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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

The Biological Activation of Fairy Shrimp Cyst Induced by Ultrasound Exposure and Light

Su, Ching-Lin 25 August 2011 (has links)
Fairy shrimp is an anostraca plankton which is raised for watching and scientific study. In recent year, due to the large requirement of fairy shrimp in the market, to increase the hatching rate of fairy shrimp is an important topic. It is found that when an Artemia Cysts hatched by light, the pigment absorption spectra in the Cysts match with the optical wavelength of the experimental incubators. Furthermore, the effect of ultrasound can stimulate the growth or activation of the fairy shrimp, when the ultrasonic parameters of frequency, intensity, exposure time and exposure period are properly controlled in the hatching experiments. This thesis is then focusing on the biological activities to increase the hatching rate of fairy shrimp by light and ultrasound exposure. This work investigates the light effect on the hatching experiment using different wavelength and intensity of LED light; in addition, Cysts is exposed to ultrasound by ultrasonic cleaner and transducer. The resonant frequency of the Cysts is obtained from Rayleig ¡VPlesset bubble activation formula. The radiation of the resonant and non-resonant regions during the hatching experiments are then set up by this resonant frequency for comparison. Finally, according to the experimental results, the correlations of hatching rate with light wavelength, light intensity, resonant frequency and ultrasound intensity are studied by Taguchi Method to understand the play role of the light and ultrasound. The research results show that the hatching rate is 25 % by lamp irradiation, and the maximum hatching rate is 42.5 % by blue light in the light experiment. In ultrasound experiment, the highest incubate percentage, 35 %, is obtained by ultrasound frequency 0.25 MHz and ultrasound intensity 39.2 mW/cm2. In the confirmed test, the blue light plus ultrasound frequency of 0.25 MHz plus ultrasound intensity of 30.9 mW/cm2 can let the incubate percentage up to 48.3%. This is the highest incubate percentage one can get from these experiments. Finally, the results of Taguchi analysis shows that the Confidence level of light affecting the hatching rate is 100%; thus, light source is the most critical factor to affect the hatching procedure. The results of this research can be referred by an endangered species or high economic value of species to increase the rate of hitching.
2

HOW ECOLOGY AND EVOLUTION SHAPE SPECIES DISTRIBUTIONS AND ECOLOGICAL INTERACTIONS ACROSS TIME AND SPACE

Gherghel, Iulian 22 January 2021 (has links)
No description available.

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