Ectrin Ear Tags for Horn Fly Control on Range Beef Cattle

Ectrin ear tags are insecticide-impregnated with the active ingredient fenvalerate (8%). They are approved for use on lactating dairy cattle, beef cattle and calves. Each time an animal turns on tosses its head, a layer of Ectrin is rubbed or falls off onto the animal. As one insecticide layter is rubbed off, another forms. This action continues for the life of the tag. Advantages to this type of horn fly control are tagging is quick and easy using the All-Flex specially designed pliers, dampness or rain has little effect on efficacy, and the fly control reservoir is carried and used by each treated animal. A random sample of 10 animals from each herd was counted using binoculars and looking out of a pickup window. Results are presented as an average number of horn flies/side of these 10 animals. An equal number of untreated or control animals was counted from a herd near the treated herd at nearly the same time. Problems of last tags or infected ears due to the tags were minimal

Horn Fly Control on Range Beef Cattle

Over eleven hundred range cattle were treated with insecticide-impregnated ear tags and observed for horn fly control. Tagging rates compared were herds with one or two tags on each cow, two tags on part of the cows, one tag on half the cows, one tag on each calf (none on the cows) and fenvalerate versus permethrin as the insecticide in the tags. Results from all herds studied showed reductions of 90 to 100% for horn flues after 60 days of treatment for as long as 125 days

Evaluation of One or Two Lutalyse Injections for Estrous Synchronization in Beef Cattle

Researchers have been attempting to control estrous cycles in animals for the last 50 years. For the past several years, there has been considerable interest in the use of Lutalyse for estrous synchronization in beef cattle. For synchronization and artificial insemination to be successful, quality management and nutrition programs must be utilized. Some individual reports have indicated low reproductive performance can be accounted for by noncycling cows, poor management and semen handling techniques efficiency. This study includes data from the 1980, 1981 and 1982 breeding seasons using Lutalyse to synchronize estrous in beef cattle. The purpose of this research was to evaluate the effectiveness of Lutalyse on beef cattle using a single Lutalyse injection compared to two injections given 11 days apart

Advances in three-dimensional geoelectric forward solver techniques

Modern geoelectrical data acquisition systems allow large amounts of data to be collected in a short time. Inversions of such data sets require powerful forward solvers for predicting the electrical potentials. State-of-the-art solvers are typically based on finite elements. Recent developments in numerical mathematics led to direct matrix solvers that allow the equation systems arising from such finite element problems to be solved very efficiently. They are particularly useful for 3-D geoelectrical problems, where many electrodes are involved. Although modern direct matrix solvers include optimized memory saving strategies, their application to realistic, large-scale 3-D problems is still somewhat limited. Therefore, we present two novel techniques that allow the number of gridpoints to be reduced considerably, while maintaining a high solution accuracy. In the areas surrounding an electrode array we attach infinite elements that continue the electrical potentials to infinity. This does not only reduce the number of gridpoints, but also avoids the artificial Dirichlet or mixed boundary conditions that are well known to be the cause of numerical inaccuracies. Our second development concerns the singularity removal in the presence of significant surface topography. We employ a fast multipole boundary element method for computing the singular potentials. This renders unnecessary mesh refinements near the electrodes, which results in substantial savings of gridpoints of up to more than 50 per cent. By means of extensive numerical tests we demonstrate that combined application of infinite elements and singularity removal allows the number of gridpoints to be reduced by a factor of ≈6-10 compared with traditional finite element methods. This will be key for applying finite elements and direct matrix solver techniques to realistic 3-D inversion problem

Did Cosmology Trigger the Origin of the Solar System?

It is a matter of curious coincidence that the Solar System formed 4.6 billion years ago around the same epoch that the Friedmann-Lemaitre (FL) universe became -dominated or dark-energy-dominated, where is the cosmological constant. This observation was made in the context of known gravitational anomalies that affect spacecraft orbits during planetary flyby's and the Pioneer anomaly, both possibly having connections with cosmology. In addition, it has been known for some time that the Universe is not only expanding but accelerating as well. Hence one must add the onset of cosmological acceleration in the FL universe as having a possible influence on the origin of the Solar System. These connections will now be examined in greater detail

Mating and Management Systems for Commerical Beef Production

Recently there has been increased utilization of exotic cattle to increase production in beef herds. Larger calves at weaning and slaughter have resulted due to increased mothering ability and frame size. Hereford-Angus cows have been used extensively in South Dakota and have performed well under local conditions. This study was designed to compare reproductive performance and calf production of S x A and H x A crossbred cows under range conditions. Feedlot performance and carcass beef production have also been evaluated

3-D electrical resistivity tomography using adaptive wavelet parameter grids

We present a novel adaptive model parametrization strategy for the 3-D electrical resistivity tomography problem and demonstrate its capabilities with a series of numerical examples. In contrast to traditional parametrization schemes, which are based on fixed disjoint blocks, we discretize the subsurface in terms of Haar wavelets and adaptively adjust the parametrization as the iterative inversion proceeds. This results in a favourable balance of cell sizes and parameter reliability, that is, in regions where the data constrain the subsurface properties well, our parametrization strategy leads to a fine grid, whereas poorly resolved areas are represented only by a few large blocks. This is documented with eigenvalue analyses and by computing model resolution matrices. During the initial iteration steps, only a few model parameters are involved, which reduces the risk that the regularization dominates the inversion. The algorithm also automatically accounts for non-linear effects caused by pronounced conductivity contrasts. Inside conductive features a finer grid is generated than inside more resistive structures. The automated parameter adaptation is computationally efficient, because the coarsening and refinement subroutines have a nearly linear numerical complexity with respect to the number of model parameters. Because our approach is not tightly coupled to electrical resistivity tomography, it should be straightforward to adapt it to other data type

Quasi-normal modes of AdS black holes : A superpotential approach

A novel method, based on superpotentials is proposed for obtaining the quasi-normal modes of anti-de Sitter black holes. This is inspired by the case of the three-dimensional BTZ black hole, where the quasi-normal modes can be obtained exactly and are proportional to the surface gravity. Using this approach, the quasi-normal modes of the five dimensional Schwarzschild anti-deSitter black hole are computed numerically. The modes again seem to be proportional to the surface gravity for very small and very large black holes. They reflect the well-known instability of small black holes in anti-deSitter space.Comment: LaTeX, 17 pages, 5 eps figures, 1 eepic figure, minor typos correcte

Supply chain finance: optimal introduction and adoption decisions

Supply chain finance (SCF) can improve supply chain performance by facilitating longer payment terms for buyers and better access to financing for suppliers. In spite of these clear benefits, there is empirical evidence for some hesitation and resistance to SCF adoption, manifesting in an often substantial time lag between a buyer's introduction of SCF and its adoption by all targeted suppliers. Observed adoption processes often resemble the s-shaped Bass-curve suggesting that successful early adoptions support adoption decisions by other suppliers. Based on these observations, we consider supplier SCF adoption decisions within a diffusion model, to obtain insights regarding a buyer's optimal SCF introduction decisions in terms of timing and payment terms. We find that initial payment terms and procurement volume strongly affect the optimal timing of SCF introduction and optimal payment term extensions. The degree to which the buyer can influence suppliers in their adoption decisions affects the optimal introduction timing, but not optimal payment terms. Interestingly, our results suggest that, in spite of the clear benefits, many buyers might be well-advised to postpone their SCF implementations

Fate of the Universe, Age of the Universe, Dark Matter, and the Decaying Vacuum Energy

It is shown that in the cosmological models based on a vacuum energy decaying as a^{-2}, where a is the scale factor of the universe, the fate of the universe in regard to whether it will collapse in future or expand forever is determined not by the curvature constant k but by an effective curvature constant k_{eff}. It is argued that a closed universe with k=1 may expand forever, in other words simulate the expansion dynamics of a flat or an open universe because of the possibility that k_{eff}=0 or -1, respectively. Two such models, in one of which the vacuum does not interact with matter and in another of which it does, are studied. It is shown that the vacuum equation of state p_{vac}= -\rho_{vac} may be realized in a decaying vacuum cosmology provided the vacuum interacts wuth matter. The optical depths for gravitational lensing as a function of the matter density and other parameters in the models are calculated at a source redshift of 2. The age of the universe is discussed and shown to be compatible with the new Hipparcos lower limit of 11Gyr. The possibility that a time-varying vacuum energy may serve as dark matter is suggested.Comment: AAS LaTex, 29 pages, published in the Astrophysical Journal, 520, 45, 199