Recent developments in genetic data analysis: what can they tell us about human demographic history? (25/38)

Over the last decade, a number of new methods of population genetic analysis based on likelihood have been introduced. This review describes and explains the general statistical techniques that have recently been used, and discusses the underlying population genetic models. Experimental papers that use these methods to infer human demographic and phylogeographic history are reviewed. It appears that the use of likelihood has hitherto had little impact in the field of human population genetics, which is still primarily driven by more traditional approaches. However, with the current uncertainty about the effects of natural selection, population structure and ascertainment of single-nucleotide polymorphism markers, it is suggested that likelihood-based methods may have a greater impact in the future.  (+info)

Concurrent phenomena of science and history in the 17th century and their essential interdependence. (26/38)

The explanation for the explosion of science in the 17th century lies in history and medical historiography. Without this approach, it becomes fantasy, accidents, or success stories. Sigerist grasped the essential interdependence of science and history, and had no need for devised reasons or speculation. He realized that once the dark night of the Middle Ages was over, the sciences arose with undreamt of force and accelerated development. The advances in astronomy, mathematics, mechanics, and experimental science benefitted a society developing in seafaring, manufacture, and trade in the 17th century. Sigerist's views make the scientific explosion understandable in human and social terms. He did not overlook the capabilities of some extraordinary individuals, such as Paracelsus (1493-1541), to shape the course of medicine, nor the importance of the mechanistic philosophy in the 17th century. Man makes history and science; hence, we find concurrent phenomena of history and science essentially interdependent. The spirit of experimental science of 17th century England was inspired by the new needs of commercial enterprise for more means of transportation and communication. Likewise, the interest in the mechanics of the pump for waterworks and for the drainage of swamps led Harvey to think of the heart as a pump, and to explain the circulation of the blood in terms of its functioning.  (+info)

Conceptualizing the world: lessons from history. (27/38)

Throughout history, philosophers, scientists, and other scholars have named and organized the salient elements of the world. These efforts have led to conceptualizations that differ widely in both content and form. This paper argues that all conceptualizations are biased, both because they depend on the purposes for which they have been created, and because they are closely tied to the world view of their designers. This bias needs to be recognized, and its consequences need to be addressed if the conceptualizations are to be used for purposes other than those for which they were designed. The paper begins with a brief overview of the disciplines that have been concerned with conceptualizing particular domains. This is followed by a non-exhaustive, illustrative, historical perspective, and the paper concludes with the interesting case study of biological taxonomy.  (+info)

Sex determination in mythology and history. (28/38)

The history of ideas on how the sexes became divided spans at least three thousand years. The biblical account of the origin of Eve, and the opinions of the philosophers of classical Greece, have unexpected bearings on present-day ideas. The scientific study of sex determination can be said to have begun in the 17th century with the discovery of spermatozoa, but the origin and function of the "spermatic animalcules" eluded investigators until 1841. The mammalian egg was discovered in 1827, and in the last quarter of the century fertilization was observed. The view current at that time, that sex determination was under environmental control, gave way to the idea of chromosomal determination in the first quarter of the 20th century. The study of human and other mammalian chromosomes during the third quarter of the century, and the discovery of sex-chromosome abnormalities, emphasized the importance of the Y chromosome for male sex determination. The last quarter of the century witnessed a hunt for the "testis-determining" gene, thought to be responsible for the differentiation of Sertoli cells, and culminating in the isolation of SRY (Sry in the mouse). However, an increasing number of additional genes and growth factors were found to be required for the establishment of male sex. During the same period evidence emerged that male development was accompanied by enhanced growth, both of gonads and whole embryos. An unexpected finding was the demonstration of temperature-dependent sex determination in reptiles. With the advent of the 21st century, it was shown that Sry induces cell proliferation in fetal mouse gonads, and it has been suggested that male sex differentiation in mammals requires a higher metabolic rate. These insights could lead to a better understanding and improved treatment of abnormalities of sexual development.  (+info)

Histamine H2 receptor trafficking: role of arrestin, dynamin, and clathrin in histamine H2 receptor internalization. (29/38)

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Botulinum neurotoxin vaccines: Past history and recent developments. (30/38)

Botulinum toxin may cause a neuroparalytic illness that may result in respiratory failure and require prolonged mechanical ventilation. As medical resources needed for supportive care of botulism in a bioterrorist event may quickly overwhelm the local healthcare systems, biodefense research efforts have been directed towards the development of a vaccine to prevent botulism. While human botulism has been caused only by toxin serotypes A, B, and E (rarely serotype F), all seven known immunologically distinct toxin serotypes (A - G) may potentially cause intoxication in humans from a bioterrorist event. A pentavalent (ABCDE) botulinum toxoid (PBT) has been administered as an investigation new drug (IND) to at-risk individuals for nearly 50 years. Due to declining immunogenicity of the PBT, research efforts have been directed at development of both improved (less local reactogenicity) botulinum toxoids and recombinant vaccines as potential vaccine candidates to replace the PBT.  (+info)

Formulating a historical and demographic model of recent human evolution based on resequencing data from noncoding regions. (31/38)

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The peopling of Europe from the mitochondrial haplogroup U5 perspective. (32/38)

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