The impact of seeding date on the yield and quality of oats

Non-Peer ReviewedMost of the research conducted on the optimum seeding date of oats has been done outside of western Canada. The objective of this research is measure the effect of planting dates and cultivars on the yield and quality of oats. Four seeding dates, early May, Mid May, early June, and mid June and four cultivars, AC Medallion, AC Juniper, CDC Boyer and CDC Pacer were used. Delayed seeding resulted in reduced yield and quality of oats. Seeding dates had a larger effect on yield and quality than cultivars except when a high level of crown rust was present in the field. Early and mid May planting dates tend to provide farmers with the least amount of risk when growing oats

High temperature electrolysis, Brayton power cycle and methanol production

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.This paper presents heat exchanger technology that is the key technology in three processes i.e. hydrogen and oxygen production using high temperature steam electrolysis; Brayton power cycle where sCO2 is recycled to the combustor in aim to reduce high temperature achieved after natural gas is combusted in oxygen and methanol production. These processes are combined into one process that enables methanol and electricity production with 100% carbon capture. Industrial hydrogen has been used in many different applications e.g. oil refineries, ammonia and methanol production with demand that has been increasing continuously and expect to rise in days to come. To date, Steam Methane Reforming (SMR) process where methane (natural gas) reacts with steam at high temperature in an endothermic reaction has been adopted as the conventional way to produce industrial hydrogen. However, there are other processes developed to produce hydrogen with electrolysis of steam being one of them. Steam electrolysis includes few different cell types with Solid Oxide Electrolysis Cell (SOEC) that operates at high temperatures being considered in this paper. It needs to be noted that hydrogen produced by steam electrolysis is of highest purity. As steam electrolysis requires electricity which can be provided by either renewable or non-renewable energies, this paper is considering electricity provided by renewable energies (wind, solar or hydro) and electricity produced by Brayton power cycle, so hydrogen is produced without Green House Gas (GHG) emission. To reduce electricity requirement for steam electrolysis diffusion bonded heat exchangers are employed to use heat from turbine exhaust gas and heat realized during hydrogenation of CO2 in methanol production.dc201

Inelastic Neutron Scattering from the Spin Ladder Compound (VO)2P2O7

We present results from an inelastic neutron scattering experiment on the candidate Heisenberg spin ladder vanadyl pyrophosphate, (VO)2P2O7. We find evidence for a spin-wave excitation gap of $E_{gap} = 3.7\pm 0.2$ meV, at a band minimum near $Q=0.8 A^{-1}$. This is consistent with expectations for triplet spin waves in (VO)2P2O7 in the spin-ladder model, and is to our knowledge the first confirmation in nature of a Heisenberg antiferromagnetic spin ladder.Comment: 11 pages and 2 figures (available as hard copy or postscript files from the authors, send request to [email protected] or [email protected]), TEX using jnl, reforder and eqnorder, ORNL-CCIP-94-05 / RAL-94-04

Dynamical Properties of Two Coupled Hubbard Chains at Half-filling

Using grand canonical Quantum Monte Carlo (QMC) simulations combined with Maximum Entropy analytic continuation, as well as analytical methods, we examine the one- and two-particle dynamical properties of the Hubbard model on two coupled chains at half-filling. The one-particle spectral weight function, $A({\bf k},\omega)$, undergoes a qualitative change with interchain hopping $t_\perp$ associated with a transition from a four-band insulator to a two-band insulator. A simple analytical model based on the propagation of exact rung singlet states gives a good description of the features at large $t_\perp$. For smaller $t_\perp$, $A({\bf k}, \omega)$ is similar to that of the one-dimensional model, with a coherent band of width the effective antiferromagnetic exchange $J$ reasonably well-described by renormalized spin-wave theory. The coherent band rides on a broad background of width several times the parallel hopping integral $t$, an incoherent structure similar to that found in calculations on both the one- and two-dimensional models. We also present QMC results for the two-particle spin and charge excitation spectra, and relate their behavior to the rung singlet picture for large $t_\perp$ and to the results of spin-wave theory for small $t_\perp$.Comment: 9 pages + 10 postscript figures, submitted to Phys.Rev.B, revised version with isotropic t_perp=t data include

The ground state of the two-leg Hubbard ladder: a density--matrix renormalization group study

We present density-matrix renormalization group results for the ground state properties of two-leg Hubbard ladders. The half-filled Hubbard ladder is an insulating spin-gapped system, exhibiting a crossover from a spin-liquid to a band-insulator as a function of the interchain hopping matrix element. When the system is doped, there is a parameter range in which the spin gap remains. In this phase, the doped holes form singlet pairs and the pair-field and the "$4 k_F$" density correlations associated with pair density fluctuations decay as power laws, while the "$2 k_F$" charge density wave correlations decay exponentially. We discuss the behavior of the exponents of the pairing and density correlations within this spin gapped phase. Additional one-band Luttinger liquid phases which occur in the large interband hopping regime are also discussed.Comment: 14 pages, 18 figures, uses Revtex with epsfig to include the figure

Measuring proper motions of isolated neutron stars with Chandra

The excellent spatial resolution of the Chandra observatory offers the unprecedented possibility to measure proper motions at X-ray wavelength with relatively high accuracy using as reference the background of extragalactic or remote galactic X-ray sources. We took advantage of this capability to constrain the proper motion of RX J0806.4-4123 and RX J0420.0-5022, two X-ray bright and radio quiet isolated neutron stars (INSs) discovered by ROSAT and lacking an optical counterpart. In this paper, we present results from a preliminary analysis from which we derive 2 sigma upper limits of 76 mas/yr and 138 mas/yr on the proper motions of RX J0806.4-4123 and RX J0420.0-5022 respectively. We use these values together with those of other ROSAT discovered INSs to constrain the origin, distance and evolutionary status of this particular group of objects. We find that the tangential velocities of radio quiet ROSAT neutron stars are probably consistent with those of 'normal' pulsars. Their distribution on the sky and, for those having accurate proper motion vectors, their possible birth places, all point to a local population, probably created in the part of the Gould Belt nearest to the earth.Comment: 8 pages, 3 figures, to appear in Astrophysics and Space Science, in the proceedings of "Isolated Neutron Stars: from the Interior to the Surface", edited by D. Page, R. Turolla and S. Zan

Parasitic helminth infections and the control of human allergic and autoimmune disorders

The profile of global health today presents a striking reciprocal distribution between parasitic diseases in many of the world’s lower-income countries, and ever-increasing levels of inflammatory disorders such as allergy, autoimmunity and inflammatory bowel diseases in the more affluent societies. Attention is particularly focused on helminth worm parasites, which are associated with protection from allergy and inflammation in both epidemiological and laboratory settings. One mechanistic explanation of this is that helminths drive the regulatory arm of the immune system, abrogating the ability of the host to expel the parasites, while also dampening reactivity to many “bystander” specificities. Interest has therefore heightened into whether helminth parasites, or their products, hold therapeutic potential for immunological disorders of the developed world. In this narrative review, progress across a range of trials is discussed, together with prospects for isolating individual molecular mediators from helminths that may offer defined new therapies for inflammatory conditions

Dimensional Crossover of Localisation and Delocalisation in a Quantum Hall Bar

The 2-- to 1--dimensional crossover of the localisation length of electrons confined to a disordered quantum wire of finite width $L_y$ is studied in a model of electrons moving in the potential of uncorrelated impurities. An analytical formula for the localisation length is derived, describing the dimensional crossover as function of width $L_y$, conductance $g$ and perpendicular magnetic field $B$ . On the basis of these results, the scaling analysis of the quantum Hall effect in high Landau levels, and the delocalisation transition in a quantum Hall wire are reconsidered.Comment: 12 pages, 7 figure

Chronotype: Implications for Epidemiologic Studies on Chrono-Nutrition and Cardiometabolic Health

Chrono-nutrition is an emerging research field in nutritional epidemiology that encompasses 3 dimensions of eating behavior: timing, frequency, and regularity. To date, few studies have investigated how an individual’s circadian typology, i.e., one’s chronotype, affects the association between chrono-nutrition and cardiometabolic health. This review sets the directions for future research by providing a narrative overview of recent epidemiologic research on chronotype, its determinants, and its association with dietary intake and cardiometabolic health. Limited research was found on the association between chronotype and dietary intake in infants, children, and older adults. Moreover, most of the evidence in adolescents and adults was restricted to cross-sectional surveys with few longitudinal cohorts simultaneously collecting data on chronotype and dietary intake. There was a gap in the research concerning the association between chronotype and the 3 dimensions of chrono-nutrition. Whether chronotype modifies the association between diet and cardiometabolic health outcomes remains to be elucidated. In conclusion, further research is required to understand the interplay between chronotype, chrono-nutrition, and cardiometabolic health outcomes

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

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