Growth Responses of Zoysia spp. under Tree Shade in the Midwestern United States

‘Meyer’ zoysiagrass (Zoysia japonica Steudel) is commonly planted on home lawns and golf courses in the transition zone; however, poor shade tolerance limits its widespread use. This study was conducted to determine changes and differences in growth among selected Zoysia cultivars and progeny under a natural shade environment over a 3-year period in the transition zone. The study was initiated in June 2010 at the Rocky Ford Turfgrass Research Center in Manhattan, KS. Soil type was a Chase silt loam (fine, montmorillonitic, mesic, Aquic, Argiudoll). Zoysia genotypes were sodded in 0.37-m2 plots and arranged in a randomized complete block with five replications under silver maple (Acer saccharinum L.) shade that resulted in a 91% reduction in photosynthetically active radiation (PAR). Genotypes included ‘Zorro’ [Z. matrella (L.) Merrill], ‘Emerald’ [Z. japonica × Z. pacifica (Goudswaard) Hotta & Kuroki], ‘Meyer’, Chinese Common (Z. japonica), and experimental progeny Exp1 (Z. matrella × Z. japonica), and Exp2 and Exp3 [(Z. japonica × Z. pacifica) × Z. japonica]. ‘Zorro’ and ‘Emerald’ experienced winter injury, which negatively affected their performance. Tiller numbers decreased 47% in ‘Meyer’ from June 2010 to June 2012, but declines in [(Z. japonica × Z. pacifica) × Z. japonica] progeny were only 1% for Exp2 and 27% for Exp3, and both Exp2 and Exp3 maintained high percent green cover throughout the study. In general, by the third year of evaluation, progeny of [(Z. japonica × Z. pacifica) × Z. japonica] had higher quality ratings and higher tiller numbers than ‘Meyer’ and may provide more shade-tolerant cultivar choices for transition zone turf managers

Urban Lawn Microclimates Affect Reference Evapotranspiration

Grass reference evapotranspiration (ETo) obtained from weather stations in open locations is often used to estimate irrigation requirements of turfgrass in local or regional urban lawns. However, the environments of urban lawns are often altered by surrounding buildings, trees, etc., to form various microclimates that may alter evapotranspiration (ET). Our research, which placed weather stations in urban lawns and nearby open swards of turfgrass, revealed ETo was 41% lower in residential lawn microclimates than in nearby open turfgrass swards. Less ET within urban lawns than in nearby open swards suggests using standard historical weather data to estimate irrigation amounts in urban lawns (based on ETo) is problematic, because historical weather data is typically obtained from open areas such as local airports (Ley et al., 1996; Romero and Dukes, 2013). Consequently, the use of weather stations located onsite, or at least in an urban lawn within the same region, may improve estimates of lawn irrigation requirements

Direct Drive Hall Thruster System Development

The sta:us of development of a Direct Drive Ha!! Thruster System is presented. 13 the first part. a s:udy of the impacts to spacecraft systems and mass benefits of a direct-drive architecture is reviewed. The study initially examines four cases of SPT-100 and BPT-4000 Hall thrusters used for north-south station keeping on an EXPRESS-like geosynchronous spacecraft and for primary propulsion for a Deep Space- 1 based science spacecraft. The study is also extended the impact of direct drive on orbit raising for higher power geosynchronous spacecraft and on other deep space missions as a function of power and delta velocity. The major system considerations for accommodating a direct drive Hall thruster are discussed, including array regulation, system grounding, distribution of power to the spacecraft bus, and interactions between current-voltage characteristics for the arrays and thrusters. The mass benefit analysis shows that, for the initial cases, up to 42 kg of dry mass savings is attributable directly to changes in the propulsion hardware. When projected mass impacts of operating the arrays and the electric power system at 300V are included, up to 63 kg is saved for the four initial cases. Adoption of high voltage lithium ion battery technology is projected to further improve these savings. Orbit raising of higher powered geosynchronous spacecraft, is the mission for which direct drive provides the most benefit, allowing higher efficiency electric orbit raising to be accomplished in a limited period of time, as well as nearly eliminating significant power processing heat rejection mass. The total increase in useful payload to orbit ranges up to 278 kg for a 25 kW spacecraft, launched from an Atlas IIA. For deep space missions, direct drive is found to be most applicable to higher power missions with delta velocities up to several km/s , typical of several Discovery-class missions. In the second part, the status of development of direct drive propulsion power electronics is presented. The core of this hardware is the heater-keeper-magnet supply being qualified for the BPT-4000 by Aerojet. A breadboard propulsion power unit is in fabrication and is scheduled for delivery late in 2003

Pahs, Ionized Gas, and Molecular Hydrogen in Brightest Cluster Galaxies of Cool Core Clusters of Galaxies

We present measurements of 5-25 {\mu}m emission features of brightest cluster galaxies (BCGs) with strong optical emission lines in a sample of 9 cool-core clusters of galaxies observed with the Infrared Spectrograph on board the Spitzer Space Telescope. These systems provide a view of dusty molecular gas and star formation, surrounded by dense, X-ray emitting intracluster gas. Past work has shown that BCGs in cool-core clusters may host powerful radio sources, luminous optical emission line systems, and excess UV, while BCGs in other clusters never show this activity. In this sample, we detect polycyclic aromatic hydrocarbons (PAHs), extremely luminous, rotationally-excited molecular hydrogen line emission, forbidden line emission from ionized gas ([Ne II] and [Ne III]), and infrared continuum emission from warm dust and cool stars. We show here that these BCGs exhibit more luminous forbidden neon and H2 rotational line emission than star-forming galaxies with similar total infrared luminosities, as well as somewhat higher ratios of 70 {\mu}m / 24 {\mu}m luminosities. Our analysis suggests that while star formation processes dominate the heating of the dust and PAHs, a heating process consistent with suprathermal electron heating from the hot gas, distinct from star formation, is heating the molecular gas and contributing to the heating of the ionized gas in the galaxies. The survival of PAHs and dust suggests that dusty gas is somehow shielded from significant interaction with the X-ray gas.Comment: 27 preprint pages, 18 figures, accepted by Astrophysical Journa

Detection of Powerful Mid-IR H_2 Emission in the Bridge between the Taffy Galaxies

We report the detection of strong, resolved emission from warm H_2 in the Taffy galaxies and bridge. Relative to the continuum and faint polyclic aromatic hydrocarbon (PAH) emission, the H_2 emission is the strongest in the connecting bridge, approaching L(H_2)/L(PAH 8 μm) = 0.1 between the two galaxies, where the purely rotational lines of H_2 dominate the mid-infrared spectrum in a way very reminiscent of the group-wide shock in the interacting group Stephan's Quintet (SQ). The surface brightness in the 0-0 S(0) and S(1) H_2 lines in the bridge is more than twice that observed at the center of the SQ shock. We observe a warm H2 mass of 4.2 × 10^8 M_☉ in the bridge, but taking into account the unobserved bridge area, the total warm mass is likely to be twice this value. We use excitation diagrams to characterize the warm molecular gas, finding an average surface mass of ~5 × 10^6 M_☉ kpc^(–2) and typical excitation temperatures of 150-175 K. H_2 emission is also seen in the galaxy disks, although there the emission is more consistent with normal star-forming galaxies. We investigate several possible heating mechanisms for the bridge gas but favor the conversion of kinetic energy from the head-on collision via turbulence and shocks as the main heating source. Since the cooling time for the warm H_2 is short (~5000 yr), shocks must be permeating the molecular gas in the bridge region in order to continue heating the H_2

Geographic variation in the community structure of lice on western scrub-jays

ABSTRACT: Parasites are incredibly diverse. An important factor in the evolution of this diversity is the fact that many parasite species are restricted to 1, or just a few, host species. In addition, some parasites exhibit geographic specificity that is nested within their specificity to a particular species of host. The environmental factors that restrict parasites to particular regions within the host's range are poorly understood, and it is often difficult to know whether such patterns of geographic specificity are real, or merely artifacts of uneven host sampling. For over a decade, we sampled communities of ectoparasitic lice (Phthiraptera) from western scrub-jays (Aphelocoma californica) throughout their range in the United States, and found 3 common species of lice. Philopterus crassipes was found throughout the host range, whereas the other 2 species of lice had more restricted distributions. Brueelia deficiens was found only on the woodhouseii host subspecies group, and Myrsidea sp. was found largely on the californica host subspecies group. We suggest that differential tolerance to arid conditions and interspecific competition has led to the restricted geographic distributions of these 2 species of lice

Blood profile holds clues to role of infection in a premonitory state for idiopathic parkinsonism and of gastrointestinal infection in established disease

The two-stage neuroinflammatory process, containment and progression, proposed to underlie neurodegeneration may predicate on systemic inflammation arising from the gastrointestinal tract. Helicobacter infection has been described as one switch in the pathogenic-circuitry of idiopathic parkinsonism (IP): eradication modifies disease progression and marked deterioration accompanies eradication-failure. Moreover, serum Helicobacter-antibody-profile predicts presence, severity and progression of IP. Slow gastrointestinal-transit precedes IP-diagnosis and becomes increasingly-apparent after, predisposing to small-intestinal bacterial-overgrowth (SIBO). Although IP is well-described as a systemic illness with a long prodrome, there has been no comprehensive overview of the blood profile. Here, it is examined in relation to Helicobacter status and lactulose-hydrogen-breath-testing for SIBO

Quasar Accretion Disk Sizes from Continuum Reverberation Mapping in the DES Standard-star Fields

Measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. We present the accretion disk sizes of 22 quasars from continuum reverberation mapping with data from the Dark Energy Survey (DES) standard-star fields and the supernova C fields. We construct continuum light curves with the griz photometry that span five seasons of DES observations. These data sample the time variability of the quasars with a cadence as short as 1 day, which corresponds to a rest-frame cadence that is a factor of a few higher than most previous work. We derive time lags between bands with both JAVELIN and the interpolated cross-correlation function method and fit for accretion disk sizes using the JAVELIN thin-disk model. These new measurements include disks around black holes with masses as small as ~107 M ⊙, which have equivalent sizes at 2500 A as small as ~0.1 lt-day in the rest frame. We find that most objects have accretion disk sizes consistent with the prediction of the standard thin-disk model when we take disk variability into account. We have also simulated the expected yield of accretion disk measurements under various observational scenarios for the Large Synoptic Survey Telescope Deep Drilling Fields. We find that the number of disk measurements would increase significantly if the default cadence is changed from 3 days to 2 days or 1 day

NACHOS, a CubeSat-Based High-Resolution UV-Visible Hyperspectral Imager for Remote Sensing of Trace Gases: System Overview, Science Objectives, and Preliminary Results

The Nano-satellite Atmospheric Chemistry Hyperspectral Observation System (NACHOS) is a high-throughput (f/2.9), high spectral resolution (1.3 nm optical, 0.57 nm sampling) hyperspectral imager covering the 300-500 nm spectral region with 350 spectral bands. The combined 1.5U instrument payload and 1.5U spacecraft bus comprise a 3U CubeSat. Spectroscopically similar to NASA’s Ozone Monitoring Instrument (OMI), which provides wide-field coverage at ~20 km spatial resolution, NACHOS offers complementary targeted measurements at far higher spatial resolution of ~0.4 km/pixel from 500 km altitude over its 15 ̊ across-track field of view. NACHOS incorporates highly streamlined onboard gas-retrieval algorithms, alleviating the need to routinely downlink massive hyperspectral data cubes. This paper discusses the instrument design, requirements leading to it, preliminary results, and science goals, including monitoring NO2 as a proxy for anthropogenic greenhouse gases, low-level degassing of SO2 and halogen oxides at pre-eruptive volcanoes, and formaldehyde from wildfires. Aiming for an eventual many-satellite constellation providing both high spatial resolution and frequent target revisits, the current NACHOS project is launching two CubeSats, the first already launched to the International Space Station aboard the NG-17 Cygnus vehicle on February 19, 2022 and awaiting deployment to its final orbit in June, and the second launching June 29, 2022