2,927 research outputs found

    Quinoline synthesis: scope and regiochemistry of photocyclisation of substituted benzylidenecyclopentanone O-alkyl and O-acetyloximes

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    Irradiation of substituted 2-benzylidenecyclopentanone O-alkyl and O-acetyloximes in methanol provides a convenient synthesis of alkyl, alkoxy, hydroxy, acetoxy, amino, dimethylamino and benzo substituted annulated quinolines. para-Substituents yield 6-substituted-2,3-dihydro-1H-cyclopenta[b]quinolines with 8-substituted products being obtained from ortho-substituted starting materials. Reactions of meta-substituted precursors are highly regioselective, with alkyl substituents leading to 5-substituted 2,3-dihydro-1H-cyclopenta[b]quinolines and more strongly electron-donating substituents generally resulting in 7-substituted products. 2-Furylmethylene and 2-thienylmethylene analogues yield annulated furo- and thieno-[2,3e]pyridines respectively. Sequential E- to Z-benzylidene group isomerisation and six [pi]-electron cyclisation steps result in formation of a short-lived dihydroquinoline intermediate which spontaneously aromatises by elimination of an alcohol or acetic acid. For 2-benzylidenecyclopentanone O-allyloxime, singlet excited states are involved in both steps

    Nova Sagittarii 1994 #1 (V4332 Sagittarii): The Discovery and Evolution of an Unusual Luminous Red Variable Star

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    We report photometry and spectroscopy of the evolution of Nova Sagittarii 1994 #1 (V4332 Sagittarii) during outburst. We compare the photometric and spectral evolution of this outburst to known classes of outbursts -- including classical novae and outbursts occurring on symbiotic stars -- and find this object does NOT conform to any known class of outburst. The closest match to the behavior of this unusual object is M31 RV, an extremely luminous and red variable object discovered in the bulge of M31 in 1988. However, the temporal behavior and maximum luminosity of the two events differ by several orders of magnitude, requiring substantial intrinsic variation if these two events are members the same type of outburst. Our model of the spectroscopic evolution of this outburst shows that the effective temperature cooled from 4400 K to 2300 K over the three month span of our observations. In combination with line diagnostics in our later spectra, including [OI] lambda 5577 and the dramatic increase in the Halpha to Hbeta ratio, we infer the existence of a cool, dense (N_e ~ 10^{8-9} cm^{-3}) envelope that is optically thick in the Hydrogen Balmer recombination lines (case C). We suggest that a nuclear event in a single star, in which a slow shock drove the photosphere outwards, can power the observed luminosity evolution and the emission spectrum.Comment: Accepted for publication in AJ. 24 pages including 8 embedded postscript figures. Also available at http://www.astronomy.ohio-state.edu/~martini/pub

    Associations between body mass index and suicide in the veterans affairs health system

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102714/1/oby20422.pd

    Predictors of injury-related and non-injury-related mortality among veterans with alcohol use disorders

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    To describe the association between alcohol use disorders (AUDs) and mortality and to examine risk factors for and all-cause, injury-related and non-injury-related mortality among those diagnosed with an AUD.Department of Veterans Affairs, Veterans Health Administration (VHA).A cohort of individuals who received health care in VHA during the fiscal year (FY) 2001 ( n  = 3 944 778), followed from the beginning of FY02 through the end of FY06.Demographics and medical diagnoses were obtained from VHA records. Data on mortality were obtained from the National Death Index.Controlling for age, gender and race and compared to those without AUDs, individuals with AUDs were more likely to die by all causes [hazard ratio (HR) = 2.30], by injury-related (HR = 3.29) and by non-injury-related causes (HR = 2.21). Patients with AUDs died 15 years earlier than individuals without AUDs on average. Among those with AUDs, Caucasian ethnicity and all mental illness diagnoses that were assessed were associated more strongly with injury-related than non-injury-related mortality. Also among those with AUDs, individuals with medical comorbidity and older age were at higher risk for non-injury related compared to injury-related mortality.In users of a large health-care system, a diagnosis of an AUD is associated significantly with increased likelihood of dying by injury and non-injury causes. Patients with a diagnosis of an AUD who die from injury differ significantly from those who die from other medical conditions. Prevention and intervention programs could focus separately upon selected groups with increased risk for injury or non-injury-related death.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79146/1/j.1360-0443.2010.03024.x.pd

    Detection of Lyman-Alpha Emission From a Triple Imaged z=6.85 Galaxy Behind MACS J2129.4-0741

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    We report the detection of Lyα\alpha emission at 9538\sim9538\AA{} in the Keck/DEIMOS and \HST WFC3 G102 grism data from a triply-imaged galaxy at z=6.846±0.001z=6.846\pm0.001 behind galaxy cluster MACS J2129.4-0741. Combining the emission line wavelength with broadband photometry, line ratio upper limits, and lens modeling, we rule out the scenario that this emission line is \oii at z=1.57z=1.57. After accounting for magnification, we calculate the weighted average of the intrinsic Lyα\alpha luminosity to be 1.3×1042 erg s1\sim1.3\times10^{42}~\mathrm{erg}~\mathrm{s}^{-1} and Lyα\alpha equivalent width to be 74±1574\pm15\AA{}. Its intrinsic UV absolute magnitude at 1600\AA{} is 18.6±0.2-18.6\pm0.2 mag and stellar mass (1.5±0.3)×107 M(1.5\pm0.3)\times10^{7}~M_{\odot}, making it one of the faintest (intrinsic LUV0.14 LUVL_{UV}\sim0.14~L_{UV}^*) galaxies with Lyα\alpha detection at z7z\sim7 to date. Its stellar mass is in the typical range for the galaxies thought to dominate the reionization photon budget at z7z\gtrsim7; the inferred Lyα\alpha escape fraction is high (10\gtrsim 10\%), which could be common for sub-LL^* z7z\gtrsim7 galaxies with Lyα\alpha emission. This galaxy offers a glimpse of the galaxy population that is thought to drive reionization, and it shows that gravitational lensing is an important avenue to probe the sub-LL^* galaxy population.Comment: Accepted by ApJ Letter

    The social lives of isolates (and small language families):The case of the Northwest Amazon

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    The Americas are home to patches of extraordinary linguistic (genealogical) diversity. These high-diversity areas are particularly unexpected given the recent population of the Americas. In this paper, we zoom in on one such area, the Northwest Amazon, and address the question of how the diversity in this area has persisted to the present. We contrast two hypotheses that claim opposite mechanisms for the maintenance of diversity: the isolation hypothesis suggests that isolation facilitates the preservation of diversity, while the integration hypothesis proposes that conscious identity preservation in combination with contact drives diversity maintenance. We test predictions for both hypotheses across four disciplines: biogeography, cultural anthropology, population genetics and linguistics. Our results show signs of both isolation and integration, but they mainly suggest considerable diversity in how groups of speakers have interacted with their surroundings

    Galileons as Wess-Zumino Terms

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    We show that the galileons can be thought of as Wess-Zumino terms for the spontaneous breaking of space-time symmetries. Wess-Zumino terms are terms which are not captured by the coset construction for phenomenological Lagrangians with broken symmetries. Rather they are, in d space-time dimensions, d-form potentials for (d+1)-forms which are non-trivial co-cycles in Lie algebra cohomology of the full symmetry group relative to the unbroken symmetry group. We introduce the galileon algebras and construct the non-trivial (d+1)-form co-cycles, showing that the presence of galileons and multi-galileons in all dimensions is counted by the dimensions of particular Lie algebra cohomology groups. We also discuss the DBI and conformal galileons from this point of view, showing that they are not Wess-Zumino terms, with one exception in each case.Comment: 49 pages. v2 minor changes, version appearing in JHE

    Discovery of a Mid-L Dwarf Companion to the L 262-74 System

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    We present the discovery of CWISE J151044.74-524923.5, a wide low-mass companion to the nearby (\sim24.7 pc) system L 262-74, which was identified through the Backyard Worlds: Planet 9 citizen science project. We detail the properties of the system, and we assess that this companion is a mid-L dwarf, which will need to be verified spectroscopically. With an angular separation of 74\farcs3, we estimate a projected physical separation of \sim1837 au from the central system
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