8,435 research outputs found

    Claytonia virginica L.

    Get PDF
    https://thekeep.eiu.edu/herbarium_specimens_byname/13494/thumbnail.jp

    Viola sororia Willd.

    Get PDF
    https://thekeep.eiu.edu/herbarium_specimens_byname/20578/thumbnail.jp

    Phonological Development in the Early Speech of an Indonesian-German Bilingual Child

    Get PDF
    Current research in bilingual children’s language development with one language dominant has shown that one linguistic system can affect the other. This is called Crosslinguistic Influence (CLI). This paper explores whether CLI is experienced by a bilingual child raised in two typologically distinct languages in terms of phonological development. It uses data from the study of a child simultaneously acquiring Indonesian and German between the ages of 12 months - 20 months, with Indonesian as the dominant language. The sound segments developed by the child showed universal tendencies, with the appearance of bilabials prior to alveolar sounds, followed by velar sounds. The sounds were produced mostly in the form of stops, nasals and glides. Three phonological processes were displayed by the child: substitution, assimilation and syllable structures. The front rounded vowel [ʏ], which exists in German but not in the Indonesian sound system, was systematically replaced by the palatal approximant [j]. This approximant exists in the Indonesian sound system but not in the German phonemic inventory. This provides evidence that, in terms of phonological development, the child experienced CLI, but only for certain sound transfers

    Timing properties of ULX pulsars: optically thick envelopes and outflows

    Get PDF
    It has recently been discovered that a fraction of ultra-luminous X-ray sources (ULXs) exhibit X-ray pulsations, and are therefore powered by super-Eddington accretion onto magnetized neutron stars (NSs). For typical ULX mass accretion rates (1019gs1\gtrsim 10^{19}\,{\rm g\,s^{-1}}), the inner parts of the accretion disc are expected to be in the supercritical regime, meaning that some material is lost in a wind launched from the disc surface, while the rest forms an optically thick envelope around the NS as it follows magnetic field lines from the inner disc radius to the magnetic poles of the star. The envelope hides the central object from a distant observer and defines key observational properties of ULX pulsars: their energy spectrum, polarization, and timing features. The optical thickness of the envelope is affected by the mass losses from the disc. We calculate the mass loss rate due to the wind in ULX pulsars, accounting for the NS magnetic field strength and advection processes in the disc. We argue that the detection of strong outflows from ULX pulsars can be considered evidence of a relatively weak dipole component of the NS magnetic field. We estimate the influence of mass losses on the optical thickness of the envelope and analyze how the envelope affects broadband aperiodic variability in ULXs. We show that brightness fluctuations at high Fourier frequencies can be strongly suppressed by multiple scatterings in the envelope and that the strength of suppression is determined by the mass accretion rate and geometrical size of the magnetosphere.Comment: 12 pages, 11 figures, accepted for publication in MNRA

    Trace element geochemistry of peridotites from the Izu-Bonin-Mariana Forearc, Leg 125

    No full text
    Trace element analyses (first-series transition elements, Ti, Rb, Sr, Zr, Y, Nb, and REE) were carried out on whole rocks and minerals from 10 peridotite samples from both Conical Seamount in the Mariana forearc and Torishima Forearc Seamount in the Izu-Bonin forearc using a combination of XRF, ID-MS, ICP-MS, and ion microprobe. The concentrations of incompatible trace elements are generally low, reflecting the highly residual nature of the peridotites and their low clinopyroxene content (n ratios in the range of 0.05-0.25; several samples show possible small positive Eu anomalies. LREE enrichment is common to both seamounts, although the peridotites from Conical Seamount have higher (La/Ce)n ratios on extended chondrite-normalized plots, in which both REEs and other trace elements are organized according to their incompatibility with respect to a harzburgitic mantle. Comparison with abyssal peridotite patterns suggests that the LREEs, Rb, Nb, Sr, Sm, and Eu are all enriched in the Leg 125 peridotites, but Ti and the HREEs exhibit no obvious enrichment. The peridotites also give positive anomalies for Zr and Sr relative to their neighboring REEs. Covariation diagrams based on clinopyroxene data show that Ti and the HREEs plot on an extension of an abyssal peridotite trend to more residual compositions. However, the LREEs, Rb, Sr, Sm, and Eu are displaced off this trend toward higher values, suggesting that these elements were introduced during an enrichment event. The axis of dispersion on these plots further suggests that enrichment took place during or after melting and thus was not a characteristic of the lithosphere before subduction. Compared with boninites sampled from the Izu-Bonin-Mariana forearc, the peridotites are significantly more enriched in LREEs. Modeling of the melting process indicates that if they represent the most depleted residues of the melting events that generated forearc boninites they must have experienced subsolidus enrichment in these elements, as well as in Rb, Sr, Zr, Nb, Sm, and Eu. The lack of any correlation with the degree of serpentinization suggests that low-temperature fluids were not the prime cause of enrichment. The enrichment in the high-field-strength elements also suggests that at least some of this enrichment may have involved melts rather than aqueous fluids. Moreover, the presence of the hydrous minerals magnesio-hornblende and tremolite and the common resorption of orthopyroxene indicate that this high-temperature peridotite-fluid interaction may have taken place in a water-rich environment in the forearc following the melting event that produced the boninites. The peridotites from Leg 125 may therefore contain a record of an important flux of elements into the mantle wedge during the initial formation of forearc lithosphere. Ophiolitic peridotites with these characteristics have not yet been reported, perhaps because the precise equivalents to the serpentinite seamounts have not been analyzed
    corecore