New ground-based observational methods and instrumentation for asteroseismology

Space instrumentation like SOHO, MOST, CoRoT and Kepler has been and is being built to attain very high precision data to be used for asteroseismic analysis. Nonetheless, there is a very strong need for providing additional information, especially on mode identification. With this contribution I will review the efforts been put on new ground-based instrumentation and the methodology that can be used to achieve this aim.Comment: 6 pages. Review contribution to be published in Astrophysics and Space Science Proceedings series (ASSP), in the proceedings of "20th Stellar Pulsation Conference Series: Impact of new instrumentation and new insights in stellar pulsations", 5-9 September 2011, Granada, Spai

On Electron-Positron Annihilation into Nucleon-Antinucleon Pairs

We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) >~ sigma(e+e- --> pbar p). We discuss an interpretation in terms of a two-step process, via an intermediate coherent isovector state serving as an intermediary between e+e- and the baryon-antibaryon system. We provide evidence that the isovector channel dominates both e+e- --> pions and from Nbar N annihilation at rest, and show that the observed ratio of sigma(e+e- --> nbar n)/sigma(e+e- --> pbarp p) can be understood quantitatively in this picture.Comment: 13 pages, 4 figure

Planets in Stellar Clusters Extensive Search. I. Discovery of 47 Low-amplitude Variables in the Metal-rich Cluster NGC 6791 with Millimagnitude Image Subtraction Photometry

We have undertaken a long-term project, Planets in Stellar Clusters Extensive Search (PISCES), to search for transiting planets in open clusters. As our first target we have chosen NGC 6791 -- a very old, populous, metal rich cluster. In this paper we present the results of a test observing run at the FLWO 1.2 m telescope. Our primary goal is to demonstrate the feasibility of obtaining the accuracy required for planetary transit detection using image subtraction photometry on data collected with a 1 m class telescope. We present a catalog of 62 variable stars, 47 of them newly discovered, most with low amplitude variability. Among those there are several BY Dra type variables. We have also observed outbursts in the cataclysmic variables B7 and B8 (Kaluzny et al. 1997).Comment: 15 pages LaTeX, including 8 PostScript figures and 3 tables. More discussion added on the implications for transit detection. Accepted for publication in the Astronomical Journal. Version with full resolution figures available through ftp at ftp://cfa-ftp.harvard.edu/pub/bmochejs/PISCES/papers/1_N6791

Análise comparativa dos ficocolóides produzidos por algas carragenófitas usadas industrialmente e algas carragenófitas portuguesas

As Carragenanas (E-407) constituem um dos principais aditivos usados pela indústria alimentar, como agentes gelificantes, emulsionantes, estabilizantes e espessantes. São ingredientes naturais, usados há várias décadas na área alimentar e são considerados como seguros, tendo obtido a classificação GRAS (Generally Recognised As Safe). Neste trabalho foram analisadas a percentagem de peso seco e a composição química (por FTIR e FT-Raman) das carragenanas produzidas pelas carragenófitas (Gigartinales, Rhodophyta) oriundas de diversos países: Kappaphycus alvarezzi (Tanzânia, Indonésia, Filipinas); Kappaphycus striatum (Madagáscar); Eucheuma denticulatum (Tanzânia, Filipinas e Madagáscar); Betaphycus gelatinum (Filipinas); e Sarcothalia crispata (Chile). Para comparação foram também analisadas algas carragenófitas da costa portuguesa (Gigartinales, Rhodophyta): Chondrus crispus, Mastocarpus stellatus; Gigartina pistillata; Chondracanthus teedei var. lusitanicus; Chondracanthus acicularis; Calliblepharis jubata; Gymnogongrus crenulatus; e Ahnfeltiopsis devoniensis. Os principais resultados a reter são: a maior percentagem de peso seco em carragenanas foi obtida a partir das algas carragenófitas Kappaphycus alvarezzi (Filipinas), com 84.4% e Gigartina pistillata (Praia do Norte, Viana do Castelo), com 65.4%. Relativamente à natureza dos ficocolóides produzidos pelas carragenófitas estudadas, as nossas análises espectroscópicas permitiram determinar a presença de um leque diversificado de carragenanas: carragenana iota pura; carragenana kappa quase pura; uma série de carragenanas híbridas kappa-iota, com diferentes rácios iota/kappa; carragenanas kappa-beta, xi-tetha e xi-lambda

Scanning the Parameter Space of Holographic Superconductors

We study various physical quantities associated with holographic s-wave superconductors as functions of the scaling dimensions of the dual condensates. A bulk scalar field with negative mass squared $m^2$, satisfying the Breitenlohner-Freedman stability bound and the unitarity bound, and allowed to vary in $0.5$ unit intervals, were considered. We observe that all the physical quantities investigated are sensitive to the scaling dimensions of the dual condensates. For all the $m^2$, the characteristic lengths diverge at the critical temperature in agreement with the Ginzburg-Landau theory. The Ginzburg-Landau parameter, obtained from these length scales indicates that the holographic superconductors can be type I or type II depending on the charge and the scaling dimensions of the dual condensates. For a fixed charge, there exists a critical scaling dimension, above which a holographic superconductor is type I, below which it becomes a type II.Comment: 24 pages 47 figure

Gender differences in motivation and perception of utility of the scholar spot

El principal objetivo del estudio es analizar las diferencias entre el nivel de autodeterminación y la satisfacción de las necesidades psicológicas básicas en función del género y su incidencia sobre la percepción de utilidad del deporte. Participaron en el estudio 1897 jóvenes jugadores de baloncesto, balonmano, fútbol y voleibol (1378 chicos y 519 chicas). Diferentes instrumentos fueron utilizados para medir las distintas variables abordadas en el estudio. Los resultados mostraron que los chicos presentan puntuaciones más altas en todos los tipos de motivación y que su sentimiento de competencia es más elevado que el de las chicas. Por otro lado, la motivación autodeterminada y la satisfacción de las necesidades conducen a percibir mayor utilidad del deporte en ambos génerosThe aim of the study was to analyze the differences between self-determination level and satisfaction of the three psychological needs with respect to gender and their influence on the perception of utility of the sport. The sample comprised 1897 basketball, handball, football and volleyball young players (1378 boys and 519 girls). Different measures were used to examine the differences between the variables contained in the study. Results showed that boys were more intrinsically and extrinsically motivated and showed less a motivation than girls, as well as their scored higher in competence than girls. However, both for boys and girls, self-determined motivation and psychological needs satisfaction led to a greater perception of utility of the spor