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Some Effects of Solid Rocket Motor Fuel Exhausts on Avian EmbryosDeGuehery, Lindsey Elliott 01 January 1976 (has links) (PDF)
Fertile White Leghorn (Gallus gallus) and Bobwhite Quail (Colinus virginianus) were subjected to 15 min exposures produced by burning solid rocket motor (SRM) fuel. Comparative mortality data were collected. Chicken eggs were further used to study the effects of exposure on water relations and blood gas parameters. Chicken embryos exposed once on day 19 or incubation demonstrated and LD50 of 204 ppm; the LD50 for quail embryos was 175 ppm. When mortality was regressed on the final exposure concentration, chicken and quail embryos exposed on days 12 and 19 showed LD50's of 127 and 86 ppm respectively, and embryos exposed on days 4, 12, and 19 had LD50's of 75 and 56 ppm. Quail embryos appeared to be more sensitive to SRM exhausts than chicken embryos, probably owing to the larger surface area to volume ration of the egg. Embryos exposed to a small daily concentration had an MLC of 117 ppm and an LD50 of approximately 200 ppm for cumulative exposure concentrations. This suggested that individual exposures were additive in effect. Eggs exposed at temperatures less than 37.5 C showed reduced lethality, while exposures at greater temperatures increased lethality. The rate of water loss from chicken eggs measured over an eight hour period increased 5 times because of a 15 min exposure. Since the increased rate of dehydration occurred during the exposure, the hydroscopic effects of exposure were extreme. When eggs lose the 18% of the initial weight normally lost from evaporation during incubation due to exposure, no more water loss was seen to occur. Blood gas analyses on 12 day embryos showed decreased pH at cumulative exposure concentrations greater than 200 ppm. Carbon monoxide in the exhausts probably increased carboxyhemoglobin, reducing buffering capacity. The acidosis was partially compensated by increased HCO3-, Exogenously derived C1-, plus increased HCO3- may shift intracellular K+, making the serum hyperkatremic. Dehydration effects further increased serum hypertonicity.
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Life history and environmental influences on avian incubation and parental care in songbirdsAustin-Bythell, Suzanne H. 13 March 2015 (has links)
Patterns of nest attendance behavior by breeding birds represent a parent-offspring
trade-off in which adults balance self-maintenance with parental care decisions.
Incubation, in particular, is of interest because adults must provide an environment
suitable for embryonic development through nest-building and contact-incubation.
We evaluated how adult incubation constancy and nest visitation rates varied with
life and natural history traits of temperate and tropical bird species. We found that
constancy did not differ by latitude or with nest survival rate. A strong negative
correlation between incubation constancy and egg mass relative to adult body mass
was present. Birds with low constancy tended to have larger relative egg masses
and higher basal metabolic rate. Because adult incubation constancy is relatively
plastic (i.e., varies with ambient temperature), birds with larger relative eggs may
respond to lower cooling rates rather than direct selection for higher or lower
constancy. We then assessed if rates of nest visitation (trips to nests by adults
during incubation and nestling phases) followed the predictions of the Skutch
hypothesis. Skutch suggested that birds nesting in environments with high levels
of nest predation would reduce numbers of trips to their nests so as to minimize the
risk of visual detection by nest predators. We found support for the basic pattern
predicted by Skutch. We also extended his hypothesis to predict other behavior
associated with nesting, such as responses of parents to intruders at the nest.
Despite apparently early departure from the nest site, adults with higher visitation
rates remained conspicuous around the nest site. Thus, while the flight initiation
distance from the human observer was earlier than expected, conspicuousness of
behavior was associated with nest visitation rate. Finally, we assessed how an
environmental variable, photoperiod, might influence rate of embryonic
development in a wild songbird, Sylvia atricapilla. We exposed eggs throughout
the incubation period to daily photoperiods consisting of 4 hours of light and 20
hours of dark (4L), 12 hours light and 12 hours dark (12L), 20 hours light and 4
hours dark (20L) and a skeleton photoperiod with two 1-hour pulses of light that
framed a 20-hour day. We found that the skeleton treatment group differed
significantly from our 4L and 12L, but not the 20L treatment groups. The skeleton
photoperiod accelerated embryonic development. We suggest that photoperiod
may influence incubation period in wild birds and could account for some portion
of the widely observed latitudinal variation in incubation period of songbirds. We
encourage others to assess how photoperiod interacts with parental attendance
patterns to affect embryonic development. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from March 13, 2013 - March 13, 2015
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