基于相关分析的组合导航RAIM模型研究

探讨基于相关分析理论的组合导航RIAM方法,并给出单个和多个探测粗差的相关分析检验流程。通过模拟12颗GPS和Galileo组合导航卫星定位系统,分别给单颗和两颗正常卫星加入粗差。仿真结果表明：观测值的影响向量与残差的相关系数可以定位含粗差的卫星并将粗差卫星予以剔除。     

Nutrient and chlorophyll a anomaly in red-tide periods of 2003-2008 in Sishili Bay, China

Sishili Bay is the most important aquiculture and tourism area for the city of Yantai, China; however, red tides occurred frequently and have caused huge economic losses in this bay in recent years. To gain a better understanding of the local ecological environments in the bay, we conducted this research between 2003 and 2008 to analyze variations in nutrients and chlorophyll (chl-a) during high frequency red tide period (May to September). The results show that the chl-a concentration increased from 2.70 in 2003 to 7.26 mg/m3 in 2008, while the concentration of total inorganic nitrogen (TIN) and silicate (SiO3-Si) increased lineally from 5.18 and 1.45 μmol/L in 2003 to 18.57 and 9.52 μmol/L in 2008, respectively, and the annual phosphate (PO4-P) varied between 0.15 and 0.46 μmol/L. Special attention was given to a red tide in August 2007 occurred when water temperature was high and nutrient concentrations increased sharply because of a heavy rainfall. Overall, the results show the P limitation in Sishili Bay, and reveal that red tides were caused by eutrophication from terrestrial inputs and local warm weather, particularly during rainy periods. Therefore, to control red tide, greater efforts should be made to reduce sewage discharges into Sishili Bay, particularly during rainfall seasons.     

Diurnal variation in relative photosynthetic performance of marestail (Hippuris vulgaris Linn.) Across a water temperature gradient using PAM fluorometry in Jiuzhaigou National Nature Reserve, Sichuan Province, China

This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates (ETR_max) were measured as rapid light curves (RLCs) by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 °C. Nonphotochemical quenching (NPQ) of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield (F _v/F _m) of submerged marestail in Five Colored Lake showed full recovery at 1700 h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highest in Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant’s ecophysiological reactions.     

Phytoplankton pigment patterns and community composition in the northern South China Sea during winter

Phytoplankton pigment patterns and community composition were investigated in the northern South China Sea using high-performance liquid chromatography and the CHEMTAX software from February 11 to 23, 2009. We recognized four different vertical distribution patterns of pigments: chlorophyll a (Chl a)-like type, divinyl chlorophyll a (DV Chl a) type, even distribution type, and surface type. The average value of ratios of accessory photo-protective pigments (APP) to accessory photo-synthetic pigments was 0.89±0.63 in the upper 50 m and 0.16±0.06 below 50 m depth. With increasing depth, APP decreased and photo-synthetically active radiation was attenuated. There was an obvious succession in the phytoplankton community from inshore to the open sea. Diatoms were dominant in the inshore region, while pelagophytes, Prochlorococcus, cyanobacteria and prymnesiophytes were dominant in the open sea. The vertical distribution of phytoplankton also differed greatly from inshore to the open sea. In the coastal and shelf region, diatoms were important components in the whole water column. Cyanobacteria also had a high abundance at the Subsurface Chlorophyll a Maxima (SCM) in the shelf region. In the slope and open sea, Prochlorococcus and cyanobacteria were important groups above the SCM, while pelagophytes dominated below the SCM.     

Identification of five sea cucumber species through PCR-RFLP analysis

Sea cucumbers are traditional marine food and Chinese medicine in Asia. The rapid expansion of sea cucumber market has resulted in various problems, such as commercial fraud and mislabeling. Conventionally, sea cucumber species could be distinguished by their morphological and anatomical characteristics; however, their identification becomes difficult when they are processed. The aim of this study was to develop a new convenient method of identifying and distinguishing sea cucumber species. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of mitochondrial cytochrome oxidase I gene (COI) was used to identifing five sea cucumber species (Apostichopus japonicus, Cucumaria frondosa, Thelenota ananas, Parastichopus californicus and Actinopyga lecanora). A 692 bp fragment of COI was searched for BamHI, KpnI, PstI, XbaI and Eco31I restriction sites with DNAMAN 6.0, which were then used to PCR-RFLP analysis. These five sea cucumber species can be discriminated from mixed sea cucumbers. The developed PCR-RFLP assay will facilitate the identification of sea cucumbers, making their source tracing and quality controlling feasible.     

Historical Sediment Record of ~(137)Cs, δ-HCH,and δ~(13)C Reflects the Impact of Land Use on Soil Erosion

This paper reports the concentrations of 137 Cs, hexachlorocyclohexane(HCH), dichlorodiphenyltrichloroethanes(DDT) and its main degradation products, δ13C, and organic carbon in pond sediments(0-210 cm, sectioned by 2-20 cm interval) and surface soils(the 0-3 cm horizon) collected in 2010 from Chenjia catchment, which is located in Yanting county in the hilly central Sichuan of China. α-, δ-, and γ-HCH, DDT, and DDD were not detected throughout the sediment profile. Trace concentrations of δ-HCH(0.89-29.31 ng g-1) and p,p′-DDE(1.85-6.02 ng g-1) were detected only in top 40 cm sediment. The 137 Cs fallout peak in 1963(corresponding to the 55-60 cm depth), the sedimentary signature left by the last year of HCH use in 1989(an additional indicator at 20-25 cm), and the obvious original channel bed prior to the construction of the pond in 1956 were used as temporal markers to estimate changes in average sedimentation rate between different periods due to changes in land use. Continuous, marked decrease in average sedimentation rate(i.e., 3.79, 1.35 and 1.07 cm year-1 in 1956-1963, 1963-1989, and 1989-2010, respectively)over time was observed, probably due to the reforestation, abandoning of steep sloping farmland for afforestation and natural re-vegetation(implementation of the Grain for Green Program), and the conversion of part of gently sloping farmland terraces to orchard land since the 1980 s, especially since the 1990 s. This was corroborated by the observed decrease(more negative) in δ13C of sediment towards the surface, which indicates increased relative contribution of eroded soil particles coming from slopes with increased tree cover in sediment source area. Combined use of 137 Cs, δ-HCH, and δ13C record in sediments has been demonstrated to be a powerful approach to reconstruction of response in sedimentation rate to historical land use changes.     

Marine bacterium strain screening and pyrethroid insecticide-degrading efficiency analysis

A pyrethroid insecticide-degrading bacterium, strain HS-24, was isolated from an offshore seawater environment. The strain, which can degrade cypermethrin(CYP) and deltamethrin(DEL), was identified as Methylophaga sp. The optimal culture and degradation conditions for CYP and DEL by strain HS-24 is pH 7 at 28°C. Under optimum culture conditions, strain HS-24 exhibited a broad degradation concentration range of 100, 200, 400, 600, and 800 mg/L for CYP and DEL. The metabolic intermediates were analyzed by NMR, which provided strong evidence that CYP and DEL removal occurred mainly because of a biological process. The toxicity of the degradation products of strain HS-24 was studied simultaneously by measuring the light output of the luminescence bacterium. This demonstrated that the biodegradation ability of strain HS-24 significantly decreased the toxicity of CYP- and DEL-contaminated aquaculture seawater. Finally, the findings of this paper indicate that strain HS-24 is thus revealed as a biological agent for the remediation of marine aquatic environments.     

Effects of corridor networks on plant species composition and diversity in an intensive agriculture landscape

The development of modern agriculture has resulted in much homogenization of the landscape consisting of large patches of farmland,so small remnant non-crop habitats especially linear corridors play an important role in the conservation of species and the maintenance of ecosystem functions.However,little attention has been paid to the effects of corridors structural characteristics on the plant species restricted to such habitats.In this study,we selected three types of corridors including ditch,hedgerow and road,and ana-lyzed their structural characteristics.The plant species presented in these corridors were investigated,and the species diversity,abun-dance and frequency were estimated.Moreover,spatial arrangements of corridors were classified into different types to discuss whether there were significant effects of corridor network on plant distribution.The results show that three types of corridors have different ef-fects on plant species composition and diversity.The one-one combined corridor networks and total network associated by three corri-dors have more complex structural features than each single type of corridor.However,there is no strong correlation between the corri-dor networks with their plant species.We suggest that carrying out a pointed vegetation survey at corridor intersections to further test the relationships between structural features of corridor and plants is necessary.     

Characterizing landscape spatial heterogeneity in multisensor images with variogram models

Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index （NDVI） products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has been filled through quantifying and evaluating spatial heterogeneity of urban and natural landscapes from QuickBird, Satellite pour l＇observation de la Terre （SPOT）, Ad- vanced Spacebome Thermal Emission and Reflection Radiometer （ASTER） and Landsat Thematic Mapper （TM） images with variogram analysis. Instead of a logarithmic relationship with pixel size observed in the corresponding aggregated images, the spatial variability decayed and the spatial structures decomposed more slowly and complexly with spatial resolution for real multisensor im- ages. As the spatial resolution increased, the proportion of spatial variability of the smaller spatial structure decreased quickly and only a larger spatial structure was observed at very coarse scales. Compared with visible band, greater spatial variability was observed in near infrared band for both densely and less densely vegetated landscapes. The influence of image size on spatial heterogeneity was highly dependent on whether the empirical sernivariogram reached its sill within the original image size. When the empirical semivariogram did not reach its sill at the original observation scale, spatial variability and mean characteristic length scale would increase with image size; otherwise they might decrease. This study could provide new insights into the knowledge of spatial heterogeneity in real multisen- sor images with consideration of their nominal spatial resolution, image size and spectral bands.     

Detection of lymphocystis disease virus in Japanese flounder Paralichthys olivaceus and other marine teleosts from northern China

We isolated a strain of lymphocystis disease virus (LCDV) from Japanese flounder (Paralichthys olivaceus) cultured in northern China. Based on published sequences of major capsid protein (MCP) gene of LCDV-cn (GenBank: AF126405), we designed two primer sets P1/P2 and P3/P4. We then used one-step or nested PCR and in-situ hybridization (ISH) to detect LCDV and identify the target tissues or cells in infected Japanese flounder. The PCR products were positive in purified viral supernatant, skin nodules, gut, gill, kidney, spleen, stomach, heart, and liver of Japanese flounder. We compared the DNA sequence with 14 MCP nucleotide sequences from GenBank, including Megalocytivirus (OFIV and RSIV), Iridovirus (CzIV and WIV), Ranavirus (TFV and FV3), and Lymphocystivirus (8 LCDV). Based on the alignment, we confirmed the PCR product was from Lymphocystivirus (GenBank accession number DQ279090 (LCDV-HD)). Using ISH, we noted the presence of LCDV in the skin nodules, gut, gill, spleen, stomach, and heart of spontaneously infected Japanese flounders. We successfully amplified LCDV fragments from Schlegel’s black rockfish (Sebastes schlegeli Higendorf), redwing sea robin (Lepidotrigla microptera Günther) and turbot (Scophthalmus maximus) using the one-step and nested PCR, suggesting the target genes can be widely detected in fish using this method.