Soil biofilters and related systems based onthe use of natural filter beds have been usedfor several years for solving specific airpollution problems. Over the past decade,significant improvements have been brought tothese original bioprocesses, among which thedevelopment and use of new inert packingmaterials. The present paper overviews the mostcommon inert packings used in biofiltration ofwas...

This paper presents an algorithm for computing algebraically relative resolvents which enhances an existing algorithm by avoiding the accumulation of superfluous powers in the intermediate computations. The superfluous power generated at each step is predetermined over a certain quotient ring. As a byproduct, an efficient algorithm for extracting an n-th root of a univariate polynomial is obtai...

The Penna model is a model of evolutionary ageing through mutation accumulation where traditionally time and the age of an organism are treated as discrete variables and an organism's genome is represented by a binary bit string. We reformulate the asexual Penna model and show that a universal scale invariance emerges as we increase the number of discrete genome bits to the limit of a continuum...

In this paper, we present an overlapping generations model where individuals accumulate human capital through formal schooling. We model the role of the public sector in schooling as one of collecting taxes from households and providing inputs to the learning technology. Public expenditures on schools are determined endogenously. Under plausible restrictions, our model's predictions qualitative...

The mutation accumulation hypothesis predicts that sex functions to reduce the population mutational load, while the Red Queen hypothesis holds that sex is adaptive as a defense against coevolving pathogens. We used computer simulations to examine the combined and separate effects of selection against deleterious mutations and host-parasite coevolution on the spread of a clone into an outcrossi...

Kant’s work contains numerous inspiring ideas regarding knowledge, morality, and beauty, and I will attempt to present some of them in this short essay. Following are very brief summaries of the main lessons that I suggest to take home. Knowledge is a synthesis of concepts and sensory data; it is never obtained by sheer accumulation of data (or facts); it is obtained by the organization of mean...

In [6], Yoshikazu Yasui formulates some results on relative countable paracompactness and poses some questions. Like it is the case with many other topological properties [1], countable paracompactness has several possible relativizations. Thus a subspace Y ⊂ X is called countably 1-paracompact in X provided for every countable open cover U of X there is an open cover V of X which refines U and...

The experience of experts relies on the process of decision-making jointly with the progressive elaboration of a context-specific model. However, context modeling generally stays implicit because only the result of the decisionmaking process matters. Modeling context within a decision-making process supposes a uniform representation of knowledge, reasoning and contexts. In the Contextual-Graphs...

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Concern has been voiced about the survival of endangered species, and even the long-term prospects for humans, in the face of accumulating deleterious mutations. Two experiments have investigated the mutation accumulation process in laboratory Drosophila populations, with apparently conflicting results.