Use of Biotic Community Structure as a Measure of Ecological Degradation

The benthic macroinvertebrate communities of two lotic aquatic habitats,namely,the Churni River(C-R)and the Jalangi River(J-R)were compared in this study.One lotic aquatic system(C-R)was polluted by organic pollutants due to discharge of unprocessed sewage water,while the other(J-R)was not affected by such pollution.Evaluations of various physico-chemical properties of water,sediment and different macroinvertebrate communities of the two tropical lotic systems were done in a period from January,2002 to December,2003.A long term temporal change in the macroinvertebrate communities was recorded due to increase in sediment rH value.Sediment redox potential affected by the anthropogenic activities was found to be an important factor for alteration of macroinvertebrate communities in these aquatic ecosystems.A positive correlation has been established between rH and Margalef index in this study.Potassium and the total count of coliform bacteria in water showed significantly higher values for the polluted Churni River than those for the Jalangi River.Fig 3,Tab 4,Ref

Phytoplanktonic Community of Organically Polluted Tropical Reservoirs in Eastern India

Plankton communities of three reservoirs of India reflect the direct relationship with organic pollution. The assessment of water quality as highly or lowly organically polluted for the three water bodies has been achieved with help of algal community, which can be used as an indicator of organic pollution. Algal pollution indices according to Palmer[1] and Watanabe[2] and based on genus and species were used in rating water samples for high or low organic pollution. Among 26 genera of algae found in India, 20 most frequent and common genera were taken into account for indexing pollution status. Water quality index (WQI) on the basis of weighting and rating of the chemical parameter was also used to correlate the Palmer index with physico-chemical parameters of the three reservoirs. Fig 5, Tab 3, Ref

Time evolution of the matter content of the expanding universe in the framework of Brans-Dicke gravity

A cosmological model has been constructed in the framework of Brans-Dicke(BD) gravity,based on an inter-conversion between matter and dark energy, for a spatially flat universe in the era of pressureless dust. To account for the non-conservation of the matter content, a function of time f(t) has been arbitrarily put into the expression for the density of matter(ρa^3= f(t)ρ_0 a_0~3). By definition, f(t) is proportional to the matter content of the universe. Using suitable ansatzes for the scale factor and scalar field, the functional form of f(t) has been determined from the BD field equations. The scale factor has been so chosen that it would cause a signature flip in the deceleration parameter with time. The function f(t) decreases monotonically with time, indicating a transformation of matter into dark energy. The time dependence of the proportions of matter and dark energy in the universe has been determined. The effect of non-conservation of the matter content upon various cosmological parameters has been explored in the present study. Two models of matter-energy interaction have been proposed and f(t) has been expressed as a function of their interaction term. The dark energy equation-of-state(EoS) parameter has been expressed and analyzed in terms of f(t).

A theoretical analysis of the growth process of an organism and its dependence on various allometric relations

A new mathematical model regarding the growth process of an organism is proposed, based on the role of surplus power (i.e. power intake minus metabolic cost) and having an allometric dependence on mass. Considering its use in growth, a differential equation has been formed, similar to the von Bertalanffy growth function (VBGF). The time dependence of mass and growth rate, obtained from this equation, has been shown graphically to illustrate the roles played by scaling exponents and other parameters. Concepts of optimum mass, saturation mass and the mass corresponding to the highest growth rate have been discussed under the proposed theoretical framework. Information regarding the dependence of effective growth duration on various parameters has been found graphically. The time of occurrence of the highest growth rate and its dependence on various parameters have been explored graphically. A new parameter (ρ) has been defined, which determines the availability of surplus power at different stages of the growth process of an organism. Depending on its value, there can be three distinctly different modes of growth phenomenon, reflected in the change of surplus power with time. The variations of growth and reproduction efficiencies with time and mass have been shown for different values of the scaling exponent. The limitation regarding the practical measurement of growth rate has been discussed using the present model. Some aspects of length-biomass allometry have been explored theoretically and the results have been depicted graphically.

A Simple Statistical Estimation of One’s Performance in an MCQ Examination, Based Upon Mock Test Results, Using Binomial Distribution of Probability

A simple statistical model is proposed regarding the estimation of one’s overall performance in an MCQ examination along with the calculation of probability of obtaining a certain percentage of marks in the same. Using the data obtained from the results of a sufficiently large number of mock examinations, conducted prior to the main examination, certain parameters quantifying one’s knowledge or preparation for the examination has been calculated. Based on those parameters, the probability of obtaining a certain percentage of marks has been computed using the theory of binomial probability distribution. The dependence of this probability function on various parameters has been depicted graphically. A parameter, called the performance index, has been defined in terms of the expectation value and standard deviation of marks computed from probability distribution. Using this parameter, a new parameter called the relative performance index has been defined. This index estimates one’s performance with respect to the best possible performance. The variation of relative performance index with respect to the preparation index has been shown graphically for different parameter values quantifying various aspects regarding the examination and the examinee.