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PubMed2005

Redefining science.

Explore the source record for details and available documents.

Biological Evolution↗
PubMed1968

Biologic effects of supernovae.

Estimates of the probability that nearby explosions of supernovae have occurred during the earth's history and the biologic effects of the radiation therefrom are presented. They suggest that cosmic radiation from supernovae could have caused the extinction of many exposed animals without the simultaneous extinction of plant life. This suggests that supernovae should be considered as one possible mechanism by which fauna become extinct.

Animal Population Groups↗
PubMed1968

Life's irreducible structure. Live mechanisms and information in DNA are boundary conditions with a sequence of boundaries above them.

Mechanisms, whether man-made or morphological, are boundary conditions harnessing the laws of inanimate nature, being themselves irreducible to those laws. The pattern of organic bases in DNA which functions as a genetic code is a boundary condition irreducible to physics and chemistry. Further controlling principles of life may be represented as a hierarchy of boundary conditions extending, in the case of man, to consciousness and responsibility.

Biological Evolution↗
PubMed1974

Brave new world?

Recent developments in biology and medicine are raising new problems in the prevention and treatment of birth defects, and in research on these diseases. The problems include immediate issues such as genetic counseling, abortion for birth defects, the withholding of complex treatments from individuals in some situations, screening for genetic and other diseases, artificial insemination, and fertilization in vitro. Other problems, such as the dysgenic effects of modern medicine and the possibilities of cloning and gene therapy, are more remote. Each of these issues should be considered on its own merits and by its immediate and remote consequences rather than by a priori absolute criteria. Ways must be found to deal with these issues in a manner acceptable to most human beings. Open discussions and freedom from coercion are the best guarantees for ultimate success. The ethical human brain is the highest accomplishment of biologic evolution. By harmonizing our scientific, cultural, and ethical capabilities, the potentially achievable results can place us at the threshold of a new era of better health and less human suffering.

Abortion, Legal↗
PubMed1990

Protein sorting to mitochondria: evolutionary conservations of folding and assembly.

According to the endosymbiont hypothesis, mitochondria have lost the autonomy of their prokaryotic ancestors. They have to import most of their proteins from the cytosol because the mitochondrial genome codes for only a small percentage of the polypeptides that reside in the organelle. Recent findings show that the sorting of proteins into the mitochondrial subcompartments and their folding and assembly follow principles already developed in prokaryotes. The components involved may have structural and functional equivalents in bacteria.

Amino Acid Sequence↗
PubMed1989

Contributions of bird studies to biology.

Birds are widely distributed, highly diversified, and exhibit behavior and social organizations equal in complexity to mammals, yet they are generally more conspicuous and approachable in natural environments. These attributes make birds excellent subjects in many areas of biological research. The topics in which studies on birds have figured prominently include the mechanisms of species formation, the regulation of the distribution and abundance of animals, the effects of the environment on behavior and physiology, the biological and evolutionary significance of variations in social organizations, the encoding of information in animal communication, the sensory basis for migration and navigation, the effects of hormones on nerve cells and behavior, the ontogeny of brain and behavior, and the structure and function of the vertebrate brain. The outstanding record of avian research suggests that birds will continue to provide important models for developing and testing new ideas in various fields of biology.

Adaptation, Physiological↗
PubMed1996

The Edge of Time: Dating Young Volcanic Ash Layers with the 40Ar-39Ar Laser Probe

Argon-40-argon-39 single-crystal dating of young (5000 to 30,000 years ago) volcanic ash layers erupted from the Mono Craters, California, shows that the method can yield meaningful ages in Holocene tephra. Because of ubiquitous xenocrystic contamination, the data do not form isochrons but plot in wedge-shaped regions on an argon isotopic diagram. The upper boundary of the region is an isochron matching the 14C-derived age of the eruption. Such contamination-related patterns may be common in dating young materials by the single-crystal method. Argon dating by this method can help refine the time scale of physical and biological evolution over the past 100,000 years.

Journal Article↗