Phuong Nguyen

The State is a necessary institution to maintain human existence. Besides, carrying out a research on the State always makes it tend to serve human life so that life is fairer, equal, and more charitable, which is a matter of great urgency. In Vietnam, the nature of the State is a state of the people, by the people, for the people as stipulated in the constitution. Therefore, the Vietnamese State needs to undertake the task of primarily serving the people. This requires the State to be accountable for the people for all the issues under its management. The article's new point provides a basis to prove that the socialist rule of law state is a responsible state through the analysis of the specificity, inevitability, and contents of the State's responsibility. It is also the application of state ideology to always aim for a good life and serve the common interests of Aristotle.

This thesis consists of three substantive studies about the Vietnam stock market. In particular, I study the asymmetric information, corporate governance (CG) practices, and foreign investment of publicly listed companies in Vietnam, presented in Chapters 2, 3, and 4, respectively. In Chapter 2, I investigate the effectiveness of a market surveillance system (MSS) on improving the market quality of the Vietnam stock market, as measured by liquidity and informed trading level. I find that market liquidity decreased after the introduction of the MSS, and that the effect is more pronounced for small firms. Although informed trading, on average, does not change significantly after the MSS, subsample analysis indicates a significant decrease in informed trading among large and liquid firms. In Chapter 3, I investigate the relationship between firms’ CG practices and informed trading. I find a negative relationship between the two variables. Firms with better CG practices have a lower level of informed stock trading. Moreover, a natural experiment on a shock of firms’ CG practices generated by the CG policies shows that the negative relationship between CG practices and informed trading is a causal one, in which a change in the former causes a change in the latter. In another analysis around the implementation of the MSS, I find that the implementation of the surveillance system affects the relationship between the two variables, and this effect is driven by large and liquid firms. In Chapter 4, I investigate whether foreign investors in the Vietnam stock market are informed about firms’ performance. Using the residuals of foreign investor ownership as a measure of the abnormal foreign investor holding, I find that the abnormal foreign investor holding is positively correlated with firm performance in the following one year. I also find a positive correlation between abnormal foreign investor holding and the stock returns in the next three quarters. These findings indicate that foreign investors are informed about the firms up to a one-year period.

Soil nematodes play an important role in indication for assessing soil environments and ecosystems. Previous studies of nematode community analyses based on molecular identification have shown to be useful for assessing soil environments. Here we applied PCR-DGGE method for molecular analysis of five soil nematode communities collected from four provinces in Southeastern Vietnam based on SSU gene. By sequencing DNA bands derived from S5 community sample, our data show 15 species containing soil nematode, other nematode and non-nematode species. Genus Meloidogyne was found as abundant one. The genetic relationship of soil nematode species in S5 community were determined by Maximum Likelihood tree re-construction based on SSU gene. This molecular approach is applied for the first time in Vietnam for identification of soil nematode communities.

We define a new NP search problem, the “local improvement” principle, about labellings of an acyclic, bounded-degree graph. We show that, provably in , it characterizes the consequences of and that natural restrictions of it characterize the consequences of and of the bounded arithmetic hierarchy. We also show that over V0 it characterizes the consequences of V1 and hence that, in some sense, a miniaturized version of the principle gives a new characterization of the consequences of . Throughout our search problems are “type-2” NP search problems, which take second-order objects as parameters

A number of theories have been developed to characterize ALogTime (or uniform NC 1, or just NC 1), the class of languages accepted by alternating logtime Turing machines, in the same way that Buss’s theory ${{\bf S}^{1}_{2}}$ characterizes polytime functions. Among these, ALV′ (by Clote) is particularly interesting because it is developed based on Barrington’s theorem that the word problem for the permutation group S 5 is complete for ALogTime. On the other hand, ALV (by Clote), T 0 NC 0 (by Clote and Takeuti) as well as Arai’s theory ${{\bf AID}+\Sigma_0^B{-}{\bf CA}}$ and its two-sorted version VNC 1 (by Cook and Morioka) are based on the circuit characterization of ALogTime. While the last three theories have been known to be equivalent, their relationship to ALV′ has been an open problem. Here we show that ALV′ is indeed equivalent to the other theories