Partial Observability and its Consistency for PDEs

In this paper, a quantitative measure of partial observability is defined for PDEs. The quantity is proved to be consistent if the PDE is approximated using well-posed approximation schemes. A first order approximation of an unobservability index using an empirical Gramian is introduced. Several examples are presented to illustrate the concept of partial observability, including Burgers' equation and a one-dimensional nonlinear shallow water equation.Comment: 5 figures, 25 pages. arXiv admin note: substantial text overlap with arXiv:1111.584

Reduced-order modeling using Dynamic Mode Decomposition and Least Angle Regression

Dynamic Mode Decomposition (DMD) yields a linear, approximate model of a system's dynamics that is built from data. We seek to reduce the order of this model by identifying a reduced set of modes that best fit the output. We adopt a model selection algorithm from statistics and machine learning known as Least Angle Regression (LARS). We modify LARS to be complex-valued and utilize LARS to select DMD modes. We refer to the resulting algorithm as Least Angle Regression for Dynamic Mode Decomposition (LARS4DMD). Sparsity-Promoting Dynamic Mode Decomposition (DMDSP), a popular mode-selection algorithm, serves as a benchmark for comparison. Numerical results from a Poiseuille flow test problem show that LARS4DMD yields reduced-order models that have comparable performance to DMDSP. LARS4DMD has the added benefit that the regularization weighting parameter required for DMDSP is not needed.Comment: 14 pages, 2 Figures, Submitted to AIAA Aviation Conference 201

Nanoscale Au-ZnO heterostructure developed by atomic layer deposition towards amperometric H2O2 detection

Nanoscale Au-ZnO heterostructures were fabricated on 4-in. SiO2/Si wafers by the atomic layer deposition (ALD) technique. Developed Au-ZnO heterostructures after post-deposition annealing at 250 degrees C were tested for amperometric hydrogen peroxide (H2O2) detection. The surface morphology and nanostructure of Au-ZnO heterostructures were examined by field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), etc. Additionally, the electrochemical behavior of Au-ZnO heterostructures towards H2O2 sensing under various conditions is assessed by chronoamperometry and electrochemical impedance spectroscopy (EIS). The results showed that ALD-fabricated Au-ZnO heterostructures exhibited one of the highest sensitivities of 0.53 mu A mu M(-1)cm(-2), the widest linear H2O2 detection range of 1.0 mu M-120mM, a low limit of detection (LOD) of 0.78 mu M, excellent selectivity under the normal operation conditions, and great long-term stability. Utilization of the ALD deposition method opens up a unique opportunity for the improvement of the various capabilities of the devices based on Au-ZnO heterostructures for amperometric detection of different chemicals

Will Investors Profit By Following The Stock Recommendations Published In Barrons?

Barron's is a weekly financial magazine published by Dow Jones. It’s considered America's premier financial weekly. Every week, Barron’s magazine will include a section “Research Reports,” which contains the analysts’ recommendations. Using event study methodology and market model as a benchmark, we calculate abnormal returns to ascertain the impact of the recommendations published in the Research Reports. We find that there are no statistically significant long-term abnormal returns associated with the published recommendations in Barron’s

A 2.0 Gb/s Throughput Decoder for QC-LDPC Convolutional Codes

This paper propose a decoder architecture for low-density parity-check convolutional code (LDPCCC). Specifically, the LDPCCC is derived from a quasi-cyclic (QC) LDPC block code. By making use of the quasi-cyclic structure, the proposed LDPCCC decoder adopts a dynamic message storage in the memory and uses a simple address controller. The decoder efficiently combines the memories in the pipelining processors into a large memory block so as to take advantage of the data-width of the embedded memory in a modern field-programmable gate array (FPGA). A rate-5/6 QC-LDPCCC has been implemented on an Altera Stratix FPGA. It achieves up to 2.0 Gb/s throughput with a clock frequency of 100 MHz. Moreover, the decoder displays an excellent error performance of lower than $10^{-13}$ at a bit-energy-to-noise-power-spectral-density ratio ($E_b/N_0$) of 3.55 dB.Comment: accepted to IEEE Transactions on Circuits and Systems

Efficient high order semi-implicit time discretization and local discontinuous Galerkin methods for highly nonlinear PDEs

International audienceIn this paper, we develop a high order semi-implicit time discretization method for highly nonlinear PDEs, which consist of the surface diffusion and Willmore flow of graphs, the Cahn-Hilliard equation and the Allen-Cahn/Cahn-Hilliard system. These PDEs are high order in spatial derivatives, which motivates us to develop implicit or semi-implicit time marching methods to relax the severe time step restriction for stability of explicit methods. In addition, these PDEs are also highly nonlinear, fully implicit method will incredibly increase the difficulty of implementation. In particular, we can not well separate the stiff and non-stiff components for these problems, which leads to the traditional implicit-explicit methods nearly meaningless. In this paper, a high order semi-implicit time marching method and the local discontinuous Galerkin spatial method are coupled together to achieve high order accuracy in both space and time, and to enhance the efficiency of the proposed approaches, the resulting linear or nonlinear algebraic systems are solved by multigrid solver. Numerical simulation results in one and two dimensions are presented to illustrate that the combination of the local discontinuous Galerkin method for spatial approximation, semi-implicit temporal integration with the multigrid solver provides a practical and efficient approach when solving this family of problems

Aromatic plants in East-Asia to enhance natural enemies towards biological control of insect pests. A review

Introducing flowering plants in fields may attract and benefit predators and parasitoids of insect pests and potentially enhance biological control when associated with crops. Through a vote counting analysis, the present review evaluates whether aromatic plants of East Asia could be used in this purpose. Through a systematic search of the scientific literature, we identified 64 papers published worldwide considering 32 aromatic plant species. We found a significant number of studies reporting that Apiaceae aromatic plants (Anethumgraveolens L., Coriandrumsativum L., Foeniculumvulgare L.) attract and benefit (in terms of longevity and/or fecundity) insect predators. Contrasting results were found for parasitoids, as well as with plant species from other families (mostly Asteraceae and Lamiaceae). Functional traits of plants (corolla shape, colour, volatiles) and of insects (mouthparts mainly) were considered to discuss these results. Additionally, we have not found a significant number of studies reporting an enhancement of biological control in crop or fruit trees cultivated adjacent to aromatic plants. However, the number of studies was limited, suggesting a need for further field-based research. Still, the retrieved studies highlight a recent interest for sowing aromatic plants in fields and orchards towards biological control of insect pests in East Asia and especially in China

Do Chinese Stock Markets React To The Newspaper Recommendations?

This paper studies how the stock prices in Chinese stock markets react to the stock recommendations from a Chinese business newspaper Zhong Guo Zheng Quan Bao (China Security). Using event study methodology and market model as a benchmark, we calculate abnormal returns to ascertain the impact of published recommendations. We find that there are no statistically significant long-term abnormal returns associated with the published recommendations. However, there are profitable opportunities if investors act prior to the published recommendations. We also find that the recommendations from the newspaper causes a significant short term movement two days after the publication day, suggesting a delayed response from the investors who act on the recommendation. The delayed response shows the gradual dissemination of the information in Chinese stock markets. In summary, these results indicate that press recommendations of Chinese stocks contain no useful economic information for investors who act on the published recommendations. The possible abnormal returns for investors who buy the stocks before the recommendations are made public are evidence of a market that is strong-form inefficient and the delayed response from investors to the newspaper recommendations is most likely the evidence of a market that is semi-strong-form inefficient

Economic Growth And FDI In China

This paper studies the importance of foreign direct investment (FDI) in economic development in China. By analyzing the data from China and comparing China with other developed and developing countries, the paper finds that FDI becomes a force in economic growth, especially in the later stage of industrialization; Specifically, the paper finds that a country’s foreign trade is the engine in the initial stage of the economic development, while FDI is the main force in the post-industrialization stage

Functional Characterization and Evolution of the Isotuberculosinol Operon in Mycobacterium Tuberculosis and Related Mycobacteria

Terpenoid metabolites are important to the cellular function, structural integrity, and pathogenesis of the human-specific pathogen Mycobacterium tuberculosis (Mtb). Genetic and biochemical investigations have indicated a role for the diterpenoid isotuberculosinol (isoTb) early in the infection process. There are only two genes (Rv3377c and Rv3378c) required for production of isoTb, yet these are found in what appears to be a five-gene terpenoid/isoprenoid biosynthetic operon. Of the three remaining genes (Rv3379c, Rv3382c, and Rv3383c), previous work has indicated that Rv3379c is an inactive pseudo-gene. Here we demonstrate that Rv3382c and Rv3383c encode biochemically redundant machinery for isoprenoid metabolism, encoding a functional 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (LytB) for isoprenoid precursor production and a geranylgeranyl diphosphate (GGPP) synthase, respectively, for which the Mtb genome contains other functional isozymes (Rv1110 and Rv0562, respectively). These results complete the characterization of the isoTb biosynthetic operon, as well as further elucidating isoprenoid metabolism in Mtb. In addition, we have investigated the evolutionary origin of this operon, revealing Mtb-specific conservation of the diterpene synthase genes responsible for isoTb biosynthesis, which supports our previously advanced hypothesis that isoTb acts as a human-specific pathogenic metabolite and is consistent with the human host specificity of Mtb. Intriguingly, our results revealed that many mycobacteria contain orthologs for both Rv3383c and Rv0562, suggesting a potentially important role for these functionally redundant GGPP synthases in the evolution of terpenoid/isoprenoid metabolism in the mycobacteria