Holistic corpus-based dialectology

This paper is concerned with sketching future directions for corpus-based dialectology. We advocate a holistic approach to the study of geographically conditioned linguistic variability, and we present a suitable methodology, 'corpusbased dialectometry', in exactly this spirit. Specifically, we argue that in order to live up to the potential of the corpus-based method, practitioners need to (i) abandon their exclusive focus on individual linguistic features in favor of the study of feature aggregates, (ii) draw on computationally advanced multivariate analysis techniques (such as multidimensional scaling, cluster analysis, and principal component analysis), and (iii) aid interpretation of empirical results by marshalling state-of-the-art data visualization techniques. To exemplify this line of analysis, we present a case study which explores joint frequency variability of 57 morphosyntax features in 34 dialects all over Great Britain.Este artigo debruça-se sobre o esboço propositivo de futuras direções para a dialetologia baseada em corpus. Defendemos uma abordagem holística para o estudo da variabilidade linguística geograficamente condicionada, e apresentamos uma metodologia adequada para tal - a dialetometria baseada em corpus. Mais especificamente, defendemos que para que se obtenham todos os resultados esperados da metodologia de corpus, pesquisadores devem: (i) abandonar seu foco exclusivo em traços linguísticos individuais em favor do estudo dos agregados de traços, (ii) amparar-se em métodos computacionais avançados de técnicas de análise multivariada (tais como escalagem multidimensional, análise de clusters, e análise de componente principal), e (iii) auxiliar a interpretação de resultados empíricos através da utilização do estado da arte em técnicas de visualização. A fim de exemplificarmos essa linha de análise, apresentamos um estudo de caso que explora a variabilidade da frequência agregada de 57 traços morfossintáticos de 34 dialetos da Grã-Bretanha

Planets spinning up their host stars: a twist on the age-activity relationship

It is a long-standing question in exoplanet research if Hot Jupiters can influence the magnetic activity of their host stars. While cool stars usually spin down with age and become inactive, an input of angular momentum through tidal interaction, as seen for example in close binaries, can preserve high activity levels over time. This may also be the case for cool stars hosting a Hot Jupiter. However, selection effects from planet detection methods often dominate the activity levels seen in samples of exoplanet host stars, and planet-induced, systematically enhanced stellar activity has not been detected unambiguously so far. We have developed an approach to identify planet-induced stellar spin-up avoiding the selection biases from planet detection, by using visual proper motion binaries in which only one of the stars possesses a Hot Jupiter. This approach immediately rids one of the ambiguities of detection biases: with two co-eval stars, the second star acts as a negative control. We present results from our ongoing observational campaign at X-ray wavelengths and in the optical, and present several outstanding systems which display significant age/activity discrepancies presumably caused by their Hot Jupiters.Comment: 4 pages; to be published in the Proceedings of IAUS 302: Magnetic Fields Throughout Stellar Evolutio

Spitzer observations of Bow Shocks and Outflows in RCW 38

We report Spitzer observations of five newly identified bow shocks in the massive star-forming region RCW 38. Four are visible at IRAC wavelengths, the fifth is visible only at 24 microns. Chandra X-ray emission indicates that winds from the central O5.5 binary, IRS~2, have caused an outflow to the NE and SW of the central subcluster. The southern lobe of hot ionised gas is detected in X-rays; shocked gas and heated dust from the shock-front are detected with Spitzer at 4.5 and 24 microns. The northern outflow may have initiated the present generation of star formation, based on the filamentary distribution of the protostars in the central subcluster. Further, the bow-shock driving star, YSO 129, is photo-evaporating a pillar of gas and dust. No point sources are identified within this pillar at near- to mid-IR wavelengths. We also report on IRAC 3.6 & 5.8 micron observations of the cluster DBS2003-124, NE of RCW 38, where 33 candidate YSOs are identified. One star associated with the cluster drives a parsec-scale jet. Two candidate HH objects associated with the jet are visible at IRAC and MIPS wavelengths. The jet extends over a distance of ~3 pc. Assuming a velocity of 100 km/s for the jet material gives an age of about 30,000 years, indicating that the star (and cluster) are likely to be very young, with a similar or possibly younger age than RCW 38, and that star formation is ongoing in the extended RCW 38 region.Comment: 27 pages, 6 figures, accepted to Ap

The role of monetary incentives in prediction markets: a time series approach

Prediction markets serve as popular devices to aggregate beliefs and to assess market estimated probabilities. By looking at the interaction between real- and play-money prediction markets, this paper shows that traded volume has a significant positive effect on the probability of real- and play-money market cointegration. This indicates that the information aggregation process, eliminating individual traders'' biases, operates even when not inducing truthful belief revelation with monetary incentives. The study is based on data from four markets covering the 2008 presidential election in the United States of Americafinancial economics and financial management ;

Changing Urban High Schools

This report chronicles a Cross City Campaign working meeting co-sponsored by the Annenberg Institute for School Reform

The Impact of Non-Gaussianity upon Cosmological Forecasts

The primary science driver for 3D galaxy surveys is their potential to constrain cosmological parameters. Forecasts of these surveys' effectiveness typically assume Gaussian statistics for the underlying matter density, despite the fact that the actual distribution is decidedly non-Gaussian. To quantify the effect of this assumption, we employ an analytic expression for the power spectrum covariance matrix to calculate the Fisher information for BAO-type model surveys. We find that for typical number densities, at $k_\mathrm{max} = 0.5 h$ Mpc$^{-1}$, Gaussian assumptions significantly overestimate the information on all parameters considered, in some cases by up to an order of magnitude. However, after marginalizing over a six-parameter set, the form of the covariance matrix (dictated by $N$-body simulations) causes the majority of the effect to shift to the "amplitude-like" parameters, leaving the others virtually unaffected. We find that Gaussian assumptions at such wavenumbers can underestimate the dark energy parameter errors by well over 50 per cent, producing dark energy figures of merit almost 3 times too large. Thus, for 3D galaxy surveys probing the non-linear regime, proper consideration of non-Gaussian effects is essential.Comment: 9 pages, 5 figures, submitted to MNRA

Smooth X-ray variability from ρ\rho Ophiuchi A+B. A strongly magnetized primary B2 star?

X-rays from massive stars are ubiquitous yet not clearly understood. In an XMM-Newton observation devoted to observe the first site of star formation in the $\rho$ Ophiuchi dark cloud, we detect smoothly variable X-ray emission from the B2IV+B2V system of $\rho$ Ophiuchi. Tentatively we assign the emission to the primary component. The light curve of the pn camera shows a first phase of low, almost steady rate, then a rise phase of duration of 10 ks, followed by a high rate phase. The variability is seen primarily in the band 1.0-8.0 keV while little variability is detected below 1 keV. The spectral analysis of the three phases reveals the presence of a hot component at 3.0 keV that adds up to two relatively cold components at 0.9 keV and 2.2 keV. We explain the smooth variability with the emergence of an extended active region on the surface of the primary star due to its fast rotation (v $sin~i \sim315$ km/s). We estimate that the region has diameter in the range $0.5-0.6$ R$_*$. The hard X-ray emission and its variability hint a magnetic origin, as suggested for few other late-O$-$early-B type stars. We also discuss an alternative explanation based on the emergence from occultation of a young (5-10 Myr) low mass companion bright and hot in X-rays.Comment: 4 pages, 3 figures, 2 tables. Accepted for publication as a letter in A&

The early B-type star Rho Oph A is an X-ray lighthouse

We present the results of a 140 ks XMM-Newton observation of the B2 star $\rho$ Ophiuchi A. The star has exhibited strong X-ray variability: a cusp-shaped increase of rate, similar to that which we partially observed in 2013, and a bright flare. These events are separated in time by about 104 ks, which likely corresponds to the rotational period of the star (1.2 days). Time resolved spectroscopy of the X-ray spectra shows that the first event is caused by an increase of the plasma emission measure, while the second increase of rate is a major flare with temperatures in excess of 60 MK ($kT\sim5$ keV). From the analysis of its rise, we infer a magnetic field of $\ge300$ G and a size of the flaring region of $\sim1.4-1.9\times10^{11}$ cm, which corresponds to $\sim25\%-30\%$ of the stellar radius. We speculate that either an intrinsic magnetism that produces a hot spot on its surface or an unknown low mass companion are the source of such X-rays and variability. A hot spot of magnetic origin should be a stable structure over a time span of $\ge$2.5 years, and suggests an overall large scale dipolar magnetic field that produces an extended feature on the stellar surface. In the second scenario, a low mass unknown companion is the emitter of X-rays and it should orbit extremely close to the surface of the primary in a locked spin-orbit configuration, almost on the verge of collapsing onto the primary. As such, the X-ray activity of the secondary star would be enhanced by its young age, and the tight orbit as in RS Cvn systems and $\rho$ Ophiuchi would constitute an extreme system that is worthy of further investigation.Comment: 10 pages, 7 figures, 2 tables, A&A accepted, this is the version after the language editor correction