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Selected AbstractsSpatial Distribution and Frequency Dependence of Arrhythmogenic Vagal Effects in Canine AtriaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2000OLEG F. SHARIFOV Ph.D. Arrhythmogenic Vagal Effects in Dog Atria. introduction: Prior studies in isolated canine atria demonstrated that acetylcholine-induced reentrant atrial fibrillation (AF) was triggered by multifocal activity in the area of normal impulse origin (sinus node-crista terminalis). The aim of this study was to investigate the activation sequence in AF induced by vagal stimulation (VS) in intact dog hearts. Methods and Results: VS (10 to 50 Hz, 1 msec, 15 V, 5-sec trains) induced single or multiple atrial premature depolarizations (APDs), and/or AF in 8 of 10 open chest dogs. Occurrence of APDs and AF increased with increasing VS intensity. Epicardial mapping (254 unipolar electrodes) of both atria showed that APDs as a rule emerged from ectopic sites, often from the right atrial appendage. Activation mapping of the first 10 cycles of AF showed that only a small number (<3 to 4) of unstable reentrant circuits were possible at the same moment. Moreover, most sustained VS-induced AFs were accounted for by a single leading stable reentrant circuit that activated the remainder of the atria. Conclusion: (1) Occurrence of vagally induced APDs and AF increases with increasing frequency of VS. (2) VS-induced focal ectopic APDs are widely distributed over the atria. (3) A single APD can be sufficient for initiation of reentrant AF. (4) Despite its high rate of sustained AF, it may be maintained by single stable reentrant circuit. (5) The atrial septum can play an important role in both the initiation and the maintenance of VS-induced AF. [source] Effect of Molecular Weight on Photoinduced Birefringence in a Chiral Liquid Crystalline Azodye PolymerMACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2006Mikhail Kozlovsky Abstract Summary: The evolution of the photoinduced birefringence in thin films of narrow polymer fractions is studied and compared with the behavior of the non-fractionated polymer. The ,nind value decreases by increasing the degree of polymerization () within the oligomeric range but becomes independent of molecular weight starting from a of ,70. Thermal pretreatment of the films results in higher photoinduced birefringence. The films show good stability of the photorecording. Birefringence induced after 10 min, ,nind(600) and its growth rate at the same moment versus molecular weight. [source] Why evidence-based practice now?: a polemic1NURSING INQUIRY, Issue 3 2003Kim Walker Evidence-based practice (EBP) first appeared on the healthcare horizon just over a decade ago. In 2003 its presence has intensified and extended beyond its initial relation to medicine embracing as it does now, nursing and the allied health disciplines. In this paper, I contend that its appearance and subsequent growth and development are the effects of potent ,regimes of truth', four of which bear the names: positivism, empiricism, pragmatism and economic rationalism. My aim is to show how EBP generates the controversy it does because its nature and methods are inextricably interwoven with the way it has become politicised and professionalised. This exegesis is an attempt to outline how the combined effects of the four forms of rationality mentioned above allow for both the methods and objectives of EBP to be constructed as they are, while at the same moment producing the particular effects of knowledge and power in terms of who sells and who buys the idea of EBP in the culture of contemporary healthcare. [source] Making the Monkey: How the Togean Macaque Went from "New Form" to "Endemic Species" in Indonesians' Conservation BiologyCULTURAL ANTHROPOLOGY, Issue 4 2004Celia Lowe Indonesian scientists inhabit a postcolonial world where they are both elite (within the nation) and subaltern (within transnational science) at precisely the same moments. A study of science that is neither "ethno" nor "Euro" requires a postcolonial refiguration not only of how science's matter is made but of where and by whom. In the 1990s, the Togean macaque (Macaca togeanus) was proposed as a new species endemic to the Togean Islands, the proposed site of a new conservation area in Central Sulawesi, Indonesia. In the scientific production of biodiverse nature, Indonesian primatologists identified the monkey first as a "new form," then as a "dubious name," and subsequently, as an "endemic species." Throughout these acts of making, unmaking, and remaking the monkey, its unique and endemic status was important for developing Indonesian conservation biology, attracting foreign donors, and enlisting government and public interest in Togean Island nature, even as forms of nature important to Togean peoples were overwritten in this process. [source] | ||||||||||