Theory of the Quantum Critical Fluctuations in Cuprates

The statistical mechanics of the time-reversal and inversion symmetry breaking order parameter, possibly observed in the pseudogap region of the phase diagram of the Cuprates, can be represented by the Ashkin-Teller model. We add kinetic energy and dissipation to the model for a quantum generalization and show that the correlations are determined by two sets of charges, one interacting locally in time and logarithmically in space and the other locally in space and logarithmically in time. The quantum critical fluctuations are derived and shown to be of the form postulated in 1989 to give the marginal fermi-liquid properties. The model solved and the methods devised are likely to be of interest also to other quantum phase transitions

A comprehensive study of electric, thermoelectric and thermal conductivities of Graphene with short range unitary and charged impurities

Motivated by the experimental measurement of electrical and hall conductivity, thermopower and Nernst effect, we calculate the longitudinal and transverse electrical and heat transport in graphene in the presence of unitary scatterers as well as charged impurities. The temperature and carrier density dependence in this system display a number of anomalous features that arise due to the relativistic nature of the low energy fermionic degrees of freedom. We derive the properties in detail including the effect of unitary and charged impurities self-consistently, and present tables giving the analytic expressions for all the transport properties in the limit of small and large temperature compared to the chemical potential and the scattering rates. We compare our results with the available experimental data. While the qualitative variations with temperature and density of carriers or chemical potential of all transport properties can be reproduced, we find that a given set of parameters of the impurities fits the Hall conductivity, Thermopower and the Nernst effect quantitatively but cannot fit the conductivity quantitatively. On the other hand a single set of parameters for scattering from Coulomb impurities fits conductivity, hall resistance and thermopower but not Nernst

A-OLSR: ANFIS based OLSR to select Multi point relay

The characteristics like dynamic topology, power consumption, mobility etc. may leads to affect the routing process of packet as it progresses from one node to another node. The energy of each node is very limited in MANET’s due to which it becomes an important parameter to be considered while selecting the route. The ‘Optimized Link State Routing Protocol’ (OLSR) does not consider node energy during Multipoint relay (MPR) selection process. This paper proposes an improvement of OLSR routing protocol named as A-OLSR protocol using node energy during its MPR process. The improvement is based on adaptive neuro fuzzy inference system (ANFIS). The network simulator NS2.35 is used for the simulation, random way point model for mobility and constant bit rate (CBR) for traffic process. The performance of proposed A-OLSR protocol is evaluated using the packet delivery ratio (PDR) and end to end delay metrices. The simulation results prove the superiority of the proposed protocol in terms of PDR

Variability of Low-ionization Broad Absorption Line Quasars Based on Multi-epoch Spectra from The Sloan Digital Sky Survey

We present absorption variability results for 134 bona fide \mgii\ broad absorption line (BAL) quasars at 0.46~$\lesssim z \lesssim$~2.3 covering days to $\sim$ 10 yr in the rest frame. We use multiple-epoch spectra from the Sloan Digital Sky Survey, which has delivered the largest such BAL-variability sample ever studied. \mgii-BAL identifications and related measurements are compiled and presented in a catalog. We find a remarkable time-dependent asymmetry in EW variation from the sample, such that weakening troughs outnumber strengthening troughs, the first report of such a phenomenon in BAL variability. Our investigations of the sample further reveal that (i) the frequency of BAL variability is significantly lower (typically by a factor of 2) than that from high-ionization BALQSO samples; (ii) \mgii\ BAL absorbers tend to have relatively high optical depths and small covering factors along our line of sight; (iii) there is no significant EW-variability correlation between \mgii\ troughs at different velocities in the same quasar; and (iv) the EW-variability correlation between \mgii\ and \aliii\ BALs is significantly stronger than that between \mgii\ and \civ\ BALs at the same velocities. These observational results can be explained by a combined transverse-motion/ionization-change scenario, where transverse motions likely dominate the strengthening BALs while ionization changes and/or other mechanisms dominate the weakening BALs.Comment: 24 pages, accepted for publication in ApJ

Inhibitory Effect of Some Plants of Western Ghats of Karnataka against Colletotrichum capsici

Anthracnose is a serious disease of chilli which results in major crop loss. Species of Colletotrichum are the causative agents of chilli anthracnose. In the present study, we investigated the inhibitory effect of a total of 50 extracts from 35 plants (belonging to 23 botanical families) of Western Ghats of Shivamogga district, Karnataka, India. The powdered plant materials were extracted using methanol. The methanol extracts were screened for antifungal activity by Poisoned food technique against Colletotrichum capsici isolated from anthracnose of chilli. All extracts were effective in inhibiting the growth of C. capsici but to a varied extent (16 to 74% inhibition). The mycelial growth of fungus was found to be reduced on poisoned plates when compared to control plate. Marked inhibitory efficacy was observed in case of leaf extract of Maesa indica (74.19%) followed by leaf extract of Pimenta dioica (70.96%). Least inhibition of the fungus was shown by leaf extract of Persea macrantha (16.13%). The extent of inhibition of the fungus by other extracts ranged between 20 to 70%. In conclusion, the plants selected in this study appear promising as natural antifungal agents. Further field studies are to be conducted to determine the possible application of these plants in the control of chilli anthracnose.Keywords: Western Ghats; Antifungal activity; Poisoned food technique; Colletotrichum capsici; Anthracnose of chill