Exactly solvable Kitaev model in three dimensions

We introduce a spin-1/2 model in three dimensions which is a generalization of the well-known Kitaev model on a honeycomb lattice. Following Kitaev, we solve the model exactly by mapping it to a theory of non-interacting fermions in the background of a static Z_2 gauge field. The phase diagram consists of a gapped phase and a gapless one, similar to the two-dimensional case. Interestingly, unlike in the two-dimensional model, in the gapless phase the gap vanishes on a contour in the k space. Furthermore, we show that the flux excitations of the gauge field, due to some local constraints, form loop like structures; such loops exist on a lattice formed by the plaquettes in the original lattice and is topologically equivalent to the pyrochlore lattice. Finally, we derive a low-energy effective Hamiltonian that can be used to study the properties of the excitations in the gapped phase.Comment: 9 pages, 7 figures; published version; a new section and more references adde

Incidence and Molecular Typing of Vibrio parahaemolyticus from Tiger Shrimp Culture Environments along the Southwest Coast of India

Vibrio parahaemolyticus is one of the most prevalent food-borne pathogens along the southwest coast of India, where marine foods are frequently consumed. Shrimp (Penaeus monodon) and environmental samples were collected from aquaculture farms located in and around Cochin. Confirmation of the biochemically identified strains with species-specific toxR gene and detection of virulent genes viz., tdh and trh was performed by polymerase chain reaction (PCR). The phenotypic markers for the presence of tdh and trh genes were assayed by Kanagawa phenomenon and urease activity, respectively. Protease activity was examined to identify other potential virulence factors. After phenotypic characterization of bacterial strains fingerprinting of genomic DNA was carried by various typing methods, viz., random amplified polymorphic DNA (RAPD), enterobacterial repetitive intergenic consensus sequence (ERIC), repetitive extragenic palindromic sequence (REP), and ribosomal gene spacer sequence (RS) PCR methods to assess the genetic diversity within the isolates. Eighteen percent of the samples were found positive for the incidence of V. parahaemolyticus by biochemical protocols and toxR (368 bp) targeted PCR. PCR analyses revealed 1% of the samples positive for tdh (269 bp) and trh (500 bp) gene. RAPD analysis revealed clustering of toxigenic strains into a single group. Cluster analysis revealed the conglomeration of isolates into two, five, and seven major groups using RS, ERIC, and REP PCR methods, respectively. RS PCR generated fewer amplified bands compared to REP and ERIC PCR methods, thus giving scope for higher discrimination. Moreover, RS PCR patterns were more discernible visually from other patterns, suggesting RS PCR as a considerably practical method for routine use

AYURVEDIC MANAGEMENT OF PLAQUE PSORIASIS- A CASE STUDY

Psoriasis is a chronic, multisystem inflammatory disease with predominantly skin and joint involvement. In Ayurveda all skin diseases are described under the umbrella of Kushtha. Ayurvedic system of medicine is giving good results in management of Psoriasis. Repeated Samshodhana (purificatory therapies) along with Samshamana (palliative therapies) is the main line of treatment if skin diseases in Ayurveda. Three assessments were taken before and after treatment on scoring of Dermatology Life Quality Index (DLQI), Psoriasis Disability Index (PDI) and PASI score. Score of the patient was 63.3% before treatment and 13.3% after treatment and 3.3% after follow up on Dermatology Life Quality Index (DLQI), 44.4% before treatment and 15.5% after treatment and 5.3% after follow up on Psoriasis Disability Index (PDI) and 24.5% before treatment, 5.1% after treatment and 1.2% after follow up in PASI (Psoriasis Area and Severity Index).  This case study wants to substantiate the effectiveness of Ayurvedic treatment in the management of Plaque psoriasis