新型冠状病毒肺炎在不同社区传播的 SIR 模型假设 | 网络科学论文速递30篇-集智俱乐部


本文由机器翻译,仅供参考,感兴趣请查阅论文原文

核心速递


  • 新型冠状病毒肺炎在不同社区传播的 SIR 模型假设

  • 传染病在随机图上的蔓延: 新型冠状病毒肺炎的逾渗型模型

  • 弱的可积性破坏:相干扩散中具有可积性特征的混

  • 固态合成中前体的相似性(从科学文献中提取)

  • 一个改进的流行病学模型来理解新型冠状病毒肺炎对脆弱个体的不均衡影响以及帮助他们摆脱封锁所需的方法

  • 社交媒体实时攻击性检测

  • 利用情感信息预先检测在线会话中的有毒评论

  • 子图神经网

  • 一种基于命名行为建模的多视图中文用户账户跨网络对齐方法

  • 基于 QUBO 和数字退火的市场图聚

  • 社会网络等价关系的统一框架

  • 社会距离干预的健康和经济效应: 一个个体为本模型的新型冠状病毒肺炎流行病模拟

  • 适应性交通政策对城市环境中新型冠状病毒肺炎传播的影响: 韩国首尔的干预分析

  • 在印度,红灯区延长关闭对新型冠状病毒肺炎传播的影响

  • 系统性风险的网络敏感性

  • 病毒传播分析: 随机流行病学模型的转移模型表示

  • 专家对物理论文的渐进式作业中估计干扰程度的几个指标的趋同效度

  • 科学与算法的非中立性: 基础物理与社会之间的机器学

  • 通过 Twitter 评估美国城市公园的幸福感

  • 模拟填料和裂化

  • 新型冠状病毒肺炎流感大流行期间室内层面非药物干预建模: 基于行人动力学的微观模拟方法

  • 未来美国电网的异功能图弹性

  • 21新型冠状病毒肺炎非洲的冲突: 社会距离、粮食脆弱性和福利反应

  • 振动和噪声作用下捕光复合体的多尺度循环动力学

  • 通过微血管分叉实现细胞血液纳米粒子的异质分配

  • 组织病理学和高幅超声中单泡动力学的建模与验证

  • 包括根茎生长在内的植被模式的一般模型

  • 运动蛋白质通过微管交叉转运的随机模拟

  • 减少  SARS-COV-2和其他病毒对 spike 蛋白渗透的有效途径: 通过表面粒子静电荷协商

  • 喷气火车在通话中产生远程湍流喷气式传输,可能与无症状病毒传播有关





新型冠状病毒肺炎在

不同社区传播的 SIR 模型假设


原文标题:

A SIR model assumption for the spread of COVID-19 in different communities

地址:

http://arxiv.org/abs/2006.10651

作者:

Ian Cooper,Argha Mondal,Chris G. Antonopoulos


Abstract:In this paper, we study the effectiveness of the modelling approach on the pandemic due to the spreading of the novel COVID-19 disease and develop a susceptible-infected-removed (SIR) model that provides a theoretical framework to investigate its spread within a community. Here, the model is based upon the well-known susceptible-infected-removed (SIR) model with the difference that a total population is not defined or kept constant per se and the number of susceptible individuals does not decline monotonically. To the contrary, as we show herein, it can be increased in surge periods! In particular, we investigate the time evolution of different populations and monitor diverse significant parameters for the spread of the disease in various communities, represented by countries and the state of Texas in the USA. The SIR model can provide us with insights and predictions of the spread of the virus in communities that the recorded data alone cannot. Our work shows the importance of modelling the spread of COVID-19 by the SIR model that we propose here, as it can help to assess the impact of the disease by offering valuable predictions. Our analysis takes into account data from January to June, 2020, the period that contains the data before and during the implementation of strict and control measures. We propose predictions on various parameters related to the spread of COVID-19 and on the number of susceptible, infected and removed populations until September 2020. By comparing the recorded data with the data from our modelling approaches, we deduce that the spread of COVID-19 can be under control in all communities considered, if proper restrictions and strong policies are implemented to control the infection rates early from the spread of the disease.

摘要:在这篇论文中,我们研究了由于新型新型冠状病毒肺炎的传播而引起的大流行的模型方法的有效性,并发展了一个易感-感染-移除(SIR)模型,该模型提供了一个理论框架来调查它在社区内的传播。该模型基于已知的易感-感染-移除(SIR)模型,其差异在于总种群不确定或自身保持不变,易感个体的数量不单调下降。相反,正如我们在这里所展示的,它可以在高峰期增加!特别是,我们调查不同人口的时间演变和监测不同的重要参数的疾病在各个社区的传播,代表国家和德克萨斯州在美国。Sir 模型可以为我们提供关于病毒在社区传播的洞察力和预测力,而仅仅记录数据是无法做到的。我们的工作表明了我们在这里提出的 SIR 模型模拟新型冠状病毒肺炎传播的重要性,因为它可以通过提供有价值的预测来帮助评估疾病的影响。我们的分析考虑了2020年1月至6月的数据,这一时期包含了在实施严格控制措施之前和期间的数据。我们建议预测与新型冠状病毒肺炎传播相关的各种参数,以及到2020年9月为止的易感、感染和移除种群的数量。通过比较记录的数据和我们的模型方法得出的数据,我们推断,如果实施适当的限制和强有力的政策,从疾病传播的早期控制感染率,那么在所有考虑到的社区中,新型冠状病毒肺炎的传播可以得到控制



传染病在随机图上的蔓延: 

新型冠状病毒肺炎的逾渗型模型


原文标题:

Spreading of infections on random graphs: A percolation-type model for COVID-19

地址:

https://arxiv.org/abs/2006.10490

作者:

Fabrizio Croccolo,H. Eduardo Roman


Abstract:We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and behavior of the lattice model, implemented using the same lockdown scheme as for the SIR scheme, are discussed in detail and illustrated with extensive simulations. A comparison between both models is presented for the case of COVID-19 data from the USA. Both fits to the empirical data are very good, but some differences emerge between the two approaches which indicate the usefulness of having an alternative approach to the widespread SIR model.

摘要:利用逾渗理论中的概念,在网络上建立了一个传染病传播模型。该模型的动机是讨论标准的 SIR 模型,并扩展描述封锁在群体中的影响。详细讨论了格模型的基本思想和行为,使用与 SIR 方案相同的封锁方案实现,并用大量的仿真进行了说明。本文以美国新型冠状病毒肺炎数据为例,对两种模型进行了比较。这两种方法都非常符合经验数据,但两种方法之间出现了一些差异,这表明对广泛使用的 SIR 模型采用替代方法是有用的



弱的可积性破坏:

相干扩散中具有可积性特征的混沌

原文标题:

Weak integrability breaking: chaos with integrability signature in coherent diffusion

地址:

https://arxiv.org/abs/2006.09793

作者:

Marko Znidaric


Abstract:We study how perturbations affect dynamics of an integrable many-body quantum system. Looking at spin transport in the Heisenberg chain with impurities, we find that in the thermodynamic limit transport gets diffusive already at an infinitesimal perturbation. Small extensive perturbations therefore cause an immediate transition from integrability to chaos. Nevertheless, there is a remnant of integrability encoded in the dependence of diffusion constant on the impurity density. At small densities it is proportional to the square root of the density, instead of to the density as would follow from Matthiessen's rule. Results also highlight nontrivial interacting scattering on a single impurity.

摘要:研究了微扰对可积多体系统动力学行为的影响。观察带有杂质的海森堡链中的自旋输运,我们发现在热力学极限中,输运在无穷小的扰动下已经扩散了。因此,微小而广泛的扰动会立即引起从可积到混沌的过渡。然而,在扩散常数对杂质密度的依赖性中存在可积编码的残余。在较小的密度下,它与密度的平方根成正比,而不是像按照马泰森定律那样与密度成正比。结果还突出了单个杂质上的非平凡相互作用散射



固态合成中前体的相似性

(从科学文献中提取)


原文标题:

Similarity of Precursors in Solid-state Synthesis as Text-Mined from Scientific Literature

地址:

https://arxiv.org/abs/2006.10315

作者:

Tanjin He,Wenhao Sun,Haoyan Huo,Olga Kononova,Ziqin Rong,Vahe Tshitoyan,Tiago Botari,Gerbrand Ceder


Abstract:Collecting and analyzing the vast amount of information available in the solid-state chemistry literature may accelerate our understanding of materials synthesis. However, one major problem is the difficulty of identifying which materials from a synthesis paragraph are precursors or are target materials. In this study, we developed a two-step Chemical Named Entity Recognition (CNER) model to identify precursors and targets, based on information from the context around material entities. Using the extracted data, we conducted a meta-analysis to study the similarities and differences between precursors in the context of solid-state synthesis. To quantify precursor similarity, we built a substitution model to calculate the viability of substituting one precursor with another while retaining the target. From a hierarchical clustering of the precursors, we demonstrate that "chemical similarity" of precursors can be extracted from text data. Quantifying the similarity of precursors helps provide a foundation for suggesting candidate reactants in a predictive synthesis model.

摘要:收集和分析固体化学文献中的大量信息可以加快我们对材料合成的理解。然而,一个主要问题是难以确定合成段落中的哪些材料是前体或目标材料。在这项研究中,我们开发了一个两步的化学命名实体识别(CNER)模型来识别前体和目标,基于信息从周围的物质实体。利用提取的数据,我们进行了元分析,以研究在固态合成的背景下前体之间的异同。为了量化前体相似性,我们建立了一个替代模型来计算一个前体与另一个前体替代的生存能力,同时保留目标。从前体的层次聚类,我们演示了前体的“化学相似性”可以从文本数据中提取。量化前体物的相似性有助于在预测合成模型中建立候选反应物



一个改进的流行病学模型来

理解新型冠状病毒肺炎对脆弱个体

的不均衡影响以及

帮助他们摆脱封锁所需的方法


原文标题:

A Modified Epidemiological Model to Understand the Uneven Impact of COVID-19 on Vulnerable Individuals and the Approaches Required to Help them Emerge from Lockdown

地址:

http://arxiv.org/abs/2006.10495

作者:

Dario Ortega Anderez,Eiman Kanjo,Ganna Pogrebna,Shane Johnson,John Alan Hunt


Abstract:COVID-19 has shown a relatively low mortality rate in young healthy individuals, with the majority of this group being asymptomatic or having mild symptoms, while the severity of the disease among individuals with underlying health conditions has caused signiffcant mortality rates worldwide. Understanding these differences in mortality amongst different sectors of society and modelling this will enable the different levels of risk and vulnerabilities to be determined to enable strategies exit the lockdown. However, epidemiological models do not account for the variability encountered in the severity of the SARS-CoV-2 disease across different population groups. To overcome this limitation, it is proposed that a modiffed SEIR model, namely SEIR-v, through which the population is separated into two groups regarding their vulnerability to SARS-CoV-2 is applied. This enables the analysis of the spread of the epidemic when different contention measures are applied to different groups in society regarding their vulnerability to the disease. A Monte Carlo simulation indicates a large number of deaths could be avoided by slightly decreasing the exposure of vulnerable groups to the disease. From this modelling a number of mechanisms can be proposed to limit the exposure of vulnerable individuals to the disease in order to reduce the mortality rate among this group. One option could be the provision of a wristband to vulnerable people and those without a contact-tracing app. By combining very dense contact tracing data from smartphone apps and wristband signals with information about infection status and symptoms, vulnerable people can be protected and kept safer. Widespread utilisation would extend the protection further beyond these high risk groups.

摘要:新型冠状病毒肺炎显示,健康年轻人的死亡率相对较低,其中大多数人没有症状或症状轻微,而具有潜在健康状况的个人的疾病严重程度已导致全球死亡率显著上升。了解社会不同部门之间死亡率的这些差异并建立模型,将有助于确定不同程度的风险和脆弱性,从而使各项战略得以脱离封锁状态。然而,流行病学模型没有考虑到不同人群群体中 SARS-CoV-2疾病严重程度的变异性。为了克服这一局限性,提出了一种改进的 SEIR 模型,即 SEIR-v 模型,通过该模型将种群按照对 sars cov-2的易感性分为两组。这使我们能够分析在社会上不同群体对疾病的脆弱性采取不同的争论措施时,流行病的传播情况。蒙特卡罗模拟表明,稍微减少易感人群对疾病的接触可以避免大量的死亡。通过这种建模,可以提出一些机制,限制易受伤害的个人接触这种疾病,以降低这一群体的死亡率。其中一个选择可能是向弱势群体和那些没有联系人追踪应用程序的人提供腕带。通过将来自智能手机应用程序和腕带信号的密集接触追踪数据与感染状况和症状的信息结合起来,脆弱的人群可以得到保护,并且更加安全。广泛的利用将使保护范围进一步扩大到这些高风险群体之外



社交媒体实时攻击性检测


原文标题:

Catching them red-handed: Real-time Aggression Detection on Social Media

地址:

http://arxiv.org/abs/2006.10104

者:

Herodotos Herodotou,Despoina Chatzakou,Nicolas Kourtellis


Abstract:The rise of online aggression on social media is evolving into a major point of concern. Several machine and deep learning approaches have been proposed recently for detecting various types of aggressive behavior. However, social media are fast paced, generating an increasing amount of content, while aggressive behavior evolves over time. In this work, we introduce the first practical, real-time framework for detecting aggression on Twitter via embracing the streaming machine learning paradigm. Our method adapts its ML classifiers in an incremental fashion as it receives new annotated examples and is able to achieve the same (or even higher) performance as batch-based ML models, with over 90% accuracy, precision, and recall. At the same time, our experimental analysis on real Twitter data reveals how our framework can easily scale to accommodate the entire Twitter Firehose (of 778 million tweets per day) with only 3 commodity machines. Finally, we show that our framework is general enough to detect other related behaviors such as sarcasm, racism, and sexism in real time.

摘要:社交媒体上网络攻击行为的增加正在演变成一个主要的关注点。一些机器和深度学习的方法最近被提出来检测各种类型的攻击性行为。然而,社交媒体是快节奏的,产生了越来越多的内容,而攻击性行为随着时间的推移而发展。在这项工作中,我们介绍了第一个实用的、实时的框架,通过采用流式机器学习范式来检测 Twitter 上的攻击行为。我们的方法在接收新的注释示例时,以增量的方式调整其机器学习分类器,并且能够获得与基于批处理的机器学习模型相同(甚至更高)的性能,准确率、精确度和召回率超过90% 。与此同时,我们对真实 Twitter 数据的实验分析揭示了我们的框架如何能够轻松地扩展以适应整个 Twitter Firehose (每天7.78亿条 tweet) ,而只需要3台普通机器。最后,我们展示了我们的框架足够通用,可以实时检测其他相关行为,如讽刺、种族歧视和性别歧视



利用情感信息预先

检测在线会话中的有毒评论


原文标题

Using Sentiment Information for Preemptive Detection of Toxic Comments in Online Conversations

地址:

https://arxiv.org/abs/2006.10145

作者:

Éloi Brassard-Gourdeau,Richard Khoury


Abstract:The challenge of automatic detection of toxic comments online has been the subject of a lot of research recently, but the focus has been mostly on detecting it in individual messages after they have been posted. Some authors have tried to predict if a conversation will derail into toxicity using the features of the first few messages. In this paper, we combine that approach with previous work on toxicity detection using sentiment information, and show how the sentiments expressed in the first messages of a conversation can help predict upcoming toxicity. Our results show that adding sentiment features does help improve the accuracy of toxicity prediction, and also allow us to make important observations on the general task of preemptive toxicity detection.

摘要:自动检测网上有毒评论的挑战最近已经成为许多研究的主题,但是重点主要是在个人信息发布后检测它们。一些作者试图通过前几条信息的特征来预测一段对话是否会脱离正常轨道。在这篇论文中,我们将这种方法与之前利用情感信息进行毒性检测的工作结合起来,并展示了在一次谈话的第一条信息中表达的情感如何帮助预测即将到来的毒性。我们的结果表明,增加情感特征确实有助于提高毒性预测的准确性,也允许我们对抢先毒性检测的一般任务进行重要观察



子图神经网络


原文标题:

Subgraph Neural Networks

地址:

http://arxiv.org/abs/2006.10538

作者:

Emily Alsentzer,Samuel G. Finlayson,Michelle M. Li,Marinka Zitnik


Abstract:Deep learning methods for graphs achieve remarkable performance on many node-level and graph-level prediction tasks. However, despite the proliferation of the methods and their success, prevailing Graph Neural Networks (GNNs) neglect subgraphs, rendering subgraph prediction tasks challenging to tackle in many impactful applications. Further, subgraph prediction tasks present several unique challenges, because subgraphs can have non-trivial internal topology, but also carry a notion of position and external connectivity information relative to the underlying graph in which they exist. Here, we introduce SUB-GNN, a subgraph neural network to learn disentangled subgraph representations. In particular, we propose a novel subgraph routing mechanism that propagates neural messages between the subgraph's components and randomly sampled anchor patches from the underlying graph, yielding highly accurate subgraph representations. SUB-GNN specifies three channels, each designed to capture a distinct aspect of subgraph structure, and we provide empirical evidence that the channels encode their intended properties. We design a series of new synthetic and real-world subgraph datasets. Empirical results for subgraph classification on eight datasets show that SUB-GNN achieves considerable performance gains, outperforming strong baseline methods, including node-level and graph-level GNNs, by 12.4% over the strongest baseline. SUB-GNN performs exceptionally well on challenging biomedical datasets when subgraphs have complex topology and even comprise multiple disconnected components.

摘要:图的深度学习方法在许多节点级和图级预测任务上取得了显著的效果。然而,尽管这些方法不断涌现并取得了成功,但是当前流行的图神经网络忽略了子图,使得子图预测在许多有影响的应用中具有挑战性。此外,子图预测任务提出了几个独特的挑战,因为子图可以有非平凡的内部拓扑结构,但也携带位置和相对于它们所在的底层图的外部连接信息的概念。在这里,我们介绍了 SUB-GNN,一个子图神经网络学习解纠缠子图表示。特别地,我们提出了一种新的子图路由机制,在子图的组件之间传播神经信息,并从下面的图中随机采样锚定块,从而产生高度精确的子图表示。指定了3个通道,每个通道的设计都是为了捕捉子图结构的不同方面,我们提供了通道编码其预期属性的经验证明。我们设计了一系列新的合成的和真实世界的子图数据集。对8个数据集子图分类的实证结果表明,SUB-GNN 在最强基线上的性能提高可观,优于强基线方法,包括节点级和图级 gnn,提高了12.4% 。当子图具有复杂的拓扑结构,甚至包含多个不连接的组件时,SUB-GNN 在挑战生物医学数据集方面表现出色



一种基于命名行为建模的

多视图中文用户账户跨网络对齐方法


原文标题:

A Multi-View Approach Based on Naming Behavioral Modeling for Aligning Chinese User Accounts across Multiple Networks

地址:

https://arxiv.org/abs/2006.10633

作者:

Junxing Zhu,Xiang Wang,Qiang Liu,Xiaoyong Li,Chengcheng Shao,Bin Zhou


Abstract:Hundreds of millions of Chinese people have become social network users in recent years, and aligning the accounts of common Chinese users across multiple social networks is valuable to many inter-network applications, e.g., cross-network recommendation, cross-network link prediction. Many methods have explored the proper ways of utilizing account name information into aligning the common English users' accounts. However, how to properly utilize the account name information when aligning the Chinese user accounts remains to be detailedly studied. In this paper, we firstly discuss the available naming behavioral models as well as the related features for different types of Chinese account name matchings. Secondly, we propose the framework of Multi-View Cross-Network User Alignment (MCUA) method, which uses a multi-view framework to creatively integrate different models to deal with different types of Chinese account name matchings, and can consider all of the studied features when aligning the Chinese user accounts. Finally, we conduct experiments to prove that MCUA can outperform many existing methods on aligning Chinese user accounts between Sina Weibo and Twitter. Besides, we also study the best learning models and the top-k valuable features of different types of name matchings for MCUA over our experimental data sets.

摘要:近年来,数以亿计的中国人已经成为社交网络用户,将中国普通用户的账户跨越多个社交网络对许多跨网络应用(如跨网络推荐、跨网络链接预测)是有价值的。许多方法已经探索了利用账户名称信息对齐普通英语用户账户的正确方法。然而,如何在中文用户账户对齐时正确地利用账户名信息,还有待于进一步研究。本文首先讨论了不同类型的中文账户名称匹配的命名行为模型及其相关特征。其次,提出了多视角跨网络用户对齐方法框架,该方法利用多视角框架创造性地整合不同模型,处理不同类型的中文账户名匹配,并在对齐中文账户时考虑所有研究特征。最后,我们通过实验证明了 MCUA 能够比现有的许多方法更好地在新浪微博和 Twitter 之间调整中国用户账户。此外,我们还在实验数据集上研究了不同类型名称匹配的最佳学习模型和最有价值的特征



基于 QUBO 和数字退火的市场图聚类


原文标题:

Market Graph Clustering Via QUBO and Digital Annealing

地址:

http://arxiv.org/abs/2006.10716

作者:

Seo Hong,Pierre Miasnikof,Roy Kwon,Yuri Lawryshyn


Abstract:Our goal is to find representative nodes of a market graph that best replicate the returns of a broader market graph (index), a common task in the financial industry. We model our reference index as a market graph and express the index tracking problem in a quadratic K-medoids form. We take advantage of a purpose built hardware architecture, the Fujitsu Digital Annealer, to circumvent the NP-hard nature of the problem and solve our formulation efficiently. In this article, we combine three separate areas of the literature, market graph models, K-medoid clustering and quadratic binary optimization modeling, to formulate the index-tracking problem as a quadratic K-medoid graph-clustering problem. Our initial results show we accurately replicate the returns of a broad market index, using only a small subset of its constituent assets. Moreover, our quadratic formulation allows us to take advantage of recent hardware advances, to overcome the NP-hard nature of the problem.

摘要:我们的目标是找到市场图表的代表性节点,以最好地复制更广泛的市场图表(指数)的回报,这是金融业的一项常见任务。我们将我们的参考指数建模为一个市场图,并将指数跟踪问题表示为二次 K-medoids 形式。我们利用专门建立的硬件架构,富士通数字退火炉,以规避问题的 np 难的性质,并解决我们的公式有效。本文结合市场图模型、 k- 中心点聚类和二次二进制优化建模三个独立的领域,将指数跟踪问题转化为二次 k- 中心点图聚类问题。我们的初步结果表明,我们准确地复制了一个广泛的市场指数的收益,只使用其组成资产的一个小子集。此外,我们的二次公式允许我们利用最新的硬件进步,来克服问题的 np 难性质



社会网络等价关系的统一框架


原文标题:

A unified framework for equivalences in social networks

地址:

http://arxiv.org/abs/2006.10733

作者:

Nina Otter,Mason A. Porter


Abstract:A key concern in network analysis is the study of social positions and roles of actors in a network. The notion of "position" refers to an equivalence class of nodes that have similar ties to other nodes, whereas a "role" is an equivalence class of compound relations that connect the same pairs of nodes. An open question in network science is whether it is possible to simultaneously perform role and positional analysis. Motivated by the principle of functoriality in category theory we propose a new method that allows to tie role and positional analysis together. We illustrate our methods on two well-studied data sets in network science.

摘要:网络分析的一个关键问题是研究社会地位和网络中行为者的角色。位置的概念指的是一个等价类的节点有相似的联系其他节点,而一个“角色”是一个复合关系的等价类,连接相同的节点对。网络科学中一个悬而未决的问题是,是否有可能同时进行角色和位置分析。基于范畴理论中的功能性原则,我们提出了一种将角色和位置分析结合起来的新方法。我们在网络科学的两个充分研究的数据集上演示了我们的方法



社会距离干预的健康和经济效应: 

一个个体为本模型的

新型冠状病毒肺炎流行病模拟


原文标题:

COVID-ABS: An Agent-Based Model of COVID-19 Epidemic to Simulate Health and Economic Effects of Social Distancing Interventions

地址:

http://arxiv.org/abs/2006.10532

作者:

Petrônio C. L. Silva,Paulo V. C. Batista,Hélder S. Lima,Marcos A. Alves,Frederico G. Guimarães,Rodrigo C. P. Silva


Abstract:The COVID-19 pandemic due to the SARS-CoV-2 coronavirus have directly impacted the public health and economy. To overcome this problem, the countries have adopted different policies for controlling the spread of the virus. This paper proposes the COVID-ABS, a new SEIR agent-based model that aims to simulate the pandemic dynamics using a society of agents emulating people, business and government. Seven different scenarios varying epidemiological and economical effects of social distance interventions were performed, which are: (1) do nothing, (2) lockdown, (3) conditional lockdown, (4) vertical isolation, (5) partial isolation, (6) use of face masks, and (7) use of face masks together with 50% of adhesion to social isolation. In the impossibility of implementing scenarios with lockdown which present the lowest number of deaths and highest impact on the economy, scenarios combining the use of face masks and partial isolation can be the more realistic for implementation in terms of social cooperation. The model can be easily extended to new societies by varying the parameters as well as allows the creating of a multitude of other scenarios.

摘要:由 SARS-CoV-2冠状病毒引起的新型冠状病毒肺炎大流行已经直接影响了公共卫生和经济。为了克服这个问题,各国采取了不同的政策来控制病毒的传播。这篇论文提出了 COVID-ABS,一个新的 SEIR 个体为本模型,旨在模拟大流行的动态使用一个代理人模仿人,商业和政府的社会。我们分别在7个不同的场景中进行了社会距离干预,这些场景分别是: (1)无所作为,(2)封闭,(3)有条件封闭,(4)垂直隔离,(5)部分隔离,(6)使用口罩,(7)使用口罩,同时对社会隔离有50% 的粘附。由于不可能执行一级防范禁闭的情况,这种情况造成的死亡人数最少,对经济的影响最大,因此,就社会合作而言,将使用面罩和部分隔离结合起来的情况可能更为现实。这个模型可以通过改变参数以及创建大量的其他场景,很容易地扩展到新的社会



适应性交通政策对城市环境中

新型冠状病毒肺炎传播的影响:

韩国首尔的干预分析


原文标题:

The effect of adaptive mobility policy to the spread of COVID-19 in urban environment: intervention analysis of Seoul, South Korea

地址:

https://arxiv.org/abs/2006.10526

作者:

Yoonjin Yoon,Soohwan Oh,Jungwoo Cho,Yuyol Shin,Seyun Kim,Namwoo Kim,Haechan Cho


Abstract:Although severe mobility restrictions are recognized as the key enabler to contain COVID-19, there has been few scientific studies to validate such approach, especially in urban context. This study analyzes mobility pattern changes in Seoul, South Korea that adopted adaptive approach toward mobility. Intervention analyses reveal that major mobility reduction did occur two weeks before the city's case peak. Such voluntary adjustments exhibit strong preference shift toward private mode from public transit. Large reductions occurred in non-essential and high-contact activities of shopping and dining, while work and Starbucks trips were less affected. The collective evaluation reveal that major changes in epidemiology, mobility and policy occurred simultaneously, with no lagging nor leading contributors. Our study demonstrates that collective understanding the mutual aspects among mobility, epidemiology and policy is essential. Incremental and flexible mobility restriction is not only possible but necessary, especially for a pandemic of extensive spatial and temporal scales.

摘要:虽然严格的机动性限制被认为是遏制新型冠状病毒肺炎的关键因素,但是很少有科学研究来验证这种方法,特别是在城市环境中。本研究分析了韩国首尔采用适应性方法的移动模式的变化。干预分析显示,主要流动性下降确实发生在城市病例高峰前两周。这种自愿的调整显示出从公共交通向私人交通方式的强烈偏好转变。非必要和高接触性的购物和用餐活动大幅减少,而工作和星巴克旅行受到的影响较小。集体评估显示,流行病学、流动性和政策的主要变化同时发生,没有落后或主要的贡献者。我们的研究表明,集体理解流动性、流行病学和政策之间的相互影响是必不可少的。增量和灵活的流动性限制不仅是可能的,而且是必要的,特别是对于广泛的空间和时间尺度的流行



在印度,红灯区延长关闭

对新型冠状病毒肺炎传播的影响


原文标题:

The effect of extended closure of red-light areas on COVID-19 transmission in India

地址:

http://arxiv.org/abs/2006.10488

作者:

Abhishek Pandey,Sudhakar V. Nuti,Pratha Sah,Chad R. Wells,Alison P. Galvani,Jeffrey P. Townsend


Abstract:The novel coronavirus disease (COVID-19) pandemic has resulted in over 200,000 cases in India. Thus far, India has implemented lockdown measures to curb disease transmission. However, commercial sex work in red-light areas (RLAs) has potential to lead to COVID-19 resurgence after lockdown. We developed a model of COVID-19 transmission in RLAs, evaluating the impact of extended RLA closure compared with RLA reopening on cases, hospitalizations, and mortality rates within the RLAs of five major Indian cities, within the cities, and across India. Closure lowered transmission at all scales. More than 90% of cumulative cases and deaths among RLA residents of Kolkata, Pune, and Nagpur could be averted by the time the epidemic would peak under a re-opening scenario. Across India, extended closure of RLAs would benefit the population at large, delaying the peak of COVID-19 cases by 8 to 23 days, and avert 32% to 60.2% of cumulative cases and 43% to 67.6% of cumulative deaths at the peak of the epidemic. Extended closure of RLAs until better prevention and treatment strategies are developed would benefit public health in India.

摘要:新型冠状病毒病(新型冠状病毒肺炎)在印度的流行已导致超过20万病例。到目前为止,印度已经实施了封锁措施来遏制疾病的传播。然而,红灯区的商业性工作有可能导致禁闭之后新型冠状病毒肺炎的死灰复燃。我们开发了一个 RLA 中新型冠状病毒肺炎传播的模型,与 RLA 重新开放相比,评估了延长 RLA 关闭对病例、住院和死亡率的影响。关闭降低了传输在所有规模。在重新开放的情况下,当疫情达到高峰时,加尔各答、浦那和那格浦尔的 RLA 居民中超过90% 的累积病例和死亡可以避免。在整个印度,延长大规模杀伤性武器的关闭期将有利于广大人口,将新型冠状病毒肺炎病例的高峰期推迟8至23天,并避免32% 至60.2% 的累积病例和43% 至67.6% 的累积死亡在疫情高峰期。在制定更好的预防和治疗战略之前,延长大规模杀伤性武器的关闭期,将有利于印度的公共卫生



系统性风险的网络敏感性


原文标题:

Network Sensitivity of Systemic Risk

地址:

http://arxiv.org/abs/1805.04325

作者:

Amanah Ramadiah,Domenico Di Gangi,D. Ruggiero Lo Sardo,Valentina Macchiati,Tuan Pham Minh,Francesco Pinotti,Mateusz Wilinski,Paolo Barucca,Giulio Cimini


Abstract:A growing body of studies on systemic risk in financial markets has emphasized the key importance of taking into consideration the complex interconnections among financial institutions. Much effort has been put in modeling the contagion dynamics of financial shocks, and to assess the resilience of specific financial markets - either using real network data, reconstruction techniques or simple toy networks. Here we address the more general problem of how shock propagation dynamics depends on the topological details of the underlying network. To this end we consider different realistic network topologies, all consistent with balance sheets information obtained from real data on financial institutions. In particular, we consider networks of varying density and with different block structures, and diversify as well in the details of the shock propagation dynamics. We confirm that the systemic risk properties of a financial network are extremely sensitive to its network features. Our results can aid in the design of regulatory policies to improve the robustness of financial markets.

摘要:越来越多的关于金融市场系统性风险的研究强调了考虑金融机构之间复杂的相互联系的关键重要性。金管局致力利用真实网络数据、重组技术或简单的玩具网络模拟金融震荡的传染动态,以及评估特定金融市场的弹性。在这里,我们处理更一般的问题如何冲击传播动力学取决于拓扑细节的基础网络。为此,我们考虑了不同的现实网络拓扑结构,它们都与从金融机构真实数据中获得的资产负债表信息一致。特别地,我们考虑了不同密度和不同块状结构的网络,以及多样化的冲击波传播动力学的细节。我们确认,金融网络的系统性风险特性对其网络特性极为敏感。我们的研究结果可以帮助设计监管政策,以提高金融市场的稳健性



病毒传播分析: 

随机流行病学模型的转移模型表


原文标题:

Analysis of Virus Propagation: A Transition Model Representation of Stochastic Epidemiological Models

地址:

http://arxiv.org/abs/2006.10265

作者:

Christian Gourieroux,Joann Jasiak


Abstract:The growing literature on the propagation of COVID-19 relies on various dynamic SIR-type models (Susceptible-Infected-Recovered) which yield model-dependent results. For transparency and ease of comparing the results, we introduce a common representation of the SIR-type stochastic epidemiological models. This representation is a discrete time transition model, which allows us to classify the epidemiological models with respect to the number of states (compartments) and their interpretation. Additionally, the transition model eliminates several limitations of the deterministic continuous time epidemiological models which are pointed out in the paper. We also show that all SIR-type models have a nonlinear (pseudo) state space representation and are easily estimable from an extended Kalman filter.

摘要:越来越多的关于新型冠状病毒肺炎传播的文献依赖于各种动态 sir- 类型的模型(易感-感染-恢复) ,这些模型产生了依赖于模型的结果。为了透明和方便比较结果,我们介绍了 sir- 型随机流行病学模型的一个共同表示。这种表示是一个离散时间转移模型,它允许我们根据状态(部分)的数目及其解释对流行病学模型进行分类。此外,转移模型消除了本文指出的确定性连续时间流行病学模型的几个局限性。我们还证明了所有 sir- 型模型都具有非线性(伪)状态空间,并且很容易从扩展卡尔曼滤波器中估计出来



专家对物理论文的渐进式作业中

估计干扰程度的几个指标的趋同效度


原文标题:

Convergent validity of several indicators measuring disruptiveness with milestone assignments to physics papers by experts

地址:

http://arxiv.org/abs/2006.10606

作者:

Lutz Bornmann,Alexander Tekles


Abstract:This study focuses on a recently introduced type of indicator measuring disruptiveness in science. Disruptive research diverges from current lines of research by opening up new lines. In the current study, we included the initially proposed indicator of this new type (Wu, Wang, & Evans, 2019) and several variants with DI1: DI5, DI1n, DI5n, and DEP. Since indicators should measure what they propose to measure, we investigated the convergent validity of the indicators. We used a list of milestone papers, selected and published by editors of Physical Review Letters, and investigated whether this human (experts - based list is related to values of the several disruption indicators variants and - if so - which variants show the highest correlation with expert judgements. We used bivariate statistics, multiple regression models, and (coarsened) exact matching (CEM) to investigate the convergent validity of the indicators. The results show that the indicators correlate differently with the milestone paper assignments by the editors. It is not the initially proposed disruption index that performed best (DI1), but the variant DI5 which has been introduced by Bornmann, Devarakonda, Tekles, and Chacko (2019). In the CEM analysis of this study, the DEP variant - introduced by Bu, Waltman, and Huang (2019) - also showed favorable results.

摘要:这项研究的重点是最近引进的一种指标,衡量干扰的科学。破坏性研究开辟了新的研究方向,从而偏离了当前的研究方向。在当前的研究中,我们包括了最初提出的这种新型指标(Wu,Wang,& Evans,2019)和 DI1: DI5,DI1n,DI5n,和 DEP 的几个变体。因为指标应该衡量他们提议衡量的东西,我们调查了指标的收敛有效性。我们使用《物理评论快报》编辑选出并发表的一份里程碑论文清单,调查这份基于专家的人类列表是否与几个干扰指标变量的值有关,如果有,哪些变量与专家判断的相关性最高。我们使用双变量统计、多元回归模型和(粗化)精确匹配(CEM)来研究指标的收敛有效性。结果表明,这些指标与编辑的里程碑论文作业的相关程度不同。最初提出的破坏性指数(DI1)并非表现最好,而是由 Bornmann、 Devarakonda、 Tekles 和 Chacko (2019)引入的变异体 DI5。在本研究的 CEM 分析中,Bu、 Waltman 和 Huang (2019)引入的 DEP 变异也显示了良好的结果



科学与算法的非中立性:

基础物理与社会之间的机器学习


原文标题:

(Non)-neutrality of science and algorithms: Machine Learning between fundamental physics and society

地址:

https://arxiv.org/abs/2006.10745

作者:

Aniello Lampo,Michele Mancarella,Angelo Piga


Abstract:The impact of Machine Learning (ML) algorithms in the age of big data and platform capitalism has not spared scientific research in academia. In this work, we will analyse the use of ML in fundamental physics and its relationship to other cases that directly affect society. We will deal with different aspects of the issue, from a bibliometric analysis of the publications, to a detailed discussion of the literature, to an overview on the productive and working context inside and outside academia. The analysis will be conducted on the basis of three key elements: the non-neutrality of science, understood as its intrinsic relationship with history and society; the non-neutrality of the algorithms, in the sense of the presence of elements that depend on the choices of the programmer, which cannot be eliminated whatever the technological progress is; the problematic nature of a paradigm shift in favour of a data-driven science (and society). The deconstruction of the presumed universality of scientific thought from the inside becomes in this perspective a necessary first step also for any social and political discussion. This is the subject of this work in the case study of ML.

摘要:机器学习(ML)算法在大数据和平台资本主义时代的影响并没有放过学术界的科学研究。在这项工作中,我们将分析机器学习在基础物理学中的应用及其与其他直接影响社会的案例的关系。我们将讨论这个问题的不同方面,从出版物的文献计量分析,到文献的详细讨论,再到学术界内外生产和工作环境的概述。分析将根据三个关键要素进行: 科学的非中立性,即科学与历史和社会的内在关系; 算法的非中立性,即依赖程序员选择的要素的存在,无论技术进步是什么都无法消除; 有利于数据驱动的科学(和社会)的范式转变的问题性质。从这个角度来看,从内部解构科学思想的普遍性成为任何社会和政治讨论的必要的第一步。这就是机器学习案例研究中这项工作的主题



通过 Twitter 

评估美国城市公园的幸福感


原文标题:

Gauging the happiness benefit of US urban parks through Twitter

地址:

http://arxiv.org/abs/2006.10658

作者:

A. J. Schwartz,P. S. Dodds,J. P. M. O'Neil-Dunne,T. H. Ricketts,C. M. Danforth


Abstract:The relationship between nature contact and mental well-being has received increasing attention in recent years. While a body of evidence has accumulated demonstrating a positive relationship between time in nature and mental well-being, there have been few studies comparing this relationship in different locations over long periods of time. In this study, we estimate a happiness benefit, the difference in expressed happiness between in- and out-of-park tweets, for the 25 largest cities in the US by population. People write happier words during park visits when compared with non-park user tweets collected around the same time. While the words people write are happier in parks on average and in most cities, we find considerable variation across cities. Tweets are happier in parks at all times of the day, week, and year, not just during the weekend or summer vacation. Across all cities, we find that the happiness benefit is highest in parks larger than 100 acres. Overall, our study suggests the happiness benefit associated with park visitation is on par with US holidays such as Thanksgiving and New Year's Day.

摘要:近年来,自然接触与心理健康的关系越来越受到人们的重视。虽然积累的大量证据表明,自然界的时间与心理健康之间存在着积极的关系,但很少有研究比较长时间内不同地点的这种关系。在这项研究中,我们对美国25个人口最多的城市的幸福感进行了估计。人们在游览公园的时候写出更快乐的话,而不是在同一时间收集的非公园用户的推文。虽然在公园和大多数城市,人们写的单词平均来说更快乐,但我们发现城市之间的差异相当大。不仅仅是在周末或者暑假,在公园的任何时候,推特在一天、一周或者一年中的任何时候都更快乐。在所有城市中,我们发现面积大于100英亩的公园幸福感最高。总的来说,我们的研究表明,公园游览带来的幸福感与美国的节日如感恩节和元旦是一样的



模拟填料和裂化


原文标题:

Simulated packing and cracking

地址:

http://arxiv.org/abs/2006.10665

作者:

Jeffrey S. Buzas,Gregory S. Warrington


Abstract:We introduce simulated packing and cracking as a technique for evaluating partisan-gerrymandering measures. We apply it to historical congressional and legislative elections to evaluate four measures: partisan bias, declination, efficiency gap, and mean-median difference. While the efficiency gap recognizes simulated packing and cracking in a completely predictable manner (a fact that follows immediately from the efficiency gap's definition) and the declination does a very good job of recording simulated packing and cracking, we conclude that both of the other two measures record it poorly. This deficiency is especially notable given the frequent use of such measures in outlier analyses.

摘要:我们介绍了模拟包装和裂解作为一种技术评估党派-重划选区的措施。我们将其应用于历史上的国会和立法选举,以评估四个指标: 党派偏见、衰退、效率差距和平均-中位数差异。虽然效率差异以一种完全可预测的方式识别模拟填充和破裂(这一事实紧接着效率差异的定义) ,而且衰减在记录模拟填充和破裂方面做了非常好的工作,我们得出结论,其他两种测量方法都记录得很差。这一缺陷特别值得注意,因为在离群值分析中经常使用这种措施



新型冠状病毒肺炎流感大流行期间

室内层面非药物干预建模: 

基于行人动力学的微观模拟方法


原文标题:

Modeling indoor-level non-pharmaceutical interventions during the COVID-19 pandemic: a pedestrian dynamics-based microscopic simulation approach

地址:

http://arxiv.org/abs/2006.10666

作者:

Yao Xiao,Mofeng Yang,Zheng Zhu,Hai Yang,Lei Zhang,Sepehr Ghader


Abstract:Mathematical modeling of epidemic spreading has been widely adopted to estimate the threats of epidemic diseases (i.e., the COVID-19 pandemic) as well as to evaluate epidemic control interventions. The indoor place is considered to be a significant epidemic spreading risk origin, but existing widely-used epidemic spreading models are usually limited for indoor places since the dynamic physical distance changes between people are ignored, and the empirical features of the essential and non-essential travel are not differentiated. In this paper, we introduce a pedestrian-based epidemic spreading model that is capable of modeling indoor transmission risks of diseases during people's social activities. Taking advantage of the before-and-after mobility data from the University of Maryland COVID-19 Impact Analysis Platform, it's found that people tend to spend more time in grocery stores once their travel frequencies are restricted to a low level. In other words, an increase in dwell time could balance the decrease in travel frequencies and satisfy people's demand. Based on the pedestrian-based model and the empirical evidence, combined non-pharmaceutical interventions from different operational levels are evaluated. Numerical simulations show that restrictions on people's travel frequency and open-hours of indoor places may not be universally effective in reducing average infection risks for each pedestrian who visit the place. Entry limitations can be a widely effective alternative, whereas the decision-maker needs to balance the decrease in risky contacts and the increase in queue length outside the place that may impede people from fulfilling their travel needs.

摘要:流行病传播的数学模型已经被广泛地应用于估计流行病的威胁(即新型冠状病毒肺炎流行病)以及评估流行病控制干预措施。室内场所被认为是一个重要的传染病传播风险源,但现有的广泛应用的传染病传播模型往往局限于室内场所,忽略了人与人之间物理距离的动态变化,没有区分基本出行和非基本出行的经验特征。本文介绍了一种基于行人的传染病传播模型,该模型能够模拟人们在社会活动中的室内传播疾病的风险。利用马里兰大学学院市分校新型冠状病毒肺炎影响分析平台的前后移动性数据,研究发现,一旦出行频率被限制在一个较低的水平,人们倾向于花更多的时间在杂货店。换句话说,停留时间的增加可以平衡旅行频率的减少和满足人们的需求。基于行人为基础的模型和经验证明,来自不同操作层面的综合非药物干预进行了评估。数字模拟结果显示,限制人们的出行频率和室内地方的开放时间,可能不会普遍有效地降低每位前往该地方的行人的平均感染风险。进入限制可能是一个广泛有效的替代办法,而决策者需要在风险联系减少和可能妨碍人们满足其旅行需求的场所外排队长度增加之间取得平衡



未来美国电网的异功能图弹性


原文标题:

Hetero-functional Graph Resilience of the Future American Electric Grid

地址:

http://arxiv.org/abs/2006.10678

作者:

Dakota J. Thompson,Wester C. H. Schoonenberg,Amro M. Farid


Abstract:As climate change takes hold in the 21st century, it places an impetus to decarbonize the American electric power system with renewable energy resources. This paper presents a structural resilience analysis of the American electric power system that incrementally incorporates architectural changes including meshed distribution lines, distributed generation, and energy storage solutions. A hetero-functional graph analysis confirms our formal graph understandings from network science in terms of cumulative degree distributions and traditional attack vulnerability measures. Additionally, The paper shows that hetero-functional graphs more precisely describe the changes in functionality associated with the addition of distributed generation and energy storage. Finally, it demonstrates that the addition of all three types of mitigation measures enhance the grid's structural resilience; even in the presence of disruptive attacks. The paper concludes that there is no structural trade-off between grid sustainability and resilience.

摘要:随着21世纪气候变化的深入,可再生能源的使用推动了美国电力系统的脱碳。本文介绍了美国电力系统的结构弹性分析,逐步纳入建筑变化,包括网状配电线路,分散式发电和能源储存解决方案。异功能图分析从累积度分布和传统攻击脆弱性度量的角度证实了我们从网络科学中得到的正式图理解。此外,本文还表明,异质函数图更精确地描述了与分散式发电和能量储存相关的功能变化。最后,它表明,所有三种类型的缓解措施的增加加强了电网的结构弹性,即使在存在破坏性攻击。本文的结论是,电网的可持续性和复原力之间不存在结构性的权衡



21新型冠状病毒肺炎非洲的冲突:

社会距离、粮食脆弱性和福利反应


原文标题:

Conflict in Africa during COVID-19: social distancing, food vulnerability and welfare response

地址:

http://arxiv.org/abs/2006.10696

作者:

Roxana Gutiérrez-Romero


Abstract:We study the effect of social distancing, food vulnerability, welfare and labour COVID-19 policy responses on riots, violence against civilians and food-related conflicts. Our analysis uses georeferenced data for 24 African countries with monthly local prices and real-time conflict data reported in the Armed Conflict Location and Event Data Project (ACLED) from January 2015 until early May 2020. Lockdowns and recent welfare policies have been implemented in light of COVID-19, but in some contexts also likely in response to ongoing conflicts. To mitigate the potential risk of endogeneity, we use instrumental variables. We exploit the exogeneity of global commodity prices, and three variables that increase the risk of COVID-19 and efficiency in response such as countries colonial heritage, male mortality rate attributed to air pollution and prevalence of diabetes in adults. We find that the probability of experiencing riots, violence against civilians, food-related conflicts and food looting has increased since lockdowns. Food vulnerability has been a contributing factor. A 10% increase in the local price index is associated with an increase of 0.7 percentage points in violence against civilians. Nonetheless, for every additional anti-poverty measure implemented in response to COVID-19 the probability of experiencing violence against civilians, riots and food-related conflicts declines by approximately 0.2 percentage points. These anti-poverty measures also reduce the number of fatalities associated with these conflicts. Overall, our findings reveal that food vulnerability has increased conflict risks, but also offer an optimistic view of the importance of the state in providing an extensive welfare safety net.

摘要:我们研究了社会距离、粮食脆弱性、福利和劳动力 / 新型冠状病毒肺炎政策对骚乱、针对平民的暴力和与粮食有关的冲突的影响。我们的分析使用了24个非洲国家的地理参考数据,其中包括2015年1月至2020年5月初武装冲突地点和事件数据项目中报告的每月当地价格和实时冲突数据。封锁政策和最近的福利政策已经根据新型冠状病毒肺炎实施,但在某些情况下也可能是为了应对正在发生的冲突。为了降低内源性的潜在风险,我们使用工具变量。我们利用了全球商品价格的外生性,以及增加新型冠状病毒肺炎风险和效率的3个变量,如国家殖民遗产、空气污染导致的男性死亡率和成年人糖尿病流行率。我们发现,自封锁以来,发生骚乱、针对平民的暴力、与粮食有关的冲突和抢劫粮食的可能性有所增加。食品的脆弱性一直是一个影响因素。当地价格指数上升10% ,对平民的暴力行为就会增加0.7个百分点。尽管如此,为了应对新型冠状病毒肺炎,每增加一项反贫困措施,发生针对平民的暴力事件、骚乱和与粮食有关的冲突的概率就会下降大约0.2个百分点。这些扶贫措施还减少了与这些冲突有关的死亡人数。总的来说,我们的研究结果表明,食品的脆弱性增加了冲突的风险,但也为国家提供广泛的福利安全网的重要性提供了乐观的看法



振动和噪声作用下

捕光复合体的多尺度循环动力学


原文标题:

Multiscale cyclic dynamics in light harvesting complex in presence of vibrations and noise

地址:

http://arxiv.org/abs/1804.06260

作者:

Shmuel Gurvitz,Gennady P. Berman,Richard T. Sayre


Abstract:Starting from the many-body Schr"odinger equation, we derive a new type of Lindblad Master equations describing a cyclic exciton/electron dynamics in the light harvesting complex and the reaction center. These equations resemble the Master equations for the electric current in mesoscopic systems, and they go beyond the single-exciton description by accounting for the multi-exciton states accumulated in the antenna, as well as the charge-separation, fluorescence and photo-absorption. Although these effects take place on very different timescales, their inclusion is necessary for a consistent description of the exciton dynamics. Our approach reproduces both coherent and incoherent dynamics of exciton motion along the antenna in the presence of vibrational modes and noise. We applied our results to evaluate energy (exciton) and fluorescent currents as a function of sunlight intensity.

摘要:从多体薛定谔方程出发,导出了一类新的描述捕光络合物和反应中心的循环激子 / 电子动力学的 Lindblad 主方程。这些方程类似于介观系统中电流的主方程,它们考虑了天线中积累的多激子态,以及电荷分离、荧光和光吸收,超越了单激子描述。虽然这些效应发生在非常不同的时间尺度上,但它们的包含对于一致地描述激子动力学是必要的。我们的方法在存在振动模式和噪声的情况下,沿着天线产生相干和非相干的激子运动动力学。我们应用我们的结果来评估能量(激子)和荧光电流作为阳光强度的函数



通过微血管分叉实现

细胞血液纳米粒子的异质分配


原文标题:

Heterogeneous partition of cellular blood-borne nanoparticles through microvascular bifurcations

地址:

http://arxiv.org/abs/2006.10117

作者:

Zixiang L. Liu,Jonathan R. Clausen,Justin L. Wagner,Kimberly S. Butler,Dan S. Bolintineanu,Jeremy B. Lechman,Rekha R. Rao,Cyrus K. Aidun


Abstract:Blood flowing through microvascular bifurcations has been an active research topic for many decades, while the partitioning pattern of nanoscale solutes in the blood remains relatively unexplored. Here, we demonstrate a multiscale computational framework for direct numerical simulation of the nanoparticle (NP) partitioning through physiologically-relevant vascular bifurcations in the presence of red blood cells (RBCs). The computational framework is established by embedding a newly-developed particulate suspension inflow/outflow boundary condition into a multiscale blood flow solver. The computational framework is verified by recovering a tubular blood flow without a bifurcation and validated against the experimental measurement of an intravital bifurcation flow. The classic Zweifach-Fung (ZF) effect is shown to be well captured by the method. Moreover, we observe that NPs exhibit a ZF-like heterogeneous partition in response to the heterogeneous partition of the RBC phase. The NP partitioning prioritizes the high-flow-rate daughter branch except for extreme (large or small) suspension flow partition ratios under which the complete phase separation tends to occur. By analyzing the flow field and the particle trajectories, we show that the ZF-like heterogeneity in NP partition can be explained by the RBC-entrainment effect caused by the deviation of the flow separatrix preceded by the tank-treading of RBCs near the bifurcation junction. The recovery of homogeneity in the NP partition under extreme flow partition ratios is due to the plasma skimming of NPs in the cell-free layer. These findings, based on the multiscale computational framework, provide biophysical insights to the heterogeneous distribution of NPs in microvascular beds that are observed pathophysiologically.

摘要:血液在微血管分叉中的流动一直是近几十年来研究的热点,而纳米溶质在血液中的分配模式则相对较少。在这里,我们展示了一个多尺度的计算框架,直接数值模拟的纳米粒子(NP)划分通过生理相关的血管分岔的存在红细胞(RBCs)。通过在多尺度血流求解器中嵌入一个新发展的悬浮颗粒流入 / 流出边界条件,建立了计算框架。计算框架通过一个没有分叉的管状血流的恢复得到了验证,并通过一个活体内分叉血流的实验测量得到了验证。该方法很好地捕捉了经典的 Zweifach-Fung (ZF)效应。此外,我们观察到,NPs 表现出一个 zf 类异质分配响应的红细胞阶段的异质分配。Np 分区将高流速子分支按优先顺序排列,除了极端(大或小)的悬浮流分区比例,在这种情况下往往会发生完全的相分离。通过对流场和颗粒运动轨迹的分析,我们发现类 zf 非均匀性可以用 rbc- 夹带效应来解释。极端流动分配比下 NP 分配均匀性的恢复是由于无胞层中 NPs 的等离子体掠过所致。这些发现,基于多尺度的计算框架,提供了生物物理学的见解,在病理生理学观察微血管床 NPs 的不均匀分布



组织病理学和高幅超声中

单泡动力学的建模与验证


原文标题:

Single-bubble dynamics in histotripsy and high-amplitude ultrasound: Modeling and validation

地址:

http://arxiv.org/abs/2006.10171

作者:

Lauren Mancia,Mauro Rodriguez,Jonathan Sukovich,Zhen Xu,Eric Johnsen


Abstract:A variety of approaches have been used to model the dynamics of a single, isolated bubble nucleated by a microsecond length high-amplitude ultrasound pulse (e.g., a histotripsy pulse). Until recently, the lack of single--bubble experimental radius vs. time data for bubble dynamics under a well-characterized driving pressure has limited model validation efforts. This study uses radius vs. time measurements of single, spherical histotripsy-nucleated bubbles in water [Wilson et al., Phys. Rev. E, 2019, 99, 043103] to quantitatively compare and validate a variety of bubble dynamics modeling approaches, including compressible and incompressible models as well as different thermal models. A strategy for inferring an analytic representation of histotripsy waveforms directly from experimental radius vs. time and cavitation threshold data is presented. We compare distributions of a calculated validation metric obtained for each model applied to 8experimental data sets. There is minimal distinction () among the modeling approaches for compressibility and thermal effects considered in this study. These results suggest that our proposed strategy to infer the waveform, combined with simple models minimizing parametric uncertainty and computational resource demands accurately represent single-bubble dynamics in histotripsy, including at and near the maximum bubble radius. Remaining sources of parametric and model-based uncertainty are discussed.

摘要:人们已经使用了多种方法来模拟单个孤立气泡的动力学,这些气泡由微秒长度的高振幅超声脉冲(例如组织病理脉冲)形核。直到最近,缺乏单个气泡实验半径与时间数据的气泡动力学的驱动压力下,良好的特点限制了模型验证的努力。这项研究使用半径与时间的测量单个,球形组织病理核心气泡在水中[威尔逊等人。2019,99,043103]定量比较和验证各种气泡动力学模型的方法,包括可压缩和不可压缩模型以及不同的热模型。提出了一种直接从实验半径随时间变化和空化阈值数据推导直组织病理波形解析表达式的方法。我们比较分布的计算验证度量获得的每个模型适用于



包括根茎生长在内的

植被模式的一般模型


原文标题:

A general model for vegetation patterns including rhizome growth

地址:

http://arxiv.org/abs/1908.04603

作者:

Daniel Ruiz-Reynés,Francesca Schönsberg,Emilio Hernández-García,Damià Gomila


Abstract:Vegetation patterns, a natural phenomenon observed worldwide, are typically driven by spatially distributed feedback. However, the spatial colonization mechanisms of clonal plants, driven by the growth of a rhizome, are usually not considered in prototypical models. Here we propose a general equation for the vegetation density that includes all main clonal-growth features as well as the essential ingredients leading to spatial self-organization. This generic model reproduces the phase diagram of a fully detailed model of clonal growth. The relation of each term of the model with the mechanisms of clonal growth is discussed.

摘要:植被模式是在世界范围内观察到的一种自然现象,通常是由空间分布的反馈驱动的。然而,克隆植物在根状茎生长驱动下的空间定殖机制在原型模型中通常不被考虑。在这里,我们提出了一个包括所有主要克隆生长特征以及导致空间自我组织的基本要素的植被密度的一般方程。这个通用模型再现了一个完全详细的克隆生长模型的相图。讨论了模型各项与克隆生长机制的关系



运动蛋白质

通过微管交叉转运的随机模拟


原文标题:

Stochastic modelling of collective motor protein transport through a crossing of microtubules

地址:

http://arxiv.org/abs/2006.10416

作者:

Adélaïde Raguin,Norbert Kern,Andrea Parmeggiani


Abstract:The cytoskeleton in eukaryotic cells plays several crucial roles. In terms of intracellular transport, motor proteins use the cytoskeletal filaments as a backbone along which they can actively transport biological cargos such as vesicles carrying biochemical reactants. Crossings between such filaments constitute a key element, as they may serve to alter the destination of such payload. Although motor proteins are known to display a rich behaviour at such crossings, the latter have so far only been modelled as simple branching points. Here we explore a model for a crossing between two microtubules which retains the individual tracks consisting of protofilaments, and we construct a schematic representation of the transport paths. We study collective transport exemplified by the Totally Asymmetric Simple Exclusion Process (TASEP), and provide a full analysis of the transport features and the associated phase diagram, by a generic mean-field approach which we confirm through particle-based stochastic simulations. In particular we show that transport through such a compound crossing cannot be approximated from a coarse-grained structure with a simple branching point. Instead, it gives rise to entirely new and counterintuitive features: the fundamental current-density relation for traffic flow is no longer a single-valued function, and it furthermore differs according to whether it is observed upstream or downstream from the crossing. We argue that these novel features may be directly relevant for interpreting experimental measurements.

摘要:真核细胞中的细胞骨架起着几个重要的作用。在细胞内转运方面,运动蛋白利用细胞骨架丝作为骨干,沿着它们可以积极地运输生物物质,如载有生化反应物的小泡。细丝之间的交叉是一个关键要素,因为它们可能有助于改变这种有效载荷的目的地。虽然我们知道运动蛋白在这种交叉过程中表现出丰富的行为,但迄今为止,运动蛋白仅仅被模拟为简单的分支点。在这里,我们探索一个模型之间的交叉两个微管保留个人轨道组成的原丝,我们构建一个图示表示的传输路径。本文以完全非对称简单排斥过程(TASEP)为例研究了集体输运,并用一般的平均场方法对输运特征和相图进行了全面的分析,并通过基于粒子的随机模拟进行了验证。我们特别指出,通过这种混合杂交的传输不能近似于粗粒度结构和简单的分支点。相反,它产生了全新的违反直觉的特征: 交通流的基本电流密度关系不再是一个单值函数,而是根据在交叉口上游或下游观察到的电流密度关系而有所不同。我们认为这些新奇的特征可能与解释实验测量直接相关



减少SARS-COV-2和其他病毒

对 spike 蛋白渗透的有效途径: 

通过表面粒子静电荷协商


原文标题:

An effective approach to reduce the penetration potential of Sars-Cov-2 and other viruses by spike protein: Through surface particle electrostatic charge negotiation

地址:

http://arxiv.org/abs/2006.10603

作者:

Kausik Rakshit,Sudip Chatterjee,Durjoy Bandyopadhyay,Somsekhar Sarkar


Abstract:The objective of this paper is to provide a mathematical model to construct a barrier that may be useful to prevent the penetration of different viruses (Eg. SARS-COV-2) as well as charged aerosols through the concept of electrostatic charge negotiation. (Fusion for the opposite types of charges and repulsion for the similar types of charges). Reviewing the works of different authors, regarding charges, surface charge densities ({sigma}), charge mobility ({mu}) and electrostatic potentials of different aerosols under varied experimental conditions, a similar intensive study has also been carried out to investigate the electron donating and accepting (hole donating) properties of the spike proteins (S-proteins) of different RNA and DNA viruses, including SARS-COV-2. Based upon the above transport properties of electrons of different particles having different dimensions, a mathematical model has been established to find out the penetration potential of those particles under different electrostatic fields. An intensive study have been carried out to find out the generation of electrostatic charges due to the surface emission of electrons (SEE), when a conducting material like silk, nylon or wool makes a friction with the Gr IV elements like Germanium or Silicon, it creates an opposite layer of charges in the outer conducting surface and the inner semiconducting surface separated by a dielectric materials. This opposite charge barriers may be considered as Inversion layers (IL). The electrostatic charges accumulated in the layers between the Gr IV Ge is sufficient enough to either fuse or repel the charges of the spike proteins of the RNA, DNA viruses including SARS-Cov-2 (RNA virus) or the aerosols.

摘要:本文的目的是提供一个数学模型来构建一个屏障,这个屏障可能有助于防止不同病毒的渗透。Sars-cov-2)以及通过静电电荷协商概念带电气溶胶。(聚变为相反类型的电荷和斥力为类似类型的电荷)。本文回顾了不同作者在不同实验条件下对不同气溶胶的电荷、表面电荷密度、电荷迁移率和静电势的研究工作,并对不同 RNA 和 DNA 病毒(包括 SARS-COV-2病毒)的 s 蛋白(s 蛋白)的电子供给和接受(空穴供给)特性进行了类似的深入研究。根据不同尺寸粒子的电子输运特性,建立了粒子在不同静电场作用下的穿透势的数学模型。本文对丝、尼龙、羊毛等导电材料与锗、硅等 Gr IV 元素摩擦时,在外导电表面和内半导电表面分别产生相反的电荷层进行了深入的研究。这种相反的电荷势垒可以看作是反转层。Gr IV Ge 蛋白层间积累的静电荷足以融合或击退 RNA、包括 SARS-Cov-2(RNA 病毒)在内的 DNA 病毒或气溶胶蛋白的电荷



喷气火车在通话中

产生远程湍流喷气式传输,

可能与无症状病毒传播有关


原文标题:

Puff trains in speaking produce long-range turbulent jet-like transport potentially relevant to asymptomatic spreading of viruses

地址:

http://arxiv.org/abs/2006.10671

作者:

Manouk Abkarian,Simon Mendez,Nan Xue,Fan Yang,Howard A. Stone


Abstract:Droplet generation and transport during coughing and sneezing has been studied for decades to characterize disease transmission by symptomatic individuals. Nevertheless, many reports document that asymptomatic and presymptomatic individuals contribute to the spread of COVID-19, probably during conversations in social interactions. Researchers have shown that droplet emission occurs during speech, yet there are few quantitative studies of the flows that provide the transport mechanism; the relevant fluid dynamics is largely unstudied. This lack of quantitative characterization means that when virus is present there is little public health guidance for understanding risk and mitigation strategies, e.g. the "six-foot rule". Here we analyze flows during breathing and speaking, including linguistic features, using order-of-magnitudes estimates, numerical simulations, and laboratory experiments. We show how plosive sounds like `P' are associated with vortical structures, leading to rapid transport over half a meter in a split second. When produced individually, puffs decay over a meter, with the distance traveled in time scaling as Lt1/4, and mix with the slower environmental circulation. In contrast, the transport of exhaled material over time scales longer than a few seconds, characteristic of speech, which is effectively a train of puffs, is a conical turbulent jet with a scaling law Lt1/2. Typically, the exhaled air in front of a speaker extends 2 m after 30 seconds of normal speech. We believe this work will inform thinking about aerosol transport in disease transmission for humans and other animals, and yield a better understanding of linguistic aerodynamics, i.e., aerolinguistics.

摘要:数十年来,人们一直在研究咳嗽和打喷嚏过程中液滴的产生和运输,以表征有症状个体的疾病传播特征。然而,许多报告表明,无症状和有症状的个体可能在社交互动中的谈话中促进了COVID-19的传播。研究人员已经表明,液滴的散发是在语音过程中发生的,但很少有定量研究提供这种流动机制的流动。相关的流体动力学很大程度上未被研究。这种缺乏定量特征的手段意味着,当存在病毒时,几乎没有公共卫生指导来了解风险和缓解策略,例如“六尺法则”。在这里,我们分析呼吸和说话期间的流量,包括语言特征,使用量级估计,数值模拟和实验室实验。我们展示了像“ P”这样的爆破音是如何与旋涡结构相关联的,从而导致在一秒钟内快速传输超过半米。当单独生产时,粉扑会随着距离的推移而逐渐衰减一米t,Ť缩放为 大号Ť1个/4,并与较慢的环境流通混合在一起。相比之下,呼出的物质在时间尺度上的传输时间长于几秒钟,而语音特征(实际上是一连串的抽吸)是具有比例定律的圆锥形湍流射流大号Ť1个/2。通常,说话者前面的呼出空气在正常语音播放30秒后会延伸2 m。我们相信这项工作将为人们在传播人类和其他动物的疾病中进行气溶胶运输提供参考,并更好地理解语言空气动力学,即航空语言学。


来源:集智斑图
编辑:王建萍




新型冠状病毒肺炎在不同社区传播的 SIR 模型假设 | 网络科学论文速递30篇-集智俱乐部


集智俱乐部QQ群|877391004

商务合作及投稿转载|swarma@swarma.org

◆ ◆ 

搜索公众号:集智俱乐部


加入“没有围墙的研究所”

新型冠状病毒肺炎在不同社区传播的 SIR 模型假设 | 网络科学论文速递30篇-集智俱乐部

让苹果砸得更猛烈些吧!