Ecological aspects of desert vegetation in relation to a moisture gradient of an ephemeral stream in central Arizona were investigated. The stream channel, flood plain and north, west, south, east facing slopes represent a moisture gradient going from most mesic to most xeric conditions. In parts of the system, vegetation from the stream channel intergraded into flood plain vegetation which in turn intergraded into slope vegetation types. In other areas there are sharp delineations between stream channel and flood plain, and between flood plain and slope. Trees and legumes preferred medium moisture habitats, while forbs, shrubs and succulents preferred the dryer moisture areas. Family groups like the Compositeae and the Gramineae were found to be distributed ubiquitously. Niche widths were broadest for flood plain species. Diversity was highest on the slopes. Negative correlations between diversity and the Synthetic Stand Moisture Index existed, i.e. as moisture increased diversity decreased. It was postulated that factors other than moisture, i.e. disturbance also strongly influenced diversity.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23614号 / 工博第4935号 / 新制||工||1771(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 黒瀬 良一, 教授 花崎 秀史, 教授 岩井 裕 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p> In this thesis the results of optical and scanning electron microscopic investigations of the evaporation morphology of zinc single crystals are presented. Dislocation etch pits developed on (0001) zinc cleavage surfaces. A mechanism is proposed to account for enhanced evaporation at decorated dislocations. The observation of macroledges on pit faces is reported and attributed to impurity-induced bunching of monatomic ledges, the impurities having out-diffused from the bulk. A proposed model for evaporation of faceted surfaces is used to interpret the ledge morphology which developed when samples were evaporated in an oxygen environment. Finally, a correlation between the effects of bulk impurities and gaseous impurities on ledge morphology is demonstrated.</p> / Thesis / Doctor of Philosophy (PhD)

No abstract provided. / Thesis / Master of Science (MSc) / Scope and contents: The probability of fission as a function of primary fragment velocities has been obtained by removing the neutron emission and instrumental dispersions from the velocities determined by Stein with time-of-flight techniques for the thermal neutron fission of u235. Each velocity was increased by 0.69% to make the average kinetic energy per fission agree with the calorimetric value of 167.1 Mev. Excitation energy distributions were obtained by using the primary fragment masses given by Cameron and assuming that the most probable charge distribution for a given mass ratio i s that which leads to the greatest energy release. Evaporation theory was used to determine the number of prompt neutrons emitted. When the excitation energy is divided equally between the fragments and a nuclear temperature of 0.59 Mev is used, the average number of neutrons emitted is 2.95 per fission.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.