164 research outputs found

    Potential Use of Perennial Sunflower to Reduce Blackbird Damage to Sunflower

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    Wildlife Conservation Sunflower Plots (WCSP) have shown potential to reduce blackbird (Icteridae) damage in commercial sunflower. Also known as lure, decoy, or trap crops, WCSP are strategically placed food plots that provide an easily available and proximate food source that entices blackbirds away from valuable commercial crops. By providing an alternative food source, WCSP reduce direct damage to commercial fields, while also lowering indirect costs that producers incur attempting to prevent blackbird damage. However, cost inefficiencies have deterred widespread use of WCSP. Cost-benefit ratios of using WCSP would be greatly improved if a perennial sunflower were used instead of the annual types currently available. Perennial sunflower would reduce seed cost and planting cost, and perhaps lower opportunity costs, if able to thrive on poorer quality soils. In the near-term, scientists are focused on producing a perennial sunflower sufficiently productive to replace annualWCSP plantings. In 2013, scientists from the University of Minnesota, USDA-Agricultural Research Service, and USDAWildlife Services National Wildlife Research Center evaluated a test plot of an open-pollinated variety of perennial sunflower resulting from genetic crossing of a domesticated annual species (Helianthus annuus) and a perennial wild species (H. tuberosus). Here, we report on results from the 2013 field test and discuss the outlook for development of perennial sunflower, which would help lessen damage to commercial sunflower when used in WCSP; provide a pesticide-free food source for beneficial insects, such as honey bees; help stabilize highly erodible lands near wetlands; and provide year-round habitat for wildlife. Lastly, we provide an initial strategy for using perennial sunflower to reduce blackbird damage in commercial sunflower

    Potential Use of Perennial Sunflower to Reduce Blackbird Damage to Sunflower

    Get PDF
    Wildlife Conservation Sunflower Plots (WCSP) have shown potential to reduce blackbird (Icteridae) damage in commercial sunflower. Also known as lure, decoy, or trap crops, WCSP are strategically placed food plots that provide an easily available and proximate food source that entices blackbirds away from valuable commercial crops. By providing an alternative food source, WCSP reduce direct damage to commercial fields, while also lowering indirect costs that producers incur attempting to prevent blackbird damage. However, cost inefficiencies have deterred widespread use of WCSP. Cost-benefit ratios of using WCSP would be greatly improved if a perennial sunflower were used instead of the annual types currently available. Perennial sunflower would reduce seed cost and planting cost, and perhaps lower opportunity costs, if able to thrive on poorer quality soils. In the near-term, scientists are focused on producing a perennial sunflower sufficiently productive to replace annualWCSP plantings. In 2013, scientists from the University of Minnesota, USDA-Agricultural Research Service, and USDAWildlife Services National Wildlife Research Center evaluated a test plot of an open-pollinated variety of perennial sunflower resulting from genetic crossing of a domesticated annual species (Helianthus annuus) and a perennial wild species (H. tuberosus). Here, we report on results from the 2013 field test and discuss the outlook for development of perennial sunflower, which would help lessen damage to commercial sunflower when used in WCSP; provide a pesticide-free food source for beneficial insects, such as honey bees; help stabilize highly erodible lands near wetlands; and provide year-round habitat for wildlife. Lastly, we provide an initial strategy for using perennial sunflower to reduce blackbird damage in commercial sunflower

    Role of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in Modulating Vascular Smooth Muscle Cells by Activating Large-Conductance Potassium Ion Channels

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    International audienceIn this chapter we propose to discuss the role of K+ ion channels in stimulating vasodilatation by altering the membrane potential of vascular smooth muscle cells. We present evidence that the K+ channels are modulated by a direct action of non-steroidal antiinflammatory drugs (NSAIDs) to activate the K+ ion channels

    Detectors and cryostat design for the SuMIRe Prime Focus Spectrograph (PFS)

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    We describe the conceptual design of the camera cryostats, detectors, and detector readout electronics for the SuMIRe Prime Focus Spectrograph (PFS) being developed for the Subaru telescope. The SuMIRe PFS will consist of four identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic positioner at the prime focus. Each spectrograph will have three channels covering wavelength ranges 3800 {\AA} - 6700 {\AA}, 6500 {\AA} - 10000 {\AA}, and 9700 {\AA} - 13000 {\AA}, with the dispersed light being imaged in each channel by a f/1.10 vacuum Schmidt camera. In the blue and red channels a pair of Hamamatsu 2K x 4K edge-buttable CCDs with 15 um pixels are used to form a 4K x 4K array. For the IR channel, the new Teledyne 4K x 4K, 15 um pixel, mercury-cadmium-telluride sensor with substrate removed for short-wavelength response and a 1.7 um cutoff will be used. Identical detector geometry and a nearly identical optical design allow for a common cryostat design with the only notable difference being the need for a cold radiation shield in the IR camera to mitigate thermal background. This paper describes the details of the cryostat design and cooling scheme, relevant thermal considerations and analysis, and discusses the detectors and detector readout electronics

    Hectospec, the MMT's 300 Optical Fiber-Fed Spectrograph

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    The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT in the spring of 2004. A pair of high-speed six-axis robots move the 300 fiber buttons between observing configurations within ~300 s and to an accuracy ~25 microns. The optical fibers run for 26 m between the MMT's focal surface and the bench spectrograph operating at R~1000-2000. Another high dispersion bench spectrograph offering R~5,000, Hectochelle, is also available. The system throughput, including all losses in the telescope optics, fibers, and spectrograph peaks at ~10% at the grating blaze in 1" FWHM seeing. Correcting for aperture losses at the 1.5" diameter fiber entrance aperture, the system throughput peaks at \sim17%. Hectospec has proven to be a workhorse instrument at the MMT. Hectospec and Hectochelle together were scheduled for 1/3 of the available nights since its commissioning. Hectospec has returned \~60,000 reduced spectra for 16 scientific programs during its first year of operation.Comment: 68 pages, 28 figures, to appear in December 2005 PAS

    The structure of the stellar halo of the Andromeda galaxy explored with the NB515 for Subaru/HSC. I.: New Insights on the stellar halo up to 120 kpc

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    We analyse the M31 halo and its substructure within a projected radius of 120 kpc using a combination of Subaru/HSC NB515 and CFHT/MegaCam g- & i-bands. We succeed in separating M31's halo stars from foreground contamination with \sim 90 \% accuracy by using the surface gravity sensitive NB515 filter. Based on the selected M31 halo stars, we discover three new substructures, which associate with the Giant Southern Stream (GSS) based on their photometric metallicity estimates. We also produce the distance and photometric metallicity estimates for the known substructures. While these quantities for the GSS are reproduced in our study, we find that the North-Western stream shows a steeper distance gradient than found in an earlier study, suggesting that it is likely to have formed in an orbit closer to the Milky Way. For two streams in the eastern halo (Stream C and D), we identify distance gradients that had not been resolved. Finally, we investigate the global halo photometric metallicity distribution and surface brightness profile using the NB515-selected halo stars. We find that the surface brightness of the metal-poor and metal-rich halo populations, and the all population can be fitted to a power-law profile with an index of α=1.65±0.02\alpha = -1.65 \pm 0.02, 2.82±0.01-2.82\pm0.01, and 2.44±0.01-2.44\pm0.01, respectively. In contrast to the relative smoothness of the halo profile, its photometric metallicity distribution appears to be spatially non-uniform with nonmonotonic trends with radius, suggesting that the halo population had insufficient time to dynamically homogenize the accreted populations.Comment: 24 pages, 26 figures, 5 tables, submitted to MNRA

    The GALAH survey: velocity fluctuations in the Milky Way using red clump giants

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    If the Galaxy is axisymmetric and in dynamical equilibrium, we expect negligible fluctuations in the residual line-of-sight velocity field. However, non-axisymmetric structures like a bar, spiral arms and merger events can generate velocity fluctuations. Recent results using the APOGEE survey find significant fluctuations in velocity for stars in the midplane (|z|< 0.25 kpc) and out to 5 kpc, which suggests that the dynamical influence of the Milky Way's bar extends out to the Solar neighborhood. Their measured power spectrum has a characteristic amplitude of 11 km/s on a scale of ~ 2.5 kpc. The existence of large streaming motions on these scales has important implications for determining the Sun's motion about the Galactic Centre. Using red clump stars from the GALAH and APOGEE surveys, we map the line-of-sight velocity field around the Sun out to distances of 5 kpc and up to 1.25 kpc from the Galactic Plane. By subtracting a smooth axisymmetric model for the velocity field, we study the residual velocity fluctuations and compare our findings with mock survey generated by Galaxia based on an axisymmetric, steady state model. We find negligible large-scale fluctuations away from the plane. In the mid-plane, we reproduce the earlier APOGEE power spectrum results but with 20\% smaller amplitude (9.5 km/s) after taking a few systematic effects into account (e.g. volume completeness). The amplitude power is further reduced to 6.7 km/s if a flexible axisymmetric model is used. Additionally, our mock simulations show that, in the plane, the distances are underestimated for high mass red clump stars and this can lead to spurious power with amplitude of about 5.5 km/s. Taking this into account, we estimate the amplitude of real fluctuations to be less than 4.2 km/s, about a factor of three less than the previous result from APOGEE

    Social Class

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    Discussion of class structure in fifth-century Athens, historical constitution of theater audiences, and the changes in the comic representation of class antagonism from Aristophanes to Menander

    The Ghost of Sagittarius and Lumps in the Halo of the Milky Way

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    We identify new structures in the halo of the Milky Way Galaxy from positions, colors and magnitudes of five million stars detected in the Sloan Digital Sky Survey. Most of these stars are within 1.26 degrees of the celestial equator. We present color-magnitude diagrams (CMDs) for stars in two previously discovered, tidally disrupted structures. The CMDs and turnoff colors are consistent with those of the Sagittarius dwarf galaxy, as had been predicted. In one direction, we are even able to detect a clump of red stars, similar to that of the Sagittarius dwarf, from stars spread across 110 square degrees of sky. Focusing on stars with the colors of F turnoff objects, we identify at least five additional overdensities of stars. Four of these may be pieces of the same halo structure, which would cover a region of the sky at least 40 degrees in diameter, at a distance of 11 kpc from the Sun (18 kpc from the center of the Galaxy). The turnoff is significantly bluer than that of thick disk stars, and closer to the Galactic plane than a power-law spheroid. We suggest two models to explain this new structure. One possibility is that this new structure could be a new dwarf satellite of the Milky Way, hidden in the Galactic plane, and in the process of being tidally disrupted. The other possibility is that it could be part of a disk-like distribution of stars which is metal-poor, with a scale height of approximately 2 kpc and a scale length of approximately 10 kpc. The fifth overdensity, which is 20 kpc away, is some distance from the Sagittarius dwarf streamer orbit and is not associated with any known structure in the Galactic plane. It is likely that there are many smaller streams of stars in the Galactic halo.Comment: ApJ, in press; 26 figures including several in colo
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