583 research outputs found

    Small space analogues of Valiant\u27s classes and the limitations of skew formula

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    In the uniform circuit model of computation, the width of a boolean circuit exactly characterises the ``space\u27\u27 complexity of the computed function. Looking for a similar relationship in Valiant\u27s algebraic model of computation, we propose width of an arithmetic circuit as a possible measure of space. We introduce the class VL as an algebraic variant of deterministic log-space L. In the uniform setting, we show that our definition coincides with that of VPSPACE at polynomial width. Further, to define algebraic variants of non-deterministic space-bounded classes, we introduce the notion of ``read-once\u27\u27 certificates for arithmetic circuits. We show that polynomial-size algebraic branching programs can be expressed as a read-once exponential sum over polynomials in VL, ie mboxVBPinSigmaRcdotmboxVLmbox{VBP}inSigma^R cdotmbox{VL}. We also show that SigmaRcdotmboxVBP=mboxVBPSigma^R cdot mbox{VBP} =mbox{VBP}, ie VBPs are stable under read-once exponential sums. Further, we show that read-once exponential sums over a restricted class of constant-width arithmetic circuits are within VQP, and this is the largest known such subclass of poly-log-width circuits with this property. We also study the power of skew formulas and show that exponential sums of a skew formula cannot represent the determinant polynomial

    Excretion of lysine by Micrococcus glutamicus

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    Analysis of intracellular and extracellular lysine concentration during lysine fermentation by Micrococcus glutamicus AEC RN-13-6/1 indicated that lysine excretion occurs against a concentration gradient towards the end of the fermentation period. The capacity to excrete lysine against a concentration gradient may be a factor contributing to the high yield of lysine

    Electrical and Magnetic behaviour of PrFeAsO0.8F0.2 superconductor

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    The superconducting and ground state samples of PrFeAsO0.8F0.2 and PrFeAsO have been synthesised via easy and versatile single step solid state reaction route. X-ray & Reitveld refine parameters of the synthesised samples are in good agreement to the earlier reported value of the structure. The ground state of the pristine compound (PrFeAsO) exhibited a metallic like step in resistivity below 150K followed by another step at 12K. The former is associated with the spin density wave (SDW) like ordering of Fe spins and later to the anomalous magnetic ordering for Pr moments. Both the resistivity anomalies are absent in case of superconducting PrFeAsO0.8F0.2 sample. Detailed high field (up to 12Tesla) electrical and magnetization measurements are carried out for superconducting PrFeAsO0.8F0.2 sample. The PrFeAsO0.8F0.2 exhibited superconducting onset (Tconset) at around 47K with Tc({\rho} =0) at 38K. Though the Tconset remains nearly invariant, the Tc({\rho} =0) is decreased with applied field, and the same is around 23K under applied field of 12Tesla. The upper critical field (Hc2) is estimated from the Ginzburg Landau equation (GL) fitting, which is found to be ~ 182Tesla. Critical current density (Jc) being calculated from high field isothermal magnetization (MH) loops with the help of Beans critical state model, is found to be of the order of 103 A/cm2. Summarily, the superconductivity characterization of single step synthesised PrFeAsO0.8F0.2 superconductor is presented.Comment: 15 Pages Text + Fig

    Purification and properties of diaminopimelate decarboxylase of Micrococcus glutamicus

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    Diaminopimelate decarboxylase (EC 4.1.1.20) of Micrococcus glutamicus ATCC 13059 was purified to homogeneity. The enzyme had an apparent molecular weight of 191,000 as determined by gel filtration on Sephadex G-200. At protein concentrations of 20 and 10 μg per ml and in the absence of pyridoxal-5'-phosphate, it dissociated into a species of molecular weight 94,000. The polypeptide chain molecular weight as determined by sodium dodecyl sulphate Polyacrylamide gel electrophoresis was 100,000. The Km formeso diaminopimelate was 0.5 mM and that for pyridoxal-5'-phosphate was 0.6 μM. Sulphydryl groups and pyridoxal-5'-phosphate were essential for activity and stability. The enzyme was inhibited significantly by L-lysine and DL-aspartic β-semialdehyde

    Aspartokinase of a lysine producing mutant of Micrococcus glutamicus

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    Aspartokinase from Micrococcus glutamicus AEC RN-13-6/1 [a homoserine requiring, S-(2-aminoethyl)-L-cysteine resistant, lysine producing strain] was purified 71 fold. The partially purified enzyme was inhibited by L-lysine. L-threonine, L-methionine, L-isoleucine, L-valine and L-phenylalanine activated the enzyme and reversed the inhibition by L-lysine. Aspartokinase activity was not derepressed by growth-limiting concentrations of L-threonine and/or L-methionine. It was not repressed by an excess of L-lysine (20 mM) and/or L-isoleucine (15.3 mM). The degree of activation or inhibition by amino acids was dependant on the composition of the growth medium. This observation is in contrast with the enzyme from the original (non-lysine-producing) strain which was inhibited by lysine or threonine and in a concerted manner by threonine plus lysine

    Development of sugar free cookies with novel biodegradable packaging film

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    The use of alternative sweeteners can help manage weight and normal blood glucose levels of diabetics. Development and standardization of sugar free, low glycemic index and high fibre cookies using wheat flour, oats, trans free bakery shortening, and almonds.  Physiochemical analysis of the raw materials used for cookie preparation and the finished product was conducted.   Cookies were analysed for diameter, height, spread ratio, texture, and water activity. Sensory analysis using semi-trained panellists was done to establish the acceptability of the product. The formulated cookies were well accepted by the semi-trained panellists as well as the people with diabetes who were randomly selected for the study. The overall appearance, texture and flavour of the cookies were moderately liked by the panellists as indicated in the qualitative descriptive analysis. The product did not change much with the storage of 90 days. The cookies were high in dietary fibre (2.5g per serving), out of which ?- glucan, a soluble fibre was found to be 0.8g per serving which offers a healthy alternative for consumers. The biodegradable polymer used for packaging the cookies was prepared using terpolymer. The chemical and physical properties of the polymer were determined using acid value which was between 0.0195 and 0.0200, hydroxyl value; 0.0260 and 0.023 and the molecular weight was in the range of 10,256 ? and 10,000 ? of the terpolymer A and B, respectively. The polymer demonstrated good mechanical strength as well as and water vapours barrier properties to be used as a primary package for cookies

    Efficient removal of methyl orange using magnesium oxide nanoparticles loaded onto activated carbon

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    ABSTRACT. In this work, an activated carbon composite made with magnesium oxide nanoparticles (MgONP-AC) was effectively utilized for methyl orange (MO) adsorption. The effect of pH (6-10), mass of MgONP-AC (0.1-0.3 g/L), initial MO concentration (10-30 mg/L), and temperature (283-323 K) on MO removal was investigated using a central rotatable composite experimental design based on the response surface technique (RSM) at an equilibrium agitation period of 60 min. The studies predicted the optimal MO removal of 98.99% at pH 7.68, MgONP-AC dosage of 0.24 g/L, and starting MO concentration of 15 mg/L, and temperature of 313 K. Furthermore, an artificial neural network (ANN) was utilized to simulate MO adsorption, and it properly predicted MO removal using mean squared error (MSE) and R2 for the testing data. The ANN predicts a maximum removal of 99.63% with ANN with R2 = 0.9926. The kinetic results suited the pseudo-second order kinetic equation, and the data from the equilibrium investigations corresponded well with the Langmuir isotherm (maximum uptake capacity qmax = 346 mg/g). Endothermic, spontaneous, and physical adsorption were discovered during the thermodynamic investigations.   KEY WORDS: Adsorption, Artificial neural network, Experimental design, isotherms, Kinetics, Methyl orange, MgONP-AC   Bull. Chem. Soc. Ethiop. 2022, 36(3), 531-544.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i3.

    Growing degree days requirement of sesame (Sesamum indicum) in relation to growth and phonological development in Western Rajasthan

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    Not AvailableSesame (Sesamum indicum) is a short-day plant and generally requires fairly hot conditions for its optimum growth and yield. Crop growth and development are closely related with growing degree days. Therefore, growing degree days (GDD) requirement for different phenological stages of sesame cv. RT 127 was studied during the kharif seasons of 2010 and 2011 at the Research Farm of Central Arid Zone Research Institute, Jodhpur (Rajasthan). Plant height increased with accumulation of GDD and attained an height of 124 cm after receiving an accumulated GDD of about 1266 C-day during 2010 and similarly, plant height of 132 cm was observed corresponding to 1240 C-day accumulated GDD during crop season 2011. 80 leaves plant-1 were observed corresponding to an accumulated GDD of 970 C-day during crop season 2010 and 92 leaves plant-1 corresponding to 1094 C-day accumulated GDD during 2011. For initiation flowering stage, higher accumulation of GDD (852 C-day) was observed in 2011 as compared to 2010 (673 C-day) crop season. Higher amount of GDD was also observed for physiological maturity in 2011 than 2010. The significant difference in GDD in the year of normal and late sowing year was also proportionately reflected at 50 and 100% flowering. Hence, study revealed that amount of GDD received in sunny day plays an important role for crop growth and maturity rather than days after sowing. An effort on establishment of relationship between GDD and growth and development of sesame crop may be helpful in developing new varieties matching with shifting climatic patterns.Not Availabl

    Predicting Users’ Responses of Public Utility Services - Multivariate and Neural Network Analysis - A Case Study

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    This research addresses the problem of predicting the user’s responses through multivariate choice (MVC) and neural network (NN) frameworks for predicting quality, quantity and overall User satisfaction of public water supply organization, BWSSB (Bangalore Water Supply and Sewerage Board) in Bangalore - India for policy initiatives. The MVC study identifies statistically significant factors that explain users’ loyalty to express satisfaction and voice to express dissatisfaction. The MVC model correctly predicts 85% of satisfied customers across satisfaction dimensions.  Wald test on 1940 responses confirms that there exits cross equation correlation across quality, quantity and overall Users’ satisfaction dimensions and thus appropriateness of MVC framework over traditional logit for predicting the user responses. NN framework outperforms the econometric model with 94% correct classification of user responses. The study opens up potential research opportunities for applying the advanced analytical frameworks for predicting user responses in various public and private settings for Policy initiatives so that the service providers could improve their service delivery

    Users’ Satisfaction of Public Utility Services – Multivariate System Analysis

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    This research develops a multivariate system framework for assessing user satisfaction of public water utility organization in a developing country and predicts quality, quantity and overall user satisfaction for policy initiatives. The model framework is applied to the data collected by Public Affairs Centre (PAC) based on the Citizen Report Card approach pioneered by it. Wald test confirms that there exits cross equation correlation across quality, quantity and overall users’ satisfaction dimensions. Based on the system model, the study identifies statistically significant factors that explain users’ loyalty to express satisfaction and voice to express dissatisfaction of users. Policy initiatives are proposed on key factors to reduce voice factors set so that the service provider could improve its service delivery. The system model correctly predicts 85% of satisfied customers across quality, quantity and overall satisfaction dimensions.  Keywords: Multivariate, Logit, Discrete choice Model, Public Sector Utility service provide
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