Porella perrottetiana (Porellaceae, Marchantiophyta) a species from the Western Ghats of Kerala

Porella perrottetiana Trev. is reported from the Western Ghats of Kerala. This is the first record of this species from Kerala

Fissidens linearis (Fissidentaceae: Bryophyta) a new record for India

Abstract Fissidens linearis var. obscurirete, is reported as a new record of occurrence to India from the Western Ghats of Kerala

Observation of a Modulational Instability in Bose-Einstein condensates

We observe the breakup dynamics of an elongated cloud of condensed $^{85}$Rb atoms placed in an optical waveguide. The number of localized spatial components observed in the breakup is compared with the number of solitons predicted by a plane-wave stability analysis of the nonpolynomial nonlinear Schr\"odinger equation, an effective one-dimensional approximation of the Gross-Pitaevskii equation for cigar-shaped condensates. It is shown that the numbers predicted from the fastest growing sidebands are consistent with the experimental data, suggesting that modulational instability is the key underlying physical mechanism driving the breakup.Comment: 6 pages, 5 figure

A synopsis of the family Pottiaceae (Bryophyta) of Kerala, India

The Potttiaceae are one of the dominant acrocarpic moss family of India with 26 genera and 130 species. The present paper is a synopsis of the family Pottiaceae in Kerala State. Here we report 18 species distributed among 13 genera such as Anoectangium aestivum, A. bicolor, Barbula tenuirostris, B. indica, Hyophila involuta, H. nymaniana, Hymenostylium recurvirostrum, Hy-menostomum edentulum, Indopottia zanderii, Oxystegus cylindricus, Pottia bry-oides, Scopelophila cataractae, S. ligulata, Syntrichia fragilis, T. muralis, Tor-tella tortuosa, Trichostomum wayanadense and T. crispulum. Among these one species viz., Pottia bryoides is a new record for India. Scopelophila ligulata is widely known as “copper moss” but this species was not recorded yet from Pen-insular India. This report is then new to Peninsular India. Two species viz; Bar-bula tenuirostris Brid. and Syntrichia fragilis (Tayl.) Ochyra. are new records for Kerala and Indopottia zanderii is endemic to Western Ghats

Contribution to the bryophyte flora of India

The bryophyte flora of the Silent Valley National Park is catalogued. The catalogue consists of 148 taxa (109 mosses, 36 liverworts, 3 hornworts), of which nine species viz., Chrysocladium flammeum (Mitt.) M.Fleisch., Gymnostomum calcareum Nees & Hornsch., Glossadelphus bilobatus (Dix.) Broth., Hypnum flaccens Besch., Notoscyphus paroicus Schiffn., Macromitrium turgidum Dix., Calyptothecium pinnatum Nog., Brotherella amblystegia (Mitt.) Broth. and Wijkia deflexifolia (Ren. & Card.) Crum. are newly reported for Peninsular India. Another four species viz., Lejeunea cavifolia (Ehrh.) Lindb., Radula obscura Mitt., Radula meyeri Steph. and Barbella turgida Nog. are new record of occurrence for Kerala State. Trichostelium stigmosum (Manju et al., 2012) and Aerobryopsis wallichii (Brid.) Fleisch. (Prajitha et al., in press), has been reported as new records for India from Silent Valley

Non-destructive shadowgraph imaging of ultracold atoms

An imaging system is presented that is capable of far-detuned non-destructive imaging of a Bose-Einstein condensate with the signal proportional to the second spatial derivative of the density. Whilst demonstrated with application to $^{85}\text{Rb}$, the technique generalizes to other atomic species and is shown to be capable of a signal to noise of ${\sim}25$ at $1$GHz detuning with $100$ in-trap images showing no observable heating or atom loss. The technique is also applied to the observation of individual trajectories of stochastic dynamics inaccessible to single shot imaging. Coupled with a fast optical phase lock loop, the system is capable of dynamically switching to resonant absorption imaging during the experiment.Comment: 4 pages, 5 figure

On the identity of Riccia fluitans (Ricciaceae: Marchantiophyta) in India

The status of the species Riccia fluitans in India is discussed in detail. Most of the Indian specimens described under R. fluitans are Riccia stricta. Specimens collected from different parts of India were compared with specimens from BM. Photographs are provided for easy identification

A quantum sensor: simultaneous precision gravimetry and magnetic gradiometry with a Bose-Einstein condensate

A Bose-Einstein condensate is used as an atomic source for a high precision sensor. A $5\times 10^6$ atom F=1 spinor condensate of $^{87}$Rb is released into free fall for up to $750$ms and probed with a Mach-Zehnder atom interferometer based on Bragg transitions. The Bragg interferometer simultaneously addresses the three magnetic states, $\left| m_f=1,0,-1 \right\rangle$, facilitating a simultaneous measurement of the acceleration due to gravity with an asymptotic precision of $2.1\times 10^{-9}$$\Delta$g/g and the magnetic field gradient to a precision $8$pT/m