A theory of tidal mixing in a vertically homogeneous estuary

An equation is derived for the distribution of a solute in an estuary where river flow and tides are predominant factors and where the dynamics and mixing can be described by a simple physical model. This model is subsequently generalized in various ways and it is found that the basic form of the diffusion equation is unchanged. An equation is derived which allows for time dependence of the varioUB quantities involved and for introduction of a solute into the estuary by an external agent. Some solutions of this equation are studied

Electron and Photon Energy Deposition in Universe

We consider energy deposition of high energy electrons and photons in universe. We carry out detailed calculations of fractions of the initial energy of the injected electron or photon which are used to heat, ionize and excite background plasma in the early universe for various ionization states and redshifts.Comment: 21 pages, 12 figure

A New Frequency-Luminosity Relation for Long GRBs?

We have studied power density spectra (PDS) of 206 long Gamma-Ray Bursts (GRBs). We fitted the PDS with a simple power-law and extracted the exponent of the power-law (alpha) and the noise-crossing threshold frequency (f_th). We find that the distribution of the extracted alpha peaks around -1.4 and that of f_th around 1 Hz. In addition, based on a sub-set of 58 bursts with known redshifts, we show that the redshift-corrected threshold frequency is positively correlated with the isotropic peak luminosity. The correlation coefficient is 0.57 +/- 0.03.Comment: 9 pages, 17 figures, 1 table; Accepted for publication in MNRA

Radiative Corrections to Electron-Proton Scattering

The radiative corrections to elastic electron-proton scattering are analyzed in a hadronic model including the finite size of the nucleon. For initial electron energies above 8 GeV and large scattering angles, the proton vertex correction in this model increases by at least two percent the overall factor by which the one-photon exchange (Rosenbluth) cross section must be multiplied. The contribution of soft photon emission is calculated exactly. Comparison is made with the generally used expressions previously obtained by Mo and Tsai. Results are presented for some kinematics at high momentum transfer.Comment: 31 pages, 4 figure

Spectral Lags of Gamma-Ray Bursts from Primordial Black Hole (PBH) Evaporations

Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. PBHs with an initial mass of 5.0 * 10^14 g should be expiring today with a burst of high energy particles. Evaporating PBHs in the solar neighborhood are candidate Gamma-Ray Bursts (GRBs) progenitors. We propose spectral lag, which is the temporal delay between the high energy photon pulse and the low energy photon pulse, as a possible method to detect PBH evaporation events with the Fermi Gamma-ray Space Telescope Observatory.Comment: 3 pages; Published in the proceedings of Huntsville 2008 symposium on GRBs; Indices in Equation 7 and 8 correcte

The Minimum Variability Time Scale and its Relation to Pulse Profiles of Fermi GRBs

We present a direct link between the minimum variability time scales extracted through a wavelet decomposition and the rise times of the shortest pulses extracted via fits of 34 Fermi GBM GRB light curves comprised of 379 pulses. Pulses used in this study were fitted with log-normal functions whereas the wavelet technique used employs a multiresolution analysis that does not rely on identifying distinct pulses. By applying a corrective filter to published data fitted with pulses we demonstrate agreement between these two independent techniques and offer a method for distinguishing signal from noise.Comment: Accepted for publication in MNRAS Letters. 4 pages, 4 figure

The Hurst Exponent of Fermi GRBs

Using a wavelet decomposition technique, we have extracted the Hurst exponent for a sample of 46 long and 22 short Gamma-ray bursts (GRBs) detected by the Gamma-ray Burst Monitor (GBM) aboard the Fermi satellite. This exponent is a scaling parameter that provides a measure of long-range behavior in a time series. The mean Hurst exponent for the short GRBs is significantly smaller than that for the long GRBs. The separation may serve as an unbiased criterion for distinguishing short and long GRBs.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Radiative Correction to the Transferred Polarization in Elastic Electron-Proton Scattering

Model independent radiative correction to the recoil proton polarization for the elastic electron-proton scattering is calculated within method of electron structure functions. The explicit expressions for the recoil proton polarization are represented as a contraction of the electron structure and the hard part of the polarization dependent contribution into cross-section. The calculation of the hard part with first order radiative correction is performed. The obtained representation includes the leading radiative corrections in all orders of perturbation theory and the main part of the second order next-to-leading ones. Numerical calculations illustrate our analytical results.Comment: 14 pages, 4 figure