3,330 research outputs found
Spatiotemporal dynamics of carbon cycling and thermokarst in response to climate and fire-regime changes in the Arctic tundra biome
No full textAmplified climate change and fire regime shifts in the northern high latitudes are posing growing threat to key properties and functions of tundra ecosystems, including soil carbon stock, permafrost stability and vegetation types. However, it remains poorly understood how tundra ecosystems will feedback to the combined forces of changing climate and fire disturbance. In this study, I integrated paleoecology, numerical modeling and remote sensing observation to address (1) the resilience and sensitivity of tundra carbon stocks to shifting fire regimes, (2) the consequences of climate change and fire disturbance on thermokarst disturbance (e.g. collapse of ground surface after permafrost thaw), and (3) the patterns of shrub expansion in heterogenous tundra landscape in response to accelerated warming and fire disturbance. My results indicate that fire disturbance has threshold effects on tundra carbon stocks. Variation in fire return intervals from 5000 to 900 years causes minimal carbon stock loss (<5%). However, increasing fire frequency beyond every 800 years is projected to trigger sustained mobilization of ancient soil organic matter that leads to irreversible carbon stock loss from permafrost. Multi-decade remote sensing observations revealed that tundra fires resulted in pervasive thermokarst formation, and that this impact lasted more than four decades. Nevertheless, substantial spatial heterogeneity exists regarding thermokarst formation and the greatest amount of thermokarst appears in severely burned tundra ecosystems in ice-rich areas. Although fire disturbance is a strong force exacerbating permafrost degradation, widespread warming surpasses sporadic burning as the primary driver responsible for ~90% of thermokarst growth in northern Alaskan tundra over the past ~70 yrs. Permafrost thawing strongly influences shrub cover dynamics in tundra ecosystems, but the net outcome is largely contingent on topographical positions. In poorly drained tundra lowlands, thermokarst-induced water impounding resulted in massive shrub cover loss throughout three decades following fire. In contrast, shrub expansion was significantly enhanced in well-drained upland tundra after fire disturbance, especially in area burned of high severity fire. In unburned tundra, a general increase of shrub cover was detected, driven primarily by warming temperature in the lowland but by increased precipitation in the upland. Overall my research yields new insights into the complex responses of tundra ecosystems to climate and fire-regime changes, and suggests the importance of incorporating such information into earth system models for improving our understanding of land-atmosphere feedback processes.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-08-01The student, Yaping Chen, accepted the attached license on 2020-06-17 at 13:59.The student, Yaping Chen, submitted this Dissertation for approval on 2020-06-17 at 14:01.This Dissertation was approved for publication on 2020-06-24 at 16:07.DSpace SAF Submission Ingestion Package generated from Vireo submission #15453 on 2020-10-02 at 15:49:26Made available in DSpace on 2020-10-07T22:48:07Z (GMT). No. of bitstreams: 3
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Differential Reactivity of Metal Binding Domains of Copper ATPases towards Cisplatin and Colocalization of Copper and Platinum
No full textThe Menkes (MNK) and Wilson (WLN) disease proteins are two P-type ATPases responsible for active Cu efflux. These ATPases are also associated with resistance to cisplatin. In this work, different metal-binding domains (MBDs) of ATPases (9 out of 12 domains) were compared based on their reactivity towards cisplatin. The reaction rates of the MBDs can be largely different; the reaction of MNK6 is about six times faster than that of WLN2. Copper coordination favors the platination of the MBDs to different extents. The rate of platination was generally greater for holo-MBDs than for apo-MBDS (particularly in the case of WLN4 and WLN2); however, it was negligibly affected in the case of MNK6. Interestingly, the platinum binding weakens the CuI coordination, but does not expel the copper ion from MBDs. The latter results nicely explain the inhibitory effect of Cu upon the cisplatin translocation promoted by Cu-ATPases and can help in understanding how copper levels can modulate the sensitivity of cancer cells to platinum chemotherapy
Author Correction: IRE1α-XBP1s pathway promotes prostate cancer by activating c-MYC signaling
No full textSheng X, Nenseth HZ, Qu S, et al. Author Correction: IRE1alpha-XBP1s pathway promotes prostate cancer by activating c-MYC signaling. Nature Communications . 2024;15(1): 6190
"Yi zhuan" "sheng sheng" si xiang yan jiu =: On the Idea of shengsheng in the commentaries of Yi
No full textPh.D.The thesis aims to investigate the idea of Shengsheng (continuous creation) in the Commentaries of Yi and its development in the history of Confucian philosophy. The investigation consists of four parts. The first part starts by discussing the literal meaning of the character Sheng in the oracle bone script and the Chinese bronze inscriptions. It then examines the idea of Shengsheng in the ancient Chinese classics, especially its textual context in the Commentaries of Yi . Accordingly, we will answer the following questions one by one: What is Shengsheng ? How can it actualize? How is the idea adopted by other Pre Qin thoughts? The second part focuses on the understanding of the idea in Han Confucianism. It takes Zhouyi Qianzhaodu and the Zheng Xuan interpretation as illustrative examples. Here we see how another idea Qi has been introduced to interpret Sheng sheng as the origin and process of actualization in both the natural world and human community. The third part moves to the development of the idea in Northern Song Confucianism and explores how the Confucian scholars at that time further elaborated the idea as an essential of moral metaphysics. The final part studies the thought of Xiong Shili to show how Xiong draws from Buddhism and Confucian philosophy to develop a critical inquiry into the idea and hence argues its modern relevance.本文以《易傳》「生生」觀念為研究對象。全文分為四部分，第一部分由考察甲骨、金文中「生」字之原義開始，依次分析並討論了早期文獻中所見之「生生」觀念及《易傳》所論「生生」之本義，包括何為《易傳》所論之「生生」，據《易傳》之說 ，「 生生」將何以實現，以及《易傳》「生生」觀念與先秦諸子思想之關係。第二部分通過以《周易乾鑿度》為切入點，考察了經學時代下學者們對《易傳》「生生」觀念的最有代表性的若干理解，包括據《乾鑿度》之理解 ，「 生生」當如何實現於天地萬物及人類社會之中，以及鄭康成所作之《乾鑿度注》之中包含的對「生生」 所以實現之根本與歷程的另一種思考。第三部分通過將北宋五子的詮釋作為典範，考察了理學思維下《易傳》「生生」觀念之詮釋理論的一般理論框架，包括理學思維下的「生生」之本質及「生生」之道德義之豁顯。第四部分則通過將熊十力《新唯識論（語體文本）》中關於《易傳》「生生」觀之詮釋作為代表，考察了現代哲學視域下的《易傳》「生生」觀念。竇晨光."2019年8月".Parallel title from added title page.Thesis Ph.D. Chinese University of Hong Kong 2019.Includes bibliographical references (leaves 334-340).Abstracts in Chinese and English.Title from PDF title page (viewed on February 23, 2022).Dou Chenguang
A Study of Chin Sheng-Tan\ue2s Hermeneutics on Du Fu's Poetics
No full textThe thesis mainly discusses the hermeneutic system on Du Fu\ue2s poetics, which was established after close analysis of Du Fu\ue2s poetry by a literary critic Chin Sheng-Tang (the end of the Ming and beginning of the Qing dynasties).Among all Tang poets Chin Sheng-Tang admired Du Fu the most for his poetics of seven line stanzas, which was viewed by Chin Sheng-Tang as an epitome of high aesthetical value and poetical canon. The critic proposed a method of decompositional analysis for studying Du Fu\ue2s poetry: he saw the interconnection between the title of the poem and it\ue2s content, and then decomposed the poem into small pieces, conducting close reading, so that the poem was seen as having three level structure from bigger to smaller \ue2the level of passages, sentences and characters\ue2.
First, we start with looking at \ue2other interpretation\ue2 from the describing trend of hermeneutics on Du Fu\ue2s poetics prevailing during that period of time, pointing out what was the main opinion of the literary critics, and comparing it with the one of Chin Sheng-Tang\ue2s, and looking at his status among the circles of literary critics.
Then we discuss the Chin Sheng-Tang \ue2s \ue2self interpretation\ue2 , explaining what kind of reader and critic he was. After that we provide the review of poetry reading methods and horizon in literary criticism, explaining how to use the method in literary analysis. After Chin Sheng-Tang\ue2s method of literary criticism becomes clear to us, we look how his caesura method is used to analyze structure of Du Fu\ue2s poetry. Through the caesura analysis we use reader\ue2s, author\ue2s and literary works point of view to find out whether this method is appropriate and whether it can reveal the spirit of that age or is it simply an over-reading. In the end we provide the conclusion about the effectiveness of the hermeneutic system, proposed by Chin Sheng-Tang
Reduced-rank adaptive least bit-error-rate detection in hybrid direct-sequence time-hopping ultrawide bandwidth systems
No full textDesign of high-efficiency low-complexity detection schemes for ultrawide bandwidth (UWB) systems is highly challenging. This contribution proposes a reduced-rank adaptive multiuser detection (MUD) scheme operated in least bit-errorrate (LBER) principles for the hybrid direct-sequence timehopping UWB (DS-TH UWB) systems. The principal component analysis (PCA)-assisted rank-reduction technique is employed to obtain a detection subspace, where the reduced-rank adaptive LBER-MUD is carried out. The reduced-rank adaptive LBERMUD is free from channel estimation and does not require the knowledge about the number of resolvable multipaths as well as the knowledge about the multipaths’ strength. In this contribution, the BER performance of the hybrid DS-TH UWB systems using the proposed detection scheme is investigated, when assuming communications over UWB channels modeled by the Saleh-Valenzuela (S-V) channel model. Our studies and performance results show that, given a reasonable rank of the detection subspace, the reduced-rank adaptive LBER-MUD is capable of efficiently mitigating the multiuser interference (MUI) and inter-symbol interference (ISI), and achieving the diversity gain promised by the UWB systems
Magnetoresistance in triphenyl-diamine derivative blue organic light emitting devices
No full textCopyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 103, 043706 (2008) and may be found at
High Performance Dye-Sensitized Solar Cells with Enhanced Light-Harvesting Efficiency Based on Polyvinylpyrrolidone-Coated Au-TiO2 Microspheres
No full textSurface plasmon resonance using noble metal nanoparticles is regarded as an attractive and viable strategy to improve the optical absorption and/or photocurrent in dye-sensitized solar cells (DSSCs). However, no significant improvement in device performance has been observed. The bottleneck is the stability of the noble-metal nanoparticles caused by chemical corrosion. Here, we propose a simple method to synthesize high-performance DSSCs based on polyvinylpyrrolidone-coated Au-TiO2 microspheres that utilize the merits of TiO2 microspheres and promote the coupling of surface plasmons with visible light. When 0.4wt% Au nanoparticles were embedded into the TiO2 microspheres, the device achieved a power conversion efficiency (PCE) as high as 10.49%, a 7.9% increase compared with pure TiO2 microsphere-based devices. Simulation results theoretically confirmed that the improvement of the PCE is caused by the enhancement of the absorption cross-section of dye molecules and photocurrent
APHERP symposium session II: Institutional management
No full textPresented Titles: Japan’s Responses to the Pandemic in Higher Education [Author: Futao Huang] Financing Higher Education in a Post-COVID Era [Author: Deane E. Neubauer] Who Influences Higher Education Decision-making in Taiwan? An Analysis of Internal Stakeholders [Authors: Sheng-ju Chan; Prudence Chuing Chou] COVID-19, Communities and Change [Author: Peter Duffy
Organizational Form and the Economic Impact of Corporate New Product Strategies
No full textThis paper examines the role of organizational form in explaining the economic impact of corporate new product strategies. I find that the wealth effects associated with the announcements of new product introductions are more favorable for introducing firms with focused activities than for those with diversified activities. The results hold even after controlling for other factors suggested in the literature that could affect the value of new product introductions. The findings in this study suggest that the efficient investment hypothesis dominates the internal capital markets hypothesis in terms of the net economic impact of new product introductions on the introducing firms. Copyright 2007 The Author Journal compilation (c) 2007 Blackwell Publishing Ltd.
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