Polarization of Broad Absorption Line QSOs I. A Spectropolarimetric Atlas

We present a spectropolarimetric survey of 36 broad absorption line quasi-stellar objects (BAL QSOs). The continuum, absorption trough, and emission line polarization of BAL QSOs yield clues about their structure. We confirm that BAL QSOs are in general more highly polarized than non-BAL QSOs, consistent with a more equatorial viewing direction for the former than the latter. We have identified two new highly-polarized QSOs in our sample (1232+1325 and 1333+2840). The polarization rises weakly to the blue in most objects, perhaps due to scattering and absorption by dust particles. We find that a polarization increase in the BAL troughs is a general property of polarized BAL QSOs, indicating an excess of scattered light relative to direct light, and consistent with the unification of BAL QSOs and non-BAL QSOs. We have also discovered evidence of resonantly scattered photons in the red wing of the C IV broad emission lines of a few objects. In most cases, the broad emission lines have lower polarization and a different position angle than the continuum. The polarization characteristics of low-ionization BAL QSOs are similar to those of high-ionization BAL QSOs, suggesting a similar BAL wind geometry.Comment: 39 pages, 6 figures (20 .gif files), accepted for publication in The Astrophysical Journal Supplement

The masses of the millisecond pulsar J1012+5307 and its white-dwarf companion

We report on spectroscopy of the white-dwarf companion of the millisecond radio pulsar PSR J1012+5307. We find strong Balmer absorption lines, as would be expected for a cool DA white dwarf. The profiles are much narrower than usual, however, and lines are seen up to H12, indicating that the companion has a low gravity and hence a low mass. This is consistent with the expectation---based on evolutionary considerations and on the mass function---that it is a low-mass white dwarf with a helium core. By comparing the spectra to model atmospheres, we derive an effective temperature $T_{\rm{}eff}=8550\pm25\,$K and a surface gravity $\log{}g=6.75\pm0.07$ (cgs units). Using the Hamada-Salpeter mass-radius relation for helium white dwarfs, with an approximate correction for finite-temperature effects, we infer a mass \mwd=0.16\pm0.02\,\msun. This is the lowest mass among all spectroscopically identified white dwarfs. We determine radial velocities from our spectra, and find a radial-velocity amplitude of 280\pm15\,\kms. With the pulsar's radial-velocity amplitude, the mass ratio \mpsr/\mwd=13.3\pm0.7. From all constraints, we find that with 95\% confidence 1.5<\mpsr/\msun<3.2.Comment: 6 pages of text and figures. Refereed version, resubmitted to ApJL. Needs aas2pp4.sty, epsf.st

Activation pathway to amino acid adducts

Funding: This work was supported in part by Fundação para a Ciência e a Tecnologia (FCT), Portugal (PTDC/QUI-QUI/113910/2009, RECI/QEQ-MED/0330/2012, UID/QUI/00100/2013 and IF/ 01091/2013/CP1163/CT0001), and by Interagency Agreement Y1ES1027 between the National Center for Toxicological Research/Food and Drug Administration and the National Institute of Environmental Health Sciences/National Toxicology Program. The opinions expressed in this paper do not necessarily represent those of the U.S. Food and Drug Administration. RW, ALG, ILM and SGH thank FCT for postdoctoral and doctoral fellowships (SFRH/BPD/70953/2010, SFRH/BD/72301/2010, SFRH/BD/75426/2010 and SFRH/BD/ 80690/2011, respectively). AMM also acknowledges Programa Operacional Potencial Humano from FCT and the European Social Fund (IF/01091/2013), and the LRI Innovative Science Award. We thank the Portuguese NMR and MS networks (IST nodes) for providing access to the facilities.Nevirapine (NVP) is the non-nucleoside HIV-1 reverse transcriptase inhibitor most commonly used in developing countries, both as a component of combined antiretroviral therapy and to prevent mother-to-child transmission of the virus; however, severe hepatotoxicity and serious adverse cutaneous effects raise concerns about its safety. NVP metabolism yields several phenolic derivatives conceivably capable of undergoing further metabolic oxidation to electrophilic quinoid derivatives prone to react with bionucleophiles and initiate toxic responses. We investigated the ability of two phenolic NVP metabolites, 2-hydroxy-NVP and 3-hydroxy-NVP, to undergo oxidation and subsequent reaction with bionucleophiles. Both metabolites yielded the same ring-contraction product upon oxidation with Frémy's salt in aqueous medium. This is consistent with the formation of a 2,3-NVP-quinone intermediate, which upon stabilization by reduction was fully characterized by mass spectrometry and nuclear magnetic resonance spectroscopy. Additionally, we established that the oxidative activation of 2-hydroxy-NVP involved the transient formation of both the quinone and a quinone-imine, whereas 3-hydroxy-NVP was selectively converted into 2,3-NVP-quinone. The oxidations of 2-hydroxy-NVP and 3-hydroxy-NVP in the presence of the model amino acids ethyl valinate (to mimic the highly reactive N-terminal valine of hemoglobin) and N-acetylcysteine were also investigated. Ethyl valinate reacted with both 2,3-NVP-quinone and NVP-quinone-imine, yielding covalent adducts. By contrast, neither 2,3-NVP-quinone nor NVP-derived quinone-imine reacted with N-acetylcysteine. The product profile observed upon Frémy's salt oxidation of 2-hydroxy-NVP in the presence of ethyl valinate was replicated with myeloperoxidase-mediated oxidation. Additionally, tyrosinase-mediated oxidations selectively yielded 2,3-NVP-quinone-derived products, while quinone-imine-derived products were obtained upon lactoperoxidase catalysis. These observations suggest that the metabolic conversion of phenolic NVP metabolites into quinoid electrophiles is biologically plausible. Moreover, the lack of reaction with sulfhydryl groups might hamper the in vivo detoxification of NVP-derived quinone and quinone-imine metabolites via glutathione conjugation. As a result, these metabolites could be available for reaction with nitrogen-based bionucleophiles (e.g., lysine residues of proteins) ultimately eliciting toxic events.publishersversionpublishe

Deviations from the Local Hubble Flow. I. The Tip of the Red Giant Branch as a Distance Indicator

The properties of the velocity field in the local volume (cz < 550 km/s) have been difficult to constrain due to a lack of a consistent set of galaxy distances. The sparse observations available to date suggest a remarkably quiet flow, with little deviation from a pure Hubble law. However, velocity field models based on the distribution of galaxies in the 1.2 Jy IRAS redshift survey, predict a quadrupolar flow pattern locally with strong infall at the poles of the local Supergalactic plane. We probe this velocity field and begin to establish a consistent set of galactic distances. We have obtained images of nearby galaxies in the I and V band from the W.M. Keck Observatory and in F814W and F555W filters from the Hubble Space Telescope. Where these galaxies are well resolved into stars we may use the Tip of the Red Giant Branch (TRGB) as a distance indicator. Using a maximum likelihood analysis to quantitatively measure the I magnitude of the TRGB we determine precise distances to seven nearby galaxies: Leo I, Sextans B, NGC 1313, NGC 3109, UGC 03755, UGC 06456, and UGC 07577.Comment: AJ in Press, 54 pages, 30 figures, typos corrected, references added, postscript version with high resolution figures available at ftp://deep.berkeley.edu/pub/trgb/trgb.p

THE DATA REDUCTION PIPELINE FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, explores the stellar populations of the Milky Way using the Sloan 2.5-m telescope linked to a high resolution (R ~ 22,500), near-infrared (1.51–1.70 µm) spectrograph with 300 optical fibers. For over 150,000 predominantly red giant branch stars that APOGEE targeted across the Galactic bulge, disks and halo, the collected high signal-to-noise ratio (>100 per half-resolution element) spectra provide accurate (~0.1 km s-1) RVs, stellar atmospheric parameters, and precise (lesssim0.1 dex) chemical abundances for about 15 chemical species. Here we describe the basic APOGEE data reduction software that reduces multiple 3D raw data cubes into calibrated, well-sampled, combined 1D spectra, as implemented for the SDSS-III/APOGEE data releases (DR10, DR11 and DR12). The processing of the near-IR spectral data of APOGEE presents some challenges for reduction, including automated sky subtraction and telluric correction over a 3°-diameter field and the combination of spectrally dithered spectra. We also discuss areas for future improvement

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs

We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~ 10^5 red giant stars that systematically sampled all Milky Way populations (bulge, disk, and halo) to study the Galaxy's chemical and kinematical history. It was part of the Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014 using the 2.5 m Sloan Foundation Telescope at Apache Point Observatory, New Mexico. The APOGEE-2 survey is now using the spectrograph as part of SDSS-IV, as well as a second spectrograph, a close copy of the first, operating at the 2.5 m du Pont Telescope at Las Campanas Observatory in Chile. Although several fiber-fed, multi-object, high resolution spectrographs have been built for visual wavelength spectroscopy, the APOGEE spectrograph is one of the first such instruments built for observations in the near-infrared. The instrument's successful development was enabled by several key innovations, including a "gang connector" to allow simultaneous connections of 300 fibers; hermetically sealed feedthroughs to allow fibers to pass through the cryostat wall continuously; the first cryogenically deployed mosaic volume phase holographic grating; and a large refractive camera that includes mono-crystalline silicon and fused silica elements with diameters as large as ~ 400 mm. This paper contains a comprehensive description of all aspects of the instrument including the fiber system, optics and opto-mechanics, detector arrays, mechanics and cryogenics, instrument control, calibration system, optical performance and stability, lessons learned, and design changes for the second instrument.Comment: 81 pages, 67 figures, PASP, accepte

The Cosmic Origins Spectrograph

The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy

"The contribution of chronic diseases to the prevalence of dependence among older people in Latin America, China and India: a 10/66 Dementia Research Group population-based survey"

<p>Abstract</p> <p>Background</p> <p>The number of older people is set to increase dramatically worldwide. Demographic changes are likely to result in the rise of age-related chronic diseases which largely contribute to years lived with a disability and future dependence. However dependence is much less studied although intrinsically linked to disability. We investigated the prevalence and correlates of dependence among older people from middle income countries.</p> <p>Methods</p> <p>A one-phase cross-sectional survey was carried out at 11 sites in seven countries (urban sites in Cuba, Venezuela, and Dominican Republic, urban and rural sites in Peru, Mexico, China and India). All those aged 65 years and over living in geographically defined catchment areas were eligible. In all, 15,022 interviews were completed with an informant interview for each participant. The full 10/66 Dementia Research Group survey protocol was applied, including ascertainment of depression, dementia, physical impairments and self-reported diagnoses. Dependence was interviewer-rated based on a key informant's responses to a set of open-ended questions on the participant's needs for care. We estimated the prevalence of dependence and the independent contribution of underlying health conditions. Site-specific prevalence ratios were meta-analysed, and population attributable prevalence fractions (PAPF) calculated.</p> <p>Results</p> <p>The prevalence of dependence increased with age at all sites, with a tendency for the prevalence to be lower in men than in women. Age-standardised prevalence was lower in all sites than in the USA. Other than in rural China, dementia made the largest independent contribution to dependence, with a median PAPF of 34% (range 23%-59%). Other substantial contributors were limb impairment (9%, 1%-46%), stroke (8%, 2%-17%), and depression (8%, 1%-27%).</p> <p>Conclusion</p> <p>The demographic and health transitions will lead to large and rapid increases in the numbers of dependent older people particularly in middle income countries (MIC). The prevention and control of chronic neurological and neuropsychiatric diseases and the development of long-term care policies and plans should be urgent priorities.</p