486 research outputs found
Nilpotent Gauging of SL(2,R) models, and Liouville Field
We consider the gauging of WZNW model by its nilpotent subgroup
E(1). The resulting space-time of the corresponding sigma model is seen to
collapse to a one dimensional field theory of Liouville. Gauging the diagonal
subgroup of theory yields an
extremal three dimensional black string. We show that these solutions are
obtained from the two dimensional black hole of Witten and the three
dimensional black string of Horne and Horowitz by boosting the gauge group.Comment: 17 pages, late
High resolution frequency to time domain transformations applied to the stepped carrier MRIS measurements
Two narrow-band radar systems are developed for high resolution target range estimation in inhomogeneous media. They are reformulations of two presently existing systems such that high resolution target range estimates may be achieved despite the use of narrow bandwidth radar pulses. A double sideband suppressed carrier radar technique originally derived in 1962, and later abandoned due to its inability to accurately measure target range in the presence of an interfering reflection, is rederived to incorporate the presence of an interfering reflection. The new derivation shows that the interfering reflection causes a period perturbation in the measured phase response. A high resolution spectral estimation technique is used to extract the period of this perturbation leading to accurate target range estimates independent of the signal-to-interference ratio. A non-linear optimal signal processing algorithm is derived for a frequency-stepped continuous wave radar system. The resolution enhancement offered by optimal signal processing of the data over the conventional Fourier Transform technique is clearly demonstrated using measured radar data. A method for modeling plane wave propagation in inhomogeneous media based on transmission line theory is derived and studied. Several simulation results including measurement of non-uniform electron plasma densities that develop near the heat tiles of a space re-entry vehicle are presented which verify the validity of the model
Gauge Invariant Cutoff QED
A hidden generalized gauge symmetry of a cutoff QED is used to show the
renormalizability of QED. In particular, it is shown that corresponding Ward
identities are valid all along the renormalization group flow. The exact
Renormalization Group flow equation corresponding to the effective action of a
cutoff lambda phi^4 theory is also derived. Generalization to any gauge group
is indicated.Comment: V1: 18 pages, 2 figures; V2: Discussions improved. Version accepted
for publication in Physica Script
Nutritional value of Jack knife clam Solen dactylus in the ripeness and sexual rest stages
In this study, 60 specimens of Jack knife clam Solen dactylus (Von Cosel, 1989) were collected randomly in autumn 2007 and spring 2008 from 5 stations (intertidal pools) in Golshahr coast of Bandar Abbas, Persian Gulf. After sampling, specimens were frozen and transferred to the laboratory for further biometric parameters measurements. The mean (±SD) anterior- posterior length in autumn and spring were 78.92±17.72 and 77.37±16.20mm, respectively. The mean (±SD) total weight was 9.53±4.88g in autumn and 8.43±4.46g in spring. Moisture, ash, protein and total lipid in soft tissues of clams were measured. These parameters in autumn and spring were 80.23 ± 0.70, 3.42±0.02, 11.3±0.10, 0.86±0.01% and 76.16±1.75, 2.3±0.07, 11.79±0.05, 0.55±0.02%, respectively. The values of moisture, ash and total lipid were higher in autumn (ripeness stage) compared to spring; whereas, the value of protein in autumn was slightly lower than spring. There was no significant difference between the mean of moisture before and after the spawning (P>0.05). The mean ash, protein and total lipid showed a significant difference in the two seasons (P<0.05)
Dirac Quantization of Open Strings and Noncommutativity in Branes
We apply the Dirac bracket quantization to open strings attached to branes in
the presence of background antisymmetric field and recover an inherent
noncommutativity in the internal coordinates of the brane.Comment: 25 pp, typos corrected, minor change
Effect of 17- alpha- methyl testosterone on cichlid kaliko (Labeotropheous foellobroni) sex reversal
In this present study, Cichlid Kaliko (Labeotropheous foellobroni) fallowing was exposed to 17-alpha-methyl testosterone at 2 stages of development including prior to maturity (larvae) and after puberty (broodstock). The influence of sex hormone on the larvae was also explored. The first group was the larvae under the four treatments (0, 50,100, 250) mg per kg of food and hormones that broodstock group also included four treatments (0, 100, 250, 400) mg per kg food three replicates were performed in a period of 30 days. Hormone was added to fish food. Results showed that treatments had a significant difference in fish growth, which correlated with increased amounts of 17 alpha-methyl testosterone. In group I, food with 250mg/kg testerone resulted in an increase in growth indices (i.e.s, SGR=1.4, ADG= 6.5) with a mortality rate of 48.3 percent. In group II results showed that treatment of G (400mg testosterone per kg food) produced larvae with maximum growth indices (SGR=0.91, ADG= 3.6) and the least mortality rate of 31 percent; Research revealed that 17 alpha methyl testosterone could have an effect on Calico fish sex changes in both larval and stock stages
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