Simple Synthesis of Versatile Coumarin Scaffolds

We describe an approach using ring‐closing metathesis (RCM) to synthesize versatile coumarin derivatives that present appropriate substitutions both at the aromatic and at the α,β‐unsaturated lactone ring. The obtained compounds can be used as molecular scaffolds suitable for further diversifications through a combinatorial approach.     

A practical and efficient synthesis of 6-carboalkoxy-13-cycloalkyl-5H-indolo[2,1-a][2]benzazepine-10-carboxylic acid derivatives

A convenient and practical synthesis of 6-carboalkoxy-13-cycloalkyl-5H-indolo[2,1-a][2]benzazepine-10-carboxylic acid derivatives (6) has been developed. The key step in the synthesis utilizes an intramolecular tandem reaction sequence of a Michael addition followed by a Horner–Wadsworth–Emmons (HWE) olefination reaction between hemi-aminal 11 and methyl 2-(dimethoxyphosphoryl)acrylate 12. The ring construction occurred efficiently and purification of the products 6 was straightforward. The C-10 methyl ester of 6a was hydrolyzed selectively to the carboxylic acid 13 while the olefin of 6d was converted to the cyclopropane 14 using trimethylsulfoxonium iodide in DMSO in the presence of NaH.     

On feedback and stable price adjustment mechanisms

Given an excess demand function of an economy, say Z(p)$Z(p)$, a stable price adjustment mechanism (SPAM) guarantees convergence of solution path p(t,_p0)$p(t,p_0)$ to an equilibrium _peq$p_{\mathit{eq}}$ solution of Z(p)=0$Z(p)=0$. Besides, all equilibrium points of Z(p)$Z(p)$ are asymptotically stable. Some SPAMs have been proposed, including Newton and transpose Jacobian methods. Despite this powerful stability property of SPAMs, their acceptation in the economics community has been limited by a lack of interpretation. This paper focuses on this issue. Specifically, feedback control theory is used to link SPAMs and price dynamics models with control inputs, which match the economically intuitive Walrasian Hypothesis (i.e., prices change with excess demand sign). Under mild conditions, it is shown the existence of a feedback function that transforms the price dynamics into a desired SPAM. Hence, a SPAM is interpreted as a fundamental (e.g., Walrasian) price dynamics under the action of a feedback function aimed to stabilize the equilibrium set of the excess demand function.     

A Close-to-Aromatize Approach for the Late-Stage Functionalization through Ring Closing Metathesis

An efficient approach for the synthesis of monosubstituted aromatic compounds relying on a ring-closing metathesis followed by spontaneous 1,2-elimination is presented. The efficiency for late-stage functionalization is highlighted in various solvents (up to 920 TON). This approach is compatible with strained cycles and other multiple bonds in the substrate.     

Real-World Forward Rate Dynamics With Affine Realizations

We investigate the existence of affine realizations for Lévy driven interest rate term structure models under the real-world probability measure, which so far has only been studied under an assumed risk-neutral probability measure. For models driven by Wiener processes, all results obtained under the risk-neutral approach concerning the existence of affine realizations are transferred to the general case. A similar result holds true for models driven by compound Poisson processes with finite jump size distributions. However, in the presence of jumps with infinite activity we obtain severe restrictions on the structure of the market price of risk; typically, it must even be constant.     

An empirical re-examination of natural resource scarcity and economic growth

This paper is concerned with the effect of natural resource scarcity on economic growth in the United States. After defining the notion of scarcity and introducing two measures of scarcity—unit costs and relative resource price—changes in resource scarcity trends for lead, zinc, nickel, aluminium, silver, iron and copper over the most recent three decades are investigated. Only for silver and iron is there any indication that such a change has occurred. For silver, the change is transitory. To the extent that change takes place, it has implications for future economic growth, i.e. natural resource scarcity and economic growth are interrelated. To see whether this is a relevant concern, subsequent to the examination of changing resource scarcity trends an objective effort is made to identify a long-run equilibrium relationship between natural resource scarcity and economic growth. Relying on cointegration techniques, only for the unit cost measure for lead and copper for one of the measures of cointegration is there a suggestion that natural resource scarcity has affected economic growth in the United States over the period 1889–1992.     

Applying Hybrid ARIMA-SGARCH in Algorithmic Investment Strategies on S&P500 Index

This research aims to compare the performance of ARIMA as a linear model with that of the combination of ARIMA and GARCH family models to forecast S&P500 log returns in order to construct algorithmic investment strategies on this index. We used the data collected from Yahoo Finance with daily frequency for the period from 1 January 2000 to 31 December 2019. By using a rolling window approach, we compared ARIMA with the hybrid models to examine whether hybrid ARIMA-SGARCH and ARIMA-EGARCH can really reflect the specific time-series characteristics and have better predictive power than the simple ARIMA model. In order to assess the precision and quality of these models in forecasting, we compared their equity lines, their forecasting error metrics (MAE, MAPE, RMSE, MAPE), and their performance metrics (annualized return compounded, annualized standard deviation, maximum drawdown, information ratio, and adjusted information ratio). The main contribution of this research is to show that the hybrid models outperform ARIMA and the benchmark (Buy&Hold strategy on S&P500 index) over the long term. These results are not sensitive to varying window sizes, the type of distribution, and the type of the GARCH model.     

Stock Index Prediction Based on Time Series Decomposition and Hybrid Model

The stock index is an important indicator to measure stock market fluctuation, with a guiding role for investors’ decision-making, thus being the object of much research. However, the stock market is affected by uncertainty and volatility, making accurate prediction a challenging task. We propose a new stock index forecasting model based on time series decomposition and a hybrid model. Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) decomposes the stock index into a series of Intrinsic Mode Functions (IMFs) with different feature scales and trend term. The Augmented Dickey Fuller (ADF) method judges the stability of each IMFs and trend term. The Autoregressive Moving Average (ARMA) model is used on stationary time series, and a Long Short-Term Memory (LSTM) model extracts abstract features of unstable time series. The predicted results of each time sequence are reconstructed to obtain the final predicted value. Experiments are conducted on four stock index time series, and the results show that the prediction of the proposed model is closer to the real value than that of seven reference models, and has a good quantitative investment reference value.     

需求弹性在价格决策中的应用

将着眼点由总收益改变为总利润,对于需求弹性用于价格决策,利用微积分方法,分5种情况进行推导,得到的结论修正和补充了现行"经济数学"、"市场营销学"和"管理经济学"等教科书里讲的内容,并在此基础上进一步研究了最佳调价量问题.