513 research outputs found
Immune function and parasite resistance in male and polymorphic female Coenagrion puella
Background:
Colour polymorphisms are widespread and one of the prime examples is the colour
polymorphism in female coenagrionid damselflies: one female morph resembles the male colour
(andromorph) while one, or more, female morphs are described as typically female (gynomorph).
However, the selective pressures leading to the evolution and maintenance of this polymorphism
are not clear. Here, based on the hypothesis that coloration and especially black patterning can be
related to resistance against pathogens, we investigated the differences in immune function and
parasite resistance between the different female morphs and males.
Results:
Our studies of immune function revealed no differences in immune function between the
female morphs but between the sexes in adult damselflies. In an experimental infection females
infected shortly after emergence showed a higher resistance against a fungal pathogen than males,
however female morphs did not differ in resistance. In a field sample of adult damselflies we did not
find differences in infection rates with watermites and gregarines.
Conclusion:
With respect to resistance and immune function 'andromorph' blue females of
Coenagrion puella do not resemble the males. Therefore the colour polymorphism in coenagrionid
damselflies is unlikely to be maintained by differences in immunity
Conservation Laws in Higher-Order Nonlinear Optical Effects
Conservation laws of the nonlinear Schr\"{o}dinger equation are studied in
the presence of higher-order nonlinear optical effects including the
third-order dispersion and the self-steepening. In a context of group theory,
we derive a general expression for infinitely many conserved currents and
charges of the coupled higher-order nonlinear Schr\"{o}dinger equation. The
first few currents and charges are also presented explicitly. Due to the
higher-order effects, conservation laws of the nonlinear Schr\"{o}dinger
equation are violated in general. The differences between the types of the
conserved currents for the Hirota and the Sasa-Satsuma equations imply that the
higher-order terms determine the inherent types of conserved quantities for
each integrable cases of the higher-order nonlinear Schr\"{o}dinger equation
Switching dynamics of spatial solitary wave pixels
Separatrices and scaling laws in the switching dynamics of spatial solitary wave pixels are investigated. We show that the dynamics in the full model are similar to those in the plane-wave limit. Switching features may be indicated and explained by the motion of the (complex) solitary wave amplitude in the phase plane. We report generalization, into the domain of transverse effects, of the pulse area theorem for the switching process and a logarithmic law for the transient dynamics. We also consider, for what is the first time to our knowledge, phase-encoded address of solitary pixels and find that a near-square-wave temporal switching pattern is permitted without (transverse) cross switching
Conflict experience and resolution underlying obedience to authority
Definitions of obedience require the experience of conflict in response to an authority’s demands. Nevertheless, we know little about this conflict and its resolution. Two experiments tested the suitability of the ‘object-destruction paradigm’ for the study of conflict in obedience. An experimenter instructed participants to shred bugs (among other objects) in a manipulated coffee grinder. In contrast to the demand condition, participants in the control condition were reminded of their free choice. Both received several prods if they defied the experimenter. Results show that participants were more willing to kill bugs in the demand condition. Self-reported negative affect was increased after instructions to destroy bugs relative to other objects (Experiments 1 and 2). In Experiment 2, compliant participants additionally showed an increase in tonic skin conductance and, crucially, self-reported more agency and responsibility after alleged bug-destruction. These findings elucidate the conflict experience and resolution underlying obedience. Implications for prominent explanations (agentic shift, engaged followership) are discussed
Conflict experience and resolution underlying obedience to authority
Definitions of obedience require the experience of conflict in response to an authority’s demands. Nevertheless, we know little about this conflict and its resolution. Two experiments tested the suitability of the ‘object-destruction paradigm’ for the study of conflict in obedience. An experimenter instructed participants to shred bugs (among other objects) in a manipulated coffee grinder. In contrast to the demand condition, participants in the control condition were reminded of their free choice. Both received several prods if they defied the experimenter. Results show that participants were more willing to kill bugs in the demand condition. Self-reported negative affect was increased after instructions to destroy bugs relative to other objects (Experiments 1 and 2). In Experiment 2, compliant participants additionally showed an increase in tonic skin conductance and, crucially, self-reported more agency and responsibility after alleged bug-destruction. These findings elucidate the conflict experience and resolution underlying obedience. Implications for prominent explanations (agentic shift, engaged followership) are discussed
Optical Solitary Waves in the Higher Order Nonlinear Schrodinger Equation
We study solitary wave solutions of the higher order nonlinear Schrodinger
equation for the propagation of short light pulses in an optical fiber. Using a
scaling transformation we reduce the equation to a two-parameter canonical
form. Solitary wave (1-soliton) solutions exist provided easily met inequality
constraints on the parameters in the equation are satisfied. Conditions for the
existence of N-soliton solutions (N>1) are determined; when these conditions
are met the equation becomes the modified KdV equation. A proper subset of
these conditions meet the Painleve plausibility conditions for integrability.Comment: REVTeX, 4 pages, no figures. To appear in Phys. Rev. Let
Multisoliton solutions and integrability aspects of coupled nonlinear Schrodinger equations
Using Painleve singularity structure analysis, we show that coupled
higher-order nonlinear Schrodinger (CHNLS) equations admit Painleve property.
Using the results of Painleve analysis, we succeed in Hirota bilinearizing the
CHNLS equations, one soliton and two soliton solutions are explictly obtained.
Lax pairs are explictly constructed.Comment: Eight pages and six figures. Physical Review E (to be appear
Experimental feasibility of measuring the gravitational redshift of light using dispersion in optical fibers
This paper describes a new class of experiments that use dispersion in
optical fibers to convert the gravitational frequency shift of light into a
measurable phase shift or time delay. Two conceptual models are explored. In
the first model, long counter-propagating pulses are used in a vertical fiber
optic Sagnac interferometer. The second model uses optical solitons in
vertically separated fiber optic storage rings. We discuss the feasibility of
using such an instrument to make a high precision measurement of the
gravitational frequency shift of light.Comment: 11 pages, 12 figure
Toward Global Quantum Communication: Beam Wandering Preserves Nonclassicality
Tap-proof long-distance quantum communication requires a deep understanding
of the strong losses in transmission channels. Here we provide a rigorous
treatment of the effects of beam wandering, one of the leading disturbances in
atmospheric channels, on the quantum properties of light. From first principles
we derive the probability distribution of the beam transmissivity, with the aim
to completely characterize the quantum state of light. It turns out that beam
wandering may preserve nonclassical effects, such as entanglement, quadrature
and photon number squeezing, much better than a standard attenuating channel of
the same losses.Comment: published versio
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