1,055 research outputs found
ECONOMIC BENEFITS OF WEATHER PROTECTION FOR LARGE ROUND BALES
. 1986. Economic benefits of weather protection for large round bales. Can. An economic evaluation ofthe storage losses ofvarious haying systems isreported. This information was necessary to augment a study of the effect of storage characteristicson round bale quality in which round bales from two different round baler types (fixed and variable bale chamber) were stored in five different manners. In addition, the costs of harvesting and storing hay by several methods were evaluated. These costs were translated into costs per "useable" tonneof hay. Values of spoiledhay were compared with the values of weather protection for round bales. The values ofhay spoilage indifferent types of storage were combined with detailed costs of growing, harvesting and storing hay and compared. Economic comparison with traditional rectangular bale harvesting methods is also included. It was found that round bale harvesting was the least expensive method at all volumes. Round bale harvesting with inside storage or plastic wrap protection provided a higher value than outside storage of round bales because of the increased spoilage when not protected. The cost of inside storage was equal to 14% spoilage of round bales
New methods for unmixing sediment grain size data
Grain size distribution (GSD) data are widely used in Earth sciences and although large data sets are regularly generated, detailed numerical analyses are not routine. Unmixing GSDs into components can help understand sediment provenance and depositional regimes/processes. End-member analysis (EMA), which fits one set of end-members to a given data set, is a powerful way to unmix GSDs into geologically meaningful parts. EMA estimates end-members based on covariability within a data set and can be considered as a nonparametric approach. Available EMA algorithms, however, either produce suboptimal solutions or are time consuming. We introduce unmixing algorithms inspired by hyperspectral image analysis that can be applied to GSD data and which provide an improvement over current techniques. Nonparametric EMA is often unable to identify unimodal grain size subpopulations that correspond to single sediment sources. An alternative approach is single-specimen unmixing (SSU), which unmixes individual GSDs into unimodal parametric distributions (e.g., lognormal). We demonstrate that the inherent nonuniqueness of SSU solutions renders this approach unviable for estimating underlying mixing processes. To overcome this, we develop a new algorithm to perform parametric EMA, whereby an entire data set can be unmixed into unimodal parametric end-members (e.g., Weibull distributions). This makes it easier to identify individual grain size subpopulations in highly mixed data sets. To aid investigators in applying these methods, all of the new algorithms are available in AnalySize, which is GUI software for processing and unmixing grain size data
Fermi surface and order parameter driven vortex lattice structure transitions in twin-free YBa2Cu3O7
We report on small-angle neutron scattering studies of the intrinsic vortex
lattice (VL) structure in detwinned YBa2Cu3O7 at 2 K, and in fields up to 10.8
T. Because of the suppressed pinning to twin-domain boundaries, a new distorted
hexagonal VL structure phase is stabilized at intermediate fields. It is
separated from a low-field hexagonal phase of different orientation and
distortion by a first-order transition at 2.0(2) T that is probably driven by
Fermi surface effects. We argue that another first-order transition at 6.7(2)
T, into a rhombic structure with a distortion of opposite sign, marks a
crossover from a regime where Fermi surface anisotropy is dominant, to one
where the VL structure and distortion is controlled by the order-parameter
anisotropy.Comment: 4 pages, 3 figures (2 color), minor change
Stress appraisal, coping, and work engagement among police recruits: an exploratory study.
This study investigated the influence of stress appraisal and coping on work engagement levels (Absorption, Vigour, and Dedication) of police recruits. Participants were 387 men, ages 20 to 33 yr. (M = 24.1, SD = 2.4), in their last month of academy training before becoming police officers. Partially in support of predictions, work engagement was associated with Stressor control perceived, but not Stress intensity experienced over a self-selected stressor. Although the three dimensions of work engagement were explained by Stressor control and coping, Absorption was the dimension better explained by these variables. Police recruits reporting higher Absorption, Vigour, and Dedication reported using more Active coping and less Behavioural disengagement. Results showed that stress appraisal and coping are important variables influencing work engagement among police recruits. Findings suggested that future applied interventions fostering work engagement among police recruits should reinforce perceptions of control over a stressor as well as Active coping strategies
The pairing state in KFe2As2 studied by measurements of the magnetic vortex lattice
Understanding the mechanism and symmetry of electron pairing in iron-based
superconductors represents an important challenge in condensed matter physics
[1-3]. The observation of magnetic flux lines - "vortices" - in a
superconductor can contribute to this issue, because the spatial variation of
magnetic field reflects the pairing. Unlike many other iron pnictides, our
KFe2As2 crystals have very weak vortex pinning, allowing
small-angle-neutron-scattering (SANS) observations of the intrinsic vortex
lattice (VL). We observe nearly isotropic hexagonal packing of vortices,
without VL-symmetry transitions up to high fields along the fourfold c-axis of
the crystals, indicating rather small anisotropy of the superconducting
properties around this axis. This rules out gap nodes parallel to the c-axis,
and thus d-wave and also anisotropic s-wave pairing [2, 3]. The strong
temperature-dependence of the intensity down to T<<Tc indicates either widely
different full gaps on different Fermi surface sheets, or nodal lines
perpendicular to the axis.Comment: 13 pages, 3 figure
Operator mixing and three-point functions in N=4 SYM
We study the three-point functions between two BPS and one non-BPS local
gauge invariant operators in N=4 Super Yang-Mills theory. In particular we
show, in explicit 1-loop examples, that the operator mixing discussed in
arXiv:0810.0499 plays an important role in the computations of the correlators
and is necessary to cancel contributions that would violate the constraints
following from the superconformal and the bonus U(1)_Y symmetries. We analyse
the same type of correlators also at strong coupling by using the BMN limit of
the AdS_5xS^5 string theory. Again the mixing between states with different
types of impurities is crucial to ensure the cancellation of various amplitudes
that would violate the constraints mentioned above. However, on the string
side, we also find some examples of interactions between one non-BPS and two
BPS states that do not satisfy expectations based on the superconformal and the
bonus U(1)_Y symmetries.Comment: 28 pages, 5 figure
Differential equations for multi-loop integrals and two-dimensional kinematics
In this paper we consider multi-loop integrals appearing in MHV scattering
amplitudes of planar N=4 SYM. Through particular differential operators which
reduce the loop order by one, we present explicit equations for the two-loop
eight-point finite diagrams which relate them to massive hexagons. After the
reduction to two-dimensional kinematics, we solve them using symbol technology.
The terms invisible to the symbols are found through boundary conditions coming
from double soft limits. These equations are valid at all-loop order for double
pentaladders and allow to solve iteratively loop integrals given lower-loop
information. Comments are made about multi-leg and multi-loop integrals which
can appear in this special kinematics. The main motivation of this
investigation is to get a deeper understanding of these tools in this
configuration, as well as for their application in general four-dimensional
kinematics and to less supersymmetric theories.Comment: 25 pages, 7 figure
Positive Energy Unitary Irreducible Representations of the Superalgebras osp(1|2n,R)
We give the classification of the positive energy (lowest weight) unitary
irreducible representations of the superalgebras osp(1|2n,R).Comment: 20 pages, LATEX2e (revtex4,amsmath,amssymb), Plenary talk by VKD at X
International Conference on Symmetry Methods in Physics, Yerevan,
13-21.8.2003; added acknowledgements; corrected misprint
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