The effect of mutagens on M1 population of black gram (Vigno mungo L. Hepper)

This study was carried out with black gram (urdbean) variety TNAUCo(Bg)6 to determine the effects of gamma rays (150, 200, 250, 300 and 350 Gy) and ethyl methane sulphonate (10, 15, 20, 25, 30 mM). Data collected were on seed germination and survival, pollen and seed fertility, plant height, number of primary branches, number of clusters per plant, number of pods per plant, pod length, number of seeds per plant, hundred seed weight and yield per plant in M1 generation. Thereafter, progressive reduction in germination and survival percentage, pollen and seed fertility and yield related traits were observed in the mutagenic treatments. Deleterious effects were more pronounced in higher doses, indicating almost a linear relationship. LD50 values of 41.30 and 43.50% were observed in 20 mM of ethyl methane sulphonate and 250 Gy of gamma rays, respectively. The increasing doses of gamma rays and ethyl methane sulphonate decreased in phenotypic and yield related parameters. The reduction in quantity and yield traits has been attributed to the physiological disturbance or chromosomal damage of the cells of the plant caused by the mutagens. Ethyl methane sulphonate was observed to be more effective than gamma rays as it generated more number of mutants, which later caused higher physical injury.Keywords: Vigna mungo, variety TNAUCo(Bg)6, gamma rays, ethyl methane sulphonate (EMS)

Determination of genetic polymorphism among indigenous and exotic maize inbreds using microsatellite markers

Maize (Zea mays L.) is an important cereal crop of different countries of world. Undoubtedly, the concerted efforts of plant breeders and their breeding strategies have helped to increase the production and productivity to the tune of two to three folds in many crops including maize. Hybrid cultivars have played a vital role in increasing the acreage and productivity of maize. The success in identifying heterotic hybrid in maize hybrid breeding depends on the availability of genetically diverse maize inbred lines developed from different heterotic gene pool. Hence, generation of information on variability of inbreds at genotypic level become necessary. Molecular markers have proven to be a valuable tool for assessing the genetic diversity in many crop species. Simple sequence repeats (SSR) are currently considered as the molecular markers of choice and are rapidly being adapted by plant researchers for precise estimation of diversity. SSR based molecular diversity analysis of 27 maize inbred lines had produced 23 polymorphic alleles from 10 markers with an average of 2.3 alleles per locus and mean polymorphic information content (PIC) of 0.45. The dendrogram generated with hierarchical unweighted pair group method with arithmetic mean (UPGMA) cluster analysis revealed five major clusters at 0.62 similarity coefficient. The information on diversity of inbred lines generated in this study would be much useful in developing heterotic hybrids.Keywords: Maize, inbreds, marker diversity, simple sequence repeats (SSR)African Journal of Biotechnology Vol. 12(39), pp. 5723-572

Photonics and fracture toughness of heterogeneous composite materials

Fracture toughness measures the resistance of a material to fracture. This fundamental property is used in diverse engineering designs including mechanical, civil, materials, electronics and chemical engineering applications. In spite of the advancements made in the past 40 years, the evaluation of this remains challenging for extremely heterogeneous materials such as composite concretes. By taking advantage of the optical properties of a thin birefringent coating on the surface of opaque, notched composite concrete beams, here we sense the evolution of the maximum shear stress distribution on the beams under loading. The location of the maximum deviator stress is tracked ahead of the crack tip on the experimental concrete samples under the ultimate load, and hence the effective crack length is characterised. Using this, the fracture toughness of a number of heterogeneous composite beams is evaluated and the results compare favourably well with other conventional methods using combined experimental and numerical/analytical approaches. Finally a new model, correlating the optically measured shear stress concentration factor and flexural strength with the fracture toughness of concretes is proposed. The current photonics-based study could be vital in evaluating the fracture toughness of even opaque and complex heterogeneous materials more effectively in future

Real Time QRS Detection Based on M-ary Likelihood Ratio Test on the DFT Coefficients

This paper shows an adaptive statistical test for QRS detection of electrocardiography (ECG) signals. The method is based on a M-ary generalized likelihood ratio test (LRT) defined over a multiple observation window in the Fourier domain. The motivations for proposing another detection algorithm based on maximum a posteriori (MAP) estimation are found in the high complexity of the signal model proposed in previous approaches which i) makes them computationally unfeasible or not intended for real time applications such as intensive care monitoring and (ii) in which the parameter selection conditions the overall performance. In this sense, we propose an alternative model based on the independent Gaussian properties of the Discrete Fourier Transform (DFT) coefficients, which allows to define a simplified MAP probability function. In addition, the proposed approach defines an adaptive MAP statistical test in which a global hypothesis is defined on particular hypotheses of the multiple observation window. In this sense, the observation interval is modeled as a discontinuous transmission discrete-time stochastic process avoiding the inclusion of parameters that constraint the morphology of the QRS complexes.This work has received research funding from the Spanish government (www.micinn.es) under project TEC2012 34306 (DiagnoSIS, Diagnosis by means of Statistical Intelligent Systems, 70K€) and projects P09-TIC-4530 (300K€) and P11-TIC-7103 (156K€) from the Andalusian government (http://www.juntadeandalucia.es/organismo​s/economiainnovacioncienciayempleo.html)

Anaerobic digestion of screenings for biogas recovery

Screenings comprise untreatable solid materials that have found their way into the sewer. They are removed during preliminary treatment at the inlet work of any wastewater treatment process using a unit operation termed as a screen and at present are disposed of to landfill. These materials, if not removed, will damage mechanical equipment due to its heterogeneity and reduce overall treatment process, reliability and effectiveness. That is why this material is retained and prevented from entering the treatment system before finally being disposed of. The amount of biodegradable organic matter in screenings often exceeds the upper limit and emits a significant amount of greenhouse gases during biodegradation on landfill. Nutrient release can cause a serious problem of eutrophication phenomena in receiving waters and a deterioration of water quality. Disposal of screenings on landfill also can cause odour problem due to putrescible nature of some of the solid material. In view of the high organic content of screenings, anaerobic digestion method may not only offer the potential for energy recovery but also nutrient. In this study, the anaerobic digestion was performed for 30,days, at controlled pH and temperature, using different dry solids concentrations of screenings to study the potential of biogas recovery in the form of methane. It was found screenings have physical characteristics of 30% total solids and 93% volatile solids, suggesting screenings are a type of waste with high dry solids and organic contents. Consistent pH around pH 6.22 indicates anaerobic digestion of screenings needs minimum pH correction. The biomethane potential tests demonstrated screenings were amenable to anaerobic digestion with methane yield of 355,m3/kg VS, which is comparable to the previous results. This study shows that anaerobic digestion is not only beneficial for waste treatment but also to turn waste into useful resources