Evolutionary algorithms (EAs), such as the differential evolution (DE) algorithm, suffer from high computational time due to large population size and nature of evaluation, to mention two major reasons. The micro-EAs employ a very small population size, which can converge to a reasonable solution quicker; while they are vulnerable to premature convergence as well as high risk of stagnation. One...

A hydrodynamic model involving cooling gas in the stagnation region of a collimated outflow is proposed for the formation of the giant parsec-scale bipolar envelope that surrounds the planetary nebula KjPn 8. Analytical calculations and numerical simulations are presented to evaluate the model. The envelope is considered to consist mainly of environmental gas swept-up by shocks driven by an epi...

We examine global economic dynamics under learning in a New Keynesian model in which the interest-rate rule is subject to the zero lower bound. Under normal monetary and fiscal policy, the intended steady state is locally but not globally stable. Large pessimistic shocks to expectations can lead to deflationary spirals with falling prices and falling output. To avoid this outcome we recommend a...

This paper discusses the impact of externalities on economic growth and the long term distribution of economic activities in a system of two regions. We use a standard neoclassical growth model of the Solow-type and augment it with a random process of innovation allocation. The long term behavior of this model is analyzed. As it turns out the dynamic behavior of our model differs fundamentally ...

Background. Traditional Chinese medicine (TCM) has long been used to treat chronic atrophic gastritis (CAG). The aim of the present study was to evaluate the TCM syndrome characteristics of CAG and its core pathogenesis so as to promote optimization of treatment strategies. Methods. This study was based on a participant survey conducted in 4 hospitals in China. Patients diagnosed with CAG were ...

While “avoiding stagnation” has been the mantra of building water experts, support for how this terminology is used not overly convincing. Carefully nuanced COVID stagnation studies can improve quality research and communication strategies.