376 research outputs found
Bringing Farm Advisors into the Sustainability Conversation: Results from a Nitrogen Workshop in the U.S. Midwest
Increasingly, farmers are looking to private sector advisors to inform their nitrogen decisions, but little is known about these important actors. We held a Sustainable Nitrogen Roundtable workshop to bring together important groups—private sector farm advisors, Extension educators, scientists, and farmers—to discuss new research and more sustainable use of nitrogen in midwestern cropping systems. We gained important insights by reaching outside academia and including private sector farm advisors as valued participants. Ninety percent of participants found that their understanding of varied viewpoints on nitrogen management improved, and an equal proportion would recommend such a workshop to a colleague
Quantitative and qualitative estimation of atherosclerotic plaque burden in vivo at 7T MRI using Gadospin F in comparison to en face preparation evaluated in ApoE KO
Background The aim of the study was to quantify atherosclerotic plaque burden
by volumetric assessment and T1 relaxivity measurement at 7T MRI using
Gadospin F (GDF) in comparison to en face based measurements. Methods and
results 9-weeks old ApoE-/- (n = 5 for each group) and wildtype mice (n = 5)
were set on high fat diet (HFD). Progression group received MRI at 9, 13, 17
and 21 weeks after HFD initiation. Regression group was reswitched to chow
diet (CD) after 13 weeks HFD and monitored with MRI for 12 weeks. MRI was
performed before and two hours after iv injection of GDF (100 μmol/kg) at 7T
(Clinscan, Bruker) acquiring a 3D inversion recovery gradient echo sequence
and T1 Mapping using Saturation Recovery sequences. Subsequently, aortas were
prepared for en face analysis using confocal microscopy. Total plaque volume
(TPV) and T1 relaxivity were estimated using ImageJ (V. 1.44p, NIH, USA). 2D
and 3D en face analysis showed a strong and exponential increase of plaque
burden over time, while plaque burden in regression group was less pronounced.
Correspondent in vivo MRI measurements revealed a more linear increase of TPV
and T1 relaxivity for regression group. A significant correlation was observed
between 2D and 3D en face analysis (r = 0.79; p<0.001) as well as between 2D /
3D en face analysis and MRI (r = 0.79; p<0.001; r = 0.85; p<0.001) and delta
R1 (r = 0.79; p<0.001; r = 0.69; p<0.01). Conclusion GDF-enhanced in vivo MRI
is a powerful non-invasive imaging technique in mice allowing for reliable
estimation of atherosclerotic plaque burden, monitoring of disease progression
and regression in preclinical studies
Non-thermal radio emission from O-type stars. IV. Cyg OB2 No. 8A
We study the non-thermal radio emission of the binary Cyg OB2 No. 8A, to see
if it is variable and if that variability is locked to the orbital phase. We
investigate if the synchrotron emission generated in the colliding-wind region
of this binary can explain the observations and we verify that our proposed
model is compatible with the X-ray data. We use both new and archive radio data
from the Very Large Array (VLA) to construct a light curve as a function of
orbital phase. We also present new X-ray data that allow us to improve the
X-ray light curve. We develop a numerical model for the colliding-wind region
and the synchrotron emission it generates. The model also includes free-free
absorption and emission due to the stellar winds of both stars. In this way we
construct artificial radio light curves and compare them with the observed one.
The observed radio fluxes show phase-locked variability. Our model can explain
this variability because the synchrotron emitting region is not completely
hidden by the free-free absorption. In order to obtain a better agreement for
the phases of minimum and maximum flux we need to use stellar wind parameters
for the binary components which are somewhat different from typical values for
single stars. We verify that the change in stellar parameters does not
influence the interpretation of the X-ray light curve. Our model has trouble
explaining the observed radio spectral index. This could indicate the presence
of clumping or porosity in the stellar wind, which - through its influence on
both the Razin effect and the free-free absorption - can considerably influence
the spectral index. Non-thermal radio emitters could therefore open a valuable
pathway to investigate the difficult issue of clumping in stellar winds.Comment: 19 pages, 10 figures, accepted by A&
Consensus Guidelines for Advancing Coral Holobiont Genome and Specimen Voucher Deposition
Coral research is being ushered into the genomic era. To fully capitalize on the potential discoveries from this genomic revolution, the rapidly increasing number of high-quality genomes requires effective pairing with rigorous taxonomic characterizations of specimens and the contextualization of their ecological relevance. However, to date there is no formal framework that genomicists, taxonomists, and coral scientists can collectively use to systematically acquire and link these data. Spurred by the recently announced “Coral symbiosis sensitivity to environmental change hub” under the “Aquatic Symbiosis Genomics Project” - a collaboration between the Wellcome Sanger Institute and the Gordon and Betty Moore Foundation to generate gold-standard genome sequences for coral animal hosts and their associated Symbiodiniaceae microalgae (among the sequencing of many other symbiotic aquatic species) - we outline consensus guidelines to reconcile different types of data. The metaorganism nature of the coral holobiont provides a particular challenge in this context and is a key factor to consider for developing a framework to consolidate genomic, taxonomic, and ecological (meta)data. Ideally, genomic data should be accompanied by taxonomic references, i.e., skeletal vouchers as formal morphological references for corals and strain specimens in the case of microalgal and bacterial symbionts (cultured isolates). However, exhaustive taxonomic characterization of all coral holobiont member species is currently not feasible simply because we do not have a comprehensive understanding of all the organisms that constitute the coral holobiont. Nevertheless, guidelines on minimal, recommended, and ideal-case descriptions for the major coral holobiont constituents (coral animal, Symbiodiniaceae microalgae, and prokaryotes) will undoubtedly help in future referencing and will facilitate comparative studies. We hope that the guidelines outlined here, which we will adhere to as part of the Aquatic Symbiosis Genomics Project sub-hub focused on coral symbioses, will be useful to a broader community and their implementation will facilitate cross- and meta-data comparisons and analyses.CV acknowledges funding from the German Research Foundation (DFG), grants 433042944 and 458901010. Open Access publication fees are covered by an institutional agreement of the University of Konstanz
A Unifying Mechanism for Mitochondrial Superoxide Production during Ischemia-Reperfusion Injury.
Ischemia-reperfusion (IR) injury occurs when blood supply to an organ is disrupted--ischemia--and then restored--reperfusion--leading to a burst of reactive oxygen species (ROS) from mitochondria. It has been tacitly assumed that ROS production during IR is a non-specific consequence of oxygen interacting with dysfunctional mitochondria upon reperfusion. Recently, this view has changed, suggesting that ROS production during IR occurs by a defined mechanism. Here we survey the metabolic factors underlying IR injury and propose a unifying mechanism for its causes that makes sense of the huge amount of disparate data in this area and provides testable hypotheses and new directions for therapies.Work in our laboratories is supported by the Medical Research Council (UK) and the British Heart Foundation. E.T.C. is supported by a Human Frontiers Science Program fellowship.This is the author accepted manuscript. The final version is available from Cell Press via http://dx.doi.org/10.1016/j.cmet.2015.12.00
Biomarkers Signal Contaminant Effects on the Organs of English Sole (Parophrys vetulus) from Puget Sound
Fish living in contaminated environments accumulate toxic chemicals in their tissues. Biomarkers are needed to identify the resulting health effects, particularly focusing on early changes at a subcellular level. We used a suite of complementary biomarkers to signal contaminant-induced changes in the DNA structure and cellular physiology of the livers and gills of English sole (Parophrys vetulus). These sediment-dwelling fish were obtained from the industrialized lower Duwamish River (DR) in Seattle, Washington, and from Quartermaster Harbor (QMH), a relatively clean reference site in south Puget Sound. Fourier transform–infrared (FT-IR) spectroscopy, liquid chromatography/mass spectrometry (LC/MS), and gas chromatography/mass spectrometry (GC/MS) identified potentially deleterious alterations in the DNA structure of the DR fish livers and gills, compared with the QMH fish. Expression of CYP1A (a member of the cytochrome P450 multigene family of enzymes) signaled changes in the liver associated with the oxidation of organic xenobiotics, as previously found with the gill. The FT-IR models demonstrated that the liver DNA of the DR fish had a unique structure likely arising from exposure to environmental chemicals. Analysis by LC/MS and GC/MS showed higher concentrations of DNA base lesions in the liver DNA of the DR fish, suggesting that these base modifications contributed to this discrete DNA structure. A comparable analysis by LC/MS and GC/MS of base modifications provided similar results with the gill. The biomarkers described are highly promising for identifying contaminant-induced stresses in fish populations from polluted and reference sites and, in addition, for monitoring the progress of remedial actions
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