3,610 research outputs found
An Injectable Trace Mineral Supplement in Yearling Bulls Causes a Short-Term Increase in Circulating Trace Mineral Levels But Does Not Improve Sperm Quality
Proper trace mineral supplementation is necessary for reproductive development and function. Supplementation with various trace minerals has been shown to improve overall sperm quality and morphology and increase the percentage of live sperm. When developing beef bulls, it is necessary to meet trace mineral requirements to ensure proper reproductive success. An injectable trace mineral product has been made commercially available for use in cattle as a supplemental form of chelated selenium, copper, zinc, and manganese. Considering the role of trace minerals in bull reproductive function, we posed the question of whether using an injectable trace mineral product beyond dietary supplementation could improve sperm quality and percentage of bulls passing yearling breeding soundness exams. The objectives of our study were to compare serum trace mineral concentrations of bulls before and after administration of an injection of trace minerals or saline and to compare semen trace mineral concentrations after treatment. To determine if an injectable trace mineral product could be of benefit, we compared serum and semen trace mineral concentrations as well as semen quality and percentage passing a yearling breeding soundness examination in treated and untreated bulls
Manoeuvring simulation on the bridge for predicting motion of real ships and as training tool in ship handling simulators
International sea transport has growing rapidly dur-ing the period of the last decade. Ships became larg-er and wider and its container capacity is still in-creasing to 12.000 TEU and even more. To navigat
An introduction into optimal control for quantum technologies
In this series of lectures, we would like to introduce the audience to
quantum optimal control. The first lecture will cover basic ideas and
principles of optimal control with the goal of demystifying its jargon. The
second lecture will describe computational tools (for computations both on
paper and in a computer) for its implementation as well as their conceptual
background. The third chapter will go through a series of popular examples from
different applications of quantum technology.Comment: Lecture notes for the 51st IFF Spring Schoo
Structure and function in flow networks
Peer reviewedPublisher PD
Generalized vortex-model for the inverse cascade of two-dimensional turbulence
We generalize Kirchhoff's point vortex model of two-dimensional fluid motion
to a rotor model which exhibits an inverse cascade by the formation of rotor
clusters. A rotor is composed of two vortices with like-signed circulations
glued together by an overdamped spring. The model is motivated by a treatment
of the vorticity equation representing the vorticity field as a superposition
of vortices with elliptic Gaussian shapes of variable widths, augmented by a
suitable forcing mechanism. The rotor model opens up the way to discuss the
energy transport in the inverse cascade on the basis of dynamical systems
theory.Comment: 14 pages, 21 figure
High-Precision Entropy Values for Spanning Trees in Lattices
Shrock and Wu have given numerical values for the exponential growth rate of
the number of spanning trees in Euclidean lattices. We give a new technique for
numerical evaluation that gives much more precise values, together with
rigorous bounds on the accuracy. In particular, the new values resolve one of
their questions.Comment: 7 pages. Revision mentions alternative approach. Title changed
slightly. 2nd revision corrects first displayed equatio
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The Flow Field Upstream Of A Horizontal Axis Wind Turbine
A mathematical model is developed for a steady-state axi-symmetric upstream flow of a porous disc, in a uniform flow field . The special case of the upstream flow of a windmill, with and without a nacelle, is treated. First, the windmill is considered as a uniform distribution of sources and then as a linear distribution of sources. Solutions for the blade disc o f the wind field upstream are obtained in the form of stream1 ines and velocity vector components. Sample flow patterns upstream o f the blade disc o f the UMass 25 kW wind turbine are presented for several power levels. Documented computer programs applicable to any wind turbine are appended
Passive-performance, analysis, and upgrades of a 1-ton seismic attenuation system
The 10m Prototype facility at the Albert-Einstein-Institute (AEI) in Hanover,
Germany, employs three large seismic attenuation systems to reduce mechanical
motion. The AEI Seismic-Attenuation-System (AEI-SAS) uses mechanical
anti-springs in order to achieve resonance frequencies below 0.5Hz. This system
provides passive isolation from ground motion by a factor of about 400 in the
horizontal direction at 4Hz and in the vertical direction at 9Hz. The presented
isolation performance is measured under vacuum conditions using a combination
of commercial and custom-made inertial sensors. Detailed analysis of this
performance led to the design and implementation of tuned dampers to mitigate
the effect of the unavoidable higher order modes of the system. These dampers
reduce RMS motion substantially in the frequency range between 10 and 100Hz in
6 degrees of freedom. The results presented here demonstrate that the AEI-SAS
provides substantial passive isolation at all the fundamental mirror-suspension
resonances
Kinetic theory of point vortex systems from the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy
Kinetic equations are derived from the Bogoliubov-Born-Green-Kirkwood-Yvon
(BBGKY) hierarchy for point vortex systems in an infinite plane. As the level
of approximation for the Landau equation, the collision term of the kinetic
equation derived coincides with that by Chavanis ({\it Phys. Rev. E} {\bf 64},
026309 (2001)). Furthermore, we derive a kinetic equation corresponding to the
Balescu-Lenard equation for plasmas, using the theory of the Fredholm integral
equation. For large , this kinetic equation is reduced to the Landau
equation above.Comment: 10 pages, No figures. To be published in Physical Review E, 76-
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