892 research outputs found
Graded exercises in visual discrimination
Thesis (M.A.)--Boston University, 1949. This item was digitized by the Internet Archive
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Parental Serotonin Transporter Polymorphism (5-HTTLPR) Moderates Associations of Stress and Child Behavior With Parenting Behavior.
The serotonin transporter-linked polymorphic region (5-HTTLPR) is associated with caregiving in nonhuman animals and with affective and cognitive correlates of human parenting, yet its association with human parenting is largely unknown. Using a well-characterized sample of parents and offspring, we evaluated the association of parental 5-HTTLPR with observed positive and negative parenting behavior, as well as its biologically plausible moderation of child-related stress and disruptive child behavior as predictors of parenting. One hundred and sixty-two parents (86% mothers) and their 6- to 9-year-old children with and without attention-deficit/hyperactivity disorder were ascertained using multiple methods including structured interviews, rating scales, and observed parent-child interaction, yielding strong measures of key constructs. Controlling for multiple youth-level (e.g., sex, 5-HTTLPR genotype, disruptive behavior) and parent-level (e.g., demographics, depression, attention-deficit/hyperactivity disorder) factors, parents with an S allele exhibited significantly less observed positive parenting than those with the LL genotype. Significant Gene Ă— Environment interactions were also observed: Child-related stress was negatively associated with observed parental negativity among SS/SL genotype parents but not LL genotype parents; next, observed disruptive child behavior was positively associated with parental negativity for both genotypes, but the effect was strongest in SS/SL parents. These preliminary findings suggest that parental 5-HTTLPR is uniquely associated with positive and negative parenting behavior, with more specific patterns according to child-related stress and disruptive child behavior. We consider implications for future research evaluating genetic influences on parenting as well as considerations for designing and delivering parenting-based interventions
Qualitative Study of International Business Associate's Degree Programs Delivered by United States Community Colleges
The United States has become internationalized. Government officials, education authorities and associates as well as the business community have solicited community colleges to provide the necessary knowledge and skills to students so they might achieve competence in the international business area. To date, only a relatively small number of community colleges have implemented an international business Associate's degree. In addition, educational researchers have requested the sharing of information on quality programs in international business. This study provides a listing of colleges offer the degree, surveys these colleges to provide information on facilitators and barriers to this program's implementation, gathers resources from these colleges, and provides a fuller description through site visits to four peer-nominated community colleges with quality international programs. Results of the survey provided information on the 22 community colleges which provided evidence of currently offering the program. It was determined that more than 20% of the colleges advertising these programs were, in fact, not delivering them. Primary barriers included inadequate structure, natural resistence to change, and inadequate funding; major facilitators were active participation of faculty, knowledgeable instructors with experience in international business, and, ideally, a full-time employee advocate for the program. The support of all levels of personnel at the community college is needed. The most common method of infusion is the injection of modules into existing courses; however, this has proved to deliver an insufficient body of knowledge, so advocated is the creation of new courses and/or an entire curriculum focused on international business. Characteristics of the quality programs include the support of the administration, active participation by faculty, instructors with working experience in the field, and students with diverse backgrounds in the program. This research identified a core curriculum to which each community college could add courses to fulfill one of the three program focuses depending on community demand-either general, trade, or cultural sensitivity. Resources and community college contacts for future providers of international business Associate's degree are included. Active partnerships with the business community were found at all quality site visits. Additionally, site-visit colleges started networking information. Few colleges knew anything about any other college delivering this program, and several stated that limited resources of time and money impeded program implementation and growth. In this electronic information age, consideration should be given to implementing an electronic exchange where information and experience could be shared.Occupational and Adult Educatio
Insight Into the Formation of the Milky Way Through Cold Halo Substructure. III. Statistical Chemical Tagging in the Smooth Halo
We find that the relative contribution of satellite galaxies accreted at high
redshift to the stellar population of the Milky Way's smooth halo increases
with distance, becoming observable relative to the classical smooth halo about
15 kpc from the Galactic center. In particular, we determine
line-of-sight-averaged [Fe/H] and [alpha/Fe] in the metal-poor main-sequence
turnoff (MPMSTO) population along every Sloan Extension for Galactic
Understanding and Exploration (SEGUE) spectroscopic line of sight. Restricting
our sample to those lines of sight along which we do not detect elements of
cold halo substructure (ECHOS), we compile the largest spectroscopic sample of
stars in the smooth component of the halo ever observed in situ beyond 10 kpc.
We find significant spatial autocorrelation in [Fe/H] in the MPMSTO population
in the distant half of our sample beyond about 15 kpc from the Galactic center.
Inside of 15 kpc however, we find no significant spatial autocorrelation in
[Fe/H]. At the same time, we perform SEGUE-like observations of N-body
simulations of Milky Way analog formation. While we find that halos formed
entirely by accreted satellite galaxies provide a poor match to our
observations of the halo within 15 kpc of the Galactic center, we do observe
spatial autocorrelation in [Fe/H] in the simulations at larger distances. This
observation is an example of statistical chemical tagging and indicates that
spatial autocorrelation in metallicity is a generic feature of stellar halos
formed from accreted satellite galaxies.Comment: 27 pages, 8 figures, and 7 tables in emulateapj format; accepted for
publication in ApJ. Full tables can be extracted from LaTeX sourc
Regulation of Collagenase Gene Expression by IL-1 Beta Requires Transcriptional and Post-Transcriptional Mechanisms
Interleukin-1 beta is believed to contribute to the pathophysiology of rheumatoid arthritis by activating collagenase gene expression. We have used a cell culture model of rabbit synovial fibroblasts to examine the molecular mechanisms of IL-1 beta-mediated collagenase gene expression. Stimulation of rabbit synovial fibroblasts with 10 ng/ml recombinant human IL-1 beta resulted in a 20-fold increase in collagenase mRNA by 12 h. Transient transfection studies using collagenase promoter-CAT constructs demonstrated that proximal sequences responded poorly to IL-1 beta, possibly due to insufficient activation of AP-1 by this cytokine. More distal sequences were required for IL-1 beta responsiveness, with a 4700 bp construct showing approximately 5-fold induction above control. To examine post-transcriptional mechanisms, transcript from a human collagenase cDNA was constitutively produced by the simian virus 40 early promoter. IL-1 beta stabilized the constitutively expressed human transcript. Furthermore, mutation of the ATTTA motifs in the 3\u27 untranslated region of the human gene also stabilized the transcript. Finally, the rabbit collagenase 3\u27 untranslated region destabilized a constitutively transcribed chloramphenicol acetyltransferase transcript. These data indicate that in addition to activating transcription, IL-1 beta increases collagenase transcript stability by reversing the destabilizing effects of sequences in the 3\u27 untranslated region
Metallicity Gradients in the Milky Way Disk as Observed by the SEGUE Survey
The observed radial and vertical metallicity distribution of old stars in the
Milky Way disk provides a powerful constraint on the chemical enrichment and
dynamical history of the disk. We present the radial metallicity gradient,
\Delta[Fe/H]/\Delta R, as a function of height above the plane, |Z|, using 7010
main sequence turnoff stars observed by the Sloan Extension for Galactic
Understanding and Exploration (SEGUE) survey. The sample consists of mostly old
thin and thick disk stars, with a minimal contribution from the stellar halo,
in the region 6 < R < 16 kpc, 0.15 < |Z| < 1.5 kpc. The data reveal that the
radial metallicity gradient becomes flat at heights |Z| > 1 kpc. The median
metallicity at large |Z| is consistent with the metallicities seen in outer
disk open clusters, which exhibit a flat radial gradient at [Fe/H] ~ -0.5. We
note that the outer disk clusters are also located at large |Z|; because the
flat gradient extends to small R for our sample, there is some ambiguity in
whether the observed trends for clusters are due to a change in R or |Z|. We
therefore stress the importance of considering both the radial and vertical
directions when measuring spatial abundance trends in the disk. The flattening
of the gradient at high |Z| also has implications on thick disk formation
scenarios, which predict different metallicity patterns in the thick disk. A
flat gradient, such as we observe, is predicted by a turbulent disk at high
redshift, but may also be consistent with radial migration, as long as mixing
is strong. We test our analysis methods using a mock catalog based on the model
of Sch\"onrich & Binney, and we estimate our distance errors to be ~25%. We
also show that we can properly correct for selection biases by assigning
weights to our targets.Comment: Submitted to ApJ; 22 pages, 14 figures in emulateapj format; Full
resolution version available at
http://www.ucolick.org/~jyc/gradient/cheng_apj_fullres.pd
Carbon-enhanced Metal-poor Stars in SDSS/SEGUE. I. Carbon Abundance Estimation and Frequency of CEMP Stars
We describe a method for the determination of stellar [C/Fe] abundance ratios
using low-resolution (R = 2000) stellar spectra from the SDSS and SEGUE. By
means of a star-by-star comparison with a set of SDSS/SEGUE spectra with
available estimates of [C/Fe] based on published high-resolution analyses, we
demonstrate that we can measure [C/Fe] from SDSS/SEGUE spectra with S/N > 15 to
a precision better than 0.35 dex. Using the measured carbon-to-iron abundance
ratios obtained by this technique, we derive the frequency of carbon-enhanced
stars ([C/Fe] > +0.7) as a function of [Fe/H], for both the SDSS/SEGUE stars
and other samples from the literature. We find that the differential frequency
slowly rises from almost zero to about 14% at [Fe/H] ~ -2.4, followed by a
sudden increase, by about a factor of three, to 39% from [Fe/H] ~ -2.4 to
[Fe/H] ~ -3.7. We also examine how the cumulative frequency of CEMP stars
varies across different luminosity classes. The giant sample exhibits a
cumulative CEMP frequency of 32% for [Fe/H] < -2.5, 31% for [Fe/H] < -3.0, and
33% for [Fe/H] < -3.5. For the main-sequence turnoff stars, we obtain a lower
cumulative CEMP frequency, around 10% for [Fe/H] < -2.5. The dwarf population
displays a large change in the cumulative frequency for CEMP stars below [Fe/H]
= -2.5, jumping from 15% for [Fe/H] < -2.5 to about 75% for [Fe/H] < -3.0. When
we impose a restriction with respect to distance from the Galactic mid-plane
(|Z| < 5 kpc), the frequency of the CEMP giants does not increase at low
metallicity ([Fe/H] < -2.5), but rather, decreases, due to the dilution of
C-rich material in stars that have undergone mixing with CNO-processed material
from their interiors. The frequency of CEMP stars near the main-sequence
turnoff, which are not expected to have experienced mixing, increases for
[Fe/H] < -3.0. [abridged]Comment: 19 pages, 10 figures, 6 tables, accepted for publication in AJ on
August 20, 201
Epithelial cell–derived secreted and transmembrane 1a signals to activated neutrophils during pneumococcal pneumonia
Airway epithelial cell responses are critical to the outcome of lung infection. In this study, we aimed to identify unique contributions of epithelial cells during lung infection. To differentiate genes induced selectively in epithelial cells during pneumonia, we compared genome-wide expression profiles from three sorted cell populations: epithelial cells from uninfected mouse lungs, epithelial cells from mouse lungs with pneumococcal pneumonia, and nonepithelial cells from those same infected lungs. Of 1,166 transcripts that were more abundant in epithelial cells from infected lungs compared with nonepithelial cells from the same lungs or from epithelial cells of uninfected lungs, 32 genes were identified as highly expressed secreted products. Especially strong signals included two related secreted and transmembrane (Sectm) 1 genes, Sectm1a and Sectm1b. Refinement of sorting strategies suggested that both Sectm1 products were induced predominantly in conducting airway epithelial cells. Sectm1 was induced during the early stages of pneumococcal pneumonia, and mutation of NF-kB RelA in epithelial cells did not diminish its expression. Instead, type I IFN signaling was necessary and sufficient for Sectm1 induction in lung epithelial cells, mediated by signal transducer and activator of transcription 1. For target cells, Sectm1a bound to myeloid cells preferentially, in particular Ly6GbrightCD11bbright neutrophils in the infected lung. In contrast, Sectm1a did not bind to neutrophils from uninfected lungs. Sectm1a increased expression of the neutrophil-attracting chemokine CXCL2 by neutrophils from the infected lung. We propose that Sectm1a is an epithelial product that sustains a positive feedback loop amplifying neutrophilic inflammation during pneumococcal pneumonia
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