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

Inequality aversion among Spanish gypsies: an experimental approach [Aversión a la desigualdad entre gitanos Españoles: un enfoque experimental]

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 practice, 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

Evaluating indices of traditional ecological knowledge: a methodological contribution

BACKGROUND: New quantitative methods to collect and analyze data have produced novel findings in ethnobiology. A common application of quantitative methods in ethnobiology is to assess the traditional ecological knowledge of individuals. Few studies have addressed reliability of indices of traditional ecological knowledge constructed with different quantitative methods. METHODS: We assessed the associations among eight indices of traditional ecological knowledge from data collected from 650 native Amazonians. We computed Spearman correlations, Chronbach's alpha, and principal components factor analysis for the eight indices. RESULTS: We found that indices derived from different raw data were weakly correlated (rho<0.5), whereas indices derived from the same raw data were highly correlated (rho>0.5; p < 0.001). We also found a relatively high internal consistency across data from the eight indices (Chronbach's alpha = 0.78). Last, results from a principal components factor analysis of the eight indices suggest that the eight indices were positively related, although the association was low when considering only the first factor. CONCLUSION: A possible explanation for the relatively low correlation between indices derived from different raw data, but relatively high internal consistency of the eight indices is that the methods capture different aspects of an individual's traditional ecological knowledge. To develop a reliable measure of traditional ecological knowledge, researchers should collect raw data using a variety of methods and then generate an aggregated measure that contains data from the various components of traditional ecological knowledge. Failure to do this will hinder cross-cultural comparisons

Solar cycle variations of large frequency separations of acoustic modes: Implications for asteroseismology

We have studied solar cycle changes in the large frequency separations that can be observed in Birmingham Solar Oscillations Network (BiSON) data. The large frequency separation is often one of the first outputs from asteroseismic studies because it can help constrain stellar properties like mass and radius. We have used three methods for estimating the large separations: use of individual p-mode frequencies, computation of the autocorrelation of frequency-power spectra, and computation of the power spectrum of the power spectrum. The values of the large separations obtained by the different methods are offset from each other and have differing sensitivities to the realization noise. A simple model was used to predict solar cycle variations in the large separations, indicating that the variations are due to the well-known solar cycle changes to mode frequency. However, this model is only valid over a restricted frequency range. We discuss the implications of these results for asteroseismology.Comment: 9 pages, 11 figures, accepted for publication in MNRAS, references updated, corrections following proof

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

Burning in the management of heathlands of Erica ciliaris and Erica tetralix: effects on structure and diversity

Can controlled burning be used as a management tool of Erica ciliaris and Erica tetralix wet heathlands? Two E. ciliaris and E. tetralix communities were selected and two 5 x 5 m plots were established in each. These were then characterised on the basis of frequency and cover values and plant species composition. They were subjected to experimental burning, after which the plots were sampled twice a year during the following four and a half years. The results show that the cover of woody species very quickly attained the values of the Control Plots. Diversity and species composition did not suffer notable changes during this period, however, temporal heterogeneity indicates that the main changes occur in the first 18 months of secondary succession. The multivariate analysis showed that the samples registered during this time were grouped as a function of the cover values of the species, which shows that stages exist in the vegetation recovery of these communities. The damage produced by fire in the community is minor, as a rapid recovery of the vegetation was observed, so controlled burning is a useful tool in the management of these heathlands

Reliability of P mode event classification using contemporaneous BiSON and GOLF observations

We carried out a comparison of the signals seen in contemporaneous BiSON and GOLF data sets. Both instruments perform Doppler shift velocity measurements in integrated sunlight, although BiSON perform measurements from the two wings of potassium absorption line and GOLF from one wing of the NaD1 line. Discrepancies between the two datasets have been observed. We show,in fact, that the relative power depends on the wing in which GOLF data observes. During the blue wing period, the relative power is much higher than in BiSON datasets, while a good agreement has been observed during the red period.Comment: 7 pages, HELAS II: Helioseismology, Asteroseismology, and MHD Connections, conference proceedin

Potential impacts of climate variability on Dengue Hemorrhagic Fever in Honduras, 2010

Climate change and variability are affecting human health and disease direct or indirectly through many mechanisms. Dengue is one of those diseases that is strongly influenced by climate variability; however its study in Central America has been poorly approached. In this study, we assessed potential associations between macroclimatic and microclimatic variation and dengue hemorrhagic fever (DHF) cases in the main hospital of Honduras during 2010. In this year, 3,353 cases of DHF were reported in the Hospital Escuela, Tegucigalpa. Climatic periods marked a difference of 158% in the mean incidence of cases, from El Niño weeks (-99% of cases below the mean incidence) to La Niña months (+59% of cases above it) (p<0.01). Linear regression showed significantly higher dengue incidence with lower values of Oceanic Niño Index (p=0.0097), higher rain probability (p=0.0149), accumulated rain (p=0.0443) and higher relative humidity (p=0.0292). At a multiple linear regression model using those variables, ONI values shown to be the most important and significant factor found to be associated with the monthly occurrence of DHF cases (r2=0.649; βstandardized=–0.836; p=0.01). As has been shown herein, climate variability is an important element influencing the dengue epidemiology in Honduras. However, it is necessary to extend these studies in this and other countries in the Central America region, because these models can be applied for surveillance as well as for prediction of dengue

High overlap between traditional ecological knowledge and forest conservation found in the Bolivian Amazon

Unidad de excelencia María de Maeztu MdM-2015-0552Altres ajuts: FBBVA research grant (BIOCON_06_106-07)It has been suggested that traditional ecological knowledge (TEK) may play a key role in forest conservation. However, empirical studies assessing to what extent TEK is associated with forest conservation compared with other variables are rare. Furthermore, to our knowledge, the spatial overlap of TEK and forest conservation has not been evaluated at fine scales. In this paper, we address both issues through a case study with Tsimane' Amerindians in the Bolivian Amazon. We sampled 624 households across 59 villages to estimate TEK and used remote sensing data to assess forest conservation. We ran statistical and spatial analyses to evaluate whether TEK was associated and spatially overlapped with forest conservation at the village level. We find that Tsimane' TEK is significantly and positively associated with forest conservation although acculturation variables bear stronger and negative associations with forest conservation. We also find a very significant spatial overlap between levels of Tsimane' TEK and forest conservation. We discuss the potential reasons underpinning our results, which provide insights that may be useful for informing policies in the realms of development, conservation, and climate. We posit that the protection of indigenous cultural systems is vital and urgent to create more effective policies in such realms

Effect of the photoperiod on the glutamate level in the suprachiasmatic nucleus of pregnant and non-pregnant rabbits

[EN] Microdialysis sampling was used to measure the glutamate level (GLU) contained in the suprachiasmatic nucleus (SCN) in 10 pregnant and 10 non-pregnant, subjected to either a 16:8 h light-dark cycle or a 12 h advanced photoperiod. Results revealed that GLU levels were significantly greater in samples taken for 2 h (15 min intervals), ¿60, ¿45 and ¿30 min before parturition (P<0.009, P<0.04, P<0.02), and +45 and +60 min after birth (P<0.009, P<0.05) respectively, in pregnant rabbits subjects to a 16:8 LD photoperiod (with light from 6:00-22:00 h). Parturition in these animals occurred at day 31 of gestation. Pregnant rabbits exposed to 12 h advanced photoperiod showed lower GLU levels in the SCN, and a longer gestation period and parturition process. In non-pregnant rabbits the GLU levels in the SCN were also significantly higher (P<0.009, in all samples) in comparison with rabbits subjected to the 12 h shifted photoperiod. It is possible that the photoperiod may have influenced GLU levels, and consequently, the length of gestation, the number of young and the time of birth. However, further studies involving new biotechnologies and a greater number of animals are needed to confirm these results.Reyes-Guerrero, G.; Vázquez-García, M.; Calderón-Guzmán, D.; Donatti-Albarrán, O.; Guevara-Guzmán, R. (2008). Effect of the photoperiod on the glutamate level in the suprachiasmatic nucleus of pregnant and non-pregnant rabbits. World Rabbit Science. 16(3). doi:10.4995/wrs.2008.62316