28 research outputs found
KIC 5950759: a high-amplitude δ Sct star with amplitude and frequency modulation near the terminal age main sequence
Amongst the intermediate mass pulsating stars known as δ Sct stars is a subset of high amplitude and predominantly radial-mode pulsators known as high-amplitude δ Sct (HADS) stars. From more than 2000 δ Sct stars observed by the Kepler space mission, only two HADS stars were detected.We investigate the more perplexing of these two HADS stars, KIC 5950759.
We study its variability using ground- and space-based photometry, determine its atmospheric parameters from spectroscopy and perform asteroseismic modelling to constrain its mass and evolutionary stage. From spectroscopy, we find that KIC 5950759 is a metal-poor star, which is in agreement with the inferred metallicity needed to reproduce its pulsation mode frequencies from non-adiabatic pulsation models. Furthermore, we combine ground-based WASP and Kepler space photometry, and measure a linear change in period of order P /P ˙ ' 10−6 yr−1 for both the fundamental and first overtone radial modes across a time base of several years, which is at least two orders of magnitude larger than predicted by evolution models, and is the largest measured period change in a δ Sct star to date. Our analysis indicates that KIC 5950759 is a metal-poor HADS star near the short-lived contraction phase and the terminal-age main sequence, with its sub-solar metallicity making it a candidate SX Phe star. KIC 5950759 is a unique object amongst the thousands of known δ Sct stars and warrants further study to ascertain why its pulsation modes are evolving remarkably faster than predicted by stellar evolution
TESS Cycle 1 observations of roAp stars with 2-min cadence data
We present the results of a systematic search for new rapidly oscillating Ap (roAp) stars using the 2-min cadence data collected by the Transiting Exoplanet Survey Satellite (TESS) during its Cycle 1 observations. We identify 12 new roAp stars. Amongst these stars we discover the roAp star with the longest pulsation period, another with the shortest rotation period, and six with multiperiodic variability. In addition to these new roAp stars, we present an analysis of 44 known roAp stars observed by TESS during Cycle 1, providing the first high-precision and homogeneous sample of a significant fraction of the known roAp stars. The TESS observations have shown that almost 60 per cent (33) of our sample of stars are multiperiodic, providing excellent cases to test models of roAp pulsations, and from which the most rewarding asteroseismic results can be gleaned. We report four cases of the occurrence of rotationally split frequency multiplets that imply different mode geometries for the same degree modes in the same star. This provides a conundrum in applying the oblique pulsator model to the roAp stars. Finally, we report the discovery of non-linear mode interactions in Cir (TIC 402546736, HD 128898) around the harmonic of the principal mode -- this is only the second case of such a phenomenon...
Paraquat poisoning in dogs and cats—differences between accidental and malicious poisoning
Population Development of the DinoflagellatesCeratium furca andCeratium fusus during Spring and Early Summer in Iwa Harbor, Sagami Bay, Japan
Propagação vegetativa de Platanus AcerIfolia Ait.: (I) efeito de tipos fisiológicos das estacas e épocas de coleta no enraizamento de estacas Vegetative propagation of Platanus AcerIfolia Ait.: (I) effect of physiological types of cuttings and times of the cuttings collection on rooting
O objetivo desse trabalho foi avaliar os efeitos do tipo fisiológico da estaca e da época de coleta no enraizamento de estacas de Platanus acerifolia Ait. Os tratamentos consistiram de uma combinação bifatorial (4 x 4), representados por quatro tipos fisiológicos de estacas de ramos ("de ano", "do ano" basal, "do ano" mediana e "do ano" basal fina) e quatro épocas de coleta (setembro/95, janeiro/96, março/96 e julho/96). A estaquia foi realizada em vasos contendo como substrato uma mistura de areia média e casca de arroz carbonizada (1:1, v/v), ambas lavadas. O experimento foi conduzido por 110 dias em casa de vegetação com sistema de microaspersão intermitente. A melhor época de coleta das estacas para o enraizamento é em julho e as estacas de ramos "do ano" basais apresentam o maior potencial de enraizamento.<br>The aim of this work was to evaluate the effect of the physiological type of the cutting on rooting of Platanus acerifolia Ait. cuttings collected at different times. The treatments followed a 4 x 4 factorial scheme, involving four physiological types of the cuttings (hardwood, basal semi-herbaceous, middle semi-herbaceous, and thin basal semi-herbaceous), and four different times of the cuttings collection (September/95, January/96, March/96, and July/96). The cuttings were rooted in pots containing as substrate a mixture of medium sand + carbonised rice husk, 1:1 v/v, both washed. The experiment was conducted during 110 days under intermittent artificial mist conditions. The results indicate that the best time to collect cuttings to get rooting is in July, and basal semi-herbaceous cutting shows the best percentage on rooting
To the Statistics of the Jewry of the Kingdom of Serbs, Croats and Slovenes
U tekstu se daju sažeti opisi dve cionističke organizacije u Kraljevini SHS koje su delovale kao ogranci Svetske cionističke organizacije. Svrha formiranja ovih organizacija bila je da se Jevrejima iz celog sveta omogući povratak u njihovu domovinu - Erec Izrael odnosno Palestinu. Balfurovom deklaracijom iz 1917. godine godine Velika Britanija dala je podršku za osnivanje jevrejske države na području Palestine a zaključkom Lige naroda ova podrška postala je i i formalna. Podrška jevrejstva u Kraljevini SHS ovom pokretu odnosila se na prikupljanje priloga, učenje hebrejskog jezika, promovisanje nacionalnih vrednosti, osnivanje sindikalnih i radničkih organizacija. U ovom pregledu predstavljeni su Savez Cionista u Kraljevini SHS i Hapoel hacair Jugoslavije. Kao centralno glasilo jugoslavenskih Jevreja i cionističke misli naveden je i časopis "Židov" osnovan 1916. godine.The text gives concise descriptions of two Zionist organizations in the Kingdom of Serbs, Croats and Slovenes that acted as branches of the World Zionist organization. The purpose of forming these organizations was to enable Jews from all over the world to return to their homeland - Eretz Israel or Palestine. With the Balfour Declaration of 1917, Great Britain gave support for the establishment of a Jewish state on the territory of Palestine, and with the conclusion of the League of Nations, this support became formal. The support of Judaism in the Kingdom of Serbs, Croats and Slovenes to this movement referred to collecting donations, learning the Hebrew language, promoting national values, and founding trade unions and workers' organizations. In this review, the Federation of Zionists in the Kingdom of Serbs, Croats and Slovenes and Hapoel Hacair of Yugoslavia are presented. The magazine "Židov" (Jew), founded in 1916, is also mentioned as the central newspaper of Yugoslav Jews and Zionist thought