Heliophysics Event Knowledgebase for?the?Solar Dynamics Observatory (SDO) and Beyond

The immense volume of data generated by the suite of instruments on the Solar Dynamics Observatory (SDO) requires new tools for efficient identifying and accessing data that is most relevant for research. We have developed the Heliophysics Events Knowledgebase (HEK) to fill this need. The HEK system combines automated data mining using feature-detection methods and high-performance visualization systems for data markup. In addition, web services and clients are provided for searching the resulting metadata, reviewing results, and efficiently accessing the data. We review these components and present examples of their use with SDO data.     

Effects of salinity on anatomical features and physiology of a semi-mangrove plant Myoporum bontioides

The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400 mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400 mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400 mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300 mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.     

Structure and function of soil microbial community in artificially planted Sonneratia apetala and S. caseolaris forests at different stand ages in Shenzhen Bay,China

The present study examined the relationships between soil characteristics, microbial community structure and function in the forests artificially planted with exotic Sonneratia apetala at stand ages of 1-, 2-, 7-, 10- and 14-years and Sonneratia caseolaris of 1-, 4-, 7-, 10- and 14-years in Futian National Nature Reserve, Shenzhen Bay, China. The 7-years old forests of both Sonneratia species reached peak growth and had the highest content of nitrogen and phosphorus, enzymatic activities, including dehydrogenase, cellulase, phosphatase, urease and ß-glucosidase, except arylsulphatase which increased continuously with stand ages. The microbial community structure reflected by phospholipid fatty acid (PLFA) profiles also reached the maximum value in the 7-years old forests and soil bacterial PLFAs in both forests were significantly higher than fungal PLFAs. The canonical correlation analysis revealed that differences in microbial structural variables were significantly correlated to the differences in their functional variables, and the highest correlation was found between the soil enzymatic activities and the content of carbon and nitrogen.     

Effects of hypoxia on biofilms and subsequently larval settlement of benthic invertebrates

Biofilms on submerged surfaces are important in determining larval settlement of most marine benthic invertebrates. We investigated if exposure of biofilms to hypoxia would alter the larval settlement pattern and result in a shift in benthic invertebrate community structure in the field. Biofilms were first exposed to hypoxia or normoxia in laboratory microcosms for 7 days, and then deployed in the field for another 7 days to allow for larval settlement and recruitment to occur. Using terminal-restriction fragment length polymorphism of the 16S rRNA gene, this study showed that hypoxia altered the biofilm bacterial community composition, and the difference between the hypoxic and normoxic treatments increased with the time of exposure period. This study also demonstrated significantly different benthic invertebrate community structures as a result of biofilm exposure to hypoxia and that the hypoxic and normoxic treatments were dominated by Hydroides sp. and Folliculina sp., respectively.     

Free vibration of frame shear wall structures on flexible foundations

The finite strip method is used to study the effect of an elastic foundation on the natural frequencies of coupled frame shear wall structures. The solid wall in the structure is divided into several strip elements, the column is treated as a line element and the effect of the connecting beams is dealt with through the compatibility matrices which transfer their structural properties to the adjacent strip or line elements. The comparison functions which satisfy the boundary conditions of being free at the top and being spring supported at the bottom are used for the displacement field in the longitudinal direction. A series of numerical examples is presented to show the accuracy and applicability of the proposed method.     

Responses of the green-lipped mussel Perna viridis (L.) to suspended solids

Laboratory experiments were conducted to investigate the lethal and sublethal effects of suspended solids on the survival and physiological, behavourial and morphological changes of the green-lipped mussel Perna viridis collected from Tolo Harbour, Hong Kong. Results showed that P. viridis survived in all test conditions of suspended solids from 0 to 1200 mg/l over a period of 96 h. Physiological responses of the green-lipped mussel under 14-d exposure of suspended solids from 0 to 600 mg/l, followed by 14-d recovery in natural seawater, revealed no significant changes (p>0.05) in oxygen consumption and dry gonosomatic index for treatments in different concentrations of suspended solids and exposure time. Changes in clearance rate were only found to be significant (p<0.001) with exposure time. Responses in behavourial and morphological changes of the green-lipped mussel were also studied under similar experimental treatments and exposure time. Byssus production was significantly (p<0.001) related to exposure time. Gill damage, however, was significantly greater in treatments (p<0.001). Present findings suggested that P. viridis could tolerate a high level of suspended solids in the laboratory. There were dose-dependent effects of suspended solids on morphology of gill filaments. Implications of survival and responses of the green-lipped mussel to suspended solids in the marine environment are discussed.     

Transient response of single piles under horizontal excitations

The general time-domain boundary element in cylindrical co-ordinates developed for the study of wave propagation in a layered half-space is extended to the response analysis of single piles under horizontal transient excitations. The pile is treated as a beam, and therefore, only the bending stiffness has to be considered in the analysis. As required by the non-axisymmetric nature of the problem, the soil is modelled by boundary (cylindrical) elements with the vertical, radial and tangential displacements as well as their corresponding tractions as independent variables. The characteristic matrices for the two different types of element can be formed in the usual manner, and they are combined to form the equation of motion for the whole system by virtue of compatibility and equilibrium conditions along the pile-soil interface. The transient responses of a pile under Heaviside loads are found to converge to the static values. Parametric studies are carried out to reveal the influences of pile-soil stiffness ratio (E_p/E_s) and soil layering.     

Effects of heavy metals on oxygen consumption and ammonia excretion in green-lipped mussels (Perna viridis)

Physiological responses (oxygen consumption and ammonia excretion) of the green-lipped mussel (Perna viridis) exposed to four concentrations of Cd (0.15, 0.32, 0.70 and 1.50 ppm) and four concentrations of Zn (0.60, 1.29, 2.79 and 6.00 ppm) were monitored for 21 days. Changes occurred in the ammonia excretion rates and O:N ratios with individual mussels experiencing different metal concentrations over time. Oxygen consumption rate decreased significantly with time for Cd-exposed individuals and also decreased significantly with the interaction between the concentration of Zn and time for Zn-exposed individuals. Although low O:N ratios (<30) were obtained in most of the treatments, no predictable correlation was found between concentrations of metals and values of O:N obtained. The value of using O:N ratio as a stress index is questioned.     

Characterization of sewage sludge and toxicity evaluation with microalgae

Heavy metal contents (Cd, Cr, Cu, Pb, Ni and Zn) of digested sludge, collected from sewage treatment works (Shatin (ST), Shek Wu Hui (SWH), Tai Po (TP) and Yuen Long (YL)) in 1992, 1993 and 1994, were analysed by atomic absorption spectrophotometry after sequential extraction by 1 KNO₃, 0.5 KF, 0.1 Na₄P₂O₇, 0.1 EDTA and 6 HNO₃. It was found that the major forms of Cu, Pb, Ni and Zn were in the sulphide phase, organically-bound phase, adsorbed phase and carbonate phase, respectively. A dinoflagellate (Dunaliella tertiolecta) and a diatom (Thalassiosira sp.) were used as bioindicators to test the toxicity of digested sludge samples collected in 1994. Each of the algae were inoculated to elutriates of digested sludge at different concentrations. The toxicities of the four types of sludge, according to 96 h-IC₅₀s, were ranked as follows: TP > ST > SWH > YL for D. tertiolecta and ST > SWH > TP > YL for Thalassiosira sp. For D. tertiolecta, a significant correlation was found between algal inhibition and ammonium-N, both in sludge (p<0.05) and elutriates (p<0.01).     

Effects of copper on survival, development and growth of Metapenaeus ensis larvae and postlarvae (decapoda: Penaeidae)

Effects of copper on survival, development and growth of the early developmental stages of the penaeid shrimp, Metapenaeus ensis, were studied in the laboratory. High variability in survival rates were observed among animals from different spawners. Larvae exposed to 0.06 and 0.10 mg Cu l⁻¹ over a 10-day period had lower survival rates and exhibited slower development than control animals. No significant treatment effects were found at 0.04 and 0.08 mg Cu l⁻¹. Effects of copper on survival and growth of postlarvae were studied over an 8-day period. Copper concentrations lower than 0.10 mg l⁻¹ did not affect survival rates. Slower growth rates were observed in postlarvae exposed to 0.08 and 0.10 mg Cu l⁻¹.