Digital Commons Network^™

Dissertation Distress: A Room Of One's Own With A Crib And A Computer, Joanne Detore-Nakamura

Publications

The author writes of her efforts to finish her doctoral dissertation while rearing a toddler. Adjustments must be made.

Using Optical And Near-Infrared Photometry To Test Macho Lens Candidates, Ted Von Hippel, Et Al.

Publications

We obtained new VLT/ISAAC H-band observations for five MACHO LMC source stars and adjacent LMC field regions. After combining our near-IR photometry with Hubble Space Telescope/PC BVRI optical photometry, we compared the MACHO objects to the adjacent field stars in a variety of color-magnitude and color-color diagrams. These diagnostic diagrams were chosen to be sensitive to our hypothesis that at least some of the MACHO lenses were foreground Galactic disk or thick-disk M dwarfs. For the five lensed objects we studied, our hypothesis could be ruled out for main-sequence lens masses ≥0.1 M☉ for distances out to …

Constraining The Evolution Of Zz Ceti, Anjum S. Mukadam, S. O. Kepler, D. E. Nather, M. Kilic, F. Mullally, T. Von Hippel, S. J. Kleinman, A. Nitta, J. A. Guzik, P. A. Bradley, J. Matthews, K. Sekiguchi, D. J. Sullivan, T. Sullivan, R. R. Shobbrook, P. Birch, X. J. Jiang, D. W. Xu, S. Joshi, B. N. Ashoka, P. Ibbetson, E. Leibowitz, E. O. Ofek, E. G. Meištas, R. Janulis, R. D. Ališauskas, R. Kalytis, G. Handler, D. Kilkenny, D. O'Donoghue, D. W. Kurtz, M. Müller, P. Moskalik, W. Ogloza, S. Zola, J. Krzesiński, F. Johnannessen, J. M. Gonzalez-Perez, J. E. Solheim, R. Silvotti, S. Bernabei, G. Vauclair, N. Dolez, J. N. Fu, M. Chevreton, M. Manteiga, O. Suárez, A. Ulla, M. S. Cunha, T. S. Metcalfe, A. Kanaan, L. Fraga, A. F. M. Costa, O. Giovannini, G. Fontaine, P. Bergeron, M. S. O'Brien, D. Sanwal, M. A. Wood, T. J. Ahrens, N. Silvestri, E. W. Klumpe, S. D. Kawaler, R. Riddle, M. D. Reed, T. K. Watson

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We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf) ZZ Ceti, also called R548. On the basis of observations that span 31 years, we conclude that the period 213.13 s observed in ZZ Ceti drifts at a rate dP/dt ≤ (5:5 ± 1:9) x 10^-15 s s^-1, after correcting for proper motion. Our results are consistent with previous Ṗ values for this mode and an improvement over them because of the larger time base. The characteristic stability timescale implied for the pulsation period is …

Grb 011121: A Collimated Outflow Into Wind-Blown Surroundings, Dieter H. Hartmann, J. Greiner, S. Klose, M. Salvato, A. Zeh, R. Schwarz, N. Masetti, B. Stecklum, G. Lamer, N. Lodieu

Publications

We report optical and near-infrared follow-up observations of GRB 011121 collected predominantly at ESO telescopes in Chile. We discover a break in the afterglow light curve after 1.3 days, which implies an initial jet opening angle of about 9°. The jet origin of this break is supported by the fact that the spectral energy distribution is achromatic during the rst four days. During later phases, GRB 011121 shows signi cant excess emission above the flux predicted by a power law, which we interpret as additional light from an underlying supernova. In particular, the spectral energy distribution of the optical transient …

Supernova Reverse Shocks: Sic Growth And Isotopic Composition, Ethan A-N. Deneault, Donald D. Clayton, Alexander Heger

Publications

We present new mechanisms by which the isotopic compositions of X-type grains of presolar SiC are altered by reverse shocks in Type II supernovae. We address three epochs of reverse shocks: pressure wave from the H envelope near t ¼ 106 s, reverse shock from the presupernova wind near 108–109 s, and reverse shock from the interstellar medium near 1010 s. Using one-dimensional hydrodynamics we show that the first creates a dense shell of Si and C atoms near 106 s in which the SiC surely condenses. The second reverse shock causes precondensed grains to move rapidly forward through decelerated …

Spatial And Temporal Variability Of The Gamma Radiation From Earth's Atmosphere During A Solar Cycle, Michael J. Harris, Gerald H. Share, Mark D. Leising

Publications

The Solar Maximum Mission satellite’s Gamma Ray Spectrometer spent much of its 1980–1989 mission pointed at Earth, accumulating spectra of atmospheric albedo γ-rays. Its 28◦ orbit ensured that a range of geomagnetic latitudes was sampled. We measured the variation with time and cutoff rigidity of some key γ-ray lines which are diagnos-tic of the intensity of the Galactic cosmic radiation penetrating the geomagnetic cutoff and of the secondary neutrons produced in the atmosphere. We found that the inten-sities of nuclear lines at 1.6 MeV, 2.3 MeV and 4.4 MeV varied inversely with solar ac-tivity in cycles 21–22 as expected from …

The Very Faint K-Band Afterglow Of Grb 020819 And The Dust Extinction Hypothesis Of The Dark Bursts, Dieter H. Hartmann, S. Klose, A. A. Henden, J. Greiner, N. Cardiel, A. J. Castro-Tirado, J. M. Castro Cerón, J. Gallego, J. Gorsosabel, B. Stecklum

Publications

We report rapid follow-up K'-band observations of the error box of the bright High Energy Transient Explorer burst GRB 020819. We find that any afterglow was fainter than K' ¼ 19 only 9 hr after the burst. Because no optical afterglow was found, GRB 020819 represents a typical ‘‘dark burst.’’ At first, we discuss if extinction by cosmic dust in the GRB host galaxy could explain the faintness of the afterglow of GRB 020819. We then turn to the entire ensemble of K-band dark afterglows. We find that extinction by cosmic dust in the GRB host galaxies is still a …

Understanding Latitudinal Trends In Fish Body Size Through Models Of Optimal Seasonal Energy Allocation, James E. Garvey, Elizabeth A. Marschall

Publications

For fish at high latitudes, short growing seasons should constrain size-at-age, although the converse often occurs. We used a dynamic state variable model to find energy allocation strategies to length, fat, and ovaries that maximize expected egg production of largemouth bass (Micropterus salmoides). We determined how latitudes and rations affect optimal allocation and then simulated growth using optimal strategies. A theoretical reciprocal transplant explored how latitude-specific optimal strategies affected growth at other latitudes. At low ration, allocation and growth were similar among latitudes, with length selected in small individuals and reproductive tissue and fat in large counterparts. At …

"Have You Written A Ford, Lately?": Gender, Genre, And The Film Adaptations Of Dorothy Johnson's Western Literature, Walter C. Metz

Publications

This essay studies the role Dorothy Johnson, a mid-century female author of American Western stories, had on the development of the film Western, particularly given that she wrote the story on which John Ford's canonical The Man Who Shot Liberty Valence (1962) was based.

Multisite Observations Of The Pms Δ Delta Scuti Star V351 Ori, V. Ripepi, Terry D. Oswalt, M. Marconi, S. Bernabei, Et Al.

Publications

We present the results of multisite observations spanning two years on the pre–main-sequence (PMS) star V351 Ori. A total of around 180 hours of observations over 29 nights have been collected, allowing us to measure five different periodicities, most likely related to the Scuti variability of V351 Ori. Comparison with the predictions of linear nonadiabatic radial pulsation models put stringent constraints on the stellar parameters and indicate that the distance to V351 Ori is intermediate between the lower limit measured by Hipparcos (210 pc) and that of the Orion Nebula (450 pc). However, radial pulsation models are unable to reproduce …

Life-History Variation In The Sagebrush Lizard (Sceloporus Graciosus): Phenotypic Plasticity Or Local Adaptation?, Michael W. Sears

Publications

We performed a laboratory common-environment study to determine the genetic and environmental sources of variation in growth rates of the sagebrush lizard (Sceloporus graciosus). Hatchling lizards were reared from gravid females collected from three study populations along an elevational gradient in southern Utah, USA. Hatchlings were fed ad libidum and were maintained on a 14:10 light:dark cycle, with temperatures at 33°C and 21°C during photophase and scotophase, respectively. Each hatchling was randomly assigned to either a water-supplementation treatment or a control group receiving no supplemental water. Once every five days, the water-supplemented lizards were administered orally a quantity …

Constraining The Cosmic Star Formation Rate With The Mev Background, K Watanabe, D H. Hartmann, Mark D. Leising, L. S. The

Publications

The Cosmic Gamma-ray Background (CGB) in the MeV regime has been measured with COMPTEL and SMM. The origin of the CGB in this energy regime is believed to be dominated by gamma-rays from Type Ia supernovae. We calculate the CGB spectrum within the framework of FRW cosmology as a function of the cosmic star formation rate, SFR(z). Several estimates of the SFR(z) have been reported since the pioneering work of Madau et al. Here we discuss observational constraints on SFR(z) derived from models of the CGB. In particular, we consider the SFR obtained from Gamma-Ray Burst observations, which increases dramatically …

Co Emission From Disks Around Ab Aurigae And Hd 141569: Implications For Disk Structure And Planet Formation Timescales, Sean D. Brittain, Terrence W. Rettig, Theodore Simon, Craig Kulesa, Michael A. Disanti, Neil Dello Russo

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We present a comparison of CO fundamental rovibrational lines (observed in the M band near 4.7 μm) from the inner circumstellar disks around the Herbig AeBe stars AB Aur and HD 141569. The CO spatial profiles and temperatures constrain the location of the gas for both stars to a distance of less than 50 AU. The CO emission from the disk of the ~4 Myr star AB Aur shows at least two temperature components, the inner disk at a rotational temperature of 1540 ± 80 K and the outer disk at 70 ± 10 K. The hot gas is located …

Magnetic Behavior Of Iron-Oxoclusters Prepared In An Organosilica Sol–Gel Matrix, I. S. Dubenko, M. S. Rao, S. Roy, B. C. Dave, N. Ali

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The crystal structure and magnetization of nanoscale enTMOS–Fe₂O₃ sol–gel composites with weight iron concentration x, varying from 0.003 to 0.065, have been studied by the transmission electron microscopy technique and a superconducting quantum interference device magnetometer. The clusters are crystallized in a hexagonal crystal structure. All the samples demonstrate a superparamagnetic behavior with antiferomagnetic cluster–cluster coupling at low temperature. The effective paramagnetic moment, μ_eff, has been found to vary in the range from 5.9 (S=5/2) to 2.5 μ_B per iron ion. The concentration dependence of the μ_eff shows a minimum …

Unusual Electronic Transport Properties In La0.96−Xndxk0.04mno3, Yongquan Guo, Sujoy Roy, Naushad Ali, Xinhui Zhang, Roger Wäppling

Publications

Polycrystalline La_0.96−xNd_xK_0.04MnO₃ has been studied by means of x-ray powder diffraction, dc magnetization, and electrical resistance measurement. La_0.96−xNd_xK_0.04MnO₃ initially crystallizes in a rhombohedral distorted perovskite structure. However, an orthorhombic structure is obtained with increasing Nd content more than 20%. Both the rhombohedral and the orthorhombic phases show ferromagnetic order. However, the compound shows a magnetic inhomogeneity behavior with increasing Nd content. With increasing Nd doping, the ferromagnetic order is significantly weakened, and the second magnetic transition occurs at a low temperature and its peak …

Magnetic Phase Transitions In (Tb,Y)Mn2m2 (M=Ge And Si) Systems, I. S. Dubenko, I. Yu. Gaidukova, S. A. Granovsky, K. Inoue, A. S. Markosyan, S. Roy, N. Ali

Publications

The temperature- and field-induced magnetic phase transitions in pseudoternary systems Tb_1−xY_xMn₂Ge₂ and Tb_1−xY_xMn₂Si₂, which are characterized by a separate magnetic ordering of the Mn and Tb subsystems, have been studied on strongly textured samples by magnetization and thermal expansion measurements. In the concentration region 0.4≤ x≤ 1.0, where the Mn moments are ordered only, the magnetic structure is antiferromagnetic. The magnetic ordering in the Tb subsystem is accompanied by a transformation of the Mn magnetic structure. As a result, the compounds show …

Uaa Student Showcase Journal: Recognizing Excellence (2003), N/A N/A

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No abstract provided.

An Algorithm For Generating Exact Critical Values For The Kruskal-Wallis One-Way Anova, Todd C. Headrick

Publications

A Fortran 77 subroutine is provided for computing exact critical values for the Kruskal- Wallis test on k independent groups with equal or unequal samples sizes. The subroutine requires the user to provide sorting and ranking routines and a uniform pseudo-random number generator. The program is available from the author on request.

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Spectroscopic Abundances Of Solar-Type Dwarfs In The Open Cluster M34 (Ngc 1039), Simon C. Schuler, Jeremy R. King, Debra A. Fischer, David R. Soderblom, Burton F. Jones

Publications

Parameters and relative abundances of Fe, Ni, Ti, Cr, Ca, Si, Al, and Mg have been derived for nine M34 G and K dwarfs from high-resolution, modest signal-to-noise ratio Keck HIRES spectra. Effective temperatures have been derived spectroscopically and fall in the range 4750 K Teff 6130 K. Despite modest scatter in Fe, Ti, Cr, Ca, Al, and Mg (none of which is found to be correlated with Li scatter in M34), our two coolest stars are slightly though consistently underabundant in these elements relative to the warmer stars. The two cool stars are slightly overabundant in Si, whose abundances …

Stellar Kinematic Groups. Ii. Reexamination Of The Membership, Activity, And Age Of The Ursa Major Group, Jeremy R. King, Adam R. Villarreal, David R. Soderblom, Austin F. Gulliver, Saul J. Adelman

Publications

Utilizing Hipparcos parallaxes, original radial velocities and recent literature values, new Ca ii H and K emission measurements, literature-based abundance estimates, and updated photometry (including recent resolved measurements of close doubles), we revisit the Ursa Major moving group membership status of some 220 stars to produce a final clean list of nearly 60 assured members, based on kinematic and photomet-ric criteria. Scatter in the velocity dispersions and H-R diagram is correlated with trial activity-based mem-bership assignments, indicating the usefulness of criteria based on photometric and chromospheric emission to examine membership. Closer inspection, however, shows that activity is considerably more robust …

El Nacionalismo Democrático Español En Carlos Saura: Carmen (1983) Y Goya En Burdeos (1999), Salvador Oropesa

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No abstract provided.

The Nematode Fauna Of Long-Nosed Mice Oxymycterus Spp. From The Bolivian Yungas, F Agustín Jiménez-Ruiz, Scott Lyell Gardner

Publications

During a long-term survey of the parasites of mammals from all over Bolivia, 44 individuals of Oxymycterus inca and 6 of Oxymycterus paramensis were collected and examined for parasites from the foothills and Eastern Cordillera (Los Yungas) of the Andes of Bolivia. Three species of nematode were found including, from the cecum, a previously unknown genus and species of pinworm, Caroloxyuris boliviensis n. gen, n. sp., aspidoderids representing Nematomystes rodentophilus, and from the stomach, Protospirura numidica criceticola. These helminths occurred in prevalences of 25, 9, and 14%, respectively, in O. paramensis. Caroloxyuris boliviensis resembles species included in …

Fire Behavior Of Some Southern California Live Chaparral Fuels, Lulu Sun, Xiangyang Zhou, Shankar Mahalingam, David R. Weise

Publications

Wildfire spread in living vegetation, such as chaparral in southern California, often causes significant damage to infrastructure and ecosystems. In order to study wildfire spread in living vegetation, four of the most common chaparral in southern California, chamise, manzanita, scrub oak and ceanothus, were burned and compared. The observed fire behavior included mass loss rate, flame height, temperature structure and velocity field above the burning fuel bed. It was observed that flame height increases mainly with heat release rate. By using successive images of the temperature field, a recently developed thermal particle image velocity (TPIV) algorithm was applied to estimate …

Beryllium Abundances In F And G Dwarfs In The Coma Cluster And The Ursa Major Group From Keck Hires Observation, Ann Merchant Boesgaard, Eric Armengaud, Jeremy R. King

Publications

The study of both light elements Li and Be in open clusters of known properties can reveal the internal structure and the mechanisms of mixing in main-sequence stars as a function of age and composition. In previous work, we have investigated the older Hyades cluster and the younger Pleiades and Per clusters. The Coma Berenices cluster and the UMa moving group are intermediate in age between the Hyades and Pleiades and provide a good linchpin for the influence of stellar age on light-element abundances; there are dips in the mid-F stars in both Li and Be in the Hyades but …

Energetic Adaptations Along A Broad Latitudinal Gradient: Implications For Widely Distributed Assemblages, James E. Garvey, Dennis R. Devries, Russell A. Wright, Jeffrey G. Miner

Publications

Most community-based models in ecology assume that all individuals within a species respond similarly to environmental conditions and thereby exert identical effects as consumers or prey. Rather, individuals differ among systems, with important implications for population demographics and community interactions. For widely distributed assemblages made up of poikilotherms with high first-year mortality, species-specific differences in growth reaction norms as affected by both temperature and genotype will influence biotic interactions. For a broadly distributed fish assemblage, first-year growth does not vary with latitude for a planktivorous prey species, but declines with increasing latitude for a terminal piscivore. Size-based competitive interactions between …

Use Of Bridges As Day Roosts By Bats In Southern Illinois, George A. Feldhamer, Timothy C. Carter, Anita T. Morzillo, Erica H. Nicholson

Publications

From May through July 2001, and June through August 2002 we surveyed 232 bridges in 9 southern Illinois counties for the presence of roosting bats. Fifteen bridges (6.5%) had bats roosting at the time they were surveyed. We encountered big brown bats (Eptesicus fuscus) most frequently. Eastern pipestrelles (Pipestrellus subflavus), little brown bats (Myotis lucifugus), and northern long-eared bats (M. septentrionalis) also were found roosting under bridges. The number of bats per bridge ranged from 1 to >100. Bats occurred in four of the five types of bridge designs surveyed. Of the …

Efficient Targeting Of Protein Antigen To The Dendritic Cell Receptor Dec-205 In The Steady State Leads To Antigen Presentation On Major Histocompatibility Complex Class I Products And Peripheral Cd8+ T Cell Tolerance, Laura C. Bonifaz, David P. Bonnyay, Karsten Mahnke

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To identify endocytic receptors that allow dendritic cells (DCs) to capture and present antigens on major histocompatibility complex (MHC) class I products in vivo, we evaluated DEC-205, which is abundant on DCs in lymphoid tissues. Ovalbumin (OVA) protein, when chemically coupled to monoclonal αDEC-205 antibody, was presented by CD11c⁺ lymph node DCs, but not by CD11c^- cells, to OVA-specific, CD4⁺ and CD8⁺ T cells. Receptor-mediated presentation was at least 400 times more efficient than unconjugated OVA and, for MHC class I, the DCs had to express transporter of antigenic peptides (TAP) transporters. When αDEC-205:OVA was injected …

Macrophages Control The Retention And Trafficking Of B Lymphocytes In The Splenic Marginal Zone, Mikael Karlsson, Rodolphe Renè Guinamard, Silvia M. Bolland

Publications

The marginal zone of the spleen is a precisely ordered region that contains specialized subsets of B lymphocytes and macrophages. Disruption of the negative signaling inositol phosphatase, SH2-containing inositol-5-phosphatase 1 (SHIP), results in the loss of marginal zone B cells (MZBs) with reorganization of marginal zone macrophages (MZMOs) to the red pulp of the spleen. This primary macrophage defect, as revealed by selectively depleting SHIP in myeloid cells shows that MZMOs are specifically required for the retention of MZBs. The MZMO phenotype was reverted in SHIP/Bruton's tyrosine kinase (Btk) double knockout mice, thus identifying the Btk activating pathway as an …

Influenza Virus-Induced Dendritic Cell Maturation Is Associated With The Induction Of Strong T Cell Immunity To A Coadministered, Normally Nonimmunogenic Protein, Marie K. Brimnes, Laura C. Bonifaz, Ralph M. Steinman, Thomas M. Moran

Publications

We evaluated the proposal that during microbial infection, dendritic cells (DCs) undergo maturation and present a mixture of peptides derived from the microbe as well as harmless environmental antigens. Mice were exposed to an aerosol of endotoxin free ovalbumin (OVA) in the absence or presence of influenza virus. In its absence, OVA failed to induce B and T cell responses and even tolerized, but with influenza, OVA-specific antibodies and CD8⁺ cytolytic T lymphocytes developed. With or without infection, OVA was presented selectively in the draining mediastinal lymph nodes, as assessed by the comparable proliferation of infused, CD8⁺ and …

Activation Of Natural Killer T Cells By Α-Galactosylceramide Rapidly Induces The Full Maturation Of Dendritic Cells In Vivo And Thereby Acts As An Adjuvant For Combined Cd4 And Cd8 T Cell Immunity To A Coadministered Protein, Shinichiro Fujii, Kanako Shimizu, Carol L. Smith

Publications

The maturation of dendritic cells (DCs) allows these antigen-presenting cells to initiate immunity. We pursued this concept in situ by studying the adjuvant action α-galactosylceramide (αGalCer) in mice. A single i.v. injection of glycolipid induced the full maturation of splenic DCs, beginning within 4 h. Maturation was manifest by marked increases in costimulator and major histocompatibility complex class II expression, interferon (IFN)-γ production, and stimulation of the mixed leukocyte reaction. These changes were not induced directly by αGalCer but required natural killer T (NKT) cells acting independently of the MyD88 adaptor protein. To establish that DC maturation was responsible for …