Despite extensive growth in recent years, the field of "quality-of-life" appraisal still evokes debate about basic perception of the concept and is accompanied by a plethora of indexes for measurement. One prime reason for the problems is that the measurements have been transferred from two separate sources - medical health status indexes and social-science population indexes - neither of which...

During the first half of the twentieth century, many scientists considered viruses the smallest living entities and primitive life forms somehow placed between the inert world and highly evolved cells. The development of molecular biology in the second half of the century showed that viruses are strict molecular parasites of cells, putting an end to previous virocentric debates that gave viruse...

OBJECTIVES This report presents complete period life tables by Hispanic origin, race for the non-Hispanic white and non-Hispanic black populations, and sex for the United States based on age-specific death rates in 2006. METHODS The methods used to estimate the probability of death for ages 0-80 for the Hispanic population and 0-65 for the non-Hispanic white and non-Hispanic black populations...

Almost all modern proteins possess well-defined, relatively rigid scaffolds that provide structural preorganization for desired functions. Such scaffolds require the sufficient length of a polypeptide chain and extensive evolutionary optimization. How ancestral proteins attained functionality, even though they were most likely markedly smaller than their contemporary descendants, remains a majo...

A number of small RNA sequences, located in different non-coding sequences and highly preserved across the tree of life, have been suggested to be molecular fossils, of ancient (and possibly primordial) origin. On the other hand, recent years have revealed the existence of ubiquitous roles for small RNA sequences in modern organisms, in functions ranging from cell regulation to antiviral activi...

The concept of an (M,R) system with organizational invariance allows one to understand how a system may be able to maintain itself indefinitely if it is coupled to an external source of energy and materials. However, although this constitutes an important step towards understanding the difference between a living and a non-living system, it is not clear that an (M,R) system with organizational ...

We revisit the case for the hyperthermophilic scenario for the origin of life and the last common ancestor. Evidence includes studies of phylogenetic trees, rRNA, G and C content, hyperthermophilic proteins, correlations between maximal temperature tolerances and genetic distances, saline stabilization of DNA/RNA, and the inferred climatic temperatures of the early Earth. Although some doubts r...