Prediction of algal blooms using genetic programming   总被引：2，自引：0，他引：2  

C. Sivapragasam  Nitin Muttil  V.M. Arun 《Marine pollution bulletin》2010,60(10):1849-1855

In this study, an attempt was made to mathematically model and predict algal blooms in Tolo Harbor (Hong Kong) using genetic programming (GP). Chlorophyll plays a vital role in blooms and was used in this model as a measure of algal bloom biomass, and eight other variables were used as input for its prediction. It has been observed that GP evolves multiple models with almost the same values of errors-of-measure. Previous studies on GP modeling have primarily focused on comparing GP results with actual values. In contrast, in this study, the main aim was to propose a systematic procedure for identifying the most appropriate GP model from a list of feasible models (with similar error-of-measure) using a physical understanding of the process aided by data interpretation. Evaluation of the GP-evolved equations shows that they correctly identify the ecologically significant variables. Analysis of the final GP-evolved mathematical model indicates that, of the eight variables assumed to affect algal blooms, the most significant effects are due to chlorophyll, total inorganic nitrogen and dissolved oxygen for a 1-week prediction. For longer lead predictions (biweekly), secchi-disc depth and temperature appear to be significant variables, in addition to chlorophyll.  相似文献   

The scientific rationale for the C1XS X-ray spectrometer on India's Chandrayaan-1 mission to the moon   总被引：1，自引：0，他引：1  

I.A. Crawford  K.H. Joy  B.J. Kellett  M. Anand  N. Bhandari  L. d’Uston  O. Gasnault  C.J. Howe  D. Koschny  B.J. Maddison  S. Narendranath  T. Okada  S.S. Russell  B. Swinyard  M. Wilding 《Planetary and Space Science》2009,57(7):725-734

The UK-built Chandrayaan-1 X-ray Spectrometer (C1XS) will fly as an ESA instrument on India's Chandrayaan-1 mission to the Moon, launched in October 2008. C1XS builds on experience gained with the earlier D-CIXS instrument on SMART-1, but will be a scientifically much more capable instrument. Here we describe the scientific objectives of this instrument, which include mapping the abundances of the major rock-forming elements (principally Mg, Al, Si, Ti, Ca and Fe) in the lunar crust. These data will aid in determining whether regional compositional differences (e.g., the Mg/Fe ratio) are consistent with models of lunar crustal evolution. C1XS data will also permit geochemical studies of smaller scale features, such as the ejecta blankets and central peaks of large impact craters, and individual lava flows and pyroclastic deposits. These objectives all bear on important, and currently unresolved, questions in lunar science, including the structure and evolution of any primordial magma ocean, as revealed by vertical and lateral geochemical variations in the crust, and the composition of the lunar mantle, which will further constrain theories of the Moon's origin, thermal history and internal structure.  相似文献   

Fenton‐Type Oxidative Degradation of N,N‐Diethyl‐p‐phenylenediamine by a Mesoporous Wormhole Structured FeTUD‐1 Catalyst          下载免费PDF全文

Muthusamy Poomalai Pachamuthu  Sekar Karthikeyan  Ganesan Sekaran  Rajamanickam Maheswari  Anand Ramanathan 《洁净——土壤、空气、水》2015,43(3):375-381

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Feeder and post Deccan Trap dyke activities in the northern slope of the Satpura Mountain: Evidence from new 40Ar-39Ar ages     

J.P. Shrivastava  R. Kumar  N. Rani 《地学前缘(英文版)》2017,8(3):483-492

We present new 40Ar-39 Ar plagioclase crystallization ages from the dykes exposed at the northern slope of the Satpura Mountain range near Betul-Jabalpur-Pachmarhi area,~800 km NE of the Western Ghats escarpment.Among the two plateau ages,the first age of 66.56±0.42 Ma from a dyke near Mohpani village represents its crystallization age which is either slightly older or contemporaneous with the nearby Mandla lava flows(63-65 Ma).We suggest that the Mohpani dyke might be one of the feeders for the surrounding lava flows as these lavas are significantly younger than the majority of the main Deccan lavas of the Western Ghats(66.38-65.54 Ma).The second age of 56.95±1.08 Ma comes from a younger dyke near Olini village which cuts across the lava flows of the area.The age correlates well with the Mandla lavas which are chemically similar to the uppermost Poladpur,Ambenali and Mahabaleshwar Formation lavas of SW Deccan.Our study shows that the dyke activities occurred in two phases,with the second one representing the terminal stage.  相似文献   

Vertical bearing capacity behaviour of single T-shaped soil–cement column in soft ground: laboratory modelling,field test,and calculation     

Yaolin Yi  Songyu Liu  Anand J. Puppala  Peisheng Xi 《Acta Geotechnica》2017,12(5):1077-1088

The T-shaped soil–cement column is a variable-diameter column, which has an enlarged column cap at the shallow depth, resulting in the column shape being analogous to the letter “T”. In this study, 1-g laboratory and full-scale field loading tests were employed to investigate the vertical bearing capacity behaviour of a single T-shaped column in soft ground. Pressure cells were set in a T-shaped column in the field to measure the vertical column stress above and below the column cap during the loading test. After the loading test, several columns were excavated to investigate their failure modes. The results indicated that, since the section area of the column cap was remarkably higher than that of the deep-depth column, the stress concentration occurred in the deep-depth column just under the cap, leading to column failure. Based on this failure mode, a simplified method was proposed to estimate the ultimate bearing capacity of a single T-shaped column; the comparison of estimated and measured results indicated the applicability of the proposed method.  相似文献   

Geochemistry of eclogites of the Tso Morari complex,Ladakh, NW Himalayas:Insights into trace element behavior during subduction and exhumation     

Mallika K.Jonnalagadda  Nitin R.Karmalkar  Raymond A.Duraiswami 《地学前缘(英文版)》2019,10(3):811-826

Whole rock major and trace element compositions of seven eclogites from the Tso Morari ultra-high pressure(UHP) complex, Ladakh were determined with the aim of constraining the protolith origins of the subducted crust. The eclogites have major element compositions corresponding to sub-alkaline basalts. Trace element characteristics of the samples show enrichment in LILE's over HFSEs(Rb, Th, K except Ba) with LREE enrichments((La/Lu)n = 1.28-5.96). Absence of Eu anomaly on the Primitive Mantle normalized diagram suggests the absence of plagioclase fractionation. Positive correlation between Mg# with Ni and Cr suggests olivine fractionation of mantle melts. Narrow range of(La/Yb)n(2.1-9.4) and Ce/Yb(6.2-16.2) along with Ti/Y(435-735) ratios calculated for the Tso Morari samples is consistent with generation of melts by partial melting of a garnet free mantle source within the spinel peridotite field. Ternary diagrams(viz. Ti-Zr-Y and Nb-Zr-Y) using immobile and incompatible elements show that the samples range from depleted to enriched and span from within plate basalts(WPB)to enriched MORB(E-MORB) indicating that the eclogite protoliths originated from basaltic magmas.Primitive Mantle normalized multi element plots showing significant Th and LREE enrichment marked by negative Nb anomalies are characteristic of continental flood basalts. Positive Pb, negative Nb, high Th/Ta, a narrow range of Nb/La and the observed wide variation for Ti/Y indicate that the Tso Morari samples have undergone some level of crustal contamination. Observed geochemical characteristics of the Tso Morari samples indicate tholeiitic compositions originated from enriched MORB(E-MORB) type magmas which underwent a limited magmatic evolution through the process of fractional crystallization and probably more by crustal contamination. Observed geochemical similarities(viz. Zr, Nb, La/Yb, La/Gd,La/Nb, Th/Ta ratios and REE) between Tso Morari eclogites and the Group I Panjal Traps make the trap basalt the most likely protoliths for the Tso Morari eclogites.  相似文献   

Improving a thermal conductivity model of unsaturated soils based on multivariate distribution analysis     

Zou  Haifeng  Zhang  Nan  Puppala  Anand J. 《Acta Geotechnica》2019,14(6):2007-2029

Soil thermal conductivity (k) is a key parameter for the design of energy geo-structures, and it depends on many soil properties such as saturation degree, porosity, mineralogical composition, soil type and others. Capturing these diversified influencing factors in a soil thermal conductivity model is a challenging task for engineers due to the nonlinear dependencies. In this study, a multivariate distribution approach was utilized to improve an existing soil thermal conductivity model, Cote and Konrad model, by quantitatively considering the impacts of dry density (ρ_d), porosity (n), saturation degree (S_r), quartz content (m_q), sand content (m_s) and clay content (m_c) on thermal conductivity of unsaturated soils. A large database containing these seven soil parameters was compiled from the literature to support the multivariate analysis. Simplified bivariate and multivariate correlations for improving the Cote and Konrad model were derived analytically and numerically to consider different influencing factors. By incorporating these simplified correlations, the predicted k values were more concentrated around the measured values with the coefficient of determination (R²) increased from 0.83 to 0.95. It is concluded that the developed correlations with the information of different soil properties provide an efficient, rational and simple way to predict soil thermal conductivity more accurately. Moreover, the quartz content is a more important factor than the porosity that shall be considered in the establishment of thermal conductivity models for unsaturated soils with high quartz content.

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Petrogenesis of group A eclogites and websterites: evidence from the Obnazhennaya kimberlite,Yakutia     

Lawrence?A.?TaylorEmail author  Gregory?A.?Snyder  Randall?Keller  David?A.?Remley  Mahesh?Anand  Rene?Wiesli  John?Valley  Nikolai?V.?Sobolev 《Contributions to Mineralogy and Petrology》2003,145(4):424-443

Mantle xenoliths from the Obnazhennaya kimberlite pipe, Yakutia, possess a large range of mineralogical and chemical compositions, from both group A and B eclogites. Major-element contents of the group A eclogites exhibit transitional features between the group B eclogites and peridotite. The Mg# of clinopyroxenes is 0.86–0.94, with 0.60–0.84 for garnets. Differences in concentration of LREEs exist between the Obnazhennaya group A and the well-studied group B eclogites from the Udachnaya kimberlite pipe. In general, garnets in the group A eclogites contain lower LREEs than those from the group B eclogites; however, the trend for clinopyroxene is reversed. High d ¹⁸O (5.46–7.81) values, and the positive Eu anomalies in the garnets and clinopyroxenes (Eu/Eu* 1.2–1.4) demonstrate the involvement of an oceanic crustal component in the formation of the group A eclogites. The group A eclogites formed between 21.0 and 37.6 kbar, and 711 and 923 °C, in a time interval of 1,071–1,237 Ma. An innovative model is proposed to explain the formation of the group A eclogites and websterites. It involves the reaction of a depleted mantle peridotite with TTG and carbonatite melts closely related to the subduction of oceanic crust.  相似文献   

Effects of γ-Rays on Hatching' of the Eggs and Survival Period of Fries of Cyprinus carpio     

R. S. Shrivastava  P. Dwivedi 《洁净——土壤、空气、水》1980,8(4):311-317

The eggs of Cyprinus carpio were irradiated by 5 different strengths: 0.0258, 0.129, 0.258, 0.516 and 1.29 C/kg (100, 500, 1000, 2000 and 5000 R) of γ-rays in the batches of 50 fertilized eggs. The activities of eggs and hatched fries were noted after irradiation doses. The hatching percentages of the eggs were reported for each group. The percentage of hatched eggs of Cyprinus carpio after radiation doses of 0.0258, 0.129, 0.258, 0.516 and 1.29 C/kg (100, 500, 1000, 2000 and 5000 R) was 30%, 24%, 28%, 30%, and 34%, respectively. The 50% mortality period of fries for the above strengths of the γ-rays was 8 days, 7 days, 6 days. 4 days and 4 days, respectively. The survival period of the fries was 11 days, 9 days, 8 days, 7 days and 6 days, respectively. All fries hatched from the eggs irradiated by γ-rays showed early hatching, a higher percentage of mortality, a retarded and abnormal development of the body. A statistical analysis of the results by the correlation coefficient also proved that the hatching percentages of the fries and the survival period of fries are directly proportional to the strength of the γ-rays and inversely proportional to the strength of γ-rays, respectively.  相似文献   

Hot-fluid Driven Metasomatism of Samalpatti Carbonatites, South India: Evidence from Petrology, Mineral Chemistry, Trace Elements and Stable Isotope Compositions     

Rajesh K. Srivastava  Anand Mohan  Cesar Fonseca Ferreira Filho 《Gondwana Research》2005,8(1):77-85

The magmatic heritage of carbonatites can be identified on the basis of a combination of geological criteria such as, their mode of occurrence, the nature of associated igneous rocks, the presence of minerals of igneous origin, fenitization, characteristic trace element contents and isotopic composition. Late Proterozoic Samalpatti carbonatites were studied in view of these criteria, and were found to contain metamorphic minerals that normally form under thermal metamorphic conditions and which have unusual chemical compositions. A combination of criteria points clearly to a magmatic origin for these carbonatites. Field relations indicate that the dominant modes of intrusion of carbonatite into the encompassing pyroxenites and syenites include small dykes, veins, or lenses. The igneous nature of these carbonatites has been described elsewhere and chemically they are classified as calico-carbonatites. Currently, very little is known about the metamorphic textures and mineralogy observed in the Samalpatti carbonatites. In this study, several metamorphic minerals are reported including diopside, grossularite, vesuvianite, K-feldspar and wollastonite, and a hornfelsic texture is described. These mineral phases and texture characterize thermal metamorphism under low pressure and high temperature (LP-HT) metamorphic conditions (650°_750°C) or metasomatism aided by hot-fluid advection. The metamorphic nature of minerals reported is also confirmed by electron microprobe study. The Samalpatti carbonatite samples show much lower values of characteristic trace elements (P, Sr, Ba, Zr, Nb, Th, Y and REEs) than average concentrations for magmatic carbonatite. Stable isotopic (d¹³C and d¹⁸O) compositions of Samalpatti carbonatites do not fall in the primary igneous carbonatite (PIC) domain. The petrological and chemical signatures of these carbonatites suggest metasomatism in conjunction with fluid advection. Such a metasomatic process may drastically change the chemistry of the rocks in addition to enrichment of heavier stable isotopes. During this metasomatic process, characteristic elements would be dissolved in the high d¹⁸O fluid, and together with Rayleigh fractionation would contribute to enhanced concentrations of ¹³C and ¹⁸O in Samalpatti carbonatites.  相似文献