4,184 research outputs found

    Change in the room temperature magnetic property of ZnO upon Mn doping

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    We present in this paper the changes in the room temperature magnetic property of ZnO on Mn doping prepared using solvo-thermal process. The zero field cooled (ZFC) and field cooled (FC) magnetisation of undoped ZnO showed bifurcation and magnetic hysteresis at room temperature. Upon Mn doping the magnetic hysteresis at room temperature and the bifurcation in ZFC-FC magnetization vanishes. The results seem to indicate that undoped ZnO is ferromagnetic while on the other hand the Mn doped ZnO is not a ferromagnetic system. We observe that on addition of Mn atoms the system shows antiferromagnetism with very giant magnetic moments.Comment: 5 figure

    A note on the solution of fuzzy transportation problem using fuzzy linear system

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    In this paper, we discuss the solution of a fuzzy transportation problem, with fuzzy quantities. The problem is solved in two stages. In the first stage, the fuzzy transportation problem is reduced to crisp system by using the lower and upper bounds of fuzzy quantities. In the second stage, the crisp transportation problems are solved by usual simplex method. The procedure is illustrated with numerical examples

    Transition from anticipatory to lag synchronization via complete synchronization in time-delay systems

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    The existence of anticipatory, complete and lag synchronization in a single system having two different time-delays, that is feedback delay τ1\tau_1 and coupling delay τ2\tau_2, is identified. The transition from anticipatory to complete synchronization and from complete to lag synchronization as a function of coupling delay τ2\tau_2 with suitable stability condition is discussed. The existence of anticipatory and lag synchronization is characterized both by the minimum of similarity function and the transition from on-off intermittency to periodic structure in laminar phase distribution.Comment: 14 Pages and 12 Figure

    Conservation of an endemic medicinal plant, Anaphalis eliptica DC. by employing plant tissue culture technique

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    The plant species, Anaphalis elliptica DC. (Asteraceae) is a medicinal herb endemic to high hills of Nilgiri Biosphere Reserve, the Western Ghats. The in vitro propagation study of this species by using leaf, node and shoot tip explants, revealed the following results: Among the three explants used, leaf and node responded well for callus and shoot initiations respectively. The leaf explant produced callus effectively (91%) in the MS medium supplemented with BAP and NAA at 2.5 and 0.3 mg/l respectively, whereas the nodal explant produced higher amount of shoots (92%) in the basal medium containing the growth regulator, BAP alone at 3.0 mg/l. The leaf derived callus produced higher (80%) shoot initials and shoot multiplication in the MS medium augmented with BAP and NAA at 3.0 and 0.5mg/l respectively. Similarly, the in vitro nodal derived shoots produced higher shoot multiplication (87%) in MS medium supplemented with BAP at 3.0mg/l. The regenerated shoots of both the explants were successfully rooted on MS medium supplemented with IBA and NAA at 1.0mg/l each. After sequential hardening the leaf callus derived plantlets registered higher survivability rate (80%) in the hardening medium containing decomposed coir waste, perlite and compost in the ratio of 1:1:1 by volume. Similarly, the survivability rate of nodal derived plantlets was higher (84%) in the hardening medium composed by vermicompost and soil in the ratio of 1:1 by volume

    Phase synchronization in time-delay systems

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    Though the notion of phase synchronization has been well studied in chaotic dynamical systems without delay, it has not been realized yet in chaotic time-delay systems exhibiting non-phase coherent hyperchaotic attractors. In this article we report the first identification of phase synchronization in coupled time-delay systems exhibiting hyperchaotic attractor. We show that there is a transition from non-synchronized behavior to phase and then to generalized synchronization as a function of coupling strength. These transitions are characterized by recurrence quantification analysis, by phase differences based on a new transformation of the attractors and also by the changes in the Lyapunov exponents. We have found these transitions in coupled piece-wise linear and in Mackey-Glass time-delay systems.Comment: 4 pages, 3 Figures (To appear in Physical Review E Rapid Communication

    Experimental confirmation of chaotic phase synchronization in coupled time-delayed electronic circuits

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    We report the first experimental demonstration of chaotic phase synchronization (CPS) in unidirectionally coupled time-delay systems using electronic circuits. We have also implemented experimentally an efficient methodology for characterizing CPS, namely the localized sets. Snapshots of the evolution of coupled systems and the sets as observed from the oscilloscope confirming CPS are shown experimentally. Numerical results from different approaches, namely phase differences, localized sets, changes in the largest Lyapunov exponents and the correlation of probability of recurrence (CCPRC_{CPR}), corroborate the experimental observations.Comment: Physical_Review_E_82_065201(R) 201

    Secondary Metabolites and Nutrient Balance in Casuarinas: an Insight Into Protein Competition Model (PCM)

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    The total phenolics, total condensed tannins (TCT), nitrogen (N) and total protein (TP) in needles of Casuarina equisetifolia and Casuarina junghuhniana were studied to understand the carbon-nutrient balance (CNB) and the growth-differentiation balance (GDB) hypotheses. The carbon-nutrient balance (CNB) hypothesis postulates that phenolic levels in plants are determined by the balance between carbon and nutrient availability1. The growth-differentiation balance (GDB) hypothesis2 considers factors that limit growth and differentiation. The production of phenolics dominates when factors other than photosynthate supply are suboptimal for growth (e.g., under nutrient limitation). Resource-based theories assume that the synthesis of defensive compounds is constrained by the external availability of resources and internal trade-offs in resource allocation between growth and defense. It is stated that growth processes dominate over the production of defensive compounds and that more carbon is left for defensive compounds only when plant growth is restricted by a lack of mineral nutrient (emphasized by the CNB hypothesis) or by any factor (according to the GDB hypothesis). Jones and Hartley3 presented a protein competition model (PCM) for predicting total phenolics allocation and content in leaves of higher plants. Protein competition model (PCM) stated that “protein and phenolics synthesis compete for the common, limiting resource phenylalanine,” so nitrogen (N) rather than C is the limiting resource for synthesis of phenolics. In our study, the contents of Total Phenolics, and Total Condensed Tannin (TCT) in needles of C. equisetifolia were higher than the C. junghuhniana. However, Total protein and nitrogen (N) contents were higher in C. junghuhniana than C. equisetifolia. There was a significant negative correlation between Total phenolics, TCT and Total Protein, N contents. Therefore, it is found from the present investigation that C. equisetifolia follows CNB hypothesis. However, C. junghuhniana follows GDB hypothesis, since it contains low defense chemicals viz., phenolics & TCT and high nitrogen and protein contents. Hence, the adaptability of C. equisetifolia in coastal areas and C. junghuhniana in drier inland condition is realized

    A Study the effect of Biofertilizer Azotobacter Chroococcum on the Growth of Mulberry Cropmorus Indica L. and the Yield of Bombyx Mori L

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    The present study was carried out on the effect of biofertilizer Azotobacter chroococcumon the growth of mulberry plantMorusindica L. and larvalweight, cocoon weight, shell weight, shell ratio and effective rate of rearing (ERR) and length of silk filament of the Bombyxmori. Based on growth of mulberry plant, larval weight and the effect of Azotobacter biofertilizer on length of silk filament was more in treated and which was found to be statistically significant at
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