The X-ray cycle in the solar-type star HD 81809

(abridged) Our long-term XMM-Newton program of long-term monitoring of a solar-like star with a well-studied chromospheric cycle, HD 81809 aims to study whether an X-ray cycle is present, along with studying its characteristics and its relation to the chromospheric cycle. Regular observations of HD 81809 were performed with XMM-Newton, spaced by 6 months from 2001 to 2007. We studied the variations in the resulting coronal luminosity and temperature, and compared them with the chromospheric CaII variations. We also modeled the observations in terms of a mixture of active regions, using a methodology originally developed to study the solar corona. Our observations show a well-defined cycle with an amplitude exceeding 1 dex and an average luminosity approximately one order of magnitude higher than in the Sun. The behavior of the corona of HD 81809 can be modeled well in terms of varying coverage of solar-like active regions, with a larger coverage than for the Sun, showing it to be compatible with a simple extension of the solar case.Comment: In press, Astronomy & Astrophysic

Preparation for Discipleship- Discipleship in Jesus\u27 Farewell Discourses, St John13-17

The meaning of discipleship is significant for the church today. As the world changes, the church and the members of the church change, and it becomes necessary for the church to renew her churchliness. In order to be the church, the church must know the meaning of discipleship. If the church wants to understand her divine duty she must know the meaning of discipleship. This thesis presents an investigation of the meaning of discipleship in Jesus\u27 farewell discourses in the Gospel according to St. John (chapters 13-17)

Convening a Constitutional Convention in Washington Through the Use of the Popular Initative

Using Washington as a model for discussion this comment explores the doctrines which have limited the application of the flexible principles of popular sovereignty to the problems presented in the calling of a Constitutional Convention. The author concludes: that the people of the state of Washington can call such a convention by the use of the popular initiative; that earlier notions that changes in state governmental structure could only be accomplished by strict conformity to the procedures in the existing constitution have been supplanted by the resurgence of the doctrines of popular sovereignty; and that the broad theoretical underpinnings for popular sovereignty decry the soundness of the application of any maxims of interpretation which would deny the people, acting through the initiative, the power to call a Constitutional Convention

High-amplitude, long-term X-ray variability in the solar-type star HD 81809: the beginning of an X-ray activity cycle?

We present the initial results from our XMM program aimed at searching for X-ray activity cycles in solar-type stars. HD 81809 is a G2-type star (somewhat more evolved than the Sun, and with a less massive companion) with a pronounced 8.2 yr chromospheric cycle, as evident from from the Mt. Wilson program data. We present here the results from the initial 2.5 years of XMM observations, showing that large amplitude (a factor of approx. 10) modulation is present in the X-ray luminosity, with a clearly defined maximum in mid 2002 and a steady decrease since then. The maximum of the chromospheric cycle took place in 2001; if the observed X-ray variability is the initial part of an X-ray cycle, this could imply a phase shift between chromospheric and coronal activity, although the current descent into chromospheric cycle minimum is well reflected into the star's X-ray luminosity. The observations presented here provide clear evidence for the presence of large amplitude X-ray variability coherent with the activity cycle in the chromosphere in a star other than the Sun.Comment: Accepted for publication in A&

Humor with backgrounded incongruity: Does more required suspension of disbelief affect humor perception?

Humorous stimuli, like jokes and cartoons, are assumed to contain a central incongruity in a specific constellation of opposition and overlap that is essential to their humorousness. Many stimuli also contain additional incongruities that the audience usually overlooks, but that may be needed to create the setup for the main incongruity, e.g., animals that talk, space aliens, an Italian, an American, and a Russian sharing a language. Two of the studies described in the present paper investigated the effect of such backgrounded incongruities by removing them from a set of jokes and cartoons and testing how this affects humor processing and appreciation. A third study investigated whether the elimination of a backgrounded incongruity influences the position of a humorous stimulus on the incongruity-resolution and nonsense humor continuum. Methods included computer-based stimulus rating and self-explanations by the participants. The results suggested that backgrounded incongruities influence humor appreciation because their elimination leads to lower funniness and higher aversion. Furthermore, the backgrounded incongruities contribute strongly to the perceived absurdity of a joke. When they are removed, the jokes are perceived less to be nonsense humor but more as incongruity-resolution humo

Coronal activity cycles in nearby G and K stars - XMM-Newton monitoring of 61 Cygni and Alpha Centauri

We use X-ray observations of the nearby binaries 61 Cyg A/B (K5V and K7V) and Alpha Cen A/B (G2V and K1V) to study the long-term evolution of magnetic activity in weakly to moderately active G + K dwarfs over nearly a decade. Specifically we search for X-ray activity cycles and related coronal changes and compare them to the solar behavior. For 61 Cyg A we find a regular coronal activity cycle analog to its 7.3 yr chromospheric cycle. The X-ray brightness variations are with a factor of three significantly lower than on the Sun, yet the changes of coronal properties resemble the solar behavior with larger variations occurring in the respective hotter plasma components. 61 Cyg B does not show a clear cyclic coronal trend so far, but the X-ray data matches the more irregular chromospheric cycle. Both Alpha Cen stars exhibit significant long-term X-ray variability. Alpha Cen A shows indications for cyclic variability of an order of magnitude with a period of about 12-15 years; the Alpha Cen B data suggests an X-ray cycle with an amplitude of about six to eight and a period of 8-9 years. The sample stars exhibit X-ray luminosities ranging between Lx < 1x10^26 - 3x10^27 erg s^-1 in the 0.2-2.0 keV band and have coronae dominated by cool plasma with variable average temperatures of around 1.0-2.5 MK. We find that coronal activity cycles are apparently a common phenomenon in older, slowly rotating G and K stars. The spectral changes of the coronal X-ray emission over the cycles are solar-like in all studied targets.Comment: 11 pages, 9 figures, accepted by Astronomy and Astrophysic

Introduction to Quasielastic Neutron Scattering

This tutorial introduction has been written for people who are not specialized in neutron scattering or in other scattering methods but who are interested and would like to get an impression and learn about the method of Quasielastic Neutron Scattering (QENS). The theoretical (scattering process) as well as the experimental basics (neutron sources, neutron scattering instruments, experimental periphery) are explained in a generally understandable way, with only the most essential formulas. QENS addresses the stochastic dynamics in condensed matter, and it is pointed out for which problems and for which systems in condensed matter research QENS is a powerful method. Thus sufficient information is provided to enable non-experts to think about their own QENS experiment and to understand related literature in this area of researc