437 research outputs found

    Stem-Boring Caterpillars of Switchgrass in the Midwestern United States

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    Lepidopteran stem borers were collected from switchgrass, Panicum virgatum L., tillers showing symptoms of infestation at seven locations in Illinois and Iowa, with additional observations made on larval and adult activity. Blastobasis repartella (Dietz) (Coleophoridae), whose only known host is switchgrass, was common in plots grown for \u3e5 yr, whereas the polyphagous stalk borer, Papaipema nebris (Guenée) (Noctuidae), was abundant in newly established (i.e., first- and second year) switchgrass. Haimbachia albescens Capps (Crambidae) was collected from two locations in Illinois, making switchgrass the first known host for this species. Entry holes made by B. repartella and H. albescens were usually 1-2 cm above the soil surface, precluding discrimination between these species based on external appearance of damage. Although P. nebris often entered stems within 5 cm of the soil surface, they also seemed to move between stems and were the only species entering stems at heights \u3e15 cm. Adults of B. repartella were active on and above the switchgrass canopy by 2130 hours, with peak activity at ≈0230 hours. Activity of B. repartella adults seemed greatly reduced on one night with relatively cool temperatures and low wind speeds. Data from switchgrass and giant ragweed, Ambrosia trifida L., suggest P. nebris larvae move out of switchgrass during July in search of hosts with larger diameter stems, although by then hosts such as corn, Zea mays L., or Miscanthus spp. may have outgrown the potential for serious damage. However, switchgrass could contribute to greater adult populations of P. nebris if thick-stemmed hosts such as giant ragweed are not managed

    Scientific Value of Real-Time Global Positioning System Data

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    The Global Positioning System (GPS) is an example of a Global Navigation Satellite System (GNSS) that provides an essential complement to other geophysical networks because of its high precision, sensitivity to the longest‐period bands, ease of deployment, and ability to measure displacement and atmospheric properties over local to global scales. Recent and ongoing technical advances, combined with decreasing equipment and data acquisition costs, portend rapid increases in accessibility of data from expanding global geodetic networks. Scientists and the public are beginning to have access to these high‐rate, continuous data streams and event‐specific information within seconds to minutes rather than days to months. These data provide the opportunity to observe Earth system processes with greater accuracy and detail, as they occur

    Stem-Boring Caterpillars of Switchgrass in the Midwestern United States

    Get PDF
    Lepidopteran stem borers were collected from switchgrass, Panicum virgatum L., tillers showing symptoms of infestation at seven locations in Illinois and Iowa, with additional observations made on larval and adult activity. Blastobasis repartella (Dietz) (Coleophoridae), whose only known host is switchgrass, was common in plots grown for \u3e5 yr, whereas the polyphagous stalk borer, Papaipema nebris (Guenée) (Noctuidae), was abundant in newly established (i.e., first- and second year) switchgrass. Haimbachia albescens Capps (Crambidae) was collected from two locations in Illinois, making switchgrass the first known host for this species. Entry holes made by B. repartella and H. albescens were usually 1-2 cm above the soil surface, precluding discrimination between these species based on external appearance of damage. Although P. nebris often entered stems within 5 cm of the soil surface, they also seemed to move between stems and were the only species entering stems at heights \u3e15 cm. Adults of B. repartella were active on and above the switchgrass canopy by 2130 hours, with peak activity at ≈0230 hours. Activity of B. repartella adults seemed greatly reduced on one night with relatively cool temperatures and low wind speeds. Data from switchgrass and giant ragweed, Ambrosia trifida L., suggest P. nebris larvae move out of switchgrass during July in search of hosts with larger diameter stems, although by then hosts such as corn, Zea mays L., or Miscanthus spp. may have outgrown the potential for serious damage. However, switchgrass could contribute to greater adult populations of P. nebris if thick-stemmed hosts such as giant ragweed are not managed

    SHCal13 Southern Hemisphere calibration, 0–50,000 years cal BP

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    The Southern Hemisphere SHCal04 radiocarbon calibration curve has been updated with the addition of new data sets extending measurements to 2145 cal BP and including the ANSTO Younger Dryas Huon pine data set. Outside the range of measured data, the curve is based upon the Northern Hemisphere data sets as presented in IntCal13, with an interhemispheric offset averaging 43 ± 23 yr modeled by an autoregressive process to represent the short-term correlations in the offset

    Crowdsourced earthquake early warning

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    Earthquake early warning (EEW) can reduce harm to people and infrastructure from earthquakes and tsunamis, but it has not been implemented in most high earthquake-risk regions because of prohibitive cost. Common consumer devices such as smartphones contain low-cost versions of the sensors used in EEW. Although less accurate than scientific-grade instruments, these sensors are globally ubiquitous. Through controlled tests of consumer devices, simulation of an M_w (moment magnitude) 7 earthquake on California’s Hayward fault, and real data from the M_w 9 Tohoku-oki earthquake, we demonstrate that EEW could be achieved via crowdsourcing

    IntCal09 and Marine09 radiocarbon age calibration curves, 0-50,000yeats cal BP

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    The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0–12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org
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