1,671 research outputs found
Short gamma-ray bursts from binary neutron star mergers in globular clusters
The first locations of short gamma-ray bursts (GRBs) in elliptical galaxies
suggest they are produced by the mergers of double neutron star (DNS) binaries
in old stellar populations. Globular clusters, where the extreme densities of
very old stars in cluster cores create and exchange compact binaries
efficiently, are a natural environment to produce merging NSs. They also allow
some short GRBs to be offset from their host galaxies, as opposed to DNS
systems formed from massive binary stars which appear to remain in galactic
disks. Starting with a simple scaling from the first DNS observed in a galactic
globular, which will produce a short GRB in ~300My, we present numerical
simulations which show that ~10-30% of short GRBs may be produced in globular
clusters vs. the much more numerous DNS mergers and short GRBs predicted for
galactic disks. Reconciling the rates suggests the disk short GRBs are more
beamed, perhaps by both the increased merger angular momentum from the DNS
spin-orbit alignment (random for the DNS systems in globulars) and a larger
magnetic field on the secondary NS.Comment: 13 pages, 2 figures, accepted for publication in Nature Physics (Feb.
2006
Enhanced recovery after surgery
Enhanced Recovery or Fast Track Recovery after Surgery protocols (ERAS) have significantly changed perioperative care following colorectal surgery and are promoted as reducing the stress response to surgery.
The present systematic review aimed to examine the impact on the magnitude of the systemic inflammatory response (SIR) for each ERAS component following colorectal surgery using objective markers such as C-reactive protein (CRP) and interleukin-6 (IL-6).
A literature search was performed of the US National Library of Medicine (MEDLINE), EMBASE, PubMed, and the Cochrane Database of Systematic Reviews using appropriate keywords and subject headings to February 2015.
Included studies had to assess the impact of the selected ERAS component on the SIR using either CRP or IL-6.
Nineteen studies, including 1898 patients, were included. Fourteen studies (1246 patients) examined the impact of laparoscopic surgery on the postoperative markers of SIR. Ten of these studies (1040 patients) reported that laparoscopic surgery reduced postoperative CRP. One study (53 patients) reported reduced postoperative CRP using opioid-minimising analgesia. One study (142 patients) reported no change in postoperative CRP following preoperative carbohydrate loading. Two studies (108 patients) reported conflicting results with respect to the impact of goal-directed fluid therapy on postoperative IL-6. No studies examined the effect of other ERAS components, including mechanical bowel preparation, antibiotic prophylaxis, thromboprophylaxis, and avoidance of nasogastric tubes and peritoneal drains on markers of the postoperative SIR following colorectal surgery.
The present systematic review shows that, with the exception of laparoscopic surgery, objective evidence of the effect of individual components of ERAS protocols in reducing the stress response following colorectal surgery is limited
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