107 research outputs found
Responses to Selection for Partial Resistance to Crown Rust in Oat
Crown rust, caused by the fungal pathogen, Puccinia coronata Corda var. avenae W.P. Fraser Ledingham, reduces kernel quality and grain yield in oat (Avena sativa L.). Partial resistance is considered to be a durable form of rust resistance. This study sought to evaluate the feasibility of simultaneously improving partial resistance to crown rust, grain yield, and seed weight in an oat population, and to estimate predicted and realized heritabilities for area under disease progress curve (AUDPC) and genetic correlations between AUDPC and agronomic traits in both crown rust-inoculated and fungicide-treated plots. A single cycle of selection for partial resistance to crown rust was performed. The initial (C0) and selected (C1) generations were evaluated in a field experiment in 2001 and 2002 at two Iowa locations. Selection on an index increased the levels of crown rust resistance, grain yield, and seed weight in crown rustāinoculated plots, and seed weight in fungicide-treated plots. However, the change for the grain yield in fungicide-treated plots was not significant. In both C0 and C1 populations, AUDPC was highly heritable (H = 0.77 and 0.78 respectively), and was favorably correlated with grain yield, seed weight, and test weight measured in inoculated plots. Realized heritabilities for all traits except grain yield under fungicide treatment were consistent with predicted heritabilities. Our results suggested that index selection could increase levels of crown rust resistance, grain yield, and seed weight simultaneously
Early Ultraviolet, Optical and X-Ray Observations of the Type IIP SN 2005cs in M51 with Swift
We report early photospheric-phase observations of the Type IIP Supernova
(SN) 2005cs obtained by Swift's Ultraviolet-Optical and X-Ray Telescopes.
Observations started within two days of discovery and continued regularly for
three weeks. During this time the V-band magnitude remained essentially
constant, while the UV was initially bright but steadily faded until below the
brightness of an underlying UV-bright HII region. This UV decay is similar to
SNe II observed by the International Ultraviolet Explorer. UV grism spectra
show the P-Cygni absorption of MgII 2798A, indicating a photospheric origin of
the UV flux. Based on non-LTE model atmosphere calculations with the CMFGEN
code, we associate the rapid evolution of the UV flux with the cooling of the
ejecta, the peak of the spectral energy distribution (SED) shifting from ~700A
on June 30th to ~1200A on July 5th. Furthermore, the corresponding
recombination of the ejecta, e.g., the transition from FeIII to FeII, induces
considerable strengthening of metal line-blanketing at and above the
photosphere, blocking more effectively this fading UV flux. SN2005cs was not
detected in X-rays, and the upper limit to the X-ray luminosity yields a limit
to the mass loss rate of the progenitor of about 10^-5 solar masses per year.
Overall, Swift presents a unique opportunity to capture the early and fast
evolution of Type II SNe in the UV, providing additional constraints on the
reddening, the SED shortward of 4000A, and the ionization state and temperature
of the photon-decoupling regions.Comment: 15 pages, 6 figures. Accepted for publication by Astrophysical
Journa
The First Provenance Challenge
The first Provenance Challenge was set up in order to provide a forum for the community to help understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a Functional Magnetic Resonance Imaging workflow was defined, which participants had to either simulate or run in order to produce some provenance representation, from which a set of identified queries had to be implemented and executed. Sixteen teams responded to the challenge, and submitted their inputs. In this paper, we present the challenge workflow and queries, and summarise the participants contributions
Reconstruction of the Talkeetna intraoceanic arc of Alaska through thermobarometry
Author Posting. Ā© American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): B03204, doi:10.1029/2007JB005208.The Talkeetna arc is one of two intraoceanic arcs where much of the section from the upper mantle through the volcanic carapace is well exposed. We reconstruct the vertical section of the Talkeetna arc by determining the (re)crystallization pressures at various structural levels. The thermobarometry shows that the tonalites and quartz diorites intruded at ā¼5ā9 km into a volcanic section estimated from stratigraphy to be 7 km thick. The shallowest, Tazlina and Barnette, gabbros crystallized at ā¼17ā24 km; the Klanelneechena Klippe crystallized at ā¼24ā26 km; and the base of the arc crystallized at ā¼35 km depth. The arc had a volcanic:plutonic ratio of ā¼1:3ā1:4. However, many or most of the felsic plutonic rocks may represent crystallized liquids rather than cumulates so that the liquid:cumulate ratio might be 1:2 or larger. The current 5- to 7-km structural thickness of the plutonic section of the arc is ā¼15ā30% of the original 23- to 28-km thickness. The bulk composition of the original Talkeetna arc section was ā¼51ā58 wt % SiO2.Funded by NSF EAR-9910899
Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle Tracking Echocardiography in Preterm Infants over the First Year of Age
BACKGROUND:
The aim of this study was to determine the maturational changes in systolic ventricular strain mechanics by two-dimensional speckle-tracking echocardiography in extremely preterm neonates from birth to 1 year of age and discern the impact of common cardiopulmonary abnormalities on the deformation measures.
METHODS:
In a prospective multicenter study of 239 extremely preterm infants (<29 weeks gestation at birth), left ventricular (LV) global longitudinal strain (GLS) and global longitudinal systolic strain rate (GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricular (RV) free wall longitudinal strain and strain rate, and segmental longitudinal strain in the RV free wall, LV free wall, and IVS were serially measured on days 1, 2, and 5 to 7, at 32 and 36 weeks postmenstrual age, and at 1 year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately.
RESULTS:
In uncomplicated preterm infants (n = 103 [48%]), LV GLS and GLSRs remained unchanged from days 5 to 7 to 1 year CA (P = .60 and P = .59). RV free wall longitudinal strain, RV free wall longitudinal strain rate, and IVS GLS and GLSRs significantly increased over the same time period (P < .01 for all measures). A significant base-to-apex (highest to lowest) segmental longitudinal strain gradient (P < .01) was seen in the RV free wall and a reverse apex-to-base gradient (P < .01) in the LV free wall. In infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]), RV free wall longitudinal strain and IVS GLS were significantly lower (P < .01), LV GLS and GLSRs were similar (P = .56), and IVS segmental longitudinal strain persisted as an RV-dominant base-to-apex gradient from 32 weeks postmenstrual age to 1 year CA.
CONCLUSIONS:
This study tracks the maturational patterns of global and regional deformation by two-dimensional speckle-tracking echocardiography in extremely preterm infants from birth to 1 year CA. The maturational patterns are ventricular specific. Bronchopulmonary dysplasia and pulmonary hypertension leave a negative impact on RV and IVS strain, while LV strain remains stable
Using Quantitative Spectroscopic Analysis to Determine the Properties and Distances of Type II-Plateau Supernovae: SNe 2005cs and 2006bp
We analyze the Type II Plateau supernovae (SN II-P) 2005cs and 2006bp with
the non-LTE model atmosphere code CMFGEN. We fit 13 spectra in the first month
for SN 2005cs and 18 for SN 2006bp. {\sl Swift} ultraviolet photometry and
ground-based optical photometry calibrate each spectrum. Our analysis shows
both objects were discovered less than 3 days after they exploded, making these
the earliest SN II-P spectra ever studied. They reveal broad and very weak
lines from highly-ionized fast ejecta with an extremely steep density profile.
We identify He{\sc ii} 4686\AA emission in the SN 2006bp ejecta. Days later,
the spectra resemble the prototypical Type II-P SN 1999em, which had a
supergiant-like photospheric composition. Despite the association of SN 2005cs
with possible X-ray emission, the emergent UV and optical light comes from the
photosphere, not from circumstellar emission.
We surmise that the very steep density fall-off we infer at early times may
be a fossil of the combined actions of the shock wave passage and radiation
driving at shock breakout. Based on tailored CMFGEN models, the direct-fitting
technique and the Expanding Photosphere Method both yield distances and
explosion times that agree within a few percent. We derive a distance to NGC
5194, the host of SN 2005cs, of 8.90.5 Mpc and 17.50.8 Mpc for SN
2006bp in NGC 3953. The luminosity of SN 2006bp is 1.5 times that of SN 1999em,
and 6 times that of SN 2005cs. Reliable distances to Type II-P supernovae that
do not depend on a small range in luminosity provide an independent route to
the Hubble Constant and improved constraints on other cosmological parameters.Comment: 27 pages, 16 figures, 11 tables, accepted to ApJ, high-resolution of
the paper available at
http://hermes.as.arizona.edu/~luc/snIIP/sn05cs_06bp.ps.g
Deeper knowledge of shallow waters: reviewing the invertebrate fauna of southern African temporary wetlands
Temporary lentic wetlands are becoming
increasingly recognised for their collective role in
contributing to biodiversity at the landscape scale. In
southern Africa, a region with a high density of such
wetlands, information characterising the fauna of
these systems is disparate and often obscurely published.
Here we provide a collation and synthesis of
published research on the aquatic invertebrate fauna
inhabiting temporary lentic wetlands of the region. We
expose the poor taxonomic knowledge of most groups,
which makes it difficult to comment on patterns of
richness and endemism. Only a few groups (e.g. large
branchiopods, ostracods, copepods and cladocerans)
appear to reach higher richness and/or endemicity in
temporary wetlands compared to their permanent
wetland counterparts. IUCN Red List information is
lacking for most taxa, thus making it difficult to
comment on the conservation status of much of the
invertebrate fauna. However, except for a few specialist
groups, many of the taxa inhabiting these
environments appear to be habitat generalists that
opportunistically exploit these waterbodies and this is hypothesised as one of the reasons why endemism
appears to be low for most taxa. Given that taxonomy
underpins ecology, the urgent need for more foundational
taxonomic work on these systems becomes
glaringly apparent
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