Optimization of Monte-Carlo calculations of the effective potential

We study Monte Carlo calculations of the effective potential for a scalar field theory using three techniques. One of these is a new method proposed and tested for the first time. In each case we extract the renormalised quantities of the theory. The system studied in our calculations is a one component $\phi^4$ model in two dimensions. We apply these methods to both the weak and strong coupling regime. In the weak coupling regime we compare our results for the renormalised quantities with those obtained from two-loop lattice perturbation theory. Our results are verified in the strong coupling regime through comparison with the strong coupling expansion. We conclude that effective potential methods, when suitably chosen, can be accurate tools in calculations of the renormalised parameters of scalar field theories.Comment: 26 pages of LaTeX, uses psfig.sty with 6 figures. Entire manuscript available as a postscript file via WWW at http://www.physics.adelaide.edu.au/theory/papers/ADP-97-13.T250-abs.html or via anonymous ftp at ftp://bragg.physics.adelaide.edu.au/pub/theory/ADP-97-13.T250.p

レミフェンタニル麻酔中の１％糖負荷が高齢者の代謝に与える影響 : 無作為対照比較試験

Background: Previous studies showed that remifentanil-induced anesthesia can inhibit surgical stress response in non-diabetic adult patients and that low-dose glucose loading during anesthesia may attenuate fat catabolism. However, little is known about the influence of glucose loading on metabolism in elderly patients, whose condition may be influenced by decreased basal metabolism and increased insulin resistance. We hypothesized that, in elderly patients, intraoperative low glucose infusion may attenuate the catabolism of fat without causing harmful hyperglycemia during remifentanil-induced anesthesia. Methods: Elderly, non-diabetic patients scheduled to undergo elective surgery were enrolled and randomized to receive no glucose (0G group) or low-dose glucose infusion (0.1 g/kg/hr. for 1 h followed by 0.05 g/kg/hr. for 1 h; LG group) during surgery. Glucose, adrenocorticotropic hormone (ACTH), 3-methylhistidine (3-MH), insulin, cortisol, free fatty acid (FFA), creatinine (Cr), and ketone body levels were measured pre-anesthesia, 1 h post-glucose infusion, at the end of surgery, and on the following morning. Results: A total of 31 patients (aged 75–85) were included (0G, n = 16; LG, n = 15). ACTH levels during anesthesia decreased significantly in both groups. In the LG group, glucose levels increased significantly after glucose loading but hyperglycemia was not observed. During surgery, ketone bodies and FFA were significantly lower in the LG group than the 0G group. There were no significant differences in insulin, Cr, 3-MH, and 3-MH/Cr between the two groups. Conclusion: Remifentanil-induced anesthesia inhibited surgical stress response in elderly patients. Intraoperative low-dose glucose infusion attenuated catabolism of fat without inducing hyperglycemia

Isoflurane actions via the mKCa channel

Purpose : Activation of the mitochondrial calcium-activated potassium (mKCa) channel reportedly confers resistance to myocardial ischemic stress. However, the role of the mKCa channel in postconditioning induced by volatile anesthetic remains unclear. Methods :Male Japanese white rabbits underwent coronary artery occlusion for 30 min followed by reperfusion for 3 h. Volatile anesthetic, isoflurane, was administered at 3min prior to reperfusion for 5 min. Rabbits were injected with the mKCa channel blocker, iberiotoxin, or the mKCa channel opener, NS1619, at 8 min prior to reperfusion. Myocardial infarct size and the area at risk (AAR) were measured at the end of the experiment. Results : Isoflurane significantly reduced infarct size (23.0±9.8% of the AAR, P<0.05) compared with the control (44.0±9.1%). Iberiotoxin abolished the cardioprotective impact of isoflurane (43.0±11.6%), while iberiotoxin alone exerted no effect on infarct size (45.0±9.5%). NS1619 and isoflurane/ NS1619 both significantly reduced infarct size (21.0±10.3% and 19.0±8.8%, respectively, P<0.05 vs control group), but isoflurane/NS1619 showed no additional benefits compared with isoflurane alone. Conclusion : These results indicate that activation of the mKCa channel contribute isoflurane-induced postconditioning

Live lecture versus video podcast in undergraduate medical education: A randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Information technology is finding an increasing role in the training of medical students. We compared information recall and student experience and preference after live lectures and video podcasts in undergraduate medical education.</p> <p>Methods</p> <p>We performed a crossover randomised controlled trial. 100 students were randomised to live lecture or video podcast for one clinical topic. Live lectures were given by the same instructor as the narrator of the video podcasts. The video podcasts comprised Powerpoint™ slides narrated using the same script as the lecture. They were then switched to the other group for a second clinical topic. Knowledge was assessed using multiple choice questions and qualitative information was collected using a questionnaire.</p> <p>Results</p> <p>No significant difference was found on multiple choice questioning immediately after the session. The subjects enjoyed the convenience of the video podcast and the ability to stop, review and repeat it, but found it less engaging as a teaching method. They expressed a clear preference for the live lecture format.</p> <p>Conclusions</p> <p>We suggest that video podcasts are not ready to replace traditional teaching methods, but may have an important role in reinforcing learning and aiding revision.</p