370 research outputs found

    Influence of nitrogen fertilization on winter wheat rooting patterns and soil water extraction

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    Non-Peer ReviewedA partial excavation technique, called the profile wall method, was utilized in 1985 and 1986 to investigate effects of ammonium nitrate additions on rooting patterns of Norstar winter wheat (Triticum aestivum L.). Additional nitrogen was found to increase root growth, especially at tillering. Increases in soil water extraction were measured at the same time indicating a positive relationship between root density and soil water utilization. Placement of the fertilizer in mid-row bands at seeding time did not change crop rooting patterns compared to spring broadcast nitrogen applications. Fall fertilization was actually less effective with respect to protein yield; broadcast applied treatments generally had higher grain yields and higher protein concentration. Roots of winter wheat grew to an average 120 cm depth. Nitrogen fertilization did not affect final root depth. Environmental factors appeared to be important in determining root depth. Soil moisture limitations were observed at several locations in 1986

    Is ESN releasing fast enough to supply winter wheat nitrogen demand?

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    Non-Peer ReviewedThe purpose of this study is to investigate nitrogen release from various split rate applications of seed-placed environmentally smart nitrogen (ESN) and spring-applied dribble banded Agrotain-UAN (urea and ammonium nitrate solution) and broadcast Agrotain-urea in winter wheat. Cool spring soil conditions have the potential to limit nitrogen (N) release from ESN potentially limiting grain yield potential. Plant root simulator (PRS™) probes were used to monitor N soil supply. It was discovered that N supply did not vary significantly between the split-rate treatments. There were also no significant differences between grain yield and protein content. These results suggest that N release from ESN was not limited by cool spring temperatures and allowed plant vigour similar to traditional spring-applied methods

    Barriers to supportive care during the Ebola virus disease outbreak in West Africa: Results of a qualitative study

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    © 2018 Loignon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background During the 2013–2016 West Africa Ebola outbreak, supportive care was the only non-experimental treatment option for patients with Ebola virus disease (EVD). However, providing care that would otherwise be routine for most clinical settings in the context of a highly contagious and lethal pathogen is much more challenging. The objective of this study was to document and deepen understanding of barriers to provision of supportive care in Ebola treatment units (ETUs) as perceived by those involved in care delivery during the outbreak. Methods This qualitative study consisted of 29 in-depth semi-structured interviews with stakeholders (decision-makers, physicians, nurses) involved in patient care delivery during the outbreak. Analysis consisted of interview debriefing and team-based transcript coding in NVivo10 software using thematic analysis. Findings Participants emphasized three interconnected barriers to providing high-quality supportive care during the outbreak: 1) lack of material and human resources in ETUs; 2) ETU organizational structure limiting the provision of supportive clinical care; and 3) delayed and poorly coordinated policies limiting the effectiveness of global and national responses. Participants also noted the ethical complexities of defining and enacting best clinical practices in low-income countries. They noted tension between, on one hand, scaling up minimal care and investing in clinical care preparedness to a level sustainable in West Africa and, on the other, providing a higher level of supportive care, which in low-resource health systems would require important investments. Conclusion Our findings identified potentially modifiable barriers to the delivery of supportive care to patients with EVD in West Africa. Addressing these in the inter-outbreak period will be useful to improve patient care and outcomes during inevitable future outbreaks. Promoting community trust and engagement through long-term capacity building of the healthcare workforce and infrastructure would increase both health system resilience and ability to handle other outbreaks of emerging diseases

    Dimer coverings on the Sierpinski gasket with possible vacancies on the outmost vertices

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    We present the number of dimers Nd(n)N_d(n) on the Sierpinski gasket SGd(n)SG_d(n) at stage nn with dimension dd equal to two, three, four or five, where one of the outmost vertices is not covered when the number of vertices v(n)v(n) is an odd number. The entropy of absorption of diatomic molecules per site, defined as SSGd=limnlnNd(n)/v(n)S_{SG_d}=\lim_{n \to \infty} \ln N_d(n)/v(n), is calculated to be ln(2)/3\ln(2)/3 exactly for SG2(n)SG_2(n). The numbers of dimers on the generalized Sierpinski gasket SGd,b(n)SG_{d,b}(n) with d=2d=2 and b=3,4,5b=3,4,5 are also obtained exactly. Their entropies are equal to ln(6)/7\ln(6)/7, ln(28)/12\ln(28)/12, ln(200)/18\ln(200)/18, respectively. The upper and lower bounds for the entropy are derived in terms of the results at a certain stage for SGd(n)SG_d(n) with d=3,4,5d=3,4,5. As the difference between these bounds converges quickly to zero as the calculated stage increases, the numerical value of SSGdS_{SG_d} with d=3,4,5d=3,4,5 can be evaluated with more than a hundred significant figures accurate.Comment: 35 pages, 20 figures and 1 tabl

    At the edge of intonation: the interplay of utterance-final F0 movements and voiceless fricative sounds

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    The paper is concerned with the 'edge of intonation' in a twofold sense. It focuses on utterance-final F0 movements and crosses the traditional segment-prosody divide by investigating the interplay of F0 and voiceless fricatives in speech production. An experiment was performed for German with four types of voiceless fricatives: /f/, /s/, /ʃ/ and /x/. They were elicited with scripted dialogues in the contexts of terminal falling statement and high rising question intonations. Acoustic analyses show that fricatives concluding the high rising question intonations had higher mean centres of gravity (CoGs), larger CoG ranges and higher noise energy levels than fricatives concluding the terminal falling statement intonations. The different spectral-energy patterns are suitable to induce percepts of a high 'aperiodic pitch' at the end of the questions and of a low 'aperiodic pitch' at the end of the statements. The results are discussed with regard to the possible existence of 'segmental intonation' and its implication for F0 truncation and the segment-prosody dichotomy, in which segments are the alleged troublemakers for the production and perception of intonation

    An Institutional Theory perspective on sustainable practices across the dairy supply chain

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    AbstractThe need for sustainable practices in the food supply chain, particularly in the area of energy reduction, is becoming acute. The food industry currently has to contend with multiple competing pressures alongside the new challenges of sustainable production. We applied Institutional Theory to explore the role of supermarkets in the development of legitimate sustainable practices across the dairy supply chains. The paper focuses on dairy supply chain organizations and their consumption of energy. We conducted 70 semi-structured telephone interviews with various stakeholders across the supply chain. Findings revealed that the majority of actors in the supply chain identified supermarkets as the dominant player, and that the supermarkets exert pressure on other smaller organizations across the supply chain. Although some organizations wished to pursue a sustainable agenda through integrating new rules and legitimate practices within their own organization, the dominant logic appeared to be one of cost reduction and profit maximization. There was also evidence that supermarkets and other large organizations attempt to replicate publicly available information on green successes for image purposes. We conclude that the dominant logic of cost reduction is so well established that challenging the dominant logic may prove difficult. The challenge is therefore to complement the dominant logic with sustainable practices across the whole supply chain, a role Government needs to play. This will require a broader more systemic approach to encouraging sustainable practices including investment and financing practices, so that all members of the dairy supply chain can co-operate and contribute to energy reduction

    Gadoxetate-enhanced abbreviated MRI is highly accurate for hepatocellular carcinoma screening.

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    The primary objective was to compare the performance of 3 different abbreviated MRI (AMRI) sets extracted from a complete gadoxetate-enhanced MRI obtained for hepatocellular carcinoma (HCC) screening. Secondary objective was to perform a preliminary cost-effectiveness analysis, comparing each AMRI set to published ultrasound performance for HCC screening in the USA. This retrospective study included 237 consecutive patients (M/F, 146/91; mean age, 58 years) with chronic liver disease who underwent a complete gadoxetate-enhanced MRI for HCC screening in 2017 in a single institution. Two radiologists independently reviewed 3 AMRI sets extracted from the complete exam: non-contrast (NC-AMRI: T2-weighted imaging (T2wi)+diffusion-weighted imaging (DWI)), dynamic-AMRI (Dyn-AMRI: T2wi+DWI+dynamic T1wi), and hepatobiliary phase AMRI (HBP-AMRI: T2wi+DWI+T1wi during the HBP). Each patient was classified as HCC-positive/HCC-negative based on the reference standard, which consisted in all available patient data. Diagnostic performance for HCC detection was compared between sets. Estimated set characteristics, including historical ultrasound data, were incorporated into a microsimulation model for cost-effectiveness analysis. The reference standard identified 13/237 patients with HCC (prevalence, 5.5%; mean size, 33.7 ± 30 mm). Pooled sensitivities were 61.5% for NC-AMRI (95% confidence intervals, 34.4-83%), 84.6% for Dyn-AMRI (60.8-95.1%), and 80.8% for HBP-AMRI (53.6-93.9%), without difference between sets (p range, 0.06-0.16). Pooled specificities were 95.5% (92.4-97.4%), 99.8% (98.4-100%), and 94.9% (91.6-96.9%), respectively, with a significant difference between Dyn-AMRI and the other sets (p < 0.01). All AMRI methods were effective compared with ultrasound, with life-year gain of 3-12 months against incremental costs of US$ < 12,000. NC-AMRI has limited sensitivity for HCC detection, while HBP-AMRI and Dyn-AMRI showed excellent sensitivity and specificity, the latter being slightly higher for Dyn-AMRI. Cost-effectiveness estimates showed that AMRI is effective compared with ultrasound. • Comparison of different abbreviated MRI (AMRI) sets reconstructed from a complete gadoxetate MRI demonstrated that non-contrast AMRI has low sensitivity (61.5%) compared with contrast-enhanced AMRI (80.8% for hepatobiliary phase AMRI and 84.6% for dynamic AMRI), with all sets having high specificity. • Non-contrast and hepatobiliary phase AMRI can be performed in less than 14 min (including set-up time), while dynamic AMRI can be performed in less than 17 min. • All AMRI sets were cost-effective for HCC screening in at-risk population in comparison with ultrasound

    A High Statistics Search for Ultra-High Energy Gamma-Ray Emission from Cygnus X-3 and Hercules X-1

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    We have carried out a high statistics (2 Billion events) search for ultra-high energy gamma-ray emission from the X-ray binary sources Cygnus X-3 and Hercules X-1. Using data taken with the CASA-MIA detector over a five year period (1990-1995), we find no evidence for steady emission from either source at energies above 115 TeV. The derived upper limits on such emission are more than two orders of magnitude lower than earlier claimed detections. We also find no evidence for neutral particle or gamma-ray emission from either source on time scales of one day and 0.5 hr. For Cygnus X-3, there is no evidence for emission correlated with the 4.8 hr X-ray periodicity or with the occurrence of large radio flares. Unless one postulates that these sources were very active earlier and are now dormant, the limits presented here put into question the earlier results, and highlight the difficulties that possible future experiments will have in detecting gamma-ray signals at ultra-high energies.Comment: 26 LaTeX pages, 16 PostScript figures, uses psfig.sty to be published in Physical Review
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