1,721,079 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Mechanisms for repressing DNA replication by Ndt80
No full text在出芽酵母菌(Saccharomyces cerevisiae)中，Ndt80是一個在減數分裂時特定表現的轉錄因子(transcriptional activator)，它能夠誘導減數分裂中期基因的表現。有趣的是，在營養細胞中異位表現 (ectopic expression) Ndt80會造成細胞生長週期停滯在G1/S時期。由這樣的結果可推測，或許Ndt80能夠抑制第一次減數分裂(meiosis I)和第二次減數分裂(meiosis II)中間發生另一次DNA複製，使得細胞能夠成功地產生單倍體的孢子。Ndt80抑制DNA複製也許是透過誘導B-type cyclins基因或其他調控細胞週期進行的基因的表現，或者是經由Ndt80本身直接地結合在DNA的複製起始點上。
為了區別這兩種可能性，我們構築一系列的Ndt80片段缺失突變株(in-frame deletions)，其缺失的區域分別在DNA結合區 (DNA-binding domain)或活化轉錄區 (transcription-activation domain)。將這些突變株於營養細胞中進行異位表現，測試這些突變是否會影響NDT80在營養細胞表現時造成的細胞生長停滯。結果發現Ndt80的DNA結合區對於造成G1/S時期的生長停滯是必要的；另一方面，Ndt80的活化轉錄區對於造成生長停滯並不是絕對地需要。此外，在B-type cyclins缺失的細胞中異位表現 NDT80仍然能夠造成細胞生長週期停滯在G1/S時期，顯示抑制DNA複製的機制似乎不是透過誘導Ndt80調控的基因。然而，利用染色質免疫沉澱分析(chromatin immunoprecipitation assay)無法提供證據證明Ndt80能夠直接地與DNA複製起始點結合。
另外，在這些片段缺失突變株中，我們發現一個有趣的突變，ndt80∆404-503。利用減數分裂時間曲線的分析以及更進一步的片段缺失分析，我們推測ndt80∆404-503是一個特別且功能可區別的NDT80突變株，它喪失了抑制DNA複製的功能，但仍保有部分活化轉錄的功能。In Saccharomyces cerevisiae, Ndt80 is a meiosis-specific transcriptional activator that binds to the promoter element termed MSE (middle sporulation element) and induces expression of middle sporulation genes. Interestingly, ectopic expression of NDT80 in vegetative cells causes cell cycle arrest at the G1/S phase. It is possible that Ndt80 may repress another round of DNA replication between meiosis I and meiosis II, thus to successfully produce haploid spores. Repression of DNA replication by Ndt80 could be due to the induction of B-type cyclins or other unidentified genes that regulate cell cycle progression. Alternatively, it could be directly due to the binding of Ndt80 itself to the origins of DNA replication.
To distinguish between these two possibilities, we have constructed a series of in-frame deletions in the DNA-binding domain or the transcription-activation domain of Ndt80 and tested for their effects on cell cycle arrest. The results showed that the DNA-binding domain is essential for the repression at G1/S. On the other hand, the transcription-activation domain is not absolutely required for the cell cycle arrest. Furthermore, ectopic expression of NDT80 in null mutants of B-type cyclins still causes G1/S arrest, suggesting that the induction of Ndt80-regulated genes is unlikely to be the repression mechanism. However, the chromatin immunoprecipitation assays did not provide evidence for physical associations between Ndt80 and the origins of DNA replication for the direct mechanism.
Additionally, among these deletion mutations, we have isolated an interesting one, ndt80∆404-503. Based on meiotic time course analyses and further deletion analyses, we suggest that ndt80∆404-503 is a special separation-of-function mutation of NDT80 that loses the ability in repression of DNA replication but retains partial function in transcription activation.ABSTRACT ................................................i
中文摘要 ...............................................ii
TABLE OF CONTENTS .....................................iii
LIST OF TABLES .........................................vi
LIST OF FIGURES .......................................vii
CHAPTER 1. INTRODUCTION .................................1
Meiosis Overview .......................................1
Cell Cycle Control of DNA Replication ..................2
1. Initiation of DNA replication in mitotic cells .....2
The origins of DNA replication .....................2
Pre-replicative complex (pre-RC) ...................3
Kinases controlling the transition to replication ..3
2. Pre-meiotic S phase ................................4
3. The control of once and only once DNA replication
per cell cycle .....................................5
NDT80 .................................................6
Specific aims .........................................9
CHAPTER 2. MATERIALS AND METHODS .......................10
Strains, Media, and Genetic Methods ...................10
Molecular Biology Methods .............................10
General methods .......................................10
Construction of NDT80 in-frame deletions ..............11
Construction of pGAL-ndt80 ............................12
Disruption of B-type cyclins ..........................13
Time Course Analyses ..................................14
Meiotic time course analysis ..........................14
Growth analysis for galactose induction ...............14
Chromatin Immunoprecipitation (ChIP) ..................15
CHAPTER 3. RESULTS .....................................16
I. The Mechanism of Cell Cycle Arrest by Ectopic
Expression of NDT80 ................................16
The transcription-activation domain is not required
for the cell cycle arrest by Ndt80 ...................16
The functions of Ndt80 on repressing DNA replication
and promoting sporulation could be separated .........18
Ndt80-induced cell cycle arrest does not depends
on B-type cyclins ....................................19
ChIP assays did not detect the associations of Ndt80
with the origins of DNA replication ..................20
II. The Analysis of ndt80∆404-503 .....................21
ndt80∆404-503 is proficient in sporulation but
loses the activity to cause cell cycle arrest ........21
Time course analyses of ndt80∆404-503 ................21
Construction of more subtle deletions of Ndt80 .......22
CHAPTER 4. DISCUSSION ..................................24
I. Mechanisms for Repressing DNA Replication
by Ndt80 ...........................................24
The DNA-binding domain of Ndt80 is essential for
Ndt80-induced cell cycle arrest, while the
transcription-activation domain is not absolutely
required .............................................24
Ndt80 may directly bind the replication origins
or the other sequences in the yeast genome to
repress DNA replication ..............................25
Ndt80 may repress DNA replication through an
indirect mechanism by distinct domains that are
different from promoting sporulation .................26
II. The Effects of ndt80∆404-503 ......................27
The deletion of residues 404-503 may lead to a
conformational change in Ndt80 that affects its
ability to repress DNA replication ...................27
The progression in the accumulations of the
tetranucleated cells and asci seems to be slightly
delayed in ndt80 BR2495 strain overexpressing
ndt80∆404-503 ........................................28
The region between the DNA binding domain and the
transcription-activation domain might be critical
in the regulation of Ndt80 protein function ..........29
III. The Functions of Ndt80 on Meiotic Cell Cycle .....30
Ndt80 may have other functions in meiosis, in
addition to transcription activation .................30
Similarities between Ndt80 and other multifunctional
transcription factors ................................30
REFERENCES .............................................33
TABLES .................................................41
FIGURES ................................................48
APPENDIX ...............................................5
Cache-aware task scheduling for multi-core architectures
No full text隨著製程的進步,多核心處理器已經成為實現高效能處理器的一主要方向。在多核心處理器的架構中，每一個處理核心(processor core)可以配有一獨立的私有快取記憶體(private cache)，而多個處理核心更可以同時分享一大型的快取記憶體。由於整體系統的執行效能和快取記憶體的工作效率有著高度的關聯性，最佳化資料的存取模式將可以提升系統的效能，而一經過良好設計的工作排程(task scheduling)將能有效的達成此一目標。然而，多核心系統上的快取記憶體組織的高複雜度增加了以人工方式來最佳化工作排程的困難度。因此，開發一個良好的自動化工作排程最佳化工具是有其必要性的。這篇論文當中，我們試著提出一新工作排程策略，其考慮以增進快取記憶體依存性(cache affinity)，減少記憶體用量(memory footprint)及同步流量(coherence traffic)的方式來減少快取記憶體上的容量失誤(capacity miss)及同步失誤(coherence miss)，進而提升快取記憶體的工作效率。我們並將此一策略實現於一平行程式模組,Threading Building Blocks,的工作排程器中。程式開發者可以透過應用程式介面(application programming interface)來給定每一工作之資料使用大小及分享關係。實驗結果顯示，相較於其他工作排程策略，我們所提出的工作排程策略可以有效的減少程式執行時間，達到較高的系統效能。As the technology shrink and the increasing of the number of transistors on a single chip, multi-core processors have become major implementations to build high-performance processors. In multi-core processors, the processing cores may have separate private caches and/or share a large common cache. Since the system performance highly depends on the cache utilization, the data access pattern should be optimized to improve performance. A good task scheduling is an effective way to optimize data access pattern. However,he cache organizations of multi-core systems are quite complex and it is hard to optimize the scheduling manually. Therefore, a good tool is required. In this paper, we try to minimize capacity and coherence misses through affinity improvement, footprint reduction and coherence traffic minimization. We propose a scheduling policy which integrates these techniques to reduce cache misses effectively. We also implement the policy in the scheduler of a parallel programming model, Thread Building Blocks(TBB). Programmers can specify the footprint and sharing group of each task through API provided by TBB easily, and the scheduler would optimize the cache utilization accordingly. We believe that this tool can ease the programming complexity by hiding the details for cache utilization optimization to provide high performance.Abstract i Introduction 1.1 Overview of this Thesis...................... 5.2 Organization of this Thesis.................... 6 Related Works 8.1 Maximize data reuse ....................... 8.2 Minimize memory footprint ................... 12.3 Minimize data sharing overhead................. 14 Cache Performance Consideration in CMP 17.1 Data Reuse ............................ 17.2 Memory Footprint ........................ 20.3 Coherence ............................. 23 Cache-Aware Task Scheduling Policy 26.1 Optimize private cache performance............... 27.2 Optimize shared cache performance............... 28.3 Optimize both private and shared cache performance ..... 31 Implement Cache-Aware Task Scheduling Policy 35.1 Threading Building Blocks.................... 35.2 Target Parallel Programming Model............... 38.3 Detail Algorithm ......................... 40 Experimental Results and Evaluation 45.1 Experimental Setup........................ 45.2 Evaluation............................. 48.2.1 Experimental Results on Intel Q9300.......... 49.2.2 Experimental Results on Inteli7............. 53 Conclusion 56ibliography 5
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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