Electron bunch timing with femtosecond precision in a superconducting free-electron laser.

High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders of magnitude higher than at other existing x-ray sources. In order to fully exploit the opportunities offered by these femtosecond light pulses in time-resolved experiments, an unprecedented synchronization accuracy is required. In this Letter, we distributed the pulse train of a mode-locked fiber laser with femtosecond stability to different locations in the linear accelerator of the soft x-ray FEL FLASH. A novel electro-optic detection scheme was applied to measure the electron bunch arrival time with an as yet unrivaled precision of 6 fs (rms). With two beam-based feedback systems we succeeded in stabilizing both the arrival time and the electron bunch compression process within two magnetic chicanes, yielding a significant reduction of the FEL pulse energy jitter.

First results from the CERN axion solar telescope.

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

[Comparative analysis of vascular injuries during times of peace and war]. / Uporedna analiza mirnodopskih i ratnih vaskularnih povreda.

The authors present results of reconstructive surgical procedures in 127 non-war and 59 war vascular injures operated on in the last ten and 2 years, respectively. Non-war injures were dominated by blunt trauma, while fire arms and explosives caused most of war injuries. Two thirds of the patients were subjected to primary, and one third to secondary operations. As much as 85% of secondary operations were made in cases of war injuries. The most common reasons for inappropriate primary operations were: incomplete diagnostics, inappropriate surgical procedure and technical errors. About two thirds of the cases were isolated vascular injuries, and one third were combined injuries where in addition to blood vessels, bones and peripheral nerves were also affected. Topographically, the upper and lower extremities were most commonly affected. Most of the operations were complex reconstructive procedures such as graft interpositions or by-passes, and less frequently only suture of a blood vessel or end-to-end anastomosis were made. Fasciotomy was an auxillary method used in all patients with late vascularization syndrome, and exposure in a special "tent" in patients with wound infection. Early success was noted on 88% of operated patients. In 12% of them amputation was performed. Primary amputation (without attempts of reconstruction) was performed in 4% out of the total number of patients. After primary operations they performed (127) the authors had to undertake amputation because of failure of the primary surgery in 4% of patients, while after secondary reconstructions (primary operations performed elsewhere) amputations were necessitated in 23% out of 57 patients. A significant difference was noted which directly correlated with the number of primary and secondary operations after war (28%) and non-war (6%) injuries.

[Biliary ileus]. / Bilijarni ileus.

In the period 1946-1987 at the former Second Surgical Clinic of the Medical Faculty in Belgrade 25 patients with a biliary ileus were Surgically treated, 20 females (80%), and 5 males (20%), aged from 53 to 87 years, (mean 67 years). Six patients were decade, 7 in 7th, 9 in 8th, and 3 in 9th decade. In only 8 patients biliary calculosis had been confirmed earlier. Preoperative troubles in the Bowel Passage lasted 1-7 days, (mean 3 days), mostly as in incomplete gut occlusion. Preoperative diagnosis of the biliary ileus, using x-ray, was exact only in 3 cases (12%), while other remaining patients underwent Surgery diagnosed as ileus of the small bowel or acute abdomen. In 7 patients a stone obstructed the jejunum, in 6 ones its widpart and in 10 cases the terminal ileum. In 23 patients an enterotomy distally to the obstruction with an expulsion-extraction was done, in one patient a partial resection of the gut and in another patient a manual stone expulsion into the colon, with no enterotomy, was carried out, and after operation the stone was removed from the rectum. The Bilio-digestive fistula was never treated either the surgery itself, or later. Complications arised in 13 patients: wound infection in 11, deep thrombophlebitis in one and a pneumonia in two patients. An average hospitalization was 27 days, and all patients Survived.