New Concept of PLC Modems: Multi-Carrier System for Frequency Selective Slow-Fading Channels Based on Layered SCCC Turbocodes

The article introduces a novel concept of a PLC modem as a complement to the existing G3 and PRIME standards for communications using medium- or high-voltage overhead or cable lines. The proposed concept is based on the fact that the levels of impulse noise and frequency selectivity are lower on high-voltage lines than on low-voltage ones. Also, the demands for “cost-effective” circuitry design are not so crucial as in the case of modems for low-voltage level. In contract to these positive conditions, however, there is the need to overcome much longer distances and to take into account low SNR on the receiving side. With respect to the listed reasons, our concept makes use of MCM, instead of OFDM. The assumption of low SNR is compensated through the use of an efficient channel coding based on a serially concatenated turbo code. In addition, MCM offers lower latency and PAPR compared to OFDM. Therefore, when using MCM, it is possible to excite the line with higher power. The proposed concept has been verified during experimental transmission of testing data over a real, 5 km long, 22kV overhead line

Results of Immediate Discharge From Postanesthesia Care Unit to Home After Laparoscopic Appendectomy for Acute Nonperforated Appendicitis.

BACKGROUND: This study examines the efficacy and safety of immediate discharge from the postanesthesia care unit after laparoscopic appendectomy for patients with acute nonperforated appendicitis. METHODS: A retrospective study of 114 laparoscopic appendectomy cases was performed. Seventy-four patients met inclusion criteria of having uncomplicated acute appendicitis. Patient demographics, operative times, length of postoperative stay, and complication rates were analyzed. RESULTS: Only 3 of the 74 patients failed to be discharged immediately. Mean postoperative discharge time was 130.5 minutes with 86% of patients leaving within 3 hours. Delay in voiding was the most common cause of stays longer than 4 hours. Six of the 74 patients (8%) returned to the emergency room without need for readmission. There were no complications associated with the early discharge. CONCLUSIONS: Immediate discharge from the postanesthesia care unit for patients with acute nonperforated appendicitis appears safe and effective in the community hospital setting