196,263 research outputs found
Respiratory pattern in awake rats: Effects of motor activity and of alerting stimuli
No full textOur aim was to assess the impact of motor activity and of arousing stimuli on respiratory rate in the awake rats. The study was performed in male adult Sprague–Dawley (SD, n = 5) and Hooded Wistar (HW, n = 5) rats instrumented for ECG telemetry. Respiratory rate was recorded using whole-body plethysmograph, with a piezoelectric sensor attached for the simultaneous assessment of motor activity. All motor activity was found to be associated with an immediate increase in respiratory rate that remained elevated for the whole duration of movement; this was reflected by: i) bimodal distribution of respiratory intervals (modes for slow peak: 336 ± 19 and 532 ± 80 ms for HW and SD, p < 0.05; modes for fast peak 128 ± 6 and 132 ± 7 ms for HW and SD, NS); and ii) a tight correlation between total movement time and total time of tachypnoea, with an R2 ranging 0.96–0.99 (n = 10, p < 0001). The extent of motor-related tachypnoea was significantly correlated with the intensity of associated movement. Mild alerting stimuli produced stereotyped tachypnoeic responses, without affecting heart rate: tapping the chamber raised respiratory rate from 117 ± 7 to 430 ± 15 cpm; sudden side move — from 134 ± 13 to 487 ± 16 cpm, and turning on lights — from 136 ± 12 to 507 ± 14 cpm (n = 10; p < 0.01 for all; no inter-strain differences). We conclude that: i) sniffing is an integral part of the generalized arousal response and does not depend on the modality of sensory stimuli; ii) tachypnoea is a sensitive index of arousal; and iii) respiratory rate is tightly correlated with motor activity.Muammar M. Kabir, Mirza I. Beig, Mathias Baumert, Mimosa Trombini, Francesca Mastorci, Andrea Sgoifo, Frederick R. Walker, Trevor A. Day and Eugene Nalivaiko1. Introduction
2. Methods
2.1. Ethical approval and preliminary surgery
2.2. Recordings of respiration and gross motor activity
2.3. Experimental protocol
2.4. Data acquisition and analysis
3. Results
3.1. Respiration during basal conditions — qualitative observation
3.2. Assessment of respiratory indices and motor indices
3.3. Relationship between motor activity and respiratory pattern
3.4. Heart rate during basal conditions and its association with motor activity
3.5. Cardiac and respiratory responses to alerting stimuli
4. Discussion
4.1. Respiratory rate in spontaneously behaving rats
4.2. Dissociation between respiratory and cardiac responses to alerting stimuli
4.3. Neural mechanisms underlying motor-related and arousal-induced tachypnoea
4.4. Inter-strain differences
4.5. Physiological role of tachypnoeic responses
5. Conclusions
Reference
Cardiorespiratory coordination in rats is influenced by autonomic blockade
No full textAutonomic disturbance creates changes in the modulation of heart rate. In this study we analyzed the influence of sympathetic and vagal blockade on the interaction between cardiac and respiratory rhythms. In seven anaesthetized rats, electrocardiogram (ECG), and respiratory rate were recorded continuously before and after autonomic blockade with either methyl-scopolamine or atenolol. For the assessment of cardiorespiratory coordination, we analyzed the phase locking between heart rate, computed from the R-R intervals of body surface ECG, and respiratory rate, computed from impedance changes, using Hilbert transform. The procedure was carried out for different m:n coordination ratios where, m, is the number of heart beats and n, is the number of respiratory cycles. The changes in percentage of synchronization and duration of synchronized epochs before and after injection were assessed with one-way ANOVA. Sympathetic blockade with atenolol caused an increase (baseline: 0.49 } 0.03s vs. blockade: 0.54 } 0.06s) and vagal blockade with methylscopolamine caused a decrease (baseline: 0.49 } 0.03s vs. blockade: 0.45 } 0.08s) in the duration of synchronized epochs. Neither the overall percentage of synchronized epochs, (baseline: 10.76 } 3.5% vs. blockade 9.44 } 4.3%), nor the average locking ratio, 3:1, was significantly affected by autonomic blockade. In conclusion, the phase-locking between heart rhythm and respiration is modulated by both vagal and sympathetic efferences, in the opposite directionsM.M. Kabir, M.I. Beig, E. Nalivaiko, D. Abbott and M. Baumer
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
Blockade of 5-HT2A receptors suppresses hyperthermic but not cardiovascular responses to psychosocial stress in rats
No full textCopyright © 2009 IBRO Published by Elsevier Ltd.The aim of this study was to determine whether 5-HT2A receptors mediate cardiovascular and thermogenic responses to acute psychological stresses. For this purpose, adult male Wistar hooded rats instrumented for telemetric recordings of either electrocardiogram (ECG) (n=12) or arterial pressure (n=12) were subjected, on different days, to four 15-min episodes of social defeat. Prior to stress, animals received s.c. injection of the selective 5-HT2A receptor antagonist SR-46349B (trans-4-((3Z)3-[(2-dimethylaminoethyl)oxyimino]-3-(2-fluorophenyl)propen-1-yl)-phenol, hemifumarate) (at doses of 0.3, 1.0 and 3.0 mg/kg) or vehicle. The drug had no effect on basal heart rate or heart rate variability indexes, arterial pressure, and core body temperature. Social defeat elicited significant and substantial tachycardic (347+/-7 to 500+/-7 bpm), pressor (77+/-4 to 97+/-4 mm Hg) and hyperthermic (37.0+/-0.3 to 38.5+/-0.1 degrees C) responses. Blockade of 5-HT2A receptors, at all doses of the antagonist, completely prevented stress-induced hyperthermia. In contrast, stress-induced cardiovascular responses were not affected by the blockade (except small reduction of tachycardia by the highest dose of the drug). We conclude that in rats, 5-HT2A receptors mediate stress-induced hyperthermic responses, but are not involved in the genesis of stress-induced rises in heart rate or arterial pressure, and do not participate in cardiovascular control at rest.M.I. Beig, M. Baumert, F.R. Walker, T.A. Day and E. Nalivaikohttp://www.elsevier.com/wps/find/journaldescription.cws_home/468/description#descriptio
Ex elega[n]tissimis Fausti An//drelini amoru[m] libris quattu//or selecti versus : cu[m] nonnullis alioru[m] poetaru[m]// carminib[us] puero[rum] i[n]stitutio[n]i sane qua[m] idoneis
No full textIn FrakturMit Beig. von Hermann von dem Busche, Johann Murmellius, Luigi Bigi Pittorio, Panfilo Sassi und Baptista GK 4.766
Isoflurance increases cardiorespiratory coordination in rats
No full text©2008 COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.Anesthetics such as isoflurane adversely affect heart rate. In this study we analysed the interaction between heart rhythm and respiration at different concentrations of isoflurane and ventilation rates. In two rats, the electrocardiogram (ECG) and respiratory signals were recorded under the influence of isoflurane. For the assessment of cardiorespiratory coordination, we analysed the phase locking between heart rate, computed from the R-R intervals of body surface ECG, and respiratory rate, computed from impedance changes, using Hilbert transform. The changes in heart rate, percentage of synchronization and duration of synchronized epochs at different isoflurane concentrations and ventilation rates were assessed using linear regression model. From this study it appears that the amount of phase locking between cardiac and respiratory rates increases with the increase in concentration of isoflurane. Heart rate and duration of synchronized epochs increased significantly with the increase in the level of isoflurane concentration while respiratory rate was not significantly affected. Cardiorespiratory coordination also showed a considerable increase at the ventilation rates of 50- 55 cpm in both the rats, suggesting that the phase-locking between the cardiac and respiratory oscillators can be increased by breathing at a particular respiratory frequency.Muammar M. Kabir, Mirza I. Beig, Eugene Nalivaiko, Derek Abbott and Mathias Baumer
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