The small-signal speed of sound in humid air is calculated from a model which includes the real-gas effects from the equation of state for humid air and the vibrational dispersion due to N2, O2, and CO2 relaxation. Other atmospheric effects such as dispersion due to viscothermal and rotational relaxation, heat radiation, propagation along the air-ground boundary, the density gradient, turbulance, aerosols and fogs are considered and found to be unimportant for frequencies between 1Hz and 5 HHz at one atmosphere. The uncertainty in predicting the sound speed varies between 0. Experimental results in humid air at 20C and 30C are in excellent agreement with the model. For the propagation frequency of 20 Hz, it is found that the presently used sound-ranging formula, c – A correction to the “sonic” temperature determination is suggested with results in deviations of less than 0. For over a century, various neuroanatomical measures have been employed as assays of cognitive ability in comparative studies.
Ice-sheet dynamics Sampling the surface of Taku Glacier in Alaska. There is increasingly dense firn between surface snow and blue glacier ice. An ice core is a vertical column through a glacier, sampling the layers that formed through an annual cycle of snowfall and melt.
Under the direction of Dr. Jim Feathers, this laboratory provides dating service for ceramics, lithics, and sediments using optically-stimulated luminescence (OSL) and thermoluminescence (TL). This allows researchers to date materials that cannot be dated using other techniques (e.g., lack of suitable organic remains for radiocarbon dating).
One theory is that the name of the Palus tribe spelled in early accounts variously as Palus, Palloatpallah, Pelusha, etc. Traditionally, the Palouse region was defined as the fertile hills and prairies north of the Snake River , which separated it from Walla Walla County, and north of the Clearwater River , which separated it from the Camas Prairie , extending north along the Washington and Idaho border, south of Spokane , centered on the Palouse River.
This region underwent a settlement and wheat-growing boom during the s, part of a larger process of growing wheat in southeast Washington, originally pioneered in Walla Walla County south of the Snake River. This larger definition is used by organizations such as the World Wide Fund for Nature , who define the Palouse Grasslands ecoregion broadly.
Nevertheless, the traditional definition of the Palouse region is distinct from the older Walla Walla region south of the Snake River, where dryland farming of wheat was first proved viable in the region in the s. During the s, the Walla Walla region was rapidly converted to farmland, while the initial experiments in growing wheat began in the Palouse region, which previously had been the domain of cattle and sheep ranching. When those trials proved more than successful, a minor land rush quickly filled the Palouse region with farmers during the s.
The simultaneous proliferation of railroads only increased the rapid settlement of the Palouse. By nearly all the Palouse lands had been taken up and converted to wheat farming. Colfax the oldest , Palouse , Pullman , and on the Idaho side, Moscow. These four centers, along with at least ten lesser ones, resulted in a diffuse pattern of rural centers, relative to the centralized Walla Walla county.
Luminescence Dating Laboratory
Volume 27, Issues 5—6 , 5 December , Pages Luminescence dating: Wintle Show more https: Laboratory procedures for dating sediments have been adapted from those for pottery and new procedures have been developed as the need arises. The majority of sediment dating applications are carried out on quartz and potassium-rich feldspars and the general characteristics of the TL and OSL signals from these minerals are reviewed.
For sediments some new problems were encountered, with some grains perhaps not being completely bleached at deposition. For OSL signals there is no simple procedure for the selection of a thermally stable signal, as there had been in the case of pottery.
U of A anthropologist Willoughby believes that the items found prove continuous occupation of the areas over the last , years, through what is known as the “genetic bottleneck” period of the last ice age.
Giant handaxes suggest that different groups of early humans coexisted in ancient Europe February 23, by Martina Demuro, Lee Arnold And Mathieu Duval, The Conversation Researchers work on the archaeological site in Spain, known as Porto Maior, where the tool deposits were found. An exceptionally high density of giant handaxes dated to , , years ago has been uncovered at an archaeological site in Galicia, northwest Spain. The findings are documented in a new article published by our international research team of archaeologists and dating specialists.
The discovery of these handaxes suggests that alternative types of stone tool technologies were simultaneously being used by different populations in this area — supporting the idea that a prehistoric “Game of Thrones” scenario existed as Neanderthals emerged in Europe. Additional evidence for this idea comes from fossil records showing that multiple human lineages lived in southwest Europe around the same time period. The archaeological site at Porto Maior preserves an ancient stone tool culture known as the Acheulean.
Characterised by symmetrically knapped stones or large flakes known as bifaces , the Acheulean is the first sophisticated handaxe technology known in the early human settlement record of Europe. While Acheulean sites are widespread across the continent, Porto Maior represents Europe’s first extensive accumulation of large cutting tools LCTs in the Acheulean tradition.
The thermoluminescence technique is the only physical means of determining the absolute age of pottery presently available. It is an absolute dating method, and does not depend on comparison with similar objects as does obsidian hydration dating, for example. Most mineral materials, including the constituents of pottery, have the property of thermoluminescence TL , where part of the energy from radioactive decay in and around the mineral is stored in the form of trapped electrons and later released as light upon strong heating as the electrons are detrapped and combine with lattice ions.
By comparing this light output with that produced by known doses of radiation, the amount of radiation absorbed by the material may be found. When pottery is fired, it loses all its previously acquired TL, and on cooling the TL begins again to build up. Thus, when one measures dose in pottery, it is the dose accumulated since it was fired, unless there was a subsequent reheating.
martindale’s calculators on-line center archaeology, anthropology, paleoichnology – palaeoichnology – neoichnology, paleobiology – palaeobiology, paleobotany – palaeobotany, paleoclimatology – palaeoclimatology.
Chronological Methods 12 – Luminescence Dating Scientists in North America first developed thermoluminescence dating of rock minerals in the s and s, and the University of Oxford, England first developed the thermoluminescence dating of fired ceramics in the s and s. During the s and s scientists at Simon Frasier University, Canada, developed standard thermoluminescence dating procedures used to date sediments.
In , they also developed optically stimulated luminescence dating techniques, which use laser light, to date sediments. How does Luminescence work? The microscopic structure of some minerals and ceramics trap nuclear radioactive energy. This energy is in constant motion within the minerals or sherds. Most of the energy escapes as heat, but sometimes this energy separates electrons from the molecules that make up the minerals or ceramics.
Usually the electrons will reconnect with the molecules, but some will not. The electrons that dont reconnect eventually encounter imperfections in the microscopic structure of the ceramics or minerals, and they become trapped by these imperfections. Over time energy in the form of more and more trapped electrons is stored in these structural imperfections. By heating the ceramic or mineral to above degrees Celcius, these trapped electrons are released, creating a flash of light called thermoluminescence.
When a laser light source is used to stimulate the release of electrons, the process is called optically stimulated luminescence.
UW Luminescence Laboratory
City of Hope Beckman Research Institute Small Animal Imaging East Duarte Road Duarte, CA Preliminary testing in laboratory animals has long been essential to the development of new pharmaceuticals and of new methods for the treatment of human disease. The current development of sophisticated transgenic animal models—coupled with a growing recognition of the importance of understanding of disease processes in the context of the living host—has extended the use of animal experimentation beyond safety and efficacy testing into the realm of mechanistic investigation.
Thanks to non-invasive imaging, researchers can now perform multiple measurements, over time, in the same animal. This development not only enhances data quality in studies of dynamic molecular and of physiologic processes—it greatly reduces the number of animals required for such studies. With the help of this extraordinary technology, the dynamic biodistribution of therapeutic agents as well as vital processes, such as gene expression, cell trafficking, cell viability, cell proliferation, tissue hypoxia, and angiogenesis can be monitored non-invasively in the intact animal.
Imaging of small animals has become indispensable to medical research and to scientific developments, as it helps investigators remain competitive for extramural funding.
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A Twa hunter-gatherer in Uganda climbing a tree to gather honey. Nathaniel Dominy Early Human Ancestors May Have Walked AND Climbed for a Living Africa 31 December The results of recently conducted field studies on modern human groups in the Philippines and Africa are suggesting that humans, among the primates, are not so unique to walking upright as previously thought. The findings have implications for some of our earliest possible ancestors, including the 3.
Associate professor of anthropology Nathaniel Dominy of Dartmouth College, along with colleagues Vivek Venkataraman and Thomas Kraft, compared African Twa hunter-gatherers to agriculturalists living nearby, the Bakiga, in Uganda. In the Philippines, they compared the Agta hunter-gatherers to the Manobo agriculturalists. They found that the Twa and the Agta hunter-gatherers regularly climbed trees to gather honey, an important element in their diets.
More specifically, they observed that the climbers “walked” up small trees by applying the soles of their feet directly to the trunk and progressing upward, with arms and legs advancing alternately. To do this successfully, they said, required extreme dorsiflexion, or bending the foot upward toward the shin to a degree not normally possible among most modern humans. They tested their hypothesis by conducting ultrasound imaging of the fibers of the large calf muscles of individuals in all four groups.
The results showed that the Agta and Twa tree-climbers had significantly longer muscle fibers than those of their agricultural counterparts and other “industrialized” modern humans. It demonstrated that a foot and ankle bone structure adapted primarily for walking upright on land does not necessarily exclude climbing as a behaviorally habitual means of mobility for survival.
The implications for our possible early human ancestors, such as the species Australopithecus afarensis, are significant. Australopithecus afarensis is an extinct hominid that lived between 3.
References for the Native American Flute
History[ edit ] Bretz conducted research and published many papers during the s describing the Channeled Scablands. Bretz’s theories met with vehement opposition from geologists of the day, who tried to explain the features with uniformitarian theories. Pardee first suggested in to Bretz that the draining of a glacial lake could account for flows of the magnitude needed.
Aberystwyth Luminescence Dating Laboratory. The Sheffield Centre for International Drylands Research (SCIDR), England. Center for Applied Dosimetry. Archaeometry Research Group Heidelberg, Germany. The University of Washington Luminescence Dating Laboratory. References Aitken, Martin J. Thermoluminescence Dating.
This list is by no means complete or exhaustive. Chase Organizer in press for , April. Discovery-based STEM learning 2. Are we there yet? In Proceedings of the Winter Simulation Conference. Enzymatic and detrital influences on the structure, function, and dynamics of spatially-explicit model ecosystems.
Journal of Policy Analysis and Management.
Electrical, Electronic and Cybernetic Brand Name Index
Stratigraphic unit numbers are shown on the left, and the cultural horizons are highlighted in gray. Clovis ages have been reported elsewhere see text. No HF etching was applied. An initial equivalent dose De estimate was made by comparing the natural OSL signal of four aliquots to their OSL signal after a given dose.
Introduction. Please note that most of these Brand Names are registered Trade Marks, Company Names or otherwise controlled and their inclusion in this index is strictly for information purposes only.