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Effect Of Seeing Tobacco Use In Films On Trying Smoking Among Adolescents: Cross Sectional Study, James D. Sargent, Michael L. Beach, Madeline A. Dalton, Leila A. Mott, Jennifer J. Tickle, M. Bridget Ahrens, Todd F. Heatherton Dec 2001

Effect Of Seeing Tobacco Use In Films On Trying Smoking Among Adolescents: Cross Sectional Study, James D. Sargent, Michael L. Beach, Madeline A. Dalton, Leila A. Mott, Jennifer J. Tickle, M. Bridget Ahrens, Todd F. Heatherton

Dartmouth Scholarship

Objective: To test the hypothesis that greater exposure to smoking in films is associated with trying smoking among adolescents.


A Pdz-Binding Motif Is Essential But Not Sufficient To Localize The C Terminus Of Cftr To The Apical Membrane, Michal I. Milewski, John E. Mickle, John K. Forrest, Diane M. Stafford, Bryan D. Moyer, Jie Cheng, William B. Guggino, Bruce A. Stanton, Garry R. Cutting Dec 2001

A Pdz-Binding Motif Is Essential But Not Sufficient To Localize The C Terminus Of Cftr To The Apical Membrane, Michal I. Milewski, John E. Mickle, John K. Forrest, Diane M. Stafford, Bryan D. Moyer, Jie Cheng, William B. Guggino, Bruce A. Stanton, Garry R. Cutting

Dartmouth Scholarship

Localization of ion channels and transporters to the correct membrane of polarized epithelia is important for vectorial ion movement. Prior studies have shown that the cytoplasmic carboxyl terminus of the cystic fibrosis transmembrane conductance regulator (CFTR) is involved in the apical localization of this protein. Here we show that the C-terminal tail alone, or when fused to the green fluorescent protein (GFP), can localize to the apical plasma membrane, despite the absence of transmembrane domains. Co-expression of the C terminus with full-length CFTR results in redistribution of CFTR from apical to basolateral membranes, indicating that both proteins interact with the …


Analysis Of Mitotic Microtubule-Associated Proteins Using Mass Spectrometry Identifies Astrin, A Spindle-Associated Protein, Gary J. Mack, Duane A. Compton Dec 2001

Analysis Of Mitotic Microtubule-Associated Proteins Using Mass Spectrometry Identifies Astrin, A Spindle-Associated Protein, Gary J. Mack, Duane A. Compton

Dartmouth Scholarship

We purified microtubules from a mammalian mitotic extract and obtained an amino acid sequence from each microtubule-associated protein by using mass spectrometry. Most of these proteins are known spindle-associated components with essential functional roles in spindle organization. We generated antibodies against a protein identified in this collection and refer to it as astrin because of its association with astral microtubule arrays assembled in vitro. Astrin is approximately 134 kDa, and except for a large predicted coiled-coil domain in its C-terminal region it lacks any known functional motifs. Astrin associates with spindle microtubules as early as prophase where it concentrates at …


Ccd Photometry Of The Classic Second-Parameter Globular Clusters M3 And M13, Soo-Chang Rey, Suk-Jin Yoon, Young-Wook Lee, Brian Chaboyer, Ata Sarajedini Dec 2001

Ccd Photometry Of The Classic Second-Parameter Globular Clusters M3 And M13, Soo-Chang Rey, Suk-Jin Yoon, Young-Wook Lee, Brian Chaboyer, Ata Sarajedini

Dartmouth Scholarship

We present high-precision V, B-V color-magnitude diagrams (CMDs) for the classic second-parameter globular clusters M3 and M13 from wide-field, deep CCD photometry. The data for the two clusters were obtained during the same photometric nights with the same instrument, allowing us to determine accurate relative ages. Based on a differential comparison of the CMDs using the Δ(B-V) method, an age difference of 1.7 ± 0.7 Gyr is obtained between these two clusters. We compare this result with our updated horizontal-branch (HB) population models, which confirm that the observed age difference can produce the …


Mobile-Agent Versus Client/Server Performance: Scalability In An Information-Retrieval Task, Robert S. Gray, David Kotz, Ronald A. Peterson, Joyce Barton, Daria Chacon, Peter Gerken, Martin Hofmann, Jeffrey Bradshaw, Maggie Breedy, Renia Jeffers, Niranjan Suri Dec 2001

Mobile-Agent Versus Client/Server Performance: Scalability In An Information-Retrieval Task, Robert S. Gray, David Kotz, Ronald A. Peterson, Joyce Barton, Daria Chacon, Peter Gerken, Martin Hofmann, Jeffrey Bradshaw, Maggie Breedy, Renia Jeffers, Niranjan Suri

Dartmouth Scholarship

Building applications with mobile agents often reduces the bandwidth required for the application, and improves performance. The cost is increased server workload. There are, however, few studies of the scalability of mobile-agent systems. We present scalability experiments that compare four mobile-agent platforms with a traditional client/server approach. The four mobile-agent platforms have similar behavior, but their absolute performance varies with underlying implementation choices. Our experiments demonstrate the complex interaction between environmental, application, and system parameters.


Interactions Among Environmental Drivers: Community Responses To Changing Nutrients And Dissolved Organic Carbon, Jennifer L. Klug, Kathryn L. Cottingham Dec 2001

Interactions Among Environmental Drivers: Community Responses To Changing Nutrients And Dissolved Organic Carbon, Jennifer L. Klug, Kathryn L. Cottingham

Dartmouth Scholarship

Biological communities are frequently exposed to environmental changes that cause measurable responses in properties of the community (hereafter called environmental drivers). Predicting how communities respond to changing environmental drivers is a fundamental goal of ecology. Making predictions, however, can be very difficult, particularly when multiple environmental drivers change simultaneously and there are interactions among the drivers. We investigated the effects of the interaction between changes in nutrient loading and changes in colored dissolved organic matter (measured as dissolved organic carbon, DOC) on the dynamics of phytoplankton communities over a 7‐yr period. In 1991, Long Lake, a small seepage lake in …


Memory And The Experience Of Hearing Music, W Jay Dowling, Barbara Tillman, Dan Ayers Dec 2001

Memory And The Experience Of Hearing Music, W Jay Dowling, Barbara Tillman, Dan Ayers

Dartmouth Scholarship

We report five experiments in which listeners heard the beginnings of classical minuets (or similar dances). The phrase in either measures 1-2 or measures 3-4 was selected as a target, tested at the end of the excerpt. A "beep" indicated the test item, which was a continuation of the minuet as written. Test items were targets (repetitions of the selected phrase), similar lures (imitations of targets), or different lures, and occurred after delays of 4-5, 15, or 30 s. We estimated the proportion of correct discriminations of targets from similar lures and targets from different lures. In Experiment 1, …


Anti-Class Ii Monoclonal Antibody-Targeted Vibrio Cholerae Tcpa Pilin: Modulation Of Serologic Response, Epitope Specificity, And Isotype, Jia-Yan Wu, Ronald K. Taylor, William F. Wade Dec 2001

Anti-Class Ii Monoclonal Antibody-Targeted Vibrio Cholerae Tcpa Pilin: Modulation Of Serologic Response, Epitope Specificity, And Isotype, Jia-Yan Wu, Ronald K. Taylor, William F. Wade

Dartmouth Scholarship

Toxin-coregulated pilus (TCP) is a colonization factor required for cholera infection. It is not a strong immunogen when delivered in the context of whole cells, yet pilus subunits or TcpA derivative synthetic peptides induce protective responses. We examined the efficacy of immunizing mice with TCP conjugated to anti-class II monoclonal antibodies (MAb) with or without the addition of cholera toxin (CT) or anti-CD40 MAb to determine if the serologic response to TcpA could be manipulated. Anti-class II MAb-targeted TCP influenced the anti-TCP peptide serologic response with respect to titer and isotype. Responses to TcpA peptide 4 were induced with class …


Evaluation Of A Tetracycline-Inducible Promoter In Staphylococcus Aureus In Vitro And In Vivo And Its Application In Demonstrating The Role Of Sigb In Microcolony Formation, B. T. Bateman, N. P. Donegan, T. M. Jarry, M. Palma Dec 2001

Evaluation Of A Tetracycline-Inducible Promoter In Staphylococcus Aureus In Vitro And In Vivo And Its Application In Demonstrating The Role Of Sigb In Microcolony Formation, B. T. Bateman, N. P. Donegan, T. M. Jarry, M. Palma

Dartmouth Scholarship

An inducible promoter system provides a powerful tool for studying the genetic basis for virulence. A variety of inducible systems have been used in other organisms, including pXyl-xylR-inducible promoter, the pSpac-lacI system, and the arabinose-inducible PBAD promoter, but each of these systems has limitations in its application to Staphylococcus aureus. In this study, we demonstrated the efficacy of a tetracycline-inducible promoter system in inducing gene expression in S. aureus in vitro and inside epithelial cells as well as in an animal model of infection. Using the xyl/tetO promoter::gfpuvr fusion carried on a shuttle …


Evaluation Of Cholera Vaccines Formulated With Toxin-Coregulated Pilin Peptide Plus Polymer Adjuvant In Mice, Jia-Yan Wu, William F. Wade, Ronald K. Taylor Dec 2001

Evaluation Of Cholera Vaccines Formulated With Toxin-Coregulated Pilin Peptide Plus Polymer Adjuvant In Mice, Jia-Yan Wu, William F. Wade, Ronald K. Taylor

Dartmouth Scholarship

Cholera is an acute diarrheal disease that is caused by the gram-negative bacterium Vibrio cholerae. The low efficacy of currently available killed-whole-cell vaccines and the reactinogenicity coupled with potential reversion of live vaccines have thus far precluded widespread vaccination for the control of cholera. Recent studies on the molecular nature of the virulence components that contribute to V. cholerae pathogenesis have provided insights into possible approaches for the development of a defined subunit cholera vaccine. Genetic analysis has demonstrated that the toxin-coregulated pilus (TCP) is the major factor that contributes to colonization of the human intestine by V. cholerae. In …


Immune Response Genes Modulate Serologic Responses To Vibrio Cholerae Tcpa Pilin Peptides, Michael D. Meeks, Terri K. Wade, Ronald K. Taylor, William F. Wade Dec 2001

Immune Response Genes Modulate Serologic Responses To Vibrio Cholerae Tcpa Pilin Peptides, Michael D. Meeks, Terri K. Wade, Ronald K. Taylor, William F. Wade

Dartmouth Scholarship

Cholera is an enteric disease caused by Vibrio cholerae. Toxin-coregulated pilus (TCP), a type 4 pilus expressed by V. cholerae, is a cholera virulence factor that is required for host colonization. The TCP polymer is composed of subunits of TcpA pilin. Antibodies directed against TcpA are protective in animal models of cholera. While natural or recombinant forms of TcpA are difficult to purify to homogeneity, it is anticipated that synthesized TcpA peptides might serve as immunogens in a subunit vaccine. We wanted to assess the potential for effects of the immune response (Ir) gene that could complicate a peptide-based …


Fine-Tuning Solution For Hybrid Inflation In Dissipative Chaotic Dynamics, Rudnei O. Ramos Nov 2001

Fine-Tuning Solution For Hybrid Inflation In Dissipative Chaotic Dynamics, Rudnei O. Ramos

Dartmouth Scholarship

We study the presence of chaotic behavior in phase space in the preinflationary stage of hybrid inflation models. This is closely related to the problem of initial conditions associated with these inflationary types of model. We then show how an expected dissipative dynamics of fields just before the onset of inflation can solve or ease considerably the problem of initial conditions, driving the system naturally toward inflation. The chaotic behavior of the corresponding dynamical system is studied by computation of the fractal dimension of the boundary in phase space separating inflationary from noninflationary trajectories. The fractal dimension for this boundary …


Hubble Space Telescope Wfpc2 Imaging Of Cassiopeia A, R. A. Fesen, J. A. Morse, R. A. Chevalier, K. J. Borkowski, C. L. Gerardy Nov 2001

Hubble Space Telescope Wfpc2 Imaging Of Cassiopeia A, R. A. Fesen, J. A. Morse, R. A. Chevalier, K. J. Borkowski, C. L. Gerardy

Dartmouth Scholarship

The young galactic supernova remnant Cassiopeia A was imaged with Wide Field Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope through filters selected to capture the complete velocity range of the remnant's main shell in several emission lines. The primary lines detected, along with the specific WFPC2 filters used, were [O III] λλ4959, 5007 (F450W), [N II] λ6583 (F658N), [S II] λλ6716, 6731 + [O II] λλ7319, 7330 + [O I] λλ6300, 6364 (F675W), and [S III] λλ9069, 9532 (F850LP). About three-quarters of the remnant's 4' diameter main shell was imaged with all four filters in three WFPC2 pointings, …


Il-1 Induces Collagenase-3 (Mmp-13) Promoter Activity In Stably Transfected Chondrocytic Cells: Requirement For Runx-2 And Activation By P38 Mapk And Jnk Pathways, John A. Mengshol, Matthew P. Vincenti, Constance E. Brinckerhoff Nov 2001

Il-1 Induces Collagenase-3 (Mmp-13) Promoter Activity In Stably Transfected Chondrocytic Cells: Requirement For Runx-2 And Activation By P38 Mapk And Jnk Pathways, John A. Mengshol, Matthew P. Vincenti, Constance E. Brinckerhoff

Dartmouth Scholarship

Osteoarthritic chondrocytes secrete matrix metalloproteinase-13 (MMP-13) in response to interleukin-1 (IL-1), causing digestion of type II collagen in cartilage. Using chondrocytic cells, we previously determined that IL-1 induced a strong MMP-13 transcriptional response that requires p38 MAPK, JNK and the transcription factor NF-κB. Now, we have studied the tissue-specific transcriptional regulation of MMP-13. Constitutive expression of the transcription factor Runx-2 correlated with the ability of a cell type to express MMP-13 and was required for IL-1 induction; moreover, Runx-2 enhanced IL-1 induction of MMP-13 transcription by synergizing with the p38 MAPK signaling pathway. Transiently transfected MMP-13 promoters were not IL-1 …


The Type 2 Iodothyronine Deiodinase Is Essential For Adaptive Thermogenesis In Brown Adipose Tissue, Lucia A. De Jesus, Suzy D. Carvalho, Mirian O. Ribeiro, Mark Schneider, Sung-Woo Kim, John W. Harney, P. Reed Larsen, Antonio C. Bianco Nov 2001

The Type 2 Iodothyronine Deiodinase Is Essential For Adaptive Thermogenesis In Brown Adipose Tissue, Lucia A. De Jesus, Suzy D. Carvalho, Mirian O. Ribeiro, Mark Schneider, Sung-Woo Kim, John W. Harney, P. Reed Larsen, Antonio C. Bianco

Dartmouth Scholarship

Type 2 iodothyronine deiodinase (D2) is a selenoenzyme, the product of the recently cloned cAMP-dependent Dio2 gene, which increases 10- to 50-fold during cold stress only in brown adipose tissue (BAT). Here we report that despite a normal plasma 3,5,3′-triiodothyronine (T3) concentration, cold-exposed mice with targeted disruption of the Dio2 gene (Dio2–/–) become hypothermic due to impaired BAT thermogenesis and survive by compensatory shivering with consequent acute weight loss. This occurs despite normal basal mitochondrial uncoupling protein 1 (UCP1) concentration. In Dio2–/– brown adipocytes, the acute norepinephrine-, CL316,243-, or forskolin-induced increases in lipolysis, UCP1 mRNA, and …


Distinct Retrieval And Retention Mechanisms Are Required For The Quality Control Of Endoplasmic Reticulum Protein Folding, Shilpa Vashist, Woong Kim, William J. Belden, Eric D. Spear, Charles Barlowe, Davis T.W. Ng Oct 2001

Distinct Retrieval And Retention Mechanisms Are Required For The Quality Control Of Endoplasmic Reticulum Protein Folding, Shilpa Vashist, Woong Kim, William J. Belden, Eric D. Spear, Charles Barlowe, Davis T.W. Ng

Dartmouth Scholarship

Proteins destined for the secretory pathway must first fold and assemble in the lumen of endoplasmic reticulum (ER). The pathway maintains a quality control mechanism to assure that aberrantly processed proteins are not delivered to their sites of function. As part of this mechanism, misfolded proteins are returned to the cytosol via the ER protein translocation pore where they are ubiquitinated and degraded by the 26S proteasome. Previously, little was known regarding the recognition and targeting of proteins before degradation. By tracking the fate of several mutant proteins subject to quality control, we demonstrate the existence of two distinct sorting …


The Cataclysmic Variable Cw 1045+525: A Secondary-Dominated Dwarf Nova?, C. Tappert, J. R. Thorstensen, W. H. Fenton, N. Bennert Oct 2001

The Cataclysmic Variable Cw 1045+525: A Secondary-Dominated Dwarf Nova?, C. Tappert, J. R. Thorstensen, W. H. Fenton, N. Bennert

Dartmouth Scholarship

We present spectroscopic and photometric observations of the cataclysmic variable CW 1045+525. Both the optical spectrum and the photometric lightcurve show a strong contribution of a K5V–M0V secondary. We derive an orbital period Porb = 0.271278(1) d by measuring the radial velocities of the absorption lines of the secondary. The period and spectral type of the secondary suggest a distance of 350–700 pc. There is evidence for additional sources of line- and continuum emission, but no direct evidence of an accretion disc. We discuss several scenarios for the nature of CW 1045+525 on the basis of our results, finding a …


Solar: Towards A Flexible And Scalable Data-Fusion Infrastructure For Ubiquitous Computing, Guanling Chen, David Kotz Oct 2001

Solar: Towards A Flexible And Scalable Data-Fusion Infrastructure For Ubiquitous Computing, Guanling Chen, David Kotz

Dartmouth Scholarship

As we embed more computers into our daily environment, ubiquitous computing promises to make them less noticeable and to avoid information overload. We see, however, few ubiquitous applications that are able to adapt to the dynamics of user, physical, and computational context. The challenge is to allow applications flexible access to these sources, and yet scale to thousands of devices and sensors. In this paper we introduce our proposed infrastructure, Solar. In Solar, information sources produce events. Applications may subscribe to interesting sources directly, or they may instantiate and subscribe to a tree of operators that filter, transform, merge and …


Spectroscopy And Orbital Periods Of Four Cataclysmic Variable Stars, John R. Thorstensen, Cynthia J. Taylor Oct 2001

Spectroscopy And Orbital Periods Of Four Cataclysmic Variable Stars, John R. Thorstensen, Cynthia J. Taylor

Dartmouth Scholarship

We present spectroscopy and orbital periods Porb of four relatively little-studied cataclysmic variable stars. The stars and their periods are: AF Cam, Porb = 0.324(1) d (the daily cycle count is slightly ambiguous); V2069 Cyg (= RX J2123.7+4217), 0.311683(2) d; PG 0935+075, 0.1868(3) d; and KUV 03580+0614, 0.1495(6) d. V2069 Cyg and KUV 03580+0614 both show He iiλ4686 emission comparable in strength to Hβ. V2069 Cyg appears to be a luminous nova-like variable, and the strong He ii suggests it may be an intermediate polar. The period of KUV 03580+0614 is similar to members …


Comparing The Sfi Peculiar Velocities With The Pscz Gravity Field: A Velmod Analysis, E. Branchini, W. Freudling, L. N. Da Costa, C. S. Frenk, R. Giovanelli, M. P. Haynes, J. J. Salzer, G. Wegner, I. Zehavi Sep 2001

Comparing The Sfi Peculiar Velocities With The Pscz Gravity Field: A Velmod Analysis, E. Branchini, W. Freudling, L. N. Da Costa, C. S. Frenk, R. Giovanelli, M. P. Haynes, J. J. Salzer, G. Wegner, I. Zehavi

Dartmouth Scholarship

We compare the peculiar velocities derived from the I-band Tully–Fisher (TF) relation for 989 field spiral galaxies in the SFI catalogue with the predicted velocity field derived from the IRAS PSCz galaxy redshift survey. We assume linear gravitational instability theory and apply the maximum likelihood technique, VELMOD to SFI galaxies within a redshift cz LG =6000 km s−1. The resulting calibration of the TF relation is consistent with a previous, independent calibration for a similar sample of spirals residing in clusters. Our analysis provides an accurate estimate of the quantity βI ≡ Ωm0.6 …


The Chromokinesin Kid Is Necessary For Chromosome Arm Orientation And Oscillation, But Not Congression, On Mitotic Spindles, Aime A. Levesque, Duane A. Compton Sep 2001

The Chromokinesin Kid Is Necessary For Chromosome Arm Orientation And Oscillation, But Not Congression, On Mitotic Spindles, Aime A. Levesque, Duane A. Compton

Dartmouth Scholarship

Chromokinesins have been postulated to provide the polar ejection force needed for chromosome congression during mitosis. We have evaluated that possibility by monitoring chromosome movement in vertebrate-cultured cells using time-lapse differential interference contrast microscopy after microinjection with antibodies specific for the chromokinesin Kid. 17.5% of cells injected with Kid-specific antibodies have one or more chromosomes that remain closely opposed to a spindle pole and fail to enter anaphase. In contrast, 82.5% of injected cells align chromosomes in metaphase, progress to anaphase, and display chromosome velocities not significantly different from control cells. However, injected cells lack chromosome oscillations, and chromosome orientation …


What Accounts For The Variation In Retirement Wealth Among U.S. Households?, B. Douglas Bernheim, Jonathan Skinner, Steven Weinberg Sep 2001

What Accounts For The Variation In Retirement Wealth Among U.S. Households?, B. Douglas Bernheim, Jonathan Skinner, Steven Weinberg

Dartmouth Scholarship

Even among households with similar socioeconomic characteristics, saving and wealth vary considerably. Life-cycle models attribute this variation to differences in time preference rates, risk tolerance, exposure to uncertainty, relative tastes for work and leisure at advanced ages, and income replacement rates. These factors have testable implications concerning the relation between accumulated wealth and the shape of the consumption profile. Using the Panel Study of Income Dynamics and the Consumer Expenditure Survey, we find little support for these implications. The data are instead consistent with "rule of thumb," "mental accounting," or hyperbolic discounting theories of wealth accumulation.


Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner Sep 2001

Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner

Dartmouth Scholarship

We estimate the mass density fluctuations power spectrum (PS) on large scales by applying a maximum likelihood technique to the peculiar velocity data of the recently completed redshift—distance survey of early-type galaxies (hereafter ENEAR). Parametric cold dark matter (CDM)-like models for the PS are assumed, and the best-fitting parameters are determined by maximizing the probability of the model given the measured peculiar velocities of the galaxies, their distances and estimated errors. The method has been applied to CDM models with and without COBE normalization. The general results are in agreement with the high-amplitude power spectra found from similar analyses of …


Grb 010222: A Burst Within A Starburst, D. A. Frail, F. Bertoldi, G. H. Moriarty‐Schieven, E. Berger, P. A. Price, J. S. Bloom, R. Sari, S. R. Kulkarni, C. L. Gerardy, D. E. Reichart Aug 2001

Grb 010222: A Burst Within A Starburst, D. A. Frail, F. Bertoldi, G. H. Moriarty‐Schieven, E. Berger, P. A. Price, J. S. Bloom, R. Sari, S. R. Kulkarni, C. L. Gerardy, D. E. Reichart

Dartmouth Scholarship

We present millimeter and submillimeter wavelength observations and near-infrared K -band imaging toward the bright gamma-ray burst GRB 010222. Over seven epochs the flux density of the source was constant wit h an average flux density 3.74 ± 0.53 mJy at 350 GHz and 1.05 ± 0.22 mJy at 250 GHz, giving a spectral index α = 3 . 78 ± 0.25 (where F∝ να). We rule out the possibility that this emission originated from the burst or its afterglow and we conclu de that it is due to a dusty, high redshift starburst galaxy (SMM J14522+43 01). …


Redshifts For 2410 Galaxies In The Century Survey Region, Gary Wegner, John R. Thorstensen, Michael J. Kurtz, Warren R. Brown, Daniel G. Fabricant, Margaret J. Geller, John P. Huchra, Ronald O. Marzke, Shoko Sakai Aug 2001

Redshifts For 2410 Galaxies In The Century Survey Region, Gary Wegner, John R. Thorstensen, Michael J. Kurtz, Warren R. Brown, Daniel G. Fabricant, Margaret J. Geller, John P. Huchra, Ronald O. Marzke, Shoko Sakai

Dartmouth Scholarship

The Century Survey strip covers 102 deg2 within the limits 85 ≤ α ≤ 165, 290 ≤ δ ≤ 300, equinox B1950.0. The strip passes through the Corona Borealis supercluster and the outer region of the Coma cluster. Within the Century Survey region, we have measured 2410 redshifts that constitute four overlapping complete redshift surveys: (1) 1728 galaxies with Kron-Cousins Rph ≤ 16.13 covering the entire strip, (2) 507 galaxies with Rph ≤ 16.4 in right ascension range 8h32m ≤ α ≤ 10 h45m, equinox B1950.0, (3) 1251 galaxies with absorption- …


The Nature Of [Ar Iii]-Bright Knots In The Crab Nebula, Emily L. Schaller, Robert A. Fesen Aug 2001

The Nature Of [Ar Iii]-Bright Knots In The Crab Nebula, Emily L. Schaller, Robert A. Fesen

Dartmouth Scholarship

The kinematic and morphological properties of a string of [Ar III] bright knots in the CrabNebula are examined using 1994 – 1999 HST WFPC-2 images of the remnant. We find that five southern [Ar III] bright knots exhibit ordinary radial motions away from the nebula’s center of expansion with magnitudes consistent with their projected radial displacements. This result does not support the suggestion by MacAlpine et al. (1994) that these knots might be moving rapidly away from the Crab pulsar due to a collimated wind. The HST images also do not show that the [Ar III] knots have unusual morphologies …


Heavy‐Element Diffusion In Metal‐Poor Stars, Brian Chaboyer, W. H. Fenton, Jenica E. Nelan, D. J. Patnaude, Francesca E. Simon Aug 2001

Heavy‐Element Diffusion In Metal‐Poor Stars, Brian Chaboyer, W. H. Fenton, Jenica E. Nelan, D. J. Patnaude, Francesca E. Simon

Dartmouth Scholarship

Stellar evolution models that include the effect of helium and heavy-element diffusion have been calculated for initial iron abundances of [Fe/H] = -2.3, -2.1, -1.9, and -1.7. These models were calculated for a large variety of masses and three separate mixing lengths, α = 1.50, 1.75, and 2.00 (with α = 1.75 being the solar calibrated mixing length). The change in the surface iron abundance for stars of different masses was determined for the ages of 11, 13, and 15 Gyr. Iron settles out of the surface convection zone on the main sequence ; this iron is dredged back up …


Phylogenetic Relationships Within Cation Transporter Families Of Arabidopsis, Pascal Mäser, Sébastien Thomine, Julian I. Schroeder, John M. Ward, Kendal Hirschi, Heven Sze, Ina N. Talke, Anna Amtmann, Frans J.M. Maathuis, Dale Sanders, Jeff F. Harper, Jason Tchieu, Michael Gribskov, Michael W. Persans, David E. Salt, Sun A. Kim, Mary Lou Guerinot Aug 2001

Phylogenetic Relationships Within Cation Transporter Families Of Arabidopsis, Pascal Mäser, Sébastien Thomine, Julian I. Schroeder, John M. Ward, Kendal Hirschi, Heven Sze, Ina N. Talke, Anna Amtmann, Frans J.M. Maathuis, Dale Sanders, Jeff F. Harper, Jason Tchieu, Michael Gribskov, Michael W. Persans, David E. Salt, Sun A. Kim, Mary Lou Guerinot

Dartmouth Scholarship

Uptake and translocation of cationic nutrients play essential roles in physiological processes including plant growth, nutrition, signal transduction, and development. Approximately 5% of the Arabidopsis genome appears to encode membrane transport proteins. These proteins are classified in 46 unique families containing approximately 880 members. In addition, several hundred putative transporters have not yet been assigned to families. In this paper, we have analyzed the phylogenetic relationships of over 150 cation transport proteins. This analysis has focused on cation transporter gene families for which initial characterizations have been achieved for individual members, including potassium transporters and channels, sodium transporters, calcium antiporters, …


Sart, A Repressor Of Α-Hemolysin In Staphylococcus Aureus, Katherine A. Schmidt, Adhar C. Manna, Steven Gill, Ambrose L. Cheung Aug 2001

Sart, A Repressor Of Α-Hemolysin In Staphylococcus Aureus, Katherine A. Schmidt, Adhar C. Manna, Steven Gill, Ambrose L. Cheung

Dartmouth Scholarship

In searching the Staphylococcus aureus genome, we found several homologs to SarA. One of these genes, sarT, codes for a basic protein with 118 residues and a predicted molecular size of 16,096 Da. Northern blot analysis revealed that the expression of sarT was repressed by sarA and agr. An insertion sarT mutant generated in S. aureus RN6390 and 8325-4 backgrounds revealed minimal effect on the expression of sarR and sarA. The RNAIII level was notably increased in the sarT mutant, particularly in postexponential-phase cells, while the augmentative effect on RNAII was less. SarT repressed the expression of alpha-hemolysin, as determined …


Stellar Pollution In The Solar Neighborhood, N. Murray, B. Chaboyer, P. Arras, B. Hansen, R. W. Noyes Jul 2001

Stellar Pollution In The Solar Neighborhood, N. Murray, B. Chaboyer, P. Arras, B. Hansen, R. W. Noyes

Dartmouth Scholarship

We study spectroscopically determined iron abundances of 640 solar-type stars to search for the signature of accreted iron-rich material. We find that the metallicity [Fe/H] of a subset of 466 main-sequence stars, when plotted as a function of stellar mass, mimics the pattern seen in lithium abundances in open clusters. Using Monte Carlo models, we find that, on average, these stars appear to have accreted ~0.5 M⊕ of iron while on the main-sequence. A consistency check is provided by a much smaller sample of 19 stars in the Hertzsprung gap, which are slightly evolved and the convection zones of …