Functional Nanoparticles in Thin Films as Sensing Media

The combination of unique properties offered by materials on the nanoscale with the increased role of surface chemistry in nanostructured solids makes core-shell nanoparticles extremely attractive for application to smart thin-film coatings. Sensing properties of nanoparticle-based thin films were studied in several systems containing organic-coated semiconductor and metallic particles. In semiconductors, the interaction of organic shell and/or thin-film matrix with the environment results in changes in the nanoparticle\u27s surface states, altering the optical properties of the thin film. Measuring the electrical properties of thin films composed of metallic cores with hydrocarbon shells offers another mechanism to monitor the local environment through the swelling of the hydrocarbons in the presence of external compounds. These mechanisms and their potential application to novel sensors will be discussed

Surficial geologic materials of the Marion Quadrangle, Iowa

https://ir.uiowa.edu/igs_ofm/1002/thumbnail.jp

Measurement of [OIII] Emission in Lyman Break Galaxies

Measurements of [OIII] emission in Lyman Break galaxies (LBGs) at z>3 are presented. Four galaxies were observed with narrow-band filters using the Near-IR Camera on the Keck I 10-m telescope. A fifth galaxy was observed spectroscopically during the commissioning of NIRSPEC, the new infrared spectrometer on Keck II. The emission-line spectrum is used to place limits on the metallicity. Comparing these new measurements with others available from the literature, we find that strong oxygen emission in LBGs may suggest sub-solar metallicity for these objects. The [OIII]5007 line is also used to estimate the star formation rate (SFR) of the LBGs. The inferred SFRs are higher than those estimated from the UV continuum, and may be evidence for dust extinction.Comment: 25 pages, including 6 figures. Accepted for publication in Ap

Bedrock geology of Linn County

https://ir.uiowa.edu/igs_ofm/1004/thumbnail.jp

Depression: An Important Comorbidity With Metabolic Syndrome in a General Population

OBJECTIVE—There is a recognized association among depression, diabetes, and cardiovascular disease. The aim of this study was to examine in a sample representative of the general population whether depression, anxiety, and psychological distress are associated with metabolic syndrome and its components

Surficial geologic materials of the Cedar Rapids South Quadrangle

https://ir.uiowa.edu/igs_ofm/1005/thumbnail.jp

Physical Properties of Emission-Line Galaxies at z ~ 2 from Near-Infrared Spectroscopy with Magellan FIRE

We present results from near-infrared spectroscopy of 26 emission-line galaxies at z ~ 2 obtained with the FIRE spectrometer on the Magellan Baade telescope. The sample was selected from the WISP survey, which uses the near-infrared grism of the Hubble Space Telescope Wide Field Camera 3 to detect emission-line galaxies over 0.3 < z < 2.3. Our FIRE follow-up spectroscopy (R~5000) over 1.0-2.5 micron permits detailed measurements of physical properties of the z~2 emission-line galaxies. Dust-corrected star formation rates for the sample range from ~5-100 M_sun yr-1. We derive a median metallicity for the sample of ~0.45 Z_sun, and the estimated stellar masses range from ~10^8.5 - 10^9.5 M_sun. The average ionization parameters measured for the sample are typically much higher than what is found for local star-forming galaxies. We derive composite spectra from the FIRE sample, from which we infer typical nebular electron densities of ~100-400 cm^-3. Based on the location of the galaxies and composite spectra on BPT diagrams, we do not find evidence for significant AGN activity in the sample. Most of the galaxies as well as the composites are offset in the BPT diagram toward higher [O III]/H-beta at a given [N II]/H-alpha, in agreement with other observations of z > 1 star-forming galaxies, but composite spectra derived from the sample do not show an appreciable offset from the local star-forming sequence on the [O III]/H-beta versus [S II]/H-alpha diagram. We infer a high nitrogen-to-oxygen abundance ratio from the composite spectrum, which may contribute to the offset of the high-redshift galaxies from the local star-forming sequence in the [O III]/H-beta versus [N II]/H-alpha diagram. We speculate that the elevated nitrogen abundance could result from substantial numbers of Wolf-Rayet stars in starbursting galaxies at z~2. (Abridged)Comment: Accepted for publication in Ap

Evolution of star formation in the UKIDSS ultra deep survey field-I. Luminosity functions and cosmic star formation rate out to z = 1.6

We present new results on the cosmic star formation history in the Subaru/XMM-Newton Deep Survey (SXDS)-Ultra Deep Survey (UDS) field out to z = 1.6. We compile narrowband data from the Subaru Telescope and the Visible and Infrared Survey Telescope forAstronomy (VISTA) in conjunction with broad-band data from the SXDS and UDS, to makea selection of 5725 emission-line galaxies in 12 redshift slices, spanning 10 Gyr of cosmictime. We determine photometric redshifts for the sample using 11-band photometry, and usea spectroscopically confirmed subset to fine tune the resultant redshift distribution. We usethe maximum-likelihood technique to determine luminosity functions in each redshift slice and model the selection effects inherent in any narrow-band selection statistically, to obviatethe retrospective corrections ordinarily required. The deep narrow-band data are sensitive tovery low star formation rates (SFRs), and allow an accurate evaluation of the faint end slopeof the Schechter function, α We find that a is particularly sensitive to the assumed faintest broad-band magnitude of a galaxy capable of hosting an emission line, and propose thatthis limit should be empirically motivated. For this analysis, we base our threshold on thelimiting observed equivalent widths of emission lines in the local Universe. We compute thecharacteristic SFR of galaxies in each redshift slice, and the integrated SFR density,ρ SFR. Wefind our results to be in good agreement with the literature and parametrize the evolution of the SFR density as ρ SFR α(1 + z)4.58 confirming a steep decline in star formation activity since z ~ 1.6.Peer reviewe

Surficial geologic materials of the Central City Quadrangle

https://ir.uiowa.edu/igs_ofm/1006/thumbnail.jp