The late Mesozoic-Cenozoic tectonic evolution of the South China Sea: A petrologic perspective

This paper presents a review of available petrological, geochonological and geochemical data for late Mesozoic to Recent igneous rocks in the South China Sea (SCS) and adjacent regions and a discussion of their petrogeneses and tectonic implications. The integration of these data with available geophysical and other geologic information led to the following tectono-magmatic model for the evolution of the SCS region. The geochemical characteristics of late Mesozoic granitic rocks in the Pearl River Mouth Basin (PRMB), micro-blocks in the SCS, the offshore continental shelf and Dalat zone in southern Vietnam, and the Schwaner Mountains in West Kalimantan, Borneo indicate that these are mainly I-type granites plus a small amount of S-type granites in the PRMB. These granitoids were formed in a continental arc tectonic setting, consistent with the ideas proposed by Holloway (1982) and Taylor and Hayes (1980, 1983), that there existed an Andean-type volcanic arc during later Mesozoic era in the SCS region. The geochonological and geochemical characteristics of the volcanics indicate an early period of bimodal volcanism (60-43. Ma or 32. Ma) at the northern margin of the SCS, followed by a period of relatively passive style volcanism during Cenozoic seafloor spreading (37 or 30-16. Ma) within the SCS, and post-spreading volcanism (tholeiitic series at 17-8. Ma, followed by alkali series from 8. Ma to present) in the entire SCS region. The geodynamic setting of the earlier volcanics was an extensional regime, which resulted from the collision between India and Eurasian plates since the earliest Cenozoic, and that of the post-spreading volcanics may be related to mantle plume magmatism in Hainan Island. In addition, the nascent Hainan plume may have played a significant role in the extension along the northern margin and seafloor spreading in the SCS. © 2014 Elsevier Ltd

Geochemistry and petrogenesis of volcanic rocks from Daimao Seamount (South China Sea) and their tectonic implications

The South China Sea (SCS) experienced three episodes of seafloor spreading and left three fossil spreading centers presently located at 18°N, 17°N and 15.5°N. Spreading ceased at these three locations during magnetic anomaly 10, 8, and 5c, respectively. Daimao Seamount (16.6. Ma) was formed 10. my after the cessation of the 17°N spreading center. Volcaniclastic rocks and shallow-water carbonate facies near the summit of Daimao Seamount provide key information on the seamount's geologic history. New major and trace element and Sr-Nd-Pb isotopic compositions of basaltic breccia clasts in the volcaniclastics suggest that Daimao and other SCS seamounts have typical ocean island basalt-like composition and possess a 'Dupal' isotopic signature. Our new analyses, combined with available data, indicate that the basaltic foundation of Daimao Seamount was formed through subaqueous explosive volcanic eruptions at 16.6. Ma. The seamount subsided rapidly (>. 0.12. mm/y) at first, allowing the deposition of shallow-water, coral-bearing carbonates around its summit and, then, at a slower rate (<. 0.12. mm/y). We propose that the parental magmas of SCS seamount lavas originated from the Hainan mantle plume. In contrast, lavas from contemporaneous seamounts in other marginal basins in the western Pacific are subduction-related

Implicit-explicit schemes for incompressible flow problems with variable viscosity

In this work we study different Implicit-Explicit (IMEX) schemes for incompressible flow problems with variable viscosity. Unlike most previous work on IMEX schemes, which focuses on the convective part, we here focus on treating parts of the diffusive term explicitly to reduce the coupling between the velocity components. We present different, both monolithic and fractional-step, IMEX alternatives for the variable-viscosity Navier--Stokes system, analysing their theoretical and algorithmic properties. Stability results are proven for all the methods presented, with all these results being unconditional, except for one of the discretisations using a fractional-step scheme, where a CFL condition (in terms of the problem data) is required for showing stability. Our analysis is supported by a series of numerical experiments

A Study of Subic Bay Maritime Traffic Condition and Risk Analysis

This study focused on the maritime traffic condition at the Subic Bay Metropolitan Authority, Philippines. It is based on a one-year survey conducted in 24-hour monitoring of shipping traffic movements. Every month, the set is rigged in proximity to the Bay where the movements of ships are targeted. The data collected by the equipment are the ship’s tracks, the time of passage; the sizes and types of ships captured according to their LOA (length overall). These surveys were carried out in a one-day duration, each month, for a period of one (1) year to realize the pattern of movements of each ship captured around the Bay. The one-year survey conducted had shown that vessels continue to visit the Bay in various conducts of commerce. The tracks showed that the existing wharves and piers can handle medium-sized ships at present. The tracks, likewise, demonstrated that the entry/exit of vessels was scattered implying a random route chosen by vessels on a single area of the Bay. Based on the analysis of traffic conditions, it was identified that the bay lacks a traffic management system, like monitoring of movements of sea-crafts while plying in the bay, especially in the Subic Bay Metropolitan Authority area. It is then recommended to continue improving the infrastructure, systems, and redevelopment of the Bay, and to conduct a follow-up/continuum study to analyze the overall safety conditions of the Bay including the off- Subic Bay Metropolitan Authority area.&nbsp

Supramolecular gating of guest release from cucurbit[7]uril using de novo design

Herein we computationally explore the modulation of the release kinetics of an encapsulated guest molecule from the cucurbit[7]uril (CB7) cavity by ligands binding to the host portal. We uncovered a correlation between the ligand-binding affinity with CB7 and the guest residence time, allowing us to rapidly predict the release kinetics through straightforward energy minimization calculations. These high-throughput predictions in turn enable a Monte-Carlo Tree Search (MCTS) to de novo design a series of cap-shaped ligand molecules with large binding affinities and boosting guest residence times by up to 7 orders of magnitude. Notably, halogenated aromatic compounds emerge as top-ranking ligands. Detailed modeling suggests the presence of halogen-bonding between the ligands and the CB7 portal. Meanwhile, the binding of top-ranked ligands is supported by 1H NMR and 2D DOSY-NMR. Our findings open up possibilities in gating of molecular transport through a nanoscale cavity with potential applications in nanopore technology and controlled drug release

Abstract composition rule for relativistic kinetic energy in the thermodynamical limit

We demonstrate by simple mathematical considerations that a power-law tailed distribution in the kinetic energy of relativistic particles can be a limiting distribution seen in relativistic heavy ion experiments. We prove that the infinite repetition of an arbitrary composition rule on an infinitesimal amount leads to a rule with a formal logarithm. As a consequence the stationary distribution of energy in the thermodynamical limit follows the composed function of the Boltzmann-Gibbs exponential with this formal logarithm. In particular, interactions described as solely functions of the relative four-momentum squared lead to kinetic energy distributions of the Tsallis-Pareto (cut power-law) form in the high energy limit.Comment: Submitted to Europhysics Letters. LaTeX, 3 eps figure

Portfolio Selection Using Data Envelopment Analysis

There has been a growing interest in applying data envelopment analysis (DEA) as a non-parametric approach in portfolio optimization due to its flexibility in overcoming the limitations of the conventional mean-variance portfolio (MVP) model. Therefore, this study highlights the use of DEA as a portfolio selection tool that may encourage individuals to invest in the Philippine stock market for its ability to integrate any technical and fundamental factors. This study shows that the DEA model outperforms the MVP model in terms of risk-adjusted returns. However, the investor may need to change the model used to generate the highest returns because the investor may either hold a short-term or long-term investment. This study recommends that the investor does the following: (a) formulate short-term portfolios using the DEA model as it outperforms the MVP in the short-run and can provide for a versatile set of inputs and outputs that determine the optimal portfolio, and (b) formulate long-term portfolios using the MVP model as returns are mean-reverting in the long-run

A Data Envelopment Analysis Approach to Portfolio Selection: An Application to the Blue Chip Stocks in the Philippine Stock Exchange (2010-2019)

There has been a growing interest in the application of data envelopment analysis (DEA) as a nonparametric approach in portfolio optimization due to its flexibility in overcoming the limitations of the conventional mean-variance portfolio (MVP) model. Therefore, this study aims to validate the allocative efficiency of the DEA cross-efficiency model using blue chip stocks in the Philippine Stock Exchange from 2010 to 2019. This study finds that the proposed model is able to distinguish a unique set of best-performing stocks across each holding period and outperforms the MVP more consistently. The results of this study suggest that the proposed DEA cross-efficiency model can encourage more Filipinos to invest because it can provide an allocatively-efficient manner of selecting optimal stocks and incorporate other factors that affect the return and risk of a portfolio. Finally, this study suggests that future studies can examine this model using the entire Philippine stock market with an alternative set of criteria that affect stock returns and, ultimately, the stock’s performance

Thermodynamic Geometry of black hole in the deformed Horava-Lifshitz gravity

We investigate the thermodynamic geometry and phase transition of Kehagias-Sfetsos black hole in the deformed Horava-Lifshitz gravity with coupling constant $\lambda=1$. The phase transition in black hole thermodynamics is thought to be associated with the divergence of the capacities. And the structures of these divergent points are studied. We also find that the thermodynamic curvature produced by the Ruppeiner metric is positive definite for all $r_+ > r_-$ and is divergence at $\eta_2=0$ corresponded to the divergent points of $C_{\Phi}$ and $C_T$. These results suggest that the microstructure of the black hole has an effective repulsive interaction, which is very similar to the ideal gas of fermions. These may shine some light on the microstructure of the black hole.Comment: 5 pages, 3 figure