852 research outputs found
Effect of various levels of Ralgro on reproductive performance of yearling heifers
Implanting heifers at weaning time with 12, 24, or 36 mg of Ralgro did not affect reproductive performance of the heifers when bred as yearlings
Geometric and dynamic perspectives on phase-coherent and noncoherent chaos
Statistically distinguishing between phase-coherent and noncoherent chaotic
dynamics from time series is a contemporary problem in nonlinear sciences. In
this work, we propose different measures based on recurrence properties of
recorded trajectories, which characterize the underlying systems from both
geometric and dynamic viewpoints. The potentials of the individual measures for
discriminating phase-coherent and noncoherent chaotic oscillations are
discussed. A detailed numerical analysis is performed for the chaotic R\"ossler
system, which displays both types of chaos as one control parameter is varied,
and the Mackey-Glass system as an example of a time-delay system with
noncoherent chaos. Our results demonstrate that especially geometric measures
from recurrence network analysis are well suited for tracing transitions
between spiral- and screw-type chaos, a common route from phase-coherent to
noncoherent chaos also found in other nonlinear oscillators. A detailed
explanation of the observed behavior in terms of attractor geometry is given.Comment: 12 pages, 13 figure
Magnetic shielding for the bendix resistance strip multiplier
Magnetic shielding for electron resistance strip multiplie
Estrus synchronization of cattle in Kansas
In 22 field trials involving 1,692 cattle, we evaluated Lutalyse as an estrus-synchronization agent for both natural mating and artificial insemination. Only 52.7% of the females in all 22 trials were cycling at the start of the breeding season. Both body condition and days postpartum at the start of the breeding season influenced the response to Lutalyse. First-service pregnancy rate in the 2 or 3 days of synchronization was 38.4% for all 453 females bred artificially in 12 trials in northwestern Kansas. The rate was 59%, however, if only females observed to be in heat were counted; but only 24.5% if only those in which no heat was observed were counted
Pulsive feedback control for stabilizing unstable periodic orbits in a nonlinear oscillator with a non-symmetric potential
We examine a strange chaotic attractor and its unstable periodic orbits in
case of one degree of freedom nonlinear oscillator with non symmetric
potential. We propose an efficient method of chaos control stabilizing these
orbits by a pulsive feedback technique. Discrete set of pulses enable us to
transfer the system from one periodic state to another.Comment: 11 pages, 4 figure
Computing the multifractal spectrum from time series: An algorithmic approach
We show that the existing methods for computing the f(\alpha) spectrum from a
time series can be improved by using a new algorithmic scheme. The scheme
relies on the basic idea that the smooth convex profile of a typical f(\alpha)
spectrum can be fitted with an analytic function involving a set of four
independent parameters. While the standard existing schemes [16, 18] generally
compute only an incomplete f(\alpha) spectrum (usually the top portion), we
show that this can be overcome by an algorithmic approach which is automated to
compute the Dq and f(\alpha) spectrum from a time series for any embedding
dimension. The scheme is first tested with the logistic attractor with known
f(\alpha) curve and subsequently applied to higher dimensional cases. We also
show that the scheme can be effectively adapted for analysing practcal time
series involving noise, with examples from two widely different real world
systems. Moreover, some preliminary results indicating that the set of four
independant parameters may be used as diagnostic measures is also included.Comment: 10 pages, 16 figures, submitted to CHAO
Persistent Chaos in High Dimensions
An extensive statistical survey of universal approximators shows that as the
dimension of a typical dissipative dynamical system is increased, the number of
positive Lyapunov exponents increases monotonically and the number of parameter
windows with periodic behavior decreases. A subset of parameter space remains
in which topological change induced by small parameter variation is very
common. It turns out, however, that if the system's dimension is sufficiently
high, this inevitable, and expected, topological change is never catastrophic,
in the sense chaotic behavior is preserved. One concludes that deterministic
chaos is persistent in high dimensions.Comment: 4 pages, 3 figures; Changes in response to referee comment
Effects of non-denumerable fixed points in finite dynamical systems
The motion of a spinning football brings forth the possible existence of a
whole class of finite dynamical systems where there may be non-denumerably
infinite number of fixed points. They defy the very traditional meaning of the
fixed point that a point on the fixed point in the phase space should remain
there forever, for, a fixed point can evolve as well! Under such considerations
one can argue that a free-kicked football should be non-chaotic.Comment: This paper is a replaced version to modify the not-so-true claim,
made unknowingly in the earlier version, of being first to propose the
peculiar dynamical systems as described in the paper. With respect to the
original workers, we present here our original finding
Description of stochastic and chaotic series using visibility graphs
Nonlinear time series analysis is an active field of research that studies
the structure of complex signals in order to derive information of the process
that generated those series, for understanding, modeling and forecasting
purposes. In the last years, some methods mapping time series to network
representations have been proposed. The purpose is to investigate on the
properties of the series through graph theoretical tools recently developed in
the core of the celebrated complex network theory. Among some other methods,
the so-called visibility algorithm has received much attention, since it has
been shown that series correlations are captured by the algorithm and
translated in the associated graph, opening the possibility of building
fruitful connections between time series analysis, nonlinear dynamics, and
graph theory. Here we use the horizontal visibility algorithm to characterize
and distinguish between correlated stochastic, uncorrelated and chaotic
processes. We show that in every case the series maps into a graph with
exponential degree distribution P (k) ~ exp(-{\lambda}k), where the value of
{\lambda} characterizes the specific process. The frontier between chaotic and
correlated stochastic processes, {\lambda} = ln(3/2), can be calculated
exactly, and some other analytical developments confirm the results provided by
extensive numerical simulations and (short) experimental time series
Archaeosome Adjuvant Overcomes Tolerance to Tumor-Associated Melanoma Antigens Inducing Protective CD8+ T Cell Responses
Vesicles comprised of the ether glycerolipids of the archaeon Methanobrevibacter smithii (archaeosomes) are potent adjuvants for evoking CD8+ T cell responses. We therefore explored the ability of archaeosomes to overcome immunologic tolerance to self-antigens. Priming and boosting of mice with archaeosome-antigen evoked comparable CD8+ T cell response and tumor protection to an alternate boosting strategy utilizing live bacterial vectors for antigen delivery. Vaccination with melanoma antigenic peptides TRP181-189 and Gp10025-33 delivered in archaeosomes resulted in IFN-γ producing antigen-specific CD8+ T cells with strong cytolytic capability and protection against subcutaneous B16 melanoma. Targeting responses against multiple antigens afforded prolonged median survival against melanoma challenge. Entrapment of multiple peptides within the same vesicle or admixed formulations were both effective at evoking CD8+ T cells against each antigen. Melanoma-antigen archaeosome formulations also afforded therapeutic protection against established B16 tumors when combined with depletion of T-regulatory cells. Overall, we demonstrate that archaeosome adjuvants constitute an effective choice for formulating cancer vaccines
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