understanding the social and emotional development of children in their families. These models view development as resulting from the dynamic transactions across multiple levels of family systems, which regulate a child's behavior. Thus, these models are important in considering multiple influences on development and adaptation.
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791.
颜林林
(2022-08-12 07:42):
#paper doi:10.1016/j.ccell.2022.07.002 Cancer Cell, 2022, Integrative analysis of drug response and clinical outcome in acute myeloid leukemia. 这是一项关于AML(急性骨髓性白血病)的长达10年的真实世界临床研究,收集了来自多个中心的 805 名患者(942 个样本),对样本进行基因组和转录组的测序,同时使用离体细胞培养进行药物反应实验,此外还利用NLP技术整理和分析患者的病历数据。在数据分析方面,使用反卷积方法,通过转录组数据推断出样本的细胞类群组成,并结合临床信息和组学数据分析结果,识别出影响药物响应情况的因素(如年龄、基因表达、细胞分化状态等)。所建立的模型,揭示了单个基因 PEAR1 是患者生存的最强预测因子之一。所形成的数据集,也提供了一个在线交互式网站进行分析展示。分析方面基本都是很多生信数据挖掘类文章的常见套路,并没有特别新颖之处,但得益于长时间积累的队列及其完整的临床信息,作为一个重要的数据集资源,以及单病种的真实世界研究实例,也还是很有价值的。此外,关于药物响应的细胞实验部分相对独立,与患者预后进行关联解释并不容易,大概也是为了提升文章份量而加入的。
Abstract:
Acute myeloid leukemia (AML) is a cancer of myeloid-lineage cells with limited therapeutic options. We previously combined ex vivo drug sensitivity with genomic, transcriptomic, and clinical annotations for a large …
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Acute myeloid leukemia (AML) is a cancer of myeloid-lineage cells with limited therapeutic options. We previously combined ex vivo drug sensitivity with genomic, transcriptomic, and clinical annotations for a large cohort of AML patients, which facilitated discovery of functional genomic correlates. Here, we present a dataset that has been harmonized with our initial report to yield a cumulative cohort of 805 patients (942 specimens). We show strong cross-cohort concordance and identify features of drug response. Further, deconvoluting transcriptomic data shows that drug sensitivity is governed broadly by AML cell differentiation state, sometimes conditionally affecting other correlates of response. Finally, modeling of clinical outcome reveals a single gene, PEAR1, to be among the strongest predictors of patient survival, especially for young patients. Collectively, this report expands a large functional genomic resource, offers avenues for mechanistic exploration and drug development, and reveals tools for predicting outcome in AML.
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792.
张浩彬
(2022-08-11 16:10):
#paper 10.48550/arXiv.1901.10738
Unsupervised Scalable Representation Learning for Multivariate Time Series
论文关键是:正负样本构造, triplet loss以及因果空洞卷积
适用:该无监督学习模型可以用于不定长的序列;短序列及长序列均可使用;
1.正负样本构造:对于某序列,随机选择长度,构造一个子序列。在这个子序列中,随机抽样一个子序列作为正样本;从其他序列中随机抽样作为一个负样本
2.改造的triplet loss
3. exponentially dilated causal convolutions作为特征提取器代替传统的rnn、lstm
结果表明由于现有的无监督方法,并且不差于有监督方法。
arXiv,
2019.
DOI: 10.48550/arXiv.1901.10738
Abstract:
Time series constitute a challenging data type for machine learning algorithms, due to their highly variable lengths and sparse labeling in practice. In this paper, we tackle this challenge by …
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Time series constitute a challenging data type for machine learning algorithms, due to their highly variable lengths and sparse labeling in practice. In this paper, we tackle this challenge by proposing an unsupervised method to learn universal embeddings of time series. Unlike previous works, it is scalable with respect to their length and we demonstrate the quality, transferability and practicability of the learned representations with thorough experiments and comparisons. To this end, we combine an encoder based on causal dilated convolutions with a novel triplet loss employing time-based negative sampling, obtaining general-purpose representations for variable length and multivariate time series.
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793.
张浩彬
(2022-08-11 16:09):
#paper https://doi.org/10.48550/arXiv.2103.07719
Spectral Temporal Graph Neural Network for Multivariate Time-series Forecasting
对输入使用“Latent Correlation Layer”自动生成图结构;对图结构输入StemGNN层;
该层首先使用GFT(图傅里叶变换)将图转为谱矩阵( 其中每个节点的单变量时间序列变为线性独立),然后使用离散傅里叶变换对每个单变量分量转到频域,并利用一维卷积以及GLU提取特征模式,再通过逆离散傅里叶变换变回时域。另外,模型产生一个预测损失(对未来值),一个回溯损失(对历史值),对两个损失合并作为联合的损失函数。
arXiv,
2021.
DOI: 10.48550/arXiv.2103.07719
Abstract:
Multivariate time-series forecasting plays a crucial role in many real-world applications. It is a challenging problem as one needs to consider both intra-series temporal correlations and inter-series correlations simultaneously. Recently, …
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Multivariate time-series forecasting plays a crucial role in many real-world applications. It is a challenging problem as one needs to consider both intra-series temporal correlations and inter-series correlations simultaneously. Recently, there have been multiple works trying to capture both correlations, but most, if not all of them only capture temporal correlations in the time domain and resort to pre-defined priors as inter-series relationships. In this paper, we propose Spectral Temporal Graph Neural Network (StemGNN) to further improve the accuracy of multivariate time-series forecasting. StemGNN captures inter-series correlations and temporal dependencies \textit{jointly} in the \textit{spectral domain}. It combines Graph Fourier Transform (GFT) which models inter-series correlations and Discrete Fourier Transform (DFT) which models temporal dependencies in an end-to-end framework. After passing through GFT and DFT, the spectral representations hold clear patterns and can be predicted effectively by convolution and sequential learning modules. Moreover, StemGNN learns inter-series correlations automatically from the data without using pre-defined priors. We conduct extensive experiments on ten real-world datasets to demonstrate the effectiveness of StemGNN. Code is available at this https URL
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794.
张浩彬
(2022-08-11 12:06):
#paper 10.1137/1.9781611976700.60
Attention-Based Autoregression for Accurate and Efficient Multivariate Time Series Forecasting
AttnAR:提出一个新模型,结合了注意力机制将变量的相关转化为时不变注意力图。并且由于其当中使用了共线参数,比一般的深度神经网络时序模型的参数量降低到了1%左右,并且对模型有较好的解释性。总结来看,在1块1080ti跑完了所有模型,确实很有亲切感。
具体结构中:
(1)使用深度卷积层和浅的全连接层分别对每个序列提取模式。(这里应该是共享了权重)
(2)结合注意力机制,从前面的序列模式中生成注意力图(序列模式可直接输入,也可考虑经过embedding再输入)
最后把序列模式ui以及经过注意力机制提取的vi链接在一起,并通过全连接层产生最终输出
Abstract:
Given a multivariate time series, how can we forecast all of its variables efficiently and accurately? The multivariate forecasting, which is to predict the future observations of a multivariate time …
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Given a multivariate time series, how can we forecast all of its variables efficiently and accurately? The multivariate forecasting, which is to predict the future observations of a multivariate time series, is a fundamental problem closely related to many real-world applications. However, previous multivariate models suffer from large model sizes due to the inefficiency of capturing complex intra-variable patterns and inter-variable correlations, resulting in poor accuracy. In this work, we propose AttnAR (attention-based autoregression), a novel approach for general multivariate forecasting which maximizes its model efficiency via separable structure. AttnAR first extracts variable-wise patterns by a mixed convolution extractor that efficiently combines deep convolution layers and shallow dense layers. Then, AttnAR aggregates the patterns by learning time-invariant attention maps between the target variables. AttnAR accomplishes the state-of-the-art forecasting accuracy in four datasets with up to 117.3 times fewer parameters than the best competitors.
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795.
张浩彬
(2022-08-10 22:51):
#paper 10.1609/aaai.v34i04.6056
在现实中,具备缺失值的时序很常见。在预测中,我们往往借助缺失位置的局部信息,或者全局均值等方式对缺失值进行插补在进行预测。但是对于缺失率较高,或存在连续缺失的情况,这些方法就可能不够了。本文提出了称为Lgnet的网络结构,在基于LSTM的基础上,对于多时间序列预测问题,借助其他序列的信息,对于序列的缺失值构建基于局部和全局的插补,并且结合gan增强对全局的估计
局部特征构造:经验均值和距离该值往后最近的一点
全局特征:对整体序列进行模式的识别(模式的数量是一个超参数),然后利用局部特征作为索引,找到相似的序列模式,并进行加权构造
以数据点的局部特征作为索引
最后对缺失值的估计有,由4部分取平均:经验均值,最近值,LSTM原始网络的预测值以及全局特征。另外,本文引入gan增强对输出的预测。
最后的实验来看:(1)Lgnet能够提高预测准确率;(2)对数据缺失率进行实验,Lgnet对缺失比例有比较强的鲁棒性。
消融实验:(1)基于内存模块所构造的全局特征,对数据确实的鲁棒性有比较重要的影响;(2)加入gan,能够提高2%-10%的预测精度,尤其是对缺失较高的数据集来说,引入gan更有利于捕捉全局的数据分布
Abstract:
Multivariate time series (MTS) forecasting is widely used in various domains, such as meteorology and traffic. Due to limitations on data collection, transmission, and storage, real-world MTS data usually contains …
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Multivariate time series (MTS) forecasting is widely used in various domains, such as meteorology and traffic. Due to limitations on data collection, transmission, and storage, real-world MTS data usually contains missing values, making it infeasible to apply existing MTS forecasting models such as linear regression and recurrent neural networks. Though many efforts have been devoted to this problem, most of them solely rely on local dependencies for imputing missing values, which ignores global temporal dynamics. Local dependencies/patterns would become less useful when the missing ratio is high, or the data have consecutive missing values; while exploring global patterns can alleviate such problem. Thus, jointly modeling local and global temporal dynamics is very promising for MTS forecasting with missing values. However, work in this direction is rather limited. Therefore, we study a novel problem of MTS forecasting with missing values by jointly exploring local and global temporal dynamics. We propose a new framework øurs, which leverages memory network to explore global patterns given estimations from local perspectives. We further introduce adversarial training to enhance the modeling of global temporal distribution. Experimental results on real-world datasets show the effectiveness of øurs for MTS forecasting with missing values and its robustness under various missing ratios.
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796.
张德祥
(2022-08-10 18:02):
#paper https://doi.org/10.1098/rsos.220226 An insula hierarchical network architecture for active interoceptive inference 具身智能,如何具身呢?人类对自身是如何调控的?大脑由维持生存功能的内脏器官组成,包括胃肠、心血管、呼吸、体温调节、激素和免疫系统;
根据主动推理理论,大脑使用通过经验或心理模拟获得的内部生成模型,不断生成对预期感官数据的递减或自上而下的预测.在主动推理中,代理的目标是找到最优的动作策略,例如在给定的环境中快速选择动作、肌肉激活模式、决策和社会行为的规则或策略,其最小化由代理与环境的交互或采样产生的预测和实际感觉输入之间的自由能或预测误差,例如在家或在公共场合的社会交互的质量,驾驶或行走时的街道导航,健康食物的选择, 学习演奏乐器,打篮球时运球还是传球,婴儿学习在光滑或粗糙的表面上行走。
将主动推断和同种异体异位的概念统一在主动内感受推断的范围内,以表明大脑还创建和存储身体内部环境的生成内感受模型,并使用这种内感受模型来解释上升的内感受信号,并生成下降的内感受预测,以调节和实现内脏器官和生理过程的期望状态,例如心率、激素释放、免疫系统的激活和能量代谢。
心血管调节研究已经可靠地证明,人类可以主动学习提高或降低心率和血压。对人类和动物的其他研究也观察到了对内脏反应的预期和自愿控制,包括心率、血压、血容量、呼吸、胃肠功能、肠道控制、瞳孔扩张、皮肤电活动、体温、免疫抑制和血氧水平.总的来说,这些心理生理学研究表明,内脏反应的学习,至少对于那些人类可以施加自愿控制的反应,可能遵循在运动行为中观察到的类似适应原则,例如行为控制中的学习和变化阶段、先验知识的影响、学习或概括的转移、反馈的效率、效应器特异性和对所学内脏反应的认识.
论文图片展示了1 交感和副交感神经系统的组织结构图,2 岛叶上行内感受性通路图 3 主动内感受性推理的岛叶、前额叶皮质和纹状体平行网络层级图。
Abstract:
In the brain, the insular cortex receives a vast amount of interoceptive information, ascending through deep brain structures, from multiple visceral organs. The unique hierarchical and modular architecture of the …
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In the brain, the insular cortex receives a vast amount of interoceptive information, ascending through deep brain structures, from multiple visceral organs. The unique hierarchical and modular architecture of the insula suggests specialization for processing interoceptive afferents. Yet, the biological significance of the insula's neuroanatomical architecture, in relation to deep brain structures, remains obscure. In this opinion piece, we propose the Insula Hierarchical Modular Adaptive Interoception Control (IMAC) model to suggest that insula modules (granular, dysgranular and agranular), forming parallel networks with the prefrontal cortex and striatum, are specialized to form higher order interoceptive representations. These interoceptive representations are recruited in a context-dependent manner to support habitual, model-based and exploratory control of visceral organs and physiological processes. We discuss how insula interoceptive representations may give rise to conscious feelings that best explain lower order deep brain interoceptive representations, and how the insula may serve to defend the body and mind against pathological depression.
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797.
王昊
(2022-08-10 11:27):
#paper 10.48550/arXiv.2109.07872 TAN S, GE M, GUO D, 等. Knowledge-based Embodied Question Answering[J/OL]. 2021[2022-08-09]. https://arxiv.org/abs/2109.07872v1.清华孙富春组的文章,主要介绍具身智能体在AI2thor空间里回答针对周围环境的问题,且这些问题需要外部知识库的支持才能回答.
之前存在的问题:具身问答(EQA)不具备回答需要外部知识图谱的问题的能力(其实在KBVQA领域已经有人这么做过了),且不具备推理能力(其实什么可以被定义为推理挺难说的),多跳问答是一个较难的问题.,且现在的EQA系统不能使用遗忘的记忆来节省智能体重新探索的时间.
本文贡献:
1.提出了knowledge-EQA的任务,基于AI2THOR虚拟环境;
2.建立了数据集(数据集的种类只有一些很简单的问题,不是很难)
3.提出了基于 神经编程诊断、3D场景图、3D重建、问题转换为SQL语句、蒙特卡洛树搜索 等技术综合起来的方法来解决上述问题。
arXiv,
2021.
DOI: 10.48550/arXiv.2109.07872
Abstract:
In this paper, we propose a novel Knowledge-based Embodied Question Answering (K-EQA) task, in which the agent intelligently explores the environment to answer various questions with the knowledge. Different from …
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In this paper, we propose a novel Knowledge-based Embodied Question Answering (K-EQA) task, in which the agent intelligently explores the environment to answer various questions with the knowledge. Different from explicitly specifying the target object in the question as existing EQA work, the agent can resort to external knowledge to understand more complicated question such as "Please tell me what are objects used to cut food in the room?", in which the agent must know the knowledge such as "knife is used for cutting food". To address this K-EQA problem, a novel framework based on neural program synthesis reasoning is proposed, where the joint reasoning of the external knowledge and 3D scene graph is performed to realize navigation and question answering. Especially, the 3D scene graph can provide the memory to store the visual information of visited scenes, which significantly improves the efficiency for the multi-turn question answering. Experimental results have demonstrated that the proposed framework is capable of answering more complicated and realistic questions in the embodied environment. The proposed method is also applicable to multi-agent scenarios.
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798.
张浩彬
(2022-08-09 17:26):
#paper 10.48550/arXiv.2203.03423
Multivariate Time Series Forecasting with Latent Graph Inference 2022的文章。我觉得比较有意思的是,我感觉作者是把简单的东西套在了一个高级的框架里面(这种写作思路值得学习)文章把多变量预测问题分成了两个路线,一个是全局单变量建模(变量共享),一个是直接全局建模全局预测。而作者说他的办法是在第一个方法的基础上进行模块化扩展。具体来说,就是每个单独序列输入编码器生成隐变量。隐变量三会进入一图结构中然后得到隐变量的预测输出。再将输出解码得到最终输出。然后作者说中间的图结构,我们有两种方式,一种是全连接图网络(FC-GNN),一种是二分法图网络(BP-GNN)(我理解是GNN中聚类的一种变体,至于多少类别,则是一个超参数)。这种思路,显然效率会有很大的提升,即使是作者提到的全局GNN,因为只是对隐变量作图,效率也是有提升,更不要说通过抽样构造子图了。所以比起基线模型效率最高,完全可以理解。倒是在准确率的讨论上,实际上作者提出的网络也不全是最优的(两个数据集,一个大部分最优,另一个不是)。虽然做了个简单的消融实验,但是作者也没怎么解释。
总结下来几点:
(1)往上套一个大框架:多变量预测分成两种;embedding变成隐变量;图模型中提供了全连接+二分图的性能-效率权衡()
(2)实验不够,加模拟(这一点还真类似统计中oracle性质的讨论,貌似在深度学习的会议中相对少见)
arXiv,
2022.
DOI: 10.48550/arXiv.2203.03423
Abstract:
This paper introduces a new approach for Multivariate Time Series forecasting that jointly infers and leverages relations among time series. Its modularity allows it to be integrated with current univariate …
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This paper introduces a new approach for Multivariate Time Series forecasting that jointly infers and leverages relations among time series. Its modularity allows it to be integrated with current univariate methods. Our approach allows to trade-off accuracy and computational efficiency gradually via offering on one extreme inference of a potentially fully-connected graph or on another extreme a bipartite graph. In the potentially fully-connected case we consider all pair-wise interactions among time-series which yields the best forecasting accuracy. Conversely, the bipartite case leverages the dependency structure by inter-communicating the N time series through a small set of K auxiliary nodes that we introduce. This reduces the time and memory complexity w.r.t. previous graph inference methods from O(N^2) to O(NK) with a small trade-off in accuracy. We demonstrate the effectiveness of our model in a variety of datasets where both of its variants perform better or very competitively to previous graph inference methods in terms of forecasting accuracy and time efficiency.
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799.
张浩彬
(2022-08-09 15:58):
#paper 10.1145/3394486.3403118
Connecting the Dots_Multivariate Time Series Forecasting with Graph Neural Networks:
KDD2020的文章,感觉最大创新就是可以自适应创建图-但是细读下来又感觉乏善可陈;总的来说,感觉是把时空一套的东西套到了多时间序列中。最后也证明了,这套框架虽然可以用于多序列问题,但是还是时空效果最好,这也是不难理解、
本文提出了交MTGNN的基于图神经网络的模型来处理多序列的预测问题。本文认为多序列预测主要解决两个问题,分别是(1)怎么自适应生成图;(2)怎么在训练中根性图。
挑战1:图结构需要学习;通过3个核心组件解决:(1)图学习层:基于数据自适应提取稀疏图邻接矩阵(2)图卷积层:解决变量间的空间以来关系,转为有向图设计,避免图卷积网络的过渡平滑;(3)时间卷积层:通过一维卷积捕获时间模式--可以发现多个时间模式以及长时间网络
挑战2:训练中不仅参数需要更新,图结构也需要更新(要在端到端学习中完成这个过程):curriculum learning
回到模型的结构中:
1.大结构:
(1)图学习层计算邻接矩阵。
(2)输入数据首先通过1*1卷积核到时间卷积,再到图卷积(图卷积实际山接受三个输入:图学习层,上一层时间卷积的输出,以及时间卷积前解一个残差链接快),实际上一组操作包括了一个时间卷积核图卷积。经过n次操作。每次操作都会产生一个输出,把每次操作的输出连接在一起。时间卷积就是在序列维度处理数据,图卷积就是在图维度处理数据。
2.具体组件
(1)图学习层-通过抽样分组方法计算节点间关系,避免内存溢出-并通过一种新的度量方式确定单向距离(单向网络)
(2)图卷积层-似乎有点类似gru一样提取上层信息-成为“ 混合跳传播层”
(3)时间卷积模块-一维空洞卷积-inception--1*2 ,1*3,1*6,1*7,用这些卷积来覆盖7,12,24,28.60这样的时间周期--用扩张卷积来加大感受野使得可以提取长时间的特征
对比了几个主流结构,都取得了不错的结果。并进行了消融实验验证。消融实验验证:图卷积模块,mix-hop链接,inception,curriculum learning;并单独额外研究了图学习层。
Abstract:
Modeling multivariate time series has long been a subject that has attracted researchers from a diverse range of fields including economics, finance, and traffic. A basic assumption behind multivariate time …
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Modeling multivariate time series has long been a subject that has attracted researchers from a diverse range of fields including economics, finance, and traffic. A basic assumption behind multivariate time series forecasting is that its variables depend on one another but, upon looking closely, it is fair to say that existing methods fail to fully exploit latent spatial dependencies between pairs of variables. In recent years, meanwhile, graph neural networks (GNNs) have shown high capability in handling relational dependencies. GNNs require well-defined graph structures for information propagation which means they cannot be applied directly for multivariate time series where the dependencies are not known in advance. In this paper, we propose a general graph neural network framework designed specifically for multivariate time series data. Our approach automatically extracts the uni-directed relations among variables through a graph learning module, into which external knowledge like variable attributes can be easily integrated. A novel mix-hop propagation layer and a dilated inception layer are further proposed to capture the spatial and temporal dependencies within the time series. The graph learning, graph convolution, and temporal convolution modules are jointly learned in an end-to-end framework. Experimental results show that our proposed model outperforms the state-of-the-art baseline methods on 3 of 4 benchmark datasets and achieves on-par performance with other approaches on two traffic datasets which provide extra structural information.
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800.
张德祥
(2022-08-09 15:11):
#paper https://doi.org/10.1162%2Fneco_a_01341 Deeply Felt Affect: The Emergence of Valence in Deep Active Inference 智能从模式识别,识别后的第二阶是模型对自我模型识别的信心-confidence,第三阶还可以对自我信心的信心,这种自下而上及自上而下才是真正的层级模型,hierarchical model;另外一种层级模型是 从训练角度看,1监督训练无智能,2动作行动闭环环境有反馈,3增加时间维度的长时反馈,4再一个层次是基于经验的行动信念的自上而下指导,5还可以继续有信念的信念; 6推理的时候也可以按照信念的强度进行推理。另外文章中的图表展示非常棒
Abstract:
The positive-negative axis of emotional valence has long been recognized as fundamental to adaptive behavior, but its origin and underlying function have largely eluded formal theorizing and computational modeling. Using …
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The positive-negative axis of emotional valence has long been recognized as fundamental to adaptive behavior, but its origin and underlying function have largely eluded formal theorizing and computational modeling. Using deep active inference, a hierarchical inference scheme that rests on inverting a model of how sensory data are generated, we develop a principled Bayesian model of emotional valence. This formulation asserts that agents infer their valence state based on the expected precision of their action model-an internal estimate of overall model fitness ("subjective fitness"). This index of subjective fitness can be estimated within any environment and exploits the domain generality of second-order beliefs (beliefs about beliefs). We show how maintaining internal valence representations allows the ensuing affective agent to optimize confidence in action selection preemptively. Valence representations can in turn be optimized by leveraging the (Bayes-optimal) updating term for subjective fitness, which we label affective charge (AC). AC tracks changes in fitness estimates and lends a sign to otherwise unsigned divergences between predictions and outcomes. We simulate the resulting affective inference by subjecting an in silico affective agent to a T-maze paradigm requiring context learning, followed by context reversal. This formulation of affective inference offers a principled account of the link between affect, (mental) action, and implicit metacognition. It characterizes how a deep biological system can infer its affective state and reduce uncertainty about such inferences through internal action (i.e., top-down modulation of priors that underwrite confidence). Thus, we demonstrate the potential of active inference to provide a formal and computationally tractable account of affect. Our demonstration of the face validity and potential utility of this formulation represents the first step within a larger research program. Next, this model can be leveraged to test the hypothesized role of valence by fitting the model to behavioral and neuronal responses.
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