Recent studies of the history of mathematics have shed light on the diversity of mathematical practices in the ancient world. In this article, I address this issue from two perspectives. First, I ...analyze different mathematical instruments used in different domains in 12th and 13th century China. Second, by analyzing how the text is related to the problems written down in the same period, I argue that there existed two categories of mathematical problems. As a result, I suggest that problems, textual procedures, and material operations should be considered together when regarding various mathematical practices in mathematical and non-mathematical fields.
最近的數學史研究已經清楚地揭示出古代世界數學實作的多樣性。在本文中, 我從兩方面探討這一問題。首先, 我分析12至13世紀中國的四個不同領域所使用的數學工具。其次, 透過分析12至13世紀中國關於數學問題的文本是怎樣寫下來的, 我論證存在兩種不同類型的數學問題。因此, 我認為當研究數學和非數學領域內多樣的數學實作的時候, 問題文本、算法文本和物質操作必須放在一起考慮。
On Qin Jiushao's writing system Yiwen, Zhu
Archive for history of exact sciences,
07/2020, Letnik:
74, Številka:
4
Journal Article
Recenzirano
The Mathematical Book in Nine Chapters, written by Qin Jiushao in 1247, is a masterpiece that is representative of Chinese mathematics at that time. Most of the previous studies have focused on its ...mathematical achievements, while few works have addressed the counting diagrams that Qin used as a writing system. Based on a seventeenth-century copy of Qin's treatise (i.e., Zhao Qimei's 1616 handwritten copy), this paper systematically analyzes the writing system, which includes both a numeral system and a linear system. It argues that Qin provided a new representation of mathematics in addition to textual procedures, detailed solutions, and operations carried out with counting rods. Moreover, this new representation was used to connect mathematical practices within and outside the text and should be understood in its textual context. Therefore, Qin's writing system represents an intermediate phase in the textualization and symbolization of Chinese mathematics in thirteenth-century China.
The etiology of major depressive disorder (MDD), the leading cause of worldwide disability, is unknown. The neurogenic hypothesis proposes that MDD is linked to impairments of adult neurogenesis in ...the hippocampal dentate gyrus (DG), while the effects of antidepressants are mediated by increased neurogenesis. However, alterations in neurogenesis and endophenotypes are not always causally linked, and the relationship between increased neurogenesis and altered behavior is controversial. To address causality, we used chemogenetics in transgenic mice to selectively manipulate activity of newborn DG neurons. Suppressing excitability of newborn neurons without altering neurogenesis abolish the antidepressant effects of fluoxetine. Remarkably, activating these neurons is sufficient to alleviate depression-like behavior and reverse the adverse effects of unpredictable chronic mild stress. Our results demonstrate a direct causal relationship between newborn neuronal activity and affective behavior. Thus, strategies that target not only neurogenesis but also activity of newborn neurons may lead to more effective antidepressants.
Single-cell transcriptome profiling of heterogeneous tissues can provide high-resolution windows into developmental dynamics and environmental responses, but its application to plants has been ...limited. Here, we used the high-throughput Drop-seq approach to profile >12,000 cells from Arabidopsis roots. This identified numerous distinct cell types, covering all major root tissues and developmental stages, and illuminated specific marker genes for these populations. In addition, we demonstrate the utility of this approach to study the impact of environmental conditions on developmental processes. Analysis of roots grown with or without sucrose supplementation uncovers changes in the relative frequencies of cell types in response to sucrose. Finally, we characterize the transcriptome changes that occur across endodermis development and identify nearly 800 genes with dynamic expression as this tissue differentiates. Collectively, we demonstrate that single-cell RNA-seq can be used to profile developmental processes in plants and show how they can be altered by external stimuli.
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•RNA expression profiling of >12,000 single Arabidopsis root cells by Drop-seq•Recovered major tissue types and cell stages and identified specific marker genes•Sucrose alters cell type proportions but does not profoundly change cell identities•Identified ∼800 genes dynamically expressed across endodermis development
The application of single-cell transcriptome profiling to plants has been limited. Shulse et al. performed Drop-seq on Arabidopsis roots, generating a transcriptional resource for >12,000 cells across major populations. This revealed marker genes for distinct cell types, cell frequency changes resulting from sucrose addition, and genes dynamically regulated during development.
Sequence polymorphisms in a 58-kilobase (kb) interval on chromosome 9p21 confer a markedly increased risk of coronary artery disease (CAD), the leading cause of death worldwide. The variants have a ...substantial effect on the epidemiology of CAD and other life-threatening vascular conditions because nearly one-quarter of Caucasians are homozygous for risk alleles. However, the risk interval is devoid of protein-coding genes and the mechanism linking the region to CAD risk has remained enigmatic. Here we show that deletion of the orthologous 70-kb non-coding interval on mouse chromosome 4 affects cardiac expression of neighbouring genes, as well as proliferation properties of vascular cells. Chr4 70kb/ 70kb mice are viable, but show increased mortality both during development and as adults. Cardiac expression of two genes near the non-coding interval, Cdkn2a and Cdkn2b, is severely reduced in chr4 70kb/ 70kb mice, indicating that distant-acting gene regulatory functions are located in the non-coding CAD risk interval. Allele-specific expression of Cdkn2b transcripts in heterozygous mice showed that the deletion affects expression through a cis-acting mechanism. Primary cultures of chr4 70kb/ 70kb aortic smooth muscle cells exhibited excessive proliferation and diminished senescence, a cellular phenotype consistent with accelerated CAD pathogenesis. Taken together, our results provide direct evidence that the CAD risk interval has a pivotal role in regulation of cardiac Cdkn2a/b expression, and suggest that this region affects CAD progression by altering the dynamics of vascular cell proliferation.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Reinforcement learning is a new research hotspot in the energy management strategy. At present, some problems in the application of reinforcement learning to energy management control still exist, ...including sparse reward, convergence speed, generalization ability, etc. This paper proposes a self-supervised reinforcement learning method based on a Deep Q-learning approach for fuel-saving optimization of a plug-in hybrid electric vehicle (PHEV). First, a detailed vehicle powertrain model of the Prius is built. Second, we use the self-supervised learning model to enrich the reward function. The reward function consists of two parts: internal and external rewards. Finally, to prevent the self-supervised model from falling into the “self-good” situation, a reinforcement learning calibration method is proposed. The vehicle exploration method is more effective because of the enrichment of the reward function. Furthermore, following the characteristics of self-supervised learning, we have also constructed a new driving cycle to verify the generalization ability. Results show that our proposed deep reinforcement learning method based on self-supervised and learning calibration realizes faster training convergence and lower fuel consumption than the traditional policy, and its fuel economy can reach approximately the global optimum under our new driving cycle.
•The method used in this can enhance the vehicle's ability to explore the environment.•Internal rewards were constructed using self-supervised learning methods.•The algorithm has generalization ability in energy management control strategy.•The reward function is corrected with the reinforcement learning calibration.
•A data-driven approach to the Passenger-to-Train Assignment problem, with a detailed reconstruction of passenger’s movements.•Aggregate performance metrics, such as estimated train loads, left ...behind probabilities to assess capacity utilization.•A computationally efficient method to estimate time dependent crowding levels at stations and platforms.•A method to estimate the walk speed and egress time distributions at a given station from AFC and AVL data.
The paper presents a methodology for assigning passengers to individual trains using: (i) fare transaction records from Automatic Fare Collection (AFC) systems and (ii) Automatic Vehicle Location (AVL) data from train tracking systems. The proposed Passenger-to-Train Assignment Model (PTAM) is probabilistic and links each fare transaction to a set of feasible train itineraries. The method estimates the probability of the passenger boarding each feasible train, and the probability distribution of the number of trains a passenger is unable to board due to capacity constraints. The access/egress time distributions are important inputs to the model. The paper also suggests a maximum likelihood approach to estimate these distributions from AFC and AVL data. The methodology is applied in a case study with data from a major, congested, subway system during peak hours. Based on actual AFC and train tracking data, synthetic data was generated to validate the model. The results, both in terms of the trains passengers are assigned to and train loads, are similar to the “true” observations from the synthetic data. The probability of a passenger being left behind (due to capacity constraints) in the actual system is also estimated by time of day and compared with survey data collected by the agency at the same station. The left behind probabilities can be accurately estimated from the assignment results. Furthermore, it is shown that the PTAM output can also be used to estimate crowding metrics at transfer stations.
The aim of this paper is to bring to light a previously unknown geometrical method for extracting the square root in seventh century China. In order to achieve this goal, a seventh century commentary ...by the scholar Jia Gongyan, 賈公彥, on a Confucian canon, the Rites of Zhou Dynasty Zhouli 周禮, is analysed. This is compared with the commentary by his contemporary Li Chunfeng, 李淳風, which is referred to in another mathematical book, the Mathematical Procedures of the Five Canons, Wujing Suanshu 五經筭術. Although these two scholars probably knew each other, they used very different methods to solve the same problem in relation to square root extraction. It is argued that the differences mainly lie in two aspects: firstly, Jia Gongyan mostly made use of geometry while Li Chunfeng used counting rods; secondly, the two methods had different geometrical interpretations. Given the fact that the method of square root extraction Jia Gongyan uses is one among many other methods he employed in mathematics, and it has the same features as the others; moreover, other commentators on the Confucian Canons use similar mathematical methods, this paper closes with a general discussion on mathematical cultures. It is suggested that there were three elements to mathematical practice in seventh century China: geometry, counting rods, and written texts. The interplay and structure between the three elements is seen to influence mathematical practices.
本文通過分析唐代學者賈公彥對《周禮 •考工記》 “參分弓長” 和 “軓前十尺” 的注疏 , 揭示出一種先前未被學術界關 注到的幾何開方術。繼而 , 將之與李淳風對《五經筭術》中 “參分弓長” 問題的註解相比較 , 我們可以看到 : 儘管賈公彥與 李淳風很可能互相認識 , 但是他們用了截然不同的開方辦法去處理同樣的問題。本文論證兩者的差別主要在兩方面 : 一 , 賈公彥的算法是利用幾何 , 而李淳風的算法是利用筭籌 ; 二 , 兩種算法具有不同的幾何解釋。基於如下事實 : 賈公彥開方 術的特色在他其他的注疏中也有體現 , 而且唐代其他學者對於儒家經典的注疏中也有類似算法 , 本文就唐代數學文化做 一般性的討論 , 認為 : 唐代的數學實作主要包括三大要素 : 幾何 , 筭籌和文本 , 三者之間的互動及其形成的結構對唐代數 學文化產生了重要影響。
Although live streaming commerce (LSC) has become a daily phenomenon in the digital economy, its spatial impact is still not yet fully understood. LSC is typical online-offline producer-customer ...intermediation type of the platform urbanism. Based on unique data from Huitun on the LSC activities in Taobao (Alibaba), we trace how digital streamers/platform with their own geographies connect suppliers with customers from different regions. Most digital streamers are located in urban areas, so they form a kind of urban intermediation among different regions. We argue that digital streamers, product suppliers, and customers form new urban systems because of their relational work and intermediation. We also show how intermediary cities emerge and change their positions in the new urban system. We demonstrate that retail is no longer based on the traditional service radius within a city but on a function of the intermediation of customers and suppliers from different regions. Finally, we provide evidence indicating that market access, transport infrastructure, and market consumption capacity are important factors that help explain such positions.
•Digital platform is reshaping the commercial pattern; LSC is an online-offline producer-consumer intermediation.•Hybrid actors in LSC influence structure of urban systems due to their relationship and intermediation.•Intermediary cities emerge in LSC urban system and help the peripheral cities to realize position upgrade and development.•Retail is no longer based on the traditional service radius but on a function of inter-regional intermediation.
Non-coding “ultraconserved” regions containing hundreds of consecutive bases of perfect sequence conservation across mammalian genomes can function as distant-acting enhancers. However, initial ...deletion studies in mice revealed that loss of such extraordinarily constrained sequences had no immediate impact on viability. Here, we show that ultraconserved enhancers are required for normal development. Focusing on some of the longest ultraconserved sites genome wide, located near the essential neuronal transcription factor Arx, we used genome editing to create an expanded series of knockout mice lacking individual or combinations of ultraconserved enhancers. Mice with single or pairwise deletions of ultraconserved enhancers were viable and fertile but in nearly all cases showed neurological or growth abnormalities, including substantial alterations of neuron populations and structural brain defects. Our results demonstrate the functional importance of ultraconserved enhancers and indicate that remarkably strong sequence conservation likely results from fitness deficits that appear subtle in a laboratory setting.
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•The Arx locus has a high density of very long ultraconserved forebrain enhancers•Single or pairwise deletion of these enhancers results in viable mice in all cases•In most cases, individual enhancer loss results in developmental anomalies•Selection against these fitness deficits likely contributes to ultraconservation
Although initial studies suggested that loss of ultraconserved enhancers had no impact on viability, these sequences are now shown to be required for normal development.
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