Economics of mixed farming under rotational grazing with low input system

Non-Peer ReviewedThis study was conducted at the Manitoba Zero Tillage Research Farm (MZTRA) located 17.6 kilometres north of Brandon, Manitoba. The objective was to evaluate new farming systems designed to improve economic return, sequester carbon, and reduce inputs, energy use, and greenhouse gas emissions of mixed production systems. Yield and net revenue varied across MZTRA landscapes due to spatial and temporal variability of soil fertility and biophysical properties. Relative to studies with conservation tillage in the Canadian Prairies, producers can expect to achieve higher crop yields with most crops under zero tillage. Compared to crop yields reported for conventional tillage (CT) in Thin Black soil zone of Saskatchewan, spring wheat was 11 to 32% higher, winter wheat 41 to 66% higher, pea 27% higher, and flax was comparable. There were no significant differences in total input cost among annual crop rotation. Our results indicated that small-scale mixed crop and livestock operations had higher operating costs, the success of which depended on animal and environmental conditions as well as management. Hay and grazing systems also had higher risk. Among annual crops, although net revenue was higher for canola and peas, risk was also higher due to higher net revenue variation for these two crops. The findings showed that the use of zero tillage with low inputs has the potential to save energy use and improve energy use efficiency. The use of zero tillage provided significant energy savings (compared to CT reported by Zentner et al. (2004)) in on-farm use of fuel and in machine operation and manufacture. The ratio of grain, oilseed and pea yield to emission of CO2 (kg yield per kg CO2 emitted) varied considerably between crops. This ratio was similar for winter wheat and spring wheat, but not for canola and flax. Canola ratios were higher than flax (2.03 compare to 1.92 kg of flax). Peas had a higher ratio (8.47 kg), due to low fertilizer rates. Alfalfa had the highest ratio (17.8 kg yield kg CO2, due to low inputs of fertilizer and pesticides. Overall the crops and rotations studied were highly energy efficient and reduced the calculated contribution of GHGs to the environment especially when legume and N-fixing crops were incorporated

Modelling soil dynamics and the effect of nitrogen levels on potato yield function

Non-Peer ReviewedCrop yield is maximized when optimal levels of nutrients, water, and other inputs are available to the crop and the influence of disease and weeds has been minimized. While each crop has differing responses to nutrient availability, modelling soil dynamics and the effect of nitrogen levels on potato yield is very important. The objective of this study was to model several environmental components of potato yield function including soil characteristics and organic matter content, soil nitrogen, temperature component, moisture component, solum and nitrogen mineralization, nitrogen fertilizer, and nitrogen sufficiency. The interaction of these components with moisture availability and nitrogen sufficiency was shown to impact potato yield

Remembering and knowing: using another's subjective report to make inferences about memory strength and subjective experience

The Remember-Know paradigm is commonly used to examine experiential states during recognition. In this paradigm, whether a Know response is defined as a high-confidence state of certainty or a low-confidence state based on familiarity varies across researchers, and differences in definitions and instructions have been shown to influence participants' responding. Using a novel approach, in three internet-based questionnaires participants were placed in the role of 'memory expert' and classified others' justifications of recognition decisions. Results demonstrated that participants reliably differentiated between others' memory experiences--both in terms of confidence and other inherent differences in the justifications. Furthermore, under certain conditions, manipulations of confidence were found to shift how items were assigned to subjective experience categories (Remember, Know, Familiar, and Guess). Findings are discussed in relation to the relationship between subjective experience and confidence, and the separation of Know and Familiar response categories within the Remember-Know paradigm

Cooling Tests of the NectarCAM camera for the Cherenkov Telescope Array

The NectarCAM is a camera proposed for the medium-sized telescopes in the framework of the Cherenkov Telescope Array (CTA), the next-generation observatory for very-high-energy gamma-ray astronomy. The cameras are designed to operate in an open environment and their mechanics must provide protection for all their components under the conditions defined for the CTA observatory. In order to operate in a stable environment and ensure the best physics performance, each NectarCAM will be enclosed in a slightly overpressurized, nearly air-tight, camera body, to prevent dust and water from entering. The total power dissipation will be ~7.7 kW for a 1855-pixel camera. The largest fraction is dissipated by the readout electronics in the modules. We present the design and implementation of the cooling system together with the test bench results obtained on the NectarCAM thermal demonstrator.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Interpretation of 2-probe turbulence measurements in an axisymmetric contraction

Simultaneous measurements of the streamwise and radial velocity components at two points, one on and one off the centerline with variable radial separation, were digitally recorded and processed at several stations along a four to one contraction with controlled upstream turbulence conditions. Various statistical quantities are presented including spectra and coherence functions. The integral L sub ux, L sub um, L sub vx, L sub vm were also estimated and their variation along the contraction is examined

Total Synthesis of Iejimalide A-D and Assessment of the Remarkable Actin-Depolymerizing Capacity of These Polyene Macrolides

A concise and convergent total synthesis of the highly cytotoxic marine natural products iejimalide A−D (1−4) is reported, which relies on an effective ring-closing metathesis (RCM) reaction of a cyclization precursor containing no less than 10 double bonds. Because of the exceptional sensitivity of this polyunsaturated intermediate and its immediate precursors toward acid, base, and even gentle warming, the assembly process hinged upon the judicious choice of protecting groups and the careful optimization of all individual transformations. As a consequence, particularly mild protocols for Stille as well as Suzuki reactions of elaborate coupling partners have been developed that hold considerable promise for applications in other complex settings. Moreover, a series of non-natural “iejimalide-like” compounds has been prepared, differing from the natural lead in the polar head groups linked to the macrolide's N-terminus. With the aid of these compounds it was possible to uncover the hitherto unknown effect of iejimalide and analogues on the actin cytoskeleton. Their capacity to depolymerize this microfilament network rivals that of the latrunculins which constitute the standard in the field. Structural modifications of the peptidic terminus in 2 are thereby well accommodated, without compromising the biological effects. The iejimalides hence constitute an important new class of probe molecules for chemical biology in addition to their role as promising lead structures for the development of novel anticancer agents

Description and validation of an AOT product over land at the 0.6 μm channel of the SEVIRI sensor onboard MSG

The Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard Meteosat Second Generation (MSG) launched in 2003 by EUMETSAT is dedicated to the Nowcasting applications and Numerical Weather Prediction and to the provision of observations for climate monitoring and research. We use the data in visible and near infrared (NIR) channels to derive the aerosol optical thickness (AOT) over land. The algorithm is based on the assumption that the top of the atmosphere (TOA) reflectance increases with the aerosol load. This is a reasonable assumption except in case of absorbing aerosols above bright surfaces. We assume that the minimum in a 14-days time series of the TOA reflectance is, once corrected from gaseous scattering and absorption, representative of the surface reflectance. The AOT and the aerosol model (a set of 5 models is used), are retrieved by matching the simulated TOA reflectance with the TOA reflectances measured by SEVIRI in its visible and NIR spectral bands. <br><br> The high temporal resolution of the data acquisition by SEVIRI allows to retrieve the AOT every 15 min with a spatial resolution of 3 km at sub-satellite point, over the entire SEVIRI disk covering Europe, Africa and part of South America. The resulting AOT, a level 2 product at the native temporal and spatial SEVIRI resolutions, is presented and evaluated in this paper. <br><br> The AOT has been validated using ground based measurements from AErosol RObotic NETwork (AERONET), a sun-photometer network, focusing over Europe for 3 months in 2006. The SEVIRI estimates correlate well with the AERONET measurements, <i>r</i> = 0.64, with a slight overestimate, bias = −0.017. The sources of errors are mainly the cloud contamination and the bad estimation of the surface reflectance. The temporal evolutions exhibited by both datasets show very good agreement which allows to conclude that the AOT Level 2 product from SEVIRI can be used to quantify the aerosol content and to monitor its daily evolution with a high temporal frequency. The comparison with daily maps of Moderate Resolution Imaging Spectroradiometer (MODIS) AOT level 3 product shows qualitative good agreement in the retrieved geographic patterns of AOT. <br><br> Given the high spatial and temporal resolutions obtained with this approach, our results have clear potential for applications ranging from air quality monitoring to climate studies. This paper presents a first evaluation and validation of the derived AOT over Europe in order to document the overall quality of a product that will be made publicly available to the users of the aforementioned research communities