791 research outputs found
Effect of Biofertilizer in Organic and Conventional Systems on Growth, Yield and Baking Quality of Hard Red Winter Wheat
A two-year study (harvest years 2019 and 2020) was conducted to investigate the effect of a commercially available biofertilizer, in combination with variable nitrogen (N) rate, on bread baking quality and agronomic traits in hard winter wheat grown in conventional (CONV) and organic (ORG) farming systems in Kentucky, USA. The hard red winter wheat cultivar ‘Vision 45’ was used with three N rates (44, 89.6 and 134.5 kg/ha as Low, Med and High, respectively) and three biofertilizer spray regimes (no spray, one spray and two sprays). All traits measured were significantly affected by the agricultural production system (CONV or ORG) and N rate, although trends in their interactions were inconsistent between years. In Y2, yield was greatest in treatments with high N rates and in the ORG system. Biofertilizer treatments had a negative to neutral effect on grain yield. Baking quality traits such as protein content, lactic acid solvent retention capacity and sedimentation value (SV) were consistently greater in the CONV system and increased with the higher N application rates. Similarly, biofertilizer application had no effect on predictive baking quality traits, except for SV in year 1 of the study, where it increased with two sprays. Loaf volume was consistently greater from wheat grown in CONV treatments. From these results, we conclude that further research is warranted to evaluate the potential for biofertilizers to enhance N uptake and affect bread baking quality or other end-use traits. Additional research may be especially useful in organic production systems where biologically based N fertilizers are utilized, and treatments were not negatively affected by biofertilizer applications. Such strategies may be needed to increase protein quantity and gluten quality to optimize winter wheat production for bread baking qualities in the southeastern USA
Impact of Nitrogen Rate in Conventional and Organic Production Systems on Yield and Bread Baking Quality of Soft Red Winter Wheat
Soft red winter wheat (SRW) is characterized by high yield and relatively low protein content. In Kentucky, there is growing demand from local artisan bread bakers for regionally produced flour, requiring production of grain with increased protein content and/or strength. The objective of this two-year field experiment was to evaluate the effect of nitrogen (N) management on five cultivars of winter wheat on yield and bread baking quality traits of modern and landrace SRW cultivars (Triticum aestivum L.). All five cultivars were evaluated using two N application rates in conventional and organic production systems. All traits measured were significantly affected by the agricultural production system and N rate, although plant height and other quality traits varied by study year. Significantly higher yields were achieved in the conventional system at a relatively low N rate (67.2 kg ha−1) in both study years (2017–2019) (p \u3c 0.01). Results were variable by cultivar and a locally bred, high-yielding cultivar (Pembroke 2014) had the highest lactic acid solvent retention capacity score and thousand kernel weight of the cultivars evaluated. In addition, a landrace cultivar (Purple Straw) had the highest grain N and plant height. A French soft wheat, Soissons, had the highest sedimentation value and Pembroke 2016 achieved the highest yield. The findings from this study suggest the possibility of attaining a desirable grain with quality traits of SRW wheat that meets the needs of local bread wheat production in Kentucky through improving the optimization of cultivar selection, N management and specific considerations for conventional and organic systems
Orbital dynamics of Cygnus X-3
Orbital-phased-resolved infrared spectra of Cygnus X-3 in outburst and
quiescence, including tomographic analysis, are presented. We confirm the
phasing of broad HeII and NV lines in quiescence, such that maximum blue shift
corresponds to the X-ray minimum at phase = 0.00 +/- 0.04. In outburst,
double-peaked HeI structures show a similar phasing with two significant
differences: (a) although varying in relative strength, there is continuous
line emission in blue and red peaks around the orbit, and (b) an absorption
component, ~1/4 of an orbit out of phase with the emission features, is
discerned. Doppler tomograms of the double-peaked profiles are consistent with
a disk-wind geometry, rotating at velocities of 1000 km/s. Regrettably, the
tomography algorithm will produce a similar ring structure from alternative
line sources if contaminated by overlying P Cygni profiles. This is certainly
the case in the strong 2.0587 micron HeI line, leading to an ambiguous solution
for the nature of double-peaked emission. The absorption feature, detected 1/4
of an orbit out of phase with the emission features, is consistent with an
origin in the He star wind and yields for the first time a plausible radial
velocity curve for the system. We directly derive the mass function of the
system, 0.027 M_sun. If we assume a neutron star accretor and adopt a high
orbital inclination, i > 60 degrees, we obtain a mass range for the He star of
5 M_sun < M_WR < 11 M_sun. Alternatively if the compact object is a black hole,
we estimate M_BH < 10 M_sun. We discuss the implications of these masses for
the nature and size of the binary system.Comment: Accepted for publication in ApJ main journa
Bright low mass eclipsing binary candidates observed by STEREO
Observations from the Heliospheric Imagers (HI-1) on both the STEREO
spacecraft have been analysed to search for bright low mass eclipsing binaries
(EBs) and potential brown dwarf transits and to determine the radii of the
companions. A total of 9 EB candidates have been found, ranging in brightness
from V=6.59 mag to V=11.3 mag, where the radius of the companion appears to be
less than 0.4 Rsol, with a diverse range of host temperatures, from 4074 K to
6925 K. Both components of one candidate, BD-07 3648, appear to be less than
0.4 Rsol and this represents a particularly interesting system for further
study. The shapes of the eclipses in some cases are not clear enough to be
certain they are total and the corresponding radii found should therefore be
considered as lower limits. The EBs reported in this paper have either been
newly found by the present analysis, or previously reported to be eclipsing by
our earlier STEREO/HI-1 results. One of the new objects has subsequently been
confirmed using archival SuperWASP data. This study was made possible by using
an improved matched filter extraction algorithm, which is described in this
paper.Comment: 11 pages, 6 figures, 2 tables, accepted for publication in MNRA
Reprocessing the Hipparcos data for evolved giant stars II. Absolute magnitudes for the R-type carbon stars
The Hipparcos Intermediate Astrometric Data for carbon stars have been
reprocessed using an algorithm which provides an objective criterion for
rejecting anomalous data points and constrains the parallax to be positive. New
parallax solutions have been derived for 317 cool carbon stars, mostly of types
R and N. In this paper we discuss the results for the R stars. The most
important result is that the early R stars (i.e., R0 - R3) have absolute
magnitudes and V-K colors locating them among red clump giants in the
Hertzsprung-Russell diagram. Stars with subtypes R4 - R9 tend to be cooler and
have similar luminosity to the N-type carbon stars, as confirmed by their
position in the (J-H, H-K) color-color diagram. The sample of early R-type
stars selected from the Hipparcos Catalogue appears to be approximately
complete to magnitude K_0 ~ 7, translating into a completeness distance of 600
pc if all R stars had M_K= -2 (400 pc if M_K= -1). With about 30 early R-type
stars in that volume, they comprise about 0.04% (0.14% for M_K= -1) of the red
clump stars in the solar neighborhood. Identification with the red clump
locates these stars at the helium core burning stage of stellar evolution,
while the N stars are on the asymptotic giant branch, where helium shell
burning occurs. The present analysis suggests that for a small fraction of the
helium core burning stars (far lower than the fraction of helium shell-burning
stars), carbon produced in the interior is mixed to the atmosphere in
sufficient quantities to form a carbon star.Comment: 11 pages, 6 figures, A&A Latex. To appear in A&
Persistence of Livestock Associated MRSA CC398 in Humans Is Dependent on Intensity of Animal Contact
INTRODUCTION: The presence of Livestock Associated MRSA (LA-MRSA) in humans is associated with intensity of animal contact. It is unknown whether the presence of LA-MRSA is a result of carriage or retention of MRSA-contaminated dust. We conducted a longitudinal study among 155 veal farmers in which repeated nasal and throat swabs were taken for MRSA detection. Periods with and without animal exposure were covered. METHODS: Randomly, 51 veal calf farms were visited from June-December 2008. Participants were asked to fill in questionnaires (n = 155) to identify potential risk factors for MRSA colonisation. Nasal and throat swabs were repeatedly taken from each participant for approximately 2 months. Swabs were analysed for MRSA and MSSA by selective bacteriological culturing. Spa-types of the isolates were identified and a ST398 specific PCR was performed. Data were analyzed using generalized estimation equations (GEE) to allow for correlated observations within individuals. RESULTS: Mean MRSA prevalence was 38% in farmers and 16% in family members. Presence of MRSA in farmers was strongly related to duration of animal contact and was strongly reduced in periods with absence of animal contact (-58%). Family members, especially children, were more often carriers when the farmer was a carrier (OR = 2,
Application of a Key Events Dose-Response Analysis to Nutrients: A Case Study with Vitamin A (Retinol)
The methodology used to establish tolerable upper intake levels (UL) for nutrients borrows heavily from risk assessment methods used by toxicologists. Empirical data are used to identify intake levels associated with adverse effects, and Uncertainty Factors (UF) are applied to establish ULs, which in turn inform public health decisions and standards. Use of UFs reflects lack of knowledge regarding the biological events that underlie response to the intake of a given nutrient, and also regarding the sources of variability in that response. In this paper, the Key Events Dose-Response Framework (KEDRF) is used to systematically consider the major biological steps that lead from the intake of the preformed vitamin A to excess systemic levels, and subsequently to increased risk of adverse effects. Each step is examined with regard to factors that influence whether there is progression toward the adverse effect of concern. The role of homeostatic mechanisms is discussed, along with the types of research needed to improve understanding of dose-response for vitamin A. This initial analysis illustrates the potential of the KEDRF as a useful analytical tool for integrating current knowledge regarding dose-response, generating questions that will focus future research efforts, and clarifying how improved knowledge and data could be used to reduce reliance on UFs
Period and chemical evolution of SC stars
The SC and CS stars are thermal-pulsing AGB stars with C/O ratio close to
unity. Within this small group, the Mira variable BH Cru recently evolved from
spectral type SC (showing ZrO bands) to CS (showing weak C2). Wavelet analysis
shows that the spectral evolution was accompanied by a dramatic period
increase, from 420 to 540 days, indicating an expanding radius. The pulsation
amplitude also increased. Old photographic plates are used to establish that
the period before 1940 was around 490 days. Chemical models indicate that the
spectral changes were caused by a decrease in stellar temperature, related to
the increasing radius. There is no evidence for a change in C/O ratio. The
evolution in BH Cru is unlikely to be related to an on-going thermal pulse.
Periods of the other SC and CS stars, including nine new periods, are
determined. A second SC star, LX Cyg, also shows evidence for a large increase
in period, and one further star shows a period inconsistent with a previous
determination. Mira periods may be intrinsically unstable for C/O ~ 1; possibly
because of a feedback between the molecular opacities, pulsation amplitude, and
period. LRS spectra of 6 SC stars suggest a feature at wavelength > 15 micron,
which resembles one recently attributed to the iron-sulfide troilite. Chemical
models predict a large abundance of FeS in SC stars, in agreement with the
proposed association.Comment: 14 pages, 20 figures. MNRAS, 2004, accepted for publication. Janet
Mattei, one of the authors, died on 22 March, 2004. This paper is dedicated
to her memor
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