Primordial Magnetic Fields in the Post-recombination Era and Early Reionization

We explore the ways in which primordial magnetic fields influence the thermal and ionization history of the post-recombination universe. After recombination the universe becomes mostly neutral resulting also in a sharp drop in the radiative viscosity. Primordial magnetic fields can then dissipate their energy into the intergalactic medium (IGM) via ambipolar diffusion and, for small enough scales, by generating decaying MHD turbulence. These processes can significantly modify the thermal and ionization history of the post-recombination universe. We show that the dissipation effects of magnetic fields which redshifts to a present value $B_{0}=3\times 10^{-9}$ Gauss smoothed on the magnetic Jeans scale and below, can give rise to Thomson scattering optical depths \tau \ga 0.1, although not in the range of redshifts needed to explain the recent WMAP polarization observations. We also study the possibility that primordial fields could induce the formation of subgalactic structures for z \ga 15. We show that early structure formation induced by nano-Gauss magnetic fields is potentially capable of producing the early re-ionization implied by the WMAP data. Future CMB observations will be very useful to probe the modified ionization histories produced by primordial magnetic field evolution and constrain their strength.Comment: 19 pages, 7 figures, Minor changes to match version accepted in MNRA

Generation of Magnetic Field in the Pre-recombination Era

We study the possibility of generating magnetic fields during the evolution of electron, proton, and photon plasma in the pre-recombination era. We show that a small magnetic field can be generated in the second order of perturbation theory for scalar modes with adiabatic initial conditions. The amplitude of the field is \la 10^{-30} \rm G at the present epoch for scales from sub-kpc to \ga 100 \rm Mpc.Comment: 8 page

Relation between hyponatremia and alteration in gross metabolic parameters after atypical antipsychotic therapy

Background: Weight gain and hyponatremia which is dilutional in nature, has been well known adverse effects associated with use of atypical antipsychotic medication but the plausible impact of dilutional hyponatremia on weight gain has not been explored.Methods: One hundred and three patients more than 18 years of age of either gender who were prescribed, olanzapine or risperidone, were tested for serum electrolytes (Na+ and K+) and gross metabolic parameters (weight and waist circumference) were measured for baseline and post drug testing.Results: Most common age group was 30-39 years of age in the patient study sample (n=103) with 38 (36.90%) patients were females while rest 63 (63.10%) were males. There was no significant association between serum sodium levels and weight gain was observed (p >0.05). It was observed that in olanzapine group 64% of the studied cases had weight gain whereas in risperidone group only 20.8% reported weight gain (p 0.05).Conclusions: Olanzapine was primarily responsible for weight gain and increase in waist circumference over risperidone. These gross metabolic parameters were not influenced by hyponatremia

On the Clustering of GRBs on the Sky

The two-point correlation of the 4th (current) BATSE catalog (2494 objects) is calculated. It is shown to be consistent with zero at nearly all angular scales of interest. Assuming that GRBs trace the large scale structure in the universe we calculate the angular correlation function for the standard CDM (sCDM) model. It is shown to be $\le 10^{-4}$ at $\theta \simeq 5^\circ$ if the BATSE catalog is assumed to be a volume-limited sample up to $z \simeq 1$. Combined with the error analysis on the BATSE catalog this suggests that nearly $10^5$ GRBs will be needed to make a positive detection of the two-point angular correlation function at this angular scale.Comment: 5 pages, Latex with aipproc.sty, incl. 1 ps-Fig., Proc. of the 5th Huntsville Gamma Ray Burst Symposium, Oct. 1999, ed. R.M. Kippen, AI

Galactic dust polarized emission at high latitudes and CMB polarization

We estimate the dust polarized emission in our galaxy at high galactic latitudes, which is the dominant foreground for measuring CMB polarization using the high frequency instrument (HFI) aboard Planck surveyor. We compare it with the level of CMB polarization and conclude that, for angular scales $\le 1^{\circ}$, the scalar-induced CMB polarization and temperature-polarization cross-correlation are much larger than the foreground level at $\nu \simeq 100 GHz$. The tensor-induced signals seem to be at best comparable to the foreground level.}Comment: Latex document, 4 pages, 2 figures, to appear in "Fundamental parameters in Cosmology", Rencontres de Moriond, 199