User's manual for interactive LINEAR: A FORTRAN program to derive linear aircraft models

An interactive FORTRAN program that provides the user with a powerful and flexible tool for the linearization of aircraft aerodynamic models is documented in this report. The program LINEAR numerically determines a linear system model using nonlinear equations of motion and a user-supplied linear or nonlinear aerodynamic model. The nonlinear equations of motion used are six-degree-of-freedom equations with stationary atmosphere and flat, nonrotating earth assumptions. The system model determined by LINEAR consists of matrices for both the state and observation equations. The program has been designed to allow easy selection and definition of the state, control, and observation variables to be used in a particular model

Slow Conduction through an Arc of Block: A Basis for Arrhythmia Formation Post-Myocardial Infarction

Introduction The electrophysiologic basis for characteristic rate-dependent, constant-late-coupled (390 + 54 milliseconds) premature ventricular beats (PVBs) present 4–5 days following coronary artery occlusion were examined in 108 anesthetized dogs. Methods and results Fractionated/double potentials were observed in injured zone bipolar and composite electrograms at prolonged sinus cycle lengths (1,296 ± 396 milliseconds). At shorter cycle lengths, conduction of the delayed potential decremented, separating from the initial electrogram by a progressively prolonged isoelectric interval. With sufficient delay of the second potential following an isoelectric interval, a PVB was initiated. Both metastable and stable constant-coupled PVBs were associated with Wenckebach-like patterns of delayed activation following an isoelectric interval. Signal-averaging from the infarct border confirmed the presence of an isoelectric interval preceding the PVBs (N = 15). Pacing from the site of double potential formation accurately reproduced the surface ECG morphology (N = 15) of spontaneous PVBs. Closely-spaced epicardial mapping demonstrated delayed activation across an isoelectric interval representing “an arc of conduction block.” Rate-dependent very slow antegrade conduction through a zone of apparent conduction block (N = 8) produced decremental activation delays until the delay was sufficient to excite epicardium distal to the original “arc of conduction block,” resulting in PVB formation. Conclusion The present experiments demonstrate double potential formation and rate-dependent constant-coupled late PVB formation in infarcted dog hearts. Electrode recordings demonstrate a prolonged isoelectric period preceding PVB formation consistent with very slow conduction (<70 mm/s) across a line of apparent conduction block and may represent a new mechanism of PVB formation following myocardial infarction

Elasto-Inertial Instability in Torsional Flows of Shear-Thinning Viscoelastic Fluids

It is well known that inertia-free shearing flows of a viscoelastic fluid with curved streamlines, such as the torsional flow between a rotating cone and plate, or the flow in a Taylor-Couette geometry, can become unstable to a three-dimensional time-dependent instability at conditions exceeding a critical Weissenberg (Wi) number. However, the combined effects of fluid elasticity, shear thinning, and finite inertia (as quantified by the Reynolds number Re) on the onset of elasto-inertial instabilities are not fully understood. Using a set of cone-plate geometries, we experimentally explore the entire Wi - Re phase space for a series of rate-dependent viscoelastic fluids (quantified using a shear thinning parameter $\beta_P$). We tune $\beta_P$ by varying the polymer concentration in solutions. This progressively reduces shear-thinning but leads to finite inertial effects before the onset of elastic instability, thus naturally resulting in elasto-inertial coupling. Transient rheometric measurements and flow visualization experiments allow us to investigate the effects of flow geometry and document the combined effects of varying Wi, Re, and $\beta_P$ on the emergence of secondary motions at the onset of instability. The resulting critical state diagram quantitatively depicts the competition between the stabilizing effects of shear thinning and the destabilizing effects of inertia. We extend the curved streamline instability criterion of Pakdel and McKinley 1996 for the onset of purely elastic instability in curvilinear geometries by using scaling arguments to incorporate shear thinning and finite inertial effects. The augmented condition facilitates predictions of the onset of instability over a broader range of flow conditions, thus bridging the gap between purely elastic and elasto-inertial curved streamline instabilities

Electrophysiologic and antiarrhythmic actions of nadolol: Acute ischemia in the presence of previous myocardial infarction

The actions of the [beta]-adrenergic receptor antagonist, d,l-nadolol, were examined in anesthetized dogs subjected to circumflex coronary artery ligation in the presence of previous anterior myocardial infarction. With circumflex ligation, control dogs (N = 18) developed premature ventricular boats and ventricular tachycardia, followed by ventricular fibrillation (N = 16, 89%). Immediate arrhythmias (2 to 5 minutes) were accompanied by activation delays and continuous diastolic electrical activity in acutely ischemic epicardial tissue. Delayed arrhythmias (6 to 12 minutes) were accompanied by delayed activation and continuous diastolic electrical activity in acutely ischemic mid-myocardium. Nadolol (8 mg/kg, intravenously) (N = 10) reduced ventricular arrhythmias during both phases of arrhythmia development and increased survival (70%, p = 0.001 vs control). Nadolol failed to alter activation in acutely ischemic epicardium, but prevented beat-to-beat changes in epicardial and mid-myocardial activation. Atrial pacing of nadolol-treated animals at heart rates comparable with those of the control group reversed the beneficial effects of nadolol on the development of ventricular arrhythmias and ventricular fibrillation (70%; p = 0.07 vs nadolol; p = 0.21 vs control, respectively). The beneficial effects of nadolol could not be attributed to reduced epicardial delays, but were associated with the suppression of beat-to-beat conduction abnormalities that preceded ventricular fibrillation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27090/1/0000081.pd

Bretylium: A prototype for future development of antidysrhythmic agents

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25154/1/0000590.pd

Individual Worker level Attitudes Toward Empirically Supported Treatments

Objectives: There is a growing literature indicating that organizational and individual worker-level factors affect decisions about whether or not empirically-supported treatments (EST’s) are adopted within health care agencies. The purpose of this pilot study is to further investigate and measure worker’s attitudes within a community organization. Methods: A small organization participated in the study due to their diversity in services offered. Of the 92 workers eligible for participation in the study, 66 (72%) completed the Evidence-Based Practice Attitude Scale (EBPAS) survey. Results: Multivariate analyses revealed that female workers scored higher on both Openness and total score; workers with nursing, education or psychology majors scored lower than workers with other (excluding social work) majors on both Divergence and total score; and that older workers scored higher on Divergence. Conclusion: Although small, this study identifies individual characteristics that are most likely to fit the profile of an EST adopte

Is Openness to Using Empirically Supported Treatments Related to Organizational Culture and Climate?

An established literature indicates that organizational factors such as culture and climate can impede the implementation of empirically supported treatments (ESTs) in real world practice. What remains unclear is whether certain worker attitudes create barriers to implementing ESTs and how these attitudes might impact the working culture and climate within an organization. The overall purpose of this study is to investigate workers’ openness towards implementing a new EST and whether the workers’ openness scores relate to their workplace culture and climate scores. Participants in this study (N=1273) worked in a total of 55 different programs in a large child and family services organization. Participants completed an organizational culture and climates survey and a survey measuring their attitudes toward ESTs. Results indicate that work groups that measure themselves as being more open to using ESTs rated their organizational cultures as being significantly more proficient and significantly less resistant to change. Further, they rated their organizational climates as being significantly more functional and less stressed. Work groups with open attitudes towards using ESTs create a culture and climate that also foster using ESTs. With ESTs becoming the gold standard for professional social work practices, it is important to have accessible pathways to EST implementation

Empirically Supported Treatments Impact on Organizational Culture and Climate

Objectives: With the continued push to implement empirically supported treatments (ESTs) into community based organizations, it is important to investigate whether working condition disruptions occur during this process. While there are many studies investigating best practices and how to adopt them, the literature lacks studies investigating the working conditions in programs that currently use ESTs. Methods: This study compared the culture and climate scores of a large organization’s programs that use ESTs and those programs indicating no EST usage. Results: Of the total 55 different programs (1,273 front-line workers), 27 programs used ESTs. Results indicate that the programs offering an EST had significantly more rigid and resistant cultures, compared to those without any ESTs. In regard to climate, programs offering an EST were significantly less engaged, less functional, and more stressed. Conclusion: Outcomes indicate a significant disruption in organizational culture and climate for programs offering ESTs

Prevention of ventricular fibrillation by bretylium in a conscious canine model of sudden coronary death

In anesthetized dogs, a silver wire electrode was inserted into the lumen of the circumflex coronary artery (LCX) and myocardial infarction was produced by a temporary 90-minute occlusion of the left anterior descending coronary artery (LAD) followed by reperfusion. Four days later while in the ambulatory state, a 150 [mu]A current was applied to the intimal surface of the LCX of saline (n = 10) and bretylium (n = 10) treated animal. Intimal injury and coronary thrombosis produced ST segment changes at 138 +/- 39 minutes ([chi] +/- SEM), followed by premature ventricular beats (at 142 +/- 37 minutes), ventricular tachycardia (at 156 +/- 49 minutes), and ventricular fibrillation (at 163 +/- 51 minutes) in 9 of 10 saline-treated animals. In bretylium-treated animals, ST segment changes appeared at 128 +/- 35 minutes, with six animals surviving for 24 hours (p &lt; 0.03 vs saline). LAD infarction was present in both saline (14.1 +/- 2.3%) and bretylium (15.1 +/- 2.1% of left ventricle) treated animals with only bretylium-treated animals developing LCX infarcts (16.1 +/- 2.1%). Bretylium prevents ventricular fibrillation (VF) resulting from ischemia at a site distant to prior myocardial infarction in the conscious dog and deserves further attention as a potential antifibrillatory agent for prevention of sudden coronary death in man.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25438/1/0000888.pd

Oral and intravenous bretylium disposition

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109931/1/cptclpt1980190.pd