2,553 research outputs found

    Use of a Producer Survey to Reconcile Differences in Experiment Station Yield Estimates

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    Average producer practice reveals that the expected returns are greater from dual-purpose wheat grown for both forage and grain than for grain-only wheat. Variety trials report an 11 bushel per acre yield advantage and hence economic advantage for grain-only. Research was conducted to reconcile the inconsistency.direct elicitation method, dual-purpose, simulation, stocker steers, survey, triangular distribution, wheat, Farm Management, Livestock Production/Industries, Q10, Q12,

    Maternal and fetal risk factors for stillbirth : population based study

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    Objective: To assess the main risk factors associated with stillbirth in a multiethnic English maternity population. Design: Cohort study. Setting: National Health Service region in England. Population: 92 218 normally formed singletons including 389 stillbirths from 24 weeks of gestation, delivered during 2009-11. Main outcome measure: Risk of stillbirth. Results: Multivariable analysis identified a significant risk of stillbirth for parity (para 0 and para ≄3), ethnicity (African, African-Caribbean, Indian, and Pakistani), maternal obesity (body mass index ≄30), smoking, pre-existing diabetes, and history of mental health problems, antepartum haemorrhage, and fetal growth restriction (birth weight below 10th customised birthweight centile). As potentially modifiable risk factors, maternal obesity, smoking in pregnancy, and fetal growth restriction together accounted for 56.1% of the stillbirths. Presence of fetal growth restriction constituted the highest risk, and this applied to pregnancies where mothers did not smoke (adjusted relative risk 7.8, 95% confidence interval 6.6 to 10.9), did smoke (5.7, 3.6 to 10.9), and were exposed to passive smoke only (10.0, 6.6 to 15.8). Fetal growth restriction also had the largest population attributable risk for stillbirth and was fivefold greater if it was not detected antenatally than when it was (32.0% v 6.2%). In total, 195 of the 389 stillbirths in this cohort had fetal growth restriction, but in 160 (82%) it had not been detected antenatally. Antenatal recognition of fetal growth restriction resulted in delivery 10 days earlier than when it was not detected: median 270 (interquartile range 261-279) days v 280 (interquartile range 273-287) days. The overall stillbirth rate (per 1000 births) was 4.2, but only 2.4 in pregnancies without fetal growth restriction, increasing to 9.7 with antenatally detected fetal growth restriction and 19.8 when it was not detected. Conclusion: Most normally formed singleton stillbirths are potentially avoidable. The single largest risk factor is unrecognised fetal growth restriction, and preventive strategies need to focus on improving antenatal detection

    Modeling truncated pixel values of faint reflections in MicroED images.

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    The weak pixel counts surrounding the Bragg spots in a diffraction image are important for establishing a model of the background underneath the peak and estimating the reliability of the integrated intensities. Under certain circumstances, particularly with equipment not optimized for low-intensity measurements, these pixel values may be corrupted by corrections applied to the raw image. This can lead to truncation of low pixel counts, resulting in anomalies in the integrated Bragg intensities, such as systematically higher signal-to-noise ratios. A correction for this effect can be approximated by a three-parameter lognormal distribution fitted to the weakly positive-valued pixels at similar scattering angles. The procedure is validated by the improved refinement of an atomic model against structure factor amplitudes derived from corrected micro-electron diffraction (MicroED) images

    Canola-Wheat Rotation versus Continuous Wheat for the Southern Plains

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    Crop rotations are not common in the wheat belt of the Southern Plains. After years of continuous wheat, weeds have become increasingly difficult and expensive to manage. Yield data were elicited from farmers and used to determine if canola-wheat-wheat rotations are economically competitive with continuous wheat in the region.crop rotation, wheat, canola, elicited yield distributions, Crop Production/Industries, Farm Management, Q10, Q12,

    MicroED data collection and processing.

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    MicroED, a method at the intersection of X-ray crystallography and electron cryo-microscopy, has rapidly progressed by exploiting advances in both fields and has already been successfully employed to determine the atomic structures of several proteins from sub-micron-sized, three-dimensional crystals. A major limiting factor in X-ray crystallography is the requirement for large and well ordered crystals. By permitting electron diffraction patterns to be collected from much smaller crystals, or even single well ordered domains of large crystals composed of several small mosaic blocks, MicroED has the potential to overcome the limiting size requirement and enable structural studies on difficult-to-crystallize samples. This communication details the steps for sample preparation, data collection and reduction necessary to obtain refined, high-resolution, three-dimensional models by MicroED, and presents some of its unique challenges

    Benthic Foraminiferal response to sea level change in the mixed siliciclastic-carbonate system of southern Ashmore Trough (Gulf of Papua)

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    Ashmore Trough in the western Gulf of Papua (GoP) represents an outstanding modern example of a tropical mixed siliciclastic-carbonate depositional system where significant masses of both river-borne silicates and bank-derived neritic carbonates accumulate. In this study, we examine how benthic foraminiferal populations within Ashmore Trough vary in response to sea level–driven paleoenvironmental changes, particularly organic matter and sediment supply. Two 11.3-m-long piston cores and a trigger core were collected from the slope of Ashmore Trough and dated using radiocarbon and oxygen isotope measurements of planktic foraminifera. Relative abundances, principal component analyses, and cluster analyses of benthic foraminiferal assemblages in sediment samples identify three distinct assemblages whose proportions changed over time. Assemblage 1, with high abundances of Uvigerina peregrina and Bolivina robusta, dominated between ∌83 and 70 ka (early regression); assemblage 2, with high abundances of Globocassidulina subglobosa, dominated between ∌70 and 11 ka (late regression through lowstand and early transgression); and assemblage 3, with high abundances of neritic benthic species such as Planorbulina mediterranensis, dominated from ∌11 ka to the present (late transgression through early highstand). Assemblage 1 represents heightened organic carbon flux or lowered bottom water oxygen concentration, and corresponds to a time of maximum siliciclastic fluxes to the slope with falling sea level. Assemblage 2 reflects lowered organic carbon flux or elevated bottom water oxygen concentration, and corresponds to an interval of lowered siliciclastic fluxes to the slope due to sediment bypass during sea level lowstand. Assemblage 3 signals increased off-shelf delivery of neritic carbonates, likely when carbonate productivity on the outer shelf (Great Barrier Reef) increased significantly when it was reflooded. Benthic foraminiferal assemblages in the sediment sink (slopes of Ashmore Trough) likely respond to the amount and type of sediment supplied from the proximal source (outer GoP shelf)

    A dominant mutation in a neuronal acetylcholine receptor subunit leads to motor neuron degeneration in Caenorhabditis elegans

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    Inappropriate or excessive activation of ionotropic receptors can have dramatic consequences for neuronal function and, in many instances, leads to cell death. In Caenorhabditis elegans, nicotinic acetylcholine receptor (nAChR) subunits are highly expressed in a neural circuit that controls movement. Here, we show that heteromeric nAChRs containing the acr-2 subunit are diffusely localized in the processes of excitatory motor neurons and act to modulate motor neuron activity. Excessive signaling through these receptors leads to cell-autonomous degeneration of cholinergic motor neurons and paralysis. C. elegans double mutants lacking calreticulin and calnexin-two genes previously implicated in the cellular events leading to necrotic-like cell death (Xu et al. 2001)-are resistant to nAChR-mediated toxicity and possess normal numbers of motor neuron cell bodies. Nonetheless, excess nAChR activation leads to progressive destabilization of the motor neuron processes and, ultimately, paralysis in these animals. Our results provide new evidence that chronic activation of ionotropic receptors can have devastating degenerative effects in neurons and reveal that ion channel-mediated toxicity may have distinct consequences in neuronal cell bodies and processes

    Microbial community transcriptional networks are conserved in three domains at ocean basin scales

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    Planktonic microbial communities in the ocean are typically dominated by several cosmopolitan clades of Bacteria, Archaea, and Eukarya characterized by their ribosomal RNA gene phylogenies and genomic features. Although the environments these communities inhabit range from coastal to open ocean waters, how the biological dynamics vary between such disparate habitats is not well known. To gain insight into the differential activities of microbial populations inhabiting different oceanic provinces we compared the daily metatranscriptome profiles of related microbial populations inhabiting surface waters of both a coastal California upwelling region (CC) as well as the oligotrophic North Pacific Subtropical Gyre (NPSG). Transcriptional networks revealed that the dominant photoautotrophic microbes in each environment (Ostreococcus in CC, Prochlorococcus in NPSG) were central determinants of overall community transcriptome dynamics. Furthermore, heterotrophic bacterial clades common to both ecosystems (SAR11, SAR116, SAR86, SAR406, and Roseobacter) displayed conserved, genome-wide inter- and intrataxon transcriptional patterns and diel cycles. Populations of SAR11 and SAR86 clades in particular exhibited tightly coordinated transcriptional patterns in both coastal and pelagic ecosystems, suggesting that specific biological interactions between these groups are widespread in nature. Our results identify common diurnally oscillating behaviors among diverse planktonic microbial species regardless of habitat, suggesting that highly conserved temporally phased biotic interactions are ubiquitous among planktonic microbial communities worldwide.Gordon and Betty Moore Foundation (3777)National Science Foundation (U.S.) (Grant EF0424599)Simons Foundation (Simons Collaboration on Ocean Processes and Ecology
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