6,148 research outputs found
Quality assurance program guidelines for application to and use by manufacturers of rail/guideway vehicles, buses, automatic train control systems, and their major subsystems
Guidelines are presented for a quality assurance system to be implemented by the manufacturer in support of designing, developing, fabricating, assembling, inspecting, testing, handling, and delivery of equipment being procured for use in public urban mass transit systems. The guidelines apply to this equipment when being procured for: (1) use in revenue service; (2) demonstration of systems that will be revenue producing or used by the public; (3) use as a prototype for follow-on operational/revenue producing equipment procurements; and (4) qualification tests
Human monstrosities: their origin and treatment
1. Human monstrosities are of great interest to the
physician, surgeon, and obstretician.
|| 2. Until the 19th century, malformations were attributed to the influences of wrathful gods, devils,
witches, sex perversions, the moon, eclipses,
comets, and "maternal impressions".
|| 3. Scientific teratology only commenced in the
17th century.
|| 4. Connections between animals of different species
have been proved conclusively to be sterile.
|| 5. Germinal life of embryo lasts about one week.
|| 6. Embryonic life lasts about five weeks.
|| 7. Foetal life lasts for the remainder of the
ante-natal period.
|| 8. Normal development is a form of twinning -
"symmetrical division".
|| 9. Uniovular twins originate from one ovum, and is
not a normal physiological process.
|| 10. Double monsters also originate from one ovum,
and are due to partial fission of embryonic axis.
|| 11. Binovular twinning is not true twinning.
|| 12. The armadillo has supplied valuable data regarding
early mammalian development.
|| 13. The corpus luteum is a guide as to the number
of ova involved in a pregnancy.
|| 14. There is a period of quiescence of about three
weeks in early development of the armadillo.
This may explain its polyembryony, and may
also explain uniovular twinning in man.
|| 15. Twinning is due to a period of quiescence as
a result of an upset in the growth regulating
mechanism of the ovum.
|| 16. In epignathus we have complete fission with
partial inclusion
|| 17. In foetus in foetu we have complete fission
with total inclusion.
|| 18. Malformations can be produced experimentally
in some animals by:
(1) violent agitation,
(2) variations in physiochemical conditions,
(3) variations in temperature, and
(4) disturbance of normal respiratory interchange.
|| 19. The principal causes of human malformations are:
(1 )amniotic bands or adhesions,
(2) faulty implantation of ovum due to endometritis,
(3) developmental arrest at critical stases
of gastrulation, and
(4) heredity.
|| 20. There is a growth regulating mechanism in the ovum.
|| 21. This mechanism is controlled by two ovular secretions:
"inhibitin" which inhibits growth, and
"stimulin" which stimulates growth.
|| 22. Normal tissues contain a similar mechanism with
similar secretions.
|| 23. In ante-natal life, inco-ordination between
these two factors leads to mal- developments
and. monsters,
|| 24. In post -natal life such into -ordination results
in simple or malignant growths.
|| 25. "Inhibitin" may prove a powerful "de- cancerising" agent
|| 26. "Stimulin" may prove equally useful in most
clinical conditions of a non -malignant nature
requiring the speeding-up of tissue repair.
|| 27. Surgery has a distinct field of usefulness in
certain cases of double monsters namely,
omphalopagus parasiticus, xiphopagus, thoracopagus
and craniopagus.
|| 28. Heredity is a potent factor in physical and mental
peculiarities in the offspring.
|| 29. There is a constant tendency towards recovery
and return to a healthy stock.
|| 30. Eugenics is " the study of the agencies under social control that may improve or impair the racial qualities of future generations, either physically or mentally".
|| 31. Mendel's laws of heredity have been found also applicable in man as regards mental and physical characters.
|| 32. Several methods for checking the supply of human defectives have been proposed e.g. segregation, sterilisation, restrictive marriage, laws, etc.
|| 33. Eugenics is one of the world's most pressing problems
A Theory of Impact Bonds as an Alternative to Pigouvian Tax and Public Provision: Application for Climate Change
Instead of addressing externalities with taxes or subsidies, this paper proposes a process in which the government estimates the overall cost of an externality and then offers a lesser amount to the private enterprise that resolves the externality. This paper offers a theoretical framework for resolving externalities, applies this as a theory of social impact bonds, and uses private industry solutions to climate change as an example of how this process would work. Government could therefore identify the social price of public problems, offer a lesser amount to fix them, and then allow investors to organize markets around potential solution
A Painting in Progress
A series of original sketches accompanied by comments from the artist. Page 43
Nuclear segregation and the delayed appearance of induced mutants in Escherichia coli
The existence of a cytologically demonstrable nucleus in the bacterial cell is no longer seriously in question. There is, however, no direct evidence that the Feulgen-positive staining bodies generally considered to represent the nuclear or chromosomic elements of the bacterium are actually carriers of genetic material. The chromosome theory of heredity has yet to be established for bacteria.
Current acceptance of the bacterial nucleus as a cytological entity stems largely from the work of investigators who demonstrated bodies having typically nuclear reactions to stains and enzymes (Stille, 1937; Piekarski, 1940; Robinow, 1945; Tulasne and Vendrely, 1947, among others). Although there is no general agreement among bacterial cytologists as to the finer organization and structure of the nuclear body, and as to its pattern of division (see Delaporte, 1950; Bisset, 1950; Knaysi, 1951), the observation that serves as the starting point of this investigation is, I believe, sufficiently conservative to find general acceptance: namely, that the number of visibly distinct nuclear bodies (or chromosomes, or nuclear elements) is larger in logarithmically dividing cells of Escherichia coli than in resting cells
Witkin III
I am fortunate to have as my respondents two scholars who have made, and continue
to make, important contributions to what Professor Alexander terms the “strong
program” for a sociology of the aesthetic. They have responded in very different
ways. Professor Atkinson has used the occasion to present a personal commentary
on the sociological neglect of the aesthetic dimension and has explored the
implications of recent thinking and ethnographic research that responds to that
neglect by bearing upon issues that are linked to those I raise. Because Professor
Atkinson’s paper does not directly address the arguments in my paper, I have been
invited by the editors to reply specifically to the critical comments made by Professor
Alexander in his response to my work. The space allocated to me for my reply will
only permit me to focus on his central argument to the exclusion of other points he
make
Effect of nucleic acid on phenomic lag in Escherichia coli
When a series of 50 tubes of broth containing 0.5% sodium ribonucleate (Schwartz) is inoculated with strain B/r of Escherichia coli, the cultures obtained after 48 hours of incubation contain, on the average, a significantly higher number of mutants resistant to bacteriophage T 1 than a similar series of cultures grown without nucleate
Effects of temperature on spontaneous and induce mutations in Escherichia coli
The frequency of spontaneous mutations in Drosophila has been shown to increase, in general, with increasing temperature, and the temperature coefficients reported range from about 2 to 5(1). These findings played an important part in the early definition of mutation as a definite molecular rearrangement(2). Very little is known of the response to post-treatment temperature of mutations induced by radiation or chemicals. Two kinds of effects could be investigated in this connection: the effect of temperature on the frequency of induced mutations, and the effect of temperature on the pattern of delayed appearance of induced mutations. In the latter category, Auerbach(3) has described an increase in the frequency of mustard-induced mosaics at low temperatures, which she ascribes to the stabilization by cold of metastable genic configurations induced by the mutagen, leading to extended delay in the shift to the stable mutant condition. Similar effects of temperature on the delayed action of mutagens in Neurospora and Aspergillis found in unpublished experiments by the authors are mentioned by McElroy and Swanson(4) in support of the concept of mutation via metastable intermediates. The hereditary change from sensitivity to resistance to bacteriophage in Escherichia coli can be followed with a degree of quantitative precision and technical ease that makes it a promising material for an investigation of temperature effects on spontaneous and induced mutation. This report is a preliminary account of such a study
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