4,511 research outputs found
The CREATE Approach to Primary Literature Shifts Undergraduates' Self-Assessed Ability to Read and Analyze Journal Articles, Attitudes about Science, and Epistemological Beliefs
The C. R. E. A. T. E. (Consider, Read, Elucidate hypotheses, Analyze and interpret data, Think of the next Experiment) method uses intensive analysis of primary literature in the undergraduate classroom to demystify and humanize science. We have reported previously that the method improves students' critical thinking and content integration abilities, while at the same time enhancing their self-reported understanding of "who does science, and why." We report here the results of an assessment that addressed C. R. E. A. T. E. students' attitudes about the nature of science, beliefs about learning, and confidence in their ability to read, analyze, and explain research articles. Using a Likert-style survey administered pre- and postcourse, we found significant changes in students' confidence in their ability to read and analyze primary literature, self-assessed understanding of the nature of science, and epistemological beliefs (e. g., their sense of whether knowledge is certain and scientific talent innate). Thus, within a single semester, the inexpensive C. R. E. A. T. E. method can shift not just students' analytical abilities and understanding of scientists as people, but can also positively affect students' confidence with analysis of primary literature, their insight into the processes of science, and their beliefs about learning.NSFNSF CCLI/TUES 0311117, 0618536, 1021443Molecular Bioscience
Galaxies in Clusters: the Observational Characteristics of Bow-Shocks, Wakes and Tails
The dynamical signatures of the interaction between galaxies in clusters and
the intracluster medium (ICM) can potentially yield significant information
about the structure and dynamical history of clusters. To develop our
understanding of this phenomenon we present results from numerical modelling of
the galaxy/ICM interaction, as the galaxy moves through the cluster. The
simulations have been performed for a broad range, of ICM temperatures (kT =
1,4 and 8 keV), representative of poor clusters or groups through to rich
clusters. There are several dynamical features that can be identified in these
simulations; for supersonic galaxy motion, a leading bow-shock is present, and
also a weak gravitationally focussed wake or tail behind the galaxy (analogous
to Bondi-Hoyle accretion). For galaxies with higher mass-replenishment rates
and a denser interstellar medium (ISM), the dominant feature is a dense
ram-pressure stripped tail. In line with other simulations, we find that the
ICM/galaxy ISM interaction can result in complex time- dependent dynamics, with
ram-pressure stripping occurring in an episodic manner. In order to facilitate
this comparison between the observational consequences of dynamical studies and
X-ray observations we have calculated synthetic X-ray flux and hardness maps
from these simulations. These calculations predict that the ram-pressure
stripped tail will usually be the most visible feature, though in nearby
galaxies the bow-shock preceding the galaxy should also be apparent in deeper
X-ray observations. We briefly discuss these results and compare with X-ray
observations of galaxies where there is evidence of such interactions.Comment: 14 pages, 8 diagrams, MNRAS (in press
Children’s Health Care: Health Information Technology and Electronic Health Records
The panel addressed: Why pediatric electronic health records are different from adult EHRs; How HIT/EHRs can be helpful in the area of prevention with pediatric populations; How using HIT/EHRs can help improve quality and outcome measures for children and underserved communities; Barriers to getting HIT/EHRs into underserved communities and ways to overcome these challenges; Opportunities for stimulus funds to support HIT access for underserved pediatric populations; and Privacy and confidetiality concerns regarding pediatric EHRs
Simulations of the Effects of Stripping and Accretion on Galaxy Haloes in Clusters
We present results from a series of hydrodynamic simulations investigating
ram pressure stripping of galactic haloes as the host galaxy falls radially
into a cluster. We perform a parameter study comprising of variations in
initial gas content, gas injection rate (via stellar mass loss processes),
galaxy mass and amplitude of infall. From the simulation results we track
variations in both physical quantities (e.g. gas mass) and directly observable
quantities (e.g. X-ray luminosities). The luminosity of the galaxy's X-ray halo
is found to compare favourably with the observationally determined correlation
with optical blue band luminosity (L_X:L_B) relation. Factors affecting the
X-ray luminosity are explored and it is found that the gas injection rate is a
dominant factor in determining the integrated luminosity. Observational
properties of the material stripped from the galaxy, which forms an X-ray wake,
are investigated and it is found that wakes are most visible around galaxies
with a substantial initial gas content, during their first passage though the
cluster. We define a statistical skewness measure which may be used to
determine the direction of motion of a galaxy using X-ray observations.
Structures formed in these simulations are similar to the cold fronts seen in
observation of cluster mergers where a sharp increase in surface brightness is
accompanied by a transition to a cooler region.Comment: Accepted for publication in MNRAS. 19 pages, 21 figure
Chandra and XMM-Newton Observations of NGC 4214: The Hot Interstellar Medium and the Luminosity Function of Dwarf Starbursts
We present results from Chandra and XMM-Newton X-ray observations of NGC
4214, a nearby dwarf starburst galaxy containing several young regions of very
active star-formation. Starburst regions are known to be associated with
diffuse X-ray emission, and in this case the X-ray emission from the galaxy
shows an interesting morphological structure within the galaxy, clearly
associated with the central regions of active star-formation. Of the two main
regions of star-formation in this galaxy, X-ray emission associated with the
older is identified whereas little is detected from the younger, providing an
insight into the evolutionary process of the formation of superbubbles around
young stellar clusters. The spectra of the diffuse emission from the galaxy can
be fitted with a two temperature component thermal model with kT=0.14keV and
0.52keV, and analysis of this emission suggests that NGC 4214 will suffer a
blow-out in the future.
The point source population of the galaxy has an X-ray luminosity function
with a slope of -0.76. This result, together with those for other dwarf
starburst galaxies (NGC 4449 and NGC 5253), was added to a sample of luminosity
functions for spiral and starburst galaxies. The slope of the luminosity
function of dwarf starbursts is seen to be similar to that of their larger
counterparts and clearly flatter than those seen in spirals. Further
comparisons between the luminosity functions of starbursts and spiral galaxies
are also made.Comment: 16 pages, 12 figures. Accepted for publication in MNRA
Incorporation of SemiSpan SuperSonic Transport (S4T) Aeroservoelastic Models into SAREC-ASV Simulation
The Simulink-based Simulation Architecture for Evaluating Controls for Aerospace Vehicles (SAREC-ASV) was modified to incorporate linear models representing aeroservoelastic characteristics of the SemiSpan SuperSonic Transport (S4T) wind-tunnel model. The S4T planform is for a Technology Concept Aircraft (TCA) design from the 1990s. The model has three control surfaces and is instrumented with accelerometers and strain gauges. Control laws developed for wind-tunnel testing for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression System functions were implemented in the simulation. The simulation models open- and closed-loop response to turbulence and to control excitation. It provides time histories for closed-loop stable conditions above the open-loop flutter boundary. The simulation is useful for assessing the potential impact of closed-loop control rate and position saturation. It also provides a means to assess fidelity of system identification procedures by providing time histories for a known plant model, with and without unmeasured turbulence as a disturbance. Sets of linear models representing different Mach number and dynamic pressure conditions were implemented as MATLAB Linear Time Invariant (LTI) objects. Configuration changes were implemented by selecting which LTI object to use in a Simulink template block. A limited comparison of simulation versus wind-tunnel results is shown
Discounting and Reciprocity in an Iterated Prisoner’s Dilemma
The Iterated Prisoner’s Dilemma (IPD) is a central paradigm in the study of animal cooperation. According to the IPD framework, repeated play (repetition) and reciprocity combine to maintain a cooperative equilibrium. However, experimental studies with animals suggest that cooperative behavior in IPDs is unstable, and some have suggested that strong preferences for immediate benefits (that is, temporal discounting) might explain the fragility of cooperative equilibria. We studied the effects of discounting and strategic reciprocity on cooperation in captive blue jays. Our results demonstrate an interaction between discounting and reciprocity. Blue jays show high stable levels of cooperation in treatments with reduced discounting when their opponent reciprocates, but their levels of cooperation decline in all other treatment combinations. This suggests that stable cooperation requires both reduced discounting and reciprocity, and it offers an explanation of earlier failures to find cooperation in controlled payoff games
mTOR Complex 2 Is Required for the Development of Prostate Cancer Induced by Pten Loss in Mice
mTOR complex 2 (mTORC2) contains the mammalian target of rapamycin (mTOR) kinase and the Rictor regulatory protein and phosphorylates Akt. Whether this function of mTORC2 is critical for cancer progression is unknown. Here, we show that transformed human prostate epithelial cells lacking PTEN require mTORC2 to form tumors when injected into nude mice. Furthermore, we find that Rictor is a haploinsufficient gene and that deleting one copy protects Pten heterozygous mice from prostate cancer. Finally, we show that the development of prostate cancer caused by Pten deletion specifically in prostate epithelium requires mTORC2, but that for normal prostate epithelial cells, mTORC2 activity is nonessential. The selective requirement for mTORC2 in tumor development suggests that mTORC2 inhibitors may be of substantial clinical utility.W. M. Keck FoundationDamon Runyon Cancer Research Foundation (Research Fellowship)Leukemia & Lymphoma Society of America (Career Development Award)Howard Hughes Medical Institute (Investigator)National Institutes of Health (U.S.) (K99 CA1296613-01A1)National Institutes of Health (U.S.) (R01 CA107166)National Institutes of Health (U.S.) (R01 AI04389)National Institutes of Health (U.S.) (R01 CA103866
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