176 research outputs found

    Optimal Timing in Trading Japanese Equity Mutual Funds: Theory and Evidence

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    This paper provides both theoretical and empirical analyses of market participants' optimal decision-making in trading Japanese equity mutual funds. First, we build an intertemporal decision-making model under uncertainty in the presence of transaction costs. This setting enables us to shed light on the investors' option to delay investment. A comparative analysis shows that an increase in uncertainty over the expected rate of return on mutual funds has a negative impact not only on market participants' buying behavior but also on their selling behavior. In addition, a several percent increase in front-end loads and redemption fees is likely to change the optimal holding ratio of mutual funds in investors' portfolios, by up to 10 percent. Second, we empirically examine the theoretical implications using daily transaction data of selected equity mutual funds in Japan. By estimating a panel data model, we conclude that for the sample period, from August 2000 to July 2001, investment behavior has been rational in light of our theoretical model. Our results suggest that investors are likely to rationally postpone their purchases of equity mutual funds under the present circumstances of low expected returns, high degree of uncertainty, and high trading costs.

    Torsional-Lateral Coupled Vibration Of Centrifugal Compressor System At Interharmonic Frequencies Related To Control Loop Frequencies In Voltage Source Inverter.

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    Case StudyCentrifugal compressor train in a refinery experienced high vibration problem due to torsional resonance. Sidebands in the VFD output current based on VFD control loop frequencies were identified as the root cause. In this VFD, stator current was used for torque and speed control, hence control loop frequencies had a potential to generate such sidebands. Frequencies of this type of sidebands widely vary with the rotation speed (proportional to harmonics of the fundamental frequency), hence it is difficult to avoid resonance at the train torsional natural frequency. In addition, even if a compressor system is proven to have sufficient safety margin against high cycle fatigue failure due to the torque pulsation by this mechanism, such minute torque pulsation may have a potential to excite high lateral vibration at speed adjusting gear. If unpredicted or overlooked during design stage, such high vibration may disturb plant operation. This case study therefore proposes guidelines to predict such vibration levels by a simplified torsional-lateral coupled vibration analysis

    Vulvar microinvasive squamous cell carcinoma arising in vulvar intraepithelial neoplasia 3 complicated by genital warts and systemic lupus erythematosus: a case report

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    A patient suffering from long-term systemic lupus erythematosus attended with a complaint of recurrent genital warts. Perineal white-colored skin and a peri-anal papillary protrusion adjacent to the genital warts were biopsied and determined to be vulvar intraepithelial neoplasia (VIN) 3 and microinvasive squamous cell carcinoma (SCC), respectively. These lesions were locally excised. Human papillomavirus (HPV)-6 was detected in these lesions, including in the genital warts, while HPV-56 was detected only in the perineal VIN3 and peri-anal microinvasive SCC.

    Sideward Peak of Intermediate Mass Fragments in High Energy Proton Induced Reactions

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    Intermediate mass fragment (IMF) formation in the 12 GeV proton induced reaction on Au target is analyzed by using a combined framework of a transport model (JAM/MF) and a newly developed non-equilibrium percolation (NEP) model. In this model, we can well reproduce the mass distribution of fragments. In addition, the sideward peaked angular distribution would emerge under the condition that the fragment formation time is very short, around 20 fm/c. Within this short time period, the un-heated part of the residual nucleus is kept to have doughnut shape, then the Coulomb repulsion from this shape strengthens the sideward peak of IMF.Comment: 22 pages, Latex, 6 embedded PS figure

    No association between the sigma receptor type 1 gene and schizophrenia: results of analysis and meta-analysis of case-control studies

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    BACKGROUND: Several lines of evidence have supported possible roles of the sigma receptors in the etiology of schizophrenia and mechanisms of antipsychotic efficacy. An association study provided genetic evidence that the sigma receptor type 1 gene (SIGMAR1) was a possible susceptibility factor for schizophrenia, however, it was not replicated by a subsequent study. It is necessary to evaluate further the possibility that the SIGMAR1 gene is associated with susceptibility to schizophrenia. METHODS: A case-control association study between two polymorphisms of the SIGMAR1 gene, G-241T/C-240T and Gln2Pro, and schizophrenia in Japanese population, and meta-analysis including present and previous studies. RESULTS: There was no significant association of any allele or genotype of the polymorphisms with schizophrenia. Neither significant association was observed with hebephrenic or paranoid subtype of schizophrenia. Furthermore, a meta-analysis including the present and previous studies comprising 779 controls and 636 schizophrenics also revealed no significant association between the SIGMAR1 gene and schizophrenia. CONCLUSION: In view of this evidence, it is likely that the SIGMAR1 gene does not confer susceptibility to schizophrenia

    XAB2, a novel tetratricopeptide repeat protein, involved in transcription-coupled repair and transcription.

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    Nucleotide excision repair is a highly versatile DNA repair system responsible for elimination of a wide variety of lesions from the genome. It is comprised of two subpathways: transcription-coupled repair that accomplishes efficient removal of damage blocking transcription and global genome repair. Recently, the basic mechanism of global genome repair has emerged from biochemical studies. However, little is known about transcription-coupled repair in eukaryotes. Here we report the identification of a novel protein designated XAB2 (XPA-binding protein 2) that was identified by virtue of its ability to interact with XPA, a factor central to both nucleotide excision repair subpathways. The XAB2 protein of 855 amino acids consists mainly of 15 tetratricopeptide repeats. In addition to interacting with XPA, immunoprecipitation experiments demonstrated that a fraction of XAB2 is able to interact with the transcription-coupled repair-specific proteins CSA and CSB as well as RNA polymerase II. Furthermore, antibodies against XAB2 inhibited both transcription-coupled repair and transcription in vivo but not global genome repair when microinjected into living fibroblasts. These results indicate that XAB2 is a novel component involved in transcription-coupled repair and transcription

    Clinical and Functional Characterization of URAT1 Variants

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    Idiopathic renal hypouricaemia is an inherited form of hypouricaemia, associated with abnormal renal handling of uric acid. There is excessive urinary wasting of uric acid resulting in hypouricaemia. Patients may be asymptomatic, but the persistent urinary abnormalities may manifest as renal stone disease, and hypouricaemia may manifest as exercise induced acute kidney injury. Here we have identified Macedonian and British patients with hypouricaemia, who presented with a variety of renal symptoms and signs including renal stone disease, hematuria, pyelonephritis and nephrocalcinosis. We have identified heterozygous missense mutations in SLC22A12 encoding the urate transporter protein URAT1 and correlate these genetic findings with functional characterization. Urate handling was determined using uptake experiments in HEK293 cells. This data highlights the importance of the URAT1 renal urate transporter in determining serum urate concentrations and the clinical phenotypes, including nephrolithiasis, that should prompt the clinician to suspect an inherited form of renal hypouricaemia

    Molecular Mechanism of the Urate-lowering Effects of Calcium Channel Blockers

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    Hyperuricemia has recently been recognized as one of the risk factors for cardiovascular diseases. Some calcium channel blockers(CCBs), commonly used in the treatment of hypertension, have been reported to decrease serum urate level. Here, we tried to elucidate the molecular mechanism of the urate-lowering effects of CCBs. We performed [^C]urate uptake in cells stably expressing human urate transporter 1, a major contributor of renal urate reabsorption and a major target of uricosuric drugs such as benzbromarone and losartan(HEK-URAT1), together with mock(HEK-mock)cells to analyze the uricosuric action of CCBs. We also measured the activity of human xanthine oxidase(XO)to determine whether CCBs have inhibitory effects on urate production. The CCBs tested were nifedipine, nilvadipine, nitrendipine, benidipine, nisoldipine, nicardipine, efonidipine, amlodipine, azelnidipine, verapamil and diltiazem. We found for the first time that at least seven CCBs in the dihydropyridine subgroup interacted with URAT1-mediated urate uptake in HEK-URAT1 cells. Among these CCBs, nifedipine, nilvadipine and nitrendipine strongly inhibited URAT1-mediated urate uptake. Their IC_s were 15.8, 0.018 and 0.40?μM, respectively. In contrast, urate production mediated by XO was weakly inhibited by nifedipine and nisoldipine. In summary, URAT1 interacted with various CCBs differently, whereas XO, a major enzyme for urate production in the liver, did not interact with most of CCBs. Although CCBs were not excreted from the urine basically, their urate-lowering effects may be associated with the inhibition of renal urate reabsorption mediated by renal urate transporters such as URAT1 with their metabolites, and the results for structure-activity information in this study will provide a clue for developing new uricosuric drugs targeting URAT1
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