41 research outputs found
Surgical management of giant Brunner's gland hamartoma: case report and literature review
Brunner's gland hamartomas (BGH) are uncommon benign tumors of the duodenum forming mature Brunner's glands. We report here an unusual case of a giant BGH that was not amenable to endoscopic or surgical local resection thus requiring a pancreaticoduodenectomy for extirpation. The relevant literature is discussed
Spin relaxation of conduction electrons in bulk III-V semiconductors
Spin relaxation time of conduction electrons through the Elliot-Yafet,
D'yakonov-Perel and Bir-Aronov-Pikus mechanisms is calculated theoretically for
bulk GaAs, GaSb, InAs and InSb of both - and -type. Relative importance
of each spin relaxation mechanism is compared and the diagrams showing the
dominant mechanism are constructed as a function of temperature and impurity
concentrations. Our approach is based upon theoretical calculation of the
momentum relaxation rate and allows understanding of the interplay between
various factors affecting the spin relaxation over a broad range of temperature
and impurity concentration.Comment: an error in earlier version correcte
Cosmological Models of Gamma-Ray Bursts
We review models of cosmological gamma-ray bursts (GRBs). The statistical and
-ray transparency issues are summarized. Neutron-star and black-hole
merger scenarios are described and estimates of merger rates are summarized. We
review the simple fireball models for GRBs and the recent work on non-simple
fireballs. Alternative cosmological models, including models where GRBs are
analogs of active galactic nuclei and where they are produced by high-field,
short period pulsars, are also mentioned. The value of neutrino astronomy to
solve the GRB puzzle is briefly reviewed.Comment: 12 pages, no figures, uuencoded compressed postscript file. Invited
review to appear in the proceedings of the 29th ESLAB Symposium "Towards the
Source of Gamma-Ray Bursts," Noordwijk, Netherlands, 25-27 April, 199