3,849 research outputs found

    Occurence of hammer oyster, Malleus albus near Nachikuppam, Chennai

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    The hammer oyster, Malleus albus is placed under Class Bivalvia, Subclass Pteriomorphia, Order Pterioida, Superfamily Pteriacea, Family Malleidae. The oyster is locally called suti ali. These oysters (Fig. 1 a and b) were caught by fishermen from Nachikuppam, 1-2 km off Chennai using Nakkuvalai, a bottom set gillnet, at a depth of 5-7 fathoms. The maximum and minimum shell length was 156 mm and 77 mm and the average length and weight were 117 mm and 29 g respectively

    Supersolid and solitonic phases in one-dimensional Extended Bose-Hubbard model

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    We report our findings on quantum phase transitions in cold bosonic atoms in a one dimensional optical lattice using the finite size density matrix renormalization group method in the framework of the extended Bose-Hubbard model. We consider wide ranges of values for the filling factors and the nearest neighbor interactions. At commensurate fillings, we obtain two different types of charge density wave phases and a Mott insulator phase. However, departure from commensurate fillings yield the exotic supersolid phase where both the crystalline and the superfluid orders coexist. In addition, we obtain signatures for solitary waves and also superfluidity.Comment: 7 pages, 11 figure

    First record of the chimaeroid, Rhinochimaera atlantica at Kasimedu Fisheries Harbour, Chennai

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    Bumper landings of skipjack tuna, Katsuwonus pelamis was observed at Visakhapatnam Fishing Harbour on 28th October 2011, wherein about 42 t were landed by hooks and line

    26-G needle-assisted sutureless glueless intrascleral haptic fixation for secondary ciliary sulcus implantation of three-piece polymethylmethacrylate intraocular lens during penetrating keratoplasty

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    AbstractAfter tenotomy adjoining 3 o'clock and 9 o'clock limbus, 3-mm-wide partial-thickness scleral tunnels are created at these two diametrically opposite points 3 mm from the limbus such that they reach up to a distance of 1.5 mm from the limbus. Two ab externo sclerotomies are created using 26-G needles on the bed of these partial-thickness scleral tunnels. Precaution is taken to ensure that the positions of the sclerotomies are diagonally opposite each other. A scleral niche is made using a 26-G needle to accommodate the intraocular lens (IOL) haptic later. A 7.5-mm trephine is used to excise the corneal button, and anterior vitrectomy is performed. The haptic of a three-piece polymethylmethacrylate IOL is docked in a bent 26-G needle. It is then pulled out under the partial-thickness scleral tunnel and placed securely in the scleral niche opposite to the haptic. An 8-mm donor corneal button is sutured in place using 16 equidistantly placed 10-0 nylon interrupted sutures

    On instantons as Kaluza-Klein modes of M5-branes

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    Instantons and W-bosons in 5d maximally supersymmetric Yang-Mills theory arise from a circle compactification of the 6d (2,0) theory as Kaluza-Klein modes and winding self-dual strings, respectively. We study an index which counts BPS instantons with electric charges in Coulomb and symmetric phases. We first prove the existence of unique threshold bound state of (noncommutative) U(1) instantons for any instanton number, and also show that charged instantons in the Coulomb phase correctly give the degeneracy of SU(2) self-dual strings. By studying SU(N) self-dual strings in the Coulomb phase, we find novel momentum-carrying degrees on the worldsheet. The total number of these degrees equals the anomaly coefficient of SU(N) (2,0) theory. We finally show that our index can be used to study the symmetric phase of this theory, and provide an interpretation as the superconformal index of the sigma model on instanton moduli space.Comment: 54 pages, 2 figures. v2: references added, figure improved, added comments on self-dual string anomaly, added new materials on the symmetric phase index, other minor correction

    The Conformal Anomaly of M5-Branes

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    We show that the conformal anomaly for N M5-branes grows like N3N^3. The method we employ relates Coulomb branch interactions in six dimensions to interactions in four dimensions using supersymmetry. This leads to a relation between the six-dimensional conformal anomaly and the conformal anomaly of N=4 Yang-Mills. Along the way, we determine the structure of the four derivative interactions for the toroidally compactified (2,0) theory, while encountering interesting novelties in the structure of the six derivative interactions.Comment: 38 pages, LaTeX; references adde

    A program for a problem free Cosmology within a framework of a rich class of scalar tensor theories

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    A search for a problem free cosmology within the framework of an effective non - minimally coupled scalar tensor theory is suggested. With appropriate choice of couplings in variants of a Lee - Wick model [as also in a model supporting Q - ball solutions], non topological solutions [NTS's], varying in size upto 10 kpc to 1 Mpc can exist. We explore the properties of a ``toy'' Milne model containing a distribution of NTS domains. The interior of these domains would be regions where effective gravitational effects would be indistinguishable from those expected in standard Einstein theory. For a large class of non - minimal coupling terms and the scalar effective potential, the effective cosmological constant identically vanishes. The model passes classical cosmological tests and we describe reasons to expect it to fare well as regards nucleosynthesis and structure formation.Comment: 20 pages, Plain Tex, references added and expanded the previous version of article, 2 figures available from [email protected]

    Maladaptive striatal plasticity and abnormal reward-learning in cervical dystonia

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    In monogenetic generalized forms of dystonia, in vitro neurophysiological recordings have demonstrated direct evidence for abnormal plasticity at the level of the cortico‐striatal synapse. It is unclear whether similar abnormalities contribute to the pathophysiology of cervical dystonia, the most common type of focal dystonia. We investigated whether abnormal cortico‐striatal synaptic plasticity contributes to abnormal reward‐learning behavior in patients with focal dystonia. Forty patients and 40 controls performed a reward gain and loss avoidance reversal learning task. Participant's behavior was fitted to a computational model of the basal ganglia incorporating detailed cortico‐striatal synaptic learning rules. Model comparisons were performed to assess the ability of four hypothesized receptor specific abnormalities of cortico‐striatal long‐term potentiation (LTP) and long‐term depression (LTD): increased or decreased D1:LTP/LTD and increased or decreased D2: LTP/LTD to explain abnormal behavior in patients. Patients were selectively impaired in the post‐reversal phase of the reward task. Individual learning rates in the reward reversal task correlated with the severity of the patient's motor symptoms. A model of the striatum with decreased D2:LTP/ LTD best explained the patient's behavior, suggesting excessive D2 cortico‐striatal synaptic depotentiation could underpin biased reward‐learning in patients with cervical dystonia. Reversal learning impairment in cervical dystonia may be a behavioral correlate of D2‐specific abnormalities in cortico‐striatal synaptic plasticity. Reinforcement learning tasks with computational modeling could allow the identification of molecular targets for novel treatments based on their ability to restore normal reward‐learning behavior in these patients
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