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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Genetics and Cytotaxonomy in Birdsfoot Trefoil (Lotus corniculatus L.)

Bubar, John Stephen. January 1957 (has links)
Birdsfoot trefoil (Lotus corniculatus L.) is one of our leguminous forage crops. It has gained some importance in North America since 1934, when Professor Johnstone-Wallace of Cornell University found a type adapted to New York State. It appears to be especially suited to long term pasture seedings and to have a very definite place in modern grassland farming and soil conservation practices. [...]
2

Sex Ratio of the Offspring of X-Irradiated or Nitrogen Mustard Treated Male Mice.

Trasler, Daphne G. January 1954 (has links)
The present investigation was undertaken to study the etfect X-irradiation on the sex ratio of the offspring to irradiated male mice. It also appeared worthwhile to find out whether nitrogen mustard would exert etfects similar to those suspected of X-rays on sex ratio (Kalmus et al, 1952), since many of the effects nitrogen mustard exerts on the living organism are strikingly similar to the effects of radiations(Boyland, 1952; Bastrup-Madsen, 1951).
3

Genetic and Other Factors Influencing the Pathogenesis of Cleft Palate in Mice.

Trasler, Daphne G. January 1958 (has links)
The rapidly growing field of teratology has recorded an amazing variety of developmental aberrations, either "spontaneous", or with some more or less clear-cut genetic or environmental cause. This preliminary descriptive stage is certainly necessary as a guide to the further, more detailed, study of the pathogenesis of individual abnormalities. However no matter how many more abnormalities are added to the list this method will add very little to knowledge of the basic causes of developmental defects. [...]
4

Genetic analysis of UV-induced mutations and segregation in diploid aspergillus nidulans.

Chen, Andrew. T-L. January 1963 (has links)
That treatment with ionizing radiation will produce chromosomal rearrangements has been recognized ever since the classical study in Drosophila by Muller and Altenberg (1928). Studies in which treatments with ultraviolet irradiation and X-ray irradiation have been compared for the production of translocations have shown that ultraviolet irradiation produces fewer translocations than x-ray irradiation (Stadler and Sprague 1937; Stadler 1941; Emmerling 1955). In the micro-organism Aspergillus nidulans, a high frequency of chromosomal rearrangements (translocations) was round to be induced by gamma-irradiation (Tector 1961).
5

A chromatographic approach to the biosystematics of Lotus (Leguminosae).

Harney, Patricia. M. January 1963 (has links)
The study of the biochemical diversity or organisms as an aid to their taxonomic and phylogenetic classification is a comparatively recent innovation in biology. Since there are many natural chemical constituents present in plants which may be used in systematic studies many techniques for their analysis have been devised. The advent of paper chromatography in 1944, followed by the development of such techniques as electrophoresis, thin layer chromatography and gas chromatography, which enables the separation of a wide range of compounds in a relatively short time, has removed the difficulty of isolating many biochemical compounds which had been the main drawback to this type of study in the past.
6

A model of natural selection based on a mathematical theory of guessing.

Warburton, Frederick. E. January 1963 (has links)
The purpose of this thesis is to introduce a new mathematical approach to the study of evolution by natural selection. Practically all of contemporary mathematical evolution theory is encompassed by the field of population genetics, which takes the empirical facts of Mendelian genetics as given and infers their evolutionary consequences. The writer has approached the subject from the opposite direction. This thesis takes the occurrence of evolution by natural selection as a given fact, and emphasizes that mere chance could not have produced the highly adapted organisms we see around us within the limitations of time and space to which natural selection has been restricted. It then attempts to infer the properties of a genetic system, and other conditions, which are necessary and sufficient to allow natural selection to have yielded products so different from those which would have been yielded by chance alone.
7

Chromosomal aberrations in familial multiple malformations in man.

Dallaire, Louis. M. January 1964 (has links)
Note: Missing Page 135. / One of the main unsolved problems of medicine today is the fact that the frequency of human congenital malformations has shown no reduction in spite of the recent spectacular advances in understanding and treatment of human disease. The twentieth century has seen the successful application of the Mendelian laws to problems of disease transmission in man, leading to the brilliant elucidation of gene action in biochemical terms exemplified by the inborn errors of metabolism (Garrod, 1923) and the abnormal hemoglobins (Ruchnagel and Neel, 1962) and the development of refined methods to study the morphology of human chromosomes, leading to the identification, within the last few years, of a new group of human diseases, the chromosomal aberrations.
8

The genetics basis of spontaneous cleft lip in the inbred a/jax mouse strain.

Davidson, Jefferson. G. January 1964 (has links)
Although genetic studies are devoted, for the most part, to characters showing clear cut segregation, a great many genetically determined defects show familial patterns which cannot be explained by a difference at a single genetic locus or even a very few loci. These defects are often biologically important and, in spite of the difficulties involved in their analysis, deserve more intensive study. The studies which have been done, such as those of Wright (1934a, 1934b), Reed (1936), Gruneberg (1952), Lerner (1954), and Landauer (1957), attempt to explain the apparently non-Mendelian behaviour of the trait in question by invoking either reduced penetrance or multigenic inheritance, or both.
9

Strain differences in the teratogenic effects of 6-aminonicotinamide in mice.

Goldstein, Marc. B. January 1964 (has links)
Although the fact that man might produce malformed offspring in animals by altering the maternal environment was stated in the Bible (Genesis 30), when Jacob caused Laban’s sheep and goats to have striped and speckled young by holding striped rods in front of the females at the moment of conception, experimental teratology is a relatively new field. Hale, the first scientific mammalian experimental teratologist, produced a litter of 11 eyeless pigs by feeding the mother a vitamin A deficient diet (1933). At the present time most teratologist, have progressed from merely producing malformations and enumerating them, to making use of the malformations for the study of their pathogenesis and the role played by the genetic background of the mother and embryo in the production of the malformation in question.
10

The genetics of ragweed hay fever.

Kallio, Eleanor. I. January 1964 (has links)
Ragweed hay fever makes thousands of people miserable every year. These people have an allergy to ragweed pollen. The characteristic symptoms include rhinitis, sneezing, nasal blockage and itching of the nose, eyes and throat. These symptoms appear in sensitive people soon after ragweed pollen is introduced into the environment. They occur every year from about the middle of August until the first frost, during the time that the wind-pollinated plant is dispersing its heavy load of pollen. The plants causing most trouble are the short ragweed, Ambrosia artemisiifolia L. var. elatior (L.) Descourtils, giant ragweed, Ambrosia trifida L., and western ragweed, Ambrosia psilostachya DC. var. coronopifolia (T. & T.) Farw. (Bassett and Frankton, 1961).

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