Extremal RN/CFT in Both Hands Revisited

We study RN/CFT correspondence for four dimensional extremal Reissner-Nordstrom black hole. We uplift the 4d RN black hole to a 5d rotating black hole and make a geometric regularization of the 5d space-time. Both hands central charges are obtained correctly at the same time by Brown-Henneaux technique.Comment: 10 pages, no figur

Rationales of Mortgage Insurance Premium Structures

This paper examines the rationales for the design of mortgage insurance premium structures. The actuarially sound premium prices of several widely used structures are formally derives. Two types of cross-subsidization are identified in different structures: (1) subsidization across termination years and (2) extra-subsidization of defaulters by non-defaulters. Because these two types of subsidization exist to different degree among the structures, a borrower may self-select into certain structures to maximize (minimize) the benefits (losses) of cross-subsidies. Adverse selection arises when the borrower's characteristics cannot be completely observed by the insurer. The actuarially sound premium prices should be adjusted for such adverse selection behaviors. Numerical examples are provided to illustrate such adjustments.

Grand-canonical variational approach for the t-J model

Gutzwiller-projected BCS wave function or the resonating-valence-bond (RVB) state in the 2D extended t-J model is investigated by using the variational Monte Carlo technique. We show that the results of ground-state energy and excitation spectra calculated in the grand-canonical scheme allowing particle number to fluctuate are essentially the same as previous results obtained by fixing the number of particle in the canonical scheme if the grand thermodynamic potential is used for minimization. To account for the effect of Gutzwiller projection, a fugacity factor proposed by Laughlin and Anderson few years ago has to be inserted into the coherence factor of the BCS state. Chemical potential, particle number fluctuation, and phase fluctuation of the RVB state, difficult or even impossible to be calculated in the canonical ensemble, have been directly measured in the grand-canonical picture. We find that except for La-214 materials, the doping dependence of chemical potential is consistent with experimental findings on several cuprates. Similar to what has been reported by scanning tunneling spectroscopy experiments, the tunneling asymmetry becomes much stronger as doping decreases. We found a very large enhancement of phase fluctuation in the underdoped regime.Comment: 9 pages, 6 figure

Adaptive strategies in reef-building corals

One of the major goals of ecology is to identify metrics of assemblage structure that are easy to obtain and that enable accurate predictions of how assemblages respond to disturbance and environmental change. One recent approach, termed Universal Adaptive Strategy Theory (UAST), has been hypothesised to apply to all creatures on the tree of life. However, previous attempts to classify reef-building corals according to UAST have been inconclusive, perhaps because they have not chosen species traits according to the principles set out in the theory. In addition, the utility of the approach for predicting the response of coral assemblages to disturbance has not been effectively tested. This aims of my thesis was to test whether UAST applies to reef-building corals and whether or not adaptive strategy grouping are useful for predicting the response of taxa to disturbance. In Chapter 2, I first classify coral species into groups using the principles of UAST and a comprehensive database of coral traits. Next, in Chapter 3, I test the ability of adaptive strategy groups to predict the response of coral taxa to disturbance using a long-term dataset from inshore reefs on the Great Barrier Reef (GBR). Finally, in Chapter 4, I test for variation in the relative abundance of adaptive strategy groups in coral assemblages along the 1600 km latitudinal or environmental gradient that is the GBR. I found that UAST does not apply to corals and the analyses suggests only two groups of species rather than the three predicted by the theory. I also found that adaptive strategy groups do not accurately predict how a taxa will respond to disturbance nor do these groups respond in a predictable way along an environmental gradient. In conclusion, it is much more tractable and informative to explore traits directly, rather than looking for groups based on traits

Cyber Democracy Versus Controlling Shareholders: The Implications of E-Voting System for Corporate Governance

Based on the ideology of cyber democracy, Taiwan government has just begun to require the publicly-listed companies to implement the practice of e-voting system in stockholder meetings since 2012. One of the objectives of this mandate is to promote stockholder's activism to rectify the phenomenon of excess control associated with controlling shareholders, who dominate the boards of directors but own disproportionate ownership, to comply with the principle of one-share-one-vote. Though with good intention, the effectiveness of the e-voting system remains a question, given that it has been implemented only for a short period of time. In addition, the function of some auxiliary practices to supplement e-voting system such as director nomination also needs to be tested. This study proposes three hypotheses regarding the relationships among e-voting, board nomination, excess control, and firm performance. Using the data of 829 Taiwanese publicly-listed companies across the time period between 2012 and 2014, this study finds that the separate adoption of e-voting and board nomination increases the level of excess control and is, thus, detrimental to firm performance. On the other hand, the simultaneous adoption of the two practices can significantly decrease the level of excess control of controlling shareholders, which, in turn, contributes to firm performance. The findings bring important implications to corporate governance and policy formulation of the administration

Recrystallized parylene as a mask for silicon chemical etching

This paper presents the first use of recrystallized parylene as masking material for silicon chemical etch. Recrystallized parylene was obtained by melting parylene C at 350°C for 2 hours. The masking ability of recrystallized parylene was tested in HNA (hydrofluoric acid, nitric acid and acetic acid) solution of various ratios, KOH (potassium hydroxide) solution and TMAH (tetramethylammonium hydroxide) at different temperatures and concentrations. It is found that interface between parylene and the substrate can be attacked, which results in undercuts. Otherwise, recrystallized parylene exhibited good adhesion to silicon, complete protection of unexposed silicon and silicon etching rates comparable to literature data