11,798 research outputs found

    The z=0.8596 Damped Lyman Alpha Absorbing Galaxy Toward PKS 0454+039

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    We present {\it Hubble Space Telescope} and ground--based data on the zabs=0.8596z_{abs}=0.8596 metal line absorption system along the line of sight to PKS 0454+0356. The system is a moderate redshift damped Lyman alpha system, with N(HI)=(5.7±0.3)×1020{\rm N(HI)}=(5.7\pm0.3)\times10^{20}~cm−2^{-2} as measured from the {\it Faint Object Spectrograph} spectrum. We also present ground--based images which we use to identify the galaxy which most probably gives rise to the damped system; the most likely candidate is relatively underluminous by QSO absorber standards (MB∼−19.0M_B \sim -19.0 for q0=0.5q_0=0.5 and H0=50H_0=50 \kms Mpc−1^{-1}), and lies ∼8.5h−1\sim 8.5h^{-1} kpc in projection from the QSO sightline. Ground--based measurements of Zn~II, Cr~II, and Fe~II absorption lines from this system allow us to infer abundances of [Zn/H]=−1.1-1.1, [Cr/H]=−1.2-1.2, and [Fe/H]=−1.2-1.2, indicating overall metallicity similar to damped systems at z>2z >2, and that the depletion of Cr and Fe onto dust grains may be even {\it less} important than in many of the high redshift systems of comparable metallicity. Limits previously placed on the 21-cm optical depth in the z=0.8596z=0.8596 system, together with our new N(H~I) measurement, suggest a very high spin temperature for the H~I, TS>>580T_S >> 580 K.Comment: changed uuencode header to produce .Z file so that unix uncompress command will work without modifying file nam

    Producing graphite with desired properties

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    Isotropic or anisotropic graphite is synthesized with precise control of particle size, distribution, and shape. The isotropic graphites are nearly perfectly isotropic, with thermal expansion coefficients two or three times those of ordinary graphites. The anisotropic graphites approach the anisotropy of pyrolytic graphite

    Structure of Micro-instabilities in Tokamak Plasmas: Stiff Transport or Plasma Eruptions?

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    Solutions to a model 2D eigenmode equation describing micro-instabilities in tokamak plasmas are presented that demonstrate a sensitivity of the mode structure and stability to plasma profiles. In narrow regions of parameter space, with special plasma profiles, a maximally unstable mode is found that balloons on the outboard side of the tokamak. This corresponds to the conventional picture of a ballooning mode. However, for most profiles this mode cannot exist and instead a more stable mode is found that balloons closer to the top or bottom of the plasma. Good quantitative agreement with a 1D ballooning analysis is found provided the constraints associated with higher order profile effects, often neglected, are taken into account. A sudden transition from this general mode to the more unstable ballooning mode can occur for a critical flow shear, providing a candidate model for why some experiments observe small plasma eruptions (Edge Localised Modes, or ELMs) in place of large Type I ELMs.Comment: 11 pages, 3 figure

    Fall prevention in the community: what older people say they need

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    Original article can be found at: http://www.bjcn.co.uk/ Copyright MA HealthcareUptake of and adherence to fall prevention interventions is often poor and we know little about how older people’s perceptions of and beliefs about fall prevention interventions affect uptake. This study aimed to explore older people’s perceptions of the facilitators and barriers to participation in fall prevention interventions. We undertook a qualitative study with older people who had taken part in, declined to participate or adhere to fall prevention interventions using semi-structured interviews (n=65), and 17 focus groups (n=122) with older people (including 32 South Asian and 30 Chinese older people) in primary and community care settings in the South of England. A number of factors acted as either barriers or facilitators to uptake of interventions. Older people also made recommendations for improving access to interventions. Community nurses are ideally placed to screen older people, identify those at risk of falling and refer them to appropriate interventions as well as providing health promotion and education.Peer reviewe

    Tourism and the smartphone app: capabilities, emerging practice and scope in the travel domain.

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    Based on its advanced computing capabilities and ubiquity, the smartphone has rapidly been adopted as a tourism travel tool.With a growing number of users and a wide varietyof applications emerging, the smartphone is fundamentally altering our current use and understanding of the transport network and tourism travel. Based on a review of smartphone apps, this article evaluates the current functionalities used in the domestic tourism travel domain and highlights where the next major developments lie. Then, at a more conceptual level, the article analyses how the smartphone mediates tourism travel and the role it might play in more collaborative and dynamic travel decisions to facilitate sustainable travel. Some emerging research challenges are discussed

    Tests of star formation metrics in the low metallicity galaxy NGC 5253 using ALMA observations of H30α\alpha line emission

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    We use Atacama Large Millimeter/submillimeter Array (ALMA) observations of H30α\alpha (231.90 GHz) emission from the low metallicity dwarf galaxy NGC 5253 to measure the star formation rate (SFR) within the galaxy and to test the reliability of SFRs derived from other commonly-used metrics. The H30α\alpha emission, which originates mainly from the central starburst, yields a photoionizing photon production rate of (1.9±\pm0.3)×\times1052^{52} s−1^{-1} and an SFR of 0.087±\pm0.013 M⊙_\odot yr−1^{-1} based on conversions that account for the low metallicity of the galaxy and for stellar rotation. Among the other star formation metrics we examined, the SFR calculated from the total infrared flux was statistically equivalent to the values from the H30α\alpha data. The SFR based on previously-published versions of the Hα\alpha flux that were extinction corrected using Paα\alpha and Paβ\beta lines were lower than but also statistically similar to the H30α\alpha value. The mid-infrared (22 μ\mum) flux density and the composite star formation tracer based on Hα\alpha and mid-infrared emission give SFRs that were significantly higher because the dust emission appears unusually hot compared to typical spiral galaxies. Conversely, the 70 and 160 μ\mum flux densities yielded SFR lower than the H30α\alpha value, although the SFRs from the 70 μ\mum and H30α\alpha data were within 1-2σ\sigma of each other. While further analysis on a broader range of galaxies are needed, these results are instructive of the best and worst methods to use when measuring SFR in low metallicity dwarf galaxies like NGC 5253.Comment: 14 pages, 5 figures, accepted for publication in MNRA

    Model Looks, Motives, and Affective Outcomes

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    Highly attractive models are intended to impact psychologically on message receivers and improve awareness, expectations, attitudes, beliefs, and advertising effectiveness; however, benefits accrue in only particular situations. This study examines how advertising triggers affect when comparison motive is paired with a particular model beauty type. Qualitative work preceded empirical study, which involved use of three types of model beauty (classic, sexual, and cute), two comparison motives (self-evaluation headline and self-improvement headline), and two product contexts (problem-solving and enhancement). Female university students (N = 1,170) were surveyed with findings indicating that viewers do react differently depending on the beauty type, with evidence of an interaction between beauty type and comparison motive

    Deep Halpha imagery of the Eridanus shells

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    A deep \ha image of interlocking filamentary arcs of nebulosity has been obtained with a wide-field (≈\approx 30\degree diameter) narrow-band filter camera combined with a CCD as a detector. The resultant mosaic of images, extending to a galactic latitude of 65o^{o}, has been corrected for field distortions and had galactic coordinates superimposed on it to permit accurate correlations with the most recent H{\sc i} (21 cm), X-ray (0.75 kev) and FIR (IRAS 100 μ\mum) maps. Furthermore, an upper limit of 0.13 arcsec/yr to the expansion proper motion of the primary 25\degree long nebulous arc has been obtained by comparing a recent \ha image obtained with the San Pedro Martir telescope of its filamentary edge with that on a POSS E plate obtained in 1951. It is concluded that these filamentary arcs are the superimposed images of separate shells (driven by supernova explosions and/or stellar winds) rather than the edges of a single `superbubble' stretching from Barnard's Arc (and the Orion Nebula) to these high galactic latitudes. The proper motion measurement argues against the primary \ha emitting arc being associated with the giant radio loop (Loop 2) except in extraordinary circumstances.Comment: 9 pages, 5 figures, accepted for MNRAS publicatio
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