Farmers’ Choice and Informal Credit Markets in China

Informal credit markets are very active in many developing countries including China. Informal financial associations have become a major channel of borrowing. Using data from the 2006 Rural Household Survey, this paper investigates farmers’ borrowings from both formal and informal sources with higher/lower interest, by looking into both demand and supply of loan. Consistent with the theory and previous studies, age follows an inverted U-shaped pattern in its relationship with the probability of borrowing from informal loan with higher interest. Our study shows that the impact of age disappears for the formal loan participation. In addition, high income and saving imply lower credit constraints. Moreover, household and county characteristics and financial conditions have a large and varying influence on farmers’ borrowing behavior.informal credit, financial constraints, China, Agricultural Finance, Community/Rural/Urban Development, International Development, Q12, C5, G21,

Applicability of the qq-Analogue of Zeilberger's Algorithm

The applicability or terminating condition for the ordinary case of Zeilberger's algorithm was recently obtained by Abramov. For the $q$-analogue, the question of whether a bivariate $q$-hypergeometric term has a $qZ$-pair remains open. Le has found a solution to this problem when the given bivariate $q$-hypergeometric term is a rational function in certain powers of $q$. We solve the problem for the general case by giving a characterization of bivariate $q$-hypergeometric terms for which the $q$-analogue of Zeilberger's algorithm terminates. Moreover, we give an algorithm to determine whether a bivariate $q$-hypergeometric term has a $qZ$-pair.Comment: 15 page

A Telescoping method for Double Summations

We present a method to prove hypergeometric double summation identities. Given a hypergeometric term $F(n,i,j)$, we aim to find a difference operator $L=a_0(n) N^0 + a_1(n) N^1 +...+a_r(n) N^r$ and rational functions $R_1(n,i,j),R_2(n,i,j)$ such that $L F = \Delta_i (R_1 F) + \Delta_j (R_2 F)$. Based on simple divisibility considerations, we show that the denominators of $R_1$ and $R_2$ must possess certain factors which can be computed from $F(n, i,j)$. Using these factors as estimates, we may find the numerators of $R_1$ and $R_2$ by guessing the upper bounds of the degrees and solving systems of linear equations. Our method is valid for the Andrews-Paule identity, Carlitz's identities, the Ap\'ery-Schmidt-Strehl identity, the Graham-Knuth-Patashnik identity, and the Petkov\v{s}ek-Wilf-Zeilberger identity.Comment: 22 pages. to appear in J. Computational and Applied Mathematic

Synergistic Effect of Trehalose and Saccharose Pretreatment on Maintenance of Lyophilized Human Red Blood Cell Quality

Purpose: To investigate the synergistic effect of trehalose and saccharose pretreatment on maintenance of lyophilized human red blood cell (RBC) quality.Methods: RBCs were pre-treated with trehalose and saccharose, and then lyophilized and re-hydrated. Prior to lyophilization and after re hydration, RBC parameters, RBC counts, total hemoglobin concentration, mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), comprehensive deformation index, hemolysis ratio and phosphatidylserine (PS) expression, were determined using a hematology analyzer, an RBC deformation instrument, a spectrophotometer and a flow cytometer, respectively. Superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G-6-PD), and adenosine triphosphatase (ATPase) activities were determined using kits for SOD, ATPase, and G-6- PD assay, respectively.Results: After lyophilization-rehydration, RBC counts and total hemoglobin recovery rates, deformability, and RBC SOD, ATPase, and G-6-PD activities were significantly decreased by 47.24 – 74.65 % (p < 0.01), compared with the normal group. RBC osmotic fragility and PS expression on the outer surface of the RBC membrane were significantly increased by 168.53 and 629.30 % (p < 0.01), respectively, compared with the normal group. RBC MCH and MCV values were not significantly affected by lyophilization rehydration (p > 0.05). Trehalose and saccharose pretreatment significantly reversed the effects of lyophilization-rehydration on these RBC parameters by approximately 13.16 – 211.11 % (p < 0.01), compared with the control group. The combined effects were synergistic.Conclusion: Trehalose and saccharose pretreatment synergistically enhances maintenance of lyophilized RBC quality.Keywords: Trehalose, Saccharose, Lyophilization, Red blood cell, Hematological parameter