4,285 research outputs found
AGN feedback at z~2 and the mutual evolution of active and inactive galaxies
The relationships between galaxies of intermediate stellar mass and moderate
luminosity active galactic nuclei (AGNs) at 1<z<3 are investigated with the
Galaxy Mass Assembly ultra-deep Spectroscopic Survey (GMASS) sample
complemented with public data in the GOODS-South field. Using X-ray data,
hidden AGNs are identified in unsuspected star-forming galaxies with no
apparent signs of non-stellar activity. In the color-mass plane, two parallel
trends emerge during the ~2 Gyr between the average redshifts z~2.2 and z~1.3:
while the red sequence becomes significantly more populated by ellipticals, the
majority of AGNs with L(2-10 keV)>10^42.3 erg s^-1 disappear from the blue
cloud/green valley where they were hosted predominantly by star-forming systems
with disk and irregular morphologies. These results are even clearer when the
rest-frame colors are corrected for dust reddening. At z~2.2, the ultraviolet
spectra of active galaxies (including two Type 1 AGNs) show possible gas
outflows with velocities up to about -500 km s^-1 that are not observed neither
in inactive systems at the same redshift, nor at lower redshifts. Such outflows
indicate the presence of gas that can move faster than the escape velocities of
active galaxies. These results suggest that feedback from moderately luminous
AGNs (logL_X~2 by contributing to
outflows capable of ejecting part of the interstellar medium and leading to a
rapid decrease in the star formation in host galaxies with stellar masses
10<logM<11 M_Sun.Comment: Astrophysical Journal Letters, in press (6 pages, 4 figures
Sustaining Educational Reforms in Introductory Physics
While it is well known which curricular practices can improve student
performance on measures of conceptual understanding, the sustaining of these
practices and the role of faculty members in implementing these practices are
less well understood. We present a study of the hand-off of Tutorials in
Introductory Physics from initial adopters to other instructors at the
University of Colorado, including traditional faculty not involved in physics
education research. The study examines the impact of implementation of
Tutorials on student conceptual learning across eight first-semester, and seven
second-semester courses, for fifteen faculty over twelve semesters, and
includes roughly 4000 students. It is possible to demonstrate consistently
high, and statistically indistinguishable, student learning gains for different
faculty members; however, such results are not the norm, and appear to rely on
a variety of factors. Student performance varies by faculty background -
faculty involved in, or informed by physics education research, consistently
post higher student learning gains than less-informed faculty. Student
performance in these courses also varies by curricula used - all semesters in
which the research-based Tutorials and Learning Assistants are used have higher
student learning gains than those semesters that rely on non-research based
materials and do not employ Learning Assistants.Comment: 21 pages, 4 figures, and other essential inf
Community empowerment and mental wellbeing: longitudinal findings from a survey of people actively involved in the big local place-based initiative in England
Background: Community empowerment initiatives are receiving increased interest as ways of improving health and reducing health inequalities. Purpose: Longitudinally examine associations between collective control, social-cohesion and mental wellbeing amongst participants in the Big Local community empowerment initiative across 150 disadvantaged areas of England. Methods: As part of the independent Communities in Control study, we analysed nested cohort survey data on mental wellbeing (Short Warwick Edinburgh Mental Wellbeing ScaleâSWEMWBS) and perceptions of collective control and social-cohesion. Data were obtained in 2016, 2018 and 2020 for 217 residents involved in the 150 Big Local areas in England. Adjusted linear mixed effect models were utilized to examine changes in SWEMWBS over the three waves. Subgroup analysis by gender and educational level was conducted. Results: There was a significant 1.46 (0.14, 2.77) unit increase in mental wellbeing score at wave 2 (2018) but not in wave 3 (2020) (0.06 [â1.41, 1.53]). Across all waves, collective control was associated with a significantly higher mental wellbeing score (3.36 [1.51, 5.21]) as was social cohesion (1.09 [0.19, 2.00]). Higher educated participants (1.99 [0.14, 3.84]) and men (2.41 [0.55, 4.28]) experienced significant increases in mental wellbeing in 2018, but lower educated participants and women did not. Conclusion: Collective control and social cohesion are associated with better mental wellbeing amongst residents engaged with the Big Local initiative. These health benefits were greater amongst men and participants from higher educational backgrounds. This suggests that additional care must be taken in future interventions to ensure that benefits are distributed equally
Convergence of the Optimized Delta Expansion for the Connected Vacuum Amplitude: Zero Dimensions
Recent proofs of the convergence of the linear delta expansion in zero and in
one dimensions have been limited to the analogue of the vacuum generating
functional in field theory. In zero dimensions it was shown that with an
appropriate, -dependent, choice of an optimizing parameter \l, which is an
important feature of the method, the sequence of approximants tends to
with an error proportional to . In the present paper we
establish the convergence of the linear delta expansion for the connected
vacuum function . We show that with the same choice of \l the
corresponding sequence tends to with an error proportional to . The rate of convergence of the latter sequence is governed by
the positions of the zeros of .Comment: 20 pages, LaTeX, Imperial/TP/92-93/5
Study protocol: asking questions about alcohol in pregnancy (AQUA): a longitudinal cohort study of fetal effects of low to moderate alcohol exposure
Despite extensive research, a direct correlation between low to moderate prenatal alcohol exposure (PAE) and Fetal Alcohol Spectrum Disorders has been elusive. Conflicting results are attributed to a lack of accurate and detailed data on PAE and incomplete information on contributing factors. The public health effectiveness of policies recommending complete abstinence from alcohol during pregnancy is challenged by the high frequency of unplanned pregnancies, where many women consumed some alcohol prior to pregnancy recognition. There is a need for research evidence emphasizing timing and dosage of PAE and its effects on child development
Silyl trifluoromethanesulfonate-activated para-methoxybenzyl methyl ether as an alkylating agent for thiols and aryl ketones
para-Methoxybenzyl methyl ether acts as an alkylating agent for thiols in the presence of trimethylsilyl trifluoromethanesulfonate and trialkylamine base in good yields (58-96%). Aryl ketones are alkylated under similar conditions, probably through an enol silane intermediate, also in high yields (67-95%). The active alkylating species is likely a p-methoxybenzyl cation
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Developing a scalable training model in global mental health: pilot study of a video-assisted training Program for Generalist Clinicians in Rural Nepal.
BackgroundIn low- and middle-income countries, mental health training often includes sending few generalist clinicians to specialist-led programs for several weeks. Our objective is to develop and test a video-assisted training model addressing the shortcomings of traditional programs that affect scalability: failing to train all clinicians, disrupting clinical services, and depending on specialists.MethodsWe implemented the program -video lectures and on-site skills training- for all clinicians at a rural Nepali hospital. We used Wilcoxon signed-rank tests to evaluate pre- and post-test change in knowledge (diagnostic criteria, differential diagnosis, and appropriate treatment). We used a series of 'Yes' or 'No' questions to assess attitudes about mental illness, and utilized exact McNemar's test to analyze the proportions of participants who held a specific belief before and after the training. We assessed acceptability and feasibility through key informant interviews and structured feedback.ResultsFor each topic except depression, there was a statistically significant increase (Î) in median scores on knowledge questionnaires: Acute Stress Reaction (Î = 20, p = 0.03), Depression (Î = 11, p = 0.12), Grief (Î = 40, p < 0.01), Psychosis (Î = 22, p = 0.01), and post-traumatic stress disorder (Î = 20, p = 0.01). The training received high ratings; key informants shared examples and views about the training's positive impact and complementary nature of the program's components.ConclusionVideo lectures and on-site skills training can address the limitations of a conventional training model while being acceptable, feasible, and impactful toward improving knowledge and attitudes of the participants
Line-of-sight velocity distributions of low-luminosity elliptical galaxies
The shape of the line-of-sight velocity distribution (LOSVD) is measured for a sample of 14 elliptical galaxies, predominantly low-luminosity ellipticals. The sample is dominated by galaxies in the Virgo cluster but also contains ellipticals in nearby groups and low density environments. The parameterization of the LOSVD due to Gerhard and van der Marel and Franx is adopted, which measures the asymmetrical and symmetrical deviations of the LOSVD from a Gaussian by the amplitudes h3 and h4 of the Gauss-Hermite series. Rotation, velocity dispersion, h3 and h4 are determined as a function of radius for both major and minor axes. Non-Gaussian LOSVDs are found for all galaxies along the major axes. Deviations from a Gaussian LOSVD along the minor axis are of much lower amplitude if present at all. Central decreases in velocity dispersion are found for three galaxies. Two galaxies have kinematically-decoupled cores: NGC 4458 and the well-known case of NGC 3608
Implementation of on-site velocity boundary conditions for D3Q19 lattice Boltzmann
On-site boundary conditions are often desired for lattice Boltzmann
simulations of fluid flow in complex geometries such as porous media or
microfluidic devices. The possibility to specify the exact position of the
boundary, independent of other simulation parameters, simplifies the analysis
of the system. For practical applications it should allow to freely specify the
direction of the flux, and it should be straight forward to implement in three
dimensions. Furthermore, especially for parallelized solvers it is of great
advantage if the boundary condition can be applied locally, involving only
information available on the current lattice site. We meet this need by
describing in detail how to transfer the approach suggested by Zou and He to a
D3Q19 lattice. The boundary condition acts locally, is independent of the
details of the relaxation process during collision and contains no artificial
slip. In particular, the case of an on-site no-slip boundary condition is
naturally included. We test the boundary condition in several setups and
confirm that it is capable to accurately model the velocity field up to second
order and does not contain any numerical slip.Comment: 13 pages, 4 figures, revised versio
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