Studies of biotic remains of polar ice caps have been limited to morphological identification of plant pollen and spores. By using sensitive molecular techniques, we now demonstrate a much greater range of detectable organisms; from 2000- and 4000-year-old ice-core samples, we obtained and characterized 120 clones that represent at least 57 distinct taxa and reveal a diversity of fungi, plants,...

ithin the first few months of my practice, I changed the ife of a young physician referred for right ventricular (RV) utflow tract ventricular tachycardia (VT) with the diagnois of arrhythmogenic right ventricular cardiomyopathy/ ysplasia (ARVC/D). This was an uncomfortable moment, ut not one nearly as bad as “the cardiologist’s worst ightmare” (1), making the opposite mistake of missing a ife-...

The G+C nucleotide content of ribosomal RNA (rRNA) sequences is strongly correlated with the optimal growth temperature of prokaryotes. This property allows inference of the environmental temperature of the common ancestor to all life forms from knowledge of the G+C content of its rRNA sequences. A model of sequence evolution, assuming varying G+C content among lineages and unequal substitution...

A major challenge in effective active ageing support is to identify/design new organizational structures, approaches, and mechanisms so that on one hand older people do not feel excluded, and on the other hand they have the chance to make valued contributions to the communities where they live. Collaborative networks involving a variety of stakeholders, e.g. senior professionals, intermediary e...

Reaction-diffusion equations based on a polymerization model are solved to simulate the spreading of hypothetic left and right-handed life forms on the Earth’s surface. The equations exhibit front-like behavior as is familiar from the theory of the spreading of epidemics. It is shown that the relevant time scale for achieving global homochirality is not, however, the time scale of front propaga...

Introduction: Biotechnology is the means or way of manipulating life forms to provide desirable products for man’s use.1 Typically this manipulation is done through genetic engineering. Genetic Engineering is the selective, deliberate alteration of genes by man in such a way as to allow it to produce endogenous proteins with properties different from those of the normal, or to produce entirely ...

Life emerged on Earth in an anaerobic environment, bathed in noxious gases. Among these gases, the role of hydrogen sulfide is significant since this gas, was required as a building block of life, contributed to abiogenic generation of organic compounds that gave rise to life and drove adaptations of life throughout its entire evolutionary path. During evolution, hydrogen sulfide contributed to...

Artificial Life as a field of research attempts to synthesize life in silico by using computers to create virtual life. By definition life and artificial life should display the following characteristics: self-organization, metabolization, self-reproduction, and adaptive evolution. Until now, most Artificial Life inspired artworks have created artificial characters or creatures that display som...

Acytota is a kingdom of life covering satellites, plasmids, transposable elements, viroids and viruses, all outside the conventional tree of life but satisfying most life definitions. This review focuses on some aspects of Acytota, their "genomes" and life styles, the dominance of transposable elements and their evolutionary influence on other life forms in order to vindicate the Acytota as a l...

abiotic factors, as topographic and physicochemical properties of soil, are the most important effective factor on vegetation in rangeland ecosystems which have the most important performances to forming and succession of plant vegetation. ecologic management of rangelands can be desired by better understanding of these effective factors. then, rangeland of javaherdeh (ramsar) in the northern a...