Search for a Permanent Electric Dipole Moment of \u3csup\u3e225\u3c/sup\u3eRa

The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate the violation of discrete symmetries of Time reversal (T) or combined application of Charge (C) and Parity (P) symmetry violation through the CPT theorem. The diamagnetic 225Ra atom with nuclear spin I=1/2 is a favorable candidate for an EDM search. Experimental sensitivity to its EDM is enhanced due to its high atomic mass and the increased Schiff moment of its octupole deformed nucleus. An experimental setup is developed where laser cooled neutral radium atoms are collected in a magneto-optical trap (MOT). The collected atoms are transported 1 meter with a far off-resonant optical dipole trap (ODT) and then the atoms are transferred to a second standing-wave ODT in an experimental chamber. The atoms are then optically polarized and allowed to Larmor precess in parallel and antiparallel electric and magnetic fields. The difference between the Larmor precession frequency for parallel and antiparallel fields is experimentally determined to measure the EDM. This thesis is about the first measurement of the EDM of the 225Ra atom where an upper limit of |d(225Ra)|\u3c5.0*10-22 e cm (95\% confidence) is reached

Larvicidal efficacy of Toddalia asiatica (Linn.) Lam against two mosquito vectors Aedes aegypti and Culex quinquefasciatus

The hexane, acetone and methanol extracts of mature fruits and leaves from Toddalia asiatica was investigated to establish its bio-control potentiality under laboratory condition against fourth instars larvae of Dengue vector, Aedes aegypti and Filarial vector, Culex quinquefasciatus. Hexane extract of fruits of T. asiatica showed highest larvicidal activity against both mosquito vector. LC50 value of hexane, acetone and methanol extracts of fruits against A. aegypti were 37.23, 50.69 and 125.55 ppm and against C. quinquefasciatus were 33.23, 82.20 and 215.19 ppm, respectively. Hexane, acetone and methanol extracts of leaves also showed potency against A. aegypti with LC50 values of 133.80, 177.20 and 79.48 and against C. quinquefasciatus with LC50 values of 164.53, 175.28 and 87.87 ppm, respectively .These results suggested that T. asiatica is promising as larvicide against both targeted mosquitoes

Are Machine Learning Based Intrusion Detection System Always Secure?:An insight into tampered learning

Machine learning is successful in many applications including securing a network from unseen attack. The application of learning algorithm for detecting anomaly in a Network has been fundamental since few years. With increasing use of machine learning techniques it has become important to study to what extent it is good to be dependent on them. Altogether a different discipline called ‘Adversarial Learning’ have come up as a separate dimension of study. The work in this paper is to test the robustness of online machine learning based IDS to carefully crafted packets by attacker called poison packets. The objective is to observe how a remote attacker can deviate the normal behavior of machine learning based classifier in the IDS by injecting the network with carefully crafted packets externally, that may seem normal by the classification algorithm and the instance made part of its future training set. This behavior eventually can lead to a poison learning by the classification algorithm in the long run, resulting in misclassification of true attack instances. This work explores one such approach with SOM and SVM as the online learning based classification algorithms

Dependence of the 0.5(2e2/h) conductance plateau on the aspect ratio of InAs quantum point contacts with in-plane side gates

The observation of a 0.5 conductance plateau in asymmetrically biased quantum point contacts with in-plane side gates has been attributed to the onset of spin-polarized current through these structures. For InAs quantum point contacts with the same width but longer channel length, there is roughly a fourfold increase in the range of common sweep voltage applied to the side gates over which the 0.5 conductance plateau is observed when the QPC aspect ratio (ratio of length over width of the narrow portion of the structure) is increased by a factor 3. Non-equilibrium Green s function simulations indicate that the increase in the size of the 0.5 conductance plateau is due to an increased importance, over a larger range of common sweep voltage, of the effects of electron-electron interactions in QPC devices with larger aspect ratio. The use of asymmetrically biased QPCs with in-plane side gates and large aspect ratio could therefore pave the way to build robust spin injectors and detectors for the successful implementation of spin field effect transistorsComment: 30 pages, 9 figure

Studies on the growth behavior of Chlorella, Haematococcus and Scenedesmus sp. in culture media with different concentrations of sodium bicarbonate and carbon dioxide gas

Growth studies were conducted on green algae Chlorella, Scenedesmus and Haematococcus strains in batch mode cultures. In this study, the effect of sodium bicarbonate salt (NaHCO3) and carbon dioxide (CO2) gas as carbon source on microalgal cultures were investigated. For this purpose, growth response of the aforementioned three strains under varying concentrations of NaHCO3 (15, 30, 45, 60 and 75 mg/L,) and CO2 gas (7929, 4758 and 4400 mg/L,) were investigated. The best growth response showed by chlorella strain was observed at 75 mg/L (ppm) bicarbonate (% increase in biomass=82.6mg/L/day for 12 days) and 4758 mg/L CO2 gas concentration (189.1 mg/L/day for 7 days). While Haematococcus strain showed its best growth in 30 ppm bicarbonate (72.9 mg/L/day for 17 days) and 4758 mg/L CO2 gas (134.1 mg/L for 7 days), the Scenedesmus strain showed its best growth in 45 ppm bicarbonate (30.9 mg/L/day for 17 days) and 4758 mg/L CO2 gas (103.8 mg/L for 7 days). All the strains showed good growth when CO2 gas was supplied in terms of increase in cell number, biomass and lipid content compared to bicarbonate utilization as carbon source, except Haematococcus strain which fail to grow when high concentration of CO2 gas (7929 ppm) was supplied. Out of the three strains, it was Chlorella sp. which showed highest growth rate and lipid content when CO2 gas was supplied, (specific growth=0.704; 189.1% increase in biomass, g/L/day and 1.015 doubling/day, 31% lipid content in terms of dry cell weight).Key words: Microalgae, bicarbonate, biomass, lipid

Isotope Shifts in the 7 s → 8 s Transition of Francium: Measurements and Comparison to ab initio Theory

We observe the electric-dipole forbidden 7s→8s transition in the francium isotopes 208−211Fr and 213Fr using a two-photon excitation scheme. We collect the atoms online from an accelerator and confine them in a magneto-optical trap for the measurements. In combination with previous measurements of the 7s→7p1/2 transition we perform a King plot analysis. We compare the thus-determined ratio of the field shift constants (1.228 ± 0.019) to results obtained from new ab initio calculations (1.234 ± 0.010)