A semiparametric method for predicting bankruptcy

Bankruptcy prediction methods based on a semiparametric logit model are proposed for simple random (prospective) and case–control (choice‐based; retrospective) data. The unknown parameters and prediction probabilities in the model are estimated by the local likelihood approach, and the resulting estimators are analyzed through their asymptotic biases and variances. The semiparametric bankruptcy prediction methods using these two types of data are shown to be essentially equivalent. Thus our proposed prediction model can be directly applied to data sampled from the two important designs. One real data example and simulations confirm that our prediction method is more powerful than alternatives, in the sense of yielding smaller out‐of‐sample error rates. Copyright © 2007 John Wiley & Sons, Ltd.     

AOP event manager in open service gateway

The Open Service Gateway Initiative (OSGi) has played an important role in ubiquitous environments that support interoperability among embedded devices, such as home appliances and network devices. However, the OSGi does not have a common event mechanism yet, and it is difficult to communicate among services asynchronously. In the present work, a common event manager, Aspect-Oriented Event Manager (AOEM), was designed on an OSGi framework. AOEM supports services to generate and provide notification of events. This paper presents the implementation of AOEM as an OSGi bundle with AspectJ. The experiment on transferring between device service and application service demonstrate that AOEM provides good abstraction of the services and convenience.     

纪念爱因斯坦

1905年爱因斯坦发表了五篇文章: 3月发表了第一篇文章"光量子"(Light Quantum); 4月发表了第二篇"测量分子大小的新方法"(A New Method for Determining the Molecular Size),这篇文章是他的博士论文;     

Inhibition of neural tube closure by ionophore A23187 in chick embryos.

Ionophore A23187 inhibited closure of the chick neural tube through its effects on cytoskeletal components.     

Isothermal DNA amplification in vitro: the helicase-dependent amplification system

Since the development of polymerase chain reaction, amplification of nucleic acids has emerged as an elemental tool for molecular biology, genomics, and biotechnology. Amplification methods often use temperature cycling to exponentially amplify nucleic acids; however, isothermal amplification methods have also been developed, which do not require heating the double-stranded nucleic acid to dissociate the synthesized products from templates. Among the several methods used for isothermal DNA amplification, the helicase-dependent amplification (HDA) is discussed in this review with an emphasis on the reconstituted DNA replication system. Since DNA helicase can unwind the double-stranded DNA without the need for heating, the HDA system provides a very useful tool to amplify DNA in vitro under isothermal conditions with a simplified reaction scheme. This review describes components and detailed aspects of current HDA systems using Escherichia coli UvrD helicase and T7 bacteriophage gp4 helicase with consideration of the processivity and efficiency of DNA amplification.     

Bankruptcy prediction using a discrete‐time duration model incorporating temporal and macroeconomic dependencies

The purpose of this paper is to build an alternative method of bankruptcy prediction that accounts for some deficiencies in previous approaches that resulted in poor out‐of‐sample performances. Most of the traditional approaches suffer from restrictive presumptions and structural limitations and fail to reflect the panel properties of financial statements and/or the common macroeconomic influence. Extending the work of Shumway (2001), we present a duration model with time‐varying covariates and a baseline hazard function incorporating macroeconomic dependencies. Using the proposed model, we investigate how the hazard rates of listed companies in the Korea Stock Exchange (KSE) are affected by changes in the macroeconomic environment and by time‐varying covariate vectors that show unique financial characteristics of each company. We also investigate out‐of‐sample forecasting performances of the suggested model and demonstrate improvements produced by allowing temporal and macroeconomic dependencies. Copyright © 2008 John Wiley & Sons, Ltd.     

A simultaneous test of unit root and level change

Testing the existence of unit root and/or level change is necessary in order to understand the underlying processes of time series. In many studies carried out so far, the focus was only on a single aspect of unit root and level change, therefore limiting a full assessment of the given problems. Our study aims to find a solution to the given problems by testing the two hypotheses simultaneously. We derive the likelihood ratio test statistic based on the state space model, and their distributions are created by the simulation method. The performance of the proposed method is validated by simulated time series and also applied to two Korean macroeconomic time series to confirm its practical application. This analysis can provide a solution to determine the underlying structure of arguable time series. Copyright © 2009 John Wiley & Sons, Ltd.     

SPIN90 dephosphorylation is required for cofilin-mediated actin depolymerization in NMDA-stimulated hippocampal neurons

Actin plays a fundamental role in the regulation of spine morphology (both shrinkage and enlargement) upon synaptic activation. In particular, actin depolymerization is crucial for the spine shrinkage in NMDAR-mediated synaptic depression. Here, we define the role of SPIN90 phosphorylation/dephosphorylation in regulating actin depolymerization via modulation of cofilin activity. When neurons were treated with NMDA, SPIN90 was dephosphorylated by STEP61 (striatal-enriched protein tyrosine phosphatase) and translocated from the spines to the dendritic shafts. In addition, phosphorylated SPIN90 bound cofilin and then inhibited cofilin activity, suggesting that SPIN90 dephosphorylation is a prerequisite step for releasing cofilin so that cofilin can adequately sever actin filaments into monomeric form. We found that SPIN90 YE, a phosphomimetic mutant, remained in the spines after NMDAR activation where it bound cofilin, thereby effectively preventing actin depolymerization. This led to inhibition of the activity-dependent redistribution of cortactin and drebrin A, as well as of the morphological changes in the spines that underlie synaptic plasticity. These findings indicate that NMDA-induced SPIN90 dephosphorylation and translocation initiates cofilin-mediated actin dynamics and spine shrinkage within dendritic spines, thereby modulating synaptic activity.