G2 VP7遺伝子およびわが国での希少分離株であるG1 P[6]株の分子解析から考究したロタウイルスAの分子進化機構

長崎大学学位論文 学位記番号:博(医歯薬)甲第815号 学位授与年月日:平成27年12月2日Nagasaki University (長崎大学)課程博

Uso de variables de mercado en la predicción de dificultades financieras para las empresas que cotizan en Vietnam

This paper aims to investigate the classification power of market variables as predictors in the financial distress prediction model for listed companies in a frontier market as Vietnam securities market. Data is collected from 70 financially distressed companies that suffer a loss in 3 consecutive years and 156 non-financially distressed companies in Vietnam from 2010 to 2017. Four different models have been constructed using Logit regression and SVM analysis technique to make a prediction in 1 to 3-year ahead. The analysis results show that combining accounting ratios with market variables such as price volatility and P/E can improve the classification ability of the ex-ante model. In addition, contrary to the results of related previous researches in emerging markets, in this study, Logit models outperform SVM models. Therefore, for future research, models that apply other machine learning classifiers such as Decision Tree (DT) or Neural Network (NN) should be investigated.Este artículo tiene como objetivo investigar el poder de clasificación de las variables del mercado como factores predictivos en el modelo de predicción de dificultades financieras para las empresas que cotizan en bolsa en un mercado fronterizo como el mercado de valores de Vietnam. Los datos se recopilan de 70 compañías con dificultades financieras que sufrieron una pérdida en 3 años consecutivos y 156 empresas sin dificultades financieras en Vietnam desde 2010 a 2017. Se han construido cuatro modelos diferentes utilizando regresión Logit y la técnica de análisis de SVM para hacer una predicción en 1 a 3 años por delante. Los resultados del análisis muestran que la combinación de ratios contables con variables de mercado como la volatilidad de los precios y el P / E puede mejorar la capacidad de clasificación del modelo ex ante. Además, a diferencia de los resultados de investigaciones anteriores relacionadas en mercados emergentes, en este estudio, los modelos Logit superan a los modelos SVM. Por lo tanto, para futuras investigaciones, se deben investigar los modelos que aplican otros clasificadores de aprendizaje automático, como el Árbol de decisiones (DT) o la Red neuronal (NN)

Investigating the Effect of Matrices and Densities on the Efficiency of HPGe Gamma Spectroscopy Using MCNP

When determining radioactivities in environmental samples using low-level gamma spectroscopy, in order to raise detection limit, voluminous samples are used. It takes in account for the self-absorption (self-attenuation) of gamma rays in samples. The self-absorption effect is small or large depend on the sample shapes, matrices and densities. In this paper, we investigated the effect of some regular matrices such as water, soil, epoxy resin on the detector efficiency. Some analytical formulas for the correction of matrix and densities for soil sample was established and applied to calculate some activities from standard sample of IAEA-375

Feature selection methods and sampling techniques to financial distress prediction for Vietnamese listed companies

The research is taken to integrate the effects of variable selection approaches, as well as sampling techniques, to the performance of a model to predict the financial distress for companies whose stocks are traded on securities exchanges of Vietnam. A firm is financially distressed when its stocks are delisted as requirement from Vietnam Stock Exchange because of making a loss in 3 consecutive years or having accumulated a loss greater than the company’s equity. There are 12 models, constructed differently in feature selection methods, sampling techniques, and classifiers. The feature selection methods are factor analysis and F-score selection, while 3 sets of data samples are chosen by choice-based method with different percentages of financially distressed firms. In terms of classifying technique, logistic regression together with SVM are used in these models. Data are collected from listed firms in Vietnam from 2009 to 2017 for 1, 2 and 3 years before the announcement of their delisting requirement. The experiment’s results highlight the outperformance of the SVM model with F-score selection method in a data sample containing the highest percentage of non-financially distressed firms

Factors Influence on Promotion Mix in E-marketing: Case of Technology Services Enterprise in Vietnam

Purpose: The objective of this study is to clarify factors affecting the promotion mix in E-Marketing, with specific target audience being enterprises operating in the technology service industry in Vietnam.   Theoretical framework: Based on the promotion theory and social exchange theory, this study focuses on the factors that influence on the promotion decision in firms.   Design/Methodology/Approach: This study applies both qualitative and quantitative methods with data collected from a questionnaire survey.   Findings: There are 4 factors respectively Sales Promotion, Advertising, Public Relations and Personal Selling that affect the mixed promotion activities in E-Marketing of technology service enterprises in Vietnam.   Research, practical & social implications: This study propose solutions to improve the promotion activities in the e – marketing of firms in Vietnam.   Originality/Value: This study is one of the early studies that have focused in this field in Vietnam.Propósito: El objetivo de este estudio es aclarar los factores que afectan la combinación de promoción en E-Marketing, con un público objetivo específico que son las empresas que operan en la industria de servicios de tecnología en Vietnam. Marco teórico: Basado en la teoría de la promoción y la teoría del intercambio social, este estudio se centra en los factores que influyen en la decisión de promoción en las empresas. Diseño/metodología/enfoque: este estudio aplica métodos cualitativos y cuantitativos con datos recopilados de una encuesta de cuestionario. Hallazgos: Existen 4 factores, respectivamente, Promoción de Ventas, Publicidad, Relaciones Públicas y Ventas Personales que afectan las actividades mixtas de promoción en E-Marketing de las empresas de servicios de tecnología en Vietnam. Implicaciones de investigación, prácticas y sociales: este estudio propone soluciones para mejorar las actividades de promoción en el marketing electrónico de las empresas en Vietnam. Originalidad/valor: Este estudio es uno de los primeros que se han centrado en este campo en Vietnam.Objetivo: O objetivo deste estudo é esclarecer os fatores que afetam o mix de promoção no E-Marketing, tendo como público-alvo específico as empresas que operam no setor de serviços de tecnologia no Vietnã.. Referencial teórico: Com base na teoria da promoção e na teoria das trocas sociais, este estudo se concentra nos fatores que influenciam a decisão de promoção nas empresas.. Desenho/metodologia/abordagem: Este estudo aplica métodos qualitativos e quantitativos com dados coletados de uma pesquisa por questionário. Resultados: Existem 4 fatores, respectivamente, Promoção de Vendas, Publicidade, Relações Públicas e Vendas Pessoais que afetam as atividades de promoção mista em E-Marketing de empresas de serviços de tecnologia no Vietnã. Pesquisa, implicações práticas e sociais: Este estudo propõe soluções para melhorar as atividades de promoção no e – marketing de empresas no Vietnã. Originalidade/valor: Este estudo é um dos primeiros estudos que se concentraram neste campo no Vietnã. Palavras-chave:  Mix de promoção; E-Marketing; Serviços de tecnologia; Vietn

Molecular epidemiology of Japanese encephalitis in northern Vietnam, 1964?2011: genotype replacement

Background: Japanese encephalitis virus (JEV) is an arthropod-borne virus causing serious public health issues in Asia. JEV consists of five genotypes and recent studies have shown the emergence of JEV genotype I (GI) and its replacement of genotype III (GIII). Using an archival JEV collection, we investigated the molecular evolution of JEV in Vietnam over the last 48 years (1964-2012) in humans, mosquitoes, and pigs, within the global context. Methods: The nine JEV isolates from humans, pigs, and mosquitoes sequenced in this study and 29 sequences available in GenBank were used to analyze the envelope (E) protein of the Vietnamese JEVs. A collection of 225 cerebrospinal fluid specimens from patients with suspected Japanese encephalitis (JE) was also tested and genotyped with real-time RT-PCR. Results: The 38 E genes identified with sequencing and nine Vietnamese JEV strains genotyped with real-time RT-PCR, belonging to two lineages, evolved in accordance with those in the rest of the world. The first GIII strain was detected in humans in Vietnam in 1964, and in mosquitoes in 1979, whereas GI strains were first detected in humans and mosquitoes in 1990 and 1994, respectively. After 2004, GI was the only genotype detected in Vietnam, demonstrating that the GIIII strains had been displaced by GI strains. Five haplotypes were identified in the Vietnamese JEVs, with SKSS predominant. The S123N and S123R substitutions in the E protein were already present in the Vietnamese JEVs. Conclusion: This study describes the long evolutionary history of JEV in Vietnam over 34 years, which correlates well with the global evolution of JEV. The Vietnamese GIII strains have been replaced by GI strains in mosquitoes, pigs, and humans. The predominant haplotypes of the Vietnamese strains support this genotype displacement in Vietnam. Further surveillance is required to confirm the disappearance of the GIII strains in nature and the emergence of new pathogens causing encephalitis in Vietnam, after the long-term use of JEV vaccines in that country

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke