411 research outputs found

    Species Richness Affects Grassland Yield and Yield Stability Across Seasons, Sites and Years

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    The benefits of biodiversity (specifically species richness) are proposed to include both greater yield and greater stability of yield in a variable environment (Sanderson et al., 2004). Experimental evidence showing yield benefits is inconsistent (White et al., 2004). There is relatively little experimental data showing the effects of species richness on yield stability. The objective of this study was to measure the yield from mixtures with up to 12 species, and to measure the variability of yield between 2 sites, between spring and summer, and in 2 successive years

    New Exclusion Limits for the Search of Scalar and Pseudoscalar Axion-Like Particles from "Light Shining Through a Wall"

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    Physics beyond the Standard Model predicts the possible existence of new particles that can be searched at the low energy frontier in the sub-eV range. The OSQAR photon regeneration experiment looks for "Light Shining through a Wall" from the quantum oscillation of optical photons into "Weakly Interacting Sub-eV Particles", such as axion or Axion-Like Particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of 2×14.32 \times 14.3 m. In 2014, this experiment has been run with an outstanding sensitivity, using an 18.5 W continuous wave laser emitting in the green at the single wavelength of 532 nm. No regenerated photons have been detected after the wall, pushing the limits for the existence of axions and ALPs down to an unprecedented level for such a type of laboratory experiment. The di-photon couplings of possible pseudo-scalar and scalar ALPs can be constrained in the nearly massless limit to be less than 3.5⋅10−83.5\cdot 10^{-8} GeV−1^{-1} and 3.2⋅10−83.2\cdot 10^{-8} GeV−1^{-1}, respectively, at 95% Confidence Level.Comment: 6 pages, 6 figure

    Search for weakly interacting sub-eV particles with the OSQAR laser-based experiment: results and perspectives

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    Recent theoretical and experimental studies highlight the possibility of new fundamental particle physics beyond the Standard Model that can be probed by sub-eV energy experiments. The OSQAR photon regeneration experiment looks for "Light Shining through a Wall" (LSW) from the quantum oscillation of optical photons into "Weakly Interacting Sub-eV Particles" (WISPs), like axion or axion-like particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of 2×14.32 \times 14.3 m. No excess of events has been detected over the background. The di-photon couplings of possible new light scalar and pseudo-scalar particles can be constrained in the massless limit to be less than 8.0×10−88.0\times10^{-8} GeV−1^{-1}. These results are very close to the most stringent laboratory constraints obtained for the coupling of ALPs to two photons. Plans for further improving the sensitivity of the OSQAR experiment are presented.Comment: 7 pages, 7 figure

    30 Years of Progress toward Increased Biomass Yield of Switchgrass and Big Bluestem

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    Breeding to improve biomass production of switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) for conversion to bioenergy began in 1992. The purpose of this study was (i) to develop a platform for uniform regional testing of cultivars and experimental populations for these species, and (ii) to estimate the gains made by breeding during 1992 to 2012. A total of 25 switchgrass populations and 16 big bluestem populations were planted in uniform regional trials at 13 locations in 2012 and 2014. The reference region was USDA Hardiness Zones 3 through 6 in the humid temperate United States. Significant progress toward increased biomass yield was made in big bluestem and within upland-ecotype populations, lowland-ecotype populations, and hybrid-derived populations of switchgrass. Four mechanisms of increasing biomass yield were documented: (i) increased biomass yield per se, (ii) later flowering to extend the growing season, (iii) combined later flowering from the lowland ecotype with survivorship of the upland ecotype in hybrid-derived populations, and (iv) increased survivorship of late-flowering lowland populations in hardiness zones that represent an expansion of their natural adaption zone. Switchgrass exhibited all four mechanisms in one or more improved populations, whereas improved populations of big bluestem were likely influenced by two of the four mechanisms. The uniform testing program was successful at documenting increases in biomass yield, identifying the mechanisms for increased yield, and determining adaptation characteristics and limitations of improved populations

    Forages for Horses Revamped

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    The Forages for Horses program began in Ohio in1998 as a collaboration between the Ohio Forages & Grasslands Council and Ohio State University Extension. Over time, additional collaborations with the Natural Resources Conservation Service, Ohio Department of Agriculture and local Soil and Water Conservation Districts expanded the program. At its inception, one to three educators would partner to provide eight hours of in-person lectures followed by a pasture walk to better the management practices of equine enthusiasts. From 2021 through 2022, the curriculum was adapted for a hybrid classroom and included three 90-minute live webinars featuring nine different presentations followed by online social events. The modifications to the curriculum were made to improve access to equine resources and grazing education across Ohio. The Forages for Horses resources were also updated as part of the process. Learning modules posted in Canvas (an online learning management system) provided additional information that expanded upon the original curriculum. In 2022, 41 students from Ohio and surrounding states registered for the online course and webinars. Participants were able to hear directly from educators - more than in past iterations of the program– to expand their depth of knowledge and increase opportunities for participation without the location of the class posing a barrier for attendance. This program will continue to be revised over the coming years to remain relevant and accessible to Ohioans

    HNO Binding in a Heme Protein: Structures, Spectroscopic Properties, and Stabilities

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    HNO can interact with numerous heme proteins, but atomic level structures are largely unknown. In this work, various structural models for the first stable HNO heme protein complex, MbHNO (Mb, myoglobin), were examined by quantum chemical calculations. This investigation led to the discovery of two novel structural models that can excellently reproduce numerous experimental spectroscopic properties. They are also the first atomic level structures that can account for the experimentally observed high stabilities. These two models involve two distal His conformations as reported previously for MbCNR and MbNO. However, a unique dual hydrogen bonding feature of the HNO binding was not reported before in heme protein complexes with other small molecules such as CO, NO, and O2. These results shall facilitate investigations of HNO bindings in other heme proteins

    Fast Photon Detection for Particle Identification with COMPASS RICH-1

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    Particle identification at high rates is an important challenge for many current and future high-energy physics experiments. The upgrade of the COMPASS RICH-1 detector requires a new technique for Cherenkov photon detection at count rates of several 10610^6 per channel in the central detector region, and a read-out system allowing for trigger rates of up to 100 kHz. To cope with these requirements, the photon detectors in the central region have been replaced with the detection system described in this paper. In the peripheral regions, the existing multi-wire proportional chambers with CsI photocathode are now read out via a new system employing APV pre-amplifiers and flash ADC chips. The new detection system consists of multi-anode photomultiplier tubes (MAPMT) and fast read-out electronics based on the MAD4 discriminator and the F1-TDC chip. The RICH-1 is in operation in its upgraded version for the 2006 CERN SPS run. We present the photon detection design, constructive aspects and the first Cherenkov light in the detector.Comment: Proceedings of the Imaging 2006 conference, Stockholm, Sweden, 27-30 June 2006, 5 pages, 6 figures, to appear in NIM A; corrected typo in caption of Fig.
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