1,192 research outputs found
Impact of large-scale activities on macroscopic fundamental diagram: Field data analysis and modeling
No full textLarge-scale activities always have serious impacts on regional traffic states. It is necessary for traffic planners to investigate the characteristics of network traffic flow under large-scale activities and apply proper management strategies. In this paper, based on the field data in Tianjin, China, the impact of large-scale activities and the corresponding control strategies on regional Macroscopic Fundamental Diagram (MFD) and regional traffic states are analyzed. The study area is divided into the inner area and the outer area. Based on the work of Haddad (2012) on the traffic perimeter control in two-region, a dynamic model is calibrated by the empirical data in Tianjin to study the influences of activities and control strategies. Based on the calibrated model, different control strategies are simulated to investigate the impacts on regional traffic flow. The results show that decreasing the transfer flow from the outer area will alleviate the congestion in the inner area effectively, and increasing the system outflow will reduce the densities of both two areas effectively. When the traffic states are already congested, the real control strategies cannot alleviate the congestion of the regional network effectively. According to the various impacts of different strategies, combined control strategies are proposed to mitigate the adverse impact of large-scale activities on the surrounding area.This work was partially supported by the National Natural Science Foundation of China (Grant No. 71771012, No. 71961137008, No. 72171018, and No. 71931002). The author would like to thank the anonymous reviewers for their valuable comments on the paper
The sensor of the bacterial histidine kinase CpxA is a novel dimer of extracytoplasmic Per-ARNT-Sim domains
No full textHistidine kinases are key bacterial sensors that recognize diverse environmental stimuli. While mechanisms of phosphorylation and phosphotransfer by cytoplasmic kinase domains are relatively well-characterized, the ways in which extracytoplasmic sensor domains regulate activation remain mysterious. The Cpx envelope stress response is a conserved Gram-negative two-component system which is controlled by the sensor kinase CpxA. We report the structure of the Escherichia coli CpxA sensor domain (CpxA-SD) as a globular Per-ARNT-Sim (PAS)-like fold highly similar to that of Vibrio parahaemolyticus CpxA as determined by X-ray crystallography. Because sensor kinase dimerization is important for signaling, we used AlphaFold2 to model CpxA-SD in the context of its connected transmembrane domains, which yielded a novel dimer of PAS domains possessing a distinct dimer organization compared to previously characterized sensor domains. Gain of function cpxA∗ alleles map to the dimer interface, and mutation of other residues in this region also leads to constitutive activation. CpxA activation can be suppressed by mutations that restore inter-monomer interactions, suggesting that inhibitory interactions between CpxA-SD monomers are the major point of control for CpxA activation and signaling. Searching through hundreds of structural homologs revealed the sensor domain of Pseudomonas aeruginosa sensor kinase PfeS as the only PAS structure in the same novel dimer orientation as CpxA, suggesting that our dimer orientation may be utilized by other extracytoplasmic PAS domains. Overall, our findings provide insight into the diversity of the organization of PAS sensory domains and how they regulate sensor kinase activation
蔣士銓研究
No full text[[abstract]]夫風化流於朝庭者效慢，聲音出於男女者易感，是故輒於世道式微之際，政教
衰怠之時，則人倫之情理多乖，人性之惡習彌彰，由是鄭衛之聲盈耳，雅頌之音靡
聞，而流風所播，致使男女交失其情，毋以忠孝義烈為重者也。因此有識之士，遂
相與起而振發綱常，提倡忠孝，一正人倫，並彰義烈，或登之毯毬，或播諸弦管，
無非為借男女之聲音，以施教化者也。當今之世，其道亦然，若圖秩序人倫，必先
放鄭衛之靡音：而守雅頌之正韻，繼承先哲之遺芬，賡揚昔賢之緒論，則可收振衰
起蔽之功，立懦廉頑之用，而是篇之作，亦此而已。
是篇雖章分十七，要之，不外七部而已。第一部為首章之緒論，敘述當時之文
學背景及發展情形，以觀蔣氏文學之動向，及所受此一文學潮流之影響者也。第二
部為次章中家世交遊年譜性格及思想之分析，則蔣氏個人之德行品格修養，於此實
可概見焉。第三部為藏園九種曲之研究，共分九章，對於每種之作意音律排場及內
容，均有明確之分析。第四部為患雅堂詩文集之研究，共分三章，其有論述者，則
尋繹而討論之，如文論詩論等節是也，若其作品中，有所商議者，則標目而講明之
，如詩之拗律、銅絃詞及南北曲之論音律等節是也。第五部為蔣士銓作品之風格及
特色，則蔣氏之文詩詞曲所為之風格及特色，於焉可見。第六部為批評與影響，則
於蔣氏作品之評價，及影響後世者，實可具見焉。第七部為全文之結論，乃對於蔣
氏畢生之作為而發者也。以上合為七部，分為十七章，乃此篇研究之大概焉。
至於是篇所論，對於蔣氏之作品，俱以均衡之論述，而其中尤以戲曲為主，故
置於文詩詞之先。此外資料之取捨，當以合乎章節為主，而重要者尤居前列，若失
偶有涉及者，則視其旨之所在而論列，否則一概汰焉而不取。又於蔣氏家世小傳，
若其年譜中無法論列者，則一律於小傳詳言之，使人愈見其更多之資料，與恢宏之
議論焉。
且是篇之作，於蔣氏之作品，多所考訂，如文集卷六「武德郎景瞻曾君墓誌銘
」中，云「乙巳秋冬之間，與君聚數月」，按此乙巳應為己巳之誤也，蓋曾君於乾
隆十九年甲戌下世，乙巳則乾隆五十年也，蔣氏亦逝矣，阿得見焉，而己巳適為乾
隆十四年，距曾君之卒，尚有六年，因此而更正之也。又文集卷二「檜門金先生畫
像記」及卷七「左都御史檜門金公行狀」，均載金卒之年月為壬午正月十一日，然
而「詩集序」中，金于壬午臘月，仍為蔣氏序其詩集，且詩集之記載，亦置於是年
之末者，因如金氏非在壬午正月十一日而卒也，或此正月十一日，非農曆之記而為
西曆之詞也。又藏園九種曲，其作成之次序，分別為一片石、空谷香、桂林霜、四
絃秋、雪中人、臨川夢、香祖樓、第二磚及冬青樹也，而朱湘著蔣士銓、及青木氏
之所撰，均以香祖樓先於臨川夢，蓋其等未觀蔣氏之自序者也，其自序云臨川夢成
於上己之日，而香祖樓則成於同年之寒食之日，據此可知其孰先孰後矣。
至從本篇之整體言之，愚於戲曲一門，實多所收益。以曲律言之，蔣氏所撰藏
園九種曲中，除空谷香及冬青樹工譜，尚未為前人所訂正者外，餘均已稽考完備，
故愚取各家之曲譜，而正此二種之曲，加以在講席之間，每接聞有關曲律之論，領
會殊多，蓋曲律與詩詞之律，每有相通之處，若七字句者，一三實可不論，又於每
一音節之前一字，其平八又可勿論者也，如六字句非折腰句者，其一三五音節中之
字，平八方可不論者也。此外仄聲獨用時，去上亦可不分，而去上相聯之律，方可
譜作上去。惟不可譜以平聲而已。至以務頭言之，務頭乃曲中音節極諧美之處，蓋
以七字句中之三四五音節最為婉轉，其餘者較次也，其譜法大抵以陽平陰上陽去，
或陰平陽上陰去，或陰上陽平，或陽上陰平等律而填之，使其陰陽相間，則其音節
自必婉轉諧美者焉。今雖元音已墜，惟於曲中仍能謹守去上之律，別譜曲之能事，
方可畢矣。
綜之，蔣士銓研究一編，雖所論疏漏甚多，然其犖犖之大者，殆無遺焉。
國民中小學體育教師專業態度之調查研究
No full text[[abstract]]本研究採調查研究法，以自編之「體育教師態度問卷」為調查之工具，探求國民中、
小學體育教師專業態度之差異。
調查對象限定台北市國民中、小學體育教師。發出問卷三四五份，收回二七○份，收
回率為七八％，有效卷二二九份（國中一三三份、國小九六份），佔發出卷的六六％
。調查結果所得到的各組分數以平均數計算之，並以t 考驗(t-test)檢定平均數之間
的差異。國中、國小體育教師對問卷各題目反應之差異以卡方(Chi-Square)檢定之。
折半信度和效係數以皮爾遜積差相關法(Pearson's Product-Moment Correlation
Method) 計算，信度係數復以斯布(Spearman-Brown Prophecy Formula) 公式加以校
正。顯著水準定為•○五•○一，重要調查結果顯示如下：
(一)正式調查態度問卷其折半總信度為•九三四，達顯著水準(P<.01) 。
(二)國中體育教師其專業態度與國小體育教師沒有顯著差異(P<.05) 。
(三)國小體育教師專業道德修養優於國中體育教師(P<.05) 。
(四)國中體育教師對於專業知能之認知，優於國小體育教師(P<.01) 。
(五)國中體育教師較國小體育教師更能滿足於體育教學工作(P<.05) 。
(六)受過師範學校體育教育之體育教師專業態度，較受非師範學校體育教育之體育教
師為積極(P<.05)。
(七)師大體育系畢業之國中體育教師專業態度，較二年制體專和三年制體專畢業之國
中體育教師為積極(P<.05) 。五年制體專畢業之國中體育教師專業態度，較三年制體
專畢業之國中體育教師為積極(P<.05) 。
(八)志願且經甄選之國中體育教師專業態度，較志願而未經甄選之國中體育教師為積
極(P<.05) 。
(九)非保送之國中體育教師專業態度，較保送之國中體育教師為積極(P<.05) 。
(十)已婚之國小體育教師專業態度，較未婚之國小體育教師為積極(P<.05) 。
(十一)有擔任行政工作之國中體育教師專業態度，較未擔任行政工作之國中體育教師
為積極(P<.05) 。
(十二)41∼45歲組國中體育教師專業態度，較36∼40歲組之國中體育教師為積極(P<
.05)。26∼30歲組國中體育教師專業態度，較36∼40歲組之國中體育教師為積極(P<
.05)。31∼35歲組國中體育教師專業態度，較36∼40歲組之國中體育教師為積極(P<
.05)。
(十三)31∼35歲組國小體育教師專業態度，較26∼30歲組、36∼40歲組、41∼45歲組
之國小體育教師為積極(P<.05) 。
Fu li qu dong tuan liu zhong de biao liang shu yun ji qu ci xi jun de yun dong xue te xing
No full textPh.D.This thesis consists four parts. The first three parts concern the transport properties in buoyancy-driven flows and the last one studies the kinematic properties of an active matter system.The first one is an experimental and numerical study of natural convection with moist air as convecting fluid. By simplifying the system as two-component convection, an experimental method is developed to indirectly measure the moisture transfer rates in buoyancy-driven flows. The result is verified by direct numerical simulations (DNS). It is found that the nondimensionalized transfer rates for both sensible heat and water vapor are essentially determined by a generalized Grashof number, and are only weakly dependent on the buoyancy ratio. As a special case, the Schmidt number dependence for passive scalar transfer rate in buoyancy driven flows is also deduced. The present result should also complement the existing bulk parameterization models for evaporation in nature.The second study concerns the effect of horizontal buoyancy on heat transport in turbulent thermal convection. A vector formed global heat transport is proposed. For fixed vertical buoyancy, we find that the vertical heat transport increase monotonically with the horizontal buoyancy and the horizontal heat transport is also non-negligible. Our DNS result confirms these experimental findings and highlights the richness in convective transport. We further extend the Grossmann-Lohse theory to the case with both vertical and horizontal buoyancy, which not only describes well the effect of horizontal buoyancy, but also captures the general trend of the Prandtl number dependence.The third part of the thesis is focused on Rayleigh-B\'enard convection in slender geometries. Experimentally, this is realized by 3D-printed parallel channel-like structures. Comparing with the case of unit aspect ratio, increase in the overall heat transport are observed for aspect ratio 1/6 and 1/10, provided the Rayleigh number exceeds certain threshold value. We also identify a transition in the Nusselt-Rayleigh scaling from approximately 3/7 to a value close to 1/4. These results, together with measurements in two similar configurations, reveal that the global heat transport can indeed be enhanced by perturbing the bulk of the flow rather than the thermal boundary layer.In the fourth part we discuss the kinematic behavior of a magnetotactic bacterium, M. magneticum strain AMB-1. A statistical method is developed to quantify the batch-averaged magnetic moment possessed by single AMB-1 cell. Furthermore, the comparison between results from the living and dead AMB-1 cells provides an evidence for the possible existence of an active magnetic response pathway.本論文包含四個部分。前三部分旨在研究浮力驅動湍流系統中的輸運行為，最後一部分則主要探討了活性物質系統中的運動學特性。在第一部分工作中，我們通過實驗及數值方法研究了由濕空氣作為對流介質的自然對流系統。通過將該系統簡化為雙組分對流問題，我們提出了一個從實驗上定量推算浮力驅動對流中水汽輸運效率的方法，其結果被直接數值模擬所證實。我們發現無量綱化的水汽輸運效率以及顯熱輸運效率主要由廣義的格拉斯霍夫數決定。通過考慮極限情況，我們進一步推算并預測了被動標量在浮力驅動湍流中的輸運效率隨施密特數變化的標度律指數。這些結果對現有的估算自然界中水汽蒸發量的參數化模型作出了補充。第二部分工作則系統地討論與研究了水平浮力對傳熱的影響。我們將熱對流系統中的傳熱推廣到了矢量形式。對於給定垂直浮力，我們發現系統的垂向熱輸運效率隨水平浮力單調增長，且系統水平方向的總體熱輸運強度也不可被忽略。直接數值模擬與實驗結果的相符，印證與突出了對流系統中輸運方式的多樣性。我們將著名的格羅斯曼-洛斯理論推廣到了存在水平浮力的情況，其結果不但準確描述了水平浮力對總傳熱的影響，也可以刻畫其對普朗特數的依賴關係。論文的第三部分主要研究了細長幾何結構中對流的熱輸運效率。實驗上，我們利用三維打印技術實現了並聯的薯條狀細長對流槽。與寬高比為一的對照組相比，在超過一定瑞利數閾值的區間，我們在寬高比為六分之一和十分之一的細長對流槽中都測得了顯著提升的總傳熱。與此同時，在兩組實驗中我們都觀察到了努賽爾數對瑞利數標度律從接近3/7向1/4的轉變。在另外兩個相似的幾何結構中，我們也觀察到了傳熱的增加，以上結果揭示了通過改變對流槽中心結構（而不是邊界層）來增加系統總體輸運效率的可能性。在最後一部分工作中，我們研究與討論了趨磁細菌在不同外磁場強度下的運動學行為。我們發展了一個統計上的方法量化并測得了趨磁細菌磁小體的平均磁矩。此外，活細菌與死細菌在運動學特性上的差別，為趨磁細菌可能對磁場存在主動響應的觀點提供了間接證據。Zhang, Lu = 浮力驅動湍流中的標量輸運及趨磁細菌的運動學特性 / 張路.Thesis Ph.D. Chinese University of Hong Kong 2019.Includes bibliographical references (leaves 143-155).Abstracts also in Chinese.Title from PDF title page (viewed on 06, January, 2021).Zhang, Lu = Fu li qu dong tuan liu zhong de biao liang shu yun ji qu ci xi jun de yun dong xue te xing / Zhang Lu
Tunable ZnO surface acoustic wave devices based on acoustoelectric interaction
No full textTunable surface acoustic wave (SAW) devices have been attracting considerable research efforts, as they are highly desired in advanced communication systems by offering versatile signal processing capability. Among various tuning mechanisms, the perturbation of the electrical boundary condition based on the acoustoelectric interaction in a semiconducting/piezoelectric multilayer structure is a promising approach to realize tunable SAW devices with low bias, large tunability, and small device dimension. To reduce the fabrication complexity and enhance the device reliability, the monolithic device structure is preferable.
This dissertation addresses the design and development of the tunable ZnO SAW devices based on the acoustoelectric interaction. Epitaxial ZnO and MgxZn1-xO multilayer structures grown by metal-organic chemical vapor deposition (MOCVD) on r-Al2O3 substrates are used as the basic structure, which offer advantages as high coupling coefficient and multimode SAW generation. The device related processing techniques, including wet chemical and dry etching of ZnO and MgxZn1-xO films, are investigated with respect to the etch rate, etch profile, surface morphology and process induced damage. The maximal 1:1 pattern edge slope has been achieved.
A prototype of ZnO UV SAW device has been demonstrated using semiconducting-piezoelectric ZnO multilayer structure, which enables the wireless output for sensor network. The interaction of the SAW with the UV induced carriers in the semiconducting ZnO layer results in a phase shift and an insertion loss change, as functions of the incident light wavelength and power. A phase shift of 107o is achieved at 365 nm for a light power of 2.32 mW/ cm2.
A prototype of ZnO based voltage controlled multi-mode tunable SAW device has been demonstrated through the integration of a depletion-type MIS structure (Al/SiO2/semiconducting ZnO) and a piezoelectric ZnO/r-Al2O3 system. The acoustic velocity tunability is achieved by changing the sheet conductivity of the semiconducting channel through the gate biasing. Due to the in-plane piezoelectric anisotropy of the ZnO/r-Al2O3 system, the device can be operated with both Sezawa and Love mode for gaseous and liquid sensing, respectively. Under -18 V bias, 420o and 277.3o phase shifts are achieved for Sezawa and Love mode operation, respectively.Ph.D.Includes bibliographical references (p. 142-149)
Social Interaction Effects and Individual Portfolio Choice: Evidence from 401(k) Pension Plan Investors
No full text
ISL-1 is overexpressed in non-Hodgkin lymphoma and promotes lymphoma cell proliferation by forming a p-STAT3/p-c-Jun/ISL-1 complex
No full textBackground: Insulin enhancer binding protein-1 (ISL-1), a LIM-homeodomain transcription factor, is essential for the heart, motor neuron and pancreas development. Recently, ISL-1 has been found in some types of human cancers. However, how ISL-1 exerts the role in tumor development is not clear. Methods and results: The expression of ISL-1 was assessed in 211 human lymphoma samples and 23 normal lymph node samples. Immunohistochemistry results demonstrated a markedly higher expression of ISL-1 in 75% of non-Hodgkin lymphoma (NHL) samples compared with that in normal lymph nodes or Hodgkin lymphoma (HL) samples. CCK-8 analysis, cell cycle assay and xenograft model were performed to characterize the association between ISL-1 expression level and biological functions in NHL. The results showed that ISL-1 overexpression obviously promoted NHL cells proliferation, changed the cell cycle distribution in vitro and significantly enhanced xenografted lymphoma development in vivo. Real-time PCR, Western blot, luciferase assay and ChIP assay were used to explore the potential regulatory targets of ISL-1 and the results demonstrated that ISL-1 activated the c-Myc expression in NHL by direct binding to a conserved binding site on the c-Myc enhancer. Further results revealed that ISL-1 could be positively regulated by the c-Jun N-terminal kinase (JNK) and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways. Both the JNK and JAK/STAT signaling inhibitors could significantly suppressed the growth of NHL cells through the down-regulation of ISL-1 as demonstrated by CCK-8 and Western blot assays. Bioinformatic analysis and luciferase assay exhibited that ISL-1 was a novel target of p-STAT3 and p-c-jun. ChIP, Co-IP and ChIP-re-IP analysis revealed that ISL-1 could participate with p-STAT3 and p-c-Jun to form a p-STAT3/p-c-Jun/ISL-1 transcriptional complex that binds directly on the ISL-1 promoter, demonstrating a positive feedback regulatory mechanism for ISL-1 expression in NHL. Conclusions: Our results provide the first evidence that ISL-1 is tightly linked to NHL proliferation and development by promoting c-Myc transcription, and its aberrant expression was regulated by p-STAT3/p-c-Jun/ISL-1 complex activation.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000339918900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Biochemistry & Molecular BiologyOncologySCI(E)[email protected]; [email protected]
Robust Manipulation of Magnetism in Dilute MagneticSemiconductor (Ga,Mn)As by Organic Molecules
No full text- …
