上市公司产权差异与财政政策异质性研究——基于动态随机一般均衡模型的分析

财政政策对上市公司的影响一直是一项具有研究价值的课题,深入探讨财政政策对上市公司的影响具有必要性。文章构建不同产权的上市公司的动态随机一般均衡模型以讨论财政政策通过影响上市公司的融资约束进而影响托宾Q值,并且探究该影响对不同所有制类型的上市公司产生的异质性效果。研究发现,相较于国有上市公司,减税政策发挥的支持作用对非国有上市公司的作用更大,并且非国有上市公司对政策的敏感性更强且反应程度更大;而政府购买政策仅对国有上市公司进行冲击时才能影响托宾Q值。文章结论表明政府应该加强财政政策对非国有上市公司的支持力度,尤其在极端的经济环境之下,当货币政策的效果有限时,财政政策更应该发挥其特殊作用。

Effects of gastric pacing on gastric emptying and plasma motilin

AIM:To investigate the effects of gastric pacing on gastric emptying and plasma motilin level in a canine model of gastric motility disorders and the correlation between gastric emptying and plasma motilin level.METHODS: Ten healthy Mongrel dogs were divided into:experimental group of six dogs and control group of four dogs. A model of gastric motility disorders was established in the experimental group undergone truncal vagotomy combined with injection of glucagon. Gastric half-emptying time (GEt1/2) was monitored with single photon emission computerized tornography (SPECT), and the half-solid test meal was labeled with an isotope-^99mTc sulfur colloid. Plasma motilin concentration was measured with radioimmunoassay (RIA) kit. Surface gastric pacing at 1.1-1.2 times the intrinsic slow-wave frequency and a superimposed series of high frequency pulses (10-30Hz) was performed for 45min daily for a month in conscious dogs.RESULTS:After surgery, GEt1/2 in dogs undergone truncal vagotorny was increased significantly from 56.35±2.99min to 79.42±1.91min (P<0.001), but surface gastric pacing markedly accelerated gastric emptying and significantly decreased GEt1/2 to 64.94±1.75min (P<0.001) in animals undergone vagotomy. There was a significant increase of plasma level of motilin at the phase of IMCⅢ (interdigestive myoelectrical complex, IMCⅢ) in the dogs undergone bilateral truncal vagotomy (baseline vsvagotomy, 184.29±9.81pg/ml vs 242.09±17.22pg/ml;P<0.01).But plasma motilin concentration (212.55±11.20pg/ml; P<0.02) was decreased significantly after a long-term treatment with gastric pacing.Before gastric padng, GEt1/2 and plasma motilin concentration of the dogs undergone vagotomy showed a positive correlation (r=0.867, P<0.01), but after a long-term gastric pacing, GEt1/2 and motilin level showed a negative correlation (r=-0.733, P<0.04).CONCLUSION: Surface gastric pacing with optimal pacing parameters can improve gastric emptying parameters and significantly accelerate gastric emptying and can resume or alter motor function in a canine model of motility disorders. Gastric emptying is correlated well with plasma motilin level before and after padng, which suggests that motilin can modulate the mechanism of gastric pacing byaltering gastric motility.motilin can modulate the mechanism of gastric pacing by altering gastric motility.

Screening of differentially expressed microRNA in ulcerative colitis related colorectal cancer

Objective:To investigate the differential expression of microRNA(miRNA)in colon between ulcerative colitis(UC)and ulcerative colitis related colorectal cancer(UCRCC).Methods:An UC mouse model was built by dextran sodium sulfate,and an UCRCC mouse model by dextran sodium sulfate and 1,2-diformylhydrazine.RNAs were extracted from the colon,purified and hybridized with fluorescence-labeled miRNA oligonucleotide gene chip.Real-time fluorescence quantitative PCR was used to verity the expression variation of miRNA.SAM was employed for the data analysis.Results:The up-regulated miRNA in colon cancer included has-miR-194,hasmiR-215,has-miR-93,has-miR-192,has-miR-92a,has-miR-29b,and has-miR-20a(median false discovery rate<5%),while the down-regulated miRNAs were has-miR-1231,has-miR-195,has-miR-143,and has-miR-145(median false discovery rate<5%).Conclusions:Significant differential expression of miRNA was found between the UC mouse and UCRCC mouse,which may be related to the onset,erosion and transfer of colorectal cancer.