Understanding the effects of geometry and rotation on pulsar intensity profiles

We have developed a method to compute the possible distribution of radio emission regions in a typical pulsar magnetosphere, taking into account the viewing geometry and rotational effects of the neutron star. Our method can estimate the emission altitude and the radius of curvature of particle trajectory as a function of rotation phase for a given inclination angle, impact angle, spin-period, Lorentz factor, field line constant and the observation frequency. Further, using curvature radiation as the basic emission mechanism, we simulate the radio intensity profiles that would be observed from a given distribution of emission regions, for different values of radio frequency and Lorentz factor. We show clearly that rotation effects can introduce significant asymmetries into the observed radio profiles. We investigate the dependency of profile features on various pulsar parameters. We find that the radiation from a given ring of field lines can be seen over a large range of pulse longitudes, originating at different altitudes, with varying spectral intensity. Preferred heights of emission along discrete sets of field lines are required to reproduce realistic pulsar profiles, and we illustrate this for a known pulsar. Finally, we show how our model provides feasible explanations for the origin of core emission, and also for one-sided cones which have been observed in some pulsars.Comment: 21 pages, 11 figures, accepted for publication in MNRA

Combining Ability in African Marigold (Tagetes erecta L.)

A line x tester crossing programme was done using male sterile lines and a set of 11 genetically diverse pollinators as testers. F1's along with parents were evaluated during winter and summer seasons. During the seasons, for plant height and flower size, additive gene action was higher compared to non-additive gene action, while for flowering days and stalk length, non-additive and non-additive gene actions played important role during both the seasons, indicating the usefulness of hybrids in marigold cultivation. Similarly, for flower number during winter and for plant spread during summer, both additive and non-additive gene action played significant role. For other traits, gene action was inconsistent during different seasons

Chiral Phase Transition in Lattice QCD with Wilson Quarks

The nature of the chiral phase transition in lattice QCD is studied for the cases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice with the temporal direction extension $N_t=4$. We find that the chiral phase transition is continuous for the case of 2 flavors, while it is of first order for 3 and 6 flavors.Comment: uuencoded compressed tar file, LaTeX, 14 pages, 7 figure

Effect of paclobutrazol and benzyl adenine on oriental lily hybrids

Studies on the effect of growth regulators viz., Paclobutrazol and Benzyl Adenine (PBZ and BA, respectively) on Oriental Lily Hybrids, 'Star Gazer Pink' and 'Star Gazer White' in the second year were carried out at Department of Floriculture and Landscaping, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan (H.P). The effect of growth regulators applied in the first year, was studied on growth and flowering of Oriental lily hybrids in the second year. Plant height and number of leaves plant-1 were recorded maximum when PBZ 25 ppm was applied in the first year. Maximum plant height and number of leaves plant-1 were found in 'Star Gazer White' (84.46 cm; 35.04 cm). Bulbs of 'Star Gazer White' when dipped in PBZ 25 ppm for 12 h in the first year resulted in maximum plant height (102.50 cm) in the second year. Leaf area in the second year was recorded maximum in 'Star Gazer White' (34.40 cm2) when PBZ 50 ppm was applied as bulb dip in the first year. Flower buds were initiated earlier in 'Star Gazer White' (84.48 days) as compared to 'Star Gazer Pink' (85.90 days). Days to bud initiation were also recorded minimum (75.81 days) when PBZ 25 ppm was applied as pre-plant bulb dip. More number of flowers plant-1 was recorded in 'Star Gazer White' (5.42) which lasted longer on stems (16.77 days). Bulbs dipped in growth regulators in the first season produced maximum number of flowers plant-1 (5.72) and duration of flowering was also maximum (18.28 days)

Surfactant induced smooth and symmetric interfaces in Cu/Co multilayers

In this work we studied Ag surfactant induced growth of Cu/Co multilayers. The Cu/Co multilayers were deposited using Ag surfactant by ion beam sputtering technique. It was found that Ag surfactant balances the asymmetry between the surface free energy of Cu and Co. As a result, the Co-on-Cu and Cu-on-Co interfaces become sharp and symmetric and thereby improve the thermal stability of the multilayer. On the basis of obtained results, a mechanism leading to symmetric and stable interfaces in Cu/Co multilayers is discussed.Comment: 7 Pages, 7 Figure

One-dimensional lattice of oscillators coupled through power-law interactions: Continuum limit and dynamics of spatial Fourier modes

We study synchronization in a system of phase-only oscillators residing on the sites of a one-dimensional periodic lattice. The oscillators interact with a strength that decays as a power law of the separation along the lattice length and is normalized by a size-dependent constant. The exponent $\alpha$ of the power law is taken in the range $0 \le \alpha <1$. The oscillator frequency distribution is symmetric about its mean (taken to be zero), and is non-increasing on $[0,\infty)$. In the continuum limit, the local density of oscillators evolves in time following the continuity equation that expresses the conservation of the number of oscillators of each frequency under the dynamics. This equation admits as a stationary solution the unsynchronized state uniform both in phase and over the space of the lattice. We perform a linear stability analysis of this state to show that when it is unstable, different spatial Fourier modes of fluctuations have different stability thresholds beyond which they grow exponentially in time with rates that depend on the Fourier modes. However, numerical simulations show that at long times, all the non-zero Fourier modes decay in time, while only the zero Fourier mode (i.e., the "mean-field" mode) grows in time, thereby dominating the instability process and driving the system to a synchronized state. Our theoretical analysis is supported by extensive numerical simulations.Comment: 7 pages, 4 figures. v2: new simulation results added, close to the published versio

Using Absorption Imaging to Study Ion Dynamics in an Ultracold Neutral Plasma

We report optical absorption imaging of ultracold neutral plasmas.Images are used to measure the ion absorption spectrum, which is Doppler-broadened. Through the spectral width, we monitor ion equilibration in the first 250ns after plasma formation. The equilibration leaves ions on the border between the weakly coupled gaseous and strongly coupled liquid states. On a longer timescale of microseconds, we observe radial acceleration of ions resulting from pressure exerted by the trapped electron gas.Comment: 4 pages, 4 figure