生物地理学优化算法研究

对生物地理学优化算法(biogeography-based optimization,BBO)的研究现状进行了总结,并介绍了一些最新的研究进展。从BBO算法提出的背景出发,讨论了算法的主要思想、算法原理以及算法步骤。论述了该算法的研究进展,包括BBO算法的改进、算法的收敛性分析、BBO算法与其他算法的融合以及BBO算法在优化领域的典型应用,对BBO算法有待研究的问题做了总结。     

Mechanistic peculiarities of the N2O reduction by CH4 over Fe-silicalite

Transient isotopic studies in the temporal analysis of products (TAP) reactor evidenced the importance of the lifetime of oxygen species generated upon N₂O decomposition on extraframework iron sites of Fe-silicalite for methane oxidation at 723 K. Fe-silicalite effectively activates CH₄ when N₂O and CH₄ are pulsed together in the reactor. However, these oxygen species gradually become inactive for methane oxidation as the time delay between the N₂O and CH₄ pulses is increased from 0 to 2 s.     

基于鱼群算法的无线传感网络覆盖优化策略*

无线传感网络是能量受限的网络,有效覆盖和能耗是衡量其性能的两个重要指标。将最大化网络覆盖率和最小化工作节点数作为网络优化目标,建立了网络覆盖优化的数学模型,并利用鱼群算法并行寻优、收敛快速的特性,提出了一种基于鱼群算法的覆盖优化策略。仿真实验表明,该算法能求解最优覆盖工作节点,并可以改进网络节点调度的实时性。     

Remote sensing of structural complexity indices for habitat and species distribution modeling

Spatial distribution models are increasingly used in ecological studies, but are limited by the poor accuracy of remote sensing (RS) for mapping microhabitat (< 0.1 ha) features. Mapping accuracy can be improved by combining advanced RS image-processing techniques with microhabitat data expressed as a structural complexity index (SCI). To test this idea, we used principal components analysis (PCA) and an additive SCI method developed for forest ecology (calculated by re-scaling and summing representative structural variables) to summarize 13 microhabitat-scale (0.04 ha) vegetation structure attributes describing the rare mountain bongo antelope's (Tragelaphus eurycerus isaaci) habitat in Kenya's Aberdare mountains. Microhabitat data were collected in 127 plots: 37 related to bongo habitat use, 90 from 1 km-spaced grid points representing overall habitat availability and bongo non-presence. We then assessed each SCI's effectiveness for discerning microhabitat variability and bongo habitat selection, using Wilcoxon Rank Sum tests for differences in mean SCI scores among plots divided into 4 vegetation classes, and the Area Under the Curve (AUC) of receiver operating characteristics from logistic regressions. We also examined the accuracy of predicted SCI scores resulting from regression models based on variables derived from a) ASTER imagery processed with spectral mixture and texture analysis, b) an SRTM DEM and c) rainfall data, using the 90 grid plots for model training and the bongo plots as an independent test dataset. Of the five SCIs derived, two performed best: the PCA-derived Canopy Structure Index (CSI) and an additive index summarizing 8 structural variables (AI₈). CSI and AI₈ showed significant differences between 5 of 6 vegetation class pairs, strong abilities to distinguish bongo-selected from available habitat (AUCs = 0.71 (CSI); 0.70 (AI₈)), and predicted scores 60-110% more accurate than reported by other studies using RS to quantify individual microhabitat structural attributes (CSI model R² = 0.51, RMSE = 0.19 (training) and 0.21 (test); AI₈ model R² = 0.46, RMSE = 0.17 (training) and 0.19 (test)). Repeating the Wilcoxon tests and logistic regressions with RS-predicted SCI values showed that AI₈ most effectively preserved the patterns found with the observed SCIs. These results demonstrate that SCIs effectively characterize microhabitat structure and selection, and boost microhabitat mapping accuracy when combined with enhanced RS image-processing techniques. This approach can improve distribution models and broaden their applicability, makes RS more relevant to applied ecology, and shows that processing field data to be more compatible with RS can improve RS-based habitat mapping accuracy.     

Limnological features of Funil Reservoir (R.J., Brazil) and indicator properties of rotifers and cladocerans of the zooplankton community

Funil Reservoir receives inflow from a highly industrialized region and acts as a natural sink to pollutants. Among the consequences of the uncontrolled nutrient loading is the constant presence and periodic heavy blooms of Microcystis aeruginosa . This study verified limnological features and zooplankton assemblage of the Funil Reservoir focusing on the environmental-indicator properties of rotifers and cladocerans. The summer bloom of M. aeruginosa caused reductions in water transparency, nitrate and orthophosphate concentrations and raises in chlorophyll a , pH, dissolved oxygen and chemical oxygen demand values. All zooplankton species presented spatial and temporal variations with the exception of the copepods, which were present in all samples. According to canonical correspondence analysis, ammonium was the variable most related to zooplankton variability and different Rotifera and Cladocera assemblages indicated distinct environment conditions. Rotifer taxa associated with increases of water temperature and chlorophyll a concentration were found with high densities during M. aeruginosa blooms. Species of rotifer and cladocerans are suggested as indicators that can be used to identify different physical and chemical gradients or eutrophic increases in Funil Reservoir.     

大港减压渣油超临界萃取物的柱层析分离及GC/MS分析

在大港减压渣油超临界萃取物(DVR SFEF)的GC/MS分析检测中,除了大港减渣1级萃取分F1以外,在其他级分中分析检测出的物种和数量均较少,特别是DVR SFEF 10~SFEF 17的检测结果很不理想。故通过层析柱对DVR SFEF按照标准分析方法进行分离,可以得到饱和分、芳香分、胶质和沥青质在DVR SFEF中的分布规律,以及DVR SFEF所含饱和分、芳香分、胶质和沥青质中链烃、环烷烃和芳烃的含量的变化规律;还检测出了具有高附加值的稀有物质。     

蛋白质组学在水产品品质与安全研究中的应用

蛋白质组学技术在水产品品质与安全研究中已有较多应用。本文介绍了蛋白质组学的研究途径,综述了蛋白质组学在水产品物种鉴定、过敏原检测、致病性和腐败性微生物的检测与鉴定、贮藏加工过程中品质变化机制研究等方面的应用进展,并对其发展方向和应用前景进行了展望。     

固体催化剂催化高酸值鱼油的甲酯化研究

以高酸值鱼油为原料,利用Amberlyst15固体酸催化剂在温和条件下进行酯化反应降低酸值,再由氧化钙固体碱催化剂催化转酯化得到鱼油脂肪酸甲酯。采用正交设计优化反应条件,预酯化：催化剂用量15%,反应温度75℃,n（醇）/n（油）14,反应时间1.5 h,酸值降为3.35 mg/g,二次预酯化酸值降至1.24 mg/g;酯交换：催化剂用量为10%,反应温度65℃,n（醇）/n（油）为6,反应时间为3 h,鱼油甲酯收率为93.7%。     

基于颜色四通道及空间金字塔的鱼类图像检索

随着计算机视觉技术在海洋水产领域中的应用不断加深，鱼类图像检索在渔业资源调查、鱼类行为学分析等方面发挥了巨大的作用。通过研究发现，鱼类图像的背景信息会对鱼类图像检索造成极大干扰，而且鱼类图像中颜色、纹理、形状等特征由于空间位置信息的缺乏而使检索的准确率不高。为解决以上问题，提出了一种新的基于颜色四通道及空间金字塔的鱼类图像检索算法。首先，提取视觉显著性图将鱼类图像的前景和背景分开，从而减少图像背景对检索的干扰；其次，为了使图像特征包含一定的空间位置信息，利用空间金字塔的理论对图像进行分割，在此基础上，将图像转为HSVG四通道图并提取SURF特征；；最后，得到检索结果。为验证所提算法的有效性，在QUT_fish_data数据集和DLOU_fish_data数据集上对算法的查全率、查准率与经典的HSVG算法和显著性分块算法进行对比：在两个数据集上查准率分别比传统的HSVG算法最多分别提高12%和5%，查全率最多分别提高7%和22%；比传统的显著性分块算法查准率最多分别提高15%和5%，查全率最多分别提高36%和22%；从而证明所提算法是有效的，能有效提升鱼类图像的检索效果。     

Characteristics of Fish Sauce Made from Pacific Whiting and Surimi By-products During Fermentation Stage

ABSTRACT: The fermentation condition for producing Pacific whiting fish sauce was static atmospheric fermentation with 25% salt at 50 °C. The effective enzymes in fermentation were heat stable and salt tolerant. Fermentation at 50 °C gave higher yields than at 35 °C. Total nitrogen content of whole fish fermented at 50 °C reached the equivalent level of commercial fish sauce before 15 d, supporting the strong degradation effects of Pacific whiting enzymes at earlier stages. Soluble solid and relative gravity also reached commercial level at 60 d. However, color value of unripened fish sauce was far from commercial fish sauce, indicating that ripening may be necessary to develop proper color. Staphylococcus, Bacillus , and Micrococcus were found as predominant microorganisms during fermentation.