Introduction Nanocrystalline gamma-phase (γ) alumina is among many polytypes of alumina that find extensive applications as a catalyst and catalytic supports. The most useful properties these aluminas provide as catalyst supports are high surface area and welldefined porosity. These properties result primarily from the nano-scale crystalline character of the alumina. The problem is that both th...

This paper presents an interpretation based on gamma-ray burst source kinematics for the relationship found by Norris et al. between peak luminosity and energy-dependent pulse lag. I argue that the correlation should instead be between number luminosity and pulse lag. This interpretation improves the least-squares fit of this correlation for the known bursts by 25 percent or more. It also sugge...

Ground-based detection of very high energy gamma rays at Tev energies is discussed by using as example the emission from pulsar nebulae and supernova remnants. Copious production of electrons and positrons characterizes the point sources of gamma rays, and the radiation of electrons links TeV region tightly to the other bands, giving us the means of the `multi-wavelengths analysis' to investiga...

We compute the kinematical dependence of the peak luminosity, the pulse width and the spectral lag of the peak luminosity on the viewing angle θv of a jet. For appropriate model parameters we obtain the peak luminosity-spectral lag relation similar to the observed one including GRB980425. A bright (dim) peak with short (long) spectral lag corresponds to a jet with small (large) viewing angle. T...

Clusters of galaxies and the large scale filaments that connect neighboring clusters are expected to be sites of acceleration of charged particles and sources of non-thermal radiation from radio frequencies to gamma rays. Gamma rays are particularly interesting targets of investigation, since they may provide precious information on the nature and efficiency of the processes of acceleration and...

The most recent member of the millisecond pulsar with very low mass companions and short orbital periods class, PSR J1311−3430 (Pletsch et al. 2012) is a remarkable object in various senses. Besides being the first discovered in gamma rays, its measured features include the very low or absent hydrogen content. We show in this Letter that this important piece of information leads to a very restr...

We establish the existence of Adams operations on the members of a ltration of K-theory which is deened using products of projective lines. We also show that this ltration induces the gamma ltration on the rational K-groups of a smooth variety over a eld of characteristic zero.

Passive anaphylaxis of the guinea pig has been subjected to numerous immunological studies (1). They have established for both systemic (2) and cutaneous anaphylaxis (3) the levels of specific antibody required, and the need for a latent period of sensitization (4, 5) which is generally believed to be the time required for the binding of the antibody to tissue receptors. Further evidence for an...

In gamma-ray burst research it is quite common to fit the afterglow light curves with a broken power law to interpret the data. We apply this method to a computer simulated population of afterglows and find systematic differences between the known model parameters of the population and the ones derived from the power law fits. In general, the slope of the electron energy distribution is overest...