A correlation between attendance and grades in a first-year psychology class.

Performed a correlational analysis of attendance records and grades in a 1st-yr psychology class. 103 undergraduates were informed that the attendance records would not affect their grades in the course. A positive correlation was found between attendance and final grades in the course. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

IEEE-PES Transmission and Distribution Conference and Exposition Call for Papers

Static network-related system voltage stability margin (VSM) depends on the availability of reactive power to support the transport of real power from sources to sinks. Based on this premise, the total VAr loss is minimized in the unified OPF framework considering real and reactive power controllers, and its effect on VSM is studied. Studies are conducted on a three-bus system, the IEEE 30-bus system, and a 191-bus Indian electric power system, and their results are reported.     

BER performance analysis of a direct conversion receiver

Direct conversion receivers are increasingly popular for use in mobile terminals. This is due to advantages over other architectures such as heterodyne receivers in terms of cost, electrical current, and physical size. However, a direct conversion receiver often generates a DC-offset that has to be taken care of either by suppressing the DC-offset in the radio-frequency part of the receiver, or by taking care of it during baseband processing. A theoretical analysis of the bit error rate (BER) performance in a direct conversion receiver with different levels of DC-offset suppression is presented. Explicit results are presented on how the BER depends on the signal-to-noise ratio (SNR), the signal-to-DC-level, and the choice of pilot symbols both with M-QAM and M-PSK in a slow, flat Rayleigh fading channel. A design rule, which applies to the design of DC-compensation in direct conversion receivers, is also presented     

Propagation of flicker in electric power networks due to windenergy conversions systems

Wind energy conversion systems (WECS) produce fluctuating output power, which may cause voltage fluctuations and flicker. Flicker assessment in networks may be difficult since its evaluation requires long computing time and special procedures to calculate the flicker severity index, Pst. In this paper, a frequency domain method to study flicker propagation is presented. This method is based on propagation of frequency components from WECS output currents throughout the grid. In this way, a fast flicker analysis in a network of any size can be performed. Also, an algorithm for flicker measurement in the frequency domain, which allows Pst calculation, is proposed. Several study cases have been performed, and results have been compared with time domain simulations, showing good agreement between them     

Mechanism analysis of gate-induced drain leakage in off-state n-MOSFET

An analytical expression for both band-to-band and band-trap-band indirect tunnelings is used to study the gate-induced drain leakage (GIDL) current of MOSFETs measured before and after hot-carrier stress. The voltage and temperature dependence of GIDL are characterized. Both results show that interface traps situated near the midgap participate in the conduction of GIDL, and band-trap-band indirect tunneling could be the major mechanism. This is further supported by the fact that the percentage increase in GIDL induced by hot-carrier stress is about the same as the corresponding increase in interface-trap density. On the other hand, under low-field conditions, trap-assisted Poole–Frenkle emission dominates over tunneling for temperatures even well below room temperature.     

Extracorporeal cholelithotripsy, is it still justified as treatment of cholecystolithiasis?

This prospective study evaluates the results of extracorporal shock-wave piezoelectric lithotripsy in 52 patients, 41 with radiolucent and 11 with calcified shell gallstones. The fragmentation rate was above 90% and the complication rate 31% particularly with pains or intolerance to the adjuvant dissolution therapy. At the end of the treatment, seven cholecystectomies were carried out among the 31 patients for who lithotripsy failed. After 18 months, the success rate was 23% and 12 patients only remained stone free. Nowadays, thanks to the new laparoscopic therapy, extracorporal shock-wave lithotripsy is no longer judged appropriate, especially because of its poor cost-effectiveness and high recurrence ratio.