摘要 :
Costly information acquisition makes it rational for investors to obtain important economic news with only limited frequency or limited accuracy. We show that this rational inattention to important news may make investors over- or...
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Costly information acquisition makes it rational for investors to obtain important economic news with only limited frequency or limited accuracy. We show that this rational inattention to important news may make investors over- or underinvest. In addition, the optimal trading strategy is "myopic" with respect to future news frequency and accuracy. We find that the optimal news frequency is nonmonotonic in news accuracy and investment horizon. Furthermore, when both news frequency and news accuracy are endogenized, an investor with a higher risk aversion or a longer investment horizon chooses less frequent but more accurate periodic news updates.
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Standard literature concludes that transaction costs only have a second-order effect on liquidity premia. We show that this conclusion depends crucially on the assumption of a constant investment opportunity set. In a regime-switc...
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Standard literature concludes that transaction costs only have a second-order effect on liquidity premia. We show that this conclusion depends crucially on the assumption of a constant investment opportunity set. In a regime-switching model in which the investment opportunity set varies over time, we explicitly characterize the optimal consumption and investment strategy. In contrast to the standard literature, we find that transaction costs can have a first-order effect on liquidity premia. However, with reasonably calibrated parameters, the presence of transaction costs still cannot fully explain the equity premium puzzle.
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We propose an integrated methodology for specifying AIN (advanced intelligent networks) and switch based features and analyzing their interactions in the AIN 0.1 framework. The specification of each individual feature is tied to t...
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We propose an integrated methodology for specifying AIN (advanced intelligent networks) and switch based features and analyzing their interactions in the AIN 0.1 framework. The specification of each individual feature is tied to the AIN call model and requires only a minimum amount of information in terms of control and data for interaction analysis. Once a feature is specified, its specification is then validated for consistency with respect to control and data. Interaction analysis is conducted for a set of features based on the sharing of call variables between the SSP and the SCP. With this approach, one can detect the following interactions involving AIN features: (1) side effects, where a call variable modified by one feature is used by another feature and (2) disabling, where one feature disconnects a call, preventing another feature from execution. We also develop a theory that is based on the computation of sequences of messages exchanged between the SSP and the SCP and their call variable usage. This theory is shown to dramatically reduce the number of cases considered during the analysis. A brief overview of a tool that makes use of this methodology to aid in the task of feature interaction detection is also given.
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The destruction of Fermi-liquid behavior when a gapless Fermi surface is coupled to a fluctuating gapless boson field is studied theoretically. This problem arises in a number of different contexts in quantum many-body physics. Ex...
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The destruction of Fermi-liquid behavior when a gapless Fermi surface is coupled to a fluctuating gapless boson field is studied theoretically. This problem arises in a number of different contexts in quantum many-body physics. Examples include fermions coupled to a fluctuating transverse gauge field pertinent to quantum spin-liquid Mott insulators, and quantum critical metals near a Pomeranchuk transition. We develop a controlled theoretical approach to determine the low-energy physics. Our approach relies on combining an expansion in the inverse number (N) of fermion species with a further expansion in the parameter ε=z_b-2, where z_b is the dynamical critical exponent of the boson field. We show how this limit allows a systematic calculation of the universal low-energy physics of these problems. The method is illustrated by studying spinon Fermi-surface spin liquids, and a quantum critical metal at a second-order electronic nematic phase transition. We calculate the low-energy single-particle spectra, and various interesting two-particle correlation functions. In some cases, deviations from the popular random-phase approximation results are found. Some of the same universal singularities are also calculated to leading nonvanishing order using a perturbative renormalization-group calculation at small N extending previous results of Nayak and Wilczek. Implications for quantum spin liquids and for Pomeranchuk transitions are discussed. For quantum critical metals at a nematic transition, we show that the tunneling density of states has a power-law suppression at low energies.
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The controlling factors on molecular weight distribution in emulsion polymerization are investigated using dissipative particle dynamics simulations. The propagation and bi-radical termination kinetic steps are taken into account ...
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The controlling factors on molecular weight distribution in emulsion polymerization are investigated using dissipative particle dynamics simulations. The propagation and bi-radical termination kinetic steps are taken into account in the simulations by coupling a Monte Carlo type reaction model. We find that monomer concentration can be very efficient on controlling molecular weight distribution and plays a decisive role on the formation of high molecular weight polymers. Increasing initiator concentration can effectively reduce the polymer molecular weight while increasing the polydispersity index. Moreover, increasing polymerization rate can slightly narrow the molecular weight distribution. We also find that, by suitably tuning the surfactant chain length, it may be possible to obtain an optimal molecular weight distribution in emulsion polymerization.
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A series of triaminotriazine derivatives (compounds 5a-f, 6a-x, and 7a-g) was designed, synthesized, and evaluated for their inhibition activities to colorectal cancer (CRC) cell lines (HCT-116 and HT-29). Most of the synthesized ...
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A series of triaminotriazine derivatives (compounds 5a-f, 6a-x, and 7a-g) was designed, synthesized, and evaluated for their inhibition activities to colorectal cancer (CRC) cell lines (HCT-116 and HT-29). Most of the synthesized compounds demonstrated moderate anti-proliferatory effects on both HCT-116 and HT-29 cell lines at the concentration of 10 μM. The inhibitory activities against HCT-116 and HT-29 cell lines were discussed to develop the structure-activity relationships of this new series. Compounds 61 and 6o exhibited prominent inhibition activities toward HCT-116, with IC_(50)s of 0.76 and 0.92 μM, respectively. The in vivo antitumor studies and pharmacokinetics of compound 61 showed that it might be a promising new hit for further development of antitumor agents.
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The reduced mechanisms driven from detailed mechanisms for fuel are
essential to combustion simulation. The directed relation graph with error
propagation (DRGEP) method for mechanism reduction determines the
active species bas...
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The reduced mechanisms driven from detailed mechanisms for fuel are
essential to combustion simulation. The directed relation graph with error
propagation (DRGEP) method for mechanism reduction determines the
active species based on the static target species. Inspired by the better
performance of automatic target species selection method (ATSS) in dynamic
adaptive chemistry simulation and the effectiveness of global sensitivity
analysis (GSA) in assessing the importance of elementary reaction, the
present work proposes a new reduction procedure. This procedure utilizes the
ATSS method, which has not been applied to obtaining the overall reduced
mechanism. Total 5610 status points are sampled densely during the ignition
process to obtain resulting local reduced mechanisms in present work. The
overall active species are selected according to the total occurrence
probability. The primary active reactions determined by the active species are
further eliminated using the GSA method. By comparing the auto-ignition
delay times (AIDT) of reduced methane mechanisms obtained by DRGEP
and new reduction procedures under typical initial conditions. The simulation
results prove the superiority of the combination of ATSS and GSA methods.
The ATSS method can avoid improper selection of active species compared
with traditional DRGEP method.
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A series of novel benzamide derivatives was designed, synthesized, and their inhibitory activities against glycogen phosphorylase (GP) in the direction of glycogen synthesis by the release of phosphate from glucose-1-phosphate wer...
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A series of novel benzamide derivatives was designed, synthesized, and their inhibitory activities against glycogen phosphorylase (GP) in the direction of glycogen synthesis by the release of phosphate from glucose-1-phosphate were evaluated. The structure-activity relationships (SAR) of these compounds are also presented. Within this series of compounds, 4m is the most potent GPa inhibitor (IC_(50) = 2.68 μM), which is nearly 100 times more potent than the initial compound 1. Analysis of mapping between pharmacophores of different binding sites and each compound demonstrated that these benzamide derivatives bind at the dimer interface of the rabbit muscle enzyme, and possible docking modes of compound 4m were explored by molecular docking simulation.
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Some large field digital radiography systems are cur- rently under development using multiple detectors. These small size two dimension detectors are abutted together to cover a large field. Physical gaps existing between adjacent...
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Some large field digital radiography systems are cur- rently under development using multiple detectors. These small size two dimension detectors are abutted together to cover a large field. Physical gaps existing between adjacent detectors produce seams Between the resultant subimages. In this paper, an adaptive linear Interpolation algorithm was introduced for estimating missing infor- Mation at the seams and was compared with conventional linear Interpolation and with nonlinear interpolation.
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An integrated computer-aided detection (CAD) scheme was developed for detecting and classifying metaphase chromosomes. The CAD scheme's performance and robustness is assessed. This scheme includes an automatic metaphase-finding mo...
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An integrated computer-aided detection (CAD) scheme was developed for detecting and classifying metaphase chromosomes. The CAD scheme's performance and robustness is assessed. This scheme includes an automatic metaphase-finding module and a karyotyping module, and it was applied to a testing database with 200 digital microscopic images. The automatic metaphase-finding module detects analyzable metaphase cells using a feature-based artificial neural network (ANN). The ANN-generated outputs are analyzed by a receiver operating characteristics (ROC) method, and the area under the ROC curve is 0.966. Then, the automatic karyotyping module classifies individual chromosomes of this cell into 24 types. In this module, a two-layer decision tree-based classifier with eight ANNs established in its connection nodes was optimized by a genetic algorithm. Chromosomes are first classified into seven groups by the ANN in the first layer. The chromosomes in these groups are then separately classified by seven ANNs into 24 types in the second layer. The classification accuracy is 94.5% in the first layer. Six ANNs achieved the accuracy above 95% and only one had lessened performance (80.6%) in the second layer. The overall classification accuracy is 91.5% as compared with 86.7% in the previous study using two independent datasets randomly acquired from our genetic laboratory. The results demonstrate that this automated scheme achieves high and robust performance in identification and classification of metaphase chromosomes.
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