The onset of solar cycle 24: What global acoustic modes are telling us

We study the response of the low-degree, solar p-mode frequencies to the unusually extended minimum of solar surface activity since 2007. A total of 4768 days of observations collected by the space-based, Sun-as-a-star helioseismic GOLF instrument are analyzed. A multi-step iterative maximum-likelihood fitting method is applied to subseries of 365 days and 91.25 days to extract the p-mode parameters. Temporal variations of the l=0, 1, and 2 p-mode frequencies are then obtained from April 1996 to May 2009. While the p-mode frequency shifts are closely correlated with solar surface activity proxies during the past solar cycles, the frequency shifts of the l=0 and l=2 modes show an increase from the second half of 2007, when no significant surface activity is observable. On the other hand, the l=1 modes follow the general decreasing trend of the solar surface activity. The different behaviours between the l=0 and l=2 modes and the l=1 modes can be interpreted as different geometrical responses to the spatial distribution of the solar magnetic field beneath the surface of the Sun. The analysis of the low-degree, solar p-mode frequency shifts indicates that the solar activity cycle 24 started late 2007, despite the absence of activity on the solar surface.Comment: To be accepted by A&A (with minor revisions), 4 pages, 3 figures, 1 tabl

A seismic signature of a second dynamo?

The Sun is a variable star whose magnetic activity varies most perceptibly on a timescale of approximately 11 years. However, significant variation is also observed on much shorter timescales. We observe a quasi-biennial (2 year) signal in the natural oscillation frequencies of the Sun. The oscillation frequencies are sensitive probes of the solar interior and so by studying them we can gain information about conditions beneath the solar surface. Our results point strongly to the 2 year signal being distinct and separate from, but nevertheless susceptible to the influence of, the main 11 year solar cycle.Comment: Accepted for publication in ApJL, 5 pages, 2 figure

The dark side of friendship: envy

This paper studies the e¤ect of social relations on the convergence to the e¢ cient equilibrium in a 2x2 coordination game. We employ a 2x2 factorial design in which we explore two di¤erent games with asymmetric payo¤s and two matching protocols: .friends.versus .strangers.. In the .rst game payo¤s of the worse o¤ player are the same in the two equilibria, whereas in the second game, this player must sacri.ce her own payo¤ for achieving the e¢ cient equilibrium. Results show that .strangers. coor- dinate more frequently in the e¢ cient equilibrium than .friends.in both games. Regarding network measures, (such us degree in, degree out and betweenness) they are all positively correlated with the strategy which leads to the e¢ cient outcome except clustering. In addition, envy is a salient factor in explaining e¢ cient convergence.coordination, efficiency, envy, experiments, friendship, social networks.

Media coverage of climate change mitigation in the spanish press

This article analyzes how the Spanish press covers the mitigation of climate change. We have used the search engine MyNews to study in El País and El Mundo, the newspapers with the largest circulation in Spain during the years 2016 and 2017, the news that includes the words "mitigacion" o "reducción de emisiones", y "cambio climatico” o “calentamiento global" in the most circulation newspapers in Spain in 2016 and 2017: El País and El Mundo. To explain how mitigation is covered by the Spanish press, we have used a series of categories and variables. As a result, we find an important difference between the urgency expressed by the scientific community and the reduced presence of this topic in the Spanish press

Inequality aversion among gypsies: a field investigation

This paper presents a first attempt to measure inequality aversion among gypsies. We conducted an experiment among adult gypsies living at slums outside Vallecas (Madrid). To analyze this variable we use the mechanism provided by Kroll & Davidovitz (2003) among 38 voluntary participants. Results indicate that: i) 52.6% of the individuals are inequality averse; ii) there is a positive relationship between inequality aversion and some features of the population such as individual religious practise, marital status, family size, position in the hierarchy of the family or club association and, iii) neither wealth, nor participation in voluntary activities affect inequality aversion.inequality aversion, gypsies, field experiment.

Analysis of post-tensioned structures by means of a constitutive serial-parallel rule of mixtures

The main purpose is to test a reliable method based on a three-dimensional (3D) finite-element (FE) model to simulate the constitutive behavior of reinforced concrete structures strengthened with post-tensioned tendons. Large scale 3D FE models will be used, where the nonlinear material behavior and geometrical analysis based on incremental iterative load methods will be adopted

An investment game with third-party intervention

This paper explores the effect of the possibility of third-party intervention on behavior in a variant of the Berg, Dickhaut, and McCabe (1995) “Investment Game”. A third-party’s material payoff is not affected by the decisions made by the other participants, but this person may choose to punish a responder who has been overly selfish. The concern over this possibility may serve to discipline potentially-selfish responders. We also explore a treatment in which the third party may also choose to reward a sender who has received a low net payoff as a result of the responder’s action. We find a strong and significant effect of third-party punishment, in both punishment regimes, as the amount sent by the first mover is more than 60% higher when there is the possibility of third-party punishment. We also find that responders return a higher proportion of the amount sent to them when there is the possibility of punishment, with this proportion slightly higher when reward is not feasible. Finally, third parties punish less when reward is feasible, but nevertheless spend more on the combination of reward and punishment when these are both permitted than on punishment when this is the only choice for redressing material outcomes.Trust, punishment, third-party intervention, responsibility-alleviation

The acoustic cut-off frequency of the Sun and the solar magnetic activity cycle

The acoustic cut-off frequency -the highest frequency for acoustic solar eigenmodes- is an important parameter of the solar atmosphere as it determines the upper boundary of the p-mode resonant cavities. At frequencies beyond this value, acoustic disturbances are no longer trapped but traveling waves. Interference amongst them give rise to higher-frequency peaks -the pseudomodes- in the solar acoustic spectrum. The pseudomodes are shifted slightly in frequency with respect to p modes making possible the use of pseudomodes to determine the acoustic cut-off frequency. Using data from GOLF and VIRGO instruments on board the SOHO spacecraft, we calculate the acoustic cut-off frequency using the coherence function between both the velocity and intensity sets of data. By using data gathered by these instruments during the entire lifetime of the mission (1996 till the present), a variation in the acoustic cut-off frequency with the solar magnetic activity cycle is found.Comment: Paper accepted in ApJ. 26 Pages, 9 figure