8,318 research outputs found

    Fine-Structure FeII* Emission and Resonant MgII Emission in z = 1 Star-Forming Galaxies

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    We present a study of the prevalence, strength, and kinematics of ultraviolet FeII and MgII emission lines in 212 star-forming galaxies at z = 1 selected from the DEEP2 survey. We find FeII* emission in composite spectra assembled on the basis of different galaxy properties, indicating that FeII* emission is prevalent at z = 1. In these composites, FeII* emission is observed at roughly the systemic velocity. At z = 1, we find that the strength of FeII* emission is most strongly modulated by dust attenuation, and is additionally correlated with redshift, star-formation rate, and [OII] equivalent width, such that systems at higher redshifts with lower dust levels, lower star-formation rates, and larger [OII] equivalent widths show stronger FeII* emission. We detect MgII emission in at least 15% of the individual spectra and we find that objects showing stronger MgII emission have higher specific star-formation rates, smaller [OII] linewidths, larger [OII] equivalent widths, lower dust attenuations, and lower stellar masses than the sample as a whole. MgII emission strength exhibits the strongest correlation with specific star-formation rate, although we find evidence that dust attenuation and stellar mass also play roles in the regulation of MgII emission. Future integral field unit observations of the spatial extent of FeII* and MgII emission in galaxies with high specific star-formation rates, low dust attenuations, and low stellar masses will be important for probing the morphology of circumgalactic gas.Comment: 29 pages, 22 figures, 2 tables; accepted to Ap

    Deconstruction and Gauge Theories in AdS_5

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    On a slice of AdS_5, despite having a dimensionful coupling, gauge theories can exhibit logarithmic dependence on scale. In this paper, we utilize deconstruction to analyze the scaling behavior of the theory, both above and below the AdS curvature scale, and shed light on position-dependent regularizations of the theory. We comment on applications to geometries other than AdS.Comment: 15 pages, 1 figur

    The DEEP2 Redshift Survey: Lyman Alpha Emitters in the Spectroscopic Database

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    We present the first results of a search for Lyman-alpha emitters (LAEs) in the DEEP2 spectroscopic database that uses a search technique that is different from but complementary to traditional narrowband imaging surveys. We have visually inspected ~20% of the available DEEP2 spectroscopic data and have found nine high-quality LAEs with clearly asymmetric line profiles and an additional ten objects of lower quality, some of which may also be LAEs. Our survey is most sensitive to LAEs at z=4.4-4.9 and that is indeed where all but one of our high-quality objects are found. We find the number density of our spectroscopically-discovered LAEs to be consistent with those found in narrowband imaging searches. The combined, averaged spectrum of our nine high-quality objects is well fit by a two-component model, with a second, lower-amplitude component redshifted by ~420 km/s with respect to the primary Lyman-alpha line, consistent with large-scale outflows from these objects. We conclude by discussing the advantages and future prospects of blank-sky spectroscopic surveys for high-z LAEs.Comment: Accepted for publication in Ap

    What's the point of knowing how?

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    Why is it useful to talk and think about knowledge-how? Using Edward Craig’s discussion of the function of the concepts of knowledge and knowledge-how as a jumping off point, this paper argues that considering this question can offer us new angles on the debate about knowledge-how. We consider two candidate functions for the concept of knowledge-how: pooling capacities, and mutual reliance. Craig makes the case for pooling capacities, which connects knowledge-how to our need to pool practical capacities. I argue that the evidence is much more equivocal. My suggested diagnosis is that the concept of knowledge-how plays both functions, meaning that the concept of knowledge-how is inconsistent, and that the debate about knowledge-how is at least partly a metalinguistic negotiation. In closing, I suggest a way to revise the philosophical concept of knowledge how

    Higher-order corrections to the short-pulse equation

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    Using renormalization group techniques, we derive an extended short- pulse equation as approximation to a nonlinear wave equation. We investigate the new equation numerically and show that the new equation captures efficiently higher- order effects on pulse propagation in cubic nonlinear media. We illustrate our findings using one- and two-soliton solutions of the first-order short-pulse equation as initial conditions in the nonlinear wave equation

    Capture Velocity for a Magneto-Optical Trap in a Broad Range of Light Intensity

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    In a recent paper, we have used the dark-spot Zeeman tuned slowing technique [Phys. Rev. A 62, 013404-1, (2000)] to measure the capture velocity as a function of laser intensity for a sodium magneto optical trap. Due to technical limitation we explored only the low light intensity regime, from 0 to 27 mW/cm^2. Now we complement that work measuring the capture velocity in a broader range of light intensities (from 0 to 400 mW/cm^2). New features, observed in this range, are important to understant the escape velocity behavior, which has been intensively used in the interpretation of cold collisions. In particular, we show in this brief report that the capture velocity has a maximum as function of the trap laser intensity, which would imply a minimum in the trap loss rates.Comment: 2 pages, 2 figure

    Broken-symmetry-adapted Green function theory of condensed matter systems:towards a vector spin-density-functional theory

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    The group theory framework developed by Fukutome for a systematic analysis of the various broken symmetry types of Hartree-Fock solutions exhibiting spin structures is here extended to the general many body context using spinor-Green function formalism for describing magnetic systems. Consequences of this theory are discussed for examining the magnetism of itinerant electrons in nanometric systems of current interest as well as bulk systems where a vector spin-density form is required, by specializing our work to spin-density-functional formalism. We also formulate the linear response theory for such a system and compare and contrast them with the recent results obtained for localized electron systems. The various phenomenological treatments of itinerant magnetic systems are here unified in this group-theoretical description.Comment: 17 page

    Biomarkers of Tuberculosis Severity and Treatment Effect: A Directed Screen of 70 Host Markers in a Randomized Clinical Trial.

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    More efficacious treatment regimens are needed for tuberculosis, however, drug development is impeded by a lack of reliable biomarkers of disease severity and of treatment effect. We conducted a directed screen of host biomarkers in participants enrolled in a tuberculosis clinical trial to address this need. Serum samples from 319 protocol-correct, culture-confirmed pulmonary tuberculosis patients treated under direct observation as part of an international, phase 2 trial were screened for 70 markers of infection, inflammation, and metabolism. Biomarker assays were specifically developed for this study and quantified using a novel, multiplexed electrochemiluminescence assay. We evaluated the association of biomarkers with baseline characteristics, as well as with detailed microbiologic data, using Bonferroni-adjusted, linear regression models. Across numerous analyses, seven proteins, SAA1, PCT, IL-1β, IL-6, CRP, PTX-3 and MMP-8, showed recurring strong associations with markers of baseline disease severity, smear grade and cavitation; were strongly modulated by tuberculosis treatment; and had responses that were greater for patients who culture-converted at 8weeks. With treatment, all proteins decreased, except for osteocalcin, MCP-1 and MCP-4, which significantly increased. Several previously reported putative tuberculosis-associated biomarkers (HOMX1, neopterin, and cathelicidin) were not significantly associated with treatment response. In conclusion, across a geographically diverse and large population of tuberculosis patients enrolled in a clinical trial, several previously reported putative biomarkers were not significantly associated with treatment response, however, seven proteins had recurring strong associations with baseline radiographic and microbiologic measures of disease severity, as well as with early treatment response, deserving additional study

    Myelin Oligodendrocyte Glycoprotein–specific T Cell Receptor Transgenic Mice Develop Spontaneous Autoimmune Optic Neuritis

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    Multiple sclerosis (MS) is considered to be an autoimmune disease of the central nervous system (CNS) that in many patients first presents clinically as optic neuritis. The relationship of optic neuritis to MS is not well understood. We have generated novel T cell receptor (TCR) transgenic mice specific for myelin oligodendrocyte glycoprotein (MOG). MOG-specific transgenic T cells are not deleted nor tolerized and are functionally competent. A large proportion (>30%) of MOG-specific TCR transgenic mice spontaneously develop isolated optic neuritis without any clinical nor histological evidence of experimental autoimmune encephalomyelitis (EAE). Optic neuritis without EAE could also be induced in these mice by sensitization with suboptimal doses of MOG. The predilection of these mice to develop optic neuritis is associated with higher expression of MOG in the optic nerve than in the spinal cord. These results demonstrate that clinical manifestations of CNS autoimmune disease will vary depending on the identity of the target autoantigen and that MOG-specific T cell responses are involved in the genesis of isolated optic neuritis
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