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

A red alga Portieria hornemannii (Lyngb.) P. C. Silva 1987 (Gigartinales, Rhizophyllidaceae): A source of fragrance ingredient for perfume industry

898-902The application of marine plants such as seagrasses, seaweeds and mangroves for the production of perfumes are relatively less familiar to perfume industry. In the present study, a red seaweed Portieria hornemannii showing strong fragrance, collected from coral reefs of Gulf of Mannar, southeast coast of Tamil Nadu, India is proposed as a potential source of fragrance for perfumes. This species has a distinctive essence of perfume like flowery scents and can give off pleasant fragrance immediately after rubbing or rupture. Gas Chromatography and Mass Spectrometry analysis of methanol extracts of P. Hornemannii revealed the presence of chemical components N'-(3-Phenyl-2-Propenylidene)-2-(4-Chlorophenoxy) acethydrazide and 4, 5-Dichlorotricyclo [4.4.0.0(2,8)] dec-3-ene

Occurrence of a Scyphozoan jellyfish, Pelagia noctiluca (Forskål, 1775) bloom in the Gulf of Mannar Marine National Park, Southern India

161-164A massive Scyphozoan jellyfish bloom has been encountered in branching coral, Acropora dominated reef area in the southern part of Hare Island of Gulf of Mannar region, Tamil Nadu. The live specimens were identified as Pelagia noctiluca (Forskål, 1775), adding a new occurrence record to the Gulf of Mannar biodiversity. A sudden outburst of P. noctiluca bloom represented thousands of live specimens (> 100/m2 approximately) in the south side of Hare Island

Crustose coralline algae (Corallinales, Rhodophyta) diversity in the Gulf of Mannar marine national park, Southern India

241-245Rhodoliths are the prominent global reef builders, providing a hard calcium carbonate substrate to develop coral polyps and several marine algae. Studies on rhodoliths in the Gulf of Mannar Biosphere Reserve are very scarce. The present study investigated the various forms of crustose coralline algae inhabiting coral reefs in three islands of the Gulf of Mannar Biosphere Reserve. Eleven coralline algal genera with various morphological forms such as encrusting, fruticose, layered, lumpy, and warty were recorded. Further, the study infers that molecular assessment of the biodiversity of these rhodoliths is required to discriminate morphological similarities and confirm the species identity

Mass mortality of regular sea urchin Salmacis virgulata L. Agassiz and Desor, 1846 at Dhanushkodi, Southeast coast of Tamil Nadu, Gulf of Mannar, India

343-346Mass mortality of sea urchin, Salmacis virgulata scattered over the periphery of Dhanushkodi beach, was observed on February 13, 2019. More than 100 numbers of recently dead and dying specimens were found within a 10 m2 area on the sandy beach. Beach profiles indicated several hundreds of exoskeletons of previously dead S. virgulata were washed ashore and buried in sand and withering seagrass. The causative agent responsible for mass mortality of S. virgulata is yet to be discovered. However, observations on wave approach toward shore indicated possible evidence that it could be due to a combination of strong nearshore waves and currents. This observation raises a critical research concern to investigate etiology of S. virgulata for species conservation

Mass mortality of regular sea urchin Salmacis virgulata L. Agassiz and Desor, 1846 at Dhanushkodi, Southeast coast of Tamil Nadu, Gulf of Mannar, India

Mass mortality of sea urchin, Salmacis virgulata scattered over the periphery of Dhanushkodi beach, was observed on February 13, 2019. More than 100 numbers of recently dead and dying specimens were found within a 10 m2 area on the sandy beach. Beach profiles indicated several hundreds of exoskeletons of previously dead S. virgulata were washed ashore and buried in sand and withering seagrass. The causative agent responsible for mass mortality of S. virgulata is yet to be discovered. However, observations on wave approach toward shore indicated possible evidence that it could be due to a combination of strong nearshore waves and currents. This observation raises a critical research concern to investigate etiology of S. virgulata for species conservation

Antihyperlipidemic activity of Chloroxylon swietenia in triton WR1339 induced hyperlipidemia

Background: Medicinal herbs are beneficial and effective either in the management and prevention of several metabolic disorders, associated with hyperlipidemia, hypertension and insulin resistance which increases the cardio-metabolic risk and demands for the life time therapy. Current allopathic medicines are expensive and reported with several adverse effects and hence, finding of a suitable herbal medicine for hyperlipidemic disorders is very important.Methods: Thirty albino rats weighing 200-230g were randomly divided into 5 groups were rendered hyperlipidemia with a single dose of triton WR 1339. Normal control, positive control, standard, aqueous and ethanolic extract groups were treated with tween-80, tween-80, atorvastatin, aqueous and ethanolic extracts of Chloroxylon swietenia respectively for seven days. At the end of the study, blood was collected for estimation of the lipid profile.Results: Both the aqueous and ethanolic extract groups significantly reduced the TG and VLDL levels.Conclusions: The extracts exhibited remarkable activity on one or either parameter of the lipid profile. It could be due to the presence of alkaloids, steroids, flavonoids, coumarins and phenols in the extracts

Experimental observation of the amplitude death effect in two coupled nonlinear oscillators

The amplitude death phenomenon has been experimentally observed with a pair of thermo-optical oscillators linearly coupled by heat transfer. A parametric analysis has been done and compared with numerical simulations of a time delayed model. The role of the coupling strength is also discussed from experimental and numerical results

Recent development of self-interaction-free time-dependent density-functional theory for nonperturbative treatment of atomic and molecular multiphoton processes in intense laser fields

This is the published version, also available here: http://dx.doi.org/10.1063/1.1904587.In this paper, we present a short account of some recent developments of self-interaction-free density-functional theory(DFT) and time-dependent density-functional theory (TDDFT) for accurate and efficient treatment of the electronic structure, and time-dependent quantum dynamics of many-electron atomic and molecular systems. The conventional DFT calculations using approximate and explicit exchange-correlation energy functional contain spurious self-interaction energy and improper long-range asymptotic potential, preventing reliable treatment of the excited, resonance, and continuum states. We survey some recent developments of DFT/TDDFT with optimized effective potential (OEP) and self-interaction correction (SIC) for both atomic and molecular systems for overcoming some of the above mentioned difficulties. These DFT (TDDFT)/OEP-SIC approaches allow the use of orbital-independent single-particle local potential which is self-interaction free. In addition we discuss several numerical techniques recently developed for efficient and high-precision treatment of the self-interaction-free DFT/TDDFT equations. The usefulness of these procedures is illustrated by a few case studies of atomic, molecular, and condensed matter processes of current interests, including (a) autoionizing resonances, (b) relativistic OEP-SIC treatment of atomic structure (Z=2–106), (c) shell-filling electronic structure in quantum dots, (d) atomic and molecular processes in intense laser fields, including multiphoton ionization, and very-high-order harmonic generation, etc. For the time-dependent processes, an alternative Floquet formulation of TDDFT is introduced for time-independent treatment of multiphoton processes in intense periodic or quasiperiodic fields. We conclude this paper with some open questions and perspectives of TDDFT

Relaxation of Surface Profiles by Evaporation Dynamics

We present simulations of the relaxation towards equilibrium of one dimensional steps and sinusoidal grooves imprinted on a surface below its roughening transition. We use a generalization of the hypercube stacking model of Forrest and Tang, that allows for temperature dependent next-nearest-neighbor interactions. For the step geometry the results at T=0 agree well with the t^(1/4) prediction of continuum theory for the spreading of the step. In the case of periodic profiles we modify the mobility for the tips of the profile and find the approximate solution of the resulting free boundary problem to be in reasonable agreement with the T=0 simulations.Comment: 6 pages, Revtex, 5 Postscript figures, to appear in PRB 15, October 199