Now showing items 12757-12776 of 20709

    • Packaging: Can It Boost Sale of Eggs?

      Pasvogel, M. W.; Department of Poultry Science (College of Agriculture, University of Arizona (Tucson, AZ), 1958)
    • Packard Instrument Company Radiocarbon Dates I

      Kowalski, Sandra J. (American Journal of Science, 1965-01-01)
    • Packard Instrument Company Radiocarbon Dates II

      Kowalski, Sandra J.; Schrodt, Ariel G. (American Journal of Science, 1966-01-01)
    • Packhorse grazing behavior and immediate impact on a timberline meadow

      Olson-Rutz, K. M.; Marlow, C. B.; Hansen, K.; Gagnon, L. C.; Rossi, R. J. (Society for Range Management, 1996-11-01)
      Recreational packhorse grazing is one of many uses of high elevation wildland meadows. We quantified the behavior of horses grazing on an upper timberline meadow in southwestern Montana and the immediate impact on the plant community. Horses were picketed on 15-m diameter circles for different durations (0, 4, 8, 18 hours), months (July, August, September), and frequencies (1 month only, all 3 months) over 3 summers. We recorded the amount of time horses spent grazing or resting, horse movement while grazing, plant height, and grazed plant frequency before and after grazing. Grazing was the dominant activity throughout the trial. After an initial 3-4 hour feeding bout, horses continued to graze intermittently. When not grazing, horses rested more than walked. Horses grazed a higher percent of grasses at first (4 hour picket duration) but the percent of fortes grazed increased with increased time on picket. After 18 hours of use, or after repeated use on the same picket circle through the summer, more than 50% of the grasses and 20% of the fortes bad been grazed and tallest plant material was less than 12 cm tall. Recreational packhorse management should include previous training (picket grazing experience), limiting time on specific circles to 8 hours or less, and using picket circles only once each season.
    • Paddock shape effects on grazing behavior and efficiency in sheep

      Sevi, A.; Muscio, A.; Dantone, D.; Iascone, V.; D'Emilio, F. (Society for Range Management, 2001-03-01)
      Two grazing trials were conducted during early winter (December 1996-January 1997) and spring (April-May 1997) to evaluate the effect of shape of pasture on forage use and behavior of grazing sheep (Ovis aries). Two treatments were tested, square and rectangular paddock, with 2 replicates for each treatment of 9 ewes each. Groups were homogeneous for age and weight. Paddock size furnished 10 m2 per sheep per day. Each paddock was divided into 8 equal plots to determine herbage intake and grazing efficiency along the boundary and in the middle of paddocks. The shape of paddock affected sheep grazing efficiency and herbage intake both in the winter and in the spring. Because of a greater amount of herbage destroyed within boundary plots, the ewes in rectangular paddocks grazed less time, had lower herbage intake and used forage less efficiently than ewes in square paddocks. These results suggest that the shape of pasture can affect the behavior and herbage intake of sheep grazing in small paddocks and indicate that square paddocks should be used for research studies on sheep grazing behavior.
    • Paddock Size and Stocking Density Affect Spatial Heterogeneity of Grazing

      Barnes, Matthew K.; Norton, Brien E.; Maeno, Motoko; Malechek, John C. (Society for Range Management, 2008-07-01)
      The claim that intensive rotational grazing (IRG) can sustain higher stocking rates can be partially explained by more even spatial distribution of grazing such that livestock consume forage from a greater proportion of a pasture. To test the hypothesis that utilization is more even at the higher stocking densities of smaller paddocks, mean absolute deviation (heterogeneity) of utilization estimates by plot was compared in paddocks of sizes and stocking densities representing increasing subdivision from two-paddock deferred rotation grazing (DRG) to 16-, 32-, and 64-paddock, two-cycle IRG. These 70-, 4-, 2-, and 1-ha paddocks were grazed for 7 wk, 4 d, 2 d, and 1 d, respectively, at 32 animal unit days (AUD) ha-1 during 2000 and 34 AUD ha-1 during 2001. Within IRG there was no response to the treatment gradient. After one cycle in the IRG paddocks, heterogeneity of use was generally lower than in the DRG paddocks, in both 2000 (3-11% [outlier 18%] vs. 14-19%) and 2001 (9-17% vs. 24-28%). After a second cycle in 2001, heterogeneity in half of the IRG paddocks (17-21%) was nearly as high as the early-grazed (24%), but not the late-grazed (28%), of the DRG paddocks. This lack of a stronger difference between systems was probably due to the fixed two-cycle IRG schedule and lack of plant growth during the nongrazing interval. Across both systems heterogeneity of utilization was strongly positively correlated with paddock size. Because utilization was not severely patchy in the largest treatment, the difference between systems would likely be greater in commercial-scale paddocks. Thus grazing distribution can be more even under intensive than extensive management, but this depends on how adaptively the system, particularly the aspects of timing and frequency, is managed. 
    • The Page Ranch Story - Its Vegetative History and Management Implications

      Schmutz, Ervin M.; Sourabie, Martin K.; Smith, David A.; School of Renewable Resources, University of Arizona; Bobo; U.S.D.A. Soil Conservation Service (University of Arizona (Tucson, AZ), 1985)
    • Paille Fine

      Williams, R. E. (Society for Range Management, 1951-05-01)
    • Painter and Range Rider

      Frasier, Gary (Society for Range Management, 2009-10-01)
    • Paired 14C and 230Th/U Dating of Surface Corals from the Marquesas and Vanuatu (Sub-Equatorial Pacific) in the 3000 to 15,000 Cal Yr Interval

      Paterne, Martine; Ayliffe, Linda K.; Arnold, Maurice; Cabioch, Guy; Tisnérat-Laborde, Nadine; Edouar, Edouard Bard; Douville, Eric; Bard, Edouard (Department of Geosciences, The University of Arizona, 2004-01-01)
      Paired radiocarbon and 230Th/U dating was performed on 13 surface corals from submerged reefs in the Marquesas and from raised terraces in Vanuatu. The absolute ages of the corals analyzed ranged from 3000 to 15,000 cal yr. Estimates of the difference between the absolute and 14C ages of these corals are in agreement with previous determinations up until 11,500 cal yr. The resulting mean sea surface reservoir age R is determined at 390 +/60 yr for the Marquesas region (9 degrees S), which is slightly higher than the R value at 280 +/50 yr for the Tahiti Islands (18 degrees S). Multiple 14C analyses of 2 corals from the Marquesas present scattered 14C ages at ~12,000 and ~15,100 cal yr. This could be attributed to rapid changes of the 14C content of surface waters around the Marquesas Islands or to a subtle submarine diagenesis.
    • Paired AMS 14C Dates on Planktic Foraminifera from a Gulf of Mexico Sediment Core: An Assessment of Stratigraphic Continuity

      Flower, B. P.; Hastings, D. W.; Randle, N. J. (Department of Geosciences, The University of Arizona, 2011-01-01)
      A series of recent papers has called for multiple radiocarbon dates on planktic foraminifera to assess stratigraphic continuity in deep-sea sediment cores. This recommendation comes from observations of anomalous 14C dates in planktic foraminifera from the same stratigraphic level. Potential reasons include bioturbation, downslope transport, secondary calcification, carbonate dissolution, and differential preservation. In this study, paired 14C dates on dissolution-susceptible Globigerinoides ruber and dissolution-resistant Neogloboquadrina dutertrei are used to evaluate a Gulf of Mexico sediment core. Fourteen of 15 pairs (between 8815 and 12,995 uncorrected 14C yr BP) yield concordant uncorrected 14C ages (mean difference -2 +/- 75 yr), attesting to continuous deposition at high accumulation rates (>35 cm/kyr). For 1 pair, N. dutertrei is nearly 1000 yr younger, which is difficult to explain by any combination of dissolution and bioturbation or downslope transport, given the excellent carbonate preservation and persistent laminations. The concordant ages underscore the utility of paired 14C dates in planktic foraminifera as a means of assessing stratigraphic continuity in deep-sea sediment sequences.
    • Paired Dating of Pith and Outer Edge (Terminus) Samples from Pre-Hispanic Caribbean Wooden Sculptures

      Brock, Fiona; Ostapkowicz, Joanna; Bronk Ramsey, Christopher; Wiedenhoeft, Alex; Cartwright, Caroline (Department of Geosciences, The University of Arizona, 2012-10-15)
      Radiocarbon dating of historical and archaeological wood can be complicated, sometimes involving issues of “inbuilt” age in slow-growing woods, and/or the possibility of reuse or long delays between felling and use of the wood. Terminus dates can be provided by dating the sapwood, or the outermost edge of heartwood, while a date from the pith can give an indication of the first years of growth. A sequence of samples from specific points within the bole can be used to determine the growth rate of the tree. Such a combined dating strategy is particularly useful in cross-referencing dates from a single piece, better placing it in its chronological context. This paper reports paired or multiple dates from 11 wooden sculptures dated as part of the Pre-Hispanic Caribbean Sculptural Arts in Wood project, which studied 66 wooden artifacts attributed to the pre-colonial Taíno, the indigenous peoples of the Caribbean’s Greater Antilles. The calibrated ages of the pieces published here range from ~AD 700–1500, indicating that the Taíno were producing elaborate sculptures much earlier than previously thought. The paired or multiple dates from these carvings confirmed the accuracy of the results, and were also used to construct a growth rate model of what was expected to be a slow-growing species (Guaiacum sp.). This model demonstrates that the boles used to create the sculptures grew on average 1 cm every 6–13 yr.
    • Pairing season habitat selection by Montezuma quail in southeastern Arizona

      Bristow, Kirby D.; Ockenfels, Richard A. (Society for Range Management, 2004-09-01)
      Montezuma quail (Cyrtonyx montezumae Vigors) are closely associated with oak woodlands (Quercus spp.). Livestock grazing and cover availability are considered important factors affecting Montezuma quail distribution and density. While habitat conditions during pairing season (April-June) are thought to be important to Montezuma quail survival and reproduction, information on habitat selection during that time is limited. We investigated habitat selection by Montezuma quail in grazed and ungrazed areas within the Huachuca and Santa Rita mountain foothills in southeastern Arizona. We used pointing dogs to locate quail during the pairing seasons of 1998 and 1999, and measured habitat characteristics at 60 flush sites and 60 associated random plots (within 100 m of flush sites). We recorded information on landform, substrate, vegetation, and cover. Montezuma quail selected (P < 0.10) areas with higher grass canopy cover and more trees than randomly available. Short (≤ 50 cm tall) visual obstruction (cover), usually associated with bunch grass, was greater (P < 0.10) at use sites than at random plots. Land management practices that reduce grass and tree cover may affect Montezuma quail habitat quality and availability in southeastern Arizona. Based on habitat selection patterns of Montezuma quail, we recommend that oak woodland habitats should contain a minimum tree canopy of 26%, and 51-75% grass canopy cover at the 20-cm height to provide optimum cover availability.
    • 'Paiute' Orchardgrass—Forage Species for Semiarid Range and Wildland Sites

      Monsen, Stephen B.; Stevens, Richard (Society for Range Management, 1985-06-01)
    • Palaeosols Within Loess: Dating Palaeoclimatic Events in Kashmir

      Kusumgar, Sheela; Agrawal, D. P.; Juyal, Navin; Sharma, Prabhakar (American Journal of Science, 1986-01-01)
      The 14C dates of Kashmir loess-palaeosols form five clusters. The dates, mineral magnetic, stable isotopic, and pollen data help decipher major climatic oscillations as distinct from the minor ones.
    • Palar... A New Lovegrass for the Southwest

      Joy, R. J.; Slayback, Robert D.; Renney, Clinton W.; Plant Materials Center; Plant Materials Center; Plant Materials Center (College of Agriculture, University of Arizona (Tucson, AZ), 1972)
    • Palatability and Nutrient Value of Cotton Silage

      Hale, William H.; Stith, Lee S; Department of Animal Science; Department of Plant Breeding (College of Agriculture, University of Arizona (Tucson, AZ), 1968)
    • Palatability of Douglasfir Foliage to Mule Deer in Relation to Chemical and Spatial Factors

      Tucker, R. E.; Majak, W.; Parkinson, P. D.; McLean, A. (Society for Range Management, 1976-11-01)
      Relative preference of Douglasfir needles from eight environmental conditions was determined in a feeding trial with penned tame deer of mixed age and sex. Relative preference (percent fresh weight ingested) varied between 0 and 74%, with significant differences between open (16%) and gully (9%) sites, between old (20%) and young (4%) trees, and between tops (16%) and bottoms (8%) of trees. Shading was found to be responsible for some difference in palatability, unshaded being preferred (22%) over shaded needles (4%). Relative preference was found to be correlated with moisture content (r = -0.57). Relative preference was also found to be correlated with chlorogenic acid (r = 0.41), a naturally occurring phenolic ester which was quantified by fluorometric scanning after being observed in a thin layer chromatography (TLC) screening experiment. Crude protein was not significantly correlated with preference.
    • Palatability of Herbage and Animal Preference

      Heady, H. F. (Society for Range Management, 1964-03-01)
    • Palatron: a technique for aligning ultrasound images of the tongue and palate

      Mielke, Jeff; Baker, Adam; Archangeli, Diana; Racy, Sumayya; University of Arizona (University of Arizona Linguistics Circle (Tucson, Arizona), 2005)
      This paper describes a technique for aligning ultrasound images of the tongue to images of the palate, providing both a fixed point of reference and a means to consider the tongue in the context of passive articulators, thereby addressing two major challenges presented by ultrasound as a means of articulatory imaging, without compromising its portability.