• 41Ca Concentrations in Modern Bone and Their Implications for Dating

      Middleton, Roy; Fink, David; Klein, Jeffrey; Sharma, Pankaj (Department of Geosciences, The University of Arizona, 1989-01-01)
      We have made the first measurements without pre-enrichment of 41Ca in terrestrial rock and bone samples using accelerator mass spectrometry. Although the results in tufa deposits from Egypt are in good agreement with the saturation value of 8 x 10^-15 predicted by Raisbeck and Yiou (1979), the average 41Ca:40Ca ratio of 2x10^-15 (range: 0.6 to 4.2x10^-15) that we measure in modern bone is an order of magnitude lower than that obtained previously by Henning, et al (1987) on a cow bone that was measured using AMS following isotope enrichment. The low value and the variability (more than a factor of seven) of the 4 Ca:40Ca ratio in modern bone make the possibility of dating bones using 41Ca unlikely.
    • 42 Nutritional Education Aides Teach Arizona Families to Eat Better Cheaper

      College of Agriculture, University of Arizona (Tucson, AZ), 1980
    • 433 Eros: Problems with the meteorite magnetism record in attempting an asteroid match

      Wasilewski, P.; Acuña, M. H.; Kletetschka, G. (The Meteoritical Society, 2002-01-01)
      The Magnetometer experiment (MAG) onboard the NEAR-Shoemaker spacecraft detected no global scale magnetization and established a maximum magnetization of (2.1x10^(-6) Am^2 kg^(-1)) for asteroid 433 Eros. This is in sharp contrast with the estimated magnetization of other S-class asteroids (Gaspra ~ 2.4 x 10^(-2) Am^2 kg^(-1), Braille ~ 2.8 x 10^(-2) Am^2 kg^(-1) and is below published values for all types of ordinary chondrites. This includes the L/LL types considered to most closely match 433 Eros based on preliminary interpretations of NEAR remote geochemical experiments. The ordinary chondrite meteorite magnetization intensity data was reviewed in order to assess the reasonableness of an asteroid - meteorite match based on magnetic property measurements. NRM (natural remanent magnetization) intensities for the ordinary chondrite meteorites show at least a 2 order of magnitude range within each of the H,L,LL groups, all well above the 2.1 x10^(-6) Am^2 kg^(-1) level for 433 Eros. The REM values (ratio of the NRM to the SIRM (saturation remanent magnetization)) range over 3 orders of magnitude for all chondrite groups indicating no clear relationship between NRM and the amount of magnetic material. Levels of magnetic noise in chondrite meteorites can be as much as 70% or more of the NRM. Consequently published values of the NRM should be considered suspect unless careful evaluation of the noise sources is done. Goddard studies of per unit mass intensities in large (> 10,000gm) and small (down to 1 gm) samples from the same meteorite demonstrate magnetic intensity decreases as size increases. This would appear to be explained by demagnetization due to magnetic vector randomness at unknown scale sizes in the larger samples. This would then argue for some level of demagnetization of large objects such as an asteroid. The possibility that 433 Eros is an LL chondrite cannot be discounted.
    • 44-WR, Arizona's Wilt Resistant Cotton

      Pressley, E. H.; Plant Breeding Department (College of Agriculture, University of Arizona (Tucson, AZ), 1956)
    • 44th Annual Meeting of the National Wildlife Federation

      Kimball, Thomas L. (Society for Range Management, 1980-10-01)
    • 48 Reasons Why Land and Water Resources Are Being Neglected

      Pederson, Oscar; Wirak, Joe (Society for Range Management, 1980-08-01)
    • 5.2-5.8 ka BP Paleoenvironment of the Southern Slope of Mount Raizan, Japan

      Okuno, Mitsuru; Nagaoka, Shinji; Hase, Yoshitaka; Mori, Yuichi; Konomatsu, Masahiko; Takahashi, Toshihiko; Nakamura, Toshio; Nishida, Tamio (Department of Geosciences, The University of Arizona, 2001-01-01)
      Accelerator mass spectrometry (AMS) radiocarbon dating and paleoecological analysis of slope deposits at Mt Raizan provided seven 14C dates indicating that landslides occurred in that area at 6.0 to 6.3 cal ka BP and 6.5 cal ka BP. Plant macrofossils, pollen grains, and spores point to a mixed forest at that time, consisting of conifers and broad-leaved trees. On the other hand, insect fossil indicates slightly colder climate than that of the flora. This difference may be attributed to varied sensitivities of each proxy to climatic changes.
    • 50 Bulls Entered in UA Gain-Test Trails

      College of Agriculture, University of Arizona (Tucson, AZ), 1963
    • A 548-Year Tree-Ring Chronology Of Oak (Quercus Spp.) For Southeast Slovenia And Its Significance As a Dating Tool And Climate Archive

      Čufar, Katarina; Luis, Martín De; Zupančič, Martin; Eckstein, Dieter; University of Ljubljana, Biotechnical Faculty, Dept. of Wood Science and Technology, Rozˇna dolina, Cesta VIII/34, SI-1000 Ljubljana, Slovenia; University of Zaragoza, Dept. Geografı´a y O.T., C/Pedro Cerbuna 12, E-50009 Zaragoza, Spain; University of Hamburg, Dept. of Wood Science, Division Wood Biology, Leuschnerstr. 91, D-21031 Hamburg, Germany (Tree-Ring Society, 2008-06)
      Tree-ring series of oak, from both living trees (Quercus petraea and Q. robur) and historic timbers in southeastern Slovenia were assembled into a 548-year regional chronology spanning the period A.D. 1456–2003. It is currently the longest and the most replicated oak chronology in this part of Europe located at the transition between Mediterranean, Alpine and continental climatic influence. The chronology correlated significantly with regional and local chronologies up to 700 km away in Austria, Hungary, Serbia, Czech Republic and southern Germany. It also showed good ‘‘heteroconnection’’, i.e. agreement with chronologies of beech (Fagus sylvatica), ash (Fraxinus excelsior) and silver fir (Abies alba) in Slovenia. A preliminary dendroclimatic analysis shows that precipitation and temperature in June accounted for a high amount of variance (r250.51) in the tree-ring widths. The chronology thus contains considerable potential as a climate archive. We also present its use as a tool for the dating of wooden objects of the cultural heritage. Moreover, the chronology can be a point of reference for building tree-ring chronologies in neighboring regions.
    • 62 Young Sires in Gain Tests at UA Station

      College of Agriculture, University of Arizona (Tucson, AZ), 1967
    • 65th Annual SRM Meeting, February 2012, Spokane, Washington

      Buckhouse, John (Society for Range Management, 2011-04-01)
    • 70 Languages Equal and Free: The Legal Status of Minority Languages in the Soviet Union [Article]

      Weiner, Richard E. (The University of Arizona James E. Rogers College of Law (Tucson, AZ), 1989)
    • A 7104-Year Annual Tree-Ring Chronology for Bristlecone Pine, Pinus Aristata, from the White Mountains, California

      Ferguson, C. W. (Tree-Ring Society, 1969-08)
      A 7104-year tree-ring chronology has been developed for bristlecone pine, Pinus aristata Englem., in the White Mountains of east-central California, U.S.A. The chronology was extended backward in time by incorporating tree-ring series from living trees up to 4600 years old, as well as from standing snags, fallen trees, large remnants, and eroded fragments. The availability of datable wood in the 9000-year range has been indicated by radiocarbon analysis. Aspects of chronology development are described. Substantiating evidence, for both age and chronology, is derived from the bristlecone pine of east-central Nevada, where a 5000-year series has been developed. Dated bristlecone pine has been used in radiocarbon studies; approximately 500 samples of dated wood have been sent to various laboratories.
    • 7th International Conference on Accelerator Mass Spectrometry

      Department of Geosciences, The University of Arizona, 1995-01-01
    • 7th International Conference on Accelerator Mass Spectrometry

      Department of Geosciences, The University of Arizona, 1994-01-01
    • 7th International Conference on Accelerator Mass Spectrometry

      Department of Geosciences, The University of Arizona, 1994-01-01
    • 7th International Conference on Accelerator Mass Spectrometry

      Department of Geosciences, The University of Arizona, 1995-01-01
    • An 800-Year Douglas Fir at Mesa Verde

      Schulman, Edmund (Tree-Ring Society, 1947-07)