245 research outputs found

    "Voluntarily Separable Prisoner's Dilemma with Reference Letters"

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    We consider voluntarily separable repeated Prisoner's Dilemma in which a pair of players meet randomly and repeatedly play Prisoner's Dilemma only by mutual agreement. Fujiwara-Greve and Okuno-Fujiwara (2007) consider the case that once a partnership is dissolved there is no information flow to other partnerships. We consider the case that players can issue a reference letter to the partner if they entered cooperation periods, but the content of a letter is not verifiable. We show that the sheer existence of a letter shortens the trust-building periods of new matches and thus improves efficiency in equilibrium.

    The Role of Expectation in Job Search and Firm Size Effect on Wages

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    One of the most puzzling facts in economics is the firm size-wage effect. After controlling for the observable characteristics of workers (age, gender, education, residence etc.), firms (industry, occupation, work conditions etc.) and negotiation effect (unionization), one still finds that the sheer size of a firm increases the wage, contrary to the one-good one-price doctrine. We provide a simple dynamic game model of wage determination to give a new rationale to the firm size-wage effect. We think that the wages are not market clearing prices but strategies by firms. Firms choose wages to control workers' search behavior. The essential feature of the model is that a large firm's history of wages is observable to all the current and future workers, while a small firm is not visible and only its current offer is observable. Therefore a small firm is expected to be a myopic low-wage payer, and its workers search and quit often. A large firm can prevent search if it maintained a high wage throughout the past, thus making workers expect high future wages. In this way, the firm size determines the worker expectations of its future wages, which changes the quit rate and equilibrium wages. To give additional support to our theoretical result, we test a new aspect of firm size-wage effect. Since the effect on wage levels are extensively studied, we derive two main hypotheses on wage gains after job changes. (H1) The proportion of firms that are larger than the previous employer increases the wage gain. (H2) The size of the previous employer decreases the wage gain. The firm size distribution effect (H1) is a new test. We obtain supports for both. Thus we conclude that the wages are strategies and affected by how workers utilize the firm size information in changing jobs. (297 words.)

    Fluorescence and Electron Microscopic Studies of the Cytoskeletal Organi­zation of Normal, Established and Transformed Chick Embryo Cells

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    The cytoskeletons of two established chick embryo cell (CEC) lines were examined by fluorescence and electron microscopy and compared with those of control cells and cells transformed by Rous sarcoma virus (RSV). In normal CEC, many stress fibers were observed. On the other hand, stress fibers were disorganized in nontransformed spontaneously established CEC, non-tumorigenic CEC partially transformed with a chemical carcinogen, and tumorigenic RSV-transformed CEC. In the normal CEC, actin filaments formed several bundles along the processes of the cell. Stereo-images of the peripheral region revealed bundles of filaments which were located along the attached side to the substrate. A fine well preserved network of filaments was also observed. On the other hand, in spontaneously established, partially transformed and RSV-transformed CEC, a fine network of filaments, but no actin cables, was found. These results support previous evidence that the cytoskeletal changes themselves are not directly related to the transformation or tumorigenicity of cells. </p

    Voluntarily Separable Repeated Prisoner’s Dilemma.

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    Abstract: In Fujiwara-Greve and Okuno-Fujiwara (2009), an evolutionary stability concept was defined by allowing mutations of any strategy. However, in human societies, not all strategies are likely to be tried out when a player considers what happens in the future. In this paper we introduce the &quot;shared belief&quot; of potential continuation strategies, generated and passed on in a society, and mutations are restricted only among best responses against the shared belief. We show that a myopic strategy becomes a part of a bimorphic equilibrium under a shared belief and contributes to a higher payoff than ordinary neutrally stable distributions&apos;

    FACILE SYNTHESIS OF 2,3-DISUBSTITUTED PYRROLES FROM 2-SUBSTITUTED 1-PYRROLINES

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    2-Substituted-1-pyrrolines react with various arylaldehyde acetals in the presence of a Lewis acid and base to give 2-substituted 3-arylmethylidene-1-pyrrolines, which are transformed to 2,3-disubstituted pyrroles by base-catalyzed double-bond isomerization.ArticleHETEROCYCLES. 85(5):1187-1195 (2012)journal articl

    Recent Changes and Improvements in Multidisciplinary Perioperative Management From a Nutritional Perspective: Dental Specialty Should Be Considered Important

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    Purpose of review Recently, multidisciplinary strategies on accelerated recovery postoperatively have been provided, and management of the perioperative period has changed and improved dramatically. We summarize the enhanced recovery after surgery (ERAS®) protocol and its outcomes from a nutritional perspective. We established the perioperative management center (PERiO), much of whose work contents conform to ERAS®, but intensive dental staff involvement is characteristic. We also summarize its outcomes. Recent findings ERAS® is a multimodal perioperative care pathway designed to achieve early recovery for patients undergoing a major surgery. Nutrition is a key pillar for patient-care. Throughout the perioperative period, oral nutrition is suggested as well as possible. Good outcomes have been reported by a meta-analysis of randomized controlled trials. However, dental staff are not regarded as part of the professional team. PERiO reported good outcomes of care bundles and suggested the importance of dental staff contribution. The Japanese social insurance system began to cover involvements of dental staff for perioperative oral management since 2012. Analysis of the nationwide administrative claims database in Japan concluded that preoperative oral care by a dentist significantly reduced postoperative complications in patients undergoing cancer surgery. Summary Currently, dental staff are not regarded as key professionals of ERAS®, although dental staff can contribute to good outcomes in the perioperative period and PERiO, and consequently the Japanese universal health insurance coverage system covering involvements of dental staff for perioperative oral management showed good outcomes. Therefore, further clinical studies involving the dental specialty should be considered important for perioperative management from nutritional perspectives

    "Social Norms and Voluntary Cooperations"(in Japanese)

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    Unlike the ordinary repeated games, in the real world, people can run away after cheating. In this paper we construct a social game, in which players can repeat Prisoners' Dilemma only if both players agree to continue the partnership. We investigate how a social sanction prevents moral hazard in such a voluntary relationship. We have three conclusions. First, it is possible to enforce voluntary long-term cooperation by trust-building. Second, the trust-building periods can be shortened under diverse strategy distributions. Third, if there is a reference letter system which conveys information that a partnership ended by an unavoidable cause, then the trust-building periods can be shortened as well.

    Suppressive Effect of Juzentaihoto on Vascularization Induced by B16 Melanoma Cells In Vitro and In Vivo

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    Juzentaihoto (JTT) is well known to be one of Japanese herbal medicines, and used for the supplemental therapy of cancer patients with remarkable success. The present study, therefore, was undertaken to examine the possible therapeutic mechanisms of JTT on cancer using B16 melanoma cell (B16 cell)/experimental mouse system. JTT was well mixed with rodent chow at 3.0% concentrations, and was administered orally ad libitum. Administration of JTT was started one week before tumor cell injection and continued throughout the experiment. Administration of JTT into mice significantly inhibited tumor metastasis in lungs after intravenous injection of 2 × 105 B16 cells in a volume of 50 μL. JTT also significantly suppressed enlargement of tumor size in hind footpad after the subcutaneous injection of 2 × 105 (50 μL) B16 cells. In the second part of experiments, the chamber that containing B16 cells was buried in the murine back. In JTT administrated group, vascular endothelial growth factor (VEGF) of chamber internal fluid significantly decreased, and vascularization of chamber circumference was also inhibited. These results strongly suggest that oral administration of JTT caused decrease in the generation of VEGF, which is responsible for vascularization, and results in inhibition of B16 cell metastasis
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