Nitrous oxide emissions from soil profiles seeded with pulse crops

Non-Peer ReviewedInoculation of legumes with Rhizobium spp. is a common worldwide agricultural practice that is used to increase crop yield and to improve soil fertility without adding nitrogen (N) fertilizers. There is concern that N2 fixation by legumes enhances emissions of nitrous oxide (N2O) – a powerful greenhouse gas (GHG). The objectives of this experiment were: 1) to measure N2O emissions from soil profiles under inoculated and non-inoculated pulse crops; 2) to investigate the relationship between N2O emissions and N2 fixation by pulse crops. The experiment was carried out in the Phytotron of the University of Saskatchewan with soil flats seeded with inoculated and non-inoculated lentils and peas and fertilized spring wheat. N2O emissions from soil profiles were measured using Profile Gas Samplers (PGS), and were analyzed with a GC. Results indicated that inoculated lentils and peas did not substantially increase N2O emissions, and N2O emissions may not be associated with N2 fixation under the conditions in this experiment

Investigation of shell and axisymmetric shell structures

The author is with the Central Electricity Research Laboratories (C. E. R. L. ) Leatherhead, of the Central Electricity Generating Board (C. E. G. B. ) In October 1974 he was registered with The City University to undertake research leading eventually to the Degree of Doctor of Philosophy. The author's research was carried out during the registration period and has also been reported in the following C. E. G. B. Publications: - 1. Nelson, R. L., VACTIL: a program to analyse the natural frequencies and mode shapes of cooling towers whilst explicitly including the effects of leg supports and foundation elasticity, C. E. G. B. pub. No. RD/L/P 10/76. 2. Nelson, R. L., and Hellewell, J. S., * Vibration tests on a 1/250th scale model of Didcot cooling tower, C. E. G. B. pub. No. RD/L/N 112/76. (The first author was a supervisor to the second author who was a pre-university vacation trainee. The first author was a co-worker during the project; also he commissioned the apparatus, planned the experiment and wrote the paper. ) 3. Nelson, R. L1., Stress matrix for a doubly curved shell finite element, C. E. G. B. pub. No. RD/L/N 113/76 4. Nelson, R. L1., A new algorithm to program the element matrices of doubly curved shell finite elements, C. E. G. B. pub. No. RD/L/N 139/77 5. Nelson, R. Ll., Free vibration analysis of cooling towers with leg-supports by a finite element method, C. E. C. B. pub. No. RD/L/R 1935 6. Nelson, R. Ll., Proposals for improved doubly curved shell finite elements, C. E. G. B. pub. No. RD/L/N 140/77 7. Nelson, R. L1., RESAP: a program to calculate the resonant stresses, frequencies and mode shapes of axisymmetric structures, C. E. G. B. pub. No. RD/L/P 9/77. 8. Nelson, R. L1., VACTILo2: a program to calculate the frequencies, mode shapes and stresses of shell structures, C. E. G. B. pub. No. RD/L/P /77. 9. Nelson, R. L1., Calculation of stresses mode shapes and frequencies of shell structures using doubly-curved finite elements, C. E. G. B. pub. No. RD/L/N _187/77. No part of this thesis, in whole or in part, has been submitted elsewhere for the award of a higher degree or qualification. Unless otherwise stated the work is the candidates own

Balancing the phosphorus budget of a swine farm: A case study

Trends in animal production have moved the industry toward large confined animal feeding operations (CAFOs). These CAFOs concentrate large amounts of manure-based nutrients in relatively small areas, which increases the risk of nutrient loss to the surrounding environment. In response to water quality concerns, P-based manure application regulations are becoming more common. Mr. Pritchard is the owner and operator of two 4500-head swine (Sus scrofa) farms located in an area of intensive animal production in North Carolina. He has noticed an increasing trend in the soil P concentrations in his manure application fields and realizes that he does not have enough land to apply his anaerobically treated liquid swine manure based on crop P uptake. Mr. Pritchard is now faced with the dilemma of what to do to slow down the P accumulation in his soil. This case constructs a P budget for Mr. Pritchard's farm to examine ways of balancing on-farm nutrients. Students are encouraged to explore solutions related to animal nutrition, crop production, water quality, soil chemistry, and manure management. Furthermore, students should evaluate the appropriate role of government and industry in assisting Mr. Pritchard to protect the environment while remaining a profitable swine producer

Field-scale evaluation of phosphorus leaching in acid sandy soils receiving swine waste

Accurate descriptions of P leaching are important because excess P applied to soils can enter surface water via leaching and subsurface transport, thereby negatively impacting water quality. The objectives of this study were to monitor P leaching in soils with a long-term history of waste application, relate soil solution P concentrations to soil P status, and quantify P leaching losses. Soil solution was monitored for 20 mo with samplers installed at 45-, 90-, and 135-cm depths in two pits (1 X 3 X L5 m) in Autryville (loamy, siliceous, thermic Arenic Paleudults) and Blanton (loamy, siliceous, semiactive, thermic Grossarenic Paleudults) soils located in a grazed pasture in Sampson County, NC, which had received swine waste for >20 yr. Maximum soil solution P concentrations at 45 cm exceeded 18 mg L' in both soils. Soil solution P concentrations at 90 cm in the Blanton soil were similar to that at 45 cm indicating low P sorption. Soil solution P concentrations at 90 cm in the Autryville soil averaged 0.05 mg L-' compared to 10 mg L' at 45 cm. A split-line model related soil solution P concentration to the degree of phosphorus saturation (DPS), identifying a change point at 45% DPS. Phosphorus movement past 45 cm equaled or exceeded surplus P additions for both soils. Longterm waste applications resulted in DPS > 90%, high soil solution P concentrations, and substantial vertical P movement. Phosphorus leaching should be considered when assessing long-term risk of P loss from waste-amended soils

Associations between blood sex steroid concentrations and risk of major adverse cardiovascular events in healthy older women in Australia: a prospective cohort substudy of the ASPREE trial

Background: Blood testosterone concentrations in women decline during the reproductive years and reach a nadir in the seventh decade, after which concentrations increase and are restored to those of reproductive-aged women early in the eighth decade. We aimed to establish the association between the concentration of testosterone in the blood and risk of major adverse cardiovascular events (MACE) and all-cause mortality in healthy older women. Methods: SHOW was a prospective cohort substudy of the longitudinal randomised ASPREE trial. Eligible participants were women aged at least 70 years from Australia with unimpaired cognition, no previous MACE, and a life expectancy of at least 5 years. Participants who were receiving hormonal or steroid therapy were ineligible for inclusion. We measured serum concentrations of sex steroids with liquid chromatography–tandem mass spectrometry and of SHBG with immunoassay. We compared lower concentrations of sex hormones with higher concentrations using four quartiles. Primary endpoints were risk of MACE and all-cause mortality, the associations of which with sex steroid concentrations were assessed using Cox proportional hazards regression that included age, body-mass index, smoking status, alcohol consumption, diabetes, hypertension, dyslipidaemia, impaired renal function, and treatment allocation in the ASPREE trial (aspirin vs placebo). ASPREE is registered with ClinicalTrials.gov, NCT01038583. Findings: Of the 9180 women recruited to the ASPREE trial between March 10, 2010, and Dec 31 2014, 6358 participants provided sufficient biobank samples at baseline and 5535 were included in the final analysis. Median age at entry was 74·0 years (IQR 71·7–77·7). During a median 4·4 years of follow-up (24 553 person-years), 144 (2·6%) women had a first MACE (incidence 5·9 per 1000 person-years). During a median 4·6 years of follow-up (3·8–5·6), 200 women died (7·9 per 1000 person-years). In the fully adjusted models, higher concentrations of testosterone were associated with a lower incidence of MACE (quartile 4 vs quartile 1: hazard ratio 0·57 [95% CI 0·36–0·91]; p=0·02), as were higher concentrations of DHEA (quartile 4 vs quartile 1: 0·61 [0·38–0·97]; p=0·04). For oestrone, a lower risk of MACE was seen for concentrations in quartile 2 only, compared with quartile 1 (0·55 [0·33–0·92]; p=0·02). In fully adjusted models, no association was seen between SHBG and MACE, or between any hormone or SHBG and all-cause mortality. Interpretation: Blood concentrations of testosterone and DHEA above the lowest quartile in older women were associated with a reduced risk of a first-ever MACE. Given that the physiological effects of DHEA are mediated through its steroid metabolites, if the current findings were to be replicated, trials investigating testosterone therapy for the primary prevention of ischaemic cardiovascular disease events in older women would be warranted. Funding: The National Health and Medical Research Council of Australia, US National Institute on Aging, the Victorian Cancer Agency, the Commonwealth Scientific and Industrial Research Organisation, and Monash University

Topological Defects, Orientational Order, and Depinning of the Electron Solid in a Random Potential

We report on the results of molecular dynamics simulation (MD) studies of the classical two-dimensional electron crystal in the presence disorder. Our study is motivated by recent experiments on this system in modulation doped semiconductor systems in very strong magnetic fields, where the magnetic length is much smaller than the average interelectron spacing $a_0$, as well as by recent studies of electrons on the surface of helium. We investigate the low temperature state of this system using a simulated annealing method. We find that the low temperature state of the system always has isolated dislocations, even at the weakest disorder levels investigated. We also find evidence for a transition from a hexatic glass to an isotropic glass as the disorder is increased. The former is characterized by quasi-long range orientational order, and the absence of disclination defects in the low temperature state, and the latter by short range orientational order and the presence of these defects. The threshold electric field is also studied as a function of the disorder strength, and is shown to have a characteristic signature of the transition. Finally, the qualitative behavior of the electron flow in the depinned state is shown to change continuously from an elastic flow to a channel-like, plastic flow as the disorder strength is increased.Comment: 31 pages, RevTex 3.0, 15 figures upon request, accepted for publication in Phys. Rev. B., HAF94MD

Analysis of Nematic Liquid Crystals with Disclination Lines

We investigate the structure of nematic liquid crystal thin films described by the Landau--de Gennes tensor-valued order parameter with Dirichlet boundary conditions of nonzero degree. We prove that as the elasticity constant goes to zero a limiting uniaxial texture forms with disclination lines corresponding to a finite number of defects, all of degree 1/2 or all of degree -1/2. We also state a result on the limiting behavior of minimizers of the Chern-Simons-Higgs model without magnetic field that follows from a similar proof.Comment: 40 pages, 1 figur

Edge magnetoplasmons in periodically modulated structures

We present a microscopic treatment of edge magnetoplasmons (EMP's) within the random-phase approximation for strong magnetic fields, low temperatures, and filling factor $\nu =1(2)$, when a weak short-period superlattice potential is imposed along the Hall bar. The modulation potential modifies both the spatial structure and the dispersion relation of the fundamental EMP and leads to the appearance of a novel gapless mode of the fundamental EMP. For sufficiently weak modulation strengths the phase velocity of this novel mode is almost the same as the group velocity of the edge states but it should be quite smaller for stronger modulation. We discuss in detail the spatial structure of the charge density of the renormalized and the novel fundamental EMP's.Comment: 8 pages, 4 figure

Health-Related Quality of Life and All-Cause Mortality among Older Healthy Individuals in Australia and the United States:A Prospective Cohort Study

Published online: 3 January 2021PURPOSE: Previous research has demonstrated that lower health-related quality of life (HRQoL) is associated with higher morbidity and mortality, especially in-patient groups. The association of HRQoL with all-cause mortality in community samples requires further investigation. This study aimed to examine whether HRQoL predicts all-cause mortality in older healthy community-dwelling people from Australia and the United States (U.S.) enrolled in the Aspirin in Reducing Events in the Elderly (ASPREE) trial. We also explored whether this association varies by gender or country. METHOD: A prospective cohort of 19,106 individuals aged 65-98 years, who were without a dementia diagnosis or a known major life-limiting disease, and completed the 12-item short-form-HRQoL at recruitment (2010-2014). They were followed until June 2017. Cox proportional-hazard models were used to determine the association between the physical (PCS) and mental component scores (MCS) of HRQoL and all-cause mortality, adjusting for sociodemographic factors, health-related behaviours and clinical measures. Hazards ratios were estimated for every 10-unit increase in PCS or MCS. RESULTS: There were 1052 deaths over a median 4.7-years (interquartile range 3.6-5.7) of follow-up, with 11.9 events per 1000 person-years. Higher PCS was associated with lower all-cause mortality (HR 0.83, 95% CI 0.77, 0.89) in the entire sample, while higher MCS was associated with lower mortality among U.S. participants only (HR 0.78, 95% CI 0.63, 0.95). Gender differences in the association of either PCS or MCS with mortality were not observed. CONCLUSION: Our large study provides evidence that HRQoL is inversely associated with all-cause mortality among initially healthy older people.Aung Zaw Zaw Phyo, Joanne Ryan, David A. Gonzalez-Chica, Robyn L. Woods, Christopher M. Reid, Mark R. Nelson ... et al

Influencia del manejo del cultivo de maíz sobre el microbioma: implicancias en la pudrición de raíz y tallo

PosterActualmente, una de las principales limitantes para el cultivo de maíz son las enfermedades causadas por hongos. Entre las enfermedades fúngicas reportadas en las últimas campañas se encuentra la pudrición de raíz y tallo (PRT), producida por un complejo de patógenos que habitan en los rastrojos y/o suelo. En los últimos años, esta enfermedad ha incrementado su frecuencia e intensidad, lo cual está asociado a siembras tardías, maíces de segunda y otoños húmedos. Además, el aumento en la densidad de siembra junto con la producción continua del cultivo e inclusión de gramíneas en la secuencia, favorecerían la enfermedad. En este sentido, la intensificación del uso del suelo, implica su progresivo deterioro, generando un desbalance en sus propiedades microbianas, químicas y físicas, lo cual podría explicar el aumento de la incidencia de la enfermedad. Se sabe que algunas prácticas de manejo, como el monocultivo, también tienen efectores estresores sobre el maíz. Por el contrario, la rotación de cultivos, promueve la producción y sanidad de los cultivos principalmente a través de una mejora en las condiciones del suelo (mejor estructura, incremento del contenido de nutrientes, aumento de la biomasa y actividades microbianas, interrupción de los ciclos de los patógenos).Instituto de Patología VegetalFil: Serri, Dannae Lilia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Serri, Dannae Lilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Bernardi Lima, Nelson. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Bernardi Lima, Nelson. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: De Rossi, R.L. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Vargas Gil, Silvina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Vargas Gil, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); Argentin