59 research outputs found
Selection and Performance Analysis of Asia-Pacific Hedge Funds
This paper studies portfolio selection and performance analysis of hedge funds whose locations or investment targets are Asian-Pacific region. Utilizing Eurekahedge database, we investigate the characteristics of the funds' returns and optimization methods to create a fund of funds. Moreover, we decompose the returns of the hedge funds into risk factors which are observable in financial markets such as stock indices. Then, we attempt to manage a fund of funds by applicating those analyses.
On the concept of “Comprehensiveness” in Information Services: The case of the online translation aid and hosting service Minna no Hon'yaku / Kyo Kageura and Takeshi Abekawa
The aim of this research is to clarify the concept of ―comprehensiveness‖ and its relationship to the concept of ―normativeness‖ in language reference tools and information for online translators, from the point of view of strategically providing useful reference information via a translation aid-service. The concept of ―comprehensiveness‖ in reference information has not been explored fully to dateThe questions to be answered are: What are the factors that determine different levels of ―comprehensiveness‖ and ―normativeness‖? How can ―comprehensiveness‖ be classified in relation to different types of reference lookup, and what kind of strategies can we define and adopt in developing and providing useful reference resources automatically or semi-automatically? While it is widely held that careful user studies are important in the strategic design of information services, empirical studies of potential users are not sufficient in the conceptualisation and development of advanced information services and tools which incorporate innovative functions or features, because quite frequently users do not understand what they want from the new information technologies. This is all the more true for issues in which one or more of the key concepts are not understood clearly. The question we wished to address fall precisely within this category, as the concept of ―comprehensiveness‖ has not yet been explored fully. We therefore took a deductive and analytical approach, firstly listing up the factors that affect the concept of ―comprehensiveness‖ and related concepts, with special reference to the translation-aid site Minna no Hon'yaku (translation of/by/for all: http://trans-aid.jp/), and deriving the classification of and desiderata for language reference tools and information from the objective of helping online translators. Although we adopted an analytical and deductive approach, the whole argument is implicitly supported by our own experience with actual translators' behaviour on the site Minna no Hon'yaku. Results of the analysis revealed that, within a framework of providing language reference tools for translators in general and in the context of the online translation-aid environment in particular, three different types of combinations of ―comprehensiveness‖ and ―normativeness‖ are of prominence and importance, namely: (i) task-oriented normativeness/comprehensiveness; (ii) domain-oriented normativeness/comprehensiveness; and (iii) user-oriented normativeness/comprehensivenes
The double-stranded break-forming activity of plant SPO11s and a novel rice SPO11 revealed by a Drosophila bioassay
<p>Abstract</p> <p>Background</p> <p>SPO11 is a key protein for promoting meiotic recombination, by generating chromatin locus- and timing-specific DNA double-strand breaks (DSBs). The DSB activity of SPO11 was shown by genetic analyses, but whether SPO11 exerts DSB-forming activity by itself is still an unanswered question. DSB formation by SPO11 has not been detected by biochemical means, probably because of a lack of proper protein-folding, posttranslational modifications, and/or specific SPO11-interacting proteins required for this activity. In addition, plants have multiple SPO11-homologues.</p> <p>Results</p> <p>To determine whether SPO11 can cleave DNA by itself, and to identify which plant SPO11 homologue cleaves DNA, we developed a <it>Drosophila </it>bioassay system that detects the DSB signals generated by a plant SPO11 homologue expressed ectopically. We cytologically and genetically demonstrated the DSB activities of <it>Arabidopsis </it>AtSPO11-1 and AtSPO11-2, which are required for meiosis, in the absence of other plant proteins. Using this bioassay, we further found that a novel SPO11-homologue, OsSPO11D, which has no counterpart in <it>Arabidopsis</it>, displays prominent DSB-forming activity. Quantitative analyses of the rice SPO11 transcripts revealed the specific increase in OsSPO11D mRNA in the anthers containing meiotic pollen mother cells.</p> <p>Conclusions</p> <p>The <it>Drosophila </it>bioassay system successfully demonstrated that some plant SPO11 orthologues have intrinsic DSB activities. Furthermore, we identified a novel SPO11 homologue, OsSPO11D, with robust DSB activity and a possible meiotic function.</p
A coherent Ising machine for 2000-node optimization problems
The analysis and optimization of complex systems can be reduced to mathematical problems collectively known as combinatorial optimization. Many such problems can be mapped onto ground-state search problems of the Ising model, and various artificial spin systems are now emerging as promising approaches. However, physical Ising machines have suffered from limited numbers of spin-spin couplings because of implementations based on localized spins, resulting in severe scalability problems. We report a 2000-spin network with all-to-all spin-spin couplings. Using a measurement and feedback scheme, we coupled time-multiplexed degenerate optical parametric oscillators to implement maximum cut problems on arbitrary graph topologies with up to 2000 nodes. Our coherent Ising machine outperformed simulated annealing in terms of accuracy and computation time for a 2000-node complete graph
Visualization of intrathoracically disseminated solid tumors in mice with optical imaging by telomerase-specific amplification of a transferred green fluorescent protein gene
Currently available methods for detection of tumors in vivo such as X-ray, computed tomography, and ultrasonography are noninvasive and have been well studied; the images, however, are not specific for tumors. Direct optical imaging of tumor cells in vivo that can clearly distinguish them from surrounding normal tissues may be clinically useful. Here, we describe a new approach to visualizing tumors whose fluorescence can be detected using tumor-specific replication-competent adenovirus (OBP-301, Telomelysin) in combination with Ad-GFP, a replication-deficient adenovirus expressing green fluorescent protein (GFP). Human telomerase reverse transcriptase is the catalytic subunit of telomerase, which is highly active in cancer cells but quiescent in most normal somatic cells. We constructed an adenovirus 5 vector in which the human telomerase reverse transcriptase promoter element drives expression of E1A and E1B genes linked with an internal ribosome entry site and showed that OBP-301 replicated efficiently in human cancer cells, but not in normal cells such as human fibroblasts. When the human lung and colon cancer cell lines were infected with Ad-GFP at a low multiplicity of infection, GFP expression could not be detected under a fluorescence microscope; in the presence of OBP-301, however, Ad-GFP replicated in these tumor cells and showed strong green signals. In contrast, coinfection with OBP-301 and Ad-GFP did not show any signals in normal cells such as fibroblasts and vascular endothelial cells. We also found that established subcutaneous tumors could be visualized after intraturnoral injection of OBP-301 and Ad-GFP. A549 human lung tumors and SW620 human colon tumors transplanted into BALB/c nu/nu mice were intraturnorally injected with 8 X 10(5) plaque-forming units of Ad-GFP in combination with 8 X 106 plaque-forming units of OBP-301. Within 3 days of treatment, the fluorescence of the expressed GFP became visible by a three-chip color cooled charged-coupled device camera in these tumors, whereas intraturnoral injection of Ad-GFP alone could not induce GFP fluorescence. Moreover, intrathoracic administration of Ad-GFP and OBP-301 could visualize disseminated A549 tumor nodules in mice after intrathoracic implantation. Our results indicate that intratumoral or intrathoracic injection of Ad-GFP in combination with OBP-301 might be a useful diagnostic method that provides a foundation for future clinical application
Status Report of Neutral Kaon photo-production study using Neutral Kaon Spectrometer 2 (NKS2) at LNS-Tohoku(I. Nuclear Physics)
Status Report of Neutral Kaon photo-production study using Neutral Kaon Spectrometer 2 (NKS2) at LNS-Tohoku(I. Nuclear Physics)
The approach described in this paper uses an array of Field
Programmable Gate Array (FPGA) devices to implement a fault tolerant hardware system that can be compared to the running of fault tolerant software on a traditional processor. Fault tolerance is achieved is achieved by using FPGA with on the fly partial programmability feature. Major considerations while mapping to the FPGA includes the size of the area to be mapped and communication issues related to their communication. Area size selection is compared to the page size selection in Operating System Design. Communication issues between modules are compared to the software engineering paradigms dealing with module coupling, fan-in, fan-out and cohesiveness. Finally, the overhead associated with the downloading of the reconfiguration files is discussed
A coherent Ising machine for 2000-node optimization problems
The analysis and optimization of complex systems can be reduced to mathematical problems collectively known as combinatorial optimization. Many such problems can be mapped onto ground-state search problems of the Ising model, and various artificial spin systems are now emerging as promising approaches. However, physical Ising machines have suffered from limited numbers of spin-spin couplings because of implementations based on localized spins, resulting in severe scalability problems. We report a 2000-spin network with all-to-all spin-spin couplings. Using a measurement and feedback scheme, we coupled time-multiplexed degenerate optical parametric oscillators to implement maximum cut problems on arbitrary graph topologies with up to 2000 nodes. Our coherent Ising machine outperformed simulated annealing in terms of accuracy and computation time for a 2000-node complete graph
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