3,583 research outputs found
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
Spatial and statistical variability of soil properties for fields in BMPs in the Steppler sub-watershed, South Tobacco Creek Watershed, research design and preliminary results
Non-Peer Reviewe
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
Le récepteur en immunologie, polysémie-polyphonie historique
L'immunologie est particulièrement riche en expressions métaphoriques qui fournissent d'utiles indicateurs de ses péripéties historiques. L'univers sémantique de ces métaphores déborde les limites du langage scientifique et la polysémie de certains termes-clé scientifiques aide à comprendre leur impact sur l'imagination des chercheurs. Cet article retrace plus particulièrement l'histoire du terme récepteur, sans cesse réemployé depuis le début du XXe siècle et qui assure des fonctions épistémologiques multiples, parmi lesquelles la garantie de la continuité historique en immunologie et le renforcement de l'unité de la disciplin
Intelligent GIS: Automatic generation of qualitative spatial information
This paper reports on an extension to Geographic Information Systems (GIS) that can intelligently analyse and record qualitative information of the surrounding area when adding a feature to a map. This recorded qualitative spatial information can be utilised to perform queries such as path generation using landmarks. Although, there is a lot of research on qualitative spatial reasoning, none of the currently available GIS do actually incorporate this kind of functionality. There have been systems developed that do have functions for adding new features, or generating paths; however they do not generally analyse and record, or use, qualitative information. We have implemented a prototype illustrating our approach. © Springer-Verlag Berlin Heidelberg 2006
High energy gamma-ray constraints on decaying Dark Matter
New bounds on decaying Dark Matter are derived from the gamma-ray
measurements of (i) the isotropic residual (extragalactic) background by Fermi
and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are
among the most stringent constraints currently available, for a large range of
dark matter masses and a variety of decay modes, excluding half-lives up to
about 10^26 to few 10^27 seconds. In particular, they rule out the
interpretation in terms of decaying dark matter of the e+/- spectral features
in PAMELA, Fermi and H.E.S.S., unless very conservative choices are adopted. We
also discuss future prospects for CTA bounds from Fornax which, contrary to the
present H.E.S.S. constraints of (ii), may allow for an interesting improvement
and may become better than those from the current or future extragalactic Fermi
data.Comment: In Proceedings of the 33rd International Cosmic Ray Conference
(ICRC2013), ID622, Rio de Janeiro (Brazil
5-Hydroxymethylcytosine Loss in Conjunctival Melanoma.
Conjunctival and cutaneous melanoma partially share similar clinical and molecular backgrounds. As 5-hydroxymethylcytosine (5-hmC) loss has been demonstrated in cutaneous melanoma, we decided to assess if similar changes were occurring in conjunctival melanoma.
5-methylcytosine (5-mC), 5-hmC and TET2 were respectively identified by immunohistochemistry and RNA ISH in 40 conjunctival nevi and 37 conjunctival melanomas. Clinicopathological correlations were established.
5-mC, TET2 and 5-hmC were respectively identified in 67.5%, 95% and 100% of conjunctival nevi and in 81.1%, 35.1% and 54% of conjunctival melanomas. A significant 5-hmC and TET2 loss was identified in conjunctival melanoma comparing to nevus, as well as a significant correlation between TET2 and 5-hmC expression. In the melanomas, 5-hmC expression was only significantly associated with local lymphatic invasion, but not with other clinicopathological parameters. There was a correlation between TET2 expression and the localization of the tumors. 5-mC expression was not associated with any clinicopathological parameters.
We identified a significant 5-hmC loss in conjunctival melanoma similar to cutaneous melanoma. This loss may possibly be attributed to TET2 loss or IDH1 mutations. 5-hmC loss in conjunctival melanoma may help in the differential diagnosis between atypical conjunctival nevus and conjunctival melanoma
Flow dynamics and magnetic induction in the von-Karman plasma experiment
The von-Karman plasma experiment is a novel versatile experimental device
designed to explore the dynamics of basic magnetic induction processes and the
dynamics of flows driven in weakly magnetized plasmas. A high-density plasma
column (10^16 - 10^19 particles.m^-3) is created by two radio-frequency plasma
sources located at each end of a 1 m long linear device. Flows are driven
through JxB azimuthal torques created from independently controlled emissive
cathodes. The device has been designed such that magnetic induction processes
and turbulent plasma dynamics can be studied from a variety of time-averaged
axisymmetric flows in a cylinder. MHD simulations implementing
volume-penalization support the experimental development to design the most
efficient flow-driving schemes and understand the flow dynamics. Preliminary
experimental results show that a rotating motion of up to nearly 1 km/s is
controlled by the JxB azimuthal torque
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