Yonkers, City of and International Brotherhood of Teamsters

In the Matter of the Impasse between City of Yonkers and International Brotherhood of Teamsters. Case No. M2008-065. I. Leonard Seiler, Fact Finder. Issued in Hackensack, New Jersey

The modeling and simulation of feedback control systems

A brief description of the principles of mathematical models and their development is given. It should serve as an introduction to those unfamiliar with the topic

The behavior of renal-regulating hormones during hypogravic stress

The regulation of fluid and electrolyte behavior during space flight is believed to be under control, in large part, of a group of hormones which have their major effects on renal excretion. The hormones studied include renin-angitensin, aldosterone, and antidiuretic hormone (ADH). The regulatory systems of these renal-regulating hormones as they act individually and in concert with each other are analyzed. The analysis is based on simulations of the mathematical model of Guyton. A generalized theory is described which accounts for both short-term and long-term behavior of this set of hormones

Intangible assets and national income accounting

In this paper I focus on three related and difficult areas of the measurement of national income. I argue that the economic theory underlying measurement of these items is currently controversial and incomplete.National income

Validation of a model for investigating red cell mass changes during weightlessness

The model, both the conceptual model and simulation model, provided a convenient framework on which to demonstrate the commonality between such diverse stresses as descent from altitude, red cell infusions, bed rest, and weightlessness. The results suggest that all of these stresses induce an increased blood hematocrit leading to tissue hyperoxia and eventual inhibition of the erythyocyte producing circuit until the hyperoxic condition is relieved. The erythropoietic system was acting, in these situations, as if it were an hematocrit sensor and regulator. In these terms the decreases in red cell mass during Skylab may be explained in terms of normal feedback regulation of the erythropoietic system in the face of sustained decreases in plasma colume

Economics and the new economy: the invisible hand meets creative destruction

In the 18th century, Adam Smith offered his theory of the invisible hand and the view that perfect competition is the main spur to economic efficiency. The theory of the invisible hand, as it has evolved in modern economic thought, treats creative activity as being outside the scope of economic theory. In the 20th century, Joseph Schumpeter offered an alternative perspective: creativity is an economic activity. He argued that a capitalist market system rewards change by allowing those who create new products and processes to capture some of the benefits of their creations in the form of short-term monopoly profits, a situation that promotes what Schumpeter called "creative destruction." What should the fundamental paradigm of economics be: creative destruction or the invisible hand? In this article, Leonard Nakamura offers some possible answers to this question.[Adobe Acrobat (.pdf)Economic development ; Productivity ; Wages

Description, validation, and modification of the Guyton model for space-flight applications. Part A. Guyton model of circulatory, fluid and electrolyte control. Part B. Modification of the Guyton model for circulatory, fluid and electrolyte control

The mathematical model that has been a cornerstone for the systems analysis of space-flight physiological studies is the Guyton model describing circulatory, fluid and electrolyte regulation. The model and the modifications that are made to permit simulation and analysis of the stress of weightlessness are described

User's instructions for the 41-node thermoregulatory model (steady state version)

A user's guide for the steady-state thermoregulatory model is presented. The model was modified to provide conversational interaction on a remote terminal, greater flexibility for parameter estimation, increased efficiency of convergence, greater choice of output variable and more realistic equations for respiratory and skin diffusion water losses

An Integrated Analysis of the Physiological Effects of Space Flight: Executive Summary

A large array of models were applied in a unified manner to solve problems in space flight physiology. Mathematical simulation was used as an alternative way of looking at physiological systems and maximizing the yield from previous space flight experiments. A medical data analysis system was created which consist of an automated data base, a computerized biostatistical and data analysis system, and a set of simulation models of physiological systems. Five basic models were employed: (1) a pulsatile cardiovascular model; (2) a respiratory model; (3) a thermoregulatory model; (4) a circulatory, fluid, and electrolyte balance model; and (5) an erythropoiesis regulatory model. Algorithms were provided to perform routine statistical tests, multivariate analysis, nonlinear regression analysis, and autocorrelation analysis. Special purpose programs were prepared for rank correlation, factor analysis, and the integration of the metabolic balance data

Skylab water balance error analysis

Estimates of the precision of the net water balance were obtained for the entire Skylab preflight and inflight phases as well as for the first two weeks of flight. Quantitative estimates of both total sampling errors and instrumentation errors were obtained. It was shown that measurement error is minimal in comparison to biological variability and little can be gained from improvement in analytical accuracy. In addition, a propagation of error analysis demonstrated that total water balance error could be accounted for almost entirely by the errors associated with body mass changes. Errors due to interaction between terms in the water balance equation (covariances) represented less than 10% of the total error. Overall, the analysis provides evidence that daily measurements of body water changes obtained from the indirect balance technique are reasonable, precise, and relaible. The method is not biased toward net retention or loss