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Selected AbstractsPractical Seakeeping Performance Measures for High Speed Displacement VesselsNAVAL ENGINEERS JOURNAL, Issue 4 2006Dr. Kadir Sariöz The seakeeping performance of high-speed displacement vessels is generally assessed, in a probabilistic manner, by using criteria-based measures of merit. Given a set of seakeeping criteria, these measures, such as the Percentage Time of Operation (PTO) and the Seakeeping Performance Index (SPI), could provide an assessment of the operability of the vessel in a specified sea area. The criteria-based measures are based upon the probability of exceeding specified ship motions in a sea environment particular to the vessel's mission. Given the operational area of the vessel, the percentage of time the vessel operates in a particular sea state can be determined by comparing the predicted motions to the motion limiting criteria. However, because the seakeeping criteria are used in a pass/fail manner, the criteria-based procedures give no credit for reducing motions that do not exceed criteria. This may result in misleading conclusions when the relative seakeeping performance of alternative design concepts is compared. It is shown that criteria-free measures, based upon a normalized summation of critical ship responses for a range of ship speeds and wave headings in a specified sea area, may produce more reliable results when the seakeeping performance of alternative designs are compared. This approach also has the clear advantage of not requiring a set of seakeeping criteria, which is subjective in nature. To demonstrate the effect of typical measures of merit on seakeeping performance assessment, six typical high-speed displacement vessel forms are considered in a comparative analysis. Both the criteria-free and criteria-based measures of merit are employed to compare the seakeeping performance of selected vessels. The results indicate that the choice of seakeeping performance measure of merit depends on the nature of seakeeping analysis and criteria-free measures offer a simple, practical, and realistic assessment in comparative seakeeeping studies. [source] Processes controlling rapid temperature variations on rock surfaces,EARTH SURFACE PROCESSES AND LANDFORMS, Issue 5 2010Jamie L. Molaro Abstract In arid environments, thermal oscillations are an important source of rock weathering. Measurements of temperature have been made on the surface of rocks in a desert environment at a sampling interval of 0·375,s, with simultaneous measurements of wind speed, air temperature, and incoming shortwave radiation. Over timescales of hours, the temperature of the rock surface was determined primarily by shortwave radiation and air temperature, while rapid temperature variations, high dT/dt, at intervals of seconds or less, were determined by wind speed. The maximum values of temperature change and time spent above 2°C,min,1 increased at high measurement rates and were much higher than previously reported. The maximum recorded value of dT/dt was 137°C,min,1 and the average percentage time spent above 2°C,min,1 was ,70 ± 13%. Maximum values of dT/dt did not correlate with the maximum values of time spent above 2°C,min,1. Simultaneous measurements of two thermocouples 5·5,cm apart on a single rock surface had similar temperature and dT/dt values, but were not correlated at sampling intervals of less than 10,s. It is suggested that this is resulting from rapid fluctuations due to small spatial and timescale wind effects that are averaged out when data is taken at longer sampling intervals, ,10,s or greater. Published in 2010 by John Wiley & Sons, Ltd. [source] Clinical trial: Inhibitory effect of revaprazan on gastric acid secretion in healthy male subjectsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2010Hyung-Keun Kim Abstract Background and Aim:, Revaprazan is a novel acid pump antagonist. The aim of this study was to investigate the inhibitory effect of revaprazan on gastric acid secretion in healthy male subjects. Methods:, In a double-blind, three-way cross-over study, 30 healthy male volunteers were randomized to 100, 150 or 200 mg of oral revaprazan daily for 7 days. Serum gastrin concentration was measured, and 24-h intragastric pH was recorded at baseline and on days 1 and 7 of each administration period. Serial blood samples were processed for pharmacokinetics. Results:, Median intragastric pH over 24 h and mean percentage time that pH was > 4 increased in a dose-dependent manner and were significantly higher on days 1 and 7 compared with baseline in all groups (P < 0.05). The antisecretory effect of revaprazan was rapid and nearly maximal on day 1 in all groups. Serum gastrin levels were rapidly normalized by 100 and 150 mg/day of revaprazan on days 1 and 7, but were significantly higher in the 200 mg/day revaprazan group. The pharmacokinetic effect was rapidly absorbed and eliminated on days 1 and 7 in all groups. Conclusions:, Revaprazan rapidly and effectively inhibits gastric acid secretion in healthy male subjects. Therefore, revaprazan can be used as an effective drug for acid-related disease. [source] Methods for calculating activity budgets compared: a case study using orangutansAMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2009Mark E. Harrison Abstract The results of comparisons of behavioral data between individuals, age,sex classes, seasons, sites and possibly even species may depend on sample size and the computational method used. To establish whether these are valid concerns, we compared results for percentage time spent feeding on major food types (fruit, leaves, flowers, invertebrates, bark, pith and other) for two orangutan populations in Sabangau (24 months) and Tuanan (29 months), Indonesian Borneo. Both the minimum follow limit included in analyses and the computational method used produced small, but statistically significant, differences in the results obtained, and the differences were more common for food types eaten less frequently. In addition, using different computational methods produced more significant differences than did including different minimum follow lengths in analyses. The computational method used also influenced the results of tests for differences in diet composition between age,sex classes. Thus, the method used can influence the results obtained and, hence, it is important to state explicitly the minimum follow limit included and computational method used to compile averages, and to ensure standardization in methods when comparing data between age,sex classes, time periods, field sites or species. Am. J. Primatol. 71:353,358, 2009. © 2008 Wiley-Liss, Inc. [source] Continuous Venovenous Renal Replacement Therapy With a Pulsatile Tubular Blood Pump: Analysis of Efficacy ParametersARTIFICIAL ORGANS, Issue 1 2006Jesús López-Herce Abstract:, A three-valve pulsatile tubular pump was used in 10 pigs weighing 9.9 ± 0.3 kg, connected to a neonatal hemofiltration (HF) circuit to analyze the parameters to determine the ultrafiltration effectiveness for venovenous continuous renal replacement therapy. Forty 30-min periods were studied to analyze the influence of the catheter diameter, purification technique (HF or hemodiafiltration), pump pulsation frequency, percentage time in diastole, percentage time in diastole in which the postpump valve was closed, and percentage time in systole in which the postfilter valve was closed, on ultrafiltrate volume and blood flow through the filter. A higher ultrafiltrate flow was achieved with a frequency of 60 bpm than with 30 bpm, a diastolic time of 65% of the total cycle versus 50%, and a blood flow of greater than 20 mL/min versus less than 20 mL/min. The ultrafiltrate flow increases in relation to the blood flow, the frequency of the pump, and the diastolic time. [source] Oesophageal and gastric bile exposure after gastroduodenal surgery with Henley's interposition or a Roux-en-Y loopBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2004J.-Y. Mabrut Background: The degree which the various reconstruction techniques prevent bile reflux after gastroduodenal surgery has been poorly studied. Methods: Bile exposure in the intestinal tract just proximal to the jejunal loop was measured with the Bilitec 2000® device for 24 h after gastroduodenal surgery in three groups of patients. Group 1 comprised 24 patients with a 60-cm Henley's loop after total gastrectomy. Group 2 included 31 patients with a 60-cm Roux-en- loop after total (22 patients) or subtotal (nine) gastrectomy. Group 3 contained 21 patients with a 60-cm Roux-en- loop anastomosed to the proximal duodenum as part of a duodenal switch operation for pathological transpyloric duodenogastric reflux. Bile exposure, measured as the percentage time with bile absorbance greater than 0·25, was classified as nil, within the range of a control population of healthy subjects, or pathological (above the 95th percentile for the control population). Reflux symptoms were scored and all patients had upper gastrointestinal endoscopy. Results: Bile was detected in the intestine proximal to the loop in none of 24 patients in group 1, eight of 31 in group 2 and 12 of 21 in group 3 (P < 0·001). The mean reflux symptom score increased with the degree of bile exposure, and the proportion of patients with oesophagitis or gastritis correlated well with the extent of bile exposure (P < 0·001). Conclusion: A long Henley's loop was more effective in preventing bile reflux than a long Roux-en- loop. Bilitec® data correlated well with the severity of reflux symptoms and the presence of mucosal lesions. Copyright © 2004 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Electronically monitored cowpea aphid feeding behavior on resistant and susceptible lupinsENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2001Geoffrey W. Zehnder Abstract The feeding behavior of cowpea aphid, Aphis craccivora Koch (Homoptera: Aphididae) was examined on seedlings of narrow leafed lupin, Lupinus angustifolius L., and yellow lupin, L. luteus L., using electronic monitoring of insect feeding behavior (EMIF). Aphid feeding behavior was first compared between resistant (cv. Kalya) and susceptible (cv. Tallerack) varieties of narrow-leafed lupin. Aphids spent significantly more time in non- penetration and stylet pathway activities, and significantly less time in the sieve element phase on Kalya than on Tallerack, suggesting that feeding deterrence is an important component of aphid resistance in Kalya. Aphid feeding on a susceptible yellow lupin variety (cv. Wodjil) was then compared with that on two resistant lines, one (Teo) with high and the other (94D024-1) with low seed alkaloid content. There were no consistent differences in aphid feeding behavior between Wodjil and Teo. Total, mean and percentage sieve element phase times were significantly lower, and total and percentage times in non-phloem phase were greater on 94D024-1 than on Wodjil, suggesting the possibility of phloem-based deterrence in 94D024-1. [source] | |||||||||||||