1,747 research outputs found

    Bjerrum pairing correlations at charged interfaces

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    Electrostatic correlations play a fundamental role in aqueous solutions. In this letter, we identify transverse and lateral correlations as two mutually exclusive regimes. We show that the transverse regime leads to binding by generalization of Bjerrum pair formation theory, yielding binding constants from first-principle statistical-mechanical calculations. We compare our theoretical predictions with experiments on charged membranes and Langmuir monolayers and find good agreement. We contrast our approach with existing theories in the strong-coupling limit and on charged modulated interfaces, and discuss different scenarios that lead to charge reversal and equal-sign attraction by macro-ions.Comment: 7 pages, 4 figure

    Building the Galactic halo from globular clusters: evidence from chemically unusual red giants

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    We present a spectroscopic search for halo field stars that originally formed in globular clusters. Using moderate-resolution SDSS-III/SEGUE-2 spectra of 561 red giants with typical halo metallicities (-1.8 < [Fe/H] < -1.0), we identify 16 stars, 3% of the sample, with CN and CH bandstrength behavior indicating depleted carbon and enhanced nitrogen abundances relative to the rest of the data set. Since globular clusters are the only environment known in which stars form with this pattern of atypical light-element abundances, we claim that these stars are second-generation globular cluster stars that have been lost to the halo field via normal cluster mass-loss processes. Extrapolating from theoretical models of two-generation globular cluster formation, this result suggests that globular clusters contributed significant numbers of stars to the construction of the Galactic halo: we calculate that a minimum of 17% of the present-day mass of the stellar halo was originally formed in globular clusters. The ratio of CN-strong to CN-normal stars drops with Galactocentric distance, suggesting that the inner-halo population may be the primary repository of these stars.Comment: 9 pages including 8 figures, A&A accepte

    From the Field | Field Notes From Jail: How Incarceration and Homelessness Impact Women’s Health

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    A multi-disciplinary team explored the journey they took with female inmates to develop a collaborative research strategy among the university, community organizations, and the correctional facility. The team consisted of academic researchers, inner city physicians, social workers, nurses, Aboriginal art therapists, Aboriginal cultural consultants, correctional healthcare administrators, and inner city chaplains from non-profit organizations. This paper describes how the team reflected on the journey to determine the impact of incarceration and/or homelessness on the health of female inmates, as they (the team) patiently waited for ethics boards and administrative approval; negotiated correctional center lockdowns; and became exhausted from trying to reconnect with women who were released from incarceration. The researchers discovered what kept them passionate about helping female inmates work through multiple hurdles that included housing, child custody, employment, probation appointments, and counseling. These administrative and operational challenges strengthened the team’s resolve to support these vulnerable women

    Weighted norm inequalities, off-diagonal estimates and elliptic operators. Part IV: Riesz transforms on manifolds and weights

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    This is the fourth article of our series. Here, we study weighted norm inequalities for the Riesz transform of the Laplace-Beltrami operator on Riemannian manifolds and of subelliptic sum of squares on Lie groups, under the doubling volume property and Gaussian upper bounds.Comment: 12 pages. Fourth of 4 papers. Important revision: improvement of main result by eliminating use of Poincar\'e inequalities replaced by the weaker Gaussian keat kernel bound

    Properties of the ω\omega Meson at Finite Temperature and Density

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    The mass shift, width broadening, and spectral density for the ω\omega meson in a heat bath of nucleons and pions is calculated using a general formula which relates the self-energy to the forward scattering amplitude. We use experimental data to saturate the scattering amplitude at low energies with resonances and include a background Pomeron term, while at high energies a Regge parameterization is used. The peak of the spectral density is little shifted from its vacuum position, but the width is considerably increased due to collisional broadening. At normal nuclear matter density and a temperature of 150 MeV the spectral density of the ω\omega meson has a width of 140 MeV. Zero temperature nuclear matter is also discussed.Comment: 5 pages revtex4, 3 figur

    hVH-5: A Protein Tyrosine Phosphatase Abundant in Brain that Inactivates Mitogen-Activated Protein Kinase

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    A novel protein tyrosine phosphatase [ h omologue of v accinia virus H 1 phosphatase gene clone 5 (hVH-5)] was cloned; it shared sequence similarity with a subset of protein tyrosine phosphatases that regulate mitogen-activated protein kinase. The catalytic region of hVH-5 was expressed as a fusion protein and was shown to hydrolyze p -nitrophenylphosphate and inactivate mitogen-activated protein kinase, thus proving that hVH-5 possessed phosphatase activity. A unique proline-rich region distinguished hVH-5 from other closely related protein tyrosine phosphatases. Another feature that distinguished hVH-5 from related phosphatases was that hVH-5 was expressed predominantly in the adult brain, heart, and skeletal muscle. In addition, in situ hybridization histochemistry of mouse embryo revealed high levels of expression and a wide distribution in the central and peripheral nervous system. Some specific areas of abundant hVH-5 expression included the olfactory bulb, retina, layers of the cerebral cortex, and cranial and spinal ganglia. hVH-5 was induced in PC12 cells upon nerve growth factor and insulin treatment in a manner characteristic of an immediate-early gene, suggesting a possible role in the signal transduction cascade.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65883/1/j.1471-4159.1995.65041823.x.pd

    ‘It stays with you’: multiple evocative representations of dance and future possibilities for studies in sport and physical cultures

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    This article considers the integration of arts-based representations via poetic narratives together with artistic representation on dancing embodiment so as to continue an engagement with debates regarding multiple forms/representations. Like poetry, visual images are unique and can evoke particular kinds of emotional and visceral responses, meaning that alternative representational forms can resonate in different and powerful ways. In the article, we draw on grandparent-grandchild interactions, narrative poetry, and artistic representations of dance in order to illustrate how arts-based methods might synergise to offer new ways of ‘knowing’ and ‘seeing’. The expansion of the visual arts into interdisciplinary methodological innovations is a relatively new, and sometimes contentious approach, in studies of sport and exercise. We raise concerns regarding the future for more arts-based research in the light of an ever-changing landscape of a neoliberal university culture that demands high productivity in reductionist terms of what counts as ‘output’, often within very restricted time-frames. Heeding feminist calls for ‘slow academies’ that attempt to ‘change’ time collectively, and challenge the demands of a fast-paced audit culture, we consider why it is worth enabling creative and arts-based methods to continue to develop and flourish in studies of sport, exercise and health, despite the mounting pressures to ‘perform’

    A Survey of CN and CH Variations in Galactic Globular Clusters from SDSS Spectroscopy

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    We present a homogeneous survey of the CN and CH bandstrengths in eight Galactic globular clusters observed during the course of the Sloan Extension for Galactic Understanding and Exploration (SEGUE) sub-survey of the SDSS. We confirm the existence of a bimodal CN distribution among RGB stars in all of the clusters with metallicity greater than [Fe/H] = -1.7; the lowest metallicity cluster with an observed CN bimodality is M53, with [Fe/H] ~ -2.1. There is also some evidence for individual CN groups on the subgiant branches of M92, M2, and M13, and on the red giant branches of M92 and NGC 5053. Finally, we quantify the correlation between overall cluster metallicity and the slope of the CN bandstrength-luminosity plot as a means of further demonstrating the level of CN-enrichment in cluster giants. Our results agree well with previous studies reported in the literature.Comment: AJ submitted; 80 pages, 22 figure
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