Xantusia gracilis

Number of Pages: 2Integrative BiologyGeological Science

First-principles study of the Young's modulus of Si <001> nanowires

We report the results of first-principles density functional theory calculations of the Young's modulus and other mechanical properties of hydrogen-passivated Si nanowires. The nanowires are taken to have predominantly {100} surfaces, with small {110} facets. The Young's modulus, the equilibrium length and the residual stress of a series of prismatic wires are found to have a size dependence that scales like the surface area to volume ratio for all but the smallest wires. We analyze the physical origin of the size dependence, and compare the results to two existing models.Comment: 5 pages, 3 figure

Evaluate and Assess Research Methods in Work Education: Determine if Methods Used to Evaluate Work Education Research are Valid and How Assessment of These Methods is Conducted

This manuscript will compare, research, and comment on how work education experts and practitioners conduct research and evaluations of learning models in today’s modern society. It will measure how valid these practices are and how work education assessment tools are used to determine if learning is taking place. This paper will compare the different paradigms of learning between teaching adults vice teaching children, and give a historical perspective of how these paradigms were developed and modified over the years. The question on whether any of this research is considered useful and valid by educational practitioners will be debated and what experts in the field of work education have determined is worthwhile and should be pursued further. Kirkpatrick’s fourth level of assessment will be introduced as a possible assessment model for evaluation work education research and evaluation. In conclusion the author will give his opinion and suggestions for improving work education research and evaluation methods

Geology of the Sheguiandah Early Man Site: Key Concepts and Issues

The first indication that man was present in Canada well before the final retreat of glacial ice was found at the village of Sheguiandah, on Manitoulin Island, Ontario, in the early 1950s. This paper summarizes the relevant evidence and arguments. The key deposits are two thin layers of diamicton toward the top of the glacial sequence, immediately below a post-glacial level characterized by Paleo-lndian projectile points. The unsorted mixtures of clay, sand and stones contain undisputed quartzite artifacts. These diamictons are considered to be till; alternatives, such as mixing by frost action and mud flows, do not explain their origin. The means by which the artifacts survived the Laurentide glaciation are suggested by the orientation and dip of the pebbles. Apparently diverted from its normal direction of flow by a tough quartzite knob, the ice lacked much erosive power at this point, only transporting the artifacts from one part of the site to another. Geological interpretation indicates that man made the artifacts now found in the tills during Early Wisconsinan interstadials. Other evidence, in the form of prehistoric quarries, pollen analyses and radiocarbon dating, supports the published age estimate of more than 30,000 years BP.Géologie du site préhistorique de Sheguiandah: problèmes et résultats obtenus. Le premier indice de la présence de l'homme au Canada avant le retrait définitif des glaciers a été découvert à Sheguiandah, dans l'île de Manitoulin en Ontario, au début des années 50. On rassemble ici les principales preuves et les arguments en faveur de cette présence. Les principaux dépôts consistent en deux minches couches de diamicton sus-jacentes à une séquence glaciaire et sous-jacentes à un niveau postglaciaire contenant des pointes de projectiles paléoindiens. Les dépôts, composés d'un mélange d'argile, de sable et de cailloux, contiennent indiscutablement des objets témoins de quartzite. On considère ces diamictons comme étant des tills. D'autres explications, comme l'action du gel et la solifluxion ne rendent pas compte de leur origine. L'orientation et l'inclinaison des galets expliquent la présence des objets témoins, malgré le passage des glaciers. Il semble que le glacier, probablement détourné de son cours par une bosse de quartzite très dur, ne fit que transporter les objets d'une partie du site à une autre. Selon les données géologiques, il semble que les objets aient été fabriqués au cours d'interstades qui ont précédé le Wis-consinien supérieur. D'autres preuves, comme la présence de carrières, l'analyse pollinique et une datation au radiocarbone, corroborent la valeur de la date estimée à plus de 30 000 BP.Der erste Hinweis auf menschliches Leben in Kanada lang vor dem Rùkzug des glazialen Eises wurde im Dorf von Scheguiandah gefunden, auf der Insel Manitoulin, Ontario, in den frùhen fùnfziger Jahren. Dieser Artikel faBt die relevanten Anhaltspunkte zusammen. Die wichtigsten Ablagerungen sind zwei dùnne Schichten von Diamikton in Richtung der Spitze der glazialen Sequenz und direkt unterhalb eines postglazialen Niveaus, welches Spitzen von Paleo-indianischen Wurfgeschossen enthâlt. Die ungeordneten Mischungen aus Lehm, Sand und Steinen enthalten unbestreitbar Artefakte aus Quartz. Man halt dièse Diamiktons fur Grundmorànen ; Alternativen, wie z.B. Mischung durch Frosteinwirkung und Schlammstrôme, erklàren ihre Entstehung nicht. Die Orientierung und Neigung der Kiesei lassen vermuten, wie dièse Artefakte die Laurentische Eiszeit ùberlebten. Das Eis wurde offensichtlich von seiner normalen FluRrichtung durch eine harte Quartz -Kuppe abgelenkt und verlor an dieser Stelle sehr viel Erosionskraft, so daf3 es die Artefakte am Fundort nur von einer Stelle zur anderen trug. Die geologische Interpretation zeigt, dafî der Mensch dièse jetzt in den Grundmorànen gefundenen Artefakte wàhrend der Interstadiale, die dem spàten Wisconsin vorausgingen, angefertigt hat. Andere Beweise, wie prahistorische Steinbrùche, Pollenanalysen und Radiokarbondatierungen stùtzen die auf mehr als 30.000 Jahre v.u.Z. geschatzte Datierung