Bowling Green State University

About: Bowling Green State University is a education organization based out in Bowling Green, Ohio, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 8315 authors who have published 16042 publications receiving 482564 citations. The organization is also known as: BGSU.

Ecophysiological Characterization of Ammonia-Oxidizing Archaea and Bacteria from Freshwater

Abstract: Aerobic biological ammonia oxidation is carried out by two groups of microorganisms, ammonia-oxidizing bacteria (AOB) and the recently discovered ammonia-oxidizing archaea (AOA). Here we present a study using cultivation-based methods to investigate the differences in growth of three AOA cultures and one AOB culture enriched from freshwater environments. The strain in the enriched AOA culture belong to thaumarchaeal group I.1a, with the strain in one enrichment culture having the highest identity with “Candidatus Nitrosoarchaeum koreensis” and the strains in the other two representing a new genus of AOA. The AOB strain in the enrichment culture was also obtained from freshwater and had the highest identity to AOB from the Nitrosomonas oligotropha group (Nitrosomonas cluster 6a). We investigated the influence of ammonium, oxygen, pH, and light on the growth of AOA and AOB. The growth rates of the AOB increased with increasing ammonium concentrations, while the growth rates of the AOA decreased slightly. Increasing oxygen concentrations led to an increase in the growth rate of the AOB, while the growth rates of AOA were almost oxygen insensitive. Light exposure (white and blue wavelengths) inhibited the growth of AOA completely, and the AOA did not recover when transferred to the dark. AOB were also inhibited by blue light; however, growth recovered immediately after transfer to the dark. Our results show that the tested AOB have a competitive advantage over the tested AOA under most conditions investigated. Further experiments will elucidate the niches of AOA and AOB in more detail.

Life stressors, neighborhood disadvantage, and resources: A focus on inner-city children's adjustment.

Abstract: Examined the contribution of particular stressors and resources to inner-city children's adjustment. Fourth, 5th, and 6th graders (N = 315; 66%from ethnic minority groups) reported on their recent exposure to stressful events and neighborhood disadvantage, their perceptiom of self-worth and social support, and their behavioral and academic adjustment. Hierarchical regressions indicated unique contributions of stressful events and neighborhood disadvantage to predicting antisocial behavior; higher levels of self-worth and family support were related to lower levels of antisocial behavior, but higher levels of peer support were related to higher levels of antisocial behavior. Furthermore, whereas family support buffered the relation between stressful events and antisocial behavior, peer support exacerbated the effect of stressors on behavioral maladjustment.

Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XI. Intensive Monitoring of the Ultraviolet Spectrum of NGC 7469

Abstract: From 1996 June 10 to July 29, the International Ultraviolet Explorer monitored the Seyfert 1 galaxy NGC 7469 continuously in an attempt to measure time delays between the continuum and emission-line fluxes. From the time delays, one can estimate the size of the region dominating the production of the UV emission lines in this source. We find the strong UV emission lines to respond to continuum variations with time delays of about 23-31 for Lyα, 27 for C IV λ1549, 19-24 for N V λ1240, 17-18 for Si IV λ1400, and 07-10 for He II λ1640. The most remarkable result, however, is the detection of apparent time delays between the different UV continuum bands. With respect to the UV continuum flux at 1315 A, the flux at 1485 A, 1740 A, and 1825 A lags with time delays of 021, 035, and 028, respectively. Determination of the significance of this detection is somewhat problematic since it depends on accurate estimation of the uncertainties in the lag measurements, which are difficult to assess. We attempt to estimate the uncertainties in the time delays through Monte Carlo simulations, and these yield estimates of ~007 for the 1 σ uncertainties in the interband continuum time delays. Possible explanations for the delays include the existence of a continuum-flux reprocessing region close to the central source and/or a contamination of the continuum flux with a very broad time-delayed emission feature such as the Balmer continuum or merged Fe II multiplets.

New Ru(II) Chromophores with Extended Excited-State Lifetimes

Abstract: We describe the synthesis, electrochemical, and photophysical properties of two new luminescent Ru(II) diimine complexes covalently attached to one and three 4-piperidinyl-1,8-naphthalimide (PNI) chromophores, [Ru(bpy)2(PNI−phen)](PF6)2 and [Ru(PNI−phen)3](PF6)2, respectively. These compounds represent a new class of visible light-harvesting Ru(II) chromophores that exhibit greatly enhanced room-temperature metal-to-ligand charge transfer (MLCT) emission lifetimes as a result of intervening intraligand triplet states (3IL) present on the pendant naphthalimide chromophore(s). In both Ru(II) complexes, the intense singlet fluorescence of the pendant PNI chromophore(s) is nearly quantitatively quenched and was found to sensitize the MLCT-based photoluminescence. Excitation into either the 1IL or 1MLCT absorption bands results in the formation of both 3MLCT and 3IL excited states, conveniently monitored by transient absorption and fluorescence spectroscopy. The relative energy ordering of these triplet states...