Toosendanin as one kind of plant pesticide exists in the fruits, barks, and leaves of Melia azedarach L. (chinaberry tree). To obtain toosendanin, the sample was defatted with petroleum ether, extracted with ethanol; then the solution was concentrated, and extracted with ethyl acetate. Uniform design and regression analysis were employed to establish a model of extraction and optimize the proce...

We study differential equations satisfied by modular forms of two variables associated to Γ1×Γ2, where Γi (i = 1, 2) are genus zero subgroups of SL2(R) commensurable with SL2(Z), e.g., Γ0(N) or Γ0(N)∗ for some N . In some examples, these differential equations are realized as the Picard–Fuchs differential equations of families of K3 surfaces with large Picard numbers, e.g., 19, 18, 17, 16. Our ...

Although policymakers often discuss tradeoffs between bank competition and stability, past research provides differing theoretical perspectives and empirical results on the impact of competition on risk. In this paper, we employ a new approach for identifying exogenous changes in the competitive pressures facing individual banks and discover that an intensification of competition materially boo...