282 research outputs found
Brown Patch Occurrence in a Zoysiagrass-Tall Fescue Polystand Compared to a Tall Fescue Monostand
Research has demonstrated that polystands of zoysiagrass and tall fescue can be established successfully, with the potential to provide a high quality turfgrass stand with reduced inputs. Our objective was to determine whether mixing zoysiagrass with tall fescue will reduce brown patch severity while maintaining overall acceptÂable quality. Studies were established at the Rocky Ford Turfgrass Research Center in Manhattan, KS. In the split-plot design, natural infection by Rhizoctonia solani or a fungicide-treated control was the whole plot treatment factor and species (tall fescue monostand and the zoysiagrass/tall fescue mixture) were subplots. During July and August 2016 and 2017, when hot, humid weather triggered brown patch, excessive irrigation was applied to promote brown patch. Disease severity was meaÂsured by visual ratings and digital image analysis; number of leaves in each plot that were infected was recorded using a grid. The mixed stand then showed less plot area affected by brown patch disease compared to the monostand of tall fescue
Evaluating Zoysiagrass-Tall Fescue Mixtures in Kansas
Water conservation is increasingly important when selecting turfgrasses. Zoysiagrass (Zoysia japonica), a C4 grass, is more drought resistant than C3 grasses. However, there is some resistance to the use of zoysiagrass in lawns and golf courses due to its extended dormant period when turf is brown. The objective of this study was to evaluate mowing height, and tall fescue seeding rate and time for establishment of a mixed stand with seeded zoysiagrass. Seeding zoysiagrass and tall fescue together in June generally resulted in a less uniform mixture than seeding zoysiagrass in June and then seeding tall fescue in September. Tall fescue seeded in September at 8 lb of pure live seed (PLS)/1,000 ft2 resulted the most uniform mixture of the two species
Evaluating Large Patch-Tolerant and Cold Hardy Zoysiagrass Germplasm in the Transition Zone
A Zoysia japonica genotype, TAES 5645, that exhibited partial resistance to large patch in preliminary studies conducted by our collaborators at Texas A&M University, was used as a breeding parent at Texas A&M and crossed with 22 cold hardy zoysiagrasses, resulting in 2,858 progeny. These progeny were evaluated for cold hardiness and agronomic traits (establishment rate, overall quality, spring green up, leaf texture, and genetic color) in Manhattan, KS; West Lafayette, IN; and Dallas, TX; from 2012 to 2014. This report focuses on the Manhattan, KS, results. From this work, 60 progeny were identified for further evaluation in larger plots. In fall 2016, ‘Meyer’ (42% of plot area affected) had more large patch than all zoysiagrass progeny (0 to 23%). In spring 2017, Meyer had 33% large patch, higher than most progeny. Among this group of experimental zoysiagrasses, there appear to be promising progeny that have good winter hardiness, resistance to large patch, and improved turf quality characteristics. Data collection is ongoing
KINETIC AND SEX-BASED ANALYSIS OF THE TRADITIONAL AND HORIZONTAL HANG CLEAN
The horizontal hang clean (H-HC) is a novel variation of the traditional hang clean (T-HC). This study evaluated the H-HC and T-HC and compared the horizontal and vertical ground reaction forces and the ratio of those forces (H:V), to the horizontal and vertical ground reaction forces and H:V of the countermovement jump (CMJ) and standing sprint start (SSS). Ten men and ten women NCAA Division III athletes performed the T-HC, H-HC, CMJ, and SSS on a force platform. Results revealed that the H-HC produced a significantly (p ≤ 0.001) greater H:V than the T-HC. There was no interaction between any of these variables and sex (p \u3e 0.05). The H-HC should be included in training programs of men and women to increase the likelihood of transfer of training to activities such as sprinting
Possible Role of Caffeine in Nicotine Use Onset Among Early Adolescents: Evidence from the Young Mountaineer Health Study Cohort
Background
Preventing nicotine use onset among children and youth is an important public health goal. One possible contributor that has received little empirical investigation is caffeine use. The goal of this study was to examine the possible contribution of caffeine to nicotine onset during early adolescence.
Methods
We used data from the Young Mountaineer Health Study Cohort. Survey data were collected from 1,349 (response rate: 80.7%) 6th grade students (mean age at baseline 11.5 years) in 20 middle schools in West Virginia during the fall of 2020 and spring of 2021. We limited our analyses to students reporting never having used any form of nicotine at baseline. Logistic regression was employed in analyses.
Results
Approximately 8% of participants reported having used nicotine at least once between baseline and the follow-up, and 4.7% reported solely using electronic nicotine delivery systems (ENDS) and no other forms of nicotine. In multivariable analyses, we controlled for many environmental, social, and behavioral variables known to influence nicotine use such as alcohol use, peer substance use, and perceived access to nicotine. We formulated our main independent variable, caffeine consumption, as continuous deciles. Any nicotine use, as well as ENDS use only at follow-up, were modeled as dependent variables. Caffeine was significantly associated with nicotine use in both models with ORs of 1.15 (1.04–1.27) and 1.13 (1.00–1.28).
Conclusions
Caffeine consumption among 6th grade non-nicotine users was associated with nicotine use at approximately 6-months follow-up
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The Extended Blue Continuum and Line Emission around the Central Radio Galaxy in Abell 2597
We present results from detailed imaging of the centrally dominant radio
elliptical galaxy in the cooling flow cluster Abell 2597, using data obtained
with the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space
Telescope (HST). This object is one of the archetypal "blue-lobed" cooling flow
radio elliptical galaxies, also displaying a luminous emission-line nebula, a
compact radio source, and a significant dust lane and evidence of molecular gas
in its center. We show that the radio source is surrounded by a complex network
of emission-line filaments, some of which display a close spatial association
with the outer boundary of the radio lobes. We present a detailed analysis of
the physical properties of ionized and neutral gas associated with the radio
lobes, and show that their properties are strongly suggestive of direct
interactions between the radio plasma and ambient gas. We resolve the blue
continuum emission into a series of knots and clumps, and present evidence that
these are most likely due to regions of recent star formation. We investigate
several possible triggering mechanisms for the star formation, including direct
interactions with the radio source, filaments condensing from the cooling flow,
or the result of an interaction with a gas-rich galaxy, which may also have
been responsible for fueling the active nucleus. We propose that the properties
of the source are plausibly explained in terms of accretion of gas by the cD
during an interaction with a gas-rich galaxy, which combined with the fact that
this object is located at the center of a dense, high-pressure ICM can account
for the high rates of star formation and the strong confinement of the radio
source.Comment: Astrophysical Journal, in press, 34 pages, includes 6 PostScript
figures. Latex format, uses aaspp4.sty and epsf.sty file
The Morphologies and Alignments of Gas, Mass, and the Central Galaxies of CLASH Clusters of Galaxies
Morphology is often used to infer the state of relaxation of galaxy clusters. The regularity, symmetry, and degree to which a cluster is centrally concentrated inform quantitative measures of cluster morphology. The Cluster Lensing and Supernova survey with Hubble Space Telescope (CLASH) used weak and strong lensing to measure the distribution of matter within a sample of 25 clusters, 20 of which were deemed to be "relaxed" based on their X-ray morphology and alignment of the X-ray emission with the Brightest Cluster Galaxy. Toward a quantitative characterization of this important sample of clusters, we present uniformly estimated X-ray morphological statistics for all 25 CLASH clusters. We compare X-ray morphologies of CLASH clusters with those identically measured for a large sample of simulated clusters from the MUSIC-2 simulations, selected by mass. We confirm a threshold in X-ray surface brightness concentration of C ≳ 0.4 for cool-core clusters, where C is the ratio of X-ray emission inside 100 h_(70)^(−1) kpc compared to inside 500 h_(70)^(-1)kpc. We report and compare morphologies of these clusters inferred from Sunyaev–Zeldovich Effect (SZE) maps of the hot gas and in from projected mass maps based on strong and weak lensing. We find a strong agreement in alignments of the orientation of major axes for the lensing, X-ray, and SZE maps of nearly all of the CLASH clusters at radii of 500 kpc (approximately 1/2 R_(500) for these clusters). We also find a striking alignment of clusters shapes at the 500 kpc scale, as measured with X-ray, SZE, and lensing, with that of the near-infrared stellar light at 10 kpc scales for the 20 "relaxed" clusters. This strong alignment indicates a powerful coupling between the cluster- and galaxy-scale galaxy formation processes
Population Genomic Analysis Reveals Differential Evolutionary Histories and Patterns of Diversity across Subgenomes and Subpopulations of Brassica napus L.
The allotetraploid species Brassica napus L. is a global crop of major economic importance, providing canola oil (seed) and vegetables for human consumption and fodder and meal for livestock feed. Characterizing the genetic diversity present in the extant germplasm pool of B. napus is fundamental to better conserve, manage and utilize the genetic resources of this species. We used sequence-based genotyping to identify and genotype 30,881 SNPs in a diversity panel of 782 B. napus accessions, representing samples of winter and spring growth habits originating from 33 countries across Europe, Asia and America. We detected strong population structure broadly concordant with growth habit and geography, and identified three major genetic groups: spring (SP), winter Europe (WE), and winter Asia (WA). Subpopulation-specific polymorphism patterns suggest enriched genetic diversity within the WA group and a smaller effective breeding population for the SP group compared to WE. Interestingly, the two subgenomes of B. napus appear to have different geographic origins, with phylogenetic analysis placing WE and WA as basal clades for the other subpopulations in the C and A subgenomes, respectively. Finally, we identified 16 genomic regions where the patterns of diversity differed markedly from the genome-wide average, several of which are suggestive of genomic inversions. The results obtained in this study constitute a valuable resource for worldwide breeding efforts and the genetic dissection and prediction of complex B. napus traits
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