646 research outputs found

    No-scanning 3D measurement method using ultrafast dimensional conversion with a chirped optical frequency comb

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    A simultaneously high-precision, wide-range, and ultrafast time-resolution one-shot 3D shape measurement method is presented. Simultaneous times of flight from multiple positions to a target encoded in a chirped optical frequency comb can be obtained from spectral interferometry. We experimentally demonstrate a one-shot imaging profile measurement of a known step height of 480 µm with µm-level accuracy. We further demonstrate the extension of the dynamic range by measuring in one shot a large step height of 3 m while maintaining high accuracy using the accurate pulse-to-pulse separation of the optical frequency comb. The proposed method with its large dynamic range and measurement versatility can be applied to a broad range of applications, including microscopic structures, objects with large size or aspect ratio, and ultrafast time-resolved imaging. This study provides a powerful and versatile tool for 3D measurement, where various ranges of measurement performances can be tailored to demand

    Stochastic Bargaining Theory and Order Flow

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    This thesis is composed of two parts, each of which reflects our attempt to describe order flow determinants in a bilateral and multilateral trading environment, respectively. In Part I of this research, we investigate noncooperative bilateral sequential bargaining games in which the value of the asset changes stochastically according to a sequence of perfectly observable time-varying random variables. We attempt to model scientific speculations of the game participants that lead to varied length of bargaining durations. Previous studies, which have focused on the analyses of incomplete information games in interpreting bargaining delays, have shown that such delays are attributed to information asymmetry on asset values among players that results in differences in players' personal valuation of the asset. However, following the viewpoint of the Efficient Market Hypothesis, we assume in our models that there is no uneven assimilation of information of vital importance that affects the asset value once the players are at a negotiating table. Hence, one of the important features of the investigated models is that both players observe identical information regarding the future asset value, and that there is no uncertainty regarding one's opponent's preferences during the bargaining process. Despite the assumption of complete information, we argue that a delay before an agreement under certain conditions is an inevitable consequence of the stochastic component in this model. We give game theoretic specifications for two types of bargaining games, which we call the Basic game and the Alternative game. The two games differ from each other in their timing of information arrivals with respect to players' actions. We characterize their subgame perfect equilibria that follow our particular behavioral assumptions. Characteristics of the equilibrium outcomes of the two games are compared. We direct special attention to the study of the analytical results in comparison with those of Rubinstein (1982), Osborne and Rubinstein (1990), and Merlo and Wilson (1995). We then give statistical specifications for two types of stochastic bargaining simulations, which are the Autoregressive Binomial Model and the Generalized Wiener Process Model. Comparative statics of several variables and bargaining durations are investigated thoroughly through numerous simulation runs. Subsequently, through our research we clarify the importance of integrating stochastic concepts into the bargaining theory and its applications in search of alternative explanations for various bargaining durations. In Part II of this research, we provide a set of experimental results in our study of order flow determinants in experimental financial markets with asymmetrically informed human subjects. The markets are organized as computerized double auctions accommodated with an order book that contains a complete set of current limit and market orders and that can be inspected by every market participant at any time during each trading period. Our empirical analysis focuses on the series of actions taken by the subjects that include quote revisions, limit order arrivals, and trades. At first, we report thorough descriptive statistics on the extracted data sets, where we do not assume any particular theory of the market microstructure. Then we show serial dependencies of order flow on the previous event type, the state of the order book, the size of bid-ask spread, and the time intervals. In so doing, we ascertain the significance of the impact of information carried in the order book.</p

    Cell Tropism and Pathogenesis of Measles Virus in Monkeys

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    Measles virus (MV) is an enveloped negative strand RNA virus belonging to the family of Paramyxoviridae, genus Morbillivirus, and causes one of the most contagious diseases in humans. Experimentally infected non-human primates are used as animal models for studies of the pathogenesis of human measles. We established a reverse genetics system based on a highly pathogenic wild-type MV. Infection of monkeys with recombinant MV strains generated by reverse genetics enabled analysis of the molecular basis of MV pathogenesis. The essential in vivo function of accessory genes was indicated by infecting monkeys with recombinant MV strains deficient in the expression of accessory genes. Furthermore, recombinant wild-type MV strains expressing enhanced green fluorescent protein enabled visual tracking of MV-infected cells in vitro and in vivo. To date, three different molecules have been identified as receptors for MV. Signaling lymphocyte activation molecule (SLAM, also called CD150), expressed on immune cells, is a major receptor for MV. CD46, ubiquitously expressed in all nucleated cells in humans and monkeys, is a receptor for vaccine and laboratory-adapted strains of MV. The newly identified nectin-4 (also called poliovirus-receptor-like-4) is an epithelial cell receptor for MV. However, recent findings have indicated that CD46 acts as an MV receptor in vitro but not in vivo. The impact of the receptor usage of MV in vivo on the disease outcome is now under investigation

    Homer/vesl proteins and their roles in CNS neurons

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    Since their initial discovery in 1997, Homer/Vesl proteins have become increasingly investigated as putative regulators of receptor and ion-channel function in the central nervous system. Within a relatively brief period, numerous research reports have described manifold effects of Homer proteins, including the modulation of the trafficking of type I metabotropic glutamate receptors (mGluRs), axonal pathfinding, mGluR coupling to calcium and potassium channels, agonist-independent mGluR activity, ryanodine receptor regulation, locomotor activity, and behavioral plasticity. This review summarizes our current knowledge on the induction, expression, and structure of the various forms of Homer proteins, as well as their roles in neuronal function. In addition, we provide an outlook on novel developments with regard to the involvement of Homer-1a in hippocampal synaptic functio

    High-resolution 3D imaging method using chirped optical frequency combs based on convolution analysis of the spectral interference fringe

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    We applied an imaging optical system and convolution analysis to a one-shot 3D imaging method with a chirped optical frequency comb to greatly improve the transverse spatial resolution and depth accuracy. We obtained the high contrast spectral interference of a diffusive surface using the designed lens system and developed a simple and robust analysis technique using convolution of an obtained the interference fringe. The developed method was demonstrated to realize submicron-level uncertainty for the depth measurement. When applied to the surface structure of a coin, it demonstrated a transverse spatial resolution of 8.98 lp/mm and depth resolution of 0.35 µm

    Management of deep neck infection by a transnasal approach: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Deep neck infection is a life-threatening condition, and intravenous antibiotic therapy is preferable in the early stages of the disease. However, in the advanced stages, surgical drainage should be performed. Although several surgical treatment strategies are available, it is necessary to standardize treatment according to the patient's general condition and history.</p> <p>Case presentation</p> <p>We report the case of a 68-year-old man with a deep neck abscess and with severe diabetes mellitus and inflammation. Computed tomography identified a deep neck infection extending from the level of the epipharynx to that of the hyoid bone. We performed surgical drainage by transnasal endoscopy. The patient exhibited no evidence of either recurrent disease or post-surgical complications within 30 months of follow-up.</p> <p>Conclusions</p> <p>This case report provides evidence that transnasal endoscopic drainage should be recommended as a standard approach in patients with a deep neck abscess and with a severe general condition, diabetes mellitus, and inflammation.</p

    ROLE OF TAXI SUBSIDY SCHEME AS PUBLIC SERVICE FOR MOBILITY OF ELDERLY PEOPLE IN RURAL AREAS OF JAPAN

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    Public transportation in rural areas faces increasing challenges with increasingly aging populations. The elderly and disabled people who cannot drive by themselves highly rely on public transport for traveling. Therefore, to ensure the mobility needs for individual door-to-door services in depopulated areas with dispersed populations, several local authorities in Japan are implementing the taxi subsidy scheme (TSS) for the elderly. However, during the implementation, many issues relating to this policy, such as subsidy amount, usage time and number of distributed tickets, settings for target persons, and target area have been encountered. Based on this fact, we examined TSS from three perspectives: the local government that supports the policy with subsidy; small- and medium-sized taxi operators whose business management is influenced by TSS; and the elderly people with their outing status and TSS usage status. Furthermore, based on the trends of national policies, we examined the effective utilization of TSS as a public mobility service for the elderly in rural areas. As a result, for local governments, the TSS was found to be widely known as a support for vulnerable groups and for those who have returned their licenses, and the burden on residents is often not a large expense. From the viewpoint of taxi operators, TSS has considerably contributed to business management. Additionally, many business operators want to increase the usage time and number of people eligible for subsidies. The elderly survey showed that TSS users use taxi for various purposes and are less likely to be influenced by high prices compared with non-TSS users. In other words, it is suggested that the TSS should be the “ideal public transportation” by narrowing down the target users and improving the service

    A pediatric case of pancreaticobiliary maljunction demonstrated by endoscopic ultrasonography

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    AbstractPancreaticobiliary maljunction (PBM) is a congenital anomaly defined as a junction of the pancreatic and bile ducts located outside the duodenal wall, usually forming a markedly long common channel. Diagnosis of PBM in children is usually made by magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP). Endoscopic ultrasonography (EUS) is a high-resolution imaging modality and a well-established diagnostic tool in adults with pancreaticobiliary (PB) disease. There are several articles which report the value of EUS in the diagnosis and evaluation of PBM in adults, but there are no reports of PBM demonstrated by EUS in children. Here, we present a case of PBM in a pediatric patient that was clearly demonstrated by EUS. EUS can be used as a second line examination modality for demonstrating PBM in pediatric patients in whom first line examinations, such as MRCP or ERCP, cannot be carried out or have not been conclusive
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