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This paper describes a user-friendly power simulation program for teaching power system operations and control. The motivation for the development of the program is to provide students with a simple and useable tool for gaining an intuitive feel for power system operations. This Microsoft Windows[TM] based program simulates power system operation over a specified time period (of typically several hours to a day). Students dynamically interact with the simulated system through various windows, including a one-line display. The use of data files and option windows allows the program to simulate a wide variety of different power systems and operating problems. Efficient programming results in a modest program size of just 450k, allowing for easy distribution to students.

A new-generation laboratory for electric power is described. The design and results in operation are discussed. Examples of experiments are presented. The laboratory provides safe, modern, concept-intensive study of power devices and systems. Experience with the facility demonstrates that it is possible to create an integrated approach to the broad area of power devices, systems, and their control--without compromise of the laboratory experience.

Field-collected males of the scorpionfly Panorpa vulgaris (Insecta: Mecoptera: Panorpidae) were separated on the basis of whether or not they could produce salivary nuptial food during matings in the laboratory. Adult males must feed to secret salivary nuptial gifts. Males who could secrete saliva during mating were designated nutritionally |high' and males who could not were designated nutritionally |low'. This designation may reflect differences in the ability of the two types of males to compete with conspecifics for food in the habitat. Nutritionally high and nutritionally low fathers were paired haphazardly with virgin mates, all of whom were full siblings. The adult sons of nutritionally high fathers won significantly more fights and mates than the sons of nutritionally low fathers when the two were placed in competition for food. The adult daughters of nutritionally high fathers won significantly more fights in competition with adult daughters of nutritionally low fathers. These sire effects on offspring performance were not confounded by body size differences of contestants. Bilateral symmetry is heritable, differs significantly between the two sire categories and between the offspring of the sire categories, and nutritionally low sires and their offspring are more bilaterally asymmetrical. The genetic paternal effects on offspring fitness components may give rise to female choice based on genetic quality of potential sires.

Abstract Background Portal hypertension and cardiac alterations previously described as "cirrhotic cardiomyopathy" are known complications of end stage liver disease (ELD). Cardiac failure contributes to morbidity and mortality, particularly after liver transplantation and transjugular intrahepatic portosystemic shunt (TIPS). We sought to identify myocardial tissue characterization and evaluate cardiovascular magnetic resonance (CMR) for diagnosis of cardiac impairment. Results Twenty ELD patients underwent CMR for morphological, functional and tissue characterization by late gadolinium enhancement (LGE). Based on extent of LGE, patients were dichotomized into high and low LGE groups and analyzed regarding liver, cardiocirculatory and renal functions. CMR demonstrated hyperdynamic left ventricular function and a patchy pattern of LGE of the myocardium to a variable extent (range 2-62%) in all patients. There were no significant differences in Model for End-Stage Liver Disease (MELD), Child-Pugh score or the left ventricular ejection fraction between high and low LGE groups. QTc-interval was prolonged in 25% of the patients. E/A ratio was at the upper limit of norm; no difference between groups. Patients showing high LGE had a higher CI (p < 0.05). Biomarkers of myocardial stress were elevated. While NT-proBNP and c-Troponin-T showed no differences, PLGF and sFLT1 were lower in the high LGE group. Conclusion CMR shows myocardial involvement in patients with ELD resembling appearance of myocarditis. The hyperdynamic circulation in portal hypertension may be an important factor. Larger prospective trials are warranted to confirm the association with severity and outcome of liver disease and to test the predictive power of CMR for patients listed for liver transplantation.

Abstract Background Decompensated cirrhosis is associated with a poor prognosis and liver transplantation provides the only curative treatment option with excellent long-term results. The relative shortage of organ donors renders the allocation algorithms of organs essential. The optimal strategy based on scoring systems and/or waiting time is still under debate. Methods Data sets of 268 consecutive patients listed for single-organ liver transplantation for nonfulminant liver disease between 2003 and 2005 were included into the study. The Model for End-Stage Liver Disease (MELD) and Child-Turcotte-Pugh (CTP) scores of all patients at the time of listing were used for calculation. The predictive ability not only for mortality on the waiting list but also for the need for withdrawal from the waiting list was calculated for both scores. The Mann-Whitney-U Test was used for the univariate analysis and the AUC-Model for discrimination of the scores. Results In the univariate analysis comparing patients who are still on the waiting list and patients who died or were removed from the waiting list due to poor conditions, the serum albumin, bilirubin INR, and CTP and MELD scores as well as the presence of ascites and encephalopathy were significantly different between the groups (p < 0.05), whereas serum creatinine and urea showed no difference. Comparing the predictive abilities of CTP and MELD scores, the best discrimination between patients still alive on the waiting list and patients who died on or were removed from the waiting list was achieved at a CTP score of ≥9 and a MELD score of ≥14.4. The sensitivity and specificity to identify mortality or severe deterioration for CTP was 69.0% and 70.5%, respectively; for MELD, it was 62.1% and 72.7%, respectively. This result was supported by the AUC analysis showing a strong trend for superiority of CTP over MELD scores (AUROC 0.73 and 0.68, resp.; p = 0.091). Conclusion The long term prediction of mortality or removal from waiting list in patients awaiting liver transplantation might be better assessed by the CTP score than the MELD score. This might have implications for the development of new improved scoring systems.