Caractéristiques des marées dans le golfe du Tonkin

Le golfe du Tonkin, située dans la mer de l'Est/la mer de Chine du Sud, est une zone de fort intérêt écologique, touristique et économique. Améliorer notre connaissance de ses processus hydro-sédimentaires (transport de particules en suspension) est d'une grande importance. L'objectif scientifique de cette étude est de revoir les processus physiques dominants qui caractérisent la dynamique des marées dans le golfe du Tonkin en utilisant un modèle à haute résolution et la combinaison de toutes les données disponibles. Une attention particulière est donc accordée à un examen croisé du modèle, des marégraphes et de l'altimétrie en zone côtière, ainsi qu'à l'étalonnage du modèle dérivé d'un ensemble d'expériences de sensibilité aux paramètres. Le bilan d'énergie des marées du golfe (flux d'énergie et de dissipation) est ensuite analysé et ses propriétés de résonance sont évaluées et comparées avec des modèles idéalisés et les observations. Ensuite, la marée résiduelle eulérienne et lagrangienne est évaluée. Enfin, on montre que le mélange de marée ne suffit pas à expliquer les structures frontales observées et associées à des concentrations élevées de chlorophylle.The Gulf of Tonkin, situated in the Vietnam East Sea/South China Sea, is a zone of strong ecological, touristic and economic interest. Improving our knowledge of its hydro-sedimentary processes (transport of suspended particles) is of great importance. The scientific objective of this study is to revisit the dominant physical processes that characterize tidal dynamics in the Gulf of Tonkin using a high-resolution model and the combination of all available data. Particular attention is thus given to model-data cross-examination using tidal gauges and coastal satellite altimetry data and to model calibration derived from a set of sensitivity experiments to model parameters. The tidal energy budget of the gulf (energy flux and dissipation) is then analyzed and its resonance properties are evaluated and compared with idealized models and observations. Then, the tidal residual flow in both Eulerian and Lagrangian frameworks is evaluated. Finally, the problem of tidal frontogenesis is addressed showing that tidal mixing alone does not explain the observed summer frontal structures in chlorophyll concentrations

A comparison between English demonstratives and Vietnamese demonstratives in argumentative essays

In English and Vietnamese, demonstratives are considered one of the most important linguistic items for their ability to enhance writing coherence. Crucial as they are, few investigations have been conducted to analyze the differences in their uses in English and Vietnamese written discourse. This research attempts to investigate the differences in the use of Vietnamese demonstratives and English demonstratives in model Vietnamese (MV) and model American English (MA) argumentative essays. Adopting both quantitative and qualitative analyses, it focuses on the frequency and pragmatic uses of proximal and distal demonstratives in the two languages. It was discovered that English essays had significantly more proximal and cataphoric uses of demonstratives than Vietnamese essays. While English proximal demonstratives this(these) indicated topic shifting and distal demonstratives that(those) signaled topic continuity, a contrary pattern was observed in Vietnamese. Moreover, in investigating the referential uses of demonstratives, it was revealed that the use of Vietnamese demonstratives differed from English in the sense that they could act as discourse connectives facilitating the interpretation process of the readers. The study’s results contribute to the cross-language analysis and comparison of demonstratives and provide implications for the teaching of English demonstratives in academic writing in Vietnam

Earnings management: detection, application and contagion

The accounting scandals in the 2000s and 2010s have led to a number of large-scale reforms in financial reporting and corporate governance regulations around the world, and still attract a lot of public debates recently. In that context, the demand for further knowledge on earnings management is very topical. What we have known is earnings management does exist. What we have not known, however, seems still overwhelming. We need to know more about issues such as how earnings management could be detected, to what extent earnings management has an impact on investment decisions, what drives earnings management behaviour etc. The accounting research community has responded to such demand by producing a very large, and still growing, volume of publications on the topic during the last few decades. In fact, earnings management has now been one of the largest strands in the mainstream accounting literature. This thesis aims to make original and important contributions to the literature on earnings management. The main components of the thesis comprise of three empirical chapters which analyse secondary data on the United Kingdom's (the UK hereafter) stock market during the period from 1995 to 2011. The contributions are made on three important and inter-related research strands within the earnings management literature, namely the earnings management detection models, the impact of earnings management on stock market investment, and the spread of earnings management as a corporate decision through board network. The first empirical chapter constructs a signal-based composite index, namely ESCORE, which captures the context of earnings management. Specifically, ESCORE aggregates fifteen individual signals related to earnings management based on prior relevant literature. Empirical results using UK data shows that when ESCORE is higher, firms do manage earnings with greater magnitude and are more likely to be most aggressive using both accruals and real earnings management. Firms which are investigated for financial-statement-related irregularities are also shown to have significantly higher ESCORE. The composite score can be easily applied in practice as well as replicated in subsequent studies, especially in emerging market where small samples technically constrain the use of other existing earnings management detection models. The approach to construct ESCORE is innovative and it only measures the likelihood rather than the magnitude of earnings management. This aspect of ESCORE is important given the growing criticisms that none of the existing earnings management models could actually measure the magnitude of earnings management. Using ESCORE as a measure that captures the general context of earnings management, the second empirical chapter asks if investors rationally price the information contained in such context. Empirical evidence shows that firms with low ESCORE outperform those with high ESCORE by 1.37% per month after controlling for risk loadings on the market, size, book-to-market and momentum factors in up to one year after portfolio formation. The relationship between ESCORE and future returns is still significant, in both economic and statistical terms, after controlling for various other known 'market anomalies', including the size, value-glamour, seasoned equity offer, market irrational reaction to financial distress, balance sheet bloat, profitability and discretionary accruals. This finding is in line with the behavioural explanation that investors tend to ignore the observable context of earnings management under the influence of the well-documented base rate fallacy. This is an original piece of knowledge which makes significant and interesting contributions to the literature on market anomalies. The third and last empirical chapter investigates whether aggressive earnings management practices spread across firms sharing interlocked directors. The evidence shows that if a firm aggressively manages earnings (referred to as a 'contagious firm') via accruals (or production activities and discretionary expenses) manipulation in a year, any firms (referred to as 'exposed firms') which are interlocked with that contagious firm in that year and the two following years are more likely to aggressively manage earnings via accruals (or production activities and discretionary expenses, respectively) manipulation. The contagion effect is found to be more pronounced if the interlocked director is male, older, British, and charged with duties which could influence financial reporting. The contagion effect is robust after controlling for endogeneity issues and common characteristics of the interlocked firms. The evidence presented in this chapter is both original and a significant contribution to our knowledge on the impact of board networks on corporate decisions, a topic which attracts a lot of attention as it fits directly to the process of reforming corporate governance codes to enhance the efficiency and effectiveness of the boards of directors

Factors Affecting the Success of PPP Transport Projects in Vietnam

Transport infrastructure plays an important role in the development of each country, especially for developing countries like Vietnam. To promote the development of transport infrastructure as well as to deal with some challenges such as budget and project efficiency, the Public Private Partnership (PPP) model is a very proper choice. The factors that determine the success of PPP transport projects are important issues to be analyzed in different countries. The article aims at identifying the factors and the extent of their influence on the success of PPP transport project in Vietnam. Research data are collected from surveys with questionnaire to capture related partners' perceptions of success factors. The influence level of the factors is assessed on a 5-point Likert scale (from 1 - very low to 5 - very high). A total of 92 questionnaires were collected and analyzed using Statistical Package for the Social Sciences (SPSS) software to rank the influence of success factors. Research results show that “Adequate and transparent legal framework”, “State and private commitments and responsibilities”, “Transparency in bidding”, “State support policy” and “Good governance” are the top five factors determining the success of a PPP transport project in Vietnam. The new findings of the study help the State and investors better understand the factors determining the success of PPP transport projects in Vietnam in order to make appropriate decisions on policies

Poverty Targeting and Impact of a Governmental Micro-credit Program in Vietnam

It is argued that without collateral the poor often face binding borrowing constraints in the formal credit market. This justifies a micro-credit program, which is operated by the Vietnam Bank for Social Policies to provide the poor with preferential credit. This paper examines poverty targeting and impact of the micro-credit program. It is found that the program is not very pro-poor in terms of targeting. Among the participants, the non-poor account for a larger proportion of loans. The non-poor also tend to receive larger amounts of credit compared to the poor. However, the program has positive impact on poverty reduction of the participants. This positive impact is found for all the three Foster-Greer-Thorbecke poverty measures.Micro-credit, poverty, poverty targeting, impact evaluation, instrumental variables, fixed-effect model

CELLULOSE NANOCRYSTALS: SYNTHESIS, CHARACTERISTICS AND EFFECT ON HYDROXYPROPYL METHYLCELLULOSE-BASED COMPOSITE FILMS AND COATINGS

This study aimed to synthesize, determine characteristics of cellulose nanocrystals such as morphology, size particle, zeta potential, Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The study also evaluated effect of concentration of added cellulose nanocrystals to hydroxypropyl methylcellulose-base films and coatings containing carnauba Nano emulsion and chitosan nanoparticles. Results showed the shape and size of the nanoparticle generally depend on hydrolysis condition of microcrystalline cellulose. Cellulose nanocrystals obtained from processing hydrolyzed microcrystalline cellulose in range from 47 wt. % to 55 wt. % had length range of from 160 to 196 nm and diameter from 9 to 11 nm. Cellulose nanocrystals were added into nanocomposite HPMC that incorporated with both of carnauba Nano emulsion and chitosan nanoparticles with concentration of cellulose nanocrystals at levels: 0.2, 0.5, 0.8 and 1.1 %. Scanning electron microscopy (SEM) images revealed that nanocomposite films become more compact and dense due to the cellulose nanocrystals occupy empty spaces of porous of matrix nanocomposite HPMC increasing the collapse of the pores in the films. The concentration of cellulose nanocrystals at 0.5 % was added to Nanocomposite HPMC including both of carnauba nano emulsion and chitosan nanoparticles improved the physical strength of film with the best quality compared with other films as: film solubility was raised up 16.65 %, film drying time is faster than others (51.33 minutes). Assessement of the effect of cellulose nanocrystals added into the nanocomposite films coated on fruit bananas showed that respiration of bananas were reduced from 57.08 ml CO2/kg.h to 30.17 ml CO2/kg.h;  weight loss was declined from 4.0 % to 1.82 % thanks to the limitation of the films gas and moisture permeability

Disturbance observer-based controller for inverted pendulum with uncertainties: Linear matrix inequality approach

A new approach based on linear matrix inequality (LMI) technique for stabilizing the inverted pendulum is developed in this article. The unknown states are estimated as well as the system is stabilized simultaneously by employing the observer-based controller. In addition, the impacts of the uncertainties are taken into consideration in this paper. Unlike the previous studies, the uncertainties in this study are unnecessary to satisfy the bounded constraints. These uncertainties will be converted into the unknown input disturbances, and then a disturbance observer-based controller will be synthesized to estimate the information of the unknown states, eliminate completely the effects of the uncertainties, and stabilize inverted pendulum system. With the support of lyapunov methodology, the conditions for constructing the observer and controller under the framework of linear matrix inequalities (LMIs) are derived in main theorems. Finally, the simulations for system with and without uncertainties are exhibited to show the merit and effectiveness of the proposed methods

The Impacts of the COVID-19 Pandemic on First-generation, Low-income and Rural Students in Indonesia and Vietnam: A cross-cultural comparative study

The COVID-19 pandemic has had a significant impact worldwide, affecting 600 million students in higher education institutions across 200 countries. However, comparative studies by country on this topic are limited. In this paper, we explore the question: how has the COVID-19 pandemic affected higher education students and which ones have been impacted the most? Indonesia and Vietnam are our focus. We leveraged a rich set of data collected online from college/university students from both countries involving over 2600 participants, and used regression analyses to measure the students\u27 outcomes, including the dimensions of their wellbeing, financial hardships, access to technology, and educational satisfaction. As expected, we find that there are statistically significant differences between both countries, especially among first-generation, low-income and rural students in almost all the outcomes in our four domains. We observed that low-income students and rural students in both countries were less likely to have access to technology during the pandemic than their more affluent and urban counterparts. They also were more likely to endure financial hardships during the pandemic. We did not find any statistically significant estimates for students’ burnout measures among the students in these two countries. In addition, we observed lower likelihood of satisfaction from rural and low-income students in Indonesia. We provide our policy recommendations for both countries

Kinetics of Viremia and NS1 Antigenemia Are Shaped by Immune Status and Virus Serotype in Adults with Dengue

Dengue is an acute viral disease that affects tens of millions of people annually in tropical and sub-tropical countries. In some cases, this infection happens to be severe and even life threatening. Severe cases have been associated with higher levels of virus in the blood. Several hypotheses have been proposed to explain the occurrence of these cases notably by involving the patient's history of previous DEN virus infection(s). Little is known about the relationships between the evolution over time of virus levels in the blood, the clinical outcome and the previous infection(s) history—a better understanding of these features could help in anti-viral drug development. To analyze these relationships, we studied well characterized patients who participated in a clinical trial. The majority of these patients were infected by DENV-1 serotype and had higher levels of virus than those infected by DENV-2 and sometimes DENV-3 serotypes. We also found that patients with more severe symptoms had higher levels of virus in the first days of their illness. We found as well that the virus was cleared faster and earlier from the blood of patients previously infected. These findings are of major importance for further anti-viral drug testing