7,337 research outputs found
Wind loads on ground-based telescopes
One of the factors that can influence the performance of large optical telescopes is the vibration of the telescope structure due to unsteady wind inside the telescope enclosure. Estimating the resulting degradation in image quality has been difficult because of the relatively poor understanding of the flow characteristics. Significant progress has recently been made, informed by measurements in existing observatories, wind-tunnel tests, and computational fluid dynamic analyses. We combine the information from these sources to summarize the relevant wind characteristics and enable a model of the dynamic wind loads on a telescope structure within an enclosure. The amplitude, temporal spectrum, and spatial distribution of wind disturbances are defined as a function of relevant design parameters, providing a significant improvement in our understanding of an important design issue
Mission Planner Algorithm for Urban Air Mobility Initial Performance Characterization
In this paper, an initial characterization was performed of the Mission Planner algorithm developed by NASA for Urban Air Mobility (UAM) operations research. The algorithm plans conflict-free trajectories for flights to support a given set of UAM passenger trips. The UAM trips are planned in an on-demand, first-come, first-served manner, such that any given trip is subject to the constraints imposed by previously planned trips. For this analysis, the mission planning algorithm considered only the trajectory constraints from previously-planned trips in one test condition and added vertiport constraints for the second test condition. The conflict and constraint resolution strategies used by the Mission Planner were characterized by their percentage contribution to planning iterations, their percentage effectiveness in those iterations, and their contributions to the departure delay applied to each UAM trips flight. With the exception of the climb and descent vertical speed strategies, most strategies showed reasonable or good performance in all test scenarios. In the test condition with vertipad constraints enabled, both the total number of iterations executed, and the number of flights that required planning iterations, was reduced for all scenarios. This was the result of the natural conditioning of the traffic achieved with scheduling and the additional information available to the Mission Planner from the vertiport scheduler. The next steps for this work will include improvements to the mission planning strategies and analyses with additional constraints and under other demand scenarios
General anesthesia does not have persistent effects on attention in rodents
Background: Studies in animals have shown that general anesthesia can cause persistent spatial memory impairment, but the influence of anesthetics on other cognitive functions is unclear. This study tested whether exposure to general anesthesia without surgery caused a persistent deficit in attention in rodents.Methods: To evaluate whether anesthesia has persistent effects on attention, rats were randomized to three groups. Group A was exposed for 2 h to isoflurane anesthesia, and tested the following seven days for attentional deficits. Group B was used as a control and received room air before attentional testing. Since there is some evidence that a subanesthetic dose of ketamine can improve cognition and reduce disorders of attention after surgery, rats in group C were exposed to isoflurane anesthesia in combination with a ketamine injection before cognitive assessment. Attention was measured in rats using the 5-Choice Serial Reaction Time Task, for which animals were trained to respond with a nose poke on a touchscreen to a brief, unpredictable visual stimulus in one of five possible grid locations to receive a food reward. Attention was analyzed as % accuracy, % omission, and premature responses.Results: Evaluating acute attention by comparing baseline values with data from the day after intervention did not reveal any differences in attentional measurements. No significant differences were seen in % accuracy, % omission, and premature responses for the three groups tested for 7 consecutive days.Conclusion: These data in healthy rodents suggest that general anesthesia without surgery has no persistent effect on attention and the addition of ketamine does not alter the outcome
The Ursinus Weekly, April 30, 1928
Haverford track team buries Ursinus squad under 101 1/2- 33 1/2 score • Dr. Holmes addresses joint service on patriotism • Ursinus to be scene of county play festival • Junior festivities reign supreme in weekend of dance and drama • Ursinus relay team finishes third at Penn • Shepherd Whitman chosen commencement orator • Grizzly nine home for two games this week • Penn man lectures on preparation of serums • Dinner opening event of busy junior program • All net matches washed out; Temple here Wednesday • Juniors entertain with delightful tea dance • Trophy for court victor in girls\u27 tournament • Debate cancelled • Ursinus seniors to take Carnegie Foundation exam • W.S.G.A. installs new officers • H. - P. group • Represents Ursinus at football meeting • Friday afternoon time set for inter-class meethttps://digitalcommons.ursinus.edu/weekly/2215/thumbnail.jp
The Ursinus Weekly, November 5, 1928
Chapel speakers address students in week of intellectual attainment • Dr. Omwake host to guests at dinner and luncheon • Bears win 6-0 as Muhlenberg falls before superior playing of grizzlies • Non-partisan political rally held last Tuesday • Many events scheduled for coming week-end • The Patsy to be given again by senior class • Newspaper conference held at Haverford, Saturday • Pep dance falls flat as students leave for home • Ursinus lassies bow to Swarthmore maids 9-4 • Grizzlies face Drexel in last home appearance • Women\u27s dorm drive • F. & M. drops baseball as a varsity sport • Candle lighting service held by YWCA • Seniors trim frosh in inter-class hockey game • Dr. Wellburn addresses weekly YMCA meetinghttps://digitalcommons.ursinus.edu/weekly/2163/thumbnail.jp
The Ursinus Weekly, January 7, 1929
Rev. Lentz delivers annual Christmas religious address • Important meeting of literary group, Thursday • Montgomery County dance starts off new year • Bears trim Lafayette 30-27: Grizzlies overcome Leopards\u27 early lead to finish out in front • Christmas dinners mark final event of old year • 1929 Ruby rapidly nearing completion • Grizzlies have two court games this week • Ursinus Debating Club • Rev. Tomkins to talk to joint YM-YWCA • Swarthmore party to observe eclipse • College bulletin released • New order of service • Kermit Black picked on coach Harman\u27s eleven • Takes trip to Florida during Xmas holidays • Football men hold banquet at athletic club • Alumnus writes poem read at Wilson dinner • Y.W.C.A. Xmas party • Mail boxes erected • Choir Xmas concert • Debating issue of Weekly sent to schools • Many colleges in midst of building campaigns • Here is the quiz; test your knowledgehttps://digitalcommons.ursinus.edu/weekly/2171/thumbnail.jp
The Ursinus Weekly, June 4, 1928
Tennis squad closes successful season by trouncing Drexel, 5-1 • Summary of baseball season credits bears with 6 wins, 4 losses • Willard Moyer first in recent Carnegie exams • Seniors hold banquet at Spring Mountain House • Girls\u27 tennis team trims Lebanon Valley lassies, 5-1 • John F. W. Stock given music scholarship • Review of track season; records for local field • Dr. Omwake commencement speaker at Elizabethtown • Men\u27s student council elects new officers • Regular Memorial Day services in chapel • Frosh trim Norristown High School to maintain clean slate • Junior oratoricals Friday • Commencement calendar • Ursinus College to be site of summer conventionshttps://digitalcommons.ursinus.edu/weekly/2220/thumbnail.jp
The Ursinus Weekly, February 18, 1929
Academic exercises of Founders\u27 Day mark sixtieth anniversary • Frosh prove ability as good entertainers • Rev. Asher R. Kepler \u2798 gives monthly lecture • Glee Club on extended trip in coal regions • Entertainment concludes Founders\u27 Day program • Men\u27s negative team wins initial debate • Ursinus loses to Temple and F. & M. in contests played last week • Speeches and good eats feature family dinner • Girls defeat Beaver in exciting game • Girls lose dual debate to Cedar Crest women • Muhlenberg defeats grizzly cubs 19-16 • Rev. Elliott to speak at YM-YW week of prayer • American legion to present annual show • Lorelei dance this Saturday evening • Frosh elect officers for coming semester • Ursinus plays Swarthmore and Delaware this week • Junior class to give movie for 1930 Ruby • Girls install new hall presidents • Booklet on history of Ursinus College issued • Women\u27s Debating Club • Directors order plans for science building • Men\u27s Debating Clubhttps://digitalcommons.ursinus.edu/weekly/2175/thumbnail.jp
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