Male-male competition over territorial ownership suggests that winning is associated with considerable benefits. In the speckled wood butterfly, Pararge aegeria, males fight over sunspot territories on the forest floor; winners gain sole residency of a sunspot, whereas losers patrol the forest in search of females. It is currently not known whether residents experience greater mating success th...

In a recent paper (Usoskin et al., 2002a), we have reconstructed the concentration of the cosmogenic 10 Be isotope in ice cores from the measured sunspot numbers by using physical models for 10 Be production in the Earth's atmosphere, cosmic ray transport in the heliosphere, and evolution of the Sun's open magnetic flux. Here we take the opposite route: starting from the 10 Be concentration mea...

[1] The historical record of sunspot areas is a valuable and widely used proxy of solar activity and variability. The Royal Greenwich Observatory regularly measured this and other parameters between 1874 and 1976. After that time records from a number of different observatories are available. These, however, show systematic differences and often have significant gaps. Our goal is to obtain a un...

As recently found, the distribution of sunspots is non-axisymmetric and spot group formation implies the existence of two persistent active longitudes separated by 180◦. Here we quantitatively study the non-axisymmetry of sunspot occurrence. In a dynamic reference frame inferred from the differential rotation law, the raw sunspot data show a clear clustering around the persistent active longitu...

Sunspots are the subject of interest to many astronomers and solar physicists. Sunspot observation, analysis and classification form an important part of furthering the knowledge about the Sun. Sunspot classification is a manual and very labor intensive process that could be automated if successfully learned by a machine. This paper presents machine learning approaches to the problem of sunspot...

More than 70 years ago, it was recognised that ionospheric F2-layer critical frequencies [foF2] had a strong relationship to sunspot number. Using historic datasets from the Slough and Washington ionosondes, we evaluate the best statistical fits of foF2 to sunspot numbers (at each Universal Time [UT] separately) in order to search for drifts and abrupt changes in the fit residuals over Solar Cy...

,4bstract.--This article is a continuation of the previous one by the authors on the same subject. With the aid of additional data, •t is once more found that the quantities a and b in the formula Q=aq-b $ vary with sunspot activity, and apparently also with time; Q is the measure of magnetic activity, and S that of solar activity. The parameter a varies directly, and b inversely with sunspot a...

An imperfectly competitive economy is very prone to market uncertainty, including uncertainty about the liquidity (or "thickness") of markets. We show, in particular, that there exist stochastic equilibrium outcomes in nonstochastic market games if (and only if) the endowments are not Pareto optimal. We also provide a link between extrinsic uncertainty arising in games (e.g. correlated equilibr...

Waldmeier [1971] found a very tight relationship between the F10.7 solar radio flux and the sunspot number and suggested using the flux for an objective calibration of the sunspot number. He suggested that if this relationship changed later on, the sunspot number should be recalibrated, assuming that the calibration must have drifted with time. I repeat his analysis using data up to the present...

This paper describes automatic sunspot recognition and classification from satellite images. Some experimental results on learning sunspot classification using data mining techniques are presented. The classification scheme attempted was the seven-class Modified Zurich scheme. Daily images of the solar disk were taken from the NASA SOHO satellite’s MDI instrument and sunspots extracted using im...