Archives-December 

The overriding problem with analyzing unbalanced data which leads to heteroscedasity models is that many methods are available and deciding between them can be a matter of some difficulty. Heteroscedasticity is a problem because ordinary least squares (OLS) in regression assumes that all residuals are drawn from a population that has a constant variance (homoscedasticity). When conditional heteroscedasticity is present, the practice of reweighting the data has long been abandoned in favor of estimating model parameters by ordinary OLS, in conjunction with using heteroscedasticity consistent standard errors. However, we argue for reintroducing the practice of reweighting the data, since doing so can lead to large efficiency gains of the resulting weighted least squares WLS estimator over OLS even when the model for reweighting the data is misspecified. The idea is that, the estimator can also be accompanied by the help of type of proportionality condition on cell sample size using harmonic mean. Special emphasis is given to nested model and on the unbalancedness in the data due to heterogeneity in the environmental conditions of experiments. Estimators of the parameters for this model are found to be independent of the weights under this condition.

Residual levels of organophosphorous pesticides were determined in 44 fermented and dried cocoa beans samples collected from two cocoa beans storage warehouses located in Tema and Takoradi; cities in Ghana from November 2010 to January 2011. The main objective of the study was to monitor and assess the residue levels of 13 organophosphorous pesticides in fermented and dried cocoa beans produced from Ghana. The extraction method uses acetonitrile as the extracting solvent. Two solid phase extraction clean-up cartridges were employed; bond elut C18 cartridge, followed by envi-carp/LC-NH2 superclean cartridge; using acetonitrile and a mixture of toluene/acetonitrile in the ratio 1:3 as eluting solvents, respectively. The determination was done using gas chromatography with pulse flame photometric detector (GC-PFPD). The targeted compounds were methamidophos, ethoprophos, phorate, fonofos, diazinon, dimethoate, pirimiphos-methyl, chlorpyrifos, malathion, fenitrothion, parathion, chlorfenvinphos and profenofos. The percentage recoveries ranged from 70-95 percent, with instrumental method determination limit of 5.0 ?g/kg. The results indicated that ethoprophos is not being used in cocoa production in Ghana. However, there were appreciable amounts of Dimethoate (22.3 µg/kg), Pirimiphos-methyl (29.5 µg/kg), Malathion (20.6 µg/kg), Chlorpyrifos (50.2 µg/kg) and Fenitrothion (93.8 µg/kg). These notwithstanding, residue levels of all organophosphorous pesticides detected were below both the EU and Japanese maximum residue limits; with the exception of Methamidophos, Chlorpyrifos, Malathion and Profenofos which average residue values were comparable with either one of the two international maximum residue limits set.

Nature Inspired Computation defined as a computational intelligence paradigm inspired from natural biological systems (such as human brain and neural systems, Genetic Algorithms; Bees and Ants Colonies Optimization, etc........). Recently, this paradigm has been successfully applied for solving computational optimization problems, in many fields (such as, machine learning, and engineering design, etc.........). Moreover, by considering its unique computational intelligence characters of self-adaptive, self-organizing and self-learning. It is relevant to adopt its application for modeling and performance evaluation of educational Systems. Herein, the presented work motivated by recent research publications inspired by two interdisciplinary computational intelligence Models. Both have been characterized by challenged bridging of two Natural inspired Models across an interesting practical educational issue. More specifically, this piece of research concerned with the theoretical analysis and evaluation of constructive bridges of Artificial Neural Networks (ANNs) & Ant Colony Systems (ACS) across Open Learning Systems. Noting that motivating research publications include the following two topics: 1- Assessment of students' adaptability using ANNs models (Cognitive Styles Approach). 2- Modeling of Cooperative e-Learning Performance (ACS Approach).

Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral–solution interface. The bio-modification of mineral surfaces involves the complex action of microorganism on the mineral surface. The manner, in which bacteria affect the surface reactivity and the mechanism of adsorption and accumulation of the primary data in this area are only starting. Bio-Processing involves the selective removal of undesirable mineral constituents from an ore through microbe-mineral interactions in the processes such as selective flotation and flocculation. At the same time, bio-sorption has made a considerable progress in moving from theory to industrial practice as it is not only environmental useful but also more economical than many other processes. The bio-flotation, bio-flocculation and bio-sorption processes concern the mineral response to the bacterium presence, which is essentially interplay between microorganism and the physicochemical properties of the mineral surface, such as the atomic and electronic structures, the net charge/potential, the acid–base properties, and the wettability of the surface. The adhesion of microorganisms to minerals result in alteration of surface chemistry of minerals relevant to beneficiation process due to a consequence of the formation of a biofilm on the surface or bio-catalyzed surface oxidation or reduction products. There is an urgent need for developing basic knowledge that would underpin biotechnological innovations in the natural resource processing technologies that deliver competitive solutions.

Pheochromocytomas are catecholamine producing tumors arising mostly from chromaffin cells of the adrenal medulla. The prevalence of the tumor is 0.1%-0.6% in the hypertensive population, It has been called 'the great mimic’, capable of presenting itself as many other medical conditions. The most common clinical presentation is hypertension, mainly in the form of paroxysmal episodes. Cardiovascular manifestations include malignant arrhythmia and catecholamine cardiomyopathy, mimicking acute coronary syndromes and acute heart failure. We report a case of pheochromocytoma revealed by angina, and acute myocardial infarction without coronary artery disease (CAD).

Age effect, intestinal site and pH influence on phytate hydrolysis were assayed in brush border membrane vesicles isolated from chicks and layers proximal and distal intestinal segments using MgCl2 precipitation and differential centrifugation. The ascertained BBMVs purity and functional integrity depicted alkaline phosphatase enzyme marker to range between 20-fold to 37-fold greater for chicks’ and layers’ proximal and distal BBMVs than in their mucosal homogenates, their integrity suggestive to presence of Na+-dependent transport while electron micrograph showed a vesicular form. Both chicks’ and layers’ BBMVs, had significant decrease in phytate-P hydrolysed/mg.

In this study the energy consumption of orange orchards was surveyed and various Artificial Neural Networks (ANNs) developed to estimate the farmer’s production in the Sari region as a case study. The data were collected using a face-to-face questionnaire method from 86 farmers in the Sari region. The results indicated that the total amount of energy input and output were 54284.8 and 59223.4 MJ ha-1, respectively. Among all inputs involved, diesel fuel had the highest energy values per hectare. Also, energy efficiency, energy productivity and net energy were calculated as 1.09, 0.57 kg MJ-1 and 4938.5 MJ ha-1, respectively. Performance of developed ANN models were evaluated using the coefficient of determination (R2), mean absolute error (MAE) and root mean squared error (RMSE). The resulting tests showed that best performance was achieved by a momentum training algorithm resulting in R2=0.84, and MAE= 0.32 and RMSE=0.38 with 8-4-1 topology. Additionally, sensitivity analysis revealed that fertilizer and electricity energy had the highest and the lowest sensitivity on output, respectively.

There are lots of nonlinear formulas in mathematics and physics and there are, many types of solitons to talk over. This revision is dedicated to the straight technical particulars of how to produce soliton solution of Maxwell's equations and intensive confirmation is placed on mathematical report analysis. The quasi-stationary state waveguides has been founded and with a small deviation from equilibrium, we measured and advanced a solution for a formula. Classical parting of parameters is presented with a special B.C. is introduced on a slab waveguide to obtain a general form of solution of the coordinates x, y z.

Let G be a graph with n vertices. Prime labeling of G is the labeling of the vertices using first n positive integers such that labeling of each pair of adjacent vertices are relatively prime. This work is a generalization of [2] which was analogous to [1] in which prime labeling for complete bipartite graphs were considered. In [2] conditions for the existence of prime labeling of complete tripartite graphs of the form K_(1,m,n) was given where m,n?Z^+. In our work, we have proved that prime labeling of K_(2,m,n) and K_(3,m,n) exists for some values of m and n where m,n?Z^+. Further, few non-existance cases have been discussed.

This paper aims to highlight certain facts that help as well as constrain the production and marketing of coconuts in Karnataka. Based on the observation and analysis of the collected data, the paper concludes that both the production and marketing practices of coconut in Karnataka need to be made more professional if it has to continue to benefit the farmers and to assert its role in the Indian scenario.