Interspecific Hybrid Developed in Epidendrum Orchid from the Cross E. radicans Pav. Ex. Lindl. X E. xanthinum Lindl.

An interspecific Epidendrum hybrid was developed using E. radicans (known as 'fire star orchid', 'ground-rooted orchid') as female parent and E. xanthinum known as 'yellow orchid' as male parent. The selected line (NRCO Epidendrum cross/2005-01) was characterized for morphological and floral traits. Flower size (3.5 cm x 3.4 cm) of selected line was bigger than both parents, with bright saffron-orange colour (RHS 44A). Dorsal sepal size (1.8 cm x 0.6 cm), lateral sepal size (1.9 cm x 0.7 cm), petal size (1.8 cm x 0.6 cm), lip size (2.3 cm x 2 cm) and column size (1.1 cm x 0.2 cm) were bigger than in parents. Shape and fimbriated side lobes of lip with deep cleft of anterior margins was similar to the male parent (E. xanthinum), except colour. The F1progeny of 'NRCO-Epidendrum cross/2005-01' flowered with different red-orange to yellow shades is categorized broadly into three types: Red-orange, Orangeyellow and Yellow. Epidendrums are popularly known as 'Crucifix orchid' and 'Poor man's orchid', have a long flowering period with 2-3 flowerings in a year, and are easy to multiply. These attributes are ideal for popularizing this plant in India as a potted plant as well garden plant

Helical edge states in multiple topological mass domains

The two-dimensional topological insulating phase has been experimentally discovered in HgTe quantum wells (QWs). The low-energy physics of two-dimensional topological insulators (TIs) is described by the Bernevig-Hughes-Zhang (BHZ) model, where the realization of a topological or a normal insulating phase depends on the Dirac mass being negative or positive, respectively. We solve the BHZ model for a mass domain configuration, analyzing the effects on the edge modes of a finite Dirac mass in the normal insulating region (soft-wall boundary condition). We show that at a boundary between a TI and a normal insulator (NI), the Dirac point of the edge states appearing at the interface strongly depends on the ratio between the Dirac masses in the two regions. We also consider the case of multiple boundaries such as NI/TI/NI, TI/NI/TI and NI/TI/NI/TI.Comment: 11 pages, 15 figure

Helical edge states in multiple topological mass domains

The two-dimensional topological insulating phase has been experimentally discovered in HgTe quantum wells (QWs). The low-energy physics of two-dimensional topological insulators (TIs) is described by the Bernevig-Hughes-Zhang (BHZ) model, where the realization of a topological or a normal insulating phase depends on the Dirac mass being negative or positive, respectively. We solve the BHZ model for a mass domain configuration, analyzing the effects on the edge modes of a finite Dirac mass in the normal insulating region (soft-wall boundary condition). We show that at a boundary between a TI and a normal insulator (NI), the Dirac point of the edge states appearing at the interface strongly depends on the ratio between the Dirac masses in the two regions. We also consider the case of multiple boundaries such as NI/TI/NI, TI/NI/TI and NI/TI/NI/TI.Comment: 11 pages, 15 figure

Coexistence of magnetism and superconductivity in a t-J bilayer

We investigate coexistence of antiferromagnetic and superconducting correlations in bilayered materials using a two-dimensional t-J model with couplings across the layers using variational Monte Carlo calculations. It is found that the underdoped regime supports a coexisting phase, beyond which the (d-wave) superconducting state becomes stable. Further, the effects of interplanar coupling parameters on the magnetic and superconducting correlations as a function of hole doping are studied in details. The magnetic correlations are found to diminish with increasing interplanar hopping away from half filling, while the exchange across the layers strengthens interplanar antiferromagnetic correlations both at and away from half filling. The superconducting correlations show more interesting features where larger interplanar hopping considerably reduces planar correlations at optimal doping, while an opposite behaviour, i.e. stabilisation of the superconducting state is realised in the overdoped regime, with the interplanar exchange all the while playing a dormant role.Comment: 8 pages, 9 figures, RevTex4, Submitted to Phys. Rev.

Autoimmune hypophysitis presenting as solid-cystic mass managed conservatively

Background: Autoimmune hypophysitis (AH) is a rare inflammatory condition of the pituitary gland and usually affects women of childbearing age. It commonly leads to pituitary dysfunction. Moreover, pituitary enlargement may lead to compressive symptoms, which necessitates urgent surgical decompression. Resection of the pituitary gland causes iatrogenic hypopituitarism which requires lifelong hormonal supplementation. With an increasing number of suspected cases of pituitary diseases, there has been a paradigm shift in the management by conservative measures, especially, when surgery is not urgently needed. Case Report: We report a case of AH in a premenopausal woman presenting with headache. MRI revealed a solid-cystic mass involving the anterior lobe of the pituitary gland. The infundibulum was also thickened and enhancing; however, it was still in the midline. Ancillary MRI findings and hormonal profile were favouring the diagnosis of AH over pituitary neoplasm. The patient was managed conservatively with high doses of glucocorticoids, which resulted in prompt resolution of the lesion. During subsequent follow-up over 6 years, there was no recurrence and partial restoration of the pituitary function was seen. This case is interesting due to an unusual MRI appearance of AH, presenting as a solid-cystic mass. Moreover, disease resolution with conservative treatment strengthens the approach to limit surgery to those patients with compressive symptoms or uncertain diagnosis. Conclusions: AH should be included in the differential diagnosis of solid-cystic pituitary masses along with clinical correlation, which includes early involvement of ACTH and TSH and a relatively rapid development of hypopituitarism. In uncertain cases or with lack of compressive symptoms, a trial of steroids is worthwhile

Multi-wavelength polarimetric study towards the open cluster NGC 1893

We present multi-wavelength linear polarimetric observations for 44 stars of the NGC 1893 young open cluster region along with V-band polarimetric observations of stars of other four open clusters located between l ~160 to ~175 degree. We found evidence for the presence of two dust layers located at a distance of ~170 pc and ~360 pc. The dust layers produce a polarization Pv ~2.2%. It is evident from the clusters studied in the present work that, in the Galactic longitude range l ~160 to 175 degree and within the Galactic plane (|b| < 2 degree), the polarization angles remain almost constant, with a mean ~163 degree and a dispersion of 6 degree. The small dispersion in polarization angle could be due to the presence of uniform dust layer beyond 1 kpc. Present observations reveal that in case of NGC 1893, the foreground two dust layers, in addition to the intracluster medium, seems to be responsible for the polarization effects. It is also found that towards the direction of NGC 1893, the dust layer that exists between 2-3 kpc has a negligible contribution towards the total observed polarization. The weighted mean for percentage of polarization (Pmax) and the wavelength at maximum polarization ({\lambda}max) are found to be 2.59 \pm 0.02% and 0.55 \pm 0.01 \mum respectively. The estimated mean value of {\lambda}max indicates that the average size of the dust grains within the cluster is similar to that in the general interstellar medium. The spatial variation of the polarization is found to decrease towards the outer region of the cluster. In the present work, we support the notion, as already has been shown in previous studies, that polarimetry, in combination with (U-B)/(B-V) colour-colour diagram, is a useful tool for identifying non-members in a cluster.Comment: 36 pages, 12 figures, 10 tables, accepted for the publication in MNRA

Theoretical studies on hydrogen bonding in π-electron systems: a note on the structural features of diacetylene-hydrogen fluoride complexes

Ab initio supermolecular SCF calculations at the STO-3G level are reported for the diacetylene-hydrogen fluoride complexes. The reverse σ-complex is predicted to have somewhat higher stability and H-bond strength than the π-complexes

Transcription of the results of quantum chemical calculations in terms of the classical notion of molecular structures: the cases of some small carbonyls in the ground and excited states

Quantum chemical valence parameters of several carbonyl molecules in the ground and excited states are calculated by invoking the INDO-orthogonal gradient method in an MC-SCF framework. These parameters are then used to construct state-specific structural descriptions of these molecules in terms of superposition of several canonical structures. Photochemical reactivities of some of these molecules are sought to be explained on the basis of the picture that emerges