The connection between Gamma-Ray Bursts (GRBs) and their afterglows is currently not well understood. Afterglow models of synchrotron emission generated by external shocks in the GRB fireball model predict emission detectable in the gamma-ray regime (>∼ 25 keV). In this paper, we present a temporal and spectral analysis of a subset of BATSE GRBs with smooth extended emission tails to search for...

We derive a self similar solution for the propagation of an extreme relativistic (or Newtonian) radiative spherical blast wave into a surrounding cold medium. The solution is obtained under the assumption that the radiation process is fast, it takes place only in the vicinity of the shock and that it radiates away a fixed fraction of the energy generated by the shock. In the Newtonian regime th...

The hard X-ray and γ-ray phenomenology of gamma-ray bursts (GRBs) can be explained by an external shock model where a single relativistic blast wave interacts with the surrounding medium. Besides reproducing the generic spectral behavior of GRB profiles, the external shock model provides quantitative fits to the peak flux distribution, the > 1 s t50 duration distribution, and the distribution o...

We use general arguments to show that a continuously powered radiative blast wave can behave self similarly if the energy injection and radiation mechanisms are self similar. In that case, the power-law indices of the blast wave evolution are set by only one of the two constituent physical mechanisms. If the luminosity of the energy source drops fast enough, the radiation mechanisms set the pow...

In a recent study of the pathophysiology of mild, blast-induced traumatic brain injury (bTBI) the exposure of dissociated, central nervous system (CNS) cells to simulated blast resulted in propagating waves of elevated intracellular Ca(2+). Here we show, in dissociated human CNS cultures, that these calcium waves primarily propagate through astrocyte-dependent, purinergic signaling pathways tha...

Traumatic brain injuries (TBI) caused by improvised explosive devices (IEDs) affect a significant percentage of surviving soldiers wounded in Iraq and Afghanistan. The extent of a blast TBI, especially initially, is difficult to diagnose, as internal injuries are frequently unrecognized and therefore underestimated, yet problems develop over time. Therefore it is paramount to resolve the physic...

The blast wave that is generated from the detonation of an anti-personnel mine can induce significant accelerative loading to the head of a deminer, when the wave collides with the victim. The injury potential posed by the resulting head acceleration in the context of demining, has not been previously studied. Instrumented anthropomorphic surrogates were used to evaluate the protective capabili...

Blast-induced traumatic brain injury (bTBI) has been linked to a multitude of delayed-onset neurodegenerative and neuropsychiatric disorders, but complete understanding of their pathogenesis remains elusive. To develop mechanistic relationships between bTBI and post-blast neurological sequelae, it is imperative to characterize the initiating traumatic mechanical events leading to eventual alter...

Traumatic brain injury (TBI) has been diagnosed in nearly 300,000 members of the US armed forces since 2000 [1]. Common symptoms of these injuries include concussion, loss of spatial navigation, behavior/mood changes and memory loss [2‐3]. Blast‐related TBI poses a significant problem for military personnel both in combat and in training. Primary blast loading, the blast loading caused by the i...

We use general arguments to show that a continuously powered radiative blast wave can behave self similarly if the energy injection and radiation mechanisms are self similar. In that case, the power-law indices of the blast wave evolution are set by only one of the two constituent physical mechanisms. If the luminosity of the energy source drops fast enough, the radiation mechanisms set the pow...