长时序高光谱图像清晰度影响因素分析

目的 清晰度是评价对地观测成像仪影像数据质量的典型指标之一,可以反映成像仪对地物边缘变化的敏锐程度。已有的对地观测成像仪在轨测试及图像质量评价方法研究中,往往关注遥感影像清晰度是否达标,或监测其变化趋势,未对清晰度变化影响因素进行深入探讨。针对这一问题,本文主要对长时间序列的成像仪成像清晰度的变化以及影响因素进行探讨。方法 以天宫一号高光谱成像仪短波红外谱段0级数据作为研究对象,首先利用改进的基于边缘检测的清晰度算法计算出影像的清晰度,其次将各影像数据对应的成像仪工程参数进行筛选,然后利用Apriori算法对长时间序列高光谱影像的清晰度与成像时刻的工程参数进行关联规则挖掘,利用最小支持度阈值和最小置信度阈值筛选出强关联规则,并附加提升度和余弦对强关联规则进行验证,最后结合3维散点图对影响清晰度的主要因素进行定量分析。结果 经大量测试数据表明,天宫一号高光谱成像仪短波红外谱段影像清晰度较好,影响清晰度的主要因素有太阳高度角、拍摄积分时间以及平台稳定性(包括俯仰角、偏航角和滚动角的稳定性)。太阳高度角与图像清晰度呈正相关关系,即当太阳高度角大于65°时,影像清晰度较高,当太阳高度角小于30°时,影像清晰度较低;平台稳定性与图像清晰度呈正相关关系,即当太阳高度角大于30°且小于65°时,平台稳定性高倾向于得到清晰度较高的图像,平台稳定性低倾向于得到清晰度较低的图像;拍摄积分时间与图像清晰度呈负相关关系。结论 基于关联规则挖掘的长时序高光谱图像清晰度影响因素分析方法是一种有效的分析方法,可以挖掘出与影像清晰度强关联的工程参数。后续可扩大工程参数范围,利用此分析方法进一步研究遥感图像其他指标与工程参数的关联关系。     

利用抗病基因多样性持续控制水稻病害

 利用抗病基因多样性持续控制水稻病害,已经成为近年来国内外的研究热点之一。由于该技术可大幅度减少农药的施用量,具有明显的增产增收效果,并为实现农业的可持续发展提供了一个崭新的思路,因此得到了国内外科学家和广大农民的普遍认可。作者对这一领域的研究现状、存在的问题及今后的发展前景作一评述。     

抗稻瘟病水稻材料谷梅2号中主效抗稻瘟病基因的成簇分布

应用由籼稻组合中156/谷梅2号衍生的304个重组自交系,构建了由177个标记组成、覆盖12条水稻染色体的连锁图谱,定位控制水稻稻瘟病抗性的主效基因。前期定位的控制对中国稻瘟菌菌系92 183（小种ZC15）穗瘟抗性的基因Pi25(t)的位置得到进一步确认,位于第6染色体标记A7和RG456之间,与A7和RG456的遗传距离分别为1.7和15 cM;发现群体对菲律宾稻瘟菌菌系Ca89（4谱系）的叶瘟抗性由单基因控制,将该暂命名为Pi26(t)的基因定位于第6染色体标记B10和R674之间,与B10和R674的遗传距离分别为5.7和25.8 cM。两个基因座位上的抗病等位基因均来源于谷梅2号,表明谷梅2号中存在控制水稻稻瘟病抗性的基因簇。     

An immunohistochemical study of S-100 protein in the intestinal tract of Chinese soft-shelled turtle, Pelodiscus sinensis

The present work describes the distribution of S-100 protein in the intestinal tract of a Chinese soft-shelled turtle specimen (Pelodiscus sinensis). S-100 protein positive cells were located in the intestinal tract, from the proximal small to distal large intestine. S-100 protein positive dendritic cells had irregular shape and were positive in both cytoplasm and nucleus. Most of them were located both lamina propria and submucosa in the small intestine, while few were found in the large intestine. S-100 protein, C-kit positive ICCs and Silver staining glial cells were predominantly observed in three locations: (1) in the interspace between the submucosa and circular muscle layer; (2) in the circular muscle layer; and (3) between the circular and longitudinal muscle layers of the intestine. Fewer were found in the large intestinal lamina propria and submucosa. Three types of positive cells (S-100 protein positive cells, C-kit positive ICCs and Silver staining glial cells) with 1–2 long or 2–3 short processes were distributed as lace-like or surrounding blood vessels in the different locations mentioned above. In the lamina propria, all the positive cells with irregular processes were connected with each other and formed a network. In the submucosa, all the positive cells were found surrounding the blood vessels.     

解剖采集的珠母贝精子的激活条件

解剖成熟珠母贝（Pinctada margaritifera)并采集其精子，在不同pH、盐度和温度条件下进行激活实验。结果显示，水温25℃、盐度34、pH8.5以下时，珠母贝精子的激活率与活力均很低，pH9.0-10时激活率与活力均较高，pH9.5时的激活率最高；在水温20℃，盐度34时珠母贝精子只能在pH9.5-10激活，且激活率与活力均比25℃时低。在水温25℃，pH9.5时，精子在盐度10-45能激活，盐度25-35时激活率和活力很高；在水温20℃,pH9.5时，精子只能在盐度20-40时激活。当盐度相同，20℃时的激活率与活力比25℃时低，在pH9.5或10的氨海水中，珠母贝精子在水温5-45℃时能激活，在25-30℃时激活率较高。当温度相同，pH9.5时的激活率比pH10.0时高。解剖得到的珠母贝精子的适宜激活pH9.5、适宜盐度为25-35、适宜温度为25-30℃。     

Comparison of L‐lysine·HCl and L‐lysine sulphate in the feed of Penaeus monodon and re‐evaluation of dietary lysine requirement for P. monodon

Two trials were conducted to compare L‐lysine HCl and L‐lysine sulphate regarding its availability to Penaeus monodon, and further evaluate the optimum dietary lysine requirement. In experiment 1, five experimental diets were formulated (D1, D2, D3, D4 and D5), a basal diet (D1), aimed at a low‐lysine concentration (2.22% dry matter), with lysine concentration of the other four diets increasing in two 0.25% L‐lysine intervals from either L‐lysine HCl (D2 and D3) or L‐lysine sulphate (D4 and D5). Each diet was fed at a restricted rate to three groups of 40 shrimp for 74 days. The highest values of growth performance (weight gain, WG; specific growth rate, SGR) and survival were observed with shrimp fed the L‐lysine HCl diet. Feed efficiency (FE) of shrimp fed D2 was significantly higher than that of shrimp fed D1 and D5 (P < 0.05), but without significant difference with shrimp fed D3 and D4 (P > 0.05). In experiment 2, six diets (d1, d2, d3, d4, d5 and d6) were formulated with six graded levels of lysine (2.21%, 2.41%, 2.59%, 2.87%, 3.11% and 3.29% of diet). Each diet was randomly assigned to triplicate groups of 40 shrimp for 74 days. WG, SGR and survival increased increasing levels of lysine up to 2.41% of diet and reached an apparent plateau. Broken‐line model analysis on WG and SGR indicated that the optimum dietary lysine level for optimal growth of shrimp was 2.37% of diet, corresponding to 5.78% of dietary protein. In conclusion, results of this trial suggest that L‐lysine HCl is superior to L‐lysine sulphate when fed to Penaeus monodon and optimal growth can be obtained at lysine levels corresponding to 2.37% of diet, or 5.78% of dietary protein in this specie.     

Student Opportunity: Short-Term Exposure to International Agriculture

Opportunities abound to apply crop science to solving many of the world’s food problems. International agricultural research centers (IARCs) provide a window through which students can see the need for improved agricultural productivity and briefly experience the rewards of working on difficult but important issues. In today’s world of highly technical graduate education, students find it difficult to obtain exposure to international agriculture due to the extreme constraints on their time. Programs for students that provide a short-term exposure to IARC strategies can have long-term benefits for the student as well as the international center. A short-term student exchange program between a US university and the International Rice Research Institute (IRRI) and a special course on rice (research to production) offered at IRRI provide students with unique insights for averting food riots in the future. Details of these educational efforts are described in this paper.     

Growth and blood chemistry of Atlantic halibut (<Emphasis Type="Italic">Hippoglossus hippoglossus</Emphasis> L.) in relation to salinity and continuous light

In order to study the possible interactive effects of salinity and photoperiod on growth, feed conversion, and blood chemistry in juvenile halibut, 2,604 (initial mean weight 26.8 g ± 0.2 SEM) juvenile halibut were exposed to six different combinations of salinities (13, 21, or 27‰) and photoperiods [continuous light, C and simulated natural photoperiod (65°N), SNP] for 129 days. Improved (10–20%) growth and 10–24% higher feed conversion efficiency were observed at low and intermediate salinities compared to the high salinity groups. Improved feed conversion efficiency (20%) and temporary growth enhancing effects (10%) of continuous light were observed, but effects faded out as day length in the simulated natural photoperiod group increased. No interactive effects of photoperiod and salinity on growth feed conversion or measured blood chemistry variables (blood sodium, pH level, haematocrit, bicarbonate content, and total carbon dioxide). It is suggested that juvenile Atlantic halibut should be reared at low and intermediate salinities and at continuous light, as this will improve growth and increase feed conversion efficiency.     

Essay of Different Extraction Procedures in Capelin Fish Meal for Biogenic Amine Determination by HPLC

This study assesses the effects of different extraction procedures of biogenic amines in capelin fish meal with different concentrations of trichloroacetic acid (TCA) for their determination by high performance liquid chromatography (HPLC). No significant differences were noted between the use of TCA at 7.5 and 10% for the extraction of biogenic amines in E1 and E3 extraction, except for tyramine. The extraction using 7.5% TCA in one step and centrifugation (E1) was a simple and rapid method. This extraction seems to be the most suitable for the extraction of amines in these kinds of samples, compared to the other methods tested. The biogenic amine that presented the highest levels in the fish meal studied was cadaverine (208–226 mg/kg), followed by putrescine and histamine (164–173 and 44–46 mg/kg, respectively). Biogenic amine levels were low when compared to the toxic levels observed in these kinds of products.