Cardiac Rate and Rhythm

Cardiac Rate and Rhythm
Author: L.N. Bouman
Publisher: Springer Science & Business Media
Total Pages: 675
Release: 2012-12-06
Genre: Medical
ISBN: 940097535X

In the denervated state the mammalian heart, both in vivo and in vitro, is excited at very regular intervals, the coefficient of variance of the interbeat intervals not exceeding 2%. The pacemaker that is the source of this regular ex citation is localised normally within the sinus node (" sino-atrial node " node of Keith and Flack), a most intriguing small piece of tissue in the caval corner of the right atrium. A small portion of this node containing a group of probably only a few thousands of cells fires spontaneously, that means without any exter nal influence to trigger their activity. The so called pacemaker cells do this by letting their membrane potential fall to the level where an action potential will start which subsequently activates surrounding cells to fire an action po tential. The first question which is tackled in this book is which processes underly this spontaneous diastolic depolarization. This is discussed in section I, concerning the fundamental properties of pacemaker cells with special refer ence to ionic membrane currents. Although views still quite differ about the exact nature of the membrane processes that cause the automatic pacemaker dis charge there is agreement that diastolic depolarization is brought about by the interaction of a number of ionic current systems, including both inward and out ward going currents.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports
Author:
Publisher:
Total Pages: 730
Release: 1980
Genre: Aeronautics
ISBN:

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

The Blue Light Syndrome

The Blue Light Syndrome
Author: H. Senger
Publisher: Springer Science & Business Media
Total Pages: 669
Release: 2012-12-06
Genre: Science
ISBN: 3642676480

Investigations on the specific effects of blue light on plants began some fifty years ago. In re cent years the growing awareness of blue-light-in duced phenomena in plants, microorganisms, and animals has accelerat ed and expanded this research into an ever-increasing variety of blue light effects in biological systems. In 1977, J .A. Schiff and W .R. Briggs proposed a specific meeting to present and summarize the various blue-light effects and to discuss their mechanisms and possible photoreceptors. In view of the variety of re sponses and the range of organisms affected by blue light the term Blue Light Syndrome seemed to be the only appropriate one for the meeting. With the help of the International Advisory Committee (W.R. Briggs, Stanford; J. Gressel, Rehovot; W. Kowallik, Bielefeld; S. Miyachi, To kyo; W. Rau, Munich, and J.A. Schiff, Waltham), and the very generous financial support provided by the Deutsche Forschungsgemeinschaft as well as by the Bundesministerium fur Forschung und Technologie, the Kultusminister des Landes Hessen, and the Philipps-Universitat Marburg, the "International Conference on the Effect of Blue Light in Plants and Microorganisms" was held in July 1979 in the Philipps-Universitat Mar burg."

Resistant Practices in Communities of Sound

Resistant Practices in Communities of Sound
Author: Deanna Fong
Publisher: McGill-Queen's Press - MQUP
Total Pages: 237
Release: 2024-07-15
Genre: Literary Criticism
ISBN: 0228021758

Print – and by extension, visuality – has historically dominated the literary, artistic, and academic spheres in Canada; however, scholars and artists have become increasingly attuned to the creative and scholarly opportunities offered by paying attention to sound. Resistant Practices in Communities of Sound turns to a particular opportunity, interrogating the ways that sonic practices act as forms of aesthetic and political dissent. Chapters explore, on the one hand, critical methods of engaging with sound – particularly bodies of literary and artistic work in their specific materiality as read, recited, performed, mediated, archived, and remixed objects; on the other hand, they also engage with creative practices that mobilize sound as a political aesthetic, taking on questions of identity, racialization, ability, mobility, and surveillance. Divided into nine pairings that bring together works originating in oral/aural forms with works originating in writing, the book explores the creative and critical output of leading sonic practitioners. It showcases diverse approaches to the equally complex formations of sound, resistance, and community, bridging the too-often separate worlds of the practical and the academic in generative, resonant dialogue. Combining the oral and the written, the creative and the critical, and the mediated and the live, Resistant Practices in Communities of Sound asks us to attune ourselves as listeners as well as readers.