A dynamical system is called positive if any solution of the system starting from nonnegative states maintains nonnegative states forever. In many applications where variables represent nonnegative quantities we often encounter positive dynamical systems as mathematical models see 1, 2 , and many researches for positive systems have been done actively; for recent developments see, for example, ...

This paper compares and contrasts financial strength ratings assigned by Value Line, Standard and Poor's, and Moody's. All of these rating agencies use modified ratings. When modifiers are considered, these agencies agree between 85 97 percent of the time. A model using stock market information as well as liquidity, leverage, activity and profitability ratios is presented. Cronbach's alpha, a m...

This study aimed to determine whether cough at night keeps children awake, to describe the relationship between children's cough and sleep and to report parents' perceptions of their children's cough and sleep. Thirty-nine children with reported persistent cough at night (>3 weeks) were recruited and studied for 6 nights by video-recording. Coughs were counted and sleep state was coded for awak...

We review the intimate connection between (super-)gravity close to a spacelike singularity (the "BKL-limit") and the theory of Lorentzian Kac-Moody algebras. We show that in this limit the gravitational theory can be reformulated in terms of billiard motion in a region of hyperbolic space, revealing that the dynamics is completely determined by a (possibly infinite) sequence of reflections, whi...

The more important criteria for identification of the S form of H. pertussis and for its differentiation from R variants are presented in summary fashion in Table IV. The differences as indicated in detail in the foregoing sections and as shown briefly in this tabulation are so clear-cut that they call for little, if any, further comment. Of all the differential characteristics, the morphologic...

Failure to access healthcare is an important contributor to child mortality in many developing countries. In a national household survey in Malawi, we explored demographic and socioeconomic barriers to healthcare for childhood illnesses and assessed the direct and indirect costs of seeking care. Using a cluster-sample design, we selected 2,697 households and interviewed 1,669 caretakers. The ma...