298 research outputs found
Identifying Forage Quality Eastern Gamagrass [\u3ci\u3eTripsacum dactyloides\u3c/i\u3e (L.) L.] Genotypes from a Wild Regional Collection
Eastern gamagrass is a perennial warm-season grass native to North America and endemic to the eastern United States. The species is highly valuable as both a forage and hay crop. In 2012, 171 wild-type eastern gamagrass accessions were collected from the southeast, mid-Atlantic and Atlantic coast regions. Each accession was relocated to Starkville, MS (33.423585, -88.792394) and established in a long-term nursery. Accessions were analyzed for ploidy level and during 2013-2014 were further evaluated for desirable forage characteristics including: cold tolerance, delayed maturity, rust resistance, and digestibility. Fourteen elite individuals were identified from the original collection and were propagated for further research. Elite genotypes were divided into individual proaxes and transplanted into a RCB design with three replications. Plots measured 3.04 m x 1.21 m with five replicate plants evenly spaced within the plot. Following a one-year establishment period, whole plots were harvested on a 28-day cycle from May to October. Plots were harvested to a 15 cm stubble height with a Wintersteiger Cibus S harvester. Following each harvest, nitrogen fertilizer was applied to all plots at 56 kg N ha-1 using urea ammonium sulfate (32-0-0-12S). Homogenized subsamples were taken to determine percent dry matter, neutral detergent fiber (NDF), acid detergent fiber (ADF), and in-vitro dry matter digestibility (IVDMD). The commercial cultivar ‘Highlander’, was included in the study as a check. Seasonal yields ranged from 1.19 - 2.73 Mg ha-1. Three accessions – originally collected in Alabama and North Carolina – produced significantly greater forage yield than the check (P \u3e 0.0001). Digestibility of the commercial check as well as one accession – collected in Tennessee – were significantly greater than all other accessions (P \u3e 0.0001)
Phenotypic Evaluation of Energycane Varieties for Bioenergy
The need for renewable and carbon-neutral energy is growing as fossil fuel supplies decrease and concerns of climate change increase. C4 grasses are among the most efficient carbon accumulators. Sugarcane (Saccharum officinarum) is a renewable bioenergy crop with low inputs and high yields, but it is limited to tropical and sub-tropical climates. A close relative, Saccharum spontaneum, readily hybridizes with S. officinarum. S. spontaneum lends cold tolerance and higher yields to the hybrid progeny, called energycane. The Sugarcane Breeding Unit (USDA, Houma, Louisiana, USA) selected twenty-six genotypes for testing at Mississippi State University to determine production and cold tolerance at latitude 33.4552° N. Twenty of these genotypes were chosen after the first year for further testing against an energycane check (Ho02-113) and a sugarcane check (L01-299). Seed cane were harvested and planted in the fall of 2019 and 2020 in randomized complete block design with four replications. Plots were 6.1 x 1.8 m, fertilized once at a rate of 168 kg N ha-1. Cane heights and stand counts were collected to monitor genotype growth. At the end of the season, canes were taken for fresh weight, dry weight, °Brix, and sap volume. End of season characteristics of first year growth were: Mean height ranged from 73 to 204 cm; cane number ranged from 9,530 to 68,171 canes ha-1. Plot fresh weights ranged from: 19.9 to 61 Mg ha-1. Mean value of °Brix ranged from 8.9 to 13.7. Mean extractable sap volume ranged from: 2311 to 16,821 L ha-1. Theoretical ethanol yield was calculated for sap and from dry matter. Total theoretical ethanol yield ranged from 939.8 to 3261.2 L ha-1
Cost effectiveness of alternative planned places of birth in woman at low risk of complications: evidence from the Birthplace in England national prospective cohort study
Objectives To estimate the cost effectiveness of alternative planned places of birth
Course-based Science Research Promotes Learning in Diverse Students at Diverse Institutions
Course-based research experiences (CREs) are powerful strategies for spreading learning and improving persistence for all students, both science majors and nonscience majors. Here we address the crucial components of CREs (context, discovery, ownership, iteration, communication, presentation) found across a broad range of such courses at a variety of academic institutions. We also address how the design of a CRE should vary according to the background of student participants; no single CRE format is perfect. We provide a framework for implementing CREs across multiple institutional types and several disciplines throughout the typical four years of undergraduate work, designed to a variety of student backgrounds. Our experiences implementing CREs also provide guidance on overcoming barriers to their implementation
Use of PDV to measure the overdriven products equation of state in PBX 9502 and PBX 9501 and the EOS in shocked foams
Author Institution: Los Alamos National LaboratorySlides presented at the 2014 Photonic Doppler Velocimetry (PDV) Workshop Hosted by National Security Technologies, LLC, and the University of Nevada Las Vegas, June 24-26, 2014, Las Vegas, Nevada
Perinatal and maternal outcomes in planned home and obstetric unit births in women at ‘higher risk’ of complications: secondary analysis of the Birthplace national prospective cohort study
Objective: To explore and compare perinatal and maternal outcomes in women at ‘higher risk’ of complications planning home versus obstetric unit (OU) birth.
Design: Prospective cohort study.
Setting: OUs and planned home births in England.
Population: 8180 ‘higher risk’ women in the Birthplace cohort.
Methods: We used Poisson regression to calculate relative risks adjusted for maternal characteristics. Sensitivity analyses explored possible effects of differences in risk between groups and alternative outcome measures.
Main outcome measures: Composite perinatal outcome measure encompassing ‘intrapartum related mortality and morbidity’ (intrapartum stillbirth, early neonatal death, neonatal encephalopathy, meconium aspiration syndrome, brachial plexus injury, fractured humerus or clavicle) and neonatal admission within 48 hours for more than 48 hours. Two composite maternal outcome measures capturing intrapartum interventions/adverse maternal outcomes and straightforward birth.
Results: The risk of ‘intrapartum related mortality and morbidity’ or neonatal admission for more than 48 hours was lower in planned home births than planned OU births [adjusted relative risks (RR) 0.50, 95% CI 0.31–0.81]. Adjustment for clinical risk factors did not materially affect this finding. The direction of effect was reversed for the more restricted outcome measure ‘intrapartum related mortality and morbidity’ (RR adjusted for parity 1.92, 95% CI 0.97–3.80). Maternal interventions were lower in planned home births.
Conclusions: The babies of ‘higher risk’ women who plan birth in an OU appear more likely to be admitted to neonatal care than those whose mothers plan birth at home, but it is unclear if this reflects a real difference in morbidity. Rates of intrapartum related morbidity and mortality did not differ statistically significantly between settings at the 5% level but a larger study would be required to rule out a clinically important difference between the groups
Reaction rates for Neutron Capture Reactions to C-, N- and O-isotopes to the neutron rich side of stability
The reaction rates of neutron capture reactions on light nuclei are important
for reliably simulating nucleosynthesis in a variety of stellar scenarios.
Neutron capture reaction rates on neutron-rich C-, N-, and O-isotopes are
calculated in the framework of a hybrid compound and direct capture model. The
results are tabulated and compared with the results of previous calculations as
well as with experimental results.Comment: 33 pages (uses revtex) and 9 postscript figures, accepted for
publication in Phys. Rev.
Rubidium, zirconium, and lithium production in intermediate-mass asymptotic giant branch stars
A recent survey of a large sample of Galactic intermediate-mass (>3 Msun)
asymptotic giant branch (AGB) stars shows that they exhibit large
overabundances of rubidium (Rb) up to 100--1000 times solar. These observations
set constraints on our theoretical notion of the slow neutron capture process
(s process) that occurs inside intermediate-mass AGB stars. Lithium (Li)
abundances are also reported for these stars. In intermediate-mass AGB stars,
Li can be produced by proton captures occuring at the base of the convective
envelope. For this reason the observations of Rb, Zr, and Li set complementary
constraints on different processes occurring in the same stars. We present
predictions for the abundances of Rb, Zr, and Li as computed for the first time
simultaneously in intermediate-mass AGB star models and compare them to the
current observational constraints. We find that the Rb abundance increases with
increasing stellar mass, as is inferred from observations but we are unable to
match the highest observed [Rb/Fe] abundances. Inclusion of a partial mixing
zone (PMZ) to activate the 13C(a,n)16O reaction as an additional neutron source
yields significant enhancements in the Rb abundance. However this leads to Zr
abundances that exceed the upper limits of the current observational
constraints. If the third dredge-up (TDU) efficiency remains as high during the
final stages of AGB evolution as during the earlier stages, we can match the
lowest values of the observed Rb abundance range. We predict large variations
in the Li abundance, which are observed. Finally, the predicted Rb production
increases with decreasing metallicity, in qualitative agreement with
observations of Magellanic Cloud AGB stars. However stellar models of Z=0.008
and Z=0.004 intermediate-mass AGB stars do not produce enough Rb to match the
observed abundances.Comment: 11 pages, 7 figures, accepted for publication on Astronomy &
Astrophysic
Recommended from our members
The Birthplace national prospective cohort study: perinatal and maternal outcomes by planned place of birth Birthplace in England research programme.
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Birthplace cost-effectiveness analysis of planned place of birth: individual level analysis Birthplace in England research programme
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