Purification of large bicolorable graph states

We describe novel purification protocols for bicolorable graph states. The protocols scale efficiently for large graph states. We introduce a method of analysis that allows us to derive simple recursion relations characterizing their behavior as well as analytical expressions for their thresholds and fixed point behavior. We introduce two purification protocols with high threshold. They can, for graph degree four, tolerate 1% (3%) gate error or 20% (30%) local error.Comment: 12 pages, 5 figures, revtex; typos and clarifications adde

Effect of mass asymmetry on the mass dependence of balance energy

We demonstrate the role of the mass asymmetry on the balance energy (Ebal) by studying asymmetric reactions throughout the periodic table and over entire colliding geometry. Our results, which are almost independent of the system size and as well as of the colliding geometries indicate a sizeable effect of the asymmetry of the reaction on the balance energy.Comment: Journal of Physics - Conference Series - Online end of March (2011

Bulk Viscosity of Magnetized Neutron Star Matter

We study the effect of magnetic field on the bulk viscosity of nuclear matter in neutron stars. We employ the framework of relativistic mean field theory to observe the dense nuclear matter in neutron stars. The effects are first studied for the case when the magnetic field does not exceed the critical value to confine the electrons to the lowest Landau levels. We then consider the case of intense magnetic field to evaluate viscosity for the URCA processes and show that the inequality $p_{F}(e)+p_{F}(p)\geq p_{F}(n)$ is no longer required to be satisfied for the URCA processes to proceed.Comment: Latex 2e file with four postscripts figure

Further evidence for intra-night optical variability of radio-quiet quasars

Although well established for BL Lac objects and radio-loud quasars, the occurrence of intra-night optical variability (INOV) in radio-quiet quasars is still debated, primarily since only a handful of INOV events with good statistical significance, albeit small amplitude, have been reported so far. This has motivated us to continue intra-night optical monitoring of bona-fide radio-quiet quasars (RQQs). Here we present the results for a sample of 11 RQQs monitored by us on 19 nights. On 5 of these nights a given RQQ was monitored simultaneously from two well separated observatories. In all, two clear cases and two probable case of INOV were detected. From these data, we estimate an INOV duty cycle of $\sim$8% for RQQs which would increase to 19% if the `probable variable' cases are also included. Such comparatively small INOV duty cycles for RQQs, together with the small INOV amplitudes ($\sim$1%), are in accord with the previously deduced characteristics of this phenomenon.Comment: 15 Pages, 4 Tables, 24 Figures; Accepted in BAS

Enhanced flux pinning in YBa2Cu3O7-d films by nano-scaled substrate surface roughness

Nano-scaled substrate surface roughness is shown to strongly influence the critical current density Jc in YBCO films made by pulse-laser-deposition on the crystalline LaAlO3 substrates consisting of two separate twin-free and twin-rich regions. The nano-scaled corrugated surface was created in the twin-rich region during the deposition process. Using magneto-optical imaging techniques coupled with optical and atomic force microscopy, we observed an enhanced flux pinning in the YBCO films in the twin-rich region, resulted in \~30% increase in Jc, which was unambiguously confirmed by the direct transport measurement.Comment: 16 pages, 3 figures, accepted by Applied Physics Letter

Contagion Risk and Network Design

Individuals derive bene ts from their connections, but these may, at the same time, transmit external threats. Individuals therefore invest in security to protect themselves. However, the incentives to invest in security depend on their network exposures. We study the problem of designing a network that provides the right individual incentives. Motivated by cybersecurity, we rst study the situation where the threat to the network comes from an intelligent adversary. We show that, by choosing the right topology, the designer can bound the welfare costs of decentralized protection. Both over-investment as well as under-investment can occur depending on the costs of security. At low costs, over-protection is important: this is addressed by discon- necting the network into two unequal components and sacri cing some nodes. At high costs, under-protection becomes salient: it is addressed by disconnecting the network into equal components. Motivated by epidemiology, we then turn to the study of random attacks. The over-protection problem is no longer present, whereas under-protection problems is mitigated in a diametrically opposite way: namely, by creating dense networks that expose the individuals to the risk of contagion

Size and morphology of sella and volumetric evaluation of pituitary gland: a radiological survey

Background: Sella turcica is an important anatomical structure in the middle cranial fossa. It’s size follows the size of pituitary gland. The present study aimed to evaluate the size and morphology of sella and pituitary gland in the same patients without known hormonal or pituitary pathology.Methods: In this cross-sectional observational study three hundred patients underwent lateral x-ray of skull for sella turcica measurements and MRI brain for pituitary gland measurements.Results: We observed normal shape of sella (round or oval) in 66.7% of the study participants. Maximum mean anterior-posterior (AP) dimension was seen in the age group of 41 to 50 years (1.24±0.19 cm), while maximum length (0.87±0.12 cm), depth (0.87±0.21 cm) and volume (0.49±0.21 cu cm) was observed in the age group of 51 to 60 years. Similarly, CC dimension was observed to be maximum in the age group 41 to 50 years (5.9±0.51 mm). Study participants of age group more than 60 years had the maximum mean transverse dimension (12.73±0.29 mm) and the pituitary volume on MRI was observed to be maximum for the age group 51 to 60 years (398.45±61.24 cu mm).Conclusions: In our sample of 300 patients, sella turcica was normally shaped in 66.7%. Various dimensions of sella turcica and pituitary gland increased significantly till 50 to 60 years of of age, after which they decreased

Establishment of an efficient protocol for micropropagation of stem explants of Tylophora indica, an important medicinal plant

An efficient reproducible protocol has been developed for in vitro propagation of endangered medicinal plant (Tylophora indica). The concentration of plant growth regulators and explant types exhibited discrete roles in the efficiency of plant regeneration. Stem explants cultured on 8.8 μM 6- benzylaminopurine (BAP) resulted in formation of nodular meristemoids, which developed into green leafy shoots 6 to 8 weeks after culturing on the same medium. 29.4 μM α-naphthalene acetic acid (NAA) and 4.65 μM kinetin (Kn) induced green solid callus within 7 to 8 days of culturing. Callus thus formed, revealed the presence of cells of variable shapes and sizes together with xylogenesis. Calli when subcultured on MS medium supplemented with 8.8 μM BAP developed adventitious shoots, however, initially, few shoots were formed but the number increased further on subsequent subculturing. Microshoots thus formed, were cultured on indole 3-butyric acid (IBA) and half strength basal MS media for induction of roots. Regenerated plantlets with healthy shoots and roots were acclimatized in moist cotton followed by their hardening in soil : vermicompost potting mixture with 90% survival rate.Key words: Tylophora indica, organogenesis, 6-benzylaminopurine, α-naphthalene acetic acid, indole 3- butyric acid

Performance of a Hazardous Waste and Sanitary Landfill Subjected to Loma Prieta Earthquake

Loma Prieta Earthquake of October 17, 1989 caused severe damages in the San Francisco Bay Area. Field measurements made during the earthquake and analyses performed to date indicate that bedrock accelerations were amplified to 2 to 3 times in propagating through deep cohesive deposits. In view of this, the performance of a hazardous waste and sanitary landfill subjected to Loma Prieta Earthquake and founded on deep cohesive deposits was evaluated. Analyses indicate that the peak accelerations at the base of the refuse are slightly amplified in propagating through the refuse thicknesses of up to about 50 feet. For higher refuse thicknesses, the peak base acceleration attenuates significantly. Slope stability and liquefaction analyses were also performed using these accelerations. The results indicate some but small potential for plastic deformation. These results were supported by the post-earthquake field inspection and the field data collected during the earthquake