Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 197 for “"Frogs"”.
-
Metabolism of Frogs in Relation to Season
Made available in DSpace on 2014-12-05T22:14:32Z (GMT). No. of bitstreams: 1 0009070.pdf: 4517703 bytes, checksum: 9095a93a3cf506d51870b9debc6afa37 (MD5) Previous issue date: 1954
-
Evolutionary relationships of the discoglossoid frogs - osteological evidence
The discoglossoid Frogs (Discoglossidae and Leiopelmatidae) are generally considered to be the most primitive of the living frogs. Previous authors have grouped them on the basis of common possession of a limited number of primitive features of little phylogenetic significance, leaving the question …
-
Control of mechanically stable movement by spinalized frogs
… performance advantages. Previous work in frogs and cats has shown that the isometric forces measured during movements evoked by intraspinal stimulation converge to a stable equilibrium. In non-isometric conditions, however, there is no guarantee that a similar property of convergence will …
-
Monitoring amphibian populations and the status of wood frogs and boreal chorus frogs in the Kawuneeche Valley of Rocky Mountain National Park
… masses as a state variable for monitoring wood frogs and other pond-breeding amphibians. Specifically, I assessed patterns of detectability in wood frog egg masses and evaluated the statistical power of using counts of egg masses and linear regression to detect trends. In Chapter 1, I used …
-
VISUAL RECOGNITION OF THE STATIONARY ENVIRONMENT IN LEOPARD FROGS
Leopard frogs (Rana pipiens) rely on vision to recognize behaviorally meaningful aspects of their environment. The optic tectum has been shown to mediate the frog's ability to recognize and respond to moving prey and looming objects. Nonetheless, atectal frogs are still able to appropriately …
-
Locomotion of Skittering Frogs at the Air-water Interface
… investigate both of these forms of locomotion in frogs. First we quantified the kinematics of skittering, jumping on top the water's surface without sinking, in two species of frog, Acris crepitans and Euphlyctis cyanophlyctis. We found that what was described as "skittering" locomotion in Acris …
-
Ontogeny and evolutionary morphology of the skeleton in frogs
… and the evolution of skeletal morphology in frogs. In the first part of this dissertation, I examine the evolution of skull development in pipoid frogs, a group that is exceptional in both morphology and life history. Two methods are used. First, skull bone ossification sequences are examined …
-
Population Genomic And Phenotypic Diversification In African Reed Frogs
… responses to these shared global events. Reed frogs (Hyperoliidae) are an ideal group for asking questions about broad-scale patterns of diversification because there are over 200 species broadly distributed throughout sub-saharan Africa in rainforest, bushland and savannah habitats and there …
-
Tuning of the middle ear in túngara frogs ( Engystomops pustulosus)
… well in the frequency range of their calls. In frogs, body size is a major predictor of both the dominant frequency of the mating call, and the frequency of best sensitivity of the ear, which tend to match each other. Various pathways are known to receive sound in frogs. Eardrums receive …
-
Identification, characterisation and design of bioactive peptides from Chinese frogs
… is an AMP type found in skin secretions of frogs from the family Ranidae, In Chapter 3, a novel temporin family peptide, QUB1434, was identified from Pelophelax plancyi fukienensis. it exhibited strong activity against Gram-positive bacteria but no effect on Gram-negative bacteria. A series …
-
Patterns and processes of speciation in North American chorus frogs (Pseudacris)
… resulting from this process in the chorus frogs (Pseudacris). I first lay the foundation for this work by constructing phylogenies based on molecular data. I then address broad-scale questions regarding the abiotic factors thought to drive speciation. I examine evolution of reproductive …
-
Novel bioactive peptides from the defensive skin secretion of Phyllomedusinae frogs
Amphibian skin secretion contains a variety of bio-components, of which bioactive peptides are predominant. They produce such peptides to protect themselves from the threats in their environment like predatory attack and microorganism invasion. Antimicrobial peptides (AMPs) act as the first line of …
-
Dissecting frogs: The effect of humorous political advertisements on candidate evaluations
This dissertation examines the role of humor in political campaigns, with a primary focus on candidate evaluations. The use of humor by candidates in campaigns, though widespread in the political arena, has been largely ignored by mainstream political science. This neglect is unfortunate because of …
-
Cellular and molecular characterization of the corneal epithelium in Xenopus frogs
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-12-01
-
Micromanaging Freeze Tolerance: The Biogenesis and Regulation of microRNAs in Frozen Frogs
When temperatures plummet below 0°C, the wood frog (Rana sylvatica) freezes up to 65% of its body water in extracellular ice masses, displaying no measurable brain activity, no breathing, and a flat-lined heart. Various molecular mechanisms including microRNAs, a multifunctional group of short …
-
Seasonal movements of western chorus frogs (Pseudacris triseriata triseriata) tagged with radioactive cobalt
The movements of Western Chorus Frogs (Pseudacris, triseriata triseriata) were studied from March, 1970, to March, 1971, at the Robert H. and Esther L. Cooper Woodland Area near Muncie, Delaware County, Indiana. The objectives of the study were to determine: (1) the time and rate of dispersal from …
-
Bioactive peptides from the defensive skin secretions of selected American and Asian frogs
For thousands of years, habitats of amphibians have changed dramatically from the initial marine to current freshwater aquatic types. This transition provided diverse resources but presented significant challenges from the environment and from predators. As a consequence, amphibians adapted to …
Page 1 of 10