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.
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Showing 1 to 20 of 62 for “"Chemical signals"”.
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Waterhole Dynamics and Chemical Signals of African Elephants (<i> Loxodonta Africana </i>)
… communication in elephants, often via chemical signals. This study also determined behaviorally via biological assays (June 2006-June 2007) whether four known insect pheromones identified in the ovulatory urine of African elephants serve as sex-specific pheromones. When tested singly, …
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Physical regulation of epiphyseal cartilage biosynthesis : responses to electrical, mechanical, and chemical signals
Thesis (Ph. D.)--Massachusetts Institute of Technology, Harvard-MIT Division of Health Sciences and Technology Program in Medical Engineering and Medical Physics, 1986.
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Biogeographic Patterns, Predator Identity, and Chemical Signals Influence the Occurrence and Magnitude of Non-lethal Predator Effects
… Carcinus maenas (Linnaeus, 1758). Nucella use chemical cues emanating from their most common predator (Carcinus maenas) and crushed conspecifics to evaluate predation risk. Nucella from different habitats experience different levels of predation risk, and Nucella from habitats with high levels …
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Electrochemical and Magnetochemical Approaches for Neuronal Modulation
The development of tools to deliver chemical signals to specific neurons can enhance our understanding of chemical signaling in the nervous system and enable chemical therapies for neurological disorders. Existing technologies for chemical neuromodulation, including intracranial injection of …
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Patterns of Chemosensory Behavior in a Closed Population of Wild African Elephants (Loxodonta Africana)
… are used by many mammalian species to assess chemical signals in the environment. These chemical signals may contain important information about reproductive state, identity, status, or location of conspecifics. Elephants are a long-lived species and males reproduce at a much later age than …
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Assessment of magic angle spinning spectroscopy for studying migration in solid milk chocolate
… deliver diffusion data specific to individual chemical species. Using a Bruker 300 MHz spectrometer equipped with liquid state and hr-MAS probes various spectroscopic characteristics of a milk chocolate sample were recorded. The MAS spectrometer resolved the chocolate spectrum into individual …
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Pheromones in entomopathogenic nematodes: effects on dispersal and reproductive behaviours
… effects). I investigate both sex pheromones and chemical signals produced by and affecting the infective juvenile (IJ) stage. In this thesis, I both test central hypotheses, and attempt the identification of key pheromone components, using assay-guided fractionation. As lethal parasites of …
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Chemomechanics of self-oscillating gels
… stimuli into propagating electrical and chemical signals throughout the body. Few synthetic materials have been engineered to produce communicative chemical signals in response to mechanical input, though such synthetic material analogues could enable devices that mimic biological tissues …
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The behavioural function of pheromones in crayfish
… efficiency for population control, however the chemical identity of crayfish pheromones is unknown. An incomplete understanding of chemical communication has delayed progress in the development of appropriate bioassays. This thesis therefore focused on researching the natural context of chemical …
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Making Scents of Butterfly Pheromone Evolution
Insect chemical profiles are diverse and complex, reflecting the wide range of functions they serve. Volatile compounds are used in foraging, defence, and mating, and pheromones are particularly important to the lives of insects. These are chemical signals that mediate the behaviour of …
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Piezo1-dependent mechanical regulation of chemical signalling in the developing Xenopus laevis brain
… correct targets by various chemo-mechanical signals. Major chemical signals include semaphorins, slits, netrins and ephrins/Eph, whereas mechanical signals include tissue stiffness, viscosity and cellular forces. In the developing embryo, chemical and mechanical signals are not isolated. …
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Development of an in vitro model of contraction by fibroblasts
… to the formation of scar. The mechanical and chemical signals, which control the contraction, are being investigated through the use of models of fibroblast contraction to understand the conditions which promote tissue regeneration. A cell force monitor (CFM) was designed and constructed to …
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Chemosensory Behavior and Development of African Male Elephants (Loxodonta Africana)
… and search for mates when mature. Urinary chemical signals play an important role in detecting reproductively active females. African male elephants develop movement, social and chemosensory behaviors over four major life changes. The first goal of this study was to compare behavior among …
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Regulation and production of extracellular signaling molecules in Bacillus subtilis
Many bacteria use chemical signals for intercellular communication. These signals accumulate extracellularly and are sensed at threshold concentrations to alter gene expression. Bacillus subtilis uses cell-cell signals to control genetic competence, sporulation, degradative enzyme production and …
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A Two-Component Model For Bacterial Chemotaxis
… is the directed cell movement in response to chemical signals. It iscrucial in many multicellular processes, such as wound healing, cancer metastasis,embryonic development and bioremediation. Quantitative descriptions of chemotaxiswill lead to a better understanding of the mechanisms of …
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Age Effects on Social and Investigative Behaviors in a Closed Population of African Elephants
… the approach to a waterhole, investigation of chemical signals differed by age and sex. The social dominance hypothesis was supported by the proportion of snuffs performed to feces, while the average rate of sniffs supported the reproductive success hypothesis. Social behaviors chnaged between …
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Crayfish Predation on Juvenile Freshwater Mussels (Bivalvia: Unionidae)
… animals are capable of detecting water-borne chemical cues from predators and will decrease movement in order to avoid predation. Both horizontal and vertical movement of mussels decreased when exposed to water that contained or had previously contained crayfish. When crayfish cues were …
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Quantifying effects of substrata chemomechanical properties on eukaryotic and prokaryotic cell adhesion and morphology
… are capable of processing both mechanical and chemical signals from the extracellular environment. Exactly how these two factors affect the cell biology in the context of physiological circumstances is an area of intense interest that has given rise to an entire field of study called cell …
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Highly Integrated Graphene-Based Chemical Sensing Platform for Structural Monitoring Applications
… channel to be readily modulated in response to chemical changes in proximity to its surface, effectively converting chemical signals into the electrical domain. However, their utilization has been constrained due to variations in device-to-device performance arising from synthesis and …
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Communication in the hymenoptera : chemistry, ecology and evolution
… exhibit complex systems of communication with chemical signalling being the most important mode. Although there are many studies on chemical communication in insects, the evolution of chemical signals is not well understood. Due to the conflict of interests between individuals, different …
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