494 research outputs found
The Effect of Recruitment Messages on Undergraduate Beliefs about the Communication Major: A Quasi-Experiment
Despite the importance of attracting talented and qualified undergraduates into the major, the subject of recruitment for communication has received little attention. This study examines the effectiveness of a one-shot informative recruitment message on studentsâ beliefs and attitudes toward the communication major. As part of a quasi-experiment using a Solomon four-group design, two upper-division majors presented recruitment presentations addressing the benefits of, and misconceptions toward, the major to 130 students enrolled in introductory public speaking classes. Post-tests revealed that students exposed to the message reported significantly more favorable attitudes toward communication than those who had not seen a presentation (n = 65). Belief in the value of communication skills was also found positively associated with attitude toward the major, while belief that communication skills are innate was negatively associated with major attitude. Limitations and practical implications of this study are discussed as well
Critical Communication Pedagogy in/about/through the Communication Classroom
Critical Communication Pedagogy (CCP) signals a critical approach to Communication and Instruction scholarship. Critical signals a recognition that social reality is inherently political and encourages individuals to work with/in communities to identify, intervene into, and change oppressive systems. Communication and Instruction scholarship refers to (a) research concerning how to teach communication principles, theories, or knowledge (i.e., Communication Pedagogy or Communication Education) and (b) research about communication as it manifests in or about all types of educational spaces (i.e., Instructional Communication). CCP is not guided by a single methodology; rather, it signifies both an intellectual tradition and an umbrella term for critical approaches to Communication Pedagogy and Instructional Communication
The Burrell-Optical-Kepler-Survey (BOKS). I. Survey Description and Initial Results
We present the initial results of a 40 night contiguous ground-based campaign of time series photometric observations of a 1.39 deg^2 field located within the NASA Kepler Mission field of view. The goal of this pre-launch survey was to search for transiting extrasolar planets and to provide independent variability information of stellar sources. We have gathered a data set containing light curves of 54,687 stars from which we have created a statistical sub-sample of 13,786 stars between 14 < r < 18.5 and have statistically examined each light curve to test for variability. We present a summary of our preliminary photometric findings including the overall level and content of stellar variability in this portion of the Kepler field and give some examples of unusual variable stars found within. We present a preliminary catalog of 2,457 candidate variable stars, of which 776 show signs of periodicity. We also present three potential exoplanet candidates, all of which should be observable by the Kepler mission
Diffuse light and galaxy interactions in the core of nearby clusters
The kinematics of the diffuse light in the densest regions of the nearby
clusters can be unmasked using the planetary nebulae (PNs) as probes of the
stellar motions. The position-velocity diagrams around the brightest cluster
galaxies (BCGs) identify the relative contributions from the outer halos and
the intracluster light (ICL), defined as the light radiated by the stars
floating in the cluster potential. The kinematics of the ICL can then be used
to asses the dynamical status of the nearby cluster cores and to infer their
formation histories. The cores of the Virgo and Coma are observed to be far
from equilibrium, with mergers currently on-going, while the ICL properties in
the Fornax and Hydra clusters show the presence of sub-components being
accreted in their cores, but superposed to an otherwise relaxed population of
stars. Finally the comparison of the observed ICL properties with those
predicted from Lambda-CDM simulations indicates a qualitative agreement and
provides insights on the ICL formation. Both observations and simulations
indicate that BCG halos and ICL are physically distinct components, with the
``hotter" ICL dominating at large radial distances from the BCGs halos as the
latter become progressively fainter.Comment: 14 pages, 5 figures. Invited review to appear in the proceedings of
"Galaxies and their masks" eds. Block, D.L., Freeman, K.C. and Puerari, I.,
2010, Springer (New York
Intragroup diffuse light in compact groups of galaxies II. HCG 15, 35 and 51
This continuing study of intragroup light in compact groups of galaxies aims
to establish new constraints to models of formation and evolution of galaxy
groups, specially of compact groups, which are a key part in the evolution of
larger structures, such as clusters. In this paper we present three additional
groups (HCG 15, 35 and 51) using deep wide field and band images
observed with the LAICA camera at the 3.5m telescope at the Calar Alto
observatory (CAHA). This instrument provides us with very stable flatfielding,
a mandatory condition for reliably measuring intragroup diffuse light. The
images were analyzed with the OV\_WAV package, a wavelet technique that allows
us to uncover the intragroup component in an unprecedented way. We have
detected that 19, 15 and 26% of the total light of HCG 15, 35 and 51,
respectively, is in the diffuse component, with colours that are compatible
with old stellar populations and with mean surface brightness that can be as
low as . Dynamical masses, crossing times and
mass to light ratios were recalculated using the new group parameters. Also
tidal features were analyzed using the wavelet technique.Comment: 12 pages, 5 figures. Accepted for publication in MNRAS. See
http://www.eso.org/~cdarocha/publications/DaRochaetal2008_IGL_HCG.pdf for
full resolution version. Complementary reference adde
Natalizumab affects T-cell phenotype in multiple sclerosis: implications for JCV reactivation
The anti-CD49d monoclonal antibody natalizumab is currently an effective therapy against the relapsing-remitting form of multiple sclerosis (RRMS). Natalizumab therapeutic efficacy is limited by the reactivation of the John Cunningham polyomavirus (JCV) and development of progressive multifocal leukoencephalopathy (PML). To correlate natalizumab-induced phenotypic modifications of peripheral blood T-lymphocytes with JCV reactivation, JCV-specific antibodies (serum), JCV-DNA (blood and urine), CD49d expression and relative abundance of peripheral blood T-lymphocyte subsets were longitudinally assessed in 26 natalizumab-treated RRMS patients. Statistical analyses were performed using GraphPad Prism and R. Natalizumab treatment reduced CD49d expression on memory and effector subsets of peripheral blood T-lymphocytes. Moreover, accumulation of peripheral blood CD8+ memory and effector cells was observed after 12 and 24 months of treatment. CD4+ and CD8+ T-lymphocyte immune-activation was increased after 24 months of treatment. Higher percentages of CD8+ effectors were observed in subjects with detectable JCV-DNA. Natalizumab reduces CD49d expression on CD8+ T-lymphocyte memory and effector subsets, limiting their migration to the central nervous system and determining their accumulation in peripheral blood. Impairment of central nervous system immune surveillance and reactivation of latent JCV, can explain the increased risk of PML development in natalizumab-treated RRMS subjects
Two formation channels of UCDs in Hickson Compact Groups
The formation of ultra-compact dwarf galaxies (UCDs) is believed to be
interaction driven, and UCDs are abundant in the cores of galaxy clusters,
environments that mark the end-point of galaxy evolution. Nothing is known
about the properties of UCDs in compact groups of galaxies, environments where
most of galaxy evolution and interaction is believed to occur and where UCDs in
intermediate state of evolution may be expected. The main goal of this study is
to detect and characterize, for the first time, the UCD population of compact
groups. For that, 2 groups in different evolutionary stages, HCG 22 and HCG 90,
were targeted with VLT/FORS2/MXU. We detect 16 and 5 objects belonging to HCG
22 and HCG 90, respectively, covering the magnitude range -10.0 > M_R > -11.5
mag. Their colours are consistent with old ages covering a broad range in
metallicities. Photometric mass estimates put 4 objects in HCG 90 and 9 in HCG
22 in the mass range of UCDs (>2x10^6 M_Sun) for an assumed age of 12 Gyr.
These UCDs are on average 2-3 times larger than typical Galactic GCs, covering
a range of 2 >~ r_h >~ 21 pc. The UCDs in HCG 22 are more concentrated around
the central galaxy than in HCG 90, at the 99% confidence level. They cover a
broad range in [alpha/Fe] abundances from sub- to super-solar. The spectra of 3
UCDs show tentative evidence for intermediate age stellar populations. We
calculate the specific frequency (S_N) of UCDs for both groups, finding that
HCG 22 has about three times higher S_N than HCG 90. The ensemble properties of
the detected UCDs supports 2 co-existing formation channels: a star cluster
origin and an origin as tidally stripped dwarf nuclei. Our results imply that
the UCDs detected in both groups do not, in their majority, originate from
relatively recent galaxy interactions. Most of the detected UCDs have likely
been brought into the group with their host galaxies.[abridged]Comment: Accepted for publication at A&A, 17 pages, 9 figures + 2 additional
figure
Metal enrichment processes
There are many processes that can transport gas from the galaxies to their
environment and enrich the environment in this way with metals. These metal
enrichment processes have a large influence on the evolution of both the
galaxies and their environment. Various processes can contribute to the gas
transfer: ram-pressure stripping, galactic winds, AGN outflows, galaxy-galaxy
interactions and others. We review their observational evidence, corresponding
simulations, their efficiencies, and their time scales as far as they are known
to date. It seems that all processes can contribute to the enrichment. There is
not a single process that always dominates the enrichment, because the
efficiencies of the processes vary strongly with galaxy and environmental
properties.Comment: 18 pages, 8 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 17; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
Cost of managing an episode of relapse in multiple sclerosis in the United States
BACKGROUND: The purpose of this study was to determine the direct medical US cost of managing multiple sclerosis relapses. METHODS: Direct data analysis and cost modeling were employed to derive typical resource use profiles and costs in 2002 US dollars, from the perspective of a third-party payer responsible for comprehensive health-care. The location and scope of health care services provided over a 90-day period were used to define three levels of relapse management. Hospitalization and resulting subsequent care was defined as high intensity management. A medium level of intervention was defined as either use of the emergency room, an observational unit, or administration of acute treatments, such as intravenous methylprednisolone in an outpatient or home setting. The lowest intensity of care comprised physician office visits and symptom-related medications. Data were obtained from many sources including all payer inpatient, ambulatory and emergency room databases from several states, fee schedules, government reports, and literature. All charges were adjusted using cost-to-charge ratios. RESULTS: Average cost per person for high management level was 1,847 and mild episode $243. CONCLUSIONS: Management strategies leading to a reduction in the frequency and severity of a relapse, less reliance on inpatient care, or increased access to steroid infusions in the home, would have a substantial impact on the economic consequences of managing relapses
RecomendaçÔes quanto ao uso de drogas imunomoduladoras na esclerose mĂșltipla: o consenso do BCTRIMS
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