Experimental Evidence of Time Delay Induced Death in Coupled Limit Cycle Oscillators

Experimental observations of time delay induced amplitude death in a pair of coupled nonlinear electronic circuits that are individually capable of exhibiting limit cycle oscillations are described. In particular, the existence of multiply connected death islands in the parameter space of the coupling strength and the time delay parameter for coupled identical oscillators is established. The existence of such regions was predicted earlier on theoretical grounds in [Phys. Rev. Lett. 80, 5109 (1998); Physica 129D, 15 (1999)]. The experiments also reveal the occurrence of multiple frequency states, frequency suppression of oscillations with increased time delay and the onset of both in-phase and anti-phase collective oscillations.Comment: 4 aps formatted RevTeX pages; 6 figures; to appear in Phys. Rev. Let

Benfotiamine, a vitamin B1 derivative, inhibits VEGF-induced angiogenesis.

A in-vitro study that indicates that benfotiamine, a vitamin B1 derivative, has anti-angiogenic potential via the inhibition of various pro-angiogenic growth factors and promoting anti-angiogenic factors

Effect of Nonlinear Thermal Radiation on MHD Chemically Reacting Maxwell Fluid Flow Past a Linearly Stretching Sheet

This communication addresses the influence of nonlinear thermal radiation on magneto hydrodynamic Maxwell fluid flow past a linearly stretching surface with heat and mass transfer. The effects of heat generation/absorption and chemical reaction are taken into account. At first, we converted the governing partial differential equations into nonlinear ordinary differential equations with the help of suitable similarity transformations and solved by using Runge-Kutta based shooting technique. Further, the effects of various physical parameters on velocity, temperature and concentration fields were discussed thoroughly with the help of graphs obtained by using bvp5c MATLAB package. In view of many engineering applications we also computed the friction factor, heat and mass transfer coefficients and presented them in tables. Results indicate that an increase in thermal buoyancy parameter enhances the fluid velocity but suppresses the temperature. Deborah number have tendency to reduce the fluid velocity and mass transfer rate. It is also perceived that temperature ratio parameter has the propensity to enrich the fluid temperature

On the Geometry of the Nodal Lines of Eigenfunctions of the Two-Dimensional Torus

The width of a convex curve in the plane is the minimal distance between a pair of parallel supporting lines of the curve. In this paper we study the width of nodal lines of eigenfunctions of the Laplacian on the standard flat torus. We prove a variety of results on the width, some having stronger versions assuming a conjecture of Cilleruelo and Granville asserting a uniform bound for the number of lattice points on the circle lying in short arcs.Comment: 4 figures. Added some comments about total curvature and other detail

Parasitic nematodes and their management in major spices

Black pepper (Piper nigrum), cardamom (Elettaria cardamomum), ginger (Zingiber officinale), turmeric (Curcuma longa) and tree spices are the major spices cultivated in India. Several plant parasitic nematodes are reported on these spice crops and among them, root knot nematodes (Meloidogynespp.), burrowing nematodes (Radopholus similis and root lesion nematodes (Pratylenchus spp.) are the major nematode pests of economic importance. Plant parasitic nematodes are primary incitants of slow decline disease of black pepper. Root knot nematodes are a seious constraint to cardamom cultivation, especially in nurseries. In ginger and turmeric, all three of them cause significant damage. However, not much attention has been given to nematodes of tree spices. The major symptoms of nematode attack, the nature and extent of damage, their interaction with other soil borne microorganisms and various control measures are discussed. Considering the export oriented nature of these crops, emphasis has been given on integrated nematode management with minimum use of chemicals. &nbsp

Rhodobium gokarnense sp. nov., a novel phototrophic alphaproteobacterium from a saltern

A pink-pigmented, phototrophic, purple nonsulfur bacterium, strain JA173T, was isolated in pure culture from a saltern in Gokarna, India, in a medium containing 2 % (w/v) NaCl. Strain JA173T was a non-motile Gram-negative rod that multiplied by budding. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JA173T clusters with the class Alphaproteobacteria; highest sequence similarity (98 %) was to the type strain of Rhodobium orientis and 94 % similarity was observed to the 16S rRNA gene sequence of the type strain of Rhodobium marinum. However, DNA–DNA hybridization with R. orientis DSM 11290T revealed a relatedness value of only 35.1 % with strain JA173T. Strain JA173T contained lamellar internal membranes, bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Strain JA173T had an obligate requirement for NaCl (optimum growth at 2–6 %, w/v) and grew photoheterotrophically with a number of organic compounds as carbon source or electron donor. Photoautotrophic, chemoautotrophic and fermentative growth could not be demonstrated. Yeast extract was required for growth. Based on 16S rRNA gene sequence analysis, DNA–DNA hybridization data and morphological and physiological characteristics, strain JA173T is sufficiently different from other species of the genus Rhodobium to be recognized as a representative of a novel species, Rhodobium gokarnense sp. nov. The type strain is JA173T (=ATCC BAA-1215T=DSM 17935T=JCM 13532T)

Gravitational and electromagnetic fields of a charged tachyon

An axially symmetric exact solution of the Einstein-Maxwell equations is obtained and is interpreted to give the gravitational and electromagnetic fields of a charged tachyon. Switching off the charge parameter yields the solution for the uncharged tachyon which was earlier obtained by Vaidya. The null surfaces for the charged tachyon are discussed.Comment: 8 pages, LaTex, To appear in Pramana- J. Physic

Genome-wide analysis of core promoter elements from conserved human and mouse orthologous pairs

BACKGROUND: The canonical core promoter elements consist of the TATA box, initiator (Inr), downstream core promoter element (DPE), TFIIB recognition element (BRE) and the newly-discovered motif 10 element (MTE). The motifs for these core promoter elements are highly degenerate, which tends to lead to a high false discovery rate when attempting to detect them in promoter sequences. RESULTS: In this study, we have performed the first analysis of these core promoter elements in orthologous mouse and human promoters with experimentally-supported transcription start sites. We have identified these various elements using a combination of positional weight matrices (PWMs) and the degree of conservation of orthologous mouse and human sequences – a procedure that significantly reduces the false positive rate of motif discovery. Our analysis of 9,010 orthologous mouse-human promoter pairs revealed two combinations of three-way synergistic effects, TATA-Inr-MTE and BRE-Inr-MTE. The former has previously been putatively identified in human, but the latter represents a novel synergistic relationship. CONCLUSION: Our results demonstrate that DNA sequence conservation can greatly improve the identification of functional core promoter elements in the human genome. The data also underscores the importance of synergistic occurrence of two or more core promoter elements. Furthermore, the sequence data and results presented here can help build better computational models for predicting the transcription start sites in the promoter regions, which remains one of the most challenging problems

Evaluation of fungal bioagents for management of root-knot nematodes in ginger and turmeric fields

Ginger (Zingiber officinale Rosc.) and turmeric (Curcuma longa L.) are important herbaceousspices cultivated extensively in different states of India. Being vegetatively propagated, theyare challenged with several pests and diseases including plant parasitic nematodes. Root-knot nematode problem in these crops is currently managed with nematicides, cover cropsand organic amendments. Realizing the scope of biological control in these crops, a series ofexperiments were conducted at Indian Institute of Spices Research, Calicut, Kerala to screenand evaluate various fungal bioagents for control of root knot nematodes (Meloidogyneincognita) infesting ginger and turmeric under field conditions. Ten antagonistic fungi wereevaluated in different field experiments conducted in root-knot infested ginger and turmericfields at two locations. The most promising isolates that suppressed root knot nematodeswere Aspergillus nidulans (Is.10),  Fusarium oxysporum (Is.11), Paecilomyces lilacinus (Is.36),Trichoderma viride (Is. 25), Verticillium lecanii (Is.35) and Pochonia chlamydosporia (Is.32). Fromthese, three fungi viz.  F. oxysporum, T. viride and P. chlamydosporia were further tested inginger fields using two delivery systems, soil bed application and seed rhizome dippinggenerally applicable in dry shed treatment. The final results showed that  P. chlamydosporiasignificantly suppressed root knot nematodes in ginger and gave the maximum yieldirrespective of the mode of application. &nbsp