Dilepton asymmetries at BB factories in search of ΔB=−ΔQ\Delta B =- \Delta Q transitions

In order to detect the possible presence of $\Delta B = - \Delta Q$ amplitudes in neutral $B$ meson decays, we consider the measurement of decay time asymmetries involving like-sign dilepton events at the $B$ factories.Comment: 5 pages, latex, no fig

A Simple Model for Pulse Profiles from Precessing Pulsars, with Special Application to Relativistic Binary PSR B1913+16

We study the observable pulse profiles that can be generated from precessing pulsars. A novel coordinate system is defined to aid visualization of the observing geometry. Using this system we explore the different families of profiles that can be generated by simple, circularly symmetric beam shapes. An attempt is then made to fit our model to the observations of relativistic binary PSR B1913+16. It is found that while qualitatively similar pulse profiles can be produced, this minimal model is insufficient for an accurate match to the observational data. Consequently, we confirm that the emission beam of PSR B1913+16 must deviate from circular symmetry, as first reported by Weisberg and Taylor. However, the approximate fits obtained suggest that it may be sufficient to consider only minimal deviations from a circular beam in order to explain the data. We also comment on the applicability of our analysis technique to other precessing pulsars, both binary and isolated.Comment: 35 pages and 8 figures. Published versio

Iron and molybdenum valences in double-perovskite (Sr,Nd)2FeMoO6: electron-doping effect

Double perovskite, (Sr1-xNdx)2FeMoO6, was doped with electrons through partial substitution of divalent Sr by trivalent Nd (0 < x < 0.2). The Fe valence and the degree of B-site order were probed by 57Fe Mossbauer spectroscopy. Replacing Sr by Nd increased the fraction of Fe and Mo atoms occupying wrong sites, i.e. antisite disorder. It had very little effect on the Fe valence: a small but visible increase in the isomer shift was seen for the mixed-valent FeII/III atoms occupying the right site indicating a slight movement towards divalency of these atoms, which was more than counterbalanced by the increase in the fraction of antisite Fe atoms with III valence state. It is therefore argued that the bulk of the electron doping is received by antisite Mo atoms, which - being surrounded by six MoV/VI atoms - prefer the lower IV/V valence state. Thus under Nd substitution, the charge-neutrality requirement inflicts a lattice disorder such that low-valent MoIV/V can exist.Comment: 15 pages, 6 figures, to appear in Solid State Commu

Egg-laying rhythm in Drosophila melanogaster

Extensive research has been carried out to understand how circadian clocks regulate various physiological processes in organisms. The discovery of clock genes and the molecular clockwork has helped researchers to understand the possible role of these genes in regulating various metabolic processes. In Drosophila melanogaster, many studies have shown that the basic architecture of circadian clocks is multi-oscillatory. In nature, different neuronal subgroups in the brain of D. melanogaster have been demonstrated to control different circadian behavioural rhythms or different aspects of the same circadian rhythm. Among the circadian phenomena that have been studied so far in Drosophila, the egg-laying rhythm is unique, and relatively less explored. Unlike most other circadian rhythms, the egg-laying rhythm is rhythmic under constant light conditions, and the endogenous or free-running period of the rhythm is greater than those of most other rhythms. Although the clock genes and neurons required for the persistence of adult emergence and activity/rest rhythms have been studied extensively, those underlying the circadian egg-laying rhythm still remain largely unknown. In this review, we discuss our current understanding of the circadian egg-laying rhythm in D. melanogaster, and the possible molecular and physiological mechanisms that control the rhythmic output of the egg-laying process

Factorization of the charge correlation function in B0Bˉ0B^0\bar B^0 oscillations

Extraction of the mass difference $\Delta m$ from $B^0\bar B^0$ oscillations involves tagging of bottom flavour at production and at decay. We show that the asymmetry between the unmixed and mixed events factorizes into two parts, one depending on the production-tag and the other on the decay-tag.Comment: 6 pages, Latex, no figure

Finite Size Effects for the Ising Model Coupled to 2-D Random Surfaces

Finite size effects for the Ising Model coupled to two dimensional random surfaces are studied by exploiting the exact results from the 2-matrix models. The fixed area partition function is numerically calculated with arbitrary precision by developing an efficient algorithm for recursively solving the quintic equations so encountered. An analytic method for studying finite size effects is developed based on the behaviour of the free energy near its singular points. The generic form of finite size corrections so obtained are seen to be quite different from the phenomenological parameterisations used in the literature. The method of singularities is also applied to study the magnetic susceptibility. A brief discussion is presented on the implications of these results to the problem of a reliable determination of string susceptibility from numerical simulations.Comment: 18 pages, 3 figure

Performance of Hereford Crossbred and Kedah-Kelantan Cattle fed a Palm Kernel Cake-based Ration

In a feeding experiment involving the use of a PKC-based ration for·105 days, the average daily feed intake of 3.11 and 3.31 kg in Hereford crossbred and Kedah-Kelantan cattle respectively, was found to be not significant. Hereford crossbred cattle had an average daily gain of O.712 kg which was significantly higher (P < 0.05) than that of Kedah-Kelantan cattle (0.586 kg). Similarly Hereford crossbred cattle had a significantly better (P < 0.01) feed efficiericy (4.37) compared to that of Kedah-Kelantan cattle (5.71). The income overfeed cost per animal per day was $1.344 and$0.514 in Hereford crossbred and Kedah-Kelantan cattle respectively

Two-Dimensional Dynamical Triangulation using the Grand-canonical Ensemble

The string susceptibility exponents of dynamically triangulated two dimensional surfaces with sphere and torus topology were calculated using the grand-canonical Monte Carlo method. We also simulated the model coupled to d-Ising spins (d=1,2,3,5).Comment: 3 pages, latex, 2 ps-figures, uses espcrc2.sty. Talk presented at LATTICE'97(gravity

Moisture Stable Soot Coated Methylammonium Lead Iodide Perovskite Photoelectrodes for Hydrogen Production in Water

Metal halide perovskites have triggered a quantum leap in the photovoltaic technology marked by a humongous improvement in the device performance in a matter of just a few years. Despite their promising optoelectronic properties, their use in the photovoltaic sector remains restricted due to their inherent instability towards moisture. Here, we report a simple, cost-effective and highly efficient protection strategy that enables their use as photoelectrodes for photoelectrochemical hydrogen production while being immersed in water. A uniform coating of candle soot and silica is developed as an efficient hydrophobic coating that protects the perovskite from water while allowing the photogenerated electrons to reach the counter electrode. We achieve remarkable stability with photocurrent density above 1.5 mA cm−2 at 1 V versus saturated calomel electrode (SCE) for ~1 h under constant illumination. These results indicate an efficient route for the development of stable perovskite photoelectrodes for solar water splittin