Using cytochrome P450 to monitor the aquatic environment: Initial results from regional and national surveys     

Tracy K. Collier  S.Denise Connor  Bich-Thuy L. Eberhart  Bernadita F. Anulacion  Anders Goksoyr  Usha Varanasi 《Marine environmental research》1992,34(1-4)

We are currently analyzing hepatic cytochrome P4501A and associated monooxygenase activities in fish sampled in several regional and national monitoring programs, including the National Benthic Surveillance Project of NOAA's Status and Trends Program, damage assessment studies of the Exxon Valdez oil spill, and intensive surveys of specific embayments, such as Puget Sound, Washington. Thus far, apparent contaminant-related increases in the activities of cytochrome P4501A-dependent monooxygenases have been readily measured in most test species. The results presented in this paper show that, for II species of fish, there is excellent concordance between hepatic activities of aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin-O-deethylase (EROD); moreover, levels of cytochrome P4501A determined by an enzyme-linked immunosorbent assay (ELISA) are also generally concordant with results from catalytic assays. The use of both a catalytic assay and immunoquantitation is recommended, because of the additional quality assurance provided by concurrent use of an immunoquantitation technique, which is desirable in large monitoring programs.  相似文献   

Isolation and characterization of benzo[a]pyrene metabolites formed in vivo by juvenile and adult english sole     

Usha Varanasi  John E. Stein  Marc Nishimoto  Tom Hom 《Marine environmental research》1984,14(1-4)

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Dust motions in quasi-statically charged binary asteroid systems     

Jared M. Maruskin  Julie Bellerose  Macken Wong  Lara Mitchell  David Richardson  Douglas Mathews  Tri Nguyen  Usha Ganeshalingam  Gina Ma 《Celestial Mechanics and Dynamical Astronomy》2013,115(3):281-298

In this paper, we discuss dust motion and investigate possible mass transfer of charged particles in a binary asteroid system, in which the asteroids are electrically charged due to solar radiation. The surface potential of the asteroids is assumed to be a piecewise function, with positive potential on the sunlit half and negative potential on the shadow half. We derive the nonautonomous equations of motion for charged particles and an analytic representation for their lofting conditions. Particle trajectories and temporary relative equilibria are examined in relation to their moving forbidden regions, a concept we define and discuss. Finally, we use a Monte Carlo simulation for a case study on mass transfer and loss rates between the asteroids.  相似文献   

Geospatial mapping of potential recharge zones in parts of Pune city     

Raymond A. Duraiswami  Vrishali Dumale  Usha Shetty 《Journal of the Geological Society of India》2009,73(5):621-638

Runoff has increased many fold in urban areas due to increase in paved areas, training of streams and construction of storm water drains. The recharge is therefore continuously decreasing; resulting in depleting groundwater reserves beneath large cities, especially those situated on water divides. In order to reduce surface runoff and replenish groundwater many advocate artificial recharge through rainwater harvesting. Conventionally, detailed hydrogeological survey is needed by expert hydrogeologists to suggest suitable sites for rooftop rainwater harvesting and storage in the subsurface aquifers. Pune, a rapidly growing city, is under severe stress due to shortage of water in some areas. An effort has been made in this study to identify areas suitable for rooftop rainwater harvesting by integrating traditional hydrogeological survey data with the help of Remote Sensing and Geographic Information System. This endeavour has led to develop a program called SLUGGER-DQL which helps to identify potential sites for rooftop rainwater harvesting and artificial recharge. The program is open ended and several other factors controlling potential recharge can be easily added on. Based on the results of the present study, potential sites for rainwater harvesting and artificial recharge have been identified in the Pune University-Shivajinagar-Kothrud area. The present paper demonstrates the utility of traditional hydrogeological surveys combined with modern techniques in solving problems related to urban hydrogeology and town planning.  相似文献   

Management and Maintenance of Forestry:A Catastrophic Stochastic Analysis     

M. A. Shah  Usha Sharma 《Natural Hazards》2001,23(1):49-64

In this paper, we have carried out a detailedstochastic analysis of the Ludwig-Jones–Holling modelpertaining to the occasional population burst ofthe spruce budworms in the coniferous forests of Canada.Our analysis explains the abrupt burst of the populationin the form of cusp catastrophe. A qualitative recipe hasbeen suggested for avoiding the catastrophe.  相似文献   

Shoreline oscillation of Dhanushkodi,Rameswaram, India     

Usha Natesan  R. Vishnunath  K. Kathiravan 《国际地球制图》2015,30(5):520-531

Rameswaram Island located on the southeast coast of India bounded by Gulf of Mannar (GoM) on the south and Palk Bay (PB) on the north, respectively, is unique in nature. The southeastern part of Rameswaram Island known as Dhanushkodi foreland is a long sand spit of about 20?km length. Shoreline erosion/accretion rates are computed based on End-Point Rate, Linear Regression Rate and Net Shoreline Change from Indian Remote sensing Satellite, Linear Imaging Self scanning Sensor III images from 1998 to 2012. Along the PB coast of Dhanushkodi foreland, eroding shorelines are dominant except Arichamunai, whereas it is reversing along GoM. Inter-annual shoreline change revealed that changing trend and stability of Island are affirmed with statistical approaches. An equilibrium shoreline trend is noticed on both the sides of Dhanushkodi foreland. Annual shoreline change rate indicates erosion and accretion in northern and southern coastline of Dhanushkodi foreland varies, respectively.  相似文献   

Coastal vulnerability assessment of the future sea level rise in Udupi coastal zone of Karnataka state, west coast of India   总被引：1，自引：0，他引：1  

G.S. Dwarakish  S.A. Vinay  Usha Natesan  Toshiyuki Asano  Taro Kakinuma  Katta Venkataramana  B. Jagadeesha Pai  M.K. Babita   《Ocean & Coastal Management》2009,52(9):467-478

Udupi coast in Karnataka state, along the west coast of India, selected as a study area, is well known for sandy beaches, aquaculture ponds, lush greenery, temples and major and minor industries. It lies between 13°00′00″–13°45′00″ north latitudes and 74°47′30″–74°30′00″ east longitudes, the length of the coastline is 95 km, and is oriented along the NNW–SSE direction. It is vulnerable to accelerated sea level rise (SLR) due to its low topography and its high ecological and touristy value. The present study has been carried out with a view to calculate the coastal vulnerability index (CVI) to know the high and low vulnerable areas and area of inundation due to future SLR, and land loss due to coastal erosion. Both conventional and remotely sensed data were used and analysed through the modelling technique and by using ERDAS Imagine and geographical information system software. The rate of erosion was 0.6018 km²/yr during 2000–2006 and around 46 km of the total 95 km stretch is under critical erosion. Out of the 95 km stretch coastline, 59% is at very high risk, 7% high, 4% moderate and 30% in the low vulnerable category, due to SLR. Results of the inundation analysis indicate that 42.19 km² and 372.08 km² of the land area will be submerged by flooding at 1 m and 10 m inundation levels. The most severely affected sectors are expected to be the residential and recreational areas, agricultural land, and the natural ecosystem. As this coast is planned for future coastal developmental activities, measures such as building regulation, urban growth planning, development of an integrated coastal zone management, strict enforcement of the Coastal Regulation Zone (CRZ) Act 1991, monitoring of impacts and further research in this regard are recommended for the study area.  相似文献   

Stability of triangular equilibrium points in the elliptic restricted problem of three bodies with radiating and triaxial primaries     

A. Narayan  T. Usha 《Astrophysics and Space Science》2014,351(1):135-142

This paper studies the stability of infinitesimal motions about the triangular equilibrium points in the elliptic restricted three body problem assuming bigger primary as a source of radiation and the smaller one a triaxial rigid body. The perturbation technique developed by Bennet (Icarus 4:177, 1965b) has been used for determination of characteristic exponents. This technique is based on Floquet’s Theory for determination of characteristic exponents in the system with periodic coefficients. The results of the study are analytical and numerical expressions are simulated for the transition curves bounding the region of stability in the μ–e plane, accurate to O(e ²). The unstable region is found to be divided into three parts. The effect of radiation parameter is significant. For small values of e, the results are in favor with the numerical analysis of Danby (Astron. J. 69:166, 1964), Bennet (Icarus 4:177, 1965b), Alfriend and Rand (AIAA J. 6:1024, 1969). The effect of radiation pressure is significant than the oblateness and triaxiality of the primaries.  相似文献   

Some aspects of an explanation of the soft x-ray solar emission lines on the basis of a finite-temperature schrödinger equation     

G. P. Malik  Usha Malik  Vijaya S. Varma 《Astrophysics and Space Science》1993,199(2):299-315

We discuss the range of validity of solutions of the Schrödinger equation with a temperaturemodified Coulomb potential. Such a potential, as was recently pointed out, may be relevant to the resolution of the long-standing problem of unidentified solar emission lines. We also consider in detail a predictive test of our approach, and draw attention to some related conceptual issues.  相似文献   

Modeling of aerosol induced snow albedo feedbacks over the Himalayas and its implications on regional climate     

Usha  K. H.  Nair  Vijayakumar S.  Babu  S. Suresh 《Climate Dynamics》2020,54(9):4191-4210

Climate Dynamics - Regional climate model (RegCM-4.6.0) coupled with Community Land Model (CLM4.5), which includes SNow, ICe and Aerosol Radiation (SNICAR) model was used to investigate the effect...  相似文献