published_or_final_version / Mechanical Engineering / Master / Master of Science in Engineering

Living specimens of Cryptomeria japonica D.Don var. radicans Nakai collected in western Japan were analyzed to evaluate the research potential of this tree species for future development of dendrochronology and dendroclimatology in Japan. A sufficiently strong correlation of tree growth with climatic factors was obtained in the residual chronology in which the variance due to autocorrelation was removed. It was also revealed that regional average climatic data are strongly correlated with tree growth. Thus, Cryptomeria japonica appears to have a promising potential for chronology- building and climatic reconstruction in Japan.

This paper presents the synthesis of all the response functions computed on Cedrus atlantica (Endl.) Carrière in Morocco. More than a thousand tree-ring width series collected in 40 sites have been used. At every site, a distinction has been made between young adult trees and old adult trees. Response functions have been calculated on the mean raw ring widths by using the multiple linear regression model of Guiot (Guiot et al. 1982). Among the variables selected to determine the response of Cedrus to climate, the precipitation of autumn and winter and the temperature of January, April, August and September play the leading part in explaining the ring-width variations.

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Graduation date: 1970

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Environmental control of interactions between larval fish and their prey, and the potential influence of this relationship on fish feeding and recruitment, were assessed using empirical models developed using data drawn from the literature and developed in field studies. Ingestion rates of larval fish in laboratory and natural environments were found to differ in relation to food density. In laboratory studies, larvae show a strong functional response to prey density. Larvae situated in situ consume food at much higher races than would be predicted from laboratory studies and these rates are independent of prey density at known in situ densities. This discrepancy between laboratory and field feeding rate-food density relationships can be partly explained by the in situ contribution of small-scale turbulence to predator-prey encounter rates. Field studies of the influence of wind on nearshore hydrography showed that wind-induced upwelling generated favorable combinations of nutrients, light, and small-scale turbulence for production by phyto- and zooplankton. The distribution of microplankton $(<$80 $ mu$m) that resulted from these upwelling episodes was quantitatively described by the cumulative longshore wind velocity during the summer months. Microplankton abundance was greatest within 4 km of a major spawning site for capelin, Mallotus villosus, an economically and ecologically important forage species in the north Atlantic Ocean. Interannual variability in the intensity and frequency of upwelling-favorable winds was positively and significantly correlated with recruitment levels in the NAFO 2J3K capelin population. A new recruitment forecasting model, using an upwelling-related wind index as an input, explained more of the variance in capelin recruitment than did a previously published model. These results suggest that larval capelin are more likely to be food-limited in years when wind conditions are unfavorable for upwelling, and that recruitment in this fi

Sesame (Sesamum indicum L.) is a tropical oilseed found growing in the mid-altitude ($<$1700 m.a.s.l.) regions of Ethiopia. Recently, there has been an attempt by settler farmers from the Ethiopian plateau to expand sesame cultivation in the low altitude areas ($<$800 m.a.s.l.). A genotype-environment interaction study on sesame lines developed through progeny selection originating from a bulk of landraces was carried out at six environments in Ethiopia. The environments selected were believed to provide a wide variation in temperature (altitude), moisture and soil. The objective of the study was, therefore, to select a line or lines widely adaptable over these environments for variables seed yield, oil and protein content as well as fatty acid composition. Two statistical methods, namely, the regression model and the procedural approach of superiority measure were used to estimate line adaptability. Several lines were identified which were adapted over the six environments while others were specifically adapted to low- or high-yielding environments. Lines showing wide adaptation for one variable were not always widely adapted for others. In addition, the two parametric statistics used to analyze the data did not always agree for each variable.

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