4,034 research outputs found
Hubble Space Telescope observations of Mars
Hubble Space Telescope (HST) afforded the possibility of resolving features as small as 100 km on the Martian surface even when it is at the far point of its orbit. Therefore it is ideally suited for monitoring seasonal changes on the red planet. The objectives research include: the study of Martian dust storms; use of images obtained through different filters to study the spectral reflectance of regions on the Martian surface; use of ultraviolet images and spectra to measure the amount of ozone in the planet's atmosphere as a function of location of the planet; use of images to study changes in the albedo of the Mars surface; and use of Planetary Camera images to study Martian clouds and to measure the opacity of the atmosphere
Resistance of Kansas Sclerotinia homoeocarpa isolates to thiophanate-methyl and determination of associated β-tubulin mutation
Citation: Ostrander, J., Todd, R., & Kennelly, M. (2014). Resistance of Kansas Sclerotinia homoeocarpa Isolates
to Thiophanate-Methyl and Determination of Associated β-Tubulin Mutation. Plant Health Progress, 15(2), 23-27.
https://doi.org/10.1094/PHP-RS-13-0120.Eighty-two isolates of Sclerotinia homoeocarpa from 12 sites in Kansas were evaluated for in vitro sensitivity to the methyl benzimidazole carbamate (MBC) fungicide thiophanate-methyl at the discriminatory dose of 10 μg/ml. Seventeen isolates were sensitive to thiophanate-methyl and the remaining isolates were resistant. Of the 65 isolates from golf course putting greens, two isolates were sensitive and the remaining 63 isolates were resistant. Six resistant and five sensitive isolates were also evaluated in greenhouse assays on fungicide-treated plants. The isolates that were sensitive to thiophanate-methyl in vitro did not cause any disease on thiophanate-methyl-treated plants, and those that were resistant in vitro caused blighting on treated plants equivalent to the nontreated controls. The entire β-tubulin gene was sequenced for four resistant and four sensitive isolates. The resistant isolates all harbored a substitution of alanine for glutamic acid at codon 198 (E198A). These results provide a starting point for further surveys and monitoring of fungicide sensitivity
Modeling raccoon (Procyon lotor) habitat connectivity to identify potential corridors for rabies spread
The United States Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS), Wildlife Services National Rabies Management Program has conducted cooperative oral rabies vaccination (ORV) programs since 1997. Understanding the eco-epidemiology of raccoon (Procyon lotor) variant rabies (raccoon rabies) is critical to successful management. Pine (Pinus spp.)-dominated landscapes generally support low relative raccoon densities that may inhibit rabies spread. However, confounding landscape features, such as wetlands and human development, represent potentially elevated risk corridors for rabies spread, possibly imperiling enhanced rabies surveillance and ORV planning. Raccoon habitat suitability in pine-dominated landscapes in Massachusetts, Florida, and Alabama was modeled by the maximum entropy (Maxent) procedure using raccoon presence, and landscape and environmental data. Replicated (n = 100/state) bootstrapped Maxent models based on raccoon sampling locations from 2012–2014 indicated that soil type was the most influential variable in Alabama (permutation importance PI = 38.3), which, based on its relation to landcover type and resource distribution and abundance, was unsurprising. Precipitation (PI = 46.9) and temperature (PI = 52.1) were the most important variables in Massachusetts and Florida, but these possibly spurious results require further investigation. The Alabama Maxent probability surface map was ingested into Circuitscape for conductance visualizations of potential areas of habitat connectivity. Incorporating these and future results into raccoon rabies containment and elimination strategies could result in significant cost-savings for rabies management here and elsewhere
Characterization of the Mutagenic Spectrum of 4-Nitroquinoline 1-Oxide (4-NQO) in Aspergillus nidulans by Whole Genome Sequencing
4-Nitroquinoline 1-oxide (4-NQO) is a highly carcinogenic chemical that induces mutations in bacteria, fungi, and animals through the formation of bulky purine adducts. 4-NQO has been used as a mutagen for genetic screens and in both the study of DNA damage and DNA repair. In the model eukaryote Aspergillus nidulans, 4-NQO−based genetic screens have been used to study diverse processes, including gene regulation, mitosis, metabolism, organelle transport, and septation. Early work during the 1970s using bacterial and yeast mutation tester strains concluded that 4-NQO was a guanine-specific mutagen. However, these strains were limited in their ability to determine full mutagenic potential, as they could not identify mutations at multiple sites, unlinked suppressor mutations, or G:C to C:G transversions. We have now used a whole genome resequencing approach with mutant strains generated from two independent genetic screens to determine the full mutagenic spectrum of 4-NQO in A. nidulans. Analysis of 3994 mutations from 38 mutant strains reveals that 4-NQO induces substitutions in both guanine and adenine residues, although with a 19-fold preference for guanine. We found no association between mutation load and mutagen dose and observed no sequence bias in the residues flanking the mutated purine base. The mutations were distributed randomly throughout most of the genome. Our data provide new evidence that 4-NQO can potentially target all base pairs. Furthermore, we predict that current practices for 4-NQO−induced mutagenesis are sufficient to reach gene saturation for genetic screens with feasible identification of causative mutations via whole genome resequencing
Work-Family Conflict, Family-Supportive Supervisor Behaviors (FSSB), and Sleep Outcomes
Although critical to health and well-being, relatively little research has been conducted in the organizational literature on linkages between the work-family interface and sleep. Drawing on Conservation of Resources theory, we use a sample of 623 information technology workers to examine the relationships between work-family conflict, family-supportive supervisor behaviors (FSSB), and sleep quality and quantity. Validated wrist actigraphy methods were used to collect objective sleep quality and quantity data over a one week period of time, and survey methods were used to collect information on self-reported work-family conflict, FSSB, and sleep quality and quantity. Results demonstrated that the combination of predictors (i.e., work-to-family conflict, family-to-work conflict, FSSB) was significantly related to both objective and self-report measures of sleep quantity and quality. Future research should further examine the work-family interface to sleep link and make use of interventions targeting the work-family interface as a means for improving sleep health
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Needs Assessment for Future US Pear Rootstock Research Directions Based on the Current State of Pear Production and Rootstock Research
The area devoted to pear production in the United States (U.S.) is declining due to lack of precocity and high
cost of production. The U.S. pear industry currently lacks "modern" orchard systems characterized by compact
trees that produce early, high yields of large, high quality fruit. Tall, shaded canopies are not economically sustainable
and are at a competitive disadvantage for attracting and sustaining a labor supply. There is broad and deep
consensus in the pear industry that developing size-controlling rootstocks is imperative to remain competitive nationally
and globally. Currently employed rootstocks in the U.S. are Pyrus communis seedlings and clones, none
of which achieve more than about a one-third size reduction, and P betulifolia seedlings. Quince (C. oblonga),
used with interstems in Europe and South America, is utilized commercially (without interstems) in the U.S. only
for 'Cornice' in southern Oregon and northern California. This is due primarily to a lack of cold hardiness needed
in more northern production areas, a lack of graft-compatibility with the other major scion cultivars, fire blight
and iron chlorosis susceptibility, and relative lack of productivity versus other rootstocks, especially in California.
Current evaluative trials rely on older U.S. and imported selections, and include the NC-140 Multistate
Rootstock Research Project and several individual programs in California, New York, Oregon and Washington.
A fundamental deficiency is the lack of a mature pear rootstock breeding program, despite access to the USDAARS
National Clonal Germplasm Repository (NCGR), which holds a major worldwide collection of Pyrus and
related genera. International breeding programs focus on increasing yield efficiency, but also graft compatibility,
fruit quality and size, high soil pH tolerance, winter hardiness, warm climate/low chilling adaptation, drought and
salt tolerance, and resistance to fire blight, pear decline, and pear scab. An intensive planning and implementation
effort is needed to develop the necessary contacts, collaborations, explorations, and importation logistics to
acquire the most promising clonal selections for propagation and testing. Basic research needs include effects of
dwarfing rootstock on tree architecture and fruiting, the underlying mechanisms of dwarfing functional in pear,
the inheritance of key traits, and selection criteria for breeding. Propagation and orchard systems have also been
identified as major research needs
The UV Properties of the Narrow Line Quasar I Zwicky 1
I Zw 1 is the prototype narrow line quasar. We report here the results of our
study of the UV emission of I Zw 1 using a high S/N (50-120) spectrum obtained
with the HST FOS. The following main new results are obtained: 1. The Mg II and
Al III doublets are partially/fully resolved. The measured doublet ratios
verify theoretical predictions that the lines are thermalized in the BLR. 2. A
weak associated UV absorption system is detected in N~V, and possibly also in C
IV and Lya, suggesting an outflow with a velocity of 1870 km/s and velocity
dispersion <300 km/s. 3. Lines from ions of increasing ionization level show
increasing excess blue wing flux, and an increasing line peak velocity shift,
reaching a maximum blueshift of about 2000 km/s for He II 1640. This may
indicate an out-flowing component in the BLR, where the ionization level
increases with velocity, and which is visible only in the approaching
direction. The highest velocity part of this outflow may produce the associated
UV absorption system. 4. The small C III] 1909 EW, and the small C III]
1909/Lya and C III] 1909/Si III] 1892 flux ratios indicate a typical BLR
density of 10^11, i.e. about an order of magnitude larger than implied by C
III] 1909 in most quasars. A BLR component of a higher density is implied by
the EW and doublet ratio of the Al III 1857 doublet. 5. Prominent Fe II UV 191
emission is seen, together with weaker line emission at 1294 and 1871 A. These
three features have been proposed as evidence for significant Lya pumping of
the 8-10 eV levels of Fe II. 6. Significant Fe III emission is present. The Fe
III UV 34 and UV 48 multiplets are clearly resolved, and Fe III UV 1, UV 47, UV
50, and UV 68 may also be present. (Shortened version)Comment: 28 pages, 1 table and 7 figures included. Uses aas2pp4.sty. Scheduled
for the Astrophysical Journal November 10, 1997 issue, Vol. 48
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