FAST灵敏度优化及“回照”方式分析

针对500 m口径球面射电望远镜的灵敏度优化和天顶角超过26.4°时溢损增大引起系统噪声温度上升的问题。文中采用调整馈源照明进行灵敏度优化,提出"回照"方式降低系统噪声管温度的方法。当馈源为高斯照明时,边缘照明约为-12^-14 d B时点源观测的灵敏度达到极大值。在天顶角为30°、35°和40°时,分别选取最佳回照角为15°、21°和26°时,望远镜的灵敏度分别提高了19%、48%和100%。

RESEARCH ON COLOR CONSTANCY UNDER OPEN ILLUMINATION CONDITIONS

Color information plays a key role in the research fields of object recognition and image retrieval. However, the actual color varies by the conditions of illumination, especially the open natural daylight. Four different color constancy schemes are proposed in the paper to minimize the effects of open illumination conditions. (1) The color constancy scheme based on the image statistics is proposed, which includes the color cast detection and removal. (2) The color constancy scheme based on the color temperature curve is proposed, which combines Gaussian model with linear fitting to estimate color temperature curve. (3) The color constancy scheme based on the double exposure theory is proposed, which is able to reproduce a color image under typical illumination. (4) According to the concepts of supervised learning, the supervised color constancy scheme is proposed. The transformation of color values from unknown illumination to typical illumination is solved by improved Support Vector Regression (SVR).

Vascular endothelial growth factor polymorphisms and risk of lung cancer

Objective:We investigated the potential association between vascular endothelial growth factor(VEGF) polymorphisms and the risk of lung cancer.Methods:In the case-control study, we used PCR-RFLP technique to determine two VEGF genotypes-2578C/A and 936C/T in 171 lung cancer patients and 172 healthy controls for conformation, and constructed haplotypes of the two gene sites by PHASE1.0 software.Unconditional logistic regression model was used to analyze the statistical association of genontypes or haplotypes in the two groups adjusted by gender and age.Results:Compared with at least one-2578A allele, individuals with-2578CC genotype found associated with a significantly decreased risk of lung cancer P=0.001;adjusted odds ratio(OR), 0.391;95% confidence interval(95% CI), 0.226-0.686.Analyses stratified by gender showed that the combined-2578 CA and AA genotype were also associated with a significantly decreased risk of lung cancer.(P = 0.016;OR = 0.303;95% CI = 0.153-0.601 and P = 0.018;OR = 0.547;95% CI = 0.331-0.903, respectively).The distribution of the two haplotypes(936C/-2578C and 936C/-2578A) were significantly different between case-and-control groups(P = 0.016, OR = 0.317, 95% CI = 0.124-0.809 and P = 0.018, OR = 0.547, 95% CI = 0.331-0.903).Analyses categorized by tumor histology showed that Haplotype C-C was associated with a significantly decreased risk of adenocarcinoma compared with the reference haplotypes.(P = 0.004;OR = 0.237;95% CI = 0.090-0.627).Conclusion:These results suggest that the VEGF polymorphisms may be a critical factor for the risk of lung cancer.

“Four Sacral Needles” Therapy for Female Stress Incontinence

Objective： To make a retrospective control study of the curative effects of ＂Four sacral needles＂ method and conventional acupuncture therapy on female stress incontinence. Methods：A treatment group was treated by ＂Four sacral needles＂ method, in which four sacral points were electroacupunctured with special insertion of needles to excite the pudendal nerve and induce the rhythmic contraction of the pelvic floor muscles, thereby increasing the strength of the pelvic floor muscles and improving ability in urinary continence. A control group was treated by conventional acupuncture therapy, in which corresponding points were acupunctured according to syndrome-based classification. Results： In the 31 cases of the treatment group treated by ＂Four sacral needles＂ method, 100% symptom improvement occurred in 22（71.0% ）after an average of 21 treatments （3-63 treatments）. In the 34 cases of the control group treated by conventional acupuncture therapy, 100% symptom improvement occurred in 0 after 30 treatments. The curative effect was better in the treatment group than in the control group（p〈 0.01）.The curative effect improved with an increase in the number of treatments in the treatment group. Conclusion： ＂Four sacral needles＂ method is more effective than conventional acupuncture therapy in treating female stress incontinence.